Photoresist Coating on SiC Single-Chip Packages

Photoresist Coating on SiC Single-Chip Packages – Cheersonic

With the rapid iteration in high-end fields such as new energy vehicles, photovoltaic energy storage, high-voltage industrial control, and aerospace, third-generation silicon carbide (SiC) semiconductor devices, with their core advantages of high voltage resistance, high temperature resistance, low loss, and excellent high-frequency performance, are gradually replacing traditional silicon-based power devices and becoming the core direction for the upgrading of the power semiconductor industry. SiC single-tubes, as mainstream discrete silicon carbide devices, are characterized by small size, high power density, and good heat dissipation. Their precise structure and stringent packaging processes make them core components of high-end power equipment. Photoresist coating is a crucial process in SiC single-tube packaging, directly determining the device’s patterning accuracy, insulation withstand voltage performance, high-temperature stability, and long-term lifespan. Traditional coating processes are no longer suitable for the high-precision, high-reliability packaging standards of SiC single-tubes. Chifei ultrasonic spray coating machines, with their proprietary precision coating technology, have become the preferred solution for photoresist coating in SiC single-tube packaging.

SiC single-cell transistors differ from traditional silicon-based IGBT single-cell transistors. Their silicon carbide material has unique characteristics, and the packaging process demands higher requirements for coating uniformity, density, and ultra-thinness. Furthermore, the tiny chip size and intricate edge structure make them highly susceptible to coating defects. Currently, mainstream industry processes such as spin coating, air pressure spraying, and manual brushing have significant drawbacks in the mass production packaging of SiC single-cell transistors. Spin coating relies on centrifugal force for shaping, making it difficult to control the thin adhesive layer. This easily leads to problems such as edge buildup and excessively thin centers, resulting in significant waste of photoresist and substandard local insulation performance in the SiC single-cell transistor. High-pressure air pressure spraying has strong impact, easily damaging the delicate surface structure of the SiC chip. Additionally, uneven atomized particle size can cause pinholes, bubbles, and run-off defects in the coating, leading to high-voltage leakage, insufficient temperature resistance, and a significant reduction in product yield. Manual brushing suffers from poor consistency and low efficiency, completely failing to meet the demands of large-scale mass production of third-generation semiconductors.

Addressing the unique process challenges of SiC single-tube packaging, Chifei’s ultrasonic spray coating machine, leveraging its mature high-frequency ultrasonic atomization technology, breaks through the limitations of traditional coating processes, perfectly adapting to the precision photoresist spraying scenarios of SiC single-tube packaging. The equipment uses high-frequency ultrasonic vibration to atomize the photoresist solution into micron-sized, fine, and uniform droplets. Combined with low-pressure, stable airflow guidance, the droplets gently adhere and deposit on the SiC single-tube chip, substrate, and corner recesses. The entire process is free of high-pressure impact, preventing damage to the surface of the silicon carbide precision device and fundamentally avoiding common quality problems such as chip damage, coating pinholes, missing coating, and adhesive buildup.

Chifei’s ultrasonic equipment excels in spraying precision and process adaptability. The equipment can achieve precise control of coating thickness from nanometer to micrometer levels. It can flexibly adjust the atomization frequency, spray flow rate, travel speed, and spray spacing according to the packaging parameters of different SiC single-tube specifications, creating a photoresist coating with uniform thickness, neat edges, and extremely high density, precisely meeting the process standards for fine patterning, insulation protection, and passivation protection of SiC single tubes. For challenging areas like the micro-shaped structures and narrow gaps of SiC single-tube packaging, the equipment achieves full-coverage, dead-angle-free spraying, completely resolving the industry pain point of uneven coating in traditional processes. This effectively improves the device’s withstand voltage, high-temperature resistance, and anti-aging performance.

In terms of mass production and cost control, this equipment boasts strong market adaptability. Traditional processes achieve photoresist utilization rates of less than 30%, while the Chifei ultrasonic spraying machine achieves over 90%, significantly saving on high-end photoresist consumables and effectively reducing enterprise production costs. The equipment is equipped with a fully automated intelligent control system, supporting customized spraying paths and tooling adaptation. It can directly connect to semiconductor automated production lines, enabling continuous batch spraying of SiC single tubes with extremely high consistency and repeatability, eliminating human error, significantly improving production efficiency, and meeting the mass production needs of large, medium, and small silicon carbide packaging companies.

Currently, the third-generation semiconductor industry is developing rapidly, and SiC single tubes are rapidly upgrading towards high-precision, high-reliability, and low-cost mass production, with packaging process precision thresholds continuously increasing. Chifei Ultrasonic has been deeply involved in the semiconductor precision coating field for many years, focusing on optimizing the packaging processes for wide bandgap devices such as silicon carbide and gallium nitride. Its ultrasonic coating machines are fully adaptable to multiple processes including SiC single-tube photoresist coating, insulating coating, and passivation coating. In the future, the brand will continue to iterate its equipment technology and process solutions, providing third-generation semiconductor packaging companies with efficient, stable, and energy-saving one-stop coating solutions, helping to improve the quality and efficiency of domestically produced SiC devices, and empowering the high-quality development of the power semiconductor industry.

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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