Video: Demonstration of the Edge Bead Problem When Spin Coating With High Boiling Point Solvents
This video demonstrates how edge beads can remain on your substrate after spin coating with viscous solutions or high boiling point solvents.
At low spin speeds, the middle of the substrate often dries significantly quicker than the edge of the substrate. In some cases the edge of the substrate may take minutes to dry. Even if the edges of the substrate have been designed not to contain any active/critical components, the edge/corner bead may spread back towards the middle when spinning has stopped. This can ruin the film quality. Also, when spin coating viscous solutions such as photoresist, the increased thickness at the edges may prevent good alignment of subsequent shadow masks.
Watch the videos on edge bead removal to find out how to solve this problem:
For More Tips and Techniques
- To achieve high quality spin coated films, visit our Spin Coating Guide.