Post-CMP Cleaning Composition for Metallic Residue Removal
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Solution Overview
Problem
Current post-CMP cleaning technologies face challenges in effectively removing metallic residues such as iron, tungsten, and titanium compounds from semiconductor wafers, which can lead to electrical performance degradation due to the presence of these residues after the chemical mechanical planarization process.
Innovation Solution
A cleaning composition comprising non-ionic polymers with ethylene oxide groups, organic acids or their salts, fluoride compounds, and a surfactant, specifically designed to be diluted with deionized water, which effectively removes metallic and organic residues while minimizing corrosion and surface roughness, and is suitable for various cleaning techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional brush scrubbing cleaning process is used after CMP, then cleaning can be performed, but metallic residues such as iron, tungsten, and titanium compounds remain on the wafer surface causing electrical performance degradation
Solution Approach 1:
The cleaning composition uses specific chemical parameters including fluoride compounds (0.1-10 wt%) to dissolve metallic residues, organic acids (0.1-10 wt%) to remove organic contaminants, and chelating agents (0.01-5 wt%) to bind metal ions. This chemical parameter approach replaces mechanical brush scrubbing and effectively removes iron, tungsten, and titanium compounds while protecting electrical performance.
Solution Approach 2:
The invention employs a composite cleaning formulation combining multiple chemical components: fluoride compounds (for metallic residue removal), organic acids (for organic contaminant dissolution), chelating agents (for metal ion binding), and surfactants (for surface activity). This composite chemistry synergistically addresses multiple types of residues simultaneously, achieving superior cleaning performance compared to single-mechanism approaches.
2Reliability
If strong cleaning chemistry is used to remove residues, then cleaning performance improves, but corrosion and surface damage increase
Solution Approach 1:
The cleaning composition uses intermediaries to facilitate residue removal while protecting the substrate. Chelating agents act as intermediaries that bind metal ions in solution, preventing direct corrosive interaction between aggressive cleaning chemicals and the wafer surface. The formulation includes corrosion inhibitors and buffers that mediate the chemical environment, enabling effective cleaning while maintaining surface integrity and minimizing damage.
Solution Approach 2:
The invention carefully controls chemical parameters including pH (maintained in buffered range), concentration of aggressive agents (fluoride 0.1-10 wt%, organic acid 0.1-10 wt%), and temperature. These parameter optimizations ensure sufficient cleaning power to remove residues while preventing excessive corrosion. The balanced formulation achieves the optimal window between cleaning effectiveness and surface protection.
3Ease of manufacture
If conventional cleaning compositions are used, then simple formulation is maintained, but inability to remove advanced metallic residues poses problem
Solution Approach 1:
The cleaning composition combines multiple specialized chemical components in a unified formulation: fluoride compounds for tungsten and titanium residue removal, organic acids for organic contaminant dissolution, chelating agents for iron and metal ion binding, and surfactants for enhanced surface activity. This composite approach provides comprehensive residue removal capability for advanced semiconductor structures while maintaining a manufacturable single-solution format.
Solution Approach 2:
The cleaning formulation is designed as a universal composition that addresses multiple residue types simultaneously: inorganic metallic residues (iron, tungsten, titanium), organic photoresist residues, and CMP slurry particles. The multi-functional chemistry enables a single cleaning step to handle diverse contaminants that would otherwise require sequential specialized treatments, improving both effectiveness and process efficiency.
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 efficient removal of metallic residues like iron, tungsten, and titanium, improving electrical performance and reducing corrosion, with controlled etch rates for dielectric and metallic films, ensuring high cleaning performance and low defectivity.
Implementation Method 1
non-ionic polymers with ethylene oxide groups
Implementation Method 2
non-ionic polymers with ethylene oxide groups
Implementation Method 3
organic acids or their salts
Implementation Method 4
fluoride compounds
Implementation Method 5
a surfactant
Data Source
Figure 1
AI summary
A post Chemical Mechanical Planarization(CMP) cleaning composition comprising: at least one organic acid or salts thereof selected from the group comprising dicarboxylic acid, hydroxycarboxylic acid, polycarboxylic acid, salts thereof, and combinations thereof; a fluoride compound selected from the group comprising hydrofluoric acid, ammonium fluoride, ammonium bifluoride, quaternary ammonium fluoride and combinations thereof; at least one polymeric additive selected from a group comprising anionic polymer, non-ionic polymer and cationic polymer and combinations thereof; and water; optionally a surfactant selected from the group consisting of non-ionic surfactants, anionic surfactants, cationic surfactants, ampholytic surfactants, and mixtures thereof; corrosion inhibitor; biological preservative; defoaming agent; and pH adjusting agent; wherein the composition has a pH of between 1 to 7. A method of post Chemical Mechanical Planarization (CMP) cleaning a semiconductor wafer comprising at least one surface selected from the group consisting of metallic film, dielectric film, and combinations thereof.