【摘要】 水分对印制电路板的可靠性有重要影响。电路板中的水分子可以改变电路基板的热性能及热力学性能,从而影响电路板及元器件的正常功能。研究了吸湿对两种无卤PCB及两种含卤PCB层压板热膨胀系数的影响,评价了IPC-TM-650 2.4.24测试方法中预处理方法对吸湿样品的适用性。结果表明,PCB层压板中的水分对PCB层压板的热膨胀曲线有明显影响,但传统的热膨胀系数计算方法并不能显示这种影响,对此作了详细分析并提出了改进建议。同时,IPC测试方法中的预处理可以降低湿度对样品热膨胀曲线的影响,但不能完全消除。更多还原

【Abstract】 Moisture plays an important role in the integrity and reliability of printed circuit boards(PCB).The presence of moisture in a printed circuit boards alters its thermal performance and thermo-mechanical properties,thereby affecting overall performance.It is studied that the effect of moisture on coefficient of thermal expansion(CTE) of PCB laminates.Four types of PCB materials from two manufacturers,including two halogen-free and two halogenated,are tested.It is established whether preconditioning steps outlined in the IPC-TM-650 2.4.24 test method account for varying moisture contents in laminate samples.The results show that moisture obviously affects the thermal expansion curves of PCB laminate,however,the common calculation for CTE can not show the difference.Detailed analysis and improving suggestion are presented in this paper.Although the effect of moisture on thermal expansion curves can be decreased by preconditioning the samples as the IPC test method,it can not be eliminated entirely.更多还原