Packaging structure and packaging process of an atomic layer thermopile thermal flow sensor

Abstract

The invention discloses a packaging structure and packaging process of an atomic layer thermopile heat flow sensor. The packaging structure comprises: a base; a packaging sleeve, which is tightly matched with the base; a sensitive element, which is fixed on the base and whose outer surface is flush with the upper end surface of the packaging sleeve; a lead hole I, which is located in the base and arranged at the upper end of the base; the structure of the sensitive element comprises: a strontium titanate wafer, on which a lead hole II is opened, and the lead hole II is located directly above the lead hole I; a thermoelectric effect film, which is deposited on the strontium titanate wafer; a conductive gold film, which is deposited on the strontium titanate wafer and located at both ends of the thermoelectric effect film; a wire groove, which is opened in the base; a silver wire, which is fixed in the wire groove, and the silver wire passes through the lead hole I and the lead hole II. The heat flow sensor packaging structure and packaging process provided by the invention avoid the difficulty of processing fine holes with a large aspect ratio and realize effective fixing of the wire.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat flux sensors, and more specifically, relates to a packaging structure and packaging process of an atomic layer thermopile heat flux sensor. Background Art

[0002] Boundary layer transition is one of the few fundamental scientific problems left over from classical mechanics, and along with turbulence, is considered a "century-old problem." In hypersonic flight, when the hypersonic boundary layer transitions from laminar to turbulent flow, both wall heat flux and friction increase dramatically. Therefore, theoretical and experimental research on hypersonic boundary layer transition is an important means of understanding the transition mechanism and, therefore, controlling it. Based on current theoretical research on hypersonic boundary layer transition, the evolution and development of incoming flow disturbances are considered to be the core of the boundary layer transition mechanism. Accordingly, wind tunnel testing is increasingly focusing on the testing and analysis of high-frequency pulsating heat flux. Currently, high-frequency pulsating heat flux testing, both domestically and internationally, primarily utilizes atomic layer thermopile heat flux sensors, and such sensors are still lacking in China. Based on the heat measurement principles of foreign atomic layer thermopile heat flux sensors (Tim Roediger et al. from the University of Stuttgart, Germany, published articles such as "Time-resolved heat transfer measurements on the tip wall of a bibbed channel using a novel heat flux sensor—Part I: Sensor and benchmarks"), a sensor packaging structure and process were designed to avoid the difficulty of machining small holes with large aspect ratios and achieve effective wire fixation. This resulted in an atomic layer thermopile heat flux sensor suitable for use in shock tunnels and conventional hypersonic wind tunnels. Summary of the Invention

[0003] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0004] In order to achieve these purposes and other advantages according to the present invention, a packaging structure of an atomic layer thermopile heat flow sensor is provided, comprising:

[0005] base;

[0006] The packaging sleeve is tightly fitted with the base; the sensitive element is fixed on the base, and its outer surface is flush with the upper end surface of the packaging sleeve; the lead hole I is provided in the base;

[0007] The structure of the sensitive element includes: a strontium titanate wafer with a lead hole II formed thereon, wherein the lead hole II coincides with the central axis of the lead hole I; a thermoelectric effect film deposited on the strontium titanate wafer; and a conductive gold film deposited on the strontium titanate wafer and covering the surface of the strontium titanate wafer around the lead hole II and located at both ends of the thermoelectric effect film.

[0008] A wire groove is provided in the base, and the lead hole I is located between the sensitive element and the wire groove; a silver wire is fixed in the wire groove, and the silver wire passes through the lead hole I and the lead hole II and forms electrical conduction with the conductive gold film.

[0009] Preferably, the packaging sleeve is one of insulating packaging sleeves such as a polyetheretherketone packaging sleeve, an aluminum nitride ceramic packaging sleeve, a silicon nitride ceramic packaging sleeve, and an alumina ceramic packaging sleeve; and the base is an aluminum alloy base with an anodized surface.

[0010] Preferably, the thermoelectric effect film is one of films having a lateral Seebeck effect, such as a yttrium barium copper oxide film and a lanthanum manganese copper oxide film.

[0011] Preferably, the number of the wire grooves and the number of the silver wires are respectively two, and the wire grooves are filled with glue, and the silver wires are fixed in the base by the glue.

