Post-CMP Cleaning Composition to Inhibit Molybdenum Etching
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Solution Overview
Problem
Existing post-CMP removal compositions unintentionally remove unacceptable levels of molybdenum from microelectronic device surfaces, leading to faults and pattern defects, especially at higher pH levels, while effectively removing post-CMP residues is crucial for subsequent device processing.
Innovation Solution
Aqueous removal compositions with a pH greater than 10, containing organic additives, cleaning additives, water-miscible solvents, pH adjustors, and specific molybdenum etching inhibitors such as quaternary ammonium compounds, pyridinium compounds, and radical scavengers, which reduce molybdenum etching without compromising residue removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high pH removal composition is used, then post-CMP residue removal effectiveness is improved, but molybdenum etching increases
Solution Approach 1:
The patent introduces molybdenum etching inhibitors as intermediary substances that mediate between the high pH removal composition and the molybdenum material. These inhibitors (such as benzotriazole, phenylmercaptoacetate, and other chelating agents) form protective complexes with molybdenum ions, preventing excessive etching while allowing the high pH composition to effectively remove post-CMP residues. This intermediary mechanism enables the system to achieve both effective cleaning and material protection simultaneously.
Solution Approach 2:
The patent modifies the chemical parameters of the removal composition by adding specific inhibitors that change the etching characteristics. By introducing substances like benzotriazole (0.01-5 wt%), phenylmercaptoacetate (0.01-5 wt%), and other chelating agents, the composition's interaction with molybdenum is fundamentally altered. These parameter changes allow the system to maintain high pH for effective residue removal while controlling the etching rate through chemical complexation.
2Ease of operation
If high pH removal composition is used, then cleaning capability is improved, but device reliability deteriorates due to molybdenum removal
Solution Approach 1:
The molybdenum etching inhibitors serve as protective intermediaries that prevent harmful interactions between the high pH composition and the molybdenum material. By forming stable complexes with molybdenum, these inhibitors (such as benzotriazole, phenylmercaptoacetate, and other chelating agents) protect the material from excessive removal, thereby maintaining device reliability while allowing the high pH composition to provide effective cleaning capability.
Solution Approach 2:
The patent converts the potentially harmful effect of high pH-induced molybdenum etching into a beneficial process by using controlled amounts of etching inhibitors. The inhibitors modify the etching behavior to be more selective and uniform, transforming what would be a harmful material removal process into a controlled cleaning process that maintains reliability. The high pH composition's strong cleaning capability is preserved while the harmful uncontrolled etching is converted into a beneficial controlled process through inhibitor-mediated selective removal.
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 compositions effectively remove post-CMP residues while significantly inhibiting molybdenum etching, maintaining device integrity and preventing defects, even at high pH levels.
Implementation Method 1
at least one molybdenum etching inhibitor selected from the group consisting of: a) a quaternary ammonium compound of Formula A... b) a quaternary ammonium compound of Formula B... c) a pyridinium compound of Formula C or a bipyridinium compound of Formula D... d) a radical scavenger
Implementation Method 2
The removal composition removes less molybdenum from a surface of a microelectronic device comprising molybdenum than the aqueous base composition
Implementation Method 3
The removal composition comprises an aqueous base composition having a pH of greater than 10 comprising water and at least one of an organic additive, a cleaning additive, a water-miscible organic solvent, and a pH adjustor
Implementation Method 4
Chemical Mechanical Polishing or Planarization (CMP) is a process in which material is physically and chemically removed from a surface of a microelectronic device wafer
Data Source
AI summary
The present disclosure relates to removal compositions for at least partially removing post-chemical mechanical polishing (post-CMP) residues from the surface of a microelectronic device. The removal compositions comprise an aqueous base composition and various molybdenum etching inhibitors that reduce the amount of molybdenum removed from the surface of the microelectronic device compared to the aqueous base composition.