JP2002143749A - Rotary coater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary coater which can wash the inner wall surface of a spin cup uniformly while reducing the usage of a cleaning liquid and can wash the spin cup without sophisticating a device configuration and decreasing productivity. SOLUTION: This rotary coater is provided with spray nozzles 34, 34 for spraying a cleaning liquid toward the inner wall surface 24a of a spin cup 24, and a cup rotating mechanism for rotating the spin cup 24 with respect to the spray nozzles 34, 34. The cleaning liquid is widely and uniformly sprayed onto the inner wall surface 24b of the cup to wash the surface, thereby suppressing the usage of the cleaning liquid, realizing efficient washing by a simple device configuration, and reducing a washing time to prevent the deterioration in productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spin coating apparatus for spin-coating a coating liquid such as a photoresist or a developing solution on a substrate to be processed, for example, a semiconductor wafer. The present invention relates to a spin coating apparatus having a cup cleaning function of cleaning an inner wall surface of a spin cup contaminated with a coating liquid to be cleaned.

[0002]

2. Description of the Related Art In a process of applying a coating solution such as a photoresist or a developing solution to a substrate to be processed (hereinafter simply referred to as a substrate) such as a semiconductor wafer, a spin coating device called a spin coater or a spinner is used. ing. As is well known, a coating film having a uniform thickness is formed on a substrate by holding and rotating the substrate horizontally by a rotation holding means provided with a spin chuck at an upper end of a rotation shaft arranged in a vertical direction. It is a device to do.

In general, the spin coating apparatus is provided with a cylindrical spin cup so as to surround the periphery of the substrate.
Spray of the coating solution scattered from around the substrate is attached to the inner wall surface of the spin cup, thereby preventing contamination around the device.

However, in the case of a coating liquid such as a photoresist which solidifies upon drying, if the processing of the substrate is continued while the coating liquid adheres to the inner wall surface of the spin cup, vibrations of the apparatus caused by rotation of the substrate may be caused. Due to the collision with the splash of the scattered coating liquid, the dried and solidified coating liquid may peel off from the inner wall surface of the spin cup and fly to the substrate, resulting in defective products.

In order to solve such a problem, various spin coating apparatuses having a function of washing and removing a coating solution adhered to the inner wall surface of a spin cup have been proposed.

For example, Japanese Utility Model Publication No. 6-28223 discloses that
As shown in FIG. 4, an annular cleaning conduit 5 for storing the cleaning liquid 4 and a plurality of discharge holes 6 for the cleaning liquid 4 are formed on the outer surface of the spin cup 3 provided around the substrate 2 on the rotation holding means 1. By doing so, a configuration is disclosed in which the cleaning liquid 4 is caused to flow down along the inner peripheral surface of the spin cup 3 to wash and remove the applied coating liquid. The cleaning liquid 4 is applied to the upper part of the inner surface of the rectifying plate 7 in order to wash and remove the coating liquid adhering to the outer surface of the rectifying plate 7 having a truncated cone shape that guides the flow of air between the substrate 2 and the spin cup 3. By forming the annular cleaning conduit 8 and a plurality of discharge holes 9 for the cleaning liquid 4 to be stored, the cleaning liquid 4 is discharged from the discharge holes 9 to the rectifying plate 7.
There is also disclosed a configuration for flowing down along the outer surface of the.

On the other hand, Japanese Patent No. 2814184 discloses that
As shown in FIG. 5, the cleaning jig 12
A configuration is disclosed in which is fixed and the coating liquid is washed to remove the coating liquid adhering to the inner wall surface of the spin cup 13 by rotating it. That is, the cleaning jig 12 has an annular storage portion 16 for storing the cleaning liquid 15 supplied from the cleaning liquid supply nozzle 14 disposed below the cleaning jig 12. From the hole 17 of the spin cup 13 using centrifugal force generated by the rotation of the cleaning jig 12.
The cleaning liquid 15 is spouted toward the inner wall surface of the nozzle.

