Board level drop impact simulation and test for development of wafer level chip scale package

2010 ◽  
Author(s):  
Yong Liu ◽  
Qiuxiao Qian ◽  
Jihwan Kim ◽  
Stephen Martin
Keyword(s):  
Drop Impact ◽  
Wafer Level ◽  
Impact Simulation ◽  
Chip Scale Package ◽  
Board Level

Low Profile and Large Size WLCSP in IoT Applications

2019 ◽  
Vol 2019 (1) ◽  
pp. 000327-000332
Author(s):  
Tom Tang ◽  
Kuei Hsiao Kuo ◽  
Victor Lin ◽  
Kelly Chen ◽  
J.Y. Chen ◽  
...  
Keyword(s):  
High Performance ◽  
Wafer Level ◽  
Joint Reliability ◽  
Large Size ◽  
Low Profile ◽  
Chip Scale Package ◽  
Iot Devices ◽  
Small Form Factor ◽  
Board Level ◽  
Board Level Reliability

Abstract Recently, Wafer Level Chip Scale Package (WLCSP) Package is being rapidly adopted in Internet of Things (IoT) and consumer mobile electronics due to its low profile, small form factor and relatively easy assembly process. WLCSP with large die size becomes the trend in fulfilling high performance product demands. However, the solder joint reliability performances of WLCSP is the key challenge and becomes critical as increasing die size, especially the size is larger than 6 × 6 mm2. There is also growing interest in low profile WLCSP packages to less than 300 microns, especially when they are placed in a limited space inside IoT devices. Thin wafers are fragile and must be supported over their full dimensions to prevent cracking and breakage. An increasingly popular approach to thin wafer handling involves grinding and taping thin wafers with in-line machines. A specific carry tape have been also developed for transferring thin wafers after thinning. In this paper, WLCSP board level reliability for both large die size and low profile was studied, a test vehicle used for the large WLCSP package testing has 350um ball pitch and fully populated array. In addition to board level reliability test simulation and data collection, processing challenges were discussed, as well as processing solutions for thin wafer handling.

Board Level Reliability Enhancement for A Double-bump Wafer Level Chip Scale Package

2004 ◽  
Vol 1 (2) ◽  
pp. 64-71 ◽  
Author(s):  
Xiaowu Zhang ◽  
E. H. Wong ◽  
Mahadevan K. Iyer
Keyword(s):  
Solder Joint ◽  
Design Guidelines ◽  
Wafer Level ◽  
Element Analysis ◽  
Chip Scale Package ◽  
Form Design ◽  
Parametric Studies ◽  
Reliability Enhancement ◽  
Board Level ◽  
Board Level Reliability

This paper presents a nonlinear finite element analysis on board level solder joint reliability enhancement of a double-bump wafer level chip scale package (CSP). A viscoplastic constitutive relation is adopted for the solders to account for its time and temperature dependence in thermal cycling. The fatigue life of solder joint is estimated by the modified Coffin-Manson equation, which has been verified by experimental results using one of the double-bump wafer level CSP packages as the test vehicle. A series of parametric studies were performed by changing the Sn/Ag inner bump size (UBM pad size and standoff height), the eutectic Sn/Pb external solder joint size (pad size and standoff height), pitch, die thickness, and the encapsulant thickness. The results obtained from the modeling are useful to form design guidelines for board level reliability enhancement of the wafer level CSP packages.

Improving WLCSP Reliability Through Solder Joint Geometry Optimization

2013 ◽  
Vol 2013 (1) ◽  
pp. 000546-000550 ◽  
Author(s):  
Boyd Rogers ◽  
Chris Scanlan
Keyword(s):  
Solder Joint ◽  
Thermal Cycling ◽  
Printed Circuit Board ◽  
Geometry Optimization ◽  
Circuit Board ◽  
Wafer Level ◽  
Joint Geometry ◽  
Chip Scale Package ◽  
Large Platform ◽  
Board Level

The effects of solder joint geometry on wafer-level chip-scale package reliability have been studied both through simulations and board level reliability testing. In reliability tests on a 3.9×3.9mm2 die, an enhancement of nearly 2× in thermal cycling reliability was achieved by optimizing the solder joint and under-bump pad stack. In particular, undersizing the printed circuit board pad to produce a more spherical solder joint and reducing the polymer via size under the bump appear to be very important for improving thermal cycling results. Data collected here shows that joint geometry changes can be implemented without compromising drop performance. Methods learned were applied to the qualification of a 6.0×6.0mm2 die, a large platform for WLCSP applications.

Sample Preparation Challenges In WLCSP Epoxy Underfill Coating Removal

2012 ◽  
Author(s):  
Jason H. Lagar ◽  
Rudolf A. Sia
Keyword(s):  
Sample Preparation ◽  
Failure Analysis ◽  
Vital Role ◽  
Fault Isolation ◽  
Wafer Level ◽  
Chip Scale Package ◽  
Coating Removal ◽  
Customer Returns ◽  
Preparation Techniques ◽  
Mechanical Defect

Abstract Most Wafer Level Chip Scale Package (WLCSP) units returned by customers for failure analysis are mounted on PCB modules with an epoxy underfill coating. The biggest challenge in failure analysis is the sample preparation to remove the WLCSP device from the PCB without inducing any mechanical defect. This includes the removal of the underfill material to enable further electrical verification and fault isolation analysis. This paper discusses the evaluations conducted in establishing the WLCSP demounting process and removal of the epoxy underfill coating. Combinations of different sample preparation techniques and physical failure analysis steps were evaluated. The established process enabled the electrical verification, fault isolation and further destructive analysis of WLCSP customer returns mounted on PCB and with an epoxy underfill coating material. This paper will also showcase some actual full failure analysis of WLCSP customer returns where the established process played a vital role in finding the failure mechanism.

Ultra Thin Hermetic Wafer level, Chip Scale Package

2006 ◽  
Author(s):  
L. Shiv ◽  
M. Heschel ◽  
H. Korth ◽  
S. Weichel ◽  
R. Hauffe ◽  
...  
Keyword(s):  
Wafer Level ◽  
Chip Scale Package
Sign in / Sign up

Export Citation Format

Share Document