Mosel Vitelic Corporation

Promos Technologies, Inc

Hua Ji

Jin-Ho Kim

Chuck Jang

Dong Jun Kim

A method and structure to form shallow trench isolation regions without trench oxide grooving is provided. In particular, a method includes a two-step oxide process in which an oxide liner lines the inside surface of a trench and the trench is filled with a bulk oxide layer, preferably using a high density plasma chemical vapor deposition (HDP-CVD) process. The oxide liner and the bulk oxide layer are formed to have similar etch rates. Thus, when etching the oxide liner and the bulk oxide layer between stack structures, a common dielectric top surface is formed that is substantially planar and without grooves.

Trench isolation without grooving

Method of forming trench isolation without grooving

A method is provided for advantageously etching dielectric material between highly integrated polysilicon devices with high dielectric-to-polysilicon selectivity to expose polysilicon with minimal polysilicon loss and without photoresist lift. A wet etch solution comprising surfactant and between about 0% and about 10% NH F is used to wet etch the dielectric material and reduce polysilicon loss thickness, polysilicon resistance ratios, and polysilicon etch rates, while increasing dielectric-to-polysilicon selectivity. Advantageously, the present invention may penetrate into increasingly small geometries of highly integrated devices and may also be used for general wet etches of dielectric material in conjunction with photoresist.

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San Jose, CA, United States of America

Hua Ji