JP2009231667A - Method for processing substrate and substrate processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for processing a substrate that improves the uniformity of cleaning effects by efficiently irradiating ultrasonic waves to an entire region of the substrate to be cleaned without complicating the structure of a substrate processing device when cleaning the substrate by irradiating the ultrasonic waves to the substrate immersed in a cleaning liquid in a processing tank. <P>SOLUTION: The ultrasonic waves are irradiated to the substrate by displacing each phase of a plurality of ultrasonic vibrator groups 22 which are parallel disposed in a direction perpendicular to an arrangement direction of the substrate (W) so that there is mutual compatibility between the transition status of flow dynamics distribution generated when the cleaning liquid supplied through a discharge pipe 20 is spread in the cleaning fluid in a processing tank 10 and the progress status of a composite wave surface formed when the ultrasonic waves irradiated from a bottom side of the processing tank 10 are propagated in the cleaning liquid in the processing tank. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In the present invention, various substrates such as a semiconductor wafer, a glass substrate for a liquid crystal display (LCD), a glass substrate for a plasma display (PDP), a glass / ceramic substrate for a magnetic / optical disk, and an electronic device substrate are immersed in a cleaning solution. However, the present invention relates to a substrate processing method for cleaning a substrate by irradiating the substrate with ultrasonic waves from the bottom side of the processing tank, and a substrate processing apparatus used for performing the processing method.

  Conventionally, an ultrasonic cleaning method using ultrasonic waves is generally used for cleaning a substrate such as a semiconductor wafer or a glass substrate for LCD. This ultrasonic cleaning method uses the effects of cavitation, vibration acceleration, straight flow (flow of cleaning liquid), etc. generated in the cleaning liquid by ultrasonic vibration, and dirt, particles, organic substances, impurities, etc. adhering to the surface of the substrate. It is a method of removing.

  By the way, in recent years, with the miniaturization of semiconductor devices, the miniaturization of patterns formed on the surface of a substrate has progressed. Under such circumstances, in ultrasonic cleaning using cavitation at a low frequency of 50 kHz or less, there is a problem that the surface of the substrate on which a fine pattern is formed is damaged by physical force resulting from cavitation. . On the other hand, in ultrasonic cleaning using high frequency, the effects of vibration acceleration generated in the cleaning liquid and the effect of straight flow are mainly used, and the occurrence of cavitation is small, so the ultrafine particles of dirt to be removed are removed and the surface of the substrate is Is reduced.

  In a batch type ultrasonic cleaning apparatus, a plurality of substrates are held by a substrate holder and fixed in a processing tank, and a cleaning liquid is supplied into the processing tank, while the bottom wall outer surface side (or side wall outer surface side) of the processing tank is supplied. The substrate is cleaned by irradiating the inside of the processing tank with ultrasonic waves from an ultrasonic vibration plate (vibrator) attached to (). Then, in order to cope with the pattern miniaturization associated with the semiconductor device described above, high-frequency ultrasonic vibration of 1 MHz or higher is used. However, since high frequency is used for the irradiation of ultrasonic waves, the straightness of ultrasonic waves irradiated into the inside of the treatment tank becomes strong, and the following problems appear.

  FIG. 9 is a schematic cross-sectional view showing an example of a schematic configuration of a batch-type ultrasonic cleaning apparatus. This cleaning apparatus is arranged on the left and right sides near the bottom of the processing tank 1, a processing tank 1 for storing cleaning liquid, a substrate holder (lifter) having holding parts 2 and 3 for holding substrates W such as a plurality of semiconductor wafers. A pair of discharge pipes 4, 4 that discharge cleaning liquid toward the inside of the treatment tank 1, a propagation tank 5 that is provided integrally with the treatment tank 1 on the outer surface of the bottom wall of the treatment tank 1, and is filled with propagation water, The ultrasonic vibration plate 6 is attached to the outer surface of the bottom wall of the tank 5, the ultrasonic oscillator 7 is connected to the ultrasonic vibration plate 6, and the like. In the ultrasonic cleaning apparatus having such a configuration, the ultrasonic vibration plate 6 is operated by the ultrasonic oscillator 7 to generate high-frequency ultrasonic vibration, and the substrate W held in the processing tank 1 by the substrate holder is applied to the substrate W. When high frequency ultrasonic waves are irradiated, the ultrasonic wave is absorbed and reflected by the holding parts 2 and 3 of the substrate holder. In this case, since the ultrasonic wave has a strong straight traveling property, as shown in FIG. 9, a portion that is shaded in a region on the back side of the holding portions 2 and 3 of the substrate holder with respect to the traveling direction of the ultrasonic wave (Part where ultrasonic waves are not sufficiently irradiated) 8 and 9 are generated. As a result, there is a problem in that cleaning unevenness occurs on the surface of the substrate W, and uniformity in the surface of the substrate W cannot be obtained in cleaning performance.

