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Product Briefing Outline: CyberOptics Semiconductor has introduced its new ‘WaferSense’ Auto Vibration System (AVS), designed to monitor three-axis accelerations and equipment vibration to maximize equipment motion and wafer throughput. In addition, the new system can detect wafer damaging equipment vibrations. 

Problem: Equipment acceleration and vibration pose significant threats to wafer production because of their ability to compromise yield significantly. In the semiconductor environment, where moving stages are used to position silicon wafers, the force used to accelerate the stage can vibrate equipment and cause a shift in the payload and damage to the wafers. High precision and sensitive equipment used in the semiconductor industry have a particularly low tolerance to vibrations, and equipment that fails particle qualifications must be taken off line and recalibrated, slowing down the manufacturing process. In addition, automatic material handling equipment must be monitored to make sure it does not exceed maximum allowable vibration levels to permit optimum equipment performance and yield. Controlling a balance between maximum acceleration and minimum vibration is critical for fab yield.

Solution: The WaferSense AVS is a wireless, wafer-like accelerometer available in a 200mm or 300mm format, designed to move through semiconductor process equipment and automation material handling systems including cassettes, SMIFs and FOUPs to observe and monitor three-axis accelerations and vibrations. It reports x, y and z acceleration, has a range of ±2 G, and can detect wafer slides, slips, bumps, scrapes and rough handling. This information is then sent to a computer via VibeView, the application software bundled with the system. The GUI collects and displays this data similarly to an oscilloscope so that baseline performance can be recorded and periodically monitored for changes. Once the location or absence of contamination sources has been identified, equipment can be swiftly adjusted. Fab engineers can see the effect of adjustments in real time, speeding equipment alignment and setup, and motion parameters can be optimized. Vibration data can be compared not only to past readings but from one tool to another to reduce maintenance and cycle time. Users can get early warning for impending equipment failures and/or verify that normal operation continues. This knowledge helps optimize preventative maintenance plans.

Applications: Monitor three-axis accelerations and equipment vibration on 200mm and 300mm tools.

Platform: The WaferSense AVS is battery operated and runs for approximately four hours per charge. It is clean and vacuum compatible, so there is no need to open the tool and expose process areas to the environment when making adjustments. The product kit includes a vibration sensing wafer, communications link module, VibeView application software, charging clean box, and carrying suitcase. The Auto Vibration System joins the expanding family of WaferSense products that include: the Auto Teaching System (ATS), the Auto Leveling System (ALS) and the Auto Gapping System (AGS).

Availability: October 2007 onwards.