Substrate processing method

Abstract

The present invention relates to a substrate processing method. The substrate processing method is for processing a substrate W. The substrate W includes a first layer E, a second layer F, and a third layer G. The third layer G is located between the first layer E and the second layer F. The first layer E has a composition that is different from the composition of the third layer G. The second layer F has a composition that is different from the composition of the third layer G. The substrate processing method includes a cycle step. The cycle step includes an etching step and a rinsing step. In the etching step, an etching liquid M is supplied to the substrate W. In the etching step, the third layer G is etched. A product P is generated by etching the third layer G. The rinsing step is carried out after the etching step. In the rinsing step, a rinsing liquid Q is supplied to the substrate W. In the rinsing step, the product P is removed from the substrate W. The cycle step is repeated two or more times.

Description

Substrate processing method

[0001] The present invention relates to a substrate processing method, and the substrate is, for example, any one of 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, and a solar cell substrate.

[0002] Patent Document 1 discloses a substrate processing method for processing a substrate, specifically, the substrate processing method is for etching the substrate.

[0003] The substrate includes a layer to be protected and a layer to be etched. The layer to be protected is made of silicon oxide. The layer to be etched is made of silicon nitride.

[0004] The substrate processing method includes a cycle process, which is repeated two or more times.

[0005] The cycle process includes a silylation process and an etching process. In the silylation process, a silylation agent is supplied to the substrate. The silylation agent is, for example, hexamethyldisilazane (HMDS). In the silylation process, the substrate is silylated. In the etching process, an etching solution is supplied to the substrate. The etching solution is, for example, hydrofluoric acid. In the etching process, the layer to be etched is etched. Specifically, in the etching process, silicon nitride is etched. In the etching process, the layer to be protected is not etched. Specifically, in the etching process, silicon oxide is not etched.

[0006] The cycle process further includes a rinsing process, in which a rinsing liquid, such as deionized water (DIW), is supplied to the substrate, and the etching liquid is removed from the substrate.

[0007] JP 2012-164949 A

[0008] Even with conventional substrate processing methods, it can be difficult to properly process a substrate. For example, a layer to be etched may be located between two layers to be protected. In this case, the etching rate of the layer to be etched is low. In particular, when the separation distance between the two layers to be protected is small, the etching rate of the layer to be etched is significantly low. For this reason, it is difficult to efficiently etch the layer to be etched. It takes a long time to etch the layer to be etched.

[0009] 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 that can process a substrate appropriately.

[0010] In order to achieve the above object, the present invention has the following configuration: That is, the present invention is a substrate processing method for processing a substrate, the substrate including a first layer, a second layer, and a third layer located between the first and second layers, the first layer having a composition different from that of the third layer, and the second layer having a composition different from that of the third layer, the substrate processing method comprising a cycle process including an etching process of supplying an etching liquid to the substrate and etching the third layer, and a rinsing process of supplying a rinsing liquid to the substrate after the etching process and removing a product produced by etching the third layer from the substrate, the cycle process being repeated two or more times.

[0011] A substrate processing method is for processing a substrate, the substrate including a first layer, a second layer, and a third layer, the third layer being positioned between the first layer and the second layer, the first layer having a composition different from that of the third layer, and the second layer having a composition different from that of the third layer.

[0012] The substrate processing method includes a cycle process. The cycle process includes an etching process and a rinsing process. In the etching process, an etching solution is supplied to the substrate. In the etching process, the third layer is etched. A product is generated by etching the third layer. The rinsing process is performed after the etching process. In the rinsing process, a rinsing solution is supplied to the substrate. In the rinsing process, the product is removed from the substrate.

[0013] The cycle step is repeated two or more times. Therefore, the rinsing step is performed two or more times. The products are repeatedly removed from the substrate. Therefore, it is easy to reduce the amount of products located between the first layer and the second layer. Therefore, the etching rate of the third layer is unlikely to decrease. As a result, it is easy to efficiently etch the third layer in the etching step.

[0014] The cycle process is repeated two or more times. Therefore, the etching process is performed two or more times. Therefore, it is easy to increase the total time of the multiple etching processes. Therefore, it is easy to properly etch the third layer. For example, it is easy to increase the total etching amount of the third layer in the multiple etching processes.

[0015] In summary, the third layer is efficiently etched by the substrate processing method, and therefore the substrate is appropriately processed by the substrate processing method.

[0016] In the above-described substrate processing method, the third layer is preferably repeatedly etched in a plurality of etching steps, so that the third layer is properly etched.

[0017] In the substrate processing method described above, it is preferable that the by-products are repeatedly removed from the substrate in the rinsing step. Therefore, the etching rate of the third layer is unlikely to decrease. Therefore, it is easy to efficiently etch the third layer in the etching step.

[0018] In the above-described substrate processing method, the cycle step is preferably repeated 10 or more times. Therefore, the product is repeatedly removed from the substrate 10 or more times. Therefore, the etching rate of the third layer is unlikely to decrease. Therefore, it is easy to efficiently etch the third layer in the etching step.

[0019] In the above-described substrate processing method, the product preferably has a composition derived from the composition of the third layer. Therefore, by removing the product from the substrate in the rinsing step, it is easy to prevent a decrease in the etching rate of the third layer. Therefore, it is easy to efficiently etch the third layer in the etching step.

[0020] In the above-described substrate processing method, it is preferable that the third layer is transformed into a product when the third layer is etched. Therefore, by removing the product from the substrate in the rinsing step, it is easy to prevent the product from transforming into the third layer. Therefore, it is easy to prevent a decrease in the etching rate of the third layer. Therefore, it is easy to efficiently etch the third layer in the etching step.

[0021] In the above-described substrate processing method, the third layer is preferably made of at least one of silicon oxide, titanium nitride, and silicon germanium, so that the third layer can be appropriately etched.

[0022] In the above-described substrate processing method, the product is H ２ SiF ６ , TiO ++ ・H ２ O ２ , H ２ Si(Ge)F ６ , SiO ３ ２－ , and GeO ３ ２－ Therefore, it is easy to prevent a decrease in the etching rate of the third layer by removing the by-product from the substrate in the rinsing step, and therefore it is easy to efficiently etch the third layer in the etching step.

[0023] In the above-described substrate processing method, the third layer is preferably made of silicon oxide, and the by-products contain silicon atoms. Therefore, by removing the by-products from the substrate in the rinsing step, it is easy to prevent a decrease in the etching rate of the third layer. Therefore, it is easy to efficiently etch the third layer in the etching step.

[0024] In the above-described substrate processing method, the third layer is made of silicon oxide, and the product is H ２ SiF ６ Therefore, it is easy to prevent a decrease in the etching rate of the third layer by removing the by-products from the substrate in the rinsing step, and therefore it is easy to efficiently etch the third layer in the etching step.

[0025] In the above-described substrate processing method, the third layer is preferably made of titanium nitride, and the by-products contain titanium atoms. Therefore, by removing the by-products from the substrate in the rinsing step, it is easy to prevent a decrease in the etching rate of the third layer. Therefore, it is easy to efficiently etch the third layer in the etching step.

[0026] In the above-described substrate processing method, the third layer is made of titanium nitride, and the product is TiO ++ ・H ２ O ２ Therefore, it is easy to prevent a decrease in the etching rate of the third layer by removing the by-products from the substrate in the rinsing step, and therefore it is easy to efficiently etch the third layer in the etching step.

[0027] In the above-described substrate processing method, the third layer is preferably made of silicon germanium, and the by-products include at least one of silicon atoms and germanium atoms. Therefore, by removing the by-products from the substrate in the rinsing step, it is easy to prevent a decrease in the etching rate of the third layer. Therefore, it is easy to efficiently etch the third layer in the etching step.

[0028] In the above-described substrate processing method, the third layer is made of silicon germanium, and the product is H ２ Si(Ge)F ６ , SiO ３ ２－ , and GeO ３ ２－ Therefore, it is easy to prevent a decrease in the etching rate of the third layer by removing the by-product from the substrate in the rinsing step, and therefore it is easy to efficiently etch the third layer in the etching step.

[0029] In the above-described substrate processing method, the third layer preferably does not contain silicon nitride, so that the third layer can be properly etched.

[0030] In the above-described substrate processing method, the separation distance between the first layer and the second layer is preferably 20 nm or less. When the separation distance is 20 nm or less, products tend to remain between the first layer and the second layer. Therefore, when the separation distance is 20 nm or less, it is useful to remove the products from the substrate in a rinsing step. When the separation distance is 20 nm or less, the effect of the rinsing step is significant.

[0031] In the above-described substrate processing method, the space in contact with the third layer is preferably as narrow as the separation distance or narrower than the separation distance. The space is in contact with the third layer. When the space is as narrow as the separation distance or narrower than the separation distance, the product is likely to remain in the space. Therefore, when the space is as narrow as the separation distance or narrower than the separation distance, it is useful to remove the product from the substrate in a rinsing step. When the space is as narrow as the separation distance or narrower than the separation distance, the effect of the rinsing step is significant.