In order to prevent the above-described cleaning unevenness, various ultrasonic cleaning apparatuses and ultrasonic cleaning methods have been conventionally proposed. For example, a vertically movable wafer chuck that holds a plurality of wafers and carries them into the cleaning tank, and a vertically movable wafer that is disposed at the bottom of the cleaning tank and receives and holds a plurality of wafers from the vertically movable wafer chuck. An ultrasonic cleaning apparatus including a lifter type wafer guide has been proposed. In this cleaning apparatus, in the first cleaning stage, the wafer moving up and down is held in an open state where the wafer is not held, and the wafer is held by the lifter type wafer guide for cleaning. At this stage, since the ultrasonic wave is not sufficiently applied to the shadowed portion of the lifter type wafer guide, a uniform cleaning effect over the entire surface of the wafer cannot be obtained. However, in the second cleaning stage, the vertically movable wafer chuck is The wafer is closed and held, and the wafer chuck is raised in this state, and cleaning is performed by holding the wafer on the wafer chuck at a height position where the upper end of the wafer is not exposed from the surface of the cleaning liquid in the cleaning tank. At this time, since the distance between the lower portion of the wafer and the horizontal portion (holding portion) of the wafer guide is larger than that in the first cleaning step, it is possible to minimize the region where the portion that is shaded by the wafer guide and the wafer overlap. it can. As a result, the entire area of the wafer can be cleaned (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2006-324495 (page 4-5, FIGS. 3 to 5)

  According to the configuration of the ultrasonic cleaning apparatus proposed in Patent Document 1, it is possible to irradiate an ultrasonic wave to the shadowed area of the wafer guide. The part that is not irradiated cannot be completely eliminated. Another problem is that the structure of the ultrasonic cleaning apparatus is complicated.

  The present invention has been made in view of the circumstances as described above, and complicates the structure of the apparatus when the substrate is immersed in the cleaning liquid in the processing tank to clean the substrate by irradiating ultrasonic waves. It is possible to provide a substrate processing method capable of effectively irradiating the entire cleaning surface of the substrate with ultrasonic waves to enhance the uniformity of the cleaning effect, and to suitably execute the processing method. An object is to provide a substrate processing apparatus.

  A plurality of substrates are arranged along the arrangement direction of the plurality of substrates in the vicinity of the bottom of the processing tank in a state in which the plurality of substrates are arranged in parallel and horizontally in the vertical posture by the substrate holding means and held in the processing tank. When the cleaning liquid is supplied from the cleaning liquid supply means toward the inside of the processing tank, the cleaning liquid supplied from the cleaning liquid supply means diffuses into the cleaning liquid in the processing tank and flows in the processing tank. In addition, a plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers arranged side by side in a direction orthogonal to the arrangement direction of the plurality of substrates on the bottom side of the processing tank with respect to the plurality of substrates held by the substrate holding means When the ultrasonic waves are irradiated from the ultrasonic wave, the ultrasonic waves irradiated from the individual ultrasonic transducer groups or the ultrasonic transducers are synthesized and propagated through the cleaning liquid in the treatment tank. According to the first aspect of the present invention, when viewed in a cross section orthogonal to the arrangement direction of a plurality of substrates, the flow distribution transition state when the cleaning liquid diffuses into the cleaning liquid in the processing tank and the ultrasonic wave are processed. The phases of the ultrasonic waves radiated from multiple ultrasonic transducer groups or multiple ultrasonic transducers are mutually matched so that the progress of the composite wavefront when propagating the cleaning liquid in the tank is compatible with each other. It is characterized by shifting.

  According to a second aspect of the present invention, there is provided the substrate processing method according to the first aspect, wherein the cleaning liquid is symmetrically provided in a left-right direction from a pair of cleaning liquid supply means disposed symmetrically on both sides near the bottom of the processing tank. The phases of the ultrasonic waves respectively supplied from a plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers arranged side by side in a symmetrical manner are The ultrasonic transducer group or the ultrasonic transducers are matched with each other, and the ultrasonic transducer group or the ultrasonic transducer at the center position in the direction orthogonal to the arrangement direction of the plurality of substrates is located away from the ultrasonic transducer group. The ultrasonic transducer group or the ultrasonic transducer is sequentially delayed.

  The invention according to claim 3 is the arrangement of a plurality of substrates in the vicinity of the bottom of the processing tank in a state where a plurality of substrates are held in the processing tank in a vertical posture parallel to each other and horizontally by the substrate holding means. While supplying the cleaning liquid from the cleaning liquid supply means arranged along the direction toward the inside of the processing tank, the plurality of substrates held by the substrate holding means are irradiated with ultrasonic waves from the bottom side of the processing tank, In the method for cleaning a plurality of substrates, ultrasonic waves are respectively emitted from a plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers arranged in parallel in a direction orthogonal to the arrangement direction of the plurality of substrates. Alternatively, the first step of irradiating the phase sequentially in accordance with the arrangement order of the ultrasonic transducers and the ultrasonic waves from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers, respectively. Arrangement of acoustic transducer A second step of irradiating complete the sequence phase according order, characterized in that it comprises a.

  The invention according to claim 4 is the substrate processing method according to claim 3, characterized in that the first step and the second step are alternately repeated.

  The invention according to claim 5 is the substrate processing method according to claim 3, further comprising a third step of irradiating ultrasonic waves from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers in the same phase. It is characterized by including.

  The invention according to claim 6 is the substrate processing method according to claim 5, wherein the first step and the second step are alternately repeated with the third step interposed therebetween. .

  The invention according to claim 7 is the processing tank in which the cleaning liquid is stored and the plurality of substrates are supported in a vertical posture with the lower end portions thereof supported by the holding portions and arranged in parallel and in the horizontal direction. A substrate holding means for holding inside the substrate, and disposed in the vicinity of the bottom of the processing tank along the arrangement direction of the plurality of substrates held by the substrate holding means, and discharging a cleaning liquid toward the inside of the processing tank Cleaning liquid supply means, and ultrasonic irradiation means for irradiating ultrasonic waves from the bottom side of the processing tank to the plurality of substrates held by the substrate holding means, and a plurality of holding means held by the substrate holding means In a substrate processing apparatus for cleaning a substrate, a plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers arranged in parallel in a direction orthogonal to the arrangement direction of the plurality of substrates, and the plurality of ultrasonic transducer groups or Multiple ultrasonic transducers The flow distribution in a cross section perpendicular to the arrangement direction of the plurality of substrates when the cleaning liquid supplied from the connected ultrasonic oscillator and the processing liquid supply means diffuses into the cleaning liquid in the processing tank. The transition state and the progress of the composite wavefront in the cross section perpendicular to the arrangement direction of the plurality of substrates when the ultrasonic wave irradiated from the bottom side of the processing tank propagates through the cleaning liquid in the processing tank. A control circuit that controls to shift the phases of the oscillating waves respectively sent from the ultrasonic oscillator to the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers so as to be compatible with each other. And

