High performance metallized PTFE film: coil to coil magnetron sputtering process empowers 5G high-frequency and aerospace applications

1、 Company Overview

Advanced Institute (Shenzhen) Technology Co., Ltd. was established in 2016 and is located in Bao'an District, Shenzhen, Guangdong Province. It is a national high-tech enterprise focusing on shielding materials, insulation materials, thermal conductivity materials, and precious metal coatings. The company has its own registered trademark "Research Platinum" and has dual production bases in Shenzhen and Dongguan. It has passed ISO9001 quality management system certification and its products comply with GJB 773A aerospace standards and RoHS environmental requirements.

In the field of coating technology, the company has independently built magnetron sputtering and vacuum evaporation production lines, using roll to roll continuous production technology, which can continuously deposit metal layers on the surface of flexible polymer films. Suitable substrates include various flexible materials such as FEP, PI, PET, LCP, PPS, PEN, PP, etc., and can be plated with metals including gold, silver, copper, aluminum, tin, nickel, titanium, platinum, etc. Relying on advanced physical vapor deposition (PVD) technology, the company has achieved nanometer level precise control of metal thin films on the substrate surface, with thickness ranging from a few nanometers to several hundred nanometers, ensuring extremely high uniformity and density.

2、 PTFE film: an ideal dielectric material for high-frequency signals

Polytetrafluoroethylene (PTFE) film is one of the core product directions of the company. PTFE has an extremely low dielectric constant and low dielectric loss, making it an irreplaceable insulating substrate for high-frequency signal transmission

• Dielectric constant (10GHz)Stable at around2.1And it hardly fluctuates with frequency from the power frequency to the millimeter wave frequency band (fluctuation range within ± 0.05)
• Dielectric loss (10GHz): Low to0.0001
• Wide temperature range stabilityMaintain stable electrical performance within the range of -200 ℃ to 260 ℃

This "frequency insensitive and temperature insensitive" characteristic makes PTFE irreplaceable in high-frequency and high-speed scenarios such as 5G/6G communication, millimeter wave radar, and satellite payloads.

3、 Technical challenges of PTFE film metallization

The surface energy of PTFE is extremely low (less than 20mN/m), and its chemical inertness is extremely strong. Untreated PTFE film can hardly form effective bonding with any metal. Direct immersion in traditional wet electroplating solution not only fails to deposit metal, but acidic or alkaline liquids can also damage the surface structure of PTFE.

To achieve metallization of PTFE film, surface activation treatment must be carried out first. There are two main technological paths in industry:Sodium naphthalene chemical treatment methodThe effect is significant, but the solution is toxic, difficult to store, and the safety threshold is extremely high;Plasma processing methodSimultaneous physical etching and chemical modification of PTFE surface through plasma bombardment, without the need for toxic chemicals, suitable for mass production, has become the mainstream direction.

4、 Core process: Roll to roll magnetron sputtering coating

Advanced Institute Technology adopts independently developed technology in the field of PTFE and copolymer film metallizationRoll to roll magnetron sputtering processThis has opened up a new technological path that differs from traditional wet electroplating:

• Plasma pretreatment activationUsing nitrogen, argon, or oxygen plasma to bombard the surface of PTFE and introduce polar groups such as - COOH and - OH, the surface energy is increased from less than 20mN/m to over 40mN/m.
• magnetron sputteringOn the surface of the activated film, a metal seed layer is deposited using magnetron sputtering technology, and then thickened to the target thickness using vacuum evaporation or electroplating processes. The stress transition between the metal layer and the substrate is achieved through gradient coating design, effectively avoiding interface delamination caused by modulus differences.
• Enhanced adhesion of coatingTo address the issue of significant differences in thermal expansion coefficients between PTFE and metals, the coating structure design is optimized by introducing a transition layer between PTFE and the functional metal layer, significantly improving the interfacial bonding strength.

This process completely avoids the risk of damage to PTFE structure caused by traditional wet electroplating, with uniform coating and strong adhesion, supporting large-scale supply.

5、 Core product: FEP silver plated film - the "evolutionary form" of PTFE

FEP (perfluoroethylene propylene, also known as F46) is a copolymer of tetrafluoroethylene and hexafluoropropylene, which retains the excellent chemical inertness, low dielectric constant (about 2.1), and wide temperature range stability of PTFE while possessing thermoplastic processing capabilities. FEP can be extruded, stretched, and molded, while PTFE can only be sintered and pressed, which gives FEP a significant advantage in large-scale production.

Advanced Institute of TechnologyFEP silver plated filmUsing FEP (F46) film as the substrate, a high purity silver layer is deposited on the surface through vacuum magnetron sputtering or vacuum evaporation process. This material combines the excellent dielectric properties and chemical corrosion resistance of fluoroplastics with the high reflectivity and conductivity of metallic silver.

