High-pressure anneal process for integrated circuits

• US 6,693,048 B2
• Filed: 03/05/2002
• Issued: 02/17/2004
• Est. Priority Date: 01/22/1996
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Lane, Richard H., Wald, Phillip G.
• Primary Examiner(s): Cuneo, Kamand
• Assistant Examiner(s): KILDAY, LISA A
• Application Number:
  US10/091,936
• Publication Number:
  US 20020098715A1
• Time in Patent Office: 714 Days
• Field of Search: 438/660, 438/775, 438/791, 438/795, 438/904, 257/292
• US Class Current: 438/775
• 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 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/28176 with a treatment, e.g. annealing, after the formation of the definitive gate conductor
• CPC Class Codes: H01L 21/28185 with a treatment, e.g. annealing, after the formation of the gate insulator and before the formation of the definitive gate conductor
• CPC Class Codes: H01L 21/28194 by deposition, e.g. evaporation, ALD, CVD, sputtering, laser deposition H01L21/28202 takes precedence
• CPC Class Codes: H01L 21/28202 in a nitrogen-containing ambient, e.g. nitride deposition, growth, oxynitridation, NH3 nitridation, N2O oxidation, thermal nitridation, RTN, plasma nitridation, RPN
• CPC Class Codes: H01L 21/324 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/20 - H01L21/288 and H01L21/302 - H01L21/322 take precedence
• CPC Class Codes: H01L 29/513 the variation being perpendicular to the channel plane
• CPC Class Codes: H01L 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material
• CPC Class Codes: Y10S 438/904 Charge carrier lifetime control
• CPC Class Codes: Y10S 438/908 Utilizing cluster apparatus

Abstract

This invention embodies an improved process for annealing integrated circuits to repair fabrication-induced damage. An integrated circuit is annealed in a pressurized sealed chamber in which a forming gas comprising hydrogen is present. Pressurization of the chamber reduces the contribution made by the final anneal step to total thermal exposure by increasing the diffusion rate of the hydrogen into the materials from which the integrated circuit is fabricated. Ideally, the forming gas contains, in addition to hydrogen, at least one other gas such as nitrogen or argon that will not react with hydrogen and, thus, reduces the danger of explosion. However, the integrated circuit may be annealed in an ambiance containing only hydrogen gas that is maintained at a pressure greater than ambient atmospheric pressure.

Claims

1. A processing method for a workpiece of semiconductor material, said workpiece having at least one transistor gate structure having at least one first film of silicon nitride and having a second silicon nitride film deposited as a layer over at least a portion of said workpiece, comprising:

placing said workpiece in a region having an ambient pressure of a gas, said workpiece having at least one trransisitor gate structure having at least one first film of silicon nitride and having a second silicon nitride film deposited as a layer over at least a portion of said workpiece;

providing a forming gas in said region; and

annealing said workpiece within said region in said forming gas, a pressure of said forming gas being greater than said ambient pressure of said gas in said region, said workpiece having at least one transistor gate structure having at least one first film of silicon nitride and having a second silicon nitride film deposited as a layer over at least a portion of said workpiece.

2. The method in claim 1, wherein said annealing said workpiece comprises annealing said workpiece in said forming gas at a pressure greater than one atmosphere.

3. The method in claim 2, wherein said annealing said workpiece comprises annealing said workpiece in said forming gas at a pressure ranging from about 10 atmospheres to about 25 atmospheres.

4. A processing method for treating a workpiece of semiconductor material, said workpiece having an integrated circuit having at least one transistor gate structure having a first film of silicon nitride as at least one side wall spacer and having a capping layer on a portion thereof and having a silicon nitride film deposited as a final layer over a portion of said workpiece, comprising:

providing a chamber in an environment that surrounds said chamber;

placing said integrated circuit in said chamber, said integrated circuit having at least one transistor gate structure having a first film of silicon nitride as at least one side wall spacer and having a capping layer on a portion thereof and having a silicon nitride film deposited as a final layer over a portion of said integrated circuit;

introducing into said chamber a generally non-oxidizing atmosphere comprising hydrogen; and

generating a first pressure inside said chamber, said first pressure being greater than a second pressure of said environment that surrounds said chamber.

5. The method in claim 4, wherein said generating a first pressure comprises generating a first pressure greater than a general atmospheric pressure.