JPH05200350A - Device for cleaning end of substrate - Google Patents

Abstract

PURPOSE:To satisfactorily clean off an unnecessary thin film on the peripheral end face of a rectangular substrate without adversely affecting the film formed on the substrate and without leaving a cleaning soln. CONSTITUTION:A rectangular substrate 1 with a thin film formed on the surface by spin coating is held by a substrate holding means capable of being rotated on its vertical axis, a cleaning soln. is discharged from a nozzle 3 over the rear of the substrate 1 to clean off the unnecessary thin film, a gas nozzle 24 is provided to supply a gas at the corner of the rear of the substrate 1 to blow off the remaining deposit, hence the rear of the substrate 1 is cleaned, and the remaining deposit at the corner of the rear is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass substrate for a liquid crystal or a glass for a photomask on which a thin film such as a photoresist coating solution, a photosensitive polyimide resin or a dyeing agent for a color filter is formed by spin coating. The present invention relates to a substrate edge cleaning apparatus that discharges a cleaning liquid onto a rectangular substrate such as a substrate on the back surface side of the rectangular substrate after the thin film is formed to clean and remove unnecessary thin films on the peripheral end surface of the rectangular substrate.

[0002]

2. Description of the Related Art A rectangular substrate having a thin film as described above is inserted into and removed from a cassette during various processing steps after the thin film is formed on the surface of the rectangular substrate in the manufacturing process or the like. Or it is held by the transport mechanism. At this time,
It is known that when the edge of the rectangular substrate comes into contact with the storage groove in the cassette or the chuck portion of the transport mechanism, the unnecessary thin film on the edge of the rectangular substrate peels off and becomes a dust source.

Further, if a part of the unnecessary thin film on the peripheral end face is dried and remains as it is, it contaminates the post-process equipment, and in particular, in recent years, the degree of integration tends to increase, and the yield further decreases. There was a problem.

Therefore, in the final stage of the step of spin-coating the thin film, a treatment for removing the unnecessary thin film on the peripheral end face of the rectangular substrate is performed in advance. As a technique for removing the unnecessary thin film, for example, there is one disclosed in Japanese Patent Publication No. 58-19350.

According to this conventional example, the cleaning liquid is discharged from a fixed position below the edge of the rectangular substrate while rotating the rectangular substrate after the spin coating at a low speed, and centrifugal force is applied to the rectangular substrate. The cleaning liquid cleans and removes the unnecessary thin film as it flows to the edge side, and the cleaning liquid also wraps around to the surface side of the edge of the rectangular substrate due to the surface tension, and the peripheral edge surface of the rectangular substrate and the rectangular substrate The unnecessary thin film formed on the edge of the surface is removed by washing, and after that, switching to high-speed rotation, the droplets are scattered outward by the centrifugal force from the liquid pool formed by washing, and the edge of the rectangular substrate The unnecessary thin films formed on both the front and back surfaces and the peripheral end surface on the edge side are cleaned and removed.

[0006]

However, the conventional example in which only the cleaning liquid is discharged from below the edge of the rectangular substrate has the following drawbacks.

When an organic solvent having a high volatility such as acetone is used as the cleaning liquid, there is little problem that the cleaning liquid remains due to the above-mentioned shaking off due to rotation and the ease of drying due to evaporation, but the temperature is lowered by the heat of vaporization. Is generated, and the vapor pressure of the cleaning liquid increases with evaporation, which makes the temperature and vapor pressure unstable and adversely affects the film thickness uniformity of the thin film formed on the rectangular substrate. It is preferable to use a cleaning liquid having a low viscosity, and as a result, it becomes difficult to dry due to vaporization, and there is a drawback that the cleaning liquid remains.

The present invention has been made in view of the above circumstances, and avoids the adverse effect on the thin film formed on the rectangular substrate, while the cleaning liquid is not left on the peripheral end surface of the rectangular substrate. It is an object of the present invention to enable good cleaning and removal of unnecessary thin films.

[0009]

The present inventor has discovered that, while repeating experiments using a cleaning liquid having a low volatility, there is regularity in the remaining part of the cleaning liquid.

