In order to realize the interconnection between chip and electronic component in the use of high power electronic devices, the surface of ceramics, as a substrate material, needs to be metallized. Ceramic metallization has the following requirements: good sealing, low resistance and resistivity of metal conductive layer, and strong adhesion with ceramic substrate, ceramic metallization still need to have high thermal conductivity. Therefore, Cu, which has good ductility, thermal conductivity and electrical conductivity, has become the most commonly used material in power electronic devices.
For more information, please visit our website.
Fig. 1 schematic diagram of ceramic substrate copper clad
Although ceramics have more excellent integrated properties than the other two kinds of packaging substrates, as ceramic materials are strong covalent bond compounds, their electronic coordination is very stable, and it is not easy to react with other materials, and wettability difficulty with common metals, and the performance of metallized ceramic substrate is closely related to the stability of power electronic devices in operation, so it is the reason that restricts the wide application of ceramic packaging substrate, therefore, it is significant to explore the metallization of ceramic surface. At present, the common methods of metallization of ceramics mainly include electroless plating metallization, direct copper-clad metallization, thick film metallization, thin film metallization and so on. The following are some kinds of ceramic packaging metallization process.
1&#;Electroless plating metallization
Electroless plating metallization is a method by which metal ions are reduced to metal by a chemical reaction with a reducing agent and deposited on the surface of a substrate material. The core is the formation of a metal layer through a controlled redox, fig. 1.1 is a schematic diagram of electroless plating process. Electroless copper plating reduces CU 2+ to Cu and deposits it on the substrate with catalytic activity:
Step1: Cu 2+ is reduced to Cu atoms at the cathode, as shown in Formula 1-1;
Step 2: Formaldehyde provides the electrons required for the reaction at the anode, as shown in Formula 1-2;
Step 3: The redox equation of electroless copper plating, as shown in Equation 1-3.
Figure 1.1 Schematic diagram of the electroless copper plating process
2&#;Direct copper metallization
Direct copper-clad metallization refers to using Cu's xygen-containing eutectic liquid to directly coat the Cu foil in a high-temperature, weak-oxygen atmosphere.
Ceramic surface method, mainly used for Al 2 O 3 and AlN ceramic surfaces. The principle is that Cu 2 O and CuO generated by the reaction of Cu and O can react with Al in the substrate within the temperature range of - &#; to generate spinel substances of CuAlO 2 and CuAl 2 O 4, which promotes the formation of higher spinel materials between ceramics and Cu. The bonding strength of the AlN ceramic substrate is directly clad with copper and metallized. The AlN needs to be oxidized first to form Al 2 O 3 on its surface. Figure 2.1 is a schematic diagram of the process of direct copper clad metallization of AlN. The reaction formula is as follows:
Figure 2.1 Schematic diagram of AlN direct copper coating metallization process
3&#;Thick film metallization
Thick film metallization is a technology in which metal slurry is coated on the ceramic surface through screen printing, and then subjected to high-temperature drying and heat treatment to form a metallized ceramic substrate. Figure 3.1 is a schematic diagram of the screen printing process. The slurry is mainly composed of functional phase, binder, and organic carrier. The functional phase is the main body of the thick film slurry, which is formed by coating metal powder on the ceramic surface and then undergoing a heat treatment process. Metal film layer; the binder is a glass phase or oxide that is sintered at high temperature to improve the adhesion between the metal film layer and the ceramic substrate; the organic carrier is used to increase the surface activity of the organic slurry, making the slurry more uniform. organic solvents or surfactants.
Figure 3.1 Schematic diagram of screen printing process
4&#;Thin film metallization
Thin film metallization is a process that uses physical methods to ionize the surface of solid materials into ions under high vacuum conditions, and then deposits the required thin film on the surface of the ceramic substrate through low-pressure gas, that is, physical vapor deposition technology (Physical Vapor Deposition, PVD), mainly Including magnetron sputtering coating, ion plating, arc plating, etc. Figure 4.1 is a schematic diagram of magnetron sputtering coating. The core is that Ar 2+ is accelerated by an electric field and then bombards the target electrode made of the material to be sputtered. When the ion energy is appropriate, Ar 2+ will burn the target surface The atoms are sputtered out and then shot towards the substrate in a certain direction, thereby achieving the deposition of a thin film.
Figure 4.1 Schematic diagram of magnetron sputtering principle
The above-mentioned metallization methods of ceramic substrates each have their own advantages and disadvantages. Electroless metallization has high production efficiency and can achieve mass production. However, the bonding force between the metal layer and the ceramic substrate is limited and cannot meet many specific requirements. Application scenarios. Direct copper-clad metallization, also known as high-temperature sintering, is a relatively common production process that not only meets production efficiency, but also has a certain bonding strength between the metal layer and the ceramic substrate. However, because it uses high-temperature sintering, The metallization coating carried out, therefore, limits the application of many low melting point metals. Thick film metallization, also known as screen printing, is simple and operable to produce. However, it cannot achieve good control over the precision of metallization thickness and line width and spacing, and cannot produce high-precision precision circuits. Thin film metallization, also known as magnetron sputtering, uses the principle of van der Waals force to make the metal layer and ceramic substrate have a strong bonding force. However, the production efficiency is low, and at the same time, only a very thin metal layer can be formed. Usually At the nanometer level.
