A design integration method of bridge membrane chip transducer element for safe ignition

Abstract

The application provides a safe ignition transducing element chip design parameter determination method, and belongs to the field of electric heat ignition devices for electric detonators. The transducing element chip comprises a bridge region, the bridge region has a V-shaped structure, and the method comprises the following steps: setting a bridge region resistance value according to a preset fusing current of the bridge region; setting an angle of a V-shaped angle in the V-shaped structure according to a preset explosion time of the bridge region under a preset explosion current input; determining a length-width ratio of the bridge region according to the angle of the V-shaped angle and the bridge region resistance value; setting a bridge length according to the preset critical explosion current, and determining a bridge width according to the length-width ratio of the bridge region and the bridge length. The method can design the transducing element chip meeting the safe ignition requirement, and can reduce the chip design difficulty and use cost under the premise of ensuring the size precision of the bridge shape.

Description

Technical Field

[0001] This invention belongs to the field of electrothermal ignition devices for electro-explosive products, and specifically relates to a method for determining the design parameters of a transducer chip for safe ignition. Background Technology

[0002] As the primary component in electro-ignition devices, the electrothermal transducer plays a crucial role in the safe and reliable ignition of electro-ignition devices such as electric detonators, electric igniters, and electric primers. Currently, most safe ignition electro-ignition devices use semiconductor bridge chips and bridge strips cut from nickel-chromium alloy foil. Semiconductor bridge chips have poor mechanical properties and weak adaptability to environmental temperatures, while nickel-chromium alloy bridge strips have advantages such as a wide operating temperature range, high compressive and shear strength, and good high and low temperature recovery performance. However, bridge strips processed by mechanical cutting methods have poor dimensional accuracy and low yield.

[0003] The current stability of a bridged diaphragm chip refers to the fact that the bridge region does not melt during long-pulse (≥5 min) constant current heating, and the resistance remains consistent before and after heating. The current stability of the bridged diaphragm chip is fundamental to the current safety of pyrotechnics, as well as their electromagnetic radiation safety and electrostatic discharge safety. Therefore, current stability design is the primary issue in bridged diaphragm chip design. However, current technology lacks methods for designing the current stability of bridged diaphragm chips, thus making it impossible to obtain bridged diaphragm chips that meet safe ignition requirements. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art and provide a method for determining the design parameters of a transducer chip for safe ignition. The method involves setting the resistance value of the bridge region based on the preset fusing current of the bridge region, setting the angle of the V-shaped angle in the V-shaped structure based on the preset burst time of the bridge region under the preset burst current input, determining the aspect ratio of the bridge region based on the angle of the V-shaped angle and the resistance value of the bridge region, setting the bridge length based on the preset critical burst current, and determining the bridge width based on the aspect ratio of the bridge region and the bridge length. In this way, a transducer chip that meets the requirements for safe ignition can be designed.

[0005] This invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a method for determining the design parameters of a transducer chip for safe ignition, the transducer chip including a bridge region having a V-shaped structure, the method comprising:

[0007] The bridge resistance value is set according to the preset fuse current of the bridge area;

[0008] Under a preset burst current input, the angle of the V-shaped angle in the V-shaped structure is set according to the preset burst time of the bridge region;

[0009] The aspect ratio of the bridge region is determined based on the angle of the V-shaped angle and the resistance value of the bridge region.

[0010] The bridge length is set according to the preset critical burst current, and the bridge width is determined according to the aspect ratio of the bridge region and the bridge length.

[0011] A further improvement of the present invention is that:

[0012] Based on the preset fusing current of the bridge section, the bridge resistance value of the bridge section is set according to the following formula:

[0013]

[0014] Among them, R b0 For the bridge region at room temperature, T bd Where T is the critical melting temperature, T0 is the initial temperature, and I is the critical melting temperature. d χ is the critical fusing current of the bridge region, where χ is the heat dissipation coefficient of the bridge diaphragm chip and specific integrated components to the environment, and S is the thermal conductivity coefficient. c This represents the heat dissipation area.

[0015] A further improvement of the present invention is that:

[0016] When the transducer chip is a short-pulse constant current input, under a preset burst current input, the angle of the V-shaped angle in the V-shaped structure is set according to the preset burst time of the bridge region based on the following formula:

[0017]

[0018] in, ρ is the heat capacity of the bridge material, δ is the thickness of the bridge region, and ρ is the heat capacity of the bridge b For the density of the bridge material, The burst temperature, The initial temperature of the bridge area. R is the narrowest width ratio, η is the bridge region self-retaining thermal coefficient under short pulse constant current input, and R is the narrowest width ratio. s For the structural resistance of the bridge area materials, I e The preset burst current is given, ω is the aspect ratio of the bridge region, and t is the value of the burst current. e The preset burst time is given by l, where l is the bridge length.

[0019] A further improvement of the present invention is that:

[0020] The aspect ratio of the bridge region is determined based on the angle of the V-shaped angle and the resistance value of the bridge region using the following formula:

[0021]

[0022] in, R is the aspect ratio of the bridge area. b0 R is the resistance at room temperature in the bridge region. s Let θ be the sheet resistance of the bridge material, and θ be the angle of the V-shaped angle.

