Substrate processing system, substrate processing method, and storage medium

Abstract

A substrate processing system for processing a substrate includes: a grinding unit for grinding a processed surface of the substrate; a thickness measuring unit for measuring the thickness of the substrate; and a control unit for controlling the operation of the thickness measuring unit. The thickness measuring unit comprises: a contact measuring mechanism for measuring the thickness of the substrate in contact with the processed surface of the substrate; and a non-contact measuring mechanism for measuring the thickness of the substrate in a non-contact manner. While the substrate is being ground by the grinding unit, the control unit simultaneously controls the following operations: using the... The control of the contact measurement mechanism for measuring the thickness of the substrate and the non-contact measurement mechanism for determining whether the measurement can be performed are described. In the control of the non-contact measurement mechanism, the difference between a thickness measurement value obtained by the non-contact measurement mechanism and another thickness measurement value obtained immediately before the first thickness measurement value is continuously calculated over time. If the calculated difference continuously converges within a predetermined threshold, it is determined that the thickness measurement of the substrate can be performed, and the control is performed to start the thickness measurement of the substrate using the non-contact measurement mechanism.

Description

Technical Field

[0001] This disclosure relates to a substrate processing system and a substrate processing method. Background Technology

[0002] Patent document 1 discloses a method for measuring the thickness of a wafer as follows: during or after grinding, with the wafer vacuum-adsorbed onto a chuck, a pair of contacts of a two-point process measuring instrument are respectively brought into contact with the surface of the wafer and the surface of the chuck, and the measured height difference is measured as the thickness of the wafer.

[0003] In addition, Patent Document 2 discloses a method in which one side of a substrate is held in a holding unit in a processing apparatus, and a laser is irradiated toward the other side of the substrate in a direction substantially orthogonal to the other side of the substrate. An interference wave of the laser light reflected from one side and the light reflected from the other side is received, and the thickness of the substrate is derived based on the waveform of the interference wave.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-9716

[0007] Patent Document 2: Japanese Patent Application Publication No. 2009-50944 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] The technology disclosed herein appropriately switches the thickness measurement of a substrate during grinding from a thickness measurement using a contact thickness measurement mechanism to a thickness measurement using a non-contact thickness measurement mechanism.

[0010] Solution for solving the problem

[0011] One aspect of this disclosure is a substrate processing system for processing a substrate, the substrate processing system comprising: a grinding unit for grinding a processed surface of the substrate; a thickness measuring unit for measuring the thickness of the substrate; and a control unit for controlling the operation of the thickness measuring unit, wherein the thickness measuring unit includes: a contact measuring mechanism for measuring the thickness of the substrate in contact with the processed surface of the substrate; and a non-contact measuring mechanism for measuring the thickness of the substrate in a non-contact manner, wherein when the substrate is ground by the grinding unit, the control unit simultaneously controls the following operations: The control of the thickness measurement operation performed on the substrate using the contact measurement mechanism; and the determination of whether the measurement can be performed using the non-contact measurement mechanism, wherein the difference between a thickness measurement value obtained by the non-contact measurement mechanism and another thickness measurement value obtained immediately before the first thickness measurement value is continuously calculated over time, and if the calculated difference continuously converges within a predetermined threshold, it is determined that the thickness measurement of the substrate can be performed, and the control to start the thickness measurement operation of the substrate using the non-contact measurement mechanism is performed.

[0012] The effects of the invention

[0013] According to this disclosure, in the thickness measurement of a substrate during grinding, it is possible to appropriately switch from thickness measurement using a contact thickness measurement mechanism to thickness measurement using a non-contact thickness measurement mechanism. Attached Figure Description

[0014] Figure 1 This is a side view showing an outline of the structure of the substrate being processed.

[0015] Figure 2 This is a top view showing an outline of the structure of the processing device.

[0016] Figure 3 This is a side view showing an example of the structure of each grinding section and the retaining disc.

[0017] Figure 4 This is a side view showing an outline of the structure of the contact measuring mechanism.

[0018] Figure 5 This is a side view showing an outline of the structure of the non-contact measuring mechanism.

[0019] Figure 6 This is an explanatory diagram illustrating a thickness measurement performed using a contact measuring mechanism.

[0020] Figure 7 This is an explanatory diagram showing the switching of the thickness measuring unit.

[0021] Figure 8 This is an explanatory diagram showing the switching of the thickness measuring unit.

[0022] Figure 9 This is an explanatory diagram illustrating a thickness measurement performed using a non-contact measuring mechanism.

[0023] Figure 10 This is an explanatory diagram illustrating an example of another substrate processing method. Detailed Implementation

[0024] In recent years, in the manufacturing process of semiconductor devices, the back side of a semiconductor substrate (hereinafter referred to as a "wafer") on which multiple electronic circuits and other devices are formed on its surface is ground to thin the wafer. For example, the back side of the wafer is ground by rotating the substrate holding unit while holding the surface of the wafer in place, and by bringing the grinding stone of the grinding unit against the back side of the wafer.

