Ultrasound probe and ultrasound equipment using same
View Patent ↗Provided are: an ultrasound probe with excellent characteristic stability; and ultrasound equipment that uses the ultrasound probe. The ultrasound probe has an ultrasonic transmitting and receiving element provided with a substrate, an insulating film formed on the substrate, a cavity formed between the substrate and the insulating film, and a pair of electrodes disposed parallel to the substrate so as to sandwich the cavity. The ultrasound probe is characterized in that the ultrasonic transmitting and receiving element has a beam part with a multilayer structure formed by laminating films made of materials different in stress, the beam part being disposed on the electrode distant from the substrate out of the pair of electrodes, and the beam part is formed by laminating a film that applies tensile stress and a film that applies compressive stress.
1. An ultrasound probe comprising:
an ultrasonic transmitting and receiving element including a substrate, an insulating film formed on the substrate, a cavity formed between the substrate and the insulating film, and a pair of electrodes disposed parallel to the substrate so as to sandwich the cavity,
wherein the ultrasonic transmitting and receiving element includes a multilayer structure formed by laminating insulating films, including a beam part, rim parts, and recess parts formed between the beam part and the rim parts, the beam part being disposed on the one electrode more distant from the substrate than the other electrode of the pair of electrodes and disposed above the cavity,
wherein the insulating films of the beam part are made of materials different in stress and include a film that applies tensile stress and a film that applies compressive stress,
wherein a number of layers of the insulating films included in the beam part is greater than a number of layers of insulating films included in the recess parts between the beam part and the rim parts, and
wherein a width of the beam part in a direction between the recess parts is less than a width of the cavity.
2. The ultrasound probe according to claim 1 , wherein
a stress neutral surface of the insulating film formed on the substrate in a direction perpendicular to the substrate is located at a position closer to the substrate than a beam neutral surface of the beam part in the direction perpendicular to the substrate.
3. The ultrasound probe according to claim 1 , wherein
a film that applies tensile stress is formed on an outer surface of the ultrasonic transmitting and receiving element, and
the beam part is formed by laminating a film that applies tensile stress, a film that applies compressive stress, a film that applies tensile stress and a film that applies compressive stress in this order from the side closest to the substrate.
4. The ultrasound probe according to claim 1 , wherein
the film that applies tensile stress is made of silicon nitride, and
the film that applies compressive stress is made of silicon dioxide.
5. The ultrasound probe according to claim 1 , wherein
a film that applies tensile stress is formed on an outer surface of the ultrasonic transmitting and receiving element, and
a film made of one or more selected from the group consisting of tungsten, tungsten carbide, tungsten boride, titanium nitride, titanium carbide, molybdenum, molybdenum boride, molybdenum carbide, titanium boride and silicon carbide is formed as an uppermost film in the beam part to be in contact with the film that applies tensile stress on the outer surface.
6. The ultrasound probe according to claim 1 , wherein
a sum of stresses of the films formed on the substrate is tensile stress.
7. The ultrasound probe according to claim 1 , wherein
the rim parts have a multilayer structure formed by laminating films made of materials different in stress, and
the rim parts overhang respective sides of the cavity at the edges of the cavity.
8. Ultrasound equipment comprising the ultrasound probe according to claim 1 .
9. An ultrasound probe comprising:
an ultrasonic transmitting and receiving element including a substrate, an insulating film formed on the substrate, a cavity formed between the substrate and the insulating film, and a pair of electrodes disposed parallel to the substrate so as to sandwich the cavity,
wherein the ultrasonic transmitting and receiving element includes a beam part with a multilayer structure as a first portion, recess parts as second portions, and rim parts as third portions, the second portions being disposed between the first portion and the third portions, each of the portions being formed by laminating films,
wherein the first portion and the third portions have an equal first number of layers of insulating films, and the first number of layers of the insulating films in the first portion and the third portions is greater than a second number of layers of insulating films of the second portions,
wherein the first portion is formed by laminating a film that applies tensile stress as one of the insulating films and a film that applies compressive stress as another of the insulating films, and
wherein the first portion is disposed on the one electrode more distant from the substrate than the other electrode of the pair of electrodes and disposed above the cavity, and the third portions being disposed above respective edges of the cavity,
wherein a width of the first portion in less than a width of the cavity.
10. The ultrasound probe according to claim 9 ,
wherein the third portions partially overlap respective ends of the one electrode more distant from the substrate than the other electrode of the pair of electrodes.