lead time

Lead time is the duration from placing an order to receiving delivery, a critical planning parameter for semiconductor manufacturing materials, equipment, and customer products. Lead time categories: (1) Equipment lead time—12-24 months for new tools (EUV scanners 18-24 months, etch/CVD 9-15 months); (2) Material lead time—4-12 weeks for chemicals and gases, 8-16 weeks for specialty materials; (3) Wafer fabrication cycle time—6-12 weeks for wafer processing (more layers = longer); (4) Packaging and test—2-4 weeks; (5) Customer order to delivery—8-26 weeks depending on product and priority. Wafer cycle time components: (1) Queue time—waiting for tool availability (largest component, 60-80%); (2) Process time—actual processing on tool; (3) Transport time—AMHS movement between tools; (4) Hold time—waiting for metrology/engineering disposition. Cycle time reduction: (1) Bottleneck management—increase capacity at constraints; (2) WIP management—control wafer starts to reduce queues; (3) Hot lot management—priority lots with expedited routing; (4) Automation—reduce manual handling delays. Lead time impact: (1) Inventory planning—longer lead time requires more safety stock; (2) Demand response—can't quickly adjust to market changes; (3) Customer satisfaction—shorter lead time is competitive advantage. 2021-2022 crisis: lead times extended to 52+ weeks for some chips, automotive and industrial severely impacted. Capacity planning: must forecast demand 1-2 years ahead due to equipment lead times. Lead time reduction is a continuous improvement focus—shorter lead times improve responsiveness, reduce inventory costs, and increase customer competitiveness.