Substrate processing method, storage medium, and substrate processing apparatus

Abstract

To provide a substrate processing method and a substrate processing device that are effective in suppressing pattern collapse of uneven patterns.SOLUTION: The substrate processing method includes replacing a liquid in a recess of a substrate on which an uneven surface pattern is formed with a reinforcement material in a solid state and applying a low molecular weight processing to the substrate to reduce the number of bonds between molecules in the reinforcement material while maintaining the reinforcement material in a solid state.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a substrate processing method and a substrate processing apparatus. [Background technology]

[0002] Patent Document 1 discloses a substrate drying method (substrate processing method) for removing a liquid on a substrate having a concave-convex pattern formed on its surface, and drying the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-243869 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a substrate processing method and a substrate processing apparatus that are effective in suppressing collapse of a concave-convex pattern. [Means for solving the problem]

[0005] A substrate processing method according to one aspect of the present disclosure includes replacing a liquid in a recess of a substrate having a textured pattern formed on its surface with a solid-state reinforcing material, and subjecting the substrate to a low-molecular-weight treatment that reduces the number of bonds between molecules contained in the reinforcing material while maintaining the reinforcing material in a solid state. [Effects of the Invention]

[0006] According to the present disclosure, a substrate processing method and a substrate processing apparatus are provided that are effective in suppressing collapse of a concave-convex pattern. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating the general configuration of a substrate processing system. [Figure 2]FIG. 2 is a schematic view illustrating the internal configuration of the coating and developing apparatus. [Figure 3] FIG. 3 is a schematic diagram illustrating the configuration of the development unit. [Figure 4] FIG. 4 is a schematic diagram illustrating the configuration of the irradiation unit. [Figure 5] FIG. 5 is a schematic diagram illustrating the configuration of a plasma processing apparatus. [Figure 6] FIG. 6 is a block diagram illustrating the functional configuration of the control device. [Figure 7] FIG. 7 is a block diagram illustrating a hardware configuration of the control device. [Figure 8] FIG. 8 is a flowchart showing an example of a development processing procedure. [Figure 9] 9(a) to 9(d) are schematic diagrams for explaining the state inside the recess in an example of the development processing procedure. [Figure 10] FIG. 10 is a diagram showing an example of the chemical formula of the polymer contained in the reinforcing material. [Figure 11] Fig. 11(a) is a schematic diagram illustrating an exposure process in an example of the exposure process, and Fig. 11(b) is a schematic diagram illustrating an example of a development process procedure according to a modified example. [Figure 12] 12(a) and 12(b) are schematic diagrams for explaining an example of a development processing procedure. [Figure 13] FIG. 13 is a schematic diagram for explaining an example of a development processing procedure. [Figure 14] FIG. 14 is a schematic diagram for explaining another example of the procedure of the development process according to the modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Various exemplary embodiments will be described below. In the description, the same elements or elements having the same functions are denoted by the same reference numerals, and redundant description will be omitted.

[0009] [Substrate processing system] First, a schematic configuration of a substrate processing system 1 (substrate processing apparatus) will be described with reference to FIGS. 1 and 2. The substrate processing system 1 is a system that forms a photosensitive coating on a substrate, exposes the photosensitive coating, and develops the photosensitive coating. The substrate to be processed is, for example, a semiconductor wafer W. The photosensitive coating is, for example, a resist film. The substrate processing system 1 includes a coating / developing apparatus 2, an exposure apparatus 3, a plasma processing apparatus 10, and a control apparatus 100. The exposure apparatus 3 exposes a resist film (photosensitive coating) formed on a wafer W (substrate). Specifically, the exposure apparatus 3 irradiates an exposure target portion of the resist film with an energy beam for exposure by a method such as immersion exposure. The coating / developing apparatus 2 applies a resist (chemical solution) to the surface of the wafer W (substrate) to form a resist film before the exposure process by the exposure apparatus 3. The coating / developing apparatus 2 also performs a development process of the resist film after the exposure process. After the development process of the resist film, the plasma processing apparatus 10 performs an etching process using plasma on the surface Wa (see FIG. 3) of the wafer W. For example, the plasma processing apparatus 10 performs the etching process of the wafer W using a resist pattern formed by the development process of the resist film as a mask.

[0010] (Coating and developing equipment) As shown in FIGS. 1 and 2, the coating and developing apparatus 2 (substrate processing apparatus) includes a carrier block 4, a processing block 5, and an interface block 6.

[0011] The carrier block 4 introduces wafers W into the coating and developing apparatus 2 and removes wafers W from the coating and developing apparatus 2. For example, the carrier block 4 can support a plurality of carriers C for wafers W and has a built-in transfer device A1 including a transfer arm. The carrier C accommodates, for example, a plurality of circular wafers W. The transfer device A1 removes wafers W from the carrier C and transfers them to the processing block 5, and receives wafers W from the processing block 5 and returns them to the carrier C. The processing block 5 has a plurality of processing modules 11, 12, 13, and 14.

[0012] The processing module 11 incorporates a coating unit U1, a heat-processing unit U2, and a transfer device A3 that transfers the wafer W to these units. The processing module 11 forms an underlayer film on the surface of the wafer W using the coating unit U1 and the heat-processing unit U2. The coating unit U1 applies a processing liquid for forming the underlayer film onto the wafer W. The heat-processing unit U2 performs various heat treatments associated with the formation of the underlayer film.

[0013] The processing module 12 incorporates a coating unit U1, a heat-treating unit U2, and a transfer device A3 that transfers the wafer W to these units. The processing module 12 forms a resist film on the underlying film using the coating unit U1 and the heat-treating unit U2. The coating unit U1 applies resist onto the underlying film as a processing liquid for forming the resist film. The heat-treating unit U2 performs various heat treatments associated with the formation of the resist film. As a result, a resist film is formed on the surface of the wafer W.

[0014] The processing module 13 incorporates a coating unit U1, a heat-treating unit U2, and a transfer device A3 that transfers the wafer W to these units. The processing module 13 forms an upper layer film on the resist film using the coating unit U1 and the heat-treating unit U2. The coating unit U1 applies a processing liquid for forming the upper layer film onto the resist film. The heat-treating unit U2 performs various heat treatments associated with the formation of the upper layer film.

[0015] The processing module 14 incorporates a developing unit U3, a thermal processing unit U4, an irradiation unit U5, and a transfer device A3 that transfers the wafer W to these units. The processing module 14 performs a series of processes, including a development process for the exposed resist film, using the developing unit U3, the thermal processing unit U4, and the irradiation unit U5. The developing unit U3 applies (supplies) a developer to the surface of the exposed wafer W to partially remove the resist film (performs a development process). In other words, the developing unit U3 forms a resist pattern, which is a concave-convex pattern, on the surface of the wafer W. The developing unit U3 supplies a rinse liquid to the surface of the wafer W to wash away the developer. The developing unit U3 also replaces the rinse liquid in recesses of the resist pattern with a processing liquid, and then forms a reinforcing material in the recesses (see FIG. 9(b)). The thermal processing unit U4 performs various heat treatments associated with the development process. Specific examples of heat treatments associated with the development process include a heat treatment before the development process (PEB: Post Exposure Bake), a heat treatment after the development process (PB: Post Bake), etc. The irradiation unit U5 has a function of irradiating the surface of the wafer W with energy rays, and performs part of the process for removing the rinse liquid.

[0016] A shelf unit U10 is provided on the carrier block 4 side within the processing block 5. The shelf unit U10 is divided into multiple cells arranged in the vertical direction. A transfer device A7 including a lifting arm is provided near the shelf unit U10. The transfer device A7 raises and lowers wafers W between the cells of the shelf unit U10.

[0017] A shelf unit U11 is provided on the interface block 6 side in the processing block 5. The shelf unit U11 is divided into a plurality of cells arranged in the vertical direction.

[0018] The interface block 6 transfers wafers W to and from the exposure apparatus 3. For example, the interface block 6 has a built-in transfer device A8 including a transfer arm, and is connected to the exposure apparatus 3. The transfer device A8 transfers wafers W placed on the shelf unit U11 to the exposure apparatus 3. The transfer device A8 receives wafers W from the exposure apparatus 3 and returns them to the shelf unit U11.

