Control of in-epimetric growth rate of crystal thickness using parametric resonance sensing
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- APPLIED MATERIALS INC
- Filing Date
- 2023-01-13
- Publication Date
- 2026-08-03
Smart Images
Figure 0007899441000001 
Figure 0007899441000002 
Figure 0007899441000003
Abstract
Description
Technical Field
[0001]
[0001] Embodiments of the present disclosure generally relate to apparatuses and methods for manufacturing semiconductor devices. More specifically, the apparatuses disclosed herein relate to an exhaust assembly and a growth rate sensor within a semiconductor process chamber. Methods using them are also disclosed.
Background Art
[0002]
[0002] Semiconductor substrates are processed for various applications including the manufacture of integrated devices and microdevices. During processing, the substrate is positioned on a susceptor within a process chamber. The susceptor is supported by a support shaft that is rotatable about a central axis. Through precise control of a heat source, the substrate is heated uniformly within strict tolerances. The temperature of the substrate can affect the uniformity of the material deposited on the substrate.
[0003]
[0003] The ability to monitor the growth / deposition thickness within a process chamber has a significant impact on throughput and production yield. Currently, in an epitaxial reactor, in situ monitoring of growth / deposition thickness is not generally performed. Currently, the process is time-adjusted to achieve a desired thickness, and then the thickness is measured ex situ outside the process chamber. In conventional attempts to incorporate sensors within the process chamber, there are limitations in resolution, and adding sensors increases the downtime of the process chamber and the ownership cost. Even attempts to offset these costs still do not result in a direct measurement of mass. Also, the substrate processed between the calibration and measurement steps has a reduced deposition rate accuracy due to changes in chamber conditions. Current sensors within the process chamber include pyrometers and pressure sensors, but these do not provide the determination accuracy for desired film growth.
[0004]
[0004] Therefore, there is a need to improve the monitoring of growth rate.
Summary of the Invention
[0005]
[0005] This disclosure generally relates to apparatus and methods for manufacturing semiconductor devices. More specifically, the apparatus disclosed herein relates to exhaust assemblies and growth rate sensors in semiconductor process chambers. Methods of using them are also disclosed.
[0006]
[0006] In another embodiment, an exhaust system for substrate processing is disclosed. The exhaust system includes a first exhaust plenum, a first exhaust inlet opening fluidly connected to the first exhaust plenum, a first group of fins located 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 plate located adjacent to the first exhaust outlet opening and configured to narrow the width of the first exhaust plenum, and at least one growth monitor located downstream of the first baffle plate. The growth monitor is configured to measure the thickness of material deposited on the growth monitor. At least one growth monitor is a parametric resonant sensor.
[0007]
[0007] Another embodiment is a processing system suitable for processing semiconductor substrates. The processing system includes a chamber body forming a process area, a substrate support, an upper window, a lower window, an injector, and an exhaust system. The substrate support is located within the process area of the chamber body. The upper window is located above the substrate support, and the lower window is located below the substrate support. The upper and lower windows define the process area. The injector is located through one side of the chamber body and is configured to introduce process gas into the process area. The exhaust system is located through a second side of the chamber body opposite the injector. The exhaust system includes at least one growth monitor configured to measure the thickness of material deposited on the growth monitor. The growth monitor is a parametric resonant sensor.
[0008]
[0008] In another embodiment, a controller of a process system that stores instructions is disclosed. When executed by the processor, the controller causes the system to process the substrate in a processing chamber by flowing process gas into the process area from a process gas inlet, depositing the gas on the substrate, and exhausting the process gas through an exhaust system. The exhaust system further includes a growth monitor. The growth monitor includes a parametric resonant sensor. The controller further causes the system to deposit process gas on the growth monitor, measure film growth on the growth monitor, calculate the film growth rate on the substrate, and adjust the processing chamber parameters.
[0009]
[0009] In order to understand the features of the present disclosure described above in detail, the present disclosure summarized above will be described more specifically with reference to embodiments illustrated in part in the accompanying drawings. However, it should be noted that the accompanying drawings are merely illustrative embodiments and should not be considered limiting in scope, and the present disclosure may also permit other equally valid embodiments. [Brief explanation of the drawing]
[0010] [Figure 1] This is a schematic diagram of a deposit chamber according to a specific embodiment. [Figure 2] This is a cross-sectional plan view showing the deposition chamber of Figure 1 according to a specific embodiment. [Figure 3A] This is a cross-sectional plan view showing the exhaust system of the deposit chamber in Figure 1 according to a specific embodiment. [Figure 3B] This is a cross-sectional side view showing the exhaust system of the deposition chamber in Figure 1 according to a specific embodiment. [Figure 4A] Figure 1 shows an embodiment of a growth monitor for use in a deposition chamber. [Figure 4B] Figure 1 shows an embodiment of a growth monitor for use in a deposition chamber. [Figure 5] This is a schematic control diagram for use in the deposition chamber shown in Figure 1 according to a specific embodiment. [Figure 6] This figure shows a method for adjusting the process conditions in the deposition chamber of Figure 1 according to an embodiment of the present disclosure. [Figure 7] This figure shows a method for measuring the thickness of material on a substrate in a deposition chamber shown in Figure 1, according to a specific embodiment. [Modes for carrying out the invention]
[0011]
[0018] For ease of understanding, the same reference numerals are used to indicate identical elements common to the drawings whenever possible. It is assumed that elements and features of one embodiment can be usefully incorporated into other embodiments without further detail.
