Tunable Selectivity Slurries for CMP Metal-Dielectric Planarity
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Solution Overview
Problem
Conventional chemical-mechanical polishing compositions lack tunable selectivity, leading to inconsistent removal rates of metal and dielectric layers during polishing, resulting in undesirable erosion and topography issues in integrated circuit manufacturing.
Innovation Solution
A method of preparing a chemical-mechanical polishing composition by mixing two compositions with different selectivities for metal and dielectric layers, allowing for adjustable ratios to achieve a final desired selectivity, ensuring equal removal rates for both layers during a single polishing step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a polishing composition with high selectivity is used, then the removal rate of the selected material is significantly higher, but other materials are removed at much lower rates causing non-uniform polishing and erosion
Solution Approach 1:
The patent applies parameter changes by adjusting the pH of the polishing composition to achieve non-selective polishing. Specifically, the composition maintains a pH of less than 9.5 (preferably less than 9.0, more preferably less than 8.5), which enables substantially equal removal rates for both metal and dielectric layers, resolving the contradiction between high removal rate and uniform polishing across different materials
Solution Approach 2:
The patent uses a composite polishing composition containing multiple abrasive particles with different characteristics. The composition includes abrasive particles with an average粒径 of 0.01 to 1.0 micrometers, comprising at least two different types of abrasives, which work synergistically to achieve non-selective removal of both metal and dielectric materials at substantially equal rates
2Manufacturing precision
If a polishing composition with low selectivity is used, then each material is removed at substantially the same rate improving topography, but the removal rate of the selected material is reduced
Solution Approach 1:
The patent optimizes the pH parameter to achieve non-selective polishing while maintaining high removal rates. By controlling pH to be less than 9.5, the composition achieves substantially equal removal rates for metal and dielectric layers, simultaneously improving surface uniformity and maintaining productivity
Solution Approach 2:
The composite abrasive system with particles of 0.01 to 1.0 micrometers provides both non-selective removal capability and high removal rate. The multi-component abrasive mixture enables simultaneous optimization of surface topography uniformity and polishing productivity
3Ease of manufacture
If a fixed-selectivity polishing composition is used, then the composition is optimized for specific substrates, but it does not exhibit identical selectivity across different device manufacturers leading to erosion
Solution Approach 1:
The patent establishes a standardized pH parameter range (less than 9.5, preferably less than 9.0, more preferably less than 8.5) that ensures non-selective polishing performance across different device manufacturers and processing conditions. This standardized parameter control makes the composition universally reliable for polishing both metal and dielectric layers with substantially equal removal rates
Solution Approach 2:
The polishing composition is designed to be universally applicable across different device manufacturers and substrate types. The composition achieves substantially equal removal rates for both metal and dielectric layers under various processing conditions, making it a multi-functional solution that eliminates erosion problems regardless of the specific user or application
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
Enables precise control over the selectivity of the polishing process, optimizing the removal rates of metal and dielectric layers, thereby reducing erosion and improving surface planarity, and allowing end-users to tailor the composition for specific substrates and apparatus.
Implementation Method 1
The polishing of the substrate by the relative movement of the pad and the substrate typically is further aided by the chemical activity of the polishing composition
Implementation Method 2
The relative movement of the pad and substrate serves to abrade the surface of the substrate to remove a portion of the material from the substrate surface
Data Source
AI summary
The invention provides a method of preparing a chemical-mechanical polishing composition for polishing a substrate with at least a first layer and a second layer. The method comprises providing both a first chemical-mechanical polishing composition comprising an abrasive with a selectivity for a first layer as compared to a second layer and a second chemical-mechanical polishing composition comprising an abrasive with different selectivity for the first layer as compared to the second layer, wherein the second chemical-mechanical polishing composition is stable in the presence of the first chemical-mechanical polishing composition, and mixing the first and second chemical-mechanical polishing compositions in a ratio to achieve a final selectivity for the first layer as compared to the second layer. The invention further provides a method of chemically-mechanically polishing a substrate.