JP7438444B1 - ultrasound imaging device - Google Patents

Abstract

An object of the present invention is to provide an ultrasonic imaging device that can easily discharge fine air bubbles attached around a wafer mounted on a sample stage. SOLUTION: An ultrasonic imaging device 1 that irradiates a wafer 2 with ultrasonic waves, acquires the transmitted waves, and images them, and includes a sample stage 20 for fixing the wafer 2 in water W. has an opening 21, and the edge of the opening 21 is provided with a gripping member for gripping the wafer 2. The opening 21 is configured to be larger than the wafer 2, and the wafer 2 can be gripped by the gripping member. A gap S serving as a bubble discharge portion is formed between the outer circumference of the wafer 2 and the edge of the opening 21 . [Selection diagram] Figure 2

Description

The present invention relates to an ultrasound imaging device .

Since ultrasound has a property of being difficult to transmit through gas, ultrasound imaging devices generally use water as an ultrasound transmission medium, and perform examinations by immersing a subject and an ultrasound probe in water. At this time, if air bubbles adhere to the subject, there is a problem in that it becomes difficult to inspect the inside of the subject where the bubbles are attached. Furthermore, if air bubbles are confirmed in the test results after an ultrasonic test, there is a problem in that it is necessary to perform a re-inspection after removing the air bubbles. In order to solve these problems, the following inventions have been proposed.

For example, the ultrasonic testing apparatus shown in Patent Document 1 includes a water tank that contains water, a sample stage that is placed in the water tank, and a sample stage on which a test subject is placed, which are arranged to face each other in the vertical direction, and transmit ultrasonic waves toward the test subject. A first ultrasonic probe that emits ultrasonic waves and a second ultrasonic probe that receives ultrasonic waves that have passed through the subject, and a hydrophilic coating is formed on the lower surface of the sample stage. . Furthermore, the lower surface side of the sample table has a spouting part that spouts water.

Further, the ultrasonic inspection apparatus shown in Patent Document 2 includes an ultrasonic probe that irradiates and receives ultrasonic waves, and a sample stage on which an object to be inspected (subject) to be inspected by ultrasonic waves is placed. , a water tank that stores a liquid medium (water) in which the sample stage is immersed, and a nozzle that discharges the liquid medium to the sample stage. moves following the movement of the ultrasound probe.

Japanese Patent Application Publication No. 2014-215154 JP2019-219234A

However, the ultrasonic testing apparatuses described in Patent Documents 1 and 2 eliminate air bubbles remaining on the lower surface of a sample stage on which a subject is placed by ejecting liquid to the air bubbles. With this method, it is difficult to remove fine air bubbles that have adhered around the subject when the subject is placed on the sample stage.

The present invention solves the above-mentioned conventional problems, and aims to provide an ultrasonic imaging device that can easily discharge fine air bubbles attached around a subject mounted on a sample stage.

The present invention is an ultrasonic imaging device that irradiates an object with ultrasonic waves, acquires the transmitted waves, and visualizes the transmitted waves. The edge of the opening includes a gripping member for gripping the subject, and the opening is configured to be larger than the subject, and the gripping member grips the subject. A bubble discharge part is formed between the outer periphery of the subject and the edge of the opening.

According to the present invention, it is possible to provide an ultrasonic imaging device that can easily discharge fine air bubbles attached around a subject mounted on a sample stage.

1 is a configuration diagram showing an ultrasound imaging apparatus according to an embodiment of the present invention. 1 is a perspective view showing an ultrasound imaging device according to an embodiment of the present invention. FIG. 3 is a perspective view showing a state in which the sample stage is attached to the sample stage holder. FIG. 4 is a perspective view showing a state in which the holding member is removed from the sample stage holding section in FIG. 3; FIG. 5 is an enlarged view of the receiving member of FIG. 4; FIG. 3 is a perspective view showing a state in which the sample stage is held by the sample stage holding section. FIG. 3 is a top view showing a state in which a sample stage with a wafer attached is attached to a sample stage holding section. FIG. 7 is a top view showing a state in which the sample stage holding a wafer is being attached to the sample stage holding section.

