Film forming method
According to an embodiment of the present disclosure, a method of forming a polyimide film on a substrate is disclosed. Such method can be easily controlled and form a polyimide film applicable as an insulation film. While a wafer is heated at a temperature at which a polyimide film is formed, a cycle, in which the wafer is sequentially supplied with a first processing gas, for example, containing a PMDA-based first monomer, and a second processing gas containing a non-aromatic monomer, for example, an HMDA-based second monomer, is performed for a predetermined number of times. When the processing gases are switched, a replacement gas is supplied into a reaction tube so that the monomers are not mixed together under the atmosphere in the reaction tube.
1. A method of forming a polyimide film on a surface of a substrate by dehydration condensation of a first monomer including a bifunctional acid anhydride and a second monomer including a bifunctional amine, the method comprising:
loading the substrate into a processing chamber;
heating the substrate at a temperature for forming a polyimide film;
supplying the substrate with a first processing gas containing the first monomer and a second processing gas containing the second monomer; and
evacuating at least one of the first processing gas and the second processing gas from the processing chamber,
wherein the first and second monomers are aromatic and non-aromatic monomers, respectively,
wherein supplying the substrate with the processing gases comprises performing a cycle a predetermined number of times, the cycle including supplying a first processing gas containing the first monomer to the substrate, supplying a second processing gas containing the second monomer to the substrate, and supplying a replacement gas in the processing chamber between supplying the first processing gas and supplying the second processing gas thereby replacing atmosphere in the processing chamber by the replacement gas, and
wherein a film forming rate is at least 1.2 nm/cycle, and
wherein the second monomer as a non-aromatic monomer is HMDA.
2. The method of claim 1 , wherein heating the substrate includes heating the substrate to a temperature ranging from 100 degrees C. to 250 degrees C.
3. The method of claim 1 , wherein a concave portion is formed in the surface to be processed of the substrate, and the polyimide film is buried in the concave portion.
4. The method of claim 1 , wherein gas pressure in the processing chamber when the polyimide film is formed on the substrate is 13 Pa to 267 Pa.