JP2020129619A - Substrate processing method and substrate processing apparatus - Google Patents

Abstract

To provide a substrate processing method and substrate processing apparatus effective for suppression of pattern collapse of an uneven pattern.SOLUTION: The substrate processing method includes replacing liquid in a recessed part of a substrate formed with an uneven pattern on a surface thereof by a reinforcement material under a solid state, and executing, on the substrate, low molecular processing for decreasing the number of bonds between molecules contained in the reinforcement material while maintaining the reinforcement material under a solid state.SELECTED DRAWING: Figure 8

Description

The present disclosure relates to a substrate processing method and a substrate processing apparatus.

Patent Document 1 discloses a substrate drying method (substrate processing method) for removing a liquid on a substrate having a concavo-convex pattern formed on its surface to dry the substrate.

JP 2012-243869 A

The present disclosure provides a substrate processing method and a substrate processing apparatus that are effective in suppressing pattern collapse of a concavo-convex pattern.

A substrate processing method according to an aspect of the present disclosure is to replace a liquid in a concave portion of a substrate having a concave-convex pattern on a surface with a reinforcing material in a solid state, and to reinforce while maintaining the reinforcing material in a solid state. Subjecting the substrate to a molecular weight reduction treatment for reducing the number of bonds between molecules contained in the material.

According to the present disclosure, there are provided a substrate processing method and a substrate processing apparatus which are effective in suppressing pattern collapse of a concavo-convex pattern.

FIG. 1 is a schematic diagram illustrating a schematic configuration of a substrate processing system. FIG. 2 is a schematic diagram illustrating the internal configuration of the coating and developing apparatus. FIG. 3 is a schematic view illustrating the configuration of the developing unit. FIG. 4 is a schematic view illustrating the configuration of the irradiation unit. FIG. 5 is a schematic diagram illustrating the configuration of the plasma processing apparatus. FIG. 6 is a block diagram illustrating the functional configuration of the control device. FIG. 7 is a block diagram illustrating a hardware configuration of the control device. FIG. 8 is a flowchart showing an example of the development processing procedure. FIG. 9A to FIG. 9D are schematic diagrams for explaining the inside of the concave portion in the development processing procedure. FIG. 10: is a figure which shows an example of the chemical formula of the polymer contained in a reinforcement material.

Various exemplary embodiments are described below. In the description, the same elements or elements having the same function will be denoted by the same reference symbols, without redundant description.

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

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

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

The processing module 11 includes a coating unit U1, a heat treatment unit U2, and a transfer device A3 that transfers a wafer W to these units. The processing module 11 forms a lower layer film on the surface of the wafer W by the coating unit U1 and the heat treatment unit U2. The coating unit U1 coats the processing liquid for forming the lower layer film on the wafer W. The heat treatment unit U2 performs various heat treatments associated with the formation of the lower layer film.

The processing module 12 includes a coating unit U1, a heat treatment unit U2, and a transfer device A3 that transfers a wafer W to these units. The processing module 12 forms a resist film on the lower layer film by the coating unit U1 and the heat treatment unit U2. The coating unit U1 coats a resist as a processing liquid for forming a resist film on the lower layer film. The heat treatment 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.

The processing module 13 includes a coating unit U1, a heat treatment unit U2, and a transfer device A3 that transfers a wafer W to these units. The processing module 13 forms an upper layer film on the resist film by the coating unit U1 and the heat treatment unit U2. The coating unit U1 coats the processing liquid for forming the upper layer film on the resist film. The heat treatment unit U2 performs various heat treatments associated with the formation of the upper layer film.

The processing module 14 includes a developing unit U3, a heat treatment unit U4, an irradiation unit U5, and a transfer device A3 that transfers the wafer W to these units. The processing module 14 develops the resist film after exposure by the developing unit U3, the heat treatment unit U4, and the irradiation unit U5. The developing unit U3 partially removes the resist film by applying (supplying) a developing solution onto the exposed surface of the wafer W. In other words, the developing unit U3 forms a resist pattern, which is an uneven pattern, on the surface of the wafer W. The developing unit U3 supplies the rinse liquid to the surface of the wafer W in order to wash away the developing liquid. Further, the developing unit U3 replaces the rinse liquid in the concave portion of the resist pattern with the processing liquid, and then forms the reinforcing material in the concave portion (see FIG. 9B). The heat treatment unit U4 performs various heat treatments associated with the development processing. Specific examples of the heat treatment associated with the development treatment include a heat treatment before the development treatment (PEB: Post Exposure Bake) and a heat treatment after the development treatment (PB: Post Bake). The irradiation unit U5 has a function of irradiating the surface of the wafer W with energy rays, and performs a part of the process for removing the rinse liquid.

A shelf unit U10 is provided on the carrier block 4 side in the processing block 5. The shelf unit U10 is divided into a plurality of 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 moves the wafer W up and down between the cells of the shelf unit U10.

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.

The interface block 6 transfers the wafer 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 device 3. The transfer device A8 transfers the wafer W placed on the shelf unit U11 to the exposure device 3. The transfer device A8 receives the wafer W from the exposure device 3 and returns it to the shelf unit U11.

(Development unit)
Subsequently, an example of the developing unit U3 will be described with reference to FIG. As shown in FIG. 3, the developing unit U3 includes a rotation holding unit 20 and three liquid supply units 30a, 30b, 30c.

