Substrate thickness measurement device, substrate processing system, and substrate thickness measurement method

Abstract

This invention aims to provide a technique for improving the accuracy of substrate thickness measurement. According to the present invention, a substrate thickness measuring apparatus includes: a substrate holding part, a thickness measuring part, a housing, a temperature measuring part, and a thickness correction part. The substrate holding part holds the substrate. The thickness measuring part measures the thickness of the substrate held by the substrate holding part. The housing houses at least a portion of the substrate holding part and the thickness measuring part. The thickness correction part corrects the thickness measured by the thickness measuring part. The thickness correction part performs the following steps: calculating the product of the thickness measured by the thickness measuring part and a preset correction coefficient to obtain the corrected thickness; and changing the setting of the correction coefficient if the temperature measured by the temperature measuring part exceeds a preset allowable range.

Description

Technical Field

[0001] This invention relates to a substrate thickness measuring device, a substrate processing system, and a substrate thickness measuring method. Prior Technology

[0002] The film thickness measuring device described in Patent Document 1 includes: a film thickness measuring unit for measuring the film thickness of a film layer formed on the surface of a substrate; a humidity measuring unit for measuring the humidity around the film thickness measuring unit; a storage unit for storing information about the relationship between humidity and film thickness; and a correction unit for calculating a first correction amount from the humidity measured by the humidity measuring unit and the information stored in the storage unit to correct the measured value of film thickness, and then correcting the measured value of film thickness measured by the film thickness measuring unit using the calculated first correction amount. [Known Technical Documents] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-062003 Summary of the Invention

[0004] [The problem the invention aims to solve]

[0005] One aspect of this invention provides a technique to address temperature variations in a substrate and improve the accuracy of substrate thickness measurement. [Technical means to solve the problem]

[0006] One aspect of the present invention provides a substrate thickness measuring apparatus comprising: a substrate holding portion, a thickness measuring portion, a housing, a temperature measuring portion, and a thickness correction portion. The substrate holding portion holds a substrate. The thickness measuring portion measures the thickness of the substrate held by the substrate holding portion. The housing houses at least a portion of the substrate holding portion and the thickness measuring portion. The thickness correction portion corrects the thickness measured by the thickness measuring portion. The thickness correction portion performs the following steps: calculating the product of the thickness measured by the thickness measuring portion and a preset correction coefficient to obtain the corrected thickness; and changing the setting of the correction coefficient if the temperature measured by the temperature measuring portion exceeds a preset allowable range. [Effects of the Invention]

[0007] According to one embodiment of the present invention, the temperature variation of the substrate can be addressed, thereby improving the accuracy of substrate thickness measurement. Simple Explanation of the Diagram

[0008] [Figure 1] Figure 1 is a top view showing an embodiment of a substrate processing system. [Figure 2] Figure 2 is a cross-sectional view along line II-II of Figure 1. [Figure 3] Figure 3 is a flowchart showing a substrate processing method in one embodiment. [Figure 4] Figure 4 is a top view of an example of a substrate thickness measuring device, and a cross-sectional view along line IV-IV in Figure 5. [Figure 5] Figure 5 is a cross-sectional view along line VV of Figure 4. [Figure 6] Figure 6 is a side view showing an example of the thickness measuring section and the temperature control section. [Figure 7] Figure 7 is an illustration of one of the components of a control device using function blocks. [Figure 8] Figure 8 is a flowchart showing one example of setting the correction factor. [Figure 9] Figure 9 is a flowchart of one example of the correction of substrate thickness. [Figure 10] Figure 10 is an illustration showing an example of the variation in thickness measurement values ​​relative to changes in humidity. [Figure 11] Figure 11 is an illustration of an example of the variation in thickness measurement values ​​relative to the change in the distance between the probe and the substrate. [Figure 12] Figure 12 is an illustration of an example of the variation in light intensity detected by the photodetector and the variation in thickness measurement value relative to the change in the distance between the probe and the substrate. Implementation

[0009] The following description refers to embodiments of the present invention with reference to the accompanying drawings. Furthermore, in the drawings, identical or corresponding components may be labeled with the same symbols and their descriptions omitted. In this specification, the X-axis, Y-axis, and Z-axis are mutually perpendicular directions. The X-axis and Y-axis are horizontal directions, and the Z-axis is a vertical direction.

[0010] First, referring to Figures 1 and 2, a substrate processing system 1 according to one embodiment will be described. The substrate processing system 1 grinds a substrate W. In this specification, grinding includes polishing. The substrate processing system 1 includes: a loading / unloading block 2, a cleaning block 3, and a grinding block 5. The loading / unloading block 2, the cleaning block 3, and the grinding block 5 are arranged in this order from the negative X-axis side to the positive X-axis side.

[0011] The loading / unloading section 2 includes a placement section 21 for holding a wafer cassette C that houses the substrates W. The wafer cassette C horizontally houses a plurality of substrates W arranged at intervals in the vertical direction. The substrates W include semiconductor substrates such as silicon wafers or compound semiconductor wafers, or glass substrates. The substrates W may further include a component layer formed on the surface of the semiconductor substrate or glass substrate. The component layer includes electronic circuitry. Furthermore, the substrates W may also be overlapping substrates bonded together with the plurality of substrates.

[0012] As shown in Figures 1 and 2, the cleaning block 3 includes, for example, cleaning devices 31A and 31B for cleaning the polished substrate W; etching devices 32A and 32B for etching the cleaned substrate W; a substrate thickness measuring device 33 for measuring the thickness of the etched substrate W; a flipping device 34 for flipping the substrate W; a transfer device 35 for temporarily storing the substrate W; and a storage device 61 for storing the calibration substrate (described later). The calibration substrate is used to correct the thickness of the substrate W measured by the substrate thickness measuring device 33. Furthermore, the cleaning block 3 includes a first transport area 36 and a second transport area 37. A first transport device 38 is provided in the first transport area 36; a second transport device 39 is provided in the second transport area 37. The first transport device 38 transports the substrate W between the cleaning devices 31A and 31B and the polishing block 5. The second transport device 39 transports the substrate W between the wafer cassette C on the mounting section 21 and the cleaning block 3.