[0023] A further improvement of the present invention is that the bridge length of the bridge region is set according to the preset critical burst current based on the following formula:

[0024]

[0025] Among them, I ec To preset the critical burst current, t ec The burst time used for the preset critical burst current.

[0026] A further improvement of the present invention is that the bridge region room temperature resistor R b0 The range of values ​​for is: 0.6Ω ≤ R b0 ≤1.1Ω.

[0027] A further improvement of the present invention is that the angle θ of the V-shaped angle is in the range of 90º≤θ≤180º, and the bridge length l of the bridge area is in the range of 60μm≤l≤210μm.

[0028] A further improvement of the present invention is that the transducer chip further includes H-shaped pads disposed on both sides of the bridge region, the transducer chip is disposed on the substrate, and the distance between the outer circle of the H-shaped pad and the boundary of the substrate is greater than 1 mm.

[0029] In a second aspect, the present invention provides a transducer chip for a pyrotechnic device, wherein the design parameters of the transducer chip are obtained by the transducer chip design parameter determination method for safe ignition described in any one of the first aspects above.

[0030] A third aspect of the present invention provides a bridged membrane transducer comprising the transducer chip and a substrate as described in the second aspect, wherein the transducer chip is fixed on the substrate.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows: the resistance value of the bridge region is set according to the preset fusing current of the bridge region; under the preset burst current input, the angle of the V-shaped angle in the V-shaped structure is set according to the preset burst time of the bridge region; the aspect ratio of the bridge region is determined according to the angle of the V-shaped angle and the resistance value of the bridge region; the bridge length is set according to the preset critical burst current; and the bridge width is determined according to the aspect ratio of the bridge region and the bridge length. Thus, a transducer chip that meets the requirements of safe ignition can be designed, and the chip design difficulty and usage cost can be reduced while ensuring the dimensional accuracy of the bridge shape. Attached Figure Description

[0032] The above and other objects, features, and advantages of the present invention will become more apparent from the more detailed description of the embodiments of the invention in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0033] Figure 1 This is a schematic diagram of the structure of the transducer chip in some embodiments of the present invention;

[0034] Figure 2a for Figure 1 A schematic diagram of the bridge region of the intermediate power converter chip;

[0035] Figure 2b for Figure 1 A schematic diagram of the pad structure of the mid-stage switching element chip;

[0036] Figure 3 This is a flowchart illustrating a method for determining the design parameters of a transducer chip for safe ignition, according to some embodiments of the present invention.

[0037] Figure 4a This is a schematic diagram of the transducer structure in one embodiment of the present invention;

[0038] Figure 4b for Figure 4a The bottom view of the transducer shown;

[0039] Figure 4c for Figure 4a A top view of the transducer shown;

[0040] Figure 5 This is a schematic diagram of the bridge region numbering of a bridge diaphragm chip for safe ignition in one embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram showing the shape and dimensions of a bridge membrane chip in one embodiment of the present invention;

[0042] Figure 7 This is a schematic diagram of the bridge membrane chip numbering rule in one embodiment of the present invention;

[0043] Figure 8 This is a flowchart illustrating the fabrication process of a bridge membrane chip according to one embodiment of the present invention;

[0044] Figure 9 This is an integrated process flow diagram of a bridge diaphragm transducer chip according to one embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of the present invention, and not all of the embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein. Based on the embodiments of the present invention described herein, all other embodiments obtained by those skilled in the art without inventive effort should fall within the protection scope of the present invention.

[0046] Since there is a lack of current stability design methods for bridge diaphragm chips in the existing technology, it is impossible to obtain bridge diaphragm chips that meet the requirements for safe ignition. Based on this, the present invention proposes a method for determining the design parameters of a transducer chip for safe ignition. The present invention will be further described in detail below with reference to the accompanying drawings.

[0047] First, refer to Figure 1 , Figure 2a and Figure 2b To describe the transducer chip of some embodiments of the present invention

[0048] like Figure 1 As shown, the transducer chip in this invention includes at least a bridge region, a pad, and a substrate, wherein the bridge region is an electrothermal region, the pad is a heat dissipation region, and the substrate is a chip support.

[0049] The bridge region has a V-shaped structure. Specifically, the transducer chip can be a bridge membrane chip with a "V"-shaped bridge region structure, so that the bridge membrane chip can focus electrothermal energy to the center of the bridge membrane chip. The maximum current density of the bridge membrane chip can be controlled by the bridge region pattern design, thereby controlling the energy focusing effect of the bridge membrane chip.

[0050] To meet the process requirements of chip dicing, the pads are designed in an "H" shape. For the structure and parameters of the bridge area and pads, please refer to [link / reference needed]. Figure 2a and Figure 2b .

