KR20240076281A - System for measuring the position of the object to be inspected - Google Patents

Abstract

The purpose of the present invention is to provide an inspection system that can accurately and efficiently inspect the positions of multiple inspection objects formed on a substrate.
In accordance with the above purpose, the present invention configures the alignment mark, which aligns the position of the substrate and the position of the inspection object, by aligning a plurality of marks arranged radially with each other, rather than a single point, to set the focus area, thereby improving the precision of alignment. Raise.
Using the plurality of alignment marks as described above, the position of each inspection object in one row arranged along one axis on the substrate is verified, and the position of each inspection object arranged in each column belonging to each row is verified. Provides an inspection system that calculates the positional deviation value of an individual inspection object by vectorically summing the positional deviation values measured in rows and columns.

Description

{System for measuring the position of the object to be inspected}

The present invention relates to a system for measuring displacement of an inspection object on a substrate.

Multiple dies are formed on a semiconductor wafer, and each die must be positioned accurately to prevent defects from occurring in subsequent processes. In addition to silicon wafers, in products such as display devices and solar cells that use glass substrates or flexible polymer substrates, the positional accuracy of the square area to be manufactured as a single device module on the substrate must also be carefully inspected. Glass substrates can also be applied to semiconductor devices, and the position of an inspection object, such as a die formed on the substrate, must be thoroughly inspected at the beginning to detect defective substrates in order to efficiently proceed with subsequent processes. For example, when a via hole is formed at a certain location on the inspection object, if the inspection object is not accurately positioned and is distorted, the via hole will not be able to function properly and the entire substrate on which the process has been performed will be judged defective. Therefore, before carrying out the process, The location of the test objects must be verified.

There are alignment marks for accuracy in the position of the board and inspection object. The alignment mark usually consists of a single dot or has a cross shape as suggested in Patent Publication No. 10-2003-0075352. In this way, an alignment mark with a single inspection reference point is highly likely to cause errors in the inspection coordinate system due to external factors such as alignment degree and distortion, and there is a problem in that correction is impossible when an error occurs in the inspection reference point itself. When checking the positions of multiple inspection objects using this single-configuration alignment mark, errors accumulate.

The purpose of the present invention is to provide an inspection system that can accurately and efficiently inspect the positions of multiple inspection objects formed on a substrate.

In accordance with the above purpose, the present invention configures the alignment mark, which aligns the substrate position and the inspection object position, by aligning a plurality of radially arranged marks with each other, rather than a single point, to set the focus area, thereby improving the alignment precision. Raise.

Using the plurality of alignment marks as described above, the position of each inspection object in one row arranged along one axis on the substrate is verified, and the position of each inspection object arranged in each column belonging to each row is verified. Provides an inspection system that calculates the positional deviation value of an individual inspection object by vectorically summing the positional deviation values measured in rows and columns.

According to the present invention, since the alignment mark is selected by aligning a plurality of marks arranged radially, an accurate reference point can be determined.

In addition, with respect to the single reference alignment mark, the positional misalignment of the inspection objects arranged in one row is measured, and then, based on the alignment mark of the inspection objects belonging to the first row, the positional misalignment of the inspection objects arranged in each row is measured. Since the positional deviation values of individual inspection objects are calculated by vectorically summing the positional deviation values measured in rows and columns, the positional deviation of the inspection object can be measured quickly and accurately in a non-contact manner by scanning the entire board with a vision camera. You can.

Figure 1 is a plan view showing the alignment mark, which is a standard for determining the positional accuracy of the substrate itself and the positional misalignment of inspection objects, composed of multiple marks.
FIGS. 2A and 2B are schematic diagrams for schematically illustrating a method of measuring the positional deviation of each inspection object on a substrate.
Figure 3 is a diagram showing the measurement of positional deviation for inspection objects arranged in one row on a substrate.
Figure 4 is a diagram showing measurement of positional deviation for each row of inspection objects on a board.

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

Figure 1 is a plan view showing the alignment mark, which is a standard for determining the positional accuracy of the substrate itself and the positional misalignment of inspection objects, composed of multiple marks.

