CN112262228A

CN112262228A - Temperature controlled gas diffuser for flat panel processing apparatus

Info

Publication number: CN112262228A
Application number: CN201980039055.4A
Authority: CN
Inventors: 苏希尔·安瓦尔; 吉万·普拉卡什·塞奎拉
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2018-06-08
Filing date: 2019-06-07
Publication date: 2021-01-22
Also published as: JP2021525963A; KR20210006019A; KR102572740B1; WO2019236937A1; JP7164632B2

Abstract

Embodiments described herein provide a gas distribution assembly that improves uniformity of a deposited film or a film to be etched. One embodiment of the gas distribution assembly includes a diffuser having a top diffuser plate and a plurality of first gas channel segments disposed in the top diffuser plate. Each first gas channel is adjacent to at least one fluid channel disposed in the top diffuser plate. Each fluid channel is connected to a supply channel disposed in the top diffuser plate, the supply channel having a supply inlet configured to be coupleable to a fluid supply conduit of a heat exchanger. Each fluid passage is connected to a return passage provided in the top diffuser plate. A return channel having a return outlet is configured to be coupleable with a fluid return conduit of the heat exchanger. A bottom diffuser plate is coupled with the top diffuser plate.

Description

Temperature controlled gas diffuser for flat panel processing apparatus

Technical Field

Embodiments of the present disclosure generally relate to processing chambers, such as plasma enhanced vapor deposition (PECVD) chambers. More particularly, embodiments of the present disclosure relate to gas distribution assemblies for processing chambers.

Background

Chemical Vapor Deposition (CVD) and Plasma Enhanced Chemical Vapor Deposition (PECVD) are commonly used to deposit thin films on substrates such as transparent substrates for flat panel displays or semiconductor wafers. CVD and PECVD are typically accomplished by introducing a precursor gas or gas mixture into a vacuum chamber containing the substrate. The precursor gas or gas mixture is typically directed downwardly through a gas diffuser located near the top of the chamber. A diffuser plate is placed a small distance above a substrate disposed on a heated substrate support so that the diffuser and precursor gas or gas mixture are heated by radiant heat from the substrate support. During PECVD, a precursor gas or gas mixture in the chamber is energized (e.g., excited) into a plasma by applying Radio Frequency (RF) power to the chamber by one or more RF sources coupled to the chamber. The excited gas or gas mixture reacts to form a layer of material on the surface of the substrate disposed on the heated substrate support. Volatile by-products generated during the reaction are pumped out of the chamber by an exhaust system.

The plates processed by CVD and PECVD processes are typically large, often exceeding 370mmx470 mm. Thus, a larger gas diffuser plate (or gas distribution plate) is utilized to provide uniform process gas flow over a relatively larger sized flat plate, especially as compared to gas diffuser plates used for 200mm and 300mm semiconductor wafer processing. Since the gas diffusion plate is large and is heated only by radiant heat from the substrate support and the excited plasma, the temperature distribution of the gas diffusion plate is not uniform and results in film deposition with non-uniform thickness or non-uniform film etching.

Accordingly, there is a need for improved gas distribution assemblies that improve the uniformity of the deposited film or film to be etched.

Disclosure of Invention

In one embodiment, a diffuser is provided. The diffuser includes a top diffuser plate having an upstream surface and a downstream surface and a plurality of first gas passage sections (gas passage sections) disposed in the top diffuser plate. Each first gas channel is adjacent to at least one fluid channel disposed in the top diffuser plate. Each fluid channel is connected to a supply channel disposed in the top diffuser plate, the supply channel having a supply inlet configured to be coupleable to a fluid supply conduit of the heat exchanger. Each fluid passage is connected to a return passage provided in the top diffuser plate. A return channel having a return outlet is configured to be coupleable with a fluid return conduit of the heat exchanger. The bottom diffuser plate is coupled to the top diffuser plate. The bottom diffuser plate has an upstream surface and a downstream surface.

