Substrate processing method and substrate processing apparatus

Abstract

To provide a substrate processing method and a substrate processing apparatus for appropriately processing a substrate.SOLUTION: The present invention relates to a substrate processing method and a substrate processing apparatus 1. The substrate processing method is for processing a substrate W. The substrate W includes a first layer 31 and a second layer 32. The first layer 31 is, for example, a silicon oxide layer made of silicon oxide. The first exposed surface 31S of the first layer 31 is exposed. The first exposed surface 31S is, for example, a silicon oxide exposed surface. The second layer 32 is, for example, a silicon nitride layer made of silicon nitride. The second exposed surface 32S of the second layer 32 is exposed. The second exposed surface 32S is, for example, a silicon nitride exposed surface. The substrate processing method includes an etching step. In the etching process, an etching liquid Jn is supplied to the substrate W. The etchant Jn contains hydrofluoric acid and heavy water.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a substrate processing method and a substrate processing apparatus, for example, a semiconductor wafer, a liquid crystal display substrate, an organic electroluminescence (EL) substrate, an FPD (Flat Panel Display) substrate, an optical display substrate, a magnetic disk substrate, an optical disk substrate, a magneto-optical disk substrate, a photomask substrate, or a solar cell substrate. [Background technology]

[0002] Patent Document 1 discloses a substrate processing method for processing a substrate. The substrate includes a silicon nitride layer and a silicon oxide layer. The substrate processing method includes a film formation step and an etching step. In the film formation step, a protective film that protects the silicon nitride layer is formed on the surface of the substrate. In the etching step, the silicon nitride layer and the silicon oxide layer are etched. The processing solution includes hydrofluoric acid. The protective film inhibits etching of the silicon nitride layer by the hydrofluoric acid. This slows down the etching rate of the silicon nitride layer and selectively etches the silicon oxide layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. WO2022 / 085449 Summary of the Invention [Problem to be solved by the invention]

[0004] Even with conventional substrate processing methods, it is difficult to process substrates efficiently.

[0005] The substrate processing method disclosed in Patent Document 1 requires a film forming step before the etching step. In other words, the number of processing steps increases. This tends to increase processing time. Also, power consumption tends to increase. Therefore, even with the conventional substrate processing method, it is difficult to efficiently etch a substrate.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a substrate processing method and a substrate processing apparatus that appropriately processes a substrate. [Means for solving the problem]

[0007] The present invention provides a substrate processing method for processing a substrate, the substrate including a silicon oxide exposed surface where a silicon oxide layer made of silicon oxide is exposed, and a silicon nitride exposed surface where a silicon nitride layer made of silicon nitride is exposed, the substrate processing method including an etching step of supplying an etching solution containing hydrofluoric acid and heavy water to the substrate to selectively etch the silicon oxide exposed surface.

[0008] The substrate processing method is for processing a substrate. The substrate includes a silicon oxide layer and a silicon nitride layer. The silicon oxide layer is made of silicon oxide. In the silicon oxide layer, an exposed silicon oxide surface is exposed. The silicon nitride layer is made of silicon nitride. In the silicon nitride layer, an exposed silicon nitride surface is exposed. The substrate processing method includes an etching step. In the etching step, an etching solution is supplied to the substrate. The etching solution contains hydrofluoric acid and heavy water. This makes it possible to control the chemical reaction between the etching solution and the silicon oxide layer and the chemical reaction between the etching solution and the silicon nitride layer. In other words, it is easy to selectively etch the silicon oxide layer. Therefore, the substrate processing method efficiently processes the substrate.

[0009] In the substrate processing method, the etching solution preferably contains a pH adjuster, which makes it easy to further selectively etch the silicon oxide layer.

[0010] In the substrate processing method, the pH adjuster preferably exhibits basicity, which makes it easy to selectively etch the silicon oxide layer depending on the pH adjuster exhibiting basicity.

[0011] In the substrate processing method, the pH adjuster preferably exhibits acidity, which makes it easy to selectively etch the silicon oxide layer depending on the pH adjuster exhibiting acidity.

[0012] The substrate processing method preferably includes an adjusting step of adjusting the pH of the etching solution, and the etching solution adjusted in the adjusting step is supplied to the substrate in the etching step. Therefore, the pH of the etching solution is adjusted in the adjusting step. Therefore, it is easy to adjust the ratio of the etching rate of the silicon oxide layer to the etching rate of the silicon nitride layer.

[0013] The present invention is a substrate processing apparatus, wherein the substrate includes a silicon oxide layer made of silicon oxide and a silicon nitride layer made of silicon nitride, and the substrate processing apparatus preferably includes a supply unit that supplies an etching solution containing hydrofluoric acid and heavy water to the substrate to selectively etch the silicon oxide layer. This makes it possible to control the chemical reaction between the etching solution and the silicon oxide layer and the chemical reaction between the etching solution and the silicon nitride layer. In other words, it is easy to selectively etch the silicon oxide layer. Therefore, the substrate processing apparatus efficiently processes the substrate.

[0014] The present invention is a substrate processing apparatus that preferably includes a supply source that supplies the etching solution containing a pH adjuster to the supply unit, thereby making it easy to further selectively etch the silicon oxide layer by supplying the etching solution containing the pH adjuster.

[0015] The present invention is a substrate processing apparatus that preferably includes a generator that generates the etching solution to which a pH adjuster has been added, and the generator supplies the generated etching solution to the supply unit. Therefore, by generating the etching solution to which a pH adjuster has been added, it is easy to further selectively etch the silicon oxide layer. [Effects of the Invention]

[0016] According to the substrate processing method and substrate processing apparatus of the present invention, substrates are processed efficiently. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 2 is a plan view showing the inside of the substrate processing apparatus according to the first embodiment. [Figure 2] FIG. 2 is a control block diagram of the substrate processing apparatus according to the first embodiment. [Figure 3] Figure 3(a) is a side view of the substrate, and Figure 3(b) is a plan view of the substrate. [Figure 4] 4(a) and 4(b) are each detailed views of a portion of the substrate. [Figure 5] FIG. 2 illustrates an example of the configuration of a processing unit according to the first embodiment. [Figure 6] 3 is a flowchart showing an example of a procedure of a substrate processing method according to the first embodiment. [Figure 7] 7(a) and 7(b) are diagrams each showing a schematic diagram of a test piece. [Figure 8] 8(a) and 8(b) are diagrams each showing a schematic diagram of a test piece. [Figure 9] 1 is a table showing Example 1 and Comparative Example 1. [Figure 10] 1 is a table showing Example 2 and Comparative Example 2. [Figure 11] FIG. 10 is a diagram illustrating an example of the configuration of a processing unit according to a second embodiment. [Figure 12] FIG. 10 is a control block diagram of a substrate processing apparatus according to a second embodiment. [Figure 13]10 is a flowchart showing an example of a procedure of a substrate processing method according to a second embodiment. [Figure 14] 1 is a table showing Examples 1, 3, 5, and 7. [Figure 15] 1 is a table showing Examples 2, 4, and 6. [Figure 16] 1 is a table showing Comparative Examples 3, 5, and 7. [Figure 17] 1 is a table showing Comparative Examples 4 and 6. [Figure 18] FIG. 10 is a diagram illustrating a configuration of a processing unit according to a modified embodiment. [Figure 19] FIG. 10 is a diagram illustrating a configuration of a processing unit according to another modified embodiment.

[0018] 1. First embodiment 1-1. Overview of substrate processing equipment FIG. 1 is a plan view showing the inside of the substrate processing apparatus 1. As shown in FIG.

[0019] The substrate processing apparatus 1 performs processing on the substrate W. The processing in the substrate processing apparatus 1 includes an etching process. The etching process in the substrate processing apparatus 1 is a process in which the substrate W is etched with an etching liquid. That is, the etching process in the substrate processing apparatus 1 is a wet etching process.

[0020] The term "etching process" in this specification includes, for example, a removal process and a dissolution process. A removal process is a process of removing an object on the substrate W. A removal process includes, for example, a lift-off process. A dissolution process is a process of dissolving an object on the substrate W. An object on the substrate W is, for example, a part of the substrate W. An object on the substrate W is, for example, a layer on the substrate W or a film on the substrate W. An object on the substrate W is, for example, a foreign object for the substrate W. An object on the substrate W is, for example, a particle attached to the substrate W or a residue attached to the substrate W.

[0021] Even if the removal process is for cleaning the substrate W, the removal process is an example of the "etching process" in this specification. Even if the dissolution process is for cleaning the substrate W, the dissolution process is an example of the "etching process" in this specification.

[0022] The substrate processing apparatus 1 includes an indexer unit 3 and a processing block 7. The processing block 7 is connected to the indexer unit 3. The indexer unit 3 supplies substrates W to the processing block 7. The processing block 7 processes the substrates W. The indexer unit 3 retrieves the substrates W from the processing block 7.

[0023] For convenience, in this specification, the direction in which the indexer unit 3 and the processing block 7 are aligned is referred to as the "front-rear direction X." The front-rear direction X is horizontal. Within the front-rear direction X, the direction from the processing block 7 toward the indexer unit 3 is referred to as the "front." The direction opposite to the front is referred to as the "rear." The direction perpendicular to the front-rear direction X is referred to as the "width direction Y." The width direction Y is horizontal. One direction in the "width direction Y" is referred to as the "right" as appropriate. The direction opposite to the right is referred to as the "left." When the front-rear direction X and the width direction Y are not distinguished, they are referred to as the "horizontal direction." The direction perpendicular to the horizontal direction is referred to as the "vertical direction Z." In each figure, for reference, front, back, right, left, top, and bottom are indicated as appropriate.

[0024] The carrier C is used to transport substrates W outside the substrate processing apparatus 1. For example, the carrier C is transported between the substrate processing apparatus 1 and an external device of the substrate processing apparatus 1. The carrier C accommodates multiple substrates W. The carrier C is, for example, a FOUP (Front Opening Unified Pod), a SMIF (Standard Mechanical Interface), or an OC (Open Cassette).

[0025] The indexer unit 3 includes a plurality of (for example, four) carrier placement units 4. The carriers C are placed on the carrier placement units 4.

[0026] The indexer unit 3 includes a transport mechanism 5. The transport mechanism 5 transports the substrate W. The transport mechanism 5 transports the substrate W between the carriers C on the carrier platform 4 and the processing block .

