Substrate Processing Method and Substrate Processing System

Abstract

The present invention includes: acquiring learning data in which an etching amount distribution in the radial direction of an object to be etched includes an etching amount distribution when the surface of the object to be etched is etched under a plurality of different etching conditions; and predicting an etching amount distribution with respect to etching conditions to be predicted, on the basis of the following formulas (1) to (6) and by using the learning data. (1): ERscan (R) = ERref (R) × Ratioscan (R), (2): Ratioscan (R) = b0 × exp (b1 × T + b2) + C, (3): b0 = f (S, V), (4): b1 = f(S, V), (5): b2 = f(S, V), (6): T = (L - R) / V

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 Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technology according to the present disclosure appropriately predicts the etching amount distribution in the radial direction of an etching target when etching the surface of the etching target while rotating the etching target and reciprocatingly moving an etching liquid supply unit in the radial direction.

Means for Solving the Problems

[0005] One aspect of the present disclosure is a substrate processing method for processing a substrate, including rotating an etching target on the substrate and reciprocatingly moving an etching liquid supply unit in a radial direction through above the rotation center of the etching target while supplying an etching liquid from the etching liquid supply unit to the surface of the etching target to etch the surface, and predicting an etching amount distribution in the radial direction of the etching target when etching the surface of the etching target under predicted etching conditions, wherein the prediction of the etching amount distribution includes obtaining learning data including etching amount distributions when etching the surface of the etching target under a plurality of different etching conditions, and predicting the etching amount distribution under the predicted etching conditions from the following formulas (1) to (6) using the learning data. 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 : The etching amount when the etching liquid supply unit is reciprocatingly moved; ER ref : The etching amount when the etching liquid supply unit is not reciprocatingly moved; Ratio scan : Scan ratio; R: The position from the center of the etching target; T: The non-discharge time when the etching liquid is not supplied; C: Constant; S: The rotation speed when rotating the etching target; V: The scan speed when reciprocatingly moving the etching liquid supply unit; L: The scan width when reciprocatingly moving the etching liquid supply unit.

Advantages of the Invention

[0006] According to the present disclosure, when etching the surface of an object to be etched while rotating the object to be etched and reciprocatingly moving an etching solution supply unit in the radial direction, the etching amount distribution in the radial direction of the object to be etched can be appropriately predicted.

Brief Description of the Drawings

[0007]

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BEST MODE FOR CARRYING OUT THE INVENTION

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

[0009] In the above-described Patent Document 1, it is disclosed that a wet etching process is performed on the ground wafer to remove a 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 performing spin etching in which a processing liquid is supplied while rotating the wafer as in the method disclosed in Patent Document 1, it is difficult to perform precise etching control because the processing liquid 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 supply an etching liquid from a nozzle to the surface of the wafer and etch the surface while rotating the wafer and reciprocatingly moving (scanning) the nozzle in the radial direction passing through the center of the wafer. Hereinafter, such etching may be referred to as "scan etching". In scan etching, the surface shape of the wafer is controlled by supplying the etching liquid to the center of the wafer and generating a flow of the etching liquid on the surface of the wafer at the center.

[0012] Here, in order to control the surface shape of the wafer after the etching process, it is important 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 adjusts 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 predicts the etching amount distribution in the radial direction of an object to be etched in scan etching. Hereinafter, a wafer processing system and a wafer processing method according to the present embodiment will be described with reference to the drawings. In the present specification and 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 according to the present embodiment described later, as shown in FIG. 1, processing is performed on a polymerized wafer T as a substrate in which a first wafer W and a second wafer S are bonded. Hereinafter, in the first wafer W, the surface on the side bonded 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 bonded 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, for example, a semiconductor wafer such as a silicon substrate, 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 second wafer S is bonded 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 the loading / unloading station 2 and the processing station 3 are integrally connected. In the loading / unloading station 2, for example, a cassette C capable of accommodating a plurality of polymerized wafers T is loaded / unloaded to / from the outside. The processing station 3 is equipped with various processing apparatuses for performing desired processing on the polymerized wafers 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. The wafer transfer device 20 has, for example, two transfer arms 22, 22 for holding and transferring the polymerized wafers 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 wafers T to / from the cassette C on the cassette mounting table 10 and a transition device 30 described later.

[0020] In the loading / unloading station 2, on the negative X-axis side of the wafer transfer device 20, a transition device 30 for transferring the polymerized wafers T between 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 measuring device 41, and a wafer transfer device 50. The etching device 40 and the thickness measuring device 41 are arranged in a stacked manner. Note that the number and arrangement of the etching device 40 and the thickness measuring 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 (bonded wafer T) after grinding, and smooths the grinding surface by removing the grinding marks generated by the grinding process. The detailed configuration of the etching device 40 will be described later.

