JP3039820B2 - Coating device and coating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coating apparatus and a coating method .

[0002]

2. Description of the Related Art Conventionally, coating apparatuses for applying a photoresist solution, a developing solution or the like to an object to be coated, such as a semiconductor wafer, have been widely used. FIG. 4 shows a configuration of a conventional resist coating apparatus that applies a photoresist liquid to a semiconductor wafer as an example of such a coating apparatus.

As shown in FIG. 1, the resist coating apparatus is provided with a spin chuck 2 configured to hold a semiconductor wafer 1 to be coated by a vacuum chuck or the like and to rotate the semiconductor wafer 1 at a high speed. Around the spin chuck 2, a cup 3 for preventing the photoresist liquid from scattering is provided. A resist supply nozzle 4 is provided above the spin chuck 2.

[0004] The resist supply nozzle 4 is connected to a resist supply pipe 5.
Is connected to a resist bottle 7 containing a photoresist solution 6. A liquid level sensor 8, a pump 9, a filter 10, a valve 11 in which an opening / closing valve 11a and a suck-back valve 11b are integrated are inserted in this resist supply pipe 5 in this order from the resist bottle 7 side.

In the resist coating apparatus having the above-described structure, the photoresist liquid 6 in the resist bottle 7 is sent out by a predetermined amount by the pump 9 while monitoring the running out of the liquid by the liquid level sensor 8, and the resist is passed through the filter 10 and the valve 11. The photoresist liquid 6 is supplied from the supply nozzle 4 to the semiconductor wafer 1 sucked and held on the spin chuck 2. Then, the photoresist liquid 6 is diffused by centrifugal force by rotating the semiconductor wafer 1 at a high speed by the spin chuck 2,
It is applied uniformly on the entire surface of the semiconductor wafer 1.

The filter 10 is for preventing particles generated in the pump 9 or the like from being supplied to the semiconductor wafer 1. Further, when the supply of the photoresist solution 6 is stopped by closing the opening / closing valve 11a, the suck back valve 11b prevents so-called dripping, for example, in which the photoresist solution 6 in the resist supply nozzle 4 falls on the surface of the semiconductor wafer 1. In order to prevent this, the photoresist liquid 6 is sucked from the inside of the resist supply nozzle 4 so as to flow backward.

[0007] Such a resist coating apparatus is, for example,
JP-A-61-4576, JP-A-60-144735, JP-A-62-119922, JP-A-63-299117, JP-A-60
-85524, JP-B-63-29406, and the like.

[0008]

However, in the above-mentioned conventional coating apparatus, since a pump, a filter, and the like are inserted into the supply pipe, it is necessary to provide a pipe connection mechanism, so-called fitting, between these devices and the supply pipe. There is. However, problems such as leakage of the liquid often occur at the fitting portion, and there is a problem that much labor and time are required to connect the fitting so as not to cause such a liquid leakage. Was.
Further, for example, in a resist coating apparatus or the like, there has been a problem that the photoresist liquid is soaked in steps, gaps, and the like formed inside the fitting portion, and the photoresist liquid is altered (for example, gelled).

There is also a coating apparatus which is configured to pump the coating liquid by using an inert gas such as a gas pressure of nitrogen gas without using a pump for sending the coating liquid. However, in such a coating apparatus, a photoresist is used. It is dangerous because the bottle etc. that contain the coating liquid such as liquid is always in a pressurized state.
In addition, there is a problem in that nitrogen gas or the like dissolves in the coating solution, causing bubbles to be generated, or the coating solution is deteriorated.

The present invention has been made in view of such a conventional situation, and can supply a predetermined amount of a coating liquid without using a pump or a pressurizing gas, thereby simplifying a supply pipe of the coating liquid. An object of the present invention is to provide a coating apparatus and a coating method capable of improving maintainability and preventing the pressurizing gas from dissolving into a coating liquid.

[0011]

In other words, a coating apparatus of the present invention supplies a predetermined amount of a coating liquid stored in a coating liquid storage section to an object to be coated by a predetermined amount from a coating liquid supply section via a supply pipe. And a mechanism for holding the coating liquid storage section at a higher position than the coating liquid supply section and for holding the coating liquid level in the coating liquid storage section at a predetermined height.
While supplying a predetermined amount of the coating liquid by the head,
The liquid level of the coating liquid in the cloth liquid storage section is maintained at the predetermined height.
A mechanism for vertically moving the coating liquid storage section so as to hold the coating liquid storage section . Further, the coating apparatus of claim 2 is
The coating liquid is a photoresist liquid.
You. Further, in the coating method according to the third aspect, a coating liquid
The predetermined application liquid stored in the storage section is supplied from the application liquid supply section.
In the coating method of supplying and applying, the coating liquid storage section
Where the liquid level of the coating liquid is higher than the coating liquid supply section.
Holding at a fixed height, and thereafter,
While supplying the coating liquid to the coating material,
The liquid level of the coating solution is maintained at the predetermined height.
Moving the coating liquid container up and down.
And

[0012]

According to the coating apparatus and the coating method of the present invention having the above-mentioned configuration, the coating liquid storage section is held at a higher position than the coating liquid supply section, and the coating liquid storage section is supplied while the coating liquid is supplied. as for holding the liquid surface of the coating liquid at a substantially constant height, it is moved up and down the coating liquid storage unit, you supply a coating liquid by drop.

