SiGe Etching Solution for High Selectivity and Low Silicon Damage
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Solution Overview
Problem
Existing etching solutions for semiconductor manufacturing lack sufficient selectivity when etching silicon germanium (SiGe) compared to silicon, leading to poor etching performance and surface damage during the production of semiconductor devices like gate-all-around transistors.
Innovation Solution
An etching solution comprising an oxidizing agent, a fluoride, a specific compound represented by formula (1), and water, with the oxidizing agent constituting 20 mass % or more, which preferentially etches SiGe over silicon, enhancing etching selectivity and minimizing silicon surface damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching solutions are used to etch silicon germanium, then etching can proceed, but etching selectivity towards silicon germanium compared to silicon is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the etching solution by incorporating specific compounds (nitric acid, hydrogen peroxide, acetic acid, and a fluorinated compound) in optimized ratios. This chemical parameter modification enables selective etching of SiGe over Si by exploiting differences in their chemical reactivity with the solution components, achieving etching selectivity of 10 or more while minimizing silicon surface damage
Solution Approach 2:
The etching solution uses a composite chemical system combining multiple agents: oxidizing agents (nitric acid, hydrogen peroxide), organic acids (acetic acid), and fluorinated compounds. This composite approach creates synergistic effects where each component contributes to different aspects of the etching process - oxidation, complex formation, and selective dissolution - thereby achieving high selectivity and reduced harm to silicon surfaces
2Manufacturing precision
If etching selectivity is improved, then silicon surface damage is reduced, but etching rate may be affected
Solution Approach 1:
The patent optimizes concentration parameters of each component to achieve a balance between selectivity and etching rate. By adjusting the ratios of oxidizing agents, organic acids, and fluorinated compounds, the solution maintains high etching selectivity (10 or more) while ensuring sufficient etching rate for practical manufacturing applications
Solution Approach 2:
The etching solution maintains continuous effective action on SiGe through the synergistic mechanism where oxidizing agents continuously generate oxidized species, organic acids facilitate complex formation, and fluorinated compounds enable selective dissolution. This continuous action ensures sustained etching rate without compromising selectivity over extended processing times
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 for SiGe over Si, with etching rates of 5 nm/min or more for SiGe and 0.05 nm/min or less for Si, resulting in improved manufacturing processes with reduced silicon surface roughness.
Implementation Method 1
an etching solution containing: an oxidizing agent; a fluoride; a compound represented by the following formula (1); and water
Implementation Method 2
a fluoride
Data Source
AI summary
An etching solution, 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 formula (1) below, and water, a mass of the oxidizing agent is 20 mass % or more with respect to a mass of the etching solution,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.