The cleaning liquid spreads by centrifugal force during low speed rotation as in the prior art to clean the peripheral end face. After that, when the substrate is rotated at a high speed for shaking off, it is always gathered at the lower end of the edge of each substrate in the rotation direction. The cause of this is not clear, but due to the relationship between the adhesion between the substrate surface and the cleaning liquid and the centrifugal force depending on the number of revolutions, it is not possible to separate from the substrate, but there is a delay in the followability to the rotational movement of the substrate Infer.

The present invention has the following means for utilizing the above-mentioned reproducible phenomenon, applying a thin film having excellent uniformity using an organic solvent having low volatility, and eliminating residual cleaning liquid.

That is, a substrate holding means for mounting and holding a rectangular substrate having a thin film formed on its surface by spin coating so as to be rotatable about an axis in the vertical direction, and a rectangular substrate held by the substrate holding means. A cleaning liquid nozzle that is integrally rotatable and that discharges a cleaning liquid to the back surface of a rectangular substrate to clean and remove unnecessary thin films, and a gas nozzle that supplies gas to the corners on the back surface side of the rectangular substrate to blow away residual deposits. And is configured.

As the cleaning liquid to be used, when cleaning the photoresist coating liquid, cyclohexanone, diisobutyl ketone, butyl acetate, xylene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, dimethylformamide or the like is used. it can.

As the gas supplied from the gas nozzle, an inert gas such as nitrogen gas or air can be used.

[0015]

According to the structure of the substrate edge cleaning apparatus of the present invention, the rectangular substrate having a thin film uniformly formed on its surface by spin coating is placed and held on the substrate holding means and rotated, and the rear surface of the rectangular substrate is rotated. When the cleaning liquid is discharged onto the substrate, the cleaning liquid adhering to the rectangular substrate first wraps around the entire circumference of the substrate to perform cleaning. After that, if the cleaning liquid continues to rotate, the cleaning liquid moves along the substrate peripheral edge toward the lower rotation side end of each substrate edge until it is shaken off from the rectangular substrate by the centrifugal force due to the rotation. Accumulate on the side corner. After that, the remaining adhered cleaning liquid can be blown off and removed by the gas supplied from the gas nozzle.

[0016]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a partially cutaway overall side view showing an embodiment of a substrate edge cleaning apparatus according to the present invention. A rectangular substrate 1 having a thin film formed on its surface by spin coating is used as a vertical axis core. Substrate holding means 2 for rotatably mounting and holding it around P is provided, and the square substrate 1 is attached to the substrate holding means 2.
Is provided with a cleaning liquid nozzle 3 ...

The substrate holding means 2 is larger than the outer shape of the rectangular substrate 1 and rotates about the vertical axis P in a state where the rectangular substrate 1 is placed and held in a horizontal posture, and a rotary table 4 thereof. A group of a large number of substrate supporting pins 5 for supporting the substrate, which are erected on the rotating table 4 so that a gap is formed between the upper surface of the rotating table 4 and the lower surface of the rectangular substrate 1, and the rectangular substrate 1 The substrate holding pins 6 that come into contact with the corners from the outside and are positioned and held, and the rotating table 4 installed above the rotating table 4 in parallel with the rotating table 4.
And an upper rotating plate 7 that rotates together with the upper rotating plate 7.

On the upper surface of the outer periphery of the rotary table 4, a plurality of ring plates 9 are provided through spacer rings 8 having the same external dimensions as the rotary table 4, as shown in an enlarged side sectional view of a part of FIG. , While the upper support plate 1 is connected to the upper rotary plate 7.
0, the upper support plate 10 is detachably attached to the ring plate 9 via the knob bolts 11, and the thicknesses of the upper and lower washers 13 and 13 externally fitted to the connecting bolts 12 are set. A gap 14 corresponding to the above is formed above and below, and constitutes a drainage portion of the waste liquid surrounding the top and bottom of the rectangular substrate 1 and the radial outside of the rotary table 4, and the rotary table 4 and the upper rotary plate 7 form the rectangular substrate 1. The upper and lower narrow spaces are sandwiched so that they are integrally rotatable.

