JP2006179764A - Substrate processing apparatus and particle removing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technology for efficiently removing particles from the surface of a wafer or from liquid in a substrate processing apparatus. <P>SOLUTION: In the substrate processing apparatus 1, a part of nitrogen gas dissolves into pure water in a micro bubble generator 33, and the other part becomes micro bubbles. Thus, nitrogen gas is dissolved and pure water comprising the micro bubbles is supplied to the wafer W in a processing tank 10. Sizes of respective micro bubbles are very small and the micro bubbles have electrification property. Thus, particles existing on the surface of the wafer W or in pure water are efficiently adsorbed. The particles are discharged outside the processing tank 10 with the micro bubbles. Since nitrogen gas is dissolved in pure water, water itself cannot be charged easily. Consequently, pure water is prevented from absorbing the new particles from respective parts of the processor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for removing particles from a surface of a substrate or from a liquid in a substrate processing apparatus that performs processing with a liquid on a substrate such as a semiconductor substrate, a glass substrate for liquid crystal display, or a glass substrate for a photomask.

  2. Description of the Related Art Conventionally, in a substrate manufacturing process, a substrate processing apparatus that supplies a liquid such as pure water or a chemical solution to a substrate and performs a predetermined process is known. Such a substrate processing apparatus mainly includes a batch-type substrate processing apparatus for immersing and processing a plurality of substrates at once in a liquid stored in a processing tank, and a surface of the substrate held by the holding means one by one. And a single-wafer type substrate processing apparatus for discharging and processing liquid.

  In these substrate processing apparatuses, particles adhering to the substrate and particles floating in the liquid are appropriately removed. Usually, a liquid flow is formed along the surface of the substrate, and particles are transported and removed by the action of the liquid flow. In some cases, bubbles are supplied into the liquid, and particles are adsorbed to the bubbles to be transported and removed. In a conventional substrate processing apparatus, a technique for supplying bubbles into a liquid is disclosed in Patent Document 1, for example.

JP 7-58078 A

  As described above, in the conventional substrate processing apparatus, particles are removed by the action of a liquid flow or the action of bubbles. However, when the particles are removed only by the action of the liquid flow, the removal efficiency has a certain limit. Even when bubbles are used, the size of bubbles generated from a normal bubbler as disclosed in Patent Document 1 is overwhelmingly larger than the size of particles, and the optimum size for removing particles There wasn't. In recent years, the level of particles allowed in substrate processing has become stricter, and a technique capable of removing particles more efficiently is required.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique capable of efficiently removing particles from the surface of a substrate or from a liquid in a substrate processing apparatus.

In order to solve the above-mentioned problem, the invention according to claim 1 is a substrate processing apparatus for processing a substrate with a liquid, and supplies the liquid to the holding means for holding the substrate and the substrate held by the holding means. Liquid supply means, wherein the liquid supply means includes gas dissolving means for dissolving a predetermined gas in the liquid and microbubble generating means for generating microbubbles in the liquid.

  The invention according to claim 2 is the substrate processing apparatus according to claim 1, wherein the microbubble generating means forms a gas-liquid two-layer flow with the liquid and a predetermined gas, and the gas-liquid two-layer flow It is characterized in that the flow is sheared to generate microbubbles.

  A third aspect of the present invention is the substrate processing apparatus according to the first aspect, wherein the microbubble generating means bubbles a part of the gas dissolved by the gas dissolving means by supersaturation to generate microbubbles. Is generated.

  The invention according to claim 4 is the substrate processing apparatus according to claim 3, wherein the gas dissolving means pressurizes and dissolves a predetermined gas in the liquid, and the microbubble generating means is the gas dissolving means. A part of the gas pressure-dissolved under pressure is supersaturated by a pressure drop after pressure-dissolution and includes means for generating microbubbles.

  The invention according to claim 5 is the substrate processing apparatus according to claim 3 or 4, wherein the microbubble generating means superheats a part of the gas dissolved by the gas dissolving means, A means for generating microbubbles is included.

  The invention according to claim 6 is a particle removal method for removing particles from the surface of a substrate or from a liquid, the first step of dissolving a predetermined gas in the liquid, and generating microbubbles in the liquid A second step and a third step of forming the liquid flow along the surface of the substrate.

  The invention according to claim 7 is the particle removal method according to claim 6, wherein in the second step, a gas-liquid two-layer flow is formed by the liquid and a predetermined gas, and the gas-liquid 2 A laminar flow is sheared to generate microbubbles.

  The invention according to claim 8 is the particle removal method according to claim 6, wherein in the second step, a part of the gas dissolved in the first step is bubbled by supersaturation, It is characterized by generating microbubbles.

  The invention according to claim 9 is the particle removal method according to claim 8, wherein, in the first step, a predetermined gas is dissolved under pressure in the liquid, and the second step includes the first step. A part of the gas pressure-dissolved in step 1 is supersaturated by a pressure drop after pressure-dissolving to generate microbubbles.

