Post-CMP Cleaning Composition for Metallic Residue Removal
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Solution Overview
Problem
Existing post-CMP cleaning technologies struggle to effectively remove metallic residues such as Fe, W, Ti, and TiN from semiconductor wafers, leading to defects and degradation of electrical performance in advanced semiconductor devices.
Innovation Solution
A cleaning composition comprising organic acids, fluoride compounds, polymeric additives, and optional surfactants, corrosion inhibitors, and defoaming agents, which are used to remove residues and improve cleaning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cleaning compositions are used for post-CMP cleaning, then the cleaning process is simple, but metallic residues (Fe, W, Ti, TiN) remain on the wafer surface causing defects and electrical performance degradation
Solution Approach 1:
The patent modifies the chemical composition parameters of the cleaning solution by incorporating specific organic acids (oxalic acid, citric acid, malonic acid) and fluoride compounds in optimized concentrations. This chemical parameter change enables effective removal of metallic residues while controlling etch rates on dielectric films, thereby improving electrical performance without excessive material removal
Solution Approach 2:
The patent uses a composite cleaning formulation combining multiple active ingredients (organic acids, fluoride compounds, polymers, surfactants) rather than a single chemical agent. This composite approach synergistically addresses multiple contamination types (metallic residues, organic residues, inorganic particles) simultaneously, improving reliability while removing harmful metallic contaminants
2Object-generated harmful factors
If stronger cleaning chemistry is used to remove metallic residues, then residue removal improves, but etching of dielectric films increases causing surface damage
Solution Approach 1:
The patent carefully balances the concentration parameters of aggressive cleaning agents (organic acids and fluoride compounds) to achieve selective removal of metallic residues while maintaining controlled etch rates on dielectric films. The optimized formulation parameters enable differential reactivity that favors residue removal over film damage
Solution Approach 2:
The patent introduces polymers and surfactants as intermediary substances that modify the interaction between the cleaning chemistry and the wafer surface. These intermediaries help solubilize and remove metallic residues through complexation and surface activity while the organic acid component provides controlled etching, thereby mediating between aggressive residue removal and film protection
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 effectively removes metallic residues, reduces corrosion, and enhances the electrical performance of semiconductor devices by minimizing surface defects and etching dielectric films at controlled rates.
Implementation Method 1
The formulations or compositions (formulation and composition are exchangeable) in the present invention were found to be very effective in removing the residues left behind by the above described CMP polishing process
Implementation Method 2
The cleaning composition comprising organic acids, fluoride compounds, polymeric additives
Implementation Method 3
optional a surfactant, corrosion inhibitors, defoaming agent, biological preservatives, pH adjusting agents
Implementation Method 4
etching dielectric films at controlled rates
Data Source
AI summary
Provided are formulations that offer a high cleaning effect on inorganic particles, organic residues, chemical residues, reaction products on the surface due to interaction of the wafer surface with the Chemical Mechanical Planarization (CMP) slurry and elevated levels of undesirable metals on the surface left on the semiconductor devices after the CMP. The post-CMP cleaning formulations comprise one or more organic acid, one or more polymer and a fluoride compound with pH <7 and optionally a surfactant with two sulfonic acid groups.