Method for forming coating film on a plate-like workpiece

Abstract

The present invention aims at maintaining a low dielectric constant in a case of forming an interlayer insulation film by baking SOG. When a plate-like material to be treated W, on the surface of which an applying film is formed, is entered into an apparatus, an elevator means 3 is lowered, so that the plate-like material to be treated W comes close to the cool plate 2, and further N 2 gas is introduced into the apparatus. Then, the oxygen concentration in the atmosphere is reduced to less than or equal to 1% before the surface temperature of the plate-like material to be treated W rises to 200° C. Thereafter, while maintaining the oxygen concentration to be less than or equal to 1%, the elevator means 3 is elevated, so that the plate-like material to be treated W comes close to the hot plate 1, and the surface of the plate-like material to be treated W is heated to be greater than or equal to 400° C. After such a condition is continued for a predetermined period of time, the temperature is lowered. In this instance, the oxygen concentration in the atmosphere is maintained to be less than or equal to 1% until the surface temperature of the plate-like material to be treated W lowers to 200° C.

What is claimed is:  
     
         1 . A method for forming a coating film, comprising the following steps: 
 applying a raw material of a low dielectric constant onto a surface of a plate-like material to be treated such as a semiconductor wafer and a glass substrate;    reducing the oxygen concentration in the atmosphere to be less than or equal to 1% before the surface temperature of said plate-like material to be treated rises to 200° C.; thereafter    heating said plate-like material to be treated to be greater than or equal to 400° C. while maintaining the oxygen concentration in the atmosphere to be less than or equal to 1%; and then    maintaining the oxygen concentration in the atmosphere to be less than or equal to 1% until the surface temperature of said plate-like material to be treated lowers to 200° C.    
     
     
         2 . A method for forming a coating film as defined in    claim 1   , wherein the oxygen concentration in the atmosphere is lowered to be less than or equal to 1% by purging N 2  gas.  
     
     
         3 . A method for forming a coating film as defined in    claim 1   , wherein said method is conducted in one baking furnace, in the upper portion of which is positioned a hot plate, while in the lower portion of which is positioned a cool plate, in which said plate-like material to be treated comes close to either one of said hot plate and said cool plate selectively by means of an elevator means.  
     
     
         4 . A method for forming a coating film as defined in any one of claims  1  through  3 , wherein said method is applied to a forming of an interlayer insulation film by a damascene method.