White River Junction, VT, United States
White River Junction, VT, United States

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Davydova N.,ASML Netherlands B.V. | De Kruif R.,ASML Netherlands B.V. | Rolff H.,AMTC GmbH and Co. KG | Connolly B.,Toppan Photomasks Inc. | And 5 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

EUV lithography performance is improved significantly by optimizing and fine-tuning of the EUV mask. The EUV mask is an active element of the scanner optical system influencing main lithographic figure of merits such as image contrast, critical dimension uniformity (CDU), focus and overlay. The mask stack consists of Mo/Si multilayer acting as a bright field and a patterned absorber stack. In this work we will concentrate on investigation of EUV absorber. Absorber topography that is pronounced compared to the imaging wavelength of 13.5 nm, will give rise to various mask 3d effects such as shadowing or dependence of CD on feature orientation, best focus shift of different resolution structures, etc.[1][2]. Light interference in the absorber layer results in swinging behavior of various lithography metrics as function of the absorber height[5]. Optimization of the mask absorber allows mitigating mask 3d effects and improving imaging performance. In particular, reduction of the absorber height mitigates the shadowing effect and relaxes requirements on Optical Proximity Correction (OPC), but can result in smaller Process Window due to lower imaging contrast and larger best focus shifts. In this work we will show results of an experimental approach to absorber height optimization. A special mask with 27 different absorber heights in the range 40-70 nm is manufactured by Toppan Photomasks. EUV reflectivity spectra are measured for the different absorber heights and an experimental swing curve is constructed. For each absorber height various resolution features are present on the mask. Lines of 27 nm and 22 nm are imaged on the wafer using the ASML EUV scanner NXE:3300B with an NA of 0.33. The experimental CD swing curve is constructed as well as HV change as a function of absorber height. The impact of the absorber height on Exposure Latitude (EL) and Dose to Size (D2S) is investigated. EL improves with increasing absorber height in some cases, however there is no clear EL gain for a 70 nm absorber compared to for example 52 nm absorber. D2S does show a clear trend through absorber height. In particular, D2S can be reduced by absorber height reduction: e.g. for 52 nm absorber D2S is 5% or 1 mJ/cm2 smaller compared to 70 nm. The experimental results are used for calibration and verification of rigorous mask 3d simulations. This knowledge is crucial for accurate OPC of production masks and allows for accurate litho simulations of EUV user cases as a basis for lithography roadmaps towards High Volume Manufacturing and High NA EUV. © 2013 SPIE.


Negishi Y.,TOPPAN PHOTOMASKS INC. | Fujita Y.,TOPPAN PHOTOMASKS INC. | Seki K.,TOPPAN PHOTOMASKS INC. | Konishi T.,TOPPAN PHOTOMASKS INC. | And 6 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

Extreme Ultraviolet Lithography (EUVL) is the leading candidate for next generation lithography. EUVL has good resolution because of the shorter wavelength (13.5nm). EUVL also requires a new and complicating mask structure. The blank complexity and substrate polishing requirements result in defects that are difficult to eliminate or repair. Due to these challenges, shifting the pattern so that absorber covers the multilayer defects is one option for mitigating the multilayer defect problem. We investigated the capability and effectiveness of pattern shifting using authentic layouts. The rough indication of, "how many of what size defects are allowable", is shown in this paper based on the margin for the 11nm HP pattern. Only the twenty 300nm-sized defects are allowable for current location accuracy of the blank inspection and writing tools. On the other hand, sixty70nm-sized defects are allowable for the improved location inaccuracy. Furthermore we exercised the full process for pattern shift using a leading-edge 50 keV e-beam writer to confirm feasibility and it was successfully performed. © 2013 SPIE.


Lawliss M.,IBM | Gallagher E.,IBM | Hibbs M.,IBM | Seki K.,Toppan Photomasks Inc. | And 3 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

Mask defectivity is a serious problem for all lithographic masks, but especially for EUV masks. Defects in the EUV blank are particularly challenging because their elimination is beyond control of the mask fab. If defects have been identified on a mask blank, patterns can be shifted to place as many blank defects as possible in regions where printing impact will be eliminated or become unimportant. For those defects that cannot be mitigated through pattern shift, repair strategies must be developed. Repairing defects that occur naturally in the EUV blank is challenging because the printability of these defects varies widely. This paper describes some types of native defects commonly found and begins to outline a triage strategy for defects that are identified on the blank. Sample defects best suited to nanomachining repair are treated in detail: repairs are attempted, characterized using mask metrology and then tested for printability. Based on the initial results, the viability of repairing EUV blank native defects is discussed. © 2014 SPIE.


Seki K.,Toppan Photomasks Inc | Badger K.,IBM | Gallagher E.,IBM | Konishi T.,Toppan Photomasks Inc | McIntyre G.,IBM
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

EUV defect detectability is evaluated both through simulation and by conventional mask inspection tools at various wavelengths (13.5, 193, 257, 365, 488 and 532 nm). The simulations reveal that longer wavelength light penetrates deeper into the multilayer than shorter wavelength light, however this additional penetration does not necessarily provide an advantage over shorter wavelengths for detecting defects. Interestingly, for both blank and patterned mask inspections, each wavelength detected unique defects not seen at other wavelengths. In addition, it was confirmed that some of the defects that are detected only by longer wavelengths are printable. This study suggests that a combination of wavelengths may be the most comprehensive approach to finding printable defects as long as actinic inspection is not available. © 2012 SPIE.