[0013] The cleaning devices 31A and 31B, the transfer device 35, the storage device 61, and the substrate thickness measuring device 33 are stacked vertically and positioned within the area surrounded by the first transport area 36, ​​the second transport area 37, and the polishing block 5. The cleaning devices 31A and 31B, the transfer device 35, the storage device 61, and the substrate thickness measuring device 33 are stacked in this order from top to bottom. However, the order is not particularly limited. Furthermore, the etching devices 32A and 32B are stacked vertically and positioned adjacent to the first transport area 36 and the second transport area 37.

[0014] The first transport device 38 transports substrate W in the first transport area 36. That is, the first transport device 38 transports substrate W among a plurality of devices arranged beside the first transport area 36. The first transport device 38 has a plurality of independently movable transfer arms. Each transfer arm can move horizontally (in both the X and Y axes) and vertically, and can rotate about a vertical axis. Each transfer arm holds substrate W from below. The number of transfer arms is not particularly limited.

[0015] Similarly, the second transport device 39 transports the substrate W in the second transport area 37. That is, the second transport device 39 transports the substrate W among a plurality of devices arranged beside the second transport area 37. The second transport device 39 has a plurality of independently movable transfer arms. Each transfer arm can move horizontally (in both the X and Y axes) and vertically, and can rotate about a vertical axis. Each transfer arm holds the substrate W from below.

[0016] As shown in Figure 1, the grinding block 5 includes, for example, four holding parts 52A, 52B, 52C, and 52D for holding the substrate W; two tool driving parts 53A and 53B for driving the grinding tool D of the substrate W; and an internal transport part 54 for transporting the substrate W within the grinding block 5. The grinding block 5 may further include a rotary table 51 that rotates around a rotation center line R1. The four holding parts 52A, 52B, 52C, and 52D are spaced apart around the rotation center line R1 and rotate together with the rotary table 51. Furthermore, the four holding parts 52A, 52B, 52C, and 52D rotate around their respective rotation center lines R2.

[0017] Two holding parts 52A and 52C are symmetrically arranged around the rotation center line R1 of the rotary table 51. Each holding part 52A and 52C moves between the first loading / unloading position A3, where the substrate W is loaded and unloaded by the internal transport part 54, and the first grinding position A1, where the substrate W is ground by a tool drive part 53A. The two holding parts 52A and 52C move between the first loading / unloading position A3 and the first grinding position A1 every time the rotary table 51 rotates 180°.

[0018] The other two holding parts 52B and 52D are symmetrically arranged around the rotation center line R1 of the rotary table 51. Each holding part 52B and 52D moves between the second loading / unloading position A0, where the substrate W is loaded and unloaded by the internal transport part 54, and the second grinding position A2, where the substrate W is ground by another tool drive part 53B. The other two holding parts 52B and 52D move between the second loading / unloading position A0 and the second grinding position A2 every time the rotary table 51 rotates 180°.

[0019] When viewed from above, the first loading / unloading position A3, the second loading / unloading position A0, the first grinding position A1, and the second grinding position A2 are arranged counterclockwise in this order. In this case, when viewed from above, the retaining parts 52A, 52B, 52C, and 52D are arranged counterclockwise at 90° intervals.

[0020] Alternatively, the positions of the first loading / unloading position A3 and the second loading / unloading position A0 can be reversed, and the positions of the first grinding position A1 and the second grinding position A2 can also be reversed. In other words, when viewed from above, the first loading / unloading position A3, the second loading / unloading position A0, the first grinding position A1, and the second grinding position A2 can be arranged clockwise in this order. In this case, when viewed from above, the holding parts 52A, 52B, 52C, and 52D are arranged clockwise at 90° intervals.

[0021] However, the number of holding parts is not limited to four. The number of tool driving parts is also not limited to two. Furthermore, the rotary table 51 may not be necessary. For example, a slide table may be provided instead of the rotary table 51.

[0022] As shown in FIG2, the grinding block 5 includes temporary storage sections 57A, 57B, and 57C for temporarily storing the substrate W. The temporary storage sections 57A, 57B, and 57C deliver the substrate W between the internal transport section 54 and the first transport device 38 of the cleaning block 3. The internal transport section 54 receives the substrate W delivered to the temporary storage sections 57A and 57B by the first transport device 38 from the temporary storage sections 57A and 57B. Furthermore, the first transport device 38 receives the substrate W delivered to the temporary storage section 57C by the internal transport section 54 from the temporary storage section 57C.

[0023] Temporary placement sections 57A and 57B also serve as alignment sections for adjusting the center position of the substrate W. The alignment sections use guides and the like to align the center of the substrate W to the desired position. Then, by using the internal transport section 54 to transport the substrate W to a pre-set loading position, and then handing the substrate W over to the holding sections 52A, 52B, 52C, and 52D at that loading position, the centers of the holding sections 52A, 52B, 52C, and 52D will align with the center of the substrate W when viewed from above.

[0024] Furthermore, the alignment unit can also detect the center position of the substrate W using an optical system or similar means. In this case, the control unit 9, by correcting the preset loading position based on the detection results of the alignment unit, can ensure that the centers of each holding part 52A, 52B, 52C, and 52D are aligned with the center of the substrate W when viewed from above. Moreover, the alignment unit can also detect the crystal orientation of the substrate W using an optical system or similar means; specifically, it can also detect notches or orientation planes that display the crystal orientation of the substrate W. By rotating a coordinate system that rotates together with each holding part 52A, 52B, 52C, and 52D, the crystal orientation of the substrate W can be aligned with the desired orientation.

