Substrate processing method and substrate processing device

Abstract

The present invention provides a substrate processing method and a substrate processing apparatus. The substrate processing method of an embodiment includes a forming step and a processing step. In the forming step, an alkaline treatment solution with a reduced oxygen concentration is supplied to the substrate, thereby forming a liquid film of the alkaline treatment solution on the substrate. In the processing step, after a liquid film of a predetermined thickness is formed on the substrate, the alkaline treatment solution is supplied and the substrate is rotated to etch the substrate. The present invention can improve the uniformity of the etching amount in the depth direction of the hole formed in the substrate.

Description

Technical Field

[0001] The present invention relates to a substrate processing method and a substrate processing device. Background Art

[0002] Patent Document 1 discloses a technique in which an alkaline treatment solution containing dissolved oxygen is supplied to a substrate to perform an etching process.

[0003] Prior art literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2019-12802 Summary of the Invention

[0005] Technical problem to be solved by the invention

[0006] The present invention provides a technique for improving the uniformity of the etching amount in the depth direction of a hole formed in a substrate.

[0007] Technical solutions to technical problems

[0008] A substrate processing method according to one embodiment of the present invention includes a forming step and a treating step. In the forming step, an alkaline treating solution with a reduced oxygen concentration is supplied to the substrate to form a liquid film of the alkaline treating solution on the substrate. In the treating step, with the liquid film of a predetermined thickness formed on the substrate, the alkaline treating solution is supplied and the substrate is rotated to etch the substrate.

[0009] Effects of the Invention

[0010] According to the present invention, the uniformity of the etching amount in the depth direction of the hole formed in the substrate can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a diagram showing a schematic configuration of a substrate processing system according to the first embodiment.

[0012] Figure 2 It is a schematic diagram showing the configuration of the processing unit and the mixing unit according to the first embodiment.

[0013] Figure 3 It is a schematic diagram showing a specific configuration example of the processing unit according to the first embodiment.

[0014] Figure 4 This is a flowchart illustrating the etching liquid generation process according to the first embodiment.

[0015] Figure 5 This is a flowchart illustrating substrate processing according to the first embodiment.

[0016] Figure 6A This is a schematic diagram of a hole in a wafer during substrate processing in a comparative example.

[0017] Figure 6B This is a schematic diagram of a hole in a wafer during substrate processing according to the first embodiment.

[0018] Figure 7 This is a simulation result of the substrate processing in the first embodiment.

[0019] Figure 8 This is a diagram showing the relationship between the wafer rotation speed and the etching amount in substrate processing according to the first embodiment.

[0020] Figure 9 It is a schematic diagram showing the structure of a processing unit according to the second embodiment.

[0021] Figure 10 It is a schematic diagram showing the structure of a processing unit according to the third embodiment.

[0022] Figure 11 It is a schematic diagram showing the structure of a processing unit according to the fourth embodiment.

[0023] Description of Reference Numerals

[0024] 1. Substrate processing system

[0025] 3 Processing Stations

[0026] 4 Control device

[0027] 16 Processing Unit (Processing Unit)

[0028] 18 Control Department

[0029] 70 Dissolution

[0030] 71. Liquid storage container

[0031] 75 Bubble pipe

[0032] 78 Inert gas supply source

[0033] 100 Release Department

[0034] 106 Inert gas supply source

[0035] 120 dike and dam mechanism

[0036] 121 Dike Department. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the substrate processing method and substrate processing apparatus disclosed in the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the substrate processing method and substrate processing apparatus disclosed in the embodiments shown below.

[0038] (First embodiment)

[0039] <Overview of Substrate Processing System>

[0040] First, refer to Figure 1 , a schematic structure of the substrate processing system 1 according to the first embodiment will be described. Figure 1 1 is a diagram showing a schematic configuration of a substrate processing system 1 according to the first embodiment. Hereinafter, to clarify positional relationships, mutually orthogonal X-axis, Y-axis, and Z-axis are defined, with the positive direction of the Z-axis being the vertically upward direction.

[0041] like Figure 1 As shown, the substrate processing system 1 includes a loading and unloading station 2 and a processing station 3 (an example of a substrate processing apparatus). The loading and unloading station 2 and the processing station 3 are arranged adjacent to each other.

[0042] The loading and unloading station 2 includes a carrier placement unit 11 and a conveying unit 12. The carrier placement unit 11 holds a plurality of carriers C for storing a plurality of substrates (semiconductor wafers W (hereinafter referred to as wafers W) in this embodiment) in a horizontal state.

[0043] The transport unit 12 is disposed adjacent to the carrier placement unit 11 and includes a substrate transport device 13 and an interface 14 therein. The substrate transport device 13 includes a wafer holding mechanism for holding a wafer W. The substrate transport device 13 is movable in the horizontal and vertical directions and rotatable about a vertical axis, and uses the wafer holding mechanism to transport wafers W between the carrier C and the interface 14.

[0044] The processing station 3 is provided adjacent to the conveyor 12. The processing station 3 includes a conveyor 15 and a plurality of processing units 16 (an example of a processing unit). The plurality of processing units 16 are provided side by side on both sides of the conveyor 15.

[0045] The transport unit 15 is internally provided with a substrate transport device 17. The substrate transport device 17 includes a wafer holding mechanism for holding the wafer W. The substrate transport device 17 is movable in the horizontal and vertical directions and rotatable about a vertical axis, and uses the wafer holding mechanism to transport the wafer W between the interface 14 and the processing unit 16.

[0046] The processing unit 16 performs a predetermined substrate process on the wafer W transported by the substrate transport device 17. The processing unit 16 is connected to a dissolving unit 70 that dissolves an inert gas in an alkaline aqueous solution L (an example of an alkaline treatment solution) and supplies the dissolved inert gas to the processing unit 16. Examples of the configurations of the processing unit 16 and the dissolving unit 70 will be described later.

