KR20160012319A

KR20160012319A - Method for detecting defect of pattern

Info

Publication number: KR20160012319A
Application number: KR1020140093434A
Authority: KR
Inventors: 황영민; 김상윤; 배정봉; 박희재
Original assignee: 에스엔유 프리시젼 주식회사
Priority date: 2014-07-23
Filing date: 2014-07-23
Publication date: 2016-02-03
Also published as: TWI597492B; KR101661023B1; TW201625934A; CN105301015A; CN105301015B

Abstract

The present invention relates to a defect inspection method of a pattern capable of easily inspecting a defect formed on a substrate by using a master image obtained by photographing the master substrate by an optical system a plurality of times and combining the same, step; A registration step of photographing different regions of the master substrate by using an optical system a plurality of times and registering them as a master image; A photographing step of photographing an inspection area expected to have a defect on a substrate to be inspected at the same magnification as that of the master image through the optical system and registering the inspection area as a test image; And a matching step of matching the master image with the inspection image to search for a defect in the inspection area.

Description

METHOD FOR DETECTING DEFECT OF PATTERN [0002]

The present invention relates to a pattern defect inspection method, and more particularly, to a pattern defect inspection method capable of easily checking the presence or absence of a defect formed in a pattern formed on a large-sized substrate and the position of the defect.

A unit pattern is periodically arranged on the surface of a substrate for a device to form a repeated pattern. Such a unit pattern is originally regularly arranged, but there are cases where a defect is generated unintentionally in a regularly arranged pattern and has a different regularity.

If such defects are generated, such defects are transferred to a pattern to be formed on the substrate for a device, resulting in a problem of causing defects in the substrate for the device. Therefore, it is necessary to check the presence or absence of defects occurring in the repeated pattern in advance.

These defects are almost impossible in terms of time and cost to detect the shape of individual patterns, and it is possible to detect a periodic part among other patterns having periodicity in the whole area, Is determined as a defect.

On the other hand, in recent years, a substrate for a device has a tendency to be large-sized, and it is difficult to perform close inspection on the presence or absence of a defect in the entire area of a pattern arranged on the surface of the large- The approximate position of the pattern estimated as a defect, that is, the pattern having no periodicity is photographed, and an image is photographed for an area including a pattern having no periodicity through a high magnification optical system to determine whether the pattern having no periodicity is defective And then the defect occurrence is determined.

That is, if the pattern of the entire substrate is photographed at a low magnification to check whether there is a pattern having no periodicity, if there is a pattern having no periodicity, the pattern is magnified and photographed through a high magnification optical system to determine whether the pattern having no periodicity is defective .

However, in the above method, only a part of the periodic pattern is photographed at a portion photographed through a high magnification optical system, which causes a problem that the pattern is viewed as a pattern having no periodicity. In addition, The periodicity can not be confirmed in the patterns, so that it can not be confirmed which portion of the entire substrate is photographed through the high magnification optical system.

If such a problem arises, an attempt has been made to solve the above-mentioned problem by shooting the peripheral region of the previously photographed portion again through a high magnification optical system and then combining the photographed image, but there is a further problem that the time required for the defect review process is significantly increased .

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve such conventional problems, and it is an object of the present invention to provide a method and an apparatus for measuring a defective area on a substrate to be inspected, A defect inspection method of a pattern capable of easily inspecting defects formed on a substrate by matching an image.

According to the present invention, the object is achieved by a method of manufacturing a semiconductor device, comprising the steps of: preparing a master substrate free from defects; A registration step of photographing different regions of the master substrate by using an optical system a plurality of times and registering them as a master image; A photographing step of photographing an inspection area expected to have a defect on a substrate to be inspected at the same magnification as that of the master image through the optical system and registering the inspection area as a test image; And a matching step of matching defects in the inspection area by matching the master image with the inspection image.

Here, the registration step and the photographing step are each performed a plurality of times, and the registration step is preferably performed at least once before the photographing step.

It is preferable that the matching step searches for the defect by replacing the area corresponding to the inspection image on the master image with the inspection image.

It is preferable that the optical system has a plurality of magnifications that can be converted, and the registering step registers the master image according to each magnification of the optical system.

