CMP Slurry with Polymer-Coated Ceria for Selective Oxide Polishing
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Solution Overview
Problem
Current CMP slurries struggle to maintain a high polishing speed for oxide layers on nitride layers while controlling the selectivity ratio and minimizing surface defects during the shallow trench isolation process in semiconductor manufacturing.
Innovation Solution
A CMP slurry composition comprising metal oxide particles, a diisocyanate compound, and an amphoteric ion compound, specifically designed to achieve a polishing speed of 2000 Å/minute or more with a selectivity ratio of 50 or more, and surface defects below 70 nm, using ceria or other metal oxide particles with positive zeta potential and a diisocyanate compound with a hydrophilic group.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ceria abrasives are used at low concentration to achieve high polishing speed, then productivity is improved, but control over selectivity ratio and surface defects becomes difficult
Solution Approach 1:
The patent changes the chemical parameters of the slurry by introducing a diisocyanate compound that reacts with ceria particles to form a polymer coating. This coating modifies the surface properties of the abrasives, enabling high polishing speed at low ceria concentration while maintaining precise control over selectivity ratio and reducing surface defects through controlled chemical interaction between the polymer and oxide layers
Solution Approach 2:
The patent creates a composite structure by forming a polymer coating on ceria particles through reaction with diisocyanate compound. This composite abrasive combines the high reactivity of ceria with the controlled release properties of the polymer matrix, achieving both high productivity and precise manufacturing control
2Productivity
If ceria abrasives are used at low concentration to achieve high polishing speed, then productivity is improved, but surface defects increase
Solution Approach 1:
The patent modifies the operational parameters by controlling the polymer coating thickness and composition on ceria particles. This controlled modification allows the abrasives to maintain high polishing speed while the polymer matrix regulates the interaction with the oxide layer, preventing excessive material removal and reducing surface defects below 70 nm
3Productivity
If oxide layer is rapidly removed in primary polishing to improve productivity, then polishing speed is improved, but control over remaining oxide thickness and surface quality deteriorates
Solution Approach 1:
The patent introduces dynamic control into the polishing process through the polymer-coated abrasives. The polymer matrix provides a controlled release mechanism that adjusts the abrasiveness during polishing, enabling rapid initial material removal followed by automatic reduction in aggressiveness to achieve surface planarity and remove remaining oxide without creating defects
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 effectively maintains high polishing efficiency for oxide layers on nitride layers with controlled selectivity and minimized surface defects, enhancing the precision and yield of semiconductor device fabrication.
Implementation Method 1
CMP slurries comprising ceria particles have attracted attention as a major material for controlling selectivity of a polishing speed
Implementation Method 2
Ceria abrasives have strong reactivity with an oxide layer and thus, at a low concentration of about 1% or less, the ceria abrasives may exert a polishing speed that is about two times faster than silica abrasives
Implementation Method 3
A CMP slurry composition comprising metal oxide particles, a diisocyanate compound, and an amphoteric ion compound, specifically designed to achieve a polishing speed of 2000 Å/minute or more with a selectivity ratio of 50 or more, and surface defects below 70 nm
Implementation Method 4
The CMP slurry composition includes metal oxide particles, a diisocyanate compound, and deionized water
Data Source
AI summary
A CMP slurry composition includes metal oxide particles, a diisocyanate compound, and deionized water. The CMP slurry composition is capable of selectively controlling polishing speed of a wafer surface having a convex portion and a concave portion, such that primary polishing and secondary polishing can be performed rapidly while stopping polishing of the nitride layer upon the secondary polishing.