JP2004132725A - Method for inspecting sputtering target - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect a bonding state between a backing plate and a target material of a sputtering target being a body to be inspected by using ultrasonic waves while preventing water sticking thereto and without damaging them. <P>SOLUTION: The method for inspecting the sputtering target, which inspects the bonding state between the target material and the backing plate by using the ultrasonic wave without submerging the sputtering target under the water, is provided with a sticking step in which a protect sheet with an adhesive layer on one side of its surface is stuck to a surface of the sputtering target, a measuring step in which a probe with an ultrasonic detector is scanned while spraying water on the stuck protect sheet and reflect echoes reflected by the bonding layer are measured, and an outputting step in which measured data are output. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for inspecting the bonding state between a target material of a sputtering target and a backing plate through a bonding layer made of a bonding material using ultrasonic waves.
[0002]
[Technical Background of the Invention]
The target used for sputtering is continuously heated by an inert gas or the like in a plasma state at the time of sputtering, whereby heat is accumulated inside the target and becomes high temperature. For this reason, generally, a backing plate made of a material having good thermal conductivity such as Cu or a Cu-based alloy is bonded to a target material via a bonding material, and the backing plate is cooled to release heat of the entire sputtering target. Like that.
[0003]
In such a case, if the bonding state of the sputtering target is not good, that is, if there is a gap between the target material and the backing plate, the target material may be separated from the backing plate during sputtering.
For this reason, when manufacturing a sputtering target, it is necessary to inspect the bonding state of the sputtering target. As such an inspection, conventionally, an inspection in which a sputtering target is scanned by immersing a sputtering target in water, specifically, a probe provided with an ultrasonic inspection element on the surface of the immersed sputtering target. Scan with, based on the transmitted wave from the ultrasonic flaw detector, to measure the presence or absence of the reflected echo after a certain time and the height of the reflected echo, to convert the height of the reflected echo into brightness or color, Inspections have been performed in which a display is displayed on a color or monochrome CRT to observe a change in reflected echo of ultrasonic waves.
[0004]
For example, as a conventional technique, in a method of inspecting a sputtering target using ultrasonic waves, a method of inspecting a sputtering target in which the thickness of a solder layer as a bonding material is 100 μm or more has been proposed. A target in which a target material is bonded on a conductive base via a solder layer is immersed in a liquid such as water (see Patent Document 1).
[0005]
However, if water is present on the surface of the target material, it is difficult to reduce the pressure when the target material is placed in a vacuum decompression device, and if the target material is metal, there is a problem that rust occurs. Is not preferred.
Therefore, after the sputtering target is immersed in water and the bonding state is inspected, it is necessary to sufficiently heat and dry the sputtering target, which is complicated and increases the number of extra steps, thereby reducing time and cost. There was a disadvantage.
[0006]
In general, for a test object that cannot be submerged, it is also performed to directly contact a probe equipped with an ultrasonic flaw detector while spraying water on the surface to inspect a bonding state. I have.
However, when the object to be inspected is a sputtering target, the surface of the sputtering target, that is, a target surface is extremely high, in order to prevent abnormal discharge such as arcing and to prevent generation of dust which causes a thin film defect. Due to the requirement for cleanliness, scratches on this target surface must be avoided.
[0007]
Therefore, when the object to be inspected is a sputtering target, an inspection method in which the ultrasonic flaw detector or a probe having the ultrasonic flaw detector directly contacts the target surface cannot be adopted.
In addition, when performing such an inspection from the backing plate side while avoiding the target surface, a cavity such as a water-cooled tube provided in the backing plate or a welded portion becomes an obstacle.
[0008]
The present inventors have conducted intensive studies in view of the above circumstances, as a result of attaching a protective sheet having an adhesive layer on one surface to the surface of a sputtering target, and spraying water over the attached protective sheet. The inventors have found that by scanning a probe provided with an ultrasonic flaw detector, the bonding state of a sputtering target can be inspected without submerging it, and the present invention has been completed.
[0009]
[Patent Document 1]
JP 2000-129434 A
[0010]
[Object of the invention]
An object of the present invention is to provide a method for inspecting a bonding state between a target material of a sputtering target and a backing plate by ultrasonic waves without attaching or damaging water to a sputtering target to be inspected. It is an object.
