Modified Reynolds Equation for Squeeze-Film Air Damping of Slotted Plates in MEMS Devices

A differential equation for calculating squeeze-film air damping in slotted plates is developed by modifying the Reynolds equation. A term is added to account for the effect of airflow through the slots on the air damping of the plate. The end effect of the airflow in the slots is also treated by substituting an effective channel length for the geometric channel length （i. e. the thickness of the plate）..The damping pressure distribution, damping force, and damping force coefficient of the slotted plates can be found by solving the equation under appropriate boundary conditions. With restrictions on the thickness and the lateral dimensions of the slotted plate removed,the equation provides a useful tool for analysing the squeeze-film air damping effect of slotted plates with finite thickness and finite lateral dimensions. For a typical slotted plate structure, the damping force coefficient obtained by this equation agrees well with that generated by ANSYS.

VDMOS器件贴片工艺中气泡的形成机制与影响

功率MOS管的封装贴片工艺会在贴片层中引入气泡,从而严重降低器件的机械性能、热性能和电学性能。本研究就VDMOS管D-PAK封装模式,给出了贴片工艺中气泡的产生机制及其影响,并利用FEA方法建立了其D-PAK封装的热学模型。根据模拟结果,在贴片层中气泡含量提高时,热阻会急剧增大而降低器件的散热性能。

适用于可编程IP核的布图方法

提出了一套适用于可编程IP核的布图系统PRPIC(PlacementandRoutingSystemforProgrammableIPCore)。该系统对可编程IP核的结构进行抽象建模,并根据该模型生成用于布图的实际电路的有向资源图,从而可以灵活地支持规模和结构不同的可编程IP核。根据可编程IP核结构和应用等方面的特殊性,对布图算法进行了优化。