Effects of Alternating Aperture PSM Design on Image Imbalance for 65nm Technology

Kroyan, Armen; Liu, Huayu

doi:10.1117/12.467852

Cited by 12 publications

(10 citation statements)

References 5 publications

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“…6,7 In our previous study, we focused on understanding of the image intensity imbalance as a function of various mask and imaging parameters based on rigorous EMF simulations. 1 The results of that work predicted that AAPSM image imbalance correction can be implemented through rule-based application of shifter width biasing combined with optimized undercut size. One of the important findings was that rulebased shifter width biasing could be applied before or after OPC since the shifter size adjustment did not affect the critical dimensions of printed lines.…”

Section: Introductionmentioning

confidence: 97%

Practical approach for AAPSM image imbalance correction for sub-100-nm lithography

Cho¹,

Lin²,

Hsieh

et al. 2003

SPIE Proceedings

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In our previously published work, we investigated alternating-aperture PSM image intensity imbalance as function of various mask and optical parameters using rigorous electro-magnetic field (EMF) simulations. 1 Results suggested that the imbalance could be effectively compensated through application of an optimized combination of undercut and a constant phase-shifter bias. In the effort of development and implementation of a production-ready image imbalance correction methodology, it is important to validate the accuracy of simulation-based predictions through correlation of results to experimental data. For this purpose, a test reticle containing various mask parameters as variables was designed and manufactured. The experimental data was obtained from SEM measurements of the exposed wafers, and results were compared to rigorous EMF simulation data. Based on results obtained, we propose and validate an image imbalance correction methodology to be implemented within the framework of the PSM -OPC manufacturing flow.

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Section: Introductionmentioning

confidence: 97%

Practical approach for AAPSM image imbalance correction for sub-100-nm lithography

Cho¹,

Lin²,

Hsieh

et al. 2003

SPIE Proceedings

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“…For the 65-nm node and beyond, the etched region of the alternating PSM was biased larger than the unetched region to reduce intensity imbalance. , 14,15 Because of aberrations, σ image , MEEF and ∂CD / ∂Z have slightly different values depending on whether f max is positive or negative. The mean value of each quantity at the positive and negative value was taken to represent the value at f max .…”

Section: Calculation Of σ Imagementioning

confidence: 99%

Evaluation of the critical dimension control requirements in the ITRS using statistical simulation and error budgets

2004

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To evaluate the ability to achieve the CD control requirements listed in the International Technology Roadmap for Semiconductors (ITRS) and to set error budget targets for focus, dose, PEB temperature uniformity, and mask CD control, statistical lithography simulation was used. A statistical model of total CD control, including the effects of intrafield and interfield error sources, was developed. The exposure tool settings such as wavelength, NA and partial coherence, focus and dose error budgets, lens aberration levels, mask type and pattern pitch values were determined for each node. Monte Carlo simulation was used to predict the CD error due to intrafield dose and focus errors. The contribution to CD error due to the mask was determined using mask CD control values in the ITRS and a calculated MEEF value at various defocus settings. The contribution to CD error due to PEB temperature variations, across wafer dose variations, and variation of aberrations and flare within the exposure field was also simulated. To meet ITRS CD control targets for 130-nm and 90-nm nodes, an alternating PSM mask is required along with a larger CD printed in resist than indicated in the ITRS. Meeting ITRS CD control requirements for 65-nm node and beyond not possible using assumptions detailed here, even with a near ideal APSM. The simulations predicted that if a relaxed pitch and a larger CD in resist were used at the 32nm node, 193nm immersion lithography in combination with a nearly ideal alternating PSM might provide CD control that is comparable to that obtainable using extreme ultraviolet lithography (EUVL).

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“…The parameter setting of phase shifter height and pattern pitch in the shifter layer strongly affects the CD of printed patterns [7], [8]. The shifter height was varied between 400 nm and 1200 nm.…”

Section: -1 Opc Segment Size Vs Epe Of the Middle Position Of A Linementioning

confidence: 99%

Advanced mask pattern correction method of alternating PSM: improvement of line width uniformity in the shifter length direction

et al. 2004

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We have developed a new pattern correction method to improve the uniformity of gate width and thus transistor characteristics. It is well known that the width of the gate pattern as exposed with an alternating phase shift mask (alt-PSM) varies along the gate width direction, owing to the optical-intensity maxima within the phase shifter regions on both sides of the gate. Since the positions of the maxima depend on the shifter height, the pattern pitch and the illumination conditions (σ and NA), the degree of distortion of the gate length also depends on these factors.We have found that the optimal segment size for optical proximity correction (OPC) of gate distortion also depends on the above factors and should be determined by simulation prior to OPC. From our simulations, shorter segments do not necessarily lead to higher correction accuracy, and the optimal size is strongly related to the degree of distortion. Based on these observations, we propose a novel correction method, in which the look-up table of optimal segment size as a function of shifter height and pattern pitch is referred to in the model-based OPC flow. The advantage of the method has been shown by comparing the correction results to those from the ordinary model-based method, with the latter focusing on the line-end regions where the distortion effects are most remarkable.

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Effects of Alternating Aperture PSM Design on Image Imbalance for 65nm Technology

Cited by 12 publications

References 5 publications

Practical approach for AAPSM image imbalance correction for sub-100-nm lithography

Practical approach for AAPSM image imbalance correction for sub-100-nm lithography

Evaluation of the critical dimension control requirements in the ITRS using statistical simulation and error budgets

Advanced mask pattern correction method of alternating PSM: improvement of line width uniformity in the shifter length direction

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