VPI Vacuum Coating Technology Application Case Study

VPI Vacuum Coating Technology Application Case Study

(Customized vacuum coating solutions successfully overcome adhesion issues, film oxidation discoloration, and thickness non-uniformity in thick film preparation)

Vision Precision Instruments (VPI), a high-tech enterprise specializing in sample preparation and vacuum coating systems, has been providing high-quality vacuum coating solutions to over 3,000 universities, research institutions, and enterprises globally since its inception in 2004. Noble metal thin films with excellent conductivity and reflectivity have drawn significant attention. However, preparing strongly adhered thick films at micrometer scales faces numerous technical challenges.

VPI Brand and Product Systems: VPI (Vision Precision Instruments), a pioneer in China's vacuum coating industry, offers products including high vacuum magnetron sputtering systems, DC ion sputter coaters, and evaporation coaters, addressing diverse material and application requirements. The SD-900 DC sputtering system and SD-900M magnetron sputtering system are representative products employing direct current sputtering and magnetron technology, respectively. VPI equipment, known for user-friendly operation and stable performance, supports both DC and RF sputtering power sources, enhancing physical vapor deposition (PVD) capability.

Principles of DC and Magnetron Sputtering: Sputter coating utilizes energetic ion bombardment to deposit target atoms onto substrates. DC sputtering is fundamental but faces challenges in efficiency and heat impact. Magnetron sputtering integrates magnetic fields to enhance plasma density, achieving higher sputter rates at lower pressures and temperatures, ideal for heat-sensitive substrates. Each technology has unique advantages and challenges as detailed.

Comparison: Magnetron (VPI SD-900M) vs. DC Sputtering (VPI SD-900)

Application Requirements: A university research team required micrometer-thick noble metal films on special substrates for optical and conductive research, demanding uniform bright-colored films with strong adhesion. Challenges included oxidation-prone targets and high internal stresses in thick films, initially unsuccessfully addressed with the existing VPI SD-900M system.

Initially encountered problems included insufficient adhesion due to low film density, oxidation causing film discoloration, and non-uniform thickness distribution resulting from geometric mismatch between targets and substrates.

VPI engineers collaborated closely with the customer, implementing customized solutions:

• Upgraded Target Size and Power Density: Increasing target diameter from 50 mm to 60 mm improved coverage and deposition rate.

• Rotating Substrate Holder: Replacing the fixed substrate holder with a custom rotating mechanism ensured uniform deposition around the substrate.

• Optimized Process Parameters: Enhanced vacuum pump performance reduced residual oxygen levels, and improved vacuum and gas management minimized oxidation risk.

• Theoretical Modeling and Experimental Validation: Detailed modeling predicted a uniform deposition, subsequently verified through practical experimentation.

Technical Analysis

1. Sputter Energy and Film Density: DC sputtering provided additional ion bombardment energy, ensuring dense film formation and strong adhesion.

2. Deposition Rate and Oxidation Management: Increased sputtering rate prevented oxidation by quickly covering the deposited layers and minimizing exposure time.

3. Target Size Impact on Uniformity: A larger 60 mm target significantly enhanced spatial coverage, ensuring uniform thickness distribution across three-dimensional substrates.

4. Rotational Deposition: Rotating substrate holders effectively transformed spatial unevenness into temporal uniformity, significantly improving film uniformity.

Implementing these solutions led to:

• Significantly enhanced film quality: Uniform bright metallic films with minimal thickness deviation (within ±5%).

• Strong adhesion and stability: Excellent results in cross-cut tape tests and environmental stability.

• Application fulfillment: Achieved optimal optical and electrical properties, satisfying research requirements.

• Customer satisfaction and strengthened cooperation: High appreciation from customers for comprehensive technical solutions and responsive service.

The customized VPI solution effectively addressed complex technical challenges in thick film deposition, reflecting VPI’s profound expertise, systematic engineering approach, and customer-oriented philosophy. VPI continues to set industry benchmarks, providing reliable, customized coating solutions for various advanced material applications globally.