JP5605207B2 - Cleaning device and cleaning method - Google Patents

Description

  The present invention relates to an ultrasonic cleaning device and a cleaning method.

  In the manufacturing process of a semiconductor element, a semiconductor wafer (hereinafter simply referred to as a wafer) is cleaned in each process. Conventionally, this wafer cleaning has been performed by dip-type cleaning in which a plurality of wafers are immersed in a large immersion tank at the same time. However, in recent years, with the increase in wafer size, single-wafer type ultrasonic waves have been used. Spin cleaning (hereinafter simply referred to as spin cleaning) is becoming mainstream. The reason why spin cleaning is used is that the surface of a large-diameter wafer can be cleaned uniformly, less re-deposition of contaminants removed by cleaning, and the amount of cleaning liquid and rinsing water used can be reduced. It is because it is advantageous compared with.

  In the spin cleaning method, the cleaning liquid is discharged from the ultrasonic nozzle onto the wafer surface while rotating the wafer in the cleaning chamber, and at the same time, the ultrasonic vibrator built in the ultrasonic nozzle is oscillated to pass the cleaning liquid through the cleaning liquid. The wafer surface is cleaned using the vibration energy of ultrasonic waves. The cleaning liquid discharged on the wafer surface moves in the outer peripheral direction by the centrifugal force accompanying the rotation of the wafer together with the contaminants floating out by the ultrasonic cleaning, and flows out from the outer peripheral edge of the wafer into the cleaning chamber. For this reason, this is the reason why contaminants are less likely to reattach to the wafer.

  By the way, in recent years, the miniaturization of the wiring of the semiconductor element has progressed, and the number of processes for cleaning a wafer on which a fine pattern is formed is increasing. For example, for the purpose of lowering the value of relative dielectric constant, the pattern width is smaller than the interlayer insulating film made of porous silica (porous silica) uniformly distributed inside the fine pores called pores. A fine pattern having a thickness of less than 100 nm is formed. When the above-described spin cleaning is used for such a wafer, the pattern formed on the wafer surface may be destroyed due to excessively high ultrasonic intensity. In order to avoid such pattern destruction, it is necessary to reduce the ultrasonic energy irradiated per unit area of the wafer surface in accordance with the structural strength of the pattern formed on the wafer surface. For this reason, the output of the ultrasonic oscillator for driving the ultrasonic transducer is adjusted according to the structure of the formed pattern, but the adjustment range is limited and cannot be sufficiently dealt with. This is because the ultrasonic vibrator has a specific vibration condition determined by the shape and structure, and if the drive output falls below a certain lower limit, stable vibration cannot be obtained and the vibration stops.

  In order to solve the problem that the adjustment range of the ultrasonic output is limited, there is known a method in which a vibrating body is provided in an ultrasonic vibrator and ultrasonic waves are irradiated onto the wafer surface via the vibrating body. The vibrating body has a wider ultrasonic irradiation surface than the above-described ultrasonic nozzle and serves to disperse the ultrasonic output. The vibration of the ultrasonic irradiation surface is determined by the materials and shapes of the ultrasonic vibrator and the vibrating body, and these can be predicted by simulation. Therefore, a vibrating body corresponding to the required ultrasonic output may be designed. Therefore, cleaning can be performed while suppressing pattern destruction by using a vibrating body corresponding to the pattern formed on the wafer.

JP 2005-181394 A JP 2003-31540 A

  In spin cleaning with a vibrating body, the ultrasonic irradiation surface of the vibrating body is held at a height of about 1 mm from the surface of the rotating wafer, and this gap (gap between the wafer surface and the ultrasonic irradiation surface) Then, ultrasonic waves are applied while discharging the cleaning liquid from the cleaning liquid nozzle. In order to irradiate the entire wafer with ultrasonic waves, the entire surface of the wafer is scanned by reciprocating between the outer peripheral portion and the central portion of the rotating wafer. Since the linear velocity is different (the linear velocity at the outer peripheral portion is larger than the linear velocity at the central portion), the ultrasonic energy received by the wafer becomes larger at the central portion. Accordingly, a phenomenon occurs in which the cleaning is completed earlier at the center of the wafer, and the cleaning is completed later at the outer peripheral portion. Considering the finished cleaning of the entire wafer, the cleaning must be continued until the cleaning of the outer peripheral portion is completed. For this reason, even after the cleaning is completed in the central portion, excessive ultrasonic energy continues to be irradiated, and there is a case where the pattern is broken near the center of rotation. In order to prevent this pattern destruction, if the ultrasonic output is set in accordance with the central part, the ultrasonic energy is insufficient at the outer peripheral part and sufficient cleaning is not performed.

