Impurities

With the development of integrated circuit (IC) manufacturing technology, the line width is as small as 10 nm. This reduction in size and increase in density require simultaneous improvements in pollution control. It is important to control the impurity content of inorganic elements in the wafer. Even ultra-trace impurities can cause device defects.

Alfa Chemistry has the ability to provide customers with wafer impurity analysis services to monitor and control trace element contamination to obtain high-purity wafer substrates. Alfa Chemistry's sophisticated analytical instruments and advanced technology enable you to be rest assured.

Alfa Chemistry's Measurement Methods

In the past few decades, Alfa Chemistry has conducted detailed studies on the impurities in the wafers, and can provide a variety of fast, accurate and sensitive measurement techniques to measure metal contamination in the wafers. Our analysis methods include, but are not limited to, the following:

• Surface Metal Extraction, also known as Vapor Phase Decomposition (SME/VPD)
• Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS)

Detectable Samples Include:

• Silicon wafer substrate. (Other materials can also be tested, such as silicon carbide, silicon nitride, and gallium arsenide.)
• The thin metal film formed on the surface of a wafer by PVD. (Pure metals such as Al, Cu, Ti, Co, Ni, Ta, W and Hf.)
• High-k dielectric materials, including Zr, Hf, Sr, Ta, chlorides and oxides of rare earth elements (REE).
• Other materials used in wafer manufacturing, including metals organic compounds, such as trimethylgallium (TMG), trimethylaluminum (TMA), dimethylzinc (DMZ), tetraethoxysilane (TEOS) and trichlorosilane (TCS).

Alfa Chemistry's Instrument Platforms

Our instrument platforms include, but are not limited to, the following:

• Thermo Scientific^TM Element^TM Series HR-ICP-MS

Element^TM Series HR-ICP-MS performs accurate and reliable quantitative multi-element analysis at the trace level, and has the highest sensitivity. The system covers a concentration range from mg/L to below pg/L, which makes it particularly suitable for semiconductor research.

Testing Standard

• BS ISO 14706-2014 Surface Chemical Analysis. Determination of Elemental Contaminants on The Surface of Silicon Wafers Using Total Reflection X-ray Fluorescence (TXRF) Spectroscopy
• JIS K0160-2009 Surface Chemical Analysis. Collecting Elements and Chemical Methods From the Surface of Silicon Wafer Processing Reference Materials and Their Determination by Total Reflection X-ray Fluorescence (TXRF) Spectrophotometry
• GB/T 24577-2009 Thermal Desorption Gas Chromatography Method for Determination of Organic Pollutants on Silicon Wafer Surface

Reference

1. Chakraborty S, et al. (2017). "Laser ablation ICP-MS for impurity analysis in multicrystalline silicon wafers." Energy Procedia. 124: 24-30.