Cleanrooms in the Semiconductor Industry: "Ultra-clean Guardians" and Core of Technological Innovation in Advanced Processes
I. Core Technical Standards for Semiconductor Cleanrooms: Extremely Stringent Environmental Control Requirements
Semiconductor cleanrooms adhere to the ISO 14644-1 standard. Cleanliness levels increase with process upgrades. Core technical indicators revolve around four dimensions: particle control, temperature and humidity control, airflow organization, and electrostatic and vibration control, ensuring a stable environment throughout the entire manufacturing process.
(I) Cleanliness Levels: From ISO Class 3 to ISO Class 1 – Ultra-Clean Advancement
Different processes correspond to specific cleanliness standards: below 7nm requires ISO Class 3, while 5nm and below requires ISO Class 1-2 – the highest level of ultra-clean environment. To meet the extreme dust control requirements, a four-stage filtration system – pre-filter, medium-efficiency filter, HEPA filter, and ULPA filter – is established. Domestically produced filter media have achieved high-precision import substitution.
(II) Environmental Parameters: High-Precision Temperature, Humidity, and Pressure Control
Semiconductor manufacturing demands stringent precision in temperature and humidity control. Temperature must be stable at 22±0.5℃ (±0.1℃ for advanced processes), and relative humidity at 40%-60%. Cleanrooms must maintain a positive pressure gradient of ≥10Pa, and vibration control in areas such as EUV lithography must be within 0.05μm/s to ensure lithography accuracy.
(III) Airflow Organization: High-Frequency Unidirectional Flow Design
The core area adopts a vertical unidirectional flow design, using fully distributed FFUs for uniform airflow. The air exchange rate in the Class 100 cleanroom is ≥500 times/hour, with an FFU coverage rate of ≥60% and support for zoned speed adjustment to match the airflow requirements of different processes.
II. Core Equipment for Semiconductor Cleanrooms: A Customized Ultra-Clean Protection System
Semiconductor cleanroom equipment is centered on "ultimate dust control, precise regulation, and intelligent operation and maintenance," forming a fully customized system. Equipment performance directly determines operational quality and chip yield.
(I) Air Purification System: Ultra-High Efficiency Filtration and Precise Air Supply
Four-stage progressive filter: The core pollution interception line, ultimately using ULPA ultra-high efficiency filters to achieve ultimate interception of 0.1μm particles. Domestic filter media has achieved import substitution.
Intelligent FFU: Integrates fan and filtration functions, uses a high-efficiency energy-saving motor, supports remote monitoring and fault early warning, significantly reducing unplanned downtime.
Dedicated supply and return air system: Low-resistance ductwork combined with raised floor design, with highly sealed seams to prevent external pollution infiltration.
(II) Environmental Control System: High-precision temperature, humidity, and microenvironment control
High-precision cleanroom air conditioning: Integrates multiple functions, uses PID regulation technology, and is equipped with redundant units to ensure parameter stability.
Large Environment Control System (LMC): Creates a higher cleanliness local environment for critical equipment such as EUV lithography, ensuring the stability of core processes.
Electrostatic and Vibration Control Equipment: Ion fans eliminate static electricity, and high-precision damping equipment controls vibration to meet lithography process requirements.
(III) Personnel/Materials Purification System: Prevents contamination at the source.
Air Shower/Cargo Shower: Essential passage for personnel and materials; high-speed airflow removes dust; double-door interlocking prevents cross-contamination; some models include electrostatic elimination functionality.
Sterile Transfer Window: UV sterilization + air curtain isolation; high-end models integrate particle monitoring to ensure clean material transfer.
Anti-static Cleanroom Equipment: Made of dust-free, anti-static materials; high-cleanliness areas require a complete set of sealed equipment to reduce human-caused contamination at the source.
(IV) Monitoring and Maintenance System: Intelligent management throughout the entire lifecycle.
Full-parameter Monitoring Equipment: Particle counters, temperature and humidity sensors form a comprehensive monitoring network.
AI-powered Early Warning and Control System: An IoT-based LCM system enables pollution risk prediction and automatic adjustment, significantly reducing operation and maintenance costs and downtime risks.
Dedicated Cleaning Equipment: High-frequency cleaning with equipment such as dust-free vacuum cleaners; regular leak checks of filters ensure performance.
III. Core of Semiconductor Cleanroom Operation and Maintenance: Prevention-Focused Full-Process Management
The operation and maintenance of semiconductor cleanrooms adheres to the principles of "prevention first, real-time monitoring, and rapid response." Any oversight may lead to decreased yield or production stoppage. The focus is on resolving issues such as particulate contamination, temperature and humidity fluctuations, and pressure imbalance.
(I) Common Operation and Maintenance Problems and Solutions
Excessive Particulate Contamination: Regularly monitor and replace filters, standardize personnel operations, and optimize cleaning plans for high-frequency areas.
Unstable Temperature and Humidity: Calibrate sensors, optimize adjustment logic, equip with backup units, and strengthen the sealing of the enclosure structure.
Pressure Imbalance: Calibrate sensors, optimize airflow design, restrict personnel access, and promptly replace blocked components.
Equipment Failure Downtime: Develop preventative maintenance plans, stockpile spare parts, and adopt redundant designs to reduce the impact of failures.