Method of molding a thermoplastic ring onto a leadframe
US5213748A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 27, 1991 |
| Grant date | May 25, 1993 |
| Priority date | — |
| Expiry date | Jun 27, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/181
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
In a pre-molded package assembly, a thermoplastic ring molded onto a leadframe must maintain lead coplanarity. In this invention a plastic member of liquid crystal polmar is molded onto the leads of a metal leadframe. The plastic member is a thermoplastic anisotropic material which, when formed, has a flow direction which is in the long dimension of the plastic member and a transverse direction which is in the short dimension of the plastic member. Dam members on the leadframe help contain the plastic molding compound within the mold cavity during the molding process. A puddle gate prevents the formation of a weld line in the plastic member. Upon completion of the molding process, the dam members are excised from the leadframe to provide discrete leads.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.