阅读说明：本技术 基片处理方法和基片处理装置 (Substrate processing method and substrate processing apparatus ) 是由 日高章一郎 于 2020-10-27 设计创作，主要内容包括：本发明提供基片处理方法和基片处理装置。实施方式的基片处理方法包括形成工序和处理工序。在形成工序中,通过将降低了氧浓度的碱处理液供给到基片,在基片形成碱处理液的液膜。在处理工序中,在基片形成有给定的厚度的液膜的状态下,供给碱处理液并且使基片旋转来对基片进行蚀刻。本发明能够提高形成于基片的孔的深度方向上的蚀刻量的均匀性。(The invention provides a substrate processing method and a substrate processing apparatus. The substrate processing method of an embodiment includes a forming process and a processing process. In the forming step, the alkali treatment liquid having a reduced oxygen concentration is supplied to the substrate, thereby forming a liquid film of the alkali treatment liquid on the substrate. In the treatment step, the substrate is etched by supplying the alkali treatment solution while rotating the substrate in a state where a liquid film having a predetermined thickness is formed on the substrate. The invention can improve the uniformity of etching amount in the depth direction of the hole formed on the substrate.)

1. A method of processing a substrate, comprising:

a forming step of forming a liquid film of an alkali treatment liquid on a substrate by supplying the alkali treatment liquid with a reduced oxygen concentration to the substrate; and

and a treatment step of supplying the alkali treatment solution to the substrate in a state where the liquid film having a predetermined thickness is formed on the substrate, and rotating the substrate to etch the substrate.

2. The substrate processing method according to claim 1, wherein:

the method includes a gas supply step of supplying an inert gas to the substrate at least before the formation step.

3. The substrate processing method according to claim 1 or 2, wherein:

in the forming step, the alkali treatment liquid is supplied to the outer peripheral portion of the substrate, and after the supply of the alkali treatment liquid to the outer peripheral portion is stopped, the alkali treatment liquid is supplied to the central portion of the substrate.

4. A substrate processing method according to any one of claims 1 to 3, characterized in that:

in the forming process, the substrate is rotated at a first rotation speed,

in the processing step, the substrate is rotated at a second rotation speed lower than the first rotation speed.

5. The substrate processing method according to any one of claims 1 to 4, wherein:

in the treatment step, the supply flow rate of the alkali treatment liquid is changed.

6. The substrate processing method according to any one of claims 1 to 5, wherein:

comprising a dissolving step of dissolving an inert gas in the alkali treatment liquid.

7. The substrate processing method according to any one of claims 1 to 6, wherein:

in the treatment step, the alkali treatment solution is supplied while surrounding the outer periphery of the substrate with a weir portion.

8. The substrate processing method according to any one of claims 1 to 7, wherein:

comprises a replacement step of replacing the alkali treatment liquid of the substrate subjected to the etching with a rinse liquid.

9. The substrate processing method according to any one of claims 1 to 8, wherein:

the oxygen concentration of the alkali treatment liquid is 0.1ppm or less.

10. A substrate processing apparatus, comprising:

a dissolving part for dissolving the inactive gas in the alkali treatment solution; and

and a processing unit configured to supply the alkali treatment liquid containing the inert gas to a substrate and perform an etching process on the substrate.

11. The substrate processing apparatus according to claim 10, comprising:

a releasing portion that releases the inactive gas to the substrate.

12. The substrate processing apparatus according to claim 10 or 11, wherein:

the processing unit supplies the alkali treatment solution containing the inert gas to the substrate while rotating the substrate in a state where a liquid film of the alkali treatment solution containing the inert gas is formed to a predetermined thickness.

13. The substrate processing apparatus according to any one of claims 10 to 12, wherein:

the processing unit supplies the alkali treatment liquid containing the inert gas to the central portion of the substrate after supplying the alkali treatment liquid containing the inert gas to the outer peripheral portion of the substrate.

14. The substrate processing apparatus according to any one of claims 10 to 13, wherein:

the processing section has a weir portion surrounding the outer periphery of the substrate,

the treatment unit supplies the alkali treatment solution containing the inert gas to the substrate in a state where the outer periphery of the substrate is surrounded by the weir unit.

Technical Field

The present invention relates to a substrate processing method and a substrate processing apparatus.

Background

Patent document 1 discloses a technique of supplying an alkali treatment solution in which oxygen is dissolved to a substrate to perform an etching treatment.

