CN115589760A - Micro-nano film heat flow sensor based on metal substrate and manufacturing method thereof - Google Patents

Abstract

The invention relates to a micro-nano film heat flow sensor based on a metal substrate and a manufacturing method thereof, belonging to the technical field of sensors. The sensor mainly comprises a metal substrate, a metal transition layer I, a metal bonding layer I, an insulating layer I, photoresist, a metal sensing layer, a metal transition layer II, a metal bonding layer II, an insulating layer II, a metal protection sheet, a metal transition layer III, a metal bonding layer III and epoxy resin; the manufacturing method comprises the following steps: selecting a metal substrate for sensor deposition; the transition layer, the bonding layer, the insulating layer, the sensing layer and the protective layer are deposited layer by layer through the process steps of electroplating, spin coating, photoetching, magnetron sputtering and the like to form a typical sandwich layered structure. The invention can effectively ensure the use effect of the sensor in severe industrial environment and is beneficial to greatly prolonging the service life of the sensor.

Description

Micro-nano film heat flow sensor based on metal substrate and manufacturing method thereof

Technical Field

The invention belongs to the technical field of sensors, and relates to a micro-nano film heat flow sensor based on a metal substrate and a manufacturing method thereof.

Background

Thermal field detection is a work which is frequently carried out in modern industrial production and scientific research processes, wherein two physical quantities of temperature and heat flow are mainly involved, and the latter often shows close correlation on physical mechanisms and has particularly prominent importance for fully understanding the dynamic change characteristics of the thermal field distribution and the heat transfer process and correctly analyzing related production process and product quality control influence factors. For the detection of heat flow, the traditional thermopile is difficult to be applied in some scenes with strict limitation on the size of an installation space and severe instantaneous dynamic change due to the defects of large size, slow response and the like, and even if the thermopile is barely used, the performance of the thermopile in the aspects of accuracy, reliability, timeliness, durability and the like is greatly reduced.

Disclosure of Invention

In view of the above, the present invention provides a micro-nano thin film heat flow sensor based on a metal substrate and a manufacturing method thereof.

In order to achieve the purpose, the invention provides the following technical scheme:

a micro-nano film heat flow sensor based on a metal substrate mainly comprises a metal base, a metal transition layer I, a metal bonding layer I, an insulating layer I, a metal sensing layer, a metal transition layer II, a metal bonding layer II, an insulating layer II, a metal protection plate, a metal transition layer III, a metal bonding layer III and epoxy resin.

The metal base is a substrate, and a metal transition layer I is electroplated on the surface of the metal base.

The thickness range of the metal substrate is 50-800 μm.

And a metal bonding layer I is sputtered on the surface of the metal transition layer I.

The thickness ranges of the metal bonding layer I and the metal bonding layer II are 10 nm-100 nm.

The thickness ranges of the metal transition layer I and the metal transition layer II are 5-30 mu m.

And the surface of the metal bonding layer I is coated with an insulating layer I.

The thickness ranges of the insulating layer I and the insulating layer II are 1-5 mu m.

And a metal transition layer II is electroplated on the surface of the metal sensing layer.

The metal sensing layer comprises a first pole sensing loop and a second pole sensing loop.

The thickness range of the metal sensing layer is 300 nm-900 nm.

The first pole sensing loop comprises a metal layer I, a metal layer II and a metal layer III which are deposited in sequence.

The second pole sensing loop is deposited on the surface of the first pole sensing loop and comprises a metal layer IV, a metal layer V and a metal layer VI which are sequentially deposited.

And a metal bonding layer II is sputtered on the surface of the metal transition layer II.

And the surface of the metal bonding layer II is coated with an insulating layer II.

And a metal protection sheet is adhered to the surface of the insulating layer II.

One surface of the metal protection plate is electroplated with a metal transition layer III, and the other surface is coated with epoxy resin.

And the insulating layer II is adhered to the surface of the metal bonding layer III, so that the metal substrate is adhered to the metal protection sheet.

And a metal bonding layer III is sputtered on the metal transition layer III.

A plurality of groups of thermopile loops are deposited on the high-temperature micro-nano film heat flow sensor based on the metal substrate, and multi-point detection in a local area is realized. One group of thermopile loops comprises a metal sensing layer, a metal transition layer II, a metal bonding layer II, an insulating layer II and a metal protection sheet which are deposited in sequence.

The micro-nano film heat flow sensor based on the metal substrate can resist the temperature of 400 ℃.

The micro-nano film heat flow sensor based on the metal substrate detects heat flow by collecting potential signals.

A manufacturing method of a micro-nano film heat flow sensor based on a metal substrate mainly comprises the following steps:

step 1, selecting a metal substrate for sensor deposition.

The roughness range of the surface of the metal substrate is 100 nm-400 nm.

And 2, grinding and chemically and mechanically polishing the metal substrate, and depositing a metal transition layer I on the surface of the metal substrate by a magnetron sputtering process.

And 3, depositing a metal bonding layer I on the surface of the metal transition layer I through a magnetron sputtering process.

