JP2018107426A - Substrate processing device and substrate processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate processing device and a substrate processing method capable of removing a liquid attached to the surface of a substrate while collapse of a pattern formed on the surface of the substrate is prevented.SOLUTION: A substrate processing device 1 according to the present invention includes supply means 21 for supplying a treatment liquid 62 containing a sublimable substance in a molten state to a pattern formation surface of a substrate, solidifying means for solidifying the treatment liquid 62 on the pattern formation surface to form a solidified body 63, and sublimation means for sublimating the solidified body 63 and removing the solidified body 63 from the pattern formation surface, and the vapor pressure of the treatment liquid 62 at 20°C to 25°C is 5 kPa or more and the surface tension at 20°C to 25°C is 25 mN/m or less.SELECTED DRAWING: Figure 1

Description

  The present invention includes a semiconductor substrate, a glass substrate for photomask, a glass substrate for liquid crystal display, a glass substrate for plasma display, a substrate for FED (Field Emission Display), a substrate for optical disk, a substrate for magnetic disk, a substrate for magneto-optical disk, etc. The present invention relates to a substrate processing apparatus and a substrate processing method for removing liquid adhering to various substrates (hereinafter simply referred to as “substrate”) from the substrate.

  In the manufacturing process of electronic components such as semiconductor devices and liquid crystal display devices, various wet processes using liquid are performed on the substrate, and then the substrate is subjected to a drying process for removing the liquid adhering to the substrate by the wet process. Apply to.

  Examples of the wet process include a cleaning process for removing contaminants on the substrate surface. For example, reaction by-products (etching residues) are present on the substrate surface on which a fine pattern having irregularities is formed by a dry etching process. In addition to the etching residue, metal impurities, organic contaminants, and the like may adhere to the substrate surface. In order to remove these substances, a cleaning process such as supplying a cleaning solution to the substrate is performed.

  After the cleaning process, a rinsing process for removing the cleaning liquid with a rinsing liquid and a drying process for drying the rinsing liquid are performed. The rinsing process includes a rinsing process in which a rinsing liquid such as deionized water (DIW) is supplied to the substrate surface to which the cleaning liquid is adhered, and the cleaning liquid on the substrate surface is removed. Then, the drying process which dries a board | substrate by removing a rinse liquid is performed.

  In recent years, with the miniaturization of a pattern formed on a substrate, the aspect ratio (ratio of height to width in a pattern convex portion) at a convex portion of a pattern having irregularities is increasing. For this reason, during the drying process, the surface tension acting on the boundary surface between the liquid such as cleaning liquid or rinse liquid that has entered the concave portion of the pattern and the gas in contact with the liquid attracts the adjacent convex portions in the pattern and collapses. There is a problem of so-called pattern collapse.

  As a drying technique for the purpose of preventing the collapse of a pattern that is troubled by such surface tension, for example, in Patent Document 1 below, a solution is brought into contact with a substrate on which a structure (pattern) is formed. There is disclosed a method of changing to a solid to form a pattern support (solidified body) and removing the support from a solid phase to a gas phase without passing through a liquid phase. Patent Document 1 discloses that a sublimable substance of at least one of a methacrylic resin material, a styrene resin material, and a fluorocarbon material is used as a support material.

  In Patent Document 2 and Patent Document 3, a sublimable substance solution is supplied onto a substrate, a solvent in the solution is dried, the substrate is filled with a solidified substance of the sublimable substance, and the solidified body is sublimated. Technology is disclosed. According to these patent documents, since the surface tension does not act on the boundary surface between the solidified body and the gas in contact with the solidified body, the collapse of the pattern due to the surface tension can be suppressed.

  In Patent Document 4, a melt of t-butanol (sublimation substance) is supplied to a substrate to which a liquid is adhered, and after solidifying t-butanol on the substrate to form a solidified body, the solidified body is sublimated. A drying technique that removes them is disclosed.

JP 2013-16699 A JP 2012-243869 A JP 2013-258272 A JP, 2015-142069, A

  However, even with the drying techniques disclosed in Patent Documents 1 to 4, for example, for a substrate having a pattern that is fine and has a high aspect ratio (that is, the height of the convex pattern is higher than the width of the convex pattern), There is a problem that collapse of a sufficient pattern cannot be sufficiently prevented. There are various causes for the occurrence of pattern collapse. One of them is a force acting between a solidified body made of a sublimable substance and the pattern surface. At the interface between the pattern surface and the solidified body, forces such as ionic bonds, hydrogen bonds, and van der Waals act between the molecules constituting the pattern and the sublimation substances constituting the solidified body.

  Therefore, even if the solidified body changes to a gas state without passing through a liquid state, if sublimation proceeds non-uniformly, stress is applied to the pattern, and the pattern collapses. In addition, the force acting between the solidified body and the pattern surface greatly depends on the physical properties of the sublimable substance constituting the solidified body. Therefore, in order to eliminate pattern collapse in sublimation drying on a fine pattern surface, it is necessary to select a sublimable material more suitable for sublimation drying.

  The present invention has been made in view of the above problems, and provides a substrate processing apparatus and a substrate processing method capable of removing a liquid adhering to a surface of a substrate while preventing a pattern formed on the surface of the substrate from collapsing. The purpose is to provide.

  In order to solve the above problems, a substrate processing apparatus according to the present invention includes a supply means for supplying a processing liquid containing a sublimable substance in a molten state to a pattern forming surface of a substrate, A vapor pressure at 20 ° C. to 25 ° C. of the sublimable substance, comprising: a solidification unit that solidifies on a surface to form a solidified body; and a sublimation unit that sublimates the solidified body and removes the solidified body from the pattern forming surface. Is 5 kPa or more, and the surface tension at 20 ° C. to 25 ° C. is 25 mN / m or less.

  According to the above configuration, for example, when a liquid is present on the pattern forming surface of the substrate, the liquid can be removed while preventing the pattern from collapsing by the principle of freeze drying (or sublimation drying). Specifically, the supply unit supplies the processing liquid to the pattern forming surface of the substrate, thereby replacing the liquid with the processing liquid. Next, the solidification means solidifies the treatment liquid to form a solidified body. Here, by using a sublimable substance having a vapor pressure of 5 kPa or more and a surface tension of 25 mN / m or less (both values in a temperature range of 20 ° C. to 25 ° C.), When sublimating, the degree of progress of sublimation can be reduced. Thereby, compared with the case where sublimation advances nonuniformly, the stress added to the pattern of a board | substrate can be reduced. As a result, for example, the occurrence of pattern collapse can be reduced even in a substrate having a pattern surface having a fine aspect ratio, as compared with a substrate processing apparatus using a conventional sublimable substance such as t-butanol.

  Here, the “melted state” means a state in which the sublimable substance is fluid or liquid by melting completely or partially. The “sublimation” means that a single substance, a compound or a mixture has a property of undergoing a phase transition from a solid to a gas or from a gas to a solid without passing through a liquid. It means a substance having such a sublimation property. Further, the “pattern forming surface” means a surface on which a concavo-convex pattern is formed in an arbitrary region on the substrate regardless of whether it is planar, curved, or concavo-convex. The "solidified body" is a solidified liquid processing solution. For example, when the liquid present on the substrate is mixed with the processing liquid and solidified by the solidifying means, The liquid may also be included.

  In the said structure, it is preferable that the surface tension in 20 to 25 degreeC of the said sublimable substance is 20 mN / m or less.

  In the above configuration, the sublimable substance is preferably 1,1,2,2,3,3,4-heptafluorocyclopentane or dodecafluorocyclohexane.

  Further, in the above configuration, the supply means supplies the processing liquid to the pattern forming surface of the substrate under atmospheric pressure, and the solidifying means sublimates the processing liquid under atmospheric pressure. It is preferable that it is cooled below the freezing point of the active substance. Thereby, at least the supply means and the coagulation means do not need to have a pressure resistant structure, and the apparatus cost can be reduced.

  In the above structure, the sublimable substance preferably has sublimability under atmospheric pressure, and the sublimation means preferably sublimates the sublimable substance under atmospheric pressure. As a result, by using a sublimable substance that has sublimability under atmospheric pressure, at least in the sublimation means, there is no need to have a pressure resistant structure, and the apparatus cost can be reduced. .

  Further, in the above configuration, at least one of the solidifying means and the sublimation means directs the refrigerant to the back surface of the substrate opposite to the pattern forming surface at a temperature not higher than the freezing point of the sublimable substance. It can be set as the refrigerant | coolant supply means supplied.

  According to the above configuration, in the solidification means, the sublimation substance is cooled and solidified by supplying a refrigerant below the freezing point of the sublimation substance toward the back surface opposite to the pattern forming surface of the substrate. It becomes possible to make it. Further, in the sublimation means, by supplying the coolant toward the back surface of the substrate, the solidified body can be naturally sublimated while preventing the solidified body from melting from the back surface side of the substrate. Furthermore, when both the solidifying means and the sublimation means are configured so that the coolant can be supplied to the back surface of the substrate, the number of parts can be reduced, and the apparatus cost can be reduced.

  Further, in the above configuration, at least one of the solidifying means and the sublimation means includes at least a gas inert to the sublimable substance at a temperature below the freezing point of the sublimable substance. It can be set as the gas supply means supplied toward.

  According to the above configuration, the gas supply means supplies, as the solidification means, an inert gas having a temperature equal to or lower than the freezing point of the sublimable substance toward the pattern formation surface, so that the sublimable substance is cooled and solidified. It becomes possible to make it. The gas supply means can also sublimate the solidified body formed on the pattern formation surface by supplying an inert gas, and can function as a sublimation means. Furthermore, since the gas supply means can be used in combination with the coagulation means and the sublimation means, the number of parts can be reduced and the apparatus cost can be reduced. Note that since the inert gas is inert to the sublimable substance, the sublimable substance is not denatured.

  In the above configuration, the sublimation means includes a gas supply means for supplying a gas inert to at least the sublimable substance toward the pattern forming surface at a temperature below the freezing point of the sublimation substance. The coolant supply means may supply the coolant toward the back surface of the substrate opposite to the pattern formation surface at a temperature equal to or lower than the freezing point of the sublimable substance.

  According to said structure, with respect to the solidified body currently formed in the pattern formation surface, a gas supply means sublimates the said solidified body by supplying an inert gas at the temperature below the freezing point of a sublimable substance. . In addition, for the back surface of the substrate opposite to the pattern formation surface, the coolant supply means prevents the solidified body from melting from the back surface side of the substrate by supplying the coolant at a temperature below the freezing point of the sublimable substance. can do.

  In the above configuration, the sublimation means is preferably a decompression means for decompressing the pattern forming surface on which the solidified body is formed in an environment lower than atmospheric pressure.

  By using the decompression means as the sublimation means, the pattern forming surface of the substrate can be placed in an environment lower than atmospheric pressure, and the sublimable substance in the solidified body can be sublimated. Here, when the sublimable substance sublimates from the solidified body and vaporizes, the solidified body is deprived of heat as sublimation heat. Therefore, the solidified body is cooled. Therefore, even under a temperature environment slightly higher than the melting point of the sublimable substance, the solidified body can be maintained at a lower temperature than the melting point of the sublimable substance without separately cooling. As a result, the solidified body can be sublimated while preventing the melting of the sublimable substance in the solidified body. In addition, since it is not necessary to provide a separate cooling mechanism, apparatus cost and processing cost can be reduced.