[0027] The transport mechanism 5 includes a hand 5a and a hand driver 5b. The hand 5a supports the substrate W. The hand driver 5b is connected to the hand 5a. The hand driver 5b moves the hand 5a. The hand driver 5b moves the hand 5a, for example, in the front-rear direction X, the width direction Y, and the vertical direction Z. The hand driver 5b rotates the hand 5a, for example, in a horizontal plane.

[0028] The processing block 7 includes a plurality of processing units 11. Each processing unit 11 performs processing on a substrate W.

[0029] Each processing unit 11 includes a substrate holder 12. The substrate holder 12 holds a substrate W.

[0030] The processing block 7 includes a transport mechanism 8. The transport mechanism 8 transports the substrate W. The transport mechanism 8 transports the substrate W between the indexer unit 3 and the processing unit 11. The transport mechanism 8 transports the substrate W between the transport mechanism 5 and the substrate holder 12.

[0031] The transport mechanism 8 includes a hand 8a and a hand driver 8b. The hand 8a supports the substrate W. The hand driver 8b is connected to the hand 8a. The hand driver 8b moves the hand 8a. The hand driver 8b moves the hand 8a, for example, in the front-rear direction X, the width direction Y, and the vertical direction Z. The hand driver 8b rotates the hand 8a, for example, in a horizontal plane.

[0032] 2 is a control block diagram of the substrate processing apparatus 1. The substrate processing apparatus 1 includes a control unit 10. The control unit 10 controls the transfer mechanisms 5 and 8 and the processing unit 11. The control unit 10 is connected to the transfer mechanisms 5 and 8 and the processing unit 11 so as to be able to communicate with each other.

[0033] The control unit 10 is realized by, for example, a central processing unit (CPU), a random access memory (RAM), and a storage medium. The central processing unit executes arithmetic processing. The random access memory functions as a work area for the arithmetic processing. The storage medium is, for example, a fixed disk. The control unit 10 has various types of information pre-stored in the storage medium. The information held by the control unit 10 includes, for example, transport information and processing information. The transport information defines the operation procedures of the transport mechanisms 5 and 8. The processing information defines the operation procedures of the processing unit 11. The processing information is also called a processing recipe.

[0034] An example of the operation of the substrate processing apparatus 1 will now be briefly described.

[0035] The transport mechanism 5 carries out the substrate W from the carrier C on the carrier platform 4. The transport mechanism 5 hands over the substrate W to the transport mechanism 8.

[0036] The transport mechanism 8 delivers the substrate W to the processing unit 11. Specifically, the transport mechanism 8 places the substrate W on the substrate holder 12. The substrate holder 12 holds the substrate W.

[0037] Each processing unit 11 processes the substrate W held by the substrate holder 12. Each processing unit 11 performs an etching process on the substrate W.

[0038] After the processing unit 11 has processed the substrate W, the transport mechanism 8 takes the substrate W from the processing unit 11. Specifically, the transport mechanism 8 takes the substrate W from the substrate holder 12. The transport mechanism 8 hands the substrate W over to the transport mechanism 5.

[0039] The transport mechanism 5 loads the substrate W into the carrier C.

[0040] 1-2. Substrate W 3(a) is a side view of the substrate W. FIG. 3(b) is a plan view of the substrate W.

[0041] The substrate W is, for example, any one of a semiconductor wafer, a substrate for a liquid crystal display, a substrate for an organic EL (electroluminescence), a substrate for an FPD (flat panel display), a substrate for an optical display, a substrate for a magnetic disk, a substrate for an optical disk, a substrate for a magneto-optical disk, a substrate for a photomask, and a substrate for a solar cell.

[0042] The substrate W has a thin, flat plate shape and is substantially circular in plan view.

[0043] The substrate W has a surface W1, a surface W2, and a peripheral edge W3. The surface W2 is opposite the surface W1. The surfaces W1 and W2 each have a substantially circular shape in a plan view. The surfaces W1 and W2 each are substantially planar. The surfaces W1 and W2 each are substantially flat.

[0044] 4(a) and 4(b) are each a detailed view of a portion of the substrate W. The substrate W includes a first layer 31 and a second layer 32. The first layer 31 and the second layer 32 are each a part of the substrate W. The first layer 31 and the second layer 32 are each a structure. The first layer 31 and the second layer 32 are each tiny.

[0045] The first layer 31 and the second layer 32 are each located on the surface W1.

[0046] The first layer 31 has a first exposed surface 31S. The first exposed surface 31S is exposed.

[0047] The second layer 32 has a second exposed surface 32S. The second exposed surface 32S is exposed.

[0048] The first exposed surface 31S has a first exposed width D31, and the second exposed surface 32S has a second exposed width D32.

[0049] The second exposed width D32 may be smaller than the first exposed width D31. The second exposed width D32 may be larger than the first exposed width D31. The second exposed width D32 may be the same as the first exposed width D31.

[0050] The first exposed surface 31S has a first exposed area E31, and the second exposed surface 32S has a second exposed area E32.

[0051] The second exposed area E32 may be smaller than the first exposed area E31. The second exposed area E32 may be larger than the first exposed area E31. The second exposed area E32 may be the same as the first exposed area E31.

[0052] For example, the first layer 31 has a plate shape. For example, the first layer 31 has a film shape. The first exposed surface 31S corresponds to the upper surface of the first layer 31, for example.

[0053] For example, the second layer 32 has a plate shape. For example, the second layer 32 has a film shape. The second exposed surface 32S corresponds to the surface of the second layer 32, for example.

[0054] Figure 4(a) shows the substrate W before it is etched, and Figure 4(b) shows the substrate W after it has been etched.

[0055] The first layer 31 is etched. The first exposed surface 31S is etched. The first layer 31 is an example of a layer to be etched.

[0056] The first layer 31 is etched in a direction F31. The direction F31 is, for example, perpendicular to the first exposed surface 31S. As the first layer 31 is etched, the length of the first layer 31 in the direction F31 decreases.

[0057] 4(b) shows the etching amount H31 of the first layer 31. The etching amount H31 is, for example, the amount of reduction in the length of the first layer 31 in the direction F31.

[0058] The etching rate of the first layer 31 can be obtained by, for example, dividing the etching amount H31 by the etching time of the first layer 31.

[0059] The second layer 32 is also etched. The second exposed surface 32S is etched. The second layer 32 is also an example of a layer to be etched.

[0060] The second layer 32 is etched in a direction F32. The direction F32 is, for example, perpendicular to the second exposed surface 32S. By etching the second layer 32, the length of the second layer 32 in the direction F32 decreases.

[0061] 4(b) shows the etching amount H32 of the second layer 32. The etching amount H32 is, for example, the amount of reduction in the length of the second layer 32 in the direction F32.

[0062] The etching rate of the second layer 32 can be obtained by, for example, dividing the etching amount H32 by the etching time of the second layer 32.

[0063] The first layer 31 is selectively etched. The second layer 32 is selectively etched. Selective etching means selectively removing a specific film on the surface W1 where multiple films with different compositions are stacked. The first layer 31 is more easily selectively etched than the second layer 32.

[0064] The first layer 31 is made of, for example, silicon oxide.

[0065] The second layer 32 is made of, for example, silicon nitride.

[0066] The first layer 31 may be, for example, a thermal oxide film. The first layer 31 may be formed by chemical vapor deposition (CVD). The second layer 32 may be formed by CVD.

[0067] 1-3. Configuration of processing unit 11 FIG. 5 is a diagram showing the configuration of the processing unit 11 of the first embodiment.

[0068] Each processing unit 11 has the same structure. The processing units 11 are classified as single-wafer processing units, i.e., each processing unit 11 processes only one substrate W at a time.

[0069] The substrate holder 12 holds only one substrate W at a time. The substrate holder 12 holds the substrate W in a substantially horizontal position. When the substrate W is held by the substrate holder 12, the surface W1 is horizontal.

[0070] When the substrate W is held by the substrate holder 12, the surface W1 faces upward. When the substrate W is held by the substrate holder 12, the surface W1 corresponds to the upper surface of the substrate W. When the substrate W is held by the substrate holder 12, the surface W2 corresponds to the lower surface of the substrate W. The lower surface of the substrate W is also called the backside of the substrate W.

[0071] The substrate holder 12 contacts at least one of the surface W2 and the peripheral edge W3, and does not contact the surface W1.

[0072] The substrate holder 12 is located below the substrate W that it holds.

[0073] The processing unit 11 includes a rotational drive unit 14. The rotational drive unit 14 is connected to the substrate holding unit 12. The rotational drive unit 14 rotates the substrate holding unit 12. The substrate W held by the substrate holding unit 12 rotates integrally with the substrate holding unit 12. The substrate W held by the substrate holding unit 12 rotates, for example, around a rotational axis B. The rotational axis B passes through the center of the substrate W, for example. The rotational axis B extends, for example, in the vertical direction Z.

[0074] The processing unit 11 includes a supply unit 15n. The supply unit 15n supplies an etching liquid Jn to the substrate W to etch the first layer 31 and the second layer 32.

[0075] Specifically, the supply unit 15n supplies the etching liquid Jn to the substrate W held by the substrate holding unit 12. The supply unit 15n supplies the etching liquid Jn to the surface W1 of the substrate W held by the substrate holding unit 12.

[0076] The supply unit 15n includes a nozzle 16n. The nozzle 16n is disposed above the substrate W held by the substrate holder 12. The nozzle 16n ejects an etching liquid Jn.

[0077] The etching solution Jn contains hydrofluoric acid and heavy water.

[0078] The etching solution Jn can be obtained, for example, by diluting hydrofluoric acid with heavy water.

[0079] The volume of heavy water contained in the etching solution Jn is larger than the volume of hydrofluoric acid contained in the etching solution Jn. For example, the volume of heavy water contained in the etching solution Jn is more than 10 times the volume of hydrofluoric acid contained in the etching solution Jn. For example, the volume of heavy water contained in the etching solution Jn is more than 20 times the volume of hydrofluoric acid contained in the etching solution Jn.

[0080] The etching solution Jn is substantially free of deionized water. For example, the volume of deionized water contained in the etching solution Jn is smaller than the volume of heavy water contained in the etching solution Jn. For example, the volume of deionized water contained in the etching solution Jn is smaller than 10% of the volume of heavy water contained in the etching solution Jn. For example, the volume of deionized water contained in the etching solution Jn is smaller than 5% of the volume of heavy water contained in the etching solution Jn.

