Substrate processing method and processing agent for sublimation drying

Abstract

To achieve excellent drying performance, and dry a substrate satisfactorily while preventing a pattern from collapsing.SOLUTION: A substrate treatment method includes a liquid film forming step of supplying, to a surface of a substrate on which a pattern is formed, a treatment liquid obtained by liquefying a sublimation drying treatment agent in which a first sublimation substance and a second sublimation substance which are different from each other are mixed at an eutectic composition or a near-eutectic composition to form a liquid film of the treatment liquid on the surface of the substrate, a solidified film forming step of solidifying the liquid film of the treatment liquid to form a solidified film of the sublimation drying treatment agent, and a sublimation step of sublimating the solidified film to remove it from the surface of the substrate.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] This invention relates to a substrate processing method for drying a substrate having a pattern formed on its surface, using a sublimation drying processing agent containing a sublimable substance that undergoes a phase transition from solid to gas without passing through a liquid, and to a sublimation drying processing agent used in the substrate processing method. Substrates include semiconductor wafers, substrates for liquid crystal display devices, substrates for FPDs (Flat Panel Displays) such as organic EL (electroluminescence) display devices, substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, substrates for photomasks, ceramic substrates, substrates for solar cells, etc. [Background technology]

[0002] The manufacturing process of electronic components such as semiconductor devices and liquid crystal display devices includes a process of forming a pattern by repeatedly performing processes such as film formation and etching on the surface of a substrate. After the pattern is formed, a cleaning process using a chemical solution, a rinsing process using a rinsing solution, and a drying process are performed in this order. As the patterns become finer, the importance of the drying process is particularly increasing. In other words, a technique for suppressing or preventing the occurrence of pattern collapse during the drying process is becoming important. Therefore, as described in Patent Document 1, for example, a substrate processing method has been proposed in which a substrate is sublimated and dried using a processing solution in which camphor is dissolved in IPA (isopropyl alcohol). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-243869 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above conventional technology, a treatment liquid in which a sublimable substance (camphor) is dissolved in a solvent (IPA) is used as a treatment agent for sublimation drying. The solvent is then evaporated to deposit the sublimable substance on the surface of the substrate (solidified film formation process), but some of the solvent may remain in the solidified film formed on the surface of the substrate. As a result, the remaining solvent may cause the pattern to collapse.

[0005] The present invention has been made in consideration of the above problems, and has an object to provide a substrate processing method that has excellent drying performance and is capable of satisfactorily drying a substrate while preventing pattern collapse, and a sublimation drying processing agent that is suitable for the substrate processing method. [Means for solving the problem]

[0006] One aspect of the present invention is a substrate processing method, comprising: a liquid film forming step of supplying a processing liquid obtained by liquefying a processing agent for sublimation drying, the processing liquid being a mixture of a first sublimable substance and a second sublimable substance different from each other in a eutectic composition or a near-eutectic composition, to a surface of a substrate on which a pattern has been formed, to form a liquid film of the processing liquid on the surface of the substrate; a solidified film forming step of solidifying the liquid film of the processing liquid to form a solidified film of the processing agent for sublimation drying; and a sublimation step of sublimating the solidified film and removing it from the surface of the substrate. The first sublimable substance is camphor, the second sublimable substance is cyclohexanone oxime, and the weight percentage of the second sublimable substance in the treatment agent for sublimation drying is in the range of the weight percentage in the eutectic composition or more and 60% or less. It is characterized by the following.

[0007] Another aspect of the present invention is a sublimation drying treatment agent that is supplied in a liquid state to a surface of a substrate on which a pattern has been formed, and then solidified and sublimated in this order, thereby drying the surface of the substrate, the treatment agent being a mixture of a first sublimable substance and a second sublimable substance that are different from each other, with a eutectic composition or a near-eutectic composition, The first sublimable substance is camphor, the second sublimable substance is cyclohexanone oxime, and the weight percentage of the second sublimable substance in the treatment agent for sublimation drying is in the range of the weight percentage in the eutectic composition or more and 60% or less. It is characterized by the following. Effect of the Invention

[0008] The sublimation drying agent of the present invention is a mixture of a first sublimation material and a second sublimation material, which are different from each other, in a eutectic composition or a composition close to eutectic. Therefore, the problem of the solvent remaining on the solidified film, which was a problem in the prior art using a sublimation drying agent in which a sublimation material is dissolved in a solvent, does not occur. As a result, the collapse of the pattern on the surface of the substrate can be suppressed.

[0009] In addition, since the sublimation drying treatment agent is a mixture of two kinds of sublimation substances with a eutectic composition or a composition close to eutectic, the following effects can be obtained. For example, the sublimation drying treatment agent may be composed of a single sublimation substance in order to prevent the solvent from remaining. However, if a liquid film is formed on the surface of a substrate using a treatment liquid obtained by liquefying the sublimation substance and then the liquid film is solidified, the stress generated during the growth of grain boundaries becomes relatively large, as will be described later in detail. In contrast, according to the present invention, a eutectic structure of the first sublimation substance and the second sublimation substance is formed when the liquid film is solidified. This eutectic structure is finer than the precipitation structure of a single sublimation substance, and the stress generated during the growth of grain boundaries is suppressed. As a result, it greatly contributes to suppressing the collapse of the pattern. Moreover, the sublimation drying treatment agent according to the present invention has a lower melting point than that of a sublimation drying treatment agent made of a single sublimation substance, and therefore has the advantage of improving workability and reducing energy costs. Furthermore, the lowering of the melting point improves the controllability of the thickness of the liquid film, and a solidified film having a thickness corresponding to the pattern is formed, further enhancing the prevention of the collapse of the pattern. [Brief description of the drawings]

