Sensor assembly, edge ring metric measurement system, and semiconductor processing system for determining a position of a ring within a process kit

Abstract

The examples disclosed herein relate to methods and apparatus for determining the position of a ring within a processing suite. In one example, a sensor assembly for a substrate processing chamber is provided. The sensor assembly includes a housing having a top surface, a bottom surface opposite the top surface, and a plurality of sidewalls connecting the top surface to the bottom surface. The housing also has a recess in the top surface that forms an internal volume within the housing. The sensing assembly includes a biasing member and a contact member disposed on the biasing member. The biasing member and the contact member are disposed within the recess. The sensor is configured to detect displacement of the contact member. The displacement of the contact member corresponds to the relative position of the edge ring.

Description

[Technical Field]

[0001] The examples disclosed herein relate to methods and apparatus for determining the position of a ring within a processing suite. [Previous Technology]

[0002] As semiconductor technology nodes advance with the reduction of device geometry, the requirements for critical dimension uniformity at substrate edges become more stringent and affect wafer yield. During deposition or etching, processing kits containing multiple rings are provided to advantageously influence the uniformity of the substrate periphery or edge. Depending on the edge ring geometry, the plasma sheath can be bent at the substrate edge, allowing ions to be accelerated perpendicular to the plasma sheath.

[0003] Routine maintenance requires that components exposed to harsh plasma environments undergo periodic measurement and testing to determine whether rings meet original specifications and whether maintenance or replacement is necessary. Ensuring that replacement rings meet specifications and are in the correct position requires the use of measurement and testing techniques. Common methods for determining edge ring position include mechanical and optical manipulation.

[0004] Non-contact techniques include using interferometry (where light is projected onto the surface of a processing kit ring) and comparing the difference between incident and refracted light. When two light waves of the same frequency combine, the resulting intensity pattern is determined by the phase difference between the two waves. Destructive interference occurs when the light waves are out of phase. Other known control methods include using mechanical measurements, such as calipers or styluses. For example, a stylus has a tip that is dragged to contact the surface of the ring, and as the tip encounters peaks and valleys, the tip rises and falls as the ring is leveled relative to a substrate support. The amount by which the stylus rises or falls at any given point corresponds to the compliance of the ring with the ring's original parameters.

[0005] The substrate placed on the substrate support may undergo processes of depositing material onto the substrate and removing or etching portions of the material from the substrate, typically in a continuous or alternating manner. Processing non-uniformities are often present on the surface of the substrate and may be noticeable at the periphery or edges of the substrate, especially when a ring of the processing kit is not properly aligned. These peripheral non-uniformities can be attributed to undesirable electric field termination effects.

[0006] Therefore, there is a need for an improved method and apparatus for indicating the position of the edge ring before and after maintenance or replacement. [Summary of the Invention]

[0007] The examples disclosed herein relate to methods and apparatus for determining the position of a ring (e.g., an edge ring) within a processing kit. In one example, a sensor assembly for a substrate processing chamber is provided. The sensor assembly includes a housing having a top surface, a bottom surface opposite the top surface, and a plurality of sidewalls connecting the top surface to the bottom surface. The housing also has a recess in the top surface that forms an internal volume within the housing. The sensing assembly includes a biasing member and a contact member disposed on the biasing member. The biasing member and the contact member are disposed within the recess. The sensor is configured to detect displacement of the contact member. The displacement of the contact member corresponds to the relative position of the edge ring.

[0008] In another example, an edge ring metric measurement system is provided. The edge ring metric measurement system includes an edge ring disposed on a substrate support surface and a housing. The housing has a top surface, a bottom surface opposite the top surface, and a plurality of sidewalls connecting the top surface to the bottom surface. The housing also includes a recess in the top surface. The recess forms an internal volume within the housing. The edge ring metric measurement system includes a biasing member and a contact member disposed on the biasing member. The biasing member and the contact member are disposed within the recess. An alignment pin mechanically contacts the edge ring and the contact member. A light emission sensor is configured to detect displacement of the contact member. The displacement of the contact member corresponds to the metric of the edge ring.

[0009] Another example of the present invention provides a semiconductor processing system including a processing chamber configured to process a substrate. A non-transitory computer-readable medium stores instructions that, when executed by a processor, cause a method to be performed in the processing chamber. The method includes receiving a signal at a sensor. The signal is emitted below a substrate support surface configured to have an edge ring disposed thereon. The edge ring is configured to surround the substrate. The method further includes detecting displacement of the edge ring and calculating a metric of the edge ring based on the displacement. The method further includes performing a maintenance operation on the edge ring in response to the metric.

[0010] For clarity, the same element symbols are used where applicable to denote the same elements common to the figures. Furthermore, an element of one example may be advantageously applied to other examples described herein.