[0025] While measuring the thickness of the wafer as a product, the wafer is ground to appropriately process it to the target thickness. Patent Document 1 disclosed above discloses a contact-type thickness measuring unit that measures the wafer height by contacting one contact of a two-point process gauge with the surface of a holding disk and the other contact with the upper surface of the wafer (the back side of the grinding surface).

[0026] However, when using a contact-type thickness measurement unit as disclosed in Patent Document 1, the contacts that come into contact with the wafer may damage the back side of the wafer. Furthermore, when using a contact-type thickness measurement unit, the thickness of the protective strip used to protect devices formed on the wafer surface cannot be taken into account when measuring the wafer thickness, meaning the wafer's own thickness cannot be properly measured. Therefore, a non-contact thickness measurement unit, as disclosed in Patent Document 2, has been proposed in the past to measure the wafer's own thickness using the interference wave of a laser without the contacts coming into contact with the wafer.

[0027] However, such non-contact thickness measurement units have limitations in the thickness of wafers they can measure (detection range: for example, 5–300 μm). When the wafer thickness exceeds this detection range, it is necessary to use a contact thickness measurement unit in conjunction. Furthermore, when using both contact and non-contact thickness measurement units in this way, switching from a contact to a non-contact unit during the wafer grinding process may not result in stable wafer thickness measurement. Specifically, when switching from a contact to a non-contact thickness measurement unit at a stage where the wafer thickness cannot be stably and accurately measured using a non-contact unit—for example, when the back side of the wafer, which serves as the incident surface of the laser, is still rough—the wafer thickness may not be accurately measured.

[0028] The technology disclosed herein was developed in view of the above circumstances, appropriately switching from thickness measurement using a contact thickness measurement mechanism to thickness measurement using a non-contact thickness measurement mechanism during substrate thickness measurement in grinding processes. Hereinafter, the processing apparatus and wafer processing method of the wafer processing system according to this embodiment will be described with reference to the accompanying drawings. Furthermore, in this specification and the accompanying drawings, elements having substantially the same functional structure are labeled with the same reference numerals, thereby omitting repeated descriptions.

[0029] In the processing apparatus 1 according to this embodiment, the wafer W, which serves as a substrate, is thinned. The wafer W is, for example, a silicon wafer, a compound semiconductor wafer, or a semiconductor wafer. Figure 1 As shown, a device D is formed on the surface Wa, and a protective strip T for protecting the device D is further bonded on it. Moreover, the back side Wb of the wafer W is subjected to grinding and other processes in the processing apparatus 1, thereby thinning the wafer W.

[0030] like Figure 2 As shown, the processing apparatus 1 has a structure that integrates the loading / unloading station 2 and the processing station 3. The loading / unloading station 2, for example, performs loading and unloading of a cassette C capable of accommodating multiple wafers W with an external device. The processing station 3 is equipped with various processing devices for performing desired processing on the wafers W.

[0031] A cassette loading stage 10 is provided at the loading / unloading station 2. Furthermore, a wafer transport area 20 is provided adjacent to the cassette loading stage 10 on the positive Y-axis side. A wafer transport device 22 is provided in the wafer transport area 20, and this wafer transport device 22 is configured to move freely on a transport path 21 extending along the X-axis direction.

[0032] The wafer transport device 22 has a transport fork 23 for holding and transporting the wafer W. The transport fork 23 is configured to move freely in the horizontal and vertical directions, and to move freely about the horizontal and vertical axes. Furthermore, the wafer transport device 22 is configured to transport the wafer W to the cassette C, the alignment section 50, and the first cleaning section 60 of the cassette stage 10.

[0033] In processing station 3, wafer W undergoes grinding, cleaning, and other processing. Processing station 3 includes a conveying unit 30 for transporting wafer W, a grinding unit 40 for grinding wafer W, an alignment unit 50 for adjusting the horizontal orientation of wafer W before grinding, a first cleaning unit 60 for cleaning the back surface Wb of wafer W after grinding, and a second cleaning unit 70 for cleaning the surface Wa of wafer W after grinding.

[0034] The transport unit 30 is a multi-joint robot equipped with multiple, for example, three arms 31. Each of the three arms 31 is configured to rotate freely. A transport pad 32 for adsorbing and holding the wafer W is mounted on the front arm 31. Furthermore, the base arm 31 is mounted on a lifting mechanism 33 that allows the arm 31 to move vertically. The transport unit 30 is configured to transport the wafer W to the junction position A0 of the grinding unit 40, the alignment unit 50, the first cleaning unit 60, and the second cleaning unit 70.

[0035] A rotary table 41 is provided in the grinding section 40. Four holding disks 42 are provided on the rotary table 41 for adsorbing and holding the wafer W. The holding disks 42 are, for example, porous holding disks, adsorbing and holding the surface Wa (protective tape T) of the wafer W. The surface of the holding disk 42, i.e., the holding surface of the wafer W, has a convex shape in which the central portion protrudes more than the ends when viewed from the side. Furthermore, this central protrusion is minute, but in the illustrations described below, for clarity, the central protrusion of the holding disk 42 is sometimes shown as larger.