[0012] Preferably, a conductive glue is applied between the silver wire and the conductive gold film to achieve electrical conduction between the silver wire and the conductive gold film.

[0013] Preferably, the end surface of the silver wire is flush with the outer surface of the sensitive element.

[0014] Preferably, the diameter of the strontium titanate wafer is less than or equal to 6 mm, and the thickness is less than or equal to 0.5 mm; the diameter of the lead hole I and the lead hole II is 0.2 mm.

[0015] A packaging structure of an atomic layer thermopile heat flow sensor, wherein the packaging process includes the following steps:

[0016] Step 1: Perform an anodic surface treatment on the aluminum alloy base; use mechanical processing or femtosecond laser processing to shape the strontium titanate wafer and open two lead holes II with a diameter of 0.2 mm at designated positions symmetrically in the center of the strontium titanate wafer; use an ion polishing process to treat the surface of the strontium titanate wafer; and deposit a yttrium barium copper oxide thin film and a conductive gold film on the strontium titanate wafer by physical vapor deposition to form the sensitive element of the atomic layer thermopile heat flow sensor;

[0017] Step 2: Fix the sensitive element on the aluminum alloy base by gluing, and ensure that the lead hole II is aligned with the lead hole I in the aluminum alloy base;

[0018] Step 3: Pass the silver wire through lead hole I and lead hole II, pour glue into the wire groove, and fix the silver wire in the aluminum alloy base. Make sure the silver wire is completely immersed in the wire groove, and the end surface of the silver wire is flush with the outer surface of the sensitive element;

[0019] Step 4: Apply conductive silver glue between the silver wire and the conductive gold film to achieve electrical conduction between the silver wire and the conductive gold film;

[0020] Step 5. Place the polyetheretherketone encapsulation sleeve on the aluminum alloy base, and ensure that the polyetheretherketone encapsulation sleeve and the aluminum alloy base are tightly fitted, and the upper end surface of the polyetheretherketone encapsulation sleeve is flush with the outer surface of the sensitive element; the polyetheretherketone encapsulation sleeve is used to further protect the sensitive element and to electrically insulate the atomic layer thermopile heat flux sensor from the test model during use; at this point, the atomic layer thermopile heat flux sensor packaging structure is completed.

[0021] The present invention includes at least the following beneficial effects: the packaging structure of the atomic layer thermopile heat flow sensor provided by the present invention avoids the difficulty of processing small holes with a large aspect ratio, effectively realizes the fixation of the sensor sensitive element, and achieves the purpose of test signal extraction and electrical insulation; and the packaging process of this packaging structure is simple and easy to operate, which facilitates the realization of the packaging structure.

[0022] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the packaging structure of the atomic layer thermopile heat flow sensor provided by the present invention;

[0024] Figure 2 This is a schematic diagram of the packaging structure of the sensitive element of the atomic layer thermopile heat flow sensor provided by the present invention. DETAILED DESCRIPTION

[0025] The present invention will be described in further detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0026] It should be understood that terms such as “having,” “including,” and “comprising” used herein do not prescribe the existence or addition of one or more other elements or combinations thereof.

[0027] like Figure 1-2As shown: A packaging structure of an atomic layer thermopile heat flow sensor of the present invention includes:

[0028] Base 3;

[0029] The packaging sleeve 2 is tightly fitted with the base 3; the sensitive element 1 is fixed on the base 3, and its outer surface is flush with the upper end surface of the packaging sleeve 2; the lead hole I6 is provided in the base 3;

[0030] The structure of the sensitive element includes: a strontium titanate wafer 7, on which a lead hole II 10 is opened, and the central axis of the lead hole II 10 coincides with the central axis of the lead hole I 6; a thermoelectric effect film 9, which is deposited on the strontium titanate wafer 7; a conductive gold film 8, which is deposited on the strontium titanate wafer 7 and covers the surface of the strontium titanate wafer around the lead hole II 10, and is located at both ends of the thermoelectric effect film 9;

[0031] A wire groove 5 is provided in the base 3 , and the lead hole I 6 is located between the sensitive element 1 and the wire groove 5 ; a silver wire 4 is fixed in the wire groove 5 , and the silver wire 4 passes through the lead hole I and the lead hole II and is electrically connected to the conductive gold film 8 .