[0010] [Figure 1] 1 is a plan view showing a schematic configuration of a substrate processing apparatus capable of carrying out a first embodiment of a substrate processing method according to the present invention. [Diagram 2] 2 is a side view of the substrate processing apparatus shown in FIG. [Diagram 3] FIG. 2 is a partial cross-sectional view showing the configuration of a processing unit. [Figure 4] 2 is a block diagram showing an electrical configuration of a control unit that controls the processing unit. FIG. [Diagram 5]2 is a diagram showing the contents of a substrate processing performed in the substrate processing apparatus of FIG. 1; [Figure 6] FIG. 2 is an estimated state diagram of an example of a sublimation drying treatment agent according to the present invention. [Figure 7] 11 is a diagram summarizing verification results of the substrate processing method according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] First Embodiment <<Overall configuration of substrate processing equipment>> FIG. 1 is a plan view showing a schematic configuration of a substrate processing apparatus capable of carrying out a first embodiment of a substrate processing method according to the present invention. FIG. 2 is a side view of the substrate processing apparatus shown in FIG. 1. These drawings do not show the external appearance of the apparatus, but are schematic views showing the internal structure of the substrate processing apparatus 100 in an easy-to-understand manner by removing the outer wall panel and other parts of the configuration. The substrate processing apparatus 100 is a single-wafer type apparatus that is installed, for example, in a clean room and processes substrates W, each of which has a circuit pattern or the like (hereinafter referred to as a "pattern") formed only on one main surface. The first embodiment of the substrate processing method according to the present invention is carried out in the substrate processing apparatus 100. In this specification, the pattern-formed surface (one main surface) on which a pattern is formed is referred to as the "front surface Wf", and the other main surface on the opposite side on which no pattern is formed is referred to as the "rear surface Wb". The surface facing downward is referred to as the "lower surface", and the surface facing upward is referred to as the "upper surface". In addition, in this specification, the term "pattern-formed surface" refers to a surface of a substrate on which a concave-convex pattern is formed in any region, regardless of whether the surface is flat, curved, or concave-convex.

[0012] Here, the "substrate" in this embodiment can be any of various substrates such as a semiconductor wafer, a glass substrate for a photomask, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, etc. In the following, a substrate processing apparatus used mainly for processing semiconductor wafers will be described with reference to the drawings, but the present invention can be similarly applied to the processing of the various substrates exemplified above.

[0013] 1, the substrate processing apparatus 100 includes a substrate processing section 110 that processes substrates W, and an indexer section 120 that is coupled to the substrate processing section 110. The indexer section 120 includes a container holding section 121 that can hold a plurality of containers C (such as a FOUP (Front Opening Unified Pod), a SMIF (Standard Mechanical Interface) pod, or an OC (Open Cassette) that accommodates a plurality of substrates W in a sealed state) for accommodating substrates W, and an indexer robot 122 that accesses the containers C held by the container holding section 121 to take out unprocessed substrates W from the container C or store processed substrates W in the container C. Each container C accommodates a plurality of substrates W in a substantially horizontal position.

[0014] The indexer robot 122 comprises a base 122a fixed to the device housing, an articulated arm 122b rotatably provided around a vertical axis relative to the base 122a, and a hand 122c attached to the tip of the articulated arm 122b. The hand 122c is structured so that a substrate W can be placed on its upper surface and held thereon. Indexer robots having such articulated arms and hands for holding substrates are well known, and therefore detailed description thereof will be omitted.

[0015] The substrate processing section 110 includes a substrate transport robot 111 disposed approximately at the center in a plan view, and a plurality of processing units 1 disposed so as to surround the substrate transport robot 111. Specifically, a plurality of processing units 1 (eight in this example) are disposed facing the space in which the substrate transport robot 111 is disposed. The substrate transport robot 111 randomly accesses these processing units 1 to transfer the substrate W. Meanwhile, each processing unit 1 executes a predetermined process on the substrate W. In this embodiment, these processing units 1 have the same function. This enables parallel processing of a plurality of substrates W. In this embodiment, a transfer section 130 is provided to smoothly transfer the substrate W between the substrate processing section 110 and the indexer section 120.

[0016] <<Configuration of Processing Unit 1>> Fig. 3 is a partial cross-sectional view showing the configuration of a processing unit. Fig. 4 is a block diagram showing the electrical configuration of a control unit that controls the processing units. In this embodiment, a control unit 4 is provided for each processing unit 1, but a configuration may also be adopted in which a single control unit controls a plurality of processing units 1. Also, a configuration may also be adopted in which the processing units 1 are controlled by a control unit (not shown) that controls the entire substrate processing apparatus 100.

[0017] The processing unit 1 includes a chamber 2 having an internal space 21, and a spin chuck 3 accommodated in the internal space 21 of the chamber 2 to hold a substrate W. As shown in FIGS. 1 and 2, a shutter 23 is provided on a side surface of the chamber 2. A shutter opening / closing mechanism 22 (FIG. 4) is connected to the shutter 23, and opens and closes the shutter 23 in response to an opening / closing command from the control unit 4. More specifically, in the processing unit 1, when an unprocessed substrate W is carried into the chamber 2, the shutter opening / closing mechanism 22 opens the shutter 23, and the unprocessed substrate W is carried into the spin chuck 3 in a face-up position by the hand of the substrate transport robot 111. That is, the substrate W is placed on the spin chuck 3 with the front surface Wf facing upward. Then, when the hand of the substrate transport robot 111 retreats from the chamber 2 after the substrate is carried in, the shutter opening / closing mechanism 22 closes the shutter 23. Subsequently, in the internal space 21 of the chamber 2, chemical liquid, DIW (deionized water), an IPA processing liquid, and nitrogen gas are supplied to the surface Wf of the substrate W as described below, and the desired substrate processing is performed at a predetermined substrate processing temperature. After the substrate processing is completed, the shutter opening / closing mechanism 22 opens the shutter 23 again, and the hand of the substrate transport robot 111 removes the processed substrate W from the spin chuck 3. Thus, in this embodiment, the internal space 21 of the chamber 2 functions as a processing space in which substrate processing is performed while maintaining an environment at the substrate processing temperature. In this embodiment, the internal space 21 is maintained at room temperature (temperature range of 5°C to 35°C) as the "substrate processing temperature".

[0018] The spin chuck 3 includes a plurality of chuck pins 31 for gripping the substrate W, a spin base 32 formed in a disk shape along a horizontal direction to support the plurality of chuck pins 31, a central shaft 33 rotatably provided around a rotation axis C1 parallel to a surface normal extending from the center of the surface of the substrate W while being connected to the spin base 32, and a substrate rotation drive mechanism 34 for rotating the central shaft 33 around the rotation axis C1 by a motor. The plurality of chuck pins 31 are provided on the periphery of the upper surface of the spin base 32. In this embodiment, the chuck pins 31 are disposed at equal intervals in the circumferential direction. When the motor of the substrate rotation drive mechanism 34 is operated in response to a rotation command from the control unit 4 while the substrate W placed on the spin chuck 3 is gripped by the chuck pins 31, the substrate W rotates around the rotation axis C1. In addition, while the substrate W is being rotated in this manner, chemical liquid, IPA, DIW, processing liquid and nitrogen gas are successively supplied onto the front surface Wf of the substrate W from nozzles provided in the atmosphere blocking mechanism 5 in response to a supply command from the control unit 4.

