A micro-heater and a manufacturing method thereof

Abstract

A microheater and its fabrication method are disclosed, comprising: a flexible circuit board, a substrate, a heating element, and a micro-temperature sensor. The heating element is configured with a filled curve structure, and the micro-temperature sensor extends from the center of the filled curve structure of the heating element to its periphery, adapting to the filled curve structure. The flexible circuit board includes pads, the heating element includes a first electrode, and the micro-temperature sensor includes a second electrode. The pads are electrically connected to the first and second electrodes, respectively. This invention achieves uniform temperature distribution by increasing the order of the wiring within a limited area. The micro-temperature sensor integrated inside the heating element accurately reflects the surface temperature of the heating element based on the resistance temperature coefficient (RTC) effect, improving the accuracy of temperature detection. This invention has a simple structure, provides uniform temperature in the microheater, and the integrated micro-temperature sensor exhibits high temperature measurement accuracy, meeting the high requirements of polymerase chain reaction (PCR) chips and facilitating widespread adoption.

Description

Technical Field

[0001] This invention relates to the field of electrothermal technology, and more specifically to a micro heater and its manufacturing method. Background Technology

[0002] Polymerase chain reaction (PCR) chips are miniature systems used to rapidly amplify DNA. Compared to PCR amplification instruments, they offer advantages such as low cost, integrability, and portability, and are currently widely used in PCR applications. In PCR applications, enzyme activity directly determines amplification efficiency, and enzyme activity is closely related to temperature. Therefore, uniform and accurate temperature is a key factor in improving PCR efficiency. PCR chips provide the appropriate temperature for polymerase chain reactions through microheaters integrated within them. Thus, the temperature performance of the microheaters directly affects PCR efficiency, and improving microheater performance has become a current research focus. Microheaters consist of a substrate and microwire structures fabricated on the substrate. When the substrate material is the same, temperature uniformity is mainly affected by the shape of the microheater. In recent years, various shapes of microheaters have been proposed to improve temperature uniformity. Furthermore, instruments such as resistance thermometers and infrared thermometers are used to measure the surface temperature of the microheaters in real time, leading to the increasingly widespread application of microheaters in PCR and biomedical fields.

[0003] However, the uniformity of the known microheaters still has room for optimization. In terms of measuring the surface temperature of microheaters, methods such as infrared thermometers have poor measurement accuracy and cannot accurately reflect the temperature in real time, which brings great difficulties to temperature control. Summary of the Invention

[0004] (I) Purpose of the Invention

[0005] The purpose of this invention is to provide a microheater and its manufacturing method that can improve thermal uniformity and temperature measurement accuracy.

[0006] (II) Technical Solution

[0007] To address the aforementioned problems, the present invention provides a micro heater, comprising: a flexible circuit board 1, a substrate 2, a heating element 3, and a micro temperature sensor 4. The substrate 2 is disposed on the flexible circuit board 1, and the heating element 3 is disposed on the substrate 2. The heating element 3 is configured with a filled curve structure, and the micro temperature sensor 4 extends from the center of the filled curve structure of the heating element 3 to the periphery of the filled curve structure of the heating element 3 and is adapted to the filled curve structure of the heating element 3. The flexible circuit board 1 is electrically connected to the heating element 3 and the micro temperature sensor 4 respectively.

[0008] In one aspect of the invention, preferably, the filling curve structure is formed by a metal material with a width of W1 and a thickness of H1 extending along a predetermined curve path, the predetermined curve path including at least one of a Peano space filling curve, a triangular filling curve, and a serpentine filling curve; the micro-temperature sensor 4 is disposed along the curve path and located in the gap of the curve path.

[0009] In one aspect, preferably, the invention further includes a PID control system electrically connected to the flexible circuit board 1. The PID control system regulates the temperature rise rate in real time by adjusting the duty cycle of the voltage across the heating element 3, including:

[0010]

[0011] Where: u(k) represents the output quantity; e(k) represents the current error value, which is equal to the difference between the target value and the current output quantity; e(k-1) represents the previous error value, K P K represents the proportionality coefficient. I Represents the integration time constant, corresponding to parameters I and K. D This represents the differential coefficient.

[0012] In one aspect of the present invention, preferably, there is a gap between the heating element 3 and the micro temperature sensor 4, the gap being 40-50 μm.

