Sputtering target and manufacturing method thereof, and transistor
One object is to provide a deposition technique for forming an oxide semiconductor film. By forming an oxide semiconductor film using a sputtering target including a sintered body of a metal oxide whose concentration of hydrogen contained is low, for example, lower than 1×10 16 atoms/cm 3 , the oxide semiconductor film contains a small amount of impurities such as a compound containing hydrogen typified by H 2 O or a hydrogen atom. In addition, this oxide semiconductor film is used as an active layer of a transistor.
1. A manufacturing method of a sputtering target, comprising:
mixing and baking a plurality of metal oxides to form a sintered body;
performing a mechanical processing on the sintered body so as to form a target;
cleaning the target; and
performing a heat treatment on the cleaned target.
2. The manufacturing method according to claim 1 , wherein the cleaning step is performed by an ultrasonic cleaning.
3. The manufacturing method according to claim 1 , wherein a temperature of the heat treatment is 425° C. to 750° C. inclusive.
4. The manufacturing method according to claim 1 , wherein the heat treatment is performed so that a concentration of hydrogen atom contained in the sintered body is lower than 1×10 16 atoms/cm 3 .
5. The manufacturing method according to claim 1 ,
wherein the heat treatment is performed in a heat treatment apparatus into which at least one gases of nitrogen, helium, neon and argon is introduced,
wherein a purity of the at least one gases is set to be 6N or 7N or higher, and
wherein the 6N is 99.9999% and the 7N is 99.99999%.
6. The manufacturing method according to claim 1 , wherein the plurality of metal oxides includes zinc oxide, gallium oxide, and indium oxide.
7. A manufacturing method of a sputtering target, comprising:
mixing and baking a plurality of metal oxides to form a sintered body;
performing a mechanical processing on the sintered body so as to form a target;
cleaning the target;
performing a heat treatment on the cleaned target; and
attaching the target to a backing plate.
8. The manufacturing method according to claim 7 , wherein the cleaning step is performed by an ultrasonic cleaning.
9. The manufacturing method according to claim 7 , wherein a temperature of the heat treatment is 425° C. to 750° C. inclusive.
10. The manufacturing method according to claim 7 , wherein the heat treatment is performed so that a concentration of hydrogen atom contained in the sintered body is lower than 1×10 16 atoms/cm 3 .
11. The manufacturing method according to claim 7 ,
wherein the heat treatment is performed in a heat treatment apparatus into which at least one gases of nitrogen, helium, neon and argon is introduced,
wherein a purity of the at least one gases is set to be 6N or 7N or higher, and
wherein the 6N is 99.9999% and the 7N is 99.99999%.
12. The manufacturing method according to claim 7 , wherein the plurality of metal oxides includes zinc oxide, gallium oxide, and indium oxide.
13. The manufacturing method according to claim 1 , wherein the filling rate of the sputtering target for film formation is 90% or higher.
14. The manufacturing method according to claim 7 , wherein the filling rate of the sputtering target for film formation is 90% or higher.
15. The manufacturing method according to claim 1 , wherein the heat treatment is performed so that a concentration of hydrogen atom contained in the sintered body is lower than 5×10 19 atoms/cm 3 .
16. The manufacturing method according to claim 7 , wherein the heat treatment is performed so that a concentration of hydrogen atom contained in the sintered body is lower than 5×10 19 atoms/cm 3 .