In-situ Growth Rate Sensor Using Epitaxial Self-Heating Type Sensor Tube

Abstract

This specification describes a method and apparatus for determining the growth rate on a semiconductor substrate. The apparatus is an optical sensor such as an optical growth rate sensor. The optical sensor is positioned in the exhaust of the deposition chamber. The optical sensor self-heats using one or more internal heating elements such as resistive heating elements. The internal heating element is configured to heat the sensor coupon. A film is formed on the sensor coupon by the exhaust gas flowing through the exhaust, which correlates with the film growth on the substrate within the process region of the deposition chamber.

Description

Technical Field

[0001]

[0001] Embodiments of the present disclosure generally relate to apparatuses and methods for manufacturing semiconductor devices. More specifically, the apparatuses disclosed herein relate to an exhaust assembly and a growth rate sensor within an epitaxial deposition process chamber. Methods of using them are also disclosed.

Background Art

[0002]

[0002] Semiconductor substrates are processed for a variety of applications including the manufacture of integrated devices and microdevices. One method of substrate processing involves depositing a material such as a dielectric material or a conductive metal on the upper surface of the substrate in a processing chamber. For example, epitaxy is a deposition process that typically grows a thin, ultra-high purity layer of silicon or germanium on the surface of a substrate. Materials can be deposited in a lateral flow chamber by flowing a process gas parallel to the surface of the substrate positioned on a support, pyrolyzing the process gas, and depositing the material from the process gas onto the substrate surface.

[0003]

[0003] Measurement of the film thickness of a processed substrate may be used in connection with a processing step. Film thickness measurement may be performed outside of the process chamber in which the processed substrate is processed, after the processing step has been performed (e.g., offline). In offline measurements, substrates that do not meet the specifications may not be used, and the process may need to be repeated several times to obtain measurement values that meet the specifications, which may be associated with inefficiencies and reduced throughput.

[0004]

[0004] Furthermore, it is difficult to perform film thickness measurement within the process chamber and during the processing step because the processing equipment within the process chamber may interfere with the measuring equipment, thereby preventing measurement accuracy. For example, the radiation from an infrared lamp and the heat emitted from the lamp may interfere with the measuring equipment.

[0005]

[0005] Accordingly, there is a need for an improved apparatus and method for in-situ measurement of film thickness in a processing chamber.

Summary of the Invention

[0006]

[0006] Embodiments of the present disclosure generally relate to in-situ monitoring of film growth in a processing chamber. More particularly, the embodiments disclosed herein relate to a sensor assembly for an epitaxial chamber and methods of using the same, as well as related apparatus.

[0007]

[0007] The present disclosure generally relates to a process chamber for semiconductor processing. In one embodiment, a growth rate sensor suitable for use during the manufacture of a semiconductor substrate is described. The growth rate sensor includes a body, an optically transparent window disposed at an end of the body, a silicon-containing coupon disposed inside the body and adjacent to the optically transparent window, a resistive heating element disposed inside the body and adjacent to the optically transparent window, a radiation sensor, and an optical fiber disposed between the radiation sensor and the optically transparent window.

[0008]

[0008] In another embodiment, an exhaust assembly suitable for use during the manufacture of a semiconductor substrate is described. The exhaust assembly includes one or more exhaust passage bodies, an exhaust collector disposed at a distal end of the one or more exhaust passage bodies, and a growth rate sensor disposed within the exhaust collector. The growth rate sensor includes an optically transparent window, a silicon-containing coupon disposed on a first side of the optically transparent window, and a resistive heating element disposed on a second side of the optically transparent window.

[0009]

[0009] In another embodiment, a process chamber suitable for use during processing of a semiconductor substrate is described. The process chamber includes a chamber body, a substrate support disposed within a process region of the chamber body, an upper window disposed above the substrate support and the process region, a lower window disposed below the substrate support and the process region, a gas injector disposed within the chamber body, an exhaust system disposed on the opposite side of the gas injector within the chamber body, and a growth rate sensor disposed within the exhaust system. The growth rate sensor includes an optically transparent window, a silicon-containing coupon disposed on a first side of the optically transparent window, and a resistive heating element disposed on a second side of the optically transparent window.

[0010]

[0010] In another embodiment, a non-transitory computer-readable medium is described. The non-transitory computer-readable medium stores instructions that, when executed by a processor, cause a computer system to perform several process steps. The process steps include monitoring the intensity of radiation reflected by or transmitted through a growth rate sensor. The growth rate sensor further includes an optically transparent window, a silicon-containing coupon disposed on a first side of the optically transparent window, and a resistive heating element disposed on a second side of the optically transparent window. The process steps further include heating the sensor coupon using an internal heating element while monitoring the intensity of the radiation, and determining the growth rate of a film deposited on the sensor coupon from a change in the intensity of the radiation.

[0011]

[0011] To better understand the features of the present disclosure described above, the present disclosure summarized above will be described more specifically with reference to embodiments illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings only show exemplary embodiments and should not be considered as limiting the scope thereof, and other equally effective embodiments are also acceptable.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Figure 5

DETAILED DESCRIPTION OF THE INVENTION

[0013]

[0017] For ease of understanding, the same reference numbers are used to denote the same elements common to the drawings as much as possible. The elements and features of one embodiment can be beneficially incorporated into other embodiments without further elaboration.