[0025] Temporary placement portions 57A and 57B can be stacked vertically to reduce the installation area of ​​the substrate processing system 1. The stacking order is not limited to the order shown in the figure and can also be reversed. When temporary placement portions 57A and 57B also serve as alignment portions, a guide member can be included to replace the optical system. This is because, compared to the case where an optical system is included, the Z-axis dimension of temporary placement portions 57A and 57B can be reduced when a guide member is included in the temporary placement portions 57A and 57B.

[0026] Temporary placement units 57B and 57C are positioned above the transport paths TR1 and TR2 of the internal transport unit 54 that transport the substrate W between the temporary placement units 57B and 57C and the holding unit (e.g., holding unit 52D) located at the second transport-in / transport position A0. When viewed from above, the temporary placement units 57B and 57C overlap with the transport paths TR1 and TR2.

[0027] The grinding block 5 may also include a flipping section 58 of the flipped substrate W. The flipping section 58 is disposed above the transport paths TR1 and TR2. The flipping section 58 and the temporary placement sections 57A, 57B, and 57C are stacked in the vertical direction. For example, the flipping section 58, the temporary placement section 57C, the temporary placement section 57B, and the temporary placement section 57A are stacked in this order from top to bottom. However, the stacking order is not particularly limited.

[0028] As shown in FIG1, the substrate processing system 1 further includes a control unit 9. The control unit 9, such as a computer, includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as memory. The storage medium 92 stores programs that control various processes executed in the substrate processing system 1. The control unit 9 controls the operation of the substrate processing system 1 by causing the CPU 91 to execute the programs stored in the storage medium 92.

[0029] Next, referring to FIG3, a substrate processing method implemented by substrate processing system 1 will be described. The substrate processing method includes, for example, steps S101 to S111 shown in FIG3. Steps S101 to S111 are implemented under the control of control unit 9. Furthermore, the substrate processing method may not include all the steps shown in FIG3, or it may include steps not shown in FIG3.

[0030] First, the second transport device 39 removes the substrate W from the wafer cassette C and transports it to the transfer device 35. Next, the first transport device 38 receives the substrate W from the transfer device 35 and transports it to the temporary placement section 57A of the polishing block 5. The substrate W has a first main surface and a second main surface facing opposite directions, and is transported with the first main surface facing upwards.

[0031] Next, the temporary placement unit 57A adjusts the center position of the substrate W (step S101). The temporary placement unit 57A can also detect the center position of the substrate W. Furthermore, in addition to detecting the center position of the substrate W, the temporary placement unit 57A can also detect the crystal orientation of the substrate W. Specifically, it can detect the notch or orientation plane of the crystal orientation of the display substrate W.

[0032] Next, the internal transport unit 54 receives the substrate W from the temporary placement unit 57A and transports it to the holding unit (e.g., holding unit 52C) located at the first loading / unloading position A3. The substrate W is placed on the holding unit 52C with its first main surface facing upwards. At this time, the center of the substrate W is aligned with the rotation center line R2 of the holding unit 52C. Afterwards, the rotary table 51 is rotated 180°, and the holding unit 52C is moved from the first loading / unloading position A3 to the first grinding position A1.

[0033] Next, the tool drive unit 53A drives the polishing tool D to polish the first main surface of the substrate W (step S102). After that, the rotary table 51 is rotated 180°, and the holding part 52C is moved from the first polishing position A1 to the first loading and unloading position A3. Then, the internal transport unit 54 receives the substrate W from the holding part 52C located at the first loading and unloading position A3, and then transports it to the flipping part 58.

[0034] Next, the flipping unit 58 flips the substrate W (step S103). The substrate W is flipped up and down, so that the first main surface faces down and the second main surface faces up. After that, the first transport device 38 of the cleaning block 3 receives the substrate W from the flipping unit 58 and then transports it to the cleaning device 31A.

[0035] Next, the cleaning device 31A cleans the first main surface of the substrate W (step S104). The cleaning device 31A removes fine dust particles such as grinding debris. The cleaning device 31A, for example, brushes and cleans the substrate W. The cleaning device 31A can clean not only the first main surface of the substrate W but also the second main surface. After the substrate W dries, the first transport device 38 receives the substrate W from the cleaning device 31A and then transports it to the temporary storage section 57B of the grinding area 5.

[0036] Next, the temporary placement unit 57B adjusts the center position of the substrate W (step S105). The temporary placement unit 57B can also detect the center position of the substrate W. Furthermore, in addition to detecting the center position of the substrate W, the temporary placement unit 57B can also detect the crystal orientation of the substrate W. Specifically, it can detect the notch or orientation plane of the crystal orientation of the display substrate W.

[0037] Next, the internal transport unit 54 receives the substrate W from the temporary placement unit 57B and transports it to the holding unit (e.g., holding unit 52D) located at the second transport-in / transfer position A0. The substrate W is placed on the holding unit 52D with its second main surface facing upwards. At this time, the center of the substrate W is aligned with the rotation center line R2 of the holding unit 52D. Afterwards, the rotary table 51 is rotated 180°, and the holding unit 52D is moved from the second transport-in / transfer position A0 to the second grinding position A2.

[0038] Next, the tool drive unit 53B drives the polishing tool D to polish the second main surface of the substrate W (step S106). Afterwards, the rotary table 51 is rotated 180°, and the holding part 52D is moved from the second polishing position A2 to the second loading / unloading position A0. Then, the internal transport unit 54 receives the substrate W from the holding part 52D located at the second loading / unloading position A0 and transports it to the temporary storage unit 57C. Afterwards, the first transport device 38 of the cleaning block 3 receives the substrate W from the temporary storage unit 57C and transports it to the cleaning device 31B.

[0039] Next, the cleaning device 31B cleans the second main surface of the substrate W (step S107). The cleaning device 31B removes fine dust particles such as grinding debris. The cleaning device 31B, for example, brushes and cleans the substrate W. The cleaning device 31B can clean not only the second main surface of the substrate W, but also the first main surface. After the substrate W dries, the second transport device 39 receives the substrate W from the cleaning device 31B and then transports it to the etching device 32B.