[0024] The thickness measurement device 41 includes a measurement unit (not shown) and a calculation unit (not shown) in one example. 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 (thickness of the first wafer W) by the measurement unit, and further calculates the flatness (TTV: Total Thickness Variation) of the first wafer W. 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. 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 bonded wafer T. Each transfer arm 51 is configured to be movable in the horizontal direction, vertical direction, around the horizontal axis, and around the vertical axis. The wafer transfer device 50 is configured to be able to transfer the bonded wafer T to the transition device 30, the etching device 40, the thickness measurement device 41, the cleaning device 60 described later, the thickness measurement device 61 described later, and the 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. 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 the 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 for cleaning the first wafer W, a pressurized cleaning liquid may be used. 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 such a 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 polymerized 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, the vertical direction, around the horizontal axis, and around the vertical axis. The wafer transfer device 70 is configured to be able to transfer the polymerized 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). Two chucks 83 for adsorbing and holding the polymerized wafer T are provided on the rotary table 81. 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 the 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 section 85 provided with a grinding wheel (not shown) that is annular and rotatable. The grinding section 85 is configured to be movable in the vertical direction along a support column 86.

[0034] Note that the configuration of the processing apparatus 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 between the delivery position of the polymerized wafer T, a rough grinding section (not shown) for performing rough grinding of the first wafer W, a semi-finishing grinding section (not shown) for performing semi-finishing grinding of the first wafer W, and a finish grinding section (not shown) for performing finish grinding of the first wafer W. Further, for example, the processing apparatus 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 section (not shown). A program for controlling the processing of the polymerized wafer T in the wafer processing system 1 is stored in the program storage section. 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 etching apparatus 40 described above will be described. As shown in FIG. 3, the etching apparatus 40 has a wafer holding section 100 as a substrate holding section, a rotation mechanism 101, and an etching solution supply section 102.

[0037] The wafer holding section 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 section 100 is not limited to the illustrated example. For example, the wafer holding section 100 may include a chuck for adsorbing and holding the polymerized wafer T from below. The rotation mechanism 101 rotates the polymerized wafer T (the first wafer W) held by the wafer holding section 100 about a vertical rotation center line 100a.

[0038] The etching liquid supply unit 102 has, as an example, a nozzle that supplies the etching liquid E to the back surface Wb of the first wafer W held by the wafer holding unit 100. The etching liquid 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 moving mechanism 103. In one example, the etching liquid 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, through the upper part of the center of the first wafer W as shown in FIG. 4. In the following description, one reciprocating movement of the etching liquid supply unit 102 is defined as one loop.

[0039] The etching liquid 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, the etching liquid E may contain phosphoric acid or sulfuric acid. Note that the etching target is not limited to the first wafer W and may be, for example, amorphous silicon. Also, the etching target in this 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 the 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 reciprocally moving the etching liquid supply unit 102, scan etching is performed in which the etching liquid is supplied from the etching liquid supply unit 102 to the back surface Wb of the first wafer W. In this embodiment, a prediction model is used to predict the etching amount distribution in the 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 the etching solution supply unit 102 is reciprocally moved 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 reciprocally moves 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 : The etching amount when the etching solution supply unit 102 is reciprocally moved, ER ref : The etching amount when the etching solution supply unit 102 is not reciprocally moved, Ratio scan : The scan ratio, R: The position from the center of the first wafer W, T: The non-discharge time when the etching solution E is not supplied, C: A constant, S: The rotation speed when rotating the first wafer W, V: The scan speed when the etching solution supply unit 102 is reciprocally moved, L: The scan width when the etching solution supply unit 102 is reciprocally moved.

[0043] The functions in each of the above formulas (3) to (5) are determined by analyzing the learning data. For example, the dummy wafer is etched with 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 reciprocally moving the etching liquid supply unit 102, and the scan width L of the etching liquid supply unit 102 are changed to etch the dummy wafer. At this time, the processing time for etching each dummy wafer is the same.

[0044] The 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 the 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] FIG. 6 is an example of the learning data obtained. 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. In this way, the etching amount distribution was obtained 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 description, the case where the learning data is obtained by etching a dummy wafer has been described as an example. However, the etching target when obtaining the learning data is not limited to the dummy wafer. Specifically, for example, the etching processing 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 film may be used as the etching target, and the etching processing 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 when the etching liquid supply unit 102 is fixed and does not reciprocate (hereinafter, sometimes referred to as "no scan"), the etching amount distribution 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 starting from the scan width L fluctuates, 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 in the case of no 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 in the case of no scan can be used as a reference.