[0014]

[0018] The present disclosure relates to an exhaust assembly and a growth rate sensor within a semiconductor process chamber. The growth rate sensor performs in-situ monitoring of film growth in a processing chamber. As an example, the embodiments disclosed herein provide an apparatus and method for in-situ monitoring of film growth and film thickness measurement in a processing chamber such as an epitaxial deposition chamber.

[0015]

[0019] Embodiments disclosed herein provide a growth rate sensor positioned in the exhaust of a processing chamber such that an epitaxial film grows thereon. Film growth on the growth rate sensor simulates epitaxial film growth that occurs simultaneously on a substrate positioned within the processing chamber. The growth rate sensor is heated to have a temperature similar to that of the substrate in the process region of the processing chamber.

[0016]

[0020] Embodiments disclosed herein enable a substrate and / or coupon to have a temperature similar to that of a substrate being processed in a processing chamber in order to simulate film deposition characteristics of the substrate.

[0017]

[0021] Embodiments disclosed herein provide a sensor window and a substrate / coupon having a composition that enables backside spectral wavelength measurement in either the reflection mode, the transmission mode, or both the reflection mode and the transmission mode.

[0018]

[0022] Embodiments disclosed herein provide a sensor assembly that enables spectroscopic reflectivity measurements having low signal-to-noise ratio characteristics inside an epitaxial deposition chamber. The noise includes noise resulting from radiation of an infrared lamp in the epitaxial chamber. Embodiments of the sensor assembly described herein provide a sensor body having a radiation path therein. The sensor body is sealed from stray infrared light. Embodiments of the sensor assembly described herein provide a growth rate sensor that includes a resistive heating element for controlling the temperature of the growth rate sensor. The resistive heating element raises the temperature of the sensor window and advantageously raises the temperature of the sensor window and the substrate / coupon disposed thereon toward the temperature of the substrate being processed. Embodiments of the sensor assembly described herein provide an optical path isolated from the flow of process gas.

[0019]

[0023] The self-heating of a growth rate sensor using a resistive heating element or other heating element enables the growth rate sensor to be flexibly installed at various locations in the process chamber. To prevent the self-heating of the growth rate sensor from causing a decrease in detection sensitivity associated with a change in the position of the sensor, even if the installation location of the growth rate sensor is flexible, the improvement in sensitivity can be maintained. Also, by using a self-heating sensor as an in-situ growth rate sensor, the need for signal modulation is reduced. Further, the heating of the window and the substrate / coupon of the growth rate sensor assists in the regeneration of the substrate / coupon during the cleaning process in the process chamber.

[0020]

[0024] In some embodiments, the growth rate sensor is positioned inside the exhaust such that the gas flow is supplied across the growth rate sensor and the radiation emitted by a lamp or other radiation source in the process region is reduced. By reducing the background radiation, the wavelength range that can be used by the growth rate sensor in determining the growth rate can be made wider.

[0021]

[0025] A quartz body is disposed around at least a portion of the growth rate sensor to isolate the growth rate sensor from the deposition environment.

[0022]

[0026] FIG. 1 is a schematic view of a deposition chamber 100 according to an embodiment of the present disclosure. The deposition chamber 100 is an epitaxial deposition chamber. The deposition chamber 100 is used to grow an epitaxial film on a substrate such as a substrate 102. The deposition chamber 100 creates a cross-flow of precursors across the entire upper surface 150 of the substrate 102.

[0023]

[0027] The deposition chamber 100 includes an upper body 156, a lower body 148 disposed below the upper body 156, and a flow module 112 disposed between the upper body 156 and the lower body 148. The upper body 156, the flow module 112, and the lower body 148 form a chamber body. Disposed within the chamber body are a substrate support 106, an upper window 108, a lower window 110, a plurality of upper lamps 141, and a plurality of lower lamps 143. As shown, a controller 120 communicates with the deposition chamber 100 and is used to control the processes as described herein. The substrate support 106 is disposed between the upper window 108 and the lower window 110. The plurality of upper lamps 141 are disposed between the upper window 108 and the lid 154. The plurality of upper lamps 141 form part of an upper lamp module 155. The lid 154 may include a plurality of sensors (not shown) disposed therein for measuring the temperature within the deposition chamber 100. The plurality of lower lamps 143 are disposed between the lower window 110 and the floor 152. The plurality of lower lamps 143 form part of a lower lamp module 145. The upper window 108 is an upper dome and is formed of an energy transmissive material such as quartz. The lower window 110 is a lower dome and is formed of an energy transmissive material such as quartz.

[0024]

[0028] The process region 136 is formed between the upper window 108 and the lower window 110. The process region 136 has a substrate support 106 disposed therein. The substrate support 106 includes an upper surface on which the substrate 102 is disposed. The substrate support 106 is attached to a shaft 118. The shaft is connected to a motion assembly 121. The motion assembly 121 includes one or more actuators and / or adjustment devices that provide movement and / or adjustment of the shaft 118 and / or the substrate support 106 within the process region 136.

[0025]

[0029] The substrate support 106 may include lift pin holes 107 disposed therein. The lift pin holes 107 are sized to accommodate lift pins 132 for lifting the substrate 102 from the substrate support 106 either before or after the deposition process is performed. The lift pins 132 can rest on the lift pin stops 134 when the substrate support 106 descends from the process position to the transfer position.

