Skip to content

What are the Design Guidelines for Micro Circuit Boards?

The electronics world will soon implode and this will be caused by great improvements in how electronic products function or a huge size reduction. This will lead to miniaturization of PCBs. Below are some tips that will explain to you how to design and manufacture small circuit boards.

Today, reduction in size in basic printed circuit boards will assist the designer in reducing their PCB size by a quarter or by half of its initial size. With smaller vias and traces, there will be a need for new design rules, because the manufacturing of printed wiring boards is more advanced and different.

Moving to a reduced line width may catch some old fashion fabricators of printed circuit boards off guard. In order to stay competitive even in the future, any PCB shop should offer about 50-micron spaces and lines or even reduced to 30.

How to Design Small Circuit Boards

For some clear reasons, fine lines of about 30 microns can never make use of the usual one-ounce copper layer. As the line width is reduced the thickness must reduce as well. Copper traces that are thinner ought not to pose an issue unless you need high current for your design. In this case, you can use a wider specific trace to help handle this higher current.

Furthermore, a line of 30-micron is reliable and tough. However, it doesn’t have the strength to take much physical abuse which you can nearly eliminate by using a solder mask.

These fine traces may be worrisome for many designers. However, they must know that the initial wide trace of 200-micron they begin with will drop to about 25 ro 13-micron gold or aluminum round wire. This wire helps in connecting the chip carrier to the die.

There have been new methods to adhere copper to the surface of the circuit board, and are useful in improving the general adhesion of the micro trace into the surface.

For small vias, a physical limit regarding the size exists. Below 2 mils or 50 microns, that solution won’t plate that hole wall properly. This results in a poor quality via. Furthermore, the laminate’s thickness controls the via’s minimum diameter.

The microvia as a whole isn’t bad. It may be smaller compared to the traces, however, sweeteners can be added to the pot since the microvia’s annular ring can be smaller.

Making use of new technology for your small printed circuit boards rather than the usual circuit boards technology will lead to significant savings in real estate.

What are the Design Guidelines for a Micro Printed Circuit Board?

Below are the design guidelines for a micro circuit board.

Microvias

When making use of HDI technology, copper layers are added to the top of the multilayer board or as a HDI multilayer. Microvias are useful in connecting between these thin layers. You can drill the through-holes 5.9 mils in and a diameter with a thickness of 60 mils or you can use laser drilled hole with a diameter of about 2 to 3 mils thick.

Hole Sizes

Note that all the elements of a traditional design for a PCB have to be adjusted in order to fit the micro’s smaller size. This could become a challenge for layout engineers of PCB that know much about the traditional design of pcbs. One very common error here is including over-sized holes. If the design has too large holes, which usually happens, this leads to non-functioning or suboptimal micro PCBs.

Copper Thickness

The usual pattern plating is useful in manufacturing micro circuits. This means that the trace doesn’t need to leave the circuit. Pattern plating helps in connecting the whole circuit. Wire bonding plating on the other hand is electrical or electroless.

Electrical Testing

A rigid probe or flying probe’s lower limit is at 2 to 3 mil pitch. Over time, we expect that this drops as smaller landing pads are necessary. If the micro printed circuit boards feature smaller points like edge strip connectors, then it is advisable that the lines are extended off the circuit.

Reliability

Majority of normal laminates for printed circuits are useful for microcircuits or HDI. However, they all have limitations. You can manufacture micro double-sided or single circuits out of strong and rigid FR4 laminates. However, they must be thin to permit micro through-holes.

Security Marking

You can image small bar codes into solder mask to identify PCBs positively. Note that bar codes may be extremely small that they are invisible to the eyes.

Know the Capabilities of the Manufacturer

This is a very important step when working on micro PCB designs regardless of the microelectronic type of specific application you wish to develop.

Note that this tip is very relevant whenever you want to start anything related to PCB design. However, knowing the manufacturer’s services and capability is very important for your micro PCB. This is very important for companies that have never engaged in designs of micro PCB or teamed with a specific firm involved in PCB fabrication.

The reason is because the capabilities of the fabrication of micro pcbs vary with respect to the PCB manufacturer. The fact is that micro PCBs are still new and are complex so a good number of PCB manufacturers will provide limited or no support or microelectronic capabilities. Therefore, you will need to be sure that the manufacturer has what it takes to meet all your requirements.

Circuit Boards Necessary for Small Applications

Your size of circuit board depends on the design. Creating the layout of the integrated circuits is necessary, and you can make use of a computer aided design software. With this, you will be able to reduce your circuit board size easily. The spaces present between two electrical conducting paths are 0.006” or even smaller.

Furthermore, the dimension of a printed circuit board has to do with the circuitry and enclosure which houses the printed circuit board. Also, it determines the fixed components and heat sinks of the circuit board. Using the software, it becomes easy to reduce the circuit board size. It is advisable to ask the manufacturer to reveal the smallest possible size of circuit board they have the ability to make.

In addition, the circuit board size has to do with the space available for the enclosure. If the gadget you are designing is tiny, then you have to make use of small circuit boards. However, note that when creating a design for your small PCB, it will also use small electronic components. This could mean that you have to solder them using a fine tip soldering iron as well as close-up glasses or microscope, most especially when the clearances of these holes are tight.

Tips to Create the Smallest PCB Possible

When you are designing a printed circuit, there are some factors you should consider like text size, minimum width for the silkscreen, minimum width for the trace, minimum clearance for the solder mask, solder paste/minimum vias/pads/trace space, as well as the finish and drilling hole. Note that these factors aid the determination of the minimum circuit board size.

Also, make sure you consider the buried and blind vias carefully at all times. This is because they have a great impact on the design and they can engineer the PCB to become very small. Vias help in connecting the traces between the board layers, while traditional options decrease the routing space available on the board.

To maximize the routing space and to avoid any large size for your board, we advise that you search for alternatives. Blind vias help in connecting internal and external layers with reduced spacing. Furthermore, buried vias can help in connecting multiple internal layers; however, they don’t reach out to external layers. This then limits the overall requirement for the space and will present you with a product that is more stable.

Also, check out the spacing present between these components. When you bring them closely together, there might be no room for trace routing. When the component has more pins, then it will surely require more space. With proper spacing, soldering the components onto the circuit board becomes easier.

In addition, components have to stick to the usual pin numbering design standard. This ensures that everything is equally oriented. This also reduces the possibility of errors during soldering and inspections. With this, manufacturing concerns are limited and this also helps you to remember everything as you undergo size reduction.

Applications of Small PCB

As electronic gadgets keep experiencing continuous miniaturization, this has caused or driven printed circuit boards into becoming denser and smaller, as well as requiring more capabilities. Now, the smallest PCB size is now the norm. This is because more small PCB design manufacturers now make use of integrated circuit chips.

Smallest PCB size is useful in different applications and industries including

Conclusion

Due to technological advancements, manufacturers now lead more towards small circuit boards. RayMing PCB is an experienced manufacturer and developer of small PCBs. It also focuses on customer services and industry tolerances. We offer professional services that can adjust quickly to meet low- or high- volume demands that may be available for small PCBs.

Contact us today on how we can help you design a reliable small PCB for your needs. You can ask for our different pricing options that meet your budget.