Substrate processing method and substrate processing apparatus

Abstract

To provide a technique for improving the uniformity of the etching amount in the depth direction of holes formed in a substrate.SOLUTION: A substrate processing method according to an embodiment includes a formation step and a treatment step. In the forming step, a liquid film of an alkaline treatment liquid is formed on the substrate by supplying the alkaline treatment liquid having a reduced oxygen concentration to the substrate. In the treatment step, the substrate is etched by rotating the substrate while supplying the alkaline treatment liquid in a state where the liquid film having a predetermined thickness is formed on the substrate.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses supplying an alkaline treatment liquid in which oxygen is dissolved to a substrate and performing an etching treatment.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique for improving the uniformity of the etching amount in the depth direction of holes formed in a substrate.

Means for Solving the Problems

[0005] A substrate processing method according to an aspect of the present disclosure includes a forming step and a processing step. In the forming step, a liquid film of an alkaline treatment liquid is formed on the substrate by supplying the alkaline treatment liquid with a reduced oxygen concentration to the substrate. In the processing step, while supplying the alkaline treatment liquid in a state where a liquid film having a given thickness is formed on the substrate, the substrate is rotated to etch the substrate.

Effects of the Invention

[0006] According to the present disclosure, it is possible to improve the uniformity of the etching amount in the depth direction of holes formed in a substrate.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

[0008] Hereinafter, embodiments of the substrate processing method and the substrate processing apparatus disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that the substrate processing method and the substrate processing apparatus disclosed by the following embodiments are not limited.

[0009] (First Embodiment) <Overview of the Substrate Processing System> First, with reference to FIG. 1, the schematic configuration of the substrate processing system 1 according to the first embodiment will be described. FIG. 1 is a diagram showing the schematic configuration of the substrate processing system 1 according to the first embodiment. Hereinafter, in order to clarify the positional relationship, an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other are defined, and the positive direction of the Z-axis is the vertically upward direction.

[0010] As shown in FIG. 1, the substrate processing system 1 includes a loading / unloading station 2 and a processing station 3 (an example of a substrate processing apparatus). The loading / unloading station 2 and the processing station 3 are provided adjacent to each other.

[0011] The loading / unloading station 2 includes a carrier placement unit 11 and a transfer unit 12. A plurality of carriers C for horizontally accommodating a plurality of substrates, in this embodiment, semiconductor wafers W (hereinafter referred to as wafers W), are placed on the carrier placement unit 11.

[0012] The transfer unit 12 is provided adjacent to the carrier placement unit 11 and includes a substrate transfer device 13 and a delivery unit 14 inside. The substrate transfer device 13 includes a wafer holding mechanism for holding the wafer W. Further, the substrate transfer device 13 can move in the horizontal and vertical directions and turn around the vertical axis, and transfers the wafer W between the carrier C and the delivery unit 14 using the wafer holding mechanism.

[0013] The processing station 3 is provided adjacent to the transfer unit 12. The processing station 3 includes a transfer unit 15 and a plurality of processing units 16 (an example of a processing unit). The plurality of processing units 16 are arranged side by side on both sides of the transfer unit 15.

[0014] The transfer unit 15 includes a substrate transfer device 17 inside. The substrate transfer device 17 includes a wafer holding mechanism for holding the wafer W. Further, the substrate transfer device 17 can move in the horizontal and vertical directions and turn around the vertical axis, and transfers the wafer W between the delivery unit 14 and the processing unit 16 using the wafer holding mechanism.

[0015] The processing unit 16 performs predetermined substrate processing on the wafer W conveyed by the substrate transfer device 17. A dissolving unit 70 that dissolves an inert gas in an alkaline aqueous solution L (an example of an alkali treatment liquid) and supplies it to the processing unit 16 is connected to the processing unit 16. Configuration examples of the processing unit 16 and the dissolving unit 70 will be described later.

[0016] Further, 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.

[0017] The storage unit 19 stores programs for controlling various processes executed in the substrate processing system 1. The storage unit 19 is realized by a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, or a storage device such as a hard disk or an optical disk.

[0018] The control unit 18 controls the operation of the substrate processing system 1 by reading and executing the programs stored in the storage unit 19. The programs may be recorded on 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 hard disks, flexible disks (FDs), compact disks (CDs), magneto-optical disks (MOs), and memory cards.

[0019] In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 of the loading / unloading station 2 takes out the wafer W from the carrier C placed on the carrier placement unit 11 and places the taken-out wafer W on the transfer unit 14. The wafer W placed on the transfer unit 14 is taken out from the transfer unit 14 by the substrate transfer device 17 of the processing station 3 and carried into the processing unit 16.

[0020] The wafer W carried into the processing unit 16 is processed by the processing unit 16, then carried out from the processing unit 16 by the substrate transfer device 17, and placed on the delivery unit 14. Then, the processed wafer W placed on the delivery unit 14 is returned to the carrier C of the carrier placement unit 11 by the substrate transfer device 13.

