Substrate processing method and substrate processing system

Abstract

A substrate processing method for processing a substrate, the substrate processing method comprising: etching a first surface and a second surface of the substrate based on a first thickness of the substrate before etching the first surface and the second surface of the substrate, determining a first optimal etching condition by using an optimization method so that the surface shape of the first surface after etching becomes a target shape, and determining a second optimal etching condition by using the optimization method so that the surface shape of the second surface after etching becomes a target shape; the first surface is etched on the basis of the first optimal etching condition; and etching the second surface based on the second optimal etching condition.

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, which includes: 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 liquid to the ground substrate for wet etching based on the determined processing conditions to remove the damage layer formed on the surface of the substrate.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-147908 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The technology disclosed herein appropriately controls the surface shape of both sides of a substrate after etching.

[0008] Solution for solving the problem

[0009] One aspect of this disclosure is a substrate processing method for processing a substrate, the substrate processing method comprising: determining a first optimal etching condition based on a first thickness of the substrate before etching a first surface and a second surface of the substrate, using an optimization method to determine a second optimal etching condition in a manner that makes the surface shape of the etched first surface become a target shape, and determining a second optimal etching condition using an optimization method in a manner that makes the surface shape of the etched second surface become a target shape; etching the first surface based on the first optimal etching condition; and etching the second surface based on the second optimal etching condition.

[0010] The effects of the invention

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

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

[0013] Figure 2 This 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 flowchart illustrating the main processes involved in wafer processing.

[0016] Figure 5 This is an explanatory diagram showing the main processes involved in wafer processing.

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

[0018] Figure 7 This is a flowchart illustrating the main steps of the method for determining the first and second optimal etching conditions in the second mode. Detailed Implementation

[0019] In the semiconductor device manufacturing process, the cut surfaces of disk-shaped silicon wafers (hereinafter referred to as "wafers") obtained by cutting from single-crystal silicon ingots using a wire saw or similar tool are planarized and smoothed to homogenize the wafer's thickness. Planarization of the cut surfaces is performed, for example, by surface grinding or polishing. Smoothing is performed, for example, by spin etching, in which etchant is supplied from above the cut surfaces of the wafer while it is being rotated.

[0020] Patent Document 1 discloses the following: A wet etching process is performed on a ground wafer to remove the damage layer formed on the wafer surface during the grinding process. In the condition determination step described in Patent Document 1, the operation of the nozzle supplying the processing liquid, the wafer rotation speed, the supply amount of processing liquid, the supply time of processing liquid, and the type of processing liquid are determined based on the wafer thickness obtained in the measurement step, serving as the processing conditions for the wet etching process. Furthermore, in the damage layer removal step, by performing wet etching on the wafer based on the determined processing conditions, the flatness of the wafer surface is improved.

[0021] However, for example, when the target etching amount is small in the etching process, the supply time of the etching solution (processing solution) becomes shorter, and therefore the control range of the etching amount distribution based on the adjustment of processing conditions becomes smaller. Therefore, it is sometimes difficult to properly control the surface shape of the wafer after etching.

[0022] The technology disclosed herein appropriately controls the surface shape of both sides of a substrate after etching. Hereinafter, a wafer processing system as a substrate processing system and a wafer processing method as a substrate processing method 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 omitted from repeated description by using the same reference numerals.

[0023] In the wafer processing system 1 according to this embodiment, a wafer W, which serves as a substrate and is obtained by dicing from a spindle, is subjected to a process to improve the in-plane uniformity of its thickness. Hereinafter, the dicing 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.

[0024] 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. The loading / unloading station 2, for example, handles the loading and unloading of a cassette C capable of accommodating multiple wafers W between the loading / unloading station and the outside. The processing station 3 is equipped with various processing devices for performing desired processing on the wafers W.

[0025] A cassette loading stage 10, which holds multiple cassettes, such as three, 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 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 between the cassettes C of the cassette loading stage 10 and the transport device 30 described later.

[0026] At the inbound / outbound station 2, a transfer device 30 for transferring wafers W between the wafer transfer device 20 and the processing station 3 is provided adjacent to the wafer transfer device 20 on the negative X-axis direction side of the wafer transfer device 20.

[0027] 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 in the order of first processing block G1, second processing block G2, and third processing block G3 from the positive X-axis direction side (the side of the transfer station 2) to the negative direction side.

[0028] The first processing block G1 is equipped with an etching device 40, a thickness measuring device 50, a flipping device 60, and a wafer transport device 70. The etching device 40, the thickness measuring device 50, and the flipping device 60 are arranged in a stacked configuration. However, the number and arrangement of the etching device 40, the thickness measuring device 50, and the flipping device 60 are not limited thereto.

