【作者】 李战慧；

【导师】 吴运新；

【作者基本信息】 中南大学 ， 机械电子工程， 2010， 博士

【摘要】 热超声芯片键合是当前芯片一级封装使用的主要技术。其中,超声键合换能系统是超声芯片键合工艺的核心执行机构。键合换能系统接触界面在工作过程中的非线性特性严重影响了超声波在换能器中的传播效率和芯片键合的质量。本课题受高等学校博士点专项科研基金：芯片封装换能系统接触界面的超声波传播机理及其设计(编号：20060533068)项目和国家自然科学基金：超声波在键合换能系统接触界面的传播机理与低能耗接触界面设计(编号：50605064)项目支持。本文以提高超声芯片键合的质量和键合过程的稳定性为目标,以提高超声波在键合换能器接触界面传递效率为核心,研究超声波在键合换能器接触界面传播的能量传递效率规律、波形畸变以及高次谐波产生规律等,从根本上认识超声波在键合换能器接触界面处非线性传播的机理,为热超声键合换能器的优化设计、制造和使用提供理论依据。本文主要的研究内容：第一、采用赫兹接触原理与斯涅尔定律,构建了超声波在键合换能器接触界面的传播模型。研究接触界面因素：介质材料特性阻抗、表面粗糙度、实际接触面积、接触界面应力和界面粘合剂等对超声波在接触界面传播的影响规律。建立超声波在接触界面传播的非线性方程,运用约化摄动法求解,得到超声波在键合换能器接触界面的传播方程。基于超声波在接触界面的传播特性,建立了超声波在键合换能器接触界面传播的弹簧阻尼质点模型。第二、运用机械动力学原理,将超声波在换能系统接触界面的传播模拟成弹簧阻尼质点系统,仿真得到超声波振动在键合换能器接触界面的传播随接触界面预紧力、接触界面刚度和接触界面阻尼的影响规律。在超声键合试验台上验证了不同接触界面因素：表面粗糙度、接触界面应力和界面粘合剂对超声波传播的影响规律。试验得到了超声波在接触界面的波形畸变、高次谐波产生与键合强度之间的联系。第三、采用等效电路方法,构建了超声键合换能系统接触界面的等效阻抗模型。基于力电类比方法,建立了接触界面包含接触界面材料、接触界面状态参数的阻抗和导纳集总参数模型。完善了超声键合换能器的等效电路模型。采用阻抗分析仪验证了换能器等效电路模型的正确性。得到了接触界面应力、接触界面粗糙度及界面粘合剂对超声换能器谐振频率和阻抗特性的影响规律。以上研究内容、方法与结论,对理解、分析超声键合换能器的非线性振动具有积极的作用,对超声键合换能器接触界面的理解和提高与推进半导体器件制造起着基础性的意义,对其他超声换能系统也具有一定的借鉴意义。更多还原

【Abstract】 Thermosonic chip bond technology is a potential process in the current chip package area. Ultrasonic bond transducer system is the important part in ultrasonic chip bond process. The nonlinear characteristics of contact interface in ultrasonic bond transducer system are mainly factor of ultrasonic transmission efficiency reduction and chip bond failure. This thesis comes from Research Fund for the Doctoral Program of Higher Education of China, Ultrasonic Propagation Mechanism in Contact Interface of Chip Package Transducer System and Design, No.20060533068 and National Natural Science Foundation of China, Ultrasonic Propagation Mechanism in Contact Interface of Chip Package Transducer System and Low Power Consumption Contact Interface Design, No.50405064. In order to improve the ultrasonic transmission efficiency at the contact interface of ultrasonic transducer and the quality of chip bond and stability of transducer vibration, the thesis study on ultrasonic transmission at the contact interface of the ultrasonic bond transducer. Ultrasonic energy loss, waveform conversion and harmonic variation are studied. The nonlinear vibration fundamental of contact interface is important for the ultrasonic transducer optimize design, manufacture and use.In this paper, the study consists of:Firstly, based on Hertz contact theory and Snell law, the model of ultrasonic propagation through contact interface was studied. The factors of contact interface including:interface roughness, the actual contact area, contact interface stress and interface adhesive. The relation of the factors affecting on ultrasonic propagation was obtained. The nonlinear ultrasonic propagation equation is established, and is solved using reductive perturbation method. The spring-damp-mass model of ultrasonic propagation through contact interface is established, in the light of ultrasonic propagation chracteritics at contact interface.Secondly, ultrasonic propagation through contact interface is simulated using of mechanical dynamics simulation software. It is gained that ultrasonic propagarion varys with the contact interface stress, contact interface stiffness and interface damp. The test is done on ultrasonic bond platform. The contact interface roughness, contact interface stress and interface adhesive are taken account. It is abtained that the waveform distortion and high harmonic generation is relating to contact interface parameters. The relation of the bonding strength and the higher order harmonics of bond tool vibration are obtained.Finally, the equivalent impedance model of ultrasonic transducer’s contact interface is established using of mechanical and electrical equivalent model. Based on electromechanical analogy method, the contact interface model is established, which concludes contact interface material, contact interface status parameter. The equivalent impedance model of ultrasonic transducer is gained. The model is proved is validatied by experiment using impedance analysis method. The content of the above research, methods and conclusions have a positive effect on understanding contact transducer interface’s nonlinear vibration of ultrasonic transducer. Those are help for analysis and design of chip bonding transducer system. It plays a fundamental significance that improving the manufacture of semiconductor devices. There are some references on other ultrasonic transducer system.更多还原