Dynamic Electroluminescence Imaging (DEI) is a technique used to observe semiconductor devices as they operate. Much like a traditional oscilloscope, the technique delivers waveform information that is useful for assessing the operation of the circuits that comprise a device. It can be thought of as a non-contact “optical oscilloscope probe”. The technique has two major advantages over traditional electrical oscilloscope probing. The technique is noninvasive and has a theoretical bandwidth approaching 100 GHz. This means that very fast signals can be observed without unduly loading or otherwise interfering with the circuitry under test. Moreover, the characterization of signals at individual nodes along a signal path allows problems that arise from intervening interconnects and transmission lines to be identified. This paper will show several examples of the radio frequency (RF) measurement capabilities of this technique that have been demonstrated in our laboratory.

Dynamic electroluminescence imaging (DEI) is a noninvasive means of obtaining high-resolution timing information from a CMOS circuit. This article reports timing measurements made on a 512K-bit EPROM enabled by the use of optical methods alone. The equipment to observe DEI is comprised of a Karl Suss probe station equipped with a position dissecting photomultiplier tube called a MEPSICRON. To demonstrate the power of the technique a 512Kbit EPROM in ~1 micron technology was prepared for DEI Measurement. The EPROM circuitry was exposed for DEI measurement by decapsulating the part with acids. DEI images are recorded in the region of the tri-state drivers for bond pads D0 through D3 and in the region of bond pad D0. The results demonstrate timing information with up to 11 ps time resolution that is correlated with the chip circuitry. DEI has obvious applications in performance evaluation, failure analysis, intellectual property evaluation, and prototype testing.