close

Вход

Забыли?

вход по аккаунту

?

DESCRIPTION JP2002027594

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2002027594
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the
application technology of ultrasonic flaw detection, and more particularly to an ultrasonic probe
suitable for acquiring a tomographic image and a method of manufacturing the same.
[0002]
2. Description of the Related Art An ultrasonic tomographic image display apparatus is used in
various fields such as medical diagnosis and internal flaw detection of a structure because of
advantages such as small size, easy movement, and excellent operability. . An example of the
structure of this ultrasonic tomographic image display apparatus is shown in FIG.
[0003]
An array-type ultrasonic probe 600 for transmitting and receiving ultrasonic waves is connected
to the ultrasonic tomographic image display apparatus main body 500 via a cable 700. The
ultrasonic tomographic image display main body 500 is equipped with a monitor 501, a signal
processing system 502 for converting the output from the ultrasonic probe 600 into luminance
information on the monitor 501, and the like.
13-04-2019
1
[0004]
The ultrasonic probe 600 has two wiring boards 630 and 660.
[0005]
On one wiring board 660, a changeover switch circuit 661 connected in series to each of the
piezoelectric ceramic vibrators on the other wiring board 630 and other circuits (memory, buffer,
etc.) 662 are mounted. There is.
Although these circuits 661 and 662 may be provided in the signal processing system of the
ultrasonic tomographic image display apparatus main body 500, in order to prevent signal delay
and signal attenuation in the cable 700, usually, as much as possible , And integrated on the
circuit mounting board of the ultrasonic probe 600.
[0006]
As shown in FIG. 6, a plurality of strip-shaped piezoelectric ceramic vibrators 631 are fixed side
by side on the other wiring board 630 (circuit mounting board). More specifically, one of the
electrodes 631 a and 631 b on both surfaces of each piezoelectric ceramic vibrator 631 is joined
to the electrode 632 on the electrode surface 630 a side of the wiring substrate 630 with a
solder 633. Then, one ground electrode plate 635 is attached to the other electrode 631 b of all
the piezoelectric ceramic vibrators 631 with a conductive adhesive 634. Reference numeral 636
is an acoustic matching layer attached to the ground electrode plate 635, 637 is an insulator
filled between the piezoelectric ceramic vibrators 631, and 638 is a back surface 630b of the
wiring substrate 630 (electrode It is an absorption layer for absorbing the sound wave from
surface 630b opposite to surface 630a.
[0007]
The array structure of the piezoelectric ceramic vibrators 631 on the wiring substrate 630
includes a 1D (Dimensional) array and a 2D array (Dimensional).
[0008]
13-04-2019
2
In the case of an ultrasonic probe of an array structure called a 1D array (hereinafter referred to
as a 1D array probe), a plurality of piezoelectric ceramic vibrators 631 are arranged in the plane
of the wiring substrate 630 at a predetermined pitch. Aligned in a row.
According to this 1D array probe, it is possible to obtain a tomographic image of an observation
target by electronic scanning by switching of the changeover switch circuit 661.
[0009]
In the case of an ultrasonic probe of an array structure called a 2D array (hereinafter referred to
as a 2D array probe), a plurality of piezoelectric ceramic vibrators 631 are arranged in the plane
of the wiring substrate 630. Arranged in a matrix of dimensions. According to this 2D array
probe, it is possible to obtain a three-dimensional image of an observation object by electronic
scanning by switching of the changeover switch circuit 661. In addition, the technique regarding
this 2D array probe is described in 1996 IEEE ULTRASONICS SYMPOSIUM pp1523-pp1526,
1996 IEEE ULTRASONICS SYMPOSIUM pp 1573-pp1576. For example, the latter document
describes a 2D array probe in which 4096 piezoelectric ceramic vibrators (0.22 mm wide × 0.22
mm long) are arranged in a 64 × 64 matrix with a 0.3 mm pitch. There is.
[0010]
Problem to be Solved by the Invention In the ultrasonic probe, high-density loading of the
vibrator is regarded as an important problem from the viewpoint of downsizing of the ultrasonic
probe and improvement of the resolution of the image. There is. In particular, for 2D array
probes, the demand for high-density loading of transducers is high.
