Substrate processing method and substrate processing system

Abstract

Provided is a substrate processing method for processing a substrate, the substrate processing method involving: on the basis of set etching conditions, supplying an etching liquid containing at least one of hydrofluoric acid, phosphoric acid, and nitric acid to the surface of the substrate and etching the surface of the substrate; deriving actual etching amounts at a plurality of reference points on the surface of the substrate after etching; comparing, for each reference point, a preset threshold with the difference between the actual etching amount and a normal etching amount acquired in advance; and determining, on the basis of the comparison result, the state of the actual etching amount and the state of an etching liquid supply environment for supplying the etching liquid to the surface of the substrate. The normal etching amount is an etching amount at each among the plurality of reference points acquired when the surface of the substrate is etched in advance under the set etching conditions, and the etching is performed normally.

Description

Substrate Processing Method and Substrate Processing System

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

[0002] Patent Document 1 discloses a substrate processing method including supplying an etching solution containing hydrofluoric acid and phosphoric acid to the surface of a substrate to etch the surface, recovering the etching solution after etching, and selecting and adding at least hydrofluoric acid or phosphoric acid to the recovered etching solution after etching to adjust the composition ratio of the etching solution.

[0003] International Publication No. 2023 / 026828

[0004] The technology according to the present disclosure appropriately determines the presence or absence of an abnormality when etching the surface of a substrate.

[0005] One aspect of the present disclosure is a substrate processing method for processing a substrate, including supplying an etching solution containing at least one of hydrofluoric acid, phosphoric acid, and nitric acid to the surface of the substrate based on set etching conditions to etch the surface of the substrate, deriving the actual etching amounts of a plurality of reference points on the surface of the substrate after etching, comparing, for each of the reference points, the difference between the actual etching amount and a previously obtained normal etching amount with a preset threshold value, and determining, based on the result of the comparison, the state of the actual etching amount and the state of the etching solution supply environment for supplying the etching solution to the surface of the substrate. The normal etching amount is the etching amounts of the plurality of reference points obtained when the surface of the substrate is etched under the set etching conditions in advance and the etching is performed normally.

[0006] According to the present disclosure, the presence or absence of an abnormality when etching the surface of a substrate can be appropriately determined.

[0007] This is a plan view showing the general configuration of the wafer processing system. This is a side view showing the general configuration of the etching apparatus. This is an explanatory diagram showing how the nozzle moves radially. This is a flow chart showing the main processes of wafer processing. This is a flow chart showing the main processes of determining the optimal etching conditions. This is a flow chart showing the main processes of determining the state of the wafer etching amount and the state of the etching solution supply environment. This is an explanation showing the change in the etching amount distribution over time when the wafer surface is etched under multiple different etching conditions. This is an explanatory diagram showing the change in the etching amount distribution when the hydrofluoric acid concentration of the etching solution is changed.

[0008] Hereinafter, the wafer processing system as a substrate processing system and the wafer processing method as a substrate processing method according to this embodiment will be described with reference to the drawings. In this specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant explanations will be omitted.

[0009] In the wafer processing system 1 according to this embodiment, a wafer W, which is a substrate obtained by cutting from an ingot, is subjected to a process to improve the in-plane uniformity of its thickness. Hereinafter, the cut surfaces of the wafer W are referred to as the first surface Wa and the second surface Wb. The first surface Wa is the surface opposite to the second surface Wb. In addition, the first surface Wa and the second surface Wb are sometimes collectively referred to as the surface of the wafer W.

[0010] As shown in Figure 1, the wafer processing system 1 has a configuration in which an loading / unloading station 2 and a processing station 3 are integrally connected. At the loading / unloading station 2, for example, a hoop F capable of accommodating multiple wafers W is loaded and unloaded to and from the outside. The processing station 3 is equipped with various processing devices that perform desired processing on the wafers W.

[0011] The loading / unloading station 2 is provided with a hoop mounting table 10 on which multiple hoops F, for example, three hoops F, are placed. Adjacent to the hoop mounting table 10, on the negative X-axis side, is a wafer transport device 20. The wafer transport device 20 is configured to move freely along a transport path 21 extending in the Y-axis direction. The wafer transport device 20 also has, for example, two transport arms 22 that hold and transport wafers W. Each transport arm 22 is configured to move freely in the horizontal direction, vertical direction, around the horizontal axis, and around the vertical axis. Note that the configuration of the transport arms 22 is not limited to this embodiment and can be any configuration. The wafer transport device 20 is configured to transport wafers W to the hoops F on the hoop mounting table 10 and to the transition device 30 described later.

[0012] At the loading / unloading station 2, a transition device 30 is provided adjacent to the wafer transport device 20 on the negative X-axis side of the wafer transport device 20 for transferring wafers W to and from the processing station 3.

[0013] The processing station 3 is provided with, for example, three processing blocks G1 to G3. The first processing block G1, the second processing block G2, and the third processing block G3 are arranged in this order from the positive X-axis side (towards the loading / unloading station 2) to the negative X-axis side.

[0014] The first processing block G1 is equipped with an etching apparatus 40, a thickness measuring device 50, an inversion device 51, and a wafer transport device 60. The etching apparatus 40, the thickness measuring device 50, and the inversion device 51 are arranged in a stacked configuration. However, the number and arrangement of the etching apparatus 40, the thickness measuring device 50, and the inversion device 51 are not limited to this.

[0015] The etching apparatus 40 etches the silicon (Si) on the first surface Wa or the second surface Wb after grinding by the grinding apparatus 90 described later. Multiple etching apparatuses 40 may be provided to improve the throughput of wafer processing. The configuration of the etching apparatus 40 will be described later.

[0016] The thickness measuring device 50, in one example, comprises a measuring unit (not shown) and a calculation unit (not shown). The measuring unit includes sensors that measure the thickness of the wafer W after etching at multiple points. The measuring unit can measure the thickness of the wafer W at any reference point on the wafer W. The calculation unit obtains the thickness distribution of the wafer W from the measurement results (thickness of the wafer W) obtained by the measuring unit, and further calculates the thickness deviation of the wafer W (TTV: Total Thickness Variation). The thickness deviation of the wafer W is the maximum value of the difference between the thickness of the target shape and the measured thickness. Note that the calculation of the thickness distribution and thickness deviation of the wafer W may be performed by the control device 130 described later instead of the calculation unit. In other words, the calculation unit (not shown) may be provided within the control device 130 described later. Note that the configuration of the thickness measuring device 50 is not limited to this and can be configured arbitrarily.

[0017] The inversion device 51 inverts the first surface Wa and the second surface Wb of the wafer W in the vertical direction. The configuration of the inversion device 51 is arbitrary.

[0018] The wafer transfer device 60 is located on the negative X-axis side of the transition device 30. The wafer transfer device 60 has, for example, two transfer arms 61 that hold and transfer the wafer W. Each transfer arm 61 is configured to be movable in the horizontal direction, vertical direction, around the horizontal axis, and around the vertical axis. The wafer transfer device 60 is configured to transfer the wafer W to the transition device 30, etching device 40, thickness measuring device 50, inversion device 51, cleaning device 70 (described later), thickness measuring device 71 (described later), buffer device 72 (described later), and inversion device 73 (described later).