Therefore, it is possible to supply a predetermined amount of the coating liquid without using a pump or a pressurizing gas.
Since the liquid level of the coating liquid in the coating liquid storage section is maintained at a substantially constant height, the supply amount of the coating liquid can be kept constant even when the amount of the coating liquid in the coating liquid storage section decreases.

This makes it possible to reduce the number of mechanisms such as a pump and a filter (which mainly captures particles generated by the pump), and to simplify the supply pipe of the coating liquid to improve the maintainability. That is, it is possible to reduce the number of fittings that are liable to cause liquid leakage and the like, and it is not necessary to perform maintenance of the pump, the filter, and the like, thereby improving the maintainability. Further, since the pressurizing gas is not used, the pressurizing gas does not dissolve into the coating solution, and the pressurizing gas does not break.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a resist coating apparatus for coating a photoresist liquid on a semiconductor wafer will be described below.
This will be described with reference to the drawings.

As shown in FIG. 1, the resist coating apparatus of this embodiment has a spin chuck configured to be able to hold a semiconductor wafer 20 to be coated by suction using a vacuum chuck or the like and rotate the semiconductor wafer 20 at a high speed. 21 are provided,
A cup 22 for preventing the photoresist liquid from scattering is provided so as to surround the periphery of the spin chuck 21.

A resist supply nozzle 23 is provided above the spin chuck 21. The resist supply nozzle 23 is connected to a resist supply pipe 24 composed of a flexible pipe that can be bent at least partially, for example, a resin pipe.
4 is connected to a resist bottle 26 containing a photoresist liquid 25. The resist bottle 26 is held upside down by the bottle holding mechanism 27 so that the height h of the liquid surface from the tip of the resist supply nozzle 23 becomes a predetermined height (for example, 500 to 1000 mm).

The bottle holding mechanism 27 is provided with a coil spring 28.
It is suspended from the support part 29 via the coil spring 28. Then, FIG. 2 (A), (B), (C)
As shown in FIG. 7, by appropriately selecting the spring constant of the coil spring 28, the photoresist liquid 25 in the resist bottle 26 decreases and the liquid level in the resist bottle 26 gradually decreases. The spring 28 is contracted, the resist bottle 26 is pulled up, and the liquid level in the resist bottle 26 is maintained at a substantially constant level. In addition, as described above, the resist supply pipe 24 is formed of a flexible pipe that can be bent at least partially, and as shown in FIG.
4a is provided. And this bent part 24a
Is deformed to allow the resist bottle 26 to move up and down.

In the resist supply pipe 24, only the valve 30 in which the open / close valve 30a and the suck-back valve 30b are integrated is inserted. The resist bottle 26 is provided with a gas introduction pipe 31 into which air or an inert gas (normal pressure) is introduced, and which allows the photoresist liquid 25 to be sent out by a head.

In the resist coating apparatus having the above structure, the semiconductor wafer 20 is loaded on the spin chuck 21 by a transfer arm (not shown) or the like.

Next, by opening the opening / closing valve 30a for a predetermined time, a predetermined amount of the photoresist liquid 25 in the resist bottle 26 is supplied to the semiconductor wafer 20 on the spin chuck 21 by a drop. The opening and closing valve 30a is closed and the suck back valve 30b is operated to suck the photoresist liquid 25 remaining in the resist supply nozzle 23 to prevent the photoresist liquid 25 from dripping onto the semiconductor wafer 20. The supply amount of the photoresist liquid 25 is adjusted by the opening time of the opening / closing valve 30a and the height of the resist bottle 26 (liquid level).

Thereafter, the photoresist liquid 25 is diffused by centrifugal force by rotating the semiconductor wafer 20 at a high speed by the spin chuck 21, and the photoresist liquid 25 is uniformly applied on the entire surface of the semiconductor wafer 20.

Then, the coated semiconductor wafer 20 is unloaded from above the spin chuck 21 by a transfer arm or the like (not shown).

By repeating such a procedure, a photoresist liquid 25 is applied to the semiconductor wafer 20 one after another. At this time, the coil spring 28 compensates for the resist bottle 2 by using a coil spring 28 so as to compensate for a decrease in the liquid level caused by a gradual decrease in the photoresist solution 25 in the resist bottle 26.
6 is pulled up, and the height h of the liquid level in the resist bottle 26 is kept almost constant, so that the supply amount of the photoresist liquid 25 due to the head can be always kept constant.

