Etch stop useful in avoiding substrate pitting with poly buffered locos
AssigneeMicron Semiconductor, Inc.
InventorJ. Brett Rolfson
Life of this patent
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Abstract
Active regions on a semiconductor substrate are isolated, whereby an Oxide/Nitride/Oxide sandwich is disposed on a substrate, and a polysilicon layer and a nitride layer are also disposed thereon. The Oxide/Nitride/Oxide sandwich substantially inhibits "pitting" of the substrate when the polysilicon layer is removed. Method of preventing "pitting" of an underlying substrate through the use of a nitride (or other HF-resistant material) disposed beneath the polysilicon layer of a Poly Buffered LOCOS stack.
Claims21
A method for preventing substrate damage during semiconductor fabrication, said method comprising the following steps of:
- creating a first oxide layer on a semiconductor substrate;
- depositing a resistant layer superjacent said first oxide layer;
- re-oxidizing said resistant layer;
- depositing a polysilicon layer superjacent said re-oxidized layer;
- depositing a material which inhibits oxidation of said polysilicon layer superjacent said polysilicon layer, said layers forming a stack;
- patterning said stack to create designated areas, said areas having a periphery;
- anisotropically etching all of said layers of said stack outside of said periphery;
- and
- oxidizing outside of said periphery.
A process for isolating active areas on a semiconductor substrate, said process comprising the following steps of:
- creating an oxide/nitride/oxide sandwich on a semiconductor substrate using thermal re-oxidation;
- disposing a buffer layer superjacent said sandwich;
- disposing a nitride layer superjacent said buffer layer;
- masking said nitride layer, said nitride layer having masked portions and unmasked portions;
- anisotropically etching said unmasked portions of said nitride layer through said buffer layer and said sandwich;
- and
- oxidizing said substrate.
A process for manufacture of semiconductors, said process comprising the following steps of:
- creating a pad oxide superjacent a semiconductor substrate;
- disposing a first nitride layer superjacent said pad oxide;
- re-oxidizing said first nitride layer;
- disposing a buffer layer superjacent said re-oxidizing nitride layer;
- disposing a second nitride layer superjacent said buffer layer;
- said layers forming a stack;
- patterning said stack of layers, thereby creating patterned and unpatterned portions;
- and
- anisotropically etching all of said layers of said stack in said unpatterned portions, thereby exposing said pad oxide.
Dependencies are inferred from the claim text.