Ultrasonic Spray Coating Machine for Rectifier Diodes

Ultrasonic Spray Coating Machine for Rectifier Diodes – Cheersonic

In the current era of rapid development in power electronics, new energy, home appliances, and communications, rectifier diodes, as core semiconductor devices that convert alternating current to direct current based on the unidirectional conductivity of the PN junction, are hailed as the “one-way valve” of energy conversion and have become fundamental core components of power systems and energy conversion circuits in various electronic devices. Rectifier diodes come in a wide variety, including ordinary silicon rectifier diodes, Schottky diodes, and fast recovery diodes, and are widely used in photovoltaic inverters, automotive OBCs, switching power supplies, home appliance rectification, welding machines, and other scenarios. Their electrical performance, stability, and lifespan directly depend on the high-precision spraying quality of the electrode conductive layer, PN junction passivation layer, and insulating protective layer. Cheersonic ultrasonic spray coating machines, with their core advantages of high precision, low damage, and high adaptability, perfectly meet the precision spraying needs of various rectifier diodes, solving the pain points of traditional spraying processes. They provide core equipment support for the large-scale, high-quality mass production of rectifier diodes, contributing to the upgrading and improvement of my country’s semiconductor device industry.

The core characteristic of rectifier diodes is the energy conversion achieved by utilizing the unidirectional conductivity of the PN junction. Their precise structure and diverse applications place extremely high demands on the coating process. Rectifier diodes are mostly silicon-surface contact type structures with a large junction area, capable of carrying large currents. High-voltage, high-power models are manufactured using high-purity single-crystal silicon. Their core structure includes an anode, a cathode, and the intermediate PN junction. The coating process mainly targets the electrode conductive layer, the PN junction passivation layer, and the insulating protective layer, directly affecting key parameters such as the forward voltage drop, reverse leakage current, and reverse recovery time of the device. The core coating requirements focus on three main aspects: First, high uniformity coating, ensuring a uniform, dense, and gap-free coating thickness to guarantee stable electrode conductivity, avoid abnormal local resistance leading to high forward voltage drop and severe overheating, and simultaneously improve PN junction passivation and reduce reverse leakage current; second, low-damage adaptation, as rectifier diode PN junctions are fragile and electrodes are delicate, requiring low voltage and temperature control throughout the coating process to prevent high-voltage impacts or high temperatures from damaging the PN junction structure and affecting unidirectional conductivity; and third, high compatibility, adapting to different types of rectifier diodes such as Schottky, fast recovery, and ordinary silicon rectifier diodes, and being compatible with the tiny electrode gaps of different device specifications to meet the coating requirements of various application scenarios such as high frequency, high voltage, and high current.

Currently, in the field of rectifier diode coating, traditional coating processes (brush coating, high-pressure gas atomization spraying, and manual coating) have many shortcomings, making it difficult to adapt to their precision structure and the needs of large-scale mass production, becoming a bottleneck restricting the industry’s quality improvement and efficiency enhancement. Brush coating requires highly skilled operators, suffers from poor coating uniformity, and is prone to defects such as missed areas and runs, leading to poor electrode contact in rectifier diodes, increased forward voltage drop, and excessive reverse leakage current, thus affecting energy conversion efficiency. High-pressure gas atomization spraying is prone to uneven droplet size and large coating thickness deviations. High-pressure airflow can easily damage the fragile PN junction structure, introduce micro-dust impurities, and cause a decrease in device insulation performance, even leading to reverse breakdown. Material utilization is only 25%-35%, making it difficult to meet the stringent requirements of high-frequency, high-voltage rectifier diodes. Manual coating is inefficient, produces poor coating consistency, and is prone to introducing contamination, making it unsuitable for large-scale mass production. Furthermore, it is difficult to control coating thickness, resulting in large dispersion of key rectifier diode parameters and increasing the trial-and-error costs of process optimization for enterprises.

