Ultrasonic imaging device

Abstract

To provide an ultrasonic imaging device capable of simply discharging fine bubbles adhering to the periphery of a wafer installed on a sample stage.SOLUTION: An ultrasonic imaging device 1 irradiates a wafer 2 with ultrasonic waves, and acquires and visualizes transmitted waves. The ultrasonic imaging device comprises a sample stage 20 for fixing the wafer 2 in water W. The sample stage 20 has an opening part 21. An edge part of the opening part 21 comprises a gripping member for gripping the wafer 2. The opening part 21 is configured to be larger than the wafer 2. By gripping the wafer 2 with the gripping member, a gap S, which serves as a bubble discharge part, is formed between an outer peripheral part of the wafer 2 and the edge part of the opening part 21.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an ultrasound imaging device and an operating method thereof. [Background technology]

[0002] Since ultrasonic waves are difficult to transmit through gas, ultrasonic imaging devices generally use water as an ultrasonic transmission medium, and the test object and ultrasonic probe are immersed in water for inspection. In this case, if air bubbles adhere to the test object, it becomes difficult to inspect the inside of the test object where the air bubbles are attached. In addition, if air bubbles are found in the inspection results after ultrasonic inspection, it is necessary to remove the air bubbles and then perform the inspection again. In order to solve these problems, the following inventions have been proposed.

[0003] For example, the ultrasonic inspection device shown in Patent Document 1 has a water tank for storing water, a sample stage placed in the water tank and on which a test object is placed, a first ultrasonic probe for irradiating ultrasonic waves toward the test object and a second ultrasonic probe for receiving ultrasonic waves transmitted through the test object, which are arranged opposite each other in the vertical direction, and a hydrophilic coating is formed on the underside of the sample stage. Furthermore, the underside of the sample stage has a jetting part for jetting water.

[0004] Furthermore, the ultrasonic inspection device shown in Patent Document 2 has an ultrasonic probe that irradiates and receives ultrasonic waves, a sample stage on which an object to be inspected (specimen) to be inspected using ultrasonic waves is placed, a water tank that stores a liquid medium (water) in which the sample stage is immersed, and a nozzle that ejects the liquid medium into the sample stage, and the ultrasonic probe moves within the inspection range and the nozzle moves following the movement of the ultrasonic probe. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-215154 A [Patent Document 2] JP 2019-219234 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the ultrasonic inspection devices described in Patent Documents 1 and 2 eject liquid from the bottom surface of the sample stage on which the test object is placed to remove the remaining air bubbles. With this method, it is difficult to remove fine air bubbles that have adhered to the periphery of the test object when the test object is placed on the sample stage.

[0007] SUMMARY OF THE PRESENT INVETION The present invention has been made to solve the above-mentioned problems of the prior art, and has an object to provide an ultrasonic imaging apparatus capable of easily discharging fine air bubbles adhering to the periphery of a subject placed on a sample stage. [Means for solving the problem]

[0008] The present invention is an ultrasound imaging device that irradiates an ultrasound wave to a test subject and acquires and visualizes the transmitted wave, and is characterized in that it includes a sample stage for fixing the test subject in water, the sample stage having an opening, and a gripping member for gripping the test subject at the edge of the opening, the opening being larger than the test subject, and by gripping the test subject with the gripping member, a bubble discharge portion is formed between the outer periphery of the test subject and the edge of the opening. Effect of the Invention

