News Article
Change in semiconductor equipment CVD segment redefines metrology drivers
Tevet Process Control Technologies has announced that recent and fundamental changes in the semiconductor Chemical Vapour Deposition (CVD) market segment have abruptly created the demand for high speed, every-wafer integrated metrology.
Tevet Process Control Technologies has announced that recent and fundamental changes in the semiconductor Chemical Vapour Deposition (CVD) market segment have abruptly created the demand for high speed, every-wafer integrated metrology. Tevet's patent pending parallel sensor Integrated Metrology Module (IMM) with a two second per wafer measurement cycle measure every wafer in fast CVD processes. A new generation of CVD and Plasma Enhanced CVD (PECVD) has been introduced that run at 2X the throughput of conventional cluster tools. "Throughputs of over 150 wph and more can now be achieved in standard production for thin film deposition," said Risto Puhakka, President of VLSI Research, Inc. "These throughputs can be sustained for critical films such as the increasingly implemented Anti-Reflective Coating (ARC) layers. With ARC layers, it is critical to control the film thickness to be able to successfully image photoresist in the subsequent lithography step. A small change in film thickness either locally (uniformity) or globally (across wafer) can result in lithography pattern aberrations that ultimately reduce end of line yield. The high speed of these new generation tools means that stand-alone metrology tool sampling plans with over an hour between process and measurement would delay detection times to over 150 wafers. This could result in yield losses running into the hundreds of thousands of dollars per excursion before the conventional metrology sampling scheme would detect the processing error." Fast time-to-detection for process excursions is paramount for high throughput process tools to eliminate exposure to unacceptable levels of scrap and rework. Chamber matching, reliability, processing speed, and single-wafer level tracking and control are among the "factors that impact productivity." The new generation of CVD and PECVD tools' high throughput is largely enabled by processing wafers in multiple chambers in parallel. However, with more wafers being produced on fewer tools, any downtime (due to reliability, chamber matching activity, etc.) significantly increases the risk and severity of production flow and line balance impacts vs. conventional tools.
