Browsing by Author "Liang, MW"

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Electroless copper/nickel films deposited on AIN substrates
(2004-12-01)
Liang, MW
;
Hsieh, TE
;
Chen, CC
;
Hung, YT
;
材料科學與工程學系
In this work, we studied the application of electroless copper/nickel (Cu/Ni) films deposited on aluminum nitride (AlN) substrates to high-frequency power GaAs device packaging. Experimental results showed metal films deposited on polished AlN surfaces possess a flatter surface, a finer grain structure, and a lower resistivity than those on unpolished surfaces. On unpolished AlN substrates, rough-surface-induced voids appear in the film interface during grain clustering, therefore deteriorating the electrical conductivity of the deposited layers. Pull-off tests revealed that the Cu/Ni films strongly adhered on both types of AlN substrates and that the adhesion strength exceeded 761 kg/cm(2). The Ni film remained a mixture of amorphous and microcrystalline structures, and the Cu film was polycrystalline. The resistivity of the Cu/Ni film was decreased by annealing process, which in turn decreased the number of crystal defects in the films. Subsequent Pb-Sn solder bumping experiments indicated the amorphous Ni(P) film was a good diffusion barrier layer since Sn could not diffuse through it.
Thin-film reactions during diffusion soldering of Cu/Ti/Si and Au/Cu/Al2O3 with Sn interlayers
(2003-09-01)
Liang, MW
;
Hsieh, TE
;
Chang, SY
;
Chuang, TH
;
材料科學與工程學系
The multilayer thin-film systems of Cu/Ti/Si and Au/Cu/Al2O3 were diffusion-soldered at temperatures between 250degreesC and 400degreesC by inserting a Sn thin-film interlayer. Experimental results showed that a double layer of intermetallic compounds (IMCs) eta-(Cu0.99Au0.01)(6)Sn(5/)delta-(Au0.87Cu0.13)Sn was formed at the interface. Kinetics analyses revealed that the growth of intermetallics was diffusion-controlled. The activation energies as calculated from Arrhenius plots of the growth rate constants for (Cu0.99Au0.01)(6)Sn-5 and (Au0.87Cu0.13)Sn are 16.9 kJ/mol and 53.7 kJ/mol, respectively. Finally, a satisfactory tensile strength of 132 kg/cm(2) could be attained under the bonding condition of 300degreesC for 20 min.