Taiwan Semiconductor Manufacturing Comp. Ltd.

Hsiu Ouyang

Chia-Shiung Tsai

Chi-Hsin Lo

Yeur-Luen Tu

Chia-Ta Hsieh

Chen-Ming Huang

Yuan-Hung Liu

Tsung-Hsun Huang

Chin-Ta Wu

A split gate FET wordline electrode structure and method for forming the same including an improved polysilicon etching process including providing a semiconductor wafer process surface comprising first exposed polysilicon portions and adjacent oxide portions; forming a first oxide layer on the exposed polysilicon portions; blanket depositing a polysilicon layer on the first exposed polysilicon portions and adjacent oxide portions; forming a hardmask layer on the polysilicon layer; carrying out a multi-step reactive ion etching (RIE) process to etch through the hardmask layer and etch through a thickness portion of the polysilicon layer to form second polysilicon portions adjacent the oxide portions having upward protruding outer polysilicon fence portions; contacting the semiconductor wafer process surface with an aqueous HF solution; and, carrying out a downstream plasma etching process to remove polysilicon fence portions.

Etching method for forming a square cornered polysilicon wordline electrode

A method of fabricating word-line spacers comprising the following steps. A substrate having an inchoate split-gate flash memory structure formed thereover is provided. A conductive layer is formed over the substrate and the inchoate split-gate flash memory structure. The conductive layer having: a upper portion and lower vertical portions over the inchoate split-gate flash memory structure; and lower horizontal portions over the substrate. A dual-thickness oxide layer is formed over the conductive layer and has a greater thickness over the upper portion of the conductive layer. The oxide layer is partially etched back to remove at least the oxide layer from over the lower horizontal portions of the conductive layer to expose the underlying portions of the conductive layer. Then etching: away the exposed portions of the conductive layer over the substrate; and through at least a portion of the thinned oxide layer and into the exposed underlying portion of the conductive layer to expose a portion of the inchoate split-gate flash memory structure and to form the word-line spacers adjacent the inchoate split-gate flash memory structure.

Methods of fabricating a word-line spacer for wide over-etching window on outside diameter (OD) and strong fence

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Taipei, Taiwan

Hsiu Ouyang