Cerium CMP Slurry Composition for High-Rate Oxide Polishing
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Solution Overview
Problem
The cerium-based polishing liquids used in CMP for silicon oxide polishing struggle to achieve a high polishing rate, particularly on pattern wafers with fine concavo-convex patterns.
Innovation Solution
A polishing liquid for CMP is developed, containing cerium-based particles, a 4-pyrone-based compound, and a compound with a pH of 3.7 or more, which enhances the interaction between the polishing liquid and silicon oxide, thereby increasing the polishing rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a silica-based polishing liquid is used to achieve a high polishing rate for silicon oxide, then the 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 the pH to be 4.0 or higher through specific additives. This parameter change allows achieving a high polishing rate while reducing polishing scratches, resolving the contradiction between productivity and harmful factors.
2Object-affected harmful factors
If a cerium-based polishing liquid is used to reduce polishing scratches, then the harmful factors are reduced, but the polishing rate for silicon oxide of convex portions decreases
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: using cerium-based particles with specific size distribution (0.5-5 μm), controlling pH to be 4.0 or higher with specific additives, and adjusting the concentration of cerium-based particles to 0.1-10 wt%. These coordinated parameter changes enable the cerium-based polishing liquid to achieve both low polishing scratches and high polishing rate for convex portions.
Solution Approach 2:
The patent creates a composite polishing liquid system combining cerium-based particles with specific organic additives (such as carboxylic acids, alcohols, or amines) that work synergistically. The composite formulation enhances the chemical reactivity with silicon oxide while maintaining mechanical polishing properties, resolving the contradiction between reducing scratches and maintaining high polishing rate.
3Productivity
If the pH of the polishing liquid is increased to improve polishing rate, then the polishing rate is improved, but the stability of the polishing liquid composition deteriorates
Solution Approach 1:
The patent introduces specific organic additives (carboxylic acids, alcohols, or amines) as intermediaries that buffer the pH and maintain it at 4.0 or higher without causing precipitation or decomposition. These additives mediate between the high pH requirement for high polishing rate and the stability requirement, forming stable complexes with cerium-based particles and preventing aggregation.
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 of convex portions on pattern wafers with fine concavo-convex patterns, while maintaining low polishing scratches and excellent flatness.
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 (A) a 4-pyrone-based compound represented by General Formula (1) below, and (B1) a compound of which a 1 mM aqueous solution has a pH of 3.7 or more
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, and the additive includes (A) a 4-pyrone-based compound represented by General Formula (1) below, and (B1) a compound of which a 1 mM aqueous solution has a pH of 3.7 or more or (B2) a cyclic compound having at least one functional group selected from the group consisting of a carboxy group, a carboxylate group, an amino group, and a hydroxy group. A polishing liquid for CMP, containing: abrasive grains; an additive; and water, in which the abrasive grains include cerium-based particles, and the additive includes 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.]