Dry etching method

• US 5,078,833 A
• Filed: 07/20/1990
• Issued: 01/07/1992
• Est. Priority Date: 07/21/1989
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kadomura, Shingo
• Primary Examiner(s): Powell, William A.
• Application Number:
  US07/555,032
• Time in Patent Office: 536 Days
• Field of Search: 156/643, 156/646, 156/647, 156/648, 156/653, 156/657, 156/659.1, 156/662, 252/79.1, 204/192.37, 427/38, 427/39
• US Class Current: 438/696
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/3085 characterised by their behaviour during the process, e.g. soluble masks, redeposited masks

Abstract

A dry etching process utilizes a gas to form a side wall protecting layer, which gas has added at least chlorine trifluoride, or in the alternative silicon and fluorine as component.

Claims

1. A composite gas for dry etching for forming a desired configuration of trench in a monocrystalline silicon, composed of:

a base composite gas for etching the monocrystalline silicon; and

an additive gas added to said base composite gas, said additive gas containing at least Cl F₃ for forming protective layer on the side wall of said trench.

2. A composite gas as set forth in claim 1, wherein said base composite gas is selected among SiCl ₄ /N₂ type gas, Cl ₂ /N₂ type gas, Cl ₂ /O₂ type gas, Br₂ /N₂ type gas, HBr/N₂ type gas, SiCl ₄ /O₂ type gas.

3. A composite gas as set forth in claim 1, wherein said additive gas is added to the base composite gas in a range of 1 to 90%.

4. A dry etching process for forming a trench in a monocrystalline silicon, comprising the steps of:

forming an opening in SiO₂ layer formed on a monocrystalline silicon according to a desired etching pattern;

performing etching with utilizing residual SiO₂ layer as a masking layer and with an etching gas, which is composed of;

a base composite gas for etching the monocrystalline silicon; and

an additive gas added to said base composite gas, said additive gas containing at least Cl F₃ for forming protective layer on the side wall of said trench.

5. A dry etching process as set forth in claim 4, wherein said base composite gas is selected among SiCl ₄ /N₂ type gas, Cl ₂ /N₂ type gas, Cl ₂ /O₂ type gas, Br₂ /N₂ type gas, HBr/N₂ type gas, SiCl ₄ /O₂ type gas.

6. A dry etching process as set forth in claim 4, wherein said additive gas is added to the base composite gas in a range of 1 to 90%.