KR101132779B1 - Inspection method - Google Patents

Abstract

In order to set the inspection area in the inspection equipment for inspecting the substrate, the measurement area is set on the substrate, reference data for the measurement area is loaded, and measurement data for the measurement area is obtained. Subsequently, at least one feature block is set in units of blocks of predetermined shape information in the measurement area, and the shape information in the reference data corresponding to the feature block and the shape information in the measurement data corresponding to the feature block are compared to the reference data. And a conversion relationship between the measurement data. By using the transformation relationship, the inspection area for inspecting the measurement object in the measurement area is set by compensating for the distortion. Accordingly, it is possible to set an accurate inspection area that compensates for the distortion.

Description

Inspection method {INSPECTION METHOD}

The present invention relates to an inspection method, and more particularly to an inspection method for the measurement object of the shape measuring device.

In general, at least one printed circuit board (PCB) is provided in an electronic device, and various circuit elements such as a circuit pattern, a connection pad part, and a driving chip electrically connected to the connection pad part are provided on the printed circuit board. Are mounted.

In general, a shape measuring device is used to confirm that the various circuit elements as described above are properly formed or disposed on the printed circuit board.

The conventional shape measuring apparatus sets a predetermined inspection area to check whether a predetermined circuit element is properly formed in the inspection area. In the conventional inspection area setting method, the area where a circuit element should exist is simply set as the inspection area in theory.

The inspection area must be set correctly at the desired location to measure the circuit elements that require measurement.However, the measurement object such as a printed circuit board may have distortion such as warp and distortion of the base substrate. Since it may occur, the conventional inspection area may not be accurately set at a desired position for measurement, and there is a problem in that an image acquired by a camera of the photographing unit may have a certain difference from a position where a circuit element is actually present.

Therefore, there is a need for setting an inspection area that adequately compensates for the distortion of the measurement object as described above.

Therefore, the problem to be solved by the present invention is to set the inspection area to compensate for the distortion of the measurement object, and through the feature value setting and verification step including a plurality of shape patterns when similar patterns are adjacent to the substrate It is to provide an inspection method that can accurately set the inspection area.

According to an exemplary embodiment of the present invention, a method of setting a measurement area includes: setting a measurement area on a substrate, importing reference data for the measurement area, and obtaining measurement data for the measurement area. Setting at least one feature block based on predetermined shape information in the measurement area on a block basis; shape information in the reference data corresponding to the feature block and the measurement data corresponding to the feature block. Comparing the shape information therein, obtaining a conversion relationship between the reference data and the measurement data, and setting the inspection area for inspecting the measurement object in the measurement area using the conversion relationship by compensating for distortion. It includes.

According to an embodiment, the shape information may be plural, and in this case, at least two or more shape information of the plurality of shape information may be the same shape.

For example, the shape information may have a two-dimensional separator.

In an embodiment, the feature block may be set in plural, and acquiring a conversion relationship between the reference data and the measurement data comprises selecting at least two feature blocks from the feature blocks. And obtaining a quantified conversion formula between the reference data and the measurement data using the selected two or more feature blocks. In this case, the quantified transformation formula may be configured by using at least one of a position change, a slope change, a size change, and a degree of deformation obtained by comparing the reference data and the measurement data for the selected two or more feature blocks. Can be set.

In an embodiment, the setting of the feature block may include setting a comparison feature block for comparing the shape information and setting a verification feature block for verifying the validity of the inspection region of the set measurement object. It may include a step. In this case, the inspection method may further include determining whether the inspection region of the set measurement object is valid using the verification feature block. The determining of whether the inspection area is valid may include: converting the verification feature block using the transformation relationship, measuring the verification feature block, the converted feature block, and the measured verification block. Comparing the feature blocks to determine whether the position difference is within an allowable range, and resetting the conversion relationship when the feature block is out of the allowable range.

For example, the reference data may be obtained from CAD information or gerber information about the substrate, or may be obtained from learning information obtained by a learning mode.

In an embodiment, the method may further include overlaying the reference data and the measurement data. In this case, the inspection method may further include removing a noise pattern in the feature block by using the overlay.

In an embodiment, the setting of the feature block may include receiving the feature block from an operator based on the reference data and the measurement data.

According to the present invention, a feature block is set based on predetermined shape information in a measurement area set on a substrate in units of blocks, the shape data of the reference data and the measurement data are compared with the feature block, and the reference data and the measurement are performed. By acquiring the conversion relationship between the data, the inspection area can be set more accurately.