The board has so-called global marks that align the position of the board itself and general alignment marks that allow you to check the positions of inspection objects arranged on the board. The existing alignment mark consists of a single inspection reference point consisting of one dot, as shown on the left side of Figure 1. Therefore, there is a high possibility that an error in the inspection coordinate system may occur due to external factors such as the degree of alignment or distortion of the inspection object, and there is a problem that correction is impossible when an error occurs in the inspection reference point itself. Therefore, in the present invention, the alignment mark itself consists of four radial points and multiple inspection reference points as their radial center points, as shown on the right side of FIG. 1. The radial points are substantially equally spaced around the circumference of a circle, with the central point being the center of the circle.

That is, the alignment mark of the present invention is radially symmetrical and includes a plurality of points arranged radially, and the center point of the radial symmetry is used as the alignment inspection reference point. These alignment marks can minimize the possibility of inspection coordinate system errors. In other words, since it includes a number of points arranged radially, if an error occurs in the position of one of them, the error caused by the positions of other inspection reference points can be compensated, so the alignment reference point itself, which is specified as the center, has an error. Few.

As shown in FIG. 2, the alignment marks of these multiple inspection reference points are formed as a global mark 20 for position alignment of the entire substrate and an object alignment mark 30 for confirming the position of each inspection object 10. The global mark includes a first global mark formed on the upper left side of the substrate, a second global mark formed on the upper right side on a horizontal line (on the There is a third global mark with . In the above, the inspection object 10 may refer to a die including a plurality of via holes. In other words, the inspection object 10 is one unit including a certain number of holes, and each of the four corners of the inspection object 10, which is each unit, has an alignment mark (align mark 1, align mark 2, align mark 3). , an alignment mark 4) is formed, and the position of the inspection object is measured by measuring the position of the alignment mark with respect to the global mark. Once the position of the inspection object is measured, the location of each hole included in the inspection object is based on the position of the alignment mark of the inspection object (e.g., alignment mark 1: located in the upper left corner of the inspection object). It can be measured.

Object alignment marks for each inspection object 1, 2,..., n are formed on the upper left and right sides and lower left and right sides of each inspection object, so that it appears as if all square corners of the inspection object are marked. At this time, object alignment marks between adjacent inspection objects are shared. For example, if 6 inspection objects are arranged in 2 rows and 3 columns, an object alignment mark is formed at the upper left of each inspection object in each row, and an object alignment mark is formed at the upper right of the inspection object arranged at the end of each row. Configure further. In addition, an object alignment mark is added to the bottom left of the test object arranged at the end of each row, and an object alignment mark is added to the bottom right of the final test object arranged in the last column of the last row. Therefore, if there are 6 inspection objects arranged in 2 rows and 3 columns, a total of 12 object alignment marks are formed. Figure 2 illustrates a total of 56 test objects arranged in 7 rows and 8 columns, but the number of test objects can be changed.

Figure 2 schematically explains a method of measuring the positional distortion of each inspection object 10 on a substrate, and calculates the distortion of the inspection object 10 based on the global mark 20. The basic concept is to calculate the amount of distortion of the inspection object by measuring the distortion in the row direction and the distortion in the column direction and adding them vectorially. The amount of distortion is determined by measuring the position of the alignment mark 30 using a vision camera, and the measured amount is transmitted to the computer and processed through calculations in the program module.

For example, in the case of test object number 18 in FIG. 2, the row direction deviation amount A ₂ of test object number 2 in row 1 and 18 in the third row in the column direction from the first test object number 2 in column 2 (row 3) The amount of thermal distortion is measured by B ₂₃ , which is the measurement of the position of the object's alignment mark, and the total amount of distortion of object No. 18 is A ₂ + B ₂₃ (vector sum).

Meanwhile, in the present invention, since distortion is measured using a vision camera, there is a limit to the amount of inspection object that can be covered in one measurement. Therefore, the present invention constitutes the following surveying method.

First, the position alignment of the substrate itself is determined by checking the positions of the three global marks.

Next, using the first global mark as a reference point, the amount of distortion (A ₁ , A ₂ ,...A _j ) of each inspection object located in row 1 is measured. Since the vision camera's field of view is narrow and long, the amount of distortion is measured only for one row based on the first global mark. As shown in Figure 3, the object alignment mark located in the upper left corner, which is the object alignment mark formed close to the first global mark, is used as the measurement object, and A ₁ and A ₂ , which are the row direction deviation amounts of each inspection object in one row, are measured. ,...Measure A _j .

