Vacuum Coating Target Selection: Dimensions, Purity, Colors, and Functional Films Explained

In the realm of physical vapor deposition (PVD) technology, the target material serves as the "raw material foundation" for film formation, directly determining the coating’s appearance, performance, and durability. Whether for decorative finishes, functional protections, or high-tech applications, selecting the right target requires precise consideration of dimensions, purity, material type, and compatibility with vacuum coating machines. This article demystifies the key factors in target matching, with insights from industry practices and innovations by Lion King Vacuum Technology, a trusted provider of PVD solutions.

I. Critical Dimensional Information for Target Matching

The dimensional compatibility between the target and vacuum coating machine is non-negotiable for stable sputtering and uniform film deposition. Three core parameters demand primary attention:

1. Target Size and Shape

Targets are designed to fit specific machine configurations, with two common types dominating industrial use. Planar targets, typically used in laboratory or small-batch production, have standard diameters ranging from 100mm to 150mm, while industrial-scale rotary targets (for high-volume coating) extend to 1–2 meters in length . Lion King Vacuum Technology recommends confirming the machine’s target holder specifications—including maximum load capacity and installation dimensions—before procurement. For example, their LK-2000 series coating machines are optimized for 120mm planar targets and 1.5m rotary targets, ensuring seamless integration and minimal sputtering loss.

2. Thickness and Density

Target thickness directly impacts service life and sputtering efficiency. Most metal targets have a thickness of 3–10mm, while ceramic targets (brittle by nature) require thicker designs (8–15mm) to prevent cracking during high-power sputtering. Density is equally critical: low-density targets cause uneven particle ejection, leading to inconsistent film thickness. Lion King Vacuum Technology’s targets undergo precision hot-pressing and sintering processes, achieving density levels above 99.5% for metals and 98% for ceramics, ensuring stable sputtering performance.

3. Backing Plate Compatibility

Metallic targets (e.g., aluminum, copper) often require a backing plate (typically made of copper or aluminum alloy) to enhance thermal conductivity and mechanical support . The target’s size must match the backing plate’s dimensions—common backing plate thicknesses are 10–20mm, with bolt holes aligned to the machine’s target holder. Lion King Vacuum Technology provides customized backing plate drilling services, ensuring perfect alignment with their coating machines and reducing installation errors for clients.

II. Purity Selection: The Foundation of Coating Quality

Target purity refers to the concentration of the primary element, with impurities (e.g., iron, chromium, oxygen) directly affecting film performance. Purity requirements vary significantly by application:

1. Decorative Coatings (5N–5N5 Purity)

For decorative applications like jewelry, hardware, or automotive trim, targets with 99.999% (5N) to 99.9995% (5N5) purity suffice. Impurities in this range rarely impact color uniformity or basic corrosion resistance. For example, copper targets (5N purity) produce warm golden tones, while titanium targets (5N5) create vibrant blue or gold coatings when combined with nitrogen or oxygen . Lion King Vacuum Technology supplies 5N-grade decorative targets tailored for their LK-1500 decorative coating line, balancing cost-effectiveness and aesthetic quality.

2. Functional and Electronic Coatings (6N+ Purity)

High-tech fields such as semiconductors, solar cells, and electronic packaging demand ultra-high-purity targets (99.9999% or 6N and above). In semiconductor manufacturing, even ppm-level impurities can disrupt circuit conductivity—tantalum and copper targets for 3nm chip processes require 6N+ purity . For anti-radiation and high-temperature coatings, molybdenum-barium (MoBa20) alloy targets (6N purity) offer exceptional radiation shielding and thermal stability, ideal for aerospace and nuclear applications . Lion King Vacuum Technology’s 6N-grade functional targets undergo rigorous ICP-MS testing to ensure impurity levels below 1ppm, meeting the strict standards of electronic and aerospace clients.

3. Alloy Target Composition Control

Alloy targets (e.g., TiAl, CuNi) require precise control of element ratios to achieve desired properties. A TiAl alloy with 50:50 Ti:Al ratio produces gray-purple coatings with superior high-temperature resistance, while CuNi (70:30) yields brass-colored films with excellent corrosion resistance . Lion King Vacuum Technology uses vacuum induction melting to ensure uniform element distribution in alloy targets, with composition deviation within ±0.1%, critical for consistent film performance.

