Vacuum Coating Machine Spare Parts and Maintenance Guide

1. Introduction

Vacuum coating machines are critical precision equipment widely used in high-tech fields such as microelectronics, optics, solar energy, and decorative manufacturing. Their performance stability directly determines coating quality, production efficiency, and operational costs. This guide systematically elaborates on key spare parts classification, maintenance procedures, troubleshooting methods, and preventive strategies, aiming to help operators and maintenance personnel achieve standardized equipment management, extend service life, and ensure consistent production quality. Proper maintenance not only prevents sudden failures but also maintains the equipment’s optimal operating state, reducing energy consumption and improving overall productivity .

2. Key Spare Parts Classification and Functions

2.1 Vacuum System Spare Parts

The vacuum system is the core of coating equipment, responsible for creating and maintaining the high-vacuum environment required for film deposition. Critical spare parts include:

• Vacuum Pumps and Components: Mechanical pumps (rotary vane pumps, slide valve pumps) and turbomolecular pumps are essential. Spare parts include pump oil (meeting NAS 6 grade standards), oil filters, bearings, and sealing gaskets. Mechanical pump oil needs regular replacement to ensure pumping efficiency, while turbomolecular pump bearings require specialized grease for lubrication .

• Sealing Elements: Vacuum chamber seals (O-rings, gasket seals) made of high-temperature and corrosion-resistant materials (e.g., fluororubber) prevent air leakage. These are consumable parts that need replacement every 6–12 months .

• Valves and Pipes: Gate valves, angle valves, and vacuum pipelines. Spare parts include valve cores, valve seats, and pipe connectors. Valves control vacuum chamber pressure and gas flow, requiring regular inspection for wear and leakage .

2.2 Coating System Spare Parts

This system is responsible for material evaporation, sputtering, and film deposition, with key spare parts including:

• Deposition Sources: Evaporation crucibles (tungsten, tantalum, or ceramic materials) and sputtering targets (metal, semiconductor, or insulator targets). Crucibles are prone to deformation after high-temperature use, while targets need replacement when their thickness decreases below the minimum working limit .

• Heating Components: Substrate heaters, heating wires, and thermocouples. Heating wires are vulnerable to oxidation and breakage, while thermocouples require calibration annually to ensure temperature measurement accuracy .

• Film Thickness Monitoring Parts: Crystal monitors (quartz oscillators) and probes. These components control film thickness precision; spare probes and calibration standards (standard film thickness sheets) are necessary for quarterly calibration .

2.3 Control and Electrical System Spare Parts

The control system regulates process parameters such as temperature, pressure, and deposition rate:

• Sensors: Pressure sensors, temperature sensors, and gas flow meters. Spare sensors ensure timely replacement when detection accuracy declines. Sensors require regular cleaning to remove dust and residue .

• Electrical Components: Circuit boards, power modules, and relays. These parts control the equipment’s automated operation; spare circuit boards and fuses prevent prolonged downtime due to electrical failures .

• Control Software and Calibration Tools: Backup software copies and parameter calibration tools. Regular software updates and system calibration maintain control precision .

3. Standard Maintenance Procedures

3.1 Daily Maintenance (Post-Production)

• Vacuum Chamber Cleaning: Within 2 hours after coating completion, wipe the chamber inner wall and workpiece holder with lint-free cloth dipped in isopropyl alcohol to remove evaporation residues and sputtered particles. For stubborn deposits, use high-pressure air to blow off loose debris before precision cleaning .

• Sensor Inspection and Cleaning: Use a soft brush to remove dust from pressure and temperature sensors, then wipe with a dry lint-free cloth. Avoid direct contact with sensor probes to prevent damage .

• Basic Parameter Check: Verify vacuum degree (should reach ≤5×10⁻⁴Pa for coating preparation), gas flow stability, and power supply voltage (380V three-phase 50Hz or 220V single-phase 50Hz, with fluctuation ranges of 342–399V or 198–231V) .

3.2 Regular Maintenance (Scheduled Intervals)

• 200-Hour Maintenance: Replace mechanical pump oil, drain old oil completely, and refill with new oil to the specified level (checked via the oil sight glass). Clean the oil filter and check for pipeline leaks .

• 500-Hour Maintenance: Inspect sputtering targets and evaporation crucibles for wear; adjust target-substrate spacing to 50–150mm if necessary. Clean the film thickness monitor probe and verify its position (5–10cm from the substrate) .

