Method for controlling probe unit of ultrasonic inspection apparatus, probe unit of ultrasonic inspection apparatus, and ultrasonic inspection apparatus

Abstract

A method for controlling a probe unit (2) of an ultrasonic inspection apparatus, comprising: a step (S1) for moving the probe unit (2) below a subject (E) such that a distance between a lower surface of the subject (E) and an upper surface of the probe unit (2) becomes a predetermined distance; a step (S2) for starting supply of water to a space (10) formed between the lower surface of the subject (E) and an upper surface of a probe nozzle; and a step (S3) for forming a water layer (W1) in the space (10) by temporarily changing at least one of a height of the probe unit (2) with respect to the subject (E) and an amount of water supplied to the space (10) from the height of the probe unit and the amount of water used when matching a focal point (P) of a probe (21) with an inspection target part (E1) of the subject (E) in a state in which the water layer (W1) is formed in the space (10).

Description

Control Method for Probe Unit of Ultrasonic Inspection Device, Probe Unit of Ultrasonic Inspection Device, and Ultrasonic Inspection Device

[0001] The present disclosure relates to a control method for a probe unit of an ultrasonic inspection device, a probe unit of an ultrasonic inspection device, and an ultrasonic inspection device.

[0002] Patent Document 1 describes that "an ultrasonic imaging device 100 is a device that irradiates ultrasonic waves onto a bonded wafer 109 in which two or more wafers 191 are bonded to generate an image of the bonding surface 193 between the wafers. Below the bonded wafer 109, an ultrasonic probe 110 that irradiates ultrasonic waves onto the bonded wafer, and between the bottom surface 109a of the bonded wafer 109, a liquid discharge unit 111 that continuously discharges liquid toward the bottom surface 109a so that a liquid film 106 that contacts the bottom surface 109a is formed, and moves together with the ultrasonic probe 110, and a gas discharge device 102 that discharges gas. The gas discharge device 102 discharges gas for pushing down the liquid toward the outer peripheral end 199 of the bonded wafer 109 so that the liquid discharged from the liquid discharge unit 111 does not enter the bonding surface 193 from the outer peripheral end 199 of the bonded wafer 109."

[0003] Japanese Patent Application Laid-Open No. 2023 - 170546

[0004] In Patent Document 1, ultrasonic inspection of the specimen (bonded wafer) is performed in a state where a water layer is formed in the space between the lower surface of the specimen and the upper surface of the probe unit. That is, ultrasonic waves propagate through the water layer blown out from below. However, the method of forming the water layer in the space is not described, and it is desired to easily form a water layer suitable for ultrasonic inspection. The problem to be solved by the present disclosure is to provide a control method for a probe unit of an ultrasonic inspection device, a probe unit of an ultrasonic inspection device, and an ultrasonic inspection device that can easily form a water layer suitable for ultrasonic inspection.

[0005] The method for controlling a probe unit of an ultrasound inspection apparatus according to the present disclosure is a method for controlling a probe unit of an ultrasound inspection apparatus that performs ultrasound inspection by forming a layer of water in the space between the tip of an ultrasound probe and a subject, and includes: a movement step of moving the probe unit, which comprises a probe, a probe nozzle covering the probe, and an inlet for supplying water to the probe nozzle, downward of the subject so that the distance between the lower surface of the subject and the upper surface of the probe unit is a predetermined distance; a supply start step of starting to supply water to the space formed between the lower surface of the subject and the upper surface of the probe nozzle through the inlet and a water supply port for supplying water from the probe nozzle to the subject; and a formation step of temporarily changing at least one of the height of the probe unit relative to the subject or the amount of water supplied to the space from the height and amount of water supplied when the probe is focused on the part of the subject to be inspected while a layer of water is formed in the space, thereby forming a layer of water in the space. Other solutions will be described later in the embodiments for carrying out the invention.

[0006] According to this disclosure, a control method for a probe unit of an ultrasound inspection apparatus that can easily form a water layer suitable for ultrasound inspection, a probe unit of an ultrasound inspection apparatus, and an ultrasound inspection apparatus can be provided.

[0007] This is a flowchart illustrating the control method for the probe unit of the ultrasound examination apparatus of this disclosure. This is a block diagram of the ultrasound examination apparatus of this disclosure. This is a block diagram showing the specific hardware configuration of the control device. This is a diagram illustrating the movement step, showing the probe unit positioned below the subject. This is a diagram illustrating the formation step, showing the formation of a water layer in the space between the upper and lower surfaces. This is a diagram illustrating the relationship between the hydrophilicity of the upper surface and the height of the water layer, showing the water layer formation state when the hydrophilicity is low. This is a diagram illustrating the relationship between the hydrophilicity of the upper surface and the height of the water layer, showing the water layer formation state when the hydrophilicity is high. This is a diagram showing the water layer formation state when the hydrophilicity of the upper surface is high and the focal length is long. This is a diagram illustrating the water layer formation state when the hydrophilicity of the upper surface is high and the focal length is short. This is a diagram illustrating the first step, showing the probe's focus set to a position further from the probe than the area to be examined. This is a diagram illustrating the second step, showing the probe's focus aligned with the area to be examined. This is a diagram showing the state when the probe unit reaches the edge of the subject during ultrasound examination. This is a diagram illustrating the case where the amount of water formed in the space between the upper and lower surfaces is excessive. This is a cross-sectional view of a hydrophilic membrane.

[0008] The following describes embodiments for implementing this disclosure, with reference to the drawings. The following is merely an example of how to implement the invention related to this disclosure, and this disclosure is not limited to the following example. Within the description of one embodiment below, other embodiments applicable to that embodiment will also be described as appropriate. This disclosure is not limited to the following embodiment, and different embodiments can be combined or modified as appropriate without significantly impairing the effects of this disclosure. In addition, the same reference numerals will be used for the same components, and redundant explanations will be omitted. Furthermore, components having the same function will be given the same name. The illustrations are schematic, and for illustrative purposes, the actual configuration may be changed or some components may be omitted or modified between drawings without significantly impairing the effects of this disclosure. Also, the same embodiment does not necessarily need to have all the components.

[0009] Figure 1 is a flowchart showing a control method for the probe unit 2 of the ultrasound examination apparatus 1 (Figure 2) of the present disclosure (hereinafter simply referred to as "the control method of the present disclosure," etc.). The control method of the present disclosure includes steps S1 to S4. The control method of the present disclosure is, for example, a method for controlling the driving of the probe unit 2 to form a layer of water (water layer W1) in the space 10 between the subject E and the probe unit 2 before ultrasound examination in the ultrasound examination apparatus 1. As will be described in detail later, the control method of the present disclosure is also a method for aligning the probe unit 2 in the height direction.

