Substrate Processing Method and Substrate Processing System

Abstract

Determining an optimal etching condition comprises: acquiring training data including an etching amount distribution in a diameter direction of an object to be etched when the surface of the object to be etched is etched in a plurality of different etching conditions; and determining the optimal etching condition by using the Covariance Matrix Adaptation Evolution Strategy so that the etching amount distribution predicted by using the training data from the following equations (1)-(6) is close to a target etching amount distribution. (1): ERscan(R)=Σ{LPk×ERref(R)×Ratioscan(R)} (2): Ratioscan(R)=b0×exp(b1×T+b2)+C (3): b0=f(Sk,Vk) (4): b1=f(Sk,Vk) (5): b2=f(Sk,Vk) (6): T=(Lk-R) / Vk

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a substrate processing method including a grinding step of grinding the surface of a substrate, a measuring step of measuring the thickness of the ground substrate, a condition determining step of determining the processing conditions of a wet etching process performed on the substrate based on the measured thickness of the substrate, and a step of supplying a processing liquid to the ground substrate and performing a wet etching process based on the determined processing conditions.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technology according to the present disclosure appropriately controls the surface shape of an object to be etched after the etching process.

Means for Solving the Problems

[0005] One aspect of the present disclosure is a substrate processing method for processing a substrate, comprising: determining optimal etching conditions; rotating an etching target on the substrate based on the optimal etching conditions; and supplying an etching solution from an etching solution supply unit to a surface of the etching target while moving an etching solution supply unit back and forth radially above a rotation center of the etching target, thereby etching the surface; wherein determining the optimal etching conditions includes acquiring learning data including a radial etching amount distribution of the etching target when the surface of the etching target is etched under a plurality of different etching conditions; and determining the optimal etching conditions using a covariance matrix adaptive evolution strategy such that an etching amount distribution predicted from the following equations (1) to (6) using the learning data approximates a target etching amount distribution. ER scan (R)=Σ{LP k ×ER ref (R)×Ratio scan (R)} ···(1) Ratio scan (R)=b0×exp(b1×T+b2)+C (2) b0=f(S k ,V k ) ···(3) b1=f(S k ,V k ) ···(4) b2=f(S k ,V k ) ···(5) T=(L k -R) / V k ···(6) however, Σ: k=1~N integration, N: Number of overlaps (an integer greater than or equal to 2) ER scan : The amount of etching when the etching liquid supply unit is moved back and forth, ER ref : the amount of etching when the etching liquid supply unit is not reciprocated, Ratio scan : scan ratio, LPk : The number of loops (k = 1 to N) when one reciprocating movement of the etching liquid supply part between both ends of the object to be etched is regarded as one loop, R: The position from the center of the object to be etched, T: The non-discharge time when the etching liquid is not supplied, C: Constant, S k : The rotation speed (k = 1 to N) when rotating the object to be etched, V k : The scan speed (k = 1 to N) when reciprocatingly moving the etching liquid supply part, L k : The scan width (k = 1 to N) when reciprocatingly moving the etching liquid supply part.

Advantages of the Invention

[0006] According to the present disclosure, the surface shape of the object to be etched after the etching process can be appropriately controlled.

Brief Description of the Drawings

[0007]

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DETAILED DESCRIPTION OF THE INVENTION

[0008] In the manufacturing process of semiconductor devices, a semiconductor substrate (hereinafter referred to as "wafer") on which a plurality of devices such as electronic circuits are formed on the surface is ground and thinned, and further, the ground surface of the wafer is smoothed. The smoothing of the ground surface is performed by so-called spin etching, for example, by supplying an etching solution from above the ground surface of the wafer while rotating the wafer.

[0009] Patent Document 1 described above discloses that a wet etching process is performed on the ground wafer to remove the damage layer formed on the surface of the wafer by the grinding process. In the condition determination step described in Patent Document 1, based on the thickness of the wafer obtained in the measurement step, as conditions for the wet etching process, the operation of the nozzle for supplying the processing solution, the rotation speed of the wafer, the supply amount of the processing solution, the supply time of the processing solution, the type of the processing solution, etc. are determined.

[0010] However, when spin etching is performed by supplying the processing solution while rotating the wafer as in the method disclosed in Patent Document 1, it is difficult to perform precise etching control because the processing solution supplied to the wafer surface flows radially outward due to centrifugal force. More specifically, it has been difficult to appropriately control the surface shape of the wafer after the etching process, particularly at the center of the wafer.

[0011] Therefore, it has been proposed to rotate the wafer and supply an etching solution from a nozzle to the surface of the wafer while reciprocating (scanning) the nozzle in the radial direction passing through the center of the wafer to etch the surface. Hereinafter, such etching may be referred to as "scan etching". In scan etching, while supplying the etching solution to the central portion of the wafer, a flow of the etching solution is generated on the surface of the wafer at the central portion to control the surface shape of the wafer.

[0012] Here, in order to control the surface shape of the wafer after the etching process, it is essential to appropriately control the etching amount distribution (etching profile) in the wafer radial direction. The control of the etching amount distribution is performed by adjusting etching conditions (etching recipe) such as the rotation speed (number of revolutions) of the wafer, the scan speed and scan width in the reciprocating movement of the nozzle so as to obtain a target etching amount distribution.

[0013] However, conventionally, the control of the etching amount distribution is mainly performed by a so-called trial and error method in which an engineer predicts the variation of the etching amount distribution, sequentially acquires data regarding the etching amount distribution, and matches it to the target etching amount distribution. In such a case, the control of the etching amount distribution depends on the ability of the engineer, and individual differences may occur in the working time required for the control and the degree of completion of the control.

[0014] The technology according to the present disclosure appropriately controls the surface shape of the object to be etched after the etching process. Hereinafter, a wafer processing system as a substrate processing system according to the present embodiment and a wafer processing method as a substrate processing method will be described with reference to the drawings. In the present specification and the drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0015] In the wafer processing system 1 described below according to this embodiment, as shown in FIG. 1, processing is performed on a polymer wafer T as a substrate in which a first wafer W and a second wafer S are joined. Hereinafter, in the first wafer W, the surface on the side joined to the second wafer S is referred to as a front surface Wa, and the surface on the side opposite to the front surface Wa is referred to as a back surface Wb. Similarly, in the second wafer S, the surface on the side joined to the first wafer W is referred to as a front surface Sa, and the surface on the side opposite to the front surface Sa is referred to as a back surface Sb.