[0032] In the above-described substrate processing method, it is preferable that the etching amount of the third layer in one etching step in one cycle process is equal to or less than a threshold value, and the threshold value is smaller than a target value of the total etching amount of the third layer. When the cycle process is repeated two or more times, the third layer is etched in multiple etching steps. The etching amount of the third layer in one etching step is equal to or less than the threshold value. The threshold value is smaller than the target value. That is, the etching amount of the third layer in one etching step is smaller than the target value. Here, the target value is the target value of the total etching amount of the third layer. The total etching amount of the third layer is the sum of the etching amounts of the third layer in all etching steps in all cycle processes. Therefore, it is easy to make the total etching amount of the third layer in multiple etching steps equal to the target value.

[0033] In the above-described substrate processing method, the target value is preferably equal to or greater than twice the threshold value, which makes it easier to make the total etching amount of the third layer in the multiple etching steps equal to the target value.

[0034] In the above-described substrate processing method, the threshold value is preferably 20 nm. Therefore, the etching amount of the third layer in one etching step in one cycle process is small. The amount of products generated in one etching step in one cycle process is small. Therefore, it is easy to reduce the amount of products located between the first and second layers. Therefore, the etching rate of the third layer is unlikely to decrease. As a result, it is easy to efficiently etch the third layer in the etching step.

[0035] In the above-described substrate processing method, the threshold value is preferably 10 nm. Therefore, the etching amount of the third layer in one etching step in one cycle process is smaller. The amount of products generated in one etching step in one cycle process is also smaller. Therefore, it is easier to reduce the amount of products located between the first and second layers. Therefore, the etching rate of the third layer is less likely to decrease. As a result, it is easier to efficiently etch the third layer in the etching step.

[0036] In the substrate processing method, the time for each etching step in each cycle is preferably determined based on the etching rate of the third layer. This makes it easy to control the amount of etching of the third layer in each etching step in each cycle. It also makes it easy to control the amount of product generated in each etching step in each cycle.

[0037] In the substrate processing method, the time for each etching step in each cycle is preferably determined based on the etching rate of the third layer and the threshold value. This makes it easy to control the amount of etching of the third layer in each etching step in each cycle. It also makes it easy to control the amount of product generated in each etching step in each cycle.

[0038] In the substrate processing method described above, it is preferable that the time of each etching step in each cycle is limited so that the etching amount of the third layer in each etching step in each cycle is equal to or less than the threshold value. Therefore, it is easy to control the etching amount of the third layer in each etching step in each cycle. It is also easy to control the amount of products generated in each etching step in each cycle.

[0039] In the substrate processing method, the number of times the cycle step is repeated is preferably determined based on the target value, so that the total etching amount of the third layer in the multiple etching steps can be easily made equal to the target value.

[0040] In the substrate processing method, the number of times the cycle process is repeated is preferably determined based on the target value and the etching amount of the third layer in one etching step in one cycle process, which makes it easier to make the total etching amount of the third layer in multiple etching steps equal to the target value.

[0041] In the above-described substrate processing method, it is preferable that the etching solution is supplied to the substrate in a dry state in the etching step, which makes it easy to supply etching ions to the third layer, and thus makes it easier to efficiently etch the third layer in the etching step.

[0042] Here, the etching ions are contained in the etching solution. The etching ions are ions that etch the third layer. The etching ions are not products.

[0043] In the substrate processing method described above, the cycle step preferably includes a drying step of drying the substrate, and the drying step is preferably performed after the rinsing step, so that it is easy to supply the etching solution to the dry substrate in the etching step.

[0044] In the above-described substrate processing method, it is preferable that the substrate is not dried in the cycle process. Therefore, the cycle process is simple. Therefore, the time required for one cycle process is short. Therefore, it is easy to repeat the cycle process.

[0045] In the above-described substrate processing method, the substrate processing method preferably further includes a final drying step of drying the substrate, and the cycle step is preferably repeated two or more times before the final drying step. Therefore, the cycle step does not include the final drying step. The cycle step is repeated without the final drying step. Therefore, the time required for one cycle step is short. Therefore, it is easy to repeat the cycle step.

[0046] According to the substrate processing method of the present invention, the substrate is properly processed.

[0047] FIG. 1 is a plan view showing the inside of a substrate processing apparatus. FIG. 2 is a control block diagram of a substrate processing apparatus. FIG. 3( a) is a side view of a substrate. FIG. 3( b) is a plan view of a substrate. FIGS. 4( a) and 4(b) are detailed views of a first layer, a second layer, and a third layer of a substrate, respectively. FIG. 2 is a diagram showing the configuration of a processing unit. FIG. 3 is a flowchart showing the procedure of a substrate processing method. FIG. 4 is a flowchart showing the procedure of a cycle process of a first embodiment. FIG. 4 is a flowchart showing the procedure of a substrate processing method of an example. FIG. 5 is a diagram showing a schematic view of a substrate in an etching process of a first cycle process of an example. FIG. 6 is a diagram showing a schematic view of a substrate in an etching process of a first cycle process of an example. FIG. 7 is a diagram showing a schematic view of a substrate in a rinsing process of a first cycle process of an example. FIG. 8 is a diagram showing a schematic view of a substrate in an etching process of a second cycle process of an example. FIG. 9 is a diagram showing a schematic view of a substrate in an etching process of a second cycle process of an example. FIG. 10 is a flowchart showing the procedure of a substrate processing method of a comparative example. FIG. 11 is a diagram showing a schematic view of a substrate W in an etching process of a comparative example. FIG. 12 is a flowchart showing the procedure of a cycle process of a second embodiment. 1A is a detailed view of the first, second and third layers of a substrate of a modified embodiment; 1B is a detailed view of the first, second and third layers of a substrate of another modified embodiment; 1C is a detailed view of the first, second and third layers of a substrate of another modified embodiment; 1D is a detailed view of the first, second and third layers of a substrate of another modified embodiment; 1E is a detailed view of the first, second and third layers of a substrate of another modified embodiment;

[0048] A substrate processing method and a substrate processing apparatus according to the present invention will be described below with reference to the drawings.

[0049] 1. First Embodiment 1-1. Overview of Substrate Processing Apparatus Fig. 1 is a plan view showing the interior of a substrate processing apparatus 1. The substrate processing apparatus 1 processes substrates W. The processes in the substrate processing apparatus 1 include wet etching. The wet etching is a process in which the substrate W is etched with an etching solution.

[0050] 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.

[0051] 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 simply 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, rear, right, left, top, and bottom are indicated as appropriate.

[0052] The indexer unit 3 includes a plurality of (for example, four) carrier platforms 4. Each carrier platform 4 has one carrier C mounted thereon. The carrier C accommodates a plurality of substrates W. The carrier C is, for example, a front-opening unified pod (FOUP), a standard mechanical interface (SMIF), or an open cassette (OC).

[0053] The indexer unit 3 includes a transport mechanism 5. The transport mechanism 5 transports substrates W. The transport mechanism 5 transports substrates W between a carrier C placed on the carrier platform 4 and a processing block 7. The transport mechanism 5 is disposed behind the carrier platform 4. The transport mechanism 5 is configured to approach the carrier C placed on the carrier platform 4. The transport mechanism 5 is configured to approach the processing block 7.

[0054] 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.

[0055] The processing block 7 includes a plurality of processing units 11. Each processing unit 11 performs processing on a substrate W.

[0056] Each processing unit 11 includes a substrate holder 13. The substrate holder 13 holds a substrate W.

[0057] The processing block 7 includes a transport mechanism 8. The transport mechanism 8 is arranged to the side of the processing unit 11. The transport mechanism 8 transports substrates W. The transport mechanism 8 transports substrates W between the indexer unit 3 and the processing unit 11. The transport mechanism 8 transports substrates W between the transport mechanism 5 and the substrate holder 13. The transport mechanism 8 is configured to approach the indexer unit 3. The transport mechanism 8 is configured to approach the processing unit 11.

[0058] 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.

[0059] 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 transport mechanisms 5 and 8 and the processing unit 11. The control unit 10 is communicatively connected to the transport mechanisms 5 and 8 and the processing unit 11.

[0060] The control unit 10 is realized by a central processing unit (CPU) that executes various processes, a random-access memory (RAM) that serves as a work area for the processes, and a storage medium such as a fixed disk. The control unit 10 has various types of information pre-stored in the storage medium. The information stored in the control unit 10 includes, for example, transport condition information and processing condition information. The transport condition information defines conditions related to the operation of the transport mechanisms 5 and 8. The processing condition information defines conditions related to the operation of the processing unit 11. The processing condition information is also called a processing recipe.

[0061] An example of the operation of the substrate processing apparatus 1 will now be briefly described.

[0062] The transport mechanism 5 takes out the substrate W from the carrier C on the carrier mount part 4. The transport mechanism 5 hands over the substrate W to the transport mechanism 8.

[0063] 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 13. The substrate holder 13 holds the substrate W.

[0064] Each processing unit 11 processes the substrate W held by the substrate holder 13. Each processing unit 11 performs wet etching on the substrate W, for example.

[0065] 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 13. The transport mechanism 8 hands the substrate W over to the transport mechanism 5.

[0066] The transport mechanism 5 loads the substrate W into the carrier C.

[0067] 1-2. Structure of the Substrate W The substrate W is, for example, any one of 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, and a solar cell substrate.

