Semiconductor bridge transduction chip with double-side half-wrapped metal electrodes and preparation method thereof

Abstract

The invention discloses a semiconductor bridge transduction chip with double-side half-wrapped metal electrodes and a preparation method, and belongs to the technical field of electric initiating explosive devices. The semiconductor bridge transduction chip comprises a ceramic substrate layer, an insulating layer is arranged on one side of the ceramic substrate layer, and a polycrystalline silicon functional layer is arranged on the side, away from the ceramic substrate layer, of the insulating layer; the chip further comprises semi-wrapping metal electrodes located on the two sides of the chip, one inner side of each metal electrode is attached to the side, away from the insulating layer, of the polycrystalline silicon functional layer, and the other inner side of each metal electrode is attached to the side, away from the insulating layer, of the ceramic substrate layer. The semiconductor bridge transduction chip can be directly welded with a printed circuit board through the metal electrodes on the two sides of the back face of the chip, and the traditional gold wire bonding welding step which is poor in mechanical performance, high in cost and large in process implementation difficulty is omitted.

Description

Technical Field

[0001] The invention relates to the technical field of electric ignition products, and in particular to a semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes and a preparation method thereof. Background Art

[0002] Initiators are disposable components or devices containing gunpowder or explosives, which are used to trigger combustion or explosion under external mechanical shock, thermal energy or electrical energy excitation. As the core part of initiators, the transducer plays the role of energy conversion. Its design purpose is to achieve the excitation of high-energy energetic agents with a small initial excitation energy. Semiconductor bridge transducer initiators use semiconductor resistor bridge film as the transducer chip. It has the outstanding advantages of low ignition energy, fast excitation speed and high safety. It has been widely used in high-tech fields such as weapon system ignition, ammunition trajectory correction and satellite attitude control.

[0003] The ignition mechanism of semiconductor bridge pyrotechnics is: when current passes through the polysilicon bridge area, Joule heat is generated. The temperature of the polysilicon bridge gradually rises through the accumulation of Joule heat. When it reaches a certain temperature, the polysilicon bridge will undergo a phase change from solid to liquid, and then from liquid to vapor. Silicon vapor is rapidly heated and ionized under the continuous input of current to form plasma. This high-temperature, high-pressure fluid quickly diffuses into the explosive, allowing the explosive to quickly reach the detonation temperature and ignite. At present, due to the poor metal adhesion of the silicon substrate, it is difficult for traditional semiconductor bridge chips based on silicon substrates to form metal electrode layers on the side and back of the chip through magnetron sputtering. Therefore, it is necessary to use gold wire bonding to achieve electrical connection between the surface electrodes of the semiconductor bridge chip and the printed circuit board or the electrode plug of the pyrotechnics. For example, Xiangtan University used gold wire bonding in its patent application CN113314470 "A self-destructive chip device packaging structure and method with integrated energetic semiconductor bridge" to achieve electrical connection between the energetic semiconductor bridge chip and the printed circuit board, and to achieve ignition of the semiconductor bridge chip through a control chip. Nanjing University of Science and Technology pointed out in its patent application CN201262533Y "Semiconductor resistor bridge electrode plug" that the assembly of the semiconductor bridge chip and the printed circuit board requires at least three steps of chip mounting, gold wire bonding, and bonding glue protection. However, the process cost of gold wire bonding is relatively high, and the mechanical strength of the gold wire formed by bonding is poor, and it often needs to be protected by silver glue. When stored for a long time, it is easy to cause the pyrotechnics to ignite by mistake or ignite failure, which seriously reduces the reliability of the semiconductor bridge pyrotechnics. Summary of the invention

[0004] In order to solve the problem that the existing technology needs to use gold wire bonding to achieve electrical connection between the upper surface electrode of the semiconductor bridge chip and the printed circuit board or the electrode plug of the pyrotechnic device, the present invention provides a semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes and a preparation method, which can utilize the excellent metal adhesion ability of the ceramic substrate and realize the preparation of the double-sided semi-wrapped metal electrodes of the chip through magnetron sputtering technology.

