Sponsor

ASYMTEK Select Coat SL-1040
The SL-1040 Conformal Coating System upgrades the SL-940 and added significant system-level advancements to elevate automation, control, precision & preventative maintenance for better yield.
Nordson Electronics Solutions

Sponsor

Eliminate Worry of Cross Contamination
While Models 529 and 1550 are similar semi-automatic cleaners with single wash and rinse tanks, the Model 2003 includes 2 wash tanks for cleaning multiple applications in one machine.
Smart Sonic

Ask the Experts

June 17, 2009 - Updated
June 14, 2009 - Originally Posted

Solder Joint Void Limit for BGA Components

What is a reject limit for BGA component solder joint voids in lead free class 2 circuit board assemblies? What can we do to reduce voids in our lead free BGA components?

C. K.

Expert Panel Responses

The void requirement is that the sum of all of the voids cannot equal more than 25% of the cross-sectional area of the solder joint. Anything higher than 25% should result in a reject. Voids can be impacted by several factors. In many cases, a modification of the reflow profile can reduce voids significantly. The targeted profile for minimizing voiding would be a long, high soak and a lower peak temperature. The long, high soak temperature is particularly critical to provide sufficient time for the volatiles in the paste flux to evaporate prior to reflow. We have also learned that differences in paste characteristics can drive differences in voiding behavior. If you are experiencing a significant void rate even if with an optimized profile, an evaluation of other paste products may be beneficial.

Brian Smith
General Manager - Electronic Assembly Americas
DEK International

Mr. Smith has been supporting customers in the electronics assembly industry since 1994. His expertise is focused on solder paste printing and reducing soldering defects. He holds a BS in Chemical Engineering and an MBA in Marketing. He has authored several papers in trade magazines and at industry conferences. He is an SMTA Certified Process Engineer.

Solder joint void limit for BGA components is 12.25 % area for lead free class 2 circuit board assemblies. Most of the voids come from out gassing of the chemicals in the flux. To reduce voids change the chemicals in the formulations that create the out gassing.

Mike Scimeca
President
FCT Assembly

Mike Scimeca created FCT Assembly after the purchase of Fine Line Stencil, Inc., and consists of two major operations: stencil manufacturing and the manufacturing of electronic assembly products such as solder paste, flux and solder bar.

Submit A Comment

Comments are reviewed prior to posting. You must include your full name to have your comments posted. We will not post your email address.

Free Newsletter Subscription
Circuitnet is built for professionals who bear the responsibility of looking ahead, imagining the future, and preparing for it.

Insert Your Email Address

Sponsor

The Industry Standard Solder Paste
Looking to Avoid the Void® and enhance SIR performance? Indium8.9HF is your proven, versatile and stable, no-clean, halogen-free, Pb-free solder paste solution.
Indium Corporation