Title :
Porosity formation and its effects on mechanical properties of SMT solder joints
Author :
Xie, D.J. ; Chan, Y.C. ; Lai, J.K.L. ; Hui, I.K.
Author_Institution :
Dept. of Electron. Eng., City Polytech. of Hong Kong, Kowloon, Hong Kong
Abstract :
This paper mainly describes pore formation characteristics in surface mount solder joints and its effect on joint strength. Two PCB boards with 14-lands on each board are used in shear strength test. Several solder pastes and reflow temperature profiles are chosen for the experiments. Porosity in solder joints is detected by X-ray radiographic inspection and its area fraction measured quantitatively by computer image analysis. From this work, it is found that pore formation has a great effect on the shear strength. Different solder pastes and reflow temperature profiles may cause different pore formation and joint strength of solder joints. The area fraction of pores in tested solder joints varies from 0 to 20%, and their shear strengths change from 40 to 17 MPa correspondingly. The expression, σp=σae-kP, is established to relate the shear strength, σp, to the area percentage of porosity, P, in surface mount solder joints
Keywords :
X-ray applications; circuit reliability; inspection; porosity; printed circuit manufacture; radiography; reflow soldering; shear strength; surface mount technology; PCB boards; SMT solder joints; X-ray radiographic inspection; area fraction; computer image analysis; joint strength; mechanical properties; pore formation characteristics; porosity formation; reflow temperature profiles; shear strength test; solder pastes; Inspection; Mechanical factors; Radiography; Soldering; Surface-mount technology; Temperature; Testing; X-ray detection; X-ray detectors; X-ray imaging;
Conference_Titel :
Electronic Components and Technology Conference, 1994. Proceedings., 44th
Conference_Location :
Washington, DC
Print_ISBN :
0-7803-0914-6
DOI :
10.1109/ECTC.1994.367616
