A non-contact in-situ manufacturing method of a curved surface conformal resistor

Abstract

The application discloses a kind of non-contact in-situ manufacturing methods of curved surface conformal resistance, first according to target resistance value demand and pin gap etc. Resistance verification selects resistance paste according to manufacturing condition;Path planning is carried out to piezoelectric jet device, so that resistance paste jet droplet is accurately deposited to specified position of curved surface substrate;In-situ infrared drying and curing and laser sintering functionalization are carried out to print curved surface conformal resistance;The manufacturing precision of curved surface conformal resistance is improved by laser resistance regulating method;Piezoelectric jet resistance protective layer on the surface of curved surface conformal resistance is packaged.Based on the characteristics of jet printing, the application can avoid the complex path planning and nozzle interference risk of contact printing curved surface conformal resistance, and laser sintering can solve the problem of limited materials in the manufacturing process of high-temperature resistant resistance materials, to solve the problem of stable manufacturing of curved surface conformal resistance on any curved surface.

Description

Technical Field

[0001] This invention relates to the field of resistive element processing and manufacturing technology, and in particular to a non-contact in-situ manufacturing method for a conformal surface resistor. Background Technology

[0002] Traditional planar integrated circuits primarily use resistive elements by depositing resistive material onto an insulating substrate using methods such as magnetron sputtering or screen printing of resistive paste. These are then encapsulated with a protective layer to create planar chip resistors, which are then mounted on circuit boards via surface mounting or soldering. However, in curved electronic circuits, even with specialized equipment, surface-mount planar resistors experience assembly stress at their edges, leading to poor assembly reliability. Soldering, on the other hand, can affect the electromagnetic properties of curved electronic components. Therefore, traditional manufacturing methods cannot guarantee the reliable production of conformal resistive elements for curved surfaces.

[0003] 3D printing technology provides a new solution for the manufacture of resistive elements. It can directly manufacture resistive elements and flexibly control the resistive structure. For example, the patent application entitled "A method for preparing and adjusting the resistance value of a 3D printed resistor" (publication number: CN113628821A) is used. However, for the manufacture of conformal resistors on curved surfaces, the use of contact printing methods such as extrusion printing is limited by the technology itself. On large-scale curved or complex curved surfaces, the small receiving distance can easily lead to nozzle interference. The use of non-contact printing methods such as inkjet printing and aerosol jetting is limited by the printing materials and can only print low-viscosity slurries (Ramon E, Sowade E, Martinez-Domingo C, et al. Large-scale fabrication of all-inkjet-printed resistors and WORM memories on flexible polymer films with high yield and stability[J]. Flexible and Printed Electronics, 2021, 6(1): 015003.).

[0004] High-temperature resistant resistive materials require processing in a high-temperature tunnel furnace at temperatures above 800°C after functionalization, as illustrated in the patent application titled "A Thin-Film Resistor and Its Preparation Method" (Publication No.: CN118053640A). These materials have traditionally been manufactured on high-temperature substrates such as ceramics. However, tunnel furnace sintering is not suitable for most electronic substrates, and it is completely unsuitable for surfaces already containing electronic components. Furthermore, there is currently no mature method for in-situ functionalization of resistive elements. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a non-contact in-situ manufacturing method for conformal resistors. The piezoelectric jetting method can realize the stable printing of conformal resistor elements, while the laser sintering method can solve the material limitation problem in the manufacturing process of high-temperature resistant resistor materials, thus realizing the stable manufacturing of conformal resistors on any curved surface.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A non-contact in-situ manufacturing method for a conformal resistor includes the following steps:

[0008] Step S1: Based on information including resistor pin gap, manufacturing range, and target resistance value, and by calculating the planar sheet resistance parameters of the material, select the material and conduct resistance testing to verify the piezoelectric jet droplet deposition area and thickness, and determine the resistor paste.

[0009] Step S2: Based on step S1, use computer-aided design software or 3D scanning technology to obtain a 3D model of the curved device, and perform piezoelectric jetting path planning, piezoelectric deposition droplet control for complex curved surfaces, and control of the conformal resistance of the curved surface on the obtained model.

