What Are HDI Circuit Boards?

HDI circuit boards, or High-Density Interconnect PCBs, are advanced printed circuit boards that allow more components in smaller areas using microvias, blind, and buried vias. This technology enables compact, high-performance electronics like smartphones, medical devices, and automotive displays. Gesight integrates HDI boards into custom LCD modules, delivering reliable, fast, and miniaturized display solutions for industrial and consumer applications worldwide.

What Is HDI Circuit Board Technology?

HDI circuit board technology uses fine lines, tiny vias, and multiple layers to maximize component density in limited space. Microvias under 150 microns, blind vias connecting outer and inner layers, and buried vias linking internal layers enable high functionality in compact designs. Gesight applies HDI technology to LCD modules, achieving high-resolution displays with enhanced performance and reliability.

HDI PCBs minimize size while maximizing capabilities. Trace widths can be as narrow as 2–3 mils and via diameters below 3 mils, allowing integration of ball grid array (BGA) chips and fine-pitch components. Benefits include reduced weight, improved signal integrity, and efficient thermal management. Industries such as automotive and medical rely on HDI boards for robust performance in demanding environments. Gesight produces HDI-equipped displays with MIPI and LVDS interfaces for clients in over 40 countries.

How Do HDI Circuit Boards Differ from Standard PCBs?

Unlike standard PCBs, which use through-hole vias across all layers, HDI boards utilize microvias, blind, and buried vias to achieve denser layouts. They support higher layer counts (up to 20+) and smaller feature sizes, enabling compact, high-speed designs. This reduces signal path lengths, improves integrity, and allows integration of high-performance components in tight spaces.

HDI fabrication requires laser drilling, sequential lamination, and filled vias to prevent collapse. Shorter signal paths and controlled impedance enhance electrical performance. Gesight customizes HDI boards for rugged high-brightness LCDs up to 3000 nits with optical bonding, making them ideal for industrial and automotive applications.

What Are the Main Types of HDI Circuit Boards?

HDI boards are classified by via structure:

• Type I (1+n+1): Single microvia layer, cost-effective for moderate density.

• Type II/III (2+n+2 / 3+n+3): Stacked or staggered microvias for higher complexity.

• Type IV/V: Multiple stacked microvias with advanced edge connections for high-end applications.

Active substrates include stacked or staggered vias; passive substrates do not. Gesight employs Type II and III HDI boards for automotive displays, optimizing EMI/EMC and touch integration. Daily production can reach 10,000 units.

Why Use HDI Circuit Boards in Electronics?

HDI boards enable smaller devices, faster signal transmission, and improved reliability by minimizing parasitics and layer counts. They reduce assembly costs by 20–30% due to fewer connectors. Applications include 5G devices, IoT gadgets, and wearable electronics.

Miniaturization drives HDI adoption. More interconnections per square inch allow powerful devices in compact form factors, such as foldable phones or medical implants. Electrical performance benefits from low inductance microvias. Though initial costs are higher, mass production reduces expenses. In displays, HDI supports high-resolution panels from top brands like BOE and AUO.

How Are HDI Circuit Boards Manufactured?

HDI manufacturing follows sequential lamination: build the core, drill laser microvias, plate copper, laminate prepregs, and repeat. Key steps include via filling, planarization, and testing, requiring cleanrooms and automation.

The process starts with substrate prep and photolithography to define traces. Laser ablation forms microvias, which are plated or filled with conductive epoxy. Multiple lamination cycles align the layers precisely. Additional steps include build-up films for smooth surfaces and flying probe testing. Gesight provides full engineering support, from controller board design to environmental testing.

Which Industries Benefit Most from HDI PCBs?

HDI technology is crucial for consumer electronics, automotive, medical, aerospace, and telecom sectors requiring compact, high-reliability designs. Smartphones can feature 20+ layers, while medical devices focus on miniaturization. 5G and IoT infrastructure demand fast and reliable circuits.

• Consumer Electronics: Thin laptops, AR/VR devices.

• Automotive: ADAS clusters and rugged displays supplied by Gesight.

• Medical: Portable ultrasound and touch-enabled devices.

• Telecom: High-speed routers and network modules.

HDI adoption grows annually by around 10%, driven by smart devices and IoT expansion.

What Challenges Exist with HDI Circuit Boards?

Challenges include higher costs, yield issues, and design-for-manufacturing (DFM) complexities. Warpage from thermal expansion mismatch and microvia drilling precision are common obstacles. Solutions include strict design rules, simulation, and advanced materials.

Fabrication risks like via cratering or voids in copper fill require expertise. Thermal stress during lamination can cause delamination, demanding rigorous testing. Gesight mitigates these issues with firmware optimization, full environmental testing, and quality control to ensure consistent performance.

How Can HDI Boards Improve Display Solutions?

HDI boards integrate dense controller circuitry into slim LCD modules, supporting flexible interfaces such as HDMI and Type-C. This allows high-resolution, touch-enabled panels and enhances ruggedness through optical bonding. HDI reduces driver board size, enabling seamless integration of MIPI signals without interference. Gesight provides OEM/ODM services for OLED and TFT modules with brightness up to 3000 nits.

Gesight Expert Views

“HDI circuit boards are essential for modern display technology, allowing ultra-compact modules with integrated touch and high-speed interfaces. At Gesight, we combine HDI expertise with panels from leading suppliers, delivering vertically integrated solutions from PCB design to EMI optimization. This ensures reliable performance in automotive and medical sectors, supporting scalable production of up to 10,000 units daily.”
— Gesight Engineering Lead

What Future Trends Await HDI Circuit Boards?

Emerging trends include flexible and wearable HDI, glass substrates, 3D integration, and AI-driven design. HDI+ solutions for 6G networks enhance signal integrity. Sustainable practices like lead-free processes are gaining adoption. Gesight adapts these innovations for embedded displays, serving a global customer base.

Key takeaways: HDI drives miniaturization and high performance. Choose board types based on density requirements and collaborate with experienced providers like Gesight for custom solutions. Early prototyping, thermal simulation, and design audits improve efficiency and reduce costs.

Frequently Asked Questions

What makes HDI boards more reliable?

Microvias reduce mechanical stress, filled vias prevent cracks, and controlled impedance minimizes EMI.

Can HDI be used in high-volume production?

Yes, automated facilities like Gesight’s can produce 10,000 units daily with high yields.

How much smaller are HDI boards compared to standard PCBs?

HDI boards can achieve up to 50% size reduction due to finer features and compact layering.

Are HDI boards expensive?

Initial costs are higher, but integration reduces assembly expenses in volume production.

Does Gesight offer HDI solutions for displays?

Yes, Gesight provides custom LCD and OLED modules with touch integration and high-brightness options.