[0021] <Processing Unit and Mixing Unit> Next, the processing unit 16 and the dissolution unit 70 will be described with reference to FIG. 2. FIG. 2 is a schematic diagram showing the configuration of the processing unit 16 and the dissolution unit 70 according to the first embodiment. As shown in FIG. 2, the processing unit 16 includes a chamber 20, a substrate holding mechanism 30, a processing fluid supply unit 40, and a recovery cup 50.

[0022] The chamber 20 houses the substrate holding mechanism 30, the processing fluid supply unit 40, and the recovery cup 50. An FFU (Fan Filter Unit) 21 is provided on the ceiling of the chamber 20. The FFU 21 forms a downflow inside the chamber 20.

[0023] The substrate holding mechanism 30 includes a holding part 31, a support column part 32, and a driving part 33. The holding part 31 holds the wafer W horizontally. The support column part 32 is a member extending in the vertical direction, the base end part is rotatably supported by the driving part 33, and the holding part 31 is horizontally supported at the tip end part. The driving part 33 rotates the support column part 32 around the vertical axis.

[0024] The substrate holding mechanism 30 rotates the holding part 31 supported by the support column part 32 by rotating the support column part 32 using the driving part 33, thereby rotating the wafer W held by the holding part 31.

[0025] The processing fluid supply unit 40 supplies the processing fluid to the wafer W. Also, the processing fluid supply unit 40 is connected to the dissolution unit 70.

[0026] The recovery cup 50 is arranged to surround the holding part 31 and collects the processing liquid scattered from the wafer W due to the rotation of the holding part 31. A drain port 51 is formed at the bottom of the recovery cup 50, and the processing liquid collected by the recovery cup 50 is discharged to the outside of the processing unit 16 through the drain port 51. Further, an exhaust port 52 for discharging the gas supplied from the FFU 21 to the outside of the processing unit 16 is formed at the bottom of the recovery cup 50.

[0027] The dissolution part 70 includes a chemical solution storage container 71, a circulation line 72, a pump 73, a temperature regulator 74, and a bubbling line 75.

[0028] The chemical solution storage container 71 stores an alkaline aqueous solution (an example of an alkaline processing liquid) L used as an etching solution. The alkaline aqueous solution L contains, for example, at least one of TMAH (TetraMethylAmmonium Hydroxide), an aqueous choline solution, an aqueous KOH (potassium hydroxide) solution, and aqueous ammonia.

[0029] A circulation line 72 for circulating the stored alkaline aqueous solution L is connected to the chemical solution storage container 71. The circulation line 72 is connected to the above-described processing fluid supply unit 40.

[0030] The circulation line 72 is provided with a pump 73 and a temperature regulator 74. The alkaline aqueous solution L adjusted to a predetermined temperature by the temperature regulator 74 circulates through the circulation line 72 by the pump 73. The predetermined temperature is a preset temperature, for example, about 25°C. Note that the predetermined temperature may be higher than 25°C and may be about 80°C.

[0031] Note that a sensor 79 for measuring the oxygen concentration in the alkaline aqueous solution L is provided in the circulation line 72.

[0032] Furthermore, a bubbling line 75 for bubbling an inert gas into the alkaline aqueous solution L stored in the chemical liquid storage container 71 is connected to the chemical liquid storage container 71. The inert gas is, for example, nitrogen.

[0033] A valve 76 and a flow rate regulator 77 are provided in the bubbling line 75. The bubbling line 75 supplies an inert gas from an inert gas supply source 78 to the chemical liquid storage container 71 via the valve 76 and the flow rate regulator 77.

[0034] The inert gas supplied from the bubbling line 75 dissolves in the alkaline aqueous solution L. That is, the dissolution part 70 dissolves the inert gas in the alkaline aqueous solution L. The oxygen concentration of the alkaline aqueous solution L is reduced by the dissolution of the inert gas.

[0035] Next, a specific configuration example of the processing unit 16 will be described with reference to FIG. 3. FIG. 3 is a schematic diagram showing a specific configuration example of the processing unit 16 according to the first embodiment.

[0036] As shown in FIG. 3, a holding member 311 for holding the wafer W from the side is provided on the upper surface of the holding part 31 included in the substrate holding mechanism 30. The wafer W is horizontally held in a state slightly separated from the upper surface of the holding part 31 by the holding member 311. Note that the wafer W is held by the holding part 31 with the surface on which the etching process is to be performed facing upward.

[0037] The processing fluid supply unit 40 includes a plurality (here, four) of nozzles 41a to 41d, an arm 42 that horizontally supports the nozzles 41a to 41d, and a turning and elevating mechanism 43 that turns and elevates the arm 42.

[0038] The nozzle 41a is connected to the above-described dissolution part 70 via a valve 44a and a flow rate regulator 45a. The nozzle 41b is connected to a DIW supply source 46b via a valve 44b and a flow rate regulator 45b. DIW (DeIonized Water) is used, for example, for rinsing.

