Flexible multifunctional microsystem manufacturing method based on local area block doping

Abstract

The invention relates to a manufacturing method of a flexible multifunctional microsystem based on local area block doping, and belongs to the technical field of micro-nano machining-microsystems. The invention relates to a design and manufacturing method of a flexible multifunctional integrated microsystem based on a graphene doped material. The flexible multifunctional integrated microsystem needs a soft and stretchable material. The femtosecond laser-induced graphene has adjustable physical and chemical properties, can realize nano-scale to meter-scale cross-scale manufacturing, and has special value in the development of a flexible bit system. Therefore, the functional unit is mainly composed of femtosecond laser induced graphene. According to the sensor, the unique performance of graphene is utilized, and the sensor with high sensitivity and high stability is constructed on an ultrathin flexible substrate.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a flexible multifunctional microsystem based on local block doping, belonging to the technical field of micro-nano processing-microsystem. Background Art

[0002] Flexible multifunctional microsystem: an advanced technology that combines flexible electronic technology with intelligent microsystem design. This system is made of bendable, stretchable, and even wearable materials, so that it can be used on various irregular or dynamically changing surfaces. The development of flexible intelligent microsystems combines the functions of traditional hard electronic devices with the characteristics of flexible substrate materials, enabling them to better adapt to complex or changing physical environments. The main features are: ① Flexibility and elasticity ② Integrated sensing, processing, communication and execution functions ③ Low power design, combined with energy harvesting technology ④ Intelligent interaction. The main application scenarios include: ① Used to develop various health monitoring systems, such as smart watches, health tracking bracelets, and more advanced physiological monitoring equipment to continuously track heart rate, blood pressure, body temperature, etc. ② Directly integrate sensors and circuits in textiles to realize smart clothing, such as functional clothing that can adjust temperature, change color or track sports performance. ③ Skin repair patches can monitor moisture and bacteria levels in real time during wound healing, or be used to monitor chronic pain and muscle activity. ④ Environmental monitoring can be arranged in different corners of the city and integrated into building materials to monitor air quality, temperature and humidity, as well as pedestrian flow and safety.

[0003] Design of functional unit blocks of flexible multifunctional microsystems: Flexible multifunctional microsystems are usually composed of multiple functional units, each of which performs different tasks, such as sensing, processing, communication, and energy management. In order to design effective functional unit blocks, key aspects such as integration, interoperability, reliability, and flexibility need to be considered. First, determine the functions that the microsystem needs to complete and decompose these functions into independent or collaborative units, such as: Sensing unit: used for environmental monitoring, biological signal detection, etc. Processing unit: responsible for data analysis and processing. Communication unit: realizes data transmission and reception. Energy unit: provides power management and energy storage functions. Second, the selection of suitable materials is the key to designing flexible microsystems, and the materials need to have the following properties: flexibility and plasticity, conductivity, biocompatibility, etc. Third, effective integration between functional units is crucial, and a compact layout should be designed to save space while ensuring that the units do not interfere with each other. Ensure the reliability of electrical and mechanical connections, and the data and command flow between units should be smooth, coordinated by microcontrollers or integrated circuits.

[0004] Laser-induced graphene (LIG) carbon precursor doping technology: refers to the process of adding specific dopants to the precursor material during the laser preparation of graphene to improve the performance of the final graphene or give it specific functions. Doping can change the electronic structure of graphene, thereby affecting its electrical, thermal or chemical properties. This technology has shown important potential in improving the performance of LIG and expanding its application areas. Doping usually involves introducing non-carbon elements (such as nitrogen, boron, sulfur, metal atoms, etc.) or other functional materials (MXene, black phosphorus, metal oxides) into the carbon network of graphene. These dopants can generally affect the properties of graphene in the following ways: ① Adjustment of electronic properties. By changing the number and distribution of electrons in the carbon grid, dopants can change the conductivity, semiconductor behavior and magnetism of graphene. ② Enhancement of chemical activity. Certain dopants can increase the chemical activity of the graphene surface, making it more suitable for applications in sensors, batteries, capacitors and other fields. ③ Improvement of thermal stability: Doping can affect the thermal stability of the material, making it suitable for use in high temperature environments. Laser-induced preparation of doped graphene is mainly achieved through the following steps:

[0005] ① Precursor selection and dopant addition: Select a suitable carbon-containing material as a precursor and add the dopant evenly to the precursor. This can be done by mixing powders, solution impregnation, or chemical vapor deposition. ② Laser processing: Use laser equipment to process the doped precursor. The parameters of the laser (such as power, scanning speed, and focal length) need to be precisely controlled based on the precursor material and the desired graphene properties. ③ Post-processing: After laser treatment, some post-processing steps such as cleaning, heat treatment, or chemical treatment may be required to remove unreacted dopants or improve the properties of graphene. Summary of the invention

