预紧力对超声换能系统振动特性影响规律研究

【作者】 刘炜；

【导师】 吴运新；

【作者基本信息】 中南大学 ， 机械工程， 2010， 硕士

【摘要】 半导体器件制造是国家各支柱产业发展的基础,是发展国民经济、信息与安全、民用与军用电子产品等领域的关键。当前,包括单点引线与多点倒装的超声键合构成半导体器件的主要封装形式。换能系统是在超声键合工艺与装备的核心执行机构,其动力学特性直接决定键合质量。全篇论文以提高芯片键合质量为目标,主要讨论了换能系统中PZT压电陶瓷受一维压应力对超声能量传递效率与动力学特性的影响规律等理论与技术问题,并对键合工具与换能杆的连接预紧力对换能系统动力学特性影响进行了分析。本文通过用有限元分析软件ANSYS对换能器进行有限元建模,仿真得到换能系统的振动模态和换能系统谐响应与时间历程的响应曲线,并利用阻抗测试仪、多普勒测速仪验证有限元分析的结果。本文的研究工作主要集中在：1.论述了当前换能器的发展情况以及其存在的问题,查阅大量文献资料,对压电陶瓷PZT的非线性力电耦合特性进行了描述,压电陶瓷在一维压应力的作用下的本构特征参数变化规律是本文进行有限元分析的基础。2.利用有限元分析软件ANSYS建立换能系统的有限元模型,研究换能系统的模态与响应动力学特性。在概括压电材料结构有限元方法的理论基础上,利用有限单元法构建[压电陶瓷-过渡段-变幅杆-键合工具-界面]整个系统的动力学仿真模型,研究系统固有振动特性与响应行为,仿真计算获得换能系统的工作主模态。3.分析后盖板预紧力、劈刀与变幅杆连接预紧力对超声换能器振动模态的影响规律。4.分析劈刀与变幅杆连接预紧力对换能系统谐响应和瞬态响应的影响规律。5.介绍了换能器的阻抗测试方法,并采用阻抗分析仪扫频测试换能器谐振频率验证仿真结果。利用非接触式激光多普勒测振仪实验获得换能器变幅杆末端的振动位移和振动速度。以上研究内容、方法与结论,对理解、分析与设计芯片键合换能系统具有积极作用。更多还原

【Abstract】 IC Packaging is the development foundation of all main industries, and is the key factor for developing other domains such as economy, safe guard and electronic products in our China. Nowadays, ultrasonic bonding, which including wire bonding and thermosonic flip chip bonding, are the main packaging processes for manufacturing semiconductor products. The transducer system is the key working actuator in bonder, and its characteristics of ultrasonic energy propagation and vibration in bonder, and its characteristics of ultrasonic energy propagation and vibration influence the bonding quality. The whole work is aimed for improving the bonding quality, in which the ultrasonic energy propagation in the system, the dynamic characteristics effected by pre-stress are discussed. This article through managing ANSYS simulation obtain the vibration mode of transducer system, and analyze the effect of transducer when the pre-tighten force is considered or not, and validate the result through finite element analysis with Impedance equipment. The study of this paper mainly bases on:1. The currently development and problem of the ultrasonic transducer. is dissertated in this paper, the nonlinear piezoelectric ceramic PZT-electrical coupling characteristics under compressive stress are described, the conformation changes of characteristic parameters in one-dimensional piezoelectric ceramics is the basis of the finite element analysis。 2. The theoretic model of ultrasonic energy propagation of transducer system is established based on equivalent method. The impedance/admittance model includes all parameters such as materials, size, frequency and load. Based on the model, the frequency and impedance of transducer system are calculated numerically, and the result are verified by experiments.3. The affection of pre-stress for the transducer back slab and mounting style is analyzed. The model analysis effected by the pre-stress between bonding tool and ultrasonic horn is constructed.4. Finite Element Harmonic analysis and Transient analysis are researched by changing the pre-stress between bonding tool and ultrasonic horn.5. Impedance test of transducer system is introduced in this paper, and the analysis result with Impedance equipment testing transducer system is validated. The ultrasonic energy of different directions for transducer system are attained by laser Doppler vibrometer.All above research contexts, methods and conclusions will help to understand, analyze and design the ultrasonic transducer in IC bonding.更多还原