KR19990005888A - Wafer cleaning method - Google Patents

Abstract

1. Technical field to which the invention described in the claims belongs

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer cleaning method, and more particularly, to a semiconductor device cleaning method using a single bath type.

2. Technical problem that the invention tries to solve

When the wafer is cleaned, the cleaning solution residues on the surface of the wafer contacted with the cleaning bath are prevented from deteriorating the electrical characteristics and the yield of the device.

3. Summary of the solution of the invention

The washing process and the drying process are repeated twice to remove the residue of the washing solution.

4. Important uses of the invention

It is applied to the wafer cleaning process in the semiconductor device manufacturing process.

Description

Wafer cleaning method

The present invention relates to a wafer cleaning method, and more particularly, to a wafer cleaning method using a single bath type.

In general, the multi-bath type wet cleaning equipment used for the cleaning process in the semiconductor manufacturing process occupies an area in the clean room because the size of the equipment continues to increase as the wafer size changes to large diameter. The problem of increasing productivity also decreases. Therefore, in order to solve the problems of the multiple cleaning tank type wet cleaning equipment, a single cleaning tank type wet cleaning equipment has been developed. The single cleaning tank type wet cleaning equipment can carry out all cleaning and drying processes possible in the existing equipment at the same time by using only one closed cleaning bath, and various types of cleaning liquids can be easily combined. It is configured to.

The conventional wet cleaning process using a single cleaning type sulfuric acid (H ₂ SO ₄ ) is as follows.

In the first step, the sulfuric acid cleaning process is a process for removing particles and organics. After loading the wafer into the cleaning tank, ozone (O ₃ ) is concentrated in sulfuric acid, heat treatment, and then circulated inside the cleaning tank. Clean the wafer surface.

After the second step, the sulfuric acid cleaning process is completed, sulfuric acid in the cleaning tank is transferred to a sulfuric acid storage tank using N ₂ gas, and overflowed using deionized water. At the same time, an ultrasonic cleaning device is used to clean the remaining cleaning liquid on the inner surface of the cleaning tank and the wafer surface.

In the third step, the wafer drying process is a process of drying the wafer by introducing vapor of isopropyl alcohol hole into the cleaning tank while slowly flowing out pure water in the cleaning tank.

At this time, the cleaning tank used in the wet cleaning equipment of the single cleaning tank type can be completely sealed using an O-ring up and down to prevent leakage of the cleaning liquid. In addition, the cleaning tank generally uses a Teflon-based material because a material capable of maintaining cleanliness without being damaged by various cleaning solutions is used. Teflon-based materials, such porous materials, have many micro holes. In addition, the wafer support in the cleaning bath contacting the wafer during wafer loading and unloading generates fine cracks due to surface damage caused by collision. At this time, during the wafer cleaning, the cleaning solution such as H ₂ SO ₄ having a small contact angle with respect to the Teflon material penetrates into the micro holes or the micro cracks. The infiltrated cleaning liquid is removed in a continuous cleaning process using deionized water, but is not completely removed at the part supporting the wafer in the cleaning tank. Thus, the remaining cleaning solution is eluted to the isopropyl alcohol hole solution in the isopropyl alcohol hole drying process and remains as a cleaning solution residue on the surface of the wafer in contact with the cleaning bath, thereby lowering the electrical characteristics and yield of the device.

Accordingly, an object of the present invention is to provide a method for cleaning a semiconductor device capable of effectively removing the cleaning solution remaining on the wafer surface.

A first embodiment according to the present invention for achieving the above object is a first step of cleaning the wafer surface with a sulfuric acid solution of the wafer, and using an ultrasonic cleaning device while cleaning the wafer surface with pure water A second step of cleaning the remaining cleaning liquid on the inner surface of the cleaning tank and on the surface of the wafer; And a fourth step of cleaning the wafer surface using pure water supplied with sound waves while simultaneously rotating the wafer at a high speed.

The second embodiment according to the present invention for achieving the above object is a first step of cleaning the wafer surface with a sulfuric acid solution of the wafer, and using an ultrasonic cleaning device at the same time to clean the wafer surface using pure water A second step of first cleaning the remaining cleaning liquid on the inner surface of the cleaning tank and the surface of the wafer; a third step of first drying the wafer using a drying gas after partially discharging the pure water in the cleaning tank; And a fourth step of secondly cleaning the wafer surface using ultrasonic waves, and a fifth step of secondly drying the wafer by introducing the dry matter into the cleaning tank.

The present invention is described in detail as follows.

The sulfuric acid (H ₂ SO ₄ ) cleaning process of the single cleaning tank type according to the first embodiment of the present invention is as follows.