[0050] Next, the inventors separated the variation in the etching amount distribution in scan etching. Specifically, from the concept that there exists a reference etching amount distribution without scanning, the ratio of the etching amount distribution of scan etching to the reference etching amount distribution was defined as the scan ratio Ratio scan by the following formula (7). This scan ratio Ratio scan enables the quantitative separation of the effect of scan etching. 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 scan etching can be quantitatively separated and grasped. And 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)×Ratio scan (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 in 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 reciprocally moving the etching liquid supply unit 102, L: Scan width when reciprocally moving the etching liquid supply unit 102.

[0052] Next, the inventors investigated 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 in FIG. 10 indicates the non-discharge time T, and the vertical axis indicates the scan ratio Ratio scan . Referring to FIG. 10, the scan ratio Ratio scan decreases exponentially with respect to the non-discharge time T 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 during which the etching liquid 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 attenuation curve, b1 is the attenuation rate (slope) of the attenuation curve, and b2 is the attenuation delay value of the attenuation 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 attenuation not occurring immediately is significant. C is the asymptote of the attenuation curve. For example, when there is no C, 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 will not become 0 (zero). C is a correction term for correcting this phenomenon. Also, C can be determined, for example, after once analyzing with the above formula (2), by setting C = 0 if C < 0 and leaving C as it is if C > 0.

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

[0055] Also, the scale b0, the attenuation rate b 1、 and the attenuation 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: The rotation speed when rotating the first wafer W, V: The 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 (prediction model of etching amount distribution) 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] Figure 11 is a graph comparing the measured values of the etching amount distribution obtained by experiments (thick line in Figure 11) with the calculated values of the etching amount distribution calculated from the constant-speed scan model (thin line in Figure 11). The rotation speed S was changed from S1 to S4, the scan speed V was changed from V1 to V3, and the scan width L was changed from L1 to L4. The measured values and the calculated values are substantially in agreement, and it was confirmed that the constant-speed scan model of the above formulas (1) to (6) is appropriate.

[0059] Next, the wafer processing performed using the wafer processing system 1 configured as described above will be explained. 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 at the peripheral edge of the first wafer W.

[0060] 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.

[0061] 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).

[0062] 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. 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.

[0063] 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). A detailed method for determining the optimum etching conditions in the control device 90 will be described later.

[0064] The measured thickness of the polymerized wafer T of the first wafer W is then transported to the cleaning device 60 by the wafer transport device 70 or the wafer transport device 50. In 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, in the cleaning device 60, the back surface Sb of the second wafer S may be cleaned as described above. When measuring the thickness after grinding with 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 with the cleaning device 60, the thickness of the first wafer W may be measured with the thickness measuring device 61, and the optimum etching conditions in the etching process may be determined.

[0065] Next, the polymerized wafer T is transported to the etching device 40 by the wafer transport device 50. In the etching device 40, the back surface Wb, which is the ground surface of the first wafer W, is etched with the etching solution E under the optimum etching conditions (step S5 in FIG. 12).

[0066] 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 solution E from the etching solution supply portion 102 is started to start etching the back surface Wb.

[0067] Furthermore, when etching the first wafer W, while continuing the supply of the etching solution E from the etching solution supply portion 102, as shown in FIG. 4, the etching solution supply portion 102 is reciprocally moved (scanned) with the rotation center line 100a passing through the rotation center of the first wafer W, that is, with the rotation center line 100a as the midpoint above the rotation center. Details of the determination method of etching conditions such as the rotation speed of the first wafer W, the scan speed when reciprocally moving the etching solution supply portion 102, and the scan width of the etching solution supply portion 102 will be described later.

[0068] When the desired etching amount is obtained on the first wafer W, the supply of the etching solution E from the etching solution supply unit 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 unit 100 (the first wafer W) is stopped, and the etching of the first wafer W is terminated.

[0069] Here, the optimum 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 optimum etching conditions are determined based on the difference between the actually 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 (hereinafter referred to as "target shape") of the first wafer W after etching. Then, in step S5, by etching the first wafer W under the optimum etching conditions, the difference between the actually 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 target surface shape of the first wafer W can be appropriately obtained regardless of the surface shape of the first wafer W after grinding.

[0070] 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 after etching of the first wafer W (polymerized wafer T) is obtained by measuring the thickness of the first wafer W 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 in the wafer processing system 1 next. 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.