Documents of the prior art

Patent document 1: japanese patent laid-open publication No. 2019-12802

Disclosure of Invention

Technical problem to be solved by the invention

The invention provides a technique for improving uniformity of etching amount in a depth direction of a hole formed in a substrate.

Technical solution for solving technical problem

A substrate processing method according to an embodiment of the present invention includes a forming step and a processing step. In the forming step, the alkali treatment liquid having a reduced oxygen concentration is supplied to the substrate, thereby forming a liquid film of the alkali treatment liquid on the substrate. In the treatment step, the substrate is etched by supplying the alkali treatment solution while rotating the substrate in a state where a liquid film having a predetermined thickness is formed on the substrate.

Effects of the invention

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.

Drawings

Fig. 1 is a diagram showing a schematic configuration of a substrate processing system according to a first embodiment.

Fig. 2 is a schematic diagram showing the configuration of the processing unit and the mixing section in the first embodiment.

Fig. 3 is a schematic diagram showing a specific configuration example of the processing unit according to the first embodiment.

Fig. 4 is a flowchart illustrating an etching liquid generation process according to the first embodiment.

Fig. 5 is a flowchart illustrating substrate processing of the first embodiment.

Fig. 6A is a schematic view of holes of a wafer in substrate processing of a comparative example.

Fig. 6B is a schematic view of the holes of the wafer in the substrate processing of the first embodiment.

Fig. 7 is a simulation result in the substrate processing of the first embodiment.

Fig. 8 is a graph showing a relationship between the number of rotations of the wafer and the etching amount in the substrate processing of the first embodiment.

Fig. 9 is a schematic diagram showing the configuration of a processing unit according to the second embodiment.

Fig. 10 is a schematic diagram showing the configuration of a processing unit according to the third embodiment.

Fig. 11 is a schematic diagram showing the configuration of a processing unit according to the fourth embodiment.

Description of the reference numerals

1 substrate processing system

3 treatment station

4 control device

16 processing unit (processing unit)

18 control part

70 dissolution part

71 liquid medicine storage container

75 foaming pipeline

78 supply of inert gas

100 release part

106 supply of inert gas

120 weir device

121 dykes.

Detailed Description

Embodiments of the substrate processing method and the substrate processing apparatus disclosed in the present invention will be described in detail below with reference to the attached drawings. Further, the substrate processing method and the substrate processing apparatus disclosed by the embodiments shown below are not limited.

(first embodiment)

< overview of substrate processing System >

First, a schematic configuration of a substrate processing system 1 according to a first embodiment will be described with reference to fig. 1. Fig. 1 is a diagram showing a schematic configuration of a substrate processing system 1 according to a first embodiment. Hereinafter, in order to clarify the positional relationship, an X axis, a Y axis, and a Z axis orthogonal to each other are specified, and the Z axis normal direction is set as the vertically upward direction.

As shown in fig. 1, a substrate processing system 1 includes a carry-in-and-out station 2 and a processing station 3 (an example of a substrate processing apparatus). The in-and-out station 2 is disposed adjacent to the processing station 3.

The carry-in and carry-out station 2 includes a carrier placing portion 11 and a conveying portion 12. The carrier placement unit 11 is configured to place a plurality of carriers C for horizontally accommodating a plurality of substrates (semiconductor wafers W (hereinafter referred to as wafers W) in the present embodiment).

The transport unit 12 is provided adjacent to the carrier placement unit 11, and includes a substrate transport device 13 and a transfer unit 14 therein. The substrate transport apparatus 13 has a wafer holding mechanism for holding the wafer W. The substrate transfer device 13 is movable in the horizontal direction and the vertical direction and rotatable about the vertical axis, and transfers the wafer W between the carrier C and the delivery portion 14 using the wafer holding mechanism.

The processing station 3 is disposed adjacent to the conveying section 12. The processing station 3 includes a conveying section 15 and a plurality of processing units 16 (an example of a processing section). The plurality of processing units 16 are arranged side by side on both sides of the conveying section 15.

The conveying section 15 is internally provided with a substrate conveying device 17. The substrate transport apparatus 17 has a wafer holding mechanism for holding the wafer W. The substrate transfer device 17 is movable in the horizontal direction and the vertical direction and rotatable about the vertical axis, and transfers the wafer W between the delivery unit 14 and the processing unit 16 using the wafer holding mechanism.