  The problem of different ultrasonic energy applied at different peripheral speeds depending on the position of the wafer in the radial direction can be avoided by reducing the number of rotations of the wafer when cleaning the outer periphery of the wafer. However, by changing the rotation speed, the film thickness of the cleaning liquid changes due to centrifugal force, and there is a problem that there may occur a state where the surface between the ultrasonic irradiation surface of the vibrating body and the wafer surface is not filled with the cleaning liquid. come. That is, when a vibrating body is used, it is necessary to rotate the wafer at a constant speed.

  In view of such problems, an object of the present invention is to provide a cleaning apparatus and a cleaning method that perform cleaning by irradiating the entire wafer with ultrasonic energy having a uniform density in spin cleaning using a vibrating body.

  According to one aspect of the invention, a cleaning device of the present invention includes an ultrasonic vibrator that generates ultrasonic waves, and a vibrating body that has a flat ultrasonic irradiation surface that is fixed to the ultrasonic vibrator and irradiates the cleaning liquid with ultrasonic waves. A vibrating body unit, an irradiation surface angle control unit that rotates the vibrating body unit to change the angle of the ultrasonic irradiation surface around the direction intersecting the ultrasonic irradiation surface, and holds the substrate to be cleaned. Between the ultrasonic rotating surface and the cleaning surface, the rotating substrate rotating unit, the vibrating body moving mechanism for moving the vibrating body unit while keeping the ultrasonic irradiation surface of the vibrating body facing the cleaning surface of the substrate and maintaining a certain interval And a cleaning liquid supply unit that supplies the cleaning liquid.

  According to another aspect of the invention, the cleaning method of the present invention is a flat ultrasonic irradiation of a vibrating body fixed to an ultrasonic transducer by rotating the substrate while holding the substrate with the cleaning surface facing upward. Hold the surface facing the cleaning surface at a certain interval, move the vibrator in the radial direction of the substrate while filling the cleaning liquid in that interval, and with the movement, the angle of the ultrasonic irradiation surface intersects the cleaning surface as the axis A cleaning method of irradiating ultrasonic waves while changing is provided.

  When moving a vibrating body with a flat ultrasonic irradiation surface on the substrate, the angle of the ultrasonic irradiation surface is changed with the movement, so the angle can be changed according to the linear velocity depending on the position on the substrate. It is possible to provide a cleaning apparatus and a cleaning method capable of irradiating the entire wafer with ultrasonic energy having a uniform density.

This is an example of spin cleaning using an ultrasonic nozzle. This is an example of spin cleaning using a vibrator. It is an example of the linear velocity in the position on the wafer of a vibrating body. It is a connection example of a vibrating body unit and a servo motor. It is an example of arrangement | positioning of the vibrating body unit at the time of ultrasonic irradiation. It is an example of a change in the direction (angle) of the ultrasonic irradiation surface. It is a structural example (during wafer exchange) of a vibrating body moving mechanism. It is a structural example (during washing | cleaning) of a vibrating body moving mechanism. It is a structural example of a washing | cleaning apparatus.

  First, a general spin cleaning method will be described. FIG. 1 shows an example of spin cleaning using an ultrasonic nozzle, in which an ultrasonic vibrator is built in the ultrasonic nozzle 30 and the cleaning liquid 20 can be discharged from the tip of the ultrasonic nozzle 30 together. Yes. In the cleaning method, the wafer 10 as a substrate is rotated while being held in the horizontal direction (the circular arrow indicates the rotation direction of the wafer 10), and the cleaning liquid is discharged while the ultrasonic nozzle 30 is slightly lifted from the surface of the wafer 10. Then, the ultrasonic vibrator is operated to irradiate ultrasonic waves. At this time, the ultrasonic nozzle 30 is reciprocated in the radial direction of the wafer 10 by the arm 40 (a linear arrow indicates the direction of reciprocating motion), and the entire surface of the wafer 10 is irradiated with ultrasonic waves for cleaning.

