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为获得印制电路板组件(PCBA)的板厚、芯片布局等结构参数和随机振动谱型(功率谱密度,PSD)变化对球栅阵列(BGA)封装芯片焊点振动疲劳寿命的影响,利用HYPERMESH软件建立了带BGA封装芯片的PCBA三维有限元网格模型,并采用ANSYS软件对PCBA有限元模型进行了随机振动响应分析。结果表明,随着PCB厚度增加,BGA焊点振动疲劳寿命呈现明显提升的趋势,当PCB厚度由1.2 mm增加到2.2 mm时,BGA焊点振动疲劳寿命N由45363大幅增加到557386;合理的芯片安装间距能够明显增加焊点振动疲劳寿命,特别是当芯片安装在靠近固定约束并处于两个约束对称中间位置时;当PCBA的第一阶固有频率位于随机振动谱最大幅值对应的频率区间时,BGA焊点的振动疲劳寿命会明显降低。
In order to obtain the influence of structural parameters such as board thickness and chip layout of printed circuit board assembly (PCBA) and the variation of random vibration spectrum (power spectral density, PSD) on the vibration fatigue life of solder ball joints in ball grid array (BGA) HYPERMESH software builds PCBA three-dimensional finite element mesh model with BGA package chip and analyzes the random vibration response of PCBA finite element model with ANSYS software. The results show that as the PCB thickness increases, the vibration fatigue life of BGA solder joints increases obviously. When the PCB thickness increases from 1.2 mm to 2.2 mm, the vibration fatigue life N of BGA solder joints greatly increases from 45363 to 557386. The installation pitch can obviously increase the fatigue life of the solder joint vibration, especially when the chip is installed close to the fixed constraint and in the middle of two constrained symmetry. When the first natural frequency of PCBA is in the frequency range corresponding to the maximum amplitude of random vibration spectrum , BGA solder joint vibration fatigue life will be significantly reduced.