Two-Stage CMP Slurry for Ruthenium Removal and Dielectric Selectivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing CMP slurry compositions are ineffective in efficiently polishing new metal materials like ruthenium (Ru) due to its high hardness and limited oxidation capabilities, leading to low removal rates and surface roughness issues.
Innovation Solution
Development of amine-based CMP slurry compositions with specific abrasive, oxidizing, and alkaline components, tailored for two-stage polishing processes to maximize Ru removal while minimizing dielectric material removal, using titanium dioxide (TiO2) abrasives and adjusting pH and ionic strength to form soluble Ru byproducts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing CMP slurry compositions are used, then conventional materials can be polished, but new metal materials like ruthenium exhibit low removal rates and surface roughness
Solution Approach 1:
The patent changes the chemical parameters of the slurry by incorporating amine-based alkaline components and adjusting pH levels to create a more aggressive chemical environment that can effectively oxidize and remove hard metal materials like ruthenium, thereby improving removal rate without compromising surface quality
Solution Approach 2:
The patent uses composite slurry formulations combining multiple abrasive particles with different hardness and morphology characteristics, along with oxidizing agents and amine-based alkaline components, to achieve both high removal rates and smooth surface finish on challenging metal materials
2Productivity
If aggressive polishing is applied to increase Ru removal rate, then productivity improves, but dielectric material removal increases
Solution Approach 1:
The patent employs abrasive particles with locally optimized properties - using a combination of hard particles for metal removal and softer particles that preferentially interact with dielectric materials - allowing selective removal rates where Ru is removed aggressively while dielectric removal is controlled
Solution Approach 2:
The patent adjusts chemical parameters including pH, ionic strength, and oxidizing agent concentration to enhance the selectivity of the polishing process, creating conditions where Ru oxidation and removal are accelerated while dielectric material remains relatively protected
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
Achieves high Ru removal rates with minimal dielectric material removal, reducing surface roughness and ensuring planarity for semiconductor fabrication, enhancing device performance and reliability.
Implementation Method 1
the oxidizing component oxidizes the metal material into soluble byproducts
Implementation Method 2
a slurry composition for chemical mechanical planarization comprising an abrasive component, an oxidizing component, and an amine-based alkaline component
Implementation Method 3
adjusting pH and ionic strength to form soluble Ru byproducts
Data Source
AI summary
The method includes receiving a semiconductor structure including a first surface, the first surface including a uniform material composition of ruthenium (Ru), selecting a first polishing slurry including a first abrasive component of titanium oxide and a first amine-based alkaline component of ammonium hydroxide, selecting a second polishing slurry including a second abrasive component of silicon oxide, a second amine-based alkaline component of hydroxyamine, and a non-amine alkaline component, polishing the first surface with the first polishing slurry until a second surface is exposed, the second surface including a conductive material and a dielectric material, and polishing the second surface with the second polishing slurry.