In addition, even when similar patterns are adjacent to the substrate, the feature block can be specified without a mistake, and the inspection region can be accurately set through the feature block setting and verification step including a plurality of shape patterns.

In addition, when the shape information in the feature block is plural, the conversion relationship can be obtained more accurately, and even when at least two or more pieces of shape information are the same, the possibility of a mistake can be reduced by comparing the shape information to one block. .

Further, even when the shape information in the feature block is set to have a two-dimensional delimiter, it is possible to reduce the possibility of a mistake when comparing the shape information.

In addition, since it is possible to perform an operation such as defect inspection of parts based on the inspection area set as described above, it is possible to more accurately determine whether the substrate is defective or the like.

1 is a flow chart showing a test method according to an embodiment of the present invention.
2 is a plan view illustrating an example of reference data in the inspection method of FIG. 1.
3 is a plan view illustrating an example of measurement data in the inspection method of FIG. 1.
4 is a flowchart illustrating an embodiment of a method of obtaining a transformation relationship between reference data and measurement data.
5 is a flowchart illustrating an embodiment of a method of verifying whether a set inspection area is valid.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described in the specification, and that one or more other features It should be understood that it does not exclude in advance the possibility of the presence or addition of numbers, steps, actions, components, parts or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art.

Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

1 is a flow chart showing an inspection method according to an embodiment of the present invention, Figure 2 is a plan view showing an example of the reference data in the inspection method of Figure 1, Figure 3 is one of the measurement data in the inspection method of FIG. It is a top view which showed the example.

1 to 3, in order to set an inspection region in which distortion is compensated according to an embodiment of the present invention, a field of view (FOV) is first set on a substrate (S110).

The measurement area (FOV) means a predetermined area set on the substrate in order to inspect the substrate for defects, for example, based on a photographing range of a camera mounted on inspection equipment such as a 3D shape measuring device. Can be set.

Subsequently, reference data RI for the substrate including the target area is loaded (S120). The reference data RI may be a theoretical planar image of the substrate, for example, as shown in FIG. 2.

In one embodiment, the reference data (RI) may be obtained from the CAD (CAD) information or the gerber information recording the shape of the substrate. The CAD information or Gerber information includes design reference information of the substrate, and generally includes layout information regarding the pad 10, the circuit pattern 30, the hole pattern 40, and the like.

In another embodiment, the reference data (RI) may be obtained from the learning information obtained by the learning mode. In the learning mode, for example, the board information is searched in a database, and if there is no board information as a result of the database search, the learning of the bare board is performed. If is calculated may be implemented in such a manner as to store the substrate information in the database. That is, the design reference information of the printed circuit board is obtained by learning a bare board of the printed circuit board in the learning mode, and the reference data (RI) may be obtained by obtaining the learning information through the learning mode.

Next, measurement data PI for the measurement area FOV is obtained (S130).

For example, as shown in FIG. 3, the measurement data PI may include a component 20 mounted on a substrate, a terminal 22, a polarity display 24 formed on the component, a circuit pattern 30, and a hole. It may be a photographed image of the actual printed circuit board on which 42 is shown. The measurement data PI illustrated in FIG. 3 is illustrated as having the same image as the reference data RI illustrated in FIG. 2 except that an additional configuration of the component 20 and the like appears. The substrate is distorted as compared with the reference data RI due to the warpage and the warpage of the substrate.

In one embodiment, the measurement data (PI) is irradiated with light to the measurement area (FOV) by using the illumination unit of the inspection equipment, and photographing the reflection image of the irradiated light using a camera mounted on the inspection equipment Can be obtained. In another embodiment, the measurement data PI is irradiated with the grid pattern light to the measurement area (FOV) by using the grid pattern illumination unit of the inspection equipment, and by taking a reflection image of the irradiated grid pattern light 3D shape After acquiring data about, the data about the three-dimensional shape may be averaged.

Next, at least one feature block is set based on predetermined shape information in the measurement area FOV in units of blocks (S140).

Since the predetermined shape information is in blocks, it may be more accurate than the method of comparing the reference data RI and the measurement data PI based on coordinates of a broken point, a circle, and a hole. .