  According to an eighth aspect of the present invention, in the substrate processing apparatus of the seventh aspect, a pair of the cleaning liquid supply means is provided symmetrically on both sides near the bottom of the processing tank, and the cleaning liquid is supplied from the pair of cleaning liquid supply means. Each of the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers is arranged symmetrically so as to be supplied symmetrically and obliquely downward toward the central direction inside the processing tank, and the control circuit, The phases of the ultrasonic waves respectively irradiated from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers are matched between the ultrasonic transducer groups or the ultrasonic transducers at the left and right symmetrical positions, and The ultrasonic transducer group or ultrasonic transducer at a position far from the ultrasonic transducer group or ultrasonic transducer at the central position in the direction orthogonal to the arrangement direction of the plurality of substrates And controlling to delay sequentially as children.

  According to the ninth aspect of the present invention, there is provided a processing tank for storing a cleaning liquid and a plurality of substrates in a state where the lower ends thereof are supported by a holding part and arranged in parallel and horizontally in a vertical posture. A substrate holding means for holding inside the substrate, and disposed in the vicinity of the bottom of the processing tank along the arrangement direction of the plurality of substrates held by the substrate holding means, and discharging a cleaning liquid toward the inside of the processing tank Cleaning liquid supply means, and ultrasonic irradiation means for irradiating ultrasonic waves from the bottom side of the processing tank to the plurality of substrates held by the substrate holding means, and a plurality of holding means held by the substrate holding means In a substrate processing apparatus for cleaning a substrate, a plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers arranged in parallel in a direction orthogonal to the arrangement direction of the plurality of substrates, and the plurality of ultrasonic transducer groups or Multiple ultrasonic transducers Ultrasonic waves are emitted from the connected ultrasonic oscillator and the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers, respectively, with the phase sequentially delayed in accordance with the arrangement order of the ultrasonic transducer groups or ultrasonic transducers. A first state and a second state in which ultrasonic waves are respectively emitted from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers while sequentially proceeding in phase according to the arrangement order of the ultrasonic transducer groups or the ultrasonic transducers. And a control circuit that controls to switch between these states.

  According to a tenth aspect of the present invention, in the substrate processing apparatus according to the ninth aspect, the control circuit controls the first state and the second state to be alternately repeated. .

  According to an eleventh aspect of the present invention, in the substrate processing apparatus according to the ninth aspect, the control circuit irradiates ultrasonic waves from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers in the same phase. 3, the first state, and the second state are controlled to be switched alternatively.

  According to a twelfth aspect of the present invention, in the substrate processing apparatus of the eleventh aspect, the first state and the second state are alternately repeated by the control circuit with the third state interposed therebetween. It is controlled to be controlled.

  According to a thirteenth aspect of the present invention, in the substrate processing apparatus according to any one of the seventh to twelfth aspects, the ultrasonic oscillator is a pulse oscillator that oscillates a pulse wave.

  The invention according to claim 14 is the substrate processing apparatus according to any one of claims 7 to 13, wherein the control circuit includes the ultrasonic oscillator and the plurality of ultrasonic transducer groups or a plurality of ultrasonic vibrations. It includes a plurality of delay circuits respectively inserted between the children.

According to the substrate processing method of the first aspect of the present invention, the ultrasonic waves are irradiated from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers with the phases shifted from each other. The combined wavefronts obtained by synthesizing the ultrasonic waves respectively irradiated from the acoustic wave transducers progress upward in the cleaning liquid in the processing tank in a curved surface rather than a mere horizontal plane. For this reason, the ultrasonic wave apparently propagates in a direction inclined with respect to the vertical direction depending on the position inside the processing tank. As a result, it is possible to minimize occurrence of a shadowed portion (portion where ultrasonic waves are not sufficiently irradiated) on the back side of the holding portion of the substrate holding means with respect to the traveling direction of the ultrasonic waves.
Therefore, when performing ultrasonic cleaning of a substrate using the substrate processing method according to the first aspect of the present invention, it is possible to effectively irradiate the entire cleaning surface of the substrate with ultrasonic waves to improve the uniformity of the cleaning effect. it can. In addition, since a plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers are arranged in parallel on the bottom side of the processing tank and the phase of the ultrasonic wave irradiated from them is simply shifted, the structure of the apparatus becomes complicated. There is nothing. Furthermore, since the synthetic wavefront of the ultrasonic wave advances so as to match the transition state of the flow distribution of the cleaning liquid in the cleaning liquid in the processing tank, the substrate cleaning effect can be enhanced.

  According to the substrate processing method of the invention according to claim 2, the cleaning liquid supplied obliquely downward from the pair of cleaning liquid supply means disposed on both sides near the bottom of the processing tank toward the central direction inside the processing tank, It rises symmetrically from the bottom to the top of the treatment tank. The upward flow at this time is substantially linear at the center of the processing tank, but greatly curves outward as it goes from the center of the processing tank to the left and right sides. On the other hand, the progress of individual ultrasonic waves respectively irradiated from a plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers arranged side by side symmetrically on the bottom side of the processing tank is compared to the central portion of the processing tank. The more you move to the left and right sides, the more you delay. For this reason, the synthesized wavefront obtained by synthesizing the individual ultrasonic waves has an arc shape opened downward, and proceeds upward in the same manner as the flow distribution of the cleaning liquid in the processing tank. Therefore, the above-mentioned effect of the invention according to claim 1 can be reliably achieved.

