高性能覆铜板可靠性的快速表征方法和失效机理研究

RELIABILITY OF HIGH-PERFORMANCE COPPER CLAD LAMINATE — STUDIES ON FAILURE MECHANISMS USING A QUICK CAF TEST METHOD

王忠伟

11930221

硕士

材料工程

王珂

2021-05-23

2021-06-15

南方科技大学

深圳

近年来，随着电子设备的小型化和高度集成化，越来越多的组件被安装在印刷电路板（Printed Circuit Board，PCB）表面，加上更高的处理温度和工作电压，由导电阳极丝（Conductive Anodic Filament，CAF）引发的失效风险也逐渐增加，极大的限制了PCB应用场景和使用寿命。CAF发生的敏感性与PCB的整个制作流程及基板材料（即覆铜板，Copper Clad Laminate，CCL）本身属性存在很大关联，而改进PCB耐CAF性能的主要途径之一是对基板材料进行优化以降低其对CAF敏感性，包括原材料的筛选、玻纤/树脂基体界面的设计、加工工艺的控制等等。这涉及到大量的实验数据，而现有的CAF标准测试方法所需的测试周期长、成本高、信息量小，难以满足要求。本工作提出了一种快速测试CAF敏感性的方法，为行业提供用于材料研发、产品质保、原材料筛选、PCB设计优化的快速、有效、低成本的检测工具。同时该方法使得大量CAF数据的积累成为可能，可为将来基板材料的智能制造提供重要参考。本工作重新设计了CAF测试板并在湿度、温度、偏压等条件下测试，对比现有标准测试板的响应规律，对新设计的合理性进行了讨论，并对现有的CAF测试程序进行了优化。以光学显微镜，扫描电镜/能谱等方法对失效的测试板进行了切片分析，对失效机理进行了研究，确认了优化后的快速CAF测试程序的有效性。研究发现CAF中可能包含单质铜和铜盐，二者表现出的电阻随湿度变化的规律不同。前者为主时，短路一旦发生即不可恢复绝缘，而后者为主时，电阻有恢复绝缘的可能性。用KH-550，KH-560，KH-570三种型号的硅烷偶联剂处理玻纤布，得到具有不同界面性能的玻纤/树脂复合材料。使用快速CAF测试方法可以观察到它们耐CAF性能不同；进一步使用层间剪切强度和纤维断裂两种不同的表征手段，研究了这些样品的界面剪切强度，发现玻纤/树脂界面的剪切强度与基板材料耐CAF性能存在显著的关联。

In recent years, with the miniaturization and high integration of electronic devices, more and more components are mounted on the surface of printed circuit board (PCB), coupled with higher processing temperatures and service voltages, the risk of failure caused by conductive anode filament (CAF) is gradually increasing, and seriously limiting the PCB application and service life. The susceptibility to CAF formation is strongly related to the entire PCB fabrication process and the properties of the substrate materials (i.e. copper clad laminates, CCL), and one of the main ways to improve the anti-CAF performance of PCB is to optimize the CCL materials, including the selection of raw materials, design of matrix/glass fiber interface, control of manufacturing process, etc., which involves a lot of testing data. However, the current standard CAF tests require long testing time, high cost, and offer little information, which cannot meet the requirements. In this work, we proposed a method for quick testing of PCB’s CAF susceptibility, which is a fast, effective, and low-cost testing tool for material development, product quality control, raw material screening, and PCB design optimization. Meanwhile, this method makes it possible to accumulate a large number of CAF data, which would provide an important reference for intelligent fabrication of substrate materials in the future.In this work, the CAF test coupon was redesigned and tested under different humidity, temperature, bias voltage. The rationality of the new design was discussed by comparing the response rules of the existing standard test coupon. The CAF test profiles were optimized and optical microscope, scanning electron microscope/energy dispersive spectrum were used to analyze the failure mode and failure mechanisms, and the effectiveness of the optimized rapid CAF test program was confirmed. It is found that the CAF may contain both pure copper and copper salts, and the dependance of electrical resistances on humidity is different for these two cases. When the former is dominant, short the insulation can not be recovered once short occurs; while the electrical resistance may recover when the latter dominates.Three types of silane coupling agents, KH-550, KH-560 and KH-570, were used to treat plain glass fiber cloth, and the glass fiber/resin composites with different interfacial properties were obtained. Their CAF performances were studied using the quick CAF test method. The interfacial shear strength of these samples was further studied by measuring the interlaminar shear strength and fiber breakage. It was found that the fiberglass/resin interfacial bonding is strongly correlated with the CAF resistance of the substrate materials.

覆铜板 可靠性 导电阳极丝 快速 CAF测 试 界面剪切强度

Copper clad laminate reliability conductive anodic filament quick CAF test interfacial shear strength

中文

独立培养

南方科技大学

王忠伟. 高性能覆铜板可靠性的快速表征方法和失效机理研究[D]. 深圳. 南方科技大学,2021.