阅读说明：本技术 基板处理方法以及基板处理装置 (Substrate processing method and substrate processing apparatus ) 是由 高桥弘明 白川元 于 2020-02-26 设计创作，主要内容包括：本发明的基板处理方法具有：在第一处理部中对在表面形成有凹凸图案的基板实施湿式处理(步骤S104)之后,以包括有机溶剂的液膜覆盖基板的表面,使该液膜的至少表面凝固而形成凝固膜的工序(步骤S105)；将由凝固膜覆盖的基板向第二处理部搬运的工序(步骤S106、S107)；在第二处理部中向凝固膜供给溶解液,来溶解凝固膜,从基板的表面去除溶解液而使基板干燥的工序(步骤S108)。既能够可靠地防止形成于基板的表面的凹凸图案的崩塌,又能够确保处理单元间的搬运的容易度。(The substrate processing method of the present invention includes: a step (S105) of performing wet processing on a substrate having a surface on which an uneven pattern is formed in a first processing unit (step S104), then covering the surface of the substrate with a liquid film containing an organic solvent, and solidifying at least the surface of the liquid film to form a solidified film; a step (S106, S107) of conveying the substrate covered with the solidified film to a second processing unit; and a step (S108) of supplying a dissolving liquid to the solidified film in the second processing unit to dissolve the solidified film, and removing the dissolving liquid from the surface of the substrate to dry the substrate. The processing units can be easily transported while reliably preventing the collapse of the uneven pattern formed on the surface of the substrate.)

1. A method for processing a substrate, wherein,

comprising:

a step of performing wet processing on a substrate having a concave-convex pattern formed on a surface thereof in a first processing unit, and then covering the surface of the substrate with a liquid film containing an organic solvent;

solidifying at least the surface of the liquid film to form a solidified film;

a step of conveying the substrate covered with the solidified film to a second processing unit;

supplying a dissolving liquid to the solidified film in the second processing section to dissolve the solidified film; and

and a step of removing the solution from the surface of the substrate to dry the substrate.

2. The substrate processing method according to claim 1, wherein,

the solidified film is formed by cooling at least a surface of the liquid film.

3. The substrate processing method according to claim 1 or 2, wherein,

in the step of drying the substrate, the substrate is dried using a supercritical fluid.

4. The substrate processing method according to any one of claims 1 to 3,

the second processing unit has a chamber for receiving the substrate;

in the chamber, the solution is replaced with a liquid low surface tension liquid, and then the low surface tension liquid is vaporized from a supercritical fluid state to dry the substrate.

5. The substrate processing method according to claim 3 or 4,

the supercritical fluid is carbon dioxide.

6. The substrate processing method according to any one of claims 1 to 5,

at least the surface of the liquid film is converted into the solidified film by cooling, and a part of the liquid film is maintained in a liquid state between the solidified film and the substrate.

7. The substrate processing method according to any one of claims 1 to 6,

the organic solvent contained in the liquid film is isopropanol or acetone.

8. The substrate processing method according to any one of claims 1 to 7,

the liquid film further includes an additive having a melting point equal to or higher than normal temperature, in addition to the organic solvent.

9. The substrate processing method according to claim 8, wherein,

the additive is tert-butanol.

10. The substrate processing method according to any one of claims 1 to 9,

the dissolving solution is isopropanol or acetone.

11. The substrate processing method according to any one of claims 1 to 10,

forming a filling liquid film filling the inside of the uneven pattern and a solidifying liquid film covering the filling liquid film with a material different from the filling liquid film as the liquid film;

the solidifying liquid film is solidified by cooling to a temperature lower than the solidifying point of the liquid constituting the solidifying liquid film.

12. The substrate processing method according to claim 11, wherein,

the freezing point of the liquid constituting the solidifying liquid film is lower than the freezing point of the liquid constituting the filling liquid film.

13. The substrate processing method according to claim 11, wherein,

the solidifying point of the liquid constituting the filling liquid film is not more than normal temperature, and the solidifying point of the liquid constituting the solidifying liquid film is not less than normal temperature.

14. A substrate processing apparatus, wherein,

comprising:

a first processing unit that performs wet processing on a substrate having a concave-convex pattern formed on a surface thereof, processing for covering the surface of the substrate with a liquid film, and processing for cooling to a temperature lower than a freezing point of a liquid constituting the liquid film to solidify the liquid film to convert the liquid film into a solidified film;

a second processing unit that receives the substrate on which the solidified film is formed, and performs a process of supplying a dissolving liquid to the solidified film to dissolve the solidified film, and a process of removing the dissolving liquid from the surface of the substrate to dry the substrate; and

and a conveying mechanism for conveying the substrate on which the solidified film is formed from the first processing unit to the second processing unit.

15. The substrate processing apparatus of claim 14,

the first processing unit includes:

a treatment liquid supply unit configured to supply a treatment liquid for the wet treatment to the substrate;

a solidification liquid supply unit configured to supply a solidification liquid for forming the liquid film to the substrate; and

a cooling gas supply unit configured to supply a cooling gas having a temperature lower than a freezing point of the solidification liquid to the substrate,

the second processing unit includes:

a solution supply unit configured to supply the solution to the substrate; and

and a fluid supply unit for supplying a fluid for replacing the dissolving solution.

16. The substrate processing apparatus of claim 15, wherein,

the second processing unit has a chamber for accommodating the substrate, and the fluid supply unit supplies the fluid in a supercritical state to an internal space of the chamber.

17. The substrate processing apparatus according to claim 15 or 16,

the fluid is carbon dioxide.

18. The substrate processing apparatus according to any one of claims 14 to 17, wherein

The dissolving solution is an organic solvent.

19. The substrate processing apparatus of claim 18,

the dissolving solution is isopropanol or acetone.

Technical Field

The present invention relates to a substrate processing method including a step of drying a substrate having a concave-convex pattern formed on a surface thereof after wet processing, and a substrate processing apparatus for performing the substrate processing method.

Background

In a substrate processing technique in which a substrate having a fine uneven pattern formed on a surface thereof is subjected to wet processing (for example, cleaning processing) with a liquid and then dried, it is known that there is a problem of pattern collapse due to the action of surface tension of the liquid remaining in the pattern during the drying processing. To solve this problem, there are the following prior art: the liquid is dried after being replaced with a fluid having a lower surface tension. As a fluid having an extremely low surface tension, there is a fluid using, for example, liquid carbon dioxide (see, for example, patent document 1).

Further, as another conventional technique, there is a sublimation drying technique. In this technique, a liquid film of a liquid sublimable substance is formed on the surface of a substrate after wet treatment, and then the substrate is cooled and solidified. Then, the solidified sublimable substance is sublimated, so that a gas-liquid interface which causes pattern collapse is not generated (for example, see patent document 2).

In the related art, a treatment unit for forming a liquid film on a surface of a substrate and a treatment unit for drying the substrate are separate bodies. Therefore, a transfer mechanism for transferring the substrate between the units is provided.

Documents of the prior art

Patent document 1: japanese patent laid-open publication No. 2013-201302

Patent document 2: japanese patent laid-open No. 2012-243869

Disclosure of Invention

Problems to be solved by the invention

In the conventional technique described in patent document 1, it is necessary to convey the substrate while maintaining the liquid film formed on the surface. Therefore, the substrate must be always kept in a horizontal posture, and the conveyance speed must be low. However, the liquid may flow out due to vibration during transportation or the substrate surface may be exposed due to evaporation, which may cause pattern collapse.