[0039] The nozzle 41c is connected to a DHF supply source 46c via a valve 44c and a flow regulator 45c. DHF (Diluted HydroFluoric acid) is used, for example, in an oxide film removal process. The nozzle 41d is connected to an IPA supply source 46d via a valve 44d and a flow regulator 45d. IPA (IsoPropyl Alcohol) is used, for example, in a drying process.

[0040] The nozzle 41a discharges the alkaline aqueous solution L supplied from the dissolution unit 70. The nozzle 41b discharges the DIW supplied from the DIW supply source 46b. The nozzle 41c discharges the DHF supplied from the DHF supply source 46c. The nozzle 41d discharges the IPA supplied from the IPA supply source 46d.

[0041] The processing unit 16 (an example of a processing section) supplies an alkaline aqueous solution L (an example of an alkaline treatment liquid) containing an inert gas to a wafer W (an example of a substrate), and etches 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 in a state where a liquid film of the alkaline aqueous solution L containing an inert gas is formed to a predetermined thickness (a given thickness). Details of the etching process will be described later.

[0042] <Substrate Processing> Next, the etching solution generation process according to the first embodiment will be described with reference to the flowchart of FIG. 4. FIG. 4 is a flowchart for explaining the etching solution generation process according to the first embodiment.

[0043] 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 through the circulation line 72. Further, the control device 4 adjusts the temperature of the alkaline aqueous solution L to a predetermined temperature by the temperature regulator 74.

[0044] The control device 4 performs a dissolution process (S101). The control device 4 supplies an inert gas to the alkaline aqueous solution L (an example of an alkali treatment solution). Specifically, the control device 4 supplies an inert gas from the bubbling line 75 to the alkaline aqueous solution L in the chemical solution storage container 71, dissolves the inert gas in the alkaline aqueous solution L, and reduces the oxygen concentration of the alkaline aqueous solution L. The control device 4 measures the oxygen concentration of the alkaline aqueous solution L circulating through the circulation line 72 with the sensor 79, and supplies an inert gas from the bubbling line 75 so that the oxygen concentration of the alkaline aqueous solution L becomes equal to or lower than a predetermined concentration. The predetermined concentration is a preset concentration, specifically, 0.1 ppm. That is, the oxygen concentration of the alkaline aqueous solution L is 0.1 ppm or less. Note that the temperature adjustment process and the mixing process may be executed as one process. Also, the temperature adjustment process and the mixing process may be included in the substrate process described below.

[0045] Next, the substrate process according to the first embodiment will be described with reference to the flowchart of FIG. 5. FIG. 5 is a flowchart for explaining the substrate process according to the first embodiment.

[0046] The control device 4 performs a loading process (S200). The control device 4 loads the wafer W into the chamber 20 of the processing unit 16 by the substrate transfer device 17. The wafer W is held by the holding member 311 with the surface to be etched facing upward. Thereafter, the control device 4 controls the drive unit 33 to rotate the substrate holding mechanism 30. That is, the control device 4 rotates the wafer W.

[0047] The control device 4 performs an oxide film removal process (S201). The control device 4 moves the nozzle 41c of the processing fluid supply unit 40 above the center of the wafer W. The control device 4 supplies DHF, which is an etching solution, from the nozzle 41c to the surface of the wafer W.

[0048] The DHF supplied to the surface of the wafer W spreads over the entire surface of the wafer W due to the centrifugal force accompanying the rotation of the wafer W. Thereby, the natural oxide film formed on the wafer W is removed by the DHF.

[0049] The control device 4 performs the first lens process (S202). The control device 4 moves the nozzle 41b of the processing fluid supply unit 40 above the center of the wafer W. The control device 4 supplies DIW to the surface of the wafer W from the nozzle 41b. The DIW supplied to the surface of the wafer W replaces the DHF remaining on the surface of the wafer W.

[0050] The control device 4 performs an etching process (S203). The control device 4 supplies an alkaline aqueous solution L with a reduced oxygen concentration to the surface of the wafer W and etches the wafer W with the alkaline aqueous solution L.

[0051] First, the control device 4 spreads the alkaline aqueous solution L over the entire surface of the wafer W to form 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 above 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 predetermined flow rate while rotating the wafer W at a first predetermined rotation speed. The first predetermined flow rate is a preset flow rate, for example, 1.5 L / min. The first predetermined rotation speed is a preset rotation speed, for example, set to a rotation speed of 500 rpm or more. The first predetermined rotation speed in the present embodiment is, for example, 1000 rpm.

[0052] The alkaline aqueous solution L supplied to the surface of the wafer W spreads over the entire surface of the wafer W due to the centrifugal force accompanying the rotation of the wafer W to form a liquid film. Note that the time for rotating the wafer W at the first predetermined rotation speed may be any time as long as the alkaline aqueous solution L spreads over the entire surface of the wafer W, and a short time such as 2 seconds may be sufficient.