According to the substrate processing method of the invention of claim 3, in the first step, the ultrasonic waves are irradiated from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers with the phase being sequentially delayed according to the arrangement order. Therefore, the combined wavefront obtained by synthesizing the ultrasonic waves respectively irradiated from the individual ultrasonic transducer groups or the ultrasonic transducers is apparently inclined with respect to the horizontal plane in the direction orthogonal to the arrangement direction of the plurality of substrates. It propagates through the cleaning liquid in the treatment tank. On the other hand, in the second step, ultrasonic waves are emitted from a plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers with the phase being sequentially advanced according to the arrangement order. The combined wavefront obtained by synthesizing the ultrasonic waves respectively irradiated from the acoustic wave oscillator is apparently inclined in the direction perpendicular to the arrangement direction of the plurality of substrates in a direction inclined to the opposite side with respect to the horizontal plane. Propagate through. As described above, since the traveling direction of the composite wavefront of the ultrasonic wave changes, a shadowed portion on the back side of the holding unit of the substrate holding unit with respect to the traveling direction of the ultrasonic wave (a portion where the ultrasonic wave is not sufficiently irradiated) As a result, the area of a portion that always becomes a shadow when viewed in a cross section orthogonal to the arrangement direction of the plurality of substrates is reduced.
Therefore, when performing ultrasonic cleaning of a substrate using the substrate processing method of the invention according to claim 3, it is possible to effectively irradiate the entire cleaning surface of the substrate with ultrasonic waves to improve the uniformity of the cleaning effect. it can. In addition, since a plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers are arranged in parallel on the bottom side of the processing tank, and only the phase of the ultrasonic wave irradiated from them is delayed or advanced, the structure of the apparatus There is no complication.

  In the substrate processing method according to the fourth aspect of the present invention, the first and second steps are alternately repeated, so that the above-described effect of the third aspect of the invention can be reliably obtained.

  According to the substrate processing method of the invention of claim 5, in the third step, since the ultrasonic waves are irradiated with the same phase from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers, A combined wavefront obtained by synthesizing ultrasonic waves respectively emitted from the group of ultrasonic transducers or ultrasonic transducers travels upward in the cleaning liquid in the processing tank in a horizontal plane. By including this third step, the area of the portion that is always shadowed when viewed in a cross section orthogonal to the arrangement direction of the plurality of substrates is further reduced. Therefore, the substrate processing method of the invention according to claim 5 is provided. When used, the uniformity of the cleaning effect can be further increased.

  In the invention according to claim 6, the above-described effect of the invention according to claim 5 can be reliably obtained by alternately repeating the first step and the second step with the third step interposed. .

  When the substrate processing apparatus of the invention according to claim 7 is used for ultrasonic cleaning of a substrate, the method of the invention according to claim 1 can be suitably carried out, so that the above effect of the invention according to claim 1 is obtained. Can do.

  When the substrate processing apparatus of the invention according to claim 8 is used, the method of the invention according to claim 2 can be suitably implemented, so that the above-described effect of the invention according to claim 2 can be obtained.

  When the substrate processing apparatus of the invention according to claim 9 is used for ultrasonic cleaning of a substrate, the method of the invention according to claim 3 can be suitably carried out, so that the effect of the invention according to claim 3 is obtained. Can do.

  When the substrate processing apparatus of the invention according to claim 10 is used, the method of the invention according to claim 4 can be suitably carried out, so that the effect of the invention according to claim 4 can be obtained.

  When the substrate processing apparatus of the invention according to claim 11 is used, the method of the invention according to claim 5 can be suitably carried out, so that the effect of the invention of claim 5 can be obtained.

  When the substrate processing apparatus according to the twelfth aspect of the invention is used, the method of the invention of the sixth aspect of the invention can be suitably carried out, so that the effect of the invention according to the sixth aspect can be obtained.

  In the substrate processing apparatus of the invention according to the thirteenth aspect, the effects of the inventions according to the seventh to twelfth aspects can be reliably achieved by oscillating the pulse wave from the pulse oscillator.

  In the substrate processing apparatus of the invention according to claim 14, a plurality of ultrasonic vibrations are provided by a plurality of delay circuits respectively inserted between the ultrasonic oscillator and the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers. The effects of the inventions according to the seventh to twelfth aspects can be reliably achieved by shifting, sequentially delaying, or advancing the phase of the ultrasonic waves respectively irradiated from the child group or the plurality of ultrasonic transducers.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a substrate processing apparatus for ultrasonically cleaning a substrate, showing an example of an embodiment of the present invention.

  The substrate processing apparatus includes a processing tank 10 having an upper surface opened and storing a cleaning liquid, and a substrate holder (lifter) that holds a plurality of substrates W such as semiconductor wafers. A liquid receiving portion 12 into which the processing liquid overflowing from the upper end of the processing tank 10 flows is provided on the outer periphery of the upper part of the processing tank 10, and integrally with the processing tank 10 on the outer surface of the bottom wall of the processing tank 10, A propagation tank 14 filled with propagation water such as pure water is provided. Although detailed description of the structure of the substrate holder is omitted, a lifter portion (not shown) arranged in the vertical direction and a lower end portion of the lifter portion are attached to the lower end portion of the substrate W, respectively. A central holding portion 16 and left and right holding portions 18, 18. Each holding portion 16, 18 is formed with a plurality of substrate holding grooves that engage with the peripheral edge of the substrate W. Then, the plurality of substrates W are held in a vertical posture by the substrate holder in a state of being arranged in the horizontal direction with a slight gap therebetween, inserted into the processing bath 10 and stored in the processing bath 10. It is immersed in the cleaning liquid, and is pulled up from the cleaning liquid in the processing tank 10 and discharged to a position above the processing tank 10.