  The invention according to claim 10 is the particle removal method according to claim 8 or 9, wherein in the second step, a part of the gas dissolved in the first step is supersaturated by heating. And generating microbubbles.

  According to invention of Claims 1-10, the particle which exists in the surface of a board | substrate or in a liquid can be made to adsorb | suck to a microbubble, and it can convey and remove with a microbubble. Since the size of each bubble is minute, the microbubble has a large surface area as a whole, and adsorbs particles efficiently. Moreover, since microbubbles have charging properties, particles are attracted and attracted efficiently by electrostatic action. On the other hand, since a predetermined gas is dissolved in the liquid, the liquid itself is not easily charged, and the liquid can prevent new particles from being absorbed from each part of the apparatus and adhered to the substrate. By these actions, particles can be efficiently removed.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<1. First Embodiment>
First, a first embodiment of the present invention will be described. The first embodiment is an embodiment when the present invention is applied to a batch-type substrate processing apparatus. FIG. 1 is a longitudinal sectional view of the substrate processing apparatus 1 according to the first embodiment cut along a plane parallel to the substrate W. FIG. 1 also shows the configuration of the piping and control system. FIG. 2 is a longitudinal sectional view of the substrate processing apparatus 1 cut along a plane perpendicular to the substrate W.

  As shown in FIGS. 1 to 2, the substrate processing apparatus 1 mainly includes a processing tank 10, a lifter 20, a pure water supply system 30, a drainage system 40, an ultrasonic generator 50, and a controller 60. With.

  The processing tank 10 is a container for storing pure water as a processing liquid. By immersing the substrate W in pure water stored in the processing tank 10, the substrate is subjected to processing such as cleaning. A discharge section 11 is provided at the bottom of the processing tank 10, and pure water is discharged from the discharge section 11 into the processing tank 10 as indicated by an arrow in FIG. 1. Moreover, the upper surface of the processing tank 10 is open | released, and the outer tank 12 is provided in the upper end of the outer surface. The pure water discharged from the discharge unit 11 flows upward in the treatment tank 10 and eventually overflows from the upper opening to the outer tank 12.

  The lifter 20 includes three holding rods 23 between the lifter head 21 and the holding plate 22. A plurality of holding grooves (not shown) are formed in the holding bar 23, and the plurality of substrates W are held in a standing posture on the holding grooves. A lifter drive unit 24 having a servo motor, a timing belt, and the like is connected to the lifter 20. When the lifter driving unit 24 is operated, the lifter 20 moves up and down, and the plurality of substrates W move between the immersion position in the processing tank 10 and the lifting position above the processing tank 10. When processing the substrate W with pure water, the lifter 20 is lowered and the substrate W is immersed in the processing bath 10. When not processing, the lifter 20 is raised and the substrate W is pulled up above the processing bath 10.

  The pure water supply system 30 is a piping system for supplying pure water to the discharge unit 11. The pure water supply system 30 includes a pure water supply source 31, a nitrogen gas supply source 32, a microbubble generator 33, pipes 34 and 35, and on-off valves 36 and 37. A pipe 34 extends from the pure water supply source 31, and an open / close valve 36 is inserted in the pipe 34. A pipe 35 extends from the nitrogen gas supply source 32, and an open / close valve 37 is interposed in the pipe 35. The pipe 35 joins the pipe 34 on the downstream side of the on-off valve 37. The joined pipe 34 is connected to the discharge unit 11 via the microbubble generating unit 33. The microbubble generator 33 is a device that generates microbubbles that are microbubbles in the micrometer order. The microbubble generator 33 has a gas-liquid mixing pump 33 a, a turning accelerator 33 b, and a disperser 33 c in the pipe 34.

  In such a configuration, when the on-off valve 36 and the on-off valve 37 are opened, pure water and nitrogen gas are introduced into the gas-liquid mixing pump 33a. Pure water and nitrogen gas are mixed in the gas-liquid mixing pump 33a and sent to the turning accelerator 33b. The turning accelerator 33b accelerates and turns pure water and nitrogen gas, forms a gas-liquid two-layer flow, and sends it to the disperser 33c. The disperser 33c hydrodynamically shears the fed gas-liquid two-layer flow to form microbubbles of nitrogen gas. Then, pure water containing the microbubbles is discharged from the discharge unit 11 into the treatment tank 10. When the on-off valve 37 is closed and only the on-off valve 36 is opened, only pure water not containing microbubbles is supplied from the discharge unit 11 into the processing tank 10.

  In the gas-liquid mixing pump 33a, the turning accelerator 33b, and the dispersing device 33c, nitrogen gas is vigorously mixed into pure water when generating microbubbles. For this reason, a part of the nitrogen gas supplied from the nitrogen gas supply source 32 is dissolved in pure water. That is, in the substrate processing apparatus 1, the microbubble generator 33 also functions as a means for dissolving nitrogen gas in pure water.