[0068] Fig. 3(a) is a side view of the substrate W. Fig. 3(b) is a plan view of the substrate W. The substrate W has a thin, flat plate shape. The substrate W has a substantially circular shape in a plan view.

[0069] The substrate W has a surface W1. The surface W1 has a substantially circular shape in a plan view. The surface W1 is substantially flat. The surface W1 is substantially flat.

[0070] 4(a) and 4(b) are each a detailed view of a portion of a substrate W. The substrate W includes a first layer E, a second layer F, and a third layer G. The first layer E, the second layer F, and the third layer G are each located on a surface W1. The first layer E and the second layer F are spaced apart from each other. The third layer G is located between the first layer E and the second layer F.

[0071] The first layer E has, for example, a plate shape. The first layer E has, for example, a film shape. The second layer F has, for example, a plate shape. The second layer F has, for example, a film shape. The third layer G has, for example, a plate shape. The third layer G has, for example, a film shape.

[0072] The third layer G is exposed. For example, the third layer G has a surface G1. The surface G1 does not contact the first layer E. The surface G1 does not contact the second layer F. The surface G1 is exposed.

[0073] Space A is adjacent to the third layer G. Space A is adjacent to face G1. Space A is located near the third layer G. Space A is located near face G1. Space A is an unoccupied space. The first layer E does not exist in space A. The second layer F does not exist in space A. The third layer G does not exist in space A.

[0074] Space A is small.

[0075] 4(a) and 4(b) show the separation distance D. The separation distance D is the distance between the first layer E and the second layer F. The separation distance D is small. For example, the separation distance D is 20 nm or less. For example, the separation distance D is 10 nm or less. For example, the separation distance D is several nm.

[0076] For example, the separation distance D corresponds to the width of the space A. For example, the width of the space A is equal to the separation distance D. For example, the space A is as narrow as the separation distance D.

[0077] For example, the first layer E, the second layer F, and the third layer G are stacked one on top of the other. For example, the first layer E, the second layer F, and the third layer G are stacked in this order.

[0078] For example, the third layer G contacts the first layer E and contacts the second layer F. For example, the third layer G extends from the first layer E to the second layer F.

[0079] The first layer E has a surface E1. The second layer F has a surface F1. The surfaces E1 and F1 are not in contact with each other. The surfaces E1 and F1 face each other. The surfaces E1 and F1 are, for example, parallel to each other. For example, the separation distance D corresponds to the separation distance between the surfaces E1 and F1. The third layer G is disposed between the surfaces E1 and F1.

[0080] For example, the surface E1 contacts the third layer G. For example, a portion of the surface E1 contacts the third layer G.

[0081] For example, the first layer E contacts the space A. For example, the surface E1 contacts the space A. For example, another portion of the surface E1 contacts the space A. The other portion of the surface E1 does not contact the third layer G. The other portion of the surface E1 is exposed.

[0082] For example, the surface F1 contacts the third layer G. For example, a portion of the surface F1 contacts the third layer G.

[0083] For example, the second layer F contacts the space A. For example, the face F1 contacts the space A. For example, another portion of the face F1 contacts the space A. The other portion of the face F1 does not contact the third layer G. The other portion of the face F1 is exposed.

[0084] 4(a) shows the third layer G before etching. FIG. 4(b) shows the third layer G after etching. The third layer G is etched. Specifically, the surface G1 is etched. The third layer G is selectively etched. The third layer G is etched while the first layer E and the second layer F are protected. The first layer E is not substantially etched. The second layer F is not substantially etched.

[0085] The third layer G is etched in a depth direction J. Specifically, the surface G1 is etched in the depth direction J. The depth direction J is, for example, perpendicular to the surface G1.

[0086] The third layer G has a length KG in the depth direction J. When the third layer G is etched, the length KG decreases.

[0087] Specifically, in Fig. 4(a), the third layer G has a length KG1. In Fig. 4(b), the third layer G has a length KG2. The length KG2 is shorter than the length KG1.

[0088] 4B shows the etching amount LG of the third layer G. The etching amount LG is, for example, the difference between the length KG1 and the length KG2.

[0089] The etching rate UG of the third layer G is the etching amount LG per unit time.

[0090] The first layer E has a composition different from that of the third layer G. The second layer F has a composition different from that of the third layer G.

[0091] The composition of the second layer F may be the same as the composition of the first layer E. Alternatively, the composition of the second layer F may be different from the composition of the first layer E.

[0092] The first layer E is made of, for example, at least one of single crystal silicon, polysilicon, amorphous silicon, silicon nitride, silicon oxide, and hafnium oxide.

[0093] The second layer F is made of, for example, at least one of single crystal silicon, polysilicon, amorphous silicon, silicon nitride, silicon oxide, and hafnium oxide.

[0094] The third layer G is made of at least one of silicon oxide, titanium nitride, and silicon germanium, but does not contain silicon nitride.

[0095] When at least one of the first layer E and the second layer F contains silicon oxide, the third layer G does not contain silicon oxide.

[0096] When at least one of the first layer E and the second layer F contains hafnium oxide, the third layer G does not contain silicon oxide and does not contain silicon germanium.

[0097] When the third layer G is made of silicon oxide, the first layer E does not contain silicon oxide, the first layer E does not contain hafnium oxide, the second layer F does not contain silicon oxide, and the second layer F does not contain hafnium oxide.

[0098] When the third layer G is made of silicon germanium, the first layer E does not contain hafnium oxide and the second layer F does not contain hafnium oxide.

[0099] Polycrystalline silicon is also called polysilicon.

[0100] Silicon oxide can be obtained by, for example, thermal oxidation, chemical vapor deposition (CVD), or atomic layer deposition (ALD). Silicon oxide obtained by thermal oxidation is sometimes called a "thermal oxide film."

[0101] 1-3. Configuration of Processing Unit 11 Fig. 5 is a diagram showing the configuration of the processing unit 11 in the first embodiment. Each processing unit 11 has the same structure. The processing units 11 are classified as single-wafer processing units. That is, each processing unit 11 processes only one substrate W at a time.

[0102] The processing unit 11 includes a housing 12. The housing 12 has a substantially box shape. The substrate W is processed inside the housing 12.

[0103] The substrate holder 13 is installed inside the housing 12. The substrate holder 13 holds only one substrate W at a time. The substrate holder 13 holds the substrate W in a substantially horizontal position. When the substrate W is held by the substrate holder 13, the surface W1 is horizontal.

[0104] When the substrate W is held by the substrate holder 13, the surface W1 faces upward. When the substrate W is held by the substrate holder 13, the surface W1 corresponds to the upper surface of the substrate W. The substrate holder 13 contacts at least one of the lower surface of the substrate W and the peripheral edge of the substrate W. The lower surface of the substrate W is also called the backside of the substrate W. The substrate holder 13 is located below the substrate W held by the substrate holder 13. The substrate holder 13 does not contact the surface W1.

[0105] The processing unit 11 includes a rotation drive unit 14. The rotation drive unit 14 is provided below the substrate holding unit 13. The rotation drive unit 14 is connected to the substrate holding unit 13. The rotation drive unit 14 rotates the substrate holding unit 13. The substrate W held by the substrate holding unit 13 rotates integrally with the substrate holding unit 13. The substrate W held by the substrate holding unit 13 rotates, for example, around a rotation axis B. The rotation axis B passes through the center of the substrate W, for example. The rotation axis B extends, for example, in the vertical direction Z.

[0106] The processing unit 11 includes a supply unit 15a. The supply unit 15a supplies an etching liquid to the substrate W. The supply unit 15a supplies the etching liquid to the substrate W held by the substrate holding unit 13. The supply unit 15a supplies the etching liquid to the surface W1 of the substrate W held by the substrate holding unit 13. In this way, the supply unit 15a etches the third layer G.

[0107] The etching solution includes, for example, at least one of hydrofluoric acid, dilute hydrofluoric acid (DHF), buffered hydrofluoric acid (BHF), hydrogen peroxide, hydrochloric acid, a mixture of hydrochloric acid and hydrogen peroxide, ammonium hydroxide, a mixture of ammonium hydroxide and hydrogen peroxide, a mixture of hydrofluoric acid, hydrochloric acid and hydrogen peroxide, a mixture of hydrofluoric acid and nitric acid, phosphoric acid, a mixture of phosphoric acid and nitric acid, a mixture of sulfuric acid and hydrogen peroxide, and tetramethylammonium hydroxide (TMAH).

[0108] It is preferable to select the composition of the etching solution depending on the composition of the third layer G.

[0109] For example, when the third layer G is made of silicon oxide, the etching solution is preferably at least one of hydrofluoric acid, dilute hydrofluoric acid (DHF), buffered hydrofluoric acid (BHF), hydrochloric acid, and ammonium hydroxide.

[0110] For example, when the third layer G is made of titanium nitride, the etching solution is preferably at least one of hydrofluoric acid, dilute hydrofluoric acid (DHF), buffered hydrofluoric acid (BHF), hydrochloric acid, ammonium hydroxide, phosphoric acid, a mixture of phosphoric acid and nitric acid, hydrogen peroxide, a mixture of sulfuric acid and hydrogen peroxide, a mixture of hydrochloric acid and hydrogen peroxide, and a mixture of ammonium hydroxide and hydrogen peroxide.

