# Copper Multilayer PCB Manufacturer in China| EBest Circuit (Best Technology)

_Published: 2025-08-20_

Table of Contents

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- What is Copper Multilayer PCB?
- What is Material of Multilayer Copper PCB?
- What Are Advantages of Copper Multilayer PCBs?
- What Are Applications of Copper Multilayer PCB?
- How to Design a Copper Multilayer PCB for Wearable Device?
- How was Copper Multilayer PCB Made?
- Why Choose EBest Circuit (Best Technology) as Copper Multilayer PCB Manufacturer?
- Our Copper PCB Capabilities
- How to Get a Quote for Copper Multilayer PCB Project?

What is **[copper multilayer PCB](https://www.bestpcbs.com/blog/2025/08/copper-multilayer-pcb-manufacturer-in-china-best-technology/)**? Let’s discover its material, benefits, applications, design guide for wearable device, production process through this blog.

**Are you troubled with these problems?**

- High-frequency signal degradation killing your design?‌
- Heat dissipation always a bottleneck?‌
- Yield rates dropping with layer stacking?‌

**EBest Circuit (Best Technology) can provide service and solutions‌:**

- Rapid Response‌ – 24/7 engineering support, samples delivered in 48 hours.
- Cost Efficiency‌ – Intelligent panelization + material reuse cuts costs by 15%.
- ‌Transparency‌ – Real-time production tracking with photo verification at key stages.

**Welcome to contact us if you have any inquiry for [copper multilayer PCB](https://www.bestpcbs.com/blog/2025/08/copper-multilayer-pcb-manufacturer-in-china-best-technology/): sales@bestpcbs.com.**

## What is Copper Multilayer PCB?

[Copper Multilayer PCB](https://www.bestpcbs.com/blog/2025/08/copper-multilayer-pcb-manufacturer-in-china-best-technology/)consist of alternating copper conductive layers and insulating materials (such as FR-4 or polyimide) bonded together through a lamination process. Copper’s high thermal conductivity (386W/m·K) and electrical conductivity support complex circuit designs, enabling high-density interconnection between layers through through-holes, blind vias, or buried vias.

This type of PCB is suitable for high-power applications (such as automotive electronics and 5G base stations), offering superior heat dissipation and signal stability compared to single- or double-layer PCBs. Its symmetrical structure (e.g., copper-prepreg-core-prepreg-copper) enhances mechanical strength and controls impedance. Some models also utilize thermal isolation technology to directly conduct heat.

[https://www.bestpcbs.com/blog/wp-content/uploads/2025/08/main-27.jpg](https://www.bestpcbs.com/blog/wp-content/uploads/2025/08/main-27.jpg)

## What is Material of Multilayer Copper PCB?

**1. Conductive Layer**

- Composition: Electrolytic copper foil (ED) or rolled copper foil (RA)
- Features: Thickness 0.5–6 oz/ft² (17–210 μm), conductivity ≥58 MS/m (20°C), surface finish available: brown oxide (OSP) or nickel-gold (ENIG).

**2. Insulation**

- FR-4: Epoxy resin + fiberglass, dielectric constant 4.2–4.8 (1 GHz), heat resistance 130°C (standard) / 170°C (high Tg).
- Polyimide (PI): Dielectric constant 3.4–3.6 (1 GHz), heat resistance >250°C, short-term temperature resistance ≥300°C.

**3. Prepreg (PP)**

- Composition: 7628/2116/1080 glass cloth impregnated with epoxy resin
- Features: Thickness 0.05–0.2mm (0.1–0.4mm after lamination), resin content 52%–65%, curing conditions 180°C/60min.

**4. Metal Substrate (Optional)**

- Aluminum Substrate: 1050/6061 alloy, thermal conductivity 180–220 W/m·K, thickness 1.0–3.2mm.
- Copper Substrate: Electrolytic copper, thermal conductivity 386 W/m·K, thickness 0.5–2.0mm.

**5. High-Frequency Material (Optional)**

- PTFE: Polytetrafluoroethylene, dielectric constant 2.2–2.5 (10 GHz), dissipation factor 100,000 bend cycles.
- Surface Finish: Apply ENIG (Electroless Nickel Immersion Gold) or OSP (Organic Solderability Preservative) to prevent copper oxidation and ensure solder reliability.
- Validation: Pass dynamic bend tests (radius 3mm, 1Hz frequency, 10,000 cycles) and accelerated aging (85℃/85%RH, 168 hours).