[0019] The second processing block G2 is equipped with a cleaning device 70, a thickness measuring device 71, a buffer device 72, an inversion device 73, and a wafer transport device 80. The cleaning device 70, the thickness measuring device 71, the buffer device 72, and the inversion device 73 are arranged in a stacked configuration. However, the number and arrangement of the cleaning device 70, the thickness measuring device 71, the buffer device 72, and the inversion device 73 are not limited to these.

[0020] The cleaning device 70 cleans at least the first surface Wa or the second surface Wb after grinding in the grinding device 90 described later.

[0021] In one example, the thickness measuring device 71 has the same configuration as the thickness measuring device 50 described above. However, the configuration of the thickness measuring device 71 is not limited to this and can be configured arbitrarily.

[0022] The buffer device 72 temporarily holds the wafer W before processing, which is being transferred from the first processing block G1 to the second processing block G2. The configuration of the buffer device 72 is arbitrary. The buffer device 72 may also have an alignment mechanism (not shown) that adjusts at least one of the central position of the wafer W relative to the chucks 93a and 93b described later, or the horizontal orientation of the wafer W.

[0023] The inversion device 73 inverts the first surface Wa and the second surface Wb of the wafer W in the vertical direction. The configuration of the inversion device 73 is arbitrary.

[0024] The wafer transport device 80 is positioned, for example, on the positive Y-axis side of the cleaning device 70, thickness measuring device 71, buffer device 72, and inversion device 73. The wafer transport device 80 has, for example, two transport arms 81 that transport wafers W by adsorption and holding them with an adsorption holding surface (not shown). Each transport arm 81 is supported by a multi-joint arm member 82 and is configured to be movable in the horizontal direction, vertical direction, around the horizontal axis, and around the vertical axis. The wafer transport device 80 is configured to transport wafers W to the etching device 40, thickness measuring device 50, inversion device 51, cleaning device 70, thickness measuring device 71, buffer device 72, inversion device 73, and the grinding device 90 described later.

[0025] The third processing block G3 is equipped with a grinding device 90. The grinding device 90 grinds and flattens the first surface Wa or the second surface Wb of the wafer W.

[0026] The grinding apparatus 90 has a rotary table 91. The rotary table 91 is configured to rotate freely around a vertical rotation centerline 92 by a rotation mechanism (not shown). A total of four chucks 93a and 93b for adsorbing and holding wafers W are provided on the rotary table 91. Porous chucks, for example, are used for the chucks 93a and 93b. The surfaces of the chucks 93a and 93b, i.e., the wafer holding surfaces, have a convex shape in which the central part protrudes more than the outer periphery when viewed from the side.

[0027] Of the four chucks 93a and 93b, the two first chucks 93a are used for grinding at the first machining position B1, which will be described later. These two first chucks 93a are positioned symmetrically with respect to the rotation centerline 92. The remaining two second chucks 93b are used for grinding at the second machining position B2, which will be described later. These two second chucks 93b are also positioned symmetrically with respect to the rotation centerline 92. In other words, the first chucks 93a and the second chucks 93b are arranged alternately in the circumferential direction.

[0028] The four chucks 93a and 93b are movable to the transfer positions A1 to A2 and the machining positions B1 to B2 as the rotary table 91 rotates. In addition, each of the four chucks 93a and 93b is configured to rotate around a vertical axis by a rotation mechanism (not shown). Furthermore, each of the four chucks 93a and 93b is configured to adjust the relative inclination between the grinding surfaces of the grinding sections 101 and 111 at the machining positions B1 to B2 (described later) and the upper surfaces of the chucks 93a and 93b by an inclination adjustment mechanism (not shown).

[0029] The first transfer position A1 is located on the positive X-axis and positive Y-axis side with respect to the rotation centerline 92 of the rotary table 91, and the wafer W is transferred to the first chuck 93a when grinding the first surface Wa.

[0030] The second transfer position A2 is located on the positive X-axis side and the negative Y-axis side with respect to the rotation centerline 92 of the rotary table 91, and the wafer W is transferred to the second chuck 93b when grinding the second surface Wb.

[0031] The first processing position B1 is located on the negative X-axis and negative Y-axis side with respect to the rotation centerline 92 of the rotary table 91, and the first grinding unit 100 is positioned there. The first grinding unit 100 has a grinding section 101 equipped with an annular, rotatable grinding wheel (not shown). The grinding section 101 is also configured to move vertically along the support column 102. As an example, the first grinding unit 100 grinds the first surface Wa or the second surface Wb of a wafer W held in the first chuck 93a.

[0032] The second processing position B2 is located on the negative X-axis side and positive Y-axis side with respect to the rotation centerline 92 of the rotary table 91. The second grinding unit 110 is positioned at this location and has a grinding section 111 equipped with an annular, rotatable grinding wheel (not shown). The grinding section 111 is also configured to be movable vertically along the support column 112. As an example, the second grinding unit 110 grinds the second surface Wb or the first surface Wa of the wafer W held in the second chuck 93b.

[0033] As described above, the holding surfaces of the chucks 93a and 93b have a convex shape. Therefore, in the wafer grinding process using the grinding units 100 and 110, the annularly arranged grinding wheels contact the wafer W from the center to the outer edge in an arc shape. By rotating the chucks 93a and 93b and the grinding wheels respectively in this state, the entire surface of the wafer W is ground.

[0034] Furthermore, in the grinding units 100 and 110, the shape of the wafer W after grinding can be controlled to be flat, convex (convex or A-shaped), concave (concave or V-shaped), W-shaped, M-shaped, or a combination of any two of these shapes by adjusting the relative angle (inclination) between the holding surfaces of the chucks 93a and 93b and the grinding surface of the grinding wheel. The flat shape is a shape in which the entire surface of the wafer W is adjusted to be below a desired thickness deviation (TTV), preferably a shape in which the thickness is uniformly controlled across the entire surface. The convex shape is a shape in which the thickness in the center of the wafer W is greater than the thickness in the outer periphery. The concave shape is a shape in which the thickness in the concave part of the wafer W is smaller than the thickness in the outer periphery. The W-shaped shape is a shape in which the thickness at the center of the radius is smaller than the thickness in the center and outer periphery of the wafer W. The M-shaped shape is a shape in which the thickness at the center of the radius is larger than the thickness in the center and outer periphery of the wafer W.

[0035] Furthermore, thickness measuring devices (not shown) for measuring the thickness of the wafer W after grinding may be provided at the handover positions A1, A2 or the processing positions B1, B2.

[0036] The wafer processing system 1 described above is provided with a display panel 120. The display panel 120 may be, for example, a monitor or a touch panel, and may be directly attached to the wafer processing system 1 or it may be accessible remotely. The display panel 120 displays screens for operating each process performed by the wafer processing system 1. Signals of the operation results on the display panel 120 are output to the control device 130, which will be described later. The display panel 120 also displays information output from the control device 130, which will be described later, such as a warning of an abnormality in the etching solution supply environment and the cause of the abnormality in the etching solution supply environment, which will be described later.

