Browse Prior Art Database

Black Matrix Patterning

IP.com Disclosure Number: IPCOM000112434D
Original Publication Date: 1994-May-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Tsujimura, T: AUTHOR

Abstract

Disclosed is a taper etching method of germanium compounds that is used on TFT array to make black matrix layer. By making a germanium compound layer on top, whose etching rate is faster than the bottom layer, taper shape of germanium compound black matrix is available. So the reverse tilt and the reverse twist do not occur.

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Black Matrix Patterning

      Disclosed is a taper etching method of germanium compounds that
is used on TFT array to make black matrix layer.  By making a
germanium compound layer on top, whose etching rate is faster than
the bottom layer, taper shape of germanium compound black matrix is
available.  So the reverse tilt and the reverse twist do not occur.

      TFT liquid crystal display needs larger aperture ratio of TFT
array to reduce the power of backlight.  To make the TFT panel with
much larger aperture ratio, the method to make black matrix layer on
TFT is very useful.  As germanium compounds with some sputter
conditions are very black, so it is very suitable as black matrix on
TFT array.  Black matrix on TFT array must have high resistivity to
reduce the leakage current between data line and ITO, and black
matrix must have high optical density.  Adding much amount of
additive sputter gas like oxygen, nitrogen or hydrogen, the
resistivity of germanium compounds goes up and the optical density
goes down.  To make enough resistivity of germanium compounds black
matrix with enough optical density, thicker black matrix is
necessary.  But making the thickness thicker, the alignment of liquid
crystal becomes worse, so the reverse tilt or reverse twist occurs.
To reduce the reverse tilt or reverse twist, taper shape black matrix
is valid.  As shown in Fig. 1, by making two layers of germanium
compounds 2, 3 with different amount of additive sputter gas li...