Method for manufacturing semiconductor device
To reduce defects in an oxide semiconductor film in a semiconductor device. To improve electrical characteristics of and reliability in the semiconductor device including an oxide semiconductor film. A method for manufacturing a semiconductor device includes the steps of forming a gate electrode and a gate insulating film over a substrate, forming an oxide semiconductor film over the gate insulating film, forming a pair of electrodes over the oxide semiconductor film, forming a first oxide insulating film over the oxide semiconductor film and the pair of electrodes by a plasma CVD method in which a film formation temperature is 280° C. or higher and 400° C. or lower, forming a second oxide insulating film over the first oxide insulating film, and performing heat treatment at a temperature of 150° C. to 400° C. inclusive, preferably 300° C. to 400° C. inclusive, further preferably 320° C. to 370° C. inclusive.
1. A method for manufacturing a semiconductor device, comprising the steps of:
forming a first gate electrode over a substrate;
forming a gate insulating film over the first gate electrode;
forming an oxide semiconductor film over the gate insulating film;
forming a pair of electrodes electrically connected to the oxide semiconductor film without performing heat treatment after the oxide semiconductor film is formed;
forming a first oxide insulating film over the oxide semiconductor film by a plasma CVD,
wherein a film formation temperature of the first oxide insulating film is higher than or equal to 280° C. and lower than or equal to 400° C.;
forming a second oxide insulating film over the first oxide insulating film; and
performing heat treatment at a temperature higher than or equal to 150° C. and lower than or equal to 400° C.,
wherein the heat treatment is performed after forming the pair of the electrodes.
2. The method for manufacturing a semiconductor device according to claim 1 ,
wherein a treatment chamber is evacuated and a pressure in the treatment chamber is set to be greater than or equal to 100 Pa and less than or equal to 250 Pa by introducing a source gas into the treatment chamber, and
wherein the first oxide insulating film is formed in the treatment chamber by supplying a high-frequency power to an electrode provided in the treatment chamber.
3. The method for manufacturing a semiconductor device according to claim 1 ,
wherein a treatment chamber is evacuated and a pressure in the treatment chamber is set to be greater than or equal to 100 Pa and less than or equal to 250 Pa by introducing a source gas into the treatment chamber,
wherein the second oxide insulating film is formed in the treatment chamber by supplying a high-frequency power higher than or equal to 0.17 W/cm 2 and lower than or equal to 0.5 W/cm 2 to an electrode provided in the treatment chamber, and
wherein a temperature of the substrate placed in the treatment chamber is a temperature higher than or equal to 180° C. and lower than or equal to 280° C.
4. The method for manufacturing a semiconductor device according to claim 1 ,
wherein, as the first oxide insulating film and the second oxide insulating film, a silicon oxide film or a silicon oxynitride film is formed using a deposition gas containing silicon and an oxidizing gas as a source gas.
5. The method for manufacturing a semiconductor device according to claim 1 ,
wherein, as the first oxide insulating film and the second oxide insulating film, a silicon oxynitride film is formed using silane and dinitrogen monoxide as a source gas.
6. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the oxide semiconductor film comprises at least one of In and Ga.
7. The method for manufacturing a semiconductor device according to claim 1 further comprising:
forming a nitride insulating film over the second oxide insulating film.
8. The method for manufacturing a semiconductor device according to claim 7 further comprising:
forming a second gate electrode over the nitride insulating film.
9. A method for manufacturing a semiconductor device, comprising the steps of:
forming a gate electrode over a substrate;
forming a gate insulating film over the gate electrode;
forming an oxide semiconductor film over the gate insulating film;
forming an oxide film over the oxide semiconductor film;
forming a pair of electrodes electrically connected to the oxide semiconductor film over the oxide film, without performing heat treatment after the oxide film is formed;
forming a first oxide insulating film over the oxide film and the pair of electrodes by a plasma CVD,
wherein a film formation temperature of the first oxide insulating film is higher than or equal to 280° C. and lower than or equal to 400° C.;
forming a second oxide insulating film over the first oxide insulating film; and
performing heat treatment at a temperature higher than or equal to 150° C. and lower than or equal to 400° C.,
wherein the heat treatment is performed after forming the pair of the electrodes.
10. The method for manufacturing a semiconductor device according to claim 9 ,
wherein a treatment chamber is evacuated and a pressure in the treatment chamber is set to be greater than or equal to 100 Pa and less than or equal to 250 Pa by introducing a source gas into the treatment chamber, and
wherein the first oxide insulating film is formed in the treatment chamber by supplying a high-frequency power to an electrode provided in the treatment chamber.
11. The method for manufacturing a semiconductor device according to claim 9 ,
wherein a treatment chamber is evacuated and a pressure in the treatment chamber is set to be greater than or equal to 100 Pa and less than or equal to 250 Pa by introducing a source gas into the treatment chamber,
wherein the second oxide insulating film is formed in the treatment chamber by supplying a high-frequency power higher than or equal to 0.17 W/cm 2 and lower than or equal to 0.5 W/cm 2 to an electrode provided in the treatment chamber, and
wherein a temperature of the substrate placed in the treatment chamber is a temperature higher than or equal to 180° C. and lower than or equal to 280° C.
12. The method for manufacturing a semiconductor device according to claim 9 ,
wherein, as the first oxide insulating film and the second oxide insulating film, a silicon oxide film or a silicon oxynitride film is formed using a deposition gas containing silicon and an oxidizing gas as a source gas.
13. The method for manufacturing a semiconductor device according to claim 9 ,
wherein, as the first oxide insulating film and the second oxide insulating film, a silicon oxynitride film is formed using silane and dinitrogen monoxide as a source gas.
14. The method for manufacturing a semiconductor device according to claim 9 ,
wherein the oxide semiconductor film comprises at least one of In and Ga.
15. The method for manufacturing a semiconductor device according to claim 9 ,
wherein the oxide film comprises at least one of elements included in the oxide semiconductor film.
16. The method for manufacturing a semiconductor device according to claim 9 ,
wherein a conduction band bottom of the oxide film is closer to a vacuum level than a conduction band bottom of the oxide semiconductor film is.
17. The method for manufacturing a semiconductor device according to claim 9 further comprising:
forming a nitride insulating film over the second oxide insulating film.
18. A method for manufacturing a semiconductor device, comprising the steps of:
forming a first gate electrode over a substrate;
forming a gate insulating film over the first gate electrode;
forming an oxide semiconductor film over the gate insulating film;
forming a pair of electrodes electrically connected to the oxide semiconductor film after the oxide semiconductor film is formed;
forming a first oxide insulating film over the oxide semiconductor film by a plasma CVD, wherein a film formation temperature of the first oxide insulating film is higher than or equal to 280° C. and lower than or equal to 400° C.;
forming a second oxide insulating film over the first oxide insulating film; and
performing heat treatment at a temperature higher than or equal to 150° C. and lower than or equal to 400° C.,
wherein no heat treatment is performed during a period between completion of the oxide semiconductor film forming step and completion of the pair of electrodes forming step.