SiGe Etching Composition With High Dielectric Selectivity
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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 performance and require additional costly protective steps.
Innovation Solution
An etching composition comprising fluorine-containing acids, oxidizing agents, organic acids, polymerized naphthalene sulfonic acid, amines, and water is used to selectively remove SiGe, minimizing damage to adjacent materials and improving etching selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etching process is used on SiGe layer, then etching speed is improved, but damage to gate insulating layer and semiconductor substrate occurs
Solution Approach 1:
The patent changes the chemical parameters of the etching process by using a specifically formulated liquid etching composition containing fluorine-containing acids, organic acids, and other additives. This chemical formulation enables selective etching of SiGe at controlled rates while minimizing damage to surrounding materials, resolving the contradiction between etching speed and damage prevention.
Solution Approach 2:
The patent introduces a selectively formulated etching composition as an intermediary medium that preferentially reacts with SiGe while being less aggressive toward gate insulating layers and substrates. This intermediary enables the etching process to proceed without directly damaging sensitive surrounding materials.
2Reliability
If additional protective steps are employed to avoid etching damage, then device yield and performance are improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent extracts and removes the need for additional protective steps by incorporating selective etching capability directly into the etching composition itself. The formulated solution provides inherent selectivity that protects surrounding materials without requiring separate protective layer deposition or removal steps, thereby maintaining device yield while reducing manufacturing complexity and cost.
3Reliability
If high selectivity etching of SiGe is achieved, then device yield is improved, but etching process complexity increases
Solution Approach 1:
The patent merges multiple functions into a single etching composition formulation that provides both high etching speed for SiGe and inherent selectivity to protect surrounding materials. By combining these capabilities in one process step with a carefully formulated chemical composition, the patent achieves high device yield without increasing process complexity.
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 SiGe/dielectric material etch selectivity and low etch rates for SiGe doped with boron, reducing substrate damage and enhancing device performance while minimizing additional manufacturing costs.
Implementation Method 1
an etching composition that includes a) at least one fluorine-containing acid, the at least one fluorine-containing acid including hydrofluoric acid or hexafluorosilicic acid; b) at least one oxidizing agent
Implementation Method 2
c) at least one organic acid or an anhydride thereof, the at least one organic acid including formic acid, acetic acid, propionic acid, or butyric acid; d) 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 germanium (SiGe) from a semiconductor substrate as an intermediate step in a multistep semiconductor manufacturing process.