JP2005296868A - Ultrasonic cleaning method and its apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic cleaning method and its apparatus, by which damage to an object to be cleaned can be suppressed and cleaning efficiency can be improved. <P>SOLUTION: The ultrasonic cleaning method comprises the steps of immersing an wafer W, which is an object to be cleaned, in pure water, which is a cleaning liquid supplied within a cleaning tank 1 and irradiating the cleaning liquid with an ultrasonic wave, so as to clean the wafer W. Pure water is supplied together with N2 gas into the cleaning tank 1 from the outside thereof. At this time, damage to the wafer W can be suppressed and cleaning efficiency can be improved by controlling the flow rate of N2 gas to be supplied with respect to the flow rate of pure water to be supplied. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ultrasonic cleaning method and apparatus for cleaning an object to be processed such as a semiconductor wafer or a glass substrate for LCD using ultrasonic waves.

  In general, in a manufacturing process of a semiconductor manufacturing apparatus, a cleaning processing method is widely adopted in which a semiconductor wafer, a glass substrate for LCD, and the like are sequentially immersed in a cleaning tank in which a cleaning solution such as a chemical solution or a rinsing solution is stored for cleaning. .

  An ultrasonic cleaning process is used as an example of a cleaning process that implements such a cleaning process. According to this ultrasonic cleaning process, a cleaning liquid is supplied into a cleaning tank that accommodates an object to be processed such as a semiconductor wafer (hereinafter referred to as a wafer), and the cleaning liquid for immersing the wafer is irradiated with ultrasonic waves to clean the wafer. be able to.

  In order to enhance the cleaning effect, there is also known a method of cleaning a wafer by providing a gas dissolving means in the cleaning liquid supply system and dissolving the gas in the cleaning liquid (for example, see Patent Document 1).

  According to this method, by performing ultrasonic cleaning by dissolving gas in the cleaning liquid, cavitation is generated during cleaning, and cleaning efficiency can be improved.

As another ultrasonic cleaning method, there is also known a technique for preventing generation of cleaning unevenness and occurrence of damage by sending gas during ultrasonic cleaning to generate bubbles ( For example, Patent Document 2).
Japanese Patent No. 2821887 (Claims, Fig. 1) JP-A 64-4285 (Claims, Fig. 1)

  By the way, in recent years, there is a trend toward miniaturization of wiring patterns, and it is necessary to suppress damage to the wafer due to ultrasonic vibration when performing ultrasonic cleaning processing for cleaning a wafer in which such wiring pattern is miniaturized. There is.

  In order to solve the above problem, it is conceivable to reduce the output of the ultrasonic oscillating means. However, if the output of the ultrasonic oscillating means is reduced, the removal efficiency of particles adhering to the wafer is lowered and the cleaning efficiency is lowered. There is a problem.

  Further, in the technique described in the former, ie, Japanese Patent No. 2821887, there is a problem that cavitation is generated at the time of cleaning by dissolving the gas in the cleaning liquid and performing ultrasonic cleaning, thereby increasing the damage to the wafer. . In the latter technique, that is, in the technique described in Japanese Patent Application Laid-Open No. 64-4285, since the bubble generating portion disposed in the cleaning tank is located between the wafer and the ultrasonic vibrator, ultrasonic vibration is generated in the cleaning tank. There is a problem in that it cannot be uniformly transmitted to the whole and the processing cannot be made uniform.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ultrasonic cleaning processing method and apparatus capable of suppressing damage to an object to be processed and improving cleaning efficiency. Is.

  In order to solve the above-mentioned problem, the ultrasonic cleaning method of the present invention is to immerse the object in the cleaning liquid supplied into the cleaning tank and irradiate the cleaning liquid with ultrasonic waves to clean the object to be processed. In the ultrasonic cleaning method, bubbles are generated by supplying gas together with the cleaning liquid into the cleaning tank from the outside of the cleaning tank, and at this time, the gas supply flow rate with respect to the cleaning liquid supply flow rate can be controlled. (Claim 1). As the gas used in the present invention, for example, nitrogen (N 2) gas or clean air can be used.