[0011]
Summary of the Invention
The method for inspecting a sputtering target according to the present invention is a method for inspecting a sputtering target in which a target material is bonded to a backing plate via a bonding layer made of a bonding material without submerging the sputtering target. A method for inspecting a sputtering target for inspecting with ultrasonic waves,
On the surface of the sputtering target, a sticking step of sticking a protective sheet having an adhesive layer on one side,
Spraying water on the attached protective sheet and scanning a probe equipped with an ultrasonic flaw detector, a measuring step of measuring a reflected echo reflected from the bonding layer,
An output step of outputting measured data.
It is characterized by having. In this specification, "reflection echo reflected from the bonding layer" refers to a reflection echo reflected from the interface between the target material and the bonding layer, a reflection echo reflected from the inside of the bonding layer, and a bonding layer. This is a meaning including all reflected echoes reflected from the interface with the backing plate.
[0012]
In the present invention, it is preferable that in the measurement step, the ultrasonic flaw detector is scanned while being separated from the surface of the protective sheet by at least 0.02 mm via water.
In the present invention, the thickness of the protective sheet is preferably 0.02 to 0.5 mm.
In the present invention, the probe preferably includes a plurality of ultrasonic flaw detectors. In the present invention, it is preferable that the probe includes a water supply device for spraying water on the protective sheet, and an ultrasonic flaw detector.
[0013]
In the present invention, the measuring step includes:
An input step of inputting identification information of a sputtering target to be inspected,
An extraction step of extracting a preset measurement condition from the recording device according to the input identification information,
According to the extracted measurement conditions, water is sprayed on the protective sheet, and a probe equipped with an ultrasonic flaw detector is scanned, and a scanning measurement step of measuring the reflected echo,
A preset determination area and threshold are extracted from the recording device each time measurement is performed, it is determined whether measured data exceeds the threshold in the determination area, and the measured data is displayed together with the determination result. And a data processing step of converting the data into a possible form.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described specifically.
The method for inspecting a sputtering target according to the present invention inspects the bonding state of the sputtering target by ultrasonic waves without submerging a sputtering target formed by bonding the target material to a backing plate via a bonding layer made of a bonding material. Step S10, which is a bonding step of bonding a protective sheet having an adhesive layer on one surface to the surface of the sputtering target, and spraying water on the bonded protective sheet. Step S20, which is a measuring step of measuring a reflected echo reflected from the bonding layer by scanning a probe provided with an ultrasonic flaw detector, and Step S30, which is an output step of outputting measured data, Have.
[0015]
In FIG. 1, in step S10, a protective sheet having an adhesive layer on one side is adhered to the surface of the sputtering target to protect the sputtering target, which is the inspection object, from water and scratches. Proceed to.
At this time, it is desirable to attach the protective sheet and the sputtering target so that air bubbles do not enter between them. If air bubbles exist between the protective sheet and the surface of the sputtering target, transmission of ultrasonic waves is hindered, so that it may not be possible to inspect the bonding state using ultrasonic waves. Also, when a protective sheet having no pressure-sensitive adhesive layer is used, the inspection cannot be performed for the same reason. It is considered that this is because the pressure-sensitive adhesive satisfactorily joins the protective sheet and the surface of the sputtering target and satisfactorily transmits ultrasonic waves.
[0016]
As the material of the protective sheet, a known material can be used, and it is not particularly limited. Among them, a material that does not absorb or scatter ultrasonic waves is preferable. For example, a fluororesin film; a polyester film; a polyimide film; A polyolefin film such as a polyethylene film and a polypropylene film; a PPS (polyphenylene sulfide) film; a nylon film.
[0017]
In addition, the thickness of the protective sheet, including the thickness of the pressure-sensitive adhesive layer, is generally in the range of 0.02 to 0.5 mm, preferably 0.05 to 0.2 mm. When the thickness of the protective sheet is within the above numerical range, the durability of the protective sheet is excellent and transmitted ultrasonic waves can be transmitted well.