**7. Electromagnetic Compatibility (EMC) & Compliance**

- Grounding: Connect metal enclosures (e.g., wristband, buttons) to PCB ground via spring contacts or conductive adhesives, forming a Faraday cage to mitigate ESD.
- Certification: Achieve CE (EU) or FCC (US) EMC compliance, testing across 80MHz–6GHz to ensure stable operation in complex electromagnetic environments.
- Wireless Charging: Position Qi-standard coils at PCB edges, away from antennas and sensors to avoid interference.

[https://www.bestpcbs.com/blog/wp-content/uploads/2025/08/3-23.png](https://www.bestpcbs.com/blog/wp-content/uploads/2025/08/3-23.png)

## How was Copper Multilayer PCB Made?

**1. Substrate Preparation**

- Select FR4 glass fiber epoxy resin laminate as substrate, with copper foil cladding (thickness 1oz/2oz).

**2. Inner Layer Pattern Transfer:**

- Apply photosensitive dry film, transfer circuit pattern via UV exposure, and dissolve unexposed areas.
- AOI (Automatic Optical Inspection) verifies line precision and marks defects.

**3. Inner Layer Etching & Oxidation**

- Chemically etch copper not protected by dry film to form inner layer circuits.
- Black oxide/brown oxide treatment on copper surfaces to enhance interlayer adhesion.

**4. Lamination & Pre-Press**

- Stack inner layer core boards, prepreg sheets, and outer layer copper foils alternately, aligning via positioning holes.
- High-temperature/high-pressure lamination (180-200℃) melts resin to fill gaps, forming a unified board.

**5. Mechanical Drilling**

- CNC drilling machine processes through-holes/blind holes with diameter accuracy ±0.05mm.
- Clean hole-wall resin residues (desmear).

**6. Electroless Copper Plating**

- Deposit electroless copper (0.3-0.8μm) on hole walls to establish conductive base.
- Electroplate to thicken copper layer (20-25μm) for reliable hole-wall conductivity.

**7. Outer Layer Pattern Transfer**

- Repeat inner layer pattern transfer process, addressing hole alignment.
- Use high-precision exposure equipment to compensate for interlayer deviation.

**8. Outer Layer Etching & Stripping**

- Secondary etching defines outer layer circuits, with tin layer protecting desired copper areas.
- Alkaline solution strips dry film, retaining circuit patterns.

**9. Solder Mask & Silkscreen**

- Apply liquid photosensitive solder mask (green/black), expose and develop to expose pads.
- Silkscreen component identifiers (white/yellow text).

**10. Surface Finish**

- Treat pad areas with ENIG (Electroless Nickel Immersion Gold)/immersion tin/OSP to prevent oxidation and enhance solderability.
- Plate gold finger areas with hard gold for wear resistance (e.g., board-edge connectors).

**11. Electrical Testing**

- Flying probe test or bed-of-nails test verifies continuity and insulation.
- AOI re-inspects for micro-shorts/opens.

**12. Profiling & Packaging**

- CNC milling cuts board outlines; V-score or punching for separation.
- Final cleaning, drying, and vacuum moisture-proof packaging.

[https://www.bestpcbs.com/blog/wp-content/uploads/2025/08/2-16.png](https://www.bestpcbs.com/blog/wp-content/uploads/2025/08/2-16.png)

## Why Choose EBest Circuit (Best Technology) as Copper Multilayer PCB Manufacturer?

Reasons why choose us as **[copper multilayer PCB manufacturer](https://www.bestpcbs.com/blog/2025/08/copper-multilayer-pcb-manufacturer-in-china-best-technology/)**:

- 19 years of experience in copper substrate R&D: Precisely addressing interlayer heat dissipation and current carrying challenges in high-power multi-layer copper substrates, ensuring long-term stable operation of high-power devices (such as projectors/lasers).
- Triple international quality certification (ISO9001/IATF16949/ISO13485): Medical and automotive-grade copper substrate production standards ensure ±1μm copper thickness uniformity in multi-layer board holes and zero deviation in electrical performance.
- Customized thermal management solutions for copper substrates: Embedded copper pillars/thermoelectric separation structures reduce the thermal resistance of multi-layer boards to 0.5°C/W, extending the life of LEDs/power modules by over 30%.
- Cost-optimized copper substrate design: Utilizing a gradient copper foil thickness (1oz outer layer + 2oz inner layer) to balance conductivity and heat dissipation requirements, saving 15% in material costs compared to traditional designs.
- 24-hour copper substrate rapid prototyping service: Laser drilling and electroless copper plating processes deliver high-complexity (20+ layers) copper substrate prototypes within 48 hours, accelerating the validation cycle for high-power products.
- Free Copper Substrate Design for Material (DFM) Analysis: Preemptively identify design risks such as copper layer distribution and blind via alignment, preventing interlayer cracking caused by thermal expansion coefficient mismatch and reducing secondary re-board rework costs.
- 100% Automated Optical Inspection (AOI): Detects hole wall voids and copper nodules, a common feature of copper substrates, with a 0.01mm² level of defect detection, ensuring zero defective batch orders.
- Full-Process Copper Substrate Solution: From thermal simulation (Flotherm) to copper layer etching and surface treatment (ENIG/HASL), we provide a one-stop service, reducing the cost of coordinating multiple suppliers.
- Ultra-Thin Copper Substrate Process (0.2mm total thickness): Combining flexible PI substrate and copper foil calendering technology, we achieve a bend radius of less than 1mm for multi-layer copper substrates for wearable devices while maintaining a current density of 10A/cm².

