A high-sensitivity infrared detector requires small thermal capacitance and small thermal conductance to maximize the temperature change and signal induced by incident IR radiation. The suspended structure of infrared sensors provides ideal, thermally isolated, structures for support of the thin film detector. A new idea of improving CMOS thermopile performance is introduced to reduce the thermal conductance by dividing the thermocouple into several segments, which greatly increase the heat flow barrier. Then, adjacent segments are connected by a minimum width of alumina wire, which change the heat path and accumulated heat at the joint points. Several designs of infrared microsensors can improve performance of signal with reduce of thermal conductance. To that end, by using some adequate designs of polysilicon architecture, we can greatly reduce the heat flow from the main stream without introducing further electric resistance, which is related with noise. The design and simulation of thermopile sensors are realized by using the process parameters of standard 0.351m CMOS IC technology. Firstly we develop such a structure of thermopile with low thermal conductance and high performance by using CMOS compatible process which can be easily and naturally fabricated. The simulation results show good match with our original idea and great performance than before.

A high reliability and high thermal performance molding flip chip ball grid arrays structure which was improved from Terminator FCBGA®. (The structure are shown as Fig. 1) It has many advantages, like better coplanarity, high through put (multi pes for each shut of molding process), low stress, and high thermal performance. In conventional flip chip structure, underfill dispenses and cure processes are a bottleneck due to low through put (dispensing unit by unit). For the high performance demand, large package/die size with more integrated functions needs to meet reliability criteria. Low k dielectric material, lead free bump especially and the package coplanarity are also challenges for package development. Besides, thermal performance is also a key concern with high power device. From simulation and reliability data, this new structure can provide strong bump protection and reach high reliability performance and can be applied for low-K chip and all kind of bump composition such as tin-lead, high lead, and lead free. Comparing to original Terminator FCBGA®, this structure has better thermal performance because the thermal adhesive was added between die and heat spreader instead of epoxy molding compound (EMC). The thermal adhesive has much better thermal conductivity than EMC. Furthermore, this paper also describes the process and reliability validation result.

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