[0029] The etching apparatus 40 etches silicon (Si) on the first surface Wa or the second surface Wb after grinding by the grinding apparatus 140 (described later). Multiple etching apparatuses 40 may be provided to increase wafer processing productivity.

[0030] 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.

[0031] The wafer holding portion 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 portion 41 is not limited to the illustrated example; for instance, the wafer holding portion 41 may also include a holding disk (chuck) (not shown) that holds the wafer W from below. The wafer holding portion 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 portion 41 to rotate.

[0032] The nozzle 43 supplies etching solution E to either 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 positioned above the wafer holding portion 41 and is configured to move horizontally and vertically 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 moves back and forth (scanning movement) or rotates above the center of wafer W.

[0033] To properly etch the silicon on the wafer W, which may be the object of etching, the etching solution E contains hydrofluoric acid (HF), nitric acid (HNO3), and phosphoric acid (H3PO4). In one example, the etching solution E is a mixture containing hydrofluoric acid, nitric acid, phosphoric acid, and water. Furthermore, the object to be etched may also be, for example, amorphous silicon.

[0034] Additionally, nozzle 43 supplies FPM (hydrofluoric acid-hydrogen peroxide-water mixture) to the first surface Wa or the second surface Wb of the wafer W held in wafer holding portion 41. Nozzle 43 is connected to an FPM supply source (not shown) that supplies FPM to nozzle 43.

[0035] Figure 1 In one example, the thickness measuring device 50 shown includes a measuring unit 51 (see reference). Figure 5The thickness measuring device 50 includes a measurement unit (not shown) and a calculation unit. The measurement unit 51 is equipped with a sensor that measures 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 measurement unit 51, and calculates the flatness (TTV: Total Thickness Variation) of the wafer W. Alternatively, the calculation of the thickness distribution and flatness of the wafer W can be performed by the control device 170 (described later) instead of the calculation unit. In other words, the calculation unit (not shown) can also be provided within the control device 170 (described later). Furthermore, the structure of the thickness measuring device 50 is not limited to this and can be configured arbitrarily.

[0036] The flipping device 60 flips the first surface Wa and the second surface Wb of the wafer W in the vertical direction. The structure of the flipping device 60 is arbitrary.

[0037] The wafer transport device 70 is disposed on the negative X-axis side of the transport device 30. The wafer transport device 70 has, for example, two transport arms 71 for holding and transporting the wafer W. Each transport arm 71 is configured to be freely movable in the horizontal direction, the vertical direction, and about the horizontal and vertical axes. Moreover, the wafer transport device 70 is configured to transport the wafer W to the transport device 30, the etching device 40, the thickness measuring device 50, the flipping device 60, the first cleaning device 80 (described later), the second cleaning device 90 (described later), the thickness measuring device 100 (described later), the buffer device 110 (described later), and the flipping device 120 (described later).

[0038] The second processing block G2 is equipped with a first cleaning device 80, a second cleaning device 90, a thickness measuring device 100, a buffer device 110, a flipping device 120, and a wafer transport device 130. The first cleaning device 80, the second cleaning device 90, the thickness measuring device 100, the buffer device 110, and the flipping device 120 are arranged in a stacked configuration. Furthermore, the number and arrangement of the first cleaning device 80, the second cleaning device 90, the thickness measuring device 100, the buffer device 110, and the flipping device 120 are not limited thereto.

[0039] The first cleaning device 80 cleans at least the first surface Wa or the second surface Wb after grinding in the grinding device 140 described later. For example, from nozzle 81 (see...) Figure 5 Cleaning fluid is supplied to the first surface Wa or the second surface Wb, and the brush part 82 (refer to) Figure 5 It abuts against the second surface Wb or the first surface Wa to clean at least the first surface Wa or the second surface Wb.

[0040] The second cleaning device 90 removes metallic components adhering to the first surface Wa or the second surface Wb after cleaning in the first cleaning device 80. For example, from nozzle 91 (see reference...) Figure 5 FPM is supplied to the first surface Wa or the second surface Wb for cleaning to remove metal components.

[0041] In one example, the thickness measuring device 100 has the same structure as the thickness measuring device 50 described above. However, the structure of the thickness measuring device 100 is not limited to this and can be configured arbitrarily.

[0042] The buffer device 110 temporarily holds the unprocessed wafer W as it is transferred from the first processing block G1 to the second processing block G2. The structure of the buffer device 110 is arbitrary. In addition, the buffer device 110 may have an alignment mechanism (not shown) to adjust the center position of the wafer W relative to the holding disks 143a, 143b described later, and / or the orientation of the wafer W in the horizontal direction.

