In situ EPI growth rate control of crystal thickness microbalancing sensors

Abstract

Disclosed herein is a method and apparatus for processing semiconductor substrates. The apparatus includes one or more growth monitors disposed in an exhaust system of a deposition chamber. The growth monitors are quartz film thickness monitors and are configured to measure a film thickness grown on the growth monitor while a substrate is being processed in the deposition chamber. The growth monitors are connected to a controller that adjusts settings of heating and gas flow devices during processing operations. Measurements from the growth monitors and other sensors in the deposition chamber are used to adjust a process chamber model of the deposition chamber as a substrate is being processed therein.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE

[0002] Embodiments of the present disclosure relate generally to an apparatus and method for manufacturing semiconductor devices. More particularly, the apparatus disclosed herein relates to an exhaust assembly and a growth rate sensor in a semiconductor processing chamber. Methods of use thereof are also disclosed. [Background technology]

[0002] Semiconductor substrates are processed for a wide variety of applications, including the fabrication of integrated devices and microdevices. During processing, the substrate is placed on a susceptor in a processing chamber. The susceptor is supported by a support shaft that is rotatable about a central axis. To uniformly heat the substrate within close tolerances, precise control of the heating source is preferred. The temperature of the substrate can affect the uniformity of the material deposited on the substrate.

[0003] The ability to accurately control substrate temperature in a processing chamber has a significant impact on throughput and production yield. Conventional processing chambers have difficulty meeting the temperature control standards required for manufacturing next generation devices while meeting the ever increasing demand for higher production yields and faster throughput. Processing gases are flowed throughout the processing volume in the processing chamber. Processing gases are flowed parallel to the substrate surface from one side of the processing chamber to the other side of the processing chamber. Heating and gas flow in the processing chamber can be adjusted to improve film deposition rates across the substrate. Current sensors in the processing chamber have limited resolution, and adding additional sensors increases processing chamber downtime and increases cost of ownership. Substrates processed between calibration and measurement operations also suffer from less accurate deposition rates due to changes in chamber conditions. Current sensors in the processing chamber include pyrometers, but pyrometers have limited resolution. Downstream pressure sensors cannot provide adequate partial pressure estimates across other parts of the processing chamber.

[0004] Therefore, there is a need for improved pumping systems and growth rate monitoring. Summary of the Invention

[0005] The present disclosure generally relates to a processing chamber for semiconductor processing. In one embodiment, an exhaust passage body for substrate processing is described. The exhaust passage body includes a first exhaust plenum, a first exhaust inlet opening, a first plurality of fins, a first exhaust outlet opening, a first baffle plate, and at least one growth monitor. The first exhaust plenum is formed through a first end of the exhaust passage body and is fluidly connected to the first exhaust plenum. The first plurality of fins are disposed adjacent to the first exhaust inlet opening in the first exhaust plenum. The first exhaust outlet opening is formed through a second end of the exhaust passage body and is fluidly connected to the first exhaust plenum. The first baffle plate is disposed adjacent to the first exhaust outlet opening and is configured to narrow the width of the first exhaust plenum. The at least one growth monitor is disposed downstream of the first baffle plate and configured to measure a thickness of a material disposed on the growth monitor.

[0006] In another embodiment, an exhaust system for substrate processing is described. The exhaust system includes an exhaust passage body, an exhaust plenum, an exhaust inlet opening, a plurality of fins, an exhaust outlet opening, at least one baffle plate, and at least one growth monitor. The exhaust inlet opening is formed through a first end of the exhaust passage body and has an inlet width. The exhaust inlet opening is configured to fluidly connect the exhaust plenum and a process volume. The plurality of fins are disposed adjacent to the exhaust inlet opening in the exhaust plenum. The exhaust outlet opening is formed through a second end of the exhaust passage body and is fluidly connected to the exhaust plenum. The at least one baffle plate is disposed adjacent to the exhaust outlet opening and configured to narrow the width of the exhaust plenum to an outlet width that is narrower than the inlet width. The at least one growth monitor is disposed downstream of the baffle plate and configured to measure a thickness of a material disposed on the growth monitor. An exhaust collector is coupled to the exhaust passage body at an exhaust outlet.

[0007] In another embodiment, a processing system for substrate processing is described. The processing system includes a chamber body forming a process volume, a substrate support disposed within the process volume of the chamber body, an upper window disposed above the substrate support, and a lower window disposed below the substrate support. Each of the upper window and the lower window further defines a process volume. An injector is disposed through one side of the chamber body and configured to introduce a process gas into the process volume. An exhaust system is disposed through a second side of the chamber body opposite the injector. The exhaust system includes an exhaust passage body, an exhaust plenum disposed through the exhaust passage body, an exhaust inlet opening, a plurality of fins, an exhaust outlet opening, at least one baffle plate, and at least one growth monitor. The exhaust inlet opening is formed through a first end of the exhaust passage body. The exhaust inlet opening is configured to fluidly connect the exhaust plenum and the process volume. The plurality of fins are disposed within the exhaust plenum. The exhaust outlet opening is formed through a second end of the exhaust passage body and fluidly connected to the exhaust plenum. At least one baffle plate is disposed downstream of the plurality of fins and configured to reduce a width of the exhaust plenum to an exit width that is less than the entrance width, and at least one growth monitor is disposed downstream of the baffle plate and configured to measure a thickness of a material disposed on the growth monitor.

