Substrate processing method, substrate processing device, and computer storage medium

Abstract

This substrate processing method for processing a substrate comprises: grinding the surface of the substrate so as to achieve a grinding target shape; determining a target etching amount distribution on the basis of the grinding target shape and a predetermined final target shape; etching the ground surface of the substrate on the basis of the target etching amount distribution; and determining whether etching the surface of the substrate having the grinding target shape will result in the final target shape.

Description

SUBSTRATE PROCESSING METHOD, SUBSTRATE PROCESSING APPARATUS, AND COMPUTER STORAGE MEDIUM

[0001] The present disclosure relates to a substrate processing method, a substrate processing apparatus, and a computer storage medium.

[0002] Patent Document 1 discloses a method for manufacturing a semiconductor wafer, which includes a step of planarizing at least the front surface of a wafer obtained by slicing a semiconductor ingot, and a step of supplying an etching solution to the surface of the wafer from a nozzle while rotating the wafer and moving the nozzle back and forth in a radial direction passing through the center of the wafer, thereby etching the surface.

[0003] International Publication No. 2023 / 219026

[0004] The technology according to the present disclosure appropriately controls the surface shape of a substrate when grinding and etching the surface of the substrate.

[0005] One aspect of the present disclosure is a substrate processing method for processing a substrate, comprising: grinding a surface of the substrate to a grinding target shape; determining a target etching amount distribution based on the grinding target shape and a predetermined final target shape; etching the ground surface of the substrate based on the target etching amount distribution; and determining whether the surface of the substrate having the grinding target shape will become the final target shape by etching.

[0006] According to the present disclosure, the surface shape of a substrate can be appropriately controlled when grinding and etching the surface of the substrate.

[0007] 1 is a plan view showing an outline of the configuration of a wafer processing system; FIG. 2 is a side view showing an outline of the configuration of an etching apparatus; FIG. 3 is an explanatory diagram showing how a nozzle moves in a radial direction; FIG. 4 is a side view showing an example of the configuration of a grinding unit and a chuck; FIG. 5 is an explanatory diagram showing how a wafer is ground; FIG. 6 is a vertical sectional view showing a schematic outline of the configuration of a grinding water supply mechanism and a grinding auxiliary water supply mechanism; FIG. 7 is an explanatory diagram showing an example of a display panel; FIG. 8 is a flow diagram showing main steps of a wafer processing; FIG. 9 is a sectional view showing an example of a wafer shape after grinding; FIG. 10 is a sectional view showing another example of a wafer shape after grinding; FIG. 11 is a flow diagram showing main steps of a method for determining optimal etching conditions; FIG. 12 is a flow diagram showing main steps of a method for determining a grinding target shape; FIG. 13 is a flow diagram showing main steps of a judgment method; FIG. 14 is a sectional view showing an outline of a judgment method for a wafer having a first target shape; FIG. 15 is a sectional view showing an outline of a judgment method for a wafer having a second target shape; FIG. 16 is an explanatory diagram showing a final target shape and a shape after etching of a wafer according to an embodiment; FIG. 17 is an explanatory diagram showing a shape of a wafer after grinding according to an embodiment; FIG. 18 is an explanatory diagram showing a shape of a wafer after grinding according to an embodiment;

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

[0009] Patent Document 1 proposes a method of etching a wafer surface by supplying an etching solution from a nozzle to the wafer surface while rotating the wafer and moving the nozzle back and forth (scanning) in a radial direction passing through the center of the wafer (hereinafter referred to as "scan etching"). In scan etching, the etching solution is supplied to the center of the wafer while generating a flow of the etching solution on the wafer surface at the center, thereby controlling the wafer surface shape. In this case, it is proposed to optimize the etching amount distribution in order to control the etched wafer to have a target shape. In optimizing the etching amount distribution, it is proposed to perform an optimization calculation based on the thickness distribution in the target shape of the wafer after etching and the thickness distribution in the measured shape of the wafer after grinding, thereby obtaining the target etching amount distribution for the etching process.

[0010] Regarding such scan etching, the inventors have conducted extensive research into optimizing the etching profile for various combinations of the target shape of the etched wafer and the measured shape of the ground wafer. As a result, they have found that, among these combinations, conventional grinding and etching techniques cannot produce a target shape after etching even when the above-mentioned etching amount distribution is optimized. In particular, they have found that the margin for shape optimization by etching is relatively narrow in the peripheral region of the substrate, and that there are post-grinding shapes in which the shape of the peripheral region cannot be made into the target shape by optimizing the etching amount distribution. Therefore, with such combinations, there is room for improvement in etching a ground wafer having a certain surface shape to produce the desired target shape.

[0011] The technology disclosed herein appropriately grinds and etches the surface of a substrate. 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 a wafer processing system 1 serving as a substrate processing apparatus according to this embodiment, processing is performed on a wafer W serving as a substrate obtained by cutting from an ingot, in order to improve the in-plane thickness uniformity. Hereinafter, the cut surfaces of the wafer W will be referred to as a first surface Wa and a second surface Wb. The first surface Wa is the surface opposite the second surface Wb. The first surface Wa and the second surface Wb may also be collectively referred to as the surfaces of the wafer W.

[0013] 1, the wafer processing system 1 has a configuration in which a loading / unloading station 2 and a processing station 3 are integrally connected. In the loading / unloading station 2, for example, a cassette C capable of accommodating a plurality of wafers W is loaded and unloaded between the loading / unloading station 2 and the outside. The processing station 3 is equipped with various processing devices that perform desired processing on the wafers W.

[0014] The loading / unloading station 2 is provided with a cassette mounting table 10 on which a plurality of cassettes C, for example, three cassettes C, are mounted. A wafer transfer device 20 is provided adjacent to the cassette mounting table 10 on the negative side of the X-axis of the cassette mounting table 10. The wafer transfer device 20 is configured to be movable on a transfer path 21 extending in the Y-axis direction. The wafer transfer device 20 also has, for example, two transfer arms 22 that hold and transfer wafers W. Each transfer arm 22 is configured to be movable horizontally, vertically, around a horizontal axis, and around a vertical axis. The configuration of the transfer arms 22 is not limited to this embodiment and may have any configuration. The wafer transfer device 20 is configured to be able to transfer wafers W to the cassettes C on the cassette mounting table 10 and to a transition device 30, which will be described later.

[0015] In the loading / unloading station 2 , a transition device 30 for transferring the wafer W to and from the processing station 3 is provided adjacent to the wafer transfer device 20 on the negative side of the X axis of the wafer transfer device 20 .

[0016] For example, three processing blocks G1 to G3 are provided in the processing station 3. The first processing block G1, the second processing block G2, and the third processing block G3 are arranged in this order from the positive side of the X axis (the side of the loading / unloading station 2) to the negative side.

[0017] The first processing block G1 is provided with an etching device 40, a thickness measuring device 50, a reversing device 51, and a wafer transport device 60. The etching device 40, thickness measuring device 50, and reversing device 51 as an etching section are arranged in a stacked configuration. Note that the number and arrangement of the etching devices 40, thickness measuring devices 50, and reversing devices 51 are not limited to this.

[0018] The etching device 40 etches silicon (Si) on the first surface Wa or the second surface Wb after grinding by the grinding device 90 described below. In order to improve the throughput of wafer processing, a plurality of etching devices 40 may be provided.