  The drainage system 40 includes a pipe 41 that connects the outer tub 12 and a drainage line in the facility. The pure water that has overflowed from the processing tank 10 to the outer tank 12 is discharged to the drainage line through the pipe 41.

  The ultrasonic generator 50 includes a propagation tank 51 disposed below the processing tank 10 and an ultrasonic transducer 52 provided on the back surface of the bottom of the propagation tank 51. The propagation tank 51 stores a propagation liquid for propagating ultrasonic vibrations. When the ultrasonic vibrator 52 is operated, ultrasonic vibration is generated. The ultrasonic vibration vibrates the bottom of the propagation tank 51, the propagation liquid, the bottom of the processing tank 10, and the pure water in the processing tank 10 in this order. Propagate to the surface.

  The control unit 60 is electrically connected to the lifter driving unit 24, the microbubble generation unit 33, the on-off valves 36 and 37, the ultrasonic vibrator 52, and the like, and controls these operations.

  Next, the operation of the substrate processing apparatus 1 having such a configuration will be described below. 3 to 6 are diagrams illustrating the operation of each stage of the substrate processing apparatus 1. These operations proceed when the control unit 60 controls the lifter driving unit 24, the microbubble generating unit 33, the on-off valves 36 and 37, the ultrasonic transducer 52, and the like.

  First, as shown in FIG. 3, the lifter 20 is lowered, and the plurality of substrates W are immersed in pure water stored in advance in the treatment tank 10. Note that the lifter 20 may be lowered first, and then the on-off valve 36 (see FIG. 1) may be opened to store pure water in the treatment tank 10.

  Next, as shown in FIG. 4, application of ultrasonic vibration and supply of microbubbles are performed. The ultrasonic vibration is generated by operating the ultrasonic vibrator 52 and propagates toward the treatment tank 10 using the propagation liquid in the propagation tank 51 as a medium as indicated by the broken line arrow in FIG. In the processing tank 10, the ultrasonic vibration propagates to the surface of the substrate W via pure water. On the other hand, microbubbles are generated by opening the on-off valves 36 and 37 (see FIG. 1) and operating the microbubble generator 33 (see FIG. 1). The generated microbubbles are discharged from the discharge unit 11 together with pure water, float around the substrate W toward the upper side of the processing tank 10, and eventually overflow to the outer tank 12 together with pure water.

  At this time, the particles adhering to the substrate W are released from the surface of the substrate W under the impact of ultrasonic vibration from the ultrasonic transducer 52. Moreover, in the processing tank 10, the flow of the pure water which goes to the upper direction of the processing tank 10 is formed, and the microbubble floats toward the upper direction of the processing tank 10 in it. For this reason, the particles released from the surface of the substrate W are adsorbed by the microbubbles and are transported together with the microbubbles above the processing bath 10. Since the size of each bubble is minute, the microbubble has a large surface area (area of gas-liquid interface) as a whole. For this reason, the particles released from the substrate W are efficiently adsorbed. In addition, since microbubbles have a charging property, particles are attracted and adsorbed efficiently by electrostatic action. Thus, the microbubble which adsorb | sucked the particle overflows from the upper part of the processing tank 10 to the outer tank 12 with a pure water, and is discharged | emitted to the drainage line through the piping 41 (refer FIG. 1).

  After the application of ultrasonic vibration and the supply of microbubbles are continued for a predetermined time, the operation of the ultrasonic vibrator 52 is stopped and only the supply of microbubbles is continued as shown in FIG. Particles remaining in the pure water are adsorbed by the microbubbles and removed out of the treatment tank 10. This prevents particles remaining in the processing bath 10 from reattaching to the substrate W.

  Thereafter, as shown in FIG. 6, the lifter 20 is raised and the substrate W is pulled up from the processing tank 10. The processing of the substrate W in the substrate processing apparatus 1 ends here. In addition, a drying process is performed with respect to the board | substrate W in the state which pulled up the board | substrate W above the processing tank 10, or after conveying the board | substrate W to another apparatus.

  As described above, in this substrate processing apparatus 1, particles can be released from the substrate W by the impact of ultrasonic vibration, and the released particles can be adsorbed to the microbubbles and efficiently removed. In addition, since the ultrasonic vibration is applied while supplying the microbubble to the periphery of the substrate W, the microbubble can absorb the shock of the ultrasonic vibration, and the excessive shock to the substrate W can be reduced. That is, particles can be released from the substrate W while alleviating damage to the substrate W.

  In the substrate processing apparatus 1, a part of the nitrogen gas is dissolved in pure water in the microbubble generator 33. Therefore, pure water in which nitrogen gas is dissolved is supplied around the substrate W. Pure water (especially ultrapure water) is highly insulating and may be charged with static electricity due to friction with the inner wall of the pipe. However, when nitrogen gas is dissolved, the charge of such pure water is reduced. it can. For this reason, it can prevent that pure water itself absorbs a particle from each part of piping or processing tank 10 by an electrostatic effect, and increases the number of particles in pure water. Therefore, new particles can be prevented from adhering to the substrate W, and the particle removal efficiency can be improved.

