Preventing Head in Pillow Defects in Area Array ComponentsAuthors: Nandu Ranadive, Wai Mon Ma, and Daniel Buschel
Company: Jabil Circuits, Inc.
Date Published: 5/19/2015 Conference: ICSR (Soldering and Reliability)
Prevalent hypothesis says that HiP defects form when flux in the solder paste used for joining, is allowed to dry out before the joint is formed, and does not adequately remove all the oxidation from the solder ball, for instance, due to extended dwell in flux activation temperature range
One way to reduce HiP occurrence during reflow cycle is to heat the PCBA at a high ramp rate. For very thick multilayered PCBAs however, achieving high ramp rates may be very difficult, especially in localized rework situations.
This paper describes a methodical approach adopted to study the underlying causes that can lead to HiP formation. Wetting characteristics of the solder paste were studied using a wetting balance. Dynamic warpage profiles of the BGA component and the circuit board were obtained using Moiré Interferometry, for different reflow cycles. A proper selection of paste chemistry and the most optimum profile were used to make assemblies, which were then analyzed with CT Scan (3D X-ray) techniques to detect HiP type of defects. Inspection of several assemblies with CT scan has shown no presence of HiP formation.
Head in Pillow, HiP, Dynamic Warpage
Members download articles for free:
Not a member yet?
What else do you get when you join SMTA? Read about all of the benefits that go along with membership.
Notice: Sharing of articles is restricted to just your immediate work group. Downloaded papers should not be stored on an external network or shared on the internet.