JPH09223682A - Cleaning apparatus and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate setting of contact pressure and keep the contact pressure unchanged by detecting a current flowing through a driving source and changed in response to a contact state between a cleaning member and an article to be cleaned, and controlling the contact state between the cleaning member and the article to be cleaned in response to a detection signal. SOLUTION: A driving shaft 42 is rotated with a vertical driving motor 41, and a cleaning brush 31 is vertically driven through a cleaning brush 31, a supporter 37, a rocking shaft 36, and a horizontal arm 33. A rotating motor 34 is connected with a controller 52 through an ammeter 51 as a detector for rotating the cleaning brush 31. The controller 52 supplies power to the rotating motor 34, and detects a current flowing through the rotating motor 34 detected by the ammeter 51. A driving signal D is outputted to a vertical driving motor 41 for vertically driving the cleaning brush 31 in response to a comparison of a current I as a detection signal detected by the controller 52 and a set value S previously set by the controller 62.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning apparatus and method for cleaning an object to be cleaned such as a semiconductor wafer or a liquid crystal glass substrate with a cleaning brush.

[0002]

2. Description of the Related Art In the manufacturing process of semiconductor devices, liquid crystal display devices, etc., there is a lithographic process for forming a circuit pattern on a semiconductor wafer or glass substrate as an object to be cleaned. In the lithography process, as is well known, a resist is applied to the semiconductor wafer, and the resist is irradiated with light through a mask on which a circuit pattern is formed, and then a portion of the resist which is not irradiated (or irradiated with light). The circuit pattern is formed by repeating a series of steps of removing the removed portion) and treating the removed portion several tens of times.

In each process, if the semiconductor wafer is contaminated, the circuit pattern cannot be precisely formed, which causes defective products. Therefore, when forming a circuit pattern in each step, the semiconductor wafer is washed in a clean state in which fine particles such as resist and dust do not remain.

[0004] As the apparatus for cleaning the object to be cleaned, there are a batch type in which a plurality of semiconductor wafers are immersed in a cleaning tank containing a cleaning liquid for cleaning, and a method for rotating one object to be cleaned, and There is a single-wafer type in which a cleaning liquid is sprayed on an object to perform cleaning, and a single-wafer type having a high cleaning effect tends to be used as an object to be cleaned becomes larger.

The single-wafer cleaning apparatus includes a spin cleaning apparatus for rotating and cleaning an object to be cleaned. In this cleaning apparatus, in order to further enhance the cleaning effect, the object to be rotated is rotated. A cleaning brush, which is also driven to rotate, is brought into contact with the upper surface of the object to be cleaned, and a cleaning liquid is supplied to the contact portion to clean the object to be cleaned.

The effect of cleaning the object to be cleaned in the above-mentioned spin type cleaning apparatus is greatly influenced by the contact pressure of the cleaning brush on the object to be cleaned. That is, if the contact pressure of the cleaning brush with respect to the object to be cleaned is weak, the cleaning effect becomes low, and if it is too high, the cleaning brush may damage the object to be cleaned. Therefore, in order to obtain a reliable cleaning effect, it is necessary to set the contact pressure of the cleaning brush on the object to be cleaned to a predetermined state.

Conventionally, the contact pressure of the cleaning brush against the object to be cleaned drives the cleaning brush in the direction of contacting the object to be cleaned, and the cleaning brush contacts the object to be cleaned and the object to be cleaned vibrates. The start position is recognized as the zero point, or the pressure sensor is attached to the object to be cleaned, and the position where the pressure detected by the pressure sensor fluctuates due to contact with the cleaning brush is recognized as the zero point. Then, the cleaning brush is pressed against the object to be cleaned by a predetermined amount from the zero point, so that a constant contact pressure is applied to the object to be cleaned.

However, according to such a method,
In the former case, not only does it require skill to detect the zero point, but there may be a difference depending on the measurer.In the latter case, the sensor is attached to the object to be cleaned in order to recognize the zero point. Since it had to be done, there were times when it took time and effort to do that work.

What is common to both of them is that it is not easy to set a predetermined contact pressure after detecting the zero point, and the brush bristles of the cleaning brush in particular wear with use. Even if the contact pressure of the cleaning brush is set based on the zero point detected in advance, the contact pressure may not be maintained constant due to abrasion of the brush bristles.

