KINJI Embedded Copper Coin PCB: High-Power Thermal Management & Reliable Interconnect Solution for EVs, IGBTs, and AI Servers

In high-power-density applications such as new energy vehicles (EVs), industrial IGBT modules, and high-performance computing (HPC) servers, the PCB’s thermal management, current-carrying capacity, and long-term reliability directly determine system stability and service life. KINJI introduces a 6-layer embedded copper coin PCB that integrates a monolithic copper embedding process, advanced HDI structure, and highly stable substrate materials. This solution delivers efficient heat dissipation, high current capability, and reliable interconnectivity—providing a solid hardware foundation for power electronics operating under harsh conditions.

Core Process & Parameters: Designed for High-Power Scenarios

Every parameter of this PCB is engineered around three core requirements—high power, high heat dissipation, and high reliability—achieving a deep integration of process and performance.

(For detailed parameter tables, please refer to KINJI’s official datasheet.)

Key Technology Breakthrough: Embedded Copper Coin Solves High-Power PCB Challenges

Conventional PCBs in high-power-density applications face three major challenges:

• Thermal runaway due to high thermal resistance
• Current-carrying bottlenecks caused by the skin effect
• Reliability failures induced by CTE (coefficient of thermal expansion) mismatch

KINJI’s innovative embedded copper coin technology systematically overcomes these issues through fundamental architectural improvements.

1. Vertical Heat Conduction Architecture – Breaking Local Heat Flux Density Bottlenecks

Traditional via‑based heat dissipation achieves a vertical thermal conductivity of only 10–20 W/(m·K), insufficient for local heat flux densities exceeding 100 W/cm² from devices like IGBTs and MOSFETs.
KINJI’s integrated copper coin process creates a highly conductive copper column (≈400 W/(m·K)) inside the PCB, enabling direct heat transfer from the heat source layer to multiple copper heat‑spreading layers. This reduces vertical thermal resistance by over 40%, keeps junction temperatures within safe limits, and eliminates thermal runaway and thermal fatigue failure.

2. Low-Impedance Current Path – Suppressing Skin Effect and Joule Heating

To overcome the reduced effective current‑carrying cross‑section caused by the skin effect in high‑frequency, high‑power circuits, the embedded copper coin provides a low‑impedance path capable of carrying hundreds of amperes continuously. Combined with 1 oz outer‑layer thick copper foil, it significantly reduces AC skin‑effect losses.
Compared to pure copper‑foil routing, the copper coin lowers DC loop resistance by more than 60%, substantially reducing Joule heat generation and improving power module conversion efficiency.

3. Embedded Integrated Design – Optimizing System Power Density

The copper coin is embedded between layers and integrally molded with the PCB substrate, requiring no additional off‑board space and leaving surface component placement and BGA fan‑out routing unaffected.
This design eliminates bulky external heat sinks and thermal pads, supporting miniaturization and weight reduction—ideal for space‑constrained applications such as EV controllers and industrial inverters.

4. CTE Matching Optimization – Enhancing Reliability Under Thermal Cycling

The copper coin’s CTE precisely matches that of the Shengyi S1000‑2M substrate material, effectively relieving shear stress caused by CTE mismatch during thermal cycling. This avoids common failure modes such as hole wall cracks, substrate delamination, and copper foil peeling.
Combined with 1‑step HDI buried/blind vias and resin plugging, the process eliminates blind‑via voids and plating voids, ensuring insulation reliability and mechanical stability under high‑voltage, high‑load conditions.

Proven Applications: Three High‑Power Market Segments

With customized process design and rigorous quality control, KINJI’s embedded copper coin PCBs have achieved volume production in multiple high‑reliability scenarios. Results are quantifiable, traceable, and recognized by industry leaders.

1. New Energy Vehicle Power Module (On‑Board Charger – OBC)

Customer & Scenario: A leading domestic EV manufacturer’s pure electric SUV OBC project requiring 22 kW fast charging in a compact space (≤280×180×60 mm), meeting AEC‑Q100‑grade thermal cycling from -40°C to 125°C, with device junction temperature below 150°C.

Original Pain Points: The customer’s aluminum‑based PCB + heat sink solution caused power MOSFET (IPB65R110CFD) junction temperatures to reach 178°C during fast charging, frequently triggering thermal protection and interrupting charging. The 12 mm‑thick heat sink occupied too much space.

