Parylene Deposition Process
The parylene polymers are deposited from the vapor phase by a process which in some respects resembles vacuum metalizing. Unlike vacuum metallization, however, which is conducted at pressures of 10-5
Since parylene is non-liquid, it does not pool, bridge, or exhibit meniscus properties during application. No catalysts or solvents are involved, and no foreign substances are introduced that could contaminate coated specimens.
In contrast to parylene, the thickness of liquid coatings is related to viscosity, working temperature/humidity, and application process (spray or dip), and can only be controlled to a tolerance of approximately +/- 50% of the final thickness.
Parylene thickness is a function of the amount of vaporized dimer and chamber dwell time and can be controlled accurately to within +/- 5% of targeted thickness for most typical applications.