[0019] As shown in FIG. 2, the etching device 40 includes a wafer holder 41 , a rotating mechanism 42 , a nozzle 43 , and a moving mechanism 44 .

[0020] The wafer holding unit 41 holds the outer edge of the wafer W at multiple points, three points in this embodiment. The configuration of the wafer holding unit 41 is not limited to the example shown in the figure, and for example, the wafer holding unit 41 may include a chuck (not shown) that suction-holds the wafer W from below. The wafer holding unit 41 is configured to be rotatable about a vertical rotation center line 41a by a rotation mechanism 42, thereby allowing the wafer W held on the wafer holding unit 41 to rotate.

[0021] The nozzle 43 supplies the etching liquid E to the first surface Wa or the second surface Wb of the wafer W held by the wafer holder 41. The nozzle 43 is connected to an etching liquid supply source (not shown) that supplies the etching liquid E to the nozzle 43. The nozzle 43 is provided above the wafer holder 41 and configured to be movable in the horizontal and vertical directions by a movement mechanism 44. In one example, the nozzle 43 is configured to be capable of reciprocating movement (scan movement) or swiveling along a rotation center line 41 a of the wafer holder 41, i.e., above the center of the wafer W as shown in FIG. 3 .

[0022] The etching solution E contains hydrofluoric acid (HF), nitric acid (HNO３ ) and phosphoric acid (H ３ P.O. ４ In one example, the etching solution E is a mixed solution containing hydrofluoric acid, nitric acid, phosphoric acid, and water. The etching target may be, for example, amorphous silicon.

[0023] 1 includes, in one example, 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 after etching at multiple points. The calculation unit acquires the thickness distribution of the wafer W from the measurement results (thickness of the wafer W) obtained 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 a control device 150 (described later) instead of the calculation unit. In other words, a calculation unit (not shown) may be provided within the control device 150 (described later). Note that the configuration of the thickness measurement device 50 is not limited to this and may be configured arbitrarily.

[0024] The reversing device 51 vertically reverses the first surface Wa and the second surface Wb of the wafer W. The reversing device 51 may have any configuration.

[0025] The wafer transfer device 60 is disposed on the negative side of the transition device 30 in the X-axis direction. 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 transition device 30, the etching device 40, the thickness measurement device 50, the inversion device 51, the cleaning device 70 described below, the thickness measurement device 71 described below, the buffer device 72 described below, and the inversion device 73 described below.

[0026] The second processing block G2 is provided with a cleaning device 70, a thickness measuring device 71, a buffer device 72, an inverting device 73, and a wafer transfer device 80. The cleaning device 70, the thickness measuring device 71, the buffer device 72, and the inverting device 73 are arranged in a stacked configuration. Note that the number and arrangement of the cleaning devices 70, the thickness measuring devices 71, the buffer device 72, and the inverting device 73 are not limited to this.

[0027] The cleaning device 70 cleans at least the first surface Wa or the second surface Wb after grinding by the grinding device 90 described below.

[0028] In one example, the thickness measuring device 71 has the same configuration as the above-described thickness measuring device 50. However, the configuration of the thickness measuring device 71 is not limited to this, and can be configured arbitrarily.

[0029] The buffer device 72 temporarily holds unprocessed wafers W that are transferred from the first processing block G1 to the second processing block G2. The configuration of the buffer device 72 is optional. The buffer device 72 may also include an alignment mechanism (not shown) that adjusts the center position of the wafer W relative to chucks 93 a, 93 b (described later) and / or the horizontal orientation of the wafer W.

[0030] The reversing device 73 vertically reverses the first surface Wa and the second surface Wb of the wafer W. The reversing device 73 may have any configuration.

[0031] The wafer transfer device 80 is disposed, for example, on the Y-axis positive side of the cleaning device 70, the thickness measurement device 71, the buffer device 72, and the inverting device 73. The wafer transfer device 80 has, for example, two transfer arms 81 that suction-hold and transport the wafer W using a suction-holding surface (not shown). Each transfer arm 81 is supported by an articulated arm member 82 and is configured to be movable horizontally, vertically, around a horizontal axis, and around a vertical axis. The wafer transfer device 80 is configured to be able to transport the wafer W to the etching device 40, the thickness measurement device 50, the inverting device 51, the cleaning device 70, the thickness measurement device 71, the buffer device 72, the inverting device 73, and a grinding device 90, which will be described later.

[0032] The third processing block G3 is provided with a grinding device 90 as a grinding unit. The grinding device 90 grinds and flattens the first surface Wa or the second surface Wb of the wafer W.

[0033] The grinding device 90 has a rotary table 91. The rotary table 91 is configured to be rotatable about a vertical rotation center line 92 by a rotation mechanism (not shown). Four chucks 93a, 93b that suction-hold the wafer W are provided on the rotary table 91. Porous chucks, for example, are used as the chucks 93a, 93b. The surfaces of the chucks 93a, 93b, i.e., the holding surfaces for the wafer W, have a convex shape in which the central portion protrudes compared to the outer periphery in a side view. Note that although this protrusion in the central portion is minute, in the following description, the protrusion in the central portion of the chucks 93a, 93b may be illustrated exaggerated for clarity.

[0034] Of the four chucks 93a, 93b, two first chucks 93a are chucks used for grinding at a first processing position B1, which will be described later. These two first chucks 93a are arranged in positions that are point-symmetrical with respect to the rotation center line 92. The remaining two second chucks 93b are chucks used for grinding at a second processing position B2, which will be described later. These two second chucks 93b are also arranged in positions that are point-symmetrical with respect to the rotation center line 92. In other words, the first chucks 93a and the second chucks 93b are arranged alternately in the circumferential direction.

[0035] As shown in FIG. 4 , the four chucks 93a, 93b are respectively held by four chuck bases 94. The chuck base 94 is provided with a tilt adjustment mechanism 95 that adjusts the relative tilt between the grinding units 101, 111 (described later) and the chucks 93a, 93b. The tilt adjustment mechanism 95 has a fixed shaft 96 provided on the underside of the chuck base 94 and multiple, for example, two, lift shafts 97. Each lift shaft 97 is configured to be extendable and retractable, and raises and lowers the chuck base 94. The tilt adjustment mechanism 95 tilts the chucks 93a, 93b and the chuck base 94 by vertically raising and lowering the other end of the chuck base 94 using one end of the outer periphery of the chuck base 94 (a position corresponding to the fixed shaft 96) as a base point. This allows the relative tilt between the grinding surfaces of the grinding units 101, 111 at processing positions B1 to B2 (described later) and the upper surfaces of the chucks 93a, 93b to be adjusted. The configuration of the tilt adjustment mechanism 95 is not limited to this, and it is sufficient if it can adjust the relative angle (parallelism) of the surfaces (holding surfaces) of the chucks 93a and 93b with respect to the grinding surfaces of the grinding portions 101 and 111.

[0036] 1, the four chucks 93a, 93b can be moved to delivery positions A1-A2 and processing positions B1-B2 by rotating the rotary table 91. Furthermore, each of the four chucks 93a, 93b is configured to be rotatable about a vertical axis by a rotation mechanism (not shown).

[0037] The first transfer position A1 is a position on the positive X-axis side and the positive Y-axis side of the rotation center line 92 of the turntable 91, where the wafer W is transferred to the first chuck 93a when the first surface Wa is ground. The second transfer position A2 is a position on the positive X-axis side and the negative Y-axis side of the rotation center line 92 of the turntable 91, where the wafer W is transferred to the second chuck 93b when the second surface Wb is ground.