  Further, pure water in which nitrogen gas is dissolved has a property of transmitting ultrasonic vibrations more efficiently than degassed pure water. For this reason, in this substrate processing apparatus 1, the ultrasonic vibration efficiently reaches the surface of the substrate W, and particles can be efficiently released from the surface of the substrate W.

<2. Second Embodiment>
Next, a second embodiment of the present invention will be described. The second embodiment is also an embodiment when the present invention is applied to a batch type substrate processing apparatus. FIG. 7 is a longitudinal sectional view of the substrate processing apparatus 2 according to the second embodiment cut along a plane parallel to the substrate W. The substrate processing apparatus 2 is different from the substrate processing apparatus 1 in the configuration of the microbubble generator 71 and the pump 72, and other parts are the same as the substrate processing apparatus 1. For this reason, parts other than the microbubble generating unit 71 and the pump 72 are denoted by the same reference numerals as those in FIG. 1 in FIG. A longitudinal sectional view of the substrate processing apparatus 2 taken along a plane perpendicular to the substrate W is the same as FIG.

  The microbubble generating unit 71 of the substrate processing apparatus 2 includes a degassing unit 71a, a gas dissolving unit 71b, and a heater 71c in the pipe 34. These deaeration unit 71 a, gas dissolution unit 71 b, and heater 71 c are electrically connected to the control unit 60. Further, the gas dissolving part 71 b is connected to the nitrogen gas supply source 32 via the pipe 35.

  In such a configuration, when the on-off valve 36 is opened and the pump 72 is operated, pure water is introduced from the pure water supply source 31 to the deaeration unit 71a. In the deaeration unit 71a, excess gas dissolved in the pure water is removed by decompression or the like, and the deaerated pure water is sent to the gas dissolution unit 71b. On the other hand, when the on-off valve 37 is opened, nitrogen gas is introduced from the nitrogen gas supply source 32 to the gas dissolving part 71b. In the gas dissolving part 71b, the introduced nitrogen gas is pressure-dissolved in pure water.

  The gas dissolving part 71b is in a high pressure environment in order to pressurize and dissolve nitrogen gas into pure water. However, when the pure water after dissolving the nitrogen gas exits the gas dissolving part 71b, the pressure around the pure water decreases to normal pressure. For this reason, in the gas dissolving part 71b in a high pressure environment, if nitrogen gas is dissolved in pure water to a level equal to or higher than the saturated dissolving concentration at normal pressure, the nitrogen is oversaturated due to the pressure drop when leaving the gas dissolving part 71b and cannot be completely dissolved. Gas is generated as minute microbubbles. FIG. 8 shows the saturated dissolution concentration of nitrogen gas with respect to pure water at normal pressure (atmospheric pressure). If pressure dissolution is performed in the gas dissolution unit 71b so that the nitrogen gas concentration in the pure water is higher than the saturation dissolution concentration in FIG. 8, microbubbles are generated due to a pressure drop when the gas dissolution unit 71b is exited. Will be. The amount of microbubbles generated here is adjusted by the pressure value in the gas dissolving part 71b and the supply amount of nitrogen gas.

  The pure water exiting the gas dissolving part 71b is introduced into the heater 71c in a state in which nitrogen gas is dissolved and part of the nitrogen gas is included as microbubbles. In the heater 71c, the introduced pure water is heated. As shown in FIG. 8, the saturated dissolution concentration of nitrogen gas decreases as the temperature increases. For this reason, the pure water in which nitrogen gas is dissolved becomes supersaturated again as the temperature rises, and nitrogen gas that cannot be completely dissolved is generated as microbubbles. The amount of microbubbles generated here is adjusted by the set temperature of the heater.

  As described above, in the microbubble generating unit 71 of the present embodiment, the first supersaturated state is created by the pressure drop when pure water exits the gas dissolving unit 71b, and the first microbubbles are generated. In addition, a second supersaturated state is created by the rise in the temperature of pure water when passing through the heater 71c, and second microbubbles are generated. The first and second microbubbles may be generated together, or only one of them may be generated. For example, when pure water is to be supplied without heating, the heater 71c may not be operated and only the first microbubbles may be generated.

  In FIG. 7, the deaeration part 71a and the gas melt | dissolution part 71b which are the components of the microbubble generation | occurrence | production part 71 were shown notionally with the block. Specifically, the degassing part 71a and the gas dissolving part 71b can be realized by using a unit 710 as shown in FIG. The unit 710 of FIG. 9 has a configuration in which a water supply pipe 712 that passes through the axial center and an air supply path 713 that surrounds the periphery of the water supply pipe 712 are formed in a substantially cylindrical casing 711. Inside the water supply pipe 712 and the air supply path 713, pure water and nitrogen gas respectively flow in the directions of the arrows in the figure. The water supply pipe 712 and the air supply path 713 are partitioned by a hollow separator membrane 714 having gas permeability and liquid impermeability. The gas inlet 715 of the unit 710 is connected to the nitrogen gas supply source 32 via a pressure gauge 351, a regulator 352, and an on-off valve 37, and the gas outlet 716 of the unit 710 is connected via a pressure gauge 353 and a regulator 354. Connected to the vacuum pump. The pressure gauges 351 and 353 and the regulators 352 and 354 are electrically connected to the control unit 60 described above.