The upper rotary plate 7 is formed in a disk shape larger than the outer shape of the rectangular substrate 1, and is bolted to the lower surface of the upper support plate 10 via a collar 15 so that the upper rotary plate 7 and the rectangular substrate 1 have a constant small interval. They are parallel to each other (for example, about 10 mm).

A handle 16 for attachment / detachment is attached to the central upper surface of the upper rotary plate 7, and by removing the upper support plate 10, the rectangular substrate 1 and photoresist for forming a thin film are applied from the central opening of the ring plate 9. The coating liquid supply nozzle 17 for supplying the liquid can be taken in and out.

A waste liquid recovery case 18 is fixedly arranged around the lower part and the peripheral part of the above-mentioned rotating member, the bottom part of the waste liquid recovery case 18 is narrowed down, and a waste liquid discharge port 18a is formed at the lower end of the waste liquid recovery case 18 and the periphery thereof is formed. Exhaust ports 18b for exhausting the cleaning liquid gas evaporated from the coating liquid and the coating liquid mist are formed at a plurality of positions in the direction.

It is positioned below the rectangular substrate 1 supported by the substrate support pins 5 and, as shown in the plan view of the main part of FIG. The cleaning liquid nozzles 3 are attached to the rotary table 4 via the support stays 19 so that both ends of the cleaning liquid nozzles 3 are directed toward the rotary shaft core P, and are located near the middle of each side in the length direction. From the side to the one corner on the side in the rotational direction, the ejection holes 20 are formed with a predetermined interval in the longitudinal direction, and the ejection direction is directed to the rotational axis P side. The cleaning liquid is discharged to the half of the back side on the upper side in the rotational direction of the edge so that the unnecessary thin film on the peripheral end surface of the rectangular substrate 1 can be cleaned and removed.

The rotary table 4 is horizontally attached to an upper end of a hollow cylindrical vertical rotation shaft 21 which is vertically erected and driven to rotate, and is formed on the connection boss 22. The cleaning liquid is supplied to the cleaning liquid nozzles 3 through the first holes 23 and the internal space of the vertical rotation shaft 21.

As shown in the side sectional view of FIG. 2, gas nozzles 24 are attached to the rotary table 4 on the back surface side of the rectangular substrate 1 at positions near the four corners.

The gas nozzle 24 is shown in a perspective view of FIG. 4 (a) and a sectional view of FIG. 4 (b) [A in FIG. 4 (a)].
-A line cross-sectional view], it is configured by attaching a first gas supply pipe 26 having a bent tip end to the nozzle body 25, and as shown in FIG. 2, the first gas supply pipe 26,
The second hole 27 formed in the connection boss 22 is connected via the second gas supply pipe 26a.

As shown in FIG. 2, an annular hole 28 is formed at the lower end side of the connecting boss 22 and is sealed by attaching a lid member 30 via a packing 29, so that the second hole 27 is formed. And the annular hole 28 are connected, and the annular hole 28 is formed at a predetermined position in the circumferential direction.
Is connected to a third hole 31 that extends radially outward.

A nitrogen gas supply source is provided at a position facing the open end of the third hole 31 in a state where the substrate holding means 2 is stopped, through a flexible tube 34 having a pressure equalizing valve mechanism 32 and a solenoid valve 33. An intermediate member 35 connected to the intermediate member 35 is provided, an air cylinder 36 is interlockingly connected to the intermediate member 35, and a fourth hole 37 and a third hole 37 formed in the intermediate member 35 by extension of the air cylinder 36. 31 is connected, the solenoid valve 33 is opened, and nitrogen gas is supplied from the gas nozzle 24 to the corners on the back surface side of the rectangular substrate 1 to blow away the remaining deposits. 38 in the figure
Shows a seal ring that connects the fourth hole 37 and the third hole 31 in a sealed state.

