Processing Kit Shield

Abstract

A process kit assembly for a process station, including a covering and a shield. The shield includes a lower shield portion configured to be sandwiched by the covering. The shield further includes an upper shield portion, the upper shield portion including a shield port extending from the inside to the outside of the upper shield portion. The upper shield portion further includes an innerly formed shade surface configured to shade the shield port from sputtering deposits. The upper shield portion further includes an outerly formed upper shield shoulder portion. The upper shield portion further includes a lower shield shoulder portion formed at the lower end of the upper shield portion. The upper shield portion is engageable with an adapter to form an annular chamber around the outside between the upper shield shoulder portion and the lower shield shoulder portion.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to substrate processing equipment, and more particularly, to a process kit shield for use in substrate processing equipment.

Background Art

[0002] Titanium nitride layers are conventionally deposited during a sputtering process that includes injecting nitrogen gas into a process chamber through a bottom-side nitrogen gas injection system. The nitrogen gas injected by the bottom-side injection system tends to be non-uniformly distributed along the surface of the substrate, and more nitrogen gas is seen at the upper edge of the substrate surface than at the upper surface of the substrate near the center. This non-uniform distribution is caused by the flow path of nitrogen gas into the process region of the process chamber that includes the substrate and the titanium-containing target. The bottom-side injection system injects nitrogen gas behind a shield disposed within the process chamber. Nitrogen flows into the processing region through the flow path between the pedestal and the shield. As nitrogen enters the process region through the flow path, the nitrogen gas flows around the upper edge of the substrate, and the amount of nitrogen gas above the substrate tends to decrease from the edge of the substrate toward the center. As a result, the deposited titanium nitride layer has a non-uniform nitrogen concentration, and the nitrogen concentration within the layer similarly decreases from the edge of the deposited layer toward the center. The non-uniform nitrogen concentration within the titanium nitride layer makes the threshold voltage of the deposited layer non-uniform. Thus, individual semiconductor devices fabricated on the substrate have different threshold voltages due to the non-uniformity of the nitrogen concentration.

[0003] Therefore, there is a need in the art for a process kit that promotes a uniform distribution of nitrogen gas along the surface of the target to deposit a titanium nitride layer having a more uniform nitrogen percentage across the deposited layer.

Summary of the Invention

[0004] In one or more embodiments, the process station includes a housing that includes walls and an adapter that includes at least one first gas inlet port. The process station further includes a pedestal located within the housing. The process station further includes a covering, a target, a shield, and a chamber. The covering includes a covering lip assembly having a top surface. The target includes a bottom surface located within the housing above the pedestal. The shield includes one or more shield ports and a shield lip assembly sandwiched between the covering lip assemblies. One or more shield ports are positioned below the bottom surface of the target and above the top surface of the covering to direct a first gas towards the target. The chamber is located between the adapter and the shield and communicates with one or more shield ports and at least one first gas inlet port.

[0005] In one or more embodiments, a process kit assembly for a process station includes a covering and a shield. The shield includes a lower shield portion configured to be sandwiched by the covering. The shield further includes an upper shield portion, the upper shield portion including a shield port extending from the inside to the outside of the upper shield portion. The upper shield portion further includes an innerly formed shade surface configured to shade the shield port from sputtering deposits. The upper shield portion further includes an outerly formed upper shield shoulder portion. The upper shield portion further includes a lower shield shoulder portion formed at the lower end of the upper shield portion. The upper shield portion is engageable with an adapter to form an annular chamber around the outside between the upper shield shoulder portion and the lower shield shoulder portion.

[0006] In one or more embodiments, a method for depositing a layer on a substrate includes injecting a first gas into a process area of ​​a process station through one or more shield ports formed in a shield located within the process station. The one or more shield ports are positioned to direct the first gas toward a target processing surface. The method further includes injecting a second gas into the process station behind the shield. The second gas flows into the processing area through a channel between the shield lip assemblies of the shield, which are sandwiched between coverings.

[0007] To allow for a more detailed understanding of the features enumerated above in this disclosure, a more detailed description of this disclosure, which has been briefly summarized above, can be given with reference to embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings show only exemplary embodiments of this disclosure and should therefore not be considered to limit the scope of this disclosure, as this disclosure may allow for other equally effective embodiments. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view of a process station according to one embodiment. [Figure 2] This is an enlarged cross-sectional view of the process station within the enclosed area shown in Figure 1. [Figure 3] This graph shows a comparison of nitrogen heterogeneity within the titanium nitride layer. [Figure 4] This is a flowchart of a sputtering process for depositing a titanium nitride layer on a substrate according to one embodiment. [Modes for carrying out the invention]

[0009] For ease of understanding, the same reference numerals were used where possible to designate identical elements common to the figures. Elements and features of one embodiment are intended to be usefully incorporated into other embodiments without further detail.