[0047] Furthermore, the substrate processing system 1 includes a control device 4. The control device 4 is, for example, a computer, and includes a control unit 18 and a storage unit 19.

[0048] The storage unit 19 stores programs for controlling various processes executed in the substrate processing system 1. The storage unit 19 is implemented by a semiconductor memory element such as RAM (Random Access Memory) or flash memory, or a storage device such as a hard disk or optical disk.

[0049] The control unit 18 controls the operation of the substrate processing system 1 by reading and executing a program stored in the storage unit 19. Alternatively, the program may be stored in a computer-readable storage medium and installed from the storage medium into the storage unit 19 of the control device 4. Examples of computer-readable storage media include a hard disk (HD), a floppy disk (FD), a compact disk (CD), a magneto-optical disk (MO), and a memory card.

[0050] In the substrate processing system 1 configured as described above, the substrate transport device 13 of the transport station 2 first removes a wafer W from the carrier C placed on the carrier placement portion 11 and places the removed wafer W on the delivery portion 14. The substrate transport device 17 of the processing station 3 removes the wafer W placed on the delivery portion 14 and transports it to the processing unit 16.

[0051] After the wafer W is fed into the processing unit 16 and processed by the processing unit 16, it is transferred out of the processing unit 16 by the substrate transfer device 17 and placed on the delivery unit 14. The processed wafer W placed on the delivery unit 14 is then returned to the carrier C of the carrier placement unit 11 by the substrate transfer device 13.

[0052] <Processing Unit and Mixing Section>

[0053] Next, refer to Figure 2 , explaining the processing unit 16 and the dissolving part 70. Figure 2 Schematic diagram showing the structure of the processing unit 16 and the dissolving unit 70 of the first embodiment. Figure 2 As shown, the processing unit 16 includes a chamber 20 , a substrate holding mechanism 30 , a processing fluid supply 40 , and a recovery cup 50 .

[0054] The chamber 20 houses a substrate holding mechanism 30, a processing fluid supply unit 40, and a recovery cup 50. A fan filter unit (FFU) 21 is provided at the top of the chamber 20. The FFU 21 creates a downflow in the chamber 20.

[0055] The substrate holding mechanism 30 includes a holding portion 31, a support portion 32, and a drive portion 33. The holding portion 31 horizontally holds the wafer W. The support portion 32 is a member extending in the vertical direction. Its base end is rotatably supported by the drive portion 33, and its tip end horizontally supports the holding portion 31. The drive portion 33 rotates the support portion 32 about a vertical axis.

[0056] The substrate holding mechanism 30 rotates the support portion 32 using the driving portion 33 to rotate the holding portion 31 supported by the support portion 32 , thereby rotating the wafer W held by the holding portion 31 .

[0057] The processing fluid supply unit 40 supplies the processing fluid to the wafer W. Furthermore, the processing fluid supply unit 40 is connected to the dissolving unit 70 .

[0058] The recovery cup 50 is arranged to surround the holding portion 31 and collects the processing liquid scattered from the wafer W due to the rotation of the holding portion 31. A drain port 51 is formed at the bottom of the recovery cup 50. The processing liquid collected by the recovery cup 50 is discharged from the drain port 51 to the outside of the processing unit 16. In addition, an exhaust port 52 is formed at the bottom of the recovery cup 50 for exhausting the gas supplied from the FFU 21 to the outside of the processing unit 16.

[0059] The dissolving unit 70 includes a drug solution storage container 71 , a circulation line 72 , a pump 73 , a temperature regulator 74 , and a bubbling line 75 .

[0060] The chemical storage container 71 stores an alkaline aqueous solution (an example of an alkaline treatment solution) L used as an etching solution. The alkaline aqueous solution L contains, for example, at least one of TMAH (TetraMethylAmmonium Hydroxide), a choline aqueous solution, a KOH (potassium hydroxide) aqueous solution, and ammonia water.

[0061] The chemical solution storage container 71 is connected to a circulation line 72 for circulating the stored alkaline aqueous solution L. The circulation line 72 is connected to the aforementioned treatment fluid supply unit 40 .

[0062] A pump 73 and a temperature regulator 74 are provided in the circulation line 72. The pump 73 circulates the alkaline aqueous solution L, which has been adjusted to a predetermined temperature by the temperature regulator 74, through the circulation line 72. The predetermined temperature is a preset temperature, for example, approximately 25°C. Alternatively, the predetermined temperature may be higher than 25°C, or may be approximately 80°C.

[0063] Furthermore, a sensor 79 for measuring the oxygen concentration in the alkaline aqueous solution L is provided in the circulation line 72 .

[0064] Furthermore, a bubbling line 75 for adding an inert gas to the stored alkaline aqueous solution L to cause bubbling is connected to the chemical solution storage container 71. The inert gas is, for example, nitrogen.

[0065] The bubbling line 75 is provided with a valve 76 and a flow rate regulator 77 . The bubbling line 75 supplies inert gas from an inert gas supply source 78 to the chemical solution storage container 71 via the valve 76 and the flow rate regulator 77 .

[0066] The inert gas supplied from the bubbling line 75 dissolves in the alkaline aqueous solution L. That is, the dissolving unit 70 dissolves the inert gas in the alkaline aqueous solution L. The oxygen concentration of the alkaline aqueous solution L decreases due to the dissolution of the inert gas.

[0067] Below, refer to Figure 3 , describing a specific structural example of the processing unit 16. Figure 3 It is a schematic diagram showing a specific configuration example of the processing unit 16 according to the first embodiment.

[0068] like Figure 3 As shown, a holding member 311 for holding the wafer W from the side is provided on the upper surface of the holding portion 31 of the substrate holding mechanism 30. The wafer W is held horizontally by the holding member 311 in a state slightly away from the upper surface of the holding portion 31. The wafer W is held in the holding portion 31 with the surface to be etched facing upward.