[0013] In one aspect of the present invention, preferably, in the filled curve structure formed by the extension of the metal material, the distance between adjacent metal materials is d1, and the width W1, thickness H1, and distance d1 satisfy the following formula:

[0014] W1≤d1

[0015] H1 < W1

[0016] W1+d1≤400μm.

[0017] In one aspect of the present invention, preferably, the micro-temperature sensor 4 has a width of W2, a length of L2, and a thickness of H2, a gap of d2 between the heating component 3 and the micro-temperature sensor 4, and a distance of d3 between the wires of adjacent micro-temperature sensors 4, satisfying the following formula:

[0018] H2 = H1

[0019] L2≥1 / 12L1

[0020] W2≤(d1-2d2-d3) / 2.

[0021] In one aspect of the present invention, preferably, the flexible circuit board 1 includes a pad 6, the heating component 3 includes a first electrode 3-1, the micro-temperature sensor 4 includes a second electrode 4-1, and the pad 6 is electrically connected to the first electrode 3-1 and the second electrode 4-1 respectively.

[0022] In one aspect of the present invention, preferably, it further includes conductive adhesive 5, wherein the pads 6 are electrically connected to the first electrode 3-1 and the second electrode 4-1 respectively through the conductive adhesive 5.

[0023] In one aspect of the present invention, preferably, a method for fabricating a microheater, used to fabricate a heating element 3 and a micro-temperature sensor 4 as described in any one of the above, comprising:

[0024] Fabricate a mask plate that includes a heating element 3 filling curve structure and a micro temperature sensor 4 structure;

[0025] Photoresist is spin-coated onto substrate 2, and the mask is placed on substrate 2 coated with photoresist for exposure.

[0026] After the photoresist-coated substrate 2 is exposed and developed, the mask is removed, and metal is sputtered onto the surface of the developed substrate 2 using a magnetron sputtering process.

[0027] The unexposed photoresist on the developed substrate 2 was removed using a stripping process.

[0028] Insulation is achieved by spin-coating an insulating medium onto the metal surface of substrate 2 after a peeling process using a spin coater.

[0029] A substrate 2 with a heating element 3 and a micro temperature sensor 4 is obtained.

[0030] In one aspect, preferably, the invention further includes:

[0031] A substrate 2 with a heating element 3 and a micro temperature sensor 4 is disposed on a flexible circuit board 1;

[0032] The conductive adhesive 5 is used to connect the pads 6 on the flexible circuit board 1 to the first electrode 3-1 of the heating component 3 and the second electrode 4-1 of the micro temperature sensor 4, respectively.

[0033] The PID control system is electrically connected to the flexible circuit board 1.

[0034] (III) Beneficial Effects

[0035] The above-described technical solution of the present invention has the following beneficial technical effects:

[0036] This invention addresses this issue by configuring the heating element as a filled curve structure. By increasing the order of the wiring within a limited area, it achieves uniform temperature distribution. Furthermore, by extending the micro-temperature sensor from the center of the filled curve structure outwards and adapting it to the structure, it enables more accurate temperature measurement. Applying a voltage across the electrodes of the heating element causes a temperature field to be generated due to Joule heating when current flows through. The integrated micro-temperature sensor, based on the resistance temperature coefficient (RTC) effect, accurately reflects the surface temperature of the heating element, thus improving temperature detection accuracy. This invention features a simple structure, uniform temperature distribution in the micro-heater, and high accuracy of the integrated micro-temperature sensor, meeting the high requirements of polymerase chain reaction (PCR) chips and facilitating widespread adoption. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the present invention;

[0038] Figure 2 This is a structural diagram of a heating element and a micro-temperature sensor according to an embodiment of the present invention;

[0039] Figure 3 This is a structural diagram of a heating component according to another embodiment of the present invention;

[0040] Figure 4 This is a structural diagram of a heating component according to another embodiment of the present invention;

[0041] Figure 5 This is a flowchart of a method for preparing a heating component according to an embodiment of the present invention;

[0042] Figure 6 This is a demonstration diagram of a heating component preparation method according to an embodiment of the present invention;

[0043] Figure label:

[0044] 1: Flexible circuit board; 2: Substrate; 3: Heating component; 4: Micro temperature sensor; 5: Conductive adhesive; 6: Solder pad; 3-1: First electrode; 4-1: Second electrode. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0046] The accompanying drawings illustrate a layer structure according to an embodiment of the present invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0047] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0048] In the description of this invention, it should be noted that the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] Example 1

