Method for manufacturing a semiconductor device

A method for manufacturing a semiconductor device comprising the steps of:

• performing a first heat treatment in a chamber in which a substrate and a target are provided;
• forming an oxide semiconductor film over the substrate by sputtering method using the target;
• and
• performing a second heat treatment on the oxide semiconductor film,
• wherein the first heat treatment is performed at a temperature from 200° C. to 600° C.,
• wherein the oxide semiconductor film is formed in the chamber without exposure to air after the first heat treatment,
• wherein moisture remaining on an inner wall of the chamber and in the target is reduced by the first heat treatment, and
• wherein hydrogen or moisture in the oxide semiconductor film is reduced by the second heat treatment.

A method for manufacturing a semiconductor device comprising the steps of:

• performing a first heat treatment in a chamber in which a substrate and a target are provided;
• forming an oxide semiconductor film over the substrate by sputtering method using the target;
• and
• performing a second heat treatment on the oxide semiconductor film,
• wherein the oxide semiconductor film is formed in the chamber without exposure to air after the first heat treatment,
• wherein moisture remaining on an inner wall of the chamber and in the target is reduced by the first heat treatment,
• wherein moisture remaining in the chamber is reduced by a cryopump before, during or after forming the oxide semiconductor film, and
• wherein hydrogen or moisture in the oxide semiconductor film is reduced by the second heat treatment.