A highly insensitive composite energetic thin film transducer element

Abstract

The application provides a high-insensitive composite energetic thin film transducing element, and belongs to the technical field of initiating explosive devices.The high-insensitive composite energetic thin film transducing element is mainly composed of an energetic thin film, a metal bridge chip, a ceramic electrode plug and an NTC thermistor; the energetic thin film is composed of an Al film, a Cu film and a CuO film; and the Cu film is added between the Al film and the CuO film, so that the performance aging of the composite thin film can be inhibited, the flame power after long storage can be improved, and the storage time can be prolonged.The metal bridge chip and the NTC thermistor are connected in parallel, so that the high-insensitive requirement can be achieved, and the metal bridge chip and the NTC thermistor can reach 2A4W5min without firing.

Description

Technical Field

[0001] This invention relates to the field of pyrotechnics technology, and in particular to a highly insensitive composite energetic thin-film transducer. Background Technology

[0002] Explosives are a general term for disposable components and devices that contain explosives and, upon exposure to external stimuli, ignite or explode to perform mechanical work. Bridge-type expendable devices are the most widely used, and are further divided into wire-bridged and membrane-bridged types.

[0003] With the integration of bridge-type pyrotechnics and MEMS technology, bridge-type ignition bridges offer advantages such as mass production, miniaturization and integration, high safety, and low cost. Based on the materials used, bridge-type ignition bridges can be categorized into metal membrane bridges, semiconductor membrane bridges, and composite energetic thin-film bridges. Among these, composite energetic thin-film ignition bridges are a key research focus both domestically and internationally.

[0004] Composite energetic thin films refer to films composed of nanoscale particles embedded in a thin film material, or multilayer films with a single layer thickness on the nanometer scale arranged periodically along a direction perpendicular to the substrate, according to a certain thickness (usually satisfying a certain chemical reaction stoichiometry). The thickness of a single periodic film ranges from a few nanometers to hundreds of nanometers, the total number of periods ranges from several to hundreds, and the total thickness of the multilayer films can reach several micrometers to tens of micrometers. Composite energetic thin films are divided into chemically reactive multilayer films (such as Al / CuO, Al / MoO3, Al / Fe2O3, etc.) and alloying reactive multilayer films (such as Al / Ti, Al / Ni, B / Ti, etc.), which release heat through redox reactions and alloying reactions, respectively. Both types of composite energetic thin films can undergo vigorous exothermic reactions under relatively low energy input, accompanied by plasma formation, and can exhibit self-propagating reactions. Furthermore, currently research on near-saturated composite reactive thin films is usually based on Al systems, which are prone to oxidation, not resistant to high temperatures, unstable, and release relatively low energy.

[0005] Therefore, how to obtain a highly insensitive composite energetic thin-film transducer is a technical problem that needs to be solved. Summary of the Invention

[0006] The purpose of this invention is to provide a highly insensitive composite energetic thin film transducer to solve the above-mentioned technical problems.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a high-passivity composite energetic thin-film transducer, which mainly consists of an energetic thin film, a metal bridge chip, a ceramic electrode plug, and an NTC thermistor; the energetic thin film is composed of an Al film, a Cu film, and a CuO film. The metal bridge chip comprises, from bottom to top, an Al2O3 ceramic substrate layer, a photoresist layer, a Ni-Cr thin film layer, and an Au pad layer; The energetic thin film is sputtered onto the Au pad layer.

[0008] Furthermore, the ceramic electrode plug is cylindrical, with a groove on both the upper and lower surfaces. The groove on the upper surface is used to encapsulate the metal bridge chip, and the groove on the lower surface is used to encapsulate the NTC thermistor.

[0009] Furthermore, the ceramic electrode plug is formed by sintering a ceramic shell and an electrode.

[0010] Furthermore, the Au pad layer has a groove in the middle, which together with the Ni-Cr thin film layer forms a metal bridge area. The metal bridge area is double V-shaped with an angle of 90°. The dimensions of the metal bridge area are: length 455~465μm, width 225~230μm, and thickness 0.80~0.85μm.

[0011] Furthermore, the metal bridge chip is connected to the electrode via a silicon-aluminum wire, the surface of which is coated with conductive silver paste.

