JP4781253B2 - Substrate processing apparatus and substrate processing method - Google Patents

Description

  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), an optical disk substrate, a magnetic disk substrate, a magneto-optical disk substrate, etc. The present invention relates to a substrate processing apparatus and a substrate processing method suitable for a freezing process for freezing a liquid film formed on the surface of various substrates (hereinafter simply referred to as “substrate”).

  Conventionally, a technique of freezing a liquid film by cooling the substrate with the liquid film attached to the surface of the substrate is used as one of the processes for the substrate. In particular, such a freezing technique is used as part of a cleaning process for a substrate. In other words, fine contaminants such as particles adhering to the substrate surface without collapsing the pattern formed on the substrate surface with the miniaturization, higher functionality, and higher accuracy of devices typified by semiconductor devices. It has become increasingly difficult to remove. Therefore, the contaminants adhering to the substrate surface are removed using the above-described freezing technique as follows.

  First, a liquid is supplied to the substrate surface to form a liquid film on the substrate surface. Subsequently, the liquid film is frozen by cooling the substrate. As a result, a frozen film is formed on the surface of the substrate to which the contaminant is attached. Finally, by removing the frozen film from the substrate surface, contaminants are removed from the substrate surface together with the frozen film.

  Here, as a substrate processing method for freezing the liquid film formed on the substrate surface, there are the following methods. For example, in the apparatus described in Patent Document 1, a substrate is accommodated in a processing chamber, and the substrate is supported on a pedestal (pedestal). A removal fluid such as steam or ultrapure water vapor is supplied to the substrate surface. Thereby, a liquid film is formed by the removal fluid on the substrate surface. Subsequently, a cooling gas having a temperature lower than the freezing temperature of the removal fluid is injected into the processing chamber, and the cooling gas is circulated in the processing chamber. Then, the liquid film formed on the substrate surface is frozen.

JP-A-3-145130 (FIG. 1)

  By the way, in the apparatus described in Patent Document 1, a cooling gas is injected into the processing chamber and the cooling gas is circulated in the processing chamber to freeze the liquid film formed on the substrate surface. For this reason, not only the substrate but also a peripheral member located around the substrate including the substrate holding means such as a pedestal (hereinafter simply referred to as “substrate peripheral member”) is cooled to a temperature below or near the freezing temperature by the cooling gas. It will be cooled. As a result, there has been a problem that the peripheral member of the substrate is damaged by cold and the durability of the peripheral member of the substrate is deteriorated.

  Therefore, it is conceivable to supply the cooling gas directly to the liquid film formed on the substrate surface instead of circulating the cooling gas in the processing chamber. That is, it is conceivable to dispose the nozzle above the substrate surface and move the nozzle relative to the substrate along the substrate surface while discharging the cooling gas from the nozzle. Thereby, while the liquid film formed on the substrate surface is locally frozen, a region (frozen region) where the liquid film is frozen is expanded in the surface region of the substrate surface, and the entire liquid film is frozen. For this reason, the supply site of the cooling gas can be limited to a partial region on the substrate surface, and the temperature drop of the substrate peripheral member can be minimized.

  However, when the cooling gas is discharged from the nozzle as described above to freeze the liquid film, it is necessary to consider the following points. That is, it is difficult to dispose the nozzle and the cooling gas supply source that supplies the cooling gas to the nozzle close to each other due to the configuration of the apparatus. For this reason, piping (gas introduction piping) for introducing the cooling gas from the cooling gas supply source into the nozzle is required, and the length of the piping is relatively long. As a result, until the cooling gas from the cooling gas supply source is introduced into the nozzle, the cooling gas absorbs heat from the external atmosphere via the pipe, and the temperature of the cooling gas rises. As a result, it may be difficult to freeze the liquid film.

  Therefore, in order to suppress heat absorption from the external atmosphere to the cooling gas, it is conceivable to increase the flow rate of the cooling gas supplied from the cooling gas supply source toward the nozzle. However, in this case, even if the temperature rise of the cooling gas can be suppressed, the following new problem may occur. That is, when the flow rate of the cooling gas is increased, the liquid film may be dried before the liquid film is frozen by the cooling gas discharged from the nozzle.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a substrate processing apparatus and a substrate processing method capable of reliably freezing a liquid film while preventing the liquid film from drying.

  The inventor of the present application, when discharging the cooling gas from the nozzle and freezing the liquid film, the flow passage cross-sectional area of the circulation space (hereinafter simply referred to as “distribution space”) in which the cooling gas circulates in the nozzle, It considered as follows regarding the flow-path cross-sectional area of the connected piping. That is, considering only that the cooling gas from the cooling gas supply source is introduced into the nozzle through the pipe and discharged from the nozzle, the flow path cross-sectional area of the pipe and the cross-sectional area of the circulation space have the same size. Can be set to However, when such a dimensional relationship is adopted, the flow rate of the cooling gas flowing through the piping and the flow rate of the cooling gas introduced from the piping into the distribution space and flowing through the distribution space are substantially the same. End up. For this reason, as described above, when the flow rate of the cooling gas flowing through the piping is increased in order to suppress the heat absorption from the external atmosphere to the cooling gas, the flow space is increased in such a state that the flow rate is increased. Cooling gas flows and is discharged from the nozzle. As a result, the liquid film may be dried.

  Therefore, the substrate processing apparatus and the substrate processing method according to the present application are configured as follows from the viewpoint of preventing the liquid film from drying.