The rotation holding unit 20 has a rotation drive unit 21, a shaft 22, and a holding unit 23. The rotation drive unit 21 operates based on an operation signal from the control device 100 to rotate the shaft 22. The rotation drive unit 21 incorporates, for example, an electric motor as a power source. The holding portion 23 is provided at the tip of the shaft 22. The wafer W is placed on the holding unit 23. The holding unit 23 holds the wafer W substantially horizontally, for example, by suction. That is, the rotation holding unit 20 rotates the wafer W around a central axis (rotation axis) perpendicular to the front surface Wa of the wafer W in a state where the wafer W is substantially horizontal. In the example of FIG. 3, the rotation holding unit 20 rotates the wafer W counterclockwise as viewed from above at a predetermined rotation speed.

The liquid supply unit 30a supplies the developing liquid L1 to the front surface Wa of the wafer W. The developing solution L1 is a chemical solution for developing the resist film R to form a resist pattern. For example, by supplying the developing solution L1 to the resist film R, the portion of the resist film R irradiated with the energy beam for exposure reacts and the portion is removed. The liquid supply unit 30b supplies the rinse liquid L2 to the front 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 that can wash away the developing liquid. For example, the rinse liquid L2 may be water (pure water). The liquid supply unit 30a and the liquid supply unit 30b form a development processing unit that performs a development process on the resist film R.

The liquid supply unit 30c (replacement processing unit) supplies the processing liquid L3 to the front surface Wa of the wafer W. The treatment liquid L3 is a chemical liquid for forming a reinforcing material in the concave portion of the resist pattern. The treatment liquid L3 may be a chemical liquid that can be supplied to the wafer W in a liquid state and that is dried and solidified by a predetermined treatment (for example, rotation of the wafer W). For example, the treatment liquid L3 may be a chemical liquid in which a polymer is dissolved in a solvent. The polymer may contain at least one of methyl polyacrylate, polymethacrylic acid, polyvinyl alcohol, an ultraviolet curable resin (UV curable resin), and polymethylmethacrylate (PMMA). If polymethyl acrylate, polymethacrylic acid, or polyvinyl alcohol is used, water may be used as the solvent. When polymethylmethacrylate is used, the solvent is 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.

The liquid supply units 30a, 30b, 30c each include a liquid source 31, a valve 33, a nozzle 34, and a pipe 35. The liquid sources 31 of the liquid supply units 30a, 30b, 30c respectively supply the chemical liquid to the nozzle 34 via the valve 33 and the pipe 35. The nozzles 34 of the liquid supply units 30a, 30b, and 30c are arranged above the wafer W so that the ejection ports face the front surface Wa of the wafer W. The nozzle 34 ejects 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 reciprocates the nozzle 34 in the horizontal direction.

Although the detailed configuration is omitted, the heat treatment unit U4 has a configuration capable of performing heat treatment on the wafer W. For example, the thermal processing unit U4 includes an openable/closable chamber that forms a processing space for performing thermal processing, and a heating plate that is housed in the chamber and that heats the wafer W while supporting it. The chamber is opened and closed according to an instruction from the control device 100. The hot plate has a built-in heater, for example, and the temperature of the hot plate is controlled by the control device 100.

(Irradiation unit)
Subsequently, an example of the irradiation unit U5 will be described with reference to FIG. As shown in FIG. 4, the irradiation unit U5 includes an irradiation unit 42 (molecular weight reduction processing unit).

The irradiation unit 42 irradiates the surface Wa (reinforcing material) of the wafer W with energy rays. As the energy rays, for example, electron rays or electromagnetic waves may be used. The irradiation unit 42 may irradiate with any energy ray as long as the irradiation can reduce the number of intermolecular bonds contained in the reinforcing material. For example, the irradiation unit 42 may irradiate an energy ray that can reduce the degree of polymerization of the polymer contained in the reinforcing material. Specific examples of the energy rays include ultraviolet rays having a wavelength of 100 nm to 400 nm. The wavelength of the energy rays may be 170 nm to 180 nm. The wavelength of the energy ray is not limited to the above value, and the wavelength of the energy ray to be used may be selected according to the type of the reinforcing material, for example.

The irradiation unit U5 causes the irradiation section 42 to emit ultraviolet rays from above to the wafer W supported horizontally. For example, the irradiation unit 42 has a light source that emits ultraviolet rays. Specific examples of the light source include a krypton fluoride excimer light source that emits an ultraviolet ray having a wavelength of 172 nm, an argon fluoride excimer light source that emits an ultraviolet ray having a wavelength of 193 nm, and a krypton chloride excimer light source that emits an ultraviolet ray having a wavelength of 222 nm. The irradiation unit 42 is configured to emit the energy rays emitted from the light source downward toward the wafer W.

(Plasma processing device)
Subsequently, an example of the plasma processing apparatus 10 will be described with reference to FIG. The plasma processing apparatus 10 performs plasma processing on the wafer W using the resist pattern as a mask. In other words, the plasma processing apparatus 10 etches a part of the wafer W by performing etching processing using plasma on the wafer W. Further, the plasma processing apparatus 10 may perform an etching process using plasma on the reinforcing material formed in the concave portion of the resist pattern. In the present specification, “to perform plasma treatment” or “to perform etching treatment using plasma” means exposing at least the front surface Wa of the wafer W to a gas in a plasma state for a predetermined time.

