Quantitative description method for Bi segregation degree at Sn-Bi solder interface based on addition of alloying element M

Abstract

The invention discloses a quantitative description method for Bi segregation degree at a Sn-Bi solder interface based on addition of an alloying element M, and belongs to the technical field of microelectronic interconnection materials. By calculating two parameters of diffusion activation energy and segregation energy, the improvement effect of the added alloying elements on Bi segregation is quantitatively evaluated theoretically. finally, the accuracy of the method is evaluated by taking parameters such as bond strength and bond length among metal bonds of Sn-Bi, Sn-M and Bi-M, charge transfer conditions of M and surrounding Sn and Bi and the like as auxiliary verification parameters. Through the method, an important reference basis is provided for designing and preparing the Sn-Bi welding flux doped with a small amount of alloy elements to solve the Bi coarsening problem caused by Bi segregation at the interface in the future, the experiment workload is reduced, the research efficiency is improved, and the method has high practical value.

Description

technical field [0001] The invention belongs to the technical field of microelectronic interconnection materials, and in particular relates to a method for quantitatively describing the degree of Bi segregation at the interface of Sn-Bi solder based on the addition of alloying element M. Background technique [0002] The microelectronics industry is an important industry that promotes technological progress and economic development around the world. With the continuous development of the microelectronics industry, microelectronic interconnection materials are used as materials for connecting electronic components and substrates, and between components and components. , which plays a vital role in realizing the function and reliable operation of electronic products. Tin-lead (Sn-Pb) solder has long been widely used as a microelectronic interconnection material in electronic packaging due to its low production cost, favorable operating temperature, and good mechanical properti...

AI Technical Summary

Problems solved by technology

However, the enrichment of Bi phase segregation in the packaging process is a key issue affecting the reliability of Sn-Bi solder connections, which in turn affects its wide application in the field of electronic packaging.

For the Sn-58Bi alloy, segregation of Bi at the solder-substrate interface was observed, forming a Bi-rich layer which is brittle in nature and will lead to a decrease in the mechanical properties of the solder

[0004] Although the existence of interfacial Bi-rich phases in Sn-Bi solders has been observed experimentally, the underlying mechanism of Bi segregation is still unclear, and it is impossible to explore effective methods to improve the enrichment of Bi phase segregation.

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