The processing unit 16 performs a predetermined substrate processing on the wafer W conveyed by the substrate conveyor 17. The treatment unit 16 is connected to a dissolving section 70 for dissolving an inert gas in an alkaline aqueous solution L (an example of an alkaline treatment liquid) and supplying the solution to the treatment unit 16. An example of the structure of the processing unit 16 and the dissolving section 70 will be described later.

In addition, 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.

The storage unit 19 stores a program for controlling various processes executed in the substrate processing system 1. The storage unit 19 is implemented 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.

The control unit 18 reads and executes the program stored in the storage unit 19 to control the operation of the substrate processing system 1. The program may be a program stored in a computer-readable storage medium, and the program may be loaded from the storage medium into the storage unit 19 of the control device 4. Examples of the computer-readable storage medium include a Hard Disk (HD), a Flexible Disk (FD), an optical disk (CD), a magneto-optical disk (MO), and a memory card.

In the substrate processing system 1 configured as described above, first, the substrate transport apparatus 13 of the carry-in/out 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 delivery unit 14. The wafer W placed on the delivery portion 14 is taken out of the delivery portion 14 by the substrate transfer device 17 of the processing station 3 and is carried into the processing unit 16.

The wafer W sent into the processing unit 16 is processed by the processing unit 16, and then sent out from the processing unit 16 by the substrate transfer device 17 to be placed on the delivery part 14. Then, the processed wafer W placed on the delivery portion 14 is returned to the carrier C of the carrier placement portion 11 by the substrate transport apparatus 13.

< treatment Unit and mixing section >

Next, the processing unit 16 and the dissolving section 70 will be described with reference to fig. 2. Fig. 2 is a schematic diagram showing the structures of the treatment unit 16 and the dissolution part 70 of 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 portion 40, and a recovery cup 50.

The chamber 20 houses the substrate holding mechanism 30, the processing fluid supply unit 40, and the recovery cup 50. A FFU (Fan Filter Unit) 21 is provided at the top of the chamber 20. FFU21 forms a down flow (downflow) within chamber 20.

The substrate holding mechanism 30 includes a holding portion 31, a column portion 32, and a driving portion 33. The holding portion 31 holds the wafer W horizontally. The support column portion 32 is a member extending in the vertical direction, and has a base end portion rotatably supported by the driving portion 33 and a distal end portion horizontally supporting the holding portion 31. The driving unit 33 rotates the column portion 32 about the vertical axis.

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

The processing fluid supply unit 40 supplies a processing fluid to the wafer W. Also, the treatment fluid supply part 40 is connected to the dissolution part 70.

The recovery cup 50 is disposed so as to surround the holding portion 31, and collects the processing liquid scattered from the wafer W by the rotation of the holding portion 31. A liquid discharge port 51 is formed in the bottom of the collection cup 50, and the processing liquid collected in the collection cup 50 is discharged from the liquid discharge port 51 to the outside of the processing unit 16. Further, an exhaust port 52 for exhausting the gas supplied from FFU21 to the outside of processing unit 16 is formed in the bottom of collection cup 50.

The dissolving section 70 includes a chemical liquid storage tank 71, a circulation line 72, a pump 73, a temperature regulator 74, and a bubbling line 75.

An alkaline aqueous solution (an example of an alkaline treatment liquid) L used as an etching liquid is stored in the chemical liquid storage container 71. The basic aqueous solution L includes, for example, at least one of TMAH (TetraMethylAmmonium Hydroxide), an aqueous choline solution, an aqueous KOH (potassium Hydroxide) solution, and aqueous ammonia.

A circulation line 72 for circulating the stored alkaline aqueous solution L is connected to the chemical solution storage tank 71. The circulation line 72 is connected to the above-described treatment fluid supply portion 40.

A pump 73 and a temperature regulator 74 are provided in the circulation line 72. The alkaline aqueous solution L adjusted to a predetermined temperature by the temperature adjuster 74 is circulated through the circulation line 72 by the pump 73. The predetermined temperature is a predetermined temperature, for example, about 25 ℃. The predetermined temperature may be higher than 25 ℃ or may be about 80 ℃.

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

Further, a bubbling line 75 for bubbling the stored alkaline aqueous solution L by adding an inert gas is connected to the chemical solution storage container 71. The inert gas is, for example, nitrogen.

A valve 76 and a flow 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 tank 71 via a valve 76 and a flow rate regulator 77.

The inert gas supplied from the bubbling line 75 is dissolved in the alkaline aqueous solution L. That is, the dissolving section 70 dissolves the inert gas in the alkaline aqueous solution L. The alkaline aqueous solution L has a reduced oxygen concentration due to the dissolution of the inert gas.

