Development of typical process histories and statistical performance
Since higher volume production often means large substrates with multiple devices manufactured in parallel (similar to the IC industry) the measurement and understanding of spatial variation is a fundamental necessity. To this end, a number of 10 cm diameter test parts were formed with a grid pattern and then measured using optical interferometry. The grid included both device level (0.5 cm) features and channel level features (~10 micron). Although these tests were carried out on a very precise nanoimprinting machine, significant variation was found along transverse lines across the part, as shown in Figure 1. This variation is being analyzed at three scales to determine the origin of the variation: Substrate or machine scale, individual device scale and fine feature scales.
Figure 1. Measured height variations of test features across a 10 cm PMMA embossed part.