HDI PCB
Highly integrated, Ultra-thin, High-performance

• Blind Vias: Connect outer and inner layers (no full penetration) – visible from the surface.
• Buried Vias: Connect inner layers only (invisible) – save outer space.
• Through-Hole Vias: Penetrate all layers – common but less space-efficient.

In simple terms, the difference between the three lies in whether they penetrate the entire board thickness and the layers they connect. Blind and buried vias are key technologies for achieving high-density interconnection (HDI).

Any-level interconnection represents the top level of HDI technology, allowing direct interconnection between any two layers of the PCB through laser microvias. It eliminates the concept of a "core board" and usually requires multiple laser drilling and lamination processes, enabling the highest routing density and flexibility. It is mainly used in extremely complex chip packaging and high-end electronic products (e.g., motherboards of high-end smartphones).

It is recommended to use blind/buried vias if your design faces the following issues:

• High routing density, making circuit crosstalk difficult to avoid with ordinary through-hole vias;
• Requirement to reduce PCB area by more than 30%;
• Signal transmission ≥10Gbps (e.g., 5G modules)

Contact our engineers for free design evaluation to determine the best solution for your specific application.

Relying on a digital production management system, PCBMASTER can achieve fast delivery of blind/buried via PCBs:

• 7 days for 4-layer and 1level-HDI PCB prototypes
• 10 days for mass production

You can contact PCBMASTER service specialists at any time if you have expedited needs.

Yes, usually. The reasons are:

• Complex Process: Additional steps such as laser drilling, multiple laminations and electroplating hole-filling are added.
• Material Cost: Special materials (e.g., RCC) may be required.
• Yield Challenge: More complex processes pose a test for manufacturing yield.

However, blind/buried via technology can optimize the overall system cost by reducing the total number of layers or achieving product miniaturization and high performance. PCBMASTER is committed to providing you with the most cost-effective solutions through mature processes and efficient management.

Currently, PCBMASTER can stably mass-produce 1level to 3level blind/buried via PCBs, covering mainstream scenarios such as consumer electronics and industrial control. For high-order requirements (e.g., Any-level), customized solutions can be provided to support customers throughout the entire process from design to mass production.

PCBMASTER implements strict full-process quality and process control, strictly controlling laser parameters, electroplated copper thickness and lamination processes.

Multiple testing methods:

• AOI (Automated Optical Inspection): Checks for circuit and via position defects.
• Four-Wire Low-Resistance Test: Checks for hidden defects such as cold solder joints and thin hole copper, ensuring current transmission reliability.
• X-Ray Inspection: Checks via alignment, internal structure and hole-filling quality.
• Impedance Test: Ensures the impedance of high-speed signals is controlled within the required range (e.g., tolerance ±5%).
• Reliability Tests: Thermal cycle tests, random vibration tests, etc., can be conducted to ensure product reliability in harsh environments.