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US 12,119,243 B2Granted
Plasma etching chemistries of high aspect ratio features in dielectrics
AssigneeLam Research Corporation
InventorsKeren J. Kanarik, Samantha Siamhwa Tan, Yang Pan, Jeffrey Marks
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Abstract
A method for etching features in a stack below a patterned mask in an etch chamber is provided. The stack is cooled with a coolant with a coolant temperature below −20° C. An etch gas is flowed into the etch chamber. A plasma is generated from the etch gas. Features are selectively etched into the stack with respect to the patterned mask.
Claims5
A method for etching a stack, comprising:
- a) cooling the stack to a temperature below −20° C.;
- b) flowing an etch gas into the etch chamber, wherein the etch gas comprises at least one of SiF4, TaF5, BrF5, AsF5, NF5, PF5, NbF5, BiF5, UF5, SiCl2, CrO2Cl2, TaCl4, HfCl4, TiCl3(1), CoCl2(1), TiCl3, CCl4, CBr2F2, C2F5Br, H2O, H2O2, BCl3, NH3, SiF4, CrO2Cl2, SiCl4, TiCl2, TiCl3, CoCl2, and TiCl2;
- c) generating a plasma from the etch gas;
- and
- d) selectively etching features in the stack with respect to a patterned mask, wherein the stack is comprised of alternating layers of silicon oxide and polysilicon.
2 more elements
Dependencies are inferred from the claim text.