[0019] The atmosphere blocking mechanism 5 has a blocking plate 51, an upper spin shaft 52 provided on the blocking plate 51 so as to be rotatable integrally therewith, and an upper nozzle 53 penetrating the center of the blocking plate 51 in the vertical direction. The blocking plate 51 is finished in a disk shape having a diameter substantially the same as or greater than that of the substrate W. The blocking plate 51 is disposed facing, with a gap therebetween, the upper surface of the substrate W held by the spin chuck 3. Therefore, the lower surface of the blocking plate 51 functions as a circular substrate facing surface 51a facing the entire front surface Wf of the substrate W. A cylindrical through hole 51b penetrating the blocking plate 51 in the vertical direction is formed in the center of the substrate facing surface 51a.

[0020] The upper spin shaft 52 is rotatably provided about a rotation axis (coincident with the rotation axis C1 of the substrate W) that passes through the center of the shielding plate 51 and extends vertically. The upper spin shaft 52 has a cylindrical shape. The inner peripheral surface of the upper spin shaft 52 is formed into a cylindrical surface centered on the rotation axis. The internal space of the upper spin shaft 52 communicates with the through hole 51b of the shielding plate 51. The upper spin shaft 52 is supported by a support arm 54 that extends horizontally above the shielding plate 51 so as to be rotatable relative to the support arm 54.

[0021] The upper nozzle 53 is disposed above the spin chuck 3. The upper nozzle 53 is supported by the support arm 54 in a state in which the upper nozzle 53 cannot rotate relative to the support arm 54. The upper nozzle 53 can be raised and lowered integrally with the shielding plate 51, the upper spin shaft 52, and the support arm 54. A discharge port 53a is provided at the lower end of the upper nozzle 53, and faces the center of the front surface Wf of the substrate W held by the spin chuck 3.

[0022] A shield plate rotation drive mechanism 55 (FIG. 4) including an electric motor and the like is coupled to the shield plate 51. The shield plate rotation drive mechanism 55 rotates the shield plate 51 and the upper spin shaft 52 relative to the support arm 54 around the rotation axis C1 in response to a rotation command from the control unit 4. A shield plate lift drive mechanism 56 is coupled to the support arm 54. The shield plate lift drive mechanism 56 lifts and lowers the shield plate 51, the upper spin shaft 52, and the upper nozzle 53 together with the support arm 54 in the vertical direction Z in response to a lift command from the control unit 4. More specifically, the shield plate lift drive mechanism 56 lifts and lowers the substrate facing surface 51a between a shield position (position shown in the upper right part of FIGS. 3 and 5) where the substrate facing surface 51a is close to the front surface Wf of the substrate W held by the spin chuck 3 and substantially blocks the space above the front surface Wf from the surrounding atmosphere, and a retracted position (not shown) retracted significantly above the shield position.

[0023] An upper end of the upper nozzle 53 is connected to a chemical liquid supply unit 61, a rinsing liquid supply unit 62, an organic solvent supply unit 63, a processing liquid supply unit 64, and a front surface side gas supply unit 65A.

[0024] The chemical supply unit 61 has a chemical pipe 611 connected to the upper nozzle 53 and a valve 612 interposed in the chemical pipe 611. The chemical pipe 611 is connected to a supply source of the chemical. In this embodiment, the chemical has only to have a function of cleaning the surface Wf of the substrate W, and for example, a chemical containing at least one of hydrofluoric acid (HF), hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid can be used as the acidic chemical. Also, for example, a chemical containing at least one of ammonia and a hydroxyl group can be used as the alkaline chemical. Note that, in this embodiment, hydrofluoric acid is used as the chemical. Therefore, when the valve 612 is opened in response to an opening / closing command from the control unit 4, the hydrofluoric acid chemical is supplied to the upper nozzle 53 and is discharged from the discharge port 53a toward the center of the surface of the substrate W.

[0025] The rinsing liquid supply unit 62 has a rinsing liquid pipe 621 connected to the upper nozzle 53, and a valve 622 installed in the rinsing liquid pipe 621. The rinsing liquid pipe 621 is connected to a supply source of the rinsing liquid. In this embodiment, DIW is used as the rinsing liquid, and when the valve 622 is opened in response to an opening / closing command from the control unit 4, the DIW is supplied to the upper nozzle 53 and discharged from the discharge port 53a toward the center of the surface of the substrate W. Note that, other than DIW, any of carbonated water, electrolytic ion water, hydrogen water, ozone water, and hydrochloric acid water with a diluted concentration (for example, about 10 ppm to 100 ppm) may be used as the rinsing liquid.

[0026] The organic solvent supply unit 63 is a unit for supplying an organic solvent as a low surface tension liquid having a specific gravity greater than that of air and a surface tension lower than that of water. The organic solvent supply unit 63 has an organic solvent pipe 631 connected to the upper nozzle 53 and a valve 632 interposed in the organic solvent pipe 631. The organic solvent pipe 631 is connected to a supply source of the organic solvent. In this embodiment, IPA is used as the organic solvent. When the valve 632 is opened in response to an opening / closing command from the control unit 4, the IPA is supplied to the upper nozzle 53 and discharged from the discharge port 53a toward the center of the surface of the substrate W. In addition to IPA, for example, methanol, ethanol, acetone, EG (ethylene glycol), and HFE (hydrofluoroether) can be used as the organic solvent. In addition, the organic solvent may be a liquid that is not only composed of a single component, but also mixed with other components. For example, it may be a mixed liquid of IPA and acetone, or a mixed liquid of IPA and methanol.

[0027] The processing liquid supply unit 64 is a unit that supplies a processing liquid that functions as a drying auxiliary liquid when drying the substrate W held by the spin chuck 3, to the front surface Wf of the substrate W. The processing liquid supply unit 64 has a processing liquid pipe 641, a valve 642 interposed in the processing liquid pipe 641, and a processing liquid supply part 643 that functions as a supply source of the processing liquid. The processing liquid pipe 641 connects the upper nozzle 53 and the processing liquid supply part 643 to each other.

