|Ask the Experts|
September 14, 2020
Options for Reballing BGA Components
Which of the following do you recommend when reballing BGA components?
Reballing with solder paste and solder spheres, or with solder spheres only?
Would you change the process depending on the size of the BGA component or number of balls?
|Expert Panel Responses|
The appropriatere-balling process to follow is dependent on the BGA package. If you are re-balling a eutectic or lead-free BGA package then using a tacky flux along with the specified alloy solder sphere is the most common approach.
However if the BGA package requires a high temperature solder sphere then applying eutectic solder paste through the use of a stencil, and then placing the high temperature solder sphere may be recommended. The re-balling profile temperature will allow thee utectic solder to reflow and attach the high temperature sphere to the component pad.
We have been successfully reballing BGA devices for years in accordance with IPC 7711 procedure 5.7.3 BGA Reballing Procedure, Fixture Method Flux Only. Our experience would indicate there is no need to change the process with a change in ball size or ball count.
Circuit Technology Center
I would re-ball using spheres and tacky flux. I would not use paste. There are two main reasons for this:
I would recommend re-balling by applying flux first then solder balls. No need to change process depending on ball size.
Vice President Technology
IPC-7711 "Rework, Modification, and Repair of Electronic Assemblies" has several procedures which all indicate that you should use flux and solder spheres to reball the BGA.
Take a look at the latest BGA reballing procedure to be added to the document, procedure 5.7.6 (attached). You'll see that this procedure uses a polyimide ball carrier that matches the layout of the BGA. Simply clean the BGA, Flux the component,align the polyimide carrier and then reflow.
There are several other methods in the guidelines which would be helpful in your situation.
Manager of Assembly Technology
There are a number of viable methods available for reballing BGAs and other area array devices. Ball count, pitch, diameter, alloy and package size are all considerations.
One preferred method that satisfies most reballing applications is the use of flux with a mask (stencil) to accurately position replacement solder spheres onto a package and then reflow in a controlled environment, such as a stand-alone Mini Oven.
Typically an air environment is used, however reballing with an inert environment is gaining popularity,especially reballing smaller devices. Occasionally solder paste is used instead of flux when criteria necessitates increased interconnect solder volumes.
Regional Sales Manager
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