[0053] Next, the control device 4 etches the wafer W in a state where the thickness of the liquid film of the alkaline aqueous solution L formed on the surface of the wafer W is equal to or greater than a predetermined thickness. Specifically, the control device 4 rotates the wafer W at a second predetermined rotational speed. The predetermined thickness is a preset thickness, for example, 400 μm or more. The second predetermined rotational speed is a preset rotational speed and is smaller than the first predetermined rotational speed. The second predetermined rotational speed is set to be, for example, less than 500 rpm. In the present embodiment, the second predetermined rotational speed is set to be greater than 0 rpm and 30 rpm or less, for example.

[0054] The control device 4 etches the wafer W while rotating the wafer W and supplying the alkaline aqueous solution L from the nozzle 41a in a state where a liquid film of the alkaline aqueous solution L having a thickness equal to or greater than a predetermined thickness is formed.

[0055] 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.

[0056] When DIW is supplied to the surface of the wafer W, the alkaline aqueous solution L remaining on the surface of the wafer W is replaced with DIW.

[0057] The control device 4 performs a drying process (S205). The control device 4 moves the nozzle 41d of the process fluid supply unit 40 above the center of the wafer W. The control device 4 supplies IPA to the surface of the wafer W from the nozzle 41d while rotating the substrate holding mechanism 30 at a predetermined rotational speed. After supplying IPA for a predetermined time, the control device 4 stops the supply of IPA and spin-dries the wafer W.

[0058] When IPA is supplied to the surface of the wafer W, the DIW remaining on the surface of the wafer W is replaced with IPA. Note that the control device 4 may spin-dry the wafer W without supplying IPA.

[0059] The control device 4 performs the unloading process (S206). After the control device 4 controls the drive unit 33 to stop the rotation of the wafer W, it controls the substrate transfer device 17 to unload the wafer W from the processing unit 16. When the unloading process is completed, a series of substrate processes for one wafer W are completed.

[0060] When etching is performed using the alkaline aqueous solution L, it is known that oxygen contained in the alkaline aqueous solution L is adsorbed on the wafer W and an oxide film F is formed.

[0061] Here, a comparative example in which the substrate process according to the first embodiment is not performed will be described. In the substrate process according to the comparative example, the oxygen concentration of the alkaline aqueous solution L is not reduced, and the thickness of the liquid film of the alkaline aqueous solution L is not maintained at a predetermined thickness or more. In the chamber 20, a downflow is formed by the FFU 21, so that oxygen is dissolved from the surface of the liquid film of the alkaline aqueous solution L, and the oxygen concentration becomes high near the surface of the liquid film of the alkaline aqueous solution L.

[0062] Therefore, in the substrate process according to the comparative example, oxygen adsorption increases near the opening of the hole H of the wafer W, and as shown in FIG. 6A, the formed oxide film F becomes thick. FIG. 6A is a schematic diagram of the hole H of the wafer W in the substrate process according to the comparative example.

[0063] Further, in the substrate process according to the comparative example, since oxygen is adsorbed near the opening of the hole H of the wafer W, the oxygen concentration of the alkaline aqueous solution L becomes lower at the bottom side of the hole H of the wafer W than near the opening. As a result, on the bottom side of the hole H of the wafer W, the thickness of the formed oxide film F becomes thinner than that on the opening side, and the difference between the etching amount on the opening side of the hole H of the wafer W and the etching amount on the bottom side of the hole H of the wafer W becomes large. Therefore, in the substrate process according to the comparative example, the etching ratio 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 large.

[0064] In contrast, in the substrate processing according to the first embodiment, etching is performed using an alkaline aqueous solution L in which an inert gas is dissolved and the oxygen concentration is reduced. Therefore, in the substrate processing according to the first embodiment, oxygen adsorption near the opening of the hole H in the wafer W is suppressed.

[0065] Also, while supplying the alkaline aqueous solution L with the thickness of the liquid film of the alkaline aqueous solution L formed on the surface of the wafer W being equal to or greater than a predetermined thickness, the wafer W is rotated to perform etching. As a result, in the substrate processing according to the first embodiment, even when oxygen dissolves from the surface of the liquid film of the alkaline aqueous solution L, the distance between the oxygen near the surface of the liquid film of the alkaline aqueous solution L and the opening of the hole H in the wafer W becomes longer. Therefore, in the substrate processing according to the first embodiment, oxygen adsorption near the opening of the hole H in the wafer W is suppressed.

[0066] In the substrate processing according to the first embodiment, as shown in FIG. 6B, formation of the oxide film F near the opening of the hole H in the wafer W is suppressed. Therefore, in the substrate processing according to 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 becomes smaller. Therefore, in the substrate processing according to the first embodiment, the etching ratio becomes smaller. FIG. 6B is a schematic diagram of the hole H in the wafer W in the substrate processing according to the first embodiment.

