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

Volume

25

Issue

4

fYear

2002

fDate

10/1/2002 12:00:00 AM

Firstpage

253

Lastpage

256

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;

fLanguage

English

Journal_Title

Electronics Packaging Manufacturing, IEEE Transactions on

Publisher

ieee

ISSN

1521-334X

Type

jour

DOI

10.1109/TEPM.2002.807724

Filename

1176906