The plasma processing apparatus 10 is connected to the coating/developing apparatus 2 via a transport mechanism 19 (see FIG. 2). The transfer mechanism 19 transfers the wafer W between the coating/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 unit 60, a power supply unit 80, and an exhaust unit 90. The processing unit 60 includes a processing container 68, an electrostatic chuck 61, a susceptor 63, a support base 64, and an upper electrode 73.

The processing container 68 has conductivity and is formed in a substantially cylindrical shape. A ground wire 69 is electrically connected to the processing container 68, and the processing container 68 is grounded. The electrostatic chuck 61 and the susceptor 63 are provided in the processing container 68 and support the wafer W to be processed. The electrostatic chuck 61 is a substantially disk-shaped member, and is formed, for example, by sandwiching an electrostatic chuck electrode 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 of a metal such as aluminum into a substantially disc shape. A support base 64 is provided at the bottom of the processing container 68, and the susceptor 63 is supported on the upper surface of the support base 64. Electrodes (not shown) are provided inside the electrostatic chuck 61, and the wafer W is adsorbed and held on the electrostatic chuck 61 by the electrostatic force generated by applying a DC voltage to the electrode. A coolant flow path (not shown) through which the coolant flows is provided inside the support base 64, and the temperature of the wafer W held by the electrostatic chuck 61 is controlled by controlling the temperature of the coolant. R.

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

Further, a high frequency power source 83 is electrically connected to the susceptor 63 via a matching unit 84 in order to draw ions into the wafer W by applying a bias to the wafer W. The high frequency power supply 83 is configured to output high frequency power having a frequency of 400 kHz to 13.56 MHz, for example. The matching device 84, like the matching device 82, 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.

An upper electrode 73 is arranged on the upper portion of the processing container 68. The upper electrode 73 is provided so as to face the susceptor 63. The upper electrode 73 is supported on the upper portion of the processing container 68 and is grounded via the processing container 68. A gas diffusion chamber 76 formed in a substantially disc shape is formed in the central portion inside the upper electrode 73. In the lower part of the upper electrode 73, a plurality of gas discharge holes 77 for supplying the processing gas into the processing container 68 are formed so as to penetrate the lower part of the upper electrode 73.

A gas supply pipe 78 is connected to the gas diffusion chamber 76. A gas supply source 79 is connected to the gas supply pipe 78 as shown in FIG. 5, and the gas supply source 79 supplies the 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 container 68 through the gas discharge hole 77. The processing gas supplied from the gas supply source 79 may include an inert gas. A rare gas (eg, argon gas) or a nitrogen gas may be used as the inert gas.

An exhaust unit 90 is arranged below the processing container 68. The exhaust unit 90 includes an exhaust port 91, an exhaust chamber 92, an exhaust pipe 93, and an exhaust device 94. An exhaust port 91 is provided on the bottom surface of the processing container 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. Therefore, by driving the exhaust device 94 (for example, an exhaust pump), the inside of the processing container 68 can be exhausted through the exhaust port 91 and the inside of the processing container 68 can be depressurized to a predetermined vacuum degree.

(Control device)
Subsequently, a specific configuration of the control device 100 will be illustrated. The controller 100 controls the substrate processing system 1 partially or wholly. The control device 100 replaces the liquid in the recess 202 of the wafer W having the concavo-convex pattern formed on the surface Wa with the reinforcing material 220a in the solid state, and maintains the reinforcing material 220a in the solid state while the reinforcing material 220a is maintained. Is performed on the wafer W to reduce the number of intermolecular bonds contained in the wafer W.

As shown in FIG. 6, the control device 100 has a functional configuration (hereinafter referred to as “functional module”), a heat treatment control unit 101, a development control unit 102, an irradiation control unit 103, and an etching control unit. And 104. The heat treatment control unit 101 controls the heat treatment unit U4. The development control unit 102 controls the valve 33 and the rotation drive unit 21 of each of the liquid supply units 30a, 30b, 30c in the development unit U3. The irradiation 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 apparatus 10. Details of the processing contents of each unit will be described later.

The control device 100 is composed of one or a plurality of control computers. For example, the controller 100 has the 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 a substrate processing procedure described later. 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 calculation result by the processor 121. The processor 121 configures each functional module described above by executing the above program in cooperation with the memory 122. The input/output port 124 inputs/outputs an electric signal to/from a member to be controlled according to a command from the processor 121.

When the control device 100 is composed of a plurality of control computers, each of the heat treatment control unit 101, the development control unit 102, the irradiation control unit 103, and the etching control unit 104 may be realized by an individual control computer. .. Alternatively, each of these functional modules may be realized by a combination of two or more control computers. In these cases, the plurality of control computers may execute the substrate processing procedure described later in cooperation with each other while being communicably connected to each other. Note that the hardware configuration of the control device 100 is not necessarily limited to one that configures each functional module 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) in which the logic circuit is integrated.

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

Next, the control device 100 controls the transfer device A3 so as to transfer the wafer W of the shelf unit U10 to the coating unit U1 and the heat treatment unit U2 in the processing module 11. Further, the control device 100 controls the coating unit U1 and the heat treatment unit U2 so as to form the lower layer film on the front surface Wa of the wafer W. After that, the control device 100 controls the transfer device A3 so as to return the wafer W on which the lower layer film is formed to the shelf unit U10, and controls the transfer device A7 so as to arrange the wafer W in the cell for the processing module 12. ..