[0012]
[0019] This disclosure relates to an exhaust assembly and a growth rate sensor in a semiconductor process chamber. The growth rate sensor is a parametric resonant film thickness monitor that enables measurement of film thickness on the growth rate sensor. The film thickness on the growth rate sensor is equivalent to the growth rate on the substrate in the process chamber. Using this thickness measurement, one or more process controls can be adjusted within the process region of the process chamber to improve film growth across the entire substrate.
[0013]
[0020] The location and number of parametric resonance monitors improve sensitivity and sensor lifecycle. The configuration of the exhaust system around the parametric resonance monitors can further increase the process gas flow across the monitors, improving the growth rate on the monitors while maintaining or minimizing the gas flow within the process region. Therefore, the exhaust system may include fins and baffles for controlling gas flow. The fins, baffles, and other components of the exhaust system may further be formed from or coated with materials that enhance the heat retention of the process gas as it flows through the exhaust system. This makes film growth on the parametric resonance monitors more predictable.
[0014]
[0021] The software algorithm within the process chamber controller takes growth rate measurements from the parametric resonance monitor and enables calibration of other sensors and process conditions within the process chamber to improve the film thickness growth rate.
[0015]
[0022] Figure 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 used to grow an epitaxial film on a substrate such as a substrate 102. The deposition chamber 100 forms a crossflow of precursor over the upper surface 150 of the substrate 102.
[0016]
[0023] The deposition chamber 100 includes an upper body 156, a lower body 148 positioned below the upper body 156, and a flow module 112 positioned between the upper body 156 and the lower body 148. The upper body 156, the flow module 112, and the lower body 148 form the chamber body. Located 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 illustrated, a controller 120 communicates with the deposition chamber 100 and is used to control processes such as those described herein. The substrate support 106 is positioned between the upper window 108 and the lower window 110. The plurality of upper lamps 141 are positioned 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) positioned within it to measure the temperature inside the deposition chamber 100. Multiple lower lamps 143 are positioned between the lower window 110 and the floor 152. The multiple lower lamps 143 form part of the lower lamp module 145. The upper window 108 is an upper dome and is made of an energy-permeable material such as quartz. The lower window 110 is a lower dome and is made of an energy-permeable material such as quartz.
[0017]
[0024] The process area 136 is formed between the upper window 108 and the lower window 110. The process area 136 has a substrate support 106 disposed therein. The substrate support 106 includes a top surface on which the substrate 102 is placed. The substrate support 106 is attached to a shaft 118. The shaft is connected to an operating assembly 121. The operating assembly 121 includes one or more actuators and / or adjusters that provide movement and / or adjustment of the shaft 118 and / or the substrate support 106 within the process area 136.
[0018]
[0025] The substrate support 106 may include lift pin holes 107 disposed therein. The lift pin holes 107 are sized to accommodate lift pins 132 for lifting the substrate 102 from the substrate support 106 either before or after the deposition process is performed. The lift pins 132 may rest on lift pin stops 134 when the substrate support 106 is lowered from the process position to the transfer position.
[0019]
[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 gas outlets 116. The plurality of process gas inlets 114 and the plurality of purge gas inlets 164 are disposed on the 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 guide is disposed above the purge gas inlet 164. A liner 163 is disposed on the inner surface of the flow module 112 to protect the flow module 112 from reactive gases used during the deposition process. The process gas inlets 114 and the purge gas inlets 164 are positioned to flow gas parallel to the upper surface 150 of the substrate 102 disposed within the process region 136. The process gas inlets 114 are fluidly connected to a process gas source 151. The purge gas inlets 164 are 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]
[0027] The one or more exhaust gas outlets 116 are further connected to or include an exhaust system. The exhaust system fluidly connects the one or more exhaust gas outlets 116 and the exhaust pump 157. The exhaust system described herein includes one or more growth monitors 310 (FIG. 3A) and is configured to assist in the controlled deposition of layers on the substrate 102.
[0021]
[0028] Figure 2 is a cross-sectional plan view showing the deposition chamber 100 of Figure 1 according to an embodiment of the present disclosure. The deposition chamber 100 includes an injector 202 located opposite the exhaust system 178. The injector 202 includes a process gas inlet 114 and is fluidly coupled to a process gas source 151. The injector 202 may be located through or as part of at least a portion of the flow module 112. The exhaust system 178 is located on the opposite side of the process region 136 from the injector 202. The exhaust system 178 is formed through or attached to the flow module or as part of the flow module.
[0022]
[0029] The exhaust system 178 further includes at least one exhaust passage body 204a, 204b. The exhaust passage bodies 204a, 204b form an exhaust path for gases leaving the process area 126 before entering the exhaust collector 206. As shown in Figure 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 similar in 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, and two exhaust passage bodies 204a, 204b are integrated into a single body. In yet another embodiment, there may be three or more exhaust passage bodies, such as three exhaust passage bodies 204a, 204b. The size and configuration of the exhaust passage bodies 204a, 204b may be changed depending on the size and process of the deposition chamber 100.
[0023]
[0030] Both the first exhaust passage 204a and the second exhaust passage 204b are coupled to an exhaust collector 206 at the ends of the exhaust passages 204a and 204b opposite to the process region 136. The exhaust collector 206 is configured to collect exhaust gas from the first exhaust passage 204a and the second exhaust passage 204b. The exhaust collector 206 narrows as it moves away from the exhaust passages 204a and 204b.