Implementation Method

[0018] The examples disclosed herein relate to methods and apparatus for determining the position of a ring within a processing kit. The methods and apparatus disclosed herein enable the determination of the position of a processing kit ring when it is concealed and cannot be directly monitored optically, and when space available for a sensor is limited. A processing kit may include several rings, including one or more edge rings near the edge of a substrate support surface, one or more tuning rings located below the edge rings and in physical contact with the edge rings, and sliding rings near the tuning rings or edge rings. During multiple processing operations, debris from the substrate, processing kit, or other chamber components may accumulate and adhere to the surface of one or more rings of the processing kit. During maintenance, when one of the rings is removed, replaced, or repositioned, the accumulated debris can cause the tuning ring or edge ring to wed between adjacent rings or processing chamber surfaces. Wedging of the processing kit ring can cause the edge rings to become misaligned with the substrate support, thus adversely affecting the plasma sheath.

[0019] The methods and apparatus disclosed herein utilize an alignment device to monitor the position of a measured ring within a processing suite. The alignment device includes an alignment pin, a sensor, a housing with a transparent window, a biasing member, and a contact member (e.g., a disc) configured to contact the alignment pin. The alignment pin contacts a tuning ring, which in turn contacts one or more edge rings. When the alignment pin retracts from the substrate surface, any processing suite ring may wedge into another ring of the processing suite, causing that ring to tilt upwards. Conventional methods and apparatus for determining the position of edge rings include using a camera, laser, or sensor to determine the position of the edge rings through a window in the processing chamber. However, conventional methods require a line of sight between the sensor and the desired ring in the processing suite, thus limiting the tools available for determining the position of edge rings. Furthermore, plasma and RF frequencies within the chamber can interfere with sensor readings, thus requiring additional components and methods to eliminate noise in the collected signals.

[0020] Therefore, the methods and apparatus disclosed herein use lasers to determine the deflection of the contact members (i.e., discs) coupled to the alignment pins, which makes it possible to determine the position of one or more processing kit rings. In one example, the weight of the edge rings can be determined using the methods and apparatus disclosed herein, along with a force sensor or torque motor and screws. Advantageously, replacement and maintenance of the alignment pins are simplified because the alignment pins can be removed through holes in the processing kit without removing the substrate support. Furthermore, the size of the holes through which the alignment pins pass is kept sufficiently small to substantially prevent arcing that could potentially damage other processing chamber components. One advantage of placing the sensors outside the processing chamber is that signal strength and quality can be maintained. Therefore, interference from electromagnetic waves and high temperatures within the processing chamber does not reduce the reliability of sensor measurements by introducing distorted sensor signals.

[0021] FIG1 is a schematic cross-sectional view of a processing chamber 100 having a substrate support assembly 180 according to an example. As shown, the processing chamber 100 is an etching chamber suitable for etching a substrate 150. Examples of processing chambers suitable for benefiting from the present disclosure include Sym3® processing chambers, C3® processing chambers, and Mesa™ processing chambers, which are commercially available from Applied Materials, Inc., located in Santa Clara, California. Other processing chambers, including deposition chambers and processing chambers from other manufacturers, are contemplated to be suitable for benefiting from the present disclosure.

[0022] The processing chamber 100 includes a chamber body 101 and a cover 103 disposed thereon, which together define an internal volume 130. The chamber body 101 is coupled to an electrical ground 107. A substrate support assembly 180 is disposed within the internal volume 130 to support a substrate 150 thereon during processing. The processing chamber 100 also includes an inductively coupled plasma device 102 for generating plasma within the processing chamber 100. A controller 155 is adapted to control the processing chamber 100.

[0023] The substrate support assembly 180 includes one or more electrodes 153 coupled to a bias source 119 via a matching network 120 to facilitate biasing of the substrate 150 during processing. The bias source 119 may illustratively be a source of RF energy up to about 1,000 W (but not limited to about 1,000 W) at a frequency of, for example, about 13.56 MHz, although other frequencies and powers may be provided as needed for a particular application. The bias source 119 may be capable of generating one or both continuous or pulsed power. In some examples, the bias source 119 may be a DC or pulsed DC source. In some examples, the bias source 119 may be capable of providing multiple frequencies. One or more electrodes 153 may be coupled to a clamping power supply 162 to facilitate clamping of the substrate 150 during processing.

[0024] An inductively coupled plasma device 102 is disposed above the cover 103 and configured to inductively couple RF power into the processing chamber 100 to generate plasma within the processing chamber 100. The inductively coupled plasma device 102 includes first and second coils 110, 112 disposed above the cover 103. The relative position, diameter ratio, and / or number of turns in each coil 110, 112 can be adjusted as needed to control the distribution or density of the plasma being formed. Each of the first and second coils 110, 112 is coupled to an RF power supply 108 via a matching network 114 through an RF feed structure 106. The RF power supply 108 can illustratively generate up to about 4,000 W (but not limited to about 4,000 W) at an adjustable frequency in the range of 50 kHz to 13.56 MHz, although other frequency and power-specific applications may be used as needed. In some examples, a power divider 105, such as a voltage divider capacitor, may be provided between the RF feed structure 106 and the RF power supply 108 to control the relative amount of RF power supplied to the respective first and second coils 110, 112. In some examples, the power divider 105 may be incorporated into the matching network 114.