[0051] like Figure 2a As shown, the V-shaped bridge area includes the V-angle θ, bridge length l, bridge width w, and narrowest bridge width w. m Four geometric quantities are introduced. This invention introduces two dimensionless geometric quantities: the bridge length-to-width ratio ω and the narrowest width ratio ξ, and uses the bridge length l, length-to-width ratio ω, and narrowest width ratio ξ as graphical parameters characterizing the bridge area.

[0052] like Figure 2b As shown, the pads have an H-shaped structure. The length L and width W of the H-shaped structure are used as graphical parameters to characterize the pads.

[0053] Ignoring the resistance of the substrate electrode and the pads of the bridge diaphragm chip, the transducer element resistance of the bridge diaphragm chip is the same as the bridge region resistance. The calculation formulas for the bridge region resistance, bridge region quality, and bridge region graphic parameters are shown in Equation (1).

[0054] (1)

[0055] Where δ is the bridge region thickness, R b0 R is the resistance at room temperature in the bridge region. s For the sheet resistance of the bridge material, ρ b The density of the bridge material is m. b For the quality of the bridge area.

[0056] The equation set shown in equation (1) above indicates that when the bridge thickness is constant, the bridge resistance is only related to two graphic parameters: the length-to-width ratio and the narrowest width ratio (or V-angle), while the bridge quality is also related to the bridge length.

[0057] Next, refer to Figure 3 This invention describes a method for determining the design parameters of a transducer chip for safe ignition, according to some embodiments of the present invention.

[0058] like Figure 3 As shown, the method includes the following steps S10-S40.

[0059] Step S10: Set the bridge resistance value according to the preset fuse current of the bridge region.

[0060] In this invention, the bridge resistance value refers to the room temperature resistance value of the bridge region. Addressing the lack of design methods for the current stability of bridge diaphragm chips, this invention... As initial conditions, the bridge region electrothermal balance equation under long pulse low amplitude constant current input (safe mode) was established as shown in equation (2), and an analytical solution was obtained.

[0061] (2)

[0062] in, For the heat capacity of the bridge material, T b Let t be the bridge temperature, I be the current, α be the temperature coefficient of resistance, χ be the heat dissipation coefficient of the bridge diaphragm chip and specific integrated components to the environment, and S be the current. c This refers to the heat dissipation area of ​​the integrated component.

[0063] Equation (2) is used to obtain equation (3) for the bridge region temperature rise under long pulse low amplitude constant current input:

[0064] (3)

[0065] For commonly used bridge diaphragm chip materials, such as polycrystalline silicon, tantalum nitride, and nickel-chromium alloys; the α value is in

[0066] 10 -4 The value is on the order of Ω / K, within the equilibrium temperature range of bridge-zone electric heating. Much larger Then equation (3) can be simplified to equation (4):

[0067] (4)

[0068] Under conditions of slowly increasing input current, the time for the bridge region to reach thermal equilibrium is typically greater than [time value missing]. More than three times that of the previous value, the relationship between temperature and current shown in equation (4) can be simplified to the following equation (5):

[0069] (5)

[0070] When the bridge temperature is below the critical melting temperature, the bridge region undergoes reversible thermal expansion and can spontaneously recover to near its original structure and resistance value after cooling; when the bridge temperature rises to the critical melting temperature T... bd At that time, the bridge structure became unstable and the fuse broke. The critical fusing current I in the bridge area... d The expression is as follows (6):

[0071] (6)

[0072] Equation (6) shows that when the heat dissipation area remains constant, the larger the bridge resistance, the lower the fusing current, and the worse the current stability of the bridge diaphragm chip. Therefore, in this invention, the bridge resistance is used as the main factor determining the current stability of the bridge diaphragm chip to determine the relevant parameters of the bridge region. The basis is sufficient, the process is reasonable, the calculation method is complete, and the final experiment verifies that the method is correct and effective.

[0073] Step S20: Under the preset burst current input, set the angle of the V-shaped angle in the V-shaped structure according to the preset burst time of the bridge zone.

[0074] Bridge zone eruption refers to a phase transition phenomenon that occurs when the bridge zone electric heating temperature reaches the bridge zone eruption temperature. It is the physical mechanism that ignites pyrotechnics. Therefore, the input energy required for bridge zone eruption is also the ignition energy of the bridge diaphragm pyrotechnic. The lower the eruption energy, the lower the required system power supply energy, and the higher the energy margin for ignition of the pyrotechnic with limited energy input, thus improving ignition reliability.

[0075] The electrothermal energy-concentrating effect refers to the use of a V-shaped bridge region to concentrate electrothermal energy at the center of the bridge region, thereby reducing the burst time of the bridge diaphragm chip. In this invention, to characterize and calculate the electrothermal energy-concentrating effect, a self-retaining heat coefficient η is innovatively introduced, simplifying the heat loss term in the bridge region electrothermal equation and ignoring the change in bridge region resistance with temperature. This yields the theoretical relationship between the critical burst current and burst time of the bridge diaphragm chip and the bridge region resistance under short-pulse constant current input (operating mode), thereby reducing the design difficulty of the bridge region parameters.

