Dissertation > Industrial Technology > Radio electronics, telecommunications technology > Semiconductor technology > Semiconductor transistor ( transistor )

Finite Element Analysis of TSOP Failure during Mould Release and Temperature Distribution in Polysilicon TFT under Self-heating Stress

Author YangZhenYu
Tutor WangMingXiang
School Suzhou University
Course Microelectronics and Solid State Electronics
Keywords Finite Element Analysis Silicon fragmentation failure Plastic Stripping Stress Thin-film transistor Self-heating degradation Temperature distribution
Type Master's thesis
Year 2007
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In this paper, the finite element method to simulate a typical TSOP package products plastic stripping process . Using the finite element method simulation package TSOP package chips fragmentation may occur in the molding process , mold release , mold release to clarify the mechanism of the chip fragmentation failure . The study shows that a partially formed by the inner surface of the mold organics contamination may hinder smooth chip releasing, resulting in large local stress generated in the silicon wafer and fragmentation VALID . Confirmed through simulation in different stain size, shape and position of the package releasing the most likely causes of the failure condition . VALID chip fragmentation can be improved through the use of a high modulus of elasticity of the plastic material or to reduce the die size . This study has certain guiding significance for improving the reliability of the the TSOP chip package process . This article also simulate the low temperature polysilicon thin film transistor of the n-type MILC DC self-heating under stress device temperature distribution , respectively, the temperature distribution and power density loading characteristics of the substrate material , and the channel width of the device dependencies . The reduction in the power density of the device can directly reduce the unit area of ??the heat, thereby reducing the channel temperature . Under the same power density , the increase of the channel width will increase the heating area , thus reducing the channel width also has an important role in reducing the channel temperature . Improve the thermal conductivity of the substrate material , the better the channel of the heat emitted from the bottom of the device , or a small power density will produce a very high temperature . Transient temperature simulation devices , we can propose a characteristic time constant of the device . The time constant varies depending on the substrate material , using preferably a thermally conductive material can be reduced two orders of magnitude the constant . Studies have shown that lower power density , thermal conductivity of the substrate material , reducing the channel width to help to reduce the device self- heating effects . This study contributes to understanding of the degradation mechanisms and reveal self-heating , the reliability of the self-heating degradation of TFT device has a certain significance .

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