[0051] A micro heater, Figure 1 A schematic diagram of the overall structure of an embodiment of the present invention is shown, as follows. Figure 1As shown, the system includes: a flexible circuit board 1, a substrate 2, a heating element 3, and a micro-temperature sensor 4. The specific shape of the flexible circuit board 1 is not limited here; it can be a regular shape such as a circle, rectangle, or triangle, or an irregular shape. Optionally, in this embodiment, the flexible circuit board 1 is rectangular, and the substrate 2 is disposed on the flexible circuit board 1. It is not limited whether the substrate 2 is directly disposed on the flexible circuit board 1; a heat insulation layer can be placed between them. Optionally, in this embodiment, the substrate 2 is directly disposed on the flexible circuit board 1. The connection method between the substrate 2 and the flexible circuit board 1 is also not limited here; it can be adhesive, snap-fit, etc. The specific structure and material of the substrate 2 are not limited here; the material of the substrate 2 can be a silicon wafer, glass sheet, ceramic, or PI film, etc. Optionally, in this embodiment, the material of the substrate 2 is a silicon wafer. The size and structural relationship between the substrate 2 and the flexible circuit board 1 are also not limited here; optionally, the structure of the substrate 2 is the same shape as the flexible circuit board 1 but different in size, or the structure of the substrate 2 is the same as the flexible circuit board 1. The structure has different shapes and sizes. Optionally, the size of the base 2 is smaller than that of the flexible circuit board 1, or the length of the base 2 is the same as that of the flexible circuit board 1, but the width of the base 2 is different from that of the flexible circuit board 1. Optionally, in this embodiment, the length and width of the base 2 are smaller than those of the flexible circuit board 1, leaving space for connection. The heating component 3 is disposed on the base 2. The specific material and structure of the heating component 3 are not limited here. Optionally, the material of the heating component 3 is a metal material. Further, the material of the heating component 3 can be a single metal material or a composite metal material, such as gold, platinum, copper, titanium, nickel-chromium alloy, etc. Optionally, in this embodiment, the material of the heating component 3 is gold. The specific structure of the heating component 3 is not limited here. Optionally, the heating component 3 is set as a filled curve structure. A filled curve is a curve used to draw in three-dimensional space. A filled curve is a curve that fills the entire space by repeatedly using the same curve. By increasing the order and dense wiring in a limited area, the temperature distribution is made uniform. The curve is represented as a sequence of points, which can be obtained by sampling. The basic principle of a fill curve is to draw a continuous curve in three-dimensional space that passes through specified points, lines, polygons, and other graphic objects while maintaining the relationships between them. Fill curves can be used to draw various shapes, such as circles, ellipses, rectangles, and triangles. The implementation of fill curves is typically based on a mesh structure, where each node is represented as a point, and each edge is determined by a set of base points.The specific content of the filling curve structure is not limited here. The micro-temperature sensor 4 extends from the center of the filling curve structure of the heating element 3 to the periphery of the filling curve structure of the heating element 3. It is not limited whether the micro-temperature sensor 4 starts from the exact center of the filling curve structure of the heating element 3. Optionally, it can be located near the center, at the exact center, or it can circle around the center and then extend outward. The length of the micro-temperature sensor is not limited here, nor is the material of the micro-temperature sensor 4 limited. Optionally, the micro-temperature sensor 4 can be the same metal material as the heating element 3, or it can be a different metal material. Furthermore, the micro-temperature sensor 4 can be a single metal material or a composite material. Optionally, the material of the micro-temperature sensor 4 can be gold, platinum, copper, titanium, or nickel-chromium alloy, etc. Optionally, in this embodiment, the material of the micro-temperature sensor 4 is gold. The micro-temperature sensor 4 is adapted to the filling curve structure of the heating component 3. By extending the micro-temperature sensor from the center of the filling curve structure of the heating component to the periphery of the filling curve structure of the heating component and adapting it to the filling curve structure of the heating component, the temperature of the heating component can be measured more accurately. The flexible circuit board 1 is electrically connected to the heating component 3 and the micro-temperature sensor 4 respectively.

