Technical Library | 2019-05-24 09:22:59.0
There is a smaller process window and a much narrower margin of error when creating and using lead-free reflow profiles for surface mount parts on printed circuit boards (PCBs). Solder balls, dewetting, tombstones, voids, and head-on-pillow problems will occur much more frequently because lead-free alloys behave differently than eutectic pastes. Problems are compounded due to the extra heat necessary for some lead-free pastes to reach their melting points.
Technical Library | 2023-09-05 21:00:53.0
The head on pillow defect is becoming more common. This paper describes one such occurrence for an OEM and explains how it was dealt with. In this particular case it was solved by application of problem solving skills by the OEM, component supplier and the solder paste provider
Technical Library | 2022-12-23 20:44:54.0
One of the upcoming reliability issues which is related to the lead-free solder introduction, are the headin-pillow solderability problems, mainly for BGA packages. These problems are due to excessive package warpage at reflow temperature. Both convex and concave warpage at reflow temperature can lead to the head-in-pillow problem where the solder paste and solder ball are in mechanical contact but not forming one uniform joint. With the thermo-Moiré profile measurements, this paper explains for two flex BGA packages the head-in-pillow. Both local and global height differences higher than 100 µm have been measured at solder reflow temperature. This can be sufficient to have no contact between the molten solder ball and solder paste. Finally, the impact of package drying is measured
Technical Library | 2010-03-04 18:11:53.0
While the electronics manufacturing industry has been occupied with the challenge of RoHS compliance and with it, Pb-free soldering, established trends of increasing functionality and miniaturization have continued. The increasing use of ultra-fine pitch and area-array devices presents challenges in both printing and flux technology. With the decrease in both the size and the pitch of said components, new problems may arise, such as head-in-pillow and graping defects
Technical Library | 2017-04-06 16:50:56.0
Silicon photonics is an IC technology where data is transferred using light that is routed on the chip using optical waveguides (Figure 1). Silicon photonics is best known as a method to solve problems with high input/output bandwidth applications. For example, because of ever-growing bandwidth requirements in datacenters, the optical transmit and receive heads are being placed closer and closer to the board and the IC. But, designers also apply this technology to biosensors, medical diagnostics, and environmental monitoring. Regardless of the application, photonic ICs always need integration to electronic circuits and this results in unique challenges.
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