Your Valuable Ceramic PCB Manufacturer in China

We can categorize Ceramic PCBs in two ways. According to layer numbers and thermal properties.

Types of Ceramic PCB

According to Layers

Single-Sided PCB

In a single or one-sided PCB, one side of the board contains a conductive component. On the other side of the board, you will discover conductive wiring.

As it comes with only one layer, it is the most straightforward kind of ceramic PCB, and you only can use this for the simplest devices.

Two-Sided PCB

As the name suggests, you will find two conductive layers in these types of ceramic boards. Here you can see the conductive layers mounted on every side of the PCB board.

The additional layer allows the traces to go over one another. As a result, you can build a very dense circuit needlessly to solder them from one point to another.

They are not as simple as one-sided ceramic boards, and you can use two-sided ceramic PCBs for many different applications.

Multilayer PCB

Multilayer PCBs have more than two layers, making them more versatile than other types of ceramic PCBs.

You can use these PCBs in more complex applications.

According to Thermal Properties

High-Temperature

As you can guess, these ceramic PCBs are designed to handle those applications that generate high temperatures, and that’s why they are called HTCC or High-Temperature Co-fired Ceramic.

It is made of raw ceramics with mixing adhesive, solvent, lubricant, plasticizer, and aluminum oxide.

Low-Temperature

Manufacturers use a highly conductive gold paste sheet metal and combine crystal glass with adhesive substrates. Then they cut the board and laminate it.

Then they heat the board at about 900 degrees C.

Low Thermal Co-fired Ceramic or LTCC comes with superior thermal conductivity and mechanical intensity to HTCC.

Thick Film Ceramic PCB

In this type of ceramic PCB, the conductor layer’s thickness is between 10 microns to 13 microns.

You will find thick film gold and alternative dielectric paste on the ceramic board’s surface.

Thick film ceramics are heated at 1000 degrees C, which is ideal for large-scale fabrication. But as gold is highly-priced, most manufacturers avoid large-scale fabrication.

Manufacturers also use nitrogen gas in the backing process to safeguard the ceramic PCB from oxidation. This is a crucial advantage that thick ceramic PCB provides over traditional PCBs.

Standard PCB boards are built with FR4, polystyrene, etc. But ceramic PCB is made with other materials that add unique properties to this board. Some of them are:

• They are excellent thermal conductors.
• Chemicals can not erode the ceramic PCB quickly.
• They come with superior mechanical intensity.
• You can execute high-density tracing quickly on ceramic PCBs.
• They have very CTA element compatibility.
• They safeguard the copper from oxidation.

Ceramic PCBs provide many advantages over standard PCBs. Some of the benefits are:

High Thermal Expansion

They have a high thermal coefficient expansion, and for this reason, they are widely used in the electronic industry.

Ceramic PCB’s thermal conductivity can be compared to silicon, but they are not as conductive as metals.

Moreover, ceramics can act as an excellent isolator for a brief amount of time.

As a result, ceramic PCBs can produce optimum conductivity even under a high-temperature situation. This is why ceramic PCBs can be used on many devices.

Ceramic PCB Advantages

Stability

Ceramic PCBs have a steady dielectric property that comes from the ceramic.

This dielectric property can switch into a bit of radiofrequency loss, which is a big reason for the increasing use of ceramic PCBs.

Furthermore, ceramic PCBs are naturally protective against many chemicals, adding an additional toughness to the board. How?

As they are resistant to chemicals, they are protective against solvents, daily moisture, and other consumables.

Versatility

Ceramic PCBs can operate in multiple devices with various temperatures. You can use it for devices that produce high temperature and also low temperature.

Moreover, ceramic PCBs can distribute heat to the different parts of a device using its excellent thermal conductivity.

Durability

With ceramic PCBs, you don’t have to worry about daily wear and tear. The fabrication process of ceramic printed circuit boars makes them durable and come with slow aging chemical properties.

Therefore, you don’t have to replace the PCB board any time soon. Moreover, its high thermal resistance allows a delayed decomposition process which significantly increases the lifespan of ceramic PCBs.

Adaptability

This is the most prominent advantage of ceramic PCBs. Manufacturers engineer metal cores in ceramic PCBs.

As a result, these PCBs provide mechanical stiffness, which makes them easy to use between solids and fluids. Therefore, metal core PCBs are highly adaptable, and you can use them for various industrial applications.

