WO2015037916A1

WO2015037916A1 - Method for determining validity of compensation matrix during substrate inspection

Info

Publication number: WO2015037916A1
Application number: PCT/KR2014/008470
Authority: WO
Inventors: 유희욱; 최종진; 정승원
Original assignee: 주식회사 고영테크놀러지
Priority date: 2013-09-12
Filing date: 2014-09-11
Publication date: 2015-03-19
Also published as: CN105557081B; CN105557081A; KR101444258B1

Abstract

The present invention relates to a method for determining the validity of a compensation matrix during substrate inspection. The method comprises the steps of: calculating coordinates of outermost pads within a measurement area (FOV) on a substrate; calculating coordinates of outermost feature objects within the FOV on the substrate; calculating the ratio of a second area, overlapping with a second polygon connecting a first polygon and the coordinates of the outermost feature objects, to a first area of the first polygon, connecting the coordinates of the outermost pads; and determining the validity of a compensation matrix by comparing the ratio and a predetermined reference value. It is possible to improve the reliability of inspection results of substrate inspection by determining the validity of a compensation matrix using the method.

Description

How to Determine the Effectiveness of Compensation Matrix in Substrate Inspection

The present invention relates to a method for determining the validity of a compensation matrix when inspecting a substrate. More specifically, the area of a second polygon including a coordinate of the outermost pads on the FOV and the coordinates of the outermost feature objects on the FOV is described. It relates to a method of determining the validity of the compensation matrix for compensating the position of the pad using.

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.

A conventional shape measuring apparatus sets a predetermined measuring area and checks whether a predetermined circuit element is properly formed in the measuring area.

The measurement 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 be distorted such as warp or distortion of the base substrate. This must be compensated because it can happen.

To this end, a compensation matrix may be generated by using a feature object such as a curved pattern or a hole pattern on the PCB to compensate for the pad position. In this case, whether the compensation matrix is valid may be a problem.

In order to solve the above technical problem, the present invention provides a method of determining the validity of the compensation matrix during the inspection of the substrate that can determine the validity of the compensation matrix generated by using the coordinates of the feature objects on the FOV to compensate the position of the pad on the FOV The purpose is to provide.

The object of the present invention is not limited to those mentioned above, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a method of determining the validity of a compensation matrix when inspecting a substrate, the method comprising: obtaining coordinates of outermost pads in a measurement area (FOV) on a substrate; Obtaining coordinates of outer feature objects; overlapping of the first polygon with a second polygon that connects coordinates of the outermost feature objects with respect to the first area of the first polygon that connects the coordinates of the outermost pads; Calculating a ratio of a second area, and validity of a compensation matrix generated by using coordinate values of feature objects in the FOV to compensate the coordinates of the pad in the FOV based on whether the ratio is equal to or greater than a preset reference value. Determining the step.

Coordinates of the outermost pads may be center coordinates of the outermost pads, and coordinates of the outermost feature objects may be central coordinates of the outermost feature objects.

The feature object may be at least one of a corner portion of a hole pattern, a circle pattern, or a curved pattern on the substrate.

The ratio may be determined as (the overlapping area of the first polygon and the second polygon) / the first area X 100.

The preset reference value may be 50.

The method may further comprise determining that the compensation matrix is valid when the ratio is greater than or equal to a preset reference value.

If the ratio is less than a preset reference value, the method may further include determining that the compensation matrix is invalid.

If the method includes a plurality of partitions in the FOV, each step is performed for each of the plurality of partitions, and the determining of the validity is performed by using a coordinate of a feature object in the partition. The validity of can be determined.

The plurality of partitions may be one of a plurality of panels or a plurality of components included in the FOV.

The substrate may be FPCB (FLEXIBLE PRINTED CIRCUIT BOARD).

According to the method of determining the validity of the compensation matrix during the inspection of the substrate according to the embodiment of the present invention, the reliability of the inspection of the substrate may be improved by determining the effectiveness of the compensation matrix generated by using the coordinates of the feature objects on the FOV.

