Substrate processing method and substrate processing system

Abstract

To improve productivity according to an etching processing of a substrate.SOLUTION: A substrate processing method for processing a substrate, contains steps of: reducing a thickness of the substrate; measuring a thickness of the substrate after the reduction of the thickness at a plurality of measuring points to acquire a measurement thickness of the substrate; determining an etching condition of the substrate on the basis of a difference value between the measurement thickness of the substrate and a target thickness of the substrate; removing a half amount of the difference value by etching one surface of the substrate under the determined etching condition; and removing the half amount of the difference value by etching the other surface of the substrate under the etching condition similar to that of the one surface.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a substrate processing method and a substrate processing system. [Background technology]

[0002] Patent Document 1 discloses a method for manufacturing a semiconductor wafer, which includes a step of flat-grinding wafers obtained by slicing a semiconductor ingot, and a step of etching the front and back surfaces of the wafers after flat-grinding by spin etching. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-135464 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology according to the present disclosure improves productivity in etching processes for substrates. [Means for solving the problem]

[0005] One aspect of the present disclosure is a substrate processing method for processing a substrate, the method comprising: thinning the substrate; measuring a thickness of the thinned substrate at a plurality of measurement points to obtain a measured thickness of the substrate; determining etching conditions for the substrate based on a difference value between the measured thickness of the substrate and a target thickness of the substrate; etching one surface of the substrate under the determined etching conditions to remove an amount half the difference value; Identical Etching the other surface of the substrate under the etching conditions to remove half of the difference value. [Effects of the Invention]

[0006] According to the present disclosure, productivity in etching a polished substrate can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view showing an outline of the configuration of a wafer processing system. [Figure 2] FIG. 1 is a side view showing an outline of the configuration of an etching apparatus. [Figure 3] FIG. 10 is an explanatory diagram showing a state in which the nozzle moves in the radial direction. [Figure 4] FIG. 2 is a side view showing an outline of the configuration of a grinding unit. [Figure 5] FIG. 1 is a flow diagram showing the main steps of wafer processing. [Figure 6] 1A to 1C are explanatory views showing main steps of wafer processing. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the manufacturing process of semiconductor devices, the cut surfaces of disk-shaped silicon wafers (hereinafter simply referred to as "wafers") obtained by cutting a single crystal silicon ingot using a wire saw or the like are flattened and smoothed to make the wafers uniform in thickness. The flattening of the cut surfaces is carried out, for example, by surface grinding or lapping. The smoothing of the cut surfaces is carried out, for example, by spin etching, in which an etching solution is supplied from above the cut surfaces of the wafer while the wafer is rotating.

[0009] The above-mentioned Patent Document 1 discloses that at least the front surface of a wafer obtained by slicing a semiconductor ingot is flattened by surface grinding, and then the front surface is etched by spin etching.

[0010] As disclosed in Patent Document 1, wafers obtained by slicing a semiconductor ingot are subjected to surface grinding and etching in sequence to achieve a uniform thickness. However, particularly when surface grinding and etching are performed on the front and back surfaces of a wafer, if the etching conditions for the front and back surfaces are different, there is a risk of a difference in the processing time for the front and back surfaces, resulting in reduced productivity. In other words, if the system simultaneously performs the etching process on the front surface of one wafer and the etching process on the back surface of another wafer, the etching processes for the respective wafers will not end at the same time, which can result in reduced productivity.

[0011] The technology disclosed herein has been made in consideration of the above circumstances, and aims to improve productivity in substrate etching processing. Hereinafter, a wafer processing system as a substrate processing system and a wafer processing method as a substrate processing method according to the present embodiment will be described with reference to the drawings. Note that in this specification and the drawings, elements having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0012] In the wafer processing system 1 according to this embodiment, a wafer W serving as a substrate obtained by slicing an ingot is subjected to processing to improve the in-plane thickness uniformity. Hereinafter, the slicing surface of the wafer W will be referred to as a first surface Wa as one surface, and a second surface Wb as the other surface. The first surface Wa is the surface opposite the second surface Wb. The first surface Wa and the second surface Wb may be collectively referred to as the surface of the wafer W.