[0010] Apparatus for reducing non-uniformity of nitrogen percentage (e.g., concentration) within a titanium nitride layer is provided herein. The apparatus includes a shield that directs nitrogen gas toward a target so that the nitrogen gas is distributed more uniformly across the target during the sputtering process.

[0011] Figure 1 shows a cross-sectional view of the process station 100. The process station 100 may be a station in a substrate processing system, such as a cluster tool, which includes multiple processing stations configured to process substrates. As shown in Figure 1, the process station 100 includes a housing 110, a pedestal 120, an exhaust assembly 130, a process kit assembly 140, a source assembly 170, a first gas assembly 180, and a second gas assembly 190. A controller 101 communicates with the process station 100 and controls one or more components of the process station 100.

[0012] The housing 110 includes one or more chamber walls 112 and an adapter 116. One or more chamber walls 112 are grounded, and the adapter is grounded to the chamber walls 112. The adapter 116 is attached to the upper end of one or more chamber walls 112 and supports the source assembly 170. The adapter 116 may include inlet ports 117, for example, two inlet ports 117 located on opposing sides of the adapter 116. The inlet ports 117 communicate with an annular chamber 165 located between the adapter 116 and the shield 160 of the process kit assembly 140. In some embodiments, one or more chamber walls 112 and the adapter 116 are made of an aluminum alloy. The adapter 116 is described in more detail with respect to Figure 2.

[0013] The pedestal 120 is at least partially positioned inside the process station 100 to support the substrate 104 during processing. The pedestal 120 may be an electrostatic chuck. The pedestal 120 includes a support surface 121 and a shaft 122. The support surface 121 supports the substrate 104 during processing. A bellows 123 is positioned around the shaft 122 and engages with the lower surface 111 of the housing 110 to seal the inside of the process station 100 from the external environment (e.g., air). A pedestal power supply 127 is coupled to the pedestal 120 to supply RF power and / or DC power to the pedestal 120 during processing. For example, the pedestal power supply 127 may be configured to bias one or more chuck electrodes (not shown) positioned on the pedestal 120. A backside gas source 128 can be coupled to the pedestal 120 to inject backside gas (e.g., N2, He, Ar) through the pedestal 120 into one or more channels (not shown) formed in the support surface 121. These one or more channels allow the backside gas to flow directly beneath the backside of the substrate 104, thereby regulating the temperature of the substrate 104 during processing. In some embodiments, an additional temperature control system 129 is coupled to the pedestal 120. For example, the temperature control system 129 may be configured to power one or more heaters located in the pedestal 120 to regulate the temperature of the substrate 104. In some embodiments, the temperature control system 129 may be a coolant system that circulates a liquid coolant through a channel formed in the pedestal 120 to regulate the temperature of the substrate 104.

[0014] Figure 1 shows the pedestal 120 in the process position. The pedestal 120 is vertically movable within the housing 110 between a transfer position (e.g., a lower position) and a process position (e.g., an upper position), including positions in between. In some embodiments, a robot (not shown) can insert the substrate 104 into the housing 110 through a slit valve (not shown) while the pedestal 120 is in the transfer position, and when the pedestal 120 is lowered to the transfer position, the covering 150 is lifted away from the pedestal 120 by being supported by one or more lift pins (not shown) or by another part of the process kit assembly 140. The substrate 104 is then transferred from the robot to the support surface 121, for example by using additional lift pins (not shown) to facilitate the transfer of the substrate 104 from the robot to the pedestal 120. The covering 150 is lowered and returns to engage with the pedestal 120, or subsequently engages with the pedestal 120 when the pedestal 120 is raised to the process position to facilitate processing of the substrate 104.

[0015] The exhaust assembly 130 is coupled to the housing 110. The exhaust assembly 130 may include a conduit 132 that connects an exhaust port 131 formed in the housing 110 to a pump 136 configured to exhaust gas from inside the processing station 100. A valve 138 may be coupled to the conduit 132. The exhaust assembly 130 is used to exhaust the inside of the process station 100 and maintain a desired pressure inside the process station 100, for example, to maintain a desired pressure in the process area 106.

[0016] The process kit assembly 140 includes various components that can be easily removed from inside the process station 100, for example, to clean sputtering deposits from component surfaces, to replace or repair eroded components, or to adapt the process station 100 for other processes. In one embodiment, the process kit assembly 140 includes a deposit ring 145, a covering ring 150, and a shield 160. The deposit ring 145 engages with the pedestal 120, and the covering ring 150 engages with the deposit ring 145. For example, the covering ring 150 can rest on the deposit ring 145. The deposit ring 145 and the covering ring 150 move relative to the shield 160 as the pedestal 120 moves within the process station 100. The covering ring 150 is positioned to sandwich the shield 160 such that a flow channel that can be selectively closed exists between the covering ring 150 and the shield 160.

