Inspection unmasked
A mask inspection technology, introduced by KLA-Tencor, called Wafer Plane Inspection (WPI), a unique mask inspection technology that provides the versatility in a single system to find all defects on a mask and also s hows the defects that will print on the wafer. Besides overcoming yield critical 32nm mask defect challenges, WPI also operates up to 40% faster than previous inspection systems, potentially reducing the percentage of total mask manufacturing time devoted to inspection.
"32nm-generation mask inspection increasingly requires multiple inspection modes to identify all defects," noted Harold Lehon, vice president and general manager of KLA-Tencor's Reticle and Photomask Inspection Division. "With the TeraScan HR and its WPI capability, maskmakers and chipmakers can now use their inspection system to find all defects of interest, and also accurately distinguish which mask defects are likely to transfer to the printed circuit on the wafer. Using the unique technology of the TeraScanHR, customers have a cost effective, direct link between mask inspection and fab yield."
Using the industry standard TeraScanHR mask inspection platform, advancements in software algorithm and image computing technologies allow users to access three distinct inspection planes, reticle, aerial and wafer. The algorithms responsible for WPI's unparalleled modelling capabilities also offer the unique ability to automatically increase the system's sensitivity in critical regions of the photomask where defects that can reduce chip yield are typically found. Testing performed at multiple customers' sites validates the ability of the system to use a larger and faster inspection pixel size in cases where the conventional mode would have required a smaller inspection pixel for the most advanced node in development, cutting mask inspection time by up to 40% for improved cost of ownership.
WPI has been shown to meet chipmakers' critical 32nm-generation defect sensitivity requirements and the WPI technology is undergoing advanced beta testing in conjunction with leading chipmakers in the US and Taiwan. WPI-equipped systems have been shipped to multiple customers.
