What causes voids in solder joints?

One major contributor to voiding in solder joints is solder paste. Solder pastes contain ingredients that volatilize during reflow. These volatile materials become gas bubbles that can be trapped in the solder joint. Different solder pastes also wet and spread differently.

What are three common causes of a poor solder joint?

Common Reasons for Solder Joint Failure

• Poor solder joint design. There are various types of solder joints to choose from when soldering electronic connections.
• Poor-quality soldering.
• Low-quality solder materials.
• Unintended stresses from polymeric materials.
• Tensile fracture.
• Creep failure.
• Fatigue failure.
• Corrosion.

How do you fix soldering void?

1. Reduce the amount of solder paste deposited.
2. For large pads, use small opening grids instead of a large aperture.
3. Extend the preheat time so it is long enough.
4. Extend the soak zone time so it is long enough.
5. Always consider new solder paste for BGA assembly.

What is the cause of voiding in SMT?

Generally, the voids are caused by the outgassing of entrapped flux in the sandwiched solder during reflow. Voiding is also a function of the timing between the coalescing of solder powder and the elimination of immobile metallisation oxide. The sooner the paste coalescence occurs, the worse the voiding will be.

How does voiding affect the integrity of solder joints?

The impact of voiding on the solder joint integrity of ball grid arrays (BGAs)/chip scale packages (CSPs) can be a topic of lengthy and energetic discussion. Detailed industry investigations have shown that voids have little effect on solder joint integrity unless they fall into specific location/geometry configurations.

Can a non BGA solder joint be voided?

According to IPC guidelines, the allowable level and size of non-BGA solder voids are simply to be specified by customer agreement. In the absence of well defined voiding criteria though, the morphology of solder joint fillets seen in final visual inspection often becomes the sole arbiter of solder workmanship and quality.

Why are voids always found in solder paste?

Smaller macrovoids on the boundary between the solder and the PCB pad pose a higher reliability risk than a larger macrovoid located in the center of the joint [25], [28]. Inevitably there will be always voids in the joint made using solder paste due to the physical structure of the paste.

Are there voids in the ball grid array solder joints?

Solder voiding in ball grid array (BGA) solder joints has been well characterized and documented in IPC-A-610 and IPC-7095 which define industry recommended BGA solder workmanship criteria and methods of inspection.