CN115589760A - A metal substrate-based micro-nano film heat flow sensor and its manufacturing method - 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

A metal substrate-based micro-nano film heat flow sensor and its manufacturing method

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 technique

Thermal field detection is a work that is often carried out in the process of modern industrial production and scientific research. It mainly involves two physical quantities of temperature and heat flow. A full understanding of the thermal field distribution and dynamic change characteristics of the heat transfer process, as well as related production processes and The correct analysis of the influencing factors of product quality control, the latter often can better reflect the close correlation in the physical mechanism, is particularly important. For the detection of heat flow, due to the shortcomings of large size and slow response, traditional thermopiles are often difficult to apply in some scenarios where the size of the installation space is strictly limited and the instantaneous dynamic changes are severe. Performance in terms of reliability, timeliness, and durability is greatly compromised.

Contents of the invention

In view of this, the object of the present invention is to provide a micro-nano film heat flow sensor based on a metal substrate and a manufacturing method thereof.

To achieve the above object, the present invention provides the following technical solutions:

A micro-nano film heat flow sensor based on a metal substrate, mainly including a metal substrate, 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 Layer II, metal protection sheet, metal transition layer III, metal bonding layer III and epoxy resin.

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

The metal base has a thickness ranging from 50 μm to 800 μm.

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

The metal bonding layer I and the metal bonding layer II have a thickness ranging from 10 nm to 100 nm.

The metal transition layer I and the metal transition layer II have a thickness ranging from 5 μm to 30 μm.

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

The thickness range of the insulating layer I and the insulating layer II is 1 μm˜5 μm.

The surface of the metal sensing layer is electroplated with a metal transition layer II.

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

The metal sensing layer has a thickness ranging from 300nm to 900nm.

The first pole sensing loop includes metal layer I, metal layer II and metal layer III deposited in sequence.

The second pole sensing circuit is deposited on the surface of the first pole sensing circuit, including metal layer IV, metal layer V and metal layer VI deposited in sequence.

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

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

The surface of the insulating layer II is bonded with a metal protection sheet.

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

The surfaces of the insulating layer II and the metal bonding layer III are bonded, so that the metal substrate and the metal protection sheet are bonded.

The metal transition layer III is sputtered with a metal bonding layer III.

Several sets of thermopile circuits are deposited on the high-temperature micro-nano thin-film heat flow sensor based on the metal substrate to realize multi-point detection in a local area. One set of thermopile loops includes a metal sensing layer, a metal transition layer II, a metal bonding layer II, an insulating layer II and a metal protection sheet deposited sequentially.

The micro-nano thin-film heat flow sensor based on the metal substrate can withstand the temperature of 400°C.

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

A method for manufacturing a micro-nano thin-film heat flow sensor based on a metal substrate, mainly comprising the following steps:

Step 1. Select a metal substrate for sensor deposition.

The surface roughness of the metal substrate ranges from 100nm to 400nm.

Step 2, grinding and chemical-mechanical polishing the metal substrate, and depositing a metal transition layer I on the surface of the metal substrate by magnetron sputtering.

Step 3, depositing the metal bonding layer I on the surface of the metal transition layer I by magnetron sputtering process.

Step 4. Coating the insulating layer I on the surface of the metal bonding layer I by a uniform coating and spin coating process, and performing soft drying and curing on a hot plate and an oven respectively.

Step 5. Coating photoresist on the surface of the insulating layer I by a spin-coating process, and pre-baking the metal substrate on a hot plate. Exposure is performed on a photolithography machine using a mask. After exposure, the metal substrate is post-baked on a hot plate. The metal substrate is placed in a developer solution for development, and the sensor plate is obtained after drying.

Step 6. Depositing a metal sensing layer on the surface of the photoresist layer by magnetron sputtering process, the main steps are:

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

Step 6.2. Deposit metal layer IV, metal layer V and metal layer VI in sequence on the surface of the first-pole sensing circuit to form the second-pole sensing circuit, soak in acetone to peel off the photoresist, and then dry.

Step 7. Cut out the metal protection sheet based on the sensor plate.

The metal protection sheet is in the shape of a round crown.

Step 8: Deposit a metal transition layer III on the surface of the metal protection sheet by electroplating, and then deposit a metal bonding layer III on the surface of the metal transition layer III by magnetron sputtering.