And 4, coating an insulating layer I on the surface of the metal bonding layer I by a glue-homogenizing spin-coating process, and respectively carrying out soft baking and curing in a hot plate and an oven.

And 5, coating photoresist on the surface of the insulating layer I through a photoresist homogenizing and spin coating process, and performing pre-baking on the metal substrate on a hot plate. And exposing on a photoetching machine by adopting a mask plate. After exposure, the metal substrate was post-baked on a hot plate. And (3) placing the metal substrate in a developing solution for developing, and drying to obtain the sensor plate.

And 6, depositing a metal sensing layer on the surface of the photoresist layer by a magnetron sputtering process, which mainly comprises the following steps:

and 6.1, sequentially depositing a metal layer I, a metal layer II and a metal layer III on the surface of the photoresist layer to form a first pole sensing loop.

And 6.2, sequentially depositing a metal layer IV, a metal layer V and a metal layer VI on the surface of the first pole sensing loop to form a second pole sensing loop, placing the second pole sensing loop in acetone, soaking, stripping photoresist and drying.

And 7, cutting out the metal protection sheet based on the sensor plate.

The metal protection sheet is in a circular crown shape.

And 8, depositing a metal transition layer III on the surface of the metal protection plate by adopting an electroplating process, and depositing a metal bonding layer III on the surface of the metal transition layer III by adopting a magnetron sputtering process.

And 9, coating an insulating layer II on the surface of the metal sensing layer by a spin coating process.

And step 10, adhering the metal protection sheet to the metal substrate by utilizing the adhesive property of the insulating layer II, and exposing the bonding pad.

And 11, baking and curing the metal substrate attached with the metal protection sheet, and removing the insulating layer on the surface of the bonding pad by a plasma etching process.

And step 12, connecting the bonding pad and the compensation wire by adopting conductive silver adhesive, and coating epoxy resin on the surface after baking by a hot plate. And curing the epoxy resin.

The diameter range of the compensating lead is 0.2 mm-0.5 mm.

The micro-nano film heat flow sensor is manufactured based on an ultra-clean space MEMS micro-electro-mechanical system processing technology, wherein the main processing links relate to photoetching, magnetron sputtering, electron beam evaporation, atomic layer stacking and other technologies, the micro-nano film heat flow sensor is a relatively more advanced and advanced sensor technology, the thickness of a working layer is only hundreds of nanometers generally, a protective layer is not more than 1mm generally, the line width and the node size of the working layer are both in a micron order, the technical characteristics of convenience and flexibility in installation, rapid dynamic response, real and reliable detection and the like are given by the small-size characteristic, a plurality of detection points can be reasonably arranged in a local smaller area through line optimization design, the technical limits of a traditional detection assembly in the aspects can be obviously improved, in addition, the high-temperature and high-pressure resistant severe environment capacity and the service life of the film sensor can be greatly improved by adopting a metal substrate with high hardness, high melting point and good heat conductivity as the protective layer, and an important hardware basis is further provided for further optimization and enrichment of detection means in various industrial scenes.

Based on the classical Seebeck effect and the thermopile principle that a plurality of groups of K-type thermocouples are connected in series, micro-nano film heat flow sensors which have a typical sandwich layer packaging structure and can resist the high temperature of 400 ℃ are manufactured by using MEMS micro-electro-mechanical processing technologies such as spin coating, photoetching development, magnetron sputtering and the like in an ultra-clean room and using metals with relatively high melting point and hardness and good heat conduction and electrical conductivity as substrate substrates.

The technical effects of the invention are undoubtedly that the micro-nano film sensor disclosed by the invention has small size, quick response and small disturbance to an original thermal field, can timely and accurately capture the transient dynamic change of the thermal field, acquire transient heat flow, can be flexibly and conveniently installed in a narrow space and closer to a point to be detected for detection, and can simultaneously arrange a plurality of thermopile loops in a detection area according to requirements to realize local multi-point detection; the packaging mode based on the metal substrate with relatively high melting point hardness and good heat conduction and electric conductivity enables the sensor to have good high-temperature and high-pressure resistance and anti-interference performance, can effectively guarantee the use effect of the sensor in severe industrial environment, and is beneficial to greatly prolonging the service life of the sensor.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.

Drawings

For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic diagram of a micro-nano film heat flow sensor.

FIG. 2 is a schematic diagram of the structure of the substrate after nickel electroplating.

FIG. 3 is a schematic view of the structure of the substrate after sputtering titanium.

FIG. 4 is a schematic diagram of the structure of the substrate after the spin coating of polyimide.

Fig. 5 is a schematic diagram of the exposure & development process steps.

FIG. 6 is a schematic diagram of sputter depositing a metal sensing layer.

FIG. 7 is a schematic diagram of the completed deposition of a two-pole sensing loop.

FIG. 8 is a schematic diagram of a sandwich layer package structure after RIE etching.

Fig. 9 is a schematic diagram of a core working layer of the micro-nano film heat flow sensor.

Fig. 10 is a schematic structural diagram of a metal sheet required for a sensor package.

