Lightwave Communications PCB Board – 6-Layer TU872+RO4350B Hybrid Blind Buried Via PCB

製品の概要

The Lightwave Communications PCB Board is a high-performance 6-layer hybrid blind buried via printed circuit board engineered by UGPCB for optical communication and high-speed digital signal transmission applications. This product features a hybrid stack-up combiningTU872 high-speed digital material とRogers RO4350B high-frequency material. The design merges high-speed digital signal processing capabilities with exceptional RF and microwave signal transmission performance. This PCB serves as an ideal interconnect solution for optical communication ground receiving equipment, high-speed optical transceivers, and base station RF front-end modules.

The プリント基板 industry continues its push toward higher frequencies, faster speeds, and greater density. Single-material solutions can no longer meet the conflicting demands of high-speed digital signals and RF analog signals. UGPCB addresses this challenge through the TU872+RO4350B hybrid design. This 6-layer PCB achieves an optimal balance among signal integrity, 熱管理, そして製造コスト.

製品分類

IPC-6012Eごとリジッドプリント基板の認定および性能仕様, this product falls into the following categories:

Classification Dimension	カテゴリ
Structure Type	Multilayer rigid printed board (6 レイヤー) with blind and buried vias
Material System	Hybrid laminate (high-speed digital material + high-frequency material)
表面仕上げ	エレクトロレスニッケル/浸漬ゴールド (同意する), per IPC-4552
Reliability Class	Meets IPC-6012 Class 2 (dedicated service electronic products) とクラス 3 (高信頼性電子製品) 要件
可燃性評価	UL 94 V-0
Application Domain	Optical communication / telecommunications infrastructure PCB

主要な技術仕様

パラメーター	仕様
レイヤー	6 レイヤー
材料	TU872 (high-speed digital layers) + RO4350B (high-frequency layers)
板厚	1.8 mm
銅の厚さ	35/35/35/35 μm (uniform distribution across all layers)
Smallest Hole Diameter	0.20 mm
表面処理	同意する (2u” gold thickness)
Technical Features	Vacuum plugging + ブラインドビアと埋め込みビア

Key Material Properties

Rogers RO4350B High-Frequency Material (for RF/microwave signal layers):

誘電率 (DK): 3.48 ± 0.05 @ 10 GHz
損失係数 (Df): 0.0037 @ 10 GHz
Z-axis Coefficient of Thermal Expansion (CTE): 32 ppm/°C
可燃性評価: UL 94 V-0
熱伝導率: 0.69 w/(m・K)

TU872 High-Speed Digital Material (for high-speed digital signal layers):

誘電率 (DK): < 3.5 @ 10 GHz
損失係数 (Df): ~0.009 @ 10 GHz
高いガラス転移温度 (TG) with excellent thermal stability and CAF resistance

設計ガイドライン

Hybrid Stack-up Architecture

This 6-layer PCB employs a hybrid stack-up with TU872 and RO4350B materials. The core design principle positionsRO4350B on outer layers or specific signal layers requiring high-frequency RF signal transmission, その間TU872 serves the high-speed digital signal processing layers. This strategic material allocation enables a single PCB to handle both GHz-level RF signals and high-speed digital logic signals, eliminating the performance compromises inherent in single-material solutions.

Blind and Buried Via Design

Blind vias connect outer layers to inner layers without penetrating the entire board thickness. Buried vias reside entirely within the board, invisible from either outer surface. This 6-layer PCB leverages blind and buried via technology to achieve HDI-level routing density.

IPC-6012Eごと, 多層基板 with blind and buried vias must meet stringent plating and fill requirements. The 0.20 mm minimum hole diameter balances manufacturing yield with high-density routing capability. In a 6-layer board, blind vias from the outer layer to inner layers require precise depth control—they must penetrate to the target inner layer without damaging inner-layer circuits, while maintaining sufficient connection area.

Impedance Control Design

The characteristic impedance of signal transmission lines follows this formula (microstrip structure):

$z_{0} = \frac{87}{\sqrt{e_{r} + 1.41}} \ln (\frac{5.98 h}{0.8 w + t})$

どこ $e_{r}$ 誘電率です, $h$ is the dielectric thickness, $w$ トレース幅です, そして $t$ is the copper thickness. RO4350B’s tight Dk tolerance of ±0.05 ensures minimal deviation between designed and fabricated impedance values. This precision proves critical for accurate 50Ω single-ended or 100Ω differential impedance control in optical communication equipment.

Operating Principles

Signal Transmission Principles

高周波数で, PCB signal transmission lines function asdistributed parameter transmission lines. 誘電率 (DK) of the substrate material determines signal propagation velocity:

$v = \frac{c}{\sqrt{e_{e f f}}}$

どこ $c$ is the speed of light in vacuum ( $3 \times 10^{8}$ 3×108 m/s) そして $e_{e f f}$ is the effective dielectric constant. RO4350B’s low Dk value (3.48) enables signal propagation at approximately 54% of the speed of light in vacuum—significantly faster than conventional FR-4 materials (Dk ≈ 4.2-4.8).