[0043] The flipping device 120 flips the first surface Wa and the second surface Wb of the wafer W in the vertical direction. The structure of the flipping device 120 is arbitrary.

[0044] The wafer transport device 130 is, for example, disposed on the positive Y-axis side of the first cleaning device 80, the second cleaning device 90, the thickness measuring device 100, the buffer device 110, and the flipping device 120. The wafer transport device 130 has, for example, two transport arms 131 that hold and transport the wafer W via an adsorption holding surface (not shown). Each transport arm 131 is supported by a multi-jointed arm member 132 and is configured to move freely in the horizontal and vertical directions, and freely about the horizontal and vertical axes. Furthermore, the wafer transport device 130 is configured to transport the wafer W to the etching device 40, the thickness measuring device 50, the flipping device 60, the first cleaning device 80, the second cleaning device 90, the thickness measuring device 100, the buffer device 110, the flipping device 120, and the grinding device 140 (described later).

[0045] A grinding device 140 is provided in the third processing block G3. The grinding device 140 grinds the first surface Wa or the second surface Wb of the wafer W to planarize it.

[0046] The grinding apparatus 140 includes a rotary table 141. The rotary table 141 is configured to rotate freely about a vertical rotation center line 142 via a rotation mechanism (not shown). Four holding disks 143a and 143b are provided on the rotary table 141 for holding and holding the wafer W. Two of the four holding disks 143a and 143b are first holding disks 143a, used for grinding at the first processing position B1 (described later). These two first holding disks 143a are arranged at a point-symmetrical position across the rotation center line 142. The remaining two second holding disks 143b are used for grinding at the second processing position B2 (described later). These two second holding disks 143b are also arranged at a point-symmetrical position across the rotation center line 142. That is, the first holding disks 143a and the second holding disks 143b are arranged alternately in the circumferential direction.

[0047] The four holding discs 143a and 143b can be moved to the transfer positions A1~A2 and the processing positions B1~B2 by rotating the rotary table 141. In addition, the four holding discs 143a and 143b are each configured to be able to rotate about a vertical axis by a rotating mechanism (not shown).

[0048] The first handover position A1 is located on the positive X-axis and positive Y-axis side relative to the rotation center line 142 of the rotary stage 141, and is used for handover of wafer W relative to the first holding disk 143a 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 142 of the rotary stage 141, and is used for handover of wafer W relative to the second holding disk 143b during grinding of the second surface Wb.

[0049] The first processing position B1 is located on the negative X-axis and negative Y-axis side relative to the rotation center line 142 of the rotary table 141, and a first grinding unit 150 is disposed there. The first grinding unit 150 has a grinding section 151, which has a ring-shaped and rotatable grinding stone (not shown). In addition, the grinding section 151 is configured to be movable in the vertical direction along the support column 152. As an example, the first grinding unit 150 grinds the first surface Wa or the second surface Wb of the wafer W held on the first holding disk 143a.

[0050] The second processing position B2 is located on the negative X-axis and positive Y-axis side relative to the rotation center line 142 of the rotary table 141, and a second grinding unit 160 is disposed there. The second grinding unit 160 has a grinding section 161, which has a ring-shaped and rotatable grinding stone (not shown). In addition, the grinding section 161 is configured to be able to move in the vertical direction along the support column 162. As an example, the second grinding unit 160 grinds the second surface Wb or the first surface Wa of the wafer W held on the second holding disk 143b.

[0051] In addition, a thickness measuring device (not shown) for measuring the thickness of the ground wafer W can also be installed at the handover positions A1, A2 or the processing positions B1, B2.

[0052] The wafer processing system 1 described above is provided with at least one control device 170. The control device 170 processes computer-executable commands that cause the wafer processing system 1 to perform the various processes described herein. The control device 170 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 170 may also be included in the wafer processing system 1. The control device 170 may also include a processing unit, a storage unit, and a communication interface. The control device 170 is implemented, for example, by a computer. The processing unit can be configured to read a program from the storage unit that provides logic or routines capable of performing various control actions, and perform various control actions by executing the read program. The program may 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 the storage unit by the processing unit and executed. The medium may be various computer-readable storage media or a communication line connected to the communication interface. The storage medium may be a transient storage medium or a non-transient storage medium. The processing unit can be a CPU (Central Processing Unit) or one or more circuits. The storage unit can 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 communicate with the wafer processing system 1 via a communication line such as a LAN (Local Area Network).

[0053] 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 the ingot using a wire saw or the like, or the polished wafer W, is subjected to a process to improve the in-plane uniformity of its thickness.