  A pair of discharge pipes 20 and 20 for discharging the cleaning liquid are provided on the left and right sides near the bottom of the processing tank 10. Each discharge tube 20 is disposed so as to extend along the arrangement direction of the plurality of substrates W held by the substrate holder (in a direction perpendicular to the paper surface). For example, a plurality of slit-shaped discharge ports are arranged in a straight line along the axial direction of the discharge pipe 20. Then, the cleaning liquid is supplied obliquely downward from the discharge ports of the pair of discharge pipes 20 and 20 to the inside of the processing tank 10 toward the central direction inside the processing tank 10.

  A plurality of ultrasonic vibration plates (ultrasonic transducers) 22 are attached to the bottom wall outer surface of the propagation tank 14 provided on the bottom wall outer surface of the processing tank 10. As shown in a perspective view in FIG. 2 and a block diagram in FIG. 3, a plurality of ultrasonic diaphragms 22 are arranged in a line along the direction of arrangement of the substrates W, and eight in the illustrated example, Eight ultrasonic diaphragms 22 are arranged in a plurality of rows in the direction orthogonal to the arrangement direction of the substrates W, in the illustrated example, eight rows. Then, eight ultrasonic vibration plates 22 arranged in a line along the arrangement direction of the substrates W are grouped together to form eight ultrasonic transducer groups 22a to 22h, and each ultrasonic transducer is formed. All the ultrasonic diaphragms 22 are connected to one ultrasonic oscillator 26 through a separate delay circuit 24 for each of the groups 22a to 22h. FIG. 3 shows only a configuration in which eight ultrasonic diaphragms 22 belonging to one ultrasonic transducer group 22a are connected to the ultrasonic oscillator 26 via a delay circuit 24a. Similarly, the ultrasonic transducer groups 22b to 22h are connected to the ultrasonic oscillator 26 via the delay circuit 24, respectively. As the ultrasonic oscillator 26, a pulse oscillator that oscillates a pulse wave is used. Then, a vibrator driving oscillation signal having a high frequency, for example, a frequency of 1 MHz or higher is output from the ultrasonic oscillator 26, and the ultrasonic vibration plate 22 vibrates at a high frequency, whereby ultrasonic vibration is generated in the ultrasonic vibration plate 22. . In this embodiment, eight ultrasonic diaphragms 22 arranged in a line along the arrangement direction of the substrates W are grouped and connected to the ultrasonic oscillator 26 via a delay circuit 24. The ultrasonic transducer groups 22a to 22h may be replaced with one ultrasonic diaphragm extending along the arrangement direction of the substrates W.

Next, a control example of the ultrasonic transducer groups 22a to 22h will be described.
FIG. 4 is a diagram illustrating the vibration waveforms of the ultrasonic waves a to h irradiated from the ultrasonic transducer groups 22a to 22h to the inside of the processing tank 10. FIG. When the pulse voltage is applied from the ultrasonic oscillator 26 to the ultrasonic transducer groups 22a to 22h, the ultrasonic transducer groups 22a to 22h vibrate in accordance with the delay times set by the delay circuits 24, respectively. In this example, first, the pair of ultrasonic transducer groups 22d and 22e at the center is pulse-vibrated, and the pair of ultrasonic transducer groups 22c and 22f on both sides is pulse-vibrated with a delay of Δt ₁ from the pulse vibration. The next adjacent ultrasonic transducer groups 22b and 22g are further delayed by Δt ₂ from the vibration, and the next adjacent ultrasonic transducer groups are further delayed by Δt ₃ from the pulse vibration, that is, left and right. The ultrasonic transducer groups 22a and 22h arranged at both ends undergo pulse vibration. And each ultrasonic transducer | vibrator group 22a-22h repeats a pulse vibration with the period of T. FIG. Note that Δt ₁ , Δt ₂ , and Δt ₃ (also Δt described later) are on the order of msec. FIG. 5 is a schematic cross-sectional view showing how the ultrasonic vibration wave irradiated toward the inside of the processing tank 10 propagates through the cleaning liquid.

  In FIG. 5, the wave fronts of the individual ultrasonic vibration waves irradiated from the ultrasonic transducer groups 22a to 22h are denoted by reference numerals 28a to 28h. The wavefronts 28a to 28h of these individual ultrasonic vibration waves are synthesized to form an arcuate synthetic wavefront 30 that opens downward, and the synthetic wavefront 30 advances toward the upper portion of the treatment tank 10 in the cleaning liquid. To go. Therefore, the ultrasonic wave apparently propagates in a direction inclined with respect to the vertical direction as indicated by a solid arrow A in FIG. An ultrasonic wave acts on the left and right holding portions 18, 18 of the support in an oblique direction. As a result, it is possible to minimize the occurrence of a shadow portion on the back side of the holding part 18 of the substrate holder with respect to the traveling direction of the ultrasonic wave, and the uniformity of the cleaning effect is enhanced.

