MCM温度场稳态分析报告Word文档下载推荐.docx
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芯片
硅
7×
0.65；
5×
0.65
82
芯片凸点
5Sn/95Pb
7，6×
6，Ф0.3，Height:
0.2,Pitch:
0.75
36
基板
Al2O3+BeO
25×
1.5
20
焊料球
96.5Sn3.5Ag
10×
10,Ф0.6,Height:
0.4,Pitch:
1.27
33
PCB
FR4
50×
8.37,8.37,0.32
热介质材料
导热脂
Thick:
0.15
1
粘接剂
1.1
热扩展面
铜
390
分析
从而导致器件性能变化和可靠性的下降。
热场分析和设计是MCM设计中一个重要的环节[3]。
MCM器件中的热应力来自两个方面，即来自MCM模块部和MCM模块所处的外部环境所形成的热应力，这些热应力都会影响到器件的电性能、工作频率、机械强度和可靠性。
随着MCM集成度的提高和体积的缩小,尤其是对于集成了大功率芯片的MCM,其部具有多个热源，热源之间的热耦合作用较强，单位体积的功耗很大，由此带来的芯片热失效和热退化现象突出。
有资料表明,器件的工作温度每升高10oC，其失效率增加1倍[4]。
因此,准确模拟大功率MCM模块的三维温度场分布，并分析掌握其热特性，有利于指导MCM热设计方案的选择，对提高大功率MCM的可靠性具有重要意义。
本文针对某球栅阵列封装的大功率MCM，提出了一种简化的热学模型，并利用有限元方法,借助有限元通用程序ANSYS,对其进行三维温度场的稳态模拟和分析。
方案步骤如下：
1、建模：
图4-1MCM几何模型图
图4-2MCM网格划分图
2、施加载荷计算
a、初始温度及对流系数（施加于模型外表面，即与空气接触的部位）
图4-3施加载荷后分析图
b、分析处理（温度云图）结果如下：
图4-4温度云图
3、后处理：
图4-5热沉的芯片部温度分布云图
图4-6芯片凸点（5Sn/98Pb）温度分布
图4-7基板（聚酰亚胺）温度分布云图
图4-8焊料球（37Sn/63Pb）温度分布云图
图4-9PCB（FR4）温度分布云图
图4-10热扩展面（铜）温度分布云图
4简要分析
从以上的分析结果可以得出：
最高温度出现在中间大芯片区域，MCM部有源功率芯片是热源的主要贡献者，芯片产生的热量主要沿芯片背面方向传递；
加散热装置来对大功率MCM进行降温是一种直接有效的方式；
另外，在相同条件下，合理的结构布局，如避免大功率器件过分集中不仅能降低结点温度最大值，而且能避免热集中现象，提高MCM组件的可靠性。
针对球栅阵列封装的大功率MCM其部具有多个热源、耦合作用强、部发热量大、温度高的特点，建立其热学模型，在ANSYS平台下对其进行了稳态模拟分析；
结果表明，增加外部散热装置可以大大降低MCM的温度，是对其进行降温最直接有效的一种方式；
合理布局可以避免热集中现象。
5结论
在MCM器件部，热场对器件的性能和可靠性有严重的影响，热场分析是MCM设计中的重要环节。
利用ANSYS软件对一球栅阵列的MCM进行了模拟分析，结果表明：
1）多芯片组件中,大功率芯片为模块中热源的主要贡献者,芯片最高温度点位于中间大芯片区域。
2）MCM几种降低温度的方法：
加外部散热装置是一种直接有效的对MCM进行降温方式（有散热装置的最高温度是134.oC，没有散热的布局温度大概达350oC）；
在相同条件下，合理的结构布局，能降低结点温度最大值，提高MCM组件的可靠性。
命令流
/BATCH
WPSTYLE,,,,,,,,0
/FILNAME,homework4,0
/TITLE,3D_analysisofMCMheatdissipation
/PREP7
ET,1,SOLID70
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,KXX,1,,82
MPDATA,KXX,2,,36
MPDATA,KXX,3,,20
MPDATA,KXX,4,,33
MPDATA,KXX,5,,8.37
MPDATA,KYY,5,,8.37
MPDATA,KZZ,5,,0.32
MPDATA,KXX,6,,1
MPDATA,KXX,7,,1.1
MPDE,KXX,6
MPDATA,KXX,8,,390
BLOCK,0,0.05,0,0.05,0,0.0015,
