Semiconductor Cleaning Solution Recovery for Copper Ion Removal
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Solution Overview
Problem
Semiconductor devices using low-k or ultra-low-k porous inter-layer dielectric (ILD) layers and copper interconnects suffer from time-dependent dielectric breakdown (TDDB) due to copper ions reacting with cleaning solutions, leading to reliability issues and poor performance, as these ions are not effectively removed even after filtering, causing repeated use of cleaning solutions to degrade device properties.
Innovation Solution
A method and system for treating cleaning solutions to remove copper ions and polymer residues, allowing the solution to be reused without adversely affecting semiconductor devices, involving ion exchange or absorption methods using materials like polyethylene imine, activated carbon, or bacterial cells to reduce metal ion concentration, thereby minimizing their absorption by the ILD layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cleaning solutions are repeatedly used to reduce cleaning and manufacturing cost, then manufacturing cost is reduced, but copper ions accumulate in the cleaning solution causing time dependent dielectric breakdown (TDDB) and reducing device reliability
Solution Approach 1:
The patent implements a cleaning solution recovery system where used cleaning solutions are collected, treated to remove copper ions and polymer residues through filtration and chemical treatment, and then reused. This prevents copper ion accumulation that causes TDDB while reducing the need for continuous disposal and replacement of cleaning solutions, thereby maintaining device reliability and reducing manufacturing costs.
Solution Approach 2:
The patent introduces an intermediary treatment system between the cleaning process and solution reuse. This system includes filtration devices and chemical treatment agents that remove harmful copper ions and polymer residues from the cleaning solution, acting as a mediator that enables safe reuse of the cleaning solution without compromising device reliability.
2Manufacturing precision
If cleaning solutions are filtered to remove polymer residues, then cleaning effect is maintained, but copper ions remain in the solution causing TDDB and affecting device reliability
Solution Approach 1:
The patent segments the cleaning solution treatment process into distinct stages: first filtering to remove polymer residues, then treating to remove copper ions through chemical agents or advanced filtration. This segmentation allows each treatment step to focus on specific contaminants, ensuring both cleaning effectiveness and removal of TDDB-causing copper ions.
Solution Approach 2:
The patent introduces copper ion removal agents or advanced filtration systems as intermediary treatment steps after standard filtration. These intermediaries specifically target copper ions that standard filtration cannot remove, preventing TDDB while maintaining the cleaning effectiveness achieved by polymer residue removal.
3Productivity
If copper ions are not removed from cleaning solutions, then cleaning solution can be reused, but copper ions are absorbed by the porous ILD layer causing TDDB and reducing device performance
Solution Approach 1:
The patent implements a comprehensive recovery system that removes copper ions from cleaning solutions through chemical treatment agents or specialized filtration media. This enables the cleaning solution to be reused multiple times without copper ion accumulation, preventing ILD layer absorption and TDDB while maintaining high productivity through extended solution life.
Solution Approach 2:
The patent changes the chemical parameters of the cleaning solution by introducing copper ion chelating agents or adjusting pH levels to prevent copper ion absorption by the porous ILD layer. These parameter changes transform the cleaning solution into a form that can be safely reused without causing TDDB, thereby improving productivity while protecting device performance.
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 treated cleaning solution maintains acceptable metal ion levels, reducing the risk of TDDB and ensuring the reliability and performance of semiconductor devices, allowing for repeated use without compromising device integrity.
Implementation Method 1
A first cleaning solution can be used to remove the photoresist polymer residues from the semiconductor device to produce a second cleaning solution containing one or more of copper ions and polymer residues
Implementation Method 2
involving ion exchange or absorption methods using materials like polyethylene imine, activated carbon, or bacterial cells to reduce metal ion concentration
Implementation Method 3
involving ion exchange or absorption methods using materials like polyethylene imine, activated carbon, or bacterial cells to reduce metal ion concentration
Data Source
AI summary
Various embodiments provide methods and systems for making and/or cleaning semiconductor devices. In one embodiment, a semiconductor device can be formed including a metal layer and a photoresist polymer. During formation, the semiconductor device can be cleaned in a cleaning chamber by a first cleaning solution provided from a solution supply device. After this cleaning process, a second cleaning solution containing metal ions and/or polymer residues can be produced and processed in a solution processing device to at least partially remove the metal ions and/or polymer residues to produce a third cleaning solution for re-use. In an exemplary fabrication or cleaning system, the solution processing device may be configured connecting to either an inlet or an outlet of the cleaning chamber. After cleaning, the semiconductor device can be processed to include a metal plug or an interconnect wiring.