DISTRIBUTION

BACKGROUND

Field

[0001] Embodiments of the present disclosure generally relate to an apparatus for processing large area substrates. More particularly, embodiments of the present disclosure relate to a process kit positioned between a cathode and the substrate in an atomic layer deposition (ALD) chamber.

Description of the Related Art

[0002] ALD is based upon atomic layer epitaxy (ALE) and employs chemisorption techniques to deliver precursor molecules on a substrate surface in sequential cycles. The cycle exposes the substrate surface to a first precursor and then to a second precursor. Optionally, a purge gas may be introduced between introductions of the precursors. The first and second precursors react to form a product compound as a film on the substrate surface. The cycle is repeated to form the layer to a predetermined thickness. In a cross flow ALD chamber, precursors and purge gasses, also known as process gasses, flow from an inlet located at one side of the chamber to an outlet located at an opposite side of the chamber. The process gases flow across a processing region located between the inlet and the outlet.

[0003] However, process gases may not be uniformly distributed across the processing region, and thus may not be uniformly distributed across the substrate. Therefore, the thickness profile of the film formed on the substrate may not be uniform.

[0004] Accordingly, an improved ALD chamber is needed.

SUMMARY

[0005] Embodiments of the present disclosure generally relate to a new process kit for use in an ALD chamber and to process chambers having the new process kit. In one embodiment, the new process kit includes a mask frame including a first side having a first manifold in fluid communication with a first plurality of channels and a second side opposite the first side. The second side includes a second manifold in fluid communication with a second plurality of channels. The mask frame further includes a third side connecting the first side and the second side, and the third side includes a third manifold in fluid communication with the third plurality of channels. The third manifold is in fluid communication with the second manifold. The mask frame further includes a fourth side opposite the third side, and the fourth side includes a fourth manifold in fluid communication with a fourth plurality of channels. The fourth manifold is in fluid communication with the second manifold.

[0006] In another embodiment, a process kit includes a dielectric window, a sealing frame, and a mask frame coupled to the dielectric window by the sealing frame. The mask frame includes a first side having a first manifold in fluid communication with a first plurality of channels and a second side opposite the first side. The second side includes a second manifold in fluid communication with a second plurality of channels. The mask frame further includes a third side connecting the first side and the second side, and the third side includes a third manifold in fluid communication with the third plurality of channels. The third manifold is in fluid communication with the second manifold. The mask frame further includes a fourth side opposite the third side, and the fourth side includes a fourth manifold in fluid communication with a fourth plurality of channels. The fourth manifold is in fluid communication with the second manifold.

[0007] In another embodiment, a processing chamber includes a chamber body, a substrate support assembly at least partially disposed within the chamber body, and a process kit. The process kit includes a dielectric window, a sealing frame, and a mask frame coupled to the dielectric window by the sealing frame. The mask frame includes a first side, a second side opposite the first side, a third side connecting the first side and the second side, and a fourth side opposite the third side, the mask frame being configured to allow a gas to flow from the first side to the second side, at least a portion of the third side, and at least a portion of the fourth side. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

[0009] Figure 1 illustrates an exemplary processing system, according to one embodiment described herein.

[0010] Figure 2 is a partial cross sectional side view showing an illustrative ALD processing chamber, according to one embodiment described herein.

[0011] Figures 3A-3D are various views of a process kit, according to one embodiment described herein.

[0012] Figure 4A is a prospective view of a mask frame of the process kit of Figure 3A, according to one embodiment described herein.

[0013] Figure 4B is a partial cross-sectional view of the mask frame of Figure 4A, according to one embodiment described herein.

[0014] Figures 5A - 5B are schematic top views showing gas flow across a substrate.

[0015] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.

DETAILED DESCRIPTION

[0016] Embodiments of the present disclosure include a process kit to be used in an ALD processing chamber. The process kit includes mask frame having a first side, a second side opposite the first side, a third side connecting the first side and the second side, and a fourth side opposite the third side further connecting the first side and the second side. The first side includes a first manifold connected to a first plurality of channels, the second side includes a second manifold connected to a second plurality of channels, the third side includes a third manifold connected to a third plurality of channels, and the fourth side includes a fourth manifold connected to a fourth plurality of channels. The third and fourth manifolds are both in fluid communication with the second manifold. Each of the third and fourth manifolds extends about 20 to about 100 percent of the length of the third and fourth sides, respectively. The mask frame facilitates side pumping in the ALD processing chamber, which leads to improved thickness uniformity of a layer formed in the ALD processing chamber.

[0017] As used herein, a substrate is not limited to any particular size or shape. In one aspect, the term “substrate” refers to any polygonal, squared, rectangular, curved or otherwise non-circular workpiece, such as a glass or polymer substrate used in the fabrication of flat panel displays, for example.

