How to Choose HDI PCB Material

The choice of material and its construction is pivotal in the design and manufacturing of HDI (High-Density Interconnect) PCBs. The process of designing HDI interconnects entails a comprehension of potential challenges associated with specifying glass reinforced dielectric materials.

Microvia dielectric materials might engender misregistration and rough vias, irrespective of the drilling technique employed—be it plasma, laser, or mechanical. The concerns extend beyond the inherent material properties of the microvia dielectric materials to the consistency of the weave and the caliber of fibers used. The ability to narrow the weave openings by spreading the fibers is crucial, as it diminishes open spaces that can lead to skew and drift.

● Copper Clad Laminate (CCL): Copper clad laminate materials involve the lamination of copper foil to one or both sides of a cured (C-stage) dielectric. The rigid CCLs may be categorized as FR4, FR-5, or certain PTFE types. A typical application employs single-side clad laminate material, where the copper clad serves as the outer layer, and the C-stage is bonded to the sub-composite. Microvias are created using laser drilling techniques. The materials vary based on reinforcement (woven glass, non-woven glass, and expanded PTFE) and the chemistries at play (epoxies, polyimide, polyester, etc.).

● Resin Coated Copper (RCC): Resin coated copper materials consist of copper foil coated with a resin dielectric material, which can be directly bonded to the sub-composite. They are distinguished by their processability in a wet environment or lack thereof. For non-wet processable-coated copper materials, microvias are created using either plasma or laser drilling techniques.

● PP (Prepreg): Often referred to as B-stage, Bonding sheet, or simply Preg, Prepreg comprises fiberglass fabric impregnated with resin. During the Prepreg coating operation, the resin undergoes partial curing without hardening. During the heating phase of the PCB stack-up in the pressing process, the resin in PP will flow, adhere, and bond the PCB core with copper foil or other materials.

Hitech Circuits is a professional HDI PCB manufacturer. If you have the HDI PCB design, you can send the Gerber files to us for a quick quote. Just emai:sales3@hitechpcb.com For more information, you can visit https://hitechcircuits.com/pcb-products/high-density-interconnect-pcb/