JP2001334221A - Substrate cleaning apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate cleaning apparatus which can completely remove fine particles on the surface of the substrate so that the cleaning action for the surface of the substrate can be improved. SOLUTION: An ultrasonic cleaning head 21 is positioned spaced at an interval D1 i.e., a first interval being a processing position, from the upper surface Wa of a substrate W which is rotated about the axis of rotation R of the substrate W. In the head 21, a vibration surface VF provided in a substrate surface WF imparts ultrasonic wave vibration to a cleaning liquid supplied into a gap K from nozzles 220, 230. A vibration element 213 disposed on a vibration plate 212 constituting the surface VF alternates with split electrodes 252a, 252b in a comb-teeth like form, and phase-deviated alternating-current drive signals are applied to the element 213 to generate traveling waves on the surface VF.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to various substrates such as a semiconductor wafer, a glass substrate for a liquid crystal display, a PDP (plasma display panel) substrate, a glass substrate for a magnetic disk, and a ceramic substrate. The present invention relates to a substrate cleaning apparatus and a substrate cleaning method for performing a cleaning process.

[0002]

2. Description of the Related Art A semiconductor device manufacturing process includes a process of forming a fine pattern by repeatedly performing processes such as film formation and etching on the surface of a semiconductor wafer (hereinafter, simply referred to as "substrate"). . For microfabrication, both sides of the substrate, especially one side of the substrate on which the thin film is formed (thin film forming surface)
It is necessary to keep the substrate clean, and the substrate is subjected to a cleaning process as necessary. For example, a thin film formed on a thin film forming surface of a substrate is subjected to chemical mechanical polishing using an abrasive (hereinafter, referred to as a chemical mechanical polishing process).
After the CMP process, since the abrasive (slurry) remains on both surfaces of the substrate, it is necessary to remove the slurry.

A conventional substrate cleaning apparatus for cleaning a substrate as described above includes, for example, a double-side cleaning apparatus for scrub-cleaning both sides of a substrate while supplying a cleaning liquid to both sides while rotating the substrate, and a rotating apparatus for rotating the substrate. A single-sided cleaning device that scrubs and ultrasonically cleans one surface of the substrate (thin film forming surface) while supplying a cleaning liquid to both surfaces while supplying pure water to both surfaces of the substrate while rotating the substrate, and then washing with water. A water washing / drying device that shakes off moisture on the surface of the substrate by stopping the supply of water and rotating the substrate at high speed to dry the substrate.

[0004] In particular, the above-mentioned single-side cleaning apparatus is mainly used for removing particles stuck to the substrate surface.
A brush cleaning mechanism that scrubs the surface of the substrate with a sponge brush, and an ultrasonic cleaning that supplies a cleaning liquid to which ultrasonic waves are applied toward the surface of the substrate, mainly to remove fine particles remaining on the substrate surface. Mechanisms are provided, and by these mechanisms, fine particles such as dust and slurry adhering to the substrate surface can be removed.

The ultrasonic cleaning mechanism applies ultrasonic waves to the cleaning liquid by a vibration plate that receives a pulse from an ultrasonic oscillator and vibrates ultrasonically, and directs the cleaning liquid to which the ultrasonic waves have been applied toward the substrate surface. An ultrasonic nozzle for discharging is provided, and fine particles are separated from the substrate surface and can be removed by the ultrasonic vibration energy of the cleaning liquid.

[0006] However, with the recent increase in the definition of thin film formation patterns, it has become necessary to remove finer particles. In the above-described ultrasonic cleaning mechanism of the conventional substrate cleaning apparatus, the finer particles have to be removed. There has been a problem that it cannot cope with the removal of particles. That is, in the conventional ultrasonic cleaning mechanism, the distance from the tip of the discharge port of the ultrasonic nozzle to the substrate surface to which the cleaning liquid to which the ultrasonic wave is actually applied is supplied (hereinafter, referred to as discharge distance) is increased. Therefore, there is a problem that the ultrasonic vibration energy applied to the cleaning liquid during this distance is attenuated, and the substrate surface is not sufficiently ultrasonically cleaned, so that finer particles cannot be removed.

In addition, during the above-described discharge distance, air in the atmosphere mixes with the cleaning liquid to form bubbles, and the bubbles also attenuate the ultrasonic vibration energy of the cleaning liquid, so that the substrate surface becomes insufficient. However, there is also a problem that ultrasonic cleaning is not performed and finer particles cannot be removed.

In addition, it is necessary to always supply an appropriate amount of cleaning liquid, and there is a problem that the amount of cleaning liquid is particularly large.

[0009]

To cope with such a situation, Japanese Unexamined Patent Publication No. Hei 11 (1999) discloses an example of an ultrasonic cleaning apparatus capable of greatly reducing the amount of cleaning liquid in an ultrasonic cleaning mechanism and saving liquid.
No. 138116 is provided. In this conventional ultrasonic cleaning apparatus, a liquid film is formed between a substrate and a vibration plate (vibration plate) by the action of surface tension, and ultrasonic waves from the vibration plate are transmitted to the substrate via the liquid film. An arrangement is disclosed. Therefore, the substrate can be cleaned by the action of the liquid film, and the amount of the cleaning liquid used can be reduced.

In the above ultrasonic cleaning apparatus, the ultrasonic cleaning mechanism 110 is formed in such a size that the vibration plate 120 covers the entire substrate W as shown in FIG. Thus, a liquid film is formed between the substrate and the surface of the substrate W that moves in the movement direction F, and the ultrasonic waves are transmitted. Dispersing the ultrasonic waves over a wide area without concentrating the ultrasonic waves in this manner is effective in that the ultrasonic waves are collected at one point and the circuit pattern formed on the substrate is damaged. However, with the recent trend toward higher definition of thin film formation patterns,
There has been a problem that it is not possible to cope with the removal of finer particles. That is, it is desired to increase the cleaning efficiency without concentrating the ultrasonic waves.

