A novel MEMS package with three-dimensional stacked modules

A 3D stacked modular packaging technology was developed so as to meet the general requirements of MEMS and wireless communication on packaging. The general requirements include high-density, low-cost and high-yield etc. According to the requirements of modular package, a kind of accelerator (MEMS) and its modem circuits (IC) were incorporated by three stacked modules and a 3D stacked modular package was realized. In this package, every module was assembled by using traditional surfaced mounting technology (SMT) based on FR4 substrate. MEMS and IC devices were assembled in the same module. The vertical interconnection between modules was realized by means of solder paste printer, mechanical alignment apparatus and optimized reflow curve. The mechanical alignment apparatus was specially prepared for alignment and positioning of stacked modular assembly. The alignment of stacked modules was completed by the alignment-pin/hole method. In order to increase the alignment efficiency, the module substrate was design as paste-up, for example 3times3. The alignment precision of vertical interconnection of the stacked modules reaches to 0.068 mm typically. The volume of the entire stacked module was about 19 mmtimes19 mmtimes8 mm. Finally, the influencing factors on the vertical interconnection were discussed and shear strength test of the module was presented.