[0024]
[0031] Figure 3A is a cross-sectional plan view showing the exhaust system 178 of the deposition chamber 100 of Figure 1 according to an embodiment of the present disclosure. The exhaust system 178 is configured to control the exhaust gas flow leaving the process region 126 before it flows onto one or more growth monitors 310. As the flow rate on the growth monitors 310 increases relative to the flow rate at the inlets of the exhaust passages 204a and 204b, film growth on the growth monitors 310 is promoted. Therefore, the width of each exhaust passage 204a and 204b is narrowed from the inlet width W1 to the outlet width W2 to increase the flow rate. Fin arrays 314 and one or more baffles 304 are positioned within each exhaust passage 204a and 204b, allowing the exhaust passages 204a and 204b to be narrowed while reducing the effect of the narrowing on the flow path of the process gas through the process region 136.
[0025]
[0032] When process gas flows out of the process area 136 into the exhaust system 178, the process gas flows through a first flow path 318. The first flow path 318 is primarily parallel to the surface of the substrate 136, and the gas flows out from the injector 202. The process gas flows into the exhaust system 178 through exhaust inlet openings 305a and 305b, which are located through the exhaust passages 204a and 204b, respectively. Thus, the first exhaust inlet opening 305a is located through the first end of the first exhaust passage 204a, and the second exhaust inlet opening 305b is located through the first end of the second exhaust passage 204b. The exhaust inlet openings 305a and 305b are fluidly connected to the exhaust plenums 312a and 312b. The exhaust plenums 312a and 312b are located within the respective exhaust passages 204a and 204b. Therefore, the first exhaust plenum 312a is located within the first exhaust passage body 204a, and the second exhaust plenum 312b is located within the second exhaust passage body 204b. The first exhaust inlet opening 305a is fluidly connected to the first exhaust plenum 312a, and the second exhaust inlet opening 305b is fluidly connected to the second exhaust plenum 312b.
[0026]
[0033] Each of the exhaust inlet openings 305a and 305b has an inlet width W1. The inlet width W1 ranges from approximately 10 mm to approximately 210 mm, for example, from approximately 45 mm to approximately 210 mm, for example, from approximately 75 mm to approximately 175 mm, for example, from approximately 100 mm to approximately 155 mm. Therefore, the inlet width W1 is less than half the width of the process area 136.
[0027]
[0034] The exhaust outlet openings 308a and 308b are located on the opposite side of the exhaust inlet openings 305a and 305b of the exhaust passage bodies 204a and 204b. Therefore, the first exhaust outlet opening 308a is located on the second side of the first exhaust passage body 204a, opposite to the first side, and is fluidly connected to the first exhaust plenum 312a. The second exhaust outlet opening 308b is located on the second side of the second exhaust passage body 204b, opposite to the first side, and is fluidly connected to the second exhaust plenum 312b. The exhaust outlet openings 308a and 308b are narrower than the exhaust inlet openings 305a and 305b. The exhaust outlet openings 308a and 308b have an outlet width W2 of approximately 15 mm to approximately 110 mm, for example, approximately 20 mm to approximately 100 mm, for example, approximately 20 mm to approximately 40 mm. Because the outlet width W2 is smaller than the inlet width W1, a higher concentration of process gas can flow over the growth monitor 310.
[0028]
[0035] The ratio of the inlet width W1 to the outlet width W2 is approximately 2:1 to 20:1, for example, approximately 3:1 to 10:1, or for example, approximately 4:1 to 8:1. The ratio of the inlet width W1 to the outlet width W2 allows for sufficient film growth on the growth monitor 310 and reduces the impact of the reduced outlet width W2 on back pressure and the flow path through the process region 136.
[0029]
[0036] The process gas flowing through the deposition chamber 100 enters the exhaust passage bodies 204a, 204b through the exhaust inlet openings 305a, 305b while it is in the first passage 318 before it changes to a second passage 320 that narrows the exhaust plenums 312a, 312b to an outlet width W2 adjacent to the outlet openings 308a, 308b, through one or more baffles 304. The second passage 320 directs the process gas toward the centerline C of the exhaust system toward one side of the exhaust plenums 312a, 312b, for example, toward the inside of the exhaust plenums 312a, 312b. Once the process gas has flowed through the outlet openings 308a, 308b, the path of the process gas changes to a third passage 322. The third passage 322 is a condensation passage. The third passage 322 is arranged to pass through the collector plenum 316, which is a plenum located within the exhaust collector 206.
[0030]
[0037] The fin array 314, located within each exhaust passage body 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 are located within the first exhaust plenum 312a of the first exhaust passage body 204a. A second plurality of fins 302 are located within the second exhaust plenum 312b and the second exhaust passage body 204b. The fin array 314 is configured to maintain good flow control through the process region 136 and extends from a position adjacent to the exhaust inlet openings 305a, 305b.
[0031]
[0038] The number of fins 302 in the fin array 314 may be at least four fins 302, for example at least five fins 302, for example five fins 302 to about 30 fins 302, for example five fins 302 to about 20 fins 302. The number of fins 302 helps to reduce the gap between each adjacent fin 302, which helps to control the first flow path 318.
[0032]
[0039] One or more growth monitors 310 are positioned within the fin array 314, for example, between two adjacent fins 302. Two or more growth monitors 310 may be positioned within each fin array 314 of both the first exhaust passage 204a and the second exhaust passage 204b. The growth monitors 310 within the fin array 314 can be correlated with different growth monitors 310 at different locations on the substrate, which may help provide measurements of the growth rate at different locations on the substrate 102.
[0033]
[0040] Each fin 302 in the fin array 314 is parallel to one another. The fins 302 extend in a direction parallel to the desired first flow path 318 and parallel to the gas flowing out of the injector 202. Other configurations of the fin array 314 are also possible. In some embodiments, each fin 302 is of similar length. In other embodiments, each fin 302 is not necessarily of the same length; for example, fins 302 closer to the centerline C of the process region 136 and the exhaust system 178 are shorter than fins 302 further from the centerline C.