[0012] Furthermore, the NTC thermistor is attached to the groove on the lower surface of the ceramic electrode plug by epoxy resin adhesive; The NTC thermistor is connected to the electrode via solder pads.

[0013] Furthermore, in the energetic thin film, a Cu film is disposed as a barrier layer between the Al film and the CuO film; The Al film has a thickness of 80-100 nm, the Cu film has a thickness of 8-12 nm, and the CuO film has a thickness of 150-200 nm. The modulation period of the energetic thin film is 238~312nm, and the number of periods is 10.

[0014] Furthermore, in the metal bridge chip, the thickness of the Al2O3 ceramic substrate layer is 500μm, the thickness of the photoresist layer is 1~2μm, the thickness of the Ni-Cr thin film layer is 0.80~0.85μm, and the thickness of the Au pad layer is 1~3μm.

[0015] Furthermore, the depth of the groove on the upper surface of the ceramic electrode plug is 0.5~1mm, and the depth of the groove on the lower surface is 0.5~1mm.

[0016] The beneficial effects of this invention are: 1. The composite energetic thin film metal bridge provided by the present invention, compared with the traditional metal bridge, replaces the first-stage artificial detonator coating formed by magnetron sputtering deposition of the composite energetic thin film layer, which is more controllable and safer.

[0017] 2. By designing the modulation period and modulation ratio, the output energy of the transducer element can achieve reliable ignition with a 1mm gap and a maximum flame height of 5mm.

[0018] 3. Adding a Cu film between the Al film and the CuO film can inhibit the performance aging of the composite film, improve the flame power after long-term storage, and extend the storage time.

[0019] 4. A parallel NTC thermistor in the bridge area can achieve 2A 4W for 5 minutes without sparking, meeting the high insensitivity requirement. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the high-passivity composite energetic thin film transducer structure obtained by the present invention; Figure 2 This is a schematic diagram of the structure of the metal bridge chip of the present invention; Figure 3 This is a top view of the metal bridge chip of the present invention; Among them, 1-energized thin film; 2-metal bridge chip; 3-conductive silver paste; 4-ceramic electrode plug; 5-epoxy resin adhesive; 6-NTC thermistor; 7-tin sheet; 8-electrode; 9-Au pad layer; 10-Ni-Cr thin film layer; 11-photoresist layer; 12-Al2O3 ceramic substrate layer. Detailed Implementation

[0021] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] like Figure 1-3 As shown, a high-passivity composite energetic thin-film transducer mainly consists of an energetic thin film 1, a metal bridge chip 2, a ceramic electrode plug 4, and an NTC thermistor 6; the energetic thin film 1 is composed of an Al film, a Cu film, and a CuO film. The metal bridge chip 2 comprises, from bottom to top, an Al2O3 ceramic substrate layer 12, a photoresist layer 11, a Ni-Cr thin film layer 10, and an Au pad layer 9. The energetic thin film 1 is sputtered onto the Au pad layer 9.

[0023] Specifically, an insulating layer is provided between the energetic thin film 1 and the Au pad layer 9, and the insulating layer is a CuO layer with a thickness of 300 nm.

[0024] Specifically, the ceramic electrode plug 4 is cylindrical, and a groove is formed on both the upper and lower surfaces of the cylinder. The groove on the upper surface is used to encapsulate the metal bridge chip 2, and the groove on the lower surface is used to encapsulate the NTC thermistor 6.

[0025] Specifically, the ceramic electrode plug 4 is formed by sintering a ceramic shell and an electrode 8, and the ceramic shell is treated with metallized through holes.

[0026] Specifically, the Au pad layer 9 has a groove in the middle, which together with the Ni-Cr thin film layer 10 forms a metal bridge region, as shown in the figure. Figure 3 The shaded area shows a double V-shape with an angle of 90°. The dimensions of the metal bridge region are: length 455~465μm, width 225~230μm, and thickness 0.80~0.85μm; preferably, the dimensions of the metal bridge region are: length 460μm, width 230μm, and thickness 0.83μm.

[0027] Specifically, the metal bridge chip 2 is connected to the electrode 8 via a silicon-aluminum wire, and the surface of the silicon-aluminum wire is coated with conductive silver paste 3.

