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

fYear

1994

fDate

1-4 May 1994

Firstpage

590

Lastpage

594

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, σ_p=σ_ae^-kP, is established to relate the shear strength, σ_p, 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;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronic Components and Technology Conference, 1994. Proceedings., 44th

Conference_Location

Washington, DC

Print_ISBN

0-7803-0914-6

Type

conf

DOI

10.1109/ECTC.1994.367616

Filename

367616