Reference numerals: the temperature-sensing device comprises a metal substrate 1, a metal transition layer 2, a metal transition layer I, a metal bonding layer 3, an insulating layer 4, a photoresist 5, a metal sensing layer 6, a metal sensing layer 601, a metal layer I, a metal layer 602, a metal layer II, a metal layer III, a metal layer IV 604, a metal layer V605, a metal layer VI, a metal protective sheet 7, a compensation lead 8, a pad 9, a metal transition layer 10, a metal bonding layer 11, an insulating layer 12, a metal transition layer III, a metal bonding layer 14, epoxy resin 15, an A-cathode, an anode B, a temperature-sensing contact at the lower end of T0 and a temperature-sensing contact at the upper end of T1.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.

Wherein the showings are for the purpose of illustrating the invention only and not for the purpose of limiting the same, and in which there is shown by way of illustration only and not in the drawings in which there is no intention to limit the invention thereto; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that, if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the drawings, it is only for convenience of description and simplicity of description, but does not indicate or imply that the device or component referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationships in the drawings are only used for illustrative purposes and are not to be construed as limiting the present invention, and those skilled in the art can understand the specific meanings of the terms according to specific situations.

Example 1:

referring to fig. 1 to 10, a micro-nano film heat flow sensor based on a metal substrate mainly includes a metal base (1), a metal transition layer I (2), a metal bonding layer I (3), an insulating layer I (4), a photoresist (5), a metal sensing layer (6), a metal transition layer II (10), a metal bonding layer II (11), an insulating layer II (12), a metal protection sheet (7), a metal transition layer III (13), a metal bonding layer III (14), and an epoxy resin (15).

The metal base (1) is a substrate, and a metal transition layer I (2) is electroplated on the surface of the metal base. The metal substrate (1) is made of copper.

And a metal bonding layer I (3) is sputtered on the surface of the metal transition layer I (2). The material of the bonding layer is titanium.

And the surface of the metal bonding layer I (3) is coated with an insulating layer I (4).

When the insulating layer I (4) is manufactured, the surface of the insulating layer I (4) is coated with photoresist (5).

And a metal sensing layer (6) is deposited on the surface of the photoresist (5).

And a metal transition layer II (10) is electroplated on the surface of the metal sensing layer (6).

The metal sensing layer (6) comprises a first pole sensing loop and a second pole sensing loop.

The first pole sensing loop comprises a metal layer I (601), a metal layer II (602) and a metal layer III (603) which are deposited in sequence.

The second pole sensing loop is deposited on the surface of the first pole sensing loop and comprises a metal layer IV (604), a metal layer V (605) and a metal layer VI (606) which are sequentially deposited. The metal layer I (601), the metal layer III (603), the metal layer IV (604), and the metal layer VI (606) are adhesive layers for improving adhesion between the upper layer and the lower layer.

And a metal bonding layer II (11) is sputtered on the surface of the metal transition layer II (10).

And the surface of the metal bonding layer II (11) is coated with an insulating layer II (12).

And a metal protection sheet (7) is adhered to the surface of the insulating layer II (12).

One surface of the metal protection sheet (7) is electroplated with a metal transition layer III (13), and the other surface is coated with epoxy resin (15).

And the insulating layer II (12) is adhered to the surface of the metal bonding layer III (14), so that the metal substrate (1) is adhered to the metal protection sheet (7).

The metal transition layer III (13) is sputtered with a metal bonding layer III (14).

A plurality of groups of thermopile loops are deposited on the high-temperature micro-nano film heat flow sensor based on the metal substrate, and multi-point detection in a local area is realized. One group of thermopile loops comprise a metal sensing layer (6), a metal transition layer II, a metal bonding layer II, an insulating layer II and a metal protection sheet (7) which are deposited in sequence.

The micro-nano film heat flow sensor based on the metal substrate can resist the temperature of 400 ℃.

The micro-nano film heat flow sensor based on the metal substrate detects heat flow by collecting potential signals.

Example 2:

a micro-nano film heat flow sensor based on a metal substrate has a main structure shown in an embodiment 1, wherein,

the thickness of the metal substrate (1) is 50 μm;

the thicknesses of the metal transition layer I (2) and the metal transition layer II (10) are 5 mu m;

the thicknesses of the metal bonding layer I (3) and the metal bonding layer II (11) are 10nm;

the thickness of the insulating layer I (4) and the insulating layer II (12) is 1 μm;

the thickness of the metal sensing layer (6) is 300nm.

Example 3:

a micro-nano film heat flow sensor based on a metal substrate has the main structure shown in embodiment 1, wherein,

the thickness of the metal substrate (1) is 800 μm;

the thicknesses of the metal transition layer I (2) and the metal transition layer II (10) are 30 mu m;

the thicknesses of the metal bonding layer I (3) and the metal bonding layer II (11) are 100nm;

the thickness of the insulating layer I (4) and the insulating layer II (12) is 5 μm;

the thickness of the metal sensing layer (6) is 900nm.

Example 4:

a micro-nano film heat flow sensor based on a metal substrate has the main structure shown in embodiment 1, wherein,

the thickness of the metal substrate (1) is 425 μm;

the thicknesses of the metal transition layer I (2) and the metal transition layer II (10) are 17.5 mu m;

the thicknesses of the metal bonding layer I (3) and the metal bonding layer II (11) are 55nm;

the thickness of the insulating layer I (4) and the insulating layer II (12) is 3 μm;

the thickness of the metal sensing layer (6) is 600nm.

