Are Microvias Used in IC Packaging?


Microvias Used in IC Packaging

In modern electronic devices, it’s important to pack the most functionality into as small a space as possible. Printed circuit boards (PCBs) are the foundation for this effort, as they provide a platform on which to mount components and route signals. While it is possible to create powerful systems using a variety of PCB formats, the trend is towards smaller and more portable devices. To achieve this goal, high-density interconnects (HDI) have become increasingly popular. These features offer more connections to a board’s layers, allowing for greater functionality in compact design packages.

HDI technology relies on microvias to connect between layers in a multilayer PCB. Microvias are much smaller than traditional through-hole vias, allowing them to fit within tight spaces between components and traces. This allows designers to connect components and traces with much more precision, which in turn enables them to achieve higher speeds and lower power requirements than conventional PCBs.

The use of microvias also helps to increase the density of a PCB’s layers, allowing it to support more complex and feature-rich devices in a smaller package. The density gains made possible by microvias are especially important as the pin pitch on packaged devices continues to shrink. As a result, it is no longer possible to reliably connect these packages to PCBs using conventional via diameters and line widths.

Are Microvias Used in IC Packaging?

To address this challenge, manufacturers have adopted a number of techniques to ensure that devices can be connected to PCBs using high-density interconnects. In addition to the use of microvias, these technologies include copper foil overlays and fine-pitch traces. The use of these methods helps to maintain proper impedance and minimize EMI, which is typically caused by signal reflections in conventional via holes.

While these technologies help to increase the density of a PCB, they do not automatically guarantee reliability. To ensure that the boards can perform as expected, engineers must carefully consider the design and fabrication process. This includes the use of standards and specifications that govern microvia construction, testing, and performance. These standards, which are developed by industry organizations like the Institute of Printed Circuits (IPC), are critical for ensuring that a board can withstand the rigors of manufacturing and operating conditions.

The most critical factors that impact microvia integrity are the size, shape, and filling of these small features. The materials used in the conductive filling of the microvias must be chosen for their electrical and thermal properties, which are essential for handling current loads and dissipating heat effectively. Additionally, the size and depth of the vias must be carefully considered to avoid causing problems such as shorting out or leaking solder.

Several methods are available to construct microvias, including plasma etching and laser drilling. The latter method is particularly important for constructing HDI PCBs because it can be used to form multiple vias in the same layer. This can reduce the overall complexity of the board, which translates to cost savings for manufacturers and consumers alike.

Leave a Reply

Your email address will not be published. Required fields are marked *