Bandwidth Foundry International has embarked upon exposing wafers using an ASML pas 5500/100 i-line stepper for the manufacturing process. The wafer is coated with a photosensitive polymer which is exposed and developed to provide a patterned wafer ready for the next step in the process chain. Exposure of the wafer, unlike a traditional mask aligner where the whole wafer is exposed at one time, is a step and repeat process printing the pattern (die) repeatedly across the wafer. A photomask or reticle is designed to be reduced in print size by a 5 to 1 ratio, which also has the added advantage of smoother features on the wafer. The major advantage of using the stepper multiples is that a wafer can be exposed more quickly and easily with smaller and smoother features, e.g. such as a microchip for a mobile phone.
