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Title:
MAGNETRON SPUTTERING SOURCE FOR INSULATING TARGET MATERIALS
Document Type and Number:
WIPO Patent Application WO/2018/175689
Kind Code:
A1
Abstract:
A magnetron sputtering source for sputtering a target includes a magnetically permeable material yoke member and a first magnet positioned on said yoke member and having a north-south magnetic orientation that is perpendicular to the yoke member. A second magnet positioned on the yoke member spaced apart from the first magnet and having a north-south magnetic orientation that is perpendicular to the yoke member and opposite the magnetic orientation of the first magnet. The resulting magnetron sputtering source produces a magnetic field having magnetic flux lines that define a sputtering region adjacent the front surface of the target and within the target body. The magnetic flux lines have substantial perpendicular components to the yoke member adjacent the front surface of the target and within the target body and having generally uniform magnetic flux density adjacent the front surface of the target and within the target body.

Inventors:
FAN, Qi Hua (2697 Elderberry Dr, East Lansing, Michigan, 48864, US)
BILLS, Braden (7717 W 42nd St, Sioux Falls, South Dakota, 57106, US)
Application Number:
US2018/023710
Publication Date:
September 27, 2018
Filing Date:
March 22, 2018
Export Citation:
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Assignee:
APPLIED PLASMA EQUIPMENT (7717 W 42nd St, Sioux Falls, South Dakota, 57106, US)
International Classes:
C23C14/35; C23C14/34; H01F7/02; H01F7/08; H01J25/50; H01J37/34
Foreign References:
US6491801B12002-12-10
US5415754A1995-05-16
US20150107992A12015-04-23
US20040035692A12004-02-26
US20130180851A12013-07-18
US6338781B12002-01-15
Attorney, Agent or Firm:
COLEMAN, Kyle S. et al. (Goodhue, Coleman & Owens P. C.,12951 University Ave.,Suite 20, Clive Iowa, 50325, US)
Download PDF:
Claims:
What is claimed is:

1. A magnetron sputtering source and a plasma associated with the source for sputtering a target, the target having a front surface, a body, and a back surface, the magnetron sputtering source comprising:

a generally plate-shaped yoke member defining a reference plane parallel to a longitudinal axis of the target, the yoke member comprises a magnetically permeable material;

a first magnet positioned on said yoke member, said first magnet having a north-south magnetic orientation that is perpendicular to said reference plane, outermost edges and a center; and a second magnet positioned on said yoke member spaced apart from said first magnet, said second magnet having a north-south magnetic orientation that is perpendicular to said reference plane and opposite the magnetic orientation of said first magnet, outermost edges and a center, said first and second magnets being spaced apart to produce a magnetic field having a plurality of magnetic flux lines that define a sputtering region adjacent the front surface of the target and within the target body,, the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to said reference plane adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

2. The magnetron sputtering source of claim 1, further comprising:

a ratio between the combined surface area parallel to said reference plane of said first and second magnets and surface area parallel to said reference plane of the sputtering magnetron source defined by the outermost edges furthest from the center, wherein the ratio is between 0.5 and 0.999 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to said reference plane adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

3. The magnetron sputtering source of claim 1, further comprising:

a ratio between the combined surface area parallel to said reference plane of said first and second magnets and surface area parallel to said reference plane of the sputtering magnetron source defined by the outermost edges furthest from the center, wherein the ratio is between 0.8 and 0.999 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to said reference plane adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

4. The magnetron sputtering source of claim 1, further comprising:

a ratio between the combined surface area parallel to said reference plane of said first and second magnets and surface area parallel to said reference plane of the said sputtering magnetron source defined by the outmost edges furthest from the center, wherein the ratio is between 0.85 and 0.95 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to said reference plane adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

5. A method of sputtering, comprising the steps of:

establishing a low pressure sputtering atmosphere in a sputtering chamber having a target with a front surface, a body, and a back surface;

creating a plasma over a sputtering region on the target located within the sputtering chamber; and generating a magnetic field having a plurality of magnetic flux lines adjacent the front surface of the target and within the target body, the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target and adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

6. A magnet assembly for sputtering a target in a magnetron sputtering apparatus, the assembly comprising:

a target having a front surface, a body, and a back surface, said magnet assembly being positioned adjacent the back surface of the target and generating a magnetic field having a plurality of magnetic flux lines that define a sputtering region adjacent the front surface of the target and within the target body, the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target and adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

7. The magnet assembly of claim 6, further comprising:

a generally plate-shaped magnetically permeable yoke member parallel to the back surface of the target;

a first magnet having a north-south magnetic orientation that is perpendicular to the back surface of the target, a center and outermost edges; and

a second magnet positioned apart from said first magnet and having a north-south magnetic

orientation that is perpendicular to the back surface of the target and opposite the magnetic orientation of said first magnet, a center and outermost edges.

8. The magnet assembly of claim 7, further comprising:

a ratio between the combined surface area parallel to the back surface of the target of said first and second magnet and surface area parallel to the back surface of the target of the sputtering magnetron source defined by the outermost edges furthest from the center, wherein the ratio is between 0.5 and 0.999 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

9. The magnet assembly of claim 7, further comprising:

a ratio between the combined surface area parallel to the back surface of the target of said first and second magnet and surface area parallel to the back surface of the target of the sputtering magnetron source defined by the outermost edges furthest from the center, wherein the ratio is between 0.8 and 0.999 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

10. The magnet assembly of claim 7, further comprising:

a ratio between the combined surface area parallel to the back surface of the target of said first and second magnet and surface area parallel to the back surface of the target of the sputtering magnetron source defined by the outermost edges furthest from the center , wherein the ratio is between 0.85 and 0.95 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

11. The magnet assembly of claim 6, wherein the target is circular, has an axis of symmetry, and a concentric center, and wherein said magnetic lobe is concentric with the axis of symmetry of the circular target.