In Japanese Patent No. 3015207 and Japanese Patent No. 2893149, a discharge hole for a cleaning liquid is provided in the rotation holding means, and the rotation holding means is rotated toward the inner wall surface of the spin cup by utilizing the centrifugal force generated by rotation. A configuration for ejecting a cleaning liquid is disclosed.

[0009]

However, as described in Japanese Utility Model Publication No. Hei 6-28223, the cleaning liquid is caused to flow down along the inner wall surface of the spin cup for cleaning.
Since the cleaning liquid 4 easily flows along the path once flowing, the cleaning liquid 4 flows through the inner wall surface of the spin cup 3 from the discharge hole 6 through a certain path, and the inner surface of the spin cup 3 cannot be uniformly cleaned. There is a problem. Also,
There is a problem in that a large amount of cleaning solution is required.

On the other hand, in the configuration described in Japanese Patent No. 2814184, since the cleaning jig 12 needs to be mounted on the rotation holding means 11 instead of the substrate, the spin cup 13 is cleaned. The process takes a great deal of time, greatly reducing productivity. In addition, in this configuration, since the cleaning liquid 15 is ejected by using the centrifugal force generated by the rotation of the cleaning jig 12, the rotation speed of the cleaning jig 12 needs to be relatively high. In this case, the cleaning liquid 15 can always be supplied only to a fixed position with respect to the inner wall surface of the spin cup 13. Therefore, it is impossible to evenly supply the cleaning liquid 15 to the inner wall surface of the spin cup 13, so that the cleaning becomes uneven and an efficient cleaning action cannot be obtained.

[0011] Further, the configurations described in the above-mentioned Japanese Patent Nos. 3015207 and 2893149 not only complicate the configuration of the rotation holding means, but also deteriorate the maintainability of the apparatus and prolong the maintenance time. , Resulting in a problem of lowering productivity. In addition, since the cleaning liquid is ejected toward the inner wall surface of the spin cup by using the centrifugal force generated by the rotation of the rotation holding means, the same problem as described above is included.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to uniformly clean the inner surface of a spin cup while reducing the amount of a cleaning solution used, and to improve the productivity without complicating the apparatus configuration. It is an object of the present invention to provide a spin coating apparatus that can wash a spin cup without lowering the spin coating apparatus.

[0013]

In order to solve the above problems, a spin coating apparatus according to the present invention comprises: a spray nozzle for spraying a cleaning liquid toward an inner wall surface of a spin cup; And a cup rotating mechanism for rotating the cup.

In the present invention, the use of the spray nozzle makes it possible to supply the cleaning liquid uniformly over a wide area of the inner surface of the spin cup, and drives the cup rotating mechanism to move the spin cup to the spray nozzle. By rotating, the cleaning liquid can be supplied uniformly over the entire inner wall surface of the spin cup. As a result, the entire circumference of the spin cup can be cleaned over a wider area with a smaller amount of cleaning liquid than before, and an efficient cleaning action can be obtained.

The spin coating apparatus of the present invention can be configured without complicating the inside of the spin cup, so that the maintainability of the apparatus is not impaired. In addition, if a plurality of the spray nozzles are provided, the time for supplying the cleaning liquid to the entire inner wall surface of the spin cup can be reduced, and as a result, the cleaning time can be shortened and the productivity can be prevented from lowering.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a case will be described in which the present invention is applied to a spin coating apparatus that spin-coats a photoresist on a semiconductor wafer (hereinafter, simply referred to as a substrate).

FIGS. 1 and 2 show a spin coating apparatus according to a first embodiment of the present invention. The spin coating apparatus 20 according to the present embodiment includes a spin holder 24 that holds and rotates the substrate W horizontally, and a cylindrical spin cup 24 that is disposed so as to surround the periphery of the substrate W and has a truncated conical cross section. And

The rotation holding unit 23 includes a rotation drive unit 22 having a rotation shaft 22a arranged in a vertical direction, and a rotation shaft 22a.
And a vacuum chuck spin chuck 21 which is fixed to the upper end of the substrate and horizontally holds the substrate W.