The present invention is a substrate processing apparatus suitable for a freezing process for freezing a liquid film formed on a substrate surface, and in order to achieve the above object, a substrate that holds the substrate in a state in which the liquid film is formed on the substrate surface A holding gas, and a cooling gas discharge nozzle that has a flow space in which a cooling gas having a temperature lower than the freezing point of the liquid constituting the liquid film is circulated, and discharges the cooling gas in the flow space toward the liquid film; A gas introduction pipe connected to the cooling gas discharge nozzle for introducing the cooling gas into the circulation space, and a drive mechanism for moving the cooling gas discharge nozzle relative to the substrate surface along the substrate surface while facing the cooling gas , sectional area of circulation space in a plane perpendicular to the cooling gas flow discharged toward the substrate surface much larger than the flow path cross-sectional area of the gas introduction pipe, a cooling gas onto the substrate surface from the cooling gas discharge nozzle While only allowed locally discharged, the drive mechanism is a cooling gas discharge nozzle is characterized by relatively moving with respect to the substrate.

The present invention is also a substrate processing method suitable for a freezing process in which a liquid film formed on a substrate surface is frozen. In order to achieve the above object, the substrate is held in a state in which the liquid film is formed on the substrate surface. A substrate holding step, and a gas introduction pipe connected to the cooling gas discharge nozzle into a circulation space that is provided inside the cooling gas discharge nozzle and distributes the cooling gas having a temperature lower than the freezing point of the liquid constituting the liquid film. The gas introduction step for introducing the cooling gas and the cooling gas introduced into the distribution space are discharged toward the liquid film from the cooling gas discharge nozzle spaced from and opposed to the substrate surface while the cooling gas discharge nozzle is placed on the substrate surface. along a gas discharge process to Ru is relative movement, than the flow path cross-sectional area of the cross-sectional area is the gas inlet pipe of the circulation space in a plane perpendicular to respect the cooling gas flow discharged toward the substrate surface It is characterized in that heard.

In the invention (substrate processing apparatus and substrate processing method) configured as described above, in a plane orthogonal to the cooling gas flow discharged toward the substrate surface from the gas introduction pipe having a relatively small channel cross-sectional area. Cooling gas is introduced into the flow space inside the nozzle having a relatively large cross-sectional area. As a result, the cooling gas introduced into the circulation space from the gas introduction pipe spreads in the circulation space and is discharged from the cooling gas discharge nozzle. For this reason, the flow rate of the cooling gas introduced into the flow space and flowing through the flow space is smaller than the flow rate of the cooling gas flowing through the gas introduction pipe. That is, the flow rate of the cooling gas can be decelerated inside the nozzle. As a result, the flow rate of the cooling gas can be reduced inside the nozzle even when the flow rate of the cooling gas flowing through the inside of the gas introduction pipe is increased to suppress heat absorption from the external atmosphere to the cooling gas. it can. Therefore, by moving the cooling gas discharge nozzle relative to the substrate surface while discharging the cooling gas, the liquid film can be reliably frozen while preventing the liquid film from drying.

  Here, the distribution space further includes a plate-like member disposed so that the surface thereof is opposed to the opening portion opened at the connection position of the cooling gas discharge nozzle and the gas introduction piping, and the gas introduction piping is circulated from the opening portion. The cooling gas may be introduced into the space so that the cooling gas collides with the surface of the plate-like member and rectifies, and the cooling gas discharge nozzle may be configured to discharge the rectified cooling gas. According to this configuration, the flow rate of the cooling gas can be reduced in two stages inside the nozzle. That is, the cooling gas introduced into the distribution space from the opening spreads in the distribution space, and the flow rate of the cooling gas introduced into the distribution space is compared with the flow rate of the cooling gas flowing through the gas introduction pipe. Get smaller. Furthermore, the cooling gas introduced into the circulation space collides with the surface of the plate-like member arranged to face the opening of the gas introduction pipe and is rectified. For this reason, the flow rate of the cooling gas supplied toward the liquid film can be further reduced. Therefore, drying of the liquid film can be reliably prevented.

  Here, it is preferable to arrange the plate-like member so that the surface thereof is substantially parallel to a plane orthogonal to the cooling gas flow discharged toward the substrate surface. According to this configuration, the cooling gas introduced into the circulation space collides with the plate member, and is rectified in a direction orthogonal to the cooling gas flow discharged toward the substrate surface. For this reason, the flow velocity of the cooling gas discharged toward the substrate surface can be effectively reduced, which is effective in preventing the liquid film from drying.

  The gas introduction pipe is configured to introduce a cooling gas into the flow space and rectify the cooling gas by colliding with the inner wall surface of the cooling gas discharge nozzle, and the cooling gas discharge nozzle is configured to discharge the rectified cooling gas. Also good. According to this configuration, the cooling gas introduced into the circulation space spreads in the circulation space, so that the flow rate of the cooling gas is reduced. Further, the cooling gas introduced into the circulation space collides with the inner wall surface of the cooling gas discharge nozzle and is rectified. For this reason, the flow rate of the cooling gas supplied toward the liquid film can be further reduced, and the liquid film can be reliably prevented from drying. Further, according to this configuration, it is not necessary to additionally provide a member for rectifying the cooling gas introduced into the circulation space, so that the configuration of the apparatus can be simplified.

  Here, it is preferable that the gas introduction pipe introduces the cooling gas into the circulation space from a direction substantially parallel to the surface direction in the plane of the substrate surface. According to this configuration, the cooling gas introduced into the circulation space is incident on the inner wall surface from a direction substantially parallel to the surface direction in the surface of the substrate, collides with the inner wall surface, and is rectified. For this reason, it is possible to effectively reduce the flow rate of the cooling gas in the direction substantially orthogonal to the surface direction in the surface of the substrate surface, which is effective in preventing the drying of the liquid film.

Further, the entire liquid film may be frozen by moving the cooling gas discharge nozzle for discharging the cooling gas relative to the substrate. According to this configuration, the cooling gas discharge nozzle is moved relative to the substrate along the substrate surface while discharging the cooling gas, so that the liquid film is frozen in the surface region of the substrate surface (frozen region). Is spread and the entire liquid film is frozen. Moreover, according to the present invention, the cooling gas introduced into the circulation space from the gas introduction pipe spreads in the circulation space and is discharged from the cooling gas discharge nozzle. For this reason, compared with the case where cooling gas is discharged from the nozzle which has the opening (discharge port) of the same cross-sectional area as the flow-path cross-sectional area of gas introduction piping, the supply range of the cooling gas with respect to a liquid film is wide. Therefore, the entire liquid film can be frozen more quickly than in the case where the cross-sectional area of the nozzle opening is the same as the cross-sectional area of the gas introduction pipe. As a result, the throughput of the apparatus required for the liquid film freezing process can be improved.

