The solder joint and runner metal reliability of wafer-level CSP (Omega-CSP)

2002 ◽  
Author(s):  
In-Soo Kang ◽  
Jong-Heon Kim ◽  
I.S. Park ◽  
Ki-Rok Hur ◽  
Soon-Jin Cho ◽  
...  
Keyword(s):  
Solder Joint ◽  
Wafer Level

Solder Joint Reliability Study for Wafer Level Packages on Flexible and Rigid Boards

2013 ◽  
Vol 2013 (1) ◽  
pp. 000039-000044
Author(s):  
Gary Gu ◽  
Jon Chadwick ◽  
Daniel Jin
Keyword(s):  
Solder Joint ◽  
Parametric Design ◽  
Low Cost ◽  
Wafer Level ◽  
Solder Joint Reliability ◽  
Conformal Coating ◽  
Joint Reliability ◽  
Chip Size ◽  
The Right ◽  
Elastic Plastic Materials

Applications of Wafer Level Packages (WLPs) have shown tremendous growth in the rapid developing smartphones and other portable electronic devices. The technology trends lead to smaller chip size, low cost, and more integrated functions, but also face higher reliability requirements due to the reduced number of solder bumps as well as smaller bump size and height. New assembly technologies such as flexible phone board and conformal coating also brought up new thermo-mechanical reliability challenges. Based on 3D finite element modeling, the current studies focus on solder joint reliability of WLPs and compared between flex based and traditional rigid based WLP assemblies. Conformal coated and underfilled WLPs as well as some bump parameters are also studied. The parametric studies were carried out in ANSYS and all models were created by using APDL (ANSYS Parametric Design Language) scripts. Each simulation starts from stress free status set at solder reflow temperature and were subjected to thermal cyclic load between −40 and +125°C with ramp and dwell time. Creep strain was considered for solder alloys and kinematic plastic hardening was considered for other elastic-plastic materials. The solder fatigue life is estimated by using modified Coffin-Manson equation and was compared with available thermal cycling test data. The results show that underfill is still the most effective option and conformal coating can play an important role if the right material is selected. Bump parameters such as height, which have certain effects on the solder reliability on WLP-on-Rigid, have limited impact on WLP-on-Flex assembly.

Solderability and Reliability of Sintered Nano-Ag Bond Pads of Printed Re-Distribution Layer (RDL)

2021 ◽  
Author(s):  
S. W. R. Lee ◽  
J. C. C. Lo ◽  
X. Qiu ◽  
N. Tu
Keyword(s):  
High Temperature ◽  
Solder Joint ◽  
Wafer Level ◽  
Joint Reliability ◽  
Ball Shear Test ◽  
Alternative Approach ◽  
High Temperature Storage ◽  
Bond Pads ◽  
Photolithography Process ◽  
Temperature Storage

Abstract Re-distribution layer (RDL) is one key enabling technology for advance packaging. RDL is usually fabricated in wafer level by photolithography process. An alternative approach for implementing RDL by additive manufacturing (AM) method is proposed in this study. This allows RDL to be fabricated on singulation chip. Nano-silver (nano-Ag) ink is printed on the silicon chip to form routing traces and bond pads. However, the Ag pad may be consumed by solder quickly if the process is not properly controlled. This paper studied the effect of nano-Ag ink sintering condition on the solderability of Ag pad. The solder joint mechanical integrity was evaluated by solder ball shear test. High temperature storage test was also carried out to evaluate the solder joint reliability. Experiment results showed that Ag pad fabricated by AM is SMT compatible. High temperature storage did not cause early failure to the samples. There was not significant change in the Ag3Sn IMC layer thickness and mechanical strength. The finding of the present study will serve as a very useful reference for future practice of forming solder joints on sintered nano-Ag pads.

Board level solder joint reliability analysis of a fine pitch Cu post type wafer level package (WLP)

2008 ◽  
Vol 48 (4) ◽  
pp. 602-610 ◽  
Author(s):  
Xiaowu Zhang ◽  
Vaidyanathan Kripesh ◽  
T.C. Chai ◽  
Teck Chun Tan ◽  
D. Pinjala
Keyword(s):  
Solder Joint ◽  
Reliability Analysis ◽  
Wafer Level ◽  
Solder Joint Reliability ◽  
Joint Reliability ◽  
Fine Pitch ◽  
Board Level ◽  
Wafer Level Package
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