And a determining step of determining a position of the defect using at least one of a position of the inspection image on the master image and a position of the defect on the inspection image after the matching step Do.

The method may further include a defect processing step of, when the position of the defect is found through the determination step, processing the defect on the substrate to be inspected.

The determining step sets the position of the defect on the master image to the first coordinate value, designates the position of the inspection image on the master image to set as the second coordinate value, And determining the position of the defect in the inspection image through the displacement between the second coordinate values.

According to the present invention, there is provided a pattern defect inspection method capable of quickly and simply inspecting defects formed on a substrate.

In addition, by registering the master image in advance or in real time, it is possible to minimize the time required to inspect each defect.

Further, when a defect is formed on the substrate, the position of the defect can be accurately grasped.

1 is a flowchart schematically showing a defect inspection method of a substrate according to an embodiment of the present invention,
FIG. 2 is a view schematically showing a master substrate required in the preparation step in the defect inspection method of the substrate according to FIG. 1,
FIG. 3 is a view schematically showing a registering step of registering a master image by taking a master substrate a plurality of times in a defect inspection method of the substrate according to FIG. 1,
FIG. 4 is a view schematically showing a substrate to be inspected in the imaging step in the defect inspection method of the substrate according to FIG. 1,
FIG. 5 is a view schematically showing a test image taken through an imaging step in the defect inspection method of the substrate according to FIG. 1,
6 is a view schematically showing a matching step of matching a check image on a master image in a defect inspection method of a substrate according to FIG. 1,
7 is a view schematically showing a determination step of measuring a defect position in the defect inspection method of the substrate according to FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a pattern defect inspection method (S100) according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart schematically showing a defect inspection method (SlOO) of a substrate according to an embodiment of the present invention.

Referring to FIG. 1, a defect inspection method (S100) of a substrate according to an embodiment of the present invention can quickly and simply check whether or not a defect is formed on the inspection substrate even in a state where a substrate to be inspected is large- A preparing step S110, a registration step S120, a photographing step S130, a matching step S140, a determining step S150, and a defect processing step S160.

FIG. 2 is a view schematically showing a master substrate required in the preparation step in the defect inspection method (S100) of the substrate according to FIG.

Referring to FIG. 1, the preparing step S110 is a step of preparing a master substrate M having no defects. That is, the master substrate M means a substrate on which a pattern to be printed by a user is printed more than the accuracy required by the user.

A pattern 10 including a shape pattern 11 arranged in the lateral direction and a longitudinal direction and a point pattern 12 formed on the top of the shape pattern 11 is formed on the master substrate M in the embodiment of the present invention, . If the shape pattern 11 and the point pattern 12 arranged on the upper side of the shape pattern 11 are regarded as one set, they are repeated every six patterns and have periodicity.

FIG. 3 is a view schematically showing a registration step of photographing a master substrate a plurality of times and registering it as a master image in a defect inspection method (S100) of the substrate according to FIG.

3, in the registering step S120, the different areas of the master substrate M are photographed and combined a plurality of times by using an optical system of the first magnification to form a master image 100 ).

Here, the master image 100 is an image of the master substrate M described above. If the defect is expected to be formed on the substrate S to be inspected in a step to be described later, It becomes a standard to be able to search for the recognition.

In addition, the master image 100 is formed by photographing different areas of the master substrate M a plurality of times and defects thereof. Furthermore, the master image 100 may represent the entire image of the master substrate M and may represent some image of the peripheral region of the region where the defect is expected to form in the master substrate M.

Here, the different regions include not only a case where the respective regions are provided as separate regions but also a case where some regions of the edges are overlapped.

Meanwhile, the optical system used in the embodiment of the present invention may be converted into a plurality of magnifications, and a plurality of master images may be registered by photographing and combining different regions of the master substrate M at respective magnifications .

For example, if the optical system in the embodiment of the present invention can convert to a magnification of 10 magnification, 20 magnification, or 30 magnification, each master image can be registered at 10 magnification, 20 magnification, and 30 magnification.

The optical system for photographing the master substrate M for registering the master image is the same as the apparatus for photographing the inspection image from the substrate to be inspected in the imaging step S130 to be described later, 200) are photographed with images of the same magnification.

