JP7501166B2 - X-ray inspection equipment - Google Patents

Description

The present invention relates to an X-ray inspection apparatus that uses X-ray transmission or CT (Computer Tomography).

Conventionally, X-ray inspection devices that use X-ray transmission or CT have many settings for imaging conditions, making the work time-consuming. In addition, it is difficult for inexperienced users to determine the optimal condition settings.

Therefore, a technology such as that described in Patent Document 1 has been proposed for setting imaging conditions in an X-ray CT device. Here, the user is required to input simple information such as the material of the object to be inspected, such as resin, and two-dimensional indices related to image quality, such as contrast and angle of view, through an imaging condition setting screen on a monitor. Then, based on the information input by the user through this imaging condition setting screen, a preset imaging condition is selected, and a preview image corresponding to the selected imaging condition is displayed on the monitor.

Patent No. 6519663

However, in the above-mentioned technology, when the user inputs information about the imaging conditions, no reference is made to the inspection time (takt time). Inspection time is an important factor in X-ray inspection equipment. This is because, in a line configured to ship products after undergoing an inspection process using an X-ray inspection equipment, the number of products shipped per day is limited by the number of products that can be inspected per day by the X-ray inspection equipment.

The present invention was made in consideration of the above problems, and aims to provide an X-ray inspection device that can easily set imaging conditions that can obtain good image quality in an appropriate inspection time.

To solve the above problems, the present invention provides:
An X-ray inspection apparatus for inspecting an object by imaging the object using X-rays,
an inspection time condition acquisition unit that receives an input of conditions related to an inspection time;
an imaging condition storage unit that stores an imaging pattern including a plurality of imaging parameters that specify an imaging condition, the imaging pattern being associated with a condition related to the examination time;
a determination image acquisition unit that acquires a determination image for judging image quality from the X-ray image captured based on the imaging pattern associated with the input condition related to the examination time;
an image quality measuring unit that measures the image quality of the judgment image;
an image quality determination unit that determines whether or not the measured image quality of the judgment image satisfies a judgment criterion;
The image quality determination unit determines, as imaging conditions, the imaging parameters included in the imaging pattern for the X-ray image when generating the determination image determined to satisfy the determination criterion.

According to the present invention, the inspection time condition acquisition unit accepts input of conditions related to the inspection time. Then, an image for determination is acquired from an X-ray image captured based on an imaging pattern associated with the input condition related to the inspection time, and when the measured image quality of the image for determination satisfies a judgment criterion, imaging parameters included in the imaging pattern for the X-ray image when acquiring the image for determination are determined as imaging conditions. Therefore, according to the present invention, since the conditions related to the inspection time can be input, it is possible to provide an X-ray inspection device that not only obtains an image with good image quality but also allows easy setting of imaging conditions that make the inspection time appropriate.

In the present invention,
The condition relating to the inspection time may include whether the inspection time varies or does not vary.

A predetermined inspection time that serves as a reference, such as an inspection time corresponding to a preset imaging condition, is presented to the user, and the user can select whether to set imaging conditions within a range in which the inspection time varies from the predetermined inspection time, or within a range in which the inspection time does not vary. In this way, by inputting whether the inspection time varies or does not vary as a condition related to the inspection time, imaging conditions that satisfy the requirements of both a case in which the inspection time is prioritized and a case in which image quality is prioritized can be easily set. Here, when the inspection time does not vary, a variation within a range that includes a time equal to or less than the predetermined inspection time is permitted, that is, the predetermined inspection time may be considered as an upper limit, and a variation that does not exceed this upper limit may be permitted. When the inspection time varies, both a case in which the time is greater than the predetermined inspection time and a case in which the time is less than the predetermined inspection time may be permitted.

In the present invention,
The condition regarding the examination time may be to determine as the imaging condition the imaging parameter included in the imaging pattern associated with the shortest examination time among the examination times associated with the imaging patterns for the X-ray image when generating the judgment image that is judged to satisfy the judgment criterion.

In this way, it is possible to easily set the imaging conditions that satisfy the judgment criteria and that result in the shortest examination time.

The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of:
The condition regarding the inspection time may specify a time or a range as the inspection time.

In this way, the examination time is set to a specific time or range of time, and imaging conditions that provide good image quality can be easily set.

The present invention provides an X-ray inspection device that can easily set imaging conditions that provide good image quality in an appropriate inspection time.