[0013] 1, the wafer processing system 1 has a configuration in which a loading / unloading station 10 and a processing station 11 are integrally connected. The loading / unloading station 10 loads / unloads a cassette C, which can accommodate a plurality of wafers W, between the station and the outside, for example. The processing station 11 is equipped with various processing devices that perform desired processing on the wafers W.

[0014] The carry-in / out station 10 is provided with a cassette placement table 20. In the illustrated example, the cassette placement table 20 is configured so that a plurality of cassettes C, for example, two cassettes C, can be placed on the cassette placement table 20 in a line in the Y-axis direction.

[0015] For example, three processing blocks G1 to G3 are provided in the processing station 11. The first processing block G1, the second processing block G2, and the third processing block G3 are arranged in this order from the negative side of the X axis (the loading / unloading station 10 side) to the positive side.

[0016] The first processing block G1 is provided with reversing devices 30 and 31, a thickness measuring device 40, etching devices 50 and 51, and a wafer transfer device 60. The reversing device 30 and the etching device 50 are arranged side by side in this order from the negative side to the positive side of the X-axis. The reversing devices 30 and 31 and the thickness measuring device 40 are stacked in this order, for example, vertically from the bottom up. The etching devices 50 and 51 are stacked in this order, for example, vertically from the bottom up. The wafer transfer device 60 is arranged on the positive side of the Y-axis from the etching devices 50 and 51. Note that the number and arrangement of the reversing devices 30 and 31, thickness measuring devices 40, etching devices 50 and 51, and wafer transfer device 60 are not limited to these.

[0017] The reversing devices 30 and 31 vertically reverse (reverse) the first surface Wa and the second surface Wb of the wafer W. The reversing devices 30 and 31 may have any configuration.

[0018] In one example, the thickness measurement device 40 includes a measurement unit (not shown) and a calculation unit (not shown). The measurement unit includes a sensor that measures the thickness of the wafer W at multiple points after grinding or etching. The calculation unit acquires the thickness distribution of the wafer W from the measurement results (thickness of the wafer W) by the measurement unit, and further calculates the flatness (TTV: Total Thickness Variation) of the wafer W. Note that the calculation of the thickness distribution and flatness of the wafer W may be performed by the control device 140 described below instead of the calculation unit. In other words, a calculation unit (not shown) may be provided within the control device 140 described below. Note that the configuration of the thickness measurement device 40 is not limited to this and may be configured as desired.

[0019] The etching devices 50 and 51 etch silicon (Si) on the first surface Wa after grinding or the second surface Wb after grinding in the processing device 110 described below.

[0020] 2, etching apparatuses 50 and 51 have a wafer holder 52, a rotation mechanism 53, and a nozzle 54 as an etching liquid supply unit. Wafer holder 52 holds the outer edge of wafer W at multiple points, three points in this embodiment. The configuration of wafer holder 52 is not limited to the example shown in the figure; for example, wafer holder 52 may include a chuck that suction-holds wafer W from below. Rotation mechanism 53 rotates wafer W held by wafer holder 52 about a vertical rotation center line 52a.

[0021] The nozzle 54 supplies the etching liquid E to the first surface Wa or the second surface Wb of the wafer W held by the wafer holder 52. The nozzle 54 is connected to an etching liquid supply source (not shown) that supplies the etching liquid E to the nozzle 54. The nozzle 54 is provided above the wafer holder 52 and configured to be movable in the horizontal and vertical directions by a movement mechanism 55. In one example, the nozzle 54 is configured to be able to move back and forth (scan movement) through a rotation center line 52a of the wafer holder 52, that is, above the center of the wafer W as shown in FIG. 3 .