[0069] The processing fluid supply unit 40 includes a plurality of (here, four) nozzles 41 a to 41 d , an arm 42 that horizontally supports the nozzles 41 a to 41 d , and a rotation and lifting mechanism 43 that rotates and lifts the arm 42 .

[0070] The nozzle 41a is connected to the dissolving unit 70 via a valve 44a and a flow regulator 45a. The nozzle 41b is connected to a DIW supply source 46b via a valve 44b and a flow regulator 45b. DIW (Deionized Water) is used, for example, for rinsing.

[0071] Nozzle 41c is connected to a DHF supply source 46c via valve 44c and flow regulator 45c. DHF (diluted hydrofluoric acid) is used, for example, for oxide film removal. Nozzle 41d is connected to an IPA supply source 46d via valve 44d and flow regulator 45d. IPA (isopropyl alcohol) is used, for example, for drying.

[0072] The nozzle 41a discharges the alkaline aqueous solution L supplied from the dissolving unit 70. The nozzle 41b discharges DIW supplied from the DIW supply source 46b. The nozzle 41c discharges DHF supplied from the DHF supply source 46c. The nozzle 41d discharges IPA supplied from the IPA supply source 46d.

[0073] The processing unit 16 (an example of a processing unit) supplies an alkaline aqueous solution L containing an inert gas (alkaline treatment solution) to a wafer W (an example of a substrate) to perform an etching process on the wafer W. Specifically, the processing unit 16 supplies the alkaline aqueous solution L containing an inert gas to the wafer W while rotating the wafer W while forming a liquid film of the alkaline aqueous solution L containing an inert gas to a predetermined thickness. The etching process will be described in detail later.

[0074] <Substrate Processing>

[0075] Below, refer to Figure 4 The etching solution generation process of the first embodiment is described with reference to the flowchart of FIG. Figure 4 This is a flowchart illustrating the etching liquid generation process according to the first embodiment.

[0076] The control device 4 performs a temperature adjustment process (S100). The control device 4 drives the pump 73 to circulate the alkaline aqueous solution L in the circulation line 72. The control device 4 also adjusts the temperature of the alkaline aqueous solution L to a predetermined temperature using the temperature regulator 74.

[0077] The control device 4 performs a dissolution treatment (S101). The control device 4 supplies an inert gas to the alkaline aqueous solution L (an example of an alkaline treatment solution). Specifically, the control device 4 supplies an inert gas to the alkaline aqueous solution L in the drug solution storage container 71 from the bubbling line 75, dissolving the inert gas in the alkaline aqueous solution L and reducing the oxygen concentration of the alkaline aqueous solution L. The control device 4 uses a sensor 79 to measure the oxygen concentration of the alkaline aqueous solution L circulating in the circulation line 72, and supplies an inert gas from the bubbling line 75 so that the oxygen concentration of the alkaline aqueous solution L becomes below a specified concentration. The specified concentration is a pre-set concentration, specifically 0.1 ppm. That is, the oxygen concentration of the alkaline aqueous solution L is below 0.1 ppm.

[0078] In addition, the temperature adjustment process and the dissolution process may be performed as one process. In addition, the temperature adjustment process and the dissolution process may be included in the substrate process described below.

[0079] Below, refer to Figure 5 The flowchart of the first embodiment illustrates the substrate processing. Figure 5 This is a flowchart illustrating substrate processing according to the first embodiment.

[0080] The control device 4 performs a loading process (S200). The control device 4 uses the substrate transport device 17 to load the wafer W into the chamber 20 of the processing unit 16. The wafer W is held in the holding member 311 with the surface to be etched facing upward. The control device 4 then controls the drive unit 33 to rotate the substrate holding mechanism 30. In other words, the control device 4 rotates the wafer W.

[0081] The control device 4 performs oxide film removal processing (S201). The control device 4 moves the nozzle 41c of the processing fluid supply unit 40 to above the center of the wafer W. The control device 4 supplies DHF as an etching solution to the surface of the wafer W from the nozzle 41c.

[0082] The DHF supplied to the surface of the wafer W is diffused over the entire surface of the wafer W by the centrifugal force caused by the rotation of the wafer W. Thus, the natural oxide film formed on the wafer W is removed by the DHF.

[0083] The control device 4 performs a first rinse process (S202). The control device 4 moves the nozzle 41b of the treatment fluid supply unit 40 to the center of the wafer W. The control device 4 causes the nozzle 41b to supply DIW to the surface of the wafer W. The DIW supplied to the surface of the wafer W replaces the DHF remaining on the surface of the wafer W.

[0084] The control device 4 performs etching processing ( S203 ). The control device 4 supplies the alkaline aqueous solution L in which the oxygen concentration on the surface of the wafer W is reduced to the wafer W, and etches the wafer W with the alkaline aqueous solution L.

[0085] The control device 4 first diffuses the alkaline aqueous solution L onto the entire surface of the wafer W, forming a liquid film of the alkaline aqueous solution L on the surface of the wafer W. Specifically, the control device 4 moves the nozzle 41a of the processing fluid supply unit 40 to the center of the wafer W. Then, the control device 4 supplies the alkaline aqueous solution L to the surface of the wafer W from the nozzle 41a at a first prescribed flow rate, and rotates the wafer W at a first prescribed speed. The first prescribed flow rate is a pre-set flow rate, for example, 1.5 L / min. The first prescribed speed is a pre-set speed, for example, a speed set to 500 rpm or more. The first prescribed speed in this embodiment is, for example, 1000 rpm.