[0071] Thereafter, the polymerized wafer T that has been subjected to 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 are completed.

[0072] Next, a detailed method for determining the above-described optimal etching conditions (step S3 in FIG. 12) will be described.

[0073] First, when determining the optimal etching conditions, prior to processing the polymer 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).

[0074] In step S3-1, as described above, for example, etching is performed on a dummy wafer under a constant-speed scan sequence, and learning data regarding the etching amount distribution shown in FIG. 6 is acquired.

[0075] In step S3-2, as described above, a prediction model of the etching amount distribution, that is, a constant-speed scan 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) = 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 : The etching amount when the etching liquid supply unit 102 is reciprocated, ER ref : The etching amount when the etching liquid supply unit 102 is not reciprocated, Ratio scan : The scan ratio, R: The position from the center of the first wafer W, T: Non-discharge time when etching solution E is not supplied C: Constant S: Rotation speed when rotating the first wafer W V: Scan speed when reciprocating the etching solution supply unit 102 L: Scan width when reciprocating the etching solution supply unit 102

[0076] In parallel with steps S3-1 and S3-2, the target etching amount distribution in the etching process of step S5 is obtained (step S3-3 in FIG. 13). The target etching amount distribution is obtained based on the thickness distribution in the target shape of the first wafer W after etching (hereinafter referred to as the "target thickness distribution") and the thickness distribution in the surface shape of the first wafer W after grinding obtained in step S2 (hereinafter referred to as the "measured thickness distribution"). 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.

[0077] Next, an etching condition is determined in which the etching amount distribution calculated using the constant-speed scan model in step S3-2 approximates the target etching amount distribution obtained in step S3-3. The method for determining this etching condition is arbitrary, but it is determined, for example, by performing an optimization calculation such as the least squares method. Then, such an etching condition is determined as the optimum etching condition (step S3-4 in FIG. 13). Note that the optimum etching condition determined in step S3-4 corresponds to the etching condition to be predicted in the present disclosure.

[0078] Thereafter, in step S4, after cleaning the back surface Wb of the first wafer W, in step S5, the back surface Wb of the first wafer W is etched under the optimum 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 optimum etching conditions, and while moving the etching solution supply unit 102 at the determined scan speed and scan width, the etching solution E is supplied to the first wafer W.

[0079] 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.

[0080] According to the above embodiment, the etching amount distribution can be appropriately predicted using the constant speed scan 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.

[0081] Also, in step S5, the first wafer W can be etched under the optimal etching conditions determined in step S3. 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.

[0082] When the inventors actually performed simulations, in any of the cases where the target etching amount distribution was V-shaped, A-shaped, M-shaped, or W-shaped, the variation in the thickness distribution of the first wafer W after etching could be kept within an acceptable range. Also, the flatness (TTV) of the first wafer W after etching was improved compared to the prior art. The V-shaped distribution is one in which the etching amount at the center of the first wafer W is smaller than the etching amounts at both ends, and it has a substantially V-shaped pattern in a graph with the wafer position on the horizontal axis and the etching amount on the vertical axis. The A-shaped distribution is one in which the etching amount at the center of the first wafer W is larger than the etching amounts at both ends, has a substantially A-shaped pattern in the above graph, and has a shape opposite to that of the V-shaped distribution. The M-shaped distribution is one in which two A-shaped distributions are arranged with the center of the first wafer W in between in the above graph, and it has a substantially M-shaped pattern as a whole. The W-shaped distribution is one in which two V-shaped distributions are arranged with the center of the first wafer W in between in the above graph, and it has a substantially W-shaped pattern as a whole.

[0083] Also, since steps S1 to S6 are performed for each stacked wafer T, even if the surface shape before etching (after grinding in this embodiment) is different for each wafer, the surface shape of the first wafer W after etching can be controlled for each sheet to the target shape.

[0084] In the above embodiment, the case where the prediction model of the etching amount distribution is a constant-speed scan model has been described, but it is also possible to predict the etching amount distribution of scan etching performed with other scan sequences.

[0085] For example, another scan sequence to which the present disclosure is applied may be a sequence in which constant-speed scan sequences of a plurality of etching conditions are connected. Hereinafter, this scan sequence may be referred to as a "plurality of connected sequences", and the prediction model of the etching amount distribution in the plurality of connected sequences may be referred to as a "plurality of connected scan models" in some cases.