  Further, the cleaning liquid supplied obliquely downward from the pair of discharge ports 20, 20 provided in the vicinity of the bottom of the processing tank 10 toward the central direction inside the processing tank 10 is shown by a broken line arrow B in FIG. 5. Next, it rises symmetrically from the bottom to the top of the treatment tank 10. The upward flow at this time is substantially linear at the center of the processing tank 10, but is greatly curved outward as it goes from the center of the processing tank 10 to the left and right sides. In this case, when ultrasonic waves are irradiated from the ultrasonic transducer groups 22a to 22h in the same phase, the straight ultrasonic vibration waves form a horizontal wavefront and straight in the cleaning liquid toward the upper portion of the processing tank 10. Proceed to. For this reason, the traveling wave of the ultrasonic wave obstructs the flow of the cleaning liquid on the surface of the substrate W, resulting in a liquid pool, and the plurality of substrates W or the entire surface of the substrate W cannot be cleaned uniformly. Therefore, as in this embodiment, the delay time by the delay circuit 24 is set so that the synthetic wavefront 30 of the ultrasonic wave is formed and progresses in accordance with the transition state of the flow distribution of the cleaning liquid in the treatment tank 10. Thus, the cleaning effect of the substrate W can be enhanced.

The delay time Delta] t _1, Delta] t _2, when changing the Delta] t _3, it is possible to change the ultrasonic shape of combined wavefront 30, the delay time in the middle of the cleaning Delta] t _1, Delta] t _2, the value of Delta] t ₃ By changing the inclination, the inclination of the ultrasonic wave acting on the holding part 18 of the substrate support can be changed. Thereby, the shadowed portion generated on the back side of the holding part 18 of the substrate holder changes with respect to the traveling direction of the ultrasonic wave. As a result, it is possible to reduce the area of the portion that is always shadowed with respect to the traveling direction of the ultrasonic wave, and to improve the uniformity of the cleaning effect. Moreover, you may make it irradiate an ultrasonic wave from the ultrasonic transducer | vibrator groups 22a-22h in the same phase suitably in the middle of a washing process. At this time, the combined wavefront of the ultrasonic waves travels upward in the cleaning liquid in the treatment tank 10 in a horizontal plane (see FIG. 8B), and in combination with the ultrasonic irradiation mode described above. Further, the uniformity of the cleaning effect can be further improved. In FIG. 5 (also in FIG. 8 described later), the propagation tank is not shown, but the above-described effect of the present invention can be obtained regardless of the presence or absence of the propagation tank.

  FIG. 6 shows another embodiment of the present invention, and is a diagram showing the vibration waveforms of ultrasonic waves a to h irradiated from the ultrasonic transducer groups 22a to 22h to the inside of the processing tank 10, respectively. In the example shown in FIG. 6, when a pulse voltage is applied to the ultrasonic transducer groups 22a to 22h from the ultrasonic oscillator 26 via the delay circuits 24, first, the ultrasonic transducer groups 22a to 22h According to the arrangement order, pulse vibration is sequentially delayed from the ultrasonic transducer group 22a at one end by Δt (with the phase delayed by Δt). And each ultrasonic transducer | vibrator group 22a-22h repeats a pulse vibration with the period of T. FIG. FIG. 7 and FIG. 8A are schematic cross-sectional views showing how the ultrasonic vibration wave irradiated toward the inside of the treatment tank 10 propagates through the cleaning liquid. As shown in FIG. 7, the wavefronts 32 a to 32 h of the individual ultrasonic vibration waves irradiated from the ultrasonic transducer groups 22 a to 22 h toward the inside of the processing tank 10 are combined to obtain the arrangement direction of the plurality of substrates W. A linear synthetic wavefront 34 inclined downward to the right with respect to the horizontal plane in the orthogonal direction is formed, and the synthetic wavefront 34 advances in the cleaning liquid toward the upper portion of the treatment tank 10. For this reason, the ultrasonic wave apparently propagates in an oblique direction as indicated by a white arrow C in FIG. 7, and the ultrasonic wave acts in an oblique direction on the holding parts 18 and 20 of the substrate support. It becomes.

  Next, switching is performed so that ultrasonic waves are irradiated from the ultrasonic transducer groups 22a to 22h in the same phase. As a result, the ultrasonic transducer groups 22a to 22h vibrate in synchronization with each other. FIG. 8B is a schematic cross-sectional view schematically showing how the ultrasonic vibration wave irradiated toward the inside of the treatment tank 10 at this time propagates through the cleaning liquid. As shown in the figure, the wavefronts of the individual ultrasonic vibration waves irradiated from the ultrasonic transducer groups 22a to 22h toward the inside of the treatment tank 10 are combined to form a combined wavefront 36 that forms a horizontal plane, The synthetic wavefront 36 advances toward the upper part of the processing tank 10 in the cleaning liquid. For this reason, the ultrasonic wave acts directly on the holding portions 18 and 20 of the substrate support.

  Subsequently, the ultrasonic transducer groups 22a to 22h are switched so as to irradiate ultrasonic waves in the order opposite to the order described above. That is, the ultrasonic transducer groups 22a to 22h are sequentially delayed by Δt from the ultrasonic transducer group 22h on the other end side according to the arrangement order (the phase is advanced by Δt sequentially from the ultrasonic transducer group 22a on the one end side). Switch to pulse vibration. And each ultrasonic transducer | vibrator group 22a-22h repeats a pulse vibration with the period of T. FIG. 8C is a schematic cross-sectional view schematically showing how the ultrasonic vibration wave irradiated toward the inside of the processing bath 10 at this time propagates through the cleaning liquid. As shown in the figure, the wavefronts of the individual ultrasonic vibration waves irradiated from the ultrasonic transducer groups 22a to 22h toward the inside of the processing tank 10 are synthesized, and in a direction orthogonal to the arrangement direction of the plurality of substrates W. A linear synthetic wavefront 38 inclined downward to the left with respect to the horizontal plane is formed, and the synthetic wavefront 38 advances toward the upper part of the treatment tank 10 in the cleaning liquid. For this reason, the ultrasonic wave apparently propagates in an oblique direction opposite to the direction shown in FIG. 8A, and the ultrasonic wave is obliquely directed with respect to the holding portions 18 and 20 of the substrate support. Will act. As described above, when the traveling direction of the synthetic wavefronts 34, 36, and 38 of the ultrasonic waves is changed, the shadow generated on the back side of the holding portions 18 and 20 of the substrate holder with respect to the traveling direction of the ultrasonic waves Since the part to be changed changes, the area of the part which is always a shadow becomes small. For this reason, ultrasonic waves are effectively applied to the entire cleaning surface of the substrate W, and the uniformity of the cleaning effect is increased.