[0010] Step S3: Fix the curved substrate to the printing platform, and use the piezoelectric jetting device to spray the resistive material from the nozzle according to the path set in step S2. The resulting jetting droplets are deposited non-contactly onto the designated position of the curved substrate to complete the printing of the curved conformal resistor.

[0011] Step S4: The conformal resistor from step S3 is functionalized by in-situ infrared drying and curing and in-situ laser sintering.

[0012] Step S5: Perform resistance value testing on the functionalized conformal resistor from step S4, and correct the conformal resistor using laser trimming.

[0013] Step S6: The surface resistive protective layer is piezoelectrically jet-printed onto the functionalized conformal resistive surface modified in step S5 to complete the fabrication.

[0014] In step S1, the resistive slurry is a high-temperature ruthenium-based slurry with a viscosity of 100–300 Pa·s. The sheet resistance is selected from resistors of different orders of magnitude, such as 10Ω / □ / mil, 100Ω / □ / mil, 1kΩ / □ / mil, and 10kΩ / □ / mil.

[0015] In step S2, the piezoelectric deposition droplets on complex curved surfaces are processed by adjusting the number of piezoelectric jet dispensing operations and the fusion state between consecutive points.

[0016] In step S2, the resistance value of the conformal resistor for complex curved surfaces is adjusted by changing the shape and thickness of the piezoelectric jet printing resistor.

[0017] In step S2, the resistance value of the conformal resistor on the complex curved surface is adjusted so that the thickness of the piezoelectric jet droplets deposited on the curved surface is 0.03 to 0.1 mm.

[0018] In step S3, the distance between the piezoelectric injection valve nozzle and the curved substrate surface is 2-6 mm.

[0019] In step S3, the parameters used by the piezoelectric jet valve include nozzle diameter, piezoelectric jet valve rise time, piezoelectric jet valve fall time, piezoelectric jet valve opening time, piezoelectric jet valve descent force, and piezoelectric jet valve delay time. Adjusting these parameters enables dispensing control of the piezoelectric jet device, thereby enabling control over the manufacturing of curved conformal resistive structures and patterns.

[0020] The in-situ infrared drying method in step S4 specifically refers to: using a thermal infrared lamp to heat the curved conformal resistor, which has been dried and cured at room temperature, to irradiate it in-situ to 100-150°C for 10-15 minutes to dry it.

[0021] The in-situ laser sintering method in step S4 specifically refers to the use of continuous laser to directly irradiate the ruthenium-based resistive material, thereby sintering and solidifying the curved conformal resistive material. The continuous laser power density is 0.5*10⁴~10*10⁴ W / cm². 2 The laser scanning speed is 1 to 10 mm / s.

[0022] In addition to considering the energy absorption and reception of the curved surface by the conformal resistance of the laser sintering process in step S4, the heating of the curved substrate during the sintering process also needs to be considered.

[0023] Step S5 specifically refers to: clamping the conformal resistor onto the laser trimming device, using a laser to ablate the resistor body according to the initial resistance value to change the width of the resistor body, and adjusting the resistance value of the conformal resistor to its design value.

[0024] In step S6, the protective layer material is polyimide (PI), glass glaze, polyether ether ketone (PEEK), etc. The protective layer is dried and cured using hot air circulation in a curing oven, as well as heat radiation curing and heat infrared lamp irradiation curing.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] This invention provides a non-contact in-situ manufacturing method for conformal resistors. It utilizes a piezoelectric jetting non-contact printing method to control the droplet fusion state and resistor shape, enabling the printing and flexible adjustment of conformal resistors. Through research on piezoelectric jetting technology, stable printing of high-viscosity, high-temperature resistant resistors can be achieved. An in-situ infrared drying method combined with a pre-sintering process ensures the conformal resistors are solidified and conformally preserved, improving the stability and uniformity of the manufacturing process. An in-situ laser sintering method is used to functionalize the high-temperature resistant resistors, solving the problem of substrate limitations in the manufacturing of high-temperature resistant resistor materials and enabling stable manufacturing of conformal resistor elements on arbitrary curved surfaces. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the non-contact in-situ manufacturing process of the conformal resistor for curved surfaces according to an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the spherical base used in an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of the conformal resistor printed on a curved surface using a piezoelectric jetting device according to an embodiment of the present invention.