[0086] As shown in FIG. 14, the constant-speed scan sequence 1 and the constant-speed scan sequence 2 are concatenated to generate a plurality of concatenated sequences. In FIG. 14, the concatenation of the left figure (constant-speed scan sequence 1) and the right figure (constant-speed scan sequence 2) is indicated by “+”. In this example, in the constant-speed scan sequence 1 and the constant-speed scan sequence 2, the rotation speed S of the first wafer W is different, and is S1 and S2 respectively. And the plurality of concatenated scan models are derived by adding the constant-speed scan model 1 and the constant-speed scan model 2 according to the time ratio of the constant-speed scan sequence 1 and the constant-speed scan sequence 2. Note that the time ratio may be the ratio of the number of loop times.

[0087] FIG. 15 is a graph showing the etching amount distribution of each when the first wafer W is etched with the constant-speed scan sequence 1, the constant-speed scan sequence 2, and the plurality of concatenated sequences. The horizontal axis of FIG. 15 indicates the radial position from the center of the first wafer W (0 (zero) on the horizontal axis) to one outer end, and the vertical axis indicates the etching amount (etching rate).

[0088] In FIG. 15, the measured value of the etching amount distribution when etching is performed with the constant-speed scan sequence 1 is indicated by a one-dot chain line. Also, the measured value of the etching amount distribution when etching is performed with the constant-speed scan sequence 2 is indicated by a two-dot chain line.

[0089] On the other hand, Example 1 (thick solid line) shows the measured value of the etching amount distribution when the constant-speed scan sequence 1 and the constant-speed scan sequence 2 are performed at a time (number of loop times) ratio of 1:1. The thin solid line is the calculated value of the etching amount distribution under the etching conditions of Example 1. This calculated value is the sum of 1 / 2 of the etching amount distribution of the constant-speed scan model 1 and 1 / 2 of the etching amount distribution of the constant-speed scan model 2.

[0090] Example 2 (thick dashed line) shows the etching amount distribution when constant-speed scan sequences 1 and 2 are performed with a time ratio of 5:1. The thin dashed line is the calculated value of the etching amount distribution under the etching conditions of Example 2. This calculated value is obtained by adding 5 / 6 of the etching amount distribution of the constant-speed scan model 1 and 1 / 6 of the etching amount distribution of the constant-speed scan model 2.

[0091] In such a case, in both Examples 1 and 2, the measured values and the calculated values are substantially in agreement. Therefore, in the multiple-connected scan model, the etching amount distribution can be appropriately predicted. Further, comparing Example 1 and Example 2, in Example 1, the etching amount at the center of the wafer is less than that at the outer periphery, while in Example 2, the etching amount distribution is uniform within the wafer surface. In other words, by adjusting the time ratio, an arbitrary etching amount distribution can be obtained, and as a result, the surface shape of the wafer after etching can be controlled.

[0092] Note that in the above example, constant-speed scan sequences 1 and 2 with different rotation speeds S of the first wafer W were connected as the etching conditions, but constant-speed scan sequences with different other etching conditions, such as the scan speed V and scan width L of the etching solution supply unit 102, may also be connected.

[0093] For example, another scan sequence to which the present disclosure is applied may be a sequence in which the scan width L of the etching solution supply unit 102 is asymmetric from the center of the first wafer W. Hereinafter, this scan sequence is referred to as an "asymmetric scan sequence", and the prediction model of the etching amount distribution in the asymmetric scan sequence may be referred to as an "asymmetric scan model".

[0094] As shown in FIG. 16, in an asymmetric scan sequence, the scan width L from the center of the first wafer W to one end of the scan is L1, and the scan width L from the center of the first wafer W to the other end of the scan is L2. In such a case, the asymmetric scan model is derived by adding the constant-speed scan model 1 and the constant-speed scan model 2 according to the time ratio (loop count ratio) of the constant-speed scan sequence 1 with the scan width L being L1 and the constant-speed scan sequence 2 with the scan width L being L2.

[0095] FIG. 17 is a graph showing the etching amount distribution in each case when the first wafer W is etched with the constant-speed scan sequence 1, the constant-speed scan sequence 2, and the asymmetric scan sequence. The horizontal axis in FIG. 17 indicates the radial position from the center of the first wafer W (0 (zero) on the horizontal axis) to one outer end, and the vertical axis indicates the etching amount (etching rate).

[0096] In FIG. 17, the measured value of the etching amount distribution when etching is performed with the constant-speed scan sequence 1 is indicated by a dashed-dotted line. Also, the measured value of the etching amount distribution when etching is performed with the constant-speed scan sequence 2 is indicated by a two-dot chain line.

