Substrate processing method and substrate processing system

Abstract

A substrate processing method is used for processing a substrate, and the substrate processing method comprises the following steps: grinding the surface of the substrate; in the substrate processing method, the surfaces of a plurality of substrates are ground and etched, and when it is expected that the ground surface shape of a first substrate is different from the ground surface shape of a second substrate following the first substrate, the ground surface shape of the first substrate is different from the ground surface shape of the second substrate, and the ground surface shape of the second substrate is different from the ground surface shape of the second substrate. The plurality of substrates are divided into a plurality of groups with a boundary between the first substrate and the second substrate, and the target thickness after grinding of the substrates up to the nth substrate in the group with the second substrate as the first substrate is made larger than the target thickness after grinding of the (n + 1) th and subsequent substrates, where n is a natural number of 1 or more.

Description

Technical Field

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

[0002] Patent Document 1 discloses a substrate processing method, including: a grinding step for grinding the surface of a substrate; a measurement step for measuring the thickness of the ground substrate; a condition determination step for determining the processing conditions for wet etching of the substrate based on the measured thickness of the substrate; and a damage layer removal step for supplying a processing solution to the ground substrate based on the determined processing conditions to perform wet etching to remove the damage layer formed on the surface of the substrate.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2017 / 018219 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The technology disclosed herein is used to properly control the surface shape of a substrate after grinding and etching of the substrate surface.

[0008] Solution for solving the problem

[0009] One aspect of this disclosure is a substrate processing method for processing a substrate, comprising the following processes: grinding the surface of the substrate; and etching the surface of the ground substrate. In the substrate processing method, the surfaces of multiple substrates are ground and etched. When it is anticipated that the surface shape of the ground first substrate will be different from the surface shape of the ground second substrate following the first substrate, the multiple substrates are divided into multiple groups with the boundary between the first substrate and the second substrate as the boundary. The target thickness of the ground substrates up to the nth (n is a natural number greater than 1) substrate in the group with the second substrate as the first substrate is greater than the target thickness of the ground substrates of the (n+1)th and subsequent substrates.

[0010] The effects of the invention

[0011] According to this disclosure, the surface shape of the substrate after grinding and etching can be appropriately controlled. Attached Figure Description

[0012] Figure 1 This is a top view showing the outline of the wafer processing system's structure.

[0013] Figure 2This is a side view showing an outline of the structure of the etching apparatus.

[0014] Figure 3 This is an explanatory diagram showing the situation where the nozzle moves radially.

[0015] Figure 4 This is a side view showing an example of the structure of the grinding unit and the retaining disc.

[0016] Figure 5 This is a flowchart showing the main processes involved in wafer processing.

[0017] Figure 6 This is a flowchart illustrating the main steps of the method for determining optimal etching conditions.

[0018] Figure 7 This is an explanatory diagram showing the grinding process controlling the first surface of the wafer.

[0019] Figure 8 This is an illustration showing the process of grinding and etching both sides of a wafer in a group.

[0020] Figure 9 This is an illustration showing the process of grinding and etching one side of a wafer in a group. Detailed Implementation

[0021] In the semiconductor device manufacturing process, the cut surfaces of disk-shaped silicon wafers (hereinafter referred to as "wafers") cut from single-crystal silicon ingots using a wire saw or similar tool are planarized and further smoothed to homogenize the wafer's thickness. For example, planarization of the cut surfaces is achieved through surface grinding or polishing. Smoothing is achieved, for example, through spin etching, in which etchant is supplied from above the cut surfaces of the wafer while it is being rotated.

[0022] Patent Document 1 disclosed a method of performing wet etching on a ground wafer and removing a damage layer formed on the surface of the wafer through grinding. In the condition determination process described in Patent Document 1, the operation of the nozzle supplying the processing liquid, the wafer rotation speed, the amount of processing liquid supplied, the supply time of the processing liquid, and the type of processing liquid, which are processing conditions for wet etching, are determined based on the thickness of the wafer obtained in the measurement process.

[0023] Here, sometimes the thickness of the ground wafer is uneven within the wafer surface. For example, if the central portion of the ground wafer is concave relative to the outer periphery and the amount of concavity is large, when wet etching is performed on the wafer surface to make the thickness uniform within the ground wafer surface, the etching amount in the central portion of the wafer is less than that in the outer periphery. As mentioned above, one of the purposes of wet etching is to remove the damage layer on the wafer surface, but in the above case, it may not be possible to sufficiently remove the damage layer formed in the central portion of the wafer surface.

[0024] The technology disclosed herein is used to appropriately control the surface shape of a substrate after grinding and etching. Hereinafter, a wafer processing system, which is the substrate processing system according to this embodiment, and a wafer processing method, which is the substrate processing method, 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 omitted from repeated description by using the same reference numerals.

[0025] In the wafer processing system 1 according to this embodiment, a wafer W, which serves as a substrate and is cut from a spindle, is subjected to a process to improve the in-plane uniformity of its thickness. Hereinafter, the cut surfaces of the wafer W will be referred to as the first surface Wa and the second surface Wb. The first surface Wa is the surface opposite to the second surface Wb. In addition, the first surface Wa and the second surface Wb are sometimes collectively referred to as the surfaces of the wafer W.

[0026] like Figure 1 As shown, the wafer processing system 1 has a structure that integrates the loading / unloading station 2 and the processing station 3. A cassette C capable of accommodating multiple wafers W is loaded and unloaded between the loading / unloading station 2 and, for example, an external location. The processing station 3 is equipped with various processing devices for performing desired processing on the wafers W.

[0027] A cassette loading stage 10 for holding multiple, for example, three cassettes C, is provided at the loading / unloading station 2. Furthermore, a wafer transport device 20 is provided adjacent to the cassette loading stage 10 on the negative X-axis side. The wafer transport device 20 is configured to move freely along a transport path 21 extending along the Y-axis. The wafer transport device 20 also has, for example, two transport arms 22, 22 for holding and transporting wafers W. Each transport arm 22 is configured to move freely in the horizontal and vertical directions and about the horizontal and vertical axes. Moreover, the structure of the transport arms 22 is not limited to this embodiment, and any structure can be adopted. Furthermore, the wafer transport device 20 is configured to transport wafers W to the cassettes C of the cassette loading stage 10 and the transport device 30 described later.

[0028] On the negative X-axis side of the wafer transfer device 20 at the inlet / outlet station 2, a transfer device 30 is provided adjacent to the wafer transfer device 20. The transfer device 30 is used to transfer wafers W between the inlet / outlet station 2 and the processing station 3.

[0029] Processing station 3 is provided with, for example, three processing blocks G1 to G3. The first processing block G1, the second processing block G2, and the third processing block G3 are arranged sequentially from the positive X-axis direction side (the side of the transfer station 2) to the negative direction side.

[0030] The first processing block G1 is equipped with an etching device 40, a thickness measuring device 50, a flipping device 51, and a wafer transport device 60. The etching device 40, the thickness measuring device 50, and the flipping device 51 are stacked. However, the number and arrangement of the etching device 40, the thickness measuring device 50, and the flipping device 51 are not limited thereto.

[0031] The etching apparatus 40 uses the grinding apparatus 90 (described later) to etch the silicon (Si) on the ground first surface Wa or the ground second surface Wb. Multiple etching apparatuses 40 may be provided to improve wafer processing productivity.

