Background

As artificial intelligence, electric vehicles, 5G communications, and high-performance consumer electronics continue to evolve, power density in electronic devices is increasing at an unprecedented pace. Industry forecasts estimate that from 2025 to 2035, the global thermal management market will grow at a compound annual rate of approximately 10–15%, potentially reaching USD 300–400 billion by 2035. China alone is expected to account for more than 30% of this market.

In this context, heat dissipation components are no longer secondary accessories. They have become mission-critical elements that directly determine system performance, reliability, and service life. This shift is forcing both thermal design and manufacturing technologies to move toward higher efficiency, greater precision, and deeper integration—placing unprecedented demands on joining and sealing processes.

Industry Drivers for Advanced Heat Spreader Manufacturing

Across multiple sectors, thermal challenges are reshaping design requirements:

1.AI and Data Centers

Ultra-high computing density pushes GPU and ASIC chips to extreme heat flux levels, often exceeding hundreds of watts per square centimeter. This drives demand for high-density vapor chambers and advanced liquid cooling solutions.

2.3C Consumer Electronics

Smartphones, wearables, and laptops require ultra-thin thermal solutions that balance performance and heat dissipation within extremely limited space, relying on vapor chambers, graphite, and composite materials.

3.New Energy Vehicles

Battery packs and power electronics demand uniform temperature control, high safety margins, and lightweight, highly integrated thermal systems.

4.Telecom Base Stations

Continuous high-power operation in harsh outdoor environments requires thermal solutions with exceptional reliability, corrosion resistance, and long-term stability.

These demands are accelerating the transition of heat spreader designs toward complex internal structures, tight tolerances, and airtight sealed cavities, fundamentally changing how these components must be manufactured.

Limitations of Traditional Joining Technologies

Conventional heat spreader manufacturing has relied on brazing, mechanical pressing with adhesive bonding, and friction stir welding. However, each approach shows clear limitations when applied to next-generation VC (Vapor Chamber) products.

1.Brazing

Brazing introduces filler materials with thermal conductivity far lower than copper or aluminum, creating additional interfacial thermal resistance. Full-body heating can also deform thin fins or plates, while flux residues and porosity raise concerns about long-term reliability and cleanliness—especially for vacuum chambers.

2.Mechanical Pressing and Epoxy Bonding

These non-metallurgical joints suffer from high contact thermal resistance, poor sealing performance, and long-term aging risks such as cracking or delamination under thermal cycling.

3.Friction Stir Welding

While strong, friction stir welding faces accessibility challenges and is difficult to apply to enclosed cavities, micro-scale features, or complex three-dimensional structures commonly found in modern vapor chambers.

Why Laser Welding Is Transforming Heat Spreader Manufacturing

Laser welding has emerged as a core enabling technology for advanced thermal components due to its high energy density, precise controllability, minimal heat input, and excellent automation compatibility.

Key Advantages of Laser Welding for Heat Spreaders

1.Low Thermal Resistance and Superior Sealing

Laser welding forms true metallurgical bonds with weld compositions close to the base material. This minimizes interfacial thermal resistance while providing high mechanical strength and excellent airtightness—critical for vapor chambers.

2.Minimal Deformation and Dimensional Stability

Precisely controlled heat input significantly reduces warpage, preventing fin collapse or plate distortion and ensuring long-term flatness and reliability.

3.Micro-Scale Precision for Complex Structures

Laser welding enables micron-level weld seams without damaging nearby micro-channels or capillary structures. Non-contact processing and optical beam steering allow flexible 2D and 3D welding paths.

4.Broad Material Compatibility

Copper, aluminum, stainless steel, titanium, and dissimilar material combinations (such as Cu-Al or Cu-SUS) can be reliably welded, supporting lightweight and high-performance thermal designs.