If the measurement direction of the vision camera is fixed to spread out long along the column direction (Y-axis direction) and form a narrow band in the row direction (X-axis direction), rotate the substrate 90 degrees and arrange one row in the Y-axis direction. As described above, the amount of row direction deviation of the inspection objects in one row is measured.

Accordingly, the amount of row direction deviation of the first inspection object in each row is determined. Figure 3 illustrates measurements from A ₁ to A ₈ (A ₁ , A ₂ , A ₃ , A ₄ , A ₅ , A ₆ , A ₇ , A ₈ ).

Next, measure the amount of column distortion of the inspection objects in row 1. In other words, the amount of misalignment B ₂ , B ₃ , etc. of each test object arranged at the bottom of the row is measured using the object alignment mark at the top left of test object 1 as a reference point. In the case of inspection object No. 1, since it is in 1st row and 1st column, the amount of distortion is determined vectorially by measuring the amount of distortion by the first global mark. Therefore, the amount of distortion of inspection objects in 2 rows or less is calculated based on this. Measure. In other words, B ₁ is the same as A ₁ , and B ₂ is the deviation value measured from A ₁ (or B ₁ ). Therefore, the total amount of distortion of each test object in row 1 is A ₁ + B _1i (i=2,3,..). Figure 4 shows the measurement of positional deviation for each row as described above.

The amount of distortion of each inspection object in two rows is calculated by measuring A ₂ based on the object alignment mark and adding A ₂ vectorially. Therefore, the total amount of distortion of the test objects in row 2 is A ₂ + B _2i (i=2,3,..). In this way, the amount of distortion of all inspection objects on the board is measured for each row.

As described above, when measuring the amount of distortion in one row, the substrate is rotated 90 degrees, and when measuring the distortion for each column, it is rotated again -90 degrees and returned to the original position for measurement.

Vector summation adds (x,y) values for each component in the case of rectangular coordinates. The same goes for polar coordinates (r, θ).

In this way, after precise alignment of the substrate, the position of each inspection object can be precisely measured in a non-contact manner using a vision camera, and quick results can be produced even if multiple inspection objects are arranged on a large-area substrate. You can.

As a modification to the above embodiment, measuring the amount of positional deviation of inspection objects in one row from the first global mark in the upper left corner may be performed by moving from right to left based on the second global mark in the upper right corner. . These modifications are included in the technical spirit of the present invention. In other words, if the position of the inspection objects is viewed in rows and columns, the amount of distortion is measured for one row, and then the amount of distortion of the inspection objects included in each row is measured using the inspection objects belonging to row 1 as a secondary reference point, the present invention included in

In addition, the inspection system of the present invention installs a vision camera and lighting on the upper part of the glass substrate (at an upper position spaced apart from the glass substrate) to measure the positions of the inspection objects, and installs a vision camera and lighting on the lower part of the glass substrate (either in close contact with the lower surface of the glass substrate or It can be configured by installing a reflector that can reflect light at a lower position spaced apart from the glass substrate. Installation of a reflector provides images of inspection objects with high resolution and without noise.

Meanwhile, in a modification of the above embodiment, only global marks are formed on the glass substrate on which the inspection object is formed, and alignment marks are formed not on the glass substrate but on a frame that is in contact with and aligned with another external object, for example, the side of the substrate. Thus, the substrate can be placed on the frame on which the alignment marks are formed and the position of the inspection object can be inspected. Alignment marks are formed at regular intervals on a square frame and have fixed position coordinates relative to the global mark, and each inspection object has its position measured based on the coordinates of the alignment mark closest to itself. The vision camera captures as much as it enters the field of view, then scans and takes pictures. In other words, for example, the method is to take pictures of the inspection objects in the first row, measure their positions, and then scan for a predetermined width and take pictures of the second row.

Unless otherwise defined in the above description, all technical and scientific terms used in this specification have the same meaning as commonly understood by an expert skilled in the technical field to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless clearly specifically defined. When it is said that a part "includes" a certain element throughout the specification, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary. Additionally, the singular form may include the plural form depending on the context.

