Rapid detection of impurity particles in etching solutions using electrospray-differential mobility analysis.

Area of Science:

• Materials Science
• Analytical Chemistry
• Chemical Engineering

Background:

• Particle defects in semiconductor processing chemicals significantly reduce yield and quality.
• Early detection and removal of impurities in solutions like etchants are critical for advanced manufacturing.
• Existing methods struggle to detect and quantify specific organic impurities in complex chemical matrices.

Purpose of the Study:

• To develop and validate a novel electrospray-differential mobility analysis (ES-DMA) methodology.
• To enable sensitive detection and quantification of specific organic impurity particles in semiconductor etching solutions.
• To improve quality control in semiconductor manufacturing through early contaminant identification.

Main Methods:

• Utilized electrospray ionization (ES) to generate fine, uniform droplets from simulated etching solutions, effectively removing co-solvents.
• Employed differential mobility analysis (DMA) for the size-based separation and detection of charged particles.
• Applied ES-DMA to identify and quantify model organic impurities like polyethylene glycol (PEG100K) and bovine serum albumin (BSA).

Main Results:

• Successfully detected and quantified ultrafine organic impurity particles smaller than 10 nm.
• Achieved a low detection limit of 10 ppm for organic contaminants.
• Demonstrated effective analysis even in the presence of high concentrations of nonvolatile solutes, such as 2 wt% citric acid.
• Validated the method's capability to isolate and analyze specific organic impurities within complex chemical mixtures.

Conclusions:

• The ES-DMA method offers a powerful new tool for detecting trace organic contaminants in semiconductor processing chemicals.
• This technique significantly enhances the potential for early-stage quality control in semiconductor manufacturing.
• The ability to identify specific organic impurities at low concentrations promises to improve overall product quality and manufacturing yield.