| 摘要 |
Sputtering targets with a working portion consisting of aluminium or a very pure-base aluminium alloy are disclosed. The targets are selected according to a suitable method, comprise no more than 0.1 internal splits larger than 0.1 mm per cm<3> of working target metal, and are particularly suitable for applications requiring very fine etching. An ultrasonic internal health testing method for producing such targets is also disclosed. In particular, the method comprises selecting an ultrasonic sensor operating at a working frequency higher than 5 MHz and preferably of 10-50 MHz, adjusting the appropriate measurement chain, then counting by size and number the internal splits per unit volume in a target that is immersed in a liquid and has a number of artificial flaws simulating splits in the target, and selecting the targets that have a split density of no more than 0.1 splits larger than 0.1 mm per cm<3> of working target metal, and preferably of fewer than 0.1 splits larger than 0.04 mm per cm<3> of working metal. Furthermore, sputtering target precursors containing fewer than 0.1 splits larger than 0.04 mm per cm<3> are disclosed. |
