Mask inspection

About: Mask inspection is a research topic. Over the lifetime, 1072 publications have been published within this topic receiving 8696 citations.

Patterned mask inspection technology with Projection Electron Microscope (PEM) technique for 11 nm half-pitch (hp) generation EUV masks

Abstract: High-sensitivity EUV mask pattern defect detection is one of the major issues in order to realize the device fabrication by using the EUV lithography. We have already designed a novel Projection Electron Microscope (PEM) optics that has been integrated into a new inspection system named EBEYE-V30 (“Model EBEYE” is an EBARA’s model code), and which seems to be quite promising for 16 nm hp generation EUVL Patterned mask Inspection (PI). Defect inspection sensitivity was evaluated by capturing an electron image generated at the mask by focusing onto an image sensor. The progress of the novel PEM optics performance is not only about making an image sensor with higher resolution but also about doing a better image processing to enhance the defect signal. In this paper, we describe the experimental results of EUV patterned mask inspection using the above-mentioned system. The performance of the system is measured in terms of defect detectability for 11 nm hp generation EUV mask. To improve the inspection throughput for 11 nm hp generation defect detection, it would require a data processing rate of greater than 1.5 Giga- Pixel-Per-Second (GPPS) that would realize less than eight hours of inspection time including the step-and-scan motion associated with the process. The aims of the development program are to attain a higher throughput, and enhance the defect detection sensitivity by using an adequate pixel size with sophisticated image processing resulting in a higher processing rate.

Illumination system and projection objective of a mask inspection apparatus

Abstract: The invention concerns an illumination system and a projection objective of a mask inspection apparatus. In accordance with an aspect of the invention an illumination system (610) in operation of the mask inspection apparatus illuminates a mask (630) with an illumination bundle of rays (615) having a centroid ray, wherein said centroid ray has a direction dependent on the location of the incidence of the illumination bundle of rays (615) on the mask (630).

Inspectability and Lithographic Effects of Reticle Defects Under Aggressive OPC Environment

Abstract: Today, many IC manufacturers use OPC (Optical Proximity effect Correction) technique to obtain finer circuit geometries by adding serifs and jogs to conventional binary mask. Moreover, for endless device shrink in the absent of alternative lithography solution, successful below-half-wavelength lithography requires “much stronger OPC” which consisted of complicate patterns generated from the finer grid size of OPC software or many assist patterns to the main patterns. The mask industry, therefore, is now facing significant problems induced by both increasing write time and defect-like-small complicated OPC patterns. It is questionable that current inspection system could detect all the defect-sources as the aggressiveness of OPC is accelerated. It is not everything to detect small defect only. The direction of development of new reticle inspection tool should be directed by a smart strategy under such an aggressive environment. This paper details the lithographic effects under the 193nm wavelength and inspection sensitivity using newly developed DUV inspection system for various defects on OPC reticle. The relationship between lithographic effects and reticle inspection sensitivity was investigated according to the defect type, defect size, defect position and the aggressiveness of OPC. From this study the requirements of next generation inspection system would be clarified to necessitate good OPC mask manufacturing.

Photoemission monitoring of euv mirror and mask surface contamination in actinic euv systems

Abstract: Photoelectron emission mapping systems for use with EUV (extreme ultraviolet) mask inspection and lithography systems are described. The mapping systems may be used to provide photoelectron emission maps for EUV photolithography masks and/or EUV mirrors. The systems use EUV photoelectron sources used for mask inspection or photolithography to impinge EUV light on the masks and/or mirrors. The EUV light generates photoelectron on the surfaces of the mask and/or mirrors and the photoelectrons are collected and analyzed by detectors placed away from optical spaces of the EUV chamber.

Advanced Mask Inspection and Metrology

Abstract: Lithography is one of the most important semiconductor micro‐fabrication technologies that form mask pattern images onto the substrate. Since a mask is the original edition of semiconductor patterns, precise control of the mask aperture size becomes critical. The masks have to be made up in the accurately controlled patterns and zero defects. Therefore, mask inspection and metrology that guarantee the mask qualities are important key technologies for realizing the semiconductor production with high reliability and high yield. The advanced inspection and metrology are being developed. The requirements, technical issues, and current status of these technologies are reported. Mask inspection technologies for next generation lithography such as electron projection lithography (EPL) and extreme ultraviolet lithography (EUVL) are also reported.