We applied the femtosecond laser-assisted etching technique, that is, irradiation of focused femtosecond
laser pulses followed by selective chemical etching, to volume removal inside sapphire.
At room temperature, volume etching only slightly advanced while residue remained inside the
volume. By increasing the etching temperature, complete volume etching without residue was
achieved. Complete etching was, however, accompanied by undesirable phenomena of surface pits
or cracks, which are expected to be excluded through further improvement of processing.
AbstractReal 3-D sub-νm lithography was performed with two-photon polymerization (2PP) using inorganic-organic hybrid polymer (ORMOCER®) resins. The hybrid polymers were synthesized by hydrolysis/polycondensation reactions (modified sol-gel synthesis) which allows one to tailor their material properties towards the respective applications, i.e., dielectrics, optics or passivation. Due to their photosensitive organic functionalities, ORMOCER®s can be patterned by conventional photo-lithography as well as by femtosecond laser pulses at 780 nm. This results in polymerized (solid) structures where the non-polymerized parts can be removed by conventional developers.ORMOCER® structures as small as 200 nm or even below were generated by 2PP of the resins using femtosecond laser pulses. It is demonstrated that ORMOCER®s have the potential to be used in components or devices built up by nm-scale structures such as, e.g., photonic crystals. Aspects of the materials in conjunction to the applied technology are discussed.
Three-Dimensional Residue-Free Volume Removal inside Sapphire by High-Temperature Etching aftercmd="newline" Irradiation of Femtosecond Laser Pulses