Substrate processing method

Abstract

To provide a substrate processing method that can properly process substrates. [Solution] The present invention relates to a substrate processing method for processing a substrate W. The substrate processing method comprises a developing step, a processing solution supply step, a solidification film formation step, and a sublimation step. In the developing step, a developing solution 53 is supplied to the substrate W. In the processing solution supply step, a processing solution 55 is supplied to the substrate. The processing solution 55 contains a sublimable substance and a solvent. In the solidification film formation step, the solvent of the processing solution evaporates from the processing solution 55 on the substrate W. In the solidification film formation step, a solidification film 57 is formed on the substrate W. The solidification film 57 contains a sublimable substance. In the sublimation step, the solidification film 57 sublimes.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a substrate processing method for processing a substrate. Specifically, the substrate processing method of Patent Document 1 includes a processing liquid supply step, a solid film formation step, and a sublimation step. In the processing liquid supply step, the processing liquid is supplied to the substrate. The processing liquid contains a solvent and a sublimable substance. In the solid film formation step, the solvent evaporates, and a solid film is formed on the substrate. In the sublimation step, the solid film sublimates. Specifically, the solid film changes to a gas without going through a liquid state. The substrate is dried.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Even with conventional substrate processing methods, there are cases where the substrate cannot be properly processed. For example, even with conventional substrate processing methods, there are cases where the substrate cannot be properly dried.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a substrate processing method capable of properly processing a substrate.

Means for Solving the Problems

[0006] To achieve this objective, the present invention has the following configuration. That is, the present invention is a substrate processing method for processing a substrate, comprising: a developing step of supplying a developer to the substrate; a processing solution supply step of supplying a processing solution containing a sublimable substance and a solvent to the substrate; a solidification film forming step of evaporating the solvent from the processing solution on the substrate to form a solidified film containing the sublimable substance on the substrate; and a sublimation step of sublimating the solidified film.

[0007] The substrate processing method is for processing a substrate. The substrate processing method comprises a developing step, a processing solution supply step, a solidification film formation step, and a sublimation step. In the developing step, a developing solution is supplied to the substrate. In the processing solution supply step, a processing solution is supplied to the substrate. The processing solution contains a sublimable substance and a solvent. In the solidification film formation step, the solvent evaporates from the processing solution on the substrate. In the solidification film formation step, a solidification film is formed on the substrate. The solidification film contains a sublimable substance. In the sublimation step, the solidification film sublimes. The substrate is dried by the sublimation of the solidification film.

[0008] As described above, this substrate processing method includes a developing step. Therefore, this substrate processing method allows for proper processing of the substrate. Specifically, according to this substrate processing method, a developing solution is supplied to the substrate, and then the substrate is properly dried.

[0009] In the substrate processing method described above, it is preferable that the processing solution supply step is performed after the developing step, the solidification film formation step is performed after the processing solution supply step, and the sublimation step is performed after the solidification film formation step. Therefore, the substrate processing method can properly process the substrate.

[0010] In the substrate processing method described above, it is preferable that a resist pattern is formed on the substrate in the developing step. Therefore, in the processing solution supply step, the solidification film formation step, and the sublimation step, the substrate has a resist pattern. In the processing solution supply step, the processing solution is supplied to the substrate having the resist pattern. Even if the substrate has a resist pattern, the substrate is properly processed in the processing solution supply step, the solidification film formation step, and the sublimation step. For example, in the processing solution supply step, the solidification film formation step, and the sublimation step, the substrate is dried while the resist pattern is suitably protected. Rather, this substrate processing method is particularly effective when the resist pattern is formed on the substrate in the developing step.

[0011] In the substrate processing method described above, it is preferable that the resist pattern contains metal oxide. Therefore, the substrate is processed more appropriately in the processing liquid supply step, the solidification film formation step, and the sublimation step. For example, in the processing liquid supply step, the solidification film formation step, and the sublimation step, the substrate is dried while the resist pattern is more preferably protected.

[0012] In the substrate processing method described above, the sublimable substance preferably contains at least one of cyclohexanone oxime and camphor. Therefore, the substrate is properly processed in the processing liquid supply step, the solidification film formation step, and the sublimation step. For example, the substrate is properly dried in the processing liquid supply step, the solidification film formation step, and the sublimation step.

[0013] In the substrate processing method described above, the solvent preferably contains isopropyl alcohol. Therefore, the substrate is properly processed in the processing liquid supply step, the solidification film formation step, and the sublimation step. For example, the substrate is properly dried in the processing liquid supply step, the solidification film formation step, and the sublimation step.

[0014] In the substrate processing method described above, it is preferable to include a replacement step in which a replacement solution is supplied to the substrate after the developing step and before the processing solution supply step. In this replacement step, the developer on the substrate is replaced with the replacement solution. That is, in the replacement step, the developer is removed from the substrate. Thus, in the processing solution supply step, the processing solution is appropriately supplied to the substrate.

[0015] In the substrate processing method described above, it is preferable that the displacement solution has the same composition as the solvent. Therefore, the displacement solution has a high affinity for the processing solution. Thus, in the processing solution supply step, the processing solution is supplied to the substrate more appropriately.

[0016] In the substrate processing method described above, it is preferable to include an exposure step in which the substrate is exposed to light before the development step. Even if the substrate is exposed in the exposure step, the substrate is processed appropriately. Rather, when the substrate processing method includes an exposure step, the substrate processing method exhibits remarkable effects.

[0017] In the substrate processing method described above, it is preferable that the substrate is exposed to extreme ultraviolet light during the exposure step. This ensures that the substrate is processed more effectively.

