Adjustment of Equipment Inspection Frequency in Special Scenarios

① New Equipment/After Major Overhaul: For the initial 3 months, intensified inspections are required (recommended weekly inspections; the regular frequency is typically monthly). Key inspection focuses include: sealing integrity (to prevent chemical leakage), chemical delivery accuracy (flow rate/concentration stability), chamber cleanliness (particle/metal impurity content), and wafer processing uniformity. Regular inspection frequency may be restored only after all indicators remain stable without fluctuations and process yield stays consistent for more than one consecutive month.

② Process Change: When switching to higher-purity chemicals (e.g., from BOE to diluted HF) or new process formulations, immediate special inspections are required. In addition to verifying the stability of equipment operating parameters, special attention must be paid to inspecting: material compatibility of pipelines/chambers (corrosion resistance, prevention of leached impurities), purification effect of the chemical filtration system, and uniformity of spray/rinsing units. Special inspections must track the yield data of at least 3 batches of wafers continuously; routine monitoring can be integrated only after confirming no abnormalities.

③ After Abnormal Events: After abnormal events such as chemical leaks or sudden drops in process yield (e.g., exceeding limits of wafer particles/metal impurities), immediate shutdown for comprehensive inspection is required. For leak incidents, priority should be given to checking seals, valve cores, pipeline welds, and flange connections. For sudden yield drops (exceeding particle/metal impurity limits), priority should be given to checking the chamber cleaning module, spray head clogging, filter cartridge lifespan, chemical purification device, and cleanliness of the wafer transfer robot arm. After passing the comprehensive inspection, production can resume only after confirming no abnormalities through trial runs with dummy wafers + small-batch actual wafer verification.

④ Change of Chemical Batch/Supplier: When replacing corrosive chemicals (e.g., HF, sulfuric acid) from different suppliers or batches, intensified inspection for 1–2 batches is required, with a focus on verifying the compatibility between the chemicals and equipment materials, and the impact of impurity content on the process.

⑤ Restart After Long-Term Shutdown: For equipment that has been shut down for more than 15 days (especially wet etching/cleaning equipment), before restarting, it is necessary to inspect pipeline crystallization blockage, aging degree of seals, and chamber cleanliness to avoid leakage or particle contamination after startup.