In addition, as the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer provided on one surface of the protective sheet, known ones are mentioned, and there is no particular limitation. It is preferable that the adhesive does not remain when peeled from the target surface. Examples of such an adhesive include an acrylic adhesive, a rubber adhesive, and a silicone adhesive.
[0018]
Subsequently, in step S20, water is sprayed on the protective sheet adhered to the surface of the sputtering target in step S10, and a probe equipped with an ultrasonic flaw detector is scanned, and a reflected echo reflected from the bonding layer is reflected. Is measured, and the process proceeds to step S30.
In the present invention, specifically, for example, a probe having an ultrasonic flaw detector as shown in FIG. 3 can be used. FIG. 3 shows a bottom view of the probe. In FIG. 3, the probe 1 has an ultrasonic flaw detector 3 and a cover 5, and the cover 5 is provided with a water inlet 7. A resin part 6 made of a polymer is provided between the ultrasonic flaw detector 3 and the cover 5, and water introduced from a water inlet 7 is supplied to the resin fence 6 to the ultrasonic flaw detector 3. A concave portion 6a is provided so as to be able to be guided.
[0019]
In the present invention, it is preferable to use a probe provided with a plurality of ultrasonic flaw detectors from the viewpoint of increasing the efficiency of the inspection and shortening the inspection time.
As the ultrasonic flaw detector, a commercially available ultrasonic flaw detector can be used, but in the actual measurement step, in order to keep the oscillation intensity of the ultrasonic flaw detector used constant, before the measurement step, a standard sample is used. It is desirable to use this to correct the oscillation intensity of the ultrasonic flaw detector used.
[0020]
When scanning the probe provided with the ultrasonic flaw detector, it is preferable to scan the ultrasonic flaw detector at a distance of 0.02 mm or more from the surface of the protective sheet via water. The manner of scanning of the probe will be described with reference to FIG. In FIG. 4, the same components as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted. 4, a probe 1 represents a cross section taken along line II of the probe 1 in FIG. Using such a probe 1, a protective sheet 9 is adhered to the surface of a sputtering target formed by bonding the target material 11 to a backing plate 15 via a bonding layer 13 made of a bonding material, and then water is sprayed. The probe 1 is manually or automatically scanned so that the ultrasonic flaw detector 3 has a predetermined separation distance d while forming the water droplets 17. At this time, water droplets are introduced into the water inlet 7 of the probe 1 and pass through the concave portion of the resin portion 6 to form a water film. The water film comes into contact with the ultrasonic flaw detector 3 to generate ultrasonic waves. It plays the role of a medium for transmitting to the test object. As described above, when the distance d is 0.02 mm or more, the possibility that the ultrasonic flaw detector contacts the protection sheet is extremely low, and damage to the protection sheet and deterioration of the ultrasonic flaw detector can be prevented. The distance d is preferably 50 mm or less from the viewpoint that the ultrasonic wave can be transmitted from the ultrasonic flaw detector to the protective sheet satisfactorily.
[0021]
As described above, in the present invention, the scanning of the probe provided with the ultrasonic flaw detector can be performed manually or automatically.
When performing the scanning of the ultrasonic flaw detector manually, the separation distance d should be set to a value between 0.02 and 0.5 mm because it is possible to sense subtle warpage of the sputtering target with a sense. Can be. In this case, a portion other than the concave portion 6a of the resin portion 6 of the probe 1 comes into direct contact with the protective sheet 9, and therefore, the polymer constituting the resin portion 6 is required to have appropriate strength and elasticity. Specific examples of the polymer constituting the resin portion 6 include a nylon resin, a polyacetal resin, and a silicone resin.
[0022]
On the other hand, when scanning the ultrasonic flaw detector automatically, as described later, a separation distance d according to identification information such as the shape and warpage of the sputtering target to be measured is set in advance as a measurement condition and recorded. It can be stored in the device. From the point that the inspection can be performed by one flaw detection, the sputtering target has a shape having irregularities, and when the sputtering target also has a warp, the difference between the irregularity of the shape and the level difference of the warp is +1.0 to It is desirable to set the distance d between 10.0 mm so that the probe does not come into contact with the target to which the protective sheet is attached during scanning. When the sputtering target has any of irregularities or warpage due to the shape, the distance d is set between +1.0 to 10.0 mm with respect to the unevenness or the level of warpage, and It is desirable that the probe does not come into contact with the target to which the protective sheet is attached.