  According to this invention, the gas whose cross-sectional area in a plane orthogonal to the cooling gas flow discharged toward the substrate surface of the circulation space provided inside the cooling gas discharge nozzle is connected to the cooling gas discharge nozzle. It is larger than the cross-sectional area of the introduction pipe. For this reason, the flow rate of the cooling gas introduced into the flow space and flowing through the flow space is smaller than the flow rate of the cooling gas flowing through the gas introduction pipe. As a result, the flow rate of the cooling gas can be reduced inside the nozzle even when the flow rate of the cooling gas flowing through the inside of the gas introduction pipe is increased to suppress heat absorption from the external atmosphere to the cooling gas. it can. Therefore, the liquid film can be reliably frozen while preventing the liquid film from drying.

<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 apparatus is a single-wafer type substrate processing apparatus used for a cleaning process for removing contaminants such as particles adhering to the surface Wf of a substrate W such as a semiconductor wafer. More specifically, after forming a liquid film on the substrate surface Wf on which the fine pattern is formed, freezing the liquid film and then removing the frozen liquid film (frozen film) from the substrate surface Wf, This is an apparatus for performing a series of cleaning processes (liquid film formation + liquid film freezing + film removal) on the substrate W.

  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 a substantially horizontal posture with the substrate surface Wf facing upward in the processing chamber 1. Cooling that discharges a cooling gas for freezing the liquid film toward the surface Wf of the substrate W held by the spin chuck 2 (corresponding to the “substrate holding means” of the present invention) that is held and rotated and the spin chuck 2 A gas discharge nozzle 3 and a blocking member 5 disposed to face the surface Wf of the substrate W held by the spin chuck 2 are provided.

  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 nozzle moving mechanism 31 is connected to the cooling gas discharge nozzle 3. Then, the nozzle moving mechanism 31 is actuated in accordance with an operation command from the control unit 4 so that the cooling gas discharge nozzle 3 swings around a predetermined rotation axis. Accordingly, the cooling gas discharge nozzle 3 can be moved along the substrate surface Wf while facing the substrate surface Wf.

  FIG. 3 is a view showing the operation of the cooling gas discharge nozzle provided in the substrate processing apparatus of FIG. Here, FIG. 4A is a side view and FIG. 4B is a plan view. When the nozzle moving mechanism 31 is actuated, the cooling gas discharge nozzle 3 faces the substrate surface Wf and moves from the movement locus T in FIG. 5B, that is, from the rotation center position Pc of the substrate W to the edge position Pe of the substrate W. It moves along the trajectory T. Here, the rotation center position Pc of the substrate W is set above the substrate surface Wf and on the rotation center A0 of the substrate W. Further, the cooling gas discharge nozzle 3 is movable to a standby position Ps retracted to the side of the substrate W. Thus, in this embodiment, the nozzle moving mechanism 31 functions as a “driving mechanism” that moves the cooling gas discharge nozzle 3 relative to the substrate W along the substrate surface Wf.

  The cooling gas discharge nozzle 3 is connected to a gas introduction pipe 33 and communicates with the cooling gas supply unit 15 (FIG. 2) via the gas introduction pipe 33. For this reason, when the cooling gas is pumped from the cooling gas supply unit 15 in accordance with the operation command from the control unit 4, the cooling gas is introduced from the gas introduction pipe 33 to the cooling gas discharge nozzle 3. As a result, the cooling gas is discharged from the cooling gas discharge nozzle 3. And according to the operation command from the control unit 4, when the cooling gas discharge nozzle 3 is disposed close to and opposed to the substrate surface Wf and the cooling gas is discharged from the cooling gas discharge nozzle 3, it is directed toward the substrate surface Wf. Cooling gas is supplied locally. Here, the distance between the substrate surface Wf and the cooling gas discharge nozzle 3 is set to, for example, 6 to 7 mm. Therefore, in the state where the cooling gas is discharged from the cooling gas discharge nozzle 3, the control unit 4 moves the cooling gas discharge nozzle 3 along the movement trajectory T while rotating the substrate W. It can be supplied over the entire surface of Wf. Thus, as described later, when the liquid film 11f is formed on the substrate surface Wf, the entire liquid film 11f can be frozen to form the frozen film 13f on the entire surface of the substrate surface Wf.

  The cooling gas supply unit 15 adjusts the temperature of the cooling gas, for example, by cooling it with a cooling source such as liquid nitrogen. Such a cooling gas supply unit 15 is difficult to arrange in the vicinity of the cooling gas discharge nozzle 3 due to the configuration of the apparatus, so that the gas introduction pipe 33 has a relatively long length (pipe length). Needed. As the gas introduction pipe 33, for example, one having an inner diameter of φ10 mm is used.

  As the cooling gas, a gas adjusted to a temperature lower than the freezing point of the liquid constituting the liquid film 11 formed on the substrate surface Wf, such as nitrogen gas, oxygen gas, and clean air, can be used. In this embodiment, since the liquid film 11 formed on the substrate surface Wf is composed of DIW (deionized water) as described later, the temperature of the cooling gas is adjusted to a temperature lower than the freezing point (freezing point) of DIW. be able to. Further, when the cooling gas is used as described above, the following effects can be obtained. That is, when gas is used as the refrigerant, contaminants contained in the cooling gas can be easily and efficiently removed by inserting a filter or the like before supplying the gas to the substrate surface Wf. By using the cooling gas thus cleaned, it is possible to reliably prevent the contaminants from adhering to the substrate surface Wf during the freezing process.

