Electronics Forum | Thu Nov 01 05:30:06 EST 2001 | wbu
This is not about the physical laws but besides contamination, which will actually IMO cause NO WETTING, it is quite vital that the time-limit the flux is active is not exceeded during your reflow process. Depending on your paste/flux you will have a
Electronics Forum | Thu Nov 01 12:13:10 EST 2001 | jonathan
I guess this clarifies the defect more then looks at the process, but I�ll just through it out there for the sake of learning something new. If anyone would comment on this please feel free�. There are many different varieties of dewetting defects.
Technical Library | 2013-02-07 17:01:46.0
Silicone contamination is known to have a negative impact on assembly processes such as soldering, adhesive bonding, coating, and wire bonding. In particular, silicone is known to cause de-wetting of materials from surfaces and can result in adhesive failures. There are many sources for silicone contamination with common sources being mold releases or lubricants on manufacturing tools, offgassing during cure of silicone paste adhesives, and residue from pressure sensitive tape. This effort addresses silicone contamination by quantifying adhesive effects under known silicone contaminations. The first step in this effort identified an FT-IR spectroscopic detection limit for surface silicone utilizing the area under the 1263 cm-1 (Si-CH3) absorbance peak as a function of concentration (µg/cm2). The next step was to pre-contaminate surfaces with known concentrations of silicone oil and assess the effects on surface wetting and adhesion. This information will be used to establish guidelines for silicone contamination in different manufacturing areas within Harris Corporation... First published in the 2012 IPC APEX EXPO technical conference proceedings.
| http://etasmt.com/cc?ID=te_news_bulletin,23572&url=_print
. Process and design-related causes: • Excessive volume of solder due to improper pad dimension • Excessive volume of solder due to improper stencil aperture