TW291600B - Improved process of stacked dynamic random access memory - Google Patents

Abstract

A manufacturing method of dynamic random access memory with stacked capacitor with high capacitance and high packing density comprises of: (1) on one semiconductor substrate selectively forming field oxide region, leaving active area for implementing transistor; (2) on the above semiconductor substrate forming one transistor gate dielectric; (3) on the above active area in the above field oxide region depositing one doped first polysilicon, removing partial first polysilicon, leaving portion as transistor gate on the above active area, portion as memory word line on the above filed oxide region; (4) on semiconductor substrate on two sides of the above transistor gate forming source/drain structure; (5) on the above active and field oxide area forming one first insulator, and patterning node contact pattern, preparing for electric contact with capacitor storage node; (6) depositing one doped second polysilicon, second insulator and third polysilicon, and by plasma etch on capacitor region patterning the above third polysilicon pattern, and with etching stop on the above second insulator; (7) in high temperature environment with oxygen thermally oxidizing the above third polysilicon to form polyoxide; (8) with the above polyoxide as etch mask, by plasma etch vertically and anisotropically etching the above second polysilicon to some depth so as to from one very narrow trench in the middle of the above second polysilicon; (9) with chemical solution selectively removing the above polyoxide; (10) with chemical solution selectively removing the remaining part of the above second insulator; (11) patterning the above doped second polysilicon with one very narrow trench, forming storage node of stacked capacitor; (12) on the above capacitor storage node surface forming one capacitor dielectric; (13) depositing third polysilicon, by plasma etch patterning the above third polysilicon pattern, forming top electrode of stacked capacitor.