Title :
High temperature degradation mechanism of conductive adhesive/Sn alloy interface
Author :
Suganuma, E. ; Yamashita, M.
Author_Institution :
Inst. of Sci. & Ind. Res., Osaka Univ., Japan
Abstract :
The Ag-epoxy conductive adhesive/Sn-10Pb coating interface was subjected to heat exposure at 150°C for up to 1000 hours and the interface degradation was examined by metallurgical analysis. Preferential Sn diffusion from the Sn-Pb coating layer to the Ag-epoxy conductive adhesive layer occurs due to heat exposure. In contrast, Ag does not show any significant diffusion. Large voids are formed in the Sn-Pb coating layer and a thin gap is formed at the Ag-epoxy/Sn-Pb coating layer interface. Ag3Sn is formed in the Ag-epoxy layer. A debonding band is formed from the free surface at the Ag-epoxy/Sn-Pb coating interface. The degradation due to heat exposure is attributed to these facts. An ideal interface structure for the Ag-epoxy/Sn alloy coating that does not lose interface connection was proposed. From the electrode, a diffusion barrier layer against the electrode is followed by a Sn alloy layer that can melt at repair temperatures, and finally a barrier layer against Ag-epoxy adhesive such as Cu or Ni is applied
Keywords :
adhesives; assembling; chemical interdiffusion; conducting polymers; diffusion barriers; environmental degradation; filled polymers; interface structure; lead alloys; metallisation; packaging; silver; surface treatment; thermal stresses; tin alloys; voids (solid); 1000 hr; 150 C; Ag; Ag-epoxy conductive adhesive layer; Ag-epoxy conductive adhesive/Sn-10Pb coating interface; Ag-epoxy/Sn alloy coating; Ag-epoxy/Sn-Pb coating layer interface gap formation; Ag3Sn; Ag3Sn formation; Cu; Cu barrier layer; Ni; Ni barrier layer; Sn alloy layer; Sn-Pb coating layer; Sn-Pb coating layer voids; SnPb; conductive adhesive/Sn alloy interface; debonding band; diffusion barrier layer; heat exposure; high temperature degradation mechanism; ideal interface structure; interface connection; interface degradation; melt temperature; metallurgical analysis; preferential Sn diffusion; repair temperature; voids; Bars; Coatings; Conducting materials; Conductive adhesives; Degradation; Lead; Metals industry; Temperature; Testing; Tin;
Conference_Titel :
Advanced Packaging Materials: Processes, Properties and Interfaces, 2001. Proceedings. International Symposium on
Conference_Location :
Braselton, GA
Print_ISBN :
0-930815-64-5
DOI :
10.1109/ISAOM.2001.916542