[0034]
[0041] As the process gas exits the fin array 314, it flows into the main portions 311 of the exhaust plenums 312a and 312b. The main portions 311 of the exhaust plenums 312a and 312b are open spaces, which can help reduce the back pressure that would accumulate if the fin array 314 extended to the baffle plate 304. In some embodiments, there is a gap of at least 5 mm between the end of the fin array 314 and the nearest portion of the baffle plate 304, for example, a gap of about 5 mm to about 40 mm.
[0035]
[0042] The baffle plate 304 extends from the outer surface 328 of each exhaust passage body 204a, 204b toward the inner surface 330 of each exhaust passage body 204a, 204b. The outer surface 328 is the inner surface of the exhaust plenums 312a, 312b furthest from the centerline C, and the inner surface 330 is the inner surface of the exhaust plenums 312a, 312b closest to the centerline C. Therefore, the baffle plate 304 in the first exhaust passage body 204a extends from the outer surface 328 of the first exhaust plenum 312a toward the inner surface 330 of the first exhaust passage plenum 312a or toward the centerline C of the exhaust system 178. The baffle plate 304 in the second exhaust passage body 204b extends from the outer surface 328 of the second exhaust plenum 312b toward the inner surface 330 of the second exhaust passage plenum 312b or toward the centerline C of the exhaust system 178.
[0036]
[0043] The baffle plate 304 extends at an angle φ with respect to the outer surface 328 of each exhaust plenum 312a, 312b. The angle φ is the inner angle facing the fin array 314. The angle φ is obtuse and greater than about 90 degrees, for example, from about 100 degrees to about 170 degrees, for example, from about 100 degrees to about 160 degrees, for example, from about 110 degrees to about 145 degrees. The angle at which the baffle plate 304 is positioned helps to control the speed limit of the exhaust plenums 312a, 312b. The baffle plate 304 is positioned at an angle other than 0 degrees or 90 degrees with respect to the orientation of the fins 302, for example, at an angle of about 10 degrees to about 80 degrees with respect to the orientation of the fins 302. The baffle plate 304 extends over more than 50% of the width of each exhaust plenum 312a, 312b, for example, more than 60% of the width of each exhaust plenum 312a, 312b, for example, more than 70% of the width of each exhaust plenum 312a, 312b. In some embodiments, the baffle plate 304 has a radius of curvature defined as the radius from the center of the process area 136 of the deposition chamber 100 to the gas guide surface 332. In some embodiments, the radius of curvature varies over the entire gas guide surface 332, for example, the 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 a radius other than the radius from the center of the process area 136. Each baffle plate 304 has a gas guide surface 332. The gas guide surface 332 is the surface of the baffle plate 304 facing the main portion 311 of the exhaust plenums 312a and 312b, as well as the fin array 314.
[0037]
[0044] The baffle plate 304 may have a curved gas guide surface 332, a straight gas guide surface 332, or a multifaceted gas guide surface 332. Although the gas guide surface 332 is shown as straight in Figure 3A, in some embodiments the gas guide surface 332 may be curved so that it follows the circumference of a circle, ellipse, hyperbola, or parabola. The curved surface can reduce vortices or turbulence in the gas flow path, enabling better gas flow control. The curvature of the gas guide surface 332 can be changed according to the size of the deposit chamber 100 and the size of the exhaust system 178.
[0038]
[0045] The exhaust outlet openings 308a and 308b are located between the innermost part of each baffle plate 304 and the inner surface 330 of each exhaust plenum 312a and 312b. The first exhaust outlet opening 308a is located 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 located within the second exhaust plenum 312b and connects the second exhaust plenum 312b to the collector plenum 316.
[0039]
[0046] One or more growth monitors 310 are located either within the exhaust outlet openings 308a and 308b, or immediately downstream of the exhaust outlet openings 308a and 308b. The first growth monitor 310 is located within the first exhaust outlet opening 308a or immediately downstream of the exhaust outlet opening 308a. The second growth monitor 310 is located within the second exhaust outlet opening 308b or immediately downstream of the second exhaust outlet opening 308b. Placing the growth monitor 310 immediately downstream of the exhaust outlet openings 308a and 308b is defined as positioning the growth monitor 310 within 10 mm of the exhaust outlet openings 308a and 308b, away from the fin array 314.
[0040]
[0047] The baffle plate 304 narrows the passage through which the exhaust gas passes through the exhaust plenums 312a and 312b, and therefore increases the density or concentration of the exhaust gas flowing over the growth monitor 310. The growth monitor 310 is positioned on either the top surface 326 or the bottom surface 327 (Figure 3B) of the exhaust plenums 312a and 312b, so that the growth monitor 310 does not block the third passage 322, but is instead aligned with the third passage 322. The growth monitor 310 is located at least partially inside the collector plenum 316.
[0041]
[0048] The exhaust gas passes over the growth monitor 310 and enters the collector plenum 316 before being removed from the exhaust collector 206 through the conduit opening 306 (Figure 3B) of the exhaust conduit 323. Since the width of the collector plenum 316 adjacent to the outlet openings 308a and 308b is wider than the outlet openings 308a and 308b, the width of the collector plenum 316 adjacent to each outlet opening 308a and 308b is the same as the inlet width W1, and the total width of the collector plenum 316 is the same as the inlet width W1, or more than twice the inlet width W1.
[0042]
[0049] The conduit opening 306 is located on the side of the collector plenum 316 opposite to the outlet openings 308a and 308b. The conduit opening 306 is configured to allow exhaust gas from the exhaust collector 206 to be discharged to the exhaust pump 157 through the exhaust conduit 323. Inside the collector plenum 316 is another growth monitor 310 adjacent to the conduit opening 306. The growth monitor 310 adjacent to the conduit opening 306 is located on the rear side wall 321 (Figure 3B) of the collector plenum 316, furthest from the outlet openings 308a and 308b. In some embodiments, the growth monitor 310 may be located directly above or inside the conduit opening 306, for example, above the exhaust conduit 323.