  In such a unit 710, when the on-off valve 37 is opened and the regulators 352 and 354 are controlled based on the outputs of the pressure gauges 351 and 353, the pressure of the nitrogen gas flowing through the air supply path 713 can be adjusted. The inside can be pressurized or depressurized. When the inside of the casing 711 is depressurized, excess gas precipitates from the pure water flowing through the water supply pipe 712 with supersaturation, and the gas flows out to the air supply path 713 through the hollow element separation membrane 714. On the other hand, when the inside of the casing 711 is pressurized, the nitrogen gas flowing through the air supply passage 713 is pressurized and dissolved into the pure water in the water supply pipe 712 through the hollow element separation membrane 714.

  That is, the unit 710 can be used as the deaeration unit 71a when the inside of the casing 711 is decompressed, and can be used as the gas dissolving unit 71b when the inside of the casing 711 is pressurized.

  Although this substrate processing apparatus 2 is different from the first embodiment in the configuration of the microbubble generating unit 71 as described above, it can perform the operations as shown in FIGS. 3 to 6 as in the first embodiment. . That is, after the substrate W is immersed in pure water in the processing tank 10, application of ultrasonic vibration and supply of microbubbles are performed.

  Therefore, also in this substrate processing apparatus 2, it is possible to obtain an effect of releasing particles from the substrate W by the impact of ultrasonic vibration and adsorbing the released particles to the microbubbles to remove them. Moreover, the effect which softens the excessive impact by ultrasonic vibration by microbubble can also be acquired.

  In the substrate processing apparatus 2 as well, a part of the nitrogen gas dissolved in the pure water in the gas dissolving part 71b continues to be dissolved in the pure water without being generated as microbubbles. For this reason, as in the first embodiment, the effect of reducing the charge of pure water itself and the effect of improving the propagation efficiency of ultrasonic vibration can be obtained.

  In such a substrate processing apparatus 2, processing for a predetermined time was actually performed, and the particle removal rate from the substrate W before and after the processing was examined. As a result, a result as shown in FIG. 10 was obtained. Conditions 1 to 4 in FIG. 10 are as follows. (1) Condition 1 is a case where nitrogen gas is not supplied into pure water and heating by the heater 71c is not performed. (2) Condition 2 is a case where the nitrogen gas dissolution concentration in the gas melting section 71b is 17.1 ppm and the heater 71c is not heated. Under condition 2, since the nitrogen gas dissolution concentration does not reach the saturation dissolution concentration, no microbubbles are generated. (3) Condition 3 is a case where the nitrogen gas dissolution concentration in the gas melting section 71b is 20.0 ppm and the heater 71c is heated to 41 ° C. Under condition 3, part of the dissolved nitrogen gas is generated as microbubbles due to supersaturation. (4) Condition 4 is a case where the nitrogen gas dissolution concentration in the gas melting section 71b is 23.0 ppm and heating by the heater 71c is not performed. Also in condition 4, a part of the dissolved nitrogen gas is generated as microbubbles due to supersaturation. Note that, in any of the conditions 1 to 4, the ultrasonic transducer 52 is operated.

  Comparing the result of condition 1 and the result of condition 2, it can be seen that the removal efficiency of particles is dramatically improved by dissolving nitrogen gas in pure water. Further, comparing the result of Condition 2 with the results of Conditions 3 and 4, it can be seen that the removal efficiency of particles is further improved by the generation of microbubbles.

<3. Third Embodiment>
Subsequently, a third embodiment of the present invention will be described. The third embodiment is an embodiment when the present invention is applied to a single wafer processing apparatus. FIG. 11 is a longitudinal sectional view of the substrate processing apparatus 3 according to the third embodiment. FIG. 11 also shows the configuration of the piping and control system.

  As shown in FIG. 11, the substrate processing apparatus 3 mainly includes a substrate holding unit 110, a pure water discharge unit 120, a pure water supply system 130, a pure water recovery unit 140, and a control unit 150.

  The substrate holding part 110 includes a disk-shaped base member 111 and a plurality of chuck pins 112 erected on the upper surface thereof. The chuck pins 112 are provided at three or more locations along the peripheral edge of the base member 111 in order to hold the circular substrate W. The substrate W is placed on the substrate support portion 112a of the plurality of chuck pins 112, and the outer surface is pressed and held by the chuck portion 112b. A rotation shaft 113 is suspended from the center of the lower surface side of the base member 111. The lower end of the rotating shaft 113 is connected to the electric motor 114. When the electric motor 114 is driven, the rotating shaft 113, the base member 111, and the substrate W held on the base member 111 rotate integrally.