[0005] The technical solution adopted by the semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes and the preparation method of the present invention is:

[0006] A semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes is characterized in that it includes a ceramic base layer, an insulating layer is arranged on one side of the ceramic base layer, and a polysilicon functional layer is arranged on the side of the insulating layer away from the ceramic base layer, and also includes semi-wrapped metal electrodes located on both sides of the chip, one inner side of the metal electrode is bonded to the side of the polysilicon functional layer away from the insulating layer, and the other inner side of the metal electrode is bonded to the side of the ceramic base layer away from the insulating layer.

[0007] A further improvement of the above technical solution of the present invention is that the thickness of the ceramic base layer is 300-500 μm.

[0008] A further improvement of the above technical solution of the present invention is that the material of the insulating layer is SiO2, and the thickness of the insulating layer is 2 μm.

[0009] A further improvement of the above technical solution of the present invention is that: the thickness of the polysilicon functional layer is 2 μm.

[0010] A further improvement of the above technical solution of the present invention is that: the metal electrode comprises three materials, namely Ti, W and Au, and the thickness of the metal electrode is 1 μm.

[0011] A further improvement of the above technical solution of the present invention is that a double V-shaped semiconductor bridge region is formed at the central part of the polysilicon functional layer, and is combined with the metal electrode to form a semiconductor bridge energy conversion element functional region.

[0012] A further improvement of the above technical solution of the present invention is that: the length of the semiconductor bridge region is 80 μm, the width is 380 μm, the V-shaped angle is 90°, and the resistance is 1Ω.

[0013] A method for preparing a semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes, characterized in that: the method is used to prepare the above transducer chip, comprising the following steps:

[0014] S1, thermally oxidizing the upper surface of the polished and cleaned ceramic base layer to form an insulating layer, and depositing a layer of polycrystalline silicon on the insulating layer by chemical vapor deposition to form a polycrystalline silicon functional layer;

[0015] S2, phosphorus ion implantation is performed on the polysilicon functional layer, with a doping concentration of 10 20 Atom / cm 3 , and use positive photoresist to perform photolithography, masking, and etching on polysilicon to form a double V-shaped semiconductor bridge region of a preset size;

[0016] S3, using magnetron sputtering technology to prepare semi-wrapped metal electrodes including Ti, W and Au on both sides of the chip;

[0017] S4. Slice and metallize the edges of the prepared wafers, and perform a non-ignition safety test on the packaged chips to test the chip safety performance.

[0018] A further improvement of the above technical solution of the present invention is that in step S4, a non-ignition safety test of 1A / 1W / 5min is performed on the packaged chip.

[0019] Due to the adoption of the above technical solution, the technical effects achieved by the present invention are as follows:

[0020] The present invention uses a ceramic layer as a semiconductor bridge transducer chip substrate and utilizes the excellent metal adhesion ability of the ceramic substrate to realize the preparation of semi-wrapped metal electrodes on both sides of the chip through magnetron sputtering technology.

[0021] The present invention can realize direct welding with a printed circuit board through metal electrodes located on both sides of the back side of the chip, omitting the traditional gold wire bonding welding step with poor mechanical properties, high cost and greater process implementation difficulty, and significantly enhancing the mechanical strength of chip welding.

[0022] At the same time, since the mechanical processing strength and thermal conductivity of the ceramic substrate are much better than those of the silicon substrate, the ceramic substrate semiconductor bridge energy conversion element chip with double-sided semi-wrapped metal electrodes proposed in the present invention has better electrical safety performance, is easier to process and integrate, and is convenient for the preparation and large-scale production of highly insensitive miniaturized electric ignition products. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a cross-sectional view of a semiconductor bridge transducer chip with double-sided half-wrapped metal electrodes of the present invention;

[0024] Figure 2 A top view of a semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes according to the present invention;

[0025] Figure 3 It is a back view of the semiconductor bridge transducer chip with double-sided half-wrapped metal electrodes of the present invention;

[0026] Figure 4The schematic diagram of the double V-shaped semiconductor bridge region structure of the semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes of the present invention.