Example 5:

a micro-nano film heat flow sensor based on a metal substrate mainly comprises the following components:

the method comprises the following steps of taking metal as a substrate of a sensor, and depositing a transition layer, a bonding layer, an insulating layer, a sensing layer and a protective layer by layer through electroplating, spin coating, photoetching, magnetron sputtering and other process steps to form a typical sandwich layered structure; the design of the sensing layer is based on a thermopile principle, namely, a plurality of K-type thermocouples are connected in series, two different nickel-based alloys are used as two-pole materials for forming a thermocouple loop, and a detection point heat flow value is obtained by acquiring and reading an amplified thermoelectromotive force signal; multiple groups of thermopile loops can be deposited on a sensing layer of the same substrate, multi-point detection in a narrow local area is achieved, the spatial resolution is high, even if one detection point is damaged, the rest other detection points can still work normally, and the detection redundancy is good; the thickness of the sensor film is only hundreds of nanometers, the line width and the size of a hot junction are small, the mass and the heat capacity are small, the response to the rapid change of a thermal field is rapid, the response time can reach microsecond level, and the interference and the destructiveness to the real thermal field of a detection point are small; the sensor adopts metal with good electrical conductivity and thermal conductivity as a protective layer, and adopts a high polymer insulating material with good thermal stability and mechanical property as an insulating layer, so that heat flow detection in an environment of 400 ℃ can be reliably realized; a layer of metal which is similar to the substrate and has better heat conduction and electrical conductivity and strength is electroplated on the substrate base as a transition layer; a layer of metal is respectively sputtered on the upper surface and the lower surface of the sensing layer alloy material to be used as a bonding layer, so that the bonding property between the sensing layer and the insulating layer is effectively enhanced, and the layering phenomenon is prevented; the sensor bonding pad adopts a high-temperature-resistant conductive bonding material as a lead connecting material, so that the reliability and stability of the sensor used in a long-term high-temperature environment can be ensured.

The substrate base plate for manufacturing the sensor is made of metal with good electrical conductivity and thermal conductivity and relatively high melting point and hardness.

The sensor is a typical sandwich layered structure and comprises a transition layer, a bonding layer, an insulating layer, a sensor and a protective layer, and the sensor is deposited layer by layer sequentially through the processes of electroplating, spin coating, photoetching, magnetron sputtering and the like. Wherein, the thickness of the transition layer is 5-30 μm, the thickness of the bonding layer is 10-100 nm, the thickness of the insulating layer is 1-5 μm, and the thickness of the sensing layer is 300-900 nm.

The design of the sensor is based on the thermopile principle of serially connecting multiple groups of K-type thermocouples, and NiCr-NiAlMnSi, niCr-NiAl and NiCr-NiSi alloys are used as two-pole materials for forming a thermocouple loop.

And a plurality of groups of thermopile loops are simultaneously deposited on the sensing layer of the same substrate, so that multi-point detection in a narrow local area is realized.

The thickness of the sensor film is hundreds of nanometers, the line width and the size of the hot junction are small, the mass and the heat capacity are small, the transient change of the thermal field can be reflected quickly, the response time can reach microsecond level, and the destructive interference on the real thermal field of the detection point is small.

The sensor adopts polyimide with better thermal stability and mechanical property as an insulating layer, and can reliably realize heat flow detection in an environment of 400 ℃.

A layer of metal titanium is sputtered on the surface of the transition layer to serve as a bonding layer, so that the bonding property of the metal substrate and the insulating layer is effectively enhanced.

A layer of metal titanium is sputtered on the upper portion and the lower portion of the sensing layer of the sensor respectively to serve as a bonding layer, and therefore the bonding performance between the sensing layer and the insulating layer is effectively enhanced.

The sensor bonding pad adopts bi-component conductive silver adhesive as a wire connecting material, so that the reliability and stability of the sensor used in a long-term high-temperature environment can be ensured.

The cathode of the micro-nano film heat flow sensor of the metal substrate is marked as A, the anode of the micro-nano film heat flow sensor of the metal substrate is marked as B, the temperature sensing contact at the upper end of the micro-nano film heat flow sensor is marked as T1, and the temperature sensing contact at the lower end of the micro-nano film heat flow sensor of the metal substrate is marked as T0.

Example 6:

a manufacturing method of a micro-nano film heat flow sensor based on a metal substrate mainly comprises the following steps:

1) A metal substrate (1) is selected for sensor deposition.

The surface roughness range of the metal substrate (1) is 100 nm-400 nm.

2) Grinding and chemically mechanical polishing are carried out on the metal substrate (1), and a metal transition layer I (2) is deposited on the surface of the metal substrate (1) through a magnetron sputtering process.

3) And depositing a metal bonding layer I (3) on the surface of the metal transition layer I (2) by a magnetron sputtering process.