[0040] Next, the etching apparatus 32B etches the second main surface of the substrate W (step S108). The etching apparatus 32B can remove the grinding scratches on the second main surface. After the substrate W dries, the second transport device 39 receives the substrate W from the etching apparatus 32B and then transports it to the flipping device 34.

[0041] Next, the flipping device 34 flips the substrate W (step S109). The substrate W is flipped up and down, so that the first main surface faces upward and the second main surface faces downward. After that, the second transport device 39 receives the substrate W from the flipping device 34 and then transports it to the etching device 32A.

[0042] Next, the etching apparatus 32A etches the first main surface of the substrate W (step S110). The etching apparatus 32A can remove the grinding scratches on the first main surface. After the substrate W dries, the second transport device 39 receives the substrate W from the etching apparatus 32A and then transports it to the substrate thickness measuring device 33.

[0043] Next, the substrate thickness measuring device 33 measures the thickness of the etched substrate W (step S111). For example, it checks whether the thickness of the substrate W and the total thickness variation (TTV) are within a preset allowable range. Afterward, the second transport device 39 receives the substrate W from the substrate thickness measuring device 33 and places the received substrate W into the wafer cassette C. Then, this round of processing ends.

[0044] The illustration in Figure 3 focuses on a single substrate W and describes the substrate processing method. To increase throughput, the substrate processing system 1 can perform multiple processing operations simultaneously at multiple locations. For example, the substrate processing system 1 simultaneously grinds the substrate W at both the first grinding position A1 and the second grinding position A2. During this period, the substrate processing system 1 performs the following actions at the first loading / unloading position A3 and the second loading / unloading position A0, respectively, in the following sequence: spray cleaning of the substrate W, measurement of the thickness distribution of the substrate W, unloading of the substrate W, cleaning of the substrate adsorption surface (top surface) of the holding portion, and loading of the substrate W, etc.

[0045] Then, the substrate processing system 1 rotates the rotary table 51 180°. Next, the substrate processing system 1 simultaneously grinds the substrate W again at the first grinding position A1 and the second grinding position A2. During this period, the substrate processing system 1 performs the following actions again at the first loading and unloading position A3 and the second loading and unloading position A0, respectively, in the following order: spray cleaning of the substrate W, measurement of the thickness distribution of the substrate W, unloading of the substrate W, cleaning of the substrate adsorption surface (top surface) of the holding part, and loading of the substrate W, etc.

[0046] Next, referring to Figures 4 to 6, an embodiment of the substrate thickness measuring device 33 will be described. The substrate thickness measuring device 33 includes, for example: a housing 100, a substrate holding part 110, a rotating part 120, a moving part 130, a thickness measuring part 140, an alignment part 150, a temperature measuring part 160, a humidity measuring part 161, an exhaust part 170, an inner cover 180, and a control part 190. Furthermore, the control part 190 may also be a part of the control part 9.

[0047] The housing 100 is, for example, a rectangular box when viewed from a planar perspective. The housing 100 may house, for example, at least a portion of the following: a substrate holding part 110, a rotating part 120, a moving part 130, a thickness measuring part 140 (e.g., probe 141 described later), an alignment part 150, a temperature measuring part 160, a humidity measuring part 161, at least a portion of an exhaust part 170 (e.g., exhaust duct 171 described later), and an inner cover 180.

[0048] An inlet / outlet 101 is formed on the side of the housing 100 facing the second transport area 37. The substrate W and the calibration substrate WA are transported in and out through the inlet / outlet 101. Alternatively, the inlet / outlet 101 may not be equipped with an opening / closing gate, and may be normally open. This allows a stable airflow to flow from the second transport area 37 into the housing 100 through the inlet / outlet 101, thus maintaining a stable temperature inside the housing 100.

[0049] The substrate holding portion 110, as shown in FIG. 5, holds the substrate W inside the housing 100. The substrate holding portion 110 may also hold a calibration substrate WA instead of the substrate W. The calibration substrate WA is used to calibrate the thickness of the substrate W measured by the thickness measuring unit 140. The diameter of the substrate holding portion 110 is, for example, less than half the diameter of the substrate W. The substrate W is held horizontally.

[0050] The rotating part 120 rotates the substrate holding part 110 around a vertical rotation axis 121. The rotating part 120 includes a motor 122. The motor 122 is, for example, a stepper motor. The stepper motor has a plurality of coils around a rotation center line, and rotates the substrate holding part 110 by sequentially supplying current to the plurality of coils. When the rotation of the substrate holding part 110 stops, the stepper motor continuously supplies current to specific coils.

[0051] The moving part 130 moves the substrate holding part 110 in a horizontal direction (e.g., the Y-axis direction) orthogonal to the rotation axis 121. As shown in FIG. 4, the moving part 130 includes, for example, a motor 131 and a ball screw 132 that converts the rotational motion of the motor 131 into linear motion of the substrate holding part 110. The moving part 130 has a guide rail 133 extending in the Y-axis direction and a slider 134 that moves along the guide rail 133. A rotating part 120 is fixed to the slider 134. The moving part 130 moves the substrate holding part 110 by moving the rotating part 120 together with the slider 134.

[0052] The thickness measuring unit 140 measures the thickness of the substrate W held by the substrate holding unit 110. The thickness measuring unit 140 can also be used to measure the radial thickness variation of the substrate W. For example, there are three thickness measuring points: the center of the substrate W, the periphery of the substrate W, and the midpoint between the center and the periphery of the substrate W. The thickness measuring points can be moved radially by the moving unit 130. Furthermore, the thickness measuring points can be moved circumferentially by the rotating unit 120. The thickness measuring unit 140 can also be used to measure the circumferential thickness variation of the substrate W. Alternatively, the thickness measuring points can be moved by moving or rotating the probe 141 of the thickness measuring unit 140, instead of the substrate holding unit 110.