[0019] (developing unit) Next, an example of the developing unit U3 will be described with reference to Fig. 3. As shown in Fig. 3, the developing unit U3 includes a rotation holder 20 and liquid supply units 30a, 30b, and 30c (three liquid supply units).

[0020] The rotary holder 20 includes a rotary drive unit 21, a shaft 22, and a holder 23. The rotary drive unit 21 operates based on an operation signal from the control device 100 to rotate the shaft 22. The rotary drive unit 21 incorporates a power source such as an electric motor. The holder 23 is provided at the tip of the shaft 22. The wafer W is placed on the holder 23. The holder 23 holds the wafer W approximately horizontally, for example, by suction. In this case, the rotary holder 20 rotates the wafer W around a central axis (rotation axis) perpendicular to the surface Wa of the wafer W while the wafer W is positioned approximately horizontally. In the example of FIG. 3, the rotary holder 20 rotates the wafer W counterclockwise when viewed from above at a predetermined rotation speed.

[0021] The liquid supply unit 30a supplies a developer L1 to the surface Wa of the wafer W. The developer L1 is a chemical liquid for performing a development process on the resist film R to form a resist pattern. For example, when the developer L1 is supplied to the resist film R, portions of the resist film R that are irradiated with the exposure energy beam (areas exposed in the exposure process) react with each other and are removed. That is, a negative resist pattern (resist material) may be used. An example of the developer L1 that removes the exposed areas is an organic solvent. Note that when the developer L1 is supplied to the resist film R, portions of the resist film R that are not irradiated with the exposure energy beam (areas not exposed in the exposure process) may react with each other and be removed. That is, a positive resist pattern (resist material) may be used. An example of the developer L1 that removes the unexposed areas is an alkaline solution.

[0022] The liquid supply unit 30b supplies a rinse liquid L2 to the surface Wa of the wafer W (the resist film R on which the resist pattern is formed). The rinse liquid L2 may be any chemical liquid (liquid) that can wash away the developer L1. For example, the rinse liquid L2 may be water (pure water). The liquid supply unit 30a and the liquid supply unit 30b constitute a development processing unit that performs development processing on the resist film R.

[0023] The liquid supply unit 30c (replacement processing unit) supplies a processing liquid L3 to the surface Wa of the wafer W. The processing liquid L3 is a chemical liquid for forming a reinforcing material in the recesses of the resist pattern. The processing liquid L3 can be supplied to the wafer W in a liquid state and may be a chemical liquid that dries and solidifies by a predetermined process (e.g., rotation of the wafer W). For example, the processing liquid L3 may be a chemical liquid in which a polymer is dissolved in a solvent. The polymer may contain at least one of polymethyl acrylate, polymethacrylic acid, polyvinyl alcohol, ultraviolet curable resin (UV curable resin), and polymethylmethacrylate (PMMA). When polymethyl acrylate, polymethacrylic acid, or polyvinyl alcohol is used, water may be used as the solvent. When polymethyl methacrylate is used, acetone, isopropyl alcohol (IPA), methyl alcohol, ethyl alcohol, xylene, acetic acid, methyl isobutyl ketone (MIBK), methyl isobutyl carbinol (MIBC), butyl acetate, or propylene glycol methyl ether acetate (PGMEA) may be used as the solvent.

[0024] Each of the liquid supply units 30a, 30b, and 30c includes a liquid source 31, a valve 33, a nozzle 34, and a pipe 35. The liquid source 31 of each of the liquid supply units 30a, 30b, and 30c supplies a chemical liquid to the nozzle 34 via the valve 33 and the pipe 35. The nozzle 34 of each of the liquid supply units 30a, 30b, and 30c is disposed above the wafer W such that the outlet faces the front surface Wa of the wafer W. The nozzle 34 discharges the chemical liquid supplied from the liquid source 31 toward the front surface Wa of the wafer W. The pipe 35 connects the liquid source 31 and the nozzle 34. The valve 33 switches the flow path in the pipe 35 between an open state and a closed state. The developing unit U3 may include a drive mechanism (not shown) that moves the nozzle 34 back and forth horizontally.

[0025] Although a detailed configuration diagram is omitted, the thermal processing unit U4 has a configuration capable of performing thermal processing on the wafer W. For example, the thermal processing unit U4 includes an openable chamber that forms a processing space in which the thermal processing is performed, and a hot plate housed in the chamber that supports and heats the wafer W. The chamber opens and closes in response to instructions from the control device 100. The hot plate has, for example, a built-in heater, and the temperature of the hot plate is controlled by the control device 100.

[0026] (Irradiation unit) Next, an example of the irradiation unit U5 will be described with reference to Fig. 4. As shown in Fig. 4, the irradiation unit U5 includes an irradiation section 42 (depolymerization processing section).

[0027] The irradiation unit 42 irradiates the surface Wa (reinforcing material) of the wafer W with energy rays. The energy rays may be, for example, particle rays such as electron beams, or electromagnetic waves. The irradiation unit 42 may irradiate any energy rays as long as the number of intermolecular bonds contained in the reinforcing material can be reduced by the irradiation. For example, the irradiation unit 42 may irradiate energy rays that can reduce the degree of polymerization of the polymer contained in the reinforcing material. A specific example of the energy rays is ultraviolet light with a wavelength of 100 nm to 400 nm. The wavelength of the energy rays may be 170 nm to 180 nm. Note that the wavelength of the energy rays is not limited to the above values, and the wavelength of the energy rays to be used may be selected depending on, for example, the type of reinforcing material.

[0028] The irradiation unit U5 emits ultraviolet light from above onto the surface Wa of the horizontally supported wafer W using an irradiation section 42. For example, the irradiation section 42 has a light source that emits ultraviolet light. Specific examples of the light source include a krypton fluoride excimer light source that emits ultraviolet light with a wavelength of 172 nm, an argon fluoride excimer light source that emits ultraviolet light with a wavelength of 193 nm, and a krypton chloride excimer light source that emits ultraviolet light with a wavelength of 222 nm. The irradiation section 42 is configured to emit the energy beam emitted from the light source downward toward the wafer W.

[0029] (Plasma processing equipment) Next, an example of a plasma processing apparatus 10 will be described with reference to FIG. 5. The plasma processing apparatus 10 performs plasma processing on the wafer W using a resist pattern as a mask. In other words, the plasma processing apparatus 10 performs an etching process using plasma on the wafer W, thereby etching a portion of the wafer W. The plasma processing apparatus 10 may also perform an etching process using plasma on a reinforcing material formed in a recess of the resist pattern. Note that, in this specification, "performing plasma processing" or "performing an etching process using plasma" refers to exposing at least the surface Wa of the wafer W to a gas in a plasma state for a predetermined period of time.

[0030] The plasma processing apparatus 10 is connected to the coating and developing apparatus 2 via a transfer mechanism 19 (see FIG. 2). The transfer mechanism 19 transfers the wafer W between the coating and developing apparatus 2 and the plasma processing apparatus 10. The plasma processing apparatus 10 is, for example, a parallel plate type apparatus. As shown in FIG. 5, the plasma processing apparatus 10 includes a processing section 60, a power supply section 80, and an exhaust section 90. The processing section 60 includes a processing vessel 68, an electrostatic chuck 61, a susceptor 63, a support table 64, and an upper electrode 73.

[0031] The processing vessel 68 is electrically conductive and has a substantially cylindrical shape. A grounding wire 69 is electrically connected to the processing vessel 68, and the processing vessel 68 is grounded. The electrostatic chuck 61 and susceptor 63 are provided in the processing vessel 68 and support a wafer W to be processed. The electrostatic chuck 61 is a substantially disk-shaped member, formed, for example, by sandwiching an electrode for electrostatic chuck between a pair of ceramics. The susceptor 63 functions as a lower electrode and is provided on the lower surface of the electrostatic chuck 61. The susceptor 63 is formed in a substantially disk-shaped shape from a metal such as aluminum. A support table 64 is provided at the bottom of the processing vessel 68, and the susceptor 63 is supported on the upper surface of the support table 64. An electrode (not shown) is provided inside the electrostatic chuck 61, and the wafer W is attracted and held by the electrostatic chuck 61 by electrostatic force generated by applying a DC voltage to the electrode. A coolant flow path (not shown) through which a coolant flows is provided inside the support table 64, and the temperature of the wafer W held by the electrostatic chuck 61 is controlled by controlling the temperature of the coolant.