Hereinafter, embodiments of the present invention will be described in detail using the drawings, but the present invention is not limited to the following embodiments, and various modifications and application examples may be made within the technical concept of the present invention. It is included in that scope.

FIG. 1 is a configuration diagram showing an ultrasound imaging apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view showing an ultrasound imaging apparatus according to an embodiment of the invention.
As shown in FIG. 1, the ultrasound imaging device 1 non-destructively measures the inside of a subject using ultrasound in water W as an ultrasound transmission medium, displays an exploration image of the subject, It is used to judge whether internal defects are acceptable or not.

The ultrasonic imaging device 1 is arranged in a water tank 10 and includes a sample stage 20 on which a wafer 2 (subject) is placed, a first ultrasonic probe 40 provided above the wafer 2, and a first ultrasonic probe 40 provided below the wafer 2. A second ultrasonic probe 50 is provided. The first ultrasonic probe 40 and the second ultrasonic probe 50 are arranged at opposing positions in the vertical direction (Z direction). Note that the wafer 2 is, for example, a circular thin plate that is a material for semiconductor integrated circuits.

The first ultrasonic probe 40 is a device that irradiates ultrasonic waves toward the wafer 2 (irradiation probe). The second ultrasonic probe 50 is a probe that receives ultrasonic waves transmitted through the wafer 2 (receiving probe). Note that, contrary to this embodiment, the second ultrasound probe 50 may be used as an irradiation probe, and the first ultrasound probe 40 may be used as a reception probe.

The sample stage 20 is held by a sample stage holder 30 and arranged horizontally within the water tank 10 . Note that the water in the water tank 10 is not limited to pure water, and may be tap water, and is not particularly limited. Further, the shape of the water tank 10 is not limited to the rectangular box shape as in this embodiment, but may be, for example, a cylindrical shape with a bottom. Further, the configuration and function of the sample stage 20 will be described in detail later.

The first ultrasonic probe 40 and the second ultrasonic probe 50 are arranged one above the other with the wafer 2 as the object in between, and are connected to an X-axis scanning unit (not shown). 61, a Y-axis scanning section 62 (see FIG. 2), and a Z-axis scanning section 63.

As shown in FIG. 2, the X-axis scanning unit 61 is provided above the water tank 10, and operates both the first ultrasonic probe 40 and the second ultrasonic probe 50 in the X-axis direction (horizontal direction). It is something that makes you

The Y-axis scanning units 62 are provided as a pair on both sides of the outside of the water tank 10 in the X-axis direction, and scan both the first ultrasonic probe 40 and the second ultrasonic probe 50 in the Y-axis direction (back and forth). direction).

The Z-axis scanning section 63 is attached to the X-axis scanning section 61 via a slider 65, and operates the first ultrasonic probe 40 in the Z-axis direction (vertical direction). Note that the first ultrasonic probe 40 is attached to the Z-axis scanning section 63 via a probe holder 64.

The slider 65 is provided with an arm 66 to which the second ultrasonic probe 50 is attached. The arm 66 extends downward in the Z-axis direction and extends in the Y-axis direction (horizontal direction). A second ultrasonic probe 50 is located at the tip of the arm 66 at a position facing the first ultrasonic probe 40 . Note that the second ultrasonic probe 50 is configured not to move in the Z-axis direction. In this embodiment, the second ultrasonic probe 50 is fixed in the Z-axis direction, but the second ultrasonic probe 50 is fixed in the Z-axis direction together with the first ultrasonic probe 40. It may also be configured to operate in the vertical direction.

The wafer 2 is held on a sample stage 20 and placed in water W stored in a water tank 10. Further, the first ultrasonic probe 40 is arranged above the wafer 2 in the Z-axis direction, and the second ultrasonic probe 50 is arranged below the wafer 2 in the Z-axis direction.

