Resolution limits due to resist polymer molecular properties

4 Resolution limits due to resist polymer molecular properties 

As shown in Table 17.1, the CD and LER tolerances of resist features are smaller than the dimensions of the polymer molecules in today s resists. A CD of 22 nm is only a small multiple of the radius of gyration in A (rg 0.6 x where 

MW is molecular weight) of typical amorphous polymers used in resists today. And given a typical carbon-carbon bond length of 0.13-0.15 nm, the 2008 ITRS specifications call for near-atomic-scale resolution, which is realistically untenable. Resist material parameters such as the polymerization length distribution, the end-to-end distance, and the radius of gyration, along with the effects 

Castellan, Physical Chemistry, 2nd ed., p. 578, Addison Wesley, Reading, MA (1971). 

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