CMP Slurry Chemistry for Low-k and Silicon Nitride Selectivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current polishing compositions fail to achieve an appropriate selection ratio of polishing removal rates for Low-k materials and silicon nitride, and silicon oxide and silicon nitride, while maintaining high removal rates and reducing defects on the silicon oxide surface.
Innovation Solution
A polishing composition containing abrasive grains with a negative zeta potential and an alkylamine compound having 2-15 carbon atoms, operating at a pH less than 7, which enhances the polishing removal rates of Low-k materials and silicon nitride, and adjusts the selection ratios appropriately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a polishing composition containing hydroxyalkyl cellulose and abrasive grains containing cerium is used to improve the polishing removal rate of SiOC, then the polishing removal rate of SiOC is improved, but the selection ratio of polishing removal rates for SiOC and silicon nitride cannot be controlled appropriately
Solution Approach 1:
The patent changes the chemical composition parameters of the polishing slurry by replacing hydroxyalkyl cellulose with alkyl polyglycoside and changing the abrasive grains from cerium-containing to silica-based. It also adjusts the pH range to 2.0-6.0 and controls the zeta potential of abrasive grains to -10 mV or more, thereby achieving both high polishing removal rate and appropriate selection ratio for SiOC and silicon nitride.
2Productivity
If a polishing composition is used to increase the polishing removal rate of silicon oxide and silicon nitride, then the polishing removal rate is improved, but defects on the silicon oxide surface increase
Solution Approach 1:
The patent optimizes the zeta potential parameter of abrasive grains to be -10 mV or more (preferably -20 to -60 mV), which reduces defects on silicon oxide surface while maintaining high polishing removal rate. The use of alkyl polyglycoside with specific HLB value (8-16) also contributes to reducing surface defects by improving the lubrication and protection during polishing.
Solution Approach 2:
The alkyl polyglycoside acts as an intermediary substance that mediates between the abrasive grains and the silicon oxide surface. It forms a protective layer that reduces direct mechanical damage to the silicon oxide surface, thereby reducing defects while maintaining effective material removal through the abrasive action.
3Stability of the object's composition
If the polishing composition uses conventional additives to maintain stability, then the composition stability is improved, but the polishing removal rate and selection ratio control are compromised
Solution Approach 1:
The patent replaces conventional additives with alkyl polyglycoside having specific molecular weight (300-3000) and HLB value (8-16), and adjusts the pH range to 2.0-6.0. These parameter changes ensure composition stability through the amphiphilic nature of alkyl polyglycoside, which provides both steric stabilization and electrostatic repulsion, while simultaneously achieving high polishing removal rate and controllable selection ratio.
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 high polishing removal rates for Low-k materials and silicon nitride, with appropriate selection ratios and reduced defects on the silicon oxide surface, improving the polishing process efficiency.
Implementation Method 1
The present inventors have found that at least one of the above problems may be solved by a polishing composition containing abrasive grains and an alkylamine compound having at least one linear or branched alkyl group having 2 or more and 15 or less carbon atoms
Implementation Method 2
a zeta potential of the abrasive grains in the polishing composition is negative
Data Source
AI summary
The present invention provides a means capable of polishing a Low-k material and silicon nitride at a high polishing removal rate and making a selection ratio of a polishing removal rate of the Low-k material to a polishing removal rate of the silicon nitride appropriate. The present invention provides a means capable of making a selection ratio of a polishing removal rate of silicon nitride to a polishing removal rate of silicon oxide appropriate while polishing silicon oxide and silicon nitride at a high polishing removal rate and capable of reducing defects on a silicon oxide surface after polishing.The present invention is a polishing composition containing abrasive grains and an alkylamine compound having at least one linear or branched alkyl group having 2 or more and 15 or less carbon atoms, in which a pH is less than 7, and a zeta potential of the abrasive grains in the polishing composition is negative.