[0009] According to the present invention, it is possible to provide an ultrasonic imaging device that can easily remove fine air bubbles that have adhered to the periphery of a subject placed on a sample stage. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing an ultrasound imaging device according to an embodiment of the present invention; [Diagram 2] 1 is a perspective view showing an ultrasonic imaging device according to an embodiment of the present invention; [Diagram 3] FIG. 2 is a perspective view showing a state in which the sample stage is attached to a sample stage holder. [Figure 4] 4 is a perspective view showing a state in which a pressing member is removed from the sample stage holding part in FIG. 3. FIG. [Diagram 5] 5 is an enlarged view of the receiving member of FIG. 4. [Figure 6] FIG. 2 is a perspective view showing a state in which the sample stage is held by the sample stage holding part. [Figure 7] FIG. 2 is a top view showing a state in which the sample stage on which the wafer is attached is attached to a sample stage holder. [Figure 8] 13 is a top view showing a state in which the sample stage holding the wafer is being mounted on the sample stage holder. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiment, and various modifications and application examples within the technical concept of the present invention are also included in its scope.

[0012] FIG. 1 is a block diagram showing an ultrasonic imaging device according to an embodiment of the present invention, and FIG. 2 is a perspective view showing an ultrasonic imaging device according to an embodiment of the present invention. As shown in FIG. 1, the ultrasonic imaging device 1 uses ultrasonic waves to non-destructively measure the inside of a test specimen in water W as an ultrasonic transmission medium, displays an exploration image of the test specimen, and determines whether or not there are internal defects.

[0013] The ultrasonic imaging device 1 is disposed in a water tank 10, and is configured to include a sample stage 20 on which a wafer 2 (test object) is placed, a first ultrasonic probe 40 provided above the wafer 2, and a second ultrasonic probe 50 provided below the wafer 2. The first ultrasonic probe 40 and the second ultrasonic probe 50 are disposed at positions facing each other in the vertical direction (Z direction). The wafer 2 is, for example, a circular thin plate that is used as a material for semiconductor integrated circuits.

[0014] The first ultrasonic probe 40 is an irradiation probe that irradiates ultrasonic waves toward the wafer 2. The second ultrasonic probe 50 is a receiving probe that receives ultrasonic waves that have passed through the wafer 2. Note that, contrary to this embodiment, the second ultrasonic probe 50 may be an irradiation probe and the first ultrasonic probe 40 may be a receiving probe.

[0015] The sample stage 20 is held by a sample stage holder 30 and arranged horizontally in the water tank 10. The water in the water tank 10 is not limited to pure water, but may be tap water, and is not particularly limited. The shape of the water tank 10 is not limited to a rectangular box as in this embodiment, but may be, for example, a cylindrical shape with a bottom. The configuration and function of the sample stage 20 will be described in detail later.

[0016] The first ultrasonic probe 40 and the second ultrasonic probe 50 are arranged above and below each other with the wafer 2, which is the test subject, sandwiched between them, and are configured to be movable by an X-axis scanning unit 61, a Y-axis scanning unit 62 (see Figure 2) and a Z-axis scanning unit 63, which are connected to a driving device (not shown).

[0017] As shown in FIG. 2, the X-axis scanning unit 61 is provided above the water tank 10, and moves both the first ultrasonic probe 40 and the second ultrasonic probe 50 in the X-axis direction (left and right direction).

[0018] The Y-axis scanning units 62 are provided as a pair on both sides in the X-axis direction outside the water tank 10, and operate both the first ultrasonic probe 40 and the second ultrasonic probe 50 in the Y-axis direction (front-back direction).

[0019] The Z-axis scanning unit 63 is attached to the X-axis scanning unit 61 via a slider 65, and moves the first ultrasonic probe 40 in the Z-axis direction (up and down direction). The first ultrasonic probe 40 is attached to the Z-axis scanning unit 63 via a probe holder 64.

[0020] 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). The second ultrasonic probe 50 is located at the tip of the arm 66 at a position facing the first ultrasonic probe 40. The second ultrasonic probe 50 is not movable 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 may be movable in the Z-axis direction (up and down direction) together with the first ultrasonic probe 40.

[0021] The wafer 2 is held on a sample stage 20 and placed in water W stored in a water tank 10. The first ultrasonic probe 40 is placed above the wafer 2 in the Z-axis direction, and the second ultrasonic probe 50 is placed below the wafer 2 in the Z-axis direction.