1 is a functional block diagram of an X-ray inspection apparatus according to a first embodiment of the present invention. 5 is a flowchart illustrating a procedure of automatic imaging condition setting processing of the X- ray inspection apparatus according to the first embodiment of the present invention. FIG. 10 is a diagram illustrating an external requirement UI according to the first embodiment of the present invention. FIG. 2 is a diagram illustrating a UI according to the first embodiment of the present invention. FIG. 13 is a diagram illustrating the relationship between the number of projections and image quality. 13 is a graph showing the relationship between the number of projections and image quality.

[Application example]
Hereinafter, application examples of the present invention will be described with reference to the drawings.

First, we will explain how to set the imaging conditions in an X-ray inspection device using CT (also called an "X-ray CT device"), which is the background of the present invention.

The X-ray CT device performs reconstruction processing using multiple (for example, about 15 to 500) projection data to obtain a CT image. When CT imaging is performed using an X-ray CT device, it is not possible to confirm whether the reconstructed image is an optimal image until the CT imaging and reconstruction processing are completed. Therefore, if the CT imaging conditions are not appropriate, the CT imaging and reconstruction processing must be performed again from the beginning. Even if the CT imaging is performed again, it is not possible to know whether the re-set CT imaging conditions are optimal until the reconstructed image after the re-imaging is confirmed, and in some cases, the CT imaging must be repeated many times until the optimal reconstructed image is obtained.

Such X-ray CT devices can image a variety of materials and structures, and the required image resolution (spatial resolution and concentration resolution) and imaging time also vary, so there is a high degree of freedom in the imaging conditions, and it is necessary to set imaging conditions such as angle, tube voltage, tube current, exposure time, number of projections, and resolution, which are listed in the left column of Table 1, for each object.

The difference in image quality when the number of projections is changed among the above-mentioned imaging parameters is shown. However, the tube voltage, tube current, and exposure time are not changed, and are set to the same contrast. Figures 5(A) to 5(H) show images captured when the number of projections is set to 1, 2, 4, 8, 16, 32, 64, and 128, respectively. Figure 6 is a graph showing the relationship between the number of projections and image quality. Here, the image quality value on the vertical axis indicates a value evaluated as a percentage of the ratio of the signal level to the noise level. As can be seen from Figures 5(A) to 5(D), the image quality improves with an increase in the number of projections, but as can be seen from Figures 5(E) to 5(H), when the number of projections exceeds 16, the image quality does not improve much even if the number of projections increases. This is also clear from Figure 6, where the image quality improves exponentially with the number of projections, but the image quality tends to converge once the number of projections increases to a certain extent. On the other hand, the takt time also increases in proportion to the increase in the number of projections.

As described above, in the X-ray CT scanner, the inspection time (takt time) may vary depending on the imaging conditions.
Therefore, in the present invention, imaging conditions are set so as to achieve a good balance between optimal image quality and examination time.

Figure 1 is a functional block diagram of an X-ray inspection device 1 to which the present invention is applied, and Figure 2 is a flowchart of the automatic imaging condition setting process in the X-ray inspection device 1.

The X-ray inspection apparatus includes an external requirement UI 131. As shown in FIG. 3, the external requirement UI 131 is configured to allow the user to select and input whether the inspection time does not vary or varies. When the user selects that the inspection time does not vary (step S1), imaging patterns in which the inspection time does not vary are sequentially set among the set conditions stored in the imaging condition storage unit 114 (step S3). Then, three-dimensional data of the inspection object is reconstructed from the X-ray images captured according to each imaging condition (steps S4 and S5). The image quality of the judgment image acquired from the three-dimensional data is measured (steps S6 and S7), and it is determined whether the judgment criterion is satisfied (step S8). Then, the imaging condition corresponding to the judgment image determined to satisfy the judgment criterion is determined as the imaging condition to be used for the inspection (step S10).

In this way, the present invention makes it possible to easily set imaging conditions that provide optimal image quality within an appropriate examination time.

Example 1
Hereinafter, an X-ray inspection device 1 according to a first embodiment of the present invention will be described in more detail with reference to the drawings. However, the configuration of the device described in this embodiment should be appropriately changed depending on various conditions. In other words, it is not intended to limit the scope of the present invention to the following embodiment.

<Device Configuration>
1 is a functional block diagram showing a schematic configuration of an X-ray inspection apparatus 1. Here, an X-ray inspection apparatus that uses X-ray CT images will be described.
The X-ray inspection device 1 is an apparatus that acquires three-dimensional data by capturing images of an inspection object from a plurality of imaging positions, and is mainly configured to include an imaging unit 11, a calculation unit 12, a UI unit 13, and a bus 14. The bus 14 is a transmission path that connects each unit and transmits and receives data.

