Issue link: https://iconnect007.uberflip.com/i/1547450
44 SMT007 MAGAZINE I NOVEMBER 2026 BGA devices provide high I/O density and compact package size, but their hidden solder joints make rework challenging. Successful replacement depends on controlling site prepara- tion, solder deposition, placement, and reflow. One of the simplest tools in that process is the rework stencil. I view it as a process-control tool rather than simply a way to put paste on a board. Its design affects solder volume, print consistency, and sometimes component alignment. When Should Solder Paste Be Used? A question that comes up frequently is whether solder paste should always be printed on the PCB before placing a replacement BGA. At BEST, we do not BY N AS H B E L L , B EST, I N C. The Use of BGA Rework Stencils K N O C K I N G D OW N T H E B O N E P I L E automatically apply solder paste for every standard BGA placement. For most BGAs with collapsible solder balls, our normal process is to use an appropriate tacky flux and rely on the solder already present on the component to form the joint during reflow. We typically add solder paste when a customer specifically requests it or when there is a clear process reason to do so. There is not one universal rule requiring paste for every BGA rework. The method depends on the package, land geometry, customer requirements, and qualified process. My preference is not to add another process variable unless it provides a clear benefit; paste printing introduces stencil thickness, aperture size, alignment, and deposit volume as additional variables. Figure 1: Stencil thickness controls the height of the solder paste deposit, while aperture diameter is generally based on the PCB pad size.