KR102679092B1 - Ct device with improved precision for semiconductor inspection - Google Patents

Abstract

The present invention relates to an oblique CT equipment capable of accurately adjusting the origin during relative movement of the components constituting the CT device, including an X-ray tube, a detector transported at an angle with respect to the central axis of the beam area from the , a stage that rotates the object to be inspected within the beam area, and a transfer system that can adjust the origin by gradually changing the vertical and horizontal positions of the stage and the object to be inspected in the process of changing the top position of the detector to the oblique position. A CT device including:

Description

CT device with the function of improving the precision of semiconductor inspection {CT DEVICE WITH IMPROVED PRECISION FOR SEMICONDUCTOR INSPECTION}

The present invention relates to CT examination technology, and more specifically, to CT equipment capable of resetting the origin when the components constituting the CT device are relatively moved to form a tilt angle.

A CT (Computed Tomography) device rotates an output source of radiation such as It refers to a device that is acquired and is currently being distributed to various industries.

These CT devices have the advantage of being able to determine defects without cutting or disassembling the test object. CT equipment mainly used for medical purposes fixes the test object and rotates the imaging device to take It is a device that obtains images.

Due to the advantage of being able to destroy the inside of an object to be inspected in a non-destructive manner, CT devices are being applied to a wide range of industrial fields, and numerous research and development efforts are being conducted to suit the special characteristics of each field. A representative industrial field is the semiconductor field, where semiconductor chips are stacked and designed through packaging techniques, which is the only way to increase the directness of semiconductors. Such packaging is inspected using X-ray inspection to check for cracks in the chip or the connection between chips. At this time, the use of 3D tomography is essential due to the complex structure of the packaged chip. In other words, the development of chips with improved integration must be accompanied by the development of more precise and applicable CT inspection equipment.

Previously, the object was only inspected through simple 2D image acquisition, but the demand for 3D inspection to understand three-dimensional changes is increasing.

In recent years, it has been difficult to inspect objects that are small in size or have a wide shape in the conventional method in which the imaging equipment is fixed, so based on this, improvements have been made to perform imaging by rotating the imaging equipment within a certain angle around the object to be inspected. Research on Oblique-CT is also steadily increasing.

General industrial 3D oblique CT equipment is not limited by the type or size of the object to be inspected and can check the internal structure without disassembly, so it can be widely used to identify internal damage or defects.

Typical industrial oblique CT equipment performs the examination by rotating the rotary table in one or two directions when performing the examination, and is configured with an X-ray tube located at the bottom of the rotary table and a detector located at the top. At this time, while the position of the X-ray tube is fixed, the detector is rotated at a predetermined angle to obtain multi-angle images of the subject.

Recent related research includes the development of improvements in inspection speed, and by developing an algorithm that shortens the time to reconstruct 2D information into 3D images, equipment that can be used in actual industrial sites beyond simple research and analysis is being developed. In addition, research is being actively conducted on not only inspection speed but also high-magnification precision image acquisition, and for this purpose, there is a trend to develop structures or systems that reduce vibration occurring during inspection.

One of the limitations pointed out in the oblique CT is the problem of magnification, because the magnification is determined in proportion to the distance between the X-ray tube and the object to be examined. As a result of some research, there are cases where the positions of the X-ray tube and detector are replaced. The technology below presents a technology that applies this concept.

Korean Patent Publication No. 10-2018-0080780 discloses a conventional oblique CT equipment, and Figure 1 is a front view of it.

Looking at the above technology, the X-ray tube (1) is positioned at the top to change the distance between the In addition, this X-ray tube (1) and the table on which the subject is placed are structurally separated, so we proposed a structure in which the vibration of the motor (2) used to rotate the X-ray tube or the table cannot affect each other. . Accordingly, the detector 3 is placed at the bottom of the table.

This technology allows the magnification to be adjusted because a high-magnification image can be obtained by bringing the X-ray tube as close to the subject as possible. However, in this case, there is an advantage over conventional oblique CT equipment in obtaining magnification, but problems with FOV arise. There are attempts to solve this problem through focus control or software, but the technical difficulty is high.