[0022] The etching solution E contains at least hydrofluoric acid or nitric acid to properly etch silicon of the wafer W, which may be an etching target. The etching solution E may also contain phosphoric acid or sulfuric acid.

[0023] 1, the wafer transfer device 60 has, for example, two transfer arms 61 that hold and transfer a wafer W. Each transfer arm 61 is configured to be movable horizontally, vertically, around a horizontal axis, and around a vertical axis. The wafer transfer device 60 is configured to be able to transfer the wafer W to the cassette C on the cassette mounting table 20, the inverting devices 30 and 31, the thickness measuring device 40, the etching devices 50 and 51, the buffer device 70 (described later), the cleaning device 80 (described later), and the inverting device 90 (described later).

[0024] The second processing block G2 is provided with a buffer apparatus 70, a cleaning apparatus 80, an inverting apparatus 90, and a wafer transfer apparatus 100. The buffer apparatus 70, the cleaning apparatus 80, and the inverting apparatus 90 are stacked in this order, for example, vertically from the bottom up. The wafer transfer apparatus 100 is disposed on the negative Y-axis side of the buffer apparatus 70, the cleaning apparatus 80, and the inverting apparatus 90. Note that the number and arrangement of the buffer apparatus 70, the cleaning apparatus 80, the inverting apparatus 90, and the wafer transfer apparatus 100 are not limited to this.

[0025] The buffer device 70 temporarily holds unprocessed wafers W that are transferred from the first processing block G1 to the second processing block G2. The buffer device 70 may have any configuration.

[0026] The cleaning device 80 cleans the first surface Wa or the second surface Wb after grinding by the processing device 110, which will be described later. For example, a brush is brought into contact with the first surface Wa or the second surface Wb to clean the first surface Wa or the second surface Wb. Note that a pressurized cleaning liquid may be used to clean the first surface Wa or the second surface Wb. Furthermore, the cleaning device 80 may be configured to be able to simultaneously clean the first surface Wa and the second surface Wb when cleaning the wafer W.

[0027] The reversing device 90 reverses the first surface Wa and the second surface Wb of the wafer W in the vertical direction, similar to the reversing devices 30 and 31. The reversing device 90 may have any configuration.

[0028] The wafer transfer device 100 has, for example, two transfer arms 101 that hold and transfer a wafer W. Each transfer arm 101 is configured to be movable horizontally, vertically, around a horizontal axis, and around a vertical axis. The wafer transfer device 100 is configured to be able to transfer the wafer W to the etching devices 50 and 51, the buffer device 70, the cleaning device 80, the inversion device 90, and a processing device 110, which will be described later.

[0029] The third processing block G3 is provided with processing devices 110. However, the number and arrangement of the processing devices 110 are not limited to this.

[0030] The processing apparatus 110 has a rotary table 111. The rotary table 111 is configured to be rotatable about a vertical rotation center line 112 by a rotation mechanism (not shown). Four chucks 113 for suction-holding a wafer W are provided on the rotary table 111. Of the four chucks 113, two first chucks 113a are chucks used for grinding at a first processing position B1. These two first chucks 113a are arranged in positions symmetrical with respect to a point across the rotation center line 112. The remaining two second chucks 113b are chucks used for grinding at a second processing position B2. These two second chucks 113b are also arranged in positions symmetrical with respect to a point across the rotation center line 112. That is, the first chucks 113a and the second chucks 113b are arranged alternately in the circumferential direction.

[0031] A porous chuck, for example, is used as the chuck 113. The surface of the chuck 113, i.e., the surface for holding the wafer W, has a convex shape in which the center protrudes compared to the edges when viewed from the side. Note that although this protrusion in the center is very small, in FIG. 4, the protrusion in the center of the chuck 113 is exaggerated for clarity of explanation.

