US 12,328,908 B2
Semiconductor device and method for manufacturing semiconductor device
Tetsuya Kakehata, Kanagawa (JP); and Yuta Endo, Kanagawa (JP)
Assigned to Semiconductor Energy Laboratory Co., Ltd., (JP)
Filed by Semiconductor Energy Laboratory Co., Ltd., Kanagawa-ken (JP)
Filed on Jun. 20, 2023, as Appl. No. 18/212,018.
Application 18/212,018 is a division of application No. 17/048,255, granted, now 11,705,524, previously published as PCT/IB2019/053112, filed on Apr. 16, 2019.
Claims priority of application No. 2018-086200 (JP), filed on Apr. 27, 2018.
Prior Publication US 2023/0343856 A1, Oct. 26, 2023
Int. Cl. H10D 30/67 (2025.01); H01L 21/02 (2006.01); H10D 30/01 (2025.01); H10D 62/80 (2025.01); H10D 99/00 (2025.01)
CPC H10D 30/6755 (2025.01) [H01L 21/02178 (2013.01); H01L 21/02183 (2013.01); H01L 21/02186 (2013.01); H01L 21/02266 (2013.01); H01L 21/0228 (2013.01); H10D 30/031 (2025.01); H10D 30/6734 (2025.01); H10D 62/80 (2025.01); H10D 99/00 (2025.01)] 10 Claims
OG exemplary drawing
 
1. A method of manufacturing a semiconductor device, comprising steps of:
forming a first insulator over a substrate;
forming a first oxide film and a first conductive film over the first insulator;
forming a first insulating film and a second insulating film over the first conductive film;
forming an opening reaching the first oxide film in the first conductive film, the first insulating film, and the second insulating film;
forming a third insulating film in the opening;
forming a second conductive film over the third insulating film so that a thickness of the second conductive film at a bottom portion of the opening is larger than a thickness of the second conductive film at a side portion of the opening;
etching the second conductive film at the side portion of the opening so that the second conductive film at the bottom portion of the opening is left;
forming a fourth insulating film over the second conductive film;
forming a third conductive film over the second conductive film; and
performing planarization treatment until the second insulating film is exposed.