  2A and 2B are diagrams for explaining a spin cleaning method using a vibrating body. FIG. 2A is a diagram schematically showing a main part, and FIG. 2B is a diagram of an ultrasonic irradiation unit. It is a partial enlarged view. Ultrasonic irradiation is performed by the vibrator 51 fixed to the ultrasonic vibrator 50. The vibrating body 51 shown here is made of ceramics and has a triangular prism shape, and one surface 51 a of the triangular prism is fixed to the ultrasonic transducer 50. The surface of the triangular prism facing the wafer 10 is an ultrasonic irradiation surface 51b, and ultrasonic waves are irradiated from this surface at a slight distance from the cleaning surface of the wafer 10. The cleaning liquid 20 is supplied from the cleaning liquid supply nozzle 60 so that the cleaning liquid 20 is filled between the ultrasonic irradiation surface 51 b and the wafer 10. When the ultrasonic transducer 50 is driven in this state, the generated ultrasonic wave propagates through the vibrating body 51, is transmitted from the ultrasonic irradiation surface 51 b to the cleaning liquid 20, and reaches the surface of the wafer 10. Here, although the material of the vibrating body 51 is ceramic and the shape is a triangular prism, various materials and shapes can be used.

  The vibrator 51 moves on the surface of the wafer 10 at a constant speed in the radial direction of the wafer 10 in the same manner as in the method using the ultrasonic nozzle (the straight arrow in FIG. 2A). Depending on the linear velocity. FIG. 3 is a diagram illustrating linear velocities at positions P1, P2, and P3 where the ultrasonic irradiation surface 51b of the vibrating body 51 is at distances r1, r2, and r3 from the center of the wafer 10. In FIG. The linear velocities at the positions P1, P2, and P3 are r1 * ω, r2 * ω, and r3 * ω, respectively, where ω is the angular velocity, and these have a relationship of r1 * ω <r2 * ω <r3 * ω. That is, the linear velocity at the position on the wafer 10 decreases as the distance from the center of rotation decreases, and increases as the distance from the rotation center increases (the linear velocity at the center of rotation becomes zero). Therefore, the intensity of the ultrasonic energy received by each position (P1, P2, P3) of the wafer 10 is P1> P2> P3, which is suitable for cleaning the outer peripheral portion (the portion at the position P3 in FIG. 3) as described above. If the ultrasonic output is set, a large amount of ultrasonic energy is applied to the central portion (portion P1 in FIG. 3), which causes pattern destruction.

  An embodiment of the present invention invented based on the above problems will be described. FIG. 4 is a diagram illustrating an example of a structure in which the vibrating body unit 100 serving as a point of the present invention and the irradiation surface angle control unit 130 that changes the rotation angle of the vibrating body unit 100 are connected. The vibrating body unit 100 includes an ultrasonic vibrator 120 and a vibrating body 110, and one surface of the vibrating body 110 is fixed to the ultrasonic vibrator 120. The vibrating body unit 100 is connected to a rotation shaft included in the irradiation surface angle control unit 130. The irradiation surface angle control unit 130 is further fixed to a support arm 140, and the support arm 140 vibrates to reciprocate on the wafer described later. It is fixed to the body movement mechanism. Although details will be described later, the vibrating body 110 fixed to the ultrasonic vibrator 120 reciprocates in the radial direction on the wafer by the vibrating body moving mechanism and is rotated by the irradiation surface angle control unit 130 to change the angle. Next, each component shown in FIG. 4 will be described.

  First, the vibrating body 110 is an elliptical cylinder, and the lower tip surface (elliptical surface) is an ultrasonic irradiation surface 111 that irradiates the wafer with ultrasonic waves (the lower elliptical shape in FIG. The shape of the sound wave irradiation surface 111 is shown). The ratio of the length of the minor axis to the major axis formed by the ellipsoid is 1: 4. The shape of the ultrasonic irradiation surface 111 does not necessarily need to be an ellipse, and when the angle of the ultrasonic irradiation surface 111 is changed (the arrow in the figure indicates the direction of change of the angle), the radius on the wafer It may be a flat shape that changes the ultrasonic energy received depending on the position in the direction, and may be, for example, an elongated rectangle. From the experimental results, it is clear that the effect of the present invention can be sufficiently obtained if the ratio of the length of the minor axis to the major axis of the ultrasonic irradiation surface 111 is at least three times the major axis. Yes. In addition, if the major axis is longer than the minor axis, the time for irradiating the ultrasonic wave can be relatively increased in the cleaning of the outer peripheral portion of the wafer, but if it is too long, the outer peripheral portion is irradiated. The amount of ultrasonic energy is greater than in the center. Therefore, the major axis is preferably about 3 to 5 times the minor axis. Here, synthetic quartz is used as the material of the vibrating body 110. However, the material of the vibrating body 110 is not limited to synthetic quartz, and can be freely selected as long as it is a material that does not corrode by the cleaning liquid, has little impurity elution, and propagates ultrasonic vibrations satisfactorily. Good.

