What is drop casting?

Make a bubble of liquid on top of a surface then either

1. Spin the chip on a spinner, or

2. Wait 30 seconds and rinse with clean solvent, or

3. Wait until on all solvent evaporates (this will leave drying spots, non-uniform coverage)

In chemistry, the dropcast method is commonly understood to be the latter (no. 3), pipetting a compound dissolved in solvent onto a surface and left to dry. As stated previously, non-uniform coverage and small volumes make repeatability an issue.