KR20020001386A - Method for drying a wafer - Google Patents

Abstract

PURPOSE: A method for drying a wafer is provided to prevent a wafer from being damaged by high speed rotation or high heat and to reduce defects caused by a damaged wafer, by easily vaporizing cleaning liquid remaining on the surface of the wafer at a room temperature and a low pressure. CONSTITUTION: A wafer(4) after a cleaning process is loaded to the inside of a bath(1) maintaining a constant temperature, and the temperature inside the bath is controlled. The pressure inside the bath is controlled to vaporize cleaning liquid remaining on the surface of the wafer.

Description

Wafer Drying Method {Method for drying a wafer}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer drying method, and more particularly, to a wafer drying method capable of preventing damage and damage to a wafer.

Generally, in the semiconductor device manufacturing process, before forming a predetermined layer on a wafer or after performing an etching process, cleaning is performed to remove contaminants such as natural oxide film, organic matter, and inorganic matter (metallic impurities) remaining on the surface of the wafer. Carry out the process. After the cleaning is completed, a drying step for removing the cleaning liquid remaining on the surface of the wafer is performed.

Conventionally, a spin dryer or a chemical vapor dryer was used to remove the cleaning liquid remaining on the surface of the cleaned wafer.

The rotary dryer rotates the wafer at a high speed at room temperature to remove the cleaning liquid present on the surface of the wafer by centrifugal force, and the chemical vapor dryer generates chemical vapor at a high temperature (˜200 ° C.), thereby presenting it on the surface of the wafer. Allow the cleaning liquid to be removed.

However, when the tumble dryer is used, the wafer is rotated at a high speed, and thus the wafer is broken, and the wafer is attached to the rotating plate, thereby causing defects due to particle adhesion. In addition, as the size of the wafer increases, the size of the dryer also increases.

On the other hand, the use of a chemical vapor dryer eliminates the generation of particles. However, since drying occurs at a high temperature, thermal damage of the wafer due to high heat is concerned, and a fire may occur due to the use of chemical vapor.

Accordingly, an object of the present invention is to provide a wafer drying method that can solve the above disadvantages by allowing the cleaning liquid remaining on the surface of the wafer to be easily vaporized at room temperature and low pressure.

1 is a block diagram of a drying apparatus used in the present invention.

<Explanation of symbols for the main parts of the drawings>

1: thermostat 2: exhaust vent

3: vacuum pump 4: wafer

In the wafer drying method according to the present invention, after the cleaned wafer is loaded into the thermostat, the temperature of the thermostat is adjusted, and the pressure of the thermostat is adjusted so that the cleaning liquid remaining on the surface of the wafer is vaporized. It is made, the temperature inside the thermostat is adjusted to 10 to 30 ℃, the pressure is adjusted to 20 to 80mmHg.

Next, the present invention will be described in detail with reference to the accompanying drawings.

In the case of a single substance, the boiling point of the liquid has an intrinsic value at constant pressure conditions, but as the pressure decreases, the vaporization temperature is lowered. This is represented by the following formula (1).

pV = nRT

Where p is pressure, V is volume, n is Mole number, R is gas constant and T is temperature.

As can be seen from the above ideal gas equation, since the boiling point is lowered when the pressure is reduced, vaporization of the liquid occurs at a lower temperature. Therefore, using this principle, the liquid can be dried even at low temperatures.

The present invention uses this principle to remove the cleaning liquid remaining on the surface of the wafer.

To this end, a drying apparatus constructed as shown in FIG. 1 is used.

In the drying apparatus used in the present invention, a plurality of wafers 4 may be loaded in a thermostat 1 configured to maintain a vacuum and to control temperature, and one side wall of the thermostat 1 may include a vacuum pump 3 and a vacuum pump 3. A connected exhaust port 2 is formed.

First, the cleaned wafer 4 is loaded and loaded into the thermostat 1, and then the temperature of the thermostat 1 is adjusted to 10 to 30 ° C. The vacuum pump 3 is operated so that the pressure in the thermostat 1 is 20 to 80 mmHg so that the cleaning liquid remaining on the surface of the wafer is vaporized.

By using this evaporation method, the solvent can be removed at room temperature, so that no degeneration of the material due to heat occurs and drying is possible within a short time. Therefore, the cleaning liquid (eg, pure water) present on the surface of the wafer is easily evaporated and removed.

However, a phenomenon in which the wafer is cooled and frozen due to latent heat of the cleaning liquid may occur. If the temperature of the wafer is kept constant, this phenomenon does not occur.

As described above, the present invention allows the cleaning liquid remaining on the surface of the wafer to be easily vaporized at room temperature and low pressure, thereby preventing damage or breakage of the wafer due to high speed rotation or high heat, and shortening drying time. As a result, defects due to wafer loss are reduced, and process time is shortened to increase the yield of devices.

Claims (6)

Adjusting the temperature inside the thermostat chamber after loading the cleaned wafer into the thermostat chamber; Wafer cleaning method comprising the step of adjusting the pressure in the thermostat so that the cleaning liquid remaining on the surface of the wafer is vaporized. The method of claim 1, Wafer drying method characterized in that the temperature inside the thermostat is adjusted to 10 to 30 ℃. The method of claim 1, Wafer drying method characterized in that the pressure in the thermostat is adjusted to 20 to 80mmHg. The method of claim 1, The pressure inside the thermostat is controlled by the operation of the vacuum pump wafer drying method. And a cleaning liquid remaining on the surface of the cleaned wafer at a room temperature and a pressure of 20 to 80 mmHg. The method of claim 5, The room temperature is a wafer drying method, characterized in that 10 to 30 ℃.