[0010]

As described above, conventionally, in setting the contact pressure between the cleaning brush and the object to be cleaned, it depends on the skill of the operator or a pressure sensor is provided on the object to be cleaned. Detects the zero point where the cleaning brush contacts the object to be cleaned,
Then, the worker brought the cleaning brush into contact with the object to be cleaned at a predetermined pressure based on the zero point.

Therefore, not only is it necessary to detect the zero point, it takes a lot of skill to bring the cleaning brush into contact with the object to be cleaned at a predetermined pressure, and it is troublesome. Even if the contact pressure is set, the contact pressure may not be kept constant due to abrasion of the bristles.

The present invention has been made in view of the above circumstances, and an object thereof is to easily and surely detect the zero point and set the contact pressure between the cleaning member and the object to be cleaned, and It is an object of the present invention to provide a cleaning apparatus and a method thereof, which can maintain a constant contact pressure even when the bristles of the brush are worn.

[0013]

According to a first aspect of the present invention, in a cleaning apparatus for cleaning an object to be cleaned by a cleaning member that is rotationally driven, a drive source that rotationally drives the cleaning member, the cleaning member and the object to be cleaned. Driving means for driving the cleaning object in a direction relatively approaching and separating, detection means for detecting a current value flowing in the driving source which changes according to a contact state between the cleaning member and the cleaning object, and this detection The control means drives the driving means according to a detection signal of the means to control the contact state between the cleaning member and the object to be cleaned.

According to a second aspect of the present invention, there is provided a cleaning method for cleaning an object to be cleaned using a cleaning member rotationally driven by a driving source, wherein the cleaning member and the object to be cleaned are not in contact with each other. A first step of measuring a current value flowing through the drive source when the cleaning member is rotated; and a first step of measuring a current value flowing through the drive source when the cleaning member comes into contact with the object to be cleaned. It is characterized by including the step 2 and the third step of setting the contact pressure between the cleaning member and the object to be cleaned based on the current value measured in the second step.

According to the first and second aspects of the present invention, when the cleaning member and the object to be cleaned come into contact with each other, the value of the current flowing through the drive source for rotationally driving the cleaning member changes. To be detected. Then, by setting the contact pressure between the cleaning member and the object to be cleaned based on the value of the current flowing in the drive source, the contact pressure can be set to a predetermined value, and the brush bristles can be used with use. Even if the wear occurs, a constant contact pressure can be maintained by setting the current value flowing in the drive source to a predetermined value.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. The cleaning processing apparatus of the embodiment of the present invention shown in FIG. 1 includes a processing container 1. The processing container 1 is composed of a bottomed main body 1a having an open upper surface and a conical cylindrical cover 1b slidably provided with respect to the main body 1a and having a peripheral wall inclined. It can be slid up and down by a drive mechanism (not shown).

At the bottom of the main body 1a of the processing container 1, one end of a plurality of discharge pipes 2 is connected to the peripheral portion, and an insertion hole 4 surrounded by a flange 3 is formed at the center. The support shaft 5 is inserted through the insertion hole 4. An upper portion of the support shaft 5 projects into the processing container 1, and a lower end portion thereof is fixed to a base plate 6 arranged below the processing container 1. The discharge pipe 2 communicates with a waste liquid tank (not shown).

A rotary chuck 11 constituting a holding mechanism is rotatably supported on the support shaft 5. The rotary chuck 11 has a disk-shaped base with a through hole 12a formed in the center thereof.
It has a space 12. A cylindrical support portion 13 is vertically provided on the lower surface of the base 12, that is, at a position corresponding to the through hole 12a. The support portion 13 is externally fitted to the support shaft 5, and upper and lower portions of the support shaft 5 are rotatably supported by bearings 14, respectively.

A driven pulley 15 is provided on the outer peripheral surface of the lower end portion of the support portion 13. The base plate 6 has a metal
A motor 16 is provided, and a driving pulley 17 is fitted on a rotating shaft 16a of the motor 16. This drive pulley 17
A belt 18 is stretched between the driven pulley 15 and the driven pulley 15. Therefore, when the motor 16 operates, the support portion 13, that is, the rotary chuck 11 is rotationally driven.