  4 is a perspective view showing a configuration of a cooling gas discharge nozzle provided in the substrate processing apparatus of FIG. The cooling gas discharge nozzle 3 is formed in a covered cylindrical shape, and its inner bottom surface is directed downward. The cooling gas discharge nozzle 3 has a substantially disc-shaped lid portion 301 whose lower surface is the inner bottom surface of the covered cylindrical body, and a cylindrical side wall portion extending downward from the edge of the lid portion 301. 302. The cooling gas discharge nozzle 3 has a circulation space S1 in which the cooling gas can flow. This distribution space S1 constitutes a cylindrical internal space surrounded by the lid portion 301 and the side wall portion 302. A discharge port 303 that discharges the cooling gas that flows through the flow space S <b> 1 opens downward in the vertical direction at the front end (lower end) of the cooling gas discharge nozzle 3.

  Further, the substantially central portion of the lid 301 is connected to the gas introduction pipe 33 so that the cooling gas can be introduced from the gas introduction pipe 33 into the circulation space S1 in the downward direction in the vertical direction. That is, the opening 304 is opened at the connection position between the cooling gas discharge nozzle 3 (substantially central portion of the lid 301) and the gas introduction pipe 33, and the cooling gas that flows through the gas introduction pipe 33 through the opening 304. Is introduced downward into the distribution space S1 in the vertical direction. Here, the area of the cross section CS1 of the flow space S1 in the surface direction (horizontal direction) in the plane of the substrate surface Wf is larger than the area of the flow path section CS2 of the gas introduction pipe 33. In this embodiment, for example, the area of the cross section CS1 of the circulation space S1 is set to be 15 to 20 times larger than the area of the flow path cross section CS2 of the gas introduction pipe 33. Accordingly, the cooling gas introduced into the circulation space S1 from the gas introduction pipe 33 spreads in the circulation space S1 and is discharged from the discharge port 303.

  Returning to FIG. 1, the description will be continued. The rotation support shaft 21 of the spin chuck 2 is a hollow shaft. A processing liquid supply pipe 25 for supplying DIW to the back surface Wb of the substrate W is inserted into the rotary spindle 21. The processing liquid supply tube 25 extends to a position close to the lower surface (back surface Wb) of the substrate W held by the spin chuck 2, and the processing liquid that discharges DIW toward the center of the lower surface of the substrate W at the tip thereof. A nozzle 27 is provided. The processing liquid supply pipe 25 is connected to the DIW supply unit 16 (FIG. 2), and DIW is supplied from the DIW supply unit 16.

  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 gas supply path 29 is connected to the dry gas supply unit 17 (FIG. 2), and nitrogen gas can be supplied as a dry gas to a space formed between the spin base 23 and the substrate back surface Wb. In this embodiment, nitrogen gas is supplied from the dry gas supply unit 17 as a dry gas. However, air or other inert gas may be discharged instead of the nitrogen gas.

  Further, a disc-shaped blocking member 5 having an opening at the center is provided above the spin chuck 2. The blocking member 5 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 5 is equal to or larger than the diameter of the substrate W. The blocking member 5 is mounted substantially horizontally on the lower end portion of the support shaft 51 having a substantially cylindrical shape, and the support shaft 51 is held rotatably about a vertical axis passing through the center of the substrate W by an arm 52 extending in the horizontal direction. . The arm 52 is connected to a blocking member rotating mechanism 53 and a blocking member lifting mechanism 54.

  The blocking member rotating mechanism 53 rotates the support shaft 51 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 53 is configured to rotate the blocking member 5 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 54 can cause the blocking member 5 to be close to and opposed to the spin base 23 in accordance with an operation command from the control unit 4, or to be separated. Specifically, the control unit 4 operates the blocking member elevating mechanism 54 so that when the substrate W is loaded into and unloaded from the apparatus, the control unit 4 is moved to a separation position (position shown in FIG. 1) above the spin chuck 2. The blocking member 5 is raised. On the other hand, when a predetermined process is performed on the substrate W, the blocking member 5 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 51 is finished to be hollow, and a gas supply path 55 communicating with the opening of the blocking member 5 is inserted into the support shaft 51. The gas supply path 55 is connected to the dry gas supply unit 17, and nitrogen gas is supplied from the dry gas supply unit 17. In this embodiment, nitrogen gas is supplied from the gas supply path 55 to the space formed between the blocking member 5 and the substrate surface Wf during the drying process after the cleaning process for the substrate W. A liquid supply pipe 56 communicating with the opening of the blocking member 5 is inserted into the gas supply path 55, and a nozzle 57 is coupled to the lower end of the liquid supply pipe 56. The liquid supply pipe 56 is connected to the DIW supply unit 16, and DIW can be discharged from the nozzle 57 toward the substrate surface Wf when DIW is supplied from the DIW supply unit 16.

  Next, a cleaning process operation in the substrate processing apparatus configured as described above will be described with reference to FIG. FIG. 5 is a flowchart showing the operation of the substrate processing apparatus of FIG. In this apparatus, when an unprocessed substrate W is carried into the processing chamber 1, the control unit 4 controls each part of the apparatus to perform a series of cleaning processes (liquid film formation + liquid film freezing) on the surface Wf of the substrate W. + Film removal). Here, a fine pattern may be formed on the substrate surface Wf. That is, the substrate surface Wf is a pattern formation surface. Therefore, in this embodiment, the substrate W is carried into the processing chamber 1 with the substrate surface Wf facing upward, and is held by the spin chuck 2 (step S1). Note that the blocking member 5 is located at a separated position to prevent interference with the substrate W.

