2段階レーザ焼結法を用いた銅マイクロ粒子レーザ焼結膜の高密度化に関する研究

抄録

The forming wiring process by utilizing the laser sintering instead of conventional subtractive process, has been gathering attention from the point of view of environmentally friendly as well as simplifying manufacturing process. We have been attempted to form Cu wiring on the liquid crystal polymer substrate with low dielectric constant by one-step laser-sintering with the wavelength of 532 nm. In this study, to form the bulk-like Cu film with high conductivity, we employed two-step laser-sintering of Cu microparticles introducing laser-preheating process. In order to densify copper film, It is crucial to separate removing organic residue in the coated Cu films and sintering process of Cu microparticles. Using Fourier Transform Infrared Spectroscopy, we clarified that Cu film after conventional drying process contains some organic residue which impedes sintering of Cu microparticles. The resulting Cu copper film applied two step sintering exhibited densified structure with Cu grain boundaries molten, and the low specific residence of 11.7 μΩ·cm. Densification of the laser-sintered Cu films results in enhancing the conductivity of the Cu wire.