Rapid chamber vacuum leak detection hardware and maintenance procedures

Abstract

Methods and apparatus for detecting vacuum leaks within a process chamber are described herein. More specifically, the methods and apparatus relate to utilizing a spectroscopic measurement device, such as a spectrometer, to determine a leak rate within a process chamber while the process chamber is maintained at a leak test pressure. The spectroscopic measurement device determines the rate of increase of one or more gases within the process chamber and can be used to determine whether the process chamber passes or fails a leak test.

Description

background Technical Field

[0002] The embodiments of this disclosure generally relate to apparatus and methods for semiconductor processing. More specifically, the disclosed methods and apparatus relate to leakage detection within a semiconductor processing chamber.

[0003] Description of the prior art

[0004] Semiconductor substrates are processed for a wide range of applications, including the fabrication of integrated devices and microdevices. During processing, the substrate is placed on a pedestal or substrate support within a processing chamber. Extremely precise process conditions and gas flow rates are used to process the semiconductors. This is especially true in epitaxial deposition processes and rapid thermal processing. A vacuum seal within the processing chamber is crucial to prevent leakage of external air or process gases into the chamber during operation. If the vacuum components or seal are compromised between processes, a large number of substrates may pass through the chamber and become contaminated before a leak is detected.

[0005] Traditional leak testing requires cooling the chamber and running a standard pressure rise rate test to detect any leaks caused by component failure. This process includes cooling the chamber, stabilizing the temperature and pressure within the chamber, acquiring the rise rate data after evacuation and isolation, reheating the chamber, and recalibrating the chamber for semiconductor processing. This process requires significant time to cool the processing chamber and reheat it to processing temperature. Once reheated, the processing chamber must be recalibrated and conditioned before it can be used to process the substrate again. Cooling, reheating, and recalibration result in substantial downtime and lost production. Alternative methods include using helium leak measurement tools to measure the amount of helium within the chamber. While these systems can sometimes measure small leaks, traditional processes require significant system downtime, reducing the time the chamber is available for semiconductor processing.

[0006] Therefore, there is a need for an improved method and equipment for rapidly detecting small vacuum or seal leaks caused by component wear or failure, while maintaining the chamber at the processing temperature. Summary of the Invention

[0007] This disclosure generally relates to methods and apparatus for detecting vacuum leaks in a semiconductor processing chamber. In one embodiment, a method for detecting vacuum leaks is described herein. The method includes evacuating the processing chamber from a first pressure to a second pressure, wherein the second pressure is less than the first pressure. The method further includes activating a spectrometer and closing a chamber isolation valve after evacuating the chamber to the second pressure. During a sampling time, spectral data is collected from a conduit using the spectrometer. The chamber leakage rate is calculated based on the spectral data.

[0008] In another embodiment, the method of processing a substrate includes performing a leak detection test. The leak detection test includes evacuating a processing chamber to a leak test pressure, activating a spectrometer, closing a chamber isolation valve after evacuating the processing chamber to a second pressure, collecting spectral data from a conduit using the spectrometer during a sampling time, and calculating a chamber leakage rate based on the spectral data. After the leak detection test, the processing chamber leaks from the leak test pressure to a processing pressure greater than the leak test pressure after collecting the spectral data, and after evacuating the processing chamber to the processing pressure, substrate processing operations are performed on multiple substrates. After performing substrate processing operations on the multiple substrates, the leak detection test is repeated.

[0009] In another embodiment, a processing chamber for processing a substrate is described. The processing chamber includes a chamber body defining a processing volume, a processing gas inlet, and a processing gas outlet. The processing gas outlet includes a first conduit fluidly coupled between the processing volume and an exhaust pump, a chamber isolation valve disposed between the processing volume and the exhaust pump, and a spectrometer fluidly coupled to the first conduit between the processing volume and the chamber isolation valve. A controller is coupled to the processing chamber. The controller is configured to evacuate the processing chamber to a leak test pressure, activate the spectrometer, close the chamber isolation valve after evacuating the chamber to the leak test pressure, collect spectral data from the first conduit using the spectrometer during a sampling time, and calculate the chamber leakage rate based on the spectral data. Attached Figure Description

[0010] To gain a more detailed understanding of the features described above, reference can be made to embodiments of the present disclosure, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only exemplary embodiments and should not be considered as limiting the scope of the present disclosure, and other equally effective embodiments are permissible.

[0011] Figure 1 This is a schematic cross-sectional view of a substrate processing system according to one embodiment.

[0012] Figure 2A This is a schematic cross-sectional view of a processing chamber according to one embodiment.

[0013] Figure 2B This is a schematic cross-sectional view of a processing chamber according to another embodiment.

[0014] Figure 3 Measurement based on one implementation method Figure 2A or Figure 2B A method for dealing with leakage rate within a chamber.

[0015] Figure 4 This is a method for calibrating a leak detection system according to one embodiment.

[0016] Figure 5 This is a graph illustrating the measured purity of samples processed in the chamber in several experiments.

[0017] Figure 6 It is a graph illustrating the initial and final pressures measured in the treatment chamber during several tests.

[0018] For ease of understanding, the same element symbols are used as much as possible to represent the same elements in the drawings. It is conceivable that elements and features of one embodiment may be beneficially incorporated into other embodiments without further description. Detailed Implementation

[0019] This disclosure generally relates to apparatus and methods for semiconductor processing. More specifically, it relates to the detection of vacuum leaks within a heat treatment chamber. The apparatus for detecting vacuum leaks includes a photoemission spectrometer of the processing chamber vacuum system attached above a chamber isolation valve. The photoemission spectrometer measures the concentrations of different gases within the exhaust line and determines the leakage rate. In some embodiments, the photoemission spectrometer measures leakage of N2 and / or O2 into the processing chamber.

[0020] By utilizing the optical emission spectrometer and method described herein, chamber leaks can be detected at a leak rate of less than 0.5 mTorr / min. At the same temperature as the processing chamber, leaks can be detected in less than three minutes every few hours. Therefore, there is no need to lower the processing chamber temperature, and small leaks can be detected within a short timeframe without manual intervention or significant downtime for processing the chamber. Previous methods that run leak tests every four hours result in a decrease in tool availability of approximately 3%. The embodiments of this disclosure reduce the decrease in tool availability to only 0.5%.