Step 9. Coating the insulating layer II on the surface of the metal sensing layer by means of a homogenizing and spin-coating process.

Step 10, using the adhesiveness of the insulating layer II to attach the metal protection sheet to the metal substrate, and expose the pad.

Step 11: Baking and curing the metal substrate bonded with the metal protection sheet, and then removing the insulating layer on the pad surface through a plasma etching process.

Step 12, using conductive silver glue to connect the pad to the compensation wire, and then coating the surface with epoxy resin after baking on a hot plate. The epoxy resin is cured.

The diameter of the compensation wire ranges from 0.2mm to 0.5mm.

It is worth noting that the micro-nano thin-film heat flow sensor is manufactured based on the ultra-clean room MEMS micro-electromechanical processing technology, and the main process links involve photolithography, magnetron sputtering, electron beam evaporation and atomic layer deposition. For more advanced and cutting-edge sensor technologies, the thickness of the working layer is usually only a few hundred nanometers, and the protective layer is usually no more than 1mm. At the same time, the line width and node size of the working layer are on the order of microns. The small size endows it with technical features such as convenient and flexible installation, fast dynamic response, and reliable detection, and it can also reasonably arrange multiple detection points through circuit optimization design in a small local area, which can significantly improve traditional detection components. Due to technical limitations in these aspects, the use of a metal substrate with high hardness, high melting point, and good thermal conductivity as a protective layer can greatly improve the ability and service life of the film sensor to withstand high temperature, high pressure and harsh environments, and provide heat flow detection solutions in various industrial scenarios. Further optimization and further enrichment of detection methods provide an important hardware foundation.

The present invention is based on the classical Seebeck effect and the thermopile principle of multiple sets of K-type thermocouples connected in series, through the MEMS micro-electromechanical processing technology such as uniform glue spin coating, photolithography development, and magnetron sputtering in the ultra-clean room, the melting point and hardness Relatively high metal with good thermal conductivity and electrical conductivity is used as the substrate substrate, and a micro-nano thin-film heat flow sensor with a typical sandwich layer packaging structure that can withstand high temperatures of 400 ° C is produced.

The technical effect of the present invention is unquestionable. The micro-nano film sensor disclosed by the present invention has small size, fast response, and less disturbance to the original thermal field, and can capture the instantaneous dynamic changes of the thermal field in time and accurately, and obtain the transient heat flow , can be flexibly and conveniently installed in a narrow space and closer to the point to be tested for detection, and multiple sets of thermopile circuits can be arranged in one detection area at the same time according to requirements to achieve local multi-point detection; based on relatively high melting point hardness and thermal conductivity The good metal substrate packaging method makes the sensor have good high temperature and high pressure resistance and anti-interference performance, which can effectively guarantee the use effect of the sensor in harsh industrial environments and help to greatly increase its service life.

Other advantages, objects and features of the present invention will be set forth in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the investigation and research below, or can be obtained from Taught in the practice of the present invention. The objects and other advantages of the invention may be realized and attained by the following specification.

Description of drawings

In order to make the purpose of the present invention, technical solutions and advantages clearer, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

Figure 1 is a schematic diagram of the design of the micro-nano film heat flow sensor.

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

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

Fig. 4 is a schematic diagram of the structure of the substrate after the spin-coating of polyimide is completed.

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

Fig. 6 is a schematic diagram of a metal sensing layer deposited by sputtering.

Fig. 7 is a schematic diagram after the deposition of a two-pole sensing circuit is completed.

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

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

FIG. 10 is a schematic structural diagram of a metal sheet required for sensor packaging.

Reference signs: 1-metal substrate, 2-metal transition layer I, 3-metal bonding layer I, 4-insulating layer I, 5-photoresist, 6-metal sensing layer, 601-metal layer I, 602 -Metal layer II, 603-Metal layer III, 604-Metal layer IV, 605-Metal layer V, 606-Metal layer VI, 7-Metal protection sheet, 8-Compensation wire, 9-Pad, 10-Metal transition layer II, 11-metal bonding layer II, 12-insulating layer II, 13-metal transition layer III, 14-metal bonding layer III, 15-epoxy resin, A-cathode, B-anode, T0-lower temperature sensing Contact, T1-upper temperature-sensing contact.

detailed description

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the diagrams provided in the following embodiments are only schematically illustrating the basic concept of the present invention, and the following embodiments and the features in the embodiments can be combined with each other in the case of no conflict.