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.

As shown in fig. 3, a holding member 311 for holding the wafer W from the side surface 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 separated from the upper surface of the holding portion 31. The wafer W is held by the holding portion 31 with the surface to be etched facing upward.

The processing fluid supply unit 40 includes a plurality of (4 in this case) nozzles 41a to 41d, an arm 42 horizontally supporting the nozzles 41a to 41d, and a rotation/elevation mechanism 43 for rotating and elevating the arm 42.

The nozzle 41a is connected to the dissolving section 70 described above via a valve 44a and a flow regulator 45 a. The nozzle 41b is connected to a DIW supply source 46b via a valve 44b and a flow regulator 45 b. DIW (Delionized Water: DeIonized Water) is used, for example, for the rinsing treatment.

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

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

The processing unit 16 (an example of a processing unit) supplies an alkaline aqueous solution L (an alkaline processing solution) containing an inert gas to the 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 the 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 the inert gas is formed to a predetermined thickness (a predetermined thickness). Details of the etching process will be described later.

< substrate treatment >

Next, the etching liquid generation process according to the first embodiment will be described with reference to the flowchart of fig. 4. Fig. 4 is a flowchart illustrating an etching liquid generation process according to the first embodiment.

The control device 4 performs temperature adjustment processing (S100). The control device 4 drives the pump 73 to circulate the aqueous alkaline solution L through the circulation line 72. The controller 4 also adjusts the temperature of the alkaline aqueous solution L to a predetermined temperature by the temperature adjuster 74.

The control device 4 performs the dissolving process (S101). The control device 4 supplies an inert gas to the alkaline aqueous solution L (an example of an alkaline treatment solution). Specifically, the controller 4 supplies an inert gas from the bubbling line 75 to the alkaline aqueous solution L in the chemical solution storage container 71 to dissolve the inert gas in the alkaline aqueous solution L, thereby lowering the oxygen concentration of the alkaline aqueous solution L. The controller 4 measures the oxygen concentration of the alkaline aqueous solution L circulating through the circulation line 72 with the sensor 79, and supplies the 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 predetermined concentration, specifically, 0.1 ppm. That is, the oxygen concentration of the alkaline aqueous solution L is 0.1ppm or less.

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

Next, the substrate processing of the first embodiment will be described with reference to the flowchart of fig. 5. Fig. 5 is a flowchart illustrating substrate processing of the first embodiment.

The controller 4 performs the loading process (S200), and the controller 4 loads the wafer W into the chamber 20 of the processing unit 16 by the substrate transfer unit 17. The wafer W is held by the holding member 311 in a state where the surface to be subjected to the etching process is directed upward. Thereafter, the controller 4 controls the driving unit 33 to rotate the substrate holding mechanism 30. That is, the controller 4 rotates the wafer W.

The controller 4 performs an oxide film removal process (S201). The controller 4 moves the nozzle 41c of the processing fluid supplier 40 to a position above the center of the wafer W. The controller 4 supplies DHF as an etching solution to the front surface of the wafer W from the nozzle 41 c.

The DHF supplied to the front surface of the wafer W is diffused over the entire front surface of the wafer W by a centrifugal force accompanying the rotation of the wafer W. Thereby, the native oxide film formed on the wafer W is removed by the DHF.

The control device 4 performs the first flushing process (S202). The controller 4 moves the nozzle 41b of the processing fluid supplier 40 to a position above the center of the wafer W. The controller 4 supplies DIW from the nozzle 41b to the front surface of the wafer W. The DIW supplied to the front surface of the wafer W replaces the DHF remaining on the front surface of the wafer W.

The controller 4 performs an etching process (S203). The controller 4 supplies the wafer W with the alkaline aqueous solution L having the oxygen concentration reduced on the surface of the wafer W, and etches the wafer W with the alkaline aqueous solution L.

The controller 4 first diffuses 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 controller 4 moves the nozzle 41a of the processing fluid supplier 40 to a position above the center of the wafer W. Then, the controller 4 supplies the alkaline aqueous solution L from the nozzle 41a to the front surface of the wafer W at a first predetermined flow rate, and rotates the wafer W at a first predetermined rotation speed. The first predetermined flow rate is a preset flow rate, and is, for example, 1.5L/min. The first predetermined rotation speed is a preset rotation speed, and is set to a rotation speed of 500rpm or more, for example. The first predetermined rotation speed in the present embodiment is, for example, 1000 rpm.

