Compression layer on the leadframe to reduce stress defects
US5923081A · kind A · utility
10Cited by
34References
19Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | May 15, 1997 |
| Grant date | Jul 13, 1999 |
| Priority date | — |
| Expiry date | May 15, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/181
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An LOC die assembly includes a die dielectrically adhered to the underside of a lead frame. The active surface of the die underlying the attached lead frame is coated with a polymeric material such as polyimide. The underside of the lead frame overlying the die is coated with a layer of soft material, such as silver, which has a lower hardness than the coating on the active surface for absorbing point stresses. Penetration of stacked filler particles into the soft material reduces point stresses on the active die surface and disadhesion stresses on the lead frame components.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.