LARGE-SCALE 2-STEP SELECTIVE ALUMINUM CVD ON LASER PATTERNED PALLADIUM LINES

In the present report we first outline and characterize the details of uniform deposition of PdAc from an acetone solution on a large area. Then, we investigate the parameters that highly influence the thickness and quality of the laser direct-written palladium lines (spin coating speed among others). Currently, good quality and uniform patterning of laser written thin lines of Pd have been achieved on samples as large as 4 inches in diameter. The Pd lines are well resolved (minimum of 3 mum in width now) and exhibit fairly good resistivity around 30 muOMEGA . cm. They also showed good adhesion to the SiO2 substrate as they endure repeated Scotch tape adhesion tests. Moreover, the second step of highly selective Al-CVD has been investigated under various conditions and gave rise to resistivities of about 6.5 muOMEGA . cm and 3000 angstrom thickness for a 7 min deposition. This process stands out as very promising for packaging and high density interconnect technologies.