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Sic Replica Technique for Investigating Deep Trenches

IP.com Disclosure Number: IPCOM000099714D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 1 page(s) / 34K

Publishing Venue

IBM

Related People

Bartha, J: AUTHOR [+4]

Abstract

Memory chips operating with a capacitor vertically aligned to the chip surface are produced by introducing a deep and narrow trench in the chip surface, followed by coating the trench surface with a thin dielectric and filling the trench with a conductive electrode. Such deep trenches may also be used as isolation trenches for bipolar logic chips.

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Sic Replica Technique for Investigating Deep Trenches

       Memory chips operating with a capacitor vertically
aligned to the chip surface are produced by introducing a deep and
narrow trench in the chip surface, followed by coating the trench
surface with a thin dielectric and filling the trench with a
conductive electrode.  Such deep trenches may also be used as
isolation trenches for bipolar logic chips.

      For both applications it is essential to know the depth,
profile and defects of the trenches formed by reactive ion etching.
Therefore, it is proposed that the trenches be coated with a thin
layer of inorganic material produced by PECVD (plasma enhanced
chemical vapor deposition) and that part of the wafer be removed by
wet etching through a SiO2 window from the back of the wafer down to
the resistant layer of inorganic material (typically, several mm2).

      The thin PECVD film used to produce the imprint of the deep
trenches must meet at least the following requirements: 1) it must be
highly resistant to wet etching and 2) it must be tensile stressed to
prevent warping of the bared imprint.

                            (Image Omitted)

      This allows the deep RIE produced structures, even if they are
underetched, to be used as replica, say, to reproduce holes as
pillars.  The described replica technique is suitable for reproducing
structural details < 0.1mm.

      The materials of the replica layer may be,...