[0067] Also, FIG. 7 shows the simulation results of the oxygen concentration at the opening of the hole H in the wafer W and the etching ratio. FIG. 7 is the simulation result in the substrate processing according to the first embodiment. In FIG. 7, the etching ratio is shown when nitrogen is dissolved as an inert gas in the alkaline aqueous solution L to change the oxygen concentration of the alkaline aqueous solution L. In the simulation shown in FIG. 7, the rotation speed of the wafer W is 30 rpm.

[0068] As shown in FIG. 7, when the oxygen concentration at the opening of the hole H in the wafer W decreases, the etching ratio approaches "1". When the oxygen concentration of the alkaline aqueous solution L is 0.1 ppm or less, the etching ratio is small, and the uniformity of the etching amount on the bottom side and the opening side of the hole H can be improved. That is, the uniformity of the etching amount in the depth direction of the hole H in the wafer W can be improved.

[0069] Also, in the substrate processing according to the first embodiment, after spreading the alkaline aqueous solution L over the entire surface of the wafer W, the rotational speed of the substrate is set to 30 rpm, and etching processing is performed.

[0070] Here, the relationship between the rotational speed of the wafer W and the etching amount is shown in FIG. 8. FIG. 8 is a diagram showing the relationship between the rotational speed of the wafer W and the etching amount in the substrate processing according to the first embodiment. In FIG. 8, the etching amounts in the cases where the rotational speeds of the wafer W are 1000 rpm, 500 rpm, and 200 rpm are shown.

[0071] As shown in FIG. 8, when the rotational speed of the wafer W is decreased, the difference in the etching amount with respect to the distance from the center of the wafer W can be decreased. That is, when the rotational speed of the wafer W is decreased, the in-plane uniformity, which is the uniformity of the etching amount in the radial direction of the wafer W, can be improved.

[0072] As described above, the substrate processing method according to the first embodiment includes a forming step and a processing step. The forming step forms a liquid film of the alkaline aqueous solution L on the wafer W (an example of a substrate) by supplying the alkaline aqueous solution L (an example of an alkali treatment liquid) with a reduced oxygen concentration to the wafer W. The processing step rotates the wafer W while supplying the alkaline aqueous solution L in a state where a liquid film of a predetermined thickness (a given thickness) is formed on the wafer W to etch the wafer W. Specifically, the oxygen concentration of the alkaline aqueous solution L is 0.1 ppm or less.

[0073] As a result, formation of the oxide film F near the opening of the hole H in the wafer W can be suppressed. 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.

[0074] Also, in the forming step, the wafer W is rotated at a first rotation speed. Further, in the processing step, the wafer W is rotated at a second rotation speed smaller than the first rotation speed.

[0075] As a result, a liquid film of the alkaline aqueous solution L can be quickly formed over the entire wafer W, and oxygen reaching inside the hole H can be suppressed. Also, a liquid film of the alkaline aqueous solution L having a thickness equal to or greater than a predetermined thickness can be formed on the wafer W, and formation of the oxide film F near the opening of the hole H in the wafer W can be suppressed. 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. Further, by setting the rotation speed of the wafer W to the second rotation speed, the liquid surface of the alkaline aqueous solution L can be suppressed from fluctuating, and oxygen being mixed into the alkaline aqueous solution L can be suppressed.

[0076] Also, the substrate processing method includes a dissolving step. In the dissolving step, an inert gas is dissolved in the alkaline aqueous solution L.

[0077] As a result, the oxygen concentration of the alkaline aqueous solution L supplied to the wafer W can be reduced. 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.

[0078] Also, the substrate processing method includes a replacing step. In the replacing step, the alkaline aqueous solution L on the wafer W subjected to the etching process is replaced with DIW (an example of a rinse liquid). Thereby, the etching process of the wafer W can be terminated.

[0079] Further, a processing station 3 (an example of a substrate processing apparatus) includes a dissolution unit 70 and a processing unit 16 (an example of a processing unit). The dissolution unit 70 mixes an inert gas into an alkaline aqueous solution L (an example of an alkali treatment liquid).

[0080] Thereby, the processing unit 16 can suppress the formation of the oxide film F near the opening of the hole H of the wafer W. Therefore, the processing unit 16 can reduce the difference in the etching amount in the depth direction of the hole H of the wafer W and improve the uniformity of the etching amount in the depth direction of the hole H.

[0081] (Second Embodiment) Next, the substrate processing system 1 according to the second embodiment will be described. Here, the parts different from the substrate processing system 1 according to the first embodiment will be described. For the same configurations as those of the substrate processing system 1 according to the first embodiment, the same reference numerals as those of the substrate processing system 1 according to the first embodiment are given, and detailed descriptions are omitted.

[0082] <Processing Unit> As shown in FIG. 9, the processing unit 16 according to the second embodiment includes a discharge unit 100 that discharges an inert gas toward a wafer W (an example of a substrate). FIG. 9 is a schematic diagram showing the configuration of the processing unit 16 according to the second embodiment. The inert gas is nitrogen.

