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Taper Angle Control for Molybdenum Etching

IP.com Disclosure Number: IPCOM000123062D
Original Publication Date: 1998-May-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 86K

Publishing Venue

IBM

Related People

Arai, T: AUTHOR [+2]

Abstract

Disclosed is a method to control the angle of tapered edge of the olybdenum (Mo), which is etched by a wet solution. Reactive sputtered molybdenum oxide (MoOx) or molybdenum nitride (MoNy) film is formed on or beneath the molybdenum film. According to this method, tapered Mo-edge is formed, and the short-circuit defects caused by the inferior step coverage of subsequent CVD films can be reduced on the fabrication of active matrix liquid crystal displays (AMLCDs).

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Taper Angle Control for Molybdenum Etching

   Disclosed is a method to control the angle of tapered
edge of the olybdenum (Mo), which is etched by a wet solution.
Reactive sputtered molybdenum oxide (MoOx) or molybdenum nitride
(MoNy) film is formed on or beneath the molybdenum film.  According
to this method, tapered Mo-edge is formed, and the short-circuit
defects caused by the inferior step coverage of subsequent CVD films
can be reduced on the fabrication of active matrix liquid crystal
displays (AMLCDs).

   Mo is widely used for electrodes because of its low
resistivity and superior patternability.  The formation of a tapered
edge is important to ensure adequate coverage by the CVD insulators
and subsequent metal layers (Figure 1).  A tapered edge is formed by
using the difference of the etching rate between Mo and reacted Mo
(MoOx, MoNy, UU tc.).  The multi-layered film such as Mo/MoOx can be
obtained by using only one sputtering target and two sputtering
gasses (Ar and O2, ...etc.).

   Figure 2 shows the formation of a tapered edge.  MoOx is
formed on the Mo film by a reactive sputtering method.  This
double-layere d film is etched by a wet etchant like a mixture of
phosphoric acid, nitric acid, and acetic acid.  The edge of the Mo
becomes taper- shape due to the difference of the etching rate
between Mo and MoOx.  The angle of the tapered Mo can be controlled
by controlling oxidation rate of MoOx.  The oxidation rate of the
MoOx can be controlled by ch...