Wherein, the accompanying drawings are for illustrative purposes only, and represent only schematic diagrams, rather than physical drawings, and should not be construed as limiting the present invention; in order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, Enlargement or reduction does not represent the size of the actual product; for those skilled in the art, it is understandable that certain known structures and their descriptions in the drawings may be omitted.

In the drawings of the embodiments of the present invention, the same or similar symbols correspond to the same or similar components; , "front", "rear" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred devices or components must It has a specific orientation, is constructed and operated in a specific orientation, so the terms describing the positional relationship in the drawings are for illustrative purposes only, and should not be construed as limiting the present invention. For those of ordinary skill in the art, the understanding of the specific meaning of the above terms.

Example 1:

Please refer to Fig. 1 to Fig. 10, a kind of micronano film heat flow sensor based on metal substrate, mainly comprises metal substrate (1), metal transition layer I (2), metal bonding layer I (3), insulating layer I ( 4), photoresist (5), metal sensing layer (6), metal transition layer II (10), metal bonding layer II (11), insulating layer II (12), metal protection sheet (7), metal Transition layer III (13), metal bond layer III (14) and epoxy resin (15).

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

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

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

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

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

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

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

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

The second pole sensing loop is deposited on the surface of the first pole sensing loop, including metal layer IV (604), metal layer V (605) and metal layer VI (606) deposited in sequence. Metal layer I ( 601 ), metal layer III ( 603 ), metal layer IV ( 604 ) and metal layer VI ( 606 ) are bonding layers, which are used to improve the adhesion between the upper layer and the lower layer.

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).

The surface of the insulating layer II (12) is bonded with a metal protection sheet (7).

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).

The insulating layer II (12) is bonded to the surface of the metal bonding layer III (14), so that the metal base (1) and the metal protection sheet (7) are bonded.

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

Several sets of thermopile circuits are deposited on the high-temperature micro-nano thin-film heat flow sensor based on the metal substrate to realize multi-point detection in a local area. One set of thermopile circuits includes 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) deposited in sequence.

The micro-nano thin-film heat flow sensor based on the metal substrate can withstand the temperature of 400°C.

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

Example 2:

A micro-nano thin-film heat flow sensor based on a metal substrate, the main structure is shown in Example 1, wherein,

The metal base (1) has a thickness of 50 μm;

The thickness of metal transition layer I (2) and metal transition layer II (10) is 5 μm;

The thickness of metal bonding layer I (3), metal bonding layer II (11) is 10nm;

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

The metal sensing layer (6) has a thickness of 300nm.

Example 3:

A micro-nano thin-film heat flow sensor based on a metal substrate, the main structure is shown in Example 1, wherein,

The metal base (1) has a thickness of 800 μm;

The thickness of metal transition layer I (2) and metal transition layer II (10) is 30 μm;

The thickness of metal bonding layer I (3), metal bonding layer II (11) is 100nm;

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

The metal sensing layer (6) has a thickness of 900nm.

Example 4:

A micro-nano thin-film heat flow sensor based on a metal substrate, the main structure is shown in Example 1, wherein,

The metal base (1) has a thickness of 425 μm;

The thickness of metal transition layer I (2) and metal transition layer II (10) is 17.5 μm;

The thickness of metal bonding layer I (3), metal bonding layer II (11) is 55nm;

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

The metal sensing layer (6) has a thickness of 600nm.

Example 5:

A micro-nano film heat flow sensor based on a metal substrate, mainly as follows:

Using metal as the substrate substrate of the sensor, the transition layer, bonding layer, insulating layer, sensing layer and protective layer are deposited layer by layer through electroplating, spin coating, photolithography, magnetron sputtering and other process steps to form a typical The sandwich layer structure; the design of the sensing layer is based on the thermopile principle, that is, multiple K-type thermocouples are connected in series, and two different nickel-based alloys are used as the bipolar materials that constitute the thermocouple circuit. Signal acquisition and reading to obtain the heat flow value of the detection point; multiple sets of thermopile circuits can be deposited on the sensing layer of the same substrate at the same time to achieve multi-point detection in a narrow local area, with high spatial resolution, and even one If the detection point is damaged, the remaining detection points can still work normally, and the detection redundancy is good; the film thickness of the sensor is only hundreds of nanometers, the line width and thermal junction size are small, the mass and heat capacity are small, and the rapid The change response is rapid, and its response time can reach the microsecond level, and it is less destructive to the real thermal field interference at the detection point; A good polymer insulating material is used as an insulating layer, which can reliably realize heat flow detection in an environment of 400°C; a layer of metal similar to it and having good thermal conductivity and strength is electroplated on the substrate as a transition layer; the alloy material of the sensing layer A layer of metal is sputtered on the top and bottom as the bonding layer to effectively enhance the bonding between the sensing layer and the insulating layer and prevent delamination; the sensor pad uses a conductive bonding material that can withstand high temperatures as a wire The connection material can ensure the reliability and stability of the sensor in long-term high-temperature environment.

