Chemical distribution systems are networks of pipes and equipment delivering process chemicals and gases to semiconductor manufacturing tools. Scope: Distribute liquid chemicals (acids, solvents, photoresists) and specialty gases to individual process tools. Components: Storage tanks or drums, pumps, filters, pressure regulators, piping, valves, mass flow controllers, point-of-use delivery units. Materials: High-purity piping materials - PTFE, PFA, PVDF for chemicals; electropolished stainless steel or specialty alloys for gases. Purity requirements: Parts per billion (ppb) contamination levels required. Every component must maintain purity. Safety: Double containment for hazardous chemicals, leak detection, automatic shutoffs, exhausted enclosures. Chemical types: Acids (HF, H2SO4, HNO3), bases (NH4OH), solvents (IPA, acetone), photoresists, developers, etchants, CMP slurries. Blending: Some systems blend chemicals or dilute with DI water at delivery. Monitoring: Track chemical usage, purity, and delivery pressure. Automated replenishment.