Folysky Technology Company&#;&#;
Folysky Technology Company effectively uses a combination of several metallization processes. In the production process, first, a 50-300nm metal seed layer (titanium) is formed on the surface of the ceramic substrate through a magnetron sputtering process (thin film metallization). layer 50-100nm, copper layer 100-300nm), the metal seed layer and the ceramic substrate are bonded through van der Waals forces, and then, the metal thickness is increased on the metal seed layer through electroplating (electroless plating). In this way, it is better than simply The circuit performance of ceramic substrates produced by magnetron sputtering or electroless plating is much better. On the one hand, it can effectively strengthen the bonding strength between the metal layer and the ceramic substrate. On the other hand, it can also achieve different layer thicknesses (thickness 1- μm) metallization production.
The Role of Ceramic Metallization in Modern Aerospace and Medical Applications
Ceramic metallization has become a powerful driver of advanced solutions for the high-tech aerospace and medical industries, providing materials that can withstand extreme conditions while maintaining superior performance.
Marrying the superior properties of ceramics with the electrical and thermal conductivity of metals, this innovative process allows for the development of advanced components. These components are durable, resistant to extreme conditions and capable of performing complex functions essential for modern technology, making them ideal for a range of critical aerospace and medical applications.
Leaders in precision ceramic and sapphire components for military, medical, and aerospace applications, Elcon Precision has built a reputation for delivering higher-quality components and shorter lead times. With over five decades of industry experience, the Elcon team offers a full turn-key solution, from sourcing materials and engineering/design support to machining tooling and prototype testing.
This article breaks down the fundamentals of ceramic metallization and its key applications, advantages, challenges, and limitations.
Ceramic metallization is a process in which a layer of metal is deposited onto the substrate's ceramic surface to provide a wettable surface for subsequent brazing.
The process typically includes cleaning and preparing the ceramic surface, applying a layer of our metallization paint (molybdenum/manganese or molybdenum/manganese/tungsten blend) through needle painting, brush, spray, or screen-printing, and then sintering the coated ceramic to bond the metal layer permanently. The result is a component ready to be brazed into a hermetic assembly.
Unique Properties of Metallized Ceramics
Thermal Resistance: Ceramics can withstand extremely high temperatures, making them ideal for high-temperature applications in aerospace and medical fields.
Electrical Insulation: Ceramics provide excellent electrical insulation, essential for components that need to isolate electrical signals.
Chemical Stability: The inert nature of ceramics ensures they remain stable and do not react adversely in harsh chemical environments.
Enhanced Bond Strength and Robustness: This unique metallization formulation developed and produced entirely in-house enables a hermetic ceramic to metal bond in a brazed assembly.
At Elcon, our proven ceramic metallization process uses proprietary thick-film molybdenum/manganese and molybdenum/manganese/tungsten paints as the base layer on a ceramic substrate. Our expert team developed unique molybdenum-manganese (Mo-Mn) and tungsten(W) based metallization paints that enable a hermetic ceramic-to-metal bond in a brazed assembly.
For more information, please visit Zmdy Ceramics.
To prevent oxidation and improve wettability after the metallization paint is sintered into the ceramic at high temperature, it is plated using either electroless or electrolytic plating or nickel oxide paint. Metallization and nickel thickness is measured using XRF technology to ensure desired thickness specifications are met.
We also offer plating on top of the Mo-Mn and Mo-Mn-W paints with the choice between silver and nickel (both with excellent electrical conductivity) and the highly corrosion-resistant and biocompatible gold.
Due to its ability to combine ceramics' high thermal stability and electrical insulation with metals' enhanced electrical conductivity and structural integrity, ceramic metallization has become an essential process for critical aerospace applications.
The innovative process ensures that critical aerospace components can perform reliably under extreme conditions, including high temperatures, pressures, and corrosive environments.
High Voltage, High Vacuum, and High-Pressure Environments
Ceramic metallization is crucial in the aerospace industry, particularly in high-voltage, high-vacuum, and high-pressure environments. Metalized ceramics are essential in jet engines and missile components, where they withstand extreme conditions while ensuring reliability and performance.
Electrical and Thermal Conductivity
Metallization significantly improves aerospace electronics by enhancing the electrical and thermal conductivity of ceramics, enabling efficient heat dissipation and stable electrical connections. Metalized ceramics in PCBs provide excellent electrical insulation and superior thermal conductivity, ensuring efficient heat management and reliable operation under extreme conditions. For capacitors, the metal layer improves electrical conductivity, allowing for better charge storage and discharge rates, which is crucial for the precise and high-speed demands of aerospace systems. The same applies to inductors, where metallization enhances the magnetic properties and overall efficiency of the component.
