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Low Expansion Flush Circuit Substrate Process

IP.com Disclosure Number: IPCOM000039902D
Original Publication Date: 1987-Aug-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Ballard, GL: AUTHOR [+3]

Abstract

The production of thin laminate circuit boards is typically accomplished by additive or subtractive means and involves the extensive use of handling equipment. A particular processing problem is the necessity of keeping the laminate flat to prevent the cracking of the dielectric material. A method of producing thin flush circuit boards using a flat plated carrier to protect the dielectric material is described in this article. A rigid carrier (Fig. 1a), metal or plastic, is used as the lamination plate carrying the plated circuit. The carrier is mechanically cleaned to roughen the carrier surface. The carrier is then acid copper plated (Fig. 1b) over the entire surface with a thin layer of copper which is used as a base for the circuit.

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Low Expansion Flush Circuit Substrate Process

The production of thin laminate circuit boards is typically accomplished by additive or subtractive means and involves the extensive use of handling equipment. A particular processing problem is the necessity of keeping the laminate flat to prevent the cracking of the dielectric material. A method of producing thin flush circuit boards using a flat plated carrier to protect the dielectric material is described in this article. A rigid carrier (Fig. 1a), metal or plastic, is used as the lamination plate carrying the plated circuit. The carrier is mechanically cleaned to roughen the carrier surface. The carrier is then acid copper plated (Fig. 1b) over the entire surface with a thin layer of copper which is used as a base for the circuit. The thin layer of copper on the circuit is treated to accept photoresist, and the photoresist is applied. A circuit pattern is exposed on the photoresist and developed (Fig. 1c). The carrier is then plated with copper on the circuit pattern (Fig. 1d). The photoresist is then stripped, leaving the circuit pattern on a rigid carrier ready for lamination. The carrier is now used as the pin front-to-back plate for lamination (Fig. 1e). After the lamination the edge copper is cut and a laminate is stripped from the carrier plate (Fig. 1f). The laminate is then flash etched and a flush circuit (Fig. 1g) is produced. The surface exposed on the flush circuit is the plated copper. The surface i...