Effects on the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a block diagram of a substrate inspection apparatus for determining the validity of a compensation matrix during substrate inspection according to an embodiment of the present invention.

2 is a flowchart illustrating a method of determining the validity of a compensation matrix when inspecting a substrate according to an exemplary embodiment of the present invention.

3 is an exemplary view illustrating a measurement area for explaining a method of determining validity of a compensation matrix during a substrate inspection according to an exemplary embodiment of the present invention.

4 is a diagram illustrating a state where a plurality of panels are arranged on the FOV when the substrate is an FPCB.

5 is a diagram illustrating a state in which a plurality of components are mounted in the same panel on the FOV when the substrate is an FPCB.

Objects and effects of the present invention, and technical configurations for achieving them will be apparent with reference to the embodiments described later in detail in conjunction with the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a known function or configuration may unnecessarily flow the gist of the present invention, the detailed description thereof will be omitted. The terms to be described later are terms defined in consideration of structures, roles, functions, and the like in the present invention, which may vary according to intentions or customs of users and operators.

However, the present invention is not limited to the embodiments disclosed below but may be implemented in various forms. The present embodiments are merely provided to complete the disclosure of the present invention, and to fully inform the scope of the invention to those skilled in the art, and the present invention is described only in the claims. It is only defined by the scope of the claims. Therefore, the definition should be made based on the contents throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

Hereinafter, with reference to the accompanying drawings, it will be described in detail preferred embodiments of the present invention.

1 is a configuration diagram of a substrate inspection apparatus for determining the validity of a compensation matrix during a substrate inspection according to an embodiment of the present invention, Figure 2 is a method of determining the effectiveness of the compensation matrix during a substrate inspection according to an embodiment of the present invention 3 is an exemplary view illustrating a measurement area for explaining a method for determining validity of a compensation matrix during a substrate inspection according to an exemplary embodiment of the present invention.

As shown in FIG. 1, the substrate inspection apparatus 100 controls the operation of the substrate inspection apparatus 100 and transfers and mounts a control unit 110 for processing an operation for performing various functions, and a substrate to be inspected. A memory unit storing a stage unit 120 to fix the measurement unit 130 for performing inspection on the substrate mounted on the stage unit 120 and a program and data for driving the substrate inspection apparatus 100 ( 140, a display unit 150 for outputting an operation state of the substrate inspection apparatus 100, an inspection result, and the like, and a user interface unit 160 for receiving a user's command.

First, the measurement area FOV is set on the substrate in order to set the inspection area. The measurement area FOV refers to a predetermined area set on the substrate in order to inspect whether the substrate is defective. For example, the measurement area FOV is a photographing range of a camera (not shown) included in the measurement unit 130. Field of view).

Subsequently, reference data for the measurement area FOV is obtained. The reference data may for example be a theoretical planar image of the substrate. The reference data may be obtained from CAD information or gerber information that records the shape of the substrate. The CAD information or Gerber information includes design reference information of the substrate, and generally includes layout information regarding pads, circuit patterns, hole patterns, and the like.

The reference data may be obtained from learning information obtained by the learning mode. In the learning mode, for example, the board 140 is searched for the board information in the memory unit 140, and if there is no board information, the bare board learning is performed. Subsequently, the bare board learning is completed, such as pads and wiring information of the bare board. When the information is calculated, the substrate information may be implemented in a manner such as storing 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 may be obtained by obtaining the learning information through the learning mode.

Next, the measurement data for the measurement area (FOV) is obtained. The measurement data may be an image of actually photographing the substrate corresponding to the reference data with the substrate inspection apparatus 100. The measurement data is similar to the reference data, but may be somewhat distorted compared to the reference data due to warpage or distortion of the substrate.