[0023]
The amount of water sprinkled on the sputtering target to which the protective sheet is attached may be any amount as long as the space between the protective sheet 9 and the ultrasonic flaw detector 3, that is, the separation distance d can be filled with water. For example, when scanning the ultrasonic flaw detector manually, if the separation distance d is 2 mm or less, water may be sprayed on a protective sheet in advance. Further, when the scanning of the ultrasonic flaw detector is performed manually, and the separation distance d exceeds 2 mm, or when the scanning of the ultrasonic flaw detector is automatically performed, the separation distance d is 1 mm. In the case where the distance exceeds d, the separation distance d can be filled with water by providing a water supply device such as a jet water flow type in the probe.
[0024]
As a probe including such a water supply device, specifically, for example, a probe including a water supply device for spraying water on the protective sheet and an ultrasonic flaw detector as shown in FIG. Can be used. In FIG. 5, the same components as those in FIG. 4 are denoted by the same reference numerals, and description thereof is omitted. In FIG. 5, a water supply device 20 is provided above the probe 21, and water is sprayed on the protection sheet 9 from the water supply device 20. In this way, the probe 21 is manually or automatically scanned so that water is sprayed and a predetermined separation distance d is set. At this time, the water sprayed from the water supply device 20 is discharged to the outside from the water inlet 7 of the probe 21 and fills the gap between the ultrasonic flaw detector 3 and the protection sheet 9, that is, the separation distance d. And serves as a medium for transmitting ultrasonic waves to the object to be inspected.
[0025]
Such an ultrasonic flaw detector is scanned while being separated from the surface of the protective sheet by the above distance via water, and a reflected echo reflected from an interface between the target material and the bonding layer is measured. In doing so, it is preferable to set appropriate measurement conditions in advance.
That is, since the sputtering target is made of various materials, even if the sputtering target has the same shape, a difference occurs in the time when the reflected echo returns and the height of the reflected echo depending on the type of the target material. In addition, even if the sputtering targets are made of the same material, the difference in the shape causes a difference in the time for returning the reflected echo and the height of the reflected echo.
[0026]
Therefore, it is necessary to change measurement conditions such as the separation distance d, the scanning speed of the ultrasonic flaw detector, the measurement frequency of the transmitted ultrasonic wave, the measurement start position, and the measurement position interval, depending on the material and shape of the sputtering target to be inspected. .
Such measurement conditions are stored in the recording device in advance in a form corresponding to the identification information of the sputtering target, and when performing an inspection, the measurement conditions are extracted from the recording device according to the input identification information, If the scanning measurement of the ultrasonic flaw detector can be automated, the inspection of the sputtering target can be performed efficiently.
[0027]
Similarly, it is necessary to change the determination region and the threshold value, which are the criteria for determining the quality of the inspection, according to the material and shape of the sputtering target. For example, when an irregularly shaped target having irregularities on its surface is measured equally under predetermined measurement conditions, the distance d between the concave and convex portions of the target is different, so that the reflected echo returns between the concave and convex portions. There is a difference in the arrival time and the height of the reflected echo. Therefore, a judgment area and a threshold value corresponding to each part of the target are set in advance, and whether or not the bonding state between the target material and the backing plate is good or bad depending on whether the measured reflected echo data exceeds the threshold value in the judgment area. Must be determined.
[0028]
Further, in a deformed target having another shape, for example, as shown in FIG. 8, in a deformed sputtering target in which a target material 41 is bonded to a backing plate 45 via a bonding layer 43 made of a bonding material, the same shape is used. Even in the case of the target, the thickness of the target material is clearly different between the portions D1 and D2. The difference in the thickness of the target material causes a difference in the time at which the reflected echo returns and the height of the reflected echo. Therefore, similarly, it is necessary to previously set a determination region and a threshold value corresponding to each part.
[0029]
Therefore, according to the measurement conditions, when measuring the reflected echo reflected from the bonding layer by scanning a probe equipped with an ultrasonic flaw detector, a determination area and a threshold, which are criteria for inspection, the identification information of the sputtering target. Is stored in the recording device in advance in a form corresponding to the above, and each time measurement is performed, a combination corresponding to the measurement position is extracted from the stored determination region and threshold value from the recording device, and data processing after measurement is performed. Can be inspected more efficiently.