4) And coating an insulating layer I (4) on the surface of the metal bonding layer I (3) by a glue-homogenizing spin coating process, and respectively carrying out soft baking and curing in a hot plate and an oven.

5) And coating photoresist (5) on the surface of the insulating layer I (4) by a spin coating process, and prebaking the metal substrate (1) on a hot plate. And exposing on a photoetching machine by adopting a mask plate. After exposure, the metal base 1 is subjected to post-baking on a hot plate. And (3) placing the metal substrate (1) in a developing solution for developing, and drying to obtain the sensor plate.

6) Depositing a metal sensing layer (6) on the surface of the photoresist layer by a magnetron sputtering process, which mainly comprises the following steps:

6.1 Metal layer I (601), metal layer II (602), and metal layer III (603) are sequentially deposited on the photoresist layer surface to form a first pole sensing loop.

6.2 A metal layer IV (604), a metal layer V (605) and a metal layer VI (606) are sequentially deposited on the surface of the first pole sensing loop to form a second pole sensing loop, and then the second pole sensing loop is placed in acetone to be soaked and stripped of photoresist (5) and dried.

7) Based on the sensor plate, a metal protective sheet (7) is cut out.

The metal protection sheet (7) is in a circular crown shape.

8) And depositing a metal transition layer III (13) on the surface of the metal protection plate (7) by adopting an electroplating process, and depositing a metal bonding layer III (14) on the surface of the metal transition layer III (13) by adopting a magnetron sputtering process.

9) And coating an insulating layer II (12) on the surface of the metal sensing layer (6) by a glue-homogenizing spin-coating process.

10 A metal protective sheet (7) is bonded to the metal base sheet (1) by the adhesion of the insulating layer II, and the bonding pad (9) is exposed.

11 Baking and curing the metal substrate (1) adhered with the metal protection sheet (7), and removing the insulating layer on the surface of the bonding pad (9) by a plasma etching process.

12 The bonding pad (9) is connected with the compensating lead (8) by adopting conductive silver adhesive, and then epoxy resin is coated on the surface after the bonding pad is baked by a hot plate. The epoxy resin (15) is cured.

The diameter range of the compensating lead (8) is 0.2 mm-0.5 mm.

Example 7:

a manufacturing method of a micro-nano film heat flow sensor based on a metal substrate mainly comprises the following steps:

1) According to the requirement of heat flow detection, a micro-nano film heat flow sensor is designed and manufactured, wherein the shape, the size and the number of the sensor are shown in figure 1.

2) The metal with the diameter of 4' and the thickness of 800 μm is used as a substrate for sensor deposition, and a metal transition layer with the thickness of 5 μm-30 μm is deposited on the surface of a copper sheet after polishing and grinding, as shown in figure 2.

3) And depositing a layer of metal titanium with the thickness of 10 nm-100 nm on the surface of the transition layer by a magnetron sputtering process, wherein the metal titanium is shown in figure 3.

4) Coating an organic polymer material polyimide with the thickness of 1-5 μm on the surface of the titanium layer by a spin coating process, and respectively soft-baking and curing in a hot plate and an oven, as shown in figure 4.

5) The method comprises the steps of coating photoresist with the thickness of 1-5 microns on the surface of an insulating layer through a photoresist homogenizing and spin coating process, carrying out pre-baking on a hot plate, carrying out exposure on a photoetching machine by using a mask plate, then placing the photoetching machine on the hot plate for post-baking, then placing the photoetching machine in a developing solution for developing, and forming a sensor shape and size chart after cleaning and blow-drying, wherein the chart is shown in figure 5.

6) Three layers of metal, namely metal titanium with the thickness of 10 nm-100 nm, nickel-based alloy with the thickness of 300 nm-900 nm and metal titanium with the thickness of 10 nm-100 nm are sequentially deposited on the surface of the photoresist layer through a magnetron sputtering process, and a first pole sensing loop is formed.

7) Repeating the above process steps, depositing the metal titanium, the other electrode nickel-based alloy and the metal titanium in sequence to form a second electrode sensing loop, placing the second electrode sensing loop in acetone to soak and strip the photoresist, and drying the photoresist, as shown in fig. 6 and 7.

8) And cutting the protective layer metal sheet in a circular crown shape according to the size characteristics of the sensor, and sequentially and respectively depositing the transition layer and the bonding layer by adopting an electroplating process and a magnetron sputtering process.

9) And coating polyimide with the thickness of 1-5 microns on the manufactured sensing layer by a spin coating process, attaching the copper sheet processed in the previous step to the substrate by using the adhesiveness of the polyimide, just exposing the bonding pad, baking and curing to form a sandwich layer-shaped packaging structure, and finally removing the insulating layer on the surface of the bonding pad by a plasma etching process to expose the bonding pad for a lead, wherein the structure is shown in figure 8.

10 Adopting conductive silver adhesive to connect compensation wires to all the bonding pads on the sensing layer, coating a layer of epoxy resin after baking and curing by a hot plate, and finishing the manufacture of the whole sensor after aging and curing for 10-36 hours, wherein the heat flow is detected by collecting potential signals, and the sensing layer is the core working layer of the sensing layer, which is shown in figure 9.

