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:

  1. Approach the substrate very slowly.
  2. Steady your hand by resting it on the lid and use the centre-hole in the lid to guide the cotton bud.
  3. Hold the tip of the cotton bud just above the substrate so that it is just in contact with the edge bead.
  4. "Feel" the cotton bud, which will vibrate with even the most gentle touch onto the substrate.
  5. Watch the cotton bud closely to see when the cotton bud is absorbing the ink.
  6. Try to keep the cotton bud as close to the edge of the substrate as possible.

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