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Accurate identification of process windows can be accomplished using KLA-Tencor’s fixed focus offset conditions and Process window Discovery (PWD) methodology[1]. The PWD methodology makes use of a modulated wafer layout to enable inspection comparing nominal to modulated conditions. KLA-Tencor’s Broadband plasma (BBP) inspection technology is used to compare the nominal conditions to each experimental condition and to identify systematic defects. The identification of systematic defects is enabled by the PWD method by first discovering potential patterns of interest and then generating NanopointTM care areas around every occurrence of the patterns of interest. This allows identification of critical systematic structures that may have the same design intent but do not repeat in the same X,Y locations within a device. This approach maximizes the inspection sensitivity on each structure type, accurately identifies the edge of the process window in focus and dose, and enables study of the sensitivity of fixes process offsets (such as light source bandwidth).
In this study, a tunable DUV light source bandwidth technique and the PWD methodology are used to study the light source E95 bandwidth impact on Metal layer features from an imec 10 nm node logic-type test vehicle.
In this study, the authors focus on the increase in image contrast that Source Mask Optimization (SMO) and Optical Proximity Correction (OPC) models deliver when comparing 300 fm and 200 fm light source E95% bandwidth. Using test constructs that follow current N7 / N5 ground rules and multiple pattern deconstruction rules, improvements in exposure latitude (EL), critical dimension (CD) and mask error enhancement factor (MEEF) performance are observed when SMO and OPC are optimized for 200 fm light source bandwidth when compared with the standard 300 fm bandwidth. New SMO-OPC flows will be proposed that users can follow to maximize process benefit. The predicted responses will be compared with the experimental on wafer responses of 7 nm features to lower light source bandwidth.
Recent improvements in bandwidth control have been realized in the XLR platform with Cymer’s DynaPulseTM control technology. This reduction in bandwidth variation translates in the further reduction of CD variation in device structures 5,6. The Authors will review the methodology for determining the impact that bandwidth variation has on CD dose, focus, pitch and bandwidth, which is required to build a dynamic model. This assists in understanding the impact that bandwidth variability has on the accuracy of the Source and Mask optimization and the overall OPC model, which is reviewed and demonstrated.
The majority of chipmakers are putting light source data generated by tools such as Cymer OnLine (COL), OnPulse Plus, and SmartPulse to good use. These data sets, combined with in-depth knowledge of the equipment, makes it possible to draw powerful conclusions that help increase both chip manufacturing consistency as well as equipment productivity. This discussion will focus on the latter, equipment availability, and how data analysis can help increase equipment availability for Cymer customers.
There are several types of opportunities for increasing equipment availability, but in general we can focus on two primary categories: 1) scheduled downtime and 2) unscheduled downtime. For equipment that is under control of a larger entity, as the laser is to the scanner, there are additional categories related to either communication errors or better synchronization of events that can maximize overall litho-cell efficiency. In this article we will focus on general availability without highlighting the specific cause of litho-cell (laser, scanner and track). The goal is to increase equipment available time with a primary focus is on opportunities to minimize errors and variabilities.
Recent improvements in bandwidth control have been realized in the XLR platform with Cymer’s DynaPulseTM control technology. This reduction in bandwidth variation could translate in the further reduction of CD variation in device structures. The Authors will discuss the impact that these improvements in bandwidth control have on advanced lithography applications. This can translate to improved CD control and higher wafer yields. A simulation study investigates the impact of bandwidth on contrast sensitive device layers such as contacts and 1x metal layers. Furthermore, the Authors will discuss the impact on process window through pitch and the overlapping process window through pitch that has been investigated. These improvements will be further quantified by the analysis of statistical bandwidth variation and the impact on CD.
New ArF immersion light source introduces technologies for high-volume 14nm manufacturing and beyond