Example 8:

a manufacturing method of a micro-nano film heat flow sensor based on a metal substrate mainly comprises the following steps:

1) Firstly, micro-nano film heat flow sensors are designed according to the requirements of heat flow detection, as shown in fig. 1, wherein the micro-nano film heat flow sensors include the shapes, sizes and numbers of the sensors. The design of the sensor is based on the thermoelectric principle of the Seebeck effect and the thermopile principle of serially connecting a plurality of groups of K-type thermocouples, namely: two different conductors are respectively used as an anode and a cathode, two ends of the two different conductors are tightly connected with each other to form a closed loop, and when the temperatures of two joints are unequal, T1 is more than T0, electromotive force can be generated in the loop, so that hot current is formed; a plurality of groups of thermocouples with the same physical property are connected in series to form a thermopile, so that the temperature difference potential between two points in the heat transfer direction is amplified, and the amplification factor depends on the number of the series groups. One key indicator of the thermopile is sensitivity, i.e., the output of thermoelectric force under unit heat flow, the value of which depends on the thermal conductivity of the substrate material, the number of the thermocouple series groups and the distance between the upper and lower temperature sensing contacts, and satisfies that a good design must ensure a sufficiently large sensitivity. The sensor adopts a thermopile formed by connecting a plurality of groups of K-type thermocouples in series, and K-type thermocouple alloy is selected as a sensing layer. The method is characterized in that a plurality of groups of sensors are arranged on a substrate according to requirements, each group of sensors can be provided with a plurality of pairs of thermocouple thermopile loops, the loop routing design is symmetrical and attractive as much as possible and is convenient for cutting and processing, meanwhile, the success rate of sensor manufacturing is also considered when the plane size of the sensors is considered, namely, the line width size of a single electrode and the distance between each pair of electrodes are not small, and in addition, in order to reduce the difficulty of lead connection and ensure the insulation between each pair of bonding pads, the side length size of a single square bonding pad and the distance between each pair of bonding pads are not small.

2) The copper sheet with the diameter of 4' and the thickness of 800 μm is used as a substrate for sensor deposition, the melting point of the copper is about 1083 ℃, the boiling point is about 2567 ℃, the Vickers hardness is about 350MPa, the copper sheet has good ductility and heat conduction performance, and is a less active heavy metal, and the copper sheet is suitable to be selected as a protective layer in consideration of both heat conduction performance and material strength. After the copper sheet is polished and polished, the copper sheet is subjected to pretreatment such as substrate cleaning and transition layer deposition, and the defects of low surface roughness, smooth surface, no obvious scratch pit and the like are ensured.

In order to enhance the bonding between the metal substrate and the subsequent insulating layer, a layer of metal titanium with a thickness of 10nm to 100nm needs to be deposited on the surface of the transition layer as a bonding layer through a magnetron sputtering process, as shown in fig. 3, if the surface of the substrate is rough, the deposition thickness can be increased properly. So-called sputtering, i.e. bombarding the surface of a solid target with a plasma having kinetic energy of more than a few tens of electron volts, atoms near the surface acquire part of the energy carried by the incident particles, and when sufficient to overcome the binding energy, these atoms detach from the solid and enter the vacuum chamber, where they are subsequently deposited on the substrate. The specific sputtering technological parameters are as follows: the sputtering power is 200W-600W, the sputtering speed is 10 nm/min-20 nm/min, and the sputtering time is 2 min-6 min, and parameters can be adjusted for different equipment platforms.

3) And then an insulating layer is required to be manufactured, namely a layer of polyimide is coated on the surface of the titanium layer through a glue homogenizing and spin coating process, the polyimide has good comprehensive thermal and mechanical properties, the thermal decomposition temperature is as high as 500-600 ℃, the long-term use temperature range is-200-300 ℃, no obvious melting point exists, the polyimide can be one of polymers with the best thermal stability, and meanwhile, the polyimide has excellent mechanical properties and thermal aging resistance, the tensile strength is about 170-400 MPa, the elastic modulus is about 3-4 GPa, the tensile strength after aging treatment for 200 ℃ and 1500 hours is reduced a little, the polyimide has high insulating property, the dielectric constant is usually about 3.4, the dielectric loss is only 0.004-0.007, and the polyimide belongs to F-H-grade insulating materials. First, spin coating is performed on a substrate using a spin coater. Then, soft baking was performed on a hot plate. Then, baking and curing are carried out in an oven. Based on the comprehensive consideration of good heat conduction and insulation protection, the thickness of the insulation layer is controlled to be 0.5-5 μm after baking and curing.

4) In order to manufacture the designed sensor plate to perform the next sputtering deposition of the metal sensing layer, a photoresist with a thickness of 1-5 μm needs to be coated on the surface of the insulating layer by a spin coating process. A pre-bake is then performed on a hot plate to remove the solvent from the photoresist to enhance adhesion. Next, the pre-baked substrate is placed on a lithography machine for exposure. After exposure, the substrate is placed on a hot plate for post-baking to excite acid generated by PAG photosensitive acid generator of the chemically enhanced photoresist to react with the protective group on the photoresist and remove the group so that the group can be dissolved in a developing solution, and meanwhile, the standing wave effect is reduced. And then, placing the baked substrate into a developing solution for developing, after the developing is finished, cleaning the substrate by using deionized water, and drying the substrate by using nitrogen to finally form a plate with the shape and the size of the sensor, as shown in fig. 5.

