- Practical Use of Lead-Free Tin-Zinc-Aluminum (Sn-Zn-Al) Solder - - - - - Abstract Fujitsu has implemented a company-wide effort to progressively reduce the use of lead and eventually eliminate this environmental pollutant from its products. As part of this effort, it has developed a new lead-free solder that consists of tin, zinc, and aluminum and yet offers superior productivity and joint reliability. The new lead-free solder has a melting point equivalent to that of a tin-lead eutectic solder, and enables devices to be packaged at a lower temperature than with the increasingly popular tin-silver-copper solder. The new lead-free solder ensures highly reliable soldering both for existing component pins that contain lead, as well as lead-free component pins which will be widely used in the future. Thus, the new lead-free solder accelerates the elimination of lead from products. Fujitsu has already used PC boards containing the new lead-free solder in some products, and plans to extend its use to other products. This paper describes the characteristics of the new leadfree solder and the results of a study on its practical use. 154 FUJITSU.54, 2, p.154-160 (03,2003)
- - Pb 2004 3 EU RHS Restriction of Hazardous Substances in Electrical and Electronic Equipment 2006 7 Sn - Ag - Cu -1 (1) 199 - Zn - Al Sn-Zn-Bi Sn-Zn Al Sn-Zn-Bi Sn-Zn 200 Zn Bi Cu Zn Sn-Zn Cu Cu Cu Cu Sn-Zn-Bi Sn-8Zn-3Bi wt Cu 30 80 300 20 Cu Au Cu Au Ni -Zn Cu-Zn SMD Surface Mount Device 2 Sn-10Pb wt Cu LQFP Low Profile Quad Flat Package 208 pincu 2 100 mm 1.5 mm 150 100 Sn-8Zn-3Bi wt 10 N/ 150-1 - Sn-Zn - Sn-Ag - Sn-Pb 199 218 183 - EU FUJITSU.54, 2, (03,2003) 155
- - 100 (2) Bi Sn-Zn Pb Pd Sn-Zn-Bi EPMA Electron Probe Micro Analyzer Cu 6 m Cu-Zn Bi Pb Cu-Zn 8 m Pb Bi -1 Cu2 m Cu-Zn Bi Pb BiSn-Zn-Bi Sn-Pb Cu Pb Bi Sn 99.5 Sn- Pb-Bi Sn-Pb-Bi -2 Al Zn Pb Bi Sn-Zn Cu Bi Sn-Zn Zn Bi Al Sn-Zn a Cu b -1 Sn-Zn-Bi Fig.1-Rupture side at junction by Sn-Zn-Bi solder after high temperature leaving. Sn-Pb-Bi 三元共晶層 高温放置後に界面はく離が発生する層 Sn-Pbはんだめっきリード Pb Bi Zn Cuめっき基板パッド部分 Pb の接合界面への移動 Cu-Zn 金属間化合物層 -2 Sn-Zn-BiCu Fig.2-Mechanism of occurrence of interfacial separation between Sn-Zn-Bi solder and Copper pad. 156 FUJITSU.54, 2, (03,2003)
- - Zn Al Zn Zn Zn Zn Al Al Al Al-2 ZnAl Zn Al Al Al ZnAl Al Zn Zn Al Zn Zn-8Al wt 200 1 - Zn Al Al Al Zn Al Zn Al Zn Sn-Zn-Al EPMA 10 1 1/10 nm Al Al Sn-Zn-Al Sn-Zn Al Al Al 40 m Sn-Zn- Al Al AES Auger Electron Spectroscopy -3 Al Sn-Zn Al AES Al 60 ppm 1/4 AlAl (3) Sn-Zn-Al 5 mm 40 mm 0.1 mm RMA Rosin Mildly Activated 240 250260-2 Zn Al Cu Zn Al Cu kcal/j 217 138 178 1.6 1.5 1.9-3 Al Fig.3-Amount of Al addition of solder powder and oxidized film thickness. FUJITSU.54, 2, (03,2003) 157
- - 20 mm/s 5 mm 8 Sn-Zn Sn-8Zn-0.0060Al wt 2-4 Sn-Zn Al 0.0020 0.0100 wt Zn 3.0 14.0 wt Sn-Zn-Al Sn-Zn-AlSn-Pb Cu LQFP Cu 215-5 Sn-Zn 6 m Sn-Zn-Al 1 m 2 m Al Zn 150 1,000 10 N/ LQFP 85 /85 RH 600 Sn-Zn-AlAl Sn-Zn-Al Cu 40 m Sn-Zn-Al -3 53 0.4 mm 24-6 BGA BGA Ball Grid Array Sn-Ag-CuSn- Ag-Cu Sn-Ag-Cu Sn-Zn-Al 760 m Sn-Zn-Al 接合初期 150 100h 放置後 a Sn-Zn 8 ~ ~ ~ 測定不能 240 250 260 濡れ時間 (s) 6 4 2 0 0.001 0.002 0.006 0.01 Al 添加量 (wt%) -4 Sn-8Zn-AlAl Fig.4-Wetting time of Sn-8Zn-Al (wt%) solder. 接合初期 150 100h 放置後 b Sn-Zn-Al -5 Sn-Zn-AlCu Fig.5-Cu plating circuit board jointed interface with Sn-Zn-Al solder. 158 FUJITSU.54, 2, (03,2003)
- - -6 Sn-Zn-Al VL-151VAW Fig.6-Photograph of Fujitsu product. -3 MIL MIL-STD-202F 10 65 / 80 RH 5 80 500 30 80 3,000 10 500 Hz/1.5 mm 200 ppm 10 40 / 90 RH 1,000 25 ボールシェア強度 (N) 20 15 10 5 0 Sn-Zn-Al Sn-Ag-Cu Sn-Pb 0 100 200 300 400 500 600 700 800 900 1,000 150 高温放置時間 (h) -7 Au 760 m Fig.7-760 m Sn-Zn-Al solder ball share strength on Au electrode pad. 215 150-7 90 m -8 CuCu- -8 90 m Sn-Zn-Al Cu Fig.8-90 m Sn-Zn-Al solder ball joint on Cu electrode pad. Zn1 m 500 mn/sn-zn-albga - - - FUJITSU.54, 2, (03,2003) 159
- - 1 - - FUJITSU Vol.51 No.5 p.341-344 2000 2Sn-Zn-Al 11 2001-10 p.247-250 2001 3Sn-Zn-Al 12 2002-10 p.179-182 2002 160 FUJITSU.54, 2, (03,2003)