Meanwhile, securing the center of rotation is pointed out as another problem with conventional oblique CT equipment. In the case of oblique CT, since two or more elements must inevitably be rotated and transferred, a problem occurred in which the origin of rotation continuously changes during the relative transfer process. In recent years, as resolution has increased and parts have become more precise, this change in origin has a significant impact on the reliability of inspection.

To solve this problem, the operator had to check the rotation image directly to determine the concentricity and then proceed with the scan again, which not only resulted in time and manpower loss, but also had limitations in ensuring accuracy.

Recognizing these problems, the present invention was derived through the following research and development.

This patented invention is the result of research (AICT-04-TB1) conducted with the support of the “Gyeonggi-do Test Bed Utilization Semiconductor Technology Development Project” managed by the Next Generation Convergence Technology Research Institute with financial resources from Gyeonggi-do in 2023.

The present invention was developed to solve the above problems, and is capable of adapting to changes in the origin due to the movement of the configuration in conventional CT equipment, and can reduce the burden on the equipment as well as improve the reliability of inspection. The purpose is to provide a CT device with the function of improving the precision of examination.

The present invention includes an X-ray tube 100 that emits A stage 300 in which a tube is placed at the bottom, a detector is placed at the top, and an object to be inspected is placed at the top, a vertical transfer unit 340 that raises and lowers the object to be inspected, and a horizontal device that adjusts the horizontal position of the object to be inspected. A CT device that includes a transfer unit 330 and has a function of improving the precision of semiconductor inspection is provided.

The vertical transfer unit transfers the focus point 1001 of the object to be inspected, which is set based on the top position, in the vertical direction while the detector is located at a random angle (A) set to be closer to the axis than the tilt position, It can be transferred to a vertical transfer point (1001v) that has a rotation center and focus corresponding to the angle.

The horizontal transfer unit can set the oblique origin by transferring the focus point transferred to the vertical transfer point in the horizontal direction to the origin transfer point (1001h) while the detector is placed in the oblique position.

Additionally, it may include a transfer path 320 that guides the detector to move in an arc direction.

According to one embodiment, the arbitrary angle is determined between the normal direction forming the axis and the tilt position, and the position of the origin can be adjusted in conjunction with the transfer process along the transfer path 320 of the detector 200.

By the configuration of the present invention described above, the conventional method of ignoring or adjusting the minute error caused by the tilt angle of the detector during oblique CT inspection or adjusting it by an algorithm is improved, and the object to be inspected is directly transferred to the z-axis and located at the origin. Because adjustment is possible, the convenience, speed, and economic efficiency of management are improved when changing the inspection mode.

In addition, since accuracy is dramatically higher than the manual setting process and automated origin setting is possible, time and manpower can be saved, which has the effect of dramatically improving productivity.

Figure 1 is a front view of a conventional oblique CT equipment.
Figure 2 is a front view of a CT device having a function of improving the precision of semiconductor inspection according to the basic concept of the present invention.
Figure 3 is a conceptual diagram for explaining changes in directionality and origin at the top position and oblique position.
FIG. 4 is a conceptual diagram illustrating the process in which the stage is transferred to adapt to changes in the origin in the CT device with the function of improving the precision of semiconductor inspection according to the present invention.
Figure 5 is a diagram for explaining an

Hereinafter, a CT device having a function of improving the precision of semiconductor inspection according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

However, the embodiments described below are merely intended to provide a detailed description so that a person skilled in the art can easily implement the invention, and this does not limit the scope of protection of the present invention. doesn't mean

In the following description, when a part is said to be 'connected' to another part, this includes not only the case where it is directly connected, but also the case where it is connected with another element or device in between. In addition, when a part is said to 'include' a certain component, this does not mean excluding other components, but may include other components, unless specifically stated to the contrary.

The present invention basically includes an X-ray tube, a detector transported at an angle to the central axis of the beam area from the A CT device including a transfer system that can adjust the origin by changing the vertical and horizontal positions of the stage and the object to be inspected in the process of changing the position is provided.

In the description of the present invention, the object to be inspected that is the subject of

Figure 2 is a front view of a CT device having a function of improving the precision of semiconductor inspection according to the basic concept of the present invention.

The present invention basically targets equipment that can inspect defects, etc. by photographing an inspection object (1000) and analyzing the image by applying the principles of a known CT device. The X-ray tube (100) and the inspection object (1000) The inspection mode can be changed by moving the detector 200 between a top position that is in series with and an oblique position that has a predetermined inclination.

