Characterization of line-edge roughness (LER) propagation from resists: underlayer interfaces in ultrathin resist films

George, Simi; Naulleau, Patrick; Krishnamoorthy, Ahila; Wu, Zeyu; Rutter, Edward W.; Kennedy, J.; Xie, Song; Flanigan, Kyle; Wallow, Thomas I.

doi:10.1117/12.848405

Cited by 20 publications

(12 citation statements)

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“…[1][2][3][4] While the theoretical limitations to the RLS trade-off have been well documented, 5,6 this work has all been done at constant film thicknesses. An additional aspect of the RLS trade-off exists that has not been accounted for in these theoretical treatments: as resolution improves, the thickness of resists must concomitantly decrease to prevent line collapse.…”

Section: Introduction 11 Thin-film Ler Problemmentioning

confidence: 99%

LER Limitations of Resist Thin Films

Cardineau

Early

Fujisawa³

et al. 2012

J. Photopol. Sci. Technol.

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This paper describes fundamental studies of the degradation of LER in EUV resists as a function of film thickness. This research focused on the influence of three variables on this LER film thickness problem:  Substrate interaction (primed silicon vs. organic underlayer)  Changes in optical density (variations in fluorine content)  PAG attachment (bound and unbound)Our experimental approach struck a balance between using resists prepared by commercial resist vendors and using open-source resists with custom-designed polymers to address specific variables listed above. One key feature of this research was our development of a mathematical method for evaluation of the extent of the LER deviation in thin films, called φ LER .Our results showed that the effect of substrate was not significant for two different resists (one commercial and one open source). Additionally, we found that increasing optical density actually made the LER degradation (φ LER ) worse-which was contrary to what was predicted by other researchers. Most significant was our demonstration that PAG attachment plays the most important role in the degradation of LER in thinner resist films; polymer-bound PAGs showed a dramatic 3X improvement in φ LER over a similar blended system.

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Section: Introduction 11 Thin-film Ler Problemmentioning

confidence: 99%

LER Limitations of Resist Thin Films

Cardineau

Early

Fujisawa³

et al. 2012

J. Photopol. Sci. Technol.

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“…LWR deteriorates as the photosensitivity is enhanced. Others have also reported high EUV photosensitivity with metal oxide nanoparticle containing photoresists or underlayers [11][12][13]. The metal oxides help generate more secondary electrons from the EUV radiation.…”

Section: Euv Photosensitivity Improvement By Mhmmentioning

confidence: 99%

Progress in Spin-on Hard Mask Materials for Advanced Lithography

Padmanaban

Cho

Kudo

et al. 2014

J. Photopol. Sci. Technol.

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Hard masks used in lithography processes play a vital role in pattern transfer to the desired substrate. Hard mask materials can be categorized into organic and inorganic types. Examples of organic type hard masks include amorphous carbon, organo siloxane based materials with reflection control properties. These organic hard masks are deposited either by CVD process or spin-on processes. SiN, SiON and TiN are some examples of inorganic type hard masks and typically these hard masks are deposited through CVD process. In either type, key requirement is etch resistance to either oxygen rich plasma or halogen rich plasma depending on the substrate to be etched away. However, in the advanced lithography processes, in addition to good etch resistance, they also need to possess good wet removability, fill capability in high aspect ratio contacts and trenches. In this paper, we discuss the advances made in the spin-on organic and inorganic hard masks. The spin-on option provides high throughput and several alternate material options compared to CVD option. Spin-on carbon (SOC) is a high carbon containing polymer solution and as a coating material, the polymers need to be soluble in organic solvent and insoluble after curing for coating upper layer materials. Recent progress made in good filling, low outgas, high thermal stability and planarization properties required for double and quadruple patterning is presented. Similarly, novel spin-on type inorganic formulations providing Ti, W, and Zr oxide hard masks with high etch selectivity, wet removal capability and good shelf-life stability are described. These novel AZ ® Spin-on MHM formulations can be used in several new applications and can potentially replace any metal, metal oxide, metal nitride or silicon-containing hard mask films currently deposited using CVD process in the semiconductor manufacturing process.

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“…Looking at the details of the resist to substrate interface [17], has also suggested that interface properties may be playing a significant role in LER and thus that underlayers might be able to mitigate these effects. Figure 2 shows an off-axis view of features in a leading EUV resist demonstrating a significant increase in LER at the resist to substrate interface and large anisotropy in the spatial scaling characteristics of the LER.…”

Section: Interface Effectsmentioning

confidence: 99%