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Multilayer Circuit Fabrication

IP.com Disclosure Number: IPCOM000093360D
Original Publication Date: 1967-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Peter, AE: AUTHOR [+3]

Abstract

Multiple layer printed circuits can be constructed with greater density by adding the conductive and dielectric layers singly.

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Multilayer Circuit Fabrication

Multiple layer printed circuits can be constructed with greater density by adding the conductive and dielectric layers singly.

In A, a layer of conductive material 1, such as copper, is deposited on substrate 2 to a thickness equivalent to the combined thickness of the required dielectric and circuit planes. Conductor 1 is etched to form a pattern of interconnecting studs 3. Then thermosetting dielectric 4 is coated on conductor 1 to fill in the etched area and sanded, when cured, to uncover the tops of studs 3.

In B, a second layer 5 of conductive material is deposited on the studs and dielectric by electroless deposition, vacuum metallization or the like, followed by electrolytic deposition to achieve circuit thickness. Layer 5 is etched to provide the desired circuits. Thermosetting dielectric 6 is coated on the etched areas, cured, and then sanded to expose circuit layer 5.

In C, a third layer 7 of conductive material is deposited on circuit layer 5 and dielectric 6 to a thickness equivalent to the required dielectric and etched to leave a pattern of studs. Dielectric layer 8 is coated, cured, then sanded to expose the studs.

Additional layers are added as shown in D by repeating the sequence of steps shown at B and C as required. Then the fabricated multiple layers are removed from substrate 2. The substrate side of original conductive layer 1 is etched to the desired circuit pattern.

The etched areas are again filled with diel...