BGA Intermittent Connections
BGA intermittent connections or BICs are one of the common mistakes among embedded PCB design defects. In this article, EPCB will tell you how to avoid the unnecessary trouble, and hope it is useful for you.
BIC is a less perfect thermal profile used to adjust reflow soldering and is the basic reason for most embedded design defects. Thermal profile accuracy is determined by the following factors, including PCB layers, thickness, dimensions, number of planes, PCB material type, and component types.
Untented vias and poorly defined stencil apertures also can cause BICs. If stencil apertures aren’t designed properly, too much or too little solder paste is dispensed at certain BGA solder points, then BICs are caused. As to untented vias, fresh embedded designers tend to place vias next to BGA pads or around BGA peripheries. This incorrect design leads to a bad perfect reflow soldering, because when reflowing, solder is sucked into vias instead of being applied to the BGA balls. So dispense less paste on the BGA’s balls in the reflow oven cause BGA with voids.
All in all, you should mask or tent BGA vias at the embedded design and layout level. If you forgot, it’s ok because a design-for-manufacture check mapped out at the planning stages can catch this issue. Otherwise, reflow becomes a major challenge and undetected vias with solder paste traces can cause troublesome BGA intermittent connections.