[0030]
Therefore, in the present invention, the measurement step S20 is an input step of inputting the identification information of the sputtering target to be inspected, and the recording apparatus stores the measurement conditions set in advance according to the input identification information. In step S220, which is an extraction step of extracting from, and according to the extracted measurement conditions, water is sprayed on the protective sheet, and a probe having an ultrasonic flaw detector is scanned, and a scan measurement step of measuring the reflected echo is performed. A certain step S230, a predetermined determination area and a threshold are extracted from the recording device each time measurement is performed, it is determined whether or not the measured data exceeds the threshold in the determination area, and the measured data is determined. Step 240 which is a data processing step of converting the data into a displayable form together with the determination result and sending the converted data to the output step. It is preferable Ranaru.
[0031]
In FIG. 1, in step S210, identification information of a sputtering target to be inspected is input, and the process proceeds to step S220. Examples of the identification information of the sputtering target include a standard number set in association with property information such as a shape, a material, a warped state, a target material thickness, and a user name of the sputtering target. These pieces of property information are stored in the recording device in advance in association with the identification information. The storage in the recording device may be performed by directly inputting such property information.However, if there is a history measured in the past, a standard number corresponding to the property information is set at that time and stored. Can be done. In addition, in this input step, usually, a command to start measurement, designation of a data format to be output in the output step, and the like are also performed.
[0032]
In step S220, preset measurement conditions are extracted from the recording device according to the identification information input in step S210, and the process proceeds to step S230. Examples of the measurement conditions include a separation distance d, a scanning speed of the ultrasonic flaw detector, a measurement frequency of an ultrasonic wave to be transmitted, a measurement start position, and a measurement position interval. These measurement conditions are stored in a recording device in advance in a form corresponding to the identification information so that they can be extracted according to the identification information.
[0033]
In step S230, according to the extracted measurement conditions, water is sprayed on the protective sheet, and at the same time, the ultrasonic flaw detector is scanned to measure the reflected echo, and the process proceeds to step S240. At this time, every time the measurement is performed, the position information in the X-axis direction and the Y-axis direction of the location where the scanning measurement is performed is transmitted to step S240.
In step S240, a preset determination area and threshold are extracted from the recording device each time measurement is performed, it is determined whether the measured data exceeds the threshold in the determination area, and the measured data is The format is converted into a form that can be displayed together with the determination result, and the process proceeds to step S30. In step S240, the position information transmitted from step S230 is further transmitted to step S30.
[0034]
The step S240 extracts a preset determination area and a threshold value from the recording device every time measurement is performed, and determines whether or not the measured data exceeds the threshold value in the determination area, and step S241. Steps S243 and S245 indicating the judgment result of whether the bonding state of the sputtering target is good or bad in response to the result of Step S247, and Step S247 of converting the measured data into a form that can be displayed together with the judgment result. Consists of
[0035]
In FIG. 2, a step S241 extracts a preset determination area and a threshold from the recording device each time measurement is performed based on the measurement position information obtained from the step S230, and determines the measured reflected echo data. It is determined whether or not the threshold value is exceeded in the area. If the threshold value is exceeded, the process proceeds to step S245; otherwise, the process proceeds to step S243.
[0036]
In step S243, it is determined that the bonding state between the target material and the bonding layer is good, and the process proceeds to step S247.
In step S245, it is determined that the bonding state between the target material and the bonding layer is poor, and the process proceeds to step S247.
A step S247 converts the measured data into a form that can be displayed in the output step together with the result of the determination, and proceeds to a step S30. Specifically, in step S247, the reflected echo data is converted into image data or the like by known processing means in accordance with the output data format specified in step S210, and is sent to step S30, which is an output step.
[0037]
The following output step S30 is a step S310 of displaying the converted data of the measurement data and the determination result on a displayable form on a display device every time the measurement is performed, and completing the scanning of the entire sputtering target to be inspected. Step S320 of determining whether the measurement has been performed and determining whether to continue or end the measurement.
