The semiconductor supply chain is the complex global network of suppliers providing materials, equipment, chemicals, gases, substrates, packaging, and services essential for chip manufacturing. Supply chain tiers: (1) Tier 1—direct suppliers (equipment makers, substrate vendors, chemical suppliers); (2) Tier 2—component suppliers to Tier 1 (optics, ceramic parts, specialty chemicals); (3) Tier 3—raw material suppliers (rare earths, high-purity metals, specialty gases). Key supply chain segments: (1) Equipment—ASML (EUV lithography), Applied Materials, Lam Research, Tokyo Electron, KLA (metrology/inspection); (2) Silicon wafers—Shin-Etsu, SUMCO, Siltronic, SK Siltron; (3) Photomasks—Toppan, DNP, Photronics; (4) Chemicals—Entegris, JSR, Fujifilm, TOK (photoresists); (5) Gases—Air Liquide, Linde, Air Products (bulk and specialty); (6) Substrates/packaging—ASE, Amkor, JCET (OSAT). Geographic concentration risks: (1) ASML (Netherlands)—sole EUV supplier; (2) TSMC (Taiwan)—60%+ advanced logic; (3) Japan—70%+ photoresist supply; (4) Russia/Ukraine—neon gas for lasers (pre-diversification). Supply chain disruptions: 2021 chip shortage exposed vulnerabilities—single-source dependencies, long lead times (equipment 12-18 months), limited inventory buffers. Resilience strategies: (1) Dual sourcing—qualify multiple suppliers; (2) Strategic inventory—safety stock for critical materials; (3) Regionalization—build supply chains closer to fabs; (4) Long-term agreements—secure capacity commitments. Industry response: CHIPS Act, EU Chips Act driving supply chain regionalization. The semiconductor supply chain's extreme specialization and geographic concentration make it simultaneously the world's most sophisticated and most vulnerable industrial ecosystem.