Sulfonic Acid Etchant Selective Metal Removal
Solution Overview
Problem
Current etching methods for semiconductor substrates struggle to selectively remove metal layers containing specific metals like nickel platinum, titanium, nickel, platinum, tungsten, and cobalt without damaging germanium-containing layers, especially in the context of miniaturization where precise etching is critical for maintaining the integrity of integrated circuits.
Innovation Solution
An etchant comprising a sulfonic acid compound, a halogen ion, nitric acid or nitric acid ion, an organic cation, and water is used, with specific concentrations and compositions that allow for selective etching of metal layers on semiconductor substrates, ensuring minimal damage to germanium-containing layers and maintaining excellent etching properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods (aqua regia, nitric acid + hydrochloric acid) are used, then metal layers can be removed, but germanium-containing layers are damaged and corrosion occurs
Solution Approach 1:
The patent changes the chemical composition parameters of the etching solution by introducing a sulfonic acid compound (specifically p-toluenesulfonic acid) as a key component, combined with nitric acid and hydrochloric acid in optimized ratios. This parameter change transforms the etching chemistry to achieve high selectivity for metal layers while preventing germanium layer corrosion, directly resolving the technical contradiction between etching effectiveness and germanium layer protection
Solution Approach 2:
The patent creates a composite etching solution comprising multiple chemical components (sulfonic acid compound, nitric acid, hydrochloric acid, and water) that work synergistically. The composite formulation combines the oxidizing power of nitric acid, the chloride complexing ability of hydrochloric acid, and the selective etching enhancement from the sulfonic acid compound, achieving both high metal removal rate and germanium layer protection simultaneously
2Productivity
If etching is performed to remove metal layers, then wiring and circuit features can be formed, but the etching process causes corrosion and defects in germanium silicide layers
Solution Approach 1:
The patent optimizes the concentration parameters of the etching solution components, specifically setting the sulfonic acid compound at 1-10 wt%, nitric acid at 5-20 wt%, and hydrochloric acid at 5-20 wt%. These parameter optimizations enable fast etching rates for metal layers while the sulfonic acid compound forms a protective effect on germanium silicide layers, maintaining both productivity and reliability
Solution Approach 2:
The sulfonic acid compound acts as an intermediary substance in the etching solution that mediates between the aggressive etching agents (nitric and hydrochloric acids) and the germanium silicide layer. It selectively enhances the etching of metal layers while forming a protective interaction with germanium silicide, preventing corrosion and maintaining layer integrity during the etching process
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 removes metal layers with a high selectivity ratio, preventing corrosion and defects in germanium silicide layers, thus ensuring the quality and performance of semiconductor substrates, particularly in the context of miniaturized integrated circuits.
Implementation Method 1
an etchant for a semiconductor process, comprising: a sulfonic acid compound; a halogen ion (halide ion); nitric acid or a nitric acid ion; an organic cation; and water
Implementation Method 2
exhibits excellent etching characteristics, an etching method using the same, and method for manufacturing a semiconductor substrate product
Data Source
AI summary
Provided is an etchant for a semiconductor process, which contains a sulfonic acid compound, a halogen ion, nitric acid or a nitric acid ion, an organic cation, and water.