[0026]

[0030] The flow module 112 includes a plurality of process gas inlets 114, a plurality of purge gas inlets 164, and one or more exhaust gas outlets 116. The plurality of process gas inlets 114 and the plurality of purge gas inlets 164 are disposed in the flow module 112 on the side opposite to the one or more exhaust gas outlets 116. One or more flow guides are disposed below the plurality of process gas inlets 114 and the one or more exhaust gas outlets 116. The flow guide is disposed above the purge gas inlet 164. A liner 163 is disposed on the inner surface of the flow module 112 to protect the flow module 112 from the reactive gases used during the deposition process. The process gas inlet 114 and the purge gas inlet 164 are positioned to flow gas parallel to the upper surface 150 of the substrate 102 disposed in the process region 136. The process gas inlet 114 is fluidly connected to a process gas source 151. The purge gas inlet 164 is fluidly connected to a purge gas source 162. The one or more exhaust gas outlets 116 are fluidly connected to an exhaust pump 157.

[0027]

[0031] One or more exhaust gas outlets 116 are further connected to, or include, an exhaust system 178. The exhaust system 178 fluidly connects the one or more exhaust gas outlets 116 and an exhaust pump 157. The exhaust system 178 described herein includes one or more growth monitors 160a, 160b. Each of the one or more growth monitors 160a, 160b is coupled to an optical module 167a, 167b. Thus, the first growth monitor 160a is coupled to the first optical module 167a, and the second growth monitor 160b is coupled to the second optical module 167b. A first optical fiber cable 165a optically couples the first growth monitor 160a and the first optical module 167a. A second optical fiber cable 165b optically couples the second growth monitor 160b and the second optical module 167b.

[0028]

[0032] FIG. 2 is a cross-sectional plan view showing a deposition chamber 100 of FIG. 1 according to an embodiment of the present disclosure. The deposition chamber 100 includes an injector 202 disposed on the opposite side of the exhaust system 178. The injector 202 includes a process gas inlet 114 and is fluidly coupled to a process gas source 151. The injector 202 may be disposed through at least a portion of the flow module 112 or may be a part of the flow module 112. The exhaust system 178 is disposed on the side of the injector 202 opposite the process region 136. The exhaust system 178 is formed through the flow module, or attached to the flow module, or is a part of the flow module.

[0029]

[0033] The exhaust system 178 further includes at least one exhaust passage main body 204a, 204b. The exhaust passage main bodies 204a, 204b form an exhaust passage for the gas that exits the process region 136 before entering the exhaust collector 206. As shown in FIG. 2, there are a first exhaust passage main body 204a and a second exhaust passage main body 204b. The first exhaust passage main body 204a and the second exhaust passage main body 204b are mirror images and may be similar in size and configuration. In other embodiments, there may be more or fewer exhaust passage main bodies 204a, 204b. In some embodiments, the exhaust passage main bodies are such that the two exhaust passage main bodies 204a, 204b are integrated into a single main body and there is only one. In still other embodiments, there may be three or more exhaust passage main bodies, for example, three exhaust passage main bodies 204a, 204b. The size and configuration of the exhaust passage main bodies 204a, 204b can be changed according to the size and process of the deposition chamber 100.

[0030]

[0034] Both the first exhaust passage main body 204a and the second exhaust passage main body 204b are coupled to the exhaust collector 206 at the ends of the exhaust passage main bodies 204a, 204b on the side opposite to the process region 136. The exhaust collector 206 is configured to collect the exhaust from the first exhaust passage main body 204a and the second exhaust passage main body 204b. The exhaust collector 206 narrows as it moves away from the exhaust passage main bodies 204a, 204b. Growth monitors 160a, 160b are disposed within the exhaust collector 206. The growth monitors 160a, 160b are disposed adjacent to the inlets from the exhaust passage main bodies 204a, 204b to the exhaust collector 206. The growth monitors 160a, 160b can be disposed at various positions within the exhaust collector 206 and / or the exhaust passage main bodies 204a, 204b. Additional growth monitors 208a, 208b, 208c may be disposed within the exhaust collector 206 and / or the exhaust passage main bodies 204a, 204b. The additional growth monitors 208a, 208b, 208c may be the same as the growth monitors 160a, 160b, or may be different types of growth monitors such as crystal oscillator growth monitors.

[0031]

[0035] FIG. 3 is a cross-sectional side view showing the exhaust system 178 of the deposition chamber 100 of FIG. 1. Inside each exhaust passage body 204a, 204b, there is an exhaust plenum. The exhaust plenum 312a of the first exhaust passage body 204a is shown, and a similar second exhaust plenum is disposed through the second exhaust passage body 204b. As shown in FIG. 3, the exhaust plenum 312a of the exhaust system 178 extends through at least a portion of the flow module 112 such that the exhaust plenum 312a extends through the side wall of the flow module 112 and interacts with the process region 136.

[0032]

[0036] Gas is exhausted from the process region 136 into the exhaust plenum 312a. From the exhaust plenum 312a, the gas further flows into the collector plenum 316. The collector plenum 316 is a plenum disposed within the exhaust collector 206.

