Title :
A new bumping process using lead-free solder paste
Author :
Suga, Tadatomo ; Saito, Keisuke
Author_Institution :
Res. Center for Adv. Sci. & Technol., Univ. of Tokyo, Japan
fDate :
10/1/2002 12:00:00 AM
Abstract :
In this paper, we report development of a new process for lead-free solder bumping with no flux residues, using stencil printing and hydrogen radicals, which can lessen both the environmental load and the manufacturing cost of solder bumping. In this process the reduction of the hydrogen radicals, instead of the flux, will eliminate the surface oxides of the stencil printed lead-free solder paste. Sn-3.0Ag-0.5Cu lead-free solder paste, which contains no residue flux was printed on an 8-in wafer. Hydrogen plasma was radiated for a minute during the reflow process, and the printed paste formed a bump. Reflow experiments without hydrogen radicals treatment were also carried out for comparison, where no successful reflow could be observed.
Keywords :
copper alloys; fine-pitch technology; hydrogen; microassembling; packaging; reflow soldering; silver alloys; surface mount technology; tin alloys; H; H plasma radiation; H radicals treatment; Pb-free solder bumping process; SMT; Sn-3.0Ag-0.5Cu lead-free solder paste; SnAgCu; flux residue free process; hydrogen radicals; manufacturing cost; reflow process; stencil printing; Cleaning; Costs; Environmentally friendly manufacturing techniques; Hydrogen; Lead; Plasma applications; Plasma materials processing; Plasma waves; Printing; Surface treatment;
Journal_Title :
Electronics Packaging Manufacturing, IEEE Transactions on
DOI :
10.1109/TEPM.2002.807724
