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Title:
MICROELECTROMECHANICAL SYSTEM (MEMS) BASED PROBE
Document Type and Number:
WIPO Patent Application WO/2015/095775
Kind Code:
A1
Abstract:
A probe assembly for probing a semiconductor device on a semiconductor wafer is provided. The probe assembly includes a stack of planar sheets each having a planar, sheet structure and defining a sheet tip thereof. The planar sheets are aligned and stacked to form a layered structure where the sheet tips are stacked to form a probe tip array. A dielectric layer is disposed between adjacent planar sheets to provide mechanical spacing and electrical isolation therebetween.

Inventors:
ROOT BRYAN J (US)
FUNK WILLIAM A (US)
Application Number:
PCT/US2014/071631
Publication Date:
June 25, 2015
Filing Date:
December 19, 2014
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
CELADON SYSTEMS INC (US)
International Classes:
H01L21/66; G01R1/073
Foreign References:
US20030112024A12003-06-19
US20090160473A12009-06-25
JP2013221858A2013-10-28
JP2010091541A2010-04-22
JP2013171005A2013-09-02
Attorney, Agent or Firm:
WONG, Bryan, A. (Schumann Mueller & Larson, P.C.,P.O. Box 290, Minneapolis MN, US)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. A conductive planar sheet for a probe, comprising:

a planar frame including links connected to each other at respective conjunctions; a resilient element connected to the planar frame; and

a sheet tip connected to the planar frame,

the planar frame having opposite ends and the sheet tip being located at one of the opposite ends, and the resilient element being configurable to modify a contact pressure of the sheet tip.

2. The conductive planar sheet according to claim 1, further comprising:

a planar support connected to the other of the opposite ends of the planar frame, the resilient element extending in a diagonal direction of the planar frame and connecting an upper conjunction and a lower conjunction of the conjunctions, the sheet tip being defined at one of the conjunctions of the planar frame different from the upper and lower conjunctions.

3. The conductive planar sheet according to claim 1, further comprising one or more contacts conductively connected to the sheet tip.

4. The conductive planar sheet according to claim 1, further comprising at least one alignment opening on the planar frame and/or the planar support. 5. The conductive planar sheet according to claim 1, wherein the planar support is connected to the respective conjunction of the planar frame that is located diagonal to the conjunction at which the sheet tip is located.

6. The conductive planar sheet according to claim 1, wherein:

one of the links includes a cantilever member having first and second ends, the second end extending from the planar frame;

the resilient element includes first and second ends, the resilient element being connected to the cantilever member at the first end and the planar frame at the second end; and

the sheet tip being at a connection of the first end of the cantilever member and the first end of the resilient element. 7. The conductive planar sheet according to claim 6, wherein the resilient element has a loop-like configuration.

8. A probe assembly for probing a bond pad on a semiconductor wafer, comprising: a plurality of the conductive planar sheets according to claim 1 that are stacked to form a layered structure, the sheet tips being stacked to form a probe tip array;

a dielectric layer disposed between the respective adjacent conductive planar sheets to provide electrical isolation therebetween;

first and second end plates configured to sandwich the plurality of planar sheets; and

at least one mounting tube extending through the respective alignment openings of the conductive planar sheets to align the planar sheets.

9. The probe assembly according to claim 8, wherein the first and second end plates each include a probe guard configured to sandwich the probe tip array of the planar sheets, the probe tip array extends beyond the probe guards, and the probe guards are configured to protect the probe tip array when the probe tip array is overdriven.

10. The probe assembly according to claim 9, further comprising:

a probe-tip template configured to maintain an alignment of the probe tips.

11. A method of producing the probe assembly according to claim 8, comprising: forming an imaged pattern for the planar sheets via a photo imaging process; forming the conductive planar sheets via the imaged pattern;

providing the dielectric layer on a surface of the planar sheets to provide electrical isolation between adjacent conductive planar sheets;

aligning and packing the planar sheets to form the layered structure;

sandwiching the layered structure via the end plates; and

pressing the end plates to compress the dielectric layer.

12. The method according to claim 11, further comprising expanding the mounting tubes to further align and secure the conductive planar sheets so as to provide a mechanical spacing and an electrical isolation between the respective adjacent conductive planar sheets.

Description:
MICROELECTROMECHANICAL SYSTEM (MEMS) BASED PROBE

FIELD

This disclosure relates generally to semiconductor test equipment. More particularly, the disclosure relates to a probe card including a stack of planar sheets forming a layered structure for probing a semiconductor device.

BACKGROUND

Existing probe cards for probing a semiconductor device on a semiconductor wafer include round probe wires that form an electrically conductive element, e.g., a probe needle, for contacting the semiconductor device. When probing a bond pad, a probe needle scrubs the surface of the bond pad to improve the contact between a probe tip thereof and the bond pad.

