JPH05267146A - Resist applicator - Google Patents

Abstract

PURPOSE:To make drying speed and time of resist on a wafer equal to prevent non-uniformity in application of the same size as a spin chuck. CONSTITUTION:A shape recognizer 10 recognizes the orientation flat of a wafer 8, aligns its orientation to a spin chuck 9 and sets it on the spin chuck 9. The wafer 8 is vacuum-chucked through the spin chuck 9, and resist is dripped on the center of the wafer while the wafer is stationary. After the resist is applied, the wafer 8 is rotated to form a thin resist film. Or while the wafer is being rotated, the resist is dripped onto the center of the wafer 8. Then the wafer 8 is rotated with different speed to form the thin resist film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist coating apparatus, and more particularly to a resist coating used for lithography.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view of a conventional resist coating apparatus. In FIG. 4, 1 is a wafer which is a semiconductor substrate. Reference numeral 2 is a spin chuck for mounting the wafer 1. Reference numeral 3 is a spin chuck shaft having one side attached to the lower portion of the spin chuck 2. Reference numeral 4 is a motor for rotating the wafer 1, the spin chuck 2, and the spin chuck shaft 3. Reference numeral 5 denotes a cup that collects the resist that is shaken off when the wafer 1, the spin chuck 2, and the spin chuck shaft 3 are rotated by the motor 4.

FIG. 5 is a plan view of a resist thin film formed by the conventional device shown in FIG. In FIG. 5, 6 indicates a region in contact with the wafer 1 and the spin chuck 2, and 7 indicates a region other than that. When the spin chuck 2 is in contact with the wafer 1 in the region 6 and the resist is spin-coated, the resist film thickness of the area contacted by the spin chuck 2 is different from the film thickness of the region 7 not contacted by the spin chuck 2. Such a state appears to the naked eye as a pattern as shown in FIG.

Regarding the resist coating apparatus as described above,
The resist coating process will be described below. The wafer 1 on which the resist is applied has the same temperature as the surroundings. Next, the wafer 1 is set on the spin chuck 2. Then, the wafer 1 is evacuated through the spin chuck 2. After that, resist is dropped. There are two methods for this dropping.

First, with the wafer 1 stationary,
A resist is dropped on the center of the wafer 1. After applying the resist, the wafer 1 is rotated to form a resist thin film.

Secondly, the resist is dropped on the central portion of the wafer 1 in a rotated state. After that, the wafer 1 is rotated at different rotation numbers to form a resist thin film.

[0007]

However, in the prior art device as described above, since the region 6 has the spin chuck, the wind does not hit the wafer 1 from below. for that reason,
The resist on the wafer 1 is not cooled. For it,
The area 7 has no spin chuck, and the wafer 1 is cooled by the wind from below. Due to the high thermal conductivity of silicon, the resist on it is also cooled.

Therefore, the regions 6 and 7 have a problem that the resist drying speed and the drying time are different from each other, and uneven coating having the same size as that of the spin chuck occurs.

In view of the above problems, the present invention provides a resist coating apparatus capable of preventing the coating unevenness of the same size as that of the spin chuck by making the drying speed and the drying time of the resist on the wafer 1 equal. ..

[0010]

In order to solve the above problems, a resist coating apparatus according to the present invention comprises a semiconductor substrate, a spin chuck having the same size and shape as the semiconductor substrate, and the semiconductor substrate. The spin chuck is provided with an installation unit that matches the shape of the spin chuck, and a spin chuck shaft attached to a lower portion of the spin chuck. When the semiconductor substrate and the spin chuck are rotated about the spin chuck shaft, The semiconductor substrate, the spin chuck, and the spin chuck shaft were prevented from being eccentric.

[0011]

The present invention uses the spin chuck having the same size and shape as the wafer according to the above-mentioned structure. Therefore, the spin chuck is provided under the wafer over the entire surface, and the wind does not hit the wafer from below. Therefore, the resist on the wafer is not cooled.

Therefore, the drying speed and the drying time of the resist on the entire surface of the wafer are equalized, and it is possible to prevent coating unevenness of the same size as the spin chuck.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A resist coating apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a resist coating apparatus according to an embodiment of the present invention. In the figure, 8 is a wafer which is a semiconductor substrate, and 9 is a spin chuck having the same size and shape as the wafer 8. Reference numeral 10 is a shape recognition device for the wafer 8. The shape recognition device 10 recognizes the orientation flat of the wafer 8 and aligns the orientation of the wafer 8 with the spin chuck 9. Reference numeral 11 denotes a spin chuck shaft having one side attached to the lower portion of the spin chuck 9. Spin chuck shaft 11
When the wafer 8 and the spin chuck 9 are rotated around, the eccentricity between the spin chuck 9 and the spin chuck shaft 11 is prevented. Reference numeral 12 is a motor that rotates the wafer 8, the spin chuck 9, and the spin chuck shaft 11. Reference numeral 13 is a cup for collecting the resist that is shaken off when the wafer 8, the spin chuck 9, and the spin chuck shaft 11 are rotated by the motor 12.

The resist coating process of the resist coating apparatus of this embodiment having the following structure will be described below.

The wafer 8 on which the resist is applied has the same temperature as the surroundings. The shape recognition device 10 recognizes the orientation flat of the wafer 8 and aligns the orientation of the wafer 8 with the spin chuck 9.

Next, the wafer 8 is set on the spin chuck 9. Then, the wafer 8 is evacuated through the spin chuck 9.