  2. The ultrasonic cleaning method according to claim 1, wherein the gas supply flow rate with respect to the cleaning liquid supply flow rate is controlled to 1/60 or more, preferably 1/60 to 2/75. (Claims 2 and 3).

  Further, it is better to supply the cleaning liquid and the gas to the cleaning tank using separate supply pipes (claim 4).

  It is preferable that a plurality of the objects to be processed are arranged in a row at an appropriate interval, and the cleaning liquid and gas are supplied between the objects to be processed.

  The ultrasonic cleaning apparatus of the present invention is an ultrasonic cleaning apparatus for cleaning a target object by immersing the target object in a cleaning liquid supplied into a cleaning tank and irradiating the cleaning liquid with ultrasonic waves. A flow rate of the cleaning liquid provided in a lower portion of the side wall of the cleaning tank and provided in a supply pipe for supplying the cleaning liquid and the gas into the cleaning tank, and connecting a supply pipe connecting the supply means, the cleaning liquid supply source, and the gas supply source. And adjusting means for controlling both the flow rate adjusting means so as to control the flow rate of the gas with respect to the flow rate of the cleaning liquid (Claim 6).

  In the ultrasonic cleaning apparatus of the present invention, the control means is preferably formed so that the flow rate of the gas with respect to the flow rate of the cleaning liquid can be controlled to 1/60 or more, preferably 1/60 to 2/75. 7, 8).

  The invention according to claim 9 is the ultrasonic cleaning apparatus according to any one of claims 6 to 8, wherein the plurality of objects to be processed are arranged and held at appropriate intervals in the cleaning tank. It further comprises holding means to be arranged, and is formed such that a cleaning liquid and a gas can be supplied between the objects to be processed held by the holding means from the supply means.

  The ultrasonic cleaning apparatus according to any one of claims 6 to 9, wherein the supply means includes a cleaning liquid supply nozzle connected to a cleaning liquid supply source via a flow rate control means, And a gas supply nozzle connected to the gas supply source via a flow rate control means. In this case, it is preferable that the cleaning liquid supply nozzle and the gas supply nozzle are respectively disposed in opposing portions of the cleaning tank (Claim 11), and the cleaning liquid supply nozzle and the gas supply nozzle are positioned close to each other in the vertical direction. It is preferable to dispose (claim 12).

  The cleaning liquid supply nozzle and the gas supply nozzle are each formed by a pipe member having a nozzle hole formed at an appropriate interval along the longitudinal direction, and the gas supply is provided in the pipe member forming the cleaning liquid supply nozzle. You may insert the pipe member which forms a nozzle (Claim 13).

  The ultrasonic cleaning apparatus according to any one of claims 6 to 9, wherein the supply means includes a cleaning liquid supply nozzle connected to a cleaning flow supply source via a flow rate control means. The cleaning liquid supply pipe connecting the cleaning liquid supply nozzle and the cleaning liquid supply source includes a gas supply source connected via a flow rate control means.

  (1) According to the invention described in claims 1 to 4, 6 to 8, 10, and 14, gas is supplied together with the cleaning liquid from the outside of the cleaning tank to the cleaning tank at the time of ultrasonic cleaning, and at this time, a predetermined flow rate Ratio (for example, by supplying the flow rate of the gas with respect to the flow rate of the cleaning liquid at 1/60 or more, preferably 1/60 to 2/75, the cleaning liquid in a state where bubbles are generated can be irradiated with ultrasonic waves. Therefore, effective cavitation for cleaning can be generated with a small ultrasonic output, so that damage to the object to be processed can be suppressed and cleaning efficiency can be improved.

  (2) According to the inventions of claims 5 and 9, a plurality of objects to be processed are arranged in a row at an appropriate interval, and a cleaning liquid is supplied between the objects to be processed. The object to be processed can be efficiently cleaned.