  The ultrasonic transducer 120 is connected to a high frequency power source by a high frequency power cable (not shown), and here, ultrasonically vibrates at a frequency of 3 MHz and an output of 60 W.

  The irradiation surface angle control unit 130 includes, for example, a servo motor and its control unit, and rotates the vibrating body unit 100 precisely to change the direction (angle) of the ultrasonic irradiation surface 111 on the wafer. The operation of the irradiation surface angle control unit 130 is linked to the reciprocating motion of the vibrating body moving mechanism to which the support arm 140 is fixed, and the vibrating body moving mechanism and the irradiation surface angle control unit 130 are not shown. Controlled by a control computer.

  Next, the arrangement and operation of the vibrating body unit 100 on the wafer 10 will be described. FIG. 5 shows a state in which the ultrasonic irradiation surface 111 of the vibrator unit 100 is arranged at a position spaced apart from the surface of the wafer 10 to be cleaned by a certain distance (about 1 mm in this case). In this state, the ultrasonic irradiation surface 111 faces the surface (cleaning surface) of the wafer 10. The wafer 10 is placed horizontally on a wafer chuck (not shown), fixed by, for example, vacuum suction, and horizontally rotated by the rotation of the wafer chuck.

  A cleaning liquid supply nozzle 150 is disposed near the vibrating body unit 100 and discharges the cleaning liquid 20 onto the surface of the wafer 10. Since the wafer 10 is rotating, the cleaning liquid 20 discharged onto the surface of the wafer 10 spreads uniformly on the wafer 10 and a film of the cleaning liquid 20 having a uniform thickness is formed. As a result, the space between the ultrasonic irradiation surface 111 and the surface of the wafer 10 is filled with the cleaning liquid 20. The cleaning liquid supply unit described above corresponds to the cleaning liquid supply nozzle 150.

Next, an example in which the vibrating body unit 100 reciprocates in the radial direction of the wafer 10 by the vibrating body moving mechanism and the direction of the ultrasonic irradiation surface 111 is changed depending on the radial position of the wafer 10 will be described. FIG. 6 shows the orientation (angle) of the ultrasonic irradiation surface 111 at each position of Q0, Q1, Q2,. Here, the position of Q0 is the rotation center position of the wafer 10, the position of Q4 is a position where the outer peripheral edge of the vibrating body 110 is substantially in contact with the outer peripheral edge of the wafer 10, and the length L between Q0 and Q4 is set as the vibrating body unit. 100 reciprocates (the positions of Q1 to Q4 are positions obtained by dividing L into four equal parts). The direction of the ultrasonic irradiation surface 111 at the position of Q0 is such that the longitudinal direction of the ultrasonic irradiation surface 111 coincides with the direction of reciprocating motion (the ultrasonic irradiation surface 111 is horizontal, that is, 0 °). The longitudinal direction of the ultrasonic irradiation surface 111 and the direction of the reciprocating motion are perpendicular to each other at a position (the ultrasonic irradiation surface 111 is vertical, that is, 90 °). The angle between Q0 and Q4 changes linearly and continuously. That is, the angle (A) of the ultrasonic irradiation surface 111 and the movement distance (X) in the radial direction from the center of the wafer are represented by the following equations (L is the distance from the wafer center to the outer periphery shown in FIG. 6). .
A = (90 / L) * X (0 ≦ X ≦ L)

  By changing the direction of the ultrasonic irradiation surface 111 as described above, the irradiation amount of ultrasonic energy received by the portion at the outer peripheral position of the wafer 10 becomes larger than the example shown in FIG. The amount of ultrasonic energy received is reduced. That is, the ultrasonic irradiation surface 111 changes from horizontal (0 °) to vertical (90 °) as the vibrating body 110 moves from the center of the wafer 10 toward the outer periphery, or from vertical as the oscillator 110 moves from the outer periphery toward the center. By changing horizontally, ultrasonic irradiation can be performed uniformly over the entire surface of the wafer 10. This eliminates the problem of excessive ultrasonic energy being irradiated near the center of rotation. Further, the time required for cleaning is shortened by eliminating the need for excessive ultrasonic irradiation.

