In this report an ultrathin Au nanoparticle (AuNP) film composed of photosensitive diazoresin (DR) and mercaptophenol (MP) capped AuNPs (MP-AuNPs) was fabricated by self-assembly (SA). The DR/MP-AuNP film was than patterned through a photomask by selective exposure to UV light and instantly developed in sodium dodecyl sulfate (SDS) aqueous solution. After sintering at 550 degreesC to remove the organic components, the DR-MP-AuNPs formed AuNPs. Taking advantage of the catalytic susceptibility of AuNPs toward electroless deposition of Cu, a Cu film micropattern with fine resolution (ca. 2-3 mum) and considerable thickness (ca. 130 nm) was prepared.