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BGA vs LGA. Which to choose?

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#74683

BGA vs LGA. Which to choose? | 5 October, 2015

We are planning on using a chip that is available in LGA or Sn/Pb balled BGA. The package dimensions are the same. Pitch = 1.27mm. We are using a Sn/Pb soldering process and no clean paste (wash afterward) for high reliability Class 3 assemblies. Fairly low volume. Geometry is 7x11 balls. X-ray inspection is a given.

We have had one design with an LGA. Some concerns with voiding. We have never done a BGA but we will have to jump in at some point. What are the pros/cons of each package? Which is more challenging for assembly? Thank you.

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#74684

BGA vs LGA. Which to choose? | 5 October, 2015

Washing no-clean solder residue out from under BGA's might present a challenge.

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#74690

BGA vs LGA. Which to choose? | 6 October, 2015

Agree. However the LGA has an even lower standoff, so I would think it would be an even greater challenge.

The LGA is a cheaper choice but want to know from those who have done both if the extra cost of the SnPb BGA would pay for itself in lower rework (and associated) assembly costs overall. Which one is easier to process?

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#74702

BGA vs LGA. Which to choose? | 8 October, 2015

BGA's are by far much easier to process correctly and inspect.

As for LGA's you'll never get 100% of the materiel out from under it during the cleaning process. The voiding issue is magnified with and LGA, the low standoff is the reason for the voids, there's not enough clearance to allow enough out gassing. Your basically looking at a bunch of smaller pads (bigger than a BGA pattern) that has comparable voiding the ground on QFN's. LGA's have such a low standoff any extra inspection outside of X-Ray is impossible.

**Edited forgot about your Class 3 requirement...

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