  (3) According to the invention described in claims 11 and 12, the cleaning liquid supply nozzle and the gas supply nozzle are respectively disposed in the opposing portions of the cleaning tank, thereby blocking between the object to be processed and the ultrasonic transducer. Since there is nothing, vibration can be transmitted uniformly to the entire cleaning tank, and the object to be processed can be uniformly cleaned, so that the cleaning efficiency can be further improved in addition to the above (1) and (2). .

  (4) According to the invention of the thirteenth aspect, the cleaning liquid supply nozzle and the gas supply nozzle are each formed by the pipe member having the nozzle holes formed at appropriate intervals along the longitudinal direction. A cleaning liquid can be supplied between the objects to be processed, and a plurality of objects to be processed can be simultaneously cleaned. Further, since the pipe member forming the gas supply nozzle is inserted into the pipe member forming the cleaning liquid supply nozzle, the cleaning liquid and gas supply means can be reduced, and the apparatus can be miniaturized.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best embodiment of the present invention will be described in detail with reference to the accompanying drawings. Here, the case where the ultrasonic cleaning apparatus according to the present invention is applied to a semiconductor wafer cleaning apparatus will be described.

<First Embodiment>
FIG. 1 is a schematic sectional view showing a first embodiment of an ultrasonic cleaning processing apparatus (hereinafter referred to as a cleaning processing apparatus) according to the present invention, and FIG. 2 is a schematic plan view thereof.

  The cleaning processing apparatus appropriately separates a cleaning tank 1 in which a cleaning liquid, such as pure water (DIW), into which an object to be processed such as a semiconductor wafer W (hereinafter referred to as a wafer W) is stored, and a plurality of, for example, 50 wafers W. The wafer boat 2 is a holding means that is arranged vertically and held in the cleaning tank 1 and the cleaning liquid L in the cleaning tank 1 is irradiated with ultrasonic waves, that is, for applying ultrasonic vibration. The ultrasonic wave oscillating means 3 and pure water and gas, for example, N 2 gas supply means 4 disposed at opposing positions in the lower portion of the side wall of the cleaning tank 1 are provided.

  The cleaning tank 1 includes an inner tank 1a formed of a chemical-resistant material, for example, a quartz material, and an outer tank 1b that receives the cleaning liquid L that overflows (overflows) from the upper end opening of the inner tank 1a. Has been.

  As shown in FIGS. 1 and 2, the wafer boat 2 includes a plurality of, for example, 50 wafers W, which are parallel to each other and have a plurality of holding grooves (not shown) for holding the wafers W vertically in the horizontal direction. The holding rod 2a and a vertical portion 2b that rises vertically from one end of the holding rod 2a. The vertical portion 2b is moved up and down by an elevating mechanism (not shown), and a plurality of pieces are held by the wafer boat 2, for example Fifty wafers W are soaked in pure water in the cleaning tank 1 or carried out from the cleaning tank 1 upward.

  The ultrasonic oscillating means 3 includes a vibrator 31 mounted on the bottom surface of the bottom of the cleaning tank 1, an ultrasonic oscillator 34 interposed between the vibrator 31 and the high frequency driving power source 32, and a drive switching means. 33, and the drive switching means 33 is configured to selectively drive the vibrator 31.

  When the vibrator 31 of the ultrasonic wave oscillating means 3 configured as described above vibrates, this vibration is propagated to the pure water stored in the cleaning tank 1 and is irradiated with ultrasonic waves.

  The supply means 4 includes a pure water supply nozzle 10 which is a cleaning liquid supply nozzle provided at the lower end portion of the side wall of the cleaning tank 1, and a gas supply nozzle provided at a close position above the pure water supply nozzle 10. The N2 supply nozzle 20 is provided. In this case, the pure water supply nozzle 10 and the N2 supply nozzle 20 are formed by a pipe member 40 having nozzle holes 30 formed at appropriate intervals, as shown by the pure water supply nozzle 10 in FIG. Yes. In this case, the pitch p of the nozzle holes 30 is provided in accordance with the pitch between the wafers W held by the wafer boat 2 so that pure water discharged from the nozzle holes 30 is supplied between the wafers W. It has become. Thereby, the pure water discharged from the nozzle hole 30 can be prevented from directly hitting the wafer W, damage to the wafer W can be suppressed, and particles adhering to the surface of the wafer W can be efficiently removed. it can.