[0011]
However, in view of the reliability (connection accuracy, connection strength, etc.) of the soldered
portion between the wiring substrate and the vibrator, in the above-described conventional probe
structure (see FIG. 6), the 1D array probe and Both 2D array probes have limitations in oscillator
miniaturization. Further, when the vibrator is miniaturized, it is also necessary to increase the
density of the wiring substrate on which the vibrator is mounted.
13-04-2019
3
[0012]
An object of the present invention is to provide an ultrasonic probe having a structure optimum
for high density mounting of transducers and a method of manufacturing the same. Another
object of the present invention is to provide an ultrasonic tomographic image display apparatus
having the ultrasonic probe.
[0013]
SUMMARY OF THE INVENTION In order to solve the above problems, in the present invention, a
piezoelectric thin film is grown as the piezoelectric element on a semiconductor element which
turns on and off voltages applied to a plurality of piezoelectric elements. did.
[0014]
Although one embodiment of the present invention will be specifically described in the following,
the matters included in the configurations listed there have as many degrees of freedom as
possible, and any one of the combinations is It shall constitute the invention.
Therefore, for example, a form in which a part of the configuration described as one embodiment
of the present invention is appropriately deleted is also one of the embodiments of the present
invention.
[0015]
Also, each item included in the configuration specifically shown in the following can be replaced
by the same other configuration in function, and as a means specified by the same function It can
be expressed comprehensively.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment according to the
present invention will be described with reference to the attached drawings.
[0017]
13-04-2019
4
First, an ultrasonic probe according to the present embodiment will be described with reference
to FIGS. 1 and 2. FIG.
However, here, a 2D probe is taken as an example.
[0018]
As shown in FIG. 1, the ultrasonic probe 100 includes a circuit mounting board 110, an
electroacoustic transducing layer 130 including a plurality of transducers 131 (piezoelectric thin
films), memory and other circuit elements (not shown). A semiconductor element 120 in which a
plurality of changeover switch circuits (121 in FIG. 2) connected in series to each of the vibrators
131 are built in, a connector 111 to which a cable 111a from an ultrasonic image display
apparatus is connected, have.
[0019]
The semiconductor element 120, the connector 111, and the memory and other circuit elements
are mounted on the top wiring layer 110a of the circuit mounting substrate 110, respectively.
Here, although the semiconductor element 120 and the circuit mounting substrate 110 are
electrically connected by a flip chip method, the circuit mounting substrate is formed on the back
surface 120 a of the semiconductor element 120 (surface opposite to the circuit mounting
substrate 110). An electrode pad for connection to the electrode pad 110 may be formed, and
the semiconductor element 120 and the circuit mounting substrate 110 may be electrically
connected by a wire bonding method.
[0020]
In the semiconductor element 120, in addition to the plurality of changeover switch circuits 121,
lead wires from the contacts (121a and 121b in FIG. 2) of the plurality of switch circuits 121, a
plurality of electrodes connected to the respective lead wires (circuit mounting And the like are
fabricated, including the aforementioned electrodes soldered to the electrode pads of the
substrate 110.
13-04-2019
5
The lead wire (122 in FIG. 2) from one of the contacts 121b of each changeover switch circuit
121 merges into one wire (122a in FIG. 2) and is soldered to the electrode pad of the circuit
mounting substrate 110 It is connected to one of the electrodes. Thus, the number of connection
points between the semiconductor element 120 and the circuit mounting substrate 110 can be
reduced by sharing the lead wiring from one of the contacts 121 b from all the switching circuit
circuits 121.
[0021]
Further, a plurality of electrodes connected to lead wires (123 in FIG. 2) from the other contacts
(121a in FIG. 2) of each changeover switch circuit 121 are n rows and m columns (here, in the
back surface 120b of the semiconductor element). For example, they are arranged in a matrix of
3 × 3) as an example. And the electroacoustic transducing layer 130 is formed in this back
surface 120a.
[0022]
In the electroacoustic layer 130, drive electrodes 132 respectively formed on the respective
electrodes on the back surface 120a of the semiconductor element 120, piezoelectric thin films
131 formed respectively on the respective drive electrodes 132 as vibrators, and all piezoelectric
thin films A ground electrode 134 (an electrode for applying a reference potential) formed in
common to 131, an insulating layer 133 filled between each drive electrode 131 and the ground
electrode 134, and formed on the ground electrode 134 as the outermost layer An acoustic
matching layer 135 is included. The acoustic matching layer 135 is for matching the acoustic
impedance between each of the transducers 131 and the subject (for example, a living body or
the like).
