CAREER: Novel Environmentally-Benign Solders for Electronic Packaging: Thermomechanical Behavior and Characterization

0092530Chawla这个职业项目在散装和小长度尺度上研究新型、环保的焊料。该研究计划包括实验研究以及有前途的Pb-Sn钎料替代合金（Sn-Cu、Sn-Ag和Sn-Ag- cu）的力学行为和微观结构的计算建模。微观结构的演变，包括焊料微观结构的粗化和焊料/衬底的相互作用，在蠕变和热疲劳行为方面进行了研究。微观结构的演变是使用新的、微观结构集成的、面向对象的有限元方法（OOF）来建模的，这种方法最近由美国国家标准与技术研究所（NIST）开发。新的微力学测试技术将被开发出来，以表征焊接球水平的热力学行为。传统的有限元技术，使用精确测量的本构行为源自微观力学测试，将用于开发寿命预测方法。此外，还将通过亚利桑那州立大学少数族裔工程学生办公室（OMEP）和女性科学与工程项目（WISE）实施一项外展计划。高中教师将在PI的实验室度过一个夏天，以获得尖端研究的经验。此外，来自工业界的兼职学生将参加新的和修订的课程，涉及电子封装材料的主题，包括焊料的物理和机械冶金。鉴于铅锡焊料在电路板制造和组装中的广泛应用，新型无铅焊料的开发和可靠性对于在电子系统中成功替代这些材料至关重要。英特尔、摩托罗拉和安森美半导体等本地公司对无铅焊料的主题非常感兴趣，并期望在整个职业发展计划过程中与行业密切互动。相信教育推广工作将有助于增加主修材料科学的本科生人数。鉴于微电子封装行业对具有材料背景的工程师的高需求，这一点尤为重要。* * *

0092530Chawla This CAREER program examines novel, environmentally benign solders in bulk form and at small length scales. The research plan includes experimental investigations coupled with computational modeling of the mechanical behavior and microstructure of promising Pb-Sn solder replacement alloys (Sn-Cu, Sn-Ag, and Sn-Ag-Cu). The role of evolution of microstructure, including coarsening of the solder microstructure and solder/substrate interactions, is examined with respect to the creep and thermal fatigue behavior. The evolution of microstructure is modeled using the novel, microstructure-integrated, Object Oriented Finite Element Method (OOF), recently developed at the National Institute for Standards and Technology (NIST). Novel micromechanical testing techniques will be developed to characterize thermomechanical behavior at the solder ball level. Conventional FEM techniques, using accurately measured constitutive behavior derived from micromechanical testing, will be used to develop life prediction methodologies. In addition, an outreach program will be implemented through the Office for Minority Engineering Students (OMEP) and the Women in Science and Engineering (WISE) program at Arizona State University. High school teachers will spend a summer in the PI's laboratory to gain experience with cutting edge research. Also, part-time students from industry will take part in new and revised courses dealing with the subject of materials for electronic packaging, including physical and mechanical metallurgy of solders. %%%Given the widespread use of Pb-Sn solder in the manufacture and assembly of circuit boards, the development and reliability of new Pb-free solders is crucial for the successful substitution of these materials in the electronic systems. The subject of Pb-free solders is of great interest to local companies such as Intel, Motorola, and Onsemiconductor and close interaction with industry is expected throughout the course of this career development program. It is believed that the education outreach effort will contribute to an increase in the number of undergraduate students majoring in materials science. This is particularly important given the high demand for engineers with materials backgrounds in the microelectronic packaging industry. ***