TWI733208B - Ultrasonic probe and manufacturing method thereof - Google Patents

Abstract

An ultrasonic probe includes a Micromachined Ultrasonic Transducer (MUT) substrate, a conductive adhesive, a circuit board and an acoustic transmission medium. The MUT substrate has an emitting surface. The conductive adhesive surrounds an area on the emitting surface and has a first recess corresponding to the area. The circuit board has an opening, the circuit board is disposed on the conductive adhesive and the opening corresponds to the area, and the circuit board has a second recess. The acoustic transmission medium is formed within the first recess and the second recess.

Description

Ultrasonic probe and its manufacturing method

The present invention relates to an ultrasonic probe and its manufacturing method, and more particularly to an ultrasonic probe with conductive glue and its manufacturing method.

The conventional ultrasonic probe includes a circuit board and a sound wave generating array. At present, most of the bonding wires are used to laterally bridge the circuit board and the sound wave generating array to electrically connect the sound wave generating array and the circuit board. However, the use of the wire bonding method requires special consideration of the operability of the wire bonding tool head (such as whether there is enough operating space) and the bonding wire usually has a length, which constitutes a part of the impedance.

Therefore, there is a need to provide an ultrasonic probe and a manufacturing method thereof that can improve the aforementioned problems.

The embodiment of the present invention provides an ultrasonic probe and a manufacturing method thereof, which can improve the above-mentioned problems.

An embodiment of the present invention provides an ultrasonic probe. The ultrasonic probe includes a micromechanical ultrasonic transducer substrate, a conductive glue, a circuit board and a sound wave transmission medium. The substrate of the micromechanical ultrasonic transducer has an emitting surface. Conductive glue surrounds one of the emitting surface Area, and the corresponding area has a first recess. The circuit board has an opening, the circuit board is disposed on the conductive glue and the opening corresponds to an area, and the circuit board has a second recess. The acoustic wave transmission medium is formed in the first concave portion and the second concave portion.

The delivery system includes a method for manufacturing an ultrasonic probe proposed in another embodiment of the present invention. The manufacturing method includes the following steps: forming a conductive glue on a emitting surface of a micromechanical ultrasonic transducer substrate to surround an area, and forming a first recess corresponding to the area; disposing a circuit board on the conductive glue, the circuit board has An opening, a region corresponding to the opening forms a second recess above the first recess; and, a sound wave transmission medium is formed in the first recess and the second recess.

In order to have a better understanding of the above and other aspects of the present invention, the following specific examples are given in conjunction with the accompanying drawings to describe in detail as follows:

10: Controller

100, 200: Ultrasonic probe

110, 210: Micromachined ultrasonic transducer substrate

110e: outer side

110g: ground wire

110s: signal line

110u: launch surface

111: Acoustic wave generation array

1111: Sound wave generating unit

1111s: signal cable

1111g: Ground connection wire

1111r: resonant cavity

1112: resonance film

120, 220: conductive adhesive

120r, 220r: the first recess

130: circuit board

130a: opening

130g: Grounding pad

130s: signal pad

130r: second recess

140: Acoustic transmission medium

150: cover

160: package body

212: Retaining Wall

221: conductive rubber pad

C1: Control signal

E1: Sound wave emission direction

R1: area

FIG. 1A is a top view of an ultrasonic probe according to an embodiment of the invention.

Figure 1B shows a cross-sectional view of the ultrasonic probe of Figure 1 along the direction 1B-1B'.

FIG. 2A is a top view of an ultrasonic probe according to another embodiment of the present invention.

Figure 2B shows a cross-sectional view of the ultrasonic probe of Figure 2A along the direction 2B-2B'.

Figure 2C shows a cross-sectional view of the ultrasonic probe of Figure 2A along the direction 2C-2C'.

Figures 3A~3F show the manufacturing process of the ultrasonic probe shown in Figure 1A.

Figures 4A~4C show the manufacturing process of the ultrasonic probe in Figure 2A.

In order to have a better understanding of the above-mentioned and other aspects of the present invention, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

Please refer to FIGS. 1A and 1B. FIG. 1A is a top view of an ultrasonic probe 100 according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view of the ultrasonic probe 100 of FIG. 1 along the direction 1B-1B' .

