Cathode sputtering targets with a low level of particle emission, precursors of these targets, and processes for obtaining them
US5887481A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 9, 1996 |
| Grant date | Mar 30, 1999 |
| Priority date | — |
| Expiry date | Dec 9, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/2697
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A process is provided for ultrasonic testing the internal soundness of cathode sputtering targets including an active part made of very pure aluminum or of very pure aluminum alloy. In particular, this process, after the choice of an ultrasound sensor functioning at an operating frequency greater than 5 MHZ, and preferably between 10 and 50 MHZ, and adjustment of the appropriate measurement sequence, using a target immersed in a liquid and having certain artificial defects simulating the decohesions in the target, consists of taking a count in terms of size and number of the internal decohesions per unit volume and of selecting the targets with a decohesion density of .ltoreq.0.1 decohesion larger than 0.1 mm per cm.sup.3 of active metal of the targets, and preferably less than 0.1 decohesion larger than 0.04 mm per cm.sup.3 of active metal. The process also pertains to selecting precursors of the cathode sputtering targets, containing less than 0.1 internal decohesion larger than 0.04 mm per cm.sup.3.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.