[0016] The first wafer W is a semiconductor wafer such as a silicon substrate, for example, and a device layer Dw including a plurality of devices is formed on the front surface Wa side. Further, a bonding film Fw is formed on the device layer Dw, and the first wafer W is bonded to the second wafer S via the bonding film Fw. As the bonding film Fw, for example, an oxide film (THOX film, SiO2 film, TEOS film), SiC film, SiCN film, or an adhesive is used.

[0017] The second wafer S has, for example, the same configuration as the first wafer W, and a device layer Ds and a bonding film Fs are formed on the front surface Sa. Note that the second wafer S does not necessarily have to be a device wafer on which the device layer Ds is formed, and may be, for example, a support wafer that supports the first wafer W. In such a case, the second wafer S functions as a protective material that protects the device layer Dw of the first wafer W.

[0018] As shown in FIG. 2, 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 polymer wafers T is loaded / unloaded to / from the outside. The processing station 3 includes various processing apparatuses that perform desired processing on the polymer wafer T.

[0019] The loading / unloading station 2 is provided with a cassette mounting table 10 for mounting a plurality of, for example, three cassettes C. Further, on the negative X-axis side of the cassette mounting table 10, a wafer transfer device 20 is provided adjacent to 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. Further, the wafer transfer device 20 has, for example, two transfer arms 22, 22 that hold and transfer the polymerized wafer T. Each transfer arm 22 is configured to be movable in the horizontal direction, the vertical direction, around the horizontal axis, and around the vertical axis. Note that the configuration of the transfer arm 22 is not limited to this embodiment and can take any configuration. And the wafer transfer device 20 is configured to be able to transfer the polymerized wafer T to the cassette C of the cassette mounting table 10 and a transition device 30 described later.

[0020] On the negative X-axis side of the wafer transfer device 20 in the loading / unloading station 2, a transition device 30 for transferring the polymerized wafer T to and from the processing station 3 is provided adjacent to the wafer transfer device 20.

[0021] The processing station 3 is provided with, for example, three processing blocks B1 to B3. The first processing block B1, the second processing block B2, and the third processing block B3 are arranged side by side in this order from the positive X-axis side (the loading / unloading station 2 side) to the negative direction side.

[0022] The first processing block B1 is provided with an etching device 40, a thickness measurement device 41, and a wafer transfer device 50. The etching device 40 and the thickness measurement device 41 are arranged in a stacked manner. Note that the number and arrangement of the etching device 40 and the thickness measurement device 41 are not limited to this.

[0023] The etching device 40 etches the back surface Wb (grinding surface) of the first wafer W after grinding in the processing device 80 described later, further thins the first wafer W (polymerized wafer T) after grinding, and smooths the grinding surface by removing the grinding marks generated by the grinding process. Note that the detailed configuration of the etching device 40 will be described later.

[0024] In one example, the thickness measurement device 41 includes a measurement unit (not shown) and a calculation unit (not shown). The measurement unit includes a sensor that measures the thickness of the first wafer W after etching at a plurality of points. The calculation unit acquires the thickness distribution of the first wafer W from the measurement results (the thickness of the first wafer W) obtained by the measurement unit, and further calculates the flatness (TTV: Total Thickness Variation) of the first wafer W. Note that the calculation of the thickness distribution and flatness of the first wafer W may be performed by a control device 90 described later instead of the calculation unit. In other words, a calculation unit (not shown) may be provided in the control device 90 described later. Note that the configuration of the thickness measurement device 41 is not limited to this and can be arbitrarily configured.

[0025] The wafer transfer device 50 is disposed on the negative X-axis side of the transition device 30. The wafer transfer device 50 has, for example, two transfer arms 51, 51 that hold and transfer the polymerized wafer T. Each transfer arm 51 is configured to be movable in the horizontal direction, the vertical direction, around the horizontal axis, and around the vertical axis. The wafer transfer device 50 is configured to be able to transfer the polymerized wafer T to the transition device 30, the etching device 40, the thickness measurement device 41, a cleaning device 60 described later, a thickness measurement device 61 described later, and a buffer device 62 described later.

[0026] The second processing block B2 is provided with a cleaning device 60, a thickness measurement device 61, a buffer device 62, and a wafer transfer device 70. The cleaning device 60, the thickness measurement device 61, and the buffer device 62 are arranged in a stacked manner. Note that the number and arrangement of the cleaning device 60, the thickness measurement device 61, and the buffer device 62 are not limited to this.

[0027] The cleaning device 60 cleans the back surface Wb (grinding surface) of the first wafer W after grinding in a processing device 80 described later. For example, a brush is brought into contact with the back surface Wb to scrub and clean the back surface Wb. Note that a pressurized cleaning liquid may be used for cleaning the first wafer W. Further, the cleaning device 60 may be configured to be able to simultaneously clean the back surface Sb of the second wafer S when cleaning the first wafer W.

[0028] In one example, the thickness measurement device 61 includes a measurement unit (not shown) and a calculation unit (not shown). The measurement unit includes a sensor that measures the thickness of the first wafer W after grinding at a plurality of points. The calculation unit obtains the thickness distribution of the first wafer W from the measurement results (thickness of the first wafer W) by the measurement unit, and further calculates the flatness (TTV) of the first wafer W. Note that the calculation of the thickness distribution and flatness of the first wafer W may be performed by the control device 90 described later instead of the calculation unit. In other words, a calculation unit (not shown) may be provided in the control device 90 described later. Note that the configuration of the thickness measurement device 61 is not limited to this and can be arbitrarily configured.

[0029] The buffer device 62 temporarily holds the pre-process polymerization wafer T transferred from the first processing block B1 to the second processing block B2. The configuration of the buffer device 62 is arbitrary. Note that the buffer device 62 may have an alignment mechanism (not shown) that adjusts the center position of the polymerization wafer T with respect to the chuck 83 described later and / or the horizontal direction orientation of the polymerization wafer T.