An object to be inspected (1000) is placed on the stage (300), and an axis line ( It is configured to include a detector 200 that can change direction to a normal direction with the horizontal surface with which T) is matched and to a tilt position (O) inclined with respect to the axis (T).

The X-ray tube 100 may be an X-ray tube with an electron gun and a target inside, and the type is not limited as long as it is a device that emits X-rays. When an X-ray is output from the

A predetermined beam area emitted from the X-ray tube 100 may have a cone shape that spreads as it progresses toward the inspection object 1000 and the detector 200. Here, the axis (T) and tilt position (O) may be understood to mean the direction in which the detector 200 faces the object 1000 to be inspected.

When the detector 200 is placed on the axis T, a predetermined 2D image can be acquired in the normal direction, and the detector 200 is transported along the transfer path 320 to obtain a predetermined image with respect to the axis T. When placed in the tilt position (O) by forming a tilt angle of , 3D scanning is possible when the inspection object 1000 is rotated.

The detector 200 can be moved within a predetermined beam area and performs a function of generating an image by detecting X-rays that have passed through the inspection object 1000. The detector 200 may use known X-ray detection means. In the description of the present invention, tilt means having a predetermined inclination on the axis T. In the illustrated embodiment, the tilt direction of the detector 200 is left and right, but this directionality is not limited. In some cases, it may also be considered that the coordinates are changed from the positions shown for the entire X-Y-Z axis.

A transfer path 320 is formed to transport the detector 200, and the transport path 320 may be formed in an arc shape capable of capturing the position of the object 1000 to be inspected. For example, a portion of the transfer path 320 may correspond to the axis T. As for the transfer path 320, various known transfer means such as rails, robot arms, link bars, etc. may be considered.

As shown, the detector 200 is configured to be tiltable with respect to the axis T from the there is.

In order to rotate the inspection object 1000, a stage 300 capable of rotation control while the inspection object 1000 is seated may be configured. The schematic diagram for the rotation of the stage 300 will be omitted. Additionally, this stage 300 may include a known table or tray.

In this way, the detector 200 is tilted on the stage 300 and the inspection object 1000 is rotated to obtain a 3D image while filming. The inspection object 1000 has a predetermined volume and shape and is connected to the detector 200. The center of rotation and focus change depending on the tilt angle.

In this way, when the detector 200 is transferred from the axis (T) and placed in the tilt position (O), in order to align the changing origin, in the case of the prior art, the 360° rotation image is directly checked to check the concentricity and the inspection object (1000) The origin was adjusted by moving the back. However, this origin adjustment method requires excessive effort and time, and is inefficient as it requires repeated work to reduce errors.

In the present invention, in order to solve the above problem, when the detector 200 is transferred through the transfer path 320 and converted to the so-called oblique mode to form a predetermined tilt angle, the inspection object 1000 is linked to this. Raising and lowering and horizontal transfer were carried out.

A vertical transfer unit 340 was configured to control the height of the stage 300 on which the inspection object 1000 is mounted. The vertical transfer unit 340 may be a known transfer device such as a ball nut, shaft, gear, belt, link, rail, arm, etc.

This raising and lowering unit 340 can raise and lower the stage 300 in conjunction with the transfer of the detector 200, more precisely, the formation of a tilt angle, in the transfer path 320 having a tilt driving unit.

Additionally, the horizontal transfer unit 330 may be configured to transfer on the X-Y plane of the stage 300 to adjust the origin. The horizontal transfer unit 330 may use known transfer devices such as ball nuts, shafts, gears, belts, links, rails, and arms to transfer the stage 300 back and forth and/or left and right.

Adjustment of the FOV will be possible through the linked operation of the vertical transfer unit 340 and the horizontal transfer unit 330, and embodiments related to this operation sequence will be described later.

Transport control of the stage 300 may be performed by a predetermined control unit (not shown), and a predetermined artificial intelligence algorithm may be provided to automatically adjust the origin.

Figure 3 is a conceptual diagram to explain the change in directionality and origin at the top and oblique positions in the CT device with the function of improving the precision of semiconductor inspection of the present invention, and Figure 4 is a diagram showing the This is a conceptual diagram to explain the process.

