VPD-ICP-MS Semiconductor Wafer Metal Contamination Analysis

Currently, the commonly used surface contamination analysis techniques for VPD wafer metal contamination are VPD-ICP-MS and TXRF.

The commonly used analysis techniques for monitoring metal contamination in silicon wafers include VPD-ICP-MS. Based on the type of instrument and analytical methods, different monitoring schemes for silicon wafer metal contamination have been compared.

Figure 1. Silicon Wafer Metal Contamination Monitoring Schemes

TXRF is an ideal choice for high-throughput analysis, as its measurement principle is based on the interaction between an electron beam and the silicon wafer surface, requiring no chemical pre-treatment. This technique allows for the rapid analysis of both routine elements and precious metal elements in an automated mode and can use the mapping function to locate localized contamination on the wafer surface. However, TXRF has a relatively high lower limit of detection (LLD), approximately 1E9~1E11 atoms/cm², as shown in Figure 2.

Figure 2. Comparison of TXRF Detection Limits

However, the detection limits of VPD-ICP-MS vary significantly. Because the VPD technique is based on chemical principles and different technical routes, the calculation methods for the detection limits in ICP-MS also differ (Figure 3).

Figure 3. VPD-ICP-MS Technical Details and Detection Limit Determination

Figure 4 shows that the detection limits of VPD-ICP-MS range from 1E6 to 5E9 atoms/cm², which are much lower than those of TXRF. However, the detection limits of VPD-ICP-MS are influenced by technical details and differences in experimental environments. Operators must manually transfer bottles containing the scanning solution to the ICP-MS/MS (Agilent), and the sample bottles need to be manually cleaned before collection. These steps can increase the likelihood of contamination by Na, Mg, and Ca. A cleanroom environment ensures that the detection limits for easily contaminating elements remain below 1E10 atoms/cm². If fully automated VPD can be used, the detection limits would further improve.

Figure 4. Comparison of VPD-ICP-MS Detection Limits (Surface)

Regarding VPD metal contamination, we have conducted professional technical analysis. Firstly, using the silicon wafer surface contamination technique VPD-ICP-MS, we analyze precious metal elements and conventional elements of the wafer using multiple chemical solutions, without mapping functionality. VPD silicon wafer surface contamination technology helps businesses to improve their understanding of elemental detection limits. Through professional means, we analyze the minimum concentration of elements and control metal contamination to crucial low levels, providing businesses with comprehensive VPD silicon wafer metal contamination detection services.