JP2011121009A - Substrate treatment apparatus and substrate treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress damage to a substrate with respect to a substrate treatment apparatus and a substrate treatment method for applying ultrasonic vibration to a liquid film formed on the substrate surface. <P>SOLUTION: A liquid film LF1 of a HFE solution (a first treatment solution) is formed on a substrate surface Wf and further a liquid film LF2 of a DIW (a second treatment solution) is formed on the liquid film LF1 of the HFE solution. Thereafter, ultrasonic vibration is applied to the liquid film LF2. Accordingly, the impact waves generated in the liquid film LF2 by ultrasonic vibration application do not all reach the substrate surface Wf through the liquid film LF1 and some are reflected by the boundary face BF formed between both liquid films LF1 and LF2. Further, the impact waves passing the boundary face BF are dampened during the time of reaching the substrate surface Wf through the liquid film LF1. Consequently, the energy of the impact waves generated in the liquid film LF2 and applied to the substrate surface Wf by ultrasonic vibration is efficiently lowered. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

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), a substrate for optical disk, a substrate for magnetic disk, and a magneto-optical disk. The present invention relates to a substrate processing apparatus and a substrate processing method for ultrasonically cleaning a substrate for use.

  The manufacturing process of electronic components such as semiconductor devices and liquid crystal display devices includes a process step of forming a fine pattern by repeatedly performing processes such as film formation and etching on the surface of a substrate. Here, in order to perform fine processing satisfactorily, it is necessary to keep the substrate surface clean, and a cleaning process is performed on the substrate surface as necessary. Therefore, conventionally, in order to remove particles adhering to the substrate, for example, in the apparatuses described in Patent Documents 1 and 2, a liquid film of a treatment liquid such as deionized water is formed on the surface of the substrate and ultrasonic waves are applied to the liquid film. The substrate surface is cleaned by applying vibration.

Japanese Patent No. 3493492 (FIGS. 6 and 7) Japanese Patent Laying-Open No. 2001-87725 (FIG. 2)

  In the cleaning method described above, a shock wave is generated due to cavitation collapse generated in the liquid film of the treatment liquid due to the application of ultrasonic vibration, and the energy of this shock wave is used to effectively separate and remove particles from the substrate. ing. For this reason, if strong energy propagates as it is to the fine pattern on the substrate surface, the substrate surface may be damaged. In particular, when cavitation collapse occurs in the vicinity of the fine pattern in the liquid film of the processing solution, the distance until the shock wave reaches the fine pattern is short, and a shock wave having relatively large energy is given to the fine pattern. Here, if it is possible to control so that cavitation collapse does not occur in the vicinity of the substrate surface, the above damage can be reduced, but this is difficult with conventional ultrasonic cleaning technology, It sometimes caused damage.

  The present invention has been made in view of the above problems, and an object thereof is to reduce damage to a substrate in a substrate processing apparatus and a substrate processing method for applying ultrasonic vibration to a liquid film formed on a substrate surface.

  In order to achieve the above object, a substrate processing apparatus according to the present invention has a substrate holding means for holding a substrate and a first processing liquid supply for supplying a first processing liquid toward the surface of the substrate held by the substrate holding means. Means, a second processing liquid supply means for supplying a second processing liquid having a specific gravity smaller than that of the first processing liquid toward the substrate surface, and the first processing on the substrate surface by supplying the first processing liquid and the second processing. Ultrasonic wave application means for applying ultrasonic vibration to the liquid film of the second treatment liquid formed on the liquid film of the liquid is provided.

  In order to achieve the above object, the substrate processing method according to the present invention supplies the first processing liquid and the second processing liquid having a specific gravity smaller than that of the first processing liquid simultaneously or at different timings toward the surface of the substrate. Then, after forming a liquid film of the first processing liquid on the substrate surface and forming a liquid film of the second processing liquid on the liquid film of the first processing liquid, the liquid film of the second processing liquid is It is characterized by applying sonic vibration.

  In the invention thus configured (substrate processing apparatus and substrate processing method), the liquid film of the first processing liquid is formed on the substrate surface, and the liquid film of the second processing liquid is further formed on the liquid film of the first processing liquid. And has a double liquid film structure in which an interface exists between the two liquid films. Then, ultrasonic vibration is applied to the liquid film of the second processing liquid. By applying this ultrasonic vibration, cavitation occurs in the liquid film of the second processing liquid, and when it collapses, a shock wave is generated and incident on the liquid film of the second processing liquid through the interface. At this time, a part of the shock wave is reflected by the interface and the energy of the shock wave is attenuated. Furthermore, since the shock wave that has passed through the interface propagates through the liquid film of the first treatment liquid and reaches the substrate surface, the energy of the shock wave is attenuated during the propagation. Thus, due to the presence of the interface and the liquid film of the first processing liquid, the energy of the shock wave generated in the liquid film of the second processing liquid and applied to the substrate surface is lower than the ultrasonic vibration, and as a result, the substrate is damaged. Is reduced.

