Profile-Free Copper Foil for High Density Wiring and High Frequency Application

摘要

Nowadays, the growth of electronic industry is remarkable. All electronic devices are getting smaller with higher performance and data transmission speed. Therefore, we have developed a new profile-free copper foil whose surface roughness (Rz) is less than 1.5 μm with satisfactory adhesion strength. A new original surface treatment of the profile-free copper foil provided affords good peel strength (0.7 kN/m or more) equivalent to that for the conventional roughened foil with sufficient reliability. With the new profile-free copper foil, the conventional subtractive method is applicable to the wiring of 60 μm pitch or less, and the short-circuit fault of electroless Ni/Pd/Au plating, which is prone to occur in fine wiring, will be restrained since the wiring is formed on a smooth surface. Moreover, the transmission loss at 5 GHz will decrease by 8 dB/m since the surface roughness of the conductor line is suppressed.