[0030] The wafer transfer device 70 is disposed, for example, on the positive Y-axis side of the cleaning device 60, the thickness measurement device 61, and the buffer device 62. The wafer transfer device 70 has, for example, two transfer arms 71, 71 that adsorb and hold the polymerization wafer T by an adsorption holding surface (not shown) and transfer it. Each transfer arm 71 is supported by an articulated arm member 72 and is configured to be movable in the horizontal direction, vertical direction, around the horizontal axis, and around the vertical axis. And the wafer transfer device 70 is configured to be able to transfer the polymerization wafer T to the etching device 40, the thickness measurement device 41, the cleaning device 60, the thickness measurement device 61, the buffer device 62, and the processing device 80 described later.

[0031] The third processing block B3 is provided with a processing device 80. The processing device 80 grinds and thins the first wafer W and functions as a thinning device in the present disclosure.

[0032] The processing device 80 has a rotary table 81. The rotary table 81 is configured to be rotatable about a vertical rotation center line 82 by a rotation mechanism (not shown). On the rotary table 81, two chucks 83 for adsorbing and holding the polymerized wafer T are provided. The chucks 83 are evenly arranged on the same circumference as the rotary table 81. The two chucks 83 can be moved to the delivery position A0 and the processing position A1 when the rotary table 81 rotates. Further, each of the two chucks 83 is configured to be rotatable about a vertical axis by a rotation mechanism (not shown).

[0033] At the delivery position A0, the polymerized wafer T is delivered. At the processing position A1, a grinding unit 84 is arranged, and the first wafer W is ground while the second wafer S is adsorbed and held by the chuck 83. The grinding unit 84 has a grinding portion 85 provided with a grinding wheel (not shown) that is annular and rotatable. Further, the grinding portion 85 is configured to be movable in the vertical direction along a support column 86.

[0034] Note that the configuration of the processing device 80 is not limited to this. For example, four chucks 83 may be provided on the rotary table 81, and the four chucks 83 may be configured to be movable among a delivery position of the polymerized wafer T, a rough grinding portion (not shown) for performing rough grinding of the first wafer W, a semi-finishing grinding portion (not shown) for performing semi-finishing grinding of the first wafer W, and a finish grinding portion (not shown) for performing finish grinding of the first wafer W. Further, for example, the processing device 80 may be provided with a thickness measuring device (not shown) for measuring the thickness of the first wafer W after grinding at a plurality of points.

[0035] The above wafer processing system 1 is provided with a control device 90. The control device 90 is a computer including, for example, 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 the polymerized wafer T in the wafer processing system 1. Note that the above program may be recorded on a computer-readable storage medium H and installed from the storage medium H into the control device 90. Further, the storage medium H may be temporary or non-temporary.

[0036] Next, the configuration of the above-described etching device 40 will be described. As shown in FIG. 3, the etching device 40 includes a wafer holding unit 100 as a substrate holding unit, a rotation mechanism 101, and an etching solution supply unit 102.

[0037] The wafer holding unit 100 holds the outer edge portion of the polymerized wafer T at a plurality of points, three points in this embodiment. Note that the configuration of the wafer holding unit 100 is not limited to the illustrated example. For example, the wafer holding unit 100 may include a chuck that adsorbs and holds the polymerized wafer T from below. The rotation mechanism 101 rotates the polymerized wafer T (first wafer W) held by the wafer holding unit 100 about a vertical rotation center line 100a.

[0038] The etching solution supply unit 102 has, as an example, a nozzle that supplies the etching solution E to the back surface Wb of the first wafer W held by the wafer holding unit 100. The etching solution supply unit 102 is provided above the wafer holding unit 100 and is configured to be movable in the horizontal and vertical directions by a movement mechanism 103. In one example, the etching solution supply unit 102 is configured to be reciprocally movable (scan movable) through the rotation center line 100a of the wafer holding unit 100, that is, above the center portion of the first wafer W as shown in FIG. 4. In the following description, one reciprocation of the etching solution supply unit 102 is defined as one loop.

[0039] Etching solution E contains at least hydrofluoric acid, nitric acid, or a mixed acid in order to appropriately etch the silicon of the first wafer W that can be an etching target. Further, phosphoric acid or sulfuric acid may be contained in the etching solution E. Note that the etching target is not limited to the first wafer W, and may be, for example, amorphous silicon. Also, the etching target of the present embodiment is not limited to the back surface Wb of the first wafer W. For example, it can also be applied to the case of processing a wafer on which processing by the processing apparatus 80 is not performed. For example, when a film is formed on the back surface Wb, the film also becomes an etching target.

[0040] In the above etching apparatus 40, while rotating the first wafer W and reciprocating the etching solution supply unit 102, scan etching is performed in which the etching solution is supplied from the etching solution supply unit 102 to the back surface Wb of the first wafer W. In the present embodiment, a prediction model is used to predict the etching amount distribution in scan etching.

[0041] The prediction model of the etching amount distribution is for the case of performing scan etching under the etching conditions of a constant scan speed and symmetric scan as shown in FIG. 5. That is, the scan speed V when reciprocating the etching solution supply unit 102 is constant. Also, the scan width L of the etching solution supply unit 102 is symmetric with respect to the center of the first wafer W, and the etching solution supply unit 102 reciprocates between the scan one end “+L” and the scan other end “−L”. Hereinafter, this scan etching sequence may be referred to as a “constant speed scan sequence”, and the derived prediction model may be referred to as a “constant speed scan model”.

[0042] The constant speed scan model consists of the following formulas (1') to (6'). ER scan (R)=ER ref (R)×Ratio scan (R) ···(1') Ratio scan (R)=b0×exp(b1×T+b2)+C ···(2') b0 = f(S, V) ···(3’) b1 = f(S, V) ···(4’) b2 = f(S, V) ···(5’) T = (L - R) / V ···(6’) However, ER scan : Etching amount when the etching liquid supply unit 102 is reciprocated, ER ref : Etching amount when the etching liquid supply unit 102 is not reciprocated, Ratio scan : Scan ratio, R: Position from the center of the first wafer W, T: Non-discharge time when the etching liquid E is not supplied, C: Constant, S: Rotation speed when rotating the first wafer W, V: Scan speed when reciprocating the etching liquid supply unit 102, L: Scan width when reciprocating the etching liquid supply unit 102.

[0043] The functions in each of the above formulas (3’) to (5’) are determined by analyzing learning data. For example, etching is performed on a dummy wafer under a constant speed scan sequence under a plurality of different etching conditions to obtain learning data regarding the etching amount distribution. Specifically, the rotation speed S of the dummy wafer, the scan speed V when reciprocating the etching liquid supply unit 102, and the scan width L of the etching liquid supply unit 102 are changed to perform etching on the dummy wafer. At this time, the processing time for etching each dummy wafer is the same.

