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Title: Improved methods of fabricating multilayer printed wiring boards. Final report

Abstract

A reliable process for the fabrication of multilayer printed wiring boards has been further improved by implementing a solder-dip-and-level process in place of the conventional pattern-tin-lead-plate process. A commercial chronic acid etchant has proven to be superior to the previously used sulfuric acid etchback solution. An economical, disposable polyvinyl-fluoride-film release sheet has been adopted, and a nuclear static-electricity eliminator has proven effective in providing lint-free panels.

Authors:
Publication Date:
Research Org.:
Bendix Corp., Kansas City, Mo. (USA)
OSTI Identifier:
5264887
Report Number(s):
BDX-613-1657
DOE Contract Number:
EY-76-C-04-0613
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; PRINTED CIRCUITS; FABRICATION; ELECTROSTATIC CHARGE ELIMINATORS; RADIOISOTOPES; ELECTRONIC CIRCUITS; ISOTOPES; 420800* - Engineering- Electronic Circuits & Devices- (-1989)

Citation Formats

Wilson, J.L. Improved methods of fabricating multilayer printed wiring boards. Final report. United States: N. p., 1978. Web. doi:10.2172/5264887.
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Wilson, J.L. Improved methods of fabricating multilayer printed wiring boards. Final report. United States. doi:10.2172/5264887.
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Wilson, J.L. Sun . "Improved methods of fabricating multilayer printed wiring boards. Final report". United States. doi:10.2172/5264887. https://www.osti.gov/servlets/purl/5264887.
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@article{osti_5264887,
title = {Improved methods of fabricating multilayer printed wiring boards. Final report},
author = {Wilson, J.L.},
abstractNote = {A reliable process for the fabrication of multilayer printed wiring boards has been further improved by implementing a solder-dip-and-level process in place of the conventional pattern-tin-lead-plate process. A commercial chronic acid etchant has proven to be superior to the previously used sulfuric acid etchback solution. An economical, disposable polyvinyl-fluoride-film release sheet has been adopted, and a nuclear static-electricity eliminator has proven effective in providing lint-free panels.},
doi = {10.2172/5264887},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 1978},
month = {Sun Jan 01 00:00:00 EST 1978}
}
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Technical Report:
View Technical Report (5.16 MB)
DOI:  10.2172/5264887
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  • Copper foil adhesion to polyimide/glass prepreg was evaluated. Typical peel strength obtained between prepreg and the smooth side of the copper foil was 1 to 3 lb./in. width. Peel strength between prepreg and the rough side of the copper foil ranged between 6 and 7 lb./in. width. An alternate test for evaluating the integrity of multilayer printed wiring boards is described.

  • Multilayer printed wiring boards (PWBs) were manufactured from a polyimide/glass reinforced copper-clad laminate and prepreg. A lamination cycle and innerlayer copper surface treatment were developed that gave satisfactory delamination resistance at soldering temperatures. When compared to similar epoxy/glass multilayer PWBs, the polyimide PWBs had higher thermal stability, greater resistance to raised lands, fewer plating voids, less outgassing, and adhesion that was equivalent to urethane foam encapsulants.

  • Three multifunctional epoxy/glass printed wiring board (PWB) laminates, along with standard FR4 laminate from production stores, were evaluated for their susceptibility to raised lands around the plated through-holes of PWBs. However, after thermal stress tests, the angles of the lands were measured in relation to the PWB surface, and the results were surprisingly similar. None of the materials that were tested stood out as being far better than the others in regard to reduced raised land susceptibility. Judging from the Z-axis thermal expansion curves, the similar average and angles measured after thermal stress tests, and rework simulation tests, it wasmore » not evident that any of these multifunctional epoxy systems would resolve the recurring problem of raised lands on channel-plated PWB product at Allied-Signal Inc., Kansas City Division. 2 refs.« less

  • A solvent containing the chlorinated hydrocarbon 1,1,1-trichloroethane, was previously used to clean printed wiring boards following the contouring and inspection operations. An alkaline detergent was selected and evaluated as a replacement. Tests showed the detergent produced an acceptable level of cleanliness (resistance readings greater than 2 megohm-centimeters).

  • A solvent containing the chlorinated hydrocarbon 1,1,1-trichloroethane, was previously used to clean printed wiring boards following the contouring and inspection operations. An alkaline detergent was selected and evaluated as a replacement. Tests showed the detergent produced an acceptable level of cleanliness (resistance readings greater than 2 megohm-centimeters).