阅读说明：本技术 一种声表面波温度传感器、耐高温封装结构及封装方法 (Surface acoustic wave temperature sensor, high-temperature-resistant packaging structure and packaging method ) 是由 吉小军 马晓鑫 高孜航 于 2021-08-18 设计创作，主要内容包括：本发明提供一种声表面波温度传感器、耐高温封装结构及封装方法,包括耐高温的陶瓷封装结构盖、过渡材料层、绝缘隔离层、陶瓷封装结构底座。耐高温的陶瓷封装结构盖具有一定高度,并通过高温胶粘接在陶瓷封装结构底座上。绝缘隔离层与过渡材料层生长在陶瓷封装结构底座的上表面。嵌入式电极层采用双层结构,上层电极与下层电极通过工艺方法内嵌于传感器基底的上表面。金属化平面天线采用一体化设计并生长在绝缘隔离层上表面。本发明提出的封装结构设计可实现在700℃高温环境下声表面波温度传感器的正常工作。(The invention provides a surface acoustic wave temperature sensor, a high-temperature-resistant packaging structure and a packaging method. The high-temperature-resistant ceramic packaging structure cover has a certain height and is bonded on the ceramic packaging structure base through high-temperature glue. The insulating isolation layer and the transition material layer are grown on the upper surface of the ceramic packaging structure base. The embedded electrode layer adopts a double-layer structure, and the upper electrode and the lower electrode are embedded on the upper surface of the sensor substrate through a process method. The metallized planar antenna adopts an integrated design and grows on the upper surface of the insulating isolation layer. The packaging structure design provided by the invention can realize the normal work of the surface acoustic wave temperature sensor in a high-temperature environment of 700 ℃.)

1. The utility model provides a surface acoustic wave temperature sensor's high temperature resistant packaging structure which characterized in that includes: the high-temperature-resistant ceramic packaging structure comprises a high-temperature-resistant ceramic packaging structure cover, a transition material layer, an insulating isolation layer and a ceramic packaging structure base; wherein:

the high-temperature-resistant ceramic packaging structure cover has a certain height and is bonded on the ceramic packaging structure base through high-temperature glue, and a sealing cavity for accommodating the surface acoustic wave temperature sensor structure is formed between the high-temperature-resistant ceramic packaging structure cover and the ceramic packaging structure base;

the insulating isolation layer and the transition material layer grow on the upper surface of the ceramic packaging structure base and are located in the sealing cavity.

2. The high temperature resistant package structure of surface acoustic wave temperature sensor as claimed in claim 1, wherein a metallized planar antenna is grown on the upper surface of the insulating isolation layer to improve the transmission efficiency of the metallized planar antenna.

3. The high temperature resistant package structure of a surface acoustic wave temperature sensor as claimed in claim 1, wherein a sensor substrate and a sensing unit on the sensor substrate are disposed on the transition material layer, so that the sensor substrate and the ceramic package structure base are connected together and a higher acoustic velocity can be obtained.

4. The high temperature resistant package structure of a surface acoustic wave temperature sensor as claimed in claim 1, wherein there are two insulating isolation layers symmetrically disposed near two ends of the closed cavity, respectively, and said transition material layer is disposed between the two insulating isolation layers.

5. A surface acoustic wave temperature sensor comprising the high temperature resistant package structure of any one of claims 1-4.

6. A surface acoustic wave temperature sensor according to claim 5, further comprising: the embedded electrode layer is of a double-layer structure formed by an upper electrode and a lower electrode, and the upper electrode and the lower electrode are embedded in the upper surface of the sensor substrate.

7. A surface acoustic wave temperature sensor according to claim 6, further comprising an aluminum nitride protective layer on the embedded electrode layer, protecting the embedded electrode layer together with the sensor substrate.

8. A surface acoustic wave temperature sensor according to claim 5, wherein said embedded electrode layer is connected to a metallized planar antenna layer through a connection line, said metallized planar antenna layer being integrally designed and grown on the upper surface of the insulating spacer layer.

9. A method for packaging a surface acoustic wave temperature sensor according to any one of claims 5 to 8, comprising:

s1, growing a transition material layer on the upper surface of the ceramic packaging structure base;

s2, growing the sensitive unit of the surface acoustic wave temperature sensor on the transition material layer;

s3, growing the insulation isolation layer on the upper surface of the ceramic packaging structure base;

s4, bonding a metallized planar antenna on the insulating isolation layer;

s5, connecting the sensitive unit of the surface acoustic wave temperature sensor with the metallized plane antenna by using a high-temperature resistant connecting wire;

and S6, bonding the high-temperature-resistant ceramic packaging structure cover to the ceramic packaging structure base through high-temperature glue to form a sealing cavity, and completing packaging.

