Using Ultraviolet (UV) Laser Radiation to Coat a Micron-scale Thin Film onto a Mask for Micro-transparent Defect Repair
M. Wang, F.R. Liu, C. Huang and J.M. Chen
The photo-mask is a basic tool in lithography process which has a crucial role in the development of modern integrated circuits. This paper describes a new method. The method is that 355 nm ultraviolet (UV) laser through the Cr-mask directly affects nano-chromium powder between Crmask and the substrate to coat a layer of film on the mask. The morphology of the film was observed under the optical microscope, surface profiler and a scanning electron microscope (SEM). The roughness of the centre area of the film is about 108 nm and the average thickness of the film is about 308 nm determined by laser confocal microscope system. Also the elemental composition of the film contains Cr determined by energy dispersive spectroscopy (EDS). The adhesion of the film was good tested by tape, acid, alkali and organic solvents. The mechanism of coating thin film was also discussed. The result is that the morphology, thickness, roughness and adhesion of the film are good and the film is obtained through the process of amorphous change. Finally the conclusion is that this method can be used to the repair of Cr-mask micro transparent defects.
Keywords: Ultraviolet (UV) laser, photo-mask, nano powder, thin film, transparent, defect, repair