Silicon Surface Cleaning Solution for Semiconductor Fabrication
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Solution Overview
Problem
The existing cleaning solutions for semiconductor devices are inadequate in selectively removing damaged portions of exposed silicon surfaces, leading to etching damage and corrosion of metal gate electrodes, particularly tungsten, which can deteriorate the electrical characteristics of semiconductor devices.
Innovation Solution
A cleaning solution comprising 0.01 to 1 wt% fluoric acid, 20 to 50 wt% oxidizer, and 50 to 80 wt% water, with acetic acid optionally included, is used to selectively clean the silicon surface, optimizing etch selectivity and reducing damage to silicon and tungsten layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If standard cleaning solutions (SC1 or diluted fluoric acid aqueous solution) are used for extended cleaning, then the silicon surface can be sufficiently cleaned, but the etch selectivity for silicon oxide layer decreases causing damage to the silicon surface
Solution Approach 1:
The patent changes the chemical composition parameters of the cleaning solution by introducing a specific organic acid (acetic acid, formic acid, or propionic acid) with controlled concentration (0.1-10 wt%), combined with fluoric acid and water in defined ratios. This parameter modification enables effective cleaning while reducing etching damage to the silicon oxide layer.
2Manufacturing precision
If standard cleaning solutions are used for cleaning, then the silicon surface can be cleaned, but metal gate electrodes (particularly tungsten) corrode during the cleaning process
Solution Approach 1:
The patent modifies the cleaning solution composition by incorporating specific organic acids (acetic acid, formic acid, or propionic acid) at controlled concentrations (0.1-10 wt%), which reduces the corrosiveness toward metal gate electrodes while maintaining cleaning effectiveness. The defined ratio of fluoric acid (0.1-5 wt%) and water further optimizes the chemical environment to protect metal structures.
3Productivity
If the silicon surface is not sufficiently cleaned, then the cleaning process time can be reduced, but the film quality of thin films formed during subsequent processes deteriorates
Solution Approach 1:
The patent optimizes the cleaning solution parameters including organic acid concentration (0.1-10 wt%), fluoric acid concentration (0.1-5 wt%), and water content (80-99.9 wt%) to achieve effective cleaning within shorter process times. The synergistic combination of these components enhances cleaning efficiency while protecting underlying structures, enabling both productivity improvement and quality maintenance.
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 effectively reduces etching damage and corrosion of tungsten gate electrodes while maintaining high etch selectivity for silicon, improving the quality of subsequent thin film formation and reducing surface roughness.
Implementation Method 1
a cleaning solution comprising 0.01 to 1 wt% fluoric acid, 20 to 50 wt% oxidizer, and 50 to 80 wt% water
Implementation Method 2
20 to 50 wt% oxidizer
Data Source
AI summary
A cleaning solution and methods of fabricating semiconductor devices using the same are provided. A cleaning solution used for cleaning a silicon surface and methods of fabricating a semiconductor device using the same are also provided. The cleaning solution may include 0.01 to 1 wt % of fluoric acid, 20 to 50 wt % of oxidizer and 50 to 80 wt % of water. The cleaning solution may further include 1 to 20 wt % of acetic acid. The cleaning solution may be used to clean a silicon surface exposed during fabrication processes of a semiconductor device. The cleaning solution may reduce damage of other material layers (e.g., a tungsten layer or a silicon oxide layer) and enable the silicon surface to be selectively etched.