In contrast, in the conventional technique described in patent document 2, since the substrate is conveyed in a state where the surface of the substrate is covered with the solidified sublimable substance, the restriction during conveyance is less. However, the further miniaturization of the pattern may cause a problem that cannot be dealt with by this technique. The reason for this is as follows.

In general, the physical property value known as the freezing point of a liquid is a value when the liquid is in a free space or a large space. On the other hand, in a liquid that enters a fine space such as a nanometer level, the freezing point is greatly lowered than the above-mentioned general numerical value. Therefore, unless the cooling temperature is sufficiently lowered and the cooling time is not prolonged, the liquid penetrating into the fine pattern does not sufficiently solidify and remains in a liquid state. Thus, the sublimation drying process after conveyance is actually a process through a liquid phase rather than "sublimation", and a gas-liquid interface may occur, which may cause pattern collapse.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for reliably preventing pattern collapse while ensuring ease of conveyance between processing units in a substrate processing technique in which a substrate having an uneven pattern formed on a surface thereof is subjected to wet processing and then dried.

Means for solving the problems

In order to achieve the above object, one embodiment of a substrate processing method according to the present invention includes: a step of performing wet processing on a substrate having a concave-convex pattern formed on a surface thereof in a first processing unit, and then covering the surface of the substrate with a liquid film containing an organic solvent; solidifying at least the surface of the liquid film to form a solidified film; a step of conveying the substrate covered with the solidified film to a second processing unit; supplying a dissolving liquid to the solidified film in the second processing section to dissolve the solidified film; and a step of removing the solution from the surface of the substrate to dry the substrate.

In order to achieve the above object, one embodiment of the substrate processing apparatus according to the present invention includes: a first processing unit that performs wet processing on a substrate having a concave-convex pattern formed on a surface thereof, processing for covering the surface of the substrate with a liquid film, and processing for cooling to a temperature lower than a freezing point of a liquid constituting the liquid film to solidify the liquid film to convert the liquid film into a solidified film; a second processing unit that receives the substrate on which the solidified film is formed, and performs a process of supplying a dissolving liquid to the solidified film to dissolve the solidified film, and a process of removing the dissolving liquid from the surface of the substrate to dry the substrate; and a conveying mechanism for conveying the substrate on which the solidified film is formed from the first processing unit to the second processing unit.

In the invention thus constituted, the transfer of the substrate from the first processing unit to the second processing unit is performed in a state where the surface of the substrate is covered with the solidified film. Therefore, the possibility of exposure of the substrate surface due to liquid loss or evaporation from the substrate surface during conveyance is very low. Therefore, the substrate can be transported easily.

Then, in the second processing unit for conveying the substrate, the solidified film is dissolved in a dissolving solution, and then the dissolving solution is removed to dry the substrate. Therefore, unlike the sublimation drying technique in which the solidified film is directly sublimated, the liquid that has entered the inside of the pattern is not solidified, and therefore does not cause the pattern collapse. That is, according to the present invention, even a fine pattern can be prevented from collapsing.

In consideration of the ease of replacement with another fluid in the subsequent step, a mode in which the liquid inside the pattern is not solidified is preferable. For the convenience of handling, it is sufficient to solidify the surface portion of the liquid film. Thus, the energy and time required for cooling the liquid film can also be small. That is, the present invention can be said to have excellent operational effects also from the viewpoint of energy efficiency and processing ability.

ADVANTAGEOUS EFFECTS OF INVENTION

As described above, in the present invention, in the substrate processing technique in which the substrate having the uneven pattern formed on the surface thereof is subjected to the wet processing and then dried, the substrate can be easily transported and the collapse of the substrate can be reliably prevented even in a fine pattern.

The above and other objects and novel features of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings. The drawings, however, are intended to be illustrative only and not limiting as to the scope of the invention.

Drawings

Fig. 1A is a diagram showing a schematic configuration of one embodiment of a substrate processing apparatus according to the present invention.

Fig. 1B is a diagram schematically showing a configuration of one embodiment of a substrate processing apparatus according to the present invention.

Fig. 2 is a diagram showing the structure and installation environment of the center robot.

Fig. 3A is a diagram illustrating a substrate processing unit performing wet processing.

Fig. 3B is a diagram illustrating a substrate processing unit performing wet processing.

Fig. 3C is a diagram illustrating a substrate processing unit performing wet processing.

Fig. 4 is a diagram showing a substrate processing unit that executes a supercritical drying process.

Fig. 5 is a flowchart showing the operation of the substrate processing apparatus.

Fig. 6 is a flowchart showing the coagulation process.

Fig. 7 is a flowchart showing the drying process.

Fig. 8A is a diagram schematically illustrating a problem that may occur in the solidified film.

Fig. 8B is a diagram schematically showing a problem that may occur in the solidified film.

Fig. 8C is a diagram schematically showing a problem that may occur in the solidified film.

Fig. 9 is a flowchart showing another example of the solidification processing.

Fig. 10 is a view schematically showing the state of the liquid film of this modification.

Detailed Description

Fig. 1A and 1B are diagrams illustrating a schematic configuration of one embodiment of a substrate processing apparatus according to the present invention. More specifically, fig. 1A is a plan view showing a substrate processing apparatus 1 according to an embodiment of the present invention, and fig. 1B is a side view showing the substrate processing apparatus 1. Further, these drawings do not show the external appearance of the device, but show a schematic view for facilitating understanding of the internal structure of the device by excluding an outer wall panel or other partial structure of the device. The substrate processing apparatus 1 is an apparatus that is installed in, for example, a clean room and performs a predetermined process on a substrate.

Here, as the "substrate" in the present embodiment, various substrates such as a semiconductor substrate, a glass substrate for a photomask, a glass substrate for a liquid crystal Display, a glass substrate for a plasma Display, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, and a substrate for an optical disk can be applied. Hereinafter, a substrate processing apparatus mainly used for processing a semiconductor substrate will be described as an example with reference to the drawings. However, the present invention can be similarly applied to the above-exemplified processing of various substrates.

As shown in fig. 1A, the substrate processing apparatus 1 includes a substrate processing unit 10 that processes a substrate S, and an indexer unit 20 coupled to the substrate processing unit 10. The indexer block 20 includes a container holding block 21 and an indexer robot 22. The container holding portion 21 can hold a plurality of containers C for accommodating the substrates S. The indexer robot 22 can enter the container C held by the container holding unit 21, and take out an unprocessed substrate S from the container C or store a processed substrate in the container C. As the container C, a FOUP (Front Opening Unified Pod), a SMIF (Standard Mechanical Interface) Pod, an OC (Open Cassette), or the like that accommodates a plurality of substrates S in a sealed state can be applied. In each container C, the plurality of substrates S are accommodated in a substantially horizontal posture.

The indexer robot 22 includes: a base part 221 fixed to the apparatus housing; a multi-joint arm 222 provided rotatably about a vertical axis with respect to the base portion 221; and a hand 223 attached to the distal end of the articulated arm 222. The hand 223 is configured to place and hold the substrate S on the upper surface thereof. Since an indexer robot having such an articulated arm and a substrate holding hand is well known, a detailed description thereof will be omitted.

