Fluxing adhesive
US6467676B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 21, 2000 |
| Grant date | Oct 22, 2002 |
| Priority date | — |
| Expiry date | Sep 21, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K3/3489
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An improved underfill adhesive encapsulant with fluxing activities containing an epoxy resin or a mixture of epoxy resin. An anhydride is used as the curing agent to harden the epoxy resin. A hydroxyl-containing fluxing precursor compound is added to the encapsulant composition to react with the anhydride curing agent to produce an active fluxing agent under typical reflow conditions. The use of a fluxing precursor gives improved reliability compared to conventional fluxing agents used in existing no-flow underfill encapsulants. A suitable catalyst such as imidazole, imidazole derivative or metal acetylacetonate is provided in the present encapsulant at concentrations that give good curing kinetics. A thermoplastic is optionally included to allow the cured encapsulant to be reworked.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.