Copper Etchant Composition for Stable Surface Smoothness
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Solution Overview
Problem
Existing copper etchants, particularly sulfuric acid hydrogen peroxide-based etchants, struggle to maintain the smoothness of copper surfaces after etching, especially when continuous etching treatments are performed, leading to unstable etching performance and potential deterioration of wiring shape and characteristics.
Innovation Solution
A copper etchant formulation comprising hydrogen peroxide, sulfuric acid, an aromatic compound with a hydroxyl or carboxy group bonded to a benzene ring, and a controlled concentration of chlorine ions, along with optional triazoles, is used to stabilize the etching process and maintain smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sulfuric acid hydrogen peroxide-based etchant is used, then etching capability is achieved, but smoothness of copper surface after etching deteriorates
Solution Approach 1:
The patent introduces a novel aromatic compound with specific molecular structure (containing electron-donating groups like hydroxyl or amino groups attached to aromatic rings) to change the chemical parameters of the etchant system. This compound modifies the etching mechanism to produce smoother copper surfaces with stable morphology even after continuous etching operations, directly addressing the smoothness and stability problem
Solution Approach 2:
The patent creates a composite etchant formulation by combining sulfuric acid, hydrogen peroxide, and the novel aromatic compound. This composite chemical system leverages the oxidizing power of hydrogen peroxide, the acidic etching capability of sulfuric acid, and the surface-smoothing effect of the aromatic compound to achieve both effective etching and smooth surface finish
2Productivity
If continuous etching treatment is performed, then productivity is improved, but smoothness of copper surface deteriorates
Solution Approach 1:
The patent enables continuous etching operations by formulating a stable etchant composition that maintains consistent performance over time. The aromatic compound ensures that the etching action remains controlled and uniform throughout continuous processing, preventing surface roughening that typically occurs with prolonged or repeated etching cycles
Solution Approach 2:
The introduction of the aromatic compound changes the kinetic parameters of the etching reaction, creating a more stable and controllable etching process that can be sustained continuously without degradation of surface quality
3Manufacturing precision
If etchant removes seed layer, then wiring formation is achieved, but side etching of copper wiring occurs
Solution Approach 1:
The patent achieves selective etching by creating an etchant environment that differentiates between the seed layer and the finished copper wiring. The aromatic compound appears to provide preferential protection to the wiring surfaces while allowing removal of the seed layer, thereby minimizing side etching and preserving wiring shape accuracy
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 etchant effectively maintains a stable and highly smooth copper surface even after multiple etching treatments, reducing side etching and ensuring suitable etching rates, thus preserving the integrity of copper wiring.
Implementation Method 1
hydrogen peroxide, sulfuric acid, an aromatic compound, and a chlorine ion
Implementation Method 2
hydrogen peroxide, sulfuric acid, an aromatic compound, and a chlorine ion
Implementation Method 3
a chlorine ion, wherein the aromatic compound has a structure in which a hydroxyl group and/or a carboxy group is bonded to a benzene ring
Data Source
AI summary
A problem is to provide a copper etchant capable of stably maintaining smoothness after etching. As means for solving the problem, the etchant contains hydrogen peroxide, sulfuric acid, an aromatic compound, and a chlorine ion, in which the aromatic compound has a structure in which a hydroxyl group and/or a carboxy group is bonded to a benzene ring.