Assembly of Cu Wirings with Ultrasmooth and High-Adhesive Electroless Cu Seed Layer by Using UV Modification and Low Attenuation of High-Frequency Transmission Property
| Autor: | Masaya Toba, Kazuyuki Mitsukura, Takashi Masuko, Nobuhito Komuro, Kazuhiko Kurafuchi, Shuji Nomoto, Shinichiro Abe |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science Computer Networks and Communications business.industry Attenuation 020206 networking & telecommunications 02 engineering and technology 01 natural sciences Electronic Optical and Magnetic Materials Printed circuit board Semiconductor Transmission (telecommunications) Ball grid array 0103 physical sciences 0202 electrical engineering electronic engineering information engineering Optoelectronics Adhesive Electrical and Electronic Engineering business Layer (electronics) |
| Zdroj: | Journal of Microelectronics and Electronic Packaging. 17:45-51 |
| ISSN: | 1551-4897 |
| Popis: | Semiconductor packages for high-performance devices with printed circuit boards having multiwiring layers such as flip-chip ball grid array have been attracting the attention to realize ultrare-liable and low-latency communications in 5G networking. Cu wirings for the package are usually fabricated by via formation by laser for dielectric, desmear, electroless Cu seed formation, photoresist patterning, electrolytic Cu plating, resist stripping, and seed layer etching. Although a desmear process can obtain enough adhesion between dielectric and Cu seed layer by anchoring effect to secure reliabilities, the interface between dielectric and Cu seed layer should be smooth to achieve low attenuation of electric signals at high frequencies. Here, instead of a desmear process, we applied a UV modification for the surface of dielectric to realize a smooth and high-adhesive seed layer against dielectric. We obtained .8 kN/m of peel strength between dielectric and Cu seed layer in spite of surface roughness of the dielectric being 45 nm by a nanolevel anchoring effect at the UV-modified layer. Because of the smooth interface by UV modification, the S21 value of microstrip line was 26% improved compared with that assembled through the desmear process at 60 GHz. |
| Databáze: | OpenAIRE |
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