Video: Edge Bead Removal During Spin Coating Using Manual Technique
This video shows how to use a cotton bud while the substrate is spinning to gently remove edge/corner beads and improve thin film quality.
There are some occasions where the second stage (high speed) spin is not desirable, for example if a solvent wash, vacuum dry or solvent annealing step is required. In these cases a more delicate technique can be used to remove edge beads, using a cotton bud to absorb excess solution while the substrate is still spinning.
For effective corner bead removal via cotton bud follow the below points:
- Approach the substrate very slowly.
- Steady your hand by resting it on the lid and use the centre-hole in the lid to guide the cotton bud.
- Hold the tip of the cotton bud just above the substrate so that it is just in contact with the edge bead.
- "Feel" the cotton bud, which will vibrate with even the most gentle touch onto the substrate.
- Watch the cotton bud closely to see when the cotton bud is absorbing the ink.
- Try to keep the cotton bud as close to the edge of the substrate as possible.