Can Microvias PCB Be Used in Medical Devices?

Microvias PCB Be Used in Medical Devices

When designing a medical PCB, there are many things to consider, including EMI/EMC compliance. This is because electrical signals must remain clear from interference, which can cause damage to the device or affect other devices. Medical PCBs also must be as efficient as possible in terms of power consumption, as they may run off of batteries or other sources. One way to achieve this is by using microvias.

Microvias are small holes drilled in the layers of a circuit board. They can be either blind or buried, and they can be filled with a variety of different materials. Typically, they’re filled with copper, which has the advantage of being both conductive and thermally efficient. Other materials that can be used in a via include gold and non-conductive epoxy.

Compared to traditional through-hole vias, microvias pcb have much smaller diameters ranging from a few microns to a few tenths of a millimeter. They are also more difficult to place and require specialized fabrication techniques. The use of these vias can impact signal integrity in ways that may not always be easily understood.

The size and depth of a microvia determines its aspect ratio. Traditionally, the Institute of Printed Circuit Boards (IPC) defined a microvia as any hole with a 1:1 aspect ratio that doesn’t exceed a 0.010-inch depth. This threshold was chosen to make it easier for manufacturers to use the technology. However, as lasers became more advanced, it was possible to drill holes of a much smaller diameter, so the IPC decided to change its definition to reflect this.

Can Microvias PCB Be Used in Medical Devices?

To create a via, the manufacturer must first pre-drill the substrate material. Then, a high-powered laser is used to drill the hole. The size of the resulting hole will depend on the laser’s power and the thickness of the layer.

After drilling, the manufacturer can either fill the microvia with pure copper or epoxy resin and copper. The latter option is preferred, as it offers a higher level of reliability. When using pure copper, voids can form that decrease the lifespan of the via. These voids are known as interconnect defects (ICD).

If the fabricated circuit board is to be used in a medical setting, the vias must be filled with copper rather than non-conductive epoxy. This is because copper has better thermal and electromagnetic properties, which can help protect the underlying layers of the circuit board. The presence of a copper fill also helps the vias stay cool and resist corrosion.

Other factors can impact the durability of a PCB, such as its manufacturing process and design. For example, some ICDs are debris-based, resulting from contaminants that get trapped in the plating or inner copper layer of a microvia. Other ICDs are caused by a high amount of stress during assembly or usage, causing the copper connection to physically break off. In these cases, the ICDs are known as copper bond failure ICDs. These types of ICDs can be difficult to detect, as they often work properly during testing and assembly but reveal problems during actual use or in the field.