5) Next, the most core metal sensing layer is fabricated. Firstly, sputtering a layer of metal titanium with the thickness of 10 nm-100 nm according to the process method in the step 3. And depositing a layer of nickel base alloy with the thickness of 300-900 nm by magnetron sputtering, wherein the specific sputtering process parameters are as follows: the sputtering power is 200W-600W, the sputtering speed is 10 nm/min-20 nm/min, the sputtering time is 30 min-80 min, and parameters can be adjusted for different equipment platforms. Then, sputtering a layer of metal titanium with the thickness of 10-100 nm according to the process method in the step 3. After the deposition is completed, the deposition of the first pole sensing loop is completed, as shown in fig. 6.

6) Repeating the above process steps, and sputtering and depositing a layer of metal titanium with the thickness of 10 nm-100 nm. Then sputtering and depositing another nickel base alloy layer with the thickness of 300 nm-900 nm, wherein the specific sputtering technological parameters are as follows: the sputtering power is 200W-600W, the sputtering speed is 10 nm/min-20 nm/min, the sputtering time is 30 min-80 min, and parameters can be adjusted for different equipment platforms. Then a layer of metal titanium with the thickness of 10nm to 100nm is sputtered and deposited. And finishing the deposition of the second pole sensing loop after the deposition is finished, and cleaning and drying after the photoresist is soaked and stripped, as shown in fig. 7. At this point, the fabrication of the most core sensing layer is completed.

7) In order to prevent the thin film sensor from being worn and corroded in a severe environment to enhance the durability of the thin film sensor, the thin film sensor needs to be packaged and protected. Firstly, cutting a copper sheet in a circular crown shape according to the size characteristics of a sensor, then sequentially and respectively depositing a transition layer metal with the thickness of 5-30 microns and a bonding layer metal titanium with the thickness of 10-100 nm on the surface of the copper sheet by adopting an electroplating process and a magnetron sputtering process, and preparing for the next packaging, as shown in figure 10.

8) And then, firstly, coating polyimide with the thickness of 1-5 microns on the manufactured sensing layer by a glue-homogenizing and spin-coating process, attaching the copper sheet prepared in the last step to the substrate by utilizing the adhesiveness of the polyimide, just exposing the bonding pad part, then baking and curing in an oven to form a sandwich layer-shaped packaging structure, and finally removing the insulating layer on the surface of the bonding pad by a plasma etching process to expose the bonding pad for a lead.

9) And the last connecting step is carried out. Firstly, conductive silver adhesive is adopted to connect all the pads on the sensing layer with compensation wires with the diameter of 0.2 mm-0.5 mm, then a layer of epoxy resin is coated to cover the compensation wires after hot plate baking so as to reduce the influence of external force on the joint of the connecting wires and the pads and prevent the disconnection of the connecting wires, and then the whole sensor is manufactured after aging curing for 10 hours-36 hours, wherein the heat flow is detected by collecting potential signals, and the sensing layer is the core working layer of the sensor, which is shown in figure 9.

The micro-nano film sensor based on the metal substrate has small size, quick response and small interference to an original thermal field, can timely and accurately capture the instantaneous dynamic change of the thermal field, acquire transient heat flow, can be flexibly and conveniently installed in a narrow space and closer to a point to be detected for detection, and can simultaneously arrange a plurality of thermopile loops in a detection area according to requirements to realize local multi-point detection; based on the sandwich layer packaging structure mode of the metal copper substrate with relatively high melting point hardness and good heat conduction and electric conductivity, the sensor has good high-temperature and high-pressure resistance and anti-interference performance, can effectively avoid abrasion and corrosion, can effectively ensure the use effect of the film sensor in severe industrial environment, and is beneficial to greatly improving the durability and the service life of the film sensor. The invention can obviously improve the technical limitations and disadvantages of the traditional heat flow detection assembly in the aspects of space size, dynamic response, packaging protection and the like, provides important hardware basis and technical means for the optimization and innovation of the traditional heat flow detection mode, and is worthy of being popularized and applied in various heat flow detection fields.

Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.