[0076] Specifically, the bridge region's self-retaining heat coefficient is determined based on the heat loss term in the bridge region's electrothermal equation, such as heat transfer from the bridge region to the substrate and matrix, convective heat transfer with air, and radiative heat transfer, thus the initial conditions are... At that time, the electrothermal equation based on the bridge zone's self-retained heat coefficient can be simplified to:

[0077] (7)

[0078] Among them, c b Let η be the heat capacity of the bridge material, I be the input current, and η be the self-retaining heat coefficient of the bridge.

[0079] Integrating the equation shown in equation (7) above, we obtain the equation for the electrothermal heating of the bridge region:

[0080] (8)

[0081] Therefore, it can be seen that the heating rate of the bridge diaphragm chip with short-pulse constant current input is directly proportional to the bridge resistance-to-mass ratio.

[0082] At the preset burst current I e Input below, assuming t=t e At that moment, the bridge area heated up to its burst temperature T. be , then t e Defined as the bridge burst time, the burst time t can be obtained according to equation (8). e Relationship with the bridge resistance-to-mass ratio:

[0083] (9)

[0084] Among them, I e This is the burst current.

[0085] Substituting the relationship between the resistance-to-mass ratio and the bridge parameters in equation (1) into equation (9), we obtain the relationship between the burst time and the bridge parameters:

[0086] (10)

[0087] As can be seen from equation (10), when the bridge length is constant, the length-to-width ratio and V-angle of the bridge area are the main factors affecting the burst time. However, the change in the length-to-width ratio is much smaller than the change in the minimum width ratio. According to the expression for the minimum width ratio in equation (1), the smaller the V-angle, the smaller the narrowest width ratio, the shorter the burst time, and the stronger the energy focusing effect.

[0088] According to the minimum width ratio expression in equation (1), the smaller the V-angle, the smaller the narrowest width ratio, the shorter the burst time, and the stronger the energy focusing effect. Therefore, when setting the angle of the V-angle in the V-structure, the bridge area V-angle can be set to multiple angles according to the burst time, and the multiple angles are equally spaced.

[0089] Step S30: Determine the aspect ratio of the bridge region based on the angle of the V-shaped angle and the resistance value of the bridge region.

[0090] Based on the expressions for the bridge resistance and bridge graphic parameters in the equation set shown in equation (1), the design calculation formula for the bridge aspect ratio ω can be obtained as follows:

[0091] (11)

[0092] in, The aspect ratio of the bridge area, For the structural resistance of materials in the bridge area.

[0093] Substituting the V-angle angle and bridge resistance value obtained in the above steps into equation (11), the aspect ratio of the bridge region can be calculated.

[0094] Step S40: Set the bridge length according to the preset critical burst current, and determine the bridge width according to the length-to-width ratio of the bridge area and the bridge length.

[0095] In this invention, an outbreak occurring at a given moment is called a critical outbreak.

[0096] Assume the bridged membrane chip requires that at a given time (t=t... ec If an explosion occurs, the explosion current (I) e =I ec The critical burst current is defined as . From equation (9), the relationship between the critical burst current and the bridge parameters can be obtained:

[0097] (12)

[0098] As can be seen from equation (12), once the V-angle and aspect ratio are determined, the critical burst current is proportional to the bridge length.

[0099] After setting the bridge length, the bridge width can be determined based on the length-to-width ratio of the bridge area and the bridge length.

[0100] The present invention provides a method for determining the design parameters of a transducer chip for safe ignition. This method solves the problem of high chip design difficulty while ensuring the dimensional accuracy of the bridge structure, reduces the cost of chip use, and can effectively determine the relevant design parameters of the bridge diaphragm chip that meet the requirements for safe ignition.

[0101] In some embodiments of this application, the bridge region room temperature resistance R b0 The value range is 0.6Ω ≤ R b0 ≤1.1Ω.

[0102] As can be seen from the above equation (6), the critical fusing current of the bridge region is inversely proportional to the resistance of the bridge region. The smaller the resistance of the bridge region, the higher the critical fusing current, and the better the current stability of the bridge diaphragm chip.

[0103] Since the electrothermal energy of a bridge diaphragm chip is directly related to its resistance, and considering both current stability and electrothermal burst characteristics, the resistance value of a bridge diaphragm chip can be classified into two types:

[0104] Low-resistance bridge film chip (S-type): R b0 =0.67±0.07Ω, current stability not less than 2.0A 5min, and safe current with specific reagents not less than 1.5A 5min;

[0105] Standard resistor bridge film chip (M type): R b0=1.00±0.10Ω, current stability not less than 1.5A 2.25W 5min, and safe current with specific reagents not less than 1A 1W 5min.

[0106] In some embodiments of this application, the angle θ of the V-shaped angle ranges from 90º≤θ≤180º.

[0107] Specifically, according to equation (11), based on the bridge area electrothermal energy concentration effect, the V-shaped angle of the bridge area can be divided into four types, starting from 180° and spaced 30° apart.