[0021] Figure 1 This is a schematic cross-sectional view of a substrate processing system 100 according to one embodiment. System 100 is a cluster tool including a first chamber 102, a second chamber 104, a third chamber 106, a fourth chamber 108, a fifth chamber 110, and a central transfer chamber 112, which defines a transfer space 118 containing a central transfer robot 116. System 100 further includes a controller 120 coupled to system 100. Controller 120 is programmed to execute a plurality of instructions for the operation of system 100 to manufacture semiconductor devices, including the operation of the central transfer robot 116 and the operation of chambers 102-110 and loading chamber 114. Figure 2AAs shown, controller 120 includes a programmable central processing unit (CPU) operating with memory 255 and a large storage device, an input control unit, and a display unit (not shown). Controller 120 includes hardware for monitoring substrate processing via sensors in the processing chambers, and for monitoring precursor, processing gas, and purge gas flows. Support circuitry 258 is coupled to the CPU 252 for conventionally supporting the processor. Chambers 102-110 are each disposed around and coupled to a central transfer chamber 112. A central transfer robot 116 is configured to transfer substrates between loading chamber 114 and one or more chambers 102-110 via transfer space 118.

[0022] Although not in Figure 1 As shown, however, chambers 102, 104, 106, 108, and / or 110 of system 100 may further include one or more remote plasma sources and one or more gas sources for precursor gas, carrier gas, and other process gases. System 100 may also include multiple components, such as sensors and controllers, the controllers being configured to control the pressure, temperature, gas flow, and gas composition in some or all of the chambers 102-110. System 100 can thus be configured to form a desired structure and apparatus. Each of chambers 102, 104, 106, 108, and / or 110 may be one of a variety of different types of semiconductor processing chambers. Exemplary chambers include epitaxial deposition chambers, rapid thermal processing (RTP) chambers, etching chambers, thermochemical vapor deposition (CVD) chambers, plasma-enhanced chemical vapor deposition (PECVD) chambers, or cleaning chambers.

[0023] Figure 2A This is a schematic cross-sectional view of a deposition chamber 200a according to one embodiment. The deposition chamber 200a may be... Figure 1 Any of chambers 102-110. The deposition chamber 200a described herein is an epitaxial deposition chamber or a thermal deposition chamber. The deposition chamber 200a is generally used to grow an epitaxial film on a substrate such as substrate 202. The deposition chamber 200a generates a crossflow of precursors across the entire top surface 250 of substrate 202.

[0024] The deposition chamber 200a includes an upper body 256, a lower body 248 disposed below the upper body 256, and a flow module 212 disposed between the upper body 256 and the lower body 248. The upper body 256, the flow module 212, and the lower body 248 form the chamber body. Within the chamber body are a base 206, an upper dome 208, a lower dome 210, a plurality of upper lamps 241, and a plurality of lower lamps 243. A controller 120 is coupled to the chamber 200a and can be used to control all chamber processes described herein. The base 206 is disposed between the upper dome 208 and the lower dome 210. The plurality of upper lamps 241 are disposed between the upper dome 208 and a cover 254. The cover 254 includes a plurality of sensors (not shown) disposed therein for measuring the temperature within the deposition chamber 200a. The plurality of lower lamps 243 are disposed between the lower dome 210 and the ground 201. The plurality of lower lamps 243 form a lower lamp assembly 245.

[0025] A processing volume 236 is formed between the upper dome 208 and the lower dome 210. A base 206 is disposed in the processing volume 236. The base 206 includes a top surface on which a substrate 202 is disposed. The base 206 is attached to a shaft 218. The shaft is connected to a motion assembly 220. The motion assembly 220 includes one or more actuators 230 and / or adjustment devices, each of which provides movement and / or adjustment of the shaft 218 and / or the base 206 within the processing volume 236.

[0026] The base 206 may include a lifting rod hole 207 disposed therein. The lifting rod hole 207 is sized to accommodate a lifting rod 232 for lifting the substrate 202 from the base 206 before or after performing a deposition process. When the base 206 descends from the processing position to the transfer position, the lifting rod 232 may rest on a lifting rod stop 234.

[0027] The flow module 212 includes multiple process gas inlets 214, multiple purge gas inlets 264, and one or more exhaust outlets 216. The multiple process gas inlets 214 and multiple purge gas inlets 264 are disposed on one side of the flow module 212 opposite to the one or more exhaust outlets 216. A gasket 263 is disposed on the inner surface of the flow module 212 and protects the flow module 212 from the reactive gases used during the deposition process. The process gas inlets 214 and purge gas inlets 264 are positioned such that the gases flow parallel to the top surface 250 of the substrate 202 disposed within the processing volume 236.

[0028] Processing gas inlet 214 is fluidly connected to processing gas source 251 via processing gas conduit 253. Purified gas inlet 264 is fluidly connected to purified gas source 262 via purified gas conduit 260. One or more exhaust outlets 216 are fluidly connected to exhaust pump 257 via exhaust conduit 278.

[0029] A reference leak device 295 is fluidly coupled to a process gas conduit 253 via a reference leak conduit 256. A reference leak isolation valve 259 is disposed along the reference leak conduit 256 and located between the reference leak isolation valve 259 and the process gas conduit 253. During leak detection calibration, the reference leak device 295 may discharge a small amount of leaked gas into the process gas conduit 253 through the reference leak conduit 256 before the leaked gas enters the process volume 236. The small amount of leak that can be discharged by the reference leak device 295 may be from about 0.005 sccm to about 3 sccm, such as from about 0.01 sccm to about 2 sccm, such as from about 0.02 sccm to about 1 sccm. In some embodiments, the amount of leaked gas is less than about 0.03 sccm, such as less than about 0.025 sccm. In some embodiments, the reference leak device 295 is a small gas panel. The reference leak isolation valve 259 may be opened to allow leaked gas to escape through the reference leak conduit 256. The reference leak isolation valve 259 is closed in another manner, sealing and isolating the reference leak device 295 in the treatment volume 236. In some embodiments, the reference leak isolation valve 259 is used to protect the reference leak device 295 during the flow of treatment gas through the treatment gas inlet 214.