12. The magnet assembly of claim 11, further comprising:

a circular magnetically permeable yoke member having an axis of symmetry aligned with the axis of symmetry of the circular target and parallel to the back surface of the target;

a first magnet mounted at or near the center of said yoke member having a north-south magnetic orientation that is perpendicular to the back surface of the target; and

a second magnet mounted to an outer periphery of said yoke member, concentric with said first magnet, and having a north-south orientation that is perpendicular to the back surface of the target and opposite the magnetic orientation of said central magnet.

13. The magnetron sputtering source of claim 12, further comprising:

a ratio between the combined surface area parallel to the back surface of the target of said first and second magnets and surface area parallel to the back surface of the target of the sputtering magnetron source defined by outermost edges of said second magnet furthest from the concentric center, wherein the ratio is between 0.5 and 0.999 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

14. The magnetron sputtering source of claim 12, further comprising:

a ratio between the combined surface area parallel to the back surface of the target of said first and second magnets and surface area parallel to the back surface of the target of the sputtering magnetron source defined by outermost edges of said second magnet furthest from the concentric center, wherein the ratio is between 0.8 and 0.999 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

15. The magnetron sputtering source of claim 12, further comprising: a ratio between the combined surface area parallel to the back surface of the target of said first and second magnets and surface area parallel to the back surface of the target of the sputtering magnetron source defined by the outermost edges of said second magnet furthest from the concentric center, wherein the ratio is between 0.85 and 0.95 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

16. The magnet assembly of claim 6, wherein the target is rectangular and includes a longitudinal axis and transverse axis, said magnet assembly including a linear center section and two end sections, said linear center section being aligned with the longitudinal axis of the target, and wherein each said magnetic lobe includes two linear sections disposed in parallel, spaced-apart relation on opposite sides of the longitudinal axis of the rectangular target, respective parallel linear sections of respective magnetic lobes being joined at either end by respective semi-circle end sections; whereby said magnetic lobe confines the plasma and is oval shaped.

17. The magnetic assembly of claim 16, further comprising:

an elongated magnetically permeable yoke member having an elongated center section and two semicircular end sections, the elongated center section of said yoke member being aligned with the longitudinal axis of the rectangular target and parallel to the back surface of the rectangular target; a first magnet mounted at or near the center of said yoke member, said first magnet including an elongated center magnet member that is aligned with the longitudinal axis of the rectangular target, a first cylindrical magnet member disposed at one end of said elongated center magnet, and a second cylindrical magnet member disposed at the other end of said elongated center magnet, said elongated center magnet member and said first and second cylindrical magnet members having north-south magnetic orientations that are perpendicular to the back surface of the target; and a second magnet mounted to an outer periphery of said yoke member, said second magnet being positioned apart from said first magnet assembly, and wherein said second magnet has a north- south magnetic orientation that is perpendicular to the back surface of the target and opposite the magnetic orientation of said first magnet.

18. The magnetron sputtering source of claim 17, further comprising:

a ratio between the combined surface area parallel to the back surface of the target of said first and second magnets and surface area parallel to the back surface of the target of the sputtering magnetron source defined by outermost edges of said second magnet furthest from center, wherein the ratio is between 0.5 and 0.999 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

19. The magnetron sputtering source of claim 17, further comprising:

a ratio between the combined surface area parallel to the back surface of the target of said first and second magnets and surface area parallel to the back surface of the target of the sputtering magnetron source defined by outermost edges of said second magnet furthest from center, wherein the ratio is between 0.8 and 0.999 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

20. The magnetron sputtering source of claim 17, further comprising:

a ratio between the combined surface area parallel to the back surface of the target of said first and second magnets and surface area parallel to the back surface of the target of the sputtering magnetron source defined by outermost edges of said second magnet furthest from center, wherein the ratio is between 0.85 and 0.95 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

21. The magnet assembly of claim 6, wherein the target is rectangular and includes a longitudinal axis and transverse axis, said linear center section being aligned with the longitudinal axis of the target, and wherein said magnetic lobe being aligned with the longitudinal axis of the target; whereby said magnetic lobe confines the plasma.

22. The magnetic assemble of claim 21, further comprising:

an elongated magnetically permeable yoke member being aligned with the longitudinal axis of the rectangular target and parallel to the back surface of the rectangular target;

a first magnet positioned on said yoke member, said first magnet being aligned with the longitudinal axis of the rectangular target, and wherein said elongated first magnet member having north-south magnetic orientations that is perpendicular to the back surface of the target; and

a second magnet positioned on said yoke member, said second magnet being aligned with the longitudinal axis of the rectangular target, and wherein said elongated second magnet has a north- south magnetic orientation that is perpendicular to the back surface of the target and opposite the magnetic orientation of said first magnet.