[0081] The etching solution Jn is substantially free of a pH adjuster.

[0082] Here, the pH adjuster may, for example, be acidic. The pH adjuster may, for example, contain an acid. The acid of the pH adjuster may, for example, be an acid other than hydrofluoric acid. The pH adjuster may, for example, be basic. The pH adjuster may, for example, contain a base.

[0083] For example, the pH of etching solution Jn is adjusted only with hydrofluoric acid and heavy water. The pH of etching solution Jn is not adjusted with any compounds other than hydrofluoric acid and heavy water. pH is also called hydrogen ion concentration.

[0084] The etchant Jn selectively etches the first layer 31. The etchant Jn selectively etches the second layer 32. The etchant Jn selectively etches the first layer 31 more than the second layer 32.

[0085] The substrate processing apparatus 1 includes a supply source 17n. The supply source 17n is in communication with the supply unit 15n. The supply source 17n stores an etching liquid Jn. The supply source 17n supplies the etching liquid Jn to the supply unit 15n.

[0086] The substrate processing apparatus 1 includes a pipe 18n and a valve 19n. The pipe 18n has a first end connected to a supply unit 15n. The pipe 18n has a second end connected to a supply source 17n. The valve 19n is provided on the pipe 18n. The valve 19n controls the supply of the etching liquid Jn by the supply unit 15n. Specifically, when the valve 19n is open, the supply source 17n supplies the etching liquid Jn to the supply unit 15n, and the supply unit 15n supplies the etching liquid Jn to the substrate W. When the valve 19n is closed, the supply source 17n does not supply the etching liquid Jn to the supply unit 15n, and the supply unit 15n does not supply the etching liquid Jn to the substrate W.

[0087] The processing unit 11 includes a supply part 20. The supply part 20 supplies a rinse liquid L to the substrate W.

[0088] Specifically, the supply unit 20 supplies the rinse liquid L to the substrate W held by the substrate holder 12. The supply unit 20 supplies the rinse liquid L to the surface W1 of the substrate W held by the substrate holder 12.

[0089] For example, the supply unit 20 includes a nozzle 21. The nozzle 21 is disposed above the substrate W held by the substrate holder 12. The nozzle 21 ejects the rinse liquid L.

[0090] The rinse liquid L is, for example, at least one of deionized water and isopropyl alcohol. The rinse liquid L is also called a cleaning liquid.

[0091] The supply unit 20 communicates with a supply source 22. The supply source 22 stores the rinse liquid L. The supply source 22 sends the rinse liquid L to the supply unit 20.

[0092] The substrate processing apparatus includes a pipe 23 and a valve 24. The pipe 23 has a first end connected to a supply unit 20. The pipe 23 has a second end connected to a supply source 22. The valve 24 is provided on the pipe 23. The valve 24 controls the supply of the rinse liquid L by the supply unit 20.

[0093] The processing unit 11 includes a supply unit 25. The supply unit 25 supplies a drying gas to the substrate W.

[0094] Specifically, the supply unit 25 supplies a dry gas to the substrate W held by the substrate holder 12. The supply unit 25 supplies the dry gas to the surface W1 of the substrate W held by the substrate holder 12.

[0095] The supply unit 25 includes a nozzle 26. The nozzle 26 is disposed above the substrate W held by the substrate holder 12. The nozzle 26 ejects a drying gas.

[0096] The dry gas includes at least one of air and an inert gas, for example, compressed air, and nitrogen gas.

[0097] The supply unit 25 is connected to a supply source 27. The supply source 27 stores a dry gas. The supply source 27 delivers the dry gas to the supply unit 25.

[0098] The substrate processing apparatus 1 includes a pipe 28 and a valve 29. The pipe 28 has a first end connected to a supply unit 25. The pipe 28 has a second end connected to a supply source 27. The valve 29 is provided on the pipe 28. The valve 29 controls the supply of the drying gas by the supply unit 25.

[0099] The processing unit 11 may further include a cup (not shown). The cup is disposed to the side of the substrate holding part 12. The cup surrounds the substrate holding part 12. The cup catches liquid splashed from the substrate W held by the substrate holding part 12.

[0100] 2, the control unit 10 controls the rotary drive unit 14. The control unit 10 controls the valves 19n, 24, and 29.

[0101] The supply unit 15n is an example of the supply unit defined in the present invention.

[0102] 1-4. Substrate processing method procedure Please refer to Figures 4(a), 4(b), 5 and 6. Figure 6 is a flowchart showing the procedure of the substrate processing method of the first embodiment.

[0103] The substrate processing method is performed in the substrate processing apparatus 1. The substrate processing method is mainly performed in the processing unit 11. The substrate processing method is for processing a substrate W. The substrate processing method is for processing a substrate W held by the substrate holder 12.

[0104] The substrate processing method includes an etching step, a rinsing step, and a drying step. The rinsing step is performed after the etching step. The drying step is performed after the rinsing step.

[0105] Each step of the substrate processing method will be described below. In the following description, each element of the processing unit 11 operates under the control of the control unit 10.

[0106] Step S1: Etching process In the etching step, an etching liquid Jn is supplied to the substrate W. Specifically, the supply unit 15n supplies the etching liquid Jn to the substrate W held by the substrate holder 12. As described above, the etching liquid Jn contains hydrofluoric acid and heavy water.

[0107] In the etching process, the first exposed surface 31S is exposed to the etchant Jn, and the second exposed surface 32S is exposed to the etchant Jn.

[0108] In the etching process, the first exposed surface 31S comes into contact with the etchant Jn, and the second exposed surface 32S comes into contact with the etchant Jn.

[0109] In the etching process, the first layer 31 and the second layer 32 are etched. In the etching process, the first layer 31 and the second layer 32 are etched simultaneously.

[0110] The first layer 31 is selectively etched by the etching solution Jn. The second layer 32 is selectively etched by the etching solution Jn. The first layer 31 is selectively etched by the etching solution Jn more than the second layer 32. Furthermore, as will be described later, the SiO2 / SiN ratio is improved by the etching solution Jn.

[0111] Step S2: Rinse process In the rinsing step, a rinsing liquid L is supplied to the substrate W. Specifically, the supply unit 20 supplies the rinsing liquid L to the substrate W held by the substrate holder 12. In the rinsing step, the rinsing liquid L removes the etching liquid Jn from the substrate W. Etching of the first layer 31 and the second layer 32 is stopped.

[0112] Step S3: Drying process In the drying step, the substrate W is dried. For example, the rotation drive unit 14 rotates the substrate W held by the substrate holder 12. For example, the supply unit 25 supplies a drying gas to the substrate W held by the substrate holder 12.

[0113] In the etching step, the rotation drive unit 14 may rotate the substrate W held by the substrate holder 12. In the rinsing step, the rotation drive unit 14 may rotate the substrate W held by the substrate holder 12.

[0114] 1-5.Advantages of Etchant Jn The advantages of the etching solution Jn will be explained using Example 1 and Comparative Example 1.

[0115] 7(a) and 7(b) are diagrams each showing a schematic diagram of a test piece. 8(a) and 8(b) are diagrams each showing a schematic diagram of a test piece. Before Examples 1 and 2 and Comparative Examples 1 and 2 are performed, test pieces 40 and 50 are prepared.

[0116] The test pieces 40 and 50 each resemble the substrate W.

[0117] Please refer to Figures 7(a) and 7(b).

[0118] Layer 41 of test strip 40 mimics first layer 31 .

[0119] The layer 41 is the layer to be etched and is made of silicon oxide.

[0120] The layer 41 has an exposed surface 41S. The exposed surface 41S is exposed. The exposed surface 41S has an exposed width D41. The exposed width D41 is, for example, 20 mm. The exposed surface 41S has an exposed length I41. The exposed length I41 is, for example, 20 mm.

[0121] 7(a) shows the test piece 40 before etching, and FIG. 7(b) shows the test piece 40 after etching. FIG. 7(b) shows the etching amount H41 of the layer 41.

[0122] Layer 41 is etched. Exposed surface 41S is etched.

[0123] The layer 41 is etched in a direction F41, which is perpendicular to the exposed surface 41S. As the layer 41 is etched, the length of the layer 41 in the direction F41 decreases.

[0124] The etching amount H41 is the amount of reduction in the length of the layer 41 in the direction F41.

[0125] The test piece 40 further includes a layer 43. The layer 43 is not a layer to be etched and is composed of single crystal silicon.

[0126] Layer 41 is formed on layer 43. Layer 41 is in contact with layer 43.

[0127] Please refer to Figures 8(a) and 8(b).

[0128] Layer 51 of test strip 50 mimics second layer 32 .

[0129] The layer 51 is the layer to be etched and is made of silicon nitride.

[0130] Layer 51 has an exposed surface 51S.

[0131] The exposed surface 51S has an exposed width D51 and an exposed length I51.

[0132] The exposed width D51 is, for example, 20 mm. The exposed surface 51S has an exposed length I51. The exposed length I51 is, for example, 20 mm.

[0133] 8(a) shows the test piece 50 before etching, and FIG. 8(b) shows the test piece 50 after etching. FIG. 8(b) shows the etching amount H51 of the layer 51.

[0134] Layer 51 is etched. Exposed surface 51S is etched.

[0135] The layer 51 is etched in a direction F51, which is perpendicular to the exposed surface 51S. As the layer 51 is etched, the length of the layer 51 in the direction F51 decreases.

[0136] The etching amount H51 is the amount of reduction in the length of the layer 51 in the direction F51.

[0137] Test strip 50 further comprises layer 53. Layer 53 is identical to layer 43.

[0138] 9 is a table showing Example 1 and Comparative Example 1. FIG. 10 is a table showing Example 2 and Comparative Example 2.

[0139] Examples 1 and 2 and Comparative Examples 1 and 2 will be described. The etching solutions used in Examples 1 and 2 and Comparative Examples 1 and 2 are different. Therefore, the etching solution used in Example 1 will be referred to as "etching solution Jn1." The etching solution used in Comparative Example 1 will be referred to as "etching solution Kn1." The etching solution used in Example 2 will be referred to as "etching solution Jn2." The etching solution used in Comparative Example 2 will be referred to as "etching solution Kn2."

