下地層ならびに超高真空中加熱プロセスによるCu薄膜の面内結晶粒径の増大と表面平坦化 Lateral Grain Size Enlargement and Surface Flattening of Cu Thin Films by using Adequate Underlayers and by Thermal Annealing in Ultra High Vacuum
The effects of body centered cubic (BCC) solid solution underlayers on the metallurgical size and flatness of Cu thin films, fabricated on them, were investigated. As the underlayer materials, Cr<SUB>80</SUB>Al<SUB>20</SUB>, Cr<SUB>90</SUB>Ni<SUB>10</SUB>, Cr<SUB>80</SUB>Fe<SUB>20</SUB>, Fe<SUB>75</SUB>Cr<SUB>25</SUB> and Fe were examined. Lateral grain size of the Cu films fabricated on the Cr-Al, Cr-Ni, Cr-Fe, Fe-Cr under layer was enlarged, comparing to that on the Fe underlayer. The difference between the surface energy (γ<SUP>X</SUP><SUB>S</SUB>) and the interfacial energy (γ<SUP>X-Cu-</SUP><SUB>SL</SUB>) of these underlayer is close to the surface energy of Cu at the melting point (γ<SUP>Cu</SUP><SUB>S</SUB> (<I>T</I><SUB>m</SUB>)). However, the surface roughness of Cu films simultaneously increased with increasing the lateral grain size. In order to suppress the surface roughening of Cu films, post-thermal annealing procedure was applied under the ultra-high vacuum for the films fabricated on the Cr-Ni and Cr-Ni-Fe underlayers. We finally succeeded to enlarge the lateral grain diameter more than 100 nm for 50-nm-thick Cu films, maintaining a flat surface (<I>R</I><SUB>a</SUB> = 0.32 nm).
- 真空 = JOURNAL OF THE VACUUM SOCIETY OF JAPAN
真空 = JOURNAL OF THE VACUUM SOCIETY OF JAPAN 47(3), 124-127, 2004-03-20
The Vacuum Society of Japan