[0054] First, a cassette C containing multiple wafers W is placed on the cassette mounting stage 10 of the loading / unloading station 2. In the cassette C, the wafers W are stored with their first surface Wa facing upwards and their second surface Wb facing downwards. Next, the wafers W in the cassette C are removed by the wafer transport device 20 and transported to the conveyor device 30. The wafers W transported to the conveyor device 30 are then transferred by the wafer transport device 70 to the buffer device 110.

[0055] Next, wafer W is transferred from wafer transport device 70 to flipping device 60. In flipping device 60, the first surface Wa and the second surface Wb of wafer W are flipped in the vertical direction. Figure 4 and Figure 5 (S1). That is, the wafer W is flipped so that the second surface Wb faces upward and the first surface Wa faces downward.

[0056] Next, wafer W is transferred from wafer transport device 130 to grinding device 140 and placed on second holding disk 143b at second transfer position A2. On second holding disk 143b, the first surface Wa of wafer W is held. Then, rotary table 141 is rotated to move wafer W to second processing position B2. Furthermore, the second surface Wb of wafer W is ground by second grinding unit 160. Figure 4 and Figure 5 (S2). Next, the rotary table 141 is rotated to move the wafer W to the second junction position A2.

[0057] Next, wafer W is transferred by wafer transport device 130 to first cleaning device 80. In first cleaning device 80, cleaning fluid is supplied from nozzle 81 to the second surface Wb to clean the second surface Wb, and the first surface Wa is cleaned by brush 82. Figure 4 and Figure 5 (S3).

[0058] Next, wafer W is transferred from wafer transport device 130 to flipping device 120. In flipping device 120, the first surface Wa and the second surface Wb of wafer W are flipped in the vertical direction. Figure 4 and Figure 5 (S4). That is, the wafer W is flipped so that the first surface Wa faces upward and the second surface Wb faces downward.

[0059] Next, wafer W is transferred by wafer transport device 130 to grinding device 140 and handed over to first holding disk 143a at first handover position A1. On first holding disk 143a, the second surface Wb of wafer W is held and held. Then, rotary table 141 is rotated to move wafer W to first processing position B1. Furthermore, the first surface Wa of wafer W is ground by first grinding unit 150. Figure 4 and Figure 5 (S5). Next, the rotary table 141 is rotated to move the wafer W to the first junction position A1.

[0060] Next, wafer W is transferred by wafer transport device 130 to thickness measuring device 100. In thickness measuring device 100, the thickness distribution of wafer W is obtained by measuring the thickness of the first surface Wa and the second surface Wb at multiple points using measuring unit 101. Figure 4 and Figure 5 (S6). Furthermore, the flatness of wafer W can also be calculated. The obtained thickness distribution of wafer W is output to control device 170, for example, and is used in the processing of other wafers W to be processed in wafer processing system 1. Additionally, when a thickness measuring device is provided in grinding apparatus 140, the thickness of the ground wafer W can also be measured by the thickness measuring device of grinding apparatus 140.

[0061] Next, wafer W is transferred by wafer transport device 130 to first cleaning device 80. In first cleaning device 80, cleaning fluid is supplied from nozzle 81 to first surface Wa to clean the first surface Wa, and the second surface Wb is cleaned by brush 82. Figure 4 and Figure 5 (S7).

[0062] Next, wafer W is transferred from wafer transport device 130 to flipping device 120. In flipping device 120, the first surface Wa and the second surface Wb of wafer W are flipped in the vertical direction. Figure 4 and Figure 5 (S8). That is, the wafer W is flipped so that the second surface Wb faces upward and the first surface Wa faces downward.

[0063] Next, wafer W is transferred by wafer transport device 130 to second cleaning device 90. In second cleaning device 90, FPM is supplied from nozzle 91 to second surface Wb to clean the second surface Wb and remove the metal components adhering to the second surface Wb. Figure 4 and Figure 5 (S9).

[0064] Next, wafer W is transferred from wafer transport device 130 to flipping device 120. In flipping device 120, the first surface Wa and the second surface Wb of wafer W are flipped in the vertical direction. Figure 4 and Figure 5 (S10). That is, the wafer W is flipped so that the first surface Wa faces upward and the second surface Wb faces downward.

[0065] Next, wafer W is transported to thickness measuring device 50 by wafer transport device 130 or wafer transport device 70. In thickness measuring device 50, the thickness distribution of wafer W is obtained by measuring the thickness of the first surface Wa and the second surface Wb at multiple points using measuring unit 51, and the flatness of wafer W is calculated. Figure 4 and Figure 5 (S11). In the thickness measuring apparatus 50, for example, the thickness of the wafer W is measured by the measuring unit 51 while the second surface Wb is held on a holding disk (not shown). At this time, the metal components have been removed from the second surface Wb by S9, so contamination of the holding disk can be suppressed, thereby allowing for proper subsequent thickness measurement of the wafer W. The thickness distribution and flatness of the wafer W obtained by S11 are output to the control device 170, for example. Furthermore, the thickness of the wafer W measured by S11 is equivalent to the first thickness in this disclosure.

