Circuit Technology Center and Keysight Technologies have teamed up to provide the test world with a complete turn-key approach for testing DIMMS directly at BGA component sites.
Keysight Technologies W2630A series DDR2 BGA probes enable probing embedded memory DIMMs directly at the ball grid array with the Keysight Technologies logic analyzers and oscilloscopes. Although this dynamic product is available to support Engineers through the test process, it does take some skillful attention.
This procedure provides an overview of installing Keysight Technologies DDR2 DRAM BGA Probes onto circuit board assemblies.
Operator Skills
The DDR2 BGA Probe installation is a challenging process to complete. The engineer or operator must have BGA rework experience. Reballing of the DDR2 BGA Probe is required for placement onto the circuit board. This process also requires experience and skill.
Initial removal of BGA component.
Equipment
BGA reballing kit or system for component and probe solder ball attachment.
Solder paste stencil for circuit board site preparation.
Hot gas rework station designed for BGA component rework.
Microscope with an oblique view for perimeter inspection.
X-ray inspection system for post-placement inspection.
Here are the steps.
BGA removal from circuit board.
Small corner section of BGA site prior to removal of residual solder.
The process for safe removal of the BGA component is completed with a Hot Gas Rework Station. The circuit board may require additional preparation, such as baking and masking the area adjacent to the rework site. To prevent damage, you must closely monitor the temperature of the circuit board with thermocouples during the removal cycle.
Circuit board site cleaning.
After the component has been safely removed from the circuit board, the component and site must be prepared for the probe placement and the BGA onto the probe. The circuit board and component site cleaning are completed with a vacuum de-soldering nozzle that removes all residual solder from the sites.
Solder ball application to Probe and component.
Probe place onto circuit board assembly.
The placement of solder balls on the probe and re-balling of the BGA component must be completed before placement on the circuit board. For this process, a specially designed tool for re-balling is used along with specific stencils and solder balls to match the probe layout and BGA component.
Placement of Probe onto the circuit board.
Installation of the Probe onto the circuit board is completed with a Hot Gas Rework System. Solder paste must be applied to the site before placement of the Probe. This process is completed with a solder stencil. The heat application is controlled using a unique repeatable temperature profile for each circuit board.
Placement of BGA onto the Probe.
Installation of the BGA onto the probe is also completed with the hot gas rework system, which is very similar to the probe placement.
Completed BGA placement onto probe.
The application of heat is controlled by using a repeatable temperature profile. Solder paste must be applied to the site before placement of the Probe. This process is completed with a solder stencil.
Inspection to confirm soldering process.
Like any BGA application, inspecting the solder joints requires an X-ray system.
X-ray of the Probe interface to the circuit board and the BGA component to the Probe is required to inspect for solder bridges, voids, and misalignment. Perimeter inspection can be completed with a microscope or inspection camera.
Several members of the Circuit Technology Center team contributed to this feature story.
