Printed Copper Wick Structure for Thin Vapor Chamber Cooling
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Solution Overview
Problem
Existing vapor chambers have thick wicks with poor water absorption and heat transfer performance, which cannot meet the demands of miniaturized electronic products.
Innovation Solution
A copper paste for printing a capillary structure, composed of copper powder, high molecular polymer, solvent, binder, dispersant, leveling agent, tackifier, and antioxidant, is used to create a wick with controlled thickness and enhanced structural strength, water absorption, and heat transfer performance by blade coating or screen printing, followed by binder removal and sintering in hydrogen or hydrogen-nitrogen gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick wick is used in the vapor chamber, then the structural strength is improved, but the thickness of the vapor chamber increases and heat transfer performance deteriorates
Solution Approach 1:
The patent employs a porous copper paste containing copper powder particles with diameter of 3-10 μm and porosity of 40-60%, creating a three-dimensional interconnected open space structure with pore size of 1-30 μm. This porous structure provides both mechanical strength and excellent capillary action for water transport, enabling thin wick design (10-100 μm) while maintaining structural integrity and heat transfer performance.
Solution Approach 2:
The invention uses a multi-component paste formulation with different functional materials distributed throughout the wick structure. The copper powder provides thermal conductivity and structural framework, while the polymer binder and pore-forming agents create localized porous channels optimized for water flow. This local optimization of material properties enables the thin wick to simultaneously achieve strength, water absorption, and heat transfer functions.
2Strength
If a thick wick is used in the vapor chamber, then the structural strength is improved, but the water absorption performance deteriorates
Solution Approach 1:
The porous copper paste with 40-60% porosity and interconnected pore structure of 1-30 μm size provides excellent capillary action that enhances water absorption performance. The high surface area to volume ratio of the porous structure increases the contact area with water, improving wicking efficiency while maintaining structural strength through the copper powder framework.
Solution Approach 2:
The invention uses a composite paste formulation combining copper powder (providing strength and thermal conductivity) with polymer binders and pore-forming agents (providing porosity and water absorption). This composite structure synergistically combines the mechanical properties of copper with the water-absorbing capabilities of the polymer matrix, achieving both structural strength and superior water absorption in a thin wick design.
3Reliability
If the particle size of copper powder is reduced, then the heat transfer performance is improved, but the manufacturing precision and structural strength deteriorate
Solution Approach 1:
The patent specifies precise particle size parameters for copper powder (3-10 μm diameter) and employs controlled sintering parameters (temperature, time, atmosphere) to achieve the desired microstructure. By carefully controlling these parameters, the invention produces a consistent porous structure with 40-60% porosity and interconnected pores of 1-30 μm, ensuring both heat transfer performance and manufacturing repeatability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The copper paste enables the creation of a wick with a thickness of 10-100 μm, improved structural strength, and superior water absorption and heat transfer performance, effectively addressing the miniaturization needs of electronic products.
Implementation Method 1
sintering in hydrogen or hydrogen-nitrogen gas
Implementation Method 2
a capillary structure of the wick has a direct influence on the performance of the vapor chamber, and the capillary structure requires a strong capillary force and small water flow resistance
Implementation Method 3
The vapor chamber is a heat-conducting component which realizes rapid heat transfer by the phase change of its internal working fluid
Data Source
AI summary
The present invention discloses a copper paste for printing a capillary structure and a preparation method thereof. The copper paste consists of copper powder, a high molecular polymer, a solvent, a binder, a dispersant, a leveling agent, a tackifier and an antioxidant. Through the limitation on the copper powder and the high molecular polymer in the copper paste of the present invention, the prepared copper paste can be applied to a carrier of a vapor chamber by blade coating or screen printing, and then used as a wick after binder removal and sintering in hydrogen or hydrogen-nitrogen mixed gas, so as to reduce device investment and cost; and the thickness of the wick can be accurately controlled to be 10-100 μm, the structural strength is higher, the water absorption performance and the heat transfer performance are better, and the demand for miniaturization of electronic products is met.