The imaging unit 11 includes an X-ray generator 111 , an X-ray detector 112 , a stage 113 , and an imaging condition storage unit 114 .
The X-ray generator 111 is a device that irradiates an object to be inspected with X-rays.
The X-ray detector 112 is a two-dimensional X-ray detector that detects the X-rays output from the X-ray generator 111 and transmitted through an object to be inspected, and generates an image. For example, an I.I. (Image Intensifier) tube or an FPD (Flat Panel Detector) can be used.
The stage 113 is a mechanism that changes the relative positions of the X-ray generator 111, the X-ray detector 112, and all or part of the object to be inspected in the X-, Y-, and Z-directions in order to image the object to be inspected from multiple imaging positions.
The imaging condition storage unit 114 is a predetermined area of a memory (for example, constituted by an auxiliary storage unit described later), and stores imaging conditions in association with the examination time when an examination was performed under the imaging conditions.

The calculation unit 12 includes a three-dimensional data creation unit 121, a Z position acquisition unit 122, an XY position acquisition unit 123, a judgment image acquisition unit 124, an image quality measurement unit 125, an image quality judgment unit 126, and an XYZ position information storage unit 127. The calculation unit 12 is a device that performs various calculations such as X-ray CT calculations and inspection processing, and may be configured with logic circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). In addition, a general-purpose calculation device called a CPU (Central Processing Unit), a main memory unit, and an auxiliary memory unit can be used. A memory such as a RAM can be used as the main memory unit. A ROM, HDD, SSD, etc. can be used as the auxiliary memory unit.

The three-dimensional data creation unit 121 is a functional unit that generates three-dimensional data from a plurality of X-ray transmission images captured by the X-ray detector 112 .
The Z position acquisition unit 122 is a functional unit that acquires the Z position of the three-dimensional data generated by the three-dimensional data creation unit 121 .
The XY position acquisition unit 123 is a functional unit that acquires the XY position of the area acquired by the Z position acquisition unit 122 from the three-dimensional data generated by the three-dimensional data creation unit 121 .
The judgment image acquisition unit 124 is a functional unit that acquires a judgment image for judging the image quality of an image of a corresponding area of the three-dimensional data created by the three-dimensional data creation unit 121 based on the XYZ position information acquired from the XYZ position information storage unit 127.
The image quality measurement unit 125 is a functional unit that measures the image quality of the determination image acquired by the determination image acquisition unit 124 .
The image quality determination section 126 is a functional section that determines whether or not the image quality of the determination image acquired by the determination image acquisition section 124 satisfies a determination criterion based on the measurement result by the image quality measurement section 125 .
The XYZ position information storage unit 127 is a specified area of a memory (for example, constituted by an auxiliary storage unit) and stores, via the UI unit 13, XYZ position information in the three-dimensional data of the object to be inspected, of an image for determining image quality.

The UI unit 13 includes an external requirement UI 131, an XYZ position UI 132, an inspection target part (area) position UI 133, and a result display UI 134. The UI unit 13 is an interface for transmitting and receiving various information between a user and the X-ray inspection apparatus, and may be displayed on a touch panel display that also serves as an input/output unit, for example, or may be displayed on an output unit such as an independently configured display and may receive input from an input unit such as a mouse or keyboard.
The external requirement UI 131 is a user interface that accepts input of conditions related to an inspection time as an external requirement, and is configured, for example, by a user interface as shown in Fig. 3. Here, the external requirement UI 131 corresponds to an inspection time condition acquisition unit of the present invention.
The XYZ position UI 132 is a user interface for inputting the XYZ position of an area to be used for image quality judgment among the three-dimensional data of the object to be inspected.
The inspection target part (area) position UI 133 is a user interface for inputting the position of a part to be inspected (inspection target part) or an area to be inspected (inspection target area) of the inspection object. Hereinafter, the inspection target part and/or the inspection target area will be abbreviated as "inspection target part (area)".
The result display UI 134 is a user interface that displays the results of the automatic setting process of the imaging conditions.

<Automatic imaging condition setting process>
Next, the procedure of the automatic imaging condition setting process will be described with reference to FIG.

Prior to the automatic setting process of the imaging conditions, windows are set for each of the parts (areas) to be inspected that are included in the captured image of the object to be inspected. When the windows are set, standard imaging conditions are also preset.