[0017] The shield 160 is located within the housing 110 and coupled to the adapter 116. The shield 160 is grounded by contact with the adapter 116, which is grounded to the chamber wall 112. The shield 160 typically surrounds the processing surface 172A of the physical vapor deposition (PVD) target 172 of the source assembly 170. The shield 160 covers and shades the components behind it, reducing the accumulation of sputtering deposits from the target 172 on the components and surfaces behind the shield 160. For example, the shield 160 can protect the chamber wall 112, the adapter 116, and the surface of the pedestal 120.

[0018] In some embodiments, the shield 160 is a single-piece shield. A single-piece shield improves the thermal stability of the shield 160 compared to a multi-piece shield. The shield 160 can be formed from a suitable material that is compatible with PVD processes such as the deposition processes of titanium (Ti), titanium nitride (TiN), tungsten (W), tungsten nitride (WN), copper (Cu), or aluminum (Al). For example, the shield 160 may include stainless steel, aluminum, titanium, aluminum silicon, copper, or a combination thereof.

[0019] The shield 160 includes one or more shield ports 161 that communicate with an annular chamber 165 positioned between the shield 160 and the adapter 116. As will be discussed in more detail with respect to Figure 2, one or more shield ports 161 are positioned to facilitate the deposition of a titanium nitride layer onto the substrate 104 having a more uniform nitrogen percentage (e.g., concentration) throughout the layer.

[0020] Figure 1 shows a source assembly 170 adapted to perform a PVD process (e.g., a sputtering process). An exemplary source assembly 170 includes a magnetron assembly 171, a target 172, a source assembly wall 173 coupled to a housing 110, a lid 174, a sputtering power supply 175, and a backing plate 177. The target 172 contains the material to be deposited on the substrate 104 during sputtering, such as a metal or metal oxide. For example, the target 172 can be fabricated from a titanium-containing material to facilitate the deposition of a titanium nitride layer on the substrate 104. Although the target 172 is shown as a concave target in Figure 1, the target 172 can be a flat target or a target with a different configuration. The backing plate 177 is coupled to the target 172 and positioned between the target 172 and the magnetron assembly 171. The backing plate 177 can support the target 172 during sputtering and improve the structural stability of the target 172, etc. A dielectric insulator 118 is placed between the adapter 116 and the backing plate 177. The magnetron assembly 171 includes a magnetron region 179, which is rotated by the magnetron 171A using a magnetron rotary motor 176 during processing. The target 172 and the magnetron assembly 171 are generally cooled by supplying a cooling fluid (e.g., deionized water) to the magnetron region 179 from a fluid recirculation device (not shown). The magnetron assembly 171 includes a plurality of magnets 171B configured to generate a magnetic field extending beneath the processing surface 172A of the target 172 to facilitate the sputtering process performed in the process region 106 during the PVD process. The process region 106 is an internal space within the process station 100 where the sputtering process is performed. The process region 106 includes the target 172 and the support surface 121, and is at least partially defined by them. The process region 106 is also bounded by a shield 160 sandwiched between coverings 150.

[0021] The first gas assembly 180 is configured to inject the first gas into the process area 106 through an inlet port 117 formed in the adapter 116, an annular chamber 165, and one or more shield ports 161 formed in the shield 160. The first gas assembly 180 includes a first gas source 182, which can be a gas panel. The first gas can be one or more process gases, such as one or more precursor gases. For example, the first gas source 182 may supply a nitrogen-containing gas, such as nitrogen gas (N2), to interact with a titanium-containing target 172, thereby forming a titanium nitride layer on the substrate 104. In some embodiments, as shown in Figure 1, a branched fluid conduit 184 connects the first gas source 182 to two inlet ports 117 formed on opposing sides of the adapter 116. A first mass flow controller 186 can be coupled to the first conduit 184 to regulate the amount of the first gas flowing into the process area 106. The first gas assembly 180 is an upper gas injection assembly, as the first gas is injected into the process station 100 on the upper side of the shield 160 (for example, the surface of the shield 160 facing the process area 106).

