Silicidation process with etch stop

• US 5,698,468 A
• Filed: 06/07/1995
• Issued: 12/16/1997
• Est. Priority Date: 06/07/1995
• Status: Expired due to Term

• Current Assignee: Bell Semiconductor, LLC (Hilco Inc. (d/b/a Hilco Global))
• Original Assignee: LSI Logic Corporation (Broadcom, Inc.)
• Inventors: Kapoor, Ashok K.
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): Turner, Kevin F.
• Application Number:
  US08/486,803
• Time in Patent Office: 923 Days
• Field of Search: 437/192, 437/200, 437/228 ES, 437/247
• US Class Current: 438/664
• CPC Class Codes: H01L 21/02186 the material containing titanium, e.g. TiO2
• CPC Class Codes: H01L 21/02244 of a metallic layer
• CPC Class Codes: H01L 21/02255 formation by thermal treatment H01L21/02252 takes precedence; after treatment of an insulating film H01L21/3105 and subgroups
• CPC Class Codes: H01L 21/3165 formed by oxidation H01L21/31691, H01L21/31695 take precedence
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 24/11 Manufacturing methods for bumps on insulating substrates H01L21/4853
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01022 Titanium [Ti]
• CPC Class Codes: H01L 2924/01027 Cobalt [Co]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/0104 Zirconium [Zr]
• CPC Class Codes: H01L 2924/01042 Molybdenum [Mo]
• CPC Class Codes: H01L 2924/01046 Palladium [Pd]
• CPC Class Codes: H01L 2924/01072 Hafnium [Hf]
• CPC Class Codes: H01L 2924/01073 Tantalum [Ta]
• CPC Class Codes: H01L 2924/01074 Tungsten [W]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01082 Lead [Pb]
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: Y10S 438/97 Specified etch stop material

Abstract

A semiconductor processing method forms etch stop layers over semiconductor structures without the need for additional etching, masking, and deposition steps. A refractory metal capable of forming silicides and oxides under standard processing conditions is deposited over the deposition, oxide, and polysilicon layers of a MOS integrated circuit wafer. The coated wafer is first annealed to form refractory metal silicide layers over the unoxidized silicon structures. The coated wafer is then oxidized to convert unreacted refractory metal over the oxidized silicon structures into refractory metal oxide etch stops over these structures.

Claims

1. A method for forming an etch-stop during the processing of an integrated circuit subsequent to the formation of polysilicon gate, source, drain, polysilicon interconnect, gate oxide, and field oxide regions, the method comprising:

depositing a silicide-forming refractory metal over a semiconductor structure including polysilicon gate, source, drain, polysilicon interconnect, gate oxide, and field oxide regions to form a coated structure, the deposited refractory metal contacting previously exposed surfaces of the gate, interconnect, and field oxide regions;

annealing the coated structure to form a silicided structure having refractory metal-silicide layers in contact with the previously exposed surfaces of the gate and interconnect regions; and

after the step of annealing the coated structure, oxidizing the silicided structure to form refractory metal oxide layers in contact with the previously exposed surfaces of the field oxide region, whereby the refractory metal oxide layers act as etch-stops which protect the field oxide regions during the processing of the integrated circuit.

2. The method of claim 1, wherein the depositing step is a chemical vapor deposition step.

3. The method of claim 1, wherein the depositing step is a sputter deposition step.

4. The method of claim 1, wherein the depositing step is an electron beam deposition step.

5. The method of claim 1, wherein the depositing step is an evaporation deposition step.

6. The method of claim 1, wherein the annealing step comprises heating the coated structure to between approximately 600°

C. and 800°

C. for between approximately 10 seconds and 60 seconds.

7. The method of claim 5, wherein the oxidizing step comprises the substeps of:

heating the coated structure to between approximately 400°

C. and 900°

C.; and

exposing the heated, coated structure to an oxidizing agent.

8. The method of claim 1, wherein the depositing step comprises depositing a silicide-forming refractory metal selected from the group consisting of:

cobalt, hafnium, molybdenum, nickel, palladium, platinum, tantalum, titanium, tungsten, and zirconium.

9. The method of claim 7, wherein the silicide-forming refractory metal is titanium.

10. The method of claim 7, wherein the oxidizing agent is oxygen.