Cerium Oxide Polishing Agent for Semiconductor Defect Control
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Solution Overview
Problem
Conventional polishing agents used in semiconductor manufacturing, particularly for chemical mechanical polishing (CMP) in shallow trench isolation (STI), face challenges in achieving high polishing rates while minimizing defects, especially as semiconductor elements become more miniaturized, leading to issues like wiring short circuits and reduced yield.
Innovation Solution
A polishing agent comprising cerium oxide particles with specific characteristics, such as a low index value A derived from infrared absorption spectra and controlled crystallite and primary particle diameters, is used in conjunction with water, along with a polishing method involving a relative motion between the polishing pad and the surface, to enhance polishing efficiency and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cerium oxide particles with small particle diameter are used as abrasive particles, then polishing defect is suppressed, but polishing rate is reduced
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle diameter distribution of cerium oxide particles within a specific range (0.1-10 μm average diameter) and adjusting the pH value (8-11) and composition ratios of the polishing slurry. These parameter optimizations enable the polishing process to achieve both low defect rates and high polishing rates simultaneously, resolving the contradiction between manufacturing precision and productivity.
2Manufacturing precision
If high-purity cerium oxide particles are used, then polishing defect is reduced, but polishing efficiency is worsened
Solution Approach 1:
The patent uses composite material principles by creating a polishing slurry that combines cerium oxide particles with specific additives including surfactants and pH buffers. This composite formulation enhances the polishing efficiency while maintaining the defect-reducing properties of high-purity cerium oxide, thus resolving the contradiction between manufacturing precision and productivity.
3Measurement precision
If miniaturization of semiconductor element advances, then resolution is improved, but polishing defect becomes a larger problem
Solution Approach 1:
The patent applies segmentation by using a controlled distribution of particle sizes in the cerium oxide abrasive mixture rather than a single particle size. This segmented approach allows smaller particles to access and polish finer features in miniaturized structures while larger particles handle broader planarization, thereby maintaining both high resolution and low defect rates as semiconductor elements continue to miniaturize.
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 allows for high polishing rates of silicon oxide films while effectively suppressing polishing defects, thereby improving the manufacturing efficiency and yield of semiconductor devices.
Implementation Method 1
by using chemical mechanical polishing (hereinafter, referred to as CMP)
Implementation Method 2
chemical mechanical polishing (hereinafter, referred to as CMP)
Data Source
AI summary
A first polishing agent contains: cerium oxide particles; and water, wherein, in IR spectrum of the cerium oxide particle, a value A found by a formula below from a ratio (I/I′) between a value I of an absorbance of 3566 cm−1 and a value I′ of an absorbance of 3695 cm−1, and a crystallite diameter XS, is 0.08 or less.A=(I/I′)/XS A second polishing agent contains: cerium oxide particles; and water, wherein, in the cerium oxide particle, a deviation B of a lattice constant found by a formula below from a theoretical lattice constant (a′) and a lattice constant (a) measured by powder X-ray diffraction, is −0.16% or more.B(%)=(1−a/a′)×100