Browse Prior Art Database

Slope Formation and Its Angle Control on Etching of Aluminum Gate Film

IP.com Disclosure Number: IPCOM000112463D
Original Publication Date: 1994-May-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 4 page(s) / 69K

Publishing Venue

IBM

Related People

Kitahara, H: AUTHOR [+2]

Abstract

Disclosed is a method for Al slope etching used in process of Thin Film Transistor/Liquid Crystal Display (TFT/LCD). Required slope angle is controlled by variation of the motion of substrate, pressure of spray and mixture of etchant.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 69% of the total text.

Slope Formation and Its Angle Control on Etching of Aluminum Gate Film

      Disclosed is a method for Al slope etching used in process of
Thin Film Transistor/Liquid Crystal Display (TFT/LCD).  Required
slope angle is controlled by variation of the motion of substrate,
pressure of spray and mixture of etchant.

      Fig. 1 shows the process on slope formation of Aluminum film.
SiOx film, Aluminum (Al) film, and Molybdenum (Mo) film are deposited
onto a glass substrate, and photoresist is coated onto the films.
The layers of Mo and Al are dissolved in the etchant that is a
mixture of phosphoric acid, nitric acid, acetic acid, and water.
Calmer etching method provides higher side-etching rate of Mo than
that of Al.  As the large difference of side-etching rate of Mo and
Al, calmer etching method provides smaller degree of Al slope.

      Control of taper angle degree is also available by the rate of
the substrate motion speed and the pressure of etchant spray.  Fig. 2
shows controlling of slope angle by speed of the substrate motion,
and Fig. 3 shows controlling of slope angle by pressure of etchant
spray.  As the side etching rate of Mo and Al is changed by the speed
of etchant stirring as shown in Fig. 4 (a) (b) (c) and Fig. 5, these
two methods are compatible.

      Precise control of slope angle by the mixture of etchant is
also available.  Fig. 6 shows the dependence of slope angle on an
amount of nitric acid in the etchant.  The defect caused b...