[0008] So that the above-mentioned features of the present disclosure can be understood in detail, a more particular description of the present disclosure, briefly summarized above, can be had by reference to embodiments, some of which are illustrated in the accompanying drawings, in which it is noted, however, that the accompanying drawings depict only exemplary embodiments and therefore should not be considered as limiting the scope of the present disclosure, which may admit of other equally effective embodiments. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a deposition chamber according to an embodiment of the present disclosure; [Diagram 2]2 is a cross-sectional plan view of the deposition chamber of FIG. 1 according to an embodiment of the present disclosure. [Figure 3A] 2 is a cross-sectional plan view of an exhaust system of the deposition chamber of FIG. 1 according to an embodiment of the present disclosure. [Figure 3B] 2 is a cross-sectional side view of an exhaust system of the deposition chamber of FIG. 1 according to an embodiment of the present disclosure. [Figure 4] A growth monitor for use in the deposition chamber of FIG. 1 according to an embodiment of the present disclosure. [Diagram 5] FIG. 2 is a control schematic for use in the deposition chamber of FIG. 1 according to an embodiment of the present disclosure. [Figure 6] A method for adjusting process conditions in the deposition chamber of FIG. 1 according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] To facilitate understanding, wherever possible, like reference numerals are used to designate like elements common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0011] The present disclosure relates to an exhaust assembly and a growth rate sensor in a semiconductor processing chamber. The growth rate sensor is a quartz crystal film thickness monitor that allows for a measurement of film thickness on the growth rate sensor. The film thickness on the growth rate sensor corresponds to a growth rate on a substrate in the processing chamber. The thickness measurements can then be utilized to adjust one or more process controls in the throughput of the processing chamber to improve film growth across the substrate.

[0012] A quartz crystal monitor without additional protection may react with the chemicals of the epitaxial deposition process. Thus, the quartz crystal monitor described herein is configured to reduce reactions with the chemicals of the epitaxial deposition process that may adversely affect either the sensor performance, the sensor life, or the process conditions in the processing chamber. Coating the quartz crystal of the quartz crystal monitor reduces the reaction of the process chemicals with the quartz crystal. Similarly, the use of gold-containing contacts in the quartz crystal monitor reduces chemical interaction between the metal of the sensor head and the process chemicals.

[0013] The location and number of the quartz monitors provide improved sensitivity and sensor life cycle. The configuration of the exhaust system around the quartz monitor allows for increased process gas flow across the quartz monitor to improve growth rates on the quartz monitor while maintaining the same gas flow rate in the process volume or with minimal impact on the flow rate. Thus, the exhaust system may include a fin and baffle configuration to control the gas flow rate. The fins, baffles, and other components of the exhaust system may further be formed or coated with materials to enhance thermal retention of the process gas as it flows through the exhaust system. This allows for more predictable and enhanced film growth on the quartz monitor.

[0014] A software algorithm in the process chamber controller obtains the growth rate measurement from the quartz crystal monitor and enables calibration of other sensors in the process chamber and process conditions in the process chamber to improve the film thickness growth rate.

[0015] 1 is a schematic diagram 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 utilized to grow an epitaxial film on a substrate, such as a substrate 102. The deposition chamber 100 generates a cross-flow of precursors across an upper surface 150 of the substrate 102.

[0016] 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 is used to communicate with the deposition chamber 100 and control the process 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 to measure a temperature within the deposition chamber 100. The plurality of lower lamps 143 are disposed between the lower window 110 and a 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 transmitting material such as quartz. The lower window 110 is a lower dome and is formed of an energy transmitting material such as quartz.

[0017] Between the upper window 108 and the lower window 110, a process volume 136 is formed. Disposed within the process volume 136 is the substrate support 106. 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 volume 136.

[0018] 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 before or after a deposition process is performed. The lift pins 132 may rest on lift pin stops 134 as the substrate support 106 is lowered from a processing position to a transfer position.

[0019] 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 on an opposite side of the flow module 112 from 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 guides are disposed above the purge gas inlet 164. A liner 163 is disposed on an inner surface of the flow module 112 to protect the flow module 112 from reactive gases used during the deposition process. The process gas inlets 114 and the purge gas inlets 164 are positioned to flow gases parallel to an upper surface 150 of a substrate 102 disposed within the process volume 136. The process gas inlets 114 are 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 .

[0020] The one or more exhaust gas outlets 116 are 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 310 (FIG. 3A) and is configured to assist in the controlled deposition of a layer onto the substrate 102.

[0021] 2 illustrates a cross-sectional plan view of the deposition chamber 100 of FIG. 1 according to an embodiment of the present disclosure. The deposition chamber 100 includes an injector 202 disposed across from 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 at least partially through or may be part of the flow module 112. The exhaust system 178 is disposed on an opposite side of the process volume 136 from the injector 202. The exhaust system 178 may be formed through, attached to, or part of the flow module.

