In-situ EPI growth rate control for crystal thickness using parametric resonance sensing

Abstract

A method and apparatus for processing a semiconductor substrate are described herein. The apparatus includes one or more growth monitors disposed within an exhaust system of the deposition chamber. The growth monitor is a parametric resonance monitor, and the growth monitor is configured to measure a thickness of a film grown on the growth monitor while the substrate is being processed within the deposition chamber. The growth monitor is connected to a controller that adjusts the settings of the heating device and the airflow device during the processing operation. Measurements from a growth monitor and other sensors within the deposition chamber are used to adjust a processing chamber model of the deposition chamber when processing a substrate in the deposition chamber.

Description

Technical Field

[0001] Embodiments of the present application generally relate to apparatus and methods for manufacturing semiconductor devices. More specifically, the apparatus disclosed herein relates to an exhaust assembly and a growth rate sensor within a semiconductor processing chamber. Further disclosed herein are methods of using the exhaust assembly and the growth rate sensor. Background Art

[0002] Semiconductor substrates are processed for a wide variety of applications; the wide variety of applications includes the fabrication of integrated devices and micro devices. During processing, the substrate is located on a susceptor within a processing chamber. The susceptor is supported by a support shaft that is rotatable about a central axis. Precise control of the heating source heats the substrate uniformly within tight tolerances. The temperature of the substrate can affect the uniformity of the material deposited on the substrate.

[0003] The ability to monitor growth / deposition thickness within a processing chamber has a significant impact on throughput and production yield. Currently, in-situ monitoring of growth / deposition thickness is not generally performed in epitaxial reactors. Currently, the process is timed to achieve the desired thickness and then the thickness is measured off-site. Traditional attempts to include sensors within the processing chamber result in limited resolution, and the addition of sensors increases downtime of the processing chamber and increases the cost of ownership. Attempts to offset these costs have not yet provided a direct measurement of quality or. Substrates processed between calibration operations and measurement operations also have less accurate deposition rates due to changes in chamber conditions. Current sensors within the processing chamber include pyrometers and pressure sensors; pyrometers and pressure sensors do not provide the required accuracy in determining film growth.

[0004] Therefore, there is a need for improved growth rate monitoring. Summary of the invention

[0005] The present application relates generally to apparatus and methods for manufacturing semiconductor devices. More specifically, the apparatus disclosed herein relates to an exhaust assembly and a growth rate sensor within a semiconductor processing chamber. Further disclosed herein are methods of using the exhaust assembly and the growth rate sensor.

[0006] In another embodiment, an exhaust system for substrate processing is disclosed herein. The exhaust system includes a first exhaust plenum, a first exhaust inlet opening, a first plurality of fins, a first exhaust outlet opening, a first baffle, and at least one growth monitor, wherein the first exhaust inlet opening is fluidly connected to the first exhaust plenum, the first plurality of fins are disposed in the first exhaust plenum adjacent to the first exhaust inlet opening, the first exhaust outlet opening is fluidly connected to the first exhaust plenum, the first baffle is disposed adjacent to the first exhaust outlet opening and is configured to narrow the width of the first exhaust plenum, and the at least one growth monitor is disposed downstream of the first baffle. The growth monitor is configured to measure the thickness of the material deposited on the growth monitor. At least one growth monitor is a parametric resonance sensor.

[0007] In another embodiment, a processing system suitable for semiconductor substrate processing. The processing system includes a chamber body forming a processing volume, a substrate support, an upper window, a lower window, an injector, and an exhaust system. The substrate support is disposed within the processing volume of the chamber body. The upper window is disposed above the substrate support, and the lower window is disposed below the substrate support. The upper window and the lower window define the processing volume. The injector is disposed through a side of the chamber body, and the injector is configured to introduce a processing gas into the processing volume. The exhaust system is disposed through a second side of the chamber body opposite the injector. The exhaust system includes at least one growth monitor, and the at least one growth monitor is configured to measure the thickness of a material deposited on the growth monitor. The growth monitor is a parametric resonance sensor.

[0008] In another embodiment, a controller for a processing system storing instructions is disclosed herein. The controller, when executed by a processor, causes the system to process a substrate in a processing chamber by flowing a processing gas from a processing gas inlet through a processing volume, depositing the gas on the substrate, and exhausting the processing gas through an exhaust system. The exhaust system further includes a growth monitor. The growth monitor includes a parametric resonance sensor. The controller further causes the system to deposit the processing gas on the growth monitor, measure film growth on the growth monitor, calculate a film growth rate on the substrate, and adjust a processing chamber parameter. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to be able to understand the above-mentioned features of the present application in detail, a more specific description of the present application, which is briefly summarized above, can be obtained by reference to the embodiments; some of the embodiments are shown in the accompanying drawings. However, it should be noted that the drawings only illustrate exemplary embodiments; the drawings should not be considered as limiting the scope, because the present application may admit other equally effective embodiments.

[0010] Figure 1 is a schematic diagram of a deposition chamber according to some embodiments.

[0011] Figure 2 According to some embodiments Figure 1 A cross-sectional plan view of a deposition chamber.

[0012] Figure 3A According to some embodiments Figure 1 A cross-sectional plan view of the exhaust system of a deposition chamber.

[0013] Figure 3B According to some embodiments Figure 1 Cross-sectional side view of the exhaust system of a deposition chamber.

[0014] Figure 4A and Figure 4B Shown in Figure 1 Two embodiments of a growth monitor for use in a deposition chamber.

[0015] Figure 5 According to some embodiments Figure 1 Schematic diagram of the controls used within the deposition chamber.

[0016] Figure 6 Shows the adjustment according to the embodiment of the present application Figure 1 The method of processing conditions within a deposition chamber.

[0017] Figure 7 shows measurements according to some embodiments Figure 1 A method of measuring the thickness of a material on a substrate within a deposition chamber.