[0044] Etching of the dummy wafer under each etching condition is performed for a predetermined desired time. Then, the etching amount distribution of the dummy wafer is obtained and output to the control device 90. Further, in the control device 90, the etching amount distribution under each output etching condition is compressed into an etching amount distribution (etching rate) per unit time or per unit loop, and each of the compressed etching amount distributions is stored as learning data.

[0045] Figure 6 shows an example of the acquired learning data. The rotation speed S of the dummy wafer was changed to S1 to S5. The scan speed V of the etching liquid supply unit 102 was changed to V1 to V3. The scan width L of the etching liquid supply unit 102 was changed to L1 to L4. Thus, the etching amount distribution was acquired for a plurality of, in this example, 60 types of etching conditions. In the graph of each learning data, the horizontal axis indicates the radial position from the center of the dummy wafer (0 (zero) on the horizontal axis) to one outer end, and the vertical axis indicates the etching amount (etching rate).

[0046] In the above, the case of acquiring the above learning data by etching a dummy wafer has been described as an example, but the etching target when acquiring learning data is not limited to a dummy wafer. Specifically, for example, the etching process result of the first wafer W actually processed in the wafer processing system 1 may be stored as the above learning data. Further, for example, when a film is formed on the back surface Wb of the first wafer W, the etching target may be the film, and the etching process result of the film may be stored as the above learning data.

[0047] Next, a detailed derivation method of the above-described constant speed scan model will be described.

[0048] First, the present inventors grasped the etching amount distribution in scan etching. Then, it was found that the etching amount distribution when the etching liquid supply unit 102 is fixed and does not reciprocate (hereinafter, sometimes referred to as "no scan") becomes the reference etching amount distribution of the etching amount distribution predicted by the constant speed scan model.

[0049] FIG. 7 shows the etching amount distribution when the rotation speed S is S5, the scan speed V is V3, and the scan width L is changed from L1 to L4 among the learning data shown in FIG. 6 above. FIG. 7 also shows the reference etching amount distribution in the case of no scan. Referring to FIG. 7, in scan etching, only the etching amount distribution on the inner peripheral side fluctuates starting from the scan width L, and the etching amount distribution on the outer peripheral side does not fluctuate. In other words, in scan etching, only the etching amount distribution on the inner peripheral side of the scan width L fluctuates from the reference etching amount distribution without scan, and the etching amount distribution on the outer peripheral side of the scan width L shows the same behavior as the reference etching amount distribution. Therefore, the etching amount distribution without scan can be used as a reference.

[0050] Next, the inventors of the present invention separated the variation in the etching amount distribution in scan etching. Specifically, based on the concept that there is a reference etching amount distribution without scan, the ratio of the etching amount distribution of scan etching to the reference etching amount distribution is defined as the scan ratio Ratio scan by the following formula (7). With this scan ratio Ratio scan , the effect of scan etching can be quantitatively separated. FIG. 8 shows the scan ratio Ratio scan when the rotation speed S is S5, the scan speed V is changed from V1 to V3, and the scan width L is changed from L1 to L4. The horizontal axis in FIG. 8 indicates the radial position from the center (0 (zero) on the horizontal axis) of the first wafer W to one outer end, and the vertical axis indicates the scan ratio Ratio scan . Referring to FIG. 8, Starting from the scan width L the scan ratio Ratio scan on the inner peripheral side fluctuates, and the variation in the etching amount distribution in the above scan etching can be quantitatively separated and grasped. Then, from the following formula (7), the following formula (1') in the constant-speed scan model is derived. Ratio scan (R)=ER scan (R) / ER ref (R) ···(7) ER scan (R)=ER ref (R)×Ratioscan (R) ···(1’) However, Ratio scan : Scan ratio, ER scan : Etching amount when the etching liquid supply unit 102 is reciprocally moved, ER ref : Etching amount when the etching liquid supply unit 102 is not reciprocally moved.

[0051] Also, the non-discharge time T was defined by the following formula (6’). The non-discharge time T is the time during which the etching liquid E is not supplied to the inner peripheral side due to the movement of the etching liquid supply unit 102. And during this non-discharge time T, the etching amount decreases. FIG. 9 shows the non-discharge time T when the rotation speed S is S5, the scan speed V is changed from V1 to V3, and the scan width L is changed from L1 to L4. The horizontal axis of FIG. 9 indicates the radial position from the center (0 (zero) on the horizontal axis) of the first wafer W to one outer end, and the vertical axis indicates the non-discharge time T. Referring to FIG. 9, Starting from the scan width L it is possible to capture the variation of the non-discharge time T on the inner peripheral side. T = (L - R) / V ···(6’) However, T: Non-discharge time during which the etching liquid E is not supplied, V: Scan speed when the etching liquid supply unit 102 is reciprocally moved, L: Scan width when the etching liquid supply unit 102 is reciprocally moved.

[0052] Next, the inventors examined the relationship between the scan ratio Ratio scan and the non-discharge time T. FIG. 10 shows the relationship between the scan ratio Ratio scan and the non-discharge time T when the rotation speed S is S5 and the scan speed V is changed from V1 to V3. The horizontal axis of FIG. 10 indicates the non-discharge time T, and the vertical axis indicates the scan ratio Ratio scan . Referring to FIG. 10, with respect to the non-discharge time T, the scan ratio Ratio scanIt exponentially decreases and can be defined by the decay curve model of the following formula (2’). This decay curve model is also suitable for explaining the behavior of the actual physical phenomenon that the etching amount decreases as the time when the etching solution E is not supplied becomes longer. Ratio scan (R)=b0×exp(b1×T+b2)+C ···(2’) However, b0: Scale (intercept), b1: Decay rate (slope), b2: Decay delay value, C: Asymptote.

[0053] The above b0 is the scale (intercept) of the decay curve, and b1 is the decay rate (slope) of the decay curve. b2 is the decay delay value of the decay curve. For example, b2 is a correction term used when the amount of the etching solution E is large and the remaining solution on the first wafer W is large, and the influence such as the decay not occurring immediately is large. C is the asymptote of the decay curve. For example, when C is absent, the scan ratio Ratio scan mathematically approaches 0 (zero). However, in reality, once the etching solution E is supplied, the first wafer W is always etched, so the scan ratio Ratio scan does not become 0 (zero). C is a correction term for correcting this phenomenon. Also, C can be determined, for example, by the method of setting C = 0 if C < 0 and leaving C as it is if C > 0 after once analyzing with the above formula (2’).

