HDI PCB

HDI PCB Manufacturing | More routing freedom. Built around your design.

Reliable HDI PCB manufacturing with microvias, blind/buried vias, and fine lines. Ideal for smartphones, medical devices & aerospace electronics.

At China 365PCB, we specialize in HDI PCB (High-Density Interconnect Printed Circuit Boards), engineered for superior performance in compact, high-speed applications. Our HDI PCB boards feature laser-drilled microvias, blind & buried vias, and ultra-fine lines/spacing, making them ideal for next-gen electronics.

From prototypes to production, we help you align the stackup, via structure and fabrication requirements with your component layout.

Minimum trace / space: 50 / 50 µm
Laser microvia diameter: 0.10 mm
Controlled impedance tolerance: ±10%
Minimum order quantity: 1 piece

What Is an HDI PCB?

An HDI PCB board uses high-density interconnect technology to fit more electrical connections into a limited area. Fine traces, small connection pads and microvias help route signals from closely spaced components to the layers where they are needed.

HDI printed circuit boards are useful when conventional through-hole routing leaves too little room for component escape routing. HDI PCB technology can also shorten selected interconnections, while signal performance still depends on materials, reference planes, routing and the complete channel design.

We combine HDI fabrication with PCB assembly services for projects that need populated boards.

Does your board need HDI?

Start with component pitch, pin count, available board area and the required routing paths.

If a conventional multilayer PCB meets those requirements, extra build-up stages may add unnecessary cost. If routing is constrained, review the HDI stackup before completing the layout.

HDI PCB Fabrication Specifications

Use the following capabilities to start your project review. Share the actual layer connections, copper requirements and component pitch so we can confirm a manufacturable combination.

Feature	Capability / option	What to specify
Trace width / spacing	Down to 50 / 50 µm Approximately 2 / 2 mil	Minimum features by layer and copper weight; allow manufacturing margin where the layout permits.
Laser microvia diameter	Down to 0.10 mm	Via depth, start/end layers, capture pads and registration requirements. Diameter alone does not define the usable structure.
Layer count	Up to 16 layers; higher counts on review	Total layers, board thickness, material system and the number of build-up layers on each side.
Sequential build-up	Structures up to 3+N+3	Complete stackup and via map. Stacked microvias, staggered microvias and the number of lamination stages need separate review.
Interconnections	Laser microvias; blind and buried vias	Identify each via type and its layer span in the drill data and fabrication drawing.
Via filling / via-in-pad	Resin plugging; via-in-pad options	Specify filling, capping and planarity requirements. Copper-filled microvia requirements need explicit process confirmation.
Controlled impedance	±10% tolerance	Target impedance, single-ended or differential structures, reference layers and required verification records.
Acceptance requirements	IPC Class 2 / Class 3 project requirements	Agree the applicable standard, revision, class and inspection plan in the order documentation.
Minimum order	1 piece	Prototype quantity and anticipated production demand; tooling and engineering costs may apply.

Minimum line width, microvia diameter and maximum layer count are individual capability limits. They are not automatically available together in every construction.

Select the HDI Stackup Around the Routing Requirement

In common build-up notation, N represents the number of copper layers in the central conventional board section. The numbers on either side describe added build-up layers. The layer notation does not specify whether the microvias are stacked or staggered.

1+N+1

One build-up layer per side

A starting option when one additional routing transition on each side provides sufficient component escape routing.

Review: the BGA fanout, target pads and available routing area before adding complexity.

2+N+2

Two build-up layers per side

Adds routing options across more layers for layouts that cannot be completed with a simpler structure.

Review: via arrangement, registration, dielectric thickness and additional process stages.

3+N+3

More demanding interconnection

For advanced HDI PCB projects where the component layout requires further build-up layers.

Review: the exact via interfaces, assembly heat exposure and the qualification plan for the proposed construction.

For example, a 1+4+1 construction has six copper layers. Two boards with the same total layer count can still need different fabrication routes because their via connections differ. See our sequential lamination PCB process for more on build-up manufacturing.

Stacked and staggered microvias

Staggered microvias are offset between successive dielectric layers and connect through an intermediate copper feature. They use more lateral space.