23. The magnetron sputtering source of claim 22, further comprising:

a ratio between the combined surface area parallel to the back surface of the target of said first and second magnets and surface area parallel to the back surface of the target of the sputtering magnetron source defined by the outermost edges of said first and second magnets, wherein the ratio is between 0.5 and 0.999 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

24. The magnetron sputtering source of claim 22, further comprising:

a ratio between the combined surface area parallel to the back surface of the target of said first and second magnets and surface area parallel to the back surface of the target of the sputtering magnetron source defined by the outermost edges of said first and second magnets, wherein the ratio is between 0.8 and 0.999 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

25. The magnetron sputtering source of claim 22, further comprising:

a ratio between the combined surface area parallel to the back surface of the target of said first and second magnets and surface area parallel to the back surface of the target of the sputtering magnetron source defined by the outermost edges of said first and second magnets, wherein the ratio is between 0.85 and 0.95 to 1, wherein the magnetic flux lines form a magnetic lobe located within said sputtering region having substantial perpendicular components to the back surface of the target adjacent the front surface of the target and within the target body and having generally uniform perpendicular magnetic flux density adjacent the front surface of the target and within the target body, whereby said magnetic lobe confines the plasma.

Description:
MAGNETRON SPUTTERING SOURCE FOR INSULATING TARGET MATERIALS

Field of the Invention

Sputtering of target materials can be improved with a magnetic flux that confines electrons near the target surface, where the confined electrons enhance ionization of the sputtering gas. This invention relates generally to an improved magnetic flux to increasing sputtering efficiency, especially for insulating target materials.

Background

Conventional magnetron sputtering sources are configured so that conductive target materials are sputtered, i.e. eroded, the most where the magnetic field parallel component is at a maximum and the perpendicular component is at a minimum. The conventional magnetron configuration generally results in efficient and rapid sputtering of conductive target materials. However, this is not the case when conventional magnetron configurations are used to sputter insulating target materials. Improperly designed magnetrons result in a narrow erosion profile, which is inefficient and adds significant cost and limits capacity and yield of mass production. Therefore, what is needed is novel magnetron sputtering sources for insulating target materials that alleviate these issues.

Summary

Therefore, it is a primary object, feature, or advantage of the present invention to improve over the state of the art.

It is a further object, feature, or advantage of the present invention to provide an improved magnetron sputtering source having increased utilization of insulator targets.

It is a still further object, feature, or advantage of the present invention to provide an improved magnetron sputtering source having increased deposition rate and wider target erosion profile of insulator targets.

Another object, feature, or advantage is to provide a magnetron sputtering source having an improved magnetic field shape optimized for insulator targets. Compared to conventional magnetron sputtering sources, the magnetic field shape of this invention has substantial perpendicular components adjacent the front surface of the target and within the target body and having generally uniform magnetic flux density adjacent the front surface of the target and within the target body.

Yet another object, feature, or advantage is to provide a magnetron sputtering source having an improved magnetic field shape optimized for insulator targets, but without the need to resort to oscillating the magnetic field over the surface of the target or to oscillate the target itself.

One or more of these and/or other objects, features, or advantages of the present invention will become apparent from the specification and claims that follow. No single embodiment need provide each and every object, feature, or advantage. Different embodiments may have different objects, features, or advantages. Therefore, the present invention is not to be limited to or by any objects, features, or advantages stated herein.

Brief Description of the Drawings

FIGS. l(a)-(c) are pictorial representations showing the erosion profile of metal and insulating target materials in relation to the magnet flux density produced by a conventional magnetron sputtering source of the prior art;

FIG. 2(a)-(f) are pictorial representations showing the various configurations of a magnet;

FIGS. 3(a)-(b) are the schematic cross section view of an improved magnetron sputtering source and the produced magnetic field. Only half of the configuration is shown since the configuration is symmetrical;

FIGS. 4(a)-(b) are the schematic cross section view of another magnetron sputtering source and the produced magnetic field. Only half of the configuration is shown since the configuration is symmetrical;

FIG. 5 is a schematic cross section view of another improved magnetron sputtering source and the produced magnetic field;

FIG. 6 is a schematic cross section view of another magnetron sputtering source and the produced magnetic field. The color gradient shows the magnetic flux density is uniform and highest nearest the magnets;

FIG. 7 is a pictorial representation showing the apex of magnetic field lines produced by a magnetron sputtering source in accordance with an illustrative aspect of the present invention.

FIG. 8 is a schematic cross section view of an externally mounted configuration of the magnetron sputtering source shown in FIG. 6;

FIG. 9 is a pictorial representation comparing the erosion profile of quartz targets sputtered by the magnetron sputtering source of FIG. 4 and a commercially available magnetron sputtering product; and

FIG. 10 is a schematic cross section view of an internally mounted configuration of the magnetron sputtering source of FIG. 4.

Detailed Description

Parallel and perpendicular are used throughout to describe the magnetic field components and are always in relation to the target surface unless explicitly stated otherwise. Alternatively, horizontal and vertical are sometimes used in place of parallel and perpendicular, respectively.

Magnetron sputtering is characterized by a plasma discharge with non-uniform electric and magnetic fields that collaboratively confine electrons and drive gas ions to bombard the target surface. The magnetic field is most commonly generated by permanent magnets, while the electric field is established between the cathode (target) and the anode (substrate) by external direct current (DC), radio frequency ( F), high power pulse, or a combination of them. As the sputtering target surface is usually flat (planar magnetron) or cylindrical (rotary magnetron), the strength and shape of the magnetic flux density determine plasma characteristics (energy, density, and distribution of ions and electrons). Consequently, target erosion is directly related to the magnetic field.