In particular, when cleaning the back surface of the substrate, it is necessary to improve the ability to remove particles. However, if the cleaning of the back surface of the substrate is also taken into consideration, it is desired to further increase the cleaning efficiency. .

When the size of the vibration plate 120 increases, the ratio of the cleaning liquid in the gap between the substrate and the substrate increases, and as a result, fine particles such as dust and slurry remain on the surface of the substrate W. This has led to a decrease in yield in the manufacturing process of semiconductor devices, which has become a major problem.

Accordingly, an object of the present invention is to solve the above-mentioned technical problems, and to provide a substrate cleaning apparatus capable of sufficiently removing fine particles on the substrate surface and improving the cleaning power of the substrate surface. It is in.

[0014]

In order to achieve the above object, the present invention provides a vibrating surface opposed to a relatively moving substrate at an interval, and an ultrasonic vibrating surface provided on the vibrating surface. An ultrasonic cleaning unit having a vibrator for generating an ultrasonic wave; and a fluid supply unit for supplying a fluid used for processing the substrate at an interval between a vibrating surface of the ultrasonic cleaning unit and the substrate. The means is a substrate cleaning apparatus, wherein a plurality of divided electrodes respectively receiving different AC drive signals are provided in parallel with the vibrating surface.

According to a second aspect of the present invention, in the substrate cleaning apparatus according to the first aspect, the plurality of divided electrodes are arranged in parallel in the longitudinal direction of the vibrating surface.

According to a third aspect of the present invention, in the substrate cleaning apparatus according to the first or second aspect, substrate rotating means for rotating the substrate in a predetermined rotation direction about a vertical rotation axis; And applying an AC drive signal having a phase shifted in order from the divided electrode closer to the rotation axis of the substrate among the plurality of divided electrodes.

According to a fourth aspect of the present invention, there is provided an ultrasonic cleaning means having a vibrating surface opposed to a relatively moving substrate at an interval, a vibrator for generating ultrasonic vibration on the vibrating surface, A fluid supply unit for supplying a fluid used for processing the substrate, at an interval between the vibration surface of the ultrasonic cleaning unit and the substrate, and the ultrasonic cleaning unit includes the vibrator at one end of the vibration surface. A substrate cleaning apparatus comprising:

According to a fifth aspect of the present invention, in the substrate cleaning apparatus of the fourth aspect, the ultrasonic cleaning means arranges the vibrator at one end in a longitudinal direction of the vibrating surface. I do.

According to a sixth aspect of the present invention, in the substrate cleaning apparatus according to the fourth or fifth aspect, substrate rotating means for rotating the substrate in a predetermined rotation direction about a vertical rotation axis; And the ultrasonic cleaning means is characterized in that the vibrator is disposed on a side of the vibrating surface close to a rotation axis of the substrate.

The operation of the present invention is as follows. Here, according to the substrate cleaning apparatus of the invention according to claim 1, the distance between the substrate that is relatively moved and the vibration surface of the ultrasonic cleaning unit is:
The fluid used for processing the substrate is supplied and filled from the fluid supply unit, and the fluid filled in this interval is subjected to ultrasonic waves by the vibrating surface.

Here, it is required that sufficient cleaning efficiency be obtained over the entire area of the vibrating surface. According to the first aspect of the present invention, by arranging the divided electrodes in parallel with the vibrating surface, a traveling wave of ultrasonic vibration is generated along with normal vibration of the fluid on the vibrating surface. That is, by applying different AC drive signals to each of the divided electrodes, a vibration wave has a different period and a traveling wave is generated. As a result, the fluid supplied between the vibrating surface and the substrate can be moved, and at the same time, the moving particles can efficiently remove fine particles on the substrate surface sufficiently to improve the cleaning power of the substrate surface. Can be done.

Further, the fluid filled in the space facing the substrate is not exposed to the atmosphere and no air such as air bubbles is mixed therein. Therefore, the fluid in the state filled with the above-mentioned space efficiently transmits ultrasonic vibration energy when ultrasonic vibration is applied, so that fine particles on the substrate surface are sufficiently removed, and the substrate is sufficiently removed. The detergency of the surface can be improved.

The “substrate surface” here may be the surface of the substrate on which the thin film is formed, the surface of the substrate on which the thin film is not formed, or the upper and lower surfaces of the substrate. Either may be used. That is, the substrate surface may be any surface excluding the end surface of the peripheral portion of the substrate.

Furthermore, the term "fluid" used herein refers to pure water and chemicals (for example, hydrofluoric acid, sulfuric acid, hydrochloric acid, nitric acid,
Cleaning liquid such as phosphoric acid, acetic acid, ammonia, or an aqueous solution of hydrogen peroxide thereof, or any liquid capable of cleaning the substrate surface.

According to the substrate cleaning apparatus of the second aspect, the divided electrodes are arranged in parallel in the longitudinal direction of the vibrating surface. As a result, the traveling wave acts in the longitudinal direction of the vibration surface, and transmits vibration energy to the fluid for a longer time. As a result, fine particles on the substrate surface can be sufficiently removed, and the detergency of the substrate surface can be improved.

According to a third aspect of the present invention, the substrate cleaning apparatus includes substrate rotating means for rotating the substrate in a predetermined rotation direction about a vertical rotation axis,
An alternating-current drive signal whose phase is shifted in order from the divided electrode closer to the rotation axis of the substrate among the plurality of divided electrodes may be applied. That is, by doing so, the traveling wave is generated in a direction away from the rotation axis of the substrate, in other words, toward the end of the substrate. Therefore, the replacement efficiency is improved without the fluid staying on the substrate surface, and the fluid to which fresh ultrasonic vibration is always applied is in contact with the substrate surface. As a result, the cleaning power of the substrate surface can be further improved.

According to the substrate cleaning apparatus of the invention, the ultrasonic cleaning means has the vibrator at one end of the vibrating surface. As a result, the traveling wave of the ultrasonic vibration can move the fluid on the vibrating surface, and the traveling wave moving on the vibrating surface can efficiently and sufficiently remove fine particles on the substrate surface, thereby cleaning the surface of the substrate. Can be improved.