[0032] like Figure 2 As shown, the etching apparatus 40 includes a wafer holding section 41, a rotating mechanism 42, a nozzle 43, and a moving mechanism 44.

[0033] The wafer holding section 41 holds the outer edge of the wafer W at multiple points, specifically three points in this embodiment. Furthermore, the structure of the wafer holding section 41 is not limited to the illustrated example; for instance, the wafer holding section 41 may also include a holding disk (not shown) that holds the wafer W from below. The wafer holding section 41 is configured to rotate about a vertical rotation center line 41a via a rotation mechanism 42, thereby enabling the wafer W held on the wafer holding section 41 to rotate.

[0034] The nozzle 43 supplies etching solution E to the first surface Wa or the second surface Wb of the wafer W held in the wafer holding portion 41. The nozzle 43 is connected to an etching solution supply source (not shown) that supplies the etching solution E to the nozzle 43. The nozzle 43 is disposed above the wafer holding portion 41 and is configured to be movable in both the horizontal and vertical directions via a moving mechanism 44. In one example, the nozzle 43 is configured to pass through the rotation center line 41a of the wafer holding portion 41, i.e., ... Figure 3 As shown, it can reciprocate (scanning) or rotate above the center of wafer W.

[0035] The etching solution E contains hydrofluoric acid (HF), nitric acid (HNO3), and phosphoric acid (H3PO4) to appropriately etch the silicon of the wafer W, which can be the object of etching. In one example, the etching solution E is a mixture containing hydrofluoric acid, nitric acid, phosphoric acid, and water. Furthermore, the object of etching can also be, for example, amorphous silicon.

[0036] In one case, Figure 1 The thickness measuring device 50 shown includes a measuring unit (not shown) and a calculation unit (not shown). The measuring unit includes sensors that measure the thickness of the etched wafer W at multiple points. The calculation unit obtains the thickness distribution of the wafer W based on the measurement results (thickness of the wafer W) from the measuring unit, and calculates the thickness deviation (TTV: Total Thickness Variation) of the wafer W. The thickness deviation of the wafer W is the difference between the thickness of the target shape and the measured thickness. Alternatively, the calculation of the thickness distribution and thickness deviation of the wafer W can be performed by the control device 120 described later, instead of the calculation unit. In other words, the calculation unit (not shown) can also be provided within the control device 120 described later. Furthermore, the structure of the thickness measuring device 50 is not limited to this and can be configured arbitrarily.

[0037] The flipping device 51 flips the first surface Wa and the second surface Wb of the wafer W in the vertical direction. The structure of the flipping device 51 is arbitrary.

[0038] The wafer transport device 60 is disposed on the negative X-axis side of the transport device 30. The wafer transport device 60 has, for example, two transport arms 61, 61 that hold and transport the wafer W. Each transport arm 61 is configured to move freely in the horizontal and vertical directions and about the horizontal and vertical axes. Moreover, the wafer transport device 60 is configured to transport the wafer W to the transport device 30, the etching device 40, the thickness measuring device 50, the flipping device 51, the cleaning device 70 (described later), the thickness measuring device 71 (described later), the buffer device 72 (described later), and the flipping device 73 (described later).

[0039] The second processing block G2 is equipped with a cleaning device 70, a thickness measuring device 71, a buffer device 72, a flipping device 73, and a wafer transport device 80. The cleaning device 70, thickness measuring device 71, buffer device 72, and flipping device 73 are stacked. Furthermore, the number and arrangement of the cleaning device 70, thickness measuring device 71, buffer device 72, and flipping device 73 are not limited thereto.

[0040] The cleaning device 70 cleans at least the first surface Wa or the second surface Wb of the grinding device 90 after grinding.

[0041] In one example, the thickness measuring device 71 has the same structure as the thickness measuring device 50 described above. However, the structure of the thickness measuring device 71 is not limited to this and can be configured arbitrarily.

[0042] The buffer device 72 temporarily holds the wafer W before it is transferred from the first processing block G1 to the second processing block G2. The structure of the buffer device 72 is arbitrary. Alternatively, the buffer device 72 may also have an alignment mechanism (not shown) for adjusting the center position of the wafer W relative to the holding disks 93a, 93b (described later) and / or the orientation of the wafer W in the horizontal direction.

[0043] The flipping device 73 flips the first surface Wa and the second surface Wb of the wafer W in the vertical direction. The structure of the flipping device 73 is arbitrary.

[0044] The wafer transport device 80 is, for example, disposed on the positive Y-axis side of the cleaning device 70, the thickness measuring device 71, the buffer device 72, and the flipping device 73. The wafer transport device 80 has, for example, two transport arms 81, 81 that use an adsorption and holding surface (not shown) to adsorb and hold the wafer W and transport it. Each transport arm 81 is supported by a multi-jointed arm member 82 and is configured to move freely in the horizontal and vertical directions and about the horizontal and vertical axes. Furthermore, the wafer transport device 80 is configured to transport the wafer W to the etching device 40, the thickness measuring device 50, the flipping device 51, the cleaning device 70, the thickness measuring device 71, the buffer device 72, the flipping device 73, and the grinding device 90 (described later).

[0045] A grinding device 90 is provided in the third processing block G3. The grinding device 90 grinds the first surface Wa or the second surface Wb of the wafer W to make it planar.

[0046] The grinding apparatus 90 includes a rotary table 91. The rotary table 91 is configured to rotate freely around a vertical rotation centerline 92 via a rotation mechanism (not shown). Four holding disks 93a and 93b, serving as substrate holding portions, are provided on the rotary table 91 to hold and hold the wafer W. For example, porous holding disks are used for the holding disks 93a and 93b. The surface of the holding disks 93a and 93b, i.e., the holding surface of the wafer W, has a convex shape in side view where the central portion protrudes more than the outer periphery. Furthermore, this central protrusion is minute, but in the following description, for clarity, the central protrusion of the holding disks 93a and 93b is sometimes shown as larger.

[0047] Two of the four retaining discs 93a and 93b are first retaining discs 93a used for grinding at the first machining position B1 (described later). These two first retaining discs 93a are arranged symmetrically across the rotation center line 92. The remaining two second retaining discs 93b are used for grinding at the second machining position B2 (described later). These two second retaining discs 93b are also arranged symmetrically across the rotation center line 92. That is, the first retaining discs 93a and the second retaining discs 93b are arranged alternately in the circumferential direction.

[0048] like Figure 4 As shown, four retaining discs 93a and 93b are respectively held in four retaining disc bases 94. A tilt adjustment mechanism 95, described later, is provided in the retaining disc base 94 for adjusting the relative tilt of the grinding sections 101 and 111 with the retaining discs 93a and 93b. The tilt adjustment mechanism 95 has a fixed shaft 96 provided on the lower surface of the retaining disc base 94, and multiple, for example, two lifting shafts 97. Each lifting shaft 97 is configured to extend and retract freely to raise and lower the retaining disc base 94. Through this tilt adjustment mechanism 95, with one end of the outer periphery of the retaining disc base 94 (the position corresponding to the fixed shaft 96) as a base point, the other end is raised and lowered in the vertical direction via the lifting shafts 97, thereby tilting the retaining discs 93a and 93b and the retaining disc base 94. Furthermore, this allows adjustment of the relative tilt of the grinding surfaces of the grinding sections 101 and 111 at machining positions B1 to B2 (described later) with the upper surfaces of the retaining discs 93a and 93b. Furthermore, the structure of the tilt adjustment mechanism 95 is not limited to this, as long as it can adjust the relative angle (parallelism) of the surfaces (holding surfaces) of the holding discs 93a and 93b relative to the grinding surfaces of each grinding section 101 and 111.