[0018] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. DETAILED DESCRIPTION

[0019] The present application relates to an exhaust assembly and a growth rate sensor within a semiconductor processing chamber. The growth rate sensor is a parametric resonant film thickness monitor, and the growth rate sensor is capable of measuring the film thickness on the growth rate sensor. The film thickness on the growth rate sensor is equivalent to the growth rate on the substrate within the processing chamber. The thickness measurement can then be used to adjust one or more process controls within the processing volume of the processing chamber and improve film growth across the substrate.

[0020] The location and number of parametric resonance monitors provide increased sensitivity and sensor lifecycle. The configuration of the exhaust system around the parametric resonance monitors further enables gas flow within the process volume to remain the same or have minimal flow effects while increasing process gas flow over the parametric resonance monitors to increase the growth rate over the parametric resonance monitors. Thus, the exhaust system may include a configuration of fins and baffles to control gas flow rates. The fins, baffles, and other components of the exhaust system may further be formed of or coated with materials to increase thermal insulation of the process gases as they flow through the exhaust system. This allows for more predictable film growth over the parametric resonance monitors.

[0021] A software algorithm within the process chamber controller takes the growth rate measurements from the parametric resonance monitor and is able to calibrate other sensors within the process chamber and process conditions within the process chamber to increase the film thickness growth rate.

[0022] Figure 1 1 is a schematic diagram of a deposition chamber 100 according to an embodiment of the present application. 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 generates a cross flow of precursors across a top surface 150 of the substrate 102.

[0023] 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. 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 are disposed in the chamber body. As shown, a controller 120 is in communication with the deposition chamber 100, and the controller is used to control a process (such as those 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 cover 154. The plurality of upper lamps 141 form a part of an upper lamp module 155. The cover 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] A processing volume 136 is formed between the upper window 108 and the lower window 110. The processing volume 136 has a substrate support 106 disposed therein. The substrate support 106 includes a top surface on which the substrate 102 is disposed. The substrate support 106 is attached to the shaft 118. The shaft is connected to the 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 processing volume 136.

[0025] The substrate support 106 may include a lift pin hole 107 disposed therein. The lift pin hole 107 is sized to receive lift pins 132 for lifting the substrate 102 from the substrate support 106 before or after performing a deposition process. The lift pins 132 may rest on lift pin stops 134 when the substrate support 106 is lowered from the processing position to the transfer position.

[0026] The flow module 112 includes a plurality of process gas inlets 114, a plurality of purge gas inlets 164, and one or more exhaust outlets 116. The plurality of process gas inlets 114 and the plurality of purge gas inlets 164 are disposed on a side of the flow module 112 opposite to the one or more exhaust outlets 116. One or more flow guides are disposed below the plurality of process gas inlets 114 and the one or more exhaust outlets 116. The flow guides are disposed above the purge gas inlets 164. A liner layer 163 is disposed on an inner surface of the flow module 112 and protects the flow module 112 from the reaction gas used during the deposition process. The process gas inlets 114 and the purge gas inlets 164 are positioned so that the gas flows parallel to the top surface 150 of the substrate 102 disposed in the processing volume 136. The process gas inlet 114 is fluidly connected to the process gas source 151. The purge gas inlet 164 is fluidly connected to the purge gas source 162. The one or more exhaust outlets 116 are fluidly connected to the exhaust pump 157.

[0027] The one or more exhaust outlets 116 are further connected to an exhaust system or include an exhaust system. The exhaust system fluidly connects the one or more exhaust outlets 116 and an exhaust pump 157. The exhaust system as described herein includes one or more growth monitors 310 ( Figure 3A ) and is configured to assist in the controlled deposition of layers on the substrate 102.

[0028] Figure 2 The embodiment according to the present application is shown Figure 11. A cross-sectional plan view of a deposition chamber 100 is shown in FIG. 1. The deposition chamber 100 includes an injector 202 disposed opposite an 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 a flow module 112 or may be a part of the flow module 112. The exhaust system 178 is disposed on a side of the processing volume 136 opposite the injector 202. The exhaust system 178 is formed through, connected to, or is a part of a flow module.

[0029] The exhaust system 178 further includes at least one exhaust channel body 204a, 204b. The exhaust channel bodies 204a, 204b form an exhaust path for gases exiting the processing volume 126 before entering the exhaust collector 206. Figure 2 As shown, there is a first exhaust channel body 204a and a second exhaust channel body 204b. The first exhaust channel body 204a and the second exhaust channel body 204b are mirror images and may be similar in size and configuration. In other embodiments, there may be more or fewer exhaust channel bodies 204a, 204b. In some embodiments, there is only one exhaust channel body, so that the two exhaust channel bodies 204a, 204b are merged into a single body. In other embodiments, there may be three or more exhaust channel bodies, such as three exhaust channel bodies 204a, 204b. The size and configuration of the exhaust channel bodies 204a, 204b may be changed according to the size and operation of the deposition chamber 100.

[0030] The first exhaust channel body 204a and the second exhaust channel body 204b are both coupled to an exhaust collector 206 at an end of the exhaust channel body 204a, 204b opposite to the processing volume 136. The exhaust collector 206 is configured to collect exhaust gas from the first exhaust channel body 204a and the second exhaust channel body 204b. As the exhaust collector 206 extends away from the exhaust channel body 204a, 204b, the exhaust collector 206 narrows.

[0031] Figure 3A The embodiment according to the present application is shown Figure 1FIG. 1 is a cross-sectional plan view of an exhaust system 178 of a deposition chamber 100 of FIG. 1. The exhaust system 178 is configured to control exhaust flow exiting the processing volume 126 prior to flowing through one or more growth monitors 310. Increasing the flow over the growth monitors 310 relative to the flow at the inlet of the exhaust channel bodies 204a, 204b promotes film growth over the growth monitors 310. Thus, the width of each of the exhaust channel bodies 204a, 204b is narrowed from an inlet width W1 to an outlet width W2 to increase the flow. A fin array 314 and one or more baffles 304 are positioned within each of the exhaust channel bodies 204a, 204b to narrow the exhaust channel bodies 204a, 204b while reducing the effect of the narrowing on the flow path of the process gas through the processing volume 136.