[0022] The exhaust system 178 further includes at least one exhaust passage body 204a, 204b. The exhaust passage body 204a, 204b forms an exhaust path for gases exiting the process volume 136 before entering the exhaust collector 206. As shown in FIG. 2, there is a first exhaust passage body 204a and a second exhaust passage body 204b. The first exhaust passage body 204a and the second exhaust passage body 204b are mirror images and may be of similar size and configuration. In other embodiments, there may be more or fewer exhaust passage bodies 204a, 204b. In some embodiments, there is only one exhaust passage body such that two exhaust passage bodies 204a, 204b are integrated into a single body. In still other embodiments, there may be more than two exhaust passage bodies, such as three exhaust passage bodies 204a, 204b. The size and configuration of the exhaust passage bodies 204a, 204b may vary depending on the size and operation of the deposition chamber 100.

[0023] Both the first exhaust passage body 204a and the second exhaust passage body 204b are coupled to an exhaust collector 206 at the ends of the exhaust passage bodies 204a, 204b opposite the treatment volume 136. The exhaust collector 206 is configured to collect exhaust from the first exhaust passage body 204a and the second exhaust passage body 204b. The exhaust collector 206 narrows as the exhaust collector 206 extends away from the exhaust passage bodies 204a, 204b.

[0024] 3A illustrates a cross-sectional plan view of the exhaust system 178 of the deposition chamber 100 of FIG. 1 according to an embodiment of the present disclosure. The exhaust system 178 is configured to control the exhaust gas flow exiting the process volume 136 before flowing over one or more growth monitors 310. Increasing the flow rate over the growth monitor 310 compared to the flow rate at the inlet of the exhaust passage body 204a, 204b promotes film growth on the growth monitor 310. Thus, the width of each of the exhaust passage bodies 204a, 204b narrows from the inlet width W1 to the outlet width W2 to increase the flow rate. A fin array 314 and one or more baffles 304 are positioned within each of the exhaust passage bodies 204a, 204b to allow the exhaust passage bodies 204a, 204b to narrow while mitigating the effect of narrowing the flow path of the process gas through the process volume 136.

[0025] As the process gas exits the process volume 136 and enters the exhaust system 178, it flows in a first flow path 318. The first flow path 318 is primarily parallel to the top surface 150 of the substrate 102 and the gas flow exiting the injector 202. The process gas enters the exhaust system 178 through exhaust inlet openings 305a, 305b disposed through each of the exhaust passage bodies 204a, 204b. Thus, the first exhaust inlet opening 305a is disposed through a first end of the first exhaust passage body 204a, while the second exhaust inlet opening 305b is disposed through a first end of the second exhaust passage body 204b. The exhaust inlet openings 305a, 205b are in fluid communication with the exhaust plenums 312a, 312b. The exhaust plenums 312a, 312b are disposed within each of the exhaust passage 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.

[0026] Each of the exhaust inlet openings 305a, 305b has an inlet width W1. 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, such as about 100 mm to about 155 mm. Thus, the inlet width W1 is less than or equal to half the width of the throughput 136.

[0027] The exhaust outlet openings 308a, 308b are disposed on the exhaust passage body 204a, 204b opposite the exhaust inlet openings 305a, 305b. Thus, the first exhaust outlet opening 308a is disposed on the second side of the first exhaust passage body 204a opposite 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 passage body 204b opposite the first side and is in fluid communication with the second exhaust plenum 312b. The width of the exhaust outlet openings 308a, 308b is smaller than the width of the exhaust inlet openings 305a, 305b. The exhaust outlet openings 308a, 308b have an outlet width W2 of about 15 mm to about 110 mm, for example about 20 mm to about 100 mm, for example about 20 mm to about 40 mm. The outlet width W2, which is smaller than the inlet width W1, allows a high concentration of process gas to flow over the growth monitor 310.

[0028] The ratio of the inlet width W1 to the outlet width W2 is from about 2:1 to about 20:1, such as from about 3:1 to about 10:1, such as from about 4:1 to about 8:1. The ratio of the inlet width W1 to the outlet width W2 allows for good film growth on the growth monitor 310 while reducing the impact of reducing the outlet width W2 on backpressure and flow path through the throughput 136.

[0029] The process gas flowing through the deposition chamber 100 enters the exhaust passage body 204a, 204b through the exhaust inlet openings 305a, 305b while in the first flow path 318 before changing to the second flow path 320 as the one or more baffles 304 narrow the exhaust plenums 312a, 312b to an exit width W2 adjacent the exhaust outlet openings 308a, 308b. The second flow path 320 directs the process gas toward the centerline C of the exhaust system and toward one side of the exhaust plenums 312a, 312b, e.g., toward the inside of the exhaust plenums 312a, 312b. As the process gas flows through the exhaust outlet openings 308a, 308b, the path of the process gas is changed to a third flow path 322. The third flow path 322 is a condensation flow path. The third flow path 322 is disposed through the collector plenum 316. Collector plenum 316 is a plenum disposed within exhaust collector 206 .