10. The packaging method for a surface acoustic wave temperature sensor as claimed in claim 9, further comprising, between said S2, S3: and depositing an aluminum nitride protective layer on the sensitive unit of the surface acoustic wave temperature sensor.

Technical Field

The invention relates to the technical field of sensor packaging, in particular to a surface acoustic wave temperature sensor, a high-temperature-resistant packaging structure and a packaging method.

Background

The high-temperature sensor has wide application requirements in the fields of aerospace, aviation, national defense construction, energy development and the like. For example, main parts of power equipment such as rocket engines and aero-engines in the aerospace field, heavy gas turbines and coal-fired gas boilers in the large-scale ship field are in a high-temperature severe environment, the temperature of a combustion chamber even exceeds 1500 ℃, parameters such as pressure and temperature of key parts such as a nozzle combustion chamber, an air compressor and blades can be monitored in real time by using a high-temperature sensor, the combustion performance and the propulsion efficiency are improved, and the health state of the parts is evaluated. Therefore, sensing measurement in a high-temperature environment becomes one of key technologies which must be broken through and mastered in the military industry fields of aerospace, ships and naval vessels and the like.

The surface acoustic wave sensor is a wireless passive sensor which uses a surface acoustic wave device as a sensitive element, can reflect measured physical quantity through the change of the speed or frequency of the surface acoustic wave and outputs radio frequency electric signals. The essence of the surface acoustic wave is that the surface acoustic wave is propagated along the surface of the substrate, and the energy of the surface acoustic wave is concentrated, so that the surface acoustic wave is quite sensitive to physical, chemical and other parameters of the surface disturbance of the piezoelectric structure, and various sensors with high sensitivity can be manufactured. Meanwhile, the surface acoustic wave sensor also has the advantages of small volume, high precision, high working temperature, long coupling distance and the like, and is a novel piezoelectric sensor with great development prospect.

The high-temperature surface acoustic wave sensor is an important research direction in the field of high-temperature sensing, and a plurality of scientific research institutes and colleges are engaged in related research works of the surface acoustic wave sensor in the field of high temperature. In the manufacturing and testing of high-temperature surface acoustic wave sensors, packaging technology plays a crucial role. Under the high temperature condition, the biggest problem of surface acoustic wave sensor encapsulation is that various requirements of the surface acoustic wave sensor for high-reliability work in a larger temperature range need to be met, the existing encapsulation method cannot effectively solve the temperature resistance characteristic of an encapsulation structure, and the thermal stress of the structure needs to be improved.

The invention discloses a surface acoustic wave high-temperature pressure sensing chip based on a silicon crystal cell and a piezoelectric film, and discloses a structure of a sensing chip of a silicon-based surface acoustic wave high-temperature pressure sensor, wherein the surface acoustic wave high-temperature pressure sensing chip is published under CN107631827A and published under 2017, 9, month and 11. The technical scheme focuses on the sensor structure design of the surface acoustic wave high-temperature sensor, and the application of a high-temperature packaging structure in the aspect of the surface acoustic wave high-temperature sensor is not deeply explored.

The invention discloses a multi-parameter surface acoustic wave sensing device and a preparation method thereof, and relates to an application under a high-temperature environment, wherein the application is CN110081918A and published as 2019, 4, month and 26. The structure comprises a high-temperature resistant piezoelectric crystal substrate, a first resonator, a second resonator, a third resonator, a response antenna and the like. The solution focuses on the concept of multi-parameter detection and does not take into account the sensing problems to be measured, including the problem of how reliably temperature, pressure, vibration are transmitted to the sensing device. At the same time, no specific work has been done on the structural package design under the mentioned high temperature environment.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a surface acoustic wave temperature sensor, a high-temperature-resistant packaging structure and a packaging method, which can effectively provide fixation, sealing and protection for the surface acoustic wave temperature sensor in a high-temperature environment and simultaneously ensure effective transmission of a measured signal and lossless input and output of an excitation signal and a measurement signal. And provides support for the design and application of the high-temperature surface acoustic wave sensor.

