Mask inspection

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

Defect management of EUV mask

Abstract: Extreme Ultraviolet Lithography (EUVL) is a promising technology for the fabrication of ULSI devices with 20nm half-pitch node. One of the key challenges before EUVL is to achieve defect-free masks. There are three main categories of mask defects: multilayer defects which cause phase defects, absorber pattern defects, and particles during blank/mask fabrication or mask handling after mask fabrication. It is important to manage multilayer defect because small multilayer defects are difficult to be identified by SEM/AFM after mask patterning and can impact wafer printing. In this paper, we assess blank defect position error detected by 3 rd generation blank inspection tool, using blank defect information from blank supplier and 199nm wavelength patterned mask inspection tool NPI-7000. And we rank blank defect in the order of projection defect size to multilayer in order to estimate blank defect printability. This method avoids overestimating the number of potential killer defects that hardly be identified by SEM/AFM under the condition that EUV-AIMS is not available.

Pattern shape analysis tool for defect judgement of photomask

Abstract: It has been used to measure the maximum length of defect size for the defect decision method at the reticle inspection review. But since 0.25-0.18 micrometers node, we need to have another method to measure and judge the defect because of the complicated pattern line OPC shape and defects which could not decide to be acceptable or not for sensitive defect printability. The best way to know the effect of defects is to print on wafer or to use special review tool so called optical lithography simulation microscope like AIMS in order to judge these defects. But AIMS requires optical parameter of the wafer exposure machine. And its operation takes much time. And most of the detected defects can be judged at the photomask inspection process. We propose new judgement method for defect review precisely and easily. We have developed pattern shape analysis tool that makes defect shape of inspection review image some contact hole pattern example measured by its area and intensity values or another image acquisition system like SEM some quantitative expression. This method is useful for measuring the defect on a complicated pattern like OPC, corner rounding or edge roughness as pattern quality, or area size of a contact hole. Moreover, this method does not remain at the measurement with 2D pattern and can take the total quality of the light as the flux as well. We measured the shape of the mask pattern and the defect quantitatively using this method and evaluated print possibility about the defect print step.

Method of inspecting mask defect and method of manufacturing semiconductor device

Abstract: PROBLEM TO BE SOLVED: To provide a manufacturing technology of a semiconductor device using a defective modification technology of a reflective mask which lets extreme ultraviolet (EUV) light having the wavelength of near 13.5 nm be an exposure light source. SOLUTION: When transferring a mask pattern to a photoresist film applied on a wafer principal surface, after transferring on an off-condition of under dose or defocus or both, a defective inspection is carried out through a process which inspects a transferred pattern to the photoresist film with a scanning electron microscope (SEM) for a voltage potential controlling type visual inspection. Thereby, the visual inspection of a multiple layers phase defect becomes possible by an easy and practical through-put in a hole pattern which cannot be inspected easily by a mask inspection, and the yield is improved by supplying a defect free mask which is performed with a defective relief according to classification of the cause of failure. COPYRIGHT: (C)2010,JPO&INPIT

Optical compensation in high numerical aperture photomask inspection systems for inspecting photomasks through thick pellicles

Abstract: An objective lens system having reconfigurable optical components that enable the inspection of inspection surfaces in the absence of a pellicle or through a thin membrane pellicle, and using the same system, also enabling the inspection of inspection surfaces through a thick pellicle. An objective lens system includes a first group and a second group of optical elements. The first group of optical elements enables high numerical aperture and beam contraction. The second group of optical elements is capable of two mode operation enabling, in one mode, inspection through a thin membrane pellicle or in the absence of a pellicle and in another mode, enabling inspection through a thick pellicle. The system can also be enhanced through the use of an interposable aberration corrector plate that is used to correct optical aberrations caused by the presence, absence, or thickness of pellicles.

Detection of thin line for selective sensitivity during reticle inspection

Abstract: Methods and apparatus relating to the inspection of photomasks are described. In an embodiment, detection of thin line or sub-resolution assist features may be used for selective sensitivity during photomask inspection. Other embodiments are also described.