JPS58123A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the exfoliation of a photo-resist in post-processes by immersing a wafer in an acidic solution just before the photo-resist is applied onto the wafer. CONSTITUTION:An oxide film 2 is formed onto the surface of the wafer 1. The wafer 1 is immersed in the mixed liquid of ammonia and hydrogen peroxide, washed by water and dried. The wafer is immersed in the acidic aqueous solution, washed by water and dried. The photo-resist 3 is applied. The wafer is developed through selective exposure. Accordingly, the exfoliation of the photo- resist can be prevented in the post-photo-resist processes.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a semiconductor device, and particularly relates to a process of coating a photosensitive resin (hereinafter referred to as photoresist) in a manufacturing process of a semiconductor device.

For the purpose of selective diffusion of semiconductor devices, a developed film on a semiconductor substrate (hereinafter referred to as a wafer) formed by thermal oxidation or the like is selectively etched by patterning a 7-photoresist. This photoresist pattern ninder press is very fine, so if foreign matter such as dust from the surrounding work environment is mixed in, it will be in a poor condition and it will often be impossible to achieve the desired pattern. Cleaning of previous wafer is required. A wet method is mainly used to clean sea urchins, and in many cases, the wafer is immersed for several minutes in a mixture of hydrogen peroxide and aqueous ammonia heated to about 60°C. However, if the photoresist is applied directly after cleaning, the photoresist will peel off or peel off during development. This phenomenon is considered to be due to the fact that the surface of the wafer is basic, which weakens the adhesion strength between the 7 photoresist and the wafer. Traditionally, after cleaning the wafer, a method to solve this problem.

In order to change the surface condition of the wafer, a heating method has been used, but heating at 500 to 600°C is not very effective and requires heating at 1000°C or higher. This method has drawbacks such as thermal stress being applied to the wafer, the work being complicated, and the wafer becoming stained again.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor device that eliminates the above-mentioned drawbacks of the conventional manufacturing method.

A feature of the present invention is a method of manufacturing a semiconductor device in which after cleaning the wafer, the wafer is not heated, but is immersed in an acidic aqueous solution, and then a 7OF resist is applied.

According to this method, peeling of the photoresist does not occur. Furthermore, if an automatic wafer cleaning machine is used and a tank of this acid is installed next to the wafer cleaning tank, the process will be carried out automatically and no extra effort will be required.

Next, embodiments of the present invention will be described based on the drawings.

First, as in the first ml, an oxide film 2 is formed on the surface of a semiconductor substrate (wafer) 1 by thermal oxidation. Next, in order to clean the wafer, it is immersed for several minutes in a mixture of ammonia and hydrogen peroxide heated to about 60° C., then washed with water and dried. After that, it is immersed for several tens of seconds in an acidic aqueous solution (concentrated about 5% hydrochloric acid, nitric acid, sulfuric acid, heptanoic acid, etc.), then washed with water and dried. Next, apply 7 Otoresist using a spinner, and the result will be as shown in Figure 2. Next, by selective exposure and development, a good patterning as shown in FIG. 3 is obtained. If the above-mentioned immersion treatment in the acidic aqueous solution is not performed, the adhesion of 7 Otoresist will be weak.
It's not good to end up like the one in Figure 4.

When the wafer is wet-cleaned as described above, if acid treatment is performed next, peeling of the photoresist can be prevented in the subsequent photoresist step.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an oxide film formed on the surface of a semiconductor substrate by thermal oxidation, Fig. 2 is a cross-sectional view showing a state in which 7 photoresist is coated on the oxide film, and Fig. 3 is a cross-sectional view showing a state in which the oxide film is coated on the oxide film. A sectional view showing a developed state, and FIG. 4 is a sectional view showing an abnormal state. In the figure, 1: semiconductor substrate, 2: oxide film, 3: photoresist, 4: normally patterned photoresist, 5: abnormally patterned photoresist. . Agent: Susumu Uchihara, patent attorney Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A semiconductor device manufacturing method including a process of wet cleaning a semiconductor substrate and applying a photosensitive W resin, characterized by immersing the substrate in an acidic solution immediately before applying the photosensitive resin to the semiconductor substrate. A method for manufacturing a semiconductor device.