An Anti-reflection Film Required for the Mask in Deep Ultraviolet Region by Electron Gun

• Main Authors: WANG,CHI-CHIEH, 王繼傑
• Other Authors: LEE,WEI-YU
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/btn6b9

碩士 === 中華科技大學 === 機電光工程研究所碩士班 === 106 === Nowadays, with the increasing demand for optical resolution in technology, the usage of short and very short wavelength lasers becomes indispensable. However, the usage of short-wavelength lasers (or deep ultraviolet) brings with it new problematics: In the visible light wavelength range, regardless whether it is a single layer or multilayer films, the visible light almost cannot damage the films; but, in the case of deep ultraviolet, defects, structures, absorption and surface roughness causes, often, irreversible damage to the thin film because of the high concentration of energy. Ion beam sputter deposition(IBSD) has been used in the past for producing optical thin films, which can grow dense and few defect layers. However, because of this tight accumulation, the laser energy cannot be conducted quickly. Compared to ion beam sputter method, the thermal evaporation method can reduce the damage, because the low density leads to make Laser in having enough time to conductive and obtain buffer. In addition, Considering increase the refractive index and reduce the surface roughness of the film, this experiment used IAD once to generate plasma at 250 °C with oxygen, but this method will result up to four decimal k value in the visible light region. The method should be given up if we need to manufacture extreme low absorption films. In this research, we focus on 248nm wavelengh, fabricate Al2O3 to has 4.861×10^(-4) k value at 225nm, MgF2 has 3.781×10^(-4) k value at 211nm, and it’s own surface roughness (Rq) is 0.846 nm and 0.738 nm. Use Al2O3 and MgF2 deposition on quartz substrate, two layers thin films make anti-reflection lens which achieve a reflectance of 0.5% or less.