In another embodiment, a diffuser is provided. The diffuser includes a top diffuser plate having an upstream surface and a downstream surface and a plurality of first gas channel segments disposed in the top diffuser plate. Each first gas channel is adjacent to at least one fluid channel disposed in the top diffuser plate. Each of the fluid passages is connected to one of a supply passage and a supply bypass passage provided in the top diffuser plate. The supply channel has a supply inlet configured to be coupleable with a fluid supply conduit of the heat exchanger. The supply bypass passage is in fluid communication with the supply passage. Each fluid passage is connected to one of a return passage and a return bypass passage provided in the top diffuser plate. The return channel has a return outlet configured to be coupleable with a fluid return conduit of the heat exchanger. The return bypass passage is in fluid communication with the return passage. The bottom diffuser plate is coupled to the top diffuser plate. The bottom diffuser plate has an upstream surface and a downstream surface.

In yet another embodiment, a chamber is provided. The chamber includes a support assembly and a Radio Frequency (RF) power source coupled to the diffuser. The diffuser is disposed opposite the support assembly. The diffuser includes a top diffuser plate having an upstream surface and a downstream surface and a plurality of first gas channel segments disposed in the top diffuser plate. Each first gas channel is adjacent to at least one fluid channel disposed in the top diffuser plate. Each fluid channel is connected to a supply channel disposed in the top diffuser plate, the supply channel having a supply inlet configured to be coupleable to a fluid supply conduit of the heat exchanger. Each fluid passage is connected to a return passage provided in the top diffuser plate. A return channel having a return outlet is configured to be coupleable with a fluid return conduit of the heat exchanger. The bottom diffuser plate is coupled to the top diffuser plate. The bottom diffuser plate has an upstream surface and a downstream surface.

Drawings

The above features of the present disclosure may be understood in detail with reference to the embodiments, some of which are illustrated in the accompanying drawings, and a more particular description of the disclosure briefly summarized above. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of scope, for the embodiments may admit to other equally effective embodiments.

FIG. 1 is a schematic cross-sectional view of one embodiment of a plasma enhanced chemical vapor deposition system according to one embodiment.

Fig. 2A is a partial schematic cross-sectional view and fig. 2B is a cross-sectional bottom view of an exemplary diffuser according to an embodiment.

FIG. 2C is a reverse bottom perspective view of a top diffuser plate according to one embodiment.

FIG. 2D is an enlarged reverse side section of a top diffuser plate according to one embodiment.

FIG. 2E is a reverse bottom perspective view of a top diffuser plate according to one embodiment.

FIG. 2F is an enlarged reverse side section of a top diffuser plate according to one embodiment.

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 and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

Detailed Description

Embodiments described herein provide a gas distribution assembly that improves uniformity of a deposited film or a film to be etched. Each gas distribution assembly includes one of unidirectional and bidirectional flow of fluid through the diffuser such that excess heat is removed and/or heat is provided to the diffuser to maintain a predetermined diffuser temperature. Maintaining the diffuser 105 at a predetermined diffuser temperature independent of the plasma intensity and heat radiated from the substrate support during processing results in a deposited or etched film with improved uniformity.

FIG. 1 is a schematic cross-sectional view of one embodiment of a Plasma Enhanced Chemical Vapor Deposition (PECVD) chamber 100 available from Applied Materials, Inc., of Santa Clara, Calif. It is to be understood that the system described below is an exemplary chamber and that other chambers, including chambers from other manufacturers, may be used or modified to implement aspects of the present disclosure. The chamber 100 includes a chamber body 102, a substrate support assembly 104, and a gas distribution assembly 106. The gas distribution assembly 106 is disposed opposite the substrate support assembly 104 and defines a processing volume 108 therebetween.

The substrate support assembly 104 is at least partially disposed within the chamber body 102. The substrate support assembly 104 supports a substrate 110 during processing. The substrate support assembly 104 includes a substrate support 112. The substrate support 112 has a lower surface 114 for mounting posts 118 and an upper surface 116 for supporting the substrate 110. The rod 118 couples the substrate support assembly 104 to a lift system 120 that moves the substrate support assembly 104 between a processing position (as shown) and a transfer position that facilitates transfer of substrates into and out of the chamber 100 through a slit valve 122 of the chamber body 102.

