Stress reduction of chromium thin films deposited by cluster-type sputtering system for ultra-large-size (550 x 650 mm) substrates

In order to reduce the intrinsic tensile stress in sputtered Cr films, the relationship between sputtering condition and the stress properties was inv estigated By using a laboratory-scale planar de magnetron sputtering appara tus, it was shown that the tensile stress in the films were decreased with increasing substrate temperature, increasing de power and decreasing gas pr essure. However, it was still as high as 1000 MPa, even when the optimized process condition was applied to a cluster-type sputtering apparatus for ul tra-large-size (550 x 650 mm) substrates. By changing the sputtering gas fr om Ar to Ne with the cluster-type apparatus, the stress was considerably de creased to the value of approximately 100 MPa. Stress reduction mechanism w as discussed in the light of atomic peening effects; the energy of the impi nging species at the substrate surface is enhanced in the case of Ne. (C) 1 998 Elsevier Science Ltd. AII lights reserved.