Referring to FIG. 2, an inspection object 1000 is placed on a stage 300, and an X-ray tube 100 is disposed at the bottom thereof. The state in which the detector 200 is placed in the normal direction of the stage 300, that is, on the axis T, is defined as the top position 210T. At the top position 210T, an X-ray image of the object 1000 to be inspected at a predetermined focus point 1001 will be generated. This inspection mode is defined as top mode.

As described above, if the detector 200 is transported along the transport path 320 and placed in the tilt position (O), it operates in the oblique mode, and therefore the detector 200 is placed in the oblique position (210o). When aiming at the focus point 1001 from the oblique position 210o, it can be seen that the angle and distance to the beam change.

The focus point 1001 represents the rotation center and/or focus of the inspection object 1000 set at the top position 210T. In addition, the top position (210T) and the oblique position (210o) will be understood as substantially meaning an imaginary line connecting the focus point 1001 or the changed focus point and the point where the image is sensed in the detector 200. You can.

In the case of semiconductors, they are small and have a small thickness, but when magnification is increased for precise inspection, a change in the origin is inevitable when operating in the oblique mode.

Figure 4 shows only the focus points for convenience of understanding, excluding the elements constituting the inspection object 1000 and the stage.

The illustrated axis T is set as the z-axis, and the horizontal axis of the focus point 1001 when placed on the axis T is set as the y-axis.

If the magnification is large or the position of the origin has a predetermined eccentric position with respect to rotation, the process of moving the focus point 1001 from the axis T to the tilt position O is quite difficult and requires a lot of time and manpower. Waste is also inevitable.

The present invention proposes a method to make this process as efficient as possible.

Figure 4(a) shows the process in which the focus point 1001 is transported in the vertical direction. As described above, the positional transfer in the vertical direction can be performed by the vertical transfer unit 340.

According to the concept of the present invention, the first transfer is performed by setting a random angle (A) so that the detector 200 is placed closer to the axis than the tilt position (O). Based on this random angle (A), the focus point (1001) is transferred to the vertical transfer point (1001v) so that it has a rotation center and focus corresponding to the tilt angle of the detector. The arbitrary angle (A) is a preset angle between greater than 0 degrees, which is the position of the axis T, and less than the tilt angle of the tilt position (O).

Since the arbitrary angle (A) is closer to the axis (T) than the tilt position (O), focus adjustment is meaningful only by the vertical position.

As described above, a standard for horizontal transfer can be established based on the vertical transfer point (1001v) vertically transferred at an arbitrary angle (A).

Figure 4(b) shows the process of transferring in the horizontal direction with respect to the vertical transfer point (1001v).

With the focus point 1001 initially transferred to the vertical transfer point 1001v having a rotation center and focus corresponding to the tilt angle with respect to the detector 200 placed at the random angle A, as follows: Secondary transfer takes place.

The secondary transfer is provided so that the detector 200 is first placed with respect to the tilt position (O) and operated in an oblique mode.

In addition, the inspection object 1000 is transferred by the horizontal transfer unit 330 based on the detector 200 placed at the oblique position 210o, and the transfer to the origin transfer point 1001h is completed in this way. . In the process of transferring the origin to the transfer point 1001h, the focus of the X-ray image can be finally aligned.

In some cases, it may be considered to transfer the horizontal and vertical positions at the same time with the oblique position (210o) determined, but in this case, the range of choices is large, resulting in time loss and optimization problems. Additionally, if the horizontal position is transferred first and then the vertical position is adjusted, accurate control of the rotation origin may be difficult and readjustment may be necessary.

Note that in the present invention, in order to solve all of these problems, the vertical position is first set at an arbitrary angle, and secondarily, the horizontal position is finally adjusted at the oblique position to determine the origin transfer point (1001h).

Meanwhile, when changing from the oblique mode to the top mode, the process can be done in the reverse order as above, and overlapping explanations will be omitted.

As described above, the origin, which is changed by tilt when the detector 200 operates in a predetermined inspection mode, can improve control efficiency and accuracy by sequentially controlling the vertical and horizontal positions of the inspection object 1000 on the stage 300. There is.