[0018] In the substrate processing method described above, it is preferable that a pattern is transferred to the resist film on the substrate during the exposure step. Therefore, it is easy to form a resist pattern on the substrate during the development step. As described above, even if a resist pattern is formed on the substrate during the development step, the substrate is properly processed during the processing solution supply step, the solidification film formation step, and the sublimation step.

[0019] In the substrate processing method described above, it is preferable to include a first heating step in which the substrate is heated after the exposure step and before the development step. Therefore, the substrate is properly developed in the development step.

[0020] In the above-described substrate processing method, it is preferable to include a resist film forming step of forming a resist film on the substrate before the exposure step. Even when a resist film is formed on the substrate in the resist film forming step, the substrate is appropriately processed. Rather, when the substrate processing method includes the resist film forming step, this substrate processing method exhibits remarkable effects.

[0021] In the above-described substrate processing method, it is preferable that the resist film contains a metal oxide. For this reason, the substrate is more appropriately processed. For example, in the treatment liquid supply step, the solid film forming step, and the sublimation step, the substrate is more appropriately dried.

[0022] In the above-described substrate processing method, it is preferable to include a second heating step of heating the substrate after the resist film forming step and before the exposure step. Thus, in the exposure step and the development step, the substrate is more appropriately processed.

Advantages of the Invention

[0023] According to the substrate processing method of the present invention, the substrate can be appropriately processed.

Brief Description of the Drawings

[0024] [Figure 1] It is a plan view showing the inside of the substrate processing apparatus of the embodiment. [Figure 2] It is a side view showing the configuration of one side portion of the substrate processing apparatus. [Figure 3] It is a flowchart showing the procedure of the substrate processing method. [Figure 4] It is a diagram schematically showing a part of the substrate in the resist film forming step. [Figure 5] It is a diagram schematically showing a part of the substrate in the exposure step. [Figure 6] It is a diagram schematically showing a part of the substrate in the development step. [Figure 7] It is a diagram schematically showing a part of the substrate in the replacement step. [Figure 8]This diagram schematically shows a portion of the substrate during the processing liquid supply process. [Figure 9] This diagram schematically shows a portion of the substrate during the solidification film formation process. [Figure 10] This diagram schematically shows a portion of the substrate during the solidification film formation process. [Figure 11] This diagram schematically shows a portion of the substrate during the sublimation process. [Figure 12] This diagram schematically shows a portion of the substrate during the sublimation process. [Figure 13] This graph shows the evaluation of the substrates treated in the example and the substrates treated in the comparative example. [Modes for carrying out the invention]

[0025] The substrate processing method of the present invention will be described below with reference to the drawings.

[0026] <1. Overview of substrate processing equipment> Figure 1 is a plan view showing the interior of the substrate processing apparatus 1 of the embodiment. The substrate processing apparatus 1 processes a substrate W. The substrate W is, for example, a semiconductor wafer, a substrate for liquid crystal displays, an organic EL (electroluminescence) substrate, an FPD (flat panel display) substrate, an optical display substrate, a magnetic disk substrate, an optical disk substrate, a magneto-optical disk substrate, a photomask substrate, or a solar cell substrate. The substrate W has a thin, flat shape. The substrate W has a substantially circular shape in plan view.

[0027] The substrate processing apparatus 1 comprises an indexer unit 3 and a processing unit 5. The processing unit 5 is located to the side of the indexer unit 3. The processing unit 5 is connected to the indexer unit 3. The processing unit 5 is connected to the exposure unit 9. The indexer unit 3 transports the substrate W to the processing unit 5. The processing unit 5 processes the substrate W. The exposure unit 9 exposes the substrate W. The exposure unit 9 may be an element of the substrate processing apparatus 1. Alternatively, the exposure unit 9 may not be an element of the substrate processing apparatus 1.

[0028] The indexer unit 3 includes a plurality (for example, four) of carrier mounting units 11. Each carrier mounting unit 11 mounts one carrier C. The carrier C accommodates multiple substrates W. The carrier C is, for example, a FOUP (Front Opening Unified Pod), SMIF (Standard Mechanical Interface), or OC (Open Cassette).

[0029] The indexer unit 3 includes a transport mechanism 12. The transport mechanism 12 transports the substrate W between the carrier C, which is placed on the carrier mounting unit 11, and the processing unit 5.

[0030] The processing unit 5 comprises a plurality of processing units 13, 14, 15, and 16. Each of the processing units 13-16 performs processing on the substrate W. For example, processing unit 13 forms a resist film on the substrate W. Processing unit 14 heats the substrate W. Processing unit 15 heats the substrate W. Processing unit 16 supplies a developer solution to the substrate W.

[0031] The processing unit 5 includes a transport mechanism 17. The transport mechanism 17 transports the substrate W to the transport mechanism 12. The transport mechanism 17 transports the substrate W to the processing units 13-16. Furthermore, the transport mechanism 17 transports the substrate W to the exposure machine 9.

[0032] The substrate processing apparatus 1 may further include an interface unit (not shown). The interface unit is located between the processing unit 5 and the exposure machine 9. The interface unit transports the substrate W between the processing unit 5 and the exposure machine 9.

[0033] A brief explanation of the operation of the substrate processing device 1 is provided below. The transport mechanism 12 transports the substrate W from the carrier C to the transport mechanism 17.

[0034] The transport mechanism 17 transports the substrate W from the transport mechanism 12 to the processing unit 13. The processing unit 13 forms a resist film on the substrate W. The transport mechanism 17 transports the substrate W from the processing unit 13 to the processing unit 14. The processing unit 14 heats the substrate W. The transport mechanism 17 transports the substrate W from the processing unit 14 to the exposure machine 9.

[0035] The exposure unit 9 exposes the substrate W.