[0140] The conditions for Example 1 will be explained. A series of treatments is performed on a test piece. The series of treatments consists of an etching step, a rinsing step, and a drying step. Similarly, the series of treatments is performed on a test piece.

[0141] In the etching process, the etching solution Jn1 is supplied to the test piece 4050. In the etching process, the layer 4151 is etched. In the etching process, the exposed surfaces 41S and 5S are etched. The etching solution Jn1 contains hydrofluoric acid and heavy water. The hydrofluoric acid has a concentration of 50 wt%. The volume ratio of hydrofluoric acid to heavy water in the etching solution Jn1 is as follows: Hydrofluoric acid: heavy water = 1:29 (volume ratio)

[0142] In the rinsing step, a rinsing liquid L is supplied to the test pieces 40 and 50. The rinsing liquid L is deionized water.

[0143] In the drying step, a drying gas is supplied to the test pieces 40, 50. The drying gas is nitrogen gas.

[0144] The conditions of Comparative Example 1 will be described. In the etching process, an etching solution Kn1 is supplied to the test pieces 40 and 50. The etching solution Kn1 contains hydrofluoric acid and deionized water. The volume ratio of hydrofluoric acid to deionized water in the etching solution Kn1 is as follows: Hydrofluoric acid: deionized water = 1:29 (volume ratio) Other conditions in Comparative Example 1 are the same as those in Example 1.

[0145] The conditions of Example 2 will be described. In the etching process, an etching solution Jn2 is supplied to the test pieces 40 and 50. The etching solution Jn2 contains hydrofluoric acid and heavy water. The volume ratio of hydrofluoric acid to heavy water in the etching solution Jn2 is as follows: Hydrofluoric acid: heavy water = 5:500 (volume ratio) Other conditions in Example 2 are the same as those in Example 1.

[0146] The conditions of Comparative Example 2 will be described. In the etching process, the etching solution Kn2 is supplied to the test pieces 40 and 50. The etching solution Kn2 contains hydrofluoric acid and deionized water. The volume ratio of hydrofluoric acid to deionized water in the etching solution Kn2 is as follows: Hydrofluoric acid: deionized water = 5:500 (volume ratio) Other conditions in Comparative Example 2 are the same as those in Example 1.

[0147] After the test specimen 40 was treated as in Example 1, the test specimen 40 was evaluated by its etching rate.

[0148] The etching amounts H41 and H51 were obtained 5, 10, 15, 20, 25, and 30 minutes after the start of the etching process. These times correspond to the "times at which the etching amounts were obtained" described below.

[0149] 9, the etching amounts H41 and H51, the average etching rates avL41 and avM51, and the SiO2 / SiN ratio N in Example 1 and Comparative Example 1 are shown.

[0150] FIG. 9 shows the etching amounts H41 and H51, the average etching rates avL41 and avM51, and the SiO2 / SiN ratio N in Example 1 and Comparative Example 1.

[0151] The average etching rates avL41 and avM51 are the average values ​​of the etching rates calculated from the etching amounts H41 and H51 obtained after 5, 10, 15, 20, 25, and 30 minutes. The units of the average etching rates avL41 and avM51 are nm / min.

[0152] The SiO2 / SiN ratio N is the ratio of the SiO2 etching rate to the SiN etching rate. For example, the SiO2 / SiN ratio N is the ratio of the average etching rate avL41 to the average etching rate avM51. In other words, the SiO2 / SiN ratio N indicates how much SiO2 can be etched when etching 1 nm of SiN. Specifically, the ratio N is defined by the following formula: N=avL41 / avM51

[0153] The SiO2 / SiN ratio N is also called the SiO2 / SiN selectivity ratio.

[0154] In Example 1, the etching amount H41 was 42.60 nm, 84.42 nm, 127.07 nm, 169.90 nm, 212.36 nm, and 253.88 at each time the etching amount was obtained. The average etching rate avL41 was 8.48 nm / min.

[0155] In Example 1, the etching amount H51 was 3.89 nm, 7.66 nm, 11.46 nm, 15.11 nm, 19.15 nm, and 22.86 at each time the etching amount was obtained. The average etching rate avL51 was 0.76 nm / min.

[0156] In Example 1, the SiO2 / SiN ratio N was 11.12.

[0157] In Comparative Example 1, the etching amount H41 was 55.08 nm, 111.00 nm, 161.82 nm, 215.52 nm, 272.06 nm, and 328.70 nm at each time the etching amount was obtained. The average etching rate avL41 was 10.89 nm / min.

[0158] In Comparative Example 1, the etching amount H51 was 5.36 nm, 10.45 nm, 15.86 nm, 21.01 nm, 26.13 nm, and 31.37 nm at each time the etching amount was obtained. The average etching rate avL51 was 1.05 nm / min.

[0159] In Comparative Example 1, the SiO2 / SiN ratio N was 10.39.

[0160] From Example 1 and Comparative Example 1, the following can be said.

[0161] With reference to Example 1 and Comparative Example 1, the average etching rate avL41 of layer 41 by the etching solution Jn1 is lower than the average etching rate avL41 of layer 41 by the etching solution Kn1. The average etching rate avM51 of layer 51 by the etching solution Jn1 is even lower than the average etching rate avM51 of layer 51 by the etching solution Kn1. Therefore, the SiO2 / SiN ratio N by the etching solution Jn1 is higher than the SiO2 / SiN ratio N by the etching solution Kn1. As a result, by replacing the deionized water in the etching solution Kn1 with heavy water, the etching solution Jn1 can improve the SiO2 / SiN ratio N.

[0162] Referring to FIG. 10, the etching rates L41 and M51, the average etching rates avL41 and avM51, and the SiO2 / SiN ratio N in Example 2 and Comparative Example 2 are shown.

[0163] In Example 2, the etching amount H41 was 12.70 nm, 24.46 nm, 37.02 nm, 48.64 nm, 62.38 nm, and 74.12 nm at each time the etching amount was obtained. The average etching rate avL41 was 2.47 nm / min.

[0164] In Example 2, the etching amount H51 was 1.64 nm, 3.08 nm, 4.52 nm, 6.02 nm, 7.45 nm, and 8.97 nm at each time the etching amount was obtained. The average etching rate avL51 was 0.30 nm / min.

[0165] In Example 2, the SiO2 / SiN ratio N was 8.23.

[0166] In Comparative Example 2, the etching amount H41 was 15.14 nm, 31.60 nm, 46.54 nm, 62.60 nm, 77.92 nm, and 94.76 nm at each time the etching amount was obtained. The average etching rate avL41 was 3.13 nm / min.

[0167] In Comparative Example 2, the etching amount H51 was 2.30 nm, 4.56 nm, 6.81 nm, 8.79 nm, 11.09 nm, and 13.25 nm at each time the etching amount was obtained. The average etching rate avL51 was 0.44 nm / min.

[0168] In Comparative Example 2, the SiO2 / SiN ratio N was 7.06.

[0169] From Example 2 and Comparative Example 2, the following can be said.

[0170] With reference to Example 2 and Comparative Example 2, the average etching rate avL41 of layer 41 by etching solution Jn2 is lower than the average etching rate avL41 of layer 41 by etching solution Kn2. The average etching rate avM51 of layer 51 by etching solution Jn2 is even lower than the average etching rate avM51 of layer 51 by etching solution Kn2. Therefore, the SiO2 / SiN ratio N by etching solution Jn2 is higher than the SiO2 / SiN ratio N by etching solution Kn2. As a result, by replacing deionized water in the etching solution Kn2 with heavy water, the etching solution Jn2 can improve the SiO2 / SiN ratio N.

[0171] 1-6. Effects of the first embodiment

[0172] The substrate processing method is for processing a substrate W. The substrate W includes a first layer 31 and a second layer 32. The first layer 31 is, for example, a silicon oxide layer made of silicon oxide. A first exposed surface 31S is exposed in the first layer 31. The first exposed surface 31S is, for example, an exposed silicon oxide surface. The second layer 32 is, for example, a silicon nitride layer made of silicon nitride. A second exposed surface 32S is exposed in the second layer 32. The second exposed surface 32S is, for example, an exposed silicon nitride surface.

[0173] The substrate processing method includes an etching step. In the etching step, an etchant Jn is supplied to the substrate W. The etchant Jn contains hydrofluoric acid and heavy water. This makes it possible to control the chemical reaction between the etchant Jn and the first layer 31 and the chemical reaction between the etchant Jn and the second layer 32. In other words, it is easy to selectively etch the first layer 31. Therefore, the substrate W is appropriately processed according to the substrate processing method.

[0174] The substrate W includes a first layer 31 and a second layer 32. The substrate processing apparatus 1 includes a supply unit 15. The supply unit 15 supplies an etching liquid Jn to the substrate W to selectively etch the first layer 31. This makes it possible to control the chemical reaction between the etching liquid Jn and the first layer 31 and the chemical reaction between the etching liquid Jn and the second layer 32. In other words, it is easy to selectively etch the first layer 31. Therefore, the substrate processing apparatus 1 appropriately processes the substrate W.

[0175] 2. Second embodiment A substrate processing apparatus 1 and a substrate processing method according to a second embodiment will be described with reference to the drawings. Note that the same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The second embodiment is substantially the same as the first embodiment in terms of the outline of the substrate processing apparatus 1 and the structure of the substrate W. The processing unit 11 according to the second embodiment is different from the processing unit 11 according to the first embodiment.

[0176] 2-1. Configuration of processing unit 11 11 is a diagram showing the configuration of a processing unit 11 according to the second embodiment. The processing unit 11 includes a supply unit 15a in addition to supply units 15n, 20, and 25. The supply unit 15a supplies an etching solution Ja to the substrate W to etch the first layer 31 and the second layer 32.

[0177] Specifically, the supply unit 15a supplies the etching liquid Ja to the substrate W held by the substrate holding unit 12. The supply unit 15a supplies the etching liquid Ja to the surface W1 of the substrate W held by the substrate holding unit 12.

[0178] The supply unit 15a includes a nozzle 16a. The nozzle 16a is disposed above the substrate W held by the substrate holder 12. The nozzle 16a ejects the etching liquid Ja.

[0179] Etching solution Ja contains hydrofluoric acid and heavy water, and further contains a first pH adjuster.