[0097] On the other hand, the example (thick solid line) shows the measured value of the etching amount distribution when the constant-speed scan sequence 1 and the constant-speed scan sequence 2 are performed at a time (loop count) ratio of 1:4. The thin solid line is the calculated value of the etching amount distribution under the etching conditions of the example. This calculated value is obtained by adding 1 / 5 of the etching amount distribution of the constant-speed scan model 1 and 4 / 5 of the etching amount distribution of the constant-speed scan model 2.

[0098] In such a case, also in the example, the measured value and the calculated value are substantially in agreement. Therefore, with the asymmetric scan model, the etching amount distribution can be appropriately predicted. As a result, the etching amount distribution can be appropriately controlled to control the surface shape of the wafer after etching.

[0099] In addition, when using an asymmetric scan model, the processing time of the scan sequence can be compressed. For example, if the time required for one loop in the constant-speed scan sequence 1 is 10 seconds and the time required for one loop in the constant-speed scan sequence 2 is 20 seconds, it takes 30 seconds to predict the etching amount distribution in the asymmetric scan sequence. On the other hand, when using the asymmetric scan model, since 0.5 loops of the constant-speed scan sequence 1 and 0.5 loops of the constant-speed scan sequence 2 can be combined, the time required to predict the etching amount distribution can be shortened to 15 seconds, which is half.

[0100] For example, another scan sequence to which the present disclosure is applied may be a sequence in which the scan speed V of the etching solution supply unit 102 changes in the radial direction of the first wafer W. That is, when the etching solution supply unit 102 moves from the center of the first wafer W to the scan end, the scan speed V changes at the speed change point in the radial direction of the first wafer W. Hereinafter, this scan sequence is referred to as a "variable-speed scan sequence", and the prediction model of the etching amount distribution in the variable-speed scan sequence may be referred to as a "variable-speed scan model".

[0101] As shown in FIG. 18, in the variable-speed scan sequence, the first scan speed V1 is in the range from the center of the first wafer W to the scan width L1 (speed change point), and the second scan speed V2 is in the range from the scan width L1 to the scan width L2 (scan end). In such a case, the variable-speed scan model is derived by combining the constant-speed scan model 1 in which the scan speed V is V1 and the constant-speed scan model 2 in which the scan speed V is V2.

[0102] FIG. 19 is an explanatory diagram showing the change over time of the position of the etching solution supply unit 102 in the variable-speed scan sequence. The horizontal axis in FIG. 19 indicates the radial position from the center of the first wafer W (0 (zero) on the horizontal axis) to one outer end, and the vertical axis indicates the elapsed time.

[0103] In such a case, as shown in FIG. 20, in the variable-speed scan sequence, the range of the scan width L1 from the center of the first wafer W matches the constant-speed scan sequence of the scan width L3. Therefore, in the variable-speed scan model, in the range of the scan width L1 from the center of the first wafer W, the constant-speed scan model 1 of the first scan speed V1 and the etching conditions of the scan width L3 is applied.

[0104] Also, as shown in FIG. 21, in the variable-speed scan sequence, the range from the scan width L1 to the scan width L2 matches half of the constant-speed scan sequence of the scan width L2. Therefore, in the variable-speed scan model, in the range from the scan width L1 to the scan width L2, the constant-speed scan model 2 in which the etching amount distribution is half of the constant-speed scan sequence of the second scan speed V2 and the etching conditions of the scan width L2 is applied.

[0105] FIG. 22 is a graph showing the etching amount distribution when the first wafer W is etched in the variable-speed scan sequence and the etching amount distribution calculated by the variable-speed scan model (constant-speed scan model 1, constant-speed scan model 2). The horizontal axis of FIG. 22 indicates the radial position from the center of the first wafer W (0 (zero) on the horizontal axis) to one outer end, and the vertical axis indicates the etching amount (etching rate).

[0106] In FIG. 22, the solid line indicates the measured value of the etching amount distribution when the first wafer W is etched in a variable speed scan sequence. The dotted line indicates the etching amount distribution calculated by the constant speed scan model 1, and the dashed-dotted line indicates the etching amount distribution calculated by the constant speed scan model 2. In such a case, in the range of the scan width L1 from the center of the first wafer W, the measured value and the calculated value of the constant speed scan model 1 are substantially in agreement. Also, in the range from the scan width L1 to the scan width L2, the measured value and the calculated value of the constant speed scan model 2 are substantially in agreement. Therefore, in the variable speed scan model, by applying the constant speed scan model 1 from the center of the first wafer W to the scan width L1 and applying the constant speed scan model 2 from the scan width L1 to the scan width L2, the etching amount distribution can be appropriately predicted. As a result, the etching amount distribution can be appropriately controlled to control the surface shape of the wafer after etching.

