If caps over a deposited film are not hermetic, later processing steps may interact with the film and change its properties through gaseous interactions.

“So you may rule out a material because of something as simple as that. Uh, more complex, uh, challenges might be, uh, the subsequent processing may have gaseous interactions with downstream steps.”

“So for example, I've deposited the film, I've capped it with other materials, but they're not hermetic, and so my third or fourth or fifth step in the process may actually still interact with it and change its properties.”