Journal article
Quantifying reaction spread and x-ray exposure sensitivity in hydrogen silsesquioxane latent resist patterns with x-ray spectromicroscopy
Journal of vacuum science and technology. B, Nanotechnology & microelectronics, Vol.28(6), pp.1304-1313
2010
DOI: 10.1116/1.3514124
Abstract
Direct-write soft x-ray lithography with an ∼ 50 nm diameter beam is used to pattern features in hydrogen silsesquioxane (HSQ) thin films. Scanning transmission x-ray microscopy of the undeveloped patterns (latent patterns) at the oxygen K -edge reveals a two-stage cross-linking mechanism. Oxygen and siliconnear edge x-ray absorption fine structurespectra of latent patterns show an increase in oxygen content and no change in silicon content within exposed regions. A dose and thickness dependent spatial spread of the cross-linking reaction beyond the exposure boundaries is observed and quantified in detail. Strong area-dependent exposure sensitivity (attributed to cross-linking beyond the exposed region) is observed in latent patterns. A lateral spread in the cross-linking of > 70 nm (full width at half maximum) is observed on both sides of the lines created with 580 eV x-rays ( λ = 2.14 nm ) in 330 ± 50 nm thick HSQ films at low dose ( 0.6 ± 0.3 MGy , 27 ± 12 mJ / cm 2 ) ( 1 MGy = 10 6 J / kg absorbed energy). At a higher dose ( 111 ± 29 MGy , 5143 ± 1027 mJ / cm 2 ), this spread increased to 150 nm. Preliminary results indicate that latent line widths increased with increasing delay between film spin-coating and exposure. Sharper lines are observed after room temperature development of the latent HSQ patterns in NaOH/NaCl solution (onset dose of 3.9 ± 1.0 MGy , 181 ± 36 mJ / cm 2 ) due to the removal of material below a critical degree of cross-linking. Given the short range of low energy secondary electrons in condensed media ( < 10 nm at ≤ 580 eV ), the observed spread is likely due to the propagation of reactive ions or radicals beyond the exposed regions.
Details
- Title: Subtitle
- Quantifying reaction spread and x-ray exposure sensitivity in hydrogen silsesquioxane latent resist patterns with x-ray spectromicroscopy
- Creators
- Allison G CasterStefan KowarikAdam M SchwartzbergStephen R LeoneAlexei TivanskiMary K Gilles
- Resource Type
- Journal article
- Publication Details
- Journal of vacuum science and technology. B, Nanotechnology & microelectronics, Vol.28(6), pp.1304-1313
- DOI
- 10.1116/1.3514124
- ISSN
- 2166-2754
- eISSN
- 2166-2754
- Language
- English
- Date published
- 2010
- Academic Unit
- Chemistry
- Record Identifier
- 9983985979802771
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