User's Manual

Page 45
BitaTek Co., Ltd. Copyright protected. All rights reserved.
NO. 115 Wugong 3rd Rd., Tel [phone]
Wugu Dist., New Taipei City 248, Taiwan (R.O.C.) Fax[phone]
It is recommended that customers do their own testing to determine the optimal solder paste
volume. This volume can be applied by stencil printing with different stencil heights to fit your
existing assembly needs. The volume is kept constant by varying the aperture size
accordingly.
The most common thicknesses 110μm and 150μm (stainless steel, laser cut) have been
tested with good results with regard to printing process, soldering process and reliability
testing. Similar results are expected with stencil thicknesses in between.
Different solder paste volumes have been tested too but with much lower volume there is a
trend to poor solder joints and a risk for open joints. Much larger solder joints tend to form
solder balling in the vicinity of the solder joints.
4.2.2. Used Parameters and Recommendations
For stencil printing, a stainless steel stencil, laser cut (or similar technology) should be used.
Parameters must be optimized depending on actual application board design, equipment und
solder paste.
To simulate different applications, two different stencil thicknesses of 110μm and 150μm
were used while keeping the solder paste volume constant by variation of the apertures.
If the results for all tested versions were found to be good. For exact pad and aperture
dimensions, as well as module geometry and footprint design
4.2.3. Pick and Place
FREY M1 well be put into the antistatic tray plate. One antistatic tray plate will have 15 Frey
M1 modules, and one moisture barrier bag will have max 5 antistatic tray plates
4.2.4. Reflow Profile
Short profiles are recommended for reflow soldering processes in order to prevent top side
solder joints from growing large intermetallic compounds. Peak zone temperature should be
adjusted high enough to ensure proper wetting and optimized forming of solder joints. On the
other hand, a plateau during preheating can help to reduce voiding behavior. Generally
speaking, unnecessary long exposure and exposure to more than 245°C should be avoided.