[0108] Type 0: θ=180°, rectangular bridge membrane chip, no energy focusing effect;

[0109] Type 1: θ=150°, possesses a certain energy-concentrating effect;

[0110] Type 2: θ=120°, exhibiting a significant energy-concentrating effect;

[0111] Type 3: θ=90°, with a strong energy focusing effect.

[0112] In some embodiments of this application, the bridge length l of the bridge area is in the range of 60μm≤l≤210μm.

[0113] Specifically, based on the above formula (13), taking into account the chip processing cost, the bridge length starts from 60μm and is divided into 6 levels with an interval of 30μm.

[0114] Level 1, l=60μm; First bridge length in the low-resistance bridge region;

[0115] Level 2, l=90μm; Second bridge length in the low resistance bridge region, first bridge length in the standard resistance bridge region;

[0116] Level 3, l=120μm; third bridge length in the low resistance bridge region, second bridge length in the standard resistance bridge region;

[0117] Level 4, l=150μm; fourth bridge length in the low resistance bridge region, third bridge length in the standard resistance bridge region;

[0118] Level 5, l=180μm; fifth bridge length in the low resistance bridge region, fourth bridge length in the standard resistance bridge region;

[0119] Level 6, l=210μm; fifth bridge length in the standard resistance bridge region.

[0120] Next, combined Figures 4a-4c This invention describes a method for determining the design parameters of a transducer chip for safe ignition, according to one embodiment of the present invention.

[0121] To meet the requirements for pyrotechnic breakdown resistance and insulation: the electrostatic breakdown voltage at the boundary between the bridged diaphragm chip and the substrate should be no less than 25kV, and the insulation resistance should be no less than 10 Ω. 10 Ω; In one embodiment of this application, the transducer chip further includes an H-shaped pad disposed in the bridge region. The transducer chip is disposed on the substrate, and the distance between the outer circle of the H-shaped pad and the boundary of the substrate is... Greater than 1 millimeter.

[0122] Figure 4a A schematic diagram of the transducer structure in one embodiment of the present invention is shown, as follows: Figure 4a As shown, the transducer includes a bridge diaphragm chip, a substrate, electrodes, and solder joints. The bridge diaphragm chip is an electrothermal transducer, the substrate is the transducer molding component, the electrodes are the transducer electrical input components, and the solder joints are the connection components between the bridge diaphragm chip and the electrodes. The bridge diaphragm chip is the core component of the bridge diaphragm transducer, mainly composed of a bridge region, solder pads, and a substrate.

[0123] Figure 4b It shows Figure 4a The diagram shows a bottom view of the transducer. Figure 4c It shows Figure 4a The top view of the transducer shown is as follows: Figure 4b and Figure 4c As shown, The distance between the electrode centers. The diameter of the circumcircle of the pad. The diameter of the electrode. The diameter of the bridge plug substrate is given, and the pad length L covers the center of the electrode. The distance between the circumcircle of the pad and the substrate boundary is also given. The width W and length L should be greater than 1 mm, and the graphic parameters of the pad structure should meet the requirements of chip packaging, chip-substrate anti-breakdown and insulation, etc. The relationship between the width W and length L should meet the following equation (13):

[0124] (13)

[0125] When the substrate is a 95% precision ceramic (Al2O3) electrode plug substrate, the distance between the bridge diaphragm chip pads and the outer circle of the substrate in this embodiment is greater than 1 mm. Therefore, the insulation of the bridge diaphragm chip can meet the requirements of national standard GB / T5593-1999, and its breakdown strength is greater than 25 kV / mm; its resistivity at 300℃ is greater than 10 Ω·cm. 11 Ωcm; the tangent of the dielectric loss angle at 1 MHz RF is greater than 5 × 10⁻⁶. -4 .

[0126] The method for determining the design parameters of the transducer chip for safe ignition of the present invention is used to design the chip, and low-resistance bridge film chip and standard resistance bridge film chip are prepared respectively.

[0127] The specific steps include: designing the bridge diaphragm resistor based on the fusing current; designing the V-angle based on the critical burst current; calculating the aspect ratio based on the resistance and V-angle; designing the bridge length based on the ignition time requirements; and calculating the bridge width based on the bridge length and aspect ratio.

[0128] To facilitate the description of bridge zone specifications, bridge zones are numbered according to a numbering rule. The bridge zone number reflects the material, thickness, resistance, and bridge shape information, and is a field containing five characters, such as... Figure 5 As shown:

[0129] The first letter is a letter indicating the material of the bridge area, which is a capital letter: C for nickel-chromium alloy and N for tantalum nitride.

[0130] The second digit is a number digit, representing the bridge thickness (μm).

[0131] The third position is a letter, indicating the type of resistor (S, M).

[0132] The fourth digit is a number indicating the type of V-angle (0 indicates θ=180°, 1 indicates θ=150°, 2 indicates θ=120°, 3 indicates θ=90°).

[0133] The fifth digit is a number that indicates the bridge length classification.