[0052] This embodiment, by setting the heating element as a filled curve structure, can increase the order of the wiring within a limited area to achieve uniform temperature distribution. By extending the micro-temperature sensor from the center of the filled curve structure outwards and adapting it to the structure, the temperature of the heating element can be measured more accurately. Applying a voltage across the electrodes of the heating element causes a temperature field to be generated due to Joule heating when current flows through it. The micro-temperature sensor integrated inside the heating element, based on the resistance temperature coefficient (RTC) effect, can accurately reflect the surface temperature of the heating element, improving the accuracy of temperature detection. This embodiment has a simple structure, uniform temperature of the micro-heater, and high accuracy of the integrated micro-temperature sensor, meeting the high requirements of polymerase chain reaction (PCR) chips and facilitating widespread adoption.

[0053] In one embodiment of the present invention, the filled curve structure is further formed by a metal material with a width of W1 and a thickness of H1 extending along a predetermined curved path. Figure 2 A structural diagram of a heating element and a micro-temperature sensor according to an embodiment of the present invention is shown; Figure 3 This is a structural diagram of a heating component according to another embodiment of the present invention; Figure 4This is a structural diagram of a heating component according to another embodiment of the present invention; the predetermined curved path includes at least one of a Peano space-filled curve, a triangle-filled curve, and a serpentine-filled curve; the micro-temperature sensor 4 is disposed along the curved path and located in the gap of the curved path. The structure of the Peano space-filled curve is as follows: Figure 3 As shown, the Peano filling curve is a commonly used curve in Euclidean geometry, also known as a natural curve. It is a curve that connects points, lines, and surfaces in two-dimensional or three-dimensional Euclidean space. In two-dimensional space, the Peano filling curve connects all points, called Peano points; in three-dimensional space, it connects all surfaces, called Peano surfaces. The characteristic of the Peano filling curve is that it can connect any two points in Euclidean space, ensuring that at least two points are connected. This means that in Euclidean geometry, we can find a unique curve that connects all points in space without intersecting other curves or surfaces, such as... Figure 3 As shown, the Peano space-filled curve structure is square. Optional, such as... Figure 4 As shown, the heating component 3 can also be a triangular filled curve structure, optionally, such as... Figure 2 As shown, the heating component 3 can also be a flow snake filled curve structure with snowflake-shaped edges. Further, optionally, the heating component 3 can be one of a Peano space filled curve structure, a triangular filled curve structure, or a flow snake filled curve structure, or a combination of two or three of the Peano space filled curve structure, triangular filled curve structure, or flow snake filled curve structure. By increasing the order and making the wiring denser within a limited area, the temperature distribution becomes uniform, making it possible to manufacture high-performance polymerase chain reaction (PCR) chips.

[0054] In one embodiment of the present invention, a PID control system is further included. The PID control system is electrically connected to the flexible circuit board 1. The PID control system regulates the temperature rise rate in real time by adjusting the duty cycle of the voltage across the heating component 3, including:

[0055]

[0056] Where: u(k) represents the output quantity; e(k) represents the current error value, which is equal to the difference between the target value and the current output quantity; e(k-1) represents the previous error value, K P K represents the proportionality coefficient. I Represents the integration time constant, corresponding to parameters I and K. D This represents the differential coefficient.

[0057] In industrial process control, a control system that uses the proportional, integral, and derivative of the error generated by comparing the real-time data acquired from the controlled object with the given value is called a PID (Proportional Integral Derivative) control system. PID control systems have advantages such as simple principle, strong robustness, and wide applicability. They are a mature and widely used control system. Currently, there are few methods for microheater temperature control. In this embodiment, the PID control system adjusts the duty cycle of the voltage across the heating element 3 to regulate the real-time temperature rise rate of the microheater. The integrated PID control system regulates the surface temperature of the microheater in real time, ensuring rapid temperature rise and thus shortening the microheater's temperature response time.

[0058] In one embodiment of the present invention, there is a gap between the heating element 3 and the micro-temperature sensor 4. This gap is for electrical safety and to prevent short circuits. The size of the gap between the heating element 3 and the micro-temperature sensor 4 is not limited. Optionally, the distance between the heating element 3 and the micro-temperature sensor 4 is 40-50 μm. In this embodiment, the distance between the heating element 3 and the micro-temperature sensor 4 is optionally 45 μm, which facilitates installation and ensures electrical safety. With the distance between the heating element 3 and the micro-temperature sensor 4 set within this range, the micro-temperature sensor can effectively measure the temperature of the heating element, improving the accuracy of temperature measurement.