According to the substrate cleaning apparatus of the invention, the vibrator is provided at one end in the longitudinal direction of the vibrating surface. As a result, the traveling wave of the ultrasonic vibration can move the fluid in the longitudinal direction on the vibration surface, and the traveling energy traveling in the longitudinal direction transmits vibration energy to the fluid longer. As a result, fine particles on the substrate surface can be efficiently and sufficiently removed, and the detergency of the substrate surface can be improved.

According to the sixth aspect of the present invention, in the substrate cleaning apparatus, the vibrator of the ultrasonic cleaning means may be arranged on a side of the vibrating surface close to the rotation axis of the substrate. That is, by doing so, the traveling wave is generated in a direction away from the rotation axis of the substrate, in other words, toward the end of the substrate. Therefore, the efficiency of fluid replacement is improved, and the cleaning liquid to which fresh ultrasonic vibrations are always applied is in contact with the substrate surface, and the cleaning power of the substrate surface can be further improved.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a substrate cleaning apparatus according to an embodiment of the present invention for solving the above technical problems will be described.
This will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing a configuration of a main part of a substrate cleaning apparatus according to an embodiment of the present invention. Note that this substrate cleaning apparatus 1 has a C
After scrubbing both surfaces of the wafer after the MP processing (hereinafter simply referred to as “substrate”) to remove relatively large particles, the upper surface Wa (thin film forming surface) of the substrate W is again scrubbed and ultrasonically cleaned. This is an apparatus for removing relatively fine particles. The substrate W is unloaded or loaded into and out of the substrate cleaning apparatus 1 by suctioning and holding the lower surface Wb of the substrate W (the surface opposite to the thin film forming surface) (FIG. 1).
(See H) indicated by a two-dot chain line).

This substrate cleaning apparatus 1 uses a rotation axis R
Rotating mechanism 10 for rotating the substrate upper surface Wa in the rotation direction F (moving direction), an ultrasonic cleaning mechanism 20 for ultrasonically cleaning the substrate upper surface Wa, a brush cleaning mechanism 30 for scrub cleaning the substrate upper surface Wa, and a substrate An auxiliary liquid supply mechanism 40 that supplies the cleaning liquid toward a point O (the center O of the substrate W) where the upper surface Wa and the rotation axis R of the substrate W intersect, and a control unit 50 that controls the operation of each mechanism. Has become.

The substrate rotating mechanism 10 is provided at the upper end of the spin shaft 11 which receives a rotational driving force from a rotational driving source (not shown) and rotates in the direction of rotation F. And a spin chuck 12 for suction holding by a plurality of suction holes on the upper surface. With these configurations, the substrate rotation mechanism 10 can rotate the substrate W in the direction of the rotation direction F about the rotation axis R perpendicular to the substrate W while holding the substrate lower surface Wb by suction. . The substrate rotating mechanism 10 corresponds to the substrate rotating means of the present invention.

Also, The ultrasonic cleaning mechanism 20 is provided on the upper surface W of the substrate.
a facing surface WF provided so as to oppose a, a nozzle described below that has a tip portion disposed in the substrate facing surface WF and supplies a cleaning liquid such as pure water as a fluid, and a substrate facing surface WF. A vibrating surface (a VF in FIG. 2 described later) that is provided and applies ultrasonic vibration to the cleaning liquid supplied from the nozzle.
, An ultrasonic cleaning head 21 for applying ultrasonic vibration to the cleaning liquid supplied between the substrate facing surface WF and the substrate upper surface Wa, and a swing holding the ultrasonic cleaning head 21 at one end. An arm 22, a swing drive source 24 such as a motor for rotating (swinging) the swing arm 22 within a predetermined angle range around an arm shaft 23, and moving the ultrasonic cleaning head 21 and the swing arm 22 up and down. And a lifting drive source 25 such as a motor for raising and lowering in the direction. The portion of the ultrasonic cleaning mechanism 20 including the ultrasonic cleaning head 21 corresponds to the ultrasonic cleaning means of the present invention.

A swing transmission mechanism 24t for transmitting the rotational driving force from the swing drive source 24 to the swing arm 22 is provided between the swing arm 22 and the swing drive source 24. For example, the swing transmission mechanism 24t includes a set of pulleys attached to the output shaft of the motor as the swing drive source 24 and the arm shaft 23, and a belt stretched between the set of pulleys. Belt and pulley mechanism. Thus, if the output shaft of the motor as the swing drive source 24 is rotated, the arm shaft 23 rotates, and the swing arm 23 rotates.

Between the swing arm 22 and the elevation drive source 25, an elevation transmission mechanism 25t for converting the rotational driving force from the elevation drive source 25 into a vertical drive force and transmitting the same to the oscillation arm 22. Is provided. For example, the lifting transmission mechanism 25t includes a ball screw shaft rotatably connected to an output shaft of a motor serving as the lifting drive source 25 and a structure from the swing arm 22 to the swing drive source 24 that is linearly connected. A ball screw mechanism and the like, which are movably held and include a mover screwed to the ball screw shaft, are provided. Thus, if the output shaft of the motor as the elevation drive source 25 is rotated, the ball screw shaft rotates and the mover moves up and down, and the structure from the swing arm 23 to the swing drive source 24 is formed. Go up and down.

With these configurations, the ultrasonic cleaning mechanism 20
Can move the ultrasonic cleaning head 21 back and forth between the processing position shown in FIG. 1 and the standby position located outside the upper surface Wa of the substrate along the path A2 by the swing drive source 24. 25 makes it possible to move up and down along the routes A1 and A3. That is, the ultrasonic cleaning mechanism 20 moves up the path A1,
Next, the distance between the substrate upper surface Wa and the substrate facing surface WF (hereinafter, referred to as the substrate facing surface WF).
The substrate A is horizontally moved on the path A2 in a direction approaching the rotation axis R of the substrate W while maintaining the state where the substrate facing distance D is the large second distance D2, and then lowered on the path A3. I have. Then, the ultrasonic cleaning head 21 maintains the state of the processing position where the substrate facing distance D is the first distance D1. Similarly, after moving up the path A3 and moving horizontally on the path A2 in a direction away from the rotation axis R of the substrate W, the path A1 is lowered to the standby position.