[0037] The wafer processing system 1 described above is provided with at least one control device 130. The control device 130 processes computer-executable instructions that cause the wafer processing system 1 to perform the various processes described herein. The control device 130 may be configured to control each element of the wafer processing system 1 to perform the various processes described herein. In one embodiment, some or all of the control device 130 may be included in the wafer processing system 1. The control device 130 may include a processing unit, a storage unit, and a communication interface. The control device 130 is implemented, for example, by a computer. The processing unit may be configured to read a program from the storage unit that provides logic or routines that enable various control operations, and to perform various control operations by executing the read program. This program may be stored in the storage unit in advance, or it may be retrieved via a medium when needed. The retrieved program is stored in the storage unit and read from the storage unit and executed by the processing unit. The medium may be various storage media read by a computer, or it may be a communication line connected to a communication interface. The storage medium may be temporary or non-temporary. The processing unit may be a CPU (Central Processing Unit) and may consist of one or more circuits. The storage unit may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface may communicate with the wafer processing system 1 via a communication line such as a LAN (Local Area Network).

[0038] Next, the configuration of the etching apparatus 40 described above will be explained.

[0039] As shown in Figure 2, the etching apparatus 40 has a wafer holding section 200 for holding a wafer W. The wafer holding section 200 holds the outer edge of the wafer W at multiple points, for example, three points. The configuration of the wafer holding section 200 is not limited to the illustrated example; for example, the wafer holding section 200 may include a chuck (not shown) for holding the wafer W from below by suction. The wafer holding section 200 is configured to be rotatable about a vertical rotation center line 200a by a rotation mechanism 201, thereby enabling the wafer W held on the wafer holding section 200 to rotate.

[0040] A cup 210 is provided around the wafer holding section 200. The cup 210 is provided so as to surround the wafer holding section 200 and collects the etching solution E as described later. A drain line 211 for discharging the collected etching solution E is connected to the cup 210. In this embodiment, the cup 210 does not move up or down, but it may be configured to move up and down by a lifting mechanism (not shown). In addition, multiple drain lines 211 may be provided, and a switching mechanism (not shown) may be used to switch between collecting and discharging the etching solution E and the rinse solution after etching. The rinse solution is used to clean the wafer W after etching. In this case, in addition to the etching solution supply nozzle 220 described later, a rinse solution supply nozzle (not shown) is provided.

[0041] A nozzle 220, which serves as an etching solution supply unit, is provided above the wafer holding unit 200. The nozzle 220 supplies etching solution E to the first surface Wa or the second surface Wb of the wafer W held by the wafer holding unit 200. The nozzle 220 is configured to be movable in the horizontal and vertical directions by a moving mechanism 221. In one example, the nozzle 220 is configured to be able to reciprocate (scan) or pivot through the rotation centerline 200a of the wafer holding unit 200, that is, through the area above the center of the wafer W as shown in Figure 3.

[0042] The etching solution E contains hydrofluoric acid (HF) and phosphoric acid (H) to properly etch the silicon on the wafer W that may be etched. ３ PO ４ ) and nitric acid (HNO３ At least one of them is included. In one example, the etching solution E contains hydrofluoric acid, phosphoric acid, nitric acid, and water as treatment liquids, that is, it is a mixed solution of a plurality of treatment liquids. Note that the etching target may be, for example, amorphous silicon. Further, the etching target of the present embodiment can also be applied to the case of processing a wafer on which grinding treatment by the grinding device 90 is not performed. For example, when a film is formed on the first surface Wa or the second surface Wb, the film also becomes an etching target.

[0043] A liquid supply line 222 is connected to the nozzle 220, and an etching solution supply device 300 is connected to the liquid supply line 222. The etching solution supply device 300 supplies the etching solution E to the nozzle 220 through the liquid supply line 222.

[0044] In the present embodiment, the etching solution E is reused for the etching process of the wafer W. That is, for example, the etching solution E used for etching the first surface Wa or the second surface Wb of one wafer W is recovered and reused for etching the first surface Wa or the second surface Wb of the next wafer W. The above drain line 211 is connected to the etching solution supply device 300, and the etching solution E recovered by the cup 210 is discharged to the etching solution supply device 300 through the drain line 211. That is, the etching solution supply device 300 also functions as a reuse device for the etching solution E.

[0045] The etching solution supply device 300 has a tank 310 for storing the etching solution E inside. The drain line 211 and the liquid supply line 222 are connected to the tank 310.

[0046] A pump 320 is provided in the drain line 211. The pump 320 sends the used etching solution E recovered by the cup 210 to the tank 310 through the drain line 211.

[0047] A pump 330 and a valve 331 are provided in the liquid supply line 222 in this order from the tank 310 side. The pump 330 sends the etching solution E from the tank 310 to the nozzle 220. The valve 331 controls the supply of the etching solution E.

[0048] Tank 310 is connected to a hydrofluoric acid supply line 340, a phosphoric acid supply line 350, a nitric acid supply line 360, and a water supply line 370. A hydrofluoric acid supply source 341 is connected to the hydrofluoric acid supply line 340, and hydrofluoric acid is supplied from the hydrofluoric acid supply source 341 to tank 310 via the hydrofluoric acid supply line 340. A valve 342 is provided in the hydrofluoric acid supply line 340 to control the supply of hydrofluoric acid. A phosphoric acid supply source 351 is connected to the phosphoric acid supply line 350, and phosphoric acid is supplied from the phosphoric acid supply source 351 to tank 310 via the phosphoric acid supply line 350. A valve 352 is provided in the phosphoric acid supply line 350 to control the supply of phosphoric acid. A nitric acid supply source 361 is connected to the nitric acid supply line 360, and nitric acid is supplied from the nitric acid supply source 361 to tank 310 via the nitric acid supply line 360. A valve 362 is provided in the nitric acid supply line 360 ​​to control the supply of nitric acid. A water supply source 371 is connected to the water supply line 370, and water is supplied from the water supply source 371 to the tank 310 via the water supply line 370. A valve 372 is provided in the water supply line 370 to control the water supply.

[0049] Inside the tank 310, hydrofluoric acid, phosphoric acid, nitric acid, and water are supplied to the etching solution E in desired amounts, thereby adjusting the compositional concentration of the etching solution E. The compositional concentration of the etching solution E is the concentration of each component in the etching solution E. Furthermore, the concentration in this embodiment is expressed as a mass percentage concentration.

[0050] In this embodiment, the etching apparatus 40 includes a mechanism for supplying the etching solution E, such as a nozzle 220, a moving mechanism 221, a liquid supply line 222, etc., and the etching solution supply device 300, which correspond to the etching solution supply environment in this disclosure.

[0051] Next, a wafer processing method performed using the wafer processing system 1 configured as described above will be explained. In this embodiment, a wafer W cut from an ingot by a wire saw or the like, or a wrapped wafer W, is subjected to processing to obtain a desired thickness profile for the wafer W.

[0052] First, a hoop F containing multiple wafers W is placed on the hoop mounting table 10 of the loading / unloading station 2. In the hoop F, the wafers W are stored with their first surface Wa facing upwards and their second surface Wb facing downwards. Next, the wafer transport device 20 removes the wafers W from the hoop F and transports them to the transition device 30. The wafers W transported to the transition device 30 are then transported to the buffer device 72 by the wafer transport device 60.

[0053] Next, the wafer W is transported to the grinding device 90 by the wafer transport device 80 and transferred to the first chuck 93a at the first transfer position A1. At the first chuck 93a, the second surface Wb of the wafer W is held by suction.

