THREE-DIMENSIONAL PACKAGING AND ASSEMBLY OF HIGH-CAPACITY MEMORY MODULES

摘要

Dual-inline Memory Modules (DIMM) used in Personal Computer (PC) applications are continuously increasing in memory capacity to meet the never-ending demand in computational power. One conventional way to double the memory capacity without drastically affecting the DIMM module size and form factor is using pre-stacked, three-dimensional (3-D) packages. Two-high stacked Thin Small Outline Packages (TSOP) is one prominent example used commonly in DIMM modules. Stacked CSPs and other forms of overhanging, 3-D package assemblies are fast becoming more prevalent for workstation and server applications. This paper reviews the commonly used stacked package assemblies for DIMM modules and describes a new approach combining two dissimilar packages, a modified TSOP and a standard chip scale package (CSP) in a 3-D, overhanging package assembly. The fabrication of the modified TSOP, called high thin small outline package (HTSOP) is described first. The assembly procedures for the 3-D stacking DIMM assembly, called Elevated Package' Over CSP (EPOC) technology, is then discussed. Also included are the reliability results and thermal analysis and characteristics of this newly configured, high- capacity DIMM module assembly.