With the above structure, the coating process is
First, the upper support plate 10 is lifted by an appropriate means to open the central opening largely, and the rectangular substrate 1 is placed horizontally on the substrate support pins 5 ... Group and held by the substrate holding pins 6.

Next, the coating liquid supply nozzle 17 is moved to the center of the central opening and lowered to an appropriate height on the rectangular substrate 1, and a predetermined amount of the coating liquid is dropped and supplied to the center of the rectangular substrate 1. .

After that, the coating liquid supply nozzle 17 is retracted, the upper support plate 10 is mounted and fixed to the ring plate 9, and the vertical rotation shaft 21 is driven to rotate the rotary table 4, the upper support plate 10 and the upper part. The square substrate 1 is horizontally rotated around the vertical axis together with the rotating plate 7. By this rotation, the coating liquid on the rectangular substrate 1 is diffused and flows outward by the centrifugal force, and is thinly coated on the upper surface of the rectangular substrate 1. In this case, the air in the space sandwiched between the rotary table 4 and the upper rotary plate 7 also rotates together with the rectangular substrate 1, and the coating liquid is applied to the rectangular substrate 1 without causing a wind-breaking phenomenon due to the peripheral edge of the rectangular substrate 1. 1 is uniformly applied to the upper surface.

Excess coating liquid flowing on the rectangular substrate 1 and reaching the outer periphery is formed as a mist from the peripheral edge of the rectangular substrate 1 to the peripheral portion of the space sandwiched between the rotary table 4 and the upper rotary plate 7. It scatters and flows into the waste liquid recovery case 18 through the gaps 14 formed above and below the spacer ring 8.

During such spin coating process, or
After the spin coating process is completed, the cleaning liquid is discharged to the edge on the back surface side of the rotating rectangular substrate 1 through the cleaning liquid nozzles 3 ... Flowing from the near position toward the outer peripheral side, wrapping around the peripheral end surface of the rectangular substrate 1 and being shaken off by the centrifugal force due to the rotation, along the substrate edge toward the lower side in the rotation direction of the substrate edge. Since it moves, the coating liquid mist adhering to the end surface of the rectangular substrate 1 or the coating liquid mist that is about to adhere is washed away, flows out to the waste liquid recovery case 18 through the gap 14 of the spacer ring 8, and only the waste liquid is discharged. The liquid is collected and discharged from the liquid port 18a.

After the cleaning process with the cleaning liquid, the rotation is stopped, the air cylinder 36 is extended to press the intermediate member 35 against the outer peripheral surface of the connecting boss 22, and the solenoid valve 33 is opened. Nitrogen gas is supplied to the parts to blow away the remaining deposits. That is, during the cleaning process with the cleaning liquid, the cleaning liquid receives the centrifugal force due to the rotation, and the cleaning liquid is applied to the rectangular substrate 1.
Flow toward the corners on the back surface of the sheet and stay at the corners. Further, in the rectangular rectangular substrate 1, it scatters from the rectangular substrate 1 and bounces from the peripheral portion and the upper surface of the turntable 4. The cleaning liquid easily concentrates and adheres to the corner of the long side of the rectangular substrate 1 on the lower side in the rotation direction, and the remaining adhered substances such as the cleaning liquid thus adhered and the above-mentioned accumulated cleaning liquid are blown off.

FIG. 5 shows a modification of the gas nozzle 24,
(A) is a perspective view, (b) is a sectional view [B- of (a) of FIG.
B line sectional view], the first gas supply pipe 26A attached to the nozzle body 25 has an inclined reflection surface F that becomes higher toward the corners, and a small diameter that discharges nitrogen gas toward the inclined reflection surface F. The hole 39 is provided, and the discharged nitrogen gas is reflected by the inclined reflection surface F and supplied to the corner portion of the back surface of the rectangular substrate 1.