[0028] When the processing liquid supply unit 643 is supplied with a processing agent for sublimation drying, which is a mixture of a first sublimable substance and a second sublimable substance different from each other, the processing liquid supply unit 643 heats the processing agent for sublimation drying to liquefy the processing liquid to prepare the processing liquid. The processing liquid is then stored in a storage tank (not shown). The processing liquid supply unit 643 has a pressure-feeding mechanism such as a pump and has a function of sending the processing liquid from the storage tank to the upper nozzle 53 through the processing liquid pipe 641. Therefore, when the valve 642 is opened in response to a command from the control unit 4, the processing liquid flows through the processing liquid pipe 641 and is pressure-fed toward the upper nozzle 53. As a result, the processing liquid (liquid processing agent for sublimation drying) is supplied from the outlet 53a of the upper nozzle 53 toward the center of the front surface Wf of the substrate W. On the other hand, when the valve 642 is closed in response to a command from the control unit 4, the pressure-feeding of the processing liquid is stopped, and the supply of the processing liquid from the upper nozzle 53 is also stopped.

[0029] In this embodiment, camphor (melting point 175° C.) is used as the first sublimable substance, and cyclohexanone oxime (melting point 90° C.) is used as the second sublimable substance, and a solid sublimation drying treatment agent obtained by mixing the two without using a solvent is appropriately replenished to the treatment liquid supply unit 643. Of course, a liquid sublimation drying treatment agent may be replenished to the treatment liquid supply unit 643 and stored in the storage tank. That is, the sublimation drying treatment agent replenished to the substrate processing apparatus 100 may be in either a solid phase or a liquid phase.

[0030] In addition, in this embodiment, the processing liquid supply part 643 is built in the processing liquid supply unit 64, but it may be disposed separately from the processing liquid supply unit 64. In other words, in the substrate processing apparatus 100, a unit equivalent to the processing liquid supply part 643 may be separately provided outside the processing liquid supply unit 64, and the processing liquid (a processing agent for sublimation drying in a liquid state) may be supplied to the upper nozzle 53 from the unit via the processing liquid piping 641.

[0031] Here, in this specification, "sublimable" means that a single substance, compound, or mixture has a property of undergoing phase transition from solid to gas or from gas to solid without passing through a liquid state, and "sublimable substance" means a substance having such sublimability. The mixture ratio of the first sublimable substance and the second sublimable substance (in this embodiment, the concentration (weight percent) of cyclohexanone oxime) and the types of the first sublimable substance and the second sublimable substance will be described in detail later.

[0032] The front side gas supply unit 65A has a gas supply pipe 651 connected to the upper nozzle 53 and a valve 652 for opening and closing the gas supply pipe 651. The gas supply pipe 651 is connected to a gas supply source. In this embodiment, dehumidified nitrogen gas is used as the gas, and when the valve 652 is opened in response to an opening / closing command from the control unit 4, the nitrogen gas is supplied to the upper nozzle 53 and sprayed from the outlet 53a toward the center of the front surface of the substrate W. Note that, in addition to nitrogen gas, an inert gas such as dehumidified argon gas may be used as the gas. This point is the same in the rear side gas supply unit 65B described next.

[0033] 3, the back surface side gas supply unit 65B has a gas supply pipe 653 and a valve 654 for opening and closing the gas supply pipe 653. One end of the gas supply pipe 653 is connected to a gas supply source, and the other end is connected to the gas flow path 321. The gas flow path 321 has a cylindrical shape formed between the inner peripheral surface of a hole extending vertically downward from a central opening 322 that opens at the center of the upper surface of the spin base 32, and the outer peripheral surface of the lower nozzle 71 inserted into the hole. Therefore, similar to the front surface side gas supply unit 65A, when the valve 654 is opened in response to an opening / closing command from the control unit 4, dehumidified nitrogen gas flows radially in all directions between the back surface Wb of the substrate W and the upper surface of the spin base 32. As a result, the space between the substrate W and the spin base 32 is filled with nitrogen gas.

[0034] The lower nozzle 71 constituting the gas flow path 321 in this way is connected to a cooling liquid supply unit 66. The cooling liquid supply unit 66 has a cooling liquid pipe 661 connected to the lower nozzle 71 and a valve 662 interposed in the cooling liquid pipe 661. The cooling liquid pipe 661 is connected to a cooling liquid supply source. In this embodiment, DIW cooled to a temperature close to 0°C (hereinafter referred to as "low-temperature DIW") is used as the cooling liquid. When the valve 662 is opened in response to an opening / closing command from the control unit 4, the low-temperature DIW is supplied to the lower nozzle 71 and discharged toward the center of the back surface of the substrate W. This cools the substrate W from the back surface Wb side, and as will be described later, efficiently promotes solidification of the liquid film formed on the front surface Wf of the substrate W. Note that, other than the low-temperature DIW, a coolant such as nitrogen gas below freezing point may be fed into the lower nozzle 71 to cool the substrate W.

[0035] In the processing unit 1, an exhaust bucket 80 is provided to surround the spin chuck 3. A plurality of cups 81, 82 (first cup 81 and second cup 82) are disposed between the spin chuck 3 and the exhaust bucket 80, and a plurality of guards 84-86 (first guard 84 to third guard 86) are provided to receive processing liquid splashed around the substrate W. Guard lifting and lowering drive mechanisms 87-89 (first to third guard lifting and lowering drive mechanisms 87-89) are connected to the guards 84-86, respectively. The guard lifting and lowering drive mechanisms 87-89 independently lift and lower the guards 84-86 in response to lifting and lowering commands from the control unit 4. The first guard lifting and lowering drive mechanism 87 is not shown in FIG. 3.

[0036] The control unit 4 has a calculation unit such as a CPU, a storage unit such as a fixed memory device and a hard disk drive, and an input / output unit. The storage unit stores a program executed by the calculation unit. The control unit 4 controls each part of the apparatus according to the program, thereby performing the substrate processing shown in FIG. 5 using the processing liquid described below. The processing liquid and the substrate processing method will be described in detail below.

[0037] <<Processing liquid>> Next, the treatment liquid used in this embodiment will be described below. The treatment liquid in this embodiment is a mixture of camphor (first sublimable substance) and cyclohexanone oxime (second sublimable substance) in a eutectic composition or a composition close to eutectic, which is obtained by heating and liquefying a treatment agent for sublimation drying. The treatment liquid in this embodiment serves to assist the drying process in the drying process for removing the liquid present on the pattern-formed surface of the substrate.

[0038] It is well known that camphor is a sublimable substance with a melting point of 175°C, and cyclohexanone oxime is a sublimable substance with a melting point of 90°C, but there has not been sufficient knowledge about a mixture of the two. Therefore, the inventors of the present application liquefied a mixture of camphor and cyclohexanone oxime (treatment agent for sublimation drying) in the blending ratio shown in Table 1 to prepare a treatment liquid, and then slowly cooled the treatment liquid. Then, the precipitation temperatures of primary α and β crystals and eutectic structures were obtained.

