SMTA International Conference Proceedings


Characteristics of New Electroless Au/Pd/Au Process For Fine Line Application

Authors: Tetsuya Sasamura, Ph.D., Tatsushi Someya, Eriko Furuya, Katsuhisa Tanabe, Shigeo Hashimoto
Company: C.Uyemura & Co.,Ltd.
Date Published: 9/17/2017   Conference: SMTA International


Abstract: The characteristics of electroless Au/Pd/Au (IGEPIG) deposit which has been newly developed for fine line application as electroless Ni-P (EN) free, has been compared with that of conventional electroless Ni- P/Pd/Au (ENEPIG) deposit and electroless Pd/Au (EPIG) deposit.

IGEPIG deposit had excellent wire bonding reliability (WBR) compared with other deposits even if Au thickness of IGEPIG at the top surface was less than that of EPIG and ENEPIG deposit. From the results of AES analysis after heat treatment for 16 hours at 175 degree C, Pd and Cu could been hardly detected at the top surface of Au, and it indicated that IGEPIG deposit prevented Cu and Pd diffusion. Also, it was revealed by EBSD (electron back scatter diffraction pattern) analysis that Pd grain size on Au was about ten times bigger than those on Pd activated Cu surface. It was assumed that the prevention of Pd and Cu diffusion was relative with bigger Pd grain size of IGEPIG deposit.

Solder joint reliability (SJR) of IGEPIG deposit with SAC305 (Sn-3.0Ag-0.5Cu) solder ball is better than that of EPIG deposit, almost same with that of ENEPIG deposit. IGEPIG deposit had excellent pattern ability, because of no EN deposit and Pd activator process compared with ENEPIG and EPIG.

Key Words: 

Pattern ability, Wire bonding, IGEPIG, EPIG, Pd diffusion, EN free process



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