[0107] Note that, as shown in FIG. 23, the intersection of the etching amount distribution of the constant speed scan model 1 and the etching amount distribution of the constant speed scan model 2 may deviate from the position (speed change point) of the scan width L1. In such a case, the constant speed scan model 1 and the constant speed scan model 2 may be combined with the intersection as a boundary.

[0108] Also, the deviation between the intersection of the etching amount distribution of the constant speed scan model 1 and the etching amount distribution of the constant speed scan model 2 described above and the speed change point is due to the fact that the etching amount changes suddenly when the scan speed changes suddenly. Therefore, the etching amount distribution of the constant speed scan model 1 or the constant speed scan model 2 may be corrected according to the difference between the first scan speed V1 and the second scan speed V2. By correcting the boundary conditions in this way, the etching amount distribution can be predicted more appropriately.

[0109] The variable-speed scan sequence is useful for making the etching amount distribution uniform within the wafer surface and flattening the surface shape of the first wafer W. For example, when the etching liquid supply unit 102 is fixed (when there is no scan), as described above, the surface of the central portion of the first wafer W protrudes upward compared to the surface of the outer peripheral portion. In this regard, in the constant-speed scan sequence, the protrusion of the surface of the central portion of the first wafer W can be suppressed, but by performing the variable-speed scan sequence, the surface shape of the first wafer W can be further flattened.

[0110] In the above embodiments, the constant-speed scan model, the multiple-connected scan model, the asymmetric scan model, and the variable-speed scan model have been described respectively. However, a prediction model may be constructed by combining any one or all of these, and the etching amount distribution may be predicted. In such a case, the etching amount distribution can be arbitrarily controlled.

[0111] In the above embodiments, in the polymerized wafer T in which the first wafer W and the second wafer S are bonded, the case where various processes are performed on the back surface Wb of the first wafer W has been described as an example. However, 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 a titanium nitride. In such a case, the etching liquid supply unit 102 in the etching apparatus 40 may be configured to be arbitrarily switchable to supply different types of etching liquids 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 embodiments.

[0112] 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.

[0113] In addition, 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 to this. 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. Also, for example, the technology of the present disclosure can be applied even when etching a wafer in a single etching device.

[0114] In the above embodiment, the first wafer W is thinned by the processing device 80, but the thinning method is not limited to this. For example, the thinning process of the first wafer W includes polishing the back surface Wb of the first wafer W. Alternatively, for example, it 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, instead of the processing device 80, a laser processing device (not shown) for forming the modified layer (not shown) is provided in the wafer processing system 1.

[0115] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The above embodiments may be omitted, replaced, or changed in various forms without departing from the scope and gist of the appended claims.

Explanation of Reference Numerals

[0116] 1 Wafer processing system 40 Etching device 90 Control device 100 Wafer holding unit 101 Rotation mechanism 102 Etching solution supply unit 103 Moving mechanism E Etching solution T Polymerized wafer W First wafer S Second wafer

Claims

1. A substrate processing method for processing a substrate, comprising: rotating an etching target on the substrate, and while reciprocating the etching liquid supply unit in the radial direction through above the rotation center of the etching target, supplying an etching liquid from the etching liquid supply unit to the surface of the etching target to etch the surface; predicting an etching amount distribution in the radial direction of the etching target when etching the surface of the etching target under predicted etching conditions; The prediction of the etching amount distribution includes: acquiring learning data including etching amount distributions when etching the surface of the etching target under a plurality of different etching conditions; predicting the etching amount distribution under the predicted etching conditions from the following formulas (1) to (6) using the learning data. A substrate processing method. ER ｓｃａｎ (R) = ER ｒｅｆ (R) × Ratio ｓｃａｎ (R) ··· (1) Ratio ｓｃａｎ (R) = b ０ × exp(b １ × T + b ２ ) + C...(2) b ０ = f(S, V) ... (3) b １ = f(S, V) ... (4) b ２ = f(S, V) ... (5) T = (L - R) / V... (6) where: 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, R: position from the center of the etching target; T: non-discharge time when the etching liquid is not supplied; C: constant; S: rotation speed when rotating the etching target; V: scan speed when reciprocating the etching liquid supply unit; L: scan width when reciprocating the etching liquid supply unit.

2. The function in each of the above formulas (3) to (5) is determined by analyzing the learning data. The substrate processing method according to Claim 1.