[0039] [Table 1]

[0040] The inventors of the present application then observed the precipitated structure. As a result, it is estimated that the sublimation drying treatment agent shows a eutectic reaction, and its phase diagram is as shown in FIG. 6. FIG. 6 is an estimated phase diagram of an example of the sublimation drying treatment agent according to the present invention. The temperature and composition of the eutectic point derived from the phase diagram shown in the figure are estimated to be "33°C (see the open circle in FIG. 6)" and "concentration of cyclohexanone oxime in the sublimation drying treatment agent: 45 weight percent", respectively. Therefore, the inventors of the present application prepared a sublimation drying treatment agent in which camphor and cyclohexanone oxime are mixed at (55 weight percent: 45 weight percent), and measured the temperature of the eutectic point (hereinafter referred to as "eutectic temperature"), which was "36°C". Therefore, it was confirmed that the composition at the eutectic point of the sublimation drying treatment agent used in the embodiment (hereinafter referred to as "eutectic composition") is as estimated above. In addition, from the observation of the structure, it was confirmed that a sublimation drying agent mixed with a eutectic composition or a composition close to eutectic can obtain a finer eutectic structure than the precipitation structure of a single sublimation substance. In the case of having such a fine eutectic structure, the stress generated during the growth of the crystal grain boundary is suppressed. Therefore, as described later, by using a sublimation drying agent showing a eutectic reaction as a drying assistant liquid, it is expected that the collapse of the pattern can be suppressed. Moreover, the melting point of the sublimation drying agent is lower than that of a sublimation drying agent made of a single sublimation substance, which makes it possible to improve the workability and reduce the energy cost for heating the sublimation drying agent. Furthermore, the lowering of the melting point makes it possible to improve the film thickness controllability of the liquid film.

[0041] Here, it is considered desirable to use a sublimation drying treatment agent having a eutectic composition from the viewpoint of, for example, a fine structure and a lowered melting point, but the same effect can be obtained with a composition close to the eutectic composition (hereinafter referred to as a "near-eutectic composition"). For example, in a sublimation drying treatment agent in which camphor and cyclohexanone oxime are mixed, the concentration of cyclohexanone oxime is desirably 40 to 60 weight percent, more desirably the concentration of cyclohexanone oxime is on the eutectic composition or hypereutectic side richer than the eutectic composition, that is, 45 to 60 weight percent, and particularly desirably 45 to 55 weight percent.

[0042] <<Substrate processing method>> Next, a substrate processing method using the substrate processing apparatus 100 shown in Fig. 1 will be described with reference to Fig. 5. Fig. 5 is a diagram showing the contents of the substrate processing performed by the substrate processing apparatus of Fig. 1. In the figure, a flowchart of the substrate processing performed by one processing unit 1 is shown on the left side. Also, the upper right side, the middle right side, and the lower right side are respectively shown as schematic diagrams of a liquid film forming process, a solidified film forming process, and a sublimation process, and a part of the surface Wf of the substrate W is shown in an enlarged manner. However, for the purpose of easy understanding, the dimensions and numbers of each part are exaggerated or simplified as necessary.

[0043] The processing object in the substrate processing apparatus 100 is, for example, a silicon wafer, and an uneven pattern PT is formed on a surface Wf, which is a pattern formation surface. In this embodiment, the protrusions PT1 have a height in the range of 100 to 600 nm and a width in the range of 5 to 50 nm. The shortest distance between two adjacent protrusions PT1 (shortest width of the recess) is in the range of 5 to 150 nm. The aspect ratio of the protrusions PT1, i.e., the value obtained by dividing the height by the width (height H / width WD), is 5 to 35.

[0044] The pattern PT may be a pattern in which a line-shaped pattern formed by fine trenches is repeatedly arranged. The pattern PT may be formed by providing a thin film with a plurality of fine holes (voids or pores). The pattern PT includes, for example, an insulating film. The pattern PT may also include a conductive film. More specifically, the pattern PT is formed by a laminated film in which a plurality of films are laminated, and may further include an insulating film and a conductive film. The pattern PT may be a pattern composed of a single layer film. The insulating film may be a silicon oxide film or a silicon nitride film. The conductive film may be an amorphous silicon film into which impurities are introduced to reduce resistance, or may be a metal film (for example, a TiN film). The pattern PT may be formed at the front end or at the back end. The pattern PT may be a hydrophobic film or a hydrophilic film. For example, a TEOS film (a type of silicon oxide film) is included as a hydrophilic film.

[0045] 5 are performed in an atmospheric pressure environment at room temperature unless otherwise specified. Here, the atmospheric pressure environment refers to an environment of 0.7 to 1.3 atmospheres, with the standard atmospheric pressure (1 atmosphere, 1013 hPa) at the center. In particular, when the substrate processing apparatus 100 is disposed in a clean room where the pressure is positive, the environment of the surface Wf of the substrate W becomes higher than 1 atmosphere.

[0046] Before an unprocessed substrate W is loaded into the processing unit 1, the control unit 4 issues a command to each part of the apparatus, and the processing unit 1 is set to an initial state. That is, the shutter 23 (FIGS. 1 and 2) is closed by the shutter opening / closing mechanism 22. The spin chuck 3 is positioned and stopped at a position suitable for loading the substrate W by the substrate rotation driving mechanism 34, and the chuck pins 31 are in an open state by a chuck opening / closing mechanism (not shown). The shield plate 51 is positioned at a retreat position by the shield plate lifting / lowering driving mechanism 56, and the rotation of the shield plate 51 by the shield plate rotation driving mechanism 55 is stopped. All of the guards 84 to 86 are moved downward and positioned. Furthermore, all of the valves 612, 622, 632, 642, 652, 654, and 662 are closed.

[0047] When an unprocessed substrate W is transported by the substrate transport robot 111, the shutter 23 opens. In synchronization with the opening of the shutter 23, the substrate W is transported into the internal space 21 of the chamber 2 by the substrate transport robot 111, and is delivered to the spin chuck 3 with the front surface Wf facing upward. Then, the chuck pins 31 are closed, and the substrate W is held by the spin chuck 3 (Step S1: Transporting the Substrate).

[0048] Following the loading of the substrate W, the substrate transport robot 111 retreats to the outside of the chamber 2, and the shutter 23 closes again. Then, the control unit 4 controls the motor of the substrate rotation drive mechanism 34 to rotate the spin chuck 3 at a predetermined processing speed (within a range of about 10 to 3000 rpm, for example, 800 to 1200 rpm). ) and maintains that processing speed. The controller 4 also controls the shield plate lifting drive mechanism 56 to lower the shield plate 51 from the retracted position to the shielding position (step S2). The controller 4 also controls the guard lifting drive mechanisms 87-89 to lift the first guard 84-third guard 86 to their upper positions, thereby causing the first guard 84 to face the peripheral end surface of the substrate W.