[0032] As shown in FIG. 4, the chuck 113 is held by a chuck base 114. The chuck base 114 is provided with a tilt adjustment unit 115 that adjusts the relative tilt between the chuck 113 and grinding wheels 121 and 131 provided in each of the grinding units 120 and 130, which will be described later. The tilt adjustment unit 115 has a fixed shaft 116 provided on the underside of the chuck base 114 and multiple, for example, two, lift shafts 117. Each lift shaft 117 is configured to be extendable and retractable, and lifts and lowers the chuck base 114. The tilt adjustment unit 115 can tilt the chuck 113 and the chuck base 114 by vertically lifting and lowering the other end of the chuck base 114 using the lift shaft 117, with one end of the outer periphery of the chuck base 114 (a position corresponding to the fixed shaft 116) as a base point. This makes it possible to adjust the relative inclination between the surface of the chuck 113 and the surfaces of the grinding wheels 121 and 131 provided in the grinding units 120 and 130 at the processing positions B1 to B2, which will be described later.

[0033] 1, the four chucks 113 can be moved to delivery positions A1-A2 and processing positions B1-B2 by rotating the rotary table 111. Furthermore, each of the four chucks 113 is configured to be rotatable around a vertical axis by a rotation mechanism (not shown).

[0034] The first transfer position A1 is a position on the negative X-axis side and the positive Y-axis side of the turntable 111, where the wafer W is transferred to the first chuck 113a when the first surface Wa is ground. The second transfer position A2 is a position on the negative X-axis side and the negative Y-axis side of the turntable 111, where the wafer W is transferred to the second chuck 113b when the second surface Wb is ground.

[0035] The first processing position B1 is a position on the X-axis positive side and the Y-axis negative side of the turntable 111, and a first grinding unit 120 is disposed there. The first grinding unit 120 grinds the first surface Wa or the second surface Wb of the wafer W held by the first chuck 113a. The second processing position B2 is a position on the X-axis positive side and the Y-axis positive side of the turntable 111, and a second grinding unit 130 is disposed there. The second grinding unit 130 grinds the second surface Wb or the first surface Wa of the wafer W held by the second chuck 113b.

[0036] A thickness measuring device (not shown) for measuring the thickness of the wafer W after grinding may be provided at the delivery positions A1, A2 or the processing positions B1, B2.

[0037] 4, the first grinding unit 120 has a grinding wheel 122 with an annular grinding stone 121 on its underside, a mount 123 that supports the grinding wheel 122, a spindle 124 that rotates the grinding wheel 122 via the mount 123, and a drive unit 125 that incorporates, for example, a motor (not shown). The first grinding unit 120 is configured to be movable in the vertical direction along a support column 126 shown in FIG.

[0038] The second grinding unit 130 has a configuration similar to that of the first grinding unit 120. That is, the second grinding unit 130 has a grinding wheel 132 with an annular grinding stone 131, a mount 133, a spindle 134, a drive unit 135, and a support 136.

[0039] The wafer processing system 1 described above is provided with a control device 140 as shown in Fig. 1. The control device 140 is, for example, a computer equipped with a CPU, a memory, etc., and has a program storage unit (not shown). The program storage unit stores a program for controlling the processing of wafers W in the wafer processing system 1. The program may be recorded on a computer-readable storage medium H and installed from the storage medium H into the control device 140. The storage medium H may be temporary or non-temporary.

[0040] Next, a description will be given of wafer processing performed using the wafer processing system 1 configured as described above. In this embodiment, a wafer W that has been cut from an ingot using a wire saw or the like and then lapped is subjected to processing to improve the in-plane thickness uniformity.

[0041] First, a cassette C containing a plurality of wafers W is placed on the cassette mounting table 20 of the loading / unloading station 10. The wafers W are stored in the cassette C with their first surfaces Wa facing upward and their second surfaces Wb facing downward. Next, the wafer transfer device 60 removes the wafers W from the cassette C and transfers them to the buffer device 70.

[0042] Next, the wafer W is transferred to the processing device 110 by the wafer transfer device 100 and transferred to the first chuck 113a at the first transfer position A1. The second surface Wb of the wafer W is held by suction on the first chuck 113a.