In the above-described embodiment, the intermediate member 35 is displaced by the air cylinder 36 into a state in which it is pressed against the connecting boss 22 and a state in which it is separated, and nitrogen gas is supplied when rotation is stopped. In place of the displacement structure by the air cylinder 36 as described above, a cylindrical body is provided which rotatably fits the coupling boss 22 in a sealed state, and the inner peripheral surface of the cylindrical body and the outer peripheral surface of the coupling boss 22 are provided. A so-called rotary joint configuration may be adopted in which the gas flow path is formed so as to be constantly connected between the two. Further, paying attention to the fact that the supply of nitrogen gas is when the rotation of the rectangular substrate 1 is stopped, the gas nozzle 24 may be provided in a fixed state apart from the back surface of the rectangular substrate 1.

In the above embodiment, the nitrogen gas is supplied to each of the four corners of the rectangular substrate 1. However, for example, the rectangular rectangular substrate 1 is provided on the back surface of the rectangular substrate 1. When the cleaning liquid is supplied only to the two corners on the lower side in the rotation direction of the long side, the nitrogen gas may be supplied only to the two corners supplying the cleaning liquid. .

In the above-mentioned embodiment, the substrate edge cleaning device is incorporated in the spin coating device for supplying the photoresist coating liquid to the surface of the rectangular substrate 1 to spin-coat it. Separately, a square substrate 1 having a thin film formed by spin coating with a spin coating device is carried in by a suitable transporting means without contamination and the edge of the square substrate 1 is cleaned. It may be configured to blow off the remaining deposits with a gas.

Further, in the above embodiment, in order to mount and hold the rectangular substrate 1, the contact area with respect to the rectangular substrate 1 at the time of mounting and holding is set by the substrate supporting pins 5 ... And the substrate holding pins 6. Although the configuration is made as small as possible, the present invention may be configured to hold the rectangular substrate 1 by vacuum suction, for example.

In the above embodiment, the substrate holding means 2
Is provided with an upper rotary plate 7 that rotates integrally with the rectangular substrate 1 to avoid the influence of the air flow associated with the rotation and adversely affect the film thickness distribution of the thin film formed on the surface of the rectangular substrate 1. The present invention is configured so that it can be washed without giving it.
It may be configured so as to be washed with the surroundings open.

[0041]

As is apparent from the above description, according to the substrate edge cleaning device of the present invention, the cleaning liquid is discharged to the back surface of the rotating rectangular substrate, so that the cleaning liquid is directed to the peripheral edge surface of the substrate. Wrap it around to clean and remove unnecessary thin films, and then blow off the cleaning liquid remaining on the corners and remaining and adhering by the gas supplied from the gas nozzle.Therefore, even if a cleaning liquid with low volatility is used, the cleaning liquid remains It is possible to avoid remaining on the corners on the back side of the rectangular substrate, and as in the case of using a highly volatile cleaning liquid, it is caused by the temperature decrease due to the heat of vaporization due to volatilization and the increase in vapor pressure due to the volatile vapor. It is possible to satisfactorily clean and remove unnecessary thin films on the peripheral edge surface of the rectangular substrate without leaving the cleaning liquid while avoiding adverse effects on the thin film formed on the rectangular substrate, such as unstable film thickness distribution. They became.

[Brief description of drawings]

FIG. 1 is a partially cutaway overall side view showing an embodiment of a substrate edge cleaning device according to the present invention.

FIG. 2 is an enlarged side view of a main part.

FIG. 3 is a plan view of a main part.

4A is a perspective view of a gas nozzle, and FIG. 4B is a sectional view taken along the line AA of FIG.

FIG. 5A is a perspective view showing a modified example of the gas nozzle,
FIG. 6B is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rectangular substrate 2 ... Substrate holding means 3 ... Cleaning liquid nozzle 24 ... Gas nozzle P ... Vertical axis

Claims (1)

[Claims] 1. A substrate holding means for mounting and holding a rectangular substrate having a thin film formed on its surface by spin coating so as to be rotatable about an axis in the vertical direction, and the rectangular substrate held by the substrate holding means. A cleaning liquid nozzle that is rotatably integrated with the rectangular substrate to discharge a cleaning liquid to the back surface of the rectangular substrate to clean and remove unnecessary thin films; A substrate edge cleaning device equipped with a gas nozzle that blows away gas.