On the upper surface of the base 12 of the rotary chuck 11, four columns 19 are erected in the circumferential direction. A support pin 21 a is provided at the upper end of each column 19 and the support pin 21 a
An engaging pin 21b, which is outside of a and is taller than the support pin 21a, is provided so as to project.

On the upper end of the column 19, a semiconductor wafer 22 as an object to be cleaned is supported by a support pin 21a on the lower surface of the peripheral portion and is detachably held by engaging the outer peripheral surface with the engaging pin 21b. It Therefore, the semiconductor wafer 2
2 is rotated integrally with the rotary chuck 11.

The support shaft 5 is provided at its upper end with a conical head portion 5a having a diameter larger than that of the support shaft 5. A gas supply passage 30 for an inert gas such as N ₂ having a tip opened on the upper surface of the head 5a is provided on the support shaft 5, and a tip is also provided on the upper surface of the head 5a through a nozzle hole 32a. The cleaning liquid supply passage 30a for the cleaning liquid is formed along the axial direction. The gas supply passage 30a communicates with a gas supply source (not shown), and the cleaning liquid supply passage also communicates with a cleaning liquid supply source (not shown).

The inert gas supplied to the gas supply passage 30 is jetted toward the semiconductor wafer 22 held on the support column 19, and the cleaning liquid L supplied to the cleaning liquid supply passage 30a has the nozzle hole at the tip thereof. It is adapted to be ejected from the surface 32a toward the lower surface of the semiconductor wafer 22.

On the upper surface side of the semiconductor wafer 22 held by the rotary chuck 11, a circular cleaning brush 3 as a cleaning member for cleaning the upper surface of the semiconductor wafer 22.
1 is arranged. The cleaning brush 31 has a swing mechanism 3
2 allows the semiconductor wafer 22 to be swung in the radial direction.

That is, the swinging mechanism 32 has a hollow cylindrical horizontal arm 33. A rotary motor 34 as a drive source is built in the tip of the horizontal arm 33 with the rotary shaft 34a being vertical, and the cleaning brush 31 is attached to the rotary shaft 34a.

Further, a nozzle tube 35 as a supply means connected to a supply source of the cleaning liquid (not shown) is inserted through the horizontal arm 33. The tip of the nozzle tube 35 is led out downward from the tip of the horizontal arm 33, and its tip opening is directed to the outer peripheral surface of the cleaning brush 31. Therefore, the cleaning liquid L is supplied from the radial outside of the cleaning brush 31 by the nozzle pipe 35.

In this embodiment, as shown in FIG. 2, the supply direction A of the cleaning liquid L supplied from the nozzle pipe 35 toward the cleaning brush 31 is substantially tangential to the cleaning brush 31, and It is set in a direction along the rotation direction B of the cleaning brush 31. Cleaning brush 3
The rotation direction of 1 may be the same direction or the opposite direction to the rotation direction of the semiconductor wafer 22.

The base end of the horizontal arm 33 is connected to the upper end of a swing shaft 36 whose axis is vertical. The lower end of the swing shaft 36 is projected below the base plate 6 and is swingably supported by a support body 37.

A pair of guides 38 are provided on one side surface of the support 37 along the vertical direction, and the guides 38 are vertically arranged on one side surface of a mounting plate 39 which is vertically provided on the lower surface of the base plate 6. It is slidably engaged with a rail 40 provided along the direction.

A vertical drive motor 41 is provided at a portion of the mounting plate 39 below the support 37. The vertical drive motor 41 includes a drive shaft 42 such as a screw shaft.
The drive shaft 42 is screwed to the support 37.

Therefore, when the drive shaft 42 is rotationally driven by the vertical drive motor 41, the support 3
7 is driven up and down along the rail 39. That is, the cleaning brush 31 is vertically driven via the support 37, the swing shaft 36, and the horizontal arm 33.

A swing drive source 43 is provided on the other side of the support 37.
Is attached. The swing drive source 43 has a storage box 44 and a motor 45 provided on the lower surface of the storage box 44. A drive gear (not shown), which is rotationally driven by the motor 45, is accommodated in the storage box 44.

A driven gear (not shown) is provided at the lower end of the swing shaft 36 supported by the support 37.
A belt is stretched between the driven gear and the drive gear. Therefore, the swing shaft 36 is rotated by the operation of the motor 45 of the swing drive source 43.