[0036] like Figure 3 As shown, the retaining disc 42 is held in the retaining disc base 43. A tilt adjustment mechanism 44 is provided in the retaining disc base 43, which adjusts the relative tilt of each grinding section (rough grinding section 80, intermediate grinding section 90, and fine grinding section 100) with respect to the retaining disc 42. The tilt adjustment mechanism 44 allows the retaining disc 42 and the retaining disc base 43 to tilt, thereby adjusting the relative tilt of the various grinding sections with respect to the upper surface of the retaining disc 42 at machining positions A1 to A3. Furthermore, the structure of the tilt adjustment mechanism 44 is not particularly limited; it can be arbitrarily selected as long as it can adjust the relative angle (parallelism) of the retaining disc 42 with respect to the grinding stone.

[0037] The rotary table 41 rotates, thereby enabling the four holding discs 42 to move to the junction position A0 and the processing positions A1 to A3. In addition, the four holding discs 42 are each configured to rotate about a vertical axis via a rotating mechanism (not shown).

[0038] At the transfer position A0, the wafer W is transferred using the conveyor unit 30. At the processing position A1, a rough grinding unit 80 is configured to perform rough grinding on the wafer W. At the processing position A2, a medium grinding unit 90 is configured to perform medium grinding on the wafer W. At the processing position A3, a fine grinding unit 100 is configured to perform fine grinding on the wafer W.

[0039] The rough grinding section 80 includes a rough grinding wheel 81 with an annular rough grinding stone on its lower surface, a mounting member 82 supporting the rough grinding wheel 81, a spindle 83 that rotates the rough grinding wheel 81 via the mounting member 82, and a drive unit 84, for example, incorporating a motor (not shown). Furthermore, the rough grinding section 80 is configured to be able to rotate along... Figure 2 The pillar 85 shown moves in the vertical direction.

[0040] The intermediate grinding section 90 has the same structure as the coarse grinding section 80. That is, the intermediate grinding section 90 has a mounting member 92, a spindle 93, a drive unit 94, a support column 95, and an intermediate grinding wheel 91 equipped with an annular intermediate grinding stone. The abrasive grains of the intermediate grinding stone are smaller than those of the coarse grinding stone.

[0041] The fine grinding section 100 has the same structure as the rough grinding section 80 and the intermediate grinding section 90. That is, the fine grinding section 100 has a mounting member 102, a spindle 103, a drive unit 104, a support column 105, and a fine grinding wheel 101 equipped with annular fine grinding stones. The abrasive grains of the fine grinding stones are smaller than those of the intermediate grinding stones.

[0042] Furthermore, thickness measuring units for measuring the thickness of the wafer W during the grinding process are provided at the junction A0 and processing positions A1 to A3 of the grinding section 40. Specifically, as shown... Figure 2 As shown, contact-type thickness measuring mechanisms (hereinafter referred to as "contact measuring mechanisms 110") are provided at processing positions A1 and A2, and non-contact-type thickness measuring mechanisms (hereinafter referred to as "non-contact measuring mechanisms 120") are provided at the junction position A0 and processing positions A2 and A3.

[0043] like Figure 4As shown, the contact measurement mechanism 110 includes a height gauge 111 on the holding disk side, a height gauge 112 on the wafer side, and a calculation unit 113. The height gauge 111 includes a probe 114, which contacts the surface of the holding disk 42, i.e., the holding surface of the wafer W, to measure the height position of the holding surface. The height gauge 112 includes a probe 115, which contacts the processing surface of the wafer W, i.e., the back surface Wb, to measure the height position of the back surface Wb. The calculation unit 113 calculates the overall thickness of the wafer W by subtracting the measurement value of the height gauge 111 from the measurement value of the height gauge 112. Furthermore, the overall thickness of the wafer W refers to the thickness obtained by adding the thickness of the device D and the thickness of the protective strip T to the main body thickness of the wafer W. Additionally, the thickness measurement range of the wafer W based on the contact measurement mechanism 110 is, for example, 0 to 2000 μm.

[0044] Furthermore, as shown, the contact measurement mechanism 110 calculates the overall thickness of the wafer W by bringing height gauges 111 and 112 into contact with the surface of the holding disk 42 and the back surface Wb of the wafer W, respectively. However, the thickness data calculated using the contact measurement mechanism 110 is not limited to this overall thickness. For example, if the thicknesses of the guard band T and the device D are known, the main thickness of the wafer W can be calculated by further subtracting the thicknesses of the guard band T and the device D from the measured overall thickness.