[0022] The second gas assembly 190 is configured to inject the second gas into the interior of the process station 100. The second gas assembly 190 includes a second gas source 192. The second gas source 192 can be a gas panel configured to supply the second gas into the lower region 103 of the process station 100 through a second conduit 194 extending from the second gas source 192 to a second inlet port 191 formed in the chamber wall 112 of the housing 110. The second inlet port 191 is positioned below the shield 160 to inject the second gas into the lower region 103 of the process station 100, which is located between the bottom side of the shield 160 (e.g., the surface of the shield facing the lower region 103) and the chamber wall 112. As a result, the second gas flows from the lower region 103 into the process region 106 through a flow path between the shield 160 and the covering 150. Therefore, the second gas assembly 190 is a bottom-side gas injection system, as the second gas must be injected behind the shield 160 and flow through a channel between the covering 150 and the shield 160 to enter the process area 106. The second gas can be an inert gas such as argon. In some embodiments, the second gas is a mixture of one or more gases. The second gas can flow into the process area 106 during processing of the substrate 104, for example, while the first gas is being injected into the process area 106. In some embodiments, the second gas is used to purge the process area 106 of the first gas. A second mass flow controller 196 can be coupled to the second conduit 194 to adjust the amount of the second gas flowing into the lower area 103. In some embodiments, the first gas source 182 and the second gas source 192 can be the same gas source, such as being the same gas panel. In some embodiments, the second inlet port 191 is located below the support surface 121, such as on the lower surface 111.

[0023] The controller 101 can include a programmable central processing unit (CPU) operable using a memory (e.g., non-volatile memory) and support circuitry. The support circuitry has conventionally included caches, clock circuits, input / output subsystems, power supplies, etc., and combinations thereof, coupled to the CPU and to various components of the station 100 to facilitate control of the station 100. For example, in some embodiments, the CPU is one of any form of general-purpose computer processor used in an industrial environment, such as a programmable logic controller (PLC) for controlling various polishing system components and sub-processors. The memory coupled to the CPU is non-transitory and is generally one or more of readily available memories such as random access memory (RAM), read only memory (ROM), floppy disk drives, hard disks, or other forms of local or remote digital storage.

[0024] As used herein, the memory is in the form of a computer-readable storage medium (e.g., non-volatile memory) that includes instructions that, when executed by the CPU, facilitate the operation of the station 100. The instructions in the memory are in the form of a program product (e.g., middleware application, device software application, etc.), such as a program for implementing the methods of the present disclosure. The program code can conform to any one of several different programming languages. In one example, the present disclosure can be realized as a program product stored on a computer-readable storage medium for use in a computer system. The program of the program product defines the functions of the embodiments (including the methods and operations described herein).

[0025] Exemplary computer-readable storage media include, without limitation, (i) non-writable storage media where information is permanently stored (e.g., CD-ROM disks readable by a CD-ROM drive, flash memory, ROM chips, or read-only memory devices within a computer such as any type of solid-state non-volatile semiconductor memory), and (ii) writable storage media where modifiable information is stored (e.g., floppy disks within a diskette drive or hard disk drive, or any type of solid-state random access semiconductor memory). Such computer-readable storage media are embodiments of the present disclosure when they hold computer-readable instructions that direct the functions of the methods described herein.

[0026] FIG. 2 is an enlarged view of the enclosed area in FIG. 1 to better show the adapter 116, the process kit assembly 140, and the annular chamber 165. As shown in FIG. 2, the adapter 116 includes a lower adapter portion 211 and an upper adapter portion 212. The lower adapter portion 211 is engaged with the upper end of the chamber wall 112. A seal 216 is disposed between the interface of the lower adapter portion 211 and the chamber wall 112 to prevent communication between the lower region 103 and the external environment. Another seal 216 is disposed between the interface of the upper adapter portion 212 and the lower adapter portion 211.

[0027] The upper adapter portion 212 includes an upper adapter shoulder 213, and the lower adapter 211 includes a lower adapter shoulder 214. The inner surface 218 of the adapter 116 extends from the upper adapter shoulder 213 to the lower adapter shoulder 214. The inlet port 117 is formed in the lower adapter portion 211 and terminates at an opening formed in the inner surface 218. The lower adapter portion 211 can be attached to the upper adapter portion 212 by a fastener (not shown) such as a bolt. The fastener can be inserted into an opening formed in the upper adapter shoulder 213.

