ZnO Thin Film-Based New Electroless Metal Deposition

Abstract

Electroless metal deposition plays an important role in the fabrication of printed circuit boards mainly due to its ability to produce uniform metal films on insulating substrates (e.g., ceramics, glass, polymers). However, the adhesion of the electrolessly deposited metal films, particularly coinage metals (Cu, Ag, Au) on ceramic substrates is usually poor, even on roughened substrates. Nevertherless, using our newly developed electroless metal deposition process, which is characterized by the use of a ZnO thin film as an intermediate layer between the substrate and the metal deposit, metal films with high adhesive strength can be achieved even on smooth glass substrates. In addition, this new process possesses the advantages of 1) simple processing procedures and 2) the ability to fabricate fine metal patterns in a fully additive fashion based on the photosensitivity of the ZnO films. New functions based on this process have been discovered in our recent research. In the present paper, the processing steps involved in this new method, the formation mechanism of catalytic Pd particles, the adhesion mechanism, as well as its possible applications in pattern fabrication, are briefly reviewed, based on our recent work.