Here, the second treatment liquid can be made of a liquid in which cavitation due to ultrasonic vibration is more likely to occur than the first treatment liquid. In order to clean the substrate surface using ultrasonic vibration, it is necessary to generate cavitation in the liquid film of the second processing liquid. Further, when ultrasonic vibration is applied to the liquid film of the second processing liquid, the ultrasonic vibration is also propagated to the liquid film of the first processing liquid, but the first processing liquid is compared with the second processing liquid. Since cavitation hardly occurs, the following effects can be obtained. That is, if cavitation occurs frequently in the liquid film of the first processing liquid, a shock wave generated by the collapse of the cavitation is directly applied to the substrate surface. However, since cavitation is less likely to occur in the liquid film of the first processing liquid than in the liquid film of the second processing liquid, the frequency of occurrence of cavitation collapse in the liquid film of the first processing liquid is reduced. As a result, damage to the substrate surface can be effectively reduced. For example, when the cavitation coefficients of the first processing liquid and the second processing liquid supplied to the substrate surface are α1 and α2, respectively,
α1> α2
As described above, the above-described effects can be obtained with certainty.

  Further, in order to obtain the above-described double liquid film structure (liquid film of the first processing liquid-interface-liquid film of the second processing liquid), for example, on the substrate surface on which the liquid film of the first processing liquid is formed. Then, the second processing liquid may be supplied by the second processing liquid supply means to form the liquid film of the second processing liquid on the liquid film of the first processing liquid. When the first treatment liquid and the second treatment liquid are difficult to mix with each other, the specific gravity of the first treatment liquid with respect to the standard substance (usually 4 ° C. water) and the second treatment with respect to the standard substance You may utilize the difference with the specific gravity of a liquid. That is, since the specific gravity of the second processing liquid is smaller than that of the first processing liquid, the two processing liquids are supplied to the substrate surface, and then left for a predetermined time, so that the double liquid film structure (the liquid film-interface of the first processing liquid) -Liquid film of the second treatment liquid) is obtained.

  Further, in the present invention that forms a double liquid film structure, the height from the substrate surface to the liquid film of the second processing liquid can be changed by controlling the thickness of the liquid film of the first processing liquid, As a result, the balance between the damage to the substrate and the ultrasonic cleaning power can be optimized. That is, when the liquid film of the first processing liquid is made relatively thick by the liquid film thickness control means, the liquid film of the second processing liquid is separated from the substrate surface, and cavitation occurs at a position relatively far from the substrate surface. The energy generated at the time of collapse of the substrate and propagated to the substrate surface is reduced, and damage to the substrate surface can be greatly reduced. On the contrary, when the liquid film of the first processing liquid is relatively thin by the liquid film thickness control means, the liquid film of the second processing liquid approaches the substrate surface, and cavitation occurs at a position relatively close to the substrate surface. The energy generated when the cavitation collapses and propagates to the substrate surface is somewhat attenuated by the interface and the liquid film of the first treatment liquid, but sufficient energy is given to the substrate surface to enhance the ultrasonic cleaning effect. Can do.

  Further, for example, hydrofluoroether can be used as the first processing liquid, and deionized water can be used as the second processing liquid.

  Further, since the liquid film of the first treatment liquid is formed for reducing damage in addition to the second treatment liquid that imparts ultrasonic vibration as described above, the first treatment liquid is applied to the substrate surface after application of ultrasonic vibration. It is desirable to remove it reliably. Therefore, a cleaning unit may be further provided for supplying a third processing liquid different from the first processing liquid to the surface of the substrate to which ultrasonic vibration is applied from the ultrasonic wave application unit, and cleaning the substrate surface. For example, a mixed aqueous solution (SC1 solution) of ammonia water and hydrogen peroxide water may be used as the third treatment liquid.

  According to the present invention, the liquid film of the second processing liquid is formed on the liquid film of the first processing liquid formed on the substrate surface, and ultrasonic vibration is applied to the liquid film of the second processing liquid. Since it is configured to impart, damage to the substrate due to the addition of ultrasonic vibration can be effectively reduced.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the substrate processing apparatus concerning this invention. It is sectional drawing which shows the structure of the ultrasonic application head used with the substrate processing apparatus of FIG. It is a block diagram which shows the electric constitution of the substrate processing apparatus shown in FIG. It is a figure which shows typically the ultrasonic cleaning operation | movement performed with the substrate processing apparatus shown in FIG. It is a figure which shows 2nd Embodiment of the substrate processing apparatus concerning this invention. It is a figure which shows typically the ultrasonic cleaning operation | movement performed with the substrate processing apparatus shown in FIG.