  The pure water supply nozzle 10 is connected to a pure water supply source 14 which is a cleaning liquid supply source via a pure water supply pipe 12 which is a cleaning liquid supply pipe. The pure water supply pipe 12 is provided with a flow meter FM1 and an on-off valve V1 as flow rate adjusting means in order from the pure water supply source 14 side. The position of the nozzle hole 30 of the pure water supply nozzle 10 configured as described above, that is, the discharge direction of the pure water is differently discharged depending on the size and arrangement pitch of the wafers W to be processed.

  On the other hand, the N 2 supply nozzle 20 is connected to an N 2 gas supply source 24 that is a gas supply source via a gas supply pipe 22. The gas supply pipe 22 is provided with a regulator R, a flow meter FM2, which is a flow rate adjusting means, an on-off valve V2, and a filter F in that order from the N2 gas supply source 24 side. N2 gas is discharged downward from the N2 supply nozzle 20 configured as described above. The N2 gas discharged downward from the N2 supply nozzle 20 is instantaneously mixed with pure water discharged upward from the pure water supply nozzle 10 located below.

  The flow meters FM1 and FM2 are electrically connected to the CPU 50 as control means, and the ratio of the N2 gas supply flow rate to the pure water supply flow rate is controlled by a control signal from the CPU 50 stored in advance. It has become so. In this case, the ratio of the supply flow rate of N2 gas to the supply flow rate of pure water is set to 1/60 or more, preferably 1/60 to 2/75.

  Next, an operation mode of the ultrasonic cleaning apparatus configured as described above will be described. First, pure water is supplied into the cleaning tank 1 from the pure water supply source 14 and stored so that the wafer W can be immersed therein.

  Next, a plurality of, for example, 50 wafers W held by a wafer transfer means (not shown) are transferred to the wafer boat 2 and the wafers W are immersed in pure water. Thereafter, the ultrasonic oscillator 34 of the ultrasonic oscillating means 3 is driven, and a high frequency power source is applied to the vibrator 31 to excite it, thereby irradiating the pure water stored in the cleaning tank 1 with ultrasonic waves. Simultaneously with this operation, the on-off valves V1 and V2 are opened, and the flow meters FM1 and FM2 are controlled based on a control signal from the CPU 50. For example, the supply flow rate of N2 gas with respect to the supply flow rate of pure water is 1/60 to 2 / The N 2 gas is supplied (discharged) into the cleaning tank 1 together with pure water under the control of 75. At this time, the N2 gas discharged downward from the N2 supply nozzle 20 is instantaneously mixed with the pure water discharged upward from the pure water supply nozzle 10, and the pure water mixed with the N2 gas is irradiated with ultrasonic waves. . Thereby, the drive output of the ultrasonic oscillator 34 can be lowered (for example, 200 W), cavitation effective for cleaning can be generated, and particles and the like attached to the wafer W can be removed.

  Note that pure water and N 2 gas continue to be supplied into the cleaning tank 1 from the pure water supply nozzle 10 and the N 2 supply nozzle 20 even during cleaning. Thus, by supplying pure water and N2 gas as needed, particles and the like that are removed from the wafer W and float on the liquid surface can be effectively discharged to the outside together with the pure water that overflows to the outer tank 1b. Therefore, the pure water (cleaning liquid) in the cleaning tank 1 can be kept clean. The used pure water that has flowed out of the cleaning tank 1 is received by a pan (not shown) disposed below the cleaning tank 1 and drained from a drain pipe (not shown).