[0086] The alkaline aqueous solution L supplied to the surface of the wafer W is diffused over the entire surface of the wafer W due to the centrifugal force associated with the rotation of the wafer W. The time for rotating the wafer W at the first predetermined rotation speed only needs to be sufficient for the alkaline aqueous solution L to diffuse over the entire surface of the wafer W, and may be a short time such as 2 seconds.

[0087] The control device 4 then etches the wafer W while maintaining the thickness of the alkaline aqueous solution L formed on the surface of the wafer W at a predetermined thickness or greater. Specifically, the control device 4 rotates the wafer W at a second predetermined rotational speed. The predetermined thickness is a predetermined thickness, for example, 400 μm or greater. The second predetermined rotational speed is a predetermined rotational speed that is lower than the first predetermined rotational speed. The second predetermined rotational speed is set, for example, to a speed lower than 500 rpm. In this embodiment, the second predetermined rotational speed is set, for example, to be greater than 0 rpm and less than 30 rpm.

[0088] The control device 4 supplies the alkaline aqueous solution L from the nozzle 41 a and rotates the wafer W to etch the wafer W while a liquid film of the alkaline aqueous solution L having a predetermined thickness or greater is formed.

[0089] The control device 4 performs a second rinsing process (S204). The control device 4 supplies DIW to the surface of the wafer W in the same manner as in the first rinsing process.

[0090] By supplying DIW to the surface of the wafer W, the alkaline aqueous solution L remaining on the surface of the wafer W is replaced with DIW.

[0091] The control device 4 performs a drying process (S205). The control device 4 moves the nozzle 41d of the processing fluid supply unit 40 to the upper center of the wafer W. The control device 4 rotates the substrate holding mechanism 30 at a predetermined rotational speed and supplies IPA from the nozzle 41d to the surface of the wafer W. After supplying IPA for a predetermined time, the control device 4 stops supplying IPA and spin-dries the wafer W.

[0092] By supplying IPA to the surface of the wafer W, the DIW remaining on the surface of the wafer W is replaced with IPA. Alternatively, the control device 4 may spin-dry the wafer W without supplying IPA.

[0093] The control device 4 performs a discharge process (S206). The control device 4 controls the drive unit 33 to stop the rotation of the wafer W, and then controls the substrate transport device 17 to discharge the wafer W from the processing unit 16. When the discharge process is completed, a series of substrate processes for one wafer W is completed.

[0094] It is known that when an etching process is performed using the alkaline aqueous solution L, oxygen contained in the alkaline aqueous solution L is adsorbed on the wafer W, and an oxide film F is formed.

[0095] Here, a comparative example is described in which the substrate processing of the first embodiment is not performed. In the substrate processing of this comparative example, the oxygen concentration in the alkaline aqueous solution L is not reduced, and the thickness of the liquid film of the alkaline aqueous solution L is not maintained above the specified thickness. Furthermore, in the chamber 20, a downflow is formed by the FFU 21, and oxygen dissolves from the surface of the liquid film of the alkaline aqueous solution L, resulting in a high oxygen concentration near the surface of the liquid film of the alkaline aqueous solution L.

[0096] Therefore, in the substrate processing of the comparative example, oxygen adsorption increases near the opening of the hole H of the wafer W, as shown in FIG. Figure 6A As shown, the formed oxide film F becomes thicker. Figure 6A Schematic diagram of a hole H in a wafer W during substrate processing in a comparative example.

[0097] Furthermore, in the substrate processing of the comparative example, oxygen is adsorbed near the opening of the hole H in the wafer W, resulting in a lower oxygen concentration in the alkaline aqueous solution L on the bottom side of the hole H in the wafer W than near the opening. Consequently, the thickness of the oxide film F formed on the bottom side of the hole H in the wafer W becomes thinner than on the opening side, increasing the difference between the etching amount on the opening side of the hole H in the wafer W and the etching amount on the bottom side of the hole H in the wafer W. Consequently, in the substrate processing of the comparative example, the etching ratio, which is obtained by dividing the etching amount at the bottom of the hole H by the etching amount at the opening of the hole H, becomes larger.

[0098] In contrast, in the substrate processing of the first embodiment, etching is performed using the alkaline aqueous solution L in which the inert gas is dissolved to reduce the oxygen concentration. Therefore, in the substrate processing of the first embodiment, oxygen adsorption near the opening of the hole H of the wafer W can be suppressed.

[0099] Furthermore, etching is performed by supplying the alkaline aqueous solution L while rotating the wafer W, while maintaining the thickness of the alkaline aqueous solution L film formed on the surface of the wafer W at a predetermined thickness or greater. Thus, in the substrate processing of the first embodiment, when oxygen dissolves from the surface of the alkaline aqueous solution L film, the distance between the oxygen near the surface of the alkaline aqueous solution L film and the opening of the hole H on the wafer W becomes longer. Therefore, in the substrate processing of the first embodiment, oxygen adsorption near the opening of the hole H on the wafer W can be suppressed.

[0100] In the substrate processing of the first embodiment, as Figure 6B As shown, the formation of the oxide film F near the opening of the hole H in the wafer W can be suppressed. Therefore, in the substrate processing of the first embodiment, the difference between the etching amount on the opening side of the hole H in the wafer W and the etching amount on the bottom side of the hole H in the wafer W is reduced. Therefore, in the substrate processing of the first embodiment, the etching ratio is reduced. Figure 6B Schematic diagram of the hole H of the wafer W during substrate processing according to the first embodiment.

[0101] in addition, Figure 7 The simulation results of the oxygen concentration and etching ratio at the opening of the hole H in the wafer W are shown. Figure 7 This is the simulation result of the substrate processing in the first embodiment. Figure 7 In FIG, nitrogen as an active gas is dissolved in the alkaline aqueous solution L, and the etching ratio is shown when the oxygen concentration of the alkaline aqueous solution L is changed. Figure 7 In the simulation shown, the rotation speed of the wafer W is 30 rpm.

