Excimer Laser Induced 5.8 eV Absorption and 1.9 eV Emission Bands in Fused Silicas

1991 ◽  
Vol 244 ◽  
Author(s):  
Nobu Kuzuu ◽  
Yasutaka Matsumoto ◽  
Masataka Murahara

ABSTRACTCharacteristics of ArF excimer laser induced 1.9 eV emission and 5.8 eV absorption bands in type III and soot remelted silicas were investigated. In a type III silica synthesized in a reducing condition, an absorption band at 5.8 eV band is induced. The creation of this band can be prevented by annealing in an atmosphere of He. In the soot remelted silicas with and without OH, the creation of the 5.8 eV band is strongly promoted by annealing in H2. An emission band at 1.9 eV is induced in a type III fused silica synthesized in an oxydizing condition and soot remelted silica containing OH. When annealing in He, creation of the 1.9 eV band is strongly promoted in the former but suppressed in the latter sample. This difference is derived from the difference of higher order structures between the type III and the soot remelted silicas.

1992 ◽  
Vol 45 (5) ◽  
pp. 2050-2054 ◽  
Author(s):  
Nobu Kuzuu ◽  
Yoshikazu Komatsu ◽  
Masataka Murahara

1992 ◽  
Vol 279 ◽  
Author(s):  
Yasutaka Matsumoto ◽  
Yoshihiro Yoshikado ◽  
Masataka Murahara

ABSTRACTFused silica is widely used material in window and lens applications for excimer laser processing. The transmittance of the laser beam in fused silica is attenuated approximately 40% by high fluence ArF excimer laser irradiation. The attenuation of the transmittance corresponds to the growth of an absorption band at 215nm. This phenomenon is troublesome for laser lithography. To investigate this effect, we examined the laser induced luminescence and absorption under various conditions. The 215nm absorption band was diminished by annealing at 900 °C for 2 hours in He ambient. Ke could successfully obtain good optical material, whose transmittance remains constant with increasing ArF laser(193nm) shot exposure.


1998 ◽  
Vol 11 (3) ◽  
pp. 489-492
Author(s):  
Takeshi Okino ◽  
Koji Asakawa ◽  
Naomi Shida ◽  
Tohru Ushirogouchi

1995 ◽  
Author(s):  
Makoto Nakase ◽  
Takuya Naito ◽  
Koji Asakawa ◽  
Akinori Hongu ◽  
Naomi Shida ◽  
...  

1967 ◽  
Vol 40 (2) ◽  
pp. 663-672
Author(s):  
Rempei Gotoh ◽  
Tohru Takenaka ◽  
Naomi Hayama

Abstract A method for simultaneous measurements of stress and infrared dichroism as time-dependent behavior of polymer films was devised using a double beam infrared spectrometer. The film sample held between clamps of a stretching device was placed just in front of the entrance slit of the spectrometer where the sample and reference beams came alternately. Two polarizers were used, one in the sample beam and the other in the reference beam. Thus the sample and reference beams were polarized to have the electric vectors parallel and perpendicular to the stretching direction of the sample, respectively. With this arrangement the spectrometer responded only to the difference in the transmittance of the two beams. Setting the spectrometer at one of the wavenumbers of the absorption band maxima, we could record continuously the change in its dichroism during mechanical treatments which gave rise to molecular orientation in the sample. The stress was recorded automatically by means of a pair of strain gauges pasted on the cantilever beam of the stretching device. By theoretical considerations, a simple relationship was found to exist between the quantity recorded on the spectrometer by this method and the orientation function of transition moment of a vibrational absorption band with respect to the stretching direction. The method was applied to the stress relaxation experiments of vulcanized natural rubber carried out at different elongations less than 600 per cent and at room temperature. Changes of infrared dichroism were measured for five absorption bands at 1664, 1380, 1361, 1129, and 844 cm−1, of which the last one is a crystalline band. From the results of this study, the stress relaxation observed was ascribed mainly to the amorphous orientation rather than to the crystalline orientation, which was completed almost immediately after elongation.


2013 ◽  
Vol 552 ◽  
pp. 252-255
Author(s):  
Yan He Chang ◽  
Chun Shui Jin ◽  
Chun Li ◽  
Jing Cheng Jin

ArF excimer laser is the main light resource for the microlithography technology. In the laser cavity, the optical components with lowest absorption and scattering loss are necessary. As a consequence only a few materials are promising candidates for 193nm coatings with high transmittance or high reflectance. Fluoride films exhibit relatively low optical loss as well as high laser induced damage thresholds. The potentiality of LaF3 and MgF2 is evaluated in respect of the production of improved optical coatings for applications. For this purpose, single layer is prepared by thermal evaporation at the deposited temperatures of 523K on Fused Silica. A first order bulk inhomogeneity model for extracting the optical constants of weak absorbing film is applied, which is based on spectrophotometry. Refractive index (n) and extinction coefficient (k) of the optimal LaF3 film are 1.678 and 2.24×10-3 at 193nm. In the case of the optimal MgF2 film, n and k are 1.443 and 4.72×10-4 at 193nm. High reflection (HR) LaF3/MgF2 coatings are designed and fabricated for normal incident on CaF2. The experimental results indicate that after coated and fluoride coatings deposit, according to optimal process, can have more suitable optical properties at deep ultraviolet (DUV), the reflectance of HR coatings reaches more than 98% at 193nm.


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