[0066] In the control device 170, based on the thickness distribution and flatness of the output wafer W, the first optimal etching condition for the etching process of the first surface Wa and the second optimal etching condition for the etching process of the second surface Wb are determined. Figure 4 (S12). The first optimal etching condition is the condition that optimizes the etching amount distribution when etching the first surface Wa in S13 (described later). The second optimal etching condition is the condition that optimizes the etching amount distribution when etching the second surface Wb in S15 (described later). Furthermore, the method for determining the first and second optimal etching conditions in the control device 170 will be described later.

[0067] Next, wafer W is transferred from wafer transport device 70 to etching device 40. In etching device 40, the first surface Wa of wafer W is etched under the first optimal etching conditions determined in S12. Figure 4 and Figure 5 (S13). In S13, the wafer W held in the wafer holding section 41 is rotated, and while the nozzle 43 is reciprocated, etchant E is supplied from the nozzle 43 to the first surface Wa to etch the first surface Wa. Moreover, by etching the first surface Wa under the first optimal etching conditions, the etching amount distribution is optimized, and the first surface Wa is processed into the target shape.

[0068] In addition, in S13, after etching the first surface Wa with the etching solution E, FPM is supplied from the nozzle 43 to the first surface Wa to clean the first surface Wa and remove the metal components of the first surface Wa.

[0069] Next, wafer W is transferred from wafer transport device 70 to flipping device 60. In flipping device 60, the first surface Wa and the second surface Wb of wafer W are flipped in the vertical direction. Figure 4 and Figure 5 (S14). That is, the wafer W is flipped so that the second surface Wb faces upward and the first surface Wa faces downward.

[0070] Next, wafer W is transferred by wafer transport device 70 to etching device 40. In etching device 40, the second surface Wb of wafer W is etched under the second optimal etching conditions determined in S12. Figure 4 and Figure 5 (S15). In S13, the wafer W held in the wafer holding section 41 is rotated, and while the nozzle 43 is reciprocated, etchant E is supplied from the nozzle 43 to the second surface Wb to etch the second surface Wb. Moreover, by etching the second surface Wb under the second optimal etching conditions, the etching amount distribution is optimized, and the second surface Wb is processed into the target shape.

[0071] In addition, in S15, after etching the second surface Wb with the etchant E, FPM is supplied from the nozzle 43 to the second surface Wb to clean the second surface Wb.

[0072] Next, wafer W is transferred from wafer transport device 70 to flipping device 60. In flipping device 60, the first surface Wa and the second surface Wb of wafer W are flipped in the vertical direction. Figure 4 and Figure 5 (S16). That is, the wafer W is flipped so that the first surface Wa faces upward and the second surface Wb faces downward.

[0073] Next, wafer W is transferred from wafer transport device 70 to thickness measuring device 50. In thickness measuring device 50, the thickness distribution of wafer W is obtained by measuring the thickness of the first surface Wa and the second surface Wb at multiple points using measuring unit 51. Figure 4 and Figure 5 (S17). Furthermore, the flatness of wafer W can also be calculated. The obtained thickness distribution of wafer W is output to control device 170, for example, and this thickness distribution is used for the processing of other wafers W to be processed in wafer processing system 1.

[0074] Afterwards, the wafer W, having undergone all processing, is transferred via the transfer device 30 to the cassette C of the cassette stage 1. In this way, the series of wafer processing steps in the wafer processing system 1 is completed.

[0075] Next, the method for determining the first and second optimal etching conditions described above ( Figure 4 S12 will be explained below. For example, there are two modes for determining the first and second optimal etching conditions. Below, we will use... Figure 6 The flowchart is used to illustrate the first mode. Figure 7 The flowchart is used to illustrate the second mode.

[0076] In the first mode, firstly, before processing the wafer W in the wafer processing system 1, multiple training data sets to be used in the optimization process described later are acquired. Figure 6 (S120). In addition, the learning data is the etch amount distribution (etch profile) of wafer W relative to a certain etch condition.