The substrate processing section 10 includes: a center robot 15 arranged substantially at the center in a plan view; and a plurality of substrate processing units disposed so as to surround the center robot 15. Specifically, a plurality of (4 in this example) substrate processing units 11A, 12A, 13A, and 14A are disposed facing the space where the center robot 15 is disposed. The substrate processing units 11A to 14A perform predetermined processes on the substrate S. When the processing units have the same function, a plurality of substrates can be processed in parallel. Further, it is also possible to combine processing units having different functions and sequentially perform different processes on 1 substrate.

As will be described later, the substrate processing apparatus 1 according to this embodiment is used for a series of processes in which a substrate S is subjected to a wet process by a predetermined processing liquid and then dried. For this purpose, 2 substrate processing units 11A and 12A out of the 4 substrate processing units are responsible for wet processing of the substrate S and have a structure for enabling the processing therein. The other 2 substrate processing units 13A and 14A are configured to perform a process (drying process) of removing the residual liquid from the substrate S after the wet process and drying the substrate S, and to perform the process therein.

In each of the substrate processing units 11A to 14A, a substrate processing main body for processing a substrate S is accommodated in a processing chamber in which a shutter is provided to be opened and closed on a side surface facing the center robot 15. That is, the substrate processing unit 11A includes a processing chamber 110 and a shutter 111 provided on a side surface of the processing chamber 110 facing the center robot 15. The shutter 111 is provided to cover an opening (not shown) provided in a side surface of the process chamber 110 facing the center robot 15. When the shutter 111 is opened, the opening is exposed, and the substrate S can be carried in and out through the opening. When the substrate S is processed in the processing chamber 110, the gas atmosphere in the processing chamber 110 is shut off from the outside by closing the shutter 111.

Similarly, the substrate processing unit 12A includes a process chamber 120, and a shutter 121 provided on a side surface of the process chamber 120 facing the center robot 15. The substrate processing unit 13A includes a processing chamber 130, and a shutter 131 provided on a side surface of the processing chamber 130 facing the center robot 15. The substrate processing unit 14A includes a processing chamber 140, and a shutter 141 provided on a side surface of the processing chamber 140 facing the center robot 15.

The group of substrate processing units arranged in the horizontal direction in this manner has a plurality of layers (2 layers in this example) arranged in the vertical direction. That is, as shown in fig. 1B, a substrate processing unit 11B is provided below the substrate processing unit 11A. The substrate processing unit 11B has the same structure and function as the substrate processing unit 11A. Further, a substrate processing unit 12B having the same configuration and the same function as those of the substrate processing unit 12A is provided below the substrate processing unit 12A. Similarly, a substrate processing unit 13B (fig. 2) is provided below the substrate processing unit 13A, and a substrate processing unit (not shown) is provided below the substrate processing unit 14A. The number of layers of the substrate processing unit is arbitrary, and is not limited to 2 layers exemplified here. The number of substrate processing units disposed per 1 layer is not limited to the above.

Fig. 2 is a diagram showing the structure and installation environment of the center robot. The center robot 15 can receive an unprocessed substrate S from the indexer robot 22 and can transfer a processed substrate S to the indexer robot 22. More specifically, the center robot 15 includes a base portion 151, an elevation base 152, a rotation base 153, an extension arm 154, and a hand portion 155. The base unit 151 is fixed to a bottom frame of the substrate processing unit 10, and supports each configuration of the center robot 15. The elevating base 152 is attached to the base part 151, and a rotating base 153 is attached to an upper part of the elevating base 152. The lifting base 152 is vertically extendable and retractable, and the rotating base 153 is lifted and lowered by the extension and retraction motion.

The spin base 153 is rotatable about a vertical axis with respect to the lift base 152. A base portion of the telescopic arm 154 is attached to the rotating base 153, and a hand 155 is attached to a distal end portion of the telescopic arm 154. The telescopic arm 154 is horizontally telescopic within a predetermined range. Hand 155 is as follows: the substrate S can be placed and held on the upper surface thereof, and can be transferred to and from the hand 223 of the indexer robot 22. Since the hand mechanism having such a configuration is well known, a detailed description thereof will be omitted.

The substrate S held by the hand 155 can be moved horizontally by extending and contracting the telescopic arm 154 in the horizontal direction. Further, the direction of the horizontal movement of the substrate S can be defined by the rotation of the spin base 153 relative to the elevation base 152. The elevation base 152 elevates the spin base 153, thereby adjusting the height of the substrate S, i.e., the vertical position.

In the substrate processing apparatus 1 configured as described above, the substrate S is processed as follows. In the initial state, unprocessed substrates S are accommodated in the container C placed on the container holding portion 21. The indexer robot 22 takes out 1 unprocessed substrate S from the container C and delivers it to the center robot 15. The center robot 15 carries the received substrate S into a substrate processing unit that performs processing on the substrate S.

For example, when the substrate S is loaded into the substrate processing unit 11A, as shown in fig. 2, the center robot 15 adjusts the height of the spin base 153 by the elevating base 152, and positions the substrate S held by the hand 155 at the height of the shutter 111 on the side surface of the processing chamber 110 of the substrate processing unit 11A. The shutter 111 is opened, and the telescopic arm 154 is extended toward the opening on the side surface of the processing chamber 110, thereby carrying the substrate S into the processing chamber 110. After the telescopic arm 154 is retracted, the shutter 111 is closed, and the substrate S is processed in the processing chamber 110. The substrate S may be carried into another substrate processing unit in the same manner.

On the other hand, when the processed substrate S is taken out from the substrate processing unit 11A, the telescopic arm 154 enters the processing chamber 110 in which the shutter 111 is opened and takes out the processed substrate S. The substrate S taken out may be carried into another substrate processing unit to perform a new process, or may be returned to the container C via the indexer robot 22. The specific processing procedure of this embodiment will be described in detail later.

As shown in fig. 2, the center robot 15 is provided in a conveyance space TS laterally and upwardly separated from the external space by a partition wall 101. The substrate processing unit 11A is attached to a side portion of the partition wall 101 such that a side surface of the processing chamber 110 on which the shutter 111 is provided faces the transfer space TS. The same applies to other substrate processing units.

In addition to the above, the substrate processing apparatus 1 is provided with a control unit 90 for controlling the operations of the respective parts of the apparatus. The control Unit 90 includes at least a CPU (Central Processing Unit) 91 and a memory 92. The CPU91 executes a control program prepared in advance, thereby causing each unit of the apparatus to perform a predetermined operation. The memory 92 stores a control program to be executed by the CPU91, data generated by the execution, and the like. The operations of the indexer robot 22 and the center robot 15, the opening and closing of the gates of the respective processing chambers, the various processes on the substrate S, and the like are controlled by the CPU91 executing a control program.

Fig. 3A to 3C are diagrams illustrating a substrate processing unit performing wet processing. More specifically, fig. 3A is a diagram showing the structure of the substrate processing unit 11A, and fig. 3B and 3C are diagrams for explaining the operation of the substrate processing unit 11A. The structure of the substrate processing unit 11A will be described here, but the structures of other substrate processing units 11B, 12A and the like that perform wet processing are also basically the same.

