Polishing Composition Zeta Potential Control for Semiconductor CMP
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Solution Overview
Problem
In semiconductor manufacturing, chemical mechanical polishing (CMP) processes face challenges in minimizing defects and maintaining polishing efficiency due to the adsorption of polishing particles on the substrate surface, which can lead to scratches and residual organic materials that are difficult to remove.
Innovation Solution
A polishing composition with controlled particle size distribution, using metal oxide particles with specific surface modifications and ultrafiltration to inhibit particle adsorption, and a method involving the use of a slurry with a zeta potential range of +10 mV to +40 mV to reduce defects and enhance polishing rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polishing particles are used in CMP process, then polishing rate is improved, but particle adsorption on substrate surface causes defects and scratches
Solution Approach 1:
The patent changes the zeta potential parameter of polishing particles from negative to positive range (+10 to +40 mV), which fundamentally alters their surface interaction properties. This parameter change prevents particle adsorption on the substrate surface while maintaining effective polishing action, thereby resolving the contradiction between achieving high polishing rate and preventing defect formation
Solution Approach 2:
The patent introduces an intermediary substance (polishing composition with specific zeta potential) that mediates between the polishing particles and substrate. This intermediary composition controls particle behavior through electrostatic interactions, enabling particles to remove material effectively without adhering to the substrate, thus preventing scratches and defects while maintaining polishing efficiency
2Manufacturing precision
If polishing particles with small size are used, then surface smoothness is improved, but particle removal becomes difficult
Solution Approach 1:
The patent changes the electrostatic parameter (zeta potential) of small polishing particles to positive values, which fundamentally alters their interaction with the substrate and polishing environment. This parameter modification enables small particles to maintain their size for achieving smooth surfaces while their modified surface properties facilitate easier removal, resolving the contradiction between surface quality and particle removal ease
3Productivity
If polishing composition with high particle concentration is used, then polishing efficiency is improved, but particle adsorption and defect formation increase
Solution Approach 1:
The patent changes the zeta potential parameter of particles in the composition to positive range, which fundamentally alters their collective behavior at high concentrations. This parameter change prevents particle aggregation and adsorption on substrate even at high concentrations, enabling maintained polishing efficiency without increased defect formation
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 effectively inhibits defect formation on the substrate surface by controlling particle size and surface interactions, achieving stable and efficient polishing with reduced scratches and improved removal of polishing particles, thereby enhancing the CMP process.
Implementation Method 1
The polishing particles may be concentrated and purified using an ultrafiltration filter
Implementation Method 2
A zeta potential of the polishing composition may be from +10 mV to +40 mV
Implementation Method 3
a substrate is pressurized and rotated while a slurry is provided to a polishing pad to polish its surface
Data Source
AI summary
A polishing composition for a semiconductor process includes polishing particles. The polishing particles have a Ds value of 700 nm2 to 1400 nm2 according to Equation 1 below; Ds=MPS2−D102 In Equation 1, MPS is a mean particle size of primary particles of the polishing particles. D10 is a particle diameter at a 10% point on a cumulative curve of a particle size distribution of the primary particles of the polishing particles.