CN114242614A

CN114242614A - Substrate processing method and substrate processing apparatus

Info

Publication number: CN114242614A
Application number: CN202111059078.7A
Authority: CN
Inventors: 佐佐木光敏; 高桥朋宏; 佐藤昌治; 杉冈真治
Original assignee: Screen Holdings Co Ltd
Current assignee: Screen Holdings Co Ltd
Priority date: 2020-09-09
Filing date: 2021-09-09
Publication date: 2022-03-25
Also published as: KR20220033429A; KR102670179B1

Abstract

The invention provides a substrate processing method and a substrate processing apparatus capable of processing a substrate into a more complex shape. The substrate processing method is a method of etching a substrate (W) having an oxide film (Ma) and a nitride film (Mb) alternately stacked in a processing bath (3) with an etching solution (E) containing phosphoric acid. In the first processing step (step S2), the parameters are controlled so that the physical quantity corresponding to the concentration of phosphoric acid in the etching solution (E) becomes a first target value. In the second processing step (step S4), the parameters are controlled so that the physical quantity corresponding to the concentration of phosphoric acid in the etching solution (E) becomes a second target value lower than the first target value. The parameter is a parameter for varying a physical quantity corresponding to the concentration of phosphoric acid in the etching solution (E). The second target value indicates a value at which the etching rate of the nitride film (Mb) is greater and the etching rate of the oxide film (Ma) is less than the first target value.

Description

Substrate processing method and substrate processing apparatus

Technical Field

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

Background

A substrate processing apparatus for etching a substrate having a laminated structure in which an oxide film and a nitride film are alternately laminated is known. For example, patent document 1 discloses a batch-type substrate processing apparatus for etching a substrate with a processing liquid containing phosphoric acid. Specifically, the substrate processing apparatus of patent document 1 removes the nitride film mainly by selectively etching the nitride film out of the oxide film and the nitride film.

Patent document 1: japanese patent laid-open No. 2020 and 47886.

Since the substrate processing apparatus of patent document 1 hardly etches an oxide film, the laminated structure after etching is used for a process of forming a structure in which a plurality of flat oxide films are arranged in a comb shape. However, due to the miniaturization and high integration of semiconductor devices, the substrate needs to be processed into a more complicated shape.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object thereof is to provide a substrate processing method and a substrate processing apparatus capable of processing a substrate into a more complicated shape.

According to an aspect of the present invention, a substrate processing method is a method of etching a substrate having an oxide film and a nitride film alternately stacked with each other in a processing bath with an etching solution containing phosphoric acid. The substrate processing method includes a first processing step and a second processing step. In the first treatment step, a parameter for varying a physical quantity corresponding to the concentration of the phosphoric acid in the etching solution is controlled so that the physical quantity becomes a first target value. In the second processing step, the parameter is controlled so that the physical quantity becomes a second target value lower than the first target value. The second target value represents a target value of the physical quantity in which the etching rate of the nitride film is greater and the etching rate of the oxide film is smaller than the first target value.

In one embodiment, the length of the specific gravity value change period is controlled to indicate the length of a period until the physical quantity changes from the first target value to the second target value in the second processing step.

In one embodiment, in the second processing step, the target value is changed stepwise from the first target value to the second target value, and the length of the specific gravity value change period is controlled.

In one embodiment, the length of the period during which the specific gravity value changes is controlled by adjusting the flow rate of the diluent supplied to the etching solution.

In one embodiment, the amount of moisture evaporated from the etching solution is adjusted to control the length of the period during which the specific gravity value is changed.

In one embodiment, the substrate processing method further includes a step of determining a length of the specific gravity change period based on a size of a device manufactured using the substrate.

In one embodiment, the substrate processing method further includes a step of determining the first target value and the second target value based on a size of a device manufactured using the substrate.

According to another aspect of the present invention, a substrate processing apparatus etches a substrate having an oxide film and a nitride film alternately stacked with an etching solution containing phosphoric acid. The substrate processing apparatus includes a processing bath, a substrate holding unit, a parameter control unit, and a changing unit. The treatment tank stores the etching solution. The substrate holding unit holds the substrate in the etching solution in the processing bath. The parameter control unit controls a parameter for varying a physical quantity corresponding to a concentration of the phosphoric acid in the etching solution so that the physical quantity becomes a target value. The changing unit changes the target value from a first target value to a second target value lower than the first target value during the etching process of the substrate. The second target value represents a target value of the physical quantity in which the etching rate of the nitride film is greater and the etching rate of the oxide film is smaller than the first target value.

According to the substrate processing method and the substrate processing apparatus of the present invention, the substrate can be processed into a more complicated shape.

Drawings

Fig. 1A is a diagram showing a substrate processing apparatus according to embodiment 1 of the present invention, and fig. 1B is a diagram showing a substrate processing apparatus according to embodiment 1 of the present invention.

Fig. 2 is a sectional view showing a configuration of a substrate processing apparatus according to embodiment 1 of the present invention.

Fig. 3 is a diagram showing a configuration of a substrate processing apparatus according to embodiment 1 of the present invention.

Fig. 4 is a diagram showing a substrate before being processed by the substrate processing apparatus according to embodiment 1 of the present invention.

Fig. 5 is a diagram showing an example of a substrate processed by the substrate processing apparatus according to embodiment 1 of the present invention.

Fig. 6 is a diagram showing the structure of the pressure measuring unit.

Fig. 7 is a diagram showing the configuration of the first bubbling portion and the processing tank.

Fig. 8 is a block diagram showing the configuration of the control device.

Fig. 9 is a diagram showing an example of a change in the specific gravity value of phosphoric acid when the etching process is performed by the substrate processing apparatus according to embodiment 1 of the present invention.

Fig. 10 is a flowchart showing a substrate processing method according to embodiment 1 of the present invention.

Fig. 11A is a view showing an example of a substrate processed by the substrate processing apparatus according to embodiment 1 of the present invention, and fig. 11B is a view showing another example of a substrate processed by the substrate processing apparatus according to embodiment 1 of the present invention.

Fig. 12 is a diagram showing an example of a change in the specific gravity value of phosphoric acid when the etching process is performed by the substrate processing apparatus according to embodiment 2 of the present invention.

Fig. 13 is a diagram showing a configuration of a substrate processing apparatus according to embodiment 3 of the present invention.

Fig. 14 is a diagram showing a configuration of a substrate processing apparatus according to embodiment 4 of the present invention.

Fig. 15 is a diagram showing a configuration of a substrate processing apparatus according to embodiment 5 of the present invention.

Fig. 16 is a sectional view showing the structure of a substrate processing apparatus according to embodiment 6 of the present invention.

Fig. 17 is a sectional view showing a configuration of a substrate processing apparatus according to embodiment 7 of the present invention.

Fig. 18 is a diagram showing the structure of the second bubbling portion.

Fig. 19 is a diagram showing a determination table.

Fig. 20 is a flowchart showing a substrate processing method according to embodiment 8 of the present invention.

Fig. 21 is a diagram showing another example 1 of the determination table.

Fig. 22 is a diagram showing another example 2 of the determination table.

Description of reference numerals

3: treatment tank

5: diluent supply pipe

31: inner groove

32: outer trough

100: substrate processing apparatus

110: control device

130: substrate holding part

140: controller

E: etching solution

And Ma: oxide film

Mb: nitride film

SGV: period of change of specific gravity

TV 1: a first target value

TV 2: second target value

W: substrate

Detailed Description

Embodiments of a substrate processing method and a substrate processing apparatus according to the present invention will be described below with reference to the drawings (fig. 1 to 22). However, the present invention is not limited to the following embodiments. Note that, for portions overlapping in description, the description may be appropriately omitted. In the drawings, the same or corresponding portions are denoted by the same reference numerals and description thereof will not be repeated.

In the present specification, for the sake of easy understanding, the X direction, the Y direction, and the Z direction orthogonal to each other are described. Generally, the X and Y directions are parallel to the horizontal direction, and the Z direction is parallel to the vertical direction. However, the orientation when the substrate processing method of the present invention is performed and the orientation when the substrate processing apparatus of the present invention is used are not intended to be limited by the definition of these directions.

The "substrate" in the embodiment of the present invention can be applied to various substrates such as a semiconductor wafer, a glass substrate for photomask, a glass substrate for liquid crystal Display, a glass substrate for plasma Display, a substrate for FED (Field Emission Display), a substrate for optical disk, a substrate for magnetic disk, and a substrate for optical disk. Hereinafter, embodiments of the present invention will be described mainly by way of examples of a substrate processing method and a substrate processing apparatus used for processing a disc-shaped semiconductor wafer, and the present invention can be similarly applied to processing of various substrates as described above. In addition, substrates of various shapes can be applied.

[ embodiment 1]

Embodiment 1 of the present invention will be described below with reference to fig. 1 to 11. First, the substrate processing apparatus 100 according to the present embodiment will be described with reference to fig. 1A and 1B. The substrate processing apparatus 100 of the present embodiment is of a batch type. Therefore, the substrate processing apparatus 100 processes a plurality of substrates W at once. Specifically, the substrate processing apparatus 100 performs etching processing on a plurality of substrates W in a batch unit. For example, 1 lot is composed of 25 substrates W.

Fig. 1A and 1B are diagrams illustrating a substrate processing apparatus 100 according to the present embodiment. Specifically, fig. 1A shows the substrate processing apparatus 100 before the substrate W is loaded into the processing bath 3. Fig. 1B shows the substrate processing apparatus 100 after the substrate W is loaded into the processing bath 3. As shown in fig. 1A and 1B, the substrate processing apparatus 100 includes a processing bath 3, a control device 110, an elevating unit 120, and a substrate holding unit 130.

The processing bath 3 stores an etching solution E. The etching solution E contains phosphoric acid (H)₃PO₄). The etching solution E may contain phosphoric acid and a diluent. For example, the diluent isDIW (Deionized Water: Deionized Water). DIW is one kind of pure water. For example, the diluent may be carbonated water, electrolytic ionized water, hydrogen water, ozone water, or hydrochloric acid water having a diluted concentration (for example, about 10ppm to about 100 ppm). The etching solution E may further contain an additive.

The etching solution E is heated. For example, the temperature of the etching solution E is 120 ℃ to 160 ℃. Therefore, the moisture contained in the etching solution E evaporates. The diluent is appropriately supplied to the etching solution E so that the physical quantity corresponding to the concentration of phosphoric acid in the etching solution E is maintained at a target value. Here, the physical quantity corresponding to the concentration of the phosphoric acid in the etching liquid E indicates, for example, a concentration value of the phosphoric acid in the etching liquid E or a specific gravity value of the phosphoric acid in the etching liquid E. In the following description, the physical amount corresponding to the concentration of phosphoric acid in the etching liquid E may be referred to as "physical amount corresponding to the concentration of phosphoric acid".

