Generation of arbitrary freeform source shapes using advanced illumination systems in high-NA immersion scanners

Zimmermann, Jörg; Gräupner, Paul; Neumann, Jens Timo; Hellweg, Dirk; Jürgens, Dirk; Patra, Michael; Hennerkes, Christoph; Maul, Manfred; Geh, Bernd; Engelen, André; Noordman, O.F.J.; Mulder, Melchior; Park, Sean S.; Vocht, Joep De

doi:10.1117/12.847282

Cited by 24 publications

(10 citation statements)

References 16 publications

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“…In practice, the illuminator is nonideal, and the source blur is inevitable in the lithography process [15,16]. Here, the blurring source is a convolution between the ideal effective source and a normalized Gaussian kernel, and is formulated as…”

Section: Lithography Vectorial Imaging Modelmentioning

confidence: 99%

Robust hybrid source and mask optimization to lithography source blur and flare

Han

et al. 2015

Appl. Opt.

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As a promising resolution enhancement technique, a set of pixelated source and mask optimization (SMO) methods has been introduced to further improve the lithography at 45 nm node and beyond. Recently, some papers studied the impact of the scanner errors on SMO, and the results revealed that the source blur and flare seriously impact on the lithography performance of the optimal source and mask resulting from SMO. However, current SMO methods did not propose an effective method to compensate for the impact of these nonideal factors of the actual scanners. To overcome this drawback, this paper focuses on developing a robust hybrid SMO (HSMO) method where the sensitivities of the aerial image to source blur and flare are introduced into the cost function. Simulation results are compared with traditional SMO to demonstrate the benefit of the proposed source blur-flare-aware HSMO method in pattern fidelity and process window.

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Section: Lithography Vectorial Imaging Modelmentioning

confidence: 99%

Robust hybrid source and mask optimization to lithography source blur and flare

Han

et al. 2015

Appl. Opt.

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“…Some methods have been used to obtain the different sources, such as pupil filtering 11 , DOE 12 and micro mirrors array 13 . Nowadays, the DOE is the most widely used method as the loss light of the pupil filtering is tremendous and it is too difficult to manufacture the micro mirrors array which is 14 . Usually, DOE is working with the zoom lens and axicon.…”

Section: Beam Shaping Unitmentioning

confidence: 99%

Detailed illuminator design for full-field ArF lithography system with a method based on the fly's eye

Wei

Liu

2012

SPIE Proceedings

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Lithography is the key technology to semiconductor manufacture. With the rapid improvement of projection lens and resolution enhancement technique (RET), the essence of the illuminator can never be overestimated in the lithography system. However, due to various and complex components and the fact that fewer design methods were proposed in the papers compared with those of the projection lens, a detailed design method for the illuminator is needed. This paper introduces the detailed design process for the illuminator in a NA 0.75 lithography system on 90nm node. The exposure field at the reticle plane is 104mm×42mm. The illuminator mainly consists of three parts: the beam shaping unit, the uniformizer and the relay lens. In order to construct the matching relationship among the various components in the illuminator, a design method based on the fly's eye, which is the core and starting point, has been proposed. This method has been successfully used in small field lithography system. With this method, the matching relationship in the illuminator can be determined easily, and the illumination NA and size are guaranteed simultaneously. Furthermore, the detailed design for some key issues in the illuminator is given: the diffractive optical element (DOE), zoom lens and axicon are used together to generate different sources in the entrance pupil of the projection lens; the condenser design; and 1X relay with two cylinder lenses to achieve trapezoid intensity distribution in the scan direction. A demonstration simulation result is given, and the uniformity of the non-scan and scan direction reached 1.2% and 1.7% respectively under all illumination modes. The result showed good performance and the requirements of the lithography tools have been met.

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“…There are 2 methods to generate a freeform source; one is by means of Diffractive Optical Elements (DOE) and the other is by means of ASML's programmable illumination system named FlexRay TM , where thousands of micro-mirrors can generate a freeform source instantaneously as shown in Fig. 2 5), 6) . It may take several weeks to fabricate a DOE and the number of DOEs that can be stored in a scanner's DOE exchanger is limited.…”

Section: Smo and Full Chip Mask Optimizationmentioning

confidence: 99%

Extension of optical lithography by mask-litho integration with computational lithography

Takigawa¹,

Gronlund²,

Wiley³

2010

SPIE Proceedings

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Wafer lithography process windows can be enlarged by using source mask co-optimization (SMO). Recently, SMO including freeform wafer scanner illumination sources has been developed. Freeform sources are generated by a programmable illumination system using a micro-mirror array or by custom Diffractive Optical Elements (DOE). The combination of freeform sources and complex masks generated by SMO show increased wafer lithography process window and reduced MEEF. Full-chip mask optimization using source optimized by SMO can generate complex masks with small variable feature size sub-resolution assist features (SRAF). These complex masks create challenges for accurate mask pattern writing and low false-defect inspection. The accuracy of the small variable-sized mask SRAF patterns is degraded by short range mask process proximity effects. To address the accuracy needed for these complex masks, we developed a highly accurate mask process correction (MPC) capability. It is also difficult to achieve low false-defect inspections of complex masks with conventional mask defect inspection systems. A printability check system, Mask Lithography Manufacturability Check (M-LMC), is developed and integrated with 199-nm high NA inspection system, NPI. M-LMC successfully identifies printable defects from all of the masses of raw defect images collected during the inspection of a complex mask. Long range mask CD uniformity errors are compensated by scanner dose control. A mask CD uniformity error map obtained by mask metrology system is used as input data to the scanner. Using this method, wafer CD uniformity is improved. As reviewed above, mask-litho integration technology with computational lithography is becoming increasingly important. .

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Generation of arbitrary freeform source shapes using advanced illumination systems in high-NA immersion scanners

Cited by 24 publications

References 16 publications

Robust hybrid source and mask optimization to lithography source blur and flare

Robust hybrid source and mask optimization to lithography source blur and flare

Detailed illuminator design for full-field ArF lithography system with a method based on the fly's eye

Extension of optical lithography by mask-litho integration with computational lithography

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