Substrate processing method and substrate processing apparatus

Abstract

A substrate processing method and a substrate processing apparatus are provided. The substrate processing method is a method of etching a substrate (W) having a silicon oxide film (Ma) and a silicon nitride film (Mb) alternately laminated with an etching liquid (E) containing phosphoric acid in a processing tank (3). The substrate processing method includes a step (S1) of immersing the substrate (W) in the etching liquid (E), and a step (S2) of changing a silicon concentration of the etching liquid (E) by supplementing the etching liquid (E) in the processing tank (3) with phosphoric acid in etching the substrate (W).

Description

TECHNICAL FIELD

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

[0002] A substrate processing apparatus that etches a substrate having a laminated structure in which silicon oxide films and silicon nitride films are alternately laminated is known. For example, in Patent Literature 1, a batch substrate processing apparatus that etches a substrate with an etching liquid containing phosphoric acid is disclosed. Specifically, the substrate processing apparatus of Patent Literature 1 removes silicon nitride films mainly by selectively etching silicon nitride films among silicon oxide films and silicon nitride films.

[0003] [BACKGROUND ART LITERATURE]

[0004] [PATENT LITERATURE]

[0005] [Patent Literature 1] Japanese Patent Laid-Open No. 2020-47886 SUMMARY

[0006] [PROBLEMS TO BE SOLVED BY THE INVENTION]

[0007] The substrate processing apparatus of Patent Literature 1 is used for processing to provide a laminated structure in which a plurality of flat silicon oxide films are arranged in a comb shape after etching, since the silicon oxide films are not substantially etched. However, it is desired to process a substrate into a complex shape by miniaturization and high integration of semiconductor devices.

[0008] The present application has been achieved in view of the above-described problems, and has an object to provide a substrate processing method and a substrate processing apparatus that can process a substrate into a more complex shape.

[0009] [TECHNICAL MEANS FOR SOLVING THE PROBLEMS]

[0010] According to an aspect of the present application, a substrate processing method is a method of etching a substrate having silicon oxide films and silicon nitride films alternately laminated with an etching liquid containing phosphoric acid in a processing tank. The substrate processing method includes a step of immersing the substrate in the etching liquid, and a step of changing a silicon concentration of the etching liquid by replenishing the etching liquid with phosphoric acid during etching of the substrate.

[0011] In one embodiment, in the step of changing the silicon concentration of the etching liquid, a replenishment flow rate of the phosphoric acid replenished to the etching liquid is controlled on the basis of a set value of the replenishment flow rate of the phosphoric acid set in accordance with a configuration of a semiconductor device manufactured using the substrate.

[0012] In one embodiment, in the step of changing the silicon concentration of the etching liquid, a replenishment flow rate of the phosphoric acid is controlled on the basis of a silicon concentration of the etching liquid measured during etching of the substrate.

[0013] In one embodiment, in the step of changing the silicon concentration of the etching liquid, the silicon-containing liquid containing silicon is supplied to the phosphoric acid supplied to the etching liquid.

[0014] In one embodiment, in the step of changing the silicon concentration of the etching liquid, the supply flow rate of the silicon-containing liquid to the phosphoric acid is controlled on the basis of a set value of the supply flow rate of the silicon-containing liquid set in accordance with the configuration of a semiconductor device manufactured using the substrate.

[0015] In one embodiment, in the step of changing the silicon concentration of the etching liquid, the supply flow rate of the silicon-containing liquid is controlled on the basis of the silicon concentration of the etching liquid measured during etching of the substrate.

[0016] In one embodiment, the configuration of the semiconductor device indicates the gap size between the silicon oxide films adjacent in the stacking direction in the semiconductor device.

[0017] According to another aspect of the present application, a substrate processing apparatus etches a substrate having silicon oxide films and silicon nitride films alternately stacked, with an etching liquid containing phosphoric acid. The substrate processing apparatus includes a processing tank, a substrate holding portion, a phosphoric acid supply mechanism, and a control portion. The processing tank stores the etching liquid. The substrate holding portion holds the substrate in the etching liquid stored in the processing tank. The phosphoric acid supply mechanism supplies phosphoric acid to the etching liquid in the processing tank. The control portion controls the phosphoric acid supply mechanism to change the silicon concentration of the etching liquid during etching of the substrate.

[0018] In one embodiment, the control portion controls the phosphoric acid supply mechanism during etching of the substrate on the basis of a set value of the supply flow rate of phosphoric acid set in accordance with the configuration of a semiconductor device manufactured using the substrate.

[0019] In one embodiment, the substrate processing apparatus further includes a silicon concentration meter that measures the silicon concentration of the etching liquid. The control portion controls the phosphoric acid supply mechanism during etching of the substrate on the basis of the silicon concentration measured by the silicon concentration meter during etching of the substrate.

[0020] In one embodiment, the substrate processing apparatus further includes a silicon supply mechanism. The silicon supply mechanism supplies a silicon-containing liquid containing silicon to the phosphoric acid supplied to the etching liquid.

[0021] In one embodiment, the control portion controls the silicon supply mechanism during etching of the substrate on the basis of a set value of the supply flow rate of the silicon-containing liquid set in accordance with the configuration of a semiconductor device manufactured using the substrate.

[0022] In one embodiment, the substrate processing apparatus further includes a silicon concentration meter that measures the silicon concentration of the etching solution. The control unit controls the silicon supply mechanism during etching of the substrate based on the silicon concentration measured by the silicon concentration meter during etching of the substrate.

[0023] In one embodiment, the configuration of the semiconductor device indicates a gap size between the silicon oxide films adjacent in a stacking direction in the semiconductor device.

[0024] [Effects of Invention]

[0025] According to the substrate processing method and the substrate processing apparatus of the present application, a substrate can be processed into a special shape. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 (a) and (b) are diagrams showing a substrate processing apparatus of Embodiment 1 of the present application.

[0027] Figure 2 is a cross-sectional view showing a configuration of the substrate processing apparatus of Embodiment 1 of the present application.

[0028] Figure 3 is a diagram showing a phosphoric acid replenishment mechanism included in the substrate processing apparatus of Embodiment 1 of the present application.

[0029] Figure 4 is a flowchart showing a substrate processing method of Embodiment 1 of the present application.

[0030] Figure 5 is a diagram showing an example of a change in silicon concentration during etching processing of the substrate processing apparatus of Embodiment 1 of the present application.

[0031] Figure 6 is a diagram showing an example of a shift in phosphoric acid replenishment flow rate during etching processing of the substrate processing apparatus of Embodiment 1 of the present application.

[0032] Figure 7 is a diagram showing a substrate before etching by the substrate processing apparatus of Embodiment 1 of the present application.

[0033] Figure 8 is a diagram showing a substrate after etching by the substrate processing apparatus of Embodiment 1 of the present application.

[0034] Figure 9 is a block diagram showing a configuration of a control device included in the substrate processing apparatus of Embodiment 1 of the present application.

[0035] Figure 10 is a diagram showing a first to third example of a change in silicon concentration during etching processing of the substrate processing apparatus of Embodiment 1 of the present application.

[0036] Figure 11 FIG. 1 is a graph showing a first example of the progress of the phosphoric acid replenishment flow rate during etching treatment by the substrate processing apparatus of Embodiment 1 of the present application.

[0037] Figure 12 FIG. 2 is a graph showing a first example of a substrate after etching by the substrate processing apparatus of Embodiment 1 of the present application.

[0038] Figure 13 FIG. 3 is a graph showing a second example of a substrate after etching by the substrate processing apparatus of Embodiment 1 of the present application.

[0039] Figure 14 FIG. 4 is a graph showing a third example of a substrate after etching by the substrate processing apparatus of Embodiment 1 of the present application.

[0040] Figure 15 FIG. 5 is a graph showing a fourth example of the variation of the silicon concentration during etching treatment by the substrate processing apparatus of Embodiment 1 of the present application.

[0041] Figure 16 FIG. 6 is a graph showing a fourth example of a substrate after etching by the substrate processing apparatus of Embodiment 1 of the present application.

[0042] Figure 17 FIG. 7 is a sectional view showing the configuration of the substrate processing apparatus of Embodiment 2 of the present application.

[0043] Figure 18 FIG. 8 is a sectional view showing the configuration of the substrate processing apparatus of Embodiment 3 of the present application.

[0044] Figure 19 FIG. 9 is a graph showing the phosphoric acid replenishment mechanism and the silicon supply mechanism included in the substrate processing apparatus of Embodiment 3 of the present application.