The sample stage 20 to which the wafer 2 is attached is held by a sample stage holder 30 that holds the sample stage 20. The sample stage holder 30 is located in the water W and is fixed to the bottom of the water tank 10 via the legs 22. Furthermore, a space is formed between the sample stage holding section 30 and the bottom surface of the water tank 10 for the second ultrasonic probe 50 to move in the X-axis direction and the Y-axis direction. Although the explanation has been given using an example in which the legs 22 are provided at the four corners of the sample stage holder 30, the present invention is not limited to this embodiment as long as the structure allows the sample stage holder 30 to be fixed to the water tank 10. do not have.

3 is a perspective view showing a state in which the sample stage is attached to the sample stage holding part, FIG. 4 is a perspective view showing a state in which the pressing member is removed from the sample stage holding part in FIG. 3, and FIG. It is an enlarged view of a receiving member. Note that each of FIGS. 3 to 5 illustrates a state in which the wafer 2 is not attached to the sample stage 20.
As shown in FIGS. 3 and 4, the sample stage 20 is a thin plate with a circular opening 21 formed therein. Further, the thickness of the sample stage 20 is such that it can ensure the rigidity to stably support the wafer 2 placed thereon, and is set, for example, to a thickness of about 2 to 10 mm. Further, as the material of the sample stage 20, a strong member such as aluminum or stainless steel is preferable. By using such a material, the first ultrasonic probe 40 and the second ultrasonic probe 50 (probe) can be made less susceptible to vibrations when they move in water W. Further, the shape of the sample stage 20 is not limited to a rectangular shape, and may be, for example, an elliptical shape.

The sample stage 20 is provided with a receiving member 71 for holding the wafer 2 in the opening 21 . Further, the sample stage 20 is provided with a holding member 72 for holding the wafer 2 at the upper edge of the opening 21 . The wafer 2 is held within the opening 21 by sandwiching the edge of the wafer 2 between the receiving member 71 and the holding member 72. At the edge of the opening 21, three pairs of a receiving member 71 and a holding member 72 (hereinafter collectively referred to as gripping members) are arranged so as to stably grip the wafer 2. The wafer 2 can be stably held if at least three gripping members are provided, but the number may be two or less or four or more depending on the size of the wafer 2.

Further, the pressing member 72 is formed in an elongated manner along the edge of the opening 21 and is arranged at a position facing the receiving member 71 in the vertical direction. Further, the holding member 72 is screwed to the edge of the opening 21 of the sample stage 20. In this embodiment, the holding member 72 is fixed at both ends in the longitudinal direction.

The sample stage holder 30 holds the sample stage 20, and includes a sample stage lower presser 31 that presses the lower side of the sample table 20, and a sample table upper side presser 32 that presses the upper side of the sample table 20. It is configured. In this way, the sample stage holding section 30 is formed in a U-shape, and holds both sides of the sample stage 20 in the X-axis direction. That is, the sample stand lower presser 31 includes a lower presser part 31a arranged along both edges of the sample table 20 in the X-axis direction, and one end of the lower presser part 31a in the Y-axis direction (the rear end part) and a connecting part 31b that connects the parts. The sample stand upper presser 32 is provided along both edges of the sample stand 20 in the X-axis direction, and is provided overlapping the lower presser portion 31a. Further, the sample stage upper presser 32 is screwed onto the lower presser portion 31a. Furthermore, a positioning member 33 is provided on the upper surface of the connecting portion 31b of the sample stage holding section 30, with which the rear end of the sample stage 20 comes into contact and determines the insertion position of the sample stage 20.

As shown in FIG. 5, the receiving member 71 is formed to protrude radially inward from the peripheral wall surface 21a of the opening 21. As shown in FIG. Further, the receiving member 71 is formed in a trapezoidal shape, and has a contact portion 71a, with which the outer periphery of the wafer 2 comes into contact, at the tip on the inner diameter side. Further, in the receiving member 71, a support portion 71b that protrudes radially inward and supports the wafer 2 is formed at the lower end of the contact portion 71a. The support portion 71b has a brim shape and is adapted to abut and support the lower surface of the edge of the wafer 2. By providing the three receiving members 71 in this manner, the wafer 2 is positioned relative to the opening 21, and a gap S (see FIG. 1) is formed between the outer periphery of the wafer 2 and the peripheral wall surface 21a of the opening 21. Ru.