Since a plurality of bent points, circles, and the like exist on the substrate, when the bent points 30a and 30b are adjacent to each other or the circle frames 40a and 40b are adjacent to each other, as shown in FIGS. 2 and 3. It may be confused when the bent points 30a and 30b and the circle frame 40a and 40b are prepared between the reference data RI and the measurement data PI. For example, the break point 30a disposed above the reference data RI may be compared with the break point 30b disposed below the measurement data PI, or below the reference data RI. An error may occur in which the arranged circle 40b is prepared compared to the circle 40a disposed above the measurement data PI. In addition, when the circle 40 and the hole 42 shown in FIGS. 2 and 3 are contrasted, the hole 42 may be displaced as shown in FIG. This can be difficult to prepare accurately.

On the other hand, since the shape formed in the feature block is very diverse, as compared with the block shape information between the reference data (RI) and the measurement data (PI) as in an embodiment of the present invention for the specific object of the comparison object Error can be prevented.

When setting the feature block, in case of setting a feature block having the same shape repeatedly around, when comparing the shape information in the feature block between the reference data (RI) and the measurement data (PI) An error may occur for a particular. Thus, the feature block can be set such that the possibility of a mistake in the shape information in the feature block due to surrounding shape information is eliminated.

In addition, in order to eliminate the possibility of false positives, the feature block may be set to have a two-dimensional separator. Specifically, the feature block is set in each of the reference data (RI) and the measurement data (PI) as shown in Figures 2 and 3 of the reference data (RI) corresponding to the set feature block Since shape information and shape information of the measurement data PI are compared with each other, a two-dimensional separator capable of defining a two-dimensional plane in order to accurately match two shape information may be provided. For example, the feature block may include various lines, quadrangles, circles, and combinations thereof.

The feature block may be set in one or plural in the inspection area. For example, as shown in FIGS. 2 and 3, the reference block RI and the measurement data PI may have two elements. The first and second feature blocks FB1 and FB2 may be set.

For example, shape information in a block of the feature block may be plural as in the second feature block FB2, and thus the conversion relationship may be more accurately obtained. In this case, at least two or more shape information of the plurality of shape information may be the same shape. That is, even when at least two or more pieces of shape information are the same, the possibility of a mistake can be reduced by comparing the shape information with one block.

In this case, the plurality of shape information may have a two-dimensional delimiter, thus reducing the possibility of false in comparing the shape information.

The feature block may be set first in the reference data (RI) and then set a corresponding feature block in the measurement data (PI), or first in the measurement data (PI) and then in the reference data (RI). The corresponding feature block may be set. That is, when a feature block is set in one of the measurement data PI and the reference data RI, a corresponding part may be detected in the other one.

Meanwhile, before setting the feature block, the reference data RI and the measurement data PI may be overlayed. The feature block may be set to eliminate the possibility of false recognition after overlaying the reference data RI and the measurement data PI. The overlay may include both a concept of physically overlaying images corresponding to the reference data (RI) and the measurement data (PI), and a concept of abstractly overlaying the reference data (RI) and the measurement data (PI). Can be. The overlay of the reference data RI and the measurement data PI may be performed to verify the inspection region set after the inspection region to be described later is set.

In one embodiment, the feature block may be set manually. In detail, the feature block may be set by an operator based on at least one of the reference data RI and the measurement data PI, or based on the overlaid reference data RI and the measurement data PI. Can be. For example, the operator may set predetermined blocks including two-dimensional separators spaced to some extent within the measurement area FOV as the feature block. In this case, the operator may set the feature block into a plurality of areas evenly distributed in the measurement area FOV.

In another embodiment, the feature block may be set automatically. Specifically, the feature block may be set by image analysis. In this case, the feature block may be set to a plurality of areas evenly distributed in the measurement area (FOV).

Meanwhile, the noise pattern in the feature block may be removed using the overlay. For example, the measurement data PI may include a silk pattern printed on a bare substrate differently from the reference data RI. Therefore, in order to contrast accurate shape information, the silk pattern is first excluded from the measurement data PI or overlaid the reference data RI and the measurement data PI, and then the excluded measurement data PI. For the feature block can be set.

Next, shape information in the reference data corresponding to the feature block and shape information in the measurement data corresponding to the feature block are compared to obtain a conversion relationship between the reference data and the measurement data (S150).

4 is a flowchart illustrating an embodiment of a method of obtaining a transformation relationship between reference data and measurement data.

Referring to FIG. 4, first, at least two or more feature blocks are selected from the plurality of feature blocks (S152). For example, the selected feature block may be the first and second feature blocks FB1 and FB2 of FIGS. 2 and 3.

