High speed and low cost FOB (Film-on-Board) direct bonding using laser soldering technology

The laser soldering was estimated for a high productivity and cost-effective FOB (Film-on-Board) bonding method. The local solder joint is rapidly heated up in laser soldering. The process can be optimized by laser power, beam scanning speed, scanning path, solder pre-coating condition, flux, and soldering fixture. It was possible to get enough peel strength, process yields, and reliability on the optimized laser soldering process condition. The two major failure modes in laser soldering were cold solder joint and burning of film.