  In the above configuration, it is preferable that the coagulating unit is a depressurizing unit that depressurizes the pattern forming surface supplied with the processing liquid in an environment lower than atmospheric pressure.

  According to the above configuration, by using the pressure reducing means as the solidifying means, the processing liquid is evaporated under the environment where the pattern forming surface of the substrate is lower than the atmospheric pressure, and the processing liquid is cooled by the heat of vaporization. A solidified body can be formed. In addition, since it is not necessary to provide a separate cooling mechanism, apparatus cost and processing cost can be reduced.

  Moreover, in the said structure, it is preferable to use the said pressure reduction means as said sublimation means. According to this configuration, since the decompression means used as the coagulation means is also used as the sublimation means, the number of parts can be reduced, and the device cost can be reduced.

  In the above configuration, it is preferable that the supply unit includes a processing liquid temperature adjusting unit that adjusts the temperature of the processing liquid to a temperature equal to or higher than the melting point of the sublimable substance and lower than the boiling point. According to said structure, the said supply means can further be equipped with a process liquid temperature adjustment part, and can adjust the temperature of a process liquid to the temperature more than melting | fusing point of a sublimable substance and lower than a boiling point. By setting the temperature of the treatment liquid to be equal to or higher than the melting point of the sublimable substance, the liquid on the substrate can be favorably dried while further preventing the pattern formed on the substrate from collapsing.

  In order to solve the above-described problems, the substrate processing method of the present invention provides a supply method for supplying a processing liquid containing a sublimable substance in a molten state to the pattern forming surface of the substrate, and the processing liquid is supplied to the pattern forming surface. A vapor pressure of 5 kPa at 20 ° C. to 25 ° C. of the sublimable substance, including a solidification method in which the solidified body is solidified to form a solidified body and a sublimation method in which the solidified body is sublimated and removed from the pattern forming surface. The surface tension at 20 ° C. to 25 ° C. is 25 mN / m or less.

  According to the above configuration, for example, when a liquid is present on the pattern forming surface of the substrate, the liquid can be removed while preventing the pattern from collapsing by the principle of freeze drying (or sublimation drying). Specifically, in the supplying step, the liquid is replaced with the processing liquid by supplying the processing liquid to the pattern forming surface of the substrate. Next, in the solidification step, the treatment liquid is solidified to form a solidified body. Here, by using a sublimable substance having a vapor pressure of 5 kPa or more and a surface tension of 25 mN / m or less (both values in a temperature range of 20 ° C. to 25 ° C.), in the sublimation process, When the sublimable substance is sublimated, the degree of progress of sublimation can be made uniform. Thereby, compared with the case where sublimation advances nonuniformly, the stress added to the pattern of a board | substrate can be reduced. As a result, for example, the occurrence of pattern collapse can be further reduced even in a substrate having a pattern surface having a fine aspect ratio, as compared with a substrate processing method using a conventional sublimable substance such as t-butanol. .

  In the said structure, it is preferable that the surface tension in 20 to 25 degreeC of the said sublimable substance is 20 mN / m or less.

  In the above configuration, the sublimable substance is preferably 1,1,2,2,3,3,4-heptafluorocyclopentane or dodecafluorocyclohexane.

The present invention has the following effects by the means described above.
That is, according to the present invention, for example, when a liquid is present on the pattern formation surface of the substrate, the liquid is replaced with a treatment liquid containing a sublimation substance, and then the treatment liquid is solidified to form a solidified body. After that, the sublimable substance in the solidified body is sublimated, and the liquid on the substrate is dried. Here, in the present invention, as a sublimable substance, a substance having a vapor pressure (20 ° C. to 25 ° C.) of 5 kPa or more and a surface tension (20 ° C. to 25 ° C.) of 25 mN / m or less is used. During the sublimation of the substance, the progress of sublimation can be made uniform. Thereby, in this invention, it can reduce that stress is added to a pattern resulting from the non-uniform progression of sublimation. As a result, the present invention can further reduce pattern collapse as compared with a substrate processing apparatus and a substrate processing method using a conventional sublimable substance such as t-butanol. Very suitable for drying process.

It is explanatory drawing showing the outline of the substrate processing apparatus which concerns on 1st Embodiment of this invention. It is a schematic plan view showing the said substrate processing apparatus. FIG. 3A is a block diagram illustrating a schematic configuration of a drying auxiliary liquid storage unit in the substrate processing apparatus, and FIG. 3B is an explanatory diagram illustrating a specific configuration of the drying auxiliary liquid storage unit. . It is a block diagram which shows schematic structure of the gas tank in the said substrate processing apparatus. It is a block diagram which shows schematic structure of the refrigerant | coolant storage part in the said substrate processing apparatus. It is explanatory drawing which shows schematic structure of the control unit in the said substrate processing apparatus. It is a flowchart which shows the substrate processing method using the said substrate processing apparatus. It is a figure which shows the mode of the board | substrate in each process of the said substrate processing method. It is a flowchart which shows the substrate processing method which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the substrate processing method which concerns on 3rd Embodiment of this invention. It is a SEM image showing the pattern formation surface of the untreated silicon substrate used by the Example and comparative example of this invention. It is a SEM image showing the pattern formation surface of the silicon substrate which performed the substrate processing based on Example 1 of this invention. It is a SEM image showing the pattern formation surface of the silicon substrate which performed the board | substrate process which concerns on Example 2 of this invention. 6 is an SEM image showing a pattern formation surface of a silicon substrate subjected to substrate processing according to Comparative Example 1; It is a SEM image showing the pattern formation surface of the silicon substrate which performed the substrate processing which concerns on the comparative example 2. FIG. It is a SEM image showing the pattern formation surface of the silicon substrate which performed the substrate processing concerning the comparative example 3. It is a SEM image showing the pattern formation surface of the silicon substrate which performed the substrate processing which concerns on the comparative example 4. FIG. 10 is an SEM image showing a pattern formation surface of a silicon substrate subjected to substrate processing according to Comparative Example 5.

(First embodiment)
A first embodiment of the present invention will be described below.
FIG. 1 is an explanatory diagram showing an outline of a substrate processing apparatus 1 according to this embodiment. FIG. 2 is a schematic plan view showing the internal configuration of the substrate processing apparatus 1. In each figure, XYZ orthogonal coordinate axes are appropriately displayed in order to clarify the directional relationship between the illustrated ones. 1 and 2, the XY plane represents a horizontal plane, and the tens Z direction represents a vertically upward direction.

  The substrate processing apparatus 1 can be used, for example, for processing various substrates. The “substrate” means a semiconductor substrate, a glass substrate for photomask, a glass substrate for liquid crystal display, a glass substrate for plasma display, a substrate for FED (Field Emission Display), an optical disk substrate, a magnetic disk substrate, and a magneto-optical disk. It refers to various substrates such as substrates. In the present embodiment, a case where the substrate processing apparatus 1 is used for processing a semiconductor substrate (hereinafter referred to as “substrate W”) will be described as an example.

  Further, as an example of the substrate W, a circuit pattern or the like (hereinafter referred to as “pattern”) is formed only on one main surface. Here, the pattern forming surface (main surface) on which the pattern is formed is referred to as “front surface”, and the main surface on which the pattern on the opposite side is not formed is referred to as “back surface”. Further, the surface of the substrate directed downward is referred to as “lower surface”, and the surface of the substrate directed upward is referred to as “upper surface”. In the following description, the upper surface is the surface.

  Moreover, it does not specifically limit as a shape of the said pattern, For example, a line shape or a cylindrical shape is mentioned. Moreover, it does not specifically limit as a magnitude | size of a pattern, It can set arbitrarily arbitrarily. Furthermore, the material of the pattern is not particularly limited, and examples thereof include metals and insulating materials.

  The substrate processing apparatus 1 is a single-wafer type substrate processing apparatus used for a cleaning process (including a rinsing process) for removing contaminants such as particles adhering to the substrate W, and a drying process after the cleaning process. It is. 1 and 2 show only a portion used for the drying process, and a cleaning nozzle or the like used for the cleaning process is not shown, but the substrate processing apparatus 1 may include the nozzle or the like. .

<1-1 Configuration of Substrate Processing Apparatus>
First, the configuration of the substrate processing apparatus 1 will be described with reference to FIGS. 1 and 2.
The substrate processing apparatus 1 is held by a chamber 11 that is a container for containing a substrate W, a substrate holding unit 51 that holds the substrate W, a control unit 13 that controls each part of the substrate processing apparatus 1, and a substrate holding unit 51. A processing liquid supply means (supply means) 21 for supplying a processing liquid as a drying auxiliary liquid to the substrate W, and an IPA supply means 31 for supplying IPA (isopropyl alcohol) to the substrate W held by the substrate holding means 51; The gas is supplied to the gas supply means 41 (coagulation means, sublimation means) for supplying gas to the substrate W held by the substrate holding means 51 and the substrate W held by the substrate holding means 51 and discharged to the outside of the recording part of the substrate W. The anti-scattering cup 12 that collects the IPA, the drying auxiliary liquid, and the like, the turning drive unit 14 that individually turns the later-described arms of each part of the substrate processing apparatus 1, and the chamber 11 Comprising at least a pressure reducing means 71 for reducing the internal pressure, coolant supply means (coagulation means, sublimation means) for supplying coolant to the back surface Wb of the substrate W and 81. Further, the substrate processing apparatus 1 includes a substrate carry-in / out means, a chuck pin opening / closing mechanism, and a wet cleaning means (all not shown). Each part of the substrate processing apparatus 1 will be described below.

  The substrate holding means 51 includes a rotation driving unit 52, a spin base 53, and a chuck pin 54. The spin base 53 has a slightly larger planar size than the substrate W. Near the periphery of the spin base 53, a plurality of chuck pins 54 that hold the periphery of the substrate W are provided upright. The number of chuck pins 54 is not particularly limited, but it is preferable that at least three chuck pins 54 are provided in order to securely hold the circular substrate W. In the present embodiment, three are arranged at equal intervals along the peripheral edge of the spin base 53 (see FIG. 2). Each chuck pin 54 includes a substrate support pin that supports the peripheral portion of the substrate W from below, and a substrate holding pin that holds the substrate W by pressing the outer peripheral end surface of the substrate W supported by the substrate support pin.

  Each chuck pin 54 can be switched between a pressing state in which the substrate holding pin presses the outer peripheral end surface of the substrate W and a released state in which the substrate holding pin is separated from the outer peripheral end surface of the substrate W. State switching is executed in accordance with an operation command from the control unit 13 to be controlled.

  More specifically, when the substrate W is carried into and out of the spin base 53, each chuck pin 54 is released, and when the substrate W is subjected to substrate processing from cleaning processing to sublimation processing described later. Each chuck pin 54 is in a pressed state. When the chuck pin 54 is in a pressed state, the chuck pin 54 grips the peripheral edge of the substrate W, and the substrate W is held in a horizontal posture (XY plane) at a predetermined interval from the spin base 53. As a result, the substrate W is held horizontally with its surface Wf facing upward.

  As described above, in this embodiment, the substrate W is held by the spin base 53 and the chuck pins 54, but the substrate holding method is not limited to this. For example, the back surface Wb of the substrate W may be held by a suction method such as a spin chuck.

