Semiconductor Residue Removal via Chelating Amine Salts
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Solution Overview
Problem
Current chemical solutions for removing residues after dry etching and ashing in semiconductor manufacturing, particularly for Cu/low-k multilayer interconnect structures, often cause Cu corrosion and damage to low-k films, leading to cracking and roughness of the Cu surface, and are inefficient in completely removing residues in a short time.
Innovation Solution
A chemical solution comprising an amine salt of a monocarboxylic acid and/or a salt of a polycarboxylic acid that forms a 7- or more-membered ring chelate with copper, combined with water, with specific pH ranges to inhibit Cu corrosion and prevent damage to low-k films, allowing for the complete removal of residues without causing cracking or roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If commercially available polymer-removing solutions or etchants are used to remove residues and Cu oxide films, then residues can be removed, but Cu corrosion occurs and low-k films are damaged
Solution Approach 1:
The invention changes the chemical parameters of the cleaning solution by specifying precise pH ranges (pH 2-4 for first cleaning solution, pH 7-11 for second cleaning solution) and component concentrations. This parameter optimization allows effective residue and Cu oxide film removal while controlling the aggressiveness of the solution to prevent Cu corrosion and low-k film damage.
Solution Approach 2:
The cleaning process is segmented into two distinct stages: first cleaning with an acidic solution (pH 2-4) to remove residues and Cu oxide films, then second cleaning with a basic solution (pH 7-11) to neutralize and clean the Cu surface. This segmentation allows each stage to target specific contaminants without causing harmful side effects.
2Reliability
If strong acids like hydrochloric acid or fluoric acid are used to remove residues, then residues can be removed, but Cu corrosion is caused due to high H+ concentration
Solution Approach 1:
The invention changes the pH parameter from highly acidic (which causes corrosion) to mildly acidic (pH 2-4) for the first cleaning solution, and then to basic (pH 7-11) for the second cleaning solution. This parameter control reduces H+ concentration to prevent Cu corrosion while maintaining residue removal effectiveness through optimized acid component selection and concentration.
3Productivity
If dry etching and ashing processes are used to form Cu/low-k multilayer interconnect structures, then interconnect delay is reduced, but residues remain on the substrate after processing
Solution Approach 1:
The invention introduces chemical cleaning solutions as intermediary substances between the dry etching/ashing processes and the final Cu plating step. These cleaning solutions act as mediators that remove residues and Cu oxide films formed during dry processing, ensuring substrate cleanliness without requiring additional mechanical or thermal processing steps.
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 removes residues after a dry process without causing Cu corrosion or damage to low-k films, maintaining the integrity of the Cu surface and preventing cracking and roughness, while ensuring efficient processing times.
Implementation Method 1
an amine salt of a monocarboxylic acid and/or a salt of a polycarboxylic acid that forms a 7- or more-membered ring chelate with copper
Data Source
AI summary
A residue-removing solution for removing residues after a dry process, which includes an amine salt of a monocarboxylic acid and/or a salt of a polycarboxylic acid that forms a 7- or more-membered ring chelate with copper, and water, the residue-removing solution containing aqueous solution (A) or (B) as described herein. Also disclosed is a method for removing residues present on a semiconductor substrate after dry etching and/or ashing. Further, a method for manufacturing semiconductor devices is further disclosed, which includes subjecting a semiconductor substrate having Cu as an interconnect material, and a low dielectric constant film as an interlayer dielectric material, to dry etching and/or ashing; and bringing the processed semiconductor substrate into contact with the above residue-removing solution.