[0083] The discharge unit 100 includes a nozzle 101, an arm 102 that supports the nozzle 101, and a turning mechanism 103 that turns the arm 102. Note that the turning mechanism 103 may raise and lower the arm 102.

[0084] The nozzle 101 is connected to an inert gas supply source 106 via a valve 104 and a flow regulator 105. The nozzle 101 discharges an inert gas toward the wafer W. Note that the inert gas supply source 106 may be the same as the inert gas supply source 78 (see FIG. 2) that supplies the inert gas to the bubbling line 75 (see FIG. 2). That is, the inert gas supplied to the alkaline aqueous solution L and the inert gas discharged onto the wafer W by the nozzle 101 may be supplied from the same inert gas supply source.

[0085] <Substrate processing> Next, the substrate processing according to the second embodiment will be described. Note that the overall procedure of the substrate processing according to the second embodiment is the same as that of the substrate processing according to the first embodiment shown in FIG. 5.

[0086] In the etching process (FIG. 5, S203), when the control device 4 spreads the alkaline aqueous solution L over the entire surface of the wafer W, the control device 4 supplies the alkaline aqueous solution L while discharging an inert gas from the discharge unit 100. For example, after discharging the inert gas from the discharge unit 100 onto the surface of the wafer W, the control device 4 supplies the alkaline aqueous solution L from the nozzle 41a to spread the alkaline aqueous solution L over the entire surface of the wafer W.

[0087] When the inert gas is discharged from the discharge unit 100 toward the wafer W, an inert gas layer is formed on the surface of the wafer W. Therefore, oxygen dissolved in the liquid film of the alkaline aqueous solution L formed on the surface of the wafer W is reduced.

[0088] Note that the discharge of the inert gas from the discharge unit 100 onto the surface of the wafer W may be performed throughout the etching process. When the control device 4 supplies the alkaline aqueous solution L to the surface of the wafer W at a first predetermined flow rate from the nozzle 41a, the control device 4 may also discharge the inert gas toward the wafer W from the discharge unit 100. The control device 4 supplies the inert gas toward the wafer W (an example of a substrate) at least before forming the liquid film of the alkaline aqueous solution L on the wafer W.

[0089] The substrate processing method according to the second embodiment includes a gas supply step of supplying an inert gas toward a wafer W (an example of a substrate) at least before the forming step.

[0090] Thereby, oxygen dissolution in the liquid film of the alkaline aqueous solution L formed on the surface of the wafer W can be suppressed, and formation of the oxide film F near the opening of the hole H in the wafer W can be suppressed. 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.

[0091] (Third Embodiment) Next, the substrate processing system 1 according to the third embodiment will be described. Here, the parts different from the substrate processing system 1 according to the first embodiment will be described. The same components as 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 description thereof will be omitted.

[0092] <Processing Unit> As shown in FIG. 10, in the processing unit 16 according to the third embodiment, a nozzle 41a for discharging the alkaline aqueous solution L is supported by an arm 110. FIG. 10 is a schematic diagram showing the configuration of the processing unit 16 according to the third embodiment.

[0093] The arm 110 rotates and moves up and down by a swing lifting 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.

[0094] <Substrate Processing> Next, the etching process according to the third embodiment will be described. Note that the overall procedure of the substrate processing according to the third embodiment is the same as that of the substrate processing according to the first embodiment shown in FIG. 5.

[0095] In the etching process (Fig. 5, S203), the control device 4 arranges the nozzle 41a above the outer peripheral portion of the wafer W, supplies the alkaline aqueous solution L to the outer peripheral portion of the wafer W, and etches the outer peripheral portion of the wafer W with the alkaline aqueous solution L. Further, the control device 4 arranges the nozzle 41b above the central portion of the wafer W and supplies DIW to the central portion of the wafer W.

[0096] That is, the control device 4 supplies DIW to the central portion of the wafer W while supplying the alkaline aqueous solution L to the outer peripheral portion of the wafer W. Note that the control device 4 rotates the wafer W at a second predetermined rotation speed and supplies DIW and the alkaline aqueous solution L to the wafer W. The second predetermined rotation speed is set to a rotation speed smaller than 500 rpm as described above, for example, a rotation speed of 200 rpm or less. Further, the control device 4 supplies DIW and the alkaline aqueous solution L for a predetermined time. The predetermined time is a preset time, for example, 120 seconds.

[0097] Thereafter, the control device 4 stops the supply of the alkaline aqueous solution L and continues the supply of DIW. As a result, the alkaline aqueous solution L on the outer peripheral portion of the wafer W is replaced with DIW.

