Damascene Cleaning Solution for Semiconductor Residue Removal
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Solution Overview
Problem
The dual damascene process in semiconductor manufacturing faces issues with surface damage, copper loss, and increased dielectric constant due to polymerization reactions and fluorine-containing gas interactions, leading to reliability concerns and profile changes in the semiconductor device.
Innovation Solution
A cleaning solution comprising a fluorine-containing compound, an inorganic acid, a chelating agent with a carboxylic group, and water is used to remove residues and prevent damage, including hydrofluoric acid, sulfuric acid, ammonium fluoride, oxalic acid, triethanolamine, and ethylenediaminetetraacetic acid, which effectively addresses surface damage and dielectric layer integrity during the post-etch cleaning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fluorine-containing gases are used for etching the dielectric layer, then the dielectric layer can be precisely etched, but titanium fluoride residues are formed on the TiN hard mask layer surface causing profile changes and reliability reduction
Solution Approach 1:
The patent converts the harmful fluorine-containing residues into removable compounds by introducing a fluorine-containing cleaning solution. The fluorine in the cleaning solution reacts with the titanium fluoride residues to form volatile or water-soluble compounds that can be easily removed, thereby converting the harmful residues into beneficial removable substances.
Solution Approach 2:
The cleaning solution acts as an intermediary between the harmful titanium fluoride residues and the removal process. The solution contains fluorine-containing compounds that specifically react with titanium fluoride to form intermediate compounds that can be washed away, facilitating the removal of residues without directly damaging the underlying structures.
2Object-generated harmful factors
If post-etch cleaning process is performed to remove residues, then surface cleanliness is improved, but copper loss and dielectric layer damage occur
Solution Approach 1:
The patent carefully controls the parameters of the cleaning solution including fluorine compound concentration (0.01-0.5 wt%), inorganic acid concentration (1-5 wt%), pH value, and temperature to achieve effective residue removal while minimizing damage to copper and dielectric layers. By optimizing these parameters, the cleaning process becomes selective for residues rather than underlying structures.
Solution Approach 2:
The cleaning solution exhibits selective action with different effectiveness on different materials. It is highly effective at removing titanium fluoride residues while being gentle on copper and dielectric layers. This local quality difference allows the same cleaning solution to remove harmful residues without damaging the structures that need to be preserved.
3Object-generated harmful factors
If conventional cleaning solutions are used to remove polymer residues, then organic polymers can be removed, but dielectric constant increases and dielectric layer swells
Solution Approach 1:
The patent uses fluorine-containing compounds that specifically target and break down polymer residues into removable fragments without causing swelling or structural changes to the dielectric layer. The fluorine atoms react with the polymer chains to form volatile or water-soluble compounds that can be easily removed, converting the harmful polymer residues into beneficial removable substances without affecting dielectric properties.
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 cleaning solution effectively removes residues, prevents copper loss, and maintains dielectric layer integrity, enhancing the reliability of semiconductor devices by avoiding profile changes and bridging between dual damascene structures.
Implementation Method 1
the reactive gases used for etching the dielectric layer are mostly fluorine-containing gases. These fluorine-containing gases may react with the TiN hard mask layer to produce titanium fluoride (TiFx) on the surface of the device
Implementation Method 2
The cleaning solution includes 0.01-0.5 wt % of a fluorine containing compound; 1-5 wt % of an inorganic acid
Implementation Method 3
a chelating agent containing a carboxylic group
Data Source
AI summary
A cleaning solution is provided. The cleaning solution includes a fluorine containing compound, an inorganic acid, a chelating agent containing a carboxylic group and water for balance. The content of the fluorine containing compound is 0.01-0.5 wt % of. The content of the inorganic acid is 1-5 wt %.