[0054] Next, the rotary table 91 is rotated to move the wafer W to the first processing position B1. Then, the first grinding unit 100 grinds the first surface Wa of the wafer W (St1 in Figure 4).

[0055] Next, the rotary table 91 is rotated to move the wafer W to the first transfer position A1.

[0056] Next, the wafer W is transported to the cleaning device 70 by the wafer transport device 80. In the cleaning device 70, the first surface Wa of the wafer W is cleaned (St2 in Figure 4). In St2, the second surface Wb of the wafer W may also be cleaned.

[0057] Next, the wafer W is transported to the inversion device 73 by the wafer transport device 80. In the inversion device 73, the first surface Wa and the second surface Wb of the wafer W are inverted vertically (St3 in Figure 4). That is, the wafer W is inverted so that the first surface Wa faces downwards and the second surface Wb faces upwards.

[0058] Next, the wafer W is transported to the grinding device 90 by the wafer transport device 80 and transferred to the second chuck 93b at the second transfer position A2. At the second chuck 93b, the first surface Wa of the wafer W is held by suction.

[0059] Next, the rotary table 91 is rotated to move the wafer W to the second processing position B2. Then, the second grinding unit 110 grinds the second surface Wb of the wafer W (St4 in Figure 4).

[0060] Next, the rotary table 91 is rotated to move the wafer W to the second transfer position A2.

[0061] Next, the wafer W is transported to the cleaning device 70 by the wafer transport device 80. In the cleaning device 70, the second surface Wb of the wafer W is cleaned (St5 in Figure 4). In St5, the first surface Wa of the wafer W may also be cleaned.

[0062] Next, the wafer W is transported to the thickness measuring device 71 by the wafer transport device 80 or wafer transport device 60. The thickness measuring device 71 obtains the thickness distribution of the wafer W by measuring the thickness of the wafer W at multiple points after grinding the second surface Wb, and further calculates the thickness deviation of the wafer W (St6 in Figure 4). The obtained thickness distribution and thickness deviation of the wafer W are output to, for example, the control device 130.

[0063] The control device 130 determines the optimal etching conditions for the second surface Wb, optimizing the etching amount distribution (etching profile) in the etching process of the second surface Wb, based on the thickness distribution and thickness deviation of the wafer W acquired in St6 and output to the control device 130 (St7 in Figure 4). The etching amount is the amount of wafer W removed by etching, and the etching amount distribution is the distribution of etching amount in the radial direction (within the wafer surface) of the wafer W. In this embodiment, the optimal etching conditions for the second surface Wb correspond to the set etching conditions in this disclosure. The method for determining the optimal etching conditions for the second surface Wb in the control device 130 will be described later.

[0064] Next, the wafer W is transported to the etching apparatus 40 by the wafer transport device 60. In the etching apparatus 40, the second surface Wb of the wafer W is etched with the etching solution E under the optimal etching conditions determined in St7 (St8 in Figure 4). In St8, by etching the second surface Wb under the optimal etching conditions, the etching amount distribution is optimized and the second surface Wb is processed into the target shape.

[0065] In step S8, the etching solution E used for etching the second surface Wb is collected in the etching solution supply device 300 and reused. In the etching solution supply device 300, the used etching solution E flows into the tank 310. Inside the tank 310, hydrofluoric acid, phosphoric acid, nitric acid, and water are supplied to the etching solution E in desired amounts to adjust the composition concentration of the etching solution E. The etching solution E with the adjusted composition concentration is then supplied to the nozzle 220.

[0066] Next, the wafer W is transported to the inversion device 51 by the wafer transport device 60. In the inversion device 51, the first surface Wa and the second surface Wb of the wafer W are inverted vertically (St9 in Figure 4). That is, the wafer W is inverted so that the first surface Wa is facing upwards and the second surface Wb is facing downwards.

[0067] Next, the wafer W is transported to the thickness measuring device 50 by the wafer transport device 60. The thickness measuring device 50 obtains the thickness distribution of the wafer W by measuring the thickness of the wafer W at multiple points after etching the second surface Wb, and further calculates the thickness deviation of the wafer W (St10 in Figure 4). The obtained thickness distribution and thickness deviation of the wafer W are output to, for example, the control device 130.

[0068] The control device 130 determines the optimal etching conditions for the first surface Wa, optimizing the etching amount distribution during the etching process of the first surface Wa, based on the thickness distribution and thickness deviation of the wafer W acquired by St10 and output to the control device 130 (St11 in Figure 4). In this embodiment, the optimal etching conditions for the first surface Wa correspond to the set etching conditions in this disclosure. The method for determining the optimal etching conditions for the first surface Wa in the control device 130 will be described later.

[0069] Next, the wafer W is transported to the etching apparatus 40 by the wafer transport device 60. In the etching apparatus 40, the first surface Wa of the wafer W is etched with the etching solution E under the optimal etching conditions determined in St11 (St12 in Figure 4). In St12, the etching amount distribution is optimized by etching the first surface Wa under the optimal etching conditions, and the first surface Wa is processed into the target shape.

[0070] In S12, the etching solution E used for etching the first surface Wa is collected in the etching solution supply device 300 and reused. This reuse process is the same as the reuse process in St8 described above.

[0071] Next, the wafer W is transported to the thickness measuring device 50 by the wafer transport device 60. The thickness measuring device 50 obtains the thickness distribution of the wafer W by measuring the thickness of the wafer W at multiple points on both the first surface Wa and the second surface Wb after etching (St13 in Figure 4). The thickness measuring device 50 may also calculate the thickness deviation of the wafer W.

[0072] The thickness and thickness distribution of multiple wafers W obtained in St13 are output to the control device 130, for example, and used to determine the actual etching amount of wafer W and the state of the etching solution supply environment (St14 in Figure 4). Furthermore, the thickness and thickness distribution of these multiple wafers W may be used for processing other wafers W that are then processed by the wafer processing system 1.

[0073] Subsequently, the wafer W, having undergone all processing, is transported to the hoop F on the hoop mounting table 10 via the transition device 30. This completes the series of wafer processing steps in the wafer processing system 1.

[0074] In the above embodiment, the first surface Wa was ground with St1, and then the second surface Wb was ground with St4, but the order of grinding these surfaces may be reversed. Also, the second surface Wb was etched with St8, and then the first surface Wa was etched with St12, but the order of etching these surfaces may be reversed.

[0075] Next, the method for determining the optimal etching conditions (St7 and St11 in Figure 4) will be explained. This determination of the optimal etching conditions is performed by the control device 130. In the following explanation, the method for determining the optimal etching conditions for the first surface Wa at St11 will be described, but the method for determining the optimal etching conditions for the second surface Wb at St7 is the same.

[0076] First, before processing the wafer W in the wafer processing system 1, multiple training data are acquired (St100 in Figure 5). The training data is normal data acquired when etching is performed successfully, as will be described later, and includes the etching amount at multiple reference points on the wafer W and the etching amount distribution of the wafer W. The multiple reference points on the wafer W are reference points for acquiring the etching amount distribution of the wafer W. Furthermore, the multiple reference points on the wafer W are points that serve as references when determining the actual etching amount state of the wafer W and the state of the etching solution supply environment, as will be described later.