Next, the control device 100 controls the transfer device A3 to transfer the wafer W of the shelf unit U10 to the coating unit U1 and the heat treatment unit U2 in the processing module 12. Further, the control device 100 controls the coating unit U1 and the heat treatment unit U2 so as to form the resist film R on the lower layer film of the wafer W. After that, the control device 100 controls the transfer device A3 so as to return the wafer W to the shelf unit U10, and controls the transfer device A7 so as to arrange the wafer W in the cell for the processing module 13.

Next, the control device 100 controls the transfer device A3 to transfer the wafer W of the shelf unit U10 to each unit in the processing module 13. Further, the control device 100 controls the coating unit U1 and the heat treatment unit U2 so as to form an upper layer film on the resist film R of the wafer W. After that, the control device 100 controls the transfer device A3 to transfer the wafer W to the shelf unit U11.

Next, the control device 100 controls the transfer device A8 so that the wafer W stored in the shelf unit U11 is sent to the exposure device 3. Then, in the exposure apparatus 3, the resist film R formed on the wafer W is exposed. After that, the control device 100 receives the wafer W that has been subjected to the exposure processing from the exposure device 3, and controls the transfer device A8 so as to arrange the wafer W in the cell for the processing module 14 in the shelf unit U11.

Next, the control device 100 controls the transfer device A3 so as to transfer the wafer W of the shelf unit U11 to the thermal processing unit U4 of the processing module 14. Then, the control device 100 performs control so as to execute a heat treatment accompanying the development processing and a processing procedure including the development processing (hereinafter, referred to as “development processing procedure”). As a result, a resist pattern is formed on the front surface Wa of the wafer W. Details of the development processing procedure will be described later. After that, the control device 100 controls the plasma processing device 10 so as to perform the etching process using plasma on the wafer W using the resist pattern as a mask. With the above, the substrate processing including the coating/developing processing is completed.

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

Next, the control device 100 executes step S02. In step S02, the development controller 102 controls the development unit U3 to supply the developing solution 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 so that the wafer W rotates at a predetermined rotation speed, and opens the valve 33 of the liquid supply unit 30a to open the developer L1 from the nozzle 34. Discharge. As a result, the resist pattern 200 having the convex portions 201 and the concave portions 202 is formed on the front surface Wa of the wafer W (see FIG. 9A). The part of the resist film R that has not been removed (for example, the part that was not exposed during the exposure process) becomes the convex portion 201, and the part of the resist film R that has been removed (between the adjacent convex portions 201). The space) becomes the recess 202.

Next, the control device 100 executes step S03. In step S03, the development control unit 102 controls the development unit U3 so as 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 so that the wafer W rotates at a predetermined rotation speed, and opens the valve 33 of the liquid supply unit 30b to open the rinse liquid L2 from the nozzle 34. Discharge. As shown in FIG. 9A, the development control unit 102 rotates the wafer W so that a part of the discharged rinse liquid L2 (rinse liquid 210) remains on the front surface Wa of the wafer W. 21 or the rotation of the wafer W is stopped. At this time, the recess 202 may be entirely filled with the rinse liquid 210 as in the example of FIG. Note that the height of the rinse liquid 210 is not limited to the example of FIG. 9A, and it is sufficient that at least a part of the recess 202 is filled with the rinse liquid 210.

Next, the control device 100 executes step S04. In step S04, the development control unit 102 controls the development unit U3 so as to supply the processing liquid L3 to the wafer W on which the rinse liquid 210 remains on the front surface Wa. For example, the development control unit 102 controls the rotation driving unit 21 so that the wafer W rotates at a predetermined rotation speed, and opens the valve 33 of the liquid supply unit 30c to open the processing liquid L3 from the nozzle 34. Discharge. 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 the liquid (a part of the treatment liquid L3). It is sufficient that at least a part of the recess 202 is filled with the processing liquid L3.

Next, the control device 100 executes step S05. In step S05, the development control unit 102 controls the development unit U3 so as to dry the processing liquid L3 filling the recess 202. For example, the development control unit 102 controls the rotation driving unit 21 to rotate the wafer W until the processing liquid L3 that is in the liquid state becomes the solid state. As a result, as shown in FIG. 9B, the solid reinforcing material 220a is formed in the recess 202. For example, when the treatment liquid L3 contains a polymer, by rotating and drying the wafer W, many polymers dispersed in the treatment liquid L3 are entangled with each other. As a result, the solid reinforcing material 220a is formed in the recess 202. In this case, the liquid supply unit 30c of the developing unit U3 and the rotation holding unit 20 form a replacement processing unit.

By performing steps S04 and S05, the rinse liquid 210 in the recess 202 is replaced with the reinforcing material 220a in the solid state. At this time, as in the example of FIG. 9B, the reinforcing material 220a may be formed in the recess 202 so as to fill almost all the space in the recess 202. As an example, the reinforcing material 220a may be formed in the concave portion 202 such that the height of the reinforcing material 220a is substantially equal to the height of the convex portion 201. The height of the reinforcing material 220a is not limited to the example shown in FIG. 9B, and at least a part of the recess 202 may be filled with the reinforcing material 220a. Further, the reinforcing material 220a may be formed with a height exceeding the height of the convex portion 201 (the depth of the concave portion 202). Then, the control device 100 controls the transfer device A3 so as to transfer the wafer W having the reinforcing material 220a formed in the recess 202 to the irradiation unit U5.

