Lam Research Corporation

Sam Do Lee

Harmeet Singh

Qian Fu

Zhongkui Tan

Shenjian Liu

Ce Qin

Linda Fung-Ming Lee

Sok Kiow Tan

A method for forming a stair-step structure in a stack on a substrate is provided. The method comprises at least one stair step cycle. Each stair step cycle comprises trimming the mask and etching the stack. Etching the stack is provided in a plurality of cycles wherein each cycle comprises etching a SiOlayer and etching a SiN layer. Etching a SiOlayer comprises flowing a SiOetching gas into the plasma processing chamber, wherein the SiOetching gas comprises a hydrofluorocarbon, an inert bombardment gas, and at least one of SFand NF, generating a plasma from the SiOetching gas, providing a bias, and stopping the SiOlayer etch. The etching a SiN layer comprises flowing a SiN etching gas into the plasma processing chamber, comprising a hydrofluorocarbon and oxygen, generating a plasma from the SiN etching gas, providing a bias, and stopping the SiN layer etch.

Silicon oxide silicon nitride stack stair step etch

The embodiments provides an improved tungsten silicide etching process with reduced etch rate micro-loading effect. In one embodiment, a method for etching a layer formed on a substrate is provided. The method includes providing a substrate into a plasma processing chamber, the substrate having a metal silicide layer formed thereon and a patterned mask defined over the metal silicide layer. The method also includes supplying an etching gas mixture of a fluorine-containing gas, a chlorine-containing gas, a nitrogen-containing gas, and an oxygen-containing gas to the plasma processing chamber, wherein the ratio of the nitrogen-containing gas to the fluorine-containing gas is between about 5 to about 15. In addition, the method includes generating a plasma in the plasma processing chamber using the supplied etching gas mixture to etch the metal silicide layer in regions not covered by the patterned mask, the patterned mask defining dense regions and isolated regions, wherein the generated plasma is configured to remove the metal silicide layer in the dense regions and the isolated regions at a reduced etch rate micro-loading.

Tungsten silicide etch process with reduced etch rate micro-loading

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Fremont, CA, United States of America

Sam Do Lee