[0022] The sample stage 20 on 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 legs 22. A space is formed between the sample stage holder 30 and the bottom surface of the water tank 10 for the second ultrasonic probe 50 to move in the X-axis and Y-axis directions. Note that, although the example in which the legs 22 are provided at the four corners of the sample stage holder 30 has been described, the present embodiment is not limited to this embodiment as long as the sample stage holder 30 can be fixed to the water tank 10.

[0023] 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 pressing member is removed from the sample stage holder in Fig. 3, and Fig. 5 is an enlarged view of the receiving member in Fig. 4. Note that all of Figs. 3 to 5 show 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 having a circular opening 21 formed therein. The thickness of the sample stage 20 is set to a thickness that ensures the rigidity required for stable support of the wafer 2 when placed thereon, for example, about 2 to 10 mm. The material of the sample stage 20 is preferably a strong member such as aluminum or stainless steel. By using such a material, it is possible to reduce the influence of vibrations caused when the first ultrasonic probe 40 and the second ultrasonic probe 50 (probes) move in the water W. The shape of the sample stage 20 is not limited to a rectangular shape, and may be, for example, an elliptical shape.

[0024] The sample stage 20 is provided with a receiving member 71 for holding the wafer 2 in the opening 21. The sample stage 20 is also provided with a pressing member 72 for pressing the wafer 2 on the edge of the upper surface side of the opening 21. The edge of the wafer 2 is sandwiched between the receiving member 71 and the pressing member 72, thereby holding the wafer 2 in the opening 21. Three pairs of receiving members 71 and pressing members 72 (hereinafter collectively referred to as gripping members) are disposed on the edge of the opening 21 so as to stably hold the wafer 2. Note that while at least three gripping members are required to stably hold the wafer 2, the number may be two or less or four or more depending on the size of the wafer 2.

[0025] The pressing member 72 is formed long and thin along the edge of the opening 21, and is disposed at a position facing the receiving member 71 in the up-down direction. The pressing member 72 is fixed to the edge of the opening 21 of the sample stage 20 with screws. In this embodiment, the pressing member 72 is fixed at both ends in the longitudinal direction.

[0026] The sample stage holding part 30 holds the sample stage 20, and is configured to include a sample stage lower presser 31 that presses the lower side of the sample stage 20, and a sample stage upper presser 32 that presses the upper side of the sample stage 20. In this way, the sample stage holding part 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 stage lower presser 31 has a lower presser part 31a arranged along both edges of the sample stage 20 in the X-axis direction, and a connecting part 31b that connects one end (rear end) of the lower presser part 31a in the Y-axis direction. The sample stage upper presser 32 is provided along both edges of the sample stage 20 in the X-axis direction, and is provided overlapping the lower presser part 31a. In addition, the sample stage upper presser 32 is fixed to the lower presser part 31a by a screw. Further, a positioning member 33 is provided on the upper surface of the joint portion 31b of the sample stage holding portion 30, with which the rear end of the sample stage 20 comes into contact to determine the insertion position of the sample stage 20.

[0027] 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. The receiving member 71 is formed in a trapezoid shape, and a contact portion 71a that contacts the outer periphery of the wafer 2 is formed at the tip of the inner diameter side. The receiving member 71 is also formed with a support portion 71b that protrudes radially inward from the lower end of the contact portion 71a and supports the wafer 2. The support portion 71b is flange-shaped and contacts the lower surface of the edge of the wafer 2 to support it. By providing three receiving members 71 in this way, 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.

[0028] Fig. 6 is a perspective view showing a state in which the sample stage is held by the sample stage holder 30. Note that Fig. 6 illustrates a state in which one side in the X-axis direction of the sample stage holder 30 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 portions 20a, 20a held by the sample stage holding portion 30 are formed on both ends in the Y-axis direction.

