Optimization of Polymer-bound PAG (PBP) for 20nm EUV Lithography

Abstract

This paper discusses the continued evolution of Polymer-bound PAG [PBP] resists for sub-20nm lithography. Utilizing EUV wavelength, there has been enough progress in resolution and sensitivity to justify the use of these materials. PBP resists have shown that the principal demerit of acid diffusion can be overcome through attachment of the PAG anion to the lithographic polymer. Since the introduction of this chemically amplified resist approach, we have seen steady improvement in resolution, sensitivity, and LWR. Using a 0.30NA EUV tool with dipole, we can achieve 22nm hp resolution, with 12mJ dose, and 4.2nm LWR. Through rational PAG cation design, we have substantially reduced to a factor of 1/10th the PBP resist response to Out-of-Band Radiation compared to a TPS-based PBP. In this way, the resist can act as in situ spectral filter for unwanted longer wavelength exposure.

Dissolution Characteristics of EUV Resist by High Speed AFM

“…[3] Fig. 5 The pattern CD variation (ratio) of the 32-nm I/L for (a) methacryl-based, (b) PHS-based and (c) hybrid resists during the rinse process using D.I.W. For this methacryl-based resist, pattern CD increase by as much as 20% was observed.…”

“…On material research, continued investigations on conventional [2][3] and alternative chemistries such as; low molecular [3] , photo acid generator (PAG)-bound [4][5] , inorganic resists [6][7] , etc. have shown potential results.…”

Extending the scope of poly(styrene)-block-poly(methyl methacrylate) for directed self-assembly

“…A key aim for the development of photoresists and associated processes is to simultaneously improve RLS. Many gains can be made by optimisation of resist formulations, although more disruptive technologies include the redesign of the resists and such approaches include: polymer bound PAG resists, [1][2][3][4][5][6][7] molecular glass resists [8][9][10][11][12][13][14][15][16] and chain scissioning resists. [17][18][19][20][21][22][23][24][25][26] In particular, polymer bound PAG resists have achieved a great deal of success as EUVL platforms, although improvements are still required for achieving the ITRS goals.…”

Healing LER using directed self assembly: treatment of EUVL resists with aqueous solutions of block copolymers

“…Apart from resist optimisation, more radical solutions include polymer bound PAG resists, [1][2][3][4][5][6][7] molecular glass resists [8][9][10][11][12][13][14][15][16] and chain scissioning resists. [17][18][19][20][21][22][23][24][25][26] Polymer bound PAG resists, in particular, have been successful in EUVL, although improvements are still required for achieving the ITRS goals.…”