In one embodiment, which may be combined with other embodiments described herein, a resistive element (not shown) disposed in the substrate support is coupled to a supply source, such as a power source, that controllably heats the substrate support 112. In another embodiment, which may be combined with other embodiments described herein, at least one fluid channel (not shown) connected to the heat exchanger 124 is connected to the at least one fluid channel by a support supply conduit 126 connected to an inlet of the at least one fluid channel and by a support return conduit 128 connected to an outlet of the at least one fluid channel. The heat exchanger 124 circulates a fluid through the substrate support 112 such that excess heat is removed and/or heat is provided to the substrate support 112 to maintain a predetermined support temperature. The predetermined support temperature may be set to a temperature according to process parameters such that a uniform temperature distribution of the substrate 110 is maintained independent of the plasma intensity during processing. The fluid may include a material that can maintain a temperature of about 50 ℃ to about 450 ℃.

Gas distribution assembly 106 includes a diffuser 105 suspended from backing plate 103 by a hanger plate 107. A plurality of gas passages 109 are formed through the diffuser 105 to allow a uniform predetermined distribution of gas to pass through the diffuser 105 and into the processing volume 108. The hanger plate 107 maintains the diffuser 105 and backing plate 103 in a spaced apart relationship, defining a plenum (plenum)111 therebetween. The backing plate 103 includes a gas inlet channel 113, the gas inlet channel 113 is coupled to a manifold 115, and the manifold 115 may be coupled to one or more gas sources 117. The plenum 111 allows gas to be provided uniformly over the diffuser 105 and to flow across the plurality of gas channels 109 in a uniform distribution across the width of the gas distribution assembly 106 so as to flow uniformly in the processing volume 108.

The gas distribution assembly 106 is coupled to a Radio Frequency (RF) power source 119, the RF power source 119 being configured to generate a plasma for processing the substrate 110. The substrate support assembly 104 is typically grounded such that RF power is supplied to the gas distribution assembly 106 by an RF power source 119 to provide a capacitive coupling between the diffuser 105 and the substrate support 112. When RF power is supplied to the diffuser 105, an electric field is generated between the diffuser 105 and the substrate support 112 such that atoms of the gas present in the processing volume 108 between the substrate support 112 and the diffuser 105 are ionized and electrons are released. During processing, the heat generated from the plasma intensity and the heat radiated from the substrate support 112 to the diffuser 105 may not be uniform, thereby creating hot and cold zones across the diffuser 105. The gas distribution assembly 106 includes a system 101 that maintains a predetermined diffuser temperature that is uniform across the diffuser 105 independent of the plasma intensity and the heat radiated from the substrate support 112 during processing. Maintaining the diffuser 105 at a predetermined diffuser temperature independent of the plasma intensity and heat radiated from the substrate support 112 during processing produces a deposited film or an etched film with improved uniformity.

The system 101 includes at least a plurality of fluid channels 121. Each fluid channel 121 has a channel inlet (shown in fig. 2C-2F) coupled to at least one of a supply channel (shown in fig. 2C-2F) and a supply bypass channel (shown in fig. 2E and 2F). Each fluid channel 121 has a channel outlet (shown in fig. 2C-2F) coupled to at least one of a return channel (shown in fig. 2C-2F) and a return bypass channel (shown in fig. 2E and 2F). The heat exchanger 123 is connected to the supply channel by a fluid supply conduit 125 connected to the inlet of the supply channel (shown in fig. 2C and 2E). The heat exchanger 123 is connected to the return channel by a fluid return conduit 127 connected to the outlet of the return channel (shown in fig. 2C and 2E). The heat exchanger 123 circulates fluid through the fluid channel 121 so as to remove excess heat and/or provide heat to the diffuser 105 to maintain a predetermined diffuser temperature. The predetermined diffuser temperature may be set to a temperature according to process parameters such that a uniform temperature distribution of the diffuser 105 is maintained independent of the plasma intensity and the heat radiated from the substrate support 112 during processing. The fluid may include a material that can maintain a temperature of about 50 ℃ to about 450 ℃.