[0032] As the process gas flows out of the process volume 136 and into the exhaust system 178, the process gas flows in a first flow path 318. The first flow path 318 is primarily parallel to the surface of the substrate 136 and the gas flowing out of the injector 202. The process gas flows into the exhaust system 178 via exhaust inlet openings 305a, 305b; the exhaust inlet openings 305a, 305b are disposed through each of the exhaust channel bodies 204a, 204b. Thus, the first exhaust inlet 305a is disposed through a first end of the first exhaust channel body 204a, and the second exhaust inlet 305b is disposed through a first end of the second exhaust channel body 204b. The exhaust inlet openings 305a, 205b are in fluid communication with exhaust plenums 312a, 312b. The exhaust plenums 312a, 312b are disposed within each of the exhaust channel bodies 204a, 204b. Thus, the first exhaust plenum 312a is disposed within the first exhaust passage body 204a, and the second exhaust plenum 312b is disposed within the second exhaust passage body 204b. The first exhaust inlet opening 305a is in fluid communication with the first exhaust plenum 312a, and the second exhaust inlet opening 305b is in fluid communication with the second exhaust plenum 312b.

[0033] Each exhaust inlet opening 305a, 305b has an inlet width W l The inlet width W1 is about 10 mm to about 210 mm, such as about 45 mm to about 210 mm, such as about 75 mm to about 175 mm, and such as about 100 mm to about 155 mm. The inlet width W1 is about 10 mm to about 210 mm, such as about 45 mm to about 210 mm, such as about 75 mm to about 175 mm, and such as about 100 mm to l It is therefore less than or equal to half the width of the processing volume 136 .

[0034] The exhaust outlet openings 308a, 308b are disposed on a side of the exhaust channel body 204a, 204b opposite to the exhaust inlet openings 305a, 305b. Therefore, the first exhaust outlet opening 308a is disposed on the second side of the first exhaust channel body 204a opposite to the first side, and is in fluid communication with the first exhaust plenum 312a. The second exhaust outlet opening 308b is disposed on the second side of the second exhaust channel body 204b opposite to the first side, and is in fluid communication with the second exhaust plenum 312b. The width of the exhaust outlet openings 308a, 308b is less than the width of the exhaust inlet openings 305a, 305b. The exhaust outlet openings 308a, 308b have an outlet width W2 of about 15mm to about 110mm, such as about 20mm to about 100mm, and such as about 20mm to about 40mm. The outlet width W2 less than the inlet width W1 enables a higher concentration of processing gas to flow through the growth monitor 310.

[0035] Entrance width W l The ratio of inlet width W1 to outlet width W2 is about 2: 1 to about 20: 1, such as about 3: 1 to about 10: 1 and such as about 4: 1 to about 8: 1. The ratio of inlet width W1 to outlet width W2 enables sufficient film growth on growth monitor 310 while reducing the effect of reduced outlet width W2 on back pressure and flow path through processing volume 136.

[0036] The process gas flowing through the deposition chamber 100 enters the exhaust channel body 204a, 204b through the exhaust inlet openings 305a, 305b, and before switching from the first flow path 318 to the second flow path 320, the gas chamber 312a, 312b is narrowed to an outlet width W2 adjacent to the outlet openings 308a, 308b by one or more baffles 304. The second flow path 320 guides the process gas to the centerline C of the exhaust system and to one side of the exhaust gas chamber 312a, 312b, such as the inner side of the exhaust gas chamber 312a, 312b. Once the process gas flows through the outlet openings 308a, 308b, the path of the process gas is changed to the third flow path 322. The third flow path 322 is a condensation flow path. The third flow path 322 is arranged to pass through the collector gas chamber 316. The collector gas chamber 316 is a gas chamber arranged in the exhaust collector 206.

[0037] The fin array 314 disposed within each exhaust channel body 204a, 204b is configured to maintain a first flow path 318 through at least a portion of the exhaust plenum 312a, 312b. The fin array 314 includes a plurality of fins 302 such that a first plurality of fins 302 is disposed within a first exhaust plenum 312a of the first exhaust channel body 204a. A second plurality of fins 302 is disposed within a second exhaust plenum 312b and a second exhaust channel body 204b. The fin array 314 is configured to maintain good flow control through the processing volume 136 and extends from a location adjacent to the exhaust inlet openings 305a, 305b.

[0038] The number of fins 302 in the fin array 314 can be at least four fins 302, such as at least 5 fins 302, such as 5 fins 302 to about 30 fins 302, such as 5 fins 302 to about 20 fins 302. The number of fins 302 helps to create a smaller gap between each adjacent fin 302 and helps to control the first flow path 318.

[0039] One or more growth monitors 310 are disposed within the fin arrays 314, such as between two adjacent fins 302. There may be two or more growth monitors 310 disposed within each fin array 314 of both the first exhaust channel body 204a and the second exhaust channel body 204b. The growth monitors 310 within the fin arrays 314 may help provide a measurement of growth rates at different locations on the substrate 102, as different growth monitors 310 may be associated with different locations on the substrate.

[0040] Each fin 302 within the fin array 314 is parallel to each other. The fins 302 extend in a direction parallel to the desired first flow path 318 and parallel to the direction of the gas flowing out of the injector 202. Other configurations of the fin array 314 are contemplated. In some embodiments, each fin 302 has a similar length. In other embodiments, each fin 302 does not necessarily have the same length, such that the fins 302 closer to the centerline C of the processing volume 136 and the exhaust system 178 are shorter than the fins 302 farther from the centerline C.

