Surgeon grade rework and repair, by the book and guaranteed.®
Newsletter | Contact Us
Phone: 978-374-5000
Solder Mask Rework at a BGA Site More Features
Every now and then an error will occur at the most inopportune time; in this case it was in the design phase of the printed circuit board.

Solder Mask Rework at a BGA Site
Epoxy or mask needs to be applied to the conductor between the BGA pad and connecting plated hole or via.
When circuit boards are in the proto-type phase, it is not uncommon for sockets to be used at BGA sites. Design Engineers must layout the BGA sites to meet the requirements of the selected test socket. Many of these sockets rely on a flat surface that precludes the use of solder mask.

Eliminating solder mask is fine until it is time to move on with production when BGA components will be soldered directly eliminating the socket. You're probably not surprised that there is an occasional blunder at this point. In this case, someone neglected to re-layout the solder mask layer. Have you tried soldering a BGA component onto an unmasked BGA site?

The primary purpose of solder mask at a BGA site is to isolate solder wetting to a specific area, the BGA pad. Solder mask is used to isolates the pad from the conductor, or from the circuit leading to a via or plated hole. Without the solder mask, the molten solder will bleed away onto the connecting pad, or into the attached vias. Solder joint opens and shorts are a guarantee.

Solder Mask Rework at a BGA Site
Two part epoxy is commonly used in place of solder mask.
The obvious key to preventing this would have been to re-layout the mask layer. Since that was not done, solving the missing mask issue can be approached in a few different ways, but the fact is, it must be confronted. Here are a few options:

Option One:
Scrap, a major ouch to the pocketbook.

Option Two:
Use the same socket that was used during the prototype phase. This is probably not a practical solution, but it can be pursued. BGA sockets tend to be expensive and the durability of the connection can be a concern.

Option Three:
Rework the solder mask at the site. This can be accomplished in a few ways. The most common method is to manually apply the solder mask, or an equivalent high temperature epoxy, to the site.

Prior to applying the mask the surface must also be thoroughly cleaned to eliminate any contaminates and optimize the adhesion of the mask to the surface.

Solder Mask Rework at a BGA Site
Inexpensive and disposable Micro Probes are ideal for dispensing a tiny drop of epoxy for mask rework.
Complete coverage of the site is not always necessary, the key is creating the isolation barrier and this can sometimes be accomplished with a much smaller application of mask at the connecting circuit while leaving the adjacent area clear.

This technique takes a steady hand, and the use of a variety of tools, including a controlled dispensing system, or fine tipped probes, along with tape or a template to shield the solder mask from reaching any undesired locations.

This can be a tedious and time-consuming process, but is essential if you expect to place and reflow BGA component without headaches.
Several members of the Circuit Technology Center team contributed to this feature story.
Questions / Comments?
Call 978-374-5000 or submit your questions, comments and requests using the form below.

Your Name

Your E-mail

Your Phone

Your Company

Your Country

Send us a file

Maximum file size 4 megabytes.


Customer Comments
We just received our repair circuit boards. They look great. Nice job!!"
J.M. Wilmington, MA USA
Robotic BGA Solder Ball Removal
Robotic BGA Solder Ball Removal
Watch a video that shows robotic BGA component deballing. This precision process is highly reliable when preparing BGA components for reballing.
Learn more ...
BGA Component Reball Video
BGA Component Reball Video
Video demonstrates robotic BGA component deballing. This precision process is highly reliable when preparing BGA components for reballing.
Learn more ...
Tough Engineering Changes?
Tough Engineering Changes?
Engineering changes are a reality that need to be dealt with. Do you have qualified rework technicians to do the job efficiently and reliably?
Learn more ...
Epoxy Packs Eliminate Measuring
Epoxy Packs Eliminate Measuring
This unique kit contains 10 packages of super strength epoxy, precisely measured out into two-compartment plastic packages.
Learn more ...
About Us | Base Board Repair | BGA Reballing | BGA Rework | Coating/Marking | Circuit Repair | Component Salvage | Conflict Minerals | Contact Us | Copyright/Disclaimer | Directions | ECO/Modification | Feature Articles | Frequent Questions | Gold Contacts | Inspection | Order Tracking | Newsletter | Plated Hole Repair | Prices, Terms, Delivery | Products | Privacy | REACH | RoHS | Services | SMT/BGA Repair | SMT/PTH Rework | Sitemap

Circuit Technology Center, Inc.
22 Parkridge Road
Haverhill, MA 01835 USA
Copyright © Circuit Technology Center, Inc.. All rights reserved.