[0111] For example, when the third layer G is made of silicon germanium, it is preferable that the etching solution contains at least one of, for example, a mixture of hydrofluoric acid, hydrochloric acid, and hydrogen peroxide, a mixture of hydrofluoric acid and nitric acid, a mixture of phosphoric acid and nitric acid, and tetramethylammonium hydroxide.

[0112] The processing unit 11 includes a supply unit 15b. The supply unit 15b supplies a rinse liquid to the substrate W. The supply unit 15b supplies the rinse liquid to the substrate W held by the substrate holder 13. The supply unit 15b supplies the rinse liquid to a surface W1 of the substrate W held by the substrate holder 13.

[0113] The rinse liquid is, for example, deionized water (DIW) and / or isopropyl alcohol. The rinse liquid is also called a cleaning liquid.

[0114] The processing unit 11 includes a supply unit 15c. The supply unit 15c supplies a dry gas to the substrate W. The supply unit 15c supplies the dry gas to the substrate W held by the substrate holding unit 13. The supply unit 15c supplies the dry gas to a surface W1 of the substrate W held by the substrate holding unit 13.

[0115] The dry gas preferably has a dew point lower than the temperature inside the housing 12. The dry gas includes at least one of air and an inert gas. The air is, for example, compressed air. The inert gas is, for example, nitrogen gas.

[0116] The configurations of the supply units 15a, 15b, and 15c are illustrated. The supply unit 15a includes a nozzle 16a. The nozzle 16a is installed inside the housing 12. The nozzle 16a is disposed above the substrate W held by the substrate holder 13. The nozzle 16a ejects an etching liquid. Similarly, the supply units 15b and 15c include nozzles 16b and 16c, respectively. The nozzles 16b and 16c are installed inside the housing 12. The nozzle 16b ejects a rinse liquid. The nozzle 16c ejects a dry gas.

[0117] The supply unit 15a includes a pipe 17a and a valve 18a. The pipe 17a is connected to the nozzle 16a. At least a portion of the pipe 17a may be provided outside the housing 12. The valve 18a is provided in the pipe 17a. The valve 18a may be provided outside the housing 12. When the valve 18a is open, the nozzle 16a ejects the etching liquid. When the valve 18a is closed, the nozzle 16a does not eject the etching liquid. Similarly, the supply units 15b and 15c include pipes 17b and 17c and valves 18b and 18c, respectively. The pipes 17b and 17c are connected to the nozzles 16b and 16c, respectively. The valves 18b and 18c are provided in the pipes 17b and 17c, respectively. The valve 18b controls the ejection of the rinse liquid from the nozzle 16b. The valve 18c controls the ejection of the drying gas from the nozzle 16c.

[0118] Supply unit 15a is connected to supply source 19a. Supply source 19a delivers an etching liquid to supply unit 15a. Similarly, supplies 15b and 15c are connected to supply sources 19b and 19c, respectively. Supply source 19b delivers a rinsing liquid to supply unit 15b. Supply source 19c delivers a drying gas to supply unit 15c.

[0119] The supply source 19a is provided outside the housing 12. Similarly, the supply sources 19b and 19c are each provided outside the housing 12.

[0120] The supply source 19a may distribute the etching liquid to the supply parts 15a of the multiple processing units 11. Alternatively, the supply source 19a may supply the etching liquid exclusively to the supply part 15a of one processing unit 11. The same applies to the supply sources 19b and 19c.

[0121] The supply source 19a may be a component of the substrate processing apparatus 1. For example, the supply source 19a may be installed inside the substrate processing apparatus 1. Alternatively, the supply source 19a may not be a component of the substrate processing apparatus 1. For example, the supply source 19a may be installed outside the substrate processing apparatus 1. Similarly, at least one of the supply sources 19b and 19c may be a component of the substrate processing apparatus 1. Alternatively, at least one of the supply sources 19b and 19c may not be a component of the substrate processing apparatus 1.

[0122] The processing unit 11 may further include a cup (not shown). The cup is installed inside the housing 12. The cup is disposed on the side of the substrate holding part 13. The cup surrounds the substrate holding part 13. The cup catches liquid splashed from the substrate W held by the substrate holding part 13.

[0123] 2, the control unit 10 controls the rotary drive unit 14. The control unit 10 controls the supply units 15a-15c. The control unit 10 controls the valves 18a-18c.

[0124] 1-4. Example of Procedure of Substrate Processing Method The substrate processing method is performed in the processing unit 11. The substrate processing method is for processing the substrate W held by the substrate holder 13.

[0125] 6 is a flowchart showing the procedure of a substrate processing method. The substrate processing method includes a cycle process. The cycle process is repeated two or more times. For example, the cycle process is repeated ten or more times.

[0126] The substrate processing method includes a final drying step, which is performed after the cycle step is repeated two or more times. In other words, the cycle step is repeated two or more times before the final drying step.

[0127] Each step will be described below.

[0128] Step S1: Cycling Process The control unit 10 controls the supply units 15a and 15b to execute the cycling process. The control unit 10 causes the supply units 15a and 15b to repeat the cycling process two or more times.

[0129] 7 is a flowchart showing the procedure of the cycle process of the first embodiment. The cycle process of the first embodiment includes an etching process and a rinsing process. The rinsing process is performed after the etching process. The rinsing process is performed after the etching process.

[0130] Step S11: Etching Process In the etching process, an etching liquid is supplied to the substrate W. In the etching process, the third layer G is etched. Specifically, the control unit 10 controls the supply unit 15a to execute the etching process. In the etching process, the supply unit 15a supplies the etching liquid to the substrate W. In the etching process, the supply unit 15a etches the third layer G. A product is generated by etching the third layer G.

[0131] Step S12: First Rinse Process In the rinse process, a rinse liquid is supplied to the substrate W. In the rinse process, products generated by etching the third layer G are removed from the substrate W. Specifically, the control unit 10 controls the supply unit 15b to execute the rinse process. In the rinse process, the supply unit 15b supplies the rinse liquid to the substrate W. In the rinse process, the rinse liquid washes away the etching liquid on the substrate W. In the rinse process, the etching liquid is removed from the substrate W. In the rinse process, the rinse liquid washes away the products. In the rinse process, the products are removed from the substrate W.

[0132] The rinse liquid used in the rinse step may be only one of deionized water and isopropyl alcohol. For example, in the rinse step, deionized water may be supplied to the substrate W. In this case, the etching liquid on the substrate W is directly replaced with deionized water.

[0133] Alternatively, the rinse liquid used in the rinse step may be both deionized water and isopropyl alcohol. For example, in the rinse step, isopropyl alcohol may be supplied to the substrate W, and then deionized water may be supplied to the substrate W. In this case, the etching liquid on the substrate W is replaced with isopropyl alcohol, and then the isopropyl alcohol on the substrate W is replaced with deionized water. The etching liquid on the substrate W is indirectly replaced with deionized water.

[0134] When one cycle step ends, the next cycle step begins. Multiple cycle steps are performed consecutively. For example, the time when one cycle step ends is the same time when the next cycle step begins.

[0135] When the cycle process is repeated, the etching and rinsing steps are performed alternately.

[0136] When the cycle process is repeated two or more times, multiple etching steps are performed. The third layer G is repeatedly etched in multiple etching steps.

[0137] When the cycle process is repeated two or more times, multiple rinse processes are performed. The etching solution is repeatedly removed from the substrate W in multiple rinse processes. The products are repeatedly removed from the substrate W in multiple rinse processes.

[0138] Step S2: Final Drying Step In the final drying step, the substrate W is dried. Specifically, the control unit 10 controls at least one of the rotation drive unit 14 and the supply unit 15c to execute the final drying step. For example, in the final drying step, the rotation drive unit 14 rotates the substrate W held by the substrate holder 13. For example, in the final drying step, the supply unit 15c supplies a drying gas to the substrate W. This dries the substrate W.

[0139] In the cycle process, the rotation drive unit 14 may rotate the substrate W held by the substrate holding unit 13. In the etching process, the rotation drive unit 14 may rotate the substrate W held by the substrate holding unit 13. In the rinsing process, the rotation drive unit 14 may rotate the substrate W held by the substrate holding unit 13.

[0140] 1-5. Technical Significance of Repeating the Cyclic Process Two or More Times The technical significance of repeating the cyclic process two or more times will be explained using examples and comparative examples.

[0141] Conditions of the embodiment will be explained. FIG. 8 is a flowchart showing the procedure of the substrate processing method of the embodiment. In the embodiment, the cycle process is repeated twice. Specifically, in the embodiment, the cycle process includes a first cycle process and a second cycle process. The first cycle process is performed, and then the second cycle process is performed. The cycle process includes an etching process and a rinsing process. The first cycle process includes an etching process and a rinsing process. The second cycle process includes an etching process and a rinsing process. The etching process is performed twice. The rinsing process is performed twice.

[0142] A substrate W to be processed by the substrate processing method of the embodiment will be described.