The processing bath 3 has an inner bath 31 and an outer bath 32. The outer groove 32 surrounds the inner groove 31. In other words, the processing bath 3 has a double bath structure. Each of the inner tank 31 and the outer tank 32 has an upper opening that opens upward.

The inner tank 31 and the outer tank 32 both store the etching solution E. The inner tank 31 accommodates a plurality of substrates W. Specifically, the plurality of substrates W held by the substrate holding portion 130 are accommodated in the inner tank 31. The plurality of substrates W are stored in the inner tank 31, and are immersed in the etching liquid E in the inner tank 31.

The substrate holding unit 130 holds a plurality of substrates W in the etching solution E in the processing bath 3 (inner bath 31). Specifically, the substrate holding portion 130 includes a plurality of holding rods 131 and a main body plate 132. The main body plate 132 is a plate-shaped member and extends in the vertical direction (Z direction). The plurality of holding bars 131 extend in the horizontal direction (Y direction) from one main surface of the main body plate 132. In the present embodiment, the substrate holding portion 130 includes three holding rods 131 (see fig. 2).

The plurality of substrates W are held by the plurality of holding rods 131. Specifically, the lower edge of each substrate W is brought into contact with the plurality of holding rods 131, whereby the plurality of substrates W are held in an upright posture (vertical posture) by the plurality of holding rods 131. More specifically, the plurality of substrates W held by the substrate holding portion 130 are arranged at intervals in the Y direction. That is, the plurality of substrates W are aligned in a row in the Y direction. The plurality of substrates W are held by the substrate holding portion 130 in a posture substantially parallel to the XZ plane.

The control device 110 controls the operations of the respective parts of the substrate processing apparatus 100. For example, the control device 110 controls the operation of the elevating unit 120. The controller 110 controls the elevating unit 120 to elevate and lower the substrate holding unit 130. The elevating unit 120 elevates the substrate holding unit 130 to move the substrate holding unit 130 vertically upward or vertically downward while holding a plurality of substrates W. The elevating unit 120 has a driving source and an elevating mechanism, and the elevating mechanism is driven by the driving source to elevate and lower the substrate holding unit 130. For example, the drive source includes a motor. For example, the elevating mechanism includes a rack/pinion mechanism or a ball screw.

More specifically, the elevating unit 120 elevates the substrate holding unit 130 between a processing position (position shown in fig. 1B) and a retracted position (position shown in fig. 1A). As shown in fig. 1B, when the substrate holding portion 130 moves down vertically downward (Z direction) to a processing position while holding a plurality of substrates W, the plurality of substrates W are loaded into the processing bath 3. Specifically, the plurality of substrates W held by the substrate holding portion 130 are moved into the inner tank 31. As a result, the plurality of substrates W are immersed in the etching liquid E in the inner tank 31, and the plurality of substrates W are etched by the etching liquid E. On the other hand, as shown in fig. 1A, when the substrate holding portion 130 moves to the retracted position, the plurality of substrates W held by the substrate holding portion 130 move to above the processing bath 3, and the plurality of substrates W are pulled up from the etching solution E.

Next, the structure of the substrate processing apparatus 100 according to the present embodiment will be described with reference to fig. 2. Fig. 2 is a sectional view showing the structure of the substrate processing apparatus 100 according to the present embodiment. As shown in fig. 2, the control device 110 includes a control unit 111 and a storage unit 112.

The control unit 111 has a processor. For example, the control Unit 111 includes a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). Alternatively, the control unit 111 may have a general-purpose arithmetic unit. The control unit 111 controls the operations of the respective units of the substrate processing apparatus 100 based on the computer program and data stored in the storage unit 112.

The storage unit 112 stores data and computer programs. The data comprises protocol data. The protocol data includes information representing a plurality of protocols. The plurality of protocols define the processing contents and the processing steps of the substrate W. The data also includes data indicating a target value of the physical quantity corresponding to the concentration of phosphoric acid. The storage unit 112 has a main storage device. The main storage device is, for example, a semiconductor memory. The storage part 112 may also have an auxiliary storage device. For example, the secondary storage device includes at least one of a semiconductor memory and a hard disk drive. The storage portion 112 may contain removable media.

The structure of the substrate processing apparatus 100 according to the present embodiment will be further described with reference to fig. 2. As shown in fig. 2, the substrate processing apparatus 100 further includes a phosphoric acid supply tube 4, a diluent supply tube 5, a pressure measuring unit 6, a first bubbling unit 7, an etching liquid circulating unit 8, and an automatic cover 21.

The automatic lid 21 opens and closes the upper opening of the processing bath 3. In other words, the automatic lid 21 opens and closes the upper opening of the inner tank 31 and the upper opening of the outer tank 32. In the present embodiment, the automatic cover 21 has a first cover sheet 22 and a second cover sheet 23. The first lid plate 22 is openable and closable with respect to the upper opening of the processing bath 3. The second lid plate 23 is openable and closable with respect to the upper opening of the processing bath 3. The automatic lid 21 is openable and closable in a left-right split manner by opening and closing the first lid piece 22 and the second lid piece 23.

Specifically, the first lid sheet 22 is rotatable about the first rotation axis P1. The first rotation axis P1 extends in the Y direction. The first rotation axis P1 supports the end of the first lid sheet 22 on the side opposite to the center side of the automatic lid 21. The second lid sheet 23 is freely rotatable about the second rotation axis P2. The second rotation axis P2 extends in the Y direction. The second rotation axis P2 supports the end of the second lid sheet 23 on the side opposite to the center side of the automatic lid 21.

The control device 110 (control unit 111) opens the automatic lid 21 when the substrate holding unit 130 is moved from the retracted position (position shown in fig. 1A) to the processing position (position shown in fig. 1B). By opening the robot cover 21, the upper opening of the processing bath 3 is opened, and the substrate W can be loaded into the processing bath 3 (inner bath 31). The control device 110 (control unit 111) closes the automatic lid 21 during the etching process of the substrate W. By closing the automatic lid 21, the upper opening of the processing bath 3 is closed. As a result, the inside of the treatment tank 3 becomes a closed space.

The control device 110 (control unit 111) opens the automatic cover 21 when the substrate holding unit 130 is moved from the processing position (position shown in fig. 1B) to the retracted position (position shown in fig. 1A). By opening the robot cover 21, the upper opening of the processing bath 3 is opened, and the substrate W can be pulled up from the processing bath 3 (inner bath 31).

Next, the phosphoric acid supply pipe 4 and the diluent supply pipe 5 will be described with reference to fig. 2.

The phosphoric acid supply pipe 4 supplies phosphoric acid to the processing bath 3. In the present embodiment, the phosphoric acid supply pipe 4 supplies phosphoric acid to the outer tank 32. Specifically, the phosphoric acid supply pipe 4 includes a phosphoric acid supply nozzle 41, a phosphoric acid supply pipe 42, and an opening/closing valve 43.

The phosphoric acid supply nozzle 41 is disposed above the processing bath 3. The phosphoric acid supply nozzle 41 is a hollow tubular member. A plurality of discharge holes are formed in the phosphoric acid supply nozzle 41. In the present embodiment, the phosphoric acid supply nozzle 41 extends in the Y direction. The plural discharge holes of the phosphoric acid supply nozzle 41 are formed at equal intervals in the Y direction.

The phosphoric acid supply pipe 42 supplies phosphoric acid to the phosphoric acid supply nozzle 41. When phosphoric acid is supplied to the phosphoric acid supply nozzle 41 through the phosphoric acid supply pipe 42, phosphoric acid is discharged from the plurality of discharge holes of the phosphoric acid supply nozzle 41 to the outer tank 32. As a result, phosphoric acid is supplied to the outer tank 32.

An opening/closing valve 43 is attached to the phosphoric acid supply pipe 42. The opening and closing valve 43 is, for example, an electromagnetic valve. The opening/closing valve 43 is controlled by the control device 110 (control unit 111).

The opening/closing valve 43 opens and closes the flow path of the phosphoric acid supply pipe 42 to control the flow of phosphoric acid flowing through the phosphoric acid supply pipe 42. Specifically, when the opening/closing valve 43 is opened, phosphoric acid flows to the phosphoric acid supply nozzle 41 through the phosphoric acid supply pipe 42. As a result, phosphoric acid is discharged from the phosphoric acid supply nozzle 41. On the other hand, when the open/close valve 43 is closed, the flow of phosphoric acid is cut off, and the phosphoric acid supply nozzle 41 stops discharging phosphoric acid.

The diluent supply pipe 5 supplies a diluent to the etching solution E in the processing bath 3. Specifically, the diluent supply pipe 5 supplies the diluent to the processing bath 3. The diluent supply pipe 5 is an example of a supply pipe. Specifically, the diluent supply pipe 5 includes a diluent supply nozzle 51 and a diluent supply pipe 52.

The diluent supply nozzle 51 is disposed above the processing bath 3. The diluent supply nozzle 51 is a hollow tubular member. A plurality of discharge holes are formed in the diluent supply nozzle 51. In the present embodiment, the diluent supply nozzle 51 extends in the Y direction. The plurality of discharge holes of the diluent supply nozzle 51 are formed at equal intervals in the Y direction.

The diluent supply pipe 52 passes the diluent to the diluent supply nozzle 51. When the diluent is supplied to the diluent supply nozzle 51 through the diluent supply pipe 52, the diluent is discharged from the plurality of discharge holes of the diluent supply nozzle 51. In the present embodiment, the diluent supply pipe 5 discharges the diluent toward the upper end surface of the side wall of the inner tank 31. In the processing bath 3, the etching liquid E flows from the inner bath 31 to the outer bath 32 via the upper end surface of the side wall of the inner bath 31. Therefore, the diluent discharged to the upper end surface of the side wall of the inner tank 31 is supplied to the outer tank 32 by the flow of the etching liquid E.

According to the present embodiment, since the diluent is discharged to the upper end surface of the side wall of the inner tank 31, evaporation of water from the diluent immediately after the diluent is supplied can be suppressed. Specifically, as described above, the etching solution E is heated to 120 ℃ or higher and 160 ℃ or lower. Therefore, when the diluent is discharged to the surface of the etching liquid E in the inner tank 31 or the outer tank 32, the water is easily evaporated from the diluent immediately after the diluent is supplied. In contrast, in comparison with the case where the diluent is discharged to the surface of the etching liquid E in the inner tank 31 or the outer tank 32, the evaporation of water from the diluent immediately after the diluent is supplied can be suppressed by discharging the diluent to the upper end surface of the side wall of the inner tank 31.