  After performing the cleaning process for a predetermined time as described above, the on-off valves V1 and V2 are closed, and the supply of pure water and N2 gas is stopped.

  Thereafter, the wafer boat 2 is raised to transfer the wafer W to above the cleaning tank 1 and deliver the wafer W to a transfer means (not shown).

Second Embodiment
FIG. 3 is a schematic sectional view showing a second embodiment of the ultrasonic cleaning apparatus according to the present invention.

  In the second embodiment, the arrangement of the pure water supply nozzle 10 and the N2 supply nozzle 20 in the first embodiment is reversed. That is, this is a case where the N2 supply nozzle 20 is disposed at the lower end portion of the opposite side wall of the cleaning tank 1 and the pure water supply nozzle 10 is disposed near the upper position of the N2 supply nozzle 20.

  In this case, in the pure water supply nozzle 10, pure water is discharged (supplied) upward or upward and downward according to the size and interval of the wafer W, as in the first embodiment. On the other hand, in the N2 supply nozzle 20, N2 gas is discharged (supplied) from a downward direction to a horizontal range.

  In the second embodiment, the other parts are the same as those in the first embodiment, so the same parts are denoted by the same reference numerals and description thereof is omitted.

  In the second embodiment, as in the first embodiment, during the cleaning, the flow meters FM1 and FM2 are controlled based on a control signal from the CPU 50. For example, the supply flow rate of N2 gas is 1/60 to the supply flow rate of pure water. Controlled to 2/75, N2 gas is supplied (discharged) into the cleaning tank 1 together with pure water. At this time, the N2 gas discharged from the N2 supply nozzle 20 floats upward, mixes with the pure water discharged from the pure water supply nozzle 10 located above, and ultrasonic waves are applied to the pure water in which bubbles are generated. The Thereby, the drive output of the ultrasonic oscillator 34 can be lowered (for example, 200 W), cavitation effective for cleaning can be generated, and particles and the like attached to the wafer W can be removed.

<Third Embodiment>
FIG. 4 is a cross-sectional view (a) of a principal part showing a modification of the pure water supply nozzle and the N2 nozzle in the third embodiment of the ultrasonic cleaning apparatus according to the present invention, and a cross-sectional view (b) of (a). is there.

  The third embodiment is a case where the pure water and N2 gas supply means 4 has a double tube structure. That is, the pure water supply nozzle 10 constituting a part of the supply means 4 is formed by the square pipe member 40A disposed at the lower part of the side wall of the cleaning tank 1, and the pure water supply nozzle 10A is formed. This is a case where the N2 supply nozzle 20A constituting a part is formed by a pipe member 40B inserted at an interval inward of the square pipe member 40A. In this case, the square pipe member 40 </ b> A is attached to a mounting opening 1 c provided on the side wall of the cleaning tank 1 in an air-watertight manner via a packing or a seal member (not shown), and is appropriately disposed on a surface facing the cleaning tank 1. A plurality of nozzle holes 30A are formed at intervals. In addition, a plurality of nozzle holes 30B are formed on the surface of the pipe member 40B forming the N2 supply nozzle 20A on the cleaning tank 1 side at equidistant positions offset from the nozzle holes 30A.

  In the pure water and N2 gas supply means 4 configured as described above, the N2 gas discharged from the nozzle hole 30B of the inner pipe member 40B flows into the square pipe member 40A, and enters the square pipe member 40A. And is discharged together with pure water from the nozzle hole 30A of the square pipe member 40A.

  In the above description, the case where the pipe member forming the pure water supply nozzle 10 is formed by the square pipe member 40A has been described, but it may be formed by a circular pipe member.

  In addition, in 3rd Embodiment, since another part is the same as 1st Embodiment, the same code | symbol is attached | subjected to the same part and description is abbreviate | omitted.

