Copper Line Cleaning via pH and Potential Difference Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional post-etch residue cleaning processes for copper lines in dual damascene processes often result in corrosion, leading to pitting and electrical property degradation due to the use of aqueous solutions.
Innovation Solution
A method involving a copper line divided into regions with different numbers of openings, where a potential difference is created during etching, and a cleaning solution with a specific pH value is used to remove residues without corroding the copper, following the relationship X (pH) and Y (potential difference) within defined ranges to maintain the copper in a non-corroded state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional aqueous solution is used for cleaning post-etch residues, then the residues can be removed, but corrosion occurs leading to pitting and electrical property degradation
Solution Approach 1:
The patent changes the chemical parameters of the cleaning solution by controlling pH value and potential difference within specific ranges defined by the mathematical relationship. This parameter control allows effective residue removal while preventing copper corrosion, resolving the contradiction between cleaning effectiveness and copper line integrity
Solution Approach 2:
The patent applies preliminary anti-action by establishing a protective potential difference across the copper line before and during the cleaning process. This pre-established electrical condition prevents corrosion from occurring during residue removal, countering the harmful effect before it can damage the copper structure
2Productivity
If a dry etching process is used to form openings, then the dielectric layer can be etched, but post-etch residues are formed on the dielectric layer
Solution Approach 1:
The patent extracts and removes the harmful post-etch residues from the dielectric layer surface through a controlled cleaning process. By applying the pH and potential difference relationship, the cleaning solution selectively removes residues without extracting or damaging the copper underlying structure
Solution Approach 2:
The patent introduces a specially formulated cleaning solution as an intermediary substance between the etching process and the final product. This intermediary medium carries out the residue removal function while being controlled to not cause corrosion, mediating between the high-productivity dry etching process and the requirement for residue-free surfaces
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
Effectively removes post-etch residues without damaging the copper lines, reducing the risk of corrosion and maintaining the electrical integrity of semiconductor devices.
Implementation Method 1
the dielectric layer and the copper line are cleaned by a solution with a PH value
Implementation Method 2
a potential difference is formed between the first region of the copper line and the second region of the copper line
Data Source
AI summary
A method of cleaning post-etch residues on a copper line includes providing a copper line which is divided into a first region and a second region. A dielectric layer is formed on the copper line. After that, the dielectric layer is etched to form openings in the dielectric layer. A number of openings within the first region is more than a number of openings in the second region. During the etching process, a potential difference is formed between the first region and the second region of the copper line. Finally, the dielectric layer and the copper line are cleaned by a solution with a PH value. The PH value has a special relation with the potential difference.