[0059] In one embodiment of the present invention, further, in the filled curve structure formed by the extension of the metal material, the distance between adjacent metal materials is d1, and the width W1, thickness H1, and distance d1 satisfy the following formula:

[0060] W1≤d1

[0061] H1 < W1

[0062] W1+d1≤400μm.

[0063] The micro-temperature sensor 4 has a width of W2, a length of L2, and a thickness of H2. There is a gap of d2 between the heating component 3 and the micro-temperature sensor 4, and the distance between the wires of adjacent micro-temperature sensors 4 is d3, satisfying the following formula:

[0064] H2 = H1

[0065] L2≥1 / 12L1

[0066] W2≤(d1-2d2-d3) / 2.

[0067] Optionally, the width W1 of the heating element 3 ranges from 180 to 210 μm, the thickness H1 ranges from 250 to 300 nm, and the distance d1 between adjacent metal materials of the heating element 3 ranges from 180 to 240 μm, which can produce a uniform temperature distribution and rapidly increase the temperature. Further, the width W2 of the micro-temperature sensor 4 is 35 to 45 μm, the thickness H2 is 250 to 300 nm, the distance d3 between the wires of adjacent micro-temperature sensors 4 is 25 to 30 μm, and the micro-temperature sensor 4 is disposed within the structural groove of the filling curve structure of the heating element 3. The width of the micro-temperature sensor is 35 to 45 μm, and the resistance is defined by the following formula:

[0068]

[0069] The smaller the line width, the smaller the cross-sectional area s, and the larger the resistance value, the more resistance value can be generated when the temperature changes; the spacing between the wires of adjacent micro temperature sensors 4 is for electrical safety and more accurate measurement of the temperature of the heating element.

[0070] In one embodiment of the present invention, the flexible circuit board 1 further includes pads 6. The specific number and structure of the pads 6 are not limited here. Optionally, the number of pads 6 is greater than or equal to the number of the first electrode 3-1 and the second electrode 4-1. Optionally, in this embodiment, the number of pads 6 is equal to the number of the first electrode 3-1 and the second electrode 4-1. The heating component 3 includes the first electrode 3-1, the micro temperature sensor 4 includes the second electrode 4-1, and the pads 6 are electrically connected to the first electrode 3-1 and the second electrode 4-1 respectively.

[0071] In one embodiment of the present invention, the invention further includes a conductive adhesive 5, which is an adhesive that exhibits a certain degree of conductivity after curing or drying. It can connect various conductive materials together, forming an electrical pathway between the connected materials. The mutual contact between conductive particles forms a conductive pathway, giving the conductive adhesive conductivity. The stable contact between particles in the adhesive layer is caused by the curing or drying of the conductive adhesive. Before curing or drying, the conductive particles exist separately in the adhesive, without continuous contact with each other, and are therefore in an insulating state. After the conductive adhesive cures or dries, the volume of the adhesive shrinks due to the evaporation of the solvent and the curing of the adhesive, resulting in a stable and continuous state between the conductive particles, thus exhibiting conductivity. The specific type of conductive adhesive is not limited here; conductive silver paste, conductive gold paste, conductive copper paste, and conductive carbon paste are all acceptable options. Further, in this embodiment, conductive adhesive 5 is optionally conductive silver paste. The pads 6 are electrically connected to the first electrode 3-1 and the second electrode 4-1 respectively through the conductive adhesive 5. The specific shape of the conductive adhesive 5 is not limited here; it can be chosen to be able to respectively adhere and connect the pads to the first electrode 3-1 and the second electrode 4-1. The conductive adhesive can form a sufficiently strong joint, stably connecting the pads and the first and second electrodes, ensuring the overall stability of the microheater. Furthermore, the microheater also includes a power supply with a voltage of 24V to ensure rapid heating of the microheater. Additionally, the resistance change of the micro-temperature sensor is measured by an external control circuit and the real-time temperature value is displayed on the screen.