[0098] When the replacement with DIW is completed, the control device 4 stops the supply of DIW and arranges the nozzle 41a at the central portion of the wafer W. Then, the control device 4 supplies the alkaline aqueous solution L from the nozzle 41a to the surface of the wafer W, replaces DIW with the alkaline aqueous solution L, and spreads the alkaline aqueous solution L over the entire surface of the wafer W. That is, the processing unit 16 (an example of a processing section) supplies the alkaline aqueous solution L (an example of an alkali treatment liquid) to the outer peripheral portion of the wafer W (an example of a substrate), and after stopping the supply of the alkaline aqueous solution L to the outer peripheral portion, supplies the alkaline aqueous solution L to the central portion of the wafer W.

[0099] Thereafter, similar to the first embodiment, the control device 4 supplies the alkaline aqueous solution L to the surface of the wafer W from the nozzle 41a at a first predetermined flow rate while rotating the wafer W at a second predetermined rotational speed. The second predetermined rotational speed is set to a rotational speed smaller than, for example, 500 rpm, similar to the first embodiment. The second predetermined rotational speed is set to be larger than, for example, 0 rpm and equal to or less than 30 rpm.

[0100] In the formation step of the substrate processing method according to the third embodiment, the alkaline aqueous solution L (an example of an alkali treatment liquid) is supplied to the outer peripheral portion of the wafer W (an example of a substrate), and after the supply of the alkaline aqueous solution L to the outer peripheral portion is stopped, the alkaline aqueous solution L is supplied to the central portion of the wafer W. Thereby, before supplying the alkaline aqueous solution L from the central portion of the wafer W, the outer peripheral portion of the wafer W is etched in advance. Therefore, when the alkaline aqueous solution L is supplied to the central portion of the wafer W for etching treatment, the in-plane uniformity of the wafer W can be improved.

[0101] (Fourth Embodiment) Next, the substrate processing system 1 according to the fourth embodiment will be described. Here, the parts different from the substrate processing system 1 according to the first embodiment will be described. The same components as 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 are omitted.

[0102] <Processing Unit> As shown in FIG. 11, the processing unit 16 according to the fourth embodiment includes a weir mechanism 120. FIG. 11 is a schematic diagram showing the configuration 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 portion 123, and a moving mechanism 124.

[0103] The weir portion 121 is formed in a cylindrical shape. The weir portion 121 is disposed inside the recovery cup 50. Further, the weir portion 121 is disposed on the outer periphery of the holding portion 31. That is, the weir portion 121 surrounds the outer periphery of the wafer W held by the holding portion 31. The weir portion 121 suppresses the alkaline aqueous solution L supplied to the wafer W from flowing out of the wafer W. That is, the weir portion 121 dams up the outflow of the alkaline aqueous solution L from the wafer W. In order to prevent interference between the weir portion 121 and the holding portion 31, a gap is formed between the weir portion 121 and the holding portion 31.

[0104] 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.

[0105] The support column portion 123 extends in the vertical direction and is connected to the second support member 122b. The support column portion 123 supports the support portion 122 and the weir portion 121. The support column portion 123 is formed in a cylindrical shape, and the support column portion 32 of the substrate holding mechanism 30 is inserted therein.

[0106] The moving mechanism 124 moves the support column portion 123 along the vertical direction. That is, the moving mechanism 124 moves the support portion 122 and the weir portion 121 along the vertical direction via the support column portion 123. Specifically, the moving mechanism 124 moves the weir portion 121 between a retracted position and a damming position. The retracted position is a position where the upper end surface of the weir portion 121 is lower than the upper surface of the wafer W. The damming position is a position where the upper end surface of the weir portion 121 is higher than the upper surface of the wafer W. For example, the damming position is a position where the upper end surface of the weir portion 121 is higher than the upper surface of the wafer W by a predetermined thickness or more.

[0107] During the etching process, the weir mechanism 120 positions the weir portion 121 at the damming position, and the weir portion 121 dams up the alkaline aqueous solution L on the wafer W.

[0108] In this way, the processing unit 16 (an example of a processing section) supplies the alkaline aqueous solution L (an example of an alkali treatment liquid) containing an inert gas to the wafer W (an example of a substrate) while surrounding the outer periphery of the wafer W with the weir portion 121.

[0109] <Substrate Processing> Next, the substrate processing according to the fourth embodiment will be described. Note that the overall procedure of the substrate processing according to the fourth embodiment is the same as that of the substrate processing according to the first embodiment.

[0110] In the etching process (FIG. 5, S203), the control device 4 moves the weir portion 121 of the weir mechanism 120 from the retracted position to the blocking position to supply the alkaline aqueous solution L to the wafer W.

[0111] The alkaline aqueous solution L is blocked by the weir portion 121 to form a liquid film having a thickness equal to or greater than a predetermined thickness on the surface of the wafer W. Although a part 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 thickness equal to or greater than a predetermined thickness is formed on the surface of the wafer W.

[0112] The control device 4 rotates the wafer W at a second predetermined rotational speed while supplying the alkaline aqueous solution L from the nozzle 41a at a first predetermined flow rate. Further, the control device 4 supplies the alkaline aqueous solution L from the nozzle 41a while swinging the arm 42 that supports the nozzle 41a.

