SILICON OPTICAL CIRCUIT FOR DETECTING FLAWS IN AN OPTICAL CIRCUIT ELEMENT BASED ON LIGHT TRANSMITTANCE CHARACTERISTICS

摘要

The visual detection of a silicon optical circuit in the prior art depended on the sensory judgment of a human being to visually recognize, and there were limits to completely performing the detection of small scratches. A defective chip having scratches overlooked by visual inspection is mistakenly judged as passing and flows outs to a step downstream from the visual inspection. Unable to judge the defective chip as failing at the stage of an early step of the overall optical circuit, yield was lowered in downstream production and inspection steps, and production inspection costs for products increased. This optical circuit, in addition to an optical circuit that achieves a desired function, includes a detection optical waveguide for scratches sufficiently close to an optical waveguide of the optical circuit that surrounds the entire optical circuit, and a grating coupler connected to the detection optical waveguide. It is possible to efficiently discover scratches within each chip in a wafer state prior to being cut into chips, on the basis of the measurement of transmission characteristics of the detection optical waveguide using the grating coupler. It is also possible to discover scratches hierarchically by providing an individual detection waveguide for each chip and further forming one common detection optical waveguide over a plurality of chips.