Badger K.D.,IBM | Seki K.,Toppan Photomasks Inc.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

As part of 20 nm/22 nm process development, an evaluation was performed to determined the impact of Thin OMOG on mask inspection. Despite significant improvements in mask inspectability and reduced database modeling errors, thin OMOG demonstrated lower defect sensitivity as compared to Standard OMOG at the same inspection conditions (calibration, sensitivity). Stack height aside, the primary difference between standard and thin OMOG is attenuator reflectivity. It is surmised that the reduction in sensitivity is due to a lower reflected light contrast on thin-OMOG. This characteristic was noted for both 257 nm and 193 nm inspection wavelengths. In addition to the reduction in defect sensitivity, an unexpected phase interference was noted at the image edge with a 193 nm inspection wavelength, for Standard OMOG, but not for Thin OMOG. This interference, or undershoot is due in part to the low difference in reflectivity and phase between the quartz and the attenuator on the Standard OMOG substrate. This difference is more than five times greater for the Thin OMOG attenuator. The primary focus of this paper is on the characterization of thin OMOG relative to the interaction between attenuator reflectivity, image quality, database modeling and tool calibrations as they relate to mask inspectability and defect sensitivity. This paper will also address the changes required to compensate for the loss of sensitivity induced by the introduction of the thin OMOG absorber. © 2011 SPIE.


Gallagher E.,IBM | Wagner A.,IBM | Lawliss M.,IBM | McIntyre G.,IBM | And 3 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

Defects in the EUV mask blank are one of the largest hurdles to achieving manufacturing readiness of EUV masks. For defect-free masks, the obvious approach is to order blanks that do not have defects or to shift the pattern so that remaining defects do not create a printed defect on wafer. The approach during development should be different. At this learning phase, it is wise to study the defects as they occur naturally on the EUV mask blank. This paper outlines a comprehensive approach to building a mask specifically to showcase the native defects so that they can be studied and repairs can be attempted. The method applied to mask build, defect inspection and characterization will be reviewed in detail. Printability of the mask defects of interest are characterized using both wafer printing and EUV microscope data. Repairs are attempted and characterized. In the end, the impact of native defects is discussed along with the viability of various repair methods. © 2014 SPIE.


Badger K.,IBM | Gallagher E.,IBM | Seki K.,Toppan Photomasks Inc. | McIntyre G.,IBM | And 3 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

EUV wavelength inspection tools are several years away from product release. Until then, the EUV Lithography (EUVL) community faces the challenge of inspecting EUV masks at non-actinic wavelengths. It is critical to understand how to improve mask inspectability and defect sensitivity. The absorber stack is one contributor, since changing the film stack modifies image contrast. To study the effect, masks were fabricated from three different film stacks on which the thickness of the low reflective and absorber layers vary. These three absorbers are identified in this paper as Type A, Type B and Type C. All blanks had the same Ru-capped multi-layer substrate beneath the absorber stack. Inspection contrast, defect sensitivity and inspectability were measured on a 193nm wavelength inspection tool. The focus of this paper will be on inspection at the 193nm wavelength; however, simulated wafer results at the 13.5 nm EUV exposure wavelength will be included to anchor the relevance of the mask inspection results. A comparison of the different absorber stacks, the ability to detect defects on the various masks, and how defects on these substrates prints on wafer will be provided. This work addresses the gap between EUVL mask inspection and wafer defect printability and how the two views differ relative to various absorber stacks. © 2013 SPIE.


Isogawa T.,Toppan Photomasks Inc. | Seki K.,Toppan Photomasks Inc. | Lawliss M.,GLOBALFOUDRIES | Qi Z.J.,GLOBALFOUDRIES | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

A variety of repairs on EUV multilayer were conducted including protection against pattern degradation in manufactural use in order to evaluate feasibility of multilayer repair and the protection schemes. The efficacy of post-repair protection techniques are evaluated to determine the lifetime of multilayer repairs. Simulations were used to select the optimal material thicknesses for repair protection, and the simulation results are verified with the lithographic results. The results showed a high correlation coefficient. Finally, all repaired sites were cleaned multiple times to quantify repair durability and impact on wafer CD. Aerial imaging of the repair sites before and after cleans shows a dramatic degradation of wafer CD post-cleaning. However, we show that applying a surface protection material after multilayer repair successfully mitigates the influence of multilayer degradation during extensive manufacturing operations. © 2015 SPIE.


Kalk F.,Toppan Photomasks Inc.
Semiconductor International | Year: 2010

The litho cell cost per circuit function has decreased by a factor of 3000, even while lithography exposure tool unit prices have increased 24 times. The business model for mask manufacturing and associated infrastructure is distinct and different than the business model for the rest of the litho cell. Designs are increasingly complicated and their costs are rising because design automation is not keeping pace with the products' function requirements. The cost of technology migration favors high-volume manufacturing, yet few chips are produced in high volume. Mask costs are especially affected by the technology migration to EUV. The change in the semiconductor business model presents several opportunities to reduce mask cost, but often at the expense of wafer scanner throughput. Lithography cell efficiency is the key enabler of continuing cost reduction in semiconductor manufacturing.


Patent
Toppan Photomasks Inc. | Date: 2011-09-23

An apparatus for transporting equipment and a method for the manufacture of the apparatus are disclosed. A damping assembly configured to dampen movement of a first item relative to a second item may include an arm and a shock absorber. The arm may be configured to be located between the first item and the second item and may be configured to pivotally couple to the first item and configured to slidably couple to the second item. The shock absorber may be configured to couple between the first item and the arm, such that the shock absorber dampens rotation of the arm to dampen movement of the first item relative to the second item.

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