Copper Electrolytic Solution Additive for Low Profile Foil
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Solution Overview
Problem
Conventional copper electrolytic foils have a rough surface that hinders fine patterning and 2-layer flexible substrates suffer from pinholes, leading to defects in printed wiring boards, while additives like thiourea compromise elongation and tensile strength.
Innovation Solution
A copper electrolytic solution containing a compound with a specific skeleton, obtained through an addition reaction involving epoxy groups, and an organic sulfur compound is used to achieve a low profile, enhancing elongation and tensile strength for fine patterning and uniform copper plating without pinholes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If large quantities of glue or thiourea are added to the electrolytic solution to lower the surface profile, then the rough surface profile is reduced, but the elongation percentage is dramatically lowered
Solution Approach 1:
The patent changes the chemical parameters of the electrolytic solution by introducing a specific compound with skeleton formula (I) containing epoxy groups and hydroxyl groups. This compound replaces conventional additives like glue or thiourea, achieving surface profile reduction while maintaining elongation properties through its unique molecular structure and interaction mechanisms with copper ions during electrolysis.
Solution Approach 2:
The patent employs a composite approach by combining the specific compound with skeleton formula (I) containing both epoxy and hydroxyl groups with conventional electrolytic solution components. This composite electrolytic solution achieves synergistic effects where the novel compound provides surface profile control while the existing solution components maintain electrical conductivity and copper deposition efficiency, thereby preserving elongation properties.
2Productivity
If conventional electrolysis is used to produce copper foil, then copper deposition is achieved, but the rough side develops severe bumps and pits that hinder fine patterning
Solution Approach 1:
The patent modifies the electrolytic solution composition by incorporating the specific compound with skeleton formula (I), which changes the deposition parameters during electrolysis. This compound adsorbs onto the cathode surface and anode surface, controlling crystal growth and reducing the formation of bumps and pits, thereby achieving both efficient copper deposition and improved surface uniformity for fine patterning applications.
3Ease of manufacture
If the underlying metallic layer is formed by dry plating on insulating film, then copper conductor layer can be formed, but pinholes occur due to exposure of insulating film through the metallic layer
Solution Approach 1:
The patent changes the electrolytic solution parameters by adding the specific compound with skeleton formula (I) before the copper electroplating step. This compound modifies the deposition behavior of copper ions, enabling the copper layer to better conform to the underlying metallic layer topology and fill in pinhole areas, thereby producing a defect-free copper conductor layer on 2-layer flexible substrates.
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 effectively reduces surface roughness, maintains elongation properties, and provides high tensile strength for copper foils and 2-layer flexible substrates, enabling fine patterning and defect-free copper plating.
Implementation Method 1
a potential differential is provided between these to electrodeposit copper onto the cathode drum
Implementation Method 2
a copper electrolytic solution containing as an additive a compound having a specific skeleton represented by General Formula (1) below, which is obtained by an addition reaction in which water is added to a compound having in a molecule at least one epoxy group
Data Source
AI summary
The object of the present invention is to obtain a low profile electrolytic copper foil with a low surface roughness at the rough surface side (opposite side from the glossy side) in the electrolytic copper foil manufacture using a cathode drum and, particularly, to obtain an electrolytic copper foil with excellent elongation and tensile strength that permits fine patterning. Another object is to obtain a copper electrolytic solution that allows uniform copper plating without pinholes on a 2-layer flexible substrate. This copper electrolytic solution contains, as an additive, a compound having the specific skeleton represented by General Formula (1) below which is obtained by an addition reaction in which water is added to a compound having in a molecule one or more epoxy groups:wherein A is an epoxy compound residue and n is an integer of 1 or more.