Shungo Sugawara

Low-loss passive polymer optical waveguides with high environmental stability

Deuterated polysiloxane with high transparency and high thermal stability was newly synthesized for use as optical waveguide material. Single-mode channel waveguides using the polymer were fabricated by conventional photolithography and dry etching. The propagation loss of the channel waveguides was measured and found to be 0.17 dB/cm at 1.31 /spl mu/m and 0.43 dB/cm at 1.55 /spl mu/m. The thermal and environmental stability of the waveguides was demonstrated by the fact that the propagation loss remained unchanged after tests at 200/spl deg/C for 30 min, at 120/spl deg/C for 1000 h, and at 75/spl deg/C and 90% RH for 1000 h.

Chloromethylated Polystyrene as Deep UV and X-Ray Resist

The deep uv and X-ray lithographic characteristics of high-performance negative electron resist chloromethylated polystyrene (CMS) were investigated. The sensitivity and resolution of a series of CMSs synthesized from nearly monodispersed polystyrene were evaluated as functions of molecular parameters. In CMS with a molecular weight of 1.8×105 showing a resolution better than 1.5 µm, a high sensitivity of 29 mJ/cm2 to X-rays and a sensitivity to deep uv about 40 times higher than that of PMMA was achieved. This high sensitivity is attributed to the high reactivity of the chloromethyl group, as verified by the high G value of CMS (5.4), 50 times larger than that of polystyrene. In contrast to most negative resists, where oxygen in air depresses the sensitivity, the sensitivity of CMS is hardly affected by the atmosphere. The sensitivity and resolution in the deep uv system are particularly affected by light absorption, because CMS exhibits strong absorption between 200 to 300 nm.