DocumentCode :
3073988
Title :
First-principles calculations of structural and elastic properties of hexagonal Cu2In intermetallic compound
Author :
Hsien-Chie Cheng ; Ching-Feng Yu ; Wen-Hwa Chen
Author_Institution :
Dept. of Aerosp. & Syst. Eng., Feng Chia Univ., Taichung, Taiwan
fYear :
2012
fDate :
24-26 Oct. 2012
Firstpage :
240
Lastpage :
242
Abstract :
In recent years, Pb-Sn solders have been commonly applied in the microelectronic packaging industry over last decades due to their remarkable properties, such as good wetting, low melting temperature and low cost. Nevertheless, because of the toxic Pb element in the solders, significant environmental and health issues are created. Due to the high environmental awareness, green electronics products are presently advocated and proclaimed through legislation [1]. It has been extensively reported that multi-component Pb-free solders are potential to be the substitute of the Pb-Sn solders for developing green products. In recent years, extensive thermodynamic database of some metal elements, such as Ag, Cu, In, Sn, and Zn, has been established by many studies in replace of Pb to synthesize a novel Pb-free solder alloy [2]. The In-based solders could be one of the favorable candidates due to their good wetting, thermal fatigue durability, high ductility and appropriate melting point. However, there are some significant technical challenges needed to be resolved prior to their full and successful implementation and application. For example, Cu has been widely utilized in the under bump metallurgy (UBM) of chip and substrate metallization for solder bonding in the microelectronics industry. Because of the active chemical diffusion characteristics, it tends to diffuse into Sn-In based solder during assembly process and isothermal aging testing to form several intermetallic compounds (IMCs) at the interfaces between the solder and UBM, such as Cu2In. The IMCs can induce a great influence on the structural stiffness and material strengths of solder joints, which are essential to the reliability performance of the electronic packaging. In literature, extensive focuses have been placed on the interfacial formation and evolution of the Cu2In IMC by many researches. It should be noted that the success of application of the Pb-free solder in the advanced inte- connect technology strongly relies on the full comprehension of the mechanical properties of the IMC. Unfortunately, only limited studies have been attempted to explore the essential subject in literature. Thus, the main goal of the study attempts to provide a more complete and comparative investigation of the structural and elastic properties of the Cu2In IMC through first-principles calculation by density functional theory (DFT) [3] within the generalized gradient approximation (GGA) [4] based on pseudopotential method. It is believed that through the investigation of its elastic properties, one can have a better understanding of its relation to the thermal-mechanical reliability of solder joints.
Keywords :
assembling; copper alloys; density functional theory; ductility; durability; environmental legislation; gradient methods; indium alloys; integrated circuit bonding; integrated circuit metallisation; integrated circuit packaging; integrated circuit reliability; melting point; metallurgy; solders; thermal stress cracking; wetting; Cu2In; DFT; GGA; IMC; UBM; active chemical diffusion characteristics; assembly process; density functional theory; ductility; elastic property; environmental awareness; first-principles calculation; generalized gradient approximation; green electronics product; hexagonal intermetallic compound; interconnect technology; isothermal aging testing; legislation; material strength; melting point; microelectronic packaging industry; microelectronics industry; multicomponent Pb-free solder; pseudopotential method; reliability performance; solder bonding; solder joint; structural property; structural stiffness; substrate metallization; thermal fatigue durability; thermal-mechanical reliability; thermodynamic database; under bump metallurgy; wetting; Approximation methods; Crystals; Educational institutions; Lattices; Mechanical factors; Metals; Soldering;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT), 2012 7th International
Conference_Location :
Taipei
ISSN :
2150-5934
Print_ISBN :
978-1-4673-1635-4
Electronic_ISBN :
2150-5934
Type :
conf
DOI :
10.1109/IMPACT.2012.6420284
Filename :
6420284
Link To Document :
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