Next, the control device 100 executes step S06. In step S06, the irradiation control unit 103 controls the irradiation unit U5 to irradiate the reinforcing material 220a with energy rays. For example, the irradiation control unit 103 controls the irradiation unit 42 to irradiate the entire front surface Wa of the wafer W with energy rays. The type of energy ray may be determined by the type of treatment liquid L3 (the type of polymer contained in the reinforcing material 220a). By irradiating the reinforcing material 220a with energy rays, the number of intermolecular bonds contained in the reinforcing material 220a is reduced while the reinforcing material 220a is maintained in a solid state (without the reinforcing material 220a being in a liquid state). To do. For example, when 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 is decomposed into a plurality of polymers having a polymerization degree (for example, several tens to several hundreds) lower than the polymerization degree (for example, several thousands to tens of thousands) of the polymer. Good. In addition, each polymer contained in the reinforcing material 220a may be decomposed into a plurality of monomers, dimers, or trimers each having 1, 2, or 3 structural units.

In this way, the irradiation control unit 103 irradiates the reinforcing material 220a with energy rays to maintain the reinforcing material 220a in a solid state, and at the same time, the number of intermolecular bonds contained in the reinforcing material 220a (for example, the polymerization degree of the polymer) 2) is applied to the wafer W. As a result, as shown in FIG. 9C, the reinforcing material 220a (hereinafter referred to as "reinforcing material 220b") that has been subjected to the molecular weight reduction treatment is formed in the recess 202. The irradiation controller 103 may reduce the number of intermolecular bonds contained in the reinforcing material 220a to a level where the reinforcing material 220b is more easily sublimated than the resist pattern 200 when performing the molecular weight reduction process.

Here, "sublimation" in this specification means that the reinforcing material 220b transits from a solid state to a gas state without passing through a liquid state. This "sublimation" includes not only the state change from the solid state to the gas state (change from the solid phase to the gas phase) but also the transition of the reinforcing material 220b from the solid state to the gas state with a chemical change. For example, transitioning from a solid state to a gas state with a chemical change includes etching the reinforcing material 220b by performing an etching process using plasma on the reinforcing material 220b. The "easiness of sublimation" here means the ease of sublimation (for example, the amount of sublimation per unit time) under the environment for sublimating the reinforcing material 220b. For example, the state in which the reinforcing material 220b is more easily sublimated than the resist pattern 200 means that the reinforcing material 220b is etched more than the resist pattern 200 under the condition of the plasma treatment for etching the reinforcing material 220b. is there.

FIG. 10 exemplifies how the number of bonds (degree of polymerization) in the polymer changes when the polymer containing polymethyl methacrylate is contained in the treatment liquid L3. The degree of polymerization of each polymer contained in the reinforcing material 220a is indicated by "L+M+N... "(L, M, N are positive integers). By irradiating the reinforcing material 220a with energy rays in the irradiation unit U5, some of the “C—CH2” bonds, which are the main chains connecting the monomers, are broken. As a result, in the reinforcing material 220b, a compound having a monomer constituent unit of "L" (for example, a polymer having a degree of polymerization of "L"), a compound having a monomer constituent unit of "M", and a monomer constituent unit A compound or the like that is "N" is formed. For example, when a plurality of polymers having a reduced degree of polymerization are formed by irradiation with energy rays, the reduced degree of polymerization changes the substance from a stable state to a property that is more easily sublimated.

Next, the control device 100 controls the transfer device A3 to transfer the wafer W on which the reinforcing material 220b is 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 so that the wafer W, which has been subjected to the development processing by the supply of the developing solution L1, is heat-treated at a predetermined temperature for a predetermined time. Then, the control device 100 controls the transfer device A3 so as to return the wafer W that has been subjected to the heat treatment after development to the shelf unit U10, and returns the wafer W into the carrier C by the transfer device A7 and the transfer device A1. To control. After that, the controller 100 controls the transfer mechanism 19 to transfer the wafer W in the carrier C to the plasma processing apparatus 10.

Next, the control device 100 executes step S08. In step S08, the etching control unit 104 controls the plasma processing apparatus 10 so that the reinforcing material 220b is subjected to etching processing using plasma. In step S08, first, the wafer W is placed on the electrostatic chuck 61 so that the front surface Wa on which the resist pattern 200 is formed faces upward. Then, the etching control unit 104 controls the plasma processing apparatus 10 so that the processing gas for plasma generation is supplied from the gas supply source 79 into the processing container 68. The processing gas may be determined according to the type of polymer contained in the processing liquid L3, for example. After that, the etching control unit 104 controls the power supply unit 80 so that the high frequency power supply 81 and the high frequency power supply 83 continuously apply the high frequency power to the susceptor 63 that is the lower electrode. Thereby, a high frequency electric field is formed between the upper electrode 73 and the electrostatic chuck 61.

