8-Layer High-Reliability PCB with TU-865™ (TG180 FR-4) with 10oz heavy copper

8-Layer High-Reliability PCB with TU-865™ (TG180 FR-4)

1. Product Overview

This product is an 8-layer high-reliability printed circuit board engineered for harsh environment applications requiring exceptional thermal stability, high current-carrying capacity, and robust mechanical strength. The design uses TU-865™ laminate—a halogen-free, high-Tg (TG180) epoxy resin system reinforced with E-glass fabric—manufactured by Taiwan Union Technology Corporation.

The board measures 120 mm x 120 mm and is supplied as a single piece. With 10 oz (350 µm) finished copper per layer and a total finished thickness of 4.5 mm, this PCB is designed for high-power, high-thermal-cycling applications such as automotive electronics, server power supplies, and base station equipment.

The structure incorporates blind vias, buried vias, half-holes (castellated edges), and all vias filled with conductive copper paste to ensure reliable interconnections and thermal management. Both top and bottom layers feature green solder masks with white lettering, finished with immersion gold (ENIG) for excellent solderability and corrosion resistance.

2. Product Specifications

Stack-Up Structure (8 Layers)

3. TU-865™ Laminate Introduction

TU-865™ is a halogen-free, high-Tg (TG180) epoxy laminate reinforced with E-glass fabric, manufactured by Taiwan Union Technology Corporation (TUC). The material is designed to meet the demanding requirements of harsh environment, high-reliability applications while delivering superior electrical performance.

According to the TU-865 datasheet:

TU-865 achieves flammability class of UL94V-0 by incorporating phosphorus and nitrogen compounds. This series of green materials eliminates the use of halogenated resins with excellent performance due to the potential hazardous effects from environmental concerns.

The material is available as TU-865 core and TU-865P prepreg, making it suitable for single/double-sided as well as multilayer PCB applications.

Key Features

TU-865™ Datasheet Summary

4. Application Areas

The combination of TU-865’s high Tg, halogen-free composition, and mid-loss electrical performance makes this 8-layer, 10-oz copper PCB suitable for a wide range of demanding applications:

Automotive Electronics – Engine control units (ECUs), battery management systems (BMS), power distribution modules, and ADAS power supplies benefit from the material's excellent thermal cycling resistance and anti-CAF capability.

Harsh Environments – Industrial controls, power inverters, motor drives, and down-hole drilling equipment require the robust mechanical and thermal properties of TU-865.

Servers & Data Centers – High-current backplanes, power supply units (PSUs), and RAID controllers leverage the material's high Tg and heavy copper support.

Telecommunications – Base station power amplifiers, RF front-end modules, and 5G remote radio units (RRUs) utilize the mid-loss electrical performance at frequency.

High-Reliability Systems – Aerospace power converters, railway traction systems, and medical imaging equipment demand the UL94V-0 flammability rating and proven reliability of TU-865.

5. Special Fabrication Features

This PCB includes several advanced features to support high-power, high-density, and high-reliability designs:

5.1 Blind Vias & Buried Vias

5.2 Half-Holes (Castellated Edges)

Purpose: Plated half-holes along the board edge, typically used for module-to-motherboard soldering or as test points.

Benefit: Enables the PCB to function as a surface-mount module (similar to a QFN package) or allows edge-mounted connectors.

5.3 Conductive Copper Paste Via Fill

Fabrication Notes for TU-865 (Heavy Copper, 10 oz)

6. Summary

This 8-layer heavy copper PCB leverages the high-Tg, halogen-free, and mid-loss properties of TU-865™ laminate to deliver exceptional reliability in harsh environments. With 10 oz copper per layer, 4.5 mm finished thickness, and a full suite of advanced features—blind vias, buried vias, half-holes, and conductive copper paste via fill—this board is purpose-built for high-power automotive, telecom, server, and industrial applications.

The green solder masks with white lettering (both sides) and immersion gold (ENIG) surface finish ensure excellent solderability, corrosion resistance, and visual clarity for assembly and inspection.

For the latest TU-865 datasheets, processing guidelines, and application notes, please contact Taiwan Union Technology Corporation (TUC) or visit their official website.