[0043]
[0050] At least the fins 302 and baffle plates 304 may be formed from or coated with a material having high thermal conductivity, for example, a material having a thermal conductivity of about 100 W / m·°K or more, for example, about 150 W / m·°K or more, for example, about 175 W / m·°K or more. The material of the fins 302 is selected to reduce contamination of the deposition chamber 100 while maintaining the temperature of the exhaust gas 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 is coated with a high thermal conductivity material similar to that of the fins 302 and baffle plates 304. The interior of the exhaust collector 206 may also be coated with a high thermal conductivity material. The high thermal conductivity material may be silicon carbide (SiC). Other suitable high thermal conductivity materials are also conceivable. In some embodiments, the fins 302 and baffle plates 304 are formed of graphite and coated with silicon carbide. The highly thermally conductive material conducts heat from the process area 136 and reduces the cooling rate of the exhaust gas flowing through the exhaust plenums 312a and 312b. Preheating the exhaust gas before flowing it onto the growth monitor 310 allows for more stable film formation on the growth monitor 310, and enables a more accurate estimation of the film growth rate in the process chamber.
[0044]
[0051] Figure 3B is a cross-sectional side view showing 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 process area 136.
[0045]
[0052] The fins 302 and baffle plates 304 extend to the entire height of the exhaust plenums 312a and 312b, such that the fins 302 and baffle plates 304 extend between the top surface 326 and the bottom surface 327 of the exhaust plenums 312a and 312b. The growth monitor within the fin array 314 is located on the top surface 326.
[0046]
[0053] The exhaust collector 206 is connected to the back end of the exhaust system 178. The exhaust collector 206 includes a top surface 328, a bottom surface 327, and a back side wall 324. A growth monitor 310 immediately 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 positioned on the back side wall 321 of the collector plenum 316. The positioning of the growth monitors 310 allows for accurate measurement of the film growth rate by each growth monitor 310. The measurements from each growth monitor 310 can be mapped to observe differences in growth rates across different locations on the substrate 102.
[0047]
[0054] The conduit opening 306 is positioned through the bottom surface 327 of the collector plenum 316 and opens into the exhaust conduit 323. The exhaust conduit 323 extends downward 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 side wall 321 of the collector plenum 316.
[0048]
[0055] In some embodiments, more or fewer growth monitors 310 can be used within the exhaust system 178. In some embodiments, only growth monitors 310 adjacent to the exhaust outlet openings 308a and 308b are located within the exhaust system 178. In other embodiments, the growth monitors 310 adjacent to the exhaust outlet openings 308a and 308b may be a single growth monitor 310. In yet another embodiment, growth monitors 310 adjacent to the exhaust outlet openings 308a and 308b and growth monitors 310 on the rear side wall 321 of the collector plenum 316 are used.
[0049]
[0056] Figures 4A and 4B show a growth monitor 310 for use in the deposition chamber 100 of Figure 1 according to an embodiment of the present disclosure. The growth monitor 310 is a parametric resonant sensor comprising a shuttle mass 402, an electrostatic actuator 404, an amplitude and / or velocity sensor 406, a plurality of anchors 408, and a plurality of beams 410. The shuttle mass 402 is one or more of silicon-containing material, bulk titanium, and electroplated nickel.
[0050]
[0057] The shuttle mass 402 further includes a first finger set 420 and a third finger set 424. The electrostatic actuator 404 further includes a second finger set 422. In one embodiment, the amplitude and / or velocity sensor 406 is a capacitor sensor. The capacitance sensor 406 further includes a fourth finger set 426. The first to fourth finger sets 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 that can apply voltage to the electrostatic actuator 404. The potential source 412 is further configured to function as (or may include) a ground for connecting to one of a plurality of anchors 408. The plurality of beams 410 are configured to couple the shuttle mass 402 to the anchors 408 such that the anchors 408 secure the shuttle mass 402 to the exhaust collector 206. In one embodiment, the amplitude and / or velocity sensor 406 may be an additional or alternative frequency sensor.
[0051]
[0058] During operation, the first finger set 420 is spaced apart from the second finger set 422, and the third finger set 424 is spaced apart from the fourth finger set 426. In one embodiment shown in Figure 4A, the spacing between the finger sets is in an interdigitated configuration, meaning that the first finger set 420 and the second finger set 422 are interconnected, and the third finger set 424 and the fourth finger set 426 are interconnected. In yet another embodiment, the spacing is in an interdigitated curved secondary comb finger configuration. When the potential source 412 applies a bias to the electrostatic actuator 404, the electrostatic actuator 404 is configured to actuate the shuttle mass 402 at the operating frequency. The input bias actsuate the shuttle mass 402 over a frequency range near the parametric resonance instability frequency. A bias is applied across the first finger set 420 and the second finger set 422 so that the normal forces on both sides of each finger of the finger set cancel each other out. However, the lateral force causes the first finger set 420 to act parallel to the second finger set 422, and thus acts the shuttle mass 402. In one embodiment, the actuation is translational. In another embodiment, the actuation is rotational. In another embodiment shown in Figure 4B, the spaced relationship of the finger sets is a non-interdigit comb-finger configuration. The shuttle mass 402 is fixed in place by anchors 408 via a plurality of beams 410. The plurality of beams 410 are configured to resist the actuation of the shuttle mass 402. When the shuttle mass 402 moves relative to the electrostatic actuator 404 due to the force between the first finger set 420 and the second finger set 422, the plurality of beams 410 act as springs to return the shuttle mass 402 to its original position. The third finger set 424 is configured to move parallel to the fourth finger set 426 as a result of the operation of the shuttle mass 402. The capacitance sensor is configured to measure the change in the parametric resonant instability frequency by measuring the operating amplitude and / or velocity of the shuttle mass 402.The frequency values at which the amplitude increases significantly at unstable frequencies are precisely known. As the mass of the shuttle mass 402 increases, the transition frequency changes. By tracking the transition frequency, the thickness of the material deposited on the growth monitor 310 can be measured, as further described below.
