Browse Prior Art Database

Four-Step, Fine-Line, Thin-Film Substrate

IP.com Disclosure Number: IPCOM000101618D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Horwath, R: AUTHOR [+4]

Abstract

Over the past several years, laser direct writing has been used to repair circuit lines in packages. It might appear that this technique could be used to write the entire personality on the substrate. However, the laser energies required to write an entire substrate with line thickness greater than .1 u are prohibitive.

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Four-Step, Fine-Line, Thin-Film Substrate

       Over the past several years, laser direct writing has
been used to repair circuit lines in packages.  It might appear that
this technique could be used to write the entire personality on the
substrate.  However, the laser energies required to write an entire
substrate with line thickness greater than .1 u are prohibitive.

      This proposal is to use laser ablation and laser direct writing
to produce a low-cost, very fine-line substrate for thin film
electronic packages (those containing dielectrics).  The process
steps are:
   1)   Laser ablate pattern in dielectric film 8u deep 1 mil if
required).  See Fig. 1.
      2)   Laser direct write personality seed in trenches. This can
be done with or without mask, vapor or solid phase technique.  See
Fig. 2.
      3)   Fast additive or acid Cu Plate (several thousand at a
time). See Fig. 3.
      4)   Test inspect - The partial ablation of the polyimide forms
a trench into which the seed layer is deposited. The plating will
then conform to the walls of the trench allowing for finer lines than
would be available with the isotropic plating processes.

      Reference: F. A. House, C. R. Jones, T. H. Baum, C. Pico and G.
A. Kovac, Appl .  Phys . Lett 46, 204 (1985).