[0045] Figure 20 FIG. 10 is a graph showing a first example of the variation of the silicon concentration during etching treatment by the substrate processing apparatus of Embodiment 3 of the present application.

[0046] Figure 21 FIG. 11 is a graph showing a first example of the progress of the silicon supply flow rate during etching treatment by the substrate processing apparatus of Embodiment 3 of the present application.

[0047] Figure 22 FIG. 12 is a graph showing a first example of a substrate after etching by the substrate processing apparatus of Embodiment 3 of the present application.

[0048] Figure 23 FIG. 13 is a graph showing a second example of a substrate after etching by the substrate processing apparatus of Embodiment 3 of the present application.

[0049] Figure 24 FIG. 3 is a view showing a third example of a substrate after etching by the substrate processing apparatus of Embodiment 3 of the present application. DETAILED DESCRIPTION

[0050] Hereinafter, with reference to the drawings ( Figures 1-24 ), the embodiments of the substrate processing method and the substrate processing apparatus of the present application will be described. However, the present application is not limited to the following embodiments. In addition, sometimes the description is appropriately omitted for the parts described repeatedly. Further, in the drawings, the same reference numerals are applied to the same or equivalent parts, and the description is not repeated.

[0051] In the present specification, for easy understanding, sometimes the X direction, the Y direction and the Z direction orthogonal to each other are described. Typically, the X direction and the Y direction are parallel to the horizontal direction, and the Z direction is parallel to the vertical direction. However, it is not intended to limit the directions when the substrate processing method of the present application is performed, and the directions when the substrate processing apparatus of the present application is used, by defining these directions.

[0052] The "substrate" of the embodiments of the present application can be applied to various substrates such as a semiconductor wafer, a glass substrate for a reticle, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a substrate for a FED (Field Emission Display), a substrate for an optical disc, a substrate for a magnetic disc, and a substrate for a magneto-optical disc. Hereinafter, the embodiments of the present application will be mainly described with respect to the substrate processing method and the substrate processing apparatus for processing of a disc-shaped semiconductor wafer, but can be equally applied to processing of the various substrates exemplified above. Further, the various shapes can be applied to the shape of the substrate.

[0053] [Embodiment 1]

[0054] Hereinafter, Embodiment 1 of the present application will be described with reference to the drawings ( Figures 1-16 ). First, the substrate processing apparatus 100 of the present embodiment will be described with reference to Figure 1 (a) and Figure 1 (b). The substrate processing apparatus 100 of the present embodiment is a batch etching apparatus. Therefore, the substrate processing apparatus 100 etches a plurality of substrates W at a time. For example, the substrate processing apparatus 100 etches a plurality of substrates W in a batch unit. One batch, for example, contains 25 substrates W.

[0055] Figure 1 (a) and Figure 1 (b) are views showing the substrate processing apparatus 100 of the present embodiment. In detail, Figure 1 (a) shows the substrate processing apparatus 100 before the substrates W are put into the processing tank 3. Figure 1 (b) shows the substrate processing apparatus 100 after the substrates W are put into the processing tank 3. As shown inFigure 1 (a) and Figure 1 As shown in (b), the substrate processing apparatus 100 includes a processing tank 3, a control device 110, a lifting unit 120, and a substrate holding unit 130.

[0056] Processing tank 3 stores etching solution E. Etching solution E contains phosphoric acid (H3PO4) and silicon. Etching solution E may also contain a diluent. The diluent may be, for example, DIW (Deionized Water). DIW is a type of pure water. The diluent may also be carbonated water, electrolyzed ionized water, hydrogen water, ozone water, or hydrochloric acid water with a dilution concentration (e.g., approximately 10 ppm to 100 ppm). Additionally, etching solution E may contain additives different from those used for silicon.

[0057] The processing tank 3 has an inner tank 31 and an outer tank 32. The outer tank 32 surrounds the inner tank 31. In other words, the processing tank 3 has a double-layer tank structure. Both the inner tank 31 and the outer tank 32 have upward-opening upper openings.

[0058] Both the inner tank 31 and the outer tank 32 store etching solution E. The inner tank 31 houses multiple substrates W. Specifically, multiple substrates W held in the substrate holding portion 130 are housed in the inner tank 31. The multiple substrates W are immersed in the etching solution E within the inner tank 31 by being housed in the inner tank 31.

[0059] The substrate holding section 130 holds multiple substrates W within the etching solution E of the processing tank 3 (inner tank 31). Specifically, the substrate holding section 130 has multiple holding rods 131 and a body plate 132. The body plate 132 is a plate-shaped component that extends in the vertical direction (Z direction). The multiple holding rods 131 extend from one main surface of the body plate 132 in the horizontal direction (Y direction). In this embodiment, the substrate holding section 130 has three holding rods 131 (see reference). Figure 2 ).

[0060] Multiple substrates W are held by multiple holding rods 131. Specifically, the multiple substrates W are held in an upright (vertical) position by the multiple holding rods 131, with their lower edges abutting against the multiple holding rods 131. The multiple substrates W held by the substrate holding portion 130 are arranged at intervals along the Y direction. That is, the multiple substrates W are arranged in a row along the Y direction. Furthermore, each of the multiple substrates W is held in the substrate holding portion 130 in an orientation that is approximately parallel to the XZ plane.

[0061] The control device 110 controls the operation of each part of the substrate processing apparatus 100. For example, the control device 110 controls the operation of the lifting unit 120. The lifting unit 120, controlled by the control device 110, causes the substrate holding unit 130 to rise and fall. By raising and lowering the substrate holding unit 130, the substrate holding unit 130 moves vertically upwards or downwards while holding multiple substrates W. The lifting unit 120 has a drive source and a lifting mechanism; the drive source drives the lifting mechanism to raise and lower the substrate holding unit 130. The drive source may include, for example, an engine. The lifting mechanism may include, for example, a rack and pinion mechanism or a ball screw.

[0062] More specifically, the lifting unit 120 positions the substrate holding unit 130 in the processing position. Figure 1 (b) shows the position and the retreat position ( Figure 1 It rises and falls between the positions shown in (a). Figure 1 As shown in (b), if the substrate holding section 130, while holding multiple substrates W, descends vertically downwards (in the Z direction) and moves to the processing position, then the multiple substrates W are placed into the processing tank 3. That is, the multiple substrates W held in the substrate holding section 130 move into the inner tank 31. As a result, the multiple substrates W are immersed in the etching solution E within the inner tank 31 and etched by the etching solution E. On the other hand, as... Figure 1 As shown in (a), when the substrate holding part 130 moves to the retracted position, the plurality of substrates W held in the substrate holding part 130 move above the processing tank 3 and are lifted from the etching solution E.

[0063] Next, refer to Figure 2 The configuration of the substrate processing apparatus 100 in this embodiment will be explained. Figure 2 This is a cross-sectional view showing the configuration of the substrate processing apparatus 100 according to this embodiment. Figure 2 As shown, the control device 110 includes a control unit 111 and a storage unit 112.

[0064] The control unit 111 may also include a processor. For example, the control unit 111 may include a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 111 controls the operation of each part of the substrate processing apparatus 100 based on computer programs or data stored in the storage unit 112. Alternatively, the control unit 111 may include a general-purpose computer or a special-purpose computer. Both general-purpose and special-purpose computers include integrated circuits. Integrated circuits constitute logic circuits.

[0065] Storage unit 112 stores data and computer programs. The data includes process data. The process data represents multiple processes. Each process defines the processing content and order of the substrate W. Storage unit 112 has a main storage device. The main storage device is, for example, a semiconductor memory. The main storage device includes, for example, ROM (Read Only Memory) and RAM (Random Access Memory). Storage unit 112 may also have an auxiliary storage device. The auxiliary storage device includes, for example, at least one of a semiconductor memory and a hard disk drive. Storage unit 112 may also include removable media.

[0066] refer to Figure 2 The configuration of the substrate processing apparatus 100 in this embodiment will be further explained. For example... Figure 2 As shown, the substrate processing apparatus 100 also includes a phosphoric acid replenishment mechanism 4, a diluent supply mechanism 5, a foaming section 7, an etching solution circulation section 8, and an automatic cover 21.

[0067] The automatic cover 21 opens and closes the upper opening of the processing tank 3. Specifically, the automatic cover 21 opens and closes the upper opening of the inner tank 31 and the upper opening of the outer tank 32. In this embodiment, the automatic cover 21 has a first cover plate 22 and a second cover plate 23. The first cover plate 22 opens and closes freely with respect to the upper opening of the processing tank 3. The second cover plate 23 opens and closes freely with respect to the upper opening of the processing tank 3. The automatic cover 21 opens and closes in a double-opening manner through the first cover plate 22 and the second cover plate 22.

