JP2013030612A - Substrate processing apparatus and substrate processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit frost from adhering to a nozzle and prevent contamination of a substrate due to the frost in a substrate processing apparatus and a substrate processing method which cool and solidify a liquid film formed on the substrate.SOLUTION: In a retreated position retreated from a substrate in a lateral direction, a flow straightening member 37, having an upper surface 37a formed into a flat surface, is disposed in the vicinity of a gas discharge port 30 of a cooling gas nozzle 3 facing the gas discharge port 30, and a small amount of a cooling gas is discharged from the gas discharge port 30. Performing idling that discharges the cooling gas even when the apparatus is not used suppresses the nozzle temperature rise and allows the cool temperature cooling gas to be discharged immediately at the time of need. Further, disposing the flow straightening member 37 and jetting the cooling gas from a gap around the gas discharge port 30 during the idling inhibits ambient atmosphere, having high humidity, from intruding in the nozzle and prevents frost from adhering to the nozzle.

Description

  The present invention relates to a substrate processing apparatus and a substrate processing method for executing processing including a process of cooling and solidifying a liquid film formed on a substrate.

  Conventionally, for the purpose of removing contaminants such as particles adhering to the substrate surface, for example, there is a technique of forming a liquid film on the substrate surface and cooling and solidifying it. For example, in the technique described in Patent Document 1 previously disclosed by the applicant of the present application, the liquid film is frozen by moving a nozzle that discharges a low-temperature cooling gas to the liquid film formed on the substrate surface, By washing away this with a rinsing liquid, contaminants such as particles adhering to the substrate together with the frozen film are removed.

Japanese Patent Laying-Open No. 2008-071875 (for example, FIG. 7)

  In this type of technology, the cooling gas discharge nozzle is made to stand by at a retreat position away from the substrate, and when the process of freezing the liquid film is performed, the nozzle is moved above the substrate. At this time, the frost adhered to the nozzle during the standby may fall on the substrate to generate a watermark, or the substrate may be contaminated by a contaminant contained in the frost. The generation of frost is mainly caused by a high humidity ambient atmosphere entering the inside of the nozzle that has been cooled by contact with a low temperature gas. In the prior art, sufficient consideration has not been given to such a problem.

  The present invention has been made in view of the above problems, and in a substrate processing apparatus and a substrate processing method for cooling and solidifying a liquid film formed on a substrate, it is possible to suppress frost from adhering to a nozzle, and An object is to provide a technique capable of preventing contamination.

  In order to achieve the above object, the substrate processing apparatus according to the present invention has a substrate holding means for holding a substrate having a liquid film formed on the surface thereof substantially horizontally and a temperature lower than a freezing point of the liquid constituting the liquid film. A cooling gas discharge nozzle that discharges the cooling gas from a gas discharge port that opens downward, and the cooling gas discharge nozzle is moved relative to the substrate held by the substrate holding means to thereby move the cooling gas discharge nozzle. Is moved along the surface of the substrate, and the cooling gas discharge nozzle can be positioned at a retracted position away from above the substrate, and the cooling gas discharge nozzle positioned at the retracted position is A rectifying member that is disposed below the gas discharge port and whose upper surface is a nozzle facing surface that is larger than the opening of the gas discharge port, the cooling gas discharge nozzle A predetermined amount of the cooling gas is discharged from the gas discharge port while being positioned at the retreat position, and the nozzle facing surface of the rectifying member is disposed close to the gas discharge port. Yes.

  In order to achieve the above object, the substrate processing method according to the present invention includes a step of forming a liquid film on the surface of the substrate and a cooling gas discharge nozzle having a gas discharge port that opens downward from above the substrate. Moving the liquid film from the retracted position to above the substrate on which the liquid film is formed, and moving the cooling gas discharge nozzle relatively along the substrate surface while moving the liquid film from the gas discharge port. Supplying a cooling gas having a temperature lower than the freezing point of the liquid constituting the liquid film to solidify the liquid film; and melting and removing the solidified body of the solidified liquid film, the gas discharge nozzle comprising: The nozzle facing surface of the rectifying member whose upper surface becomes a nozzle facing surface larger than the opening of the gas discharge port while discharging the cooling gas from the gas discharge port before moving the substrate upward. Is characterized in that arranged close to face the gas discharge port of the cooling gas discharge nozzle is in said retracted position.

  According to the knowledge of the inventors of the present application, the low-temperature cooling gas discharged from the gas discharge port has a large specific gravity, and thus forms a downward air flow that goes vertically downward. Along with this, a vortex of the airflow is generated around the gas discharge port and the surrounding atmosphere is entrained, so that frost is generated inside the cooling gas discharge nozzle. This tendency is particularly remarkable when the flow rate of the cooling gas is small. In addition, even when the discharge of the cooling gas is completely stopped, the cooled gas around the nozzle forms a descending airflow, which causes the same problem.

  Therefore, in the invention configured as described above, the rectifying member is disposed in close proximity to the gas discharge port of the cooling gas discharge nozzle in the retracted position, and the cooling gas is discharged from the gas discharge port in this state. By doing so, the following effects can be obtained. That is, by discharging a certain amount of cooling gas even when the cooling gas discharge nozzle is in the retracted position, it is possible to generate an air flow from the inside of the nozzle to the outside, thereby restricting the intrusion of the atmosphere from the outside. it can. At this time, since the nozzle facing surface of the rectifying member larger than the opening is opposed to the lower side of the gas discharge port that opens downward, the airflow flowing downward from the gas discharge port is opposed to the peripheral edge of the gas discharge port and the nozzle. It is changed to the outward direction spreading from the gap to the surface to the surroundings. The lower part of the gas discharge port is covered with the nozzle facing surface.

