A Study of Acid Diffusion Behaviors of PAG by using Top Coat Method for EUVL

Abstract

Semiconductor microfabrication technologies for the 22-nm generation require high-performance resists with superb exposure characteristics. Specifically, this means resolution, exposure sensitivity, and edge roughness values not exceeding 18 nm, 10 mJ/cm 2 , and 2 nm (3), respectively. Resist exposure characteristics must be evaluated using actual exposure spectra. Since six-mirror exposure optics now represents the mainstream, we installed a resist evaluation system [1] capable of obtaining reflectance spectra of these exposure optics at the BL3 beamline in the NewSUBARU [2] synchrotron radiation facility and performed resist evaluations. The system allows evaluations of various parameters for lithography simulations, including exposure sensitivity, [3] acid diffusion length, [4] light desorption characteristics, [5] Dill's ABC parameters, [6] and quenching rate parameters. [7] Using the top coat method, we examined the diffusion behavior of the acid generated by the PAG. This paper reports the results of our study.

Comparison of photoresist sensitivity between KrF, EB, and EUV exposure

“…However, EUV still has various problems in photoresist development. For example, it is well known a trade-off between resolution, LER (Line Edge Roughness) and sensitivity, so-called RLS Trade-off [11][12][13][14][15]. Until now, the development of EUV photoresist has been carried out by EB exposure [16].…”

The measurement of the refractive index n and k value of the EUV resist which used EUV reflectivity measurement method

“…These parameters include development parameters [1] , Dill's C parameter [2][3] , the diffusion length of PAG-derived acids [4] , and parameters for deprotection reactions [5][6] . Through EUV resist simulations based on these parameters, we have examined various conditions for reducing LER and improving resolution [7][8] .…”

The Measurement of the Refractive Index <i>n</i> and <i>k</i> Value of the EUV Resist by EUV Reflectivity Measurement Method

“…These parameters include the development parameter [1], the Dill C parameter [2,3], the diffusion length of acid generated from PAG [4], and the deprotection reaction parameter [5,6]. By using these parameters, we have attempted to simulate EUV resist.…”