[0036] The transport mechanism 17 transports the substrate W from the exposure machine 9 to the processing unit 15. The processing unit 15 heats the substrate W. The transport mechanism 17 transports the substrate W from the processing unit 15 to the processing unit 16. The processing unit 16 supplies developer to the substrate W. The transport mechanism 17 transports the substrate W from the processing unit 16 to the transport mechanism 12.

[0037] The transport mechanism 12 transports the substrate W from the transport mechanism 17 to the carrier C.

[0038] <2. Example configuration of processing unit and exposure machine> Figure 2 is a side view showing the configuration of one side of the substrate processing apparatus 1. In Figure 2, processing units 13-16 are arranged on one side of the substrate processing apparatus 1 for convenience. However, the arrangement of processing units 13-16 may be changed as appropriate.

[0039] The processing unit 13 will now be described. The processing unit 13 includes a basic holding unit 21. The substrate holding unit 21 holds one substrate W in a substantially horizontal position.

[0040] The processing unit 13 includes a rotary drive unit 22. The rotary drive unit 22 is connected to the substrate holding unit 21. The rotary drive unit 22 rotates the substrate holding unit 21. The substrate W held by the substrate holding unit 21 rotates together with the substrate holding unit 21.

[0041] The processing unit 13 includes a nozzle 23. The nozzle 23 supplies a resist film material to the substrate W held by the substrate holding unit 21.

[0042] The resist film material supplied by the nozzle 23 will be described. The resist film material is classified, for example, as a negative-type resist film material.

[0043] The resist film material contains a metal oxide. The resist film material is also called "metal oxide photoresist." The metal oxide includes, for example, at least one of tin oxide, hafnium oxide, zinc oxide, and zirconium oxide.

[0044] For example, a resist film material contains a metal oxide complex. The metal oxide complex contains a metal oxide core and ligands. The metal oxide core is bound to the ligands. The metal oxide core is surrounded by the ligands. The ligands include at least one of an organic compound and / or a resin.

[0045] The resist film material contains a solvent. The solvent for the resist film material is, for example, an organic solvent. The solvent for the resist film material includes, for example, at least one of propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME).

[0046] The processing unit 14 will now be described. The processing unit 14 includes a hot plate 25. The hot plate 25 extends horizontally. The substrate W is placed on the hot plate 25. The hot plate 25 supports one substrate W in a horizontal position.

[0047] The processing unit 14 includes a heater 26. The heater 26 is attached to the hot plate 25. The heater 26 heats the substrate W on the hot plate 25.

[0048] Processing unit 15 will now be described. Processing unit 15 has a configuration similar to that of processing unit 14. Processing unit 15 includes a hot plate 28. The hot plate 28 extends horizontally. The substrate W is placed on the hot plate 28. The hot plate 28 supports one substrate W in a horizontal position.

[0049] The processing unit 15 includes a heater 29. The heater 29 is attached to the hot plate 28. The heater 29 heats the substrate W on the hot plate 28.

[0050] The processing unit 16 will now be described. The processing unit 16 includes a basic holding section 31. The substrate holding section 31 holds one substrate W in a substantially horizontal position.

[0051] The processing unit 16 includes a rotary drive unit 32. The rotary drive unit 32 is connected to the substrate holder 31. The rotary drive unit 32 rotates the substrate holder 31. The substrate W held by the substrate holder 31 rotates together with the substrate holder 31.

[0052] The processing unit 16 includes nozzles 33, 34, 35, and 36. Nozzle 33 supplies developer to the substrate W held by the substrate holding section 31. Nozzle 34 supplies displacement solution to the substrate W held by the substrate holding section 31. Nozzle 35 supplies processing solution to the substrate W held by the substrate holding section 31. Nozzle 36 supplies drying gas to the substrate W held by the substrate holding section 31.

[0053] The developer supplied by the nozzle 33 will be described. The developer is classified, for example, as a solvent developer.

[0054] The developer includes, for example, at least one of acetic acid, butyl acetate, 2-heptanone, and propylene glycol monomethyl ether acetate (PGMEA). The developer is, for example, a mixture of propylene glycol monomethyl ether acetate (PGMEA) and acetic acid.

[0055] The displacement fluid supplied by the nozzle 34 is described below. The displacement fluid includes, for example, an organic solvent. The displacement fluid includes, for example, an alcohol. The displacement fluid includes, for example, isopropyl alcohol (IPA).

[0056] The processing liquid supplied by the nozzle 35 is described below. The processing liquid contains a sublimable substance. The sublimable substance has sublimation properties. "Sublimation" refers to the property of an element, compound, or mixture to undergo a phase transition from solid to gas, or from gas to solid, without passing through a liquid phase.

[0057] The sublimable substance includes, for example, at least one of cyclohexanone oxime and camphor.

[0058] The processing solution contains a solvent. The solvent in the processing solution is, for example, a liquid. The solvent in the processing solution dissolves the sublimable substance. The sublimable substance in the processing solution is dissolved in the solvent. That is, the processing solution contains a solvent and a sublimable substance dissolved in the solvent. The sublimable substance corresponds to the solute in the processing solution.

[0059] The solvent in the processing solution is volatile. The solvent in the processing solution can, for example, change from a liquid to a gas. The solvent in the processing solution can evaporate from a liquid.

[0060] The solvent in the processing solution preferably has the same composition as the displacement solution.

[0061] The solvent in the processing solution includes, for example, an organic solvent. The solvent in the processing solution includes, for example, an alcohol. The solvent in the processing solution includes, for example, isopropyl alcohol (IPA).

[0062] The dry gas supplied by the nozzle 36 is described below. The dry gas is, for example, at least one of air and an inert gas. Air is, for example, compressed air. The inert gas is, for example, nitrogen gas. The dry gas preferably has a dew point lower than room temperature.