[0045] like Figure 5 As shown, the non-contact measurement mechanism 120 includes a sensor 121 and a calculation unit 122. The sensor 121 uses a sensor that measures the bulk thickness of the wafer W without contacting it; for example, a white confocal optical system sensor. The sensor 121 illuminates the wafer W with light having a predetermined wavelength range and receives reflected light from the surface Wa of the wafer W and reflected light from the back surface Wb. The calculation unit 122 calculates the bulk thickness of the wafer W as pulse data based on the two reflected lights received by the sensor 121. Furthermore, the thickness measurement range of the wafer W based on the non-contact measurement mechanism 120 is, for example, 5 to 300 μm.

[0046] Furthermore, the structures of the contact measurement mechanism 110 and the non-contact measurement mechanism 120 are not limited to this embodiment, and any structure can be used. For example, in this embodiment, the sensor 121 of the non-contact measurement mechanism 120 uses a white confocal optical system sensor, but the structure of the non-contact measurement mechanism 120 is not limited to this; any measurement mechanism can be used as long as it is a structure that measures the bulk thickness of the wafer W non-contactly. In addition, multiple sensors 121 can be provided. Furthermore, there is no particular limitation on the light irradiated from the sensor 121, as long as it can be received by the sensor 121 as reflected light; it can be pulsed light or continuous light.

[0047] In this embodiment, as described above, both a contact measuring mechanism 110 and a non-contact measuring mechanism 120 are provided at the processing position A2 as thickness measuring units. Furthermore, at this processing position A2, as will be described later, the thickness measuring unit is switched according to the thickness of the wafer W during the grinding process and the state of the processed surface (back side Wb), i.e., switching from the contact measuring mechanism 110 to the non-contact measuring mechanism 120. Details of the switching operation of the thickness measuring unit will be described later.

[0048] The processing apparatus 1 described above is equipped with a control unit 130. The control unit 130 is, for example, a computer equipped with a CPU, memory, etc., and has a program storage unit (not shown). The program storage unit stores a program for controlling the processing of the wafer W in the processing apparatus 1. Additionally, the program storage unit also stores a program for controlling the switching operation of the thickness measurement unit at the aforementioned processing position A2. Furthermore, the above-mentioned program can be recorded in a computer-readable storage medium H and installed from that storage medium H into the control unit 130.

[0049] Next, the wafer processing method using the processing apparatus 1 configured as described above will be explained.

[0050] First, a cassette C containing multiple wafers W is placed on the cassette mounting stage 10 of the loading / unloading station 2. Next, the wafers W are removed from the cassette C by the transport fork 23 of the wafer transport device 22 and transported to the alignment section 50 of the processing station 3. In the alignment section 50, the horizontal orientation of the wafers W is adjusted by adjusting the position of the notches (not shown) formed on the wafers W.

[0051] Next, the horizontally aligned wafer W is transported from the alignment unit 50 via the transfer unit 30 and handed over to the holding plate 42 at the handover position A0. Then, the rotary table 41 is rotated to move the holding plate 42 sequentially to processing positions A1 to A3, and various grinding processes (rough grinding, medium grinding, and fine grinding) are performed on the back side of the wafer W. Furthermore, in order to grind the wafer W to the desired thickness as described above, the thickness of the wafer W is measured using a thickness measuring unit (contact measuring mechanism 110 and non-contact measuring mechanism 120) while various grinding processes in the grinding unit 40 are performed.

[0052] The various grinding processes in the grinding section 40 and the methods for measuring the thickness of the wafer W are explained in detail.

[0053] At processing position A1, such as Figure 6As shown, with the probe 114 of the height gauge 111 of the contact measuring mechanism 110 in contact with the surface of the holding disk 42 and the probe 115 of the height gauge 112 in contact with the back surface Wb of the wafer W, the back surface Wb of the wafer W is rough ground using the rough grinding section 80. As described above, when measuring the thickness of the wafer W, it is preferable to use a non-contact measuring mechanism 120 that will not damage the back surface Wb of the wafer W and can measure the thickness of the wafer W itself, excluding the thickness of the device D and the guard band T. However, compared with the contact measuring mechanism 110, the non-contact measuring mechanism 120 has a narrow thickness measurement range for the wafer W and cannot measure the thickness of the wafer W immediately after it is loaded into the grinding section 40. Therefore, in the rough grinding process at the processing position A1, the thickness of the wafer W is reduced to, for example, a thickness that can be measured by the non-contact measuring mechanism 120 (e.g., 5 to 300 μm).

[0054] When the wafer W is rough ground to the desired thickness, the rotary table 41 is rotated to move the holding disk 42 (wafer W) to the processing position A2.

[0055] At processing position A2, firstly, while measuring the thickness of wafer W using contact measuring mechanism 110, intermediate grinding is performed on the back surface Wb of wafer W using intermediate grinding unit 90. Then, midway through this intermediate grinding, the thickness measuring unit is switched from contact measuring mechanism 110 to non-contact measuring mechanism 120. As described above, it is preferable to use non-contact measuring mechanism 120 for measuring the thickness of wafer W. However, when non-contact measuring mechanism 120 is used when the roughness of the back surface Wb is high immediately following rough grinding, the reflected light from the back surface Wb may deviate, and stable measurement results may not be obtained.

