Growth behaviors of intermetallic compounds on the Sn-0.7Cu-10Bi-xCo/Co interface during multiple reflow

He Gao; Fuxiang Wei; Yanwei Sui; Jiqiu Qi

Materials & Design (Jul 2019)

Growth behaviors of intermetallic compounds on the Sn-0.7Cu-10Bi-xCo/Co interface during multiple reflow

He Gao,
Fuxiang Wei,
Yanwei Sui,
Jiqiu Qi

Affiliations

He Gao: School of Materials Science & Engineering, China University of Mining & Technology, Xuzhou 221116, PR China; The Jiangsu Province Engineering Laboratory of High Efficient Energy Storage Technology & Equipments Under, China University of Mining & Technology, Xuzhou, PR China; The Xuzhou City Key Laboratory of High Efficient Energy Storage Technology & Equipments Under, China University of Mining & Technology, Xuzhou, PR China
Fuxiang Wei: School of Materials Science & Engineering, China University of Mining & Technology, Xuzhou 221116, PR China; The Jiangsu Province Engineering Laboratory of High Efficient Energy Storage Technology & Equipments Under, China University of Mining & Technology, Xuzhou, PR China; The Xuzhou City Key Laboratory of High Efficient Energy Storage Technology & Equipments Under, China University of Mining & Technology, Xuzhou, PR China; Corresponding author at: School of Materials Science & Engineering, China University of Mining & Technology, Xuzhou 221116, PR China.
Yanwei Sui: School of Materials Science & Engineering, China University of Mining & Technology, Xuzhou 221116, PR China; The Jiangsu Province Engineering Laboratory of High Efficient Energy Storage Technology & Equipments Under, China University of Mining & Technology, Xuzhou, PR China
Jiqiu Qi: School of Materials Science & Engineering, China University of Mining & Technology, Xuzhou 221116, PR China; The Xuzhou City Key Laboratory of High Efficient Energy Storage Technology & Equipments Under, China University of Mining & Technology, Xuzhou, PR China

Journal volume & issue: Vol. 174

Abstract

Read online

The Sn-0.7Cu-10Bi-xCo/Co (SCB-xCo/Co) interface reaction during soldering process, and the growth and evolution of intermetallic compounds (IMCs) after multiple reflow were investigated. The experimental results indicated that the IMCs layer was successively delaminated, dissolved and aggregated during multiple reflow, and the IMCs layer was thickened with increasing reflow cycles. The results further showed that the IMCs layers of SCB/Co and SCB-0.20Co/Co interfaces were 11.19 μm and 26.27 μm thick respectively after one reflow. The scallop-shape and flat-shape IMCs layers were generated on the SCB/Co and SCB-0.20Co/Co interfaces during initial reflow. The scallop-shape IMCs layer was transformed into the flat-shape one with increasing reflow cycles on the SCB/Co interface. Co in the solder played a role of purification, and it could decrease the concentration gradient of Co atom on the IMCs/solder interface to inhibit the Co-containing compounds growth. The IMCs were stratified due to reduction of Co concentration on the SCB/Co and SCB-0.20Co/Co interfaces after reflows, respectively. With the increase of reflow cycles, the decrease of Co concentration on the interface caused IMCs obviously to be dissolved into the liquid solder, and the free-state compounds particles were reassembled and grew up under the effect of the adsorption force. Keywords: Stratification, Co concentration, Dissolution, Aggregation, Addition co, Purification

Published in Materials & Design

ISSN: 0264-1275 (Print); 1873-4197 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials
Website: https://www.journals.elsevier.com/materials-and-design

About the journal