  The pure water discharge unit 120 has a nozzle 121 for discharging pure water on the upper surface of the substrate W. An ultrasonic vibrator 122 is affixed to the top of the nozzle 121, and when the ultrasonic vibrator 122 is operated, ultrasonic vibration is applied to the pure water in the nozzle 121. The nozzle 121 is connected to the rotary shaft 124 via the link member 123, and the lower end of the rotary shaft 124 is connected to the electric motor 125. For this reason, when the electric motor 125 is driven, the rotating shaft 124, the link member 123, and the nozzle 121 rotate integrally, and the nozzle 121 moves relative to each part from the center part to the peripheral part of the substrate W. It becomes possible to discharge pure water.

  The pure water supply system 130 is a piping system for supplying pure water to the pure water discharge unit 120. The pure water supply system 130 includes a pure water supply source 131, a nitrogen gas supply source 132, a microbubble generator 133, pipes 134 and 135, and on-off valves 136 and 137. A pipe 134 extends from the pure water supply source 131, and an open / close valve 136 is interposed in the pipe 134. A pipe 135 extends from the nitrogen gas supply source 132, and an opening / closing valve 137 is interposed in the pipe 135. The pipe 135 joins the pipe 134 at the tip of the on-off valve 137. The joined pipe 134 is connected to the nozzle 121 via the microbubble generator 133. The pipe 134 is formed of a flexible member at least in the vicinity of the nozzle 121, and can follow the rotation of the nozzle 121.

  The microbubble generating unit 133 is a device that generates microbubbles that are microbubbles on the order of micrometers. The configuration of the microbubble generator 133 is the same as the microbubble generator 33 of the first embodiment, and has a gas-liquid mixing pump 133a, a swirl accelerator 133b, and a disperser 133c in the pipe 134.

  In such a configuration, when the on-off valve 136 and the on-off valve 137 are opened, pure water and nitrogen gas are introduced into the gas-liquid mixing pump 133a. Pure water and nitrogen gas are mixed in the gas-liquid mixing pump 133a and sent to the turning accelerator 133b. The turning accelerator 133b accelerates and turns pure water and nitrogen gas, forms a gas-liquid two-layer flow, and sends it to the disperser 133c. The disperser 133c hydrodynamically shears the fed gas-liquid two-layer flow to form nitrogen gas microbubbles. Then, pure water containing the microbubbles is discharged from the nozzle 121 to the upper surface of the substrate W. When the on-off valve 137 is closed and only the on-off valve 136 is opened, only pure water not containing microbubbles is supplied to the upper surface of the substrate W.

  In the gas-liquid mixing pump 133a, the swing accelerator 133b, and the disperser 133c, nitrogen gas is vigorously mixed into pure water when generating microbubbles. For this reason, a part of the nitrogen gas supplied from the nitrogen gas supply source 132 is dissolved in pure water. That is, in this substrate processing apparatus 3, the microbubble generator 133 also functions as a means for dissolving nitrogen gas in pure water.

  The pure water recovery unit 140 includes a guard member 141 that surrounds the periphery of the substrate W held on the base member 111. The guard member 141 has a cross-sectional shape that is open in an inwardly-shaped shape, and receives pure water scattered from the substrate W around the inner wall surface. A drainage port 142 is provided on a part of the bottom surface of the guard member 141. The pure water received by the guard member 141 is discharged from the drainage port 142 to the drainage line along the inner wall surface of the guard member 141.

  The controller 150 is electrically connected to the chuck pin 112, the electric motors 114 and 125, the ultrasonic vibrator 122, the microbubble generator 133, the on-off valves 136 and 137, and controls these operations.

  Next, the operation of the substrate processing apparatus 3 having such a configuration will be described below. 12 to 13 are diagrams illustrating the operation of each stage of the substrate processing apparatus 3. These operations proceed when the control unit 150 controls the chuck pin 112, the electric motors 114 and 125, the ultrasonic vibrator 122, the microbubble generation unit 133, the on-off valves 136 and 137, and the like.

  First, as shown in FIG. 12, the substrate W is placed on the base member 111, and the substrate W is gripped by the chuck pins 112. Then, the electric motor 114 is driven to rotate the substrate W together with the base member 111.

  Next, the on-off valves 136 and 137 (see FIG. 11) are opened and the microbubble generating unit 133 (see FIG. 11) is operated to discharge pure water containing microbubbles onto the upper surface of the substrate W as shown in FIG. To do. Further, the ultrasonic vibrator 122 is operated to apply ultrasonic vibration to the pure water discharged from the nozzle 121. The pure water discharged on the upper surface of the substrate W is shaken off outward by the centrifugal force accompanying the rotation of the substrate W, received by the guard member 141 (see FIG. 11), and then drained (see FIG. 11). To the drainage line.