[0010] As will be described in detail later, the formation of the aqueous layer W1 is achieved by adjusting the hydrophilicity (or hydrophobicity) of the upper surface 20 of the probe nozzle 22, thereby forming an appropriate aqueous layer W1 (which is also a film of water W) in the space 10 between the probe nozzle 22 and the subject E. An appropriate aqueous layer W1 is an aqueous layer that is in contact with both the upper surface 20 of the probe nozzle 22 and the lower surface E2 of the subject E. After the formation of the aqueous layer W1, the probe unit 2 is moved away from the subject E so that the focal point P aligns with the area to be examined E1. When it is moved away, that is, when the probe unit 2 is lowered, the aqueous layer W1 is maintained in an appropriately formed state by the surface tension of the water W. Note that the control method of this disclosure is usually performed only once, for example, at an arbitrary position below the subject E, before the ultrasound examination.

[0011] The ultrasound examination apparatus 1 of this disclosure is an apparatus that performs ultrasound examination by forming a water layer W1, which is a layer of water W, in the space 10 between the tip of an ultrasound probe 21 and a subject E. In this example of the disclosure, the ultrasound examination apparatus 1 discharges water W from below upward and performs ultrasound examination of the subject E through the formed water layer W1. The ultrasound examination is performed by propagating ultrasound U through the water layer W1.

[0012] Figure 2 is a block diagram of the ultrasound inspection apparatus 1 of the present disclosure. The ultrasound inspection apparatus 1 comprises a probe unit 2, a scanning measurement device 3, and a control device 4. In the example of the present disclosure, the scanning measurement device 3 comprises the probe unit 2.

[0013] The probe unit 2 is a structure that transmits ultrasonic waves U toward the subject E and receives the ultrasonic waves U reflected by the part E1 of the subject E that is to be examined. The specific configuration of the probe unit 2 will be described later. The scanning measurement device 3 is a device that drives the probe unit 2 in a predetermined direction. The predetermined direction includes, for example, the xy direction (not shown) and the z direction (not shown). Drive control in the xy direction is mainly performed during ultrasonic examinations while transmitting and receiving ultrasonic waves U. Drive control in the z direction is performed before the ultrasonic examination when a suitable water layer W1 is formed in the space 10. The scanning measurement device 3 includes, for example, an actuator (not shown).

[0014] The control device 4 is a device that controls the operation of the ultrasonic inspection apparatus 1, which includes the scanning measuring device 3. Specifically, the control device 4 controls the operation of the probe unit 2 and the scanning measuring device 3. More precisely, the control device 4 is a device that, for example, controls the transmission and reception of ultrasonic waves U in the probe unit 2, and controls the drive of the probe unit 2 in the x and y directions using the scanning measuring device 3.

[0015] Figure 3 is a block diagram showing the specific hardware configuration of the control device 4. The control device 4 is configured to include, for example, a CPU (Central Processing Unit) 1001, a RAM (Random Access Memory) 1002, a ROM (Read Only Memory) 1003, an I / F (Interface) 1004, a bus 1005, etc. The CPU 1001, RAM 1002, ROM 1003, and I / F 1004 are connected, for example, via the bus 1005. The control device 4 is realized when a predetermined control program (for example, a control method or ultrasonic inspection method of this disclosure) stored in the ROM 1003 is loaded into the RAM 1002 and executed by the CPU 1001. Signals and information are exchanged between the control device 4 and various devices (scanning and measuring device 3, server, etc.) and external networks, etc., via the I / F 1004 in hardware terms.

[0016] Figure 4 is a diagram illustrating step S1 shown in Figure 1, and shows the probe unit 2 positioned below the object to be inspected E. Step S1 is a moving step in which the probe unit 2 is moved downwards from the object to be inspected E so that the distance between the lower surface E2 of the object to be inspected E and the upper surface 20 of the probe unit 2 is a predetermined distance. The upper surface 20 of the probe unit 2 is also the upper surface 20 of the probe nozzle 22. The object to be inspected E is, for example, a wafer which is a laminate consisting of multiple layers, but it may also be a single-layer object consisting of only one layer. In the example of this disclosure, the bonding interface between each layer is the inspection target part E1. Bubbles, defects, etc. that may be present in the inspection target part E1 can be detected by ultrasonic inspection.

[0017] The probe unit 2 is used in the control method of the present disclosure. The probe unit 2 comprises an ultrasound probe 21, a probe nozzle 22 covering the probe 21, and a water inlet 23 for supplying water to the probe nozzle 22. The probe 21 is a structure that transmits ultrasound U to the subject E and receives ultrasound U reflected from the part to be examined E1 and the lower surface E2. The probe 21 includes, for example, a piezoelectric element (not shown).

[0018] A probe nozzle 22 is positioned around the probe 21. The probe nozzle 22 is hollow and has a water passage 24 inside. The water passage 24 is formed to surround the probe 21. The water passage 24 is connected to an inlet 23, such as an opening, and a water supply port 25 that discharges water W into the space 10. The water supply port 25 is an opening, such as a probe nozzle 22, that supplies water W to the subject E. For example, water W is introduced into the water passage 24 through the inlet 23 using a pump (not shown). The water W that has flowed through the water passage 24 is discharged into the space 10 from the water supply port 25, thereby forming a water layer W1 (water film), which is a layer (film) of water W, in the space 10 formed between the lower surface E2 and the upper surface 20.

[0019] The probe nozzle 22 is fixed to the probe 21, for example, so as to cover the tip surface (upper end surface) of the probe 21. Fixing is done, for example, by a screw or other fastener. The screw is made of, for example, resin. The probe nozzle 22 is also made of, for example, resin.

[0020] On the probe unit 2, irregularities 201 are formed on at least a portion of the upper surface 20, which is the surface facing the subject E. As described above, the upper surface 20 is the upper surface of the probe unit 2 and also the upper surface of the probe nozzle 22. In this way, the surface properties of the upper surface 20 can be changed from a state where no irregularities 201 are intentionally formed (for example, a smooth surface).

[0021] Specifically, for example, by forming the irregularities 201, the surface area of ​​the upper surface 20 increases compared to, for example, a flat surface, thus improving hydrophilicity and hydrophobicity. For example, if the upper surface 20 is hydrophilic, the hydrophilicity can be increased by forming the irregularities 201. On the other hand, if the upper surface 20 is hydrophobic, the hydrophobicity can be increased by forming the irregularities 201. Furthermore, the higher the hydrophilicity (lower the hydrophobicity), the more the water W spreads, and the lower the height (thickness) of the water layer W1. Conversely, the lower the hydrophilicity (higher the hydrophobicity), the less the water W spreads, and the higher the height (thickness) of the water layer W1. Therefore, the height of the water layer W1 formed on the upper surface 20 can be adjusted by selecting the material of the probe nozzle 22.

[0022] In the example of this disclosure, the irregularities 201 are formed on the entire upper surface 20. However, the irregularities 201 may be formed in an annular or band shape, for example, to surround the water inlet 25. The method for forming the irregularities 201 will vary depending on the material of the probe nozzle 22, but can be carried out by any method, such as blasting or filing.

