Ball grid array substrate strip with warpage-preventive linkage structure

Abstract

A substrate strip with warpage-preventive linkage structure is proposed for 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 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 expanded 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.

Dependencies are inferred from the claim text.