[0072] In one embodiment of the present invention, the heating component 3 is further provided with an insulating layer. The specific material and thickness of the insulating layer are not limited here, nor is the method of providing the insulating layer limited. Optionally, the insulating layer can be set as an insulating layer with high thermal conductivity to avoid the insulating layer affecting the heating effect of the heating component. Further, optionally, in this embodiment, the material of the insulating layer is polydimethylsiloxane (PDMS). Polydimethylsiloxane, also known as dimethyl silicone oil, varies in appearance from a colorless and transparent volatile liquid to a liquid with extremely high viscosity or silica gel, depending on the relative molecular mass. It is odorless, highly transparent, and has heat resistance, cold resistance, small viscosity change with temperature, water resistance, low surface tension, and thermal conductivity with a thermal conductivity coefficient of 0.134-0.159 W / (m·K). The light transmittance is 100%. Dimethyl silicone oil is non-toxic and odorless, and has physiological inertness and good chemical stability. It has good electrical insulation, weather resistance, and hydrophobicity, and high shear resistance. It can be used for a long time at temperatures ranging from -50℃ to 200℃. It has excellent physical properties and can be used for moisture-proof insulation. The thickness of the insulation layer is not limited here. Optionally, the thickness of the insulation layer is 2μm-4μm. Further, in this embodiment, the thickness of the insulation layer is optionally 3μm. Insulation layers within this thickness range can have good insulation and thermal conductivity, without affecting the rapid heating of the heating component, and can also ensure electrical safety.

[0073] This embodiment, by setting the heating element as a filled curve structure, can improve the order of the wiring within a limited area, resulting in uniform temperature distribution. By extending the micro-temperature sensor from the center of the filled curve structure outwards and adapting it to the structure, the temperature of the heating element can be measured more accurately. A PID control system is also included. When a voltage is applied across the electrodes of the heating element, and current flows through the current-carrying wire, the heating element generates a temperature field due to Joule heating. The micro-temperature sensor integrated around the heating element accurately reflects the surface temperature of the heating element based on the resistance effect. The PID control system adjusts the duty cycle of the voltage across the heating element to regulate the temperature rise rate of the micro-heater in real time, thereby shortening the temperature response time of the micro-heater. Furthermore, the circuit width of the heating element, the circuit width of the micro-temperature sensor, and the gap between the heating element and the micro-temperature sensor are limited, ensuring electrical safety and further guaranteeing the accuracy, uniformity, and efficiency of temperature detection. This embodiment has a simple structure, uniform micro-heater temperature, and high accuracy of the integrated micro-temperature sensor, meeting the high requirements of polymerase chain reaction (PCR) chips and facilitating widespread adoption.

[0074] Example 2

[0075] A method for fabricating a microheater, used to fabricate the heating element 3 and the microtemperature sensor 4 as described in any one of the above. Figure 5 A flowchart illustrating a method for preparing a heating component according to an embodiment of the present invention is shown; Figure 6 A diagram illustrating a method for manufacturing a heating element according to an embodiment of the present invention is shown; as follows: Figure 5 , Figure 6 As shown, it includes:

[0076] A mask is fabricated, comprising a heating element 3, a filled curve structure, and a micro-temperature sensor 4. The specific structure of the mask is not limited here. Optionally, it can be a structure adapted to the periphery of the filled curve structure, or it can be any structure larger than the periphery of the filled curve structure. The specific content of the filled curve structure is not limited here. Optionally, it can be one of a Peano space filled curve structure, a triangular filled curve structure, or a flow snake filled curve structure. In this embodiment, the filled curve structure is optionally a flow snake filled curve structure. The mask is composed of a glass / quartz substrate, a chromium layer, and a photoresist layer.

[0077] Photoresist is spin-coated onto substrate 2, and the mask is placed on the substrate 2 coated with photoresist for exposure. The uncoated area after exposure is the heating component and the micro-temperature sensor area. The specific content of substrate 2 is not limited here. Optionally, the material of substrate 2 is silicon wafer, glass sheet, ceramic or PI film. Further, in this embodiment, the material of substrate 2 is silicon wafer. The specific content of photoresist is not limited here. Photoresist refers to a photoresist thin film material whose solubility changes when irradiated or irradiated by ultraviolet light, electron beam, ion beam, X-ray, etc. It is a photosensitive mixed liquid composed of three main components: photosensitive resin, sensitizer and solvent. In the photolithography process, it is used as an anti-corrosion coating material. When semiconductor materials are processed on the surface, if an appropriate selective photoresist is used, the desired image can be obtained on the surface. It is not limited here whether the photoresist is positive or negative. In the photoresist process, after the coating is exposed and developed, the exposed part is dissolved and the unexposed part remains. The coating material is positive photoresist. If the exposed portion is retained while the unexposed portion is dissolved, the coating material is a negative photoresist. In this embodiment, optionally, the photoresist is a positive photoresist. The type of exposure light source and radiation source is not limited here; optional options include ultraviolet photoresist, deep ultraviolet photoresist, X-ray photoresist, electron beam photoresist, ion beam photoresist, etc. Optionally, in this embodiment, the photoresist is an ultraviolet photoresist, which is convenient to manufacture and easy to promote.

