Series 16 – Episode 3 – How semiconductor test can benefit from reed relays

Reed relays are gaining traction as an essential component in semiconductor testing systems, notes King. Semiconductor tests, particularly wafer testing, require precise switching between various test conditions, and reed relays are proving invaluable in this domain.

King outlined how reed relays are used extensively in automatic test equipment (ATE), which performs functional testing and AC/DC parametric testing of semiconductor wafers. He noted: “Reed relays are crucial in this process for switching between test conditions and accurately routing results within the ATE system itself.” The relays' high transparency – low on-resistance and high off-resistance – ensures they do not interfere with test conditions, making them well-suited for semiconductor testing environments.

One of the key advantages of reed relays over other switching technologies, such as solid-state relays, electromechanical relays (EMRs), or MEMS switches, is their performance in terms of low leakage and low capacitance. King pointed out that reed relays act as "perfect mechanical switches," offering very low leakage currents when open, which is vital for applications requiring high insulation resistance and minimal power losses.

Another significant strength is their ability to handle both high and low voltages effectively. King mentioned that reed relays can switch high voltages, up to 20 times more than some EMRs and MEMS, while also being able to handle low voltages, making them a versatile choice. This performance is achieved thanks to the vacuum-sealed construction of reed relays, which ensures compactness and reliability.

Space-saving is another critical factor, especially for PCB designs in semiconductor test systems where high-density configurations are required. Reed relays offer a compact design, smaller than EMRs and some solid-state relays. King added: “Reed relays can be placed really close together, thanks to the internal electromagnetic shielding, which prevents interaction between adjacent relays.” This design advantage helps in creating high-density boards, crucial for reducing the overall size of test equipment.

The reliability of reed relays also contributes to their long-term cost-effectiveness, as they require less frequent replacement and reduce the risk of equipment downtime. This longevity is a critical advantage in semiconductor testing, where uninterrupted operations are vital. King highlighted this by saying: “When a switching device is highly reliable, it has an extended service life, which reduces the need for frequent replacements.”

Looking to the future, King believes that reed relays will continue to evolve to meet the increasing demands of semiconductor testing.

As the semiconductor industry moves towards more complex, smaller designs, the role of reed relays will likely grow. Pickering Electronics continues to innovate to ensure its relays meet emerging needs, including testing the latest 300mm gallium nitride wafers – a significant milestone in semiconductor manufacturing.

To hear more about reed relays and much more, you can listen to Electronic Specifier’s interview with Robert King on Spotify or Apple podcasts.