  When the unprocessed substrate W is held on the spin chuck 2, the blocking member 5 is lowered to the facing position and is disposed close to the substrate surface Wf. As a result, the substrate surface Wf is covered in a state of being close to the substrate facing surface of the blocking member 5 and is blocked from the ambient atmosphere of the substrate W. Then, the control unit 4 drives the chuck rotating mechanism 22 to rotate the spin chuck 2 and supplies DIW from the nozzle 57 to the substrate surface Wf. Then, by rotating the substrate W at a predetermined rotation speed, the DIW supplied to the substrate surface is uniformly spread outward in the radial direction of the substrate W, and part of the DIW is shaken out of the substrate. Thereby, the thickness of the liquid film is uniformly controlled over the entire surface of the substrate surface Wf, and a liquid film (water film) 11f having a predetermined thickness is formed on the entire surface of the substrate Wf (step S2).

  When the liquid film forming process is completed, the freezing process is performed on the substrate W held on the spin chuck 2 with the liquid film 11f formed on the substrate surface Wf. That is, the control unit 4 disposes the blocking member 5 in the separated position and moves the cooling gas discharge nozzle 3 from the standby position Ps to the cooling gas supply start position, that is, the rotation center position Pc of the substrate W. Subsequently, the cooling gas is discharged from the cooling gas discharge nozzle 3 toward the surface Wf of the substrate W being rotationally driven. Thereby, the liquid film 11f formed on the substrate surface Wf is locally frozen. Then, the cooling gas discharge nozzle 3 is gradually moved toward the edge position Pe of the substrate W while discharging the cooling gas. As a result, as shown in FIG. 3, the region (frozen region) where the liquid film 11f is frozen in the surface region of the substrate surface Wf is expanded from the central portion to the peripheral portion of the substrate surface Wf. As a result, the entire liquid film 11f formed on the substrate surface Wf is frozen, and a frozen film (ice film) 13f is formed on the entire surface of the substrate surface Wf (step S3).

  Here, the cooling gas from the cooling gas supply unit 15 is supplied to the cooling gas discharge nozzle 3 via the gas introduction pipe 33. For this reason, while the cooling gas flows through the gas introduction pipe 33, heat from the external atmosphere is absorbed, and the temperature of the cooling gas rises. As a result, it may be difficult to freeze the liquid film 11f. Therefore, in this embodiment, in order to prevent the temperature of the cooling gas reaching the substrate W from decreasing to a temperature necessary for freezing the liquid film 11f (at least below the freezing point), the cooling gas is supplied from the cooling gas supply unit 15. The flow rate of the cooling gas supplied toward the discharge nozzle 3 is increased.

  Here, if the flow passage cross-sectional area of the gas introduction pipe and the flow passage cross-sectional area of the distribution space are set to the same size, cooling is introduced from the gas introduction pipe to the distribution space and flows through the distribution space. The gas flow rate is almost the same. As a result, when the flow rate of the cooling gas flowing through the gas introduction pipe is increased, the cooling gas may be discharged from the nozzle in a state where the flow rate is increased, and the liquid film may be dried.

  On the other hand, according to this embodiment, the area of the cross section CS1 of the flow space S1 in the surface direction (horizontal direction) in the plane of the substrate surface Wf with respect to the area of the flow path cross section CS2 of the gas introduction pipe 33 is It is set to be large. As a result, the cooling gas introduced into the circulation space S1 from the gas introduction pipe 33 spreads in the circulation space S1, and is discharged from the discharge port 303 toward the liquid film 11f. For this reason, the flow rate of the cooling gas introduced into the flow space S1 and flowing through the flow space S1 is smaller than the flow rate of the cooling gas flowing through the gas introduction pipe 33. Thereby, even if the flow velocity of the cooling gas flowing through the gas introduction pipe 33 is increased, the flow velocity of the cooling gas can be reduced inside the nozzle. Accordingly, the liquid film 11f can be reliably frozen while preventing the liquid film 11f from drying.

  When the liquid film freezing process is performed in this manner, the volume of the liquid film entering between the substrate surface Wf and the contaminants adhering to the substrate surface Wf increases, and the contaminants are separated from the substrate surface Wf by a minute distance. Get away from. As a result, the adhesion force between the substrate surface Wf and the contaminant is reduced, and further, the contaminant is detached from the substrate surface Wf.

  When the liquid film freezing process is completed, the control unit 4 moves the cooling gas discharge nozzle 3 to the standby position Ps. Subsequently, a film removal process is performed on the substrate W. That is, the blocking member 5 is disposed at the opposing position, and the blocking member 5 is rotated together with the spin chuck 2. Further, nitrogen gas is supplied to the space between the substrate W and the spin base 23 and between the substrate W and the blocking member 5. Then, after the atmosphere around the substrate W is changed to an inert gas atmosphere, DIW is supplied from the nozzle 57 and the processing liquid nozzle 27 to the front and back surfaces Wf and Wb of the substrate W that is rotationally driven. As a result, the supply of DIW to the front and back surfaces Wf and Wb of the substrate W being rotated is started, and the film removal process by DIW is executed. As a result, the frozen film 13f containing the contaminant is melted and removed from the substrate surface Wf (step S4). That is, since the contaminant is in a state where the adhesion to the substrate surface Wf is reduced or detached from the substrate surface Wf, the contaminant is easily removed from the substrate surface Wf by removing the frozen film 13f from the substrate surface Wf. Is done.

  Thus, when the film removal process is completed and the cleaning process of the substrate W (liquid film formation + liquid film freezing + film removal) is completed (YES in step S5), the drying process of the substrate W is subsequently executed. On the other hand, depending on the surface state of the substrate surface Wf to be processed or the size and type of the contaminant to be removed, the contaminant may not be sufficiently removed from the substrate surface Wf by a single cleaning process. . In this case (NO in step S5), the liquid film freezing process and the film removing process are repeatedly executed after the film removing process is completed. That is, DIW remains on the substrate surface Wf after the film removal process. For this reason, even if a liquid film is not newly formed on the substrate surface Wf, the substrate surface Wf is covered with the remaining liquid film. Therefore, when the liquid film freezing process is executed after the film removal process, a frozen film composed of DIW is formed. Then, by removing the frozen film in the film removal process, contaminants attached to the substrate surface Wf are removed from the substrate surface Wf together with the frozen film. Thus, the contaminant removal is removed from the substrate surface Wf by repeatedly executing the film removal process and the liquid film freezing process a predetermined number of times.