Every PCB has its advantages and disadvantages. Though ceramic PCBs come with many benefits, they also have some drawbacks. Some of the disadvantages that ceramic PCBs have are:

Expensive

We can not say it is an overall disadvantage actually, but for some industries, it can be a disadvantage. The manufacturing process involves many operations, which increases the price. Moreover, the materials that are used in ceramic PCBs also increase their price.

Fragility

This is a crucial problem that you have to face with ceramic PCBs. For this property, the size of the PCB boards is limited.

The reasons for the growing popularity of ceramic PCBs are as follows:

● Operating Temperature

You can use them for your devices that run under tremendously high temperatures. That is why ceramic PCBs are different from standard PCB boards, which fail to operate when exposed to very high temperatures.

Want to know the amount of temperature that a ceramic printed circuit board can handle? Well, if your device produces 350 degrees Celsius, the ceramic PCB will tackle it quite comfortably.

Why Ceramic PCB

● Expansion Coefficient Is Low

The thermal coefficient is crucial as a higher coefficient can distort the device. As ceramic PCBs have a lower expansion coefficient, they pose less risk of device distortion.

Covalent materials such as carbide, silicon nitride, diamond, etc., establish stronger bonds resulting in a lower expansion coefficient.

● Excellent Thermal Properties

Ceramic PCBs can conduct heat with excellent efficiency. Moreover, ceramic boards have high thermal consistency, which is a vital electrical property to have in your devices.

● High Modulus

Devices working under fluctuating temperatures can work more efficiently because of this feature of ceramic PCB.

● Mighty High-frequency Performance

You can get excellent high-frequency performance from ceramic boards. Determining the bandwidth and impedance of the transmission path is an essential factor. Ceramic PCBs can enhance the frequency performance with their dielectric material because they are limited.

● Cost-effective

The materials you can use in ceramic PCBs reduce the need for tests and insertions, which is mandatory for other circuit boards. Compared to other PCB boards, they need a shorter assembly process.

● Small Package

Ceramic PCBs can include a large number of circuits in a tiny space. Therefore, compared to other PCBs, you can manufacture your ceramic PCBs in smaller packages. This also fastens the integration process.

● Zero Water Absorption

With zero percent water absorption, you can make airtight packages with ceramic PCBs.

Here are some tips on how you can improve thermal management in a metal core PCB:

• Construction or design: it’s better to separate signal conductors and high power. Enlarge the copper thickness and use additional thermal vias.
• Heavy Copper PCBs: Copper has an excellent thermal conductor. Heavy coppers like 10oz, 20oz, 30oz enhance heat dissipation.
• Aluminum-Based PCB: The thermal conductivity of aluminum base PCB is 1W/m·K to 3 W/m·K. Aluminum can disseminate heat pretty quickly.
• Copper-Based PCB: Copper has more thermal conductivity than aluminum ranges from 4W/m·K to 7W/m·K. This base disseminates heat much more efficiently than aluminum-based PCB.

Ceramic PCBs come with higher capacity than standard PCBs, which is their key selling point. You can use more components in the same circuit area in a ceramic PCB than a conventional standard PCB. Therefore, the number of potential applications is higher when you use ceramic PCB for multilayer boards.

Those industries that need good heat resistance with higher frequency connections always prompt ceramic PCBs. Industries that use plenty of ceramic PCBs are:

• Automotive
• Aerospace
• Heavy machinery
• Medical devices
• Electronics

Ceramic PCB substrate for automotive

Many other industries also use ceramic PCBs depending on the design and the requirements of the circuit board.

They are different from standard FR4 PCBs. So, you have to follow a different procedure to design a ceramic PCB. Here are the steps to design:

Alumina ceramic PCB

Step 1: First, you have to source conductor materials. Usually, they are copper between 0.1 mm -0.3mm thickness.

Step 2 – Make sure you follow the recommended thickness for copper against width and trace space. For example, the width and trace space have to be.3mm if the copper thickness is .1mm, while the copper thickness is .2mm, you will need .4mm width and space.

Step 3 – You should make sure that you have ample working area. 126 x 176 mm. is recommended.

You will find two primary substrates for ceramic PCBs. They are AIN and AI203. And the substrate’s thickness should be .25mm. You can also design for higher thicknesses such as .38,.50,.63,.76 mm. You can design the thickness to 1.0mm for AI203 and 1.27 for AIN.