[0041] Once the process gas leaves the fin array 314, the process gas flows into the main portion 311 of the exhaust plenum 312a, 312b. The main portion 311 of the exhaust plenum 312a, 312b is open space, which can help reduce back pressure (if the fin array 314 extends all the way to the baffle 304, the back pressure will increase). In some embodiments, there is a gap of at least 5 mm between the end of the fin array 314 and the closest portion of the baffle 304, such as a gap of about 5 mm to about 40 mm.

[0042] The baffle 304 extends from an outer surface 328 of each of the exhaust passage bodies 204a, 204b to an inner surface 330 of each of the exhaust passage bodies 204a, 204b. The outer surface 328 is the inner surface of the exhaust plenum 312a, 312b farthest from the centerline C. The inner surface 330 is the inner surface of the exhaust plenum 312a, 312b closest to the centerline C. Thus, the baffle 304 within the first exhaust passage body 204a extends from the outer surface 318 of the first exhaust plenum 312a toward the inner surface 330 of the first exhaust passage plenum 312a or the centerline C of the exhaust system 178. The baffle 304 within the second exhaust passage body 204b extends from the outer surface 318 of the second exhaust plenum 312b to the inner surface 330 of the second exhaust passage plenum 312b or the centerline C of the exhaust system 178.

[0043] The baffle 304 extends at an angle φ relative to the outer surface 328 of each of the exhaust plenums 312a, 312b. The angle φ is an internal angle facing the fin array 314. The angle φ is an obtuse angle, such that the angle φ is greater than about 90 degrees, such as about 100 degrees to about 170 degrees, such as about 100 degrees to about 160 degrees, and such as about 110 degrees to about 145 degrees. Setting the angle of the baffle 304 helps control the restriction rate of the exhaust plenums 312a, 312b. The baffle 304 is set at an angle other than 0 degrees or 90 degrees relative to the direction of the fin 302, such as between about 10 degrees and about 80 degrees relative to the direction of the fin 302. The baffle 304 extends over 50% of the width of each of the exhaust plenums 312a, 312b, such as over 60% of the width of each of the exhaust plenums 312a, 312b, and such as over 70% of the width of each of the exhaust plenums 312a, 312b. In some embodiments, the baffle 304 has a radius of curvature defined as a radius from the center of the processing volume 136 of the deposition chamber 100 to the gas guide surface 332. In some embodiments, the radius of curvature varies on the gas guide surface 332 so that a portion of the gas guide surface 332 close to the inner surface 330 has a smaller radius of curvature. The radius of curvature of the gas guide surface 332 may also be a radius other than the radius of the center of the processing volume 136. Each baffle 304 has a gas guide surface 332. The gas guide surface 332 is the surface of the baffle 304 that faces the main portion 311 of the exhaust plenum 312a, 312b and the fin array 314.

[0044] The baffle 304 may have a curved gas guiding surface 332, a straight gas guiding surface 332, or a multi-faceted gas guiding surface 332. The gas guiding surface 332 may be Figure 3A332, but in some embodiments, the gas directing surface 332 may be curved so that the gas directing surface 332 follows the circumference of a circle, ellipse, hyperbola, or parabola. The curved surface may allow for better gas flow control and reduce eddies or turbulence within the gas flow path. The curvature of the gas directing surface 332 may vary depending on the size of the deposition chamber 100 and the size of the exhaust system 178.

[0045] The exhaust outlet openings 308a, 308b are disposed between the innermost portion of each baffle 304 and the inner surface 330 of each of the exhaust plenums 312a, 312b. The first exhaust outlet opening 308a is disposed within the first exhaust plenum 312a and connects the first exhaust plenum 312a to the collector plenum 316. The second exhaust outlet opening 308b is disposed within the second exhaust plenum 312b and connects the second exhaust plenum 312b to the collector plenum 316.

[0046] One or more growth monitors 310 are located within the exhaust outlet openings 308a, 308b, or just downstream of the exhaust outlet openings 308a, 308b. A first growth monitor 310 is disposed within the first exhaust outlet opening 308a, or just downstream of the exhaust outlet opening 308a. A second growth monitor 310 is disposed within the second exhaust outlet opening 308b, or just downstream of the second exhaust outlet opening 308b. A growth monitor 310 disposed just downstream of the exhaust outlet openings 308a, 308b is defined as a growth monitor 310 disposed within 10 mm of the exhaust outlet openings 308a, 308b and away from the fin array 314.

[0047] The baffles 304 narrow the passage of exhaust gas through the exhaust plenums 312a, 312b, thereby increasing the density or concentration of the exhaust gas flowing through the growth monitor 310. The growth monitor 310 is disposed on the top surface 326 or the bottom surface 327 ( Figure 3B ) such that growth monitor 310 does not block third flow path 322, but is aligned with third flow path 322. Growth monitor 310 is at least partially located within collector plenum 316.

[0048] The exhaust gas is discharged through the duct opening 306 ( Figure 3B) before being removed from the exhaust collector 206, the exhaust passes through the growth monitor 310 and enters the collector plenum 316. The width of the collector plenum 316 adjacent to the outlet openings 308a, 308b is wider than the outlet openings 308a, 308b, such that the width of the collector plenum 316 adjacent to each outlet opening 308a, 308b is similar to the inlet width W1, and the total width of the collector plenum 316 is similar to or greater than twice the inlet width W1.

[0049] The conduit opening 306 is disposed at a portion of the collector air chamber 316 opposite the outlet openings 308a, 308b. The conduit opening 306 is configured to enable exhaust gas within the exhaust collector 206 to be discharged to the exhaust pump 157 via the exhaust conduit 323. Another growth monitor 310 is adjacent to the conduit opening 306 and within the collector air chamber 316. The monitor 310 adjacent to the conduit opening 306 is disposed on the back side wall 321 ( Figure 3B ). In some embodiments, growth monitor 310 can be disposed directly above duct opening 306 or within duct opening 306 , such as within an upper portion of exhaust duct 323 .