[0077] In St100, etching is performed on a dummy wafer using, for example, multiple different etching conditions (set etching conditions). Specifically, the dummy wafer is etched by changing, for example, the rotation speed R (also called rotational speed) of the dummy wafer during etching, the scan speed V (also called swing speed) of the nozzle 220, the scan width L (see scan width L in Figure 3, also called swing radius) of the nozzle 220, or the number of loops N of the nozzle 220. In this case, the etching processing time for each dummy wafer is the same. Etching of the dummy wafer is the same as etching the first surface Wa of the wafer W in St12. That is, the dummy wafer is rotated, and the etchant E is supplied from the nozzle 220 to the dummy wafer while the nozzle 220 is moved back and forth. In the following description, the back-and-forth movement of the nozzle 220 is considered one loop.

[0078] The etching of the dummy wafer under each etching condition is performed with the etching solution E's composition and concentration adjusted to a normal level, and with the etching solution supply environment in a normal state. In other words, each etching in the St100 learning process is performed under normal conditions, except for the different etching conditions. Furthermore, the etching of the dummy wafer under each etching condition is performed for a predetermined desired time (desired number of loops). And each etching is performed normally.

[0079] After etching a dummy wafer under each etching condition, the thickness of multiple reference points on the dummy wafer is measured, and the etching amount is derived. Hereinafter, the etching amount of multiple reference points may be referred to as the normal etching amount. The normal etching amount of multiple reference points is output to the control device 130 and stored in the control device 130 as the learning data. The etching conditions in this embodiment correspond to the set etching conditions in this disclosure.

[0080] Furthermore, after etching the dummy wafer under each etching condition, the etching amount distribution of the dummy wafer is obtained and output to the control device 130. The control device 130 then compresses the output etching amount distribution for each etching condition into an etching amount distribution per unit time (unit loop count), and stores each of these compressed etching amount distributions as the learning data.

[0081] In the above explanation, the case in which the learning data is obtained by etching a dummy wafer was used as an example, but the etching target when obtaining the learning data is not limited to a dummy wafer. Specifically, for example, the etching result of a product wafer W processed by the wafer processing system 1 may be stored as the learning data. Also, for example, if a film is formed on the first surface Wa of the wafer W, the etching target may be the film, and the etching result of the film may be stored as the learning data.

[0082] Furthermore, although the acquisition of the above-mentioned learning data was performed within the wafer processing system 1, it may also be performed outside the wafer processing system 1. In such a case, the control device 130 determines the optimal etching conditions based on a plurality of learning data acquired outside the wafer processing system 1.

[0083] Next, based on the thickness distribution of the target shape of the wafer W after etching and the thickness distribution of the surface shape of the wafer W after etching (hereinafter referred to as the "measured shape") obtained in St10, the target etching amount distribution in the etching process of St12 is obtained (St110 in Figure 5). The target etching amount distribution of the etching process can be obtained, for example, by calculating the difference between the thickness distribution of the target shape of the wafer W and the thickness distribution of the measured shape. The target shape of the wafer W can be, for example, a flat shape, a convex shape, a concave shape, a W-shape, an M-shape, or a combination of any two of these shapes.

[0084] Next, multiple training data (etching amount distributions) are superimposed, and an optimization method is used to optimize the training data used for superimposition and the number of times the training data is superimposed so that it matches the target etching amount distribution obtained in St110 (St111 in Figure 5).

[0085] In St111, for example, the control of the etching amount distribution is applied to the knapsack problem, and the number of times the training data is superimposed is optimized. For example, the etching amount distribution is the knapsack in the knapsack problem, and the training data is the items in the knapsack problem. Then, the number of times the training data is superimposed is optimized so that the difference between the superimposed etching amount distribution and the target etching amount distribution in St110 is minimized. In other words, the etching amount distribution when etching the first surface Wa in St12 is optimized.

[0086] Next, the etching conditions corresponding to the training data optimized in St111 are integrated to determine the optimal etching conditions (St112 in Figure 5). Specifically, the multiple etching conditions are integrated so that the selected multiple etching conditions are performed with an optimized number of superpositions, thereby determining the optimal etching conditions. In other words, the optimal etching conditions that optimize the etching amount distribution are determined.

[0087] As described above, the optimal etching conditions for the first surface Wa at St11 are determined. In this case, by etching the first surface Wa of the wafer W at St12 under the optimal etching conditions, the etching amount distribution can be optimized, and the first surface Wa can be processed into the target shape.

[0088] Next, the method for determining the etching amount of the wafer W and the state of the etching solution supply environment (St14 in Figure 4) will be explained. This determination of the etching amount of the wafer W and the state of the etching solution supply environment is performed by the control device 130.

[0089] First, before processing the wafer W in the wafer processing system 1, multiple abnormal data points are acquired (St200 in Figure 6). As will be described later, the abnormal data is acquired when etching is not performed normally, and includes the abnormal etching amount at multiple reference points on the wafer W, and the abnormal state relationship between the abnormal etching amount and the cause of the abnormality in the etching solution supply environment.

[0090] In St200, etching is performed on a wafer using, for example, multiple different etching conditions (set etching conditions). As described later, if the etching amount at multiple reference points on the wafer is determined to be abnormal, and the etching solution supply environment is determined to be abnormal, this etching amount is stored as the abnormal etching amount. The cause of the abnormal etching solution supply environment at this time is also investigated and stored. Then, the abnormal state relationship between these abnormal etching amounts and the cause of the abnormal etching solution supply environment is obtained and stored.

[0091] In addition, St200 may acquire abnormal etching data performed on wafers intended for products to be processed by the wafer processing system 1, or it may acquire abnormal etching data by performing etching on dummy wafers.

[0092] Next, the etching amount at multiple reference points is derived from the wafer W thickness measured at St13 (St201 in Figure 6). As mentioned above, the etching amount is the amount of wafer W removed by etching. In St201, the etching amount is calculated by subtracting the thickness of wafer W after etching of the first surface Wa, measured at St13, from the thickness of wafer W before etching of the first surface Wa, measured at St10. Hereafter, the etching amount derived at St201 may be referred to as the actual etching amount.

[0093] Next, for each reference point, the difference between the actual etching amount derived in St201 and the normal etching amount obtained in St100 is calculated, and this difference is compared with a pre-set threshold (St202 in Figure 6). In the comparison in St202, the normal etching amount is the normal etching amount under the etching conditions set in St12 (set etching conditions), that is, the same etching conditions as the optimal etching conditions determined in St11. Hereinafter, the difference calculated in St202 may be referred to as the etching amount difference.

[0094] The method for setting the threshold used in St202 is arbitrary. For example, the threshold may be set based on the abnormal etching amount obtained in St200. In this case, the threshold is the threshold corresponding to the boundary between normal and abnormal states of the etching solution supply environment. Alternatively, for example, if no abnormal data has been obtained in St200, the operator may set the threshold.

[0095] Furthermore, the threshold used in St202 may be set to the same value for multiple reference points, or different values ​​may be set for each reference point. For example, if different specifications are required for multiple reference points, thresholds may be set according to the specifications of each reference point.

[0096] Based on the comparison results in St202, the actual etching amount and the state of the etching solution supply environment are determined (St203 in Figure 6).

