Post-CMP Cleaning Composition for Residue Removal and Low Corrosion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing post-CMP cleaning technologies struggle to effectively remove inorganic particles, organic residues, chemical residues, and elevated levels of undesirable metals from semiconductor wafers, leading to defective chips due to insufficient cleaning efficiency, especially with the advancement of smaller defect size and number thresholds.
Innovation Solution
A post-CMP cleaning composition comprising organic acids, surfactants with sulfonic acid groups, fluoride compounds, water-soluble polymers, corrosion inhibitors, and pH adjusting agents, which can be diluted with DI water, effectively removes metallic and organic residues while etching dielectric films at controlled rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional brush scrubbing process is used for post-CMP cleaning, then mechanical removal of particles is achieved, but inorganic particles, organic residues, chemical residues, and metal contaminants remain on the wafer surface
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the cleaning solution, specifically incorporating organic acids (oxalic acid, citric acid, malonic acid) with controlled concentrations (0.1-10 wt%, preferably 0.5-5 wt%) and surfactants (0.01-5 wt%, preferably 0.1-1 wt%). This chemical parameter modification enables effective removal of inorganic particles, organic residues, chemical residues, and metal contaminants that conventional mechanical brush scrubbing cannot eliminate.
Solution Approach 2:
The patent employs composite materials by creating a multi-component cleaning solution system that combines organic acids, surfactants (including diphenyl disulfonic acid surfactants and other anionic/non-ionic surfactants), water-soluble polymers, and corrosion inhibitors. This composite chemical system works synergistically to address multiple types of contaminants simultaneously, achieving comprehensive cleaning effectiveness beyond what single-component systems can provide.
2Reliability
If cleaning chemistry is dispensed to remove residues, then residue removal efficiency improves, but surface roughness and corrosion increase
Solution Approach 1:
The patent controls the harmful effects through precise parameter changes, specifically maintaining pH within 2-6 (preferably 3-5) and controlling organic acid concentrations at 0.1-10 wt%. These parameter controls ensure effective residue removal while minimizing excessive etching and surface roughening. The balanced chemical composition prevents aggressive corrosion that would occur with stronger acids alone.
Solution Approach 2:
The patent introduces corrosion inhibitors as intermediary substances that mediate between the cleaning chemistry and the wafer surface. These inhibitors form protective layers or complex with metal ions, preventing direct aggressive attack on the semiconductor structures while allowing the organic acids and surfactants to continue removing residues. This intermediary mechanism enables effective cleaning without proportional increases in surface damage.
3Productivity
If stronger cleaning chemistry is used to remove elevated levels of metals and organic residues, then cleaning efficiency improves, but etching of dielectric films increases
Solution Approach 1:
The patent optimizes the concentration parameters of cleaning agents to achieve high cleaning efficiency with minimal dielectric etching. Organic acids are maintained at 0.1-10 wt% (preferably 0.5-5 wt%) and surfactants at 0.01-5 wt% (preferably 0.1-1 wt%), creating a balanced chemical environment that prioritizes contaminant removal over aggressive etching. This parameter optimization ensures cleaning productivity without excessive material loss.
Solution Approach 2:
The patent applies local quality principles by creating a cleaning chemistry that selectively targets different contaminants with different mechanisms. The surfactants specifically bind to organic residues and metal particles, while the organic acids dissolve inorganic contaminants, allowing the cleaning action to be concentrated on contaminants rather than uniformly etching the dielectric film. This selective action improves cleaning efficiency while minimizing bulk material 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 composition significantly improves residue removal, reduces surface roughness, and minimizes corrosion, achieving low turbidity and precise etching rates, enhancing semiconductor device performance and yield.
Implementation Method 1
The compositions can be diluted with DI water 2 to 500 times at the point of use... effectively removes metallic and organic residues
Implementation Method 2
at least two surfactants; wherein at least one of the at least two surfactants is a first type surfactant having at least two sulfonic acid groups
Implementation Method 3
etching dielectric films at controlled rates... achieving low turbidity and precise etching rates
Implementation Method 4
optionally fluoride compound... significantly improves residue removal, reduces surface roughness, and minimizes corrosion
Data Source
AI summary
The present invention provides a cleaning composition comprises water; one or more organic acid; at least two surfactants wherein the first type surfactant is a diphenyl disulfonic surfactant, the second type surfactant has a surface tension of less than 50 dynes/cm at 0.01 wt % concentration in water, and the second type surfactant is not the first type surfactant; and optionally fluoride compounds, polymers, corrosion inhibitors, biological preservatives, pH adjusting agents.