US 9,812,587 B2
Semiconductor device and manufacturing method thereof
Shunpei Yamazaki, Tokyo (JP)
Assigned to Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken (JP)
Filed by Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken (JP)
Filed on Jan. 20, 2016, as Appl. No. 15/1,834.
Claims priority of application No. 2015-012200 (JP), filed on Jan. 26, 2015; and application No. 2015-012530 (JP), filed on Jan. 26, 2015.
Prior Publication US 2016/0218225 A1, Jul. 28, 2016
Int. Cl. H01L 21/00 (2006.01); H01L 29/786 (2006.01); H01L 27/12 (2006.01); H01L 29/45 (2006.01); H01L 29/49 (2006.01); H01L 29/66 (2006.01)
CPC H01L 29/78696 (2013.01) [H01L 27/1225 (2013.01); H01L 27/1251 (2013.01); H01L 27/1259 (2013.01); H01L 29/45 (2013.01); H01L 29/4908 (2013.01); H01L 29/66969 (2013.01); H01L 29/7869 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method for manufacturing a semiconductor device, comprising the steps of:
forming a first insulator;
forming a second insulator over the first insulator;
forming an opening reaching the first insulator in the second insulator;
forming a first conductor over the second insulator and the first insulator; forming a second conductor over the first conductor;
forming a first conductor layer including the first conductor and the second conductor by removing the second conductor and the first conductor which are positioned above a top surface of the second insulator by chemical mechanical polishing;
forming a third insulator over the second insulator and the first conductor layer;
forming a first oxide semiconductor over the third insulator;
forming a second oxide semiconductor over the first oxide semiconductor;
forming an island-shaped oxide semiconductor layer including the first oxide semiconductor and the second oxide semiconductor by etching part of the first oxide semiconductor and the second oxide semiconductor;
forming a third conductor over the third insulator and the island-shaped oxide semiconductor layer;
forming a second conductor layer including the third conductor by etching part of the third conductor;
forming a fourth insulator over the third insulator and the second conductor layer;
dividing the second conductor layer into a third conductor layer and a fourth conductor layer by forming an opening reaching a surface of the third insulator and an opening reaching a surface of the island-shaped oxide semiconductor layer in the fourth insulator and the second conductor layer;
forming a third oxide semiconductor over the fourth insulator and the island-shaped oxide semiconductor layer;
forming a fifth insulator over the third oxide semiconductor;
forming a fourth conductor over the fifth insulator;
forming a fifth conductor layer including the fourth conductor by etching part of the fourth conductor;
etching part of the fifth insulator;
etching part of the third oxide semiconductor; and
forming a sixth insulator over the fourth insulator and the fifth conductor layer,
wherein the fifth insulator comprises a region thinner than the third conductor layer and the fourth conductor layer.