Base body having a brazed ground ped and method for producing

Abstract

The invention relates to a base body for a feed-through element, comprising a metallic base body (1), at least one through-hole (4) for receiving a functional element in a fastening material (10), in particular an electrically insulating fastening material (10), and at least one conductor (6) which is electrically conductively connected to the base body by means of a brazing connection. The brazed connection comprises a metal solder (7) which covers a surface region of the substrate such that a brazed region (7) is formed on the surface of the substrate. The main body (1) has a microstructure at least in the brazing region (7), said microstructure comprising at least recesses in the surface of the main body. The invention likewise relates to a method for producing such a substrate (1) and to the use thereof.

Description

[0001] The present application is a divisional application of patent application No. 201811137765.4 with the title "Substrate with soldered ground pin and method of manufacturing and use thereof", filed on September 28, 2018. TECHNICAL FIELD

[0002] The present invention generally relates to substrates for feedthrough elements, such as for sensors and / or large feedthroughs and / or transistor outline packages and / or battery or capacitor feedthroughs, and also to such feedthroughs themselves. In particular, feedthroughs for triggering devices are provided, such as for triggering pyrotechnic personal protection devices in airbag igniters and / or seatbelt tensioners and / or gas generators. The invention particularly relates to the design of the header of such feedthrough elements, and to the method of manufacturing and use thereof. BACKGROUND

[0003] In particular, feedthroughs for sensors can power the sensor elements and / or pass their signals to an evaluation unit. Large feedthroughs are typically used in safety housings, such as for liquefied gas tanks and / or reactors.

[0004] Battery or capacitor feedthroughs are generally understood to mean feedthroughs through the housing of a battery, including rechargeable batteries, or a capacitor. The term likewise encompasses the field of supercapacitors, also known as ultracapacitors. The feedthroughs are typically used to contact the electrodes inside the battery or capacitor housing.

[0005] Transistor outline packages, also known as TO packages, are current-carrying housings for electronic devices. A TO package essentially comprises two components, namely a header and a cap. The header primarily ensures the supply of power to the packaged elements, while the cap is used in the field of optoelectronics in order to reliably transmit optical signals. This includes both emitters, such as laser diodes, and optical signal receivers, such as photodiodes. The TO header represents a mechanical base for mounting electronic and optical components, such as semiconductors, laser diodes or simple circuits. At the same time, it supplies the protected components with power via terminal pins.

[0006] In particular, airbags and / or seatbelt tensioners are used as pyrotechnic personal protection devices in motor vehicles. Such safety systems can significantly reduce the risk of injury. However, a prerequisite is that the safety systems involved do not fail in the event of a crash. In this case, particular attention is also paid to the igniters of such pyrotechnic devices, which are essential for the functioning of such safety devices. In particular, the igniters must still function properly many years after their manufacture. The average service life of such igniters is usually specified as fifteen years. In order to ensure proper long-term functioning, it must be ensured that the propellant provided in the igniter does not change over time. Such changes can be caused, for example, by moisture entering the igniter. It is therefore of great importance to seal the propellant of the igniter. The igniter must also release the gas of the ignited propellant in the correct direction in order to ignite the propellant of the gas generator of the safety system.

[0007] In order to ensure this, the igniters known from the prior art have a cover or cap and a relatively large header between which the propellant is enclosed in a cavity formed by these components. The electric current for igniting the propellant is transmitted through the header using electrical terminals. The header therefore usually has a through-hole in which a metal pin is present, which can be supplied with electricity on one side via a plug connection and is connected on the other side, for example, via a firing bridge, which results in the propellant igniting when the current flows through it and comes into contact with the latter. The header is therefore also referred to as a feedthrough element. In designing the feedthrough element, it must be ensured that the cover or cap or a part thereof is always detached when the propellant is ignited and that the electrical feedthrough is not expelled from the header.

[0008] In the case of such a feedthrough element, the base body of the header consists of metal and the firing bridge is realized by means of a welded bridge. In the case of this embodiment, the metal pin is fixed as a pin in an electrically insulating fixing material in the through-hole of the base body. Usually used as fixing material is a glass material, in particular a hard glass or a glass solder. The metal pin is therefore insulated with respect to the outer conductor by means of the glass.

[0009] Likewise, ceramics, glass-ceramics and / or polymers can be used as insulating material.

