high density interconnects more expensive
High density interconnect is a specialized PCB technology that allows more functionality and features to be packed into the same footprint of a traditional circuit board. This technology has become increasingly popular in the manufacturing of mobile phones, tablets and other highly complex consumer electronics. It can also be found in telecommunications infrastructure and industrial control panels where space to route signals is a premium. This advanced technology uses a combination of blind and buried microvias, laser formed to connect the complex circuitry on all layers of the PCB. This makes them smaller in size than multi-layer and double-sided PCBs and offers superior signal transmission.
As semiconductors continue to shrink, reducing their rise-time and increasing the number of leads in a given footprint, the need for denser circuitry continues to grow. The increased component count on a single PCB requires lower trace dimensions, narrower gap sizes and smaller vias. This can push conventional constructions to their limits where the addition of additional layer counts and small traces and vias can make it difficult to implement impedance-controlled routing calculations.
The solution to these challenges is to utilize a technique called high density interconnect printed circuit boards. These boards offer higher trace and via density than standard PCBs by using smaller traces, shorter gaps and more microvias in the inner layers. In order to take advantage of this technology, the PCB manufacturer must be able to provide both the design and manufacturing processes required to support the higher trace and via density.
Are high density interconnects more expensive than rigid ones?
These PCBs are more expensive than standard multi-layer and double-sided PCBs, but they can be cost-effective in the long run as they reduce the number of PCBs used in a final product. They also reduce the weight and volume of the final product, allowing manufacturers to create more compact and portable devices with enhanced performance.
The HDI design structure of the 1+N+1 and 2+N+2 PCBs differs in that they have different types of microvias. This enables the use of the appropriate stack-up configuration for a given device design and ensures that the circuitry is properly implemented. Getting started with HDI PCBs requires a well-planned stack-up configuration. Getting this right is essential to the proper implementation of the design to minimize impedance-controlled routing issues and improve signal integrity performance.
In order to be effective, the HDI PCB design must account for the proper placement of all the components, the number and type of through-holes, and the placement of the copper-filled buried microvias. Taking the time to correctly plan these elements in the layout will result in a successful and cost-effective end product.
The process of creating a high-density interconnect PCB is a specialized one that requires more steps than the standard fabrication process. This includes the use of a special surface finish that is applied to prevent electrical shorts between adjacent components, precision hole drilling with lasers for the microvias, lamination with insulating materials, etching and copper plating for the desired circuit patterns, application of a solder mask and finally assembly using automated techniques. This specialized process prioritizes the use of fine-pitch components and tightly stacked layers, and it requires rigorous testing and quality control in order to produce reliable and functional HDI PCBs.
