Title :
Fabrication of micro-optical structures by applying negative tone hybrid glass materials and greyscale lithography
Author :
Kärkkäinen, A. H O ; Rantala, J.T. ; Descour, M.R.
Author_Institution :
VTT Electron., Oulu, Finland
fDate :
1/3/2002 12:00:00 AM
Abstract :
Direct lithographic patterning of lenslet arrays with lens sags up to 75 μm and opto-mechanical structures with thickness up to 118 μm is demonstrated. using negative tone hybrid glass materials and greyscale and binary photomasks. The hybrid glass material features a maximum extinction coefficient of 2.0 × 10-4 μm-1 between 450 and 1600 nm, a refractive index of 1.531 at 632.8 nm and an estimated Abbe number of 45. The patterned structures exhibit rms surface roughness between 10 to 45 nm
Keywords :
masks; micro-optics; microlenses; optical fabrication; optical glass; photolithography; refractive index; surface topography; 10 to 45 nm; 118 micron; 450 to 1600 nm; 632.8 nm; 75 micron; binary photomasks; direct lithographic patterning; estimated Abbe number; greyscale lithography; lens sags; lenslet arrays; maximum extinction coefficient; micro-optical structure fabrication; negative tone hybrid glass materials; opto-mechanical structures; patterned structures; refractive index; rms surface roughness; thickness;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:20020032