Meanwhile, for example, when inspecting by dividing the area of the inspection object 1000 having a predetermined area, the horizontal transfer unit 330 operates to transport the inspection object 1000 in the detection area of the detector 200. You will be able to. In this case as well, the origin changes and the vertical transfer unit 340 can function to correct the origin.

In addition, it may be considered that the horizontal transfer unit 330 operates to change the position of the focus or origin that changes depending on the height when selecting a predetermined height direction layer.

Figure 5 is a diagram for explaining an X-ray image when operating in oblique mode according to the above example.

The X-ray image 1010 may be image data generated by the detector 200 or an image of the inspection object 1000 implemented on the display.

At the top position (210T), an image of the object to be inspected is expressed corresponding to the focus point (1001), which is displayed as a solid line.

The state in which the initial focus point is changed to a vertical transfer point (1001v) and an origin transfer point (1001h) by the vertical transfer unit 340 and the horizontal transfer unit 330 is expressed as a dotted line.

In this way, by adjusting the height and horizontal position of the inspected object 1000, it is possible to accurately set the transfer position from the central intersection point (reference number not shown), which means the axis T of the inspected object 1000.

As described above, the height of the vertical transfer unit 340 is adjusted by a predetermined control unit, and the tilt position (O) and arbitrary angle corresponding to the oblique position (210o) of the detector 200 in the transfer path 320 Since (A) is preset, there may be differences in the position values adjusted depending on the arrangement and/or size and/or shape of the inspection object 1000. According to a preferred embodiment, the height (v) and horizontal (h) transport may be automatically adjusted in conjunction with the tilt of the detector 200 according to a preset value according to the type of the object 1000 to be inspected. When moving to the above set value, it is efficient to perform the origin setting operation in conjunction with the tilt operation process.

In addition, a case where the height and horizontal position of the inspected object 1000 are set through an artificial intelligence learning process may be considered.

In an additional embodiment, by driving the horizontal transfer unit 330 and/or the vertical transfer unit 340, a 3D image suitable for focus may be obtained by arbitrarily selecting a layer whose height is desired to be detected.

By using the above-described CT device with the function of improving the precision of semiconductor inspection of the present invention, the conventional method of ignoring minute errors caused by the tilt angle of the detector during CT inspection or adjusting it by an algorithm has been improved, Since it is possible to transport the inspected object and adjust the origin, the convenience, speed, and economic efficiency of management are improved when changing the inspection mode.

In addition, since accuracy is dramatically higher than the manual setting process and automated origin setting is possible, time and manpower can be saved, which has the effect of dramatically improving productivity.

In the above, the present invention has been described in detail based on examples and accompanying drawings. However, the scope of the present invention is not limited by the above embodiments and drawings, and the scope of the present invention will be limited only by the content described in the claims described later.

100...X-ray tube 200...detector
210o...oblique position 210T...top position
300...stage 320...transfer path
330...Horizontal transfer unit 340...Vertical transfer unit
1000...test object 1001...focus point
1001v...vertical transfer point 1001h...origin transfer point
1010...X-ray image

Claims (3)

X-ray tube 100 that emits X-rays;
A detector 200 that can be transferred from a top position 210T corresponding to the axis T from the X-ray tube to an oblique position 210o having a tilt position O;
A stage 300 on which the X-ray tube is placed on the lower side, the detector is placed on the upper side, and the object to be inspected is placed on the upper side;
A vertical transfer unit 340 that raises and lowers the inspection object;
It includes a horizontal transfer unit 330 that adjusts the horizontal position of the object to be inspected,
The vertical transfer unit,
The focus point (1001) of the object to be inspected, which is set based on the top position, is moved vertically while the detector is located at a random angle (A) set to be closer to the axis than the tilt position, and the rotation center corresponding to the angle of the detector is set. and transferred to a vertical transfer point (1001v) having a focus,
The horizontal transfer unit,
A CT device that sets the oblique origin by transferring the focus point transferred to the vertical transfer point in the horizontal direction with the detector placed in the oblique position and transferring it to the origin transfer point (1001h).
According to paragraph 1,
A CT device including a transfer path 320 that guides the detector to move in an arc direction.
According to paragraph 2,
The arbitrary angle is,
A CT device that is set between the normal direction that forms the axis and the tilt position that determines the oblique position.

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