[0143] Step S11: Etching step of first cycle process Figure 9 schematically shows a substrate W in the etching step of the first cycle process of the embodiment. Figure 9 schematically shows a substrate W at the start of the etching step of the first cycle process. In the etching step of the first cycle process, an etching liquid M is supplied to the substrate W. The etching liquid M enters the space A. The etching liquid M contacts the third layer G. The etching liquid M contacts the surface G1.

[0144] The etching solution M contains etching ions N. The etching ions N are dissolved in the etching solution M. The etching ions N are ions that etch the third layer G. The etching ions N are not products. The etching ions N are different from products generated by etching the third layer G.

[0145] When the etching solution is hydrofluoric acid, the etching ions N are, for example, bifluoride. The chemical formula of bifluoride is HF ２－ Bifluoride is an anion. Bifluoride is also called hydrogen difluoride ion.

[0146] Etching ions N enter space A. Etching ions N contact third layer G. Etching ions N adhere to third layer G. Etching ions N contact face G1. Etching ions N adhere to face G1.

[0147] The third layer G is etched with an etching solution M. The third layer G is etched with etching ions N.

[0148] 10 is a schematic diagram of the substrate W during the etching step of the first cycle step of the embodiment. Also, FIG. 10 is a schematic diagram of the substrate W at the end of the etching step of the first cycle step. During the etching step of the first cycle step, the third layer G is etched by an etching amount LGA1.

[0149] When the third layer G is etched, a product P is generated. The product P is generated by the reaction between the third layer G and the etching solution M. When the third layer G is etched, the third layer G changes into the product P. The product P is generated in the space A.

[0150] For example, when the third layer G is made of silicon oxide and the etching solution M is hydrofluoric acid, the reaction between the third layer G and the etching solution M is expressed by the following chemical reaction formula (1): SiO ２ +6HF=H ２ SiF ６ +2H ２ O (1) When the third layer G is etched with the etching solution M, the chemical reaction proceeds from the left side to the right side in the chemical reaction formula (1). As a result, the third layer G changes into a product P. When the third layer G is made of silicon oxide, the product P is H ２ SiF ６ Includes.

[0151] For example, when the third layer G is made of titanium nitride, the product P is TiO ++ ・H ２ O ２ For example, when the third layer G is made of silicon germanium, the product P includes H ２ Si(Ge)F ６ , SiO ３ ２－ , and GeO ３ ２－ It includes at least one of the following.

[0152] Therefore, the product P is H ２ SiF ６ , TiO ++ ・H ２ O ２ , H ２ Si(Ge)F ６ , SiO ３ ２－ , and GeO ３ ２－ It includes at least one of the following.

[0153] As described above, the product P has a composition derived from the composition of the third layer G. When the third layer G is made of silicon oxide, the product P contains silicon atoms. When the third layer G is made of titanium nitride, the product P contains titanium atoms. When the third layer G is made of silicon germanium, the product P contains silicon atoms and germanium atoms.

[0154] The reaction between the third layer G and the etching solution M is a reversible reaction. For example, the chemical reaction also proceeds from the right side to the left side in chemical reaction formula (1). That is, the product P changes into the third layer G. The product P returns to the third layer G. For example, when the third layer G is composed of silicon oxide, silicon oxide precipitates. When the product P changes into the third layer G, the third layer G is reproduced. When the product P changes into the third layer G, the etching rate UG of the third layer G decreases.

[0155] When the amount of product P located in space A is small, the concentration of product P in space A is low. Therefore, when the amount of product P located in space A is small, it is easy to move from the left side to the right side in chemical reaction formula (1). When the amount of product P located in space A is small, it is difficult to move from the right side to the left side in chemical reaction formula (1). Therefore, when the amount of product P located in space A is small, the etching rate UG is unlikely to decrease. When the amount of product P located in space A is small, it is easy to maintain the etching rate UG.

[0156] When the amount of product P located in space A is large, the concentration of product P in space A is high. Therefore, when the amount of product P located in space A is large, it is difficult to move from the left side to the right side in chemical reaction formula (1). When the amount of product P located in space A is large, it is easy to move from the right side to the left side in chemical reaction formula (1). Therefore, when the amount of product P located in space A is large, the etching rate UG is likely to decrease. When the amount of product P located in space A is large, it is difficult to maintain the etching rate UG.

[0157] When the space A is narrow, it is presumed that the fluidity of the etching solution M in the space A is low. For example, when the space A is narrow, it is presumed that the etching solution M in the space A has an ice-like structure. Therefore, when the space A is narrow, the product P is likely to remain in the space A. When the space A is narrow, it is difficult for the product P to move out of the space A. When the space A is narrow, the product P is likely to remain in the vicinity of the third layer G.

[0158] For example, when the separation distance D is 20 nm or less, it is presumed that the fluidity of the etching solution M in the space A is low. Therefore, when the separation distance D is 20 nm or less, the product P is likely to remain in the space A. When the separation distance D is 20 nm or less, the product P is unlikely to move outside the space A. When the separation distance D is 20 nm or less, the product P is likely to remain in the vicinity of the third layer G.

[0159] The greater the etching amount LG of the third layer G, the greater the amount of product P generated. The greater the amount of product P generated, the greater the amount of product P in the space A. Therefore, the greater the etching amount LG of the third layer G, the lower the etching rate UG.

[0160] Before the etching step of the first cycle step, no product P exists in the space A. Therefore, the amount of product P in the space A increases during the etching step of the first cycle step. Therefore, the etching rate UGA decreases during the etching step of the first cycle step. The etching rate UGA is the etching rate of the third layer G in this example.

[0161] The amount of product P in space A at the end of the etching process is greater than the amount of product P in space A at the start of the etching process. Therefore, the etching rate UGA1e is lower than the etching rate UGA1s. The etching rate UGA1s is the etching rate of the third layer G at the start of the etching process in the first cycle process of the example. The etching rate UGA1e is the etching rate of the third layer G at the end of the etching process in the first cycle process of the example.

[0162] Step S12: Rinse step of first cycle process Figure 11 shows a substrate W in the rinse step of the first cycle process of the embodiment. In the rinse step of the first cycle process, a rinse liquid Q is supplied to the substrate W. The rinse liquid Q enters the space A. The etchant M is removed from the space A. The etchant M is removed from the substrate W. The product P is removed from the space A. The product P is removed from the substrate W.

[0163] The amount of product P in space A decreases.

[0164] As a result, the amount of product P in space A is very small. At the end of the rinsing step, the amount of product P in space A is very small. For example, the amount of product P in space A is zero.

[0165] The concentration of product P in space A is very low. At the end of the rinsing step, the concentration of product P in space A is very low. For example, the concentration of product P in space A is zero.

[0166] Step S11: Etching step of second cycle process Fig. 12 schematically shows the substrate W in the etching step of the second cycle process of the embodiment. Fig. 12 schematically shows the substrate W at the start of the etching step of the second cycle process. In the etching step of the second cycle process, the etching liquid M is again supplied to the substrate W. The etching liquid M enters the space A. The etching liquid M contacts the third layer G. The etching liquid M contacts the surface G1.

[0167] Etching ions N enter space A. Etching ions N contact third layer G. Etching ions N contact face G1.

[0168] The third layer G is again etched with the etching solution M. The third layer G is again etched with the etching ions N.

[0169] At the start of the etching process of the second cycle step, the amount of product P in space A is very small. At the start of the etching process of the second cycle step, the concentration of product P in space A is very low. Therefore, it is easy to move from the left side to the right side in chemical reaction formula (1). It is difficult to move from the right side to the left side in chemical reaction formula (1). Therefore, the etching rate UGA2s is relatively high. The etching rate UGA2s is the etching rate of the third layer G at the start of the etching process of the second cycle step in the example.

[0170] The amount of product P in space A at the start of the etching step in the second cycle step is smaller than the amount of product P in space A at the end of the etching step in the first cycle step. Therefore, the etching rate UGA2s is higher than the etching rate UGA1e. Therefore, the etching rate UGA is improved from the etching rate UGA1e to the etching rate UGA2s.

[0171] 13 is a schematic diagram of the substrate W during the etching step of the second cycle step of the example. Also, FIG. 13 is a schematic diagram of the substrate W at the end of the etching step of the second cycle step. During the etching step of the second cycle step, the third layer G is etched by an etching amount LGA2.

[0172] The etching amount LGA is the sum of the etching amount LGA1 and the etching amount LGA2, and corresponds to the total etching amount of the third layer G in the multiple etching steps in this example.

[0173] By etching the third layer G, a product P is again produced.

[0174] Step S12: Rinse step of second cycle process Figure 14 schematically shows the substrate W in the rinse step of the second cycle process of the embodiment. In the rinse step of the second cycle process, the rinse liquid Q is again supplied to the substrate W. The etchant M is removed from the space A. The etchant M is removed from the substrate W. The product P is removed from the space A. The product P is removed from the substrate W.

