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There are many commercially available deep-UV resists today that show performance gains above Apex, which has been used in 0.35 micrometers production for some time. In addition there are inorganic antireflection layer (ARL) schemes that can now be used with these newer resists, which were difficult to use with Apex due to substrate sensitivity problems leading to footing. We will require the benefits that these newer deep-UV resists and inorganic antireflection coatings can provide as critical gate dimensions fall below the 0.25 micrometers regime. A key benefit of the use of inorganic layers for antireflection control is the ability to maintain conformality, thus avoiding critical dimension (CD) changes that occur as organic antireflection layers are coated over topography. In this paper we evaluated two of the leading edge positive results in a 0.25 micrometers pilot process on ASML 5500/90 and 5500/300 steppers. We examined basic process characteristics such as depth-of-focus (DOF), exposure latitude, dense/isolated bias, post-exposure delay stability, CD swing effects, and substrate sensitivity. This study shows that the benefits of a new resist on an inorganic ARL are reduced swing effects, decreased post- exposure-bake sensitivity, and improved delay stability, all of which result in improved CD control. A slight decrease in DOF and exposure latitude is observed, however the resultant process latitude is sufficient for sub 0.25 micrometers lithography. Results of other tests as well as data off of the ASML PAS5500/300 are also presented.
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