Optimizing the reflow profile via defect mechanism analysis

Authors
Citation
Nc. Lee, Optimizing the reflow profile via defect mechanism analysis, SOLDER S MT, 11(1), 1999, pp. 13-20
Citations number
7
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Eletrical & Eletronics Engineeing
Journal title
SOLDERING & SURFACE MOUNT TECHNOLOGY
ISSN journal
0954-0911 → ACNP
Volume
11
Issue
1
Year of publication
1999
Pages
13 - 20
Database
ISI
SICI code
0954-0911(1999)11:1<13:OTRPVD>2.0.ZU;2-U
Abstract
A reflow profile is proposed which is engineered to optimize soldering perf ormance based on defect mechanism analysis. In general, a slow ramp-up rate is desired in order to minimize hot slump, bridging, tombstoning, skewing, wicking, opens, solder beading, solder balling, and components cracking. A minimized soaking zone reduces voiding, poor wetting, solder balling, and opens. Use of a low peak temperature lessens charring, delamination, interm etallics, leaching, dewetting, and voiding. A rapid cooling rate helps to r educe grain size as well as intermetallic growth, charring. leaching and de wetting. However, a slow cooling rate reduces solder or pad detachment. The optimized profile favors that the temperature ramps up slowly until reachi ng about 180 degrees C, implementation of the optimized profile requires th e support of a heating-efficient reflow technology with a controllable heat ing rate. Emergence of the forced air convection reflow provides a controll able heating rate. in addition, it is not sensitive to variation in parts' features, thus allows the realization of the optimized profile.