Hot embossing of a sine-grid for a surface encoder

This paper describes the replication of a precision sinusoidal grid surface, which is used as the measurement reference of a surface encoder for nanometrology of multi-axis positions. The profile of the gird surface is a superposition of sinusoidal waves in the x-direction and the y-direction with spatial wavelengths on the order of 100 μm and amplitudes on the order of 100 nm. The area of the surface is on the order of several tens of millimeters to hundreds of millimeters. The aluminum master surfaces were fabricated on a diamond turning machine equipped with a fast tool servo, which has advantages of high accuracy and good surface finish but time-consuming for fabricating micro-structures over a large area. Replication from the master surface was then carried out for fast fabrication. Hot embossing was chosen as the replication method. Experiments of replication on polymer films were conducted.