[0025] A heating element 113 may be disposed on top of the cover 103 to facilitate heating of the interior of the processing chamber 100. The heating element 113 may be disposed between the cover 103 and the first and second coils 110, 112. In some examples, the heating element 113 may include a resistance heating element and may be coupled to a power source 115 (e.g., AC power) configured to provide sufficient energy to control the temperature of the heating element 113 within a desired range.

[0026] During operation, a substrate 150 (e.g., a semiconductor wafer or other substrate suitable for plasma processing) is placed on a substrate support surface 182 of a substrate support assembly 180. Process gas is supplied from a gas panel 116 through an inlet 117 into the internal volume 130 of the chamber body 101. The process gas is ignited into plasma 118 within the processing chamber 100 by applying power from an RF power supply 108 to the first and second coils 110, 112. In some examples, power from a bias source 119, such as an RF or DC source, may also be supplied to electrodes 153 within the substrate support assembly 180 via a matching network 120. The pressure inside the processing chamber 100 can be controlled using a valve 121 and a vacuum pump 122. The temperature of the chamber body 101 can be controlled using a liquid-containing conduit (not shown) extending through the chamber body 101.

[0027] The processing chamber 100 can be used for various plasma processes. In one example, the processing chamber 100 can be used to perform dry etching with one or more etchants. For example, the processing chamber 100 can be used to ignite the plasma from one or more precursors or process gases, such as one or more fluorocarbons (e.g., CF4 or C2F6), O2, NF3, N2, Ar, He, or combinations thereof.

[0028] Processing chamber 100 includes a controller 155 to control the operation of processing chamber 100 during processing. Controller 155 may include processor 123, memory 124, and support circuitry 125 for processor 123 and components that facilitate control of processing chamber 100. Controller 155 may be one of any type of general-purpose computer processor that can be used in an industrial environment to control various chambers and subprocessors. Memory 124 stores software (source code or target code) that can be executed or invoked to control the operation of processing chamber 100 in the manner described herein. Memory 124 is non-transient and may be one or more readily available memories, such as random access memory (RAM), read-only memory (ROM), or any other form of regional or remote digital storage. Memory 124 contains instructions that, when executed by processor 123, facilitate the execution of method 500 (as shown in FIG. 5).

[0029] To facilitate control of the processing chamber 100, the processor 123 can be any form of general-purpose computer processor or general-purpose central processing unit (CPU), each of which can be used in an industrial environment, for example as a programmable logic controller (PLC), for controlling various chambers and subprocessors. Memory 124 is coupled to the processor 123 and is non-transient and can be one or more types of readily available memory, such as random access memory (RAM), read-only memory (ROM), floppy disk drive, hard disk, or any other form of regional or remote digital storage. Support circuitry 125 is coupled to the processor 123 for supporting the processor in a conventional manner. The generation, heating, and other processing of charged matter are typically stored in memory 124, typically as software routines. Software routines can also be stored and / or executed by a second CPU (not shown) remote from the processing chamber 100 controlled by the processor 123.

[0030] Memory 124 is in the form of a computer-readable storage medium containing instructions that, when executed by processor 123, facilitate the operation of processing chamber 100. The instructions in memory 124 are in the form of a program product, such as a program implementing the methods of this disclosure. The program may conform to any of a variety of different programming languages. In one example, this disclosure may be implemented as a program product stored on a computer-readable storage medium for use by a computer system. The program product defines the functionality of examples (including the methods described herein). Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only storage devices within a computer, such as CD-ROM disks, flash memory, ROM chips, or any type of solid-state non-volatile semiconductor memory that can be read by a CD-ROM drive) where information is permanently stored; and (ii) writable storage media (e.g., floppy disks or any type of solid-state random access semiconductor memory in a floppy disk drive or hard disk drive) where modifiable information is stored. Such computer-readable storage media are examples of this disclosure when carrying computer-readable instructions that direct the functionality of the methods described herein.

[0031] FIG2 shows an enlarged partial cross-sectional view of a processing kit 200 disposed on a substrate support assembly 180 in the processing chamber 100 of FIG1. ​​The processing chamber 100 also includes a processing kit 200 disposed in an internal volume 130, for example on the substrate support assembly 180. The processing kit 200 is used during plasma processing of the substrate 150.

[0032] The substrate support assembly 180 includes an electrostatic clamp (ESC) 202, a cooling plate (or cathode) 204, a base 206, and a cathode stack 212. The cooling plate 204 is disposed on the base 206. The cooling plate 204 may include a plurality of cooling channels (not shown) for circulating coolant through it. The cooling plate 204 may be engaged or bonded to the electrostatic clamp 202 by an adhesive or other suitable mechanism. One or more power sources 208 may be coupled to the cooling plate 204. The power sources may be or include sources and / or feeds for RF (RF), alternating current (AC), and / or direct current (DC). The electrostatic clamp 202 may include one or more heaters (not shown). The one or more heaters may be independently controllable. The one or more heaters enable the electrostatic clamp 202 to heat the substrate 150 to a desired temperature.