By forming the high frequency electric field, plasma of the processing gas is generated in the processing container 68, and the reinforcing material 220b is etched by the plasma. At this time, since the reinforcing material 220b is formed by subjecting the reinforcing material 220a to the low molecular weight treatment, the reinforcing material 220b is more easily sublimated than the resist pattern 200. Therefore, the resist pattern 200 (the convex portion 201) is not etched, but the reinforcing material 220b is etched. As a result, as shown in FIG. 9D, the reinforcing material 220b in the recess 202 is sublimated and removed. As described above, the plasma processing apparatus 10 constitutes a removing unit that sublimates and removes the reinforcing material (reinforcing material 220b) that has been subjected to the molecular weight reduction treatment. With the above, a series of development processing procedures is completed.

By performing the processing in steps S03 to S08, the rinse liquid 210 is removed from the front surface Wa of the wafer W. In this development processing procedure, the rinse liquid 210 discharged onto the front surface Wa of the wafer W is once replaced by the reinforcing material 220a (reinforcing material 220b), and the reinforcing material 220b is removed (sublimed) by etching, so that the wafer The rinse liquid 210 is removed from the surface Wa of the W. Looking at the state inside the concave portion 202, after the liquid (rinse liquid 210) enters the solid state (reinforcing materials 220a, 220b), the solid state enters and then gas (atmosphere, etc.) enters. It has transitioned to the closed state.

[Effect of Embodiment]
In the substrate processing method according to the present embodiment described above, the liquid in the recess 202 of the wafer W having the concavo-convex pattern formed on the front surface Wa is replaced with the solid reinforcing material 220a, and the reinforcing material 220a is solid. While maintaining the above value, the wafer W is subjected to a molecular weight reduction treatment for reducing the number of intermolecular bonds contained in the reinforcing material 220a.

The substrate processing system 1 maintains the reinforcing material 220a in a solid state while maintaining the reinforcing material 220a in a solid state, and a replacement processing section that replaces the liquid in the concave portion 202 of the wafer W in which the uneven pattern is formed on the surface Wa with the solid reinforcing material 220a. The wafer W is subjected to a molecular weight reduction treatment for reducing the number of intermolecular bonds contained in the reinforcing material 220a.

In the substrate processing method and the substrate processing system 1, the liquid in the concave portions 202 of the concavo-convex pattern is replaced with the solid reinforcing material 220a, and the reinforcing material 220a is subjected to the low differentiation treatment. By lowering the molecular weight of the reinforcing material 220a, a wafer W capable of removing the reinforcing material 220a (reinforcing material 220b) while leaving the uneven pattern is formed. Since the substance is removed from the inside of the recess 202 by removing the reinforcing material 220b, the liquid such as the rinse liquid 210 is removed from the recess 202.

When removing (drying) the liquid such as the rinse liquid 210 from the inside of the recess, the wafer W is rotated at a predetermined rotation speed and the liquid is shaken off by the centrifugal force to be removed. In this case, the inside of the recess 202 is changed from the state in which the liquid (rinse liquid) is contained to the state in which the gas (atmosphere) is contained. In this transition process, liquid may remain in some of the plurality of recesses 202, so that the pattern (projection 201) may collapse due to surface tension. In the substrate processing method and the substrate processing system 1 of the present embodiment, since the transition from the liquid-containing state to the gas-containing state is not performed in the recess 202, the liquid remains in some recesses of the uneven pattern. It is difficult for pattern collapse due to That is, the substrate processing method and the substrate processing system 1 are effective in suppressing pattern collapse.

In the above embodiment, when the molecular weight reduction treatment is performed, the number of intermolecular bonds in the reinforcing material 220a is reduced to a level where the reinforcing material 220b is more likely to sublime than the uneven pattern. In this case, a substrate is formed in which the reinforcing material 220b can be removed more reliably while leaving the uneven pattern.

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 the molecular weight reduction treatment. Since the reinforcing material 220b is subjected to the molecular weight reduction treatment, it is more easily sublimated than the uneven pattern. Therefore, the reinforcing material 220b can be sublimated and removed while leaving the uneven pattern. In this method, when removing (drying) the liquid in the recess 202, the interior of the recess 202 transits to a liquid, a solid, and a gas in this order, so that gas enters from the state where the liquid enters the recess 202. It is possible to suppress the pattern collapse caused by the transition to the state.

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 the molecular weight reduction treatment, the reinforcing material 220b in the solid state can be sublimated by the etching treatment using plasma while leaving the uneven pattern. The plasma etching apparatus 10 performs the etching process using plasma on the reinforcing material 220b. For this reason, the plasma processing apparatus 10 can be utilized not only for the etching process for the wafer W using the resist pattern 200 as a mask but also for the etching process for the reinforcing material 220b, so that the configuration of the substrate processing system 1 can be simplified.

In the above embodiment, replacement with the reinforcing material 220a is performed by supplying the processing liquid L3 to the front surface Wa of the wafer W, replacing the liquid in the recess 202 with the processing liquid L3, and drying the processing liquid L3. Forming a reinforcing material 220a in the recess 202. In this case, it is easy to change the state of the recess 202 from the state of containing the liquid to the state of containing the solid.

In the above embodiment, the uneven pattern is the resist pattern 200 formed by developing the resist film R that has been subjected to the exposure process. In this case, when the developing solution L1 for developing is washed away with the rinse solution L2, pattern collapse caused by the removal of the rinse solution L2 is suppressed.

