A 3D cavity stencil is typically manufactured using either an electroforming process or deep step-etching techniques. It is designed for solder paste or material printing on substrates such as PCBs or lead frames that already have mounted components, such as bare dies or other protruding (convex) features.
Unlike standard flat stencils, a 3D cavity stencil includes recessed areas (cavities) that accommodate these pre-mounted components. This allows precise printing directly onto die tops or specific regions without interference from surrounding structures.
Key characteristics:
- Cavity design: Custom recesses to fit over existing components
- High precision fabrication: Often electroformed nickel or chemically etched stainless steel
- Support for uneven surfaces: Enables printing on non-planar substrates
- Improved alignment: Ensures accurate paste deposition in tight or obstructed areas
In some cases, a custom squeeze blade (squeegee) is also designed and fabricated specifically for the stencil. This ensures proper paste transfer across varying heights and helps maintain consistent pressure during printing.