[0063] The processing unit 16 processes the substrate W under normal atmospheric pressure. The processing solution is used under normal atmospheric pressure.

[0064] Here, atmospheric pressure includes standard atmospheric pressure (1 atmosphere, 101325 Pa). Atmospheric pressure is, for example, a pressure between 0.7 atmospheres and 1.3 atmospheres. In this specification, pressure values ​​are expressed as absolute pressure relative to absolute vacuum.

[0065] The processing unit 16 processes the substrate W under normal temperature conditions. The processing solution is used under normal temperature conditions.

[0066] Here, room temperature includes ambient temperature. Room temperature is, for example, a temperature within the range of 5°C to 35°C. Room temperature is, for example, a temperature within the range of 10°C to 30°C. Room temperature is, for example, a temperature within the range of 20°C to 25°C.

[0067] The exposure machine 9 will now be described. The exposure machine 9 includes a stage 41. The stage 41 extends horizontally. A substrate W is placed on the stage 41. The stage 41 supports one substrate W in a horizontal position.

[0068] The exposure unit 9 is equipped with a photomask 42, also called a reticle. The photomask 42 is positioned above the stage 41. The photomask 42 has a pattern.

[0069] The exposure machine 9 is equipped with a light source 43. The light source 43 is positioned above the photomask 42. The light source 43 emits light. Only the light that passes through the photomask 42 reaches the substrate W on the stage 41. As a result, the pattern of the photomask 42 is transferred to the substrate W.

[0070] The light source 43 irradiates, for example, extreme ultraviolet light. In this specification, extreme ultraviolet light is appropriately abbreviated as "EUV light". EUV light has, for example, a wavelength of 13.5 nm.

[0071] <3. Substrate Processing Method> Refer to Figure 2-3. Figure 3 is a flowchart showing the procedure for the substrate processing method. The substrate processing method is for processing substrate W. The substrate processing method includes a resist film formation step, a second heating step, an exposure step, a first heating step, a development step, a replacement step, a processing solution supply step, a solidification film formation step, and a sublimation step.

[0072] <Step S1> Resist film formation process In the processing unit 13, a resist film is formed on the substrate W.

[0073] Specifically, the substrate holding unit 21 holds the substrate W. The rotation drive unit 22 rotates the substrate W. The nozzle 23 supplies the resist film material to the substrate W. The resist film material contains metal oxide.

[0074] Figure 4 is a schematic diagram showing a part of the substrate W during the resist film formation process. The resist film 51 is formed on the substrate W. The resist film 51 is made of a resist film material. For example, the resist film 51 is classified as a negative-type resist film. The resist film 51 contains metal oxide.

[0075] <Step S2> Second heating process After the resist film formation process, the second heating process is performed. In the processing unit 14, the substrate W is heated. For example, the substrate W is heated to a temperature between 100 and 150 degrees Celsius.

[0076] Specifically, the substrate W is placed on the hot plate 25. The heater 26 heats the substrate W on the hot plate 25.

[0077] In the second heating step, the solvent in the resist film 51 evaporates. The solvent content in the resist film 51 decreases.

[0078] <Step S3> Exposure process After the second heating step, the exposure step is performed. The substrate W is exposed in the exposure machine 9. That is, the resist film 51 on the substrate W is exposed.

[0079] Specifically, the substrate W is placed on the stage 41. The light source 43 irradiates light onto the substrate. The pattern of the photomask 42 is transferred to the resist film 51 on the substrate W.

[0080] For example, the light source 43 emits EUV light. The substrate W on the stage 41 is exposed to EUV light.

[0081] Figure 5 is a schematic diagram showing a part of the substrate W during the exposure process. Only light that has passed through the photomask 42 reaches the substrate W on the stage 41.

[0082] For example, before the exposure process, the resist film 51 is soluble in the developer. After the exposure process, the resist film 51 has an exposed portion 51a and an unexposed portion 51b. The exposed portion 51a is the part of the resist film 51 that has been exposed. The exposed portion 51a changes from soluble to insoluble. The unexposed portion 51b is the part of the resist film 51 that has not been exposed. The unexposed portion 51b remains soluble.

[0083] More specifically, the resist film 51 contains metal oxide. In the exposed area 51a, the bonds between the metal oxide cores and ligands are broken. The metal oxide cores and ligands separate from each other. Then, multiple metal oxide cores bond to each other. For example, multiple metal oxide cores condense together. As a result, the exposed area 51a changes from soluble to insoluble. In the unexposed area 51b, the bonds between the metal oxide cores and ligands are not broken. As a result, the unexposed area 51b remains soluble.

[0084] <Step S4> First heating process After the exposure process, the first heating process is performed. In the processing unit 15, the substrate W is heated. For example, the substrate W is heated to a temperature between 130°C and 250°C. For example, the substrate W is heated to a temperature between 180°C and 200°C.

[0085] Specifically, the substrate W is placed on the hot plate 28. The heater 29 heats the substrate W on the hot plate 28.

[0086] In the first heating step, the insolubility of the exposed portion 51a increases. The exposed portion 51a becomes even more insoluble in the developing solution.

[0087] <Step S5> Development Process After the first heating step, the developing step is performed. In the processing unit 16, the developing solution is supplied to the substrate W.

[0088] Specifically, the substrate holding unit 31 holds the substrate W. The rotation drive unit 32 rotates the substrate W. The nozzle 33 supplies developer to the substrate W.

[0089] Figure 6 is a schematic diagram showing a part of the substrate W during the development process. The resist film 51 is developed by the developer 53. Specifically, the unexposed areas 51b are removed from the substrate W by the developer 53. The exposed areas 51a remain on the substrate W.