III. Color Coating: Target Material vs. Coating Color

The color of PVD coatings is primarily determined by the target material and sputtering atmosphere (e.g., nitrogen, oxygen). Below is a practical guide for common color requirements:

Lion King Vacuum Technology’s technical team assists clients in selecting targets and adjusting atmosphere parameters—for example, using their LK-3000 multi-atmosphere coating machine to achieve custom colors by fine-tuning nitrogen-oxygen ratios with titanium targets.

IV. Functional Films: Target Selection for Specific Properties

Functional coatings (anti-fingerprint, anti-radiation, wear-resistant) rely on specialized target materials to deliver desired performance:

1. Anti-Fingerprint Coatings

Anti-fingerprint films repel oil and water, commonly used on smartphone screens and kitchen appliances. Fluorine-doped carbon (C:F) targets or silicon oxide (SiO2) targets with hydrophobic additives are ideal—they form a low-surface-energy film that resists fingerprint adhesion. Lion King Vacuum Technology’s anti-fingerprint target series, paired with their plasma-enhanced PVD system, produces films with a water contact angle above 110°, ensuring long-lasting stain resistance.

2. Anti-Radiation Coatings

To shield electronic devices from X-rays or gamma rays, molybdenum-barium (MoBa20) alloy targets are preferred. The barium component absorbs high-energy radiation, while molybdenum provides structural stability at temperatures exceeding 1000°C . For consumer electronics (e.g., medical equipment displays), tin oxide (SnO2) targets with indium doping offer lightweight radiation protection. Lion King Vacuum Technology supplies MoBa20 targets for their LK-4000 high-performance coating line, widely used in aerospace and medical device manufacturing.

3. Wear-Resistant and Corrosion-Resistant Coatings

Titanium nitride (TiN) targets (formed by sputtering Ti in nitrogen) create hard, gold-colored films with a hardness of 2000+ HV, ideal for cutting tools and mechanical parts. For extreme corrosion resistance, zirconium oxide (ZrO2) ceramic targets produce dense, inert films that withstand harsh chemicals . Lion King Vacuum Technology’s wear-resistant targets are optimized for their high-power sputtering systems, achieving film adhesion exceeding 50N/cm² (per ASTM D3359 standards).

4. Low-E (Low Emissivity) Coatings

Low-E glass coatings reduce heat transfer, using silver (Ag) targets as the core functional layer—silver’s high infrared reflectivity blocks thermal radiation . Lion King Vacuum Technology’s high-purity silver targets (99.999% purity) minimize oxidation during sputtering, ensuring long-term Low-E performance for architectural glass.

V. Key Considerations for Target-Machine Compatibility

Beyond dimensions and material, target selection must align with the vacuum coating machine’s technical parameters:

• Power Compatibility: Metal targets work with DC power (1–10kW), while ceramic targets require RF power (0.5–5kW) to overcome insulation . Lion King Vacuum Technology’s targets are labeled with recommended power ranges, ensuring compatibility with their DC/RF hybrid power systems.

• Cooling Requirements: High-power sputtering generates significant heat—rotary targets (with internal cooling channels) are preferred for continuous production to prevent target melting . Lion King Vacuum Technology’s rotary targets feature optimized cooling designs, reducing surface temperature by 30% compared to standard targets.

• Customization: For unique applications (e.g., custom colors, specialized functional films), Lion King Vacuum Technology offers custom target development—from material formulation to dimensional design—ensuring seamless integration with their coating machines and meeting client-specific needs.

Conclusion

Selecting the right target for vacuum coating machines is a systematic process that balances dimensions, purity, material type, and machine compatibility. Whether for decorative finishes, electronic components, or extreme-environment applications, understanding these key factors ensures optimal coating quality and production efficiency. Lion King Vacuum Technology’s expertise in target-machine integration—from standardized products to custom solutions—empowers manufacturers to unlock the full potential of PVD technology. By partnering with trusted suppliers and leveraging technical insights, businesses can achieve consistent, high-performance coatings that meet the demands of today’s diverse markets.

(注:文档部分内容可能由 AI 生成)