[0050] At least the fins 302 and the baffles 304 may be formed of or coated with a material having a high thermal conductivity; a material having a high thermal conductivity, such as a material having a thermal conductivity greater than about 100 W / m·°K (e.g., greater than about 150 W / m·°K and greater than about 175 W / m·°K). The material of the fins 302 is selected to reduce contamination of the deposition chamber 100 while also maintaining the temperature of the exhaust gas flowing through the exhaust plenums 312a, 312b before flowing through the growth monitor 310. In some embodiments, at least a portion of the walls forming the exhaust plenums 312a, 312b are coated with a material having a high thermal conductivity similar to the fins 302 and the baffles 304. The interior of the exhaust collector 206 may be similarly coated with a material having a high thermal conductivity. The material having a high thermal conductivity may be silicon carbide (SiC). Other suitable materials having a high thermal conductivity are contemplated. In some embodiments, the fins 302 and the baffles 304 are formed of graphite and coated with silicon carbide. The high thermal conductivity material conducts heat away from the processing volume 136 and reduces the cooling rate of the exhaust gas flowing through the exhaust plenums 312a, 312b. Keeping the exhaust gas heated before it flows through the growth monitor 310 enables a more consistent film to be formed on the growth monitor 310 to provide a more accurate estimate of the film growth rate within the processing chamber.

[0051] Figure 3B The embodiment according to the present application is shown Figure 1 FIG. 1 is a cross-sectional side view of the exhaust system 178 of the deposition chamber 100. Figure 3BAs shown, the exhaust plenums 312a, 312b of the exhaust system 178 extend through at least a portion of the flow module 112 such that the exhaust plenums 312a, 312b extend through the flow module 112. The fins 302 are disposed adjacent the processing volume 136.

[0052] The fins 302 and baffles 304 extend the entire height of the exhaust plenums 312a, 312b such that the fins 302 and baffles 304 extend between the top surface 326 and the bottom surface 327 of the exhaust plenums 312a, 312b. A growth monitor inside the fin array 314 is disposed on the top surface 326.

[0053] The exhaust collector 206 is connected to the rear end of the exhaust system 178. The exhaust collector 206 includes a top surface 328, a bottom surface 327, and a rear sidewall 324. A growth monitor 310 located just downstream of the exhaust outlet openings 308a, 308b is positioned on the top surface 328 of the collector plenum 316 within the exhaust collector 206. Another growth monitor 310 is disposed on the rear sidewall 321 of the collector plenum 316. The positioning of the growth monitors 310 enables accurate film growth rate measurements to be achieved by each of the growth monitors 310. The measurements from each of the growth monitors 310 can be mapped to view growth rate differences at different locations of the substrate 102.

[0054] A conduit opening 306 is disposed through a bottom surface 327 of the collector plenum 316 and opens into an exhaust conduit 323. The exhaust conduit 323 extends downwardly from the conduit opening 306 and is fluidly connected to the exhaust pump 157. Another growth monitor 310 may be positioned on the inner wall of the exhaust conduit 323 downstream of the growth monitor 310 on the rear sidewall 321 of the collection chamber 316.

[0055] In some embodiments, more or fewer growth monitors 310 may be used within the exhaust system 178. In some embodiments, only the growth monitors 310 adjacent to the exhaust outlet openings 308a, 308b are disposed within the exhaust system 178. In other embodiments, the growth monitors 310 adjacent to the exhaust outlet openings 308a, 308b may be a single growth monitor 310. In other embodiments, growth monitors 310 adjacent to the exhaust outlet openings 308a, 308b and growth monitors 310 on the rear sidewall 321 of the collector plenum 316 are utilized.

[0056] Figure 4A and Figure 4B The embodiment according to the present application is shown Figure 1Growth monitor 310 within deposition chamber 100. Growth monitor 310 is a parametric resonance sensor including shuttle block 402, electrostatic actuator 404, amplitude and / or velocity sensor 406, multiple anchors 408, and multiple beams 410. Shuttle block 402 is one or more of a silicon-containing material, bulk titanium, and electroplated nickel.

[0057] The shuttle block 402 further includes a first finger group 420 and a third finger group 424. The electrostatic actuator 404 further includes a second finger group 422. In one embodiment, the amplitude and / or velocity sensor 406 is a capacitive sensor. The capacitive sensor 406 further includes a fourth finger group 426. The first to fourth finger groups 420, 422, 424, and 426 may be accelerometers, gyroscopes, or other similar systems. The growth monitor 310 is further coupled to a potential source 412 capable of applying a voltage to the electrostatic actuator 404. The potential source 412 is further configured to act as (or may include) a ground for connecting to one of the plurality of anchors 408. The plurality of beams 410 are configured to couple the shuttle block 402 to the anchor 408 so that the anchor 408 secures the shuttle block 402 to the exhaust collector 206. In one example, the amplitude and / or velocity sensor 406 may additionally or alternatively be a frequency sensor.

[0058] In operation, the first finger group 420 is in a spaced relationship with the second finger group 422, and the third finger group 424 is in a spaced relationship with the fourth finger group 426. Figure 4A In one embodiment shown, the spaced relationship of the plurality of finger groups is a comb configuration of interdigitated fingers; that is, the first finger group 420 is interdigitated with the second finger group 422, and the third finger group 424 is interdigitated with the fourth finger group 426. In yet another embodiment, the spaced relationship is a secondary comb finger configuration in which the interdigitated fingers are bent. When the potential source 412 applies a bias to the electrostatic actuator 404, the electrostatic actuator 404 is configured to actuate the shuttle block 402 at an actuation frequency. The input bias actuates the shuttle block 402 in a frequency range close to the parametric resonant instability frequency. Applying the bias to the first finger group 420 and the second finger group 424 causes the normal forces on both sides of each finger in the finger group to cancel. However, the lateral force actuates the first finger group 420 parallel to the second finger group 422, thereby actuating the shuttle block 402. In one embodiment, the actuation is translational. In another embodiment, the actuation is rotational. In Figure 4BIn another embodiment shown, the spaced apart relationship of the plurality of finger groups is a non-interdigitated comb finger configuration. The shuttle block 402 is anchored in place by the anchor 408 via a plurality of beams 410. The plurality of beams 410 are configured to resist the actuation of the shuttle block 402. When the shuttle block 402 moves relative to the electrostatic actuator 404 due to the force between the first finger group 420 and the second finger group 422, the plurality of beams 410 act as a spring to move the shuttle block 402 back to its original position. The third finger group 424 is configured to move parallel to the fourth finger group 426 due to the actuation of the shuttle block 402. The capacitive sensor is configured to measure the change in the parametric resonance instability frequency by measuring the actuation amplitude and / or the speed of the shuttle block 402. The frequency value at which the amplitude increases significantly at the unstable frequency is precisely known. As the mass of the shuttle block 402 increases, the transition frequency changes. As further described below, tracking the transition frequency allows the thickness of the material deposited on the growth monitor 310 to be measured.

