模拟器件稳态热场正确性的判断方法

对稳态热场，二个水平剖面A和B所夹的薄层上的温差必须严格等于本文提出的平均值定理的计算值．当芯片、基片和底座的截面大小一样时，可以直接根据平均值定理计算出芯片、基片和底座的每一水平剖面上的平均温度，通常可以手工完成；当芯片、基片和底座的截面大小不一样时，可以通过数据合成根据平均值定理计算出芯片、基片和底座的每一水平剖面上的平均温度．如果计算中有的参数如沟道长度不十分清楚时，应作模拟了解该参数对热斑温度的影响，必要时对该参数进一步了解以保证模拟精度．

A Method of Verifying Simulated Steady Thermal Field of a Semiconductor Device

The 3-D thermal simulation of a realistic semiconductor device is diverse and error prone，so it is desired to be verified at the design stage．Besides the trivial morphology check，in which the shape of simulated thermal field must consist with the heat source of the device，a new method，average value check is proposed in this paper to judge the simulation results．If the simulation is correct，the average temperature of any horizontal cross section is equal to the predicted values of the chip，substrate and heat sink．And the average temperature can be predicted as follows：on condition that the average temperature drop over the layers，paralleling the bottoms of heat sink，equals the one predicted by the average theorem proposed；if the cross sections of the chip，substrate and heat sink are same sized，it can be obtained by directly from the average theorem；otherwise，it can be obtained using the average theorem together with the data synthesizing．To obtain a reliable result，it is necessary to simulate the dependence of the hottest spot temperature on an inaccurate parameter，if have，and then to determine the error of this temperature caused by the uncertainty of the parameter．This method is proved by simulating of GaAs MESFET and a Si BJT microwave device，with the results in good agreement with the experimental ones．