[0134] For example, the chip number C2S24 indicates a low-resistance bridge region with a thickness of 2μm, fabricated using chip technology, with a V-angle of 120° and a bridge length of 150μm.

[0135] Specifically, a 2μm nickel-chromium alloy film was used to design and calculate the bridge region pattern and quality for low resistance. The results are shown in Table 1. Table 1 shows the parameters of the low-resistance (R=0.67±0.07Ω) bridge region pattern.

[0136] Table 1

[0137]

[0138] A 2μm nickel-chromium alloy film was used to design and calculate the bridge pattern and quality of the standard resistor. The results are shown in Table 2. Table 2 shows the bridge pattern parameters of the standard resistor (R=1.00±0.10Ω).

[0139] Table 2

[0140]

[0141] After completing the design of the bridge region pattern, the bridge diaphragm chip is designed. The bridge diaphragm chip design includes the design of the substrate, bridge region, and pads. The bridge diaphragm chip design is based on the substrate material, size, and insulation requirements, and on the basis of the bridge region design, the substrate thickness, bridge diaphragm pattern, and pad size are designed. Specifically, the substrate thickness is selected, the pad pattern is H-shaped, and the maximum size of the H-shape is calculated according to formula (21).

[0142] To facilitate the description of bridge diaphragm chip specifications, the bridge diaphragm chips are numbered according to the bridge diaphragm chip numbering rules. In addition to reflecting bridge region information, the bridge diaphragm chip number also reflects the substrate material, thickness, and chip pattern information.

[0143] like Figure 6 As shown, W represents the pad width, L represents the pad length, and h represents the substrate thickness.

[0144] like Figure 7 As shown, the bridge diaphragm chip number consists of two fields separated by a " / ". The first field is the bridge area number; the second field contains three characters:

[0145] The first digit indicates the substrate material: T indicates a ceramic substrate, and S indicates a silicon substrate;

[0146] The second digit indicates the substrate thickness grade: Grade 1 is 0.25mm, Grade 2 is 0.50mm, and Grade 3 is 1.0mm;

[0147] The third character indicates the pad size classification: The H pad is classified by length, with the first level being 0.75±0.10mm, the second level being 1.50±0.15mm, the third level being 2.00±0.20mm, and the fourth level being 2.50±0.25mm.

[0148] therefore, Figure 7 The bridge chip number C2M24 / T13 shown means: the bridge chip substrate uses a 0.25mm thick ceramic wafer and a 2.00mm long pad, and the bridge area is packaged with the number C2M24.

[0149] Two types of bridge diaphragm chips with resistances of 0.67±0.07Ω and 1.00±0.10Ω, respectively, were designed and fabricated using this method. The bridge diaphragm chip transducers integrated with the two types of bridge diaphragm chips and φ6.0mm electrode plugs exhibited current stability higher than 2A for 5 minutes without melting and 1.5A for 2.25W for 5 minutes without melting, respectively, with critical burst currents greater than 3.9A and 2.8A, respectively. Verification through electrode plug encapsulation and lead styrene ignition tests showed that they met the requirements of 1.5A for 5 minutes without ignition and 1A for 1W for 5 minutes without ignition, respectively, with critical ignition currents less than 4.3A and 3.5A, respectively.

[0150] Following the fabrication process of bridged membrane chips, a 4-inch ceramic substrate with a thickness of 0.25 mm (Type 1) was selected as the chip substrate, and the H-type chip size was divided into four length levels. Six types of low-resistance bridged membrane chips were fabricated by selecting Type 1 and Type 2 V-angles and three bridge lengths (Types 2, 4, and 6).

[0151] Following the fabrication process of the bridge film chip, a 4-inch ceramic substrate with a thickness of 0.25 mm (Type 1) was selected as the chip substrate, and the H-type chip size was divided into four length levels. Types 2 and 3 V-angles and three bridge lengths (Levels 2, 4, and 6) were selected to fabricate a total of six standard resistor bridge film chips.

[0152] To verify the effectiveness of the method of the present invention, chip testing was conducted below through bridge diaphragm chip electrothermal performance test and bridge diaphragm chip ignition performance test.

[0153] Using 6mm diameter electrode plugs as the substrate, the electrothermal performance of six low-resistivity and six standard resistance chips was tested according to the "Test Method for Non-Fusing Current of Resistive Transducers," "Test Method for Critical Burst Current of Resistive Transducers," and "Test Method for Burst Time of Resistive Transducers." The results are shown in Table 3. Table 3 presents the test results of the electrothermal performance of 12 bridge diaphragm chips.