FIG. 6 is a perspective view showing a state in which the sample stand is held by the sample stand holder. Note that FIG. 6 shows a state in which one side of the sample stage holder 30 in the X-axis direction is viewed from the front side in the Y-axis direction.
As shown in FIG. 6, the sample stage 20 is cut out in a concave shape except for both ends in the Y-axis direction, and held parts 20a, 20a held by the sample stage holder 30 are provided at both ends in the Y-axis direction. It is formed.

The sample stage upper presser 32 is cut out in a concave shape except for both ends in the Y-axis direction, and presser portions 32a are formed at both ends in the Y-axis direction so as to overlap the held portions 20a. A notch 32b is formed inside the holding portion 32a, through which the held portion 20a of the sample stage 20 is slidably guided. That is, the held part 20a is inserted from the front side in the Y-axis direction, and is inserted to a predetermined position in the sample stage holding part 30 while sliding. In this embodiment, only one side in the X-axis direction is illustrated and explained, but the other side is also configured in the same way.

FIG. 7 is a top view showing a state in which a sample stage with a wafer attached is attached to a sample stage holder.
As shown in FIG. 7, the diameter R1 of the opening 21 is larger than the diameter R2 of the wafer 2. As shown in FIG. As a result, a gap S (bubble discharge part) is formed in the sample stage 20 between the (edge) of the opening 21 and the outer periphery of the wafer 2 for eliminating air bubbles. This gap S is an arc-shaped hole that is formed through the opening 21 in the axial direction (perpendicular to the plane of the paper). Note that holes penetrating in the vertical direction (Z-axis direction) are closed at the positions where the receiving member 71 is provided and the position where the pressing member 72 is provided. That is, by gripping the wafer 2, the opening 21 has a gap S at the outer periphery of the wafer 2 excluding the position where the gripping member is disposed. The larger the gap S is, the easier it is to remove air bubbles, but in order to hold the wafer 2, the gripping member needs to be made larger.

Furthermore, the wafer 2 is positioned within the opening 21 by coming into contact with the contact portion 71a (see FIG. 5) of the receiving member 71, and there is a gap S between the opening 21 and the wafer 2. can be ensured. Note that the dimension of the gap S (the distance in the radial direction between the edge of the opening 21 and the outer circumference of the wafer 2) is appropriately set according to the purpose and the like within a range that does not impair the effect.

Furthermore, the wafer 2 is held down by the holding member 72 to prevent the wafer 2 from falling out of the opening 21. The holding member 72 has an elongated plate shape extending in the circumferential direction, and has a curved portion 72a shaped along the curvature of the outer periphery of the wafer 2 formed on the inside in the radial direction. Thereby, the area where the wafer 2 and the holding member 72 overlap in the Z-axis direction (perpendicular to the plane of the paper) can be reduced, and the inspection range of the wafer 2 can be expanded.

Note that the material of the receiving member 71 and the holding member 72 is not particularly limited as long as it does not damage the wafer 2, and examples thereof include resin members such as polyethylene and acrylic. Also, although not shown, by making the screw hole for fixing the holding member 72 with a screw into a long hole that is long in the direction of the wafer 2 (subject), the holding member 72 can be moved within the range of the long hole. Therefore, the work when installing the wafer 2 becomes easier.

Further, a plate spring 80 for holding the sample stand 20 is provided on the holding part 32a of the sample stand upper presser 32. By inserting the held portion 20a (see FIG. 6) of the sample stage 20 into the position of the holding portion 32a, the held portion 20a is held by the leaf spring 80. Thereby, the sample stage 20 is stably held by the sample stage holding section 30. In this embodiment, the leaf springs 80 are provided at the four corners of the sample stage 20, but as long as the plate springs 80 are configured to hold the sample stage 20, they may be provided at two locations on the front side. The number and position of the leaf springs 80 are not limited, and may be located at two locations on the back side.