Claims (8)

1. A micro-nano film heat flow sensor based on a metal substrate is characterized in that: the sensor mainly comprises a metal substrate (1), a metal transition layer I (2), a metal bonding layer I (3), an insulating layer I (4), a metal sensing layer (6), a metal transition layer II (10), a metal bonding layer II (11), an insulating layer II (12), a metal protection sheet (7), a metal transition layer III (13) and epoxy resin (15);

the metal base (1) is a substrate, and a metal transition layer I (2) is electroplated on the surface of the metal base;

a metal bonding layer I (3) is sputtered on the surface of the metal transition layer I (2);

the surface of the metal bonding layer I (3) is coated with an insulating layer I (4);

a metal sensing layer (6) is deposited on the surface of the insulating layer I (4);

a metal transition layer II (10) is electroplated on the surface of the metal sensing layer (6);

the metal sensing layer (6) comprises a first pole sensing loop and a second pole sensing loop;

the first pole sensing loop comprises a metal layer I (601), a metal layer II (602) and a metal layer III (603) which are deposited in sequence;

the second pole sensing loop is deposited on the surface of the first pole sensing loop and comprises a metal layer IV (604), a metal layer V (605) and a metal layer VI (606) which are sequentially deposited;

a metal bonding layer II (11) is sputtered on the surface of the metal transition layer II (10);

the surface of the metal bonding layer II (11) is coated with an insulating layer II (12);

a metal protection sheet (7) is adhered to the surface of the insulating layer II (12);

and a metal transition layer III (13) is electroplated on the lower surface of the metal protection plate (7) opposite to the insulating layer II (12), and epoxy resin (15) is coated on the other surface.

2. The metal substrate-based micro-nano film heat flow sensor according to claim 1, wherein a metal bonding layer III (14) is sputtered on the surface of the metal transition layer III (13), and the insulating layer II (12) is bonded to the surface of the metal bonding layer III (14), so that the metal base (1) is bonded to the metal protection sheet (7).

3. The metal substrate-based micro-nano film heat flow sensor according to claim 1, characterized in that:

the thickness range of the metal substrate (1) is 50-800 μm;

the thickness ranges of the metal transition layer I (2) and the metal transition layer II (10) are 5-30 mu m;

the thickness ranges of the metal bonding layer I (3) and the metal bonding layer II (11) are 10 nm-100 nm;

the thickness ranges of the insulating layer I (4) and the insulating layer II (12) are 1-5 mu m;

the thickness range of the metal sensing layer (6) is 300 nm-900 nm.

4. A method for manufacturing a micro-nano film heat flow sensor based on a metal substrate is characterized by mainly comprising the following steps:

step 1, selecting a metal base (1) for sensor deposition as a substrate;

step 2, grinding and chemically mechanical polishing the metal substrate (1), and depositing a metal transition layer I (2) on the surface of the metal substrate (1) through a magnetron sputtering process;

step 3, depositing a metal bonding layer I (3) on the surface of the metal transition layer I (2) through a magnetron sputtering process;

step 4, coating an insulating layer I (4) on the surface of the metal bonding layer I (3) through a glue-homogenizing and spin-coating process, and respectively performing soft baking and curing in a hot plate and an oven;

step 5, coating photoresist (5) on the surface of the insulating layer I (4) through a spin coating process, and pre-baking the metal substrate (1) on a hot plate; exposing on a photoetching machine by adopting a mask plate; after exposure, post-baking the metal substrate (1) on a hot plate; placing the metal substrate (1) in a developing solution for developing, and drying to obtain a sensor plate;

step 6, depositing a metal sensing layer (6) on the surface of the photoresist layer through a magnetron sputtering process;

step 7, cutting out a metal protection sheet (7) based on the sensor plate;

step 8, depositing a metal transition layer III (13) on one surface of the metal protection plate (7) by adopting an electroplating process, and depositing a metal bonding layer III (14) on the surface of the metal transition layer III (13) by adopting a magnetron sputtering process;

step 9, coating an insulating layer II (12) on the surface of the metal sensing layer (6) through a glue-homogenizing spin-coating process;

step 10, adhering the surfaces of a metal transition layer III (13) and a metal bonding layer III (14) deposited on a metal protection plate (7) to a metal substrate (1) by utilizing the adhesiveness of an insulating layer II (12), and exposing a bonding pad (9);

step 11, baking and curing the metal substrate (1) attached with the metal protection sheet (7), and removing the insulating layer on the surface of the bonding pad (9) by a plasma etching process;

step 12, connecting the bonding pad (9) with the compensation lead (8) by adopting conductive silver adhesive, and then coating epoxy resin (15) on the surface after baking by a hot plate; the epoxy resin (15) is cured.

5. The manufacturing method of the metal substrate-based micro-nano film heat flow sensor according to claim 4, wherein the magnetron sputtering process deposits the metal sensing layer (6) on the surface of the photoresist layer, and the main steps are as follows:

step 6.1, sequentially depositing a metal layer I (601), a metal layer II (602) and a metal layer III (603) on the surface of the photoresist layer to form a first pole sensing loop;

and 6.2, sequentially depositing a metal layer IV (604), a metal layer V (605) and a metal layer VI (606) on the surface of the first pole sensing loop to form a second pole sensing loop, placing the second pole sensing loop in acetone, soaking and stripping the photoresist (5), and drying.

6. The manufacturing method of the metal substrate-based micro-nano film heat flow sensor according to claim 4, wherein the surface roughness of the metal base (1) ranges from 100nm to 400nm.

7. The method for manufacturing the metal substrate based micro-nano thin film heat flow sensor according to claim 4, wherein the metal protection sheet (7) is in a shape of a circular crown.

8. The manufacturing method of the metal substrate-based micro-nano film heat flow sensor according to claim 4, wherein the diameter range of the compensation wire (8) is 0.2 mm-0.5 mm.

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