Ultra low voiding solder paste - Alpha OM362

What does voids in a solder joint mean and what is the solution?

One of the big challenges in electronic assembly is voiding in a solder joint and its effect on performance and the long-term reliability of the device.

What does a void in a solder joint mean?

Voiding in a solder joint refers to gaps, open pockets, or empty spaces within the solder joint.
Voiding is typically caused by entrapped gasses or paste flux residues that were not able to escape during the reflow process.
This is because the exterior or perimeter of the solder joint begins cooling or transitioning from the liquidous to solidus stage during reflow before the remaining gasses from the paste flux has a chance to fully outgas, thus creating “bubbles” inside the solder joint.

Why are voids in solder joints an issue in electronics assembly?

Voids create a mechanical weakness in the structure of the solder joint which can affect the overall performance or even the long-term reliability and operational performance of the device.
During power cycling, these “gaps” in the solder joint create “hot spots” which can further degrade the mechanical robustness of the solder joint and thus negatively impact performance.

How can we address voiding in the solder joint?

Voiding levels are primarily influenced by either the process conditions the solder joint was created under and/or the paste flux chemistry.
Both have limitations regarding the amount of influence (positively and negatively) they have on the overall level of voiding for a given solder joint.
While there are other factors that can negatively influence voiding such as surface finish, excessive peak temperature during the reflow process (for specific paste flux chemistries), entrapped moisture, etc., however the two main causes are the reflow process set up and the paste flux chemistry itself.

To achieve the next level in voiding performance, we need to also look at the chemistry and the impact it can have on improving voiding performance.

Because solder paste flux chemistry is also a critical factor in solder joint void performance, new generations of solder paste flux chemistry are required to help minimize the creation of voids while still being able to provide good wetting, excellent electrochemical migration resistance and post reflow cosmetics.

Why ALPHA OM-362 Solder Paste?

ALPHA OM-362 is the next generation ultra-low voiding solder paste that is IPC-JSTD-004B ROL0, lead-free and zero-halogen, no-clean. It provides a 50% reduction in voiding levels vs conventional solder pastes with Innolot as well as traditional SAC alloys, on all component types, including bottom terminated components.

ALPHA OM-362 achieves IPC-7095 Class III voiding on BGA components, exceeds multiple other industry voiding standards and can provide voiding levels averaging less than 10% voiding on bottom terminated components.

ALPHA OM-362 chemistry makeup was specifically designed to provide:

Best-in-class voiding performance to increase process stability, and thermal, and electrical performance of the most demanding component applications.

Excellent SIR / Electrochemical migration performance to ensure electrical reliability & functionality of fine-pitched components.

Wide Reflow Profile Window enabling high quality solderability of complicated, high density PCB assemblies using straight ramp and soak profiles, as high as 150 to 200 °C soak.

Good Coalescence and Wetting Performance down to >200μm exhibiting good wetting characteristics and solder joint reliability.
Excellent Solder Joint and Flux Residue Cosmetics providing clear flux residue with good ICT.
Recommended for applications where voiding is the primary concern due to the application.

For further information, or to arrange your onsite trials, please contact our technical sales team to discuss.

Email : sales@ams-electronics.co.uk

Phone : 01260 270 950

What does voids in a solder joint mean and what is the solution?

One of the big challenges in electronic assembly is voiding in a solder joint and its effect on performance and the long-term reliability of the device.

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