In one embodiment of the present invention, the optical system photographs and combines the master substrate M a total of four times to register the master image. That is, the first image 110 on the upper left side, the second image 120 on the upper right side, the third image 130 on the lower left side, and the fourth image 140 on the lower right side are combined, Each boundary contains some overlapping regions.

The master image 100 includes a shape pattern 11 arranged in rows and columns in the same manner as the master substrate M and a dot pattern 12 formed on the top of the shape pattern 11 And their periodicity is the same as that of the pattern on the master substrate, so a detailed description thereof will be omitted here.

The photographing step S130 is a step of photographing an inspection area where a defect is expected to be formed on the inspection target substrate S through an optical system and registering the inspection area as a inspection image.

Here, it is possible to utilize all methods well known in the art to search for an inspection region in which defects are expected to be formed on the substrate S to be inspected.

FIG. 4 is a view schematically showing an imaging step in a defect inspection method (S100) of the substrate according to FIG.

Referring to FIG. 4, in an embodiment of the present invention, an entire image of a substrate S to be inspected is obtained at a lower magnification than an optical system by using an automatic optical inspection (AOI), and defects are formed therefrom It is possible to retrieve the approximate position of the expected inspection area. Of course, it is obvious that the above-described method is not limited by this method as an example in which the inspection area can be searched for the approximate position, Any method capable of estimating a region in which a defect is expected to be formed in the substrate S can be used.

5) obtained through the photographing step S130 has the same shape as that of the inspection area, so that the inspection target substrate S can be inspected, It is an object to determine whether or not there is a defect on the image.

On the other hand, a pattern that deviates from a predetermined periodicity among the patterns photographed on the entire image of the substrate S to be inspected may exist, and this pattern may be estimated as a defect. Here, the inspection region can be defined as a region in which a pattern deviates from a predetermined periodicity, that is, a region including a pattern estimated as a defect. Of course, the defect can be estimated in addition to this method, but it is the same in that the inspection region is a region including the estimated defect.

Here, the inspection image 200 (see Fig. 5) can be photographed such that a point at which a defect is expected to be formed on the substrate S to be inspected is located at the center of the image. That is, the optical system can be photographed after being centered on the basis of a point where a defect is expected to be formed on the substrate S to be inspected.

On the other hand, the inspection image 200 (see Fig. 5) and the master image 100 have the same magnification. This is because the master substrate M and the substrate S to be inspected are photographed using the same optical system in the registration step S120 and the photographing step S130.

Accordingly, it is possible to estimate an area where a defect has been formed through the photographing step (S130), and to examine whether or not a defect actually occurs in an area estimated as a defect-formed area.

5 is a view schematically showing a test image photographed through an imaging step in the defect inspection method of the substrate according to FIG. Here, Fig. 5 (a) schematically shows the case where a defect is photographed in the inspection image, and Fig. 5 (b) schematically shows an image in the case where no defect is photographed in the inspection image.

That is, a shape pattern 211 corresponding to the shape pattern 11 of the master image 100 and a dot pattern 212 corresponding to the point pattern 12 of the master image 100 are displayed on the photographed inspected image 200 , And may further include a defect (D) that does not exist in the master image (100).

Here, the defect (D) present in the inspection image (200) is a pattern or the like formed on the inspection target substrate (S) irrespective of the intention of the user and has a large and small influence on the performance of the inspection target substrate .

The defects D may be formed on the substrate S to be inspected during the manufacturing process of the substrate S to be inspected or the process of printing a pattern on the substrate S to be inspected, It is practically impossible to prevent the occurrence of the substrate S to be inspected. Therefore, a step of inspecting the substrate S to be inspected is performed during the manufacturing process of the substrate S to be inspected or after completion of the manufacturing process of the substrate S to be inspected .

FIG. 6 is a view schematically showing a matching step of matching the inspection image on the master image in the defect inspection method (S100) of the substrate according to FIG.

Referring to FIG. 6, the matching step S140 is a step of checking whether there is a defect in the inspection area of the inspection target substrate S by matching the master image 100 and the inspection image 200. FIG.