[0054] Note that when b2 and C are judged to be practically unnecessary, it is possible to omit them by setting b2 = 0 and C = 0.

[0055] Also, the scale b0, the decay rate b1, and the decay delay value b2 depend on the rotation speed S and the scan speed V, and can be defined by the following formulas (3’) to (5’), respectively. b0=f(S,V) ···(3’) b1=f(S,V) ···(4’) b2=f(S,V) ···(5’) However, S: Rotation speed when rotating the first wafer W, V: Scan speed when reciprocally moving the etching solution supply unit 102.

[0056] Here, in FIG. 10, the thick line is the measured value obtained by experiment, and the thin line is the calculated value calculated by the above formula (2’) of the constant speed scan model. The measured value and the calculated value are substantially in agreement, and it is confirmed that the attenuation curve model of the above formula (2’) is appropriate.

[0057] From the above, a constant speed scan model consisting of the following formulas (1’) to (6’) is derived. ER scan (R)=ER ref (R)×Ratio scan (R) ···(1’) Ratio scan (R)=b0×exp(b1×T+b2)+C ···(2’) b0=f(S,V) ···(3’) b1=f(S,V) ···(4’) b2=f(S,V) ···(5’) T=(L - R) / V ···(6’)

[0058] FIG. 11 is a graph comparing the measured value of the etching amount distribution obtained by experiment (thick line in FIG. 11) and the calculated value of the etching amount distribution calculated from the constant speed scan model (thin line in FIG. 11). The rotation speed S was changed to S1 to S4, the scan speed V was changed to V1 to V3, and the scan width L was changed to L1 to L4. The measured value and the calculated value are substantially in agreement, and it is confirmed that the constant speed scan model of the above formulas (1’) to (6’) is appropriate.

[0059] In this embodiment, the scan sequence under any etching conditions can be expressed by superimposing a plurality of constant-speed scan sequences. In other words, by superimposing the etching amount distributions calculated by the constant-speed scan model, any etching amount distribution can be controlled. In such a case, the scan etching model for predicting any etching amount distribution is obtained by the following formula (8). The following formula (8) is an example with the number of superposition times being 3. Note that the number of loop times may be time. (Etching amount distribution) =(Number of loop 1)×(Etching amount distribution of constant-speed scan model 1) +(Number of loop 2)×(Etching amount distribution of constant-speed scan model 2) +(Number of loop 3)×(Etching amount distribution of constant-speed scan model 3) ···(8)

[0060] Then, by transforming each of the above formulas (1') to (6') of the constant-speed scan model, the scan etching model can be expressed by the following formulas (1) to (6). At this time, the etching amount distribution calculated by the above formula (1') is converted into the etching amount distribution per loop unit. ER scan (R)=Σ{LP k ×ER ref (R)×Ratio scan (R)} ···(1) Ratio scan (R)=b0×exp(b1×T+b2)+C ···(2) b0=f(S k ,V k ) ···(3) b1=f(S k ,V k ) ···(4) b2=f(S k ,V k ) ···(5) T=(L k -R) / V k ···(6) However, Σ: Integration from k = 1 to N, N: Number of superposition times (an integer of 2 or more), ER scan: Etching amount when the etching liquid supply unit 102 is reciprocated, ER ref : Etching amount when the etching liquid supply unit 102 is not reciprocated, Ratio scan : Scan ratio, LP k : Number of loops (k = 1 to N) when one loop is the reciprocating movement of the etching liquid supply unit between both ends of the first wafer W, R: Position from the center of the first wafer W, T: Non-discharge time when the etching liquid E is not supplied, C: Constant, S k : Rotation speed (k = 1 to N) when rotating the first wafer W, V k : Scan speed (k = 1 to N) when reciprocating the etching liquid supply unit 102, L k : Scan width (k = 1 to N) when reciprocating the etching liquid supply unit 102.

[0061] Next, the wafer processing performed using the wafer processing system 1 configured as described above will be described. In this embodiment, a polymerized wafer T is formed in advance in a bonding device (not shown) outside the wafer processing system 1. Also, a range of 0.5 mm to 3 mm in the radial direction from the outer edge of the first wafer W, for example, may be removed in advance.

[0062] First, a cassette C containing a plurality of polymerized wafers T is placed on the cassette mounting table 10 of the loading / unloading station 2. Next, the polymerized wafer T in the cassette C is taken out by the wafer transfer device 20 and transferred to the transition device 30. The polymerized wafer T transferred to the transition device 30 is transferred to the buffer device 62 by the wafer transfer device 50. Note that in the buffer device 62, the center position of the polymerized wafer T with respect to the chuck 83 and / or the horizontal direction of the polymerized wafer T may be adjusted.

[0063] Next, the polymerized wafer T is transported to the processing device 80 by the wafer transfer device 70 and delivered to the chuck 83 at the delivery position A0. At the chuck 83, the back surface Sb of the second wafer S is adsorbed and held. Next, the chuck 83 is moved to the processing position A1, and the back surface Wb of the first wafer W is ground by the grinding unit 84. By such grinding treatment, the thickness of the first wafer W (polymerized wafer T) is reduced to a desired grinding target thickness (step S1 in FIG. 12).

[0064] Next, the polymerized wafer T is transported to the thickness measuring device 61 by the wafer transfer device 70. At the thickness measuring device 61, the thickness distribution of the first wafer W after grinding is obtained by measuring the thickness of the first wafer W (polymerized wafer T) after grinding at a plurality of points, and further the flatness of the first wafer W is calculated (step S2 in FIG. 12). The calculated thickness distribution and flatness of the first wafer W are output to, for example, the control device 90. In addition, when a thickness measuring device is provided in the processing device 80, the thickness of the first wafer W after grinding may be measured by the thickness measuring device of the processing device 80.

[0065] The control device 90 determines the optimum etching conditions in the subsequent etching process from the output thickness distribution and flatness of the first wafer W (step S3 in FIG. 12). The detailed method for determining the optimum etching conditions in the control device 90 will be described later.