[0068] In detail, the first cover plate 22 is freely rotatable about a 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 cover plate 22 that is opposite to the center side of the automatic cover 21. The second cover plate 23 is freely rotatable about a 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 cover plate 23 that is opposite to the center side of the automatic cover 21.

[0069] Control device 110 (control unit 111) moves substrate holding unit 130 from the retracted position. Figure 1 (a) The position shown in the image is moved to the processing position. Figure 1 When in position (b), the automatic cover 21 is in the open state. By opening the automatic cover 21, the upper opening of the processing tank 3 is open, allowing the substrate W to be inserted into the processing tank 3 (inner tank 31). During the etching process of the substrate W, the control device 110 (control unit 111) closes the automatic cover 21. By closing the automatic cover 21, the upper opening of the processing tank 3 is closed. As a result, the interior of the processing tank 3 becomes a sealed space.

[0070] The control device 110 (the control section 111) moves the substrate holding section 130 from the processing position (the position shown in (b)) to the retreat position (the position shown in (a)) while setting the automatic cover 21 to the open state. By setting the automatic cover 21 to the open state, the upper opening of the processing tank 3 is set to the open state, and the substrate W can be lifted from the processing tank 3 (the inner tank 31). Figure 1 Figure 1 (a) shown) to the retreat position (the position shown in (a)), the control device 110 (the control section 111) sets the automatic cover 21 to the open state. By setting the automatic cover 21 to the open state, the upper opening of the processing tank 3 is set to the open state, and the substrate W can be lifted from the processing tank 3 (the inner tank 31).

[0071] Next, the phosphoric acid replenishing mechanism 4 will be described with reference to Figure 2 The phosphoric acid replenishing mechanism 4 replenishes the etching liquid E in the processing tank 3 with phosphoric acid. In the present embodiment, the phosphoric acid replenished by the phosphoric acid replenishing mechanism 4 is fresh liquid. Therefore, the phosphoric acid replenished by the phosphoric acid replenishing mechanism 4 does not contain silicon.

[0072] The control device 110 (the control section 111) changes the silicon concentration C of the etching liquid E by controlling the phosphoric acid replenishing mechanism 4 during etching of the substrate W. Specifically, the control section 111 changes the silicon concentration C of the etching liquid E from the first silicon concentration Cl to the second silicon concentration C2 during etching of the substrate W. Here, the first silicon concentration Cl indicates the silicon concentration C at the start of the etching process. The second silicon concentration C2 is a concentration different from the first silicon concentration Cl, and is, for example, greater than the first silicon concentration Cl.

[0073] In detail, when the substrate W is immersed in the etching liquid E, the silicon nitride film Mb (see FIG. 7) contained in the substrate W reacts with the phosphoric acid and etches the silicon nitride film Mb. At this time, silicon is generated as a reaction product. The generated silicon is precipitated in the etching liquid E. Therefore, in the case where the etching liquid E is not replenished with phosphoric acid during etching of the substrate W, the silicon concentration of the etching liquid E increases at a certain rate until the silicon nitride film Mb is removed. In contrast, in the present embodiment, the phosphoric acid replenishing mechanism 4 appropriately replenishes the etching liquid E with phosphoric acid during etching of the substrate W, and the silicon concentration C of the etching liquid E is controlled.

[0074] In the present embodiment, the phosphoric acid replenishing mechanism 4 has a phosphoric acid supply nozzle 41 and a phosphoric acid supply pipe 42. The phosphoric acid supply nozzle 41 supplies phosphoric acid to the processing tank 3. The phosphoric acid supply pipe 42 circulates phosphoric acid to the phosphoric acid supply nozzle 41. The phosphoric acid supply nozzle 41 is an example of a phosphoric acid supply section.

[0075] ​More specifically, the phosphoric acid supply nozzle 41 is disposed above the processing tank 3. The phosphoric acid supply nozzle 41 is a hollow tubular member. A plurality of ejection 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 plurality of ejection holes of the phosphoric acid supply nozzle 41 are formed at equal intervals in the Y direction. When the phosphoric acid supply nozzle 41 is supplied with phosphoric acid via the phosphoric acid supply pipe 42, the phosphoric acid is ejected from the plurality of ejection holes of the phosphoric acid supply nozzle 41 toward the processing tank 3. As a result, the processing tank 3 is supplied with phosphoric acid. In the present embodiment, the phosphoric acid supply nozzle 41 is disposed above the outer tank 32. Therefore, the phosphoric acid is ejected from the phosphoric acid supply nozzle 41 toward the outer tank 32, and the outer tank 32 is supplied with phosphoric acid.

[0076] Next, the diluent supply mechanism 5 will be described with reference to Figure 2 to FIG. 6. The diluent supply mechanism 5 supplies the processing tank 3 with diluent. As a result, the etching solution E in the processing tank 3 is supplied with diluent. In detail, the diluent supply mechanism 5 has a diluent supply nozzle 51 and a diluent supply pipe 52.

[0077] The diluent supply nozzle 51 is disposed above the processing tank 3. The diluent supply nozzle 51 is a hollow tubular member. A plurality of ejection 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 ejection holes of the diluent supply nozzle 51 are formed at equal intervals in the Y direction.

[0078] The diluent supply pipe 52 causes diluent to flow to the diluent supply nozzle 51. When the diluent supply nozzle 51 is supplied with diluent via the diluent supply pipe 52, the diluent is ejected from the plurality of ejection holes of the diluent supply nozzle 51.

[0079] The etching solution E is heated. For example, the temperature of the etching solution E is 120°C or higher and 160°C or lower. Therefore, the moisture contained in the etching solution E evaporates. Diluent is appropriately supplied to the etching solution E to maintain the concentration value or the specific gravity value of the phosphoric acid in the etching solution E at a target value.

[0080] Next, the bubbling section 7 will be described with reference to Figure 2 to FIG. 7. The bubbling section 7 supplies bubbles to the plurality of substrates W immersed in the etching solution E in the inner tank 31. In detail, the bubbling section 7 has a plurality of gas supply nozzles 71 and a gas supply pipe 72. In addition, in the present embodiment, the bubbling section 7 has two gas supply nozzles 71, but the bubbling section 7 can have one gas supply nozzle 71 or three or more gas supply nozzles 71.

[0081] 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 in a manner to be located below the plurality of substrates W immersed in the etching solution E in the inner tank 31.

[0082] The gas supply nozzles 71 are each a hollow tubular member. In each gas supply nozzle 71, a plurality of discharge holes are formed. In the present embodiment, the gas supply nozzles 71 extend in the Y direction. The plurality of discharge holes of the gas supply nozzles 71 are formed at equal intervals in the Y direction.

[0083] By blowing gas out of each discharge hole of each gas supply nozzle 71, bubbles are supplied to the plurality of substrates W immersed in the etching liquid E in the inner tank 31. The gas is, for example, an inert gas. Specifically, the gas can be nitrogen.

[0084] The gas supply piping 72 causes gas to flow to the plurality of gas supply nozzles 71. The gas supply piping 72 supplies bubbles to the plurality of substrates W immersed in the etching liquid E in the inner tank 31 by causing gas to flow. As a result, the non-uniformity of the silicon concentration C in the etching liquid E is suppressed, and the substrates W are etched uniformly.

[0085] Next, the etching liquid circulation section 8 will be described with reference to Figure 2 The etching liquid circulation section 8 circulates the etching liquid E between the outer tank 32 and the inner tank 31. Specifically, the etching liquid circulation section 8 has a plurality of etching liquid supply nozzles 81, a circulation piping 82, a circulation pump 83, a circulation heater 84, and a circulation filter 85. In the present embodiment, the etching liquid circulation section 8 has two etching liquid supply nozzles 81, but the etching liquid circulation section 8 can have one etching liquid supply nozzle 81 or three or more etching liquid supply nozzles 81.

[0086] The plurality of etching liquid supply nozzles 81 are disposed on the bottom side of the inner tank 31. Each etching liquid supply nozzle 81 is a hollow tubular member. In each etching liquid supply nozzle 81, a plurality of discharge holes are formed. In the present embodiment, the etching liquid supply nozzles 81 extend in the Y direction. The plurality of discharge holes of the etching liquid supply nozzles 81 are formed at equal intervals in the Y direction.