[0033] The processing kit 200 includes an edge ring 210 having a first ring component 220 and a second ring component 230, each ring component forming an annular body. Therefore, the edge ring 210 is a ring of the processing kit 200, which includes a plurality of rings, such as the first ring component 220 and the second component 230. Furthermore, the edge ring 210 is wholly or partially disposed on the substrate support surface 182. The first ring component 220 and the second ring component 230 may be independently made of or include one or more electrically insulating materials, such as silicon carbide, silicon oxide, quartz, or any combination thereof. The two ring components 220, 230 engage with each other such that the second ring component 230 is movable relative to the first ring component 220. The height of the first ring component 220 is substantially the same as the height of the electrostatic clamp 202. Thus, the first ring component 220 protects one side of the electrostatic clamp 202. In some examples, when the substrate 150 is positioned on the electrostatic clamp 202, it extends partially over a portion of the first ring member 220.

[0034] The processing kit 200 also includes an adjustable tuning ring 250 having an upper surface 254 and a lower surface 256. The adjustable tuning ring 250 may be formed of or otherwise include one or more conductive materials. For example, the conductive material may be or include aluminum or one or more aluminum alloys. The adjustable tuning ring 250 is disposed below the edge ring 210. For example, the adjustable tuning ring 250 is disposed below the second ring member 230. The adjustable tuning ring 250 contacts the lower surface 231 of the second ring member 230. In one example, the adjustable tuning ring 250 extends downward along the length of the electrostatic clamp 202 and the cooling plate 204, such that the adjustable tuning ring 250 has a height substantially equal to the combined height of the electrostatic clamp 202 and the cooling plate 204. Therefore, the adjustable tuning ring 250 is capable of coupling power from the cooling plate 204 to the edge ring 210.

[0035] The adjustable tuning ring 250 may surround the cooling plates 204, thereby forming a laterally spaced gap 258 between them. In one example, the laterally spaced gap 258 has a width greater than 0 inches and less than or equal to 0.03 inches. In other examples, the width of the laterally spaced gap 258 is about 0.005 inches, about 0.007 inches, or about 0.009 inches to about 0.0010 inches, about 0.0013 inches, about 0.0015 inches, or about 0.0019 inches. For example, the laterally spaced gap 258 has a width of about 0.007 inches to about 0.0015 inches. The adjustable tuning ring 250 abuts against the alignment pin 260. Thus, the alignment pin 260 mechanically contacts the adjustable tuning ring 250.

[0036] The processing kit 200 also includes a cap ring assembly 270, an annular body 276, and a plasma curtain 278 at least partially disposed therebetween. The cap ring assembly 270 has an annular shape and includes a cap ring 272 and a sleeve 274. The cap ring 272 and the sleeve 274 may be made of or comprise quartz or other plasma-resistant materials independently. For example, the cap ring 272 may be a quartz ring, and the sleeve 274 may be a quartz tube.

[0037] Figure 3 illustrates an alignment assembly 300 configured to obtain a measurement of a ring (e.g., edge ring 210) of the processing kit 200. In one example, the measurement obtained by the alignment assembly 300 is the weight of the edge ring 210. The alignment assembly 300 includes a housing 302, a sensor 304 disposed below the housing 302, and an alignment pin 260 extending into the housing 302. The sensor 304 is configured to emit and receive a light beam 301. The alignment assembly 300 is coupled to a base 306 of a substrate support assembly 180. A hole 310 is provided in the base 306, which allows the alignment pin 260 to extend unobstructed through the base 306. A guide 308 may be disposed in the hole 310 to provide a bearing surface to facilitate axial movement while preventing the alignment pin 260 from wandering or moving horizontally. Although one alignment assembly 300 is illustrated, it is contemplated that up to three alignment assemblies 300 may be arranged around the substrate support assembly 180 at 120-degree intervals.

[0038] In one example, the beam 301 of sensor 304 has a frequency from about 500 nm to about 1000 nm. The beam diameter of beam 301 may be from about 25 to about 75 micrometers. In another example, beam 301 may have an optical frequency from about 600 nm to about 750 nm. Exemplary frequencies include, but are not limited to, frequencies of about 550 nm, about 650 nm, about 700 nm, and about 750 nm. Sensor 304 is used to emit beam 301 and detect the return of beam 301. Therefore, sensor 304 is able to determine the distance that beam 301 has traveled. For example, sensor 304 may detect the time of flight of beam 301. Alignment pin 260 has an upper end 303 that contacts the lower surface 256 of adjustable tuning ring 250. The lower end 305 of alignment pin 260 is configured to move the bias member 424 shown in FIG. 4.