As shown in Figures 1A and 1B, the ultrasonic probe 100 includes a micromachined ultrasonic transducer (Micromachined Ultrasonic Transducer, MUT) substrate 110 (the micromachined ultrasonic transducer substrate 110 in Figure 1A is drawn with thick lines), The conductive glue 120, the circuit board 130, the acoustic wave transmission medium 140, the cover plate 150 and the package body 160. The micromechanical ultrasonic transducer substrate 110 has an emitting surface 110u. The conductive adhesive 120 surrounds the region R1 of the emitting surface 110u, and the corresponding region R1 has a first recess 120r. The circuit board 130 has an opening 130a, the circuit board 130 is disposed on the conductive adhesive 120 and the opening 130a corresponds to the region R1, and the circuit board 130 has a second recess 130r. In this way, the micromachined ultrasonic transducer substrate 110 can be electrically connected to the circuit board 130 through the conductive glue 120. In detail, the micromachined ultrasonic transducer substrate 110 can be electrically connected to the circuit board 130 without passing through a bonding wire.

The micromachined ultrasonic transducer substrate 110 further includes an acoustic wave generating array 111 and at least one wire, such as at least one ground wire 110g and at least one signal wire 110s. The acoustic wave generating array 111, the ground line 110g, and the signal line 110s are formed on the emitting surface 110u. The acoustic wave generating array 111 includes at least one acoustic wave generating unit 1111, wherein a ground line 110g and a signal line 110s are connected to a corresponding acoustic wave generating unit 1111 and extend to the edge of the emitting surface 110u. The "edge" here is, for example, the area outside the acoustic wave generating array 111, and its range can extend to the outer surface 110e of the micromachined ultrasonic transducer substrate 110, for example. However, the embodiment of the present invention is not limited by this.

As shown in FIG. 1B, each acoustic wave generating unit 1111 includes at least one resonant cavity 1111r and at least one resonant film 1112, and each resonant film 1112 is formed on the emitting surface 110u and covers the resonant cavity 1111r. Taking the control of a sound wave generating unit 1111 as an example, the control signal C1 of a controller 10 can be transmitted to the signal line 110s through the circuit board 130, and then through the signal connection line 1111s and the ground connection line 1111g connected to each resonance film 1112, Return to the controller 10 via the ground wire 110g and the circuit board 130. The control signal C1 can control all the resonance films 1112 of each sound wave generating unit 1111 to oscillate up and down to emit ultrasonic waves. In addition, depending on the sound wave focusing characteristics, different sound wave generating units 1111 can be controlled by different control signals C1, such as control signals C1 with different delay times, so that all sound wave generating units 1111 focus on the same area, like a point.

In addition, the resonant cavity 1111r, the resonant film 1112, the signal connection line 1111s, and the ground connection line 1111g can be formed by a semiconductor process, where the semiconductor process includes, for example, photolithography technology, coating technology, and/or any other technology that can form the acoustic wave generating array 111 Semiconductor technology

The conductive adhesive 120 is located between the micromechanical ultrasonic transducer substrate 110 and the circuit board 130 along the acoustic wave emission direction E1, and is electrically connected to the micromechanical ultrasonic transducer substrate 110 and the circuit board 130. The conductive adhesive 120 allows electrical transmission in a Z axis (the Z axis is, for example, approximately parallel to the sound wave emission direction E1), but does not allow electrical transmission in the X and Y axis (e.g., approximately perpendicular to the Z axis). Therefore, even if the conductive adhesive 120 is a continuously extending conductive adhesive, the two adjacent signal lines 110s will not be electrically short-circuited through the conductive adhesive 120 and the two adjacent ground lines 110g will not be electrically short-circuited through the conductive adhesive 120. In this embodiment, the conductive The glue 120 is an anisotropic conductive film (ACF), or other conductive materials that only allow electrical transmission in the Z-axis. In addition, one of the illustrated X axis and Y axis is, for example, the long axis emission direction of the ultrasound probe 100, and the other of the X axis and Y axis is, for example, the short axis emission direction of the ultrasound probe 100.

The circuit board 130 is, for example, a flexible print circuit (FPC), but the embodiment of the present invention is not limited thereto. The circuit board 130 is disposed on the conductive adhesive 120. The circuit board 130 includes at least one pad, such as at least one ground pad 130g and at least one signal pad 130s. The aforementioned conductive adhesive 120 is located between the ground wire 110g of the micromachined ultrasonic transducer substrate 110 and the ground pad 130g of the circuit board 130, and is located between the signal line 110s of the micromachined ultrasonic transducer substrate 110 and the signal of the circuit board 130 Pad between 130s. In this embodiment, each grounding pad 130g and the corresponding grounding wire 110g overlap up and down and the two are electrically connected through the conductive adhesive 120 located therebetween, and each signal pad 130s and the corresponding signal line 110s are overlapped up and down and the two are electrically connected through the conductive adhesive 120 located therebetween. The conductive glue 120 in between is electrically connected. In this way, the ground wire 110g and the signal wire 110s of the micromachined ultrasonic transducer substrate 110 can be electrically connected to the ground pad 130g and the signal pad 130s of the circuit board 130 without the need for bonding wires.