As shown in FIG. 3, an engaging piece 46 is projectingly provided on a portion of the outer peripheral surface of the swing shaft 36 on the upper surface side of the support body 37. The engagement piece 46 is a first stopper 47 provided on the support body 37 according to the rotation direction of the swing shaft 36.
And the second stopper 48. That is, the swing shaft 3
6 is the motor 4 within the range of an angle .theta. At which the engagement piece 46 contacts the first stopper 47 and the second stopper 48.
It is adapted to be reciprocally rotated by 5.

When the swing arm 36 is reciprocally rotated within the range of the angle .theta. And the horizontal arm 33 is swung by the rotation, the cleaning brush 31 provided at the tip of the horizontal arm 33 is As shown by a solid line and a broken line in FIG. 2, the semiconductor wafer 22 held by the rotary chuck 11 is swung between a radial center portion and a peripheral portion. This swing range is indicated by arrow D in FIG.

The rotating motor 34 for rotating the cleaning brush 31 is connected to the controller 52 via an ammeter 51 as a detector. The control device 52 supplies electric power to the rotary motor 34, and at the same time, the current value flowing through the rotary motor 34 detected by the ammeter 51, that is, the rotary motor 34.
A current value that fluctuates according to the load applied to the controller 34 is detected.

The current value I as a detection signal detected by the control device 52 is compared with a preset value S set by the control device 52, and the cleaning brush 31 is vertically driven according to the comparison. The drive signal D is output to the motor 41.

FIG. 4 shows the current value I detected by the ammeter 51.
Shows the change in In this figure, the vertical axis indicates the ammeter 51.
Of the cleaning brush 31 against the semiconductor wafer 22 is plotted along the horizontal axis.

The range indicated by 0 to A on the horizontal axis of the figure is when the load where the cleaning brush 31 is not in contact with the semiconductor wafer 22 is 0, and in this range, the rotary motor 34 has X on the vertical axis.
A constant current flows as shown by. When the cleaning brush 31 is lowered and brought into contact with the semiconductor wafer 22, the rotation mode is changed.
Since the load applied to the motor 34 increases, the value of the current flowing through the rotary motor 34 increases as the load increases.

Therefore, the controller 52 recognizes the point A, which is the position where the value of the current flowing through the rotary motor 34 starts to increase from X, as the zero point at which the cleaning brush 31 contacts the semiconductor wafer 22. Then, the cleaning brush 31 is lowered to the position of the pressing amount B where the current value becomes Y from the zero-point current value X, that is, the position where the cleaning brush 31 has a contact pressure suitable for cleaning the semiconductor wafer 22. The drive signal D is output to the vertical drive motor 41.

Next, a case where the semiconductor wafer 22 is cleaned by the spin cleaning apparatus having the above structure will be described. First, after holding the semiconductor wafer 22 on the rotary chuck 11 with the cleaning brush 31 retracted upward, the motor 16 is operated to rotate the semiconductor wafer 22 together with the rotary chuck 11.

Then, the rotating motor 34 is operated to rotate the cleaning brush 31, and the cleaning liquid L is supplied from the cleaning liquid supply passage 32 of the support shaft 5 and the nozzle pipe 35 to the lower surface and the upper surface of the semiconductor wafer 22. Meanwhile, the vertical drive motor 41 is operated to lower the cleaning brush 31. Also,
The oscillating drive source 43 is operated to oscillate the horizontal arm 33, that is, the cleaning brush 31 on the upper surface of the semiconductor wafer 22 within the range of the angle θ as shown by an arrow D in FIG.

The cleaning brush 31 is a vertical drive motor 41.
When the semiconductor wafer 22 is contacted with the semiconductor wafer 22 by lowering to the zero point indicated by point A in FIG.
Since the controller 52 starts to rise from the cleaning brush 31.
Touches the semiconductor wafer 22, that is, the zero point A is recognized.

Based on the recognition of the zero point A described above, the controller 52 drives the vertical drive motor 41 from the zero point A to a position where the cleaning brush 31 has a predetermined contact pressure with the semiconductor wafer 22. The signal D is output. That is, the cleaning brush 31 is lowered from the zero point A to the position B where the current value flowing through the ammeter 51 is Y. As a result, the cleaning brush 31 applies a contact pressure suitable for cleaning the semiconductor wafer 22, and the upper surface of the semiconductor wafer 22 is brushed by the cleaning brush 31 without being scratched. The fine particles that have been formed will be removed.