When the substrate W is suction-held on the spin chuck 21 of the rotation holding unit 23 with the processing surface facing upward via a transfer arm (not shown), a predetermined amount of photoresist is applied onto the substrate W from the coating solution nozzle 36. The supplied photoresist spreads radially outward by driving the rotation driving unit 22 to rotate the substrate W at a predetermined number of revolutions, and a resist film having a uniform thickness is formed on the upper surface of the substrate W. Is formed. At this time, the excess photoresist scattered outward from the periphery of the substrate W is deposited on the inner wall surface 24 of the spin cup 24.
b, and contamination around the device 20 is prevented.

Next, the cup rotating mechanism according to the present invention will be described.

In the present embodiment, the spin cup 24
It has a structure in which the rotation holding unit 23 is mounted on a cup support plate 25 through which the rotation holding unit 23 passes through a bearing member 26.
The cup support plate 25 is provided with an exhaust pipe 26 communicating with an exhaust means such as a vacuum pump (not shown) and an excess liquid of a coating liquid (photoresist) discharged from a coating liquid nozzle 36 into the apparatus 2.
0 is connected to a waste liquid pipe 27 for discharging to the outside. The bearing member 26 is formed of the cup support plate 2 having the above-described configuration.
5 is provided over the entire periphery 25a. On the other hand, an annular flange portion 24a attached to the upper surface of the bearing member 26 is formed on the outer peripheral portion of the peripheral wall of the spin cup 24.
Are rotatable relative to the cup support plate 25.

The rotation of the spin cup 24 is performed by driving a drive motor 32 disposed near the spin cup 24. That is, on the outer periphery of the flange portion 24a of the spin cup 24, a tooth portion 29 that meshes with the gear 31 connected to the drive shaft 32a of the drive motor 32 is provided over the entire periphery, whereby the driving force of the drive motor 32 is provided. Is transmitted to the spin cup 24, and the spin cup 24 rotates with respect to the cup support plate 25. As described above, the cup rotating mechanism according to the present invention is configured. In addition, tooth part 2
At the lower end of 9, a guide portion 30 for guiding the proper rotation of the spin cup 24 is provided.

At the position below the substrate W, a fixing base 33 for fixing two spray nozzles 34, 34 for spraying the cleaning liquid toward the inner wall surface 24b of the spin cup 24 is attached to the cup support plate 25. ing. The spray nozzles 34, 34 are constituted by known spray guns which spray the cleaning liquid supplied via the supply pipes 34 a, 34 a in a mist toward a predetermined range of the inner wall surface 24 b of the spin cup 24, and the present embodiment. In the example, the cleaning liquids are arranged to be sprayed in mutually opposite directions at positions symmetrical with respect to the center of the spin cup 24 (ie, at 180-degree intervals).

Further, three back rinse nozzles 35, 35, 35 for discharging the cleaning liquid toward the back surface of the substrate W are fixed at intervals of 120 degrees on the radially inner side from the arrangement positions of the spray nozzles 34, 34. It is arranged so as to protrude from the upper surface of the table 33, and is configured to wash and remove the photoresist adhered to the back surface of the substrate W. Further, a rectifying plate 33 a for guiding the flow of air inside the spin cup 24 is integrally formed on the outer peripheral portion of the fixed base 33.

The spin coating apparatus 20 of the present embodiment is configured as described above.
The action of cleaning the inner wall surface of No. 4 will be described.

The photoresist droplets scattered from the periphery of the substrate W adhere to the inner wall surface 24b of the spin cup 24 of the spin coating device 20 for performing the spin coating of the substrate W in the manner described above. Drying and solidification causes dust, so it is necessary to periodically clean the inner wall surface 24b. In the present embodiment, each time a predetermined number of substrates W are processed, the inner wall surface 24b of the spin cup 24 is cleaned by the following operation.