The acoustic wave transmission medium 140 is formed in the first recess 120r and the second recess 130r. For example, the acoustic wave transmission medium 140 fills at least a part of the first recess 120r and the second recess 130r. The acoustic wave transmission medium 140 is, for example, silicone oil, glycerin, or other non-conductive media that can transmit acoustic waves. The acoustic wave transmission medium 140 can help the ultrasonic waves generated by the acoustic wave generation array 111 to be transmitted. As shown in Figure 1A, the conductive adhesive 120 has a closed ring shape, so that the first recess 120r is not connected to the outer surface of the conductive adhesive 120, and the circuit board 130 has a closed ring shape, so that the second recess 130r is not connected to the outer surface of the circuit board 130. Connected. in this way, The acoustic wave transmission medium 140 located in the first concave portion 130r and the second concave portion 140r will not leak laterally from the conductive adhesive 120 and the circuit board 130 to the ground.

In addition, as shown in FIG. 1B, the second recess 130r and the first recess 120r substantially overlap, such as at least partially overlap. In one embodiment, the size of the second recess 130r (such as the top view area) may be less than or substantially equal to the size (such as the top view area) of the first recess 120r, but the size of the second recess 130r is also larger than the size of the first recess 120r.

The cover 150 is disposed on the circuit board 130 and covers the opening 130a to cover the first recess 120r and the second recess 130r, which can prevent the acoustic wave transmission medium 140 in the first recess 120r and the second recess 130r from leaking from the opening 130a. In addition, although not shown in the figure, the ultrasonic probe 100 further includes an adhesive layer formed between the cover 150 and the circuit board 130 to bond the cover 150 and the circuit board 130. In summary, the acoustic wave transmission medium 140 is enclosed in the first recess 120r and the second recess 130r by the conductive glue 120, the circuit board 130 and the cover 150. The cover 150 allows sound waves to pass through, and has a sound wave penetration rate of, for example, 80%, 85%, 90%, or 95% or more. In an embodiment, the cover 150 may be a light-transmitting or non-light-transmitting cover. In terms of material, the material of the cover plate 155 includes resin, such as polyurethane.

As shown in FIG. 1B, the package body 160 covers the micromachined ultrasonic transducer substrate 110, the conductive adhesive 120, a part of the circuit board 130, the acoustic wave transmission medium 140 and the cover 150. The other part of the circuit board 130 protrudes from the package body 160 to be electrically connected to the controller 10. The material of the package body 160 includes Novolac-based resin, epoxy-based resin, silicone-based resin or other suitable coating agents. The package body 160 may also include a suitable filler, such as powdered silicon dioxide. In addition, several packaging technologies can be used to form the package body 160, For example, it is compression molding, liquid encapsulation, injection molding, or transfer molding.

Please refer to FIGS. 2A to 2C. FIG. 2A is a top view of an ultrasonic probe 200 according to another embodiment of the present invention, and FIG. 2B is a cross-sectional view of the ultrasonic probe 200 of FIG. 2A along the direction 2B-2B' , And Figure 2C shows a cross-sectional view of the ultrasonic probe 200 of Figure 2A along the direction 2C-2C'.

The ultrasonic probe 200 includes a micromechanical ultrasonic transducer substrate 210 (the micromechanical ultrasonic transducer substrate 210 in Figure 2A is drawn with thick lines), conductive glue 220, a circuit board 130, an acoustic wave transmission medium 140, and a cover 150 And package body 160. The micromachined ultrasonic transducer substrate 210 has an emitting surface 110u, a sound wave generating array 111, at least one retaining wall 212, and at least one wire, such as at least one ground wire 110g and at least one signal wire 110s. The acoustic wave generating array 111, the ground line 110g, the signal line 110s, and the retaining wall 212 are formed on the emitting surface 110u. The acoustic wave generating array 111 includes at least one acoustic wave generating unit 1111, wherein a ground line 110g and a signal line 110s are connected to a corresponding acoustic wave generating unit 1111 and extend to the edge of the emitting surface 110u.