[0078] After exposure and development, the photoresist-coated substrate 2 is removed from the mask, and metal is sputtered onto the developed substrate 2 surface using magnetron sputtering. The working principle of magnetron sputtering is that electrons, under the influence of an electric field E, collide with argon atoms as they fly towards the substrate, ionizing them to produce Ar ions and new electrons. The new electrons fly towards the substrate, while the Ar ions, under the influence of the electric field, accelerate towards the cathode target and bombard the target surface with high energy, causing sputtering of the target material. In the sputtered particles, neutral target atoms or molecules are deposited on the substrate to form a thin film, while the generated secondary electrons are affected by electric and magnetic fields, resulting in a drift in the direction indicated by E (electric field) × B (magnetic field), abbreviated as E×B drift, whose trajectory approximates a cycloid. If a toroidal magnetic field is used, the electrons move in a circular motion on the target surface in an approximate cycloid manner. Their movement path is not only very long, but they are also confined to a plasma region near the target surface, where a large amount of Ar is ionized to bombard the target material, thus achieving a high deposition rate. As the number of collisions increases, the energy of the secondary electrons is exhausted, and they gradually move away from the target surface, eventually depositing on the substrate under the influence of the electric field E. Because the energy of these electrons is very low, the energy transferred to the substrate is minimal, resulting in a low substrate temperature rise. The type and thickness of the sputtered metal are not limited here; optionally, the sputtered metal can be gold, platinum, copper, titanium, or a nickel-chromium alloy. Optionally, in this embodiment, the sputtered metal is gold, and the thickness of the sputtered metal can be selected as 250–300 nm, and more preferably, the thickness of the sputtered metal is 300 nm.

[0079] The unexposed photoresist on the developed substrate 2 is removed using a stripping process. What remains is a metal pattern with a filled curve structure, including a heating element 3 and a micro-temperature sensor 4. The stripping process involves coating the substrate 2 with photoresist, exposing it, and developing it. Using a photoresist film with a specific pattern as a mask, the required metal is evaporated along with the photoresist. Then, while removing the photoresist, the metal on the photoresist film is also stripped away, leaving only the metal with the original pattern on the substrate. The advantages of the metal stripping process are that it can obtain submicron patterns with steep edges and precise pattern dimensions. The specific stripping process used is not limited here; optionally, in this embodiment, acetone is used for stripping.

[0080] Insulation is achieved by spin-coating an insulating medium onto the metal surface of the substrate 2 after a peeling process using a spin coater. The specific content and structure of the insulating medium are not limited here. Optionally, it is an insulating medium with high thermal conductivity to avoid the influence of the insulating layer on the heating effect of the heating component. Further, in this embodiment, the material of the insulating layer is polydimethylsiloxane (PDMS). The thickness of the insulating layer is not limited here. Optionally, the thickness of the insulating layer is 2μm-4μm. Further, in this embodiment, the thickness of the insulating layer is 3μm. Insulating layers within this thickness range can have good insulation and thermal conductivity, without affecting the rapid heating of the heating component, and can also ensure electrical safety.

[0081] A substrate 2 with a heating element 3 and a micro temperature sensor 4 is obtained.

[0082] This embodiment uses a combination of micro-nano lithography and magnetron sputtering to process the heating component. It eliminates the need for a complex metal corrosion process to obtain the designed micro-heater shape, greatly simplifying the processing difficulty and improving the precision of the processed structure.

[0083] In one embodiment of the present invention, it further includes:

[0084] A substrate 2 with a heating element 3 and a micro temperature sensor 4 is disposed on a flexible circuit board 1;

[0085] The conductive adhesive 5 is used to connect the pads 6 on the flexible circuit board 1 to the first electrode 3-1 of the heating component 3 and the second electrode 4-1 of the micro temperature sensor 4, respectively.