SUMMARY

Embodiments of this disclosure generally relate to a probe assembly. The probe assembly includes planar sheets that are stacked to form a layered structure. The probe assembly can be utilized to measure electric signals in semiconductor devices such as, but not limited to, electronic devices on a semiconductor wafer. The probe assembly can be, for example, a probe card, or a portion of a probe card.

Probe assemblies including a stack of planar sheets are provided. The planar sheets each have a planar, sheet structure and define a sheet tip thereof. The planar sheets are aligned and stacked to form a layered structure where the sheet tips are stacked to form a probe tip array. In some embodiments, a dielectric layer can be disposed between the respective adjacent planar sheets to provide mechanical spacing and electrical isolation therebetween.

The probe assemblies described herein can be formed by, for example, a Micro Electro Mechanical Systems (MEMS) process. A shape or pattern of a planar sheet thereof can be adjusted via a photo imaging process to optimize the performance of the probe assembly. This can provide superior geometric flexibility for producing probe assemblies in a cost-effective way. As the dimensions of semiconductor devices continue to shrink, many aspects of production become more difficult. The embodiments described herein provide probe cards that can have improved performance compared to conventional probe cards with a round probe wire for probing a bond pad on a semiconductor device when the dimension of the bond pad shrinks to, for example, a range below about 50 micrometers.

In one embodiment, a planar sheet includes a planar frame. The planar frame includes links connected to each other at respective conjunctions. A resilient element extends in a diagonal direction of the planar frame and connects an upper conjunction and a lower conjunction of the conjunctions. A sheet tip is defined at one of the conjunctions of the planar frame different from the upper and lower conjunctions. The planar frame has opposite ends and the sheet tip is located at one of the opposite ends. A planar support is connected to the other of the opposite ends of the planar frame.

In another embodiment, a planar sheet includes a planar frame and a resilient element. The resilient element can, for example, be a loop-like structure that is cantilevered from the planar frame via a cantilever member. A sheet tip is located at the conjunction of the cantilever member and the resilient element. The resilient element can exhibit a specific stiffness by adjusting a geometrical shape thereof so as to control, for example, a contact pressure the sheet tip can exert on a wafer pad. It will be appreciated that adjusting the geometrical shape of the resilient element can include varying thickness of the material, dimensions of the loop-like structure, varying dimensions of the cantilever member, or the like.

In another embodiment, a probe assembly for probing a bond pad on a

semiconductor wafer is provided. The planar sheets according to the above embodiment are stacked to form a layered structure. A dielectric layer is disposed between the respective adjacent planar sheets to provide mechanical spacing and electrical isolation therebetween. First and second end plates can sandwich the planar sheets. At least one mounting tube can extend through alignment openings of the planar sheets to align and support the planar sheets. The alignment openings can include one or more rigid and one or more flexible features to provide a kinematic mount for the probe assembly. In some embodiments, the alignment openings include one or more contact surfaces. In another embedment, a method of producing a probe assembly includes forming an imaged pattern for planar sheets via a photo imaging process, forming the planar sheets via the imaged pattern, providing at least one dielectric layer on a surface of the planar sheets to provide mechanical spacing and electrical isolation between adjacent conductive planar sheets, aligning and packing the planar sheets to form a layered structure, sandwiching the layered structure via the end plates, pressing the end plates to compress the dielectric layer, and expanding mounting tubes to fine-align and secure the planar sheets so as to provide a mechanical spacing and an electrical isolation between the respective adjacent planar sheets.

In another embodiment, a planar sheet is disclosed. The planar sheet includes a planar frame; a cantilever member having first and second ends, the second end extending from the planar frame; a resilient element having first and second ends and being connected to the cantilever member at the first end and the planar frame at the second end; and a sheet tip defined at connection of the first end of the cantilever member and the first end of the resilient element.

In one embodiment, a conductive planar sheet for a probe is disclosed. The planar sheet includes a planar frame including links connected to each other at respective conjunctions; a resilient element connected to the planar frame; and a sheet tip connected to the planar frame. The planar frame includes opposite ends, the sheet tip being located at one of the opposite ends and the resilient element being configurable to modify a contact pressure of the sheet tip.

In one embodiment, one of the links forming the planar frame includes a cantilever member. In such an embodiment, the cantilever member can be connected to the resilient element.

In one embodiment, the resilient element is configured to be modifiable such that a contact pressure of the sheet tip is variable based on a design of the resilient element.

BRIEF DESCRIPTION OF THE DRAWINGS

References are made to the accompanying drawings that form a part of this disclosure, and which illustrate the embodiments in which the systems and methods described in this specification can be practiced. FIG. 1 illustrates a cross-sectional perspective view of a probe card having a probe assembly that includes planar sheets, according to one embodiment.

FIG. 2 illustrates a side perspective view of a planar sheet, according to one embodiment.

FIG. 3 illustrates a right side perspective view of a planar sheet, according to one embodiment.

FIG. 4 illustrates a left side perspective view of the planar sheet of FIG. 3.