[0038] The first processing position B1 is a position on the negative X-axis side and the negative Y-axis side with respect to the rotation center line 92 of the rotary table 91, and the first grinding unit 100 is disposed therein. As an example, the first grinding unit 100 grinds the first surface Wa or the second surface Wb of the wafer W held by the first chuck 93 a.

[0039] As shown in FIG. 4 , the first grinding unit 100 has a grinding unit 101. The grinding unit 101 has a grinding stone 102, a grinding wheel 103, a mount 104, a spindle 105, and a drive unit 106. The grinding wheel 103 has an annular shape and supports the grinding stone 102 on its underside. The mount 104 supports the grinding wheel 103. The spindle 105 rotates the grinding wheel 103 and the grinding stone 102 via the mount 104. The drive unit 106 is attached to the spindle 105 and incorporates, for example, a motor (not shown), which rotates the spindle 105. As shown in FIG. 1 , the grinding unit 101 is configured to be movable vertically along a support 107 by a drive unit (not shown).

[0040] The second processing position B2 is a position on the negative X-axis side and the positive Y-axis side with respect to the rotation center line 92 of the rotary table 91, and the second grinding unit 110 is disposed therein. The second grinding unit 110 grinds, for example, the second surface Wb or the first surface Wa of the wafer W held by the second chuck 93b.

[0041] The second grinding unit 110 has the same configuration as the first grinding unit 100. That is, as shown in Figures 1 and 4, the second grinding unit 110 has a grinding section 111 (grinding stone 112, grinding wheel 113, mount 114, spindle 115, and drive section 116) and a support column 117.

[0042] As described above, the holding surfaces of the chucks 93a, 93b have a convex shape. Therefore, in the grinding process of the wafer W using the grinding units 100, 110, parts of the annular grinding wheels 102, 112 come into contact with the wafer W as processing points R, as shown by the bold lines in Fig. 5. More specifically, the annularly arranged grinding wheels 102, 112 contact the wafer W in an arc-shaped manner from the center to the outer peripheral edge. In this state, the entire surface of the wafer W is ground by rotating the chucks 93a, 93b and the grinding wheels 103, 113, respectively.

[0043] In addition, in the grinding units 100, 110, the tilt adjustment mechanism 95 described above adjusts the relative angle (tilt) between the holding surfaces of the chucks 93a, 93b and the grinding surfaces of the grinding wheels 102, 112, thereby controlling the shape of the wafer W after grinding to one of flat, convex (convex or A-shaped), concave (concave or V-shaped), W-shaped, and M-shaped, or a combination of any two of these. The flat shape is a shape in which the entire surface of the wafer W is adjusted to a desired flatness (TTV) or less, preferably a shape in which the thickness is controlled to be uniform over the entire surface. The convex shape is a shape in which the thickness at the center of the wafer W is greater than the thickness at the outer periphery. The concave shape is a shape in which the thickness at the central recess of the wafer W is smaller than the thickness at the outer periphery. The W shape is a shape in which the thickness at the center of the radius of the wafer W is smaller than the thickness at the center and outer periphery. The M shape is a shape in which the thickness at the center of the radius of the wafer W is greater than the thickness at the center and outer periphery.

[0044] Further, the first processing position B1 and the second processing position B2 are provided with a grinding water supply unit that supplies grinding water to the grinding surface of the wafer W during the finish grinding process of the wafer W, and a grinding auxiliary water supply unit that supplies grinding auxiliary water. In this embodiment, an outer nozzle 120 provided above the chucks 93 a, 93 b is provided as the grinding auxiliary water supply unit, and an inner nozzle 130 provided below the grinding wheels 103, 113 is provided as the grinding water supply unit.

[0045] 6, the outer nozzle 120 is provided above the chucks 93a and 93b, and is configured to be able to supply auxiliary grinding water from an auxiliary grinding water supply source 121 to the grinding surface of the wafer W at the radially outer side of the grinding wheels 102 and 112. The outer nozzle 120 is also configured to be able to arbitrarily set the supply position of the auxiliary grinding water relative to the grinding surface of the wafer W in the radial direction of the wafer W by operating a supply position adjustment mechanism 122. As an example, Ｅ A first position P1 is closer to the center W than the first position P1. Ｃand a second position P2 close to the side of the outer nozzle 120. The configuration of the supply position adjustment mechanism 122 is not particularly limited, and may be configured to adjust the relative position of the outer nozzle 120 with respect to the grinding surface of the wafer W, for example, by scanning the outer nozzle 120 above the wafer W. Also, for example, the outer nozzle 120 may be configured to be adjustable in tilt angle with respect to the grinding surface of the wafer W, so that the supply direction of the grinding auxiliary water can be set. In one embodiment, the outer nozzle 120 is configured to be able to set the amount of grinding auxiliary water to be supplied to the grinding surface of the wafer W by the flow rate adjustment mechanism 123. The grinding auxiliary water supplied to the grinding surface of the wafer W cools the wafer W by heat exchange with the wafer W, while circulating in the center W. Ｃ From the side to the outer periphery W Ｅ flows to the side.

[0046] As shown in FIG. 6 , the inner nozzle 130 is provided below the grinding wheels 103 and 113 and is configured to supply grinding water from a grinding water supply source 131 to the grinding surface of the wafer W radially inside the grinding wheels 102 and 112. The inner nozzle 130 is configured so that the supply position of the grinding water relative to the grinding surface of the wafer W can be arbitrarily set by operating a supply position adjustment mechanism 132. The configuration of the supply position adjustment mechanism 132 is not particularly limited, and may be configured, for example, so that the supply position of the grinding water can be set by moving the inner nozzle 130. Alternatively, for example, the tilt angle of the inner nozzle 130 relative to the horizontal direction may be adjustable, so that the supply direction of the grinding water can be set. Preferably, the inner nozzle 130 is configured so that the amount of grinding water supplied to the grinding surface of the wafer W can be set by a flow rate adjustment mechanism 133. The inner nozzle 130 may be fixed so as to supply grinding water to a predetermined position on the grinding surface of the wafer W. However, in order to supply the grinding water and grinding auxiliary water to any position on the grinding surface, it is desirable that the inner nozzle 130 be configured to be movable in any direction by the operation of the supply position adjustment mechanism 132. From the viewpoint of appropriately removing grinding debris, frictional heat, and the like generated during grinding of the wafer W, it is particularly desirable that the inner nozzle 130 be configured to be movable at least along the processing point R shown in FIG.

[0047] A thickness measuring device for measuring the thickness of the wafer W after grinding may be provided at the transfer positions A1, A2 or the processing positions B1, B2. In one embodiment, the thickness measuring device is configured to measure the thickness of the wafer W in the circumferential direction at a desired radial position of the wafer W while rotating the wafer W. In this case, the measuring unit of the thickness measuring device is configured to be movable corresponding to the desired radial position at which the thickness is to be measured. The radial position of the wafer W measured by the thickness measuring device includes, for example, a position near the center of the wafer W, near the outer periphery, or near the middle between the center and the outer periphery.

[0048] In one embodiment, the grinding apparatus 90 is provided with a display panel 140. The display panel 140 is, for example, a monitor or a touch panel, and may be attached directly to the grinding apparatus 90 or may be a panel that can be viewed remotely. The display panel 140 displays a screen for operating each process performed in the wafer processing system 1. A signal representing the operation result on the display panel 140 is output to the control device 150, which will be described later.

