Selective Copper Seed Layer Etching Composition
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Solution Overview
Problem
Existing methods for removing copper seed layers in wiring board fabrication, such as SAP, M-SAP, and ETS processes, often result in reduced height and width of copper wiring and loss of rectangularity in the wiring cross-section.
Innovation Solution
An etching composition comprising hydrogen peroxide, sulfuric acid, an azole or its salt, a glycol ether, a halide ion, and water, with specific ratios and concentrations, is used to selectively etch the copper seed layer while minimizing thinning and maintaining rectangularity of the copper wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to remove copper seed layer, then the copper seed layer can be removed, but the height and width of copper wiring are reduced and rectangularity of wiring cross-section is lost
Solution Approach 1:
The patent applies parameter changes by carefully controlling the composition ratios and concentrations of etching agents (hydrogen peroxide, sulfuric acid, acetic acid) and additives (azole compounds, halide ions, glycol ethers) to achieve selective etching. By adjusting these chemical parameters, the etching rate for copper seed layer is optimized while minimizing etching of copper wiring, thus preserving wiring dimensions and rectangularity while removing the seed layer
Solution Approach 2:
The patent uses intermediary substances (azole compounds, halide ions, and glycol ethers) that mediate the etching process. These intermediaries selectively interact with the copper seed layer to enhance etching selectivity, allowing the copper seed layer to be removed while protecting the copper wiring from excessive etching, thereby maintaining wiring integrity and cross-sectional rectangularity
2Productivity
If etching is performed to remove copper seed layer, then the copper wiring pattern can be formed, but side etching and top surface etching occur reducing fabrication precision
Solution Approach 1:
The patent optimizes etching parameters including the ratios of hydrogen peroxide to sulfuric acid to acetic acid, concentrations of azole compounds (0.01-5 mass%), halide ion concentrations (10-1000 ppm), and process temperature (20-40°C) to achieve high etching rate for copper seed layer while minimizing side etching and top surface etching of copper wiring, thus improving both productivity and manufacturing precision
Solution Approach 2:
The patent employs intermediary compounds (azole compounds, halide ions, glycol ethers) that selectively accelerate the etching of copper seed layer while inhibiting etching of copper wiring. These intermediaries act as mediators that differentiate between the two copper structures, enabling high etching rates for seed layer removal while protecting the finished wiring pattern from damage
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 etching composition effectively removes the copper seed layer while preserving the dimensions and shape of the copper wiring, ensuring high precision and compatibility with miniaturization in wiring board production.
Implementation Method 1
hydrogen peroxide (A); sulfuric acid (B)... the ratio of the hydrogen peroxide (A) to the sulfuric acid (B) is 2 or greater in terms of a molar ratio
Implementation Method 2
sulfuric acid (B)... the content of the sulfuric acid (B) is 0.5-5 mass % based on the total amount of the etching composition
Data Source
AI summary
The present invention relates to an etching composition for selectively etching a copper seed layer from a substrate that has a copper wiring pattern and the copper seed layer. An etching composition according to the present invention is used for the purpose of selectively etching a copper seed layer from a substrate that has a copper wiring pattern and the copper seed layer, and is characterized by containing (A) hydrogen peroxide, (B) sulfuric acid, (C) an azole or a salt thereof, (D) a glycol ether, (E) a halide ion and (F) water, while being also characterized in that: the content of the hydrogen peroxide (A) is 0.1 to 10% by mass based on the total amount of the etching composition; the content of the sulfuric acid (B) is 0.5 to 5% by mass based on the total amount of the etching composition; the ratio of the hydrogen peroxide (A) to the sulfuric acid (B) is 2 or more in terms of the molar ratio; and the content of the halide ion (E) is 0.01 to 3 ppm based on the total amount of the etching composition.