[0077] In S120, wafer dummy wafers are etched under several different etching conditions, for example. The etching of each wafer dummy wafer is performed similarly to the etching processes in S13 and S15, by rotating the wafer dummy wafer and supplying etchant E to the wafer dummy wafer through the nozzle 43 while the nozzle 43 reciprocates (scanning movement). In the following description, the reciprocating movement of the nozzle 43 between the two ends of the wafer dummy wafer is defined as one cycle. Specifically, in S120, for example, the rotational speed of the wafer dummy wafer during etching (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. Figure 3 The scanning width L, also known as the oscillation radius, or the number of cycles of nozzle 43, is used to etch the dummy wafers. In this case, the etching processing time for each dummy wafer is the same.

[0078] For etching of dummy wafers under various etching conditions, an etching amount distribution is obtained and output to the control device 170. Furthermore, in the control device 170, the output etching amount distribution under each etching condition is compressed into an etching amount distribution per unit time (unit number of cycles), and the compressed etching amount distribution is used as the aforementioned learning data storage.

[0079] 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 ground wafer W (hereinafter referred to as the "measured shape") obtained in S11, the first target etching amount distribution and the second target etching amount distribution are obtained. Figure 6(S121). The first target etching amount distribution is the target etching amount distribution when etching the first surface Wa in S13. The second target etching amount distribution is the target etching amount distribution when etching the second surface Wb in S15. The method for obtaining the first and second target etching amount distributions is arbitrary. For example, regarding the first and second target etching amount distributions, a predetermined value such as a minimum etching amount can be set as a constraint condition. Moreover, the first and second target etching amount distributions are obtained based on the constraint condition by calculating the difference between the thickness distribution of the target shape of the wafer W and the thickness distribution of the measured shape. For example, when the first target etching amount distribution is 1.5 μm and the second target etching amount distribution is 1.5 μm, the target etching amount distribution (the above difference) is 3.0 μm. Furthermore, the constraint condition can also be a condition other than the etching amount distribution, such as the flatness of the target shape of the wafer W.

[0080] Next, multiple learning data are superimposed, and an optimization method is used to optimize the learning data used for superposition and the number of superpositions of the learning data in a manner that becomes the first target etching amount distribution and the second target etching amount distribution obtained in S121. Figure 6 (S122).

[0081] In S122, for example, the number of times the learning data and the learning data are superimposed is optimized by applying the control of the etching amount distribution to the knapsack problem. 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 number of times the learning data and the learning data are superimposed is optimized in a way that minimizes the difference between the superimposed etching amount distribution and the first target etching amount distribution and the second target etching amount distribution.

[0082] Next, the etching conditions corresponding to the learning data optimized in S122 are integrated to determine the first optimal etching condition and the second optimal etching condition. Figure 6 (S123). Specifically, multiple etch conditions are integrated in such a way that multiple selected etch conditions are performed in an optimized stacking manner to determine the first optimal etch condition and the second optimal etch condition.

[0083] In the second mode, prior to processing wafer W in wafer processing system 1, multiple training data sets to be used in the optimization process described later are acquired. Figure 7 (S220). The method for acquiring learning data in S220 is the same as the method for acquiring learning data in S120 of the first mode.

[0084] Next, based on the thickness distribution in the target shape of the etched wafer W and the thickness distribution in the measured shape of the ground wafer W obtained in S11, the first target etching amount distribution when etching the first surface Wa in S13 is obtained. Figure 7 (S221). The method for obtaining the first target etching amount distribution in S221 is the same as the method for obtaining the first target etching amount distribution in S121 of the first mode. For example, when the first target etching amount distribution is 1.5 μm and the second target etching amount distribution is 1.5 μm, the target etching amount distribution (the above difference) is 3.0 μm.

[0085] Next, multiple learning data are superimposed, and an optimization method is used to optimize the learning data used for superposition and the number of superpositions of the learning data in a manner that becomes the first target etching amount distribution obtained in S221. Figure 7 (S222). In S222, for example, similar to S122 of the first mode, the knapsack problem is used to optimize the number of times the learning data and the learning data are superimposed.

[0086] Next, the etching conditions corresponding to the most optimized learning data in S222 are integrated to determine the first optimal etching condition. Figure 7 (S223). The method for determining the first optimal etching condition in S223 is the same as the method for determining the first optimal etching condition in S123 of the first mode.

[0087] Next, based on the first optimal etching conditions determined by S223, the thickness distribution of the wafer W when the first surface Wa is etched is estimated. Figure 7 (S224). In S224, for example, the thickness distribution of wafer W is estimated by subtracting the etching amount distribution of the first surface Wa, which is optimally obtained in S221 to S223, from the thickness distribution of wafer W obtained in S11. Furthermore, the thickness of wafer W estimated in S224 is comparable to the second thickness in this disclosure.

