Tung-Han Chuang

Relationship between wettability and interfacial reaction for Sn10Ag4Ti on Al2O3 and SiC substrates

Sn10Ag4Ti filler metal possesses the advantage of low thermal stress for active brazing of ceramics. In order to clarify its brazing mechanism, the wettability and interfacial reactions for such an active filler metal on Al2O3 and SiC ceramics substrates were evaluated. It was shown that the contact angle of Sn10Ag4Ti on both ceramics decreased with the increase of temperature and heating time. The wettability of Sn10Ag4Ti on SiC substrate was superior to that on Al2O3 substrate. For all cases with better wettability, Ti was also found to aggregate more strongly at the brazing interface. In summarizing these results, it can be concluded that the wetting tendency of Sn10Ag4Ti on Al3O3 and SiC ceramics is decided by the interfacial reaction of Ti in the filler metal with the ceramic substrates.

The oxidation behavior of Ni3AlZr alloys with various zirconium contents

Abstract The oxidation behavior of Ni3Al alloys with zirconium additions was studied after long-term air exposure over a temperature range of 560–1300°C. The results showed that the penetration of oxides into Ni3AlZr alloys along the grain boundaries was caused by the formation of ZrO2. The penetration depth of the oxides increased with an increase of the zirconium content and oxidation temperature. The reaction of the oxides was controlled by oxygen diffusion in allotropic ZrO2, and the lines in the Arrhenius diagram of the reaction rate constants reflected at 1050°C. However, the penetration of oxides was not seen in the alloy without zirconium addition. Through electron probe microanalysis and X-ray diffraction, the compositions and structures of the oxides for these alloys were also determined.

An innovative annealing-twinned Ag-Au-Pd bonding wire for IC and LED packaging

An innovative annealing twinned Ag-(8-30%)Au-(0.01-6%) Pd wire for IC and LED packaging has been developed. It exhibits high thermal stability during aging at 600°C and a small heat affected zone after wire bonding. The mean failure time of this annealing twinned Ag-Au-Pd wire when stressed with a current density of 1.23 × 105A/cm2 is about double that of the conventional grained Ag-alloy wire. For packaging on Si chips with Al pads, it possesses sufficient intermetallic compounds at the initial as-bonded stage but a slow growth rate during further reliability tests. The excellent reliability of this new bonding wire has been verified in a DDRII BGA IC package and a 0605 LED package. In the LED package, this Ag-alloy wire provides the extra benefit of increasing the light output power (LOP) by about 3.2%.