Thick-film ceramic PCB is a specific type of ceramic PCB that involves the deposition of slurry directly onto the substrate using micro-flow direct writing technologies such as screen printing, micro-pen direct writing, and inkjet printing. These technologies allow for the creation of conductive lines and electrodes, which are then formed through high-temperature sintering. This method is compatible with most ceramic substrates. During the high-temperature firing process, a film with strong adhesion is formed on the ceramic circuit board. Through repeated iterations, a multilayer interconnection structure, including resistance or capacitance circuits, is developed, earning it the name “thick film resistor ceramic PCB.” This innovative technology expands the possibilities for ceramic substrates, and in this article, we will delve into the details of this printed circuit board with TechSparks.
Features of Thick Film Ceramic Substrate
- Thick-film ceramic PCB exhibits robust mechanical stress resistance, ensuring shape stability. It possesses high strength, thermal conductivity, and insulation properties. Furthermore, it demonstrates exceptional binding strength and corrosion resistance.
- It demonstrates excellent thermal cycle performance, capable of enduring up to 50,000 cycles, thereby ensuring high reliability.
- Similar to a PCB board or an IMS substrate, it allows for the etching of diverse pattern structures without any pollution concerns.
- The operational temperature range spans from -55°C to 850°C, while its coefficient of thermal expansion closely matches that of silicon. This characteristic simplifies the production process of power modules.
- The thick film technology involves employing a screen printing process to apply a conductor layer (composed of copper or silver) onto a ceramic substrate.
- It is particularly suitable for utilization with aluminum 2O3/AlN and sapphire substrates.
- This approach provides a cost-effective solution that requires fewer manufacturing processes in comparison to alternative methods.
- The conductor thickness ranges from 7-20um, rendering it unsuitable for power electronic equipment that demands high current capacity.
- Due to the nature of the conductor application, it is also ill-suited for designs necessitating fine tracks and/or plated/filled vias.
Why Thick Film Technology is Important in Ceramic PCBs
Ceramic PCB is utilized extensively in high-end electronics as a premium circuit board type. However, traditional substrates may not adequately address certain requirements, necessitating the implementation of a thick film process to enhance the board’s thermal conductivity, temperature stability, and structural flexibility. Consider the following examples:
- Military: The utilization of thick film ceramic PCB in the production of military electronics is an essential measure aimed at reducing costs. Compared to traditional ceramic substrates, thick-film ceramic boards employ polymer materials, simplifying the manufacturing process and yielding a lower rework rate. Consequently, they offer increased cost competitiveness.
- Medical: In applications such as telemedicine, where higher electrical signal transmission requirements exist, circuits carry significant currents that can lead to overheating and damage. By incorporating thick film technology, the ceramic substrate’s thermal conductivity is enhanced through the addition of a conductor layer (such as copper or silver), thereby reducing the likelihood of such failures.
- Industrial control: PCB boards used in industrial control applications often operate in extreme environments, necessitating flexible PCB design and manufacturing to meet these demands. Ceramic PCB is notoriously challenging to process and manufacture. However, the implementation of thick film technology enables the creation of intricate structures and circuits on ceramic substrates through the layering of different materials or mask printing.
- Power Electronics: Power electronic devices, including converters, inverters, and power modules, require the handling of high-power currents, imposing stringent demands on thermal conductivity and electrical insulation. Increasing the film thickness of the ceramic PCB enables the attainment of these requirements. The augmented film thickness results in a more substantial insulating layer and improved dielectric strength on the PCB surface, mitigating common PCB problems, such as signal interference, leakage, or breakdown.
Thick-film ceramic PCBs will undoubtedly exhibit compelling development prospects and advantages in future electronic applications. With their enhanced thermal conductivity and superior electrical insulation properties, they contribute to the creation of highly reliable and stable circuits. However, it is important to note that further optimization and advancement of this technology are necessary to fully unleash its potential.