SiGe Etching Composition for High-Ge Selectivity and Surface Flatness
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Solution Overview
Problem
The existing etching solutions for semiconductor manufacturing, particularly for gate-all-around transistors, exhibit insufficient etching selectivity towards silicon germanium with higher germanium concentrations, leading to poor performance and surface damage during the etching process.
Innovation Solution
An etching solution comprising an oxidizing agent, fluoride, a compound represented by a specific formula, carboxylic acid as a solvent, and water, which provides enhanced etching selectivity by preferentially etching silicon germanium with higher germanium concentrations while minimizing damage to regions with lower germanium concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching solutions are used to etch silicon germanium, then etching process can be performed, but etching selectivity towards silicon germanium with higher germanium concentrations is insufficient
Solution Approach 1:
The etching solution changes chemical parameters by incorporating specific organic acids (acetic acid, propionic acid, or butyric acid) with controlled concentrations (1-50 mass%), along with oxidizing agents and fluorides, to achieve differential etching rates between SiGe regions with different germanium concentrations, thereby improving etching selectivity while maintaining surface flatness
Solution Approach 2:
The etching solution uses a composite chemical formulation combining organic acids, oxidizing agents (nitric acid, hydrogen peroxide, or ammonium persulfate), and fluorides (hydrogen fluoride or hexafluorosilicic acid) to create a synergistic effect that enables selective etching of high-germanium SiGe while preserving low-germanium SiGe regions, resolving the contradiction between selectivity and surface integrity
2Manufacturing precision
If etching solution with high selectivity is used, then etching precision is improved, but etching rate may be reduced
Solution Approach 1:
The solution adjusts chemical concentration parameters to optimize both selectivity and rate: organic acid concentration (1-50 mass%), oxidizing agent concentration (0.1-10 mass%), and fluoride concentration (0.1-10 mass%) are carefully balanced to achieve high etching selectivity (greater than 10:1) while maintaining practical etching rates for manufacturing
Solution Approach 2:
The etching solution exhibits local quality by reacting differently with regions of varying germanium concentration: it aggressively etches high-germanium SiGe regions (x ≥ 0.5) while having minimal effect on low-germanium SiGe regions (x < 0.5), enabling selective removal without compromising overall processing efficiency
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 achieves excellent etching selectivity and rate for Si1-xGex with higher germanium concentrations, maintaining surface flatness and reducing surface roughness, thereby improving the manufacturing process for semiconductor devices like gate-all-around transistors.
Implementation Method 1
an etching composition which selectively dissolves silicon germanium over silicon and which contains an oxidizing agent (A) and an organic acid (B)
Implementation Method 2
selectively dissolves silicon germanium over silicon
Data Source
AI summary
An etching solution having excellent etching selectivity, an etching method using the etching solution, and a method for manufacturing a semiconductor device using the etching solution. The etching solution includes an oxidizing agent, a fluoride, a compound represented by the following formula (1), a carboxylic acid as a solvent, and water,and R1 and R2 each independently represents a hydrogen atom, a halogen atom, an alkyl group, a fluoroalkyl group, or an alkoxy group, and R3 and R4 each independently represents a halogen atom, a hydroxy group, an alkyl group, a fluoroalkyl group, or an alkoxy group.