[0033]

[0037] One or more growth monitors 160a, 160b are located either within the exhaust plenum 312a or within the collector plenum 316. The first growth monitor 160a is disposed within the exhaust collector 206 and the inner upper surface 324 of the collector plenum 316. The second growth monitor 160b is disposed within the exhaust collector 206 and the inner lower surface 327 of the collector plenum 316. Instead of, or in addition to, the placement of the growth monitors 160a, 160b within the exhaust collector, one or more similar growth monitors are positioned inside the inner upper surface 326 or the inner lower surface 329 of the exhaust passage bodies 204a, 204b and are connected to the exhaust plenum 312a. By disposing the growth monitors 160a, 160b on either the inner upper surface 324 or the inner lower surface 327 of the collector plenum 316, the growth monitors 160a, 160b can be deposited on the sensor coupons 362a, 362b without blocking the flow path of the exhaust gas. The first growth monitor 160a includes a sensor coupon 362a that is oriented downward and faces the inner lower surface 328. The second growth monitor 160b includes a second sensor coupon 362b that is oriented upward and faces the inner upper surface 324.

[0034]

[0038] Before the exhaust gas is removed from the exhaust collector 206 through the duct opening 306 of the exhaust duct 323, it passes over the growth monitors 160a, 160b and enters the collector plenum 316. The duct opening 306 is disposed in a portion of the collector plenum 316 that is opposite to an end portion of the collector plenum 316 adjacent to the exhaust plenum 312a and the exhaust passage main bodies 204a, 204b. The duct opening 306 is configured to be able to discharge the exhaust gas in the exhaust collector 206 to the exhaust pump 157 through the exhaust duct 323. The rear side wall 321 of the exhaust plenum 312a may be disposed adjacent to the duct opening 306 and configured to guide gas into the duct opening 306. The duct opening 306 is disposed to penetrate the inner lower surface 327 of the collector plenum 316 and open into the exhaust duct 323. The exhaust duct 323 extends downward from the duct opening 306 and is fluidly connected to the exhaust pump 157.

[0035]

[0039] Figures 4A - 4D are diagrams showing different embodiments of growth monitors 160a, 160b, 160c, 160d for use within the deposition chamber of FIG. 1. Each of the growth monitors 160a, 160b, 160c, 160d is configured to measure changes in the transmission and / or reflection of radiation passing through a coupon such as sensor coupon 362a of FIGS. 4A and 4C or sensor coupon 362b of FIGS. 4B and 4D. Changes in the transmission and / or reflection of radiation passing through the coupon are caused by the growth of film 476 on sensor coupons 362a, 362b. As film 476 grows, the wavelength and intensity of the radiation passing through or reflected from sensor coupons 362a, 362b change and are measured to determine the growth rate of film 476. The growth rate of film 476 can be correlated to the growth rate on a substrate such as substrate 102 within deposition chamber 100. Growth monitors 160a, 160b, 160c, 160d are heated using one or more heating elements. The one or more internal heating elements may be resistive heating elements, Peltier elements, infrared (IR) heating elements, or heating fluid conduits. Other heating devices are also envisioned and can be used as the one or more internal heating elements. The one or more heating elements are configured to be adjacent to sensor coupons 362, 362b.

[0036]

[0040] FIG. 4A is a diagram showing a first embodiment of growth monitor 160a. The growth monitor 160a of FIG. 4A includes an outer body 402 and an optically transparent inner body 463. Growth monitor 160a is positioned such that growth monitor 160a is disposed through inner upper surface 324. Growth monitor 160a is also configured to include a radiation source 434 disposed within a first optical module 167a. By disposing radiation source 434 together with radiation sensor 436 within the first optical module 167a, the growth monitor 160a of FIG. 4A becomes a reflection-type monitor and is capable of measuring the radiation reflected by sensor coupon 362a from the radiation beam emitted by radiation source 434. The first optical module 167a can also use background radiation passing through sensor coupon 362a from collector plenum 316 instead of radiation source 434.

[0037]

[0041] The radiation sensor 436 may include an optical spectrometer. Other radiation sensors 436 are also envisioned and can be used. The radiation measured by the radiation sensor 436 is from about 0.5 μm to about 6 μm, such as from about 1 μm to about 5 μm, such as from about 2 μm to about 4 μm. The radiation emitted by the radiation source 434 is from about 0.5 μm to about 6 μm, such as from about 1 μm to about 5 μm, such as from about 2 μm to about 4 μm.

[0038]

[0042] Both the outer body 402 and the optically transparent inner body 463 form the body of the growth monitor 160a. The outer body 402 is disposed such that the outer body 402 penetrates the inner upper surface 324 and the bottom of the growth monitor 160a is exposed to the exhaust gas passing through the collector plenum 316 and the exhaust system 178, and is disposed through the wall of the exhaust system 178. The transparent inner body 463 is transparent to radiation within a predetermined range. In some embodiments, the transparent inner body 463 has a transmittance of 90% or more for radiation having a wavelength from about 0.2 μm to about 5.0 μm, such as from about 0.5 μm to about 5.0 μm, such as from about 1.0 μm to about 4.5 μm. The wavelength for which the transparent inner body 463 is transparent may be at least partially affected by the type of heating source. The transparent inner body 463 may be transparent to the radiation emitted by the radiation source 434 and the radiation received by the radiation sensor 436. A part of the transparent inner body 463 is formed by the optically transparent window 462a. The optically transparent window 462a is disposed adjacent to the collector plenum 316. The optically transparent window 462a may be of the same material as, or a different material from, the remaining portion of the transparent inner body 463.

[0039]

[0043] The sensor coupon 362a is disposed adjacent to an optically transparent window 462a and a transparent inner body 463. The sensor coupon 362a includes a deposition surface 428a and a back surface 430a. The deposition surface 428a is oriented toward the inner lower surface 327. A film 476 grows on the deposition surface 428a during a processing step and correlates with film growth on a substrate within a process region of a semiconductor processing chamber such as the deposition chamber 100.