The alkaline aqueous solution L supplied to the surface of the wafer W is diffused over the entire surface of the wafer W by a centrifugal force accompanying the rotation of the wafer W. The time for rotating the wafer W at the first predetermined rotation speed may be a time for diffusing the alkaline aqueous solution L over the entire surface of the wafer W, and may be a short time such as 2 seconds.

The controller 4 then 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 controller 4 rotates the wafer W at the second predetermined rotation speed. The predetermined thickness is a predetermined thickness, and is, for example, 400 μm or more. The second predetermined rotation speed is a preset rotation speed and is smaller than the first predetermined rotation speed. The second predetermined rotation speed is set to a rotation speed lower than 500rpm, for example. The second predetermined rotation speed in the present embodiment is set to be greater than 0rpm and 30rpm or less, for example.

The controller 4 etches the wafer W by supplying the alkaline aqueous solution L from the nozzle 41a while rotating the wafer W in a state where a liquid film of the alkaline aqueous solution L having a predetermined thickness or more is formed.

The control device 4 performs the second flushing process (S204). The controller 4 supplies DIW to the front surface of the wafer W in the same manner as the first rinsing process.

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

The controller 4 performs the drying process (S205), and the controller 4 moves the nozzle 41d of the processing fluid supply unit 40 to the center of the wafer W. The controller 4 rotates the substrate holding mechanism 30 at a predetermined rotation speed and supplies IPA from the nozzle 41d to the front surface of the wafer W. After supplying IPA for a predetermined time, the controller 4 stops supplying IPA and rotates and dries the wafer W.

By supplying IPA to the front surface of the wafer W, the DIW remaining on the front surface of the wafer W is replaced with IPA. Further, the controller 4 may spin-dry the wafer W without supplying IPA.

The control device 4 performs the sending-out process (S206). After controlling the drive unit 33 to stop the rotation of the wafer W, the controller 4 controls the substrate transfer unit 17 to transfer the wafer W from the processing unit 16. When the sending-out process is completed, a series of substrate processes for one wafer W is completed.

It is known that when the etching treatment is performed using the alkaline aqueous solution L, oxygen contained in the alkaline aqueous solution L is adsorbed to the wafer W to form the oxide film F.

Here, a comparative example in which the substrate treatment of the first embodiment is not performed will be described. In the substrate treatment of the comparative example, the oxygen concentration of the alkaline aqueous solution L was not lowered, and the thickness of the liquid film of the alkaline aqueous solution L was not maintained at a predetermined thickness or more. In addition, a downward flow is formed by FFU21 in chamber 20, oxygen dissolves from the surface of the liquid film of alkaline aqueous solution L, and the oxygen concentration becomes high in the vicinity of the surface of the liquid film of alkaline aqueous solution L.

Therefore, in the substrate treatment of the comparative example, oxygen adsorption increases in the vicinity of the openings of the holes H in the wafer W, and the oxide film F formed becomes thick as shown in fig. 6A. Fig. 6A is a schematic view of a hole H of a wafer W in the substrate processing of the comparative example.

In the substrate treatment of the comparative example, oxygen is adsorbed in the vicinity of the opening of the hole H of the wafer W, and the oxygen concentration of the alkaline aqueous solution L is lower on the bottom side of the hole H of the wafer W than in the vicinity of the opening. Thus, the thickness of the oxide film F formed on the bottom side of the hole H in the wafer W becomes thinner than that on the opening side, and 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 large. Therefore, in the substrate treatment of the comparative example, the etching ratio obtained by dividing the etching amount of the bottom portion of the hole H by the etching amount of the opening portion of the hole H becomes large.

In contrast, in the substrate treatment of the first embodiment, etching is performed with the alkaline aqueous solution L in which the oxygen concentration is reduced by dissolution with an inert gas. Therefore, in the substrate treatment according to the first embodiment, the adsorption of oxygen in the vicinity of the opening of the hole H in the wafer W can be suppressed.

In addition, the wafer W is rotated while the alkaline aqueous solution L is supplied 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, thereby performing etching. Thus, in the substrate treatment of the first embodiment, when oxygen is dissolved from the surface of the liquid film of the alkaline aqueous solution L, the distance between the oxygen in the vicinity of the surface of the liquid film of the alkaline aqueous solution L and the opening of the hole H of the wafer W becomes longer. Therefore, in the substrate treatment according to the first embodiment, the adsorption of oxygen in the vicinity of the opening of the hole H in the wafer W can be suppressed.

