Copper Etching Solution for Continuous Side-Etch Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing etching solutions for copper wiring in printed wiring boards suffer from significant side etching, leading to undesirable narrowing of the copper wiring width, especially in fine patterns, and fail to maintain effective side etching suppression during continuous use due to decomposition of aliphatic heterocyclic compounds.
Innovation Solution
An etching solution containing an acid, oxidizing metal ion, bromide ion, piperazine compound, and imidazole compound, with specific concentrations and combinations to stabilize the piperazine compound and maintain side etching suppression, supplemented by a replenishment solution to sustain performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional etching solutions (iron chloride-based, copper chloride-based, or alkaline) are used, then etching process is simple and cost-effective, but side etching occurs causing copper wiring width to narrow and linearity to deteriorate
Solution Approach 1:
The patent changes the chemical parameters of the etching solution by introducing specific heterocyclic compounds (azole compounds with 5-membered rings containing nitrogen, such as imidazole, triazole, or tetrazole) into conventional etching solutions. This chemical parameter modification enables the solution to suppress side etching while maintaining etching capability, thereby improving copper wiring width precision without sacrificing manufacturing simplicity
Solution Approach 2:
The patent creates a composite etching solution by combining conventional etching agents (iron chloride, copper chloride, or alkaline solutions) with heterocyclic compounds. This composite formulation integrates the etching function of conventional solutions with the side etching suppression capability of heterocyclic compounds, achieving both manufacturing ease and high precision
2Manufacturing precision
If aliphatic heterocyclic compounds (e.g., piperazine) are added to suppress side etching, then side etching suppression and linearity maintenance are improved, but the compound decomposes during continuous use making solution management difficult
Solution Approach 1:
The patent changes the chemical structure parameter from aliphatic heterocyclic compounds to aromatic heterocyclic compounds (specifically 5-membered rings containing nitrogen). This structural parameter change fundamentally improves stability during continuous use while maintaining side etching suppression effectiveness, resolving the reliability issue without sacrificing manufacturing precision
3Reliability
If heteroaromatic compound with 5-membered heteroaromatic ring is added to suppress decomposition of aliphatic heterocyclic compound, then decomposition is partially suppressed, but no effective combination is described and sufficient side etching suppression cannot be maintained continuously
Solution Approach 1:
The patent merges the functions of multiple compounds into a single effective formulation by combining heterocyclic compounds (5-membered rings containing nitrogen) with conventional etching agents at specifically optimized concentrations. This merging achieves both decomposition suppression and effective side etching suppression that neither component can achieve alone, maintaining manufacturing precision during continuous use
Solution Approach 2:
The patent optimizes the concentration parameter of heterocyclic compounds to 0.01-100 g/L, which is the critical threshold for maintaining both stability and effectiveness. This parameter optimization ensures sufficient side etching suppression while preventing decomposition during continuous use
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 suppresses side etching in copper wiring, maintaining linearity and uniformity even with continuous use, and allows for the formation of fine copper wiring patterns without significant degradation.
Implementation Method 1
an oxidizing metal ion
Implementation Method 2
a bromide ion
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An object of the present invention is to provide an etching solution, a replenishment solution, and a method for forming a copper wiring, in which an original function of an etching solution such as suppression of side etching is easily maintained. As a means for solving the problem of the present invention, there is disclosed a copper etching solution, in which the etching solution contains an acid, an oxidizing metal ion, a bromide ion, a compound having a piperazine skeleton, and an imidazole compound, and the compound having a piperazine skeleton is represented by the following general formula (1): In the formula, R1 and R2 each independently represent a hydrogen atom, an amino group-containing substituent, or a hydrocarbon derivative group having 1 to 10 carbon atoms wherein the hydrocarbon derivative group does not contain an amino group-containing substituent.