[0023]
As described above, according to the probe structure of the present embodiment, the drive
electrode 132 and the piezoelectric thin film 131 are sequentially formed on the electrodes of
the semiconductor element 120 including the plurality of changeover switch circuits 121. Since
the soldering is not used for the connection of the vibrator, the reliability of the connection can
13-04-2019
6
be maintained even if the vibrator is miniaturized. Of course, even in the case where a transducer
having the same size as the ultrasonic probe described in the section of the related art is
mounted, the effect of improving the reliability of the connection of the transducer can be
obtained.
[0024]
Further, the lead-out wiring 123 from the contact point 121a of each changeover switch circuit
121 is formed on the semiconductor substrate using the semiconductor process technology.
Therefore, a submicron wiring pitch can be realized.
[0025]
As described above, according to the probe structure in accordance with the present
embodiment, the two factors that impede the high density mounting of the fine vibrator are
solved, so that the height of the fine vibrator is high. It is possible to realize density mounting.
Then, by mounting a fine transducer at a high density by this probe structure, it is possible to
miniaturize the ultrasonic probe and improve the resolution of the ultrasonic image.
[0026]
Further, since the drive electrode 134 and the piezoelectric thin film 131 are formed on each
electrode of the back surface 120a of the semiconductor element 120, the wiring between the
semiconductor element and each vibrator can be omitted. This eliminates the need for the wiring
board (630 in FIG. 6) on which the wiring between the vibrator and the changeover switch circuit
is formed, which is required in the above probe structure. Therefore, the configuration of the
ultrasound probe can be simplified.
[0027]
Although only the switch circuit is built in the semiconductor device in this embodiment, other
circuits may be built in the semiconductor device together with the switch circuit. Further, in the
present embodiment, the connector for cable connection is provided on the circuit mounting
13-04-2019
7
substrate, but the cable may be directly connected to the circuit mounting substrate by soldering
or the like without using the connector.
[0028]
Next, with reference to FIG. 3, a method of manufacturing the ultrasonic probe according to the
present embodiment will be described. The above-described changeover switch circuit and the
like are built into the semiconductor element used here.
[0029]
Solder bumps 124 for connection with the electrode pads on the circuit mounting substrate 110
side are formed on the electrodes on the back surface 120 b (surface 120 b facing the circuit
mounting substrate 110) side of the semiconductor element 120. On the other hand, conductive
thin films (for example, aluminum, copper, ITO, etc.) are formed on the electrodes arranged in a
matrix on the back surface 120 a of the semiconductor element 120 as thin film technology such
as sputtering. ) Is formed (FIG. 3 (a)).
[0030]
Then, a mask pattern is formed on a predetermined area (area where the insulating layer 133 is
to be formed) in the back surface 120 of the semiconductor element 120 by photo etching
technology (FIG. 3B).
[0031]
Thereafter, a piezoelectric thin film 131 of a piezoelectric material (piezoelectric ceramic such as
PZT, ZnO etc.) is formed on each drive electrode 133 in a vacuum atmosphere, an appropriate
controlled atmosphere or the like (FIG. 3 (c)) .
Examples of methods for forming these piezoelectric thin films 131 include electron beam
evaporation, activated reactive evaporation (ARE), sputtering, cluster ion beam (ICB), ion beam
sputtering (IBS), and chemical vapor deposition. A phase crystal growth (CVD) method, an atomic
layer epitaxial (ALE) growth method, a molecular beam epitaxial (MBE) growth method, a gas
13-04-2019
8
source (MBE or CBE) method, electron cyclotron resonance (ECR) or the like can be used.
[0032]
Thereafter, the piezoelectric thin film grown on the insulating layer 133 is removed, and then the
mask pattern 300 is removed. Then, an insulating resin or the like having a low viscosity is
poured into the region from which the mask pattern 300 is removed, and the insulating resin is
cured to form the insulating layer 133. However, when the mask pattern 300 is formed of an
insulating material such as a photoresist, the mask pattern 300 may be used as the insulating
layer 133 as it is.