  FIG. 1 is a diagram showing a first embodiment of a substrate processing apparatus according to the present invention. FIG. 2 is a cross-sectional view showing the configuration of an ultrasonic wave application head used in the substrate processing apparatus of FIG. 3 is a block diagram showing an electrical configuration of the substrate processing apparatus shown in FIG. This substrate processing 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 the first processing liquid and the second processing liquid are supplied to the substrate surface Wf on which the device pattern is formed to form a liquid film LF (= LF1 + LF2) having a double liquid film structure. This is an apparatus for ultrasonically cleaning the substrate W by applying ultrasonic vibration to the surface side liquid film (liquid film LF2 of the second processing liquid).

  The substrate processing apparatus includes a spin base 11 having a slightly larger planar size than the substrate W. A plurality of support pins 12 are arranged on the periphery of the upper surface of the spin base 11. Each support pin 12 comes into contact with the end of the substrate W, so that the substrate W is held in a substantially horizontal state with the substrate surface Wf of the substrate W facing upward. Thus, in this embodiment, the spin base 11 and the support pins 12 function as the “substrate holding means” of the present invention. The configuration for holding the substrate (substrate holding means) is not limited to this, and the substrate W may be held by an adsorption method such as a spin chuck.

  As shown in FIG. 1, a rotation shaft 31 is connected to the spin base 11. The rotating shaft 31 is connected to an output rotating shaft 34 of a motor 33 via a belt 32. And if the motor 33 act | operates based on the control signal from the control unit 2, the rotating shaft 31 will rotate with the motor drive. As a result, the substrate W held by the support pins 12 above the spin base 11 rotates around the rotation axis Pa together with the spin base 11.

  A first nozzle N1 for supplying the first processing liquid and the rinsing liquid to the surface Wf of the substrate W thus rotationally driven, and a second nozzle for supplying the second processing liquid to the surface Wf in a mist form. N2 is arranged above the spin base 11. In this embodiment, HFE (Hydrofluoroether) liquid is supplied as the first processing liquid, and DIW (deionized water) can be supplied as the second processing liquid and the rinsing liquid.

  That is, the HFE liquid supply unit 41 is connected to the first nozzle N1 via the opening / closing valve 42, and the DIW supply unit 43 is connected via the opening / closing valve 44. These on-off valves 42 and 44 are always closed, and the on-off valve 42 is opened in response to an opening command from the control unit 2 when a liquid film of HEF liquid is formed on the substrate W, as will be described later.

  As a result, the HFE liquid is pumped from the HFE liquid supply unit 41 to the first nozzle N1 via the opening / closing valve 42, and the HFE liquid is discharged from the first nozzle N1 toward the substrate surface Wf. On the other hand, as will be described later, the opening / closing valve 44 is opened in response to an opening command from the control unit 2 during the rinsing process. Thereby, DIW is pressure-fed from the DIW supply unit 43 to the first nozzle N1 via the opening / closing valve 44, and DIW is discharged from the first nozzle N1 toward the substrate surface Wf.

Note that as the “HFE liquid”, for example, HFE of the trade name Novec (registered trademark) series manufactured by Sumitomo 3M Limited can be used. Specifically, as HFE, for example, chemical formula: C ₄ F ₉ OCH ₃ ), chemical formula: C ₄ F ₉ OC ₂ H ₅ , chemical formula: C ₆ F ₁₃ OCH ₃ , chemical formula: C ₃ HF ₆ —CH (CH ₃₎ ) O—C ₃ HF ₆ , chemical formula: C ₂ HF ₄ OCH _{3 and the} like can be used. The density of these HFE liquids is 1430-1660 (kg / m ³ ), and the specific gravity with respect to water is greater than “1”. Therefore, the specific gravity of DIW used as the “second processing liquid” of the present invention is smaller than that of the HFE liquid used as the “first processing liquid” of the present invention. Thus, in this embodiment, the HFE liquid supply unit 41 and the DIW supply unit 43 correspond to the “first processing liquid supply unit” and the “second processing liquid supply unit” of the present invention, respectively.

  The DIW supply unit 43 is also connected to the second nozzle N2 via the opening / closing valve 45. The opening / closing valve 45 is always closed like the opening / closing valves 42, 44, and the opening / closing valve 45 is opened in response to an opening command from the control unit 2 when a DIW liquid film is formed on the substrate W as will be described later. To do. Thus, DIW is pressure-fed from the DIW supply unit 43 to the second nozzle N2 via the opening / closing valve 45, and mist-like DIW is discharged from the second nozzle N2 toward the substrate surface Wf.

