Wet etching method

Abstract

The present invention provides a wet etching method, which suppresses scattering of cleaning water at the time of wet etching. A wafer (W) to be subjected to wet etching is supported by a wafer support member (3) having a gap. At the time of cleaning the upper surface of the wafer (W) supported by the wafer support member (3) by cleaning water, the cleaning water flowing down from the gap of the wafer support member (3) is recovered by a cleaning liquid bottle (32) disposed below the wafer support member (3). Thus, the cleaning water can be recovered favorably while suppressing scattering of the cleaning water to the surroundings of the wafer (W).

Description

TECHNICAL FIELD

[0001] The present application relates to a wet etching method. BACKGROUND

[0002] A wet etching is disclosed in Patent Literatures 1 to 3. In the wet etching, an etching liquid is supplied to an upper surface of a silicon wafer to etch the upper surface of the wafer.

[0003] Patent Literature 1: Japanese Patent Application Laid-Open No. 02-086130

[0004] Patent Literature 2: Japanese Patent Application Laid-Open No. 06-265869

[0005] Patent Literature 3: Japanese Patent Application Laid-Open No. 2017-028257

[0006] Conventionally, after etching, cleaning water for cleaning the wafer is scattered around the wafer. Therefore, in order to recover the scattered cleaning water, a large waste liquid treatment device is required. SUMMARY

[0007] An object of the present application is to provide a wet etching method in which scattering of cleaning water is suppressed at the time of wet etching.

[0008] The wet etching method of the present application (the present wet etching method) etches an upper surface of a wafer with an etching liquid, and includes: an etching step of etching the upper surface of the wafer by accumulating the etching liquid on the upper surface of the wafer by surface tension; a cleaning step of cleaning the upper surface of the wafer by cleaning water, and accumulating the cleaning water, which overflows from the upper surface of the wafer and falls, in a first bottle disposed below the wafer; and a drying step of drying the wafer by rotating the wafer with its center as a shaft.

[0009] The present wet etching method further includes an etching liquid recovery step of recovering the etching liquid from the upper surface of the wafer by using a suction unit, which is performed between the etching step and the cleaning step.

[0010] The present wet etching method further includes a mask removal step of removing a mask layer composed of a resin formed on the upper surface of the wafer, which is performed between the cleaning step and the drying step, and includes: a step of supplying an organic solvent to the upper surface of the wafer to dissolve the mask layer; and a step of accumulating the dissolved resin and the organic solvent, which drip from the wafer, in a second bottle disposed below the wafer.

[0011] In the present etching method, in the cleaning step, the cleaning water, which overflows from the upper surface of the wafer and falls, is accumulated in a cleaning liquid bottle disposed below the wafer.

[0012] Therefore, in the present embodiment, it is possible to recover the cleaning water favorably while suppressing scattering of the cleaning water to the periphery of the wafer.

[0013] Further, in the present etching method, in the etching step, the etching liquid is accumulated on the upper surface of the wafer by the surface tension, and thereby the etching is performed. Thus, it is possible to reduce the amount of the etching liquid used for the etching.

[0014] Further, in the present etching method, the etching liquid recovery step described above can be included. Thus, it is possible to suck the etching liquid from the upper surface of the wafer and recover it. Therefore, it is possible to suppress scattering of the etching liquid to the periphery of the wafer. Further, the recovered etching liquid has a possibility of a long etching time, but it is possible to reuse it. Therefore, it is possible to reduce the frequency of using a waste liquid treatment device for treating the etching liquid.

[0015] Further, in the present etching method, the mask removing step described above can be included. Thus, it is possible to remove the mask from the wafer easily.

[0016] Further, in the mask layer removing step, it is possible to accumulate the organic solvent and the dissolved resin that have dripped from the wafer in the second bottle. Therefore, it is possible to recover them easily while suppressing scattering of the organic solvent and the dissolved resin to the periphery of the wafer.

