Supercritical drying method and apparatus for semiconductor substrates

1. A supercritical drying method for a semiconductor substrate, comprising:

cleaning the semiconductor substrate with a chemical solution;

rinsing the semiconductor substrate with pure water after the cleaning;

changing a liquid covering a surface of the semiconductor substrate from the pure water to alcohol by supplying the alcohol to the surface of the semiconductor substrate after the rinsing;

guiding the semiconductor substrate having the surface wetted with the alcohol, into a chamber containing steel use stainless (SUS), an inner wall face of the chamber being subjected to electrolytic polishing;

discharging oxygen from the chamber by supplying an inert gas into the chamber;

putting the alcohol into a supercritical state by increasing a temperature in the chamber to a critical temperature of the alcohol or higher after the discharge of the oxygen; and

discharging the alcohol from the chamber by lowering a pressure in the chamber and changing the alcohol from the supercritical state to a gaseous state.

2. The method according to claim 1 , wherein, prior to the supply of the inert gas, the alcohol with a fluid volume based on the a critical temperature and critical pressure of the alcohol, and on a volume of the chamber is supplied into the chamber.

3. The method according to claim 1 , wherein a metal film containing one of tungsten and molybdenum is formed on the semiconductor substrate.

4. The method according to claim 1 , wherein an oxygen density in an exhaust air from a glove box provided on the chamber is monitored, and the supply of the inert gas is continued until the oxygen density becomes a predetermined value or lower.

5. The method according to claim 1 , wherein the inert gas is one of a nitrogen gas, a carbon dioxide gas, or a rare gas.