The substrate processing unit 11A includes a wet processing unit 30 as a substrate processing main body in the processing chamber 110. The wet processing unit 30 supplies a processing liquid to the upper surface of the substrate S to perform surface processing, cleaning, and the like of the substrate S. In addition, the wet processing unit 30 is configured to collectively perform the solidification process for facilitating the conveyance of the substrate S after the wet processing. The solidification process is a process of covering the upper surface of the substrate S with a liquid film to solidify the substrate S, and covering the upper surface of the substrate S with a solidified film.

For this purpose, the wet processing unit 30 includes a substrate holding unit 31, a splash shield 32, a processing liquid supply unit 33, a solidification liquid supply unit 35, and a cooling gas supply unit 34. The action is controlled by the control unit 90. The substrate holding portion 31 includes a disk-shaped spin chuck 311 having substantially the same diameter as the substrate S, and a plurality of chuck pins 312 are provided at the peripheral edge portion of the spin chuck 311. The substrate S is supported by the chuck pins 312 abutting against the peripheral edge of the substrate S, and the spin chuck 311 can hold the substrate S in a horizontal posture with the substrate S separated from the upper surface thereof.

The spin chuck 311 is supported with its upper surface horizontal by a spin support shaft 313 extending downward from the center portion of its lower surface. The rotation support shaft 313 is rotatably supported by a rotation mechanism 314 attached to the bottom of the processing chamber 110. The rotation mechanism 314 incorporates a rotation motor not shown. The spin motor is rotated in accordance with a control instruction from the control unit 90, and the spin chuck 311 directly connected to the spin support shaft 313 is rotated about a vertical axis indicated by a chain line. In fig. 3A, the vertical direction is the vertical direction. Thereby, the substrate S rotates about the vertical axis in a horizontal posture.

A splash shield 32 is provided so as to laterally surround the substrate holding portion 31. The splash plate 32 has: a substantially cylindrical cup 321 provided so as to cover a peripheral edge portion of the spin chuck 311; and a liquid collecting portion 322 provided below the outer peripheral portion of the cup 321. The cup 321 is raised and lowered in accordance with a control command from the control unit 90. The cup 321 moves up and down between a lower position where the upper end portion of the cup 321 shown in fig. 3A is lowered below the peripheral portion of the substrate S held by the spin chuck 311 and an upper position where the upper end portion of the cup 321 shown in fig. 3B is positioned above the peripheral portion of the substrate S.

When the cup 321 is positioned at the lower position, as shown in fig. 3A, the substrate S held by the spin chuck 311 is exposed to the outside of the cup 321. Therefore, for example, the cup 321 is prevented from being an obstacle when the substrate S is carried in and out with respect to the spin chuck 311.

When the cup 321 is located at the upper position, as shown in fig. 3B, the peripheral edge of the substrate S held by the spin chuck 311 is surrounded. This prevents the processing liquid thrown off from the peripheral edge of the substrate S at the time of liquid supply described later from scattering into the chamber 110, and allows the processing liquid to be reliably collected. That is, droplets of the processing liquid thrown off from the peripheral edge of the substrate S by the rotation of the substrate S adhere to the inner wall of the cup 321 and flow downward, and are collected and collected by the liquid collecting unit 322 disposed below the cup 321. In order to recover the plurality of treatment liquids individually, the cups of the plurality of layers may be provided concentrically.

The processing liquid supply unit 33 has the following structure: a nozzle 334 is attached to the tip of an arm 333 extending horizontally from a rotation support shaft 332 provided rotatably with respect to a base 331 fixed to the processing chamber 110. The rotating support shaft 332 rotates in accordance with a control instruction from the control unit 90, and the arm 333 swings, and the nozzle 334 at the tip of the arm 333 moves between a retracted position retracted laterally from above the substrate S shown in fig. 3A and a processing position above the substrate S shown in fig. 3B.

The nozzle 334 is connected to a processing liquid supply source (not shown) provided in the control unit 90. When an appropriate processing liquid is supplied from the processing liquid supply source, the processing liquid is discharged from the nozzle 334 toward the substrate S. As shown in fig. 3B, the processing liquid Lq is supplied from the nozzle 33 positioned above the rotation center of the substrate S while the spin chuck 311 rotates the substrate S at a low speed, and the upper surface Sa of the substrate S is processed by the processing liquid Lq. As the processing liquid Lq, a liquid having various functions such as a developing solution, an etching solution, a cleaning solution, and a rinse solution can be used, and the composition is arbitrary. It is also possible to perform the treatment by combining a plurality of treatment liquids.

The solidification liquid supply unit 35 has a structure corresponding to the treatment liquid supply unit 33. That is, the coagulation liquid supply unit 35 includes a base 351, a pivot support shaft 352, an arm 353, a nozzle 354, and the like. The structure is the same as that of the corresponding member in the processing liquid supply portion 33. The rotation support shaft 352 rotates in accordance with a control instruction from the control unit 90, thereby rocking the arm 353. The nozzle 354 at the tip of the arm 353 supplies the solidification liquid for forming the solidified film to the upper surface Sa of the substrate S after the wet processing.

The operation of the solidification liquid supply unit 35 will be described by replacing the "treatment liquid Lq", "arm 333", and "nozzle 334" in the description of fig. 3B with the "solidification liquid Lq", "arm 333", and "nozzle 354", respectively. Unlike the treatment liquid, the solidification liquid is supplied to the upper surface Sa of the substrate S in a liquid state and then solidified to become a solid.

A fine uneven pattern (hereinafter, simply referred to as a "pattern") is formed on the upper surface Sa of the substrate to be processed. At this time, pattern collapse may occur due to the surface tension of the liquid entering the pattern during the drying of the wet substrate S after the wet process. As a method for preventing the pattern collapse, there are a method of replacing the liquid in the pattern with a liquid having a lower surface tension and drying the liquid, a sublimation drying method of coating the upper surface Sa of the substrate with a solid of a sublimable substance and sublimating the sublimable substance, a supercritical drying method employed in the present embodiment, and the like.

In order to perform supercritical drying processing requiring a high-temperature and high-pressure state, a high-pressure chamber different from a chamber for performing wet processing is required. Therefore, the substrate S after the wet processing needs to be transferred to the high-pressure chamber. In order to avoid collapse due to exposure of the pattern during conveyance, it is desirable to cover the substrate upper surface Sa with a liquid or a solid. Here, the conveyance of the substrate S with the liquid film covering the substrate S requires special consideration for the treatment of the substrate S on which the liquid film is placed. Further, there is a possibility that the pattern is exposed or the liquid is scattered in the apparatus due to the dropping liquid during the conveyance. In view of these points, it is preferable to convey the substrate with the upper surface Sa of the substrate covered with a solid.

Therefore, in this embodiment, the substrate upper surface Sa is conveyed while being covered with the solidified film. The solidified film is formed as follows. As shown in fig. 3B, the solidification liquid Lq is supplied from the nozzle 354 while the substrate S is rotated at a predetermined rotation speed, whereby the substrate upper surface Sa is covered with the liquid film LF of the solidification liquid. The solidification liquid is desired to have good miscibility with the treatment liquid used in the wet treatment, a surface tension lower than that of the treatment liquid, and a solidification point close to room temperature. For example, when the treating liquid contains water as a main component, Isopropyl alcohol (IPA) is preferably used.