FIG. 8 is a top view showing a state in which the sample stage holding a wafer is being attached to the sample stage holder.
As shown in FIG. 8, after the wafer 2 is held on the sample stand 20, the sample stand 20 is placed horizontally on the front side of the sample stand holder 30 in the Y-axis direction, and Insert the held part 20a on the back side and slide it toward the back side in the Y-axis direction. Thereby, the held part 20a is inserted while being guided toward the back side in the Y-axis direction between the lower pressing part 31a and the front pressing part 32a. After the held part 20a passes the holding part 32a, the held part 20a on the back side reaches between the lower holding part 31a and the holding part 32a on the back side in the Y-axis direction, and The held part 20a on the front side of the notification reaches the holding part 32a on the front side. By sliding and pushing the sample stage 20 further to the back from this state, all the held parts 20a at the four corners are inserted between the lower holding part 31a and the holding part 32a, and each held part 20a is inserted by the leaf spring 80. The portion 20a is held.

Next, a procedure from installing the wafer 2 on the sample stage 20 to installing the sample stage 20 on the sample stage holding section 30 will be described.
First, the wafer 2 is placed in the opening 21 of the sample stage 20. As a result, the edge of the wafer 2 is supported by the receiving member 71, and the outer circumferential surface of the wafer 2 comes into contact with the contact portion 71a, thereby forming a gap S between the outer circumference of the wafer 2 and the opening 21. In this state, the wafer 2 is positioned in the opening 21 (see FIGS. 5 and 7). Then, the holding member 72 is arranged at the edge of the opening 21 so as to overlap the edge of the wafer 2, and the holding member 72 is fixed to the sample stage 20 using screws. In this way, the wafer 2 is fixed to the sample stage 20 by the gripping members (the receiving member 71 and the holding member 72).

Then, the sample stand 20 on which the wafer 2 is fixed is immersed in water W in the water tank 10, and the sample stand 20 is tilted or the like to eliminate air bubbles stuck on the lower surface of the wafer 2. Note that if any remaining air bubbles that could not be removed even with the above procedure are confirmed, the air bubbles are removed by blowing a stream of water to the location where the air bubbles are confirmed. In particular, fine air bubbles stuck between the wafer 2 and the opening 21 are removed by the water flow through the gap S (bubble discharge section). Note that the narrower the gap S, the faster the water flow when blowing, and the wider the gap S, the slower the water flow when blowing.

Then, with the sample stand 20 holding the wafer 2 held horizontally on the front side of the sample stand holder 30, slide the sample stand 20 from the front side of the sample stand holder 30 and fit it into the sample stand. It is fixed to the holding part 30. Note that the sample stage holder 30 is fixed within the water tank 10 (see FIG. 2).

In this way, after fixing the wafer 2 to the sample stand 20 outside the water tank 10, the sample stand 20 can be placed in the water W, and then slid and fitted into the sample stand holding part 30 to be fixed. Workability when fixing the wafer 2 is improved.

Next, the operation and effect of the ultrasound imaging device 1 will be explained.
When a wafer 2 (subject) to be inspected is placed in water W, the first ultrasonic probe 40 and the second ultrasonic probe 50 are used to inspect the inside of the wafer 2. It moves horizontally with respect to the table 20 and scans over the wafer 2. Note that before the inspection, the first ultrasonic probe 40 is retracted upward away from the second ultrasonic probe 50, and when the wafer 2 is placed at a predetermined position, the first ultrasonic probe 40 The sonic probe 40 is lowered from the origin position to the focal position.

The ultrasound imaging device 1 images the strength of the received ultrasound by utilizing the property that the strength of the ultrasound after passing through the wafer 2 differs depending on the acoustic impedance of each part of the wafer 2 (subject). Thereby, the internal state of the wafer 2 can be inspected non-destructively.

Next, a method of operating the ultrasound imaging device 1 will be explained.
In order to obtain desired effects in the ultrasound imaging apparatus 1 having the bubble evacuation mechanism of this embodiment, a test operation is performed before the ultrasound imaging apparatus 1 is put into actual operation.
In this test operation, the area and shape of the opening 21 provided in the sample stage 20 are set according to the area and shape of the object (wafer 2) to be inspected. In other words, when the test object (wafer 2) is gripped by the gripping members (receiving member 71 and holding member 72), there is a gap large enough to discharge air bubbles between the test object (wafer 2) and the opening 21. The area and shape of the opening 21 are set so that S (bubble discharge part) is formed. By going through this test operation, it becomes possible to prevent bubbles from remaining around the object to be inspected (wafer 2) even in the actual operation, and it becomes possible to improve the operational efficiency.