[0090] In the development process, a resist pattern 52 is formed on the substrate W. The resist pattern 52 includes protrusions 52a and recesses 52b. The protrusions 52a consist of exposed areas 51a. The recesses 52b are empty spaces. The recesses 52b are located in the same position as the unexposed areas 51b. The recesses 52b are formed to the side of the protrusions 52a.

[0091] The resist pattern 52 contains metal oxide. The protrusions 52a contain metal oxide.

[0092] <Step S6> Replacement process After the development process, a replacement process is performed. In the processing unit 16, the replacement solution is supplied to the substrate W.

[0093] Specifically, the substrate holding unit 31 holds the substrate W. The rotation drive unit 32 rotates the substrate W. The nozzle 34 supplies a displacement solution to the substrate W. The displacement solution has the same composition as the solvent of the processing solution, for example. The displacement solution contains isopropyl alcohol, for example.

[0094] Figure 7 is a schematic diagram showing a portion of the substrate W during the replacement process. The developer 53 on the substrate W is replaced with the replacement solution 54. The developer 53 is removed from the substrate W.

[0095] <Step S7> Processing liquid supply process After the replacement process, the processing liquid supply process is performed. In the processing unit 16, the processing liquid is supplied to the substrate W.

[0096] Specifically, in the processing unit 16, the substrate holding unit 31 holds the substrate W. The rotation drive unit 32 rotates the substrate W. The nozzle 35 supplies processing liquid to the substrate W. The processing liquid contains a sublimable substance and a solvent. The sublimable substance includes, for example, at least one of cyclohexanone oxime and camphor. The solvent of the processing liquid contains isopropyl alcohol.

[0097] Figure 8 is a schematic diagram showing a part of the substrate W during the processing liquid supply process. The processing liquid 55 is supplied to the substrate W having a resist pattern 52. The replacement liquid 54 on the substrate W is replaced by the processing liquid 55. The replacement liquid 54 is removed from the substrate W.

[0098] The processing liquid 55 on the substrate W is called the "liquid film 56". In the processing liquid supply process, the liquid film 56 is formed. In the processing liquid supply process, the liquid film 56 covers the substrate W. In the processing liquid supply process, the liquid film 56 covers the resist pattern 52.

[0099] In the processing liquid supply step, the entire resist pattern 52 is immersed in the liquid film 56. The protrusions 52a are immersed in the liquid film 56. The recesses 52b are filled with the liquid film 56.

[0100] The liquid film 56 is in contact with the gas G. Specifically, the liquid film 56 has an upper surface 56a. The upper surface 56a is in contact with the gas G. The upper surface 56a corresponds to the gas-liquid interface between the liquid film 56 and the gas G.

[0101] In the processing liquid supply process, the upper surface 56a is positioned higher than the resist pattern 52. The resist pattern 52 does not intersect with the upper surface 56a. The resist pattern 52 does not intersect with the gas-liquid interface between the liquid film 56 and the gas G. Therefore, the resist pattern 52 is not affected by the surface tension of the liquid film 56.

[0102] In the processing liquid supply process, the upper surface 56a is located higher than the protrusion 52a. The protrusion 52a does not intersect with the upper surface 56a. The protrusion 52a does not intersect with the gas-liquid interface between the liquid film 56 and the gas G. Therefore, the protrusion 52a is not subjected to the surface tension of the liquid film 56.

[0103] <Step S8> Solidification film formation process After the processing liquid supply step, the solidification film formation step is performed. In the processing unit 16, the solvent of the processing liquid 56 evaporates from the processing liquid 55 on the substrate W. A solidification film is formed on the substrate W. The solidification film contains a sublimable substance.

[0104] Specifically, the substrate holding unit 31 holds the substrate W. The rotation drive unit 32 rotates the substrate W.

[0105] Figure 9 is a schematic diagram showing a part of the substrate W during the solidification film formation process. As described above, the solvent in the processing liquid 55 is volatile. Therefore, during the solidification film formation process, the solvent in the liquid film 56 evaporates smoothly.

[0106] Eventually, the sublimable substance in the liquid film 56 begins to precipitate on the substrate W. That is, the sublimable substance changes from a solute in the processing liquid 55 to a solid-phase sublimable substance. The solid-phase sublimable substance forms a solidified film 57. Due to the precipitation of the sublimable substance, the liquid film 56 gradually changes into a solidified film 57.

[0107] The solidified film 57 does not contain a solvent. The solidified film 57 is a solid. The solidified film 57 is formed on the substrate W.

[0108] For example, the upper part of the liquid film 56 may be transformed into the solidified film 57 first. For example, the upper part of the liquid film 56 may be transformed into the solidified film 57 before the lower part of the liquid film 56 is transformed into the solidified film 57. In this case, the solidified film 57 is located above the liquid film 56. The solidified film 57 covers the upper surface 56a of the liquid film 56.

[0109] When the solidified film 57 covers the entire upper surface 56a, the solidified film 57 separates the liquid film 56 from the gas G. The liquid film 56 does not come into contact with the gas G. The upper surface 56a no longer corresponds to a gas-liquid interface. The gas-liquid interface between the liquid film 56 and the gas G disappears.

[0110] After the gas-liquid interface between the liquid film 56 and the gas G disappears, the resist pattern 52 is no longer subjected to the surface tension of the liquid film 56. After the gas-liquid interface between the liquid film 56 and the gas G disappears, the protrusions 52a are no longer subjected to the surface tension of the liquid film 56.

[0111] For example, the upper surface 56a is lowered to the same height as the resist pattern 52. For example, the upper surface 56a is lowered to the same height as the protrusion 52a. In this case, the upper surface 56a intersects with the resist pattern 52. The upper surface 56a intersects with the protrusion 52a.

