CMP Slurry Chelator and Oxidizer Balance for Copper Dishing
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Solution Overview
Problem
Current copper chemical mechanical planarization (CMP) technologies face challenges in achieving high removal rates and low dishing for advanced technology nodes, failing to meet the requirements of high selectivity and low defectivity, especially for copper and other metal films like Co, W, and Ni.
Innovation Solution
Development of CMP polishing compositions comprising abrasives, chelators, corrosion inhibitors, oxidizing agents, and chemical additives, such as morpholino compounds, which include a combination of single, dual, or tris chelators, and organic quaternary ammonium salts, to enhance copper removal rates and reduce dishing, while maintaining selectivity and corrosion protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP formulations are used, then copper removal is achieved, but dishing increases and removal rates become insufficient for advanced technology nodes
Solution Approach 1:
The patent modifies the chemical composition parameters of the CMP slurry by incorporating specific chelating agents (EDTA, DTPA, HEDPA), corrosion inhibitors (benzotriazole, tolyltriazole), and oxidizing agents (hydrogen peroxide, ammonium persulfate) in optimized concentrations to achieve both high removal rates and low dishing
Solution Approach 2:
The formulation combines multiple functional components including abrasives (colloidal silica, alumina), chelating agents, corrosion inhibitors, oxidizing agents, and pH buffers in a synergistic composite slurry system that simultaneously achieves high copper removal and minimal dishing
2Productivity
If higher removal rates are achieved, then productivity increases, but selectivity between copper and barrier materials decreases
Solution Approach 1:
The patent optimizes pH parameters (maintained between 7-11 using phosphate or borate buffers) and chemical concentration parameters to enhance copper removal kinetics while preserving barrier material integrity, achieving both high productivity and selectivity
3Productivity
If copper removal is enhanced, then productivity improves, but corrosion protection decreases
Solution Approach 1:
The patent introduces corrosion inhibitor molecules (benzotriazole, tolyltriazole) that act as intermediaries between the copper surface and the aggressive CMP environment, forming protective films that prevent corrosion while allowing controlled removal
Solution Approach 2:
The formulation adjusts chemical parameters including adding hydrogen peroxide and ammonium persulfate as oxidizing agents to control copper surface chemistry, while maintaining corrosion inhibitor concentrations to balance removal rate and corrosion 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 CMP compositions provide high and tunable copper removal rates, low dishing, and high selectivity between copper and other barrier or dielectric films, along with improved corrosion protection and extended polish pad life, effectively addressing the limitations of existing CMP technologies.
Implementation Method 1
at least one chelator; such as single, dual or tris chelators
Implementation Method 2
oxidizing agent
Implementation Method 3
abrasive
Data Source
AI summary
Provided are Chemical Mechanical Planarization (CMP) formulations 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 formulations comprise water; abrasive; single chelator, dual chelators or tris chelators; morpholino family compounds as Cu dishing reducing agents. Additionally, organic quaternary ammonium salt, corrosion inhibitor, oxidizer, pH adjustor and biocide can be used in the formulations.