The height of the upper end of the side wall of the outer tank 32 is higher than the height of the upper end of the side wall of the inner tank 31. The etching liquid E in the outer tank 32 is discharged from the outer tank 32 by the etching liquid circulating unit 8. Therefore, the etching solution E does not overflow from the processing bath 3.

Next, the pressure measuring unit 6, the first bubbling unit 7, and the etching liquid circulating unit 8 will be described with reference to fig. 2.

The pressure measuring unit 6 measures the pressure of the etching solution E stored in the processing bath 3 at a predetermined depth. In the present embodiment, the pressure measurement unit 6 includes a gas supply pipe 61 and a pressure sensor 62.

The gas supply pipe 61 circulates gas. For example, the gas is an inert gas. Specifically, the gas can be nitrogen. The tip of the gas supply pipe 61 is immersed in the etching liquid E in the outer tank 32, and the gas supply pipe 61 blows gas out of the etching liquid E in the outer tank 32.

The pressure sensor 62 measures the pressure of the gas discharged from the tip of the gas supply pipe 61. The pressure of the gas discharged from the tip of the gas supply pipe 61 indicates the pressure of the etching liquid E stored in the processing bath 3 at a predetermined depth. In the present embodiment, the pressure of the gas discharged from the tip of the gas supply pipe 61 indicates the pressure of the etching liquid E stored in the outer tank 32 at a predetermined depth. In the following description, the pressure of the gas discharged from the tip of the gas supply pipe 61 or the pressure of the etching liquid E stored in the outer tank 32 at a predetermined depth may be referred to as "gas discharge pressure".

The first bubbling portion 7 supplies bubbles to the plurality of substrates W immersed in the etching liquid E in the inner tank 31. Specifically, the first bubbling portion 7 includes a plurality of gas supply nozzles 71 and gas supply pipes 72. In the present embodiment, the first bubbling portion 7 includes two gas supply nozzles 71, but the first bubbling portion 7 may include one gas supply nozzle 71, or may include three or more gas supply nozzles 71.

The plurality of gas supply nozzles 71 are disposed on the bottom side of the inner tank 31. More specifically, the plurality of gas supply nozzles 71 are disposed in the inner tank 31 below the plurality of substrates W immersed in the etching liquid E in the inner tank 31.

The gas supply nozzles 71 are respectively hollow tubular members. Each of the gas supply nozzles 71 has a plurality of discharge holes 711, which will be described later with reference to fig. 7, and supplies bubbles to the plurality of substrates W immersed in the etching liquid E in the inner tank 31 by blowing gas from the discharge holes 711. For example, the gas is an inert gas. Specifically, the gas can be nitrogen.

The gas supply pipe 72 allows gas to flow to the plurality of gas supply nozzles 71. The gas supply pipe 72 supplies bubbles to the plurality of substrates W immersed in the etching liquid E in the inner tank 31 by flowing gas. As a result, as will be described later with reference to fig. 7, the substrate W can be uniformly etched while suppressing non-uniformity of the silicon concentration in the etching liquid E.

The etching liquid circulating part 8 circulates the etching liquid E between the outer tank 32 and the inner tank 31. Specifically, the etching liquid circulation unit 8 includes a plurality of etching liquid supply nozzles 81, a circulation pipe 82, a circulation pump 83, a circulation heater 84, and a circulation filter 85. In the present embodiment, the etching liquid circulation unit 8 includes two etching liquid supply nozzles 81, but the etching liquid circulation unit 8 may include one etching liquid supply nozzle 81, or may include three or more etching liquid supply nozzles 81.

The etching liquid supply nozzles 81 are disposed on the bottom side of the inner tank 31. The etching liquid supply nozzles 81 are each a hollow tubular member. A plurality of discharge holes are formed in each etching liquid supply nozzle 81. In the present embodiment, the etching liquid supply nozzle 81 extends in the Y direction. The plural discharge holes of the etching liquid supply nozzle 81 are formed at equal intervals in the Y direction.

One end of the circulation pipe 82 is connected to the outer tank 32, and the etching solution E flows from the outer tank 32 into the circulation pipe 82. The circulation pipe 82 flows the etching solution E to the plurality of etching solution supply nozzles 81.

The circulation pump 83 is attached to the circulation pipe 82. The circulation pump 83 drives the etching solution E to flow through the circulation pipe 82 by the pressure of the fluid. As a result, the etching liquid E flows from the outer tank 32 to the inner tank 31 through the circulation pipe 82. Specifically, the etching liquid E flows through the circulation pipe 82, and is discharged from the discharge hole of the etching liquid supply nozzle 81 into the inner tank 31. That is, the etching solution E is supplied from the etching solution supply nozzle 81 into the inner tank 31. Further, by discharging the etching liquid E from the etching liquid supply nozzle 81 into the inner tank 31, the etching liquid E flows from the inner tank 31 to the outer tank 32 via the upper end surface of the side wall of the inner tank 31.

The circulation heater 84 and the circulation filter 85 are attached to the circulation pipe 82. The circulation heater 84 heats the etching solution E flowing through the circulation pipe 82. Specifically, the circulation heater 84 heats the etching solution E to a temperature of 120 ℃ to 160 ℃. The circulation filter 85 removes foreign matters from the etching solution E flowing through the circulation pipe 82.

Next, the structure of the diluent supply pipe 5 will be further described with reference to fig. 3. Fig. 3 is a diagram showing the structure of the substrate processing apparatus 100 according to the present embodiment. As shown in fig. 3, the diluent supply pipe 5 further includes a flow rate control valve 53, a maximum flow rate adjustment valve 54, and an opening/closing valve 55. The flow rate control valve 53, the maximum flow rate adjustment valve 54, and the opening/closing valve 55 are attached to the diluent supply pipe 52.

The flow rate control valve 53 controls the flow rate of the diluent flowing through the diluent supply pipe 52. That is, the flow control valve 53 controls the flow rate of the diluent supplied from the diluent supply nozzle 51 to the etching liquid E. For example, the flow control valve 53 controls the flow rate of the diluent by adjusting the opening degree of an orifice. For example, the flow control valve 53 can be an automatic control valve.

The maximum flow rate adjustment valve 54 adjusts the maximum flow rate of the diluent flowing through the diluent supply pipe 52. The maximum flow rate regulating valve 54 is, for example, a needle valve. In the following description, the maximum flow rate of the diluent flowing through the diluent supply pipe 52 may be referred to as "maximum flow rate of the diluent". In the case where the maximum flow rate of the diluent controlled by the flow control valve 53 is equal to or greater than the maximum flow rate of the diluent adjusted by the maximum flow rate adjustment valve 54, the maximum flow rate of the diluent is a flow rate depending on the opening ratio of the maximum flow rate adjustment valve 54. That is, the maximum flow rate of the diluent is limited by the maximum flow rate of the diluent adjusted by the maximum flow rate adjustment valve 54. On the other hand, in the case where the maximum flow rate of the diluent adjusted by the maximum flow rate adjustment valve 54 is larger than the maximum flow rate of the diluent controlled by the flow rate control valve 53, the maximum flow rate of the diluent is limited by the maximum flow rate of the diluent controlled by the flow rate control valve 53.

The opening and closing valve 55 is, for example, an electromagnetic valve. The on-off valve 55 is controlled by the control device 110 (control unit 111). The opening/closing valve 55 opens and closes the flow path of the diluent supply pipe 52 to control the flow of the diluent flowing through the diluent supply pipe 52. Specifically, when the opening/closing valve 55 is opened, the diluent flows into the diluent supply nozzle 51 through the diluent supply pipe 52. As a result, the diluent is discharged from the diluent supply nozzle 51. On the other hand, when the on-off valve 55 is closed, the flow of the diluent is shut off, and the diluent supply nozzle 51 stops discharging the diluent.

Next, the structure of the substrate processing apparatus 100 according to the present embodiment will be described with reference to fig. 3. As shown in fig. 3, the substrate processing apparatus 100 further includes a controller 140 and a driving unit 160.

The controller 140 controls the opening degree of the flow rate control valve 53 via the drive unit 160 so that a physical quantity corresponding to the concentration of phosphoric acid (a physical quantity corresponding to the concentration of phosphoric acid in the etching solution E) becomes a target value. That is, the controller 140 controls the flow rate of the diluent supplied from the diluent supply nozzle 51 to the etching liquid E so that the physical quantity corresponding to the concentration of the phosphoric acid becomes a target value. The flow rate of the diluent supplied to the etching solution E is an example of a parameter for varying a physical quantity corresponding to the concentration of the phosphoric acid. The controller 140 is an example of a parameter control section.

In the present embodiment, the controller 140 controls the flow rate of the diluent so that the specific gravity value of the phosphoric acid in the etching solution E becomes a target value. In the following description, the specific gravity value of phosphoric acid in the etching solution E may be referred to as "specific gravity value of phosphoric acid".

Specifically, the controller 140 measures the specific gravity value of the phosphoric acid based on the measurement result of the pressure sensor 62. The controller 140 controls the flow rate of the diluent so that the measurement result (the specific gravity value of the phosphoric acid) of the pressure sensor 62 becomes a target value. For example, the controller 140 outputs a PID control value to the driving unit 160 based on the measurement result of the pressure sensor 62. Specifically, the controller 140 outputs a current signal indicating a PID control value to the driving part 160.

The specific gravity of phosphoric acid and the gas ejection pressure (the pressure of the gas ejected from the distal end of the gas supply pipe 61) are correlated with each other. Specifically, the larger the specific gravity value of phosphoric acid, the larger the weight per unit volume of the etching liquid E, and the larger the gas ejection pressure. Therefore, the specific gravity value of the phosphoric acid can be measured based on the measurement result of the pressure sensor 62.

The controller 140 controls the driving unit 160 to drive the flow rate control valve 53. As a result, the opening degree of the flow control valve 53 is controlled so that the specific gravity value of phosphoric acid becomes a target value. For example, the driving portion 160 is an electro-pneumatic regulator.

Here, the control device 110 is further explained. As described with reference to fig. 2, the storage unit 112 of the control device 110 stores data indicating a target value of the physical quantity corresponding to the concentration of phosphoric acid. In the present embodiment, the storage unit 112 stores data indicating a target value of a specific gravity value of phosphoric acid, which is a target value of a physical quantity corresponding to a concentration of phosphoric acid. The control device 110 (control unit 111) sets the target value stored in the storage unit 112 in the controller 140.

In the present embodiment, the control device 110 (storage unit 112) stores a first target value and a second target value lower than the first target value as target values of the physical quantity corresponding to the concentration of phosphoric acid. The controller 110 (controller 111) changes the target value of the physical quantity corresponding to the concentration of phosphoric acid from the first target value to the second target value in the etching process of the substrate W. The control device 110 is an example of the changing unit.

