Study of iso-dense bias (IDB) sensitivity to laser spectral shape at the 45nm node

Yoshimochi, Kazuyuki; Uchiyama, Takayuki; Tamura, Takao; Theeuwes, Thomas; Peeters, Rudy; Laan, Hans van der; Bakker, H.; Oga, Toshihiro

doi:10.1117/12.711052

Cited by 9 publications

(2 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Current practical tolerances for OPC error due to bandwidth variation at the 45nm node are less than 1nm, [8] resulting in sub-100fm (1 femtometer = 10 -15 m) E95 bandwidth variation tolerances. Surpassing this level of bandwidth control can only be realized using active control enabled by highprecision E95 metrology, which is available on-board the latest generation laser systems.…”

Section: Laser Bandwidth Stability and Metrologymentioning

confidence: 99%

Fast and accurate laser bandwidth modeling of optical proximity effects

Lalovic¹,

Kritsun

Bendik³

et al. 2007

SPIE Proceedings

View full text Add to dashboard Cite

In this work, we model the effects of excimer laser bandwidth on optical proximity effects in high-NA ArF dry and immersion lithography. We quantify the errors introduced by using common approximation methods for the laser spectrum, such as the modified Lorentzian and Gaussian forms. Although these approximations are simple to use, and their symmetry properties can lead to reduced simulation run-times, they typically induce significant CD error when compared to the use of measured spectral profiles, which are obtained from high-resolution spectrophotometry. In this paper we establish some accuracy benchmarks and demonstrate the need for inclusion of information about the spectral profile-for the laser type of interest-in order to achieve sub-nanometer image calculation accuracy required for optical proximity correction. We further assess the speed-accuracy tradeoffs in terms of data truncation and sampling, and propose some practical limits for sampling the illumination spectrum.Additionally, in this work, we propose a new physically-based spectrum approximation method, which significantly reduces computation time at a cost of less than 0.25nm residual image-CD error from the fully-sampled image calculation. In addition to aerial image, we compare 45nm-node calibrated resist models and latent image results for 0.92NA dry and 1.2NA immersion processes using measured illumination profiles and lens aberrations. Finally, we consider the laser bandwidth sensitivity of 2D lineend patterns and typical post-OPC designs for a logic gate-process.

show abstract

Section: Laser Bandwidth Stability and Metrologymentioning

confidence: 99%

Fast and accurate laser bandwidth modeling of optical proximity effects

Lalovic¹,

Kritsun

Bendik³

et al. 2007

SPIE Proceedings

View full text Add to dashboard Cite

show abstract

“…It is well known that the finite laser bandwidth in modern 193 nm systems causes the energy in the focus plane to become spread out, an effect commonly known as focus blur [1] [2] [3]. It has also been shown previously that structures which are more sensitive to defocus will have higher sensitivity to variations of the laser bandwidth [4] [5]. The resulting effect of changes in laser bandwidth is a featuredependent bias that can be as large as several nanometers for the focus-sensitive isolated or semi-isolated structures if the bandwidth variation is not actively stabilized.…”

Section: Introductionmentioning

confidence: 99%

Modeling laser bandwidth for OPC applications

et al. 2009

View full text Add to dashboard Cite

With the push toward 32 nm half-pitch, OPC models will need to account for a wider range of sources of imaging variability in order to meet the CD budget requirements. The effects of chromatic aberration on imaging have been a recent area of interest but little work has been done to include this effect in OPC models. Chromatic aberrations in the optical system give rise to a blurring of the intensity distribution in the imaging plane even for highly line-narrowed immersion laser sources. The resulting focus blur can introduce a feature-dependent CD bias of several nanometers. Usually, the empirical components of the resist model can reduce or completely compensate for this imaging effect. However, it is not well known if including a more physical image model over a large range of laser bandwidth conditions will improve the OPC accuracy or process-variability robustness.This study demonstrates the correlation of physical laser bandwidth perturbations with perturbations of the optical model in Calibre. The laser bandwidth is experimentally perturbed to obtain several sets of CD measurements for different bandwidths. These are then used in model calibration with the corresponding perturbation in the optical model. Finally, we quantify the improvement in model accuracy obtained when including an input of laser bandwidth.

show abstract

High Index Resist for 193 nm Immersion Lithography

et al. 2008

View full text Add to dashboard Cite

Leading edge semiconductor products are made by immersion lithography at 193 nm using water as a fluid medium. This imaging process enables production of 45 nm features. Extending immersion lithography to 32 nm or below requires increases in the refractive indices of the lens material, the immersion fluid, and the resist material. Future generations of resist materials require a refractive index approaching 1.9 at 193 nm. It is known that incorporation of sulfur atoms increases the refractive index of polymers. However, increasing the refractive index is normally linked to a corresponding increase in the absorbance. In attempt to design resist polymers with a high refractive index and low absorbance, we studied several new sulfur-containing monomers and polymers and found functionality that can increase the refractive index without increasing the absorbance at 193 nm. New thioester and sulfone structures are particularly useful in that regard. These new monomers have been used produce imageable polymers with a refractive index of 1.8 at 193 nm and an absorbance less than 1.4 µm−1.

show abstract

Study of iso-dense bias (IDB) sensitivity to laser spectral shape at the 45nm node

Cited by 9 publications

References 4 publications

Fast and accurate laser bandwidth modeling of optical proximity effects

Fast and accurate laser bandwidth modeling of optical proximity effects

Modeling laser bandwidth for OPC applications

High Index Resist for 193 nm Immersion Lithography

Contact Info

Product

Resources

About