[0087] One end of the circulation piping 82 is connected to the outer tank 32, and the etching liquid E flows from the outer tank 32 into the circulation piping 82. The circulation piping 82 causes the etching liquid E to flow to the plurality of etching liquid supply nozzles 81.

[0088] A circulation pump 83 is installed in the circulation piping 82. The circulation pump 83 drives the etching solution E by the pressure of the fluid flowing through the circulation piping 82. As a result, the etching solution E flows from the outer tank 32 to the inner tank 31 via the circulation piping 82. Specifically, the etching solution E flows through the circulation piping 82 and is sprayed into the inner tank 31 from the nozzle of the etching solution supply nozzle 81. That is, the etching solution E is supplied into the inner tank 31 from the etching solution supply nozzle 81. Furthermore, by spraying the etching solution E into the inner tank 31 from the etching solution supply nozzle 81, the etching solution E flows from the inner tank 31 to the outer tank 32 via the upper end face of the side wall of the inner tank 31.

[0089] A circulating heater 84 and a circulating filter 85 are installed in the circulating piping 82. The circulating heater 84 heats the etching solution E flowing in the circulating piping 82. Specifically, the circulating heater 84 heats the etching solution E at a temperature between 120°C and 160°C. The circulating filter 85 removes foreign matter from the etching solution E flowing in the circulating piping 82.

[0090] Next, refer to Figure 3 This explains the composition of the phosphate supplementation mechanism 4. Figure 3 This diagram illustrates the phosphoric acid replenishment mechanism 4 included in the substrate processing apparatus 100 of this embodiment. Figure 3 As shown, the phosphoric acid replenishment mechanism 4 also has an on / off valve 43. The on / off valve 43 is installed in the phosphoric acid supply piping 42.

[0091] The on / off valve 43 is, for example, a solenoid valve. The on / off valve 43 opens and closes the flow path of the phosphoric acid supply pipe 42, controlling the flow of phosphoric acid within the phosphoric acid supply pipe 42. Specifically, when the on / off valve 43 is open, phosphoric acid flows through the phosphoric acid supply pipe 42 to the phosphoric acid supply nozzle 41. As a result, phosphoric acid is ejected from the phosphoric acid supply nozzle 41. On the other hand, when the on / off valve 43 is closed, the flow of phosphoric acid is cut off, stopping the ejection of phosphoric acid from the phosphoric acid supply nozzle 41.

[0092] The on / off valve 43 is controlled by the control device 110 (control unit 111). During the etching of the substrate W, the control unit 111 opens and closes the on / off valve 43, causing a change in the silicon concentration C of the etching solution E. Specifically, the control unit 111 opens and closes the on / off valve 43 during the etching of the substrate W, controlling the flow rate of phosphoric acid replenished to the etching solution E, i.e., the phosphoric acid replenishment flow rate F. As a result, the silicon concentration C of the etching solution E changes.

[0093] In detail, the phosphoric acid replenishment mechanism 4 also includes a flow meter 44. The flow meter 44 is installed in the phosphoric acid supply pipe 42. The flow meter 44 measures the flow rate of phosphoric acid flowing in the phosphoric acid supply pipe 42. The flow meter 44 outputs a signal indicating the measurement result to the control unit 111. The flow meter 44 may be, for example, an totalizing flow meter.

[0094] The storage section 112 stores a set value of the phosphoric acid replenishment flow rate F. The control section 111 controls the opening and closing of the on-off valve 43 based on the flow rate of the phosphoric acid measured by the flow meter 44 and the set value of the phosphoric acid replenishment flow rate F. As a result, the flow rate of the phosphoric acid replenished to the etching solution E (the phosphoric acid replenishment flow rate F) is controlled based on the flow rate of the phosphoric acid measured by the flow meter 44 and the set value of the phosphoric acid replenishment flow rate F.

[0095] Next, a substrate processing method according to the present embodiment will be described with reference to Figure 4 Figure 4 is a flowchart showing the substrate processing method according to the present embodiment. The substrate processing method according to the present embodiment can also be implemented by the substrate processing apparatus 100 described with reference to Figures 1-3 Figures 1-3 Next, a substrate processing method implemented by the substrate processing apparatus 100 described with reference to Figure 4

[0096] First, when the etching processing of the substrate W is started, the plurality of substrates W is dipped in the etching solution E (step S1). Specifically, the substrate holding section 130 is moved to the processing position. As a result, the plurality of substrates W held in the substrate holding section 130 is housed in the inner tank 31, and the plurality of substrates W is dipped in the etching solution E in the inner tank 31. At this time, the silicon concentration C of the etching solution E housed in the processing tank 3 is the first silicon concentration Cl.

[0097] When the plurality of substrates W is dipped in the etching solution E, the substrate W is etched by the etching solution E. The control section 111 changes the silicon concentration C of the etching solution E during the etching of the substrate W. Specifically, the control section 111 controls the on-off valve 43 of the phosphoric acid replenishment mechanism 4 to replenish the phosphoric acid to the etching solution E in the processing tank 3, thereby changing the silicon concentration C of the etching solution E (step S2). More specifically, the control section 111 changes the silicon concentration C of the etching solution E from the first silicon concentration Cl to the second silicon concentration C2 by replenishing the phosphoric acid.

[0098] When a certain time elapses after the plurality of substrates W is dipped in the etching solution E, the plurality of substrates W is lifted from the etching solution E (step S3), Figure 4 the etching processing ends as shown in

[0099] Next, an example of the change in the silicon concentration C will be described with reference to Figures 1-6 Figure 5 is a graph showing an example of the change in the silicon concentration C of the etching solution E in the substrate processing apparatus 100 according to the present embodiment. Figure 6 ​​​​This is a diagram illustrating an example of the shift in phosphoric acid replenishment flow rate F during the etching process of the substrate processing apparatus 100 in this embodiment.

[0100] Figure 5 In the graph, the vertical axis represents silicon concentration C, and the horizontal axis represents processing time t. Furthermore, Figure CP1 (solid line) shows an example of the change in silicon concentration C when phosphoric acid replenishment mechanism 4 replenishes phosphoric acid to etching solution E. Figure CP2 (dashed line) shows the change in silicon concentration C when phosphoric acid is not replenished to etching solution E. Figure 6 In the graph, the vertical axis represents the phosphoric acid replenishment flow rate F, and the horizontal axis represents the processing time t. Furthermore, graph FP shows an example of the shift in the phosphoric acid replenishment flow rate (phosphoric acid replenishment flow rate F) of the phosphoric acid replenishment mechanism 4 to the etching solution E.

[0101] like Figure 5 As shown, the silicon concentration C at the etching start time ts is the first silicon concentration C1, and the silicon concentration C at the etching end time te is the second silicon concentration C2. Figure 5 In the example shown, the first silicon concentration C1 is low, and the second silicon concentration C2 is high. For example, the low concentration is between 40 ppm and 50 ppm when the temperature of the etching solution E is 160°C. The high concentration is 60 ppm when the temperature of the etching solution E is 160°C.

[0102] After immersing multiple substrates W in the etching solution E to begin the etching process, the silicon concentration C increases. As shown in Figure CP2, during the etching of substrates W, without replenishing phosphoric acid to the etching solution E, the silicon concentration C of the etching solution E increases sharply. In contrast, in this embodiment, during the etching of substrates W, the phosphoric acid replenishment mechanism 4 replenishes phosphoric acid to the etching solution E, diluting the silicon concentration C through the replenished phosphoric acid. As a result, as shown in Figure CP1, the silicon concentration C increases slowly.

[0103] For example, such as Figure 6 As shown in Figure FP, when the etching process begins, the control unit 111 drives the on / off valve 43 of the phosphoric acid replenishment mechanism 4 to maintain the phosphoric acid replenishment flow rate F at a first replenishment flow rate F1 (a fixed value). As a result, as shown in Figure 5, the silicon concentration C increases slowly. Furthermore, the first replenishment flow rate F1 represents the phosphoric acid replenishment flow rate F at the start of etching of the substrate W. Figure 6 In the example shown, the first supplemental flow rate F1 is set to a flow rate that slowly increases the silicon concentration C from a low concentration to a high concentration.

[0104] like Figure 5 As shown, when the silicon concentration C increases to near the second silicon concentration C2, as... Figure 6 As shown, the control unit 111 drives the opening and closing valve 43 of the phosphoric acid replenishment mechanism 4 by increasing the phosphoric acid replenishment flow rate F. As a result, as... Figure 5As shown, the silicon concentration C increases more slowly near the second silicon concentration C2.