Metals with good electrical and thermal conductivity, relatively high melting point and hardness are used as the substrate for the sensor.

The sensor is a typical sandwich layer structure, including transition layer, bonding layer, insulating layer, sensor and protective layer, which are sequentially deposited layer by layer through processes such as electroplating, spin coating, photolithography and magnetron sputtering. Wherein, the thickness of the transition layer is 5 μm-30 μm, the thickness of the bonding layer is 10 nm-100 nm, the thickness of the insulating layer is 1 μm-5 μm, and the thickness of the sensing layer is 300 nm-900 nm.

The design of the sensor is based on the thermopile principle of multiple sets of K-type thermocouples in series, and NiCr-NiAlMnSi, NiCr-NiAl, NiCr-NiSi alloys are used as the two-pole materials forming the thermocouple circuit.

Multiple sets of thermopile circuits are simultaneously deposited on the sensing layer of the same substrate to realize multi-point detection in a narrow local area.

The film thickness of the sensor is as thin as hundreds of nanometers, the line width and thermal junction size are small, the mass and heat capacity are small, and it can quickly reflect the transient changes of the thermal field, and its response time can reach the microsecond level, and it does not interfere with the real thermal field of the detection point Less destructive.

The sensor uses polyimide with good thermal stability and mechanical properties as the insulating layer, which can reliably realize heat flow detection in an environment of 400 °C.

A layer of metal titanium is sputtered on the surface of the transition layer as a bonding layer to effectively enhance the bonding between the metal substrate and the insulating layer.

A layer of metal titanium is sputtered on the top and bottom of the sensing layer of the sensor as a bonding layer to effectively enhance the bonding between the sensing layer and the insulating layer.

The sensor pad uses two-component conductive silver glue as the wire connection material to ensure the reliability and stability of the sensor in long-term high-temperature environments.

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

Embodiment 6:

A method for manufacturing a micro-nano thin-film heat flow sensor based on a metal substrate, mainly comprising the following steps:

1) Select the metal substrate (1) for sensor deposition.

The surface roughness of the metal substrate (1) ranges from 100nm to 400nm.

2) Grinding and chemical-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.

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

4) Coating the insulating layer I(4) on the surface of the metal bonding layer I(3) by a spin-coating process, and performing soft drying and curing on a hot plate and an oven, respectively.

5) Coating a photoresist (5) on the surface of the insulating layer I (4) by a spin-coating process, and pre-baking the metal substrate (1) on a hot plate. Exposure is performed on a photolithography machine using a mask. After exposure, the metal substrate 1 is post-baked on a hot plate. The metal substrate (1) is placed in a developing solution for development, and the sensor plate is obtained after drying.

6) Depositing a metal sensing layer (6) on the surface of the photoresist layer by a magnetron sputtering process, the main steps are:

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

6.2) Deposit metal layer IV (604), metal layer V (605) and metal layer VI (606) sequentially on the surface of the first-pole sensing circuit to form the second-pole sensing circuit, then place it in acetone for soaking and stripping Carving (5) and then drying.

7) Based on the sensor plate, cut out the metal protection sheet (7).

The metal protection sheet (7) is in the shape of a round crown.

8) Depositing a metal transition layer III (13) on the surface of the metal protection sheet (7) by electroplating, and then depositing a metal bonding layer III (14) on the surface of the metal transition layer III (13) by magnetron sputtering.

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

10) Using the adhesiveness of the insulating layer II, attach the metal protection sheet (7) to the metal substrate (1), and expose the pad (9).

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

12) Connect the pad (9) to the compensation wire (8) with conductive silver glue, and then coat the surface with epoxy resin after baking on a hot plate. The epoxy resin (15) is cured.