[0049] As shown in FIG. 7, a display panel 140 serving as an information display unit displays a first input area 141, a second input area 142, a third input area 143, a fourth input area 144, and an instruction area 145 on the same screen.

[0050] In the first input area 141, information on the position and flow rate of auxiliary grinding water is input as control data for the grinding process in the grinding apparatus 90. In the second input area 142, information on whether or not to supply auxiliary grinding water in different steps (steps 1 to 3) of the grinding process is input based on the information on the position and flow rate of auxiliary grinding water input in the first input area 141. In the third input area 143, information for setting and correcting the grinding shape of another wafer W to be processed after a certain wafer W using the same chucks 93 a, 93 b and the same grinding unit in the grinding apparatus 90 is input. In the fourth input area 144, to assist input into the third input area 143, any of the basic shapes of correction patterns 1 and 2, namely, flat, convex, concave, W-shaped, and M-shaped, is displayed, and input into the third input area 143 by selecting one of these. In the instruction area 145, a parameter update section 145 a and an end section 145 b are provided. The parameter update unit 145a confirms the input information in response to the operator's selection. The termination unit 145b terminates the setting of the grinding shape and the correction operation on the display panel 140 in response to the operator's selection.

[0051] In one embodiment, the different steps of the grinding process are not limited to the illustrated steps 1 to 3, but may include other steps as well. The different steps of the grinding process may include, for example, a step of lowering the grinding wheels 102, 112 relative to the wafer W until they come into contact with the wafer W, multiple steps of lowering the grinding wheels 102, 112 to a target position while changing the speed after they come into contact with the wafer W, a step of raising the grinding wheels 102, 112 from the target position to a position where they do not come into contact with the wafer W, and a step of raising the grinding wheels 102, 112 to a retracted position.

[0052] In one embodiment, the first input area 141, the second input area 142, the third input area 143, the fourth input area 144, and the instruction area 145 are not displayed on the same screen, but on different screens that can be switched using selection tabs not shown.

[0053] The wafer processing system 1 described above is provided with at least one control device 150 as a control unit, as shown in FIG. 1 . The control device 150 processes computer-executable instructions that cause the wafer processing system 1 to perform the various processes described herein. The control device 150 may be configured to control each element of the wafer processing system 1 to perform the various processes described herein. In one embodiment, some or all of the control device 150 may be included in the wafer processing system 1. The control device 150 may include a processing unit, a storage unit, and a communication interface. The control device 150 is realized, for example, by a computer. The processing unit may be configured to read from the storage unit a program that provides logic or routines that enable various control operations to be performed, and to execute the read program to perform various control operations. This program may be stored in the storage unit in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit and read from the storage unit by the processing unit for execution. The medium may be various computer-readable storage media H or a communication line connected to the communication interface. The storage medium H may be temporary or non-temporary. The processing unit may be a CPU (Central Processing Unit) or one or more circuits. The storage unit may include a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface may communicate with the wafer processing system 1 via a communication line such as a LAN (Local Area Network).

[0054] Next, a description will be given of a wafer processing method performed using the wafer processing system 1 configured as described above. In this embodiment, a wafer W cut from an ingot using a wire saw or the like, or a lapped wafer W, is subjected to processing to obtain a desired thickness profile of the wafer W.

[0055] First, before processing the wafer W in the wafer processing system 1, the control device 150 determines a target thickness distribution (thickness profile) in the radial direction (within the wafer surface) when grinding the first surface Wa of the wafer W, which will be described later. Hereinafter, such a target thickness distribution during grinding will be referred to as the "grinding target shape." The control device 150 also determines a target thickness distribution in the radial direction when grinding the second surface Wb of the wafer W, which will be described later (St1 in FIG. 8). Note that the method of determining the grinding target shape of the first surface Wa and the grinding target shape of the second surface Wb in the control device 150 will be described later.

[0056] Next, wafer processing is performed in the wafer processing system 1. In this wafer processing, first, a cassette C storing a plurality of wafers W is placed on the cassette mounting table 10 of the carry-in / out station 2. 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 20 removes the wafers W from the cassette C and transfers them to the transition device 30. The wafers W transferred to the transition device 30 are then transferred to the buffer device 72 by the wafer transfer device 60.

[0057] Next, the wafer W is transferred by the wafer transfer device 80 to the grinding device 90 and transferred to the first chuck 93a at the first transfer position A1. The second surface Wb of the wafer W is held by suction on the first chuck 93a.

[0058] Next, the turntable 91 is rotated to move the wafer W to the first processing position B1. Then, the first surface Wa is ground by the first grinding unit 100 based on the grinding target shape of the first surface Wa determined in St1 (St2 in FIG. 8).

[0059] In St2, grinding auxiliary water is supplied to the first surface Wa of the wafer W based on the radial position and flow rate of the grinding auxiliary water supplied from the outer nozzle 120, which are predetermined according to the target grinding shape as described below.

[0060] Here, the radial position of the grinding auxiliary water in St2 and the technical significance of the flow rate will be explained. Fig. 9 is a cross-sectional view showing an example of the shape of the wafer W after grinding when the grinding auxiliary water supply position is the first position P1 in Fig. 6. Fig. 10 is a cross-sectional view showing an example of the shape of the wafer W after grinding when the grinding auxiliary water supply position is the second position P2 in Fig. 6.

[0061] When auxiliary water is supplied during grinding, the supply position of auxiliary water is the outer periphery W Ｅ When the auxiliary water supply position is closer to the center W than when it is closer to the side, Ｃ When the wafer W is closer to the outer periphery W, Ｅ The surrounding area (hereinafter referred to as the "periphery area R Ｅ Furthermore, at the same radial position, the amount of grinding of the outer peripheral region R of the wafer W increases when the flow rate of the grinding auxiliary water is small compared to when the flow rate is large. Ｅ The amount of grinding in the peripheral region R Ｅ is the outer periphery W Ｅ From the center W Ｃ , and extends to a desired radial length.

[0062] That is, when the target shape of grinding is a flat type, as shown in Fig. 9, if the supply position of the grinding auxiliary water is the first position P1 in Fig. 6, the wafer W will be closer to the flat type. On the other hand, as shown in Fig. 10, if the supply position of the grinding auxiliary water is the second position P2 in Fig. 6, the outer peripheral region R Ｅ This is thought to be due to the following reason. That is, as described above, the grinding auxiliary water cools the wafer W while flowing from the supply position toward the outer periphery. At this time, when the grinding auxiliary water is supplied to the second position P2, the amount of grinding in the outer periphery region R becomes larger than when the grinding auxiliary water is supplied to the first position P1. Ｅ As a result, the cooling amount of the outer peripheral region R Ｅ The amount of expansion of the outer peripheral region R is larger. ＥFor the same reason, when the flow rate of the grinding auxiliary water is changed between the first flow rate and the second flow rate that is smaller than the first flow rate, the grinding amount can be changed. That is, when the grinding auxiliary water is supplied at the first flow rate at a certain radial position, the grinding amount in the outer peripheral region R Ｅ When the auxiliary grinding water is supplied to the position at a second flow rate that is smaller than the first flow rate, the amount of grinding in the outer peripheral region R Ｅ The amount of grinding will be larger.

