Plasma etching chemistries of high aspect ratio features in dielectrics

Patent metadata

Field	Value
Publication number	US-12119243-B2
Application number	US-202318163522-A
Country	US
Kind code	B2
Filing date	Feb 2, 2023
Priority date	Mar 16, 2018
Publication date	Oct 15, 2024
Grant date	Oct 15, 2024

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.

First claim

What is claimed is:

1. 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 SiF 4 , TaF 5 , BrF 5 , AsF 5 , NF 5 , PF 5 , NbF 5 , BiF 5 , UF 5 , SiCl 2 , CrO 2 Cl 2 , TaCl 4 , HfCl 4 , TiCl 3 (1), CoCl 2 (1), TiCl 3 , CCl 4 , CBr 2 F 2 , C 2 F 5 Br, H 2 O, H 2 O 2 , BCl 3 , NH 3 , SiF 4 , CrO 2 Cl 2 , SiCl 4 , TiCl 2 , TiCl 3 , CoCl 2 , and TiCl 2 ;
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. The method, as recited in claim 1 , further comprising providing a bias with a magnitude of at least 400 volts.

3. The method, as recited in claim 1 , wherein the etch gas is oxygen free.

4. The method, as recited in claim 1 , wherein the stack is cooled to a temperature below −60° C.

5. The method, as recited in claim 1 , wherein the stack is cooled to a temperature in the range of −20° C. to −60° C.

Assignees

• Lam Res Corp

Inventors

• Kanarik Keren J
• Tan Samantha Siamhwa
• Pan Yang
• Marks Jeffrey

Classifications

• H10P72/722

  Details of electrostatic chucks · CPC title

• H10P72/0434

  mainly by convection · CPC title

• H10W20/069

  by forming self-aligned vias or self-aligned contact plugs · CPC title

• H10P72/0421 Primary

  for drying etching · CPC title

• H10P72/72

  using electrostatic chucks · CPC title