The Importance of Cabling in Probe Stations for High Frequency 5G Applications
Masaru Omoto, Junkosha
Probe stations allow a user to position electrical, optical or RF probes on a silicon wafer and connect them to a Vector Network Analyzer (VNA) so that the device can be tested. Using high-end cabling in a probe station is crucial: cables must be low loss, lightweight and both phase and amplitude stable against temperature, flexure and vibration. This is because once calibrated, the cable must function accurately for a long period of time. If the cable is not phase stable, it can quickly degrade a system, producing inaccurate data and requiring regular re-calibration.
Though armoured cables can improve amplitude and phase stability, they are generally considered too heavy for probe stations as they are incompatible with the positional sensitivity of the probe tips and can offset the system mechanics if moved incorrectly. A further important consideration is the connectors, which help to keep the probe tip (which requires micrometer accuracy) stable. Many applications require bending in the cable, which makes the angle of the connector crucial in ensuring the probe tip is kept in position.
According to research by Industry Today, the global high-frequency probe station market will be worth $1176.3 million by 2025, rising from $793.8 million in 2019. This expansion is primarily being driven by an increase in 5G deployment.
Indeed, since the first specifications for 5G were unveiled in 2017, the development of the technology has evolved at considerable speed. In the US, Verizon launched its 5G mobile network at the start of April 2019, making it the first carrier to offer this next-generation network for widespread use. By the end of 2019, Verizon 5G covered 31 cities across America.
As 5G continues to be rolled out, applications requiring high quality ICs increase and so the need for probe stations to test chips packaged together rises in importance. Indeed, in wafer probe testing, chips are mounted together and tested for functionality as a complete solution. With chips operating at higher frequencies, cables must transfer the signals on to and out of the chips at a faster rate. To meet this requirement, good quality cables are essential. Many cable manufacturers use a wrapped dielectric so that is more stable with bending and movement of the cable such as Junkosha’s cabling that uses ePTFE tape wrapped dielectric layer, which can be controlled for tension, thickness, mechanical ability and flexibility.
Some cable manufacturers are specializing in cables optimized for probing stations such as Junkosha’s MWX001 cable assembly that features low insertion loss for measuring applications requiring flexibility. Cable insertion loss is minimized due to its cable structure, which is optimized for measurement up to 110 GHz. A Safety-Lock mechanism is available to ensure that the 1.0mm(m) connector pin is inserted into the female connector safely and surely.
Alongside radar, space and defense sectors, the key application area for these types of cables is 5G. Bringing reduced latency and improved data rate, 5G is designed to interconnect devices, machines, and people closer than ever before – known as the Internet of Things. This enables a future of advanced technology including autonomous vehicles, smart cities, and virtual reality – each bringing more sophisticated chipsets and thus increasing the requirement for efficient probe station testing and high-end cabling. To find out more about MWX001, please visit: https://www.junkosha-mwx.com/special_products/special_products001.php.