[0039] A lifting assembly 312 is disposed in the substrate support assembly 180. In one example, the lifting assembly 312 is configured to move the edge ring 210 between raised and lowered positions (as shown in FIG. 2). In the lowered position, the edge ring 210 may be partially disposed on or near the cover ring assembly 270. As noted, the edge ring 210 may also be fully or partially disposed on the substrate support surface 182. The lifting assembly 312 is a mechanism for precisely controlling the height of the edge ring 210 above the substrate 150, thereby resulting in control of the plasma sheath and etching profile at the extreme edges of the substrate 150. Although one lifting assembly 312 is shown, it should be understood that the substrate support assembly 180 has three lifting assemblies 312 disposed within the substrate support assembly 180, each capable of balancing and moving the edge ring 210. The lifting assembly 312 has a motor 314, a bellows 316, and a lifting pin 318. Each lifting assembly 312 may be arranged approximately 120 degrees apart. In another example, the lifting assembly 312 is configured to move a shielding ring (not shown) between a raised position and a lowered position. The shielding ring is configured to cover the edge ring 210.

[0040] Motor 314 is operable to move lifting pin 318 up and down between raised and lowered positions. Motor 314 may be a linear actuator, pneumatic, hydraulic, stepper, servo, gear, or other suitable motor for providing vertical displacement of lifting pin 318. Motor 314 may be configured with a hard stop and an optical encoder for determining the stroke or movement of lifting pin 318. The optical encoder is configured to provide feedback to the controller for the precise vertical position of lifting pin 318. The optical encoder allows precise control of motor 314 to position the shielding ring (not shown) of cover ring assembly 270 supported by lifting pin 318. In one example, bellows 316 is configured to accommodate a vertical movement of lifting pin 318 of two inches (2”) or more. Bellows 316 maintains an hermetically sealed seal around lifting pin 318, allowing lifting pin 318 to move up and down while the interior of processing chamber 100 is maintained under vacuum pressure.

[0041] The lifting assembly 312 is coupled to the base frame 306. A hole 310 is provided in the base frame 306 to allow the lifting pin 318 to extend through the base frame 306 without obstruction. A guide 308 facilitates axial movement of the lifting pin 318. The guide 308 may be a bushing to prevent the lifting pin 318 from swinging or moving. The guide 308 may be formed of a ceramic material having an inner diameter to accommodate the axial movement of the lifting pin 318 via the guide 308.

[0042] Figure 4 is a cross-sectional view of the aligned assembly 300, showing details of the housing 302. The housing 302 includes a body 401, a top surface 404, a bottom surface 406 opposite to the top surface 404, and a sidewall 402 connecting the top surface 404 and the bottom surface 406. A transparent window 408 has a top surface 410 and a bottom surface 412. A plurality of fasteners 414 pass through holes in the transparent window 408 into the body 401 of the housing 302 and secure the transparent window 408 to the housing 302. The fasteners 414 pass through the bottom surface 406 of the body 401 but do not extend through the top surface 404. An O-ring 416 may be recessed into the body 401 between the bottom surface 406 of the housing 302 and the top surface 410 of the transparent window 408.

[0043] In one example, the transparent window 408 is made of transparent ceramic or transparent crystal. For example, the transparent window 408 may be made of plastic, glass, or sapphire. The housing 302 may be made of ceramic, metal, or composite material. In one example, the housing 302 is made of a material including aluminum.

[0044] An alignment hole 418 is provided in the top surface 404 of the body 401. The alignment hole 418 is located at the center of the body 401. The alignment hole 418 allows the alignment pin 260 to contact the contact member 422. The lower end 305 of the alignment pin 260 contacts the contact member 422. The contact member 422 and the biasing member 424 are provided in a recess 420 of the body 401. The recess 420 extends through the top surface 404. An exhaust passage 426 is equidistant from and radially disposed from the alignment hole 418. The exhaust passage 426 allows air in the recess 420 to pass through the top surface 404 of the body 401. The biasing member 424 is located in the recess 420 such that the biasing member 424 is located between the contact member 422 and the transparent window 408. The biasing member 424 is adjacent to the transparent window 408. The dimensions of the bias member 424 and the contact member 422 are designed such that the beam 301 can travel unobstructed between the sensor 304 and the contact member 422. For example, the diameters and heights of the bias member 424 and the contact member 422 are configured to fit within the recess 420, while allowing the beam 301 to pass through the transparent window 408, strike the contact member 422, and return to the sensor 304 without obstruction by the bias member 424, the contact member 422, or the inner surface of the body 401.

[0045] When the contact member 422 is biased toward the bottom surface 406, the exhaust passage 426 prevents unfavorable pressure build-up or pressure drop within the recess 420. When the contact member 422 is biased toward the top surface 404 and returns to its steady-state position, the exhaust passage 426 also allows air to enter the recess 420. Therefore, the exhaust passage 426 and the recess 420 are fluidly connected to the processing chamber 100. Fluidly coupling the exhaust passage 426 and the recess 420 to the processing chamber 100 significantly reduces pressure variations within the recess 420 that would otherwise add an undesirable force component to the bias member 424, resulting in an error in the actual displacement relative to the contact member 422. Furthermore, the exhaust passage 426 allows the recess 420 to have the same pressure as the processing chamber 100.

