Title :
An assessment of lead free solder (Sn3.7Ag0.8Cu) wettability
Author :
Chung, C. Key ; Mustapha, Faizul ; Hua, Fay ; Aspandiar, Raiyo
Author_Institution :
Manuf. Technol. Manuf. Malaysia, Kulim, Malaysia
Abstract :
The National Electronics Manufacturing Initiative (NEMI) standardized lead free solder tin/silver/copper (SnAgCu) ternary system in January 2000. This Sn3.7Ag0.8Cu has higher melting temperature of 217°C as compared with current eutectic tin/lead solder (63Sn/37Pb; 183°C). Thus, it is a challenge to electronic lead free packaging that requires higher reflow temperature. Optimizing lead-free-reflow-soldering process in second level interconnection is a critical step to ensure reliable solder joint is properly manufactured. This paper presents the assessment of lead free solder wettability. It covers a wide range of soldering parameters with 4 dominant factors and 14 variables. They are 4 different printed circuit board surface coatings (organic surface preservative, OSP; immersion silver, ImAg; electroless nickel immersion gold, ENIG and tin/lead hot air solder leveling), 4 different fluxes in SnAgCu solder pastes, 3 different reflow peak temperatures (225°C, 230°C and 235°C) and 3 different ranges of time above liquidous (30-60s, 60-90s and 120-150s). A test board is designed in these studies. Wetting angles are output parameters and measured using a noncontact laser measurement system.
Keywords :
copper alloys; electroless deposition; measurement by laser beam; packaging; printed circuit manufacture; reflow soldering; silver alloys; tin alloys; wetting; 120 to 150 s; 217 degC; 225 to 235 degC; 30 to 60 s; 60 to 90 s; SnAgCu; electroless nickel immersion gold; hot air solder leveling; immersion silver; lead free solder; noncontact laser measurement system; output parameters; packaging; printed circuit board; reflow peak temperatures; reflow temperature; second level interconnection; solder pastes; soldering parameters; surface coatings; test board; wettability; wetting angles; Copper; Electronics packaging; Environmentally friendly manufacturing techniques; Integrated circuit interconnections; Lead; Manufacturing processes; Silver; Soldering; Temperature; Tin;
Conference_Titel :
Electronics Packaging Technology Conference, 2002. 4th
Print_ISBN :
0-7803-7435-5
DOI :
10.1109/EPTC.2002.1185587
