Presto Engineering will be showcasing its capabilities to provide high volume testing of semiconductor devices up to 100 GHz and beyond, at European Microwave Week, in Madrid, Spain (23-28 September 2018).
Applications that use GHz frequencies, i.e. millimeter wavelengths (mm-Wave), are increasing rapidly and thus driving the need for high volume device testing. For example, Internet over satellite connections, car ADAS systems, and other high-speed, data transfer solutions have a projected volume of more than a billion units by 2020.
Most commercial test equipment does not test above 50 GHz and the cost of buying equipment for testing such high frequencies can be very expensive. The current method used by most customers is in-house bench testing by hand which is very slow. To solve this problem, Presto has created custom interfaces that step the test frequencies down into the range that commercial testers operate in. This enables them to provide a cost-effective testing service for ultra-high frequency or mm-Wave devices and builds on their existing services for high-frequency device testing.
Another challenge of mm-Wave devices is that the substrate used is often much more brittle than the usual CMOS, such as Gallium Arsenide or Gallium Nitride. As a result, the wafers are much more susceptible to breakage in transit and handling. To reduce the possibility of breakage, they are usually cut into quadrants once manufactured. A broken quadrant means fewer damaged parts compared to a whole broken wafer. However, the standard handling and test equipment are designed for circular wafers so Presto has developed its own quadrant handling adapters for its test equipment. On top of this, it is also key to be able to maintain a good correlation during the test and during the self-heating of the pulsed test methods, where continuous wave measurement is normally used. In this case, all the fixturing has to be able to control temperature and heat dissipation as well as include RF systematic error compensation for the measurements and maintain the correct reproducibility during production.
Among mm-Wave applications already implemented or under consideration are short-range wireless backhaul, connecting small cell wireless; data center interconnect (DCI) for cloud servers; radar, primarily automotive; body scanners for airport security; chip-to-chip communications on printed circuit boards where even short runs of wires or cables attenuate signals at these frequencies; and wireless communication protocols, such as 5G cellular, WiGig (802.11ad) and Wireless HD. For convenience, the markets can be divided into three segments: communications, automotive and cellular/consumer, which includes estimates of the potential served available market (SAM) and unit volumes. Communications, driven by expansion in small cell backhaul and cloud computing, has annual unit volumes for 2020 projected to be in the millions; and automotive, driven by assisted driving (with autonomous driving on the horizon), with projected volumes in the tens of millions. The third vertical segment, cellular/consumer, driven by WiGig and 5G mobile, is in development now with 2020 annual unit volumes projected to exceed one billion.
