Photo Lithography

Photolithography

Purpose

The purpose of photolithographyis to deposit a layer of photoresist

on a wafer

This layer is then developed and the pattern is transferred

onto the wafer

Rinse and spin dry

Wafer Cleaning

Before applying photoresist, it is important to remove dust, dirt, and other contaminants from

the wafers

Bake after applying photoresist

Apply Photoresist

Apply photoresist evenly in a circular motion

Mask Alignment and Exposure

Masks are used to produce patterns on wafers

GLASSCr

Masks are made of glass and chromium

WAFERMETALPHOTORESIST

Shining UV light through the mask exposes some of the photoresist

PR

The photoresist that has been exposed can then be easily removed, leaving the unexposed photoresist on the wafer

Once aligned, expose to UV lightBefore exposing, align mask and wafer

Develop

Place wafer in developer to remove photoresist that has been exposed to UV light

After developing, hard-bake the wafer, and then you are ready to etch!