[0040]

[0044] In the growth monitor 160a, the sensor coupon 362a is fixed to the transparent inner body 463 using a cover 404. The cover 404 is configured to partially surround the sensor coupon 362a such that the cover 404 can fix the sensor coupon 362a. As shown in FIG. 4A, the outer edge of the deposition surface 428a of the sensor coupon 362a is covered by the cover 404 and held to fix the sensor coupon 362a. The central portion of the deposition surface 428a of the sensor coupon 362a remains uncovered and is exposed to the collector plenum 316.

[0041]

[0045] A backside sensor plenum 408 is formed above the sensor coupon 362a between the back surface 430a and the optically transparent window 462a. The backside sensor plenum 408 reduces the pressure that may be applied to the sensor coupon 362a by the cover 404 when the cover 404 holds the back surface 430a coplanar with the optically transparent window 462a. When using the backside sensor plenum 408, a pressure difference may occur between the backside sensor plenum 408 and the collector plenum 316 during processing. Therefore, in order to prevent damage to the sensor coupon 362a due to the pressure difference, one or more equalization ports (not shown) are disposed between the outer surface of the transparent inner body 463 and the backside sensor plenum 408 to enable equalization of the pressure between the backside sensor plenum 408 and surrounding regions such as the collector plenum 316.

[0042]

[0046] Cover 404 may include a coupon transfer opening 406. The coupon transfer opening 406 may be positioned at either an upstream position or a downstream position. The coupon transfer opening 406 is configured to enable the transfer of the sensor coupon 362a in and out of the cover 404. Thus, the bottom surface of the cover 404 functions as a shelf, and the coupon transfer opening 406 may have a surface that is coplanar with the support surface of the cover 404 that supports the sensor coupon 362a. The coupon transfer opening 406 has a width that is at least the same as the width of the sensor coupon 362a. Thus, the coupon transfer opening 406 is a rectangular or arcuate opening that penetrates the transparent inner body 463. The coupon transfer opening 406 can be patched or filled before positioning the transparent inner body 463 inside the collector plenum 316. The patch or filler may be a plug. The material of the patch or filler is the same material as the transparent inner body 463 and can be coated or positioned using a high-temperature coating process.

[0043]

[0047] In one or more examples, the thickness of the sensor coupon 362a is about 400 μm or less, such as from about 200 μm to about 400 μm, such as from about 250 μm to about 350 μm, such as about 300 μm. The thickness of the sensor coupon 362a is configured to reduce the attenuation of radiation passing therethrough. In one or more examples, the sensor coupon 362a has a crystalline structure. The sensor coupon 362a with a crystalline structure advantageously increases the radiation transmission and thermal conductivity compared to the corresponding amorphous material. Thus, heat and radiation can be easily transmitted between the optically transparent window 462a and the sensor coupon 362a. Thus, the heating of the sensor coupon 362a is more predictable and uniform, and the radiation from the radiation source easily passes through the sensor coupon 362a and is measured. In one embodiment that can be combined with other embodiments, the sensor coupon 362a is a silicon-containing coupon. In one embodiment, the sensor coupon 362a is formed from silicon carbide (e.g., SiC). Other materials are also contemplated for the sensor coupon 362a. The silicon carbide sensor coupon 362a is advantageous because it provides a spectral transmission signal for any silicon-based doped or undoped film deposited thereon, as opposed to a sensor coupon 362a formed only from silicon that does not provide a spectral transmission signal for a silicon-based film. In one embodiment that can be combined with other embodiments, the sensor coupon 362a is crystalline silicon carbide. The crystalline structure of the sensor coupon 362a is 6H, 4H, 3C, or a combination thereof.

[0044]

[0048] The deposition surface 428a of the sensor coupon 362a has a roughness of less than 3 nm, for example less than 2 nm, for example less than 1 nm. In one embodiment, which can be combined with other embodiments, the transparent inner body 463 and the optically transparent window 462a are formed from silicon carbide (e.g., SiC), quartz (e.g., black quartz, black opaque quartz, or white opaque quartz), or a combination thereof. Other materials are also envisioned and can be used within the transparent inner body 463. The material and shape of the transparent inner body 463 are configured to reduce stray light radiation within the transparent inner body 463 that passes through the transparent window 462a. The stray light radiation is reduced at wavelengths from about 300 nm to about 1000 nm, for example from about 400 nm to about 800 nm.

[0045]

[0049] The outer body 402 is a metallic material and can be configured to absorb any radiation leaking from the transparent inner body 463. The outer body 402 is a metallic material such as stainless steel. Other materials are envisioned and can be used within the outer body 402. In some embodiments, the inner surface of the outer body 402 is gold-plated. Other materials are also envisioned and can be used as plating or a film within the outer body 402. Both the outer body 402 and the transparent inner body 463 have a cylindrical outer wall and a cylindrical inner wall. In some embodiments, the inner and outer walls of the outer body 402 and the transparent inner body 463 are prisms such as rectangular prisms, pentagonal prisms, or hexagonal prisms. Other prisms can also be used.