[0052]
[0059] The parametric resonant sensor measures the frequency shift at the resonant stable boundary to monitor the mass change of the shuttle mass 402. The amplitude and / or velocity transition at the resonant stable boundary is very sharp, which allows for the easy detection of small frequency changes and results in high frequency shift resolution. An advantage of the parametric resonant sensor is that the sharpness of the boundary does not depend on the quality factor (Q). Therefore, it can detect very small mass changes not only at atmospheric pressure but also in high-pressure environments.
[0053]
[0060] In contrast, mass sensing devices based on simple harmonic resonance, such as quartz crystal microbalances (QCMs), are limited by their ability to detect small frequency changes, which are described by the quality factor (Q). The minimum detectable mass change using an SHR is directly proportional to the minimum detectable frequency change, which is inversely proportional to the Q factor. Therefore, in monitoring applications of epitaxial mass deposition where typical pressures range from 5 Torr to 760 Torr, the minimum detectable mass change becomes significantly higher. This limits the range of processes in which QCM-based sensing can be used for monitoring. However, the parametric resonant sensors of this disclosure have 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.
[0054]
[0061] As exhaust gas flows through the exhaust system 178, unreacted precursor gases present in the reaction byproducts deposit on the growth monitor 310. The shuttle mass 402 is activated using a voltage applied by the potential source 412. A periodic sweep is performed over a small frequency range near the parametric instability region. Beyond the instability region, the vibration amplitude changes abruptly. In one embodiment, the capacitance sensor measures the vibration amplitude when the capacitance between the shuttle mass 402 and the capacitance sensor changes due to a shift in the position of the third finger set 424 relative to the fourth finger set 426. The frequency at which this occurs is recorded and compared to the value from the last frequency sweep. The change in frequency is related to the change in mass. With prior calibration, the change in mass due to condensation on the shuttle mass 402 is related to the thickness deposited on the substrate 102. This enables in-situ and real-time measurement of the deposit on the substrate 102.
[0055]
[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 mass 402 to characterize the operating amplitude and / or velocity of the shuttle mass 402. The vibration amplitude is measured using the laser Doppler vibrometer. In one embodiment, the laser Doppler vibrometer amplitude and / or velocity sensor has a built-in 45-degree mirror. The mirror can be cut by a focused ion beam after device fabrication. Laser light is directed at the mirror and reflected onto the shuttle mass 402. The reflected light from the shuttle mass 402 is measured to characterize the operating amplitude and / or velocity of the shuttle mass 402. As the mass of the shuttle mass 402 increases due to exhaust gas deposition, 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 focusing on the frequency at which the transition to large-amplitude vibration begins. By tracking this time-dependent change in the parametric resonance frequency due to the mass increase of the shuttle mass 402, the thickness of the material deposited on the growth monitor 310 can be determined. Prior calibration indicates that the change in mass due to condensation on the shuttle mass is related to the thickness deposited on the substrate 102.
[0056]
[0063] Since the growth monitor 310 is configured to be located within the deposition chamber 100, it is affected by reactive process chemicals in the exhaust system 178. The protective coating, as well as the materials of the anchors 408, the multiple beams 410, and the shuttle mass 402, affect the reactivity of the growth monitor 310 with the process chemicals in the deposition chamber 100. Therefore, a material composition is selected that reduces the reactivity of the growth monitor 310 with the process chemicals in the deposition chamber 100 while enabling accurate film thickness measurement on the growth monitor 310.
[0057]
[0064] The protective coating is formed from one of the silicon oxides, such as alumina (Al2O3) or silicon dioxide (SiO2). The protective coating is formed from a material that does not degrade when exposed to epitaxial deposition process conditions or process gases. The protective coating may be a cover lens or a coating applied to the shuttle mass 402. The protective coating has a thickness of less than about 10 μm, for example, about 1 nm to about 10 nm, for example, about 1 nm to about 5 nm. The thin thickness allows the growth monitor 310 to be protected without significantly attenuating the operation of the shuttle mass 402.
[0058]
[0065] Figure 5 is a schematic control diagram 500 for use within the deposition chamber 100 of Figure 1 according to an embodiment of the present disclosure. The controller 120 is configured to receive data or inputs from each growth monitor 310 as sensor readings 502. The controller 120 has or communicates 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 the gas flow and heating within the deposition chamber 100 during the deposition process. The controller 120 is further configured to store readings and calculated values 504.
[0059]
[0066] The readings and calculated values 504 include not only the previous sensor reading 502 but also any other previous sensor readings within the deposition chamber 100. The readings and calculated values 504 further include stored calculated values from after the sensor reading 502 has been measured by the controller 120 and run through the system model 506. Thus, the controller 120 is configured to retrieve the stored readings and calculated values 504 and to save them for future use. By maintaining previous readings and calculated values, the controller 120 can adjust the system model 506 over time to reflect a more accurate version of the deposition chamber 100.
