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US4767723A Expired / Lapsed US ⏱️ 0.0 years remaining

Process for making self-aligning thin film transistors

Assignee: AUO Corp
•
Filing: 1987-10-30
•
Granted: 1988-08-30
•
Expires: 2007-10-30
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Abstract

Abstract A process for making a self-aligned thin film transistor, said process comprising the steps of: (1) providing a gate which comprises a glass substrate, a transparent electrode on top thereof, and a metal electrode on top of said transparent electrode, (2) forming a stack by depositing over said gate a triple layer structure consisting of gate dielectric material, active material and a top passivating dielectric, (3) coating the top of said triple layer with a dual-tone photoresist, (4) exposing said photoresist from the top through a mask having transparent areas, opaque areas and areas transparent to selective wavelengths, using broad band UV light, (5) developing the photoresist by treatment with a solvent, (6) etching the stack with a liquid etchant through to the glass substrate, (7) exposing the photoresist from the bottom through the glass substrate using near UV light, (8) developing the photoresist with a solvent, and (9) etching off the top passivating layer of the stack.

Inventors

  • 👤 William D. Hinsberg, III
  • 👤 Webster E. Howard
  • 👤 Carlton G. Willson

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-26 02:29
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/004; G03F7/09; G03F7/095; H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/031; H10D30/0312; H10D30/0316; H10D30/0321; H10D30/60; H10D30/67; H10D30/6729; H10D30/673; H10D30/6737; H10D30/6739; H10P; H10P76/00; H10P76/20; H10P76/204; H10P76/2041; Y; Y10; Y10S; Y10S148/00; Y10S148/137; Y10S438/00; Y10S438/928

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 157 words
A process for making a self-aligned thin film transistor, said process comprising the steps of: (1) providing a gate which comprises a glass substrate, a transparent electrode on top thereof, and a metal electrode on top of said transparent electrode, (2) forming a stack by depositing over said gate a triple layer structure consisting of gate dielectric material, active material and a top passivating dielectric, (3) coating the top of said triple layer with a dual-tone photoresist, (4) exposing said photoresist from the top through a mask having transparent areas, opaque areas and areas transparent to selective wavelengths, using broad band UV light, (5) developing the photoresist by treatment with a solvent, (6) etching the stack with a liquid etchant through to the glass substrate, (7) exposing the photoresist from the bottom through the glass substrate using near-UV light, (8) developing the photoresist with a solvent, and (9) etching off the top passivating layer of the stack.
Claim 2
Dependent Claim 157 words
A process for making a self-aligned thin film transistor, said process comprising the steps of: (1) providing a gate which comprises a glass substrate, a transparent electrode on top thereof, and a metal electrode on top of said transparent electrode, (2) forming a stack by depositing over said gate a triple layer structure consisting of gate dielectric material, active material and a top passivating dielectric, (3) coating the top of said triple layer with a dual-tone photoresist, (4) exposing said photoresist from the top through a mask having transparent areas, opaque areas and areas transparent to selective wavelengths, using broad band UV light, (5) developing the photoresist by treatment with a solvent, (6) etching the stack with a liquid etchant through to the glass substrate, (7) exposing the photoresist from the bottom through the glass substrate using near-UV light, (8) developing the photoresist with a solvent, and (9) etching off the top passivating layer of the stack.
Claim 3
Dependent Claim 36 words
A process as claimed in claim 1 wherein the dual-tone photoresist comprises a phenol-formaldehyde-type matrix resin, an accelerating photoactive additive which is a diazoquinone, and a decelerating photoactive additive which is a mono- or bis-aryl azide.
Claim 4
Dependent Claim 31 words
A process as claimed in claim 1 wherein the mask is a chromium-on-quartz photomask having certain transparent areas which transmit mid-UV light and other transparent areas which transmit only near-UV light.

References Cited (Backward Citations)

US4700458A Cited
EP0090661A2 Cited
DE3337315A1 Cited
US4599246A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1991-08-30 1992-02-29 1992-08-30 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1995-08-30 1996-02-29 1996-08-30 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1999-08-30 2000-02-29 2000-08-30 $7700.00 Window Closed / Lapsed

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