When the liquid film LF is formed on the upper surface Sa of the substrate in this manner, as shown in fig. 3C, the nozzle 344 of the cooling gas supply unit 34 is positioned above the rotation center of the substrate S instead of the nozzle 354. The cooling gas supply unit 34 has a structure in which a nozzle 344 is attached to a tip of an arm 343 extending horizontally from a rotation support shaft 342 provided rotatably with respect to a susceptor 341 fixed to the process chamber 110. Similarly to the treatment liquid supply unit 33, the pivot support shaft 342 pivots in accordance with a control command from the control unit 90, thereby pivoting the arm 343. In this way, the nozzle 344 at the tip of the arm 343 moves between a retracted position retracted laterally from above the substrate S and a processing position above the substrate S.

The nozzle 344 is connected to a cooling gas supply unit (not shown) provided in the control unit 90. The cooling gas G supplied from the cooling gas supply unit and having a temperature lower than the solidification point of the solidification liquid constituting the liquid film LF is ejected from the nozzle 344 toward the substrate S. Thereby, the liquid film LF on the substrate S is cooled from the surface side thereof. As shown in fig. 3C, the nozzle 344, which discharges the low-temperature cooling gas G toward the upper surface Sa of the substrate on which the liquid film LF is formed, moves in a scanning manner toward the outer periphery of the substrate S. Thus, the liquid film LF on the substrate upper surface Sa is sequentially solidified from the center portion, and finally, the entire liquid film LF on the substrate upper surface Sa is converted into a solidified film FF in which the solidified liquid is solidified.

Here, the entire solidification of the liquid film LF is not required in the present embodiment, as long as the solidification in the vicinity of the surface of the liquid film LF is sufficient. That is, the entire surface of the liquid film LF may be solidified to such an extent that it does not hinder conveyance, that is, to such an extent that it is not deformed by vibration or the like during conveyance. For example, the liquid film LF may be maintained in a liquid state between the solidified film FF and the substrate S. Since the entire solidification is not required, energy consumption and processing time for solidification can be reduced.

The process of covering the substrate S with the solidified film is not limited to the method of cooling the liquid film LF. For example, a method may be employed in which a liquid having a freezing point higher than room temperature and heated to a state of not less than the freezing point is supplied to the substrate S and solidified by natural cooling. In addition, a method may be employed in which a solution in which a substance having a freezing point higher than room temperature is dissolved in an appropriate solvent is supplied to the substrate S, and the solvent is volatilized and solidified. As this method, for example, a solution in which t-butyl alcohol (TBA) as a solidified substance is dissolved in IPA as a solvent can be used as a coagulating liquid.

The melting point (freezing point) of TBA is approximately room temperature (25.5 ℃). When a liquid film is formed on the substrate S by a solution in which TBA is dissolved in IPA solvent, a solidified film is formed from the vicinity of the surface of the liquid film as the IPA solvent on the surface evaporates. This can maintain a layer of a liquid solution between the substrate S and the solidified film FF.

In this way, the substrate S carried out in a state where the upper surface Sa is covered with the solidified film FF is carried to the substrate processing unit 13A and subjected to the drying process. That is, the substrate processing unit 13A has a function of performing, as substrate processing, drying processing for removing the solidified film FF formed on the upper surface Sa of the substrate S carried in a horizontal posture and drying the substrate S. As the drying process, supercritical drying is applied in which the substrate S is covered with a supercritical fluid and then the supercritical fluid (not via a liquid phase) is vaporized and removed. Here, the configuration of the substrate processing unit 13A will be described, and the configurations of the other substrate processing units 13B, 14A and the like that perform the drying process are also basically the same.

Fig. 4 is a diagram showing a substrate processing unit that executes a supercritical drying process. More specifically, fig. 4 is a side sectional view showing the internal structure of the substrate processing unit 13A. Since the principle of the supercritical drying process and the basic structure thereof are well known, a detailed description thereof will be omitted. The substrate processing unit 13A has a high-pressure chamber 130, and a drying processing unit 40 as a main body of performing a drying process is provided inside thereof. In the drying processing unit 40, a stage 41 for placing the substrate S is provided in the high-pressure chamber 130. The stage 41 holds the substrate S whose upper surface Sa is covered with the solidified film by suction holding or mechanical holding. Since the high pressure chamber 130 has a high pressure, the internal structure is simple to withstand the high pressure, and a member capable of withstanding the high pressure is used.

In the center of the lower surface of the platform 41, a rotation support shaft 42 extends downward. The rotation support shaft 42 is inserted through the bottom surface of the high-pressure chamber 130 via the high-pressure seal rotation introduction mechanism 43. The rotary shaft 431 of the high-pressure seal rotation introduction mechanism 43 is connected to the rotary mechanism 432. Therefore, when the rotation mechanism 432 is operated in accordance with a control command from the control unit 90, the substrate S is rotated together with the stage 41 about the rotation axis in the vertical direction shown by the dashed-dotted line.

Inside the high pressure chamber 130, a fluid dispersion member 44 is disposed above the stage 41. The fluid dispersing member 44 is provided with a plurality of through holes 442 penetrating vertically through the flat plate-like clogging plate 441. Carbon dioxide gas is supplied from the carbon dioxide supply unit 45 to the upper portion of the high-pressure chamber 130 as needed. The carbon dioxide gas is rectified by the fluid dispersing member 44 and is uniformly supplied to the substrate S from above the substrate S.

Further, nitrogen is introduced into the high-pressure chamber 130 from the nitrogen supply portion 46 as necessary. Nitrogen is supplied in various forms as required. That is, according to the purpose of purging the gas in the high-pressure chamber 130 or cooling the chamber, the gas is supplied into the high-pressure chamber 130 as a gas at normal temperature or after temperature rise or liquid nitrogen liquefied as cooling.

The solution is supplied from the solution supply unit 47 into the high-pressure chamber 130 as necessary. The dissolving liquid is a liquid for dissolving the solidified film FF, and is supplied to the upper surface Sa of the substrate S carried in with the solidified film FF formed thereon. The solution may be a solution having miscibility with the solidification solution that is a liquid constituting the solidified film FF, and is more preferably a solution having a surface tension equal to or lower than that of the solidification solution. For example, when the solidification liquid includes IPA, an organic solvent such as IPA or acetone, or a supercritical fluid such as supercritical carbon dioxide that can dissolve IPA can be used as the solution.

In addition, as will be described later, in this embodiment, since the carbon dioxide gas introduced into the high-pressure chamber 130 is pressurized and liquefied and then converted into a supercritical fluid, when the carbon dioxide gas is used as the solution, it is not necessary to provide a separate solution supply unit 47.

Further, the discharge mechanism 48 is connected to the high-pressure chamber 130. The discharge mechanism 48 has a function of discharging various fluids such as gas and liquid introduced into the high-pressure chamber 130 as necessary. The discharge mechanism 48 has piping, a nozzle, a pump, and the like provided thereto. Thereby, the fluid in the high pressure chamber 130 can be quickly discharged if necessary.

Although not shown, the control unit 90 has a structure for detecting the pressure or temperature in the high-pressure chamber 130 and a structure for controlling them to predetermined values. That is, the control unit 90 has a function of controlling the pressure and temperature in the high-pressure chamber 130 to predetermined target values.