[0088] Next, based on the thickness distribution in the target shape of the etched wafer W and the thickness distribution of the wafer W estimated in S224, the second target etching amount distribution is obtained when etching the second surface Wb in S15. Figure 7 (S225). The method for obtaining the second target etching amount distribution in S225 is the same as the method for obtaining the second target etching amount distribution in S121 of the first mode.

[0089] Next, multiple learning data are superimposed, and an optimization method is used to optimize the learning data used for superposition and the number of superpositions of the learning data in a manner that becomes the second target etching amount distribution obtained in S225. Figure 7(S226). In S226, similar to S122 of the first mode, for example, a knapsack problem is used to optimize the number of times the learning data and the learning data are superimposed.

[0090] Next, the etching conditions corresponding to the most optimized learning data in S226 are integrated to determine the second optimal etching conditions. Figure 7 (S227). The method for determining the second optimal etching condition in S227 is the same as the method for determining the second optimal etching condition in S123 of the first mode.

[0091] Here, when the first and second target etching amount distributions are small, the supply time of the etchant E becomes shorter, thus reducing the control range of the etching amount distribution based on the etching conditions. For example, when using the knapsack problem as the optimization method, the capacity of the knapsack (etching amount distribution) becomes smaller.

[0092] Regarding this, in either the first or second mode of this embodiment, the first and second optimal etching conditions are determined based on the thickness distribution of the wafer W obtained in S11. That is, the etching conditions for both the first surface Wa and the second surface Wb are optimized. Moreover, in the case of performing two-sided etching as in this embodiment, the etching amount is twice that of single-sided etching. In this case, even if the first and second target etching amount distributions are small, the etching amount distributions for the first surface Wa and the second surface Wb can be optimized respectively. As a result, the surface shape of the wafer W after etching can be appropriately controlled.

[0093] Furthermore, in the first mode, the first optimal etching condition and the second optimal etching condition are simultaneously determined based on the thickness distribution of the wafer W obtained in S11. In this case, in a single optimization calculation, both the etching of the first surface Wa and the etching of the second surface Wb are considered, thus enabling the determination of the first optimal etching condition and the second optimal etching condition with high precision.

[0094] Furthermore, in the second mode, the first optimal etching condition is determined based on the thickness distribution of wafer W obtained in S11, and then the second etching condition is determined based on the optimized etching amount distribution of the first surface Wa. That is, in the second mode, two optimization calculations are performed to determine the first optimal etching condition and the second optimal etching condition. In this case, fewer optimal etching conditions are determined in each optimization calculation, thus enabling calculations to be performed in a short time.

[0095] Furthermore, in the second mode, after the first optimal etching conditions are determined in S221-S223, the following can be performed in parallel: in S13, the first surface Wa is etched under the first optimal etching conditions; and in S224-S227, the second optimal etching conditions are determined. In this case, the wafer processing productivity can be improved.

[0096] 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. In this case, the etching amount deviation distribution is used instead of the etching amount distribution when determining the first optimal etching condition and the second optimal etching condition.

[0097] In the above embodiments, the acquisition of multiple learning data in S120 and S220 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 170 determines the first optimal etching condition and the second optimal etching condition based on the multiple learning data acquired outside the wafer processing system 1.

[0098] In the above embodiments, the order of the series of wafer processing steps is not limited to the above embodiments. For example, after grinding (S2) and cleaning (S3) of the second surface Wb, grinding (S5) and cleaning (S7) of the first surface Wa are performed, but grinding and cleaning of the second surface Wb can also be performed after grinding and cleaning of the first surface Wa. Furthermore, after etching (S13) of the first surface Wa, etching of the second surface Wb is performed (S15), but etching of the first surface Wa can also be performed after etching of the second surface Wb. In this case, in S9, FPM is supplied to the first surface Wa to clean the first surface Wa and remove the metal components adhering to the first surface Wa. Alternatively, in S9, both removal of the metal components from the first surface Wa and removal of the metal components from the second surface Wb can be performed.

[0099] In the above embodiments, the target shape of the etched wafer W is not limited. For example, the target shape can be any one of planar, convex, concave, W-shaped, M-shaped, or any combination of two of these, and the technology disclosed herein can still be applied. A planar shape is a shape in which the entire surface of the wafer W is adjusted to a desired flatness (TTV) or less, and preferably the thickness is uniformly controlled throughout the surface. A convex shape is a shape in which the thickness at the central portion of the wafer W is greater than the thickness at the outer periphery. A concave shape is a shape in which the thickness at the concave portion of the wafer W is less than the thickness at the outer periphery. A W-shaped shape is a shape in which the thickness at the radial center point is smaller than the thickness at the central and outer periphery of the wafer W. An M-shaped shape is a shape in which the thickness at the radial center point is larger than the thickness at the central and outer periphery of the wafer W.

