Browse Prior Art Database

Integrated Circuit and IC Package Metal Spray Process

IP.com Disclosure Number: IPCOM000101751D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

Leas, JM: AUTHOR

Abstract

Disclosed is a technique of spraying metal through a nozzle, which may have multiple orifices, to form 1 mil or wider metal lines on semiconductor chips, chip packages, or printed wiring boards without the need for masking or etching.

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This is the abbreviated version, containing approximately 52% of the total text.

Integrated Circuit and IC Package Metal Spray Process

       Disclosed is a technique of spraying metal through a
nozzle, which may have multiple orifices, to form 1 mil or wider
metal lines on semiconductor chips, chip packages, or printed wiring
boards without the need for masking or etching.

      The technique is somewhat similar to ink jet printing except
molten metal is used instead of ink.  It is also similar to a process
for forming metal lines on solar cells [*].  To form the metal lines,
molten metal is forced through an orifice or an array of orifices by
use of gas pressure.  The orifice is vibrated to break up the molten
metal stream into fine metal droplets of uniform size.  The droplets
are allowed to fall onto the required locations of the substrate
aligned beneath the nozzle to build up metal layers of increasing
thickness.

      Metals such as aluminum, copper, aluminum-silicon, or
aluminum-copper can be used.  Because the metal is deposited only in
the desired pattern, noble metals, such as gold, platinum, and
palladium can be deposited at significantly lower cost than by such
processes as evaporation or sputtering, and which require separate
patterning steps.  A wider range of patterns may be formed than by
electroplating and a wider range of materials deposited than by
electroless plating.

      The size of each metal droplet is controlled by the orifice
diameter, the gas pressure, the viscosity of the molten metal, and
the frequency of the mechanical vibration that is applied to the
nozzle.

      The metal droplets are not further dispersed by any stream of
gas, as in standard metal spray tools.  Instead, each stream of metal
droplets travels undisturbed to the target.

      The droplets may be charged as they leave the orifice and
deflected by an electric field.  Droplets may deflected along a line
or into a reservoir by the field.  The substra...