[0030] A fin array 314 disposed within each of the exhaust passage bodies 204a, 204b is configured to maintain a first flow path 318 through at least a portion of the exhaust plenums 312a, 312b. The fin array 314 includes a plurality of fins 302 such that a first plurality of fins 302 is disposed within the first exhaust plenum 312a of the first exhaust passage body 204a. Each of the first plurality of fins 302 extends from the first exhaust inlet opening 305a toward the first exhaust outlet opening 308a. A second plurality of fins 302 is disposed within the second exhaust plenum 312b and the second exhaust passage body 204b. Each of the second plurality of fins 302 extends from the second exhaust inlet opening 305b toward the second exhaust outlet opening 308b. The fin array 314 is configured to maintain good flow control through the throughput 136 and extend from a location adjacent the exhaust inlet openings 305a, 305b.

[0031] The number of fins 302 in the fin array 314 can be at least two fins 302, such as at least four fins 302, such as at least five fins 302, such as from five fins 302 to about 30 fins 302, such as from five fins 302 to about 20 fins 302. The number of fins 302 creates smaller gaps between each adjacent fin 302, which helps control the first flow path 318.

[0032] One or more growth monitors 310 are disposed within the fin array 314, such as between two adjacent fins 302. Two or more growth monitors 310 may be disposed within each fin array 314 of both the first exhaust passage body 204a and the second exhaust passage body 204b. The growth monitors 310 within the fin array 314 can help provide measurements of growth rates at different radial locations on the substrate 102.

[0033] Each of the fins 302 in the fin array 314 are parallel to one another. The fins 302 extend in a direction parallel to the desired first flow path 318 and parallel to the gas exiting the injector 202. Other configurations of the fin array 314 are contemplated. In some embodiments, each of the fins 302 are of similar length. In other embodiments, each of the fins 302 do not necessarily have to be of the same length, such that the fins 302 closer to the centerline C of the throughput 136 and exhaust system 178 are shorter than the fins 302 further from the centerline C.

[0034] As the process gas exits the fin array 314, it flows into a main portion 311 of the exhaust plenums 312a, 312b. The main portion 311 of the exhaust plenums 312a, 312b is open space, which may help reduce backpressure that would build up if the fin array 314 extended all the way to the baffle 304. In some embodiments, there is a gap of at least 5 mm, for example about 5 mm to about 40 mm, between the end of the fin array 314 and the nearest portion of the baffle 304.

[0035] The baffles 304 extend from an outer surface 328 of each of the exhaust passage bodies 204a, 204b toward an inner surface 330 of each of the exhaust passage bodies 204a, 204b. The outer surface 328 is the inner surface of the exhaust plenums 312a, 312b that is furthest from the centerline C. The inner surface 330 is the inner surface of the exhaust plenums 312a, 312b that is closest to the centerline C. Thus, the baffles 304 in the first exhaust passage body 204a extend from the outer surface 328 of the first exhaust plenum 312a toward the inner surface 330 of the first exhaust plenum 312a or toward the centerline C of the exhaust system 178. The baffles 304 in the second exhaust passage body 204b extend from the outer surface 328 of the second exhaust plenum 312b toward the inner surface 330 of the second exhaust plenum 312b or toward the centerline C of the exhaust system 178.

[0036] The baffles 304 extend 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, and thus the angle φ is greater than about 90 degrees, such as from about 100 degrees to about 170 degrees, such as from about 100 degrees to about 160 degrees, such as from about 110 degrees to about 145 degrees. The angle at which the baffle plates 304 are positioned helps control the speed limit of the exhaust plenums 312a, 312b. The baffle plates 304 are positioned at an angle other than 0 degrees or 90 degrees relative to the orientation of the fins 302, such as between about 10 degrees and about 80 degrees relative to the orientation of the fins 302. The baffle plate 304 extends over more than 50% of the width of each of the exhaust plenums 312a, 312b, for example, over 60% of the width of each of the exhaust plenums 312a, 312b, for example, over 70% of the width of each of the exhaust plenums 312a, 312b. In some embodiments, the baffle plate 304 has a radius of curvature defined from the center of the throughput 136 of the deposition chamber 100 to the gas guide surface 332. In some embodiments, the radius of curvature varies across the gas guide surface 332 such that a portion of the gas guide surface 332 closer to the inner surface 330 has a smaller radius of curvature. The radius of curvature of the gas guide surface 332 may be other than the radius from the center of the throughput 136. Each baffle plate 304 has a gas guide surface 332. The gas guide surface 332 is the surface of the baffle plate 304 that faces the main portion 311 of the exhaust plenums 312a, 312b and the fin array 314.

