Method for in-situ cleaning of native oxide from silicon surfaces

• US 5,899,752 A
• Filed: 04/26/1995
• Issued: 05/04/1999
• Est. Priority Date: 07/30/1993
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Carlson, David, Hey, H. Peter W
• Primary Examiner(s): Bowers, Charles
• Assistant Examiner(s): WHIPPLE, MATTHEW LAVERNE
• Application Number:
  US08/429,432
• Time in Patent Office: 1,469 Days
• Field of Search: 438/906, 438/775, 438/791
• US Class Current: 438/791
• CPC Class Codes: H01L 21/02046 Dry cleaning only H01L21/02085 takes precedence
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/3003 Hydrogenation or deuterisation, e.g. using atomic hydrogen from a plasma
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: Y10S 438/906 Cleaning of wafer as interim step

Abstract

A method of in-situ cleaning a native oxide layer from the surface of a silicon wafer positioned in a vacuum chamber that is substantially free of oxidizing species by passing at least one non-oxidizing gas over the native oxide layer at a wafer cleaning temperature between about 650° C. to about 1025° C. for a sufficient length of time until such native oxide layer is removed.

Claims

1. A method of processing a silicon wafer, the wafer having a native oxide thereon, comprising:

positioning said silicon wafer in a chemical vapor deposition chamber;

evacuating said chamber until the chamber pressure is less than about 10^-5 Torr of oxygen and water;

flowing hydrogen and at least one other reducing gas selected from the group consisting of silane and dichlorosilane over the surface of said silicon wafer;

thereafter, heating said silicon wafer to a wafer cleaning temperature of not higher than about 1025°

C. while continuing to flow hydrogen over the surface of said silicon wafer until an evaporation and a chemical reaction remove substantially all native oxide from the surface of the silicon wafer; and

then forming a layer of silicon nitride on the surface of said silicon wafer without removing the wafer from said chamber by passing a mixture of dichlorosilane gas and ammonia gas over the surface of said silicon wafer at a deposition temperature not higher than said wafer cleaning temperature.

2. A method according to claim 1 further comprising, after the step of removing the native oxide, reducing the temperature within said chamber to a deposition temperature in the range between about 700°

C. to 800°

C.

3. A method according to claim 1 wherein said native oxide is removed within no more than 1 minute.

4. A method according to claim 1 wherein said wafer cleaning temperature is in the range between 700°

C. to 840°

C.

5. A method according to claim 1, wherein said wafer cleaning temperature is preferably in the range between about 800°

C. to about 1025°

C.