[0102] like Figure 7 As shown in FIG. 1 , when the oxygen concentration at the opening of hole H in wafer W decreases, the etching ratio approaches 1. When the oxygen concentration in alkaline aqueous solution L is 0.1 ppm or less, the etching ratio is low, and the uniformity of the etching amount at the bottom side of hole H and at the opening side of hole H can be improved. In other words, the uniformity of the etching amount in the depth direction of hole H in wafer W can be improved.

[0103] In the substrate processing of the first embodiment, after the alkaline aqueous solution L is diffused over the entire surface of the wafer W, the substrate rotation speed is set to 30 rpm to perform etching processing.

[0104] Here, Figure 8 The relationship between the rotation speed of the wafer W and the etching amount is shown. Figure 8 : is a graph showing the relationship between the rotation speed of the wafer W and the etching amount in the substrate processing of the first embodiment. Figure 8 , the etching amounts when the rotation speed of the wafer W is set to 1000 rpm, 500 rpm, and 200 rpm are shown.

[0105] like Figure 8 As shown in FIG. 1 , when the rotation speed of the wafer W is reduced, the difference in etching amount corresponding to the distance from the center of the wafer W can be reduced. In other words, when the rotation speed of the wafer W is reduced, the uniformity of etching amount in the radial direction of the wafer W, i.e., in-plane uniformity, can be improved.

[0106] As described above, the substrate processing method of the first embodiment includes a forming step and a treating step. In the forming step, an alkaline aqueous solution L (an example of an alkaline treatment solution) with a reduced oxygen concentration is supplied to a wafer W (an example of a substrate), thereby forming a liquid film of the alkaline aqueous solution L on the wafer W. In the treating step, after a liquid film of a predetermined thickness (predetermined thickness) is formed on the wafer W, the alkaline aqueous solution L is supplied and the wafer W is rotated to etch the wafer W. Specifically, the oxygen concentration of the alkaline aqueous solution L is 0.1 ppm or less.

[0107] This can suppress the formation of the oxide film F near the opening of the hole H in the wafer W. Therefore, the difference in the etching amount in the depth direction of the hole H in the wafer W can be reduced, and the uniformity of the etching amount in the depth direction of the hole H can be improved.

[0108] In the forming step, the wafer W is rotated at a first rotational speed. In the processing step, the wafer W is rotated at a second rotational speed that is lower than the first rotational speed.

[0109] Thus, a liquid film of the alkaline aqueous solution L is quickly formed across the entire wafer W, and the infiltration of oxygen into the hole H can be suppressed. Furthermore, a liquid film of the alkaline aqueous solution L having a predetermined thickness or greater can be formed on the wafer W, and the formation of an oxide film F near the opening of the hole H in the wafer W can be suppressed. Consequently, the difference in the amount of etching in the depth direction of the hole H in the wafer W can be reduced, and the uniformity of the amount of etching in the depth direction of the hole H can be improved. Furthermore, by setting the rotational speed of the wafer W to the second rotational speed, ripples in the liquid surface of the alkaline aqueous solution L can be suppressed, and the incorporation of oxygen into the alkaline aqueous solution L can be suppressed.

[0110] The substrate processing method further includes a dissolving step in which an inert gas is dissolved in the alkaline aqueous solution L.

[0111] This can reduce the oxygen concentration of the alkaline aqueous solution L supplied to the wafer W. Therefore, the difference in the etching amount in the depth direction of the hole H in the wafer W can be reduced, and the uniformity of the etching amount in the depth direction of the hole H can be improved.

[0112] The substrate processing method further includes a replacement step in which the alkaline aqueous solution L of the etched wafer W is replaced with DIW (an example of a rinse solution). This completes the etching process of the wafer W.

[0113] The processing station 3 (an example of a substrate processing apparatus) includes a dissolving unit 70 and a processing unit 16 (an example of a processing unit). The dissolving unit 70 mixes an inert gas into an alkaline aqueous solution L (an example of an alkaline treatment solution).

[0114] Thus, the processing unit 16 can suppress the formation of the oxide film F near the opening of the hole H in the wafer W. Therefore, the processing unit 16 can reduce the difference in the etching amount in the depth direction of the hole H in the wafer W and improve the uniformity of the etching amount in the depth direction of the hole H.

[0115] (Second embodiment)

[0116] Next, a substrate processing system 1 according to a second embodiment will be described. Here, differences from the substrate processing system 1 according to the first embodiment will be described. Components identical to those of the substrate processing system 1 according to the first embodiment are denoted by the same reference numerals as those of the substrate processing system 1 according to the first embodiment, and detailed descriptions thereof will be omitted.

[0117] <Processing Unit>

[0118] The processing unit 16 of the second embodiment is as follows: Figure 9As shown, a release portion 100 for releasing an inert gas toward a wafer W (an example of a substrate) is provided. Figure 9 Schematic diagram showing the structure of the processing unit 16 according to the second embodiment. The inert gas is nitrogen.

[0119] The release unit 100 includes a nozzle 101, an arm 102 that supports the nozzle 101, and a rotation mechanism 103 that rotates the arm 102. The rotation mechanism 103 can also move the arm 102 up and down.

[0120] The nozzle 101 is connected to an inert gas supply source 106 via a valve 104 and a flow regulator 105. The nozzle 101 releases inert gas toward the wafer W. In addition, the inert gas supply source 106 can be connected to the bubble line 75 (see Figure 2 ) An inert gas supply source 78 (refer to Figure 2 That is, the inert gas supplied to the alkaline aqueous solution L and the inert gas released from the nozzle 101 to the wafer W can be supplied from the same inert gas supply source.

[0121] <Substrate Processing>

[0122] Next, the substrate processing of the second embodiment is described. Figure 5 The substrate processing is the same as that of the first embodiment shown.

