The drive to smaller, less expensive, and faster devices requires radical changes in material development. The increased
material requirements drive complex processes that in turn drive equipment requirements. For the photolithography area
this demand for improved materials is seen in growing requests for device level-specific tuning of organic bottom antireflective
coatings (BARCs) or photoresists for certain imaging requirements, such as numerical aperture, immersion
conditions, and optical parameters. To test and utilize the myriad of BARC materials, there is a need to install them on a
coater-track quickly and efficiently. Installation typically requires a new filter installation, dispense line cleaning, and
usually a minimum of 8-10 L of material to clear out bubbles and other nuisance defects before coating test wafers. As
the number of materials increases, the ability to quickly prime a new filter becomes increasingly important. In this
study, the Entegris IntelliGen® Mini dispense system was utilized to test various pump priming processes to ultimately
minimize the volume purged to reach a defect baseline. In addition, the impacts of the filter media and filter retention on
priming efficiency were studied. Results show that priming processes that were not matched to the filter in use could
actually cause the defects to increase during the process, thus requiring additional purging to reach baseline, and thereby
negating any time or volume savings. Properly programmed priming recipes reduced the purging time and the purging
volume by 50-70%.
In today's competitive lithography market, resist manufacturers are always striving to create a product to meet
lithographic challenges while maintaining a low inherent defect level. While bulk filtration used in resist manufacturing
removes a majority of the inherent defectivity, point-of-use filtration is still required to ensure that defects are not passed
from the bottle to the wafer. As Moore's law drives lithographers to ever decreasing dimensions, resist manufacturers
must find new ways of filtering their chemistries to make sure that the smallest defects cannot create the biggest yield
detractors. In addition, IDMs must use new innovations to explore point-of-use filtration techniques to protect their
This paper will show the conditions that can reduce defectivity in an immersion lithography scheme. More specifically,
advanced point-of-use filtration techniques, including revolutionary filter membrane technology and advanced filtration
settings, will be explored to understand potential 22nm node defect performance. By thinking ahead about the filtration
needs of the future, resist manufacturers, IDMs, and equipment manufacturers can all work toward an understanding of the complex nature of filtration, ultimately yielding a new, low defectivity regime at the smallest pattern sizes.
Minimizing defects in spin-on lithography coatings requires a careful understanding of the interactions between the spin-on
coating material and the filtration and dispense system used on the coating track. A wet-developable bottom anti-reflective
coating (BARC) was examined for its interaction with polyamide and UPE media when utilizing the Entegris IntelliGen Mini dispense system. In addition, a new method of priming the filter and pump is described which improves
the wetting of the filter media, preventing bubbles and other defect-generating air pockets within the system. The goal is
to establish plumb-on procedures that are material and hardware specific to avoid any defect problems in the coating
process, as well as to gain a better understanding of the chemical and physical interactions that lead to coating defects.
Liquid particle counts from a laboratory-based filtration stand are compared with on-wafer defects from a commercial
coating track to establish a correlation and allow better prediction of product performance. This comparison in turn will
provide valuable insight to the engineering process of product filtration and bottling at the source.