  In this way, by forming an air flow that blows outward from the peripheral edge of the gas discharge port, the surrounding high-humidity atmosphere is prevented from entering the inside of the cooling gas discharge nozzle from the gas discharge port. Thereby, generation | occurrence | production of the frost in a nozzle can be prevented. In particular, by discharging the cooling gas with the nozzle facing surface close to the gas discharge port, the pressure inside the nozzle rises and the flow rate of the gas blown out from the gap increases, thereby preventing the surrounding atmosphere from entering the nozzle. Can be further increased.

  That is, according to the configuration of the present invention, it is possible to effectively prevent the ambient atmosphere of high humidity from entering the inside of the cooling gas discharge nozzle, thereby preventing the frost from adhering to the inside of the nozzle, and the substrate to be processed. It is possible to prevent the frost from falling and contaminating the substrate.

  In the substrate processing apparatus according to the present invention, for example, the gas discharge port of the cooling gas discharge nozzle in which the distance between the gas discharge port of the cooling gas discharge nozzle positioned at the retracted position and the nozzle facing surface is scanned and moved with respect to the substrate surface. And the distance between the substrate surface and the substrate surface may be smaller. Alternatively, for example, the area of the slit-shaped opening formed by the peripheral edge of the gas discharge port of the cooling gas discharge nozzle positioned at the retracted position and the nozzle facing surface is made smaller than the opening area of the gas discharge port. Also good. According to these configurations, the gas flow rate from the gas discharge port of the cooling gas discharge nozzle in the retracted position is equal to or higher than that during the scanning movement even if the gas flow rate is the same as that during the scanning movement. Therefore, it is possible to reliably prevent the ambient atmosphere from entering the nozzle and prevent frost from adhering to the nozzle. Further, since the gas flow rate necessary to obtain the same gas flow rate as that during the scanning movement is reduced, it is possible to reduce the amount of gas used necessary to prevent the ambient atmosphere from entering the nozzle.

  In the present invention, for example, the amount of cooling gas discharged from the gas discharge port in a state where the cooling gas discharge nozzle is positioned at the retracted position is cooled from the gas discharge port of the cooling gas discharge nozzle scanned and moved with respect to the substrate surface. The gas discharge amount may be smaller than this, and by doing so, the gas consumption amount can be suppressed while preventing the ambient atmosphere from entering the nozzle.

  In these substrate processing apparatuses, for example, the opening surface of the gas discharge port and the nozzle facing surface may both be horizontal planes. As described above, the low-temperature gas generates a downward airflow, but if the opening surface of the gas discharge port and the nozzle facing surface are both horizontal surfaces, the direction of the gas blown from these gaps is isotropic in the horizontal direction. Thus, the effect of blocking the ambient atmosphere isotropically generated, so that it is possible to reliably prevent the ambient atmosphere from entering the nozzle.

  Further, for example, the outer peripheral portion of the lower end of the cooling gas discharge nozzle is extended to the outside so as to surround the gas discharge port, and the nozzle facing surface of the rectifying member is made larger than the plane size of the flange portion. Good. Thus, by making the lower end of the cooling gas discharge nozzle into a flange shape extending outward, the cooling gas discharged from the gas discharge port on the substrate flows along the gap space between the lower surface of the flange portion and the substrate surface. Thus, the substrate surface can be touched for a long time without dissipating the cooling gas. Further, the flow rate of the gas can be increased by flowing the cooling gas through the narrow gap space. Accordingly, the heat transfer rate from the cooling gas to the liquid film on the substrate can be increased, and the substrate and the liquid film can be efficiently cooled to a low temperature in a shorter time.

  At this time, since the flange portion is cooled in advance by keeping the nozzle facing surface of the rectifying member facing the lower surface of the flange portion while the cooling gas discharge nozzle is in the retracted position, the cooling gas discharge nozzle is disposed on the substrate. As a result, the liquid film on the substrate can be immediately cooled.

  According to the present invention, the cooling gas is discharged from the gas discharge port of the cooling gas discharge nozzle in the retracted position, and the rectifying member is disposed in close proximity to and below the gas discharge port, thereby changing the direction of the airflow from the gas discharge port. It can be controlled in the direction toward the outside. Since the flow straightening member is disposed below the gas discharge port, the ambient atmosphere is prevented from entering the nozzle from around and below the gas discharge port. Contamination can be reliably prevented.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the substrate processing apparatus concerning this invention. It is a block diagram which shows the control structure of the substrate processing apparatus of FIG. It is a figure which shows the detailed structure of a cooling gas nozzle and a rectification | straightening member. It is a flowchart which shows the aspect of the freeze washing process in this embodiment. It is a figure which shows typically the operation | movement in the process of FIG. It is a timing chart which shows operation | movement of each part of an apparatus in this freezing washing process. It is a figure which shows the principal part of 2nd Embodiment of the substrate processing apparatus concerning this invention.

<First Embodiment>
FIG. 1 is a diagram showing a first embodiment of a substrate processing apparatus according to the present invention. FIG. 2 is a block diagram showing a control configuration of the substrate processing apparatus of FIG. This substrate processing apparatus is a substrate processing apparatus as a single wafer cleaning apparatus capable of executing a substrate cleaning process for removing contaminants such as particles adhering to the surface Wf of a substrate W such as a semiconductor wafer. .

  The substrate processing apparatus includes a processing chamber 1 having a processing space for cleaning the substrate W therein, and the substrate W is placed in the processing space SP in the processing chamber 1 with the substrate surface Wf facing upward. A spin chuck 2 that rotates while being held in a substantially horizontal posture, a cooling gas nozzle 3 that discharges a cooling gas for cooling and freezing the liquid film toward the surface Wf of the substrate W held on the spin chuck 2, and a substrate A two-fluid nozzle 5 for supplying droplets of the processing liquid to the surface Wf, a chemical liquid discharge nozzle 6 for discharging a chemical liquid toward the surface Wf of the substrate W held on the spin chuck 2, and a substrate held on the spin chuck 2 A blocking member 9 disposed opposite to the surface Wf of W is provided. As the treatment liquid, a chemical liquid or a cleaning liquid such as pure water or DIW (deionized water) is used.