[0038]
In step S310, the data measured in step S20, subjected to luminance or color conversion together with the determination result, and converted into a displayable form is displayed on a display device such as a color or monochrome CRT, or printed out, or an external device. Then, the process proceeds to step S320.
In step S320, it is determined whether or not scanning of the entire sputtering target to be inspected has been completed, and it is determined whether to continue or end the measurement.
[0039]
Specifically, in step S320, based on the measurement position information obtained through steps S230 to S240, it is determined whether or not scanning of the entire sputtering target to be inspected has been completed. The process returns to step S230, which is a scanning measurement process, to continue the measurement. When the measurement is completed, the measurement ends.
[0040]
FIG. 6 shows an example of an automated ultrasonic inspection apparatus that can be used in the present invention. This apparatus automatically scans a probe 23 equipped with an ultrasonic flaw detector in an X-axis direction or a Y-axis direction on an object to be inspected having a protective tape adhered to the surface thereof, and detects an interface between the target material and the bonding layer. This is a device that measures the reflected echoes reflected from the device, converts the obtained reflected echo data into image data by known processing means, and displays the image data.
[0041]
In FIG. 6, an input unit 27 is for inputting identification information of a sputtering target to be inspected, a command to start measurement, and designation of an output data form as necessary.
The CPU 30 receives the identification information input by the input unit 27, extracts predetermined measurement conditions from the recording device 33 according to the identification information, and transmits the extracted measurement conditions to the driving device 25. Further, the CPU 30 receives the measured reflected echo data and the measured position information from the measuring unit 29, and extracts a predetermined determination area and threshold value from the recording device 33 from the identification information and the measured position information. It is determined whether or not the echo exceeds the threshold value in the determination area, and the reflected echo data including the determination result is subjected to luminance conversion or color conversion by a known means, and is transmitted to the output unit 31.
[0042]
The recording device 33 accumulates measurement conditions such as the separation distance d, the scanning speed of the ultrasonic flaw detector, the measurement frequency of the ultrasonic wave to be transmitted, the measurement start position, the measurement position interval, a determination area serving as a determination criterion for inspection, and a threshold. In addition, if there is a past measurement history, identification information for specifying the measured sputtering target, and its shape, material, warping state, target material thickness, user information and other property information to accumulate Things. Note that the past measurement conditions, the determination area and the threshold value used at that time, the property information, and the like are associated with the identification information, so that the information can be searched using the identification information as a keyword.
[0043]
The driving device 25 scans the probe 23 having the ultrasonic flaw detector according to the measurement conditions transmitted from the CPU 30.
The probe 23 is provided with an ultrasonic flaw detector and is for scanning while transmitting ultrasonic waves to the object to be inspected, and is electrically connected to the measuring unit 29.
The measuring unit 29 includes an ultrasonic pulsar for applying a pulse voltage to the ultrasonic flaw detector, an ultrasonic receiver for receiving and amplifying the reflected echo, setting a measurement range by the ultrasonic wave, and setting a height of the reflected echo within the range and It comprises an ultrasonic detector for measuring a path, and sends the measured reflected echo data and measurement position information to the CPU 30. In addition, an oscilloscope may be connected to the measurement unit 29 in order to observe the reflected echo.
[0044]
The threshold value and the determination region serving as the determination criterion in the method for inspecting a sputtering target according to the present invention will be described using an example in which an oscilloscope is connected to the measurement unit 29. it can.
The oscilloscope connected to the measuring unit 29 displays a continuous waveform as shown in FIG. 7 every time measurement is performed (vertical axis: intensity I, horizontal axis: time t). This continuous waveform is obtained by combining (interfering) reflected waves not only at the interface between the target material and the bonding layer but also at the interface between the bonding layer and the backing plate, inside the bonding layer, inside the backing plate, and the like. Therefore, the inspection of the bonding state between the target material and the backing plate uses the position of the reflected wave from the bonding layer.
[0045]
More specifically, when the bonding state between the target material and the backing plate is inspected by ultrasonic waves from the target side, if there is no defect inside the target material, the first wave indicates the degree of adhesion of the bonding layer. This first wave portion is used to represent.
