A new tool, for conventional vapour priming and image reversal, was recently installed at MSL. Image reversal is a process where exposed areas of positive resist remain after processing (thus behaving like a negative resist). This offers several advantages, such as:
- Better resolution compared to negative resist.
- Negative sidewall profile suitable for liftoff processing.
- Possibility to control sidewall profile with exposure dose.
- Possibility to get positive or negative images with the same mask independent of polarity.