  The spin chuck 2 has a rotation support shaft 21 connected to a rotation shaft of a chuck rotation mechanism 22 including a motor, and can rotate around a rotation center A0 by driving the chuck rotation mechanism 22. A disc-shaped spin base 23 is integrally connected to the upper end portion of the rotation spindle 21 by a fastening component such as a screw. Therefore, the spin base 23 rotates around the rotation center A0 by driving the chuck rotation mechanism 22 in accordance with an operation command from the control unit 4 (FIG. 2) that controls the entire apparatus.

  Near the periphery of the spin base 23, a plurality of chuck pins 24 for holding the periphery of the substrate W are provided upright. Three or more chuck pins 24 may be provided to securely hold the circular substrate W, and are arranged at equiangular intervals along the peripheral edge of the spin base 23. Each of the chuck pins 24 includes a substrate support portion that supports the peripheral portion of the substrate W from below, and a substrate holding portion that holds the substrate W by pressing the outer peripheral end surface of the substrate W supported by the substrate support portion. Yes. Each chuck pin 24 is configured to be switchable between a pressing state in which the substrate holding portion presses the outer peripheral end surface of the substrate W and a released state in which the substrate holding portion is separated from the outer peripheral end surface of the substrate W.

  When the substrate W is delivered to the spin base 23, the plurality of chuck pins 24 are released, and when the substrate W is cleaned, the plurality of chuck pins 24 are pressed. State. By setting the pressed state, the plurality of chuck pins 24 can grip the peripheral edge of the substrate W and hold the substrate W in a substantially horizontal posture at a predetermined interval from the spin base 23. As a result, the substrate W is held with the front surface (pattern forming surface) Wf facing upward and the back surface Wb facing downward.

  A first rotation motor 31 is provided outside the spin chuck 2. A first rotation shaft 33 is connected to the first rotation motor 31. A first arm 35 is connected to the first rotating shaft 33 so as to extend in the horizontal direction, and the cooling gas nozzle 3 is attached to the tip of the first arm 35. Then, the first rotation motor 31 is driven according to the operation command from the control unit 4, so that the first arm 35 can be swung around the first rotation shaft 33.

  The cooling gas nozzle 3 is connected to a gas supply unit 64 (FIG. 2), and the cooling gas is supplied from the gas supply unit 64 to the cooling gas nozzle 3 in accordance with an operation command from the control unit 4. More specifically, the nitrogen gas supplied from the nitrogen gas storage unit 641 provided in the gas supply unit 64 is cooled to a temperature lower than the freezing point of DIW by the heat exchanger 642. The nitrogen gas thus cooled is supplied as the cooling gas to the cooling gas nozzle 3 along the supply path 643 disposed from the heat exchanger 642 to the cooling gas nozzle 3 through the first arm 35. When the cooling gas nozzle 3 is disposed to face the substrate surface Wf, the cooling gas is locally discharged from the discharge port 30 provided on the lower surface of the cooling gas nozzle 3 toward the substrate surface Wf. While the cooling gas is discharged from the cooling gas nozzle 3, the control unit 4 moves the cooling gas nozzle 3 from the rotation center of the substrate toward the outer peripheral portion while rotating the substrate W, so that the cooling gas is removed from the substrate surface Wf. Can be supplied over the entire surface. At this time, if a liquid film made of DIW is formed in advance on the substrate surface Wf as described later, it is possible to freeze the entire liquid film and generate a frozen film of DIW on the entire surface of the substrate surface Wf.

  The first rotation motor 31 can position the cooling gas nozzle 3 at a retracted position set outside the upper side of the substrate W, as indicated by a dotted line in FIG. Immediately below the cooling gas nozzle 3 positioned at the retracted position, a rectifying member 37 whose upper surface is a horizontal plane is provided. The structures and functions of the cooling gas nozzle 3 and the rectifying member 37 will be described in detail later.

  A second rotation motor 51 is provided outside the spin chuck 2. A second rotation shaft 53 is connected to the second rotation motor 51, and a second arm 55 is connected to the second rotation shaft 53. A two-fluid nozzle 5 is attached to the tip of the second arm 55. The two-fluid nozzle 5 can be swung around the second rotation shaft 53 by driving the second rotation motor 51 in accordance with an operation command from the control unit 4. This two-fluid nozzle is a so-called external mixing type two-fluid nozzle that generates DIW droplets by colliding DIW as a processing liquid and nitrogen gas in the air (outside the nozzle).

  A third rotation motor 67 is provided outside the spin chuck 2. A third rotation shaft 68 is connected to the third rotation motor 67. A third arm 69 is connected to the third rotation shaft 68 so as to extend in the horizontal direction, and a chemical liquid discharge nozzle 6 is attached to the tip of the third arm 69. Then, the third rotation motor 67 is driven in accordance with an operation command from the control unit 4 so that the chemical solution discharge nozzle 6 is retracted laterally from the discharge position and the discharge position above the rotation center A0 of the substrate W. It is possible to reciprocate between the standby position. The chemical solution discharge nozzle 6 is connected to the chemical solution supply unit 61, and a chemical solution such as an SC1 solution (mixed aqueous solution of ammonia water and hydrogen peroxide solution) is pumped to the chemical solution discharge nozzle 6 in accordance with an operation command from the control unit 4. Is done.

  The cooling gas nozzle 3, the two-fluid nozzle 5, the chemical solution discharge nozzle 6, and the arm associated therewith and the rotation mechanism thereof are, for example, those described in Patent Document 1 (Japanese Patent Laid-Open No. 2008-071875) described above. The thing of the same structure can be used. Therefore, in this specification, a more detailed description of these configurations is omitted.

  A disc-shaped blocking member 9 having an opening at the center is provided above the spin chuck 2. The blocking member 9 has a lower surface (bottom surface) that faces the substrate surface Wf and is substantially parallel to the substrate surface Wf. The planar size of the blocking member 9 is equal to or greater than the diameter of the substrate W. The blocking member 9 is attached substantially horizontally to a lower end portion of a support shaft 91 having a substantially cylindrical shape, and the support shaft 91 is rotatably held around a vertical axis passing through the center of the substrate W by an arm 92 extending in the horizontal direction. . The arm 92 is connected to a blocking member rotating mechanism 93 and a blocking member lifting mechanism 94.