  The spin base 53 is connected to the rotation drive unit 52. The rotation driving unit 52 rotates around the axis Al along the Z direction according to the operation command of the control unit 13. The rotation drive unit 52 includes a known belt, a motor, and a rotation shaft. When the rotation driving unit 52 rotates around the axis Al, the substrate W held by the chuck pins 54 above the spin base 53 rotates around the axis Al together with the spin base 53.

Next, the processing liquid supply means (supply means) 21 will be described.
The processing liquid supply means 21 is a unit that supplies the drying auxiliary liquid to the pattern forming surface of the substrate W. As shown in FIG. 1, the nozzle 22, the arm 23, the turning shaft 24, the pipe 25, and the valve 26 are provided. And at least a treatment liquid reservoir 27.

  As illustrated in FIGS. 3A and 3B, the processing liquid storage unit 27 includes a processing liquid storage tank 271, a stirring unit 277 that stirs the drying auxiliary liquid in the processing liquid storage tank 271, and a processing liquid. A pressurization unit 274 that pressurizes the storage tank 271 to send out the dry auxiliary liquid and a temperature adjustment unit 272 that heats the dry auxiliary liquid in the treatment liquid storage tank 271 are provided. FIG. 3A is a block diagram illustrating a schematic configuration of the processing liquid storage unit 27, and FIG. 3B is an explanatory diagram illustrating a specific configuration of the processing liquid storage unit 27.

  The stirring unit 277 includes a rotating unit 279 that stirs the drying auxiliary liquid in the processing liquid storage tank 271 and a stirring control unit 278 that controls the rotation of the rotating unit 279. The stirring control unit 278 is electrically connected to the control unit 13. The rotating unit 279 is provided with a propeller-like stirring blade at the tip of the rotating shaft (the lower end of the rotating unit 279 in FIG. 4). The control unit 13 issues an operation command to the stirring control unit 278, and the rotating unit 279 By rotating, the stirring blade stirs the drying auxiliary liquid and makes the concentration and temperature of the drying auxiliary substance and the like in the drying auxiliary liquid uniform.

  Further, the method for making the concentration and temperature of the drying auxiliary liquid in the processing liquid storage tank 271 uniform is not limited to the above-described method, and a known method such as a method of separately circulating a drying auxiliary liquid by providing a circulation pump. The method can be used.

  The pressurizing unit 274 includes a nitrogen gas tank 275 that is a gas supply source that pressurizes the inside of the processing liquid storage tank 271, a pump 276 that pressurizes the nitrogen gas, and a pipe 273. The nitrogen gas tank 275 is connected to the processing liquid storage tank 271 through a pipe 273, and a pump 276 is inserted in the pipe 273.

  The temperature adjusting unit 272 is electrically connected to the control unit 13, and adjusts the temperature by heating the drying auxiliary liquid stored in the processing liquid storage tank 271 according to an operation command of the control unit 13. The temperature adjustment may be performed so that the temperature of the drying auxiliary liquid becomes equal to or higher than the melting point of the drying auxiliary substance (sublimation substance, details will be described later) contained in the drying auxiliary liquid. Thereby, the melting state of the drying auxiliary substance can be maintained. In addition, as an upper limit of temperature control, it is preferable that it is temperature lower than a boiling point. Moreover, it does not specifically limit as the temperature adjustment part 272, For example, a well-known temperature adjustment mechanism, such as a resistance heater, a Peltier device, piping through which the temperature adjusted water was passed, can be used. In the present embodiment, the temperature adjustment unit 272 has an arbitrary configuration. For example, when the installation environment of the substrate processing apparatus 1 is in an environment higher than the melting point of the sublimable substance, the melting state of the sublimable substance can be maintained, and thus heating of the drying auxiliary liquid becomes unnecessary. . As a result, the temperature adjustment unit 272 can be omitted.

  Returning to FIG. The processing liquid storage unit 27 (more specifically, the processing liquid storage tank 271) is connected to the nozzle 22 via a pipe 25, and a valve 26 is inserted in the path of the pipe 25.

  An atmospheric pressure sensor (not shown) is provided in the processing liquid storage tank 271 and is electrically connected to the control unit 13. The control unit 13 controls the operation of the pump 276 based on the value detected by the atmospheric pressure sensor, thereby maintaining the atmospheric pressure in the processing liquid storage tank 271 at a predetermined atmospheric pressure higher than the atmospheric pressure. On the other hand, the valve 26 is also electrically connected to the control unit 13 and is normally closed. The opening / closing of the valve 26 is also controlled by an operation command from the control unit 13. When the control unit 13 issues an operation command to the processing liquid supply means 21 and opens the valve 26, the drying auxiliary liquid is pumped from the pressurized processing liquid storage tank 271, and the nozzle 22 is connected via the pipe 25. It is discharged from. Thereby, the drying auxiliary liquid can be supplied to the surface Wf of the substrate W. The treatment liquid storage tank 271 is preferably configured to be airtight because the drying auxiliary liquid is pumped using the pressure of nitrogen gas as described above.

  The nozzle 22 is attached to the tip of an arm 23 that extends horizontally, and is disposed above the spin base 53. The rear end portion of the arm 23 is rotatably supported around the axis J <b> 1 by a pivot shaft 24 extending in the Z direction, and the pivot shaft 24 is fixed in the chamber 11. The arm 23 is connected to the turning drive unit 14 via the turning shaft 24. The turning drive unit 14 is electrically connected to the control unit 13 and rotates the arm 23 around the axis J1 according to an operation command from the control unit 13. As the arm 23 rotates, the nozzle 22 also moves.

  As shown by a solid line in FIG. 2, the nozzle 22 is usually disposed at the retracted position P <b> 1 outside the peripheral edge of the substrate W and outside the scattering prevention cup 12. When the arm 23 is rotated by an operation command from the control unit 13, the nozzle 22 moves along the path indicated by the arrow AR1, and is disposed at a position above the central portion (axis A1 or the vicinity thereof) of the surface Wf of the substrate W.

  Returning to FIG. Next, the IPA supply means 31 will be described. The IPA supply means 31 is a unit that supplies IPA to the substrate W, and includes a nozzle 32, an arm 33, a turning shaft 34, a pipe 35, a valve 36, and an IPA tank 37.

  The IPA tank 37 is connected to the nozzle 32 via a pipe 35, and a valve 36 is inserted in the path of the pipe 35. IPA is stored in the IPA tank 37, and the IPA in the IPA tank 37 is pressurized by a pressurizing unit (not shown), and the IPA is sent from the pipe 35 toward the nozzle 32.

  The valve 36 is electrically connected to the control unit 13 and is normally closed. The opening / closing of the valve 36 is controlled by an operation command of the control unit 13. When the valve 36 is opened by the operation command of the control unit 13, IPA is supplied from the nozzle 32 to the surface Wf of the substrate W through the pipe 35.

  The nozzle 32 is attached to the tip of an arm 33 that extends horizontally, and is disposed above the spin base 53. A rear end portion of the arm 33 is rotatably supported around the axis J <b> 2 by a pivot shaft 34 extending in the Z direction, and the pivot shaft 34 is fixed in the chamber 11. The arm 33 is connected to the turning drive unit 14 via the turning shaft 34. The turning drive unit 14 is electrically connected to the control unit 13 and rotates the arm 33 around the axis J2 according to an operation command from the control unit 13. As the arm 33 rotates, the nozzle 32 also moves.

  As indicated by a solid line in FIG. 2, the nozzle 32 is normally disposed outside the peripheral edge of the substrate W and at the retracted position P <b> 2 outside the scattering prevention cup 12. When the arm 33 is rotated by an operation command from the control unit 13, the nozzle 32 moves along the path indicated by the arrow AR2, and is disposed at a position above the central portion (axis A1 or the vicinity thereof) of the surface Wf of the substrate W.

  In the present embodiment, IPA is used in the IPA supply means 31, but the present invention may be any liquid that has solubility in a dry auxiliary substance and deionized water (DIW). Not limited to. As an alternative to IPA in the present embodiment, methanol, ethanol, acetone, benzene, carbon tetrachloride, chloroform, hexane, decalin, tetralin, acetic acid, cyclohexanol, ether, hydrofluoroether, etc. Can be mentioned.

  Returning to FIG. Next, the gas supply means 41 will be described. The gas supply means 41 is a unit that supplies gas to the substrate W, and includes a nozzle 42, an arm 43, a turning shaft 44, a pipe 45, a valve 46, and a gas tank 47.

  FIG. 4 is a block diagram showing a schematic configuration of the gas tank 47. The gas tank 47 includes a gas storage unit 471 that stores gas and a gas temperature adjustment unit 472 that adjusts the temperature of the gas stored in the gas storage unit 471. The gas temperature adjustment unit 472 is electrically connected to the control unit 13, and adjusts the temperature by heating or cooling the gas stored in the gas storage unit 471 according to an operation command of the control unit 13. Temperature adjustment should just be performed so that the gas stored in the gas storage part 471 may become the low temperature below the freezing point of a drying auxiliary substance.

  The gas temperature adjusting unit 472 is not particularly limited, and for example, a known temperature adjusting mechanism such as a Peltier element or a pipe through which water whose temperature has been adjusted can be used.

  Returning to FIG. The gas tank 47 (more specifically, the gas storage unit 471) is connected to the nozzle 42 via a pipe 45, and a valve 46 is inserted in the middle of the path of the pipe 45. The gas in the gas tank 47 is pressurized by a pressurizing means (not shown) and sent to the pipe 45. The pressurizing means can be realized by compressing and storing gas in the gas tank 47 in addition to pressurization by a pump or the like, and any pressurizing means may be used.

  The valve 46 is electrically connected to the control unit 13 and is normally closed. The opening / closing of the valve 46 is controlled by an operation command of the control unit 13. When the valve 46 is opened by an operation command of the control unit 13, gas is supplied from the nozzle 42 to the surface Wf of the substrate W through the pipe 45.

  The nozzle 42 is attached to the tip of an arm 43 that extends horizontally, and is disposed above the spin base 53. The rear end portion of the arm 43 is rotatably supported around the axis J3 by a pivot shaft 44 extending in the Z direction, and the pivot shaft 44 is fixed in the chamber 11. The arm 43 is connected to the turning drive unit 14 via the turning shaft 44. The turning drive unit 14 is electrically connected to the control unit 13 and rotates the arm 43 about the axis J3 according to an operation command from the control unit 13. As the arm 43 rotates, the nozzle 42 also moves.

  As indicated by a solid line in FIG. 2, the nozzle 42 is normally disposed outside the peripheral edge of the substrate W and at the retracted position P <b> 3 outside the scattering prevention cup 12. When the arm 43 is rotated by the operation command of the control unit 13, the nozzle 42 moves along the path indicated by the arrow AR3, and is disposed at a position above the central portion (axis A1 or the vicinity thereof) of the surface Wf of the substrate W. A state in which the nozzle 42 is arranged at a position above the center of the surface Wf is indicated by a dotted line in FIG.

