Method of fabricating a reworkable module
US5274913A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 25, 1991 |
| Grant date | Jan 4, 1994 |
| Priority date | — |
| Expiry date | Oct 25, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49146
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Disclosed is a reworkable circuit .package formed by controlled collapse chip connection ("C4") bonding of integrated circuit chips to circuit cards and boards, and direct chip attachment ("DCA") where an encapsulant is disposed under the chip. The encapsulant offers protection of the C4 connections and a thermal expansion matched to that of the C4 joints. However, most encapsulants interfere with reworkability. The disclosed circuit package overcomes this problem by the provision of a passivating layer of Parylene is reworkable, dry processable, uniformly depositable by vapor phase deposition, forming thin films on facing surfaces at the 3-5 micron film thickness corresponding to the C4 lift-off distance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.