[0105] like Figure 5 As shown, when the processing time t reaches time t1 near the etching end time te, the silicon concentration C reaches the second silicon concentration C2. At this time, the phosphoric acid replenishment flow rate F is as follows: Figure 6 As shown, the flow rate is increased to the second replenishment flow rate F2. After the phosphoric acid replenishment flow rate F reaches the second replenishment flow rate F2, the control unit 111 drives the opening and closing valve 43 of the phosphoric acid replenishment mechanism 4 to maintain the second replenishment flow rate F2. As a result, as shown... Figure 5 As shown, the silicon concentration C is maintained at the second silicon concentration C2. The second supplementary flow rate F2 is the flow rate that maintains the silicon concentration C at a fixed value.

[0106] Next, refer to Figure 7 The substrate W etched by the substrate processing apparatus 100 of this embodiment will be described. Figure 7 This is a diagram showing the substrate W before it is etched by the substrate processing apparatus 100 of this embodiment. The substrate W etched by the substrate processing apparatus 100 of this embodiment is used, for example, for three-dimensional flash memory (e.g., three-dimensional NAND (Not and) flash memory).

[0107] like Figure 7 As shown, the substrate W includes a base material S and a multilayer structure M. The base material S is a thin film unfolded in the XZ plane. The base material S contains, for example, silicon. The multilayer structure M is formed on the upper surface of the substrate S. The multilayer structure M is formed such that it extends from the upper surface of the base material S in the Y direction. The multilayer structure M has silicon oxide films Ma and silicon nitride films Mb alternately stacked along the Y direction. The silicon oxide films Ma are unfolded parallel to the upper surface of the base material S. The silicon nitride films Mb are unfolded parallel to the upper surface of the base material S.

[0108] The multilayer structure M has one or more recesses RE. The recesses RE extend from the upper surface of the multilayer structure M to the substrate S, and a portion of the upper surface of the substrate S is exposed from the recesses RE. Furthermore, the side surfaces of the silicon oxide film Ma and the silicon nitride film Mb are exposed from the interfaces of the recesses RE. The recesses RE function as trenches or holes, for example, when the substrate W is used in a semiconductor product.

[0109] Next, refer to Figure 7 and Figure 8 This describes the etching process of the substrate processing apparatus 100 in this embodiment. Figure 8 This is a diagram showing an example of a substrate W after being etched by the substrate processing apparatus 100 of this embodiment.

[0110] When the substrate W is immersed in the etching liquid E, the etching liquid E permeates the recess RE. As a result, the etching liquid E contacts the silicon oxide film Ma and the silicon nitride film Mb at the interface of the recess RE.

[0111] The etching amount (selectivity) of the etching liquid E to the silicon oxide film Ma and the silicon nitride film Mb can be controlled by the silicon concentration C of the etching liquid E under the condition that the temperature of the etching liquid E and the specific gravity value (concentration) of phosphoric acid are fixed. Specifically, in the case where the silicon concentration C of the etching liquid E is high, the etching amount of the silicon oxide film Ma is sufficiently small, and in the laminated structure M, almost only the silicon nitride film Mb is etched. On the other hand, in the case where the silicon concentration C of the etching liquid E is lower than the high concentration, the silicon oxide film Ma is etched together with the silicon nitride film Mb. The higher the silicon concentration C, the smaller the etching amount of the silicon oxide film Ma. In addition, the etching amount of the silicon nitride film Mb is substantially fixed regardless of the silicon concentration C.

[0112] For example, as explained with reference to Figure 5 and Figure 6 , in the case where the silicon concentration C is changed from the low concentration to the high concentration, at the initial stage of the etching process, since the silicon concentration C is low, the silicon oxide film Ma is etched together with the silicon nitride film Mb. Specifically, from the portion of the recess RE side which contacts the etching liquid E, the silicon oxide film Ma and the silicon nitride film Mb are sequentially etched. However, since the etching speed of the silicon nitride film Mb is faster than that of the silicon oxide film Ma, the etching amount of the silicon oxide film Ma is smaller than that of the silicon nitride film Mb.

[0113] After that, by slowly increasing the silicon concentration C, the portion of the silicon oxide film Ma which is farther from the recess RE contacts the etching liquid E with the higher silicon concentration C. As a result, as shown in Figure 8 , the width in the Y direction of the portion of the silicon oxide film Ma on the recess RE side becomes small, and the farther the portion is from the recess RE, the larger the width in the Y direction. Therefore, in the etched substrate W, the gap G between the silicon oxide films Ma adjacent in the laminated direction is wider closer to the recess RE and narrower farther from the recess RE.

[0114] Next, the configuration of the control device 110 is explained with reference to Figure 9 . Figure 9 is a block diagram showing the configuration of the control device 110 included in the substrate processing device 100 of the present embodiment. As shown in Figure 9 , the control device 110 further includes an input section 113.

[0115] Input unit 113 accepts data input from the operator. Input unit 113 is a user interface device operated by the operator. Input unit 113 inputs data corresponding to the operator's operation to control unit 111. Control unit 111 stores the data input by input unit 113 in storage unit 112. Input unit 113 may include, for example, a keyboard and a mouse. Input unit 113 may also not have a touch sensor.

[0116] The input unit 113 accepts input of the set value for the phosphoric acid replenishment flow rate F. Specifically, the operator operates the input unit 113 to input a set value corresponding to the structure of a semiconductor device manufactured using the substrate W processed by the substrate processing apparatus 100. For example, the operator inputs a set value corresponding to a reference... Figure 8 The size of the gap G described corresponds to the set value of the phosphoric acid replenishment flow rate F.

[0117] More specifically, the operator inputs data representing the relationship between the etching process time t and the phosphoric acid replenishment flow rate F, which serves as the setpoint for the phosphoric acid replenishment flow rate F. For example, the operator can also input data from reference... Figure 6 The data corresponding to the illustrated chart FP is used as the setpoint for the phosphoric acid replenishment flow rate F. Specifically, the operator inputs data representing the first replenishment flow rate F1, data representing the second replenishment flow rate F2, and data representing the time point when the first replenishment flow rate F1 changes to the second replenishment flow rate, which are used as the setpoint for the phosphoric acid replenishment flow rate F. The control unit 111 controls the opening and closing of the phosphoric acid replenishment mechanism 4's valve 43 based on the phosphoric acid flow rate measured by the flow meter 44 and the setpoint for the phosphoric acid replenishment flow rate F. As a result, the phosphoric acid replenishment flow rate F is as follows: Figure 6 The graph FP shows the shift. Therefore, the silicon concentration C of the etchant E is as follows: Figure 5 As shown in Figure CP1, the shape of the substrate W changes to become Figure 8 The shape shown.

[0118] Next, refer to Figures 1-14 Examples 1 to 3 illustrate the changes in silicon concentration C. Figure 10 These are the first to third examples showing the change in silicon concentration C during the etching process of the substrate processing apparatus 100 in this embodiment. Figure 11 The figures are the first to third examples showing the shift in phosphoric acid replenishment flow rate F during the etching process of the substrate processing apparatus 100 in this embodiment. Figures 12-14 The diagram shows the first to third examples of the substrate W after being etched by the substrate processing apparatus 100 of this embodiment.

[0119] Figure 10 In the figures, the vertical axis represents silicon concentration C, and the horizontal axis represents processing time t. Furthermore, charts CP11 to CP13 represent examples 1 through 3 of the variation in silicon concentration C, respectively. Figure 11In the diagram, the vertical axis represents the phosphoric acid replenishment flow rate F, and the horizontal axis represents the processing time t. Furthermore, charts FP1 to FP3 represent the first to third examples of the shift in the phosphoric acid replenishment flow rate (phosphoric acid replenishment flow rate F) supplied by the phosphoric acid replenishment mechanism 4 to the etching solution E.

[0120] like Figure 10 As shown, the second silicon concentration C2 (C21-C23) is different in examples 1 to 3 (Figures CP11-CP13). Specifically, the second silicon concentration C21 in example 1 (Figure CP11) is higher than the second silicon concentration C22 in example 2 (Figure CP12), and the second silicon concentration C22 in example 2 (Figure CP12) is higher than the second silicon concentration C23 in example 3 (Figure CP13). Figure 11 As shown, the first supplementary flow F1 (F11 to F13) of examples 1 to 3 (Figures FP1 to FP3) are different from each other. Specifically, the first supplementary flow F11 of example 1 (Figure FP1) is less than the first supplementary flow F12 of example 2 (Figure FP2), and the first supplementary flow F12 of example 2 (Figure FP2) is less than the first supplementary flow F13 of example 3 (Figure FP3).

