The Distinction Between HDI and Regular PCB

5 min read
26 December 2022

A HDI PCB differs significantly from a regular PCB in a number of ways. In order to make an informed choice, you need take care to understand the distinctions. Understanding how the manufacturing process for HDI PCB differs from that of a standard PCB is crucial.

Resin-Coated-Copper (RCC) (RCC)

An innovative dielectric material for PCBs is resin-coated copper (RCC). The multilayer boards that use it serve as their outer layer. This film is offered in a range of copper and dielectric thicknesses.

RCC has the benefits of being lightweight, compatible, and well-compatible with conventional PCB fabrication methods. Additionally, it is a high-performance item that can be used in high-density boards.

The non-flammability of RCC is still another benefit. Additionally, it has a low dielectric constant, making laser engraving possible. It is ideally suited for chip-scale packing due to these characteristics.

Resin-coated copper is typically used in HDI boards. But other materials can also be applied.

Other choices include epoxy liquid and polyimide. These two materials can be laminated together. To prevent the resin from squeezing out during the lamination process, a flow restrictor is typically added to the system for this purpose.

The thickness of the sheet is often decreased. The board's increased density when compared to a standard PCB enables higher processing rates.


A through in pad has become a typical design element when creating a PCB. More components can be added to both sides of the raw PCB thanks to this feature.

Signal path lengths, parasitic inductance, and capacitance are all decreased by this technology. Additionally, it permits smaller board sizes. But the procedure is pricey. Engineers need to have a solid grasp of the fabrication process in order to get the most out of a PCB.

The simplest via in pad is just an electroplated small hole. Other via-in-pad technologies encircle the hole with a ring. They are known as microvias. They typically have a diameter of 0.15 to 0.1 millimetres.

BGA pads and via-in-pads are the most popular pairing. It is frequently more expensive than alternative approaches since they call for a more specialised copper plating procedure.

The annular ring is a crucial component of the via-in-pad design. In essence, the ring encloses the hole and acts as a tolerance for uneven drilling. More accuracy can be achieved during production with a thicker ring.

Process of sequential lamination

A high density interconnect (HDI) PCB must be built using the consecutive lamination method. It enables for additional I/O in compact geometries while reducing the overall number of layers and component size. Many designers have been able to group tiny components closer together by using this technology.

This method also enables the burying of a through and the insertion of dielectric material between the surface copper layers. Despite the fact that this technology is not brand-new, high-density electronic applications have elevated it to the status of one of the most crucial fabrication processes.

The final multilayer PCB is made by pressing and heating the inner and outer layers together during the lamination process. Embedded components are installed after the stack has been constructed. Both passive and active components might be a part of this.

The multilayer board is one of the most popular varieties of board. The major sublayer of the board, known as the core, is located between it and the other layers.

Health Requirements

The market for HDI PCBs is expanding, mostly due to the complexity of mobile devices rising. They provide a high level of performance, flexibility, and durability. These boards are used in touch-screen gadgets, mobile phones, medical equipment, and military electronics.

The quantity of boards required, the length of time required for production, and the overall cost can all be decreased by using HDI technology. It provides better dependability as well.

Particularly in the medical community, the technique has been increasing appeal. For instance, pacemakers demand a small form factor. Vehicles have also utilised HDI circuit boards for better signal retention.

Reduced heat transfer, smaller electrical losses, and improved signal transmission are advantages of HDI technology. Additionally, HDI PCBs are more compact since they contain fewer layers. By reducing the unit's size, the dashboard of the car can be made smaller.

HDI PCBs are utilised in the medical industry to aid in the diagnosis of various disorders. They are especially useful in the healthcare industry, where the demand for computerised equipment is on the rise.


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