In addition, in this specification, “on or above” means located above or below the target portion, and does not necessarily mean located above the direction of gravity. Additionally, when a part of a region, plate, etc. is said to be “on or above” another part, this does not only mean that it is in contact with or at a distance “directly on or above” another part, but also that there is another part in between. Also includes cases where there are. This is interpreted the same way in the word “~ at the bottom.”

Additionally, in this specification, terms such as “first, second” may be used to describe various components, but the components are not limited by the terms, and the terms refer to one component as another component. It is used only for the purpose of distinguishing from elements.

The rights of the present invention are not limited to the embodiments described above but are defined by the claims, and those skilled in the art can make various changes and modifications within the scope of the claims. This is self-evident.

10: Test object
20: Global mark
30: Align mark

Claims (8)

An alignment mark formed on a substrate or wafer to align the position of the substrate or wafer, with a plurality of points arranged radially at intervals from each other, the plurality of points forming radial symmetry, and the center point of the radial points being aligned. An alignment mark characterized by using it as a reference point. A substrate or wafer containing the alignment mark of claim 1. The method of claim 2, wherein the alignment mark includes a global mark formed for verifying the position of the substrate or wafer and an object alignment mark formed for verifying the position of a plurality of inspection objects formed on the substrate or wafer,
The global mark includes a first global mark and a second global mark each formed at both ends lying on a horizontal line on the top of the substrate or wafer, and a third global mark arranged at a predetermined distance in a vertical line from the first global mark, ,
Object alignment marks are formed on the upper left and right sides and lower left and right sides of each inspection object and exist adjacent to the square corners of each inspection object, and the object alignment marks between adjacent inspection objects are shared by adjacent inspection objects. A substrate or wafer characterized by being arranged. A system for measuring the positional deviation of an inspection object on a substrate or wafer,
The substrate or wafer of claim 3;
A vision camera capable of recognizing images of global marks and object alignment marks on the substrate or wafer; and
It includes a program module that calculates the amount of positional deviation of the inspection object measured by the vision camera,
Divide the locations of test objects into rows and columns,
Using a vision camera, measure the amount of distortion (A ₁ , A _{2 ,...A i ) for each inspection object belonging to row 1 using the first global mark as a reference point, and then measure the amount of distortion (A 1 , A 2} ,...A _i ) belonging to row 1. Using the alignment mark of each test object as a secondary reference point, the amount of deviation of the test objects included in each row is (B ₁₂ , B ₁₃ ,...B _1j ), (B ₂₂ , B ₂₃ ,...B _2j ),...,(B _i2 , B _i3 ,...,B _ij ),
The program module adds up the total amount of distortion by column for each inspection object,
(A ₁ +B ₁₂ ,A ₁ +B ₁₃ ,...A ₁ +B _1j ), (A ₂ +B ₂₂ ,A ₂ +B ₂₃ ,...A ₂ +B _2j ),..., A system for measuring the positional deviation of an inspection object on a substrate or wafer, characterized in that it calculates (A _i +B _i2 ,A _i +B _i3 ,...,A _i +B _ij ). The system according to claim 4, wherein the total amount of distortion is calculated for each row, and for this purpose, a vision camera scans the inspection objects for each row. According to claim 4, in order to measure the amount of distortion (A ₁ , A ₂ ,...A _i ) of the inspection objects belonging to row 1, the substrate or wafer is scanned by a vision camera so that row 1 is scanned in the field of view of the vision camera. A system for measuring the positional misalignment of an inspection object on a substrate or wafer, characterized in that it is scanned in a state rotated according to the field of view. According to claim 6, after measuring the amount of distortion (A ₁ , A ₂ ,...A _i ) of the inspection objects belonging to row 1, the substrate or wafer is rotated again and returned to the original position for scanning of each row. A system for measuring the positional deviation of an inspection object on a substrate or wafer. The method of claim 4, wherein the position of the substrate or wafer is aligned by verifying the positions of the first global mark, the second global mark, and the third global mark before measuring the amount of distortion of the inspection objects. A system for measuring the positional deviation of an inspection object.