Macronix International Co., Ltd.

Cheng-Shun Chen

June-Min Yao

Shu-Ya Hsu

A method of shallow trench isolation fill-in to create the void-free trenches is disclosed. First, a liner oxide layer is formed in the trenches. Next, the silicon substrate is pre-wetted with DI water, and the liner oxide layer is etched by a chemical solution. The chemical solution is an oxide etchant, such as HF solution or BOE (buffered oxide etchant). The etching rate close to an opening of a trench is faster than a bottom of the trench. Finally, the trenches are filled with a HDP oxide layer.

Method of shallow trench isolation fill-in without generation of void

Multiple oxide layers with different thicknesses are formed on a semiconductor substrate with a silicon surface, having a first and second region. A sacrificial oxide layer is formed on the silicon surface to cover both the first region and the second region, with a mask layer formed on the surface of the sacrificial oxide layer. By defining and patterning the mask layer, a first opening and a second opening, having predetermined surface areas, are formed in portions of the first and second regions of the mask layer to expose portions of the. The sacrificial oxide layer has a surface area equal to the first predetermined surface area, and portions of the sacrificial oxide layer having a surface area equal to the second predetermined surface area. A linear nitrogen doping process is then performed to simultaneously implant nitrogen ions with a first and second predetermined concentration into the first and second region, through the first opening and the second opening, respectively. Thereafter, the mask layer and the sacrificial oxide layer are removed, respectively. An oxidation process is performed to two silicon oxide layers with different thicknesses in the first and second regions.

Growing community of inventors

Miaoli, Taiwan

Cheng-Shun Chen