Physical properties of an oxide photoresist film for submicron pattern lithography

• Published in: Thin solid films Vol. 542; pp. 409 - 414
• Main Authors: Chiang, Donyau, Chang, Chun-Ming, Chen, Shi-Wei, Yang, Chin-Tien, Hsueh, Wen-Jeng
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 02.09.2013; Elsevier
• Subjects: Coefficients; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Crystallization activation energy; Deposition; Deposition by sputtering; Dielectric thin films; Dielectric, piezoelectric, ferroelectric and antiferroelectric materials; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Direct laser writing; Etching; Exact sciences and technology; Extinction coefficient; Flow rate; Fundamental areas of phenomenology (including applications); Lasers; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optics; Oxide photoresist; Oxides; Photoresists; Physics; Pits; Refraction index; Semiconductor lasers; laser diodes; Sputtering; Thermal lithography; Oxide photoresist; Extinction coefficient; Refraction index; Thermal lithography; Crystallization activation energy; Sputtering; Direct laser writing; Refractive index; Aperture; Laser diodes; Deposition process; Thin films; Cathode sputtering; Semiconductor lasers; Temperature effects; Etch pits; Physical vapor deposition; Apertures; Absorption spectra; Activation energy; Optical absorption; Crystal structure; Temperature dependence; Dielectric materials; Lithography; Crystallization; X-ray diffractometers; Laser beams; Transmittance; Physical properties; Heat treatments; Laser writing; Dielectric thin films; Photoresists; Reactive sputtering; Sputter deposition
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2013.05.134

The minimum etched pits of 300nm diameter and the trenches of 300nm width with a 50nm depth for both geometries are prepared in the GeSbSn oxide photoresist on the silicon substrates. The lithographic patterns are recorded by direct laser writing, using a 405nm laser diode and 0.9 numerical aperture media disc mastering system. The developed pit diameters in an inorganic oxide photoresist are smaller than the exposed laser beam spot diameter due to thermal lithography. The crystal structures of the as-sputtered and the annealed powder samples scraped from the sputtered films are examined by X-ray diffractometer. The effect of the heating rate on the crystallization temperatures is evaluated by a differential scanning calorimeter and the crystallization activation energy is determined from Kissinger's plot. The optical and absorption characteristics of the oxides are strongly dependent on the oxygen flow rate during the reactive magnetron sputtering process. The transmittance of the deposited films increases and the absorption decreases with increasing oxygen flow rate, which implies that at high oxygen flow rate, the film resembles dielectric material. The oxygen flow rate during the deposition process is defined within a limited range to obtain the proper extinction coefficient. The working extinction coefficients of the films ranging from 0.5 to 0.8 are applied in this study to achieve the sharp and vertical edge of the etched pits and trenches of 50nm depth. •A photoresist layer consisting GeSbSnO with submicron patterning for optical device applications.•The thermal, optical properties and crystallization behaviors are reported.•A better working extinction coefficient ranges are decided experimentally.•The ranges define minimum size of the etched marks with smooth boundary.•Thermal lithography concept is introduced to explain experimental results.