Polishing Composition for Low-Defect SiN and SiO2 CMP
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Solution Overview
Problem
Conventional polishing compositions struggle to achieve both low selectivity and low defect performance simultaneously when polishing silicon oxide and silicon nitride films.
Innovation Solution
A polishing composition containing abrasives with a positive zeta potential and a cyclic compound with a ring structure and multiple anionic functional groups, which improves the polishing removal rate of silicon nitride while reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If abrasives with positive zeta potential are used, then defect performance is improved, but polishing removal rate of silicon nitride deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the polishing slurry by introducing a cyclic compound with specific functional groups (carboxyl, hydroxyl, or amino groups) that can interact with the positively charged abrasives and silicon nitride surface. This chemical parameter modification enables simultaneous achievement of low defect density and high polishing removal rate by optimizing the interaction mechanisms.
Solution Approach 2:
The invention uses a composite system combining traditional abrasives (silica, alumina, or diamond particles with positive zeta potential) with an organic cyclic compound (such as cyclic carboxylic acid or its derivative). This composite formulation creates synergistic effects where the abrasives provide mechanical removal and the cyclic compound provides chemical enhancement, achieving both low defects and high removal rate.
2Manufacturing precision
If polishing composition achieves low selectivity, then silicon oxide and silicon nitride are polished at same rate, but defect performance deteriorates
Solution Approach 1:
The invention modifies the chemical parameters of the polishing slurry by incorporating cyclic compounds with specific functional groups that can simultaneously affect the polishing rates of both silicon oxide and silicon nitride. The carboxyl, hydroxyl, or amino groups in the cyclic compound create chemical interactions that balance the removal rates while maintaining low defect density through controlled surface reactions.
3Adaptability or versatility
If conventional polishing composition is used, then one performance is satisfied, but both low selectivity and low defect performance cannot be achieved simultaneously
Solution Approach 1:
The cyclic compound in the invention serves multiple functions simultaneously: it enhances the polishing removal rate of silicon nitride, maintains low selectivity between silicon oxide and silicon nitride, and reduces defect density. This multi-functional additive allows a single polishing composition to achieve all three performance targets that were previously mutually exclusive.
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 proposed solution enhances the polishing removal rate of silicon nitride, allowing for equal removal rates of silicon oxide and silicon nitride, while minimizing defects in the silicon nitride film.
Implementation Method 1
abrasives having a positive zeta potential
Implementation Method 2
a cyclic compound having a mother nucleus with a ring structure and two or more anionic functional groups bonded to the mother nucleus
Data Source
AI summary
There is provided a polishing composition capable of improving the polishing removal rate of silicon nitride to polish silicon oxide and silicon nitride at the same polishing removal rate and polishing silicon nitride with a small number of defects.A polishing composition contains: abrasives having a positive zeta potential; and a cyclic compound having a mother nucleus with a ring structure and two or more anionic functional groups bonded to the mother nucleus, in which the abrasives contain silica. This polishing composition is used for polishing objects to be polished containing silicon oxide and silicon nitride.