Yangtze Memory Technologies Co., Ltd.

Lipeng Liu

Yu Wang

Lianjuan Ren

Wenjie Zhang

Hong Guang Song

Hongguang Song

Yuqi Wang

In a method, a mask is formed on a microstructure over a substrate. The mask includes a first pattern over a first region of the microstructure and a second pattern over a second region of the microstructure. A first etching process is performed to etch the microstructure by providing an etching gas and applying a first bias voltage to the substrate according to the first and second patterns of the mask. A protective layer is subsequently formed by providing a deposition gas and applying a second bias voltage to the substrate to cover the first pattern of the mask. A second etching process is performed to transfer the second pattern of the mask further into the second region of the microstructure. The deposition gas has a higher carbon to fluorine ratio than the etching gas, and the second bias voltage is smaller than the first bias voltage.

Etching process with in-situ formation of protective layer

In the disclosed method, a mask is formed on a microstructure. The mask includes a first pattern positioned over a first region of the microstructure and a second pattern positioned over a second region of the microstructure. A first etching process is performed to etch the microstructure according to the first and second patterns formed in the mask. The first etching process transfers the first and second patterns of the mask into the first and second regions of the microstructure, respectively. A protective layer is subsequently formed over the first pattern of the mask that is positioned over the first region of the microstructure. When the protective layer is formed, a second etching process is performed to etch the microstructure and transfer the second pattern of the mask further into the second region of the microstructure. The method also includes removing the mask and the protective layer from the microstructure.

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Wuhan, China

Lipeng Liu