  When the cleaning of the substrate W is completed, the control unit 4 increases the rotation speeds of the motors of the chuck rotating mechanism 22 and the blocking member rotating mechanism 53 to rotate the substrate W and the blocking member 5 at high speed. Thereby, the drying process (spin drying) of the substrate W is executed (step S6). After the drying process of the substrate W, the rotation of the substrate W and the blocking member 5 is stopped and the supply of nitrogen gas to the substrate W is stopped. Thereafter, the processed substrate W is unloaded from the processing chamber 1 (step S7).

  As described above, according to this embodiment, when the liquid film formed on the substrate surface is frozen, the surface of the substrate surface Wf from the gas introduction pipe 33 having a small channel cross-sectional area (area of the channel cross-section CS2). The cooling gas is introduced into the flow space S1 inside the nozzle having a large cross-sectional area (area of the cross-section CS1) in the surface direction. As a result, the cooling gas introduced into the circulation space S1 from the gas introduction pipe 33 spreads in the circulation space S1 and is discharged from the discharge port 303. For this reason, the flow rate of the cooling gas flowing through the flow space S <b> 1 can be made smaller than the flow rate of the cooling gas flowing through the gas introduction pipe 33. Thus, even when the flow rate of the cooling gas flowing through the gas introduction pipe 33 is increased in order to suppress the heat absorption from the external atmosphere to the cooling gas, the flow rate of the cooling gas is reduced inside the nozzle. Can do. Therefore, the liquid film can be reliably frozen while preventing the liquid film from drying.

  Further, according to this embodiment, the cooling gas discharge nozzle 3 is moved relative to the substrate W along the substrate surface Wf while locally discharging the cooling gas from the cooling gas discharge nozzle 3 toward the substrate surface Wf. ing. For this reason, it is possible to freeze the entire liquid film 11f formed on the substrate surface Wf while limiting the supply region of the cooling gas to a partial region on the substrate surface, and to suppress the consumption of the cooling gas. it can. Moreover, according to this embodiment, the cooling gas introduced into the circulation space S1 from the gas introduction pipe 33 spreads in the circulation space S1 and is discharged from the discharge port 303. For this reason, compared with the case where cooling gas is discharged from the nozzle which has the opening (discharge port) of the same cross-sectional area as the flow-path cross-sectional area of gas introduction piping, the supply range of the cooling gas with respect to the liquid film 11f is wide. . Therefore, the entire liquid film can be frozen more quickly than in the case where the cross-sectional area of the nozzle opening is the same as the cross-sectional area of the gas introduction pipe. As a result, the processing time required for the liquid film freezing process can be shortened and the throughput of the apparatus can be improved.

Second Embodiment
FIG. 6 is a view showing a second embodiment of the substrate processing apparatus according to the present invention. Specifically, FIG. 4A is a partial side view of the substrate processing apparatus, and FIG. 4B is a plan view thereof. The substrate processing apparatus according to the second embodiment differs greatly from the first embodiment in that the current plate 7 (the “plate” of the present invention is opposed to the opening at the connection position between the cooling gas discharge nozzle and the gas introduction pipe). Corresponds to a “shaped member”). Since other configurations and operations are basically the same as those in the first embodiment, the same reference numerals are given here and description thereof is omitted.

  In this embodiment, the cooling gas discharge nozzle 3 </ b> A includes a square plate-like lid portion 311 and a square-shaped side wall portion 312 extending downward from an end edge portion of the lid portion 311. A substantially central portion of the lid 311 is connected to the gas introduction pipe 35, and the cooling gas can be introduced from the gas introduction pipe 35 into the circulation space S2 provided inside the cooling gas discharge nozzle 3A. That is, an opening 314 is formed at a connection position between the cooling gas discharge nozzle 3 </ b> A (substantially central portion of the lid 311) and the gas introduction pipe 35, and the cooling gas that flows through the gas introduction pipe 35 through the opening 314. Is introduced into the distribution space S2. Here, the cross-sectional area of the flow space S2 in the surface direction in the plane of the substrate surface Wf is larger than the cross-sectional area of the gas introduction pipe 35.

  The rectifying plate 7 is disposed in the circulation space S2 in a horizontal posture with its surface 7a facing the opening 314. That is, the surface 7a of the rectifying plate 7 is arranged so as to be substantially parallel to the surface direction in the plane of the substrate surface Wf. The planar size of the surface 7a of the rectifying plate 7 is configured to be equal to or slightly larger than the opening area of the opening 314 (the cross-sectional area of the gas introduction pipe 35). Further, the rectifying plate 7 is disposed close to the opening 314, and the distance G between the rectifying plate 7 and the opening 314 is set to about 5 mm, for example.

  According to the above-described configuration, the gas cross-sectional area in the surface direction in the surface of the substrate surface Wf from the gas introduction pipe 35 having a small flow path cross-sectional area through the opening 314 is vertically downward to the flow space S2 inside the nozzle. Cooling gas is introduced. For this reason, the cooling gas introduced into the circulation space S2 from the opening 314 spreads in the circulation space S2, and the flow rate of the cooling gas introduced into the circulation space S2 in the same manner as in the first embodiment is equal to that of the gas introduction pipe 35. It becomes smaller than the flow rate of the cooling gas flowing inside. Further, the cooling gas introduced into the circulation space S2 collides with the surface 7a of the rectifying plate 7 disposed so as to face the opening 314, and is rectified in a direction substantially parallel to the surface direction of the substrate surface Wf. For this reason, it is possible to effectively reduce the flow rate of the cooling gas in the direction substantially perpendicular to the surface direction in the plane of the substrate surface Wf via the flow path 315 located on the side of the rectifying plate 7.

