Solder composition for electronic devices
View Patent ↗Each of junctions formed between a semiconductor device and a substrate comprises metal balls of Cu, or other materials and compounds of Sn and the metal balls, and the metal balls are bonded together by the compounds.
1. A semiconductor module comprising a substrate having an electrode, a chip component mounted on said substrate and a semiconductor chip mounted on said substrate, wherein said chip component is connected to said electrode with a solder bonding material, said solder bonding material being substantially free of lead (Pb) and comprising an intermetallic compound, an amount of unreacted solder on a periphery of said intermetallic compound, and a plurality of copper (Cu) balls disposed in said intermetallic compound, said intermetallic compound having a melting point higher than that of said solder.
2. A semiconductor module according to claim 1 , wherein said intermetallic compound includes Cu 6 Sn 5 .
3. A semiconductor module according to claim 2 , wherein said intermetallic compound further includes Cu 3 Sn.
4. A semiconductor module according to claim 2 , wherein said plurality of Cu balls each has a diameter ≧5 μm.
5. A semiconductor module according to claim 1 , wherein said module comprises an RF module.
6. A semiconductor module according to claim 1 , wherein said module comprises one of a SAW element, a power amplifier module, or a module for monitoring a Li battery.
7. A semiconductor module according to claim 1 , wherein said chip component comprises a chip resistor or a chip capacitor.
8. A semiconductor module according to claim 1 , wherein at least one of said Cu balls is connected to said electrode of said substrate by said intermetallic compound.
9. A semiconductor module according to claim 1 , wherein both of said Cu balls and said intermetallic compound have a melting point greater than 260° C.
10. A semiconductor module according to claim 1 , wherein each of said Cu balls consist substantially entirely of copper.
11. A semiconductor module according to claim 1 , wherein said solder includes Sn and said intermetallic compound includes a CuSn compound.