  The upper end of the first nozzle N1 that discharges the first processing liquid (HFE liquid) and the rinsing liquid (DIW) is connected to the first nozzle drive mechanism 51 by a horizontal beam 46. The first nozzle drive mechanism 51 is configured in the same manner as a head drive mechanism 73 described later, and operates in response to a control signal from the control unit 2 to move the nozzle N1 up and down together with the horizontal beam 46. In addition, it is configured to reciprocate between a supply position (on the rotational axis Pa and above the spin base 11) and a retreat position (position away from the spin base 11 to the side). When discharging the first processing liquid (HFE liquid) and the rinsing liquid (DIW), the first nozzle N1 is moved from the retracted position to the supply position, and the height position command given from the control unit 2 is used. It is positioned at a height position corresponding to

  The other second nozzle N2 is connected to the second nozzle drive mechanism 52 by a horizontal beam 47, and is moved up and down integrally with the horizontal beam 47, and retracted from the supply position in the same manner as the first nozzle N1. It is reciprocated between positions. When the second processing liquid (mist-like DIW) is discharged, the second nozzle N2 is moved from the retracted position to the supply position, and the height corresponding to the height position command given from the control unit 2 is increased. It is positioned in the position.

  Further, in order to prevent the liquid (HFE liquid, DIW) discharged from the nozzles N1 and N2 from being scattered around the substrate W and the spin base 11, a splash prevention cup 61 is provided around the spin base 11. Yes. That is, when the cup raising / lowering driving mechanism 62 raises the cup 61 in accordance with a control signal from the control unit 2, the cup 61 laterally moves the substrate W held by the spin base 11 and the support pins 12 as shown in FIG. The HFE liquid and DIW that surround the position and scatter from the spin base 11 and the substrate W can be collected. On the other hand, a transfer unit (not shown) places an unprocessed substrate W on the support pins 12 on the spin base 11, receives a processed substrate W from the support pins 12, and an ultrasonic wave application unit to be described next When the seventh head 71 is moved between the vibration applying position and the retracted position, the cup raising / lowering driving mechanism 62 drives the cup 61 downward in accordance with a control signal from the control unit 2.

  FIG. 2 is a cross-sectional view showing the configuration of the ultrasonic wave application head. The ultrasonic wave application unit 7 includes an ultrasonic wave application head 71, an arm member 72 that holds the ultrasonic wave application head 71, and a head drive mechanism 73 that moves the ultrasonic wave application head 71.

  In the ultrasonic wave imparting head 71, a vibration plate 712 is attached to a bottom side opening of a main body portion 711 made of a fluororesin such as Teflon tetrafluoride (registered trademark). The diaphragm 712 has a disk shape in plan view, and the bottom surface thereof is a vibration surface VF. A vibrator 713 is attached to the upper surface of the diaphragm 712. Then, when a pulse signal is output from the ultrasonic oscillator 714 to the vibrator 713 based on the control signal from the control unit 2, the vibrator 713 vibrates ultrasonically.

  The ultrasonic wave application head 71 is held at one end of the arm member 72. A head driving mechanism 73 is connected to the other end of the arm member 72. The head drive mechanism 73 has a rotary motor 731 as shown in FIG. The rotary shaft 732 of the rotary motor 731 is connected to the other end of the arm member 72. When the rotary motor 731 is actuated in response to a control signal from the control unit 2, the arm member 72 swings around the rotation center Pb. The ultrasonic wave application head 71 is moved to reciprocate between the vibration application position and the retracted position.

  The elevating base 734 on which the rotation motor 731 is mounted is slidably fitted to an upright guide 735 and is screwed to a ball screw 736 provided side by side with the guide 735. The ball screw 736 is linked to the rotating shaft of the lifting motor 737. The lifting motor 737 operates in response to a control signal from the control unit 2 and rotates the ball screw 736 to move the head 71 up and down. Thus, the head drive mechanism 73 is a mechanism for positioning the ultrasonic wave application head 71 at the vibration application position by moving it up and down and reciprocating.

  Further, when the ultrasonic wave application head 71 is positioned at the vibration application position by the head drive mechanism 73, the distance between the vibration surface VF and the substrate surface Wf, that is, the substrate facing distance, is performed with high accuracy by drive control of the lifting motor 737. . When the control unit 2 operates the ultrasonic wave application head 71 in the liquid contact state, ultrasonic vibration is applied to the liquid film LF. In the present embodiment, as will be described later, a liquid film LF (= LF1 + LF2) having a double liquid film structure is formed, and the vibrating surface VF is configured to come into contact with the liquid film LF2 on the surface layer side. .

  The control unit 2 that controls the entire apparatus mainly includes a CPU (Central Processing Unit) 21, a RAM (Random Access Memory) 22, a ROM (Read Only Memory) 23, a motor 33, an HFE liquid supply unit 41, and the like. And a drive control unit 24 for controlling the driving of the motor. Among these, the ROM 23 is a so-called nonvolatile storage unit, and stores a program for controlling each unit of the apparatus. Then, when the CPU 21 controls each part of the apparatus according to the program stored in the ROM 23, the apparatus executes a substrate cleaning operation described below.