[0023] Of the probe unit 2, at least the component forming the upper surface 20, which faces the subject E, is made of resin. This suppresses metal contamination that would occur if metal were used. Note that "made of resin" here does not necessarily mean "made only of resin" (containing no other materials), but rather that the main component (the most abundant material component) is resin. In particular, when the irregularities 201 are formed, fine powder of the constituent material of the probe nozzle 22 may be generated, but if the probe nozzle 22 is made of resin, for example, the generated fine powder will also be made of resin. Therefore, even if the generated fine powder cannot be completely removed, metal contamination can be suppressed. For this reason, it is preferable that the probe unit 2 does not contain metal.

[0024] In particular, it is preferable that the main component of the member forming the upper surface 20, which is the surface facing the subject E, is polyethylene. Here, "main component" refers to the material component that is most abundant among the constituent materials. Polyethylene has excellent flexibility, making it easy to handle, and it is stable in the environment during ultrasound examination. Therefore, even if the member containing polyethylene as the main component is deformed (strained, etc.) due to the formation of the film 202 described later, the deformation can be resolved and it can be returned to the desired shape. When the main component of the member forming the upper surface 20, which is the surface facing the subject E, is polyethylene, it is preferable that it further contains a conductive filler. This makes it possible to impart conductivity to polyethylene, which does not have conductivity, by means of a conductive filler. The content of the conductive filler is not particularly limited, but it should be sufficient to impart conductivity to at least the upper surface 20. The conductive filler is, for example, a conductive carbon material (e.g., carbon fiber).

[0025] In the example of this disclosure, the entire probe nozzle 22, including the upper surface 20, is made of resin (preferably polyethylene). This suppresses the leaching of metals into the water W due to corrosion of metals, etc., and reduces the risk of metal-derived contamination. Furthermore, it is preferable that the entire probe nozzle 22 is made of resin containing a conductive filler (for example, a conductive carbon material).

[0026] The resin forming at least the upper surface 20 may be hydrophilic or hydrophobic. For example, using a hydrophilic resin allows the water layer W1 to be made thinner, reducing the attenuation of ultrasonic waves U in the water layer W1. On the other hand, using a hydrophobic resin (e.g., a thermoplastic resin) allows the use of a general-purpose resin that is easy to mold. Furthermore, the resin may be conductive or non-conductive. As mentioned above, the resin may be a non-conductive resin (e.g., polyethylene) containing a conductive material (e.g., a conductive filler, a conductive carbon material, etc.).

[0027] The degree of the irregularities 201 is not particularly limited. For example, the portion of the upper surface 20 on which the irregularities 201 are formed has a roughness such that individual irregularities 201 cannot be seen by a person with the naked eye, i.e., without using a microscope, magnifying lens, etc. Therefore, when a person quickly looks at the upper surface 20 (the portion on which the irregularities 201 are formed) with the naked eye, the irregularities 201 do not appear to exist at first glance, and the upper surface 20 appears to be a flat surface (smooth surface). In this way, the hydrophilicity and hydrophobicity can be improved when water W comes into contact with the upper surface 20, and the height of the water layer W1 can be easily controlled. Furthermore, the degree to which the hydrophilicity and hydrophobicity are improved can be controlled by changing the degree of the irregularities 201 (for example, the value of the arithmetic mean roughness Ra described later).

[0028] The roughness to which individual irregularities 201 cannot be seen with the naked eye can also be defined as, for example, the roughness to which the reflection of natural light on the top surface 20 cannot be seen with the naked eye when the top surface 20 is viewed by a person. Specifically, the roughness to which individual irregularities 201 cannot be seen with the naked eye when the top surface 20 is viewed by a person can be defined as, for example, an arithmetic mean roughness Ra of 0.5 μm or more and 10 μm or less, preferably 0.75 μm or more and 7.5 μm or less, more preferably 1 μm or more and 5 μm or less, even more preferably 1.5 μm or more and 4 μm or less, and particularly preferably 1.75 μm or more and 3 μm or less. The arithmetic mean roughness Ra can be measured, for example, based on JIS B 0601-2001.

[0029] A hydrophilic or hydrophobic film is formed on at least a portion of the upper surface 20, which is the surface facing the subject E. In this way, the properties of the upper surface 20 can be made either hydrophilic or hydrophobic. In the example of this disclosure, a hydrophilic (or hydrophobic as described above) film 202 is formed on at least the portion of the upper surface 20 in which the irregularities 201 are formed. By providing the film 202, the surface properties of the upper surface 20 can be made hydrophilic. In particular, since the film 202 is formed on the portion in which the irregularities 201 are formed, hydrophilicity can be improved compared to the case in which the irregularities 201 are formed on a smooth surface. The composition, internal structure, etc. of the film 202 will be described in detail later with reference to Figure 14.

[0030] In the example of this disclosure, the film 202 is made of an inorganic material, while the upper surface 20, which includes the irregularities 201, is made of an organic material, such as a resin. Since the film 202 is joined to the probe nozzle 22 at the portion of the irregularities 201 where the surface area is larger, the joining area is larger compared to joining on a smooth surface. This allows for a physical anchoring effect and improves the joining strength.

[0031] Therefore, the portion where the irregularities 201 are formed is composed of either an organic or inorganic material, and the hydrophilic (or hydrophobic) film 202 is composed of the other organic or inorganic material. In this way, a physical anchoring effect can be achieved as described above, and the bonding strength between the organic and inorganic materials can be improved.

[0032] Depending on the type of resin, resins commonly used in ultrasonic inspection devices 1, such as polyethylene (PE), polypropylene (PP), polyetheretherketone (PEEK), and acrylonitrile-butadiene-styrene resin (ABS resin), are often hydrophobic. Therefore, water W is easily repelled as droplets on the upper surface 20, making it difficult to form the desired water layer W1. However, by providing a hydrophilic film 202 on the surface of the unevenness 102 (on top of the unevenness 102), the desired water layer W1 capable of transmitting ultrasonic waves U can be formed.

[0033] As explained with reference to Figure 1 above, after the probe unit 2 moves in step S1, the distance L between the lower surface E2 and the upper surface 20 is a predetermined distance. This predetermined distance is, for example, a distance unique to each probe 21, and is different for each focal length of the probe 21. When the distance L between the lower surface E2 and the upper surface 20 is set to the predetermined distance, the focal point P of the probe 21 may or may not be aligned with the part to be inspected E1. Furthermore, distance L is the distance between the outer surface of the membrane 202 and the lower surface E2, and refers to the distance of the longest part between them.

[0034] Figure 5 illustrates steps S2 and S3 shown in Figure 1, and shows the formation of a layer of water W (water layer W1) in the space 10 between the upper surface 20 and the lower surface E2. After the supply of water W is started in step S2, the supply of water W to the space 10 continues at least until the control method of this disclosure is completed. Therefore, in Figure 5 as well, water W continues to be supplied, and there is water W that has overflowed (spilled) from the upper surface 20, but the illustration of the overflowed water W is omitted in Figure 5. This point is also the same in subsequent figures unless otherwise specified.

