February 22, 2006 – NEC Corp. has developed what it claims is the world’s smallest fiber-optic electric field probe, to be used for evaluating electrical characteristics inside high-density LSI packages.

Increased operating speeds and packaging density of electronic devices has created a growing problem of electromagnetic noise, which can be countered by evaluating characteristics of LSIs mounted on printed circuit boards (not the evaluation of unpackaged LSIs) and reflecting the obtained results on the circuit design.

Conventional probes, however, are too big to get into microscopic crevices such as near the solder ball between a ball grid array LSI package and a PCB, or the space among different chips in a system in package (SiP).

NEC’s answer is a probe with a 125µm-diameter optical fiber and electro-optical film, lead zirconate titanate, formed at the edge of the fiber to act as a field sensor. Converting an electrical signal to an optical signal in the film means the wave guide has no metallic parts to disrupt the electromagnetic field around the device, thus eliminating measurement inaccuracies.

The probe was created in cooperation with AIST, partially supported by a New Energy and Industrial Technology Development Organization (NEDO) project, Nano Structure Forming for Advanced Ceramic Integration Technology, within the Japan Nanotechnology Program.