Specifically, the first target value and the second target value are target values with respect to a specific gravity value of phosphoric acid. Hereinafter, the first target value of the specific gravity value of phosphoric acid may be referred to as "first target value TV 1". In addition, the second target value of the specific gravity value of phosphoric acid may be described as "second target value TV 2".

The second target value TV2 represents a lower value than the first target value TV 1. The controller 110 (controller 111) sets the first target value TV1 in the controller 140 before the etching process of the substrate W is started. Thereafter, the control device 110 (control unit 111) sets the second target value TV2 in the controller 140. For example, the controller 110 (controller 111) sets the second target value TV2 in the controller 140 after a predetermined time has elapsed from the start of the etching process of the substrate W.

Here, a substrate W to be processed by the substrate processing apparatus 100 according to the present embodiment will be described with reference to fig. 4. Fig. 4 is a diagram illustrating a substrate W before being processed by the substrate processing apparatus 100 according to the present embodiment. For example, the substrate W processed by the substrate processing apparatus 100 of the present embodiment is used for a three-dimensional flash memory (e.g., a three-dimensional NAND flash memory).

As shown in fig. 4, the substrate W includes a base material S and a laminated structure M. The substrate S extends in the XZ plane and is in the form of a film. For example, the substrate S is made of silicon. The laminated structure M is formed on the upper surface of the base material S. The laminated structure M is formed extending in the Y direction from the upper surface of the base material S. The laminated structure M includes oxide films Ma and nitride films Mb alternately laminated in the Y direction. For example, the oxide film Ma is a silicon oxide film. For example, the nitride film Mb is a silicon nitride film. The oxide films Ma extend parallel to the upper surfaces of the substrates S, respectively. The nitride films Mb extend parallel to the upper surface of the substrate S.

The laminated structure M has one or more recesses R. The recess R extends from the upper surface of the laminated structure M to the base material S, and a part of the upper surface of the base material S is exposed from the recess R. Further, side surfaces of the oxide film Ma and the nitride film Mb are exposed from the interface of the recess R. In the case where the substrate W is used for a semiconductor product, the recess R is used as a groove or a hole, for example.

The second target value TV2 described with reference to fig. 3 indicates a value at which the etching rate of the nitride film Mb is greater and the etching rate of the oxide film Ma is smaller than the first target value TV 1. Specifically, the first target value TV1 indicates a value at which the etching rate of the nitride film Mb is higher than the etching rate of the oxide film Ma. Since the second target value TV2 is a lower value than the first target value TV1, when the specific gravity value of phosphoric acid is changed from the first target value TV1 to the second target value TV2, the etching rate of the nitride film Mb increases and the etching rate of the oxide film Ma decreases.

Next, an etching process of the substrate processing apparatus 100 according to the present embodiment will be described with reference to fig. 4 and 5. Fig. 5 is a diagram showing an example of a substrate W processed by the substrate processing apparatus 100 according to the present embodiment.

When the etching process for the substrate W is started, the etching liquid E enters the concave portion R. As a result, the etching liquid E contacts the oxide film Ma and the nitride film Mb at the interface of the recess R.

When the etching process for the substrate W is started, the controller 140 sets the first target value TV1 to the target value of the specific gravity value of phosphoric acid. Therefore, the flow rate of the diluent is controlled so that the specific gravity value of the phosphoric acid in the etching solution E becomes the first target value TV 1.

As described above, the first target value TV1 indicates a value at which the etching rate of the nitride film Mb is greater than the etching rate of the oxide film Ma. In addition, the first target value TV1 indicates a value at which the etching rate of the nitride film Mb is smaller and the etching rate of the oxide film Ma is larger than the second target value TV 2. Therefore, the nitride film Mb and the oxide film Ma are etched with the etching solution E. Specifically, the nitride film Mb and the oxide film Ma are gradually dissolved from the interface side of the recess R by the etching liquid E. However, since the first target value TV1 indicates that the etching rate of the nitride film Mb is greater than the etching rate of the oxide film Ma, the etching amount of the oxide film Ma is smaller than the etching amount of the nitride film Mb.

In the following description, the etching process when the flow rate of the diluent is controlled so that the specific gravity value of phosphoric acid becomes the first target value TV1 may be referred to as a "first etching process".

Thereafter, the control device 110 changes the target value of the specific gravity value of phosphoric acid from the first target value TV1 to the second target value TV 2. That is, the controller 140 sets the second target value TV2 as the target value of the specific gravity value of phosphoric acid. Therefore, the flow rate of the diluent is controlled so that the specific gravity value of the phosphoric acid in the etching solution E becomes the second target value TV 2.

As described above, the second target value TV2 indicates a value at which the etching rate of the nitride film Mb is greater and the etching rate of the oxide film Ma is smaller than the first target value TV 1. Therefore, the etching solution E mainly etches the nitride film Mb.

In the following description, the etching process when the flow rate of the diluent is controlled so that the specific gravity value of phosphoric acid becomes the second target value TV2 may be referred to as a "second etching process".

The second etching process is performed until the nitride film Mb is almost completely dissolved. In other words, the second etching process is performed until the stacked structure M has almost no nitride film Mb.

By performing the first etching process and the second etching process described above, the laminated structure M can be controlled to an arbitrary shape as shown in fig. 5. Therefore, the substrate W can be processed into a more complicated shape. Specifically, the oxide film Ma is etched by the first etching treatment. Since the oxide film Ma is gradually dissolved from the interface side of the concave portion R by the etching liquid E, the shape of the oxide film Ma is tapered toward the concave portion R as shown in fig. 5.

Next, the structure of the pressure measuring unit 6 will be described with reference to fig. 6. Fig. 6 is a diagram showing the structure of the pressure measuring unit 6. As shown in fig. 6, the pressure measuring unit 6 further includes a regulator 63, an opening/closing valve 64, a three-way valve 65, and a branch pipe 66. The gas supply pipe 61 includes an upstream pipe 61a and a downstream pipe 61 b.

The regulator 63 is mounted on the gas supply pipe 61 upstream of the on-off valve 64. More specifically, the regulator 63 is attached to the upstream pipe 61 a. The regulator 63 regulates the pressure of the gas flowing from the regulator 63 into the gas supply pipe 61 to a constant pressure.

The opening/closing valve 64 is attached to the gas supply pipe 61 upstream of the three-way valve 65. More specifically, the on-off valve 64 is attached to the upstream pipe 61 a. The opening/closing valve 64 is, for example, an electromagnetic valve. The on-off valve 64 is controlled by the control device 110 (control unit 111). The opening/closing valve 64 opens and closes the flow path of the gas supply pipe 61 to control the flow of the gas flowing through the gas supply pipe 61. Specifically, when the opening/closing valve 64 is opened, the gas flows through the gas supply pipe 61. As a result, gas is ejected into the etching liquid E from the tip of the gas supply pipe 61. On the other hand, when the on-off valve 64 is closed, the flow of the gas is shut off, and the gas stops being discharged from the tip of the gas supply pipe 61.

The three-way valve 65 is attached to the gas supply pipe 61. Further, a three-way valve 65 is connected to one end of the branch pipe 66. More specifically, the three-way valve 65 is connected to a downstream end of the upstream pipe 61a, an upstream end of the downstream pipe 61b, and one end of the branch pipe 66. The other end of the branch pipe 66 is connected to the pressure sensor 62.

The three-way valve 65 is controlled by the control device 110 (control unit 111). Specifically, the control device 110 (control unit 111) controls the three-way valve 65 to communicate the downstream end of the upstream pipe 61a with the upstream end of the downstream pipe 61b, and to discharge the gas from the downstream end of the downstream pipe 61b (the tip of the gas supply pipe 61). Thereafter, when the control device 110 (control unit 111) measures the gas discharge pressure (the pressure of the gas discharged from the tip of the gas supply pipe 61), the three-way valve 65 is controlled so that the upstream end of the downstream pipe 61b communicates with one end of the branch pipe 66. As a result, the gas discharge pressure is measured by the pressure sensor 62.

Next, the structure of the first bubbling portion 7 will be further described with reference to fig. 7. Fig. 7 is a diagram showing the structure of the first bubbling portion 7 and the processing tank 3. As shown in fig. 7, the first bubbling portion 7 further includes a filter 73, a heater 74, and an exhaust pipe 75. The filter 73 and the heater 74 are attached to the gas supply pipe 72.

The filter 73 removes foreign matters from the gas flowing through the gas supply pipe 72. The heater 74 heats the gas flowing through the gas supply pipe 72 to adjust the temperature of the gas flowing through the gas supply pipe 72. The heater 74 is controlled by the control device 110 (control unit 111). The specific gravity value of the phosphoric acid (the specific gravity value of the phosphoric acid in the etching solution E) can be controlled by adjusting the temperature of the gas flowing through the gas supply pipe 72. Specifically, the specific gravity value of the phosphoric acid can be controlled by adjusting the temperature of the bubbles supplied from the gas supply nozzle 71 to the etching liquid E in the inner tank 31.

The gas supply pipe 72 is connected to one end of the gas supply nozzle 71, and supplies gas to the gas supply nozzle 71. The exhaust pipe 75 is connected to the other end of the gas supply nozzle 71. The gas that is not ejected from the ejection holes 711 of the gas supply nozzle 71 and flows through the gas supply nozzle 71 flows into the exhaust pipe 75.

Next, the gas supply nozzle 71 will be described. As shown in fig. 7, a plurality of discharge holes 711 are formed in the upper surface portion of the gas supply nozzle 71. In the present embodiment, the gas supply nozzle 71 extends in the Y direction. The plurality of ejection holes 711 are formed at equal intervals in the Y direction.

The bubbles discharged from the discharge holes 711 are supplied to the substrates W. Specifically, the bubbles move upward along the surfaces of the plurality of substrates W. As a result, the etching liquid E in contact with the surface of each substrate W is effectively replaced with fresh etching liquid E by the bubbles. Therefore, the etching liquid E in the concave portion R (fig. 4) formed on the surface of the substrate W can be effectively replaced with fresh etching liquid E by the diffusion phenomenon. Therefore, the oxide film Ma and the nitride film Mb exposed at the interface of the recessed portion R can be efficiently etched with the etching liquid E from the position close to the interface of the recessed portion R to the position away from the interface of the recessed portion R.