[0018] In the description that follows, the terms“gas” and“gases” are used interchangeably, unless otherwise noted, and refer to one or more precursors, reactants, catalysts, carrier gases, purge gases, cleaning gases, effluent, combinations thereof, as well as any other fluid.

[0019] Figure 1 is an exemplary illustration of a processing system 100, according to one embodiment of the present disclosure. An exemplary substrate 102 is shown adjacent to the processing system 100. The processing system 100 includes a load-lock chamber 104, a transfer chamber 106, a first processing chamber 1 10, a second processing chamber 1 12, a third processing chamber 1 14, a fourth processing chamber 1 16, and a mask chamber 1 18. The load-lock chamber 104, the first, second, third, and fourth processing chambers 1 10, 1 12, 1 14, 1 16, and the mask chamber 1 18 are coupled to the transfer chamber 106. A transfer robot 108 is disposed in the transfer chamber 106 for transferring the substrate 102 into and out of the load-lock chamber 104 and the processing chambers 1 10, 1 12, 1 14, and 1 16. In one embodiment, the processing system 100 is operable to deposit an encapsulation layer on an optical device, such as an organic light emitting diode (OLED). The encapsulation layer may be a multi layer structure including one or more dielectric layers, such as silicon nitride, silicon oxynitride, high K or any suitable dielectric layers. In one embodiment, the first, second, and third processing chambers 1 10, 1 12, and 1 14 are chemical vapor deposition (CVD) chambers, such as plasma-enhanced CVD (PECVD) chambers, and the fourth processing chamber 1 16 is an ALD chamber.

[0020] Masks, mask sheets, and other items placed within the processing chambers 1 10, 1 12, 1 14, and 1 16, other than substrates, may be referred to as a “process kit.” The transfer robot 108 facilitates the transfer of a process kit into and out of the processing chambers 1 10, 1 12, 1 14 and 1 16.

[0021] Figure 2 is a partial cross sectional side view showing an illustrative ALD processing chamber 200 with a process kit 202 according to embodiments described herein. The ALD processing chamber 200 shown in Figure 2 may be the same as the processing chamber 1 16 shown in Figure 1 . In one embodiment, the processing chamber 200 includes a chamber body 204, and a susceptor or substrate support assembly 208. The substrate support assembly 208 is at least partially disposed within the chamber body 204. The lid assembly 206 includes a process gas inlet 210 and a pumping port 212 to provide cross- flow through the process kit.

[0022] The chamber body 204 includes a slit valve opening 214 to provide access to the interior of the processing chamber 200. In one or more embodiments, the chamber body 204 includes one or more apertures 216 and 218 that are in fluid communication with a vacuum system 220. The vacuum system 220 includes a vacuum pump 222 and one or more valves 224 and 226. The aperture 216 provides an egress for gases within the processing chamber 200 while the aperture 218 provides a pathway for gases from the pumping port 212. The vacuum system 220 is controlled by a process controller to maintain a pressure within the processing chamber 200 suitable for the ALD process. The vacuum system 220 may be used to maintain a first pressure in an interior volume 228 of the processing chamber 200. The vacuum system 220 may also be used to maintain a second pressure within a volume 230 defined within the process kit 202 (described in greater detail below). In one embodiment of the present disclosure, the first pressure may be less than the second pressure.

[0023] The process kit 202 is movable within the interior volume 228 of the processing chamber 200. The process kit 202 includes at least a mask frame 232. The process kit 202 may also include a dielectric window 234 coupled to the mask frame 232. The lid assembly 206 includes a radio frequency (RF) cathode 236 that can generate a plasma of reactive species within the processing chamber 200 and/or within the process kit 202. The process kit 202 may be selectively raised and lowered by support members 238 to permit removal and replacement of the process kit. The support members 238 may also serve as alignment and/or positioning devices for the process kit 202. The substrate 102 is shown supported by lift pins 239 movably disposed in the substrate support assembly 208. The substrate 102 is shown in a transfer position in Figure 2 such that a robot handling blade (not shown) may access a surface of the substrate 102 opposing the substrate support assembly 208. In a processing position, the substrate 102 may be raised by the substrate support assembly 208 to a position adjacent to the process kit 202. Specifically, the substrate 102 is adapted to be in contact with, or in proximity to a mask sheet 241 , which is coupled to the mask frame 232.

