Impact of the PCB design on the crack risk of CSP assemblies subjected to temperature cycling and drop tests

Author(s):  
H. Fremont ◽  
M. Mura ◽  
B. Plano ◽  
W. Horaud ◽  
Y. Danto
2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Jia Xi ◽  
Xinduo Zhai ◽  
Jun Wang ◽  
Donglun Yang ◽  
Mao Ru ◽  
...  

FeNi alloy is considered a possible substitute for Cu as under bump metallization (UBM) in wafer level package (WLP) since it forms very thin intermetallic compound (IMC) layer with Pb-free solder in the reflow process. In this paper, WLPs with FeNi and Cu UBM were fabricated and their board level reliabilities were studied comparatively. The WLP samples assembled on the printed circuit board (PCB) were subjected to temperature cycling and drop tests according to JEDEC standards. The results showed that the reliability of WLP with FeNi UBM was a little lower than that with Cu UBM. The main failure modes for both FeNi and Cu UBM samples in temperature cycling test were the crack in IMC or solder ball on PCB side. And detachments between UBM and the redistribution layer (RDL) were also observed in Cu UBM WLPs. In drop test, the crack of RDL was found in all failed FeNi UBM samples and part of Cu UBM ones, and the primary failure mode in Cu UBM samples was the crack of IMC on PCB side. In addition, the finite element analysis (FEA) was carried out to further understand the difference of the failure modes between the FeNi UBM samples and the Cu UBM samples. The high stress was observed around the UBM and the pad on PCB in the temperature cycling model. And the maximum stress appeared on the RDL in the drop simulation, which was obviously larger than that on the pad. The FEA results showed that the introduction of FeNi UBM increased the stress levels both in temperature cycling and drop tests. Thus, the FeNi alloy cannot simply replace Cu as UBM in WLP without further package structural optimization.


2000 ◽  
Vol 28 (1-2) ◽  
pp. 219-223 ◽  
Author(s):  
Keith Friedman ◽  
Fiona Gaston ◽  
Jack Bish ◽  
Donald Friedman ◽  
Anthony Sances, Jr.
Keyword(s):  

Author(s):  
So-yeon Kim ◽  
Jung-eun Yoo ◽  
Da-hyun Woo ◽  
Bo-young Jung ◽  
Bo-ram Choi

Author(s):  
Ramesh Varma ◽  
Richard Brooks ◽  
Ronald Twist ◽  
James Arnold ◽  
Cleston Messick

Abstract In a prequalification effort to evaluate the assembly process for the industrial grade high pin count devices for use in a high reliability application, one device exhibited characteristics that, without corrective actions and/or extensive screening, may lead to intermittent system failures and unacceptable reliability. Five methodologies confirmed this conclusion: (1) low post-decapsulation wire pull results; (2) bond shape analysis showed process variation; (3) Failure Analysis (FA) using state of the art equipment determined the root causes and verified the low wire pull results; (4) temperature cycling parts while monitoring, showed intermittent failures, and (5) parts tested from other vendors using the same techniques passed all limits.


2017 ◽  
Vol 43 (6) ◽  
pp. 5080-5088 ◽  
Author(s):  
Hiroyuki Miyazakia ◽  
Shoji Iwakiri ◽  
Kiyoshi Hirao ◽  
Shinji Fukuda ◽  
Noriya Izu ◽  
...  

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