Macronix International Co., Ltd.

Shu-Li Wu

Pei-Ren Jeng

Ping-Yi Chang

Wan-Yi Liu

The present invention provides a method for forming a flash memory cell and comprises following steps. First, a substrate is provided. Then, a gate dielectric layer, a first polysilicon layer and a hard mask layer are sequentially formed on the substrate. Next, a portion of the hard mask layer, the polysilicon layer, and the gate dielectric layer are removed to form a plurality of holes to expose the substrate. Following, a dielectric layer is formed in those holes by a HDPCVD process. Last, the hard mask layer on the first polysilicon layer is removed by the HDPCVD process. Further, a second polysilicon layer could be conformally formed on the first polysilicon layer and the isolation dielectric.

Method for forming flash memory cell

A method for forming a high-RI dielectric liner layer to prevent out diffusion of fluorine substances in an intermetal dielectric (IMD) layer of an semiconductor device is provided. The method comprises following steps. First, a patterned conductive layer is deposited on a substrate. Then, a dielectric liner layer is formed by high density plasma enhanced chemical vapor deposition method or plasma enhanced chemical vapor deposition method. The dielectric liner layer is silicon dioxide and has a high-RI between about 1.5 to 1.8. Next, a fluorinated silicate glass layer is deposited on the dielectric liner layer. The high-RI dielectric liner layer is used to reduce out diffusion of fluorine substances in the fluorinated silicate glass layer. Last, it is proceeded a chemical mechanism polishing process to remove additional fluorinated silicate glass layer and the dielectric liner layer.

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Nan-Tao, Taiwan

Shu-Li Wu