[0037] The baffle 304 may have either a curved gas guide surface 332, a straight gas guide surface 332, or a multi-faceted gas guide surface 332. Although the gas guide surface 332 is shown as curved in FIG. 3A, it may be straight in some embodiments. In a curved embodiment, the gas guide surface 332 follows the perimeter of a circle, an ellipse, a hyperbola, or a parabola. The curved surface reduces vortexes or turbulence in the gas flow path, allowing for better gas flow control. The curvature of the gas guide surface 332 may vary depending on the size of the deposition chamber 100 and the size of the exhaust system 178. A gas guide surface 332 with a large radius of curvature allows for smooth guidance of the gas flow through the exhaust plenums 312a, 312b.

[0038] The exhaust outlet openings 308a, 308b are disposed between an innermost portion of each of the baffles 304 and an inner surface 330 of each of the exhaust plenums 312a, 312b. The first exhaust outlet opening 308a is disposed in 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 in the second exhaust plenum 312b and connects the second exhaust plenum 312b to the collector plenum 316.

[0039] One or more growth monitors 310 are positioned either within the exhaust outlet openings 308a, 308b or immediately downstream of the exhaust outlet openings 308a, 308b. A first growth monitor 310 is positioned either within the first exhaust outlet opening 308a or immediately downstream of the exhaust outlet opening 308a. A second growth monitor 310 is positioned either within the second exhaust outlet opening 308b or immediately downstream of the second exhaust outlet opening 308b. A growth monitor 310 positioned immediately downstream of the exhaust outlet openings 308a, 308b is defined as a growth monitor 310 positioned within 10 mm of the exhaust outlet openings 308a, 308b and away from the fin array 314.

[0040] The baffle 304 narrows the passageway through which the exhaust gas passes through the exhaust plenums 312a, 312b, thus increasing the density or concentration of the exhaust gas flowing over the growth monitor 310. The growth monitor 310 is disposed on either the top 326 or bottom 327 (FIG. 3B) of the exhaust plenums 312a, 312b such that the growth monitor 310 does not block the third flow path 322, but instead is in line with the third flow path 322. The growth monitor 310 is at least partially located within the collector plenum 316.

[0041] The exhaust gases pass through the growth monitor 310 and into the collector plenum 316 before being removed from the exhaust collector 206 through the conduit openings 306 (FIG. 3B) in the exhaust conduit 323. The width of the collector plenum 316 adjacent the exhaust outlet openings 308a, 308b is wider than the exhaust outlet openings 308a, 308b such that the width of the collector plenum 316 adjacent each of the exhaust outlet openings 308a, 308b is similar to the entrance width W1 and the total width of the collector plenum 316 is similar to or greater than twice the entrance width W1.

[0042] The conduit opening 306 is located in a portion of the collector plenum 316 opposite the exhaust outlet openings 308a, 308b. The conduit opening 306 is configured to allow exhaust gases in the exhaust collector 206 to be discharged through an exhaust conduit 323 to the exhaust pump 157. Adjacent to the conduit opening 306 is another growth monitor 310 in the collector plenum 316. The growth monitor 310 adjacent to the conduit opening 306 is located on the back sidewall 321 (FIG. 3B) of the collector plenum 316 furthest from the exhaust outlet openings 308a, 308b. In some embodiments, the growth monitor 310 is located directly above the conduit opening 306 or within the conduit opening 306, for example, within the top of the exhaust conduit 323.

[0043] At least the fins 302 and the baffle 304 are formed of or coated with a material having a high thermal conductivity, such as a material having a thermal conductivity of greater than about 100 W / m°K, e.g., greater than about 150 W / m°K, e.g., 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 gases flowing through the exhaust plenums 312a, 312b before flowing over the growth monitor 310. In some embodiments, at least a portion of the walls forming the exhaust plenums 312a, 312b are coated with a high thermal conductivity material similar to the fins 302 and the baffle 304. The inside of the exhaust collector 206 may be coated with a high thermal conductivity material as well. The high thermal conductivity material may be silicon carbide (SiC). Other suitable high thermal conductivity materials are contemplated. In some embodiments, the fins 302 and baffles 304 are formed of graphite and coated with silicon carbide. The high thermal conductivity material conducts heat away from the process volume 136 and reduces the cooling rate of the exhaust gases flowing through the exhaust plenums 312a, 312b. Keeping the exhaust gases heated before flowing over the growth monitor 310 allows for more consistent film formation on the growth monitor 310 and provides a more accurate estimate of the film growth rate in the process chamber.

[0044] Figure 3B illustrates a cross-sectional side view of the exhaust system 178 of the deposition chamber 100 of Figure 1 according to an embodiment of the present disclosure. As shown in Figure 3B, 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 positioned adjacent to the processing volume 136.

[0045] 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 a top surface 326 and a bottom surface 329 of the exhaust plenums 312a, 312b. Growth monitors in the fin array 314 are positioned on the top surface 326.

[0046] The exhaust collector 206 is connected to the rear end of the exhaust system 178. The exhaust collector 206 includes a top surface 324, a bottom surface 327, and a back sidewall 321. A growth monitor 310 is positioned on the top surface 324 of a collector plenum 316 within the exhaust collector 206, immediately downstream of the exhaust outlet openings 308a, 308b. Another growth monitor 310 is disposed on the back sidewall 321 of the collector plenum 316. The positioning of the growth monitors 310 allows for accurate film growth rate measurements by each of the growth monitors 310. Measurements from each of the growth monitors 310 can be mapped to ascertain differences in growth rate across different locations on the substrate 102.

