CMP Composition Zeta-Potential Control for Polysilicon Defect Reduction
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Solution Overview
Problem
Chemical mechanical polishing (CMP) methods using abrasive grains with high hardness often result in polishing scratches and surface defects like dishing on semiconductor substrates containing polysilicon and silicon nitride films, which require a balance between high-speed polishing and minimal defects.
Innovation Solution
A CMP composition comprising abrasive grains with a plurality of protrusions and a liquid medium, where the zeta-potential of the abrasive grains is 10 mV or more, and optionally modified with functional groups such as sulfo, carboxy, or amino groups, to enhance dispersibility and reduce surface defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If abrasive grains with high hardness are used in CMP composition, then polishing rate of polysilicon and silicon nitride films is improved, but polishing scratches and surface defects such as dishing are likely to be generated
Solution Approach 1:
The invention changes the surface charge parameter (zeta-potential) of the abrasive grains from near-neutral or low values to specifically 10 mV or more. This parameter change modifies the electrostatic interaction between abrasive grains and the polishing surface, enabling high-speed polishing while reducing surface defects like scratches and dishing that occur with conventional high-hardness abrasives
Solution Approach 2:
The invention creates a composite polishing system by combining abrasive grains with specific surface charge characteristics (zeta-potential ≥10 mV) with a polishing composition. This composite approach integrates the high hardness needed for fast polishing with controlled surface charge properties that prevent excessive material removal and defect formation
2Productivity
If abrasive grains with high hardness are used to achieve high-speed polishing, then polishing efficiency increases, but the incidence of surface defects such as scratches and dishing increases
Solution Approach 1:
The invention modifies the electrostatic parameter (zeta-potential) of abrasive grains to be 10 mV or more, which changes how the abrasive grains interact with the polishing surface. This parameter adjustment allows maintaining high polishing efficiency while significantly reducing the generation of surface defects, thereby improving surface quality and reliability
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 enables high-speed polishing of semiconductor substrates with reduced surface defects, specifically polysilicon and silicon nitride films, by improving abrasive grain dispersibility and surface interaction, thereby minimizing scratches and dishing.
Implementation Method 1
the absolute value of the zeta-potential of the abrasive grains in the composition for chemical mechanical polishing is 10 mV or more
Data Source
AI summary
A composition for chemical mechanical polishing and a polishing method allow a semiconductor substrate containing at least one of a polysilicon film and a silicon nitride film to be polished at a high speed, while being capable of reducing the incidence of surface defects in the polished surface. The composition for chemical mechanical polishing contains (A) abrasive grains having plural protrusions on their surfaces and (B) a liquid medium, wherein the absolute value of the zeta-potential of the component (A) in the composition for chemical mechanical polishing is 10 mV or more.