[0030] A chamber isolation valve 271 is disposed along an exhaust conduit 278 between the exhaust outlet 216 and the exhaust pump 257. The chamber isolation valve 271 is capable of opening or closing to form a seal between the exhaust outlet 216 and the exhaust pump 257, such that when the chamber isolation valve 271 is closed, no gas escapes from the processing volume 236 through the exhaust conduit 278. A spectrometer 292 and a vacuum gauge 293 are fluidly connected to the exhaust conduit 278 between the exhaust outlet 216 and the chamber isolation valve 271.

[0031] A throttle valve 272 is additionally provided between the chamber isolation valve 271 and the exhaust pump 257. The throttle valve 272 is configured to control the gas flow rate through the exhaust conduit 278 during substrate processing. In some embodiments, the throttle valve 272 and the chamber isolation valve 271 may be the same. However, it is sometimes difficult to control the process gas flow through the exhaust conduit 278 using only one of the throttle valve 272 or the chamber isolation valve 271. For example, the throttle valve 272 may not form a complete seal between the process volume 236 and the exhaust pump 257. Although the isolation valve 271 is generally able to form a seal between the process volume 236 and the exhaust pump 257, the isolation valve 271 may be less efficient in precisely controlling the process gas flow rate during substrate processing. However, in some embodiments, a valve capable of forming a sufficient seal can be used while performing leak calibration and precisely controlling the gas flow rate through the exhaust conduit 278 during substrate processing.

[0032] A spectrometer 292 is fluidly or optically coupled to an exhaust duct 278. The spectrometer 292 is a spectrometer used to measure the gas composition within the exhaust duct 278. The spectrometer 292 can be fluidly coupled to the exhaust duct 278 via a first instrument conduit 269. The first instrument conduit 269 may have a first valve 267 disposed on the first instrument conduit 269, such that the first valve 267 is fluidly disposed between the spectrometer 292 and the connection between the first instrument conduit 269 and the exhaust duct 278. The first valve 267 is configured to close during substrate processing within the processing volume 236. Closing the first valve 267 prevents process gas from flowing to the spectrometer 292, as the spectrometer 292 may be sensitive to exposure to process gas. During vacuum leak checks within the deposition chamber 200a, the first valve 257 opens. Gas from the exhaust duct 278 flows into the spectrometer 292, and the spectrometer 292 determines the concentration of one or more gases within the exhaust duct 278.

[0033] In some embodiments, the spectrometer 292 is an optical emission spectrometer, such as a remote plasma optical emission spectrometer. The spectrometer 292 is used to measure light emission in the range of 250 nm to approximately 1000 nm, such as approximately 300 nm to approximately 900 nm, or approximately 300 nm to approximately 880 nm. In some embodiments, the light emission range of a gas sample is measured in an in-situ plasma cavity. In other embodiments, the spectrometer 292 may be optically coupled to an exhaust duct 278 and measure the gas concentration within the exhaust duct 278 through a window (not shown) provided through the side of the exhaust duct 278. The window may be accompanied by one or more reflectors disposed around the inner surface of a portion of the exhaust duct 278.

[0034] Vacuum gauge 293 is fluidly coupled to exhaust duct 278. Vacuum gauge 293 is configured to measure the pressure within exhaust duct 278. Vacuum gauge 293 helps determine the presence of any significant leaks within the system and is also used during the calibration of spectrometer 292. Vacuum gauge 293 may be a pressure gauge and may have an accuracy of less than 0.01 Torr, such as less than 5 mTorr or less than 1 mTorr. In some embodiments, vacuum gauge 293 is fluidly coupled to exhaust duct 278 via a second vacuum gauge conduit 299. One end of the second measuring instrument conduit 299 is coupled to exhaust duct 278, and the opposite end is coupled to vacuum gauge 293. A second valve 266 is disposed on the second measuring instrument conduit 299. The second valve 266 is disposed along the second measuring instrument conduit 299 between exhaust duct 278 and vacuum gauge 293. The second valve 266 is similar to the first valve 267 because the second valve 266 can be closed during substrate processing and opened during vacuum leak checks as described herein. When closed, the second valve 266 can shut off the vacuum gauge 293 and isolate it from the exhaust duct 278, so that the process gas does not reach the vacuum gauge 293.

[0035] The exhaust pump 257 can be any suitable gas pump used within the substrate processing chamber. The exhaust pump 257 can be part of an exhaust assembly (not shown). In some embodiments, the exhaust pump 257 is used with multiple processing chambers and its intensity is adjusted depending on the desired pressure and vacuum within the processing chambers.

[0036] Figure 2B This is a schematic cross-sectional view of a deposition chamber 200b according to another embodiment. The deposition chamber 200b may be... Figure 1 Any of chambers 102-110. Deposition chamber 200b is a rapid thermal processing (RTP) chamber. Exemplary RTP chambers may include those available from Applied Materials, Inc., Santa Clara, California. Alternatively, a RADIANCEPlus chamber may be used; however, chambers from other manufacturers may also be considered. The deposition chamber 200b is generally used to deposit films on a substrate (such as substrate 202) to form a semiconductor device. The deposition chamber 200b deposits precursors onto the top surface 250 of substrate 202.

[0037] The deposition chamber 200a includes an upper heating assembly 275, a main body 274, a substrate 285, a base 281, a first window 284, multiple pyrometers 289, multiple light guides 286, a processing gas source 251, an exhaust pump 257, and a purified gas source 262.