The brush cleaning mechanism 30 is provided on the substrate upper surface W
a brush portion 31 having a sponge brush for scrubbing a, a swing arm 32 for rotatably holding the brush portion 31 at one end, and a predetermined angle around the arm shaft 33 for the swing arm 32 A swing drive source 34 such as a motor that rotates (swings) in a range, and an elevation drive source 35 such as a motor that vertically moves the brush unit 31 and the swing arm 32 up and down. In addition, the brush part 31
The rotation is made by a rotation drive source such as a motor (not shown) provided in the swing arm 32. Note that between the swing arm 32 and the swing drive source 34 and between the swing arm 32 and the lift drive source 35, a swing transmission mechanism 34t having the same structure as the ultrasonic cleaning mechanism 20 and a lift mechanism A transmission mechanism 35t is provided.

With these structures, the ultrasonic cleaning mechanism 20
Similarly to the above, the brush cleaning mechanism 30 can horizontally move the brush unit 31 along the substrate upper surface Wa by the swing drive source 24, and can vertically move the brush unit 31 by the elevation drive source 25. ing. The brush portion 31 and the ultrasonic cleaning head 21 are positioned at the center O of the substrate W.
Each movement is controlled so as not to interfere in the vicinity.

Further, the auxiliary liquid supply mechanism 40 includes an auxiliary liquid supply nozzle 41 for supplying the cleaning liquid toward the vicinity of the center O of the substrate upper surface Wa, an auxiliary liquid pipe 42 for supplying the cleaning liquid to the auxiliary liquid supply nozzle 41, and And a cleaning liquid supply source 43 to which the auxiliary liquid pipe 42 is connected. Also,
In the middle of the auxiliary liquid pipe 42, an auxiliary liquid supply nozzle 4
A valve 44 for starting / stopping the supply of the auxiliary liquid from 1 is interposed.

It should be noted that the cleaning liquid from the auxiliary liquid supply mechanism 40 is used at least for the ultrasonic cleaning head 2 having a nozzle.
While 1 is not located at the processing position, it is supplied to the center O of the substrate W. Therefore, the entire area of the upper surface Wa of the substrate is always supplied with the cleaning liquid. However,
In order to further prevent the substrate upper surface Wa from drying, it is preferable that the cleaning liquid is always supplied from the auxiliary liquid supply nozzle 41 to the substrate upper surface Wa while the substrate W is held on the spin chuck 12. .

Next, the substrate cleaning apparatus 1 having the above configuration
Will be briefly described. First, in a state where the ultrasonic cleaning head 21 is located at the standby position,
By a hand H of a substrate transfer robot (not shown), a substrate W whose both surfaces have been cleaned in advance is carried into the substrate cleaning apparatus 1, and is placed on the upper surface of the spin chuck 12 and held by suction. Almost simultaneously with the suction and holding of the substrate W by the spin chuck 12, the cleaning liquid is supplied from the liquid supply nozzle 41 of the auxiliary liquid supply mechanism 40 toward the vicinity of the center O of the substrate W.
Next, the spin chuck 12 holding the substrate W by suction is rotated at a high speed by a rotation driving source (not shown), and the substrate W is rotated about the rotation axis R in the rotation direction F (substrate rotation step).

Then, the swing arm 22 is rotated by the swing drive source 24, and the ultrasonic cleaning head 21 of the ultrasonic cleaning mechanism 20 moves above the center O of the substrate W along the paths A1 and A2. Almost at the same time, the ultrasonic cleaning mechanism 2
The cleaning liquid is supplied from the nozzle No. 0 (cleaning liquid supply step).

Next, the swing arm 22 is moved down along the path A3 by the elevation drive source 25, and the ultrasonic cleaning head 21 is brought close to the substrate upper surface Wa near the center O of the substrate W.
Ultrasonic cleaning is performed at the processing position at the first interval D1 (ultrasonic cleaning step). The scrub cleaning by the brush cleaning mechanism 20 is performed simultaneously with or before or after the ultrasonic cleaning step. The rotation speed of the spin chuck 12 is from 10 rpm to 1000 rpm.
The degree is preferred.

Then, the rotation of the substrate W by the substrate rotating mechanism 10 is stopped, and the supply of the cleaning liquid from the ultrasonic cleaning mechanism 20 is stopped. Lastly, immediately after the supply of the cleaning liquid from the auxiliary liquid supply mechanism 40 is stopped, the ultrasonic cleaning mechanism 20 and the brush cleaning mechanism 30 move from the path A3 to the standby position via the path A2 and the path A1. The substrate W is unloaded from the substrate cleaning apparatus 1 by the hand H of the substrate transfer robot, and the cleaning processing for one substrate W in the substrate processing apparatus 1 is completed.
In the above operation, an operation flow is set in the control unit 50 in advance, and the operation is controlled according to the setting. Thereafter, the substrate is washed and dried by the next washing / drying device, and is finally finished, and is stored in a cassette capable of storing a plurality of substrates W.

Next, the ultrasonic cleaning head 21 of the ultrasonic cleaning mechanism 20, which is a feature of the present invention, will be described in detail with reference to the drawings. FIG. 2 shows an ultrasonic cleaning head 2
FIG. 3 is a sectional view schematically showing the configuration of FIG.
(A) is a cross-sectional view as viewed from the side of the device in the longitudinal direction, FIG.
(B) is a plan view thereof. The ultrasonic cleaning head 21
For example, Teflon 4 (registered trademark) (poly tetra
A hollow plate-shaped diaphragm having a hollow rectangular rod-shaped body portion 211 made of fluororesin such as fluoroethylene) and a vibration surface VF in a substrate facing surface WF corresponding to the bottom surface of the body portion 211. 212, a vibrator 213, which is attached to the upper surface of the vibration plate 212 and receives a pulse from the ultrasonic oscillator 214, and ultrasonically vibrates the vibration plate 212 in a plan view, and a flat plate-shaped vibrator 213 in the substrate facing surface WF. And the nozzles 220 and 230 inserted in both longitudinal sides of the main body 211. In the substrate facing surface WF, the main body 211 including the tip portions NS of the nozzles 220 and 230 and the vibration surface VF of the vibration plate 212 are formed substantially flush.

