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Liquid Etch Stopper

IP.com Disclosure Number: IPCOM000116628D
Original Publication Date: 1995-Oct-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 92K

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Bartha, J: AUTHOR [+3]


Disclosed is an etch stopper for the improved fabrication of through holes by means of reactive ion etching.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Liquid Etch Stopper

      Disclosed is an etch stopper for the improved fabrication of
through holes by means of reactive ion etching.

      For micromechanics as well as packaging (including
optoelectronic packaging) through holes through flat parallel plates
are of importance.  For example, guide plates for contact beams are
used in micromechanically manufactured contact probes.  The through
holes in such plates have, for several reasons, been manufactured up
to now by sequentially etching from both sides.  The achievable
aspect ratio can thus be improved by a factor of 2.  However, etching
from both sides requires a lithographically manufactured mask on both
surfaces.  Thereby, the inlet as well as the outlet will be defined
with lithographic precision, while during the etching of very deep
through holes a tilting of the hole axis or the hole walls,
respectively, may be observed.

      When sequentially etching through holes from both sides one
half of the hole is first of all etched and after turning over the
substrate the other half is etched.  During the second etching step
the substrate has to be overetched in order to compensate exisiting
non-conformities.  However, this overetch will result in a quality
deterioration of the side walls of the first etched part of the hole.

This phenomenon can be observed when etching silicon plates as well
as plates made of plastic material.

      The method suggested here guarantees, beside the protection of
the part of the hole first etched, a very effective thermal "bonding"
of the substrat...