Etching material and etching method

• US 5,976,988 A
• Filed: 04/26/1996
• Issued: 11/02/1999
• Est. Priority Date: 04/26/1995
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Uehara, Yukiko, Sugawara, Akira, Konuma, Toshimitsu, Murakami, Satoshi, Nishi, Takeshi, Nakazawa, Misako
• Primary Examiner(s): Breneman, R. Bruce
• Assistant Examiner(s): ALANKO, ANITA KAREN
• Application Number:
  US08/638,119
• Time in Patent Office: 1,285 Days
• Field of Search: 438/745, 438/756, 216/101, 216/104, 216/109, 252/79.3, 252/79.4
• US Class Current: 438/745
• CPC Class Codes: C09K 13/08 containing a fluorine compound
• CPC Class Codes: H01L 21/31111 by chemical means

Abstract

An alumina film, a silicon oxide film, and a silicon nitride film formed on a substrate containing a large amount of alumina are etched by using an etching material in which the concentration of ammonium fluoride, which is a component of BHF, is set low. Etching is performed by using an etching material that is an aqueous solution produced by mixing hydrofluoric acid, ammonium fluoride and water at a weight ratio of x:y:(100-x-y) where x and y satisfy a relationship y<-2x+10 (0<x≦5, 0<y≦10). 50% hydrofluoric acid on the market and 40% aqueous solution of ammonium fluoride are used.

Claims

1. An etching material for removing an insulating film comprising aluminum oxide formed on wiring provided on a substrate, comprising:

an aqueous solution containing at least hydrofluoric acid at 0.49 to 2.0 weight % and ammonium fluoride at 0.19 to 2.0 weight %.

2. The material of claim 1 wherein the aqueous solution contains hydrofluoric acid, ammonium fluoride, and pure water at a volume ratio of n:

n;

100 where n is 0.5 to 5.

3. The material of claim 1 wherein the aqueous solution contains a surface active agent.

4. An etching method comprising the steps of:

forming an aluminum oxide layer on a surface of a material containing aluminum;

preparing an etching material comprising an aqueous solution containing at least hydrofluoric acid and ammonium fluoride at 0.49 to 2.0 weight % and 0.19 to 2.0 weight %, respectively; and

etching the aluminum oxide layer using the etching material.

5. The method of claim 4 wherein the aqueous solution contains hydrofluoric acid, ammonium fluoride, and pure water at a volume ratio of n:

n;

100 where n is 0.5 to 5.

6. The method of claim 4 wherein the aqueous solution contains a surface active agent.

7. An etching material for removing an insulating film formed on wiring provided on a substrate, which includes aluminum oxide, comprising:

an aqueous solution containing hydrofluoric acid, ammonium fluoride and water at a weight ratio of x;

y;

(100-x-y) where x and y satisfy a relationship

space="preserve" listing-type="equation">y<

-2x+10(0<

x≦

5, 0<

y≦

10).

8. The material of claim 7 wherein the aqueous solution contains a surface active agent.

9. An etching method comprising the steps of:

forming a material containing aluminum on a substrate containing aluminum oxide;

forming an aluminum oxide layer on a surface of the material containing aluminum;

preparing an etching material comprising an aqueous solution containing at least hydrofluoric acid and ammonium fluoride at 0.49 to 2.0 weight % and 0.19 to 2.0 weight %, respectively; and

etching the aluminum oxide layer using the etching material.

10. The method of claim 9 wherein the aqueous solution contains a surface active agent.

11. A method of manufacturing an electronic device comprising:

forming a wiring comprising aluminum formed over a substrate;

oxidizing a surface of said wiring to form an aluminum oxide film on said surface to form an oxidizing surface;

providing a photoresist mask over the wiring having the oxidized surface wherein a portion of the oxidized surface is exposed from said photoresist mask; and

removing a portion of the aluminum oxide film in accordance with the photoresist mask by using an aqueous solution containing hydrofluoric acid at 0.49 to 2.0 weight percent and ammonium fluoride at 0.19 to 2.0 weight percent.

12. A method according to claim 11 wherein said substrate contains aluminum oxide.