[0035] Step S2 shown in Figure 1 above is a supply initiation step in which water is supplied to the space 10 formed between the lower surface E2 of the subject E and the upper surface 20 of the probe nozzle 22 through the inlet 23 and the water supply port 25. The water supply port 25 is an opening that supplies water W from the probe nozzle 22 to the subject E. The water supply port 25 is formed on the upper surface 20, which is the tip of the probe nozzle 22 (probe unit 2). The water supply port 25 is, for example, a circular opening, and ultrasonic waves U are transmitted and received at the center of the water supply port 15. The supply of water W to the space 10 initiates the formation of the water layer W1.

[0036] When water W is supplied to the top surface 20 without overflowing (spilling), the height of the water layer W1 increases. As described above, when the hydrophilicity of the top surface 20 is high (i.e., when the hydrophobicity is low), the supplied water W spreads easily. For this reason, the height of the water layer W1 is low. Also, even with the same hydrophilicity, if it is relatively high, it spreads relatively easily, and the height of the water layer W1 is relatively low. On the other hand, when the hydrophilicity of the top surface 20 is low (i.e., when the hydrophobicity is high), the supplied water W does not spread easily. For this reason, the height of the water layer W1 is high. Also, even with the same hydrophobicity, if it is relatively high, it spreads relatively difficult, and the height of the water layer W1 is relatively high. Therefore, the height of the water layer W1 can be adjusted by adjusting the wettability (degree of hydrophilicity or hydrophobicity) of the top surface 20.

[0037] Furthermore, a longer focal length of the probe 21 results in a longer distance L during ultrasound examination. Conversely, a shorter focal length of the probe 21 also results in a shorter distance L during ultrasound examination. A suitable aqueous layer W1 for ultrasound examination is one formed so as to contact (span) both the upper surface 20 and the lower surface E2. Preferably, the aqueous layer W1 adheres tightly to both the upper surface 20 and the lower surface E2 due to surface tension. Therefore, the height (thickness) of the aqueous layer W1 differs depending on the focal length of the probe 21. Thus, it is preferable that the hydrophilicity of the upper surface 20 differs depending on the focal length of the probe 21. This makes it easier to form an aqueous layer W1 that contacts both the upper surface 20 and the lower surface E2.

[0038] For example, the longer the focal length of the probe 21, the lower the hydrophilicity of the upper surface 20 of the probe unit 2. By lowering the hydrophilicity of the upper surface 20, the height of the water layer W1 on the upper surface 20 can be increased, and a water layer W1 that contacts both the upper surface 20 and the lower surface E2 can be formed. On the other hand, the shorter the focal length of the probe 21, the higher the hydrophilicity of the upper surface 20 of the probe unit 2. By increasing the hydrophilicity of the upper surface 20, the height of the water layer W1 on the upper surface 20 can be decreased, and when the probe unit 2 reaches the end E3 of the subject E during ultrasound examination, it is possible to suppress water from entering (penetrating) from the joint interface of the subject E. For example, when the focal length is L1, if the contact angle (described later), which is an indicator of hydrophilicity, is θ1, then when the focal length is L2 (longer than L1), the contact angle is θ2 (greater than θ1).

[0039] Figure 6 illustrates the relationship between the hydrophilicity of the upper surface 20 and the height of the water layer W1, and shows the formation state of the water layer W1 when the hydrophilicity is low. As described above, when the focal length is relatively long, there is a limit to how much the height of the water layer W1 can be increased even if the water supply is increased. Therefore, by reducing the hydrophilicity of the upper surface 20 and raising the height of the water layer W1, an appropriate water layer W1 can be formed in the space 10.

[0040] FIG. 7 is a diagram for explaining the relationship between the hydrophilicity of the upper surface 20 and the height of the water layer W1, and is a diagram showing the formation state of the water layer W1 when the hydrophilicity is high. When the focal length is relatively short, by increasing the hydrophilicity of the upper surface 20, a low water layer W1 is formed. If water W is excessively supplied when the hydrophilicity of the upper surface 20 is low, when the probe unit 2 moves to the end E3 of the subject E for ultrasonic inspection maintenance, the water layer W1 may rise and protrude from the end E3. Then, the protruding water W may flow around the bonding interface of the subject E and enter the inside of the subject E. Therefore, in the example of the present disclosure, the water layer W1 is formed low.

[0041] As shown in FIGS. 6 and 7, by adjusting the hydrophilicity of the probe nozzle 22 according to the focal length of the probe 21, the height of the water layer W1 can be finely adjusted. The adjustment of the hydrophilicity may be performed by changing the composition (physical properties) of the hydrophilic film 202, or may be performed by changing the roughness (for example, the arithmetic mean roughness Ra) of the unevenness 102.

[0042] FIG. 8 is a diagram showing the formation state of the water layer W1 when the hydrophilicity of the upper surface 20 is high and the focal length is long. As shown in FIG. 8, since the focal length of the probe 21 is long, the distance L between the probe unit 2 and the subject E becomes long. And because the hydrophilicity of the upper surface 20 is high, even if the water supply amount to the space 10 is increased, a water layer W1 with an appropriate height cannot be formed. That is, when the surface properties of the upper surface 20 are the same, there is a limit to the height of the water layer W1 that can be formed.

[0043] Therefore, when forming the water layer W1, it is conceivable to move the probe unit 2 upward (closer to the subject E), and then align the focal point P with the inspection target portion E1. However, in this case, in order to align the focal point P after forming the water layer W1, the probe unit 2 may need to be moved downward significantly. As a result, the water layer W1 may not be stably maintained in some cases.

[0044] FIG. 9 is a diagram showing the formation state of the water layer W1 when the upper surface 20 has high hydrophilicity and a short focal length. As shown in FIG. 9, by reducing the hydrophilicity of the upper surface 20, the height of the water layer W1 can be increased. Thereby, an appropriate water layer W1 can be formed in the space 10 without moving the probe unit 2 upward. Therefore, in other words, even when forming a water layer W1 having a height that cannot be formed by increasing the water supply amount, by reducing the hydrophilicity (increasing the hydrophobicity) of the upper surface 20, a water layer W1 having a desired height can be formed.

[0045] Step S3 shown in FIG. 1 above is a formation step of forming the water layer W1 in the space 10 by temporarily changing at least one of the height of the probe unit 2 with respect to the subject E or the water supply amount to the space 10 from the height and water supply amount in the subsequent step S4. Note that the subsequent step S4 is when the focal point P of the probe 21 is aligned with the inspection target portion E1 of the subject E in a state where the water layer W1 is formed in the space 10. Also, the temporary change here means, for example, changing (modifying) from these index values to temporarily different values based on the height of the probe unit 2 and the water supply amount to the space 10 at the time of step S4, ultrasonic inspection, etc., and forming the water layer W1. Since the ultrasonic inspection apparatus 1 is an apparatus for ultrasonically inspecting the subject E, these index values are changed from the values at the time of ultrasonic inspection based on the height and water supply amount at the time of the ultrasonic inspection.

[0046] By temporarily changing at least one of the height or the water supply amount, an appropriate water layer W1 for inspection using the ultrasonic wave U propagated through the water layer W1 can be easily formed. Thereby, an appropriate water layer W1 for imaging can be formed.