Corrosion Resistance
By providing increased corrosion resistance, metallization ensures long-term durability and reduces maintenance requirements for components exposed to harsh aerospace environments.
Ceramic metallization is critical for the development of high-performance electronic components that ensure the reliability and safety of medical devices.
In an industry where accuracy can directly impact patient outcomes, metalized ceramics provide the necessary precision and stability, especially in high vacuum and pressure applications, such as diagnostic imaging equipment and advanced surgical instruments. The robustness and consistent performance of these components are crucial in maintaining the functionality and safety of sophisticated medical electronics.
Medical device components often utilize gold plating for its biocompatibility and corrosion resistance, ensuring safe and durable performance in devices such as pacemakers, defibrillators, and implantable sensors. This metallization technique enhances the reliability and longevity of these life-saving devices.
The Key Industry Challenges Faced
As ceramic metallization becomes more popular, those searching for a trusted partner face numerous challenges.
Long lead times with ceramic metallization can delay the production and deployment of critical components in aerospace and medical applications. Poor quality metallization is another key issue with certain manufacturers, which can result in unreliable performance and premature failure of components, undermining the overall efficacy and safety of high-stakes technologies. Our XRF x-rays allow us to measure the metallization thickness, guaranteeing that customers receive parts with the correct specification.
The team at Elcon delivers precise solutions to these challenges, positioning them as a trusted partner for ceramic metallization in the aerospace and medical sectors. Collaborating with an array of approved ceramic vendors, we shorten the lead times for machining and offer better metallization lead times. We also offer blanket orders for customers with a time-sensitive demand for long-lead items.
Performance and reliability are at the core of everything we do, which is why we implement advanced quality control measures. We also provide comprehensive engineering support for design and material selection to ensure only the highest-quality components are delivered.
Advantages of Ceramic Metallization
Offering several advantages over traditional manufacturing methods, ceramic metallization has become an indispensable process in precision metal manufacturing. These advantages mainly come down to the versatility, customization, and specialization this powerful process provides.
Material Versatility and Customization
Engineers benefit from a wide range of metal choices for metallization, such as gold, silver, platinum, and nickel, allowing them to tailor properties to specific application needs. This versatility is particularly beneficial in enhancing the corrosion resistance of ceramics, which is crucial for applications exposed to harsh environments, like aerospace and medical industries.
Metallization also significantly improves the electrical and thermal conductivity of ceramics, enabling their use in high-performance electronic components where efficient heat dissipation and reliable electrical connections are essential. These combined benefits ensure that metalized ceramics deliver superior durability, performance, and reliability in demanding conditions.
Specialized Coatings
Additional plating options ensure that metalized ceramics can meet the diverse and demanding needs of advanced aerospace and medical technologies, providing enhanced performance, durability, and reliability.
Silver plating is highly valued for its exceptional electrical conductivity, making it ideal for components that demand efficient signal transmission and minimal electrical resistance. Besides its excellent electrical conductivity, nickel plating has excellent adhesion properties, making it an ideal choice for brazing applications requiring strong, reliable joints. The superior corrosion resistance and biocompatibility of gold plating make it an excellent choice for medical devices and components exposed to harsh environments.
Despite its numerous benefits, certain limitations need to be considered when choosing ceramic metallization.
For example, ceramic metallization presents certain geometric constraints that can affect the design and application of metalized components. The process of applying a metal layer onto a ceramic substrate often requires uniform coverage, which can be challenging on complex geometries with sharp edges, deep recesses, or intricate patterns. These geometric limitations can result in uneven coating thickness, leading to potential weak points in electrical connectivity or mechanical strength.
Maintaining adherence to the metal layer on curved or irregular surfaces can be also difficult, requiring the use of advanced techniques and meticulous quality control to ensure reliability.
Understanding these geometric constraints is essential for engineers to design components that maximize the benefits of ceramic metallization while ensuring consistent performance and durability.
Ceramic Metallization Experts: Elcon Precision&#;s Unique Capabilities
Continuously innovating and evolving its processes in coating techniques, material formulations/testing, and quality control, Elcon Precision is leading the way in ceramic metallization.
Offering a full turnkey solution, our end-to-end services cover everything from material sourcing right through to prototype testing.
Collaborating with an array of approved ceramic vendors, we shorten the machining LT of the ceramics and offer better metallization lead times as well. We also ensure the highest levels of performance and reliability through advanced quality control measures and comprehensive engineering support. In addition to our stringent quality standards, we are also ASD-certified, ISO :-certified, ITAR-registered, and RoHS-compliant - proving our commitment to industry-best quality.
Do you need a proven partner for your next ceramic metallization project?
Our team is here and ready to start talking, whatever your application may be.
Request a quote today to send us your thoughts and get your project moving.
If you want to learn more, please visit our website metallized ceramics.