JPH02301138A - Apparatus and method for cleaning semiconductor wafer - Google Patents

Abstract

PURPOSE:To clean a wafer without occurrence of spot-like foreign materials and manufacture a highly reliable semiconductor device with high yield by a method wherein an exhaust pipe having a large diameter is placed on the bottom of a cleaning tank and an alcohol supply pipe is placed in the vicinity of the bottom respectively while pure water is discharged to be replaced with alcohol in a short time. CONSTITUTION:First a water supply valve 2 is opened to supply pure water to a cleaning tank 1 until the water overflows from the upper end into an exhaust tank 1a. Then a transfer basket 4 with a wafer 5 mounted is immersed and cleaned with water. After the specific resistance being 16MOMEGA.cm or larger (20 deg.C) is secured, the water supply valve 2 is closed and a drain valve 7 is opened to exhaust the pure water in the cleaning tank 1 immediately. As soon as drain of the pure water is completed, a supply valve 8 is opened to supply isopropyl alcohol solution. The speed for supplying isopropyl alcohol is specified so that it takes approximately 10 seconds for the solution to reach the upper part of the wafer 5. After the isopropyl alcohol solution completely having filled the cleaning tank 1 is assured, the transfer basket 4 is taken out. This method leaves no water drops on the surface of the wafer 5 and eliminates occurrence of spot-like foreign materials even through it takes time until the wafer is dried.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a semiconductor wafer cleaning apparatus and cleaning method for removing foreign matter from the surface of a semiconductor wafer.

(Prior Art) / With the miniaturization of semiconductor elements, patterns formed on the surface of semiconductor wafers have become denser and their steps have become larger. Along with this, cleaning and drying processes for semiconductor wafers have become important processes.

A conventional semiconductor wafer cleaning apparatus and its cleaning method will be explained with reference to FIG.

FIG. 2 is a side sectional view of a conventional cleaning device, in which a water supply valve 2 is installed near the bottom of the cleaning tank 1, which has a drainage groove 1a around the upper end.
A supply pipe 3 is provided.

The wafer 5 mounted on the transport basket 4 is washed in running pure water.

A cleaning method using the cleaning device configured in this way will be described.

First, open the water supply valve 2, and open the supply pipe 3. Supply pure water from
Next, the weber 5 is placed on the transport basket 4 and immersed in pure water with the water supply valve 2 left open. Continuously measure the specific resistance of the wastewater, e.g.
When a specified value of MΩ is reached or a specified time of, for example, 60 minutes has elapsed, the transport basket 4 is pulled up and dried.

(Problem to be Solved by the Invention) However, in the above cleaning apparatus and cleaning method, when the surface of the wafer 5 is hydrophobic, many water droplets adhere to the surface of the wafer 5 taken out from the cleaning tank 1. do. These water droplets tend to adhere to areas where there are large pattern steps formed on the surface of the wafer 5, and may not be completely removed even if a dehydration method using centrifugal force such as spin drying is employed. .

There is a problem in that the water droplets remaining on the surface of the wafer 5 react with the wafer 5 to form stain-like foreign matter, which causes defects in semiconductor devices. The conditions for the formation of stain-like foreign matter are determined by the time it takes for the water droplets to dry, and the longer it takes for the water droplets to dry, the greater the possibility of their occurrence.

The present invention solves the above problems and provides a cleaning device and a cleaning method that do not generate stain-like foreign matter.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides:
A large-diameter drain pipe and an alcohol supply pipe are installed near the bottom, and when cleaning with pure water is completed, the pure water can be drained and replaced with alcohol in a short time.

(Function) According to the above configuration, not only does the time that water droplets remain attached to the surface of the wafer become extremely short, but also the attached water droplets are dissolved in alcohol and disappear.

(Example) An example of the present invention will be described with reference to FIG. In the same figure, the difference between this embodiment and the conventional example shown in FIG. and that a supply pipe 9 equipped with a supply valve 8 for supplying alcohol is provided near the bottom. Since the rest is the same as the conventional example, the same components are given the same reference numerals and their explanations will be omitted.

A wafer cleaning method using the cleaning apparatus configured as described above will be described.

First, the water supply valve 2 is opened, and pure water is poured into the cleaning tank 1 and overflows from the upper end into the drain tank 1a. Next, the transport basket 4 carrying the wafer 5 is immersed and washed with water for about 20 minutes at a flow rate of about 1511/win. After confirming that the specific resistance is 16 MΩ·1 or more (at 20° C.), the water supply valve 2 is closed, the drain valve 7 is opened, and the pure water in the cleaning tank 1 is discharged all at once.

At the same time as the discharge of pure water is completed, the supply valve 8 is opened to supply isopropyl alcohol solution. The supply rate of isopropyl alcohol is such that the time required for it to reach the upper part of the wafer 5 is about 10 seconds. After confirming that the cleaning tank 1 is completely filled with the isopropyl alcohol solution, the transport basket 4 is taken out.

By this method, no water droplets remain on the surface of the wafer 5, and no stain-like foreign matter is generated even if it takes a long time to dry.

(Effects of the Invention) As described above, according to the present invention, it is possible to clean a wafer without generating stain-like foreign matter, and it is possible to manufacture semiconductor devices with high yield and high reliability.

[Brief explanation of the drawing]

1 and 2 are side sectional views of a semiconductor wafer cleaning apparatus showing an embodiment according to the present invention and a conventional example, respectively. 1...Cleaning tank, la...Drainage ditch, 2...Water supply valve, 3.9...Supply pipe, 4...Transport basket, 5...
wafer, 6...drain pipe, 7...drain valve, 8...
...Supply valve. Patent applicant: Matsushita Electronics Co., Ltd. Figure 1 Figure 2

Claims (2)

[Claims] (1) A cleaning tank with an overflow at the top, two supply ports each equipped with an on-off valve near its bottom, and a large-diameter drain port equipped with a drain valve located at the bottom. Semiconductor wafer cleaning equipment consisting of: (2) Supply pure water from one of the above supply ports, immerse the semiconductor wafer in the flowing water that overflows from the overflow at the top end, and open the drain valve when cleaning with pure water is finished. A method of cleaning semiconductor wafers in which the pure water is discharged all at once, and then an alcohol solution is supplied from another supply port to immerse the semiconductor wafer and then taken out.