Stencils services Speciality Stencils Screens Blades Rework Tools

Wafer Ball Placement Tooling

 

BGA ball placement at the wafer level has gained popularity and acceptance in recent years. Ball Placement Delivery Systems vary in sophistication from a simple brush sweeping balls into apertures in the Stencil Placement Tool to devoted stencil printing machines with a self-contained ball delivery head. As the delivery system sweeps over the Ball Placement Stencil, BGA balls fill the apertures and are transferred to the wafer when the wafer separates from the Stencil Placement Tool. Normally the Ball Placement Stencil is in direct contact with the wafer during the ball delivery process. Pads on the wafer have tacky flux to hold the balls in place prior and during the reflow process. A photoresist layer is imaged and developed on the back side of the Ball Placement Stencil Tool to prevent contact with the tacky flux during the ball delivery cycle.
Ball Size Aperture Size Stencil Thickness Resist Build-Up Thickness
1214.584
2023146
2527196
3034219
35402312
Note: All dimensions are in mils (0.001")