[0063] The radial position and flow rate of the grinding auxiliary water and the outer peripheral region R Ｅ The relationship between the amount of grinding and the amount of grinding may be obtained in advance by experiment or simulation and output to the control device 150. Note that if the flow rate of the grinding auxiliary water is greater than a certain level, changing the flow rate may not change the amount of cooling or expansion, and the amount of grinding may not change. The range of the flow rate of the grinding auxiliary water that can change the amount of grinding may be obtained in advance by experiment or simulation and output to the control device 150.

[0064] Next, the rotary table 91 is rotated to move the wafer W to the first delivery position A1.

[0065] Next, the wafer W is transferred to the cleaning device 70 by the wafer transfer device 80. In the cleaning device 70, the first surface Wa of the wafer W is cleaned (St3 in FIG. 8). In St3, the second surface Wb of the wafer W may also be cleaned.

[0066] Next, the wafer W is transferred to the reversing device 73 by the wafer transfer device 80. In the reversing device 73, the first surface Wa and the second surface Wb of the wafer W are reversed upside down (St4 in FIG. 8). That is, the wafer W is reversed so that the first surface Wa faces downward and the second surface Wb faces upward.

[0067] Next, the wafer W is transferred to the grinding device 90 by the wafer transfer device 80 and transferred to the second chuck 93b at the second transfer position A2. The first surface Wa of the wafer W is held by suction on the second chuck 93b.

[0068] Next, the turntable 91 is rotated to move the wafer W to the second processing position B2. Then, the second surface Wb of the wafer W is ground by the second grinding unit 110 based on the target grinding thickness distribution of the second surface Wb determined in St1 (St5 in FIG. 8).

[0069] Next, the rotary table 91 is rotated to move the wafer W to the second delivery position A2.

[0070] Next, the wafer W is transferred by the wafer transfer device 80 to the cleaning device 70. In the cleaning device 70, the second surface Wb of the wafer W is cleaned (St6 in FIG. 8). In St6, the first surface Wa of the wafer W may also be cleaned.

[0071] Next, the wafer W is transferred to the thickness measuring device 71 by the wafer transfer device 80 or the wafer transfer device 60. The thickness measuring device 71 measures the thickness of the wafer W at multiple points after the second surface Wb has been ground to obtain the thickness distribution of the wafer W, and further calculates the flatness of the wafer W (St7 in FIG. 8). The calculated thickness distribution and flatness of the wafer W are output to, for example, the control device 150.

[0072] In one embodiment, the thickness of the wafer W during or after grinding is measured by a thickness measuring device provided in the grinding device 90. As an example, during grinding, i.e., while the grinding wheel is in contact with the wafer W and grinding is in progress, Ｃ and outer periphery W Ｅ The thickness of the wafer W is measured in the circumferential direction at a position near the middle between the center W and the center W, and the progress of grinding is obtained in real time. Ｃ Near the outer periphery W Ｅ Nearby and central W Ｃ and outer periphery W Ｅ The thickness of the wafer W is measured at a position near the midpoint between the wafer W and the grinding position, thereby obtaining the overall thickness distribution of the wafer W. In one embodiment, the thickness of the wafer W measured by the thickness measuring device during or after grinding is output to, for example, the control device 150. In one embodiment, based on the thickness distribution of the wafer W output to the control device 150, grinding of the wafer W to be processed next in the grinding device 90 is optimized.

[0073] The control device 150 determines optimal etching conditions for the second surface Wb, which optimize the etching amount distribution (etching profile) in the etching process of the second surface Wb, from the thickness distribution and flatness of the wafer W calculated in St7 and output to the control device 150 (St8 in FIG. 8 ). Note that the etching amount is the amount of the wafer W removed by etching, and the etching amount distribution is the distribution of the etching amount in the radial direction (within the wafer surface) of the wafer W. The method for determining the optimal etching conditions for the second surface Wb in the control device 150 will be described later.

[0074] Next, the wafer W is transferred by the wafer transfer device 60 to the etching device 40. In the etching device 40, the second surface Wb of the wafer W is etched with the etching solution E under the optimal etching conditions determined in St8 (St9 in FIG. 8). In St9, the second surface Wb is etched under the optimal etching conditions, thereby processing the second surface Wb into a target shape.

[0075] Next, the wafer W is transferred to the reversing device 51 by the wafer transfer device 60. In the reversing device 51, the first surface Wa and the second surface Wb of the wafer W are reversed upside down (St10 in FIG. 8). That is, the wafer W is reversed so that the first surface Wa faces upward and the second surface Wb faces downward.

[0076] Next, the wafer W is transferred by the wafer transfer device 60 to the thickness measurement device 50. The thickness measurement device 50 measures the thickness of the wafer W at multiple points after etching the second surface Wb to obtain the thickness distribution of the wafer W, and further calculates the flatness of the wafer W (St11 in FIG. 8 ). The calculated thickness distribution and flatness of the wafer W are output to, for example, the control device 150.

[0077] The control device 150 determines optimal etching conditions for the first surface Wa, which optimize the etching amount distribution in the etching process on the first surface Wa, from the thickness distribution and flatness of the wafer W calculated in St11 and output to the control device 150 (St12 in FIG. 8 ). The method for determining the optimal etching conditions for the first surface Wa in the control device 150 will be described later.

[0078] Next, the wafer W is transferred by the wafer transfer device 60 to the etching device 40. In the etching device 40, the first surface Wa of the wafer W is etched with the etching solution E under the optimal etching conditions determined in St12 (St13 in FIG. 8 ). In St13, by etching the first surface Wa under the optimal etching conditions, the etching amount distribution is optimized and the first surface Wa is processed into a target shape.

[0079] Next, the wafer W is transferred by the wafer transfer device 60 to the thickness measurement device 50. The thickness measurement device 50 measures the thickness of the wafer W after etching at multiple points on both the first surface Wa and the second surface Wb, thereby obtaining a thickness distribution of the wafer W (St14 in FIG. 8 ). The thickness measurement device 50 may also calculate the flatness of the wafer W. The obtained thickness distribution of the wafer W is output to, for example, the control device 150, and is used, for example, in processing another wafer W to be processed next in the wafer processing system 1.

[0080] Thereafter, the wafer W that has been subjected to all the processes is transferred to the cassette C on the cassette mounting table 10 via the transition device 30. In this way, a series of wafer processes in the wafer processing system 1 is completed.

[0081] In the above embodiment, the first surface Wa is ground in St 2 and then the second surface Wb is ground in St 5, but the order of grinding these surfaces may be reversed. Also, the second surface Wb is etched in St 9 and then the first surface Wa is etched in St 13, but the order of etching these surfaces may be reversed.

[0082] Furthermore, in the above embodiment, etching of the second surface Wb in St9 was performed under the optimal etching conditions determined in St8, but instead, etching may be performed under predetermined default etching conditions. In such a case, Sts7 and St8 of this embodiment are omitted. Similarly, etching of the first surface Wa in St13 was performed under the optimal etching conditions determined in St12, but instead, etching may be performed under predetermined default etching conditions. In such a case, Sts11 and St12 of this embodiment are omitted.

[0083] Next, the method for determining the above-mentioned optimal etching conditions (Steps 8 and 12 in FIG. 8) will be described. In the following description, the method for determining the optimal etching conditions for the first surface Wa in Step 12 will be described, but the method for determining the optimal etching conditions for the second surface Wb in Step 8 is similar.

