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Mask for Excimer Laser Ablation And Method of Producing Same

IP.com Disclosure Number: IPCOM000100897D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 76K

Publishing Venue

IBM

Related People

Tam, A: AUTHOR [+3]

Abstract

The mask is a stencil mask containing the mask pattern as physical holes in a thin silicon (Si) membrane. The membrane is stretched between a frame which is a section of a relatively thick silicon mask. The mask is formed, with adulteration of the desired pattern through pinholes in the resist mask and particulate matter therein being eliminated by performing the photolithographic etch process twice.

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Mask for Excimer Laser Ablation And Method of Producing Same

       The mask is a stencil mask containing the mask pattern as
physical holes in a thin silicon (Si) membrane.  The membrane is
stretched between a frame which is a section of a relatively thick
silicon mask.  The mask is formed, with adulteration of the desired
pattern through pinholes in the resist mask and particulate matter
therein being eliminated by performing the photolithographic etch
process twice.

      The mask, of which a schematic top view is shown in Fig. 1A,
consists of an Si wafer 1 into which tublike recesses are etched.
These recesses are limited by edge 2 of wafer 1, Si ribs 3 and a
thin Si membrane 4 (also see Fig. 1B showing a cutout of the
cross-section through wafer 1 of Fig. 1A along line A).  Holes 5 are
etched into membrane 4.  The mask is rather stable thermally.  This
thermal stability can be increased by coating the surface of the mask
facing the laser with a multilayer reflection system (MRS) and/or the
surface of the mask facing the material to be ablated (e.g.,
polyimide) with a gold layer.

      The formation of the mask is shown in Figs. 2A to 2F which are
schematic cutouts of a cross-section of the mask at different stages
of its formation.

      Si membrane 4 is covered with SiO2 layer 6 and (positive)
resist layer 7 with a pinhole 10.  A particle 9 is positioned on
resist layer 7 (Fig. 2A).  Resist layer 7 is irradiated through a
mask (not shown) wi...