[0049] like Figure 1 As shown, by rotating the rotary table 91, the four holding discs 93a and 93b can be moved to the junction positions A1~A2 and the processing positions B1~B2. In addition, the four holding discs 93a and 93b are each configured to be able to rotate about a vertical axis by a rotating mechanism (not shown).

[0050] The first handover position A1 is located on the positive X-axis and positive Y-axis side relative to the rotation center line 92 of the rotary table 91, and is used for handing over the wafer W to the first holding disk 93a during grinding of the first surface Wa. The second handover position A2 is located on the positive X-axis and negative Y-axis side relative to the rotation center line 92 of the rotary table 91, and is used for handing over the wafer W to the second holding disk 93b during grinding of the second surface Wb.

[0051] The first processing position B1 is located on the negative X-axis and negative Y-axis side relative to the rotation center line 92 of the rotary table 91, and a first grinding unit 100 is configured there. As an example, the first grinding unit 100 grinds the first surface Wa or the second surface Wb of the wafer W held on the first holding disk 93a.

[0052] like Figure 4 As shown, the first grinding unit 100 has a grinding section 101. The grinding section 101 includes a grinding stone 102, a grinding wheel 103, a mounting member 104, a spindle 105, and a drive unit 106. The grinding wheel 103 has an annular shape and supports the grinding stone 102 on its lower surface. The mounting member 104 supports the grinding wheel 103. The spindle 105 rotates the grinding wheel 103 and the grinding stone 102 via the mounting member 104. The drive unit 106 is mounted on the spindle 105 and, for example, incorporates a motor (not shown), causing the spindle 105 to rotate. Additionally, as... Figure 1 As shown, the grinding section 101 is configured to move in the vertical direction along the support column 107 via the drive section (not shown).

[0053] The second processing position B2 is located on the negative X-axis and positive Y-axis side relative to the rotation center line 92 of the rotary table 91, and a second grinding unit 110 is configured there. As an example, the second grinding unit 110 grinds the second surface Wb or the first surface Wa of the wafer W held on the second holding disk 93b. The second grinding unit 110 has the same structure as the first grinding unit 100.

[0054] Here, as described above, the holding surfaces of the holding disks 93a and 93b have a convex shape. Therefore, in the grinding process of the wafer W using the grinding units 100 and 110, the wafer W contacts the annularly arranged grinding wheels 102 and 112 in an arc-shaped manner from its center to its outer periphery. By rotating the holding disks 93a and 93b and the grinding wheels 103 and 113 respectively in this state, the entire surface of the wafer W is ground.

[0055] Furthermore, in the grinding units 100 and 110, by adjusting the relative angle (tilt) between the holding surfaces of the holding disks 93a and 93b and the grinding surfaces of the grinding stones 102 and 112 using the aforementioned tilt adjustment mechanism 95, the shape of the ground wafer W can be controlled to be any one of a planar shape, a convex shape, a concave shape, a W-shape, an M-shape, or any combination thereof. A planar shape is one where the entire surface of the wafer W is adjusted to be below the desired thickness deviation (TTV), preferably controlled to have uniform thickness across the entire surface. A convex shape is one where the thickness of the central portion of the wafer W is greater than the thickness of the outer periphery. A concave shape is one where the thickness of the concave portion of the wafer W is less than the thickness of the outer periphery. A W-shape is one where the thickness at the radius center point is less than the thickness of both the central and outer periphery of the wafer W. An M-shape is one where the thickness at the radius center point is greater than the thickness of both the central and outer periphery of the wafer W.

[0056] Alternatively, a thickness measuring device (not shown) for measuring the thickness of the ground wafer W can be installed at the handover positions A1, A2 or the processing positions B1, B2.

[0057] At least one control device 120 is provided in the wafer processing system 1 described above. The control device 120 processes computer-executable instructions that cause the wafer processing system 1 to perform the various processes described herein. The control device 120 can be configured to control the various elements of the wafer processing system 1 to perform the various processes described herein. In one embodiment, part or all of the control device 120 may also be included in the wafer processing system 1. The control device 120 may also include a processing unit, a storage unit, and a communication interface. The control device 120 is implemented, for example, by a computer. The processing unit can be configured to perform various control actions by reading a program from the storage unit that provides logic or processes capable of performing various control actions and executing the read program. The program can be stored in the storage unit in advance or retrieved via a medium when needed. The retrieved program is stored in the storage unit and read from and executed by the processing unit. The medium can be various computer-readable storage media or a communication line connected to the communication interface. The storage medium can be transient or non-transient. The processing unit can be a CPU (Central Processing Unit) or one or more circuits. The storage unit can also include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface can also communicate with the wafer processing system 1 via a communication line such as a LAN (Local Area Network).

[0058] Next, the wafer processing performed using the wafer processing system 1 configured as described above will be explained. In this embodiment, the wafer W cut from an ingot by a wire saw or the polished wafer W is subjected to a process to improve the in-plane uniformity of thickness. In addition, in this embodiment, the case where the target shape of the wafer W after a series of processes is planar will be explained. This planar shape is a shape with uniform thickness within the wafer plane, and for example, it includes cases where both sides of the wafer W are horizontal, as well as cases where both sides are not horizontal.

[0059] First, a cassette C containing multiple wafers W is placed on the cassette mounting stage 10 of the loading / unloading station 2. The wafers W are stored in the cassette C with their first surface Wa facing upwards and their second surface Wb facing downwards. Next, the wafers W in the cassette C are removed using the wafer transport device 20 and transported to the conveyor device 30. The wafers W transported to the conveyor device 30 are then transported to the buffer device 72 using the wafer transport device 60.

[0060] Next, the wafer W is transferred to the grinding apparatus 90 using the wafer transfer device 80 and handed over to the first holding disk 93a at the first handover position A1. The second surface Wb of the wafer W is held by the first holding disk 93a.

[0061] Next, the rotary table 91 is rotated to move the wafer W to the first processing position B1. Then, the first surface Wa of the wafer W is ground using the first grinding unit 100. Figure 5 S1).

[0062] Next, the rotary table 91 is rotated to move the wafer W to the first junction position A1.

[0063] Next, the wafer W is transferred to the cleaning apparatus 70 using the wafer transfer device 80. In the cleaning apparatus 70, the first surface Wa of the wafer W is cleaned. Figure 5 (S2). In S2, the second surface Wb of wafer W can also be cleaned.

[0064] Next, the wafer W is transported to the thickness measuring device 71 using either the wafer transport device 80 or the wafer transport device 60. In the thickness measuring device 71, the thickness distribution of the wafer W is obtained by measuring the thickness of the wafer W after grinding the first surface Wa at multiple points, and the thickness deviation of the wafer W is calculated. Figure 5 (S3). The calculated thickness distribution and thickness deviation of the wafer W are output to the control device 120, for example. Alternatively, if the grinding apparatus 90 is equipped with a thickness measuring device, the thickness of the ground wafer W can also be measured using the thickness measuring device of the grinding apparatus 90.