[0053] The thickness measuring unit 140 can be a contact type or a non-contact type, but a non-contact type is preferred. For example, the thickness measuring unit 140 is a beam splitter interferometer, which causes interference between the light reflected from the top surface of the substrate W and the light reflected from the bottom surface of the substrate W, and then analyzes the waveform of the interference wave to measure the thickness of the substrate W. The thickness measuring unit 140 transmits the measured data to the control unit 190.

[0054] The thickness measuring unit 140, as shown in FIG. 6, includes: a probe 141, a light source 143, a photodetector 145, and a housing 146. The probe 141 irradiates light onto the substrate W while simultaneously receiving light reflected from the substrate W. The light source 143 is connected to the probe 141 via an optical fiber 142. The photodetector 145 is connected to the probe 141 via an optical fiber 144. The housing 146 houses the light source 143 and the photodetector 145. The thickness measuring unit 140 includes a calculation unit 1401, which calculates the thickness of the substrate W by analyzing the waveform of the light detected by the photodetector 145. The calculation unit 1401 is located outside the housing 146.

[0055] The probe 141 includes a lens 141a that focuses light toward the substrate W. The optical axis of the lens 141a is, for example, horizontal, and a reflector 140a is disposed in front of the lens 141a. The reflector 140a reflects light downward toward the substrate W. The reflector 140a reflects the light reflected from the substrate W toward the lens 141a and guides it to the optical fiber 144. Alternatively, the reflector 140a can be omitted, and the lens 141a can be configured with a vertical optical axis. However, using the reflector 140a allows for a reduction in the height of the probe 141, thereby reducing the height of the housing 100.

[0056] While the probe 141 is located inside the housing 100, the box 146 is located outside the housing 100. A light source 143 and a photodetector 145 are located outside the housing 100. The light source 143 and the photodetector 145 are heat sources. By placing the heat sources outside the housing 100, temperature fluctuations inside the housing 100 can be suppressed, thereby suppressing temperature fluctuations in the substrate W and improving the accuracy of substrate W thickness measurement.

[0057] The temperature control unit 147 adjusts the internal temperature of the housing 146 to the desired temperature. The temperature control unit 147 absorbs heat from the heat source inside the housing 146. The heat generated by the light source 143 is greater than the heat generated by the photodetector 145. By using the temperature control unit 147, temperature fluctuations inside the housing 146 can be suppressed, thereby suppressing temperature fluctuations in the photodetector 145. As a result, fluctuations in the thickness measurement value of the substrate W caused by temperature fluctuations in the photodetector 145 can be suppressed.

[0058] The temperature control unit 147 includes, for example, a temperature control plate 148 and a temperature control medium supply device 149. The temperature control plate 148 is, for example, in contact with the bottom surface of the housing 146, and absorbs heat from inside the housing 146. Alternatively, the temperature control plate 148 may be disposed inside the housing 146. The temperature control medium supply device 149 supplies the temperature control medium, pre-adjusted to the desired temperature, to the temperature control plate 148. The temperature control medium flows through the flow path inside the temperature control plate 148 while absorbing heat from the temperature control plate 148. Alternatively, the temperature control medium may be discharged from the temperature control plate 148, cooled by the temperature control medium supply device 149, and then returned to the temperature control plate 148.

[0059] The alignment unit 150 detects the position of the notch in the crystal orientation of the substrate W. The radial and angular coordinates of the notch can be detected using a rotational coordinate system that rotates together with the substrate holding unit 110. The alignment unit 150 detects the position of the notch, for example, by irradiating the periphery of the substrate W with light and then receiving the irradiated light. The alignment unit 150 and the thickness measuring unit 140 can be used to investigate the relationship between the crystal orientation of the substrate W and the variation in the thickness of the substrate W. Furthermore, an orientation plane can be formed at the periphery of the substrate W to replace the notch. The alignment unit 150 can also detect the position of the orientation plane to replace the notch.

[0060] Temperature measuring unit 160 measures the temperature inside the housing 100. Temperature measuring unit 160 transmits the measured data to control unit 190. Humidity measuring unit 161 measures the humidity inside the housing 100. The humidity to be measured is, for example, relative humidity. Humidity measuring unit 161 transmits the measured data to control unit 190. Temperature measuring unit 160 and humidity measuring unit 161 are integrated in Figure 4, but they can also be installed separately.

[0061] The exhaust section 170 discharges gas from the housing 100. Inside the housing 100, dust particles may be generated due to the rotation and movement of the substrate holder 110. The exhaust section 170 discharges the dust particles generated inside the housing 100 along with the gas to the outside of the housing 100, thereby suppressing the adhesion of dust particles to the substrate W. The exhaust section 170 includes, for example, an exhaust conduit 171 and an exhaust source 172 connected to the exhaust conduit 171. The exhaust conduit 171 has, for example, a pair of first exhaust conduits 171a and 171b extending in the Y-axis direction, and a second exhaust conduit 171c connecting the pair of first exhaust conduits 171a and 171b. Each of the pair of first exhaust conduits 171a and 171b has a plurality of exhaust ports 171d spaced apart in the Y-axis direction. The exhaust source 172 is, for example, a vacuum pump.

[0062] As shown in FIG. 5, the inner cover 180, by separating the interior of the housing 100, suppresses the outflow of microparticles generated by the rotation and movement of the substrate holding part 110. The inner cover 180, for example, has: a sidewall 181 arranged along the side of the housing 100 in a square frame shape; and a top plate 182 covering the sidewall 181 from above. An opening is formed in the top plate 182, which serves as a movement channel for the rotating shaft 121. Below the top plate 182, a rotating part 120, a moving part 130, and an exhaust duct 171 are provided. Above the top plate 182, an inlet / outlet 101 is provided. By separating the rotating part 120 and the inlet / outlet 101 with the top plate 182, the outflow of microparticles can be suppressed.

