Plasma polymer films for 532 nm laser micromachining

M. S. Silverstein, I. Visoly, O. Kesler, M. Janai, Y. Cassuto

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Laser micromachining with a frequency doubled Nd: YAG laser (532 nm) can replace more complex microlithographic processes for rapid turnaround in the development of prototype application-specific integrated circuits. Plasma polymerization is a rapid, dry, environmentally friendly process that yields crosslinked pinhole-free films. Plasma polymerized films of ethylene and an additional gas [PP(gas/E)] were investigated for their micromachining potential. The deposition rates, molecular structures, physical properties and optical properties of the polymers were characterized. PP(Ar/E), with relatively little oxygen and no nitrogen, with superior substrate adhesion and with no debris generated on laser micromachining was chosen as the optimal laser micromachining film. The PP(Ar/E) coefficient of optical absorption at 532 nm (α532), related to unsaturated group concentration, increased with the ratio of plasma power to ethylene mass flow rate [W/Fm(E)]. α532 reached an asymptote of 2.9 μm-1 at high W/Fm(E) and could be enhanced slightly using postpolymerization ultraviolet exposure. The optimum conditions were using Ar/E=1/1 and 75 W to produce a 0.6 μm thick film for micromachining at 2 J/cm2 focused 0.25 μm beneath the surface. The laser pulse in a 1.2 μm thick film was not fully developed at 2 J/cm2 and exhibited rounded corners at 4 J/cm2, indicating that multiple low energy pulses would be preferable. A complicated and densely packed pattern with several different pulse sizes in which neighboring holes from pulses in close proximity do not merge was accurately reproduced in PP(Ar/E) using laser micromachining.

Original languageEnglish
Pages (from-to)2957-2967
Number of pages11
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Volume16
Issue number6
DOIs
StatePublished - 1 Jan 1998
Externally publishedYes

Fingerprint

Dive into the research topics of 'Plasma polymer films for 532 nm laser micromachining'. Together they form a unique fingerprint.

Cite this