[0121] like Figure 10 and Figure 11 As shown, the larger the first replenishment flow rate F1, the smaller the second silicon concentration C2. Furthermore, as shown in Figure 12… Figure 14 As shown, the lower the second silicon concentration C2, the wider the gap G. Specifically, the lower the second silicon concentration C2, the greater the etching amount of the silicon oxide film Ma. Therefore, the longer the contact time with the etchant E on the recess RE side, the greater the etching amount of the silicon oxide film Ma, and the wider the recess RE side of the gap G. For example, Figure 12 The substrate W shown in the first example is with Figure 13 Compared to the substrate W in the second example shown, the recess RE side of the gap G is narrower. Figure 13 The substrate W shown in the second example is with Figure 14 Compared to the substrate W in the third example shown, the recess RE side of the gap G is narrower.

[0122] Next, refer to Figure 15 and Figure 16 This is the fourth example illustrating the change in silicon concentration C. Figure 15 This is a fourth example of the change in silicon concentration C during the etching process of the substrate processing apparatus 100 in this embodiment. Figure 16 This is a diagram showing the fourth example of a substrate W etched by the substrate processing apparatus 100 of this embodiment.

[0123] Figure 15 In the graph, the vertical axis represents silicon concentration C, and the horizontal axis represents processing time t. Furthermore, chart CP14 shows the fourth example of the change in silicon concentration C.Figure 15 As shown, in the fourth example, the first silicon concentration Cl is higher than the second silicon concentration C2. Specifically, the first silicon concentration Cl is a high concentration, and the second silicon concentration C2 is a low concentration. In this case, at the initial stage of the etching process, since the silicon concentration C is a high concentration, the silicon nitride film Mb is etched almost exclusively in the stacked structure M. Thereafter, the silicon concentration C decreases slowly. As a result, as shown in FIG. 6B, the etching amount of the silicon oxide film Ma is greater on the side of the recess RE where the contact time with the etching liquid E is longer. As a result, the width in the Y direction of the portion of the silicon oxide film Ma on the side of the recess RE becomes smaller, and the farther the portion is from the recess RE, the greater the width in the Y direction. Figure 16 As shown, in the fourth example, the first silicon concentration Cl is higher than the second silicon concentration C2. Specifically, the first silicon concentration Cl is a high concentration, and the second silicon concentration C2 is a low concentration. In this case, at the initial stage of the etching process, since the silicon concentration C is a high concentration, the silicon nitride film Mb is etched almost exclusively in the stacked structure M. Thereafter, the silicon concentration C decreases slowly. As a result, as shown in FIG. 6B, the etching amount of the silicon oxide film Ma is greater on the side of the recess RE where the contact time with the etching liquid E is longer. As a result, the width in the Y direction of the portion of the silicon oxide film Ma on the side of the recess RE becomes smaller, and the farther the portion is from the recess RE, the greater the width in the Y direction.

[0124] The above has been described with reference to Figures 1-16 Embodiment 1 of the present application will be described. According to the present embodiment, the silicon concentration C of the etching liquid E can be varied during etching of the substrate W. Therefore, according to the present embodiment, the shape of the silicon oxide film Ma can be controlled, and the substrate W can be processed into a special shape.

[0125] [Embodiment 2]

[0126] Next, Embodiment 2 of the present application will be described with reference to Figure 17 However, matters different from Embodiment 1 will be described, and the description of matters common to Embodiment 1 will be omitted. Embodiment 2 differs from Embodiment 1 in that the substrate processing apparatus 100 is provided with a silicon concentration meter 86.

[0127] Figure 17 is a cross-sectional view showing the configuration of the substrate processing apparatus 100 of the present embodiment. As shown in Figure 17 The substrate processing apparatus 100 of the present embodiment is further provided with a silicon concentration meter 86. The silicon concentration meter 86 measures the silicon concentration C of the etching liquid E. The silicon concentration meter 86 outputs a signal indicating the measurement result to the control section 111.

[0128] In the present embodiment, the silicon concentration meter 86 is attached to the circulation piping 82. Therefore, the silicon concentration meter 86 measures the silicon concentration C of the etching liquid E circulating in the circulation piping 82. Specifically, the silicon concentration meter 86 is disposed on the downstream side (the inner tank 31 side) with respect to the circulation filter 85. Therefore, the silicon concentration meter 86 measures the silicon concentration C of the etching liquid E after removal of foreign matter. Thus, the accuracy of the measurement result of the silicon concentration C of the etching liquid E by the silicon concentration meter 86 can be improved.

[0129] In the present embodiment, the control section 111 controls the opening and closing valve 43 of the phosphoric acid replenishment mechanism 4 on the basis of the silicon concentration C measured by the silicon concentration meter 86 (see Figure 3In other words, the control section 111 controls the flow rate of phosphoric acid supplied from the phosphoric acid supply mechanism 4 to the etching liquid E (phosphoric acid supply flow rate F) based on the silicon concentration C measured by the silicon concentration meter 86.

[0130] More specifically, the control section 111 controls the phosphoric acid supply flow rate F based on the set value related to the silicon concentration C stored in the storage section 112 and the silicon concentration C measured by the silicon concentration meter 86.

[0131] In detail, the storage section 112 stores data indicating the relationship between the processing time t of the etching process and the silicon concentration C as the set value related to the silicon concentration C. Alternatively, the storage section 112 stores data indicating the relationship between the processing time t of the etching process and the rate of change of the silicon concentration C. For example, the storage section 112 can store the data corresponding to the graph CP1 explained above. In this case, the control section 111 controls the opening and closing of the opening and closing valve 43 of the phosphoric acid supply mechanism 4 in such a manner that the silicon concentration C measured by the silicon concentration meter 86 follows the change of the silicon concentration C indicated by the graph CP1. Figure 5 The graph CP1 explained above. In this case, the control section 111 controls the opening and closing of the opening and closing valve 43 of the phosphoric acid supply mechanism 4 in such a manner that the silicon concentration C measured by the silicon concentration meter 86 follows the change of the silicon concentration C indicated by the graph CP1. Figure 5 The graph CP1 explained above. In this case, the control section 111 controls the opening and closing of the opening and closing valve 43 of the phosphoric acid supply mechanism 4 in such a manner that the silicon concentration C measured by the silicon concentration meter 86 follows the change of the silicon concentration C indicated by the graph CP1. Figure 3 As a result, the shape of the substrate W becomes the shape indicated by the graph CP2. Figure 8 The graph CP2 explained above.

[0132] The embodiment 2 of the present application has been explained above with reference to Figure 17 According to the embodiment, the shape of the silicon oxide film Ma can be controlled, and the substrate W can be processed into a special shape.

[0133] [Embodiment 3]

[0134] Next, the embodiment 3 of the present application will be explained with reference to Figures 18-24 However, the matters different from the embodiments 1 and 2 will be explained, and the explanation related to the matters common to the embodiments 1 and 2 will be omitted. The embodiment 3 is different from the embodiments 1 and 2 in that the substrate processing apparatus 100 is provided with the silicon supply mechanism 45.

[0135] Figure 18 is a sectional view indicating the configuration of the substrate processing apparatus 100 of the present embodiment. As Figure 18 indicated in the drawing, the substrate processing apparatus 100 of the present embodiment is further provided with the silicon supply mechanism 45. The silicon supply mechanism 45 supplies the silicon-containing liquid containing silicon to the phosphoric acid supplied to the etching liquid E. In addition, the silicon-containing liquid is, for example, a suspension liquid containing silicon. Hereinafter, the phosphoric acid supplied to the etching liquid E will be sometimes referred to as "supplemental phosphoric acid".

[0136] Specifically, the silicon supply mechanism 45 has a silicon supply pipe 451. One end of the silicon supply pipe 451 is connected to the phosphoric acid supply pipe 42. The silicon supply pipe 451 causes the silicon-containing liquid to flow to the phosphoric acid supply pipe 42. Thus, the silicon-containing liquid is supplied to the replenished phosphoric acid flowing in the phosphoric acid supply pipe 42. As a result, the silicon-containing replenished phosphoric acid is ejected from the phosphoric acid supply nozzle 41 to the outer tank 32. Hereinafter, the silicon-containing replenished phosphoric acid is sometimes referred to as "silicon-containing phosphoric acid".