FIG. 5 illustrates a side perspective view of a probe assembly, according to one embodiment.

FIG. 6A illustrates a side perspective view of a probe assembly, according to another embodiment.

FIG. 6B illustrates an enlarged portion view of the probe assembly of FIG. 6A. FIG. 6C illustrates a side exploded view of the probe assembly of FIG. 6A.

FIG. 7 illustrates a cross-sectional perspective view of a probe card having a probe assembly that includes planar sheets, according to another embodiment.

FIG. 8 illustrates an assembly perspective view of the probe assembly of FIG. 7, according to one embodiment.

FIG. 9A illustrates a side perspective view of the probe card of FIG. 7, according to one embodiment.

FIG. 9B illustrates an enlarged portion of the view of the probe card of FIG. 9A.

Like reference numbers represent like parts throughout.

DETAILED DESCRIPTION

Embodiments described herein generally relate to a probe assembly. The probe assembly includes planar sheets that are stacked to form a layered structure. The probe assembly can be utilized to measure electric signals in semiconductor devices, for example, electronic devices on a semiconductor wafer. The probe assembly can be, for example, a probe card, or a portion of a probe card.

Probe assemblies including a stack of planar sheets, are provided. The planar sheets each have a planar, sheet structure and define a sheet tip thereof. The planar sheets are aligned and stacked to form a layered structure. In some embodiments, a dielectric layer can be disposed between the respective adjacent planar sheets to provide mechanical spacing and electrical isolation therebetween.

The probe assemblies described herein can be formed by, for example, a Micro Electro Mechanical Systems (MEMS) process. A shape or pattern of a planar sheet thereof can be adjusted via a photo imaging process to optimize the performance of the probe assembly. This can provide superior geometric flexibility for producing probe assemblies in a cost-effective way.

In one embodiment, the planar sheets can include a planar frame including links connected to each other at respective conjunctions; a resilient element connected to the planar frame; and a sheet tip connected to the planar frame. The planar frame includes opposite ends, the sheet tip being located at one of the opposite ends.

FIG. 1 illustrates a probe card 100, according to one embodiment. The probe card 100 includes a probe tile 120, and probes 110a, 110b that are mounted to the probe tile 120. The probes 110a, 110b include respective probe tips 112a, 112b that are arranged, for example, side -by-side. The probes 110a, 110b can be formed by aligning and stacking planar sheets via respective alignment tubes 160a, 160b to form a layered structure, and sandwiching the layered structure via end plates such as, for example, end plates 530 shown in FIG. 5. In one embodiment, the probes 110a, 110b can each be a probe 50 shown in FIG. 5 and discussed in additional detail below. It is to be understood that other numbers of probes can be mounted to the probe tile 120.

The probe tile 120 has a central opening 122 and the probe tips 112a, 112b of the probes 110a, 110b extend out of the central opening 122 so as to, for example, make a physical contact with a bond pad on a semiconductor wafer. The probes 110a, 110b each include contacts 114 electrically connected to the respective probe tips 112a, 112b. The contacts 114 can be, for example, signal contacts.

The probe card 100 includes a circuit card 130 connected to the probe tile 120 and configured to electrically connect the probes 110a, 110b to a probe card interface 140. The probe card interface 140 includes connecting wires 141 supported by a wire guide 144. The connecting wires 141 electrically connect to the contacts 114 of the probes 110a, 110b via the circuit card 130 at one end, and connect to a detecting device (not shown) at another end. In some embodiments, the connecting wires 141 can be directly connected to the probes 110a, 110b.

FIG. 2 illustrates a planar sheet 20, according to one embodiment. The planar sheet 20 has a planar, sheet structure that extends in an X-Y plane. In some embodiments, the planar sheet 20 can have dimensions in the X-Y plane of several millimeters by several millimeters, and a thickness of about 0.005 to about 0.05 millimeters. In one embodiment, the planar sheet 20 can have a length of about 7.8 mm and a width of about 3.7 mm in the X-Y plane, and a thickness of about 0.012 to about 0.02 mm or lower than about 0.012 mm.

In one embodiment, the planar sheet 20 can include a planar frame 210 including links 21, 22, 23, and 24 connected to each other at conjunctions; a resilient element 25 connected to the planar frame 210; and a sheet tip 26 connected to the planar frame 210. The planar frame 210 includes opposite ends, the sheet tip 26 being located at one of the opposite ends.

The planar sheet 20 includes the planar frame 210 and a planar support 220 connected to each other.