[0047] In step S3 (formation step), an appropriate water layer W1 is formed so as to contact the upper surface 20 of the probe nozzle 22 and the lower surface E2 of the subject E. By forming it in this way, the ultrasonic wave U can be propagated through the water layer W1 to ultrasonically inspect the subject E.

[0048] Normally, if the water supply is too low, the water layer W1 will not come into contact with the lower surface E2. On the other hand, if the water supply is too high, the water layer W1 will come into contact with the lower surface E2, but during ultrasound examination using the probe unit 2, there is a possibility that water W may enter the area to be examined E1 as described above. Therefore, it is preferable to control both the hydrophilicity of the upper surface 20 and the water supply amount.

[0049] Step S4, shown in Figure 1, is a focusing step performed after step S3. In step S4, the probe unit 2 is driven vertically so that the focus P of the probe 21 aligns with the part to be examined E1. Note that ultrasound U is not transmitted in steps S1 to S3, but is transmitted and received in step S4 for focusing. However, in Figures 6 to 9, ultrasound U is illustrated for illustrative purposes. Step S4 includes steps S41 and S42.

[0050] Figure 10 is a diagram illustrating step S41, showing the state in which the focal point P of the probe 21 is set to a position farther from the probe 21 than the part to be inspected E1. Step S41 shown in Figure 1 is the first step of setting the height of the probe 21 to a position in which the focal point P is farther from the part to be inspected E1 as viewed from the probe 21. When ultrasonic waves U are transmitted from the probe 21 in the state shown in Figure 5, that is, with the water layer W1 properly formed in the space 10, the focal point P where the ultrasonic waves U converge is located above the part to be inspected E1, as shown in Figure 10. The focal point P is the part where the intensity of the ultrasonic waves U is strongest.

[0051] Figure 11 illustrates step S42, showing the state in which the focal point P of the probe 21 is aligned with the part to be examined E1. Step S42 is a second step in which the probe unit 2 is moved downward from its position in step S41 while maintaining the state in which the water layer W1 is formed in the space 10. The downward movement causes the focal point P to align with the part to be examined E1. Furthermore, the downward movement causes the water layer W1 to be stretched rather than compressed (crushed). This suppresses the wetting and spreading of water W due to compression. As a result, when the probe unit 2 reaches the end E3 of the subject E during ultrasound examination, it is possible to suppress excess water W from flowing around to the joint interface of the subject E.

[0052] Steps S41 and S42 allow the formed aqueous layer W1 to be properly maintained, and the position (height) of the focal point P can be adjusted within the range where the aqueous layer W1 is maintained by surface tension. This improves the workability for adjusting the focal point P.

[0053] Figure 12 shows the state when the probe unit 2 reaches the end E3 of the subject E during an ultrasound examination. When a stable aqueous layer W1 is formed in steps S41 and S42 above, surface tension acts between the aqueous layer W1 and the bottom surface E2. For this reason, when performing an ultrasound examination by scanning in the x and y directions with the focal point P aligned with the part to be examined E1, even if the probe unit 2 moves to the end of the subject E, water is less likely to flow around the joint surface of the subject E. This is because, as described above, the surface tension of the water W acting between the aqueous layer W1 and the bottom surface E2 makes it difficult for the aqueous layer W1 to separate from the bottom surface E2.

[0054] Returning to Figures 10 and 11 above, it is preferable to temporarily stop the movement of the probe unit 2 after step S41 (Figure 10) and before step S42 (Figure 11), that is, before moving it downward in step S42. By temporarily stopping the movement, the surface tension formed between the water layer W1 and the lower surface E2 is stabilized, and even if the probe unit 2 is then moved downward, the water layer W1 is less likely to peel off from the lower surface E2. The time for temporary stopping is, for example, 0.1 seconds or more and 2 seconds or less, and should be just a brief moment. In other words, it is preferable not to move it continuously.

[0055] Furthermore, in step S42, after the focus P is aligned with the area to be examined E1, the ultrasound examination is performed.

[0056] Figure 13 illustrates the case where the amount of water supplied to the space 10 between the upper surface 20 and the lower surface E2 is excessive. When the probe unit 2 is located completely below the subject E, the water W between the probe unit 2 and the subject E is compressed by them. Therefore, even if the amount of water supplied is excessive, the water W and the water layer W1 do not affect the subject E.

[0057] However, as shown in Figure 13, if the probe unit 2 reaches the end E3 of the subject E during ultrasound examination and the subject E is not above the water layer W1, then if the water supply is excessive, the water W will rise in the area where the subject E is not present. As a result, the rising water may reach the inspection target part E1, which is the joint interface of the subject E, and enter the joint interface. In such cases, the rise of the water W can be suppressed and its intrusion into the joint interface can be prevented by increasing the hydrophilicity of the upper surface 20 to lower the water layer W1.

[0058] Figure 14 is a cross-sectional view of the hydrophilic film 202. In Figure 14, the upper surface 20 of the probe nozzle 22 is smoothed for the sake of illustration, but in reality, irregularities 201 are formed as described above. The composition, internal structure, etc. of the hydrophilic film 202, which were reserved above, will be described in detail below.

[0059] The film 202 is hydrophilic as described above. Here, hydrophilicity does not mean that it dissolves easily in water W, but rather that it has excellent wettability (ease of wetting of water W) when it comes into contact with water W. There are no particular limitations on the specific degree of hydrophilicity, but for example, hydrophilicity such that the contact angle of water W (pure water, ultrapure water, deionized water, distilled water, etc.) is, for example, 1° to 50°, preferably 10° to 45°, more preferably 15° to 40°, and particularly preferably 20° to 35° is preferred. The contact angle can be measured, for example, by using a probe nozzle 22 having an upper surface 20 coated with film 202, dropping a 50 μm water droplet (a droplet of water W used in the ultrasonic inspection device 1) onto the upper surface 20, and measuring the contact angle of the water droplet using a contact angle meter (model: CA-D) manufactured by Kyowa Interface Science Co., Ltd.

[0060] The specific structure of the film 202 is not particularly limited. The film 202 has, for example, a three-dimensional structure (network structure) in which silicon and oxygen atoms are bonded in a network. A material for the film 202 having such a three-dimensional structure is, for example, silica glass. Having such a three-dimensional structure improves the strength of the film 202 and reduces the risk of physical damage such as delamination. Furthermore, such a three-dimensional structure also has excellent chemical durability, so the film 202 (SiO ２ This can suppress the elution of substances (etc.) into water W through chemical reactions.

[0061] The membrane 202 has voids 203. The presence of voids 203 allows water to penetrate the voids 203 when it comes into contact with the membrane 202, further improving its hydrophilicity. The volume of the voids 203 relative to the total volume of the membrane 202 is not limited to this numerical range, but is, for example, 1% to 50% by volume, preferably 10% to 45% by volume, and particularly preferably 20% to 40% by volume. The larger the volume (amount) of the voids 203, the easier it is for water to enter and the higher the hydrophilicity tends to be, and the smaller the volume of the voids 203, the more difficult it is for water to enter and the lower the hydrophilicity tends to be. The volume of the voids 203 can be measured, for example, by taking a cross-sectional micrograph of the membrane 202 and calculating the volume of the voids 203 from the obtained image.