In the substrate processing according to the first embodiment, as shown in fig. 6B, the oxide film F can be prevented from being formed in the vicinity of the opening of the hole H in the wafer W. Therefore, in the substrate treatment according to the first embodiment, 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 is reduced. Therefore, in the substrate processing of the first embodiment, the etching ratio becomes small. Fig. 6B is a schematic view of the hole H of the wafer W in the substrate processing of the first embodiment.

Fig. 7 shows simulation results of the oxygen concentration and the etching ratio of the opening of the hole H in the wafer W. Fig. 7 is a simulation result in the substrate processing of the first embodiment. Fig. 7 shows the etching ratio when nitrogen as the active gas is dissolved in the alkaline aqueous solution L and the oxygen concentration of the alkaline aqueous solution L is changed. In the simulation shown in fig. 7, the rotation speed of the wafer W was 30 rpm.

As shown in fig. 7, when the oxygen concentration at the opening of the hole H of the wafer W becomes low, the etching ratio approaches "1". When the oxygen concentration of the alkaline aqueous solution L is 0.1ppm or less, the etching ratio is small, and the uniformity of the etching amount on the bottom side of the hole H 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.

In the substrate treatment according to the first embodiment, the etching treatment is performed after the alkaline aqueous solution L is diffused over the entire surface of the wafer W, with the rotation speed of the substrate set to 30 rpm.

Here, fig. 8 shows the relationship between the rotation speed of the wafer W and the etching amount. Fig. 8 is a graph showing a relationship between the number of rotations of the wafer W and the etching amount in the substrate treatment according to the first embodiment. Fig. 8 shows the etching amounts when the number of revolutions of the wafer W is set to 1000rpm, 500rpm, and 200 rpm.

As shown in fig. 8, when the rotation speed of the wafer W is reduced, the difference in the etching amount corresponding to the distance from the center of the wafer W can be reduced. That is, when the rotation speed of the wafer W is reduced, the uniformity of the etching amount in the radial direction of the wafer W, that is, the in-plane uniformity can be improved.

As described above, the substrate processing method of the first embodiment includes the forming process and the processing process. In the forming step, an alkaline aqueous solution L (an example of an alkaline treatment solution) having a reduced oxygen concentration is supplied to the wafer W (an example of a substrate) to form a liquid film of the alkaline aqueous solution L on the wafer W. In the treatment step, the wafer W is etched by supplying the alkaline aqueous solution L while rotating the wafer W in a state where a liquid film having a predetermined thickness (predetermined thickness) is formed on the wafer W. Specifically, the oxygen concentration of the alkaline aqueous solution L is 0.1ppm or less.

This can prevent the oxide film F from being formed in the vicinity of 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.

In the forming step, the wafer W is rotated at the first rotation speed. In the processing step, the wafer W is rotated at a second rotation speed lower than the first rotation speed.

Thereby, a liquid film of the alkaline aqueous solution L is formed quickly on the entire wafer W, and oxygen can be prevented from reaching the inside of the hole H. Further, a liquid film of the alkaline aqueous solution L having a predetermined thickness or more can be formed on the wafer W, and the formation of the oxide film F in the vicinity of 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 fluctuation of the liquid surface of the alkaline aqueous solution L can be suppressed, and the oxygen can be suppressed from being mixed into the alkaline aqueous solution L.

In addition, the substrate processing method includes a dissolving step. In the dissolving step, the inert gas is dissolved in the alkaline aqueous solution L.

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.

In addition, the substrate processing method includes a replacement step. In the replacement step, the alkaline aqueous solution L of the wafer W subjected to the etching treatment is replaced with DIW (an example of a rinse solution). This can end the etching process of the wafer W.

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

Thus, the processing unit 16 can suppress the formation of the oxide film F in the vicinity of 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.

(second embodiment)

Next, a substrate processing system 1 according to a second embodiment will be described. Here, differences from the substrate processing system 1 of 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 is omitted.

< processing Unit >

As shown in fig. 9, the process unit 16 according to the second embodiment includes a release portion 100 for releasing an inert gas to 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.

The discharge unit 100 includes a nozzle 101, an arm 102 supporting the nozzle 101, and a rotation mechanism 103 for rotating the arm 102. The rotation mechanism 103 may also raise and lower the arm 102.

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. 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 from the nozzle 101 to the wafer W may be supplied from the same inert gas supply source.

