Film forming method, fabrication process of semiconductor device, computer-readable recording medium and sputtering apparatus
A film-forming method for forming a metal film on a substrate by a sputtering process includes the steps of depressurizing a processing space, in which deposition of the metal film is caused by the sputtering process, applying a DC bias voltage between the substrate and a target disposed in the processing space so as to face the substrate, and igniting plasma by introducing secondary electrons to the processing space from a secondary electron source.
1. A film-forming method for forming a metal film on a substrate by a sputtering process, comprising:
depressurizing a processing space, in which deposition of said metal film is caused by said sputtering process;
applying a DC bias voltage between said substrate and a target disposed in said processing space so as to face said substrate; and
igniting plasma by introducing secondary electrons to said processing space from a secondary electron source,
wherein said secondary electron source is an ion gauge comprising: a thermal electron source; a grid provided around said thermal electron source, said grid being applied with a positive voltage; and a collector provided in the vicinity of said grid and collecting positive ions,
wherein said ion gauge is provided in a space which is different from the processing space, and
wherein said collector is provided at the periphery of the grid.
2. The method as claimed in claim 1 , wherein said metal film is a magnetic metal film.
3. The method as claimed in claim 1 , wherein said igniting plasma forms said secondary electrons by: emitting thermal electrons by driving said thermal electron source; and causing said thermal electrons to collide with said grid by applying a positive voltage to said grid.
4. The method as claimed in claim 1 , wherein said thermal electron source is deenergized after said igniting plasma in a state in which said plasma is sustained.
5. The method as claimed in claim 4 , wherein said thermal electron source is deenergized after said igniting plasma, after a predetermined time.
6. The method as claimed in claim 1 , wherein said thermal electron source comprises a filament of a platinum group metal.
7. The method as claimed in claim 1 , wherein said measurement of degree of vacuum by said ion gauge is stopped in said igniting plasma.
8. The method as claimed in claim 1 , wherein said collector is grounded in said step of igniting plasma.
9. The method as claimed in claim 1 , wherein said sputtering process is conducted by a DC sputtering process by applying a DC bias between said substrate and said target by a DC power supply.
10. The method as claimed in claim 1 , wherein said ion gauge is used to measure degree of vacuum of said processing space during said depressurizing said processing space.