[0084] First, before processing the wafer W in the wafer processing system 1, a plurality of learning data are acquired (St100 in FIG. 11 ). The learning data is an etching amount distribution of the wafer W under certain etching conditions. The plurality of learning data is used to determine optimal etching conditions, as will be described later, and is also used to determine a target grinding thickness distribution, as will be described later.

[0085] In St100, etching is performed on a dummy wafer under, for example, a plurality of different etching conditions. Specifically, the dummy wafer is etched by changing, for example, the rotation speed R (also referred to as the number of rotations) of the dummy wafer during etching, the scanning speed V (also referred to as the swing speed) of the nozzle 43, the scanning width L (see the scanning width L in FIG. 3 , also referred to as the swing radius) of the nozzle 43, or the number of loops N of the nozzle 43. In this case, the etching processing time for each dummy wafer is the same. Similar to the etching in St13, the dummy wafer is etched by rotating the dummy wafer and supplying etching solution E from the nozzle 43 to the dummy wafer while the nozzle 43 is reciprocating. In the following description, the reciprocating movement of the nozzle 43 between both ends of the dummy wafer is considered to be one loop.

[0086] Etching of the dummy wafer under each etching condition is carried out for a predetermined desired time (desired number of loops). Then, the etching amount distribution of the dummy wafer is acquired and output to the control device 150. Furthermore, the control device 150 compresses the output etching amount distribution under each etching condition into an etching amount distribution per unit time (unit number of loops), and stores each compressed etching amount distribution as the learning data.

[0087] Although the above description has been given taking the example of acquiring the learning data by etching a dummy wafer as an example, the etching target when acquiring the learning data is not limited to a dummy wafer. Specifically, for example, the etching process results of a product wafer W processed in the wafer processing system 1 may be stored as the learning data. Furthermore, for example, if a film is formed on the first surface Wa of the wafer W, the etching target may be the film, and the etching process results of the film may be stored as the learning data.

[0088] Furthermore, although the learning data is acquired in the wafer processing system 1, it may be acquired outside the wafer processing system 1. In such a case, the control device 150 determines the optimal etching conditions based on the plurality of learning data acquired outside the wafer processing system 1.

[0089] Next, a target etching amount distribution for the etching process in St13 is obtained based on the thickness distribution in the target shape of the wafer W after etching (hereinafter referred to as the "final target shape") and the thickness distribution in the surface shape of the wafer W after grinding obtained in St11 (hereinafter referred to as the "measured shape") (St110 in FIG. 11). The target etching amount distribution for the etching process can be obtained, for example, by calculating the difference between the thickness distribution in the target shape of the wafer W and the thickness distribution in the measured shape.

[0090] Next, multiple pieces of learning data (etching amount distributions) are superimposed, and an optimization method is used to optimize the learning data used for superimposition and the number of times the learning data is superimposed (St111 in FIG. 11 ) so that the target etching amount distribution obtained in St110 is obtained.

[0091] In St111, for example, the control of the etching amount distribution is applied to a knapsack problem to optimize the number of times that the learning data overlaps with the learning data. For example, the etching amount distribution is the knapsack in the knapsack problem, and the learning data are the items in the knapsack problem. Then, the number of times that the learning data overlaps with the learning data is optimized so that the difference between the overlapped etching amount distribution and the target etching amount distribution in St110 is minimized. In other words, the etching amount distribution during etching of the first surface Wa in St13 is optimized.

[0092] Next, the etching conditions corresponding to the learning data optimized in St111 are integrated to determine the optimal etching conditions (St112 in FIG. 11 ). Specifically, the optimal etching conditions are determined by integrating the selected etching conditions so that the optimal number of overlaps is used. In other words, the optimal etching conditions that optimize the etching amount distribution are determined.

[0093] As described above, the optimal etching conditions for the first surface Wa are determined in St 12. In this case, by etching the first surface Wa of the wafer W under the optimal etching conditions in St 13, the etching amount distribution can be optimized and the first surface Wa can be processed into the target shape.

[0094] The optimal etching conditions for the first surface Wa determined in St12 are stored in the control device 150, and a history of the etching conditions is maintained in the control device 150. At this time, the learning data used to determine the optimal etching conditions is also stored. Similarly, the optimal etching conditions (and learning data) for the second surface Wb determined in St8 are also stored in the control device 150, and a history of the etching conditions is maintained in the control device 150. Furthermore, these optimal etching conditions for the surfaces Wa and Wb may be displayed on an etching condition history screen (not shown) on the display panel 140.

[0095] As described above, the etching of the second surface Wb in St9 and the etching of the first surface Wa in St13 may be performed under predetermined etching conditions rather than the optimal etching conditions. For this reason, when setting the etching conditions, the user may be allowed to select whether or not to use the learning data.

[0096] In the above embodiment, the etching amount distribution is used as learning data for controlling the etching process of the wafer W, but the etching amount deviation distribution may also be used. The etching amount deviation distribution is a distribution of values ​​obtained by subtracting the average value of the etching amount from the etching amount within the wafer surface. In such a case, when determining the optimal etching conditions in St8 and St12, the etching amount deviation distribution is used instead of the etching amount distribution. Furthermore, the etching amount deviation distribution is also used when determining the grinding target shape in St1.

[0097] Next, the above-mentioned method for determining the grinding target shape (Step 1 in FIG. 8) will be described. In the following explanation, the method for determining the grinding target shape of the first surface Wa will be described, but the method for determining the grinding target shape of the second surface Wb is also similar.

[0098] In St1, it is first determined whether the surface of the wafer W having a first target shape, which has been determined to be a desired shape in advance, can be etched to form a final target shape (St201 in FIG. 12). The first target shape can be, for example, a flat shape, a convex shape, a concave shape, a W-shape, an M-shape, or a combination of any two of these shapes (hereinafter referred to as a "basic shape"). Details of the determination in St1 will be described later.

[0099] In St201, if it is determined that the surface of the wafer W having the first target shape will be etched to the final target shape ("YES" in FIG. 12), the first target shape is determined as the grinding target shape (St202 in FIG. 12). Then, the process ends. After St1 ends, the process proceeds to St2.

[0100] If it is determined in St201 that the surface of the wafer W having the first target shape will not be etched to the final target shape ("NO" in FIG. 12), the process proceeds to St203.

[0101] In St203, the first target shape is corrected to determine the second target shape. In one embodiment, the correction of the first target shape is performed by correcting the outer peripheral region R Ｅ In this case, the amount of grinding of the outer peripheral region R Ｅ The grinding amount is determined by the radial position and flow rate of the grinding auxiliary water obtained in advance and the peripheral region R Ｅ The grinding amount can be adjusted by changing the radial position and flow rate of the grinding auxiliary water based on the relationship between the grinding amount of the first target shape and the grinding amount of the second target shape. Ｅ The radial position and flow rate of the grinding auxiliary water corresponding to the amount of grinding is output to the control device 150. Then, the process returns to St201, and it is determined whether the surface of the wafer W having the second target shape will become the final target shape by etching.

[0102] Similarly, it is determined whether the surface of the wafer W having the nth target shape (n is a natural number) can be etched to the final target shape (Step 201 in FIG. 12 ). If it is determined that the surface of the wafer W having the nth target shape can be etched to the final target shape, the nth target shape is determined as the grinding target shape (Step 202 in FIG. 12 ). If it is determined that the surface of the wafer W having the nth target shape cannot be etched to the final target shape, the nth target shape is corrected, and the (n+1)th target shape is determined (Step 203 in FIG. 12 ), and the process returns to Step 201.