[0056] Therefore, in this embodiment, at processing position A2, during the initial stage of the intermediate grinding process, the thickness measurement of the wafer W using the contact measuring mechanism 110 and the determination of whether the thickness measurement can be performed using the non-contact measuring mechanism 120 are performed in parallel (hereinafter referred to as the "determination of whether the non-contact measuring mechanism 120 can be measured"). Furthermore, when the roughness of the back surface Wb after rough grinding is improved by the progress of the intermediate grinding process (pre-grinding process), and it is determined that the thickness measurement can be appropriately performed using the non-contact measuring mechanism 120, the thickness measurement using the non-contact measuring mechanism 120 is started, and then the thickness measurement using the contact measuring mechanism 110 is stopped.

[0057] Specifically, at processing position A2 of the processing apparatus 1 involved in this embodiment, firstly, as... Figure 7 As shown in (a), the back surface Wb of the wafer W is subjected to intermediate grinding using the same method as the rough grinding process at machining position A1, i.e., while the thickness is measured using the contact measuring mechanism 110. Figure 8 The process P1). In addition, Figure 8 (a) shows an example of the thickness measurement results of the wafer W by the contact measurement mechanism 110 and the non-contact measurement mechanism 120 at processing position A2. Additionally, Figure 8 (b) shows Figure 8 Details of an example of the measurement results of the non-contact measuring device 120 in (a).

[0058] When the thickness of wafer W is reduced to the desired thickness for improving the roughness of the back surface Wb, then, as Figure 7 As shown in (b), while continuing the intermediate grinding of the back surface Wb and the thickness measurement using the contact measuring mechanism 110, the determination of whether the non-contact measuring mechanism 120 can perform the measurement begins. Figure 8 The process P2). The non-contact measurement mechanism 120 determines whether it can perform a measurement using pulse data calculated based on the body thickness of the wafer W from the reflected light from the surface Wa and back surface Wb of the wafer W, which is irradiated from the sensor 121. Specifically, for example, as... Figure 8 As shown, when the difference between a body thickness data d(n) calculated by the calculation unit 122 and another body thickness data d(n-1) calculated just now converges within a predetermined threshold multiple times, it is determined that accurate thickness measurement can be performed using the non-contact measurement mechanism 120. In other words, when the time deviation of the continuously calculated body thickness data becomes smaller, it is determined that the body thickness measured by the non-contact measurement mechanism 120 is reliable data as a measurement result, and it is determined that accurate thickness measurement can be performed using the non-contact measurement mechanism 120.

[0059] In this embodiment, after improving the roughness of the back surface Wb through intermediate grinding, a determination of whether the non-contact measuring mechanism 120 can perform measurement is made. When the determination of whether measurement can be performed begins when the roughness of the back surface Wb is high, as described above, the reflected light (measured thickness data) from the non-contact measuring mechanism 120 deviates, making it impossible to make a stable determination of whether measurement can be performed. That is, for example, when the measured thickness data deviates and the measured thickness data accidentally converges within a threshold, making accurate thickness measurement by the non-contact measuring mechanism 120 impossible, it may be mistakenly determined that accurate thickness measurement can be performed. Regarding this, by improving the roughness of the back surface Wb and performing the determination of whether measurement can be performed after the deviation of the measured thickness data has decreased, the risk of misjudgment in the determination of whether measurement can be performed can be reduced.

[0060] Furthermore, by determining whether the measured thickness data converges to the threshold multiple times consecutively as described above, the risk of misjudgment in determining whether such measurement is feasible can be reduced more appropriately.

[0061] Furthermore, the data used as the threshold for determination can be, for example, the amount of grinding of the wafer W in each measurement cycle of the non-contact measurement mechanism 120, obtained based on the descent speed of the grinding stone of the intermediate grinding section 90. In this case, the threshold used can be, for example, set to the amount of grinding of the wafer W in each measurement cycle ±1 μm.

[0062] However, the data used as the threshold is not limited to the "grinding amount per measurement cycle," and any data can be used as the threshold. Furthermore, the data value set as the threshold can also be any value. For example, the determination of whether measurement is possible can be made by comparing the thickness measurement value of the non-contact measurement mechanism 120 with the thickness measurement value of the contact measurement mechanism 110. In other words, the thickness measurement result of the wafer W of the contact measurement mechanism 110 can be used as the threshold.

[0063] Furthermore, there is no particular limitation on the number of consecutive times the difference converges within the threshold for determining whether a measurement can be performed using the non-contact measuring mechanism 120, and it can be any number of times, more than two. However, from the viewpoint of reducing the risk of misjudgment in the determination of whether a measurement is possible, as described above, a higher number of consecutive times is preferred.

