Dye and Pry Analysis and Testing
- Dye and pry analysis involves submerging a board in a red dye marking fluid under repeated vacuum and venting. This allows the dye to penetrate any cracks or other opens in the solder joints that are exposed to the exterior.
- After bake-out, the components are pulled from the board using a pull tester. Solder joints with pre-existing cracks are marked by the dried red dye.
- Solder joints (board and component sides) are 100% inspected at a minimum of 40X magnification.
- Images are taken showing the board and component sides of each device at 10X to 40X showing representative solder joint locations.
- Dye and pry tests are typically performed on BGA devices, but they will work on any surface mount device.
USES & LIMITATIONS OF DYE AND PRY ANALYSIS:
- What it is great for:
- Best known method to identify cracks, Head-in Pillow defects, or other solder joint separations on a BGA device.
- Allows all solder joints in the array to be tested simultaneously.
- Used to confirm solder joint cracks or pad cratering cracks that cannot be detected by X-ray.
- Destructive test, boards cannot be returned to service. Typically, components for Dye & Pry cannot be evaluated with other methods.
- Manual technique requiring proper sample preparation and interpretation of results.
- Covalent Metrology’s technical staff has over 20 years of experience in Dye & Pry analysis.
PCB assembly after red dye and bake-out. A hex bolt is attached to the device under test using a special epoxy putty and/or adhesive. The board is clamped to the stage and the device is pulled straight up so that no artifacts are introduced.
Board side (Left) and component side (Right) showing solder joint cracks at the board Intermetallic (IMC) layer and board pad lifts (cratering). Fractured BGA solder joints are a Defect per IPC-A-610G, section 8.3.12. Lifted Lands (Pad Cratering) is a defect per IPC-A-610G, section 10.3.2.
Board side (Left) and component side (Right) showing 3 solder joints with a smooth dome marked by red dye, indicating “Head in Pillow” defects. These (non-continuous) solder joints are Defects per IPC-A-610G, section 8.3.12.
Board side (Left) and component side (Right) showing no pre-existing cracks or other separations. The dye adheres to the solder balls and the solder mask windows in the board but does not penetrate the joints. These BGA solder joints are Acceptable from Dye & Pry per IPC-A-610G, section 8.3.12.