[0046]

[0050] The internal heating element 411 is disposed within the outer body 402 and the transparent inner body 463. The internal heating element 411 may be a resistive heating element, a Peltier element, or a heating fluid conduit. Other heating devices are also contemplated and can be used as the internal heating element 411. In the embodiments described herein, the internal heating element 411 is a resistive heating element. The internal heating element 411 provides rapid and accurate control of the temperature of the sensor coupon 362a. In some embodiments, the internal heating element 411 can heat the sensor coupon 362a and control the heating of the sensor coupon 362a from about 300°C to about 1200°C, such as from about 400°C to about 1000°C, such as from about 500°C to about 900°C. The temperature of the sensor coupon 362a is controlled with an accuracy of less than about 10°C, such as less than about 7°C, such as less than about 5°C.

[0047]

[0051] The internal heating element 411 includes a low resistance element 412 and a high resistance element 410. The high resistance element 410 has a higher resistivity than the low resistance element 412, and the resistivity of the high resistance element 410 is more than 10 times higher, such as more than 20 times higher, such as more than 50 times higher than the resistivity of the low resistance element 412. The high resistance element 410 is disposed adjacent to the optically transparent window 462a and the sensor coupon 362a. The high resistance element 410 has a resistivity of from about 10 3 Ω·cm to about 10 6 Ω·cm, such as from about 2000 Ω·cm to about 10000 Ω·cm, such as from about 10 4 Ω·cm to about 10 5 Ω·cm, such as from about 10 5 Ω·cm to about 10 6 Ω·cm. The low resistance element 412 has a resistivity of from about 0.1 Ω·cm to about 100 Ω·cm, such as from about 1 Ω·cm to about 10 Ω·cm, such as from about 10 Ω·cm to about 100 Ω·cm. The low resistance element 412 is configured to transfer power from one or more power supplies 426 to the high resistance element 410. The high resistance element 410 is configured to be heated when power is applied thereto.

[0048]

[0052] The temperature measurement device 414 is disposed adjacent to and / or in contact with the high resistance element 410. The temperature measurement device 414 is configured to measure the temperature of one or both of the optically transparent window 462a and the sensor coupon 362a. The temperature measurement device 414 of the growth monitor 160 is a thermocouple or a pyrometer. Other temperature measurement devices are also envisioned and can be used as the temperature measurement device 414. The temperature measurement device 414 is coupled to the temperature measurement receiver 418 by wiring 416. The temperature measurement receiver 418 is configured to apply power to the thermocouple and measure the voltage of the thermocouple and the corresponding voltage change. In some embodiments, the temperature measurement receiver 418 is integrated into the controller 120. In some embodiments, the bandgap absorption of the sensor coupon 362a and / or the optically transparent window 462 is measured and the temperature of the optically transparent window 462 and the sensor coupon 362a is determined. This may be an addition to or an alternative to the temperature measurement device 414.

[0049]

[0053] The growth monitor 160a further includes one or more lenses 424 and one or more mirrors 422. The lenses 424 and the mirrors 422 are configured to collimate and direct radiation between the sensor coupon 362a and the radiation sensor 436. A partition 432 is positioned between the lower end portion and the upper end portion of the growth monitor 160a. The lower end portion includes the high resistance element 410, the low resistance element 412, the sensor coupon 362a, the optically transparent window 462a, the optically transparent inner body 463, and the temperature measurement device 414. The upper end portion includes one or more lenses 424 and one or more mirrors 422. The partition can reduce stray radiation that interacts with the one or more lenses 424 and the one or more mirrors 422.

[0050]

[0054] One or more optical fiber cables 420, 165a are arranged along the radiation measurement path 425. The first optical fiber cable 165a is arranged between the first optical module 167a and the body of the growth monitor 160a. The second optical fiber cable 420 is arranged between the optically transparent window 462 / sensor coupon 362a and the mirror 422 / lens 424. In some embodiments, the second optical fiber cable 420 is omitted.

[0051]

[0055] FIG. 4B is a diagram showing a second embodiment of the growth monitor 160b. The growth monitor 160b of FIG. 4B is similar to the growth monitor 160a of FIG. 4A, but the growth monitor 160b is arranged to penetrate the inner lower surface 327 of the exhaust collector 206.

[0052]

[0056] The growth monitor 160b is also configured to include a radiation source 434 and a radiation sensor 436 arranged in the second optical module 167b. By arranging the radiation source 434 and the radiation sensor 436 together in the second optical module 167b, the growth monitor 160b of FIG. 4B becomes a reflection type monitor, and it is possible to measure the radiation reflected by the sensor coupon 362b from the radiation beam emitted by the radiation source 434. The second optical module 167b can also use the background radiation passing through the sensor coupon 362b from the collector plenum 316 instead of the radiation source 434.

[0053]

[0057] In growth monitor 160b, sensor coupon 362b is arranged such that deposition surface 428 is oriented upward so that deposition surface 428 faces inner upper surface 324. Sensor coupon 362b is arranged on optically transparent window 462b such that the back surface 430b of sensor coupon 362b is arranged on optically transparent window 462b. By positioning sensor coupon 362b on optically transparent window 462b, since gravity holds sensor coupon 362b on optically transparent window 462b, it becomes possible to eliminate cover 404 of growth monitor 160a in FIG. 4A. Sensor coupon 362b is arranged in pocket 435. Pocket 435 is a concave opening and is configured to receive sensor coupon 362b. Optically transparent window 462b is the bottom surface of pocket 435. Since sensor coupon 362b is arranged on the same plane as optically transparent window 462b, there is no backside sensor plenum 408 or equalization ports 406a, 406b either. For this reason, the entire deposition surface 428 is exposed to the exhaust gas.

