US EPA

333370 

Journal Article 

Interfacial reaction between Sn-0.7Cu (-Ni) solder and Cu substrate 

Nishikawa, H; Jin Yu, P; Takemoto, T 

2006 

Yes 

Journal of Electronic Materials
ISSN: 0361-5235
EISSN: 1543-186X 

35 

5 

1127-1132 

The interfacial reaction between Sn-0.7mass%Cu-(Ni) solders and a Cu substrate was investigated to reveal the effect of the addition of Ni to Sn-Cu solder on the formation of intermetallic compounds (IMCs). Sn-0.7Cu-xNi solders (x = 0, 0.05, 0.1, 0.2 mass%) were prepared. For the reflow process, specimens were heated in a radiation furnace at 523 K for 60 sec, 300 sec, and 720 sec to estimate the interfacial reaction between the molten solder and Cu substrate. Then, for the aging process, some specimens were heat-treated in an oil bath at 423 K for 168 h and 504 h. The cross sections of soldered specimens were observed to measure the dissolution thickness of the Cu substrate and the thickness of the IMC and to investigate the microstructures of IMC. The results showed that, just after the reflow process, the dissolution thickness of the Cu substrate increased with the increase of Ni content in the Sn-0.7Cu-xNi solder and the thickness of the IMC between the solder and Cu substrate was the minimum in the Sn-0.7Cu-0.05Ni solder. After the aging process, the IMC grew with the increase of aging time. In the case of 0.05% Ni, the IMC thickness was the thinnest regardless of aging time. It is clear that 0.05% Ni addition to Sn-0.7Cu solder very effectively inhibits the formation and growth of the IMC between solder and Cu substrate. Electron probe microanalysis of the IMC showed that the IMC layer in the Sn-0.7Cu-Ni solder contained Ni, and the IMC was expressed as (Cu[sup]1-y[/sup],Ni[sup]y[/sup])[sup]6[/sup]Sn[sup]5[/sup]. (English) 

Lead-free solder; interfacial reaction; intermetallic compound; Ni addition; Alliage ternaire; Nickel alliage; Cuivre alliage; Etain alliage; Assemblage brasage tendre; Composé intermétallique; Morphologie; Composition chimique; Analyse sonde électronique; Dépendance temps; Microstructure; Epaisseur; Dissolution; Coupe transversale; Vieillissement; Brasage avec refusion; Structure interface; Etude expérimentale; Métal transition alliage; Composé minéral; Substrat Cu; Cu Ni Sn; Alliage CuNiSn; Ternary alloys; Nickel alloys; Copper alloys; Tin alloys; Soldered joints; Intermetallic compounds; Morphology; Chemical composition; Electron probe analysis; Time dependence; Thickness; Cross section; Aging; Reflow soldering; Interface structure; Experimental study; Transition element alloys; Inorganic compounds; Corte transverso