Oblique angle initiated chemical vapor deposition for patterning film growth

Initiated chemical vapor deposition (iCVD) can be used to deposit thin polymer films on a variety of substrates. In this work, the monomer precursor was introduced at an oblique angle to the substrate using an inlet extension, and the pattern of the resulting polymer film was studied as a function of deposition time, substrate temperature, monomer flow rate, reactor pressure, and vapor flow angle. The polymerizations ofn-butyl acrylate, methacrylic acid, and 2-hydroxyethyl methacrylate were examined to determine the generality of the trends across several monomers. It was found that the monomer flow rate significantly affected the pattern of the deposited polymer by shifting the location of the thickest point in the films. Increasing the deposition time, decreasing the substrate temperature, and increasing the reactor pressure all increased the polymer deposition rate consistent with conventional iCVD; however, the pattern of the deposited polymer did not vary with these parameters. Computational analysis was used to determine how the inlet extension affects the pressure and velocity profiles within the reactor. The data demonstrate that the introduction of a monomer precursor at an oblique angle can be used to pattern polymer films during iCVD.