[0028] The shield 160 is shown as a single-piece metal body including an upper shield portion 220 and a lower shield portion 230. In some embodiments, the shield 160 may be made of multiple parts. The upper shield portion 220 can be a generally cylindrical body having an inner 225 and an outer 226. The upper shield portion 220 includes an upper shield shoulder portion 221 formed on the outer 226, protruding from the cylindrical body. The upper shield portion 220 further includes a lower shield shoulder portion 222 at the bottom end (e.g., the lower end) of the upper shield portion 220. As shown, the lower shield shoulder portion 222 is positioned adjacent to the location where the upper shield portion 220 and the lower shield portion 230 connect. The upper shield shoulder portion 221 and the lower shield shoulder portion 222 are separated by an outer surface 223 facing the inner surface 218 of the adapter 116. The upper shield shoulder 221 engages with the upper adapter shoulder 213, and the lower shield shoulder 222 engages with the lower adapter shoulder 214. The annular chamber 165 (e.g., an annular plenum) is positioned between the upper shield portion 220 and the adapter 116, between opposing surfaces 218 and 223. The annular chamber 165 is also positioned between adjacent upper shoulders 213, 221 and lower shoulders 214, 222. The annular chamber 165 can extend completely around the upper shield portion 220. Seals 217, such as O-rings, are positioned between the interfaces of adjacent upper shoulders 213, 221 and between the interfaces of adjacent lower shoulders 214, 222 to prevent leakage of the first gas between them. Thus, the seals 217 maintain the pressure integrity of the annular chamber 165 so that the nitrogen pressure is uniform within the annular chamber 165. Maintaining a uniform pressure within the annular chamber 165 allows the gas to exit one or more shield ports 161 at a constant flow rate, promoting a uniform distribution of nitrogen gas across the treatment surface 172A of the target 172.

[0029] Fasteners 215, such as bolts, are used to secure the shield 160 to the adapter 116 and to ensure that the seal 217 is maintained in a tightly sealed engagement with the adapter 116 and the shield 160. The fasteners 215 may extend through the upper shield shoulder 221 into the lower adapter portion 211 and the upper adapter portion 212.

[0030] The upper end 227 of the upper shield portion 220 is positioned between the protruding edge region 270 of the concave target 172 and the dielectric insulator 118. A dark space gap 201 exists between the electrically biased target 172 and the upper end 227. The dark space gap 201 extends further between the upper end 227 and the dielectric insulator 118. The dark space gap 201 is sized to limit and / or prevent the persistent presence of plasma, and to prevent short circuits (grounding) or arching of the biased target 172 to the grounded shield 160. Thus, the upper end 227 is sized and shaped to form the dark space gap 201 when the shield 160 is placed in the process station 100 for processing operations.

[0031] One or more shield ports 161 are formed through the upper shield portion 220 and extend from the inside 225 to the outside 226. The one or more shield ports 161 are arranged around the process region 106, such as being arranged at equal intervals around the shield 160. Although not bound by theory, directing the nitrogen gas towards the target 172 is thought to result in a more complete reaction, improving the uniformity of nitrogen concentration within the deposited titanium nitride layer, as opposed to directing the nitrogen gas towards the substrate. By improving the uniformity of nitrogen concentration within the deposited titanium nitride layer, the uniformity of the threshold voltage across the layer is also improved.

[0032] As shown in Figure 2, the center of the shield port 161 is positioned at a distance D1 below the target processing surface 172A. This distance D1 is shown as the vertical distance between the center of the shield port 161 and the nearest part of the target 172, such as the bottom of the protruding edge region 270. The shield port 161 is spaced at a distance D1 from the processing surface 172A to promote a uniform distribution of a first gas (e.g., nitrogen gas) across the entire processing surface 172A during the sputtering (e.g., PVD) process. In other words, the shield port 161 is positioned at a certain distance from the target 172 to direct the injected nitrogen gas toward the target 172 and to promote a uniform distribution of the nitrogen gas across the processing surface 172A. Directing the gas toward the target 172 promotes the reaction between the target 172 and the nitrogen gas, while reducing the reaction between the nitrogen gas and the material deposited on the surface of the substrate 104. As a result, the percentage of nitrogen within the deposited titanium nitride layer is more uniform from the center to the edge of the titanium nitride layer than in titanium nitride layers deposited using a bottom-side nitrogen injection process.

[0033] If one or more shield ports 161 are positioned too close or too far from the target 172, the uniformity of nitrogen concentration within the titanium nitride layer will be reduced. If one or more shield ports 161 are positioned too close to the target 172, the nitrogen gas will not be distributed very uniformly across the processing surface 172A, with more nitrogen gas concentrated at the edges of the processing surface 172A compared to the center of the processing surface 172A. This non-uniform distribution of nitrogen will result in a titanium nitride layer with a less uniform nitrogen concentration. If one or more shield ports 161 are positioned too far from the target 172, such as coinciding with or perpendicularly below the top surface (see top surface 259) of the covering 150, the covering 150 may deflect the nitrogen gas flow into the process area 106, resulting in a non-uniform nitrogen concentration within the titanium nitride layer. Furthermore, if the shield ports 161 are positioned too far from the target 172, the nitrogen gas may react primarily with the growing titanium nitride layer on the substrate rather than with the target 172.