Figure 1 shows the erosion profile of metal and insulating target materials in relation to the magnetic flux density produced by a conventional magnetron sputtering source configuration. The erosion profile shows the remaining target 20 material and the eroded regions 21 after the sputtering process. Figure lc shows a conventional magnetron sputtering source and resultant magnetic field lines. Figure la shows the well- known V-shaped erosion profile of a metal target when sputtered using a conventional magnetron. In magnetron sputtering of metals, the conventional V-shape erosion is attributed to magnetic field confinement of high energy electrons to regions where the perpendicular component 24 is close to zero. That is, the metal target was deeply eroded, i.e. sputtered, where the magnetic field parallel component 25 was at a maximum and the perpendicular component 24 was at a minimum. This finding led to the basic principle of magnetron configuration that magnetic parts (magnets and steel yokes) should be configured in such a way that the resulting magnetic flux over the target surface is parallel to the target surface with minimal perpendicular magnetic flux points. However, the conventional magnetron configuration does not produce the V-shaped erosion profile when sputtering insulating target materials as shown in Figure lb. In fact, the insulating target was essentially the least eroded where the metal target was most eroded. The insulating target had the most erosion near the magnetic poles, where the magnetic flux was perpendicular 24 - the opposite case compared to the metal target. This fact indicates the existence of fundamental differences between magnetron discharges when sputtering conductive or insulative materials. Therefore, a magnetron suitable for sputtering of conductive materials is not suitable for sputtering of insulating materials.

When a conventional magnetron is used to sputter insulating targets, this results in a narrow erosion profile (see Figure lb) due to the improper distribution of the magnetic field over the target surface. There are three major production consequences with such a narrow sputtering erosion profile: 1) the expensive target material is not efficiently used resulting in frequent target replacement, which is labor and time intensive; 2) the deposition rate is very low and varies over time; and 3) the sputtered target species can be re-deposited onto the target surface where it is less sputtered, forming suboxide and creating defects in the resulting films. These issues due to the narrow erosion profile of insulating materials when using conventional magnetrons add significant cost and limit capacity and yield of mass production.

Sputtering insulator materials using conventional magnetrons (e.g. Figure lc) results in target erosion (Figure lb) mostly occurring near the magnetic poles where perpendicular magnetic flux component 24 is high. This indicates a uniform and dense perpendicular magnetic flux component 24 would promote target erosion uniformity of insulator targets. This differs fundamentally from the conventional belief that, for sputtering magnetrons to produce uniform target erosion, they need flat magnetic flux consisting of small perpendicular component 24 and large parallel component 25.

Multiple embodiments of the invention will be described, but what they all have in common is that they produce a uniform and dense magnetic flux with maximum perpendicular component and minimum parallel component- the opposite case compared to conventional magnetron configuration. A preferred use of the embodiments is for F magnetron sputtering of planar targets, but the embodiments are not limited to any one of the preferred uses and therefore can be used in multiple configurations, such as but not limited to:

• alternating current (AC) with frequencies higher or lower than 13.56 MHz, DC, pulsed power, or a combination of them;

• balanced or/and unbalanced magnetron configurations;

• use of one or more magnetrons;

• magnetron sputtering sources of any shape, such as circular, elliptical, cylindrical, rectangular, triangular, trapezoidal with sharp, e.g. square, or round corners or/and edges, and without or with a hole or holes;

• planar or rotary targets of any shape, such as circular, elliptical, cylindrical, rectangular, triangular, trapezoidal with sharp, e.g. square, or round corners or/and edges, and without or with a hole or holes, target of any thickness, though typically between 0.125 and 0.250 inches, and targets with a flat or non-flat, i.e. machined, profile; and

• other types of sputter deposition, such as triode sputtering, reactive sputtering, ion-assisted sputtering, high-target-utilization sputtering (HiTUS), high-power-impulse magnetron sputtering (HIPIMS) or/and gas flow sputtering, such as with hollow cathodes.

A magnet is defined as one or more magnetic members that produce a magnetic field, such as permanent magnet or electromagnets 26, with or without one or more magnetic permeable material members 30, such as steel, or a combination of them in communication with each other such that they have the same north-south magnetic orientation. Figure 2 shows example magnet configurations but the examples are not limited to those shown and therefore there can be multiple configurations. For example, a magnet could be a single magnet member 26 of any shape, such as cylindrical or cuboid, and with north-south magnetic orientation (Figure 2a). A magnet could be two magnetic members 26 combined, such as stacked one on top of the other so that they have the same north-south magnetic orientation (Figure 2b). A magnet could be a magnetic member 26 and a magnetic permeable material member 30 combined so that they have the same north-south magnetic orientation (Figure 2c). A magnet could be a plurality of magnetic members 26 and a magnetic permeable material member 30 in any shape, such as rectangular, circular, or elliptical, and with the magnetic members 26 arranged in the center of the magnetic permeable material member 30 (Figure 2d, top down view), staggered (Figure 2e, top down view), or any arrangement so that they have the same north-south magnetic orientation. A magnetic could be comprised of a plurality of magnetic members 26 and magnetic permeable material members 30 with the same north-south magnetic orientation (Figure 2f).