Then, by selecting one of the inspection target parts (areas) for which a window has been set and pressing the automatic setting button, the automatic setting process of the imaging conditions will start. At this time, you may also decide where to measure the image quality, which will be described later.

First, the external requirement UI 131 is displayed on the display and the user's input is accepted (step S1). At this time, for example, a dialogue as shown in FIG. 3 is displayed on the display. In addition to the display of "Automatic Adjustment" which informs the user that the imaging conditions are automatically set, two radio buttons for selecting either "Inspection time does not vary" or "Inspection time varies". When "Inspection time does not vary", an external requirement (adjustment parameter of imaging conditions) that does not vary the inspection time is set, and when "Inspection time varies", an external requirement that allows the inspection time to vary is set. At this time, the inspection time (for example, 6.0 seconds) according to the preset standard imaging conditions is displayed inside or outside the dialogue. The inspection time displayed here may be for the entire inspection area or for only the part to be inspected. Then, a "Confirm" button and a "Cancel" button are displayed on the dialogue. When the "Confirm" button is pressed, the selection by the user using the radio button is confirmed as the input. When the "Cancel" button is pressed, the selection by the user using the radio button is canceled, and the user is prompted to select the radio button again.

Next, a location for measuring image quality is set in the 3D data of the object to be inspected (step S2). This step may be omitted if it has been determined when the window is set, or if it will be set in a later step.

Next, based on the external conditions set in step S1, an imaging pattern of X-ray imaging parameters to be used in the automatic setting process of imaging conditions is set (step S3).
Table 2 shows an example of X-ray imaging parameters constituting the imaging pattern.

Here, the X-ray imaging parameters given as examples are angle, tube voltage, tube current, exposure time, number of projections, and resolution, but the X-ray imaging parameters used to automatically set the imaging conditions are not limited to these.

Of these X-ray imaging parameters, the ones that affect the takt time are the angle, exposure time, number of projections, and resolution, while the ones that do not affect the takt time are the tube voltage and tube current. Of these, changing the resolution only changes the resolution and does not affect the image quality, so the resolution is not used in automatically setting the imaging conditions. Here, the takt time is the time required to inspect an object under the set imaging conditions (inspection time).

In step S1, if "examination time does not vary" is selected as the external condition, the tube voltage and tube current are used as X-ray imaging parameters to set an imaging pattern for automatically setting the imaging conditions.
Furthermore, in step S1, if "examination time varies" is selected as the external condition, the angle, tube voltage, tube current, exposure time, and number of projections are used as X-ray imaging parameters to set an imaging pattern for automatically setting the imaging conditions.
The imaging patterns for automatically setting the imaging conditions are not limited to these.

Next, the processes from step S4 to step S9 described later are repeated for all imaging patterns (loop L1). At this time, when repeating imaging for all imaging patterns, the priority order in which the multiple imaging parameters included in the imaging patterns are changed can be set appropriately, but if "examination time varies" is selected in step S1, the values may be changed in the following order: angle, tube voltage, and tube current.

For one imaging pattern, first, the X-ray generator 111 and the X-ray detector 112 are controlled to perform X-ray imaging of the inspection object (step S4).

Next, the three-dimensional data creation unit 121 creates three-dimensional data based on the X-ray image captured in step S4 (step S5).

Next, the judgment image acquisition unit 124 acquires the XYZ position that specifies the slice for measuring the image quality set in step S2 from the XYZ position information storage unit 127, and extracts the image quality judgment image corresponding to the XYZ position (step S6). If the XYZ position that specifies the place for measuring the image quality is not set in step S2, it may be set in this process .

Next, the image quality measurement unit 125 measures the image quality (step S7). The method for measuring the image quality is not particularly limited, but an appropriate method such as the signal-to-noise ratio, the mean square error (MSE), the detail variance and the background variance, etc. may be adopted. The window set prior to the automatic setting process may be used to measure the image quality.

Next, the image quality determination unit 126 determines whether the image quality measurement result in step S7 satisfies the internally set image quality determination criteria (step S8).

In step S8, if the image quality satisfies the judgment criteria, the process proceeds to step S10. In step S10, the image quality judgment unit 126 determines that the imaging conditions for the imaging judged to satisfy the criteria in step S8 are the imaging conditions to be set. The imaging conditions determined in step S10 and the examination time under the imaging conditions are displayed on the display in the form of a result display UI 134 such as a dialogue (step S11), and the imaging conditions and examination time at that time are set, and the automatic setting process ends.
If the image quality does not satisfy the standard in step S8, the process proceeds to the next imaging pattern (step S9), and specifically, the process following X-ray imaging (step S4) is repeated.

