JPH0520499U - Ultrasonic probe - Google Patents

Abstract

(57) [Summary] [Purpose] It is to realize a small-sized probe that can be manufactured by a simple manufacturing process by integrally molding. [Structure] A logic circuit portion 22 composed of a vertical MOS FET 13 as a drive switch circuit and logic circuits 14 and 15 is formed on a Si wafer 12 by using a semiconductor process. The wafer back surface portion 18 provided on one surface has an output stage outlet port as one electrode 25.
It is composed of a thin film piezoelectric material 26 sandwiched between.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to an ultrasonic probe, and more particularly to an ultrasonic probe which has a drive circuit built therein and is manufactured by a simple manufacturing process and has been downsized.

[0002]

[Prior Art]

 An ultrasonic probe (hereinafter referred to as a probe) is a device that converts an input electric signal into an ultrasonic signal, receives the ultrasonic wave, and converts the electric signal into an electric signal.

A structure of a conventional probe is shown in FIG. In the figure, (a) is a structural view of the probe 1, and (b) is an enlarged view of a portion of the piezoelectric material 2. The piezoelectric material 2 is made of PZT or the like. A groove 3 is formed in the piezoelectric material 2 by machining as shown in FIG. 2B, and an individual electrode 4 is provided on the groove. In addition, a common electrode is provided on the back surface although not shown in the drawing. Reference numeral 5 is a signal line connected to each individual electrode 4. In the figure, the three piezoelectric materials 2 are connected as a group, and the signal line 5 is connected to each individual electrode 4 one by one. Has been. Reference numeral 6 denotes a plurality of acoustic matching layers provided on the upper surface of the piezoelectric material 2 in order to prevent reflection due to mismatch of acoustic impedance between the piezoelectric material 2 and a living body as an irradiation target. It is a backing material that acoustically damps and shortens the ultrasonic pulse waveform. An acoustic lens 8 is arranged on the upper surface of the acoustic matching layer 6 so as to converge the ultrasonic waves and improve the resolution.

[0004]

[Problems to be solved by the device]

 By the way, in the probe 1 having the above structure, fine processing of the piezoelectric material 2, extraction of a signal to a drive circuit (not shown), and assembly of the acoustic matching layer 6 are complicated, and further, Accurate positioning technology is also required, and miniaturization of the probe including the drive circuit is difficult.

The present invention has been made in view of the above points, and an object thereof is to realize a small-sized probe that can be manufactured by a simple manufacturing process by integrally molding.

[0006]

[Means for Solving the Problems]

 The present invention, which solves the above-mentioned problems, comprises a Si wafer, a vertical MOS FET which is a drive switch circuit formed on the Si wafer by using a semiconductor process, a first logic circuit and a second logic circuit. A logic circuit part, a back surface of the wafer formed on one surface of the Si wafer, a sink layer provided on the back surface of the wafer as an outlet for one pole of the vertical MOS FET, and It is provided with a thin film piezoelectric material as an ultrasonic vibrator provided under the back surface of the wafer via an insulating layer, and a first electrode and a second electrode sandwiching the thin film piezoelectric material. And

[0007]

[Action]

 A drive switch circuit section consisting of a vertical MOS FET and two logic circuits is formed on a Si wafer by using a semiconductor process, and an output stage outlet is provided on one surface of the wafer to connect to an electrode. The thin film piezoelectric material is sandwiched between this electrode and the counter electrode to form a probe, and the drive switch circuit section is operated by an input signal to operate the probe composed of the thin film piezoelectric material sandwiched by the counter electrode. select.

[0008]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a high withstand voltage IC 11 using a semiconductor process of a probe according to an embodiment of the present invention. In the figure, 12 is a wafer made of Si, 13 is a vertical MOS FET formed on the Si wafer 12, S is a source, and G is a gate. Further, 14 is a logic circuit A made of nMOS, and 15 is a logic circuit B made of pMOS. The vertical MOS FET 13, the logic circuit A14, and the logic circuit B15 are electrically separated by an element separation unit 16 formed of a p layer.

The drain D of the vertical MOS FET 13 is taken out through the sink layer 17 to the wafer back surface portion 18 below the Si wafer 12. FIG. 2 is a cross-sectional view of the probe 21 made of the high voltage IC 11 shown in FIG. In the figure, the same parts as those in FIG. 1 are designated by the same reference numerals. In the figure, 22 is a logic circuit section composed of the logic circuit A14 and the logic circuit B15 shown in FIG. 1, and 23 is a high breakdown voltage switch array composed of a plurality of vertical MOS FETs 13.