[0062] The film 202 further contains silica particles 204 (silicon dioxide particles). Since the silica particles 204 contain the same element (silicon) as the silicon in the three-dimensional structure that constitutes the film 202, the silica particles 204 and the film 202 are compatible. For this reason, the inclusion of silica particles 204 can suppress detachment from the film 202. Furthermore, as will be described in detail later, by using silica particles 204 in combination during the formation of the film 202, i.e., during the formation of the three-dimensional structure, some of the silica particles 204 are incorporated into the three-dimensional structure, thereby suppressing the formation of a regular three-dimensional structure and allowing for the formation of voids 203.

[0063] The size of the silica particles 204 is not particularly limited, but for example, it is 1 nm to 100 nm, preferably 5 nm to 70 nm, more preferably 10 nm to 50 nm, and most preferably 10 nm to 20 nm. The size of the silica particles 204 can be determined by, for example, the average particle size measured by a laser diffraction scattering particle size distribution analyzer (e.g., Horiba LA-950V2 particle size analyzer).

[0064] The thickness of the film 202 is not particularly limited, but is, for example, 10 nm to 1000 nm, preferably 25 nm to 500 nm, more preferably 50 nm to 250 nm, and most preferably 75 nm to 150 nm.

[0065] The method for forming the film 202 (the method for manufacturing the film 202) is not particularly limited, but as an example, the following method can be used.

[0066] The film 202 can be formed (manufactured), for example, by applying a coating solution (which is also a paint; hereinafter referred to as the coating solution of this disclosure) to the upper surface of the probe nozzle 22, and then curing the coating solution. The coating solution of this disclosure includes silica particles (silicon dioxide; particles that become the above-mentioned silica particles 204 after the film 202 is formed), a binder that holds the silica particles, and a solvent that disperses or dissolves the silica particles and the binder. The coating solution of this disclosure may also contain any additives other than these. Of these, the binder is preferably an alkoxysilane compound (silica binder) that hardens upon heating to obtain the film 202, and in which the main component (the most abundant component; the same applies hereinafter) of the film 202 is silica.

[0067] The particle size of the silica particles contained in the coating solution of this disclosure can be determined in the same manner as described above for the silica particles 204 (average particle size, etc.).

[0068] The hydrophilicity of silica particles is exhibited, for example, by hydroxyl groups exposed on the surface of the silica particles. For instance, it is thought that when some of the bonds between silicon and oxygen break, hydroxyl groups are exposed, and these exposed hydroxyl groups exhibit hydrophilicity. Therefore, the larger the surface area of ​​silica particles per unit mass, the greater the number of hydroxyl groups exposed on the surface per unit mass. This improves hydrophilicity. The smaller the particle size (i.e., the smaller the particle; the smaller the average particle size), the larger the surface area per unit mass, and thus the stronger the hydrophilicity can be exhibited.

[0069] On the other hand, as the particle size increases, the gaps between the silica particles 204 after the film 202 is formed become wider. As a result, the number (volume) of gaps between the silica particles 204 decreases, and capillary action becomes less likely to occur compared to when smaller silica particles are used. Therefore, as the particle size increases, it becomes more difficult to improve hydrophilicity.

[0070] The density of silica particles is 2.5 g / cm³. ３ ~2.6 g / cm ３ However, the density of silica particles is the density of the solvent (for example, 0.8 g / cm³), which will be discussed later. ３ ~1.0 g / cm ３ It is considerably larger than ). Therefore, silica particles precipitate in the coating solution of this disclosure, especially when the particle size is large. In particular, precipitation is significant when the particle size of the silica particles is 70 nm or larger. For this reason, when the particle size is large, it is preferable to thoroughly stir the coating solution of this disclosure before application to disperse the silica particles throughout the coating solution of this disclosure. Based on the above, the upper limit of the particle size (average particle size) of the silica particles is preferably 50 nm within the above numerical range.

[0071] The above description assumes that the silica particles are spherical. However, some silica particles may be in the form of several to tens of spherical particles linked together (clumps). In such cases, if the particle size of a single spherical particle separated from the clump is 50 nm or less, the dispersibility is sufficient and the particle size is suitable. From this viewpoint as well, for the reasons stated above, the preferred average particle size is 50 nm or less.

[0072] The coating solution of this disclosure contains a silica binder represented by the following structural formula (1). In structural formula (1), the wavy lines on all four sides indicate that the description of the bonds has been omitted.

[0073]

[0074] The silica binder forms the three-dimensional structure described above through polymerization, in which silicon and oxygen atoms are bonded in a network structure. Therefore, the silica binder can be considered an intermediate of the compounds that constitute the film 202. If silica particles are present during polymerization, the silica particles may be incorporated into the polymerization of the silica binder.

[0075] Silica binder is a polymer compound produced by the polymerization of monomers such as tetraethoxysilane. Neither silica particles nor silica binder are soluble in organic solvents. However, it is preferable to use monomers that are soluble in organic solvents.

[0076] Specifically, such monomers include hydrolyzable silicon compounds that transform into silica binders (silica) through hydrolysis. Hydrolyzable silicon compounds are sometimes called silica sols. Silica sols are compounds in which multiple tetraalkoxysilanes undergo partial hydrolysis, removing the alkoxy groups, and multiple molecules form silicon-oxygen-silicon bonds, resulting in polymers with an average molecular weight of several thousand to tens of thousands.

[0077] Silica sol is soluble in alcohol-based organic solvents such as methanol and ethanol. Tetraethoxysilane is preferred as the tetraalkoxysilane that forms the silica sol. By using tetraethoxysilane, reactivity with water is kept low, and curing of the coating solution of this disclosure can be suppressed even when stored for a long period of time in a high-humidity environment. In addition, when curing the coating solution of this disclosure after application, the heat curing time can be shortened, and the thermosetting reaction can proceed rapidly at a relatively low temperature.

[0078] Besides silica sol, which is a polymer of alkoxysilane, other monomers can be used that have three alkoxy groups attached to a silicon atom with four bonding groups in the molecule, and other bonding groups other than alkoxy groups (such as a benzene ring or alkyl chain). However, when such monomers are used, although silica is the main component of film 202, other atoms such as carbon, nitrogen, and sulfur are also included in film 202.

[0079] Specific examples of such compounds include at least one of methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-isocyanatetopropyltrimethoxysilane, 3-isocyanatetopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-mercaptopropyltriethoxysilane.

[0080] The solvent contained in the coating solution of this disclosure may be an inorganic solvent (e.g., water), but an organic solvent is preferred. Among organic solvents, an organic solvent that does not react (e.g., dissolve, swell, etc.) with the probe nozzle 22 that applies the coating solution of this disclosure is preferred. Specifically, for example, an alcohol-based organic solvent is preferred. More specifically, alcohols having 1 to 4 carbon atoms, such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, etc., are preferred. Since these solvents have a boiling point of about 60°C to 120°C, they volatilize quickly after application, which has the advantage of shortening the time required for film formation. Furthermore, by using alcohols with 4 or fewer carbon atoms, hydrolyzable silicon compounds become easier to dissolve, and drying after application can be carried out quickly.