[0097] The inventors conducted thorough research and found that, under each etching condition, if the surface of wafer W was etched normally, similar to when acquiring the learning data for St100, the etching amount distribution of wafer W remained virtually unchanged over time. Figure 7 shows the etching amount distribution when wafer W was etched normally under three etching conditions A to C. Specifically, wafer W was etched a total of six times at one-month intervals under etching conditions A to C. Figures 7(a) to (c) show the etching amount distribution of these six times using different line types. Referring to Figure 7, under each etching condition A to C, if wafer W was etched normally, that is, if the etching solution supply environment was normal, the etching amount distribution remained virtually unchanged.

[0098] Therefore, St203 determines that the etching solution supply environment is normal if the actual etching amount at multiple reference points is normal. Specifically, for example, if the etching amount difference is below a threshold, the actual etching amount is determined to be normal, and furthermore, the etching solution supply environment is determined to be normal.

[0099] On the other hand, if the actual etching amount at multiple reference points is abnormal, it is determined that the etching solution supply environment is abnormal. Specifically, if the difference in etching amount is greater than the threshold, the actual etching amount is determined to be abnormal, and furthermore, the etching solution supply environment is determined to be abnormal.

[0100] If St203 determines that the actual etching amount and etching solution supply environment are normal, the control device 130 outputs this information to the display panel 120. The display panel 120 displays that the actual etching amount and etching solution supply environment are normal, i.e., the normal status is reported (St204 in Figure 6). Then, the etching process for the subsequent wafer W is continued.

[0101] On the other hand, if St203 determines that the actual etching amount and the etching solution supply environment are abnormal, it predicts the cause of the abnormality in the etching solution supply environment (St205 in Figure 6). In St205, the method for predicting the cause of the abnormality in the etching solution supply environment is arbitrary.

[0102] For example, based on the actual etching amount derived in St201, the cause of the abnormality in the etching solution supply environment is predicted from the abnormal state relationship between the abnormal etching amount obtained in St200 and the cause of the abnormality in the etching solution supply environment. Specifically, first, the distribution of the actual etching amount is obtained based on the actual etching amount at multiple reference points. Next, the trend of the radial distribution of the abnormal etching amount that matches the trend of the actual etching amount distribution is selected. Then, from the abnormal state relationship, the cause of the abnormality in the etching solution supply environment corresponding to the trend of the radial distribution of the abnormal etching amount is predicted.

[0103] For example, if no abnormal data is obtained at St200, the operator may predict the cause of the abnormality based on the actual etching amounts at multiple reference points.

[0104] Various causes can lead to abnormalities in the etching solution supply environment. Examples of such causes are listed below.

[0105] For example, an abnormality in the etching solution supply environment is an abnormality in the composition concentration of the etching solution E. Through diligent research by the inventors, it was found that, for example, the hydrofluoric acid concentration in the etching solution E affects the overall etching amount distribution, while the phosphoric acid concentration and nitric acid concentration affect the partial etching amount distribution.

[0106] Regarding hydrofluoric acid concentration, as shown in Figure 8, a higher hydrofluoric acid concentration results in a generally larger etching amount, while a lower hydrofluoric acid concentration results in a generally smaller etching amount. Figure 8 shows the etching amount distribution when the hydrofluoric acid concentration changes from A to C. For example, as shown in Figure 8(b), if the etching amount distribution is generally smaller than that of a normal hydrofluoric acid concentration B, as shown in Figure 8(a), we predict that hydrofluoric acid concentration A is smaller than normal. Also, for example, as shown in Figure 8(c), if the etching amount distribution is large, we predict that hydrofluoric acid concentration C is larger than normal. When the etching amount distribution is shifted in this way, we predict that the cause of the abnormality in the etching solution supply environment is the hydrofluoric acid concentration.

[0107] The phosphoric acid concentration affects the amount of etching, for example, in the center of the wafer W. The central area affected by the phosphoric acid concentration is the range from 0 mm from the center of the wafer W to a radius X1, for example, about 10 mm. For example, the etching amount may be normal in the outer peripheral area radially outside of radius X1, but the etching amount distribution may be abnormal in the central area within radius X1 from the center. In such cases, it is predicted that the cause of the abnormality in the etching solution supply environment is the phosphoric acid concentration.

[0108] Nitric acid concentration affects the amount of etching, for example, in the center of wafer W. The central area affected by nitric acid concentration is the range from 0 mm from the center of wafer W to a radius X2, for example, about 30 mm, which is greater than the radius X1. For example, the amount of etching may be normal in the outer peripheral area radially outside of radius X2, but the etching distribution may be abnormal in the central area within radius X2 from the center. In such cases, it is predicted that the cause of the abnormality in the etching solution supply environment is the nitric acid concentration.

[0109] As described above, if the composition concentration of etching solution E is abnormal, it will affect the etching amount distribution. Furthermore, if the actual etching amount distribution based on the actual etching amount derived in St201 is close to the etching amount distribution when the composition concentration of etching solution E is abnormal, then the cause of the abnormality in the etching solution supply environment is predicted to be an abnormality in the composition concentration of etching solution E.

[0110] For example, an abnormality in the etching solution supply environment is caused by an abnormality in the discharge conditions of the etching solution E from the nozzle 220. For example, if there is an abnormality in the pump 330 or valve 331 of the supply line 222, specifically, the pump 330 may deteriorate, reducing the capacity to deliver the etching solution E, or the valve 331 may deteriorate, making it impossible to discharge the specified amount of etching solution E. In such cases, an abnormality occurs in the amount of etching solution E supplied from the nozzle 220, affecting the etching amount distribution. Also, if there is an abnormality in the scanning of the nozzle 220 by the moving mechanism 221, an abnormality occurs in the diffusion distribution of the etching solution E supplied from the nozzle 220 to the wafer W, affecting the etching amount distribution. Therefore, if the actual etching amount distribution based on the actual etching amount derived in St201 is close to the etching amount distribution in the case of an abnormality in the discharge conditions of the etching solution E from the nozzle 220, the cause of the abnormality in the etching solution supply environment is predicted to be an abnormality in the discharge conditions of the etching solution E from the nozzle 220.

[0111] As described above, when an abnormality in the etching solution supply environment is predicted in St205, the abnormality is stored, and the etching amounts at the corresponding multiple reference points are stored as abnormal etching amounts. In other words, it is stored and accumulated as abnormal data (abnormal state relationship) in St200.

[0112] It should be noted that the causes of abnormalities in the etching solution supply environment are not limited to the examples above. For example, an operator may discover another cause of abnormality as a result of investigating the cause based on the actual etching amounts at multiple reference points. In such cases, that cause of abnormality will be stored in memory.

[0113] Next, the control device 130 outputs an abnormality in the etching solution supply environment and the cause of the abnormality to the etching solution supply environment to the display panel 120. The display panel 120 displays a warning that the actual etching amount and the etching solution supply environment are abnormal, and further displays the cause of the abnormality in the etching solution supply environment. In other words, these abnormalities and their causes are reported (St206 in Figure 6). Then, the etching process of the subsequent wafer W is stopped and the abnormality in the etching solution supply environment is repaired. Note that in St206, the display panel 120 may display one cause of abnormality or multiple causes.

