Absorption Spectrometer Calibration for Slurry Concentration
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Solution Overview
Problem
Conventional absorption spectrometers experience measurement errors in the concentration of oxidizing agents in slurry due to varying grain concentrations and light scattering effects in CMP processes for semiconductor manufacturing.
Innovation Solution
An absorption spectrometer that calculates the concentration of the oxidizing agent using a calibration curve prepared from multiple light absorption spectra of grain dispersion liquids with different grain concentrations, reducing the impact of grain concentration on measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional absorption spectrometer measures optical absorption spectrum assuming constant grain concentration, then the measurement process is simple and fast, but measurement error occurs due to light scattering from varying grain concentrations
Solution Approach 1:
The calibration process is transformed by changing parameters from a single-grain-concentration assumption to multiple-grain-concentration measurements. The spectrometer now acquires optical absorption spectra at different grain concentrations and uses ratio calculations to eliminate the grain concentration dependency, thereby achieving accurate concentration measurements without requiring complex additional hardware
Solution Approach 2:
The patent introduces an intermediary calibration process that uses multiple reference measurements at different grain concentrations. This intermediary step creates a ratio relationship that mediates between the variable grain concentration and the target component concentration, allowing accurate measurement while accounting for light scattering effects
2Manufacturing precision
If the concentration of oxidizing agent is highly accurately adjusted for ultrafine metal wiring polishing, then polishing precision improves, but the complexity of concentration control and measurement increases
Solution Approach 1:
The patent replaces complex mechanical concentration control systems with an optical measurement system. Instead of relying on precise mechanical dosing equipment, the invention uses near-infrared absorption spectrometry with a simplified calibration process to accurately determine oxidizing agent concentration, thereby achieving precise polishing control through measurement feedback rather than mechanical precision
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
This approach significantly reduces measurement errors in the concentration of the oxidizing agent by accounting for varying grain concentrations, enabling more accurate polishing control in semiconductor manufacturing.
Implementation Method 1
analyzes the concentration of a predetermined component contained in grain dispersion liquid in which grains are dispersed in liquid, in accordance with absorption spectrometry
Implementation Method 2
a light absorption spectrum obtained by irradiating the grain dispersion liquid with light
Implementation Method 3
the effect of light scattering due to the grains in the slurry gives rise to a measurement error
Data Source
AI summary
The present invention intends to reduce a measurement error in the concentration of a component due to the effect of the grain concentration of grain dispersion liquid. Also, the present invention is one that calculates the concentration of a predetermined component added into grain dispersion liquid in which grains are dispersed in liquid, with use of a light absorption spectrum obtained by irradiating the grain dispersion liquid with light and a preliminarily prepared calibration curve representing the relationship between a light absorption spectrum and the concentration of the predetermined component. Further, the calibration curve is prepared on the basis of multiple light absorption spectra obtained by measuring light absorption spectra of multiple grain dispersion liquids having mutually different grain concentrations for each of mutually different multiple concentrations of the predetermined component.