[0047] The 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 collector plenum 316.

[0048] In some embodiments, more or less growth monitors 310 may be utilized within the exhaust system 178. In some embodiments, only the growth monitors 310 adjacent the exhaust outlet openings 308a, 308b are disposed within the exhaust system 178. In other embodiments, the growth monitors 310 adjacent the exhaust outlet openings 308a, 308b may be a single growth monitor 310. In yet other embodiments, a growth monitor 310 adjacent the exhaust outlet openings 308a, 308b and a growth monitor 310 on the rear sidewall 321 of the collector plenum 316 are utilized.

[0049] 4 illustrates a growth monitor 310 for use in the deposition chamber 100 of FIG. 1 according to an embodiment of the present disclosure. The growth monitor 310 includes a sensor holder 402, a crystal 406 disposed within the sensor holder 402, a back contact 408 contacting a first side 422 of the crystal 406, a front contact 410 contacting a second side 424 of the crystal 406, a protective coating 416 disposed on the second side 424 of the crystal 406, and a sensor opening 414 disposed through the sensor holder 402 and exposing the protective coating 416 to gases flowing through the exhaust system 178.

[0050] The growth monitor 310 is configured to be positioned within the deposition chamber 100 and therefore takes into account the reactive process chemistry within the exhaust system 178. The materials of the protective coating 416, as well as the sensor holder 402, back contact 408 and front contact 410, affect the reactivity of the growth monitor 310 with the process chemistry within the deposition chamber 100. Thus, the material composition is selected to reduce the reactivity of the growth monitor 310 with the process chemistry within the deposition chamber 100 while still allowing accurate film thickness measurements with the growth monitor 310.

[0051] The sensor holder 402 serves as a case in which the back contact 408, the front contact 410, and the crystal 406 are disposed. The sensor holder 402 is formed in multiple parts, including a first part 405 and a second part 404. The first part 405 has a cavity formed therein in which the back contact 408 is disposed. The crystal 406 is also located within the cavity and in contact with the back contact 408.

[0052] The second portion 404 includes a sensor opening 414 disposed therethrough and is positioned on a side of the first portion 405 that includes the cavity. The front contact 410 is positioned between the first portion 405 and the second portion 404. The front contact 410 is held in place by the gripping force of the first portion 405 and the second portion 404. The front contact 410 is a ring such that the front contact 410 covers an outer portion of the second face 424 of the crystal 406 but does not cover a central portion of the second face 424. A protective coating 416 is disposed within the ring formed by the front contact 410 and contacts the second face 424 of the crystal 406. The protective coating 416 is at least partially disposed within the sensor opening 414 such that the protective coating 416 is exposed to exhaust gases flowing through the exhaust system 178. The protective coating 416 and crystal 406 are held in place at least partially by a gripping force between the first portion 405 and the second portion 404. One or more sealing rings 412 are disposed within the second portion 404 and contact an exposed surface 426 of the protective coating 416. The one or more sealing rings 412 are configured to provide a seal between the atmosphere within the exhaust system 178 and other components of the growth monitor 310 that are not the protective coating 416.

[0053] The protective coating 416 is formed from one of alumina (Al2O3) or a silicon oxide, such as silicon dioxide (SiO2). The protective coating 416 is formed from a material that does not degrade when exposed to epitaxial deposition process conditions or processing gases. The protective coating 416 may be a lens or may be a coating applied to the crystal 406. The protective coating 416 has a thickness of less than about 10 μm, such as from about 1 nm to about 10 nm, from about 1 nm to about 5 nm. The small thickness allows the crystal 406 to be protected without significantly dampening the vibration of the crystal 406.

[0054] At least one of the back contact 408 or the front contact 410 is formed from a gold-containing material, such as a gold alloy or pure gold. Both the back contact 408 and the front contact 410 may be formed from a gold-containing material. The gold-containing material reduces the reactivity of the back contact 408 and the front contact 410 to the chemistry in the deposition chamber 100. In some embodiments, the back contact 408 and the front contact 410 are coated with a gold-containing material.

[0055] The cooling mechanism 420 is disposed through the first portion 405 of the sensor holder 402. The cooling mechanism 420 may be a coolant passage disposed through a body of the first portion 405. The cooling mechanism 420 may be a coolant passage configured to receive cooling water.

[0056] The one or more sealing rings 412 are formed from a polymer or plastic that is compatible with epitaxial deposition processes at temperatures of about 200° C. In some embodiments, the one or more sealing rings 412 can be an o-ring or another type of gasket.

