In response to the escalating complexity of electronic applications and the continuous advancements in manufacturing technology, a diverse range of materials are now employed in substrate manufacturing. It is imperative for engineers to judiciously select these materials based on the specific requirements of each application. In addition to the commonly used FR4 material, there exist a multitude of alternatives such as Rogers, PTFE, Taconic, metal substrates, and ceramic substrates, among others.
Ceramic PCB, characterized by their utilization of ceramics as substrate materials, represent a specialized category tailored to excel in diverse high-temperature and high-frequency applications. This unique PCB offer enhanced performance and resilience in demanding operating conditions. In this edition of TechSparks, let us delve deeper into ceramic PCB material and explore their exceptional capabilities.
The Importance of Ceramic PCB
Characteristics of ceramic PCB board
- Compactness: While achieving multi-layer configurations in ceramic circuit boards presents inherent challenges, it is nonetheless feasible to accomplish this task using advanced substrate materials such as Rogers RO4000® series. These high-quality materials enable enhanced component mounting density, allowing for the integration of a larger number of components within a smaller spatial footprint. This capability significantly contributes to achieving higher levels of compactness in ceramic PCB designs.
- Fragility: Similar to ceramic products encountered in everyday life, ceramic substrates used in electronic applications also possess a delicate nature. Hence, special caution must be exercised when utilizing them. Among the diverse range of ceramic printed circuits, Si3N4 ceramic PCB exhibits exceptional solidity and reliability. While they may be susceptible to cracking or damage under intense mechanical shock or excessive bending, they remain one of the most favorable options for electronic applications demanding high thermal conductivity, elevated temperature resistance, and chemical stability. It excel in enduring harsh environmental conditions, ensuring the preservation of electrical performance over prolonged operational periods.
- Compatibility: The high compatibility of it needs to be contingent upon meticulous considerations of circuit design, material selection, component integration, and manufacturing processes, aligning them with the specific requirements of the intended application. Compatibility manifests in several key aspects, including temperature compatibility, chemical compatibility, size compatibility, as well as compatibility with discrete, integrated, and resistive electronic components, enabling seamless integration across a broad spectrum of applications. Thorough assessment and validation of these factors are crucial to ensure optimal compatibility and performance of ceramic PCBs in their intended operational environments.
- Expensive: Compared to traditional PCB materials like FR4, ceramic substrate PCB is more expensive. This cost disparity arises from factors such as increased manufacturing complexity, higher failure rates, and elevated material costs. When choosing the type of circuit board for your project, it is imperative to thoroughly evaluate the genuine necessity and explore potential alternatives. TechSparks strongly advises the utilization of ceramic substrates primarily in high-end electronic applications, as opposed to low-margin projects such as consumer electronics.
Wide range of application fields
- Telecommunications: Ceramic core PCB has gained immense popularity within the telecommunications industry, primarily due to their exceptional support for high-frequency and high-speed signal transmission. For instance, in wireless communication systems, it is a vital component in base stations, antenna systems, and radio frequency modules, guaranteeing reliable signal performance. In microwave equipment, contribute to enhanced functionality by providing lower dielectric constants, thereby enabling superior performance in transmitter, receivers, MIC, and microwave link. Moreover, in optical communication systems, ceramic multilayer PCB plays a pivotal role in modules, optical switches, optical routers, optical amplifiers, and other related components, facilitating efficient optical signal transmission through fiber optic networks.
- Medical Applications: The growing demand for telemedicine, implantable medical electronics, and home medical electronic devices has led to the essential adoption of ceramic printed circuit board in the medical field. Ceramic circuits offer indispensable advantages in terms of stable signal transmission and high-speed remote medical operations, enabling healthcare professionals to perform real-time and precise remote procedures. In specific medical devices such as cardiac pacemakers and brain pacemakers, ceramics are utilized for their corrosion resistance properties. Furthermore, Contribute to the improvement of functionality and performance in home medical devices such as oximeters, glucose monitor, breathalyzers, and more.
- Research and Development: These circuit boards offer exceptional performance characteristics, including robust thermal conductivity, reliable signal integrity, and prolonged operational lifespan. These attributes enable advanced electronic circuit design and thorough evaluation of prototypes, ensuring accurate assessment and optimization of device performance. Ceramic circuit boards serve as indispensable tools in the pursuit of cutting-edge technological advancements in various fields of research and development.
- Expanded Applications: As an essential component in electronic manufacturing, the application of PCB, and ceramic substrate, as a high-end plate, appears more frequently in the high-end field. Besides the aforementioned applications, they find extensive utilization in aerospace, military, and industrial manufacturing sectors.