[0030] Figure 4 This is a schematic diagram of the fusion of piezoelectric jet dispensing droplets in an embodiment of the present invention.

[0031] Figure 5 These are images showing the fusion of piezoelectric jet dispensing droplets according to an embodiment of the present invention; the fusion percentages are 5%, 15%, 25%, 50%, 75%, and 90%, respectively.

[0032] Figure 6 This is a fitting curve of droplet fusion state and corresponding resistance value in an embodiment of the present invention.

[0033] Figure 7 This is a schematic diagram illustrating the combination of droplet fusion state and resistor shape design in an embodiment of the present invention.

[0034] In the figure: 1-Curved substrate; 2-Curved conformal resistor; 3-Curved circuit; 4-Piezoelectric jet valve; 5-Piezoelectric jet droplet. Detailed Implementation

[0035] To more clearly explain the purpose and technical solution of this invention, the invention will be further described below in conjunction with embodiments and accompanying drawings. It should be understood that the embodiments described herein are merely illustrative and do not limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the protection scope of this invention.

[0036] Example 1: Refer to Figure 1A non-contact in-situ manufacturing method for a conformal resistor, comprising the following steps:

[0037] Step S1: Based on information including resistor pin gap, manufacturing range, and target resistance value, and by calculating the planar sheet resistance parameters of the material, select the material and conduct resistance testing to verify the piezoelectric jet droplet deposition area and thickness, and determine the resistor paste.

[0038] Step S2: Based on step S1, use computer-aided design software or 3D scanning technology to obtain a 3D model of the curved device, and perform piezoelectric jetting path planning, piezoelectric deposition droplet control for complex curved surfaces, and control of the conformal resistance of the curved surface on the obtained model.

[0039] Step S3: Fix the curved substrate to the printing platform, and use the piezoelectric jetting device to spray the resistive material from the nozzle according to the path set in step S2. The resulting jetting droplets are deposited non-contactly onto the designated position of the curved substrate 1 to complete the printing of the curved conformal resistor.

[0040] Step S4: The conformal resistor from step S3 is functionalized by in-situ infrared drying and curing and in-situ laser sintering.

[0041] Step S5: Perform resistance value testing on the functionalized conformal resistor from step S4, and correct the conformal resistor using laser trimming.

[0042] Step S6: The surface resistive protective layer is piezoelectrically jet-printed onto the functionalized conformal resistive surface modified in step S5 to complete the fabrication.

[0043] like Figure 2 As shown, in this embodiment, the curved substrate 1 is a sphere, and a curved conformal resistor 2 and a curved circuit 3 are manufactured on the curved substrate 1. The target resistance value is designed to be 200Ω±10% at different curvatures of the curved substrate 1, and the electrode spacing is 0.5mm. The thickness is based on the actual printing thickness, ranging from 20 to 50μm. The printing resistor paste is a high-temperature ruthenium-based resistor paste with a sheet resistance of 150±10Ω / □ / mil and a viscosity of 150±30Pa.s. The traditional sintering method is sintering in an atmospheric atmosphere in a tunnel furnace, with a peak temperature of 850±5℃ and a peak time of 9 to 11 minutes. The equipment is a piezoelectric jet valve combined with a six-degree-of-freedom robotic arm.