[0137] Next, the configuration of the silicon supply mechanism 45 will be described with reference to Figure 19 , shown in FIG. 8. Figure 19 is a view showing the phosphoric acid replenishment mechanism 4 and the silicon supply mechanism 45 included in the substrate processing apparatus 100 of the present embodiment. As shown in Figure 19 , the silicon supply mechanism 45 further has an on-off valve 452. The on-off valve 452 is installed in the silicon supply pipe 451. In addition, in the following description, the on-off valve 43 of the phosphoric acid replenishment mechanism 4 is sometimes referred to as "first on-off valve 43", and the on-off valve 452 of the silicon supply mechanism 45 is sometimes referred to as "second on-off valve 452".

[0138] The second on-off valve 452 is, for example, a solenoid valve. The second on-off valve 452 opens and closes the flow path of the silicon supply pipe 451, and controls the flow of the silicon-containing liquid flowing in the silicon supply pipe 451. Specifically, when the second on-off valve 452 is opened, the silicon-containing liquid flows to the phosphoric acid supply pipe 42 via the silicon supply pipe 451. As a result, the silicon-containing phosphoric acid is ejected from the phosphoric acid supply nozzle 41. On the other hand, when the second on-off valve 452 is closed, the flow of the silicon-containing liquid is cut off, and the supply of silicon (silicon-containing liquid) to the phosphoric acid flowing in the phosphoric acid supply pipe 42 is stopped.

[0139] The second on-off valve 452 is controlled by the control device 110 (control section 111). The control section 111 opens and closes the first on-off valve 43 and the second on-off valve 452 during etching of the substrate W, and changes the silicon concentration C of the etching liquid E. Specifically, the control section 111 opens and closes the second on-off valve 452 during etching of the substrate W, and controls the flow rate R of the silicon-containing liquid supplied to the replenished phosphoric acid, that is, the silicon supply flow rate. In addition, the control section 111 opens and closes the first on-off valve 43 during etching of the substrate W, and controls the flow rate of the silicon-containing phosphoric acid and the flow rate of the replenished phosphoric acid (fresh liquid).

[0140] Specifically, the silicon supply mechanism 45 further has a flowmeter 453. The flowmeter 453 is installed in the silicon supply pipe 451. The flowmeter 453 measures the flow rate of the silicon-containing liquid flowing in the silicon supply pipe 451. The flowmeter 453 outputs a signal indicating the measurement result to the control section 111. The flowmeter 453 can be, for example, an integrating flowmeter.

[0141] The storage section 112 stores a set value of the silicon supply flow rate R. The control section 111 controls the opening and closing of the 2nd on-off valve 452 on the basis of the flow rate of the silicon-containing liquid measured by the flowmeter 453 and the set value of the silicon supply flow rate R. In other words, the control section 111 controls the supply flow rate of the silicon-containing liquid supplied to the replenishing phosphoric acid (the silicon supply flow rate R) on the basis of the flow rate of the silicon-containing liquid measured by the flowmeter 453 and the set value of the silicon supply flow rate R.

[0142] Next, a first example to a third example of the change in the silicon concentration C will be described with reference to Figures 18-24 , respectively. Figure 20 are graphs showing the first example to the third example of the change in the silicon concentration C during etching processing by the substrate processing apparatus 100 of the present embodiment. Figure 21 are graphs showing the first example to the third example of the progress of the silicon supply flow rate R during etching processing by the substrate processing apparatus 100 of the present embodiment. Figures 22-24 are graphs showing the first example to the third example of the substrate W after etching by the substrate processing apparatus 100 of the present embodiment, respectively.

[0143] Figure 20 In the graph CP21, the vertical axis represents the silicon concentration C. The horizontal axis represents the processing time t. Further, the graph CP21 shows the first example of the change in the silicon concentration C. Figure 21 In the graph RP1, the vertical axis represents the silicon supply flow rate R. The horizontal axis represents the processing time t. Further, the graph RP1 shows the first example of the progress of the supply flow rate of the silicon-containing liquid (the silicon supply flow rate R).

[0144] As shown in the graph CP21, the silicon concentration C changes from the first silicon concentration Cl to the second silicon concentration C2 when etching the substrate W. Figure 20 In the example shown in the graph CP22, the second silicon concentration C2 represents a concentration higher than the first silicon concentration Cl. Figure 20 After starting the etching processing to immerse the plurality of substrates W in the etching liquid E, the silicon concentration C increases. In the first example to the third example, the length of time required for the silicon concentration C to change from the first silicon concentration Cl to the second silicon concentration C2 is different from one another. Hereinafter, the length of time required for the silicon concentration C to change from the first silicon concentration Cl to the second silicon concentration C2 will be referred to as the "silicon concentration change period".

[0145] Specifically, the silicon concentration change period (ts to tll) of the first example (the graph CP21) is shorter than the silicon concentration change period (ts to t21) of the second example (the graph CP22). In other words, the silicon concentration C of the first example reaches the second silicon concentration C2 at an earlier point in time than the silicon concentration C of the second example. Therefore, the rate of change of the silicon concentration C of the first example is greater than the rate of change of the silicon concentration C of the second example.

[0146]

[0147] ​The silicon concentration change period (ts ~ t21) of the second example (chart CP22) is shorter than the silicon concentration change period (ts ~ t31) of the third example (chart CP23). In other words, the silicon concentration C of the second example reaches the second silicon concentration C2 from the first silicon concentration Cl at an earlier time point than the third example. Therefore, the rate of change of the silicon concentration C of the second example is greater than the rate of change of the silicon concentration C of the third example.

[0148] As shown in Figure 21 , the silicon-containing liquid is supplied to the replenishing phosphoric acid from the start of etching (the etching start time ts). Therefore, the silicon-containing phosphoric acid is supplied to the etching liquid E from the start of etching (the etching start time ts). Specifically, the silicon supply mechanism 45 supplies the silicon-containing liquid to the replenishing phosphoric acid at a fixed supply flow rate when the plurality of substrates W are immersed in the etching liquid E at the start of the etching process, and stops the supply of the silicon-containing liquid when a prescribed time elapses.

[0149] As shown in charts RP1 to RP3, the length of time during which the silicon-containing liquid is supplied, that is, the silicon supply period, and the silicon supply flow rate R of the first to third examples are different from each other.

[0150] Specifically, the silicon supply period (ts ~ t11) of the first example (chart RP1) is shorter than the silicon supply period (ts ~ t21) of the second example (chart RP2), and the silicon supply flow rate Rl of the first example (chart RP1) is greater than the silicon supply flow rate R2 of the second example (chart RP2). As a result, as explained with reference to Figure 20 , the silicon concentration C of the first example reaches the second silicon concentration C2 from the first silicon concentration Cl at an earlier time point than the second example. Therefore, the rate of change of the silicon concentration C of the first example is greater than the rate of change of the silicon concentration C of the second example.

[0151] The silicon supply period (ts ~ t21) of the second example (chart RP2) is shorter than the silicon supply period (ts ~ t31) of the third example (chart RP3), and the silicon supply flow rate R2 of the second example (chart RP2) is greater than the silicon supply flow rate R3 of the third example (chart RP3). As a result, as explained with reference to Figure 20 , the silicon concentration C of the second example reaches the second silicon concentration C2 from the first silicon concentration Cl at an earlier time point than the third example. Therefore, the rate of change of the silicon concentration C of the second example is greater than the rate of change of the silicon concentration C of the third example.

[0152] In addition, after the end of the silicon supply period, in order to maintain the silicon concentration C at the second silicon concentration C2, new phosphoric acid is supplied to the etching liquid E from the phosphoric acid replenishing mechanism 4.

[0153] As explained with reference to Figure 20 and Figure 21 , the silicon concentration C of the first example reaches the second silicon concentration C2 from the first silicon concentration Cl at an earlier time point than the second example. As a result, as explained with reference to Figure 22 and Figure 23As shown, the substrate W in the first example ( Figure 22 The gap G is narrower than the substrate W in the second example. Figure 23 The gap G. Furthermore, in the second case, at a time point earlier than in the third case, the silicon concentration C increased from the first silicon concentration C1 to the second silicon concentration C2. As a result, as... Figure 23 and Figure 24 As shown, the gap G of substrate W in the second example (Fig. 23) is narrower than that of substrate W in the third example (Fig. 23). Figure 24 The gap G.

