环境技术

针对温度循环载荷下球栅阵列（BGA）封装结构在边角处焊点易发生疲劳损伤，导致焊点失效的问题，采用有限元分析法和Engelmaier修正的Coffin-Manson疲劳寿命模型，分析不同温度循环载荷下BGA焊点的应力应变及疲劳寿命。结果表明，芯片边角处焊点应力最大，在降温阶段等效应力达到最大值，边角处焊点比中心焊点更容易累积疲劳损伤而失效，是芯片中的危险焊点；-65～150℃温循条件比-55～125℃温循条件更严苛，危险焊点等效应力高18.30%、等效塑性应变高15.65%、寿命低39.54%。BGA封装边角焊点是温度循环下的失效敏感部位；更宽的温度循环范围会显著加剧BGA焊点的应力应变响应，导致其疲劳寿命急剧缩短。

To address the issue that the corner solder joints of ball grid array(BGA) package structures are prone to fatigue damage and subsequent failure under thermal cycling loads, the finite element analysis method and the Engelmaier-modified Coffin-Manson fatigue life model were employed to analyze the stress, strain, and fatigue life of BGA solder joints under different thermal cycling loads. The results show that the corner solder joints of the chip experience the maximum stress, with the equivalent stress reaching its peak during the cooling phase. Compared with the central solder joints, the corner solder joints are more susceptible to cumulative fatigue damage and failure, thus being the dangerous solder joints in the chip. The thermal cycling condition of-65 ～ 150 ℃ is more severe than that of-55 ～ 125 ℃ : under the former condition, the equivalent stress of the critical solder joints is 18.30% higher, the equivalent plastic strain is 15.65% higher, and the service life is 39.54% lower. In conclusion, the corner solder joints of BGA packages are failure-sensitive locations under thermal cycling; a wider thermal cycling range significantly intensifies the stress-strain response of BGA solder joints, leading to a sharp reduction in their fatigue life.