Metal Impurity Analysis on Semiconductor Substrates
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Solution Overview
Problem
Current methods for measuring metal impurities on semiconductor substrates, particularly those with low content, are inaccurate and inefficient, hindering the development of liquid chemicals with excellent defect inhibitive performance due to insufficient sensitivity of conventional total reflection X-ray fluorescence analysis methods.
Innovation Solution
A method involving the concentration of a sample containing organic solvents and metal impurities, followed by coating a substrate and using total reflection X-ray fluorescence analysis to measure metal atoms per unit area, with optional steps of contacting with hydrogen fluoride gas or a solution containing hydrogen fluoride and hydrogen peroxide to enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional total reflection X-ray fluorescence analysis method is used to measure metal impurities on substrate, then the measurement process is simple, but the measurement precision is insufficient for low content metal impurities
Solution Approach 1:
The patent applies preliminary action by concentrating the sample before measurement. The analysis method includes a concentration step performed before the measurement step, where the sample containing metal impurities is concentrated at a predetermined rate to obtain a concentrated liquid. This preliminary concentration action enhances the metal impurity content to a level detectable by conventional X-ray fluorescence analysis, thereby improving measurement precision without requiring more complex measurement equipment.
2Measurement precision
If sample is concentrated before measurement, then the measurement precision improves, but the process complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the concentration parameter of the sample. The concentration step changes the concentration parameter of metal impurities in the sample from a low initial state to a high concentrated state. This parameter transformation enables conventional measurement equipment to achieve high measurement precision while keeping the process relatively simple, as concentration is a standard laboratory operation.
Solution Approach 2:
The patent introduces an intermediary substance or process in the concentration step. The sample is concentrated using intermediary methods (such as evaporation, filtration, or chemical precipitation) that facilitate the accumulation of metal impurities. This intermediary concentration process acts as a bridge between the low-concentration original sample and the measurement capability of conventional equipment, improving precision without requiring complex measurement devices.
3Reliability
If liquid chemical has low metal impurity content, then the defect inhibitive performance improves, but the measurement accuracy deteriorates
Solution Approach 1:
The patent resolves this contradiction by applying preliminary concentration action before measurement. Even though the liquid chemical has low metal impurity content (which is good for defect inhibitive performance), the concentration step preliminarily enriches the metal impurities to a measurable level. This allows accurate measurement of low-concentration impurities without altering the original low-impurity state of the liquid chemical, thereby maintaining both reliability and measurement 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 allows for simple and accurate measurement of metal impurities, enabling the evaluation of defect inhibitive performance and production of liquid chemicals with improved purity and reduced defect generation on semiconductor substrates.
Implementation Method 1
a total reflection X-ray fluorescence analysis method in which excitation X-rays are incident on the surface of a measurement sample formed of a semiconductor single crystal at an angle equal to or less than the total reflection angle, the amount of fluorescent X-rays from the surface metal impurities of the measurement sample, which are generated by the excitation, is measured
Implementation Method 2
a step A of concentrating a sample containing at least one organic solvent and a metal impurity containing a metal atom at a predetermined rate to obtain a concentrated liquid
Implementation Method 3
a step B of coating a substrate with the concentrated liquid to obtain a coated substrate
Data Source
AI summary
An object of the present invention is to provide an analysis method in which a simple and accurate measurement result can be obtained even in a case where a sample (particularly, a sample having a low content of metal impurities) is coated on a substrate and the amount of metal impurities per unit area on the substrate is measured, a liquid chemical, and a method for producing a liquid chemical. The analysis method of the present invention includes: a step A of concentrating a sample containing at least one organic solvent and a metal impurity containing a metal atom at a predetermined rate to obtain a concentrated liquid; a step B of coating a substrate with the concentrated liquid to obtain a coated substrate; and a step C of measuring the number of the metal atom per unit area on the coated substrate by using a total reflection X-ray fluorescence analysis method and obtaining a measured value.