The diameter of the compensation wire (8) ranges from 0.2 mm to 0.5 mm.

Embodiment 7:

A method for manufacturing a micro-nano film heat flow sensor based on a metal substrate, mainly as follows:

1) According to the requirements of heat flow detection, design and manufacture micro-nano film heat flow sensors, including the shape, size and quantity of the sensors, as shown in Figure 1.

2) A metal with a diameter of 4” and a thickness of 800 μm is used as the substrate substrate for sensor deposition. After the copper sheet is polished and polished, a metal transition layer with a thickness of 5 μm to 30 μm is deposited on the surface, as shown in Figure 2.

3) Deposit a layer of metal titanium with a thickness of 10nm-100nm on the surface of the transition layer by a magnetron sputtering process, as shown in FIG. 3 .

4) Coat a layer of polyimide, an organic polymer material with a thickness of 1 μm to 5 μm, on the surface of the titanium layer through the spin coating process, and perform soft drying and curing on a hot plate and an oven, as shown in Figure 4 .

5) Coat a layer of photoresist with a thickness of 1 μm to 5 μm on the surface of the insulating layer through a uniform coating and spin coating process, and perform pre-baking on a hot plate, and then use a mask to expose on a photolithography machine, and then place it Post-baking on a hot plate, and then placed in a developer solution for development, after cleaning and drying, a plate of the shape and size of the sensor will be formed, as shown in Figure 5.

6) Three layers of metal are sequentially deposited on the surface of the photoresist layer by magnetron sputtering, which are metal titanium with a thickness of 10nm to 100nm, nickel-based alloy with a thickness of 300nm to 900nm, and titanium metal with a thickness of 10nm to 100nm to form the first One pole sensing loop.

7) Repeat the above process steps, deposit metal titanium, another pole nickel-based alloy, and metal titanium in sequence to form the second pole sensing circuit, place it in acetone for soaking and peel off the photoresist, and then dry it, as shown in Figure 6 with Figure 7.

8) According to the size characteristics of the sensor, the metal sheet of the protective layer in the shape of a circular crown is cut, and the transition layer and the bonding layer are sequentially deposited by the electroplating process and the magnetron sputtering process respectively.

9) Apply a layer of polyimide with a thickness of 1 μm to 5 μm on the finished sensing layer through the spin-coating process, and use its adhesiveness to bond the copper sheet processed in the previous step to the substrate. The pads are just exposed, and then baked and solidified to form a sandwich layer packaging structure. Finally, the insulating layer on the surface of the pads is removed by plasma etching to expose the pads for wiring, as shown in Figure 8.

10) Use conductive silver glue to connect compensation wires to all pads on the sensing layer, apply a layer of epoxy resin after baking and curing on a hot plate, and then complete the entire sensor after 10 hours to 36 hours of aging curing. production, which detects heat flow by collecting potential signals, and the sensing layer is its core working layer, as shown in Figure 9.

Embodiment 8:

A method for manufacturing a micro-nano film heat flow sensor based on a metal substrate, mainly as follows:

1) Firstly, according to the requirements of heat flow detection, a micro-nano film heat flow sensor is designed, as shown in Figure 1, including the shape, size and quantity of the sensor. The design of the sensor is based on the thermoelectric principle of the Seebeck effect and the thermopile principle of multiple sets of K-type thermocouples in series, that is, two different conductors are used as anode and cathode respectively, and their two ends are closely connected to each other to form a closed loop. When the temperature of the two junctions is not equal, T1>T0, an electromotive force will be generated in the circuit, thereby forming a thermal current; multiple sets of thermocouples with the same physical properties are connected in series to form a thermopile, and the temperature difference between two points in the heat transfer direction It will be enlarged, and the magnification depends on the number of series groups. A key indicator of the thermopile is sensitivity, that is, the thermoelectric potential output per unit heat flow, and its value depends on the thermal conductivity of the substrate material, the number of thermocouples in series and the distance between the temperature-sensing junctions at the upper and lower ends, and satisfies, good The design must ensure sufficient sensitivity. The sensor adopts a thermopile composed of multiple sets of K-type thermocouples connected in series, and uses a K-type thermocouple alloy as the sensing layer. Multiple sets of sensors are arranged on the substrate according to requirements, and each set of sensors can be arranged with multiple pairs of thermocouple thermopile circuits. The design of the circuit wiring should be as symmetrical and beautiful as possible and easy to cut and process. At the same time, the sensor should also be considered when considering the plane size of the sensor. The success rate of production, that is, the line width of a single electrode and the distance between each pair of electrodes should not be too small. In addition, in order to reduce the difficulty of wire connection and ensure the insulation between each pair of pads, the single square pad The side length dimension and the distance between each pair of pads should also not be too small.

