Silicon Etching Composition for High-Selectivity Sacrificial Layer Removal
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Solution Overview
Problem
The semiconductor industry faces challenges in selectively etching silicon in the presence of other materials like metal conductors, gate materials, and low-k dielectric layers, which affects device yield and performance due to the similarity of these materials and the need for precise etching processes.
Innovation Solution
An etching composition comprising quaternary ammonium hydroxide, alkanolamine, SiGe corrosion inhibitors, polymerized naphthalene sulfonic acid, organic solvent, and water is used to selectively etch silicon, minimizing the removal of adjacent materials and optimizing etching performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching compositions are used to remove silicon sacrificial layers, then silicon etching is achieved, but adjacent materials such as SiGe, SiN, metal conductors, and low-k dielectric layers are also inadvertently removed or damaged
Solution Approach 1:
The patent modifies the chemical composition parameters of the etching solution by incorporating specific inhibitors (SiGe corrosion inhibitor, SiN corrosion inhibitor, metal conductor corrosion inhibitor) and surfactants at controlled concentrations. These parameter changes enable the etching process to selectively remove silicon while protecting adjacent materials, achieving high etching selectivity without damaging surrounding structures
Solution Approach 2:
The patent introduces intermediary substances (corrosion inhibitors and surfactants) that act as mediators between the etching composition and adjacent materials. These intermediaries form protective complexes or adsorption layers on the surfaces of SiGe, SiN, metal conductors, and low-k dielectric layers, preventing direct contact and damage from the etching agents while allowing silicon etching to proceed
2Productivity
If the etching process is made more aggressive to increase etching speed, then productivity improves, but selectivity decreases and adjacent materials are affected
Solution Approach 1:
The patent optimizes the concentration parameters of etching agents and inhibitors to achieve a balanced etching rate. By adjusting the ratios of active etching components to protective inhibitors, the composition enables fast silicon etching while maintaining high selectivity, resolving the trade-off between productivity and precision
Solution Approach 2:
The patent creates a composite etching composition that combines multiple functional components: silicon etching agents, SiGe corrosion inhibitors, SiN corrosion inhibitors, metal conductor corrosion inhibitors, and surfactants. This composite formulation enables simultaneous achievement of high etching speed and high selectivity by integrating multiple functions in a single composition
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 composition achieves high selectivity in etching silicon relative to SiGe and other materials, enhancing device yield and performance by ensuring precise removal of silicon films without significantly affecting adjacent layers, thus improving the manufacturing process of semiconductor devices.
Implementation Method 1
at least one quaternary ammonium hydroxide or a salt thereof; b) at least one alkanolamine
Implementation Method 2
at least one quaternary ammonium hydroxide or a salt thereof; b) at least one alkanolamine
Implementation Method 3
at least one SiGe corrosion inhibitor comprising 11-mercaptoundecylphosphoric acid, 8-mercaptooctanoic acid, 6-mercaptohexanoic acid, 12-mercaptododecanoic acid, 8-quinolinylboronic acid, 8-aminoquinoline, 8-quinolinecarboxylic acid, 8-quinolinethiol, 2,8-quinolinediol, 8-quinolinylacetic acid, 8-quinolinesulfonic acid, 2-methyl-8-quinolinol, 5-hydroxyquinoline, or 6-hydroxyquinoline
Implementation Method 4
at least one polymerized naphthalene sulfonic acid
Data Source
AI summary
The present disclosure is directed to etching compositions that are useful for, e.g., selectively removing silicon from a semiconductor substrate as an intermediate step in a multistep semiconductor manufacturing process.