[0060]
[0067] In embodiments described herein, the controller 120 includes a programmable central processing unit (CPU) operating with memory and mass storage, an input control unit, and a display device (not shown). The controller 120 monitors the flow of precursor, process gas, and purge gas. Support circuits are coupled to the CPU to assist the processor in a conventional manner. In some embodiments, the controller 120 includes multiple controllers 120 such that stored read and calculated values 504 and 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 all stored read and calculated values 504 are stored within the controller 120.
[0061]
[0068] The controller 120 is configured to control heating and gas flow within the deposition chamber 100 by controlling the configuration of the ramp and gas flow control device 508. The ramp and gas flow control device 508 includes an upper ramp 141, a lower ramp 143, a process gas source 151, a purge gas source 162, and an exhaust pump 157. The controller 120 can also control the operating assembly 121 within the deposition chamber 100.
[0062]
[0069] The controller 120 is configured to adjust the output to the ramp and gas flow control device 508, respectively, based on sensor readings 502, system model 506, and stored readings and calculated values 504. The controller 120 includes built-in software and correction algorithms for calibrating the frequency shift of the growth monitor 310 to the film thickness on the substrate 102. To provide a reference for the film thickness growth rate measured using the growth monitor 310, the film thickness on the substrate 102 may be measured when the substrate 102 leaves the deposition chamber or during process steps. The controller 120 may include machine learning algorithms, and regression or clustering techniques may be used. The algorithms may be unsupervised or supervised.
[0063]
[0070] Figure 6 shows a method 600 for adjusting process conditions within the deposition chamber 100 of Figure 1 according to an embodiment of the present disclosure. Method 600 improves film thickness uniformity and properties across the entire substrate 102 using a growth monitor 310 within the deposition chamber 100 and a controller 120 as described herein.
[0064]
[0071] During method 600, in step 602, a first substrate is processed in a processing chamber. The first substrate may be substrate 102, and the processing chamber is a deposition chamber 100. Processing the first substrate in step 602 includes performing a deposition process, such as an epitaxial deposition process, on the first substrate. The deposition process includes growing a film on the first substrate and heating the substrate using an upper lamp 141 and a lower lamp 143. Gases are introduced into the process area 136 from a process gas inlet 114 and a purge gas inlet 164 before being removed through an exhaust gas outlet 116.
[0065]
[0072] While the first substrate is being processed in the processing chamber, the film thickness growth on the monitor is measured using the growth monitor 310 during another step 604. The measurement of film thickness growth on the growth monitor 310 is performed as a rolling step. A controller, such as the controller 120, is configured to receive input from the combination of growth monitors 310 described with respect to Figures 3A and 3B. This input is used to estimate the film growth on the first substrate. Once the first substrate has finished processing in the processing chamber, the film thickness may be measured during another step 606 using one or more other non-contact sensors in the processing chamber or an adjacent chamber. The measurement of film growth on the first substrate during step 606 is performed in a non-destructive manner, such as using one or more non-contact sensors. The non-contact sensor may be a laser thickness gauge that can perform multiple individual measurements across the entire surface of the first substrate or scan the length of the first substrate.
[0066]
[0073] Non-contact sensors used in process 606 are not necessarily used for measuring film thickness during substrate processing because radiation from process gases and heat sources interferes with the sensor readings, reducing reading sensitivity and accuracy. Therefore, the growth monitor 310 allows for adjustment of process conditions such as heating and gas flow while the first substrate is being processed. The measurement values obtained using the non-contact sensors can be used to update or confirm the correlation between film formation on one or more growth monitors 310 and film formation on the substrate. Thus, measurement using non-contact sensors is optional and can be omitted.
[0067]
[0074] By measuring film growth on the first substrate, it becomes possible to calculate the growth rate on the first substrate during another step 608. Calculating the growth rate on the first substrate during step 608 verifies the accuracy of the model used in the controller, allowing the processing chamber model to be adjusted during another step 610 to achieve a predetermined film growth on the substrate during processing. Adjusting the processing chamber model during step 610 allows for better use of the growth monitor 310 in specific processes. Once the model is adjusted, processing of another substrate, such as a second substrate, is performed, and steps 602-610 are repeated. Step 602 can be looped to continuously adjust the accuracy of the processing chamber model 610 and improve the film thickness growth results. If preventative maintenance is performed on the processing chamber, the processing chamber model can be reset or adjusted, and method 600 can be restarted. Thus, the film thickness results are continuously improved across each substrate. This further enables accurate film thickness and overcomes changes due to film accumulation on the surface within the process area, as well as changes in processing chamber characteristics due to lamp aging.
[0068]
[0075] Figure 7 shows a method 700 using the growth monitor 310 according to an embodiment. In step 702, the shuttle mass 402 is actuated by an electrostatic force from an electrostatic actuator. In step 704, the frequency range near the parametric resonant instability boundary of the shuttle mass 402 is swept. In step 706, exhaust gas is deposited on the shuttle mass 402 to rapidly change the vibration amplitude of the shuttle mass 402. The frequency value is recorded by the controller 120. In step 708, the current value of the instability frequency is compared with the previous value of the instability frequency. The difference in values corresponds to the change in mass of the shuttle mass 402 due to the deposition of exhaust gas. The correspondence between the instability frequencies (and the changes between them) and the associated mass can be empirically determined and stored in a data table accessible by the controller. In step 710, the controller 120 outputs a thickness value to the user. The thickness value is calculated using a previous calibration that correlates the change in mass of the shuttle mass 402 with the increase in thickness on the substrate 102. In step 712, the frequency range near the parametric resonance boundary is periodically swept to continuously monitor the thickness change on the shuttle mass 402.
