Comparison of Cleanrooms in Different Industries and Acceptance of Key Nodes

1. Overview of Core Cleanroom Standard Systems

Cleanrooms are foundational supporting facilities for advanced manufacturing. By precisely controlling particles, microorganisms, temperature, humidity, and pressure differences, they provide stable and controllable production environments that directly affect product yield and performance. Four major standard systems are widely adopted globally:

1. ISO 14644 (International Standard)

Focuses on airborne particle concentration control and classifies cleanrooms from Class 1 to Class 9 by particle size and count. The 2015 revision eliminates static/dynamic classification and emphasizes particle monitoring under operational conditions, aligning closer to real production scenarios.

2. Chinese National Standards (GB)

Revised based on ISO 14644:2015, with added microbial control requirements tailored to domestic pharmaceutical and electronic industries. It adopts a dual-index evaluation system (cleanliness + microbiological class) for design and acceptance of new or renovated clean plants.

3. FDA 21 CFR Part 211 (U.S. Pharmaceutical Regulation)

Uses Grade A/B/C/D grading for pharmaceutical cleanrooms, focusing on microbial control (airborne, settle, and surface microorganisms). It aligns with ISO classes (e.g., Grade A dynamic = ISO Class 5) and stresses process control under Quality by Design (QbD).

4. EU GMP Annex 1 (EU Sterile Medicine Regulation)

Similar grading to FDA but stricter on airflow, pressure gradients, and gowning procedures. The 2020 revision strengthens links between sterile process simulation (media fill) and particle monitoring, requiring quantitative microbial risk assessment.

2. Core Parameter Comparison of Cleanrooms by Industry

(1) Semiconductor Industry: Ultra-High Particle Control

Semiconductor cleanrooms have the strictest cleanliness requirements. A 0.1μm particle can short transistors in 7nm processes, so core zones require ISO Class 1–3 microenvironment control with molecular contamination (AMC) controlled at ppb levels.

• ISO 1–3: EUV lithography, mask fabrication; 7nm/5nm/3nm chips, 3D NAND >100 layers
• ISO 5: DUV lithography, ion implantation; 28nm+ mature nodes, automotive chips
• ISO 6: Dry etching, CVD; consumer electronics chips, power management ICs
• ISO 7–8: Sputtering, packaging & testing; low-end memory, consumer sensors

Environmental requirements: 22°C ±0.5°C, RH 45% ±5%, pressure difference ≥5 Pa, unidirectional airflow velocity 0.36–0.54 m/s, with strict control of vibration and static electricity.

(2) Biomedical Industry: Dual Control of Particles and Microbes

Biomedical cleanrooms control both particles and microorganisms to ensure drug safety and efficacy, complying with FDA, EU GMP, and China GMP.

• Grade A / ISO Class 5: Core sterile production (filling, lyophilization)
• Grade B / ISO Class 5 (static): Background zone for Grade A
• Grade C / ISO Class 7: Non-sterile production, packaging preparation
• Grade D / ISO Class 8: Raw material weighing, cleaning

Environmental requirements: 20–24°C, RH 45%–60%, pressure difference ≥10 Pa, unidirectional airflow 0.35–0.5 m/s, ≥20 air changes/h. Dynamic airborne microbes in Grade A ≤1 CFU/m³.

(3) New Energy Industry: Low Dew Point & Energy Efficiency

With solid-state battery and hydrogen industrialization, new energy cleanrooms demand tighter low-dew-point control and carbon reduction, complying with SEMI S2.

Core requirements: Dew point ≤-45°C for lithium battery granulation; ≤-80°C for high-end solid-state batteries; accuracy ±2°C. Energy consumption reduced by 22% vs. 2024; energy recovery ≥65%.

Technical trends: BIM + digital twin (58% adoption) shortens design cycles by 45% and cuts energy use by 22%. AIoT monitoring enables millisecond-level response for stable production.

3. Key Acceptance Points for Cleanrooms

(1) Air Purification System Acceptance

1. Filter Leak Detection: 100% scanning by PAO method for HEPA/ULPA filters.
2. Airflow Validation: Unidirectional airflow velocity uniformity within ±20%; non-unidirectional airflow verified by smoke visualization to avoid eddies.
3. Recovery Time: Cleanliness recovery time ≤15 minutes after maximum pollution release.

(2) Environmental Parameter Validation

1. Temperature & Humidity: 3 consecutive days of dynamic monitoring; temperature fluctuation ≤±1°C, RH ≤±5%.
2. Pressure Difference: ≥10 Pa between clean and non-clean zones; ≥5 Pa between different classes; fluctuation ≤±2 Pa.
3. Particle & Microbial Monitoring: 3 consecutive days of dynamic testing. Grade A settle microbes ≤1 CFU/plate.

(3) Process System Acceptance

1. Process Piping: 316L electro-polished tubing; Ra ≤0.5μm; argon-welded and integrity-tested with zero leakage.
2. Equipment Qualification: Key equipment completes DQ, IQ, OQ, PQ to ensure stable performance.

4. Typical Case Analysis

(1) Semiconductor Cleanroom Upgrade

A leading semiconductor fab upgraded for 7nm production with ULPA filters (ISO Class 1) and AMC online monitoring (ppb level). BIM + digital twin optimization reduced energy consumption by 18%. The project passed SEMI certification; chip yield reached 98.5%, annual capacity up 30%.

(2) Biomedical GMP Cleanroom

A pharmaceutical excipient GMP plant used 3-stage filtration (G4/F8/H13) for ISO Class 7 and ozone disinfection. Full-supply full-exhaust airflow maintained 5 Pa pressure gradients. After GMP certification, product yield rose from 95% to 99.2%, orders up 40%.

(3) New Energy Low-Dew-Point Dry Room

A lithium-ion battery dry room achieved -60°C ±2°C dew point using advanced dehumidification (SEMI S2 compliant). Smart EPC integration reduced energy use by 18%. Acceptance rate 98%; granulation yield up 7%, annual cost reduced by 12 million yuan.