JPS6386433A - Photoresist coating method - Google Patents

Abstract

PURPOSE:To prevent the generation of defects in a photoresist by a method wherein, when the photoresist is rotary painted on a semiconductor substrate and the photoresist on the substrate edge is removed, a guide ring smaller in size than the substrate is moved close to the substrate, and high pressure gas is blown into said guide ring. CONSTITUTION:After the dust on the surface of a semiconductor substrate 11 has been cleaned by rotating the substrate at high speed, a photoresist 12 is dripped thereon. Then, the semiconductor substrate 11 is rotated at the revolution number for the period with which the desired film thickness can be obtained, and a photoresist film is formed on the semiconductor substrate. Subsequently, a guide ring 13, having the diameter smaller by 3 mm than the semiconductor substrate 11, is brought to the point aparted from the substrate by 1 mm, the substrate 11 is rotated while N2 gas is being fed into the guide ring 13, and resist thinner 14 is blown against the edge of the substrate. Besides, the substrate is rotated for drying and removal of the atmosphere of resist thinner. As a result, the intrusion of the splash and the atmosphere of said thinner into the center part of the substrate can be prevented, and the defectless photoresist can be formed.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a photoresist coating method.

(Prior art) Lithography technology using photoresist is an essential technology for manufacturing semiconductor integrated circuits, and in recent years, 1u
In addition to M, submicron ring fee technology is also being put into practical use. Photoresist is used as a mask during the above-mentioned fine processing, but if it is not removed after processing, it will cause contamination in subsequent steps. Further, photoresist is usually formed on a semiconductor substrate by a spin coating method, but if the photoresist spreads onto the back surface of the semiconductor substrate at this time, it will contaminate various devices in subsequent steps.

Therefore, a method is used to remove the resist from the etched portions of the semiconductor substrate. Usually, the resist from the etched portions of the substrate is removed by spraying thinner, which serves as a solvent for the resist, toward the etched area of the substrate while rotating the semiconductor substrate. However, it is difficult to optimize the number of rotations of the substrate and the amount of thinner sprayed, and if optimization is insufficient, thinner droplets and the atmosphere may cause pins to reach the photoresist in the center of the substrate. Generate defects such as holes.

(Problems to be Solved by the Invention) As described above, in the conventional resist removal method for etching a substrate, there is a concern about defects at the center of the substrate. This is thought to be due to the droplets that splash when the thinner is sprayed onto the rotating board and the residual atmosphere. Therefore, a guide ring as shown in Figure 1 is brought close to the substrate, and while blowing a non-reactive high pressure gas there, the resist for etching the substrate is removed.
can be prevented from occurring.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a method in which a guide ring having a diameter smaller than the substrate by a desired amount is brought closer to the substrate when a photoresist is spin coated on a semiconductor substrate and the photoresist is removed from etching of the substrate. , by blowing high pressure gas into this guide ring,
It is characterized by preventing the occurrence of defects in the photoresist at the center of the substrate.

(Function) According to the present invention, it is possible to prevent thinner droplets and atmosphere for removing the photoresist from etching the substrate from entering the center of the substrate, and to form a defect-free photoresist from which the etched portions of the substrate have been removed. be able to.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
4 to 4 show specific examples of a photoresist coating formation method using the substrate edge resist removal method of the present invention.

First, the semiconductor substrate 11 is rotated at high speed to clean dust on the surface of the substrate, and then a photoresist 12 is dropped. Then 0.8sec at 500 rpm, 600 rpm
Rotate for 0.8 seconds at 4000r to obtain the desired film thickness.
pm for 20 seconds to form a photoresist on the semiconductor substrate (FIG. 1).

Next, the guide ring 13, which is smaller in diameter than the semiconductor substrate 11 by 3111 m, is brought closer to the substrate 11 at a distance of 1 m (second
figure).

Furthermore, the substrate 11 is rotated at 400 rpm while blowing N2 gas into the guide ring 13, and resist thinner 14 is sprayed for 10 seconds toward the etched area of the substrate (FIG. 3).

Furthermore, 4,000 yen was added to remove the resist thinner atmosphere.
Dry and rotate for 20 seconds using RP Maro (Figure 4).

〔Effect of the invention〕

GaAs I was prototyped using the photoresist coating method using the substrate edge resist removal method according to the present invention.
By reducing dust and defects according to the present invention, the Yelld of C was improved from 60% to 80%.

FIG.

]1...Semiconductor substrate 12...Photoresist 13...Guide ring 14...Resist thinner Agent: Patent Attorney Noriyuki Chika Same Bamboo Flower Kikuo Figure 1 Figure 2 s3 diagram I! Figure 4

Claims (1)

[Claims] When spin-coating photoresist onto a semiconductor substrate, the photoresist is dropped and spin-coated for a certain period of time at a desired number of rotations, then a guide ring with a smaller diameter than the semiconductor substrate is brought closer to the semiconductor substrate by a desired amount, and the inside of this guide ring is A photoresist coating method characterized by flowing resist thinner on the outside of a guide ring while blowing high-pressure gas to remove resist on the edge or back surface of a semiconductor substrate.