[0038] An upper heating assembly 275 is disposed on top of the body 274 of the deposition chamber 200a. The body 274 may be one or more components surrounding the substrate 285 and supporting the upper heating assembly 275. The body 274 may include a process gas inlet 215, a purge gas inlet 217, and an exhaust outlet 279. A first window 284 having a plurality of holes 278 formed through it is disposed within the upper portion of the body 274, such that the first window 284 rests on the top of a portion of the body 274. The first window 284 further serves as a radiation window for radiation emitted by the upper heating assembly 275. In some embodiments, the first window 284 is a quartz window.

[0039] An upper heating assembly 275 is disposed above a first window 284 and separated from the first window 284 by a second window 276. The second window 276 and the first window 284 form a distribution air chamber above the processing volume 280. The upper heating assembly 275 is coupled to an upper plate 276 and includes a plurality of lamps 277 for rapidly heating the processing space 280 and the top surface of the substrate 250. The lamps 277 are surrounded by one or more cooling channels. The lamps within the upper heating assembly 275 can be controlled by a controller such as controller 120. Radiation from the upper heating assembly 275 passes through the first window 284 and the second window 276 into the processing space 280. Alternatively (not shown), the upper heating assembly 275 is a lower heating assembly and is configured to heat the back side of the substrate 202, for example, by disposing the upper heating assembly 275 below the substrate 202 and guiding radiation to the back side of the substrate 202.

[0040] A substrate 285 is disposed within the main body 274 and below the base 281. The substrate 285 serves to support the base 281. The substrate 285 may be a water-cooled substrate and has a reflector 283 mounted on its top surface to reflect radiation, such that the reflector 283 reflects radiation from the upper heating assembly 275 to the back of the base 281 and the substrate 202. The base 281 is configured to support the substrate 202 and is disposed on top of the substrate 285 and below the first window 284.

[0041] The temperature of a localized area of ​​substrate 202 is measured by pyrometer 289. Pyrometer 289 is configured to measure the temperature of substrate 202 by measuring radiation emitted by substrate 202. Radiation from substrate 202 is emitted into light guides 286 disposed through substrate 285. Light guides 286 are positioned to receive radiation from different radial locations along substrate 202. The upper portion 282 of each light guide 286 is positioned adjacent to the underside of substrate 202 and base 281, while the lower portion 287 of each light guide 286 is attached to flexible optical fiber 288. Flexible optical fiber 288 is disposed between light guide 286 and pyrometer 289, and optically couples the lower end of light guide 286 to pyrometer 289, such that light guides 286 and flexible optical fiber 288 transmit radiation emitted by substrate 202 and / or base 281 to pyrometer 289. Each light guide 286 is located within the substrate 285 such that the upper portion 282 of the light guide is flush with or slightly below the upper surface of the substrate 285, such as slightly below or flush with the upper surface of the reflector 283. In some embodiments, the light guide 286 is directly connected to the pyrometer 289 without using the flexible optical fiber 288.

[0042] A pyrometer 289 is connected to a controller 120, which controls the power supplied to the upper heating assembly 275 in response to the measured substrate temperature. In some embodiments, such as for a 200 mm substrate, the upper heating assembly 275 uses multiple lamps, such as 187 lamps 277, to deliver highly collimated radiation from tungsten halogen lamps to the processing space 280. In some embodiments, such as for a 300 mm substrate, the upper heating assembly 275 may use multiple lamps, such as 409 lamps 277. The number and configuration of lamps disclosed herein are exemplary, and other numbers and configurations of lamps may be used.

[0043] Similar to Figure 2A The processing gas inlet 214 and processing gas inlet 215 of the deposition chamber 200a are fluidly connected to the processing gas source 251 via the processing gas conduit 253. The purified gas inlet 217 is fluidly connected to the purified gas source 262 via the purified gas conduit 260. The exhaust outlet 279 is fluidly connected to the exhaust pump 257 via the exhaust conduit 278.

[0044] For reference Figure 2A The reference leak device 295 is fluidly coupled to the processing gas conduit 253 via the reference leak conduit 256, and the reference leak isolation valve 259 is disposed between the reference leak isolation valve 259 and the processing gas conduit 253 along the reference leak conduit 256.

[0045] For reference Figure 2A The chamber isolation valve 271 is disposed along the exhaust conduit 278 between the exhaust outlet 279 and the exhaust pump 257. A spectrometer 292 and a vacuum gauge 293 are fluidly connected to the exhaust conduit 278 between the exhaust outlet 279 and the chamber isolation valve 271. A throttle valve 272 is additionally disposed between the chamber isolation valve 271 and the exhaust pump 257.

[0046] The exhaust pump 257 can be any suitable gas pump used within the substrate processing chamber. The exhaust pump 257 can be part of an exhaust assembly (not shown). In some embodiments, the exhaust pump 257 is used with multiple processing chambers and is adjustable in intensity depending on the desired pressure and vacuum within the processing chambers.

[0047] The controller 120 can control any one of the following: pyrometer 289, upper heating assembly 275, processing gas source 251, reference leakage device 295, exhaust pump 257, spectrometer 292, vacuum gauge 293, and any one of valves 259, 267, 268, 271, and 272.

[0048] Figure 3 Measurement based on one implementation method Figure 2A or Figure 2BA method 300 for treating leakage rate in a chamber. Method 300 includes a first operation 302, a second operation 304, a third operation 306, a fourth operation 308, a fifth operation 310, a sixth operation 312, a seventh operation 314, an eighth operation 316, a ninth operation 318 and a tenth operation 320 as described herein.

[0049] The first operation 302 is a calibration operation. The first operation 302 is performed after installation or maintenance is carried out on the processing system or cluster tools. The first operation 302 is used to calibrate the spectrometer 292 and / or the vacuum gauge 293. The first operation 302 may include references. Figure 4 All operations described herein, or other alternative calibration methods. In some embodiments, the spectrometer 292 and / or vacuum gauge 293 are calibrated at additional or alternative points throughout method 300. This document refers to... Figure 4 The first operation 302 will be described in further detail.

