Can Micro Vias Be Used
The use of micro vias on a printed circuit board (PCB) increases manufacturing efficiency and reduces electromagnetic interference (EMI). However, the technology poses reliability challenges that require careful design considerations. Microvias are small holes that allow copper to connect circuit layers on a PCB. They are used to provide access for components and traces that may be too large for standard through-holes. There are several types of microvias, including buried and blind microvias, and they can be stacked or staggered to create connections across multiple layers. Regardless of type, microvias must be filled with either pure copper or epoxy and copper resin to ensure strong, reliable connections between layers.
A micro vias is a small hole that allows copper to connect circuit layers on a printed circuit board (PCB). They are used to provide access for components and trace lines that may be too large for through-holes. Microvias are available in a wide range of diameters, from 12 mil (0.15 mm) to 10 mil (0.25 mm). In order to be considered a microvia, the size must be smaller than the target pad and capture pad on the PCB.
Using a laser beam, manufacturers can create a series of circular holes on the surface layer of a circuit board that will eventually form a microvia. The process can also be used to create a variety of other shapes, such as triangles and hexagons. Although they are less common than traditional through-holes, microvias have a number of advantages over through-holes, including reduced cost, increased efficiency and improved signal integrity. They also help to increase the yield of a printed circuit board by decreasing assembly and test time.
Can Micro Vias Be Used in Power Converters?
Unlike through-holes, which are typically located on the top surface of a printed circuit board (PCB), microvias are buried within the board and can only be accessed through solder joints or other interconnects on the circuit board. They are therefore a good option for applications where space is limited, such as embedded processors and high-speed memory chips.
The advantage of using microvias is that they can be placed closer together than through-holes, making it easier for components and traces to reach them. This is especially important in high-speed applications, where the presence of EMI can cause unwanted interference and degrade performance.
However, the low aspect ratio that is required by IPC standards for microvias can cause reliability issues if not carefully managed. Specifically, microvias with an aspect ratio of greater than 1 can be susceptible to stress fracture at the via neck, due to the way that copper curves inward during the plating process.
The best way to avoid this issue is to keep the aspect ratio of a microvia low, and to make sure that it spans only one or two interior layers of the PCB. This will minimize the stress that is placed on the metallization and inner copper layer, which can lead to interconnect defects (ICDs). The most common types of ICDs associated with microvias include copper bond failures, debris-based ICDs and voiding-based ICDs.