  In this substrate processing apparatus, an unprocessed substrate W is transported onto the support pins 12 by a transport unit (not shown) and held on the support pins 12. Then, after the transfer unit is retracted from the substrate processing apparatus, the CPU 21 of the control unit 2 controls each part of the apparatus to perform ultrasonic cleaning. At this time, the first nozzle N1, the second nozzle N2, and the ultrasonic wave application head 71 are positioned at the retreat positions that are separated from the spin base 11 in the horizontal direction.

  First, the rotation of the substrate W is started. Subsequently, after the first nozzle N1 is moved from the retracted position to the supply position (on the rotational axis Pa and above the spin base 11), the first nozzle N1 is moved from the first nozzle N1 to the HFE as shown in FIG. The liquid is discharged and supplied to the substrate surface Wf. As a result, the liquid film LF1 of the HFE liquid is formed on the substrate surface Wf (HFE liquid film forming operation). Then, the film thickness of the liquid film LF1 is adjusted with high accuracy by adjusting the rotation speed of the substrate W ((b) in the figure).

  For example, the liquid film LF1 having a thickness TH (see FIG. 2) corresponding to the rotation speed can be formed on the substrate surface Wf by setting the rotation speed of the substrate W to a higher rotation speed than that at the time of liquid film formation, for example, 500 rpm. it can. When the motor 33 is operated in accordance with a rotation speed command related to the rotation speed of the substrate W from the control unit 2 to change the rotation speed of the substrate W, the thickness TH of the liquid film LF1 of the HFE liquid depends on the rotation speed. Adjusted to the desired value. Thus, in the present embodiment, the motor 33 functions as the “liquid film thickness control means” of the present invention. The first nozzle N1 is moved to the retracted position after the supply of the HFE liquid to the substrate surface Wf is completed.

  After the liquid film LF1 of the HFE liquid is thus formed, the rotation speed of the substrate W is reduced to, for example, about 10 rpm. Further, after the second nozzle N2 has moved from the retracted position to the supply position (on the rotational axis Pa and above the spin base 11), the DIW is mist from the second nozzle N2 as shown in FIG. Are discharged toward the substrate surface Wf. Thus, a DIW liquid film LF2 is formed on the HFE liquid film LF1 on the substrate surface Wf (DIW film forming operation). As a result, a double liquid film structure (HFE liquid film LF1-interface BF-DIW liquid film LF2) is obtained. In addition, since the HFE liquid and DIW are difficult to mix with each other and the specific gravity of DIW is smaller than that of the HFE liquid, the above-mentioned double liquid film structure is stable, and the addition of ultrasonic vibration described below is added. Sometimes the double liquid film structure is stably maintained. The second nozzle N2 is moved to the retracted position after the formation of the double liquid film structure is completed.

  Then, the rotational speed of the substrate W is increased as compared with the formation of the double liquid film structure, and the ultrasonic wave application head 71 is moved from the retracted position to the vibration application position and positioned. As a result, the vibration surface VF comes into contact with the liquid film LF2. Subsequently, a pulse signal is output from the ultrasonic oscillator 714 to the vibrator 713, and the vibrator 713 vibrates ultrasonically ((d) in the figure). As a result, ultrasonic vibration is applied to the liquid film LF2, cavitation occurs and collapses in the liquid film LF2, and a shock wave is generated. A part of this shock wave is reflected at the interface BF between the liquid films LF1 and LF2. On the other hand, the shock wave that has passed through the interface BF passes through the liquid film LF1 and is propagated to the substrate surface Wf. Due to the energy of the shock wave, deposits such as particles are detached from the substrate surface Wf and released to the liquid film LF.

  After applying this ultrasonic wave, the ultrasonic vibration is stopped. In addition, the first nozzle N1 is moved again from the retracted position to the supply position as the ultrasonic wave application head 71 is moved to the retracted position, and as shown in FIG. DIW) is discharged, and the substrate surface Wf is rinsed. Thereby, the deposits released from the substrate surface Wf due to the application of ultrasonic vibration are removed from the substrate surface Wf together with the liquid film LF (LF1 + LF2).

  When the rinsing process is completed in this way, the rotational speed of the substrate W is increased and centrifugal force is applied to the cleaning liquid remaining on the substrate W to remove the rinsing liquid from the substrate W and dry it (FIG. 4F: spin). Dry). When a series of processing is completed, the substrate W processed by the transport unit is unloaded from the substrate processing apparatus.