[0032] Working Principle: The packaging structure of this atomic layer thermopile heat flux sensor is used to extract electrical signals directly related to high-frequency heat flux testing from shock tunnels and conventional hypersonic wind tunnels. The silver wire 4 is connected to the conductive gold film 8 of the sensitive element 1, and the test signal sensed by the sensitive element 1 is extracted from the shock tunnel and conventional hypersonic wind tunnel, thereby directly obtaining high-frequency pulsating heat flux. The base 3 provides a fixing mechanism for the sensitive element, which plays the role of fixing, supporting and protecting the sensitive element 1. The packaging sleeve further protects the sensitive element and achieves the purpose of electrical insulation from the experimental model during use of the sensor. When there is a temperature gradient between the upper and lower surfaces of the thermoelectric effect film 9, the transverse Seebeck effect generates a thermoelectric potential that is transverse and perpendicular to the temperature gradient between the upper and lower surfaces of the thermoelectric effect film 9. The atomic layer thermopile heat flux sensor obtained in this way needs to be statically calibrated to obtain its sensitivity coefficient. Its dynamic response time parameters can be calibrated using pulse-type experimental equipment such as shock tubes.

[0033] In the above technical solution, the packaging sleeve 2 is one of the insulating packaging sleeves such as polyetheretherketone packaging sleeve, aluminum nitride ceramic packaging sleeve, silicon nitride ceramic packaging sleeve, and alumina ceramic packaging sleeve; the base is an aluminum alloy base with anodized surface.

[0034] In the above technical solution, the thermoelectric effect film 9 is one of films having a lateral Seebeck effect, such as a yttrium barium copper oxide film and a lanthanum manganese copper oxide film.

[0035] In the above technical solution, the number of the wire grooves 5 and the number of the silver wires 4 are respectively set to two, and the wire grooves 5 are filled with glue, and the silver wires 4 are fixed in the base 3 by the glue.

[0036] In the above technical solution, conductive glue is applied between the silver wire 4 and the conductive gold film 8 to achieve electrical conduction between the silver wire 4 and the conductive gold film 8 .

[0037] In the above technical solution, the end surface of the silver wire 4 is flush with the outer surface of the sensitive element 1 .

[0038] In the above technical solution, the diameter of the strontium titanate wafer 7 is less than or equal to 6 mm, and the thickness is less than or equal to 0.5 mm; the diameter of the lead hole I and the lead hole II is 0.2 mm.

[0039] In the above technical solution, the packaging process of the atomic layer thermopile heat flow sensor packaging structure includes the following steps:

[0040] Step 1: Perform an anodic surface treatment on the aluminum alloy base; use mechanical processing or femtosecond laser processing to shape the strontium titanate wafer and open two lead holes II with a diameter of 0.2 mm at designated positions symmetrically in the center of the strontium titanate wafer; use an ion polishing process to treat the surface of the strontium titanate wafer; and deposit a yttrium barium copper oxide thin film and a conductive gold film on the strontium titanate wafer by physical vapor deposition to form the sensitive element of the atomic layer thermopile heat flow sensor;

[0041] Step 2: Fix the sensitive element 1 on the aluminum alloy base 3 by gluing, and ensure that the lead hole II10 is aligned with the lead hole I6 in the aluminum alloy base 3;

[0042] Step 3: Pass the silver wire 4 through the lead hole I6 and the lead hole II10, pour glue into the wire groove 5, and fix the silver wire 4 in the aluminum alloy base 3. Make sure that the silver wire 4 is completely immersed in the wire groove 5, and the end surface of the silver wire 4 is flush with the outer surface of the sensitive element 1;

[0043] Step 4: Apply conductive silver glue between the silver wire 4 and the conductive gold film 8 to achieve electrical conduction between the silver wire 4 and the conductive gold film 8;

[0044] Step 5. Put the polyetheretherketone packaging sleeve 2 on the aluminum alloy base 3, and ensure that the polyetheretherketone packaging sleeve 2 and the aluminum alloy base 3 are tightly fitted, and the upper end surface of the polyetheretherketone packaging sleeve 2 is flush with the outer surface of the sensitive element 1; the polyetheretherketone packaging sleeve 2 is used to further protect the sensitive element 1 and to electrically insulate the atomic layer thermopile heat flux sensor from the test model during use; at this point, the packaging structure of the atomic layer thermopile heat flux sensor is completed.

