APTPCB HDI PCB Manufacturing Services

APTPCB provides complete HDI (High-Density Interconnect) PCB manufacturing solutions from light to complex multilayer structures. Our HDI boards are engineered with microvias, fine lines, and sequential lamination to achieve compact, high-performance interconnections for advanced electronics such as smartphones, RF modules, and industrial control systems.

HDI PCB Types We Offer

HDI PCB stack-ups are categorized by the number of sequential buildup (SBU) layers added to the core. The notation X + N + X indicates buildup layers on each side (X) and core layers (N). APTPCB supports all HDI configurations for different density and reliability requirements.

• 1 + N + 1 (Type I HDI) – One buildup layer on each side, single-layer microvias. Ideal for moderate I/O density designs and cost-sensitive applications.
• 2 + N + 2 (Type II HDI) – Two buildup layers per side, combining microvias and buried vias. Provides higher routing density for fine-pitch BGAs.
• 3 + N + 3 (Type III HDI) – Three or more buildup layers per side with stacked microvias. Used in high-end mobile, RF, and computing products.
• Mixed or Asymmetric Structures (e.g., 1 + N + 2, 2 + N + 3) – Customized hybrid stack-ups for specific design and signal integrity needs.

Via and Interconnect Structures

• Through-Hole Via: Traditional via passing through the entire PCB, economical for simple interconnections.
• Blind Via: Connects an outer layer to one or more inner layers, saving routing space.
• Buried Via: Located between internal layers, invisible on the outer surface.
• Microvia: Laser-drilled via (≤0.25 mm) used for HDI layer-to-layer interconnection.
• Via-in-Pad: Microvia placed within component pads, filled and capped to ensure flat soldering surfaces.
• Stacked Microvia: Vertically aligned vias offering ultra-high density for compact BGA designs.
• Staggered Microvia: Offset vias between layers, improving yield and mechanical reliability.

Typical HDI Stack-Up Examples

• 6-Layer (1 + 4 + 1): Single buildup on each side, microvias between outer and adjacent layers; suitable for 0.65 mm BGA pitch designs.
• 8-Layer (2 + 4 + 2): Dual buildup per side, microvia-to-buried via connections for 0.5 mm pitch BGAs.
• 10-Layer or More (3 + N + 3): Three or more buildup layers with stacked microvias; used in high-density computing, RF, and advanced SoC applications.

Material and Design Guidelines

HDI PCBs use ultra-thin cores and prepregs (30–150 µm) to achieve low-aspect-ratio microvias. Typical copper thickness is 18–35 µm. For high-speed or RF designs, APTPCB supports low-loss materials such as Panasonic Megtron, Isola I-Speed, and Rogers laminates. All materials feature high Tg and low CTE for thermal reliability during sequential lamination.

• Microvia diameter: 0.1–0.25 mm, aspect ratio ≤ 1:1.
• Minimum trace/space: 3/3 mil or finer depending on capability.
• Impedance tolerance: ±5% with controlled dielectric thickness.
• Via-in-pad structures: Filled and capped for solderability and reliability.

Reliability and Quality Assurance

APTPCB performs 100% electrical testing, X-ray inspection, and micro-section analysis to ensure plating integrity and via reliability. Staggered microvia structures are preferred for enhanced thermal cycling endurance. Each HDI PCB undergoes reflow simulation and impedance verification before mass production.

Cost and Application Recommendations

• 1 + N + 1: Economical solution for compact consumer electronics.
• 2 + N + 2: Balanced choice for mobile, IoT, and wireless modules.
• 3 + N + 3: Premium structure for advanced communication and computing systems.