[0103] In one embodiment, the correction of the nth target shape in St202 includes changing the basic shape used as the nth target shape. Ｅ This includes both changing the amount of grinding.

[0104] After St1 is executed, in St2 and St5, the basic shape and the outer peripheral region R stored in St203 are determined based on the grinding target shape determined in St1.Ｅ and the radial position and flow rate of the grinding auxiliary water corresponding to the grinding amount, and grinding of the wafer W is performed using the above. As a result, the surface of the wafer W after grinding can be etched to a grinding target shape that will become the final target shape.

[0105] Next, a detailed description will be given of how to determine whether the surface of the wafer W having the first target shape will be etched to the final target shape in St201.

[0106] In determining whether the surface of the wafer W having the first grinding target shape can be etched to the final target shape, the optimal etching conditions are first obtained in the same manner as in the method for determining the optimal etching conditions described above (St12 in FIG. 8). Specifically, the target etching amount distribution in the etching process of St13 is obtained based on the first target shape determined in St201 and the final target shape (St210 in FIG. 13).

[0107] Next, multiple pieces of training data (etching amount distributions) are superimposed, and the training data used for superimposition and the number of times the training data is superimposed are optimized using an optimization method to achieve the target etching amount distribution (St211 in FIG. 13). At this time, the training data and the number of times the training data is superimposed are optimized so that the difference between the superimposed etching amount distribution and the target etching amount distribution is minimized. St211 can be performed, for example, by solving a knapsack problem, similar to St111 described above. Furthermore, optimal etching conditions are determined based on the superimposed etching amount distributions. Determining optimal etching conditions based on the superimposed etching amount distributions can be performed in the same manner as St112.

[0108] Next, the minimum difference between the superimposed etching amount distribution optimized in St211 and the target etching amount distribution is compared with a desired threshold, and it is determined whether the difference is equal to or smaller than the threshold (St212 in FIG. 13).

[0109] In St212, if the difference is equal to or less than the threshold, it is determined that the surface of the wafer W having the grinding target shape will become at least sufficiently close to the final target shape by etching using the optimal etching conditions. That is, if the difference is determined to be equal to or less than the threshold in St212, it is determined in St201 of FIG. 12 that the surface of the wafer W having the grinding target shape will become the final target shape by etching.

[0110] In St212, if the difference exceeds the threshold, it is determined that the surface of the wafer W having the grinding target shape will not be etched to the final target shape even if the optimal etching conditions are used. In other words, if the difference exceeds the threshold in St212, it is determined in St201 of FIG. 12 that the surface of the wafer W having the grinding target shape will not be etched to the final target shape.

[0111] 12 , if it is determined that the surface of the wafer W having the grinding target shape will be etched to the final target shape, the optimal etching conditions determined in St211 are output to the control device 150. Thereafter, the etching of the second surface Wb in St9 may be performed under the optimal etching conditions determined in St211. In such a case, Sts7 and St8 of this embodiment may be omitted. Similarly, the etching of the first surface Wa in St13 may be performed under the optimal etching conditions determined in St211. In such a case, Sts11 and St12 of this embodiment may be omitted.

[0112] As an example of the flow of St201, consider a case where the first target shape is a flat type shown by the solid line in Fig. 14(a) and the final target shape is a sine curve type (wave type) shown by the dotted lines in Fig. 14(a) and (b). In this case, if the minimum difference between the superimposed etching amount distribution optimized in St211 and the target etching amount distribution exceeds a desired threshold, it is determined that the post-etching shape (solid line in Fig. 14(b)) does not match the final target shape, as shown in Fig. 14(b).

[0113] At this time, the first target shape is corrected so that the basic shape shown by the solid line in FIG. 15A is a flat type with an outer peripheral region R Ｅ In this case, the minimum difference of St211 becomes equal to or smaller than the desired threshold value, and it is determined that the shape after etching shown by the solid line in FIG. 15B becomes the final target shape shown by the dotted line in FIG. 15B.

[0114] According to the wafer processing method of the above embodiment, it is possible to determine in advance whether a combination of a grinding target shape and a final target shape is such that the etched wafer W cannot be made into the final target shape by conventional grinding and etching techniques even if the above-described optimization of the etching amount distribution is performed. Furthermore, when it is determined that the surface of the wafer W will not be made into the final target shape by etching, correction of the grinding target shape can be performed to make the surface of the wafer W after grinding into a grinding target shape that will be the final target shape by etching.

[0115] From another perspective, the wafer processing method according to the above embodiment allows a shape of the wafer W that could not be obtained by conventional grinding and etching techniques even when the etching amount distribution is optimized to be set as the final target shape. That is, such a final target shape can be a flat shape that is flat in the radial direction of the wafer W, or any of a convex shape (convex in the middle, A-shaped), a concave shape (concave in the middle, V-shaped), an M-shaped, a W-shaped, a sine curve shape (wave shape), or a combination of any two of these shapes, or any other desired shape.

[0116] In the above embodiment, the basic shape is used as the first target shape, but the present invention is not limited to this. Ｅ In this case, for example, the processing result of the wafer W processed previously may be used to determine the grinding amount of the basic shape of the first target shape of the current wafer W and the grinding amount of the outer peripheral region R Ｅ The grinding amount may be determined.

[0117] Example 1 Hereinafter, Example 1 using the wafer processing method according to the above embodiment will be described. Fig. 16 is an explanatory diagram showing the final target shape of the wafer W and the actual shape after etching in the wafer processing method according to Example 1. In Fig. 16, the horizontal axis indicates the radial position of the wafer W, and the vertical axis indicates the relative thickness. Fig. 17 is an explanatory diagram showing the shape of the wafer W after grinding in the wafer processing method according to Example 1.

[0118] In Example 1, first, the final target shape was determined to be a convex (A-shaped) shape, as shown by the dotted line in FIG. 16 . Furthermore, the first target shape as the grinding target shape of the first surface Wa was determined to be a convex shape. Next, it was determined whether the surface of the wafer W having the first target shape would become the final target shape by etching (see St201 in FIG. 12 and St210 to St212 in FIG. 13 ). As a result, it was determined that the surface of the wafer W having the first target shape would become the final target shape by etching. Therefore, the first target shape was determined as the grinding target shape of the first surface Wa (see St1 in FIG. 8 ). Further, the grinding target shape of the second surface Wb was determined in a similar manner. Then, St2 to St14 were sequentially performed. As a result, a convex shape was obtained after grinding as shown in FIG. 17 , and a wafer W having an appropriate convex thickness distribution as shown by the solid line in FIG. 16 was obtained after etching.

[0119] Example 2 Hereinafter, Example 2 using the wafer processing method according to the above embodiment will be described. Fig. 18 is an explanatory diagram showing the final target shape of the wafer W and the actual shape after etching in the wafer processing method according to Example 2. In Fig. 18, the horizontal axis indicates the radial position of the wafer W, and the vertical axis indicates the relative thickness. Fig. 19 is an explanatory diagram showing the shape of the wafer W after grinding in the wafer processing method according to Example 2.