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, an 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. As the degree of polymerization decreases, the substance becomes in a state in which it easily reacts, so that the reinforcing material 220a can be reacted (sublimated) and removed under the condition that the uneven pattern does not react.

It is possible to supply a processing solution containing a polymer having a low degree of polymerization and easily reacting, but such a processing solution is in an unstable state, and it is difficult to handle the processing solution before and after the supply. is there. In the above-described embodiment, by decomposing a polymer having a high degree of polymerization (for example, a degree of polymerization of thousands to tens of thousands) into a polymer having a low degree of polymerization (for example, a degree of polymerization of tens to hundreds), Easy to handle. Further, when the treatment liquid is dried, the reinforcing material 220a in a solid state is formed by entanglement of the polymers having a high degree of polymerization, so that the substance in the recess can be easily changed from the liquid to the solid. Depending on the type of substance contained in the treatment liquid, a thin film may be formed on the surface of the convex portion 201, and the roughness of the resist pattern 200 may be reduced.

(Modification)
Although the embodiments have been described above, the present disclosure is not necessarily limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

The substrate processing system 1 includes a replacement processing unit that replaces the liquid in the recess 202 with a solid-state reinforcing material, a low-molecularization processing unit that performs a low-molecularization processing on the reinforcing material, and a control device that can control these. It can be anything. In the substrate processing system 1, the plasma processing apparatus 10 may be provided inside the coating/developing apparatus 2.

The processing module 12 may form a resist film containing a cross-linking agent that promotes cross-linking in response to the irradiation of energy rays in the irradiation unit U5. In this case, in step S06, when the entire surface Wa of the wafer W is irradiated with energy rays, the reinforcing material 220a is subjected to the molecular weight reduction treatment and the crosslinking reaction is promoted in the convex portion 201 formed of the resist film. Then, the convex portion 201 is hardened.

In the substrate processing method according to this modification, performing the molecular weight reduction processing includes irradiating the reinforcing material 220a with energy rays. The resist film contains a crosslinking agent that promotes crosslinking in response to irradiation with energy rays. In this case, the convex portion 201 is hardened with the irradiation of the energy ray for the molecular weight reduction treatment. Therefore, the selection ratio (contrast ratio) between the reinforcing material 220b and the resist pattern 200 is increased, and it is easy to remove the reinforcing material 220b in the recess 202 while leaving the resist pattern 200. Further, the irradiation of energy rays for the treatment of lowering the molecular weight can be effectively used for curing the convex portion 201.

In the process of step S06, the control device 100 may apply the thermal energy to the reinforcing material 220a in addition to the irradiation of energy rays, thereby performing the molecular weight reduction processing on the reinforcing material 220a. For example, the irradiation control unit 103 may apply heat energy to the reinforcing material 220a by placing the wafer W on the heating plate 43 described below and heating the wafer W in the irradiation unit U5. In this case, the irradiation unit U5 may further include a heating unit 41 (molecular weight reduction unit) (see FIG. 4).

The heating unit 41 heats the reinforcing material 220a formed in the recess 202 of the resist pattern 200. 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 for supporting and heating the wafer W arranged horizontally. For example, the heating plate 43 incorporates a plurality of heaters as a heat source. A specific example of the heater is a heating wire type heater.

The elevating mechanism 44 elevates and lowers the wafer W on the heating plate 43. For example, the elevating mechanism 44 has a plurality of (for example, three) elevating pins 45 and an elevating drive unit 46. The plurality of lift pins 45 project upward so as to penetrate the heating plate 43. The elevating drive unit 46 elevates and lowers the plurality of elevating pins 45, and causes the tip of the elevating pins 45 to project and retract in the upper portion of the heating plate 43. As a result, the wafer W can be moved up and down on the heating plate 43.

The irradiation control unit 103 may control the heating unit 41 so that the heating plate 43 heats the wafer W with the lifting pins 45 lowered by the lifting drive unit 46. Further, the irradiation control unit 103 controls the irradiation unit 42 so as to irradiate the front surface Wa with energy rays in a state where the wafer W is raised by driving the elevating drive unit 46 (a state in which the wafer W is brought close to the irradiation unit 42). You may. The heating unit 41 and the irradiation unit 42 do not necessarily have to be configured as one unit, and may be configured as independent units.

Alternatively, the control device 100 (irradiation control unit 103) may apply the thermal energy to the wafer W, instead of irradiating the wafer W with the energy rays, to perform the molecular weight reduction process on the reinforcing material 220a. .. In this case, the irradiation unit 42 may be omitted in the irradiation unit U5. Alternatively, the control device 100 may perform the molecular weight reduction process by applying heat energy to the reinforcing material 220a in the heat treatment unit U4 instead of the irradiation unit U5.

When the thermal energy is applied to the reinforcing material 220a containing the polymer containing polymethylmethacrylate, a part of the "C-CH2" bond is broken, as in the case of irradiating with energy rays, so that the intermolecular bond is released. The number of bonds is reduced (see FIG. 10). In this way, the formation of a plurality of compounds in which the number of intermolecular bonds is reduced by the application of heat energy changes from a stable state of the substance to a property of being more easily sublimated.