Types of Ceramic Printed Circuit Boards
Among printed circuit board substrate materials, aluminum and alumina are often confused. When we refer to Al2O3 PCB, we are actually referring to alumina ceramic PCB, which happens to be the most extensively used ceramic substrate. Typically, the alumina content in these PCBs exceeds 90%. However, it is worth noting that the actual content can vary depending on the manufacturer’s capabilities and specific application requirements. It is possible to achieve alumina content of 96%, 98%, or even 99% in certain cases. Higher alumina content directly correlates to improved thermal conductivity and insulation properties.
Aluminum Nitride (AlN) is a highly advantageous material in the realm of high-temperature and high-current circuits, owing to its exceptional properties such as superior thermal conductivity (170 W/mK), high dielectric strength, and low thermal expansion coefficient (CTE <4 ppm/°C). These characteristics make it a superb choice for applications in memory modules, multilayer interconnection boards, and transmit/receive modules. When fabricating aluminum nitride ceramic PCB, hole metallization can be achieved using silver (Ag) or copper (Cu).
Silicon nitride (Si3N4) is a substrate material renowned for its exceptional reliability, robustness, low friction coefficient, and self-lubricating properties. These desirable characteristics stem from its covalent bonding nature, where interatomic bonds predominantly consist of covalent bonds. Through extensive utilization and empirical evidence, silicon nitride ceramic PCB has emerged as an excellent solution for applications in the automotive industry and deep-sea exploration. They exhibit remarkable capability in withstanding diverse challenges such as high pressures, elevated temperatures, and densely packed circuits.
Multilayer Ceramic PCB
Multilayer PCB is constructed by stacking multiple layers of ceramic material, creating a robust and compact structure. The individual layers are securely bonded together using an adhesive, and the board’s surface is then coated with copper, forming conductive pathways. It is important to note that the complexity of manufacturing escalates with each additional layer incorporated into the PCB design. Pure ceramic cores, due to their inherent fragility, are typically limited to single-layer configurations and even achieving a double-layer structure poses significant challenges. In practice, the circuit board terminology “Multilayer ceramic PCB“ commonly refers to the utilization of Rogers material.
Rogers Ceramic PCB
Rogers Corporation is a renowned manufacturer and research and development (R&D) entity specializing in high-quality laminates for the electronics industry. Among their extensive product range, the RO4000® series stands out as a notable offering. The laminates within this series are utilized in the production of Rogers ceramic PCB. Noteworthy laminates in this series encompass RO4000® LoPro®, RO4003C™, RO4350B™, and RO4360G2™, among others. To access the most authoritative and up-to-date parameters, it is recommended to visit Rogers Corporation’s official website.
Thick Film Ceramic PCB
Thick film technology is a widely utilized manufacturing method in the electronics industry. In contrast to traditional circuit boards where the conductive layer is composed of platinum, silver, or gold with a thickness in the range of a few microns, thick film technology involves a range of tens to hundreds of microns. Within this range, the surface of the thick film ceramic substrate facilitates the integration of capacitors, resistors, and integrated circuits.
The primary purpose of utilizing a ceramic core PCB is to cater to high-frequency circuits. By incorporating thick film technology, the ceramic board becomes capable of accommodating higher currents and power levels. This is achieved by applying specialized ink onto the ceramic substrate, followed by a curing process through firing. Such PCBs are often referred to as thick film resistor ceramic boards, as they feature a layer of dependable carbon resistor printing for enhanced performance and reliability.
LTCC, short for Low Temperature Co-fired Ceramic, represents an emerging micro-assembly technology that seamlessly integrates the benefits of a thick-film process with high-temperature co-firing. This innovative technique involves firing a single layer of ceramic substrate at temperatures ranging from 850 to 900°C, followed by the drilling of holes to create vias. Subsequently, the vias are screen printed with conductive, dielectric, and resistive pastes, enabling the formation of circuit elements. The Low-Temperature Co-fired Ceramic PCB ensures optimal interconnectivity and compatibility between various circuit elements, resulting in compact and high-performance electronic assemblies.
HTCC, which stands for High Temperature Co-fired Ceramics, is an advanced manufacturing technology. It distinguishes itself from LTCC by undergoing a firing process at a higher temperature of 1600°C. The resulting ceramic board manufactured using this technology is referred to as High-Temperature Co-fired Ceramic PCB. These PCBs offer exceptional suitability for demanding electronic applications, particularly in harsh environments. Their utilization is highly beneficial in the design of microelectronics and optoelectronics packages, providing robustness and reliability.
Using Ceramic Base PCB for Projects
Ceramic circuit design guide
- Layer Stack: Determining the appropriate number and configuration of ceramic layers, signal and power planes is crucial to achieve the desired electrical and thermal performance. During the design process, careful consideration is given to separating the signal layer from the power layer. Moreover, achieving a balanced distribution of the signal and ground layers is essential. Building a low-impedance power loop necessitates the effective utilization of the power and ground layers.
