Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Physical dimension specified
Patent
1981-05-08
1983-03-22
Smith, John D.
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Physical dimension specified
29577R, 29577C, 29590, 156278, 156289, 174 685, 357 70, 357 80, 427 96, 427259, 427 82, 427421, 4274301, 428336, 428339, 428901, H05K 100, H01L 2158
Patent
active
043776191
ABSTRACT:
Method for preventing spreading of a liquid on a solid surface, e.g., an adhesive placed on a substrate, and for preventing metal migration, in particular silver migration, between conductors deposited on a surface of a substrate, and articles produced by the method. The method comprises application of a layer of polymer having room temperature critical surface tension of wetting less than about 20 dyn/cm, and less than about 0.1 .mu.m thick, to at least a part of the surface. The polymer layer can be applied by any convenient method, including dipping, spraying, painting, printing, and plasma deposition. A preferred polymer is poly(1H, 1H-pentadecafluorooctyl methacrylate) (PDFOM), which can be advantageously applied in the form of a solution, typically in a fluorinated hydrocarbon such as Freon.RTM. TF, with PDFOM concentration typically between about 0.001% and about 2% by weight. Thin PDFOM layers according to the invention covering the substrate area on which the adhesive is placed later do not unduly decrease the strength of the adhesive bond formed, and have no measurable effect on the electrical conductivity of a conducting adhesive bond. Because of these properties, a substrate surface can be coated with PDFOM, such as by dipping or spraying, and the adhesive be applied to the coated surface. Metal migration is prevented by preventing formation of a continuous electrolyte film, typically an aqueous film, between conductors at different electrical potentials. This can be achieved by coating at least a part of the substrate with the polymer, e.g., PDFOM.
REFERENCES:
patent: 3909680 (1975-09-01), Tsunashima
patent: 4100037 (1978-07-01), Baron
patent: 4143456 (1979-03-01), Inoue
Zisman, "Relation of the Equilibrium Contact Angle to Liquid and Solid Constitution," Advances in Chemistry Series, 43, pp. 1-50, American Chemical Society, Washington, D.C., (1964).
Shafrin, "Critical Surface Tensions of Polymers, " Polymer Handbook, 2nd Edit., pp. III-221-III-228, Wiley Interscience, (1975).
Kohman et al., The Bell System Technical Journal, vol. 34 (6), pp. 1115-1147, (1955).
Chaikin et al., Industrial and Engineering Chemistry, vol. 51 (3), pp. 299-304, (1959).
Schonhorn Harold
Sharpe Louis H.
Bell Telephone Laboratories Incorporated
Pacher Eugen E.
Smith John D.
Wilde Peter V. D.
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