[0112] As described above, the upper surface 56a no longer corresponds to a gas-liquid interface. Therefore, even when the upper surface 56a intersects with the resist pattern 52, the resist pattern 52 is not subjected to the surface tension of the liquid film 56. Even when the upper surface 56a intersects with the convex portion 52a, the convex portion 52a is not subjected to the surface tension of the liquid film 56. Thus, the liquid film 56 decreases without the liquid film 56 acting a significant force on the resist pattern 52. The liquid film 56 decreases without the liquid film 56 acting a significant force on the convex portion 52a.

[0113] Figure 10 is a schematic diagram showing a part of the substrate W during the solidification film formation process. Figure 10 schematically shows, for example, the substrate W at the end of the solidification film formation process. At the end of the solidification film formation process, the entire liquid film 56 disappears from the substrate W. At the end of the solidification film formation process, no liquid film 56 remains on the substrate W.

[0114] At the end of the solidification film formation process, only the solidified film 57 is present on the substrate W. The recess 52b is filled with the solidified film 57. The solidified film 57 is in contact with the resist pattern 52. The solidified film 57 supports the resist pattern 52. The solidified film 57 protects the resist pattern 52. For example, the solidified film 57 prevents the resist pattern 52 from collapsing.

[0115] The solidified film 57 is in contact with the protrusion 52a. The solidified film 57 supports the protrusion 52a. The solidified film 57 protects the protrusion 52a. For example, the solidified film 57 prevents the protrusion 52a from collapsing.

[0116] <Step S9> Sublimation Process After the solidification film formation process, the sublimation process is carried out. In the processing unit 16, the solidified film 57 on the substrate W is sublimated.

[0117] Specifically, the substrate holding unit 31 holds the substrate W. The rotation drive unit 32 rotates the substrate W. The nozzle 36 supplies drying gas to the substrate W.

[0118] The drying gas promotes the sublimation of the solidified film 57. The solidified film 57 changes into a gas without passing through a liquid state. Through sublimation, the solidified film 57 is removed from the substrate W.

[0119] Figure 11 is a schematic diagram showing a portion of the substrate W during the sublimation process. As the solidified film 57 sublimes, the solidified film 57 gradually decreases. The resist pattern 52 begins to be exposed to the gas G. The protrusions 52a begin to be exposed to the gas G.

[0120] When the solidified film 57 sublimes, it does not exert any significant force on the resist pattern 52. Without exerting any significant force on the resist pattern 52, the solidified film 57 leaves the substrate W.

[0121] When the solidified film 57 sublimes, it does not exert any significant force on the protrusions 52a. Without exerting any significant force on the protrusions 52a, the solidified film 57 leaves the substrate W.

[0122] When the solidified film 57 sublimes, the solidified film 57 does not change into a liquid. Therefore, no liquid is generated on the substrate W during the sublimation process. Consequently, no gas-liquid interface is generated near the resist pattern 52 during the sublimation process. No gas-liquid interface is generated near the protrusions 52a during the sublimation process. Consequently, the resist pattern 52 does not intersect with the gas-liquid interface during the sublimation process. No protrusions 52a intersect with the gas-liquid interface during the sublimation process. Consequently, the resist pattern 52 is not subjected to the surface tension of the liquid during the sublimation process. No protrusions 52a are subjected to the surface tension of the liquid during the sublimation process.

[0123] Figure 12 is a schematic diagram showing a part of the substrate W during the sublimation process. Figure 12 schematically shows, for example, the substrate W at the end of the sublimation process. At the end of the sublimation process, the entire solidified film 57 disappears from the substrate W. At the end of the sublimation process, no solidified film 57 remains on the substrate W. At the end of the sublimation process, no liquid is present on the substrate W. The substrate W is dried. Specifically, the entire resist pattern 52 is exposed to the gas G. The entire protrusion 52a is exposed to the gas G. The entire recess 52b is filled only with the gas G.

[0124] Here, the resist pattern 52 includes, for example, at least one of lines, spaces, dots, pillars, and holes. For example, the resist pattern 52 may be classified as a line and space pattern.

[0125] The resist pattern 52 has a critical dimension CD. The critical dimension CD is, for example, the width of a line included in the resist pattern 52. The critical dimension CD is, for example, the diameter width of a dot included in the resist pattern 52. The critical dimension CD is, for example, the diameter width of a pillar included in the resist pattern 52.

[0126] As stated above, the processing solution 55 is used under normal temperature conditions. The processing solution 55 is used under normal pressure conditions.

[0127] <4. Technical significance of substrate processing methods> The technical significance of the substrate processing method of the embodiment will be explained by examples and comparative examples.

[0128] The conditions of the embodiment are described below. In the embodiment, a series of processes shown in Figure 3 are performed on the substrate W. Specifically, the series of processes in the embodiment include a resist film formation step, a second heating step, an exposure step, a first heating step, a developing step, a replacement step, a processing solution supply step, a solidification film formation step, and a sublimation step. In the resist film formation step, a resist film 51 is formed on the substrate W. The resist film 51 is classified as a negative-type resist film. The resist film 51 contains metal oxide. In the exposure step, the substrate W is exposed to EUV light. As a result of the series of processes performed on the substrate W, a substrate W having a resist pattern 52 is obtained. The resist pattern 52 is classified as a line and space pattern.

[0129] In the exposure process, multiple substrates W were exposed with different light intensities. As a result, in this example, multiple substrates W with different critical dimensions CD were obtained. The critical dimension CD is the width of the lines included in the resist pattern 52.

[0130] Generally, when the resist film 51 is classified as a negative-type resist film, the critical dimension CD increases as the light intensity increases.