[0180] The etching solution Ja is obtained by, for example, adding a first pH adjuster to a solution in which hydrofluoric acid is diluted with heavy water.

[0181] The volume of heavy water contained in etching solution Ja is larger than the volume of hydrofluoric acid contained in etching solution Ja. For example, the volume of heavy water contained in etching solution Ja is more than 10 times the volume of hydrofluoric acid contained in etching solution Ja. For example, the volume of heavy water contained in etching solution Ja is more than 20 times the volume of hydrofluoric acid contained in etching solution Ja.

[0182] The etching solution Ja does not substantially contain deionized water. For example, the volume of deionized water contained in the etching solution Ja is smaller than the volume of heavy water contained in the etching solution Ja. For example, the volume of deionized water contained in the etching solution Ja is smaller than 10% of the volume of heavy water contained in the etching solution Ja. For example, the volume of deionized water contained in the etching solution Ja is smaller than 5% of the volume of heavy water contained in the etching solution Ja.

[0183] The pH of the etching solution Ja is adjusted by the first pH adjuster.

[0184] The first pH adjuster lowers the pH of the etching solution Ja.

[0185] As described above, the etching solution Jn does not contain a pH adjuster. Therefore, the pH of the etching solution Ja is different from that of the etching solution Jn. For example, the pH of the etching solution Ja is lower than that of the etching solution Jn.

[0186] The first pH adjuster exhibits acidity. In other words, the first pH adjuster is an acid. The first pH adjuster is, for example, an acid other than hydrofluoric acid. For example, the first pH adjuster is hydrochloric acid.

[0187] The processing unit 11 includes a supply unit 15b. The supply unit 15b supplies an etching liquid Jb to the substrate W to etch the first layer 31 and the second layer 32.

[0188] Specifically, the supply unit 15b supplies the etching liquid Jb to the substrate W held by the substrate holding unit 12. The supply unit 15b supplies the etching liquid Jb to the surface W1 of the substrate W held by the substrate holding unit 12.

[0189] The supply unit 15b includes a nozzle 16b. The nozzle 16b is disposed above the substrate W held by the substrate holder 12. The nozzle 16b ejects the etching liquid Jb.

[0190] The etching solution Jb contains hydrofluoric acid and heavy water, and further contains a second pH adjuster.

[0191] The etching solution Jb can be obtained by, for example, adding a second pH adjuster to a solution obtained by diluting hydrofluoric acid with heavy water.

[0192] The volume of heavy water contained in the etching solution Jb is larger than the volume of hydrofluoric acid contained in the etching solution Jb. For example, the volume of heavy water contained in the etching solution Jb is more than 10 times the volume of hydrofluoric acid contained in the etching solution Jb. For example, the volume of heavy water contained in the etching solution Jb is more than 20 times the volume of hydrofluoric acid contained in the etching solution Jb.

[0193] The etching solution Jb is substantially free of deionized water. For example, the volume of deionized water contained in the etching solution Jb is smaller than the volume of heavy water contained in the etching solution Jb. For example, the volume of deionized water contained in the etching solution Jb is smaller than 10% of the volume of heavy water contained in the etching solution Jb. For example, the volume of deionized water contained in the etching solution Jb is smaller than 5% of the volume of heavy water contained in the etching solution Jb.

[0194] The pH of the etching solution Jb is adjusted by a second pH adjuster.

[0195] The second pH adjuster increases the pH of the etching solution Ja.

[0196] The pH of the etching solution Jb is different from the pH of the etching solution Jn, for example, the pH of the etching solution Jb is higher than the pH of the etching solution Jn.

[0197] The pH of the etching solution Jb is different from the pH of the etching solution Ja. For example, the pH of the etching solution Jb is higher than the pH of the etching solution Ja.

[0198] The composition of the second pH adjuster is different from the composition of the first pH adjuster.

[0199] The second pH adjuster exhibits basicity. In other words, the second pH adjuster is a base. The second pH adjuster is, for example, a weak base. The second pH adjuster is, for example, ammonia water. The second pH adjuster includes, for example, at least one of ammonia water, ammonium hydroxide, tetramethylammonium hydroxide, potassium hydroxide, and sodium hydroxide.

[0200] The substrate processing apparatus 1 includes a supply source 17a. The supply source 17a is in communication with the supply unit 15a. The supply source 17a stores an etching liquid Ja. The supply source 17a supplies the etching liquid Ja to the supply unit 15a.

[0201] The substrate processing apparatus includes a pipe 18a and a valve 19a. The pipe 18a has a first end connected to a supply unit 15a. The pipe 18a has a second end connected to a supply source 17a. The valve 19a is provided on the pipe 18a. The valve 19a controls the supply of the etching solution Ja by the supply unit 15a.

[0202] The substrate processing apparatus 1 includes a supply source 17b. The supply source 17b is in communication with the supply unit 15b. The supply source 17b stores an etching liquid Jb. The supply source 17b supplies the etching liquid Jb to the supply unit 15a.

[0203] The substrate processing apparatus 1 includes a pipe 18b and a valve 19b. The pipe 18b has a first end connected to a supply unit 15b. The pipe 18b has a second end connected to a supply source 17b. The valve 19b is provided on the pipe 18b. The valve 19b controls the supply of the etching liquid Jb by the supply unit 15b.

[0204] The supply units 15n, 15a, and 15b as a whole are an example of a supply unit in the present invention. The supply sources 17n, 17a, and 17b, the pipes 18n, 18a, and 18b, and the valves 19n, 19a, and 19b as a whole are an example of a switching unit in the present invention.

[0205] When there is no need to distinguish between the etchants Jn, Ja, and Jb, they will be referred to as "etchant J."

[0206] When there is no need to distinguish between the supply units 15n, 15a, and 15b, the supply units 15n, 15a, and 15b are collectively referred to as "supply unit 15."

[0207] The supply sources 17n, 17a, and 17b, the pipes 18n, 18a, and 18b, and the valves 19n, 19a, and 19b are collectively referred to as a "switching unit 60."

[0208] 12 is a control block diagram of the substrate processing apparatus 1 according to the second embodiment. The control unit 10 controls the switching unit 60. The control unit 10 controls the valves 19n, 19a, and 19b.

[0209] 2-2. Substrate processing method procedure 11 and 13 are referenced. FIG. 13 is a flowchart showing the procedure of a substrate processing method according to a second embodiment. The substrate processing method includes a conditioning step, an etching step, a rinsing step, and a drying step. The conditioning step is performed before the etching step. The etching step is performed after the conditioning step.

[0210] The operations of the rinsing step and the drying step are substantially the same between the first embodiment and the second embodiment, and therefore, a description of the rinsing step and the drying step will be omitted.

[0211] Step S4: Adjustment process In the adjusting step, the pH of the etching liquid J is adjusted. Specifically, the switching unit 60 changes the pH of the etching liquid J. The switching unit 60 changes the pH of the etching liquid J supplied to the supply unit 15.

[0212] As described above, the processing information defines the operation procedure of the processing unit 11. Therefore, in the adjustment step, the pH of the etching solution J is adjusted based on the processing information. The switching unit 60 changes the pH of the etching solution J based on the processing information.

[0213] For example, the switching unit 60 switches the etching liquid J among the etching liquids Jn, Ja, and Jb. The switching unit 60 switches the etching liquid J to one of the etching liquids Jn, Ja, and Jb. In this way, the switching unit 60 changes the pH of the etching liquid J.

[0214] Then, the switching unit 60 supplies one of the etching solutions Jn, Ja, and Jb to the supply unit 15. In this way, the switching unit 60 changes the pH of the etching solution J supplied to the supply unit 15.

[0215] When the switching unit 60 switches to the etching liquid Jn, the valve 19n opens, the valve 19a closes, and the valve 19b closes.

[0216] When the switching unit 60 switches to the etching liquid Ja, the valve 19a opens, the valve 19n closes, and the valve 19b closes.

[0217] When the switching unit 60 switches to the etching liquid Jb, the valve 19b opens, the valve 19n closes, and the valve 19a closes.

[0218] Step S1: Etching process In the etching step, the etching liquid J adjusted in the adjusting step is supplied to the substrate W.

[0219] Specifically, the supply unit 15 supplies one of the etching solutions Jn, Ja, and Jb to the substrate W held by the substrate holder 12. When the switching unit 60 switches the etching solution J among the etching solutions Jn, Ja, and Jb, the etching solution J supplied from the supply unit 15 to the substrate W switches among the etching solutions Jn, Ja, and Jb. As a result, the pH of the etching solution J supplied from the supply unit 15 to the substrate W changes.

[0220] 2-3. Technical significance of adjusting the pH of etching solution J The technical significance of adjusting the pH of the etching solution J will be explained using Example 3-7 and Comparative Example 3-7.

[0221] Before Examples 3-7 and Comparative Examples 3-7 were carried out, test pieces 40 and 50 were prepared. The test pieces 40 and 50 were as described above.

[0222] FIG. 14 shows the etching amounts H41 and H51, average etching rates avL41 and avM51, and SiO2 / SiN ratios N in Examples 1, 3, 5, and 7. FIG. 15 shows the etching amounts H41 and H51, average etching rates avL41 and avM51, and SiO2 / SiN ratios N in Examples 2, 4, and 6. FIG. 16 shows the etching amounts H41 and H51, average etching rates avL41 and avM51, and SiO2 / SiN ratios N in Comparative Examples 3, 5, and 7. FIG. 17 shows the etching amounts H41 and H51, average etching rates avL41 and avM51, and SiO2 / SiN ratios N in Comparative Examples 4 and 6. Note that Example 1 in FIG. 14 is the same as Example 1 in FIG. 9. Example 2 in FIG. 15 is the same as Example 2 in FIG. 10.

[0223] Examples 3-7 and Comparative Examples 3-7 will be described. The etching solutions used in Examples 1-7 and Comparative Examples 1-7 are different. Therefore, the etching solution used in Example 3 is referred to as "etching solution Ja1." The etching solution used in Example 5 is referred to as "etching solution Jb1." The etching solution used in Example 7 is referred to as "etching solution Jb2." The etching solution used in Example 4 is referred to as "etching solution Jb3." The etching solution used in Example 6 is referred to as "etching solution Jb4."