As described with reference to fig. 4, the substrate W has a silicon nitride film (nitride film Mb). When the silicon nitride film (silicon nitride film Mb) is etched with a liquid containing phosphoric acid (etching liquid E), silicon is generated as a reactant. The silicon is eluted into the etching solution E. Therefore, the eluted silicon changes the silicon concentration around the surface of the substrate W. When the surface of the substrate W has a three-dimensional uneven shape, the silicon concentration in the periphery of the surface of the substrate W becomes uneven due to the shape. In contrast, according to the present embodiment, the bubbles move upward along the surface of the substrate W. As a result, even when the surface of the substrate W has three-dimensional irregularities, the substrate W can be uniformly etched while suppressing non-uniformity of the silicon concentration in the etching liquid E.

Next, the structure of the processing bath 3 will be further described with reference to fig. 7. As shown in fig. 7, the processing bath 3 further includes a bath heater 33. The tank heater 33 is disposed on the bottom surface of the inner tank 31 and heats the inner tank 31. For example, the tank heater 33 heats the inner tank 31 at a temperature of 120 ℃ to 160 ℃.

Next, the configuration of the control device 110 will be further described with reference to fig. 8. Fig. 8 is a block diagram showing the configuration of the control device 110. As shown in fig. 8, the control device 110 further includes an input unit 113.

The input unit 113 receives data input by the operator. The input unit 113 is a user interface device operated by an operator. The input unit 113 inputs data corresponding to an operation by the operator to the control unit 111. The input unit 113 has, for example, a keyboard and a mouse. The input section 113 may have a touch sensor.

For example, the input unit 113 receives an input of a set value of a parameter that can be set by the operator in the procedure data. The input unit 113 receives an input of a target value of the physical quantity corresponding to the concentration of phosphoric acid. In the present embodiment, the input unit 113 receives inputs of the first target value TV1 and the second target value TV 2. The input unit 113 receives an input of a set value of the specific gravity change period SGV described later with reference to fig. 9.

Next, a change in the specific gravity value of phosphoric acid during the etching treatment will be described with reference to fig. 9. Fig. 9 is a diagram showing an example of a change in the specific gravity value of phosphoric acid when the etching process is performed by the substrate processing apparatus 100 according to the present embodiment.

In fig. 9, the vertical axis represents the specific gravity of phosphoric acid. The horizontal axis represents processing time. In fig. 9, the broken line indicates the specific gravity value of the phosphoric acid measured by the controller 140. The solid line represents the target value of the specific gravity value of phosphoric acid. In the following description, the specific gravity value of phosphoric acid measured by the controller 140 may be referred to as a "measured value".

As shown in fig. 9, when the first target value TV1 is set in the controller 140, the flow rate of the diluent is controlled so that the specific gravity value (measured value) of phosphoric acid becomes the first target value TV 1. In the etching process, when the target value of the specific gravity value of phosphoric acid is changed from the first target value TV1 to the second target value TV2, the flow rate of the diluent is controlled so that the specific gravity value (measured value) of phosphoric acid becomes the second target value TV 2.

The shape of the oxide film Ma described with reference to fig. 5 depends on the length of the period SGV until the specific gravity value (measured value) of phosphoric acid changes from the first target value TV1 to the second target value TV 2. Hereinafter, the period SGV until the specific gravity value (measured value) of phosphoric acid changes from the first target value TV1 to the second target value TV2 may be referred to as "specific gravity change period SGV". For example, the length of the SGV during the change in specific gravity is controlled by the flow rate of the diluent.

In the present embodiment, the set value of the specific gravity change period SGV is stored in the storage unit 112 (fig. 8). Specifically, the input unit 113 (fig. 8) receives an input of a setting value of the specific gravity change period SGV. The control device 110 (control unit 111) adjusts, for example, the flow rate of the diluent so that the length of the SGV during the change in specific gravity coincides with a set value. For example, the operator can input the set value of the specific gravity change period SGV so that the length of the specific gravity change period SGV is relatively long. By making the length of the SGV relatively long during the change in specific gravity, the flow rate of the diluent can be prevented from increasing suddenly. As a result, the uniformity of the nitride film Mb in the surface of the substrate W can be improved as compared with the case where the flow rate of the diluent is suddenly increased.

Next, a substrate processing method according to the present embodiment will be described with reference to fig. 10. Fig. 10 is a flowchart showing a substrate processing method according to the present embodiment. The substrate processing method according to the present embodiment can be implemented by the substrate processing apparatus 100 described with reference to fig. 1 to 9. A substrate processing method performed by the substrate processing apparatus 100 described with reference to fig. 1 to 9 will be described below. As shown in fig. 10, the substrate processing method of the present embodiment includes steps S1 to S5.

First, when the etching process of the substrates W is started, the plurality of substrates W are immersed in the etching solution E (step S1). Specifically, the substrate holding portion 130 moves to the processing position. As a result, the plurality of substrates W held by the substrate holding portion 130 are accommodated in the inner tank 31, and the plurality of substrates W are immersed in the etching liquid E in the inner tank 31.

When the plurality of substrates W are immersed in the etching solution E, the first etching process is performed (step S2). At this time, the parameter for varying the physical quantity corresponding to the concentration of phosphoric acid is controlled so that the physical quantity corresponding to the concentration of phosphoric acid (the concentration of phosphoric acid in the etching solution E) becomes the first target value. In the present embodiment, the flow rate of the diluent supplied to the etching liquid E is controlled. Specifically, the controller 140 controls the flow rate control valve 53 via the drive unit 160 so that the specific gravity value of the phosphoric acid becomes the first target value TV 1.

After the plurality of substrates W are immersed in the etching solution E for a predetermined time, the control device 110 (control unit 111) changes the target value of the physical quantity corresponding to the concentration of the phosphoric acid from the first target value to the second target value (step S3). In the present embodiment, the control device 110 (control unit 111) changes the target value of the specific gravity value of phosphoric acid from the first target value TV1 to the second target value TV 2. More specifically, the control device 110 (control unit 111) changes the target value set in the controller 140 from the first target value TV1 to the second target value TV 2.

When the target value of the physical quantity corresponding to the concentration of phosphoric acid is changed from the first target value to the second target value, the second etching process is performed (step S4). At this time, the parameter for varying the physical quantity corresponding to the concentration of phosphoric acid is controlled so that the physical quantity corresponding to the concentration of phosphoric acid becomes the second target value. In the present embodiment, the flow rate of the diluent supplied to the etching liquid E is controlled. Specifically, the controller 140 controls the flow rate control valve 53 via the drive unit 160 so that the specific gravity value of the phosphoric acid becomes the second target value TV 2.

After the target value of the physical quantity corresponding to the concentration of phosphoric acid is changed from the first target value to the second target value and a predetermined time has elapsed, the plurality of substrates W are pulled up from the etching solution E (step S5), and the process shown in fig. 10 is ended. Specifically, the substrate holding portion 130 moves from the processing position to the retracted position. As a result, the plurality of substrates W held by the substrate holding portion 130 are pulled up from the etching liquid E in the inner tank 31.

Embodiment 1 of the present invention is described above with reference to fig. 1 to 10. According to this embodiment, the laminated structure M can be processed into a more complicated shape than a structure in which a plurality of flat oxide films Ma are arranged in a comb shape. Specifically, the shape of the oxide film Ma can be a taper shape.

In addition, according to this embodiment, the oxide film Ma can be etched. Therefore, an increase in the thickness of the oxide film Ma can be suppressed as compared with the case where the nitride film Mb is mainly etched.

Specifically, silicon dissolved in the etching solution E during the etching treatment may be deposited on the surface of the oxide film Ma. The thickness of the oxide film Ma increases by precipitating silicon on the surface of the oxide film Ma. In contrast, according to this embodiment, since the oxide film Ma can be etched by the first etching treatment, an increase in the thickness of the oxide film Ma can be suppressed as compared with the case where the nitride film Mb is mainly etched.

In addition, according to the present embodiment, the shape of the oxide film Ma can be controlled by controlling the length of the specific gravity change period SGV to a set value. Specifically, when the set value of the SGV is relatively small during the change of the specific gravity value, as shown in fig. 11A, the width MW of the tip of the oxide film Ma increases, and the gradient M θ of the oxide film Ma in the direction (Z direction) from the interface of the recess R (fig. 5) to the depth decreases. On the other hand, when the set value of the SGV is relatively large during the change of specific gravity, as shown in fig. 11B, the width MW of the tip of the oxide film Ma decreases, and the gradient M θ of the oxide film Ma in the direction (Z direction) from the interface of the recess R (fig. 5) to the depth increases.

In the present embodiment, the length of the specific gravity change period SGV is controlled to be a set value, but the length of the specific gravity change period SGV may not be controlled.

[ embodiment 2]

Next, embodiment 2 of the present invention will be described with reference to fig. 1 to 8 and fig. 10 to 12. However, the description of the different matters from embodiment 1 is omitted, and the description of the same matters as embodiment 1 is omitted. In embodiment 2, unlike embodiment 1, the length of the SGV during the period of change in the specific gravity value is not controlled by a set value.

Fig. 12 is a diagram showing an example of a change in the specific gravity value of phosphoric acid when the etching process is performed by the substrate processing apparatus 100 according to the present embodiment. In fig. 12, the vertical axis represents the specific gravity value of phosphoric acid. The horizontal axis represents processing time. In fig. 12, the broken line indicates the measured value (the specific gravity value of phosphoric acid measured by the controller 14). The solid line represents the target value of the specific gravity value of phosphoric acid.

As shown in fig. 12, in the present embodiment, the target value changes stepwise from the first target value TV1 to the second target value TV 2. Specifically, in the present embodiment, the input unit 113 (fig. 8) of the control device 110 receives inputs of a plurality of intermediate target values TX (fig. 12) in addition to the first target value TV1 and the second target value TV 2. The plurality of intermediate target values TX represents values between the first target value TV1 and the second target value TV 2. In addition, the plurality of intermediate target values TX indicate mutually different values.

In the present embodiment, as shown in fig. 12, the plurality of intermediate target values TX includes first to third intermediate target values TX1 to TX 3. The first intermediate target value TX1 to the third intermediate target value TX3 decrease in this order.

In the second etching process (step S4 in fig. 10), the control device 110 (control unit 111) changes the target values set in the controller 140 in the order of the first intermediate target value TX1, the second intermediate target value TX2, the third intermediate target value TX3, and the second target value TV2 (fig. 12). That is, in the second etching process, the control device 110 (control unit 111) changes the target value of the specific gravity value of phosphoric acid stepwise from the first target value TV1 to the second target value TV 2.

According to the present embodiment, the length of the gravity change period SGV varies according to the number of intermediate target values TX. Specifically, the length of the SGV during the change of the specific gravity value becomes longer as the number of the intermediate target values TX increases.