KINJI Solution & Results:

• Custom 0.8 mm embedded copper coin placed directly under MOSFET leads
• MOSFET junction temperature reduced from 178°C to 153°C – fully automotive compliant
• 12 mm heat sink replaced by a 3 mm thin thermal pad
• PCB thickness reduced from 8.2 mm to 5.7 mm (30% volume reduction)
• Over 120,000 units delivered; passed 1,000 thermal cycles (-40°C to 125°C, 1 hour per cycle) with no delamination, cracking, or peeling
• Yield > 99.8% ; helped customer pass new‑energy vehicle certification

2. Industrial Power Electronics (11 kW Motor Drive Module)

Customer & Scenario: A leading domestic industrial inverter manufacturer’s 11 kW motor drive for mining machinery and assembly lines. Operating conditions: dust, high ambient temperature (up to 65°C), high vibration (10–50 Hz). Requirements: IGBT (FF300R12KT4) long‑term temperature ≤120°C, MTBF ≥20,000 hours.

Original Pain Points: Conventional 6‑layer PCB (no copper coin) resulted in IGBT hot‑spot temperature of 142°C and line voltage drop ≥0.8 V, causing frequent IGBT burnout and signal anomalies. Failure rate: 8.3%.

KINJI Solution & Results:

• Embedded 0.8 mm copper coins from layer 2 to 5 under the IGBT, optimized copper thickness
• IGBT hot‑spot temperature dropped from 142°C to 115°C
• Line voltage drop below 0.5 V
• Conversion efficiency improved from 94.2% to 96.7%
• Failure rate reduced to 1.7% ; MTBF increased to 28,000 hours
• Eliminated external cooling structures, reducing per‑unit cost by 8% , saving the customer over RMB 3 million annually in after‑sales and manufacturing costs

3. High‑Performance Server / Data Center Motherboard (AI Server Power Module)

Customer & Scenario: A leading domestic data center solution provider’s AI server for AI training and big data analytics. The power module must supply stable power to an Intel Xeon Platinum 8470C CPU and NVIDIA A100 GPU, continuously carrying 35 A with voltage ripple ≤±2%, module temperature ≤90°C, and supporting routing density ≥120 lines/inch.

Original Pain Points: Traditional PCB had insufficient current‑carrying capacity, causing module temperature of 98°C, excessive voltage drop, and unstable CPU/GPU power leading to throttling. Routing density was also insufficient.

KINJI Solution & Results:

• Embedded copper coin as the main low‑impedance path for the power supply loop
• DC loop resistance reduced by 62% ; voltage drop <0.3 V; voltage ripple ≤±1.5%
• Module operating temperature stably below 82°C – no throttling
• Routing density increased to 135 lines/inch (5.91/5.91 mil line width/spacing) using 1‑step HDI buried/blind vias
• Deployed in three large data center projects; over 80,000 units delivered; supports 24/7 continuous operation; compute output stability improved by 25% ; repeat orders received

KINJI Technical Support: Full‑Chain Assurance from Co‑Design to Volume Production

As a professional PCB manufacturer, KINJI provides end‑to‑end capabilities—from early design collaboration and process validation to mass production:

• Custom copper coin design – size, embedded layer, and placement optimized based on heat source distribution, power requirements, and installation dimensions; one‑on‑one DFMEA analysis to mitigate process risks.
• Strict quality control – compliant with IPC‑A‑600 and IPC‑6012; equipped with cross‑section analysis labs, thermal cycling test equipment, and insulation withstand voltage test systems. 100% visual inspection plus sample‑based thermal cycling and cross‑section validation ensure consistency.
• Reliability documentation – custom test reports, process documents, and environmental compliance certificates (RoHS, REACH, etc.) help customers accelerate product qualification and shorten project lead times.

Conclusion KINJI’s embedded copper coin PCB solves critical thermal management and current‑carrying challenges in high‑power scenarios through process innovation. With proven mass‑production success across EVs, industrial power equipment, and AI servers, it offers a customized solution that balances performance, reliability, and cost‑effectiveness. Whether in an electric vehicle’s power module, an industrial inverter, or a high‑performance computing server, this PCB serves as the invisible foundation for stable system operation—empowering customers to lead in the high‑power era and build a lasting competitive advantage.

KINJI Embedded Copper Coin PCB Product Showcase