[0064] When it is determined that measurement can be performed using the non-contact measurement mechanism 120, the measurement capability determination process ends, and the thickness data calculated by the non-contact measurement mechanism 120 is used as the thickness of the wafer W. Furthermore, when thickness measurement using the non-contact measurement mechanism 120 begins, subsequently, as... Figure 7 As shown in (c), the thickness measurement of wafer W performed using the contact measurement mechanism 110 is stopped by disengaging probes 114 and 115. Figure 8 The process P3) thereby switches the thickness measuring unit at processing position A2 from the contact measuring mechanism 110 to the non-contact measuring mechanism 120.

[0065] Furthermore, if it is determined in the determination of whether measurement can be performed that the non-contact measurement mechanism 120 cannot be used, that is, if the time deviation of the continuously calculated body thickness data does not decrease, the thickness measurement unit is not switched, and the intermediate grinding process of wafer W continues. In cases where the thickness measurement unit cannot be switched, an error can be notified immediately after the intermediate grinding process of wafer W is completed, or the grinding process can be continued using the contact measurement mechanism 110.

[0066] When the thickness measurement unit switches from the contact measurement mechanism 110 to the non-contact measurement mechanism 120, the intermediate grinding process at the processing position A2 continues. Furthermore, when the wafer W is intermediately ground to the target thickness, the endpoint is detected, and the grinding feed and grinding of the intermediate grinding unit 90 are terminated. Afterwards, the rotary table 41 is rotated to move the holding disk 42 (wafer W) to the processing position A3.

[0067] At processing position A3, such as Figure 9 As shown, while measuring the main body thickness of wafer W using the non-contact measurement mechanism 120, the back surface Wb of wafer W is finely ground using the fine grinding section 100. At processing position A3, since the thickness of wafer W has been sufficiently reduced and the roughness of the back surface Wb has been improved in the rough grinding section 80 and the intermediate grinding section 90, the thickness can be appropriately measured using the non-contact measurement mechanism 120.

[0068] When the fine grinding of wafer W is completed, the rotary table 41 is rotated to move the holding disk 42 to the junction position A0. At the junction position A0, while the wafer W is rotated, the body thickness of multiple points, including the vicinity of the center and the vicinity of the periphery of the wafer W, is measured using the non-contact measurement mechanism 120, thereby calculating the flatness (TTV: Total Thickness Variation) of the wafer W.

[0069] Next, the wafer W is transferred from the transfer position A0 to the second cleaning unit 70 via the transfer unit 30, and the surface Wa of the wafer W is cleaned while the wafer W is held on the transfer pad 32.

[0070] Next, the wafer W is transferred from the second cleaning unit 70 to the first cleaning unit 60 via the transfer unit 30, and the surface Wa and back side Wb of the wafer W are cleaned using cleaning fluid nozzles (not shown).

[0071] Then, the wafer W, which has undergone all processing, is transferred to the cassette C of the cassette stage 10 via the transfer fork 23 of the wafer transfer device 22. In this way, the series of wafer processing in the processing apparatus 1 is completed.

[0072] In the wafer processing described above, after determining that accurate thickness measurement can be performed using the non-contact measurement mechanism 120 based on the measurement capability determination, the thickness of the wafer W is measured using the calculation data from the non-contact measurement mechanism 120. Then, the thickness measurement unit is switched from the contact measurement mechanism 110 to the non-contact measurement mechanism 120. Therefore, the thickness measurement of the wafer W can be stably continued while switching the thickness measurement unit.

[0073] Furthermore, at this time, in determining whether measurement is possible, if the difference in the body thickness data continuously acquired by the non-contact measuring mechanism 120 converges within a threshold multiple times, it is determined that accurate thickness measurement can be performed using the non-contact measuring mechanism 120. In this way, by determining whether accurate thickness measurement can be performed using the non-contact measuring mechanism 120 after the difference in the body thickness data converges within a threshold multiple times, the risk of misjudgment of whether measurement is possible due to deviations in the measurement data can be reduced. That is, after determining that the body thickness measured by the non-contact measuring mechanism 120 is reliable data as a measurement result, the operation can be appropriately switched from the contact measuring mechanism 110 to the non-contact measuring mechanism 120.

[0074] Furthermore, in this embodiment, after the roughness of the back surface Wb is improved by intermediate grinding of the wafer W, the determination of whether it can be measured begins. As a result, the risk of misjudgment in the determination of whether the non-contact measurement mechanism 120 can be reduced, that is, the operation switch from the contact measurement mechanism 110 to the non-contact measurement mechanism 120 can be performed more appropriately.

[0075] Furthermore, according to this embodiment, the switching operation of the thickness measuring unit can be automatically performed based on the measured pulse data without the need for operator intervention. This suppresses undesirable situations arising from operator intervention and appropriately improves the productivity of the grinding process in the processing apparatus 1.