[0065] Here, the first surface Wa in S1 is ground so that, for example, the thickness of the ground wafer W is uniform within the wafer surface and the shape of the wafer W becomes planar. However, due to factors such as wear of the grinding stone 102, parallelism between the first holding disk 93a and the grinding stone 102, and other device characteristics, the shape of the ground wafer W sometimes does not become planar.

[0066] Therefore, in the control device 120, the relative tilt (parallelism) of the first holding plate 93a and the grinding stone 102 is determined based on the thickness distribution and thickness deviation of the wafer W obtained in S3, in order to counteract the worsening trend of the thickness deviation of the wafer W. Then, the relative tilt (parallelism) of the first holding plate 93a and the grinding stone 102 is adjusted by the tilt adjustment mechanism 95. Figure 5 (S4). Hereinafter, adjusting the tilt of the first holding disk 93a in this way will be referred to as the tilt axis correction of the first holding disk 93a. In this case, it is possible to make the first surface Wa of the wafer W to be ground by the first grinding unit 100 flat, thereby suppressing the thickness deviation of the wafer W to a small extent.

[0067] Next, the wafer W is transferred to the flipping device 73 using the wafer transfer device 80. In the flipping device 73, the first surface Wa and the second surface Wb of the wafer W are flipped vertically. Figure 5 (S5). That is, the wafer W is flipped so that the first surface Wa faces downward and the second surface Wb faces upward.

[0068] Next, the wafer W is transferred to the grinding apparatus 90 using the wafer transfer device 80 and handed over to the second holding disk 93b at the second handover position A2. The second holding disk 93b is used to hold the first surface Wa of the wafer W.

[0069] Next, the rotary table 91 is rotated to move the wafer W to the second processing position B2. Then, the second surface Wb of the wafer W is ground using the second grinding unit 110. Figure 5 (S6).

[0070] Next, the rotary table 91 is rotated to move the wafer W to the second junction position A2.

[0071] Next, the wafer W is transferred to the cleaning apparatus 70 using the wafer transfer device 80. In the cleaning apparatus 70, the second surface Wb of the wafer W is cleaned. Figure 5 (S7). In S7, the first surface Wa of wafer W can also be cleaned.

[0072] Next, the wafer W is transported to the thickness measuring device 71 using either the wafer transport device 80 or the wafer transport device 60. In the thickness measuring device 71, the thickness distribution of the wafer W is obtained by measuring the thickness of the wafer W after grinding the second surface Wb at multiple points, and the thickness deviation of the wafer W is calculated. Figure 5 (S8). The calculated thickness distribution and thickness deviation of the wafer W are output to the control device 120, for example. Alternatively, if the grinding apparatus 90 is equipped with a thickness measuring device, the thickness of the ground wafer W can also be measured using the thickness measuring device of the grinding apparatus 90.

[0073] In the control device 120, the relative tilt (parallelism) of the second holding disk 93b and the grinding stone 112 is determined based on the thickness distribution and thickness deviation of the wafer W obtained in S8, and the tilt axis of the second holding disk 93b is corrected by the tilt adjustment mechanism 95. Figure 5 (S9). Furthermore, this S9 is the same as S4 described above. In this case, the second surface Wb of the wafer W to be ground by the second grinding unit 110 can be flattened, thereby suppressing the thickness deviation of the wafer W to a small extent.

[0074] Next, the wafer W is transported to the etching apparatus 40 using the wafer transport device 60. In the etching apparatus 40, the second surface Wb of the wafer W is etched using the etching solution E under predetermined etching conditions. Figure 5 (S10). In S10, the second surface Wb is etched into the target shape by etching under predetermined etching conditions.

[0075] Next, the wafer W is transferred to the flipping device 51 using the wafer transfer device 60. In the flipping device 51, the first surface Wa and the second surface Wb of the wafer W are flipped vertically. Figure 5 (S11). That is, the wafer W is flipped so that the first surface Wa faces upward and the second surface Wb faces downward.

[0076] Next, the wafer W is transported to the thickness measuring device 50 using the wafer transport device 60. In the thickness measuring device 50, the thickness distribution of the wafer W is obtained by measuring the thickness of the wafer W after etching the second surface Wb at multiple points, and the thickness deviation of the wafer W is calculated. Figure 5 (S12). The calculated thickness distribution and thickness deviation of the wafer W are output to the control device 120, for example.

[0077] In the control device 120, the optimal etching conditions for the first surface Wa are determined based on the thickness distribution and thickness deviation of the output wafer W, which optimizes the etching amount distribution in the etching process of the first surface Wa. Figure 6 (S13). In S13, the following S130~S133 are performed to determine the optimal etching conditions.

[0078] First, before performing processing on wafer W in wafer processing system 1, multiple training data sets are acquired for the optimization process described later. Figure 3 (S130). In addition, the learning data is the etching amount distribution of wafer W for a certain etching condition.

[0079] In S130, the wafer dummy is etched under several different etching conditions, for example. Specifically, the dummy's rotational speed (also called rotational speed), the scanning speed of the nozzle 43 (also called oscillation speed), and the scanning width of the nozzle 43 (refer to...) are varied during etching. Figure 6The etching of the wafer dummy is performed using the scanning width L (also known as the oscillation radius) or the number of cycles of the nozzle 43. The etching time for each wafer dummy is the same. The etching of the wafer dummy is performed similarly to the etching in S14 described later, by rotating the wafer dummy and supplying etchant E from the nozzle 43 to the wafer dummy while reciprocating the nozzle 43. In the following description, the reciprocating movement of the nozzle 43 between the two ends of the wafer dummy is defined as one cycle.

[0080] The wafer dummy is etched under various etching conditions for a predetermined desired time (desired number of cycles). Then, the etching amount distribution of the wafer dummy is acquired and output to the control device 120. Furthermore, the control device 120 compresses the output etching amount distribution under each etching condition into an etching amount distribution per unit time (unit number of cycles), and stores these compressed etching amount distributions as the aforementioned learning data.

[0081] Next, based on the thickness distribution in the target shape of the etched wafer W and the thickness distribution in the surface shape of the etched wafer W obtained in S12 (hereinafter referred to as "measured shape"), the target etching amount distribution in the etching process of S14 described later is obtained. Figure 6 (S131). As an example, the target etching amount distribution of the etching process can be obtained by calculating the difference between the thickness distribution in the target shape of the wafer W and the thickness distribution in the measured shape.

[0082] Next, an optimization method is used to optimize the superimposed learning data and the number of times the learning data is superimposed, so as to obtain the target etching amount distribution in S131 by superimposing multiple learning data. Figure 6 (S132).

[0083] In S132, for example, the control of the etching amount distribution is applied to the knapsack problem to optimize the learning data and the number of times the learning data is superimposed. For example, the etching amount distribution is the knapsack of the knapsack problem, and the learning data is the items of the knapsack problem. Moreover, the learning data and the number of times the learning data is superimposed are optimized to minimize the difference between the etching amount distribution obtained by superposition and the target etching amount distribution.

[0084] Next, the etching conditions corresponding to the optimized learning data in S132 are integrated to determine the optimal etching conditions. Figure 5 (S133). Specifically, multiple etching conditions are integrated by superimposing the optimized multiple etching conditions to determine the optimal etching condition. In other words, the optimal etching condition that optimizes the etching amount distribution is determined.

