Surface Photochemically Activated Chemical Vapor Deposition of Patterned Aluminum Thin Films

KrF excimer laser (248 nm) images of mask patterns have been used to photochemically activate the surface catalytic decomposition of triisobutylaluminum (TIBA). The activation step is shown to involve the photolysis of organoaluminum surface adlayers leading to the formation of reactive Al sites. These sites serve to selectively nucleate the thermal decomposition of TIBA which results in the growth of high quality Al films (resistivities ~5 µΩ-cm). The growth on the chemically inert surfaces of SiO2 and Al2O3 is extremely selective and results in patterns with resolutions ~2 µm. To evaluate the utility of this process for real circuit applications, the laser activated deposition technique has been used in conjunction with standard photolithographic processing to fabricate metal-oxide field effect transistors and Al interconnects. The successful fabrication of working devices indicates that the laser activated deposition technique is compatible with standard photolithographic patterning schemes and may provide a means for simplifying integrated circuit fabrication.