• 5,000-Hour Maintenance: Inject specialized grease into turbomolecular pump bearings; replace bearings if rotational resistance exceeds 20% of the initial value. Clean the diffusion pump cavity with gasoline and washing powder solution, then refill with new diffusion pump oil .

• Quarterly Maintenance: Calibrate the crystal monitor with standard film thickness sheets to ensure film thickness deviation ≤±5%. Inspect electrical connections for looseness and clean the control cabinet with dry compressed air .

• Annual Maintenance: Perform argon ion etching on the vacuum chamber (bias voltage -1500V, duration 30 minutes) to restore surface activity after 50 coating cycles. Check the vacuum chamber for welding defects or pinholes using a helium mass spectrometer leak detector .

3.3 Spare Parts Replacement Guidelines

• Sealing Elements: Replace O-rings and gaskets immediately if cracks, aging, or deformation is detected. Ensure correct installation to avoid air leakage .

• Pump Components: When replacing mechanical pump oil, clean the pump cavity to remove residual contaminants. For turbomolecular pump bearing replacement, use manufacturer-recommended parts and follow torque specifications .

• Heating Elements: Replace broken heating wires promptly; reposition thermocouples to the substrate center for accurate temperature measurement .

4. Common Faults and Troubleshooting

4.1 Vacuum Degree Abnormalities

• Symptoms: Failure to reach set vacuum level or sudden pressure drop during operation.

• Causes: Aging seals, loose pipe connections, pump oil contamination, or diffusion pump inefficiency .

• Solutions:

a. Use a helium mass spectrometer leak detector to locate leaks and replace damaged seals or tighten connections.

b. Replace contaminated pump oil and clean the oil filter.

c. For diffusion pumps, disassemble and clean the cavity, then refill with new oil; ensure cooling water flow ≥5L/min .

4.2 Film Quality Issues

• Symptoms: Film peeling, uneven thickness, or pinholes .

• Causes:

◦ Peeling: Substrate contamination, insufficient pre-heating, or excessive film stress.

◦ Uneven thickness: Misaligned deposition source, unstable crucible rotation, or substrate shielding.

◦ Pinholes: Residual moisture/oxygen in the vacuum chamber or impure coating materials.

• Solutions:

a. Strengthen substrate cleaning and perform ion bombardment pre-treatment (bias voltage -1500V).

b. Adjust deposition source position to align with the substrate center and use fixtures to secure substrates .

c. Extend pre-vacuum pumping time to ≤5×10⁻⁴Pa and pre-melt coating materials to remove moisture .

4.3 Electrical and Control System Failures

• Symptoms: Unresponsive operation panel, parameter display abnormalities, or heating system malfunctions .

• Causes: Control board dust accumulation, loose sensor connections, or PID parameter misconfiguration.

• Solutions:

a. Clean the control cabinet with dry compressed air and recheck wiring connections.

b. Recalibrate temperature sensors and adjust PID parameters for stable heating.

c. Restart the system or reinstall control software if program crashes occur .

5. Preventive Maintenance and Management Strategies

5.1 Establish Standardized Maintenance Records

Document all maintenance activities, including spare parts replacement dates, parameter adjustments, and fault handling processes. Track key indicators such as coating cycles, vacuum curve data, and film thickness measurements to form a complete equipment health 档案 .

5.2 Implement Regular Performance Audits

Conduct monthly process analysis meetings to evaluate key coating indicators (adhesion, hardness) using CPK analysis. Initiate process optimization if CPK values drop below 1.33 . Perform quarterly comprehensive equipment inspections covering vacuum performance, electrical safety, and mechanical wear.

5.3 Spare Parts Inventory Management

Maintain a reasonable inventory of critical spare parts (seals, pump oil, heating wires, sensors) based on equipment usage frequency and manufacturer recommendations. Store spare parts in dry, dust-free environments to avoid contamination .

5.4 Train Maintenance Personnel

Ensure operators and maintenance staff are familiar with equipment working principles, maintenance procedures, and safety protocols. Provide training on troubleshooting skills and proper use of tools (e.g., helium mass spectrometer leak detectors) .

6. Safety Precautions

• Before maintenance, shut down the equipment, cut off power, and wait for the vacuum chamber to cool to room temperature. Release vacuum pressure gradually using nitrogen to avoid pressure shocks .

• Use protective gear (gloves, goggles) when handling chemicals such as isopropyl alcohol, caustic soda solutions, or pump oil to prevent skin and eye irritation .

• Disconnect battery cables before servicing electrical components to avoid short circuits . Follow manufacturer guidelines for spare parts replacement to ensure compatibility and safety.