Wafer processing using thermal nitride etch mask

• US 5,711,891 A
• Filed: 09/20/1995
• Issued: 01/27/1998
• Est. Priority Date: 09/20/1995
• Status: Expired due to Term

• Current Assignee: Bell Semiconductor, LLC (Hilco Inc. (d/b/a Hilco Global))
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Pearce, Charles Walter
• Primary Examiner(s): Breneman, R. Bruce
• Assistant Examiner(s): ALANKO, ANITA KAREN
• Application Number:
  US08/531,115
• Time in Patent Office: 860 Days
• Field of Search: 216/2, 216/27, 216/5, 216/56, 216/99, 156/659.11
• US Class Current: 216/51
• CPC Class Codes: B41J 2/1601 Production of bubble jet print heads B41J2/1606, B41J2/162 take precedence
• CPC Class Codes: B41J 2/1629 wet etching
• CPC Class Codes: B41J 2/1631 photolithography
• CPC Class Codes: B41J 2/1642 thin film formation by CVD [chemical vapor deposition]

Abstract

A method for forming v-shaped grooves in a substrate such as a channel plate is disclosed. A mask of silicon nitride formed by a thermal nitridation process protects the substrate during KOH etching.

Claims

1. A method of wafer processing comprising:

forming a layer of silicon nitride ≦

50 angstroms thick by a thermal nitridation process upon a silicon substrate;

patterning said layer of silicon nitride to expose portions of said substrate; and

etching said exposed portions of said substrate to produce at least one v-shaped groove.

2. The method of claim 1 in which said etching process etches through said substrate.

3. The method of claim 1 in which said etching process is performed in KOH.

4. The method of claim 1 in which said thermal nitridation process comprises:

exposing said substrate to at least one of a gas chosen from the group consisting of NH₃ and N₂ at atmospheric pressure at a temperature between 900°

C. and 1200°

C.

5. The method of claim 1 in which a layer of silicon dioxide is formed on said silicon substrate prior to said forming of said layer of silicon nitride.

7. The method of claim 1 in which said layer of silicon nitride has a thickness of 50 angstroms.

6. A method of forming a channel plate comprising:

forming a layer of silicon dioxide upon a silicon wafer by exposing said wafer to an atmosphere of oxygen and hydrochloric acid at a temperature of approximately 1050°

C.;

forming a layer of silicon nitride ≦

50 angstroms thick between said layer of silicon dioxide and said silicon wafer by a thermal nitridation process which includes exposing said wafer to an atmosphere of 20% NH₃ and 80% of N₂ at approximately 1100°

C. and atmospheric pressure;

forming a material layer over said layer of silicon dioxide, said material being chosen from the group consisting of silicon nitride and polysilicon;

patterning said material layer and said layer of silicon dioxide and said layer of silicon nitride;

exposing said wafer to KOH to form two or more v-grooves;

removing said patterned material layer and said layer of silicon dioxide and said layer of silicon nitride;

sawing said wafer to form at least one channel plate.

8. The method of claim 6 in which said layer of silicon nitride has a thickness of 50 angstroms.