[0224] The etching solution of Comparative Example 3 is referred to as "etching solution Ka1". The etching solution of Comparative Example 5 is referred to as "etching solution Kb1". The etching solution of Comparative Example 7 is referred to as "etching solution Kb2". The etching solution of Comparative Example 4 is referred to as "etching solution Kb3". The etching solution of Comparative Example 6 is referred to as "etching solution Kb4".

[0225] After the test specimens 40 and 50 were processed in Example 3, the test specimens 40 and 50 were evaluated by etching rate. Similarly, after the test specimens 40 and 50 were processed in Examples 4-7, the test specimens 40 and 50 were evaluated by etching rate. After the test specimens 40 and 50 were processed in Comparative Examples 3-7, the test specimens 40 and 50 were evaluated by etching rate.

[0226] The definitions of the average etching rates avML41 and avM51 are as described above. The definition of the SiO2 / SiN ratio N is also as described above.

[0227] The conditions of Example 3 will be described. In the etching process, the etching solution Ja1 is supplied to the test pieces 40 and 50. The etching solution Ja1 contains hydrofluoric acid, heavy water, and a pH additive. The pH additive is hydrochloric acid. The hydrochloric acid has a concentration of 36 wt%. The volume ratio of hydrofluoric acid, heavy water, and hydrochloric acid in the etching solution Ja1 is as follows: Hydrofluoric acid: heavy water: hydrochloric acid = 1:28:1 (volume ratio) Other conditions in Example 3 are the same as those in Example 1.

[0228] In Example 3, the etching amount H41 was 34.32 nm, 68.60 nm, 102.92 nm, 136.28 nm, 169.54 nm, and 200.16 nm at each time the etching amount was obtained. The average etching rate avL41 was 6.81 nm / min.

[0229] In Example 3, the etching amount H51 was 3.24 nm, 6.23 nm, 9.51 nm, 12.49 nm, 15.43 nm, and 18.70 nm at each time the etching amount was obtained. The average etching rate avL51 was 0.53 nm / min.

[0230] In Example 3, the SiO2 / SiN ratio N was 13.03.

[0231] The conditions for Example 5 will be described. In the etching process, an etching solution Jb1 is supplied to the test pieces 40 and 50. The etching solution Jb1 contains hydrofluoric acid, heavy water, and a pH additive. The pH additive is ammonia water. The ammonia water has a concentration of 29 wt%. The volume ratio of hydrofluoric acid, heavy water, and ammonia water in the etching solution Jb1 is as follows: Hydrofluoric acid: heavy water: ammonia water = 1:28:1 (volume ratio) Other conditions in Example 5 are the same as those in Example 1.

[0232] In Example 5, the etching amounts H41 were 77.16 nm, 154.02 nm, 230.00 nm, 311.02 nm, 385.28 nm, and 460.00 nm at the times when the etching amounts were obtained. The average etching rate avL41 was 15.44 nm / min.

[0233] In Example 5, the etching amount H51 was 2.73 nm, 5.29 nm, 7.87 nm, 10.40 nm, 13.05 nm, and 15.69 nm at each time the etching amount was obtained. The average etching rate avL51 was 0.62 nm / min.

[0234] In Example 5, the SiO2 / SiN ratio N was 24.77.

[0235] The conditions of Example 7 will be described. In the etching process, the etching solution Jb2 is supplied to the test pieces 40 and 50. The etching solution Jb2 contains hydrofluoric acid, heavy water, and a pH additive. The pH additive is ammonia water. The ammonia water has a concentration of 29 wt%. The volume ratio of hydrofluoric acid, heavy water, and ammonia water in the etching solution Jb1 is as follows: Hydrofluoric acid: heavy water: ammonia water = 1:27:2 (volume ratio) Other conditions in Example 7 are the same as those in Example 1.

[0236] In Example 7, the etching amount H41 was 30.10 nm, 58.72 nm, 89.52 nm, 117.58 nm, 146.28 nm, and 175.14 nm at each time the etching amount was obtained. The average etching rate avL41 was 5.87 nm / min.

[0237] In Example 7, the etching amount H51 was 1.13 nm, 2.00 nm, 3.00 nm, 3.92 nm, 4.78 nm, and 5.86 nm at each time the etching amount was obtained. The average etching rate avL51 was 0.20 nm / min.

[0238] In Example 7, the SiO2 / SiN ratio N was 30.03.

[0239] The conditions for Example 4 will be described. In the etching process, an etching solution Jb3 is supplied to the test pieces 40 and 50. The etching solution Jb3 contains hydrofluoric acid, heavy water, and a pH additive. The pH additive is ammonia water. The ammonia water has a concentration of 29 wt%. The volume ratio of hydrofluoric acid, heavy water, and ammonia water in the etching solution Jb3 is as follows: Hydrofluoric acid: heavy water: ammonia water = 5:495.35:4.65 (volume ratio) Other conditions in Example 4 are the same as those in Example 1.

[0240] In Example 4, the etching amount H41 was 17.38 nm, 34.42 nm, 51.10 nm, 68.70 nm, 87.22 nm, and 104.02 nm at each time the etching amount was obtained. The average etching rate avL41 was 3.46 nm / min.

[0241] In Example 4, the etching amount H51 was 1.48 nm, 2.75 nm, 4.00 nm, 5.47 nm, 6.62 nm, and 7.86 nm at each time the etching amount was obtained. The average etching rate avL51 was 0.27 nm / min.

[0242] In Example 4, the SiO2 / SiN ratio N was 13.00.

[0243] The conditions for Example 6 will be described. In the etching process, etching solution Jb4 is supplied to the test pieces 40 and 50. The etching solution Jb4 contains hydrofluoric acid, heavy water, and a pH additive. The pH additive is ammonia water. The ammonia water has a concentration of 29 wt%. The volume ratio of hydrofluoric acid, heavy water, and ammonia water in the etching solution Jb4 is as follows: Hydrofluoric acid: heavy water: ammonia water = 5:490:10 (volume ratio) Other conditions in Example 6 are the same as those in Example 1.

[0244] In Example 6, the etching amount H41 was 4.88 nm, 9.98 nm, 14.88 nm, 20.04 nm, 24.42 nm, and 29.52 nm at each time the etching amount was obtained. The average etching rate avL41 was 0.99 nm / min.

[0245] In Example 6, the etching amount H51 was 0.66 nm, 0.77 nm, 1.19 nm, 1.75 nm, 2.05 nm, and 2.44 nm at each time the etching amount was obtained. The average etching rate avL51 was 0.08 nm / min.

[0246] In Example 6, the SiO2 / SiN ratio N was 11.91.

[0247] The conditions of Comparative Example 3 will be described. In the etching process, the etching solution Ka1 is supplied to the test pieces 40 and 50. The etching solution Ka1 contains hydrofluoric acid, deionized water, and a pH additive. The pH additive is hydrochloric acid. The hydrochloric acid has a concentration of 36 wt%. The volume ratio of hydrofluoric acid, deionized water, and hydrochloric acid in the etching solution Ka1 is as follows: Hydrofluoric acid: deionized water: hydrochloric acid = 1:28:1 (volume ratio) Other conditions in Comparative Example 3 are the same as those in Example 1.

[0248] In Comparative Example 3, the etching amount H41 was 49.08 nm, 99.22 nm, 141.96 nm, 186.60 nm, 234.82 nm, and 286.88 nm at each time the etching amount was obtained. The average etching rate avL41 was 9.43 nm / min.

[0249] In Comparative Example 3, the etching amount H51 was 4.02 nm, 7.68 nm, 11.35 nm, 15.13 nm, 18.87 nm, and 22.62 nm at each time the etching amount was obtained. The average etching rate avL51 was 0.74 nm / min.

[0250] In Comparative Example 3, the SiO2 / SiN ratio N was 12.68.

[0251] The conditions of Comparative Example 5 will be described. In the etching process, an etching solution Kb1 is supplied to the test pieces 40 and 50. The etching solution Kb1 contains hydrofluoric acid, deionized water, and a pH additive. The pH additive is ammonia water. The ammonia water has a concentration of 29 wt%. The volume ratio of hydrofluoric acid, deionized water, and ammonia water in the etching solution Kb1 is as follows: Hydrofluoric acid: deionized water: ammonia water = 1:28:1 (volume ratio) Other conditions in Comparative Example 5 are the same as those in Example 1.

[0252] In Comparative Example 5, the etching amount H41 was 77.36 nm, 149.00 nm, 222.88 nm, 298.50 nm, 371.56 nm, and 450.00 nm at each time the etching amount was obtained. The average etching rate avL41 was 14.89 nm / min.

[0253] In Comparative Example 5, the etching amount H51 was 3.91 nm, 7.49 nm, 11.25 nm, 14.87 nm, 18.60 nm, and 22.23 nm at each time the etching amount was obtained. The average etching rate avL51 was 0.76 nm / min.

[0254] In Comparative Example 5, the SiO2 / SiN ratio N was 19.70.

[0255] The conditions of Comparative Example 7 will be described. In the etching process, etching solution Kb2 is supplied to the test pieces 40 and 50. The etching solution Kb2 contains hydrofluoric acid, deionized water, and a pH additive. The pH additive is ammonia water. The ammonia water has a concentration of 29 wt%. The volume ratio of hydrofluoric acid, deionized water, and ammonia water in the etching solution Kb1 is as follows: Hydrofluoric acid: deionized water: ammonia water = 1:27:2 (volume ratio) Other conditions in Comparative Example 7 were the same as those in Example 1.

[0256] In Comparative Example 7, the etching amount H41 was 35.48 nm, 69.68 nm, 104.92 nm, 139.88 nm, 174.22 nm, and 206.42 nm at each time the etching amount was obtained. The average etching rate avL41 was 6.98 nm / min.

[0257] In Comparative Example 7, the etching amount H51 was 1.60 nm, 3.09 nm, 4.48 nm, 6.03 nm, 7.45 nm, and 8.91 nm at each time the etching amount was obtained. The average etching rate avL51 was 0.30 nm / min.

[0258] In Comparative Example 7, the SiO2 / SiN ratio N was 23.35.

[0259] The conditions of Comparative Example 4 will be described. In the etching process, the etching solution Kb3 is supplied to the test pieces 40 and 50. The etching solution Kb3 contains hydrofluoric acid, deionized water, and a pH additive. The pH additive is ammonia water. The ammonia water has a concentration of 29 wt%. The volume ratio of hydrofluoric acid, heavy water, and ammonia water in the etching solution Kb3 is as follows: Hydrofluoric acid: heavy water: hydrochloric acid = 5:495.35:4.65 (volume ratio) Other conditions in Comparative Example 4 are the same as those in Example 1.

