Advantages of Using a Vacuum to Cure Polyimides

There are five main advantages to using a vacuum oven to bake polyimides:

Cleaner Process. The vacuum is pulled from the bottom of the oven, and preheated nitrogen enters from above and goes through a restraining stainless steel flat plate filter. This induces vertical flow and the constant removal of particles from the substrate.
Uniform Solvent Evaporation. The constant vacuum and hot nitrogen mix pulls out the solvent with more efficiency. It also provides a gentle laminar flow to remove particles. (Older methods of heating polymide relied on dwell steps to allow the substrate to heat up and boil out solvent).
Consistency. Using a vacuum provides tighter control of your process. Processing conditions are very repeatable because of reduced pressure combined with temperature profile of ramp baked.
Temperature Uniformity. Using a vacuum allows an adjustable air-mixing ratio for chamber cooling to adapt the tool for best performance over a broad range of operating temperatures. (Vacuum + pre-heated nitrogen gives control of process atmosphere).
(Almost) No Oxygen. Using a vacuum achieves oxygen levels below 10ppm during processing. And the newer polyimide bake ovens all have double door seals, creating a nitrogen "buffer" between the outside atmosphere and the inside chamber. Plus, as a bonus, a vacuum process significantly reduces the amount of nitrogen flow required.

For additional information, we invite you to contact YES.