Title :
Effects of heating factors on the geometry size of unrestricted lead-free joints
Author :
Fengshun, Wu ; Li, Chen ; Boyi, Wu ; Yiping, Wu
Author_Institution :
Huazhong Univ. of Sci. & Technol., Wuhan, China
Abstract :
In this paper, the effects of heating factor on the geometry size of unrestricted lead-free joints were investigated. The morphologies of IMC formed in the joint were studied in detail by using SEM and EDX. When the Sn3.5Ag0.5Cu solder joint was formed in unrestricted condition, the width of the joint and the mean thickness of interfacial IMC increased with the increase of heating factor. The volume of the joint was larger than the volume of the Sn3.5Ag0.5Cu solder, but the effects of heating factor on the change of volume were undulate. The morphologies of the interfacial IMC were needle-like when heating factor was small, and then, grew, coarsened when heating factor increased. The tensile fractography of the joint indicated that the morphologies of IMC at fracture surface were various. Some of IMCs shaped like pyramid, and some of IMCs shaped like needle. And part of the fracture surface located in the solder, and part of the fracture surface located at the interface between the interfacial IMC and solder.
Keywords :
X-ray chemical analysis; chemical interdiffusion; copper alloys; flip-chip devices; fracture; interface structure; optical microscopy; reflow soldering; scanning electron microscopy; silver alloys; solders; surface mount technology; tin alloys; EDX; SEM; SnAgCu; diffusion-barrier; flip chip; geometry size; heating factors; interfacial microstructure; interfacial morphologies; intermetallic compound; optical microscopy; packaging; reflow processing; solder joint; surface mount; tensile fractography; unrestricted lead-free joints; Bars; Copper; Environmentally friendly manufacturing techniques; Geometry; Heating; Lead; Morphology; Soldering; Surface cracks; Temperature;
Conference_Titel :
Asian Green Electronics, 2004. AGEC. Proceedings of 2004 International IEEE Conference on the
Print_ISBN :
0-7803-8203-X
DOI :
10.1109/AGEC.2004.1290874
