CMP Polishing Liquid Composition for Fast Oxide Removal With Fewer Scratches
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Solution Overview
Problem
Cerium-based polishing liquids struggle to achieve high polishing rates for silicon oxide, particularly on pattern wafers with fine concavo-convex patterns, and tend to result in polishing scratches.
Innovation Solution
A polishing liquid containing cerium-based particles, a 4-pyrone-based compound, and a nitrogen-containing hydroxyalkyl compound, such as ethylenedinitrilotetraethanol, which promotes a high polishing rate for silicon oxide convex portions while minimizing scratches by enhancing interaction with the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a silica-based polishing liquid is used to achieve high polishing rate for silicon oxide, then polishing rate is improved, but polishing scratches increase causing defects
Solution Approach 1:
The patent changes the chemical composition parameters of the polishing liquid by using cerium-based particles instead of silica-based particles, and by controlling pH to 8.0 or less with specific additives, thereby reducing polishing scratches while maintaining polishing rate
Solution Approach 2:
The patent creates a composite polishing liquid system combining cerium-based particles with specific organic additives (4-pyrone-based compound and nitrogen-containing compound with hydroxyalkyl group) to achieve both high polishing rate and reduced scratches
2Object-affected harmful factors
If a cerium-based polishing liquid is used to reduce polishing scratches, then polishing scratches are reduced, but polishing rate for silicon oxide of convex portions decreases
Solution Approach 1:
The patent optimizes pH parameter to 8.0 or less and controls the concentration ratio of cerium-based particles to additives, which enhances the chemical reaction efficiency between cerium particles and silicon oxide convex portions, thereby restoring high polishing rate
Solution Approach 2:
The patent introduces organic additives (4-pyrone-based compound and nitrogen-containing compound with hydroxyalkyl group) as intermediaries that facilitate the chemical reaction between cerium-based particles and silicon oxide, enhancing polishing rate while maintaining scratch reduction
3Manufacturing precision
If polishing is performed on pattern wafers with fine concavo-convex patterns, then device integration is improved, but polishing rate uniformity across convex and concave portions becomes difficult to control
Solution Approach 1:
The patent creates local quality differences in the polishing liquid's chemical environment by controlling pH and additive concentrations, which enables selective enhancement of polishing rate at convex portions while maintaining appropriate polishing at concave portions
Solution Approach 2:
The patent adjusts chemical parameters (pH ≤ 8.0, specific additive concentrations) to optimize the chemical-mechanical polishing reaction, achieving uniform polishing rate across patterned surfaces with fine concavo-convex structures
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 polishing liquid achieves a high polishing rate for silicon oxide convex portions with reduced scratches, suitable for pattern wafers with complex patterns, and maintains high-speed polishing without significant surface irregularity dependence.
Implementation Method 1
a polishing liquid for CMP, containing: abrasive grains; an additive; and water, in which the abrasive grains include cerium-based particles
Implementation Method 2
the additive includes (A1) a 4-pyrone-based compound represented by General Formula (1) below and (B) a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded
Data Source
AI summary
A polishing liquid for CMP, containing: abrasive grains; an additive; and water, in which the abrasive grains include cerium-based particles, the additive includes (A1) a 4-pyrone-based compound represented by General Formula (1) below and (B) a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded. A polishing liquid for CMP, containing: abrasive grains; an additive; and water, in which the abrasive grains include cerium-based particles, the additive includes (A2) picolinic acid and (B) a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded.[in the formula, X11, X12, and X13 are each independently a hydrogen atom or a monovalent substituent.]