Dual-Side Cooling Clip Packaging for Low-Impedance Power MOSFETs: Applications & Future Trends

Introduction: When Thermal Management Becomes the Performance Bottleneck
 
In the realm of power semiconductors, a silent thermal revolution is underway. As traditional single-sided cooling reaches its physical limits, as AI server power consumption breaks through the kilowatt barrier, and as EV motor controllers endure hundreds of amps of current surges within highly constrained spaces, Dual-Side Cooling Clip technology has emerged. Hailed as the “ultimate thermal solution for power MOSFETs,” this innovation is redefining the performance boundaries of low-impedance devices.
1. From “Single-Sided Cooling” to “Dual-Sided Heat Dissipation”: The Technical Essence
1.1 The Thermal Dilemma of Traditional Packaging
 
  • RDS(on) increases by 40% as temperature rises, causing a sharp drop in efficiency.
  • Junction-to-ambient thermal resistance (RθJA) is generally > 30°C/W, creating a pronounced thermal bottleneck.
  • Power cycling lifetime is less than 100,000 cycles, significantly limiting reliability.
1.2 The Architectural Revolution of Dual-Side Cooling
Galaxy Microelectronics’ PDFN 5×6 DSC (Dual-Side Cooling) package achieves dual-sided heat dissipation through three major innovations:

① Clip Copper Strip Replaces Aluminum Ribbon: A 460μm thick copper strip is directly soldered to the top of the die, serving as the primary thermal conduction path.

② Top-Exposed Metal Pad: Forms a dual thermal path (top and bottom) in conjunction with the bottom drain.

③ Insulated Thermally Conductive Pad: The top connects to the heat sink via an insulating pad, achieving both electrical isolation and highly efficient thermal conductivity.

Measured Data: The junction-to-case thermal resistance of the TBLS009N04THSC is merely 0.85°C/W, representing a 20% reduction compared to traditional single-sided cooling. Under a high current of 100A, the product’s temperature rise is reduced by 5-10°C.
 
2. Unmatched Performance: Six Core Advantages of Dual-Side Cooling
 
2.1 Ultimate Thermal Dissipation Capability

The Core Secret: Heat is simultaneously conducted from both the top and bottom surfaces of the die, effectively doubling the cross-sectional area of the thermal flow path.

Case Study: In a 24V BMS system, 28 TBLS009N04THSC MOSFETs operate in parallel. Dual-side cooling reduces the system’s peak temperature from 136°C to 125°C, drastically lowering the MOSFET failure rate.

2.2 Sustained Ultra-Low Impedance

The Clip technology itself pushes RDS(on) down to 0.6mΩ (typ). Furthermore, its superior thermal management ensures that low impedance is maintained even at elevated temperatures:

  • At 25°C: 0.6mΩ
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  • At 175°C: Increases to merely 1.1mΩ (a temperature coefficient of only 1.8x, significantly lower than the 2-3x typical of aluminum ribbon bonding).
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2.3 High-Reliability Design

  • Power Cycling Lifetime: Dual-side cooling significantly reduces thermo-mechanical stress. Measured extreme endurance exceeds 500,000 cycles (compared to <100,000 for traditional packages).
  • Short-Circuit Withstand Capability: When 28 TBLS009N04THSC MOSFETs in parallel are subjected to a 2400A short-circuit current surge, the junction temperature remains within the safe zone after a 300ms pulse, whereas single-sided packages have already failed.
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3. Application Scenarios: How Dual-Side Cooling is Transforming Industries

3.1 Battery Management Systems (BMS) – The Core Battlefield

  • Pain Point: EV BMS systems must withstand instantaneous short-circuit currents of over 3000A, accompanied by extreme temperature spikes and stringent reliability requirements.
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  • The TBLS009N04THSC Solution:

    • 28-36 units connected in parallel for charge/discharge protection.
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    • 2400A Overcurrent Test: Temperature rise limited to 125°C (vs. 136°C for competitors).
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    • Short-Circuit Withstand Time: 0.3s, which is 50% longer than competing products.
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    • Top heat sinks connect directly to the battery enclosure, eliminating the need for additional heat sinks.
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  • Customer Validation: In a leading automaker’s BMS solution, adopting dual-side cooling reduced MOSFET usage by 20%, while actually lowering overall system costs by 15%.
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3.2 AI Server Power Supplies – A Power Density Revolution

  • Challenge: GPU power modules demand current densities exceeding 150A/in², making traditional packaging thermally inadequate.
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  • Value of Dual-Side Cooling:

    • Top heat sinks connect directly to the MOSFETs, halving the thermal resistance.
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    • Efficiency improves by 1.5%, saving thousands of kWh of electricity per rack annually.
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3.3 E-Drive Inverters – Uncompromising Reliability

  • Requirement: Automotive main traction drives require frequent start-stop cycles, demanding over 300,000 power cycles.
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  • Technical Match: The combination of Clip and dual-side cooling reduces solder joint stress by 60% and extends power cycling lifetime to over 500,000 cycles, fully meeting AEC-Q101 standards.
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4. Challenges & The Future: A Technology Evolution Roadmap

4.1 Current Challenges

  • Cost Pressure: Dual-side cooling adds top-side thermal processes, increasing costs by 15-20% compared to single-sided solutions.
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  • Design Complexity: PCBs must account for electrical isolation and thermal design on both sides, placing higher demands on engineers.
  • Lack of Standardization: Top-side cooling pad dimensions and insulation voltage ratings have not yet been unified.
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4.2 Galaxy Microelectronics’ Solutions

  • Process Optimization: Clip soldering yield rates have been increased to 99.5%, effectively reducing manufacturing costs.
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  • Design Tools: We provide comprehensive electrical and thermal simulation models.
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  • Customer Support: We offer free samples and technical support to ensure dual-side cooling achieves maximum performance.
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5. Technology Outlook: The Pursuit of Thermal Excellence is Endless

Dual-side cooling Clip technology is not merely a packaging improvement; it represents a paradigm shift in power semiconductor design philosophy. Supported by three pillars—dual thermal paths, low impedance, and high reliability—it underpins the next generation of power electronics systems.

Galaxy Microelectronics’ Vision: We aim to achieve 1 million units in sales for the TBLS009N04THSC by the end of 2026, while simultaneously developing a series of lower-impedance products such as the TBLS006N04THSC to continuously lead the industry.
For engineers, the window to transition from single-sided to dual-sided cooling is open right now. In high-performance applications like BMS, servers, and e-drives, dual-side cooling is no longer an option—it is an engineering imperative. For the industry, as standardization matures and costs decrease, dual-side cooling will become the new normal for power MOSFETs, much like flip-chip technology did previously.
 
The Dual-Side Era is Here. The Future is Promising!