Subsequently, a quantified conversion formula between the reference data RI and the measurement data PI is obtained using the selected two or more feature blocks FB1 and FB2 (S154). The measurement data PI is distorted as compared with the reference data RI corresponding to theoretical reference information due to warpage and warpage of the substrate. The conversion formula is a formula for mathematically converting the reference data (RI) into the measurement data (PI) to compensate for the distortion degree. The quantified conversion formula may include a position change, a slope change, a size change, and the like obtained by comparing the measurement data PI with the reference data RI for the selected two or more feature blocks FB1 and FB2. It may be set using at least one of the deformations.

Meanwhile, as an example, the conversion formula may be obtained by using Equation 1.

In Equation 1, P _CAD is a coordinate of a target according to CAD information or Gerber information, that is, a coordinate in the reference data RI, and f (tm) is a transformation matrix as a transfer matrix. P _real is a coordinate of the target in the measurement data PI obtained by the camera. When the theoretical coordinate P _CAD in the reference data RI and the actual coordinate P _real in the measurement data PI are obtained, the transformation matrix can be known.

For example, the transformation matrix may include a coordinate transformation matrix according to an affine transformation or a perspective transformation in which a point correspondence relationship in an n-dimensional space is represented by a first-order equation. In order to define the coordinate transformation matrix, the number of feature blocks may be appropriately set. For example, three or more feature blocks may be set in the case of an affine transform and four or more feature blocks may be set in the perspective transform.

Referring back to FIGS. 1 to 3, the inspection area for inspecting the measurement object in the measurement area is set by compensating for distortion by using the transformation relationship (S160).

For example, the measurement data PI may be converted using a conversion value of a distortion degree of the measurement object obtained by the conversion relationship, or the equation may be converted by applying a formula relating to the conversion relationship to the reference data RI. Thus, the inspection area for inspecting the measurement object can be set.

The conversion relationship compensates for the distortion generated in the measurement data PI compared to the reference data RI, so that the set inspection area is closer to the shape of the actual substrate with respect to the original measurement area FOV. can do. Although the setting of the inspection area may be performed for all of the measurement areas FOV, it may be performed only for a predetermined inspection area to be inspected.

For example, if a predetermined inspection area to be inspected is set and an inspection area in the measurement data PI is set using the conversion relationship, the connection state of the components in the inspection area can be inspected. . In this case, the inspection may use the measurement data PI acquired in the step S130 of obtaining measurement data PI for the measurement area FOV.

Next, it is optionally possible to verify whether the set inspection area is valid (S170).

In one embodiment, for the verification, in addition to the feature block (hereinafter referred to as a "comparison feature block") for the comparison of the shape information set in the step of setting the feature block (hereinafter referred to as "comparison feature block"), A feature block (hereinafter, referred to as a “validation feature block”) for verifying validity may be additionally set. The comparison feature block and the verification feature block may be simultaneously set in the setting of the feature block (S140), and the verification feature block may be set later.

Accordingly, the verification feature block may be used to determine whether the inspection area of the set measurement object is valid.

5 is a flowchart illustrating an embodiment of a method of verifying whether a set inspection area is valid.

Referring to FIG. 5, first, the verification feature block is transformed using the transformation relationship, and the converted feature block is compared with the actually measured verification feature block (S172).

Since the shape information of the transformed verification feature block is present in the inspection area set with distortion compensated according to the conversion relationship, in principle, the shape information of the transformed feature block for position verification substantially matches the shape information of the actual measured feature block for verification. In this case, it can be seen that the set inspection area is valid.

Subsequently, it is determined whether the difference in the position of the comparison result is within an allowable range (S173).

For example, after setting the position where the shape information of the transformed verification feature block is arranged as a coordinate, and setting the position where the shape information about the actually measured verification feature block is arranged as the coordinate, the coordinate When comparing them, make sure that the difference is within the specified tolerances. The allowable range may be defined according to the size of the substrate, a criterion for determining the quality of the substrate, and the like.

Subsequently, the set inspection area is verified (S174).

Specifically, when the difference between the arranged positions is within the allowable range, it is determined that the set inspection area is valid, and when it is not within the allowable range, it is determined that it is not valid. If it is determined that it is not valid, the above-described processes may be repeated to reset the conversion relationship.