[0123] The control device 4 is in the etching process ( Figure 5 In step S203), while the alkaline aqueous solution L is diffused over the entire surface of the wafer W, the inert gas is released from the release portion 100 and the alkaline aqueous solution L is supplied. For example, after the control device 4 releases the inert gas from the release portion 100 onto the surface of the wafer W, the alkaline aqueous solution L is supplied from the nozzle 41 a so that the alkaline aqueous solution L is diffused over the entire surface of the wafer W.

[0124] By releasing the inert gas from the release portion 100 toward the wafer W, an inert gas layer is formed on the surface of the wafer W. Therefore, the amount of oxygen dissolved in the liquid film of the alkaline aqueous solution L formed on the surface of the wafer W can be reduced.

[0125] Furthermore, the release of the inert gas from the release section 100 onto the surface of the wafer W may also be performed throughout the etching process. The control device 4 also releases the inert gas from the release section 100 onto the wafer W when the alkaline aqueous solution L is supplied from the nozzle 41 a to the surface of the wafer W at a first predetermined flow rate. The control device 4 supplies the inert gas onto the wafer W (an example of a substrate) at least before a liquid film of the alkaline aqueous solution L is formed on the wafer W.

[0126] The substrate processing method according to the second embodiment includes a gas supply step of supplying an inert gas to a wafer W (an example of a substrate) at least before the forming step.

[0127] This can suppress the dissolution of oxygen in the liquid film of the alkaline aqueous solution L formed on the surface of the wafer W, and can suppress the formation of the oxide film F near the opening of the hole H in the wafer W. Therefore, the difference in the etching amount in the depth direction of the hole H in the wafer W can be reduced, and the uniformity of the etching amount in the depth direction of the hole H can be improved.

[0128] (Third embodiment)

[0129] Next, a substrate processing system 1 according to a third embodiment will be described. Here, differences from the substrate processing system 1 according to the first embodiment will be described. Components identical to those of the substrate processing system 1 according to the first embodiment are denoted by the same reference numerals as those of the substrate processing system 1 according to the first embodiment, and detailed descriptions thereof will be omitted.

[0130] <Processing Unit>

[0131] The processing unit 16 of the third embodiment is as follows: Figure 10 As shown, a nozzle 41 a that discharges the alkaline aqueous solution L is supported by an arm 110 . Figure 10 It is a schematic diagram showing the structure of the processing unit 16 according to the third embodiment.

[0132] The arm 110 is rotated and raised and lowered by the rotating and raising and lowering mechanism 111. That is, in the processing unit 16, the nozzle 41b for discharging DIW, the nozzle 41c for discharging DHF, and the nozzle 41a for discharging the alkaline aqueous solution L are supported by different arms 42 and 110.

[0133] <Substrate Processing>

[0134] Next, the etching process of the third embodiment will be described. Figure 5 The substrate processing is the same as that of the first embodiment shown.

[0135] The control device 4 is in the etching process Figure 5 , S203), the nozzle 41a is arranged above the outer periphery of the wafer W, and the alkaline aqueous solution L is supplied to the outer periphery of the wafer W, thereby etching the outer periphery of the wafer W with the alkaline aqueous solution L. In addition, the control device 4 arranges the nozzle 41b above the center of the wafer W and supplies DIW to the center of the wafer W.

[0136] Specifically, the control device 4 supplies DIW to the center of the wafer W and supplies the alkaline aqueous solution L to the outer periphery of the wafer W. Furthermore, the control device 4 rotates the wafer W at a second predetermined rotational speed to supply DIW and the alkaline aqueous solution L to the wafer W. As described above, the second predetermined rotational speed is set to a speed lower than 500 rpm, for example, 200 rpm or less. Furthermore, the control device 4 supplies DIW and the alkaline aqueous solution L for a predetermined time. The predetermined time is a pre-set time, for example, 120 seconds.

[0137] Thereafter, the control device 4 stops supplying the alkaline aqueous solution L and continues supplying DIW, thereby replacing the alkaline aqueous solution L on the outer periphery of the wafer W with DIW.

[0138] When replacement with DIW is completed, the control device 4 stops supplying DIW and positions the nozzle 41a at the center of the wafer W. The control device 4 then supplies the alkaline aqueous solution L from the nozzle 41a onto the surface of the wafer W, replacing the DIW with the alkaline aqueous solution L and spreading the alkaline aqueous solution L over the entire surface of the wafer W. Specifically, the processing unit 16 (an example of a processing unit) supplies the alkaline aqueous solution L (an example of an alkaline treatment solution) to the outer periphery of the wafer W (an example of a substrate), and after stopping the supply of the alkaline aqueous solution L to the outer periphery, supplies the alkaline aqueous solution L to the center of the wafer W.

[0139] Then, similarly to the first embodiment, the control device 4 supplies the alkaline aqueous solution L from the nozzle 41a to the surface of the wafer W at a first predetermined flow rate and rotates the wafer W at a second predetermined rotational speed. Similar to the first embodiment, the second predetermined rotational speed is set to, for example, a rotational speed less than 500 rpm. For example, the second predetermined rotational speed is set to be greater than 0 rpm and less than 30 rpm.

[0140] In the formation step of the substrate processing method of the third embodiment, an alkaline aqueous solution L (an example of an alkaline treatment solution) is supplied to the outer periphery of a wafer W (an example of a substrate). After the supply of the alkaline aqueous solution L to the outer periphery is stopped, the alkaline aqueous solution L is supplied to the center of the wafer W. Thus, the outer periphery of the wafer W is pre-etched before the alkaline aqueous solution L is supplied to the center of the wafer W. Therefore, when etching is performed by supplying the alkaline aqueous solution L to the center of the wafer W, the in-plane uniformity of the wafer W can be improved.