VC Vapor Chambers: The Pinnacle of Passive Thermal Technology

Among all passive cooling solutions, vapor chambers and loop heat pipes represent the highest level of thermal engineering. Vapor chambers are widely adopted to address thermal bottlenecks in smartphones, GPUs, and data-center processors.

How VC Vapor Chambers Work

VC vapor chambers rely on a closed-loop phase-change process:

• Evaporation – Heat from the chip causes the working fluid to vaporize within a vacuum cavity.
• Vapor Spreading – Vapor rapidly distributes heat across the entire chamber.
• Condensation – Vapor releases latent heat and condenses at cooler regions.
• Capillary Return – Liquid is returned to the heat source via micro-porous wick structures, without mechanical pumps.

Compared with traditional heat pipes, vapor chambers offer two-dimensional heat spreading, higher effective thermal conductivity (10,000–20,000 W/m·K), and superior compatibility with multiple heat sources.

Key Laser Welding Processes in VC Manufacturing

1.Laser Spot Welding for Wick (Mesh) Fixation

Laser spot welding is used to secure copper mesh or sintered wick structures to the VC base plate. This process requires extremely low and precise energy control to avoid burn-through or mesh damage.

Typical challenge:

Welding ultra-thin copper (≈0.05–0.06 mm) with micron-level penetration control.

VC spot mesh effect	Copper mesh specifications

Weld morphology A	Weld morphology B

Solution:

Han’s Laser employs precision micro laser welding machines with millijoule-level energy control, achieving stable penetration below 30 μm and virtually no backside marking—currently an industry-leading capability.

Weld spot depth data	Metallographic cross-section

2.Laser Pre-Fixation Welding of Top and Bottom Covers

Pre-fixation welding temporarily joins the upper and lower VC plates, improving assembly accuracy before final sealing.

Key requirements:

• Consistent weld depth across large areas
• Sufficient mechanical strength without burn-through
• Stable galvanometer scanning over wide surfaces

Laser welding delivers uniform, high-strength joints while maintaining flatness in ultra-thin VC structures.

Weld spot appearance	Metallographic cross-section

3.Laser Edge Sealing Welding

Edge sealing is the most critical step for ensuring airtightness. High-energy laser seams precisely fuse the VC perimeter, forming a continuous hermetic seal with minimal distortion.

Compared with brazing, laser sealing reduces contamination, energy consumption, and deformation while improving yield.

Weld seam appearance	Metallographic cross-section

4.Laser Port Sealing After Fluid Filling

After vacuum evacuation and working fluid injection, laser welding is used to seal the fill port.

Key challenges:

• Avoiding spatter and micro-cracks
• Maintaining internal vacuum integrity
• Supporting ultra-thin VC thickness (0.2–3 mm)

Laser welding provides micron-level accuracy and excellent sealing reliability under internal pressure.

Weld seam appearance	Product metallography

5.Laser Welding Between VC and Structural Components

VCs are often welded directly to aluminum or stainless-steel structural parts to form integrated thermal modules.

Laser welding ensures:

• High positional accuracy
• Minimal heat impact on internal working fluid
• Seamless integration with automated production lines

This step is critical for ensuring system-level thermal performance and long-term reliability.

5VC-to-mid plate welding	Metallographic cross-section

Breaking the Thermal Bottleneck in the AI Era

As AI computing power continues to scale, thermal performance has become a limiting factor for hardware evolution. VC vapor chambers are at the center of this challenge—and laser welding is the technology that enables their precision, reliability, and mass production.

Han’s Laser has developed a complete, micron-level VC laser welding solution covering spot welding, pre-fixation, edge sealing, port sealing, and structural integration. These solutions have been widely adopted by leading VC manufacturers worldwide, establishing Han’s Laser as a key technology leader in VC heat spreader laser welding.

By combining advanced laser sources, precision motion control, and deep process expertise, Han’s Laser continues to push the boundaries of thermal manufacturing—supporting the next generation of high-power, high-reliability electronic systems.