< substrate treatment >

Next, the substrate processing of the second embodiment is explained. In addition, the entire flow of the substrate processing of the second embodiment is the same as the substrate processing of the first embodiment shown in fig. 5.

The controller 4 releases the inert gas from the release portion 100 and supplies the alkaline aqueous solution L when the alkaline aqueous solution L is diffused over the entire surface of the wafer W in the etching process (fig. 5, S203). For example, the controller 4 supplies the alkaline aqueous solution L from the nozzle 41a after the inert gas is released from the release portion 100 onto the surface of the wafer W, and diffuses the alkaline aqueous solution L over the entire surface of the wafer W.

By releasing the inert gas from the release section 100 toward the wafer W, a layer of the inert gas 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 can be reduced.

The inert gas released from the release section 100 to the surface of the wafer W may be released in the entire etching process. The controller 4 also releases the inert gas from the release portion 100 to the wafer W when the alkaline aqueous solution L is supplied from the nozzle 41a at the first predetermined flow rate to the front surface of the wafer W. The controller 4 supplies an inert gas to the wafer W (an example of a substrate) at least before the wafer W forms a liquid film of the alkaline aqueous solution L.

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 formation step.

This can suppress the dissolution of oxygen into 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 in the vicinity of 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.

(third embodiment)

Next, a substrate processing system 1 according to a third embodiment is explained. Here, differences from the substrate processing system 1 of 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 is omitted.

< processing Unit >

As shown in fig. 10, the treatment unit 16 according to the third embodiment has a nozzle 41a for discharging the aqueous alkali solution L supported by an arm 110. Fig. 10 is a schematic diagram showing the structure of the processing unit 16 according to the third embodiment.

The arm 110 is rotated and lifted by the rotary lifting mechanism 111. That is, in the treatment unit 16, the nozzle 41b for discharging the DIW, the nozzle 41c for discharging the DHF, and the nozzle 41a for discharging the alkaline aqueous solution L are supported by the different arms 42 and 110.

< substrate treatment >

Next, the etching process of the third embodiment is explained. In addition, the entire flow of the substrate processing of the third embodiment is the same as the substrate processing of the first embodiment shown in fig. 5.

In the etching process, the controller 4, as shown in fig. 5, S203), 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. The controller 4 also arranges the nozzle 41b above the center of the wafer W to supply DIW to the center of the wafer W.

That is, the controller 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. The controller 4 rotates the wafer W at a second predetermined rotational speed to supply the DIW and the alkaline aqueous solution L to the wafer W. The second predetermined rotation speed is set to a rotation speed lower than 500rpm as described above, for example, to a rotation speed of 200rpm or less. The controller 4 supplies the DIW and the alkaline aqueous solution L for a predetermined time. The predetermined time is a predetermined time, and is, for example, 120 seconds.

After that, the controller 4 stops the supply of the alkaline aqueous solution L and continues the supply of the DIW. Thereby, the alkaline aqueous solution L in the outer peripheral portion of the wafer W is replaced with DIW.

When the replacement with the DIW is completed, the controller 4 stops the supply of the DIW and arranges the nozzle 41a at the center of the wafer W. Then, the controller 4 supplies the alkaline aqueous solution L from the nozzle 41a to the surface of the wafer W, replaces the DIW with the alkaline aqueous solution L, and diffuses the alkaline aqueous solution L over the entire surface of the wafer W. That is, the processing unit 16 (an example of a processing portion) supplies the alkaline aqueous solution L (an example of an alkaline processing 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.

Then, the controller 4 supplies the alkaline aqueous solution L from the nozzle 41a to the front surface of the wafer W at a first predetermined flow rate and rotates the wafer W at a second predetermined rotation speed, as in the first embodiment. The second predetermined rotation speed is set to a rotation speed lower than, for example, 500rpm as in the first embodiment. The second predetermined rotation speed is set to be greater than 0rpm and not greater than 30rpm, for example.

In the forming step of the substrate processing method according to the third embodiment, the alkaline aqueous solution L (an example of an alkaline processing 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. Thus, the outer peripheral portion of the wafer W is etched in advance before the alkaline aqueous solution L is supplied to the central portion of the wafer W. Therefore, when the etching treatment is performed by supplying the alkaline aqueous solution L to the central portion of the wafer W, the in-plane uniformity of the wafer W can be improved.

(fourth embodiment)

Next, a substrate processing system 1 according to a fourth embodiment is explained. Here, differences from the substrate processing system 1 of 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 is omitted.