[0017] Further, in the past, the etching of the wafer has been performed in a manner that the etching liquid, the cleaning water, or the organic solvent is supplied to the wafer and the etching liquid, the cleaning water, and the organic solvent are scattered from the wafer. In this case, in order to accommodate the devices used for the etching step, the cleaning step, and the mask layer removing step, a large clean room of a size that enables an operator to perform work inside is used.

[0018] On the other hand, in the present embodiment, the liquid is supplied to the wafer and is sucked from the wafer to recover it, and the liquid that has overflowed from the wafer and fallen is recovered by the bottle. Therefore, it is possible to downsize the devices used for the etching step, the etching liquid recovery step, the cleaning step, and the mask layer removing step significantly. Therefore, it is possible to accommodate these devices in an accommodation room of a glove box type that is a small clean room. Thus, it is possible to eliminate the need for a large clean room, and it is possible to suppress the size and the cost of the devices for wet etching significantly. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is an explanatory view showing a preparation step of the etching method of the present embodiment.

[0020] Figure 2 is a perspective view showing a wafer support.

[0021] Figure 3 is a perspective view showing a wafer support on which a wafer is placed.

[0022] Figure 4 is an explanatory view showing an etching process.

[0023] Figure 5 is an explanatory view showing a structure of an etching solution bottle.

[0024] Figure 6 is an explanatory view showing an etching solution recovery process.

[0025] Figure 7 is an explanatory view showing a cleaning process.

[0026] Figure 8 is an explanatory view showing a first process of a mask layer removal process.

[0027] Figure 9 is an explanatory view showing a second process of a mask layer removal process.

[0028] Figure 10 is an explanatory view showing a drying unit used in a drying process.

[0029] Figure 11 is a perspective view showing a structure of the drying unit.

[0030] Explanation of Reference Signs

[0031] 3: wafer support; 4: main body portion; 5: base portion; 6: column portion; 8: leg; 22: etching solution bottle; 22a: opening; 23: etching solution supply portion; 24: etching solution supply nozzle; 25: etching solution supply nozzle lifting unit; 26: etching solution recovery portion; 27: etching solution recovery nozzle; 28: etching solution recovery nozzle lifting unit; 29: etching solution recovery bottle; 32: cleaning solution bottle; 32a: opening; 33: cleaning water supply portion; 34: cleaning water supply nozzle; 35: cleaning water supply nozzle lifting unit; 42: mask layer removal bottle; 42a: opening; 43: first liquid supply portion; 44: first liquid supply nozzle; 45: first liquid supply nozzle lifting unit; 46: second liquid supply portion; 47: second liquid supply nozzle; 48: second liquid supply nozzle lifting unit; 51: drying unit; 53: holding stage; 54: bottom surface portion; 55: support column pair; 56: holding surface; 57: rotating portion; 59: motor. DETAILED DESCRIPTION

[0032] The etching method of the present embodiment (present etching method) is an etching method of etching an upper surface of a wafer using an etching solution.

[0033] The wafer on which wet etching is performed in the present embodiment is, for example, a small diameter (for example, about 1 inch).

[0034] (1) Preparation Process

[0035] In the etching method, first, in a preparation process, as shown in Figure 1 The wafer W is placed on the wafer support 3 as shown by the arrow R. By this, the wafer W is supported by the wafer support 3.

[0036] Here, the structure of the wafer support 3 is explained. As shown in Figure 2 and Figure 3 The wafer support 3 has a main body portion 4 that supports the wafer W. The main body portion 4 includes a base portion 5 that places the wafer W, a plurality of column portions 6 that are erected on the base portion 5, and a ring portion 7 that is provided to connect the upper ends of the column portions 6.

[0037] The base portion 5 has a diameter slightly larger than the wafer W. The base portion 5 has a mesh shape that has a frame portion (bone portion) 5a and a hole portion 5b that is a gap of the frame portion 5a, and holds the wafer W in a state of partially contacting the lower surface of the wafer W. The column portions 6 are erected on the outer peripheral portion of the base portion 5 in a manner of surrounding the wafer W placed on the base portion 5.