Accordingly, at least one exemplary configuration of the invention is shown pictorially in Figure 3. Only half of the magnetic configuration is shown since it is symmetrical. At least one preferred configuration of Figure 3 is a circular configuration, but it can also be configured in other shapes. The center 27 and outer 28 magnets are connected to a steel yoke 31 that shunts the magnetic field. The yoke 31 is typically steel, but it can be any suitable magnetic material. The steel yoke 31 in Figure 3a is shown to have a flat profile, but it could also have a non-flat profile. The outer magnet 28 can be a ring magnet or a plurality of magnets. The center magnet (first magnet) 27 connects to the backing plate 42. The backing plate is a non-magnetic material, such as copper. Alternatively, there could be no backing plate and the center magnet 27 connects directly to the target material 20, or there could be a gap between the center magnet 27 and the backing plate 42 or target 20. The outer magnet 28 can be at the end of the steel yoke 31 (Figure 3a) or it can be at any location from the end of the steel yoke 31. The outer magnet 28 connects to a second magnetic material 30, preferably steel, on the opposite end of the magnet 28 as the steel yoke 31 and this magnetic material 30 can have a different width than the outer magnet 28. That is, the second magnetic piece 30 can have a larger width than the outer magnet 28 as shown in Figure 3a, or the second magnetic piece 30 can have a smaller width or the same width as the outer magnet 28. The second magnetic piece 30 can be a continuous piece or could be a disc with or without a hole in the middle. The second magnetic piece 30 can be connected to the backing plate 42 or target 20 if no backing plate 42 is used, or they could be disconnected so that there is a gap. The combination of the outer magnet 28 and second magnetic material piece 30 is the second magnet. Figure 3a shows the magnetic poles closest to the target 20 to be south and north for the outer 28 and center 27 magnets, respectively, but the magnetic poles can be switched with no adverse effect. The gap 44 between the magnets can be filled with a fluid, typically air, but it could also be another gas, such as Argon or Nitrogen, a liquid, such as water or another coolant, or in vacuum. Figure 3b shows the magnetic field lines of a configuration of the present invention with a high density of perpendicular magnetic flux 24 uniformly spread across the entire target 20 surface.

Another exemplary configuration of the present invention is shown pictorially in Figure 4. Only half of the magnetic configuration is shown since it is symmetrical. At least one preferred configuration of Figure 4 is circular, but it can also be configured in other shapes. The center 27 and outer 28 magnets are connected to a steel yoke 31 that shunts the magnetic field. The yoke 31 is typically steel, but it can be any magnetic material. The steel yoke 31 has a non-flat profile. Figure 4a shows a steel yoke 31 that is thicker and thinner where it connects to the center 27 and outer 28 magnets, respectively. Alternatively, the steel yoke 31 can be thicker or thinner where it connects to the outer 27 and center 28 magnets, respectively, or it can have a flat profile. The outer magnet 28 can be a ring magnet or a plurality of magnets. The center magnet (first magnet) 27 connects to the backing plate 42. The backing plate 42 is a non-magnetic material, such as copper. Alternatively, there could be no backing plate 42 and the center magnet 27 connects directly to the target material 20, or there could be a gap between the center magnet 27 and the backing plate 42 or target 20. The outer magnet 28 can be at the end of the steel yoke 31 or it can be at any location from the end of the steel yoke 31 (Figure 4a). The outer magnet 28 connects to a second magnetic material 30, preferably steel, on the opposite end of the magnet 28 as the steel yoke 31 and this magnetic material 30 can have a different width than the outer magnet 28. That is, the second magnetic piece 30 can have a larger width than the outer magnet 28 as shown in Figure 4a, or the second magnetic piece 30 can have a smaller or the same width as the outer magnet 28. The second magnetic piece 30 can be a continuous piece or could be a disc with or without a hole in the middle. The second magnetic piece 30 can be connected to the backing plate 42 or target 20 if no backing plate 42 is used, or they could be disconnected so that there is a gap. The combination of the outer magnet 28 and second magnetic material piece 30 is the second magnet. Figure 4a shows the magnetic poles closest to the target 20 to be south and north for the center 27 and outer 28 magnets, respectively, but the magnetic poles can be switched with no adverse effect. The gap 44 between the magnets can be filled with a fluid, typically air, but it could also be another gas, such as Ar, a liquid, such as water or another coolant, or in vacuum. Figure 4b shows the magnetic field lines of a configuration of the present invention with a high density of perpendicular magnetic flux 24 uniformly spread across the entire target 20 surface.

In accordance with another exemplary aspect of the present invention, a configuration akin to afforementioned that doesn't have the second magnetic material piece 30 on the opposite end of the outer magnet 28 as the steel yoke 31 is contemplated. The outer magnet 28 could be connected to the backing plate 42 or to the target 20 if no backing plate 42 is used, or they could not be connected so that there is a gap.

Another exemplary aspect of the present invention is pictorially shown in Figure 5. At least one preferred configuration of Figure 5 is rectangular, specifically the long section, but it can also be used at the rectangular ends and be configured in other shapes, such as a circular configuration. The arrows denote the magnet's polarity. A first set of inner 29 and outer 28 magnets with opposite polarity are connected to a steel yoke 31. The yoke 31 is typically steel, but it can be any magnetic material. The yoke 31 can have a flat or non-flat profile. A second magnetic permeable material 30, typically steel, is connected to the opposite end of the first set of inner 29 and outer 28 magnets as the steel yoke 31. The second magnetic material 30 can be a single piece, such as a plate or disc with or without a hole in the center, or it can be multiple pieces of material. A second set of inner 29 and outer 28 magnets are connected on the same plane as the second set of magnetic permeable piece(s) 30. The combination of the second set of magnetic permeable piece(s) 30 and second set of inner 29 and outer 28 magnets can have the same width as the first set of inner 29 and outer 28 magnets as shown in Figure 5, or they can collectively have a different width than the first set of inner 29 and outer 28 magnets. The second set of inner 29 and outer 28 magnets have the same polarity as the first set of inner 29 and outer 28 magnets that they are connected to. The first magnet is the combination of first and second sets of inner magnets 29 and second magnetic material 30 that have the same north-south magnetic orientation. The second magnet is the combination of first and second sets of outer magnets 28 and second magnetic material 30 that have the same north-south magnetic orientation and magnetic orientation that is opposite of said first magnet. Figure 5 shows a first gap 44 between the inner (first) and outer (second) magnets, and a second gap 45 adjacent to the inner magnet and on the opposite side as the first gap 44. The second gap 45 is in the center of the magnetron sputtering source. Figure 5 shows that the second set of inner 29 and outer 28 magnets are furthest apart from each other adjacent the second gap 45 and adjacent the outer edge, respectively, while the second magnetic permeable piece(s) 30 are adjacent the first gap 44. The thickness and magnet strengths may be different for each layer. The second set of inner 29 and outer 28 magnets and second magnetic permeable piece(s) 30 are connected to a backing plate 42 which is connected to the target material 20. Alternatively, the second set of inner 29 and outer 28 magnets and second magnetic permeable piece(s) 30 can be connected directly to the target material 20 without a backing plate 42. The gaps 44 and 45 can be filled with a fluid, typically air, but it could also be another gas, such as Ar, a liquid, such as water or another coolant, or in vacuum. Alternatively, there could be no gap 44 or 45. Figure 5 shows the magnetic field lines with a high density of perpendicular magnetic flux 24 uniformly spread across the entire target 20 surface.

