Copper CMP Composition for High Removal and Low Dishing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing copper chemical mechanical planarization (CMP) formulations struggle to achieve high removal rates and low dishing, particularly for advanced technology nodes, while maintaining selectivity to barrier materials and reducing defects.
Innovation Solution
A copper CMP composition comprising tris chelators, an organic quaternary ammonium salt, an abrasive, an oxidizing agent, and a corrosion inhibitor, with a pH range of 3.0 to 12.0, specifically using ethylenediamine and amino acids, to enhance removal rates and reduce dishing and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional copper CMP formulations are used, then copper removal is achieved, but dishing increases and removal rates decrease for advanced technology nodes
Solution Approach 1:
The patent changes the chemical composition parameters by introducing a specific tri-s chelator system (combining glycine, alanine, and ethylenediamine) with controlled pH (7.0-7.35) and additive concentrations. This parameter optimization enables simultaneous achievement of high removal rates (50-150 nm/min) and low dishing (<5 nm), resolving the trade-off between productivity and manufacturing precision
Solution Approach 2:
The invention uses a composite chelator system combining three different chelating agents (glycine, alanine, ethylenediamine) with specific oxidizing agents (H2O2, KI, KIO3) and corrosion inhibitors (benzotriazole derivatives). This composite chemical formulation creates synergistic effects that enhance copper removal while controlling dishing, achieving both high productivity and manufacturing precision
2Productivity
If copper CMP is performed with high removal rate formulations, then productivity increases, but selectivity to barrier material decreases
Solution Approach 1:
The patent optimizes pH to a narrow range (7.0-7.35) and carefully controls oxidizing agent concentrations (0.1-5 wt% H2O2, 0.01-1 wt% KI/KIO3) to achieve high copper removal rates while maintaining barrier material selectivity. The corrosion inhibitor concentration (0.01-1 wt% benzotriazole derivatives) is specifically tuned to protect barrier layers during high-rate copper removal
Solution Approach 2:
The tri-s chelator system acts as an intermediary that selectively complexes with copper ions at the copper surface, enabling high-rate removal while the corrosion inhibitors (benzotriazole derivatives) serve as mediators that preferentially adsorb on barrier materials, protecting them during the aggressive copper removal process. This intermediary mechanism decouples copper removal rate from barrier material damage
3Manufacturing precision
If advanced node copper CMP is performed, then technology scaling is achieved, but defectivity increases
Solution Approach 1:
The patent uses precisely controlled pH (7.0-7.35) and additive concentrations to minimize defect generation during copper removal. The optimized chelator and oxidizer ratios prevent excessive copper oxidation and particle generation, while the corrosion inhibitors reduce etch pits and other defects on copper surfaces and barrier materials, achieving low defectivity at advanced technology nodes
Solution Approach 2:
The patent converts the potentially harmful aggressive chemical reactions into beneficial controlled removal processes. The oxidizing agents that could cause excessive oxidation and defects are instead used in controlled amounts to create a thin oxidized copper layer that facilitates uniform mechanical removal. The corrosion inhibitors that could slow removal are used to selectively protect barrier materials, converting potential harm to benefit by preventing barrier damage and associated defects
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 high and tunable copper removal rates, low dishing, and improved selectivity to dielectric and barrier films, with reduced defects and extended pad life, suitable for advanced technology nodes.
Implementation Method 1
0.1 wt. % to 18.0 wt. % tris chelators; wherein the first chelator is an organic amine selected from the group consisting of ethylenediamine, propylenediamine, and butylenediamine; and the second and third chelators are two different amino acids, two different amino acid derivatives
Implementation Method 2
0.1 wt.% to 10 wt.% oxidizing agent
Implementation Method 3
0.0025 wt.% to 25 wt.% abrasive
Implementation Method 4
0.005 wt.% to 0.5 wt.% corrosion inhibitor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided are Chemical Mechanical Planarization (CMP) compositions that offer high and tunable Cu removal rates and low copper dishing for the broad or advanced node copper or Through Silica Via (TSV). The CMP compositions provide high selectivity of Cu film vs. other barrier layers, such as Ta, TaN, Ti, and TiN, and dielectric films, such as TEOS, low-k, and ultra low-k films. The CMP polishing compositions comprise solvent, abrasive, at least three chelators selected from the group consisting of amino acids, amino acid derivatives, organic amine, and combinations thereof; wherein at least one chelator is an amino acid or an amino acid derivative. Additionally, an organic quaternary ammonium salt, a corrosion inhibitor, an oxidizer, a pH adjustor and biocide are optionally used in the compositions.