[0113] In this way, by supplying the alkaline aqueous solution L, the thickness of the liquid film formed on the wafer W is maintained at a predetermined thickness or more, and the etching process is performed. Since the alkaline aqueous solution L is blocked by the weir portion 121 and supplied from the nozzle 41a, it overflows from the weir portion 121.

[0114] In the processing step of the substrate processing method according to the fourth embodiment, an alkaline aqueous solution L (an example of an alkali treatment liquid) is supplied while the outer periphery of a wafer W (an example of a substrate) is surrounded by a weir portion 121.

[0115] Thereby, while maintaining the thickness of the liquid film of the alkaline aqueous solution L at a predetermined thickness or more by the weir portion 121, the alkaline aqueous solution L containing oxygen existing near the liquid surface of the liquid film of the alkaline aqueous solution L can be overflowed from the weir portion 121. Therefore, the formation of the oxide film F near the opening of the hole H of the wafer W can be suppressed, the difference in the etching amount in the depth direction of the hole H of the wafer W can be reduced, and the uniformity of the etching amount in the depth direction of the hole H can be improved.

[0116] (Modification example) In the etching process, the substrate processing system 1 according to the modification example changes the flow rate of the alkaline aqueous solution L supplied to the wafer W after spreading the alkaline aqueous solution L over the entire surface of the wafer W.

[0117] Specifically, in the etching process, the control device 4 according to the modification example rotates the wafer W at a first predetermined rotation 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 a first predetermined flow rate and a second predetermined flow rate. The second predetermined flow rate is a preset flow rate and is less than the first predetermined flow rate. For example, the second predetermined flow rate is 0.5 L / min. The control device 4 according to the modification example changes the flow rate of the alkaline aqueous solution L between the first predetermined flow rate and the second predetermined flow rate a plurality of times until the etching process is completed.

[0118] Note that the flow rates to be changed may be three or more flow rates. Also, the flow rate is changed continuously.

[0119] As described above, the processing steps according to the modified example change the flow rate (an example of the supply flow rate) of the alkaline aqueous solution L (an example of the alkali treatment liquid). Thereby, the fluidity of the alkaline aqueous solution in the hole H of the wafer W can be improved, and the replaceability of the alkaline aqueous solution in the hole H of the wafer W can be improved. Therefore, the etching of the wafer W can be performed quickly.

[0120] The substrate processing system 1 according to the above-described embodiment and modified example may be combined and applied. For example, the substrate processing system 1 may dam the alkaline aqueous solution L by the weir portion 121 and supply an inert gas to the wafer W by the discharge portion 100. Further, the substrate processing system 1 may supply an inert gas to the wafer W by the discharge portion 100 and change the flow rate of the alkaline aqueous solution L supplied from the nozzle 41a.

[0121] It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. In fact, the above-described embodiments can be embodied in various forms. Further, the above embodiments may be omitted, replaced, or changed in various forms without departing from the scope and spirit of the appended claims.

Description of Reference Numerals

[0122] 1 Substrate processing system 3 Processing station 4 Control device 16 Processing unit (processing section) 18 Control section 70 Dissolving section 71 Chemical solution storage container 75 Bubbling line 78 Inert gas supply source 100 Discharge portion 106 Inert gas supply source 120 Weir mechanism 121 Weir portion

Claims

1. A supply step of supplying an alkali treatment liquid with a reduced oxygen concentration to the outer peripheral portion of a substrate and supplying a rinse liquid to the central portion of the substrate; A rotation step of rotating the substrate while supplying the alkali treatment liquid and the rinse liquid. The method includes: The supply step is: After supplying the alkali treatment liquid to the outer peripheral portion of the substrate and supplying the rinse liquid to the central portion of the substrate, the supply of the alkali treatment liquid is stopped and the supply of the rinse liquid is continued. A substrate processing method in which, after the replacement of the alkali treatment liquid with the rinse liquid on the substrate is completed, the alkali treatment liquid is supplied to the central portion of the substrate.

2. The rotation step rotates the substrate at 500 rpm or less. The substrate processing method according to Claim 1.

3. A supply unit that supplies an alkali treatment liquid with a reduced oxygen concentration to the outer peripheral portion of a substrate and supplies a rinse liquid to the central portion of the substrate; A drive unit that rotates the substrate while supplying the alkali treatment liquid and the rinse liquid. The apparatus includes: The supply unit is: After supplying the alkali treatment liquid to the outer peripheral portion of the substrate and supplying the rinse liquid to the central portion of the substrate, the supply of the alkali treatment liquid is stopped and the supply of the rinse liquid is continued. A substrate processing apparatus in which, after the replacement of the alkali treatment liquid with the rinse liquid on the substrate is completed, the alkali treatment liquid is supplied to the central portion of the substrate.

Images