[0044] By editing the robotic arm's motion trajectory and adjusting its posture for different curvatures, the piezoelectric injection valve 4 can non-contactly deposit piezoelectric jet droplets 5 onto a designated location on the curved substrate 1 along the normal direction of the curved substrate 1. Figure 3As shown; after completing the piezoelectric jet resistor printing, it undergoes room temperature drying and leveling for 2 minutes, followed by infrared thermal lamp heating to maintain the curved surface shape. The infrared heating power is 100W-200W, with the power slowly increased to raise the temperature to 100-120℃ for 12-15 minutes. After completing the pre-sintering and curing step, the functionalized resistor paste is sintered using a continuous laser irradiation process through a defocused surface sintering process. Due to the relatively thick thickness of the printed resistor layer, multiple laser scans are required, with the laser power decreasing by 0.5*10⁴W / cm² in each scan. 2 The continuous laser power density is 1.0*10⁴~2*10⁴ W / cm². 2 The scanning speed increases by 0.5 mm / s, and the laser scanning speed is 3-10 mm / s.

[0045] The thickness of the laser-sintered conformal resistor is 40μm±5μm, and the bonding force with the curved substrate is ≥1N / mm. First, the functionalized conformal resistor is compared with the target value. If the resistance value is too large, laser resistance adjustment is performed. If the resistance value is too small or other resistance values ​​are too different, the resistance value is adjusted by re-optimizing the process parameters and the shape of the conformal resistor structure.

[0046] The curved substrate 1 is reliably fixed on the laser trimming machine using a fixture. The curved conformal resistor 2 and the curved circuit 3 have good contact and the resistance value is stable. By measuring the resistance value of the functionalized curved conformal resistor 2 and comparing it with the target resistance, the laser trimming pattern cutting resistor is designed to adjust the resistance value to the design value of the curved conformal resistor, with a resistance accuracy within ±3%. After comparing the resistance value of the manufactured curved conformal resistor with the target value and finding that it meets the requirements, the curved conformal resistor with the trimmed resistance is encapsulated with a surface protective layer. The encapsulation technology is piezoelectric jetting, and the encapsulation material is polyimide (PI). After printing, the PI material is heated and polymerized and cured using a thermal infrared lamp with a power of 500W.

[0047]

[0048] Example 2: Unlike Example 1, refer to... Figure 4 The droplet fusion state is controlled by adjusting the droplet jetting spacing, such as designing fusion ratios of 5%, 25%, 50%, 75%, and 95%. The electrode spacing is 6mm, and the thickness is based on the actual printing thickness, ranging from 80μm to 100μm. The printing resistive paste is a high-temperature ruthenium-based resistive paste with a sheet resistance of 220±10Ω / □ / mil. The traditional sintering method is tunnel furnace atmospheric sintering, with a peak temperature of 850±5℃ and a peak time of 9–11 minutes. The equipment is a piezoelectric jet valve composite triaxial 3D printing platform.

[0049] Computer-aided software was used to design a program for different spraying distances based on the size of the sprayed droplets. This program was then input into a three-axis 3D printing platform to deposit the droplets at designated locations on the substrate, completing the piezoelectric jetting resistor printing. After 2 minutes of room temperature drying and leveling, the substrate was heated with an infrared thermal lamp to maintain its shape. The infrared heating power was 200W–500W, with the power gradually increased to raise the temperature to 120–150℃ and held for 10–12 minutes. After the pre-sintering and curing step, the functionalized resistor paste was sintered using a defocused surface sintering process via continuous laser irradiation. Due to the relatively thick thickness of the printed resistor layer, multiple laser scans were required, with the laser power decreasing by 1.0 × 10⁴ W / cm² in each scan. 2 The scanning speed was increased by 0.5 mm / s, and the continuous laser power density was 5.0*10⁴~10*10⁴ W / cm². 2 The laser scanning speed is 1–3 mm / s, such as Figure 5 The figures from left to right show fusion ratios of 5%, 15%, 25%, 50%, 75%, and 95%. It can be seen that different droplet fusion ratios result in different shapes. It is foreseeable that different numbers of droplets of the same length fused in different ratios will change the thickness and morphology of the resulting resistive structure, ultimately changing the resistance value of the manufactured resistive structure and thus achieving resistance control.

