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AUGUST 2021 I PCB007 MAGAZINE 99 X-ray Void Evaluation X-ray analysis was performed on the plat- ed laser-drilled panels to confirm void-free fill performance in the through-holes. e X-ray image for 200 µm thick and 90–100 µm diame- ter through-holes is shown in Figure 12. Void- free fill was seen in the through-holes. Conclusion rough-hole fill process for filling mechan- ically-drilled and laser-drilled through-holes spanning a wide range of through-hole diam- eters and panel thicknesses was demonstrated. e plating was carried out by a one bath/one step process where bridging is achieved using a phase-shi pulse waveform followed by filling the via formed using DC. is process of filling the through-holes in one bath rather than two offers significant benefits to fabricators in the form of increased throughput and easier main- tenance of the plating bath. Void-free fill was achieved in the through-holes as confirmed by X-ray analysis. PCB007 Acknowledgements This work was performed in collaboration with our DuPont Interconnect Solutions colleagues in North America, Asia, and Europe. We sincerely thank them for their help and support. Figure 12: Void-free fill as seen in X-ray image of filled laser-drilled through-holes. Psyche orbits the sun in the asteroid belt, a do- nut-shaped region of space between Earth and Ju- piter that contains more than a million rocky bodies that range in size from 10 meters to 946 kilometers in diameter. With a diameter of more than 200 km, Psyche is the largest of the M-Type asteroids, an enigmatic class of asteroids that are thought to be metal rich and therefore potentially may be fragments of the cores of proto-planets that broke up as the solar system formed. Studying such relatively tiny objects that are so far away from Earth (Psyche drifts at a distance that ranges between 179.5 and 329 million km from Earth) poses a significant challenge to planetary sci- entists, which is why NASA plans to send a probe to Psyche to examine it up close. Typically, thermal observations from Earth—which measure the light emitted by an object itself rather than light from the sun reflected off of that object—are in infrared wavelengths and can produce only 1-pixel images of asteroids. That one pixel does, however, reveal a lot of information; for example, it can be used to study the asteroid's thermal inertia, or how fast it heats up in sunlight and cools down in darkness. (Source: Caltech) Observatory in Chile Takes Highest-Resolution Measurements of Asteroid Surface Temperatures Ever Obtained From Earth Millimeter-wavelength emissions reveal the temperature of the asteroid Psyche as it rotates through space.

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