| Project/Area Number |
15560016
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thin film/Surface and interfacial physical properties
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
HATANO Tadashi TOHOKU UNIVERSITY, INSTITUTE OF MULTIDISCIPLINARY RESEARCH FOR ADVANCED MATERIALS, RESEARCH ASSOCIATE, 多元物質科学研究所, 助手 (90302223)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2004: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2003: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | multilaver / thickness distribution control / speed programmable shutter / ion beam sputtering / ion gun / concave mirror / normal incidence spectral reflectance / 膜厚制御 |
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| Research Abstract |
In ion beam sputtering deposition, the temporal stability of ion guns is a dominant factor for the accuracy of thickness control. Mo/Si multilayer concave mirrors for use at 13.5 rim need a reflectance peak wavelength within an error of 2%, while it has been 10% owing to the variation of the sputtering rate of our deposition apparatus. Therefore a stable run of ion guns to decrease the sputtering rate variation under 2% has been significant. Main parameters of an ion gun are Ar flow rate, accelerator voltage and extractor voltage. Ion beam output dependence on these factors has been investigated in detail. The condition for maximum ion beam output was found to be 1.4 sccm Ar flow rate, -1.4 kV accelerator voltage and +300 V extractor voltage. Then the temporal stability dependence on the Ar flow rate was investigated. The ion beam output was found to become more stable at a lower level when the Ar flow rate increases. The optimum Ar flow rate lies in the range between 1.7 and 2.0 sccm as a conclusion. Furthermore the ion beam output was monitored in the total ion flow and in the ion density by electrodes at the extractor and at the beam shutter, respectively. Strong correlations between the room temperature and the ion flow and between the source voltage and the ion flow were found, which implies how to improve the stability.
In our original technique of the programmable shutter for thickness distribution control, the calculation method of the minimum elapsed time was newly derived and the shutter shape to extend the mechanical stroke was reexamined. Mo/Si multilayer concave mirrors of radii of curvature of 50, 270 and 300 mm were fabricated and their thickness distributions were evaluated by normal incidence soft X-ray reflectometry at the Photon Factory, KEK.
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