[0029] The sample stage upper presser 32 is cut out in a concave shape except for both ends in the Y-axis direction, and presser parts 32a are formed at both ends in the Y-axis direction so as to overlap the held parts 20a. A notch 32b is formed on the inside of the presser part 32a to guide the held part 20a of the sample stage 20 so that the held part 20a can slide. That is, the held part 20a is inserted from the front side in the Y-axis direction and is inserted to a predetermined position of the sample stage holding part 30 while sliding. Note that in this embodiment, only one side in the X-axis direction is illustrated and described, but the other side is configured in the same way.

[0030] FIG. 7 is a top view showing a state in which the sample stage on which the wafer is 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 a result, a gap S (air bubble discharge portion) for removing air bubbles is formed between the (edge) of the opening 21 formed in the sample stage 20 and the outer periphery of the wafer 2. The gap S is an arc-shaped hole formed penetrating the opening 21 in the axial direction (perpendicular to the paper surface). Note that the holes penetrating in the vertical direction (Z-axis direction) are blocked at the positions where the receiving member 71 and the pressing member 72 are provided. That is, the opening 21 has the gap S at the outer periphery of the wafer 2 except for the position where the gripping member is disposed by gripping the wafer 2. The larger the gap S, the easier it is to remove air bubbles, but the gripping member needs to be configured to be larger in order to hold the wafer 2.

[0031] Furthermore, the wafer 2 is positioned within the opening 21 by abutting against the abutment portion 71a (see FIG. 5) of the receiving member 71, and a gap S can be reliably secured between the opening 21 and the wafer 2. The size of the gap S (the radial distance between the edge of the opening 21 and the outer periphery of the wafer 2) is appropriately set according to the purpose, etc., within a range that does not impair the effect.

[0032] In addition, the wafer 2 is held down by the holding member 72 so that the wafer 2 does not fall out of the opening 21. The holding member 72 has a long and narrow plate shape extending in the circumferential direction, and a curved portion 72a is formed on the radially inner side so as to have a shape that follows the curvature of the outer periphery of the wafer 2. This makes it possible to reduce the area where the wafer 2 and the holding member 72 overlap in the Z-axis direction (perpendicular to the paper surface), and to expand the inspection range of the wafer 2.

[0033] The material of the receiving member 71 and the pressing member 72 is not particularly limited as long as it does not damage the wafer 2, and examples of such materials include resin materials such as polyethylene and acrylic. Although not shown, by making the screw holes for fixing the pressing member 72 with screws long holes in the direction of the wafer 2 (test object), the pressing member 72 can move within the range of the long holes, which makes it easier to install the wafer 2.

[0034] Furthermore, the pressing portion 32a of the sample stage upper pressing portion 32 is provided with a leaf spring 80 for holding the sample stage 20. The held portion 20a (see FIG. 6) of the sample stage 20 is inserted into the position of the pressing portion 32a, whereby the held portion 20a is held by the leaf spring 80. This allows the sample stage 20 to be stably held on the sample stage holding portion 30. Note that, in the present embodiment, the leaf springs 80 are provided at the four corners of the sample stage 20, but as long as the sample stage 20 can be held, the leaf springs 80 may be provided at two locations on the front side or two locations on the back side, and the number and positions of the leaf springs 80 are not limited.

[0035] FIG. 8 is a top view showing a state in which the sample stage holding the wafer is in the process of being attached to the sample stage holder. As shown in FIG. 8, after the wafer 2 is held on the sample stage 20, the sample stage 20 is horizontally arranged on the front side of the sample stage holding part 30 in the Y-axis direction, and the rear held part 20a is inserted from the front side of the sample stage holding part 30 and slid toward the rear side in the Y-axis direction. As a result, the held part 20a is inserted between the lower pressing part 31a and the front side pressing part 32a while being guided toward the rear side in the Y-axis direction. Then, after the held part 20a passes the pressing part 32a, the rear side held part 20a reaches between the lower pressing part 31a and the pressing part 32a on the rear side in the Y-axis direction, and the front side held part 20a in the Y-axis direction reaches the pressing part 32a on the front side. By sliding the sample stage 20 further toward the rear from this state and pushing it in, all the held parts 20a at the four corners are inserted between the lower pressing part 31a and the pressing part 32a, and the held parts 20a are held by the leaf springs 80, respectively.