[0086] The PID control system is electrically connected to the flexible circuit board 1.

[0087] This embodiment uses a PID control system to control the temperature of the heating element, which improves the timeliness of temperature control.

[0088] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

[0089] The above description does not provide detailed explanations of the technical aspects of each layer's patterning and etching. However, those skilled in the art should understand that various methods existing in the prior art can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above.

[0090] The present invention has been described above with reference to embodiments thereof. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. The scope of the invention is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A micro heater, characterized in that, include: The flexible circuit board (1), substrate (2), heating element (3) and micro temperature sensor (4) are provided. The substrate (2) is disposed on the flexible circuit board (1), and the heating element (3) is disposed on the substrate (2). The heating element (3) is configured as a filled curve structure. The micro temperature sensor (4) extends from the center of the filled curve structure of the heating element (3) to the periphery of the filled curve structure of the heating element (3) and is adapted to the filled curve structure of the heating element (3). The flexible circuit board (1) is electrically connected to the heating element (3) and the micro temperature sensor (4) respectively. The filling curve structure is formed by extending a metal material with a width of W1 and a thickness of H1 along a predetermined curve path. The predetermined curve path includes at least one of a Piano space filling curve, a triangle filling curve, and a serpentine filling curve. The micro temperature sensor (4) is arranged along the curve path and is located in the gap of the curve path. There is a gap between the heating element (3) and the micro temperature sensor (4), and the gap is 40-50 μm; In the filled curve structure formed by the extension of the metal material, the distance between adjacent metal materials is d1, and the width W1, thickness H1, and distance d1 satisfy the following formula: W1≤d1; H1 < W1; W1+d1≤400μm.

2. The micro heater according to claim 1, characterized in that, It also includes a PID control system, which is electrically connected to the flexible circuit board (1). The PID control system calculates and outputs the duty cycle of the voltage across the heating component (3) to regulate the temperature rise rate in real time, including: ； Where: u(k) represents the output quantity; e(k) represents the current error value, which is equal to the difference between the target value and the current output quantity; e(k-1) represents the previous error value, K P K represents the proportionality coefficient. I Represents the integration time constant, corresponding to parameters I and K. D This represents the differential coefficient.

3. The micro heater according to claim 1, characterized in that, The micro-temperature sensor (4) has a width of W2 and a thickness of H2. There is a gap of d2 between the heating component (3) and the micro-temperature sensor (4). The distance between the wires of adjacent micro-temperature sensors (4) is d3, satisfying the following formula: H2 = H1; W2≤(d1-2d2-d3) / 2.

4. The micro heater according to claim 1, characterized in that, The flexible circuit board (1) includes a pad (6), the heating component (3) includes a first electrode (3-1), the micro temperature sensor (4) includes a second electrode (4-1), and the pad (6) is electrically connected to the first electrode (3-1) and the second electrode (4-1) respectively.

5. The microheater according to claim 4, characterized in that, It also includes conductive adhesive (5), and the pads (6) are electrically connected to the first electrode (3-1) and the second electrode (4-1) through the conductive adhesive (5).

6. A method for preparing a micro heater, characterized in that: For preparing the microheater as described in any one of claims 1-5, comprising: Fabricate a mask including a heating element (3) filling curve structure and a micro temperature sensor (4) structure; Photoresist is spin-coated onto the substrate (2), and the mask is placed on the substrate (2) coated with photoresist for exposure. After the photoresist-coated substrate (2) is exposed and developed, the mask is removed, and metal is sputtered onto the surface of the developed substrate (2) using a magnetron sputtering process. The unexposed photoresist on the developed substrate (2) was removed by a stripping process; Insulation is achieved by spin coating an insulating medium onto the metal surface of a substrate (2) after a peeling process using a spin coater. A substrate (2) with a heating element (3) and a micro temperature sensor (4) is obtained.

7. The method for preparing a microheater according to claim 6, characterized in that, Also includes: A substrate (2) with a heating element (3) and a micro temperature sensor (4) is disposed on a flexible circuit board (1); The pads (6) on the flexible circuit board (1) are connected to the first electrode (3-1) of the heating component (3) and the second electrode (4-1) of the micro temperature sensor (4) respectively by conductive adhesive (5); The PID control system is electrically connected to the flexible circuit board (1).

Images