That is, in the method of the present invention, the reflected waves from the protective sheet and the water portion are kept very low, so that the reflected waves from the bonding layer are the peaks observed first.
[0046]
The determination region J is determined from the region of the first wave so as to include the first observed peak. Note that, as described above, the time required for the reflected wave to return varies depending on the material, shape, and the like of the sputtering target to be inspected. Therefore, it is necessary to set the determination region J according to such property information.
Focusing on the waveform in the determination region J, when the bonding state between the target material and the backing plate is good, the waveform A is displayed, while when the bonding state is poor, that is, when the target material and the backing plate are When there is a gap between the two, a waveform B having a higher intensity than the waveform A is displayed. The reason why the waveform B is higher in intensity than the waveform A is that the transmitted ultrasonic wave is totally reflected by a gap between the target material and the backing plate.
[0047]
According to such a principle, the threshold value T can be empirically determined from the height of the peak observed first.
In FIG. 6, an output unit 31 receives luminance- or color-converted data from the CPU 30 and prints out a color or monochrome CRT display or these displays. When the output unit 31 is connected to another database through a network, the data can be transmitted to another database (not shown).
[0048]
【The invention's effect】
According to the present invention, the bonding state between the target material of the sputtering target and the backing plate is inspected using ultrasonic waves without adhering or damaging water to the sputtering target that is the object to be inspected. Can be.
[Brief description of the drawings]
FIG. 1 is a flowchart for explaining a sputtering target inspection method according to the present invention.
FIG. 2 is a flowchart for explaining a data processing step.
FIG. 3 is a bottom view showing an example of a probe provided with an ultrasonic flaw detector.
FIG. 4 is a schematic cross-sectional view for explaining a state of scanning of a probe.
FIG. 5 is a schematic cross-sectional view for explaining a scanning state of a probe provided with a water supply device.
FIG. 6 is a schematic explanatory view showing an example of an automated ultrasonic inspection apparatus.
FIG. 7 is a schematic diagram showing an example of a waveform of an oscilloscope.
FIG. 8 is a schematic cross-sectional view illustrating an example of a target having an irregular shape.
[Explanation of symbols]
1,23 Probe with ultrasonic flaw detector
3 Ultrasonic flaw detector
5 Cover
6 Resin section
7 Water inlet
9 Protective sheet
11,41 Target material
13,43 joining layer
15,45 backing plate
17 water
20 Water supply device
21 Probe with water supply
25 Drive
27 Input section
29 Measuring unit
30 CPU
31 Output section
33 Recording device

Claims (6)

Inspection method of a sputtering target for inspecting the bonding state between the target material and the backing plate by ultrasonic waves without submerging the sputtering target formed by bonding the target material to the backing plate via a bonding layer made of a bonding material And
On the surface of the sputtering target, a sticking step of sticking a protective sheet having an adhesive layer on one side,
Spreading water on the attached protective sheet, and scanning a probe equipped with an ultrasonic flaw detector, a measuring step of measuring a reflected echo reflected from the bonding layer,
An output step of outputting measured data. 2. The method according to claim 1, wherein in the measuring step, the ultrasonic flaw detector is scanned while being separated from a surface of the protective sheet by at least 0.02 mm via water. 3. The method for inspecting a sputtering target according to claim 1, wherein the thickness of the protective sheet is 0.02 to 0.5 mm. The method for inspecting a sputtering target according to claim 1, wherein the probe includes a plurality of ultrasonic flaw detectors. The method for inspecting a sputtering target according to claim 1, wherein the probe is provided with a water supply device for spraying water on the protective sheet and an ultrasonic flaw detector. The measuring step is
An input step of inputting identification information of a sputtering target to be inspected,
An extraction step of extracting a preset measurement condition from the recording device according to the input identification information,
According to the extracted measurement conditions, water is sprayed on the protective sheet, and a probe equipped with an ultrasonic flaw detector is scanned, and a scanning measurement step of measuring the reflected echo,
A preset determination area and threshold are extracted from the recording device each time measurement is performed, it is determined whether measured data exceeds the threshold in the determination area, and the measured data is displayed together with the determination result. 2. The method for inspecting a sputtering target according to claim 1, comprising a data processing step of converting the data into a possible form.

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