ULTRASONIC NON-DESTRUCTIVE TESTING OF CERAMIC SPUTTERING TARGETS

Detection of defects during manufacturing of ceramic sputtering targets is important in order to prevent problems in the sputtering process and to produce high quality thin films, as required by the industry. This is especially important for large size targets with planar and, moreover, rotary configurations. Defects in bare ceramic components, such as forming flaws, cracks, and voids, and in bonded sputtering targets, such as de-bonds between the ceramic and metallic backing, have to be eliminated. Ultrasound C-scan systems were utilized for non-destructive inspection of indium tin oxide (ITO) ceramic sputtering targets. The testing was conducted for planar and rotary ITO ceramic components with densities up to 99.5% of TD and for actual bonded targets. Instruments with various designs were used for the testing, including systems, which were capable of inspecting long rotary targets with a total length up to 3 m or more. Transducers with frequencies of 10-30 MHz were used for ultrasonic evaluation. Microscopy studies and dye penetration testing of ceramic components were also used to confirm the presence of defects found by ultrasound C-scanning, and to understand their origin. Non-destructive ultrasonic evaluation can be successfully used as a quality control in the manufacturing of ceramic sputtering targets.