[0131] The conditions for the comparative example are described below. In the comparative example, a series of processes are performed on the substrate W. The series of processes in the comparative example include a spin-drying step instead of the substitution step, processing solution supply step, solidification film formation step, and sublimation step. Specifically, the series of processes in the comparative example include a resist film formation step, a second heating step, an exposure step, a first heating step, a development step, and a spin-drying step. All other conditions are the same for the comparative example as for the example.

[0132] Each substrate W processed in the examples and comparative examples was evaluated by its defect rate E. The defect rate E is the number of defects per unit length of lines in the resist pattern 52. The unit length is 1 mm.

[0133] Figure 13 is a graph showing the evaluation of substrates processed in the example and substrates processed in the comparative example. The horizontal axis represents the critical dimension CD. The vertical axis represents the defect rate E. The defect rate E of the example is lower than that of the comparative example. More specifically, when the critical dimension CD is small, the defect rate E of the example is significantly lower than that of the comparative example. In the range of critical dimension CD between 12 nm and 18 nm, the defect rate E of the example is significantly lower than that of the comparative example.

[0134] The following can be observed from Figure 13: The number of defects in the resist pattern 52 in the example is lower than that in the comparative example. The example suppresses the collapse of the resist pattern 52 better than the comparative example. In the example, the resist pattern 52 is suitably protected compared to the comparative example. In the example, the substrate W is dried while the resist pattern 52 is suitably protected.

[0135] <5. Effects of the Embodiment> The substrate processing method of this embodiment is for processing a substrate. The substrate processing method comprises a developing step, a processing solution supply step, a solidification film formation step, and a sublimation step. In the developing step, a developing solution 53 is supplied to the substrate W. In the processing solution supply step, a processing solution 55 is supplied to the substrate W. The processing solution 55 contains a sublimable substance and a solvent. In the solidification film formation step, the solvent evaporates from the processing solution 55 on the substrate W. In the solidification film formation step, a solidification film 57 is formed on the substrate W. The solidification film 57 contains a sublimable substance. In the sublimation step, the solidification film 57 sublimes. The substrate W is dried by the sublimation of the solidification film 57.

[0136] As described above, the substrate processing method includes a developing step. Therefore, the substrate W can be properly processed according to the substrate processing method. Specifically, according to the substrate processing method, the developing solution 53 is supplied to the substrate W, and then the substrate W is properly dried.

[0137] The processing solution supply process is performed after the developing process. The solidification film formation process is performed after the processing solution supply process. The sublimation process is performed after the solidification film formation process. Therefore, the substrate processing method can properly process the substrate W.

[0138] In the development process, a resist pattern 52 is formed on the substrate W. Therefore, in the processing solution supply process, the solidification film formation process, and the sublimation process, the substrate W has the resist pattern 52. In the processing solution supply process, a processing solution 55 is supplied to the substrate W having the resist pattern 52. Even when the substrate W has the resist pattern 52, the substrate W is properly processed in the processing solution supply process, the solidification film formation process, and the sublimation process. For example, in the processing solution supply process, the solidification film formation process, and the sublimation process, the substrate W is dried while the resist pattern 52 is suitably protected. Rather, when the resist pattern 52 is formed on the substrate W in the development process, the substrate processing method exhibits a remarkable effect.

[0139] The resist pattern 52 contains metal oxide. Therefore, the substrate W is treated more appropriately in the processing liquid supply step, the solidification film formation step, and the sublimation step. For example, the substrate W is dried while the resist pattern 52 is more favorably protected in the processing liquid supply step, the solidification film formation step, and the sublimation step.

[0140] The sublimable substance contains at least one of cyclohexanone oxime and camphor. Therefore, the substrate W is properly treated in the processing liquid supply step, the solidification film formation step, and the sublimation step. For example, the substrate W is properly dried in the processing liquid supply step, the solidification film formation step, and the sublimation step.

[0141] The solvent in the processing solution 55 contains isopropyl alcohol. Therefore, the substrate W is properly processed in the processing solution supply step, the solidification film formation step, and the sublimation step. For example, the substrate W is properly dried in the processing solution supply step, the solidification film formation step, and the sublimation step.

[0142] The substrate processing method includes a replacement step in which a replacement solution 54 is supplied to the substrate W. The replacement step is performed after the development step. The replacement step is performed before the processing solution supply step. Therefore, in the replacement step, the developer solution 53 on the substrate W is replaced with the replacement solution 54. In other words, in the replacement step, the developer solution 53 is removed from the substrate W. Thus, in the processing solution supply step, the processing solution 55 is appropriately supplied to the substrate W.

[0143] As described above, the substrate processing method includes a replacement step. Therefore, after the developer 53 is removed from the substrate W, the processing solution 55 is supplied to the substrate W. Thus, the processing solution 55 does not come into contact with the developer 53. Consequently, the processing solution 55 does not react with the developer 53. Therefore, in the processing solution supply step, the processing solution 55 is appropriately supplied to the substrate W.

[0144] The displacement solution 54 has the same composition as the solvent in the processing solution 55. Therefore, the displacement solution 54 has a high affinity for the processing solution 55. Thus, the processing solution 55 is supplied to the substrate W more appropriately during the processing solution supply process. For example, it is easy to reduce the consumption of the processing solution 55.

[0145] The substrate processing method includes an exposure step in which the substrate W is exposed to light. The exposure step is performed before the development step. Even if the substrate W is exposed during the exposure step, the substrate W is processed appropriately. In fact, when the substrate processing method includes an exposure step, the substrate processing method exhibits significant effects.

[0146] During the exposure process, the substrate W is exposed to extreme ultraviolet light. Therefore, the substrate W is treated more effectively.

[0147] In the exposure process, a pattern is transferred to the resist film 51 on the substrate W. Therefore, it is easy to form the resist pattern 52 on the substrate W in the development process. As described above, even when the resist pattern 52 is formed on the substrate W in the development process, the substrate W is properly processed in the processing solution supply process, the solidification film formation process, and the sublimation process.

