Surface metal balancing to reduce chip carrier flexing
US6497943B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 14, 2000 |
| Grant date | Dec 24, 2002 |
| Priority date | — |
| Expiry date | Feb 14, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24917
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A surface metal balancing structure for a chip carrier, and an associated method of fabrication, to reduce or eliminate thermally induced chip carrier flexing. A substrate, such as a chip carrier made of organic dielectric material, is formed and includes: internal circuitization layers, a plated through hole, and outer layers comprised of an allylated polyphenylene ether. A stiffener ring for mechanically stabilizing the substrate is bonded to an outer portion, such as an outer perimeter portion, of the top surface of the substrate, in light of the soft and conformal organic material of the substrate. The top and bottom surfaces of the substrate have metal structures, such as copper pads and copper circuitization, wherein a surface area (A) multiplied by a coefficient of thermal expansion (C) is greater for the metal structure at the bottom surface than for the metal structure at the top surface. A metal pattern is adjacent to the top surface so as to make the product AC of metal structures at or near the top and bottom surfaces approximately equal. The metal pattern reduces or eliminates flexing of the substrate in an elevated temperature environment, such as during a reflow of s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.