die shift

**Die shift** is the **lateral displacement of die from intended placement coordinates during or after attach process steps** - shift control is required for alignment-critical package features. **What Is Die shift?** - **Definition**: XY position error between programmed die location and actual bonded die location. - **Shift Sources**: Placement offset, substrate movement, adhesive flow forces, and cure-induced drift. - **Critical Interfaces**: Affects bond-pad registration, lid alignment, and optical or MEMS cavity features. - **Detection Tools**: Measured by post-attach vision metrology and package-coordinate mapping. **Why Die shift Matters** - **Interconnect Risk**: Large shift can cause bond-path conflicts and routing violations. - **Yield Impact**: Misplaced die increase probability of shorts, opens, and cosmetic rejects. - **Process Stability**: Shift trends reveal placement-tool calibration or material-flow issues. - **Package Compatibility**: Tight-margin packages have low tolerance for positional drift. - **Cost Exposure**: Shift failures often surface after added assembly value has been invested. **How It Is Used in Practice** - **Tool Calibration**: Maintain placement-camera and stage offset calibration routines. - **Adhesive Control**: Tune rheology and dispense pattern to reduce post-placement drift forces. - **Inline Gatekeeping**: Hold lots when shift distribution exceeds qualified tolerance bands. Die shift is **a critical placement-accuracy KPI in package assembly** - die-shift control is essential for high-yield alignment-sensitive products.