  As described above, in the first embodiment of the present invention, the liquid film LF1 of the HFE liquid (first processing liquid) is formed on the substrate surface Wf, and DIW (second processing liquid) is further formed on the liquid film LF1 of the HFE liquid. ) Liquid film LF2 is formed, and ultrasonic cleaning is executed by applying ultrasonic vibration to the liquid film LF2. Therefore, not all of the shock waves generated in the liquid film LF2 by the application of the ultrasonic vibration reach the substrate surface Wf, but a part thereof is reflected by the interface BF formed between the two liquid films LF1 and LF2. . In addition, the shock wave that has passed through the interface BF is attenuated before it passes through the liquid film LF1 and reaches the substrate surface Wf. Therefore, the energy of the shock wave generated in the liquid film LF2 by ultrasonic vibration and applied to the substrate surface Wf is effectively reduced, and damage to the substrate surface Wf can be suppressed.

In the first embodiment, ultrasonic vibration is applied in a state where the liquid films LF1 and LF2 are formed on the substrate surface Wf. The cavitation coefficients of the HFE liquid and DIW at this time are α1, α2, and When
α1> α2
In other words, DIW is a liquid that is more susceptible to cavitation due to ultrasonic vibration than HFE liquid. Therefore, by applying ultrasonic vibration, cavitation is generated in the liquid film of DIW (second processing liquid), and a shock wave necessary for ultrasonic cleaning can be formed (however, in this embodiment, as described above) Thus, the energy of the shock wave generated in the liquid film LF2 is attenuated by the liquid film LF1 of the interface BF and the HFE liquid and adjusted to an appropriate energy).

  Moreover, since the cavitation occurrence frequency of the HFE liquid in the liquid film LF1 is lower than that in the liquid film LF2, as described above, the following operational effects can be obtained. That is, since a shock wave generated by the occurrence and collapse of cavitation in the liquid film LF1 directly formed on the substrate surface Wf is directly applied to the substrate surface Wf, when cavitation occurs frequently in the liquid film LF1, The substrate surface Wf is greatly damaged. However, in the present embodiment, by using the HFE liquid as the “first processing liquid” of the present invention, the occurrence of cavitation in the liquid film LF1 is suppressed, and the generation of shock waves in the liquid film LF1 is reduced. As a result, damage to the substrate surface Wf can be effectively reduced.

  Further, in order to configure the above-described double liquid film structure (liquid film LF1-interface BF-liquid film LF2), as shown in FIG. 4C, the substrate surface on which the liquid film LF1 of the HFE liquid is formed. Since the liquid film LF2 is formed by supplying DIW to Wf in a mist form, a double liquid film structure can be stably formed. Furthermore, in the first embodiment, since the substrate W is rotated simultaneously with the DIW supply, the liquid film LF2 and the interface BF can be formed flatly and uniformly. As a result, the shock wave can be uniformly reduced by the interface BF, and the in-plane uniformity of ultrasonic cleaning can be improved.

  In the first embodiment, the thickness of the liquid film LF1 of the HFE liquid is adjusted by changing the rotation speed of the substrate W, and the cavitation substrate generated in the liquid film LF2 of the DIW (second processing liquid). The height from the surface Wf can be changed, and the attenuation amount of the shock wave when passing through the liquid film LF1 can be controlled by adjusting the thickness. That is, by setting the rotation speed of the substrate W by the motor 33 to be relatively low, a relatively thick liquid film LF1 is formed, the DIW liquid film LF2 is separated from the substrate surface Wf, and cavitation is relatively far from the substrate surface Wf. Occurs at position. As the cavitation moves away from the substrate surface Wf in this way, the energy that is generated when the cavitation collapses and propagates to the substrate surface Wf is reduced, and damage to the substrate surface Wf can be greatly reduced. Conversely, when the rotation speed of the substrate W is set to a relatively high speed, the liquid film LF1 becomes thin and cavitation occurs in the liquid film LF2 of DIW at a position relatively close to the substrate surface Wf. , The energy generated when the cavitation is collapsed and propagated to the substrate surface Wf is increased, and the energy sufficient for cleaning the substrate is sufficiently attenuated by the interface BF and the liquid film LF1 of the HFE liquid. The ultrasonic cleaning effect can be enhanced. As described above, in the first embodiment, the motor 33 can function as the “liquid film thickness control unit” of the present invention to optimize the balance between the damage to the substrate W and the ultrasonic cleaning power.

  Furthermore, in the first embodiment, after forming the liquid film LF having the double liquid film structure, since the ultrasonic vibration is applied by increasing the rotation speed of the substrate W, the ultrasonic wave can be suppressed by suppressing the disturbance of the interface BF. In-plane uniformity of cleaning can be further enhanced.