[0141] (Fourth embodiment)

[0142] Next, a substrate processing system 1 according to a fourth embodiment will be described. Here, differences from the substrate processing system 1 according to the first embodiment will be described. Components identical to those of the substrate processing system 1 according to the first embodiment are denoted by the same reference numerals as those of the substrate processing system 1 according to the first embodiment, and detailed descriptions thereof will be omitted.

[0143] <Processing Unit>

[0144] The processing unit 16 of the fourth embodiment is as follows Figure 11 A weir mechanism 120 is shown. Figure 11 Schematic diagram showing the structure of the processing unit 16 according to the fourth embodiment. The weir mechanism 120 includes a weir portion 121 , a support portion 122 , a support column 123 , and a moving mechanism 124 .

[0145] The dam portion 121 is formed in a cylindrical shape. The dam portion 121 is arranged inside the recovery cup 50. In addition, the dam portion 121 is arranged on the outer periphery of the holding portion 31. That is, the dam portion 121 surrounds the outer periphery of the chip W held by the holding portion 31. The dam portion 121 suppresses the alkaline aqueous solution L supplied to the chip W from flowing out of the chip W. In other words, the dam portion 121 blocks the alkaline aqueous solution L from flowing out of the chip W. In addition, in order to prevent the dam portion 121 from interfering with the holding portion 31, a gap is formed between the dam portion 121 and the holding portion 31.

[0146] The support portion 122 supports the weir portion 121. The support portion 122 includes a first support member 122a extending in the horizontal direction and a second support member 122b extending in the vertical direction and connecting the weir portion 121 and the first support member 122a.

[0147] The support portion 123 extends in the vertical direction and is connected to the first support member 122a. The support portion 123 supports the support portion 122 and the dam portion 121. The support portion 123 is formed in a cylindrical shape, and the support portion 32 of the substrate holding mechanism 30 can be inserted therein.

[0148] The moving mechanism 124 moves the support portion 123 in the vertical direction. Specifically, the moving mechanism 124 moves the support portion 122 and the dam portion 121 in the vertical direction via the support portion 123. Specifically, the moving mechanism 124 moves the dam portion 121 between a clearance position and a blocking position. The clearance position is where the upper end surface of the dam portion 121 is lower than the upper surface of the wafer W. Furthermore, the blocking position is where the upper end surface of the dam portion 121 is higher than the upper surface of the wafer W. For example, the blocking position is where the upper end surface of the dam portion 121 is higher than the upper surface of the wafer W by a predetermined thickness or more.

[0149] Regarding the weir mechanism 120 , during etching processing, the weir portion 121 becomes a blocking position, and the alkaline aqueous solution L is blocked on the wafer W by the weir portion 121 .

[0150] As described above, the processing unit 16 (an example of a processing portion) supplies an alkaline aqueous solution L (an example of an alkaline treatment liquid) containing an inert gas to the chip W (an example of a substrate) in a state where the outer periphery of the chip W is surrounded by the dam portion 121.

[0151] <Substrate Processing>

[0152] Next, the substrate processing of the fourth embodiment will be described. The entire process of the substrate processing of the fourth embodiment is the same as that of the substrate processing of the first embodiment.

[0153] The control device 4 is in the etching process ( Figure 5 , S203), the dam portion 121 of the dam mechanism 120 moves from the avoidance position to the blocking position, and the alkaline aqueous solution L is supplied to the chip W.

[0154] The alkaline aqueous solution L is blocked by the weir portion 121, forming a liquid film having a predetermined thickness or greater on the surface of the wafer W. Furthermore, although a portion of the alkaline aqueous solution L leaks downward from the gap formed between the weir portion 121 and the holding portion 31, the flow rate of the alkaline aqueous solution L supplied from the nozzle 41a is greater than the flow rate of the alkaline aqueous solution L leaking from the gap. Therefore, a liquid film having a predetermined thickness or greater is formed on the surface of the wafer W.

[0155] The control device 4 supplies the alkaline aqueous solution L from the nozzle 41a at a first predetermined flow rate and rotates the wafer W at a second predetermined rotation speed. The control device 4 also supplies the alkaline aqueous solution L from the nozzle 41a while rotating the arm 42 supporting the nozzle 41a.

[0156] As described above, by supplying the alkaline aqueous solution L, the thickness of the liquid film formed by the alkaline aqueous solution L on the wafer W is maintained at a predetermined thickness or greater, thereby performing the etching process. The alkaline aqueous solution L is blocked by the dam portion 121 and supplied from the nozzle 41 a, so that it overflows from the dam portion 121.

[0157] In the processing step of the substrate processing method of the fourth embodiment, the alkaline aqueous solution L (an example of an alkaline treatment solution) is supplied while the outer periphery of the wafer W (an example of a substrate) is surrounded by the dam portion 121 .

[0158] Thus, the thickness of the liquid film of the alkaline aqueous solution L can be maintained at a predetermined thickness or greater by the dam portion 121, and the oxygen-containing alkaline aqueous solution L present near the liquid surface of the liquid film of the alkaline aqueous solution L can be allowed to overflow from the dam portion 121. Therefore, the formation of the oxide film F near the opening of the hole H in the wafer W can be suppressed, and the difference in the etching amount in the depth direction of the hole H in the wafer W can be reduced, thereby improving the uniformity of the etching amount in the depth direction of the hole H.

[0159] (Variation)

[0160] In the substrate processing system 1 of the modified example, after the alkaline aqueous solution L is diffused over the entire surface of the wafer W during etching, the flow rate of the alkaline aqueous solution L supplied to the wafer W is changed.

[0161] Specifically, during the etching process, the control device 4 of the modified embodiment rotates the wafer W at a first predetermined rotational speed and switches the flow rate of the alkaline aqueous solution L supplied from the nozzle 41a to the surface of the wafer W between the first predetermined flow rate and a second predetermined flow rate. The second predetermined flow rate is a predetermined flow rate that is less than the first predetermined flow rate. For example, the second predetermined flow rate is 0.5 L / min. The control device 4 of the modified embodiment switches the flow rate of the alkaline aqueous solution L between the first predetermined flow rate and the second predetermined flow rate multiple times until the etching process is completed.