[0050] The second operation 304 includes reducing the processing chamber from a first pressure pump to a second pressure, which is less than the first pressure. The first pressure may be the pressure of the processing chamber (such as one of deposition chambers 200a and 200b) after it has been pressurized during the final portion of the deposition operation or after a calibration process. In some operations, if the calibration chamber is not restored to the substrate processing pressure, the first and second pressures may be equal. During the second operation 304, no gas flows into the chamber from a process gas or purge gas source. During or before the second operation 304, gas flow into the chamber from the process gas and / or purge gas source ceases. The second pressure is the pressure at which the minimum amount of gas leaks from each conduit (such as conduits 253, 256, 260, 266, 278, or 299) into the processing volume (such as processing volumes 236 and 280). The second pressure may also be referred to as the test pressure or leak test pressure.

[0051] When the pressure inside the processing chamber decreases, gas from the conduits flows back into the chamber and is degassed from gas deposits within the chamber. This makes detecting leaks into the processing chamber more difficult. Therefore, the pressure inside the chamber should be low enough to remove gas and create a vacuum, but also high enough to minimize any backflow effect. The second pressure can be determined during the second operation 304 by monitoring emissions from one or more of conduits 253, 256, 260, 266, 278, or 299 during the evacuation cycle, such that the emission intensity is below an acceptable threshold at the second pressure. Alternatively, the second pressure can be predetermined during the first operation 302. In some embodiments, the first pressure is from about 20 Torr to about 200 Torr, such as from about 50 Torr to about 150 Torr, such as from about 60 Torr to about 100 Torr, such as from about 70 Torr to about 90 Torr, such as about 80 Torr. In some embodiments, the second pressure is less than about 500 mTorr, such as about 20 mTorr to about 300 mTorr, such as about 30 mTorr to about 250 mTorr, such as about 50 mTorr to about 200 mTorr, such as about 75 mTorr to about 150 mTorr, such as about 80 mTorr to about 120 mTorr, such as about 100 mTorr.

[0052] During this operation, the processing chamber can be maintained at the substrate processing temperature. Maintaining the processing chamber at the substrate processing temperature during the leakage rate measurement method 300 reduces downtime and thus increases chamber availability. The substrate processing temperature can be from about 100°C to about 800°C, such as from about 100°C to about 750°C, such as from about 200°C to about 750°C. In embodiments using an epitaxial deposition chamber, such as... Figure 2A The deposition chamber 200a has a substrate processing temperature of approximately 250°C to approximately 800°C, such as approximately 300°C to approximately 750°C. In embodiments using an RTP chamber, such as... Figure 2B In the deposition chamber 200b, the substrate processing temperature is from about 150°C to about 450°C, such as from about 200°C to about 400°C. In the hot plate heater system, the substrate processing temperature is from about 100°C to about 700°C, such as from about 100°C to about 650°C.

[0053] The third operation 306 includes activating a spectrometer, such as spectrometer 292. Activating spectrometer 292 may include turning on spectrometer 292 or initiating sampling with spectrometer 292. In some embodiments, spectrometer 292 operates continuously in the background, but during the third operation 306, it begins collecting and / or saving spectral sampling data. The spectral sampling data may be stored in a controller, such as controller 120. When the spectrometer is activated, a valve, such as first valve 267, between the exhaust duct and the spectrometer is opened to allow gas to flow from the exhaust duct to the spectrometer.

[0054] The fourth operation 308 includes closing a chamber isolation valve, such as chamber isolation valve 271. The chamber isolation valve closes to seal the processing volume, such as processing volumes 236 and 280. While the chamber isolation valve is closed, the spectrometer measures the concentration of different gases within the exhaust duct and extends within the processing volume, causing the third operation 306 and the fourth operation 308 to overlap or occur simultaneously. This occurs within a settling time, while the chamber isolation valve closes to form a seal. The settling time can range from about 1 second to about 20 seconds, such as about 1 second to about 15 seconds, or about 2 seconds to about 10 seconds. After the settling time, the chamber isolation valve should be closed, isolating the processing volume from the exhaust pump. In some embodiments, after isolation valve 271 closes, a valve between the spectrometer and the exhaust duct opens.

[0055] The fifth operation 310 includes sampling spectral data from within an exhaust duct (such as exhaust duct 278) using a spectrometer. The spectral data is obtained using optical emission spectroscopy (OES). OES spectral data is collected during the fifth operation to determine the concentration of one or more gases within the exhaust duct. Sampling of the spectral data can be performed by obtaining multiple gas samples from the exhaust duct. This may include allowing a small, fixed amount of gas present in the exhaust duct to flow into a sample volume within the spectrometer, such as the in-situ plasma chamber of the spectrometer. The gas within the sample volume is then optically analyzed to determine the concentration of one or more gases within the sample volume. In the operation described herein, the concentration of one or more of N2, N, O, O2, H, or Ar is measured. The fifth operation 310 and the second, third, fourth, and sixth operations 304, 306, 308, and 312 can be performed at a temperature similar to the temperature at which the substrate is processed during the tenth operation 320. In some embodiments, the temperature during the fifth operation 310 is greater than about 250°C, such as greater than about 400°C, such as greater than about 500°C, such as greater than about 750°C.

[0056] Multiple samples of gas are collected from the exhaust duct. In some embodiments, the gas in the exhaust duct is measured at a rate of approximately 20 samples / minute to approximately 150 samples / minute, such as approximately 30 samples / minute to approximately 120 samples / minute, such as approximately 45 samples / minute to approximately 100 samples / minute, such as approximately 60 samples / minute. Samples can be collected for a total duration of approximately 15 seconds to approximately 100 seconds, such as approximately 20 seconds to approximately 90 seconds, such as approximately 30 seconds to approximately 75 seconds, such as approximately 30 seconds to approximately 50 seconds, such as approximately 32 seconds. Therefore, approximately 5 samples to approximately 180 samples can be collected, such as approximately 20 samples to approximately 180 samples, such as approximately 30 samples to approximately 120 samples.

[0057] Increasing the number and frequency of samples improves the resolution of data and trend analysis, thereby revealing leaks within the processing chamber. Sampling typically takes less than two minutes, minimizing downtime in the processing chamber during leak detection. When using OES to collect samples, the elemental composition of the gas within the exhaust duct can be determined, and the concentrations of one or more gases can be identified, regardless of the processing gas used.

