Lithography
Which is a characteristic of scanner-type exposure tools?
- AThey expose the whole wafer at once
- BThey write directly without a mask
- CThey expose while moving the mask and wafer synchronously relative to a slit of light
Show answer and explanation
Answer: C. They expose while moving the mask and wafer synchronously relative to a slit of light
A scanner illuminates only a narrow slit-shaped region and exposes each shot by scanning the mask and wafer synchronously. Because only the low-aberration central part of the lens is used, large fields can be exposed with high accuracy. A tool that exposes a whole shot at once while stationary is called a stepper.