Preventive Maintenance Content and Intervals for Semiconductor Wet-Process Equipment

I. Introduction

Wet-process equipment is widely used in semiconductor manufacturing for processes such as cleaning and etching, involving a variety of chemical solutions and precision control units. The equipment features a complex structure and operates under demanding environmental conditions. Preventive Maintenance (PM) is an important approach to ensuring equipment reliability and extending its service life.

II. Maintenance Cycle Classification and Content

1. Daily Maintenance (Before and After Daily Production)

Daily maintenance is carried out in collaboration between operators and maintenance personnel, focusing on inspecting the equipment’s appearance, basic parameters, and safety devices. It is simple to perform and requires minimal time, with the goal of promptly identifying and eliminating obvious potential faults.

• Visual Inspection: Check the equipment housing, pipelines, and valves for signs of chemical leakage, damage, or loosening; clean out any debris and accumulated liquid inside the equipment.
• Parameter Check: Before startup, verify that key parameters such as temperature, flow rate, and pressure are within the specified ranges; after production ends, confirm that operating data are normal and there are no abnormal alarm records.
• Cleaning Procedures: Remove residual chemical solution from the equipment’s surface, control panel, and liquid spray nozzles; perform a preliminary cleaning of the filter screen to eliminate visible impurities.
• Safety Inspection: Verify that safety devices such as protective doors and emergency stop buttons are functioning properly; check whether the power supply, air source, and chemical solution pipelines are securely connected.

2. Weekly Maintenance (At the End of Each Week)

Weekly maintenance is led by maintenance personnel with cooperation from operators, focusing on thorough inspection and cleaning of wear‑prone components and critical pipelines to prevent minor issues from escalating into major failures.

• Inspection of Wear‑Prone Components: Check seals for signs of aging, deformation, or leakage; replace them immediately if any abnormalities are detected; clean or replace clogged filters.
• Pipeline Maintenance: Inspect the medication lines and air lines for blockages or aging, flush the pipelines with a standard cleaning solution to remove residual medication and impurities, and verify that valve operation is smooth and flexible.
• Precision Component Inspection: Test the sensitivity of temperature and pressure sensors, performing simple calibration when necessary; inspect the atomization performance of the nozzles, and disassemble and clean them if atomization is uneven.

3. Monthly Maintenance (At the end of each month)

Monthly maintenance focuses on the upkeep and calibration of core components, aiming to slow down equipment wear and enhance operational accuracy and stability.

• Core Component Maintenance: Disassemble and clean the pump body, inspect the pump shaft and impeller for wear, and add specialized lubricant; clean scale and residual chemical solution from the heater surface, and check the integrity of the heating tube.
• Precision Calibration: Perform comprehensive calibration of parameters such as temperature, pressure, and flow to ensure the operational accuracy of the equipment; calibrate mechanical transmission components to ensure smooth operation free from abnormal noise.
• Spare Parts Inspection: Check the inventory status of commonly used spare parts (such as seals, filter screens, and nozzles) and replenish them in a timely manner; ensure that all spare parts are free from damage and degradation.

4. Quarterly Maintenance (at the end of every 3 months)

Quarterly maintenance involves systematic inspections, with a primary focus on equipment disassembly and evaluation, as well as electrical system troubleshooting, to identify potential failure points and perform preventive replacements.

• Comprehensive Disassembly and Inspection: Thoroughly disassemble core components such as the pump body, nozzles, and heater to inspect for wear and corrosion, replacing them as necessary; assess the degree of pipeline corrosion and replace severely corroded sections.
• Electrical System Inspection: Check the connection status of electrical wiring and interfaces, identifying potential hazards such as aging or loose connections; clean the inside of the control cabinet to prevent dust from causing short circuits.
• Maintenance Archive Review: Compile maintenance and failure records from the past three months, analyze failure patterns, and optimize subsequent maintenance strategies.

5. Annual Maintenance (At the end of each year)

Annual maintenance is a major overhaul level of equipment maintenance that involves comprehensive inspection and optimization based on the equipment’s service life and condition, laying the foundation for stable operation in the following year.

• Overall Equipment Assessment: Evaluate the degree of aging of core components and develop a replacement plan (for key components such as pump housings and sensors).
• Comprehensive Overhaul: Conduct a thorough overhaul of the electrical system, mechanical system, and chemical solution system, replacing components that are severely aged or worn; perform system calibration to ensure that equipment performance meets design standards.
• Maintenance Plan Optimization: Based on the year‑long records of failures and maintenance activities, optimize the preventive maintenance plan for the following year by adjusting intervals and scope to reduce the failure rate.

III. Conclusion

Preventive maintenance for wet-process equipment should begin with daily inspections and gradually progress to quarterly and annual systematic overhauls. By scientifically defining maintenance intervals and clearly identifying the key priorities for each stage, equipment operational reliability can be effectively enhanced, unplanned downtime risks can be reduced, and the continuity and stability of the semiconductor manufacturing process can be ensured. It is recommended that each manufacturing facility flexibly adjust maintenance content based on the actual equipment types and process characteristics, and continuously optimize its maintenance system.

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