< processing Unit >

The processing unit 16 of the fourth embodiment is provided with a weir mechanism 120 as shown in fig. 11. 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.

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

The support portion 122 supports the bank portion 121. 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 bank portion 121 and the first support member 122 a.

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

The moving mechanism 124 moves the column portion 123 in the vertical direction. That is, the moving mechanism 124 vertically moves the support portion 122 and the weir portion 121 via the support portion 123. Specifically, the moving mechanism 124 moves the bank 121 between the evacuation position and the blocking position. The escape position is a position at which the upper end surface of the dam portion 121 is lower than the upper surface of the wafer W. The dam position is a position where the upper end surface of the dam portion 121 is higher than the upper surface of the wafer W. For example, the dam position is a position 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.

In the dam mechanism 120, the dam portion 121 serves as a blocking position during the etching process, and the alkaline aqueous solution L is blocked on the wafer W by the dam portion 121.

As described above, the processing unit 16 (an example of a processing unit) supplies the wafer W with the alkaline aqueous solution L (an example of an alkaline processing liquid) containing the inert gas while surrounding the outer periphery of the wafer W (an example of a substrate) with the dam portion 121.

< substrate treatment >

Next, the substrate processing of the fourth embodiment is explained. In addition, the entire flow of the substrate processing of the fourth embodiment is the same as that of the first embodiment.

The controller 4 moves the weir portion 121 of the weir mechanism 120 from the retreat position to the blocking position during the etching process (fig. 5, S203), and supplies the alkaline aqueous solution L to the wafer W.

The alkaline aqueous solution L is blocked by the dam portion 121, and a liquid film having a predetermined thickness or more is formed on the surface of the wafer W. Although a part of the aqueous alkali solution L leaks downward from the gap formed between the weir portion 121 and the holding portion 31, the flow rate of the aqueous alkali solution L supplied from the nozzle 41a is larger than the flow rate of the aqueous alkali solution L leaking from the gap. Therefore, a liquid film having a predetermined thickness or more is formed on the surface of the wafer W.

The controller 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 controller 4 also supplies the alkaline aqueous solution L from the nozzle 41a while rotating the arm 42 supporting the nozzle 41 a.

As described above, the alkaline aqueous solution L is supplied to maintain the thickness of the liquid film formed on the wafer W by the alkaline aqueous solution L at a predetermined thickness or more, and the etching process is performed. The aqueous alkaline solution L is dammed up by the weir portion 121 and supplied from the nozzle 41a, and thus overflows from the weir portion 121.

In the treatment step of the substrate treatment method according to 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.

This makes it possible to keep the thickness of the liquid film of the alkaline aqueous solution L at a predetermined thickness or more by the bank 121 and to allow the oxygen-containing alkaline aqueous solution L existing in the vicinity of the liquid surface of the liquid film of the alkaline aqueous solution L to overflow from the bank 121. Therefore, the oxide film F can be prevented from being formed in the vicinity of the opening of the hole H in the wafer W, and the difference in 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.

(modification example)

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

Specifically, the controller 4 of the modification rotates the wafer W at a first predetermined rotational speed during the etching process, and switches the flow rate of the alkaline aqueous solution L supplied from the nozzle 41a to the front 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 a flow rate smaller than the first predetermined flow rate. For example, the second predetermined flow rate is 0.5L/min. The controller 4 of the modification 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.

The variable flow rate may be 3 or more flow rates. Further, the flow rate can be continuously changed.

As described above, in the treatment step of the modification, the flow rate (an example of the supply flow rate) of the alkaline aqueous solution L (an example of the alkaline treatment liquid) is changed. This improves the fluidity of the alkaline aqueous solution in the holes H of the wafer W, and improves the replaceability of the alkaline aqueous solution in the holes H of the wafer W. Therefore, the wafer W can be etched quickly.

The substrate processing system 1 according to the above-described embodiment and the modified examples may be used in combination. For example, the substrate processing system 1 may block the aqueous alkali solution L with the weir portion 121 and supply the inactive gas to the wafer W with the dechucking portion 100. In the substrate processing system 1, the flow rate of the alkaline aqueous solution L supplied from the nozzle 41a may be changed by supplying the inert gas to the wafer W through the release portion 100.

Furthermore, the disclosed embodiments of the invention are illustrative in all respects and should not be considered restrictive. In fact, the above embodiments can be embodied in various ways. In addition, the above-described embodiments may be omitted, replaced, and changed in various ways without departing from the scope of claims of the present invention and the idea thereof.