The vibrating plate 212 is formed in a rectangular plate shape having upper and lower surfaces formed as flat surfaces and both ends supported by the main body 211. The vibration plate 212 has a function of transmitting vibration by resonating with ultrasonic waves generated from the vibrator 213.
It is made of a material such as quartz, stainless steel, aluminum, SiC, and tartan.

The vibrator 213 has a piezoelectric element 250, a ground electrode 251 provided over substantially the entire lower surface of the piezoelectric element 250, and a plurality of divided electrodes 252 provided on the upper surface of the piezoelectric element 250. I have. This split electrode 25
When a drive signal is given to the piezoelectric element 2, ultrasonic vibration is generated in the piezoelectric element 250, and the ultrasonic vibration is transmitted to the cleaning liquid via the vibration plate 212. As the piezoelectric element 250, an ultrasonic vibration generating element that generates ultrasonic vibration based on another principle, such as a magnetostrictive element, can be used instead.

FIG. 4 is an exploded perspective view of the vibrator 213.
The ground electrode 251 covers the lower surface of the piezoelectric element 250, and both ends of the ground electrode 251 are turned over and contact the upper surface of the piezoelectric element 250. The plurality of divided electrodes 252 are provided on the upper surface of the piezoelectric element 250 so as to be separated from each other, and are each formed in a comb shape.
In the example of FIG. 4, two divided electrodes 252a and 252b face each other, slits P1 and P2 are formed at the same pitch, and electrode main portions 252c and 252d having the same width enter slits P1 and P2. Will be installed. The vibration plate 212 and the vibrator 213 are bonded with, for example, an adhesive.

The split electrode 252 from the ultrasonic oscillator 214
a, 252b when the AC drive signal is applied to the diaphragm 21
A traveling wave of ultrasonic vibration (flexure wave) is generated on the second vibration plane VF. That is, the divided electrodes 252a and 252b have
Two types of AC drive signals, which are sine waves having a 90 ° phase difference, are supplied. Each split electrode 252a, 2
The portion directly below 52b expands and contracts according to the drive signal given to each split electrode, and a traveling wave propagating to one side on the surface of diaphragm 212 is generated according to the expansion and contraction. That is, FIG.
In the example, when the phase of the AC drive signal is shifted from the split electrode 252a to the split electrode 252b, the first electrode main portion 252c of the split electrode 252b is shifted from the first electrode main portion 252c of the split electrode 252a located on the left side in the drawing. Then, a traveling wave is generated to the right in the figure.

The main body portion 211 is fixed to the lower surface of one end of the swing arm 22 by a bolt or the like on the upper surface of a square rod shape.
30 is a nozzle pipe 22 passing through the inside of the swing arm 22.
The cleaning liquid supply source 43 to which the auxiliary liquid pipe 42 of the above-described auxiliary liquid supply mechanism 40 is connected is connected via 1 and 231. In the middle of the nozzle pipes 221 and 231,
Valves 222 and 232 for starting / stopping the supply of the cleaning liquid from the nozzles 220 and 230 are provided.

The nozzles 220 and 230 are arranged with the nozzle 220 on the downstream side and the nozzle 230 on the upstream side with respect to the rotation direction F which is the moving direction of the substrate W with respect to the ultrasonic cleaning head 21 with the diaphragm 212 interposed therebetween. Nozzle 220 (in addition,
The description is omitted because the configuration of the nozzle 230 is the same)
A side plate 223 erected on a side of the main body 211 that supports the diaphragm 212 on the peripheral surface in a direction perpendicular to the moving direction F of the substrate W.
(233) is formed by cutting. The tip portion NS of the main body 211, which is the substrate facing surface WF, has a discharge hole 22 for the cleaning liquid.
4 (234) is formed in a slit shape, and is formed longer than the vibration surface VF of the vibration plate 212 as shown in FIG.

The discharge hole 224 (234) is connected to the liquid reservoir 226 (236) via the liquid guide 225 (235).
It will be installed continuously. The discharge hole 224 (234) is formed to have a smaller sectional area than the sectional area of the liquid reservoir 226 (236). The connecting portions 221a and 221b (231a and 231b) shown in FIG. 3A where the nozzle pipe 221 (231) is branched are connected to the upper part of the liquid reservoir 226 (236) as appropriate.

Next, the first interval D1 may be an interval at which the gap space K is sufficiently filled with the cleaning liquid, and is usually 3 mm.
Hereinafter, it is preferably set to about 1 to 2 mm. In addition,
In this embodiment, the setting of the substrate facing distance is performed by the elevation drive source 25, and the above-described FIG.
As described in the above description, the substrate opposing interval K is set to two intervals of the first interval D1 and the second interval D2 by the lifting drive source 25.

Further, the ultrasonic cleaning head 21 having the above configuration
Is the center O of the substrate W, as shown in FIG.
Is located at one end (the left side in the figure) of the vibration surface VF, and the end Wc of the substrate W faces the other end (the right side in the figure). That is,
The vibration surface VF is set so as to cover a range slightly larger than the radius of the substrate W.

With the above configuration, the valves 222, 232
Are opened by the signal of the control unit 50 and the nozzles 220 and 2 are opened.
When the cleaning liquid is supplied from the substrate 30 and the ultrasonic cleaning head 21 is brought close to the position where the substrate facing distance D becomes the first distance D1, the space (the gap) sandwiched between the substrate W and the substrate facing surface WF. The space K) is filled with the cleaning liquid. And
For the cleaning liquid filled in the gap space K, the diaphragm 2
Ultrasonic vibration from 12 is applied, and ultrasonic cleaning of the substrate upper surface Wa is performed. Here, the ultrasonic oscillators 214 to 4
Power having a frequency of 00 KHz to 1 MHz is output.