Loss Mechanisms

Total signal loss in PCB transmission lines consists ofconductor loss そして誘電損失. Dielectric loss directly correlates with the material’s dissipation factor (Df):

$a_{d} = \frac{π f}{v} de \tan d$

どこ $f$ is signal frequency and $\tan d$ is Df. RO4350B’s Df of just 0.0037 で 10 GHz yields extremely low dielectric loss per unit length. This characteristic proves essential for optical communication signals operating at frequencies above 10 GHz.

Blind and Buried Via Electrical Connections

Blind and buried vias establish vertical interconnections between specific layers within the 6-layer PCB stack-up. Compared to through-hole vias, they significantly reduce parasitic capacitance and inductance effects that degrade high-speed signal integrity. This reduction in parasitic effects has a decisive impact on maintaining signal integrity for high-speed digital and RF signals.

製造工程

Hybrid Laminate Preparation

The TU872 and RO4350B hybrid stack-up represents the core manufacturing challenge for this product. These two materials have different CTE characteristics—RO4350B exhibits a Z-axis CTE of 32 ppm/°C, while TU872 as a modified epoxy system has different thermomechanical properties. UGPCB achieves reliable hybrid interface bonding and strength through precise lamination parameter control (temperature profile, pressure profile, and ramp rate).

Blind and Buried Via Fabrication

Buried Via Formation: Inner-layer cores undergo drilling and copper plating before lamination, encapsulating the buried vias within the board
Blind Via Formation: ラミネート後, controlled-depth drilling from the outer layer targets the specified inner layer with precise depth control

Vacuum Plugging Process

Per IPC-4761 Design Guide for Protection of Printed Board Via Structures, vacuum plugging falls under Via Protection Type VI (complete fill and cover) or Type VII (complete fill) categories. Key process parameters:

プロセスフロー: Drilling → Desmear →Vacuum Plugging → Curing → Grinding
Plug Fill Rate: ≥ 85% (per IPC-6012 requirements)
The vacuum environment eliminates air bubbles from the via holes, ensuring complete resin fill of blind and buried vias

表面仕上げ (同意する)

エレクトロレスニッケル/浸漬ゴールド (同意する, 2u” gold thickness) surface finish complies with IPC-4552 specifications:

Electroless Nickel Layer: 3-6 μm
Immersion Gold Layer: ≥ 0.05 μm (2u” ≈ 0.05 μm)
ENIG provides a flat solderable surface, 優れたはんだ付け性, そして長い保存期間

性能特性

信号の完全性 (そして) 利点

低挿入損失: RO4350B’s low Df (0.0037@10 GHz) minimizes high-frequency signal energy loss during transmission
Low Dielectric Constant Variation: Dk tolerance of only ±0.05 ensures impedance consistency
Stable Electrical Performance: TU872 maintains electrical properties across varying temperature and humidity conditions

Thermal Management Performance

1.8 mm board thickness provides excellent thermal mass and mechanical strength
RO4350B thermal conductivity of 0.69 w/(m・K) effectively dissipates heat
TU872’s high Tg ensures dimensional stability at elevated temperatures

信頼性

Vacuum plugging ensures void-free blind and buried vias, meeting IPC-6012 Class 2/3 要件
Uniform 35 μm copper thickness across all four layers ensures current-carrying capacity and heat dissipation
UL 94 V-0 flammability rating—flame extinguishes within 10 seconds after removal

アプリケーションシナリオ

Ground Receiving Equipment

This represents theprimary target application for this product. Ground receiving equipment must simultaneously process high-frequency RF signals from satellites or microwave links (requiring RO4350B material) and baseband digital signal processing (requiring TU872 material). This 6-layer ハイブリッド基板 precisely addresses this dual requirement.

6-layer lightwave communications PCB satellite ground receiving

Optical Communication Systems

Fiber-optic network transmission equipment
光トランシーバー
Optical amplifiers

High-Speed Digital Communications

5G communication base station RF front-ends
High-speed data switching equipment
Test and measurement instruments

UGPCBを選択する理由?

Mature Hybrid Lamination Technology: Extensive production experience with TU872+RO4350B hybrid stack-ups with controllable yield
Advanced Blind and Buried Via Capability: 0.20 mm minimum hole diameter with vacuum plugging meets HDI interconnection requirements
エンドツーエンドの品質制御: Full-process quality management from material receiving to finished product shipping, strictly per IPC-6012E standards
迅速な応答: Professional engineering team provides DFM (製造可能性のための設計) review support

Inquiry Guidance

To obtain samples, volume pricing, or technical support for the Lightwave Communications PCB Board, please provide:

Gerber files (including stack-up details)
BOM list (if PCBA services are required)
Special performance requirements (impedance values, test specifications, 等)

UGPCB’s team will deliver professional technical evaluation and quotation within 24 時間.

Data Source Declaration

Technical data and standards cited in this document derive from the following authoritative sources:

Rogers Corporation – RO4350B™ Laminate Data Sheet
IPC (エレクトロニクス産業をつなぐ協会) – IPC-6012E リジッドプリント基板の認定および性能仕様; IPC-4761 Design Guide for Protection of Printed Board Via Structures; IPC-4552 Performance Specification for Electroless Nickel/Immersion Gold (同意する) Plating for Printed Boards
UL (引き受けの研究所) – UL 94 Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances
Taiyo Tech (TUC) – TU-872 SLK High-Speed Material Technical Data