In one embodiment of the present invention, the master image 100 and the inspection image 200 are matched to each other by replacing the inspection image 200 with an area corresponding to the inspection area on the master image 100, So that the inspection image 200 can be inserted on the image 100.

Alternatively, an image corresponding to the inspection area may be extracted on the master image 100 and directly compared with the inspection image 200. [

As a result of performing the matching step S140 described above, a defect may or may not be confirmed in the inspection image 200. [ The case where a defect is confirmed in the inspection image 200 is the same as that of FIG. 5 (a) described above, and the case where a defect is not confirmed in the inspection image 200 is as shown in FIG. 5 (b).

Here, in the case where no defect is confirmed in the inspection image 200, for example, as in the embodiment of the present invention, the entire image of the substrate S to be inspected in the imaging step S130 is taken through equipment such as AOI When estimating the approximate position of the defect, it is possible to acquire the entire image of some erroneous substrate S to be inspected due to a reason such as that an erroneous image is photographed according to observation conditions such as reflection of light, .

As described above, when the defect is not searched in the inspection image 200 through the matching step S140, it can be determined that the defect is not substantially defect.

On the other hand, a case where a defect is confirmed in the inspection image 200 will be described later.

FIG. 7 is a view schematically showing a determination step of measuring a defect position in the defect inspection method (S100) of the substrate according to FIG.

Referring to FIG. 7, the determining step S150 is a step of determining a position of a defect when a defect is detected in the inspection image 200 through the matching step S140.

As described above, since the inspection image 200 is photographed such that the point at which the defect is expected to be formed on the substrate S to be inspected is positioned at the center of the inspection image 200, The central portion of the inspection image 200 can be determined as the defect formation position.

Unlike the above, the point where the defect is expected to be formed and the point where the actual defect is formed may be substantially inconsistent. In this case, the defect position on the master image 100 is set to the first coordinate value X1, the position of the inspection image 200 on the master image 100 is set to the second coordinate value X1, The position of the defect in the inspection image 200 can be determined through the displacement of the first coordinate value X1 and the second coordinate value X2.

The second coordinate value X2 may be set to a specific position of the inspection image 200 on the master image 100. For example, the position of the upper left corner of the inspection image 200 on the master image 100 may be Can be set to the coordinate value (X2).

The defect processing step S150 is a step of processing defects on the substrate S to be inspected using the absolute coordinates of the defects obtained through the determining step S140 described above. Here, any method conventionally used can be utilized as a method of processing defects.

The scope of the present invention is not limited to the above-described embodiments, but may be embodied in various forms of embodiments within the scope of the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

100: master image 200: inspection image
S100: Pattern defect inspection method S110: Preparation step
S120: Registration step S130: photographing step
S140: matching step S150: determining step
S160: defect processing step

Claims

Preparing a master substrate having no defects;
A registration step of photographing different regions of the master substrate by using an optical system a plurality of times and registering them as a master image;
A photographing step of photographing an inspection area expected to have a defect on a substrate to be inspected at the same magnification as that of the master image through the optical system and registering the inspection area as a test image;
And a matching step of matching defects in the inspection area by matching the master image with the inspection image.

The method according to claim 1,
Wherein the registration step and the photographing step are respectively performed a plurality of times,
Wherein the registering step is performed at least once before the photographing step.

The method according to claim 1,
Wherein the matching step searches the defect by replacing an area corresponding to the inspection image on the master image with the inspection image.

The method according to claim 1,
And a defect processing step of, when the position of the defect is found through the determination step, processing the defect on the substrate to be inspected.

The method according to claim 1,
Wherein the optical system has a plurality of magnifications that can be converted,
Wherein the registering step registers the master image according to each magnification of the optical system.

6. The method according to any one of claims 1 to 5,
And determining a position of the defect using at least one of a position of the inspection image on the master image and a position of the defect on the inspection image after the matching step, Way.

The method according to claim 6,
Wherein the determining step sets the position of the defect on the master image to a first coordinate value and designates a position of the inspection image on the master image to a second coordinate value, And determining a position of the defect in the inspection image through a displacement between the second coordinate values.