[0260] In Comparative Example 4, the etching amount H41 was 19.30 nm, 35.88 nm, 53.38 nm, 71.26 nm, 88.94 nm, and 104.42 nm at each time the etching amount was obtained. The average etching rate avL41 was 3.53 nm / min.

[0261] In Comparative Example 4, the etching amount H51 was 1.87 nm, 3.49 nm, 5.12 nm, 6.85 nm, 8.48 nm, and 10.19 nm at each time the etching amount was obtained. The average etching rate avL51 was 0.34 nm / min.

[0262] In Comparative Example 4, the SiO2 / SiN ratio N was 10.36.

[0263] The conditions of Comparative Example 6 will be described. In the etching process, etching solution Kb4 is supplied to the test pieces 40 and 50. The etching solution Kb4 contains hydrofluoric acid, deionized water, and a pH additive. The pH additive is ammonia water. The ammonia water has a concentration of 29 wt%. The volume ratio of hydrofluoric acid, deionized water, and ammonia water in etching solution Kb2 is as follows: Hydrofluoric acid: deionized water: ammonia water = 5:490:10 (volume ratio) Other conditions in Comparative Example 6 are the same as those in Example 1.

[0264] In Comparative Example 6, the etching amount H41 was 4.56 nm, 8.64 nm, 13.24 nm, 17.98 nm, 22.58 nm, and 27.54 nm at each time the etching amount was obtained. The average etching rate avL41 was 0.90 nm / min.

[0265] In Comparative Example 6, the etching amount H51 was 0.50 nm, 1.03 nm, 1.55 nm, 2.06 nm, 2.54 nm, and 3.10 nm at each time the etching amount was obtained. The average etching rate avL51 was 0.10 nm / min.

[0266] In Comparative Example 6, the SiO2 / SiN ratio N was 8.77.

[0267] The following can be said from Examples 1-7.

[0268] 14. The SiO2 / SiN ratio N of Example 3 is larger than the SiO2 / SiN ratio N of Example 1. The SiO2 / SiN ratio N of Example 5 is larger than the SiO2 / SiN ratio N of Example 3. The SiO2 / SiN ratio N of Example 7 is larger than the SiO2 / SiN ratio N of Example 3.

[0269] 15. The SiO2 / SiN ratio N of Example 6 is larger than the SiO2 / SiN ratio N of Example 2. The SiO2 / SiN ratio N of Example 4 is larger than the SiO2 / SiN ratio N of Example 6.

[0270] See Fig. 14. The sums of the values ​​constituting the volume ratios of the etching solutions Jn1, Ja1, Jb1, and Jb2 are equal.

[0271] Therefore, in the second embodiment, it is easy to adjust the SiO2 / SiN ratio N by using the etching solutions Jn1, Ja1, Jb1, and Jb2.

[0272] See Fig. 15. The sums of the values ​​constituting the volume ratios of the etching solutions Jn2, Jb3, and Jb4 are equal.

[0273] Therefore, in the second embodiment, it is easy to adjust the SiO2 / SiN ratio N by using the etching solutions Jn2, Jb3, and Jb4.

[0274] 9, 10, and 14 to 17. The SiO2 / SiN ratio N of Example 7 is the highest among the SiO2 / SiN ratios N of Examples 1 to 7 and Comparative Examples 1 to 6.

[0275] 9, 14, and 16. The SiO2 / SiN ratio N of Example 7 is the highest among the SiO2 / SiN ratios N of Examples 1, 3, 5, and 7 and Comparative Examples 1, 3, 5, and 7.

[0276] 10, 15, and 17. The SiO2 / SiN ratio N of Example 4 is the highest among the SiO2 / SiN ratios N of Examples 2, 4, and 6 and Comparative Examples 2, 4, and 6.

[0277] The following can be said from Examples 1-7 and Comparative Examples 1-6.

[0278] Among the etching solutions Jn1, Jn2, Ja1, Jb1 to Jb4, Kn1, Kn2, Ka1, and Kb1 to Kb4, the etching solution Jb2 has the highest SiO2 / SiN ratio N. Therefore, in the second embodiment, by using the etching solution Jb2, it is easy to maximize the SiO2 / SiN ratio N.

[0279] Among the etching solutions Jn1, Ja1, Jb1, Jb2, Kn1, Ka1, Kb1, and Kb2, the etching solution Jb2 has the highest SiO2 / SiN ratio N. Therefore, in the second embodiment, by using the etching solution Jb2, it is easy to maximize the SiO2 / SiN ratio N.

[0280] Among the etching solutions Jn2, Jb3, Jb4, Kn2, Ka1, Kb3, and Kb4, the etching solution Jb3 has the highest SiO / SiN ratio N. Therefore, in the second embodiment, by using the etching solution Jb3, it is easy to maximize the SiO / SiN ratio N.

[0281] 2-4. Effects of the second embodiment The second embodiment also provides the same effects as the first embodiment. Furthermore, the second embodiment provides the following effects.

[0282] The etching solution Jn contains a pH adjuster, so that by using a pH adjuster in the etching solution Jn, it is easy to etch the first layer 31 more selectively.

[0283] The pH adjuster exhibits basicity, so it is easy to selectively etch the first layer 31 depending on the pH adjuster that exhibits basicity.

[0284] The pH adjuster exhibits acidity, so it is easy to selectively etch the first layer 31 depending on the pH adjuster that exhibits acidity.

[0285] The substrate processing method includes an adjusting step of adjusting the pH of the etching solution Jn. In the etching step, the etching solution Jn adjusted in the adjusting step is supplied to the substrate W. Therefore, in the adjusting step, the pH of the etching solution Jn is adjusted. Therefore, it is easy to adjust the ratio of the etching rate of the first layer 31 to the etching rate of the second layer 32. The "ratio of the etching rate of the first layer 31 to the etching rate of the second layer 32" is the SiO2 / SiN ratio N.

[0286] The substrate processing apparatus 1 includes a supply source 17n. The supply source 17n supplies the etching solution Jn to which a pH adjuster has been added to the supply unit 17. Therefore, by supplying the etching solution Jn to which a pH adjuster has been added, it is easy to further selectively etch the first layer 31.

[0287] The present invention is not limited to the embodiments, and can be modified as follows.

[0288] (1) In the first embodiment, the layout of the first layer 31 and the second layer 32 may be changed as appropriate. For example, the first layer 31 and the second layer 32 do not have to be in contact with each other. A third layer may be sandwiched between the first layer 31 and the second layer 32. A fourth layer may be sandwiched between the first layer 31 and the second layer 32. The third and fourth layers may be sandwiched between the first layer 31 and the second layer 32. A gap may be formed between the first layer 31 and the second layer 32.

[0289] The third layer may be made of, for example, silicon, which may be, for example, at least one of single crystal silicon, polycrystalline silicon (polysilicon), and amorphous silicon.

[0290] The third layer has etching resistance to, for example, the etchant Jn. For example, the etching resistance of the third layer is higher than that of at least one of the first layer 31 and the second layer 32.

[0291] The fourth layer may have a composition of, for example, at least one of titanium nitride, titanium, titanium oxide, and tungsten.

[0292] The fourth layer has etching resistance to, for example, the etchant Jn. For example, the etching resistance of the fourth layer is higher than that of at least one of the first layer 31 and the second layer 32.

[0293] (2) The supply unit 15, the switching unit 60, and the control unit 10 in the second embodiment may be modified as appropriate.

[0294] For example, the supply source 17n may be omitted. For example, the switching unit 60 may switch the etching liquid J between the etching liquids Ja and Jb. The etching liquid J supplied from the supply unit 15 to the substrate W may be switched between the etching liquids Ja and Jb.

[0295] For example, the supply source 17a may be omitted. For example, the switching unit 60 may switch the etching liquid J between the etching liquids Jn and Jb. The etching liquid J supplied from the supply unit 15 to the substrate W may be switched between the etching liquids Jn and Jb.

[0296] For example, the supply source 17b may be omitted. For example, the switching unit 60 may switch the etching liquid J between the etching liquids Jn and Ja. The etching liquid J supplied from the supply unit 15 to the substrate W may be switched between the etching liquids Jn and Ja.

[0297] (3) The switching unit 60 may generate at least one of the etching solutions Jn, Ja, and Jb.

[0298] 18 is a diagram showing the configuration of a processing unit 11 of the modified embodiment. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0299] The switching unit 60 includes a generator 70. The generator 70 generates an etchant Jn. The generator 70 generates an etchant Ja. The generator 70 generates an etchant Jb.

[0300] The generation unit 70 includes a mixing valve 71 and supply sources 72a, 72b, 77a, and 77b. The supply source 72a is connected to the mixing valve 71. The supply source 72b is connected to the mixing valve 71. The supply source 77a is connected to the mixing valve 71. The supply source 77b is connected to the mixing valve 71. The supply source 72a supplies hydrofluoric acid P to the mixing valve 71. The supply source 72b supplies heavy water Q to the mixing valve 71. The supply source 77a supplies a first pH adjuster Ra to the mixing valve 71. The first pH adjuster Ra is acidic. The supply source 77b supplies a second pH adjuster Rb to the mixing valve 71. The second pH adjuster Rb is basic.

[0301] The generation unit 70 includes a pipe 73a and a valve 74a. The pipe 73a has a first end connected to a mixing valve 71. The pipe 73a has a second end connected to a supply source 72a. The valve 74a is provided on the pipe 73a. The valve 74a controls the supply of hydrofluoric acid P from the supply source 72a to the mixing valve 71.

[0302] The generation unit 70 includes a pipe 73b and a valve 74b. The pipe 73b has a first end connected to the mixing valve 71. The pipe 73b has a second end connected to a supply source 72b. The valve 74b is provided on the pipe 73b. The valve 74b controls the supply of heavy water Q from the supply source 72b to the mixing valve 71.

[0303] The generation unit 70 includes a pipe 78a and a valve 79a. The pipe 78a has a first end connected to the mixing valve 71. The pipe 78a has a second end connected to a supply source 77a. The valve 79a is provided on the pipe 78a. The valve 79a controls the supply of the first pH adjuster Ra from the supply source 77a to the mixing valve 71.

