This
simple yet elegant solution to achieving
good electrical and ground connections in
miniature high-frequency components clears
the way for lead-free package processing.Electronics manufacturing is steadily moving toward the use of lead-free packaging and lead-free printed-circuit-board (PCB) attachments. The European Union (EU) has already established Directive 2002/95/EC on the restriction of certain hazardous substances, such as cadmium, lead, and mercury, in electrical and electronic equipment. As many suppliers from the United States have recently learned, to sell in Europe, components must be suitable for lead-free electronics. In response to that need, Synergy Microwave (Paterson, NJ) has developed a simple but effective contact for its component packages that supports the use of lead-free solders and solder pastes. The company's REL-PRO® contacts and solder pads support high-integrity electrical and ground connections even when using reflow processes at lower-than-standard temperatures.
The REL-PRO® solder pads, for which a patent has been applied, feature precisely drilled via inspection holes that provide for visual inspection of solder joints. Mechanically formed with 50-mil drill bits, these via inspection holes are drilled through the package solder pads, in effect providing a window through which the integrity of reflow-solder connections can be quickly checked.
One of the difficulties in adopting current lead-free package solutions has been the high reflow temperatures needed to ensure good integrity in the solder connections. In comparison to the solder reflow temperatures typically used for tin/lead (Sn/Pb) solder connections (+260°C), the REL-PRO® packages can be assembled using +235°C lead-free solder, as well manual or automatic placement and attachment with lead-free solder pastes at +217°C.
The company plans to offer these "lead-free-ready" packages with its wide assortment of active and passive components, including attenuators, couplers, demodulators, frequency synthesizers, mixers, modulators, phase detectors, power dividers, transformers, and voltage-controlled oscillators (VCOs). According to the company's president, Meta Rohde, "We are prepared to go totally lead free with all of our components." These modified packages can be tested in existing test fixtures, with the solder via holes greatly simplifying visual inspection of assembled parts.
Of course, the move to lead-free packaging requires customer readiness to adopt a lead-free assembly process. To assist in the progression, Synergy is planning to post outline drawings of all new REL-PRO® packaged components on its website.