[0085] Next, the wafer W is transferred to the etching apparatus 40 using the wafer transfer device 60. In the etching apparatus 40, the first surface Wa of the wafer W is etched using the etching solution E under the optimal etching conditions determined in S13. Figure 5 (S14). In S14, the first surface Wa is etched under optimal etching conditions to optimize the etching amount distribution, thereby processing the first surface Wa into the target shape.

[0086] Next, the wafer W is transported to the thickness measuring device 50 using the wafer transport device 60. In the thickness measuring device 50, the thickness distribution of the wafer W is obtained by measuring the thickness of the wafer W after etching both the first surface Wa and the second surface Wb at multiple points. Figure 7 (S15). Furthermore, the thickness deviation of wafer W can also be calculated. The calculated thickness distribution of wafer W is output to control device 120, for example, for the processing of other wafers W to be processed by wafer processing system 1.

[0087] Afterwards, the fully processed wafer W is transferred to the cassette C of the cassette stage 10 via the transfer device 30. In this way, a series of wafer processing steps in the wafer processing system 1 are completed.

[0088] According to this embodiment, for the m-th (m is a natural number greater than or equal to 1) wafer W among multiple wafers W processed sequentially... m In S4, based on the wafer W obtained in S3 m The thickness distribution and thickness deviation are used to correct the tilt axis of the first holding disk 93a. Therefore, in S1, the subsequent (m+1)th wafer W is... m+1 When the first surface Wa is ground, it can be made flat, thereby flattening the wafer W. m+1 The thickness deviation is suppressed to a small extent. Similarly, for the m-th wafer W m In S9, based on the wafer W obtained in S8 m The thickness distribution and thickness deviation are used to correct the tilt axis of the second holding disk 93b. Therefore, for the (m+1)th wafer W m+1 The wafer W after grinding the first surface Wa in S1 is capable of... m+1 The thickness deviation is suppressed to a small extent.

[0089] Furthermore, according to this embodiment, for the m-th wafer W m In S13, based on the wafer W obtained in S12 m The optimal etching conditions for the first surface Wa are determined by the thickness distribution and thickness deviation. In this case, the wafer W is etched under optimal conditions in S14. mEtching the first surface Wa can optimize the etching amount distribution, thereby processing the first surface Wa into the target shape.

[0090] In the above embodiment, after etching the second surface Wb in S10, the first surface Wa is etched in S14, but the etching order of these surfaces can also be reversed. For example, between S7 and S8 or between S8 and S10, the first surface Wa and the second surface Wb of the wafer W are flipped in the vertical direction. That is, the wafer W is flipped so that the second surface Wb faces downward and the first surface Wa faces upward. Then, the second surface Wb is etched after the first surface Wa is etched.

[0091] In the above embodiments, an etching amount distribution was used as the etching index distribution (learning data) for controlling the etching process of wafer W, but an etching amount deviation distribution can also be used. The etching amount deviation distribution is a distribution of values ​​obtained by subtracting the average value of the etching amount within the wafer surface from the etching amount itself. In this case, the etching amount deviation distribution is used instead of the etching amount distribution when determining the optimal etching conditions in S13.

[0092] In the above embodiments, the acquisition of multiple learning data in S130 is performed in the wafer processing system 1, but it can also be performed outside the wafer processing system 1. In this case, the control device 120 determines the optimal etching conditions based on the multiple learning data acquired outside the wafer processing system 1.

[0093] Here, when processing multiple wafers W using S1 to S15, sometimes after continuously processing multiple wafers W in the first group, multiple wafers W in the second group are processed continuously at a predetermined interval. There is no particular limitation on the number of wafers W in the first and second groups, but as an example, 25 wafers in one wafer group are listed. Furthermore, in this embodiment, the last wafer W in the first group corresponds to the first substrate in this disclosure, and the first wafer W in the second group corresponds to the second substrate in this disclosure.

[0094] In the first group, the tilt axis of the first holding disk 93a is corrected for each wafer W in S4. Then, at least for the second and subsequent wafers W, when the first surface Wa is ground using the tilt-axis corrected first holding disk 93a, the first surface Wa of the ground wafer W can be flattened, and the thickness deviation of the wafer W (hereinafter referred to as "post-grinding thickness deviation") is suppressed to a small extent.

[0095] Regarding this point, in the second group, which was separated from the first group, such as Figure 7As shown in (a), when the first surface Wa of the first wafer W is ground in S1, the first surface Wa of the ground wafer W is not flat, and the thickness deviation (=De1-Dc1) of the ground wafer W is worsened. In the example shown, the shape of the ground wafer W (first surface Wa) is a concave type with a central thickness Dc1 smaller than the outer peripheral thickness De1.

[0096] Here, the heat accumulation at the processing point during grinding of the first wafer W in the second group, when the interval is separated, is mainly cited as a factor contributing to the deterioration of the thickness deviation after grinding. When the first surface Wa of the wafer W held in the first holding disk 93a is ground by the grinding unit 101, heat is generated on various axes such as the lifting shaft 97 of the tilt adjustment mechanism 95, the shaft that rotates the first holding disk 93a, and the spindle 105 of the grinding unit 101 due to the processing load.

[0097] In this regard, in the first group, since multiple wafers W are processed continuously, each axis becomes fully elongated due to heat storage, and the grinding of the first surface Wa is stable at least for the second and subsequent wafers W.

[0098] Furthermore, for the last wafer W in the first group, tilt axis correction of the first holding disk 93a is performed in S4, that is, tilt axis correction of the first holding disk 93a is performed while each axis is fully elongated due to heat storage. However, when the first surface Wa of the first wafer W is ground in the second group after the first group is separated, the lifting axis 97, the rotation axis of the first holding disk 93a, the spindle 105, and other axes shrink due to cooling. Therefore, it is sometimes impossible to properly adjust the relative tilt of the first holding disk 93a and the grinding stone 102, and the first surface Wa of the first wafer W cannot be properly ground. As a result, as described above, the thickness deviation of the wafer W deteriorates after grinding, and the shape of the wafer W becomes concave.

[0099] Furthermore, in detail, the interval is the time from the end of grinding the last wafer W of the first group to the start of grinding the first wafer W of the second group, which is a predetermined time or longer. Moreover, the predetermined time that causes the thickness deviation of the first wafer W of the second group to deteriorate after grinding depends primarily on the heat storage at the processing point. The heat storage varies due to various factors; for example, the heat storage increases when grinding multiple wafers W for a long time, and also when the load during grinding multiple wafers W is high.

[0100] In addition to the aforementioned heat storage, another factor contributing to the deterioration of the thickness deviation after grinding of the first wafer W in the second group is the change in the state of the grinding edge of the grinding stone 102. When the state of the grinding edge of the grinding stone 102 changes and deteriorates, the thickness deviation of the wafer W deteriorates after grinding.

[0101] As described above, in the state where the first wafer W of the second group is a concave shape with more grinding at the center than the target shape (planar type), the first surface Wa of the wafer W is then etched in S14. In this case, when the target thickness of the etched wafer W is set to D2, the etching amount at the center (=Dc1-D2) is smaller than the etching amount at the outer periphery (=De1-D2). Especially when the thickness deviation (recession amount) after grinding is large, the etching amount at the center of the wafer W becomes small, and it may not be possible to sufficiently remove the damage layer formed at the center.

