Browse Prior Art Database

High Density MLC Structure

IP.com Disclosure Number: IPCOM000036406D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Arnold, AF: AUTHOR [+2]

Abstract

The process described in this article achieves reliable, inexpensive, fine-line circuitry in multi-layer ceramic (MLC) structures. By the use of a polyamide adhesive layer, copper foil may be laminated onto both sides of green sheet MLC substrate material, thereby allowing for the simultaneous creation of metal patterns on both sides of the sheet through the use of ordinary printed-circuit subtractive processing procedures.

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High Density MLC Structure

The process described in this article achieves reliable, inexpensive, fine-line circuitry in multi-layer ceramic (MLC) structures. By the use of a polyamide adhesive layer, copper foil may be laminated onto both sides of green sheet MLC substrate material, thereby allowing for the simultaneous creation of metal patterns on both sides of the sheet through the use of ordinary printed-circuit subtractive processing procedures.

An immediate advantage of the disclosed process may be found in the simplicity of processing and assembly involved, given the relatively solid physical properties of green sheet vs. film, and the capability for processing two complex patterns at once on either side of the sheet.
1) Polyamide film is first laminated to one side of

electro- formed copper foil (N0.75 to 1.0 mil thick).
2) The coated copper foil, in turn, is laminated to both

sides of the glass-ceramic green sheet. Both 1) and 2)

laminating steps may preferably be done with a standard

roller or vacuum technique.
3) Photoresist is next applied to both outer copper

surfaces, e.g., by dip or spray technique, and both sides

exposed and developed at once, using pre-aligned

photo-masters.
4) The copper is then etched in a cold solution, e.g.,

ammonium persulfate, after which required holes (including

those for sheet sizing and alignment) are punched in the

green sheet (copper will have been etched from the punching

sites).
5) Copper paste is next screened to f...