[0054]

[0058] FIG. 4C is a diagram showing a third embodiment of growth monitor 160c. Growth monitor 160c in FIG. 4C is the same as growth monitor 160a in FIG. 4A, but radiation source 434 is separated from radiation sensor 436 and is arranged such that radiation passes through sensor coupon 362a. Therefore, growth monitor 160c measures the radiation that has passed through sensor coupon 362a instead of the radiation reflected from sensor coupon 362a. Radiation outlet 440 is arranged to penetrate inner lower surface 327 of exhaust collector 206.

[0055]

[0059] FIG. 4D is a diagram showing a fourth embodiment of the growth monitor 160d. The growth monitor 160d of FIG. 4D is similar to the growth monitor 160b of FIG. 4B, but the radiation source 434 is separated from the radiation sensor 436 and is arranged such that radiation passes through the sensor coupon 362b. Therefore, the growth monitor 160d measures the radiation that has passed through the sensor coupon 362b rather than the radiation reflected from the sensor coupon 362b. The radiation outlet 440 is arranged to penetrate the inner upper surface 324 of the exhaust collector 206.

[0056]

[0060] FIG. 5 is a schematic diagram showing a method 500 for processing a substrate. In one or more examples, the method 500 may be performed using one of the exemplary processing chambers and / or sensor assemblies disclosed herein. In one or more examples, the method 500 may be in the form of instructions stored on a computer-readable medium (e.g., a memory) and, when executed by a processor (e.g., a CPU) of the system, cause the system to perform the method 500. The computer-readable medium and the corresponding system are part of a controller such as the controller 120.

[0057]

[0061] In process 502, a film is simultaneously deposited on a substrate such as substrate 102 disposed within a processing chamber such as deposition chamber 100, and on a sensor coupon of a growth rate sensor such as sensor coupon 362a or 263b. Depositing the film includes flowing one or more precursors or process gases from a process gas source and heating the substrate. The process gas is flowed over the substrate surface as a side injection while rotating the substrate on a substrate support or susceptor. In process 504, the sensor coupon, and an optically transparent window to which the sensor coupon is coupled, are heated using an internal heating element such as internal heating element 411 within the growth rate sensor. In one embodiment that can be combined with other embodiments, heating the sensor coupon and the optically transparent window at least partially through the internal heating element includes applying power to a resistive heating element disposed within the growth rate sensor. The internal heating element is heated to a predetermined temperature similar to the temperature of the substrate being processed within the process region. The difference between the substrate temperature and the coupon temperature is less than about 50°C, such as less than about 30°C, such as less than about 20°C during process 504. The temperature of the coupon and / or the internal heating element is measured individually using a temperature measuring device such as a thermocouple.

[0058]

[0062] In process 506, the intensity of radiation reflected by or transmitted through the sensor window is measured using an optical spectrometer that is part of a radiation sensor. During process 506, radiation may also be emitted by a radiation source. The radiation source may be a laser or an optical fiber. The radiation measured by the optical spectrometer and emitted by the radiation source is from about 0.5 μm to about 6 μm, such as from about 1 μm to about 5 μm, such as from about 2 μm to about 4 μm.

[0059]

[0063] In operation 508, based on the measured radiation intensity, at least one of the thickness or growth rate of the film deposited on the crystal sensor window is determined. In one embodiment that can be combined with other embodiments, determining the thickness and / or growth rate includes measuring a plurality of radiation intensity values of radiation (which may include transmitted radiation and / or reflected radiation) over one or more time intervals. The plurality of radiation intensity values are correlated with reference data or physical models based on Fresnel's equations of electromagnetic wave reflection to determine the growth rate over one or more time intervals. The growth rate and / or thickness (such as a change in thickness) may correspond to a change in radiation intensity over one or more time intervals. In one or more examples, the film thickness can be determined using the growth rate at a particular time interval.

[0060]

[0064] Each of the growth monitors 160a, 160b, 160c, 160d described herein can be used with the deposition chamber 100 described herein or an additional version of a semiconductor processing chamber. In some embodiments, the growth monitors 160a, 160b, 160c, 160d are disposed in a semiconductor processing chamber different from those described herein, such as an atomic layer deposition (ALD) chamber, a physical vapor deposition (PVD) chamber, and other versions of a chemical vapor deposition (CVD) chamber. By disposing the growth monitors 160a, 160b, 160c, 160d, the amount of stray light radiation from a lamp or other heating element is reduced compared to when the growth monitors 160a, 160b, 160c, 160d are located inside the process region 136 of the deposition chamber 100. However, by disposing the growth monitors 160a, 160b, 160c, 160d inside the exhaust, the growth monitors 160a, 160b, 160c, 160d are not heated by the same heating element or lamp as the substrate 102. If the growth monitors 160a, 160b, 160c, 160d are not at a temperature similar to that of the substrate 102, the quality of film growth and film removal from sensor coupons such as sensor coupons 362a, 362b, etc. deteriorates. Accordingly, the growth monitors 160a, 160b, 160c, 160d described herein have an internal heating element 411 disposed therein.

[0061]

[0065] The internal heating element 411 enables the growth monitors 160a, 160b, 160c, and 160d to be maintained at the same temperature as the substrate 102 while reducing background radiation. By using the self-heating type growth monitors 160a, 160b, 160c, and 160d, it becomes further possible to flexibly arrange the growth monitors 160a, 160b, 160c, and 160d throughout the deposition chamber 100. Therefore, the growth monitors 160a, 160b, 160c, and 160d can be arranged in different parts of the exhaust system 178. By arranging the growth monitors 160a, 160b, 160c, and 160d in the exhaust system 178, the complexity of the system inside the process region 136 is further reduced compared to the case where the growth monitors 160a, 160b, 160c, and 160d are arranged inside the process region 136.