[0057] 5 illustrates a control schematic 500 for use in the deposition chamber 100 of FIG. 1 according to an embodiment of the present disclosure. The controller 120 is configured to receive data or input as sensor readings 502 from each of the growth monitors 310. The controller 120 includes or is in communication with a system model 506 of the deposition chamber 100. The system model 506 includes a heating model and a gas flow module. The system model 506 is a program configured to estimate gas flows and heating in the deposition chamber 100 throughout the deposition process. The controller 120 is further configured to store the readings and calculations 504.

[0058] The readings and calculations 504 include previous sensor readings 502, such as any previous sensor measurements in the deposition chamber 100. The readings and calculations 504 further include stored calculations from after the sensor readings 502 have been measured by the controller 120 and run through the system model 506. Thus, the controller 120 is configured to both obtain the readings and calculations 504 and to store the readings and calculations 504 for future use. By maintaining the previous readings and calculations, the controller 120 can adjust the system model 506 over time to reflect more accurate versions of the deposition chamber 100.

[0059] In the embodiments described herein, the controller 120 includes a programmable central processing unit (CPU) operating with memory and mass storage, input controls, and a display (not shown). The controller 120 monitors the precursor, process gas, and purge gas flows. Support circuitry is connected to the CPU to support the processor in a conventional manner. In some embodiments, the controller 120 includes multiple controllers 120, such 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, the system model 506 and the stored readings and calculations 504 are all stored in the controller 120.

[0060] The controller 120 is configured to control the heating and gas flow through the deposition chamber 100 by providing output to lamps and gas flow controllers 508. The lamps and gas flow controllers 508 include upper lamps 141, lower lamps 143, process gas source 151, purge gas source 162, and exhaust pump 157. The controller 120 can also control an operating assembly 121 within the deposition chamber 100.

[0061] The controller 120 is configured to adjust the output to each of the lamps and gas flow controllers 508 based on the sensor readings 502, the system model 506, and the stored readings and calculations 504. The controller 120 includes built-in software and compensation algorithms to calibrate 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 as the substrate 102 exits the deposition chamber or between process operations to provide a reference for the film thickness growth rate measured using the growth monitor 310. The controller 120 can include machine learning algorithms and can use regression or clustering techniques. The algorithms can be unsupervised or supervised.

[0062] 6 illustrates a method 600 for adjusting process conditions in the deposition chamber 100 of FIG 1 according to an embodiment of the present disclosure. The method 600 utilizes a growth monitor 310 in the deposition chamber 100 and a controller 120 described herein to improve film thickness uniformity and characteristics across the substrate 102.

[0063] 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. Gases are flowed through process volume 136 from process gas inlet 114 and purge gas inlet 164 before being removed through exhaust gas outlet 116.

[0064] When the first substrate is being processed in the processing chamber, the growth monitor 310 is used to measure the film thickness growth on the monitor during another operation 604. The measurement of the film thickness growth on the growth monitor 310 is performed as a rolling operation. A controller, such as the controller 120, is configured to receive input from a combination of the growth monitors 310 described with respect to FIGS. 3A-3B. The input is used to estimate the film growth on the first substrate. Once the processing of the first substrate in the processing chamber is completed, the film thickness can be measured using one or more other non-contact sensors in the processing chamber or in an adjacent chamber during another operation 606. The measurement of the film growth on the first substrate during operation 606 is performed in a non-destructive manner, such as by using one or more non-contact sensors. The non-contact sensor may be a laser thickness gauge and may take multiple individual measurements across the surface of the first substrate or may scan the length of the first substrate.

[0065] The non-contact sensors used during operation 606 are not necessarily utilized for film thickness measurements during substrate processing because radiation from the process gases and heating sources interfere with the sensor readings, reducing the sensitivity and accuracy of the readings. Thus, the use of non-contact sensors utilized during operation 606 limits the ability to determine and manage changes in heating and gas flows within the process volume during substrate processing. The growth monitor 310 advantageously enables adjustments of process conditions, such as heating and gas flows, while the first substrate is being processed.

[0066] Measurement of the film growth on the first substrate allows the growth rate on the first substrate to be calculated 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 allows the process chamber model to be adjusted during another operation 610. Adjusting the process chamber model during operation 610 allows the growth monitor 310 to be better used for the particular process. Once the model is adjusted, processing of another substrate, such as a second substrate, is performed and operations 602, 604, 606, 608, 610 are repeated. Operations 602, 604, 606, 608, 610 of method 600 can be looped to continually adjust the accuracy of the process chamber model during operation 610 to improve film thickness growth results. If preventive maintenance is performed on the process chamber, the process chamber model may be reset or adjusted and method 600 begins again. Thus, resulting in a continuous film thickness improvement between each substrate. This further enables precise film thickness and overcomes changes in process chamber characteristics as films build up on surfaces within the process volume or as lamps age.

[0067] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, the scope of which is determined by the claims that follow.

