silicon

**Silicon Interposer 2.5D** is **passive silicon substrate with embedded interconnects routing signals between chiplets, enabling heterogeneous integration** — dense signal routing layer. **Function** bridges chiplets: receives, routes, delivers signals. **Through-Silicon Vias** vertical copper vias (10-50 μm diameter) route signals/power. **TSV Pitch** 10-100 μm via spacing. Finer: higher density. **Micro-Bumps** chiplets bonded via micro-bumps (10-20 μm pitch). **Copper Bonding** direct Cu-Cu bonding low-resistance interface. **Substrate Thickness** 100-200 μm silicon; mechanically robust, thermally conductive. **Metal Layers** multiple interconnect layers (M1-M6) for routing. **Routing Density** fine-pitch wires enable complex routing between dozens of chiplets. **Signal Integrity** impedance-controlled traces; crosstalk mitigation. **Power Delivery** dedicated power/ground vias; low impedance distribution. **Clock Distribution** low-skew tree distributes clock. **Test** integrated test logic enables testing interposer, connectivity. **Thermal** silicon conducts heat downward; 10-50°C junction temperature improvement. **Thermal Vias** extra vias for heat dissipation under hot spots. **Mechanical** silicon rigid; warping minimal. Supports chiplets. **Stress** CTE mismatch creates stress; underfill mitigates. **Reliability** TSVs stress at via; thermal cycling life important. **Cost** scales with TSV density, yield. **Rework** defective chiplets thermally reworked; interposer reused. **Silicon interposers enable high-density 2.5D integration** for advanced systems.