Browse Prior Art Database

Direct Patterning with a Pulsed Deposition Source

IP.com Disclosure Number: IPCOM000108945D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 2 page(s) / 91K

Publishing Venue

IBM

Related People

Cuomo, JJ: AUTHOR [+2]

Abstract

A previously patented class of "direct patterning" schemes (*) produces patterned thin films by continuous deposition concurrent with spatially selective removal by a repetitive pulsed lift-off process. Disclosed here is an improved direct patterning scheme which utilizes a pulsed deposition source. This allows deposition to occur between lift-off pulses, thus avoiding film contamination by gaseous lift-off products.

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Direct Patterning with a Pulsed Deposition Source

       A previously patented class of "direct patterning"
schemes (*) produces patterned thin films by continuous deposition
concurrent with spatially selective removal by a repetitive pulsed
lift-off process.  Disclosed here is an improved direct patterning
scheme which utilizes a pulsed deposition source. This allows
deposition to occur between lift-off pulses, thus avoiding film
contamination by gaseous lift-off products.

      In the previously patented direct patterning schemes, patterned
films of a desired material are produced by a continuous deposition
concurrent with spatially selective removal.  Material removal is
accomplished by using pulsed laser irradiation to repetitively
vaporize the top surface layer of an underlying lift-off mask.  The
lift-off mask is typically a polymer film.  The case of a
pre-patterned lift-off mask with blanket laser irradiation is
illustrated in the figure at four process stages: (a) prior to
deposition, (b) early in the deposition, (c) immediately after a
laser-lift-off pulse, and (d) at completion.  Alternatively, the
lift-off mask can be a blanket polymer film, in which case selective
lift-off would be provided by patterned laser irradiation.

      These schemes have the dual advantages of being "dry" and
requiring a reduced number of processing steps, and may be useful for
producing patterned thin films for microelectronic circuitry and
other applications. The use of a pulsed deposition source removes a
major disadvantage of the previous process, i.e., poor metal quality
due to incorporation of contaminants from the pressure spikes
generated during polymer mask ablation.

      "Pulsed Laser Deposition" (PLD) is one example of a pulsed
deposition source suitable for the present application.  In PLD, a
target of the material to be deposited is repetitively irradiated
with the focussed output of a pulsed laser (at typical power
densities of ~108 W/cm2 or ~ 2 J/cm2 for a 20 ns pulse).  The
vaporized target mater...