[0049] When the rotation of the substrate W reaches the processing speed, the control unit 4 then opens the valve 612. As a result, a chemical (HF in this embodiment) is discharged from the discharge port 53a of the upper nozzle 53 and supplied to the front surface Wf of the substrate W. On the front surface Wf of the substrate W, the HF is subjected to centrifugal force due to the rotation of the substrate W and moves to the peripheral portion of the substrate W. As a result, the entire front surface Wf of the substrate W is subjected to chemical cleaning with HF (step S3). At this time, the HF that has reached the peripheral portion of the substrate W is discharged from the peripheral portion of the substrate W to the side of the substrate W, received by the inner wall of the first guard 84, and sent to a waste liquid treatment facility outside the apparatus along a drainage path not shown. This chemical cleaning by supplying HF continues for a predetermined cleaning time, and when that time has elapsed, the control unit 4 closes the valve 612 to stop the discharge of HF from the upper nozzle 53.

[0050] Following the chemical cleaning, a rinse process using a rinse liquid (DIW) is performed (step S4). In this DIW rinse, the control unit 4 opens the valve 622 while maintaining the positions of the first guard 84 to the third guard 86. As a result, DIW is supplied as a rinse liquid from the outlet 53a of the upper nozzle 53 to the center of the front surface Wf of the substrate W that has been subjected to the chemical cleaning process. Then, the DIW is moved to the peripheral portion of the substrate W by the centrifugal force caused by the rotation of the substrate W. As a result, the HF adhering to the substrate W is washed away by the DIW. At this time, the DIW discharged from the peripheral portion of the substrate W is discharged from the peripheral portion of the substrate W to the side of the substrate W and is sent to a waste liquid treatment facility outside the apparatus in the same manner as the HF. This DIW rinse continues for a predetermined rinse time, and when that time has elapsed, the control unit 4 closes the valve 622 to stop the discharge of the DIW from the upper nozzle 53.

[0051] After the DIW rinse is completed, a replacement process is performed with an organic solvent (IPA in this embodiment) having a surface tension lower than that of the DIW (step S5). In the IPA replacement, the control unit 4 controls the guard lifting drive mechanisms 87 and 88 to lower the first guard 84 and the second guard 85 to the lower position, thereby causing the third guard 86 to face the peripheral end surface of the substrate W. Then, the control unit 4 opens the valve 632. As a result, IPA is discharged as a low surface tension liquid from the discharge port 53a of the upper nozzle 53 toward the center of the front surface Wf of the substrate W to which the DIW is attached. The IPA supplied to the front surface Wf of the substrate W spreads over the entire surface Wf of the substrate W by receiving the centrifugal force due to the rotation of the substrate W. As a result, the DIW (rinsing liquid) attached to the front surface Wf of the substrate W is replaced by IPA over the entire front surface Wf of the substrate W. The IPA moving on the front surface Wf of the substrate W is discharged from the peripheral portion of the substrate W to the side of the substrate W, received by the inner wall of the third guard 86, and sent to a recovery facility along a recovery path (not shown). This IPA replacement continues for a predetermined replacement time, and when that time has elapsed, the control unit 4 closes the valve 632 to stop the discharge of IPA from the upper nozzle 53.

[0052] After the IPA replacement, a sublimation drying step (step S6) corresponding to the first embodiment of the substrate processing method of the present invention is performed. This sublimation drying step includes a liquid film forming step (step S6-1) for forming a liquid film of the processing liquid, a solidified film forming step (step S6-2) for solidifying the liquid film of the processing liquid to form a solidified film of a processing agent for sublimation drying (=camphor+cyclohexanone oxime), and a sublimation step (step S6-3) for sublimating the solidified film and removing it from the surface Wf of the substrate W.

[0053] In step S6-1, the control unit 4 controls the second guard lifting drive mechanism 88 to raise the second guard 85 to the upper position, thereby causing the second guard 85 to face the peripheral edge surface of the substrate W. Then, the control unit 4 opens the valve 642. As a result, as shown in the upper right part of FIG. 5, the processing liquid is discharged as a drying auxiliary liquid from the discharge port 53a of the upper nozzle 53 toward the center of the front surface Wf of the substrate W to which the IPA is attached, and is supplied to the front surface Wf of the substrate W. The processing liquid on the front surface Wf of the substrate W is subjected to centrifugal force due to the rotation of the substrate W and spreads over the entire front surface Wf of the substrate W. As a result, the IPA attached to the front surface Wf of the substrate W is replaced by the processing liquid over the entire front surface Wf of the substrate W, and a liquid film LF of the processing liquid is formed on the front surface Wf as shown in the drawing in the upper right part of FIG. The thickness of the liquid film LF is greater than the height of the convex portion PT1, and the entire pattern PT is immersed in the liquid film LF. In addition, it is desirable to adjust the thickness of the liquid film LF by appropriately changing the rotation speed of the substrate W within a range of 300 rpm to 3000 rpm depending on the concentration of cyclohexanone oxime contained in the processing liquid, the height of the protrusion PT1, and the aspect ratio. For example, if it is desired to set the liquid film LF thick, the rotation speed should be set low, and conversely, if it is desired to set the liquid film LF thin, the rotation speed should be set low. When the liquid film LF having the desired thickness is thus formed, the control unit 4 closes the valve 642 to stop the discharge of the processing liquid from the upper nozzle 53.

[0054] In the next step S6-2, the control unit 4 opens the valve 652. As a result, as shown in the middle right part of FIG. 5, dehumidified nitrogen gas is discharged toward the front surface Wf of the substrate W, which is rotating while covered with the liquid film LF of the processing liquid. The control unit 4 also opens the valve 662. As a result, low-temperature DIW is supplied from the lower nozzle 71 to the center of the back surface of the substrate W. In this way, the substrate W is cooled, and solidification of the liquid film LF formed on the front surface Wf of the substrate W is efficiently promoted. In addition, in this embodiment, a processing agent for sublimation drying mixed with a eutectic composition or a composition close to eutectic is used. For example, in the processing agent for sublimation drying with a eutectic composition, a fine eutectic structure is precipitated uniformly over the entire liquid film LF. In addition, on the hypoeutectic side where the concentration of cyclohexanone oxime is lower than the eutectic composition, when the temperature drops to the liquidus line LL1 (see FIG. 6), camphor is precipitated as primary crystal α in a part of the liquid film LF, and the processing liquid L and the primary crystal α are mixed. Then, as the temperature is further decreased, the camphor precipitate grows, and when it is cooled to the eutectic temperature (33°C), a fine eutectic structure is uniformly formed in the remaining portion. On the other hand, on the hypereutectic side where the concentration of cyclohexanone oxime is higher than the eutectic composition, when the temperature is decreased to the liquidus line LL2 (see FIG. 6), cyclohexanone oxime precipitates as primary crystals β in part of the liquid film LF, and the treatment liquid L and the primary crystals β are mixed. Then, as the temperature is further decreased, the cyclohexanone oxime precipitate grows, and when it is cooled to the eutectic temperature (33°C), a fine eutectic structure is uniformly formed in the remaining portion.

