Archive for the ‘DBC substrate’ Category

Laser drilling and cutting in the production process of ceramic circuit boards

Monday, July 12th, 2021

In the ceramic circuit board processing and production process, laser processing mainly includes laser drilling and laser cutting.

Ceramic materials such as alumina and aluminum nitride have the advantages of high thermal conductivity, high insulation and high temperature resistance, and have a wide range of applications in the fields of electronics and semiconductors. However, ceramic materials have high hardness and brittleness, and its molding and processing are very difficult, especially the processing of micropores. Due to the high power density and good directivity of the laser, lasers are generally used to perforate ceramic plates. Laser ceramic perforation generally uses pulsed lasers or quasi-continuous lasers (fiber lasers). The laser beam is focused on On the workpiece placed perpendicular to the laser axis, a laser beam with high energy density (105-109w/cm2) is emitted to melt and vaporize the material. An air stream coaxial with the beam is ejected by the laser cutting head to remove the melted material from The bottom of the incision is blown out to gradually form a through hole.

Due to the small size and high density of electronic devices and semiconductor components, the precision and speed of laser drilling are required to be high. According to the different requirements of component applications, electronic devices and semiconductor components have small size and high density. Due to its characteristics, the precision and speed of laser drilling are required to be high. According to the different requirements of component applications, the diameter of the micro-hole is in the range of 0.05 to 0.2 mm. For lasers used for ceramic precision processing, generally the focal spot diameter of the laser is less than or equal to 0.05mm. Depending on the thickness and size of the ceramic plate, it is generally possible to control the defocus to achieve through-hole punching of different apertures. For through-holes with a diameter less than 0.15mm, drilling can be achieved by controlling the defocus amount.

There are mainly two types method for cutting ceramic PCB: waterjet cutting and laser cutting. Currently, fiber lasers are mostly used for laser cutting. Fiber laser cutting ceramic circuit boards has the following advantages:

(1) High precision, fast speed, narrow cutting seam, small heat-affected zone, smooth cutting surface without burrs.

(2) The laser cutting head will not touch the surface of the material and will not scratch the workpiece.

(3) The slit is narrow, the heat-affected zone is small, the local deformation of the workpiece is extremely small, and there is no mechanical deformation.

(4) The processing flexibility is good, it can process any graphics, and it can also cut pipes and other special-shaped materials.

Al2O3 PCB with drilling
AlN PCB with drilling

 Under the development trend of light and thin, miniaturization, etc., the traditional cutting processing method has not been able to meet the demand due to the insufficient precision. Laser is a non-contact processing tool, which has obvious advantages over traditional processing methods in cutting process, and plays a very important role in the processing of ceramic substrate PCB.

Please contact sales@bestpcbs.com if you want to know more ceramic PCB.

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The technology and application of DBC ceramic PCB

Thursday, June 17th, 2021

DBC means direct bonding copper, it is a ceramic surface metallization technology.

The copper is bonded on Alumina, Beryllium Oxide and Aluminum Nitride, Packaging applications for power electronic modules, semiconductor refrigeration and LED devices are widely used.

DBC-Ceramic-PCB

96% Al2O3 has good insulation, good chemical stability, high strength, and low price. It is the preferred material for DBC technology, but the thermal conductivity of aluminum oxide is low, and there is a certain thermal mismatch with the thermal expansion coefficient of Si.

BeO is a good ceramic material used in DBC technology. It has high low-temperature thermal conductivity. It can be used for medium and high power devices. In the application field and process, the toxicity caused by it should be properly protected.

AlN material is non-toxic, moderate dielectric constant, thermal conductivity is much higher than aluminum oxide, close to beryllium oxide, and thermal expansion coefficient close to SI. All kinds of chips and high-power devices can be directly attached to the AlN substrate. No transition layer of other materials is used. The prospects currently used in DBC technology are very promising.

There is no any layer between the metal and ceramic substrate, so the thermal diffusion ability is strong; the contact resistance is also low, which is conducive to the connection of high-power and high-frequency devices.     

The linking temperature is lower than the melting point of copper, and the DBC substrate maintains a stable geometric shape during the connection process. In some cases, the copper foil can be made into the required shape before the linking, and then the DBC preparation process is performed, eliminating the need After connecting the etching process.

The copper conductor part has a very high current-carrying capacity, so it has the ability to reduce the size of the intercepting medium and increase the power capacity.

If you want to know more about DBC ceramic PCB, please feel free to contact sales8@bestpcbs.com

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Do the vias can be filled for ceramic PCB?

Friday, November 13th, 2020

As everyone knows for FR4 PCB, people like the vias to be tented or filled for some special applications.
Ceramic PCB is more and more popular because of the thermal conductivity is very high and very good for heat dissipation. Most of customers are going to make the PCB with ceramic material, includes Al2O3, AlN, BeO or Si3N4, etc.
So do the vias can be filled for ceramic PCB becomes the frequently asked questions (FAQ).
The answer is YES.
So what’s the material can be filled in vias for DBC/DPC alumina PCB/ Aluminium Nitride PCB?

The material can be solder mask, Dow Corning 1-4173 and copper/Cu.
Normally, customers want the vias/holes to be filled with copper.
Because copper can fill the vias very well and it is easier to do and it looks very good. Please see below photo.
The left one with filling with copper, the right one without filling copper

Why you need to fill the vias with copper?
1.Becuase if let the vias open, they will allow solder to flow through to opposite side of PCB during reflow, this causes bridging under components.
Filling the open vias/holes with copper can prevent from the solder pates into the vias.
2.If you need to pull vacuum around them and a hole would compromise that, so need to fill the vias.
There are also other purposes for filling the vias, if you need such ceramic board with filling the vias, please contact Coco in Best Technology sales@bestpcbs.com

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