[0069]
[0076] While the foregoing applies to embodiments of the present disclosure, it is possible to devise other further embodiments of the present disclosure without departing from its basic scope as defined by the following claims.
Claims
1. An exhaust system for substrate processing, The first exhaust plenum, A first exhaust inlet opening is fluidly connected to the first exhaust plenum, A plurality of first fins arranged within the first exhaust plenum adjacent to the first exhaust inlet opening, A first exhaust outlet opening is fluidly connected to the first exhaust plenum, A first baffle plate is positioned adjacent to the first exhaust outlet opening and configured to narrow the width of the first exhaust plenum, At least one growth monitor positioned downstream of the first baffle plate and configured to measure the thickness of material deposited on the growth monitor, the growth monitor being a parametric resonant sensor and An exhaust system equipped with this feature.
2. The parametric resonant sensor is Shuttle Mass and An electrostatic actuator configured to operate the shuttle mass at the operating frequency, An amplitude and / or velocity sensor configured to measure changes in the operating amplitude and / or velocity of the shuttle mass, Multiple anchors, Multiple beams, configured to connect the multiple anchors to the shuttle mass, and resisting the operation of the shuttle mass, and The exhaust system according to claim 1, comprising:
3. The exhaust system according to claim 2, wherein the shuttle mass comprises one or more of a silicon-containing material, bulk titanium, and electroplated nickel.
4. The exhaust system according to claim 2, wherein the shuttle mass further includes a first set of fingers, and the electrostatic actuator further includes a second set of fingers, wherein the first set of fingers is configured to operate in parallel with the second set of fingers.
5. The exhaust system according to claim 4, wherein the shuttle mass further includes a third set of fingers, the amplitude and / or velocity sensors are capacitance sensors, the capacitance sensors further include a fourth set of fingers, and the third set of fingers is configured to move parallel to the fourth set of fingers as a result of the operation of the shuttle mass.
6. The exhaust system according to claim 5, wherein the capacitance sensor measures the change in parametric resonance frequency when the mass of the shuttle mass increases and determines the thickness of the material deposited on the growth monitor.
7. The exhaust system according to claim 4, wherein the amplitude and / or velocity sensor is a laser Doppler vibrometer configured to measure light reflected from the shuttle mass in order to track changes in the resonant frequency of the shuttle mass.
8. The exhaust system according to claim 7, wherein the laser Doppler vibrometer measures the change in operating amplitude and / or velocity when the mass of the shuttle mass increases, and determines the thickness of the material deposited on the growth monitor.
9. A processing system suitable for semiconductor substrate processing, The chamber body forming the process area, A substrate support disposed within the process area of the chamber body, An upper window positioned above the substrate support, A lower window positioned below the substrate support, wherein the upper window and the lower window further define the process region, An injector is positioned to penetrate one side of the chamber body and configured to introduce process gas into the process area, An exhaust system comprising at least one growth monitor positioned through a second side of the chamber body opposite the injector and configured to measure the thickness of material deposited on the growth monitor, wherein the growth monitor is a parametric resonant sensor, and A processing system equipped with the following features.
10. The parametric resonant sensor is Shuttle Mass and An electrostatic actuator configured to operate the shuttle mass at the operating frequency, An amplitude and / or velocity sensor configured to measure changes in the operation of the shuttle mass, Multiple anchors configured to be connected to the exhaust system, Multiple beams, configured to connect the multiple anchors to the shuttle mass, and resisting the operation of the shuttle mass, and The processing system according to claim 9, including the following:
11. The processing system according to claim 10, wherein the shuttle mass comprises one or more of a silicon-containing material, bulk titanium, and electroplated nickel.
12. The processing system according to claim 10, wherein the shuttle mass further includes a protective coating, the protective coating being one of alumina or silicon dioxide.
13. The processing system according to claim 9, wherein the at least one growth monitor communicates 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 in response to the determined growth rate.
14. The processing system according to claim 10, further comprising a controller which compares the measured growth rate on a growth monitor, a chamber heat model, a chamber flow rate model, and a previous monitor measurement to determine an adjustment for at least one of the process gas flow rate, heating energy level, or exhaust flow rate.
15. A process system controller, which, when executed by a processor, controls the system. Processing a substrate in a processing chamber by flowing process gas into a process area from a process gas inlet, depositing the gas on the substrate, and exhausting the process gas through an exhaust system, wherein the exhaust system further includes a growth monitor, and the growth monitor includes a parametric resonant sensor. Depositing the process gas on the growth monitor, Measuring film growth on the aforementioned growth monitor, To calculate the film growth rate on the aforementioned substrate, Adjusting the processing chamber parameters and A controller that stores commands to perform an action.
16. The controller according to claim 15, further comprising the controller acting on a shuttle mass with respect to amplitude and / or velocity sensors.
17. The controller according to claim 16, further comprising the controller causing the system to sweep over a frequency range near the parametric resonant instability boundary of the shuttle mass in a first time interval and a second time interval in order to determine the parametric resonant instability frequency of the shuttle mass.
18. The controller according to claim 17, further comprising the controller causing the system to compare the value of the parametric resonant instability frequency of the shuttle mass in a first time interval with the value of the parametric resonant instability frequency of the shuttle mass in a second time interval in order to output film growth on a substrate using processing chamber parameters.
19. The controller according to claim 18, which adjusts at least one of the process gas flow rate, heating energy level, or exhaust flow rate in response to a calculated film growth rate on a substrate.
20. The controller according to claim 19, which compares the growth rate on a measured growth monitor, a chamber heat model, a chamber flow rate model, and a previous monitor measurement to determine an adjustment for at least one of the process gas flow rate, heating energy level, or exhaust flow rate.