| abstract |
The present invention relates generally to a new process of cleaning of objects that relate to semiconductor fabrication processes, such as, for example, conductive paste screening in the production of multilayer ceramic substrates and composite solder paste by stencil printing in electronic circuit assembly. Specifically, this invention is concerned with removing a metal/polymer composite paste from screening masks and associated paste making and processing equipment used in printing conductive metal pattern onto ceramic green sheet in the fabrication of semiconductor packaging substrates. This invention is also concerned with cleaning of solder paste residue from stencil printing equipment used in electronic module assembly surface mount technology for SMT discretes, solder column attachment, and BGA (Ball Grid Array) attachment on ceramic chip carrier or for screening solder paste onto printed circuit board. More particularly, this invention is concerned with cleaning of paste residue from metal, ceramic, and plastic substrates by a non-alkaline semi-aqueous cleaning method employing high boiling propylene glycol alkyl ether or mixtures of propylene glycol alkyl ether and propylene glycol solvents. |