The planar frame 210 is formed by connecting links 21, 22, 23, and 24. The links 21, 22, 23, and 24 can be, for example, planar bars, and the planar frame 210 can form a four-bar mechanism by connecting the planar bars. The links 21, 22, 23, and 24 of the planar frame 210 define an opening 25'. The resilient element 25 extends across the opening 25' in a diagonal direction of the planar frame 210 and connects an upper conjunction 212 that connects the links 21 and 22 and a lower conjunction 234 that connects the links 23 and 24. The resilient element 25 can be, for example, a spring element. The sheet tip 26 is defined at a conjunction 214 that connects the links 21 and 24 and extends along an X-axis. In the embodiment shown in FIG. 2, the sheet tip 26 is located at the conjunction 214 that is not connected to the resilient element 25. It will be appreciated that the sheet tip 26 can be located at a conjunction connected to a resilient element. The resilient element 25 can exhibit a specific stiffness by adjusting a geometrical shape thereof so as to control, for example, a contact pressure the sheet tip 26 can exert on a wafer pad. The planar support 220 extends in a direction along the Y-axis and connects to the link 23 of the frame 210 adjacent a conjunction 223 that connects the links 22 and 23. The conjunctions 223 and 214 are arranged along a diagonal direction of the planar frame 210. In some embodiments, the link 22 is tilted toward the sheet tip 26 and forms an angle a with respect to the Y-axis.

Alignment openings 240 are defined on the link 23 and arranged along the X-axis. A contact 250 connects to the planar support 220 and extends in a direction, for example, opposite to the direction of the probe tip 26 along the X-axis. The contact 250 can be, for example, a signal contact. It will be appreciated that the alignment openings 240 can be located on the planar support 220. In some embodiments, the alignment openings 240 can be aligned along the Y-axis or other directions. The alignment openings 240 can be, for example, through holes.

The planar sheet 20 is made of a conductive material, for example, a metallic sheet. The metallic sheet can be, for example, a beryllium copper or tungsten sheet. It is to be understood that a portion of the planar sheet 20 can be non-conductive as long as the contact 250 and the probe tip 26 are electrically connected.

In some embodiments, the planar sheet 20 can be formed by a Micro Electro Mechanical Systems (MEMS) process as a single unit. The MEMS process can form a geometry of an imaged pattern for a planar sheet such as, for example, the planar sheet 20, via a photo imaging process. The photo imaging process is known in the art and can provide mass production with high levels of repeatability. The performance of a planar sheet can be optimized by adjusting the geometry of the imaged pattern. A MEMS process of using photolithography to create structures in small dimensions (e.g., micrometers to millimeters) is known.

FIGS. 3 and 4 illustrate a planar sheet 30, according to another embodiment. The planar sheet 30 has a planar, sheet structure that extends in an X-Y plane and includes a first side 301 and a second, opposite side 302. The planar sheet 30 can be made of a conductive material, for example, a beryllium copper or tungsten sheet. In some embodiments, the planar sheet 30 can be formed by a MEMS process discussed above. The planar sheet 30 includes a planar frame 310 and a planar support 320 connected to each other. The planar frame 310 includes a resilient element 325 and a sheet tip 326. In some embodiments, a thin dielectric layer 330 is disposed on the side 301 of the planar sheet 30 to provide an electrical isolation. The thin dielectric layer 330 can have a thickness of, for example, about 10 micrometers to about 30 micrometers.

Alignment openings 340 are defined on the planar support 320 and are arranged along the Y-axis. As shown in FIG. 3, the thin dielectric layer 330 is disposed on a majority portion of the frame 310 and spaces around the alignment openings 340 on the planar support 320.

In some embodiments, a crushable dielectric layer 350 is disposed on the side 302 along a periphery of the alignment openings 340 to provide spacing and electrical isolation. The thickness of the crushable dielectric layer 350 can be greater than that of the thin dielectric layer 330. The crushable dielectric layer 350 can be compressed along a thickness direction thereof. In some embodiments, the crushable dielectric layer 350 can be compressed to reduce from a first thickness to a second thickness.

In some embodiments, the thin dielectric layer 330 and the crushable dielectric layer 350 can be directly patterned on the sides 301 and 302 by a MEMS process. It will be appreciated that the thin dielectric layer 330 and the crushable dielectric layer 350 can be respectively formed on opposite sides of the planar sheet 20 in a similar manner as on the planar sheet 30. It will also be appreciated that the thin dielectric layer 330 and the crushable dielectric layer 350 can be separate layer(s) that can be sandwiched by adjacent planar sheets when two or more planar sheets are stacked along a Z-axis that is perpendicular to the X-Y plane.

FIG. 5 illustrates a probe assembly 50 that includes a stack of planar sheets 510. The stack of the planar sheets 510 can be formed by, for example, stacking two or more planar sheets such as, for example, the planar sheets 20 or 30 of FIGS. 2 - 4 along a Z- axis that is perpendicular to an X-Y plane. The planar sheets 510 are aligned by extending mounting tubes 520 along the Z axis through respective alignment openings of the planar sheets 510 such as, for example, the alignment openings 240 and 340 shown in FIGS. 2 - 4. The respective adjacent planar sheets 510 are separated and electrically isolated by a dielectric layer such as, for example, the thin dielectric layer 330, and/or the crushable dielectric layer 350 shown in FIGS. 3 - 4. The planar sheets 510 each can include a sheet tip such as the sheet tips 26 and 326 shown in FIGS. 2 - 4. When the planar sheets 510 are aligned and stacked to form a layered structure, the sheet tips of the planar sheets 510 are stacked to form a layered structure of a probe tip array 512.

