Copper CMP Composition for High Selectivity and Low Static Etching
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Solution Overview
Problem
Current copper chemical mechanical planarization (CMP) processes fail to meet the requirements for advanced technology nodes, particularly in achieving high and tunable copper removal rates while maintaining low copper static etching rates and high selectivity between copper and other materials.
Innovation Solution
Development of CMP polishing compositions comprising abrasive, oxidizing agents, dual chelators, and Cu static etching rate reducing agents, along with optional corrosion inhibitors and pH adjusting agents, to enhance copper removal rates and reduce static etching, specifically designed for copper and Through Silica Via (TSV) applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional Cu CMP polishing compositions are used, then Cu removal rate can be maintained, but Cu static etching rate increases and selectivity to barrier material decreases
Solution Approach 1:
The invention changes the chemical parameters of the polishing composition by incorporating specific chelators (amino acids like glycine, L-alanine, DL-alanine) and corrosion inhibitors (benzotriazole, 2-aminobenzimidazole) to optimize the balance between Cu removal rate and Cu static etching rate, achieving high removal rate with low etching and high barrier material selectivity
Solution Approach 2:
The invention uses a composite formulation combining multiple components including colloidal silica abrasive, chelators, oxidizing agents, and corrosion inhibitors working synergistically to achieve the dual objective of high Cu removal rate and low Cu static etching rate while maintaining high selectivity to barrier materials
2Productivity
If polishing composition is optimized for high Cu removal rate, then productivity improves, but metal loss increases
Solution Approach 1:
The invention optimizes chemical parameters including pH (5.0-9.0), chelator concentration (0.1-10 wt%), and corrosion inhibitor concentration (0.01-1 wt%) to achieve high Cu removal rate while minimizing metal loss through controlled chemical reactions and reduced static etching
3Manufacturing precision
If polishing composition provides high selectivity to barrier material, then manufacturing precision improves, but Cu removal rate decreases
Solution Approach 1:
The invention adjusts chemical parameters including using specific chelators with appropriate binding affinity to Cu ions, optimizing oxidizing agent concentration (0.1-5 wt% hydrogen peroxide), and controlling pH to achieve the optimal balance between Cu removal rate and selectivity to barrier materials like Ta, TaN, Ti, and TiN
Solution Approach 2:
The chelators act as intermediaries that selectively complex with Cu ions during the polishing process, enabling controlled removal of Cu while leaving barrier materials intact, thus achieving high selectivity without sacrificing removal rate
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 CMP compositions provide high and tunable copper removal rates, low static etching rates, and high selectivity between copper and other barrier or dielectric films, extending polish pad life and enabling stable end-point detection.
Implementation Method 1
oxidizing agent
Implementation Method 2
at least two chelators
Data Source
AI summary
Provided are Chemical Mechanical Planarization (CMP) compositions that offer high and tunable Cu removal rates and low Cu static etching rates for polishing the broad bulk or advanced node copper or Through Silica Via (TSV). The CMP compositions also provide high selectivity of Cu film vs. other barrier layers, such as Ta, TaN, Ti, TiN, and SiN; and dielectric films, such as TEOS, low-k, and ultra-low-k films. The CMP polishing compositions comprise abrasive, oxidizer, at least two chelators selected from the group consisting of amino acids, amino acid derivatives, and combinations therefore; the Cu static etching reducing agents include, but not limited to, organic alkyl sulfonic acids with straight or branched alkyl chains, and salts of organic alkyl sulfonic acids.