  The gas storage unit 471 stores at least a gas inert to the drying auxiliary substance, more specifically nitrogen gas. The stored nitrogen gas is adjusted to a temperature not higher than the freezing point of the drying auxiliary substance in the gas temperature adjusting unit 472. Although the temperature of nitrogen gas will not be specifically limited if it is the temperature below the freezing point of a drying auxiliary substance, Usually, it can set in the range of 0 degreeC or more and 15 degrees C or less. Note that by setting the temperature of the nitrogen gas to 0 ° C. or higher, the water vapor present in the chamber 11 is prevented from solidifying and adhering to the surface Wf of the substrate W, thereby preventing adverse effects on the substrate W. can do.

  The nitrogen gas used in the first embodiment is preferably a dry gas having a dew point of 0 ° C. or lower. When the nitrogen gas is blown onto the solidified body under an atmospheric pressure environment, the drying auxiliary substance in the solidified body sublimes in the nitrogen gas. Since nitrogen gas continues to be supplied to the solidified body, the partial pressure in the nitrogen gas of the gaseous dry auxiliary substance generated by sublimation is higher than the saturated vapor pressure of the gaseous dry auxiliary substance at the temperature of the nitrogen gas. It is maintained in a low state, and at least on the surface of the solidified body, it is filled in an atmosphere in which a gaseous dry auxiliary substance is present below its saturated vapor pressure.

  In the present embodiment, nitrogen gas is used as the gas supplied by the gas supply means 41. However, the implementation of the present invention is not limited to this as long as the gas is inert with respect to the dry auxiliary substance. In the first embodiment, examples of a gas that can replace nitrogen gas include argon gas, helium gas, and dry air (a gas having a nitrogen gas concentration of 80% and an oxygen gas concentration of 20%). Or the mixed gas which mixed these multiple types of gas may be sufficient.

  Returning to FIG. The decompression unit 71 is a unit that decompresses the interior of the chamber 11 to an environment lower than the atmospheric pressure, and includes an exhaust pump 72, a pipe 73, and a valve 74. The exhaust pump 72 is a known pump that is connected to the chamber 11 via a pipe 73 and applies pressure to the gas. The exhaust pump 72 is electrically connected to the control unit 13 and is normally stopped. The driving of the exhaust pump 72 is controlled by an operation command of the control unit 13. A valve 74 is inserted into the pipe 73. The valve 74 is electrically connected to the control unit 13 and is normally closed. Opening and closing of the valve 74 is controlled by an operation command of the control unit 13.

  When the exhaust pump 72 is driven by the operation command of the control unit 13 and the valve 74 is opened, the gas existing inside the chamber 11 is exhausted to the outside of the chamber 11 through the pipe 73 by the exhaust pump 72. .

  The anti-scattering cup 12 is provided so as to surround the spin base 53. The anti-scattering cup 12 is connected to an elevating drive mechanism (not shown) and can elevate in the Z direction. When supplying the drying auxiliary liquid or IPA to the substrate W, the scattering prevention cup 12 is positioned at a predetermined position as shown in FIG. 1 by the elevating drive mechanism, and the substrate W held by the chuck pin 54 is moved from the lateral position. surround. Thereby, liquids, such as drying auxiliary liquid and IPA which scatter from the board | substrate W or the spin base 53, can be collected.

Next, the refrigerant supply means 81 will be described.
The refrigerant supply means 81 is a unit that supplies a refrigerant to the back surface Wb of the substrate W, and includes at least a refrigerant reservoir 82, a pipe 83, a valve 84, and a refrigerant supply pipe 85, as shown in FIG.

  FIG. 5 is a block diagram illustrating a schematic configuration of the refrigerant reservoir 82. The refrigerant storage unit 82 includes a refrigerant tank 821 that stores the refrigerant, and a refrigerant temperature adjustment unit 822 that adjusts the temperature of the refrigerant stored in the refrigerant tank 821.

  The refrigerant temperature adjustment unit 822 is electrically connected to the control unit 13, and adjusts the temperature by heating or cooling the refrigerant stored in the refrigerant tank 821 according to an operation command of the control unit 13. The temperature adjustment may be performed so that the refrigerant stored in the refrigerant tank 821 has a low temperature below the freezing point of the drying auxiliary substance. In addition, it does not specifically limit as the refrigerant temperature adjustment part 822, For example, a well-known temperature adjustment mechanism etc., such as a chiller using a Bercher element, piping through which water adjusted temperature, etc. can be used.

  Returning to FIG. The refrigerant reservoir 82 is connected to a refrigerant supply pipe 85 via a pipe 83, and a valve 84 is inserted midway along the pipe 83. The refrigerant supply pipe 85 is provided by forming a through hole in the central portion of the spin base 53. The refrigerant in the refrigerant reservoir 82 is pressurized by pressure means (not shown) and sent to the pipe 82. The pressurizing means can be realized not only by pressurization by a pump or the like but also by compressing and storing gas in the refrigerant storage section 82, and therefore any pressurizing means may be used.

  The valve 84 is electrically connected to the control unit 13 and is normally closed. The opening / closing of the valve 84 is controlled by an operation command of the control unit 13. When the valve 84 is opened by the operation command of the control unit 13, the refrigerant is supplied to the back surface Wb of the substrate W through the pipe 83 and the refrigerant supply pipe 85.

  As said refrigerant | coolant, the liquid or gas below the freezing point of a drying auxiliary substance is mentioned. Furthermore, it does not specifically limit as said liquid, For example, 7 degreeC cold water etc. are mentioned. Moreover, it does not specifically limit as said gas, For example, the gas inert to a dry auxiliary substance, More specifically, 7 degreeC nitrogen gas etc. are mentioned.

  FIG. 6 is a schematic diagram showing the configuration of the control unit 13. The control unit 13 is electrically connected to each part of the substrate processing apparatus 1 (see FIG. 1), and controls the operation of each part. The control unit 13 is configured by a computer having an arithmetic processing unit 15 and a memory 17. As the arithmetic processing unit 15, a CPU that performs various arithmetic processes is used. The memory 17 includes a ROM that is a read-only memory that stores basic programs, a RAM that is a readable and writable memory that stores various types of information, and a magnetic disk that stores control software and data. Substrate processing conditions (recipe) corresponding to the substrate W are stored in advance in the magnetic disk. The CPU reads the substrate processing program into the RAM, and the CPU controls each unit of the substrate processing apparatus 1 according to the contents.

<1-2 Drying auxiliary liquid>
Next, the drying auxiliary liquid used in this embodiment will be described below.
The drying auxiliary liquid of this embodiment is a processing liquid containing a molten drying auxiliary substance (sublimation substance). In the drying process for removing the liquid present on the pattern forming surface of the substrate, the drying process is performed. It fulfills the function of assisting. In addition, the sublimable substance has a property of undergoing phase transition from a solid to a gas or from a gas to a solid without passing through a liquid. Since the sublimable substance is contained in the dry auxiliary liquid in a molten state, a film-like solidified body having a uniform layer thickness can be formed on the substrate W.

In this embodiment, the vapor pressure of the sublimable substance in the range of 20 ° C. to 25 ° C. is 5 kPa or more, preferably 8 kPa or more and 100 kPa or less, more preferably 15 kPa or more and 100 kPa or less. The surface tension of the sublimable substance at 20 ° C. to 25 ° C. is 25 mN / m or less, preferably 20 mN / m or less, more preferably greater than 0 mN / m and 15 mN / m or less, and even more preferably 0 mN / m to 13 mN / m. By using a sublimable substance having a vapor pressure of 5 kPa or more and a surface tension of 25 mN / m or less, the progress of sublimation of the sublimable substance in the solidified body is suppressed and the pattern collapses. Can be reduced. For example, for a pattern in which a plurality of cylinders (aspect ratio 16) having a diameter of 30 nm and a height of 480 nm are arranged on the substrate with an interval of 80 nm, the pattern collapse rate is suppressed to 20% or less. Can do. The pattern collapse rate is a value calculated by the following equation.
Pattern collapse rate (%) = (number of collapsed protrusions in an arbitrary area) ÷ (total number of protrusions in the area) × 100

  In the present embodiment, as the sublimable substance, for example, 1,1,2,2,3,3,4-heptafluorocyclopentane (vapor pressure at 20 ° C. 8.2 kPa, surface tension at 25 ° C. 19. 6 mN / m, melting point 20.5 ° C.), dodecafluorocyclohexane (vapor pressure 33.1 kPa at 20 ° C., surface tension 12.6 mN / m (calculated value) at 25 ° C., melting point 51 ° C.), etc. Can do. These sublimable substances have a vapor pressure of DIW (a vapor pressure of 2.3 kPa at 20 ° C.) or t-butanol (a vapor pressure at 20 ° C. of 4 kPa at 20 ° C.) and a surface tension of 19 at 19 ° C. .56 mN / m, melting point 25 ° C.), the sublimation process can be performed at a faster sublimation rate than before. In addition, these sublimable substances do not have OH groups and are less soluble in water than t-butanol, so that mixing with water remaining on the substrate W does not occur. As a result, no moisture remains between the patterns after sublimation.

  The drying auxiliary liquid may be composed only of a sublimable substance in a molten state, but may further contain an organic solvent. In this case, the content of the sublimable substance is preferably 60% by mass or more, and more preferably 95% by mass or more with respect to the total mass of the drying auxiliary liquid. The organic solvent is not particularly limited as long as it is compatible with the molten sublimable substance. Specifically, alcohol etc. are mentioned, for example.

<1-3 Substrate processing method>
Next, a substrate processing method using the substrate processing apparatus 1 of the present embodiment will be described below based on FIGS. FIG. 7 is a flowchart showing the operation of the substrate processing apparatus 1 according to the first embodiment. FIG. 8 is a schematic diagram showing the state of the substrate W in each step of FIG. Note that an uneven pattern Wp is formed on the substrate W by a previous process. The pattern Wp includes a convex portion Wp1 and a concave portion Wp2. In the present embodiment, the convex portion Wp1 has a height in the range of 100 to 600 nm and a width in the range of 10 to 50 nm. Further, the shortest distance between the two adjacent convex portions Wp1 (the shortest width of the concave portion Wp2) is in the range of 10 to 50 nm. The aspect ratio of the convex portion Wp1, that is, the value obtained by dividing the height by the width (height / width) is 10 to 20.

  Each of FIGS. 8A to 8E is processed in an atmospheric pressure environment unless otherwise specified. Here, the atmospheric pressure environment refers to an environment of 0.7 atmospheric pressure or higher and 1.3 atmospheric pressure or lower with a standard atmospheric pressure (1 atmospheric pressure, 1013 hPa) as a center. In particular, when the substrate processing apparatus 1 is disposed in a clean room that is at a positive pressure, the environment of the surface Wf of the substrate W is higher than 1 atmosphere.

  Please refer to FIG. First, an execution instruction of the substrate processing program 19 corresponding to a predetermined substrate W is given by the operator. Thereafter, in preparation for carrying the substrate W into the substrate processing apparatus 1, the control unit 13 issues an operation command and performs the following operations.

  The rotation of the rotation drive unit 52 is stopped, and the chuck pin 54 is positioned at a position suitable for delivery of the substrate W. Further, the valves 26, 36, 46 and 74 are closed, and the nozzles 22, 32 and 42 are positioned at the retracted positions Pl, P2 and P3, respectively. Then, the chuck pin 54 is opened by an opening / closing mechanism (not shown).

  When an unprocessed substrate W is loaded into the substrate processing apparatus 1 by a substrate loading / unloading mechanism (not shown) and placed on the chuck pins 54, the chuck pins 54 are closed by an opening / closing mechanism (not shown).