The stack of planar sheets 510 is sandwiched and contained by end plates 530 at opposite sides of the planar sheets 510. The end plates 530 extend in the X-Y plane and can have a thickness of, for example, about 0.5 mm to about 1 mm. The end plates 530 each have respective mounting openings 522 corresponding to the alignment openings of the planar sheets 510. The mounting tubes 520 extend through the mounting openings 522 and the alignment openings of the planar sheets 510 to align and mount the planar sheets 510 with the end plates 530. The end plates 530 can be made of a rigid material that can provide lateral stiffness to the probe assembly 50 and can prevent physical damage to the planar sheets 510.

In some embodiments, the end plates 530 include probe guards 532 that sandwich the probe tip array 512 of the planar sheets 510. The probe tip array 512 can extend beyond the probe guards 532 in a direction along the X-axis with a distance d about 100 micrometers. In some embodiments, the distance d can be, for example, about 50 micrometers to about 200 micrometers, and in some cases more than 200 micrometers. When the probe tip array 512 contacts an object such as, for example, a bond pad on a semiconductor wafer, the probe tip array 512 can be deflected. When the probe tip array 512 is deflected with the distance d, the probe guards 532 can rest on the object and protect the probe tip array 512 from over-deflection. In this way, when the probe tip array 512 is overdriven, additional deflection loads on the probe tip array 512 can be resolved through the end plates 530 and the mounting tubes 520 so that the probe tip array 512 can be protected.

In some embodiments, contacts 514 of the planar sheets 510 extend out of the end plates 530. The contacts 514 are staggered and fanned as shown in FIG. 5 to be connected to a circuit card such as, for example, the circuit card 130 of FIG. 1. The contacts 514 can be separated from each other by the circuit card 130 or by adding an insulating sleeve therebetween. During assembly of the probe assembly 50, a pressure can be applied to the end plates 530 at opposite directions along the Z-axis as shown by arrows al and a2. The pressure can compress a dielectric layer such as, for example, the crushable dielectric layer 350 between adjacent planar sheets 510, to achieve a desired thickness. As shown in FIGS. 3 and 4, the first side 301 and the second side 302 of the respective adjacent planar sheets can face each other and be compressed to connect with each other. In some embodiments, the crushable dielectric layer 350 and the think dielectric layer 330 of the respective adjacent planar sheets may not overlap with each other. After the assembly, the crushable dielectric layer 350 can be thicker than the thin dielectric layer 330 so that the overall thickness of the stack of planar sheets 510 can be determined by the thickness of the crushable dielectric layer 350. The crushable dielectric layer 350 can provide mechanical spacing and electrical isolation between the respective adjacent planar sheets 510. The thin dielectric layer 330 can prevent possible physical contacts between the respective adjacent planar sheets 510. In the meantime, a clearance between adjacent planar sheets can be provided to allow each of the planar sheets 510 to flex

independently.

The mounting tubes 520 can be expandable. In one embodiment, the mounting tubes 520 can be made of a non-conductive material such as, for example, glass or other expandable materials. One or more of the mounting tubes 520 that extend through the alignment openings of the planar sheets 510 can be expanded to further align the planar sheets 510 such that the spacing between the respective adjacent planar sheets 510 can be maintained. In some embodiments, the mounting tubes 520 can be heated by, for example, a resistance wire that is disposed in the center of the mounting tubes 520. Then an air pressure can be applied to expand the mounting tubes 520. After cooling the mounting tubes 520, the planar sheets 510 can be fixed and tightened on the mounting tubes 520.

A dielectric layer such as, for example, the crushable dielectric layer 350 and/or the thin dielectric layer 330, between the adjacent planar sheets can be made of a dielectric material that has a compressive yield far below the tensile yield of the mounting tubes 520. This allows a possible thermal expansion of the material of the mounting tubes 520 to dominate a thermal error. In some embodiments, the material of the mounting tubes 520 can have a lower expansion coefficient than that of the dielectric material of the dielectric layer.

In some embodiments, a wafer to be probed by a probe assembly such as, for example, the probe assembly 50, can have an expansion coefficient of, for example, about 4 parts per million (PPM) per 0 C. The probe assembly 50 can be at a lower temperature when the probe assembly 50 sits above the wafer, for example, about 50 0 C lower than that of the wafer. The probe assembly 50 can have an expansion coefficient slightly larger than that of the wafer. The expansion coefficient of the probe assembly 50 can be, for example, about 6 PPM per 0 C. The higher expansion coefficient of the probe assembly 50 can compensate the lower temperature thereof to produce a total expansion of the probe assembly that can match the wafer.