The inner wall surface 24b of the spin cup 24 is cleaned by spraying two spray nozzles 3 toward the inner wall surface 24b.
While the cleaning liquid is being sprayed from the
Is driven to rotate the spin cup 24 relative to the cup support 25 at a relatively low speed. The cleaning liquid L sprayed by the spray nozzles 34, 34 is sprayed over a wide range and evenly on the inner wall surface 24b of the spin cup 24. In addition, since the spin cup 24 is relatively rotated with respect to the spray nozzles 34, 34, the cleaning liquid L is sprayed evenly over the entire inner wall 24b to which the photoresist droplets adhere.

Thus, the inner wall surface 2 of the spin cup 24
The photoresist adhering to 4b is washed and removed. The washed-out photoresist is discharged to the outside of the apparatus 20 through the waste liquid pipe 28, or is discharged to the outside of the apparatus 20 together with the air inside the spin cup 24 through the exhaust pipe 27.

Therefore, according to the present embodiment, the inner wall surface 24b of the spin cup 24 can be efficiently cleaned with a simple configuration, and the cleaning liquid is sprayed onto the spray nozzles 34, 34.
Since the spraying is performed at 34, the amount of the cleaning liquid used can be reduced as compared with the conventional case, and the cleaning cost can be reduced.

Further, according to the present embodiment, the cleaning liquid is evenly applied to the entire inner wall surface 24b of the spin cup 24 only by rotating the spin cup 24 by a rotation angle corresponding to the arrangement interval of the spray nozzles 34, 34. Can be supplied, so that the cleaning time can be shortened, and a decrease in productivity can be prevented.

On the other hand, in the present embodiment, a plurality of back rinse nozzles 35 for supplying the cleaning liquid to the back surface of the substrate W are arranged at equal angular intervals. It is possible to clean the entire upper surface of the current plate 33a with the cleaning liquid scattered during the cleaning. Thus, it is possible to prevent the photoresist attached to the upper surface of the current plate 33a from drying and solidifying to cause dust.

FIG. 3 shows a second embodiment of the present invention. In the drawings, the same reference numerals are given to portions corresponding to the above-described first embodiment, and a detailed description thereof will be omitted.

The spin coating device 40 according to the present embodiment is
The first embodiment is different from the first embodiment in that one of the two spray nozzles 34, 34 in the first embodiment described above is provided with a cleaning liquid drying unit configured by a spray nozzle 41 for injecting nitrogen gas (N2) or dry air M. This embodiment is different from the embodiment.
Other configurations are the same as in the first embodiment.

According to this configuration, one of the spray nozzles (left side in FIG. 3) 34 causes the spin cup 24 to rotate.
The cleaning liquid L is supplied to the inner wall surface 24b, and the other spray nozzle (right side in FIG. 3) 41 is used to immediately dry the inner wall surface 24b supplied with the cleaning liquid L with nitrogen gas or dry air M.

Accordingly, compared to the first embodiment, the drying time of the cleaning liquid can be reduced, and the productivity can be further prevented from lowering.

Although the embodiments of the present invention have been described above, the present invention is, of course, not limited to these embodiments.
Various modifications are possible based on the technical idea of the present invention.

For example, in the above-described first embodiment, two spray nozzles 34 for spraying the cleaning liquid L and three back rinse nozzles 35 are provided, but it is needless to say that the present invention is not limited to this. The number can be increased or decreased.

In the above-described second embodiment, the spray nozzle 34 for spraying the cleaning liquid L and the spray nozzle 41 for spraying the nitrogen gas or dry air M are separately provided. And nitrogen gas (dry air) may be sequentially injected.