[0043] Next, the turntable 111 is rotated to move the wafer W to the first processing position B1. Then, the first grinding unit 120 grinds the first surface Wa of the wafer W (step S1 in FIG. 5). The grinding conditions for the first surface Wa in step S1 are not particularly limited, but it is desirable to determine the grinding conditions such that the wafer W after grinding the second surface Wb in step S4 described below has at least improved flatness and a uniform in-plane thickness compared to the wafer W before the grinding process.

[0044] Next, the turntable 111 is rotated to move the wafer W to the first transfer position A1. At the first transfer position A1, the first surface Wa of the wafer W after grinding may be cleaned by a cleaning unit (not shown).

[0045] Next, the wafer W is transferred to the cleaning apparatus 80 by the wafer transfer apparatus 100. In the cleaning apparatus 80, the first surface Wa and the second surface Wb of the wafer W are cleaned (step S2 in FIG. 5).

[0046] Next, the wafer W is transferred to the reversing device 90 by the wafer transfer device 100. In the reversing device 90, the first surface Wa and the second surface Wb of the wafer W are reversed upside down (step S3 in FIG. 5). That is, the wafer W is reversed so that the first surface Wa faces downward and the second surface Wb faces upward.

[0047] Next, the wafer W is transferred to the processing device 110 by the wafer transfer device 100 and transferred to the second chuck 113b at the second transfer position A2. The first surface Wa of the wafer W is held by suction on the second chuck 113b.

[0048] Next, the rotary table 111 is rotated to move the wafer W to the second processing position B2. Then, the second surface Wb of the wafer W is ground by the second grinding unit 130 (step S4 in FIG. 5).

[0049] Next, the turntable 111 is rotated to move the wafer W to the second transfer position A2. At the second transfer position A2, the second surface Wb of the wafer W after grinding may be cleaned by a cleaning unit (not shown).

[0050] Next, the wafer W is transferred to the cleaning apparatus 80 by the wafer transfer apparatus 100. In the cleaning apparatus 80, the second surface Wb and the first surface Wa of the wafer W are cleaned (step S5 in FIG. 5).

[0051] Next, the wafer W is transported by the wafer transport device 60 to the thickness measurement device 40. The thickness measurement device 40 measures the thickness of the wafer W after both the first surface Wa and the second surface Wb have been ground at a plurality of measurement points within the surface of the wafer W (step S6 in FIG. 5). Note that if the processing device 110 is provided with a thickness measurement device, the thickness of the wafer W after grinding may be measured by the thickness measurement device of the processing device 110.

[0052] In step S6, the thickness measuring device 40 measures the thickness of the wafer W after double-side grinding at multiple points to obtain the thickness distribution of the wafer W after grinding, and further calculates the flatness of the wafer W. The calculated thickness distribution and flatness of the wafer W are output to, for example, the control device 140. The calculated thickness distribution and flatness of the wafer W may be fed back to the grinding process for another wafer W to be processed next in the wafer processing system 1. That is, based on the calculated thickness distribution and flatness of the wafer W, the grinding conditions for the other wafer W may be corrected so that the amount of grinding for the other wafer W is increased in the thicker portions and decreased in the thinner portions.

[0053] Furthermore, the control device 140 determines the etching amount distribution of the wafer W in the subsequent etching process of the first surface Wa and the second surface Wb from the output thickness distribution and flatness of the wafer W (step S7 in FIG. 5). Note that in the embodiment, the "etching amount" of the wafer W refers to the thickness of the wafer W removed by the subsequent etching process, and is also referred to as the removal amount.

[0054] 6(a), first, the difference [T(n)-Tg] between the actual thickness T(n) of the wafer W measured by the thickness measuring device 40 in step S6 and the target thickness of the wafer W after etching (the final thickness, hereinafter referred to as the "target thickness Tg") is calculated at the plurality of measurement points. The calculated difference between the actual thickness T(n) and the target thickness Tg is the total amount of thickness to be removed by the subsequent etching process.