In a first aspect of the present invention, a high temperature resistant package structure of a surface acoustic wave temperature sensor is provided, which includes: the high-temperature-resistant ceramic packaging structure comprises a high-temperature-resistant ceramic packaging structure cover, a transition material layer, an insulating isolation layer and a ceramic packaging structure base; wherein:

the high-temperature-resistant ceramic packaging structure cover has a certain height and is bonded on the ceramic packaging structure base through high-temperature glue, and a sealing cavity for accommodating the surface acoustic wave temperature sensor structure is formed between the high-temperature-resistant ceramic packaging structure cover and the ceramic packaging structure base;

the insulating isolation layer and the transition material layer grow on the upper surface of the ceramic packaging structure base and are located in the sealing cavity.

Optionally, a metalized planar antenna is grown on the upper surface of the insulating isolation layer, so that the transmission efficiency of the metalized planar antenna is improved.

Optionally, a sensor substrate and a sensing unit located on the sensor substrate are arranged on the transition material layer, so that the sensor substrate is connected with the ceramic package structure base, and a higher sound velocity can be obtained.

Optionally, there are two insulating isolation layers, which are symmetrically disposed near two ends of the closed cavity, respectively, and the transition material layer is disposed between the two insulating isolation layers.

In a second aspect of the present invention, a surface acoustic wave temperature sensor is provided, which includes the above high temperature resistant package structure.

Further, the surface acoustic wave temperature sensor further includes: the sensor comprises a sensing unit, wherein the sensing unit is an embedded electrode layer, the embedded electrode layer adopts a double-layer structure formed by an upper electrode and a lower electrode, and the upper electrode and the lower electrode are embedded in the upper surface of a sensor substrate.

Further, the surface acoustic wave temperature sensor further includes: and the aluminum nitride protective layer is positioned on the embedded electrode layer and protects the embedded electrode layer together with the sensor substrate.

Optionally, the embedded electrode layer is connected to the metallized planar antenna layer through a connection line, and the metallized planar antenna layer is integrally designed and grown on the upper surface of the insulating isolation layer.

In a third aspect of the present invention, a method for packaging a surface acoustic wave temperature sensor is provided, including:

s1, growing a transition material layer on the upper surface of the ceramic packaging structure base;

s2, growing the sensitive unit of the surface acoustic wave temperature sensor on the transition material layer;

s3, growing the insulation isolation layer on the upper surface of the ceramic packaging structure base;

s4, bonding a metallized planar antenna on the insulating isolation layer;

s5, connecting the sensitive unit of the surface acoustic wave temperature sensor with the metallized plane antenna by using a high-temperature resistant connecting wire;

and S6, bonding the high-temperature-resistant ceramic packaging structure cover to the ceramic packaging structure base through high-temperature glue to form a sealing cavity, and completing packaging.

Optionally, between S2 and S3, further comprising: and depositing an aluminum nitride protective layer on the sensitive unit of the surface acoustic wave temperature sensor.

Compared with the prior art, the embodiment of the invention has at least one of the following beneficial effects:

the surface acoustic wave temperature sensor, the high-temperature-resistant packaging structure and the packaging method thereof provided by the invention save the packaging cost, improve the preparation efficiency, and have the characteristics of low cost, high reliability, multiple purposes and the like. And the packaging material does not generate electromagnetic interference on the sensor chip and plays a role in fixing and protecting the metallized planar antenna and the surface acoustic wave temperature sensor.

The surface acoustic wave temperature sensor, the high-temperature-resistant packaging structure and the packaging method thereof have the advantages that the packaging reliability is guaranteed, the overall structure of the packaging structure is compact, the size of the sensor is reduced as much as possible, the hysteresis, the creep and the nonlinear characteristics of the sensor are improved, and the detection precision is improved. The packaging structure design provided by the invention can realize the normal work of the surface acoustic wave temperature sensor in a high-temperature environment of 700 ℃.

Drawings

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

FIG. 1 is a front view of a high temperature SAW temperature sensor and package structure provided in an embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating a process of a protective layer in the packaging method according to an embodiment of the present invention;

FIGS. 3-8 are schematic diagrams illustrating steps of a packaging method according to an embodiment of the invention;

wherein, 1 is a high temperature resistant ceramic packaging structure cover; 2 is a sensor substrate; 3 is an insulating isolation layer; 4 is a metallized plane antenna layer; 5 is the upper electrode of the embedded electrode layer; 6 is a ceramic packaging structure base; 7 is a connecting line; 8 is the lower electrode of the embedded electrode layer; 9 is an aluminum nitride protective layer; 10 is a bonding pad; and 11 is a transition material layer.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

Referring to fig. 1, in an embodiment of the present invention, a high temperature resistant package structure of a surface acoustic wave temperature sensor is provided, where 1 is a high temperature resistant ceramic package structure cover; 2 is a sensor substrate; 3 is an insulating isolation layer; 4 is a metallized plane antenna layer; 11 is a transition material layer; 5 is the upper electrode of the embedded electrode layer; 8 is the lower electrode of the embedded electrode layer; 7 is a connecting line; 9 is an aluminum nitride protective layer; and 6, a ceramic packaging structure base.