BLOCK,0,0.02,0,0.02,0.0019,0.0034,
BLOCK,0,0.02,0,0.02,0.00355,0.00505,
BLOCK,0,0.017,0,0.017,0.00355,0.0044,
VSBV,3,4
BLOCK,0,0.004,0,0.004,0.0036,0.00425,
BLOCK,0,0.0025,0.0085,0.0135,0.0036,0.00425,
BLOCK,0.0085,0.0135,0,0.0025,0.0036,0.00425,
wpoff,0,0,0.0017
SPH4,0.000635,0.000635,0.0003
BLOCK,0,0.001,0,0.001,0.0002,0.0006,
BLOCK,0,0.001,0,0.001,-0.0002,-0.0006,
FLST,3,2,6,ORDE,2
FITEM,3,8
FITEM,3,-9
VSBV,7,P51X
NUMCMP,VOLU
FLST,3,1,6,ORDE,1
FITEM,3,7
VGEN,13,P51X,,,0.00127,,,,0
FLST,3,13,6,ORDE,2
FITEM,3,-19
VGEN,13,P51X,,,,0.00127,,,0
wpoff,0,0,0.0018
SPH4,0.000275,0.000275,0.00015
BLOCK,0,0.001,0,0.001,0.0001,0.0006,
BLOCK,0,0.001,0,0.001,-0.0001,-0.0006,
FITEM,3,177
FITEM,3,178
VSBV,176,P51X
FITEM,3,179
VGEN,5,P51X,,,0.00075,,,,0
FLST,3,5,6,ORDE,2
FITEM,3,176
FITEM,3,-180
VGEN,5,P51X,,,,0.00075,,,0
VGEN,2,P51X,,,0.00875,,,,0
FITEM,3,201
VGEN,6,P51X,,,0.00075,,,,0
FLST,3,6,6,ORDE,2
FITEM,3,-206
VGEN,3,P51X,,,,0.00075,,,0
VGEN,2,P51X,,,,0.00875,,,0
FITEM,3,219
VGEN,6,P51X,,,,0.00075,,,0
FITEM,3,-224
VGEN,3,P51X,,,0.00075,,,,0
BLOCK,0.017,0.02,0,0.017,-0.0001,0.00005,
BLOCK,0,0.02,0.017,0.02,-0.0001,0.00005,
wpoff,0,0,0.00075
BLOCK,0,0.004,0,0.004,0,0.00015,
BLOCK,0.0085,0.0135,0,0.0025,0,0.00015,
BLOCK,0,0.0025,0.0085,0.0135,0,0.00015,
WPAVE,0,0,0
CSYS,0
wpoff,0,0,0.00505
BLOCK,0,0.02325,0,0.02325,0,0.0015,
BLOCK,0.02175,0.02325,0,0.02325,0.0015,0.0085,
FITEM,3,243
VGEN,8,P51X,,,-0.003,,,,0
VSEL,S,LOC,Z,0.00505,0.02
FINISH
/SOL
FLST,2,9,6,ORDE,2
FITEM,2,242
FITEM,2,-250
VADD,P51X
VSEL,S,LOC,Z,0.0034,0.00425
VSEL,U,,,5
FLST,2,2,6,ORDE,2
FITEM,2,
FITEM,2,216
VDELE,P51X,,,1
ALLSEL,ALL
FLST,2,240,6,ORDE,7
FITEM,2,1
FITEM,2,-
FITEM,2,-215
FITEM,2,217
FITEM,2,-241
FITEM,2,251
VGLUE,P51X
VDELE,249,,,1
VSEL,S,LOC,Z,0,0.0015
CM,_Y,VOLU
VSEL,,,,250
CM,_Y1,VOLU
CMSEL,S,_Y
CMSEL,S,_Y1
VATT,5,,1,0
CMDELE,_Y
CMDELE,_Y1
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