Method for forming a temporary attachment between a semiconductor die and a substrate using a metal paste comprising spherical modules
US5468655A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 31, 1994 |
| Grant date | Nov 21, 1995 |
| Priority date | — |
| Expiry date | Oct 31, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49004
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A nodular metal paste (42) is used to temporarily attach the bumps (34) on a semiconductor die (32) to a substrate (38). The spherical nodules (44) composing the metal paste are dispensed onto contact pads (40) on the substrate, and then heated until they partially melt. The partial liquid region permits bonding of the individual metal nodules to the contact pads and to adjacent nodules. Subsequently, a bumped die is placed over the nodules and heated to a minimum temperature required to partially remelt to form a local tack joint. Because the metallurgical contact area between the paste nodules and the bumps is minimized, electrical contact can be sustained with a small cross-sectional area of connected material to create an electrically sound but physically weak link between die and the substrate. Once connected to the substrate, the die may be tested and burned-in, and removed afterwards with little damage to the bumps.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.