  FIG. 5 is a view showing a second embodiment of the substrate processing apparatus according to the present invention. FIG. 6 is a diagram schematically showing an ultrasonic cleaning operation executed by the substrate processing apparatus shown in FIG. The second embodiment is greatly different from the first embodiment in the supply mode of the HFE liquid (first processing liquid) and DIW (second processing liquid) and the formation mode of the double liquid film structure. The configuration and operation are basically the same as those in the first embodiment. Accordingly, the following description will focus on the differences, and the same components will be assigned the same reference numerals and description thereof will be omitted.

  In the second embodiment, without using the second nozzle N2, the HFE liquid is used as the first processing liquid, DIW is used as the second processing liquid, and DIW is used as the rinsing liquid from the first nozzle N1 as follows. A liquid film LF (= LF1 + LF2) having a double liquid film structure is formed by discharging toward the substrate surface Wf. That is, when an unprocessed substrate W is transported onto the support pins 12 by a transport unit (not shown) and held on the support pins 12, the first nozzle N1 is moved from the retracted position to the supply position (rotation shaft) as the substrate W rotates. And moved to a position above the spin base 11 and above the spin base 11. Then, the opening and closing valves 42 and 44 are opened, and the HFE liquid and DIW are simultaneously pumped to the first nozzle N1, and the liquid containing the HFE liquid and DIW is discharged from the first nozzle N1 toward the substrate surface Wf (FIG. 6 (a)). In the second embodiment, the HFE liquid supply unit 41, which is a means for supplying the HFE liquid (first processing liquid), can adjust the supply flow rate according to a command from the control unit 2, and the first nozzle N1 as described above. It is possible to adjust the weight percent of the HFE liquid in the liquid discharged from the liquid.

  When the HFE liquid and DIW are simultaneously supplied to the substrate surface Wf in this way, the rotation speed of the substrate W is reduced to, for example, about 10 rpm, and the HFE liquid and DIW remain on the substrate surface Wf in a paddle shape. At this time, since the HFE liquid and DIW are difficult to mix with each other and the specific gravity of DIW is smaller than that of the HFE liquid, a double liquid film structure (HFE liquid) is formed during paddle formation as shown in FIG. Liquid film LF1--liquid film LF2) of interface BF-DIW is obtained.

  In addition, after the formation of the liquid film LF (= LF1 + LF2) having the double liquid film structure and the completion of the movement of the first nozzle N1 to the retracted position, the ultrasonic wave application head 71 vibrates from the retracted position as in the first embodiment. The liquid film LF2 is moved to the application position and positioned, and ultrasonic vibration is applied to the liquid film LF2 (FIG. (C)), and rinse treatment (FIG. (D)) and spin drying (FIG. (E)) are further performed. Executed.

  As described above, also in the second embodiment of the present invention, the liquid film LF1 of the HFE liquid (first processing liquid) is formed on the substrate surface Wf, and DIW (second processing) is further formed on the liquid film LF1 of the HFE liquid. Since the liquid film LF2 is formed, and ultrasonic vibration is performed by applying ultrasonic vibration to the liquid film LF2, the same effects as the first embodiment can be obtained. In addition, since the HFE liquid and DIW are discharged simultaneously, the second nozzle N2 is not necessary, and the ultrasonic cleaning process can be performed with a smaller number of steps than in the first embodiment, thereby increasing the throughput. .

  In the second embodiment, the HFE liquid supply flow rate from the HFE liquid supply unit 41 is adjusted to adjust the weight% of the HFE liquid in the liquid discharged from the first nozzle N1, and thus the substrate surface Wf. It is possible to adjust the thickness TH of the liquid film LF1 of the HFE liquid formed on the top. Therefore, by adjusting the thickness, the height of the cavitation generated in the liquid film LF2 of DIW (second processing liquid) from the substrate surface Wf is changed to control the amount of shock wave attenuation when passing through the liquid film LF1. Can do. That is, when the weight% of the HFE liquid in the liquid discharged from the first nozzle N1 is increased by the HFE liquid supply flow rate by the HFE liquid supply unit 41, a relatively thick liquid film LF1 is formed, and the DIW liquid film LF2 is formed. Cavitation is generated at a position far from the substrate surface Wf and relatively far from the substrate surface Wf.

  As the cavitation moves away from the substrate surface Wf in this way, the energy that is generated when the cavitation collapses and propagates to the substrate surface Wf is reduced, and damage to the substrate surface Wf can be greatly reduced. On the contrary, when the HFE liquid supply flow rate by the HFE liquid supply unit 41 is suppressed to reduce the weight% of the HFE liquid, the liquid film LF1 becomes thin, and the liquid film LF2 having a cavitation of DIW at a position relatively close to the substrate surface Wf. Therefore, the energy that is generated when the cavitation collapses and propagates to the substrate surface Wf increases and the possibility of damage to the substrate surface Wf increases, but the ultrasonic cleaning effect can be enhanced. As described above, in the second embodiment, the HFE liquid supply unit 41 functions not only as the “first processing liquid supply unit” of the present invention but also as the “liquid film thickness control unit”, and the substrate W is damaged and superfluous. The balance of sonic cleaning power can be optimized.