At that time, first, in the nozzles 220 and 230, the cleaning liquid supplied from the nozzle pipes 221 and 231 is changed in the cross-sectional areas of the liquid guides 225 and 235 and the liquid reservoirs 226 and 236, so that the longitudinal directions of the liquid reservoirs 226 and 236 are changed. Charge in the direction.
Then, the cleaning liquid flows down the liquid guide portions 225 and 235, so that there is little deviation and the discharge holes 224 and 234 have a slit shape.
From the substrate upper surface Wa.

Next, the behavior of the cleaning liquid on the upper surface Wa of the substrate will be described. The distance between the portion where the substrate W and the substrate facing surface Wa are closest (hereinafter referred to as the closest distance) is 3 m.
m or less. Here, the ordinary cleaning liquid used for cleaning the upper surface Wa of the substrate forms a liquid film having a thickness of about 3 mm or more on the surface of the substrate due to its surface tension. Therefore, in a portion of the gap space K where the substrate facing interval is 3 mm or less, the gap space K is reliably filled with the cleaning liquid. Therefore, the ultrasonic vibration energy transmitted to the cleaning liquid can be sufficiently maintained, and the cleaning power of the substrate surface can be further improved. However, due to the rotation of the substrate W, a centrifugal force is applied to the cleaning liquid on the substrate upper surface Wa in a direction away from the rotation axis R, and a rotational force is applied to the cleaning liquid in the rotational direction F of the substrate W. Therefore, the cleaning liquid supplied to the substrate upper surface Wa tends to flow in the direction away from the rotation axis R and in the direction of the rotation direction F.

Here, the substrate W to which the cleaning liquid is supplied is on the other hand.
When the cleaning is performed only from the downstream side in the rotation direction (moving direction) F, the cleaning liquid is not filled even if the gap space K has a surface tension. Further, even if the rotation is performed only from the upstream side, if the rotation speed is too high, the diaphragm 212
The cleaning liquid is not interposed in the gap space K on the downstream side of the vibration surface VF. However, in this embodiment, the upstream side and the downstream side of the vibration surface VF of the vibration plate 212 in the rotation direction F (movement direction) of the substrate W are surrounded by the tip portions NS, NS of the nozzles 220, 230, Also, the nozzle 220,
Since the vibrating surface VF is provided in the area of the opening length of the discharge holes 224 and 234 of the 230, the gap space K can always intervene over the entire surface of the vibrating surface VF. That is, the cleaning liquid is supplied from substantially the periphery of the vibration surface VF, and the cleaning liquid is always interposed in the gap space K by the surface tension, so that the ultrasonic vibration can be sufficiently applied to the cleaning liquid.

Further, when the relationship between the supply flow rate of the cleaning liquid and the rotation speed of the substrate W is appropriate, for example, if the substrate facing surface WF of the ultrasonic cleaning head 21 has structural irregularities, the cleaning liquid is not filled and air intervenes. However, in this embodiment, the substrate facing surface WF
Are formed substantially flush with each other, so that the air in the gap space K is expelled and filled with the cleaning solution together with the supply of the cleaning solution in the gap space K. Therefore, it is possible to prevent the diaphragm 212 from being damaged.

Further, the cleaning liquid filled in the gap space K does not come into contact with the atmosphere in the region inside the gap space K, so that air such as air bubbles does not enter. Therefore, when the ultrasonic vibration is applied to the cleaning liquid, the ultrasonic vibration energy is transmitted efficiently, so that fine particles on the substrate surface can be sufficiently removed, and the cleaning power on the substrate surface can be improved.

When an AC drive signal is supplied to the divided electrodes 252a and 252b in this state, a traveling wave is generated from the center O of the substrate W toward the end Wc on the vibration surface VF of the vibration plate 212. The cleaning liquid is vibrated by the traveling wave, and is moved to the outside of the substrate W while rotating in the rotation direction F. In other words, the cleaning liquid is finally moved by the traveling wave to the end W of the substrate W.
c to the outside. Therefore, the substrate surface Wa is uniformly cleaned over the entire vibration surface VF,
The cleaning liquid in the gap space K flows out of the gap space K smoothly without staying in the gap space K. At this time, since the traveling wave is generated from the center O of the substrate toward the end Wc, re-contamination of the upper surface Wa of the substrate can be reliably prevented.
Therefore, the efficiency of replacement of the cleaning liquid in the gap space K is improved, and the cleaning liquid to which fresh ultrasonic vibration is applied is always in contact with the substrate surface, so that the cleaning power of the substrate surface can be further improved. In addition, since the traveling wave of the ultrasonic vibration is generated along with the normal vibration of the fluid on the vibration surface, the cleaning power of the surface of the substrate can be improved.

In the first embodiment, the AC drive signal having the same waveform is applied to the divided electrodes 252a and 252b. However, the AC drive signal is obtained by superimposing a relatively low frequency component and a relatively high frequency component. A drive signal having characteristics may be used.

<Second Embodiment> In the above embodiment, the traveling wave for the cleaning liquid is formed by dividing the electrodes, but the ultrasonic cleaning head 3 having the structure shown in FIG.
00 may be set. FIG. 5 shows this ultrasonic cleaning head 30.
0A is a plan view showing the relationship between the substrate W and the substrate facing surface WF, the vibration surface VF, and the tip end portion NS of the nozzle, and FIG. 6A is a side view as viewed from the longitudinal direction, and FIG. It is the top view seen from the lower surface. In addition, in the configuration of FIGS. 5 and 6, the same portions as the configurations of FIGS.
The detailed description is omitted, and the same reference numerals as those in FIGS.