[0006] The purpose of the present invention is to solve the material doping problem in the design and manufacturing process of flexible multifunctional integrated microsystems, and to provide a method for manufacturing flexible multifunctional microsystems based on local block doping. The present invention is based on a design and manufacturing method for a flexible multifunctional integrated microsystem of graphene-doped materials. Flexible multifunctional integrated microsystems require soft and stretchable materials. Femtosecond laser-induced graphene has adjustable physical and chemical properties and can achieve cross-scale manufacturing from nanometers to meters, and has special value in the development of flexible bit systems. Therefore, the functional unit of the present invention is mainly composed of femtosecond laser-induced graphene. The sensor utilizes the unique properties of graphene to construct a highly sensitive and highly stable sensor on an ultra-thin flexible substrate.

[0007] Investigate the doping precursors required for the power supply area, circuit area, and sensor area, then design the CAD processing layout of the microsystem, prepare the flexible precursor based on the layout design and local block doping technology, and then induce various functional unit arrays and circuits on the precursor film by femtosecond laser induction. Finally, use PDMS to cast on its surface or directly bond PDMS film encapsulation, and evaluate its performance by calibrating and testing the microsystem.

[0008] The purpose of the present invention is achieved through the following technical solutions.

[0009] Step 1: Partition

[0010] Divide the substrate into regions according to the requirements, the regions include: power region, circuit region and sensor region; configure corresponding precursor solutions for each region: configure a precursor solution doped with transition metal elements for the power region; configure a precursor solution doped with high conductivity metals for the circuit region; configure a precursor solution doped with two-dimensional materials and organic metal frameworks for the sensor region;

[0011] Step 2: Doping

[0012] According to the positions of the power area, circuit area and sensor area on the substrate, a doctor blade is used in combination with block mask technology to apply the configured precursor solution in different areas. The precursor solutions with different functions correspond to the functional areas divided on the substrate one by one. The thermal annealing process is used for post-processing to convert the precursor solution with multiple doping materials into a flexible film.

[0013] Step 3: Laser Direct Writing

[0014] The flexible film is processed using femtosecond laser direct writing technology, and the three-dimensional free-motion translation stage is used to move the sample to any position through computer control to achieve patterned preparation and interconnection of different functional units;

[0015] Beneficial effects:

[0016] First, the doped precursor material can be controlled according to demand, and a mask can be used to prepare precursors of different functional units on a flexible film, and the positions of the processing layout correspond one to one, which is convenient for the subsequent laser one-step direct writing to manufacture each functional unit. Compared with traditional methods, local block doping technology makes it possible to integrate multiple functions in a relatively small space. This not only improves the complexity and performance of the system, but also greatly expands its potential application areas. Finally, the materials are cheap and easy to obtain, which greatly reduces costs. Local doping technology can optimize the electrical, thermal and mechanical properties of the device, reduce unnecessary performance loss or failure risk caused by uniform doping, and significantly improve the overall performance and reliability of the microsystem.

[0017] Secondly, ultra-thin flexible polymer films need to overcome the temperature changes during the processing process that will cause the material to deform. Femtosecond laser processing technology has an ultra-short pulse time (10 -15 s) and ultra-high instantaneous peak power (10 14 W / cm 2 ), and exhibits strong nonlinear and non-equilibrium characteristics in the process of interaction with materials. When processing ultra-thin flexible films, the thermal effect is low, which greatly improves the manufacturing accuracy and can achieve cross-scale manufacturing from nanometers to meters. It has little impact on the material and avoids the damage to the material caused by temperature changes in traditional processing methods. The laser-induced graphene method is simple, fast and environmentally friendly. At the same time, it can realize the preparation of materials with different functions based on local block doping, which provides a feasible method for the integrated manufacturing of multifunctional flexible microsystems. Through femtosecond laser ablation, stripping, doping and functionalization, the electrical conductivity, thermal conductivity, mechanical and physical and chemical properties of graphene are regulated to achieve integrated manufacturing of flexible multifunctional microsystems. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 To investigate the doping materials required for each functional unit;

[0019] Figure 2 Prepare precursor films for selected materials;

[0020] Figure 3 It is a laser-induced graphene functional unit;

[0021] Figure 4 Laser-induced graphene functional units on locally doped precursor films. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] Example 1

[0024] Step 1: Investigate the doping materials required for the power supply area, circuit area, and sensor area

[0025] like Figure 1 , conduct an in-depth review of the literature on graphene doped materials to understand the existing research results and methods. And conduct research on batteries, capacitors, circuits, sensors, etc. to determine the required functional materials.