Stacked microvias align vertically. They conserve routing space but make the integrity of the filled via and its interfaces especially important.

We review the proposed arrangement with the build-up structure and reliability requirements. A 3+N+3 stackup does not automatically mean three vertically stacked microvias.

Explore microvia PCB technology, blind via PCB construction and buried via interconnections.

Our HDI PCB Fabrication Process

HDI technology in PCB manufacturing combines circuit patterning, layer bonding and precision interconnections. The sequence depends on the approved stackup and which connections must be formed at each stage.

Engineering release

Review the manufacturing files, material system, build-up structure, via treatment and acceptance requirements. Resolve open questions before tooling.

Core circuitry and inner-layer checks

Form the core circuitry and the specified internal connections. Check the features that will become inaccessible after lamination.

Build-up lamination and laser drilling

Add the specified dielectric and copper layers. Form the laser microvias for the layer pairs in that build-up stage.

Metallization and via treatment

Prepare and metallize the via surfaces, then apply the agreed filling or capping process where required. Repeat build-up operations for additional stages.

Outer layers, solder mask and finish

Complete outer-layer features, solder-mask openings, pad finish and board profile against the released fabrication data.

Inspection, testing and delivery

Complete the agreed inspections and electrical tests. Supply bare boards or continue into component assembly and its separate test plan.

Learn more about laser-drilled PCB manufacturing and BGA, QFN and fine-pitch PCB assembly.

Where HDI Circuit Boards Fit

Select HDI technology when component density, packaging or interconnect requirements justify the construction. Qualification requirements depend on the finished product and its operating environment.

Smartphones and tablets

Dense component layouts and compact internal modules where fanout and board area drive the stackup.

Consumer electronics PCB manufacturing

Wearables and connected devices

Compact sensing and communication modules that need coordinated component placement and interconnections.

IoT and edge-device assembly

Medical equipment

Space-constrained monitoring and diagnostic electronics with clearly defined material, traceability and validation requirements.

Medical PCB project requirements

High-speed networking

High-pin-count devices and dense signal routing, with impedance, loss and return-path requirements assessed together.

High-speed PCB manufacturing

Aerospace control modules

Compact electronic assemblies where the interconnect structure needs an application-specific acceptance and qualification plan.

Aerospace PCB requirements

Flex and rigid-flex projects

An HDI flex PCB or HDI rigid-flex PCB combines dense interconnections with a flexible construction. Send the rigid and flexible layer requirements for a separate feasibility review.

Flexible PCB manufacturing
Rigid-flex PCB manufacturing

HDI PCB Cost, Lead Time and MOQ

HDI PCB cost depends on more than finished board size. Build-up stages, material utilization, microvia construction and acceptance requirements all affect the manufacturing route.

Stackup complexity: Layer count, lamination stages, material system and finished thickness.
Via and fine-line features: Layer-pair connections, stacked or staggered arrangements, via-in-pad treatment and feature density.
Quantity and panel use: Order quantity, tooling, board outline, panel utilization and planned repeat orders.
Testing and delivery: Inspection records, qualification work, assembly scope and requested schedule.

To compare quotes, use the same drawing revision, stackup, via treatment, finish, quantity and inspection scope. Ask for tooling, bare-board fabrication, assembly and delivery charges to be identified separately.

From the first board to repeat production

MOQ: 1 piece.
Prototype reference: 5–7 working days.
Production reference: 10–14 days.

These are planning estimates. Your quotation confirms the production schedule and delivery date after file approval, material availability and testing requirements are reviewed. Transit time is quoted separately.

For an urgent build, send complete files and the required delivery date so we can assess an expedited schedule.

Technical Capabilities & Certifications

• Min Trace/Space: 50/50μm

• Laser-drilled Microvias: ≤ 0.1mm

• Layer Count: Up to 16+

• Via Filling: Resin Plugging

• Impedance Control ±10%

• IPC Class 2 & 3 compliance

• ISO 9001, ISO 13485, UL certified

These advanced HDI features are made possible by our specialized PCB manufacturing capabilities, ensuring precision and reliability for compact, high-speed designs.