[0058] The sixth operation 312 is performed after the fifth operation 310 and includes calculating the intensity of the increase in gas concentration within one or more samples of spectral data. The intensity of the increase in gas concentration in the sample is determined by measuring the rate of increase in one or more gas concentrations associated with air leakage. In the embodiments described herein, the measured gases include N2, N, O, O2, and Ar. The intensity of the increase in gas concentration is calculated in controller 120. The acceptable rate of atmospheric leakage into the processing chamber from the external environment, another chamber, an exhaust system component, or a gas panel component is determined by the user. The acceptable leakage rate determines the acceptable rate of increase in one or more gas concentrations. In some operations, the sixth operation 312 may be performed simultaneously with the collection of spectral data during the fifth operation 310. In other embodiments, all spectral data is collected, and then the purity within the processing chamber is calculated.

[0059] The seventh operation 314 includes deactivating the spectrometer and opening the chamber isolation valve. After spectral data samples have been acquired during the fifth operation 310, the valve between the spectrometer and the exhaust duct can be closed, and the spectrometer deactivated. The chamber isolation valve can be reopened simultaneously or immediately thereafter to unblock the processing chamber. The valve between the spectrometer and the exhaust duct can be closed to protect the spectrometer from the processing gases during substrate processing. The seventh operation 314 can be performed, as appropriate, before, after, or after the sixth operation 312, such that the intensity of the increase in gas concentration in the processing chamber is calculated when the spectrometer is deactivated and the chamber isolation valve is opened, or after the spectrometer is deactivated and the chamber isolation valve is opened.

[0060] The eighth operation 316 includes comparing the intensity of the increase in gas concentration in the sample with a calibrated intensity of the increase in gas concentration measured during the first operation 302 to determine the leakage rate and decide whether the processing chamber passes or fails the leakage test. The calibrated intensity of the increase in gas concentration may be the rate at which the processing chamber will fail the leakage test, such that once the intensity value exceeds the calibrated intensity, the processing chamber will have a leakage exceeding a predetermined maximum leakage value. (Reference) Figure 4 The method for determining calibration purity is described in more detail. In some embodiments, the eighth operation 316 is performed before the spectrometer is deactivated and the chamber isolation valve is opened. Alternatively, the eighth operation may be performed after the sixth operation 312.

[0061] In some embodiments, if a leak exceeding a predetermined limit is determined in the processing chamber during the eighth operation 316, additional processing operations may be performed. During the additional operation, a reference leak device, such as reference leak device 295, is activated by opening a valve between a reference leak device and a processing gas conduit (such as processing gas conduit 253), and the reference leak device releases a predetermined amount of leaked gas. In some embodiments, the predetermined amount of leaked gas is about 0.005 sccm to about 3 sccm, such as about 0.01 sccm to about 2 sccm, such as about 0.02 sccm to about 1 sccm. In some embodiments, the predetermined amount of leaked gas is less than about 0.03 sccm, such as less than about 0.025 sccm. A spectrometer can then measure the gas concentration in the exhaust conduit in a manner similar to that described with respect to the fifth operation 510. As a predictable amount of known gas is released into the processing chamber, the controller can then determine whether the purity calculation determined based on the original leak is correct, or whether the system should be recalibrated and / or whether the leak test has been performed for an additional period of time. This additional operation can be performed in an embodiment where the eighth operation 316 precedes the seventh operation 314. Performing the additional operation before the seventh operation 314 ensures that the spectrometer remains active and the chamber isolation valve remains closed. This ensures measurement consistency between purity and leakage tests, while the reference leakage device actively provides a reference leakage.

[0062] The ninth operation 318 includes evacuating the processing chamber to a processing pressure. The processing pressure may be a third pressure, such that the third pressure is greater than the second pressure. In some embodiments, the third pressure is the same as the first pressure. In other embodiments, the first pressure and the third pressure are different. In the embodiments disclosed herein, the third pressure is about 20 to about 200 tors, such as about 50 to about 150 tors, such as about 60 to about 100 tors, such as about 70 to about 90 tors, such as about 80 tors. Increasing the pressure within the processing chamber can be achieved by allowing one or more gases to flow from a processing gas inlet or a purifying gas inlet.

[0063] The tenth operation 320 includes processing one or more substrates in a processing chamber, such as deposition chambers 200a and 200b. Processing the one or more substrates includes performing semiconductor formation operations, such as deposition operations, on the substrates. After one or more substrates have been processed during the tenth operation 320, the second to tenth operations 302-320 can be repeated or cycled. This cycle can be repeated within a predetermined time period, or after a set number of substrates have been processed in the processing chamber. After repeating the second to tenth operations 302-320, preventative maintenance can be performed again, and the entire process 300 can be restarted.

[0064] In some operations, a leak detection operation is performed before / after every n substrates, such that the leak detection operation is performed before / after processing n substrates in the processing chamber. In embodiments where leak testing is performed between processing a predetermined number of substrates, the leak test is performed after approximately 2 to approximately 2000 substrates have been processed in the processing chamber, such as approximately 25 to approximately 1000 substrates, or approximately 100 to approximately 750 substrates. In other embodiments, the leak detection operation is performed after a predetermined operation time, such as approximately 1 hour to approximately 24 hours, approximately 2 hours to approximately 12 hours, or approximately 3 hours to approximately 5 hours. In some embodiments, the system runs a leak detection operation at least once every 24 hours. In other embodiments, the leak detection operation is performed after system maintenance has been performed and / or the processing chamber has been idle for an extended period.

[0065] Figure 4 This is a detailed calibration operation 302 of a post-maintenance calibration leak detection system according to one embodiment. Operation 302 includes performing preventative maintenance on the processing chamber during a first operation 402, evacuating the processing chamber to a first pressure during a second operation 404, sampling spectral data and measuring the pressure in the processing chamber over time during a third operation 406, filling the calibration table during a fourth operation 408, and calculating the acceptable / unacceptable purity values ​​of the processing chamber during a fifth operation 410.