[0046] In one example, the bias member 424 has a spring constant greater than 2.75 psi and less than 5.0 psi. In another example, the bias member 424 has a spring constant between about 2.5 psi and about 4.5 psi, for example, between about 3.0 psi or about 4.0 psi. Exemplary spring constants include spring constants of about 2.75 psi, about 3.0 psi, and about 3.25 psi.

[0047] A through-hole 428 extending through the body 401 is aligned with a through-hole 428 extending through the transparent window 408. The through-hole 428 allows the housing 302 to be connected to the processing chamber via a fastener similar to fastener 414. The through-hole 428 also allows the sensor 304 to be mechanically coupled to the housing 302. The sensor 304 is shown in Figures 3 and 4, and its mechanical coupling to the housing 302 is not shown to show the details of the alignment assembly 300. However, it should be understood that in one example, the sensor 304 and the housing 302 are arranged such that the relative movement between the sensor 304 and the housing 302 is fixed. Therefore, in one example, the sensor 304 is fixed to the housing 302. In another example, the sensor 304 is not directly fixed to the housing 302, but may be fixed to the chamber body 101 adjacent to the sensor 304.

[0048] Figure 5 is a flowchart of a method 500 for measuring the edge ring using the alignment assembly 300. Method 500 determines the position of the processing kit by measuring the displacement of a measuring disc (e.g., contact member 422, which is mechanically coupled to the processing kit). Therefore, method 500 is configured to determine whether the edge ring of the processing kit is tilted, i.e., whether the position of the edge ring relative to the substrate support is within specifications. Alternatively or additionally, method 500 can determine edge ring wear based on the height of the edge ring relative to the substrate support.

[0049] In operation 502, a signal is received from a sensor located below the edge ring. The sensor may be a light emission sensor, such as sensor 304. The sensor is located at one end of an alignment pin. The other end of the alignment pin is in mechanical contact with the edge ring and is configured to move the edge ring in a vertical direction relative to the substrate support surface. For example, sensor 304 is positioned near the lower end 305 of alignment pin 260. The upper end 303 of alignment pin 260 contacts the lower surface 231 of adjustable tuning ring 250. Edge ring 210 (including a first ring component 220 and a second ring component 230) is disposed on top of adjustable tuning ring 250. Sensor 304 is located below each adjustable tuning ring 250 and edge ring 210, including the first ring component 220 and the second ring component 230.

[0050] In operation 504, the position of the edge ring is determined based on the signal received from the sensor. An alignment pin mechanically contacts a bias member disposed within the housing. The alignment pin is coupled to the bias member via a contact member, such that the contact member is positioned between the bias member and the alignment pin. A load on the alignment pin causes the contact member to move in the direction of gravity. The load on the alignment pin includes the weight of the edge ring, and any intermediate rings between the sensor and the edge ring, such as a tuning ring. For example, the load on alignment pin 260 includes the weight of edge ring 210, including first ring component 220 and second ring component 230, and adjustable tuning ring 250.

[0051] The relative displacement of the contact members corresponds to the load on the lifting pin. Therefore, the position of the edge ring relative to the substrate support surface corresponds to the relative displacement of the contact members. As described above, the sensor detects the relative movement of the contact members. Because the contact members are mechanically coupled to the edge ring, the sensor is able to determine the displacement of the edge ring and / or the tuning ring.

[0052] Method 500 proceeds to operation 506, where a metric of the edge ring is calculated based on the displacement of the alignment pin. In one example, the displacement of the alignment pin is used to calculate the position of the edge ring relative to the substrate support surface. The alignment pin mechanically contacts the edge ring such that the load on the alignment pin includes the weight of the edge ring, as described above. The position of the contact member is calibrated such that the sensor detects zero displacement of the contact member when the top surface of the edge ring is substantially parallel to the substrate support surface. Zero displacement of the contact member corresponds to a ring, such as the edge ring, at a level relative to the substrate support. Therefore, negative displacement of the contact member corresponds to an edge ring that is too low relative to the substrate support surface, and positive displacement of the contact member corresponds to an edge ring that is too high relative to the substrate support surface.

[0053] In a non-limiting example, sensor 304 receives a light beam 301 reflected from contact member 422. Sensor 304 is configured to determine the distance the light beam 301 has traveled, which corresponds to the displacement of contact member 422. The time of flight of the light beam 301 is determined, which corresponds to the displacement of contact member 422. The displacement of contact member can also be determined by measuring the time of flight tof of the light beam 301 during its round trip from sensor 304 to contact member 422 and back to sensor 304. The time of flight is represented by an equation. The variable t represents the time of flight, v represents the velocity of the light beam 301, and d represents the distance between sensor 304 and contact member 422. The light beam 301 is detected at sensor 304 and sent as a signal to controller 155. Controller 155, on which a program is mounted, calculates the position of contact member 422, which corresponds to the displacement of alignment pin 260.