[0038] In addition, the wafer support 3 has a plurality of legs 8 that extend outward from the main body portion 4. In the present embodiment, six legs 8 extend outward from the column portions 6 of the main body portion 4. The front end of each leg 8 has a stopper 9 that extends downward.

[0039] (2) Etching Process

[0040] The etching process is implemented after the preparation process. Among them, the etching process and the subsequent recovery process, cleaning process, mask removal process, and drying process are implemented, for example, in a small-sized housing chamber that is not shown. The housing chamber is, for example, a so-called glove box (a small-sized ventilation chamber) that is a closed container configured to be able to perform work in a state of being sealed from the outside air.

[0041] In the etching process, the upper surface of the wafer W is etched by accumulating the etching solution on the upper surface of the wafer W by surface tension. In the present embodiment, the upper surface of the wafer W supported by the wafer support 3 is etched by accumulating the etching solution on the upper surface of the wafer W.

[0042] As shown in Figure 4 In the etching unit process, the wafer support 3 that supports the wafer W is placed in the etching solution bottle 22. In addition, in the etching process, the etching solution supply portion 23 for supplying the etching solution is used.

[0043] As shown in Figure 4 and Figure 5As shown, the etching solution bottle 22 has an opening 22a at the top. The opening 22a is larger than the diameter of the wafer W and is formed in such a way that the wafer support 3 can be engaged by means of the legs 8. That is, in the etching process, as... Figure 5 As shown, the wafer support 3 that supports the wafer W is engaged by means of the leg 8 having the stop 9 at the opening 22a of the etching solution bottle 22.

[0044] like Figure 4 As shown, the etching solution supply unit 23 has an etching solution supply nozzle 24 for supplying etching solution and an etching solution supply nozzle lifting unit 25 for moving the etching solution supply nozzle 24 in the vertical direction. The etching solution supply nozzle 24 can be connected to the etching solution supply source ES.

[0045] In the etching process, the etching solution supply nozzle 24 is positioned at a predetermined height by the etching solution supply nozzle lifting unit 25 in the etching solution supply unit 23. Furthermore, the etching solution supply nozzle 24 is connected to the etching solution supply source ES, and a predetermined amount of etching solution is dripped from the etching solution supply nozzle 24 onto the upper surface of the wafer W supported by the wafer support member 3. As a result, the etching solution supply unit 23 forms an etching solution layer EL on the upper surface of the wafer W under the action of surface tension. Then, it remains idle for approximately 3 minutes from the formation of the etching solution layer EL. Thus, etching (chemical processing) is performed on the upper surface of the wafer W.

[0046] (3) Etching solution recovery process

[0047] The etching solution recovery process is performed between the etching process and the cleaning process (immediately following the etching process), and the etching solution is extracted from the upper surface of the wafer W to recover the etching solution.

[0048] In this embodiment, the etching solution recovery process is performed consecutively with the etching process. In this process, such as... Figure 6 As shown, an etching solution recovery unit 26 is used for recovering the etching solution. The etching solution recovery unit 26 is an example of an aspiration unit.

[0049] That is, in the etching solution recovery process, with the wafer support 3 mounted on the etching solution bottle 22 and an etching solution layer EL formed on the wafer W supported by the wafer support 3, a replacement is placed on the etching solution bottle 22. Figure 4 The etching solution supply unit 23 shown is equipped with an etching solution recovery unit 26.

[0050] like Figure 6 As shown, the etching solution recovery unit 26 has an etching solution recovery nozzle 27 for recovering etching solution and an etching solution recovery nozzle lifting unit 28 for moving the etching solution recovery nozzle 27 in the vertical direction. Furthermore, the etching solution recovery unit 26 has an etching solution recovery bottle 29 connected to the etching solution recovery nozzle 27 and an etching solution suction pump EV connected to the etching solution recovery bottle 29.