  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 second embodiment, the weight of the HFE liquid in the liquid discharged from the first nozzle N1 by controlling the DIW supply flow rate while adjusting the HFE liquid supply flow rate or keeping the HFE liquid supply flow rate constant. % May be adjusted. In this case, the DIW supply unit 43 functions not only as the “second liquid supply unit” of the present invention but also as the “liquid film thickness control unit” to optimize the balance between the damage to the substrate W and the ultrasonic cleaning power. can do.

  In each of the above embodiments, the rinsing process is performed after applying the ultrasonic vibration. However, the SC1 solution (mixing of ammonia water and hydrogen peroxide solution) is applied after the ultrasonic vibration is applied and before the rinsing process. A third treatment liquid used for substrate cleaning such as an aqueous solution may be supplied to the substrate surface Wf to remove particles with weak adhesion. In this way, by using a cleaning chemical such as the SC1 solution, organic contamination of the substrate surface Wf by the HFE liquid can be removed.

  In each of the above embodiments, the HFE liquid is used as the first processing liquid, but a processing liquid having a specific gravity higher than that of the second processing liquid, for example, dimethyl sulfoxide (DMSO) can be used.

  In each of the above embodiments, the HFE liquid and DIW are discharged from the first nozzle N1, but the HFE liquid and DIW may be discharged from different nozzles.

  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 ultrasonically cleaning the entire surface of a substrate including the substrate.

7 ... Ultrasonic application unit (Ultrasonic application means)
11 ... Spin base (substrate holding means)
12 ... Support pin (substrate holding means)
41... HFE liquid supply unit (first processing liquid supply means)
43 ... DIW supply section (second processing liquid supply means)
71 ... Ultrasonic wave application head (ultrasonic wave application means)
BF ... Interface LF ... Liquid film LF1 ... Liquid film (of the first treatment liquid) LF2 ... Liquid film (of the second treatment liquid) W ... Substrate Wf ... Substrate surface

Claims (10)

Substrate holding means for holding the substrate;
First processing liquid supply means for supplying a first processing liquid toward the surface of the substrate held by the substrate holding means;
Second processing liquid supply means for supplying a second processing liquid having a specific gravity smaller than that of the first processing liquid toward the substrate surface;
Ultrasonic wave is applied to the liquid film of the second processing liquid formed on the liquid film of the first processing liquid on the substrate surface by the supply of the first processing liquid and the second processing. A substrate processing apparatus comprising a sound wave applying unit.   The substrate processing apparatus according to claim 1, wherein the second processing liquid is a liquid in which cavitation due to ultrasonic vibration is more likely to occur than the first processing liquid. When the cavitation coefficients of the first treatment liquid and the second treatment liquid supplied to the substrate surface are α1 and α2, respectively.
α1> α2
The substrate processing apparatus according to claim 2, wherein:   The second processing liquid supply means supplies the second processing liquid to the substrate surface on which the liquid film of the first processing liquid is formed, and the second processing liquid is supplied onto the liquid film of the first processing liquid. The substrate processing apparatus according to claim 1, wherein a liquid film is formed. The first treatment liquid and the second treatment liquid are liquids that are difficult to mix with each other, and are left for a predetermined time after being supplied to the substrate surface,
4. The liquid film of the first processing liquid is formed on the substrate surface, and the liquid film of the second processing liquid is formed on the liquid film of the first processing liquid. 5. The substrate processing apparatus according to item. A liquid film thickness control means for controlling the thickness of the liquid film of the first treatment liquid;
6. The liquid film thickness control means changes the height from the substrate surface to the liquid film of the second processing liquid to control energy generated when the cavitation collapses and propagating to the substrate surface. The substrate processing apparatus as described in any one of these.   The substrate processing apparatus according to claim 1, wherein the first processing liquid is hydrofluoroether, and the second processing liquid is deionized water.   The cleaning apparatus according to claim 1, further comprising a cleaning unit configured to supply a third processing liquid different from the first processing liquid to the surface of the substrate to which ultrasonic vibration is applied from the ultrasonic wave applying unit, to clean the substrate surface. The substrate processing apparatus as described in any one of Claims.   The substrate processing apparatus according to claim 8, wherein the third processing liquid is a mixed aqueous solution of ammonia water and hydrogen peroxide water.   A first treatment liquid and a second treatment liquid having a specific gravity smaller than that of the first treatment liquid are supplied simultaneously or at different timings toward the surface of the substrate, and a liquid film of the first treatment liquid is formed on the substrate surface. And forming a liquid film of the second processing liquid on the liquid film of the first processing liquid, and then applying ultrasonic vibration to the liquid film of the second processing liquid. Method.

Images