FIGS. 6A - 6C illustrate a probe assembly 60, according to another embodiment. The probe assembly 60 includes a stack of planar sheets 610 that are sandwiched and contained by end plates 630 at opposite sides of the planar sheets 610 to form a layered structure. Mounting tubes 620 extend through respective alignment openings of the end plates 630 and the planar sheets 610 to align and secure the end plates 630 and the planar sheets 610. The end plates 630 each have an opening 634 through which a portion of the planar sheets 610, for example, resilient elements 615 that are aligned to be a layered structure, can be observed. The opening 634 can be an access hole that allows for visual inspection of the resilient elements 615. In some embodiments, when one of the planar sheets 610 is too stiff or out of position, the respective resilient element can be manipulated to adjust the shape or position of the planar sheet.

The end plates 630 include probe guards 632 that sandwich a probe tip array 612 of the stack of planar sheets 610 to protect the probe tip array 612 from an overdrive. The probe tip array 612 can extend beyond an edge of the probe guards 632 with a distance of, for example, about 100 micrometers.

The planar sheets 610 include contacts 614 that are staggered and fanned as groups 614a - 614d, as shown in FIG. 6C. The respective adjacent contacts such as, for example, al, bl, and cl, are positioned with an offset dl or d2. In this manner, the contacts 614 can be respectively aligned and grouped into the groups 614a - 614d. FIG. 7 illustrates a cross-sectional perspective view of a probe card 100 having a probe assembly that includes planar sheets, according to another embodiment. Aspects of FIG. 7 can be the same as or similar to aspects of FIGS. 1 - 6. For the simplicity of this specification, aspects which have been previously described will not be described in additional detail.

The probe card 100 includes a probe tile 120 and probes 110c, 1 lOd that are mounted to the probe tile 120. The probes 110c, 1 lOd include respective probe tips 112c, 112d that are arranged, for example, side -by-side. The probes 110c, 1 lOd can be formed by aligning and stacking planar sheets via respective alignment tubes 160a, 160b to form a layered structure. In one embodiment, the layered structure can be sandwiched via end plates. In one embodiment, the probes 110c, 1 lOd can each be a probe assembly 800 shown in FIG. 8 and discussed in additional detail below. It is to be understood that other numbers of probes can be mounted to the probe tile 120. In one embodiment, the probe card 100 can include one or more additional features such as, but not limited to, a circuit card (e.g., circuit card 130 as shown in FIG. 1), a probe card interface (e.g., probe card interface 140 including connecting wires 141 and wire guide 144 as shown in FIG. 1), or the like.

FIG. 8 illustrates an assembly perspective view of the probe assembly 800 of FIG. 7, according to one embodiment. The probe assembly 800 includes a plurality of planar sheets 801. The planar sheets 801 have a planar, sheet structure that extends in an X-Y plane. In some embodiments, the planar sheet 801 has the same or similar dimensions as the planar sheet 20 (FIG. 2).

In one embodiment, the planar sheet 801 can include a planar frame 803 including links 803a, 803b, 803c, 803d connected to each other at conjunctions; a resilient element 808 connected to the planar frame; and a sheet tip 810 connected to the planar frame. The planar frame 803 includes opposite ends, the sheet tip 810 being located at one of the opposite ends. The planar sheet 801 includes a planar frame 803 and a planar support 805 connected to each other. The planar frame 803 is formed by connecting links 803a, 803b, 803c, and 803d. The links 803a, 803b, 803c, and 803d can be, for example, planar bars, and the planar frame 803 can form a four-bar mechanism by connecting the planar bars. In one embodiment, a cantilever member 809 is part of one of the links 803c or 803d. In one embodiment, the cantilever member 809 can be connected to a portion of the planar support 805. In one embodiment, the cantilever member 809 has a relatively longer length than the planar frame 803 with reference to extension from the planar support 805. The link 803c includes a space A maintained between the cantilever member 809 of the link 803c and the portion of the link 803c connected to the other links (e.g., 803b and 803d), with the space A being configured based on a desired stiffness of the cantilever member 809 and the resilient element 808.