## Our Copper PCB Capabilities

**Items**
**Technical Parameters**

Product model
Copper PCB

Copper trace thickness
1OZ, 2OZ, 3OZ, 4OZ, up to 10OZ

Thermal Conductivity
1.0, 1.5, 2.0, 3.0W/m.K

Surface finishing
HAL(LF)/ Gold Immersion/ Gold plating/ OSP/ Immersion Tin/ Silver Immersion

Soldermask Color
White/Black/Green/Blue/Red/Yellow

Layers
1L, 2L, 4L, 6L, 8L, double sided, COB

Maximum dimension
1,100mm*480mm; 1,500x300mm

Minimum dimension
5mm*5mm

Minimum Line width/space
0.1mm/0.1mm

Warp and twist rate
≤0.75%(thickness:1.6mm, measurement:300mm×300mm)

Board Thickness
0.3－4.5mm

Die-Punching dimension tolerance
±0.15mm

V-cut positioning tolerance
±0.1mm

Manufacturing capability
6000m2

Wall Cu thickness
15-25um

Alignment tolerance
±0.076mm

Minimum diameter of die-punching hole
Thickness <=1.0mm:   1.0mm

Thickness 1.2-3.0mm: 1.5mm

Thickness 4.0mm: 2.0mm

Minimum size the square groove/slot/cutout
Thickness <=1.0mm:  0.8mm×0.8mm

Thickness 1.2-3.0mm:  1.0×1.0mm

Thickness 4.0mm:  1.5×1.5mm

Outline Tolerance
CNC routing：±0.1mm; Die-punching：±0.15mm

Minimum diameter of hole
0.3mm; not limit for maximum diameter of hole

Surface Finishing Thickness
gold plating：Ni 2.5-5um,  Au: 0.025－0.075um

immersion gold: Ni 3-6um, Au: 0.025-0.1um

HAL(LF): 3-30um

V－cut Angle tolerance
±5°

V-cut Range
0.3mm-4.5mm

Smallest silkscreen height
0.15mm

Smallest PAD
0.1mm

## How to Get a Quote for Copper Multilayer PCB Project?

**Essential Documentation for Copper Multilayer PCB Quotation**

- Lamination Stackup Drawing: Specify layer materials (e.g., FR-4/Rogers 4350), copper thickness (1–6OZ), dielectric thickness (mm), and impedance control targets.
- Gerber Files: Include circuit layers, drilling layers, and solder mask layers. Annotate trace width/spacing (e.g., 4/4mil), blind/buried via positions, and hole tolerance (±0.05mm).
- PCB Technical Parameter Sheet: Board dimensions (L×W×T), layer count (e.g., 8L), surface finish (ENIG/OSP), and special processes (via plating/half-hole).
- Impedance Control Requirements: Define differential pair impedance (e.g., 100Ω±10%), reference layers, and testing methods.
- Acceptance Criteria: Specify IPC class (e.g., IPC-6012 Class 3) and testing items (flying probe/AOI/X-ray).
- Quantity & Lead Time: Prototype/batch quantity (e.g., 5pcs/1k) and desired delivery timeline (e.g., 7-day expedited).
- Special Requirements: High-frequency/thermal needs (e.g., PTFE hybrid), environmental certifications (RoHS/UL).

**Why Partner with EBest Circuit (Best Technology)?**

- Expertise: Handles 16+ layer thick copper (6OZ) and hybrid high-frequency boards.
- Speed: Offers 48-hour quick quotes and complimentary impedance calculation.
- Quality: Free DFM review to eliminate design flaws upfront.
- Result: Avoid cost overruns, accelerate time-to-market, and ensure compliance for demanding applications.

Welcome to contact us if you have any request for copper multilayer PCB: **[sales@bestpcbs.com](mailto:sales@bestpcbs.com)**.