JP2507966B2 - Coating device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus, and more particularly to a coating apparatus for a chemical solution used for thin film formation in semiconductor manufacturing processes, liquid crystal substrate manufacturing processes and the like.

[0002]

2. Description of the Related Art A conventional coating apparatus has a function of supplying a solvent to a nozzle portion as shown in a piping system diagram of the nozzle portion in FIG. 6 (Japanese Patent Laid-Open No. 2-307214). That is, when discharging the chemical liquid during the coating process of the chemical liquid, the nozzle 1 moves to directly above the semiconductor substrate or the like which is the object to be processed placed in the coating cup (not shown).
Shows the case where the nozzle 1 is in the standby position where the chemical solution is not discharged.

Normally, the nozzle 1 is used to apply a chemical solution to a substrate.
Further, a certain amount of the chemical liquid is discharged onto the substrate which is the object to be processed, and the substrate is rotated at a constant speed to form a thin film. At the standby position as shown in FIG. 6, the nozzle 1 is exposed to the outside air as it is, and the chemical liquid remaining at the tip of the nozzle is dried and solidified. This solidified chemical solution drops on the substrate as the chemical solution is discharged, causing uneven coating of the coating film.
It is necessary to take measures such as filling the nozzle tip with a solvent atmosphere of the chemical liquid.

In the prior art shown in FIG. 6, in consideration of this point, a method of spraying the solvent vapor to the tip portion of the nozzle in the nozzle standby portion is adopted. That is, in FIG. 6, the solvent 3 in the solvent container 2 is bubbled through the nitrogen pipe 4, and the solvent vapor generated by the bubbling is ejected from the ejection port 6 to the tip of the nozzle 1 through the vapor pipe 5. Therefore, the periphery of the tip of the nozzle 1 is filled with the solvent atmosphere.

[0005]

In the conventional coating apparatus,
Since the nozzle 1 has to move onto the substrate when performing the coating process, a time outside the ejection port 6, that is, a time during which the nozzle 1 is exposed to the outside air occurs. Generally, this time is relatively short, about 5 seconds, excluding the time for discharging the chemical solution, but since the cumulative time increases as the number of substrates processed increases, the tip portion of the nozzle 1 may be removed while the coating process is in progress. There is a problem that the dried and solidified chemical solution gradually adheres and grows, and finally drops onto the substrate at the same time as the chemical solution is discharged to cause contamination of the substrate and uneven coating of the thin film.

In particular, among the coating chemicals, a silica liquid or the like, which is extremely prone to solute deposition due to drying, causes solute deposition even during the above-described nozzle movement time, and contaminates the substrate after each coating process. It was necessary to clean the tip of the nozzle with a solvent every time before the coating process. With this cleaning operation, the chemical liquid at the tip of the nozzle frequently comes into contact with the solvent, and as a result, the chemical liquid is diluted by the solvent, so a certain amount of chemical liquid had to be discharged from the nozzle after cleaning the nozzle. . Since the amount thereof generally corresponds to about half of the chemical liquid used for coating, there is a problem that the chemical liquid used is about 1.5 times the chemical liquid amount used for coating treatment.

Further, in any of the chemicals, the bubbling of the solvent has to be constantly performed except during the coating process, that is, while the nozzle is waiting, so that there is a problem that the consumption amount of the solvent increases.

[0008]

A coating apparatus of the present invention comprises a nozzle block surrounding a nozzle and having a lower end opened, and a porous solvent pool held in the nozzle block and covering the nozzle tip. A solvent supply pipe for supplying a solvent to the porous solvent reservoir and a nitrogen delivery pipe for delivering nitrogen to a gap provided between the porous solvent reservoir and the outer peripheral portion of the nozzle are connected to the nozzle block. .

[0009]

The present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a nozzle portion in an embodiment of the coating apparatus of the present invention. In FIG. 1, the nozzle 1 for discharging the chemical liquid is covered with a porous solvent pool 7 made of a hollow cylindrical sponge material, and the outer peripheral portion of the nozzle 1 and the porous solvent pool 7 do not come into contact with each other. A gap portion 8 is provided in. The nozzle block 9 is a cylindrical container that holds the porous solvent pool 7 inside, and a circular hole-shaped opening 1 at the bottom.
0 is provided so as not to interfere with the discharge of the chemical liquid from the nozzle 1. For the same reason, the porous hollow space 7 is also provided with a hollow cylindrical portion 11.