[0066] The first preventative maintenance operation 402 is performed at the start of calibration operation 302, depending on the circumstances. Preventative maintenance may include regular cleaning of the processing chamber, repair of internal components, replacement of internal components, or modification of the processing chamber. Preventative maintenance can be performed throughout the lifespan of the processing chamber.

[0067] After performing preventative maintenance on the processing chamber, the processing chamber generally undergoes several initial operating procedures to preheat it. This includes evacuating the processing chamber to processing pressure and running one or more test substrates through the processing chamber.

[0068] The second operation 404, evacuating the processing chamber to the first pressure, includes reducing the pressure within the processing chamber from the post-maintenance pressure or processing pressure to a pressure similar to the second pressure described above. In some embodiments, the pressure is reduced to approximately 20 mTorr to approximately 300 mTorr, such as approximately 30 mTorr to approximately 250 mTorr, such as approximately 50 mTorr to approximately 200 mTorr, such as approximately 75 mTorr to approximately 150 mTorr, such as approximately 80 mTorr to approximately 120 mTorr, such as approximately 100 mTorr. Evacuating the processing chamber to the calibration pressure may be performed in stages, such that the processing chamber is evacuated for a set duration before evacuation is stopped, and the chamber is isolated to perform the third operation 406, as described below. In some embodiments, the processing chamber is evacuated to the calibration pressure in less than 60 seconds, such as less than 30 seconds. In some embodiments, the step of evacuating the processing chamber to the calibration pressure is performed in approximately 0.1 seconds to approximately 60 seconds, such as approximately 3 seconds to 60 seconds, such as approximately 5 seconds to approximately 15 seconds.

[0069] Concurrently with the second operation 404, a third operation 406 can be performed to sample spectral data from the processing chamber and measure the pressure change over time. As described above, the sampling of the spectral data is performed by a spectrometer, such as spectrometer 292. This can be combined with... Figure 3 Method 300 performs spectral data sampling in a similar manner to measuring spectral data during the fifth operation 310. During the third operation 406, the evacuation of the processing chamber is temporarily stopped, and the chamber is isolated using the chamber isolation valve 271, thereby allowing the rate of gas rise within the chamber to be determined based on the pressure at which evacuation stops.

[0070] Using a pressure gauge, such as vacuum gauge 293, the pressure and its change over time are measured. When the processing chamber is evacuated to the calibration pressure, the pressure change over time can be calculated by performing periodic pressure measurements. A curve can be fitted to the measured pressure change values ​​to determine the pressure variation over time.

[0071] After obtaining spectral and pressure data during the third operation 406, the spectral data can be converted into intensity values ​​by calculating the rate of change of one or more gas concentrations in the processing chamber.

[0072] During the fourth operation 408, the calculated intensity and pressure values ​​are plotted relative to each other to form a calibration table. The calibration table can be determined for removal rates from approximately 0.2 mTorr / min to approximately 100 mTorr / min, such as from approximately 0.3 mTorr / min to approximately 75 mTorr / min, such as from approximately 0.4 mTorr / min to approximately 50 mTorr / min, and such as from approximately 0.5 mTorr / min to approximately 40 mTorr / min. The intensity values ​​can be arbitrary, determined by the rate of change of one or more gas concentrations within the processing chamber. Generally, a higher intensity value equals a larger rate of change of one or more gas concentrations within the processing chamber. The calibration table can also be used to determine... Figure 3The optimal pressure used during leak testing operations, such as regarding Figure 3 The second operation 304 of method 300 describes the second pressure.

[0073] The second operation 404, the third operation 406, and the fourth operation 408 can be cycled to fill a complete calibration table. As described above, the second operation 404 is performed to evacuate the processing chamber to a set pressure before the processing chamber is isolated, and the gas inside the processing chamber is sampled to obtain spectral data. The spectral data is accompanied by a standard rise rate of the gas inside the chamber to determine the leakage rate of the processing chamber at the set pressure. Cyclic operation of this method fills a complete calibration table at different pressures inside the processing chamber.

[0074] During the fifth operation 410, acceptable / unacceptable purity values ​​are determined. These values ​​are determined using a calibration table established during the fourth operation 408 and the maximum acceptable leakage value. The maximum acceptable leakage value can be entered by the user and is in some embodiments approximately 0.1 mTorr / min to approximately 1 mTorr / min, such as approximately 0.3 mTorr / min to approximately 0.7 mTorr / min, or approximately 0.5 mTorr / min. When entered into the calibration table, acceptable purity values ​​for passing or failing the leak test are determined by extrapolation or by matching the acceptable purity value to a previously measured leakage rate. The acceptable / unacceptable purity limits can be recalculated each time the chamber is subjected to preventative maintenance.

[0075] In some implementations, a calibration leak is used to determine the pass / fail threshold. In this implementation, during the second operation 404 and the third operation 406, after the processing chamber has shown to be leak-free, an intensity test is repeated using a spectrometer with the calibration leak open. The calibration leak is opened to release gas at a rate that meets the user's pass / fail criteria. Therefore, the intensity of the increase in gas concentration calculated during the use of the calibration leak becomes the pass / fail threshold.

[0076] Figure 5Figure 500 shows the measured purity of samples from the processing chamber in several tests. The measured purity was used using a method similar to that described above. On the graph, the purity value is represented by any contamination rate (i.e., the increase of one or more gas concentrations over time) on the y-axis. The left side of the graph, 502, shows the tests performed without leakage. The graph shows the measured contamination rate for non-leaking O2 506 and non-leaking N2 508. The right side of the graph, 504, shows the tests performed with leakage, such as a leak from reference leak device 295. The reference leak might be a leak of approximately 0.3 mTorr / min. The graph shows the measured contamination rate for leaking O2 510 and leaking N2 512. As shown in Figure 500, when comparing the test values ​​for non-leaking N2 508 with those for leaking N2 512, it can be seen that the N2 contamination rate entering the processing chamber is significantly higher. When the test value of non-leaking O2 506 was compared with the test value of leaking O2 510, the O2 contamination rate entering the treatment chamber was also significantly higher.