  The blocking member rotating mechanism 93 rotates the support shaft 91 around the vertical axis passing through the center of the substrate W in accordance with an operation command from the control unit 4. The blocking member rotating mechanism 93 is configured to rotate the blocking member 9 in the same rotational direction as the substrate W and at substantially the same rotational speed in accordance with the rotation of the substrate W held by the spin chuck 2.

  Further, the blocking member elevating mechanism 94 can cause the blocking member 9 to face the spin base 23 in the vicinity of the spin base 23 according to an operation command from the control unit 4, or to separate the blocking member 9. Specifically, the control unit 4 operates the blocking member elevating mechanism 94 so that when the substrate W is carried into and out of the substrate processing apparatus, the separation position above the spin chuck 2 (the position shown in FIG. 1). ) To raise the blocking member 9. On the other hand, when a predetermined process is performed on the substrate W, the blocking member 9 is lowered to a facing position set very close to the surface Wf of the substrate W held by the spin chuck 2.

  The support shaft 91 is finished in a hollow shape, and a gas supply path 95 communicating with the opening of the blocking member 9 is inserted into the support shaft 91. The gas supply path 95 is connected to the gas supply unit 64, and nitrogen gas supplied from the nitrogen gas storage unit 641 without passing through the heat exchanger is supplied as a dry gas. In this embodiment, nitrogen gas is supplied from the gas supply path 95 to the space formed between the blocking member 9 and the substrate surface Wf during the drying process after the cleaning process for the substrate W. A liquid supply pipe 96 communicating with the opening of the blocking member 9 is inserted into the gas supply path 95, and a nozzle 97 is coupled to the lower end of the liquid supply pipe 96. An appropriate processing liquid is passed through the liquid supply pipe 96 to supply the processing liquid to the surface Wf of the substrate W.

  The DIW supply unit 62 includes a DIW storage unit 621, and the heat exchanger 622 cools the DIW supplied from the DIW storage unit 621 to a temperature near the freezing point thereof. That is, the DIW supply unit 62 can supply normal temperature DIW supplied from the DIW storage unit 621 or low-temperature DIW cooled to a temperature near the freezing point by the heat exchanger 622.

  The rotation support shaft 21 of the spin chuck 2 is a hollow shaft. A processing liquid supply pipe 25 for supplying a processing liquid to the back surface Wb of the substrate W is inserted into the rotary spindle 21. A gap between the inner wall surface of the rotation spindle 21 and the outer wall surface of the processing liquid supply pipe 25 forms a cylindrical gas supply path 29. The processing liquid supply pipe 25 and the gas supply path 29 extend to a position close to the lower surface (back surface Wb) of the substrate W held by the spin chuck 2, and the front end of the processing liquid supply tube 25 and the gas supply path 29 are processed toward the lower surface central portion of the substrate W. A lower surface nozzle 27 for discharging liquid and gas is provided.

  The treatment liquid supply pipe 25 is connected to the chemical liquid supply part 61 and the DIW supply part 62, and various liquids such as a chemical liquid such as an SC1 solution supplied from the chemical liquid supply part 61 or DIW supplied from the DIW supply part 62 are provided. Selectively supplied. On the other hand, the gas supply path 29 is connected to the gas supply unit 64 and can supply nitrogen gas from the gas supply unit 64 to a space formed between the spin base 23 and the substrate back surface Wb.

  Further, a splash guard 20 is provided so as to surround the periphery of the spin chuck 2, and receives the processing liquid scattered from the rotating substrate by the rotation of the spin base 23 and guides it to a drainage recovery unit (not shown).

  FIG. 3 is a diagram showing a detailed structure of the cooling gas nozzle and the rectifying member. More specifically, FIG. 3A is a view showing the appearance and arrangement of the cooling gas nozzle 3 and the rectifying member 37 in the retracted position, and FIG. 3B is a cross-sectional view showing the internal structure of the cooling gas nozzle 3. is there. FIG. 3C is a view of the cooling gas nozzle 3 and the rectifying member 37 in the retracted position as viewed from below, and FIG. 3D is a cross-sectional view showing a configuration without a rectifying member as a comparative example. is there.

  As shown in FIGS. 3 (a) and 3 (b), the inside of the nozzle housing 301 and the first arm 35 of the cooling gas nozzle 3 is hollow, and the cylindrical hollow portion passes the cooling gas. It functions as a gas supply path 643 to be made. In the lower part of the nozzle housing 301, the gas supply path 643 has an enlarged diameter, and a buffer space 304 is formed in the nozzle housing 301 to reduce the flow rate of the cooling gas that has been sent. A gas discharge port 30 opens downward on the lower surface of the nozzle housing 301 and communicates with the buffer space 304.

  The cooling gas sent from the first arm 35 to the cooling gas nozzle 3 is discharged from the gas discharge port 30 at the lower end of the nozzle housing 301. As will be described in detail later, in the state where the cooling gas nozzle 3 is disposed on the upper part of the substrate, the discharged cooling gas is supplied toward the liquid film on the surface of the substrate. At this time, the cooling gas is once guided to the buffer space 304, thereby avoiding the problem that the cooling gas is jetted vigorously to blow off the liquid film formed on the substrate surface Wf.

  On the other hand, at the retracted position deviated from the upper side to the side of the substrate, as shown in FIG. 3B, an upper surface (nozzle facing surface) is provided directly below the gas discharge port 30 so as to cover the opening of the gas discharge port 30 from below. A rectifying member 37 having a flat surface 37a is disposed in proximity. As shown in FIG. 3 (c), the rectifying member 37 is made larger than the plane size of the opening of the gas discharge port 30, and covers the entire opening in the horizontal direction and is minute in the vertical direction. It arrange | positions directly under the gas discharge port 30 with a clearance gap.

