Dual-Amine CMP Slurry for Molybdenum Removal and Low Defectivity
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Solution Overview
Problem
Molybdenum, due to its hardness and chemical resistance, is difficult to polish with high removal rates and low defectivity in the CMP process, posing a challenge for semiconductor substrate processing.
Innovation Solution
A polishing composition comprising at least one abrasive, an organic acid or its salt, a first amine compound with a 6-24 carbon alkyl chain, a second amine compound with two nitrogen atoms, and an aqueous solvent, which selectively removes molybdenum and its alloys while maintaining excellent corrosion resistance and low static etch rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP slurry is used on molybdenum, then the polishing process can proceed, but the removal rate is low and defectivity is high due to molybdenum's hardness and chemical resistance
Solution Approach 1:
The patent modifies the chemical composition parameters of the CMP slurry by incorporating specific organic acids (e.g., acetic acid, formic acid), amines (e.g., ethylenediamine, diethylenetriamine), and chelating agents (e.g., EDTA, DTPA) to alter the chemical reactivity toward molybdenum, thereby achieving both high removal rate and low defectivity
Solution Approach 2:
The patent creates a composite chemical formulation combining multiple components (abrasives, organic acids, amines, chelating agents, surfactants) that work synergistically to overcome molybdenum's inherent resistance to polishing, enabling effective material removal while maintaining surface quality
2Productivity
If aggressive polishing is applied to increase removal rate, then productivity improves, but corrosion resistance and static etch rate increase
Solution Approach 1:
The patent introduces chelating agents (EDTA, DTPA, HEDP) and organic acids as intermediary substances that selectively complex with molybdenum ions during polishing, facilitating controlled removal while preventing unwanted corrosion and etching of the molybdenum layer
Solution Approach 2:
The patent carefully controls the pH range (2-7) and chemical concentrations to optimize the balance between removal rate and corrosion resistance, using buffered formulations that maintain stable chemical conditions during the polishing process
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 a controlled and efficient removal of molybdenum and its alloys with a high removal rate and low corrosion, reducing defects and improving the CMP process for semiconductor substrates.
Implementation Method 1
CMP is a process used to planarize/flatten a wafer surface by removing material using abrasion-based physical processes
Implementation Method 2
CMP is a process used to planarize/flatten a wafer surface by removing material using abrasion-based physical processes concurrently with surface-based chemical reactions
Data Source
AI summary
This disclosure relates polishing compositions that include (1) at least one abrasive; (2) at least one organic acid or a salt thereof; (3) at least one first amine compound, the at least one first amine compound including an alkylamine having a 6-24 carbon alkyl chain; (4) at least one second amine compound containing at least two nitrogen atoms, the second amine compound being different from the first amine compound; and (5) an aqueous solvent.