Therefore, in order to compensate for the distortion, a compensation matrix may be generated using the coordinates of the feature objects of the measurement area FOV, and the position of the pad on the measurement area FOV may be compensated using the coordinate matrix. The feature may be at least one of a corner portion of a hole pattern, a circle pattern, or a curved pattern on the substrate.

In this case, when the feature objects are not evenly distributed between the pads on the measurement area (FOV), but are concentrated and distributed among specific pads, the compensation matrix is a result for the position compensation of the specific pads. Is reliable, but the result is not reliable for position compensation for other pads. Therefore, a judgment on the validity of the compensation matrix is required.

Hereinafter, an embodiment of the present invention will be described in detail a method for determining the validity of the compensation matrix during substrate inspection.

2 and 3, first, the coordinates 210 of the outermost pads in the measurement area (FOV) 200 on the substrate are obtained (S100). Then, the coordinates 220 of the outermost feature objects in the FOV 200 on the substrate are obtained (S110).

The outermost pads and outermost feature objects in the FOV 200 refer to pads and feature objects that are closest to the FOV 200.

The first polygon P1 is formed by connecting the coordinates 210 of the outermost pads, and the second polygon P2 is formed by connecting the coordinates 220 of the outermost feature objects.

At this time, the ratio of the overlapping second area S2 of the first polygon S1 and the second polygon S2 to the first area S1 of the first polygon P1 is calculated (S120). ).

Then, the validity of the compensation matrix is determined by comparing the ratio with a preset reference value (S130). More specifically, the validity of the compensation matrix generated using the coordinate values of the feature objects in the FOV 200 to compensate for the coordinates of the pad in the FOV 200 based on whether the ratio is equal to or greater than a preset reference value. To judge.

In this case, the ratio may be used as an index of uniformity indicating that the feature objects in the FOV 200 are uniformly distributed in the pad. The larger the ratio, the higher the uniformity, which means that the effectiveness of the compensation matrix is higher.

Coordinates of the outermost pads may be center coordinates of the outermost pads, and coordinates of the outermost feature objects may be central coordinates of the outermost feature objects. However, in some cases, when the feature object is the same as the corner portion of the curved circuit pattern, the coordinate of the corner point may be set as the coordinate of the feature object.

The ratio may be specifically defined by Equation 1 below.

Equation 1

In addition, the preset reference value may be set to a reference value capable of guaranteeing the validity of the compensation matrix through a plurality of tests, which may be set in various cases.

For example, the preset reference value may be 50, which is merely an example and is not limited thereto.

On the other hand, step S130 may include determining that the compensation matrix is valid when the ratio is equal to or greater than a preset reference value, and determining that the compensation matrix is not valid when the ratio is less than the preset reference value. can do.

If the ratio is greater than or equal to the preset reference value, it is determined that the compensation matrix is valid and the compensation matrix is applied. If the ratio is less than the preset reference value, the compensation matrix is determined to be invalid and the current compensation matrix is not applied. The compensation matrix may be generated using the feature objects of the FOV and the neighboring FOV, and the validity of the compensation matrix may be determined by the above-described method.

By judging the effectiveness of the compensation matrix as described above, the reliability at the time of board inspection can be improved.

Hereinafter, as another embodiment of the present invention, a method of further improving the reliability of the compensation matrix validity determination method when inspecting a substrate when the substrate is a flexible printed circuit board (FPCB) will be described.

When the substrate is an FPCB, it is highly likely that a plurality of divided regions included in the FOV do not exist in the same plane due to the bending property of the FPCB. In this case, when generating the compensation matrix for the entire FOV and determining the validity thereof, it is highly likely that the reliability of the compensation matrix is lowered for each of the divided regions.

Therefore, according to the present embodiment, it is proposed to apply the compensation matrix validity determination method at the time of inspecting the substrate according to the embodiment of the present invention for each divided region in the FOV.

4 is a diagram illustrating a state where a plurality of panels are arranged on the FOV when the substrate is an FPCB. 5 is a diagram illustrating a state in which a plurality of components are mounted in the same panel on the FOV when the substrate is an FPCB.