[0102] Therefore, as Figure 8 As shown in (b), the target thickness is increased when grinding the first surface Wa of the first wafer W in the second group. In this example, the ground shape of the first wafer W is concave, so the target thickness Ec1 of the central portion of the first wafer W is greater than the target thickness of the second and subsequent wafers W. Consequently, the target thickness Ee1 of the outer periphery of the first wafer W is also greater than the target thickness of the second and subsequent wafers W. In addition, the target thickness of the second and subsequent wafers W is the same as the target thickness when grinding the first surface Wa normally.

[0103] The target thickness Ec1 at the center of the first wafer W is, for example, greater than the sum of the target thickness E2 of the subsequent etched wafer W and the damage layer. In this case, when etching the first surface Wa of the first wafer W, sufficient etching amount (=Ec1-E2) can be ensured at the center of the wafer W, and the damage layer formed in the center can be sufficiently removed. At this time, the etching amount of the first wafer W becomes greater than the etching amount of the second and subsequent wafers W.

[0104] In this embodiment, multiple wafers W are processed based on the insights obtained by the inventors through in-depth research. Specifically, firstly, the multiple wafers W to be processed are divided into multiple groups, for example, at intervals of a predetermined time or more. That is, in each group, at least the thickness deviation after grinding the first surface Wa or the second surface Wb of the first wafer W is relatively poor. Hereinafter, the case of continuously processing multiple wafers W in a group will be described. In addition, the nth (n is a natural number of 1 or more) wafer W processed in a group is referred to as wafer W. n .

[0105] like Figure 8As shown, when the first surface Wa of the first wafer W1 is ground in S1, the shape of the ground first surface Wa is concave. Next, in S4, the tilt axis of the first holding disk 93a is corrected based on the thickness distribution and thickness deviation of the ground wafer W. Therefore, for the second wafer W2, the first surface Wa is ground using the tilt-axis-corrected first holding disk 93a in S1, resulting in a flattened shape for the ground first surface Wa.

[0106] Furthermore, when the second surface Wb of wafer W1 is ground in S6, the shape of the ground second surface Wb is concave. Next, in S9, the tilt axis of the second holding disk 93b is corrected based on the thickness distribution and thickness deviation of the ground wafer W. Thus, for wafer W2, the second surface Wb is ground using the tilt axis-corrected second holding disk 93b in S6, and the shape of the ground second surface Wb becomes flat.

[0107] Here, the thickness of wafer W1 before grinding is set as T. 10 The target thickness of the central portion after grinding the first surface Wa is set as Tc. 11 Set the target thickness of the outer periphery to Te 11 The target thickness of the central portion after grinding the second surface Wb is set as Tc. 12 Set the target thickness of the outer periphery to Te 12 Additionally, the thickness of wafer W2 before grinding is set to T. 20 Let T be the target thickness after grinding the first surface Wa. 21 The target thickness after grinding the second surface Wb is set as T. 22 .

[0108] In this embodiment, the target thickness Tc of the central portion of the wafer W1 after double-sided grinding is... 12 The target thickness T after double-sided grinding of wafer W2 22 Same or greater than target thickness T 22 Large. Therefore, the target thickness Te of the outer periphery of wafer W1 after double-sided grinding is... 12 It is also greater than the target thickness T after double-sided grinding of wafer W2. 22 Large. In this case, for example, the grinding amount on both sides of wafer W1 can be less than the grinding amount on both sides of wafer W2, or the grinding amount on one side of wafer W1 can be less than the grinding amount on one side of wafer W2.

[0109] For example, when the grinding amount on both sides of wafer W1 is small, the grinding amount (=T) at the center of the first surface Wa of wafer W1 is reduced. 10 -Tc 11The grinding amount (=T) of the first surface Wa of wafer W2 20 -Tc 21 Smaller. Additionally, the grinding amount (=Tc) at the center of the second surface Wb of wafer W1 is reduced. 11 -Tc 12 It is also greater than the grinding amount (=T) of the first surface Wa of wafer W2. 21 -Tc 22 Small. In this case, it is easy to control the grinding of both sides of wafer W1 by balancing the grinding time on both sides.

[0110] Additionally, for example, when the grinding amount on one side of wafer W1 is small, the grinding amount (=T) at the center of the first surface Wa of wafer W1 is reduced. 10 -Tc 11 The grinding amount (=T) of the first surface Wa of wafer W2 20 -Tc 21 Smaller. Additionally, the grinding amount (=Tc) at the center of the second surface Wb of wafer W1 is reduced. 11 -Tc 12 The grinding amount (=T) of the first surface Wa of wafer W2 21 -Tc 22 The same applies. In this case, the consumption of the grinding stone 102 used for grinding the first surface Wa of the wafer W1 can be suppressed.

[0111] Alternatively, the grinding amount at the center of the first surface Wa of wafer W1 can be the same as the grinding amount at the first surface Wa of wafer W2, while the grinding amount at the center of the second surface Wb of wafer W1 can be less than the grinding amount at the first surface Wa of wafer W2. In this case, the consumption of the grinding stone 112 used for grinding the second surface Wb of wafer W1 can be suppressed.

[0112] Next, when the second surface Wb of wafer W1 is etched in S10, the shape of the etched second surface Wb becomes flat. Here, the target thickness of the central portion of the etched wafer W1 is set as Tc. 13 Set the target thickness of the outer periphery to Te 13 The target thickness Tc of the central portion of the wafer W1 after grinding the second surface Wb, as described above. 12 The target thickness Tc of the central part after etching 13 The combined thickness with the damaged layer is large. Therefore, when etching the second surface Wb of wafer W1, sufficient etching amount (=Tc) can be ensured even in the center of wafer W. 12 -Tc 13 This allows for the thorough removal of the damage layer formed in the central portion. At this time, the etching amount (=Tc) of the second surface Wb of wafer W1... 12 -Tc13 The etching amount of the second surface Wb of wafer W2 (=T) 22 -T 23 )many.

[0113] Furthermore, when the first surface Wa of wafer W1 is etched in S14, the shape of the etched first surface Wa becomes flat. Here, the target thickness of the etched wafer W1 is set as T. 14 The target thickness Tc of the central portion of the wafer W1 after etching the second surface Wb, as described above. 13 Compared to the target thickness T after etching 14 The combined thickness with the damaged layer is large. Therefore, when etching the second surface Wb of wafer W1, sufficient etching amount (=Tc) can be ensured even in the center of wafer W. 13 -T 14 This allows for the thorough removal of the damage layer formed in the central portion. At this time, the etching amount (=Tc) of the first surface Wa of wafer W1... 13 -T 14 The etching amount of Wa on the first surface of wafer W2 (=T) 23 -T 24 )many.

[0114] As described above, when both sides of the first wafer W1 are ground and etched, the shape of wafer W1 becomes planar, and its thickness becomes T. 14 The thickness T of wafer W1 14 The thickness T of the second wafer W2 24 Same. In addition, in the processing of the second and subsequent wafers W2 in S1 to S15, the surface shape of the wafer W2 is flat in any process after grinding (S1, S6) and etching (S10, S14) of each side.

[0115] According to the above implementation method, the target thickness Tc of the central portion after grinding both sides of wafer W1 is achieved. 12 The target thickness T after double-sided grinding of wafer W2 22 The large size ensures sufficient etching depth when etching both sides of wafer W1. As a result, the damage layer formed on both sides of wafer W1 can be properly removed.