[0050] Resistance values ​​were tested on laser-functionalized resistors, and curve fitting was performed between the resistors manufactured with different fusion ratios and the tested resistance values. Figure 6 As shown, the relationship between the droplet fusion ratio and the corresponding resistance value can be obtained. It can be seen that as the droplet fusion ratio increases, the resistance value of the manufactured resistive structure decreases according to a certain rule. Furthermore, as... Figure 7 As shown, the resistance value can be controlled by combining different droplet fusion states with different resistor shapes, such as linear, broken line, and "M" type, to design the resistor structure.

[0051] It should be noted that the above embodiments are merely illustrative and do not limit the scope of the present invention. Any variations and improvements made by those skilled in the art within the scope of this invention should be within the patent protection scope of this invention.

Claims

1. A non-contact in-situ manufacturing method for a conformal resistor, characterized in that, Includes the following steps: Step S1: Based on information including resistor pin gap, manufacturing range, and target resistance value, and by calculating the planar sheet resistance parameters of the material, select the material and conduct resistance testing to verify the piezoelectric jet droplet deposition area and thickness, and determine the resistor paste. Step S2: Based on step S1, a three-dimensional model of the curved device is obtained using computer-aided design software or 3D scanning technology. The obtained model is then used for piezoelectric jetting path planning, and for controlling the piezoelectric deposition droplets and conformal resistance of the curved surface. Specifically, for the piezoelectric deposition droplets of the complex curved surface, feedforward control is performed by adjusting the number of piezoelectric jetting dispensings and the fusion state between consecutive points. The droplet fusion ratio is 5% to 95%. The resistance value of the conformal resistance of the curved surface is controlled by changing the shape and thickness of the piezoelectric jetting printed resistor. Step S3: Fix the curved substrate to the printing platform, and use the piezoelectric jetting device to spray the resistive material from the nozzle according to the path and droplet fusion ratio set in step S2. The resulting jetting microdroplets are deposited non-contactly onto the designated position of the curved substrate to complete the curved conformal resistor printing. Step S4: The conformal resistor from step S3 is functionalized by in-situ infrared drying and in-situ laser sintering. Specifically, the in-situ infrared drying method involves irradiating the room-temperature-cured conformal resistor with a thermal infrared lamp at 100-150°C for 10-15 minutes. The in-situ laser sintering method involves directly irradiating the ruthenium-based resistor material with a continuous laser to sinter and solidify the conformal resistor, wherein the continuous laser power density is 0.5 × 10⁻⁶. 4 ~10×10 4 W / cm², laser scanning speed is 1~10mm / ; Step S5: Perform resistance value testing on the functionalized conformal resistor from step S4, and correct the conformal resistor using laser trimming. Step S6: The surface resistive protective layer is piezoelectrically jet-printed onto the functionalized conformal resistive surface modified in step S5 to complete the fabrication.

2. The method according to claim 1, characterized in that: The resistive slurry in step S1 is a high-temperature ruthenium-based slurry with a viscosity of 100~300 Pa·s.

3. The method according to claim 1, characterized in that: In step S3, the distance between the piezoelectric injection valve nozzle and the curved substrate surface is 2~6mm.

4. The method according to claim 1, characterized in that: In step S3, the parameters used by the piezoelectric jet valve include nozzle diameter, piezoelectric jet valve rise time, piezoelectric jet valve fall time, piezoelectric jet valve opening time, piezoelectric jet valve descent force, and piezoelectric jet valve delay time. Adjusting these parameters enables dispensing control of the piezoelectric jet device, thereby enabling control over the manufacturing of curved conformal resistive structures and patterns.

5. The method according to claim 1, characterized in that: Step S5 specifically refers to: clamping the conformal resistor onto the laser trimming device, using a laser to ablate the resistor body according to the initial resistance value to change the width of the resistor body, and adjusting the resistance value of the conformal resistor to its design value.

6. The method according to claim 1, characterized in that: In step S6, the protective layer material is polyimide (PI), glass enamel, or polyether ether ketone (PEEK). The protective layer is dried and cured using a curing oven with hot air circulation, heat radiation curing, or heat infrared lamp irradiation curing.

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