2) Use a metal copper sheet with a diameter of 4” and a thickness of 800 μm as the substrate for sensor deposition. The melting point of copper is about 1083°C, the boiling point is about 2567°C, and the Vickers hardness is about 350MPa. It has good ductility and thermal conductivity. performance, and it is a heavy metal that is not very active. Considering the thermal conductivity and material strength, it is more appropriate to choose it as a protective layer. After the copper sheet is polished and polished, it should ensure that the surface roughness is low, the surface is smooth, There are no obvious defects such as scratches and pits, and pretreatments such as substrate cleaning and deposition of transition layers are carried out.

In order to enhance the bonding between the metal substrate substrate and the subsequent insulating layer, it is necessary to deposit a layer of titanium metal with a thickness of 10nm to 100nm on the surface of the transition layer by magnetron sputtering as a bonding layer, as shown in Figure 3, if The surface of the substrate is relatively rough, and the deposition thickness can be appropriately increased. The so-called sputtering is the use of plasma with kinetic energy above tens of electron volts to bombard the surface of a solid target, and the atoms near the surface obtain part of the energy carried by the incident particles. When it is enough to overcome the binding energy, these atoms will break away from the solid and become into a vacuum chamber and subsequently deposited onto a substrate. The specific sputtering process parameters are: sputtering power 200W~600W, sputtering rate 10nm/min~20nm/min, sputtering time 2min~6min, of course, the parameters may be adjusted for different equipment platforms.

3) Next, it is necessary to make an insulating layer, that is, to coat a layer of polyimide on the surface of the titanium layer through a uniform coating process. Temperature range -200℃～300℃, no obvious melting point, it can be said to be one of the polymers with the best thermal stability, and has excellent mechanical properties and heat aging resistance, its tensile strength is about 170MPa～400MPa, elastic modulus It is about 3GPa～4GPa, and after 200℃ and 1500 hours of aging treatment, the tensile strength decreases very little. It has high insulation performance, the dielectric constant is usually around 3.4, and the dielectric loss is only 0.004～0.007. It belongs to F to H grade. Insulation Materials. First, spin coating is performed on the substrate using a coater. Then, soft bake on a hot plate. Next, it is baked and cured in an oven. Based on the comprehensive consideration of good thermal conductivity and insulation protection, it is more appropriate to control the thickness of the insulating layer at 0.5 μm to 5 μm after baking and curing.

4) In order to make the designed sensor plate to carry out the sputtering deposition of the metal sensing layer in the next step, it is necessary to coat a layer of photoresist with a thickness of 1 μm to 5 μm on the surface of the insulating layer through a spin-coating process. . Then, a pre-bake is performed on a hot plate to remove solvent from the photoresist and enhance adhesion. Next, the pre-baked substrate is placed on a photolithography machine for exposure. After the exposure, the substrate is placed on a hot plate for post-baking to stimulate the acid produced by the PAG photosensitive acid generator of the chemically amplified photoresist to react with the protective group on the photoresist and remove the group to make it Can be dissolved in the developer solution, while reducing the standing wave effect. Subsequently, the post-baked substrate was placed in a developer for development. After the development was completed, it was cleaned with deionized water and dried with nitrogen to finally form a plate of the shape and size of the sensor, as shown in Figure 5.

5) Next, start to make the core metal sensing layer. First, sputter a layer of metal titanium with a thickness of 10nm-100nm according to the process method described in step 3. Then deposit a layer of nickel-based alloy with a thickness of 300-900nm by magnetron sputtering. The specific sputtering process parameters are: sputtering power 200W-600W, sputtering rate 10nm/min-20nm/min, sputtering time 30min-80min , of course, the parameters may be adjusted for different device platforms. Then, sputter a layer of metal titanium with a thickness of 10-100 nm according to the process method described in the third step. After the deposition is completed, the deposition of the first pole sensing circuit is completed, as shown in FIG. 6 .

