Zhendong Wang , Jiaojiao Yang , Jikang Yan , Biao Wang , Chongyan Leng , Linyan Zhao
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引用次数: 0
Abstract
The majority of studies on high-reliability solder alloys have focused on the six-element system of Sn, Ag, Cu, Bi, Sb, and Ni. However, there is limited research on the influence of Co element within this system. In this study, a Sn3.0Ag0.5CuBiSbNixCo (x = 0 wt%, 0.02 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%) alloy (referred to as SACBSN-xCo alloy) was prepared using a melting method. The mechanical properties of SACBSN-xCo alloy solder joints were evaluated through ultimate shear strength testing. The composition analysis of the alloy, phase composition examination, intermetallic compound (IMC) investigation and interfacial layer morphology analysis were conducted using ICP, XRD, SEM and EDS techniques respectively. Furthermore, the evolution process of solder structure and solder joint interface layer under different aging times was observed in detail. Results indicate that with the addition of Co element in the alloy solder system two heat release peaks appear during the solidification process; specifically when adding 0.05 wt% Co element content to the mixture it reduces supercooling degree by 15.17 °C to only 1.03 °C; Moreover wettability improvement can be achieved to some extent when adding either 0.02 wt% or 0.05 wt% Co content. The addition of trace Co can inhibit the excessive growth of IMC in the solder alloy matrix and refine the alloy structure. It can promote the growth of Cu6Sn5-based IMCs and inhibit the growth of Cu3Sn layer in intermetallic compound layer (IMCs). In addition, the mechanical properties and thermal fatigue stability of the solder joints are steadily improved by Co element. After adding Co element, the shear strength of the alloy solder joint is increased by about 14.84 %. After aging at 150 °C for 25 days, the shear strength of SACBSN-xCo alloy solder joints is increased by about 20.4 %, which significantly improves the thermal fatigue stability of the solder joints after high temperature aging treatment. The results show that when Co content is 0.05 wt%, the alloy solder has better comprehensive properties.
期刊介绍:
Microelectronics Reliability, is dedicated to disseminating the latest research results and related information on the reliability of microelectronic devices, circuits and systems, from materials, process and manufacturing, to design, testing and operation. The coverage of the journal includes the following topics: measurement, understanding and analysis; evaluation and prediction; modelling and simulation; methodologies and mitigation. Papers which combine reliability with other important areas of microelectronics engineering, such as design, fabrication, integration, testing, and field operation will also be welcome, and practical papers reporting case studies in the field and specific application domains are particularly encouraged.
Most accepted papers will be published as Research Papers, describing significant advances and completed work. Papers reviewing important developing topics of general interest may be accepted for publication as Review Papers. Urgent communications of a more preliminary nature and short reports on completed practical work of current interest may be considered for publication as Research Notes. All contributions are subject to peer review by leading experts in the field.