  As described above, according to this embodiment, the flow rate of the cooling gas can be reduced in two stages inside the nozzle of the cooling gas discharge nozzle 3A. For this reason, the flow rate of the cooling gas supplied toward the liquid film 11f can be further reduced, and the liquid film 11f can be reliably prevented from drying.

<Third Embodiment>
FIG. 7 is a view showing a third embodiment of the substrate processing apparatus according to the present invention. The substrate processing apparatus according to the third embodiment is greatly different from the first and second embodiments in that the cooling gas introduced from the gas introduction pipe into the cooling gas discharge nozzle collides with the inner wall surface of the cooling gas discharge nozzle. It is a point that is rectified. Since other configurations and operations are basically the same as those of the first and second embodiments, the same reference numerals are given here and description thereof is omitted.

  In this embodiment, the cooling gas discharge nozzle 3 </ b> B extends downward (vertical direction) to the lid portion 321 whose lower surface is the inner bottom surface of the covered cylindrical body and the edge of the lid portion 321. And a cylindrical side wall portion 322. And the gas introduction piping 37 is connected to the upper part position of the side wall part 322, and cooling gas can be introduce | transduced from the gas introduction piping 37 to distribution | circulation space S3 provided in the inside of the cooling gas discharge nozzle 3B. The gas introduction pipe 37 extends in a direction (horizontal direction) substantially parallel to the surface direction in the plane of the substrate surface Wf. In addition, the cross-sectional area of the circulation space S3 in a plane orthogonal to the cooling gas flow discharged toward the substrate surface Wf is larger than the cross-sectional area of the gas introduction pipe 37.

  According to the configuration described above, the cooling gas is introduced into the circulation space S3 from the direction substantially parallel to the surface direction in the plane of the substrate surface Wf through the gas introduction pipe 37. And the cooling gas introduced into distribution space S3 spreads in distribution space S3, and the flow velocity of cooling gas decelerates. Further, the cooling gas introduced into the circulation space S3 enters the inner wall surface 322a of the side wall portion 322 from a direction substantially parallel to the surface direction in the plane of the substrate surface Wf, collides with the 322a, and is rectified. For this reason, it is possible to effectively reduce the flow velocity of the cooling gas in the direction substantially perpendicular to the surface direction in the plane of the substrate surface Wf.

  As described above, according to this embodiment, the flow rate of the cooling gas can be reduced in two stages inside the nozzle of the cooling gas discharge nozzle 3B. For this reason, the flow rate of the cooling gas supplied toward the liquid film 11f can be further reduced, and the liquid film 11f can be reliably prevented from drying. Further, according to this configuration, it is not necessary to additionally provide a member for rectifying the cooling gas introduced into the circulation space S3, so that the configuration of the apparatus can be simplified.

<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 cooling gas is supplied to the liquid film 11f formed on the substrate surface Wf to form the frozen film 13f on the substrate surface Wf. However, the substrate is frozen not only on the substrate surface Wf but also on the substrate back surface Wb. A film (back-side frozen film) may be formed (FIG. 8).

  FIG. 8 is a view showing a modification of the substrate processing apparatus according to the present invention. In this embodiment, the liquid films 11f and 11b are formed on the front and back surfaces Wf and Wb of the substrate W. Then, as in the first embodiment, while rotating the substrate W, the cooling gas is locally discharged from the cooling gas discharge nozzle 3 toward the substrate surface Wf and the cooling gas discharge nozzle 3 is swung. At this time, the cold heat of the cooling gas supplied to the substrate surface Wf side is conducted to the back side liquid film 11b through the substrate W. As a result, the region (frozen region) where the back surface side liquid film 11b is frozen in the surface region of the substrate back surface Wb is expanded simultaneously with the frozen region on the substrate surface Wf side, and the frozen film (back surface side freezing) is spread over the entire surface of the substrate back surface Wb. Film) 13b is formed. Moreover, in this embodiment, the cooling gas introduced into the circulation space S1 from the gas introduction pipe 33 spreads in the circulation space S1 and is discharged from the cooling gas discharge nozzle 3. For this reason, the surface side frozen film 13f and the back side frozen film 13b can be quickly formed on the front and back surfaces Wf and Wb of the substrate W, respectively. Thereafter, by removing the frozen film 13f and the frozen film 13b from the substrate W, the front and back surfaces Wf and Wb of the substrate W can be cleaned without reversing the substrate W or the like.

  In the first and second embodiments, the cooling gas is introduced into the flow spaces S1 and S2 along the direction perpendicular to the surface direction in the plane of the substrate surface Wf (the normal direction of the substrate surface Wf). However, the direction in which the cooling gas is introduced into the circulation spaces S1 and S2 is not limited to this. For example, by disposing the cooling gas discharge nozzles 3 and 3A in a posture inclined with respect to the normal direction of the substrate surface Wf, the cooling gas from the gas introduction pipes 33 and 35 is inclined with respect to the normal direction of the substrate surface Wf. You may make it introduce into distribution space S1, S2 from the direction made. Even in this case, the cross-sectional area of the flow spaces S1, S2 in the plane orthogonal to the cooling gas flow discharged toward the substrate surface Wf is larger than the cross-sectional area of the gas introduction pipes 33, 35. Therefore, the flow rate of the cooling gas introduced into the flow spaces S1 and S2 and flowing through the flow spaces S1 and S2 is smaller than the flow rate of the cooling gas flowing through the gas introduction pipes 33 and 35. Become. As a result, the flow rate of the cooling gas can be reduced inside the nozzle even when the flow rate of the cooling gas flowing through the inside of the gas introduction pipe is increased to suppress heat absorption from the external atmosphere to the cooling gas. it can. Therefore, the liquid film can be reliably frozen while preventing the liquid film from drying.