In addition, according to the present embodiment, since the length of the gravity value change period SGV is controlled in accordance with the number of intermediate target values TX, the shape of the laminated structure M can be controlled in accordance with the number of intermediate target values TX, as in embodiment 1.

Embodiment 2 of the present invention is described above with reference to fig. 1 to 8 and 10 to 12. According to the present embodiment, the length of the SGV during the period of change in the specific gravity value can be controlled to control the shape of the laminated structure M.

In the present embodiment, the number of the intermediate target values TX can be arbitrarily changed, but the length of time (the length of the holding time) for which the specific gravity value (the measured value) of the phosphoric acid is held at each intermediate target value TX may be arbitrarily set. In this case, the number of the intermediate target values TX may be a constant number or may be arbitrarily changed.

In the present embodiment, the target value is changed stepwise, but the target value may be changed smoothly.

[ embodiment 3]

Next, embodiment 3 of the present invention will be described with reference to fig. 1, 2, and 4 to 13. However, the description is different from the embodiments 1 and 2, and the description of the same matters as the embodiments 1 and 2 is omitted. Embodiment 3 differs from embodiments 1 and 2 in the configuration of the diluent supply pipe 5. In embodiment 3, the length of the specific gravity change period SGV is controlled by a set value, as in embodiment 1.

Fig. 13 is a diagram showing the structure of the substrate processing apparatus 100 according to the present embodiment. As shown in fig. 13, the diluent supply pipe 5 includes a diluent supply nozzle 51, a first diluent supply pipe 52a, a second diluent supply pipe 52b, a flow rate control valve 53, a first maximum flow rate adjustment valve 54a, a second maximum flow rate adjustment valve 54b, a first opening/closing valve 55a, and a second opening/closing valve 55 b.

The flow rate control valve 53, the first maximum flow rate adjustment valve 54a, and the first opening/closing valve 55a are attached to the first diluent supply pipe 52 a. Specifically, the flow control valve 53, the first maximum flow rate adjustment valve 54a, and the first opening/closing valve 55a are arranged in this order from the upstream side to the downstream side of the first diluent supply pipe 52 a. The diluent supply nozzle 51 is connected to one end of the first diluent supply pipe 52 a.

The second diluent supply pipe 52b is provided with a second maximum flow rate adjustment valve 54b and a second opening/closing valve 55 b. One end of the second diluent supply pipe 52b is connected to the first diluent supply pipe 52a between the flow control valve 53 and the first maximum flow rate adjustment valve 54 a. The other end of the second diluent supply pipe 52b is connected to the first diluent supply pipe 52a between the first opening/closing valve 55a and the diluent supply nozzle 51.

The flow rate control valve 53 controls the flow rate of the diluent flowing through the first diluent supply pipe 52a and the second diluent supply pipe 52 b. That is, the flow control valve 53 controls the flow rate of the diluent supplied from the diluent supply nozzle 51 to the etching liquid E. For example, the flow control valve 53 adjusts the opening degree of an orifice to control the flow rate of the diluent. For example, the flow control valve 53 can be an automatic control valve.

The first maximum flow rate adjustment valve 54a adjusts the maximum flow rate of the diluent flowing through the first diluent supply pipe 52 a. Similarly, the second maximum flow rate adjustment valve 54b adjusts the maximum flow rate of the diluent flowing through the second diluent supply pipe 52 b. For example, the first maximum flow rate adjustment valve 54a and the second maximum flow rate adjustment valve 54b are needle valves. In the following description, the maximum flow rate of the diluent flowing through the first diluent supply pipe 52a may be referred to as "first maximum flow rate". Similarly, the maximum flow rate of the diluent flowing through the second diluent supply pipe 52b may be referred to as "second maximum flow rate".

In the present embodiment, the first maximum flow rate is a flow rate that depends on the opening ratio of the first maximum flow rate adjustment valve 54 a. In addition, the second maximum flow rate is a flow rate depending on the opening ratio of the second maximum flow rate adjustment valve 54 b. The second maximum flow rate represents a value greater than the first maximum flow rate.

For example, the first opening-closing valve 55a and the second opening-closing valve 55b are electromagnetic valves. The first opening/closing valve 55a and the second opening/closing valve 55b are controlled by the control device 110 (control unit 111). Specifically, when the diluent is discharged from the diluent supply nozzle 51, the control device 110 (control unit 111) opens one of the first on-off valve 55a and the second on-off valve 55b and closes the other.

The first opening/closing valve 55a opens and closes the flow path of the first diluent supply pipe 52a to control the flow of the diluent flowing through the first diluent supply pipe 52 a. Specifically, when the first opening/closing valve 55a is opened, the diluent flows into the diluent supply nozzle 51 through the first diluent supply pipe 52 a. As a result, the diluent is discharged from the diluent supply nozzle 51. On the other hand, when the first opening/closing valve 55a is closed, the flow of the diluent flowing through the first diluent supply pipe 52a is shut off.

The second opening/closing valve 55b opens and closes the flow path of the second diluent supply pipe 52b to control the flow of the diluent flowing through the second diluent supply pipe 52 b. Specifically, when the second opening/closing valve 55b is opened, the diluent flows into the diluent supply nozzle 51 through the second diluent supply pipe 52 b. As a result, the diluent is discharged from the diluent supply nozzle 51. On the other hand, when the second opening/closing valve 55b is closed, the flow of the diluent flowing through the second diluent supply pipe 52b is shut off.

In the present embodiment, the controller 110 (the controller 111) selects the maximum flow rate of the diluent from the first maximum flow rate and the second maximum flow rate before the second etching process (step S4 in fig. 10) is started or during the second etching process, and controls the length of the specific gravity change period SGV (fig. 9). Specifically, the operator operates the input unit 113 (fig. 8) of the control device 110 to input an instruction (set value) for selecting one of the first maximum flow rate and the second maximum flow rate. The controller 110 (the control unit 111) selects the maximum flow rate of the diluent from the first maximum flow rate and the second maximum flow rate based on an instruction (set value) from the operator before the start of the second etching process (step S4 in fig. 10) or during the second etching process.

Specifically, the length of the SGV during the change in specific gravity is shorter as the maximum flow rate of the diluent is larger. Thus, in the case where the length of the SGV during the change in the specific gravity value is relatively short, the operator selects the second maximum flow rate. As a result, the controller 110 (controller 111) closes the first on-off valve 55a and opens and closes the second on-off valve 55b to control the supply of the diluent to the etching liquid E. On the other hand, in the case where the length of the SGV during the change of specific gravity is relatively long, the operator selects the first maximum flow rate. As a result, the controller 110 (controller 111) closes the second on-off valve 55b and opens and closes the first on-off valve 55a to control the supply of the diluent to the etching liquid E.

When the controller 110 (controller 111) keeps the specific gravity value of the phosphoric acid at the first target value TV1 or the second target value TV2, the second on-off valve 55b is closed and the first on-off valve 55a is opened and closed to control the supply of the diluent to the etching liquid E.

Embodiment 3 of the present invention is described above with reference to fig. 1, 2, and 4 to 13. According to the present embodiment, the length of the SGV during the change in specific gravity can be controlled by selecting the maximum flow rate of the diluent. Therefore, the shape of the laminated structure M can be controlled as in embodiment 1.

In the present embodiment, the substrate processing apparatus 100 includes two supply pipes of the diluent (the supply pipe of the first maximum flow rate and the supply pipe of the second maximum flow rate), but the substrate processing apparatus 100 may include three or more supply pipes of the diluent having different maximum flow rates.

In the present embodiment, the operator operates the input unit 113 (fig. 8) of the control device 110 to input an instruction (set value) to select one of the first maximum flow rate and the second maximum flow rate, but the control device 110 may be configured to input an instruction to select one of the set value of the specific gravity value change period SGV corresponding to the first maximum flow rate and the set value of the specific gravity value change period SGV corresponding to the second maximum flow rate.

[ embodiment 4]

Next, embodiment 4 of the present invention will be described with reference to fig. 1, 2, 4 to 12, and 14. However, the description is different from the embodiments 1 to 3, and the description of the same matters as the embodiments 1 to 3 is omitted. Embodiment 4 is different from embodiments 1 to 3 in the structure of the diluent supply pipe 5. In embodiment 4, the length of the specific gravity change period SGV is controlled by a set value, as in embodiment 1.

Fig. 14 is a diagram showing the structure of the substrate processing apparatus 100 according to the present embodiment. As shown in fig. 14, the diluent supply pipe 5 includes a diluent supply nozzle 51, a diluent supply pipe 52, a flow rate control valve 53, a maximum flow rate control valve 54c, and an opening/closing valve 55.

The maximum flow rate control valve 54c is attached to the diluent supply pipe 52. The maximum flow rate control valve 54c controls the maximum flow rate of the diluent flowing through the diluent supply pipe 52. For example, the maximum flow rate control valve 54c is an electric needle valve. The maximum flow rate control valve 54c is controlled by the control device 110 (control unit 111).

The controller 110 (controller 111) controls the maximum flow rate of the diluent by adjusting the opening ratio of the maximum flow rate control valve 54c based on the set value of the SGV during the change of the specific gravity value. In the present embodiment, the maximum flow rate of the diluent is a flow rate that depends on the opening ratio of the maximum flow rate control valve 54 c.

The controller 110 (controller 111) controls the length of the specific gravity value change period SGV by adjusting the opening ratio of the maximum flow rate control valve 54c based on the set value of the specific gravity value change period SGV before the second etching process (step S4 in fig. 10) is started or during the second etching process (fig. 9).

Specifically, the length of the SGV during the change in specific gravity is shorter as the maximum flow rate of the diluent is larger. Therefore, when the set value of the SGV is relatively small during the period when the specific gravity value changes, the control device 110 (control unit 111) relatively increases the opening ratio of the maximum flow rate control valve 54 c. On the other hand, when the set value of the SGV is relatively large during the change of specific gravity, the control device 110 (control unit 111) relatively reduces the opening ratio of the maximum flow rate control valve 54 c.

Embodiment 4 of the present invention is described above with reference to fig. 1, 2, 4 to 12, and 14. According to the present embodiment, the length of the SGV during the change in specific gravity can be controlled by adjusting the maximum flow rate of the diluent. Therefore, the shape of the laminated structure M can be controlled as in embodiment 1.

In the present embodiment, the maximum flow rate control valve 54c is provided in the diluent supply pipe 5, but a mass flow controller may be provided instead of the maximum flow rate control valve 54 c.

[ embodiment 5]

Next, embodiment 5 of the present invention will be described with reference to fig. 1, 2, 4 to 12, and 15. However, the description is different from the embodiments 1 to 4, and the description of the same matters as the embodiments 1 to 4 is omitted. The substrate processing apparatus 100 according to embodiment 5 is different from those according to embodiments 1 to 4. In embodiment 5, the length of the specific gravity change period SGV is controlled by a set value, as in embodiment 1.