[0032] The power supply unit 80 includes high-frequency power supplies 81 and 83, and matching devices 82 and 84. The high-frequency power supply 81 for generating plasma is electrically connected to the susceptor 63 via the matching device 82. The high-frequency power supply 81 is configured to output high-frequency power at a frequency of, for example, 27 MHz to 100 MHz. The internal impedance of the high-frequency power supply 81 and the load impedance are matched by the matching device 82.

[0033] In order to attract ions to the wafer W by applying a bias to the wafer W, a high frequency power supply 83 is electrically connected to the susceptor 63 via a matching device 84. The high frequency power supply 83 is configured to output high frequency power at a frequency of, for example, 400 kHz to 13.56 MHz. Similar to the matching device 82, the matching device 84 matches the internal impedance of the high frequency power supply 83 with the load impedance. The operations of the high frequency power supplies 81 and 83 and the matching devices 82 and 84 are controlled by the control device 100.

[0034] An upper electrode 73 is disposed at the top of the processing vessel 68. The upper electrode 73 is disposed to face the susceptor 63. The upper electrode 73 is supported at the top of the processing vessel 68 and is grounded via the processing vessel 68. A gas diffusion chamber 76 formed in a substantially circular plate shape is formed in the center of the upper electrode 73. A plurality of gas discharge holes 77 for supplying processing gas into the processing vessel 68 are formed at the bottom of the upper electrode 73 so as to penetrate the bottom of the upper electrode 73.

[0035] A gas supply pipe 78 is connected to the gas diffusion chamber 76. As shown in FIG. 5, a gas supply source 79 is connected to the gas supply pipe 78, and the gas supply source 79 supplies a processing gas to the gas diffusion chamber 76 via the gas supply pipe 78. The processing gas supplied to the gas diffusion chamber 76 is introduced into the processing vessel 68 through the gas outlet holes 77. The processing gas supplied from the gas supply source 79 may contain an inert gas. The inert gas may be a rare gas (e.g., argon gas) or nitrogen gas.

[0036] An exhaust unit 90 is disposed below the processing vessel 68. The exhaust unit 90 includes an exhaust port 91, an exhaust chamber 92, an exhaust pipe 93, and an exhaust device 94. The exhaust port 91 is disposed on the bottom surface of the processing vessel 68. An exhaust chamber 92 is formed below the exhaust port 91, and an exhaust device 94 is connected to the exhaust chamber 92 via an exhaust pipe 93. By driving the exhaust device 94 (e.g., an exhaust pump), the processing vessel 68 is evacuated through the exhaust port 91, and the inside of the processing vessel 68 can be depressurized to a predetermined vacuum level.

[0037] (Control device) Next, a specific configuration of the control device 100 will be illustrated. The control device 100 controls the substrate processing system 1 partially or entirely. The control device 100 is configured to replace the liquid in the recess 202 of the wafer W, which has an uneven pattern formed on its surface Wa, with a solid reinforcing material 220a, and to perform a molecular weight reduction process on the wafer W to reduce the number of intermolecular bonds contained in the reinforcing material 220a while maintaining the reinforcing material 220a in a solid state. Note that the term "solid state" in this specification refers to a state in which the main component of a chemical solution, such as the processing solution L3, has solidified to the extent that it no longer flows after the solvent contained in the chemical solution has evaporated.

[0038] As shown in FIG. 6, the control device 100 includes, as functional components (hereinafter referred to as "functional modules"), a thermal treatment control unit 101, a development control unit 102, a molecular reduction control unit 103, and an etching control unit 104. The thermal treatment control unit 101 controls the thermal treatment unit U4. The development control unit 102 controls the valves 33 and the rotation drive unit 21 of each of the liquid supply units 30a, 30b, and 30c in the development unit U3. The molecular reduction control unit 103 controls the irradiation unit 42 in the irradiation unit U5. The etching control unit 104 controls the exhaust device 94 and the high-frequency power supplies 81 and 83 in the plasma processing device 10. The processes performed by the thermal treatment control unit 101, the development control unit 102, the molecular reduction control unit 103, and the etching control unit 104 correspond to the processes performed by the control device 100. Details of the processes performed by each functional module will be described later.

[0039] The control device 100 is composed of one or more control computers. For example, the control device 100 has a circuit 120 shown in FIG. 7. The circuit 120 has one or more processors 121, a memory 122, a storage 123, and an input / output port 124. The storage 123 has a computer-readable storage medium, such as a hard disk. The storage medium stores a program for causing the control device 100 to execute the substrate processing procedure described below. The storage medium may be a removable medium, such as a non-volatile semiconductor memory, a magnetic disk, or an optical disk. The memory 122 temporarily stores the program loaded from the storage medium of the storage 123 and the results of calculations by the processor 121. The processor 121 executes the program in cooperation with the memory 122 to configure each of the above-mentioned functional modules. The input / output port 124 inputs and outputs electrical signals to and from the components to be controlled in accordance with instructions from the processor 121.

[0040] When the control device 100 is configured with multiple control computers, the heat treatment control unit 101, development control unit 102, molecular conversion control unit 103, and etching control unit 104 may each be implemented by a separate control computer. Alternatively, each of these functional modules may be implemented by a combination of two or more control computers. In these cases, the multiple control computers may be connected to each other so that they can communicate with each other and coordinate the substrate processing procedures described below. Note that the hardware configuration of the control device 100 is not necessarily limited to one in which each functional module is configured by a program. For example, each functional module of the control device 100 may be configured by a dedicated logic circuit or an ASIC (Application Specific Integrated Circuit) that integrates such logic circuits.

[0041] [Substrate processing procedure] Next, as an example of a substrate processing method, a substrate processing procedure executed in the substrate processing system 1 will be described. The control device 100 controls the substrate processing system 1 to execute substrate processing including coating and developing processes, for example, in the following procedure. First, the control device 100 controls the transfer device A1 to transfer the wafer W in the carrier C to the shelf unit U10, and then controls the transfer device A7 to place the wafer W in a cell for the processing module 11.

[0042] Next, the control device 100 controls the transfer device A3 to transfer the wafer W from the shelf unit U10 to the coating unit U1 and heat treatment unit U2 in the processing module 11. The control device 100 also controls the coating unit U1 and heat treatment unit U2 to form an underlayer film on the front surface Wa of the wafer W. Thereafter, the control device 100 controls the transfer device A3 to return the wafer W on which the underlayer film has been formed to the shelf unit U10, and controls the transfer device A7 to place the wafer W in a cell for the processing module 12.

[0043] Next, the control device 100 controls the transfer device A3 to transfer the wafer W from the shelf unit U10 to the coating unit U1 and the heat treatment unit U2 in the processing module 12. The control device 100 also controls the coating unit U1 and the heat treatment unit U2 to form a resist film R on the underlying film of the wafer W. Thereafter, the control device 100 controls the transfer device A3 to return the wafer W to the shelf unit U10, and controls the transfer device A7 to place the wafer W in a cell for the processing module 13.

[0044] Next, the control device 100 controls the transfer device A3 to transfer the wafer W from the shelf unit U10 to each unit in the processing module 13. The control device 100 also controls the coating unit U1 and the heat treatment unit U2 to form an upper layer film on the resist film R of the wafer W. Thereafter, the control device 100 controls the transfer device A3 to transfer the wafer W to the shelf unit U11.

[0045] Next, the control device 100 controls the transfer device A8 to send the wafer W stored in the shelf unit U11 to the exposure device 3. Then, in the exposure device 3, an exposure process is performed on the resist film R formed on the wafer W. Thereafter, the control device 100 controls the transfer device A8 to receive the wafer W that has been subjected to the exposure process from the exposure device 3 and place the wafer W in a cell for the processing module 14 in the shelf unit U11.