  After the unprocessed substrate W is held by the substrate holding means 51, a cleaning step S11 is performed on the substrate by a wet cleaning means (not shown). The cleaning step S11 includes a rinsing process for removing the cleaning liquid after supplying the cleaning liquid to the surface Wf of the substrate W for cleaning. The supply of the cleaning liquid (in the case of the rinsing process) is performed on the surface Wf of the substrate W that rotates at a constant speed around the axis A <b> 1 according to an operation command to the rotation driving unit 52 by the control unit 13. The cleaning liquid is not particularly limited, and examples thereof include SC-1 (a liquid containing ammonia, hydrogen peroxide solution, and water) and SC-2 (a liquid containing hydrochloric acid, hydrogen peroxide solution, and water). Moreover, it does not specifically limit as a rinse liquid, For example, DIW etc. are mentioned. The supply amounts of the cleaning liquid and the rinsing liquid are not particularly limited, and can be set as appropriate according to the range to be cleaned. Further, the cleaning time is not particularly limited, and can be set as necessary.

  In the present embodiment, SC-1 is supplied to the surface Wf of the substrate W by the wet cleaning means to clean the surface Wf, and then DIW is further supplied to the surface Wf. Remove.

  FIG. 8A shows the state of the substrate W at the end of the cleaning step S11. As shown in FIG. 8A, DIW (indicated by “60” in the drawing) supplied in the cleaning step S11 adheres to the surface Wf of the substrate W on which the pattern Wp is formed. .

  Returning to FIG. Next, an IPA rinsing step S12 for supplying IPA to the surface Wf of the substrate W to which the DIW 60 is attached is performed. First, the control unit 13 issues an operation command to the rotation driving unit 52 to rotate the substrate W around the axis A1 at a constant speed.

  Next, the control unit 13 issues an operation command to the turning drive unit 14 to position the nozzle 32 at the center of the surface Wf of the substrate W. Then, the control unit 13 issues an operation command to the valve 36 and opens the valve 36. Thereby, IPA is supplied from the IPA tank 37 to the surface Wf of the substrate W through the pipe 35 and the nozzle 32.

  The IPA supplied to the surface Wf of the substrate W flows from the vicinity of the center of the surface Wf of the substrate W toward the peripheral portion of the substrate W due to the centrifugal force generated by the rotation of the substrate W. It spreads over the entire surface. Thereby, DIW adhering to the surface Wf of the substrate W is removed by supplying IPA, and the entire surface Wf of the substrate W is covered with IPA. The rotation speed of the substrate W is preferably set so that the film thickness of the IPA film is higher than the height of the projection Wp1 over the entire surface Wf. The supply amount of IPA is not particularly limited and can be set as appropriate.

  After completion of the IPA rinsing step S12, the control unit 13 issues an operation command to the valve 36 to close the valve 36. Further, the control unit 13 issues an operation command to the turning drive unit 14 to position the nozzle 32 at the retracted position P2.

  FIG. 8B shows the state of the substrate W at the end of the IPA rinsing step S12. As shown in FIG. 8B, the IPA supplied in the IPA rinsing step S12 (shown as “61” in the drawing) adheres to the surface Wf of the substrate W on which the pattern Wp is formed. The DIW 60 is replaced by the IPA 61 and removed from the surface Wf of the substrate W.

  Returning to FIG. Next, a treatment liquid supply step (supply step) S13 is performed for supplying a treatment liquid as a dry auxiliary liquid containing a dry auxiliary substance in a molten state to the surface Wf of the substrate W to which the IPA 61 is attached. First, the control unit 13 issues an operation command to the rotation drive unit 52 to rotate the substrate W around the axis Al at a constant speed. At this time, it is preferable that the rotation speed of the substrate W is set so that the film thickness of the liquid film made of the drying auxiliary liquid is higher than the height of the convex portion Wp1 on the entire surface Wf.

  Subsequently, the control unit 13 issues an operation command to the turning drive unit 14 to position the nozzle 22 at the center of the surface Wf of the substrate W. Then, the control unit 13 issues an operation command to the valve 26 and opens the valve 26. Thereby, the drying auxiliary liquid is supplied from the processing liquid storage tank 271 to the surface Wf of the substrate W through the pipe 25 and the nozzle 22.

  The temperature of the supplied drying auxiliary liquid is set in a range that is at least the melting point of the drying auxiliary substance and lower than the boiling point after being supplied to at least the surface Wf of the substrate W. For example, when 1,1,2,2,3,3,4-heptafluorocyclopentane (boiling point 82.5 ° C.) is used as a drying auxiliary substance, the temperature is set in the range of 35 ° C. or more and 82 ° C. or less. It is preferable. Moreover, the supply amount of the drying auxiliary liquid is not particularly limited, and can be set as appropriate.

  In this manner, by supplying the drying auxiliary liquid at a high temperature not lower than the melting point, a solidified body can be formed after the liquid film of the drying auxiliary liquid is formed on the surface Wf of the substrate W. As a result, a film-like solidified body having a uniform layer thickness can be obtained, and the occurrence of drying unevenness can be reduced. When the temperature of the substrate W and the atmospheric temperature in the chamber 11 are equal to or lower than the melting point of the drying auxiliary substance, if the drying auxiliary liquid having a temperature slightly higher than the melting point is supplied to the substrate W, the drying auxiliary liquid contacts the substrate W. Then it may solidify within a very short time. In such a case, a solidified body having a uniform layer thickness cannot be formed, and it becomes difficult to reduce drying unevenness. Therefore, when the temperature of the substrate W and the atmospheric temperature in the chamber 11 are equal to or lower than the melting point of the drying auxiliary substance, it is preferable to adjust the temperature so that the temperature of the drying auxiliary liquid is sufficiently higher than the melting point.

  The drying auxiliary liquid supplied to the surface Wf of the substrate W flows from the vicinity of the center of the surface Wf of the substrate W toward the peripheral portion of the substrate W due to the centrifugal force generated by the rotation of the substrate W, and the surface Wf of the substrate W Diffuses across the surface. As a result, the IPA adhering to the surface Wf of the substrate W is removed by supplying the drying auxiliary liquid, and the entire surface Wf of the substrate W is covered with the drying auxiliary liquid. After completion of the treatment liquid supply step S13, the control unit 13 issues an operation command to the valve 26 and closes the valve 26. Further, the control unit 13 issues an operation command to the turning drive unit 14 to position the nozzle 22 at the retracted position Pl.

  FIG. 8C shows the state of the substrate W at the end of the processing liquid supply step S13. As shown in FIG. 8C, the drying auxiliary liquid (indicated by “62” in the drawing) supplied in the processing liquid supply step S13 is applied to the surface Wf of the substrate W on which the pattern Wp is formed. The IPA 61 is attached and is replaced by the drying auxiliary liquid 62 and removed from the surface Wf of the substrate W.

  Returning to FIG. Next, a solidification step S14 is performed in which the drying auxiliary liquid 62 supplied to the surface Wf of the substrate W is solidified to form a solidified film of the drying auxiliary substance. First, the control unit 13 issues an operation command to the rotation driving unit 52 to rotate the substrate W around the axis A1 at a constant speed. At this time, the rotation speed of the substrate W is set to a speed at which the drying auxiliary liquid 62 can form a film having a predetermined thickness higher than the convex portion Wpl on the entire surface Wf.

  Subsequently, the control unit 13 issues an operation command to the valve 84 to open the valve 84. Thereby, the refrigerant (in this embodiment, 7 ° C. cold water) is supplied from the refrigerant reservoir 82 toward the back surface Wb of the substrate W through the pipe 83 and the refrigerant supply pipe 85.

  The cold water supplied toward the back surface Wb of the substrate W flows from the vicinity of the center of the back surface Wb of the substrate W toward the peripheral edge of the substrate W due to the centrifugal force generated by the rotation of the substrate W. It diffuses over the entire surface of Wb. Thereby, the liquid film of the drying auxiliary liquid 62 formed on the surface Wf of the substrate W is cooled to a low temperature below the freezing point of the drying auxiliary substance and solidified to form a solidified body.

  FIG. 8D shows the state of the substrate W at the end of the solidification step S14. As shown in FIG. 8D, the drying auxiliary liquid 62 supplied in the processing liquid supply step S13 is 7 ° C. cold water (shown as “64” in the drawing) on the back surface Wb of the substrate W. It is cooled by supply and solidifies to form a solidified body (indicated by “63” in the figure) containing a drying auxiliary substance.

  Returning to FIG. Next, a sublimation step S15 is performed in which the solidified body 63 formed on the surface Wf of the substrate W is sublimated and removed from the surface Wf of the substrate W. In the sublimation step S15, the coolant supply unit 81 continues the supply of cold water to the back surface Wb of the substrate W. Thereby, the solidified body 63 can be cooled at a temperature below the freezing point of the drying auxiliary substance, and the drying auxiliary substance can be prevented from melting from the back surface Wb side of the substrate W.

  In the sublimation step S15, first, the control unit 13 issues an operation command to the rotation drive unit 52 to rotate the substrate W around the axis A1 at a constant speed. At this time, the rotation speed of the substrate W is set to a speed at which the drying auxiliary liquid 62 can form a film having a predetermined thickness higher than the convex portion Wpl on the entire surface Wf.

  Subsequently, the control unit 13 issues an operation command to the turning drive unit 14 to position the nozzle 42 at the center of the surface Wf of the substrate W. Then, the control unit 13 issues an operation command to the valve 46 and opens the valve 46. Thereby, gas (7 ° C. nitrogen gas in the present embodiment) is supplied from the gas tank 47 toward the surface Wf of the substrate W through the pipe 45 and the nozzle 42.

  Here, the partial pressure of the vapor of the dry auxiliary substance in the nitrogen gas is set lower than the saturated vapor pressure of the dry auxiliary substance at the supply temperature of the nitrogen gas. Therefore, when such nitrogen gas is supplied to the surface Wf of the substrate W and comes into contact with the solidified body 63, the drying auxiliary substance is sublimated from the solidified body 63 into the nitrogen gas. Further, since the nitrogen gas has a temperature lower than the melting point of the drying auxiliary substance, the solidified body 63 can be sublimated while preventing the solidified body 63 from melting.

  As a result, the sublimation of the solid dry auxiliary substance prevents the surface tension from acting on the pattern Wp when the substance such as IPA existing on the surface Wf of the substrate W is removed, thereby suppressing the occurrence of pattern collapse. However, the surface Wf of the substrate W can be satisfactorily dried.

  FIG. 8E shows the state of the substrate W at the end of the sublimation step S15. As shown in FIG. 8 (e), the solidified body 63 of the drying auxiliary substance formed in the solidification step S14 is sublimated by the supply of nitrogen gas at 7 ° C. and removed from the surface Wf, and the surface Wf of the substrate W is obtained. Drying is completed.

  After completion of the sublimation step S15, the control unit 13 issues an operation command to the valve 46 and closes the valve 46. Further, the control unit 13 issues an operation command to the turning drive unit 14 to position the nozzle 42 at the retracted position P3.

  Thus, a series of substrate drying processes are completed. After the substrate drying process as described above, the substrate W after the drying process is carried out of the chamber 11 by a substrate carry-in / out mechanism (not shown).