A solvent supply pipe 12 connected to the upper portion of the nozzle block 9 is a pipe for supplying the solvent 3 such as acetone or ethanol to the porous solvent reservoir 7, and the nitrogen delivery pipe 13 is a gap portion 8 and a cylinder. This is a purging pipe for discharging the solvent 3 accumulated in the hollow portion 11 with nitrogen. The waste liquid port 14 is a conduit for discharging the waste liquid of the chemical liquid or the solvent to the outside. FIG. 1 shows that the nozzle portion is in the standby position when the coating process is not performed.

Next, the operation of the nozzle section shown in FIG. 1 will be described with reference to FIG.
~ It demonstrates by FIG. 2 to 5 are first to fourth process charts showing the procedure of the coating process in this embodiment. In each drawing, FIG. (A) shows a sectional view of the standby portion, and FIG. (B) shows a sectional view of the coating processing portion. As shown in each drawing (b), the coating cup 15 is a container for capturing splashes of the chemical solution generated during the coating process, and the rotary chuck 16 is for fixing and rotating the substrate 17 by suction.

First, in the standby portion of FIG. 2A, when the solvent 3 is discharged from the solvent supply pipe 12 before the coating process, the solvent 3 wets the porous solvent pool 7, and the gap 8 and the cylinder. While cleaning the tip of the nozzle 1 along the hollow portion 11, it drops from the opening 10 to the waste liquid outlet 14. The first step is a step of replenishing the solvent in the porous solvent reservoir 7 and washing contaminants such as solids of the chemical liquid adhering to the tip of the nozzle 1.

Next, when the substrate 17 is set in the coating cup 15 in the coating section of FIG. 3B, nitrogen is delivered from the nitrogen delivery pipe 13 in the standby section of FIG. 3A, In the above-mentioned first step, the unnecessary solvent that is likely to collect and drop in the gap 8 and the hollow cylindrical portion 11 is discharged. Then, after this operation is completed, a certain amount of the chemical liquid 18
Is discharged to the waste liquid port 14. FIG. 3A shows the second step of discharging the chemical liquid 18 diluted with the solvent. The reason for this discharge is that the solvent in the vicinity of the tip of the nozzle 1 enters the inside of the nozzle 1 and dilutes the chemical liquid when the solvent is replenished in the first step.

Next, in the third step, as shown in the coating processing section of FIG. 4B, the nozzle 1 is moved to the upper portion of the substrate 17 and the chemical liquid 18 is discharged. Then, the substrate 17 is rotated by the rotary chuck 16 to complete the coating process. When the coating process is completed, the nozzle 1 returns to the upper position of the waste liquid port 14 and waits as a fourth step, as shown in FIG.

Here, when a certain number of substrates 17 are to be continuously processed, the above-mentioned third and fourth steps shown in FIGS. 4 (b) and 5 (a) are repeated. Then, when the substrate 17 is not present in the coating processing section of FIG. 5B, the nozzle 1 waits at the position of FIG. 5A until the substrate 17 arrives again. When the need for the coating process arises, the operation is started again from the first step in FIG.

In this embodiment, since the porous solvent pool 7 contains the solvent therein in each of the second, third and fourth steps shown in FIGS. The tip portion of 1 is exposed to a solvent vapor atmosphere that evaporates from the porous solvent pool 7. This solvent vapor is applied to the opening 10 of the nozzle block 9.
Although it flows out more to the outside, it is sequentially supplied to the gap 8 and the cylindrical hollow portion 11 by volatilization from the porous solvent pool 7 containing a sufficient amount of solvent, so that the tip of the nozzle 1 is exposed to the solvent vapor atmosphere. Will be satisfied. Also, since the solvent used is an organic solvent such as acetone and ethanol,
It easily becomes saturated vapor at room temperature. However, since the solvent contained in the porous solvent pool 7 gradually decreases due to volatilization, if the standby state of the nozzle 1, that is, the state of the fourth step shown in FIG. Two
The solvent supply operation of the first step shown in (a) is required.