[0059] The parametric resonance sensor measures the frequency shift at the resonance stability boundary to monitor the mass change on the shuttle mass 402. The amplitude and / or velocity transitions at the resonance stability boundary are very sharp, so that small frequency changes are easily detected with higher resolution of the frequency shift. The benefit of the parametric resonance sensor is that the sharpness of the boundary is independent of the quality factor (Q). Therefore, very small mass changes can be detected in high pressure environments and at atmospheric pressure.

[0060] In contrast, simple harmonic resonance-based mass sensing devices, such as quartz crystal microbalances (QCMs), are limited by their ability to detect small frequency changes described by the quality factor (Q). The minimum detectable mass change using SHR is proportional to the minimum detectable frequency change, which is inversely proportional to the Q factor. Therefore, in epitaxial mass deposition monitoring applications where typical pressures range from 5 Torr to 760 Torr, the minimum detectable mass change is significantly higher. This limits the range of processes that QCM-based sensing can be used to monitor. However, the parametric resonance sensor of the present application has a much wider process window than simple harmonic resonance-based sensing devices, enabling more accurate monitoring and detection (particularly in high pressure and / or epitaxial deposition processes).

[0061] As the exhaust flows through the exhaust system 178, unreacted precursor gases present in the reactant byproducts are deposited onto the growth monitor 310. The shuttle block 402 is actuated using a voltage applied by a potential source 412. A periodic sweep over a small range of frequencies is performed near the region of parameter instability. When the region of instability is crossed, the vibration amplitude changes suddenly. In one embodiment, the capacitance sensor measures the vibration amplitude when the capacitance between the shuttle block 402 and the capacitance sensor changes due to the positional offset of the third finger group 424 relative to the fourth finger group 426. The frequency at which this occurs is recorded and compared to the value of the last frequency sweep. The change in frequency is related to the change in mass. Due to the previous calibration, the change in mass due to condensation on the shuttle block 402 is related to the thickness deposited on the substrate 102. This enables in-situ and real-time measurement of deposition on the substrate 102.

[0062] In another embodiment, the amplitude and / or velocity sensor 406 is a laser Doppler vibrometer. The laser Doppler vibrometer is configured to measure light reflected from the shuttle block to characterize the actuation amplitude and / or velocity of the shuttle block 402. The vibration amplitude is measured using a laser Doppler vibrometer. In one embodiment, the laser Doppler vibrometer amplitude and / or velocity sensor has a 45 degree mirror built into it. The mirror can be cut with a focused ion beam after device fabrication. The laser light is aimed at the mirror and is reflected onto the shuttle block 402. The reflected light from the shuttle block 402 is measured to characterize the actuation amplitude and / or velocity of the shuttle block 402. As the mass of the shuttle block 402 increases due to the deposition of exhaust gas, the measured value of the reflected light changes. The laser Doppler vibrometer indirectly measures the change in the parametric resonant frequency by measuring the amplitude and / or velocity and recording the frequency at which the transition to large amplitude oscillation begins. Tracking this change in the parametric resonant frequency over time as the mass of the shuttle block 402 continues to increase allows the thickness of the material deposited on the growth monitor 310 to be determined. The mass variation due to condensation on the shuttle block is related to the thickness deposited on the substrate 102 due to the previous calibration.

[0063] The growth monitor 310 is configured to be positioned within the deposition chamber 100, thus taking into account the reactive process chemistry within the exhaust system 178. The protective coating, the material of the anchor 408, the plurality of beams 410, and the shuttle block 402 affect the reactivity of the growth monitor 310 with the process chemistry within the deposition chamber 100. Therefore, a material composition is selected that reduces the reactivity of the growth monitor 310 with the process chemistry within the deposition chamber 100 while still enabling accurate film thickness measurements to be made on the growth monitor 310.

[0064] The protective coating is formed of one of aluminum oxide (Al2O3) or silicon oxide such as silicon dioxide (SiO2). The protective coating is formed of a material that does not degrade when exposed to epitaxial deposition processing conditions or processing gases. The protective coating may be a cover lens, or may be a coating applied to shuttle block 402. The protective coating has a thickness of less than about 10 μm, such as about 1 nm to about 10 nm and such as about 1 nm to about 5 nm. The small thickness can protect growth monitor 310 without significantly damping the actuation of shuttle block 402.

[0065] Figure 5 The embodiment according to the present application is shown Figure 1 Schematic diagram 500 of control within a deposition chamber 100. The controller 120 is configured to receive data from each growth monitor 310 or as input of sensor readings 502. The controller 120 is equipped with or communicates with a system model 506 of the deposition chamber 100. The system model 506 includes a heating model and an airflow module. The system model 506 is a program configured to estimate the airflow and heating within the deposition chamber 100 throughout the deposition process. The controller 120 is further configured to store the readings and calculate 504.