After that, resist is dropped. There are two methods for this dropping. First, the resist is dropped onto the central portion of the wafer 8 while the wafer 8 is stationary. After applying the resist, the wafer 8 is rotated to form a resist thin film.

Second, the resist is dropped on the central portion of the wafer 8 in a rotated state. After that, the wafer 8 is rotated at different rotation numbers to form a resist thin film.

The mechanism until the resist thin film is formed after the resist is dropped will be described in detail. Figure 5
FIG. 5 is a plan view of a resist thin film formed by the prior art device shown in FIG. In FIG. 5, 6 indicates a region in contact with the wafer 1 and the spin chuck 2, and 7 indicates a region other than that.

In the prior art apparatus of FIG. 4, since the area 6 has the spin chuck 2, the wind does not hit the wafer 1 from below. Therefore, the resist on the wafer 1 is not cooled. On the other hand, the region 7 does not have the spin chuck 2, and the wafer 1 is cooled by the wind from below. Due to the high thermal conductivity of silicon, the resist on it is also cooled.

Therefore, there is a difference in the drying speed and the drying time of the resist between the area 6 and the area 7, and uneven coating having the same size as that of the spin chuck 2 occurs.

Further, the state where uneven coating is generated will be described. 2 and 3 are cross-sectional views of resist thin films formed by the prior art device of FIG. In FIG. 2, 14
Is an area in contact with the wafer 1 and the spin chuck 2, 15
Indicates the other area. In FIG. 3, 16 indicates a region in contact with the wafer 1 and the spin chuck 2, and 17 indicates a region other than that.

In FIG. 2, the film thickness of the region 15 is in a state of becoming thinner toward the outside. In addition, in FIG.
The film thickness of is thicker toward the outside. This is determined by the type of resist and the change in the rotation speed of the wafer 1.

However, when the spin chuck 9 having the same size and shape as the wafer 8 is used as in the embodiment shown in FIG. 1, since the spin chuck 9 is under the entire surface of the wafer 8, the wind blows from below. Does not hit the wafer 8. Therefore, the resist on the wafer 8 is not cooled.

Accordingly, the drying speed and the drying time of the resist on the entire surface of the wafer 8 become equal, and it is possible to prevent uneven coating of the same size as the spin chuck 2.

On the other hand, the case where an organic resist is used is adapted to the above mechanism by which the effect of this apparatus can be obtained. Organic resists are highly volatile. Therefore, area 6 and area 7
The difference between the resist drying speed and the drying time is small.

However, the water-soluble resist has lower volatility than the organic resist. In the case of a water-soluble resist, it takes a long time to form a resist thin film. Therefore, the difference in the resist drying speed and the drying time between the area 6 and the area 7 is large.

Therefore, the water-soluble resist can prevent coating unevenness by using the spin chuck 8 having the same size and shape as the wafer than the organic resist.

Further, in the prior art device of FIG. 4, when the surroundings are in a windless state, the region 7 is not strongly exposed to the wind from below.
Therefore, the difference in the resist drying speed and the drying time between the area 6 and the area 7 becomes small. However, in this state, it is not possible to prevent the particles from being wound up due to the rotation of the wafer 1. Particles adhere to the wafer 1 to cause striation.

Therefore, by using the spin chuck 9 having the same size and shape as the wafer 8 and further applying downflow to the periphery of the apparatus, striation (change in film thickness in a minute region) and uneven coating can be eliminated at the same time. be able to.

Further, in order to prevent the coating unevenness of the same size as the spin chuck, the present invention does not utilize the change in the rotation speed of the wafer 8. Therefore, it is possible to easily find the optimum coating conditions for obtaining the resist type and the desired film thickness, and it is possible to form a uniform resist thin film with good reproducibility by the coating performed under the conditions. Wafer 8
Can be used.

Although the foregoing invention has been described in detail by way of illustration and example method for clarity of understanding, it is obvious that certain changes and modifications may be made within the scope of the appended claims.

[0034]

As described above, the present invention can eliminate striations and coating unevenness at the same time by using a spin chuck of the same size as a wafer and further applying downflow in the coater. Further, in order to prevent coating unevenness of the same size as the spin chuck, the present invention can easily find the optimum coating conditions for obtaining the resist type and the desired film thickness, and the coating performed under the conditions. Then, a uniform resist thin film can be formed with good reproducibility.

[Brief description of drawings]

FIG. 1 is a sectional view of a resist coating apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a resist thin film formed by a resist device.

FIG. 3 is a sectional view of a resist thin film formed by a resist device.

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

FIG. 5 is a plan view of a resist thin film formed by a conventional resist coating apparatus.

[Explanation of symbols]

 8 Wafer 9 Spin Chuck 10 Shape Recognition Device 11 Spin Chuck Shaft 12 Motor 13 Cup

Claims (2)

[Claims] 1. A semiconductor substrate, a spin chuck having the same size and the same shape as the semiconductor substrate, a mounting means for matching the shapes of the semiconductor substrate and the spin chuck, and attached to a lower portion of the spin chuck. The spin chuck shaft, a motor for rotating the semiconductor substrate, the spin chuck shaft, and the spin chuck shaft, and a resist shaken off during rotation of the semiconductor substrate, the spin chuck shaft, and the spin chuck shaft. A resist coating device equipped with a collection cup. 2. The resist coating apparatus according to claim 1, wherein the resist is a water-soluble resist.