[0114] Here, when performing the learning process to acquire learning data in St100, the composition concentration of the etching solution E is always constant at a normal concentration. However, in the production process of etching the wafer W, the composition concentration of the etching solution E may fluctuate. In such cases, the actual etching amount at multiple reference points will differ from the normal etching amount. Also, when performing the learning process to acquire learning data in St100, the discharge conditions of the etching solution E from the nozzle 220 are always normal. However, in the production process of etching the wafer W, the discharge conditions of the etching solution E from the nozzle 220 may be abnormal. In such cases, the actual etching amount at multiple reference points will also differ from the normal etching amount. However, conventionally, the state of the etching solution supply environment, including the composition concentration of the etching solution and the discharge conditions of the etching solution from the nozzle, has not been determined based on the state of the actual etching amount. Furthermore, it is difficult to accurately measure the composition concentration of the etching solution with a normal concentration meter. For this reason, it is difficult to detect abnormalities in the etching solution supply environment early, and equipment troubles cannot be resolved. As a result, it takes time to perform normal etching processing with the etching equipment.

[0115] In this respect, according to this embodiment, by deriving the actual etching amount at multiple reference points in St201, that is, by automatically monitoring the actual etching amount, the state of the actual etching amount and the state of the etching solution supply environment can be determined in St203. Specifically, the state of the compositional concentration of the etching solution E and the state of the discharge conditions of the etching solution E from the nozzle 220 can be determined. Therefore, the operator can constantly monitor the soundness of the etching apparatus 40.

[0116] Furthermore, the state determination in St203 is performed based on the comparison result between the etching amount difference in St202 and an acceptable threshold. That is, if the etching amount difference between the actual etching amount derived in St201 and the normal etching amount obtained in St100 is less than or equal to the threshold, the actual etching amount is determined to be normal, and the etching solution supply environment is also determined to be normal. On the other hand, if the etching amount difference is greater than the threshold, the actual etching amount is determined to be abnormal, and the etching solution supply environment is also determined to be abnormal. Therefore, the state determination in St203 can be performed appropriately.

[0117] Furthermore, the threshold values ​​used in St202 may be set differently for each of the multiple reference points. For example, if the etching accuracy required at the center of the wafer W is relatively high and the etching accuracy required at the outer edge of the wafer W is relatively low, the threshold value for the reference point at the center can be set relatively low, and the threshold value for the reference point at the outer edge can be set relatively high. By changing the threshold value for each reference point according to the required specifications in this way, the amount of etching on the wafer W can be appropriately controlled, and the etching of the wafer W can be performed efficiently.

[0118] Furthermore, if St203 determines that the actual etching amount is abnormal, and also determines that the etching solution supply environment is abnormal, the etching apparatus 40 can interrupt the subsequent processing of wafer W. In such a case, it becomes possible to prevent unnecessary product loss.

[0119] Furthermore, if the actual etching amount is determined to be abnormal in St203, and the etching solution supply environment is also determined to be abnormal, the cause of the abnormality in the etching solution supply environment is predicted in St205. In addition, in St206, a warning that the actual etching amount and the etching solution supply environment are abnormal is displayed on the display panel 120, and the cause of the abnormality in the etching solution supply environment is also displayed. As a result, the abnormality in the etching solution supply environment can be repaired early, and the stability of the etching process on the wafer W can be improved.

[0120] In the above embodiment, St202 used only one threshold value at each reference point, but two or more threshold values ​​may be set for each reference point. For example, the threshold values ​​for each reference point include a first threshold value and a second threshold value that is greater than the first threshold value.

[0121] In such cases, St203 determines that the actual etching amount is normal and the etching solution supply environment is normal if the difference in etching amount between the actual etching amount derived in St201 and the normal etching amount obtained in St100 is less than or equal to the first threshold. Then, it continues the etching process for the subsequent wafer W. If the etching amount difference is greater than the second threshold, it determines that the actual etching amount is abnormal and the etching solution supply environment is abnormal. Then, it stops the etching process for the subsequent wafer W and repairs the abnormality in the etching solution supply environment. If the etching amount difference is greater than the first threshold but less than or equal to the second threshold, it determines that the condition of the actual etching amount is deteriorating and that the condition of the etching solution supply environment is deteriorating.

[0122] If the condition of the etching solution supply environment is determined to be deteriorating as described above, the degree of deterioration may be further determined based on the actual etching amount. For example, if the actual etching amount is close to the normal etching amount, which is between the normal etching amount and the abnormal etching amount, the degree of deterioration of the etching solution supply environment is determined to be mild. Also, if the actual etching amount is close to the midpoint between the normal etching amount and the abnormal etching amount, the degree of deterioration of the etching solution supply environment is determined to be moderate. Furthermore, if the actual etching amount is close to the abnormal etching amount, the degree of deterioration of the etching solution supply environment is determined to be severe.

[0123] As described above, if it is determined that the etching solution supply environment is deteriorating, the display panel 120 in St206 will display a warning that the etching solution supply environment is deteriorating, and will also display the degree of deterioration. As a result, the operator can monitor the health of the etching apparatus 40 in more detail.

[0124] In St200 of the above embodiments, when acquiring multiple abnormal data, deterioration data may also be acquired. Deterioration data is data when the state of the etching solution supply environment is deteriorating as described above, and includes the progression of deterioration of the etching amount at multiple reference points on the wafer W and the deterioration state relationship between the deterioration factors of the etching solution supply environment.

[0125] In St200, etching is performed on a wafer under multiple different etching conditions (set etching conditions). If it is determined that the etching amount at multiple reference points on the wafer is deteriorating, and that the etching solution supply environment is deteriorating, the progression of this deterioration in etching amount is stored. The cause of the deterioration of the etching solution supply environment at this time is also investigated and stored. The relationship between the progression of this deterioration in etching amount and the cause of the deterioration in the etching solution supply environment is then obtained and stored.

[0126] Then, if St203 determines that the etching solution supply environment is deteriorating, the cause of the deterioration of the etching solution supply environment is predicted based on the deterioration state relationship obtained in St200, using the actual etching amount derived in St201. At this time, the timing when the cause of deterioration of the etching solution supply environment becomes abnormal is also predicted based on the actual etching amount.

[0127] As described above, when the timing of an abnormal etching solution supply environment is predicted, the display panel 120 in St206 displays this prediction of the abnormal etching solution supply environment timing. As a result, the operator can monitor the health of the etching apparatus 40 in more detail.

[0128] In the above embodiment, after etching the second surface Wb, the etching amount of the wafer W and the state of the etching solution supply environment were determined at St14 based on the thickness of the wafer W measured at St13. Alternatively, after etching the first surface Wa, the etching amount of the wafer W and the state of the etching solution supply environment may be determined based on the thickness of the wafer W measured at St10.

[0129] In the embodiments described above, etching of the second surface Wb at St8 was performed under the optimal etching conditions determined at St7, but it may be performed under predetermined etching conditions instead. In this case, St7 in this embodiment is omitted. Similarly, etching of the first surface Wa at St12 was performed under the optimal etching conditions determined at St11, but it may be performed under predetermined etching conditions instead. In this case, St11 in this embodiment is omitted.

