Image analysis – Applications – Manufacturing or product inspection
Reexamination Certificate
1999-01-06
2003-09-02
Werner, Brian (Department: 2621)
Image analysis
Applications
Manufacturing or product inspection
C382S144000, C382S148000, C382S151000
Reexamination Certificate
active
06614923
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pattern inspecting method and an apparatus thereof, and a pattern inspecting method on a basis of an electron beam pictures or images and an apparatus thereof, with which a picture, displaying physical properties of an object such as a semiconductor wafer, TFT, a photo mask and so on, is obtained by use of an electron beam, a light or the like, and the obtained picture is compared with a picture which is obtained separately therefrom, thereby detecting defects or quasi-defects (or defective candidates), in particular the fine or minute ones thereof.
In a conventional art
1
, as is described in Japanese Patent Laying-Open No. Sho 57-196377 (1982), there is already know a testing or an inspection, wherein a pattern including a repetitive pattern, being formed on an object to be tested or inspected such as a semiconductor wafer, is detected to be memorized, and the detected pattern is fitted or aligned with to a pattern which is memorized one time before, in an accuracy of degree of each pixel, thereby extracting a discrepancy or difference between the two patterns fitted or aligned with in the positions thereof so as to recognize or acknowledge the defects therein. Further, in a conventional art
2
, as is disclosed in Japanese Patent Laying-Open No. Hei 3-177040 (1991), there is also known a technology, wherein a portion due to distortion or deformation in the detection points or positions between two pictures is improved among the problems of discrepancies or differences between the both images in normal portions thereof. Namely, in the conventional art
2
, there is described the technology, wherein an object pattern is detected as a picture signal, and the detected pattern is aligned, or adjusted in the position by an unit of pixel with that which is memorized in advance or that which is detected separately. The two of them, which are aligned in positions by the unit of pixel (pixel unit), are further aligned in positions at a degree being finer or lower than the pixel (i.e., sub-pixel unit), so as to be compared and extracted errors therefrom in the image signals of those two patterns which are aligned in positions at the degree finer than the pixel, thereby recognizing or acknowledging the defect(s) of the pattern(s).
Between the two pictures to be compared, there exist the minute difference in the pattern shape, the differences in the values of gradation, distortion or deformation in the patterns, misalignment in positions and so on, even in a normal portion, due to a detection object sample itself and an image detection system thereof. Namely, as the discrepancies or inconsistency in the normal portion, there are some which are caused by the object itself and other(s) which are caused by a side of the testing or inspecting apparatus thereof.
The discrepancy or inconsistency caused by the test object is mainly due to a delicate difference caused through a wafer fabricating processes, such as etching and so on. This is because it looks to be the minute difference in shapes, or as the gray level difference between the repetitive patterns on the detected images.
The discrepancies, which are caused at the testing or inspecting apparatus side, include quantizing errors due to vibration of stages, various electric noises, mis- or mal- focusing and sampling, fluctuation in illumination light amount especially in a case of an optical system, fluctuation in electron beam current especially in a case of an electron beam system, and gaps or shifts in scanning position of the electron beam due to electrical charge of the sample and/or of an electronic-optical system, etc. In particular, in the electron beam system, influences due to geometric distortion is remarkable in the periphery portion of the test object. Those appear in the forms of differences in the gradation values of the portion of the image, the geometric distortion, and the gaps or shifts in the position.
In the conventional art
1
mentioned above, there are problems that, since the discrepancies occur even in the normal portion due to the causes of factors listed in the above, erroneous report occurs very often if each of those discrepancies is decided to be the defect restrictively or minutely, one by one. While, if a reference or criteria to decide the defect is loosen or lowered for preventing from the above, it is impossible to detect the minute or fine defect correctly.
Further, with the conventional art
2
mentioned above, though an only effect can be obtained in reducing or lowering the influence due to the misalignment in the positions between the pictures or images, among those influences due to the minute difference in the pattern shape, the differences in the gradation values, the distortion or deformation of the patterns, and the gaps or shifts in positions and so on, which are caused by the test object itself and the image detecting system thereof, but it is still not sufficient, nor takes the other problems into considerations thereof any more.
2. Summary of the Invention
An object is, according to the present invention for dissolving the problems of the conventional arts mentioned above, to provide a pattern testing method and an apparatus therefor, which can further reduce or lower the possibility of occurring the erroneous reports which are caused by the discrepancies or differences due to the sample itself and the image detecting system thereof, so as to enable the detection of the more minute or the finer defects.
Further, an another object of the present invention is to provide a pattern testing or inspecting method on a basis of electron beam picture or image and an apparatus thereof, which can further reduce or lower the possibility of occurring the erroneous reports which are caused by the discrepancies due to the sample and the image detecting system, on a basis of the electron beam picture of the test object itself, so as to enable the detection of the more minute or the finer defects.
Further, other object of the present invention is to provide a pattern testing method on a basis of electron beam picture or image and an apparatus thereof, which can further reduce or lower the possibility of occurring the erroneous reports which are caused by non-uniform distortion or deformation on the detected images due to the sample and the image detecting system thereof, on a basis of the electron beam picture of the sample, so as to enable the detection of the more minute or the finer defects.
Further, other object of the present invention is to provide a method and an apparatus therefor, having stable gradation values being suitable for testing, and being able to obtain an electron beam picture or image with less geographic distortion, in the pattern inspecting with use of the electron beam image of the sample.
Moreover, further other object of the present invention is to provide a method and an apparatus therefor, enabling the inspecting all over surface including a central portion and a peripheral portion as well, of the sample in the pattern inspecting with use of the electron beam image of the sample.
For dissolving the above objects, according to the present invention, there are provided a pattern inspecting method and an apparatus thereof and a pattern inspecting method on a basis of an electron beam image and an apparatus thereof, wherein inspection is made upon defect or defective candidate on a sample on the basis of a first data which are arranged in two-dimension, by making sampling values in physical quantity from a certain area selected on the sample as gradation values, and a second image data containing contents which can be a comparison sample for the first image data, and each of which has the following features.
Namely, according to the present invention, there are provided an image dividing and cutting-out step or means thereof, for memorizing said first image data and second image data sequentially for a predetermined area, and for dividing and cutting out each of those first and second data me
Doi Hideaki
Hiroi Takashi
Maeda Shuji
Ninomiya Takanori
Shishido Chie
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Werner Brian
LandOfFree
Pattern inspecting method and apparatus thereof, and pattern... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pattern inspecting method and apparatus thereof, and pattern..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pattern inspecting method and apparatus thereof, and pattern... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3093900