Polymerization of para‐xylylene derivatives (parylene polymerization). I. Deposition kinetics for parylene N and parylene C

Abstract

Kinetic aspects of parylene N [unsubstituted poly(para‐xylylene)] and Parylene C [monochlorosubstituted poly(para‐xylylene)] were studied. The conversion of starting material (dimer of either p‐xylylene or chloro‐para‐xylylene) to polymer is quantitative (ca. 100%). Consequently, the total polymer formed in a closed system is directly proportional to the amount of dimer charged. However, the percentage of the total amount of polymer formed which deposits on substrate surfaces, placed in the deposition chamber, as well as the polymer film growth rate are dependent on operational factors such as the temperature of the substrate, sublimation of dimer temperature, flow pattern of the reactive species, etc. Parylene C, being a heavier and more polar molecule, has the tendency to deposit easily in the deposition chamber compared to the deposition of Parylene N. Parylene C also has a higher ceiling temperature for deposition than Parylene N. This situation has been investigated from the viewpoint of excess thermal energy which hinders polymer formation (deposition) due to the exceedingly high entropy change necessary for polymer deposition to occur. The addition of a cool (i.e., room temperature) inert gas was shown to increase the deposition of Parylene N on substrate surfaces placed in the deposition chamber. The deposition increase and acceleration of deposition (film growth) rate were found to be related to the size and molecular weight of the inert gas pressure maintained in the system. The accelerating effect is explained by the increase in third‐body collisions to dissipate the excess thermal energy of the reactive species.

Growth of sculptured polymer submicronwire assemblies by vapor deposition

“…Unlike conventional PVD systems such as thermal evaporators or sputtering systems [14], deposition variables such as pressure or deposition rate are indirectly adjusted by varying the vaporizing and pyrolizing temperatures. The type C parylene, which was deposited is the polymer form of the low-molecular-weight dimer of para-chloro-xylylene [15]. Polymeric parylene is formed by evaporating a dimer and then pyrolizing the dimer into a monomer precursor for polymer formation.…”

Plasma removal of Parylene C

“…The thickness of deposited Parylene is a function of substrate temperature [32,33] so biased resistors were used to generate a localized heat gradient that prevented deposition in regions held above 70…”

Flexible organic field-effect transistors fabricated by the electrode-peeling transfer with an assist of self-assembled monolayer

“…The pattering process employed here especially for the gate electrode should be improved to be replaced by other methods, for example, photolithography or microcontact printing. [8][9][10][11][12] It may also be possible to employ conductive polymers patterned with ink-jet printing technology for the gate electrode, for which a high conductivity is not required. The remaining problem to be considered in this method is how the capacitance of the insulator layer increases.…”