  The above-described control computer calculates the direction of the ultrasonic irradiation surface 111 based on how far the vibrator unit 100 is in the radial direction from the center of rotation of the wafer 10, and calculates the result as the irradiation surface angle. The control unit 130 is instructed to control the angle of the vibrating body 110 (that is, the ultrasonic irradiation surface 111).

  Next, a vibrating body moving mechanism that performs the reciprocating motion of the vibrating body unit 100 will be described. FIG. 7 shows the structure of a vibrating body moving mechanism 200 that moves the vibrating body unit 100 in the radial direction with respect to the wafer 10 placed in the cleaning chamber 300. FIG. 7B is a cross-sectional view taken along the line AA ′ shown in the top view.

  Prior to the description of the vibrating body moving mechanism 200, the wafer chuck 320 that supports and rotates the cleaning chamber 300 and the wafer 10 will be described. The cleaning chamber 300 is a space embedded in the upper surface of a cleaning device described later and has a wide circular opening toward the top. A wafer chuck 320 for horizontally supporting and further rotating the wafer 10 that is the object to be cleaned is disposed at substantially the center of the bottom surface of the cleaning chamber 300. The wafer chuck 320 is connected to a motor (not shown) and is rotatable. A cup 310 for preventing the cleaning liquid from splashing outside the cleaning chamber 300 due to the rotation of the wafer 10 is provided on the outer edge portion above the cleaning chamber 300.

  Next, the structure of the vibrating body moving mechanism 200 will be described. The vibrating body moving mechanism 200 is disposed on the upper surface of the cleaning apparatus, and is positioned above the cleaning chamber 300 described above. The vibrating body moving mechanism 200 includes a beam 210, a guide rail 220, and a slider 230. As shown in FIG. 7A, the two guide rails 220 are arranged with the cleaning chamber 300 interposed therebetween, and the beam 210 slides on the guide rail 220 via the slider 230. In the center of the beam 210, the vibrating body unit 100 is installed via the support arm 140 and the irradiation surface angle control unit 130. A cleaning liquid supply nozzle 150 is also disposed on the beam 210.

  The vibrating body moving mechanism 200 has a structure that can be moved up and down in a column of the guide rail 220 or the housing of the cleaning device by a driving unit (not shown). FIG. 7 shows a state in which the wafer 10 is being exchanged. The guide rail 220 is in a position raised by the drive unit, and the vibrator unit 100 is retracted to the retreat spot 330 removed from the cleaning chamber 300.

  Next, the state during cleaning will be described with reference to FIG. 8A is a top view, and FIG. 8B is a cross-sectional view taken along the line B-B ′ shown in the top view. As shown in FIG. 8B, the guide rail 220 is in a position lowered (sunk) by the drive unit into the housing of the cleaning apparatus, and the ultrasonic irradiation surface 111 of the vibrating body unit 100 is moved down the wafer 10 by the lowering. It is close to a predetermined distance from the surface. In this state, the vibrator unit 100 mounted on the beam 210 reciprocates between the rotation center of the wafer 10 and the outer peripheral portion as indicated by an arrow. The vibrating body unit 100 changes the direction (angle) of the ultrasonic irradiation surface 111 by the irradiation surface angle control unit 130 in cooperation with the reciprocating motion.

  The cleaning operation will be described in more detail. At the start of the cleaning operation, the vibrator unit 100 is at the retreat spot 330, and the guide rail 220 is lifted upward (state shown in FIG. 7). From this state, the vibrator unit 100 is moved to a predetermined position on the outer peripheral portion of the wafer 10 (for example, a position above Q4 in FIG. 6). The vibrating body unit 100 is moved by sliding the slider 230 on the guide rail 220. When the vibrating body unit 100 reaches a predetermined position, the guide rail 220 is lowered to bring the ultrasonic irradiation surface 111 of the vibrating body 110 closer to a position about 1 mm away from the wafer 10. At this position, the longitudinal direction of the ultrasonic irradiation surface 111 is set to be perpendicular to the direction of reciprocation.