[0054] In another example, the metric is calculated to correspond to the erosion of the edge ring. As noted, sensor 304 detects the relative position of edge ring 210 with respect to substrate support surface 182 based on the displacement of contact member 422. Therefore, as edge ring 210 is eroded, the load on alignment pin 260 decreases proportionally to the reduction in weight of the eroded edge ring 210. By monitoring the load on edge ring 210 over a period of time, the erosion rate and absolute erosion, i.e., the metric corresponding to the weight loss of edge ring 210, can be calculated.

[0055] For example, a force sensor (not shown) may be coupled to a movable portion of the alignment assembly 300 to measure the mass of the processing kit. Mechanical forces (e.g., the load or weight of the edge ring) are converted into measurable electrical signals. As the force exerted by the edge ring on the force sensor increases or decreases, the electrical signal changes proportionally. As the edge ring erodes, the mechanical force applied to the force sensor decreases, and the electrical signal output by the force sensor also decreases. The electrical signal corresponds to the wear or deterioration of the edge ring.

[0056] Alternatively, a torque motor (not shown) and a screw (e.g., alignment pin 260) are calibrated to detect the weight of the edge ring. The torque motor and screw are coupled to a processing kit, with the screw contacting the ring of the processing kit. The screw is configured to move vertically as the weight of the edge ring changes. The force required to move the processing kit is converted into an electrical signal. An encoder, such as an optical encoder, is configured to provide feedback to a controller for the precise vertical position of the screw. In one example, an optical encoder may be coupled to the torque motor. The electrical signal includes the force required to overcome the inertia of the screw moving the edge ring from a rest position. The signal corresponding to the weight of the edge ring is minus the inertia within the electrical signal and any noise related to friction or inherent to the encoder or controller.

[0057] The method continues to operation 508, where a maintenance operation is performed on the edge ring in response to calculated metrics. The maintenance operation can be performed on the adjustable tuning ring. For example, during routine maintenance, the edge ring or adjustable tuning ring may be moved or replaced. The position of the replacement edge ring should be calibrated so that the replacement edge ring is substantially parallel to the substrate support surface. However, it is undesirable for some material to accumulate in the processing chamber, causing the adjustable tuning ring or other components to wedge into the substrate support assembly. Therefore, when the replacement edge ring is not in the correct position, the adjustable tuning ring can be readjusted so that the replacement edge ring is substantially parallel to the substrate support surface. In another example, the adjustable tuning ring is removed and cleaned. If the adjustable tuning ring conforms to specifications, the adjustable tuning ring is repositioned within the substrate support. In one example, the vertical height of the ring can be adjusted, for example, the vertical height of the edge ring or adjustable tuning ring relative to the substrate support surface. If the adjustable tuning ring no longer conforms to specifications, the adjustable tuning ring is replaced.

[0058] In another example, the maintenance performed in operation 508 is in response to the load or weight of a processing kit ring, such as an edge ring. As previously described, sensors are capable of detecting the weight of the edge ring. Thus, when the edge ring erodes, its weight decreases, and the controller detects the corresponding amount of erosion. The controller calculates the amount of erosion based on the weight of the edge ring. When the weight of the edge ring reaches a minimum threshold, the controller generates a signal or alarm to remind the operator that the edge ring should be replaced. Therefore, the edge ring is removed and a replacement edge ring is installed.

[0059] In operation 510, method 500 returns to operation 502 and method 500 continues. In one example, operation 502 continues when the edge ring or tuning ring is replaced. In another example, operation 502 is performed during routine maintenance. And, in yet another example, operations 502, 504, and 506 can proceed for a predetermined amount of time, or until the threshold erosion of the edge ring is determined.

[0060] The examples disclosed herein relate to methods and apparatus for determining the position of a ring within a processing suite. Advantageously, the disclosed methods and apparatus enable the determination of the ring's position when the ring is obscured from direct optical monitoring. Although the foregoing is directed to specific examples, other examples can be designed without departing from their basic scope, and the scope of which is determined by the appended claims. [Simplified Explanation of the Diagram]

[0011] In order to understand in detail the above-described features of the present invention, a more specific description of the present invention, which has been briefly summarized above, can be obtained by referring to examples, some of which are shown in the accompanying drawings. However, it should be noted that the drawings are merely exemplary examples and should not be considered as limiting its scope, and other equally effective examples are permissible.

[0012] Figure 1 is a schematic cross-sectional view of a processing chamber with a substrate support assembly.

[0013] Figure 2 shows an enlarged partial cross-sectional view of the processing kit disposed on the substrate support assembly in the processing chamber of Figure 1.

[0014] Figure 3 illustrates an alignment component configured to obtain a measurement of the ring of the processing kit, as shown in Figure 2.

[0015] Figure 4 is a cross-sectional view of the alignment component, which shows details of the alignment component housing.

[0016] Figure 5 is a flowchart of a method for measuring edge loop measurement using an alignment component, as shown in Figures 3-4.