  Even in the retracted position, a predetermined amount of cooling gas is discharged from the gas discharge port 30 for idling, suppressing a rise in the temperature in the supply path 643 and the nozzle when not in use, and promptly supplying low-temperature cooling gas when necessary. It can be discharged. At this time, as indicated by a solid arrow in FIG. 3B, the cooling gas discharged downward from the gas discharge port 30 strikes the nozzle facing surface 37 a of the rectifying member 37 and changes its direction, and the nozzle lower end and the nozzle facing surface are changed. It flows to the outside through a slit-like gap formed by 37a. By reducing the opening area of the gap, the flow rate of the gas increases, and the gas blows out from the gap more vigorously.

  The atmosphere in the processing chamber 1 in which the processing liquid is used is high humidity, and the atmosphere around the cooling gas nozzle 3 contains a lot of water vapor and mist formed by condensation thereof, as schematically indicated by the symbol V. When such steam V or the like enters the nozzle, it may be frozen by touching the cooling gas or by touching the inner wall of the nozzle cooled by the cooling gas to adhere to the nozzle. Such frost may fall on the substrate when the cooling gas nozzle 3 is moved onto the substrate W. In particular, when the frost contains contaminants such as particles, the substrate is contaminated.

  As described above, in this embodiment, the cooling gas is discharged in a state where the rectifying member 37 is disposed close to the gas discharge port 30 of the cooling gas nozzle 3 in the retracted position. As a result, an air flow that blows outward from the gap between the gas discharge port 30 and the rectifying member 37 is formed, so that the ambient atmosphere with high humidity is prevented from entering the nozzle and generating frost.

  On the other hand, in the comparative example shown in FIG. 3D in which the rectifying member is not provided, when the specific gravity of the discharged cooling gas is large, downflow occurs, and when the cooling gas is released into the free space and mixed with the surrounding atmosphere. As shown by the broken line arrows in the drawing, the ambient atmosphere containing water vapor or the like V enters the nozzle from the side of the gas discharge port 30 and generates frost in the nozzle as described above. May cause serious problems. When the cooling gas is stopped at the retreat position, a similar problem may occur because a downflow occurs due to the ambient atmosphere cooled around the nozzle. Such a problem is avoided in the configuration of the present embodiment.

  In order for the cooling gas discharged downward from the gas discharge port 30 to change its direction by the rectifying member 37 and to flow radially isotropic along the upper surface of the rectifying member 37, the opening of the gas discharge port 30 is used. The plane including the surface and the plane including the upper surface of the rectifying member 37 (nozzle facing surface 37a) are preferably horizontal planes.

  In the substrate processing apparatus configured as described above, the substrate W carried into the processing space SP in the processing chamber 1 is held by the spin chuck 2, and a predetermined chemical processing is performed as necessary. In addition, after the liquid film is formed on the surface Wf of the substrate W and frozen, the substrate W is subjected to a freeze cleaning process for removing adhering substances together with the frozen film. Since the basic principle of the freeze cleaning process in the apparatus having the above-described configuration is described in Patent Document 1 (Japanese Patent Laid-Open No. 2008-071875), detailed description thereof is omitted.

  FIG. 4 is a flowchart showing an aspect of the freeze cleaning process in this embodiment. FIG. 5 is a diagram schematically showing the operation in the process of FIG. In this apparatus, when an unprocessed substrate W is carried into the apparatus, the control unit 4 controls each part of the apparatus to execute a series of cleaning processes on the substrate W. Here, it is assumed that the substrate W is previously carried into the processing chamber 1 with the surface Wf facing upward and is held by the spin chuck 2, and the blocking member 9 is disposed in close proximity to the upper surface of the substrate. .

  At this time, idling is performed by discharging a small amount of cooling gas in advance from the cooling gas nozzle 3 positioned at the retracted position (step S101). Thereby, the temperature rise of the gas supply path in a standby state can be minimized. Since the cooling gas during idling aims to maintain the temperature of the supply path, the temperature of the gas discharged from the discharge port at this time does not necessarily need to be lower than the freezing point of the liquid constituting the liquid film. Further, in this embodiment, since the flow of the ambient atmosphere into the nozzle is suppressed by arranging the rectifying member 37 close to the cooling gas nozzle 3 at the retracted position, the gas flow rate is relatively small, and the gas in the entire process The amount used can be reduced.

  Subsequently, the control unit 4 drives the chuck rotating mechanism 22 to rotate the spin chuck 2 and supplies room temperature DIW from the nozzle 97 to the substrate surface Wf. Centrifugal force accompanying the rotation of the substrate W acts on the DIW supplied to the substrate surface, and the substrate is uniformly spread outward in the radial direction of the substrate W, and a part of the DIW is shaken off the substrate. Thus, the thickness of the liquid film is uniformly controlled over the entire surface of the substrate surface Wf, and a liquid film (water film) having a predetermined thickness is formed on the entire surface of the substrate Wf (step S102). When forming the liquid film, it is not an essential requirement to shake off part of the DIW supplied to the substrate surface Wf as described above. For example, the liquid film may be formed on the substrate surface Wf without shaking the DIW from the substrate W with the rotation of the substrate W stopped or with the substrate W rotated at a relatively low speed.

  When the liquid film formation is completed, the control unit 4 retracts the blocking member 9 to the separated position. In this state, as shown in FIG. 5A, a paddle-like liquid film LP having a predetermined thickness is formed on the surface Wf of the substrate W. Here, the paddle-like liquid film LP may be formed by, for example, the SC1 liquid supplied from the chemical liquid discharge nozzle 6. As described above, at this time, the cooling gas nozzle 3 is idling at the retracted position (position shown in FIG. 5A) spaced from the upper side of the substrate to the side, and a small amount of cooling gas discharged from the discharge port 30 is rectified. It flows from the gap with the member 37 to the side.