The operation procedure and action have been described above. The major difference of this embodiment from the prior art is that the nozzle is not in the standby position, that is, the nozzle is moving between the coating processing section and the standby position. Even if it is in the coating processing part, the point that the nozzle is filled with a solvent atmosphere to prevent the chemical liquid from drying at the tip of the nozzle and that the supply operation of the solvent that is the source of the solvent atmosphere and the cleaning of the nozzle by the solvent can be performed at the same time. That is the point. Therefore, it is not necessary to discharge the chemical liquid such as silica liquid from the nozzle for each coating process. Conventionally, the ratio of the discharged amount of the silica liquid or the like was about 1/3 of the total used amount, so that the used amount of the silica liquid or the like can be reduced to about 2/3 of the conventional amount by this embodiment.

In the case of chemicals such as photoresists, conventionally, the coating failure of the substrate due to the drying of the chemicals at the tip of the nozzle has occurred at a rate of about 1% of the total number of treatments. However, in this embodiment, since the nozzle tip can be always placed in the solvent atmosphere, this coating failure can be eliminated.

Further, the amount of the solvent used to evaporate by the bubbling method is about 100 cc / hour in order to prevent the nozzle tip from drying, whereas in this embodiment, the solvent is intermittently stored in the porous solvent pool. Since it is a method of supplying,
The consumption is about 10 cc / hour. Therefore, the consumption amount of the solvent can be reduced to about 1/10 as compared with the conventional method.

[0020]

As described above, according to the present invention, a porous solvent pool is provided at the tip of the nozzle, and the solvent is intermittently supplied thereto so that the nozzle tip always has a solvent atmosphere,
Since the chemical liquid is prevented from drying, it is not necessary to discharge the silica liquid etc. for each coating process. Therefore, the amount of the chemical solution used can be reduced.

Further, it is possible to eliminate the coating failure of the substrate due to the fall of the dried and solidified material which is generated in the chemical liquid such as the photoresist.

Further, instead of the bubbling system of the solvent, the system of intermittent supply of the solvent to the porous solvent pool is adopted, so that the consumption amount of the solvent can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a nozzle portion in an embodiment of a coating apparatus of the present invention.

FIG. 2 is a diagram showing a first step of a coating process according to an embodiment of the present invention, in which FIG. 2 (a) is a sectional view of a standby portion and FIG. 2 (b).
[FIG. 4] is a cross-sectional view of a coating processing section.

FIG. 3 is a diagram showing a second step of the coating process in one embodiment of the present invention, in which FIG. 3 (a) is a sectional view of a standby portion and FIG. 3 (b).
[FIG. 4] is a cross-sectional view of a coating processing section.

FIG. 4 is a diagram showing a third step of the coating process in one embodiment of the present invention, where FIG. 4 (a) is a cross-sectional view of a standby portion and FIG. 4 (b).
[FIG. 4] is a cross-sectional view of a coating processing section.

5A and 5B are diagrams showing a fourth step of the coating process in one embodiment of the present invention, in which FIG. 5A is a sectional view of a standby portion and FIG.
[FIG. 4] is a cross-sectional view of a coating processing section.

FIG. 6 is a piping system diagram of a nozzle portion in a conventional coating device.

[Explanation of symbols]

 1 Nozzle 2 Solvent Container 3 Solvent 4 Nitrogen Piping 5 Steam Piping 6 Spout 7 Porous Solvent Reservoir 8 Gap 9 Nozzle Block 10 Opening 11 Cylindrical Hollow 12 Solvent Supply Piping 13 Nitrogen Delivery Piping 14 Waste Liquid Port 15 Coating Treatment Cup 16 Rotating chuck 17 Substrate 18 Chemical solution

Claims (3)

(57) [Claims] 1. A coating device for forming a thin film having a predetermined thickness by discharging a chemical solution from a nozzle onto a surface of a substrate, and a nozzle block surrounding the nozzle and having an open lower end, and a nozzle block held in the nozzle block. A porous solvent pool covering the tip of the nozzle is provided, and a solvent supply pipe for supplying a solvent to the porous solvent pool, and nitrogen in a gap portion provided between the porous solvent pool and the outer peripheral portion of the nozzle. A coating device, wherein a nitrogen delivery pipe for delivering is connected to the nozzle block. 2. The coating apparatus according to claim 1, wherein a porous solvent reservoir containing the solvent is provided so as to surround the nozzle tip portion. 3. The coating apparatus according to claim 1, wherein the nitrogen delivery pipe is a purge pipe for discharging the solvent remaining at the tip of the nozzle.