[0066] The polymerized wafer T whose thickness of the first wafer W has been measured is then transported to the cleaning device 60 by the wafer transfer device 70 or the wafer transfer device 50. At the cleaning device 60, the back surface Wb, which is the ground surface of the first wafer W after grinding, is cleaned (step S4 in FIG. 12). Also, at the cleaning device 60, the back surface Sb of the second wafer S may be cleaned as described above. In addition, when the thickness after grinding is measured by the thickness measuring device 61 as in the present embodiment, the order of step S2 and step S3 and step S4 may be reversed. That is, after cleaning the back surface Wb of the first wafer W at the cleaning device 60, the thickness of the first wafer W at the thickness measuring device 61 may be measured, and the optimum etching conditions in the etching process may be determined.

[0067] Next, the polymerized wafer T is transported to the etching apparatus 40 by the wafer transfer apparatus 50. In the etching apparatus 40, under the optimal etching conditions, the back surface Wb, which is the ground surface of the first wafer W, is etched by the etching liquid E (step S5 in FIG. 12).

[0068] When etching the first wafer W, first, the wafer holding portion 100 (the first wafer W) is rotated about the vertical rotation center line 100a, and the supply (discharge) of the etching liquid E from the etching liquid supply portion 102 is started to start etching the back surface Wb.

[0069] Furthermore, when etching the first wafer W, while continuing the supply of the etching liquid E from the etching liquid supply portion 102, as shown in FIG. 4, the etching liquid supply portion 102 is reciprocally moved (scanned) with the rotation center line 100a as the midpoint above the rotation center of the first wafer W, that is, so as to pass through the rotation center line 100a. Details of the method for determining etching conditions such as the rotation speed of the first wafer W, the scan speed when reciprocally moving the etching liquid supply portion 102, and the scan width of the etching liquid supply portion 102 will be described later.

[0070] When the desired etching amount is obtained on the first wafer W, the supply of the etching liquid E from the etching liquid supply portion 102 is stopped, the back surface Wb of the first wafer W is rinsed with pure water, and then spin-dried. Thereafter, the rotation of the wafer holding portion 100 (the first wafer W) is stopped, and the etching of the first wafer W is completed.

[0071] Here, the optimal etching conditions for the first wafer W are determined based on the thickness distribution and flatness of the first wafer W after grinding as described above. Specifically, the optimal etching conditions are determined based on the difference between the measured values of the thickness distribution and flatness of the first wafer W in the thickness measuring device 61 and the thickness distribution and flatness in the target surface shape of the first wafer W after etching (hereinafter referred to as the "target shape"). Then, in step S5, by etching the first wafer W under the optimal etching conditions, the difference between the measured value and the target value of the thickness of the first wafer W is removed by etching, and the surface of the first wafer W is processed into the target shape. According to this embodiment, the appropriate target surface shape of the first wafer W can be obtained regardless of the surface shape of the first wafer W after grinding.

[0072] Next, the polymerized wafer T is transported to the thickness measuring device 41 by the wafer transport device 50. In the thickness measuring device 41, the thickness distribution of the first wafer W after etching is obtained by measuring the thickness of the first wafer W (polymerized wafer T) after etching at a plurality of points, and further the flatness of the first wafer W is calculated (step S6 in FIG. 12). The calculated thickness distribution and flatness of the first wafer W are output to, for example, the control device 90, and as an example, are used for the processing of other polymerized wafers T to be processed next in the wafer processing system 1. When measuring the thickness of the first wafer W after grinding with the thickness measuring device of the processing device 80, the thickness of the first wafer W after etching may be measured in the thickness measuring device 61.

[0073] Thereafter, the polymerized wafer T that has undergone all the processes is transported to the cassette C on the cassette mounting table 10 via the transition device 30. Thus, a series of wafer processes in the wafer processing system 1 is completed.

[0074] Next, a detailed method for determining the above-described optimal etching conditions (step S3 in FIG. 12) will be described. FIG. 13 is a flowchart showing the main steps of the method for determining the optimal etching conditions, and FIG. 14 is a block diagram showing the method for determining the optimal etching conditions.

[0075] First, when determining the optimal etching conditions, prior to the processing of the polymerization wafer T in the wafer processing system 1, learning data is acquired (step S3-1 in FIG. 13). A prediction model of the etching amount distribution is derived from the learning data (step S3-2 in FIG. 13).

[0076] In step S3-1, as described above, for example, etching is performed on a dummy wafer with a constant-speed scan sequence, and learning data regarding the etching amount distribution shown in FIG. 6 is acquired.

[0077] In step S3-2, as described above, a prediction model of the etching amount distribution, that is, a scan etching model, which consists of the following formulas (1) to (6) is derived. At this time, the functions in each of the following formulas (3) to (5) are determined by analyzing the learning data acquired in step S3-1. ER scan (R)=Σ{LP k ×ER ref (R)×Ratio scan (R)} ···(1) Ratio scan (R)=b0×exp(b1×T+b2)+C ···(2) b0=f(S k ,V k ) ···(3) b1=f(S k ,V k ) ···(4) b2=f(S k ,V k ) ···(5) T=(L k -R) / V k ···(6) However, Σ: Integration from k = 1 to N, N: Number of superposition times (an integer of 2 or more), ER scan : Etching amount when the etching liquid supply unit 102 is reciprocally moved, ER ref : Etching amount when the etching liquid supply unit 102 is not reciprocally moved, Ratioscan : Scan ratio, LP k : The number of loops (k = 1 to N) when the reciprocating movement of the etching solution supply part between both ends of the first wafer W is taken as one loop, R: Position from the center of the first wafer W, T: Non-discharge time when the etching solution E is not supplied, C: Constant, S k : Rotation speed when rotating the first wafer W (k = 1 to N), V k : Scan speed when reciprocating the etching solution supply part 102 (k = 1 to N), L k : Scan width when reciprocating the etching solution supply part 102 (k = 1 to N).

[0078] In parallel with steps S3-1 and S3-2, obtain the target etching amount distribution in the etching process of step S5 above (step S3-3 in FIG. 13). The target etching amount distribution is obtained based on the thickness distribution (hereinafter referred to as "target thickness distribution") in the target shape of the first wafer W after etching and the thickness distribution (hereinafter referred to as "measured thickness distribution") in the surface shape of the first wafer W after grinding obtained in step S2 above. The target etching amount distribution can be obtained, for example, by calculating the difference between the target thickness distribution and the measured thickness distribution of the first wafer W. In this example, the target etching amount distribution is flat within the wafer surface.