  Subsequently, the cooling gas nozzle 3 is moved from the retracted position to above the rotation center AO of the substrate (step S103). Then, as shown in FIG. 5B, the cooling gas nozzle 3 is gradually moved toward the edge W of the substrate W while discharging a larger amount of cooling gas from the cooling gas nozzle 3 toward the surface Wf of the rotating substrate W than when idling. The scan is moved toward the position (step S104).

  Thereby, the liquid film LP formed in the surface region of the substrate surface Wf is cooled and partially frozen, and the frozen region (frozen region FR) is the center of the substrate surface Wf as shown in FIG. Formed in the part. Then, the frozen region FR is expanded from the central portion to the peripheral portion of the substrate surface Wf by the scanning of the nozzle 3 in the direction Dn1, and finally, as shown in FIG. 5D, the entire surface of the liquid film on the substrate surface Wf. Freezes. When the entire liquid film is frozen, the cooling gas nozzle 3 is retracted to the retracted position. At this time, the cooling gas discharge amount from the cooling gas nozzle 3 is reduced to return to the idling state (step S105).

  Here, as the cooling gas supplied to the substrate, for example, nitrogen gas of −150 ° C. and 50 L / min can be used. Moreover, as target temperature of the liquid film after freezing, it can be set to -30 degreeC, for example. When the scan of the cooling gas is completed, the blocking member 9 is again placed close to the substrate surface Wf (step S106), and the DIW at room temperature is directed from the nozzle 97 provided on the blocking member 9 toward the frozen liquid film on the substrate surface Wf. Is supplied for rinsing (step S107).

  At the time when the processes so far are executed, DIW is supplied to the surface of the substrate W in a state where the substrate W rotates while being sandwiched between the blocking member 9 and the spin base 23. Here, instead of supplying room temperature DIW to the substrate surface Wf, a droplet of DIW may be supplied from the two-fluid nozzle 5. Subsequently, the supply of DIW to the substrate is stopped, and a spin drying process for drying the substrate by high-speed rotation is performed (step S108). That is, by rotating the substrate W at a high speed while discharging nitrogen gas from the nozzle 97 provided on the blocking member 9 and the lower surface nozzle 27 provided on the spin base 23, the DIW remaining on the substrate W is shaken off. Dry. The nitrogen gas supplied at this time acts as a dry gas, and is a normal temperature gas that does not pass through a heat exchanger. When the drying process is completed in this manner, the processed substrate W is carried out to complete the process for one substrate.

  The cleaning effect obtained by the above treatment will be described. When the liquid film is frozen as described above, the volume of the liquid film entering between the substrate surface Wf and the particles increases (when water at 0 ° C. becomes ice at 0 ° C., the volume is about 1.1. The particles are separated from the substrate surface Wf by a minute distance. As a result, the adhesion force between the substrate surface Wf and the particles is reduced, and further, the particles are detached from the substrate surface Wf. At this time, even if a fine pattern is formed on the substrate surface Wf, the pressure applied to the pattern by the volume expansion of the liquid film is equal in all directions, that is, the force applied to the pattern is canceled out. Therefore, it is possible to peel only the particles from the substrate surface Wf while preventing the pattern from peeling or collapsing. Then, by removing the liquid film frozen by newly supplied DIW, particles and the like can also be removed from the substrate surface Wf.

  FIG. 6 is a timing chart showing the operation of each part of the apparatus in this freeze cleaning process. At the beginning of the process, the cooling gas nozzle 3 discharges the cooling gas at a flow rate low enough to maintain the supply path 643 at a low temperature, and the position is a retreat position. The low flow rate cooling gas discharged from the cooling gas nozzle 3 is discharged to the processing space SP from the gap between the gas discharge port 30 and the rectifying member 37. In the period indicated by the symbol A in FIG. 6 in which this state is maintained, the substrate W is loaded from the outside and held on the spin base 23.

  In a subsequent period B from time T1 to T2, a liquid film is formed on the substrate surface Wf. At this time, the flow rate of the cooling gas from the cooling gas nozzle 3 is increased. By increasing the flow rate of the cooling gas, it is possible to discharge the cooling gas that is maintained at a sufficiently low temperature in the subsequent scanning operation.

  The movement of the cooling gas nozzle 3 is started at time T2, and the cooling gas nozzle 3 is transferred from the retracted position to above the rotation center AO of the substrate W in a period C up to time T3. Then, the cooling gas nozzle 3 is scanned from the center of the substrate toward the periphery (period D). When the cooling gas nozzle 3 reaches above the periphery of the substrate at time T4, the flow rate of the cooling gas is again lowered, and the cooling gas nozzle 3 is returned to the retracted position (period E). Further, during this period, the blocking member 9 is lowered to the board proximity position.

  The rinsing process is performed in a period F from time T5 when nozzle movement ends to the subsequent T6, and the spin drying process is performed in period G until time T7. In the subsequent period H, the processed substrate is unloaded. During these periods, a small amount of the cooling gas is discharged from the cooling gas nozzle 3 positioned at the retracted position to be in an idling state, whereby the temperature increase in the gas supply path can be suppressed.

  In order to increase the flow rate of the gas blown from the gap between the gas discharge port 30 and the nozzle facing surface 37a of the rectifying member 37, the opening area of the slit-like gap that communicates the inside of the nozzle and the free space is reduced. It is desirable. In the present embodiment, the opening area can be defined as the circumference of the gas discharge port 30 multiplied by the interval between the gas discharge port 30 and the surface facing the gas discharge port 30.

  For example, the gas discharge at the retreat position is larger than the opening area of the gap between the gas discharge port 30 and the substrate surface Wf (more precisely, the surface of the liquid film LP thereon) in a state where the cooling gas nozzle 3 is disposed on the substrate. If the opening area of the gap between the outlet 30 and the rectifying member 37 is made smaller, the gas flow rate required to obtain the same gas flow rate is smaller in the standby state. Thereby, the gas consumption as the whole apparatus can be suppressed.