In this case, a supply pipe (corresponding to a reference numeral 34a in FIG. 1) of a spray nozzle is arranged in a tank storing a cleaning liquid for one cleaning treatment, and the pressurizing action of nitrogen gas or dry air fed into the tank. If the cleaning liquid is sprayed, the cleaning liquid, a mixture of the cleaning liquid and nitrogen gas (dry air), and a nitrogen gas (dry air) are continuously jetted from one spray nozzle in accordance with the remaining amount of the cleaning liquid. be able to.

Further, in each of the above embodiments, the cleaning liquid L
Although the spray angle of the spray nozzle 34 for spraying is fixed, the cleaning liquid can be sprayed over a wider area on the inner wall surface 24b of the spin cup 24 by making the spray angle variable.

[0041]

As described above, according to the spin coating apparatus of the present invention, the inner wall surface of the spin cup can be efficiently cleaned with a simple configuration, and the cleaning liquid is sprayed by the spray nozzle. Therefore, the amount of the cleaning liquid used can be reduced as compared with the conventional case, and the cleaning cost can be reduced. Further, the cleaning time can be shortened, and a decrease in productivity can be prevented.

According to the second aspect of the present invention, it is possible to prevent the apparatus configuration from becoming complicated and to easily implement the present invention by partially improving existing facilities.

According to the third aspect of the present invention, the spin cup cleaning time can be greatly reduced, and the productivity can be improved.

According to the fourth aspect of the present invention, the cleaning liquid can be dried with a simple configuration, and the configuration of the apparatus can be prevented from becoming complicated.

According to the fifth aspect of the present invention, it is possible to prevent the photoresist adhering to the upper surface of the current plate from drying and solidifying to cause dust.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a spin coating device according to a first embodiment of the present invention.

FIG. 2 is a plan view of the same, in which a fixing stand 33 is not shown in FIG. 1;

FIG. 3 is a side sectional view of a spin coating device according to a second embodiment of the present invention.

FIG. 4 is a partially broken side view showing a conventional spin coating device.

FIG. 5 is a side sectional view showing another conventional spin coating apparatus.

[Explanation of symbols]

20, 40 ... spin coating device, 23 ... spin holder, 24 ...
Spin cup, 24b ... inner wall surface of spin cup, 29 ...
Tooth, 31 ... Gear, 32 ... Drive motor, 34, 41 ... Spray nozzle, 35 ... Back rinse nozzle, W ... Substrate (substrate to be processed).

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/30 502 G03F 7/30 502 H01L 21/027 H01L 21/30 564C 569F F-term (Reference) 2H025 AA00 AB16 EA05 FA14 2H096 AA00 AA25 CA14 GA29 GA31 GA32 4D075 AC64 AC79 BB20Z BB24Z BB65Z DA06 DC22 4F042 AA07 CC04 CC07 CC10 DC00 EB09 EB11 EB24 EB25 5F046 JA02 JA05 JA11 LA04 LA06

Claims (5)

[Claims] 1. A spin coating apparatus comprising: a spin holder that horizontally holds and rotates a substrate to be processed; and a spin cup disposed around the substrate to be processed. A spray nozzle for spraying the cleaning liquid by spraying, and a cup rotating mechanism for rotating the spin cup with respect to the spray nozzle. 2. The apparatus according to claim 1, wherein the cup rotating mechanism includes teeth formed on the entire outer periphery of the spin cup, a gear meshing with the teeth, and a drive motor for rotating the gear. The spin coating device according to claim 1. 3. The spin coating apparatus according to claim 1, further comprising cleaning liquid drying means for drying the cleaning liquid sprayed on the inner wall surface of the spin cup. 4. The spin coating apparatus according to claim 3, wherein said cleaning liquid drying means is an air or nitrogen gas injection nozzle. 5. A rectifying plate for guiding the flow of air inside the spin cup, and a back rinse nozzle for supplying a back surface cleaning liquid to the back surface of the substrate to be processed, 2. The spin coating device according to claim 1, wherein a plurality of the back rinse nozzles are provided at equal angular intervals in order to wash the upper surface of the current plate with the scattered back surface cleaning liquid. 3.