Browse Prior Art Database

Low-Fluence Laser Patterning of Diamond Films

IP.com Disclosure Number: IPCOM000104411D
Original Publication Date: 1993-Apr-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 119K

Publishing Venue

IBM

Related People

Saenger, KL: AUTHOR [+2]

Abstract

The post-growth patterning of crystalline diamond films is often slow and cumbersome due to sample masking requirements and the low etch rates of the currently available patterning processes. For example, ion beam (IB) etching of mono- or poly-crystalline diamond films with Ar or H sub 2 provides etch rates of only 10-40 A/min and typically requires the deposition, patterning, and eventual removal of a contact mask (usually photoresist).

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Low-Fluence Laser Patterning of Diamond Films

      The  post-growth  patterning of crystalline diamond films is
often slow and cumbersome due to sample masking requirements and the
low etch rates of the currently available patterning processes.  For
example, ion beam (IB) etching of  mono-  or poly-crystalline diamond
films with Ar or H sub 2 provides etch rates of only 10-40
A/min  and typically requires the deposition, patterning,
and eventual removal of a contact  mask  (usually  photoresist).

Disclosed is a  simple, high-rate, low-fluence laser patterning
technique that provides diamond-film  etching  in the  illuminated
areas  without  damage  to  the underlying substrate.

      The disclosed process is  based  on  the  finding  that
polycrystalline  diamond  films on silicon substrates can be etched
by pulsed UV laser irradiation at fluences below both that required
to etch single crystal diamond [*] and that required to etch or
damage the underlying substrate.  Film etching takes place only in
the laser-illuminated area, which may be delineated by means  of a
projection or contact mask.

      The disclosed patterning technique was demonstrated (in an  air
ambient)  on polycrystalline diamond films grown on silicon wafers
by  both  filament-assisted  chemical  vapor deposition  and
plasma-enhanced  chemical  vapor deposition (PECVD), and on similar
boron-doped polycrystalline  diamond films  deposited  by PECVD.
Approximately 2 to 20 pulses of KrF excimer laser light (&lambda.=
248 nm, pulse length = 30 ns) at a fluence of &approx.0.5 - 1.1 J/cm
sup 2 were required to remove films of 1 - 2 &mu.m in thickness.
This corresponds to a maximum etch time of ~2 min for a 5"
diameter wafer (assuming a laser operated at 0.5 J/pulse and a
repetition rate of...