PAS 5500 60

A lithography stepper projects a mask pattern onto photoresist-coated substrates. A stepper exposes one field at a time and repeats that field across the substrate. An i-line stepper belongs to the optical lithography stage used to define patterns before development and pattern transfer.

A stepper illuminates a reticle and images that pattern through projection optics onto resist. The substrate stage moves between exposures so the same reticle field can be repeated across the substrate. Alignment in this class of tool registers each new exposure layer to patterns already formed on the substrate.

Photolithography steppers are used after substrate preparation and photoresist coating. Photolithography steppers expose the resist pattern that will later be developed. After exposure, the substrate typically moves to post-exposure bake, development, and then to etch, deposition, implant, or lift-off flows depending on the process being built.

I-line steppers are used to form repeated optical patterns for semiconductor and microfabrication processes. Tools in this class can support front-end device layers, back-end interconnect layers, and a range of patterning tasks in research and specialty process work. Such tools are also used on transparent or compound substrates when the resist and optical stack are compatible with the exposure wavelength.