  In the third embodiment, as in the first embodiment, during the cleaning, the flow meters FM1 and FM2 are controlled based on a control signal from the CPU 50. For example, the supply flow rate of N2 gas with respect to the supply flow rate of pure water is 1/60 to Controlled to 2/75, N2 gas is supplied (discharged) into the cleaning tank 1 together with pure water. At this time, the N2 gas discharged from the nozzle hole 30B of the pipe member 40B that forms the N2 supply nozzle 20A flows into the rectangular pipe member 40A that forms the pure water supply nozzle 10, and the pure gas in the square pipe member 40A After being mixed with water, it is supplied (discharged) into the cleaning tank 1 together with pure water from the nozzle hole 30A of the square pipe member 40A, and ultrasonic waves are applied to the pure water in which bubbles are generated by mixing N2 gas. Thereby, the drive output of the ultrasonic oscillator 34 can be lowered (for example, 200 W), cavitation effective for cleaning can be generated, and particles and the like attached to the wafer W can be removed.

<Fourth embodiment>
FIG. 5: is principal part sectional drawing (a) and II line | wire of (a) which shows another modification of the pure water supply nozzle and N2 nozzle in 4th Embodiment of the ultrasonic cleaning processing apparatus which concerns on this invention. It is sectional drawing (b) which follows this.

  As in the third embodiment, the fourth embodiment is a case where the pure water supply nozzle 10 and the N2 supply nozzle 20 forming the pure water and N2 gas supply means 4 have a double pipe structure. The difference is that the rectangular pipe member 40A forming the supply nozzle 10 and the pipe member 40B forming the N2 supply nozzle 20 are integrally formed, and the nozzle holes 30A and 30B are provided on the inner surface side of the cleaning tank 1, respectively. .

  That is, in the fourth embodiment, the double pipe member 40C formed integrally with the square pipe member 40A and the pipe member 40B is replaced with a packing or seal member (not shown) in the mounting opening 1c provided on the side wall of the cleaning tank 1. The nozzle holes 30 </ b> A and 30 </ b> B are provided at appropriate intervals at locations where the square pipe member 40 </ b> A and the pipe member 40 </ b> B face the cleaning tank 1. In this case, the pipe member 40B is provided on the upper side. In addition, the nozzle holes 30A of the square pipe member 40A are provided upward, the nozzle holes 30B of the pipe member 40B are provided downward, and the nozzle holes 30A and 30B are offset from each other and are arranged in a staggered manner as a whole. Yes.

  In addition, in 4th Embodiment, since another part is the same as 1st Embodiment, the same code | symbol is attached | subjected to the same part and description is abbreviate | omitted.

  In the fourth embodiment, as in the first embodiment, during the cleaning, the flow meters FM1 and FM2 are controlled based on a control signal from the CPU 50. For example, the supply flow rate of N2 gas with respect to the supply flow rate of pure water is 1/60 to Controlled to 2/75, N2 gas is supplied (discharged) into the cleaning tank 1 together with pure water. At this time, N2 gas discharged downward from the pipe member 40B forming the N2 supply nozzle 20 is instantaneously mixed with pure water discharged upward from the square pipe member 40A forming the pure water supply nozzle 10, and N2 Ultrasonic waves are applied to pure water in which bubbles are generated by mixing gases. Thereby, the drive output of the ultrasonic oscillator 34 can be lowered (for example, 200 W), cavitation effective for cleaning can be generated, and particles and the like attached to the wafer W can be removed.

<Other embodiments>
In the above embodiment, the case where the pure water and N2 gas supply means 4 is constituted by the pure water supply nozzle 10 and the N2 supply nozzle 20 has been described. However, the supply flow rate of N2 gas with respect to the supply flow rate of pure water is 1 / As long as it can be controlled to 60 to 2/75, as shown in FIG. 6, it is constituted only by the pure water supply nozzle 10, the N2 gas supply pipe 22 is connected to the pure water supply pipe 12, and the pure water supply pipe A structure in which bubbles are generated in 12 and then supplied from the pure water supply nozzle 10 may be used. In FIG. 6, the other parts are the same as those in the first embodiment, so the same parts are denoted by the same reference numerals and the description thereof is omitted.