  In the above embodiment, the cooling gas discharge nozzles 3, 3A and 3B are moved between the rotation center position Pc of the substrate W and the edge position Pe of the substrate W while rotating the substrate W, thereby discharging the cooling gas. Although the nozzles 3, 3A and 3B are moved relative to the substrate W, the configuration for moving the cooling gas discharge nozzles 3, 3A and 3B relative to the substrate W is not limited to this. For example, the freezing process may be performed while moving the substrate W in a predetermined direction with the cooling gas discharge nozzle fixedly arranged. Further, the freezing process may be executed while moving both the cooling gas discharge nozzle and the substrate. Furthermore, it is not essential to move the cooling gas discharge nozzle relative to the substrate W. Depending on the size of the substrate W, the freezing process may be executed with both the cooling gas discharge nozzle and the substrate fixedly arranged. .

  In the above embodiment, the liquid film is formed on the substrate W using DIW. However, in addition to DIW, carbonated water, hydrogen water, diluted ammonia water (for example, about 1 ppm), diluted hydrochloric acid, etc. A liquid film may be formed using a rinse liquid. Furthermore, a liquid film may be formed using a chemical solution in addition to the rinse solution.

  In the above embodiment, the frozen film is removed from the substrate W using DIW in the film removal process. In addition to DIW, carbonated water, hydrogen water, diluted ammonia water (eg, about 1 ppm), diluted concentration is used. A rinse solution such as hydrochloric acid may be used. Furthermore, before the rinse treatment with the rinse solution is performed, the chemical solution treatment may be performed using a chemical solution such as an SC1 solution (mixed aqueous solution of ammonia water and hydrogen peroxide solution) as the film removal process. By using such a chemical solution, contaminants can be effectively removed from the substrate W.

  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.

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 operation | movement of the cooling gas discharge nozzle with which the substrate processing apparatus of FIG. 1 was equipped. FIG. 2 is a perspective view illustrating a configuration of a cooling gas discharge nozzle provided in the substrate processing apparatus of FIG. 1. It is a flowchart which shows operation | movement of the substrate processing apparatus of FIG. It is a figure which shows 2nd Embodiment of the substrate processing apparatus concerning this invention. It is a figure which shows 3rd Embodiment of the substrate processing apparatus concerning this invention. It is a figure which shows the deformation | transformation form of the substrate processing apparatus concerning this invention.

Explanation of symbols

2 ... Spin chuck (substrate holding means)
3, 3A, 3B ... Cooling gas discharge nozzle 7 ... Rectifying plate (plate-like member)
7a ... (of the current plate) 31 ... Nozzle moving mechanism (driving mechanism)
33, 35, 37 ... Gas introduction pipe 304, 314 ... Opening 322a ... Inner wall surface (of cooling gas discharge nozzle) 11b ... (Back side) Liquid film 11f ... (Front side) Liquid film CS1 ... (Flow in distribution space) Channel cross section CS2 ... Cross-channel cross section (of gas introduction pipe) S1, S2, S3 ... Distribution space W ... Substrate Wf ... Substrate surface

Claims (7)

In a substrate processing apparatus suitable for a freezing process for freezing a liquid film formed on a substrate surface,
Substrate holding means for holding the substrate in a state in which a liquid film is formed on the substrate surface;
A cooling gas discharge nozzle that has a circulation space for circulating a cooling gas having a temperature lower than the freezing point of the liquid constituting the liquid film therein, and that discharges the cooling gas in the circulation space toward the liquid film;
A gas introduction pipe connected to the cooling gas discharge nozzle and for introducing a cooling gas into the circulation space ;
A drive mechanism for moving the cooling gas discharge nozzle relative to the substrate surface while facing the cooling gas discharge nozzle apart from the substrate surface ;
The cross-sectional area of the flow space in the plane perpendicular to respect the cooling gas flow discharged toward the substrate surface much larger than the flow path cross-sectional area of the gas introduction pipe,
The substrate, wherein the driving mechanism moves the cooling gas discharge nozzle relative to the substrate while discharging the cooling gas locally from the cooling gas discharge nozzle toward the substrate surface. Processing equipment. A plate-like member, the surface of which is disposed opposite to the opening portion opened at the connection position of the cooling gas discharge nozzle and the gas introduction pipe in the circulation space;
The gas introduction pipe introduces a cooling gas into the circulation space from the opening and rectifies the collision of the cooling gas against the surface of the plate member, and the cooling gas discharge nozzle discharges the rectified cooling gas. Item 2. The substrate processing apparatus according to Item 1.   The substrate processing apparatus according to claim 2, wherein the surface of the plate-like member is disposed so as to be substantially parallel to a plane orthogonal to a cooling gas flow discharged toward the substrate surface.   2. The gas introduction pipe introduces a cooling gas into the flow space and rectifies the cooling gas by colliding with the inner wall surface of the cooling gas discharge nozzle, and the cooling gas discharge nozzle discharges the rectified cooling gas. The substrate processing apparatus as described.   The substrate processing apparatus according to claim 4, wherein the gas introduction pipe introduces a cooling gas into the flow space from a direction substantially parallel to a surface direction in a plane of the substrate surface. In a substrate processing method suitable for a freezing process for freezing a liquid film formed on a substrate surface,
A substrate holding step for holding the substrate with a liquid film formed on the substrate surface;
A cooling gas is introduced from a gas introduction pipe connected to the cooling gas discharge nozzle into a circulation space that is provided inside the cooling gas discharge nozzle and distributes a cooling gas having a temperature lower than the freezing point of the liquid constituting the liquid film. Gas introduction process to
While the cooling gas introduced into the circulation space is discharged toward the liquid film from the cooling gas discharge nozzle spaced apart from the substrate surface, the cooling gas discharge nozzle is relatively moved along the substrate surface. and a gas discharge process to Ru is,
The substrate processing method characterized by the cross-sectional area of the said circulation space in the surface orthogonal to the cooling gas flow discharged toward the said substrate surface being larger than the flow-path cross-sectional area of the said gas introduction piping.   The substrate processing method according to claim 6, wherein in the gas discharging step, the entire liquid film on the substrate surface is frozen.

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