Product specification customization scope:

• Film thickness: 0.0125mm to 0.254mm, with conventional thicknesses including 12.5 μ m, 25 μ m, 50 μ m, 125 μ m, and 250 μ m
• Regular width: 1220mm (customizable)
• Silver layer thickness: customized according to optical or conductive requirements
• Optional protective layer: SiO ₂ quartz glass protective layer (thickness 1 to 5 μ m, used for low Earth orbit aerospace applications)
• Optional treatments: antioxidant coating, punching, embossing

Core performance parameters:

• Dielectric constant (1MHz): approximately 2.1
• Volume resistivity: ≥ 10 ¹⁸Ω· cm
• Infrared reflectance (8-14 μ m): ≥ 98%
• Solar absorption ratio: ≤ 0.08
• Infrared emissivity: ≥ 0.80
• α s/ε ratio: ≤ 0.10
• Long term use temperature: -85 ℃ to 200 ℃ (short-term 260 ℃)
• Water absorption rate:<0.01%

In the millimeter wave frequency range of 24GHz to 77GHz, the dielectric constant fluctuation of FEP substrate is only ± 0.02, and the signal loss is extremely low. It is the preferred material for the insulation layer of high-frequency copper-clad laminates in the 5G millimeter wave frequency range.

6、 Core application areas

（1） Passive thermal control of spacecraft

The solar absorption ratio of FEP silver plated film is as low as 0.08, the infrared emissivity is as high as 0.80, and the α s/ε ratio does not exceed 0.10. This parameter combination means that the material hardly absorbs solar radiation heat in the space environment, while efficiently radiating infrared thermal energy outward, achieving zero energy passive temperature control.

This product has been applied in thermal control solutions for extreme temperature difference environments (such as the lunar surface -180 ℃ to 130 ℃). Chang'e-6 and the fifth new generation Beidou navigation satellite both use high-performance thermal control coating materials such as conductive F46 thin film silver plated secondary surface mirrors. In response to the erosion problem of low Earth orbit atomic oxygen on the silver layer, the company provides a SiO ₂ quartz glass protective layer coating solution, effectively extending the service life in orbit.

（2） 5G millimeter wave high-frequency substrate

At the 28GHz frequency band, the measured transmission rate of FEP based high-frequency copper-clad laminates can reach 20Gbps, far exceeding the traditional PI substrate scheme (about 4Gbps). FEP composite films account for approximately 28.5% of the global 5G high-frequency substrates. The product is widely used in the fields of high-frequency copper-clad insulation layer, millimeter wave antenna reflection layer, flexible circuit board substrate, and high-frequency electromagnetic shielding film.

（3） Chemical and semiconductor corrosion-resistant lining

F46 film can withstand a mixture of 49% hydrofluoric acid and 30% nitric acid for over 800 hours without leakage at 65 ℃. The product is widely used in reactor, pipeline, valve lining, strong acid and alkali resistant storage tank protective layer, as well as semiconductor wet cleaning tank lining for processes below 14nm and high-purity chemical transportation pipeline lining.

（4） Military supporting equipment and special cables

The product complies with GJB 773A military standard and is suitable for special cable scenarios such as oil well logging cables, aviation wires, and submersible motor winding wires. It has a temperature resistance range of -65 ℃ to 200 ℃.

7、 Processing characteristics and scale advantages

FEP silver plated film can be thermoplastic processed and supports conventional molding methods such as injection molding, extrusion, and blow molding. Compared to PTFE silver plated film (which requires sintering and pressing and is difficult to process), this product has higher production efficiency and better molding accuracy, making it suitable for large-scale applications. Advanced Institute Technology has adopted a self-developed roll to roll magnetron sputtering process to achieve stable mass production of ultra-thin (≤ 10 μ m) FEP silver plated films.

The company has the ability to supply in bulk, and its products have been widely used in domestic aerospace, 5G communication, chemical and military industries. With the purity of domestically produced F46 resin exceeding 99.99% and the continuous improvement of domestication rate of production equipment, the company is continuously expanding production capacity to assist in the independent controllability of key materials.

8、 Conclusion

From the extremely low dielectric loss of PTFE to the thermoplastic processing advantages of FEP, from plasma activation to roll to roll magnetron sputtering - Advanced Institute (Shenzhen) Technology Co., Ltd. continues to deepen its cultivation in the field of fluoroplastic film metallization, providing high-performance metallization film solutions for high-end manufacturing fields such as 5G high-frequency communication, aerospace thermal control, and chemical corrosion prevention with independent innovative core processes. The company adheres to the whole package service concept of "material technology application solutions" and is committed to promoting the localization process of key materials, helping the high-quality development of China's high-end manufacturing industry.

*The data in this article is sourced from publicly available information and industry reports of the Advanced Institute of Science and Technology, and is for reference only. The product parameters are subject to the actual customized specifications.