In the first step, after loading the wafer into the cleaning bath, ozone (O ₃ ) is concentrated in sulfuric acid so as to remove particles and organics from the wafer surface and heat-treated at 80 to 100 ° C., and then into the cleaning bath for 5 to 10 minutes. The wafer is circulated to clean the wafer.

In the second step, sulfuric acid in the cleaning tank is transferred to a sulfuric acid storage tank using N ₂ gas and then overflowed with pure water. At the same time, an ultrasonic cleaning device is used to clean the remaining cleaning liquid on the inner surface of the cleaning tank and the wafer surface. The washing time is performed at 16 kPa or more for 5 minutes or more in consideration of the resistance of the pure water fluorinated into the washing tank.

In the third step, the pure water in the washing tank is maintained at a temperature of 45 to 65 ° C, and then the pure water is partially discharged. Thereafter, vapor of the isopropyl alcohol hole is introduced into the cleaning tank to dry the wafer.

Step 4, using a Dionized water-Sonic scrubber equipment to rotate at a high speed of 1000 to 6000 RPM to remove the residue of the cleaning solution, and removes pure water supplied with D-sound by washing the front and back of the wafer do.

The sulfuric acid (H ₂ SO ₄ ) cleaning process of the single cleaning tank type according to the second embodiment of the present invention is as follows.

In the first step, after loading the wafer into the cleaning bath, ozone (O ₃ ) is concentrated in sulfuric acid to remove particulates and organics on the surface of the wafer, followed by heat treatment at 80 to 100 ° C., and then circulated inside the cleaning bath for 5 to 10 minutes. Clean.

In the second step, sulfuric acid in the cleaning tank is transferred to a sulfuric acid storage tank using N ₂ gas and then overflowed with pure water. At the same time, the residual cleaning liquid on the inner surface of the cleaning tank and on the wafer surface is first cleaned using an ultrasonic cleaning device. The washing time is performed at 16 kPa or more for 5 minutes or more in consideration of the resistance of pure water in the washing tank.

In the third step, the pure water in the washing tank is maintained at a temperature of 45 to 65 ° C, and then the pure water is partially discharged. Thereafter, vapor of the isopropyl alcohol hole is introduced into the cleaning tank to dry the wafer first.

In a fourth step, the wafer is second cleaned using ultrasonic waves and pure water.

In the fifth step, the pure water in the washing tank is maintained at a temperature of 45 to 65 ° C, and then the pure water is partially discharged. Thereafter, vapor of the isopropyl alcohol hole is introduced into the cleaning bath to dry the wafer secondly.

As described above, since the residual cleaning liquid of the wafer is effectively removed, the reliability and electrical characteristics of the semiconductor device may be improved.

Claims (9)

A first step of cleaning the wafer surface with a sulfuric acid solution; and a second step of cleaning the wafer surface with pure water and at the same time using an ultrasonic cleaning device to clean the remaining cleaning solution on the inner surface of the cleaning tank and the wafer surface And a third step of drying the wafer using a dry gas after partially discharging the pure water in the cleaning tank, and using pure water supplied with sound waves while rotating the wafer at a high speed so that the residue of the cleaning liquid is removed. And a fourth step of cleaning the wafer surface. The wafer cleaning method according to claim 1, wherein after the ozone is added to the sulfuric acid solution in the first step, the sulfuric acid solution is heat-treated at 80 to 100 ° C. for a cleaning process for 5 to 10 minutes. The method of claim 1, wherein in the third step, the dry gas is isopropyl alcohol hole. The method of claim 1, wherein in the third step, the temperature of the pure water is maintained at 45 to 65 ℃. The method of claim 1, wherein in the fourth step, the rotation speed of the wafer is 1000 to 6000 RPM. A first step of cleaning the wafer surface with a sulfuric acid solution, and a first step of cleaning the wafer surface using pure water and the first cleaning of the remaining cleaning liquid on the inner surface of the cleaning tank and the wafer surface using an ultrasonic cleaning device Step 2, a third step of first drying the wafer using a dry gas after the partial flow of the pure water in the cleaning tank, and a fourth step of secondary cleaning the wafer surface using the pure water and ultrasonic waves And a fifth step of injecting the dry matter into a cleaning tank to dry the wafer secondarily. The wafer cleaning method according to claim 6, wherein in the first step, the ozone is added to the sulfuric acid solution, and the sulfuric acid solution is heat treated at 80 to 100 ° C for 5 to 10 minutes. 7. The method of claim 6, wherein in the third and fifth steps, the dry gas is isopropyl alcohol hole. 7. The method of claim 6, wherein in the third step, the temperature of the pure water is maintained at 45 to 65 ° C.