RDL Automated System
VertaCure Series (automated wafer handling)
YES ovens are designed to give total parameter control over your process, in a clean environment. Wafers placed in a YES high temperature vacuum oven stay clean, so you get the results you want. YES ovens provide an ideal processing environment for curing:
Low-K dielectrics - Polyimide
- BCB
- Copper anneal
Process Benefits
Pulling a vacuum in a series of nitrogen purge cycles removes oxygen, moisture and atmospheric contaminants. Running at 250 Torr (1/3 of atmosphere) gently draws out solvents in a gentle vertical laminar flow that removes particles. Processing at reduced pressure prevents a problematic heat reaction, in which a hard skin forms on the top of polyimide film before it is completely baked and traps solvents.
1. 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. Plus, as a bonus, a vacuum process significantly reduces the amount of nitrogen flow required compared to atmospheric ovens.
2. 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 polyimide relied on dwell steps to allow the substrate to heat up and boil out solvent).
3. 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.
4. 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).
5. (Almost) No Oxygen. Using a vacuum achieves oxygen levels below 10ppm during processing. All of our polyimide bake ovens have double door seals, creating a nitrogen "buffer" between the outside atmosphere and the inside chamber.