The planar sheet 801 includes the resilient element 808 and a sheet tip 810. The resilient element 808 can, for example, be a spring. The resilient element 808 can include a portion 808a and a portion 808b. A space 813 may be disposed between the portion 808a and the portion 808b, with the portion 808b being disposed relatively nearer to the planar frame 803 than the portion 808a. In one embodiment, the resilient element 808 can be a loop-like structure that is cantilevered from the planar frame 803 via cantilever member 809. In one embodiment, a configuration of the resilient element can be optimized using finite element analysis. The sheet tip 810 is located at the conjunction of the cantilever member 809 and the resilient element 808. The resilient element 808 can exhibit a specific stiffness by adjusting a geometrical shape thereof so as to control, for example, a contact pressure the sheet tip 810 can exert on a wafer pad. A portion 814 at the conjunction of the cantilever member 809 and the resilient element 808 can be larger than the resilient element 808 and/or the cantilever member 809. For example, in the illustrated embodiment the portion 814 has a greater planar area than that of the resilient element 808 and the cantilever member 809 at about the location of the conjunctions with the portion 814. This can be modified, for example, to alter the contact pressure the sheet tip 810 can exert on a wafer pad. It will be appreciated that adjusting the geometrical shape of the resilient element 808 can include varying thickness of the material, dimensions of the loop-like structure, varying dimensions of the cantilever member 809, or the like. A space 812 can be maintained between the resilient element 808 and the planar frame 803 such that the resilient element 808 is deflectable in response to an applied force. The configuration of the space 812 can be selected based upon the geometry of the portion 808b of the resilient element 808. For example, the space 812 can be selected such that when a force is applied to the sheet tip 810 and the resilient element 808 deflects in a direction R, the portion 808b of the resilient element 808 does not come into contact with the planar frame 803. In another embodiment, the space 812 can be selected such that when a force is applied to the sheet tip 810 and the resilient element 808 deflects in the direction R, the portion 808b of the resilient element 808 does come into contact with the planar frame 803, and the planar frame 803 serves to limit the movement of the resilient element 808. A space B between the portion 808a and the portion 808b of the resilient element 808 can be configured based on a desired stiffness of the resilient element 808.

The planar sheet 801 is made of a conductive material, for example, a metallic sheet. The metallic sheet can be, for example, a beryllium copper or tungsten sheet. It is to be understood that a portion of the planar sheet 801 can be non-conductive as long as the contact 114 and the sheet tip 810 are electrically connected.

In some embodiments, the planar sheet 801 can be formed by a Micro Electro Mechanical Systems (MEMS) process as a single unit. The MEMS process can form a geometry of an imaged pattern for a planar sheet such as, for example, the planar sheet 801, via a photo imaging process. The photo imaging process is known in the art and can provide mass production with high levels of repeatability. The performance of a planar sheet can be optimized by adjusting the geometry of the imaged pattern. A MEMS process of using photolithography to create structures in small dimensions (e.g., micrometers to millimeters) is known.

The probe assembly 800 includes an alternating formation of the planar sheet 801 and a dielectric layer 802. In one embodiment, the dielectric layer 802 can be the same as or similar to the crushable dielectric layer 350 (FIG. 3) and/or the thin dielectric layer 330 (FIG. 3). The dielectric layer 802 can be compressed along a thickness direction thereof. In some embodiments, the dielectric layer 802 can be compressed to reduce from a first thickness to a second thickness. In general, the dielectric layer 802 can provide spacing and electrical isolation between the planar sheets 801.

The planar sheet 801 includes alignment openings 804 and 806 configured to receive the alignment tubes 160a or 160b. The alignment openings 804 and 806 are generally circular. The alignment opening 804 includes contact surfaces 804a, 804b and the alignment opening 806 includes contact surfaces 806a - 806c. The contact surfaces 804a - 804b and 806a - 806c are configured to provide a contact surface for the alignment tubes 160a/160b. The contact surfaces 804a - 804b and 806a - 806c constrain the planar sheet 801 to prevent unwanted movement of the probe assembly 800 when installed in the probe card 120 (FIG. 7) and/or during test. The contact surface 804a - 804b and 806a - 806c provide a kinematic mount for the probe assembly 800.

FIG. 9A illustrates a side perspective view of the probe card 120 of FIG. 7, according to one embodiment. FIG. 9B illustrates an enlarged portion of the view of the probe card of FIG. 9 A. The probe card 120 includes probes 110 and probe tips 112. The illustrated embodiment also includes a probe tip template 902. The probe tip template 902 can maintain the probe tips 112 in a desired location. In one embodiment, this can, for example, maintain the probe tips in a desired location with respect to a device under test. The probe tip template can be, for example, a non-conductive layer configured selected to withstand the thermal conditions of semiconductor testing. In one embodiment, the probe tip template 902 is a polyimide film.

Aspects:

It is to be appreciated that any of aspects 1 - 5 can be combined with any of aspects 6 - 8, 9 - 13, 14 - 15, 16, or 17. Any of aspects 6 - 8 can be combined with any of aspects 9 - 13, 14 - 15, 16, or 17. Any of aspects 9 - 13 can be combined with any of aspects 14 - 15, 16, or 17. Any of aspects 14 - 15 can be combined with any of aspects 16 or 17. Aspect 16 can be combined with aspect 17.

Aspect 1. A planar sheet, comprising:

a planar frame including links connected to each other at respective conjunctions, a resilient element extending in a diagonal direction of the planar frame and connecting an upper conjunction and a lower conjunction of the conjunctions, a sheet tip defined at one of the conjunctions of the planar frame different from the upper and lower conjunctions, the planar frame having opposite ends and the sheet tip being located at one of the opposite ends; and

a planar support connected to the other of the opposite ends of the planar frame. Aspect 2. The planar sheet according to aspect 1, further comprising one or more contacts electrically connected to the sheet tip.

