scan compression edt

**Scan Compression with EDT** is the **DFT architecture that shrinks external test data volume while maintaining high fault coverage**. **What It Covers** - **Core concept**: uses decompressor and compactor logic around scan chains. - **Engineering focus**: reduces tester memory and test application time. - **Operational impact**: enables large SoC production test at lower cost. - **Primary risk**: x masking and aliasing must be controlled. **Implementation Checklist** - Define measurable targets for performance, yield, reliability, and cost before integration. - Instrument the flow with inline metrology or runtime telemetry so drift is detected early. - Use split lots or controlled experiments to validate process windows before volume deployment. - Feed learning back into design rules, runbooks, and qualification criteria. **Common Tradeoffs** | Priority | Upside | Cost | |--------|--------|------| | Performance | Higher throughput or lower latency | More integration complexity | | Yield | Better defect tolerance and stability | Extra margin or additional cycle time | | Cost | Lower total ownership cost at scale | Slower peak optimization in early phases | Scan Compression with EDT is **a practical lever for predictable scaling** because teams can convert this topic into clear controls, signoff gates, and production KPIs.