Copper Surface Adhesion via Non-Etching Protector Solution
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Solution Overview
Problem
Current methods for increasing adhesion strength between copper or copper alloy surfaces and organic layers in printed circuit boards (PCBs) are inadequate, particularly for fine line circuitries, as they often result in insufficient adhesion leading to delamination, and existing etching methods are not suitable for high-frequency applications.
Innovation Solution
An acidic aqueous non-etching protector solution comprising amino azoles, organic acids, and peroxides is used to enhance adhesion without etching or significant copper removal, maintaining a nano-roughened surface layer to improve bonding with organic layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional etching methods are used to increase adhesion strength, then adhesion strength is improved, but surface integrity is worsened and copper removal occurs
Solution Approach 1:
The invention changes the chemical parameters of the surface treatment by using a non-etching protector solution with specific composition (amino azole, organic acid, peroxide) and controlled pH value, thereby improving adhesion strength without causing copper removal or surface damage that occurs with conventional etching methods
Solution Approach 2:
The invention converts the harmful effect of copper surface oxidation into a beneficial process by using the non-etching protector solution to form a protective layer that actually enhances adhesion while preventing the harmful etching and copper removal that would otherwise occur
2Strength
If etching methods are used to increase surface area for adhesion, then adhesion strength is improved, but manufacturing precision is worsened due to copper removal
Solution Approach 1:
The invention changes the surface treatment parameters from etching-based to non-etching protector solution-based, maintaining the original copper surface dimensions and precision while achieving improved adhesion through chemical modification of the surface properties
3Strength
If strong etchants are used to roughen copper surface, then adhesion strength is improved, but loss of substance increases due to excessive copper removal
Solution Approach 1:
The invention converts the harmful effect of copper removal into a beneficial non-etching process by using a protector solution that forms a protective layer on the copper surface, thereby achieving adhesion enhancement without the substance loss associated with conventional etching methods
Solution Approach 2:
The invention changes the chemical approach from aggressive etching to gentle non-etching protection, using specifically formulated solutions with controlled composition and pH to achieve adhesion strength without copper loss
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 method significantly increases adhesion strength between copper or copper alloy surfaces and organic layers, preventing delamination and maintaining surface integrity, making it suitable for fine line circuitries and high-frequency applications without the drawbacks of conventional etching methods.
Implementation Method 1
contacting said substrate comprising said surface with an acidic aqueous non-etching protector solution comprising one or more than one amino azole, one or more than one organic acid and/or salts thereof, one or more than one peroxide in a total amount of 0.4 wt-% or less
Implementation Method 2
one or more than one peroxide in a total amount of 0.4 wt-% or less, based on the total weight of the protector solution
Implementation Method 3
oxidizing Cu-(0) into Cu—(I) and Cu-(II), respectively, and subsequently reducing at least partly this Cu—(I) and Cu-(II), respectively, into Cu-(0)
Data Source
AI summary
The present invention relates to a method for increasing adhesion strength between a surface of copper or copper alloy and an organic layer, the method comprising in this order the steps:(i) providing a non-conductive substrate comprising on at least one side said surface, said surface having a total surface area of copper or copper alloy,(ii) contacting said substrate comprising said surface with an acidic aqueous non-etching protector solution comprising(ii-a) one or more than one amino azole,(ii-b) one or more than one organic acid and/or salts thereof,(ii-c) one or more than one peroxide in a total amount of 0.4 wt-% or less, based on the total weight of the protector solution, and(ii-d) inorganic acids in a total amount of 0 to 0.01 wt-%, based on the total weight of the protector solution,wherein during step (ii) the total surface area of said surface is not increased upon contacting with the protector solution.