US 9,812,327 B2
Semiconductor device and method of forming the same
Kun-Huang Yu, New Taipei (TW); and Shih-Yin Hsiao, Chiayi County (TW)
Assigned to United Microelectronics Corp., Hsinchu (TW)
Filed by United Microelectronics Corp., Hsinchu (TW)
Filed on Sep. 23, 2015, as Appl. No. 14/863,177.
Claims priority of application No. 2015 1 0521058 (CN), filed on Aug. 24, 2015.
Prior Publication US 2017/0062444 A1, Mar. 2, 2017
Int. Cl. H01L 21/28 (2006.01); H01L 29/423 (2006.01); H01L 27/11536 (2017.01); H01L 27/11539 (2017.01)
CPC H01L 21/28273 (2013.01) [H01L 27/11536 (2013.01); H01L 27/11539 (2013.01); H01L 29/42336 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A semiconductor device, comprising:
a substrate having a cell area and a MOS device area;
a first gate, buried in an opening of the substrate in the cell area;
a second gate, disposed on the substrate in the cell area, wherein the second gate comprises metal;
an inter-gate dielectric layer, disposed between the first gate and the second gate; and
a third gate, disposed on the substrate in the MOS device area, wherein the third gate comprises metal,
wherein the inter-gate dielectric layer is in physical contact with an upper sidewall of the opening and further extends to directly cover a top corner of the opening, and
wherein an upper surface of the second gate and an upper surface of the third gate are coplanar and a bottom surface of the second gate and a bottom surface of the third gate are coplanar.