[0027] In the attached figure: 1. Ceramic base layer; 2. Insulating layer; 3. Polysilicon functional layer; 4. Metal electrode. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in combination with specific implementation methods and with reference to the accompanying drawings. In the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0029] The invention provides a semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes and a method for preparing the transducer chip.

[0030] Embodiment 1

[0031] The semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes in the present invention is specifically arranged with reference to Figure 1 , Figure 2 and Figure 3 It can be seen that the semiconductor bridge transducer chip includes a ceramic base layer 1 located inside, the thickness of the ceramic base layer 1 is 300-500μm, an insulating layer 2 is arranged above the ceramic base layer 1, the material of the insulating layer 2 is SiO2, and the thickness of the insulating layer 2 is about 2μm, and a polycrystalline silicon functional layer 3 is arranged above the insulating layer 2, and the thickness of the polycrystalline silicon functional layer 3 is about 2μm; the semiconductor bridge transducer chip in the present invention also includes semi-wrapped metal electrodes 4 located on the left and right sides of the outside of the chip, the metal electrode 4 includes three materials of Ti, W and Au, and the thickness of the metal electrode 4 is about 1μm, one inner side of the metal electrode 4 is in contact with the top of the polycrystalline silicon functional layer 3, and the other inner side of the metal electrode 4 is in contact with the back side of the ceramic base layer 1.

[0032] like Figure 4 As shown, a double V-shaped semiconductor bridge region is provided at the top center of the polysilicon functional layer 3 in the present invention. The length of the double V-shaped semiconductor bridge region is 80 μm, the width is 380 μm, the V-shaped angle is 90°, and the resistance is about 1Ω. At the same time, the double V-shaped semiconductor bridge region is combined with the metal electrode 4 to form a semiconductor bridge transducer functional region.

[0033] Since the Joule heat generated by the semiconductor bridge is proportional to the resistance of the bridge area, in order to obtain better ignition performance, a semiconductor bridge area with a resistance of 1Ω is selected. The relationship between the resistance of the semiconductor bridge area and the bridge length, bridge width, square resistance and angle can be expressed as:

[0034]

[0035] Where R s is the square resistance of the bridge area, θ is the semiconductor bridge angle, L is the bridge length, and W is the bridge width.

[0036] Embodiment 2

[0037] Embodiment 2 is the preparation method of embodiment 1, specifically comprising the following steps:

[0038] S1. Thermally oxidize the upper surface of the polished and cleaned ceramic base layer 1 to form an insulating layer 2, and deposit a layer of polysilicon with a thickness of about 2 μm on the insulating layer 2 by chemical vapor deposition to form a polysilicon functional layer 3.

[0039] S2, injecting a doping concentration of 10 20 Atom / cm 3 The polysilicon functional layer 3 is photolithographically processed, masked and etched with a positive photoresist to form a double V-shaped semiconductor bridge region of a preset size.

[0040] S3. Using magnetron sputtering technology, prepare semi-wrapped metal electrodes 4 including three materials of Ti, W and Au located on both sides of the chip.

[0041] S4. Slice and metallize the edges of the prepared wafers, and perform a 1A / 1W5min non-ignition safety test on the packaged chips to test the chip safety performance.

