Insulating Resin Circuit Substrate with Screen-Printed Copper Paste
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Solution Overview
Problem
The existing metal-based circuit substrates face issues with poor insulation between circuit patterns due to residual copper from etching treatments, which worsens with increased current and heat generation, requiring improved insulation and thermal conductivity.
Innovation Solution
An insulating resin circuit substrate with a circuit layer of spaced metal pieces, where the metal element area rate in gaps is less than 2.5%, and a heat radiation layer with a joining rate of 70% or more, made of materials with higher thermal conductivity than the resin, ensuring efficient heat radiation and stable insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a copper foil is subjected to an etching treatment to form a circuit pattern, then the circuit layer can be formed with good conductivity, but copper residue remains in the insulating resin layer causing poor insulation between circuit patterns
Solution Approach 1:
The patent extracts the circuit pattern formation process from the etching method and uses a screen print paste application method instead. This allows the copper-based paste to be applied in a controlled manner through a screen, preventing residue formation while maintaining circuit conductivity and insulation between patterns.
Solution Approach 2:
The patent changes the physical state and composition parameters of the circuit material from pure copper foil to a copper-based paste containing glass powder and organic vehicle. This parameter change enables better adhesion to the insulating resin layer and complete curing without residue, solving the insulation problem.
2Power
If the circuit layer is thickened to ensure conductivity and thermal conductivity for increased current, then the current carrying capacity improves, but copper residue tends to remain more in the insulating resin layer causing poor insulation
Solution Approach 1:
The patent uses a composite copper-based paste material containing copper powder, glass powder, and organic vehicle. This composite formulation allows the circuit layer to achieve both high conductivity for increased current and complete adhesion to the insulating resin layer, preventing copper residue formation even when the circuit layer is thickened.
Solution Approach 2:
The patent changes the material composition parameters by incorporating glass powder and organic binders into the copper-based paste. This enables the circuit layer to maintain structural integrity and complete adhesion at increased thicknesses required for high current applications, while preventing copper residue that would compromise insulation.
3Adaptability or versatility
If an etching treatment is used to form circuit patterns, then the circuit design flexibility is improved, but the insulating properties between circuit patterns deteriorate due to copper residue
Solution Approach 1:
The patent extracts the circuit pattern formation from the etching process and implements it through screen printing with a copper-based paste. This approach maintains circuit design flexibility by allowing various patterns to be created through screen design while ensuring complete adhesion and no copper residue, thus preserving insulation properties.
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 solution provides excellent insulating properties and heat radiation characteristics, reducing the risk of poor insulation and enabling stable use, even with increased current and heat, by minimizing copper residue and enhancing thermal conductivity.
Implementation Method 1
the heat radiation layer is made of a material having a thermal conductivity higher than a thermal conductivity of the insulating resin layer
Data Source
AI summary
There is provided an insulating resin circuit substrate including an insulating resin layer and a circuit layer consisting of a plurality of metal pieces disposed to be spaced apart in a circuit pattern shape on one surface of the insulating resin layer, in which in a case where a surface of the insulating resin layer in a gap between the metal pieces is analyzed by SEM-EDX, the area rate of a metal element constituting the metal pieces is less than 2.5%.