CN117928766A - Surface acoustic wave temperature sensor - Google Patents

Abstract

The present invention provides a surface acoustic wave temperature sensor, comprising a substrate layer, an interdigital transducer and a reflective grating, wherein: the interdigital transducer is arranged on the substrate layer; the reflective grating is arranged on the base layer and on both sides of the interdigital transducer. The quartz substrate layer is formed by cutting quartz crystal at a specific angle, which can improve the Q value of the device. The present invention solves the problems of low Q value and large insertion loss in the existing surface acoustic wave temperature sensor by cutting quartz crystal at a set angle. And the present invention has good accuracy through electrical signal output.

Description

A surface acoustic wave temperature sensor

The present invention claims priority to Chinese patent application No. 202311059957.9, filed on August 22, 2023, and entitled “A Surface Acoustic Wave Temperature Sensor”, the entire text of which is hereby incorporated by reference.

Technical Field

The present invention relates to the technical field of semiconductor plane manufacturing, and in particular to a surface acoustic wave temperature sensor.

Background technique

The cutting method of quartz crystal has a great influence on the performance and sensitivity of the sensor. Different crystal faces and cutting angles of quartz crystal produce different mechanical and electrical properties. Traditional surface acoustic wave temperature sensors based on quartz substrates often use XT and AT cut quartz substrates, which have low Q values and large insertion losses.

Summary of the invention

In view of the defects in the prior art, an object of the present invention is to provide a surface acoustic wave temperature sensor.

A surface acoustic wave temperature sensor provided according to the present invention comprises a substrate layer, an interdigital transducer and a reflective grating, wherein:

The interdigital transducer is arranged on the substrate layer;

The reflective grating strips are arranged on the substrate layer and on both sides of the interdigital transducer.

In one embodiment, the substrate layer is a quartz substrate.

In one embodiment, the φ angle of the quartz substrate ranges from -14° to -24°; the θ angle of the quartz substrate ranges from -25° to -45°; and the ψ angle of the quartz substrate ranges from +8° to +28°.

In one embodiment, the material of the IDT is aluminum, copper or platinum.

In one embodiment, it further comprises a helical antenna, wherein a signal output end of the helical antenna is connected to a signal output end of the interdigital transducer.

In one embodiment, the IDTs are disposed on the substrate layer in an overlapping manner.

In one embodiment, the interdigital transducer is disposed in the middle of the substrate layer.

In one embodiment, the reflective gratings are arranged at equal intervals on the left and right sides of the substrate layer.

In one embodiment, the length direction of the IDT is consistent with the length direction of the substrate layer.

In one embodiment, the reflective gratings are arranged on the left and right sides of the IDT, and a plurality of reflective gratings are arranged in parallel on each side.

Compared with the prior art, the present invention has the following beneficial effects:

The invention solves the problems of low Q value and large insertion loss of the existing surface acoustic wave temperature sensor by cutting a quartz crystal at a set angle.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

FIG1 is a schematic structural diagram of a surface acoustic wave temperature sensor based on a specially cut quartz substrate provided by a specific embodiment of the present invention;

FIG2 is a temperature-frequency linear relationship diagram of a surface acoustic wave temperature sensor based on a special cut quartz substrate of the present invention;

FIG. 3 is a schematic diagram of the structure of the helical antenna of the present invention.

The figure shows:

Interdigital transducer 1;

Reflective grating 2;

Base 3.

Detailed ways

The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

In an exemplary embodiment, as shown in FIG. 1 , the surface acoustic wave temperature sensor provided by the present invention may include: an interdigital transducer 1 , a reflective grating 2 , and a substrate layer 3 .

Among them, the interdigital transducer is arranged on the substrate layer; the reflective grating is arranged on the substrate layer and on both sides of the interdigital transducer. The interdigital transducer is a metal pattern shaped like the crossed fingers of two hands formed on the surface of the piezoelectric substrate, and its function is to realize the energy conversion between sound and electricity. The reflective grating is a series of parallel equal-width and equidistant lines engraved on the substrate layer. The substrate layer is the substrate of the surface wave temperature sensor.

Optionally, the interdigital transducer can be used to acquire the acquired surface acoustic wave and convert it into an electrical signal. The reflective grating is arranged on the substrate layer and on both sides of the interdigital transducer.

The surface acoustic wave temperature sensor can improve the Q value of the surface acoustic wave temperature sensor and reduce the insertion loss by arranging an interdigital transducer on the substrate layer and arranging reflective gratings on both sides of the interdigital transducer.

On the basis of the above embodiments, in an exemplary embodiment, a surface acoustic wave temperature sensor based on a specially cut quartz substrate is provided, including an interdigital transducer 1, reflective gratings 2 and a substrate 3, wherein the interdigital transducer 1 is arranged on the substrate 3 in an overlapping form, a specific number of reflective gratings 2 are arranged on both sides of the interdigital transducer 1, and the substrate layer adopts a quartz substrate.

Optionally, since the crystal planes and cutting angles of quartz crystals are different, the mechanical and electrical properties produced are also different, so the quartz substrate is used in this specific embodiment.