For example, as shown in FIG. 4, when different panels, that is, the first panel 410 and the second panel 420, are positioned in the FOV 400, the first panel 410 may be bent due to bending of the FPCB. ) And the second panel 420 may be different from each other. Therefore, in applying the method for determining the validity of the compensation matrix when inspecting the substrate according to the embodiment of the present invention described above, a compensation matrix is generated for each of the first panel 410 and the second panel 420, After determining the validity of the compensation matrix for each of the first panel 410 and the second panel 420, the compensation matrix determined to be valid is applied to the first panel 410 and the second panel 420, respectively. Can be applied individually.

Meanwhile, even in the same panel, a method of determining a compensation matrix validity when inspecting a substrate according to an exemplary embodiment of the present invention may be applied by dividing an area.

For example, as shown in FIG. 5, when there are a plurality of components, that is, the first component 510 and the second component 520 in the same panel on the FOV 500, for each component, compensation After the matrix is generated and the validity of the compensation matrix is determined for each component, the compensation matrix determined to be valid may be individually applied to each component region.

In the above, as an example of the partition area, the panel and the component are exemplified, but this is only one example, and the partition area may be set in various ways within the FOV.

By the above method, the reliability of the compensation matrix can be further improved when the substrate is an FPCB.

As mentioned above, although embodiment of this invention was described, the person of ordinary skill in the art should add, change, delete, add, etc. the component within the range which does not deviate from the idea of this invention described in the claim. The present invention may be modified and changed in various ways, and it should be understood that the present invention is included in the scope of the present invention.

Claims

Obtaining coordinates of the outermost pads in the measurement area FOV on the substrate;

Obtaining coordinates of the outermost feature objects in the FOV on the substrate;

Calculating a ratio of an overlapping second area of the first polygon of the first polygon that connects the coordinates of the outermost pads to an overlapping second area of the second polygon that connects the coordinates of the outermost feature objects; ;

Comparing the ratio with a preset reference value to determine the validity of the compensation matrix;

Method of judging the validity of a compensation matrix during a board inspection.
According to claim 1,

The coordinates of the outermost pads are the center coordinates of the outermost pads, and the coordinates of the outermost feature objects are the central coordinates of the outermost feature objects.

Method of judging the validity of a compensation matrix during a board inspection.
According to claim 1,

The feature object is at least one of a corner portion of a hole pattern, a circle pattern or a curved pattern on the substrate,

Method of judging the validity of a compensation matrix during a board inspection.
The method of claim 1,

The ratio is

(Area overlapping area of the first polygon and the second polygon) / determined by the first area X 100,

Method of judging the validity of a compensation matrix during a board inspection.
The method of claim 1,

The preset reference value is 50

Method of judging the validity of a compensation matrix during a board inspection.
The method of claim 1,

The determining the validity is

Determining that the compensation matrix is valid when the ratio is above a preset reference value,

Method of judging the validity of a compensation matrix during a board inspection.
The method of claim 1,

The determining the validity is

If the ratio is less than a preset reference value, determining that the compensation matrix is invalid;

Method of judging the validity of a compensation matrix during a board inspection.
The method of claim 1,

The compensation matrix is generated using a feature object in the FOV,

Method of judging the validity of a compensation matrix during a board inspection.
The method of claim 1,

If the method includes a plurality of partitions in the FOV, each step is performed for each of the plurality of partitions,

The determining of the validity may include determining the validity of the compensation matrix generated by using the coordinates of the feature object in the partitioned area.

Method of judging the validity of a compensation matrix during a board inspection.
The method of claim 9,

The plurality of partitions may be one of a plurality of panels or a plurality of components included in the FOV.

Method of judging the validity of a compensation matrix during a board inspection.
The method of claim 9 or 10,

The substrate is FPCB (FLEXIBLE PRINTED CIRCUIT BOARD),

Method of judging the validity of a compensation matrix during a board inspection.