6) Repeat the above process steps, and then sputter deposit a layer of titanium metal with a thickness of 10nm-100nm. Then sputter deposit another layer of nickel-based alloy with a thickness of 300nm~900nm. The specific sputtering process parameters are: sputtering power 200W~600W, sputtering rate 10nm/min~20nm/min, sputtering time 30min~80min , of course, the parameters may be adjusted for different device platforms. Then a layer of metal titanium with a thickness of 10nm-100nm is deposited by sputtering. After the deposition is completed, the deposition of the second electrode sensing circuit is completed, the photoresist is peeled off after soaking, and then cleaned and dried, as shown in FIG. 7 . So far, the production of the core sensing layer has been completed.

7) In order to prevent the thin-film sensor from being worn and eroded in harsh environments to enhance its durability, it needs to be packaged for protection. First, cut the copper sheet in the shape of a round crown according to the size characteristics of the sensor, and then use the electroplating process and magnetron sputtering process to deposit a layer of transition layer metal with a thickness of 5 μm to 30 μm and a layer of transition layer metal with a thickness of 10nm. The 100nm bonding layer metal titanium is ready for the next step of packaging, as shown in Figure 10.

8) Next, first coat the finished sensing layer with a layer of polyimide with a thickness of 1-5 μm through the spin-coating process, and use its adhesiveness to paste the copper sheet prepared in the previous step. bonded to the substrate, just to expose the pads, and then bake and solidify in an oven to form a sandwich layer package structure, and finally remove the insulating layer on the surface of the pads by plasma etching to expose the solder for the leads. plate.

9) The next step is the final connection step. First, use conductive silver glue to connect compensation wires with a diameter of 0.2mm to 0.5mm to all pads on the sensing layer, and then after baking on a hot plate, apply a layer of epoxy resin to cover it to reduce the external force on the connection wires and soldering wires. Influenced by the bonding part of the disk to prevent the disconnection of the connection, after 10 hours to 36 hours of aging curing, the production of the entire sensor is completed. It detects the heat flow by collecting potential signals, and the sensing layer is its core working layer. See Figure 9 shows.

The metal substrate-based micro-nano film sensor proposed by the present invention has small size, fast response, and less interference to the original thermal field. Installed in a narrow space and closer to the point to be tested for detection, multiple sets of thermopile circuits can be arranged in one detection area at the same time according to requirements to achieve local multi-point detection; based on metal copper lining with relatively high melting point hardness and good thermal and electrical conductivity The sandwich layer packaging structure at the bottom makes the sensor have good high temperature and high pressure resistance and anti-interference performance, which can effectively avoid wear and erosion, can effectively guarantee the use effect of thin film sensors in harsh industrial environments, and help to greatly improve Its durability and service life. The invention can significantly improve the technical limitations and drawbacks of traditional heat flow detection components in terms of space size, dynamic response and packaging protection, etc., and provides an important hardware foundation and technical means for the optimization and innovation of traditional heat flow detection methods. application in the detection field.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements, without departing from the spirit and scope of the technical solution, should be included in the scope of the claims of the present invention.

Claims (8)

