Laser drilling as an alternative for through-hole and microvia drilling

Laser drilling is increasingly replacing mechanical drilling methods. With advantages such as speed, accuracy, cleaner cuts and less debris 鈥?not to mention reduced mechanical stress on delicate components 鈥?laser drilling offers huge advantages to electronics manufacturers.

Before laser drilling, manufacturers relied on mechanical drills for all of their drilling needs, whether drilling cooling holes or creating tiny micro vias in PCBs.

However, as products and components become smaller, the drawbacks of traditional mechanical drilling are increasing. These include mechanical stress, messy debris that needs to be cleaned up, rough edges, and limitations on hole size. In short: the industry needs heroes. That鈥檚 where laser drilling comes in.

Why is laser drilling superior to other methods? With laser drilling, you never have to worry about a drill bit wearing out or breaking. The process is clean and debris-free. The edges are always sharp, allowing for ideal copper plating, and best of all, laser drilling is absolutely much faster than mechanical drilling.

Lasers can also drill small holes very accurately and can be used in hard-to-cut materials such as ceramics and gemstones, as well as most metals. They are also ideal for drilling through-holes as small as 40 microns in diameter.  

Our Laser Drilling Process, When you choose a laser cutting partner to work with, consider the requirements of your project in terms of beam quality, wavelength, intensity, pulse duration, and pulse repetition rate. Our engineers can review your project and help you make an informed decision. With our new laser systems, we can provide you with the highest quality drills and amazing delivery times. The laser is capable of drilling holes in the following materials:

Solder Mask:

This is the green layer you typically see. It is placed on top of the copper layer as a way of insulating the copper traces. This prevents accidental contact with other metals or conductive bits. This ensures that the right spots are soldered correctly. Typically, you'll see a green or red solder mask.

Silk Screen:

This is the white layer you see on top of the solder mask. This is what gives your board its symbols like letters and numbers. This is added to allow for a better understanding of the different areas of the board.

Substrate or FR4:

This is the base material of the board, usually fiberglass. This is how the board remains rigid but flexible. PCBs can come in different thickness grades but generally around 1.6mm. If you have a cheap PCB on your hands it will stink when you try to solder to it and it won't be flexible at all.

Copper:

The next layer is a thin copper foil, which is laminated to the board using heat and adhesive. PCBs can have anywhere from 1 to 16 layers of copper, and the thickness of the copper can vary.

We know how important tolerances are for high-end medical, aerospace, and military applications. We meet this demand by offering laser cut parts with tolerances within 0.0005" (12 microns).

The motion systems used in our UV laser systems are second to none in the industry, remaining stable year after year to ensure that the last batch is as accurate as the first.

Laser Drilling as an Alternative for Through- and Microvia Drilling

Just like a physical city where streets and roads connect buildings together, the ICs on a board are connected to each other by copper traces. Like any metropolis, urban sprawl tends to move vertically rather than horizontally, but instead of multi-story buildings, we get multi-story boards.

Through-holes are copper-plated holes that span across the different layers of a given circuit board or panel. They are the entrance locations to subway stations, if you will. Having these multi-layer boards enables electronic designs to dramatically reduce the size of the board without compromising complexity.

The holes for component leads and contacts are drilled into the circuit board using "through-hole drilling." This drilling has traditionally been done using a drilling machine, but more and more manufacturers are turning to laser machines.

Before the advent of automated computer software, circuit boards were made using point-to-point wiring and drill presses, which was not only cumbersome to design and wire, but also resulted in numerous short circuits and wiring faults. With the advent of automated laser drilling machines, thousands of holes per board can be drilled quickly without the need for point-to-point wiring.

Vias can go through all layers of a board, or they can go only between certain layers and not through the entire stackup (blind vias). As signals move horizontally through copper traces, and vertically through different layers through vias

There are three ways to drill a board:

1. Through holes

These connect all of the alternating layers of the board. This means that the top and bottom layers, as well as the middle layers, are fully drilled.

2. Buried Vias

They connect the internal layers in a multi-layer printed circuit board. These drilled holes only connect the inner layers and never the outer surfaces.

3. Blind Vias

Finally, they connect the top and bottom layers of the board to the internal layers, but do not penetrate the entire board.

Drilling Challenges

The challenge with through-hole drilling is that the laser must drill through the first layer without damaging the layers below. This is why automatic computer-aided drilling is so popular in PCB design. Because our laser machines work directly from CAD data, you can rest assured that the results will be accurate.

Although laser via drilling has a lower drilling speed compared to traditional mechanical drilling options, it has several advantages, namely that it can drill holes in circuits with dense designs, and it allows printed circuit boards to be stacked in multiple layers, reducing the need for a large single layer.

In addition, the laser can be controlled in a precise manner so that it does not touch the internal copper layers. Finally, when a laser is used for via drilling, the positional accuracy of the laser, as well as the positioning accuracy of the hole, is significantly better than other forms of traditional mechanical drilling.

For those interested in drilling lasers, the UV laser can drill up to 200 holes per second, while the UV laser can drill up to 80 holes per second. Typically, companies will use the UV laser combination because it offers high flexibility in opening the copper surface of the board while maintaining a high drilling speed.