  Subsequently, the wafer 10 is rotated, the cleaning liquid is supplied from the cleaning liquid supply nozzle 150 onto the wafer 10, and a film of the cleaning liquid is formed on the surface of the wafer 10. By operating the ultrasonic vibrator 120 and the slider 230 reciprocatingly moving on the guide rail 220 in the direction of the arrow shown in FIG. 8, the ultrasonic irradiation surface 111 sweeps and cleans the entire surface of the wafer 10. As described above, the movement operation of the slider 230 and the angle changing operation of the irradiation surface angle control unit 130 are linked, and the irradiation surface angle is determined according to the radial position of the ultrasonic irradiation surface 111 on the wafer 10. The direction (angle) of the ultrasonic irradiation surface 111 is changed by the control unit 130. The above series of operations is controlled by a control computer (not shown). Here, the vibrating body 110 is reciprocated between the outer periphery and the center of the wafer 10, but may be reciprocated so as to move from the outer periphery to the outer periphery that is the point target and turn back. . The vibrating body moving mechanism 200 linearly moves the vibrating body unit 100 in the radial direction of the wafer 10. However, an arm having a predetermined position outside the cleaning chamber 300 as a fulcrum is provided, and the vibrating body unit 100 is provided at the tip of the arm. And the irradiation surface angle control unit 130 may be arranged so that the vibrating body unit 100 reciprocates between the outer periphery and the center of the wafer 10 by drawing an arc.

  Next, FIG. 9 shows the entire structure of the cleaning device 500 on which the vibrating body unit 100 and the vibrating body moving mechanism 200 are mounted. 9 is a top view of the cleaning device 500, the lower left is a front view, and the lower right is a side view. Components for performing cleaning operations such as the cleaning chamber 300 and the vibrating body moving mechanism 200 shown in FIGS. 7 and 8 are horizontally arranged on the upper surface of the casing 400 of the cleaning apparatus 500. Further, components such as a wafer rack 410 for storing wafers before and after cleaning and a wafer transfer mechanism 420 for transferring wafers between the wafer rack 410 and the cleaning chamber 300 are also installed. In order to prevent these components from being contaminated by airborne foreign substances in the atmosphere, a clean booth 430 is installed on the upper surface of the housing 400 so as to cover these components, and the inside thereof is clean. Is maintained in a high environment. The cleaning process is performed in the clean booth 430. The above-described control computer (not shown) is installed in the housing 400, and a series of processes of the cleaning apparatus 500 receives an operator's instruction via an operation panel 440 connected to the control computer, and an automated cleaning process recipe is used. Done.

  Next, the result of the confirmation experiment using the cleaning apparatus 500 shown in the present embodiment will be described. The wafer used for the experiment was a silicon wafer having a diameter of 8 inches (200 mm), and a porous silica film having a thickness of 200 nm was formed on the surface of the wafer. This film was processed by dry etching to form a uniform striped pattern with L / S (Line / Space) = 60/60 nm and a depth of 100 nm. About 50,000 silica (SiO 2) fine particles having an average particle diameter of 0.15 μm were adhered to the surface of this wafer to prepare a sample.

  In the evaluation of cleaning, the number of silica particles adhering to the wafer surface before and after cleaning is measured, and when the silica particle removal rate becomes 99% or more, the cleaning is completed and the time required for the cleaning is measured. It was decided. In addition, the pattern destruction state after completion of cleaning was observed using a pattern inspection apparatus.

  The shape of the ultrasonic irradiation surface of the vibrating body in this experiment is an ellipse having a minor axis of 10 mm and a major axis of 40 mm, and in cleaning, the direction of the ultrasonic irradiation surface is changed depending on the position of the wafer as described in the examples. To do. In order to confirm the effect of the present invention, cleaning was also performed using a vibrator having a circular ultrasonic irradiation surface with a diameter of 15 mm. In this case, the direction of the ultrasonic irradiation surface is constant (even if the direction is changed, it is constant because it is circular). The materials of the vibrators are all synthetic quartz, the vibration frequency of the ultrasonic waves generated by the ultrasonic vibrator is 3 MHz, and the output is 60 W.