Cheersonic ultrasonic spray coating machines, addressing the characteristics, diverse needs, and pain points of traditional spraying methods for rectifier diodes, rely on high-frequency ultrasonic atomization core technology and combine it with key points of rectifier diode manufacturing processes to create customized solutions, completely breaking through the bottlenecks of traditional processes. The equipment converts industrial frequency electricity into a 40-150kHz high-frequency electrical signal using an ultrasonic generator. This signal is then converted into high-frequency mechanical vibration by a piezoelectric ceramic transducer. Utilizing the ultrasonic cavitation effect, conductive, passivation, and insulating slurries are atomized into fine droplets of 0.01-2 microns. This effectively deagglomerates particle clusters in the slurry, precisely controls the solvent evaporation rate, and ensures a uniform, fine, dense, and void-free coating. This perfectly matches the coating requirements of rectifier diode electrodes, PN junction passivation layers, and insulating layers, ensuring stable forward voltage drop, low reverse leakage current, and maintaining the device’s unidirectional conductivity and high-frequency response performance.

The atomization process is conducted under low pressure and temperature control throughout. Droplets are gently deposited on the surface and minute gaps of the rectifier diode, guided only by a small amount of carrier gas. There is no mechanical contact or high-voltage impact, ensuring no damage to the PN junction structure or electrode integrity. Spraying parameters can be flexibly adjusted to adapt to different types of diodes, including Schottky diodes (low forward voltage drop), fast recovery diodes (short reverse recovery time), and ordinary silicon rectifier diodes. It is compatible with various specifications of devices such as 1N4007, FR107, and SiC Schottky diodes, providing seamless coating without dead angles. It integrates seamlessly into automated, large-scale production lines, meeting the mass production needs of new energy, home appliances, and other fields. For the coating needs of rectifier diodes, Cheersonic ultrasonic spraying machines demonstrate four core advantages, helping companies achieve large-scale, high-quality mass production.

First, ultra-precise and uniform coating achieves a coating uniformity of over 99% and a thickness deviation of ≤±1%, effectively avoiding defects such as missed coating and sagging, ensuring good electrode contact for rectifier diodes, and guaranteeing stable forward voltage drop and compliant reverse leakage current, thus solving the pain point of uneven coating in traditional processes.
Second, low-damage protection utilizes low-voltage gentle atomization technology to avoid damage to the PN junction and electrode structure, balancing coating adhesion and device integrity, significantly improving product yield.
Third, high material utilization, reaching over 95%, significantly reduces waste of expensive conductive, passivation, and insulating pastes, lowering the manufacturing cost of rectifier diodes and meeting the economic needs of large-scale industrial production.
Fourth, excellent mass production adaptability supports automated continuous spraying and compatibility with Class 100 cleanrooms, seamlessly integrating into large-scale rectifier diode production lines, adapting to the coating of different types and specifications of devices without dead angles, and solving the problems of low efficiency, high loss, and poor consistency in traditional processes.

Currently, Cheersonic ultrasonic spraying machines are widely used in various rectifier diode spraying scenarios, covering core products such as Schottky, fast recovery, and ordinary silicon rectifier diodes. They are compatible with applications in photovoltaic inverters, automotive OBCs, switching power supplies, welding machines, and home appliances, helping domestic electronics companies solve problems such as device damage, low yield, and material waste caused by traditional spraying processes, achieving breakthroughs in high-quality manufacturing and large-scale mass production of rectifier diodes. As a leading company in the field of ultrasonic electronic equipment, Cheersonic Ultrasonic has been deeply involved in rectifier diode spraying for many years, closely following the trend of device development towards high frequency, high efficiency, and high voltage. Combined with the technological iteration needs of SiC/GaN rectifier diodes, it can provide customized spraying solutions, covering the entire process from equipment selection and process parameter optimization to slurry adaptation.

In the future, Cheersonic Ultrasonic will continue to optimize equipment performance, further improve atomization accuracy and compatibility with various rectifier diodes, helping my country’s rectifier diode industry break through technological bottlenecks and injecting strong momentum into the high-quality development of electronics, new energy, and other fields.

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.

Chinese Website: Cheersonic Provides Professional Coating Solutions