[0120] In Example 2, first, the final target shape was determined to be a sine curve shape (hereinafter referred to as "wave shape") as shown by the dotted line in FIG. 18 . Furthermore, the first target shape as the grinding target shape of the first surface Wa was determined to be flat. Next, it was determined whether the surface of the wafer W having the first target shape would become the final target shape by etching (see St201 in FIG. 12 and St210 to St212 in FIG. 13 ). As a result, it was determined that the surface of the wafer W having the first target shape would not become the final target shape by etching. Specifically, the minimum difference between the superimposed etching amount distribution optimized in St211 and the target etching amount distribution exceeded the desired threshold (see St212). Therefore, the first target shape was corrected to determine the second target shape (see St203). In Example 2, the correction of the first target shape was performed by adjusting the outer peripheral region R Ｅ That is, the basic shape was a flat type, and the grinding amount of the outer peripheral region R Ｅ The second target shape was determined so as to increase the amount of grinding of the outer peripheral region R. Ｅ The radial position and flow rate of the grinding auxiliary water corresponding to the amount of grinding of the wafer W were output. Next, it was determined whether the surface of the wafer W having the second target shape would become the final target shape by etching (see St201 in FIG. 12 and St210 to St212 in FIG. 13). As a result, it was determined that the surface of the wafer W having the second target shape would become the final target shape by etching. Therefore, the second target shape was determined as the grinding target shape of the first surface Wa (see St1 in FIG. 8). Similarly, the grinding target shape of the second surface Wb was determined. Thereafter, St2 to St14 were executed sequentially. At this time, grinding was performed in St2 and St5 using the basic shape and the radial position and flow rate of the grinding auxiliary water output as described above. As a result, after grinding, as shown in FIG. 19, the outer peripheral region R was larger than the flat type. Ｅ After etching, the wafer W had a suitable wavy thickness distribution as shown by the solid line in FIG.

[0121] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the components of the above-described embodiments may be arbitrarily combined. Such an arbitrary combination naturally provides the functions and effects of each of the components involved in the combination, and also provides other functions and effects that are apparent to those skilled in the art from the description of this specification.

[0122] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that would be apparent to a person skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0123] 1 wafer processing system 40 etching device 90 grinding device 150 control device W wafer

Claims

1. A substrate processing method for processing a substrate, comprising: grinding a surface of the substrate to a target grinding shape; determining a target etching amount distribution based on the target grinding shape and a predetermined final target shape; etching the ground surface of the substrate based on the target etching amount distribution; and determining whether the surface of the substrate having the target grinding shape will become the final target shape by etching.

2. The substrate processing method of claim 1, further comprising: correcting the grinding target shape when it is determined in the determining that the surface of the substrate having the grinding target shape will not become the final target shape by etching; and determining whether the surface of the substrate having the corrected grinding target shape will become the final target shape by etching.

3. The substrate processing method according to claim 2, wherein the grinding target shape is determined in advance to include adjusting the amount of grinding in the outer peripheral region of the substrate.

4. The substrate processing method according to claim 2, wherein correcting the grinding target shape includes adjusting the amount of grinding in the outer peripheral region of the substrate.

5. The substrate processing method of claim 4, wherein the grinding step includes supplying auxiliary grinding water to the surface of the substrate, and wherein, in adjusting the amount of grinding in the outer peripheral region of the substrate, determining a supply position of the auxiliary grinding water or a flow rate of the auxiliary grinding water corresponding to the amount of grinding, and in grinding, supplying the auxiliary grinding water to the surface of the substrate using the determined supply position of the auxiliary grinding water or the determined flow rate of the auxiliary grinding water.

6. The substrate processing method according to claim 5, further comprising inputting and displaying information relating to the correction of the grinding target shape on an information display unit, wherein the information includes a supply position of the grinding auxiliary water or a flow rate of the grinding auxiliary water.

7. A substrate processing method according to any one of claims 1 to 6, comprising: superimposing a plurality of learning data containing information on etching amount distribution, and optimizing the learning data used for the superimposition and the number of times the learning data is superimposed so that the difference between the superimposed etching amount distribution and the target etching amount distribution is minimized; comparing the difference between the superimposed etching amount distribution and the target etching amount distribution with a threshold, wherein if the difference is equal to or less than the threshold, it is determined that the surface of the substrate having the grinding target shape will become the final target shape by the etching; and if the difference is greater than the threshold, it is determined that the surface of the substrate having the grinding target shape will not become the final target shape by the etching.

8. A substrate processing apparatus for processing a substrate, comprising: a grinding unit that grinds a surface of the substrate; an etching unit that etches the ground surface of the substrate; and a control unit, wherein the control unit executes control including: grinding the surface of the substrate to a grinding target shape; determining a target etching amount distribution based on the grinding target shape and a predetermined final target shape; etching the ground surface of the substrate based on the target etching amount distribution; and determining whether the surface of the substrate having the grinding target shape will become the final target shape by the etching.

9. The substrate processing apparatus of claim 8, wherein the control unit performs control including: correcting the grinding target shape when it is determined in the determining that the surface of the substrate having the grinding target shape will not become the final target shape by etching; and determining whether the surface of the substrate having the corrected grinding target shape will become the final target shape by etching.

10. The substrate processing apparatus according to claim 9, wherein the grinding target shape is determined in advance to include adjusting the amount of grinding in an outer peripheral region of the substrate.

11. The substrate processing apparatus according to claim 9, wherein correcting the grinding target shape includes adjusting the amount of grinding in an outer peripheral region of the substrate.

12. A substrate processing apparatus as described in claim 11, wherein the grinding unit includes a grinding auxiliary water supply unit that supplies grinding auxiliary water to the surface of the substrate, and the grinding step includes supplying grinding auxiliary water to the surface of the substrate, and the control unit performs control including, in adjusting the grinding amount in the outer peripheral region of the substrate, determining a supply position of the grinding auxiliary water or a flow rate of the grinding auxiliary water corresponding to the grinding amount, and in grinding, supplying the grinding auxiliary water to the surface of the substrate using the determined supply position of the grinding auxiliary water or the determined flow rate of the grinding auxiliary water.

13. The substrate processing apparatus according to claim 12, further comprising an information display unit for inputting and displaying information relating to the correction of the grinding target shape, said information including a supply position of said grinding auxiliary water or a flow rate of said grinding auxiliary water.

14. The substrate processing apparatus of any one of claims 8 to 13, wherein the determining step includes: acquiring a target etching amount distribution based on the grinding target shape and the final target shape; overlaying a plurality of learning data containing information on the etching amount distribution, and optimizing the number of times the learning data and the learning data used for the overlay are overlaid so that the difference between the overlaid etching amount distribution and the target etching amount distribution is minimized; and comparing the difference between the overlaid etching amount distribution and the target etching amount distribution with a threshold value, wherein if the difference is equal to or less than the threshold value, it is determined that the surface of the substrate having the grinding target shape will become the final target shape by etching, and if the difference is greater than the threshold value, it is determined that the surface of the substrate having the grinding target shape will not become the final target shape by etching.

15. A readable computer storage medium storing a program that runs on a computer of a control unit that controls a substrate processing apparatus to cause the substrate processing apparatus to execute a substrate processing method for processing a substrate, wherein the substrate processing apparatus comprises: a grinding unit that grinds the surface of the substrate; an etching unit that etches the ground surface of the substrate; and the control unit, and the substrate processing method includes: grinding the surface of the substrate to a grinding target shape; determining a target etching amount distribution based on the grinding target shape and a predetermined final target shape; etching the ground surface of the substrate based on the target etching amount distribution; and determining whether the surface of the substrate having the grinding target shape will become the final target shape by the etching.

Images