[0081] In addition to these alcohols, cellosolve-based solvents in which one of the hydroxyl groups of ethylene glycol is replaced with a monoalkoxy group are also suitable because they readily dissolve hydrolyzable silicon compounds. When using cellosolve-based solvents, it is preferable to promote the evaporation of the solvent after application using heating, vacuum, or other means.

[0082] The solid components in the coating solution of this disclosure are typically silica particles, silica binder, monomers, etc. Different ratios of these components change the hydrophilicity of the film 202, i.e., the contact angle of the film 202. For example, if the amount of silica particles is relatively high, the hydrophilicity increases and the contact angle decreases. On the other hand, if the amount of silica particles is relatively low, the hydrophilicity decreases and the contact angle increases. Therefore, it is preferable to determine the ratio of these components based on the desired degree of hydrophilicity (magnitude of the contact angle).

[0083] The specific method for forming the film 202 using the coating solution of this disclosure is not particularly limited. Typically, a hydrophilic film 202 can be formed on the upper surface 20 by applying the coating solution of this disclosure to the upper surface 20 and then curing the coating solution.

[0084] Before applying the coating solution of this disclosure, it is preferable to wash the top surface 20 to remove impurities. Washing can be performed using any solvent (water, acetone, hexane, etc.). However, the type of solvent can be arbitrarily selected as long as it does not dissolve or chemically react with the top surface 20. After washing, it is preferable to dry it thoroughly at room temperature (25°C), for example.

[0085] The coating solution of this disclosure can be applied by any application method. For example, a dip coating method can be used. Specifically, after hooking a lifting jig (not shown) into a hole (not shown) provided in the probe nozzle 22, the probe nozzle 22 is inserted so that at least the upper surface 20 is immersed in the dip layer containing the coating solution of this disclosure. Then, by lifting it at a slow speed, for example, 1 mm / sec, the coating solution can be applied to the upper surface 20.

[0086] The pulling speed can be changed depending on the viscosity of the coating solution, the thickness of the film 202, etc. However, in the ultrasonic inspection apparatus 1 of this disclosure, the measurement accuracy tends to decrease as the distance from the upper surface 20 of the probe nozzle 22 to the object E (e.g., semiconductor wafer) increases. Therefore, it is preferable for the film 202 to be thin, and for this reason, it is desirable to pull it up at a speed that allows for the uniform formation of a film 202 with a thickness of 100 nm or less.

[0087] The coating method is not limited to dip coating; for example, spray coating, spin coating, etc., can be selected depending on the shape of the probe nozzle 22, workability, etc.

[0088] The applied coating solution can be dried, for example, by heating. The heating temperature and heating time will vary depending on the material of the probe nozzle 22, including the upper surface 20, but it is preferable to heat it to a temperature high enough that the probe nozzle 22 does not deform. Heating at such a temperature will volatilize the solvent and accelerate the curing reaction of the coating solution.

[0089] However, if the probe nozzle 22 is made of a low-melting-point material such as polyethylene or polypropylene, it is preferable to use a combination of curing by heating and curing at room temperature (e.g., room temperature, 25°C). Specifically, for example, it is preferable to heat the probe nozzle 22 using a constant-temperature bath at 50°C, then remove it from the bath and leave it at room temperature (25°C) for a predetermined time (e.g., one week). By leaving it to stand, polymerization (reaction) between the silica binder and silica particles proceeds further, and the coating liquid hardens, forming a film 202.

[0090] The present disclosure will be explained below with reference to specific examples, but the present disclosure is not limited to these examples. A film 202 was formed, and the drying conditions for the film 202 and the coating liquid of the present disclosure were investigated.

[0091] (Preparation of the coating solution of this disclosure) The coating solution of this disclosure was prepared according to the following method. First, 30 g of silica particles with an average particle size of 10 nm, as measured by a particle size analyzer LA-950V2 manufactured by Horiba, Ltd., 0.5 g of diethylene glycol monoacetate as a dispersant, and 69.5 g of ethanol as an organic solvent were placed in a polypropylene container and stirred to prepare 100 g of a dispersion A of 30% by mass silica particles.

[0092] Next, 7.0 g of tetraethoxysilane, the monomer of the silica binder shown in structural formula (1) above, 0.2 g of acetic acid as a polymerization acid catalyst for tetraethoxysilane, and 92.8 g of ethanol as an organic solvent were placed in a polypropylene container. Then, the tetraethoxysilane was polymerized by stirring at 50°C for 2 hours to produce the silica binder, and after natural cooling to room temperature (25°C), 100 g of dispersion B of 2% by mass of silica binder (the compound shown in structural formula (1) above) was prepared.

[0093] Finally, 10 g of the prepared silica particle dispersion A, 100 g of the silica binder dispersion B, and 140 g of 1-butanol as an organic solvent were placed in a polypropylene container and stirred to prepare 250 g of the coating solution of the present disclosure.

[0094] (Preparation of a test specimen simulating the probe nozzle 22) A test specimen simulating the upper surface 20 of the probe nozzle 22 was prepared according to the following method. First, a plate-shaped test specimen with a longitudinal length of 160 mm, a transverse length of 20 mm, and a thickness of 2 mm was prepared using polyethylene plate material. Next, in order to remove impurities from the surface of the test specimen, the test specimen was washed with ethanol, a polar solvent, then rinsed with hexane, a non-polar solvent, and thoroughly dried at room temperature (25°C).

[0095] A lifting jig was attached to screw holes located at the right and left ends of the longitudinal side (long side) of the test specimen, and the specimen was placed on a dedicated dip coater mounted on a vibration isolation table. A dip tank filled with the coating solution of this disclosure up to the height of the test specimen was placed on the dip coater, and the test specimen was lowered at 10 mm / sec until the entire specimen was immersed in the dip tank. After the entire specimen was immersed, the test specimen was lifted at 1 mm / sec.

[0096] The lifted test specimen was suspended in a constant temperature bath preheated to 50°C for 10 minutes, and then removed from the bath. The removed test specimen was left at room temperature (25°C) for one week to allow the film 202 to fully harden. When the dimensions of the test specimen with film 202 were measured, they were the same as the dimensions of the initially prepared test specimen, and no dimensional changes such as shrinkage were observed.

[0097] Test specimens equipped with the membrane 202 were prepared in the same manner as described above, except that the preheating temperature (holding temperature) of the constant temperature bath and the holding time in the constant temperature bath were varied. The dimensions of the long side of the prepared test specimens were measured, and the length reduced from the dimensions of the long side of the initially prepared test specimen was calculated. The calculated results are shown in Table 1 below. In Table 1, "-" indicates that measurement was not performed.