Claims

1. An exhaust passage body applicable to semiconductor substrate processing, a first exhaust plenum; a first exhaust inlet opening formed through a first end of the exhaust passage body and fluidly connected to the first exhaust plenum; a first plurality of fins disposed adjacent the first exhaust inlet opening in the first exhaust plenum; a first exhaust outlet opening formed through the second end of the exhaust passage body and fluidly connected to the first exhaust plenum; a first baffle plate disposed adjacent the first exhaust outlet opening and configured to narrow a first width of the first exhaust plenum; and at least one growth monitor disposed downstream of the first baffle plate and configured to measure a thickness of a material disposed on the growth monitor; an exhaust passage body including

2. The exhaust passage body of claim 1 , wherein said at least one growth monitor is a quartz crystal film thickness monitor.

3. The exhaust passage body of claim 1 , wherein the first baffle plate is oriented to narrow the first exhaust plenum as it extends toward the first exhaust outlet opening.

4. a second exhaust plenum; a second exhaust inlet opening formed through the first end of the exhaust passage body and fluidly connected to the second exhaust plenum; a second plurality of fins disposed adjacent the second exhaust inlet opening in the second exhaust plenum; a second exhaust outlet opening formed through the second end of the exhaust passage body and fluidly connected to the second exhaust plenum; and a second baffle plate disposed adjacent the second exhaust outlet opening and configured to narrow a second width of the second exhaust plenum; The exhaust passage body of claim 3 further comprising:

5. 2. The exhaust passage body of claim 1, wherein the first exhaust inlet opening has an inlet width and the first exhaust outlet opening has an outlet width, a ratio of the inlet width to the outlet width being from about 2:1 to about 20:

1.

6. The exhaust passage body of claim 5 , wherein the first exhaust inlet opening has an inlet width of from about 10 mm to about 210 mm.

7. The exhaust passage body of claim 1 , wherein the first plurality of fins includes at least four fins.

8. The exhaust passage body of claim 7 , wherein each of the first plurality of fins are oriented parallel to one another.

9. 1. An exhaust system applicable to semiconductor substrate processing, comprising: An exhaust passage body, Exhaust plenum, an exhaust inlet opening formed through the first end of the exhaust passage body, the exhaust inlet opening having an inlet width; a plurality of fins disposed adjacent the exhaust inlet opening within the exhaust plenum; an exhaust outlet opening formed through the second end of the exhaust passage body and fluidly connected to the exhaust plenum; at least one baffle plate disposed adjacent the exhaust outlet opening and configured to reduce a width of the exhaust plenum to an outlet width that is less than the inlet width; and at least one growth monitor disposed downstream of the baffle plate and configured to measure a thickness of a material disposed on the growth monitor; An exhaust passage body including: an exhaust collector connected to the exhaust passage body at the exhaust outlet opening; Including, exhaust system.

10. The exhaust system of claim 9 , wherein the at least one growth monitor is a quartz crystal film thickness monitor.

11. The quartz crystal thickness monitor is Sensor holder, A quartz crystal disposed within the sensor holder; a back contact contacting a first face of the crystal; a front contact contacting a second face of the crystal; a protective coating disposed on the second surface of the crystal; and a sensor opening disposed through the sensor holder and exposing the protective coating to gases flowing through the exhaust plenum. The exhaust system of claim 10, comprising:

12. The exhaust system of claim 11 , wherein at least one of the back contact and the front contact comprises a gold material.

13. 12. The exhaust system of claim 11, wherein the protective coating is alumina or silicon dioxide.

14. The exhaust system of claim 9 , wherein the plurality of fins is a material having a thermal conductivity greater than about 100 W / m·K.

15. The exhaust system of claim 14 , wherein the material comprises silicon carbide.

16. The exhaust system of claim 9 , wherein the at least one growth monitor is disposed within the exhaust collector adjacent the exhaust outlet opening.

17. The exhaust system of claim 9 , wherein at least one baffle plate is a curved plate.

18. 1. A processing system applicable to semiconductor substrate processing, comprising: a chamber body that defines a processing space; a substrate support disposed within the processing space of the chamber body; an upper window disposed above the substrate support; a lower window disposed below the substrate support, the upper window and the lower window each further defining the processing space; an injector disposed through one side of the chamber body and configured to introduce a process gas into the process space; an exhaust system disposed through a second face of the chamber body opposite the injector; Exhaust passage body, an exhaust plenum disposed through the exhaust passage body; an exhaust inlet opening formed through a first end of the exhaust passage body, the exhaust inlet opening configured to fluidly connect the exhaust plenum and the process volume; a plurality of fins disposed within the exhaust plenum; an exhaust outlet opening formed through the second end of the exhaust passage body and fluidly connected to the exhaust plenum; at least one baffle plate disposed downstream of the plurality of fins and configured to reduce a width of the exhaust plenum to an exit width that is less than an entrance width; and at least one growth monitor disposed downstream of the baffle plate and configured to measure a thickness of a material disposed on the growth monitor; Exhaust system, including a processing system comprising:

19. 20. The processing system of claim 18, wherein the at least one growth monitor is in communication with a controller configured to determine a growth rate on the growth monitor and adjust at least one of a process gas flow rate, a heating energy level, or an exhaust flow rate.

20. 20. The processing system of claim 19, 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 how to adjust at least one of the process gas flow rate, the heating energy level, or the exhaust flow rate.

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