According to the present invention as described above, the feature blocks FB1 and FB2 are set in block units based on predetermined shape information in the measurement area FOV set on the substrate, and the reference is made to correspond to the feature blocks FB1 and FB2. By comparing the shape information of the data RI and the measurement data PI and obtaining a conversion relationship between the reference data RI and the measurement data PI, the inspection area can be set more accurately.

Further, when the shape information in the feature blocks FB1 and FB2 is plural, the conversion relationship can be obtained more accurately, and even when at least two or more pieces of shape information are the same, a possibility of making a mistake by comparing the shape information to one block is possible. Can be reduced.

Further, even when the shape information in the feature blocks FB1 and FB2 is set to have a two-dimensional separator, the possibility of a mistake in the comparison of the shape information can be reduced.

In addition, since it is possible to perform an operation such as defect inspection of parts based on the inspection area set as described above, it is possible to more accurately determine whether the substrate is defective or the like.

While the present invention has been described in connection with what is presently considered to be practical and exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Therefore, the above description and the drawings below should be construed as illustrating the present invention, not limiting the technical spirit of the present invention.

<Short Description of Main Drawing Numbers>
10: pad 20: parts
22: terminal 30: circuit pattern
40: circle 42: hall
FB1: first feature block FB2: second feature block
PI: Measurement Data RI: Reference Data

Claims (12)

Setting a measurement area on the substrate;
Importing reference data for the measurement area;
Acquiring measurement data for the measurement area;
Setting at least one feature block based on predetermined shape information in the measurement area in units of blocks, and receiving the feature block from an operator based on the reference data and the measurement data;
Comparing shape information in the reference data corresponding to the feature block with shape information in the measurement data corresponding to the feature block to obtain a conversion relationship between the reference data and the measurement data; And
And a compensation area for compensating for a distortion and setting the inspection area for inspecting a measurement object in the measurement area by using the conversion relationship. The method of claim 1,
And the shape information is plural. The method of claim 2,
At least two or more shape information of the plurality of shape information is characterized in that the same shape. The method of claim 2,
And the shape information has a two-dimensional separator. The method of claim 2,
The feature block is set in plural,
Acquiring a conversion relationship between the reference data and the measurement data,
Selecting at least two feature blocks from the plurality of feature blocks; And
Obtaining a quantified conversion formula between the reference data and the measurement data using the selected two or more feature blocks. The method of claim 5, wherein the quantified conversion formula is
And at least one of a position change, a tilt change, a size change, and a deformation degree obtained by comparing the reference data and the measurement data with respect to the selected two or more feature blocks. The method of claim 1, wherein the reference data,
The method of claim 1, which is obtained from CAD information or gerber information on the substrate, or from learning information obtained by a learning mode. Setting a measurement area on the substrate;
Importing reference data for the measurement area;
Acquiring measurement data for the measurement area;
Setting at least one feature block based on predetermined shape information in the measurement area in units of blocks;
Comparing shape information in the reference data corresponding to the feature block with shape information in the measurement data corresponding to the feature block to obtain a conversion relationship between the reference data and the measurement data; And
Compensating for and setting distortion in an inspection area for inspecting a measurement object in the measurement area by using the conversion relationship;
Setting the feature block,
Setting a comparison feature block for comparing the shape information; And
Setting a verification feature block for validating an inspection region of the measurement object;
The inspection method further comprises the step of determining whether the inspection region of the set measurement object is valid using the verification feature block. The method of claim 8, wherein determining whether the inspection area is valid comprises:
Converting the verification feature block using the transformation relationship;
Measuring the verification feature block;
Comparing the transformed feature block with the measured verification feature block to determine whether a position difference is within an allowable range; And
And resetting the conversion relationship if the allowance is out of the allowable range. Setting a measurement area on the substrate;
Importing reference data for the measurement area;
Acquiring measurement data for the measurement area;
Overlaying an image corresponding to the reference data and an image corresponding to the measurement data;
Setting at least one feature block based on predetermined shape information in the measurement area in units of blocks;
Comparing shape information in the reference data corresponding to the feature block with shape information in the measurement data corresponding to the feature block to obtain a conversion relationship between the reference data and the measurement data; And
And a compensation area for compensating for a distortion and setting the inspection area for inspecting a measurement object in the measurement area by using the conversion relationship. The method of claim 10,
And removing a noise pattern in the feature block by using an image in which the image corresponding to the reference data and the image corresponding to the measurement data are overlaid. The method of claim 8, wherein the setting of the feature block comprises:
And receiving the feature block from the operator based on the reference data and the measurement data.

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