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HIGH-DENSITY INTERCONNECT
HDI PCBManufacturing
SLLPCB is an HDI PCB manufacturer with its own production facilities. We provide HDI PCB fabrication, engineering support, and production services for complex high-density PCB designs.
Engineering prototypes · Production projects
HDI PCB samples · Original product photography
01 · OVERVIEW
What Is
HDI PCB?
An HDI PCB is a high-density interconnect printed circuit board. It uses small interconnect features, such as laser-drilled microvias and fine traces, to fit more connections into a limited area.
HDI boards can combine blind microvias, buried vias and plated through-hole vias. Their construction often uses buildup layers around a multilayer core. The right structure depends on package escape routing, the board outline and the layers each connection needs to reach.
SLLPCB manufactures HDI PCBs in its own production facilities, supporting engineering prototypes, small-batch orders, and volume production. Our engineering team reviews HDI structures, materials, and manufacturing requirements before fabrication. Share the design constraints early so the proposed construction can be reviewed before fabrication.
02 · DESIGN ADVANTAGES
HDI PCB Advantages
More Routing Space Around Dense Packages
Microvias and smaller capture pads can open routing channels around dense BGA and other compact packages. This helps when conventional via geometry blocks the required escape paths.
Smaller Board Outlines
HDI can make a compact layout possible when the enclosure leaves little room for a larger board. The benefit comes from fitting the required connections within the allowed area.
More Control Over Vertical Connections
Selected via spans can reduce unused via sections and provide more direct access to routing layers. Electrical performance still depends on the full channel, including materials, trace geometry and reference-plane connections.
Opportunities to Simplify the Product
A feasible HDI layout may reduce board area, layer count or the need for connections between separate boards. Compare complete designs before claiming a saving. Added buildup operations, filling requirements and validation can also affect total cost.
03 · INTERCONNECT ARCHITECTURE
HDI PCB Structures
HDI PCB structures provide different options for layer connections and routing. Common designs include 1+N+1, 2+N+2, 3+N+3 and any-layer HDI. The right structure depends on package escape, board size, signal requirements and manufacturing feasibility. Choose the simplest structure that meets your design needs to avoid unnecessary complexity and cost.
1+N+1
2+N+2
3+N+3
Any-layer
04 · TECHNICAL REFERENCE
HDI PCB Manufacturing
Capabilities
These capabilities vary by HDI structure and process requirements and may not all apply to the same board. Submit your stackup and fabrication files for a project-specific review.
| Feature | Capability |
|---|---|
| Layer Count | 2–68 layers |
| HDI Structures | Up to 9 + N + 9; any-layer HDI |
| Finished Board Thickness | 0.1–14 mm |
| Minimum Outer-Layer Trace / Space | 50 / 50 µm |
| Minimum laser hole diameter | 100 µm |
| Maximum Laser Via Aspect Ratio | Up to 1:1 |
| HDI build-up | 9 + N + 9 |
| Copper-Filled Laser Vias | Laser via minimum diameter: 100 µm |
| Laser Via Capture / Landing Pad | 0.20 mm |
| Maximum Dimple After Copper Filling | ≤15 µm |
| Minimum mechanical hole diameter | 0.15 mm |
| Controlled Impedance Tolerance | ±5% |
| Surface Finishes | ENIG, ENEPIG, OSP, immersion silver and immersion tin |
05 · EQUIPMENT
Equipment
Laser Drilling Equipment
Precision laser drilling creates microvias as small as 100 μm, connecting adjacent PCB layers without taking up extra routing space. It supports fine-pitch BGA layouts and high-density HDI designs.
Vacuum Lamination Equipment
Controlled heat and pressure bond multiple PCB layers together. Sequential lamination supports complex HDI stackups, including 1+N+1, 2+N+2, 3+N+3, and higher-order structures.
Laser Direct Imaging (LDI)
LDI transfers circuit patterns directly onto photoresist with high accuracy. It supports fine lines and spaces down to 50/50 μm, helping fit more connections into limited board space.
Copper Via Filling Plating Equipment
Specialized copper plating fills laser-drilled microvias to create reliable electrical connections between layers. Properly filled vias also support stacked microvias and via-in-pad structures used in advanced HDI boards.
X-Ray Registration Equipment
X-ray registration locates internal layer targets after lamination. It helps maintain drilling accuracy and layer-to-layer alignment, especially in HDI boards that require multiple lamination cycles.
Automated Optical Inspection (AOI)
AOI scans high-density circuit patterns for shorts, opens, missing copper, and other defects. Early inspection helps identify problems before additional layers are laminated, reducing the risk of hidden defects.
Can You Review a Design Before the Stackup Is Final?
Yes. Provide the proposed layer count, package details, fixed board dimensions and known routing constraints. Identify which requirements can change. A preliminary assessment is a starting point; fabrication needs an approved stackup and complete manufacturing data.
What Should I Include in an HDI PCB RFQ?
Send the current Gerber or ODB++ data, drill information, stackup and via spans. Add the material, copper, finish, quantity, impedance and acceptance requirements. Include the target delivery date and destination. BOM and placement data are needed when assembly is part of the request.
Does Every Dense PCB Need Any-Layer HDI?
No. A conventional multilayer or simpler HDI structure may provide enough routing space. Select any-layer construction when the required interconnections justify it, after checking the actual package escape layout and fabrication rules.
What Affects HDI PCB Pricing and Lead Time?
The buildup sequence, via filling, materials, geometry, quantity and test scope all matter. Confirm material availability and the point at which manufacturing data will be approved. Shipping time should be separated from fabrication time when planning arrival.
Can the Prototype Construction Be Used for Production?
It can provide a starting point when the construction and process are suitable for production. Changes to material, stackup, via geometry or the production route may require another review. Agree on the evidence needed before moving to the next order stage.
Which Inspection Records Should Be Specified?
Define the records required by the board specification and application. These may include electrical test results, dimensional checks, microsections or impedance records. Reliability qualification is a separate requirement and should be agreed for the actual construction.
Send your design files and project requirements to discuss an HDI PCB quote. If the design is still being developed, include the constraints and decisions that remain open.
Talk to our sales.
Send your design files and project requirements to discuss an HDI PCB quote.
