Mask inspection

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

Wafer fab mask qualification techniques and limitations

Abstract: Mask inspection and qualification is a must for wafer fabs to ensure and guarantee high and stable yields. Single defect events can easily cause a million dollar loss through a defect duplicating onto the wafer. Several techniques and methods for mask qualification within a wafer fab are known but not all of them are neither used nor understood regarding their limitations. Increasing effort on existing tool platforms is necessary to detect the defects of interest which are at the limit of the tools specification - On the other hand next generation tools are very sensitive and therefore consume only a negligible amount of time for recipe optimization. Knowing the limits of each inspection tool helps to balance between effort and benefit. Masks with programmed defects of 90nm and 65nm design rule were used in order to compare the different available inspection techniques. During the course of this technical work, the authors concentrate mainly on two inspection techniques. The first one inspects the reticle itself using KLA-Tencor's SLF27 (TeraStar) and SL536 (TeraScan) tools. As the reticle gets inspected itself this is the so called "direct" mask defect inspection. The second inspection technique discussed is the "indirect" mask defect inspection which consists of printing the pattern on a blank wafer and use KLA-Tencor's bright-field wafer inspection tool (2xxx series) to inspect the wafer. Data of this work will include description of the techniques, inspection results, defect maps, sensitivity analysis, effort estimation as well as limitations for both techniques for the used design rule.

Photomask formation method, photomask, and semiconductor device fabrication method

Abstract: According to an aspect of the invention, there is provided a photomask formation method including forming, on a photomask, a pattern obtained by coding information including inspection information for inspecting the photomask and an information attribute which identifies a type of the inspection information; reading the inspection information from the pattern; and inspecting the photomask on the basis of the read inspection information.

Meeting the challenge of advanced lithography reticle inspection

Abstract: New inspection capabilities have been developed in order to meet the emerging needs of reticle inspection. Many proposed optical proximity correction (OPC) methods currently utilize small (< 0.5 micrometers ) edge jogs on the reticle to affect edge feature placement on the wafer. A test plate with 50 nm to 0.50 micrometers edge jogs was fabricated and characterized with automatic inspection equipment. Maintaining input database resolution was found to be a significant factor in eliminating false stops at a high defect detection sensitivity. Inspection of attenuated and embedded attenuated (single layer halftone) phase shifting masks (PSM) has been successfully accomplished for both non-patterned blanks and patterned reticles. A new inspection mode was developed for non-patterned attenuated blank inspection which demonstrated 0.3 micrometers pinhole detection sensitivity and has the capability for +/- 5% absolute transmission error detection. Using programmed defect embedded attenuated phase shift mask test plates, defect detection sensitivity was found to be very similar to that of chrome masks. Deep UV (DUV) stepper technology for the production of 0.25 micrometers linewidths will challenge maskmakers' lithography, inspection, and repair processes.

Programmable photolithographic mask based on nano-sized semiconductor particles

Abstract: Semiconductor nano-particles, due to their specific physical properties, can be used as optical modulator and reversible photo-bleachable materials for a wide spectrum, from far infrared to deep U.V. In this patent, nano-particles are provided with control circuitry to form a programmable mask. The optical characteristics of the nano-particles change to provide patterned light. Such patterned light can be used for example to expose a photoresist on a semiconductor wafer for photolithography. Other applications include, reversible contrast enhancement layer (R-CEL) in optical lithography, lithography mask inspection and writing and optical storage technologies.

Mask inspection device

Abstract: PURPOSE: To inspect a mask used for the exposure treatment of a short wavelength. CONSTITUTION: Excimer laser beams with the same short wavelength as that of exposure light are applied to a mask 20 by a lighting optical system for inspection which is set to the same numerical aperture as the lighting optical system of an exposure device and pattern light through the mask 20 is projected by an observation optical system for inspection set to the same number of openings as the projection system of the exposure device for observing the image, thus applying light with a short wavelength, for example excimer laser beams with the wavelength of DUV (248-nm) and VUV (193nm), to the mask 20 and inspecting the fine mask 20.