[0036] Next, the procedure from placing the wafer 2 on the sample stage 20 to placing the sample stage 20 on the sample stage holder 30 will be described. First, the wafer 2 is placed on 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 peripheral surface of the wafer 2 abuts against the abutting portion 71a, so that the wafer 2 is positioned in the opening 21 with a gap S formed between the outer periphery of the wafer 2 and the opening 21 (see FIGS. 5 and 7). Then, the pressing member 72 is disposed on the edge of the opening 21 so as to overlap the edge of the wafer 2, and the pressing member 72 is fixed to the sample stage 20 by a screw. In this manner, the wafer 2 is fixed to the sample stage 20 by the gripping members (the receiving member 71 and the pressing member 72).

[0037] Then, the sample stage 20 on which the wafer 2 is fixed is immersed in the water W in the water tank 10, and the sample stage 20 is tilted or the like to remove any air bubbles trapped under the bottom surface of the wafer 2. If any air bubbles remain that cannot be removed by the above procedure, they are removed by blowing a stream of water into the area where the air bubbles were found. In particular, fine air bubbles trapped between the wafer 2 and the opening 21 are removed by the water stream through the gap S (air bubble exhaust section). 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.

[0038] Then, with the sample stage 20 holding the wafer 2 held horizontally at the front side of the sample stage holding part 30, the sample stage 20 is slid from the front side of the sample stage holding part 30 and fitted into the sample stage 20, thereby fixing the sample stage 20 to the sample stage holding part 30. The sample stage holding part 30 is fixed inside the water tank 10 (see FIG. 2).

[0039] In this way, the wafer 2 is fixed to the sample stage 20 outside the water tank 10, and then the sample stage 20 is placed in the water W and slid into the sample stage holding portion 30 to be fixed, thereby improving the workability when fixing the wafer 2.

[0040] Next, the operation and function of the ultrasonic imaging device 1 will be described. When a wafer 2 (specimen) to be inspected is placed in the water W, the first ultrasonic probe 40 and the second ultrasonic probe 50 move horizontally relative to the sample stage 20 to scan the wafer 2 in order to inspect the inside of the wafer 2. Before the inspection, the first ultrasonic probe 40 is retracted above and away from the second ultrasonic probe 50, and when the wafer 2 is placed in a predetermined position, the first ultrasonic probe 40 is lowered from the origin position to the focal position.

[0041] The ultrasonic imaging device 1 utilizes the property that the strength of ultrasonic waves after passing through the wafer 2 (test object) varies depending on the acoustic impedance of each part of the wafer 2, and images the strength of the received ultrasonic waves. This makes it possible to non-destructively inspect the state inside the wafer 2.

[0042] Next, a method of operating the ultrasonic imaging device 1 will be described. In order to obtain the desired effects in the ultrasonic imaging device 1 having the air bubble discharge mechanism of this embodiment, a test operation is carried out prior to actual operation of the ultrasonic imaging device 1. 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 specimen (wafer 2) to be inspected. In other words, the area and shape of the opening 21 are set so that when the specimen (wafer 2) is gripped by the gripping members (receiving member 71 and pressing member 72), a gap S (air bubble exhaust portion) large enough to exhaust air bubbles is formed between the specimen (wafer 2) and the opening 21. Through this test operation, it becomes possible to prevent air bubbles from remaining around the specimen (wafer 2) in the actual operation as well, and the operational efficiency can be improved.

