Abstract

Defect densities in coatings deposited by planar magnetron sputtering were measured with a Tencor Surfscan 6200 laser particle detector. The measurements were performed on two sets of coatings - one deposited in a research chamber at the Center for X-ray Optics (CXRO) at Lawrence Berkeley Laboratories, the other deposited in a MTI Sypherline used for metal deposition in a class 1 cleanroom at the Microelectronics Development Laboratory (MDL) at Sandia National Laboratories.

For coatings deposited in the research chamber, as much as 90% of the defects counted were particulates deposited during venting of the chamber. As a result, these defects were located on the surface of the coatings and were removable by ultrasonic clean in de-ionized water. Of the remaining defects on these coatings, as much as 75% of them were generated from inside the chamber during the coating process. The average number of defects in 30 bilayers of Mo/Si was 20 cm^-2 for defects of sizes ≥ 0.5 µm latex-sphere-equivalent (LSE) diameter.

For coatings deposited in a clean chamber located in a class 1 cleanroom, the density of ≥ 0.5 µm LSE diameter defects in a 1000 Å thick Si film was 0.2 cm^-2. This is two orders of magnitude fewer defects compared with coatings deposited in a research chamber. For ≥ 0.14 µm LSE diameter defects, defect density was 7 cm^-2. Defect density also increased with increased film thickness.

© 1994 Optical Society of America