[0034] Therefore, the shield port 161 is positioned at a distance D1 from target 172A, which is an optimal location for promoting nitrogen distribution and further avoiding or minimizing flow interference associated with the covering 150. In some embodiments, D1 is between 1 inch and 4 inches, for example, about 4 inches, for example, about 3.5 inches, for example, about 3 inches, for example, about 2.5 inches, for example, about 2 inches, for example, about 1.5 inches, for example, about 1.0 inch. In some embodiments, D1 is about 2.5 inches (about 63.5 mm), for example, within about 1% of 2.5 inches, for example, within about 0.2% of 2.5 inches. In some embodiments, D1 is based on the diameter of target 172. For example, the ratio of the substrate diameter to the position of the shield port 161 may be a ratio of about 6.8.

[0035] In some embodiments, one or more shield ports 161 are eight or more shield ports. Each shield port 161 may have a diameter of approximately 0.8 inches (approximately 20.32 mm). In some embodiments, one or more shield ports 161 may be more or fewer than eight shield ports.

[0036] The upper shield portion 220 further includes a shadow surface 224 formed on the inner side 225 adjacent to one or more shield ports 161. The shadow surface 224 shades one or more shield ports 161 from sputtering of material from the target 172, thereby limiting and / or preventing the accumulation of sputtered material in one or more shield ports 161. In other words, the shadow surface 224 helps prevent the accumulation of material in the shield ports 161 that could obstruct the flow of a first gas through the shield ports 161 during processing. The shadow surface 224 may be a contoured surface of a projection formed on the inner side 225 that extends from the cylindrical body at a location above the shield ports 161 and terminates at the entrance to the shield ports 161. The shadow surface 224 may be a continuous feature extending around the inner side 225 of the upper shield portion 220 around the process area 106. For example, the shadow surface 224 may be a contoured circumferential projection extending around the inner side 225 of the upper shield portion 220. In some embodiments, the upper shield portion 220 includes a plurality of discontinuous shaded surfaces 224 corresponding to each shield port 161.

[0037] The lower shield portion 230 includes a shield lip assembly 231 that interfaces with the covering 150. For example, the shield lip assembly 231 may include a lower surface 232 extending inward from the outer edge 233 of the lower shield portion 230. The shield lip assembly 231 includes a lip 234 positioned around the inner edge 235 of the lower surface 232, and extending upward from the inner edge 235 toward the upper shield portion 220.

[0038] The deposition ring 145 and the covering ring 150 work together to reduce the formation of sputter deposits on the periphery of the substrate support surface 121 and on the protruding edge 204 of the substrate 104. The covering ring 150 sandwiches the shield lip assembly 231 so that a channel that can be selectively closed exists between the covering ring 150 and the shield 160.

[0039] The deposition ring 145 engages with the pedestal 120 and is typically formed in an annular shape or annular band surrounding the support surface 121. The deposition ring 145 can be formed from a dielectric material resistant to the sputtering process, such as being made from a ceramic material such as aluminum oxide.

[0040] The covering 150 shown in Figure 2 is a tall covering. The covering 150 includes an annular body 251 having a footing 252. The covering 150 is supported on the deposition ring 145 by the engagement of the footing 252 with the deposition ring 145. The covering 150 surrounds and at least partially covers the deposition ring 145, shading the deposition ring 145 from most of the sputtering deposits. The covering 150 is made of a material that can withstand erosion by sputtering plasma, such as a metallic material such as stainless steel, titanium, or aluminum, or a ceramic material such as aluminum oxide. The annular body 251 further includes a protruding brim 253 positioned to reduce the deposition of sputtering deposits on the upper surface of the deposition ring 145.

[0041] The covering 150 further includes a covering lip assembly 255 extending upward from the annular body 251. The covering lip assembly 255 includes an inner ring 256 and an outer ring 257, separated from each other by an upper portion 258. The inner ring 256 and the outer ring 257 extend downward from the upper portion 258 and are positioned radially outward from the footing 252 of the brim 253. A gap is provided between the rings 256 and 257, which are sized to sandwich the shield lip assembly 231. As shown, the lip 234 of the shield 160 extends upward between the adjacent downward-extending inner cylindrical ring 256 and outer cylindrical ring 257 of the covering 150. The covering lip assembly 255 has a height that shades the substrate 104 from nitrogen gas injected into the process area 106 from the shield port 161. In other words, the covering lip assembly 255 has a height that obstructs the line of sight between the shield port 161 and the surface of the substrate 104, thereby limiting the amount of nitrogen that reaches the surface of the substrate 104. As shown in Figure 2, the covering lip assembly 255 extends above the substrate support surface 121. Furthermore, the upper portion 258 is positioned between the upper shoulder portion 221 and the lower shoulder portion 222 of the shield 160, and is also shown to be positioned below the shield port 161 such that the top surface 259 of the upper portion 258 is below the shield port 161. The height of the covering lip assembly 255 can be selected based on the desired shading effect.