Fig. 15 is a diagram showing the structure of the substrate processing apparatus 100 according to the present embodiment. As shown in fig. 15, the control device 110 (control unit 111) controls the maximum flow rate of the diluent by adjusting the maximum output of the drive unit 160 based on the set value of the SGV during the change of the specific gravity value. Specifically, the smaller the maximum output of the driving unit 160 is, the smaller the maximum flow rate of the diluent is.

In the present embodiment, the control device 110 (control unit 111) controls the length of the specific gravity value change period SGV by adjusting the maximum output of the drive unit 160 based on the set value of the specific gravity value change period SGV before the second etching process (step S4 in fig. 10) is started or during the second etching process (fig. 9).

Specifically, the smaller the maximum output of the driving unit 160 is, the longer the specific gravity change period SGV is. Therefore, when the set value of the SGV is relatively small during the period of change in the specific gravity value, the control device 110 (control unit 111) makes the maximum output of the drive unit 160 relatively large. On the other hand, when the set value of SGV is relatively large during the specific gravity change period, control device 110 (control unit 111) relatively reduces the maximum output of drive unit 160.

Embodiment 5 of the present invention is described above with reference to fig. 1, 2, 4 to 12, and 15. According to the present embodiment, the length of the specific gravity change period SGV can be controlled by adjusting the maximum output of the driving unit 160. Therefore, the shape of the laminated structure M can be controlled as in embodiment 1.

In the present embodiment, the control device 110 (control unit 111) adjusts the maximum output of the drive unit 160, but the control device 110 (control unit 111) may adjust the current value (PID control value) of the current signal output from the controller 140 to the drive unit 160 to control the length of the specific gravity value change period SGV.

[ embodiment 6]

Next, embodiment 6 of the present invention will be described with reference to fig. 1, 3 to 12, and 16. However, the description is different from the embodiments 1 to 5, and the description of the same matters as the embodiments 1 to 5 is omitted. Embodiment 6 is different from embodiments 1 to 5 in that the length of the SGV during the change in specific gravity is controlled by adjusting the opening degree of the automatic lid 21. In embodiment 6, the length of the specific gravity change period SGV is controlled by a set value, as in embodiment 1.

Fig. 16 is a sectional view showing the structure of the substrate processing apparatus 100 according to the present embodiment. In the present embodiment, when the specific gravity value (measured value) of phosphoric acid changes from the first target value TV1 to the second target value TV2, the control device 110 (control unit 111) adjusts the opening degree of the automatic lid 21 to control the amount of moisture evaporated from the etching solution E. Specifically, the controller 110 (controller 111) controls the amount of moisture evaporated from the etching solution E per unit time by adjusting the opening degree of the automatic lid 21. Hereinafter, the amount of moisture evaporated from the etching solution E per unit time may be referred to as "the amount of moisture evaporated".

Specifically, as shown in fig. 16, the controller 110 (controller 111) opens the robot lid 21 in the second etching process. When the automatic cover 21 is in the open state, a gap G is formed between the first cover sheet 22 and the second cover sheet 23. The larger the width GW of the gap G, the larger the evaporation amount of the moisture. Further, as the evaporation amount of the moisture increases, the specific gravity value change period SGV becomes longer. Therefore, the larger the width GW of the gap G, the longer the specific gravity change period SGV.

In the present embodiment, the control device 110 (control unit 111) controls the length of the specific gravity value change period SGV by adjusting the size of the width GW of the gap G (the opening degree of the automatic lid 21) based on the set value of the specific gravity value change period SGV before the second etching process (step S4 in fig. 10) is started or during the second etching process (fig. 9).

Specifically, when the set value of the SGV is relatively small during the period of change of the specific gravity value, the control device 110 (control unit 111) suppresses the evaporation amount of the moisture by relatively narrowing the width GW of the gap G (relatively reducing the opening degree of the automatic lid 21). As a result, the length of the gravity change period SGV becomes relatively short. On the other hand, when the set value of the SGV is relatively large during the change of specific gravity, the control device 110 (control unit 111) relatively widens the width GW of the gap G (relatively increases the opening degree of the automatic lid 21) to promote evaporation of water from the etching solution E. As a result, the length of the gravity change period SGV becomes relatively long.

Embodiment 6 of the present invention is described above with reference to fig. 1, 3 to 12, and 16. According to the present embodiment, the length of the SGV during the change in specific gravity can be controlled by adjusting the amount of evaporation of water. Therefore, the shape of the laminated structure M can be controlled as in embodiment 1.

[ embodiment 7]

Next, embodiment 7 of the present invention will be described with reference to fig. 1, 3 to 12, 17, and 18. However, the description is different from the embodiments 1 to 6, and the description of the same matters as the embodiments 1 to 6 is omitted. The substrate processing apparatus 100 according to embodiment 7 is different from those according to embodiments 1 to 6. In embodiment 7, the length of the specific gravity change period SGV is controlled by a set value, as in embodiment 1.

Fig. 17 is a sectional view showing the structure of the substrate processing apparatus 100 according to the present embodiment. In the present embodiment, the substrate processing apparatus 100 further includes the second bubbling unit 9. The second bubbling portion 9 supplies bubbles to the etching solution E in the outer tank 32. The bubbles supplied to the etching liquid E in the outer tank 32 are supplied to the inner tank 31 together with the etching liquid E through the etching liquid circulating section 8. As a result, evaporation of water from the etching liquid E in the inner tank 31 is promoted. Therefore, by supplying bubbles to the etching liquid E in the outer tank 32, the length of the SGV (fig. 9) during the change in specific gravity is relatively long.

The structure of the second bubbling portion 9 will be described below. As shown in fig. 17, the second bubbling portion 9 includes a plurality of gas supply nozzles 91 and gas supply pipes 92. In the present embodiment, the second bubbling portion 9 includes two gas supply nozzles 91, but the second bubbling portion 9 may include one gas supply nozzle 91, or may include three or more gas supply nozzles 91.

The plurality of gas supply nozzles 91 are disposed on the bottom side of the outer tank 32. The gas supply nozzles 91 are respectively hollow tubular members. Each of the gas supply nozzles 91 has a plurality of discharge holes 911, which will be described later with reference to fig. 18, and bubbles are supplied to the etching liquid E in the outer tank 32 by blowing gas from the discharge holes 911. For example, the gas is an inert gas. Specifically, the gas can be nitrogen.

The gas supply pipe 92 supplies gas to the plurality of gas supply nozzles 91. The gas supply pipe 92 supplies bubbles to the etching solution E in the outer tank 32 by flowing gas.

Next, the structure of the second bubbling portion 9 will be further described with reference to fig. 18. Fig. 18 is a diagram showing the structure of the second bubbling portion 9. As shown in fig. 18, the second bubbling portion 9 further includes a filter 93, a heater 94, an exhaust pipe 95, and an opening/closing valve 96. The filter 93, the heater 94, and the opening/closing valve 96 are attached to the gas supply pipe 92.

The filter 93 removes foreign matters from the gas flowing through the gas supply pipe 92. The heater 94 heats the gas flowing through the gas supply pipe 92 to adjust the temperature of the gas flowing through the gas supply pipe 92. The heater 94 is controlled by the control device 110 (control unit 111). The specific gravity value of phosphoric acid can be controlled by adjusting the temperature of the gas flowing through the gas supply pipe 92. Specifically, the specific gravity value of the phosphoric acid can be controlled by adjusting the temperature of the bubbles supplied to the etching liquid E in the inner tank 31 through the etching liquid circulating portion 8.

The gas supply pipe 92 is connected to one end of the gas supply nozzle 91, and supplies gas to the gas supply nozzle 91. The exhaust pipe 95 is connected to the other end of the gas supply nozzle 91. The gas that is not ejected from the ejection holes 911 of the gas supply nozzle 91 and flows through the gas supply nozzle 91 flows into the exhaust pipe 95.

The opening and closing valve 96 is, for example, an electromagnetic valve. The opening/closing valve 96 is controlled by a control device 110 (control unit 111). The opening/closing valve 96 opens and closes a flow path of the gas supply pipe 92 to control the flow of the gas flowing through the gas supply pipe 92. Specifically, when the opening/closing valve 96 is opened, the gas flows into the gas supply nozzle 91 through the gas supply pipe 92. As a result, the gas is ejected from the gas supply nozzle 91. On the other hand, when the opening/closing valve 96 is closed, the gas flow is cut off, and the gas supply nozzle 91 stops spraying the gas.

Next, the gas supply nozzle 91 will be described. As shown in fig. 18, a plurality of discharge holes 911 are formed in the upper surface portion of the gas supply nozzle 91. In the present embodiment, the gas supply nozzle 91 extends in the Y direction. The plurality of discharge holes 911 are formed at equal intervals in the Y direction.

Next, the control device 110 will be described. In the present embodiment, in the second etching process, the controller 110 (controller 111) opens the on-off valve 96. Alternatively, in the second etching process, the controller 110 (controller 111) closes the on-off valve 96. As a result, the length of the gravity change period SGV is controlled (fig. 9).

Specifically, the input unit 113 (fig. 8) of the control device 110 receives one of the first set value and the second set value as the set value of the SGV during the specific gravity value change period. The first set value represents a value smaller than the second set value. When the set value of the SGV is the first set value during the period of change in the specific gravity value, the controller 110 (controller 111) closes the on-off valve 96 to suppress the amount of moisture evaporated from the etching liquid E in the inner tank 31. As a result, the length of the gravity change period SGV becomes relatively short. On the other hand, when the set value of the SGV is the second set value during the specific gravity change period, the controller 110 (controller 111) opens the on-off valve 96 to promote evaporation of water from the etching liquid E in the inner tank 31. As a result, the length of the gravity change period SGV becomes relatively long.

Embodiment 7 of the present invention is described above with reference to fig. 1, 3 to 12, 17, and 18. According to the present embodiment, the length of the SGV during the change in specific gravity can be controlled by adjusting the amount of water evaporated from the etching liquid E in the inner tank 31. Therefore, the shape of the laminated structure M can be controlled as in embodiment 1.

The length of the SGV during the change in specific gravity can be controlled by adjusting the amount of bubbles supplied to the etching liquid E in the outer tank 32. For example, a mass flow controller may be provided in the gas supply pipe 92. In this case, as in embodiment 1, the input unit 113 (fig. 8) of the control device 110 receives an input of an arbitrary value as the set value of the specific gravity value change period SGV.