In the ultrasonic cleaning head 300,
The configuration of the vibrator 302 with respect to the diaphragm 301 is mainly different. As shown in FIG. 6, this ultrasonic cleaning head 300
Has two vibrators 303 and 304 at the left and right ends of the vibrating plate 301 as the vibrator 302 in the longitudinal direction.
One vibrator 303 includes a piezoelectric element 305 and a piezoelectric element 3
05 so as to cover the lower surface of the piezoelectric element 30.
5, a ground electrode 306 extending on the upper surface of the piezoelectric element 30
(5) an electrode 307 which is provided on an open surface of the upper surface,
It is composed with. The other vibrator 304 has a similar configuration.

When a traveling wave is generated by the structure of the second embodiment as in the first embodiment, a vibrator 303 close to the center O of the substrate W is used as a vibrator and By using the vibrator 304 on the end Wc side of W as a vibration absorber, the end W
A traveling wave traveling toward c can be generated. The cleaning liquid is in contact with the vibration surface VF, and the traveling wave excited by the ultrasonic vibration is traveling rightward in FIG. 6 on the vibration surface VF. The principle of driving an object such as a cleaning liquid by such a traveling wave is used in an ultrasonic motor, and in the above embodiment, the cleaning liquid is driven by the traveling wave on the substrate surface Wa.

Then, the vibrator 303 is vibrated, a load having an appropriate impedance is connected to the vibrator 304, and the traveling wave is absorbed by generating electric power by the vibration of the traveling wave. That is, as shown in FIG. 6A, an ultrasonic oscillator 214 is connected to the vibrator 303, and a circuit 308 including a load resistor 309 and a coil 310 is connected to the vibrator 304. Instead of using the vibrator 304 as a vibration absorber, the traveling wave may be absorbed by a mechanical method, for example, by replacing the vibrator 304 with an ultrasonic absorber.

According to the above configuration, it is possible to generate a traveling wave traveling substantially in one direction from the vibrator to the vibration absorber side on the upper surface Wa of the substrate. Therefore, the substrate upper surface Wa is uniformly cleaned over the entire vibration surface VF, and the gap space K
The cleaning liquid inside smoothly flows out of the gap space K without staying in the inside. Therefore, the cleaning power of the surface of the substrate can be improved.

As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and can be embodied in other forms. For example, in the above-described embodiment, the substrate facing distance D is set to the first distance D1 by the lifting / lowering drive source 25 as the distance setting means.
The substrate facing distance D (D1) may be finely adjusted by a distance setting means different from 5. That is,
The vertical distance D is set to the first distance D by the elevation drive source 25.
The distance D may be roughly set in the vicinity of 1, and the distance D between the substrates may be precisely set to the first distance D1 by another distance setting means.

Further, in one embodiment described above,
During the cleaning process of the substrate W, the ultrasonic cleaning head 21 is fixedly arranged on the substrate upper surface Wa by the oscillation driving source 24 and the oscillation transmitting mechanism 24t, but the ultrasonic cleaning head 21 is moved along the substrate upper surface Wa. May be moved linearly. For example, instead of the swing transmission mechanism 24t, a ball screw mechanism or the like described as the lifting transmission mechanism 25t is used, and ultrasonic cleaning is performed in a direction away from and near the rotation axis R of the substrate W along the substrate upper surface Wa. The head 21 may be reciprocated linearly (oscillated).

Further, in the above-described embodiment,
Although one ultrasonic cleaning head is disposed in the radial direction from the center O of the substrate W, two ultrasonic cleaning heads may be disposed symmetrically with the center O of the substrate W as a base point.
By doing so, each ultrasonic cleaning head may generate a traveling wave from the center O of the substrate W toward the end Wc to move the cleaning liquid.

Further, in the above-described embodiment, the tip portion NS of the nozzle provided in the ultrasonic cleaning head 21 has a slit shape elongated in a predetermined direction, but may have any shape. For example, a plurality of short slit-shaped openings may be used.

Furthermore, in the above-described first embodiment, the substrate facing surface WF is a plane that faces substantially parallel to the substrate upper surface Wa, but is not limited thereto, and faces the substrate upper surface Wa at an angle. It may be a flat surface or the substrate upper surface W
The curved surface may be protruded or depressed with respect to a.

In the above-described embodiment, pure water is used as the cleaning liquid. However, any liquid can be used as long as it can clean the substrate, such as hydrofluoric acid, sulfuric acid, hydrochloric acid, or the like.
It may be a chemical such as nitric acid, phosphoric acid, acetic acid, ammonia or an aqueous solution of hydrogen peroxide thereof.

In the above-described embodiment, the material of the main body 211 of the ultrasonic cleaning head 21 and the like is made of a fluororesin. However, the material may be a liquid having resistance to the cleaning liquid and sufficient mechanical strength. Anything is fine. For example,
When the cleaning liquid is pure water, a material such as a resin such as vinyl chloride or acrylic, or a metal such as stainless steel or aluminum may be used. When the cleaning liquid is a chemical, a resin such as a fluororesin or vinyl chloride is mainly used, although it depends on the type of the chemical.

In the above-described embodiment, the substrate rotating mechanism 10 rotates the substrate W while holding it by the spin chuck 12 that sucks and holds the lower surface Wb of the substrate. A pin holding type spin chuck that rotates around the rotation axis R of the substrate W while holding the pins below and at the end face may be used.

Alternatively, the substrate rotation mechanism 10 may be at least three roller pins that rotate around an axis parallel to the rotation axis R of the substrate W while abutting on the end surface of the peripheral portion of the substrate W. . The substrate rotating mechanism 10 using the roller pins is particularly effective when ultrasonic cleaning is performed on both surfaces of the substrate W. If the ultrasonic cleaning head 21 is arranged at a position sandwiching the substrate W, the substrate rotation mechanism 10 can be used for both surfaces (Wa and Wb). Ultrasonic cleaning can be performed well over the entire area of (1). In this case, the substrate lower surface W
The ultrasonic cleaning head 21 for cleaning b has its substrate facing surface WF facing upward. In such a case, by using the ultrasonic cleaning head 21 according to the first embodiment,
The cleaning liquid is temporarily held by a predetermined amount. For this reason, the gap K can be easily filled with the cleaning liquid, and sufficient ultrasonic vibration can be applied to the cleaning liquid.