Specifically, the high temperature resistant package structure of the surface acoustic wave temperature sensor of the present embodiment includes: high temperature resistance ceramic package structure lid 1, insulating isolation layer 3, transition material layer 11 and ceramic package structure base 6, wherein: the high-temperature-resistant ceramic packaging structure cover 1 has a certain height and is bonded on the ceramic packaging structure base 6 through high-temperature glue, and a sealing cavity for accommodating the surface acoustic wave temperature sensor is formed between the high-temperature-resistant ceramic packaging structure cover 1 and the ceramic packaging structure base 6; the insulating isolation layer 3 and the transition material layer 11 grow on the upper surface of the ceramic packaging structure base 6 and are located in the sealed cavity.

The metallized planar antenna 4 is grown on the upper surface of the insulating isolation layer 3, so that the transmission efficiency of the metallized planar antenna 4 can be improved. Specifically, the metallized planar antenna layer 4 is integrally designed and grown on the upper surface of the insulating isolation layer 3.

The sensor substrate 2 and the sensitive unit positioned on the sensor substrate 2 are arranged on the transition material layer 11, so that the sensor substrate 2 is connected with the ceramic packaging structure base 6, and a higher sound velocity can be obtained. Further, the sensing unit is an embedded electrode layer, such as an embedded Pt electrode layer, the embedded electrode layer adopts a double-layer structure, and the upper electrode 5 and the lower electrode 8 are embedded in the upper surface of the sensor substrate 2.

In this embodiment, there are two insulating isolation layers 3, which are symmetrically disposed near two ends of the closed cavity, respectively, and the transition material layer 11 is disposed between the two insulating isolation layers 3.

Referring to fig. 1, in another embodiment of the present invention, a surface acoustic wave temperature sensor is further provided, where the sensor includes the above-mentioned high temperature resistant package structure.

Specifically, the surface acoustic wave temperature sensor further includes: the sensing unit is an embedded electrode layer, the embedded electrode layer adopts a double-layer structure formed by an upper electrode and a lower electrode, and the upper electrode 5 and the lower electrode 8 are embedded in the upper surface of the sensor substrate 2.

Preferably, the surface acoustic wave temperature sensor further includes: and an aluminum nitride protective layer 9, wherein the aluminum nitride protective layer 9 is positioned on the embedded electrode layers (the upper electrode 5 and the lower electrode 8) and protects the embedded electrode layers together with the sensor substrate 2. The embedded electrode layer (the upper electrode 5 and the lower electrode 8) is connected with the metallized planar antenna layer 4 through a connecting wire 7, and the metallized planar antenna layer 4 adopts an integrated design and grows on the upper surface of the insulating isolation layer 3.

The embodiment of the invention can effectively provide fixation, sealing and protection for the surface acoustic wave sensor in a high-temperature environment, simultaneously ensure effective transmission of measured signals and lossless input and output of excitation signals and measurement signals, and provide support for the design and application of the high-temperature surface acoustic wave sensor. The packaging structure design can realize the normal work of the surface acoustic wave temperature sensor in a high-temperature environment of 700 ℃.

In order to more clearly illustrate the technical solutions in the preferred embodiments of the present invention, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

As shown in fig. 1, in a preferred embodiment, the high temperature resistant ceramic package structure cover 1 is bonded to the ceramic package structure base 6 by high temperature glue, so that a sealed cavity, which is a sealed environment, is formed inside the ceramic package structure cover, and the surface acoustic wave temperature sensor and the antenna can be protected to a certain extent. The insulating isolation layer 3 and the transition material layer 11 grow on the upper surface of the ceramic packaging structure base 6 and are located in the sealed cavity.

In the present embodiment, the transition material layer 11 may be, but is not limited to, an alumina material. The transition material layer 11 can be grown by using a chemical vapor deposition method in a high temperature environment. The introduction of the transition material layer 11 can effectively connect the sensor substrate 2 and the ceramic packaging structure base 6 together, so that the falling failure of a sensing device caused by cracking due to high temperature can be relieved to a certain extent, and the adhesiveness is improved. Meanwhile, the transition material layer 11 is introduced, so that a higher sound velocity can be obtained, and the quality factor of the surface acoustic wave temperature sensor is improved.