  The wafer was rotated at a speed of 150 rpm. From the cleaning liquid supply nozzle, hydrogen-dissolved water in which hydrogen gas is dissolved at a concentration of 1.5 mg / L is supplied into ultrapure water, and a film having a thickness of about 2 mm is formed on the wafer surface while the wafer is rotating. The flow rate was adjusted to form. The interval between the ultrasonic irradiation surface and the wafer surface was fixed at 1.0 mm. The vibrating body unit reciprocated between the center and the outer periphery of the wafer at a constant speed of 50 mm / sec on the wafer.

  First, cleaning was performed using a vibrating body having a circular ultrasonic irradiation surface. As a result, it took 720 seconds on average to complete the cleaning of the entire wafer surface. As for the pattern destruction state, many pattern collapses were confirmed within a radius of 30 mm from the center of the wafer.

  Next, in the vibrating body having an elliptical ultrasonic irradiation surface according to the present invention, cleaning was completed in 460 seconds, and pattern destruction was not observed. As a result, it was confirmed that the variation of the ultrasonic energy irradiated to the wafer was suppressed, and the destruction of the pattern at the central portion of the wafer due to excessive ultrasonic energy irradiation could be prevented. It was also confirmed that the cleaning time for the entire wafer was shortened by using the method of the present invention.

  As mentioned above, although the Example of the washing | cleaning apparatus and washing | cleaning method of this invention was described, these are not limited to above content, In the range which does not deviate from the summary of this invention, it can implement in various aspects. .

DESCRIPTION OF SYMBOLS 10 Wafer 20 Cleaning liquid 30 Ultrasonic nozzle 40 Arm 50 Ultrasonic vibrator 51 Vibrating body 51a Surface 51b Ultrasonic irradiation surface 60 Cleaning liquid supply nozzle 100 Vibrating body unit 110 Vibrating body 111 Ultrasonic irradiation surface 120 Ultrasonic vibrator 130 Irradiation surface angle Control unit 140 Support arm 150 Cleaning liquid supply nozzle 200 Vibrating body moving mechanism 210 Beam 220 Guide rail 230 Slider 300 Cleaning chamber 310 Cup 320 Wafer chuck 330 Retraction spot 400 Housing 410 Wafer rack 420 Wafer transfer mechanism 430 Clean booth 440 Operation panel 500 Cleaning apparatus

Claims (3)

A vibrating body unit comprising: an ultrasonic vibrator that generates ultrasonic waves; and a vibrating body that is fixed to the ultrasonic vibrator and has a flat ultrasonic irradiation surface that irradiates the cleaning liquid with the ultrasonic waves;
An irradiation surface angle control unit that rotates the vibrating body unit and changes an angle of the ultrasonic irradiation surface around a direction intersecting the ultrasonic irradiation surface;
A substrate rotating unit for holding the substrate to be cleaned and rotating the substrate;
A vibrating body moving mechanism for moving the vibrating body unit while maintaining a predetermined interval with the ultrasonic irradiation surface of the vibrating body facing the cleaning surface of the substrate;
A cleaning liquid supply unit that supplies the cleaning liquid between the ultrasonic irradiation surface and the cleaning surface;
The vibrating body moving mechanism moves the vibrating body unit between at least one outer peripheral position of the substrate and a center position of the substrate,
When the vibrator unit is at the outer peripheral position, the longitudinal direction of the ultrasonic irradiation surface of the vibrator is perpendicular to the moving direction of the vibrator unit, and the vibrator unit is at the center position. The cleaning apparatus is characterized in that the longitudinal direction is continuously changed in a direction parallel to the moving direction of the vibrating body unit . The vibrator has a length at least three times longer than a short dimension of the ultrasonic irradiation surface.
The cleaning apparatus according to claim 1. Rotate the substrate while holding the substrate with the cleaning surface facing upward,
Holding the flat ultrasonic irradiation surface of the vibrating body fixed to the ultrasonic vibrator toward the cleaning surface at a certain interval, moving the vibrating body in the radial direction of the substrate while filling the cleaning liquid in the interval, When the ultrasonic irradiation surface is at the outer peripheral position of the substrate along with the movement, the longitudinal direction of the ultrasonic irradiation surface of the vibration body is perpendicular to the movement direction of the vibration unit, and the vibration body When the unit is at the center position, the ultrasonic wave is irradiated while changing the longitudinal direction in a direction parallel to the moving direction of the vibrating body unit.
A cleaning method characterized by the above.

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