What is solder bridge?
Solder Bridging is an issue that arises at the time of soldering. It occurs when component pads on a PCB get connected due to the application of excess solder. Solder bridging is a microscopic phenomenon. Any solder bridge, which goes undetected during inspection, may cause a short-circuit in the component traces.
How do you get rid of solder balls?
- Add solder mask between the pads.
- Design the pads and stencil aperture to the right size.
- Do not mix old and new flux together.
- Adjust the solder paste printing pressure.
- Adjust the pressure for pick and place nozzles.
- Ensure there is a zero print gap between the PCB and the stencil.
How to prevent solder from bridging during assembly?
Additionally, solder mask dams can be added between fine pitch pads to prevent solder from bridging. Solder mask defined pads can also prevent bridging, especially in tight pitch areas like BGAs and LGAs. 2) Modify the reflow profile.
Can a SMT pad be used as a solder bridge?
In case of very tightly spaced pads on a Ball Grid Array (BGA) or Land Grid Array (LGA), there is not enough room to maintain a barrier and mask relief to have a solder mask dam between two SMT pads. If such cases, you can use a solder mask defined pad which provides a solder mask relief that’s the same size as the copper pad it is protecting.
What should solder mask relief be around three pads?
Fig 2: Solder mask relief surrounding three pads, keeping solder from each component separated. While setting up your design rules at the start of your project, its always recommend to do a setting of relief between .003” to .008” for all of your SMT components.
What causes solder to form a conductive path between pads?
Solder Bridging is another common defect, which occurs when the solder has formed an abnormal connection between two or more adjacent traces, pads or pins, and forms a conductive path. There is no solder mask between adjacent pads.