[0046] Next, the control device 100 controls the transfer device A3 to transfer the wafer W from the shelf unit U11 to the thermal processing unit U4 of the processing module 14. Then, the control device 100 controls the execution of a series of processing procedures including the thermal processing associated with the development processing and the development processing (hereinafter referred to as the "development processing procedure"). The details of this development processing procedure will be described later. By executing the development processing procedure, a resist pattern is formed on the surface Wa of the wafer W. Thereafter, the control device 100 controls the plasma processing device 10 to perform an etching process using plasma on the wafer W using the resist pattern as a mask. This completes the substrate processing including the coating and development processes.

[0047] (Development processing procedure) Next, an example of a development process procedure will be described with reference to FIGS. 8 to 10. FIG. 8 is a flowchart showing an example of a development process procedure. First, the control device 100 executes step S01. In step S01, the heat treatment control unit 101 controls the heat treatment unit U4 to perform heat treatment at a predetermined temperature for a predetermined time on the wafer W that has been subjected to the exposure process. Then, the control device 100 controls the transfer device A3 to transfer the wafer W that has been subjected to the heat treatment before development to the development unit U3.

[0048] Next, the control device 100 executes step S02. In step S02, the development control unit 102 controls the developing unit U3 to supply the developer L1 to the resist film R formed on the front surface Wa of the wafer W. For example, the development control unit 102 controls the rotation drive unit 21 to rotate the wafer W at a predetermined rotation speed, while opening the valve 33 of the liquid supply unit 30a to discharge the developer L1 from the nozzle 34. This causes the resist film R to be developed, and a resist pattern 200 having a plurality of convex portions 201 and a plurality of concave portions 202 is formed on the front surface Wa of the wafer W (see FIG. 9(a)). Note that the portions of the resist film R that were not removed (e.g., portions that were not exposed to light during the exposure process) become the convex portions 201, and the portions of the resist film R that were removed (e.g., spaces between adjacent convex portions 201) become the concave portions 202.

[0049] Next, the control device 100 executes step S03. In step S03, the development control unit 102 controls the development unit U3 to supply the rinse liquid L2 to the front surface Wa of the wafer W. For example, the development control unit 102 controls the rotation drive unit 21 to rotate the wafer W at a predetermined rotation speed while opening the valve 33 of the liquid supply unit 30b to discharge the rinse liquid L2 from the nozzle 34. As shown in FIG. 9(a), the development control unit 102 either controls the rotation drive unit 21 to continue rotating the wafer W to such an extent that a portion of the discharged rinse liquid L2 (the rinse liquid 210) remains on the front surface Wa of the wafer W, or stops the rotation of the wafer W. At this time, as in the example of FIG. 9(a), each recess 202 may be completely filled with the rinse liquid 210. In other words, the height of the rinse liquid 210 (the shortest distance between the upper surface of the rinse liquid 210 and the front surface Wa) may be equal to or greater than the height of the protrusion 201. The height of the rinse liquid 210 is not limited to the example shown in FIG. 9( a ), and it is sufficient that at least a portion of the recess 202 is filled with the rinse liquid 210 .

[0050] Next, the control device 100 executes step S04. In step S04, the development control unit 102 controls the developing unit U3 to supply the processing liquid L3 to the wafer W having the rinse liquid 210 remaining on its surface Wa. Specifically, the development control unit 102 causes the developing unit U3 to start supplying the processing liquid L3 to the surface Wa of the wafer W when the rinse liquid 210 remains in each of the recesses 202 (e.g., when the rinse liquid 210 remains in almost all of the recesses 202). For example, the development control unit 102 controls the rotation drive unit 21 to rotate the wafer W at a predetermined rotation speed, while opening the valve 33 of the liquid supply unit 30c, causing the developing unit U3 to start discharging the processing liquid L3 from the nozzle 34. Thereafter, the development control unit 102 causes the developing unit U3 to continue rotating the wafer W and supplying the processing liquid L3 to the surface Wa of the wafer W for a predetermined time. As a result, the rinse liquid 210 on the front surface Wa is pushed out of the wafer W, and the rinse liquid 210 is replaced with the processing liquid L3. For example, after the replacement, the inside of the recess 202 may be completely filled with liquid (part of the processing liquid L3). It is sufficient that at least a part of the inside of the recess 202 is filled with the processing liquid L3.

[0051] Next, the control device 100 executes step S05. In step S05, the development control unit 102 controls the developing unit U3 to dry the processing liquid L3 filling the recess 202. For example, the development control unit 102 controls the rotation drive unit 21 to rotate the wafer W until the liquid processing liquid L3 becomes solid. As a result, as shown in FIG. 9(b), a solid reinforcing material 220a is formed in the recess 202. For example, if the processing liquid L3 contains a polymer, spin-drying the wafer W volatilizes the solvent contained in the processing liquid L3, and multiple polymers dispersed in the solvent become entangled. As a result, a solid reinforcing material 220a is formed in the recess 202. As described above, the liquid supply unit 30c and the spin holder 20 of the developing unit U3 constitute a replacement processing unit.

[0052] By performing steps S04 and S05, the rinse liquid 210 in the recess 202 is replaced with the reinforcing material 220a in a solid state. At this time, as in the example of FIG. 9(b), the reinforcing material 220a may be formed in the recess 202 so as to fill almost the entire space in the recess 202. As an example, the reinforcing material 220a may be formed in the recess 202 so that the height of the reinforcing material 220a is approximately equal to the height of the protrusion 201. Note that the height of the reinforcing material 220a is not limited to the example of FIG. 9(b), as long as at least a portion of the recess 202 is filled with the reinforcing material 220a. Furthermore, the reinforcing material 220a may be formed to a height exceeding the height of the protrusion 201 (the depth of the recess 202). After performing step S05, the control device 100 controls the transfer device A3 to transfer the wafer W having the reinforcing material 220a formed in the recess 202 to the irradiation unit U5.

[0053] Next, the control device 100 executes step S06. In step S06, the molecular weight reduction control unit 103 controls the irradiation unit U5 to irradiate the reinforcing material 220a with energy rays. For example, the molecular weight reduction control unit 103 controls the irradiation unit 42 to irradiate the entire surface Wa of the wafer W with energy rays. The type of energy rays may be determined based on the type of processing liquid L3 (the type of polymer contained in the reinforcing material 220a). Irradiating the reinforcing material 220a with energy rays reduces the number of intermolecular bonds contained in the reinforcing material 220a while the reinforcing material 220a remains in a solid state (without becoming a liquid). For example, if the reinforcing material 220a contains a polymer, the degree of polymerization of the polymer decreases. As an example, each polymer contained in the reinforcing material 220a may be decomposed into multiple polymers having a degree of polymerization (e.g., tens to hundreds) lower than the degree of polymerization of the polymer (e.g., thousands to tens of thousands). Each polymer contained in the reinforcing material 220a may be decomposed into a plurality of monomers each having one constitutional unit, a plurality of dimers each having two constitutional units, or a plurality of trimers each having three constitutional units.

[0054] In this way, the molecular weight reduction control unit 103 applies a molecular weight reduction process to the wafer W, which reduces the number of intermolecular bonds (e.g., the degree of polymerization of polymers) contained in the reinforcing material 220a while maintaining the reinforcing material 220a in a solid state by irradiating the reinforcing material 220a with energy rays. As a result, as shown in FIG. 9(c), the reinforcing material 220a that has been subjected to the molecular weight reduction process (hereinafter referred to as "reinforcing material 220b") is formed in the recessed portion 202. When applying the molecular weight reduction process, the molecular weight reduction control unit 103 may reduce the number of intermolecular bonds contained in the reinforcing material 220a to a level at which the reinforcing material 220b is more likely to sublimate than the resist pattern 200 (protrusion 201).

[0055] Here, "sublimation" in this specification refers to the transition of the reinforcing material 220b from a solid state to a gaseous state without passing through a liquid state. This "sublimation" includes not only a change from a solid state to a gaseous state (a change from a solid phase to a gaseous phase) but also a transition of the reinforcing material 220b from a solid state to a gaseous state accompanied by a chemical change. For example, the transition from a solid state to a gaseous state accompanied by a chemical change includes etching of the reinforcing material 220b by subjecting the reinforcing material 220b to a plasma etching process. Here, "ease of sublimation" refers to the ease of sublimation of the reinforcing material 220b in an environment for sublimating the reinforcing material 220b (e.g., the amount of sublimation per unit time). For example, a state in which the reinforcing material 220b is more likely to sublimate than the resist pattern 200 refers to a state in which the reinforcing material 220b is etched more than the resist pattern 200 under the conditions of the plasma process for etching the reinforcing material 220b.