[0028] Specifically, the NTC thermistor 6 is attached to the groove on the lower surface of the ceramic electrode plug 4 by epoxy resin adhesive 5; The NTC thermistor 6 is connected to the electrode 8 via solder sheet 7, so that the NTC thermistor 6 and the metal bridge area form a parallel circuit.

[0029] Specifically, in the energetic thin film 1, the Cu film is disposed as a barrier layer between the Al film and the CuO film; The Al film has a thickness of 80-100 nm, the Cu film has a thickness of 8-12 nm, and the CuO film has a thickness of 150-200 nm; preferably, the Al film has a thickness of 90 nm, the Cu film has a thickness of 10 nm, and the CuO film has a thickness of 180 nm.

[0030] Specifically, the modulation period of the energetic thin film is 238~312nm, preferably 280nm; the number of periods is 10, and the total thickness is 2.8μm.

[0031] Specifically, in the metal bridge chip 2, the Al2O3 ceramic substrate layer 12 has a thickness of 500 μm, the photoresist layer 11 has a thickness of 1~2 μm, preferably 2 μm; the Ni-Cr thin film layer 10 has a thickness of 0.80~0.85 μm, preferably 0.83 μm; and the Au pad layer 9 has a thickness of 1~3 μm, preferably 2 μm.

[0032] Specifically, the depth of the groove on the upper surface of the ceramic electrode plug 4 is 0.5~1mm, preferably 0.5mm; the depth of the groove on the lower surface is 0.5~1mm, preferably 0.5mm. Example 1

[0033] The preparation method of the above-mentioned highly insensitive composite energetic thin film transducer includes the following steps: Step 1: Prepare a nickel-chromium bridge thin film using magnetron sputtering. First, a 1μm photoresist layer 11 is coated on a 500μm thick, 95% Al2O3 ceramic substrate 12 using a spin coater. Then, a 0.83μm Ni-Cr thin film layer 10 is sputtered using magnetron sputtering.

[0034] Step 2: The bridge region is masked using a masking method. A 2μm Au pad layer 9 is sputtered onto the Ni-Cr thin film layer 10. Finally, the shape of the pads and the shape of the Ni-Cr metal bridge region are obtained through a peeling process. Finally, it is cut into individual Ni-Cr metal bridge chips 2.

[0035] Step 3: In order to prevent the Al layer in the energetic thin film 1 from short-circuiting the nickel-chromium metal bridge, a 300 nm CuO layer is first sputtered on the surface of the nickel-chromium metal bridge as an insulating layer. Then, a 90 nm Al layer, a 10 nm Cu layer, and a 180 nm CuO layer are alternately sputtered on it to form an Al / Cu / CuO composite energetic thin film.

[0036] Step 4: Encapsulate the metal bridge chip 2 on the ceramic electrode plug 4. A groove with a depth of 0.5 mm is machined between the two electrodes of the ceramic electrode plug 4, and the metal bridge chip 2 is placed inside. Using ultrasonic welding, silicon-aluminum wire is used to connect the pads of the metal bridge chip 2 to the electrode 8. To improve the strength of the welding wire, conductive silver paste 3 is used to wrap the welding wire, and it is then heated at 150°C for 1 hour.

[0037] Step 5: Dig a 0.5mm deep groove at the bottom of the ceramic electrode plug 4 to encapsulate the NTC thermistor 6. The encapsulation process is as follows: first, use epoxy resin 5 to stick the NTC thermistor 6 into the groove, use solder sheet 7 to connect the NTC thermistor 6 and the electrode 8, and then encapsulate and cure. Example 2

[0038] The preparation method of the above-mentioned highly insensitive composite energetic thin film transducer includes the following steps: Step 1: Prepare a nickel-chromium bridge thin film using magnetron sputtering. First, a 2μm photoresist layer 11 is coated on a 500μm thick, 95% Al2O3 ceramic substrate 12 using a spin coater. Then, a 0.85μm Ni-Cr thin film layer 10 is sputtered using magnetron sputtering.