[0162] In addition, the flow rate that can be changed can be three or more flow rates. In addition, the flow rate can be changed continuously.

[0163] As described above, in the treatment process of the modified example, the flow rate (an example of a supply flow rate) of the alkaline aqueous solution L (an example of an alkaline treatment solution) is changed. This improves the fluidity of the alkaline aqueous solution in the holes H of the wafer W and enhances the replacement efficiency of the alkaline aqueous solution in the holes H of the wafer W. As a result, the etching of the wafer W can be performed more quickly.

[0164] The substrate processing system 1 of the above-described embodiment and the modified example may be used in combination. For example, the substrate processing system 1 may use the weir portion 121 to block the alkaline aqueous solution L, and use the release portion 100 to supply the inert gas to the wafer W. Alternatively, the substrate processing system 1 may use the release portion 100 to supply the inert gas to the wafer W, thereby varying the flow rate of the alkaline aqueous solution L supplied from the nozzle 41 a.

[0165] Furthermore, the embodiments disclosed herein are illustrative in all respects and should not be considered restrictive. In practice, the above embodiments can be implemented in various ways. Furthermore, the above embodiments can be omitted, replaced, and modified in various ways without departing from the scope of the claims and the spirit of the present invention.

Claims

1. A substrate processing method, characterized in that: include: a forming step of supplying an alkali treatment liquid with a reduced oxygen concentration to the periphery of the substrate while supplying a rinse liquid to the center of the substrate while rotating the substrate, then stopping the supply of the alkali treatment liquid with a reduced oxygen concentration and continuing to supply the rinse liquid, thereby replacing the alkali treatment liquid with a reduced oxygen concentration at the periphery of the substrate with the rinse liquid, stopping the supply of the rinse liquid, and then supplying the alkali treatment liquid with a reduced oxygen concentration to the center of the substrate, replacing the rinse liquid with the alkali treatment liquid with a reduced oxygen concentration, and diffusing the alkali treatment liquid with a reduced oxygen concentration to the entire surface of the substrate, thereby forming a liquid film of the alkali treatment liquid with a reduced oxygen concentration on the substrate; and In the treatment step, in a state where the liquid film having a predetermined thickness is formed on the substrate, the alkaline treatment liquid with a reduced oxygen concentration is supplied and the substrate is rotated to etch the substrate.

2. The substrate processing method according to claim 1, wherein: The method includes a gas supplying step of supplying an inert gas to the substrate at least before the forming step.

3. The substrate processing method according to claim 1 or 2, wherein: In the forming step, the substrate is rotated at a first rotation speed. In the processing step, the substrate is rotated at a second rotation speed that is lower than the first rotation speed.

4. The substrate processing method according to claim 1 or 2, wherein: In the treatment step, the supply flow rate of the alkaline treatment solution is changed.

5. The substrate processing method according to claim 1 or 2, wherein: The method comprises a dissolving step of dissolving an inert gas in the alkaline treatment solution.

6. The substrate processing method according to claim 1 or 2, wherein: In the treatment step, the alkaline treatment solution is supplied in a state where the outer periphery of the substrate is surrounded by the dam portion.

7. The substrate processing method according to claim 1 or 2, wherein: The method includes a replacement step of replacing the alkaline treatment liquid of the etched substrate with a rinse liquid.

8. The substrate processing method according to claim 1 or 2, wherein: The oxygen concentration of the alkaline treatment liquid is 0.1 ppm or less.

9. A substrate processing device, characterized in that: include: a holding portion for holding a substrate; a driving portion for rotating the holding portion; A dissolving portion for dissolving the inert gas in the alkaline treatment solution; and The processing section supplies the alkaline treatment solution, in which the oxygen concentration is reduced due to the inert gas, to the substrate to perform etching on the substrate. The processing unit can perform the following steps: a forming step, wherein, while the substrate is rotated by the driving portion, the alkaline treatment liquid with reduced oxygen concentration is supplied to the outer periphery of the substrate and the rinsing liquid is supplied to the center of the substrate, thereafter, the supply of the alkaline treatment liquid with reduced oxygen concentration is stopped and the supply of the rinsing liquid is continued, thereby replacing the alkaline treatment liquid with reduced oxygen concentration at the outer periphery of the substrate with the rinsing liquid, the supply of the rinsing liquid is stopped, and then, the alkaline treatment liquid with reduced oxygen concentration is supplied to the center of the substrate, replacing the rinsing liquid with the alkaline treatment liquid with reduced oxygen concentration, and the alkaline treatment liquid with reduced oxygen concentration is diffused over the entire surface of the substrate, thereby forming a liquid film of the alkaline treatment liquid with reduced oxygen concentration on the substrate; and In the processing step, in a state where the liquid film having a predetermined thickness is formed on the substrate, the alkaline treatment liquid with a reduced oxygen concentration is supplied, and the substrate is rotated by the driving unit to etch the substrate.

10. The substrate processing apparatus according to claim 9, wherein: include: A release portion releases the inert gas toward the substrate.

11. The substrate processing device according to claim 9 or 10, wherein: The processing unit supplies the alkaline treatment liquid containing the inert gas to the substrate while forming a liquid film of the alkaline treatment liquid containing the inert gas to a predetermined thickness, and rotates the substrate.

12. The substrate processing device according to claim 9 or 10, wherein: The processing portion includes a dam portion surrounding the outer periphery of the substrate, The processing unit supplies the alkaline processing liquid containing the inert gas to the substrate in a state where the outer periphery of the substrate is surrounded by the dam portion.

Images