The height of the reinforcing members 220a and 220b formed in the recess 202 may be substantially the same as that of the resist pattern 200 (projection 201) or may be lower than that of the projection 201. The height of the reinforcing members 220a and 220b may be higher than that of the convex portion 201. In this case, the reinforcing members 220 a (reinforcing members 220 b) located inside the concave portions 202 may be connected to each other above the convex portions 201 by a film-like reinforcing material. In this way, the reinforcing materials 220a and 220b may fill at least a part of the recess 202.

In the processing of step S08, the control device 100 places the wafer W on which the reinforcing material 220b is formed in the processing container 68 of the plasma processing apparatus 10 in place of the etching processing using plasma, so that the reinforcing material 220b. May be sublimated (evaporated). That is, the control device 100 may perform the process of sublimating the reinforcing material 220b by placing the wafer W in the depressurized space. Alternatively, the control device 100 may perform sublimation of a part of the reinforcing material 220b by placing the wafer W in the depressurized space (inside the processing container 68) of the plasma processing device 10 and perform an etching process using plasma. The remaining portion of the reinforcing material 220b may be sublimated. Even in these cases, since the plasma processing apparatus 10 can be utilized 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, the configuration of the substrate processing system 1 is simplified. Is planned.

The substrate processing system 1 may include, instead of the plasma processing apparatus 10, a decompression unit (removal section) capable of forming a decompressed space (a space that is substantially in a vacuum state). The reinforcing material 220b may be removed in the unit. The decompression unit may be provided in the coating/developing device 2. In this case, the coating/developing apparatus 2 may perform all of the above-described development processing procedures. When sublimating the reinforcing material 220b in the depressurized space, the control device 100 performs the molecular weight reduction process in step S06 to reinforce the wafer W when the wafer W is placed in the depressurized space after the molecular weight reduction process. The number of intermolecular bonds (for example, the degree of polymer polymerization) may be reduced so that the material 220b becomes more sublimated.

In the substrate processing methods according to these modifications, sublimating and removing the reinforcing material 220b includes placing the wafer W in a depressurized space to sublimate the reinforcing material 220b. Since the reinforcing material 220b has been subjected to a molecular weight reduction treatment, by placing the wafer W in a depressurized space, it is possible to evaporate the solid reinforcing material 220b without leaving the liquid state while leaving the uneven pattern. You can

The developing unit U3 does not dry the rinse liquid in the concave portion 202 (without emptying the concave portion 202) when the rinse liquid in the concave portion 202 is replaced with the solid reinforcing material. Should be replaced with For example, the developing unit U3 may supply a powdery substance containing a polymer to the rinse liquid on the surface Wa to precipitate the solid matter and then remove the rinse liquid. Alternatively, the developing unit U3 may solidify the rinse liquid by dissolving a powdery substance containing a polymer in the rinse liquid on the surface Wa and drying the rinse liquid in which the substance is dissolved.

The substrate to be processed is not limited to the semiconductor wafer, and may be, for example, a glass substrate, a mask substrate, an FPD (Flat Panel Display), or the like.

DESCRIPTION OF SYMBOLS 1... Substrate processing system, 2... Coating/developing apparatus, U3... Developing unit, U5... Irradiation unit, 10... Plasma processing apparatus, 200... Resist pattern, 201... Convex part, 202... Recessed part, 220a, 220b... Reinforcing material, W... Wafer, Wa... Surface.

Claims (10)

Replacing the liquid in the concave portion of the substrate having the concave-convex pattern on the surface with a solid-state reinforcing material,
A method of treating a substrate, which comprises subjecting the substrate to a molecular weight reduction treatment for reducing the number of bonds between molecules contained in the reinforcing material while maintaining the reinforcing material in a solid state. The substrate processing method according to claim 1, wherein, when the molecular weight reduction treatment is performed, the number of intermolecular bonds in the reinforcing material is reduced to a level at which the reinforcing material is more likely to sublime than the uneven pattern. The substrate processing method according to claim 1, further comprising sublimating and removing the reinforcing material that has been subjected to the molecular weight reduction treatment. The substrate processing method according to claim 3, wherein the sublimation and removal of the reinforcing material includes sublimation of the reinforcing material by placing the substrate in a depressurized space. The substrate processing method according to claim 3, wherein sublimating and removing the reinforcing material includes subjecting the reinforcing material to an etching treatment using plasma. Replacing with the reinforcement is
Supplying a treatment liquid to the surface of the substrate to replace the liquid in the recess with the treatment liquid;
The substrate processing method according to claim 1, further comprising: drying the processing liquid to form the reinforcing material in the recess. The substrate processing method according to claim 1, wherein the concavo-convex pattern is a resist pattern formed by subjecting an exposed resist film to a developing process. Applying the low molecular weight treatment includes irradiating the reinforcing material with energy rays,
The substrate processing method according to claim 7, wherein the resist film contains a crosslinking agent that promotes crosslinking in response to the irradiation of the energy rays. 9. The reinforcing material includes a polymer containing at least one of polymethyl acrylate, polymethacrylic acid, polyvinyl alcohol, an ultraviolet curable resin, and polymethylmethacrylate. Substrate processing method. The liquid in the concave portion of the substrate having the concave-convex pattern formed on the surface, a substitution processing portion for replacing the solid state reinforcing material,
A substrate processing apparatus comprising: a molecular weight reduction unit that performs a molecular weight reduction treatment for reducing the number of intermolecular bonds contained in the reinforcing material on the substrate while maintaining the reinforcement material in a solid state.

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