Lam Research Corporation

Supriya Goyal

Jisoo Kim

Dongho Heo

S M Reza Sadjadi

Sm Reza Sadjadi

A method for etching a dielectric layer is provided. A patterned mask with mask features is formed over a dielectric layer. The mask has isolated areas and dense areas of the mask features. The mask is trimmed by a plurality of cycles, where each cycle includes depositing a deposition layer, and selectively etching the deposition layer and the patterned mask. The selective etching selectively trims the isolated areas of the mask with respect to the dense areas of the mask. The dielectric layer is etched using the thus trimmed mask. The mask is removed.

Mask trimming

A method for etching a dielectric layer disposed below an antireflection layer (ARL) is provided. The method comprises (a) forming a patterned mask with mask features over the ARL, the mask having isolated areas and dense areas of the mask features, (b) trimming and opening, and (c) etching the dielectric layer using the trimmed mask. The trimming and opening comprises a plurality of cycles, where each cycle includes (b1) a trim-etch phase which etches the ARL in a bottom of the mask features and selectively trims the isolated areas of the mask with respect to the dense areas, and (b2) a deposition-etch phase which deposits a deposition layer on the mask while further etching the ARL in the bottom of the mask features. The trimming and opening result in a net trimming of the mask in the isolated areas.

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Emeryville, CA, United States of America

Supriya Goyal