JPH0620935A - Resist coating device - Google Patents

Abstract

PURPOSE:To reduce the number of dusts on a rear surface of a wafer in the step of coating with resist in the case of miniaturizing a semiconductor product. CONSTITUTION:A straightening plate 15a is raised in height to the back of a wafer 1, and a position of a back rinsing nozzle 3 is also moved to the back of the wafer 1. Thus, the number of dusts on the rear surface of the wafer 1 can be reduced by about 900 pieces, and its fraction defective of next step can be decreased.

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 used for semiconductor manufacturing.

[0002]

2. Description of the Related Art In a conventional resist coating apparatus, a state in which a wafer 1 is adsorbed by a spin chuck 2 and rotating is shown in FIG. 2 as a sectional view, and a resist coating procedure is shown in FIG.

The wafer 1 is attracted to the spin chuck 2,
After the resist solution is dropped and applied around the center of the upper surface of the wafer 1, the wafer is rotated and the resist solution is spread over the entire surface of the wafer 1 by centrifugal force, and the excess resist solution is shaken off.

The scattered resist 6 is received by the cup 4 and discharged from the discharge port 7. Also, the clean downflowed air hits the opening of the cup 4. The air is also discharged from the discharge port 7 together with the scattered resist 6 hitting the cup 4 and becoming smaller and atomized.

By the way, the spin chuck 2 is mounted on the wafer 1.
When it comes into contact with, there is a chance that foreign matters and dirt that have fallen and adhered onto the spin chuck 2 will adhere to the back surface of the wafer 1, so the diameter of the spin chuck 2 is made as small as possible. Therefore, as shown in FIG. 2, the peripheral portion of the back surface of the wafer 1 is exposed from the spin chuck 2.

In order to prevent the above-mentioned atomized resist 6 from adhering to the exposed portion, the air flow is regulated by the straightening plate 5 to prevent turbulence.

Then, the flow rectifying plate 5 minimizes the gap with the wafer 1 at the outer end portion of the wafer 1 so that the air flow is reduced.
It has a structure that covers the entire back surface as well as preventing it from flowing into the back surface.

However, the rotation of the wafer 1 is fast, and the speed of the resist 6 that scatters is also fast, so that the turbulence of the air flow is difficult to avoid, and as shown in FIG. Further, an airflow that enters the back surface of the wafer 1 is generated, so that the resist 6 is not easily attached to the back surface of the wafer 1.

Therefore, while the wafer 1 is continuously rotated, the rinse liquid is jetted from the back rinse nozzle 3 for cleaning.

[0010]

As the miniaturization of semiconductor products progresses, it is necessary to reduce the number of dusts on the back surface of the wafer. However, with the conventional shape of the straightening plate 5 and the position of the back rinse nozzle 3, the back surface of the wafer is reduced. There was a drawback that a lot of dust and dirt remained.

That is, if the adhesion amount is too large, the cleaning cannot be completed, and since the wafer 1 is rotating, the rinse liquid flows outward due to the centrifugal force, so that the rinse liquid on the center side of the back rinse nozzle 3 is located. The cleaning effect is low and dust and dirt are likely to remain, resulting in problems in the post process.

[0012] Therefore, an object of the present invention is to provide an apparatus in which dirt and dust are less attached to the back surface.

[0013]

A resist coating apparatus according to the present invention comprises a spin chuck for adsorbing and rotating a wafer,
A cover for receiving the scattering coating solution, and a cover for covering a portion exposed from the spin chuck on the back surface side of the wafer in close proximity, and the adjacent portion is at least 10 mm or more from the outer edge of the wafer, A back rinse nozzle for cleaning the back surface of the wafer is provided at a position close to the center within a range where the jetted liquid does not directly contact the outer peripheral edge of the spin chuck.

Further, the distance between the lower surface of the wafer and the upper surface of the current plate is 0.5 to 1.0 mm.

[0015]

According to the above construction, when the resist is applied by the cover close to the back surface of the wafer, the resist can be prevented from wrapping around the back surface of the wafer, and the slightly soiled resist is located at the position where the back rinse nozzle is close to the center. Since it is located at, the cleaning effect is high and it is almost washed away.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the left half of a state in which a wafer 1 according to an embodiment of the present invention is attracted by a spin chuck 2 and is being rotated. In the figure, 1 is a wafer, 2 is a spin chuck, 3 is a back rinse nozzle, 4 is a cup, 15 is a straightening plate, and 6 is a resist.

The wafer 1 is attracted to the spin chuck 2, the resist is applied on the wafer 1, and the wafer 1 is rotated at an arbitrary number of rotations for a time, whereby the resist is scattered and hits the cup 4, and the current plate 15 is contacted. I try to wrap around the backside of the wafer. In the conventional rectifying plate (reference numeral 5 in FIG. 2), the proximity portion between the wafer and the rectifying plate was not visible, and the resist 6 was easy to wrap around. About 20 in length
By increasing the length to mm, the wraparound of the resist 6 can be suppressed, and the cleaning effect can be enhanced by moving the position of the back rinse nozzle 3 behind the wafer.

The proximity portion 15a of the current plate 15 serving as a cover for covering the back surface of the wafer 1 to the wafer 1 is designed to have a gap of 0.5 mm from the wafer 1. Since the spin chuck 2 vacuum-adsorbed 1 to the wafer 1, the surface of the wafer 1 was concave and the warp was about 1 mm.

Further, the longer the length of the proximity portion 15a is, the more effective it is.

If the distance between the lower surface of the wafer 1 and the upper surface of the rectifying plate 5 is less than 0.5 mm, there is a risk of contact with the rectifying plate 5 due to the back surface condition of the wafer 1 or warpage.
If it exceeds 0 mm, the adhesion of the resist to the lower surface of the wafer 1 is recognized.

[0022]

As described above, according to the present invention, by increasing the height of the current plate to the back and moving the back rinse nozzle position to the back of the wafer, it is possible to reduce the number of dust on the back surface of the wafer by about 9,000. In addition, it is possible to reduce the defect rate that occurs in the next process.

[Brief description of drawings]

FIG. 1 is a sectional view showing a state in which a wafer of a resist coating apparatus of the present invention is rotating.

FIG. 2 is a sectional view of a conventional resist coating apparatus in which a wafer is rotating.

FIG. 3 Flowchart of resist coating

[Explanation of symbols]

 1 Wafer 2 Spin chuck 3 Back rinse nozzle 4 Cup 15 Rectifier plate 15a Proximity part of rectifier plate 6 Resist

Claims (2)

[Claims] 1. A resist coating apparatus having a spin chuck that attracts and rotates a wafer, and a cup that receives a coating solution that scatters, wherein the spin chuck has a smaller diameter than the wafer. A cover is provided to cover a portion of the back surface exposed from the spin chuck in close proximity, and the adjacent portion is at least 10 mm or more from the outer edge of the wafer, and is centered within a range in which the outer peripheral edge of the spin chuck does not directly hit the jetted liquid. And a back rinse nozzle for cleaning the back surface of the wafer at a position close to. 2. The distance between the lower surface of the wafer and the upper surface of the adjacent portion of the cover is. The resist coating apparatus according to claim 1, which has a thickness of 0.5 to 1.0 mm.