[0056] FIG. 10 illustrates the change in the number of bonds (degree of polymerization) within a polymer when a polymer containing polymethyl methacrylate is included in the treatment liquid L3. The degree of polymerization of each polymer contained in the reinforcing material 220a is represented by "L+M+N+···" (L, M, and N are positive integers). When the irradiation unit U5 irradiates the reinforcing material 220a with energy rays, some of the "C-CH2" bonds that form the main chain connecting the monomers are broken. As a result, in the reinforcing material 220b, compounds with "L" monomer units (e.g., polymers with a degree of polymerization of "L"), compounds with "M" monomer units, and compounds with "N" monomer units are formed. For example, when multiple polymers with reduced degrees of polymerization are formed by irradiation with energy rays, the reduced degree of polymerization changes the substance from a stable state to one that is more susceptible to sublimation.

[0057] After executing step S06, the control device 100 controls the transfer device A3 to transfer the wafer W on which the reinforcing material 220b has been formed to the heat treatment unit U4. Then, the control device 100 executes step S07. In step S07, the heat treatment control unit 101 controls the heat treatment unit U4 to perform a heat treatment at a predetermined temperature for a predetermined time on the wafer W that has been subjected to the development treatment by supplying the developer L1. Then, the control device 100 controls the transfer device A3 to return the wafer W that has been subjected to the heat treatment after development to the shelf unit U10, and controls the transfer device A7 and the transfer device A1 to return the wafer W into the carrier C. Thereafter, the control device 100 controls the transfer mechanism 19 to transfer the wafer W in the carrier C to the plasma processing device 10.

[0058] Next, the control device 100 executes step S08. In step S08, the etching control unit 104 controls the plasma processing apparatus 10 to perform a plasma etching process on the reinforcing material 220b. In step S08, the wafer W is first placed on the electrostatic chuck 61 of the plasma processing apparatus 10 so that the surface Wa on which the resist pattern 200 is formed faces upward. Then, the etching control unit 104 controls the plasma processing apparatus 10 to supply a processing gas for plasma generation from the gas supply source 79 into the processing vessel 68. The processing gas may be determined, for example, depending on the type of polymer contained in the processing solution L3. Then, the etching control unit 104 controls the power supply unit 80 to continuously apply high-frequency power to the susceptor 63, which is the lower electrode, by the high-frequency power supplies 81 and 83. This forms a high-frequency electric field between the upper electrode 73 and the electrostatic chuck 61.

[0059] By forming a high-frequency electric field, plasma of the processing gas is generated within the processing chamber 68, and the reinforcing material 220b is etched by the plasma. At this time, since the reinforcing material 220a has been subjected to a low-molecular-weight treatment to form the reinforcing material 220b, the reinforcing material 220b is more likely to sublimate than the resist pattern 200. Therefore, the resist pattern 200 (protrusions 201) is not etched, but the reinforcing material 220b is etched. As a result, as shown in FIG. 9(d), the reinforcing material 220b in the recesses 202 is sublimated and removed. In this way, the plasma processing apparatus 10 constitutes a removal unit that sublimes and removes the reinforcing material (reinforcing material 220b) that has been subjected to the low-molecular-weight treatment. This completes the series of development processing steps.

[0060] By performing the processes of steps S04 to S08, the rinse liquid 210 is removed from the surface Wa of the wafer W. In this development process, the rinse liquid 210 discharged onto the surface Wa of the wafer W is once replaced with the reinforcing material 220a (reinforcing material 220b), and the reinforcing material 220b is removed (sublimated) by etching, thereby removing the rinse liquid 210 from the surface Wa of the wafer W. Looking at the state inside the recess 202, there is a transition from a state in which a liquid (rinse liquid 210) is contained to a state in which a solid (reinforcing materials 220a, 220b) is contained, and then there is a transition from a state in which a solid is contained to a state in which a gas (air, etc.) is contained.

[0061] [Effects of the embodiment] The substrate processing method according to the present embodiment described above includes replacing the liquid in the recess 202 of the wafer W having an uneven pattern formed on the surface Wa with a solid reinforcing material 220a, and performing a molecular weight reduction process on the wafer W to reduce the number of intermolecular bonds contained in the reinforcing material 220a while maintaining the reinforcing material 220a in a solid state.

[0062] The substrate processing system 1 includes a replacement processing unit that replaces the liquid in the recess 202 of the wafer W having an uneven pattern formed on the surface Wa with a solid reinforcing material 220a, and a molecular weight reduction processing unit that performs a molecular weight reduction process on the wafer W to reduce the number of bonds between molecules contained in the reinforcing material 220a while maintaining the reinforcing material 220a in a solid state.

[0063] In this substrate processing method and substrate processing system 1, the liquid in the recesses 202 of the uneven pattern is replaced with solid reinforcing material 220a, and the reinforcing material 220a is subjected to a low-differentiation process. By reducing the molecular weight of the reinforcing material 220a, a wafer W is formed from which the reinforcing material 220a (reinforcing material 220b) can be removed while leaving the uneven pattern. Removing the reinforcing material 220b removes substances from within the recesses 202, and therefore liquids such as the rinse liquid 210 are removed from the recesses 202.

[0064] When removing (drying) a liquid such as the rinse liquid 210 from the recesses, the wafer W is rotated at a predetermined rotation speed to spin off and remove the liquid by centrifugal force. In this case, the recesses 202 transition from a state in which the liquid (rinse liquid) is contained to a state in which the gas (air) is contained. During this transition, if the liquid remains in some of the recesses 202, the pattern (protrusions 201) may collapse due to surface tension. In the substrate processing method and substrate processing system 1 of this embodiment, the transition from a state in which the liquid is contained to a state in which the gas is contained does not occur in the recesses 202, so pattern collapse caused by the liquid remaining in some of the recesses of the uneven pattern is unlikely to occur. In other words, this substrate processing method and substrate processing system 1 are effective in suppressing pattern collapse.

[0065] In the above embodiment, when the molecular weight reduction process is performed, the number of intermolecular bonds contained in the reinforcing material 220a is reduced to a level at which the reinforcing material 220b is more likely to sublimate than the concave-convex pattern. In this case, a wafer W is formed from which the reinforcing material 220b can be more reliably removed while leaving the concave-convex pattern.

[0066] The substrate processing method according to the above embodiment further includes sublimating and removing the reinforcing material (reinforcing material 220b) that has been subjected to a low-molecular-weight treatment. Because the reinforcing material 220b has been subjected to a low-molecular-weight treatment, it is more likely to sublimate than the concave-convex pattern. Therefore, the reinforcing material 220b can be sublimated and removed, leaving the concave-convex pattern. In this method, when removing (drying) the liquid in the recess 202, the material in the recess 202 transitions from liquid to solid to gas in this order, making it possible to prevent pattern collapse caused by the transition from a liquid-filled state to a gas-filled state in the recess 202.

[0067] In the above embodiment, sublimating and removing the reinforcing material 220b includes subjecting the reinforcing material 220b to an etching process using plasma. In this case, since the reinforcing material 220b has been subjected to a low-molecular-weight treatment, the reinforcing material 220b in a solid state can be sublimated by an etching process using plasma while leaving the uneven pattern. The plasma etching process using plasma on the reinforcing material 220b is performed by the plasma processing apparatus 10. Therefore, the plasma processing apparatus 10 can be used not only for the etching process on the wafer W using the resist pattern 200 as a mask, but also for the etching process on the reinforcing material 220b, thereby simplifying the configuration of the substrate processing system 1.

[0068] In the above embodiment, replacing with the reinforcing material 220a includes supplying the processing liquid L3 onto the front surface Wa of the wafer W to replace the liquid in the recess 202 with the processing liquid L3, and drying the processing liquid L3 to form the reinforcing material 220a in the recess 202. In this case, it is easy to transition the state of the recess 202 from a state in which a liquid is contained to a state in which a solid is contained.