  As described above, in this embodiment, the drying auxiliary liquid containing the dried auxiliary substance in the melted state is supplied to the surface Wf of the substrate W to which the IPA is adhered, and the drying auxiliary liquid is solidified on the surface Wf of the substrate W. After the solidified body containing the drying auxiliary substance is formed, the solidified body is sublimated and removed from the surface Wf of the substrate W, whereby the substrate W is dried.

  Here, in the solidified body, a dry auxiliary substance having a vapor pressure in the range of 20 ° C. to 25 ° C. of 5 kPa or more and a surface tension in the range of 20 ° C. to 25 ° C. of 25 mN / m or less is used. When the drying auxiliary substance sublimates, it is possible to reduce the non-uniform progression of the sublimation. As a result, stress can be prevented from being applied to the pattern, and pattern collapse on the substrate can be more reliably suppressed as compared with conventional substrate drying.

(Second Embodiment)
A second embodiment according to the present invention will be described below. This embodiment differs from the first embodiment in that nitrogen gas is supplied by the gas supply means 41 instead of the cold water supply by the refrigerant supply means 81 in the coagulation step S14. Even with such a configuration, the surface of the substrate can be satisfactorily dried while suppressing the collapse of the pattern.

<2-1 Overall Configuration of Substrate Processing Apparatus and Drying Auxiliary Solution>
Since the substrate processing apparatus and the control unit according to the second embodiment have basically the same configuration as the substrate processing apparatus 1 and the control unit 13 according to the first embodiment (see FIGS. 1 and 2), The description will be omitted with the same reference numerals. Moreover, since the drying auxiliary liquid used in this embodiment is the same as the drying auxiliary liquid according to the first embodiment, the description thereof is omitted.

<2-2 Substrate processing method>
Next, a substrate processing method according to the second embodiment using the substrate processing apparatus 1 having the same configuration as that of the first embodiment will be described.

  Hereinafter, the substrate processing steps will be described with reference to FIGS. 1, 2, 7 and 9 as appropriate. FIG. 9 is a schematic diagram showing the state of the substrate W in each step of FIG. In the second embodiment, each of the cleaning process S11, the IPA rinsing process S12, and the drying auxiliary liquid supply process S13 shown in FIG. 6 and FIGS. 9A to 9C is the first process. Since it is the same as that of embodiment, description is abbreviate | omitted.

  Here, FIG. 9A shows a state of the substrate W having the surface Wf covered with the liquid film of DIW 60 at the end of the cleaning step S11 in the second embodiment, and FIG. FIG. 9C shows the state of the substrate W having the surface Wf covered with the liquid film of the IPA 61 at the end of the IPA rinsing step S12 in the second embodiment. The state of the substrate W having the surface Wf covered with the liquid film of the drying auxiliary liquid 62 obtained by melting the drying auxiliary substance at the end of the drying auxiliary liquid supply step S13 is shown.

9A to 9E are processed under an atmospheric pressure environment unless otherwise specified. Here, the atmospheric pressure environment refers to an environment of 0.7 atmospheric pressure or higher and 1.3 atmospheric pressure or lower with a standard atmospheric pressure (1 atmospheric pressure, 1013 hPa) as a center. In particular, when the substrate processing apparatus 1 is disposed in a clean room that is at a positive pressure, the environment of the surface Wf of the substrate W is higher than 1 atmosphere. 9D and 9E (details will be described later) are performed under a reduced pressure environment of 17 Pa (17 × 10 ⁻⁵ atm).

  Please refer to FIG. After the cleaning step S11, the IPA rinsing step S12, and the drying auxiliary liquid supply step S13 are performed, the liquid film of the drying auxiliary liquid 62 supplied to the surface Wf of the substrate W is solidified to obtain a solidified body containing a drying auxiliary substance. A solidification step S14 to be formed is performed. Specifically, first, the control unit 13 issues an operation command to the rotation drive unit 52 to rotate the substrate W around the axis A1 at a constant speed. At this time, it is preferable that the rotation speed of the substrate W is set so that the film thickness of the liquid film made of the drying auxiliary liquid is higher than the height of the convex portion Wp1 on the entire surface Wf.

  Subsequently, the control unit 13 issues an operation command to the turning drive unit 14 to position the nozzle 42 at the center of the surface Wf of the substrate W. Then, the control unit 13 issues an operation command to the valve 46 and opens the valve 46. Thereby, gas (7 ° C. nitrogen gas in the present embodiment) is supplied from the gas tank 47 toward the surface Wf of the substrate W through the pipe 45 and the nozzle 42.

  The nitrogen gas supplied toward the surface Wf of the substrate W flows from the vicinity of the center of the surface Wf of the substrate W toward the periphery of the substrate W due to the centrifugal force generated by the rotation of the substrate W, and the drying auxiliary liquid It diffuses over the entire surface Wf of the substrate W covered with 62. Thereby, the liquid film of the drying auxiliary liquid 62 formed on the surface Wf of the substrate W is cooled to a low temperature below the freezing point of the drying auxiliary substance and solidified to form a solidified body.

  FIG. 9D shows the state of the substrate W at the end of the solidification step S14. As shown in FIG. 9D, the drying auxiliary liquid 62 supplied in the processing liquid supply step S13 is cooled and solidified by supplying nitrogen gas at 7 ° C., and a solidified body 63 containing a drying auxiliary substance is obtained. It is formed.

  Returning to FIG. Next, a sublimation step S15 is performed in which the solidified body 63 formed on the surface Wf of the substrate W is sublimated and removed from the surface Wf of the substrate W. Even in the sublimation step S15, the supply of gas (nitrogen gas) from the nozzle 42 is continued from the coagulation step S14.

  Here, the partial pressure of the vapor of the dry auxiliary substance in the nitrogen gas is set lower than the saturated vapor pressure of the dry auxiliary substance at the supply temperature of the nitrogen gas. Therefore, when such nitrogen gas is supplied to the surface Wf of the substrate W and comes into contact with the solidified body 63, the drying auxiliary substance is sublimated from the solidified body 63 into the nitrogen gas. Further, since the nitrogen gas has a temperature lower than the melting point of the drying auxiliary substance, the solidified body 63 can be sublimated while preventing the solidified body 63 from melting.

  As a result, the sublimation of the solid dry auxiliary substance prevents the surface tension from acting on the pattern Wp when the substance such as IPA existing on the surface Wf of the substrate W is removed, thereby suppressing the occurrence of pattern collapse. However, the surface Wf of the substrate W can be satisfactorily dried.

  FIG. 9E shows the state of the substrate W at the end of the sublimation step S15. As shown in FIG. 9 (e), the dried auxiliary substance solidified body 63 formed in the solidifying step S14 is sublimated by the supply of nitrogen gas at 7 ° C. and removed from the surface Wf, and the surface Wf of the substrate W is removed. Drying is completed.

  After completion of the sublimation step S15, the control unit 13 issues an operation command to the valve 46 and closes the valve 46. Further, the control unit 13 issues an operation command to the turning drive unit 14 to position the nozzle 42 at the retracted position P3.

  Thus, a series of substrate drying processes are completed. After the substrate drying process as described above, the substrate W after the drying process is carried out of the chamber 11 by a substrate carry-in / out mechanism (not shown).

  In the present embodiment, in the coagulation step S14 and the sublimation step S15, the common gas supply means 41 is used to convert nitrogen gas, which is inert to the dry auxiliary substance, to a temperature below the freezing point of the dry auxiliary substance. Supply with. Thereby, the sublimation step S15 can be started immediately after the solidification step S14, the processing time associated with operating each part of the substrate processing apparatus 1, and the memory amount of the substrate processing program 19 of the control unit 13 to be operated. In addition, since the number of parts used for processing can be reduced, there is an effect that the cost of the apparatus can be reduced. In particular, since the decompression means 71 is not used in this embodiment, the decompression means 71 can be omitted.

(Third embodiment)
A third embodiment according to the present invention will be described below. This embodiment is different from the second embodiment in that the inside of the chamber is decompressed in place of the supply of nitrogen gas in the coagulation step S14 and the sublimation step S15. Even with such a configuration, the surface of the substrate W can be satisfactorily dried while suppressing the collapse of the pattern.

<3-1 Overall Configuration of Substrate Processing Apparatus and Drying Aid>
Since the substrate processing apparatus and the control unit according to the third embodiment have basically the same configuration as the substrate processing apparatus 1 and the control unit 13 according to the first embodiment (see FIGS. 1 and 2), The description will be omitted with the same reference numerals. Moreover, since the drying auxiliary liquid used in this embodiment is the same as the drying auxiliary liquid according to the first embodiment, the description thereof is omitted.

<3-2 Substrate processing method>
Next, a substrate processing method according to the third embodiment using the substrate processing apparatus 1 having the same configuration as that of the first embodiment will be described.

  The substrate processing steps will be described below with reference to FIGS. 1, 2, 7 and 10 as appropriate. FIG. 10 is a schematic diagram showing the state of the substrate W in each step of FIG. In the third embodiment, the cleaning process S11, the IPA rinsing process S12, and the processing liquid supply process S13 shown in FIG. 7 and FIGS. 10 (a) to 10 (c) are performed in the first embodiment. Since it is the same as that of a form, description is abbreviate | omitted.

  Here, FIG. 10A shows a state of the substrate W having the surface Wf covered with the liquid film of DIW 60 at the end of the cleaning step S11 in the third embodiment, and FIG. FIG. 10C shows the state of the substrate W with the surface Wf covered with the liquid film of the IPA 61 at the end of the IPA rinsing step S12 in the third embodiment. The state of the substrate W having the surface Wf covered with the liquid film of the drying auxiliary liquid 62 obtained by melting the drying auxiliary substance (sublimation substance) at the end of the treatment liquid supply step S13 is shown.

Moreover, each figure to Fig.10 (a)-10 (e) is processed in an atmospheric pressure environment, unless otherwise indicated. Here, the atmospheric pressure environment refers to an environment of 0.7 atmospheric pressure or higher and 1.3 atmospheric pressure or lower with a standard atmospheric pressure (1 atmospheric pressure, 1013 hPa) as a center. In particular, when the substrate processing apparatus 1 is disposed in a clean room that is at a positive pressure, the environment of the surface Wf of the substrate W is higher than 1 atmosphere. 10D and 10E (details will be described later) are performed under a reduced pressure environment of 1.7 Pa (1.7 × 10 ⁻⁵ atm).

  Please refer to FIG. After the cleaning step S11, the IPA rinsing step S12, and the processing liquid supply step S13 are performed, the liquid film of the drying auxiliary liquid 62 supplied to the surface Wf of the substrate W is solidified to form a solidified body containing a drying auxiliary substance. The solidifying step S14 is performed. Specifically, first, the control unit 13 issues an operation command to the rotation drive unit 52 to rotate the substrate W around the axis A1 at a constant speed. At this time, it is preferable that the rotation speed of the substrate W is set so that the film thickness of the liquid film made of the drying auxiliary liquid is higher than the height of the convex portion Wp1 on the entire surface Wf.

  Subsequently, the control unit 13 issues an operation command to the exhaust pump 72 and starts driving the exhaust pump 72. Then, the control unit 13 issues an operation command to the valve 74 and opens the valve 74. Thereby, the gas inside the chamber 11 is exhausted to the outside of the chamber 11 through the pipe 73. By making the inside of the chamber 11 sealed except for the piping 73, the internal environment of the chamber 11 is reduced from atmospheric pressure.

