Masks used for sub-20 nm half pitch of devices are required to be defect-free as well as to have more
complicate and smaller patterns. For higher resolution for sub-20 nm device, the masks that can provide wider process
windows on wafers are made using new e-beam resists and new mask materials. An introduction of advanced mask
systems needs methodologies to overcome defect challenges that did not occur at previous mask systems. The defects
should be related with chemical and physical properties from negative and positive e-beam resists or/and new type
blanks used for advanced masks such as EUV or optical masks. As a mask pattern size is shrunken, the masks also have
complicate structures and different surface properties from low end mask systems. Defect removal on the masks is
important even at a develop process among mask manufacturing processes. This paper reports that advanced technology
applications on mask develop processes have been performed to remove defects on the masks. First, a new rinse system
has applied into a mask develop process for defect reduction. Second, a new develop process was also performed to
remove defects on masks. The new develop process combined with the new rinse system has reduced more than 50% of
defects including e-beam resist residue defects and other defects. This paper mainly focuses on defects related to
negative and positive resists on masks and their solutions to reduce or/and remove the defects, which are used for sub-20
nm half pitch of devices, in terms of mask develop process.
Haze is a kind of surface contamination on photomask and lithography optics that made by photochemical reaction. There are many problems in photomask manufacturing, inspection and lithography process because of slowly growing feature of haze. In the photolithography process, the wafer damage has been occurred due to the time dependent growth of haze. In this study, we identified the origin and formation mechanism of haze using accelerated contamination experiments, also developed control methods for haze. From these results we expect that the photocontamination control technology should be developed and been a important part of NGL technology.
Haze is a kind of surface contamination on photomask and lithography optics that made by photochemical reaction. There are many problems in photomask manufacturing, inspection and lithography process because of slowly growing feature of haze. In the photolithography process, the wafer damage has been occurred due to the time dependent growth of haze. In this study, we identified the origin and formation mechanism of haze using accelerated contamination experiments, also developed control method for haze, in which the removal efficiency was confirmed by mass production of photomask. From these results we expect that the photocontamination control technology should be developed and been an important part of NGL technology.
Delay effects were evaluated for various chemically amplified resist (CAR) types in view of exposure conditions, vacuum and atmosphere. Since the mask is exposed in the vacuum chamber for a long period of time, unexpected phenomenon has been emerging in CAR such as pattern degradation, line width variation owing to vacuum delay effect (VDE). In the acetal resist based on ethyl vinyl ether (EVE), the VDE emerges as space CD decrease, while post exposure delay (PED) in an optical process shows space CD increase. Acrylate resist and modified acetal resist are superior in VDE as well as PED to EVE resist. VDE seems to be caused by out-gassing. It can be overcome by choosing out-gassing free chemistry such as acrylate and modified acetal. An over-coating method was evaluated to prevent any volatile materials in CAR from being evaporated in the vacuum, but it is disclosed ineffective to VDE. CAR linearity reaches to 0.2micrometers , and its resist and Cr pattern as well as OPC was equivalent to current e-beam resist, ZEP7000. Finally, we can have achieve 8.3nm CD non- uniformity in 3(sigma) in 135*135 mm2 area that allows beyond 0.13micrometers device mask application.
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