The conductive adhesive 220 includes a plurality of separated conductive adhesive pads 221. Each conductive rubber pad 221 covers the corresponding ground line 110g or the corresponding signal line 110s. In this embodiment, the electrical transmission of the conductive adhesive 220 is non-directional, that is, electrical transmission along the Z-axis, X-axis, and Y-axis is allowed. Since the plurality of conductive adhesive pads 221 are separated from each other, even if the electrical transmission of the conductive adhesive 220 is non-directional, the two adjacent conductive adhesive pads 221 will not be electrically short-circuited. In one embodiment, the conductive glue 220 is, for example, silver glue, but it can also be other conductive materials.

As shown in Figures 2A and 2C, the conductive adhesive pads 221 of the conductive adhesive 220 are distributed on two opposite edges of the emitting surface 110u of the micromachined ultrasonic transducer substrate 210, and the two retaining walls 212 are respectively located on the emitting surface 110u. On the other two edges, a number of conductive rubber pads 221 and two retaining walls 212 surround the first concave portion 220r, and the first concave portion 220r exposes the acoustic wave generating array 111, such as exposing all the acoustic wave generating units 1111. The circuit board 130 has a second recess 130r. The acoustic wave transmission medium 140 is located in the first recess 220r and the second recess 130r. Due to the configuration of the retaining wall 212, the acoustic wave transmission medium 140 located in the first recess 220r and the second recess 130r can be prevented from leaking. In addition, since several separate conductive rubber pads 221 are arranged adjacently (but not in contact), they also generate a certain leakage resistance to the acoustic wave transmission medium 140 located in the first recess 220r and the second recess 130r, which can reduce the external leakage resistance. Leakage or even no leakage. In addition, a non-conductive material can also be filled between the separated conductive rubber pads 221, which can prevent two adjacent conductive rubber pads 221 from short-circuiting and prevent the acoustic wave transmission medium 140 from leaking. In an embodiment, the retaining wall 212 and the plate body of the micromachined ultrasonic transducer substrate 210 are integrally formed. In addition, the retaining wall 212 is, for example, an insulating retaining wall.

As shown in FIG. 2B, the circuit board 130 is disposed on the conductive adhesive 220. The circuit board 130 includes at least one pad, such as at least one ground pad 130g and at least one signal pad 130s. In this embodiment, each conductive rubber pad 221 is located between the wire of the corresponding micromechanical ultrasonic transducer substrate 210 and the pad of the circuit board 130 along the acoustic wave emission direction E1, and is electrically connected to the corresponding wire and the pad. pad. For example, each conductive rubber pad 221 is located between the corresponding signal line 110s and the signal pad 130s along the sound wave emission direction E1 and is electrically connected to the corresponding signal line 110s and the signal pad 130s, and is located between the corresponding ground line 110g and the ground The pads 130g are electrically connected to the corresponding ground wire 110g and the ground pad 130g.

Please refer to Figures 3A to 3F, which shows the manufacturing process diagram of the ultrasonic probe 100 in Figure 1A.

As shown in Figure 3A, a micromachined ultrasonic transducer substrate 110 is provided, wherein the micromachined ultrasonic transducer substrate 110 includes an emitting surface 110u, an acoustic wave generating array 111, at least one retaining wall 212, and at least one wire, such as at least One ground wire 110g and at least one signal wire 110s. The acoustic wave generating array 111 includes at least one acoustic wave generating unit 1111, a ground line 110g and a signal line 110s extending from the corresponding acoustic wave generating unit 1111 to the edge of the emitting surface 110u.

As shown in FIGS. 3B1 and 3B2, for example, a coating technique can be used to form a conductive adhesive 120 on the emitting surface 110u of the micromachined ultrasonic transducer substrate 110 and surround the area R1. The conductive glue 120 forms a first recess 120r corresponding to the region R1. The first recess 120r exposes the acoustic wave generating array 111. As shown in the figure, the conductive adhesive 120 covers a part of each ground line 110g and a part of each signal line 110s.

As shown in FIG. 3C, the circuit board 130 is disposed on the conductive adhesive 120. The circuit board 130 has an opening 130a. The opening 130a corresponds to the region R1 to form a second recess 130r above the first recess 120r.

As shown in FIG. 3D, an injection technique can be used, for example, to form the acoustic wave transmission medium 140 in the first recess 120r and the second recess 130r. For example, the acoustic wave transmission medium 140 fills at least a part of the first recess 120r and the second recess 130r.