[0154] Here, for reference Figure 9 This describes the data input by the operator to the control device 110. In this embodiment, the operator inputs data representing the relationship between the etching process time t and the silicon supply flow rate R, as a set value for the silicon supply flow rate R. For example, the operator may also input data from reference... Figure 21 The data corresponding to the illustrated chart RP1 is used as the set value for the silicon supply flow rate R. In this case, the control unit 111 uses the flow rate of the silicon-containing liquid measured by the flow meter 453 of the silicon supply mechanism 45 and the set value of the silicon supply flow rate R, as follows: Figure 21 The silicon supply flow rate R is controlled as shown in Figure RP1. As a result, the silicon concentration C of the etchant E is as follows: Figure 20 As shown in Figure CP21, the shape of the substrate W changes to become Figures 18-24 The shape shown.

[0155] The above has been referenced. Figure 20 Embodiment 3 of the present invention will be described. According to this embodiment, similar to Embodiment 1, the silicon concentration C of the etching solution E can be varied during the etching of the substrate W. Therefore, according to this embodiment, the shape of the silicon oxide film Ma can be controlled, and the substrate W can be processed into a special shape.

[0156] Alternatively, the substrate processing apparatus 100 may also include a silicon concentration meter 86, similar to that in Embodiment 2. In this case, the control unit 111 controls the opening and closing of the on / off valve 452 of the silicon supply mechanism 45 based on the silicon concentration C measured by the silicon concentration meter 86. In other words, the control unit 111 controls the flow rate (silicon supply flow rate R) of the silicon-containing liquid supplied to the supplementary phosphoric acid based on the silicon concentration C measured by the silicon concentration meter 86.

[0157] More specifically, the control unit 111 controls the silicon supply flow rate R based on the silicon concentration C set value stored in the storage unit 112 and the silicon concentration C measured by the silicon concentration meter 86.

[0158] In detail, the storage section 112 stores data indicating a relationship between the processing time t of the etching processing and the silicon concentration C as a set value related to the silicon concentration C. Alternatively, the storage section 112 stores data indicating a relationship between the processing time t of the etching processing and a rate of change of the silicon concentration C. For example, the storage section 112 can also store data corresponding to the graph CP21 explained above with reference to the graph CP21. Figure 20 The graph CP21 explained above corresponds to data. In this case, the control section 111 controls the opening and closing of the opening and closing valve 452 of the silicon supply mechanism 45 in a manner that the silicon concentration C measured by the silicon concentration meter 86 follows the change of the silicon concentration C indicated by the graph CP21. Figures 1-24 The graph CP21 explained above corresponds to data. In this case, the control section 111 controls the opening and closing of the opening and closing valve 452 of the silicon supply mechanism 45 in a manner that the silicon concentration C measured by the silicon concentration meter 86 follows the change of the silicon concentration C indicated by the graph CP21.

[0159] The embodiments of the present application have been described above with reference to the accompanying drawings ( Figures 1-24 ). However, the present application is not limited to the described embodiments but can be carried out in various aspects without departing from the gist thereof. Furthermore, the plurality of constituent elements disclosed in the described embodiments can be appropriately changed. For example, a certain constituent element among all the constituent elements shown in a certain embodiment can be added to the constituent elements of another embodiment, or several constituent elements among all the constituent elements shown in a certain embodiment can be deleted from the embodiment.

[0160] The accompanying drawings are schematically showing the constituent elements in order to easily understand the application, and the thickness, length, number, interval, and the like of the illustrated constituent elements can be different from the actual ones in order to facilitate the production of the drawings. Furthermore, the constitution of the constituent elements shown in the described embodiments is an example and is not particularly limited, and various changes can be made without departing from the gist of the present application in substance.

[0161] For example, in the described embodiments, the phosphoric acid is supplied to the etching solution E in the processing tank 3 from the outside of the processing tank 3, but the phosphoric acid can also be supplied to the etching solution E inside the processing tank 3. ​

[0162] [Industrial applicability]

[0163] The present application is useful in the field of processing substrates.

[0164] [Explanation of symbols]

[0165] 3 Processing tank

[0166] 4 Phosphoric acid supply mechanism

[0167] 41 Phosphoric acid supply nozzle

[0168] 42 Phosphoric acid supply pipe

[0169] 43 Opening and closing valve, first opening and closing valve

[0170] 44 Flow meter​

[0171] 45 silicon supply mechanism

[0172] 86 silicon concentration meter

[0173] 100 substrate processing apparatus

[0174] 110 control device

[0175] 111 control unit

[0176] 112 storage unit

[0177] 113 input unit

[0178] 451 silicon supply pipe

[0179] 452 on-off valve, second on-off valve

[0180] 453 flow meter

[0181] E etching solution

[0182] G gap

[0183] M build-up structure

[0184] Ma silicon oxide film

[0185] Mb silicon nitride film

[0186] W substrate

Claims

1. A substrate processing method, comprising etching a substrate having alternating layers of silicon oxide and silicon nitride films in a processing tank using an etching solution containing phosphoric acid, and comprising: The step of immersing the substrate in the etching solution; and During the etching of the substrate, phosphoric acid is added to the etching solution in the processing tank in a manner that shows a specific change in the silicon concentration of the etching solution, thereby causing a change in the silicon concentration of the etching solution. This specific change occurs from a first concentration that slowly increases to approximately a second concentration, and then increases even more slowly near the second concentration to reach the second concentration. In the step of changing the silicon concentration of the etching solution, the replenishment flow rate of phosphoric acid is controlled based on the data in the storage unit that stores data corresponding to the specific change in the silicon concentration of the etching solution, in a manner that the silicon concentration of the etching solution measured during the etching of the substrate follows the specific change.

2. The substrate processing method according to claim 1, wherein in the step of changing the silicon concentration of the etching solution, the replenishment flow rate of phosphoric acid supplied to the etching solution is controlled based on a set value of the replenishment flow rate of phosphoric acid set according to the structure of the semiconductor device manufactured using the substrate.

3. The substrate processing method according to claim 1, wherein in the step of changing the silicon concentration of the etching solution, the phosphoric acid supplemented to the etching solution is supplied with a silicon-containing solution containing silicon.

4. The substrate processing method according to claim 3, wherein in the step of changing the silicon concentration of the etching solution, the supply flow rate of the silicon-containing solution supplied to the phosphoric acid is controlled based on a set value of the supply flow rate of the silicon-containing solution set according to the structure of the semiconductor device manufactured using the substrate.

5. The substrate processing method according to claim 3, wherein in the step of changing the silicon concentration of the etching solution, the supply flow rate of the silicon-containing solution is controlled based on the silicon concentration of the etching solution measured during etching of the substrate.

6. The substrate processing method according to claim 2 or 4, wherein the configuration of the semiconductor device represents the gap size between adjacent silicon oxide films in the stacking direction of the semiconductor device.

7. A substrate processing apparatus for etching a substrate having alternating layers of silicon oxide and silicon nitride films using an etching solution containing phosphoric acid, and comprising: A processing tank is used to store the etching solution; A substrate holding section holds the substrate within the etching solution stored in the processing tank; A phosphoric acid replenishment mechanism replenishes phosphoric acid to the etching solution in the processing tank. The control unit controls the phosphoric acid replenishment mechanism in a manner that displays a specific change in the silicon concentration of the etching solution in the processing tank during the etching of the substrate, so that the silicon concentration of the etching solution changes, the specific change being a slow increase from a first concentration to near a second concentration, and an even slower increase near the second concentration to reach the second concentration; The storage unit stores data corresponding to the specific changes in the silicon concentration of the etching solution; and A silicon concentration meter is used to measure the silicon concentration of the etching solution. The control unit controls the phosphate replenishment mechanism during the etching of the substrate, based on the data stored in the storage unit, in a manner that follows the specific change in silicon concentration measured by the silicon concentration meter during the etching of the substrate.

8. The substrate processing apparatus according to claim 7, wherein the control unit controls the phosphoric acid replenishment mechanism during etching of the substrate based on a set value of phosphoric acid replenishment flow rate set according to the construction of a semiconductor device manufactured using the substrate.

9. The substrate processing apparatus according to claim 7, further comprising a silicon supply mechanism for supplying a silicon-containing liquid to the phosphoric acid replenished to the etching solution.

10. The substrate processing apparatus according to claim 9, wherein the control unit controls the silicon supply mechanism during etching of the substrate based on a set value of the supply flow rate of the silicon-containing liquid, which is set according to the structure of the semiconductor device manufactured using the substrate.

11. The substrate processing apparatus according to claim 9, wherein the control unit controls the silicon supply mechanism during the etching of the substrate based on the silicon concentration measured by the silicon concentration meter during the etching of the substrate.

12. The substrate processing apparatus according to claim 8 or 10, wherein the configuration of the semiconductor device represents the gap size between adjacent silicon oxide films in the stacking direction of the semiconductor device.

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