[0098]

[0099] In Table 1, the vertical column represents the preheating temperature (°C), and the horizontal column represents the holding time (minutes). The numerical value shown at the intersection of the vertical and horizontal columns represents the length (mm) of the long side of the test specimen that has shrunk from the initial test specimen (the test specimen before the formation of film 202). For example, when the holding time was 10 minutes, there was no dimensional change up to a preheating temperature of 50°C (the length shrunk was 0 mm, i.e., there was no deformation). Similarly, when the holding time was 20 minutes or 30 minutes, there was no dimensional change up to a preheating temperature of 50°C. However, at preheating temperatures of 60°C or higher, there was a dimensional change of 1 mm or more when the holding time was 10 minutes or longer. In addition, when the holding time was 60 minutes, there was a dimensional change at preheating temperatures of 50°C or higher, and when the holding time was 90 minutes, there was a dimensional change at preheating temperatures of 45°C or higher.

[0100] The test specimen is a replica of the upper surface 20 of the probe unit 2 provided in the ultrasonic inspection device 1, and is used in the special environment of ultrasonic inspection. Therefore, it is preferable that there is no dimensional change at all, and it was found that the heating temperature and heating time should be 50°C or lower and within 30 minutes.

[0101] (Evaluation of film 202) The contact angle of water W (pure water) with film 202 formed under the above method at a heating temperature of 50°C for a heating time of 10 minutes was evaluated. However, as a reference example, test specimens without film 202 were also prepared. The following four types of test specimens were prepared. The test specimens were prepared in the same manner as the polyethylene test specimens used to obtain the measurement results in Table 1 above, except that the following conditions were different. Test specimen 1: A test specimen consisting only of an unroughed smooth surface (arithmetic mean roughness 0.41 μm) as the top surface 20 (i.e., no film 202 formed). Test specimen 2: A test specimen in which a film 202 was formed on an unroughed smooth surface (arithmetic mean roughness 0.41 μm) as the top surface 20 using the method described in "(Preparation of a test specimen mimicking a probe nozzle 22)". Test specimen 3: A test specimen consisting only of a roughened surface (arithmetic mean roughness 1.93 μm) as the top surface 20 (i.e., no film 202 formed). Test specimen 4: A test specimen in which a film 202 was formed on a roughened surface (arithmetic mean roughness 1.93 μm) as the top surface 20 using a file using the method described in "(Preparation of a test specimen mimicking a probe nozzle 22)".

[0102] The contact angles of test specimens 1 to 4 were measured using a contact angle meter (model: CA-D) manufactured by Kyowa Interface Science Co., Ltd., in accordance with the method of JIS R 3257:1999. Three measurements were taken, and the average of the three measurements was calculated. The calculated average values ​​are shown in Table 2 below.

[0103]

[0104] The results shown in Table 2 indicate that in the absence of the film 202, roughening the smooth surface of the resin increased the contact angle, thus improving hydrophobicity. On the other hand, in the presence of the film 202, forming a hydrophilic film 202 on the roughened surface reduced the contact angle, thus improving hydrophilicity. Therefore, it was found that hydrophilicity can be improved by, for example, creating irregularities on the upper surface 20 of a probe nozzle 22 made of resin (e.g., hydrophobic) and then forming a hydrophilic film 202 on it.

[0105] 1 Ultrasound inspection device 10 Space 102 Irregularities 2 Probe unit 20 Top surface 201 Irregularities 202 Membrane 203 Gap 204 Silica particles 21 Probe 22 Probe nozzle 23 Inlet 24 Water channel 25 Water inlet 3 Scanning measurement device 4 Control device E Subject E1 Area to be inspected E2 Bottom surface E3 End L Distance P Focus S1 Step (Movement step) S2 Step (Supply start step) S3 Step (Formation step) S4 Step (Focusing step) S41 Step (First step) S42 Step (Second step) U Ultrasound W Water W1 Water layer

Claims

1. A method for controlling a probe unit of an ultrasound examination apparatus that performs ultrasound examination by forming a layer of water in the space between the tip of an ultrasound probe and a subject, comprising: a movement step of moving a probe unit, which comprises a probe, a probe nozzle covering the probe, and an inlet for supplying water to the probe nozzle, downward of the subject so that the distance between the lower surface of the subject and the upper surface of the probe unit is a predetermined distance; a supply start step of starting to supply water to the space formed between the lower surface of the subject and the upper surface of the probe nozzle through the inlet and a water supply port for supplying water from the probe nozzle to the subject; and a formation step of temporarily changing at least one of the height of the probe unit relative to the subject or the amount of water supplied to the space from the height and amount of water supplied when the probe is focused on the part of the subject to be examined while a layer of water is formed in the space, thereby forming a layer of water in the space.

2. A method for controlling a probe unit of an ultrasonic inspection apparatus according to claim 1, comprising a focusing step performed after the forming step, wherein the focusing step includes: a first step of setting the height of the probe to a position where the focus is further away from the object to be inspected than the object to be inspected as viewed from the probe; and a second step of moving the probe unit downward from the position of the probe unit in the first step, while maintaining the state in which a layer of water has been formed in the space, to align the focus with the object to be inspected.

3. A method for controlling the probe unit of an ultrasonic inspection apparatus according to claim 2, characterized in that the movement of the probe unit is temporarily stopped after the first step and before the second step.

4. A method for controlling the probe unit of an ultrasonic inspection apparatus according to claim 1, characterized in that the hydrophilicity of the upper surface of the probe nozzle differs depending on the focal length of the probe.

5. A method for controlling the probe unit of an ultrasonic inspection apparatus according to claim 4, characterized in that the longer the focal length of the probe, the lower the hydrophilicity of the upper surface of the probe nozzle, and the shorter the focal length of the probe, the higher the hydrophilicity of the upper surface of the probe nozzle.

6. A method for controlling a probe unit of an ultrasonic inspection apparatus according to claim 1, characterized in that, in the forming step, the water layer is formed so as to be in contact with the upper surface of the probe nozzle and the lower surface of the specimen.

7. A probe unit for an ultrasonic testing apparatus used in a control method for the probe unit of an ultrasonic testing apparatus according to claim 1, characterized in that at least a portion of the surface of the probe unit facing the subject has irregularities formed on it.

8. A probe unit for an ultrasonic testing apparatus according to claim 7, characterized in that a hydrophilic film is formed on at least the portion of the surface facing the specimen on which the irregularities are formed.

9. A probe unit for an ultrasonic inspection apparatus according to claim 8, wherein the hydrophilic membrane has a three-dimensional structure in which silicon and oxygen atoms are bonded in a mesh-like manner.

10. A probe unit for an ultrasonic inspection apparatus according to claim 9, wherein the hydrophilic membrane further comprises silica particles.

11. A probe unit for an ultrasonic inspection apparatus according to claim 7, characterized in that the portion on which the irregularities are formed has a roughness such that individual irregularities cannot be seen by a person with the naked eye.

12. A probe unit for an ultrasonic testing apparatus according to claim 7, characterized in that at least one of the members of the probe unit that forms the surface facing the specimen is made of resin.

13. An ultrasonic inspection apparatus comprising: a probe unit of the ultrasonic inspection apparatus described in claim 7; a scanning measuring device for driving the probe unit in a predetermined direction; and a control device for controlling the operation of the probe unit and the scanning measuring device.

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