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US 11,769,727 B2Granted
Semiconductor memory device
AssigneesUnited Microelectronics Corp., Fujian Jinhua Integrated Circuit Co., Ltd.
InventorsFeng-Yi Chang, Shih-Fang Tzou, Fu-Che Lee, Chien-Cheng Tsai, Feng-Ming Huang
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Abstract
A semiconductor memory device and a manufacturing method thereof are provided in the present invention. An under-cut structure is formed at an edge of a bit line contact opening in the process of forming the bit line contact opening for avoiding short problems caused by alignment shifting, and the process window of the process of forming the bit line contact opening may be improved accordingly.
Claims13
A semiconductor memory device, comprising:
- a semiconductor substrate comprising a plurality of active regions;
- a plurality of shallow trench isolations disposed in the semiconductor substrate, wherein each of the plurality of shallow trench isolation is disposed between the plurality of active regions;
- a bit line contact opening disposed in one of the plurality of active regions and disposed in the plurality of shallow trench isolations, wherein an edge of the bit line contact opening has an under-cut structure;
- a bit line structure partially disposed in the bit line contact opening and in contact with one of the plurality of active regions corresponding to the bit line contact opening;
- and
- an isolation structure disposed in the under-cut structure of the bit line contact opening, wherein a distance between a sidewall of the bit line structure and a topmost portion of an outermost sidewall of the under-cut structure is less than a distance between the sidewall of the bit line structure and a bottommost portion of the outermost sidewall of the under-cut structure;
- and
- wherein the outermost sidewall of the under-cut structure consists of a planar surface and a cross-section of the isolation structure comprises a triangle.
5 more elements
Dependencies are inferred from the claim text.