[0055] In this embodiment, nitrogen gas is sprayed in parallel with the rotation of the substrate W to promote precipitation of the solidified film SF. The timing at which the valve 652 is opened, i.e., the timing at which the nitrogen gas starts to be discharged, may be before or after the precipitation of the primary crystals α and β or the eutectic structure starts. The supply of nitrogen gas or low-temperature DIW is not essential for forming a solidified film of the treatment agent for sublimation drying, but it is desirable to use only nitrogen gas, only low-temperature DIW, or both in order to improve throughput.

[0056] Next, the control unit 4 executes the sublimation step (step S6-3). The control unit 4 controls the second guard lifting drive mechanism 88 to lower the second guard 85 to the lower position, thereby causing the third guard 86 to face the peripheral end surface of the substrate W. In this embodiment, the control unit 4 maintains the rotation speed of the substrate W from the solidified film SF formation step (step S6-2), but may accelerate it to a high speed. The control unit 4 also controls the shield plate rotation drive mechanism 55 to rotate the shield plate 51 in the same direction as the rotation of the substrate W at the same speed. As the substrate W rotates, the contact speed between the solidified film SF and the surrounding atmosphere increases. This can promote the sublimation of the solidified film SF, and the solidified film SF can be sublimated in a short period of time. However, the rotation of the shield plate 51 is not an essential component of the sublimation step, but is an optional component.

[0057] In the sublimation step S6-3, the control unit 4 maintains the valve 652 open from the formation of the solidified film SF, and dehumidified nitrogen gas is discharged from the outlet 53a of the upper nozzle 53 toward the center of the surface Wf of the substrate W in a rotating state, as shown in the lower right part of FIG. 5. This makes it possible to perform the sublimation step while keeping the blocking space between the surface Wf of the substrate W and the substrate-facing surface 51a of the blocking plate 51 in a low humidity state. In this sublimation step S6-3, the heat of sublimation is taken away with the sublimation of the solidified film SF, and the solidified film SF is maintained at a temperature equal to or lower than the eutectic temperature. Therefore, it is possible to effectively prevent the structures (eutectic structure, eutectic structure + camphor, eutectic structure + cyclohexanone oxime) constituting the solidified film SF from melting. As a result, since there is no liquid phase between the patterns PT on the surface Wf of the substrate W, the substrate W can be dried while mitigating the problem of the pattern PT collapsing.

[0058] In addition, in the sublimation process S6-3, the control unit 4 closes valve 662 to stop the supply of low-temperature DIW, while opening valve 654 to fill the space between the back surface Wb of the substrate W and the spin base 32 with dehumidified nitrogen gas, thereby promoting drying of the back surface Wb of the substrate W.

[0059] When a predetermined sublimation time has elapsed since the start of the sublimation drying step S6, in step S7, the control unit 4 closes the valves 652, 654 to stop the supply of nitrogen gas, and controls the motor of the substrate rotation drive mechanism 34 to stop the rotation of the spin chuck 3. The control unit 4 also controls the shield plate rotation drive mechanism 55 to stop the rotation of the shield plate 51, and controls the shield plate lift drive mechanism 56 to lift the shield plate 51 from the shielding position and position it at the retreat position. Furthermore, the control unit 4 controls the third guard lift drive mechanism 89 to lower the third guard 86, and retreats all the guards 86 to 88 downward from the peripheral end surface of the substrate W.

[0060] Thereafter, the control unit 4 controls the shutter opening / closing mechanism 22 to open the shutter 23 (FIGS. 1 and 2), and then the substrate transport robot 111 enters the internal space of the chamber 2 and transports the processed substrate W, which has been released from the chuck pins 31, out of the chamber 2 (step S8). When the substrate W has been transported out and the substrate transport robot 111 has moved away from the processing unit 1, the control unit 4 controls the shutter opening / closing mechanism 22 to close the shutter 23.

[0061] As described above, in this embodiment, the IPA attached to the surface Wf of the substrate W is replaced with the above-mentioned processing liquid (a liquefied processing agent for sublimation drying, which is a mixture of camphor and cyclohexanone oxime in a eutectic composition or a composition close to eutectic), to form a liquid film LF. The liquid film LF is then cooled to a temperature lower than the eutectic temperature to form a solidified film SF containing a eutectic structure, which is then sublimated. In other words, the solidified film SF is removed from the surface Wf of the substrate W without passing through a liquid state. Therefore, by using the substrate processing method according to this embodiment, it is possible to dry the substrate W while preventing the collapse of the pattern PT.

[0062] In the above embodiment, the sublimation drying treatment agent is a mixture of camphor (first sublimable substance) and cyclohexanone oxime (second sublimable substance) in a eutectic or near-eutectic composition, as described above, and therefore the following effects can be obtained. As described above, in the conventional technology using a sublimation drying treatment agent in which a sublimable substance is dissolved in a solvent, the solvent may remain in the solidified film SF. In contrast, the sublimation drying treatment agent used in this embodiment does not contain a solvent, so the solvent does not remain in the solidified film SF. As a result, the collapse of the pattern PT on the surface Wf of the substrate W can be more effectively suppressed.