[0043] As described above, the ultrasonic imaging device 1 of this embodiment is an ultrasonic imaging device 1 that irradiates ultrasonic waves onto the wafer 2 and acquires and images the transmitted waves, and includes a sample stage 20 that fixes the wafer 2 in water W. The sample stage 20 has an opening 21, and the edge of the opening 21 is provided with gripping members (receiving member 71 and pressing member 72) that grip the wafer 2. The opening 21 is configured to be larger than the wafer 2, and by gripping the wafer 2 with the gripping members, a gap S (air bubble discharge portion) is formed between the outer periphery of the wafer 2 and the edge of the opening 21. This allows fine air bubbles adhering to the periphery of the wafer 2 mounted on the sample stage 20 to be easily discharged from the gap S.

[0044] In this embodiment, the gap S (air bubble discharge portion) is formed at a position other than the position where the gripping member is disposed. This allows the gripping member to be configured so as to stably grip the wafer 2.

[0045] Moreover, in this embodiment, three or more gripping members (receiving members 71 and pressing members 72) are provided, and the gripping members are disposed at equal intervals on the edge of the opening 21. This allows the wafer 2 to be stably held on the sample stage 20.

[0046] In this embodiment, the gripping member is composed of a receiving member 71 arranged below the wafer 2 for placing the wafer 2 thereon, and a pressing member 72 arranged above the wafer 2 for pressing the wafer 2. With this, the wafer 2 can be stably held on the sample stage 20 by pressing the wafer 2 from above and below with the edges thereof.

[0047] In this embodiment, the sample stage 20 is held by the sample stage holder 30, and the sample stage holder 30 is fixed to the water tank 10 in which the sample stage 20 is immersed. Since the wafer 2 is fixed to the sample stage 20 outside the water tank 10, workability is improved compared to when the wafer 2 is fixed inside the water tank 10.

[0048] The present invention is not limited to the above-described embodiment. For example, in the present embodiment, a circular opening 21 has been described as an example, but the opening is not limited to a circular shape. The shape of the opening excluding the gripping member may be a shape that bulges outward, and the gap between the opening and the outer periphery of the wafer 2 may be larger than in the present embodiment. [Explanation of symbols]

[0049] 1. Ultrasound imaging device 2 Wafer (subject) 10. Aquarium 20 Sample stage 21 Opening 30 Sample holder 40 First ultrasound probe 50 Second ultrasound probe 71 Supporting member 72 Holding member S Gap (air bubble exhaust area) W water

Claims

1. An ultrasound imaging device that irradiates an object with ultrasound and acquires and visualizes the transmitted waves, a sample stage for fixing the specimen 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 object, and a bubble discharge portion is formed between an outer periphery of the object and an edge of the opening by gripping the object with the gripping member.

2. 2. The ultrasonic imaging device according to claim 1, The ultrasonic imaging device according to claim 1, wherein the bubble discharge portion is formed at a position other than a position where the gripping member is disposed.

3. 2. The ultrasonic imaging device according to claim 1, 2. An ultrasonic imaging device comprising: three or more gripping members, the gripping members being disposed at equal intervals on the edge of the opening.

4. 2. The ultrasonic imaging device according to claim 1, 4. An ultrasonic imaging apparatus according to claim 1, wherein the holding member is composed of a receiving member arranged below the subject and on which the subject is placed, and a pressing member arranged above the subject and which presses the subject.

5. 2. The ultrasonic imaging device according to claim 1, The sample stage is held by a sample stage holder, 2. The ultrasonic imaging apparatus according to claim 1, wherein the sample stage holder is fixed to a water tank in which the sample stage is immersed.

6. In a preliminary stage before the actual operation of the ultrasonic imaging device according to any one of claims 1 to 5, 11. A method for operating an ultrasonic imaging apparatus, comprising: setting an area and a shape of the opening in accordance with an area and a shape of the object so as to prevent air bubbles from remaining around the object.

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