An insulating layer 24 made of SiO ₂ or the like is formed on the back surface 18 of the wafer, and an electrode A 25 is formed on the other surface of the insulating layer 24. The electrode A 25 has a drain of the vertical MOS FET 13. Are pierced through the insulating layer 24 and connected. Reference numeral 26 is a thin film piezoelectric material formed by depositing a thin film on the insulating layer 24 by sputtering ZnO, AlN (aluminum nitride) or the like.

Reference numeral 27 is an electrode B formed on the lower surface of the thin film piezoelectric material 26. FIG. 3 is an equivalent circuit of the probe 11 of FIG. In this circuit, an input signal is calculated by the logic circuit section 22, the high breakdown voltage switch array 23 selects a switching position based on the calculation result, and a voltage is selectively applied between the electrode A25 and the electrode B27. Ultrasonic waves are generated by the piezoelectric effect of the thin film piezoelectric material 26.

FIG. 4 is a structural diagram of a two-dimensional array probe 30 using the probe 21 of FIG. In the figure, the same reference numerals are used for the same parts as in FIG. The two-dimensional array probe 30 has electrodes A25 and electrodes B27 facing each other arranged in an array, and a high breakdown voltage switch array 23 is provided on each electrode A25 via a wafer rear surface portion 18 as shown in FIG. It is a structure that is arranged.

The logic circuit section 22 is provided at the position shown in the figure. The input signal is calculated by the logic circuit A14 and the logic circuit B15 shown in FIG. 2, and the switching position of the high voltage switch array 23 is calculated based on the calculation result. By selectively applying a voltage between the electrode A25 and the electrode B27, and generating an ultrasonic wave according to the spatial distribution of the selected high withstand voltage switch array 23 by the piezoelectric effect of the thin film piezoelectric material 26. , Change the directivity of ultrasonic waves.

The shape of this electrode arrangement is not limited to the square shown in FIG. 4, but may be a hexagon or the like, and the arrangement method may be other than the serial arrangement, and the same manufacturing method can be used. .

As described above, according to the present embodiment, the accuracy of alignment is improved by integrally forming the logical circuit as the drive circuit, the high voltage switch array, the piezoelectric material, and the counter electrode in the semiconductor process. , High precision and small size probe can be manufactured. Further, the assembly process as in the past is eliminated, the manufacturing cost can be reduced, and the reliability is high. Further, by arranging the counter electrodes in an array as shown in FIG. 4, improvement in acoustic characteristics can be expected.

[0016]

[Effect of the device]

 As described above in detail, according to the present invention, by integrally molding the probe, it is possible to realize a small probe with a simple manufacturing process, and the practical effect is great.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the configuration of one element of a probe according to an embodiment of the present invention.

FIG. 2 is a sectional view of a probe according to an embodiment of the present invention.

FIG. 3 is a diagram of an equivalent circuit of the probe of the example.

FIG. 4 is a structural diagram of a two-dimensional array probe including the probe of the example.

FIG. 5 is a structural diagram of a conventional probe.

[Explanation of symbols]

 11 High Voltage IC 12 Si Wafer 13 Vertical MOS FETs 14, 15 Logic Circuit 16 Element Separation Part 17 Sink Layer 18 Wafer Backside Part 21 Probe 22 Logic Circuit Part 23 High Voltage Switch Array 24 Insulating Layer 25 Electrode A 26 Thin Film Piezoelectric Material 27 Electrode B

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 29/784

Claims (1)

[Scope of utility model registration request] 1. A Si wafer (12) and a vertical MOS FET (1) which is a drive switch circuit formed on the Si wafer (12) by using a semiconductor process.
3) and the first logic circuit (14) and the second logic circuit (1
5), a logic circuit portion (22), a wafer back surface portion (18) formed on one surface of the Si wafer (12), and the vertical MOS on the wafer back surface portion (18). FET
A sink layer (17) provided as an outlet for one pole of (13), and a thin film piezoelectric material as an ultrasonic transducer provided under the wafer back surface portion (18) via an insulating layer (24). (26)
And a first electrode (25) and a second electrode (27) sandwiching the thin film piezoelectric material (26), an integrated ultrasonic probe.