Browse Prior Art Database

Dry Patterning Process for Diamond-Particle Seed Layers

IP.com Disclosure Number: IPCOM000104305D
Original Publication Date: 1993-Apr-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 4 page(s) / 111K

Publishing Venue

IBM

Related People

Guarnieri, CR: AUTHOR [+2]

Abstract

Conventional methods for crystalline diamond film deposition involve some form of "seeding." Typically seeding is performed by depositing a uniform layer of fine diamond particles (of diameter &tilde 0.1 - 1 &mu.m ) on the substrate surface by aerosol spray [1] or electrophoresis [2]. Patterning of this seed layer by any wet process is difficult, since any liquid on the substrate surface would allow the seed particles remaining on the surface to migrate and agglomorate. Alternative methods for patterned diamond growth by selective seeding are also difficult.

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Dry Patterning Process for Diamond-Particle Seed Layers

      Conventional methods for crystalline diamond film deposition
involve   some  form  of  "seeding."  Typically  seeding  is
performed by depositing a  uniform  layer  of  fine  diamond
particles (of diameter &tilde 0.1 - 1 &mu.m ) on the substrate
surface by aerosol spray [1] or electrophoresis [2].  Patterning  of
this  seed  layer  by  any  wet  process  is difficult, since any
liquid on the substrate  surface  would allow the seed particles
remaining on the surface to migrate and  agglomorate.  Alternative
methods for patterned diamond growth by selective seeding are also
difficult.  For example [3] selective seeding can also be performed
by first  uniformly scratching  the  entire  silicon  wafer surface
with diamond dust and then selectively "erasing" the seeding by ion
beam etching the portions of the wafer which are not protected by a
photoresist  mask  (which must be applied, patterned, and removed
prior to the diamond deposition).

      Disclosed is a simple, dry process for the selected-area
removal  of  blanket-deposited  diamond  seed particles which enables
the production of PATTERNED  diamond films  with  conventional
deposition methods such as plasma enhanced chemical vapor deposition
(PECVD).  It is based  on the  finding that diamond seed particles
can be removed from the surface of a silicon substrate by pulsed UV
laser irradiation  at  fluences  below  that  required to etch or
damage the substrate.  The disclosed seed layer patterning process
consists of:

o   UV laser irradiation delivered to the sample with a fluence (or
    power) above the threshold for particle removal, but below the
    threshold for substrate damage, and
o   a projection or contact mask to restrict the irradiation to the
    area from which the diamond particles are to be removed.

      The  disclosed  seed patterning process was implemented in an
air ambient on diamond-seeded silicon wafers coated by either an
aerosol spray method [1] or an electrophoresis method [2].
Approximately 1 to 3 pulses of KrF excimer laser light ( A
= 248 nm, pulse length = 30 ns) at a fluence of &app.  0.5 - 1.2 J/cm
sup 2 were  required  to  remove  the  seed  particles  from  the
illuminated  area.  This corresponds to a maximum patternin...