[0130] The default etching conditions may be those set so that the surface of the wafer W after etching has the target shape. Alternatively, the default etching conditions may be those selected to correspond to the target shape of the wafer W surface after etching, for example, from the learning data acquired by St100.

[0131] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the constituent elements of the embodiments described above can be combined in any way. Such any combination will naturally yield the functions and effects of each constituent element in the combination, as well as other functions and effects that will be apparent to those skilled in the art from the description herein.

[0132] Furthermore, the effects described herein are merely descriptive or illustrative and not limiting. In other words, the technology relating to this disclosure may produce other effects that will be apparent to those skilled in the art from the description herein, in addition to or in lieu of the effects described herein.

[0133] 1 Wafer processing system 40 Etching apparatus 130 Control device E Etching solution W Wafer Wa First surface Wb Second surface

Claims

1. A substrate processing method for processing a substrate, comprising: supplying an etching solution containing at least one of hydrofluoric acid, phosphoric acid, and nitric acid to the surface of the substrate based on set etching conditions and etching the surface of the substrate; deriving the actual etching amount of a plurality of reference points on the surface of the substrate after etching; comparing the difference between the actual etching amount and a previously obtained normal etching amount and a preset threshold for each of the reference points; and determining the state of the actual etching amount and the state of the etching solution supply environment for supplying the etching solution to the surface of the substrate based on the result of the comparison, wherein the normal etching amount is the etching amount of the plurality of reference points obtained when the surface of the substrate is etched in advance under the set etching conditions and the etching is performed normally.

2. The substrate processing method according to claim 1, comprising: predicting the cause of the abnormality in the etching solution supply environment when the state of the etching solution supply environment is determined to be abnormal; and issuing a warning about the abnormality in the etching solution supply environment and the cause of the abnormality in the etching solution supply environment.

3. A substrate processing method according to claim 2, comprising: etching the surface of the substrate under the set etching conditions and, when the state of the etching solution supply environment is determined to be abnormal, obtaining in advance an abnormal state relationship between the abnormal etching amount and the cause of the abnormality in the etching solution supply environment during said etching; and, when the state of the etching solution supply environment is determined to be abnormal, predicting the cause of the abnormality in the etching solution supply environment based on the actual etching amount and the abnormal state relationship.

4. The substrate processing method according to claim 2, wherein the cause of the abnormality is an abnormality in the composition concentration of the etching solution.

5. The substrate processing method according to claim 2, wherein the cause of the abnormality is an abnormality in the discharge conditions of the etching solution from the nozzle.

6. The substrate processing method according to claim 1, comprising setting the threshold based on an abnormal etching amount obtained in advance, wherein the abnormal etching amount is the etching amount obtained at the plurality of reference points when the surface of the substrate is etched in advance under the set etching conditions and the state of the etching solution supply environment is determined to be abnormal.

7. The substrate processing method according to claim 1, wherein the threshold includes a first threshold and a second threshold greater than the first threshold, and the method includes determining that the state of the etching solution supply environment is normal when the difference is less than or equal to the first threshold, determining that the state of the etching solution supply environment is abnormal when the difference is greater than the second threshold, and determining that the state of the etching solution supply environment is deteriorating when the difference is greater than the first threshold and less than or equal to the second threshold.

8. The substrate processing method according to claim 7, further comprising determining the degree of deterioration of the etching solution supply environment based on the actual etching amount when it is determined that the condition of the etching solution supply environment is deteriorating.

9. A substrate processing method according to claim 7, comprising: obtaining in advance the progression of deterioration of the etching amount derived when the surface of the substrate is etched under the set etching conditions, and the deterioration relationship between the deterioration factors of the etching solution supply environment during said etching; and, if it is determined that the state of the etching solution supply environment is deteriorating, predicting the time when the state of the etching solution supply environment becomes abnormal based on the deterioration relationship and the actual etching amount.

10. The substrate processing method according to claim 1, further comprising setting the threshold for each reference point.

11. A substrate processing system for processing a substrate, comprising: an etching apparatus that supplies an etching solution containing at least one of hydrofluoric acid, phosphoric acid, and nitric acid to the surface of the substrate and etches the surface of the substrate; and a control device, wherein the control device performs the following actions: control of etching the surface of the substrate based on set etching conditions in the etching apparatus; control of deriving the actual etching amount of a plurality of reference points on the surface of the substrate after etching; control of comparing the difference between the actual etching amount and a previously acquired normal etching amount and a preset threshold for each of the reference points; and control of determining the state of the actual etching amount and the state of the etching solution supply environment for supplying the etching solution to the surface of the substrate based on the result of the comparison, wherein the normal etching amount is the etching amount of the plurality of reference points obtained when the surface of the substrate is etched in advance under the set etching conditions and the etching is performed normally.

12. The substrate processing system according to claim 11, wherein the control device, when it determines that the state of the etching solution supply environment is abnormal, performs the following actions: control to predict the cause of the abnormality in the etching solution supply environment; and control to issue a warning about the abnormality in the etching solution supply environment and the cause of the abnormality in the etching solution supply environment.

13. The substrate processing system according to claim 12, wherein the control device performs the following actions: an abnormal state relationship between an abnormal etching amount obtained when the surface of the substrate is etched under the set etching conditions and the state of the etching solution supply environment is determined to be abnormal, and the cause of the abnormality in the etching solution supply environment during the etching; and when the state of the etching solution supply environment is determined to be abnormal, an abnormal state relationship is obtained based on the actual etching amount to predict the cause of the abnormality in the etching solution supply environment from the abnormal state relationship.

14. The substrate processing system according to claim 12, wherein the cause of the abnormality is an abnormality in the composition concentration of the etching solution.

15. The substrate processing system according to claim 12, wherein the cause of the abnormality is an abnormality in the discharge conditions of the etching solution from the nozzle.

16. The substrate processing system according to claim 11, wherein the control device performs control to set the threshold value based on an abnormal etching amount acquired in advance, and the abnormal etching amount is the etching amount acquired at the plurality of reference points when the surface of the substrate is etched in advance under the set etching conditions and the state of the etching solution supply environment is determined to be abnormal.

17. The substrate processing system according to claim 11, wherein the threshold includes a first threshold and a second threshold greater than the first threshold, and the control device executes control to determine that the state of the etching solution supply environment is normal when the difference is less than or equal to the first threshold, determines that the state of the etching solution supply environment is abnormal when the difference is greater than the second threshold, and determines that the state of the etching solution supply environment is deteriorating when the difference is greater than the first threshold and less than or equal to the second threshold.

18. The substrate processing system according to claim 17, wherein the control device determines that the state of the etching solution supply environment is deteriorating, and performs control to determine the degree of deterioration of the etching solution supply environment based on the actual etching amount.

19. The substrate processing system according to claim 17, wherein the control device performs the following actions: control to acquire in advance the deterioration relationship between the progression of deterioration of the etching amount derived when the surface of the substrate is etched under the set etching conditions and the deterioration factors of the etching solution supply environment in said etching; and control to predict the time when the state of the etching solution supply environment becomes abnormal based on the deterioration relationship and the actual etching amount, when it is determined that the state of the etching solution supply environment is deteriorating.

20. The substrate processing system according to claim 11, wherein the control device performs control to set the threshold value for each reference point.

Images