3. Adding the etching amount distributions predicted by the above formulas (1) to (6) for different predicted etching conditions according to the etching time ratio under the different predicted etching conditions to derive the etching amount distribution. The substrate processing method according to Claim 1 or 2.

4. When the etching liquid supply unit reciprocates asymmetrically with respect to the rotation center of the etching target, Adding the etching amount distributions predicted by the above formulas (1) to (6) for different scan widths according to the etching time ratio at the different scan widths to derive the etching amount distribution. The substrate processing method according to Claim 1 or 2.

5. When the etching liquid supply unit moves from the rotation center of the etching target to the scan end, and the scan speed changes at a speed change point in the radial direction of the etching target, Combining the etching amount distribution predicted by the above formulas (1) to (6) for the first scan speed from the rotation center to the shift point with the etching amount distribution predicted by the above formulas (1) to (6) for the second scan speed from the shift point to the scan end, and deriving the etching amount distribution, the substrate processing method according to claim 1 or 2.

6. At the shift point, correcting either one of the etching amount distribution predicted by the above formulas (1) to (6) for the first scan speed or the etching amount distribution predicted by the above formulas (1) to (6) for the second scan speed according to the first scan speed and the second scan speed, the substrate processing method according to claim 5.

7. Before etching the surface of the object to be etched, measuring the thickness of the object to be etched to obtain the thickness distribution in the radial direction of the object to be etched, Predicting the etching amount distribution based on the obtained thickness distribution of the object to be etched, the substrate processing method according to claim 1 or 2.

8. A substrate processing system for processing a substrate, A substrate holding unit for holding the substrate, A rotation mechanism for rotating the substrate holding unit, An etching liquid supply unit for supplying an etching liquid from above the surface of the object to be etched on the substrate held by the substrate holding unit, An etching apparatus including a moving mechanism for moving the etching liquid supply unit in the horizontal direction, A control device, The control device, Rotating the object to be etched and supplying the etching liquid from the etching liquid supply unit to the surface of the object to be etched to etch the surface while reciprocating the etching liquid supply unit in the radial direction through above the rotation center of the object to be etched, Predicting 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 the etching conditions to be predicted, The prediction of the etching amount distribution, Obtaining learning data including the etching amount distribution when etching the surface of the object to be etched under a plurality of different etching conditions, Predicting the etching amount distribution under the etching conditions to be predicted from the following formulas (1) to (6) using the learning data, a substrate processing system. ER ｓｃａｎ (R) = ER ｒｅｆ (R) × Ratio ｓｃａｎ (R) ··· (1) Ratio ｓｃａｎ (R) = b ０ × exp(b １ × T + b ２ ) + C...(2) b ０ = f(S, V) ... (3) b １ = f(S, V) ... (4) b ２ = f(S, V) ... (5) T = (L - R) / V... (6) However, 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, R: Position from the center of the object to be etched T: Non-discharge time during which the etching solution is not supplied C: Constant S: Rotation speed when rotating the object to be etched V: Scan speed when reciprocally moving the etching solution supply unit L: Scan width when reciprocally moving the etching solution supply unit

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

10. The control device adds the etching amount distributions predicted by the above formulas (1) to (6) for different prediction target etching conditions according to the etching time ratio under the different prediction target etching conditions, and derives the etching amount distribution. The substrate processing system according to claim 8 or 9.

11. The control device When the etching solution supply unit reciprocally moves asymmetrically with respect to the rotation center of the object to be etched The control device adds the etching amount distributions predicted by the above formulas (1) to (6) for different scan widths according to the etching time ratio at the different scan widths, and derives the etching amount distribution. The substrate processing system according to claim 8 or 9.

12. The control device When the etching solution supply unit moves from the rotation center of the object to be etched to the scan end, and the scan speed changes at the shift point in the radial direction of the object to be etched The control device combines the etching amount distribution predicted by the above formulas (1) to (6) for the first scan speed from the rotation center to the shift point and the etching amount distribution predicted by the above formulas (1) to (6) for the second scan speed from the shift point to the scan end, and derives the etching amount distribution. The substrate processing system according to claim 8 or 9.

13. At the shift point, the control device corrects either one of the etching amount distribution predicted by the above formulas (1) to (6) for the first scan speed or the etching amount distribution predicted by the above formulas (1) to (6) for the second scan speed according to the first scan speed and the second scan speed. The substrate processing system according to claim 12.

14. It has a thickness measurement device for measuring the thickness of the object to be etched before etching The substrate processing system according to claim 8 or 9, wherein the control device predicts the etching amount distribution based on the thickness distribution of the etching target obtained from the thickness of the etching target measured by the thickness measuring device.

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