Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame – With separate tie bar element or plural tie bars
Reexamination Certificate
2006-12-12
2006-12-12
Owens, Douglas W. (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Lead frame
With separate tie bar element or plural tie bars
C257S669000, C257S676000, C257S730000, C257S780000
Reexamination Certificate
active
07148561
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.
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Ho Tzong Da
Huang Chien Ping
Yu Isaac
Corless Peter F.
Edwards Angell Palmer & & Dodge LLP
Gebremariam Samuel Admassu
Jensen Steven M.
Owens Douglas W.
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