Aspect 3. The planar sheet according to any of aspects 1 - 2, further comprising at least one alignment opening on the planar frame and/or the planar support.

Aspect 4. The planar sheet according to any of aspects 1 - 3, wherein the planar support is connected to the respective conjunction of the planar frame that is located diagonal to the conjunction at which the sheet tip is located

Aspect 5. The planar sheet according to any of aspects 1 - 4, wherein the planar sheet is made of a conductive material.

Aspect 6. A probe assembly for probing a bond pad on a semiconductor wafer, comprising:

a plurality of the planar sheets according to claim 3 that are stacked to form a layered structure, the sheet tips being stacked to form a probe tip array;

a dielectric layer disposed between the respective adjacent planar sheets to provide electrical isolation therebetween;

first and second end plates configured to sandwich the plurality of planar sheets; and

at least one mounting tube extending through the respective alignment openings of the planar sheets to align the planar sheets. Aspect 7. The probe assembly according to aspect 5, wherein the first and second end plates each include a probe guard configured to sandwich the probe tip array of the planar sheets, the probe tip array extends beyond the probe guards, and the probe guards are configured to protect the probe tip array when the probe tip array is overdriven. Aspect 8. A method of producing the probe assembly according to aspect 5, comprising:

forming an imaged pattern for the planar sheets via a photo imaging process; forming the planar sheets via the imaged pattern;

providing the dielectric layer on a surface of the planar sheets to provide electrical isolation between adjacent conductive planar sheets;

aligning and packing the planar sheets to form the layered structure;

sandwiching the layered structure via the end plates;

pressing the end plates to compress the dielectric layer; and

expanding the mounting tubes to further align and secure the planar sheets so as to provide a mechanical spacing and an electrical isolation between the respective adjacent planar sheets.

Aspect 9. A planar sheet, comprising:

a planar frame;

a cantilever member having first and second ends, the second end extending from the planar frame;

a resilient element having first and second ends and being connected to the cantilever member at the first end and the planar frame at the second end; and

a sheet tip defined at connection of the first end of the cantilever member and the first end of the resilient element.

Aspect 10. The planar sheet according to aspect 9, further comprising one or more contacts electrically connected to the sheet tip.

Aspect 11. The planar sheet according to any of aspects 9 - 10, further comprising at least one alignment opening on the planar frame.

Aspect 12. The planar sheet according to any of aspects 9 - 11, wherein the resilient element has a loop-like configuration. Aspect 13. The planar sheet according to any of aspects 9 - 12, wherein the planar sheet is made of a conductive material.

Aspect 14. A probe assembly for probing a bond pad on a semiconductor wafer, comprising:

a plurality of the planar sheets according to aspect 9 that are stacked to form a layered structure, the sheet tips being stacked to form a probe tip array;

a dielectric layer disposed between the respective adjacent planar sheets to provide electrical isolation therebetween;

first and second end plates configured to sandwich the plurality of planar sheets; and

at least one mounting tube extending through the respective alignment openings of the planar sheets to align the planar sheets. Aspect 15. The probe assembly according to aspect 13, further comprising:

a probe-tip template configured to maintain an alignment of the probe tips.

Aspect 16. A method of producing the probe assembly according to aspect 13, comprising:

forming an imaged pattern for the planar sheets via a photo imaging process; forming the planar sheets via the imaged pattern;

providing the dielectric layer on a surface of the planar sheets to provide electrical isolation between adjacent conductive planar sheets;

aligning and packing the planar sheets to form the layered structure;

sandwiching the layered structure via the end plates;

pressing the end plates to compress the dielectric layer; and

expanding the mounting tubes to further align and secure the planar sheets so as to provide a mechanical spacing and an electrical isolation between the respective adjacent planar sheets. Aspect 17. A planar sheet, comprising:

a planar frame including links connected to each other at respective conjunctions; a resilient element connected to the planar frame; and

a sheet tip connected to the planar frame,

the planar frame having opposite ends and the sheet tip being located at one of the opposite ends.

The examples disclosed in this application are to be considered in all respects as illustrative and not limitative. The scope of the invention is indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.

The terminology used in this specification is intended to describe particular embodiments and is not intended to be limiting. The terms "a," "an," and "the" include the plural forms as well, unless clearly indicated otherwise. The terms "comprises" and/or "comprising," when used in this Specification, specify the presence of the stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or components.

With regard to the preceding description, it is to be understood that changes may be made in detail, especially in matters of the construction materials employed and the shape, size, and arrangement of parts without departing from the scope of the present disclosure. This Specification and the embodiments described are exemplary only, with the true scope and spirit of the disclosure being indicated by the claims that follow.