[0066] The readings and calculations 504 include the previous sensor readings 502 and any other previous sensor readings within the deposition chamber 100. The readings and calculations 504 further include calculated values ​​stored after the controller 120 measures the sensor readings 502 and runs the system model 506. Therefore, the controller 120 is configured to retrieve the stored readings and calculations 504 and save the readings and calculations 504 for future use. Keeping the previous readings and calculations enables the controller 120 to adjust the system model 506 over time to reflect a more accurate version of the deposition chamber 100.

[0067] In the embodiments described herein, the controller 120 includes a programmable central processing unit (CPU) operating in conjunction with a memory and mass storage device, an input control unit, and a display unit (not shown). The controller 120 monitors the flow of precursors, process gases, and purge gases. Support circuits are coupled to the CPU to support the processor in a conventional manner. In some embodiments, the controller 120 includes multiple controllers 120 so that the stored readings and calculations 504 and the system model 506 are stored in a controller separate from the controller 120 that operates the deposition chamber 100. In other embodiments, all system models 506 and stored readings and calculations 504 are stored in the controller 120.

[0068] The controller 120 is configured to control heating and gas flow through the deposition chamber 100 by controlling aspects of the lamp and gas flow control 508. The lamp and gas flow control 508 includes the upper lamp 141, the lower lamp 143, the process gas source 151, the purge gas source 162, and the exhaust pump 157. The controller 120 may also control the motion assembly 121 within the deposition chamber 100.

[0069] The controller 120 is configured to adjust the output of each of the lamp and gas flow control 508 based on the sensor readings 502, the system model 506, and the stored readings and calculations 504. The controller 120 includes embedded software and compensation algorithms for calibrating the frequency shift of the growth monitor 310 to the film thickness on the substrate 102. The film thickness on the substrate 102 can be measured when the substrate 102 leaves the deposition chamber or between processing operations to provide a reference for the film thickness growth rate measured using the growth monitor 310. The controller 120 can include a machine learning algorithm and can use regression or clustering techniques. The algorithm is an unsupervised algorithm or a supervised algorithm.

[0070] Figure 6 The embodiment according to the present application is shown in Figure 1 The method 600 is a method of adjusting processing conditions in a deposition chamber 100 of the present invention. The method 600 utilizes the growth monitor 310 in the deposition chamber 100 and the controller 120 described herein to improve film thickness uniformity and characteristics across the substrate 102.

[0071] During method 600, a first substrate is processed in a processing chamber during operation 602. The first substrate may be substrate 102, and the processing chamber is deposition chamber 100. Processing the first substrate during operation 602 includes performing a deposition process, such as an epitaxial deposition process, on the first substrate. The deposition process grows a film on the first substrate and includes heating the substrate using upper lamps 141 and lower lamps 143. Gas flows from process gas inlet 114 and purge gas inlet 164 through processing volume 136 and is then removed via exhaust outlet 116.

[0072] While the first substrate is being processed within the processing chamber, the growth monitor 310 is used to measure film thickness growth on the monitor during another operation 604. The measurement of film thickness growth on the growth monitor 310 is performed as a rolling operation. FIG. 3A to FIG. 3BThe described combination of growth monitor 310 receives input. The input is used to estimate film growth on the first substrate. Once processing of the first substrate is completed within the processing chamber, the film thickness can be measured during another operation 606 using one or more other non-contact sensors within the processing chamber or in an adjacent chamber. Film growth measurements on the first substrate are performed in a non-destructive manner (such as by using one or more non-contact sensors) during operation 606. The non-contact sensor can be a laser thickness gauge and can make multiple discrete measurements across the surface of the first substrate or can scan the length of the first substrate.

[0073] The non-contact sensor used during operation 606 is not necessarily used for film thickness measurement during substrate processing because process gases and radiation from the heating source can interfere with the sensor readings and reduce the reading sensitivity and accuracy. The growth monitor 310 is thus able to adjust process conditions, such as heating and gas flow, while processing the first substrate. Measurements using the non-contact sensor can be used to update or confirm the correlation between film formation on the growth monitor(s) 310 and film formation on the substrate. Therefore, measurements using the non-contact sensor are optional and can be omitted.

[0074] The measurement of the film growth on the first substrate enables the calculation of the growth rate on the first substrate during another operation 608. Calculating the growth rate on the first substrate during operation 608 verifies the accuracy of the model used in the controller and enables the processing chamber model to be adjusted during another operation 610 to achieve a predetermined film growth on the substrate during processing. Adjusting the processing chamber model during operation 610 enables better use of the growth monitor 310 for a particular process. Once the model has been adjusted, processing of another substrate (such as a second substrate) is performed and operations 602 to 610 are repeated. Operation 602 can be looped to continuously adjust the accuracy of the processing chamber model 610 and improve the film thickness growth results. When preventive maintenance is performed on the processing chamber, the processing chamber model can be reset or adjusted, and the method 600 starts again. Therefore, the film thickness is a result of continuous improvement between each substrate. This further achieves accurate film thickness and overcomes changes in processing chamber characteristics caused by film accumulation on surfaces within the processing volume and lamp aging.

[0075] Figure 7A method 700 for using the growth monitor 310 according to an embodiment is described. At operation 702, the shuttle block 402 is actuated by an electrostatic force from an electrostatic actuator. At operation 704, a range of frequencies is swept near the parametric resonance instability boundary of the shuttle block 402. At operation 706, exhaust gas is deposited on the shuttle block 402, causing the vibration amplitude of the shuttle block 402 to suddenly change. The frequency value is recorded by the controller 120. At operation 708, the current value of the instability frequency is compared to the previous value of the instability frequency. The difference in value corresponds to the change in mass of the shuttle block 402 caused by the exhaust gas deposition. The correspondence between the instability frequencies (and the changes between the instability frequencies) related to mass can be determined empirically and stored in a data table accessible by the controller. At operation 710, the controller 120 outputs the thickness value to the user. The thickness value is calculated using a previous calibration; the previous calibration correlates the change in mass of the shuttle block 402 to the increase in thickness on the substrate 102. At operation 712 , a frequency range near the parametric resonance boundary is periodically swept to continuously monitor thickness changes across the shuttle block 402 .