[0069] In the above embodiment, the concave-convex pattern includes a plurality of recesses 202. Supplying the processing liquid L3 to the front surface Wa of the wafer W includes starting the supply of the processing liquid L3 to the front surface Wa of the wafer W in a state in which liquid remains in each of the plurality of recesses 202. In this case, the possibility that liquid remains in some of the plurality of recesses 202 is reduced, and pattern collapse caused by replacement of the liquid in the recesses 202 (e.g., the rinse liquid 210) with the processing liquid L3 is suppressed.

[0070] In the above embodiment, the reinforcing material 220a (treatment liquid L3) contains a polymer containing at least one of polymethyl acrylate, polymethacrylic acid, polyvinyl alcohol, ultraviolet curable resin, and polymethyl methacrylate. In this case, the degree of polymerization of the polymer contained in the reinforcing material 220b is lower than the degree of polymerization of the polymer contained in the reinforcing material 220a. The reduced degree of polymerization makes the substance more reactive, so it is possible to remove the reinforcing material 220a by reacting (sublimating) it under conditions that do not cause the concave-convex pattern to react.

[0071] While it is conceivable to supply a treatment liquid containing a polymer with a low degree of polymerization and high reactivity, such a treatment liquid is unstable and difficult to handle both before and after supply. In the above embodiment, the treatment liquid is decomposed from a polymer with a high degree of polymerization (e.g., a degree of polymerization of several thousand to several tens of thousands) to a polymer with a low degree of polymerization (e.g., a degree of polymerization of several tens to several hundreds), making it easier to handle the treatment liquid during supply. Furthermore, when the treatment liquid is dried, the polymers with a high degree of polymerization entangle with each other to form a solid reinforcing material 220a, making it easy to transition the material in the recesses 202 from a liquid to a solid. Depending on the type of material contained in the treatment liquid, a thin film may be formed on the surface of the protrusions 201, potentially reducing the roughness of the resist pattern 200.

[0072] Although one embodiment has been described above, the present disclosure is not necessarily limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present disclosure.

[0073] (Variation 1) In the molecular reduction process, thermal energy may be applied to the wafer W in addition to the energy beam. In the process of step S06, the control device 100 may apply thermal energy to the reinforcing material 220a in addition to irradiating it with energy beams, thereby performing the molecular reduction process on the reinforcing material 220a. For example, the molecular reduction control unit 103 may apply thermal energy to the reinforcing material 220a in the irradiation unit U5 by placing the wafer W on a heating plate 43 (described later) and heating the wafer W. In this case, the irradiation unit U5 may further include a heating unit 41 (a molecular reduction processing unit) (see FIG. 4).

[0074] The heating unit 41 heats the reinforcing material 220a formed in the recessed portion 202 of the resist pattern 200. As the reinforcing material 220a is heated, the resist pattern 200 (protruding portion 201) is also heated. For example, the heating unit 41 has a heating plate 43 and a lifting mechanism 44. The heating plate 43 is a plate-shaped heating element that supports a horizontally placed wafer W and heats the wafer W. For example, the heating plate 43 has multiple heaters built in as heat sources. Specific examples of the heaters include an electric heating wire heater.

[0075] The lifting mechanism 44 raises and lowers the wafer W above the heating plate 43. For example, the lifting mechanism 44 has a plurality of (for example, three) lifting pins 45 and a lifting driver 46. The plurality of lifting pins 45 protrude upward so as to penetrate the heating plate 43. The lifting driver 46 raises and lowers the plurality of lifting pins 45, causing their tips to appear and disappear above the heating plate 43. This makes it possible to raise and lower the wafer W above the heating plate 43.

[0076] The depolymerization control unit 103 may control the heating unit 41 to heat the wafer W with the hot plate 43 while the lifting pins 45 are lowered by the lifting drive unit 46. The depolymerization control unit 103 may also control the irradiation unit 42 to irradiate the front surface Wa with energy rays while the wafer W is raised (brought closer to the irradiation unit 42) by driving the lifting drive unit 46. The heating unit 41 and the irradiation unit 42 do not necessarily have to be configured as a single unit, and may be configured as mutually independent units.

[0077] (Variation 2) In the molecular decomposition treatment, thermal energy may be applied to the wafer W instead of energy rays. The control device 100 (decomposition control unit 103) may apply thermal energy to the wafer W instead of irradiating it with energy rays, thereby performing the molecular decomposition treatment on the reinforcing material 220a. In this case, the irradiation unit 42 may be omitted from the irradiation unit U5. Alternatively, the control device 100 may perform the molecular decomposition treatment by applying thermal energy to the reinforcing material 220a in the heat treatment unit U4 instead of the above-mentioned irradiation unit U5. Note that the control device 100 may control the heat treatment unit U4 so that the post-development heat treatment and the molecular decomposition treatment are performed in parallel.

[0078] When thermal energy is applied to the reinforcing material 220a containing a polymer containing polymethyl methacrylate, some of the "C-CH2" bonds are broken, reducing the number of intermolecular bonds, just as in the case of irradiation with energy rays (see Figure 10). In this way, the application of thermal energy reduces the number of intermolecular bonds, forming multiple compounds, and the substance changes from a stable state to one that is more susceptible to sublimation.

[0079] In the above-described first and second modifications and the above-described embodiment, the concave-convex pattern is a resist pattern 200 formed by subjecting an exposed resist film R to a development process. The molecular weight reduction process includes applying at least one of thermal energy and energy rays to the resist pattern 200 and the reinforcing material 220a. In this case, when the developer L1 used for development is washed away with a rinse liquid L2, pattern collapse caused by the removal of the rinse liquid L2 is suppressed.

[0080] (Variation 3) In order to sublimate the reinforcing material 220b, the wafer W may be placed in a reduced-pressure space instead of or in addition to performing an etching process using plasma. In the process of step S08, instead of performing an etching process using plasma, the control device 100 may place the wafer W on which the reinforcing material 220b is formed in the processing chamber 68 of the plasma processing device 10, thereby sublimating (evaporating) the reinforcing material 220b. That is, the control device 100 may perform a process of sublimating the reinforcing material 220b by placing the wafer W in a reduced-pressure space. Alternatively, the control device 100 may sublimate a portion of the reinforcing material 220b by placing the wafer W in the reduced-pressure space (in the processing chamber 68) of the plasma processing device 10, and then sublimate the remaining portion of the reinforcing material 220b by performing an etching process using plasma. Even in these cases, the plasma processing device 10 can be used not only for the etching process of the wafer W using the resist pattern 200 as a mask, but also for the etching process of the reinforcing material 220b, thereby simplifying the configuration of the substrate processing system 1.

[0081] The substrate processing system 1 may include a decompression unit (removal unit) capable of forming a decompressed space (a space that is substantially in a vacuum state) instead of the plasma processing apparatus 10, and the reinforcing material 220b may be removed in the decompression unit. The decompression unit may be provided inside the coating and developing apparatus 2. In this case, all of the above-mentioned development process steps may be performed in the coating and developing apparatus 2. When the reinforcing material 220b is sublimated in a decompressed space, the control device 100 may reduce the number of intermolecular bonds (e.g., the degree of polymerization) in the decompression process in step S06 so that the reinforcing material 220b is more likely to sublimate than the resist pattern 200 when the wafer W is placed in the decompressed space after the decompression process.

[0082] In the substrate processing method according to Modification 3, sublimating and removing the reinforcing material 220b includes sublimating the reinforcing material 220b by placing the wafer W in a decompressed space. Since the reinforcing material 220b has been subjected to a low-molecular-weight treatment, placing the wafer W in a decompressed space allows the reinforcing material 220b in a solid state to evaporate without first becoming liquid, while leaving the uneven pattern.

[0083] (Variation 4) A resist film R may be used that contains a cross-linking agent that promotes cross-linking in response to irradiation with energy rays or heating in the depolymerization process. In this case, when the entire surface Wa of the wafer W is irradiated with energy rays or the entire wafer W is heated in step S06, the reinforcing material 220a is subjected to the depolymerization process, and a cross-linking reaction is promoted in the protrusions 201 formed from the resist film R, causing the protrusions 201 to harden.