[0076] Furthermore, in the above embodiments, after improving the roughness of the back surface Wb of wafer W, the thickness measurement of wafer W for determining whether the non-contact measurement mechanism 120 can be measured is started. However, the thickness measurement of wafer W can also start simultaneously with the intermediate grinding process. Alternatively, the determination of whether the measurement can be performed can also start simultaneously with the intermediate grinding process. Even in this case, by starting the thickness measurement of wafer W using the non-contact measurement mechanism 120 after the difference in the body thickness data obtained by the non-contact measurement mechanism 120 converges within a threshold multiple times, the thickness measurement unit can be switched appropriately.

[0077] Furthermore, in the above embodiment, after the thickness of the wafer W is reduced to the thickness measurement range (e.g., 5 to 300 μm) of the non-contact measurement mechanism 120 by the rough grinding section 80 at processing position A1, the wafer W is moved to processing position A2. However, the thickness of the wafer W placed at processing position A2 is not limited to this; a wafer W with a thickness greater than the thickness measurement range of the non-contact measurement mechanism 120 (e.g., exceeding 300 μm) may also be placed at processing position A2. In this case, after the thickness of the wafer W is reduced to the thickness measurement range of the non-contact measurement mechanism 120 by the intermediate grinding section 90 at processing position A2 (pre-grinding process), the determination of whether the non-contact measurement mechanism 120 can measure the thickness begins.

[0078] Furthermore, the above embodiments have been described using a three-axis structure (rough grinding section 80, intermediate grinding section 90, and fine grinding section 100) for the grinding section 40. However, if a switching operation of the thickness measuring section is required during the grinding process, the structure of the grinding section 40 is not limited to this. For example, the grinding section may be a dual-axis structure with only a rough grinding section 80 (or an intermediate grinding section 90) and a fine grinding section 100, or it may be a single-axis structure with only one grinding section.

[0079] Furthermore, in the above embodiments, the example described is the thinning of the back surface Wb of the wafer W by grinding in the grinding section 40 of the processing apparatus 1; however, the method for thinning the wafer W is not limited to this. Specifically, even in cases such as Figure 10 As shown in (a), the modified layer M is formed by irradiating the interior of the wafer W with a laser (e.g., a YAG laser) and as shown in (a). Figure 10 The techniques disclosed herein can also be applied when wafer W is separated from the modified layer M as shown in (b) to thin it. However, in this case of separating wafer W from the modified layer M, the separation surface of wafer W has a high roughness due to the residual modified layer M (damaged layer), which may prevent accurate thickness measurement using the non-contact measurement mechanism 120. Therefore, as... Figure 10 As shown in (c), in the grinding process for removing the damaged layer, firstly, while measuring the thickness using the contact measuring mechanism 110, a determination is made as to whether the non-contact measuring mechanism 120 can measure the thickness. After improving the roughness of the separation surface (after removing the damaged layer), the process switches to the non-contact measuring mechanism 120.

[0080] Furthermore, in the above embodiments, light is irradiated from the sensor 121 of the non-contact measurement mechanism 120, and a determination of whether measurement is possible is made based on pulse data calculated from the reflected light from the wafer W. However, the data used for determining whether measurement is possible is not limited to pulse data; for example, continuous data calculated from the reflected light of continuous light can also be used to determine whether measurement is possible. In this case, the determination of whether measurement is possible can be made by determining whether the calculated body thickness data continuously converges within a desired timeframe, instead of determining whether the difference in body thickness data continuously converges within a threshold multiple times, as in the embodiments described above.

[0081] Furthermore, in the above embodiments, such as Figure 1 As shown, the example described uses a single wafer W, which serves as the substrate and has a device D and a guard band T on its surface Wa. However, the structure of the wafer W is not limited to the above embodiment. Specifically, the technology disclosed herein can also be applied when the first wafer in an overlapping wafer formed by bonding a first wafer with a device formed on its surface and a second wafer with the device formed on their surfaces is thinned.

[0082] The embodiments disclosed herein should be considered illustrative in all respects, not restrictive. The above embodiments may be omitted, substituted, or modified in various ways without departing from the appended claims and their spirit.

[0083] Explanation of reference numerals in the attached figures

[0084] 1: Processing unit; 40: Grinding unit; 110: Contact measuring mechanism; 120: Non-contact measuring mechanism; 130: Control unit; W: Wafer; Wb: Back side.

Claims

1. A substrate processing system for processing a substrate, the substrate processing system comprising: The grinding section grinds the processing surface of the substrate; A thickness measuring unit that measures the thickness of the substrate; and The control unit controls the operation of the thickness measuring unit. in, The thickness measuring unit includes: a contact measuring mechanism that measures the thickness of the substrate by contacting the processed surface of the substrate; and a non-contact measuring mechanism that measures the thickness of the substrate by not contacting the substrate. When the substrate is ground using the grinding unit, the control unit simultaneously controls the following operation: the thickness measurement operation of the substrate using the contact measuring mechanism; And a determination of whether the measurement can be performed using the non-contact measuring mechanism. In the control of whether or not the determination action can be measured... The difference between a thickness measurement value obtained by the non-contact measuring mechanism and another thickness measurement value obtained immediately before the first thickness measurement value is calculated continuously over time. If the calculated difference continuously converges to a predetermined threshold over time, it is determined that the thickness measurement of the substrate can be performed, and control is initiated to start the thickness measurement operation of the substrate using the non-contact measurement mechanism.