A controller 130 is coupled to the chamber 100 and is configured to control various aspects of the chamber 100 during processing. The controller 130 may include a Central Processing Unit (CPU) (not shown), a memory (not shown), and support circuitry (or I/O) (not shown). The CPU may be one of any form of computer processor used in an industrial environment to control various processes and hardware (e.g., motors and other hardware) and monitor processes (e.g., flow of fluids). A memory (not shown) is connected to the CPU and may be one or more of readily available memory such as Random Access Memory (RAM), Read Only Memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. Software instructions and data may be encoded and stored in memory for transmission of instructions to the CPU. Support circuits (not shown) are also connected to the CPU for supporting the processor in a conventional manner. The support circuits may include conventional cache, power supplies, clock circuits, input/output circuits, subsystems, and the like. A program (or computer instructions) readable by the controller 130 determines which tasks may be performed by the chamber 100. The program may be software readable by the controller 130 and may include instructions for monitoring and controlling, such as a predetermined diffuser temperature of the diffuser 105.

Fig. 2A is a partial schematic cross-sectional view of an exemplary diffuser 105 and fig. 2B is a cross-sectional bottom view of the exemplary diffuser. The diffuser 105 is configured to have a thickness 242 that maintains sufficient flatness across the ceiling 107 to avoid adversely affecting substrate processing. In one embodiment, which may be combined with other embodiments described herein, the thickness 242 of the diffuser 105 is between about 0.8 inches (inch) to about 2.0 inches. The diffuser 105 may be circular for semiconductor wafer fabrication, or polygonal, such as rectangular, for flat panel display fabrication.

Diffuser 105 includes a top diffuser plate 202 that includes an upstream surface 206 facing backing plate 103 and a downstream surface 208. In one embodiment, which may be combined with other embodiments described herein, the downstream surface 208 of the diffuser 105 is cast, brazed, forged, hot isostatic pressed, and sintered (using at least one of them) onto an upstream surface 210 of the base diffuser plate 204 that includes a downstream surface 212 that faces the substrate support 112. The top diffuser plate 202 has a thickness 244 and the bottom diffuser plate 204 has a thickness 246. Each gas passage 109 includes a first gas passage section 248 in the top diffuser plate 202 and a second gas passage section 250 in the bottom diffuser plate 204. In one embodiment, which may be combined with other embodiments described herein, each fluid channel 121 adjacent to an orifice 216 is a distance 240 from the orifice 216. In another embodiment, which may be combined with other embodiments described herein, each fluid channel 121 has a width 238 and a height 236. In another embodiment, which may be combined with other embodiments described herein, each fluid channel 121 is U-shaped or V-shaped.

As shown in fig. 2C (reverse bottom perspective view of the top diffuser plate 202 of the exemplary diffuser 105) and fig. 2D (enlarged reverse section of the top diffuser plate 202), each fluid channel 121 is disposed adjacent to at least one first gas channel section 248. The fluid channels 121 are formed on the downstream surface 208 of the top diffuser plate 202. Each first gas channel segment 248 is disposed in the top diffuser plate 202. As shown in fig. 2A, each first gas channel segment 248 is defined by a first bore 214 coupled with an aperture 216, and each second channel segment 250 is defined in the bottom diffuser plate 204 by a second bore 218 coupled with an aperture 216 in the top diffuser plate 202. In the embodiment shown in fig. 2C and 2D, each fluid channel 121 has a unidirectional flow configuration, and has a channel inlet 213 coupled to supply channel 207 and a channel outlet 215 coupled to return channel 209. The supply channel 207 includes an inlet 203 to be connected to the heat exchanger 123 by a fluid supply conduit 125, and an outlet 205 to be connected to the heat exchanger 123 by a fluid return conduit 127. The heat exchanger 123 circulates a unidirectional flow of fluid through the fluid channel 121 to maintain the diffuser 105 at a predetermined diffuser temperature. In one embodiment, which may be combined with other embodiments described herein, the system 101 includes a plurality of thermocouples 251 coupled to the controller 130 to determine the temperature of the diffuser 105. The controller 130, coupled to the thermocouple 251 and the heat exchanger 123, is operable to monitor and control the circulation and temperature of the fluid entering the supply channel 207.

