United Microelectronics Corp.

Cheng-Han Lu

Po-Wen Su

A method for fabricating a semiconductor device includes following steps: A patterned mask layer including a plurality of standing walls and a covering part is formed on a surface of a semiconductor substrate, wherein two adjacent standing walls define a first opening exposing a part of the surface, and the covering part blankets the surface. A first patterned photoresist layer is formed to partially cover the covering part. A first etching process is performed to form a first trench in the substrate, passing through the surface and aligning with the first opening. A portion of the patterned mask layer is removed to form a second opening exposing another portion of the surface. A second etching process is performed to form a second trench in the substrate and define an active area on the surface. The depth of the first trench is greater than that of the second trench.

Growing community of inventors

Chiayi, Taiwan

Cheng-Han Lu