[0062]

[0066] In an embodiment of the present disclosure, a process chamber suitable for use during semiconductor substrate processing is described. The process chamber includes a chamber body, a substrate support disposed in the process region of the chamber body, an upper window disposed above the substrate support and the process region, a lower window disposed below the substrate support and the process region, a gas injector disposed in the chamber body, an exhaust system disposed on the opposite side of the gas injection in the chamber body, and a growth rate sensor disposed in the exhaust system. The growth rate sensor includes an optically transparent window, a silicon-containing coupon disposed on a first side surface of the optically transparent window, and a resistive heating element disposed on a second side surface of the optically transparent window.

[0063]

[0067] In some embodiments, the growth rate sensor further includes a body, a radiation sensor, and an optical fiber disposed between the radiation sensor and the optically transparent window. The optically transparent window is disposed at an end of the body, and the resistive heating element is disposed inside the body. The body further includes an outer body and an optically transparent inner body, and the optically transparent window is a part of the optically transparent inner body.

[0064]

[0068] Although the foregoing is directed to embodiments of the present disclosure, it is possible to devise additional embodiments of the present disclosure without departing from its basic scope as determined by the following claims.

Claims

1. A growth rate sensor suitable for use during the manufacture of a semiconductor substrate, comprising: a body; an optically transparent window disposed at an end of the body; a silicon-containing coupon disposed inside the body and adjacent to the optically transparent window; a resistive heating element disposed inside the body and adjacent to the optically transparent window; a radiation sensor; and an optical fiber disposed between the radiation sensor and the optically transparent window. A growth rate sensor.

2. The body further comprises: an outer body; and an optically transparent inner body, wherein the optically transparent window is part of the optically transparent inner body. The growth rate sensor according to claim 1.

3. The growth rate sensor according to claim 1, further comprising a radiation source configured to emit radiation that passes through or is reflected from the silicon-containing coupon and is measured by the radiation sensor.

4. The growth rate sensor according to claim 1, further comprising one or more of a mirror or a lens disposed between the radiation sensor and the optically transparent window.

5. The growth rate sensor according to claim 1, further comprising a thermocouple adjacent to the resistive heating element.

6. The growth rate sensor according to claim 1, further comprising a cover that partially surrounds and fixes the silicon-containing coupon.

7. The growth rate sensor according to claim 6, wherein a plenum is disposed between the optically transparent window and the silicon-containing coupon.

8. The growth rate sensor according to claim 7, wherein one or more equalization ports are disposed between an outer surface of the body and the plenum to enable equalization of pressure between the plenum and the surrounding area.

9. The growth rate sensor according to claim 1, wherein the silicon-containing coupon is a silicon carbide substrate.

10. An exhaust assembly suitable for use during the manufacture of a semiconductor substrate, comprising: one or more exhaust passage bodies; an exhaust collector disposed at a distal end of the one or more exhaust passage bodies; and a growth rate sensor disposed inside the exhaust collector, the growth rate sensor comprising: an optically transparent window; a silicon-containing coupon disposed on a first side of the optically transparent window; and a resistive heating element disposed on a second side of the optically transparent window. A growth rate sensor. An exhaust assembly.

11. The growth rate sensor further comprises a main body, a radiation sensor, an optical fiber disposed between the radiation sensor and the optically transparent window, the optically transparent window being disposed at an end of the main body, and the resistive heating element being disposed inside the main body, the optical fiber The exhaust assembly according to claim 10, comprising

12. The exhaust assembly according to claim 10, further comprising an exhaust duct coupled to the exhaust collector.

13. The exhaust assembly according to claim 12, wherein the growth rate sensor is disposed on an inner upper surface of the exhaust collector.

14. The exhaust assembly according to claim 13, wherein a radiation source is disposed to penetrate an inner lower surface of the exhaust collector and configured to emit radiation toward the silicon-containing coupon.

15. The exhaust assembly according to claim 12, wherein the growth rate sensor is disposed on an inner lower surface of the exhaust collector.

16. The exhaust assembly according to claim 15, wherein a radiation source is disposed to penetrate an inner upper surface of the exhaust collector and configured to emit radiation toward the silicon-containing coupon.

17. The exhaust assembly according to claim 10, wherein the silicon-containing coupon is exposed in an exhaust region within the exhaust collector.

18. A non-transitory computer-readable medium that, when executed by a processor, causes the system to monitor the intensity of radiation reflected by or transmitted through a growth rate sensor, the growth rate sensor comprising an optically transparent window, a silicon-containing coupon disposed on a first side of the optically transparent window, a resistive heating element disposed on a second side of the optically transparent window monitor the intensity of radiation reflected by or transmitted through the growth rate sensor, heat the sensor coupon using the resistive heating element during monitoring of the intensity of the radiation, determine the growth rate of a film deposited on the sensor coupon from a change in the intensity of the radiation A non-transitory computer-readable medium storing instructions to cause the above to be performed.

19. The medium according to claim 18, wherein the growth rate sensor is positioned in an exhaust region of a process chamber.

20. The medium according to claim 19, wherein the growth rate of the film deposited on the sensor coupon is correlated with the growth rate on a substrate within the processing region of the process chamber.

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