[0024] As shown in Figure 2, the process kit 202 is urged by the support members 238 to contact a surface of the lid assembly 206 and/or position the dielectric window 234 in proximity to the RF cathode 236. Specifically, when the process kit 202 is urged against a lower surface of the lid assembly 206, a first manifold 242, or a gas inlet port, and a second manifold 244, or a gas outlet port, are coupled to the process gas inlet 210 and the pumping port 212, respectively. In this manner, the precursor gases may be provided to the process gas inlet 210 and to the volume 230 through the first manifold 242. The precursor gases may flow in the volume 230 across the substrate 102 to be exhausted through the second manifold 244 and the pumping port 212.

[0025] Film properties, such as film stress, may be controlled by controlling one or more variables within the processing chamber 200. In one embodiment, film stress can be controlled by controlling the spacing between the RF cathode 236 and the substrate 102 on the substrate support assembly 208. In other embodiments, film properties may be modified and/or controlled by modifying the lower surface of the RF cathode 236. For example,“scooping” the lower surface of the RF cathode 236 (/.e., thinner cross-section at the center of the RF cathode 236 while thicker at the edges thereof) may be effective to improve stress uniformity. [0026] Temperature of the RF cathode 236 may be controlled (by, e.g., a process controller) during processing in the ALD processing chamber 200. Control of the temperature may be utilized to influence temperature of the process kit 202 and the substrate 102 and improve performance of the ALD processing. The temperature of the RF cathode 236 may be measured by a pyrometer (not shown), for example, or other sensor in the processing chamber 200. The RF cathode 236 may be heated by electric heating elements (not shown), for example, and cooled by circulation of cooling fluids, for example, a heat transfer fluid marketed under the tradename GALDEN ^® . Any power source capable of activating the gases into reactive species and maintaining the plasma of reactive species may be used. For example, RF or microwave (MW) based power discharge techniques may be used. The activation may also be generated by a thermally based technique, a gas breakdown technique, a high intensity light source (e.g., UV energy), or exposure to an x-ray source.

[0027] As discussed above, the pressures in the interior volume 228 of the processing chamber 200 and the volume 230 of the process kit 202 may be different, at least during ALD processing. In one example, the vacuum system 220 may maintain a first pressure within the interior volume 228 of the processing chamber 200 and a second pressure within the volume 230, the second pressure being greater than the first pressure. In some embodiments, the first pressure may be about 0.2 to about 0.3 Torr while the second pressure may be about 100 mTorr greater than the first pressure.

[0028] Figures 3A-3D are various views of the process kit 202, according to one embodiment described herein. Figure 3A is an isometric exploded view of the process kit 202. As shown in Figure 3A, the process kit 202 includes the mask frame 232 and the dielectric window 234. The process kit 202 may also include a sealing frame 235 which couples the dielectric window 234 to the mask frame 232. The sealing frame 235 may be coupled to the mask frame 232 by fasteners (not shown), such as bolts or screws. A seal 305 may be disposed between the sealing frame 235 and the mask frame 232. The mask frame 232 also includes compressible seals 252 on opposing sides thereof. In some embodiments, the process kit 202 includes a mask sheet 241 . The mask sheet 241 may be coupled to the mask frame 232 by fasteners (not shown), such as bolts or screws. In one embodiment, the mask sheet 241 includes a plurality of apertures 310 formed thereon.

[0029] The process kit 202 may also include the first manifold 242 and the second manifold 244. The first manifold 242 and the second manifold 244 are positioned on opposing sides of the mask frame 232. The sealing frame 235 may be made of metallic materials, such as aluminum. The mask frame 232 and the mask sheet 241 may be made of a metallic material with a low coefficient of thermal expansion (CTE), such as an alloy of iron and nickel (FeNi), which may be marketed under the tradename“INVAR” or“INVAR 36”. The dielectric window 234 may be made of quartz, a borosilicate glass material or a tempered glass material. The seal 305 and the compressible seal 252 may be made of a polymeric material, such as polytetrafluoroethylene (PTFE) or other type of elastic and/or compressible polymer material.

[0030] Figure 3B is a cross-sectional view of the process kit 202 along lines 3B-3B of Figure 3A. Figures 3C and 3D are partial enlarged views of ends of the process kit 202 shown in Figure 3B.

[0031] As shown in Figures 3C and 3D, the compressible seals 252 surround openings of the first and second manifolds 242, 244 at opposing sides of the mask frame 232. The first manifold 242, also the inlet port, is shown in Figure 3C, and the second manifold 244, also the outlet port, is shown in Figure 3D. The first plurality of channels 248 is shown in Figure 3C that fluidly couples the first manifold 242 to the volume 230. The second plurality of channels 250 is shown in Figure 3D that fluidly couples the volume 230 to the second manifold 244. In embodiments where the mask sheet 241 is utilized, an upper surface 345 of the mask sheet 241 bounds one side of the pluralities of channels 248, 250. A lower surface 350 of the mask sheet 241 is adapted to contact the substrate 102 (shown in Figure 2).

