Coprecipitation Detection of Trace Silicon Species Below ICP-MS Limits
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Solution Overview
Problem
Current methods for detecting trace dissolved silicon-based species in semiconductor manufacturing processes, such as ICP-MS, have a detection limit of about 250 ppt, which is not sufficient for precise analysis.
Innovation Solution
A method involving the conversion of active species into deactivated species, followed by coprecipitation to form a solid species with the target substance, allowing for solid-liquid separation and independent measurement of the target substance concentration, thereby increasing measurement sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ICP-MS is used for detecting trace dissolved silicon-based species, then the detection method is established, but the detection limit is limited to about 250 ppt
Solution Approach 1:
The patent applies preliminary action by performing coprecipitation of silicon-based species with metal hydroxides (such as aluminum, iron, or zirconium hydroxide) before the actual measurement. This preliminary concentration step transforms trace dissolved silicon species into a solid precipitate form, increasing their concentration from ppt level to detectable levels. The metal hydroxide acts as a carrier that precipitates silicon species together, enabling subsequent measurement to achieve detection limits below 250 ppt, thus resolving the contradiction between measurement precision and detection sensitivity.
2Reliability
If direct measurement of trace silicon-based species is performed, then the measurement process is simple, but the detection sensitivity is insufficient
Solution Approach 1:
The patent introduces metal hydroxide (aluminum, iron, or zirconium hydroxide) as an intermediary substance that facilitates the detection of trace silicon-based species. The metal hydroxide acts as a mediator by coprecipitating with silicon species, effectively concentrating them into a measurable form. This intermediary approach enhances detection sensitivity without requiring complex instrumentation modifications, as the coprecipitation process can be performed using standard chemical reagents followed by conventional measurement techniques.
Solution Approach 2:
The patent applies parameter changes by altering the physical and chemical state of silicon-based species from dissolved trace form to solid precipitate form through coprecipitation. This parameter change transforms the concentration level from ppt (parts per trillion) in solution to a much higher concentration in the solid precipitate, making the species detectable by standard analytical instruments. The phase transition and concentration enhancement resolve the sensitivity issue while maintaining procedural simplicity.
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 method significantly enhances the detection sensitivity of trace silicon-based species by isolating and concentrating them in a solid form, enabling accurate measurement beyond the limitations of existing techniques like ICP-MS.
Implementation Method 1
converting the active species into a deactivated species
Implementation Method 2
concentrating the target substance into a solid species by coprecipitation
Implementation Method 3
separating the solid species from the deactivated species by solid-liquid separation
Data Source
AI summary
An method for detecting a target substance includes providing a sample including the target substance and an active species, converting the active species into a deactivated species, adding a reactive agent into the sample to form a solid species including the target substance, separating the solid species from the deactivated species by solid-liquid separation, and determining a concentration of the target substance in the sample by measuring a concentration of the target substance in the solid species.