Selective SiGe Etching Composition for Adjacent Material Protection
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Solution Overview
Problem
The semiconductor industry faces challenges in selectively etching silicon germanium (SiGe) without damaging adjacent materials like gate insulating layers and semiconductor substrates during the plasma etching process, which can impact device yield and performance.
Innovation Solution
An etching composition comprising fluorine-containing acids, oxidizing agents, organic acids, polymerized naphthalene sulfonic acids, amines, and water is used to selectively remove SiGe relative to hard mask layers and low-k dielectric layers, minimizing damage to adjacent materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etching process is used on SiGe layer, then etching efficiency is improved, but damage to gate insulating layer and semiconductor substrate occurs
Solution Approach 1:
The patent changes the etching process parameters by switching from plasma etching to chemical etching using a specifically formulated composition containing fluorine-containing acid, oxidizing agent, and organic acid. This parameter change enables selective etching of SiGe at controlled rates while minimizing damage to gate insulating layers and substrates, resolving the contradiction between etching efficiency and material damage.
Solution Approach 2:
The patent introduces an intermediary etching composition that selectively interacts with SiGe while being less aggressive toward adjacent materials. The composition acts as a mediator between the SiGe layer and the surrounding structures, enabling removal of SiGe with reduced harmful effects on gate insulating layers and substrates through its tailored chemical properties.
2Reliability
If additional protective device manufacturing steps are employed to avoid etching damage, then device yield is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the protective function from separate manufacturing steps and integrates it into the etching composition itself. By formulating a selective etching solution that inherently protects adjacent materials while etching SiGe, the need for additional protective steps is eliminated, improving device yield without increasing manufacturing complexity.
Solution Approach 2:
The etching composition performs multiple functions simultaneously: it etches SiGe effectively while also protecting gate insulating layers and substrates from damage. This multi-functionality consolidates what would otherwise require separate protective steps into a single process, reducing manufacturing complexity while maintaining high device yield.
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 SiGe while minimizing the removal of other materials, thereby enhancing device yield and performance by reducing etching damage and additional manufacturing steps.
Implementation Method 1
a) at least one fluorine-containing acid, the at least one fluorine-containing acid including hydrofluoric acid or hexafluorosilicic acid
Implementation Method 2
b) at least one oxidizing agent
Data Source
AI summary
The present disclosure is directed to etching compositions that are useful for, e.g., selectively removing silicon germanium (SiGe) from a semiconductor substrate as an intermediate step in a multistep semiconductor manufacturing process.