  In the above embodiment, the ultrasonic cleaning method and apparatus according to the present invention are applied to a semiconductor wafer cleaning process, but the present invention can also be applied to an LCD glass substrate cleaning process.

  Next, damage to the wafer W and particle removal performance will be described.

<Damage to wafer>
When the wafer W having a wiring pattern is irradiated with ultrasonic waves by a conventional ultrasonic cleaning method that does not use N2 gas, if the output of the ultrasonic transmitter 34 (usually about 400 W) is high, the wiring on the wafer W is damaged. Has been confirmed to give. Therefore, it is necessary to perform cleaning with a low output of the ultrasonic transmitter 34. However, if the output of the ultrasonic transmitter 34 is lowered, there arises a problem that the efficiency of removing particles adhering to the wafer W is lowered.

<Particle removal performance>
In order to investigate how the output of the ultrasonic transmitter 34 can be lowered to improve the particle removal efficiency, an experiment was conducted under the following conditions.

  That is, the output of the ultrasonic transmitter 34 was set to 200 W, which is a low output that does not damage the wafer W, and the N2 gas supply flow rate with respect to the pure water supply flow rate 30 L / min was changed to examine the particle removal rate. However, the results shown in FIG. 7 were obtained.

  As a result of the above experiment, when the N2 gas supply flow rate is 500 mL / min or more, that is, when the ratio of the N2 gas supply flow rate to the pure water supply flow rate 30 L / min is 1/60 or more, the particle removal rate is generally a wafer. It was found that it was 85% or more, which was judged as no problem in production. Further, when the N2 gas supply flow rate exceeds 800 mL / min (the ratio of the N2 gas supply flow rate to the pure water supply flow rate of 30 L / min is 2/75), it is found that the particle removal rate is constant at 90%. It was.

  Therefore, considering that the supply flow rate of N2 gas with respect to the supply flow rate of pure water is 1/60 or more and that N2 gas is not consumed much, it is preferable to control the supply flow rate to 1/60 to 2/75. The removal rate of the particles can be increased without giving any.

1 is a schematic cross-sectional view showing a first embodiment of an ultrasonic cleaning processing apparatus according to the present invention. It is a schematic plan view of the said ultrasonic cleaning processing apparatus. It is a schematic sectional drawing which shows 2nd Embodiment of the said ultrasonic cleaning processing apparatus. It is sectional drawing (a) which shows the principal part of 3rd Embodiment of the said ultrasonic cleaning processing apparatus, and the cross-sectional view (b) of (a). It is sectional drawing (b) which follows the II line of (a) and (a) which shows the principal part of 4th Embodiment of the said ultrasonic cleaning apparatus. It is a schematic sectional drawing which shows another embodiment of the said ultrasonic cleaning processing apparatus. It is a graph which shows the relationship between a particle removal rate and N2 gas flow volume.

Explanation of symbols

W Semiconductor wafer (object to be processed)
1 Cleaning tank 2 Wafer boat (holding means)
3 Ultrasonic oscillation means 4 Supply means 10, 10A Pure water supply nozzle 12 Pure water supply pipe (cleaning liquid supply pipe)
14 Pure water supply source (cleaning liquid supply source)
20,20A N2 supply nozzle (gas supply nozzle)
22 Gas supply pipe 24 N2 gas supply source (gas supply source)
30, 30A, 30B Nozzle hole 40, 40A, 40B, 40C Pipe member 50 CPU (control means)
FM1, FM2 flow meter (flow rate adjusting means)

Claims (14)