[0039] Step 2: The bridge area is masked using a masking method. A 1μm Au pad layer 9 is sputtered onto the Ni-Cr thin film layer 10. Finally, the shape of the pads and the shape of the Ni-Cr metal bridge area are obtained through a peeling process. Finally, it is cut into individual Ni-Cr metal bridge chips 2.

[0040] Step 3: In order to prevent the Al layer in the energetic thin film 1 from short-circuiting the nickel-chromium metal bridge, a 300 nm CuO layer is first sputtered on the surface of the nickel-chromium metal bridge as an insulating layer. Then, an 80 nm Al layer, a 12 nm Cu layer, and a 200 nm CuO layer are alternately sputtered on it to form an Al / Cu / CuO composite energetic thin film.

[0041] Step 4: Encapsulate the metal bridge chip 2 on the ceramic electrode plug 4. A groove with a depth of 0.5 mm is machined between the two electrodes of the ceramic electrode plug 4, and the metal bridge chip 2 is placed inside. Using ultrasonic welding, silicon-aluminum wire is used to connect the pads of the metal bridge chip 2 to the electrode 8. To improve the strength of the welding wire, conductive silver paste 3 is used to wrap the welding wire, and it is then heated at 150°C for 1 hour.

[0042] Step 5: Dig a 0.5mm deep groove at the bottom of the ceramic electrode plug 4 to encapsulate the NTC thermistor 6. The encapsulation process is as follows: first, use epoxy resin 5 to stick the NTC thermistor 6 into the groove, use solder sheet 7 to connect the NTC thermistor 6 and the electrode 8, and then encapsulate and cure.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A highly insensitive composite energetic thin-film transducer, characterized in that, It is mainly composed of an energetic thin film, a metal bridge chip, a ceramic electrode plug and an NTC thermistor; the energetic thin film is composed of Al film, Cu film and CuO film composite; The metal bridge chip comprises, from bottom to top, an Al2O3 ceramic substrate layer, a photoresist layer, a Ni-Cr thin film layer, and an Au pad layer; The energetic thin film is sputtered onto the Au pad layer; In the energetic thin film, the Cu film is disposed as a barrier layer between the Al film and the CuO film; The Al film has a thickness of 80-100 nm, the Cu film has a thickness of 8-12 nm, and the CuO film has a thickness of 150-200 nm. The modulation period of the energetic thin film is 238~312nm, and the number of periods is 10; The Au pad layer has a groove in the middle, which together with the Ni-Cr thin film layer forms a metal bridge area. The metal bridge area is double V-shaped with an angle of 90°. The dimensions of the metal bridge area are: length 455~465μm, width 225~230μm, and thickness 0.80~0.85μm.

2. The high-passivity composite energetic thin-film transducer element according to claim 1, characterized in that, The ceramic electrode plug is cylindrical, with a groove on both the upper and lower surfaces. The groove on the upper surface is used to encapsulate the metal bridge chip, and the groove on the lower surface is used to encapsulate the NTC thermistor.

3. The high-passivity composite energetic thin-film transducer element according to claim 1 or 2, characterized in that, The ceramic electrode plug is formed by sintering a ceramic shell and an electrode.

4. The high-passivity composite energetic thin-film transducer element according to claim 3, characterized in that, The metal bridge chip is connected to the electrode via a silicon-aluminum wire, the surface of which is coated with conductive silver paste.

5. The high-passivity composite energetic thin-film transducer element according to claim 4, characterized in that, The NTC thermistor is attached to the groove on the lower surface of the ceramic electrode plug by epoxy resin adhesive; The NTC thermistor is connected to the electrode via solder pads.

6. The high-passivity composite energetic thin-film transducer element according to claim 1, characterized in that, In the metal bridge chip, the Al2O3 ceramic substrate layer has a thickness of 500 μm, the photoresist layer has a thickness of 1~2 μm, the Ni-Cr thin film layer has a thickness of 0.80~0.85 μm, and the Au pad layer has a thickness of 1~3 μm.

7. The high-passivity composite energetic thin-film transducer element according to claim 2, characterized in that, The depth of the groove on the upper surface of the ceramic electrode plug is 0.5~1mm, and the depth of the groove on the lower surface is 0.5~1mm.

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