[0051] In the etching solution recovery process, the etching solution recovery nozzle 27 is positioned at a height that contacts the etching solution layer EL formed on the upper surface of the wafer W using the etching solution recovery nozzle lifting unit 28 of the etching solution recovery unit 26. Furthermore, the etching solution suction pump EV is driven to depressurize the etching solution recovery bottle 29. As a result, the etching solution recovery nozzle 27, which communicates with the etching solution recovery bottle 29, draws the etching solution forming the etching solution layer EL from the upper surface of the wafer W. The etching solution drawn up by the etching solution recovery nozzle 27 is accumulated in the etching solution recovery bottle 29 and recovered.

[0052] Etching solution that is not completely recovered by the etching solution recovery section 26 overflows from the upper surface of the wafer W and flows through the gaps in the wafer support 3, as shown by arrow A, into the etching solution bottle 22 for accumulation and recovery. The gaps in the wafer support 3 include, for example, the spaces between multiple pillars 6 and the holes 5b in the base 5 (see reference). Figure 2 ).

[0053] Additionally, the etching solution is, for example, a mixture of acetic acid, nitric acid, and phosphoric acid. Furthermore, the volume of the etching solution forming the etching layer EL is, for example, 0.3 mL. The recovered etching solution is also in approximately the same volume.

[0054] (4) Cleaning process

[0055] In the cleaning process, the upper surface of the wafer W, which has absorbed the etching solution, is cleaned with cleaning water, and the cleaning water that overflows and falls from the upper surface of the wafer W is collected in the first bottle located below the wafer W.

[0056] In the cleaning process of this embodiment, such as Figure 7 As shown, the wafer W supported on the wafer support 3 is cleaned with cleaning water. In the cleaning process, a cleaning solution bottle 32 for placing the wafer support 3 and a cleaning water supply unit 33 for supplying cleaning water are used.

[0057] The cleaning solution bottle 32 has the same structure as the etching solution bottle 22. That is, as... Figure 5 and Figure 7 As shown, the cleaning solution bottle 32 has an opening 32a at the top. The opening 32a is larger than the diameter of the wafer W and is formed in such a way that the wafer support 3 can be engaged by means of the leg 8. That is, in the cleaning process, as... Figure 5 As shown, the opening 32a of the cleaning solution bottle 32 engages with the wafer support 3 that supports the wafer W via a leg 8 having a stop 9. The cleaning solution bottle 32 is an example of the first bottle.

[0058] like Figure 7As shown, the cleaning water supply section 33 has a cleaning water supply nozzle 34 for supplying cleaning water and a cleaning water supply nozzle elevating unit 35 for moving the cleaning water supply nozzle 34 in the up-and-down direction. The cleaning water supply nozzle 34 is communicable with the cleaning water supply source WS.

[0059] In the cleaning process, the cleaning water supply nozzle 34 is disposed at a prescribed height by the cleaning water supply nozzle elevating unit 35 of the cleaning water supply section 33. Also, the cleaning water supply nozzle 34 is in communication with the cleaning water supply source, and cleaning water is supplied (e.g., pulsed) from the cleaning water supply nozzle 34 to the upper surface of the wafer W supported by the wafer support 3. Thereby, the upper surface of the wafer W is cleaned by the cleaning water.

[0060] The cleaning water used in the cleaning overflows from the upper surface of the wafer W, flows into the cleaning liquid bottle 32 via the gap of the wafer support 3, as shown by the arrow B, and is accumulated and recovered. In this way, the cleaning water that flows down from the gap of the wafer support 3 is recovered.

[0061] (5) Mask removal process

[0062] The mask removal process is implemented between the cleaning process and the drying process. In the mask removal process, a mask layer (not shown) composed of resin formed on the upper surface of the wafer W is removed. The mask removal process includes: supplying an organic solvent to the upper surface of the wafer W to dissolve the mask layer; and accumulating the dissolved resin and the organic solvent that drips from the wafer W in the 2nd bottle disposed below the wafer W.

[0063] In the mask removal process of the present embodiment, as shown in Figure 8 the mask layer of the wafer W supported by the wafer support 3 is removed.

[0064] In addition, the mask layer removal process includes: a 1st process using a 1st liquid as the organic solvent; and a 2nd process using a 2nd liquid (mask removal liquid) as another organic solvent.