1. A micro-nano film heat flow sensor based on a metal substrate, characterized in that: mainly comprising a metal base (1), a metal transition layer 1 (2), a metal bonding layer 1 (3), an insulating layer 1 (4) , metal sensing layer (6), metal transition layer II (10), metal bonding layer II (11), insulating layer II (12), metal protection sheet (7), metal transition layer III (13) and epoxy Resin(15); The metal base (1) is a substrate, and the surface is electroplated with a metal transition layer I (2); The surface of the metal transition layer I(2) is sputtered with a metal bonding layer I(3); 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); The surface of the metal sensing layer (6) is electroplated with a metal transition layer II (10); The metal sensing layer (6) includes a first pole sensing loop and a second pole sensing loop; The first pole sensing circuit includes metal layer I (601), metal layer II (602) and metal layer III (603) deposited in sequence; The second pole sensing circuit is deposited on the surface of the first pole sensing circuit, including metal layer IV (604), metal layer V (605) and metal layer VI (606) deposited sequentially; The surface of the metal transition layer II (10) is sputtered with a metal bonding layer II (11); The surface of the metal bonding layer II (11) is coated with an insulating layer II (12); The surface of the insulating layer II (12) is bonded with a metal protection sheet (7); The lower surface of the metal protection sheet (7) opposite to the insulating layer II (12) is electroplated with a metal transition layer III (13), and the other surface is coated with epoxy resin (15). 2. a kind of micro-nano film heat flow sensor based on metal substrate according to claim 1, is characterized in that, the surface sputtering of described metal transition layer III (13) has metal bonding layer III (14), so The surface of the insulating layer II (12) and the metal bonding layer III (14) are bonded, so that the metal substrate (1) and the metal protection sheet (7) are bonded. 3. A kind of micro-nano film heat flow sensor based on metal substrate according to claim 1, characterized in that: The metal substrate (1) has a thickness ranging from 50 μm to 800 μm; The thickness of the metal transition layer I(2) and metal transition layer II(10) ranges from 5 μm to 30 μm; The thickness range of the metal bonding layer I (3) and the metal bonding layer II (11) is 10 nm to 100 nm; The thickness range of the insulating layer I (4) and the insulating layer II (12) is 1 μm to 5 μm; The metal sensing layer (6) has a thickness ranging from 300nm to 900nm. 4. A method for making a micro-nano film heat flow sensor based on a metal substrate, characterized in that it mainly comprises the following steps: Step 1, selecting the metal base (1) for sensor deposition as the substrate; Step 2, grinding and chemical-mechanical polishing the metal substrate (1), and depositing a metal transition layer I (2) on the surface of the metal substrate (1) by a magnetron sputtering process; Step 3, depositing a metal bonding layer I (3) on the surface of the metal transition layer I (2) by a magnetron sputtering process; Step 4, coating the insulating layer I (4) on the surface of the metal bonding layer I (3) by a spin-coating process, and performing soft drying and curing respectively on a hot plate and an oven; Step 5. Coating photoresist (5) on the surface of insulating layer I (4) by means of uniform glue spin coating process, and pre-baking the metal substrate (1) on a hot plate; using a mask plate on a photolithography machine Exposure; after exposure, post-baking the metal substrate (1) on a hot plate; placing the metal substrate (1) in a developing solution for development, and obtaining a sensor plate after drying; Step 6, depositing a metal sensing layer (6) on the surface of the photoresist layer by a magnetron sputtering process; Step 7, based on the sensor plate, cut out the metal protection sheet (7); Step 8. Deposit a metal transition layer III (13) on one surface of the metal protection sheet (7) by electroplating, and then deposit a metal bonding layer III (14) on the surface of the metal transition layer III (13) by magnetron sputtering ; Step 9, coating the insulating layer II (12) on the surface of the metal sensing layer (6) by a homogeneous spin coating process; Step 10, using the adhesiveness of the insulating layer II (12) to attach the surface of the metal protection sheet (7) to deposit the metal transition layer III (13) and the metal bonding layer III (14) on the metal substrate (1) , and exposed pad (9); Step 11, baking and curing the metal substrate (1) attached with the metal protection sheet (7), and then removing the insulating layer on the surface of the pad (9) through a plasma etching process; Step 12, using conductive silver glue to connect the welding pad (9) and the compensation wire (8), and then after baking on a hot plate, coat the epoxy resin (15) on the surface; and cure the epoxy resin (15). 5. the manufacture method of the micro-nano film heat flow sensor based on metal substrate according to claim 4, is characterized in that, described magnetron sputtering process deposits metal sensing layer (6) on photoresist layer surface, The main steps are: Step 6.1, sequentially depositing metal layer I (601), metal layer II (602) and metal layer III (603) on the surface of the photoresist layer to form a first pole sensing circuit; Step 6.2. Deposit metal layer IV (604), metal layer V (605) and metal layer VI (606) sequentially on the surface of the first-pole sensing circuit to form the second-pole sensing circuit, then place it in acetone for soaking and stripping The photoresist (5) is then dried. 6 . The method for manufacturing a micro-nano thin film heat flow sensor based on a metal substrate according to claim 4 , characterized in that the surface roughness of the metal substrate ( 1 ) ranges from 100 nm to 400 nm. 7. The manufacturing method of the micro-nano film heat flow sensor based on the metal substrate according to claim 4, characterized in that, the metal protection sheet (7) is in the shape of a circular crown. 8 . The method for manufacturing a micro-nano thin film heat flow sensor based on a metal substrate according to claim 4 , wherein the diameter of the compensation wire ( 8 ) ranges from 0.2mm to 0.5mm.

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