[0100] In the above-described wafer processing system 1, FPM is supplied to at least one of the first surface Wa or the second surface Wb in the second cleaning apparatus 90 to remove the metal components. However, the removal of the metal components can also be performed by the etching apparatus 40. In this case, the second cleaning apparatus 90 is omitted.

[0101] It should be considered that the embodiments disclosed herein are illustrative and not restrictive in all respects. The above embodiments may 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 constituent element involved in the combination can be obtained, and other functions and effects that are clear to those skilled in the art according to the description herein can be obtained.

[0102] Furthermore, the effects described in this specification are merely illustrative or exemplary and not limiting. That is, the technology disclosed herein can achieve the aforementioned effects and other effects that are readily apparent to those skilled in the art based on the description in this specification, or the technology disclosed herein can achieve other effects that are readily apparent to those skilled in the art based on the description in this specification to replace the aforementioned effects.

[0103] Explanation of reference numerals in the attached figures

[0104] 1: Wafer processing system; 40: Etching device; 170: 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: Based on the first thickness of the substrate before etching the first and second surfaces of the substrate, a first optimal etching condition is determined by using an optimization method to make the surface shape of the first surface after etching the target shape, and a second optimal etching condition is determined by using an optimization method to make the surface shape of the second surface after etching the target shape. The first surface is etched based on the first optimal etching conditions; as well as The second surface is etched based on the second optimal etching conditions.

2. The substrate processing method according to claim 1, wherein, Based on the first thickness, an optimization method is used to simultaneously determine the first optimal etching condition and the second optimal etching condition.

3. The substrate processing method according to claim 1, wherein, The substrate processing method includes: Based on the first thickness, the first optimal etching conditions are determined using an optimization method. Based on the first optimal etching conditions, estimate the second thickness of the substrate after etching the first surface; and Based on the second thickness, an optimization method is used to determine the second optimal etching conditions.

4. The substrate processing method according to claim 3, wherein, The following processes are performed in parallel in the substrate processing method: The first surface is etched based on the first optimal etching conditions; and Determine the second optimal etching condition.

5. The substrate processing method according to claim 1, wherein, When determining the first optimal etching conditions and the second optimal etching conditions, the target etching amount of the first surface and the target etching amount of the second surface are set as constraints.

6. The substrate processing method according to claim 1, wherein, The substrate processing method includes: Grinding is performed on the first surface and the second surface; At least one of the first and second surfaces of the ground substrate is cleaned to remove metallic components; and The first thickness of the cleaned substrate was measured.

7. A substrate processing system for processing a substrate, the substrate processing system comprising: Etching apparatus for etching the surface of a substrate; and Control device, in, The control device performs the following controls: Based on the first thickness of the substrate before etching the first and second surfaces of the substrate, a first optimal etching condition is determined by using an optimization method to make the surface shape of the first surface after etching the target shape, and a second optimal etching condition is determined by using an optimization method to make the surface shape of the second surface after etching the target shape. In the etching apparatus, the first surface is etched based on the first optimal etching conditions; as well as In the etching apparatus, the second surface is etched based on the second optimal etching conditions.

8. The substrate processing system according to claim 7, wherein, The control device performs the following control: based on the first thickness, it uses an optimization method to simultaneously determine the first optimal etching conditions and the second optimal etching conditions.

9. The substrate processing system according to claim 7, wherein, The control device performs the following controls: Based on the first thickness, the first optimal etching conditions are determined using an optimization method. Based on the first optimal etching conditions, the second thickness of the substrate after etching the first surface is estimated; as well as Based on the second thickness, an optimization method is used to determine the second optimal etching conditions.

10. The substrate processing system according to claim 9, wherein, The control device performs the following processes in parallel: The first surface is etched in the etching apparatus based on the first optimal etching conditions; and Determine the second optimal etching condition.

11. The substrate processing system according to claim 7, wherein, When determining the first optimal etching conditions and the second optimal etching conditions, the control device executes control that sets the target etching amount of the first surface and the target etching amount of the second surface as constraints.

12. The substrate processing system according to claim 7, wherein, The substrate processing system has: A grinding device that grinds the surface of a substrate; A cleaning device that cleans the surface of a ground substrate to remove metallic components; as well as A thickness measuring device for measuring the thickness of a cleaned substrate. The control device performs the following controls: In the grinding apparatus, the first surface and the second surface are ground; In the cleaning apparatus, at least one of the first surface and the second surface of the ground substrate is cleaned to remove metallic components; as well as In the thickness measuring device, the first thickness of the cleaned substrate is measured.

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