  More specifically, the distance between the lower end of the cooling gas nozzle 3 and the upper surface of the rectifying member 37 indicated by reference numeral G1 in FIG. 5A is the lower end of the cooling gas nozzle 3 on the substrate and the liquid indicated by reference numeral G2 in FIG. The distance between the upper surface of the film LP and the film LP should be smaller.

  As described above, in this embodiment, by performing idling for discharging a predetermined amount of cooling gas from the gas discharge port 30 of the cooling gas nozzle 3 positioned at the retracted position, the cooling gas nozzle 3 and the gas supply path 643 in the standby state are set. Temperature rise is suppressed. Thereby, the sufficiently cooled cooling gas can be immediately discharged from the cooling gas nozzle 3 moved onto the substrate W, and the liquid film LP on the substrate can be frozen in a short time.

  At this time, instead of simply discharging the gas from the gas discharge port 30 into the processing space SP, the rectifying member 37 is disposed close to the gas discharge port 30, and from the gap between the gas discharge port 30 and the rectifying member 37 to the side. Creates an air current that blows out. By doing so, even if the gas flow rate is low, it is possible to effectively prevent the ambient atmosphere of high humidity from entering the nozzle, and it is possible to prevent frost from being generated in the nozzle. Thereby, it is possible to prevent the contamination of the substrate due to the fall of frost on the substrate.

  As described above, in this embodiment, the spin chuck 2 functions as the “substrate holding unit” of the present invention, and the cooling gas nozzle 3 functions as the “cooling gas discharge nozzle” of the present invention. Of these, the discharge port 30 corresponds to the “gas discharge port” of the present invention. Further, the rectifying member 37 functions as a “rectifying member” of the present invention. In this embodiment, the first rotation motor 31 that rotates the arm 35 on which the cooling gas nozzle 3 is mounted functions as the “moving means” of the present invention.

Second Embodiment
FIG. 7 is a view showing a main part of a second embodiment of the substrate processing apparatus according to the present invention. More specifically, FIG. 7A is a view showing the appearance of the cooling gas nozzle 32 of the second embodiment, and FIG. 7B is a longitudinal sectional view showing the internal structure thereof. Since the basic configuration of the substrate processing apparatus according to this embodiment is the same as that of the first embodiment, the differences will be mainly described here. Moreover, the same code | symbol is attached | subjected to the structure same as 1st Embodiment, and description is abbreviate | omitted. As shown in these drawings, in this embodiment, the outer peripheral portion of the nozzle housing 321 of the cooling gas nozzle 32 has a flat bottom flange 322 that functions as a substrate facing portion, with its lower end portion greatly extended outward. ing. The gas discharge port 320 is opened substantially at the center of the flange lower surface 322a.

  Also in this embodiment, the rectifying member 38 is disposed below the cooling gas nozzle 32 in the retracted position, and idling is performed. The rectifying member 38 has a larger planar size than the flange 322 of the cooling gas nozzle 32, and is disposed in close proximity to the cooling gas nozzle 32 so as to cover substantially the entire lower surface 322a of the flange 322 from below.

  Therefore, as indicated by a dotted arrow in FIG. 7B, the cooling gas fed from the arm 35 supporting the cooling gas nozzle 32 through the gas supply path 643 provided in communication with the cooling gas nozzle 32 is a gas discharge port. After being discharged from 320, it is discharged to the outside through a gap space between the flange lower surface 322a and the upper surface 38a of the rectifying member 38. According to such a configuration, as in the first embodiment, it is possible to prevent the generation of frost caused by a high humidity ambient atmosphere entering the nozzle, and to prevent contamination of the substrate due to the frost. .

  Here, from the viewpoint of simply preventing the ambient atmosphere from entering the nozzle, the rectifying member 38 may be provided so as to be larger than the gas discharge port 320 and cover the gas discharge port 320. On the other hand, in this embodiment, the rectifying member 38 is larger and is formed to be equal to or larger than the flange 322 at the lower end of the cooling gas nozzle 32 so as to cover the entire flange lower surface 322a. Therefore, at the time of idling, the cooling gas discharged from the gas discharge port 320 flows toward the outside while cooling it by touching the flange lower surface 322a.

  On the other hand, when the cooling gas nozzle 32 is disposed above the substrate W, the lower surface 322a of the flange 322 becomes a substrate facing surface that is in close proximity to the substrate surface held by the spin chuck 2. The cooling gas discharged from the gas discharge port 320 circulates along the substrate surface through a gap space sandwiched between the substrate facing surface 322a and the substrate surface (more precisely, the surface of the liquid film formed on the substrate surface). It will be. For this reason, the discharged cooling gas comes into contact with the liquid film on the substrate for a relatively long time. In addition, since the substrate facing surface 322a and the substrate surface are close to each other, the flow velocity of the cooling gas flowing along the substrate surface is relatively high. Further, the external atmosphere having a temperature higher than that of the cooling gas is suppressed from entering the gap space, and the increase in the gas temperature due to the mixing of the cooling gas and the ambient atmosphere is suppressed.

  For these reasons, in the configuration of the present embodiment, the heat transfer rate from the cooling gas to the liquid film formed on the substrate surface becomes higher, and the substrate and the liquid film can be efficiently cooled in a shorter time. That is, if the flow rate and processing time of the cooling gas are the same, the substrate and the liquid film can be cooled to a lower temperature, and if the ultimate temperature of the substrate and liquid film is the same, the flow rate and the processing time of the cooling gas are reduced. Is possible.

  In this embodiment, the flange 322 is previously cooled by the cooling gas discharged from the gas discharge port 320 during idling. For this reason, it is suppressed that the heat of the cooling gas supplied to the gap space sandwiched between the substrate facing surface 322a of the flange 322 and the liquid film surface is taken away by the flange 322, and the substrate and the liquid film are removed by the cooling gas. It is possible to cool efficiently and in a short time.