If the image quality does not meet the criteria in step S8 for all imaging patterns, the image quality determination unit 126 displays a dialog like that shown in FIG. 4 on the display to inform the user of this (step S12). Here, an "OK" button is displayed along with a message saying "Although the criteria were not met, the imaging conditions with the best image quality will be set." If the user presses the "OK" button, the imaging conditions with the best image quality are determined to be the imaging conditions to be set (step S13), and the same process as step S11 is performed. If a predetermined time has passed without the user pressing the "OK" button, the automatic setting process is terminated.

If the field of view includes multiple parts (areas) to be inspected, the imaging conditions are automatically set for the other parts (areas) to be inspected in the same way.

In this way, with the X-ray inspection device 1 according to this embodiment, it is possible to easily set imaging conditions that provide optimal image quality within an appropriate inspection time.

[Modifications]
In the above-mentioned first embodiment, the external requirement UI 131 allows the user to select and input whether the inspection time varies or does not vary with respect to the inspection time. Conditions related to the inspection time that can be input by the external requirement UI 131 are not limited to this. For example, when there are multiple imaging conditions that satisfy the judgment criterion, the imaging condition that results in the shortest inspection time may be determined as the imaging condition to be used for the inspection. Also, it may be possible to input a condition that results in the inspection time being a specific time or within a specific time range. In this way, imaging conditions that can obtain good image quality with an inspection time that meets the user's desire can be easily set.

In the following, the components of the present invention will be described with reference to the reference numerals in the drawings in order to make it possible to compare the components of the present invention with the configurations of the embodiments.
<Invention 1>
An X-ray inspection device (1) for inspecting an object by imaging it using X-rays,
an inspection time condition acquisition unit (131) that receives input of conditions related to an inspection time;
an imaging condition storage unit (11 4 ) that stores an imaging pattern including a plurality of imaging parameters that specify an imaging condition, the imaging pattern being associated with a condition related to the examination time;
a judgment image acquisition unit (12 4 ) that acquires a judgment image for judging image quality from the X-ray image captured based on the imaging pattern associated with the input condition related to the examination time;
An image quality measurement unit (12 5 ) that measures the image quality of the judgment image;
an image quality determination unit (127) that determines whether or not the measured image quality of the determination image satisfies a determination criterion;
Equipped with
The X-ray inspection device (1), characterized in that the image quality judgment unit ( 126 ) determines the imaging parameters included in the imaging pattern for the X-ray image when acquiring the judgment image judged to satisfy the judgment criterion as the imaging conditions.

1: X-ray inspection device 114: Imaging condition storage unit 124: Determination image acquisition unit 125: Image quality measurement unit 126: Image quality determination unit 131: External requirement UI

Claims (4)

An X-ray inspection apparatus for inspecting an object by imaging the object using X-rays,
an inspection time condition acquisition unit that receives input from a user of conditions related to an inspection time , which is a time required to inspect the object under predetermined imaging conditions, including a time for capturing an X-ray image of the object;
an imaging condition storage unit that stores an imaging pattern including a plurality of imaging parameters that specify the imaging condition, the imaging pattern being associated with a condition related to the examination time;
a determination image acquisition unit that acquires a determination image for judging image quality from the X-ray image captured based on the imaging pattern associated with the input condition related to the examination time;
an image quality measuring unit that measures the image quality of the judgment image;
an image quality determination unit that determines whether or not the measured image quality of the judgment image satisfies a judgment criterion;
The X-ray inspection apparatus is characterized in that the image quality judgment unit determines the imaging parameters included in the imaging pattern for the X-ray image when acquiring the judgment image that is judged to satisfy the judgment criterion as the imaging conditions. 2 . The X-ray inspection apparatus according to claim 1 , wherein the condition regarding the inspection time includes whether the inspection time varies or does not vary with respect to the predetermined inspection time presented to the user . 2. The X-ray inspection apparatus according to claim 1, wherein the condition regarding the inspection time is determined to be the imaging condition based on the imaging parameter included in the imaging pattern associated with the shortest inspection time among the inspection times associated with the imaging patterns for the X-ray image when generating the judgment image that is judged to satisfy the judgment criterion. The X-ray inspection device according to claim 1, wherein the condition regarding the inspection time is to specify a time or a range as the inspection time.

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