[0154] Table 3

[0155]

[0156] Table 3 shows that all low-resistance bridge film chips meet the requirement of current stability of not less than 2A for 5 minutes without melting, while all standard resistance bridge film chips meet the requirement of current stability of not less than 1.5A for 5 minutes. Furthermore, the 5-minute non-melting current of the low-resistance bridge film chips is higher than that of the standard resistance bridge film chips. Specifically, comparing the C2S22 and C2M22 bridge film chips, with the same bridge length and V-angle, the 5-minute non-melting current of the low-resistance bridge film chips is 0.6A higher than that of the standard resistance bridge film chips, an improvement of over 25%. With the chip resistance and bridge length remaining the same, changing only the V-angle reveals that a smaller V-angle results in a shorter burst time. Specifically, compared to C2S12 and C2S22, the burst time is reduced by 22%; compared to C2M22 and C2M32, the burst time is reduced by 64%. With the chip resistance and V-angle remaining the same, changing only the bridge length reveals that decreasing the bridge length reduces the critical burst current. Specifically, compared to C2M26 and C2M22, the critical burst current is reduced by 28%.

[0157] Lead stearate (LTNR) was used as the ignition agent. Tests were conducted on six types of low-resistance and six types of standard resistance chips according to the "Test Method for Safe Current of Pyrotechnics," "Test Method for Critical Ignition Current of Pyrotechnics," and "Test Method for Action Time of Pyrotechnics." The results are shown in Table 4. Table 4 presents the test results of the ignition performance of 12 bridge diaphragm chips on LTNR.

[0158] Table 4

[0159]

[0160] Table 4 shows that the safe current for LTNR reagent using the low-resistance bridge film chip is no less than 1.5A, while the safe current for LTNR reagent using the standard resistance bridge film chip is no less than 1.0A. Furthermore, the safe current of the low-resistance bridge film chip is consistently higher than that of the standard resistance bridge film chip. Specifically, comparing the C2S22 and C2M22 bridge film chips, with the same bridge length and V-angle, the safe current of the low-resistance bridge film chip is 0.4A higher than that of the standard resistance bridge film chip, representing an improvement of over 36%. With the chip resistance and bridge length remaining constant, changing only the V-angle reveals that a smaller V-angle results in a shorter 6A ignition time. Specifically, compared to C2S12 and C2S22, the 6A ignition time is reduced by 4%; compared to C2M22 and C2M32, the 6A ignition time is reduced by 9.5%. With the chip resistance and V-angle remaining constant, changing only the bridge length reveals that a smaller bridge length results in a shorter critical ignition current. Specifically, compared to C2M26 and C2M22, the critical ignition current is reduced by 24%.

[0161] The present invention also provides a transducer chip for pyrotechnic devices, wherein the design parameters of the transducer chip are obtained by the transducer chip design parameter determination method for safe ignition described in any of the above embodiments.

[0162] The working principle of the transducer chip is as follows: When a rapidly rising current / voltage pulse is applied to the electrodes at both ends of the bridge region, the current / voltage at the bridge edge with the largest current / voltage gradient generates a glow discharge and excites the center of the bridge. The bridge region material melts and forms a superheated ionized vapor layer in the bridge region, generating a strong plasma glow discharge gas. When the incandescent silicon plasma particles penetrate into the adjacent explosive powder, they condense on the explosive particles and exchange heat, thus igniting the explosive in the pyrotechnic device and causing an explosion.

[0163] The following describes the fabrication method of the bridged membrane chip.

[0164] Figure 8 A flowchart of the bridge diaphragm chip fabrication process, such as Figure 8As shown, the fabrication process of bridged membrane chips can be divided into three parts: preparation, sputtering deposition, and post-processing. The detailed process is described below:

[0165] In the preparation process, the first step is to polish and (ultrasonically) clean a complete ceramic substrate on both sides to improve the surface smoothness, facilitate sputtering, and enhance the adhesion of the metal coating. Substrate grooving refers to dividing the complete ceramic substrate into several bridge film substrates of the required size. The above steps are the preparatory work before sputtering.

[0166] Sputtering a coating onto the substrate is a crucial step in fabricating bridged-film chips. First, a titanium (Ti) substrate and a nickel-chromium alloy (Ni-Cr) resistive film, 2 μm thick, are sputtered onto the front side of the ceramic substrate. After sputtering, the bridged-film pattern is etched using wet etching. A gold (Au) conductive layer is then sputtered onto the etched pads. Subsequently, a mask is used to cover the non-pad areas, and the pad conductive layer is etched again using wet etching. These steps are essential for fabricating bridged-film chips, primarily using magnetron sputtering and wet etching methods. The technical challenge lies in etching the bridged-film pattern after sputtering.

[0167] The post-processing work involves further processing of the bridge diaphragm chip after sputtering deposition. This includes sputtering and wet etching of the back conductive layer (Au) on the bridge diaphragm; sputtering of the side conductive layer (Au), a crucial step in the post-processing, which thickens the soldering area and improves conductivity during soldering; fabrication of a metal protective layer, using vacuum evaporation to deposit a gold (Au) layer of tens of nanometers on the bridge diaphragm chip as a protective layer; and finally, the fabricated chips are individually diced for chip testing.

[0168] The present invention also provides a bridged membrane transducer, comprising the transducer chip and the substrate described above, wherein the transducer chip is fixed on the substrate.

