UV Pre-Cleaning for Fluorine Residue Removal in Semiconductor Etching
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Solution Overview
Problem
The dry etching process in semiconductor manufacturing using fluorine-containing gases leads to the formation of fluorine-containing compounds on etched surfaces, which can react with water-based cleaning solutions to form hydrofluoric acid, causing low-k leakage defects and deteriorating the RC performance and breakdown voltage of semiconductor devices.
Innovation Solution
A pre-cleaning process using UV radiation is implemented to degrade and remove fluorine-containing compounds formed during etching, preventing the formation of hydrofluoric acid during subsequent cleaning, and a system combining etching, pre-cleaning, and cleaning chambers ensures better control and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry etching process using fluorine-containing gas is performed on ILD layer, then anisotropic etching and high selectivity are achieved, but fluorine-containing compounds are formed on etched surface causing low-k leakage defects
Solution Approach 1:
A pre-cleaning process using UV irradiation is performed before the main cleaning process to remove fluorine-containing compounds from the etched surface. This preliminary action prevents the formation of hydrofluoric acid during subsequent water-based cleaning, thereby avoiding low-k leakage defects while maintaining the etching selectivity benefits
Solution Approach 2:
UV irradiation is introduced as an intermediary step between etching and cleaning processes. The UV light activates and removes fluorine-containing compounds without directly contacting the etched surface with chemical reagents that could cause damage, serving as a safe mediator to eliminate harmful residues
2Ease of operation
If water-based cleaning solution is used to clean etched surface, then cleaning effectiveness is improved, but hydrofluoric acid is formed reacting with fluorine-containing compounds causing carbon depletion
Solution Approach 1:
The pre-cleaning process using UV irradiation removes fluorine-containing compounds before the water-based cleaning step. By eliminating the fluorine-containing compounds in advance, the subsequent water-based cleaning cannot form hydrofluoric acid, thus preventing carbon depletion while maintaining cleaning effectiveness
Solution Approach 2:
The UV irradiation process converts the harmful fluorine-containing compounds into removable volatile species. What would otherwise be harmful residues that react with water to form hydrofluoric acid are transformed into easily removable substances through UV activation, turning a potential harm into a beneficial removal mechanism
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
This approach effectively prevents low-k leakage defects and carbon depletion, enhancing the reliability and performance of semiconductor devices by ensuring complete removal of fluorine-containing compounds without enlarging surface pores, thus maintaining the integrity of the dielectric layer.
Implementation Method 1
a pre-cleaning process is performed by using UV radiation so as to remove the fluorine-containing compounds
Data Source
AI summary
A method for fabrication a semiconductor device and a system utilizing the same are provided. In the method for fabrication the semiconductor device, at first, a semiconductor structure having a metal conducting structure is provided. Next, a dielectric layer is deposited over the metal conducting structure. Then, an etching process is performed on the dielectric layer by using a fluorine-containing gas so as to form an opening, in which fluorine-containing compounds are formed on a surface of the opening during the etching process. And then, a pre-cleaning process is performed by using UV radiation so as to remove the fluorine-containing compounds. After the pre-cleaning process is performed, a cleaning process is performed to clean the surface of the opening.