[0055] Next, as shown in FIG. 6(b), the calculated difference is divided in half, [(T(n)−Tg) / 2], and the resulting value is determined as the etching amount for each of the first surface Wa and the second surface Wb in the subsequent etching process. In other words, the etching amount for each of the first surface Wa and the second surface Wb is determined to be half the total thickness to be removed by the etching process. As a result, in the subsequent etching process, the etching amount for the first surface Wa and the second surface Wb is equal, [(T(n)−Tg) / 2], and the etching for the first surface Wa and the second surface Wb can be performed under the same conditions and for the same processing time.

[0056] Subsequently, the control device 140 determines the etching conditions for the wafer W based on the etching amount distribution determined in step St7 (step S8 in FIG. 5). 3, during the etching process of the subsequent wafer W, the nozzle 54 continues to discharge the etching solution E from the nozzle 54, while moving back and forth (scanning) the nozzle 54 above the rotation center of the wafer W, i.e., passing through the rotation center line 52a, with the rotation center line 52a as the midpoint. Hereinafter, this type of etching may be referred to as "scan etching."

[0057] Therefore, the etching conditions for the wafer W determined in step S8 include the rotation speed of the wafer W, the scan speed of the nozzle 54, the scan width of the nozzle 54, the scan-out position of the nozzle 54, and the like during such scan etching. Here, the scanning speed of the nozzle 54 refers to the horizontal movement speed when the nozzle 54 is reciprocated during the etching process. The scanning width of the nozzle 54 is the distance between one turning point and the opposite turning point of the reciprocating movement of the nozzle 54 during the etching process (see symbol L in FIG. 3). The scan-out position of the nozzle 54 is the radial position at which the discharge of the etching liquid E from the nozzle 54 ends.

[0058] Once the etching conditions for the wafer W have been determined, the wafer W is then transferred by the wafer transfer device 60 to the etching device 51. In the etching device 51, as shown in FIG. 6(c), the second surface Wb of the wafer W is etched with the etching solution E using the etching amount [(T(n)−Tg) / 2] determined in step S7 and under the etching conditions determined in step S8 (step S9 in FIG. 5).

[0059] In step S9, first, the wafer W is held by the wafer holder 52 with the second surface Wb facing upward (toward the nozzle 54). Next, the wafer holder 52 (wafer W) is rotated about the vertical rotation center line 52a, and the discharge of the etching solution E from the nozzle 54 begins, thereby starting etching of the second surface Wb.

[0060] When etching the second surface Wb, as described above, the etching solution E continues to be ejected from the nozzle 54, while the nozzle 54 is moved back and forth (scanned) above the center of rotation of the wafer W, i.e., passing through the rotation center line 52a, with the rotation center line 52a as the midpoint, thereby scan-etching the wafer W.

[0061] When the etching process under the etching conditions determined in step S8 is completed, the supply of etching solution E from nozzle 54 is stopped, and second surface Wb of wafer W is rinsed with pure water and then shaken off to dry. Thereafter, rotation of wafer holder 52 (wafer W) is stopped, and etching of wafer W is completed.

[0062] Next, the wafer W is transferred to the reversing device 31 by the wafer transfer device 60. In the reversing device 31, the first surface Wa and the second surface Wb of the wafer W are reversed upside down (step S10 in FIG. 5). That is, the wafer W is reversed so that the first surface Wa faces upward and the second surface Wb faces downward.

[0063] Next, the wafer W is transferred to the etching apparatus 50 by the wafer transfer apparatus 60. In the etching apparatus 50, as shown in FIG. 6(d), the first surface Wa of the wafer W is etched with the etching solution E at the etching amount [(T(n)−Tg) / 2] determined in step S7 and under the etching conditions determined in step S8 (step S11 in FIG. 5).