  The three ultrasonic irradiation modes described above are repeated as necessary. For example, the mode shown in (a) of FIG. 8 and the mode shown in (c) intervene the mode shown in (b). Repeated alternately. In addition, without irradiating ultrasonic waves from the ultrasonic transducer groups 22a to 22h in the same phase, only the mode shown in (a) of FIG. 8 and the mode shown in (c) are performed, or These two modes may be alternately repeated. Further, when the delay time Δt is changed, for example, when the delay time Δt is increased, the inclination angle of the ultrasonic wavefronts 34 and 38 is increased, and when the delay time Δt is decreased, the inclination angle of the ultrasonic wavefronts 34 and 38 is increased. Therefore, by changing the value of the delay time Δt during the cleaning process, the inclination of the ultrasonic wave acting on the holding parts 18 and 20 of the substrate support may be changed. As a result, the shadowed portion generated on the back side of the holding parts 18 and 20 of the substrate holder changes with respect to the traveling direction of the ultrasonic wave. As a result, the uniformity of the cleaning effect is further increased.

1 is a schematic cross-sectional view illustrating a schematic configuration of a substrate processing apparatus for ultrasonically cleaning a substrate according to an embodiment of the present invention. It is a perspective view which shows the external appearance of the substrate processing apparatus shown in FIG. FIG. 2 is a block diagram showing a schematic configuration of a control system of the substrate processing apparatus shown in FIG. 1. It is a figure which shows an example of the vibration waveform of the ultrasonic wave irradiated to the inside of a processing tank from an ultrasonic transducer | vibrator group when ultrasonically cleaning a board | substrate using the substrate processing apparatus shown in FIG. When the substrate is ultrasonically cleaned using the substrate processing apparatus shown in FIG. 1, the ultrasonic vibration wave irradiated toward the inside of the processing tank in the mode shown in FIG. 4 propagates in the cleaning liquid. It is sectional drawing which shows this typically. It is a figure which shows another example of the vibration waveform of the ultrasonic wave irradiated to the inside of a processing tank from an ultrasonic transducer | vibrator group when ultrasonically cleaning a board | substrate using the substrate processing apparatus shown in FIG. When the substrate is ultrasonically cleaned using the substrate processing apparatus shown in FIG. 1, the ultrasonic vibration wave irradiated toward the inside of the processing tank in the mode shown in FIG. 6 propagates in the cleaning liquid. It is sectional drawing which shows this typically. When the substrate is ultrasonically cleaned using the substrate processing apparatus shown in FIG. 1, the ultrasonic vibration wave irradiated toward the inside of the processing tank in the mode shown in FIG. 6 propagates in the cleaning liquid. It is sectional drawing which shows each typically. It is typical sectional drawing which shows an example of schematic structure of the conventional batch type ultrasonic cleaning apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Processing tank 14 Propagation tank 16,18 Substrate holder holding part 20 Discharge pipe 22 Ultrasonic vibration plate 22a-22h Ultrasonic transducer group 24, 24a Delay circuit 26 Ultrasonic oscillator 28a-28h, 32a-32h Ultrasonic vibration Wave front 30, 34, 36, 38 Composite wave front W substrate

Claims (14)