- Circuit Layout: Optimal board performance hinges on strategic component placement and routing techniques that prioritize signal integrity and mitigate signal interference. To enhance the circuit’s overall performance, conceptual wiring connections are maintained, and interlayer connections are made using through-hole or blind-hole. All wiring is executed in compliance with industry standards such as IPC.
- Heat Dissipation Design: Although ceramic printed circuit boards exhibit excellent heat dissipation properties compared to other substrate materials, it is imperative to implement meticulous heat dissipation designs. This includes incorporating heat-conducting copper traces, employing through holes, incorporating heat sinks, and conducting thermal simulations and emulation experiments during the circuit design phase to assess the board’s thermal performance under actual operating conditions.
- Mechanical Strength: Given the relatively fragile nature of ceramic materials, careful consideration is required when selecting materials for projects that demand robustness. Additionally, increasing the substrate’s thickness in a judicious manner serves as a primary strategy to enhance mechanical strength. Reinforcement techniques such as incorporating ceramic powder or fiber reinforcements can also be employed in areas that require additional reinforcement.
Ceramic circuit board manufacturing
- Ceramic Green Sheet Preparation: The production of ceramic green sheets involves meticulous preparation of finely powdered ceramic material blended with binders, which is then precisely cut to the required dimensions.
- Screen Printing: Conductive and insulating pastes are meticulously screen-printed onto the ceramic board to create intricate patterns of conductive traces, vias, and insulating layers.
- Layer Stacking and Pressing: Ceramic PCB inner layers featuring alternating conducting and insulating layers are meticulously stacked on top of one another. Subsequently, the stack is firmly pressed together to ensure optimal adhesion.
- Lamination and Debinding: To achieve a cohesive ceramic structure, the stacked layers undergo a lamination process that subjects them to both heat and pressure. During this process, binders are removed through a debinding procedure.
- Firing and Sintering: The laminated structure undergoes a high-temperature firing process in a specialized furnace, promoting sintering. This vital step enables the ceramic particles to fuse together, resulting in the formation of a dense and robust structure.
- Metallization and Plating: Metal deposition and plating techniques are employed to create solder pads, component contacts, and vias, facilitating electrical connections within the circuitry.
- Surface Finishing: To safeguard exposed copper traces and ensure optimal solderability, the multilayer ceramic boards undergo meticulous surface finishing procedures, such as OSP, HASL, and ENIG.
Screen Reliable Ceramic PCB Manufacturers
We have placed great emphasis on the challenges and costs associated with manufacturing ceramic circuit boards. Therefore, when selecting suppliers for your project, it is crucial to consider their capabilities and services to ensure smooth project execution. TechSparks is here to provide guidance on selecting ceramic PCB manufacturers:
- Specialization: Within the technology industry, there are manufacturers who specialize in ceramic PCB manufacturing. These manufacturers possess superior expertise and capabilities in this specific area. Notable examples include CERcuits, Kyocera Corporation, and Sunlord Electronics Co., Ltd.
- Online Quotation: During the initial stage of the project, engineers often require prototype boards to verify the performance of their PCB designs. For ceramic PCB prototypes, TechSparks strongly recommends choosing manufacturers that offer online quotation services. These manufacturers not only provide competitive pricing but also offer turnkey solutions, encompassing the entire project from manufacturing to assembly. Prominent examples include Rush PCB, Seeed Studio, Bay Area Circuits, and PCB Universe.
- Service Providers: The ceramic PCB industry is still evolving, and there is a growing demand for comprehensive service providers. In larger-scale projects, comprehensive services play a crucial role in ensuring smooth project execution. Without detailed support from the supplier, project management can become cumbersome. For this reason, partnering with service providers who can assist with various aspects of your project is highly recommended. Noteworthy service providers in this field include FS Technology, Morgan Advanced Materials, and Remtec Inc.
In the future of electronic development, the application of ceramic PCB will continue to expand, necessitating the advancement of various technologies to further propel their development.
- 3D printing: This technology proves highly advantageous when dealing with boards featuring intricate features and complex geometric shapes. Leveraging 3D printing enables the fabrication of ceramic PCB with intricate shapes and structures.
- Direct Copper Printing: By utilizing a printing method to deposit copper onto the surface of a ceramic substrate, project costs can be reduced compared to traditional electroplating processes.
- High-speed drilling: This advancement accelerates project timelines by meeting the demand for precise hole placement in PCB.
- In-line testing: Employing this reliable monitoring method allows for the early detection of potential issues prior to the assembly. Consequently, it enhances overall quality and cost-effectiveness.
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