Development of a new mask pattern inspection tool NPI-7000 and applied results to EUV mask inspection

"Investigation of defect detectability for extreme ultraviolet patterned mask using two types of high-throughput electron-beam inspection systems," J. Abstract. Defect detectability using electron-beam (EB) inspection for an extreme ultraviolet (EUV) mask was investigated by comparing a projection electron microscope (PEM) and a scanning electron microscope (SEM) inspection system. The detectability with EB does not coincide with the printability data because the contrasts of the EUV aerial image and EB image for EUV mask are reversed. The 16-nm-sized defect on a half-pitch 64-nm line and space (L/S) pattern is detected even when the line edge roughness is taken into account in both PEM and SEM inspections by applying a special algorithm for image processing. The required and robust inspection conditions, such as the number of electrons per pixel and pixel size (resolution), were examined for an SEM inspection system. The throughput of the PEM inspection system corresponds to that of the multibeam SEM one with 200 to 1850 beams. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Section: Comparison Of Defect Detectability Betweenmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Investigation of defect detectability for extreme ultraviolet patterned mask using two types of high-throughput electron-beam inspection systems

Iida¹,

Hirano²,

Amano³

et al. 2016

“…Continued shrinkage of pattern size has been leading to difficulties in detecting small defects. 1 Improvement in image resolution is realized by using an electron beam as used in the SEM-type inspection systems, but because of the very small electronbeam spot size used in such systems, it takes too much time for inspection. Therefore, we have been developing a projection electron microscope (PEM) 2,3 for pattern inspection and have evaluated its feasibility.…”

Section: Introductionmentioning

confidence: 99%

Impact of B₄C capping layer for extreme ultraviolet mask on the sensitivity of patterned mask inspection using a projection electron microscope

Iida¹,

Hirano²,

Amano³

et al. 2014

Abstract. The inspection sensitivity of a patterned extreme ultraviolet mask with B 4 C-capped multilayer (ML) was investigated using a simulated projection electron microscope (PEM) image. Extrusion and intrusion defects with 16-nm size were detected with their intensity of >10 times the standard deviation of the background level on a half-pitch 64-nm line-and-space pattern. The defect detection sensitivity in this case was higher than that of a Ru-capped ML sample and has a potential to meet the requirement for beyond 16-nm node generation from the standpoint of patterned mask inspection using the PEM technique. These results indicate that the B 4 C capping layer, besides its good durability, has an advantage for high sensitivity of patterned mask inspection. The optimal condition of the incident beam energy was found to be 500 and 1,000 eV for the samples of B 4 C-capped ML and B 4 C-buffered Ru-capped ML, respectively. The sensitivity of defect detection was strongly affected by the difference of secondary electron emission coefficients (SEECs) between the absorber layer and capping layer. However, the small incident beam energy was found to be preferable when the SEEC difference was relatively high. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

“…For example, the lack of sufficient light-source power, particle-free mask handling, defect-free and flat mask blanks, [1][2][3][4][5] and resist material development 6,7 need to be resolved. From the viewpoint of EUV mask fabrication, mask pattern defect inspection [8][9][10] and repair [11][12][13] are some of the most demanding tasks to be addressed. The reason is that for the EUVL generation, the device pattern feature size happens to be exceedingly small and calls for a higher repairing accuracy than would be required in optical lithography.…”

Section: Introductionmentioning

confidence: 99%

Phase defect detection signal analysis: dependence of defect size variation

Amano¹,

Watanabe²,

Abe

2015

Abstract. The influence of the size or volume of the phase defect embedded in the extreme ultraviolet mask on wafer printability by scanning probe microscope (SPM) is well studied. However, only a few experimental results on the measurement accuracy of the phase defect size have been reported. Therefore, in this study, the measurement repeatability of the phase defect volume using SPM and the influence of the defect volume distribution on defect detection signal intensity (DSI) using an at-wavelength dark-field defect inspection tool were examined. A programmed phase defect mask was prepared, and a defect size measurement repeatability test was conducted using an SPM. As a result, the variation of the measured volume due to the measurement repeatability was much smaller than that of the defect-to-defect variation. This result indicates that measuring the volume of each phase defect is necessary in order to evaluate the defect detection yield using a phase defect inspection tool and wafer printability. In addition, the images of phase defects were captured using an at-wavelength dark-field inspection tool from which the defect DSIs were calculated. The DSI showed a direct correlation with the defect volume. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.