[0065] In the 1st process of the mask layer removal process, as shown in Figure 8 the mask layer removal bottle 42 for placing the wafer support 3 and a 1st liquid supply section 43 for supplying the 1st liquid are used.

[0066] The mask layer removal bottle 42 has the same structure as the etching liquid bottle 22. That is, as shown in Figure 5 and Figure 8 the mask layer removal bottle 42 has an opening 42a in the upper portion. The opening 42a is larger than the diameter of the wafer W and is formed in a manner that the wafer support 3 can be engaged by the leg 8. That is, in the mask layer removal process, as shown in Figure 5As shown, the opening 42a of the mask layer removal bottle 42 engages with the wafer support 3 that supports the wafer W by means of a leg 8 having a stop 9. The mask layer removal bottle 42 is an example of the second bottle.

[0067] like Figure 8 As shown, the first liquid supply unit 43 has a first liquid supply nozzle 44 for supplying the first liquid and a first liquid supply nozzle lifting unit 45 for moving the first liquid supply nozzle 44 in a vertical direction. The first liquid supply nozzle 44 can communicate with the first liquid supply source S1. The first liquid is an alcohol-based liquid, such as ethanol or isopropanol.

[0068] In the first step of the mask layer removal process, the first liquid supply nozzle 44 is positioned at a predetermined height by the first liquid supply nozzle lifting unit 45. Furthermore, the first liquid supply nozzle 44 is connected to the first liquid supply source S1, and the first liquid is supplied from the first liquid supply nozzle 44 to the upper surface of the wafer W supported by the wafer support member 3. As a result, the moisture on the upper surface of the wafer W is replaced by the alcohol-based first liquid.

[0069] The first liquid supplied to the upper surface of wafer W overflows from the upper surface of wafer W and flows through the gap of wafer support 3, as shown by arrow C, into the mask layer removal bottle 42 for accumulation and recovery.

[0070] The second step of the mask layer removal process continues from the first step and is performed on the wafer W supported by the wafer support 3 on the mask layer removal bottle 42. In the second step, a second liquid supply unit 46 for supplying the second liquid is used.

[0071] like Figure 9 As shown, the second liquid supply unit 46 has a second liquid supply nozzle 47 for supplying a second liquid and a second liquid supply nozzle lifting unit 48 for moving the second liquid supply nozzle 47 in a vertical direction. The second liquid supply nozzle 47 can communicate with the second liquid supply source S2. The second liquid is, for example, acetone.

[0072] In the second step of the mask layer removal process, the second liquid supply nozzle 47 is positioned at a predetermined height by the second liquid supply nozzle lifting unit 48 of the second liquid supply unit 46. Furthermore, the second liquid supply nozzle 47 is connected to the second liquid supply source S2, and the second liquid is supplied from the second liquid supply nozzle 47 to the upper surface of the wafer W supported by the wafer support member 3. This dissolves the resin-based mask layer, removing it from the mask layer.

[0073] The second liquid and the dissolved resin supplied to the upper surface of the wafer W overflow from the upper surface of the wafer W and flow through the gap of the wafer support 3, as shown by arrow C, into the mask layer removal bottle 42 for accumulation and recycling.

[0074] In this way, during the mask layer removal process, the first liquid, the second liquid, and the dissolved resin flowing down from the gap of the wafer support 3 are recovered.

[0075] (6) Drying process

[0076] The drying process involves rotating the wafer W around its center axis to dry it. The drying process in this embodiment is as follows: Figure 10 As shown, the drying unit 51 is used to dry the wafer W supported by the wafer support 3. Figure 10 and Figure 11 As shown, the drying unit 51 has a holding stage 53 for holding the wafer support 3 and a rotating part 57 for rotating the holding stage 53 within the container 52.

[0077] The holding stage 53 holds the wafer support 3 that supports the wafer W, and attracts and holds the lower surface of the wafer W. The rotating part 57 rotates the holding stage 53 to dry the wafer W.

[0078] The holding table 53 has: an annular bottom surface 54; a plurality of support columns 55 erected on the bottom surface 54; and a holding surface 56 fixed to the center of the bottom surface 54.