2. The substrate processing system according to claim 1, characterized in that, After the thickness measurement operation using the non-contact measuring mechanism begins, the control unit controls the contact measuring mechanism to move away from the processing surface, thereby stopping the thickness measurement operation using the contact measuring mechanism.

3. The substrate processing system according to claim 1 or 2, characterized in that, The control unit controls the use of the thickness measurement results of the substrate obtained by the contact measuring mechanism as the threshold.

4. The substrate processing system according to claim 1 or 2, characterized in that, Before determining whether the non-contact measuring mechanism can be used for measurement, the control unit controls the operation of the grinding unit to perform pre-grinding treatment on the machining surface.

5. The substrate processing system according to claim 4, characterized in that, During the pre-grinding process, the control unit controls the operation of the thickness measuring unit so that the contact measuring mechanism performs the thickness measuring operation of the substrate.

6. The substrate processing system according to claim 4, characterized in that, In the pre-grinding process, the processing surface of the substrate having a thickness within the detection range of the non-contact measuring mechanism is ground to a predetermined thickness in order to reduce the roughness of the processing surface.

7. The substrate processing system according to claim 4, characterized in that, In the pre-grinding process, the processing surface of the substrate having a thickness outside the detection range of the non-contact measuring mechanism is ground until the thickness of the substrate is within the detection range.

8. A substrate processing method for processing a substrate, the substrate processing method comprising: The processing surface of the substrate is ground; The thickness of the substrate is measured using a contact measuring mechanism in parallel with the grinding of the machined surface; In parallel with the grinding of the processed surface and the thickness measurement using a contact measuring mechanism, it is determined whether a non-contact measuring mechanism can be used to measure the thickness of the substrate. as well as Based on the determination that the non-contact measurement mechanism can perform the measurement, the thickness of the substrate is then measured using the non-contact measurement mechanism. In determining whether the non-contact measuring mechanism can perform the measurement, The difference between a thickness measurement value obtained by the non-contact measuring mechanism and another thickness measurement value obtained immediately before the first thickness measurement value is calculated continuously over time. If the calculated difference continuously converges to a predetermined threshold over time, it is determined that the thickness of the substrate can be measured.

9. The substrate processing method according to claim 8, characterized in that, include: After the thickness measurement of the substrate using the non-contact measuring mechanism begins, the thickness measurement of the substrate using the contact measuring mechanism is stopped.

10. The substrate processing method according to claim 8 or 9, characterized in that, The thickness measurement result of the substrate obtained by the contact measuring mechanism is used as the threshold.

11. The substrate processing method according to claim 8 or 9, characterized in that, Before the non-contact measuring mechanism can perform the measurement, the pre-grinding process of the machined surface is carried out. During the pre-grinding process of the machined surface, the thickness of the substrate is measured using the contact measuring mechanism.

12. The substrate processing method according to claim 11, characterized in that, In the pre-grinding process, the processing surface of the substrate having a thickness within the detection range of the non-contact measuring mechanism is ground to a predetermined thickness in order to reduce the roughness of the processing surface.

13. The substrate processing method according to claim 11, characterized in that, In the pre-grinding process, the processing surface of the substrate having a thickness outside the detection range of the non-contact measuring mechanism is ground until the thickness of the substrate is within the detection range.

14. A readable computer storage medium storing a program that runs on a computer controlling a substrate processing system to cause the substrate processing system to execute a substrate processing method for processing a substrate. The substrate processing system has: The grinding section grinds the processing surface of the substrate; A thickness measuring unit that measures the thickness of the substrate; and The control unit controls the operation of the thickness measuring unit. in, The thickness measuring unit includes: A contact-type measuring mechanism that measures the thickness of the substrate by contacting the processed surface of the substrate; as well as A non-contact measurement mechanism that measures the thickness of the substrate in a non-contact manner. The substrate processing method includes: The processing surface of the substrate is ground; The thickness of the substrate is measured using a contact measuring mechanism in parallel with the grinding of the machined surface; In parallel with the grinding of the processed surface and the thickness measurement using a contact measuring mechanism, it is determined whether a non-contact measuring mechanism can be used to measure the thickness of the substrate; and Based on the determination that the non-contact measurement mechanism can perform the measurement, the thickness of the substrate is then measured using the non-contact measurement mechanism. In determining whether the non-contact measuring mechanism can perform the measurement, The difference between a thickness measurement value obtained by the non-contact measuring mechanism and another thickness measurement value obtained immediately before the first thickness measurement value is calculated continuously over time. If the calculated difference continuously converges to a predetermined threshold over time, it is determined that the thickness of the substrate can be measured.

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