Carrier-Attached Copper Foil for Fine-Patterned Circuit Fabrication
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Solution Overview
Problem
The existing copper foil manufacturing processes, particularly in the FCCL industry, face challenges in achieving fine-patterned circuits due to grain coarsening from high-temperature casting, excessive pinholes, and high costs associated with imported sputtering-processed products, which limits their application in the LCD industry and hampers the development of high-density interconnection technologies.
Innovation Solution
A carrier-attached copper foil with a two-layered structure comprising a stainless steel, titanium, aluminum, or nickel alloy carrier foil and a copper foil, where the copper foil is electroplated onto the carrier foil without a releasing layer, allowing for easy detachment at high temperatures, enabling improved peelability and reusability of the carrier foil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If copper foil thickness is continuously decreased to facilitate fine-patterned circuit fabrication, then manufacturing precision is improved, but the difficulty of fabrication increases dramatically and the copper foil becomes difficult to handle
Solution Approach 1:
A carrier foil is introduced as an intermediary substrate to support the ultra-thin copper foil (8 μm) during fabrication processes. The carrier foil provides mechanical strength and handling capability while allowing the copper foil to maintain its thin profile for fine-patterned circuit fabrication. The carrier foil is subsequently removed after the copper circuit patterns are formed.
2Manufacturing precision
If high-temperature casting process is used to enhance copper foil grain fineness, then manufacturing precision is improved, but excessive pinholes and low peeling strength occur
Solution Approach 1:
The patent applies a two-stage thermal process: first a low-temperature process (100-200°C) to form the copper foil on the carrier, then a high-temperature process (≥300°C) specifically for peeling the copper from the carrier. This parameter change approach allows grain fineness to be enhanced at low temperature while preserving peeling strength, and enables complete detachment at high temperature without compromising the copper foil quality.
3Manufacturing precision
If sputtering process is used to manufacture copper foil, then manufacturing precision is improved, but production cost increases significantly
Solution Approach 1:
The patent replaces the expensive sputtering process with an electroplating process to deposit copper foil on the carrier. Electroplating is a more cost-effective manufacturing method that can achieve similar or better copper foil quality (8 μm thickness with fine grain structure) while significantly reducing production costs. The electroplating process uses electrical current to deposit copper ions from solution onto the carrier surface.
4Ease of operation
If conventional releasing layer is used to enable copper foil detachment, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the conventional releasing layer from the structure. Instead of using a separate releasing layer that requires specific chemicals or complex removal processes, the invention achieves direct detachment of copper foil from the carrier foil through controlled high-temperature treatment (≥300°C for 1-2 hours). This simplifies the overall process structure while maintaining ease of operation.
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
This solution enhances the peelability of the copper foil from the carrier foil, allowing for the use of thinner copper foils in high-temperature operations, improving the manufacturing of fine-patterned circuits and reducing production costs, thus addressing the limitations of current FCCL processes and enhancing the competitiveness and supply chain completeness of the LCD industry.
Implementation Method 1
forming a copper foil onto the carrier foil
Implementation Method 2
The surface oxide layer is formed by spontaneous oxidization of the carrier foil under atmosphere
Implementation Method 3
the copper foil is detachable from the carrier foil after the carrier-attached copper foil is processed with a high-temperature operation
Data Source
AI summary
In an embodiment of the invention, a method for manufacturing a carrier-attached copper foil is provided. The method includes providing a carrier foil including stainless steel, titanium, aluminum, nickel or alloy thereof with a surface oxide layer, and forming a copper foil onto the carrier foil to prepare the carrier-attached copper foil.