[0064] In step S11, the first surface Wa is etched in the same manner as the second surface Wb in step S9. That is, first, the wafer W is held by the wafer holder 52 with the first surface Wa facing upward. Next, the wafer holder 52 (wafer W) is rotated, and the discharge of the etching solution E from the nozzle 54 begins, thereby starting etching of the first surface Wa. Thereafter, while continuing to discharge the etching solution E from the nozzle 54, the nozzle 54 is moved back and forth (scanned) with the rotation center line 52a as the midpoint, as shown in FIG. 3, to etch the first surface Wa.

[0065] Furthermore, in step S11, the first surface Wa is etched under the same conditions and with the same etching amount as the etching of the second surface Wb in step S9. This allows the time required for etching the first surface Wa and the time required for etching the second surface Wb to be unified, significantly improving the productivity of the wafer processing system 1. More specifically, for example, when etching the first surface Wa of one wafer W and etching the second surface Wb of another wafer W simultaneously, there is no waiting time for the wafer W inside or outside the wafer processing system 1, improving the throughput of the etching processes. Furthermore, there is no need to change the etching conditions between the etching of the first surface Wa and the etching of the second surface Wb, making it easier to control the etching processes.

[0066] Next, the wafer W is transferred by the wafer transfer device 60 to the thickness measurement device 40. The thickness measurement device 40 measures the thickness of the wafer W after etching on both the first surface Wa and the second surface Wb (step S12 in FIG. 5).

[0067] In step S12, the thickness measurement device 40 measures the thickness of the wafer W after double-side etching at multiple measurement points to obtain the thickness distribution of the wafer W after etching, and further calculates the flatness of the wafer W. The calculated thickness distribution and flatness of the wafer W are output to, for example, the control device 140. As an example, they may be used for processing another wafer W to be processed next in the wafer processing system 1.

[0068] Thereafter, the wafer W that has undergone all the processing is transferred by the wafer transfer device 60 to the cassette C on the cassette mounting table 20. This completes the series of wafer processing in the wafer processing system 1. Note that the wafer W that has undergone processing in the wafer processing system 1 may be polished outside the wafer processing system 1.

[0069] According to the above embodiment, the thickness distribution of the wafer W after the front and back surface grinding processes is measured, and the total thickness of the wafer W to be removed by the subsequent etching process (the difference between the measured thickness and the target value) is calculated. Then, the total thickness is equally divided and the etching amount (removal amount) for the first surface Wa and the second surface Wb is determined. In other words, the etching conditions are determined so that the removal amount (removal thickness) of the wafer W during the etching process of the first surface Wa is equal to the removal amount (removal thickness) of the wafer W during the etching process of the second surface Wb. This allows the etching process time for the first surface Wa and the etching process time for the second surface Wb to be equal, thereby improving productivity in the wafer processing system 1.

[0070] Furthermore, since the etching conditions for the subsequent etching process of the first surface Wa and the second surface Wb are determined from the thickness distribution and flatness of the wafer W after double-side grinding in step S6, the in-plane distribution of the etching amount can be optimized.

[0071] Furthermore, since the above-described series of wafer processes is performed on each wafer W, the surface shape of the etched wafer W can be controlled on a wafer-by-wafer basis.

[0072] In the above embodiment, as shown in FIG. 6 , the etching amount distribution of the wafer W is calculated based on each of the actual measured values ​​T(n) of the thickness of the wafer W at the multiple points measured in step S6, that is, the etching amount at each of the multiple measurement points is different. However, the method for determining the etching amount distribution of the wafer W is not limited to this.

[0073] Furthermore, in the above embodiments, an example has been described in which various processes are performed on a wafer W that has been cut from an ingot using a wire saw or the like and then lapped. However, the technology disclosed herein can be applied to any case in which etching processes are performed on both the front and back surfaces of a wafer W.