Step 4 – Now that you have achieved the substrate thickness, make sure to leave a .3mm margin between the board’s edge and the trace. You should do it on every side at a .1mm interval of the copper thickness.

For .2mm copper thickness, you should leave a .4mm margin and .5mm margin for .3mm copper thickness.

Step 5: You have nearly designed the ceramic PCB. Now it’s time to conduct the surface finishing procedure. You should use Nickel for the surface finish. Aug-plating is another option that you can use.

Making mistakes in PCB design? Watch the video to resolve

Let us inform you of the manufacturing process of ceramic PCB. Here is how it is done:

The Design

The manufacturing process starts with the design for the ceramic PCB you want to manufacture. You can use PCB design software such as AutoDesk to design your ceramic PCB. You can also use a trace width calculator, which comes with your PCB board’s inner and outer layer details.

Printing the Design

After completing the design, it’s time to print it, and you can use a plotted printer to print your design. This will create the print with the details of each layer.

 Components of ceramic PCB

Substrate Creation

Semi-cure the substrate through an oven. This process will pre-bond copper to the layer of both sides. You can etch it later to let out the design of the PCB.

Printing Of Inner Layers

Use a photosensitive film produced from photoreactive chemicals and mount. After exposing it to ultraviolet light, it will harden. After finishing the process, the blueprints become aligned to the board’s actual part.

Ultraviolet Light

You have to take the board past ultraviolet light after you have completed aligning the resist part. This will harden the photoresist.

Use alkaline to wash the board, and that will remove any unnecessary copper and leave the photoresist intact.

Layer-up and Bond

At this stage, the layers are ready for their fusion. The substrate is usually joined to the outer layer. You will have to use two steps in this process: layering and bonding.

Materials of the outer layer include substrates surrounded by thin aluminum foil on both sides. There is also copper tracing in the substrate.

Now to bond the layers together using a heavy steel table and metal clamps.

Then securely fit the layers into pins on the table. Make sure you include them perfectly so that they don’t shift during alignment.

After placing the layers on the table, you can add a prepreg layer on the alignment resin. Before you place the copper sheet, adjust the substrate layer onto the prepreg.

To complete the stack, use a copper press and aluminum foil. The next step is pressing.

Drill

Now you can drill holes into the board. The drilled holes must be of a hair width. Identify the target spots with an x-ray locator. You should use buffer material under the board while drilling for a clean bore. Computer-aided drilling machines are lightning-fast, but you should take care of every hole very carefully.

Copper Deposition And Plating

This is the step where you can fuse multiple layers. After cleaning the panel thoroughly, go through several chemical baths to proceed with the washing.

The chemical deposition procedure will place copper on the panel’s surface. Usually, it is very thin (1 micron). The copper will enter into the holes you drilled earlier.

Imaging Outer Layer

You will have to apply the photoresist panel again in this step.

Pass the panel into a yellow room. That light doesn’t have UV levels to affect the photoresist.

After the stencil and the panel contact each other, a high UV light will blast them.

To remove the unhardened resist, you must use a machine and pass the panel through it. Here you will also take over the inner layer.

Now remove all the unnecessary photoresists and observe the outer layer.

Plating

Use your plating room again and use a tiny copper layer to electroplate the panel. The exposed panel in the photoresist stage of the outer layer will get copper electroplating.

Now it’s time to perform tin plating over the panel. This will remove all copper remains.

Final Etching

You have to use some chemical solutions to eliminate unwanted copper from below the resist layer and keep only the necessary copper. Tin will safeguard the essential copper in this step. In this stage, you establish the connections and conducting areas.

Solder Mask Application

You should clean the board properly before applying the solder mask application. Expose it to the ultraviolet light after covering it with epoxy solder mask ink.

Complete the solder mask process. The ink-covered portion will remain unhardened, and you can remove it to remove the solder mask using an oven.

Surface Finish

You can chemically plate the ceramic PCB board with either silver or gold. Manufacturers prefer silver as gold will increase the manufacturing cost.

Silkscreen

You are almost done with your ceramic PCB board. Pass it for the last coating and curing.

Electrical Test

Testing will confirm that everything is working fine and you have got the board just as you designed.

Profiling and V-Scoring

Cut the different boards from the manufactured panel. You can use a v-groove or router to complete the cutting process.

Below are the precautions used during the ceramic PCB fabrication process:

Lighting

The fabrication process of ceramic PCB is complicated; therefore, you should place proper lighting in the working area to work with utmost efficiency.

