New TOC Technology for Future Chip Generation

摘要

Total organic carbon (TOC) analysis has proven to be a powerful tool for the evaluation of organic contamination in semiconductor ultrapure water. Improvements in water purification technology have enabled ultrapure water systems to achieve substantially lower levels of TOC over the past thirty years. Furthermore, the Semiconductor Industry Association (SIA) and other standards setting organizations continue to recommend tighter TOC specifications for ultrapure water, in order to minimize defect rates and maximize yields for chip fabrication. In projections for the coming fifteen years, the TOC specifications decrease incrementally from less than 7 parts-per-billion (ppb) to less than 1 ppb. Yet, these specifications are meaningful only if low levels of TOC can be measured accurately. Thus, the need has arisen for TOC instrumentation capable of measuring low levels of TOC accurately. Historically, online TOC instruments have been very difficult to calibrate in-situ. Most users have resorted to a "transfer standard," essentially a comparison with a second pre-calibrated instrument. Furthermore, organic standards in the low ppb and ppt TOC range are virtually impossible to prepare reliably. The method of standard additions has been demonstrated as an analytical tool to verify instrument accuracy. However, performing standard additions with traditional TOC analyzer technology requires precise syringe and flow control apparatus. New TOC monitoring technology features an automated, integrated standard addition apparatus. Using this technology, users are now able to perform automated verification of accuracy, on-line, at TOC levels present in ultrapure water. Data from beta facilities will be discussed, revealing the performance of this new technology in the semiconductor industry.