Purpose

Low-Ag SAC solder will lead to a series of problems, such as increased the melting range and declined the solderability and so on. These research studies do not have too much impact on the improvement of solders’ performance but were difficult to achieve satisfactory results. It is urgent to develop new soldering technology to avoid the bottleneck of lead-free solder. low-temperature-stirring soldering and ultrasonic-assisted soldering was developed in the authors’ early work, but slag inclusion and pore would gather and grow up to lead decreasing of the shear strength. In this paper, Cu/SAC0307 +Zn power/Cu joints with ultrasonic-assisted at low-temperature was successfully achieved.

Design/methodology/approach

45um Zn-powder and SAC0307 No.4 solder powder were mixed to fill the Cu-Cu joint, and the content of Zn-powder were 0 and 5%, 7.5% and 10%, 12.5% and 15% respectively. During the soldering process under ambient atmosphere %252C the heating platform provided a constant 220%253 F and the ultrasonic vibrator applied a constant pressure of 4 MPa to the copper substrate. The soldering process was completed after holding 70 s at 300 W.

Findings

The Zn particles made the IMC at the joint interface and in the soldering seam from scallop-type Cu₆Sn₅ to flat-type Cu₅Zn₈. The shear strength of joints without Zn was only 12.43 MPa, the shear strength of joints with 10% Zn reached a peak of 34.25 MPa, and the shear strength of joints containing 10% Zn was 63.71% higher than that of joints without zinc particles, and then the shear strength decreased. In addition, with the increase of zinc content, the fracture mode of the joint changed from the brittle fracture of the original layered tears to the mixed tough and brittle fracture.

Originality/value

A new method that Zn micron-size powders and SAC0307 micron-size powders was mixed to fill the joint, and successfully achieved micro-joining of Cu/Cu under ultrasonic-assisted without flux at low-temperature.

中文翻译：

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低温超声辅助下锌粉含量对Cu/SAC0307粉/铜接头性能的影响

目的

低银SAC焊料会导致熔程增大、可焊性下降等一系列问题。这些研究对焊料性能的提高没有太大影响，但难以取得满意的结果。迫切需要开发新的焊接技术，以避免无铅焊料的瓶颈。作者早期的工作中开发了低温搅拌焊接和超声波辅助焊接，但夹渣和气孔会聚集和长大，导致剪切强度降低。本文成功实现了低温超声辅助下Cu/SAC0307+Zn粉末/Cu接头。

设计/方法/方法

将45um Zn粉和SAC0307 No.4焊粉混合填充Cu-Cu接头，Zn粉含量分别为0%和5%、7.5%和10%、12.5%和15%。在环境气氛 %252C 下的焊接过程中，加热平台提供恒定的 220%253 F，超声波振动器向铜基板施加 4 MPa 的恒定压力。在 300 W 下保持 70 秒后完成焊接过程。

发现

Zn 颗粒在接合界面和焊缝中形成了从扇贝型 Cu ₆ Sn ₅到扁平型 Cu ₅ Zn _{8 的}IMC 。不含锌的接头剪切强度仅为12.43 MPa，含10% Zn的接头剪切强度达到峰值34.25 MPa，含10% Zn的接头剪切强度比不含锌颗粒的接头高63.71%，然后剪切强度下降。此外，随着锌含量的增加，接头的断裂方式由原来的层状撕裂的脆性断裂转变为韧脆混合断裂。

原创性/价值

一种将Zn微米级粉末和SAC0307微米级粉末混合填充接头的新方法，成功实现了超声辅助下无助焊剂低温下Cu/Cu的微连接。