As AI capabilities accelerated rapidly through 2025, the competition for computing power has driven chip miniaturization and higher integration density. The development of technologies ranging from Microchannel Liquid Cooling Plates (MLCP) to in-chip microfluidic cooling is not only transforming thermal management approaches — it is fundamentally reshaping the logic of chip manufacturing itself.
1. Three Core Manufacturing Processes for MLCP
MLCP manufacturing requires micron-level precision while balancing efficiency, cost, and reliability. Three mainstream processes have emerged: metal 3D printing, precision etching, and micro-milling/skiving — each suited to different application scenarios.
Metal 3D printing, primarily Selective Laser Melting (SLM), has become the go-to technology for high-end MLCP prototype manufacturing due to its integrated forming advantage. The key breakthrough is the use of green laser technology — copper absorbs green laser at 40% efficiency, resolving the challenge of processing highly reflective metals with conventional infrared lasers, achieving channel precision of 50μm.
Complete process flow:
• CAD modeling: topology-optimized channel network design, ensuring pressure drop ≤30kPa while maximizing heat dissipation area
• Metal powder spreading: pure copper powder with particle size 15–53μm, layer thickness controlled at 20μm
• Laser melting: 200–500W laser power, 1,000–2,000mm/s scan speed, achieving full-density fusion
• Post-processing: electropolishing reduces surface roughness to Ra<1.6μm, eliminating inter-layer print defects
Key advantage: seamless integrated forming with 50% better thermal performance than CNC machining. Especially suited for small-batch high-end prototypes such as NVIDIA Rubin/Feynman platforms.
Precision Etching: The Workhorse for Mass Production
Precision etching borrows from semiconductor photolithography, using chemical solutions to etch microchannels into metal substrates. It is the dominant technology for high-volume MLCP production. Key specs: flatness ≤0.02mm/m, channel dimension tolerance ±5μm, with hundreds of substrates processable per batch. Ideal for automotive electronics and general-purpose server applications.
Typical process flow:
• Substrate cleaning: ultrasonic cleaning of pure copper or Al 6061 substrates, pre-treating surface roughness to Ra<0.8μm
• Photoresist coating: spin-coating positive photoresist at 1–3μm thickness, baking at 90°C for 30 minutes
• Exposure & development: mask exposure followed by developer removal of unexposed resist to reveal channel patterns
• Etching: acidic etchant (H₂SO₄-H₂O₂ system for copper), etch rate 2μm/min, achieving channel depths of 30–150μm
• Strip & clean: alkaline solution strips remaining photoresist, followed by ultrapure water rinse and drying
Industry application: Chinese firm Gaolan Co. achieved 40% higher thermal efficiency via 3D microchannel cold plates with vortex stabilization design, entering the NVIDIA H100/GB300 core supply chain.Read our analysis of NVIDIA's latest cooling technology.
Micro-milling / Skiving: The Balanced Choice for Mid-Volume Production
Micro-milling and skiving offer strong equipment compatibility and flexible customization, making them important complements for small-to-medium volume MLCP production. Each has distinct strengths.
Skiving process — high reliability focus:
• Dedicated skiving tools machine continuous microchannels in copper substrate, channel width accuracy ±10μm
• Vacuum brazing seal: 10⁻³Pa vacuum environment, brazing temperature 600–800°C for hermetic sealing.Our vacuum brazing furnaces are designed specifically for hermetic sealing in thermal component manufacturing.
• Laser-welded inlet/outlet fittings, final leak rate controlled at <10⁻³Pa·m³/s
Micro-milling process — precision focus:
• Ultra-fine carbide cutters (0.1–0.5mm diameter) directly mill channels to ±3μm accuracy
• Capable of complex serpentine or branched channel geometries; suited for medical devices and high-end low-volume applications
• Lower efficiency: 2–3 substrates/hour per tool, tool replacement every 10 substrates
Industry application: skiving is widely used in EV motor controller cooling; firms like Jiancework Precision achieve annual production capacity of 500,000 units via this process.
2. Next-Generation Chip Cooling: From Cold Plates to In-Chip Microfluidics
Conventional chip liquid cooling is essentially attaching a copper cold plate to the chip. Heat must pass through the silicon die, thermal interface material, and metal lid before the coolant can carry it away — each contact layer adding thermal resistance.
Engineers now etch thousands of micro pin fins and microchannels directly into the backside of the chip's silicon substrate, allowing coolant to flow in direct contact with the chip's heat-generating core. This precision manufacturing process requires specialized equipment and strict quality control.The pin fins are approximately 100μm in diameter and over 200μm deep — coolant flows just a few hundred micrometers from the active transistors, removing heat directly at the source.
Performance breakthrough: interlaced micro pin fin arrays dramatically increase heat transfer surface area, enabling chips to dissipate heat at more than twice their thermal design power (TDP).
Comparison with conventional approach (per IEEE paper data):
• Traditional cold plate liquid cooling: heat passes through multiple layers with high thermal resistance, limiting efficiency
• In-chip microfluidic cooling: coolant flows directly on chip backside, minimal thermal resistance, significantly improved efficiency
Two Manufacturing Pathways
Two main manufacturing pathways currently exist for microfluidic cooling chips:
• Lightweight path: purchase commercial chips, remove the lid, then machine microchannels — low cost and easy to prototype (adopted by Microsoft's team)
• Wafer-level integration: foundries etch microchannels directly during chip fabrication — suitable for mass production, avoiding the risks of post-lid-removal processing
3. Femtosecond Laser: A Key Manufacturing Tool for Next-Generation Microfluidic Cooling
Future chips will be complex 3D structures in which electrical connections and liquid cooling channels coexist. Thermal management will no longer be an add-on to chip design — it will be an integral part of it. Femtosecond laser technology is poised to play a major role in this transition.
Core Advantages of Femtosecond Lasers
• Ultra-short pulse duration (10⁻¹⁵s): minimizes heat-affected zone during processing, ideal for precision machining on fragile silicon chips
• Complex geometry capability: flexibly machines intricate pin fin shapes, channel grooves, and complex patterns
• Superior surface quality: achieves surface roughness of Ra 0.2μm, meeting chip-level microstructure requirements
Technology Outlook
Whether femtosecond laser's processing efficiency and mass production cost can meet chip manufacturing demands still requires further market validation. However, it is already a powerful tool for advancing the feasibility of next-generation in-chip microfluidic cooling — representing an important leap in thermal manufacturing technology from the macro to the micro scale.
4. Conclusion
Microchannel Liquid Cooling Plate (MLCP) manufacturing technology is in a phase of rapid evolution. The three core processes — metal 3D printing, precision etching, and micro-milling/skiving — each offer distinct advantages, playing central roles in high-end prototyping, mass production, and mid-volume custom applications respectively.
More significantly, as chip heat flux densities continue to climb, thermal management technology is migrating from outside the chip to inside it. In-chip microfluidic cooling represents the ultimate direction of thermal management evolution — and the maturation of precision manufacturing technologies such as femtosecond lasers will accelerate its real-world adoption.
Thermal management is no longer an add-on to chip design — it is a core component of chip architecture. Understanding when to use vapor chambers vs heat pipes is now a critical design decision in thermal architecture.This paradigm shift is reshaping the manufacturing logic of the entire semiconductor industry.
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Written by
CoolingThermal Engineering TeamCoolingThermal is an automation equipment manufacturer based in Kunshan, China, specializing in heat pipe and vapor chamber production equipment since 2017. Our engineering team designs, builds, and commissions complete production lines covering forming, degassing, welding, testing, and assembly processes. The technical content on this blog is written by the same team that develops the equipment — based on real production experience, not secondary research.