[0079] Next, CMA-ES (Covariance Matrix Adaptation Evolution Strategy) is executed so that the etching amount distribution calculated using the scan etching model in step S3-2 approximates the target etching amount distribution obtained in step S3-3 (step S3-4 in FIG. 13). CMA-ES is an evolution strategy (ES) that optimizes based on covariance (CMA). Then, as shown in FIG. 14, the input data is a constant-speed scan model, a target etching amount distribution, and the number of superposition times (number of models). The output data is etching conditions, including the rotation speed S (S1 to S3) of the first wafer W, the scan speed V (V1 to V3) of the etching liquid supply unit 102, the scan width L (L1 to L3) of the etching liquid supply unit 102, and the number of loop times LP (LP1 to LP3).

[0080] When CMA-ES is executed as described above, the etching conditions are optimized so that the etching amount distribution calculated using the scan etching model approximates the target etching amount distribution. This optimized etching condition is determined as the optimal etching condition (step S3-5 in FIG. 13).

[0081] Thereafter, in step S4, after the back surface Wb of the first wafer W is cleaned, in step S5, the back surface Wb of the first wafer W is etched under the optimal etching conditions. That is, in the etching apparatus 40, the polymer wafer T (the first wafer W) is rotated at the rotation speed determined under the optimal etching conditions, and while moving the etching liquid supply unit 102 at the determined scan speed and scan width, the etching liquid E is supplied to the first wafer W.

[0082] The determination of the optimal etching conditions according to this embodiment and the etching process for the first wafer W based on the optimal etching conditions are performed as described above.

[0083] According to the above embodiments, the etching amount distribution can be appropriately predicted using the scan etching model composed of the above formulas (1) to (6). Therefore, when controlling the etching amount distribution, it is possible to suppress the working time required for control and improve the degree of control completion without depending on the ability of engineers as in the prior art. In addition, it is possible to suppress the variation in man-hours when determining the optimal etching conditions in step S3 and improve the accuracy of the optimal etching conditions.

[0084] Also, since the CMA-ES is used to determine the optimal etching conditions in step S3, thereafter, the first wafer W can be etched under the optimal etching conditions in step S5. As a result, the etching amount distribution in the etching process can be made closer to the target etching amount distribution, and as a result, the surface shape of the first wafer W after etching can be made into the target shape. In other words, the optimal etching conditions can be determined from indefinite etching conditions, and the surface shape of the first wafer W after etching can be appropriately controlled.

[0085] When the inventors actually performed simulations, in the case where the target etching amount distribution was any of V-shaped, A-shaped, M-shaped, and W-shaped, the variation in the thickness distribution of the first wafer W after etching could be kept within the allowable range. Also, the flatness (TTV) of the first wafer W after etching was improved compared to the prior art. The V-shaped is a distribution having a substantially V-shaped in a graph with the horizontal axis being the wafer position and the vertical axis being the etching amount, where the etching amount at the center of the first wafer W is smaller than the etching amounts at both ends. The A-shaped is a distribution having a substantially A-shaped in the above graph, where the etching amount at the center of the first wafer W is larger than the etching amounts at both ends and has a shape opposite to the V-shaped. The M-shaped is a distribution having a shape in which two A-shapes are arranged with the center of the first wafer W in between in the above graph and having a substantially M-shaped as a whole. The W-shaped is a distribution having a shape in which two V-shapes are arranged with the center of the first wafer W in between in the above graph and having a substantially W-shaped as a whole.

[0086] In addition, since steps S1 to S6 are performed for each stacked wafer T, even if the surface shapes before etching (after grinding in this embodiment) are different for each wafer, the surface shape of the first wafer W after etching can be controlled for each wafer to the target shape.

[0087] Note that, for example, when the target etching amount distribution is flat, increasing the number of superposition times can make the etching amount distribution calculated by the scan etching model closer to flat. And when the present inventors performed simulations, it was found that when the number of superposition times was set to 2 or more, the residual distribution between the etching amount distribution of the scan etching model and the target etching amount distribution fell within the allowable range.

[0088] In the above embodiment, the case where various processes are performed on the back surface Wb of the first wafer W in the stacked wafer T in which the first wafer W and the second wafer S are bonded has been described as an example, but the processing target is not limited to this. For example, a thinning process or an etching process may be performed on a single wafer. The processing target may be a film formed on the surface of the wafer, such as an oxide film or titanium nitride. In such a case, the etching liquid supply unit 102 in the etching apparatus 40 may be configured to be able to arbitrarily switch the supply of different types of etching liquid E according to the etching target. Further, for example, when a film formed on the wafer surface is the etching target, the etching processing result of the film may be stored as described above. Training data In the thickness measurement device 61, the thickness of the film is measured. Also, when a protective tape is attached to the device surface of the wafer, a thinning process or an etching process may be performed on the surface opposite to the protective tape. Further, a thinning process or an etching process may be performed on a wafer cut out from an ingot by a wire saw or the like and lapped. Regardless of the processing target, the etching process can be performed under the optimum etching conditions of the above embodiment.

[0089] Further, for example, when a film is formed on the back surface Wb of the first wafer, the film may be an etching target. In such a case, for example, the thickness measuring device 61 measures the thickness of the film. In step S2, instead of the thickness of the first wafer W, the thickness of the film is measured, and further, the film thickness distribution and the film flatness are calculated. Then, in step S3, based on the calculated film thickness distribution and flatness, the optimum etching conditions are determined.

[0090] Moreover, although the wafer processing system 1 includes various devices other than the etching device 40, the device configuration to which the present disclosure is applied is not limited thereto. For example, the processing device 80, which is a thinning device, may be omitted. In such a case, the etching target is not limited to the wafer after the thinning process. Further, for example, the technology of the present disclosure can also be applied when etching a wafer in a single etching device.

[0091] In the above embodiment, the first wafer W is thinned by the processing device 80, but the thinning method is not limited thereto. For example, the thinning process of the first wafer W includes polishing the back surface Wb of the first wafer W. Alternatively, for example, the first wafer W may be thinned by separation based on a modified layer (not shown) formed by laser processing inside the first wafer W. In such a case, the wafer processing system 1 is provided with a laser processing device (not shown) for forming the modified layer (not shown) instead of the processing device 80.