Another exemparly aspect of the present invention is akin to the configuration illustrated in Figure 5 and discussed above, where the second set of inner 29 and outer 28 magnets is near the first gap 44 and the second magnetic permeable piece(s) 30 are furthest apart from each other adjacent the second gap 45 and adjacent the outer edge. Alternatively, the second set of inner 29 and outer 28 magnets can be located in any position, and have multiple magnetic permeable piece(s) 30 on either side.

Another exemplary aspect of the present invention is akin to the configuration shown in Figure 5 and subsequently described alternative configurations of the same, where there are more than one set of second inner 29 and outer 28 magnets and magnetic permeable piece(s) 30. For examle, the second set of inner 29 and outer 28 magnets could include two inner 29 magnets with the same polarity and two outer 28 magnets with the same polarity on either side for a total of four magnets. There could then be multiple pieces of magnetic permeable material 30 in between the magnets. Similarily, the second set of inner 29 and outer 28 magnets could be comprised of three magnets per side, or four, and so on. The number of inner 29 and outer 28 magnets do not need to be the same.

Other exemplary aspect of the present invention are akin to the configuration shown in Figure 5 and subsequenlty described alternative configurations of the same, where the position of the first set of inner 29 and outer 28 magnets is switched with the second set of inner 29 and outer 28 magnets and second set of magnetic permeable piece(s) 30. That is, the second set of inner 29 and outer 28 magnets and second set of magnetic permeable piece(s) 30 are connected to the steel yoke 31 and the first set of inner

29 and outer 28 magnets are connected to the backing plate 42 or target material 20.

Still other exemplary aspects of the present invention are akin to the configuration shown in Figure 5 and subsequently described alternative configurations of the same, where the first set of inner 29 and outer 28 magnets is duplicated and replaces the second set of inner 29 and outer 28 magnets and magnetic permeable piece(s) 30. Similarly, the second set of inner 29 and outer 28 magnets and magnetic permeable pieces 30 can be duplicated and replaces the first set of inner 29 and outer 28 magnets. The thickness and magnet strengths may be different for each layer.

Still other exemplary aspects of the present invention can include configurations akin to those shown in Figure 5 and subsequently described alternative configurations of the same, where there are multiple layers of the first set of inner 29 and outer 28 magnets and/or the second set of inner 29 and outer 28 magnets and magnetic permeable piece(s) 30 connected to each other.

Yet other exemplary aspects of the present invention can include configurations akin to those shown in Figure 5 and subsequently described alternative of the same, where the inner 29 and outer 28 magnetic strengths and/or configurations as described above can be different in the linear section than the end sections.

Another exemplary aspect of the present invention is shown pictorially in Figure 6. The center 27 and outer 28 magnets are connected to a steel yoke 31 in Figure 6. The yoke 31 is typically steel, but it can be any magnetic material. The steel yoke 31 in Figure 6 is shown to have a flat profile, but it could also have a non-flat profile. The end of the center magnet (first magnet) 27 opposite to the steel yoke 31 has a non- flat profile. Figure 6 shows the center magnet 27 to have a V-shaped profile, but the profile could also be U-shaped or similar. In three dimensions, the V- or U-shaped center magnet 27 can be a cone or non-cone shape. That is, the non-cone shape maintains the V- or U-shape from end-to-end of the magnet analogous to a valley. For example, the cone shaped center magnet 27 can be used in a circular magnetron configuration and a semi-circle cone shaped can be used at the ends of the rectangular magnetron configuration, and the non-cone shaped center magnets 27 can be used in the long, straight section of the rectangular magnetron configuration. The outer magnet 28 connects to a second magnetic material 30, preferably steel, on the opposite end of the magnet 28 as the steel yoke 31 and this magnetic material

30 can have a different width than the outer magnet 28. That is, the second magnetic material 30 can have a larger width than the outer magnet 28, or the second magnetic piece 30 can have a smaller or the same width as the outer magnet 28. The second magnetic piece 30 can be a continuous piece or could be a disc with or without a hole in the middle. The second magnetic material 30 can be connected to the backing plate 42 or target 20 if no backing plate 42 is used, or they could be disconnected so that there is a gap. Or there could be no second magnetic material 30 and the outer magnet 28 connect directly to the backing plate 42 or target 20 if no backing plate 42 is used, or they could be disconnected so that there is a gap. The combination of the outer magnet 28 and second magnetic material 30 is the second magnet. The gap 44 between the magnets can be filled with a fluid, typically air, but it could also be another gas, such as Ar, a liquid, such as water or another coolant, or in vacuum. Figure 6 shows the magnetic field lines with a high density of perpendicular magnetic flux 24 uniformly spread across the entire target 20 surface. The color gradient shows that the magnetic flux is uniform and has the highest density near the center 27 and outer 28 magnets. The target material 20 and backing plate 42 are not shown in Figure 6, though it is implied that they are included in a fully functional magnetron sputtering source.