[0175] As described above, the cycle process is repeated twice. Therefore, the etching process is performed twice. The etching process of the first cycle process and the etching process of the second cycle process are not consecutive in time. The rinsing process is performed twice. The rinsing process of the second cycle process is performed after the etching process of the first cycle process and before the etching process of the second cycle process. After the etching process of the first cycle process and before the etching process of the second cycle process, the product P is removed from the substrate W. Therefore, after the product P is generated, the product P is quickly removed from the substrate W. The time that the product P remains on the substrate W is short. Therefore, it is easy to reduce the amount of product P in the space A. It is easy to reduce the concentration of product P in the space A. Therefore, the etching rate UGA is unlikely to decrease. It is easy to prevent a decrease in the etching rate UGA. It is easy to maintain the etching rate UGA. As a result, it is easy to efficiently etch the third layer G in the etching process. Specifically, it is easy to etch the third layer G efficiently in the etching step of the first cycle process. It is easy to etch the third layer G efficiently in the etching step of the second cycle process.

[0176] The conditions of the comparative example will be described. Fig. 15 is a flowchart showing the procedure of the substrate processing method of the comparative example. In the comparative example, the etching step is performed only once. In the comparative example, the rinsing step is performed only once. In the comparative example, there is no cycle step repeated two or more times.

[0177] A substrate W processed by a substrate processing method of a comparative example will be described.

[0178] Step S21: Etching Process of Comparative Example For convenience, refer to Fig. 9. In the etching process of the comparative example, an etching solution M is supplied to the substrate W. The etching solution M enters the space A. Etching ions N enter the space A. The third layer G is etched with the etching solution M.

[0179] For convenience, refer to Figure 10. The third layer G is etched by an etching amount LGA1. A product P is generated. The amount of the product P in the space A increases.

[0180] 16 is a schematic diagram of the substrate W during the etching process of the comparative example. FIG. 16 is a schematic diagram of the substrate W at the end of the etching process of the comparative example. Subsequently, the third layer G is etched. The third layer G is further etched by an etching amount LGB2.

[0181] The etching amount LGB is the sum of the etching amount LGA1 and the etching amount LGB2, and corresponds to the total etching amount of the third layer G in one etching step in the comparative example.

[0182] Product P is further produced. The amount of product P in space A further increases.

[0183] At the end of the etching process of the comparative example, the amount of product P in space A is significantly large. At the end of the etching process of the comparative example, the concentration of product P in space A is significantly high. Therefore, in the etching process of the comparative example, the etching rate UGB of the third layer G is significantly reduced. The etching rate UGB is the etching rate of the third layer G in the comparative example.

[0184] Step S22: Rinsing Step of Comparative Example For convenience, reference will be made to Fig. 14. In the rinsing step of the comparative example, a rinsing liquid Q is supplied to the substrate W. The etching liquid M is removed from the space A. The etching liquid M is removed from the substrate W. The product P is removed from the space A. The product P is removed from the substrate W.

[0185] The differences between the Example and the Comparative Example will be summarized. The etching process time of the first cycle step of the Example is shorter than the etching process time of the Comparative Example. The etching process time of the second cycle step of the Example is shorter than the etching process time of the Comparative Example. The etching process time of the first cycle step of the Example corresponds to the time during which the product P remains on the substrate W in the Example. The etching process time of the second cycle step of the Example corresponds to the time during which the product P remains on the substrate W in the Example. The etching process time of the Comparative Example corresponds to the time during which the product P remains on the substrate W in the Comparative Example. Therefore, the time during which the product P remains on the substrate W in the Example is shorter than the time during which the product P remains on the substrate W in the Comparative Example.

[0186] The etching amount LGA1 of the example is smaller than the etching amount LGB of the comparative example. Therefore, the amount of product P generated in the etching process of the first cycle step of the example is smaller than the amount of product P generated in the etching process of the comparative example. The amount of product P in the space A at the end of the etching process of the first cycle step of the example is smaller than the amount of product P in the space A at the end of the etching process of the comparative example. Therefore, the etching rate UGA1e is higher than the etching rate UGBe. The etching rate UGBe is the etching rate of the third layer G at the end of the etching process of the comparative example.

[0187] Similarly, the etching amount LGA2 of the example is smaller than the etching amount LGB of the comparative example. Therefore, the amount of product P generated in the etching process of the second cycle step of the example is smaller than the amount of product P generated in the etching process of the comparative example. The amount of product P in the space A at the end of the etching process of the second cycle step of the example is smaller than the amount of product P in the space A at the end of the etching process of the comparative example. Therefore, the etching rate UGA2e is higher than the etching rate UGBe. The etching rate UGA2e is the etching rate of the third layer G at the end of the etching process of the second cycle step of the example.

[0188] Therefore, the etching rate UGA is higher than the etching rate UGB. The etching of the third layer G in the example is more efficient than the etching of the third layer G in the comparative example.

[0189] As a result, the total time for the multiple etching steps in the example may be shorter than the time for a single etching step in the comparative example. The processing time for the example may be shorter than the processing time for the comparative example. The etching amount LGA in the example may be greater than the etching amount LGB in the comparative example.

[0190] 1-6. Processing conditions for the cycle process Examples of processing conditions for the cycle process are given below.

[0191] The etching amount LGu is the etching amount of the third layer G in one etching step in one cycle process. The etching amount LGu is equal to or less than a threshold value V. The threshold value V is the upper limit of the etching amount LGu. The etching amount LGu is limited to be equal to or less than the threshold value V.

[0192] The total etching amount of the third layer G is the sum of the etching amounts of the third layer G in all etching steps in all cycle steps. For example, the total etching amount of the third layer G is the sum of all etching amounts LGu. The target value LGT is the target value of the total etching amount of the third layer G. More specifically, the "target value LGT" is the target value of the total etching amount of the third layer G in multiple etching steps. The threshold value V is smaller than the target value LGT. The etching amount LGu is smaller than the target value LGT. The etching amount LGu is limited to be less than the target value LGT. For example, the target value LGT is equal to or greater than twice the threshold value V. For example, the target value LGT is 100 nm. For example, the threshold value V is 20 nm. For example, the threshold value V is 10 nm.

[0193] The etching time Tu is the time required for one etching step in one cycle process, and is determined based on the etching rate UG of the third layer G.

[0194] The etching time Tu is determined based on the etching rate UG and a threshold value V. For example, the etching time Tu is limited so that the etching amount LGu is equal to or less than the threshold value V. For example, the etching time Tu is limited so that the integral of the etching rate UG with respect to the etching time Tu is equal to or less than the threshold value V. Here, the integral of the etching rate UG with respect to the etching time Tu corresponds to the etching amount LGu.

[0195] The number of times the cycle process is repeated is determined based on the target value LGT.

[0196] The number of times the cycle process is repeated is determined based on the target value LGT and the etching amount LGu. For example, the number of times the cycle process is repeated is the value obtained by dividing the target value LGT by the etching amount LGu. For example, when the target value LGT is 100 nm and the etching amount LGu is 2 nm, the number of times the cycle process is repeated is 50.

[0197] For example, in the cycling process, the substrate W is not dried.

[0198] 1-7. Effects of First Embodiment The substrate processing method of the first embodiment is for processing a substrate W. The substrate W includes a first layer E, a second layer F, and a third layer G. The third layer G is located between the first layer E and the second layer F. The first layer E has a different composition from the composition of the third layer G. The second layer F has a different composition from the composition of the third layer G.

[0199] The substrate processing method includes a cycle process. The cycle process includes an etching process and a rinsing process. In the etching process, an etching liquid M is supplied to the substrate W. In the etching process, the third layer G is etched. A product P is generated by etching the third layer G. The rinsing process is performed after the etching process. In the rinsing process, a rinsing liquid Q is supplied to the substrate W. In the rinsing process, the product P is removed from the substrate W.

[0200] The cycle process is repeated two or more times. Therefore, the rinse process is performed two or more times. The products P are repeatedly removed from the substrate W. Therefore, it is easy to reduce the amount of products P located between the first layer E and the second layer F. For example, it is easy to reduce the amount of products P in the space A. Therefore, the etching rate UG of the third layer G is unlikely to decrease. As a result, it is easy to efficiently etch the third layer G in the etching process.

[0201] The cycle process is repeated two or more times. Therefore, the etching process is performed two or more times. Therefore, it is easy to increase the total time of the multiple etching processes. Therefore, it is easy to properly etch the third layer G. For example, it is easy to increase the total etching amount of the third layer G in the multiple etching processes.

[0202] In summary, the substrate processing method of the first embodiment efficiently etches the third layer G. Therefore, the substrate W is appropriately processed by the substrate processing method.

[0203] The third layer G is repeatedly etched in a plurality of etching steps, so that the third layer G is properly etched.

[0204] The product P is repeatedly removed from the substrate W in multiple rinsing steps, which makes it difficult for the etching rate UG of the third layer G to decrease, and therefore it is easy to efficiently etch the third layer G in the etching step.

[0205] For example, the cycle process is repeated 10 or more times. Therefore, the product P is repeatedly removed from the substrate W 10 or more times. Therefore, the etching rate UG of the third layer G is unlikely to decrease. Therefore, it is easy to efficiently etch the third layer G in the etching process.

[0206] The product P has a composition derived from the composition of the third layer G. Therefore, by removing the product P from the substrate W in the rinsing step, it is easy to prevent a decrease in the etching rate UG of the third layer G. Therefore, it is easy to efficiently etch the third layer G in the etching step.