[0026] Step 2: Select materials to prepare precursor films

[0027] like Figure 2In this design, PAA (polyamic acid, a precursor solution of PI, which forms PI after annealing) is selected as the substrate of the carbon-rich precursor. Before annealing, PAA is in a solution state and can be doped arbitrarily. Cobalt chloride is selected as the dopant of the power module, chloroauric acid is selected as the dopant of the logic circuit module, and the two-dimensional material MXene is selected as the dopant of various sensors. According to the design drawing, the mask is customized to achieve local block doping. Finally, thermal annealing is performed to prepare a flexible precursor doped substrate.

[0028] Step 3: Laser-induced graphene functional unit

[0029] like Figure 3 As shown in Figure 4, a 100-micron-thick precursor film is placed on a three-dimensional movable translation stage; the Z axis is adjusted on the PC side, and the laser is focused on the sample surface through the focusing objective lens to present a clear image; the parameters are changed on the PC side, the laser repetition frequency is set to 1MHz, and the focusing objective lens is selected to be 20X for processing; the laser power is adjusted by adjusting the angle of the attenuation plate, and the power range is 300-600MW; the parameters are set according to the above steps, and the graphene functional unit is processed on the precursor film through the set program.

[0030] During the laser direct writing process on the surface of the carbon-rich precursor, the chemical bonds in the precursor will be destroyed and the gas will be released, thus forming a layered porous LIG structure and realizing the preparation of various functional units. The formation mechanism of LIG is mainly the photochemical effect and photothermal effect of the laser. The layered structure of LIG makes it very sensitive to external strain, and the resistance of LIG is affected by the distance between the layers.

[0031] Step 4: Packaging

[0032] After conducting the conductivity test, we use PDMS solution casting or PDMS film bonding to cover the areas on the surface that need to be passivated.

[0033] Prepare PDMS precursor and cross-linking agent, mix them in a specific ratio, and mix the mixture thoroughly with a stirrer until a uniform PDMS solution is obtained. Pour the PDMS solution on the surface of the graphene device, and apply the PDMS to the desired thickness with a scraper or roller. The thickness of the PDMS can be controlled by adjusting the height of the scraper or roller. It should be noted here that it can be done under some measurement methods, and the thickness should be kept at the level of hundreds of microns. Place the graphene device coated with PDMS in a vacuum to remove bubbles. Place the sample on a hot plate and cure the PDMS at a certain temperature. The curing temperature and time depend on the PDMS formula used. Once the PDMS is cured, the PDMS layer can be gently peeled off from the substrate. Finally, the encapsulation layer is completely peeled off, and the encapsulated graphene device is not damaged.

[0034] At the same time, encapsulating a layer of PDMS increases the flexibility of the sensor, and due to its smooth surface and waterproof properties, the sensor is adapted to more special scenarios.

[0035] In summary, the present invention relates to a design and laser manufacturing method of a flexible multifunctional microsystem based on local block doping. The point that needs to be protected is that we use a mask-based precursor local block doping process and a femtosecond laser-induced graphene circuit as support to produce a flexible multifunctional microsystem, and through research and experiments, we adapt to the current difficulties in the design and manufacture of flexible multifunctional microsystems. Since the flexible multifunctional microsystem can achieve low cost, simple process, integrated rapid cross-scale manufacturing, this is a major breakthrough in the design and manufacture of flexible multifunctional microsystems.

[0036] The specific description above further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for manufacturing a flexible multifunctional microsystem based on local block doping, characterized in that: The following steps are included: Step 1: Partition Divide the substrate into regions according to the requirements, the regions include: power region, circuit region and sensor region; configure corresponding precursor solutions for each region: configure a precursor solution doped with transition metal elements for the power region; configure a precursor solution doped with high conductivity metals for the circuit region; configure a precursor solution doped with two-dimensional materials and organic metal frameworks for the sensor region; Step 2: Doping According to the positions of the power area, circuit area and sensor area on the substrate, a doctor blade is used in combination with block mask technology to apply the configured precursor solution in different areas. The precursor solutions with different functions correspond to the functional areas divided on the substrate one by one. The thermal annealing process is used for post-processing to convert the precursor solution with multiple doping materials into a flexible film. Step 3: Laser Direct Writing The flexible film is processed using femtosecond laser direct writing technology, and a three-dimensional free-moving translation stage is used to move the sample to any position through computer control to achieve patterned preparation and interconnection of different functional units.

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