[0076] While the foregoing is directed to embodiments of the present application, other and further embodiments of the present application may be devised without departing from the basic scope thereof, and the scope of the present application is determined by the claims that follow.

Claims

1. An exhaust system for substrate processing, comprising: a first exhaust air chamber; a first exhaust inlet opening fluidly connected to the first exhaust plenum; a first plurality of fins disposed within the first exhaust plenum adjacent to the first exhaust inlet opening; a first exhaust outlet opening fluidly connected to the first exhaust plenum; a first baffle disposed adjacent to the first exhaust outlet opening and configured to narrow a width of the first exhaust plenum; and At least one growth monitor is disposed downstream of the first baffle and is configured to measure a thickness of material deposited on the growth monitor, wherein the at least one growth monitor is a parametric resonance sensor.

2. The exhaust system of claim 1, wherein the parametric resonance sensor comprises: Shuttle block; an electrostatic actuator configured to actuate the shuttle mass at an actuation frequency; an amplitude and / or velocity sensor configured to measure changes in the actuation amplitude and / or velocity of the shuttle block; Multiple anchors; and A plurality of beams, wherein the plurality of beams are configured to couple the plurality of anchors to the shuttle block, and wherein the plurality of beams resist actuation of the shuttle block.

3. The exhaust system of claim 2, wherein the shuttle block comprises one or more of a silicon-containing material, bulk titanium, and electroplated nickel.

4. The exhaust system of claim 2, wherein the shuttle block further comprises a first set of fingers, and wherein the electrostatic actuator further comprises a second set of fingers, the first set of fingers being configured to actuate in parallel with the second set of fingers.

5. The exhaust system of claim 4, wherein the shuttle block further comprises a third set of fingers, and wherein the amplitude and / or velocity sensor is a capacitive sensor, the capacitive sensor further comprising a fourth set of fingers, wherein the third set of fingers is configured to move parallel to the fourth set of fingers due to actuation of the shuttle block.

6. The exhaust system of claim 5, wherein the capacitive sensor measures a change in a parametric resonant frequency as the mass of the shuttle block increases to determine the thickness of the material deposited on the growth monitor.

7. The exhaust system of claim 4, wherein the amplitude and / or velocity sensor is a laser Doppler vibrometer configured to measure light reflected from the shuttle mass to track the changes in the resonant frequency of the shuttle mass.

8. The exhaust system of claim 7, wherein the laser Doppler vibrometer measures changes in the actuation amplitude and / or velocity as the mass of the shuttle block increases to determine the thickness of the material deposited on the growth monitor.

9. A processing system suitable for processing a semiconductor substrate, comprising: a chamber body forming a processing volume; a substrate support disposed within the processing volume of the chamber body; an upper window, the upper window being disposed above the substrate support; a lower window disposed below the substrate support, wherein the upper window and the lower window further define the processing volume; an injector disposed through a side of the chamber body and configured to introduce a process gas into the process volume; and An exhaust system is disposed through a second side of the chamber body opposite the injector, and the exhaust system includes at least one growth monitor configured to measure a thickness of material deposited on the growth monitor, wherein the growth monitor is a parametric resonance sensor.

10. The processing system of claim 9, wherein the parametric resonance sensor comprises: Shuttle block; an electrostatic actuator configured to actuate the shuttle mass at an actuation frequency; an amplitude and / or velocity sensor configured to measure changes in actuation of the shuttle block; a plurality of anchors configured to be coupled to the exhaust system; and A plurality of beams, wherein the plurality of beams are configured to couple the plurality of anchors to the shuttle block, and wherein the plurality of beams resist the actuation of the shuttle block.

11. The processing system of claim 10, wherein the shuttle block comprises one or more of a silicon-containing material, bulk titanium, and electroplated nickel.

12. The processing system of claim 10, wherein the shuttle block further comprises a protective coating, wherein the protective coating is one of aluminum oxide or silicon dioxide.

13. The processing system of claim 9, wherein the at least one growth monitor communicates with a controller, the controller being configured to determine a growth rate on the growth monitor and to adjust at least one of a process gas flow rate, a heating energy level, or an exhaust flow rate in response to the determined growth rate.

14. The processing system of claim 10, further comprising a controller, wherein the controller compares the growth rate measured on the growth monitor, a chamber thermal model, a chamber flow model, and previous monitor measurements to determine an adjustment to at least one of a process gas flow rate, a heating energy level, or an exhaust flow rate.

15. A controller for a processing system storing instructions which, when executed by a processor, cause the system to: processing the substrate within a processing chamber by flowing a process gas from a process gas inlet through a processing volume, depositing the gas on the substrate, and exhausting the process gas via an exhaust system, wherein the exhaust system further comprises a growth monitor comprising a parametric resonance sensor; depositing the process gas onto the growth monitor; measuring film growth on the growth monitor; calculating a film growth rate on the substrate; and Adjust processing chamber parameters.

16. A controller as claimed in claim 15, wherein the controller further causes actuation of the shuttle mass relative to an amplitude and / or velocity sensor.

17. The controller of claim 16, further causing the system to sweep a frequency range near a parametric resonant instability boundary of the shuttle mass at first and second time intervals to determine a parametric resonant instability frequency of the shuttle mass.

18. The controller of claim 17, further causing the system to compare the value of the parameter instability frequency of the shuttle block at a first time interval with the value of the parameter instability frequency of the shuttle block at a second time interval to output film growth on the substrate using the processing chamber parameters.

19. The controller of claim 18, wherein the controller adjusts at least one of a process gas flow rate, a heating energy level, or an exhaust flow rate in response to the calculated film growth rate on the substrate.

20. A controller as described in claim 19, wherein the controller compares the growth rate measured on the growth monitor, the chamber thermal model, the chamber flow model, and previous monitor measurements to determine adjustments to at least one of the process gas flow rate, the heating energy level, or the exhaust flow rate.

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