[0077] Figure 6 Figure 600 shows the measured pressures within the processing chamber during several tests. Figure 600 compares the pressure measurements at the beginning and end of the purity test, when a leak is present and when there is no leak in the processing chamber. On the left, 602, the initial pressure 606 without leak is determined using a pressure gauge (e.g., vacuum gauge 293) and compared to the final pressure 608 without leak. As shown, even without a leak, the pressure within the processing chamber varies slightly. On the right, 604, the initial pressure 610 with a leak is determined using a pressure gauge and compared to the final pressure 612 with a leak. The pressure change within the processing chamber is small, but even without a leak, the pressure change is roughly equivalent to the pressure change shown. Therefore, the ability of differential pressure within the processing chamber to detect small leaks, such as less than about 1 mTorr or less than about 0.5 mTorr, is limited. Figure 5 As shown, using spectral measurements and detecting the rate of increase in the concentration of certain gases to calculate purity values ​​makes it easier to detect leaks.

[0078] As described herein, determining the presence or severity of leaks within a processing chamber can be challenging when relying on pressure data. Therefore, methods such as those described herein offer improved approaches for detecting leaks or leak rates within processing chambers. Spectroscopic measurements of the processing chamber at low pressure provide accurate and precise leak rate values. Monitoring the chamber's leak rate helps determine if chamber components have failed and reduces the amount of substrate contaminated by the chamber. A maximum leak rate can be input by the user, allowing for subsequent automation of the system, and the system will alert the user if the leak rate exceeds the maximum input.

[0079] The methods described herein can be used in any number of processing chambers, but examples of epitaxial deposition chambers and RTP chambers are provided. The methods described herein are particularly suitable for epitaxial deposition chambers and RTP chambers because the deposition steps typically performed in said chambers are highly sensitive to contamination from external atmospheric leaks.

[0080] Despite the foregoing embodiments of this disclosure, other and further embodiments of this disclosure may be designed without departing from the basic scope of this disclosure, and the scope of this disclosure is defined by the appended claims.

Claims

1. A method for detecting vacuum leaks, comprising: The processing chamber is evacuated from a first pressure to a second pressure, wherein the second pressure is less than the first pressure; Activate the spectrometer; After evacuating the processing chamber to the second pressure, close the chamber isolation valve; During the sampling period, spectral data are collected from the conduit using the aforementioned spectrometer; and The chamber leakage rate was calculated using the spectral data. The chamber isolation valve is located in the exhaust duct of the processing chamber downstream of the spectrometer and isolates the processing chamber.

2. The method of claim 1, further comprising the following steps: After collecting the spectral data, the processing chamber is evacuated from the second pressure to a third pressure greater than the second pressure; and After the processing chamber is evacuated to the third pressure, the substrate processing operation is performed.

3. The method of claim 1, wherein the collection of the spectral data is performed for 15 to 100 seconds.

4. The method of claim 1, wherein the spectral data includes the concentrations of oxygen, nitrogen, or oxygen and nitrogen within the catheter.

5. The method of claim 1, wherein the chamber leakage rate is calculated by comparing the rate at which the gas concentration in the catheter increases over time with a predetermined calibrated rate at which the gas concentration increases over time.

6. The method of claim 1, wherein the second pressure is a predetermined pressure calculated during the calibration operation.

7. The method of claim 1, wherein the second pressure is the lowest pressure of the gas flow in the upstream pipeline.

8. A method for processing a substrate, comprising: Perform leak detection tests, including: Evacuate the processing chamber to the leak test pressure; Activate the spectrometer; After evacuating the processing chamber to the leakage test pressure, close the chamber isolation valve. During the sampling period, spectral data are collected from the conduit using the aforementioned spectrometer; and The chamber leakage rate was calculated using the spectral data. After collecting the spectral data, the processing chamber is evacuated from the leak test pressure to a processing pressure greater than the leak test pressure; and After evacuating the processing chamber to the processing pressure, substrate processing operations are performed on multiple substrates; and Repeat the leak detection test.

9. The method of claim 8, wherein the plurality of substrates comprises a plurality of substrates.

10. The method of claim 8, wherein the leak detection test is performed in less than 300 seconds.

11. The method of claim 8, wherein the leak detection test is performed at a temperature above 250°C.

12. The method of claim 8, wherein the leak test pressure is 20 mTorr to 300 mTorr.

13. The method of claim 8, wherein the spectrometer measures radiation at wavelengths from 250 nm to 1000 nm.

14. A processing chamber for processing a substrate, comprising: A chamber body that defines a processing volume; Treat the gas inlet; Processed gas outlet, the processed gas outlet comprising: A first conduit is fluid-coupled between the processing volume and the exhaust pump; A chamber isolation valve is disposed between the processing volume and the exhaust pump; and A spectrometer, fluidly coupled to the first conduit between the processing volume and the chamber isolation valve; and The controller is configured to: The processing chamber is evacuated to the leak test pressure; Activate the spectrometer; After evacuating the processing chamber to the leakage test pressure, the chamber isolation valve is closed. During the sampling period, spectral data are collected from the first conduit using the spectrometer; and The chamber leakage rate is calculated based on the spectral data.

15. The processing chamber of claim 14, wherein the processing chamber further comprises: A second conduit is fluidly coupled between the first conduit and the spectrometer. and A measuring instrument isolation valve is disposed along the second conduit between the first conduit and the spectrometer.

16. The processing chamber of claim 14, wherein the processing chamber further comprises: Processing the gas source; A processing gas conduit is disposed between the processing gas source and the processing gas inlet; and A reference leak device, the reference leak device being fluidly coupled to the process gas conduit between the process gas source and the process gas inlet.

17. The processing chamber of claim 16, wherein a reference leak isolation valve is disposed between the reference leak device and the processing gas conduit.

18. The processing chamber of claim 14, wherein the vacuum gauge is fluidly coupled to the first conduit between the chamber isolation valve and the processing volume.

19. The processing chamber of claim 14, wherein the spectrometer is a photoemission spectrometer.

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