Next, the operation of the substrate processing apparatus 1 configured as described above will be described. As described above, the substrate processing apparatus 1 is an apparatus that sequentially performs wet processing and dry processing on a substrate S. The main flow of this process is as follows. That is, after the substrate S is transferred to the substrate processing unit that performs the wet processing and the processing liquid is processed, the solidified film of the solidified liquid is formed, and the substrate S is transferred to the substrate processing unit that performs the drying processing and the solidified film is removed, and the substrate S is dried. The specific processing contents will be described below.

Here, the description will be made with respect to 1 substrate S, the substrate processing unit 11A performs wet processing, and the substrate processing unit 13A performs dry processing. However, the combination of the substrate processing unit that performs the wet processing and the substrate processing unit that performs the dry processing is arbitrary and is not limited thereto. In the following description, the substrate processing unit 11A and the like that perform wet processing will be referred to as a "wet processing unit" for the sake of clarity of the operation of each substrate processing unit. The substrate processing unit 13A and the like that perform the drying process are referred to as a "drying process unit".

Fig. 5 is a flowchart showing the operation of the substrate processing apparatus. This operation is realized by the CPU91 executing a control program prepared in advance to cause each unit of the device to perform a predetermined operation. First, the indexer robot 22 takes out 1 unprocessed substrate S from one of the containers C that store unprocessed substrates (step S101). Then, the substrate S is transferred from the indexer robot 22 to the center robot 15 (step S102). The center robot 15 carries the substrate S into the substrate processing unit (wet processing unit) 11A that performs wet processing (step S103).

The substrate processing unit 11A into which the substrate S is carried performs wet processing on the substrate S (step S104). As described above, the wet processing is performed by supplying the processing liquid to the substrate S to process and clean the upper surface Sa of the substrate. The substrate S after the wet processing is subjected to a solidification process for forming a solidified film FF (step S105).

Fig. 6 is a flowchart showing the coagulation process. In the solidification process, an organic solvent such as IPA is supplied as a solidification liquid from a nozzle 354 of the solidification liquid supply unit 35 disposed above the rotation center of the substrate S to the wet-processed substrate upper surface Sa. Thereby, the processing liquid remaining on the substrate upper surface Sa is replaced with the solidification liquid, and a liquid film LF of the solidification liquid is formed on the substrate upper surface Sa (step S201). Next, the liquid film LF is cooled and solidified by the scanning movement of the nozzle 344 that discharges the cooling gas along the substrate upper surface Sa, thereby forming a solidified film FF (step S202).

Returning to fig. 5, the substrate S on which the solidified film FF is formed on the upper surface Sa by the solidification process is taken out from the substrate processing unit 11A by the center robot 15 (step S106). Then, the substrate S is carried into the substrate processing unit (drying unit) 13A that performs the drying process (step S107).

The substrate processing unit 13A into which the substrate S is carried performs a drying process on the substrate S. That is, the liquid adhering to the substrate S is removed to dry the substrate S (step S108). The drying process will be described later. The processed substrate S is taken out from the substrate processing unit 13A by the center robot 15 (step S109). The taken-out processed substrate S is delivered from the center robot 15 to the indexer robot 22 (step S110). The indexer robot 22 accommodates the substrate S in one of the containers C (step S111). The container C for storing the processed substrate S may be a container for storing the unprocessed substrate S, or may be another container.

If there is a substrate to be processed (yes in step S112), the process returns to step S101, and the above-described process is executed on the subsequent substrate S, and if there is no substrate to be processed (no in step S112), the process ends.

The flow of processing 1 substrate S has been described above, and processing of a plurality of substrates is executed in parallel in an actual apparatus. That is, while 1 substrate S is being processed in 1 substrate processing unit, at least 1 of the conveyance of another substrate by the indexer robot 22 and the center robot 15 and the substrate processing by the other substrate processing unit can be simultaneously performed in parallel.

More specifically, for example, after the substrate S is transferred from the indexer robot 22 to the center robot 15 in step S102, the indexer robot 22 can enter a new container C and take out another substrate. Further, for example, after 1 substrate S is carried into the substrate processing unit 11A in step S103, the indexer robot 15 can carry other substrates into the other substrate processing unit or carry other substrates processed by the other substrate processing unit.

Therefore, when it is necessary to sequentially process a plurality of substrates S, the plurality of substrates S are processed in parallel by appropriately adjusting the operation order of each part of the apparatus for processing each substrate S. This enables the substrate processing apparatus 1 to have a processing capability as a whole. The specific operation sequence needs to be set as appropriate according to the specification of the process, the required time of each step, whether or not the simultaneous processes are possible, and the like.

Fig. 7 is a flowchart showing the drying process. The substrate processing unit (drying processing unit) 13A receives the substrate S with the upper surface Sa covered with the solidified film FF and performs drying processing. As described above, the supercritical drying treatment using the supercritical fluid is performed here. More specifically, first, the solution supply unit 47 supplies a solution to the substrate upper surface Sa to dissolve the solidified film FF (step S301).

When the dissolving liquid is the same as the material constituting the solidified film FF, the substrate upper surface Sa returns to a state before being carried out of the wet processing unit 11A, that is, a state in which the upper surface Sa is covered with the liquid film LF of the solidified liquid. For example, the solidified film FF is formed by IPA, and the dissolving liquid is also IPA.

On the other hand, when the dissolving solution is a solution having a property of dissolving the solidifying solution, which is different from the material of the solidifying film, the substrate upper surface Sa is covered with a liquid film of a mixed solution of the solidifying solution and the dissolving solution. Further, by supplying the solution, the solidification liquid remaining on the upper surface Sa of the substrate can be replaced with the solution.

Then, when the liquid film is spun off by the rotation of the substrate S (step S302), most of the solution on the upper surface Sa of the substrate is removed, but the solution remains in the pattern. The thrown-off liquid is discharged through the discharge mechanism 48. In this state, carbon dioxide is introduced from the carbon dioxide supply unit 45 into the high-pressure chamber 130.

The carbon dioxide gas is supplied to the high-pressure chamber 130 to sufficiently increase the internal pressure of the chamber, thereby liquefying the carbon dioxide. Alternatively, liquid carbon dioxide may be introduced into the high pressure chamber 130. The liquid carbon dioxide covers the upper surface Sa of the substrate. The liquefied carbon dioxide dissolves the organic solvent well. Therefore, the solution such as IPA remaining in the pattern is replaced with liquid carbon dioxide (step S303).

In the case of using liquid carbon dioxide as the dissolving liquid, the supply of carbon dioxide in step S303 is intended to create a supercritical state, not to replace it.

Next, the temperature and pressure in the high-pressure chamber 130 are adjusted to conditions under which carbon dioxide is in a supercritical state. Thereby, the carbon dioxide in the high-pressure chamber 130 becomes a supercritical fluid (step S304). The fluid in the supercritical state has extremely high fluidity and extremely low surface tension. In particular, the supercritical fluid generated from carbon dioxide dissolves an organic solvent such as IPA or acetone satisfactorily. Therefore, the supercritical fluid of carbon dioxide enters deep into the fine pattern, and the remaining organic solvent component is carried away from the inside of the pattern. One reason why carbon dioxide is suitable for supercritical drying is that carbon dioxide is in a supercritical state at a relatively low pressure and low temperature.