The first bore 214, the aperture 216, and the second bore 218 combine to form a path through the diffuser 105. The first bore 214 extends a first length 230 from the upstream surface 206 of the top diffuser plate 202 to a bottom 220. The bottom 220 of the first bore 214 may be tapered, beveled, chamfered, or rounded to minimize flow restriction as gas flows from the first bore 214 into the aperture 216. The first bore 214 generally has a diameter of about 0.093 inches to about 0.218 inches, and in one embodiment about 0.156 inches.

The second bore 218 is formed in the bottom diffuser plate 204 and extends a third length 234 of about 0.10 inches to about 2.0 inches from the downstream surface 212. Preferably, the third length 234 is between about 0.1 inches and about 1.0 inches. The diameter 226 of the second bore 218 is generally about 0.1 inches to about 1.0 inches and may be flared at an angle 224 of about 10 degrees to about 50 degrees. Preferably, the diameter 226 is between about 0.1 inches and about 0.5 inches and the angle 224 is between 20 degrees and about 40 degrees. The diameter 226 of the second bore 218 refers to the diameter that intersects the downstream surface 212. The surface area of the second bore 218 is between about 0.05 square inches and about 10 square inches and preferably between about 0.05 square inches and about 5 square inches. 214

An example of a diffuser 105 for processing 1500mm x1850 mm substrates has a second bore 218 with a diameter 226 of 0.250 inches and an angle 224 of about 22 degrees. The distance 228 between the edges 252 of adjacent second bores 218 is between about 0 inches and about 0.6 inches, preferably between about 0 inches and about 0.4 inches. The diameter 254 of the first bore 214 is typically, but not limited to, at least equal to or less than the diameter 226 of the second bore 218. The bottom 222 of the second bore 218 may be tapered, beveled, chamfered, or rounded to minimize pressure loss of gas flowing out of the orifice 216 and into the second bore 218.

The aperture 216 generally couples a bottom 220 of the first bore 214 with a bottom 222 of the second bore 218. The orifice 216 generally has a diameter of about 0.01 inch to about 0.3 inch, preferably about 0.01 inch to about 0.1 inch, and typically has a second length 232 of about 0.02 inch to about 1.0 inch, preferably about 0.02 inch to about 0.5 inch. The second length 232 and diameter (or other geometric attributes) of the orifices 216 are the primary sources of backpressure in the plenum 111 that promotes uniform gas distribution across the entire upstream surface 206 of the top diffuser plate 202. The orifices 216 are typically uniformly arranged among the plurality of gas passages 109; however, the restriction through the orifice 216 may be configured differently among the plurality of gas passages 109 to facilitate more gas flow through one region of the diffuser 105 than another region. For example, the apertures 216 in those gas passages 109 of the diffuser 105 that are closer to the wall of the chamber body 102 may have a larger diameter and/or a shorter second length 232 to flow more gas across the edge of the diffuser 105 to increase the deposition rate at the periphery of the substrate 110. The diffuser plate has a thickness of between about 0.8 inches and about 3.0 inches, preferably between about 0.8 inches and about 2.0 inches.

As shown in fig. 2E, a reverse bottom perspective view of a top diffuser plate 202 having a bi-directional flow configuration, shown in an enlarged reverse section, and fig. 2F. The bi-directional flow configuration includes a first portion of the plurality of fluid channels 121 having a channel inlet 211 coupled to the supply channel 207 and a channel outlet 249 coupled to the return channel 209. The bi-directional flow configuration includes a second portion of the plurality of fluid passages 121 having a passage inlet 211 coupled to the supply bypass passage 217 and a passage outlet 249 coupled to the return bypass passage 219. The supply bypass channel 217 is coupled with the supply channel 207 by a supply transfer channel 221. The return bypass passage 219 is coupled to the return passage 209 by a return transfer passage 223. The first and second portions of the fluid channel 121 alternate for bi-directional flow of fluid. The heat exchanger 123 circulates fluid through the supply passage 207, a first portion of the plurality of fluid passages 121, and the return passage 209, and through the supply bypass passage 217, a second portion of the plurality of fluid passages 121, and through the return bypass passage 219 to maintain the diffuser 105 at a predetermined diffuser temperature.

