Cutting ceramic pcbs and the influence on edge quality & cost

There are several ways to cut ceramic PCBs into shape and they are for the most part different from other types of printed circuit boards. Depending on the shape of your design and your requirements, we will choose one or a combination of the standard or specials methods listed below.

Standard method #1 – Laser scribing

Preferred for straight edges. Possible for certain outward curves.

Definition: Laser scribing is a technique that allows for easy singulation of ceramic substrates/circuits from a manufacturing panel/sheet. As opposed to laser cutting, the laser beam does not go all the way through the material during a laser scribing process and the goal is to make a perforated line along which an easy and clean break out can be done.The main downside is that your design needs to have straight edges. In certain case we can use it for outward rounded corners as well but the corners need to be at least r≥3mm and thickness ≤1mm.

If you would like to learn more about this method, we dedicated a complete page explaining in detail what it is and how to use it in your design. (What is laser scribing?)

Edge Quality: As the cut is formed using a series of blind holes, the edge is relativity rough consisting out of 1/2 circles with a radius of 15 micron. This cannot be felt but can been seen under large magnification. Using post processes, the edges can be smoothed. Furthermore, as this cut goes almost straight down, taper is much smaller compared to cutting.

Costs: This method is the fastest and lowest-costs option we offer (if post processing deburring is not necessary for your application).

Standard method #2 – Laser Cutting

Necessary for inward corners, holes, and small features

Definition: Laser-cutting will use a powerful laser to go all the way through the material. It is a delicate process that needs to ensure enough power is used to remove material while avoiding overheating and cracking. The kerf also needs to be larger allowing the cut to go all the way to the other side which results in a larger spacing between designs on a panel.

Edge quality: Generally, laser cutting results in a smoother edge quality compared to laser scribing however it will create a tapered edges that is maximum 5 degrees for thicknesses ≤1mm (can be more for thicker boards).

Costs: As the process is slower, the costs are higher compared to laser scribing. This is why the shape matters

 

Special method #1 – Wafer dicing

For straight edges that need a smooth finish.

Definition: Wafer dicing using a diamond blade and cooling can be an interesting alternative for laser scribing when the edge quality / roughness needs to be improved. However, it will require the parts to be spaced further apart as the blade will remove material (typically 80-100um). 

Edge quality: Smooth edges with minimal to no taper

Costs: We offer this process via a partner and thus it will be slower and more costly then laser scribing for prototyping and low volumes. However, for high volume programs, the additional charge is minimal to none.

 

Special method #2 – Green Machining & punching

For special shapes and ultimate edge quality

Definition: When a part cannot be cut or shaped using laser or dicing, there is the option of machining and punching it in the green state and metalize it afterwards. This means that ceramic is formed when it is still relatively soft and before it is sintered.

Edge quality: as good as it gets. Given the shape of design is made before sintering there are no effects from laser processing or dicing.

Costs: The process will take time and require significant upfront costs as tooling is needed and the sintering phase needs to be engineered to control shrinkage of the design to meet dimensional tolerances. We therefore only recommend this when absolutely needed and for high volume programs.

 

We have extensive experience in deciding what is the best way to cut your ceramic pcb design so in most case you do need to worry about this. However, if you have specific requirement that rule out one of the methods above, please do not hesitate to contact us to discuss your design.