[0207] When the third layer G is etched, the third layer G changes into the product P. Therefore, by removing the product P from the substrate W in the rinsing step, it is easy to prevent the product P from changing into the third layer G. In other words, by removing the product P from the substrate W in the rinsing step, it is easy to prevent the product P from returning to the third layer G. Therefore, it is easy to prevent a decrease in the etching rate UG of the third layer G. Therefore, it is easy to efficiently etch the third layer G in the etching step.

[0208] The third layer G is made of at least one of silicon oxide, titanium nitride, and silicon germanium, and therefore can be appropriately etched.

[0209] The product P is H ２ SiF ６ , TiO ++ ・H ２ O ２ , H ２ Si(Ge)F ６ , SiO ３ ２－ , and GeO ３ ２－ Therefore, it is easy to prevent a decrease in the etching rate UG of the third layer G by removing the products P from the substrate W in the rinsing step. Therefore, it is easy to efficiently etch the third layer G in the etching step.

[0210] The third layer G is made of silicon oxide, and the product P contains silicon atoms. Therefore, by removing the product P from the substrate W in the rinsing step, it is easy to prevent a decrease in the etching rate UG of the third layer G. Therefore, it is easy to efficiently etch the third layer G in the etching step.

[0211] The third layer G is made of silicon oxide, and the product P is H ２ SiF ６ Therefore, it is easy to prevent a decrease in the etching rate UG of the third layer G by removing the products P from the substrate W in the rinsing step. Therefore, it is easy to efficiently etch the third layer G in the etching step.

[0212] The third layer G is made of titanium nitride, and the product P contains titanium atoms. Therefore, by removing the product P from the substrate W in the rinsing step, it is easy to prevent a decrease in the etching rate UG of the third layer G. Therefore, it is easy to efficiently etch the third layer G in the etching step.

[0213] The third layer G is made of titanium nitride, and the product P is TiO ++ ・H ２ O ２ Therefore, it is easy to prevent a decrease in the etching rate UG of the third layer G by removing the products P from the substrate W in the rinsing step. Therefore, it is easy to efficiently etch the third layer G in the etching step.

[0214] The third layer G is made of silicon germanium, and the product P contains at least one of silicon atoms and germanium atoms. Therefore, by removing the product P from the substrate W in the rinsing step, it is easy to prevent a decrease in the etching rate UG of the third layer G. Therefore, it is easy to efficiently etch the third layer G in the etching step.

[0215] The third layer G is made of silicon germanium, and the product P is H ２Si(Ge)F ６ , SiO ３ ２－ , and GeO ３ ２－ Therefore, it is easy to prevent a decrease in the etching rate UG of the third layer G by removing the products P from the substrate W in the rinsing step. Therefore, it is easy to efficiently etch the third layer G in the etching step.

[0216] The third layer G does not contain silicon nitride, so the third layer G can be etched appropriately.

[0217] The separation distance D between the first layer E and the second layer F is 20 nm or less. When the separation distance D is 20 nm or less, the product P is likely to remain between the first layer E and the second layer F. Therefore, when the separation distance D is 20 nm or less, it is useful to remove the product P from the substrate W in the rinse step. When the separation distance D is 20 nm or less, the effect of the rinse step is significant.

[0218] The space A contacts the third layer G. The space A is as narrow as the separation distance D. When the space A is as narrow as the separation distance D, the product P is likely to remain in the space A. Therefore, when the space A is as narrow as the separation distance D, it is useful to remove the product P from the substrate W in the rinse step. When the space A is as narrow as the separation distance D, the effect of the rinse step is significant.

[0219] When the cycle process is repeated two or more times, the third layer G is etched in multiple etching processes. The etching amount LGu of the third layer G in one etching process is equal to or less than the threshold value V. The threshold value V is smaller than the target value LGT. That is, the etching amount LGu is smaller than the target value LGT. Therefore, it is easy to make the total etching amount of the third layer G in multiple etching processes equal to the target value LGT.

[0220] The target value LGT is equal to or greater than twice the threshold value V. Therefore, it is easier to make the total etching amount of the third layer G in a plurality of etching steps equal to the target value LGT.

[0221] For example, the threshold value V is 20 nm. The etching amount LGu is 20 nm or less. Therefore, the etching amount LGu is small. The amount of product P generated in one etching step in one cycle process is small. Therefore, it is easy to reduce the amount of product P located between the first layer E and the second layer F. For example, it is easy to reduce the amount of product P in the space A. Therefore, the etching rate UG is unlikely to decrease. As a result, it is easy to efficiently etch the third layer G in the etching step.

[0222] For example, the threshold value V is 10 nm. The etching amount LGu is 10 nm or less. Therefore, the etching amount LGu is smaller. The amount of product P generated in one etching step in one cycle process is smaller. Therefore, it is easier to reduce the amount of product P located between the first layer E and the second layer F. For example, it is easier to reduce the amount of product P in the space A. Therefore, the etching rate UG is less likely to decrease. As a result, it is easier to efficiently etch the third layer G in the etching step.

[0223] The etching time Tu is the time required for one etching step in one cycle process. The etching time Tu is determined based on the etching rate UG. Therefore, it is easy to control the etching amount LGu. It is also easy to control the amount of product P generated in one etching step in one cycle process.

[0224] The etching time Tu is determined based on the etching rate UG and the threshold value V. Therefore, it is easy to control the etching amount LGu, and it is easy to control the amount of product P generated in one etching step in one cycle process.

[0225] The etching time Tu is limited so that the etching amount LGu is equal to or less than the threshold value V. Therefore, it is easy to control the etching amount LGu, and it is easy to control the amount of product P generated in one etching step in one cycle process.

[0226] The number of times the cycle process is repeated is determined based on the target value LGT, so it is easy to make the total etching amount of the third layer G in the multiple etching processes equal to the target value LGT.

[0227] The number of times the cycle process is repeated is determined based on the target value LGT and the etching amount LGu, making it easier to make the total etching amount of the third layer G in multiple etching processes equal to the target value LGT.

[0228] In the cycle process, the substrate W is not dried. Therefore, the cycle process is simple. Therefore, the time required for one cycle process is short. Therefore, the cycle process can be easily repeated.

[0229] The substrate processing method further includes a final drying step of drying the substrate W. The cycle step is repeated two or more times before the final drying step. Therefore, the cycle step does not include the final drying step. The cycle step is repeated without the final drying step. Therefore, the time required for one cycle step is short. Therefore, it is easy to repeat the cycle step.

[0230] 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.

[0231] The second embodiment is the same as the first embodiment in terms of the outline of the substrate processing apparatus 1, the structure of the substrate W, and the processing unit 11.

[0232] 2-1. Example of Procedure of Substrate Processing Method For convenience, reference will be made to FIG. 6. The substrate processing method of the second embodiment includes a cycle process and a final drying process. The final drying process of the second embodiment is the same as the final drying process of the first embodiment. The cycle process of the second embodiment is different from the cycle process of the first embodiment. Therefore, the cycle process of the second embodiment will be described.

[0233] 17 is a flowchart showing the procedure of the cycle process of the second embodiment. The cycle process of the second embodiment includes a drying process in addition to the etching process and the rinsing process. The drying process is performed after the rinsing process. The drying process is performed after the rinsing process.

[0234] The control unit 10 controls the supply units 15a, 15b, and 15c to execute the cycle process. The control unit 10 causes the supply units 15a, 15b, and 15c to repeat the cycle process two or more times.

[0235] Each step will be described below.

[0236] Step S11: Etching Step In the etching step, an etching liquid M is supplied to the substrate W. In the etching step, the third layer G is etched. By etching the third layer G, a product P is generated.

[0237] Step S12: Rinse Step In the rinse step, a rinse liquid Q is supplied to the substrate W. In the rinse step, the product P is removed from the substrate W.

[0238] Step S13: Drying Process In the drying process, the substrate W is dried. Specifically, the control unit 10 controls at least one of the rotation drive unit 14 and the supply unit 10e to execute the drying process. For example, in the drying process, the rotation drive unit 14 rotates the substrate W. For example, in the drying process, the supply unit 15c supplies a drying gas to the substrate W. This dries the substrate W.

[0239] 2-2. Technical Significance of Cycle Process Including Drying Process When the cycle process includes a drying process, in the etching process, the etching liquid M is supplied to the substrate W in a dry state. More specifically, in the etching process in the second or subsequent cycle process, the etching liquid M is supplied to the substrate W in a dry state. In the etching process performed after the drying process, the etching liquid M is supplied to the substrate W in a dry state.

[0240] When the etching liquid M is supplied to the dry substrate W, the etching ions N smoothly enter the space A. Therefore, it is easy to increase the amount of the etching ions N in the space A. It is easy to increase the concentration of the etching ions N in the space A.

[0241] For example, the amount of etching ions N in the space A when the etching liquid M is supplied to the dry substrate W is greater than the amount of etching ions N in the space A when the etching liquid M is supplied to the wet substrate W. For example, the concentration of etching ions N in the space A when the etching liquid M is supplied to the dry substrate W is greater than the concentration of etching ions N in the space A when the etching liquid M is supplied to the wet substrate W.

[0242] The wet substrate W is, for example, a substrate W wet with a rinse liquid Q. The wet substrate W is, for example, a substrate W wet with an etching liquid M.