Yet other exemplary aspects of the present invention can include configurations akin to those shown in Figures 3 - 6 and subsequently described alternative configurations of the same, where the position of the magnetic field lines apex, i.e. where the parallel component 25 of the magnetic flux lines is at a maximum, can shift either towards the configurations' center or edge as the magnetic field lines extend from the magnet 26 ends, through the target 20, and away from the target 20 surface as illustrated by Figure 7. If an illustrative line were to be drawn that intersects the apex of all the magnetic field lines, the line would be at angle to the target 20 surface, where the angle is somewhere between being parallel and perpendicular. The benefit would be that as the target 20 is sputtered, the least sputtered region, where the parallel component 25 of the magnetic field lines was at a maximum, i.e. the magnetic field lines apex, would shift as the target 20 is eroded. Therefore, over time as the target 20 is sputtered, a greater portion of the target 20 is eroded and increases the target 20 use efficiency.

Figure 8 shows an externally mounted sputtering cathode configuration with the magnetics of the configuration shown in Figure 6, though any of the afore-described configurations of the present invention could be used. The externally mounted configuration is advantageous in that the magnetics can be replaced without breaking vacuum and is useful for sputtering with multiple magnetrons. The cathode 46 is an electrically conductive and non-magnetic material, such as copper. The cathode 46 is mounted to the vacuum chamber wall 48 with an insulator 50 in between so as not to energize the vacuum chamber. The cathode 46 has cooling channels 52 that can circulate a chilled fluid, such as water. The target 20 can be placed on the cathode 46 directly or with a backing plate in between. Other features, such as the dark space shield 54, can be used to enhance the sputtering process.

According to one aspect of the present invention, operation of the configuration shown in Figure 4 was compared to a commercially available 2-inch magnetron cathode. The sputter parameters were held consistent for each magnetron, which were a sputtering time of 1 hour, F (13.56 M Hz) power of 75 watts, base pressure of 10 s Torr, working pressure of 10 "3 Torr, Argon gas flow of 10 SCCM (standard cubic centimeter per minute), and in a vacuum chamber. A new quartz target (acquired from Kurt J. Lesker company) was used for each sputter test. Figure 9 compares the erosion profile, as measured by a profilometer, of the quartz targets after the sputter test. The erosion profile shows the remaining target 20 material and the eroded regions 21 after the sputtering process. The target erosion profile in accordance with an exemplary aspect of the present invention and pictorially illustrated in Figure 9 - was wider and deeper than that produced by the commercially available magnetron and resulted in a 44.6% improvement of target eroded area. A silicon wafer substrate was used for each sputter test. The RMS roughness, as measured by an atomic force microscope, of the sputtered silicon oxide film surface was 0.172 nm and 0.194 nm for those of the present invention and the commercially available magnetrons, respectively. The film thicknesses, as measured by a profilometer, of the sputtered silicon oxide film surface were 473 nm and 275 nm for those of the present invention and the commercially available magnetrons, respectively. Thus, the deposition rates for those of the present invention and the commercially available magnetrons were 0.1313 nm/second and 0.0763 nm/second, respectively. The advantages of the present invention alleviate the three major production issues that arise when using a conventional magnetron: 1) the expensive target material is efficiently used so that fewer target replacements are needed to reduce labor and time costs; 2) the deposition rate is nearly doubled; and 3) the re-deposition of sputtered target species is significantly reduced with the wider erosion profile. Note that the sputter test was not optimized for the present invention as the test parameters were held constant for comparison with the commercially available magnetron. The sputtering process with the magnetron of the present invention can further be improved, such as increased sputtering rate and improved film quality, by optimizing the process parameters, such as the applied F or DC power, pressure, etc.

Figure 10 shows an internally mounted sputtering cathode configuration with the magnetics of the configuration shown in Figure 4, though any configuration of the present invention described herein could be used. The cathode 46 is an electrically conductive and non-magnetic material, such as copper or aluminum. The cathode 46 can be a single piece or multiple piece configuration. Figure 10 shows a cathode 46 configured from two pieces assembled with screws and sealed with an O-ring 56. The target material 20 is connected to the cathode 46 via a target clamp 58 and the target clamp 58 is connected to the cathode 46 via screws. In the cathode 46, opposite the target 20, is the cooling channel 52, which can be filled with a chilled fluid, typically water. The chilled fluid circulates through the cooling channel 52 via inlet and outlet connections and cooling fluid tubes. The cooling fluid tubes connect to the cooling channel 52, go through the mounting tube 60, and connect to an external chiller. The mounting tube can be hollow and is typically at atmospheric pressure. The cathode 46 is connected to a rod or wire that goes through the mounting tube 60 and connects to an external power source. The cooling fluid tubes 52 and cathode 46 connection can go through holes in the steel yoke 31. The cathode 46 and magnetron (magnet and steel pieces) is connected to an insulating material 50, such as Teflon, and sealed with an O-ring (56). The insulating material 50 has a hole in the center for the mounting tube 60. A flange 62 is connected to the insulating material 50 opposite the cathode 46 and magnetics and the entire assemble is secured with screws, where the screws have an insulated plug between the screw and flange 62 so as not to energize the flange 62. The flange 62/insulator 50 and flange 62/mounting tube 60 connections are sealed with O- rings 56. Other features, such as the dark space shield 54, can be used to enhance the sputtering process.

