Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Patent
1995-09-27
1996-07-16
Thomas, Laura
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
174262, 174261, 174250, 174259, H05K 111
Patent
active
055369081
ABSTRACT:
A printed circuit is provided that is capable of operating at temperatures above 200.degree. C. A printed wiring board has a plating scheme of Tin plating over sulfamate nickel plated over copper. The materials are electroplated in the pattern of the desired circuit. The copper provides a conductive material for carrying electrical current. The sulfamate nickel is a ductile material that serves as a barrier between the copper and the Tin and is able to maintain its strength under temperatures of above 200.degree. C. The Tin is compatible with the new solder compound that is used to solder electrical components to the board. The solder compound is comprised of Tin and Silver. This solder has a higher initial melting point than traditional Tin/Lead solders but has a lower solder reflow temperature than conventional HMP solder compounds. This new solder is also stronger than conventional HMP solder and contains virtually no Lead component. A multilayer printed circuit is also provided that has a "Pads Only" design in which only the pads and short runs connecting to vias are allowed on the outer layers of the board. All power and signal runs are restricted to the inner layers of the board. This design has the advantage of protecting the runs in a high temperature environment and results in a more reliable assembly. The multilayer circuit uses the same plating scheme as in the above-described printed circuit.
REFERENCES:
patent: 4024631 (1977-05-01), Castillero
patent: 4104111 (1978-08-01), Mack
patent: 4572925 (1986-02-01), Scarlett
patent: 4597828 (1986-07-01), Tadros
patent: 4605471 (1986-08-01), Mitchell
patent: 4632484 (1986-12-01), Sinclair
patent: 4633050 (1986-12-01), Samuels
patent: 4732649 (1988-03-01), Larson et al.
patent: 4904968 (1990-02-01), Theus
patent: 4963701 (1990-10-01), Yasumoto et al.
patent: 4985600 (1991-01-01), Heerman
patent: 5235139 (1993-08-01), Bengston et al.
Etchells Richard K.
Tawyea Lawrence E.
Schlumberger Technology Corporation
Thomas Laura
Walker Darcell
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