As shown in FIG. 3E, the cover 150 is configured to cover the opening 130a of the circuit board 130, wherein the cover 150 covers the first recess 120r and the second recess 130r. Although not shown, an adhesive layer may be formed between the cover 150 and the circuit board 130 to The relative position between the cover 150 and the circuit board 130 is fixed.

As shown in Figure 3F, for example, compression molding, liquid encapsulation, injection molding or transfer molding can be used to form a package body 160 covering a part of the micromachined ultrasonic transducer substrate 110, conductive adhesive 120, circuit board 130, and The cover 150 is used to form the ultrasonic probe 100. Another part of the circuit board 130 protrudes from the package body 160 to be electrically connected to the controller 10 (the controller 10 is shown in FIG. 1B).

Please refer to Figures 4A to 4C, which shows the manufacturing process diagram of the ultrasonic probe 200 in Figure 2A.

As shown in FIG. 4A, a micromachined ultrasonic transducer substrate 210 is provided, wherein the micromachined ultrasonic transducer substrate 110 includes an emitting surface 110u, an acoustic wave generating array 111, at least one retaining wall 212, and at least one wire, such as at least One ground wire 110g and at least one signal wire 110s. The acoustic wave generating array 111 includes at least one acoustic wave generating unit 1111, and a ground line 110g and a signal line 110s extend from the corresponding acoustic wave generating unit 1111 to the edge of the emitting surface 110u. As shown in the figure, two retaining walls 212 are respectively formed on two opposite edges of the emitting surface 110u.

As shown in FIG. 4B, for example, a coating technique can be used to form the conductive adhesive 120 on the emitting surface 110u of the micromachined ultrasonic transducer substrate 210, for example, on the other two opposite edges of the emitting surface 110u. The second retaining wall 212 and the conductive adhesive 120 surround the region R1, and the corresponding region R1 forms a first recess 120r. The first recess 120r exposes the acoustic wave generating array 111. As shown in the figure, the conductive adhesive 120 covers a part of each ground line 110g and a part of each signal line 110s.

As shown in 4C, for example, cutting technology can be used to The glue 220 is cut into several separate conductive glue pads 221, wherein each ground wire 110g is covered by a corresponding conductive glue pad 221 and each signal line 110s is covered by a corresponding conductive glue pad 221. Since the plurality of conductive adhesive pads 221 are separated from each other, even if the electrical transmission of the conductive adhesive 220 is non-directional, the two adjacent conductive adhesive pads 221 will not be electrically short-circuited. In addition, the aforementioned cutting step can be accomplished by using a knife or a laser, for example.

The manufacturing steps of the ultrasonic probe 200 are similar to the corresponding manufacturing steps of the ultrasonic probe 100, and will not be repeated here.

In summary, although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention belongs can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to those defined by the attached patent application scope.

10: Controller

100: Ultrasonic probe

110: Micromachined ultrasonic transducer substrate

110g: ground wire

110s: signal line

110u: launch surface

1111: Sound wave generating unit

1111s: signal cable

1111g: Ground connection wire

1111r: resonant cavity

1112: resonance film

120: conductive adhesive

120r: the first recess

130: circuit board

130a: opening

130g: Grounding pad

130s: signal pad

130r: second recess

140: Acoustic transmission medium

150: cover

160: package body

C1: Control signal

E1: Sound wave emission direction

R1: area

Claims (3)

A manufacturing method of an ultrasonic probe includes: forming a conductive adhesive on a transmitting surface of a micromechanical ultrasonic transducer substrate and surrounding an area, wherein the conductive adhesive forms a first recess corresponding to the area; and arranging a circuit The board is on the conductive adhesive, the circuit board has an opening, and the opening corresponding area forms a second recess above the first recess; and a sound wave transmission medium is formed in the first recess and the second recess. The manufacturing method described in item 1 of the scope of patent application further includes: arranging a cover plate to cover the opening of the circuit board, wherein the cover plate covers the first concave portion and the second concave portion. The manufacturing method described in item 1 of the scope of patent application, wherein the micromachined ultrasonic transducer substrate includes a plurality of sound wave generating units and a plurality of wires, each of the wires is connected to the corresponding sound wave generating unit, and the circuit board is more It includes a plurality of contact pads, and the conductive adhesive is anisotropic conductive adhesive; in the step of arranging the circuit board on the conductive adhesive, the conductive adhesive electrically connects the corresponding wire and the contact pad.

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