[0079] The bottom portion 54 has a diameter larger than the base 5 of the wafer support 3. A pair of support pillars 55, each formed by two support pillars 55a, is erected on the outer periphery of the bottom portion 54. The pair of support pillars 55 is configured to hold the legs 8 of the wafer support 3 between the two support pillars 55a. Therefore, in this embodiment, six pairs of support pillars 55 are erected on the bottom portion 54 in a manner corresponding to the six legs 8 of the wafer support 3.

[0080] The holding surface 56 contains a porous ceramic material and is in communication with an attraction source (not shown), thereby adsorbing and holding the wafer W placed on the base 5 of the wafer support 3 across the base 5.

[0081] The rotating part 57 has a motor 59 inside the housing 58. The main shaft 59a of the motor 59 is connected to the lower surface of the holding surface 56 in the holding stage 53. In addition, the wafer W is held on the holding surface 56, for example, with the rotation axis of the motor 59 (the center of the main shaft 59a) passing through the center of the wafer W.

[0082] In the holding stage 53, the holding stage 53, which holds the wafer support 3, is rotated integrally (at a speed of, for example, 7500 rpm) by the motor 59 of the rotating part 57. As a result, the wafer W, supported by the wafer support 3 and attracted and held by the holding surface 56 of the holding stage 53, rotates, for example, about the center of the wafer W. As a result, the liquid remaining on the upper surface of the wafer W (for example, the first liquid and the second liquid) vaporizes, thereby drying the upper surface of the wafer W.

[0083] In the present embodiment, in the cleaning process, the cleaning water that has overflowed from the upper surface of the wafer W and fallen down is accumulated in the cleaning liquid bottle 32 disposed below the wafer W. Therefore, in the present embodiment, the cleaning water can be recovered while suppressing scattering of the cleaning water to the surroundings of the wafer W.

[0084] In the present embodiment, in the etching process, an etching liquid layer is formed on the upper surface of the wafer W by surface tension. That is, a prescribed amount of etching liquid is dripped to the upper surface of the wafer W supported by the wafer support 3, and an etching liquid layer is formed by surface tension. Thereby, the amount of etching liquid used for etching can be reduced.

[0085] In the present embodiment, in the etching liquid recovery process, the etching liquid is sucked from the upper surface of the wafer W by the etching liquid recovery section 26. Thereby, scattering of the etching liquid to the surroundings of the wafer W can be suppressed. Further, the recovered etching liquid has a possibility of having a long etching time, but can be reused. Therefore, the frequency of using a waste liquid treatment device for treating the etching liquid can be reduced.

[0086] In the present embodiment, in the cleaning process, the cleaning water is supplied to the upper surface of the wafer W supported by the wafer support 3 engaged with the opening 32a of the cleaning liquid bottle 32.

[0087] In this way, by engaging the leg 8 of the wafer support 3 with the opening 32a of the cleaning liquid bottle 32, the wafer W can be disposed at the center of the opening 32a of the cleaning liquid bottle 32. That is, the wafer W can be disposed at the center of the opening 32a in a manner of being suspended in the air.

[0088] Therefore, in the cleaning process, the cleaning liquid that has overflowed from the wafer W and flowed down from the gap of the wafer support 3 can be easily recovered by the cleaning liquid bottle 32.

[0089] In the present embodiment, in the drying process, a holding stage 53 that holds the wafer support 3 and attracts and holds the lower surface of the wafer W, and a rotating section 57 that rotates the holding stage 53 to dry the wafer W are used. Thereby, the wafer W can be easily dried. In particular, in the present embodiment, the support column pair 55 of the holding stage 53 sandwiches the leg 8 of the wafer support 3. Therefore, the wafer W can be easily suppressed from falling from the holding stage 53 due to the influence of centrifugal force at the time of rotation.