[0032] Figure 4A is a prospective view of the mask frame 232 of the process kit 202 of Figure 3A, according to one embodiment described herein. As shown in Figure 4A, the mask frame 232 includes a first side 402, a second side 404 opposite the first side 402, a third side 406 connecting the first side 402 and the second side 404, and a fourth side 408 opposite the third side 406 connecting the first side 402 and the second side 404. The first side 402 and the second side 404 may be substantially parallel to each other. The third side 406 and the fourth side 408 may be substantially parallel to each other. The first side 402 may be substantially perpendicular to the third side 406 or the fourth side 408, and the second side 404 may be substantially perpendicular to the third side 406 or the fourth side 408. In one embodiment, the mask frame 232 has a rectangular shape, as shown in Figure 4A. The first side 402 and the second side 404 may have a first length, and the third side 406 and the fourth side 408 may have a second length. The second length may be less than, equal to, or greater than the first length. In one embodiment, the second length is greater than the first length. In one embodiment, the first side 402 is adjacent the process gas inlet 210 (shown in Figure 2), and the second side 404 is adjacent the pumping port 212 (shown in Figure 2).

[0033] The first side 402 includes the first manifold 242 (shown in Figure 2) in fluid communication with the first plurality of channels 248. The second side 404 includes the second manifold 244 in fluid communication with the second plurality of channels 250. The third side 406 includes a third manifold 410 in fluid communication with a third plurality of channels 412. The fourth side 408 includes a fourth manifold 414 in fluid communication with the fourth plurality of channels 416. The third plurality of channels 412 and the fourth plurality of channels 416 are in fluid communication with the volume 230 (shown in Figure 2). Each of the third plurality of channels 412 may be substantially perpendicular to the third manifold 410, as shown in Figure 4A. In some embodiments, each of the third plurality of channels 412 forms an acute or obtuse angle with respect to the third manifold 410. Each of the fourth plurality of channels 416 may be substantially perpendicular to the fourth manifold 414, as shown in Figure 4A. In some embodiments, each of the fourth plurality of channels 416 forms an acute or obtuse angle with respect to the fourth manifold 414. The third manifold 410 and the fourth manifold 414 are in fluid communication with the second manifold 244. The third manifold 410 may have a same length or a different length as the fourth manifold 414. The third manifold 410 may extend about 20 to about 100 percent of the length of the third side 406. In one embodiment, the third manifold extends about 40 to about 80 percent of the length of the third side 406. The number of channels 412 connected to the third manifold 410 and the spacing between adjacent channels 412 may depend on the process and may be optimized. The fourth manifold 414 may extend about 20 to about 100 percent of the length of the fourth side 408. In one embodiment, the fourth manifold extends about 40 to about 80 percent of the length of the fourth side 408. The number of channels 416 connected to the fourth manifold 414 and the spacing between adjacent channels 416 may depend on the process and may be optimized. The third plurality of channels 412 and the fourth plurality of channels 416 may be aligned or offset.

[0034] In one embodiment, the manifolds 242, 244, 410, 414 and channels 248, 250, 412, 416 are enclosed by the mask sheet 241 (shown in Figure 2). In another embodiment, the mask sheet 241 and the mask frame 232 are portions of a monolithic piece of material. During operation, one or more precursor gases flow from the first side 402 to the second side 404. With the third and fourth plurality of channels 412, 416, i.e., side pumping channels, located in the sides 406, 408, precursor gases flow uniformity is improved, leading to improved layer thickness uniformity.

[0035] Figure 4B is a partial cross-sectional view of the mask frame 232 of Figure 4A, according to one embodiment described herein. As shown in Figure 4B, the second side 404 includes the second manifold 244 in fluid communication with the second plurality of channels 250. The second side 404 includes a surface 420 facing the substrate support assembly 208 (shown in Figure 2). A portion of each channel 250 forms an angle A with respect to the surface 420.

[0036] Figures 5A - 5B are schematic top views showing gas flow across a substrate. Figure 5A shows gas flow across a substrate without side pumping provided by the mask frame 232. As shown in Figure 5A, the gas does flow over the corners of the substrate 102, resulting in inferior film deposition uniformity and inefficient purge for ALD process. Figure 5B shows gas flow across the substrate 102 with side pumping by utilizing the mask frame 232. As shown in Figure 5B, the gas flow is over the corners of the substrate 102, leading to improved thickness uniformity of a layer deposited in the ALD processing chamber. [0037] In summary, a process kit is utilized in an ALD processing chamber. The process kit includes at least a mask frame having side pumping channels, which leads to improved gas flow uniformity. Improved gas flow uniformity leads to improved thickness uniformity of a layer deposited in the ALD processing chamber.

[0038] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.