[0042] In addition, the covering lip assembly 255 has a height that accommodates the vertical movement of the pedestal 120. As shown in Figure 2, the pedestal 120 is positioned such that the shield lip assembly 231 does not come into contact with the covering lip assembly 255. Thus, a flow path exists between the sandwiched shield lip assembly 231 and the covering lip assembly 255, thereby allowing a second gas to flow from the lower region 103 into the process region 106. The flow path can exist when the pedestal 120 is in the process position. As shown in Figure 2, the flow path is a complex, intricate S-shaped path defined by the sandwiched shield lip assembly 231 and the covering lip assembly 255. The pedestal 120 can be moved to one or more positions to change the length of the flow path, for example, by raising or lowering the covering lip assembly 255 relative to the shield lip assembly 231. In some embodiments, the outer ring 257 and lip 234 are sized to lower the pedestal 120 so that the lip 234 contacts the upper portion 258, thereby sealing the process area 106 away from the lower area 103.

[0043] Figure 2 further shows the distance D2 between the top surface of the substrate 104 being processed and the flat portion of the processing surface 172A of the target 172. In some embodiments, the distance D2 is between approximately 150 mm and 190 mm, for example, between approximately 160 mm and 180 mm. The pedestal 120 can be moved vertically during processing to selectively change the distance D2 between the processing surface 172A of the target 172 and the surface of the substrate 104 during processing.

[0044] Figure 3 shows Graph 300 comparing the percentage non-uniformity of nitrogen in different titanium nitride layers of 35 angstroms thickness. The Y-axis shows the percentage (expressed as NU(%)) of nitrogen non-uniformity in the titanium nitride layer measured across the substrate 104. The first set of bar graphs on the left side of Graph 300 (e.g., bars 301 and 302) compares the nitrogen non-uniformity in titanium nitride layers formed by sputtering processes using both RF and DC power. Bar 301 represents the nitrogen non-uniformity in titanium nitride layers formed by conventional bottom-side gas injection (BGI). Bar 302 represents the nitrogen non-uniformity in titanium nitride layers formed using the top-side gas injection (TGI) process disclosed herein. As shown, the titanium nitride layer formed using the conventional bottom-side gas injection technique has a greater percentage of nitrogen non-uniformity than the titanium nitride layer formed using top-side gas injection.

[0045] The second set of bar graphs on the right side of Graph 300 (e.g., bars 303 and 304) compares the nitrogen heterogeneity in titanium nitride layers formed by a sputtering process using DC power only. Bar 303 represents the nitrogen heterogeneity in a titanium nitride layer formed by conventional bottom-side gas injection. Bar 304 represents the nitrogen heterogeneity in a titanium nitride layer formed using the top-side gas injection process disclosed herein. As shown in the figure, the titanium nitride layer formed using the conventional bottom-side gas injection technique has a greater percentage of nitrogen heterogeneity than the titanium nitride layer formed using top-side gas injection.

[0046] In some embodiments, the titanium nitride layer formed using the processes disclosed herein has nitrogen heterogeneity between about 0.5% and about 0%. For example, the nitrogen heterogeneity may be less than about 0.45%, for example less than 0.4%, for example less than about 0.35%, for example less than 0.3%, for example less than 0.25%, for example less than 0.2%, for example less than about 0.5%, etc.

[0047] Figure 4 is a flowchart of a sputtering process 400 for depositing a titanium nitride layer on a substrate in a process station 100. As shown by activity 401, power is applied to the titanium sputtering target 172 by a sputtering power supply 175 while the substrate 104 is chucked to the support surface 121 of the pedestal 120. As shown by activity 402, nitrogen is injected into the process area 106 from a first gas assembly 180. The nitrogen enters the process area 106 on the upper side of the shield 160 through a shield port 161 positioned to direct the nitrogen gas toward the processing surface 172A of the titanium-containing target 172. As shown by activity 403, a second gas, such as argon, is injected into the lower area 103 of the process station 100 from a second gas assembly 190. The second gas flows into the process area 106 through a channel between the sandwiched shield lip assembly 231 and the covering lip assembly 155. The length of the channel may be selectively changed during processing. In some embodiments, the pedestal 120 may be moved to selectively open and close the flow path during processing. The thickness of the deposited titanium nitride layer can be adjusted by changing the processing time of the sputtering process 400.

