Exposing extreme ultraviolet lithography at Intel

Roberts, J. M.; Bacuita, Terence; Bristol, Robert; Cao, Heidi B.; Chandhok, Manish; Lee, Sang H.; Leeson, Michael J.; Liang, Ted; Panning, Eric M.; Rice, Bryan J.; Shah, Uday; Shell, Melissa; Yueh, Wang; Zhang, Guojing

doi:10.1016/j.mee.2005.12.037

Cited by 18 publications

(11 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Extreme ultraviolet (EUV) lithography is being developed as a potential successor to 193 nm lithography for printing the smallest microprocessor features. 1 Resists developed for EUV lithography are typically based on modifications to materials or formulations developed for other lithographic exposures, specifically 248 nm, 193 nm, and e-beam. 2 Although much is known about the actinic radiation-induced chemistry at traditional advanced lithographic optical wavelengths (157 to 248 nm), little work has been performed at the 13.4 nm wavelength used for EUV.…”

Section: Introductionmentioning

confidence: 99%

Polymer photochemistry at the EUV wavelength

et al. 2010

View full text Add to dashboard Cite

The higher energy associated with extreme ultraviolet (EUV) radiation coupled with the high absorptivity of most organic polymers at these wavelengths should lead to increased excited state population and higher quantum yields of photoproducts. Polymers representative of those commonly employed in resists as well as some model polymers were selected for this study. Polymer photochemistry at EUV was catalogued as to the effect of absorbed 13.4-nm radiation on a polymer's quantum yield of chain scission (Φ s) and crosslinking (Φ x). In selected cases, the chain scission and crosslinking quantum yields were also compared to those previously determined at 157-, 193-and 248-nm. It was found that quantum yield values were over a magnitude greater at EUV relative to optical wavelengths.

show abstract

Section: Introductionmentioning

confidence: 99%

Polymer photochemistry at the EUV wavelength

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Stochastic resist models were built using PROLITH X3.2 and model calibration methods developed by KLA-Tencor. For the EUV simulations, aerial images have been corrected for the estimated flare based on the local absorber coverage of the reticle, the flare as determined from Kirk disappearing pad test (2μm) and the point spread function of the optics [10].…”

Section: Methodsmentioning

confidence: 99%

EUV secondary electron blur at the 22nm half pitch node

et al. 2011

View full text Add to dashboard Cite

In this paper the Arrhenius behavior of blur upon EUV exposure is investigated through variation of the PEB temperature. In this way, thermally activated parameters that contribute to blur (such as acid/base diffusion) can be separated from non-thermally activated parameters (such as secondary electron blur). The experimental results are analyzed in detail using multi-wavelength resist modeling based on the continuum approach and through fitting of the EUV data using stochastic resist models. The extracted blur kinetics display perfectly linear Arrhenius behavior, indicating that there is no sign for secondary electron blur at 22nm half pitch. At the lowest PEB setting the total blur length is ~4nm, indicating that secondary electron blur should be well below that. The stochastic resist model gives a best fit to the current data set with parameters that result in a maximum probability of acid generation at 2.4nm from the photon absorption site. Extrapolation of the model predicts that towards the 16nm half pitch the impact on sizing dose is minimal and an acceptable exposure latitude is achievable. In order to limit the impact on line width roughness at these dimensions it will be required to control acid diffusion to ~5nm.

show abstract

“…The 248 nm exposures were performed with a Canon EX-4 248-nm 0.6 NA stepper employing a KrF laser. The EUV exposures at 13.5 nm were performed on Exitech Microexposure tools equipped with a 180 nm silicon membrane spectral purity filter to block the DUV wavelengths; the model polymers were exposed at Sematech in Albany, NY and the commercial polymers at Intel in Hillsboro, OR 2 . The commercial resists were exposed at all of the above wavelengths.…”

Section: Exposurementioning

confidence: 99%

“…EUV Lithography is being developed as a potential successor to 193 nm lithography for printing the smallest microprocessor features 2 . Resists developed for EUV are typically based on modifications to materials developed for other lithographic exposures, specifically 248 nm, 193 nm, and e-beam 3 .…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of EUV resists to out-of-band radiation

Roberts

Bristol

Younkin

et al. 2009

Advances in Resist Materials and Processing Technology XXVI

Self Cite

View full text Add to dashboard Cite

Here we present the relative sensitivity of EUV resists to out of band radiation (OOB), specifically wavelengths in the range 157 -400 nm. EUV light sources have specifications limiting the allowed energy output in that spectral range yet there is little data supporting the specified values. Filters might be required to meet the spectral purity specifications which will likely have the detrimental effect of reducing the in-band radiation at 13.5 nm and therefore negatively impact the cost of ownership of EUV lithography. To better quantify the effects of OOB we obtained contrast curves and absorbance spectra for several EUV resist platforms at nine exposure wavelengths. The 2007 ITRS Roadmap suggests that resist thicknesses will be near 35 -65 nm when EUV will be used 1 . We found that, in this optically thin regime, resist sensitivity increases with increasing absorbance. The sensitivity decreases dramatically for wavelengths approaching 300 nm, and is negligible for longer wavelengths. The OOB sensitivity of the resists examined can be estimated to within an order of magnitude using the resist absorbance value. For resists with absorbance values on the same order of magnitude, sensitivity is determined by other aspects of the resist formulation. Within the wavelength region explored, the greatest concern is near 160 -240 nm based on current resist sensitivity characteristics. However, there is a gap in data between 13.5 -157 nm and there may be other reasons to limit the source output in that wavelength range. The data presented here could be useful in setting or modifying the OOB specifications for EUV tools.Keywords: Extreme Ultraviolet Lithography, EUVL, Resist, Sensitivity, out-of-band, spectral purity INTRODUCTIONEUV Lithography is being developed as a potential successor to 193 nm lithography for printing the smallest microprocessor features 2 . Resists developed for EUV are typically based on modifications to materials developed for other lithographic exposures, specifically 248 nm, 193 nm, and e-beam 3 . Therefore, EUV resists are sensitive to radiation other than 13.5 nm, as has been demonstrated [4][5][6] . EUV sources produce light over a wide spectral range [7][8][9][10] . The multilayer coated (MLC) mirrors used in the optics are effective at narrowing the EUV spectral output to peak at 13.5 nm with a bandwidth of ±2%. However, the mirrors also reflect other wavelengths. If OOB light produced by the source reaches the wafer plane, and the resist is sensitive to that light, then contrast will be reduced resulting in degraded imaging performance 6 . The purpose of this study is to characterize the sensitivity of typical EUV resists to OOB radiation. Mbanao et al. measured the sensitivity of 4 resists in the spectral range 190-650 nm 5 . The study presented here extends the spectral range down to 157 nm and includes a wider breadth of resist types with data collected on 13 different materials. Moreover, all resists in this study were 60 nm thick (which is expected to be relevant when EUV is i...

show abstract

Exposing extreme ultraviolet lithography at Intel

Cited by 18 publications

References 18 publications

Polymer photochemistry at the EUV wavelength

Polymer photochemistry at the EUV wavelength

EUV secondary electron blur at the 22nm half pitch node

Sensitivity of EUV resists to out-of-band radiation

Contact Info

Product

Resources

About