The Ultimate Guide to Ceramic PCBs

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Nov 4, 2019|General

Ceramic circuit boards offer a host of benefits over traditional printed circuit boards (PCBs). Due to its high thermal conductivity and minimal expansion coefficient (CTE), ceramic circuit boards are more versatile, less complex, and offer superior performance compared to regular PCBs.

Want to find out more about ceramic PCBs and how they can make a positive addition to your company’s overall system costs? In this article, we cover everything there is to know about ceramic PCBs, the various types available, and their respective use cases.

Pros & Cons of Ceramic PCBs

Pros:

• Excellent thermal conductivity
• Resists chemical erosion
• Compatible mechanical intensity
• Easy high-density tracing implementation
• CTA component compatibility

Cons:

• Higher cost than standard PCBs
• Lower availability
• Fragile handling

Types of Ceramic PCBs

High Temperature

Perhaps the most popular type of ceramic PCB is the high-temperature PCB. Ceramic circuit boards designed for high temperatures are often referred to as High-Temperature Co-fired Ceramic (HTCC) circuits. These circuits are constructed by mixing adhesive, lubricant, solvent, plasticizer, and aluminum oxide to create raw ceramics.

With the raw ceramic material produced, the material is then coated, and circuit tracing is implemented on tungsten or molybdenum metals. Once implemented, the circuits are baked between 1600 and 1700 degrees Celsius for up to 48 hours after lamination. All HTCC baking is done in a gaseous environment, such as in hydrogen gas.

Low Temperature

Unlike HTCCs, low-temperature co-fired ceramic PCBs are produced by combining crystal glass with an adhesive substance on sheet metal with gold paste. Then, the circuit is cut and laminated before placed in a gaseous oven at roughly 900 degrees Celsius.

Low-temperature co-fired ceramic PCBs benefit from less warpage and improved shrink tolerance. In other words, they have a superior mechanical intensity and thermal conductivity compared to HTCCs and other types of ceramic PCBs. The thermal benefit of LTCCs provides an advantage when working with heat-emitting products, like LED lights.

Thick Film Ceramic

Thick film ceramic circuits involve gold and dielectric pastes that are implemented on a ceramic base material. Once implemented, the pastes and baked at a temperature of 1000 degrees Celsius or below. This variety of PCB is popular among major printed circuit board manufacturers due to the high cost of gold conductor paste.

The main benefit of thick film ceramic material over traditional PCBs is that thick film ceramic prevents copper from oxidizing. Therefore, a ceramic PCB manufacturer can benefit from choosing thick-film ceramic circuits if they are concerned about oxidation.

We’re often asked, “how many layers is a ceramic PCB?” However, the answer depends on the type of ceramic PCB used. The minimum number of layers utilized in a ceramic PCB is two, but there may be several more depending on the product’s properties. A trace width calculator can help manufacturers understand the specifications of their PCB design.

Use Cases for Ceramic PCBs

Memory Modules

One of the key application fields of ceramic PCBs has to do with memory modules. These PCBs have memory integrated circuits that are commonly used in the production of DDR SDRAM and other computer components related to memory. All RAM used in personal computers requires ceramic substrate PCBs with integrated memory modules.

Receiving & Transmission Modules

The production of radar technology is made possible by ceramic PCBs. The American firm Westinghouse was the first to create transmission and receiving modules using multi-layer ceramic PCBs due to their high thermal conductivity and compatible CTE. Unlike regular PCBs, ceramic circuits are the only kind that are useful in the creation of transmission modules.

Multilayer Interconnect Board

One of the key selling points of ceramic PCBs is that they have a greater capacity than regular circuit boards. In other words, ceramic PCBs can hold more components using the same amount of surface area than a conventional PCB. Therefore, ceramic PCBs have a greater number of potential applications using a multi-layer interconnect board.

Analog/Digital PCB

Various computing firms have used low-temperature ceramic circuit (LTCC) boards to create superior analog and digital boards with superior circuit tracing. Personal computer companies have utilized LTCCs to create a host of lightweight circuits that reduce the total weight of the product and minimize crosstalk interference.

Solar Panels

HTCCs and LTCCs alike are used in the manufacturing of solar panels and other photovoltaic (PV) electrical panels. PV panels utilize multilayered ceramic board technology to ensure longevity and adequate thermal conductivity.

Electric Power Transmitter

Wireless power transfer and charging modules are becoming increasingly common consumer electronics devices. These devices are constructed using ceramic PCB technology because of their unique thermal properties and heat-dissipation ceramic substrate.

Ceramic circuit boards are used to create an electromagnetic field with which to transfer energy between a receiver and a transmitter. Induction coils facilitate the transfer of electricity from the original electromagnetic field and convert it into an electrical current for the receiver circuit. Often, the receiver circuit is made of ceramic-based PCB materials.

Semiconductor Cooler

More and more electronic devices are becoming miniaturized. Behind the miniaturization of consumer electronics are semiconductor chips, which are getting smaller and smaller every year. Semiconductor chips use micro-fabrication technology to allow for higher integration at high speeds while maintaining optimal tracing capabilities.

Traditional PCBs cannot facilitate the number of circuit functions required of modern-day semiconductor chips. However, the advent of ceramic-based semiconductor circuits has led to superior integration and performance among miniature circuit assembly. Therefore, ceramic PCB substrates are often considered the future of semiconductor technology

High Power LED

Ceramic substrates provide an optimal submount for high power LED lights. Unlike conventional PCBs, ceramic circuits use thick film technology to maximize thermal efficiency. The result is that the heat produced by the LED light (LEDs are roughly 70% heat) does not impact the circuit operational efficiency.

In other words, only ceramic circuits offer the level of thermal efficiency required for LED light production. When LEDs are built on ceramic circuits, thermal interface materials, also known as heat sinks, are not required. Therefore, there are fewer materials needed to produce and maintain LED light if the manufacturer uses ceramic circuitry.

Ceramic PCB Types

Alumina

Also known as Al2O3 and metal base PCB, Alumina is a PCB type that utilizes dielectric thermally conductive and electrically insulated material between the aluminum metal and the copper layer. It is the PCB of choice for anything that involves heat dissipation as well as overall temperature maintenance and control.

Aluminum constructions are usually made up of three layers.  A circuit layer made of copper around 1 to 10 oz. thick, an insulating layer made of thermally conductive and electrically insulated material, and a base layer made of copper or aluminum metal substrate.

Aluminum PCBs come in several types.  There’s the Flexible type, the Hybrid, the Multilayer, and the Through Hole types.

AIN

Also known as Aluminum Nitride, AIN is a new material that has been developed into a commercially viable product.  It comes with properties that are both reproducible and controlled within the last two decades.

AIN is an effective choice because of its good dielectric properties, low thermal expansion coefficient, high thermal conductivity, and its non-reactiveness with common semiconductor process chemicals, among others.

Aluminum Nitride PCBs are commonly used in heat sinks, microwave device packages, molten metal handling components, substrates for electronic packages,  and semiconductor processing chamber fixtures and insulators, just to name a few.