By Cameron Chai
Novellus Systems recently declared that its Germany-based subsidiary, Peter Wolters, has launched a novel gap computing technology that can be used for double-side polishing (DSP) of prime silicon wafers.
The novel high-precision sensors and software programs ensure extraordinary control of wafer quality and enhanced throughput for the AC2000-P3 system.
Novellus’ Figure 1 shows the impact of gap profile control on the GBIR measurement.
DSP technology will aid in the production of 300 and 450 mm prime silicon wafers as it would be possible to achieve extremely flat wafer sizes. The gap size of the polishing wheel and adequate monitoring during polishing is crucial in ascertaining the total thickness within the wafer and variation in thickness between two wafers (GBIR/TTV).
Understanding the importance of effective control of the polishing wheel during the polishing process, engineers at Peter Wolters have combined multiple features into the latest model of AC-2000P3. Wireless gauges with enhanced accuracy deliver sub-micron precision during the measurement process. This novel sensor technology has been integrated into the upper platen adaptive control (UPAC) platform of Peter Walters and offers rapid response times to analyze differences that occur during polishing.
The polishing process has been transformed with the use of end-point detection capability present in the non-contact sensor. This ensures repeated measuring of individual batch wafer thickness and wafer thickness between batches combined with minimal edge roll-off values (ESFQR). The novel sensor technology uses the company’s software program to accurately determine the ultimate thickness of the wafer. Since the technology eliminates activities that increase polishing time, the system throughput is considerably enhanced.