Ball grid array substrate strip with warpage-preventive linkage structure
US7148561B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 2001 |
| Grant date | Dec 12, 2006 |
| Priority date | — |
| Expiry date | Apr 23, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/3511
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A substrate strip with warpage-preventive linkage structure is proposed for a BGA (Ball Grid Array) application. The proposed substrate strip is composed of a series of substrates, each being used for the construction of an individual unit of a BGA package, and which is characterized by the provision of a warpage-preventive linkage structure, by which each substrate on the substrate strip is supported by means of no more than two tie bars, i.e., either by a two-point linkage structure or a one-point linkage structure, in contrast to the four-point linkage structure utilized by the prior art. During high-temperature fabrication steps when the substrate is subjected to thermal stresses, the substrate can freely expand toward the corners where no tie bars are provided; and consequently, it can be unwarped by the thermal stresses. This unwarped substrate allows the subsequently implanted ball grid array thereon to have high coplanarity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.