[0063] Next, referring to Figure 7, an example of one of the constituent elements of the control unit 190 will be explained. Furthermore, the functional blocks illustrated in Figure 7 are conceptual and do not necessarily need to be physically constructed as shown. All or part of each functional block can be functionally or physically distributed and integrated in any unit. All or any part of the processing functions performed by each functional block can be implemented by a program executed by the CPU or by hardware constructed from wired logic.

[0064] The control unit 190 is a computer. As shown in Figure 7, the control unit 190 includes: a rotation control unit 191, a movement control unit 192, an exhaust control unit 193, a thickness acquisition unit 194, a temperature acquisition unit 195, a humidity acquisition unit 196, and a thickness correction unit 197. The rotation control unit 191 controls the rotation of the rotation unit 120. The movement control unit 192 controls the movement of the rotation unit 130. The exhaust control unit 193 controls the exhaust of the exhaust unit 170. The thickness acquisition unit 194 acquires the thickness measured by the thickness measurement unit 140. The temperature acquisition unit 195 acquires the temperature measured by the temperature measurement unit 160. The humidity acquisition unit 196 acquires the humidity measured by the humidity measurement unit 161. The thickness correction unit 197 corrects the thickness measured by the thickness measurement unit 140.

[0065] The rotation control unit 191 controls the supply current ISTOP to the motor 122 to be 5% to 20% or less of the supply current IROTATE to the motor 122 when the substrate holding part 110 stops rotating. In the following text, the supply current ISTOP to the motor 122 when the substrate holding part 110 stops rotating is sometimes referred to as the stop current ISTOP. The supply current IROTATE to the motor 122 when the substrate holding part 110 rotates is sometimes referred to as the rotation current IROTATE.

[0066] In the prior art, the stop current ISTOP is set to approximately 50% of the rotation current IROTATE. The motor 122 generates a large amount of heat, resulting in significant heat transfer from the motor 122 to the substrate W via the substrate holder 110. Consequently, the temperature of the substrate W fluctuates greatly, leading to low accuracy in measuring the thickness of the substrate W. In particular, when the substrate holder 110 only holds the central portion of the substrate W, a temperature gradient is generated radially across the substrate W, further reducing the accuracy of thickness measurement.

[0067] In this embodiment, the rotation control unit 191 controls the stop supply current ISTOP to be less than 5% to 20% of the rotation supply current IROTATE. This suppresses heat generation in the motor 122, reduces temperature fluctuations in the substrate W, and improves the accuracy of substrate W thickness measurement. In particular, by holding the substrate W only at its center with the substrate holding portion 110, the generation of a temperature gradient in the radial direction of the substrate W can be suppressed, further improving the accuracy of substrate W thickness measurement.

[0068] Next, referring to Figure 8, an example of setting the correction factor will be explained. First, the second transport device 39 takes the calibration substrate WA from the storage device 61 and moves it into the housing 100 of the substrate thickness measuring device 33 (step S201). The second transport device 39 hands the calibration substrate WA to the substrate holding part 110 and then exits to the outside of the housing 100. The substrate holding part 110 holds the calibration substrate WA. The calibration substrate WA may have the same diameter, the same thickness, and the same material as the substrate W.

[0069] Next, the thickness measuring unit 140 measures the thickness of the calibration substrate WA (step S202). Alternatively, before measuring the thickness of the calibration substrate WA, the alignment unit 150 can detect the notch position of the calibration substrate WA. The position of the thickness measuring point is preset and adjusted by the rotating unit 120 and the moving unit 130 according to the detection result of the alignment unit 150.

[0070] Next, the thickness correction unit 197 sets the following ratio as a correction factor: the ratio (t0 / t1) of the pre-memorized standard thickness t0 of the calibration substrate WA to the thickness t1 of the calibration substrate WA measured in step S202 above (step S203). The standard thickness t0 of the calibration substrate WA is measured using, for example, a measuring device different from the substrate thickness measuring device 33, and is stored in a storage medium corresponding to the position of the measuring point. When there are multiple measuring points, a correction factor can be obtained for each measuring point, or a correction factor common to multiple measuring points can be obtained. As the latter correction factor, for example, the average value of the ratio (t0 / t1) is used.

[0071] Next, the second transport device 39 receives the calibration substrate WA from the substrate holding part 110 and then moves it to the outside of the housing 100 (step S204). The second transport device 39 then transports the calibration substrate WA to the storage device 61. The storage device 61 then stores the calibration substrate WA again. After that, the current process ends. Step S204 (moving out the calibration substrate WA) can be performed after step S202 (measuring the thickness of the calibration substrate WA) or before step S203 (setting the correction coefficient).

[0072] The substrate thickness measuring device 33 of this embodiment measures the thickness of the etched substrate W. In this case, before step S201 (moving in the calibration substrate WA) in FIG8, the second transport device 39 can remove the calibration substrate WA from the storage device 61 and transport it to the etching device 32A or 32B. The calibration substrate WA is cleaned with pure water by the etching device 32A or 32B, then dried, and then transported into the housing 100 of the substrate thickness measuring device 33 by the second transport device 39. The thickness t1 of the calibration substrate WA can be measured in the same state as the substrate W, and a correction coefficient, i.e., ratio (t0 / t1), can be set.

[0073] Furthermore, the temperature acquisition unit 195 uses the temperature measuring unit 160 to acquire the temperature T0 inside the housing 100 when the thickness t1 of the calibration substrate WA is measured, and stores it in the storage medium. Additionally, the humidity acquisition unit 196 uses the humidity measuring unit 161 to acquire the humidity H0 inside the housing 100 when the thickness t1 of the calibration substrate WA is measured, and stores it in the storage medium.