[ embodiment 8]

Next, embodiment 8 of the present invention will be described with reference to fig. 1 to 9 and fig. 11 to 20. However, the description is different from the embodiments 1 to 7, and the description of the same matters as the embodiments 1 to 7 is omitted. Embodiment 8 is different from embodiments 1 to 7 in that the first target value TV1, the second target value TV2, and the set value of the SGV during the change of the specific gravity value are determined based on the size of the device manufactured using the substrate W.

Fig. 19 is a diagram showing the determination table TL 10. In the present embodiment, the storage unit 112 (fig. 8) stores the determination table TL 10. As shown in fig. 19, the decision table TL10 includes a device size column TL11, a first target value column TL12, a second target value column TL13, and a specific gravity value change period column TL 14. Various device sizes (sizes of devices) are registered on the device size column TL 11. The first target value TL12 has a first target value TV1 registered therein. The second target value TL13 has a second target value TV2 registered therein. The specific gravity change period TL14 has the set value of the specific gravity change period SGV registered therein. The decision table TL10 correlates the size of the device, the first target value TV1, the second target value TV2, and the set value of the SGV during the change of the specific gravity value.

In the present embodiment, the input unit 113 (fig. 8) receives an input of the size of a device manufactured using the substrate W. When data indicating the size of the device is input from the input unit 113, the control unit 111 (fig. 8) refers to the determination table TL10 stored in the storage unit 112 (fig. 8) to determine the first target value TV1, the second target value TV2, and the set value of the SGV during the change of the specific gravity value.

Next, a substrate processing method according to the present embodiment will be described with reference to fig. 20. Fig. 20 is a flowchart showing a substrate processing method according to the present embodiment. For example, the substrate processing method according to the present embodiment can be implemented by the substrate processing apparatus 100 described with reference to fig. 1 to 9. As shown in fig. 20, the substrate processing method of the present embodiment includes steps S11 to S16.

In the present embodiment, the input unit 113 receives an input of the size of a device manufactured using the substrate W before the etching process of the substrate W is started. When the input unit 113 receives an input of the device size, the control unit 111 refers to the determination table TL10 stored in the storage unit 112, and determines the first target value TV1, the second target value TV2, and the set value of the SGV during the change of the specific gravity value (step S11).

Thereafter, the respective processes of step S12 to step S16 are executed. The processing of steps S12 to S16 is the same as the processing of steps S11 to S15 described with reference to fig. 10, and therefore the description thereof is omitted.

Embodiment 8 of the present invention is described above with reference to fig. 1 to 9 and fig. 11 to 20. According to the present embodiment, the shape of the laminated structure M can be controlled to a shape corresponding to the size of the device.

In the present embodiment, the first target value TV1, the second target value TV2, and the set value of the SGV during the change in specific gravity value are determined based on the size of the device, but the first target value TV1 and the second target value TV2 among the set values of the first target value TV1, the second target value TV2, and the SGV during the change in specific gravity value may be determined based on the size of the device. In this case, the specific gravity change period column TL14 may be omitted.

In the present embodiment, the first target value TV1, the second target value TV2, and the set value of the SGV during the change in specific gravity value are determined based on the size of the device, but the first target value TV1, the second target value TV2, and the set value of the SGV during the change in specific gravity value may be determined based on the finished shape of the laminated structure M. Alternatively, the first target value TV1, the second target value TV2, and the set value of the SGV during the change of the specific gravity value may be determined based on the type of the laminated structure M.

Fig. 21 is a diagram showing another example 1 of the determination table (determination table TL 20). In the case where the first target value TV1, the second target value TV2, and the set value of the SGV during the change of the specific gravity value are decided based on the finished shape of the laminated structure M, the storage part 112 (fig. 8) may store the decision table TL 20. As shown in fig. 21, the decision table TL20 includes a finished shape column TL21, a first target value column TL22, a second target value column TL23, and a specific gravity value change period column TL24 of the laminated structure M. Various finished shapes are registered in the finished shape column TL21 of the laminated structure M. For example, the finished shape may represent the slope M θ of the oxide film Ma described with reference to fig. 11A and 11B.

Fig. 22 is a diagram showing another example 2 of the determination table (determination table TL 30). In the case where the first target value TV1, the second target value TV2, and the set value of the SGV during the change of specific gravity value are determined based on the type of the laminated structure M, the storage unit 112 (fig. 8) may store a determination table TL 30. As shown in fig. 22, the decision table TL30 includes a film species column TL31, a first target value column TL32, a second target value column TL33, and a specific gravity value change period column TL 34. The type of the laminated structure M is registered in the film type column TL 31. For example, the type of the stacked structure M may indicate the number of stacked layers of the oxide film Ma and the nitride film Mb described with reference to fig. 4.

The embodiments of the present invention have been described above with reference to the drawings (fig. 1 to 22). However, the present invention is not limited to the above-described embodiments, and can be implemented in various embodiments without departing from the scope of the present invention. In addition, a plurality of constituent elements disclosed in the above embodiments can be changed as appropriate. For example, any one of all the components described in one embodiment may be added to the components of another embodiment, or some of all the components described in one embodiment may be deleted from the embodiments.

For the sake of easy understanding of the present invention, the drawings mainly schematically show the respective components, and the thickness, length, number, interval, and the like of the illustrated components may be different from those of the actual components for the sake of convenience of drawing. The configuration of each component shown in the above embodiments is an example, and is not particularly limited, and various modifications can be made within a range that does not substantially depart from the effects of the present invention.

For example, in the embodiment described with reference to fig. 1 to 22, the controller 140 measures the specific gravity value of the phosphoric acid, but the operator may sample the etching solution E to measure the specific gravity value or concentration of the phosphoric acid.

In the embodiment described with reference to fig. 1 to 22, the diluent is supplied from the outside of the processing bath 3 to the etching solution E in the processing bath 3, but the diluent may be supplied to the etching solution E inside the processing bath 3. For example, the diluent supply nozzle 51 is disposed inside the inner tank 31 or the outer tank 32, so that the diluent can be supplied to the etching liquid E inside the processing tank 3. In the case where the diluent is supplied to the etching solution E inside the processing bath 3, the length of the period SGV during which the specific gravity value changes can be shortened as compared with the case where the diluent is supplied to the etching solution E inside the processing bath 3 from outside the processing bath 3.

In the embodiment described with reference to fig. 1 to 22, the parameter for varying the physical quantity corresponding to the concentration of phosphoric acid is the flow rate of the diluent, but the parameter for varying the physical quantity corresponding to the concentration of phosphoric acid is not limited to the flow rate of the diluent. For example, the parameter for varying the physical quantity corresponding to the concentration of phosphoric acid may be the temperature of the bubbles discharged from the gas supply nozzle 71 (fig. 7). In this case, the controller 110 (the controller 111) controls the heater 74 described with reference to fig. 7 to vary the physical quantity corresponding to the concentration of phosphoric acid. Alternatively, the parameter for varying the physical quantity corresponding to the concentration of phosphoric acid may be the temperature of the bubbles discharged from the gas supply nozzle 91 (fig. 18). Specifically, the parameter for varying the physical quantity corresponding to the concentration of phosphoric acid may be the temperature of the bubbles supplied to the etching liquid E in the inner tank 31 through the etching liquid circulating unit 8. In this case, the control device 110 (control unit 111) controls the heater 94 described with reference to fig. 18 to vary the physical quantity corresponding to the concentration of phosphoric acid.

In the embodiment described with reference to fig. 1 to 22, the tip of the gas supply pipe 61 is immersed in the etching liquid E in the outer tank 32, but the tip of the gas supply pipe 61 may be immersed in the etching liquid E in the control tank provided in the outer tank 32. Specifically, the processing tank 3 includes a control tank provided in the outer tank 32 in addition to the inner tank 31 and the outer tank 32, and the tip of the gas supply pipe 61 can be immersed in the etching liquid E in the control tank. With this configuration, the ejection pressure of the gas can be measured with higher accuracy. Therefore, the specific gravity value of phosphoric acid can be measured with higher accuracy.

Specifically, the height of the surface of the etching liquid E in the outer tank 32 varies due to bubbles generated in the surface of the etching liquid E in the outer tank 32, a decrease in the etching liquid E in the outer tank 32, or the like. The bubbles may be generated when the etching liquid E flows from the inner tank 31 into the outer tank 32. When the circulation pump 83 is driven to flow the etching liquid E into the circulation pipe 82, the etching liquid E in the outer tank 32 may decrease. On the other hand, the control of the height of the liquid level of the etching liquid E in the tank is stable because bubbles generated in the liquid level of the etching liquid E in the outer tank 32, a decrease in the etching liquid E in the outer tank 32, and the like are less likely to affect the control. Therefore, by immersing the tip of the gas supply pipe 61 in the etching liquid E in the control tank, the specific gravity value of phosphoric acid can be measured with higher accuracy.

Industrial applicability

The invention is applicable in the field of processing substrates.

Claims

1. A substrate processing method for etching a substrate having an oxide film and a nitride film alternately stacked in a processing bath with an etching solution containing phosphoric acid,

comprises the following steps:

a first treatment step of controlling a parameter for varying a physical quantity corresponding to a concentration of the phosphoric acid in the etching solution so that the physical quantity becomes a first target value; and

a second processing step of controlling the parameter so that the physical quantity becomes a second target value lower than the first target value,

the second target value represents a target value of the physical quantity in which the etching rate of the nitride film is greater and the etching rate of the oxide film is smaller than the first target value.

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

and controlling a length of a specific gravity change period, the length of the specific gravity change period indicating a length of a period until the physical quantity is changed from the first target value to the second target value in the second processing step.

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

in the second processing step, the target value is changed stepwise from the first target value to the second target value to control the length of the specific gravity value change period.

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

and adjusting the flow rate of the diluent supplied to the etching solution to control the length of the specific gravity value change period.

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

adjusting the amount of water evaporated from the etching solution to control the length of the period during which the specific gravity value is changed.

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

the method further includes a step of determining the length of the specific gravity change period based on the size of a device manufactured using the substrate.

7. The substrate processing method according to any one of claims 1 to 3,

the method further includes a step of determining the first target value and the second target value based on a size of a device manufactured using the substrate.

8. A substrate processing apparatus for etching a substrate having an oxide film and a nitride film alternately stacked with an etching solution containing phosphoric acid,

the disclosed device is provided with:

a treatment tank for storing the etching solution;

a substrate holding unit for holding the substrate in the etching solution in the processing bath;

a parameter control unit that controls a parameter for varying a physical quantity corresponding to a concentration of the phosphoric acid in the etching solution so that the physical quantity becomes a target value; and

a changing unit that changes the target value from a first target value to a second target value lower than the first target value during the etching process of the substrate,