Fabrication of fine copper lines on AZ 5214 (TM) patterned silicon substrates by selective chemical vapor deposition

Copper features with dimensions down to 0.5 mum were fabricated on silicon substrates by selective chemical vapor deposition, For the fabrication oxid ized (100) silicon substrates were used, covered with a film grown by LPCVD at 0.1 Torr and 550 degreesC, from W(CO)(6) decomposition. These substrate s were subsequently covered with AZ 5214 (TM) photosensitive polymer, which has been developed as both positive and negative tone resist. Copper was t hen chemically vapor deposited on the patterned substrates by 1, 5-cyclooct adiene Cu(I) hexafluoroacetylacetonate decomposition, at 1 Torr and tempera tures of 110 and 140 degreesC. A vertical, cold-wall reactor was used, equi pped with a UV lamp permitting photon-assisted deposition. Under UV illumin ation, copper was deposited on resist covered and uncovered parts of the su bstrate. In absence of illumination, the metal was selectively grown on the tungsten film only at relatively slow rates (1 and 3.5 nm/min at 110 and 1 40 degreesC respectively). Copper films had a granular form with a gain siz e increasing with temperature (150 and 550 nm at 110 and 140 degreesC respe ctively). After depositions the resist was removed in oxygen plasma leading to the formation of fine copper features.