[0116] Furthermore, in this embodiment, as described above, the target shape of the wafer W1 after a series of S1 to S15 processes is planar. This planar shape is a shape with uniform thickness within the wafer surface, including, for example, cases where both sides of the wafer W1 are horizontal, and cases where both sides are not horizontal. Figure 9As an example, the figure shows a shape in which the central portion of the first surface Wa is slightly concave compared to the outer periphery, and the central portion of the second surface Wb is slightly bulging compared to the outer periphery.

[0117] Regarding this, in the above embodiment, the second surface Wb was etched under predetermined etching conditions in S10, but these etching conditions can also be optimized. The method for determining the optimal etching conditions for the second surface Wb is the same as the method for determining the optimal etching conditions for the first surface Wa in S13. In this case, the shape of the wafer W1 after a series of S1 to S15 processes can be made into a planar type with two horizontal sides.

[0118] In the above embodiments, the first surface Wa and the second surface Wb of the first wafer W1 after grinding are respectively concave, but sometimes they are convex. In this case, as long as the target thickness Te of the outer periphery of the wafer W1 after double-sided grinding is achieved... 12 The target thickness T after double-sided grinding of wafer W2 22 Larger is sufficient. Thus, the etching amount during etching of both sides of wafer W1 can be adequately ensured, resulting in the proper removal of the damage layer formed on both sides of wafer W1.

[0119] In the above embodiments, the target thickness Tc of the central portion of the first wafer W1 after double-sided grinding is achieved. 12 The target thickness T after double-sided grinding of the second wafer W2 22 The target thickness control for double-sided grinding of wafer W1 is large, but it is not limited to the first wafer W1. For example, if the shape of the first surface Wa of the second wafer W2 after grinding is also concave, or if the shape of the second surface Wb of wafer W2 after grinding is also concave, the target thickness Tc of the central portion after double-sided grinding of wafer W2 can be controlled. 12 The target thickness T after grinding both sides of the third wafer W3 is compared. 32 Large. Therefore, the etching amount during etching of both sides of wafer W2 can be sufficiently ensured, resulting in the proper removal of the damage layer formed on both sides of wafer W2. Furthermore, in this case, during the processing of the third and subsequent wafers W3 in S1 to S15, in any process after grinding (S1, S6) and etching (S10, S14) of each side, the surface shape of wafer W3 is flat.

[0120] As mentioned above, in each group, the number of wafers W up to the nth wafer is... n The target thickness after double-sided grinding is greater than that of the (n+1)th wafer and subsequent wafers W. n+1 The target thickness after double-sided grinding is large. In this case, it is possible to fully ensure the thickness of the wafer W. nThe amount of etching performed on both sides of the wafer is such that the material formed on the wafer W can be appropriately removed. n The double-sided damage layer. Additionally, at this point, in each group, the wafer W up to the nth sheet... n The etching amount is greater than that of the (n+1)th and subsequent wafers W n+1 The etching amount is large.

[0121] In the above embodiments, when multiple wafers W to be processed are grouped into multiple groups, the grouping is based on the time interval, but the grouping basis is not limited to this. If it is anticipated that the surface shape of the first wafer W after grinding will differ from the surface shape of the second wafer W following the first wafer W after grinding, the grouping is based on the boundary between the first wafer W and the second wafer W. In this example, the first wafer W is the last wafer processed in the first group, and the second wafer W is the first wafer processed in the second group.

[0122] The situation where the surface shape of the first wafer W after grinding differs from the surface shape of the second wafer W after grinding includes cases where the target surface shape of the first wafer W and the second wafer W is intentionally altered. Additionally, it also includes cases where the surface shape differs in the first wafer W and the second wafer W due to changes in the type and thickness of the film formed on the first surface Wa and the second surface Wb.

[0123] In the above embodiments, various processing methods were described for both the first surface Wa and the second surface Wb of the wafer W. However, the techniques disclosed herein can also be applied to the processing of only one side of the wafer W. For example, when processing the first surface Wa of the wafer W, the following steps are performed sequentially: grinding of the first surface Wa (S1), cleaning of the first surface Wa (S2), thickness measurement of the wafer W (S3), tilt axis correction of the first holding disk 93a (S4), determination of the optimal etching conditions for the first surface Wa (S13), etching of the first surface Wa (S14), and thickness measurement of the wafer W (S15). In the processing of the first surface Wa of the wafer W, in S4, the tilt axis correction of the first holding disk 93a is performed based on the thickness distribution and thickness deviation of the wafer W obtained in S3, and in S13, the optimal etching conditions for the first surface Wa are determined based on the thickness distribution and thickness deviation of the wafer W.

[0124] like ​As shown, when the first surface Wa of the first wafer W1 is ground, the shape of the ground first surface Wa becomes concave. Next, the tilt axis of the first holding disk 93a is corrected based on the thickness distribution and thickness deviation of the ground wafer W. Therefore, for the second wafer W2, the first surface Wa is ground using the tilt-axis corrected first holding disk 93a, resulting in a flattened shape for the ground first surface Wa.

[0125] Here, the target thickness of the central portion after grinding the first surface Wa is set as Tc. 11 Set the target thickness of the outer periphery to Te 11 Additionally, the target thickness after grinding the first surface Wa is set as T. 21 In this embodiment, the target thickness Tc of the central portion of the wafer W1 after grinding is... 11 The target thickness T after grinding of wafer W2 21 Large. Therefore, the target thickness Te of the outer periphery of wafer W1 after grinding is... 11 It is also greater than the target thickness T of wafer W2 after grinding. 21 big.

[0126] Next, when the first surface Wa of wafer W1 is etched, the shape of the etched first surface Wa becomes flat. Here, the target thickness of the etched wafer W1 is set as T. 14 The target thickness Tc of the central portion of the above-mentioned ground wafer W1. 11 Compared to the target thickness T after etching 14 The thickness, when combined with the damaged layer, is large. Therefore, when etching the first surface Wa of wafer W1, sufficient etching amount (=Tc) can be ensured even in the center of wafer W. 11 -T 14 This allows for the thorough removal of the damage layer formed in the central portion. At this time, the etching amount (=Tc) of the first surface Wa of wafer W1... 11 -T 14 The etching amount of Wa on the first surface of wafer W2 (=T) 21 -T 24 )many.

[0127] As described above, when the first surface Wa of the first wafer W1 is ground and etched, the shape of the wafer W1 becomes planar, and its thickness becomes T. 14 The thickness T of wafer W1 14 The thickness T of the second wafer W2 24 The same applies. Furthermore, in the processing of the second and subsequent wafers W2, in any process after grinding the first surface Wa and after etching the first surface Wa, the surface shape of the wafer W2 is flat.

[0128] The same effects as those described above can be achieved in the above embodiments. That is, the target thickness Tc of the central portion after grinding the wafer W1 is increased. 11 The target thickness T after grinding wafer W2 is compared. 21 The surface is large enough to allow etching of the first surface Wa of wafer W1 to properly remove the damage layer.

[0129] In the above embodiments, the target shape of the wafer W after etching is a flat (planar) shape, but it is not limited to this. For example, the technology of this disclosure can also be applied when the target shape of the wafer W after etching is any of the following shapes: convex, concave, W-shaped, or M-shaped.

