Ultrasonic Coating of Polyimide Insulation Film

Ultrasonic Coating of Polyimide Insulation Film – Cheersonic

In recent years, the application of polyimide coatings in the fields of microelectronics and optoelectronics has been continuously expanding, becoming an indispensable functional material in the manufacturing of various high-end devices. In microelectronics, it is commonly used as an insulating medium between passivation layers, stress buffering layers, and multi-layer metal wiring in integrated circuits and discrete components; In the field of optoelectronics, it is widely used in the orientation layer of liquid crystal displays, the insulation structure of light-emitting devices, and the protective coating of flexible display substrates.

With the iteration of technology, more stringent comprehensive requirements have been put forward for polyimide coatings and their film-forming properties, mainly including:

1. Good coating adaptability: The coating should be able to be evenly applied to different substrates such as silicon, ITO glass, ceramics, etc., with smooth film formation and no obvious defects;
2. Excellent environmental stability: insensitive to humidity and temperature changes, preventing performance fluctuations caused by moisture absorption;
3. High solid and low viscosity characteristics: Maintain low viscosity under the premise of high solid content to meet the requirements of single film thickness and improve process efficiency;
4. Low temperature curing ability: It can complete curing at relatively low temperatures to avoid damage to heat sensitive structures;
5. High transparency: It has good transparency in the ultraviolet to visible light range, reducing light loss in optoelectronic devices;
6. Excellent heat resistance: high glass transition temperature (Tg) and low coefficient of thermal expansion (CTE), ensuring dimensional stability during high-temperature processing;
7. High dielectric performance: including high dielectric strength, high resistivity, low dielectric constant and loss factor, while maintaining low moisture absorption to ensure insulation reliability;
8. Strong interface adhesion: Maintaining good bonding strength with various substrates and matching thermal expansion behavior helps alleviate the risk of delamination caused by thermal stress.

However, there are still significant challenges in comprehensively considering the above performance, mainly due to the constraint relationship between multiple indicators. For example, balancing high solid content and low viscosity is a major challenge, especially in integrated circuit passivation applications that require high coating thickness (such as ≥ 25 μ m).

In this context, ultrasonic coating technology provides a new process path for improving the comprehensive performance of polyimide coatings. This technology efficiently flattens the coating on the substrate surface through high-frequency vibration, significantly improving the uniformity and density of the coating, enhancing interfacial adhesion, and is particularly suitable for the preparation of high-performance high-temperature resistant insulation coatings, providing new technical support for reliable protection of microelectronic and optoelectronic devices.

Compared with traditional scraper coating or spraying, this technology has significant advantages: firstly, the coating thickness uniformity is high (deviation can be controlled within ± 2%), avoiding thermal stress concentration caused by local excessive thickness; Secondly, there is no mechanical shear force in the atomization process, which protects the integrity of the molecular chain structure and enhances the mechanical strength of the membrane (tensile strength can reach 150-200MPa); Thirdly, it has strong droplet penetration ability and can form a pinhole free coating on porous substrates, increasing insulation breakdown strength by more than 30%.

By adjusting the ultrasonic power, coating speed, and solution concentration, polyimide films with a thickness of 5-50 μ m can be prepared, which have excellent high temperature resistance (long-term use temperature up to 260 ℃, short-term temperature resistance above 400 ℃) and a stable dielectric constant of 3.0-3.5. They are suitable for high-temperature insulation scenarios such as new energy vehicle motors and aerospace cables, providing a precise and controllable process path for the preparation of high-end insulation materials.

About Cheersonic

Cheersonic is the leading developer and manufacturer of ultrasonic coating systems for applying precise, thin film coatings to protect, strengthen or smooth surfaces on parts and components for the microelectronics/electronics, alternative energy, medical and industrial markets, including specialized glass applications in construction and automotive.

Our coating solutions are environmentally-friendly, efficient and highly reliable, and enable dramatic reductions in overspray, savings in raw material, water and energy usage and provide improved process repeatability, transfer efficiency, high uniformity and reduced emissions.

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