[0084] In the substrate processing method according to Modification 4, the resist pattern 200 contains a cross-linking agent that promotes cross-linking in response to the application of at least one of thermal energy and energy rays in the depolymerization process. In this case, the protrusions 201 are hardened in response to the application of energy rays or thermal energy for the depolymerization process. This increases the selectivity (contrast ratio) between the reinforcing material 220b and the resist pattern 200, making it easy to remove the reinforcing material 220b in the recesses 202 while leaving the resist pattern 200. Furthermore, the application of energy for the depolymerization process can also be effectively used to harden the protrusions 201.

[0085] (Variation 5) When a negative resist pattern is used, a molecular weight reduction process may be performed to reduce the number of intermolecular bonds within the reinforcing material and also to improve the etching resistance of the resist pattern. This "etching resistance" refers to the resistance to wear and erosion of the resist pattern 200 (protruding portions 201). By improving the etching resistance in the molecular weight reduction process, the progress of wear and erosion of the protruding portions 201 is suppressed (e.g., the amount of etching is reduced) in the etching process after the molecular weight reduction process, compared to when the molecular weight reduction process is not performed. Examples of the etching process after the molecular weight reduction process include an etching process for sublimating the reinforcing material and an etching process of the wafer W using the resist pattern 200 as a mask. Furthermore, even if an organic solvent developer penetrates and softens the surface layer of the resist pattern 200 during the development process, the energy applied in the molecular weight reduction process may harden the softened portion of the surface layer.

[0086] 11(a) to 13, an example of a substrate processing procedure according to Modification 5 will be described in detail below. In the substrate processing procedure according to Modification 5, the control device 100 also controls the coating / developing apparatus 2 to perform the same processing as the substrate processing including the developing processing procedure described above (see FIG. 8).

[0087] FIG. 11(a) illustrates an exposure process. In this exposure process, a resist film R formed on the surface Wa of a wafer W is irradiated (exposed) with energy beams from an exposure light source 221. In the exposure process, a mask 222 for blocking the irradiation of the energy beams is disposed between the light source 221 and the wafer W. The mask 222 has an opening 222a formed therein corresponding to a portion of the resist film R to be removed. In this case, the energy beams are irradiated onto a region Ra of the resist film R directly below the opening 222a (a region overlapping with the opening 222a when the surface Wa is viewed from a direction perpendicular to the surface Wa). Furthermore, due to the diffusion of light or a dimensional error of the mask 222, a small amount of energy beams is also irradiated onto a region Rb surrounding the region Ra. In this case, the energy beams are irradiated onto the region Rb in an amount sufficient to prevent the region Rb from being removed during the development process.

[0088] After the exposure process, the control device 100 controls the developing unit U3 to supply the developer L1 to the resist film R that has been exposed, similar to step S02 described above. By supplying the developer L1 to the resist film R, the regions Ra (sufficiently exposed regions) that were irradiated with the exposure energy beam during the exposure process are removed. As a result, similar to the above-described development process procedure, a resist pattern 200A having a plurality of convex portions 201A and a plurality of concave portions 202A is formed on the surface Wa. Regions Rb that have been irradiated with the exposure energy beam but with an insufficient dose remain without being removed by the developer L1, forming the surfaces (portions including the surfaces) of the convex portions 201A. For example, as shown in FIG. 11(b), the regions Rb form the side surfaces of the convex portions 201A and a portion of the upper surface connected to the side surfaces.

[0089] After the resist pattern 200A is formed, the control device 100 sequentially supplies a rinse liquid L2 and a processing liquid L3 to the front surface Wa of the wafer W, similar to steps S03 and S04 described above. As shown in FIG. 12(a), when the developer L1 in the recesses 202A is replaced with the rinse liquid L2 by the supply of the rinse liquid L2, the height of the rinse liquid L2 on the front surface Wa may be equal to or greater than the height of the protrusions 201A. That is, the distance between the upper surface of the rinse liquid L2 and the front surface Wa may be equal to or greater than the distance between the upper surface of the protrusions 201A and the wafer W. Furthermore, when the rinse liquid L2 in the recesses 202A is replaced with the processing liquid L3 by the supply of the processing liquid L3, and before the processing liquid L3 becomes solid, the height of the processing liquid L3 on the front surface Wa may be equal to or greater than the height of the protrusions 201A. By setting the height of the rinsing liquid L2 or the processing liquid L3 to be equal to or greater than the height of the convex portions 201A, the liquid fills all the spaces of the concave portions 202A over the entire surface Wa of the wafer W. This makes it possible to suppress pattern collapse caused by variations in the amount of liquid filled between adjacent concave portions 202A (differences in surface tension).

[0090] After the inside of the recessed portion 202A is replaced with the treatment liquid L3, the control device 100 controls the developing unit U3 to form a reinforcing material 220a in the recessed portion 202A, as in step S05. At this time, the height of the reinforcing material 220a formed in the recessed portion 202A may be higher than the height of the convex portion 201A. The height position of the upper surface of the reinforcing material 220a (the height position of the upper surface of the treatment liquid L3 before the formation of the reinforcing material 220a) may be set to an extent that allows energy rays irradiated in the next process to reach the convex portion 201A.

[0091] After the reinforcing material 220a is formed in the recessed portion 202A, the control device 100 may control the irradiation unit U5 to apply energy rays to the resist pattern 200 (protruding portion 201A) and the reinforcing material 220a, as in step S06. The application of energy rays may reduce the number of intermolecular bonds contained in the reinforcing material 220a and improve the etching resistance of the region Rb including the surface of the resist pattern 200A (protruding portion 201A).

[0092] The irradiation unit 42 shown in FIG. 12(b) is configured to irradiate both the region Rb of the convex portion 201A and the reinforcing material 220a with energy rays. The type of energy rays irradiated from the irradiation unit 42 is preset so as to reduce the number of intermolecular bonds contained in the reinforcing material 220a and improve the etching resistance of the region Rb. For example, the type of energy rays irradiated from the irradiation unit 42 is set so as to cause a chemical reaction in the resist film R (convex portion 201A) different from the chemical reaction caused by irradiation with the energy rays for exposure. Application of energy rays to the reinforcing material 220a forms a reinforcing material (reinforcing material 220b) that has been subjected to a low-molecular-weight treatment, and application of energy rays to the region Rb improves the etching resistance of the region Rb. The irradiation unit 42 shown in FIG. 12(b) may also irradiate energy rays in a direction inclined relative to a direction perpendicular to the surface Wa so that the energy rays irradiated from the light source reach the lower part of the side surface of the convex portion 201A (the portion of the region Rb that constitutes the side surface).

[0093] The control device 100 may control the irradiation unit U5 etc. to apply thermal energy to the reinforcing material 220a and the resist pattern 200A (protrusion 201A) formed in the recess 202A instead of or in addition to the irradiation of energy rays. The application of this thermal energy may reduce the number of intermolecular bonds in the reinforcing material 220a and improve the etching resistance of the region Rb.

[0094] After the reinforcing material 220b is formed in the recess 202A, the control device 100 controls the plasma processing device 10 and the like to remove the reinforcing material 220b, as in step S08. As a result, a resist pattern 200A is formed on the surface Wa from which the liquid and solid have been removed from the recess 202A, as shown in Fig. 13. Because the etching resistance of the region Rb is improved, the progress of wear and erosion of the region Rb is suppressed during the process of step S08 or the etching process of the wafer W performed after the development process.

[0095] In the substrate processing method according to the fifth modification, the development process includes forming a resist pattern 200A by removing the regions Ra of the resist film R that were exposed in the exposure process. In this substrate processing method, the molecular weight reduction process reduces the number of intermolecular bonds contained in the reinforcing material 220a and improves the etching resistance of the regions Rb, including the surface of the resist pattern 200A. In the etching process, portions of the convex portions that are slightly irradiated with the exposure energy beam may be worn or eroded, potentially reducing the accuracy of etching using the resist pattern. In contrast, the above method improves the etching resistance of the regions Rb, thereby preventing a reduction in etching accuracy due to the slightly exposed portions of the convex portions 201A.

