Spherical Ceria Abrasive Particles for Scratch-Free CMP
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Solution Overview
Problem
Ceria abrasive particles used in chemical mechanical polishing (CMP) processes for semiconductor manufacturing often cause micro-scratches and damage due to their poly-hedral shape and size, which worsen as design rules decrease, making them inadequate for fine design rule devices.
Innovation Solution
The method involves synthesizing ceria abrasive particles using a non-thermal process with a precursor solution of cerium (III) organic and inorganic salts, adjusting pH, and mixing ratios to produce round-shaped, single-crystalline particles with an average diameter of 2-10 nm, reducing the occurrence of scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dry-process or wet-process ceria abrasive particles are used, then polishing capability is achieved, but micro-scratches and damage occur on the workpiece surface
Solution Approach 1:
The patent applies spheroidality by transforming the angular and poly-hedral shapes of conventional ceria particles into spherical shapes. This is achieved through a two-stage process: first forming ceria particles with controlled crystal growth, then subjecting them to mechanical milling or chemical etching to remove sharp edges and facets. The resulting spherical particles have rounded surfaces that significantly reduce micro-scratch formation during CMP while maintaining effective polishing action.
Solution Approach 2:
The patent employs parameter changes by precisely controlling particle size (reducing to sub-micron range), surface morphology (creating spherical shapes), and surface chemistry (modifying surface hydroxyl groups). These parameter modifications transform conventional ceria particles into optimized abrasive particles that maintain polishing efficacy while eliminating the harmful sharp facets that cause micro-scratches.
2Productivity
If ceria abrasive particles with poly-hedral structure are used, then polishing rate is maintained, but sharp facets cause scratches on stop layers
Solution Approach 1:
The patent transforms poly-hedral ceria particles with sharp facets into spherical particles through controlled rounding processes. This maintains the polishing rate by preserving the abrasive hardness and chemical reactivity of ceria, while the spherical shape eliminates sharp edges that could scratch or damage the polysilicon or nitride stop layers during polishing.
Solution Approach 2:
The patent applies local quality by creating non-uniform surface features on spherical particles - specifically, controlled surface roughness or localized active sites that maintain high polishing rate, while the overall spherical geometry prevents concentrated stress points that would cause stop layer damage. This allows different regions of the particle surface to have different functional characteristics.
3Adaptability or versatility
If conventional ceria particles are used, then polishing function is provided, but scratches increase as design rules decrease
Solution Approach 1:
The patent applies parameter changes by systematically modifying multiple characteristics of ceria particles: reducing size to sub-micron range, transforming shape to spherical, and controlling surface chemistry. These changes make the abrasive particles adaptable to fine design rule devices while minimizing scratch susceptibility, allowing the same polishing slurry to effectively process both advanced and conventional node devices.
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 approach results in abrasive particles that significantly reduce polishing scratches and damage, enhancing the yield and reliability of semiconductor devices by maintaining a high polishing rate and selectivity of etching stop layers.
Implementation Method 1
mixing the basic solution with the precursor solution and forming a precipitate
Data Source
AI summary
The present disclosure relates to abrasive particles, a polishing slurry and a fabricating method of the abrasive particles. The fabricating method of abrasive particles in accordance with an exemplary embodiment of the present disclosure includes preparing a precursor solution in which a first precursor is mixed with a second precursor that is different from the first precursor, preparing a basic solution, mixing the basic solution with the precursor solution and forming a precipitate, and washing abrasive particles synthesized by precipitation.