[0092] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The above embodiments may be omitted, substituted, or changed in various forms without departing from the scope and gist of the appended claims.

Description of Reference Numerals

[0093] 1 Wafer processing system 40 Etching device 90 Control device 102 Etching solution supply unit E Etching solution T Polymerized wafer W First wafer S second wafer

Claims

1. A substrate processing method for processing a substrate, comprising: determining optimal etching conditions; rotating an etching target on the substrate based on the optimal etching conditions, and supplying an etching liquid from an etching liquid supply unit to the surface of the etching target while reciprocating the etching liquid supply unit in a radial direction through a position above the rotation center of the etching target to etch the surface; Determining the optimal etching conditions includes: acquiring learning data including an etching amount distribution in the radial direction of the etching target when etching the surface of the etching target under a plurality of different etching conditions; determining the optimal etching conditions using a covariance matrix adaptation evolution strategy such that an etching amount distribution predicted from the following formulas (1) to (6) approximates a target etching amount distribution. ER ｓｃａｎ E(R) = Σ{Lp ｋ × E(R ｒｅｆ (R) × Ratio ｓｃａｎ (R)}...(1) Ratio ｓｃａｎ (R) = b ０ × exp(b １ × T + b ２ ) + C... (2) b ０ = f(S ｋ , V ｋ )...(3) b １ = f(S ｋ , V ｋ )...(4) b ２ = f(S ｋ , V ｋ )...(5) T = (L ｋ - R) / V ｋ ... (6) However, Σ: Summation from k = 1 to N, N: Number of superposition times (an integer of 2 or more), ER ｓｃａｎ : Etching amount when the etching solution supply unit is reciprocated, ER ｒｅｆ : Etching amount when the etching solution supply unit is not reciprocated, Ratio ｓｃａｎ : Scan ratio, LP ｋ : The number of loops (k = 1 to N) when taking the reciprocating movement of the etching solution supply unit between both ends of the object to be etched as one loop, R: Position from the center of the etching target, T: Non-discharge time when the etching liquid is not supplied, C: Constant, S ｋ : Rotation speed when rotating the object to be etched (k = 1 to N), V ｋ : The scan speed (k = 1 to N) when reciprocally moving the etching liquid supply unit, L ｋ : Scanning width (k = 1 to N) when reciprocally moving the etching solution supply unit.

2. The substrate processing method according to claim 1, wherein the optimal etching conditions include the number of loop times, the rotation speed, the scan speed, and the scan width.

3. The substrate processing method according to claim 1 or 2, wherein the function in each of the above formulas (3) to (5) is determined based on an analysis of the learning data.

4. Before etching the surface of the etching target, measuring the thickness of the etching target to obtain a thickness distribution in the radial direction of the etching target; predicting the etching amount distribution based on the obtained thickness distribution of the etching target. The substrate processing method according to claim 1 or 2.

5. Before etching the surface of the etching target, measuring the thickness of the etching target to obtain a thickness distribution of the etching target, wherein the target etching amount distribution is obtained based on the obtained thickness distribution of the etching target and a target thickness distribution of the etching target. The substrate processing method according to claim 1 or 2.

6. The substrate processing method according to claim 4, further comprising thinning the substrate before measuring the thickness of the etching target.

7. A substrate processing system for processing a substrate, comprising: An etching apparatus that rotates an object to be etched on the substrate and supplies an etching liquid from the etching liquid supply unit to the surface of the object to be etched while reciprocating the etching liquid supply unit in the radial direction through above the rotation center of the object to be etched to etch the surface. A control device that controls the etching of the surface of the object to be etched in the etching apparatus based on the optimum etching conditions. The control device Acquires learning data including the etching amount distribution in the radial direction of the object to be etched when etching the surface of the object to be etched under a plurality of different etching conditions. A substrate processing system that uses the learning data to determine the optimum etching conditions using a covariance matrix adaptation evolution strategy so that the etching amount distribution predicted from the following formulas (1) to (6) approximates the target etching amount distribution. ER ｓｃａｎ (R) = Σ{LP ｋ × ER ｒｅｆ (R) × Ratio ｓｃａｎ (R)}... (1) Ratio ｓｃａｎ (R) = b ０ × exp(b １ × T + b ２ ) + C... (2) b ０ = f(S ｋ , V ｋ )...(3) b １ = f(S ｋ , V ｋ )...(4) b ２ = f(S ｋ , V ｋ )...(5) T = (L ｋ - R) / V ｋ ・・・(6) However, Σ: Summation for k = 1 to N N: Number of superposition times (an integer of 2 or more) ER ｓｃａｎ : Etching amount when the etching solution supply unit is reciprocated, ER ｒｅｆ : Etching amount when the etching solution supply unit is not reciprocated, Ratio ｓｃａｎ : Scanning ratio, LP ｋ : The number of loops (k = 1 to N) when the reciprocating movement of the etching solution supply unit between both ends of the object to be etched is regarded as one loop, R: Position from the center of the object to be etched T: Non-discharge time when the etching liquid is not supplied C: Constant S ｋ : Rotation speed when rotating the object to be etched (k = 1 to N), V ｋ : The scan speed when reciprocating the etching solution supply unit (k = 1 to N), L ｋ : Scan width (k = 1 to N) when reciprocally moving the etching liquid supply unit.

8. The substrate processing system according to claim 7, wherein the optimum etching conditions include the number of loop times, the rotation speed, the scan speed, and the scan width.

9. The substrate processing system according to claim 7 or 8, wherein the control device determines the functions in each of the above formulas (3) to (5) by analyzing the learning data.

10. Having a thickness measuring device for measuring the thickness of the object to be etched before etching. The substrate processing system according to claim 7 or 8, wherein the control device predicts the etching amount distribution based on the thickness distribution of the object to be etched obtained from the thickness of the object to be etched measured by the thickness measuring device.

11. Having a thickness measuring device for measuring the thickness of the object to be etched before etching. The substrate processing system according to claim 7 or 8, wherein the control device obtains the target etching amount distribution based on the thickness distribution of the object to be etched obtained from the thickness of the object to be etched measured by the thickness measuring device and the target thickness distribution of the object to be etched.

12. Having a thinning device for thinning the substrate. The substrate processing system according to claim 11, wherein the thickness measuring device measures the thickness of the object to be etched on the thinned substrate.

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