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Showing papers on "Mask inspection published in 1979"


Patent
03 Apr 1979
TL;DR: Optical inspection apparatus for detecting differences between two dies in a photomask and including a carriage for supporting the objects to be inspected and for simultaneously moving such objects along an inspection path, an illuminator for illuminating corresponding portions of the objects as they are moved along the inspection path as discussed by the authors.
Abstract: Optical inspection apparatus for detecting differences between two dies in a photomask and including a carriage for supporting the objects to be inspected and for simultaneously moving such objects along an inspection path, an illuminator for illuminating corresponding portions of the objects as they are moved along the inspection path, electro-optical detectors for individually inspecting the illuminated portions and for developing first and second electrical signals respectively corresponding thereto, electronic memories for storing the first and second electrical signals, a computer for scanning the memories and for electronically aligning a readout of the first signal relative to a readout of the second signal, and a comparator for comparing the electronically aligned signals and for indicating any differences therebetween.

167 citations


Patent
11 Jun 1979
TL;DR: In this paper, a reticle mask is formed by using pattern generator 28 inside generating part 16, but if this mask pattern has insufficiency defect 38 and unneeded-extra defect 39, it is made into bits by generating part 17 to obtain inspected pattern 37.
Abstract: PURPOSE:To accelerate an inspection rate, and to improve the precision of defect inspection by making the comparison between a reference pattern and inspected pattern through hardware, and by attaining the comparison by defect discrimination algorithm. CONSTITUTION:The mask inspection device consists of data converter 15, reference pattern generator 16, inspected pattern generator 17, and defect detection part 18. On the basis of design information, a reticle mask is formed by using pattern generator 28 inside generating part 16, but if this mask pattern has insufficiency defect 38 and unneeded-extra defect 39, it is made into bits by generating part 17 to obtain inspected pattern 37. In conversion part 15, on the other hand, the reference format is generated previously and applied to pattern generator 28, thereby forming reference patter 29 by generating part 17. Then, patterns 29 and 37 are algorithm- discriminated by detection part 18, and the discrimination results are recorded on cassette tape 42.

9 citations


Proceedings ArticleDOI
10 Oct 1979
TL;DR: In this article, a new mask inspection technique based on pattern width measurement is proposed, which can check the fatality of defects, and it does not require the original data for comparison, detects fatal defects, has no special alignment and detects defects as small as 10μm with 100% accuracy.
Abstract: This is a new mask Inspection technique based on pattern width measurement that can check the fatality of defects. Mask quality depends on pattern width and defects in a fatal area where a normal pattern is seriously damage. In this technique, pattern width measurement and fatal defect detection with a laser beam are used for inspection of masks of PC boards. In order to determine the direction of measurement, diffracted laser light at the pattern edge and spatially divided photodetectors are used. The new inspection system (l) measures pattern width, (2)does not require the original data for comparison, (3)detects fatal defects, (4)has no special alignment and (5)detects defects as small as 10μm can be isolated with 100% accuracy.© (1979) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

7 citations


Patent
04 Sep 1979
TL;DR: In this paper, an appearance inspection and a dimension inspection are performed simultaneously in the inspection unit for produced masks. But they do not discuss the effect of these inspections on the precision of the inspection.
Abstract: PURPOSE:To shorten an inspection time and improve an inspection precision by giving a constitution where an appearance inspection and a dimension inspection are performed simultaneously in the inspection unit for produced masks. CONSTITUTION:Produced mask 8 is put on XY stage 9, and photo diode array 14 is moved in the XY direction to scan mask 8. Electric signals VA obtained in this manner are branched to pathes I and II. Signals VA of path I for appearance inspection are converted to binary signals in 15 and are converted to bits in shift register 16. Meanwhile, data selection circuit 17 outputs reference pattern signals V3, and these signals are converted to a pattern in pattern generator circuit 18 and are converted to bits in shift register 19. Comparator 20 compares signals VC and VD with each other and outputs a signal deciding correctness or incorrectness. Signals VA of path II for dimension inspection are triggerred by trigger generator circuit 28, and these signals and output VE of laser length measurement equipment 12 are operated in operation circuit 25. Comparator 26 compares output VF of the operation circuit and signal VG from reference dimension memory circuit 24 with each other and outputs a signal deciding correctness or incorrectness.

5 citations


Patent
01 Sep 1979
TL;DR: In this paper, a photo diode array 14 is out of the scribing line 25a of the mask 1 and the array 16 is on the line 25b, the shift registers 19 and 20 show 1, 0 respectively for the full bits, the difference is operated 21 and the output V1 drives 22 the motor 24 and moves the array 14 upward.
Abstract: PURPOSE:To perform the mask inspection for high accuracy simply, by the alignment of high accuracy without requiring skillful work. CONSTITUTION:When the photo diode array 14 is out of the scribing line 25a of the mask 1 and the array 16 is on the line 25b, the shift registers 19 and 20 show 1, 0 respectively for the full bits, the difference is operated 21, and the output V1 drives 22 the motor 24 and moves the array 14 upward. It stops when the signal of the registers 19 and 20 agrees with each other. Thus, the distance L of array is automatically adjusted. Next, when the array crosses with the scribing line with a slope, the signals obtained from each array are different and since the memory content is correspondingly different, the difference is operated, the motor 8 is driven 10 with the output V2. When the signal of the both registers agrees with each other, the motor stops, causing the array and the scribing line in orthogonal state. After that, the external inspection of mask is made with the condition of the array scanned on the pattern, the signal of the registers 19 and 20 is operated and compared 21 for the propriety, the result is memorized 29 with the output V3, performing the pattern correction.

3 citations