[0063] In addition, in order to prevent the solvent from remaining, it is one measure to use a single sublimable substance as the treatment agent for sublimation drying. However, after forming a liquid film LF on the surface Wf of the substrate W with a treatment liquid obtained by liquefying the sublimable substance, when the liquid film LF is cooled, the primary crystals of the sublimable substance are dispersed and precipitated in the liquid film LF, and grow individually as the temperature further decreases. Therefore, the crystal grain boundaries in the solidified film SF grow unevenly. As a result, the stress generated during the growth of the crystal grain boundaries becomes relatively large. In contrast, according to this embodiment, a eutectic structure of camphor and cyclohexanone oxime is formed when the liquid film LF is solidified. This eutectic structure is finer than the precipitated structure of a single sublimable substance, so the stress generated during the growth of the crystal grain boundaries is suppressed. As a result, the collapse of the pattern PT is effectively suppressed. Moreover, the eutectic temperature of the sublimation drying agent is lower than the melting point of a sublimation drying agent made of a single sublimable substance, which improves workability and reduces the energy cost required to liquefy (heat) the sublimation drying agent. Furthermore, the lowering of the melting point improves the film thickness controllability of the liquid film LF, and a solidified film SF having a thickness corresponding to the height H of the pattern PT (see the lower right of Figure 5) is formed, which further improves the prevention of the collapse of the pattern PT.

[0064] As described above, step S6-1 corresponds to an example of the "liquid film forming process" of the present invention, step S6-2 corresponds to an example of the "solidified film forming process" of the present invention, and step S6-3 corresponds to an example of the "sublimation process" of the present invention.

[0065] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-mentioned embodiment, the sublimation step (step S6-3) is performed after the solidified film formation step (step S6-2) is completed, but the two steps may be partially overlapped. For example, in the solidified film formation step (step S6-2), the substrate W may be rotated at a low speed (for example, 100 rpm) to perform the precipitation process of the eutectic structure and the filling process (dwell) of the sublimable substance into the pattern PT at the same time. In this case, the sublimation step may be started before the sublimable substance filled between the patterns PT is completely solidified. In other words, the solid of the sublimable substance may be sublimated while being maintained in a pre-crystallization transition state before crystallization. This allows the solid of the sublimable substance to be removed from the surface of the substrate W without passing through a crystallized state. Therefore, the influence of the stress caused by the crystallization of the solid of the sublimable substance can be reduced, and the collapse of the pattern PT on the substrate W can be more effectively reduced.

[0066] In the above embodiment, camphor and cyclohexanone oxime are used as the first and second sublimable substances, respectively, but the combination of the first and second sublimable substances is not limited to this. For example, the first sublimable substance may be a sublimable substance having a first melting point higher than the substrate processing temperature (at least one selected from the group consisting of camphor, cyclohexanone oxime, and acetoxime (melting point 58°C-63°C)), while the second sublimable substance may be a sublimable substance having a second melting point higher than the substrate processing temperature (at least one selected from the group consisting of camphor, cyclohexanone oxime, and acetoxime excluding the first sublimable substance). In addition, the first sublimable substance may be a sublimable substance having a first melting point higher than the substrate processing temperature (at least one selected from the group consisting of camphor, cyclohexanone oxime, and acetoxime), while the second sublimable substance may be a sublimable substance having a second melting point lower than the substrate processing temperature (at least one selected from the group consisting of cyclohexanol (melting point 23°C-25°C) or tert-butyl alcohol (melting point 25°C)). EXAMPLES

[0067] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples. Therefore, it is possible to carry out the present invention by making appropriate modifications within the scope of the gist of the present invention, and all of these modifications are included in the technical scope of the present invention.

[0068] Here, the treatment liquid for sublimation drying, which is a mixture of camphor (first sublimable substance) and cyclohexanone oxime (second sublimable substance) in the following ratio, was heated and liquefied to treat the substrate in the procedure shown in Fig. 5. The substrate treatment conditions were the same except for the treatment liquid for sublimation drying.

[0069] Sublimation drying treatment agent A = Camphor 60wt% + Cyclohexanone oxime 40wt% Sublimation drying treatment agent B = Camphor 55wt% + Cyclohexanone oxime 45wt% Sublimation drying treatment agent C = Camphor 50wt% + Cyclohexanone oxime 50wt% Sublimation drying treatment agent D = Camphor 40wt% + Cyclohexanone oxime 60wt% Sublimation drying treatment agent E = Camphor 0wt% + Cyclohexanone oxime 100wt%

[0070] The collapse rate of the pattern on the substrate W after sublimation drying was then examined. The results are shown in FIG. 7. As is clear from the figure, by using the treatment agents A to D for sublimation drying having a eutectic composition or a composition close to eutectic, the collapse rate of the pattern PT can be reduced more than when the treatment agent E for sublimation drying consisting of only a single sublimable substance is used. In other words, the concentration of cyclohexanone oxime is preferably 40 weight percent or more and 60 weight percent or less, more preferably cyclohexanone oxime is on the eutectic composition or hypereutectic side higher than the eutectic composition, that is, 45 weight percent or more and 60 weight percent or less, and particularly preferably 45 weight percent or more and 55 weight percent or less. [Industrial Applicability]

[0071] The present invention can be applied to any substrate processing technology that uses a sublimable substance that undergoes a phase transition from solid to gas without passing through a liquid state, and dries a substrate having a pattern formed on its surface. [Explanation of symbols]

[0072] L: Processing liquid LF: Liquid film (sublimation drying agent) PT…Pattern SF…solidified film W…Substrate Wb: Back side (of the board) Wf: (substrate) surface

Claims

1. a liquid film forming step of supplying a treatment liquid obtained by liquefying a treatment agent for sublimation drying, the treatment liquid being a mixture of a first sublimable substance and a second sublimable substance different from each other in a eutectic composition or a near-eutectic composition, onto a surface of a substrate on which a pattern has been formed, to form a liquid film of the treatment liquid on the surface of the substrate; a solidified film forming step of solidifying the liquid film of the treatment liquid to form a solidified film of the treatment agent for sublimation drying; a sublimation step of sublimating the solidified film and removing it from the surface of the substrate, the first sublimable material is camphor; the second sublimable substance is cyclohexanone oxime; The weight percentage of the second sublimable substance in the treatment agent for sublimation drying is in the range of the weight percentage of the eutectic composition or more and 60% or less. A substrate processing method comprising:

2. 2. The substrate processing method according to claim 1, the liquid film forming step, the solidified film forming step, and the sublimation step are performed at room temperature.

3. A sublimation drying treatment agent that is supplied in a liquid state to a surface of a substrate on which a pattern is formed, and then solidified and sublimated in this order, thereby drying the surface of the substrate, the treatment agent comprising: A first sublimable substance and a second sublimable substance different from each other are mixed in a eutectic composition or a near-eutectic composition, the first sublimable material is camphor; the second sublimable substance is cyclohexanone oxime; The weight percentage of the second sublimable substance in the treatment agent for sublimation drying is in the range of the weight percentage of the eutectic composition or more and 60% or less. A sublimation drying treatment agent characterized by:

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