摘要集成电路的飞速发展使得从封装到电子设备的单位体积功耗和发热量不断增加，电子系统散热问题需要在设计阶段通过热仿真给予充分考虑和预测，电子封装作为系统的最小组成部分，其简化模型的优劣直接影响电子系统的速度和准确性。本文基于热力学理论，针对典型软封装体 COB 在工作过程中受热分析问题，考虑到 COB 封装的不规则性，在内外部环境相似的前提下，采用典型塑料方形扁平封装体PQFP模型模拟COB，建立有限元数值模拟分析模型。研究了封装体在工作情况下由于热载荷作用而产生的热应力分布情况。数值结果表明，采用较小弹性模量和热膨胀率的材料可以有效地减小热应力，基板和芯片的厚度是影响封装体变形的主要参数，数值分析结果为提高封装件的可靠性和优化设计提供了理论依据。7996
关键字 有限元 电子封装 热应力 热力学 Title Thermal stress analysis of the on-board chip
Abstract
The rapid development of integrated circuits made from the packaging
to the electronics unit volume increased power consumption and heat .Heat
dissipation of electronic systems in the design stage need to be given full
consideration by thermal simulation and prediction .Electronic packaging
components as a system of minimum.Simplified model of its direct impact
on the merits of speed and accuracy of electronic systems.Based on the
thermodynamic theory. The precondition that internal and external
environment is similar and taking into account of the irregularity of the
COB packaging,for analysis of the problem for the typical soft package COB
heat in the course of their work,we use typical of plastic quad flat pack
PQFP to model COB. ANSYS numerical simulation model established.Studied
the case of the package in the work load generated due to thermal stress
distribution.Numerical results show that,A smaller elastic modulus and
thermal expansion of the material can effectively reduce the thermal
stress.Thickness of the substrate and chip deformation of the main
parameters of the package .Numerical results to improve the reliability
of components and optimization package designed to provide a theoretical
basis.
Keywords ANSYS Electronic packaging Thermal stress Thermodynamics
目 次
1绪论 1
1.1电子封装技术介绍 1
1.2电子封装的种类 · 2
1.3COB电子封装与PQFP电子封装 3
1.4小结 · 4
2 PQFP电子封装受热理论分析 . 6
2.1热弹性力学的理论基础 6
2.1.1 热力学第一定律 . 6
2.1.2 熵，热力学第二定律 . 9
2.2热传导问题的有限元法 · 11
2.3热弹性问题的有限元法 · 13
2.4ANSYS热应力分析简介 16
3应用有限元模拟温度场和应力场 19
3.1模型参数 19
3.2建立有限元模型 20
3.2.1定义单元类型 20
3.2.2定义材料性能参数 20
3.2.3建立有限元模型 23
3.3网格划分及载荷施加 23
3.3.1网格划分 . 23
3.3.2施加温度载荷 24
3.4求解及后处理 · 24
3.5进入结构分析 · 25
3.5.1单元类型转换 25
3.5.2定义约束和等效荷载 25
3.5.3应力求解及后处理 25
4不同封装参数下对热应力的影响 26
4.1粘结剂材料的影响 · 26 板上芯片的热应力分析+文献综述:http://www.youerw.com/wuli/lunwen_6164.html