[0130] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The above embodiments can also be omitted, substituted, or modified in various ways without departing from the appended claims and their spirit. For example, the constituent elements of the above embodiments can be arbitrarily combined. Based on such arbitrary combinations, the functions and effects of each structural element involved in the combination can be obtained, and other functions and effects that are clearly known to those skilled in the art based on the description herein can be achieved.

[0131] Furthermore, the effects described in this specification are merely illustrative or exemplary and not limiting. That is to say, the technology of this invention can achieve the above-described effects and other effects clearly known to those skilled in the art based on the description in this specification, or can replace the above-described effects to achieve other effects clearly known to those skilled in the art based on the description in this specification.

[0132] Explanation of reference numerals in the attached figures

[0133] 1: Wafer processing system; 40: Etching device; 90: Grinding device; 120: Control device; W: Wafer; Wa: First surface; Wb: Second surface.

Claims

1. A substrate processing method for processing a substrate, the substrate processing method comprising the following processes: Grinding the surface of the substrate; and The surface of the ground substrate is then etched. In the substrate processing method described above, The surfaces of multiple substrates are ground and etched. Considering that the surface shape of the first substrate after grinding is expected to differ from that of the second substrate after grinding, the plurality of substrates are divided into multiple groups with the boundary between the first substrate and the second substrate as the boundary. The target thickness after grinding of the substrates up to the nth substrate in the group where the second substrate is the first substrate is greater than the target thickness after grinding of the (n+1)th substrate and thereafter, wherein... n is a natural number greater than or equal to 1.

2. The substrate processing method according to claim 1, wherein, The time from the end of grinding the first substrate to the start of grinding the second substrate is set to a predetermined time or more.

3. The substrate processing method according to claim 1, wherein, The etching amount of the substrates up to the nth substrate in the group is greater than the etching amount of the (n+1)th substrate and thereafter.

4. The substrate processing method according to claim 1 further includes the following processing: The thickness of the m-th substrate after grinding is measured, and the thickness distribution of the m-th substrate is obtained; and The relative inclination of the substrate holding portion holding the (m+1)th substrate and the grinding portion grinding the surface of the (m+1)th substrate is determined based on the thickness distribution of the m-th substrate. m is a natural number greater than or equal to 1.

5. The substrate processing method according to claim 1 further includes the following processing: The thickness of the m-th substrate after grinding is measured, and the thickness distribution of the m-th substrate is obtained; and The optimal etching conditions for the surface of the m-th substrate are determined based on the thickness distribution of the m-th substrate, wherein... m is a natural number greater than or equal to 1.

6. The substrate processing method according to claim 1 further includes the following processing: Grinding the first and second surfaces of the substrate; and The first and second surfaces of the ground substrate are etched. The target thickness of the first and second surfaces of the substrates up to the nth substrate in the group after grinding is greater than the target thickness of the first and second surfaces of the substrates from the (n+1)th substrate onwards after grinding. The grinding amount of the first surface and the grinding amount of the second surface of the substrate up to the nth substrate in the group are respectively less than the grinding amount of the first surface and the grinding amount of the second surface of the (n+1)th substrate and thereafter.

7. The substrate processing method according to claim 1, further comprising: Grinding is performed on the first and second surfaces of the substrate; as well as The first and second surfaces of the ground substrate are etched. The target thickness of the first and second surfaces of the substrates up to the nth substrate in the group after grinding is greater than the target thickness of the first and second surfaces of the substrates from the (n+1)th substrate onwards after grinding. The grinding amount of either the first surface or the second surface of the substrates up to the nth substrate in the group is less than the grinding amount of either the first surface or the second surface of the (n+1)th substrate. Make the other of the grinding amount of the first surface and the grinding amount of the second surface of the substrate up to the nth substrate in the group the same as the grinding amount of the first surface or the grinding amount of the second surface of the (n+1)th substrate and thereafter.

8. A substrate processing system for processing a substrate, the substrate processing system comprising: A grinding device that grinds the surface of a substrate; An etching apparatus that etches the surface of a ground substrate; as well as Control device, The control device performs the following controls: The surfaces of multiple substrates are ground in the grinding apparatus, and the surfaces of the multiple substrates are etched in the etching apparatus; Considering that the surface shape of the first substrate after grinding is expected to differ from the surface shape of the second substrate after grinding, the plurality of substrates are divided into multiple groups with the boundary between the first substrate and the second substrate as the boundary; and The target thickness after grinding of the substrates up to the nth substrate in the group with the second substrate as the first substrate is greater than the target thickness after grinding of the (n+1)th substrate and thereafter, where n is a natural number greater than 1.

9. The substrate processing system according to claim 8, wherein, The control device performs the following control: the time from the end of grinding the first substrate to the start of grinding the second substrate is set to a predetermined time or more.

10. The substrate processing system according to claim 8, wherein, The control device performs the following control: the etching amount of the substrates up to the nth substrate in the group is greater than the etching amount of the (n+1)th substrate and thereafter.

11. The substrate processing system according to claim 8, wherein, The substrate processing system also includes a thickness measuring device, which measures the thickness of the substrate after grinding. The grinding device has: Substrate holding portion, which holds the substrate; and The grinding section grinds the surface of the substrate held in the substrate holding section. The control device performs the following controls: The thickness of the m-th substrate after grinding is measured in the thickness measuring device, and the thickness distribution of the m-th substrate is obtained; and The relative inclination of the substrate holding portion that holds the (m+1)th substrate and the grinding portion that grinds the surface of the (m+1)th substrate is determined based on the thickness distribution of the m-th substrate, where m is a natural number greater than or equal to 1.

12. The substrate processing system according to claim 8, wherein, The substrate processing system includes a thickness measuring device, which measures the thickness of the substrate after grinding. The control device performs the following controls: The thickness of the m-th substrate after grinding is measured in the thickness measuring device, and the thickness distribution of the m-th substrate is obtained; and The optimal etching conditions for the surface of the m-th substrate are determined based on the thickness distribution of the m-th substrate, where m is a natural number greater than or equal to 1.

13. The substrate processing system according to claim 8, wherein, The control device performs the following controls: The first and second surfaces of the substrate are ground in the grinding apparatus. The first and second surfaces of the ground substrate are etched in the etching apparatus. The target thickness of the first and second surfaces of the substrates up to the nth substrate in the group after grinding is greater than the target thickness of the first and second surfaces of the substrates from the (n+1)th substrate onwards after grinding. as well as The grinding amount of the first surface and the grinding amount of the second surface of the substrate up to the nth substrate in the group are respectively less than the grinding amount of the first surface and the grinding amount of the second surface of the (n+1)th substrate and thereafter.

14. The substrate processing system according to claim 8, wherein, The control device performs the following controls: The first and second surfaces of the substrate are ground in the grinding apparatus. The first and second surfaces of the ground substrate are etched in the etching apparatus. The target thickness of the first and second surfaces of the substrates up to the nth substrate in the group after grinding is greater than the target thickness of the first and second surfaces of the substrates from the (n+1)th substrate onwards after grinding. The amount of grinding on the first surface and the amount of grinding on the second surface of the substrates up to the nth substrate in the group is less than the amount of grinding on the first surface or the amount of grinding on the second surface of the (n+1)th substrate and thereafter. as well as Make the other of the grinding amount of the first surface and the grinding amount of the second surface of the substrate up to the nth substrate in the group the same as the grinding amount of the first surface or the grinding amount of the second surface of the (n+1)th substrate and thereafter.

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