[0074] Next, referring to FIG9, an example of substrate thickness correction will be described. First, the temperature acquisition unit 195 uses the temperature measurement unit 160 to acquire the temperature T inside the housing 100 (step S301). Next, the thickness correction unit 197 checks whether the temperature T acquired by the temperature acquisition unit 195 is within the allowable range (step S302). The allowable range is represented by a lower limit Tmin and an upper limit Tmax. The lower limit Tmin and the upper limit Tmax are set according to the temperature T0 inside the housing 100 when the thickness t1 of the correction substrate WA is measured, for example, the temperature T0 is set to be between the lower limit Tmin and the upper limit Tmax.

[0075] If the temperature T obtained by the temperature acquisition unit 195 is within the allowable range (step S302, yes), steps S303 to S306 described later will be performed to measure and correct the thickness of the substrate W.

[0076] First, in step S303, the second transport device 39 transports the substrate W into the housing 100 of the substrate thickness measuring device 33 (step S303). The second transport device 39 then hands the substrate W to the substrate holding part 110 and then withdraws it to the outside of the housing 100. The substrate holding part 110 holds the substrate W.

[0077] Next, the thickness measuring unit 140 measures the thickness t2 of the substrate W (step S304). Alternatively, before measuring the thickness t2 of the substrate W, the alignment unit 150 can detect the notch position of the substrate W. The position of the thickness measuring point is preset and adjusted by the rotating unit 120 and the moving unit 130 according to the detection result of the alignment unit 150.

[0078] Next, the thickness correction unit 197 corrects the thickness t2 of the substrate W measured in step S304 (step S305). Specifically, the thickness correction unit 197 calculates the product (t2×t0 / t1) of the thickness t2 measured by the thickness measurement unit 140 and a preset correction coefficient (t0 / t1) as the corrected thickness. This improves the accuracy of the thickness measurement of the substrate W.

[0079] Next, the second conveying device 39 receives the substrate W from the substrate holding part 110 and then moves it to the outside of the housing 100 (step S306). After that, the process ends. Step S306 (moving out the substrate W) can be performed after step S304 (measuring the thickness of the substrate W) or before step S305 (correcting the thickness of the substrate W).

[0080] On the other hand, if the temperature T obtained by the temperature acquisition unit 195 is outside the allowable range (step S302, no), steps S201 to S204 shown in FIG8 will be performed to calculate the correction coefficient (t0 / t1) again and change the setting. After that, the processing after step S301 shown in FIG9 will be performed again.

[0081] In this embodiment, as described above, when the temperature T measured by the temperature measuring unit 160 exceeds a preset allowable range, the thickness correction unit 197 will change the setting of the correction coefficient. Then, the thickness correction unit 197 uses the changed correction coefficient to correct the thickness t2 of the substrate W measured by the thickness measuring unit 140. By appropriately changing the setting of the correction coefficient relative to temperature variations in the substrate W, the accuracy of substrate W thickness measurement can be improved.

[0082] The thickness correction unit 197 can also correct the thickness t2 measured by the thickness measurement unit 140 based on the humidity measured by the humidity measurement unit 161. As shown in Figure 10, the higher the humidity, the smaller the thickness measurement value tends to be. This tendency is approximated by a linear equation. The slope α of the change in the thickness measurement value relative to the change in humidity is, for example, negative. By correcting the thickness t2 according to the humidity, the measurement accuracy of the thickness t2 can be improved.

[0083] For example, the thickness correction unit 197 first calculates the difference ΔH (ΔH=H-H0) between the humidity H0 inside the housing 100 when the thickness t1 of the correction substrate WA is measured and the humidity H inside the housing 100 when the thickness t2 of the substrate W is measured. Next, the thickness correction unit 197 calculates the product (ΔH×a) of the above difference (ΔH=H-H0) and the slope a of the change in the thickness measurement value relative to the change in humidity, as shown in FIG. 10. As the corrected thickness, the thickness correction unit 197 calculates the difference (t2-ΔH×a) between the thickness t2 measured by the thickness measurement unit 140 and the above product (ΔH×a).

[0084] Next, referring to FIG11, an example of the variation in the thickness measurement value relative to the change in the distance L between the probe 141 and the substrate W will be explained. In FIG11, the distance L is zero (0), meaning that the focal point of the lens 141a is aligned with the substrate W. As shown in FIG11, the farther the distance L is from zero, the more easily the thickness measurement value changes.

[0085] Sometimes, when the probe 141 is fixed, the distance L may change. For example, the causes of the distance L change include: (1) the expansion and contraction of the component due to temperature changes, (2) the thickness change between the substrates W, (3) the tilt of the guide rail 133, (4) the surface accuracy of the substrate holding part 110, and (5) the bending of the substrate W due to its own weight.

[0086] In order to minimize the variation in thickness measurement caused by the change in distance L as described in (1) to (5) above, probe 141 is set at a position where the distance L is zero. Specifically, probe 141 is set at the position where the light intensity is the maximum detected by the photodetector 145.

[0087] Figure 12 shows an example of the variation in light intensity detected by photodetector 145 and the variation in thickness measurement value relative to the change in distance L between probe 141 and substrate W. In Figure 12, the variation in thickness measurement value is caused by the above (1) to (5).

[0088] As shown in Figure 12, if the probe 141 is placed at the position where the light intensity detected by the photodetector 145 is the greatest, that is, if the distance L is zero, the variation range of the thickness measurement value will be minimized as much as possible. Therefore, the thickness of the substrate W can be measured with good accuracy.

[0089] The above describes embodiments of the substrate thickness measuring apparatus, substrate processing system, and substrate thickness measuring method of the present invention, but the present invention is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations can be made within the scope described in the claims. These are naturally also included within the technical scope of the present invention.