[0042] In the above embodiment, the present invention provides a semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes and a preparation method. In this embodiment, the chip substrate material is ceramic. Since the ceramic substrate has excellent metal adhesion ability, the preparation of the double-sided semi-wrapped metal electrodes of the chip can be achieved by magnetron sputtering technology. Furthermore, the metal electrodes on both sides of the back of the chip can be directly welded to the printed circuit board, omitting the traditional gold wire bonding welding steps with poor mechanical properties, high cost, and difficult process implementation, significantly reducing the wiring difficulty, providing greater flexibility for circuit design, and effectively reducing the overall package size. At the same time, the mechanical processing strength and thermal conductivity of the ceramic substrate are much better than those of the silicon substrate. Therefore, the ceramic substrate semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes proposed in the present invention has better electrical performance and is easier to process and integrate. The chip has metal electrodes with double-sided semi-wrapped structures, which can achieve patch-type welding, simple process, and low packaging cost. The patch-type packaging process means that the packaged semiconductor bridge energy conversion element chip does not need to consider the impact of external shocks, which improves stability and reliability, and significantly reduces the structural complexity and production cost of electric ignition products, providing technical support for the preparation and large-scale production of highly insensitive miniaturized electric ignition products.

[0043] The embodiments described above are merely descriptions of preferred implementation modes of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes, characterized in that: The chip comprises a ceramic base layer (1), an insulating layer (2) is arranged on one side of the ceramic base layer (1), a polysilicon functional layer (3) is arranged on the side of the insulating layer (2) away from the ceramic base layer (1), and also comprises semi-wrapped metal electrodes (4) located on both sides of the chip, one inner side of the metal electrode (4) is bonded to the side of the polysilicon functional layer (3) away from the insulating layer (2), and the other inner side of the metal electrode (4) is bonded to the side of the ceramic base layer (1) away from the insulating layer (2).

2. The semiconductor bridge transducer chip with double-sided half-wrapped metal electrodes according to claim 1, characterized in that: The thickness of the ceramic base layer (1) is 300-500 μm.

3. The semiconductor bridge transducer chip with double-sided half-wrapped metal electrodes according to claim 1, characterized in that: The material of the insulating layer (2) is SiO2, and the thickness of the insulating layer (2) is 2 μm.

4. The semiconductor bridge transducer chip with double-sided half-wrapped metal electrodes according to claim 1, characterized in that: The thickness of the polycrystalline silicon functional layer (3) is 2 μm.

5. The semiconductor bridge transducer chip with double-sided half-wrapped metal electrodes according to claim 1, characterized in that: The metal electrode (4) comprises three materials: Ti, W and Au, and the thickness of the metal electrode (4) is 1 μm.

6. The semiconductor bridge transducer chip with double-sided half-wrapped metal electrodes according to claim 1, characterized in that: The central part of the polysilicon functional layer (3) forms a double V-shaped semiconductor bridge region, and is combined with the metal electrode (4) to form a semiconductor bridge energy conversion element functional region.

7. The semiconductor bridge transducer chip with double-sided half-wrapped metal electrodes according to claim 6, characterized in that: The semiconductor bridge region has a length of 80 μm, a width of 380 μm, a V-shaped angle of 90°, and a resistance of 1Ω.

8. A method for preparing a semiconductor bridge transducer chip with double-sided semi-wrapped metal electrodes, characterized in that: The method for preparing the transducer chip according to any one of claims 1 to 7 comprises the following steps: S1, thermally oxidizing the upper surface of the polished and cleaned ceramic base layer (1) to form an insulating layer (2), and depositing a layer of polycrystalline silicon on the insulating layer (2) by chemical vapor deposition to form a polycrystalline silicon functional layer (3); S2, implanting phosphorus ions into the polysilicon functional layer (3) at a doping concentration of 10 20 Atom / cm 3 , and use positive photoresist to perform photolithography, masking, and etching on polysilicon to form a double V-shaped semiconductor bridge region of a preset size; S3, using magnetron sputtering technology to prepare semi-wrapped metal electrodes (4) including three materials of Ti, W and Au located on both sides of the chip; S4. Slice and metallize the edges of the prepared wafers, and perform a non-ignition safety test on the packaged chips to test the chip safety performance.

9. The method for preparing a semiconductor bridge transducer chip with double-sided half-wrapped metal electrodes according to claim 8, characterized in that: In step S4, a non-ignition safety test of 1A / 1W / 5min is performed on the packaged chip.

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