[0243] Therefore, when the cycle process includes a drying process, it is easy to supply etching ions N to the third layer G. It is also easy to supply etching ions N to the surface G1. For example, the amount of etching ions N that contact the third layer G is relatively large. The amount of etching ions N that adhere to the third layer G is relatively large. The amount of etching ions N that contact the surface G1 is relatively large. The amount of etching ions N that adhere to the surface G1 is relatively large.

[0244] Therefore, when the cycle process includes a drying process, it is easy to etch the third layer G with the etching ions N. It is easy to etch the surface G1 with the etching ions N. Therefore, it is easy to improve the etching rate UG of the third layer G. As a result, it is easy to efficiently etch the third layer G in the etching process.

[0245] 2-3. Advantages of the Second Embodiment The second embodiment has advantages similar to those of the first embodiment. Furthermore, the second embodiment has the following advantages.

[0246] In the etching step, the etching liquid M is supplied to the dry substrate W. This makes it easy to supply etching ions N to the third layer G. This makes it even easier to efficiently etch the third layer G in the etching step.

[0247] The cycle process includes a drying process for drying the substrate W. The drying process is performed after the rinsing process. Therefore, it is easy to supply the etching liquid M to the substrate W in a dry state in the etching process. For example, it is easy to supply the etching liquid M to the substrate W in a dry state in the etching process in the second or subsequent cycle process.

[0248] The present invention is not limited to the embodiments, and can be modified as follows.

[0249] (1) In the first embodiment, a layout of the first layer E, the second layer F, and the third layer G is illustrated. In the first embodiment, the space A is as narrow as the separation distance D. However, the layout of the first layer E, the second layer F, and the third layer G is not limited to the example in the first embodiment. The relationship between the space A and the separation distance D is not limited to the example in the first embodiment. For example, the layout of the first layer E, the second layer F, and the third layer G may be changed as appropriate. For example, the space A may be narrower than the separation distance D. When the space A is narrower than the separation distance D, the product P is likely to remain in the space A. Therefore, when the space A is narrower than the separation distance D, it is useful to remove the product P from the substrate in the rinsing process. When the space A is narrower than the separation distance D, the effect of the rinsing process is significant.

[0250] Four modified examples will be described as modified embodiments with reference to the drawings.

[0251] (1-1) First Modified Example Fig. 18 is a detailed view of the first layer E, second layer F, and third layer G of the substrate W in a modified embodiment. Fig. 18 shows a space A in the modified embodiment. The third layer G is located between the first layer E and the second layer F. The third layer G contacts the first layer E and does not contact the second layer F.

[0252] Space A does not contact the first layer E. Space A contacts the second layer F. Space A contacts the third layer G. Space A is located between the second layer F and the third layer G. Space A is narrower than the separation distance D. The separation distance between the second layer F and the third layer G is smaller than the separation distance D.

[0253] (1-2) Second Modification Fig. 19 is a detailed view of the first layer E, second layer F, and third layer G of a substrate W in another modified embodiment. Fig. 19 shows a space A in another modified embodiment. The third layer G is located between the first layer E and the second layer F. The third layer G does not contact the first layer E, but contacts the second layer F.

[0254] Space A is adjacent to the first layer E. Space A is not adjacent to the second layer F. Space A is adjacent to the third layer G. Space A is located between the first layer E and the third layer G. Space A is narrower than the separation distance D. The separation distance between the first layer E and the third layer G is smaller than the separation distance D.

[0255] (1-3) Third Modification Figure 20 is a detailed view of the first layer E, second layer F, and third layer G of a substrate W in another modified embodiment. Figure 20 shows a space A in another modified embodiment. The third layer G is located between the first layer E and the second layer F. The third layer G does not contact the first layer E and does not contact the second layer F.

[0256] The space A includes a first space A1 and a second space A2. The first space A1 is adjacent to the first layer E. The first space A1 is not adjacent to the second layer F. The first space A1 is adjacent to the third layer G. The first space A1 is located between the first layer E and the third layer G. The first space A1 is narrower than the separation distance D. The separation distance between the first layer E and the third layer G is smaller than the separation distance D.

[0257] The space A includes a second space A2. The second space A2 does not contact the first layer E. The second space A2 contacts the second layer F. The second space A2 contacts the third layer G. The second space A2 is located between the second layer F and the third layer G. The second space A2 is narrower than the separation distance D. The separation distance between the second layer F and the third layer G is smaller than the separation distance D.

[0258] (1-4) Fourth Modification Figure 21 is a detailed view of the first layer E, second layer F, and third layer G of a substrate W in another modified embodiment. Figure 21 shows a space A in another modified embodiment. The third layer G is located between the first layer E and the second layer F. The third layer G contacts the first layer E and also contacts the second layer F. The third layer G does not extend from the first layer E to the second layer F. For example, the third layer G includes a first portion Ga and a second portion Gb. The first portion Ga and the second portion Gb are separated from each other. The first portion Ga contacts the first layer E and does not contact the second layer F. The second portion Gb does not contact the first layer E and contacts the second layer F.

[0259] Space A does not contact the first layer E. Space A does not contact the second layer F. Space A contacts the third layer G. Space A contacts the first portion Ga. Space A contacts the second portion Gb. Space A is located between the first portion Ga and the second portion Gb. Space A is narrower than the separation distance D. The separation distance between the first portion Ga and the second portion Gb is smaller than the separation distance D.

[0260] (2) The substrate processing method of the second embodiment includes the final drying step. However, the substrate processing method of the second embodiment does not necessarily include the final drying step.

[0261] (3) In the first and second embodiments, the processing units 11 are classified as single-wafer processing units. However, the processing units 11 are not limited to single-wafer processing units. For example, the processing units 11 may be classified as batch processing units. That is, the processing units 11 may process multiple substrates W at one time.

[0262] Although not shown in the figures, the processing unit 11 may include, for example, a first tank and a second tank. The first tank stores an etching liquid M. The second tank stores a rinsing liquid Q. In the etching process, multiple substrates W are immersed in the etching liquid M in the first tank. As a result, the etching liquid M is supplied to the multiple substrates W simultaneously. The third layers G of the multiple substrates W are etched simultaneously. In the rinsing process, multiple substrates W are immersed in the rinsing liquid Q in the second tank. As a result, the rinsing liquid Q is supplied to the multiple substrates W simultaneously. Products P are removed from the multiple substrates W simultaneously.

[0263] (4) The substrate processing methods of the first and second embodiments may be applied to the manufacture of various semiconductor products. For example, the substrate processing methods of the first and second embodiments may be applied to the manufacture of Fin Field-Effect Transistors (FinFETs). 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 third layer G may be disposed in a trench. For example, the third layer G may be an isolation film. For example, the third layer G may be an insulator layer.

[0264] (5) The first and second embodiments and the modified embodiments described above in (1) to (4) may be further modified as appropriate by replacing or combining each configuration with the configuration of another modified embodiment.

[0265] REFERENCE SIGNS LIST 1... substrate processing apparatus 10... control section 11... processing unit 13... substrate holder 15a... supply section 15b... supply section 15c... supply section A... space D... separation distance E... first layer F... second layer G... third layer G1... surface M... etchant N... etching ions P... product Q... rinse liquid LG... etching amount of third layer LGu... etching amount of third layer in one etching step in one cycle process LGT... target value of total etching amount of third layer Tu... time of one etching step in one cycle process UG... etching rate of third layer V... threshold W... substrate X... front-rear direction Y... width direction Z... vertical direction

Claims

1. A substrate processing method for processing a substrate, the substrate comprising: a first layer; a second layer; and a third layer located between the first layer and the second layer, the first layer having a composition different from a composition of the third layer, and the second layer having a composition different from a composition of the third layer, the substrate processing method comprising: a cycle process, the cycle process including: an etching process of supplying an etching liquid to the substrate and etching the third layer; and a rinsing process of supplying a rinsing liquid to the substrate after the etching process and removing a product generated by etching the third layer from the substrate, the cycle process being repeated two or more times.

2. The method of claim 1, wherein the third layer is transformed into a product when the third layer is etched.

3. A substrate processing method according to claim 1, wherein the third layer is made of at least one of silicon oxide, titanium nitride, and silicon germanium.

4. The substrate processing method according to claim 1, wherein the product is H ２ SiF ６ , TiO ++ ・H ２ O ２ , H ２ Si(Ge)F ６ , SiO ３ ２－ , and GeO ３ ２－ A substrate processing method comprising:

5. The method for processing a substrate according to claim 1, wherein the third layer does not contain silicon nitride.

6. A substrate processing method according to claim 1, wherein the separation distance between the first layer and the second layer is 20 nm or less.

7. A substrate processing method according to claim 1, wherein an etching amount of the third layer in one of the etching steps in one of the cycle steps is equal to or less than a threshold value, and the threshold value is smaller than a target value for a total etching amount of the third layer.

8. The substrate processing method according to claim 7, wherein the threshold value is 20 nm.

9. The substrate processing method according to claim 1, wherein in the etching step, an etching liquid is supplied to the substrate in a dry state.

10. The substrate processing method according to claim 1, wherein the cycle step includes a drying step of drying the substrate, the drying step being performed after the rinsing step.

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