电子封装完整性超声无损检测与表征

The electronic package which has been widely used nowadays is usually under thermal cycling environment so that the temperature field and thermal stress field changing circularly can produce the stress fatigue inside of it. A variety of defects such as micro-cracks, delamination and voids will appear while local fatigue stress is over the maximum of allowed stress because the electronic package is composed of multilayer and inhomogeneous materials. vicious cycling speeds up the failure of electronic packages. It is significantly important to check out the defects of electronic package in the process of quality control and overhaul of electronic system.. Scientific issues followed are the principle of defects growth inside electronic package under thermal cyclic environments, the principle of quantitative ultrasonic nondestructive testing of multi-morphologic defects in electronic packages and the failure pattern of electronic package caused by multi-morphologic defects development.. Research is involved with interactivity between discontinuous thermal diffusion and thermal stress field in inhomogeneous and anisotropic layered medium, and growth principle and coupling influence of different morphologic defects affected by thermal and stress filed. It also include the interaction between nonlinear ultrasonic wave propagation and multi-morphologic defects, and distinguish ability of quantitative compensation and amendment for different defects. It’s also concerned the failure rule of electronic package propelled by location of multi-morphologic defects, and ultrasonic characteristics model and verification approach about electronic package failure prediction. . The project will constitute a characterization theory of electronic package integrity by ultrasonic nondestructive testing eventually.

微电子封装已广泛应用，处于热循环工作环境，封装内温度场和热应力场也在循环变化，易产生应力疲劳；电子封装是层状非均质粘合结构，当局部疲劳应力超过材料强度极限时，导致封装内部出现微裂纹、分层和空洞等缺陷，恶性循环，加速了电子封装失效；在质量检验和电子系统检修对封装缺陷及时检测和失效预测具有重要意义。.研究的科学问题是，热循环对封装结构缺陷扩展影响规律、封装结构缺陷量化超声无损检测机理和不同形态缺陷对封装结构失效的影响规律。.研究涉及层状非均质各向异性多元介质内的非连续热传导与热应力场的相互作用、温度场和热应力场作用于不同形态缺陷扩展与耦合作用；多层非均质结构内非线性超声波动规律与不同形态缺陷对超声传播的影响、不同形态缺陷超声检测分辨能力和量化补偿和修正；不同形态缺陷对封装不同部位失效的影响规律、电子封装结构失效预测的超声特征模型和验证方法。.最终形成电子封装结构失效的超声无损检测及预测理论。

近几年，“核心电子器件、高端通用芯片及基础软件产品”、“极大规模集成电路制造装备及成套工艺”、“新一代宽带无线移动通讯网”、“高分辨率对地观察系统”、“载人航天与探月工程”以及“大型飞机”等国家科技重大专项已陆续启动实施，许多专项电子设备成功与否是与高端电子器件结构制造的可靠性有着密切关系的，与电子封装结构缺陷的无损检测与失效预测科学的发展是密不可分的，因此，电子封装结构失效预测的表征理论研究将会对国家相关重大专项的研究起到积极推动作用，对提高极大规模集成电路等高端器件的质量和可靠性具有重要意义；同时，随着近年来国际微电子制造企业逐步向中国的迁移，中国制造高端电子器件的能力越来越强，其制造质量和服役可靠性保障都离不开电子封装结构完整性检测和失效预测的诸多基础理论。.本项目针对电子封装结构缺陷的无损检测和失效预测需求，重点开展了高频超声传播理论、高频超声显微扫查检测方法、以及电子封装结构损伤超声无损检测与评估理论等研究；取得了如下重要成果：提出了多层介质高频超声传播与微小缺陷超声检测的模型，建立了高频聚焦换能器声场的点源-高斯声束模型，揭示了高频聚焦声束在液体、液/固、固/固界面耦合关系，揭示了高频超声传播的频散规律，形成了高频超声无损检测基本理论；揭示了高频超声换能器的透镜传播规律，发现了新型高频超声换能器声透镜材料，即用蓝宝石替代石英材料，提高了信噪比和频响特性，提高了高频超声无损检测分辨力；针对电子封装多层异种材料粘接结构特点，建立了高频超声TOF与频域成像算法，实现了对电子封装层状结构与特性的三维可视无损检测与表征，建立了电子封装内部热疲劳裂纹的无损检测方法，揭示了电子封装内部热疲劳裂纹的生长与扩展规律，实现了对电子封装热疲劳与力学损伤的评估和预测。项目在研期间，发表了一批与研究内容相关的论文；获批多项省部级科技进步奖；申请或授权了一批发明专利；立项和制定颁布了多项国家标准；出版1部专著。