[0169] The following combination Figure 9 This invention will illustrate an integration process method for a bridge diaphragm transducer according to one embodiment. Bridge diaphragm transducer integration refers to the process of integrating a bridge diaphragm transducer chip with a substrate to form a bridge diaphragm transducer, such as... Figure 9 As shown, the fabrication process of the bridge diaphragm transducer includes substrate preparation, chip fixing, solder joint welding, and post-processing. The detailed process flow is as follows:

[0170] The substrate preparation process includes grinding the substrate surface and cleaning it with ultrasonic waves, followed by blowing and drying.

[0171] The chip fixing process involves applying die-attach adhesive to the prepared substrate bottom groove, fixing the chip in the designated position, and then baking it at 150℃ for 2 hours.

[0172] The solder joint welding process refers to applying an appropriate amount of solder paste to the solder joint, i.e., the side of the chip, with the solder paste height not exceeding 3 / 4 of the chip, and then soldering using a reflow soldering process at 250℃ and 500mm / s.

[0173] Post-processing refers to the process of filling the gaps between the bridge diaphragm chip and the substrate on the bridge diaphragm transducer after welding, i.e., applying gap filler.

[0174] Finally, it should be noted that the above technical solution is only one embodiment of the present invention. For those skilled in the art, based on the application methods and principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the methods described in the above specific embodiments of the present invention. Therefore, the methods described above are only preferred and have no limiting significance.

Claims

1. A method for determining the design parameters of a transducer chip for safe ignition, wherein the transducer chip includes a bridge region having a V-shaped structure, characterized in that, The method includes: The bridge resistance value is set according to the preset fuse current of the bridge area; Under a preset burst current input, the angle of the V-shaped angle in the V-shaped structure is set according to the preset burst time of the bridge region; The aspect ratio of the bridge region is determined based on the angle of the V-shaped angle and the resistance value of the bridge region. The bridge length is set according to the preset critical burst current, and the bridge width is determined according to the aspect ratio of the bridge region and the bridge length.

2. The method for determining the design parameters of a transducer chip for safe ignition according to claim 1, characterized in that: Based on the preset fusing current of the bridge section, the bridge resistance value of the bridge section is set according to the following formula: , where R b0 For the bridge region at room temperature, T bd Where T is the critical melting temperature, T0 is the initial temperature, and I is... d χ is the critical fusing current of the bridge region, where χ is the heat dissipation coefficient of the bridge diaphragm chip and specific integrated components to the environment, and S is the thermal conductivity coefficient. c This represents the heat dissipation area.

3. The method for determining the design parameters of a transducer chip for safe ignition according to claim 1, characterized in that: When the transducer chip is a short-pulse constant current input, under a preset burst current input, the angle of the V-shaped angle in the V-shaped structure is set according to the preset burst time of the bridge region based on the following formula: ,in, ρ is the heat capacity of the bridge material, δ is the thickness of the bridge region, and ρ is the thickness of the bridge material. b For the density of the bridge material, The burst temperature, The initial temperature of the bridge area. R is the narrowest width ratio, η is the bridge region self-retaining thermal coefficient under short pulse constant current input, and R is the narrowest width ratio. s For the structural resistance of the bridge area materials, I e The preset burst current is given, ω is the aspect ratio of the bridge region, and t is the value of the burst current. e The preset burst time is given by l, where l is the bridge length.

4. The method for determining the design parameters of a transducer chip for safe ignition according to claim 1, characterized in that: Based on the angle of the V-shaped angle and the resistance value of the bridge region, the aspect ratio of the bridge region is determined using the following formula: ,in, R is the aspect ratio of the bridge area. b0 R is the resistance at room temperature in the bridge region. s Let θ be the sheet resistance of the bridge material, and θ be the angle of the V-shaped angle.

5. The method for determining the design parameters of a transducer chip for safe ignition according to claim 1, characterized in that: The bridge length is determined based on the preset critical burst current and the following formula: , among which, I ec To preset the critical burst current, t ec The burst time used for the preset critical burst current.

6. The method for determining the design parameters of a transducer chip for safe ignition according to any one of claims 1 to 5, characterized in that: The bridge region room temperature resistance R b0 The value range is 0.6Ω ≤ R b0 ≤1.1Ω.

7. The method for determining the design parameters of a transducer chip for safe ignition according to any one of claims 1 to 5, characterized in that: The range of the angle θ of the V-shape is as follows: The bridge length l of the bridge area is in the range of 60μm≤l≤210μm.

8. The method for determining the design parameters of a transducer chip for safe ignition according to any one of claims 1 to 5, characterized in that: The transducer chip also includes H-shaped pads disposed on both sides of the bridge region. The transducer chip is disposed on the substrate, and the distance between the outer circle of the H-shaped pad and the boundary of the substrate is greater than 1 mm.

9. A transducer chip for a pyrotechnic device, characterized in that: The design parameters of the transducer chip are obtained by the method for determining the design parameters of a transducer chip for safe ignition as described in any one of claims 1 to 8.

10. A bridged membrane transducer, characterized in that: It includes the transducer chip and the substrate as described in claim 9, wherein the transducer chip is fixed on the substrate.

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