[0304] The generation unit 70 includes a pipe 78b and a valve 79b. The pipe 78b has a first end connected to the mixing valve 71. The pipe 78b has a second end connected to a supply source 77b. The valve 79b is provided on the pipe 78b. The valve 79b controls the supply of the second pH adjuster Rb from the supply source 77b to the mixing valve 71.

[0305] When the generator 70 generates the etching solution Jn, the generator 70 dilutes hydrofluoric acid P with heavy water Q. Specifically, valves 74a and 74b are opened, and valves 79a and 79b are closed. The supply source 72a supplies hydrofluoric acid P to the mixing valve 71. The supply source 72b supplies heavy water Q to the mixing valve 71. The supply source 77a does not supply the first pH adjuster Ra to the mixing valve 71. The supply source 77b does not supply the second pH adjuster Rb to the mixing valve 71. The mixing valve 71 mixes the hydrofluoric acid P and the heavy water Q. As a result, the mixing valve 71 generates the etching solution Jn.

[0306] When the generator 70 generates the etching solution Ja, the generator 70 adds the first pH additive Ra to a solution obtained by diluting hydrofluoric acid P with heavy water Q. Specifically, valves 74a, 74b, and 79a are open, and valve 79b is closed. The supply source 72a supplies hydrofluoric acid P to the mixing valve 71. The supply source 72b supplies heavy water Q to the mixing valve 71. The supply source 77a supplies the first pH adjuster Ra to the mixing valve 71. The supply source 77b does not supply the second pH adjuster Rb to the mixing valve 71. The mixing valve 71 mixes the hydrofluoric acid P, the heavy water Q, and the first pH adjuster Ra. As a result, the mixing valve 71 generates the etching solution Ja.

[0307] When the generator 70 generates the etching solution Jb, the generator 70 adds the second pH additive Rb to a solution obtained by diluting hydrofluoric acid P with heavy water Q. Specifically, valves 74a, 74b, and 79b are open, and valve 79a is closed. The supply source 72a supplies hydrofluoric acid P to the mixing valve 71. The supply source 72b supplies heavy water Q to the mixing valve 71. The supply source 77a does not supply the first pH adjuster Ra to the mixing valve 71. The supply source 77b supplies the second pH adjuster Rb to the mixing valve 71. The mixing valve 71 mixes the hydrofluoric acid P, the heavy water Q, and the second pH adjuster Rb. As a result, the mixing valve 71 generates the etching solution Jb.

[0308] The substrate processing apparatus 1 includes a supply unit 15c, which is in communication with the generation unit .

[0309] Specifically, the switching unit 60 includes a pipe 81. The pipe 81 has a first end connected to the generation unit 70. The first end of the pipe 81 is connected to the mixing valve 71. The pipe 81 has a second end connected to the supply unit 15c.

[0310] The supply unit 15c includes, for example, one nozzle 16c. The nozzle 16c ejects the etching liquid Jn. The nozzle 16c ejects the etching liquid Ja. The nozzle 16c ejects the etching liquid Jb.

[0311] When the generator 70 generates the etching liquid Jn, the generator 70 supplies the etching liquid Jn to the supply unit 15c, and the supply unit 15c supplies the etching liquid Jn to the substrate W.

[0312] When the generator 70 generates the etching liquid Ja, the generator 70 supplies the etching liquid Ja to the supply unit 15c, and the supply unit 15c supplies the etching liquid Ja to the substrate W.

[0313] When the generator 70 generates the etching liquid Jb, the generator 70 supplies the etching liquid Jb to the supply unit 15c, and the supply unit 15c supplies the etching liquid Jb to the substrate W.

[0314] Although not shown in the figure, the control unit 10 controls the generation unit 70. The control unit 10 controls the valves 74a, 74b, 79a, and 79b.

[0315] The supply unit 15c is an example of the supply unit defined in the present invention.

[0316] According to the modified embodiment (3) above, the following effects are achieved.

[0317] The substrate processing apparatus 1 includes a generator 70. For example, the switching unit 60 includes the generator 70. The generator 70 is configured to generate the etchant Ja. The generator 70 is configured to supply the etchant Ja to the supply unit 15c. This makes it easy for the supply unit 15c to supply the etchant Ja to the substrate W. By generating the etchant Ja, it is easy to further selectively etch the layer 31.

[0318] (4) The configuration of the supply units 15n, 15a, and 15b may be changed as appropriate. At least two of the supply units 15n, 15a, and 15b may share the same nozzle. For example, the supply unit 15a may share the nozzle 16n of the supply unit 15n. For example, the supply unit 15b may share the nozzle 16n of the supply unit 15n. For example, the supply unit 15b may share the nozzle 16a of the supply unit 15a.

[0319] (5) The processing unit 11 may be classified as a batch processing unit, i.e., the processing unit 11 may process a plurality of substrates W at one time.

[0320] 19 is a diagram showing the configuration of a processing unit 11 of the modified embodiment. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0321] The processing unit 11 includes a tank 91. The tank 91 stores an etching solution J.

[0322] The processing unit 11 includes a substrate holder 92. The substrate holder 92 simultaneously holds a plurality of substrates W. The substrate holder 92 holds each substrate W in a substantially vertical position. When the substrate W is held by the substrate holder 92, the plane W1 is vertical.

[0323] The processing unit 11 includes a lifting / lowering drive unit 93. The lifting / lowering drive unit 93 is connected to the substrate holding unit 92. The lifting / lowering drive unit 93 moves the substrate holding unit 92 in the vertical direction Z. The substrate W held by the substrate holding unit 92 moves up and down integrally with the substrate holding unit 92. The lifting / lowering drive unit 93 moves the substrate holding unit 92 between an upper position and a lower position.

[0324] 19 shows the substrate holder 92 in the upper position by a dashed line. When the substrate holder 92 is in the upper position, the etching liquid J is not supplied to the substrate W. When the substrate holder 92 is in the upper position, the substrate W held by the substrate holder 92 is positioned above the etching liquid J in the tank 91.

[0325] 19 shows the substrate holder 92 in the lower position by a solid line. When the substrate holder 92 is in the lower position, the etching liquid J is supplied to the substrate W. When the substrate holder 92 is in the lower position, the substrate W held by the substrate holder 92 is immersed in the etching liquid J in the tank 91.

[0326] When the substrate holder 92 is in the down position, an etching process is performed.

[0327] The tank 91 is an example of a supply section in the present invention.

[0328] (6) The substrate processing methods of the first and second embodiments may be applied to the manufacture of various semiconductor products. The substrate processing apparatus 1 of the first and second embodiments may be used to manufacture various semiconductor products.

[0329] For example, the substrate processing methods of the first and second embodiments may be applied to the manufacture of a Fin Field-Effect Transistor (FinFET). For example, the substrate processing methods of the first and second embodiments may be applied to the formation of a recess structure. For example, the second layer 32 may be disposed in a trench. For example, the second layer 32 may be an isolation film. For example, the second layer 32 may be an insulator layer.

[0330] For example, the substrate processing methods of the first and second embodiments may be applied to a gate removal process. In the gate removal process, the gate is etched while the channel is protected from etching. The gate may be a dummy gate. The gate may have a film shape or a layer shape. The gate may be composed of, for example, silicon oxide or titanium nitride. The channel may be composed of, for example, silicon or germanium.

[0331] The substrate processing apparatus 1 of the first and second embodiments may perform the application examples of the substrate processing method described above.

[0332] (7) The first and second embodiments and the modified embodiments described above in (1) to (5) may be further modified as appropriate by replacing or combining each configuration with the configuration of another modified embodiment. [Explanation of symbols]

[0333] 1... Substrate processing equipment 10...Control section 11... Processing unit 12... Board holding part 15, 15n, 15a, 15b, 15c … Supply section 17n, 17a, 17b … Source 31 … 1st layer 32…Second layer 31S … 1st exposed surface 32S…Second exposed surface 60...Switching section 70 … Generation part 71...Mixing valve 72a, 72b … Source 77a, 77b … Source 91 … Tank (supply section) D31 … 1st exposure width D32 … 2nd exposure width E31 … 1st exposed area E32 … 2nd exposed area F31 … Direction F32 … Direction H31: Etching amount of the first layer H32: Etching amount of the second layer J, Jn, Ja, Jb...etchant avL41, avM51 ... Average etching rate N … SiO2 / SiN ratio P... Hydrofluoric acid Q … Heavy water Ra: 1st pH adjuster Rb: Second pH adjuster W: Substrate W1 … surface W2...face W3: Peripheral edge

Claims

1. A substrate processing method for processing a substrate, comprising: The substrate is a silicon oxide exposed surface where a silicon oxide layer made of silicon oxide is exposed; a silicon nitride exposed surface where a silicon nitride layer made of silicon nitride is exposed; Including, The substrate processing method includes: an etching step of supplying an etching solution containing hydrofluoric acid and heavy water to the substrate to selectively etch the exposed silicon oxide surface; Equipped with Substrate processing method.

2. 2. The substrate processing method according to claim 1, The etching solution contains a pH adjuster. Substrate processing method.

3. 3. The substrate processing method according to claim 2, The pH adjuster exhibits basicity. Substrate processing method.

4. 3. The substrate processing method according to claim 2, The pH adjuster exhibits acidity. Substrate processing method.

5. 3. The substrate processing method according to claim 2, The substrate processing method includes: an adjusting step of adjusting the pH of the etching solution; Equipped with In the etching step, the etching liquid adjusted in the adjusting step is supplied to the substrate. Substrate processing method.

6. A substrate processing apparatus, The substrate is a silicon oxide exposed surface where a silicon oxide layer made of silicon oxide is exposed; a silicon nitride exposed surface where a silicon nitride layer made of silicon nitride is exposed; Including, The substrate processing apparatus includes: a holder for holding the substrate; a supply unit that supplies an etching solution containing hydrofluoric acid and heavy water to the substrate held by the holder; Equipped with Substrate processing equipment.

7. 7. The substrate processing apparatus according to claim 6, a supply source that supplies the etching solution to which a pH adjuster has been added to the supply unit; Substrate processing equipment.

8. 7. The substrate processing apparatus according to claim 6, a generating unit that generates the etching solution to which a pH adjuster is added, The generating unit supplies the generated etching liquid to the supply unit. Substrate processing equipment.

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