In summary, gas distribution assemblies are described herein that improve the uniformity of a deposited film or a film to be etched. Each gas distribution assembly includes one of unidirectional and bidirectional flow of fluid through the diffuser such that excess heat is removed and/or heat is provided to the diffuser to maintain a predetermined diffuser temperature. Maintaining the diffuser at a predetermined diffuser temperature independent of the plasma intensity and the heat radiated by the substrate support during processing produces a deposited or etched film with improved uniformity.

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

Claims

1. A diffuser, comprising:

a top diffuser plate having an upstream surface and a downstream surface;

a plurality of first gas channel segments disposed in the top diffuser plate, each first gas channel adjacent to at least one fluid channel disposed in the top diffuser plate, wherein:

each fluid channel is connected to a supply channel disposed in the top diffuser plate, the supply channel having a supply inlet configured to be coupleable to a fluid supply conduit of a heat exchanger; and is

Each fluid channel is connected to a return channel disposed in the top diffuser plate, the return channel having a return outlet configured to be coupleable with a fluid return conduit of the heat exchanger; and

a bottom diffuser plate coupled with the top diffuser plate, the bottom diffuser plate having an upstream surface and a downstream surface.

2. The diffuser of claim 1, wherein each first gas passage section comprises a first bore coupled with an orifice, and wherein each second gas passage section comprises a second bore coupled with the orifice of the top diffuser plate.

3. The diffuser of claim 2, wherein each orifice is adjacent to at least one fluid passage disposed in the top diffuser plate.

4. A diffuser according to claim 3, wherein each fluid channel adjacent to the aperture is a first distance from the aperture.

5. The diffuser of claim 1, wherein when the heat exchanger is coupled with the supply channel and the return channel, the heat exchanger is operable to circulate fluid from the fluid supply conduit, through the supply channel, each fluid channel, the return channel, and through the fluid return conduit to the heat exchanger.

6. A diffuser according to claim 5, wherein a controller coupled to the heat exchanger is operable to control circulation of the fluid to maintain a predetermined diffuser temperature.

7. The diffuser of claim 6, wherein a thermocouple disposed in the top diffuser plate is coupled to the controller.

8. The diffuser of claim 1, wherein the downstream surface of the top diffuser plate is used in at least one of the following ways: casting, brazing, forging, hot isostatic pressing, and sintering onto the upstream surface of the bottom diffuser plate.

9. The diffuser of claim 1, wherein the diffuser is positionable in a processing chamber opposite a substrate support positioned in the processing chamber.

10. A diffuser, comprising:

a top diffuser plate having an upstream surface and a downstream surface;

each fluid channel is connected to one of a supply channel and a supply bypass channel disposed in the top diffuser plate, the supply channel having a supply inlet configured to be coupleable with a fluid supply conduit of a heat exchanger, the supply bypass channel being in fluid communication with the supply channel; and is

Each fluid channel is connected to one of a return channel and a return bypass channel disposed in the top diffuser plate, the return channel having a return outlet configured to be coupleable with a fluid return conduit of the heat exchanger, the return bypass channel being in fluid communication with the return channel; and

11. A chamber, comprising:

a support assembly; and

a Radio Frequency (RF) power source coupled to a diffuser disposed opposite the support assembly, the diffuser comprising:

a top diffuser plate having an upstream surface and a downstream surface;

12. The chamber of claim 11, wherein when the heat exchanger is coupled with the supply channel and the return channel, the heat exchanger is operable to circulate fluid from the fluid supply conduit, through the supply channel, each fluid channel, the return channel, and through the fluid return conduit to the heat exchanger.

13. The chamber of claim 12, wherein a controller coupled with the heat exchanger is operable to control circulation of the fluid to maintain a predetermined diffuser temperature.

14. The chamber of claim 13, wherein a thermocouple disposed in the top diffuser plate is coupled to the controller.

15. The chamber of claim 11, wherein the downstream surface of the top diffuser plate is used in at least one of the following ways: casting, brazing, forging, hot isostatic pressing, and sintering onto the upstream surface of the bottom diffuser plate.