This Letter describes an all-solid-state continuous-wave, deep-ultraviolet coherent source that generates more than 100 mW of output power at 193.4 nm. The source is based on nonlinear frequency conversion of three single-frequency infrared fiber laser master-oscillator power-amplifier (MOPA) light sources.

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We present a source of line-narrowed continuous-wave (CW) radiation at 193.4 nm with over 10 mW of output power for the first time, to our knowledge. The system configures four successive frequency conversions of outputs from three single-frequency fiber amplifiers at 1064, 1107, and 1963 nm. The 266-nm beam produced by frequency quadrupling of 1064-nm light is sum-frequency mixed with the 1963-nm light to generate 234.3-nm radiation, which is consequently mixed with the 1107-nm light to generate 193.4-nm radiation. Both mixings are achieved in temperature-tuned non-critically phase-matched (NCPM) crystals.

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Proximity effect correction for electron beam (EB) direct writing is studied in this paper. An iterative calculation of exposure-dose modulation by equalizing the deposited energy of all figures requires an extremely long calculation time, especially in the case of high EB acceleration voltage. Therefore it is not practical for the correction of LSI. The correction method using pattern-area density, however, could realize the high-speed proximity effect correction. In this paper, this method is first investigated from the standpoint of the correction accuracy. Next, the applicability of this method to two critical cases is examined. One is the patterning on a heavy-metal substrate, on which backscattering yield of electrons is high. The other is the application to the cell-projection exposure, in which it is impossible to modulate exposure dose inside the cell. Lastly, the calculation time of the proximity effect correction is evaluated for 64 Mbit dynamic random access memories (MbDRAMs).