ZESTRON, the global leading provider of high precision cleaning products, services, and training solutions in the electronics manufacturing and semiconductor industries, is pleased to release the whitepaper “Critical Cleaning Requirements To Overcome Advanced Packaging Defluxing Challenges”
Whitepaper Abstract:
As technology advances, wafer-level packages have emerged in many different varieties. Computing
has evolved significantly over the years. Chips integrated with additional functionalities to improve
performance, processing challenges, storage and networking has become standard. The
development of the packages such as SiP, fcBGA, PoP, 2.5D, etc. which utilizes multiple or larger die
sizes, increased bump counts, lower standoff height and a large variety of components on the
packages have reduced the effectiveness of cleaning. The common packaging interconnect is using
solder and die attached to a substrate by a solder reflow process. The flux residues after soldering
pose a cleaning challenge, especially underneath these extremely low-profile components. As
standoff height reduces, flux residues have less area to outgas during reflow. Typically, the standoff
height is <100µm and it continues to shrink further. For some components such as QFNs, LGAs, the
large thermal pad at the center of the component body poses barriers to the complete removal of
the flux residues. Partially removed or untouched residues can lead to reliability failures as
consequences of electrochemical migration and dendrite growth as well as electrical leakage
currents. Effective cleaning improves product reliability by ensuring optimal condition for subsequent
processes, such as wire bonding, underfill and molding. This paper discusses the breakthrough in
cleaning challenges for advanced packaging, especially when addressing factors like high density
assemblies, latest flux formulation and low standoff heights. The most common cleaning system used
for cleaning advanced packaging substrate is a conveyorized spray-in-air inline cleaning system. The
discussion extends to how effectively the cleaning process needs to be balanced, in terms of
chemical, mechanical and thermal energies. We will also explore the key cleaning parameters that
lead to successful removal of flux residues from underneath the low-profile components. For
example: nozzle types, spray pressure, chemical exposure time, cleaning temperature and type of
cleaning agent. We will conclude with several customer case studies to validate the above findings.
To request for this free whitepaper, please click the link here: Request free whitepaper
For more information about Zestron, please email us at infoasia@zestron.com