In the above-described embodiment, C
Although the case of cleaning the substrate W after the MP processing has been described, the present invention is not limited to this, and the present invention is widely used.
The present invention can also be applied to a device for cleaning the substrate W.

Further, in one embodiment described above,
Although the case where a semiconductor wafer is cleaned as the substrate W has been described, the present invention relates to a glass substrate for a liquid crystal display device,
The present invention can be widely applied to cleaning of a DP (plasma display panel) substrate, or other various substrates such as a glass substrate or a ceramic substrate for a magnetic disk. Further, as for the shape of the substrate, the present invention can be applied not only to the circular substrate of the above-described embodiment but also to a square or rectangular square substrate.

In addition, various design changes can be made within the scope of the matters described in the claims.

[0080]

As described above, according to the present invention,
When the fluid is filled in the gap space, ultrasonic vibration is applied and the ultrasonic vibration energy is transmitted efficiently, so that fine particles on the substrate surface can be sufficiently removed, and the cleaning power of the substrate surface can be improved. This has the effect.
At that time, a traveling wave can be generated and moved in the fluid, and fine particles on the substrate surface can be efficiently and sufficiently removed by the traveling traveling wave, so that the detergency of the substrate surface can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a configuration of a main part of a substrate cleaning apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the relationship between the substrate facing surface, the vibration surface, the tip of the nozzle, and the substrate of the ultrasonic cleaning head of the substrate cleaning apparatus according to one embodiment of the present invention, as viewed from the side of the apparatus. is there.

3A and 3B are diagrams schematically illustrating a configuration of an ultrasonic cleaning head according to an embodiment of the present invention, where FIG. 3A is a cross-sectional view as viewed from a longitudinal side, and FIG. FIG.

FIG. 4 is an exploded perspective view of a vibrator according to one embodiment of the present invention.

FIG. 5 shows a substrate facing surface, an oscillating surface, and a tip of a nozzle of an ultrasonic cleaning head according to another embodiment of the present invention;
It is sectional drawing seen from the apparatus side which shows the relationship with a board | substrate.

6A and 6B are diagrams schematically illustrating a configuration of an ultrasonic cleaning head according to another embodiment of the present invention. FIG. 6A is a cross-sectional view as viewed from the side in the longitudinal direction, and FIG. It is the top view seen from.

FIG. 7 is an explanatory view of a conventional cleaning device.

[Explanation of symbols]

 Reference Signs List 10 substrate rotation mechanism (substrate rotation means) 11 spin axis 12 spin chuck 20, 110 ultrasonic cleaning mechanism 21, 300 ultrasonic cleaning head (ultrasonic cleaning means) 211 main body 212, 301 diaphragm 213, 302, 303, 304 Vibrator 250, 305 Piezoelectric element 251, 306 Ground electrode 252, 252a, 252b Split electrode 307 Electrode 214 Ultrasonic oscillator 30 Brush cleaning mechanism 40 Auxiliary liquid supply mechanism 41 Auxiliary liquid supply nozzle 42 Auxiliary liquid pipe 43 Cleaning liquid supply source 44 Valve A1 , A2, A3 Path of the substrate facing surface D Substrate facing distance D1 First distance D2 Second distance F Rotation direction (moving direction) K Gap space 220, 230 Nozzle NS Tip of nozzle O Center of substrate R Rotation of substrate Axis VF Vibration surface W Substrate Wa Substrate upper surface Wb Substrate lower surface Wc Substrate Edge WF Substrate facing surface

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) H01L 21/304 643 H01L 21/304 643A 643D F-term (Reference) 3B116 AA03 AB23 AB34 AB47 BA02 BA13 BB22 BB84 BB85 CC01 CC03 3B201 AA03 AB23 AB34 AB47 BA02 BA13 BB22 BB84 BB85 BB92 BB93 BB96 CC01 CC11

Claims (6)

[Claims] 1. An ultrasonic cleaning means having a vibrating surface disposed opposite to a relatively moving substrate at an interval, an oscillator for generating ultrasonic vibration on the vibrating surface, and a vibrating surface of the ultrasonic cleaning means And a fluid supply unit for supplying a fluid used for processing the substrate, at an interval between the substrate and the substrate, wherein the ultrasonic cleaning unit is arranged in parallel with the vibration surface with a plurality of divided electrodes each receiving a different AC drive signal. A substrate cleaning apparatus, comprising: 2. The substrate cleaning apparatus according to claim 1, wherein the plurality of divided electrodes are arranged in parallel in a longitudinal direction of a vibration surface. 3. The substrate cleaning apparatus according to claim 1, further comprising: a substrate rotating unit configured to rotate the substrate in a predetermined rotation direction about a vertical rotation axis. A substrate cleaning apparatus, characterized in that an alternating-current drive signal having a phase shifted is applied in order from a divided electrode closer to a rotation axis of a substrate among the divided electrodes. 4. An ultrasonic cleaning means having a vibrating surface opposed to a relatively moving substrate at an interval, a vibrator for generating ultrasonic vibration on said vibrating surface, and a vibrating surface of said ultrasonic cleaning means. A fluid supply unit for supplying a fluid used for processing the substrate at an interval between the substrate and the substrate, wherein the ultrasonic cleaning unit has the vibrator at one end of the vibrating surface. Substrate cleaning equipment. 5. The substrate cleaning apparatus according to claim 4, wherein the ultrasonic cleaning unit arranges the vibrator at one end in a longitudinal direction of the vibrating surface. 6. The substrate cleaning apparatus according to claim 4, further comprising: a substrate rotating unit configured to rotate the substrate in a predetermined rotation direction about a vertical rotation axis. The substrate cleaning apparatus, wherein the cleaning unit is arranged on the vibrator on a side of the vibrating surface close to a rotation axis of the substrate.