A Breakthrough in Sputtering Target Inspections: Ultra-High Speed Phased Array Scanning with Volume Focusing

In the manufacturing industry, more and more plate parts are inspected to detect tiny defects. As the rate of manufacturing increases, new and innovative inspection methods are required. This paper presents the method and results for inspecting sputtering targets, which are typically used in LCD manufacturing. The flaws are either inclusions or disbonds, in the range of 0.5mm in diameter, or thin slits in the range of 5μm by 5mm long. Over the years, the technique progressed from using single element probes with high speed mechanical scanners to conventional phased array with electronic scanning. This improvement resulted in productivity increases by a factor of more than 4. However, Volume Focusing offers a new breakthrough in phased array technology, exceeding conventional phased array scanning speeds by a factor of 4.