LEAD FRAME

PURPOSE:To improve on solder wettability in a packaging process for the prevention of burr-caused difficulties during transportation by a method wherein a lead frame is subjected to punching accomplished from its top surface and rear surface, only the burrs on leads are allowed to protrude from the...

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Bibliographic Details
Main Author ENOMOTO USUKE
Format Patent
LanguageEnglish
Published 20.09.1988
Subjects
BASIC ELECTRIC ELEMENTS
CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS
ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
ELECTRICITY
MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
PRINTED CIRCUITS
SEMICONDUCTOR DEVICES
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Summary:PURPOSE:To improve on solder wettability in a packaging process for the prevention of burr-caused difficulties during transportation by a method wherein a lead frame is subjected to punching accomplished from its top surface and rear surface, only the burrs on leads are allowed to protrude from the rear surface, and the other burrs are allowed to protrude from the top surface. CONSTITUTION:A lead frame 16 is built of a thin metal plate subjected to punching by a precision press. Punching is accomplished from the top surface and rear surface of the lead frame 16. Burrs 4 on both sides of leads 1 are present on the rear surface of the lead frame 16. Burrs 4 on the lead frame circumference are present on the top surface of the lead frame 16 where a chip 14 is installed. This design well prevents burrs 4 from arresting a work bench to interrupt the transportation of the lead frame 16. The three leads 1 protruding from a package 11 of microstructure transistors 10 are coated with solder 3 in a dipping process, when a relatively easy adhesion is ensured for the solder 3 in the presence of the burrs 4 on both edges of the upper surface of fixing sections 12 for the leads 1.
Bibliography:Application Number: JP19870058812