Selective Hard Mask Etching for Low-k and Copper Interconnects
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Solution Overview
Problem
Current cleaning compositions used in semiconductor manufacturing are inadequate for efficiently removing post-etch or post-ash residues and etching layers such as TiN, Ta, TaN, Al, and HfOx without damaging low-k materials, copper, cobalt, or tungsten.
Innovation Solution
A cleaning composition comprising solubilizers, corrosion inhibitors, polar non-protogenic organic solvents, and water, combined with oxidants, is used to selectively remove post-etch residues and etch layers like TiN and Al compounds on semiconductor substrates, while preserving low-k materials and metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning compositions are used to remove post-etch residues and etch aluminum compounds, then etching effectiveness is improved, but low-k materials, copper, cobalt, and tungsten are damaged or removed
Solution Approach 1:
The patent modifies the chemical parameters of the cleaning composition by incorporating specific solubilizers (compounds of formula I), corrosion inhibitors (benzotriazoles), polar non-protogenic organic solvents, and oxidants in controlled concentrations. These parameter changes enable the composition to selectively etch aluminum compounds and remove residues while maintaining stability towards low-k materials, copper, cobalt, and tungsten, thus achieving high etching selectivity without damaging underlying materials
Solution Approach 2:
The patent introduces corrosion inhibitors (specifically benzotriazole compounds) and stabilizers as intermediary substances that mediate between the oxidants and the metal layers. These intermediaries protect the metal surfaces from unwanted oxidation and damage while allowing the etching process to proceed on the aluminum compounds, thereby preventing harmful effects on underlying materials
2Manufacturing precision
If multi-step processes are used to selectively remove hard mask and etch-stop layer, then selectivity is improved, but processing time and complexity increase
Solution Approach 1:
The patent merges multiple functions into a single cleaning composition that can simultaneously remove post-etch residues, etch aluminum compounds, and protect underlying materials. By combining solubilizers, corrosion inhibitors, polar solvents, and oxidants in one formulation, the patent achieves what previously required multiple separate process steps, thereby reducing processing time while maintaining high selectivity
Solution Approach 2:
The cleaning composition is designed with multi-functionality to perform several tasks simultaneously: removing organic and inorganic residues, etching aluminum compounds and aluminum oxide, protecting metal layers through corrosion inhibition, and stabilizing against unwanted reactions. This universal composition eliminates the need for multiple specialized process steps, reducing both time and complexity
3Productivity
If oxidants are added to enhance etching capability, then etching rate is improved, but stability of the composition deteriorates
Solution Approach 1:
The patent incorporates corrosion inhibitors and stabilizers into the cleaning composition before the etching process begins. These preliminary additives pre-establish protective mechanisms that prevent unwanted oxidation and decomposition of the composition, allowing oxidants to be present at effective concentrations without compromising overall composition stability during storage and use
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 achieves a controlled and specific etching of targeted layers, effectively removing residues and etching layers in a single step, even for sub-7 nm structures, without compromising underlying materials.
Implementation Method 1
for oxidative etching or partially oxidative etching of a layer or mask comprising or consisting of a material selected from the group consisting of TiN, Ta, TaN, Al and HfOx and/or a layer or mask comprising or consisting of a material selected from the group consisting of tungsten carbide (WCx) and tungsten nitride (WNx)
Implementation Method 2
for removing post-etch or post-ash residue from the surface of a semiconductor substrate
Implementation Method 3
for removing from the surface of a semiconductor substrate a layer comprising an aluminium compound
Data Source
AI summary
The use of a cleaning composition in combination with one or more oxidants is described for removing post-etch or post-ash residue from the surface of a semiconductor substrate and/or for oxidative etching or partially oxidative etching of a layer or mask comprising or consisting of a material selected from the group consisting of TiN, Ta, TaN, Al and HfOx and/or a layer or mask comprising or consisting of a material selected from the group consisting of tungsten carbide (WCx) and tungsten nitride (WNx), and/or for removing from the surface of a semiconductor substrate a layer comprising an aluminium compound. Further is described said cleaning composition and a use of said cleaning composition for removing post-etch or post-ash residue from the surface of a semiconductor substrate. Under a further aspect, it is described a wet-etch composition comprising said cleaning composition and one or more oxidants as well as the use of said wet-etch composition. A process for the manufacture of a semiconductor device from a semiconductor substrate and a kit comprising said cleaning composition and one or more oxidants are also described.