Pins and Forks

Always use proper sized forks and pins because you have to deal with various small components. This will ensure that no components get damaged.

PCB material

Safety Gear

Always wear appropriate safety gear to be well protected in the whole process.

Wear goggles to protect your eyes from flying particles in the fabrication process. And don’t forget to wear hand gloves to protect your hand from damaging chemicals and acids. Besides, the gloves will also help you to grip firmly.

Check Connections

Ensure all the power sources are working perfectly. You should check if there are any voltage compatibility issues. This is IMPORTANT because any failure here can cause a short circuit and, as a result, produce electric shocks.

Components installation

You should also check the installation and connections because any loose connection or faulty installation can lead to a short circuit and produce electric shock.

Know more on PCB fabrication

Prototyping is the pre-step of the actual assembly of your ceramic prototyping. Here are the steps of ceramic PCB prototyping:

Stenciling Solder Paste

Apply solder paste over the board after mixing the flux and paste. This process will bond the surface over the board.

Stenciling will curve out the designed points, and then you will apply the solder paste.

Pick and Place

Fix the surface mount components using a pick and place machine. The device will allow you to place the components on the exact location of the design.

Reflow Soldering

Now put the boar in the reflow oven and pass so that the solder paste melts perfectly. First, apply heat and then reduce the temperature so that the molten solder solidifies. For a two-sided ceramic PCB, you have to proceed with reflow for every side.

Quality Control and Inspection

Inspection will find any error on the board. You should expose any flaw at the early stage.

You can pick from various inspection methods such as automatic optical inspection, manual examination, x-ray inspection, etc.

Through-Hole Components

If the design has through-hole components provision now, you can insert them. Solder the components with a wave soldering technique. You might have to use manual soldering for specific components. For both sides, soldering takes extra precautions for the second part to avoid any damage to the board.

Functionality Test

After finishing all processes, run a functionalities test to detect problems and resolve if you find any.

LED industry use metal core PCBs for various applications because:

• For their stability, they are best for high-density applications.
• They are more efficient in dissipating thermal heat compared to FR4 PCB.
• They are not vulnerable to heat distortion.

Here are the steps of the assembly process of ceramic PCB board:

• Use a computerized design system to check the layout so that you can identify any overlooked malfunction.
• Before starting SMT assembly verify all the incoming boards such as model number, BOM list quantities, etc.
• Use solder paste before attaching the components to the board.
• Utilize a pick and place machine to place every surface component on the board,
• Pass them into the reflow machines to melt and solidify the soldering paste.
• Run several inspections and quality checks before final production.

Testing is crucial before using the final ceramic PCB. You can test a PCB in multiple ways.

Ceramic PCB substrate

Visually inspecting Solder Paste.

This is the best method of inspecting solder paste. You will get the following benefits from visual inspection:

• It reduces the time and cost if you need any rework of the board.
• The methods begin with solder applications.
• You will be 100% sure that the components are correctly reflowed.
• Minimizes wastages.
• This will prevent you from passing PCBs with solder badges.
• This process identifies fragile joints and open circuits that can create failure.

Reflow Inspection in Both Pre and Post Stage

The reflow actions are mandatory in both stages.

With the pre-reflow inspection, you can identify placement errors and correct them quickly. This step will help you to avoid the same mistakes twice at the early stage.

On the contrary, post-reflow inspection is the process of inspecting all the SMT feeders.

When you are searching for high thermal conductivity, you should pick aluminum nitride boards as they provide higher than 150 w/mK.

But as aluminum nitride boards are expansive, you can also use aluminum oxide boards, and they provide 18-36 w/mK.

You will get better thermal performance from both boards than metal core PCBs.

Some other options are beryllium oxide, silicon carbide, and boron nitride.

Also, you can use silver or gold to shield exposed pads.

Silver covered with glass protection for the printing traces can increase the thermal conductivity up to 406 W/mK.

You should consider many things before picking the best ceramic PCB manufacturer in China. Such as:

• How experienced and professional they are.
• The turnaround time must fit your plan.
• Fair pricing policy compared to other manufacturers.
• They must build both the prototype and the actual PCB
• Must follow the proper packaging process
• Able to ship your PCBs safely.

Ceramic PCBs have some significant benefits over other PCBs because of the base material they use.

Because ceramic PCBs are more efficient than other PCBs, you have to pick the best substrate and an experienced PCB manufacturer.