[0017] For ease of understanding, the same element symbols are used where possible to represent common elements in the figures. It is anticipated that elements and features of one example can be beneficially incorporated into other examples without further description. [Biomaterial Storage]

[0062] Domestic storage information (please note in order of storage institution, date, and number): None. International storage information (please note in order of storage country, institution, date, and number): None.

Claims

1. A sensor assembly for a substrate processing chamber, comprising: A housing having a top surface, a bottom surface opposite the top surface, and a plurality of sidewalls connecting the top surface to the bottom surface, the housing further including a recess in the top surface forming an internal volume within the housing; a biasing member; a contact member disposed on the biasing member, wherein the biasing member and the contact member are disposed within the recess; and a sensor for detecting a displacement of the contact member corresponding to a relative position of an edge ring.

2. The sensor assembly according to claim 1, wherein the sensor is a light emission sensor having a light frequency from about 500 nm to about 1000 nm and a beam diameter from about 25 micrometers to about 75 micrometers.

3. The sensor assembly as claimed in claim 1, wherein the biasing member has a spring constant between about 2.5 psi and about 4.5 psi.

4. The sensor assembly as claimed in claim 1, wherein the sensor is a light emission sensor having a light frequency from about 600 nm to about 750 nm and a beam diameter from about 25 to about 75 micrometers, and wherein the biasing member has a spring constant of more than 2.75 psi.

5. The sensor assembly as described in claim 1, further comprising: A aligning pin having an upper end and a lower end, the upper end being configured to contact an adjustable tuning ring, and the lower end being configured to displace a bias member, wherein the edge ring contacts the adjustable tuning ring.

6. The sensor assembly as claimed in claim 5, wherein the contact member is disposed between the lower end of the alignment pin and the biasing member.

7. The sensor assembly as claimed in claim 1, wherein the edge ring further comprises: The first ring component; and a second ring component, wherein each of the first and second ring components forms a ring body.

8. The sensor assembly as claimed in claim 1, further comprising: A transparent window having a top surface and a bottom surface, the transparent window being mechanically coupled to the bottom surface of the housing, wherein the sensor is coupled to the bottom surface of the transparent window.

9. The sensor assembly as claimed in claim 1, further comprising: A plurality of exhaust channels extend through the top surface of the housing and into the recess.

10. The sensor assembly as claimed in claim 9, wherein the plurality of exhaust channels fluidly couple the recess to the same pressure as the substrate processing chamber.

11. An edge ring metric measurement system, comprising: An edge ring is disposed on a substrate support surface; A housing having a top surface, a bottom surface opposite the top surface, and a plurality of sidewalls connecting the top surface to the bottom surface, the housing further including a recess in the top surface forming an internal volume within the housing; a biasing member; a contact member disposed on the biasing member, wherein the biasing member and the contact member are disposed within the recess; an alignment pin mechanically contacting the edge ring and the contact member; and a light emission sensor for detecting a displacement of the contact member corresponding to a measurement of the edge ring.

12. The edge ring measurement system as claimed in claim 11, wherein the light emission sensor has an optical frequency from about 500 nm to about 1000 nm and a beam diameter from about 25 micrometers to about 75 micrometers.

13. The edge ring measurement system as claimed in claim 11, wherein the biasing member has a spring constant between approximately 2.5 psi and approximately 4.5 psi.

14. The edge ring measurement system as claimed in claim 11, wherein the light emission sensor has an optical frequency from about 600 nm to about 750 nm and a beam diameter from about 25 micrometers to about 75 micrometers, and wherein the biasing member has a spring constant of more than 2.75 psi.

15. The edge ring measurement system as described in claim 11, wherein, The alignment pin further includes: an upper end configured to contact an adjustable tuning ring, and a lower end configured to displace the bias member, wherein the contact member is disposed between the lower end of the alignment pin and the bias member, and wherein the edge ring contacts the adjustable tuning ring.

16. The edge ring measurement system as described in claim 11, further comprising: A plurality of exhaust channels extend through the top surface of the housing and into the recess.

17. A semiconductor processing system, comprising: A processing chamber configured to process a substrate; A housing having a top surface and a recess in the top surface, the recess forming an internal volume within the housing; a biasing member; a contact member disposed on the biasing member, wherein the biasing member and the contact member are disposed within the recess; a sensor configured to detect a displacement of the contact member corresponding to a relative position of an edge ring; and a non-transitory computer-readable medium storing instructions that, when executed by a processor, cause a method to be performed in a processing chamber, the method comprising the steps of: receiving a signal at the sensor emanating below a substrate support surface configured to have the edge ring disposed thereon, the edge ring being configured to surround the substrate; and detecting a displacement of the edge ring. Calculate a metric for the edge ring based on the displacement; and respond to the metric to perform a maintenance operation on the edge ring.

18. The semiconductor processing system of claim 17, wherein the metric is a weight of the edge ring.

19. The semiconductor processing system of claim 18, wherein the maintenance operation includes: Adjust the vertical height of the edge ring.

20. The semiconductor processing system as claimed in claim 18, wherein the metric corresponds to a quantity of edge ring erosion.

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