英语翻译3.1 Finite Element Modeling and Stress Analysis.In order

英语翻译
3.1 Finite Element Modeling and Stress Analysis.In order
to obtain the accurate damage model,thermal cycling test data
from different combinations of component types and thermal pro-
files are needed.Besides thermal cycling test data from this study,
another previous NCMS work,reported in the literature,is se-
lected and their test data are included into this study .Similar
fleXBGA144 packages with different die size from ours were em-
ployed in their tests and the corresponding FE models are devel-
oped with minimal modifications.More importantly,test data un-
der three different thermal profiles are available so that the effect
of the thermal profile can be addressed in the obtained durability
models.All five combinations of component type and thermal
profiles are summarized in Table 8 and in Fig.17.It is seen that
there are three component types,fleXBGA1,TABGA,fleXBGA2,
subjected to four different thermal cycle loading with temperature
range varying from 100°C to 180°C mean temperature from
35°C to 50°C?,ramp rate from 6°C/m in.to 90°C/m in.,and
also dwell time from 5 to 15 min.
The packages modeled include a 144-joint fleXBGA package
and a 96-joint TABGA package on FR4 board.There are two
models for fleXBGA144 packages with different die size.One has
Fig.15 Optical micrographs of PBGA352 solder joints 〓SAC ball/SnPb paste…
Fig.16 Overall approach for thermomechanical durability
analysis
Table 8 Summary of temperature profiles
Fig.17 Schematic of thermal profile
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the die size shown in Table 1 and the other one has a die size of
6.4 mm?6.4 mm?0.27 mm.Other dimensions are the same for
two fleXBGA144 packages.They are labeled as fleXBGA1 and
fleXBGA2,respectively.The FR4 PWB length is much larger
than the component and only a relevant part of the substrate is
modeled in the analysis.The distance between the centers of two
adjacent components is used as the length of the PWB in the FE
models.Dimension of solder joints is obtained by averaging mea-
surement of many solder joints after cross sectioning.
Nonlinear viscoplastic finite element analysis is conducted with
ANSYS 7.1.Three-dimensional quarter models are built up for fleX-
BGA144 and TABGA96 packages in the FE analysis due to the
symmetry in geometry.An example of FE model of fleXBGA144
package are shown in Fig.18.Solid element 185 is used in all FE
models.

有限元建模及应力分析.为了
获取准确的损伤模型,热循环试验数据
从组件类型和不同的组合热亲
文件是必要的.除了热循环从本研究的测试数据,
另一个以前新型农村合作医疗工作,在文献报告,是世
lected和他们的测试数据纳入本研究?9?.类似
fleXBGA144不同的芯片尺寸封装与我们的时间,
带台单桩在他们的测试和相应的有限元模型德弗尔-
以最小的修改制作的通讯资料.更重要的是,测试数据未
德三种不同的热分布,可这样的效果
的热剖面可以解决在取得耐久性
模型.组件式和热全部五种组合
配置文件列于表8和图. 17.可以看出,
有三个组件类型,fleXBGA1,TABGA,fleXBGA2,
受到四种不同热循环载荷与温度
范围从100℃至180℃不同?平均温度从
35 ° C至50 ° C的?从6℃/米英寸匝道率提高到90℃/米英寸,和
还停留时间由5至15分钟.
该套件为蓝本,包括一个144联合fleXBGA包
和96联合TABGA上的FR4电路板包.有两个
不同型号的fleXBGA144芯片尺寸封装.之一
图. 15光学PBGA352焊点形貌〓国资委球/锡铅膏...
图. 16总体方针的热机械耐久性
分析
表8摘要温度分布
图. 17热剖面示意图
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芯片尺寸见表1,另1人死于尺寸
6.4毫米?6.4毫米?0.27毫米.其他方面都是相同
二fleXBGA144包.他们被指为fleXBGA1和
fleXBGA2分别. FR4的工作计划和预算的长度大得多
超过部分,只对基板的有关部分
在分析模型.这两个中心之间的距离
邻近元件是用来作为工作计划和预算在铁的长度
模型.焊点尺寸均是获得多边环境协定,
许多焊点的几种常用交叉后切片.
非线性粘塑性有限元分析进行
ANSYS的7.1.三维模型,建立了季度的弹性
BGA144封装和TABGA96在有限元分析,由于
几何对称性.一种有限元fleXBGA144典范
包图所示. 18.固体元素185是用于所有有限元
模型.
（有些英文看不懂）