Then, the pressure inside the high-pressure chamber 130 is sharply reduced (step S305). Thereby, the supercritical fluid is directly vaporized without passing through the liquid phase and is removed from the substrate S. Thereby, the substrate S is completely removed of the liquid component and is in a dry state. The liquid component remaining in the pattern is replaced with the supercritical fluid, and the supercritical fluid is directly vaporized, thereby avoiding the problem of pattern collapse due to the surface tension of the fluid in the pattern.

Thus, the liquid remaining in the pattern is finally replaced by the supercritical fluid. Therefore, it can be said that the solidified film FF formed during transportation does not necessarily have to be made of a low surface tension material. For example, even if the solidified film FF is formed from a liquid containing water as a main component, the above-described advantage can be obtained during transportation. However, since water has low solubility in liquid or supercritical carbon dioxide, the trigger is not preferable from the viewpoint of efficient substitution. Organic solvents such as IPA, acetone, etc., which show a high solubility for carbon dioxide, are generally lower in surface tension than water. Further, it is clear that the solidification solution and the dissolution solution are advantageous in view of the properties of the treatment because the surface tension is low.

As described above, in this embodiment, the upper surface Sa of the substrate S is covered with the liquid film in the wet processing unit 11A and solidified, and is directly conveyed in a solidified state. This improves convenience as compared with liquid conveyance, and prevents exposure of the upper surface Sa of the substrate due to liquid dropping during conveyance. On the other hand, in the drying unit 13A that receives the substrate S, the substrate S is dried by supercritical fluid replacement after the solidified film is once dissolved, without leaving liquid components and without causing pattern collapse.

In this way, in the present embodiment, the substrate is dried by conveying and removing the solidified film in a state where the solidified film is formed on the substrate. It can be said that the processing contents are similar to the sublimation drying processing which is the related art that is removed by sublimating the solidified film formed of the sublimable substance. However, in the present embodiment, a process is employed in which the solidified film is dissolved and returned to a liquid state, and then the substitution and drying are performed by the supercritical fluid. This also considers the following, rather than simply facilitating transport.

Fig. 8A to 8C are diagrams schematically showing problems that may occur in the solidified film. As shown in fig. 8A, a plurality of fine patterns PT are formed on the upper surface Sa of the substrate S in proximity to each other, and after the wet treatment, the fine patterns PT are covered with a liquid film LF of the solidification liquid. Here, the interval between adjacent patterns PT is referred to as a gap size GS. The liquid film LF is solidified by supplying a cooling gas having a temperature lower than the solidification point thereof to the liquid film LF. However, if the gap size GS is small, the following problem occurs.

In the liquid entering the minute space, there is a phenomenon that the freezing point is sharply lowered. For example, in the case of water, as shown in fig. 8B, the freezing point of water is 0 ℃ in a sufficiently wide space (large gap size GS). However, the freezing point gradually decreases in a narrow gap of, for example, 100nm or less, and for example, if the gap size GS is about 1nm, the freezing point decreases to about (-50) ° C. It is found that the liquid film material is similarly apt to be IPA, which is generally used.

When a liquid film containing water as a main component is desired to be solidified, a cooling gas having a sufficiently low temperature compared with the freezing point (0 ℃) of free space is used. As the temperature Tg, it is considered that it is realistic to use, for example, about (-5) to (-20) DEG C. However, fig. 8B shows a case where the liquid in the gap cannot be solidified at the temperature Tg if the gap size is on the order of nanometers.

As a result, as shown in fig. 8C, even if the surface of the liquid film LF is converted into the solidified film FF by cooling, there is a possibility that the liquid film LF is in a liquid state directly in the deep portion of the pattern depending on the cooling temperature and time. If this phenomenon occurs in the sublimation drying process, the drying proceeds by a phase change from a liquid phase to a gas phase, which is not desirable. Thus, the purpose of preventing pattern collapse due to the surface tension of the liquid cannot be achieved.

In the present embodiment, the solidified film is dissolved and then replaced with the supercritical fluid and removed, and therefore, such a problem does not occur. That is, in the present embodiment, the solidified film is conveyed in a state where it is formed, and after the conveyance, the solidified film is dissolved and then subjected to supercritical drying treatment. This process is simple and easy to handle, and can reliably prevent collapse even in a very fine pattern.

In other words, in the treatment of this embodiment, the solidified film may be solidified to such an extent that the surface thereof does not flow, and it is not necessary to completely solidify the solidified film to the depth of the pattern, for the convenience of transportation. This means that the conditions in the temperature and the treatment time when the liquid film LF is cooled are less than those when the liquid film is completely solidified. Therefore, the energy required for cooling can be reduced, and the cooling time can be shortened. In addition, the following modification can be established from the viewpoint that the surface layer of the liquid film solidifies and the deep portion can be in a liquid state.

Fig. 9 is a flowchart showing another example of the solidification processing. Fig. 10 is a view schematically showing the state of the liquid film according to this modification. The processing shown in fig. 9 is performed as processing applied to step S105 of fig. 5, and may be performed instead of the coagulation processing of fig. 6. In this modification, when forming the solidified film, first, a filling liquid film F1 for filling the inside of the pattern with a liquid is formed (step S401). For the purpose of filling the filling liquid film F1 in the pattern, solidification is not required for the above reasons. Therefore, the freezing point is not limited as long as a substance having a sufficiently small surface tension is selected. Materials that do not solidify at the cooling temperature may also be selected intentionally. The thickness of the liquid film F1 may be about the same as the height of the pattern PT.

Next, a solidification liquid film F2 of the solidification liquid is formed so as to cover the filling liquid film F1 (step S402). The solidification liquid film F2 is not restricted by surface tension, and a material that is easily solidified can be selected and used. The filling liquid film F1 and the solidifying liquid film F2 may not be mixed. The thus formed liquid films F1 and F2 are supplied with a cooling gas to solidify the solidification liquid film F2 (step S403).

Here, for example, if the freezing point of the liquid constituting the filling liquid film F1 is at least room temperature and the freezing point of the liquid constituting the solidifying liquid film F2 is at most room temperature, the solidifying liquid film F2 can be solidified without particularly cooling. However, the liquid constituting the solidifying liquid film F2 needs to be liquid at the time of supply to the substrate S, and may be supplied in a state heated to a temperature slightly higher than the solidifying point, for example.

In this modification, similarly to the above-described embodiment, there is obtained an advantage that convenience in carrying is improved by solidifying the solidification liquid film F2. Further, the cooling temperature can be set higher than that in the conventional art, thereby reducing the energy consumption. On the other hand, since the filling liquid film F1 is in a liquid state that is not completely solidified, it is easy to remove the filling liquid film after transportation. Further, the pattern protecting effect in the conveyance covered with the liquid film also sufficiently acts. In addition, the degree of freedom in selecting the liquid film forming material also increases.