  The size of the flange 322 is preferably larger from the viewpoint of the cooling efficiency of the liquid film, but the size of the processing chamber 1 and the entire apparatus is increased accordingly, so that the area of the surface area of the substrate is about ½, for example. It is preferable that For example, in a system for processing a substrate W having a diameter of 300 mm, one side of the flange 32 can be about 150 mm to 200 mm. In this embodiment, the cross-sectional shape of the supply path 643 and the opening shape of the gas discharge port 320 are rectangular, and accordingly the shape of the flange 322 is also rectangular, but these shapes are limited to rectangular shapes. For example, it may be a circle, an oval, or another polygon. Moreover, there is no problem even if these shapes are different from each other.

<Others>
The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above embodiment, the “liquid film” of the present invention is formed by DIW, but the liquid constituting the liquid film is not limited to this. For example, carbonated water, hydrogen water, dilute ammonia water (for example, about 1 ppm), dilute hydrochloric acid or the like, or DIW added with a small amount of surfactant may be used.

  In the above embodiment, idling is performed when the cooling gas nozzle is in the retracted position. However, in order to reduce the processing time, at least the liquid film on the substrate is to be cooled in advance. It is only necessary to perform idling for a certain period immediately before the start of freezing, and it is not essential to perform idling at all times.

  Moreover, in the said embodiment, although nitrogen gas made into temperature lower than the freezing point of the liquid (DIW) which comprises a liquid film is used as cooling gas, cooling gas is not limited to nitrogen gas. For example, a rare gas such as argon gas, other inert gas, dry air, or the like may be used.

  Further, the substrate processing apparatus of the above embodiment incorporates the DIW storage unit 621 and the nitrogen gas storage unit 641 inside the apparatus, but the processing liquid and the gas supply source may be provided outside the apparatus. For example, you may make it utilize the supply source of the existing process liquid and gas in a factory. Further, when there are existing facilities for cooling them, liquid or gas cooled by the facilities may be used.

  Moreover, although the substrate processing apparatus of the said embodiment has the shielding member 9 arrange | positioned close to the upper direction of the board | substrate W, this invention is applicable also to the apparatus which does not have a shielding member. In the apparatus of this embodiment, the substrate W is held by the chuck pins 24 that come into contact with the peripheral edge thereof. However, the substrate holding method is not limited to this, and the substrate is held by another method. The present invention can also be applied to an apparatus.

  The present invention relates to a semiconductor wafer, 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 can be applied to a substrate processing apparatus and a substrate processing method for freezing a liquid film formed on the entire surface of a substrate including the substrate.

2 Spin chuck (substrate holding means)
3,32 Cooling gas nozzle (cooling gas discharge nozzle)
30, 320 Gas outlet 31 First rotation motor (moving means)
37,38 Rectifying member W substrate

Claims (7)

Substrate holding means for holding the substrate having a liquid film formed on the surface thereof substantially horizontally;
A cooling gas discharge nozzle that discharges a cooling gas having a temperature lower than the freezing point of the liquid constituting the liquid film from a gas discharge port that opens downward;
The cooling gas discharge nozzle is scanned and moved along the surface of the substrate by moving the cooling gas discharge nozzle relative to the substrate held by the substrate holding means, and the cooling gas discharge nozzle is A moving means that can be positioned at a retracted position deviated from above the substrate;
A rectifying member that is disposed below the gas discharge port of the cooling gas discharge nozzle positioned at the retreat position, and whose upper surface is a nozzle facing surface larger than the opening of the gas discharge port,
With the cooling gas discharge nozzle positioned at the retracted position, a predetermined amount of the cooling gas is discharged from the gas discharge port, and the nozzle facing surface of the rectifying member faces the gas discharge port and is close to the gas discharge port. A substrate processing apparatus, wherein the substrate processing apparatus is arranged.   The gas discharge port of the cooling gas discharge nozzle and the substrate surface in which the interval between the gas discharge port of the cooling gas discharge nozzle positioned at the retracted position and the nozzle facing surface is scanned and moved with respect to the substrate surface. The substrate processing apparatus according to claim 1, wherein the substrate processing apparatus is smaller than an interval between the substrate processing apparatus and the substrate processing apparatus.   The area of the slit-shaped opening formed by the peripheral edge portion of the gas discharge port of the cooling gas discharge nozzle positioned at the retracted position and the nozzle facing surface is smaller than the opening area of the gas discharge port. 3. The substrate processing apparatus according to 1 or 2.   The discharge amount of the cooling gas from the gas discharge port in a state where the cooling gas discharge nozzle is positioned at the retracted position is scanned from the gas discharge port of the cooling gas discharge nozzle that is scanned and moved with respect to the substrate surface. The substrate processing apparatus according to claim 1, wherein the substrate processing apparatus is smaller than a discharge amount of the cooling gas.   The substrate processing apparatus according to claim 1, wherein an opening surface of the gas discharge port and the nozzle facing surface are both horizontal planes.   The lower end outer peripheral part of the said cooling gas discharge nozzle is extended outside, and becomes the flange part surrounding the said gas discharge port, The said nozzle opposing surface of the said rectification | straightening member is larger than the plane size of the said flange part. The substrate processing apparatus according to claim 5. Forming a liquid film on the surface of the substrate;
A step of moving a cooling gas discharge nozzle having a gas discharge port that opens downward from a retracted position off the upper side of the substrate to an upper side of the substrate on which the liquid film is formed;
The liquid film is solidified by supplying a cooling gas having a temperature lower than the freezing point of the liquid constituting the liquid film from the gas discharge port while relatively moving the cooling gas discharge nozzle along the substrate surface. A process of
Melting and removing the solidified solidified body of the liquid film,
Before moving the gas discharge nozzle above the substrate, while discharging the cooling gas from the gas discharge port, the nozzle of the rectifying member whose upper surface is a nozzle facing surface larger than the opening of the gas discharge port A substrate processing method characterized in that an opposing surface is arranged close to the gas discharge port of the cooling gas discharge nozzle in the retracted position.

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