[0090] 1: Substrate processing system 100: Casing 101: Moving in and out 10: Suppress the shell 110:Substrate holding part 120: Rotating part 121: Rotation axis 122: Motor 130: Mobile Department 131: Motor 132: Ball screw 133: Guide rail 134: Slider 140: Thickness Measurement Section 140a: Reflector 1401: Calculation Department 141: Probe 141a: Lens 142: Fiber Optic 143: Light Source 144: Fiber Optic 145: Light Detector 146: Box 147: Temperature Control Section 148: Temperature Control Plate 149: Temperature-controlled media supply unit 150: Opposing part 160: Temperature Measurement Section 161: Humidity Measurement Department 170: Exhaust section 171: Exhaust duct 171a, 171b: First exhaust duct 171c: Second exhaust duct 171d: Exhaust port 172: Exhaust source 180: Inner cover 181: Sidewall 182: Top Plate 190: Control Department 191: Rotary Control Unit 192: Motion Control Department 193: Exhaust Control Unit 194: Thickness Acquisition Section 195: Temperature Acquisition Department 196: Humidity Acquisition Department 197: Thickness Correction Department 2: Moving in and moving out blocks 21: Loading section 3: Cleaning Block 31A, 31B: Cleaning devices 32A, 32B: Etching apparatus 33: Substrate thickness measuring device 34: Tilting device 35: Transfer device 36: First Transport Area 37: Second Transport Area 38: First transport device 39: Second transport device 5: Grinding Block 51: Rotary Table 52A, 52B, 52C, 52D: Holding section 53A, 53B: Tool Drive Unit 54: Internal Transportation Department 57A, 57B, 57C: Temporary storage area 58: Flip-over section 61: Storage device 9: Control Department 91: CPU (Central Processing Unit) 92: Storage Media a: slope A0: The second move-in and move-out location A1: Grinding position 1 A2: Second grinding position A3: The first move-in and move-out location C: Wafer cassette D: Grinding tools H,H0: Humidity IROTATE: Current ISTOP: Current L: Distance R1, R2: Center lines of rotation S101~S111: Steps S201~S204: Steps S301~S306: Steps T0: Temperature T: Temperature TR1, TR2: Transport path Tmax: Upper limit value Tmin: Lower limit value t0: Standard thickness t1: Thickness W: substrate WA: Calibration substrate

Claims

1. A substrate thickness measuring device, comprising: The substrate holding part holds the substrate; The thickness measuring unit measures the thickness of the substrate held by the substrate holding unit; the housing houses at least a portion of the substrate holding unit and the thickness measuring unit; the temperature measuring unit measures the temperature inside the housing; and the thickness correction unit corrects the thickness measured by the thickness measuring unit. The thickness correction unit performs the following steps: calculating the product of the thickness measured by the thickness measuring unit and a preset correction coefficient as the corrected thickness; and changing the setting of the correction coefficient if the temperature measured by the temperature measuring unit exceeds a preset allowable range.

2. The substrate thickness measuring apparatus as described in claim 1, wherein, The thickness correction unit sets the following ratio as the correction coefficient: the ratio (t0 / t1) of the standard thickness (t0) of the correction substrate that is pre-memorized to the thickness (t1) of the correction substrate measured by the thickness measurement unit.

3. The substrate thickness measuring apparatus as described in claim 2, wherein, When the temperature measured by the temperature measuring unit exceeds the preset allowable range, the thickness correction unit re-measures the thickness (t1) of the calibration substrate using the thickness measuring unit to change the setting of the correction coefficient.

4. The substrate thickness measuring apparatus as described in any of requests 1 to 3, wherein, The thickness measuring unit includes: a probe that illuminates the substrate while receiving the light reflected by the substrate; a light source connected to the probe via an optical fiber; a photodetector connected to the probe via an optical fiber; and a housing that houses the light source and the photodetector; the probe is located inside the housing, and the housing is located outside the housing.

5. The substrate thickness measuring device as described in claim 4 further includes: Temperature control unit, used to regulate the internal temperature of the box.

6. The substrate thickness measuring apparatus as described in claim 4, wherein, The probe is positioned at the location where the light intensity detected by the photodetector is at its maximum.

7. The substrate thickness measuring apparatus as described in any of claims 1 to 3 further includes: A motor causes the substrate holder to rotate. And a rotation control unit to control the motor; The rotation control unit controls the current supplied to the motor when the substrate holding part stops rotating to be less than 5% to 20% of the current supplied to the motor when the substrate holding part rotates.

8. The substrate thickness measuring apparatus as described in any of claims 1 to 3 further includes: The humidity measuring unit measures the humidity inside the housing; the thickness correction unit corrects the thickness measured by the thickness measuring unit based on the humidity measured by the humidity measuring unit.

9. A substrate processing system, comprising: Such as the substrate thickness measuring device requested in any of items 1 to 8; Etching apparatus, etching the substrate; The substrate is transported to the substrate thickness measuring device and the etching device by a transport device. The transport device transports the substrate, which has been etched, cleaned and dried by the etching device, to the substrate thickness measuring device.

10. A substrate processing system, comprising: Such as the substrate thickness measuring device in request item 2 or 3; Storage device for storing the calibration substrate; The substrate and the calibration substrate are transported by the substrate thickness measuring device and the storage device.

11. The substrate processing system of claim 10 further includes: Etching apparatus, etching the substrate; The transport device transports the substrate that has been etched, cleaned, and dried by the etching device, and the calibration substrate that has been cleaned and dried by the etching device, to the substrate thickness measuring device.

12. A method for measuring substrate thickness, using a substrate thickness measuring device to measure the thickness of a substrate; the thickness measuring device comprising: a substrate holding portion for holding the substrate; a thickness measuring portion for measuring the thickness of the substrate held by the substrate holding portion; a housing for housing at least a portion of the substrate holding portion and the thickness measuring portion; and a temperature measuring portion for measuring the temperature inside the housing; the substrate thickness measuring method comprising the following steps: calculating the product of the thickness measured by the thickness measuring portion and a preset correction coefficient as a corrected thickness; and changing the setting of the correction coefficient if the temperature measured by the temperature measuring portion exceeds a preset allowable range.

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