In addition, the following differences are also found in comparison between the present embodiment and the sublimation drying process of the related art. In the prior art, a solidified film covering a substrate is formed by a sublimable substance. Since the sublimable substance has high volatility, the substrate surface may be exposed when the sublimable substance is used during transportation. In addition, the volatilized sublimates may be scattered and re-precipitated in the apparatus, and may become a contamination source for the apparatus or the substrate being processed. Alternatively, it may be necessary to take measures to prevent the scattered substances from leaking out of the apparatus. On the other hand, in the present embodiment, since the sublimation property is not required for the solidified film, the possibility of occurrence of such a problem is greatly reduced.

As described above, in the above embodiment, the substrate processing unit 11A or the like as a wet processing unit functions as the "first processing unit" of the present invention, and the substrate processing unit 13A or the like as a dry processing unit functions as the "second processing unit" of the present invention. The center robot 15 functions as a "conveyance mechanism" of the present invention. The high-pressure chamber 130 functions as a "chamber" of the present invention, and the carbon dioxide supply unit 45 functions as a "fluid supply unit" of the present invention.

The present invention is not limited to the above embodiments, and various modifications other than those described above may be made without departing from the spirit of the invention. For example, the above embodiment is an embodiment of a processing system in which the substrate processing unit 11A, the substrate processing unit 13A, and the central robot 15, which correspond to the "first processing unit", the "second processing unit", and the "transfer mechanism" of the present invention, are integrally housed in 1 housing. However, the present invention can also be applied to a processing system having a first processing unit and a second processing unit provided independently of each other, and a transfer mechanism for transferring a substrate therebetween.

Various chemical substances used in the above embodiments are examples of some of them, and various substances may be used instead of them in keeping with the technical idea of the present invention.

In the above description of the embodiment, the possibility that the liquid entering the deep part of the uneven pattern is not solidified is described. However, the above process is itself true regardless of whether the liquid in the pattern is completely solidified. In order to ensure that the inside of the pattern is in a liquid state, for example, the temperature of the cooling gas may be set to be lower than the freezing point of the free space of the liquid constituting the liquid film and higher than the freezing point corresponding to the gap size of the pattern of the substrate to be processed.

The substrate processing method of the present invention may be implemented as a control program executed by a computer that controls a substrate processing apparatus having a predetermined configuration. Further, the embodiment of the present invention may be distributed by a recording medium on which the control program is recorded in a form readable by a computer in a non-transitory manner.

As described above, in the substrate processing method according to the present invention, as exemplified and described in the specific embodiments, for example, a solidified film may be formed by cooling at least the surface of the liquid film. In the present invention, the liquid film does not need to be entirely solidified, and may be solidified to such an extent that the surface thereof is suitable for transportation. Therefore, the method of cooling the surface of the liquid film and the vicinity thereof to form a solidified film is effective in terms of thermal efficiency.

In this case, for example, in the step of drying the substrate, the substrate may be dried using a supercritical fluid. According to this structure, the residual liquid inside the pattern can be removed by supercritical fluid replacement with extremely low surface tension. Therefore, even a substrate having a fine uneven pattern can be dried satisfactorily.

For example, the second processing unit may have a chamber for receiving the substrate, and the substrate may be dried by replacing the dissolving liquid with a liquid low surface tension liquid in the chamber and then vaporizing the low surface tension liquid from the supercritical fluid state. The low surface tension liquid described herein is a liquid having a surface tension lower than that of the dissolving liquid. According to this configuration, since the substrate is dried by vaporizing the liquid having a surface tension lower than that of the original liquid in a supercritical state, pattern collapse due to the presence of the liquid phase can be effectively suppressed.

In this case, carbon dioxide may be used as the supercritical fluid. The supercritical conditions of carbon dioxide are relatively low temperature and low pressure among substances in a supercritical state. Therefore, the apparatus for realizing the supercritical state can be configured in a small scale, and therefore, the processing cost can be suppressed. In addition, since carbon dioxide in a supercritical state favorably dissolves an organic solvent, it is suitable for removing organic solvent components remaining on the substrate.

For example, at least the surface of the liquid film may be converted into a solidified film by cooling, and a part of the liquid film may be maintained in a liquid state between the solidified film and the substrate. In the present invention, the solidified film is formed to improve the portability of the substrate while protecting the pattern, and the solidified film is dissolved after the transportation. Therefore, the liquid film of the protective pattern may be in a liquid state. By not solidifying the entire liquid film, energy and processing time required for solidification can be reduced.

For example, the liquid film may contain an additive having a melting point equal to or higher than that at room temperature, in addition to the organic solvent. According to this configuration, since the additive is solidified by evaporation of the organic solvent from the surface of the liquid film to form a solidified film, the structure and the treatment for cooling can be omitted in a normal use environment. As a suitable substance for such an additive, for example, t-butanol can be used. Here, "normal temperature" means in a broad sense 5 ℃ to 35 ℃ and more narrowly 15 ℃ to 25 ℃ according to the Japanese Industrial Standard defined as "JIS Z8703". In actual use, the ambient temperature in the environment in which the substrate processing apparatus of the present invention is installed can be regarded as "normal temperature".

For example, at least one of the organic solvent and the solvent contained in the liquid film may be isopropyl alcohol or acetone. The surface tension of the liquid is lower than that of, for example, a liquid mainly composed of water, and is suitable for the purpose of the present invention.

For example, the liquid film may be formed by forming a filling liquid film filling the inside of the uneven pattern and a solidifying liquid film covering the filling liquid film with a material different from the filling liquid film, and cooling the liquid film to a temperature lower than the solidifying point of the liquid constituting the solidifying liquid film to solidify the solidifying liquid film. According to this structure, the solidified film covering the inside of the projection and depression pattern is formed in a state where the filling liquid film is filled therein. This ensures convenience in transportation and enables effective removal of the solidified film thereafter. Further, different materials can be used for the filling liquid film and the solidifying liquid film, and the degree of freedom in material selection and setting of the treatment conditions is increased.

In this case, for example, a liquid having a freezing point of not more than room temperature may be used as the liquid constituting the filling liquid film, and a liquid having a freezing point of not less than room temperature may be used as the liquid constituting the solidifying liquid film. According to this configuration, no special apparatus or treatment is required to achieve coexistence of the solidified film and the liquid film in the usage environment at room temperature.

In the substrate processing apparatus of the present invention, the second processing unit may further include a solution supply unit configured to supply an organic solvent as the solution to the solidified film. With this structure, the solidified film can be dissolved in an organic solvent, and the substrate can be easily restored to a state in which the substrate is covered with the liquid film.

While the invention has been described in terms of specific embodiments, the description is not intended to be construed in a limiting sense. Various modifications of the disclosed embodiments will be apparent to those skilled in the art from the description of the invention, as well as other embodiments of the invention. Therefore, the scope of the claims is to be construed as including the modifications or embodiments within a range not departing from the true scope of the invention.

Industrial applicability of the invention

The present invention is applicable to the entire substrate processing technology including a process of conveying a substrate in a state covered with a solidified film, and drying the substrate by removing the solidified film at a conveyance destination. The method is particularly suitable for processing a substrate having a fine uneven pattern.

Description of the reference numerals:

1 substrate processing apparatus

11A Wet processing Unit and substrate processing Unit (first processing Unit)

13A drying unit, substrate processing unit (second processing unit)

15 center manipulator (carrying mechanism)

130: high pressure chamber (Chamber)

FF: solidifying film

LF: liquid film

PT: pattern (concave convex pattern)

S: substrate