In the ultrasonic cleaning method of cleaning the target object by immersing the target object in the cleaning liquid supplied into the cleaning tank and irradiating the cleaning liquid with ultrasonic waves,
Bubbles are generated by supplying gas together with the cleaning liquid into the cleaning tank from the outside of the cleaning tank, and at this time, the supply flow rate of the gas with respect to the supply flow rate of the cleaning solution can be controlled. Sonic cleaning method. The ultrasonic cleaning method according to claim 1,
An ultrasonic cleaning method characterized in that the gas supply flow rate with respect to the cleaning liquid supply flow rate can be controlled to 1/60 or more. The ultrasonic cleaning method according to claim 1,
An ultrasonic cleaning method, wherein the gas supply flow rate relative to the cleaning liquid supply flow rate can be controlled to 1/60 to 2/75. In the ultrasonic cleaning processing method according to any one of claims 1 to 3,
An ultrasonic cleaning method, characterized in that the cleaning liquid and the gas are supplied to the cleaning tank using a separate supply pipe. In the ultrasonic cleaning processing method according to any one of claims 1 to 4,
A plurality of the objects to be processed are arranged in rows at appropriate intervals,
An ultrasonic cleaning method, wherein the cleaning liquid and gas are supplied between the objects to be processed. In the ultrasonic cleaning apparatus for irradiating the cleaning object with the cleaning liquid supplied into the cleaning tank and irradiating the cleaning liquid with ultrasonic waves to clean the processing object,
A supply means disposed at a lower portion of the side wall of the cleaning tank, and supplying the cleaning liquid and gas into the cleaning tank;
A cleaning liquid flow rate adjusting means and a gas flow rate adjusting means provided in a supply pipe connecting the supply means to the cleaning liquid supply source and the gas supply source;
An ultrasonic cleaning processing apparatus comprising: control means capable of controlling both of the flow rate adjusting means so as to control the flow rate of the gas with respect to the flow rate of the cleaning liquid. The ultrasonic cleaning apparatus according to claim 6, wherein
The ultrasonic cleaning apparatus according to claim 1, wherein the control means is formed so that the flow rate of the gas with respect to the flow rate of the cleaning liquid can be controlled to 1/60 or more. The ultrasonic cleaning apparatus according to claim 6, wherein
The ultrasonic cleaning apparatus according to claim 1, wherein the cleaning means is formed so that the flow rate of the gas with respect to the flow rate of the cleaning liquid can be controlled to 1/60 to 2/75. The ultrasonic cleaning apparatus according to any one of claims 6 to 8,
It further comprises holding means for arranging and holding a plurality of the above-mentioned objects to be processed in an appropriate interval in a cleaning tank,
An ultrasonic cleaning apparatus characterized in that a cleaning liquid and a gas can be supplied between the object to be processed held by the holding means from the supply means. In the ultrasonic cleaning processing apparatus according to any one of claims 6 to 9,
The ultrasonic cleaning is characterized in that the supply means includes a cleaning liquid supply nozzle connected to the cleaning liquid supply source via the flow rate control means, and a gas supply nozzle connected to the gas supply source via the flow rate control means. Processing equipment. The ultrasonic cleaning apparatus according to claim 10, wherein
An ultrasonic cleaning processing apparatus, wherein the cleaning liquid supply nozzle and the gas supply nozzle are respectively disposed in opposing portions of the cleaning tank. The ultrasonic cleaning apparatus according to claim 10 or 11,
An ultrasonic cleaning processing apparatus, wherein the cleaning liquid supply nozzle and the gas supply nozzle are arranged at positions close to each other in the vertical direction. The ultrasonic cleaning apparatus according to any one of claims 10 to 12,
The cleaning liquid supply nozzle and the gas supply nozzle are each formed by a pipe member having nozzle holes drilled at appropriate intervals along the longitudinal direction, and the gas supply nozzle is disposed in the pipe member forming the cleaning liquid supply nozzle. An ultrasonic cleaning apparatus characterized by interposing a pipe member to be formed. In the ultrasonic cleaning processing apparatus according to any one of claims 6 to 9,
The supply means includes a cleaning liquid supply nozzle connected to the cleaning supply source via the flow control means, and a gas supply source connected to the cleaning liquid supply pipe connecting the cleaning liquid supply nozzle and the cleaning liquid supply source via the flow control means. An ultrasonic cleaning apparatus characterized by comprising:

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