  When pure water is discharged onto the surface of the substrate W, the particles adhering to the substrate W are released from the surface of the substrate W under the impact of ultrasonic vibration with pure water. Further, a flow toward the outside of pure water containing microbubbles is formed on the surface of the substrate W. For this reason, particles released from the surface of the substrate W due to the impact of ultrasonic vibration are adsorbed to the microbubbles and are transported outward together with the microbubbles. Since the size of each bubble is minute, the microbubble has a large surface area as a whole, and adsorbs particles efficiently. In addition, since microbubbles have charging properties, particles are efficiently adsorbed even by electrostatic action. In this way, the particles are swung out together with the microbubbles and discharged to the waste liquid line through the guard member 141 (see FIG. 11).

  After the discharge of the pure water is continued for a predetermined time, the ultrasonic vibrator 122 and the microbubble generator 133 (see FIG. 11) are stopped, and the on-off valves 136 and 137 (see FIG. 11) are closed. Stop dispensing. Then, the rotational speed of the electric motor 114 is increased to rotate the substrate W at a high speed. As a result, the pure water remaining on the upper surface of the substrate W is shaken outward to dry the substrate W. This completes the processing of the substrate W in the substrate processing apparatus 3.

  As described above, in this substrate processing apparatus 3, particles can be released from the substrate W by the impact of ultrasonic vibration, and the released particles can be adsorbed by the microbubbles and efficiently removed. In addition, since the ultrasonic vibration is applied while supplying the microbubble to the periphery of the substrate W, the microbubble can absorb the shock of the ultrasonic vibration, and the excessive shock to the substrate W can be reduced. For this reason, particles can be released from the substrate W while alleviating damage to the substrate W.

  In the substrate processing apparatus 3, part of the nitrogen gas is dissolved in pure water in the microbubble generator 33. For this reason, the charge of pure water can be reduced, and the pure water itself can be prevented from absorbing particles from each part of the pipe and the processing tank 10. Further, since nitrogen gas is dissolved in pure water, ultrasonic vibration can be efficiently propagated to the substrate W.

<4. Fourth Embodiment>
Next, a fourth embodiment of the present invention will be described. The fourth embodiment is also an embodiment when the present invention is applied to a single wafer processing apparatus. FIG. 14 is a longitudinal sectional view of the substrate processing apparatus 4 according to the fourth embodiment. The substrate processing apparatus 4 is different from the substrate processing apparatus 1 in the configuration of the microbubble generator 161 and the pump 162, and other parts are the same as the substrate processing apparatus 3 described above. For this reason, parts other than the microbubble generator 161 and the pump 162 are denoted by the same reference numerals as those in FIG. 11 in FIG.

  The microbubble generating unit 161 of the substrate processing apparatus 4 has the same configuration as the microbubble generating unit 71 of the second embodiment, and the degassing unit 161a, the gas dissolving unit 161b, and the heater 161c are arranged on the pipe 134. Have. These deaeration unit 161a, gas dissolution unit 161b, and heater 161c are electrically connected to the control unit 150. The gas dissolving part 161b is connected to a nitrogen gas supply source 132 via a pipe 135.

  The microbubble generator 161 generates microbubbles in the same manner as the microbubble generator 71 of the second embodiment. That is, the first supersaturated state is created by the pressure drop when pure water exits the gas dissolving part 161b, and the first microbubbles are generated. Further, the second supersaturated state is created by the rise in the temperature of pure water when passing through the heater 161c, and second microbubbles are generated.

  A unit 710 as shown in FIG. 9 can also be used for the deaeration unit 161a and the gas dissolution unit 161b, which are components of the microbubble generation unit 161.

  Although this substrate processing apparatus 4 is different from the third embodiment in the configuration of the microbubble generator 161 as described above, the substrate processing apparatus 4 can perform operations as shown in FIGS. 12 to 13 as in the third embodiment. . That is, pure water containing microbubbles and having ultrasonic vibrations can be discharged on the upper surface of the substrate W rotating on the base member.

  Therefore, this substrate processing apparatus 4 can also obtain the effect of releasing particles from the substrate W by the impact of ultrasonic vibration and removing the released particles by adsorbing them to the microbubbles. Moreover, the effect which softens the excessive impact by ultrasonic vibration by microbubble can also be acquired.

  Also in this substrate processing apparatus 4, a part of the nitrogen gas dissolved in the pure water in the gas dissolving part 161 b continues to be dissolved in the pure water without being generated as microbubbles. For this reason, as in the third embodiment, the effect of reducing the charge of pure water itself and the effect of improving the propagation efficiency of ultrasonic vibrations can be obtained.

<5. Other>
In each of the above-described embodiments, only the operation related to the particle removal process has been described for the operations of the substrate processing apparatuses 1 to 4. However, the substrate processing apparatus of the present invention is configured to perform other various operations. Also good.

  In each of the above embodiments, the case where the liquid supplied to the substrate W is pure water has been described, but the liquid supplied to the substrate W may be another liquid.