The pressure is reduced from atmospheric pressure (about 1 atm, about 1013 hPa) to about 1.7 × 10 ⁻⁵ atm (1.7 Pa). In the implementation of the present invention, the pressure is not limited to the pressure, and the pressure in the chamber 11 after the pressure reduction may be set as appropriate according to the pressure resistance of the chamber 11 and the like. When the inside of the chamber 11 is depressurized, the drying auxiliary liquid 62 supplied to the surface Wf of the substrate W is evaporated, and the drying auxiliary liquid 62 is cooled and solidified by the heat of vaporization.

  FIG. 10D shows the state of the substrate W at the end of the solidification step S14. As shown in FIG. 10D, the drying auxiliary liquid 62 supplied in the processing liquid supply step S13 is cooled and solidified by evaporation of the drying auxiliary liquid 62 caused by the reduced pressure in the chamber 11, and drying assistance is performed. A solidified body 63 of material is formed.

  At this time, the layer thickness of the solidified body 63 is reduced by the amount of the dry auxiliary liquid 62 evaporated. For this reason, in the treatment liquid supply step S13 in this embodiment, the drying auxiliary liquid 62 becomes a liquid film having a predetermined thickness or more in consideration of the evaporation of the drying auxiliary liquid 62 in the coagulation step S14. In addition, it is preferable to adjust the rotation speed of the substrate W or the like.

  Returning to FIG. Next, a sublimation step S15 is performed in which the solidified body 63 formed on the surface Wf of the substrate W is sublimated and removed from the surface Wf of the substrate W. Also in the sublimation step S15, the decompression process in the chamber 11 by the decompression means 71 is continued from the coagulation step S14.

  By the decompression process, the environment in the chamber 11 becomes a pressure lower than the saturation vapor pressure of the drying auxiliary substance. Therefore, when such a reduced pressure environment is maintained, the drying auxiliary substance is sublimated from the solidified body 63.

  Even when sublimation of the drying auxiliary substance occurs from the solidified body 63, the solidified body 63 is cooled because heat is taken from the solidified body 63 as sublimation heat. Therefore, in the third embodiment, the sublimation step S15 separately cools the solidified body 63 even when the environment in the chamber 11 is slightly higher than the melting point of the drying auxiliary substance (room temperature environment). The solidified body 63 can be maintained at a temperature lower than the melting point of the drying auxiliary substance, and the solidified body 63 can be sublimated while preventing the solidified body 63 from melting. As a result, it is not necessary to provide a separate cooling mechanism, and the apparatus cost and processing cost can be reduced.

  As described above, the sublimation of the solid dry auxiliary substance prevents the surface tension from acting on the pattern Wp when removing the substance such as IPA existing on the surface Wf of the substrate W, thereby preventing the pattern collapse. The surface Wf of the substrate W can be satisfactorily dried while being suppressed.

  FIG. 10E shows the state of the substrate W at the end of the sublimation step S15. As shown in FIG. 10E, the solidified body 63 of the drying auxiliary material formed in the solidification step S14 is sublimated and removed from the surface Wf by setting the inside of the chamber 11 to a reduced pressure environment, and the substrate W Drying of the surface Wf is completed.

  After completion of the sublimation step S15, the control unit 13 issues an operation command to the valve 74 and opens the valve 74. Further, the control unit 13 issues an operation command to the exhaust pump 72 and stops the operation of the exhaust pump 72. The control unit 13 issues an operation command to the valve 46 and opens the valve 46 to introduce gas (nitrogen gas) from the gas tank 47 into the chamber 11 through the pipe 45 and the nozzle 42. The inside is returned from the reduced pressure environment to the atmospheric pressure environment. At this time, the nozzle 42 may be positioned at the retracted position P3 or may be positioned at the center of the surface Wf of the substrate W.

  Note that the method for returning the interior of the chamber 11 to the atmospheric pressure environment after the sublimation step S15 is not limited to the above, and various known methods may be employed.

  Thus, a series of substrate drying processes are completed. After the substrate drying process as described above, the substrate W after the drying process is carried out of the chamber 11 by a substrate carry-in / out mechanism (not shown).

  As described above, in this embodiment, the drying auxiliary liquid obtained by melting the drying auxiliary substance is supplied to the surface Wf of the substrate W to which the IPA is attached to replace it. Thereafter, the drying auxiliary liquid is solidified on the surface Wf of the substrate W to form a solidified film of the drying auxiliary substance, and then the drying auxiliary substance is sublimated and removed from the surface Wf of the substrate W. Thereby, the drying process of the board | substrate W is performed.

  Even if the drying auxiliary liquid is solidified and sublimated by reducing the pressure as in this embodiment, the substrate W can be satisfactorily dried while preventing the pattern from collapsing. A specific pattern suppressing effect will be described in an example described later.

  Further, in the present embodiment, the inside of the chamber 11 is decompressed using the common decompression means 71 in the coagulation step S14 and the sublimation step S15. Thereby, the sublimation step S15 can be started immediately after the solidification step S14, the processing time associated with operating each part of the substrate processing apparatus 1, and the memory amount of the substrate processing program 19 of the control unit 13 to be operated. In addition, since the number of parts used for processing can be reduced, there is an effect that the cost of the apparatus can be reduced. In particular, since the low temperature nitrogen gas is not used in the third embodiment, the temperature adjustment unit 272 in the gas supply means 41 may be omitted, and when the chamber 11 is returned from the reduced pressure environment to the atmospheric pressure environment, When means other than the gas supply means 41 are used, the gas supply means 41 may be omitted.

(Modification)
In the above description, preferred embodiments of the present invention have been described. However, the present invention is not limited to these embodiments, and can be implemented in various other forms. Below, other main forms are illustrated.

  In the first embodiment and the second embodiment, each process is performed on the substrate W in one chamber 11. However, the implementation of the present invention is not limited to this, and a chamber may be prepared for each process.

  For example, in each embodiment, after the solidification step S14 is performed in the first chamber and the solidified film is formed on the surface Wf of the substrate W, the substrate W is unloaded from the first chamber, and the solidified film is transferred to another second chamber. The substrate W on which is formed may be carried in, and the sublimation step S15 may be performed in the second chamber.

  Further, in the first embodiment, in the sublimation step S <b> 15, the nitrogen gas is supplied by the gas supply unit 41 while the cold water supply by the refrigerant supply unit 81 is continued. However, the implementation of the present invention is not limited to this, and the supply of nitrogen gas by the gas supply means 41 is stopped, and the drying auxiliary substance in the solidified body 63 is naturally sublimated while supplying cold water by the refrigerant supply means 81. Good.

  Hereinafter, preferred embodiments of the present invention will be described in detail by way of example. However, the materials, blending amounts, and the like described in the examples are not intended to limit the scope of the present invention only to those unless otherwise specified.

(substrate)
As a substrate, a silicon substrate having a model pattern formed on the surface was prepared. FIG. 11 shows an SEM (Scanning Electron Microscope) image representing the surface on which the model pattern of the silicon substrate is formed. As the model pattern, a pattern in which cylinders having a diameter of 30 nm and a height of 480 nm (an aspect ratio of 16) were arranged with an interval of about 80 nm was adopted. In FIG. 11, the portion shown in white is the head of the cylindrical portion (that is, the convex portion of the pattern), and the portion shown in black is the concave portion of the pattern. As shown in FIG. 11, it has been confirmed that white circles having regularly the same size are regularly arranged on the pattern forming surface.

Example 1
In this example, the silicon substrate was dried by the procedure described below, and the effect of suppressing pattern collapse was evaluated. In the processing of the silicon substrate, the substrate processing apparatus described in the first embodiment was used.

<Procedure 1-1 UV Irradiation>
First, the surface of the silicon substrate was irradiated with ultraviolet light to make its surface characteristics hydrophilic. This facilitated the entry of the liquid into the concave portion of the pattern, and artificially created an environment in which the pattern was likely to collapse after the liquid was supplied.

<Procedure 1-2 Supply process>
Next, in the chamber 11 under atmospheric pressure, a drying auxiliary liquid (liquid temperature 40 ° C.) obtained by melting the sublimation substance was directly supplied to the pattern forming surface of the dried silicon substrate. As a result, a liquid film made of the drying auxiliary liquid was formed on the pattern forming surface of the silicon substrate. As the sublimable substance, 1,1,2,2,3,3,4-heptafluorocyclopentane represented by the following chemical structural formula was used. The compound has a surface tension of 19.6 mN / m in an environment of 25 ° C. and a vapor pressure of 8.2 kPa (62.0 mmHg) in an environment of 20 ° C. (both are literature values, see Table 1 below) ). The melting point and freezing point are 20.5 ° C., and the specific gravity is 1.58 in an environment of 25 ° C. Furthermore, since the compound is excellent in solubility of, for example, a fluorine-based polymer, it is used as a solvent for various coating agents and as a cleaning agent for oil film stains.

<Procedure 1-3 Solidification process>
Subsequently, under an atmospheric pressure environment, nitrogen gas at 7 ° C. was supplied onto the liquid film made of the drying auxiliary liquid, and the drying auxiliary liquid was solidified to form a solidified body.

<Procedure 1-4 Sublimation process>
Furthermore, in a normal temperature and atmospheric pressure environment, nitrogen gas at 7 ° C. is continuously supplied to the solidified body, thereby sublimating the drying auxiliary substance (sublimable substance) while preventing the solidified body from melting, The solidified body was removed from the pattern forming surface of the silicon substrate. The temperature of nitrogen gas is 7 ° C., which is lower than the melting point (20.5 ° C.) of 1,1,2,2,3,3,4-heptafluorocyclopentane. Separate cooling was not performed.

FIG. 12 is an SEM image of the silicon substrate after the procedure 1-1 to the procedure 1-4 are executed. Compared to the pattern formation surface of the silicon substrate before the drying process (see FIG. 11), pattern collapse was reduced, and the collapse rate in the displayed region was 15.7%. As a result, when 1,1,2,2,3,3,4-heptafluorocyclopentane is used as a drying auxiliary substance, the collapse of the pattern can be suppressed extremely well, which is effective for sublimation drying. It was shown that there is.
The collapse rate is a value calculated by the following equation.
Collapse rate (%) = (Number of collapsed protrusions in an arbitrary area) ÷ (Total number of protrusions in the area) × 100

(Example 2)
In this example, instead of 1,1,2,2,3,3,4-heptafluorocyclopentane as a dry auxiliary substance, dodecafluorocyclohexane (vapor pressure 33.1 kPa (25 ° C.), surface tension 12.6 mN / m (25 ° C.), melting point and freezing point 51 ° C., both of which are literature values) were used (see Table 1 below). Other than that was carried out similarly to Example 1, the procedure 1-1 to the procedure 1-4 was performed, and the freeze-drying of the pattern formation surface of the silicon substrate was performed.

  FIG. 13 is an SEM image of the silicon substrate after steps 1-1 to 1-4 are executed in this embodiment. Compared to the pattern formation surface of the silicon substrate before the drying process (see FIG. 11), the pattern collapse was greatly reduced, and the collapse rate in the displayed area was 2.5%. Thereby, when dodecafluorocyclohexane was used as a drying auxiliary substance, it was shown that the collapse of the pattern can be suppressed very well and is effective for sublimation drying.

