Showing papers on "Mask inspection published in 1995"
Patent•
13 Jul 1995
TL;DR: In this paper, an illumination system for generating a light beam, passing that light beam through a fixed optical path and making it almost practically perpendicularly incident to the upper surface of an inspection substrate, transmitted light detector 34 for collecting and detecting the transmitted beams by adjusting them so as to be coaxial to that optical path, reflected light detector 36 for similarly collecting and detected reflected light, comparator for providing a compare value by mutually comparing respective electric signals, and processor for separately providing the expected value of that compare value and discriminating the coincidence between the comparison value and that expected value.
Abstract: PROBLEM TO BE SOLVED: To provide a device and a method for inspecting a substrate in order to automatically perform defect search and type classification at low cost with a little error, especially, to provide a substrate inspecting device and an automatic inspecting method for performing automatic inspection for searching and discovering defective particles and defective graphics different from the intension of a designer on the substrate of mask rectile, etc., and the automatic classification of types of these defects. SOLUTION: This device is composed of an illumination system for generating a light beam, passing that light beam through a fixed optical path and making it almost practically perpendicularly incident to the upper surface of an inspection substrate, transmitted light detector 34 for collecting and detecting the transmitted beams by adjusting them so as to be coaxial to that optical path, reflected light detector 36 for similarly collecting and detecting reflected light, comparator for providing a compare value by mutually comparing respective electric signals, and processor for separately providing the expected value of that compare value and discriminating the coincidence between the compare value and that expected value.
19 citations
Patent•
28 Jul 1995
TL;DR: In this paper, a mask inspection equipment consisting of a first illuminator 2 for projecting the light vertically onto the surface of a mask, a second illuminators 3 for projecting light to the rear surface of the mask, and an optical sensor 6 for observing the mask 1, is presented.
Abstract: PURPOSE:To provide a mask inspection equipment in which the detection sensitivity can be equalized for a transparent defect and opaque defect. CONSTITUTION:The mask inspection equipment comprises a first illuminator 2 for projecting the light vertically onto the surface of a mask 1, a second illuminator 3 for projecting the light to the rear surface of the mask 1, an optical sensor 6 for observing the surface of the mask 1, means 5, 7, 15, 9, and 10 for attaining first or second image information from the output of the optical sensor 6, respectively, when only the first or second illuminator is operated, and means 11 for obtaining third image information by subjecting the first image information to correction of optical reflectance at the opaque part 17 of the mask 1. The mask inspection equipment further comprises means 12 for producing a fourth image signal by correcting the optical transmittance at the transparent part 16 of the mask 1 for the second image information, and means 13, 14 for producing the differential image information between the third and fourth image information.
5 citations
06 Oct 1995
TL;DR: In this article, the authors describe the use of the KLA STARlightTM 300 inspection system for advanced photomask manufacturing and development, which combines state-of-the-art defect detectivity and high speed helps to streamline final mask inspection and improve product quality.
Abstract: This paper describes the use of the KLA STARlightTM 300 inspection system for advanced photomask manufacturing and development. STARlight's combination of state-of- the-art defect detectivity and high speed helps to streamline final mask inspection and improve product quality. For advanced development, previously undetected defects can now be identified, their effects on printability can be quantified, and strategies to eliminate them can be implemented.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
3 citations
19 May 1995
TL;DR: In this paper, a Ta absorber x-ray mask fabrication process was developed that virtually eliminates mask defects by polishing the surfaces of the SiN films to make them as smooth as possible.
Abstract: A Ta absorber x-ray mask fabrication process has been developed that virtually eliminates mask defects. Since most mask defects originate in 2 micrometers thick SiN deposits, the surfaces of the deposited SiN films are polished to make them as smooth as possible. To eliminate the contamination that occurs in fabrication processes, such as back-etching of the substrate, a wet-cleaning technique is employed that uses a strong acid like H2SO4 + H2O2. By using these polishing and cleaning techniques, the defect density can be reduced to less that 5 defects/cm2. To carry out x-ray mask inspection by an electron-beam x-ray mask inspection system, die-to-die comparison of printed resist patterns is introduced. A focused ion beam x-ray mask repair system is used to repair mask defects. Clear repairs are made with Ta deposited on a Ta absorber. The repaired Ta absorber patterns have high chemical durability and are not damaged by strong acid wet- cleaning. This mask fabrication process has led to the production of virtually defect-free x-ray masks with a reasonable yield.
2 citations
06 Oct 1995
TL;DR: A simple, low cost photo mask inspection system based on an IBM compatible PC, both the reference comparison as well as feature extraction approaches have been implemented for guaranteed defect detection.
Abstract: The competitive demand for increased production rates and tighter quality control in manufacturing integrated circuits requires inspection at higher speeds, finer resolution and at various stages during fabrication, all at an affordable cost. Manual inspection is tedious and entails a degree of concentration that is difficult to maintain over long periods of time. This paper presents a simple, low cost photo mask inspection system based on an IBM compatible PC. Both the reference comparison as well as feature extraction approaches have been implemented for guaranteed defect detection. The defects are further analyzed to obtain details regarding the location, dimension, and type of defect. The system also generates a diagnostic report providing detailed information regarding each defect, that has been detected, for use in on line mask repair. The paper describes configuration of the system along with the image processing algorithms used. The paper also discusses the results obtained, the specifications and over all performance of the system.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.