[0045] The number of devices and processing scales described herein are intended to simplify the description of the present invention. Applications, modifications, and variations of the present invention will be readily apparent to those skilled in the art.

[0046] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A packaging structure of an atomic layer thermopile thermal flow sensor, characterized in that: include: Pedestal; The packaging sleeve is tightly matched with the base; the sensitive element is fixed on the base, and its outer surface is flush with the upper end surface of the packaging sleeve; the lead hole I is arranged in the base; The structure of the sensitive element includes: a strontium titanate wafer, on which a lead hole II is opened, and the lead hole II coincides with the central axis of the lead hole I; a thermoelectric effect film, which is deposited on the strontium titanate wafer; a conductive gold film, which is deposited on the strontium titanate wafer and covers the surface of the strontium titanate wafer around the lead hole II and is located at both ends of the thermoelectric effect film; A wire groove is provided in the base, and the lead hole I is located between the sensitive element and the wire groove; a silver wire is fixed in the wire groove, and the silver wire passes through the lead hole I and the lead hole II, and is electrically connected with the conductive gold film; The packaging process of the packaging structure includes the following steps: Step 1: Perform an anodic surface treatment on the aluminum alloy base; perform molding processing on the strontium titanate wafer by mechanical processing or femtosecond laser processing, and open two lead holes II with a diameter of 0.2 mm at designated positions symmetrically in the center of the strontium titanate wafer; treat the surface of the strontium titanate wafer by ion polishing process, and deposit a yttrium barium copper oxide film and a conductive gold film on the strontium titanate wafer by physical vapor deposition, so as to form a sensitive element of the atomic layer thermopile heat flow sensor; Step 2: Fix the sensitive element on the aluminum alloy base by gluing, and ensure that the lead hole II is aligned with the lead hole I in the aluminum alloy base; Step 3: Pass the silver wire through lead hole Ⅰ and lead hole Ⅱ, pour glue into the wire groove, and fix the silver wire in the aluminum alloy base. Make sure that the silver wire is completely immersed in the wire groove, and the end face of the silver wire should be flush with the outer surface of the sensitive element; Step 4: Apply conductive silver glue between the silver wire and the conductive gold film to achieve electrical conduction between the silver wire and the conductive gold film; Step 5. Put the polyetheretherketone packaging sleeve on the aluminum alloy base, and ensure that the polyetheretherketone packaging sleeve and the aluminum alloy base are tightly fitted, and the upper end surface of the polyetheretherketone packaging sleeve is flush with the outer surface of the sensitive element; the polyetheretherketone packaging sleeve is used to further protect the sensitive element and to electrically insulate the atomic layer thermopile thermal flux sensor from the test model during use; at this point, the packaging structure of the atomic layer thermopile thermal flux sensor is completed.

2. The packaging structure of the atomic layer thermopile heat flow sensor according to claim 1, characterized in that: The packaging sleeve is one of insulating packaging sleeves such as a polyetheretherketone packaging sleeve, an aluminum nitride ceramic packaging sleeve, a silicon nitride ceramic packaging sleeve, and an alumina ceramic packaging sleeve; and the base is an aluminum alloy base with an anodized surface.

3. The packaging structure of the atomic layer thermopile heat flow sensor according to claim 1, characterized in that: The thermoelectric effect film is one of films having a lateral Seebeck effect, such as a yttrium barium copper oxide film and a lanthanum manganese copper oxide film.

4. The packaging structure of the atomic layer thermopile heat flow sensor according to claim 1, characterized in that: The number of the wire grooves and the number of the silver wires are respectively two, and the wire grooves are filled with glue, and the silver wires are fixed in the base by the glue.

5. The packaging structure of the atomic layer thermopile heat flow sensor according to claim 1, characterized in that: Conductive glue is applied between the silver wire and the conductive gold film to achieve electrical conduction between the silver wire and the conductive gold film.

6. The packaging structure of the atomic layer thermopile heat flow sensor according to claim 1, characterized in that: The end surface of the silver wire is flush with the outer surface of the sensitive element.

7. The packaging structure of the atomic layer thermopile heat flow sensor according to claim 1, characterized in that: The diameter of the strontium titanate wafer is less than or equal to 6 mm, and the thickness is less than or equal to 0.5 mm; the diameter of the lead hole I and the lead hole II is 0.2 mm.

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