Additional variations to the configurations of the present invention can be their use with planar or rotary target configurations; static or dynamic, such as rotating, magnetics or magnetic piece(s); used with targets of any shape, such as circular or rectangular, or dimension (diameter, length, width, thickness); used with targets of any material type; magnetics or magnet piece(s) of any shape, dimension or magnetic strength; balanced and unbalanced magnetic fields; under any process conditions, e.g. pressure, RF or DC power, applied power, process gases; and externally or internally mounted magnetics or magnetic pieces(s).

A critical parameter in magnetron configuration is identification of suitable magnetic field strength. In general, a weak field will not be able to effectively confine high-energy electrons. However, a field too strong will lead to much reduced electron drift speed along the magnetic flux lines; this phenomenon can be qualitatively understood from the magnetic moment conservation of the gyro-electrons. Permanent magnets are known to have a wide range of magnetic strength measured by megagauss oersteds (MGO). Neodymium (NdFeB) and samarium cobalt (SmCo) rare-earth magnets with strength ranging from 20 MGO to 48 MGO are commercially available.

Additionally, an electron source, such as an electron gun or emitter, can supply electrons to accumulate on the target 20 surface. The electron source can be in combination with or independent of the magnetic field as described by the embodiments of the invention.

Additionally, an electron source, such as an electron gun or emitter, can supply electrons on the target 20 surface. For example, the electron source can supply electrons to the target 20 surface in a static pattern, whether that be the entire target 20 surface or select regions of the target surface, or it can supply electrons in a dynamic way, where the region of the supplied electrons changes with time, such as being scanned across the target 20 surface. The electron source can be in combination with or independent of the magnetic field as described by the embodiments of the invention

The configurations of the present invention can be used to sputter any material, but specifically insulator materials. An example insulator material is lithium phosphate (Li 3 P0 4 ) that can be sputtered into a lithium phosphorus oxynitride (LIPON) film to be used as a solid-state electrolyte for batteries. High quality LI PON films are obtained when the sputtering conditions result in a high degree of nitrogen (N2) disassociation, high electron temperature, and high impinging energy of N ions. High quality LIPON films have a smooth surface morphology without cracks, pinholes, or large micron sized features, a high ionic conductivity of about 2x10 s S/cm, and a low electrical conductivity of about 10 14 S/cm. The reported optimal sputtering process conditions to achieve high quality LIPON films when using conventional magnetrons are low power (< 100W), low vacuum pressure (< 10 mTorr), and low N2 flow rate (< 20 seem) to achieve a 'fast' deposition rate of about 0.5 A/s (Angstrom per second). The conventional way to increase the sputtering deposition rate is to increase the power and the pressure, however this decreases the quality of LIPON films when using conventional magnetrons. This is thought to be due to the reactive nature of LIPON deposition, where N 2 gas needs to be disassociated so that N can be incorporated into the sputtered L13PO4 target to form LIPON films. Advantages of the present invention can include achieving 'optimal' processing conditions (power, pressure N 2 flow rate) to sputter LIPON that will be relaxed with high density magnetic flux that is uniform across the entire L13PO4 surface when using one or more of the configurations of the present invention compared to conventional magnetrons where the magnetic flux density is predominately at the magnetic poles. As such, advantages of the present invention can produce a wider sputtering region and target erosion profile, e.g., see Figure 9, thus allowing higher power to be used to increase the deposition rate while maintaining high LIPON film quality. Further, N2 disassociation and incorporation into LIPON film may be enhanced with the configurations of the present invention compared to conventional magnetrons since the configurations of the present invention have a high density of magnetic flux near the target surface. The magnetics in the configurations of the present invention can be placed behind the substrate in addition to or independently as part of the magnetron sputtering source (i.e. magnetics behind the target).

Yet other exemplary aspects of the present invention can include configurations akin to those shown in Figures 3 - 6 and subsequently described alternative configurations of the same, where the ratio between the combined surface area parallel to the reference plane 80 (as viewed from the top down through the target) of the magnets and surface area of the sputtering magnetron source defined by the magnet edges furthest from the center is between 0.5 and 0.999 to 1, more preferably from 0.8 and 0.999 to 1, and yet more preferably from 0.85 and 0.95 to 1. That is, the sum of the first and second magnet surface areas parallel to the reference plane 80 (as viewed from the top down through the target) divided by the total surface area of the sputtering magnetron source defined by the magnet edges furthest from the center is between 0.5 and 0.999, more preferably from 0.8 and 0.999, and yet more preferably from 0.85 and 0.95. Alternatively, the ratio between the surface area of the space between the first and second magnets (gap 44) and surface area of the sputtering magnetron source defined by the magnet edge furthest from center is between 0.001 and 0.5 to 1, more preferably from 0.001 and 0.2 to 1, and yet more preferably from 0.05 and 0.15 to 1. That is, the surface area of the space between the first and second magnets (gap 44) divided by the total surface area of the sputtering magnetron source defined by the magnet edges furthest from the center is between 0.001 and 0.5, more preferably from 0.001 and 0.2, and yet more preferably from 0.05 and 0.15. These ratios produce magnetic flux lines that have substantial perpendicular components 24 adjacent the front surface of the target and within the target body and having generally uniform magnetic flux density adjacent the front surface of the target and within the target body. For example, Figures 3 and 4, assuming a circular configuration, show the radius 82 and diameter 84 of the first and second magnets, respectively, and the radius of the magnetron sputtering source 86, which are used to calculate their respective surface areas. And similarly, Figure 5, shows the widths of the first 83 and second 85 magnets and the width of the magnetron sputtering source 87, which are used to calculate their respective surface areas.