A plurality of substrates that are supported by the holding portions of the substrate holding means and are arranged in parallel and horizontally in a vertical posture are held in the processing tank, and the plurality of substrates are arranged near the bottom of the processing tank. While supplying the cleaning liquid from the cleaning liquid supply means disposed along the arrangement direction toward the inside of the processing tank, ultrasonic waves are applied from the bottom side of the processing tank to the plurality of substrates held by the substrate holding means. In the substrate processing method of irradiating and cleaning a plurality of substrates,
When the cleaning liquid supplied from the cleaning liquid supply means diffuses into the cleaning liquid in the processing tank, the transition state of the flow distribution in the cross section perpendicular to the arrangement direction of the plurality of substrates, and the bottom of the processing tank When the ultrasonic wave irradiated from the side propagates through the cleaning liquid in the processing tank, the progress of the synthetic wavefront in the cross section orthogonal to the arrangement direction of the plurality of substrates is mutually compatible. A substrate processing method comprising irradiating ultrasonic waves with a phase shifted from a plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers arranged in parallel in a direction orthogonal to the arrangement direction of the plurality of substrates. The substrate processing method according to claim 1,
Supplying the cleaning liquid from the pair of cleaning liquid supply means disposed symmetrically on both sides in the vicinity of the bottom of the processing tank, respectively, symmetrically and obliquely downward toward the central direction inside the processing tank,
The phase of ultrasonic waves emitted from a plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers arranged side by side in the left-right symmetry is determined between the ultrasonic transducer groups or ultrasonic transducers at the left-right symmetrical positions. The ultrasonic transducer groups or ultrasonic transducers that are in the same position and away from the ultrasonic transducer group or ultrasonic transducer in the central position in the direction orthogonal to the arrangement direction of the plurality of substrates are sequentially A substrate processing method characterized by delaying. A plurality of substrates that are supported by the holding portions of the substrate holding means and are arranged in parallel and horizontally in a vertical posture are held in the processing tank, and the plurality of substrates are arranged near the bottom of the processing tank. While supplying the cleaning liquid from the cleaning liquid supply means disposed along the arrangement direction toward the inside of the processing tank, ultrasonic waves are applied from the bottom side of the processing tank to the plurality of substrates held by the substrate holding means. In the substrate processing method of irradiating and cleaning a plurality of substrates,
The ultrasonic waves are respectively emitted from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers arranged in parallel in the direction orthogonal to the arrangement direction of the plurality of substrates, according to the arrangement order of the ultrasonic transducer groups or the ultrasonic transducers. A first step of sequentially irradiating with a phase delay;
A second step of irradiating ultrasonic waves respectively from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers with the phase being sequentially advanced according to the arrangement order of the ultrasonic transducer groups or the ultrasonic transducers;
A substrate processing method comprising: The substrate processing method according to claim 3,
The substrate processing method, wherein the first step and the second step are alternately repeated. The substrate processing method according to claim 3,
A substrate processing method, further comprising a third step of irradiating ultrasonic waves from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers in the same phase. The substrate processing method according to claim 5,
The substrate processing method, wherein the first step and the second step are alternately repeated with the third step interposed. A treatment tank for storing the cleaning liquid;
Substrate holding means for holding the plurality of substrates in the processing tank in a state where the lower ends thereof are supported by the holding unit and arranged in parallel and in the horizontal direction in a vertical posture;
A cleaning liquid supply means that is disposed in the vicinity of the bottom of the processing tank along the arrangement direction of the plurality of substrates held by the substrate holding means, and discharges the cleaning liquid toward the inside of the processing tank;
Ultrasonic irradiation means for irradiating ultrasonic waves from the bottom side of the processing tank to the plurality of substrates held by the substrate holding means;
A substrate processing apparatus for cleaning a plurality of substrates held by the substrate holding means,
A plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers arranged in parallel in a direction orthogonal to the arrangement direction of the plurality of substrates;
An ultrasonic oscillator connected to the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers;
When the cleaning liquid supplied from the processing liquid supply means diffuses into the cleaning liquid in the processing tank, the transition state of the flow distribution in the cross section orthogonal to the arrangement direction of the plurality of substrates, When the ultrasonic wave irradiated from the bottom side propagates in the cleaning liquid in the processing tank, the progress of the composite wavefront in the cross section orthogonal to the arrangement direction of the plurality of substrates is adapted to each other. A control circuit for controlling to shift the phase of the oscillation wave sent from the ultrasonic oscillator to the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers, respectively;
A substrate processing apparatus comprising: The substrate processing apparatus according to claim 7,
A pair of the cleaning liquid supply means are provided symmetrically on both sides in the vicinity of the bottom of the processing tank, and the cleaning liquid is supplied from the pair of cleaning liquid supply means symmetrically and obliquely downward toward the central direction inside the processing tank. And
The plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers are arranged symmetrically,
By the control circuit, the phases of the ultrasonic waves irradiated from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers are matched between the ultrasonic transducer groups or the ultrasonic transducers at the left and right symmetrical positions. In addition, the ultrasonic transducer group or the ultrasonic transducer located at a position farther from the ultrasonic transducer group or the ultrasonic transducer located at the center position in the direction orthogonal to the arrangement direction of the plurality of substrates is sequentially delayed. The substrate processing apparatus is characterized by being controlled as described above. A treatment tank for storing the cleaning liquid;
Substrate holding means for holding the plurality of substrates in the processing tank in a state where the lower ends thereof are supported by the holding unit and arranged in parallel and in the horizontal direction in a vertical posture;
A cleaning liquid supply means that is disposed in the vicinity of the bottom of the processing tank along the arrangement direction of the plurality of substrates held by the substrate holding means, and discharges the cleaning liquid toward the inside of the processing tank;
Ultrasonic irradiation means for irradiating ultrasonic waves from the bottom side of the processing tank to the plurality of substrates held by the substrate holding means;
A substrate processing apparatus for cleaning a plurality of substrates held by the substrate holding means,
A plurality of ultrasonic transducer groups or a plurality of ultrasonic transducers arranged in parallel in a direction perpendicular to the arrangement direction of the plurality of substrates;
An ultrasonic oscillator connected to the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers;
A first state in which ultrasonic waves are respectively emitted from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers while being sequentially delayed in phase according to the arrangement order of the ultrasonic transducer groups or the ultrasonic transducers; Control is performed so as to switch between a second state in which ultrasonic waves are sequentially advanced in accordance with the arrangement order of the ultrasonic transducer groups or ultrasonic transducers from the ultrasonic transducer group or a plurality of ultrasonic transducers. A control circuit to
A substrate processing apparatus comprising: The substrate processing apparatus according to claim 9,
The substrate processing apparatus, wherein the control circuit controls the first state and the second state to be alternately repeated. The substrate processing apparatus according to claim 9,
The control circuit selects between the third state, the first state, and the second state in which ultrasonic waves are emitted from the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers in the same phase. The substrate processing apparatus is controlled to be switched automatically. The substrate processing apparatus according to claim 11, wherein
The substrate processing apparatus, wherein the control circuit performs control so that the first state and the second state are alternately repeated with the third state interposed therebetween. The substrate processing apparatus according to any one of claims 7 to 12,
The substrate processing apparatus, wherein the ultrasonic oscillator is a pulse oscillator that oscillates a pulse wave. The substrate processing apparatus according to claim 7, wherein:
The substrate processing apparatus, wherein the control circuit includes a plurality of delay circuits interposed between the ultrasonic oscillator and the plurality of ultrasonic transducer groups or the plurality of ultrasonic transducers.

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