In the present embodiment, the insulating spacer layer 3 may be, but is not limited to, an LGS material. The insulating isolation layer 3 grows on the ceramic packaging structure base 6, and the upper surface of the insulating isolation layer is a metalized planar antenna layer 4. Set up insulating isolation layer 3 and can promote metallized planar antenna's transmission efficiency effectively between metallized planar antenna layer 4 and ceramic package structure base 6, meanwhile, because high temperature can cause the metallized planar antenna to oxidize, set up insulating isolation layer 3 and can play the guard action to metallized planar antenna to a certain extent, prevent that it from causing the obvious reduction of transmission performance because of the high temperature shrink.

In this embodiment, the ceramic package structure is composed of a high temperature resistant ceramic package structure cover 1 and a ceramic package structure base 6. The ceramic packaging structure adopts alumina industrial ceramic material. The alumina industrial ceramic is a good high-temperature resistant material and has good insulativity. The alumina industrial ceramic can maintain the strength thereof within 1500 ℃ without deformation, meets certain mechanical strength requirements, has good air tightness and stable chemical performance in a ceramic packaging structure, and is an ideal packaging material for the high-temperature surface acoustic wave sensor.

In this embodiment, the embedded electrode layer includes two portions, i.e., an embedded upper electrode 5 and an embedded lower electrode 6. The embedded upper and lower electrodes 6 are made of, but not limited to, Pt and Mo materials. In a high-temperature environment, the degradation phenomenon of the electrode can reduce the conversion efficiency between an electric field and a sound field of the surface acoustic wave temperature sensor, and the effective reflection of the surface acoustic wave is weakened, so that the quality factor of the surface acoustic wave temperature sensor is seriously reduced. Therefore, the embedded electrode can protect the electrode structure to a certain extent, and the influence of high temperature on the surface acoustic wave sensor is reduced. However, since metal is oxidized in a high temperature environment and the volume of the metal is reduced, the performance of the metal is reduced by using the embedded electrode. Therefore, the embedded electrode layer provided by the invention adopts an upper and lower double-layer structure, and can effectively improve the condition that the quality factor of the surface acoustic wave temperature sensor is seriously reduced due to the degradation phenomenon of the metal electrode in a high-temperature environment.

In this embodiment, the metallized planar antenna is made of Pt, but not limited thereto. The metal platinum (Pt) can still keep good conductivity after being calcined at the high temperature of 1500 ℃, and the metal quality is not changed. Therefore, the use of platinum (Pt) as an antenna material for high temperature saw temperature sensors is a desirable choice. Specifically, the growth of the metallized planar antenna structure with the required thickness is realized by using a method combining magnetron sputtering and electron beam evaporation. The design of the metallized planar antenna structure is subjected to simulation analysis through three-dimensional electromagnetic analysis software, and the matching of the antenna is evaluated and analyzed to obtain the resonance parameters of the metallized planar antenna. Under a high-temperature environment, the influence of temperature on the antenna performance of the surface acoustic wave temperature sensor mainly changes the dielectric constant. The frequency variation range of the surface acoustic wave temperature sensor is ensured to be within the antenna bandwidth range, and the technical route for designing the surface acoustic wave temperature sensor under the high-temperature condition is met.

As shown in fig. 2 to 8, there are provided steps of a method for packaging a surface acoustic wave temperature sensor according to a preferred embodiment of the present invention, wherein:

as shown in fig. 2, a transition material layer 11 is grown on the upper surface of the ceramic package structure base 6;

as shown in fig. 3, the saw temperature sensor sensitive unit is grown on the transition material layer 11;

as shown in fig. 4, an aluminum nitride protective layer 9 is deposited on the sensitive unit of the surface acoustic wave temperature sensor;

as shown in fig. 5, an insulating isolation layer 3 is grown on the upper surface of the ceramic package structure base 6;

as shown in fig. 6, a metallized planar antenna is bonded on the insulating isolation layer 3;

as shown in fig. 7, the sensitive unit of the surface acoustic wave temperature sensor is connected with the metallized planar antenna by a high temperature resistant connecting wire;

as shown in fig. 8, the high temperature resistant ceramic package structure cover 1 is bonded to the ceramic package structure base 6 by high temperature glue, and the package is completed.

According to the surface acoustic wave temperature sensor, the high-temperature-resistant packaging structure and the packaging method thereof, provided by the embodiment of the invention, the packaging reliability is ensured, the whole structure of the packaging structure is compact, the size of the sensor is reduced as much as possible, and the hysteresis, the creep and the nonlinear characteristics of the sensor are improved, so that the detection precision is improved.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The above-described preferred features may be used in any combination without conflict with each other.