[0033]
Then, a ground electrode 134 is formed to cover all the piezoelectric thin films 131 (FIG. 3 (d)).
The ground electrode 134 may be, for example, a conductive thin film grown by thin film
technology such as sputtering, a conductive resin layer formed by coating a conductive resin, or
a metal layer formed by adhesion of metal foil. Just do it.
[0034]
Thereafter, an acoustic matching layer 135 is formed on the ground electrode 134 by bonding a
material (for example, a mixture of metal powder and an epoxy resin) to the ground electrode
134 in order to match the acoustic impedance with the subject. Form (FIG. 3 (e)). When the
acoustic matching layer 135 is formed by adhering a material to match the acoustic impedance
with the subject, if a conductive adhesive is used to adhere the material, ground the conductive
adhesive layer. It may be used as an electrode.
[0035]
Thus, when the electroacoustic conversion layer 130 on the back surface 120 a side of the
semiconductor element 120 is completed, the semiconductor element 120 and other circuits and
the like are mounted on the circuit mounting substrate 110. Thereby, the ultrasound probe 100
is completed.
13-04-2019
9
[0036]
In the present embodiment, one ultrasonic probe 100 is manufactured. However, in the case of
manufacturing a plurality of ultrasonic probes, a wafer on which a plurality of semiconductor
elements are formed. The electroacoustic conversion layer 130 may be formed in one step on a
plurality of semiconductor elements formed on the wafer.
[0037]
Lastly, referring to FIG. 4, an ultrasonic image display apparatus which is an example of use of
the ultrasonic probe 100 according to the present embodiment will be described.
[0038]
The ultrasonic image display apparatus 400 comprises a monitor 401, a signal processing
system 402 to which a cable 111a from the ultrasonic probe 100 is connected, and the like.
[0039]
The signal processing system 402 generates a voltage (not shown) for generating a voltage for
driving each transducer of the ultrasonic probe 100, and monitors the output from the ultrasonic
probe 100. It has a conversion processing unit that converts it into luminance information, a
switch circuit of the ultrasound probe 100, and a control unit that controls the entire ultrasound
image display apparatus.
[0040]
With such a configuration, when the focal depth of the ultrasonic beam from the ultrasonic probe
100 is moved in the XY two-axis direction, a three-dimensional ultrasonic image of the object to
be observed is displayed on the monitor 401.
[0041]
Although the case where the present invention is applied to a 2D array probe has been described
above as an example, in the present invention, a probe other than a 2D array probe, for example,
a 1D array probe Etc. are also applicable.
[0042]
According to the present invention, it is possible to obtain a probe structure suitable for high-
13-04-2019
10
density mounting of fine transducers.
[0043]
Brief description of the drawings
[0044]
Fig.1 (a) is a front view of the ultrasound probe which concerns on one Embodiment of this
invention, (b) is the AA sectional view.
[0045]
2 is a wiring diagram of the changeover switch circuit portion of the semiconductor element
according to an embodiment of the present invention.
[0046]
3 is a diagram illustrating a method of manufacturing an ultrasonic probe according to an
embodiment of the present invention.
[0047]
4 is a schematic configuration diagram of an ultrasonic image display apparatus according to an
embodiment of the present invention.
[0048]
5 is a schematic configuration diagram of a conventional ultrasonic image display apparatus.
[0049]
6 is a diagram for explaining the structure of a conventional ultrasound probe.
[0050]
Explanation of sign
[0051]
DESCRIPTION OF SYMBOLS 100 ... Ultrasonic probe 110 ... Circuit mounting board 111 ...
13-04-2019
11
Connector 111a ... Cable 120 ... Semiconductor element 121 ... Switch circuit 130 ...
Electroacoustic conversion layer 131 ... Piezoelectric thin film 132 ... Drive electrode 133 ...
Insulating layer 134 ... Grand electrode 135 ... Acoustic matching layer 400 ... Ultrasonic image
display main body
13-04-2019
12
Документ
Категория
Без категории
Просмотров
0
Размер файла
21 Кб
Теги
description, jp2002027594
1/--страниц
Пожаловаться на содержимое документа