[0090] In addition, in the present embodiment, in the mask layer removal process, the first liquid, the second liquid, and the dissolved resin that have dripped from the wafer W are accumulated in the mask layer removal bottle 42 via the gap of the wafer support 3 and are recovered. Thus, the first liquid, the second liquid, and the dissolved resin can be recovered easily while preventing the first liquid, the second liquid, and the dissolved resin from scattering around the wafer W.

[0091] In addition, in the past, etching of a wafer has been performed in such a manner that an etching liquid, cleaning water, a first liquid, or a second liquid is supplied to the wafer and the etching liquid, the cleaning water, the first liquid, and the second liquid are scattered from the wafer. In this case, in order to accommodate devices used in an etching process, a cleaning process, and a mask layer removal process, a large clean room capable of allowing an operator to perform work inside is used.

[0092] On the other hand, in the present embodiment, a liquid is supplied to the wafer W and the liquid on the wafer W is sucked and recovered, and a bottle is used to recover a liquid that has overflowed from the wafer W and has flowed down from the gap of the wafer support 3. Thus, the devices used in the etching process, the etching liquid recovery process, the cleaning process, and the mask layer removal process can be significantly downsized. Thus, these devices can be accommodated in an accommodation room of a glove box type that is a small ventilation room. Thus, it is not necessary to use a large clean room, and the size and cost of the devices used for wet etching can be significantly reduced.

[0093] In addition, by using an accommodation room of a glove box type, it is possible to prevent an operator from inhaling the etching liquid that has vaporized and dust that has adhered to the wafer W after drying, as in the case of using a clean room.

[0094] In addition, in the present embodiment, in the etching liquid recovery process, the etching liquid bottle 22 is used. In this regard, in a case where it is possible to recover substantially all of the etching liquid by the etching liquid recovery section 26, it is not necessary to use the etching liquid bottle 22.

[0095] In addition, in the present embodiment, in the etching liquid recovery process, the etching liquid recovery section 26 sucks the etching liquid. Alternatively, the used etching liquid can be recovered by the etching liquid bottle 22. In this case, it is not necessary to provide the etching liquid recovery section 26.

[0096] In addition, in the present embodiment, the etching liquid bottle 22 and the cleaning liquid bottle 32 are used. Alternatively, these bottles can be shared. For example, the etching is performed while the wafer support 3 that supports the wafer W is engaged with the cleaning liquid bottle 32, and after the etching liquid is recovered by the etching liquid recovery section 26, the upper surface of the wafer W is cleaned by the cleaning water supply section 33. In this case, the cleaning water flows into the cleaning liquid bottle 32 and is accumulated and recovered. In this configuration, it is possible to omit the etching liquid bottle 22, and thus it is possible to downsize and reduce the cost of the devices.

Claims

1. A wet etching method of etching an upper surface of a wafer with an etching liquid, wherein the wet etching method comprises: a preparation step of placing the wafer on a wafer support having a main body portion that supports the wafer and has a gap, and a plurality of legs that extend outward from the main body portion; an etching step of etching the upper surface of the wafer with the etching liquid accumulated on the upper surface of the wafer by surface tension; a cleaning step of cleaning the upper surface of the wafer with cleaning water while the wafer support that supports the wafer is engaged with an opening of a stationary first bottle disposed below the wafer by the legs, and the wafer is disposed in the center of the opening in a manner of floating in the air, and the cleaning water that has overflowed from the upper surface of the wafer and fallen through the gap of the main body portion is accumulated in the first bottle; and a drying step of drying the wafer by rotating the wafer with its center as an axis.

2. The wet etching method according to claim 1, wherein the wet etching method further comprises an etching liquid recovery step of sucking the etching liquid from the upper surface of the wafer with a sucking unit, which is performed between the etching step and the cleaning step.

3. The wet etching method according to claim 1, wherein the wet etching method further comprises a mask removal step of removing a mask layer composed of a resin formed on the upper surface of the wafer, which is performed between the cleaning step and the drying step, the mask removal step comprises: providing an organic solvent to the upper surface of the wafer to dissolve the mask layer; and accumulating the dissolved resin and the organic solvent that have dripped from the wafer in a second bottle disposed below the wafer. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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