Lateral scanning “Structured-Illumination-MAcroscopy” for high speed electronic inspection

With Structured-Illumination Microscopy (SIM), technical surfaces can be measured with a depth uncertainty down to 10nm and a high angular dynamical range up to +/- 70°. Specular as well as rough surfaces can be measured. SIM is well suited for the 3D inspection of micro contacts in the electronics industry. The real challenge is to measure with a demanded speed of 40cm2/sec. This cannot be achieved by just geometrical up-scaling of SIM to "SIMA"(Structured Illumination MAcroscpy), because an objective with high NA, high lateral resolution, and at the same time big field is extremely expensive. The alternative, field stitching, requires an impractical stop-and-go, which cannot be sped up arbitrarily. As a solution for these problems, we present a new SIMA that is fast and cost efficient: We replace the stop-and-go stitching by a continuous lateral scan. The trick is to scan along a direction parallel to the sample surface with a tilted reference plane. So we avoid the stop-and-go for the lateral scan and the necessity of a z-scan. The measurement speed is only limited by the speed of the camera, not anymore by mechanics. We demonstrate measurement examples.