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US5035768A Expired / Lapsed US ⏱️ 0.0 years remaining

Novel etch back process for tungsten contact/via filling

Assignee: Intel Corp
•
Filing: 1990-07-30
•
Granted: 1991-07-30
•
Expires: 2010-07-30
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Abstract

Abstract An etchback process for etching a refractory metal layer formed on a semiconductor substrate with a greatly reduced micro-loading effect. The etch proceeds in three steps. The first step is a uniform etch which utilizes a gas chemistry of SF 6 , O 2 and He and proceeds for a predetermined time to remove most of the metal layer. The second step is a very uniform etch which utilizes a gas chemistry of SF 6 , Cl 2 and He and proceeds until the endpoint is detected. The endpoint is detected by measurement and integration of the 772 nm and 775 nm lines of Cl. The third step is a timed etch utilizing a gas chemistry of Cl 2 and He which is used as both an overetch to ensure complete removal of the refractory metal film and as a selective etchant to remove an adhesion underlayer.

Inventors

  • 👤 Xiao-Chun Mu
  • 👤 Jagir Multani

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 21:54
CPC Classifications
C; C23; C23F; C23F4/00; H; H10; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/062

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 49 words
In a process for etching a refractory metal, said process utilizing a chlorine containing gas, an improvement comprising the detection of the endpoint of said etch by the measurement and integration of emission lines of chlorine, said lines comprising the 772 nm and 775 nm emission lines of chlorine.
Claim 2
Dependent Claim 49 words
In a process for etching a refractory metal, said process utilizing a chlorine containing gas, an improvement comprising the detection of the endpoint of said etch by the measurement and integration of emission lines of chlorine, said lines comprising the 772 nm and 775 nm emission lines of chlorine.
Claim 3
Dependent Claim 41 words
In a process for etching a refractory metal, an improvement wherein the gas mixture is comprised of SF 6 , Cl 2 , and He, and the pressure of said gas mixture is in the range of approximately 600-800 m Torr.
Claim 4
Dependent Claim 41 words
In a process for etching a refractory metal, an improvement wherein the gas mixture is comprised of SF 6 , Cl 2 , and He, and the pressure of said gas mixture is in the range of approximately 600-800 m Torr.
Claim 5
Dependent Claim 72 words
In a process for etching a refractory metal, an improvement wherein the gas mixture is comprised of SF 6 , Cl 2 , and He, the pressure of said gas mixture is in the range of approximately 600-800 mTorr, and the detection of the endpoint of said etch is by the measurement and integration of emission lines of chlorine, said lines comprising the 772 nm and 775 nm emission lines of chlorine.
Claim 6
Dependent Claim 72 words
In a process for etching a refractory metal, an improvement wherein the gas mixture is comprised of SF 6 , Cl 2 , and He, the pressure of said gas mixture is in the range of approximately 600-800 mTorr, and the detection of the endpoint of said etch is by the measurement and integration of emission lines of chlorine, said lines comprising the 772 nm and 775 nm emission lines of chlorine.
Claim 7
Dependent Claim 15 words
The process described in claim 1, 2, 3 wherein said refractory metal is Tungsten (W).

References Cited (Backward Citations)

JPS5563830A Cited
US4502913A Cited
US4713141A Cited
US4786360A Cited
US4936950A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1994-07-29 1995-01-28 1995-07-30 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1998-07-29 1999-01-28 1999-07-30 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2002-07-29 2003-01-28 2003-07-30 $7700.00 Window Closed / Lapsed

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