(Comparative Example 1)
In this comparative example, instead of 1,1,2,2,3,3,4-heptafluorocyclopentane as a dry auxiliary substance, t-butanol (vapor pressure 4.1 kPa (20 ° C.), surface tension) 19.56 mN / m (20 ° C.), melting point and freezing point 25 ° C., both of which are literature values) were used (see Table 1 below). Other than that was carried out similarly to Example 1, the procedure 1-1 to the procedure 1-4 was performed, and the freeze-drying of the pattern formation surface of the silicon substrate was performed.

  FIG. 14 is an SEM image of the silicon substrate after steps 1-1 to 1-4 are executed in this embodiment. Compared to the pattern formation surface of the silicon substrate before the drying process (see FIG. 11), the pattern collapse was not reduced, and the collapse rate in the displayed region was 52.3%. Thereby, when t-butanol was used as a drying auxiliary substance, it was confirmed that reduction of pattern collapse was insufficient.

(Comparative Example 2)
In this comparative example, instead of 1,1,2,2,3,3,4-heptafluorocyclopentane, acetic acid (vapor pressure 1.50 kPa (20 ° C.), surface tension 27. 7 mN / m (20 ° C.), melting point and freezing point 17 ° C., both of which are literature values) (see Table 1 below). Other than that was carried out similarly to Example 1, the procedure 1-1 to the procedure 1-4 was performed, and the freeze-drying of the pattern formation surface of the silicon substrate was performed.

  FIG. 15 is an SEM image of the silicon substrate after steps 1-1 to 1-4 are executed in this embodiment. Compared to the pattern formation surface of the silicon substrate before the drying process (see FIG. 11), the pattern collapsed significantly, and the collapse rate in the displayed region was 99.1%. Thereby, when t-butanol was used as a drying auxiliary substance, it was confirmed that reduction of pattern collapse was insufficient.

(Comparative Example 3)
In this comparative example, instead of 1,1,2,2,3,3,4-heptafluorocyclopentane, 1,4-dioxane (vapor pressure 3.9 kPa (20 ° C.), A surface tension of 33.4 mN / m (25 ° C.), a melting point and a freezing point of 11 ° C., both of which are literature values) were used (see Table 1 below). Other than that was carried out similarly to Example 1, the procedure 1-1 to the procedure 1-4 was performed, and the freeze-drying of the pattern formation surface of the silicon substrate was performed.

  FIG. 16 is an SEM image of the silicon substrate after steps 1-1 to 1-4 are executed in this embodiment. Compared to the pattern formation surface of the silicon substrate before the drying process (see FIG. 11), the pattern collapsed significantly, and the collapse rate in the displayed region was 99.3%. Thereby, when t-butanol was used as a drying auxiliary substance, it was confirmed that reduction of pattern collapse was insufficient.

(Comparative Example 4)
In this comparative example, instead of 1,1,2,2,3,3,4-heptafluorocyclopentane as a dry auxiliary substance, 4,4-difluorocyclohexane (vapor pressure 0.37 kPa (25 ° C.) The surface tension was 29.2 mN / m (25 ° C.), the melting point and the freezing point were 35 to 36 ° C. (both are literature values) (see Table 1 below). Other than that was carried out similarly to Example 1, the procedure 1-1 to the procedure 1-4 was performed, and the freeze-drying of the pattern formation surface of the silicon substrate was performed.

  FIG. 17 is an SEM image of the silicon substrate after steps 1-1 to 1-4 are executed in this embodiment. Compared with the pattern formation surface of the silicon substrate before the drying process (see FIG. 11), the pattern collapsed significantly, and the collapse rate in the displayed region was 97.0%. Thereby, when t-butanol was used as a drying auxiliary substance, it was confirmed that reduction of pattern collapse was insufficient.

(Comparative Example 5)
In this comparative example, instead of 1,1,2,2,3,3,4-heptafluorocyclopentane as a dry auxiliary substance, fluorocyclohexane (vapor pressure 5.67 kPa (25 ° C.), surface tension 21 0.8 mN / m (25 ° C.), melting point and freezing point 13 ° C., both of which are literature values) (see Table 1 below). Other than that was carried out similarly to Example 1, the procedure 1-1 to the procedure 1-4 was performed, and the freeze-drying of the pattern formation surface of the silicon substrate was performed.

  FIG. 18 is an SEM image of the silicon substrate after steps 1-1 to 1-4 are executed in this example. Compared to the pattern formation surface of the silicon substrate before the drying process (see FIG. 11), the pattern collapse was not reduced, and the collapse rate in the displayed region was 35.8%. Thereby, when t-butanol was used as a drying auxiliary substance, it was confirmed that reduction of pattern collapse was insufficient.

(result)
As shown in FIGS. 12 to 18, in the case of Examples 1 and 2 using 1,1,2,2,3,3,4-heptafluorocyclopentane and dodecafluorocyclohexane as a drying auxiliary substance, It was confirmed that the occurrence of pattern collapse can be reduced as compared with Comparative Examples 1 to 5 using a conventional dry auxiliary substance.

  The present invention can be applied to a drying technique for removing a liquid adhering to the surface of a substrate and a substrate processing technique for treating the surface of a substrate using the drying technique.

DESCRIPTION OF SYMBOLS 1, 10 Substrate processing apparatus 11 Chamber 12 Spattering prevention cup 13 Control unit 14 Rotation drive part 15 Arithmetic processing part 17 Memory 19 Substrate processing program 21 Processing liquid supply means (supply means)
22 Nozzle 23 Arm 24 Rotating shaft 25 Pipe 26 Valve 27 Treatment liquid storage unit 31 IPA supply means 32 Nozzle 33 Arm 34 Rotating shaft 35 Pipe 36 Valve 37 IPA tank 41 Gas supply means (coagulation means, sublimation means)
42 Nozzle 43 Arm 44 Rotating shaft 45 Pipe 46 Valve 47 Gas tank 51 Substrate holding means 52 Rotation drive unit 53 Spin base 54 Chuck pin 61 IPA
62 Drying auxiliary liquid 63 Solidified body 64 Cold water 71 Depressurizing means (coagulating means, sublimation means)
72 Exhaust pump 74 Valve 81 Refrigerant supply means (coagulation means, sublimation means)
82 Refrigerant storage part 83 Pipe 84 Valve 271 Processing liquid storage tank 272 Temperature adjustment part 273 Pipe 274 Pressurization part 275 Nitrogen gas tank 276 Pump 277 Stirring part 278 Stirring control part 279 Rotating part 471 Gas storage part 472 Gas temperature adjusting part 821 Refrigerant tank 822 Refrigerant temperature adjustment unit A1, J1, J2, J3, J4 Axes AR1, AR2, AR3, AR4 Arrows P1, P2, P3, P4 Retraction position S11 Cleaning step S12 IPA rinsing step S13 Treatment liquid supply step (supply step)
S14 Solidification step S15 Sublimation step S16 Cleaning / rinsing step S17 Water repellent treatment step W Substrate Wf (Substrate) Front surface Wb (Substrate) Back surface Wp (Substrate surface) Pattern Wp1 (Pattern) Convex portion Wp2 (Pattern) Concave portion

Claims (15)

Supply means for supplying a treatment liquid containing a sublimable substance in a molten state to the pattern forming surface of the substrate;
Solidifying means for solidifying the treatment liquid on the pattern forming surface to form a solidified body;
Sublimation means for sublimating the solidified body and removing it from the pattern forming surface;
With
The substrate processing apparatus, wherein the sublimable substance has a vapor pressure of 5 kPa or more at 20 ° C. to 25 ° C. and a surface tension of 25 mN / m or less at 20 ° C. to 25 ° C. The substrate processing apparatus according to claim 1,
The substrate processing apparatus whose surface tension in 20 to 25 degreeC of the said sublimable substance is 20 mN / m or less. The substrate processing apparatus according to claim 1, wherein:
The substrate processing apparatus, wherein the sublimable substance is 1,1,2,2,3,3,4-heptafluorocyclopentane or dodecafluorocyclohexane. The substrate processing apparatus according to any one of claims 1 to 3,
The supply means supplies the processing liquid to the pattern forming surface of the substrate under atmospheric pressure,
The substrate processing apparatus, wherein the solidifying means cools the processing liquid below the freezing point of the sublimable substance under atmospheric pressure. A substrate processing apparatus according to any one of claims 1 to 4, wherein
The sublimable substance has sublimability under atmospheric pressure,
The substrate processing apparatus, wherein the sublimation means sublimates the sublimable substance under atmospheric pressure. The substrate processing apparatus according to claim 4 or 5, wherein
At least one of the solidification means and the sublimation means is a refrigerant supply means for supplying the refrigerant toward the back surface of the substrate opposite to the pattern formation surface at a temperature not higher than the freezing point of the sublimable substance. A substrate processing apparatus. The substrate processing apparatus according to claim 4 or 5, wherein
At least one of the solidification means and the sublimation means is a gas supply means for supplying a gas inert to at least the sublimable substance toward the pattern forming surface at a temperature below the freezing point of the sublimation substance. A substrate processing apparatus. The substrate processing apparatus according to claim 4 or 5, wherein
The sublimation means includes a gas supply means for supplying at least a gas inert to the sublimable substance toward the pattern forming surface at a temperature equal to or lower than a freezing point of the sublimable substance, and a refrigerant. A substrate processing apparatus, characterized in that the substrate processing apparatus is a coolant supply means for supplying the substrate toward a back surface opposite to the pattern forming surface at a temperature equal to or lower than a freezing point of the substance. A substrate processing apparatus according to any one of claims 1 to 4, wherein
The substrate processing apparatus, wherein the sublimation means is a decompression means for decompressing the pattern forming surface on which the solidified body is formed in an environment lower than atmospheric pressure. The substrate processing apparatus according to any one of claims 1 to 3,
The substrate processing apparatus, wherein the coagulating means is a pressure reducing means for reducing the pressure of the pattern forming surface supplied with the processing liquid in an environment lower than atmospheric pressure. The substrate processing apparatus according to claim 10, comprising:
A substrate processing apparatus using the decompression means as the sublimation means. The substrate processing apparatus according to any one of claims 1 to 11,
The substrate processing apparatus, wherein the supply means includes a processing liquid temperature adjusting unit that adjusts the temperature of the processing liquid to a temperature equal to or higher than the melting point of the sublimable substance and lower than the boiling point. A supply method of supplying a treatment liquid containing a sublimable substance in a molten state to the pattern forming surface of the substrate;
A solidification method in which the treatment liquid is solidified on the pattern forming surface to form a solidified body;
A sublimation method for sublimating the solidified body and removing it from the pattern forming surface;
Including
The substrate treatment method, wherein a vapor pressure of the sublimable substance at 20 ° C. to 25 ° C. is 5 kPa or more and a surface tension at 20 ° C. to 25 ° C. is 25 mN / m or less. The substrate processing method according to claim 13, comprising:
The substrate processing method whose surface tension in 20 to 25 degreeC of the said sublimable substance is 20 mN / m or less. The substrate processing apparatus according to claim 13 or 14,
A substrate processing method, wherein the sublimable substance is 1,1,2,2,3,3,4-heptafluorocyclopentane or dodecafluorocyclohexane.