MANUFACTURE OF CIRCUIT ELECTRODE PORTION AND CIRCUIT ELECTRODE PORTION

PROBLEM TO BE SOLVED: To reduce spots and discolorations appearing on the surface of the gold film of a circuit electrode portion or the generations of the cracks of its pad portion and to form the circuit electrode portion with a good bonding ability by suppressing the erosions of its nickel film,...

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Bibliographische Detailangaben
Hauptverfasser:	TSUCHIYA JOJI, YAZAWA AKIRA, MINATO MAYUMI
Format:	Patent
Sprache:	eng
Schlagworte:	CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR ELECTRICITY MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS PRINTED CIRCUITS
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Beschreibung
Zusammenfassung:	PROBLEM TO BE SOLVED: To reduce spots and discolorations appearing on the surface of the gold film of a circuit electrode portion or the generations of the cracks of its pad portion and to form the circuit electrode portion with a good bonding ability by suppressing the erosions of its nickel film, when performing its electroless gold plating of a substitution type. SOLUTION: On the surface of a pad base portion 2, formed by a copper plating, a palladium film 3 is formed by an electroless plating to form thereon a nickel film 4 containing phosphorus by an electroless plating. On the surface of the nickel film 4, a gold film 5 is formed by a substitution type electroless plating. Since the phosphorus concentration of the nickel film 4 is lowers as it is nearer the palladium film 3 to its upper layer, the erosions of the nickel film 4 when forming the gold film 5 are suppressed.