[0148] The substrate processing method includes a first heating step of heating the substrate. The first heating step is performed after the exposure step. The first heating step is performed before the development step. Therefore, the substrate W is properly developed in the development step. For example, after the exposure step, the substrate W has an exposed area 51a. The exposed area 51a is the portion of the substrate W that was exposed in the exposure step. The first heating step increases the insolubility of the exposed area 51a to the developer, for example. Therefore, the exposed area 51a remains properly on the substrate W in the development step.

[0149] The substrate processing method includes a resist film formation step in which a resist film 51 is formed on a substrate W. The resist film formation step is performed before the exposure step. Even if a resist film 51 is formed on the substrate W in the resist film formation step, the substrate W is processed appropriately. Rather, when the substrate processing method includes a resist film formation step, the substrate processing method exhibits significant effects.

[0150] The resist film 51 contains metal oxide. Therefore, the substrate W is treated more effectively. For example, in the treatment solution supply step, the solidification film formation step, and the sublimation step, the substrate W is dried more effectively.

[0151] The substrate processing method includes a second heating step for heating the substrate. The second heating step is performed after the resist film formation step. The second heating step is performed before the exposure step. Therefore, the substrate W is processed more appropriately in the exposure step and the development step. For example, the second heating step evaporates the solvent in the resist film 51. As a result, the resist film 51 is properly formed on the substrate W. In other words, the resist film 51 is properly modified. Therefore, in the exposure step, the resist film 51 on the substrate W is properly exposed. In the development step, the resist film 51 on the substrate W is properly developed.

[0152] <6. Modified Embodiments> The present invention is not limited to the embodiments described below and can be modified and implemented as follows.

[0153] (1) In the substrate processing method of the embodiment, the steps performed before the development step may be appropriately changed. For example, at least one of the resist film formation step, the second heating step, the exposure step, and the first heating step may be omitted.

[0154] (2) In the substrate processing method of the embodiment, the steps performed after the development step may be changed as appropriate. For example, the substitution step may be omitted.

[0155] (3) In the solidification film formation process, the drying gas does not need to be supplied to the substrate W.

[0156] Alternatively, a drying gas may be supplied to the substrate W during the solidification film formation process. During the solidification film formation process, a drying gas may be supplied to the processing liquid 55 on the substrate W. During the solidification film formation process, a drying gas may be supplied to the liquid film 56. According to this modified embodiment, during the solidification film formation process, the processing liquid 55 on the substrate W is exposed to the drying gas. Therefore, during the solidification film formation process, the solvent in the processing liquid 55 evaporates efficiently. During the solidification film formation process, the solidified film 57 is efficiently formed on the substrate W.

[0157] (4) The embodiments and each modified embodiment described in (1) to (3) above may be further modified as appropriate by substituting or combining each component with the components of other modified embodiments. [Explanation of Symbols]

[0158] 1 ... Substrate processing equipment 5… Processing section 9… Exposure machine 13… Processing unit (processing unit for the resist film formation process) 14… Processing unit (Processing unit for the second heating process) 15… Processing unit (Processing unit for the first heating process) 16… Processing unit (processing unit for developing, replacement, processing solution supply, solidification film formation, and sublimation processes) 51 … Resist film 51a… Exposure area 51b… Unexposed area 52 … Resist Pattern 52a… protruding part 52b… recess 53… Developer 54 … Substitution liquid 55... Processing liquid 56 … liquid film 57... Solidification film CD… Critical Dimension E... Defect rate W… Circuit board

Claims

1. A substrate processing method for processing a substrate, The developing process involves supplying a developer solution to the substrate, A processing liquid supply step involves supplying a processing liquid containing a sublimable substance and a solvent to a substrate, A solidification film formation step involves evaporating the solvent from the processing liquid on the substrate to form a solidified film containing the sublimable substance on the substrate, A sublimation step for sublimating the solidified film, Equipped with Substrate processing method.

2. In the substrate processing method described in claim 1, In the development process, a resist pattern is formed on the substrate. Substrate processing method.

3. In the substrate processing method described in claim 2, The resist pattern includes metal oxide Substrate processing method.

4. In the substrate processing method described in claim 1, The sublimable substance comprises at least one of cyclohexanone oxime and camphor. Substrate processing method.

5. In the substrate processing method described in claim 1, The solvent comprises isopropyl alcohol. Substrate processing method.

6. In the substrate processing method described in claim 1, The process includes a replacement step, which involves supplying a replacement solution to the substrate after the developing step and before the processing solution supply step. Substrate processing method.

7. In the substrate processing method described in claim 6, The displacement solution has the same composition as the solvent. Substrate processing method.

8. In the substrate processing method described in claim 1, The development step is preceded by an exposure step in which the substrate is exposed. Substrate processing method.

9. In the substrate processing method described in claim 8, In the exposure process described above, the substrate is exposed to extreme ultraviolet light. Substrate processing method.

10. In the substrate processing method described in claim 8, In the exposure process, a pattern is transferred to the resist film on the substrate. Substrate processing method.

11. In the substrate processing method described in claim 8, The process includes a first heating step, which heats the substrate after the exposure step and before the development step. Substrate processing method.

12. In the substrate processing method described in claim 8, Prior to the exposure step, the process includes a resist film formation step in which a resist film is formed on the substrate. Substrate processing method.

13. In the substrate processing method according to claim 12, The resist film contains metal oxide Substrate processing method.

14. In the substrate processing method according to claim 12, The process includes a second heating step, which heats the substrate after the resist film formation step and before the exposure step. Substrate processing method.

Images