The brush bristles of the cleaning brush 31 are worn as they are used. However, the cleaning brush 31
The pressing amount of the cleaning brush 31 against the semiconductor wafer 22 is the zero point A at which the cleaning brush 31 contacts the semiconductor wafer 22,
Since the current value detected by the ammeter 51 from the zero point A is set to Y, the contact pressure of the cleaning brush 31 with respect to the semiconductor wafer 22 is not affected by the abrasion of the brush bristles.
It will be set to a fixed value.

Therefore, the cleaning of the semiconductor wafer 22 by the cleaning brush 31 can be surely performed by a constant contact pressure even if the bristles of the semiconductor wafer 22 are worn due to use.

The present invention is not limited to the above embodiment. For example, the cleaning member is not limited to the cleaning brush, and may be a material that can remove fine particles adhering to the semiconductor wafer without damaging it, for example, a soft elastic material such as a sponge formed into a disc shape or a ring shape. Of course, in the above-described embodiment, the configuration in which the cleaning brush is driven up and down has been described, but the present invention is also applied to a configuration in which the cleaning brush is held at a fixed position and an object to be cleaned is driven up and down. be able to.

Further, the cleaning member is configured to be rotationally driven with its axis line perpendicular to the plate surface of the object to be cleaned, but the cleaning member has its axis line parallel to the plate surface of the object to be cleaned. The present invention can be applied to the case of being rotationally driven. further,
The object to be cleaned is not limited to a semiconductor wafer, and may be a liquid crystal glass substrate or the like. The point is that the present invention is effective for those requiring precise cleaning.

[0049]

As described above, according to the first and second aspects of the present invention, the drive source for rotationally driving the cleaning brush changes according to the contact state between the cleaning brush and the object to be cleaned. The flowing current value is detected, and the contact state between the cleaning brush and the object to be cleaned is controlled according to the detection signal.

Therefore, it is easy to set the state in which the cleaning brush and the object to be cleaned come into contact with each other at a predetermined contact pressure based on the recognition of the zero point where the cleaning brush comes into contact with the object to be cleaned and the recognition of the zero point. Moreover, it can be surely performed. Moreover, even if the brush bristles of the cleaning brush are worn out due to use, the contact state is set based on the load applied to the drive source that rotationally drives the cleaning brush, and in that case also the cleaning effect is impaired and the cleaning target is cleaned. It is possible to set a contact state that does not damage the.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram for explaining the flow of the cleaning liquid on the upper surface of the semiconductor wafer.

FIG. 3 is a sectional view taken along the line AA of FIG. 1;

FIG. 4 is a graph for explaining the relationship between the current value flowing in the rotation motor and the pressing amount.

[Explanation of symbols]

 11 ... Rotating chuck, 31 ... Cleaning brush (cleaning member), 34 ... Rotating motor (driving source), 35 ... Nozzle tube (supplying means), 36 ... Oscillating shaft (oscillating mechanism), 41 ... Vertical driving motor -Ta (driving means), 51 ... ammeter (detecting means), 52 ... control device (control means).

Claims (2)

[Claims] 1. A cleaning device for cleaning an object to be cleaned by a cleaning member that is rotationally driven, wherein a drive source that rotationally drives the cleaning member and a direction in which the cleaning member and the object to be cleaned are relatively brought into contact with each other. Driving means, a detecting means for detecting a current value flowing in the driving source which changes according to a contact state between the cleaning member and the object to be cleaned, and the driving means according to a detection signal of the detecting means. A cleaning processing apparatus comprising: a control unit that is driven to control a contact state between the cleaning member and the object to be cleaned. 2. A cleaning processing method for cleaning an object to be cleaned using a cleaning member which is rotationally driven by a drive source, wherein the cleaning member is rotated in a state where the cleaning member and the object to be cleaned are not in contact with each other. A first step of measuring a current value flowing through the drive source, and a second step of measuring a current value flowing through the drive source when the cleaning member comes into contact with the object to be cleaned, A cleaning treatment method comprising: a third step of setting a contact pressure between the cleaning member and the object to be cleaned based on a current value measured in the second step.