Complete dehydration of porous low-K material poses a major challenge to process engineers. The problem with porous low-K material is the series of deep cave-like holes that harbor moisture in an insulating material. Even when it is possible to heat the material enough to evaporate moisture on the cave walls, the steam is still present and needs to be drawn out of the cave.
Unfortunately, in a standard clean room, enough moisture exists to react with the pore walls and slowly produce a moisture layer that will reduce the K factor. However, if the pores are sealed against the ingress of moisture, integrity of the dielectric can be retained.
YES equipment uses a series of vacuum pulls and hot Nitrogen purges so the sidewalls of the pores are completely dehydrated. This way, when the atmosphere of the chamber is hot Nitrogen at 1 Torr, the atmosphere in all pores is at 1 Torr.
In order to successfully remove all moisture from porous low-K material, transform it into hydrophobic material, and seal it so it won't absorb moisture again, YES recommends using either of two ovens:
Here's an outline of the process:
NOTE: It is possible to do a copper anneal at the same time you treat the low-K dielectric and reduce process steps.
Vapor deposition can restore low-k dielectrics that are plasma (ash) damaged.
Vacuum systems such as the YES-Vertacure and YES-450PB Series are designed to meet your low-k dielectric needs. When you're ready to run a demo, just let us know. You can contact us