When the error in the supply amount of the photoresist liquid 25 was measured, the error was ± 6 when the photoresist liquid 25 was supplied in 2.0 cc increments by adjusting the liquid level as described above. %. This is the same error as the conventional resist coating apparatus using a pump as shown in FIG.

As described above, according to the resist coating apparatus of the present embodiment, the photoresist liquid 2 in the resist bottle 26
Even when the amount of 5 is reduced, the photoresist liquid 25 can be supplied by a predetermined amount without using a pump or a pressurizing gas.

Thus, it is possible to reduce the number of mechanisms such as a pump and a filter (which mainly captures particles generated by the pump), and to reduce the number of fittings that easily cause liquid leakage and the like. Also, maintenance of the filter and the like becomes unnecessary, and the maintenance performance can be improved. Further, since the pressurizing gas is not used, the pressurizing gas does not dissolve into the coating solution, and the pressurizing gas does not break. further,
By arranging the device in the vertical direction, the installation area can be reduced.

FIG. 3 shows the structure of a resist coating apparatus according to another embodiment, in which the same parts as those of the resist coating apparatus shown in FIG. 1 are denoted by the same reference numerals. In this embodiment, the resist bottle 26 is moved up and down by a driving mechanism 40 such as a motor or an air cylinder.
1 is provided. A liquid level sensor 42 for optically detecting the height of the liquid level in the resist bottle 26, for example.
The driving mechanism 40 is driven by the signal from the
1 is gradually raised to keep the liquid surface height h in the resist bottle 26 substantially constant, and the photoresist liquid 2
5 is always kept constant.

As in this embodiment, a signal from a liquid level sensor 42 or a sensor such as a weight sensor is fed back without using a coil spring or the like, and a motor, an air cylinder, etc. are driven to move the resist bottle 26 up and down. May be moved. In this case, the apparatus cost increases, but the liquid level can be more accurately controlled even when the photoresist liquid 25 having a different specific gravity is used. Further, the resist bottle 26 need not be held upside down.

In these embodiments, a resist coating apparatus for applying a photoresist liquid to a semiconductor wafer has been described. However, another apparatus for applying a coating liquid, for example, a developing liquid, or another coating object, for example, an LCD, may be used. The present invention can be similarly applied to a device for coating a substrate for use.

[0031]

As described above, the coating apparatus of the present invention
According to the coating method , the coating liquid can be supplied in a predetermined amount without using a pump or a gas for pressurizing, and the supply pipe of the coating liquid can be simplified to improve the maintainability, and the pressure can be increased. Dissolution of the gas into the coating liquid and the like can be prevented.

[Brief description of the drawings]

FIG. 1 is a view showing a schematic configuration of a resist coating apparatus according to an embodiment of the present invention.

FIG. 2 is a view for explaining the operation of the resist coating apparatus of FIG. 1;

FIG. 3 is a diagram showing a schematic configuration of a resist coating apparatus according to another embodiment.

FIG. 4 is a diagram showing a schematic configuration of a conventional resist coating apparatus.

[Explanation of symbols]

 Reference Signs List 20 semiconductor wafer 21 spin chuck 22 cup 23 resist supply nozzle 24 resist supply pipe 24a bent part 25 photoresist liquid 26 resist bottle 27 bottle holding mechanism 28 coil spring 29 support part 30 valve 30a open / close valve 30b suck back valve 31 gas introduction pipe

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Hikaru 1-170480 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/027

Claims (3)

(57) [Claims] A coating liquid supply unit configured to supply a predetermined amount of the coating liquid stored in the coating liquid storage unit to an object to be coated by a predetermined amount from a coating liquid supply unit via a supply pipe; While holding the coating liquid at a higher position than the coating liquid supply unit, the liquid level of the coating liquid in the coating liquid storage unit is
A mechanism for holding the coating liquid at a predetermined height and the coating liquid while supplying a predetermined amount of the coating liquid by a head
The liquid level of the coating liquid in the storage section is maintained at the predetermined height.
And a mechanism for vertically moving the coating liquid storage section . 2. The coating apparatus according to claim 1, wherein the coating liquid is a photoresist liquid. 3. An object to be coated is stored in a coating liquid storage section.
A predetermined coating liquid is supplied from the coating liquid supply section and applied.
In the cloth method, The coating liquid level in the coating liquid storage section is
Holding at a predetermined height higher than the supply unit; Thereafter, the coating liquid is supplied to the object to be coated by a drop.
The liquid level of the coating liquid in the coating liquid storage section
The coating liquid storage unit up and down so as to maintain the
And a coating method.