[0048] In some embodiments, the processes disclosed herein can be used to achieve a desired concentration of material in a layer formed on a substrate by sputtering. For example, the processes disclosed herein can be used to deposit tantalum nitride (TaN), tungsten nitride (WN), silicon nitride (SiN), or aluminum nitride (AlN) layers with improved nitrogen concentration uniformity.

[0049] While the foregoing applies to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the fundamental scope of the present disclosure, the scope of which will be determined by the appended claims.

Claims

1. It is a process station, A housing including a wall and an adapter including at least one first gas inlet port, A pedestal located within the housing, A covering including a covering lip assembly having a top surface, A target including a lower surface disposed within the housing above the pedestal, A shield comprising one or more shield ports and a shield lip assembly sandwiched between the covering lip assemblies, wherein the one or more shield ports are positioned below the lower surface of the target and above the top surface of the covering in order to direct a first gas toward the target, A chamber disposed between the adapter and the shield, wherein the chamber communicates with the one or more shield ports and the at least one first gas inlet port. A process station including a process station.

2. The process station according to claim 1, wherein the shield includes at least one shaded surface configured to shield the one or more shield ports from sputtering of material from the target.

3. The process station according to claim 2, wherein the at least one shaded surface is a shaded surface extending around the inside of the shield.

4. The process station according to claim 2, wherein the at least one shaded surface is a plurality of discontinuous shaded surfaces corresponding to each of the shielded ports of the at least one shielded port.

5. The process station according to claim 1, wherein the adapter includes an upper adapter portion and a lower adapter portion, and the at least one first gas inlet port is formed by penetrating the lower adapter portion.

6. The shield includes an upper shield shoulder portion and a lower shield shoulder portion, The adapter includes an upper adapter shoulder engaged with the upper shield shoulder and a lower adapter shoulder engaged with the lower shield shoulder, and the chamber is positioned between the lower shield shoulder and the upper shield shoulder. The process station according to claim 1.

7. The process station according to claim 1, wherein one or more shield ports are arranged between the upper shield shoulder and the lower shield shoulder.

8. The process station according to claim 1, further comprising a second gas inlet port formed in the housing at a location behind the shield, wherein a second gas assembly is configured to inject a second gas through the second gas inlet port into the area behind the shield.

9. The process station according to claim 8, wherein the second gas is argon.

10. The process station according to claim 1, wherein the target is a concave target, and the lower surface is the surface of the protruding edge region of the concave target.

11. A process kit assembly for a process station, Covering, It is a shield, The lower shield portion is configured to be sandwiched between the aforementioned coverings, and The upper shield portion, A shield port extending from the inside to the outside of the upper shield portion, The inner surface formed to cast a shadow over the shield port with respect to the sputtering deposit, The upper shield shoulder portion formed on the outer side, Lower shield shoulder portion formed at the lower end of the upper shield portion The upper shield section, Includes, The upper shield portion is engageable with an adapter to form an annular chamber around the outer side between the upper shield shoulder and the lower shield shoulder. Shield and, Process kit assembly, including

12. The process kit assembly according to claim 11, wherein the upper shield portion includes an upper end, and the upper end is configured to form a dark space gap between the upper end and the target.

13. The process kit assembly according to claim 11, wherein the shield port is positioned between the bottom surface of the target and the top surface of the covering when the shield and the covering are placed in the processing station.

14. The process kit assembly according to claim 11, wherein the negative surface extends above the port and around the inner surface.

15. The process kit assembly according to claim 11, wherein the covering includes a covering lip assembly configured to sandwich the shield lip assembly of the lower shield portion, and a flow path is disposed between the covering lip assembly and the shield lip assembly.

16. The process kit assembly according to claim 11, wherein the shield port is located between the upper shield shoulder and the lower shield shoulder.

17. A method for depositing layers on a substrate, Injecting a first gas into the process area of ​​a process station through one or more shield ports formed in a shield located within the processing station, wherein the one or more shield ports are positioned to direct the first gas toward the target processing surface. Injecting a second gas into the processing station behind the shield, wherein the second gas flows into the processing area through a channel between the shield lip assembly of the shield, which is sandwiched by the covering. Methods that include...

18. The method according to claim 17, wherein the non-uniformity of the first gas in the layer is less than 0.5%.

19. The method according to claim 17, wherein the layer is a titanium nitride layer, the first gas is nitrogen gas, and the target is a titanium-containing target.

20. The method according to claim 19, wherein the non-uniformity of nitrogen heterogeneity in the titanium nitride layer is less than 0.5%.

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