Semiconductor Etching Composition for Selective Si Over SiGe
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Solution Overview
Problem
Current semiconductor etching processes struggle to selectively etch silicon (Si) from substrates containing both Si and silicon germanium (SiGe), as the etching rate of SiGe is high and the ratio of Si to SiGe etching rates is low, making it difficult to selectively etch Si.
Innovation Solution
A composition comprising a quaternary ammonium salt with a hydroxyl group, a polar organic solvent, a nitrogen-containing compound, and water, with specific mass ratios and content percentages, is used to suppress SiGe etching and enhance the Si to SiGe etching rate ratio, including the use of dimethylbis(2-hydroxyethyl)ammonium hydroxide, dimethyl sulfoxide, and hydrazine, which are added to ultrapure water to form a semiconductor treatment solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching composition is used, then etching rate of Si is improved, but etching rate of SiGe increases simultaneously, resulting in low selectivity
Solution Approach 1:
The invention changes the chemical parameters of the etching composition by incorporating specific compounds (quaternary ammonium salt with hydroxyl group, polar organic solvent, and nitrogen-containing compound) in controlled concentrations. This modifies the etching chemistry to selectively suppress SiGe etching while maintaining Si etching capability, achieving high selectivity without sacrificing overall etching productivity
Solution Approach 2:
The invention uses a composite etching composition containing multiple carefully selected components working together: quaternary ammonium salt (e.g., TMAH) as base etchant, polar organic solvent (e.g., DMSO) to modify etching behavior, and nitrogen-containing compound (e.g., hydrazine) as selective inhibitor. This composite formulation creates synergistic effects that achieve selective Si etching while suppressing SiGe etching
2Speed
If etching composition targets Si etching, then Si etching rate is increased, but SiGe etching rate remains high, making selective etching difficult
Solution Approach 1:
The nitrogen-containing compound acts as an intermediary substance that selectively interacts with SiGe to suppress its etching. This compound mediates between the base etchant and SiGe, preventing unwanted reaction while allowing Si etching to proceed at high rate, thus eliminating the harmful effect of SiGe etching without reducing Si etching speed
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 effectively suppresses SiGe etching while increasing the Si to SiGe etching rate ratio, allowing for selective etching of Si, as demonstrated by reduced SiGe etching rates and enhanced Si/SiGe ratio in experimental results.
Implementation Method 1
a quaternary ammonium salt having a hydroxyl group
Implementation Method 2
a polar organic solvent
Implementation Method 3
at least one nitrogen-containing compound selected from the group consisting of a compound represented by Formula (1) which will be described later, a compound represented by Formula (2) which will be described later, and salts thereof
Data Source
AI summary
The present invention provides a composition for treating a semiconductor in which etching of silicon germanium is suppressed and a ratio of an etching rate of silicon to an etching rate of silicon germanium is large. In addition, the present invention provides a method for treating an object to be treated using a composition for treating a semiconductor. The composition for treating a semiconductor according to the present invention is a composition for treating a semiconductor including a quaternary ammonium salt having a hydroxyl group, a polar organic solvent, at least one nitrogen-containing compound selected from the group consisting of a compound represented by Formula (1), a compound represented by Formula (2), and salts thereof, and water, in which the mass ratio of the nitrogen-containing compound to the quaternary ammonium salt is 0.00001 to 0.1.