As explained above, the ultrasonic imaging apparatus 1 of the present embodiment is an ultrasonic imaging apparatus 1 that irradiates the wafer 2 with ultrasonic waves, acquires the transmitted waves, and images the wafer 2. 2 is provided. The sample stage 20 has an opening 21, and the edge of the opening 21 is provided with a gripping member (a receiving member 71 and a holding member 72) for gripping the wafer 2. The opening 21 is configured to be larger than the wafer 2, and by gripping the wafer 2 with the gripping member, a gap S (bubble discharge portion) is formed between the outer circumference of the wafer 2 and the edge of the opening 21. According to this, fine air bubbles attached around the wafer 2 mounted on the sample stage 20 can be easily discharged from the gap S.

Furthermore, in this embodiment, the gap S (bubble discharge section) is formed at a position other than the position where the gripping member is disposed. According to this, the gripping member can be configured to stably grip the wafer 2.

Further, in this embodiment, three or more gripping members (receiving member 71 and pressing member 72) are provided, and the gripping members are arranged at equal intervals on the edge of the opening 21. According to this, the wafer 2 can be stably held on the sample stage 20.

Furthermore, in this embodiment, the gripping member is composed of a receiving member 71 arranged below the wafer 2 on which the wafer 2 is placed, and a holding member 72 arranged above the wafer 2 and holding the wafer 2. be done. According to this, the wafer 2 can be stably held on the sample stage 20 by pressing the upper and lower edges of the wafer 2.

Further, in this embodiment, the sample stage 20 is held by a sample stage holding section 30, and the sample stage holding section 30 is fixed to the water tank 10 in which the sample stage 20 is submerged. According to this, since the wafer 2 is fixed to the sample stage 20 outside the water tank 10, work efficiency is improved compared to the case where the wafer 2 is fixed inside the water tank 10.

The present invention is not limited to the above-described embodiments. For example, in this embodiment, the case where the opening 21 is circular is described as an example, but the present invention is not limited to the circular shape, and the opening 21 is not limited to the circular shape. The shape excluding the gripping member portion may bulge outward, and the shape may be such that the gap between the opening and the outer periphery of the wafer 2 is larger than in this embodiment.

1 Ultrasonic imaging device 2 Wafer (subject)
10 Water tank 20 Sample stand 21 Opening 30 Sample stand holding part 40 First ultrasonic probe 50 Second ultrasonic probe 71 Receiving member 72 Holding member S Gap (bubble discharge part)
W water

Claims (5)

An ultrasound imaging device that irradiates a subject with ultrasound, acquires the transmitted waves, and visualizes them,
comprising a sample stage for fixing the subject in water;
The sample stage has an opening,
A gripping member for gripping the subject is provided at an edge of the opening,
The opening is configured to be larger than the subject, and by gripping the subject with the gripping member, an air bubble discharge part is formed between an outer periphery of the subject and an edge of the opening. An ultrasound imaging device featuring: The ultrasound imaging device according to claim 1,
The ultrasound imaging apparatus is characterized in that the bubble discharge section is formed at a position other than a position where the gripping member is disposed. The ultrasound imaging device according to claim 1,
An ultrasound imaging apparatus characterized in that the gripping members include three or more, and the gripping members are arranged at equal intervals on the edge of the opening. The ultrasound imaging device according to claim 1,
The gripping member includes a receiving member disposed below the subject to place the subject thereon, and a holding member disposed above the subject to press the subject. Characteristic ultrasound imaging device. The ultrasound imaging device according to claim 1,
The sample stage is held by a sample stage holding part,
The ultrasound imaging apparatus is characterized in that the sample stage holding section is fixed to a water tank in which the sample stage is immersed.

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