  In each of the above embodiments, the case where the gas dissolved in the liquid and the gas constituting the microbubble are both nitrogen gas has been described, but other gases such as carbon dioxide and ozone may be used. Good. Further, the gas dissolved in the liquid and the gas constituting the microbubbles may be different types of gases.

  In the first embodiment and the second embodiment described above, the case where the pure water overflowing to the outer tub is discharged to the drain line is described. However, microbubbles and particles are removed from the pure water overflowing to the outer tub. The configuration may be such that it is circulated again into the treatment tank 10. With such a configuration, it is possible to remove particles while saving the amount of pure water to be used.

It is the longitudinal cross-sectional view which cut | disconnected the substrate processing apparatus which concerns on 1st Embodiment by the plane parallel to a board | substrate. It is the longitudinal cross-sectional view which cut | disconnected the substrate processing apparatus which concerns on 1st Embodiment in the plane perpendicular | vertical to a board | substrate. It is the figure which showed the mode of operation | movement of the substrate processing apparatus which concerns on 1st Embodiment. It is the figure which showed the mode of operation | movement of the substrate processing apparatus which concerns on 1st Embodiment. It is the figure which showed the mode of operation | movement of the substrate processing apparatus which concerns on 1st Embodiment. It is the figure which showed the mode of operation | movement of the substrate processing apparatus which concerns on 1st Embodiment. It is the longitudinal cross-sectional view which cut | disconnected the substrate processing apparatus which concerns on 2nd Embodiment by the plane parallel to a board | substrate. It is the graph which showed the saturated dissolution density | concentration of the nitrogen gas with respect to a pure water. It is the figure which showed the unit which can be utilized as a deaeration part or a gas melt | dissolution part. It is the graph which showed the removal rate of the particle from a board | substrate. It is a longitudinal cross-sectional view of the substrate processing apparatus which concerns on 3rd Embodiment. It is the figure which showed the mode of operation | movement of the substrate processing apparatus which concerns on 3rd Embodiment. It is the figure which showed the mode of operation | movement of the substrate processing apparatus which concerns on 3rd Embodiment. It is a longitudinal cross-sectional view of the substrate processing apparatus which concerns on 4th Embodiment.

Explanation of symbols

1, 2, 3, 4 Substrate processing apparatus 10 Processing tank 11 Discharge unit 12 Outer tank 30, 130 Pure water supply system 33, 71, 133, 161 Micro bubble generating unit 33a, 133a Gas-liquid mixing pump 33b, 133b Swivel accelerator 33c , 133c Disperser 50 Ultrasonic generator 52, 122 Ultrasonic vibrator 60, 150 Control unit 71a, 161a Deaeration unit 71b, 161b Gas dissolution unit 71c, 161c Heater 120 Pure water discharge unit 710 Unit W substrate

Claims (10)

A substrate processing apparatus for processing a substrate with a liquid,
Holding means for holding the substrate;
Liquid supply means for supplying a liquid to the substrate held by the holding means;
The liquid supply means comprises
Gas dissolving means for dissolving a predetermined gas in the liquid;
A substrate processing apparatus comprising: microbubble generating means for generating microbubbles in the liquid. The substrate processing apparatus according to claim 1,
The micro-bubble generating means forms a gas-liquid two-layer flow with the liquid and a predetermined gas and shears the gas-liquid two-layer flow to generate a microbubble. The substrate processing apparatus according to claim 1,
The substrate processing apparatus characterized in that the microbubble generating means generates microbubbles by bubbling a part of the gas dissolved by the gas dissolving means by supersaturation. The substrate processing apparatus according to claim 3, wherein
The gas dissolving means pressurizes and dissolves a predetermined gas in the liquid,
The micro-bubble generating means includes means for generating a micro-bubble by supersaturating a part of the gas pressure-dissolved by the gas-dissolving means by a pressure drop after pressure-dissolving. apparatus. The substrate processing apparatus according to claim 3 or 4, wherein
The substrate processing apparatus, wherein the microbubble generating means includes means for supersaturating a part of the gas dissolved by the gas dissolving means to generate microbubbles. A particle removal method for removing particles from a substrate surface or liquid,
A first step of dissolving a predetermined gas in the liquid;
A second step of generating microbubbles in the liquid;
A third step of forming a flow of the liquid along the surface of the substrate;
A particle removal method comprising: The particle removal method according to claim 6,
In the second step, a gas-liquid two-layer flow is formed by the liquid and a predetermined gas, and the gas-liquid two-layer flow is sheared to generate microbubbles. The particle removal method according to claim 6,
In the second step, a part of the gas dissolved in the first step is bubbled by supersaturation to generate microbubbles. The particle removal method according to claim 8, wherein
In the first step, a predetermined gas is dissolved under pressure in the liquid,
In the second step, a part of the gas dissolved under pressure in the first step is supersaturated by a pressure drop after pressure dissolution to generate microbubbles. The particle removal method according to claim 8 or 9, wherein
In the second step, a part of the gas dissolved in the first step is supersaturated by heating to generate microbubbles.

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