[0074] Furthermore, in the above embodiment, the wafer W is thinned by a grinding process, but the method for thinning the wafer W is not particularly limited. For example, a modified layer (not shown) may be formed inside the wafer W to be processed by laser processing, and the wafer W may be thinned by separation using the modified layer as a base point. In this case, the wafer processing system 1 is provided with a laser processing device (not shown) for forming the modified layer (not shown) and a separation device (not shown) for separating the wafer W using the modified layer as a base point, instead of the processing device 110. The laser processing device (not shown) and the separation device (not shown) may be configured independently or integrally.

[0075] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0076] 1. Wafer Processing System 40 Thickness measuring device 50, 51 Etching equipment 110 Processing equipment 140 Control device Tg target thickness T(n) measured thickness W wafer

Claims

1. A substrate processing method for processing a substrate, comprising: thinning the substrate; measuring a thickness of the substrate after thinning at a plurality of measurement points to obtain a measured thickness of the substrate; determining etching conditions for the substrate based on a difference value between the measured thickness of the substrate and a target thickness of the substrate; Etching one surface of the substrate under the determined etching conditions to remove half of the difference value; etching the other surface of the substrate under the same etching conditions as those for the one surface to remove half of the difference value.

2. calculating a difference between the measured thickness and the target thickness at each of the plurality of measurement points; 2. The substrate processing method according to claim 1, wherein the removal amounts of the one surface and the other surface by the etching are determined based on the difference values ​​at each of the plurality of measurement points.

3. During etching of the substrate, the etching liquid supply unit is moved back and forth above the center of rotation of the substrate while continuing to discharge the etching liquid from the etching liquid supply unit; 3. The substrate processing method according to claim 1, wherein the etching conditions for the substrate include at least one of a rotation speed when rotating the substrate, a scan speed when reciprocating the etching liquid supply unit, and a scan width when reciprocating the etching liquid supply unit.

4. thinning the substrate includes: grinding the one surface of the substrate; The substrate processing method according to claim 3 , further comprising: grinding the other surface of the substrate.

5. thinning the substrate includes: forming a modified layer within the substrate; The substrate processing method according to claim 3 , further comprising: separating the substrate into one surface side and the other surface side at the modified layer.

6. A substrate processing system for processing a substrate, a thinning device for thinning the substrate; a thickness measuring device for measuring the thickness of the substrate; an etching apparatus that etches the substrate by supplying an etching solution from an etching solution supply unit while rotating the substrate and reciprocating the etching solution supply unit in a radial direction passing through a center of the substrate; a control device; The control device controlling the thinning of the substrate; performing control to determine etching conditions for the substrate based on a difference value between a measured thickness of the substrate obtained by measuring the thickness of the substrate after thinning at a plurality of measurement points using the thickness measuring device and a target thickness of the substrate; Etching one surface of the substrate under the determined etching conditions to perform control to remove half of the difference value; and performing control to etch the other surface of the substrate under the same etching conditions as those for the one surface, thereby removing half of the difference value.

7. The control device A control for calculating a difference value between the measured thickness and the target thickness at each of the plurality of measurement points; 7. The substrate processing system according to claim 6, further comprising: a control for determining the removal amounts by etching of the one surface and the other surface based on the difference values ​​at each of the plurality of measurement points.

8. The control device 8. The substrate processing system according to claim 6, wherein the etching conditions for the substrate are at least one of a rotation speed when rotating the substrate, a scan speed when reciprocating the etching liquid supply unit, and a scan width when reciprocating the etching liquid supply unit, and the etching processing of the substrate in the etching apparatus is controlled using these at least one of these.

9. The thinning device includes: a first grinding unit that grinds the one surface of the substrate; The substrate processing system according to claim 8 , further comprising: a second grinding unit configured to grind the other surface of the substrate.

10. The thinning device includes: a laser irradiation unit that forms a modified layer inside the substrate; The substrate processing system according to claim 8 , further comprising: a separation unit that separates the substrate into one surface side and another surface side using the modified layer as a base point.

Images