[0096] (Variation 6) A resist pattern containing a material that undergoes a dehydration condensation reaction when subjected to energy rays or thermal energy may be used. This resist pattern containing a material that undergoes a dehydration condensation reaction (hereinafter referred to as "resist pattern 200B") may contain a metal to improve etching resistance. The resist pattern 200B may have a property such that the results of the development process for forming the pattern are more susceptible to moisture than to the ambient temperature of the wafer W. The resist pattern 200B may be negative, similar to the resist pattern 200A according to Modification 5.

[0097] 14 shows the state of the surface Wa after a resist pattern 200B including a plurality of convex portions 201B and a plurality of concave portions 202B is formed, and then reinforcing materials 220a are formed in the concave portions 202B. The height of the reinforcing materials 220a formed in the concave portions 202B may be approximately the same as the height of the convex portions 201B, or the upper surfaces of the convex portions 201B may be exposed. The control device 100 may control the irradiation unit U5 including the irradiation section 42 so that the resist pattern 200B (convex portions 201B) and the reinforcing materials 220a are irradiated with energy rays. The exposed upper surfaces of the convex portions 201B make it easier to irradiate the convex portions 201B with energy rays.

[0098] The control device 100 may control the irradiation unit U5 etc. to apply thermal energy to the resist pattern 200B (protrusions 201B) and the reinforcing material 220a instead of or in addition to the energy rays. Applying energy rays or thermal energy to the resist pattern 200B (protrusions 201B) promotes crosslinking by dehydration condensation within the resist pattern 200B (protrusions 201B), resulting in hardening of the protrusions 201B.

[0099] In the substrate processing method according to the sixth modification, the resist pattern 200B contains a material that undergoes crosslinking by dehydration condensation when at least one of thermal energy and energy rays is applied during the depolymerization process. In this case, the convex portions 201B are hardened by the application of energy rays or thermal energy for the depolymerization process. This increases the selectivity (contrast ratio) between the reinforcing material 220b and the resist pattern 200B, making it easy to remove the reinforcing material 220b in the recesses 202B while leaving the resist pattern 200B. Furthermore, the application of energy for the depolymerization process can also be effectively used to harden the convex portions 201B.

[0100] (Other variations) When replacing the rinse liquid in the recess 202 with the solid reinforcing material, the developing unit U3 may replace the rinse liquid with the reinforcing material without drying the rinse liquid in the recess 202 (without emptying the recess 202). For example, the developing unit U3 may supply a powdered substance containing a polymer to the rinse liquid on the surface Wa, and remove the rinse liquid after the solid matter has precipitated. Alternatively, the developing unit U3 may dissolve a powdered substance containing a polymer in the rinse liquid on the surface Wa, and then dry the rinse liquid in which the substance is dissolved, thereby solidifying the rinse liquid.

[0101] The height of the reinforcing materials 220a and 220b formed in the recess 202 may be approximately the same as that of the resist pattern 200 (protrusion 201), or may be lower than that of the protrusion 201. The height of the reinforcing materials 220a and 220b may be higher than that of the protrusion 201. In this case, the reinforcing materials 220a (reinforcing materials 220b) located in the recess 202 may be connected to each other by a film-like reinforcing material above the protrusion 201. It is sufficient that the reinforcing materials 220a and 220b fill at least a portion of the recess 202.

[0102] The substrate processing system 1 may be any system as long as it includes a replacement processing unit that replaces the liquid in the recess 202 with a solid reinforcing material, a molecular weight reduction processing unit that performs molecular weight reduction processing on the reinforcing material, and a control device that can control these. In the substrate processing system 1, the plasma processing device 10 may be provided in the coating / developing device 2.

[0103] The substrate to be processed is not limited to a semiconductor wafer, but may be, for example, a glass substrate, a mask substrate, or a flat panel display (FPD). [Explanation of symbols]

[0104] 1...substrate processing system, 2...coating / developing apparatus, U3...developing unit, U5...irradiation unit, 10...plasma processing apparatus, 200, 200A, 200B...resist pattern, 201, 201A, 201B...protruding portion, 202, 202A, 202B...recessed portion, 220a, 220b...reinforcing material, W...wafer, Wa...surface.

Claims

1. a substrate having a metal-containing resist pattern formed on its surface and a reinforcing material formed so as to fill at least a portion of the recesses of the metal-containing resist pattern, and irradiating the substrate with energy rays to cause a dehydration condensation reaction in the metal-containing resist pattern; the reinforcing material is in a solid state; The method further includes subjecting the substrate to a molecular weight reduction treatment that reduces the number of bonds between molecules contained in the reinforcing material while maintaining the reinforcing material in a solid state, The substrate processing method, wherein the low-molecular-weight processing is performed simultaneously with the dehydration condensation reaction caused by irradiating the substrate with the energy beam.

2. A substrate processing method as described in claim 1, wherein causing the dehydration condensation reaction includes improving the etching resistance of the uneven pattern.

3. 3. The substrate processing method according to claim 1, wherein the number of intermolecular bonds contained in the reinforcing material is reduced to a level at which the reinforcing material is more likely to sublimate than the uneven pattern when the molecular reduction process is performed.

4. 4. The substrate processing method according to claim 1, further comprising removing the reinforcing material by sublimation after causing the dehydration condensation reaction.

5. The substrate processing method according to claim 4 , wherein removing the reinforcing material by sublimation includes sublimating the reinforcing material by placing the substrate in a reduced pressure space.

6. 6. The substrate processing method according to claim 4, wherein removing the reinforcing material by sublimation includes subjecting the reinforcing material to an etching process using plasma.

7. The method further comprises removing the reinforcing material by sublimation after the low-molecular-weight treatment, 4. The substrate processing method according to claim 1, wherein the step of reducing the molecular weight of the substrate and the step of removing the reinforcing material by sublimation are carried out in different apparatuses.

8. A method for producing a substrate having a metal-containing resist pattern formed on its surface and a reinforcing material formed so as to fill at least a portion of the recesses of the metal-containing resist pattern, the method comprising irradiating an energy beam onto the substrate to cause a dehydration condensation reaction in the metal-containing resist pattern; the reinforcing material is in a solid state; The method further includes subjecting the substrate to a molecular weight reduction treatment that reduces the number of bonds between molecules contained in the reinforcing material while maintaining the reinforcing material in a solid state, the reinforcing material is removed from the recess after the dehydration condensation reaction and the low-molecular-weight treatment; The substrate processing method, wherein the dehydration condensation reaction and the low-molecular-weight treatment are performed in an apparatus different from an apparatus that removes the reinforcing material.

9. A computer-readable storage medium storing a program for causing an apparatus to execute the substrate processing method according to any one of claims 1 to 8.

10. an irradiation unit that irradiates, with energy rays, a substrate having a surface on which a concave-convex pattern of a resist containing a metal is formed and on which a reinforcing material is formed so as to fill at least a part of the concave portions of the concave-convex pattern; the irradiation unit causes a dehydration condensation reaction in the concave-convex pattern by irradiating the energy beam, the reinforcing material is in a solid state; the irradiation unit also performs a molecular reduction process on the substrate to reduce the number of bonds between molecules contained in the reinforcing material while maintaining the reinforcing material in a solid state; The substrate processing apparatus is configured such that the low-molecular-weight treatment is performed simultaneously with the dehydration condensation reaction occurring as a result of the energy beam being irradiated onto the substrate.

11. A substrate having a surface on which a concave-convex pattern of a resist containing a metal is formed, and a reinforcing material is formed so as to fill at least a part of the concave portions of the concave-convex pattern, comprising an irradiation unit for irradiating an energy beam onto the substrate; the irradiation unit causes a dehydration condensation reaction in the concave-convex pattern by irradiating the energy beam, the reinforcing material is in a solid state; the irradiation unit also performs a molecular reduction process on the substrate to reduce the number of bonds between molecules contained in the reinforcing material while maintaining the reinforcing material in a solid state; the reinforcing material is removed from the recess after the dehydration condensation reaction and the low-molecular-weight treatment; the irradiation unit that causes the dehydration condensation reaction and performs the low-molecular-weight treatment is an apparatus different from an apparatus that removes the reinforcing material.

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