Product Briefing Outline: InnerSense LTD (a Ricor company) now offers a new wafer handling analysis product, the SMW2, for automated mechanical monitoring of the 300mm semiconductor process tools. The new product offering is based on over 6 years of experience in preventing excursions related to wafers’ micro-cracks and other mechanical defects, as well as providing capabilities to detect worn-out process tool mechanical components and to plan more effective periodic maintenance.
Problem: Wafer handling issues are responsible for about 30% of the overall yield loss in the fab. Collision, skidding, rubbing and abrupt lifting and chucking cause wafer micro cracks, breakage, and backside/edge defects. Any mechanical contact with the wafer is suspected to generate particles. The more aggressive such contact is, the higher the particle size and count are likely to be. In addition, troubleshooting and reactive maintenance of those handling issues impacts tool availability and disrupts production. Periodic monitoring of the entire wafer handling system by means of an instrumented wafer (Smart Wafer) has been shown to pinpoint the root cause of such issues and confirm the effectiveness of a corrective action taken. This method has been adopted and implemented by leading IC manufacturers and equipment suppliers. However, in the existing method the smart wafer is manually loaded from the docking station into a FOUP. This operation requires a special tool for opening the FOUP. It has to be done in a specific area in the clean room, and the wafer needs to be cleaned before the run. In addition the raw data recorded in the old method required expert analysis to return a meaningful diagnosis. This has limited its usage in high-volume manufacturing environment.
Solution: The new product provides customers with the capability of monitoring the process tools mechanical health, using the new “Smart FOUP” which interfaces with the process tools like any standard FOUP. New GUI software includes additional user friendly analysis capabilities, such as automatic SPC tool monitoring, tool-to-tool performance comparisons, and more. The new product employs simplified routines that can be easily implemented in a high volume manufacturing environment with minimal interference with the normal production flow.
Applications: Troubleshooting, monitoring and predicting mechanical failures in any robotic wafer handling system. Could be also used by OEMs to select moving components and improve mechanical design.
Platform: The new Smart Wafer- SMW2- incorporates contact less communication and charging to allow regular robotic handling in and out of the “Smart FOUP”.. In the new product. the docking station is integrated into a dedicated FOUP. The data is downloaded via optical communication and the battery is recharged via induction, so that no mechanical contact is made with the wafer. Hence, the smart wafer can be handled like any other production or test wafer. Gathering periodic readings of every tool on the floor supports historical tracking and comparison of similar tools, enabling closer tool matching for tighter process and equipment control. It also allows harnessing the power of AEC (Automated Equipment Control) for managing the entire line through the central factory data system. Predictive maintenance can be more effective by addressing only the trending up or "out of control" mechanical parts Collaboration between the tool manufacturer and the user in sharing typical vibration signatures and indicative signals may facilitate reliable diagnosis and remote assistance. In the long run such collaboration will inevitably contribute to improving handling system designs and enhancing yields.
Availability: November 2009 onwards.