Furthermore, the φ angle of the quartz substrate can range from -14° to -24°, the θ angle of the quartz substrate can range from -25° to -45°, and the ψ angle of the quartz substrate can range from +8° to +28°. As shown in FIG2 , the surface acoustic wave temperature sensor composed of such a cut quartz substrate has a higher Q value and lower insertion loss, and its temperature and frequency meet the required linear relationship.

It can be understood that by setting a substrate layer using a quartz substrate and setting the ranges of the φ angle, θ angle and ψ angle of the quartz substrate, it is possible to improve the Q value of the surface acoustic wave temperature sensor and reduce the insertion loss, thereby making the temperature and frequency of the surface acoustic wave sensor meet the required linear relationship.

In an exemplary embodiment, the surface wave temperature sensor may include a helical antenna.

Wherein, the signal output end of the helical antenna is connected to the signal output end of the interdigital transducer.

Optionally, the quartz crystal can be cut into wafers according to the required cut shape, and the surface acoustic wave single-ended resonator can be made using micro-nano processing technology. The above-mentioned interdigital transducer 1 shares the signal input end and the signal output end, and the structure diagram of the helical antenna can be shown in Figure 3; and the signal output end of the helical antenna is connected to the signal output end of the interdigital transducer.

It can be understood that by setting up a helical antenna and connecting the signal output end of the helical antenna to the signal output end of the interdigital transducer, it is possible to match the peripheral circuit after measuring the direct signal and the acoustic signal, thereby achieving the effect of maximum power signal transmission.

In an exemplary embodiment, in the actual production process, the line accuracy of the interdigital transducers and reflective gratings required by all designs of the sensor can be ensured by using a negative resist stripping process in a micro-nano processing lithography process.

In an exemplary embodiment, the material of the IDT 1 may be aluminum, copper or platinum.

It should be noted that by setting the material of the IDT to aluminum, copper or platinum, the efficiency and accuracy of the IDT energy exchange between the acoustic signal and the electrical signal can be improved.

In an exemplary embodiment, the IDT is disposed in the middle of the base layer, and the length direction of the IDT is consistent with the length direction of the base layer.

Optionally, as shown in FIG. 1 , both the IDT and the substrate layer may be rectangular in shape, with the longer side being the length; further, the length direction of the IDT is consistent with the length direction of the substrate layer.

Furthermore, the reflective gratings are arranged on the left and right sides of the IDT, and a plurality of reflective gratings are arranged in parallel on each side.

Optionally, as shown in FIG. 1 , the reflective gratings may be disposed on the left and right sides of the IDT, and each side may include a plurality of reflective gratings, and the reflective gratings on each side are parallel to each other.

It can be understood that by setting the length direction of the IDT to be consistent with the length direction of the substrate layer and the reflection bars on the left and right sides of the IDT to be parallel to each other, the Q value of the surface acoustic wave temperature sensor can be improved and the insertion loss can be reduced.

In an exemplary embodiment, in a surface acoustic wave temperature sensor, the interdigital transducer on the substrate layer can realize the excitation and detection of the sound wave. When the temperature changes, the frequency of the sound wave excited by the interdigital transducer changes, which in turn causes the frequency of the electrical signal converted by the piezoelectric effect to change accordingly. For example, if the temperature changes by 1°C, the center frequency of the device shifts by 5kHz.

It can be understood that based on the surface acoustic wave temperature sensor, when the temperature changes, the frequency-changed sound wave is converted into an electrical signal whose frequency changes accordingly. By polishing the frequency change of the electrical signal, the temperature change can be mapped to the change in the center frequency of the device, and then output through the electrical signal with better accuracy.

In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other at will.

Claims (10)

1. A surface acoustic wave temperature sensor, comprising a substrate layer, an interdigital transducer and a reflective grating, wherein: The interdigital transducer is arranged on the base layer; The reflective grating strips are arranged on the base layer and on both sides of the interdigital transducer. 2 . The surface acoustic wave temperature sensor according to claim 1 , wherein the substrate layer is a quartz substrate. 3. The surface acoustic wave temperature sensor according to claim 2 is characterized in that the φ angle of the quartz substrate ranges from -14° to -24°; the θ angle of the quartz substrate ranges from -25° to -45°; and the ψ angle of the quartz substrate ranges from +8° to +28°. 4 . The surface acoustic wave temperature sensor according to claim 1 , wherein the material of the interdigital transducer is aluminum, copper or platinum. 5 . The surface acoustic wave temperature sensor according to claim 1 , further comprising a helical antenna, wherein a signal output end of the helical antenna is connected to a signal output end of the interdigital transducer. 6 . The surface acoustic wave temperature sensor according to claim 1 , wherein the interdigital transducers are arranged on the substrate layer in an overlapping manner. 7 . The surface acoustic wave temperature sensor according to claim 1 , wherein the interdigital transducer is disposed in the middle of the substrate layer. 8 . The surface acoustic wave temperature sensor according to claim 7 , wherein the reflective gratings are arranged at equal intervals on the left and right sides of the base layer. 9 . The surface acoustic wave temperature sensor according to claim 1 , wherein a length direction of the interdigital transducer is consistent with a length direction of the substrate layer. 10 . The surface acoustic wave temperature sensor according to claim 1 , wherein the reflection gratings are arranged on the left and right sides of the interdigital transducer, and a plurality of reflection gratings are arranged in parallel on each side.