[0010] The second metal pin is welded or soldered as a pin to the outer conductor, which is represented by the base body, also referred to as substrate. On the upper side of the feedthrough element, i.e. on the side facing the ignition cap of the ignition device finally installed, this bridge, usually a tungsten alloy, comes into contact with the surface of the glass material. In order to make the bridge not be damaged and to give the ignition element a long service life during use, for example in a motor vehicle, the surface of the glass material must usually be polished, since a rough surface would damage the bridge.

[0011] The length of the bridging line influences the electrical resistance and thus the triggering behavior of the ignition device. In the case of ignition, the resulting explosion pressure presses on a small surface area of the glass, so that this embodiment is considered to be very robust. A further advantage of this embodiment is that the pin is directly connected to the outer conductor and that simple grounding of the igniter is achieved via this pin. This pin is generally referred to as a ground conductor or ground pin.

[0012] A reliable connection of the ground conductor to the header and / or to the base body is of great importance for the long-term operational reliability of, in particular, airbag igniters and / or seatbelt tensioners and / or gas generators. Defective connections must be avoided, which can occur when the ground conductor is torn off the header during operation and / or when there are large temperature and / or vibration fluctuations. Similarly, the assembly of the airbag igniter and / or seatbelt tensioner can damage or weaken the connection between the ground conductor and the header and / or base body if, for example, the conductor is pushed into the connector and thus subjected to mechanical loads.

[0013] Ignition devices of the type described above are known, for example, from DE 101 33 223 A1, in which the ground pin is welded flush to the base body. In this case, the flush welding means that the end face of the ground pin is welded to the area of the surface of the base body.

[0014] A TO package, for example, is shown in US 8,908,728 B1. Here, it is conceivable to connect a ground pin to the base body in order to electrically ground the base body.

[0015] Large feedthroughs are described, for example, in DE 10 2007 061 175 B3. The base body is usually manufactured by a machining method, for example by turning a preform on a lathe. Here, too, it is possible to connect a ground pin to the base body.

[0016] Generally, the ground pin can be connected to the base body by a soldering method (instead of a welding method), in particular a flush soldering. Generally, a metal solder is used which melts under the effect of heat. In this case, a solder meniscus and / or a solder gap is formed by the metal solder which covers the area of the ground pin at its soldering end and at an area of the base body and thus connects the ground pin to the base body in an electrically conductive and mechanically fixed manner. The dimensions of the area on the base body which is covered by the solder meniscus and / or the dimensions of the solder gap, including the thickness of the solder gap, are difficult to control. This leads to problems with the further processing of the base body, i.e. the metal solder can reach the side of the base body through the edges of the latter and the further processing there will be more difficult. For example, when the base body is used for an airbag igniter, a cover is pushed onto the side of the base body and welded there by laser welding. The solder which is placed on the side then creates an obstacle and / or at least makes the situation worse. The situation is equally serious if the metal solder gets into the through-hole. If the solder penetrates between the insulating material and the base body in the through-hole, i.e. generally between the enameled glass and the outer conductor, there is a greater risk that the mechanical strength of the connection between the insulating material and the base body within the through-hole is reduced to a critical extent. This mechanical strength can be tested by a glass extrusion test. This is a regular measure in the industrial mass production of these components.

[0017] Similarly, a poorly formed solder meniscus and / or solder gap or a poorly formed soldering location can lead to a mechanical instability of the soldered ground pin. The mechanical stability of the latter, i.e. of the soldering connection between the ground pin and the base body, is tested by a bending test. In the case of a poor quality of the soldering connection, the ground pin can come off the base body in the bending test. Thus, an uncontrolled structure of the solder meniscus and / or the solder gap leads to random failures in the bending test. SUMMARY

[0018] Against this background, it is an object of the present application to provide a base body for a feedthrough element in order to reduce the disadvantages of the prior art and to provide a reliable soldering connection between the electrical conductor and the base body. The base body can be efficiently manufactured in industrial mass production and has a low reject rate.

[0019] This object is achieved by the base body according to the independent claims and the manufacturing method thereof. Preferred embodiments and applications are provided by the claims dependent thereon. The same applies to the feedthrough element according to the application which is produced from the base body and to its applications.

[0020] The base body according to the application comprises a metal base body and at least one through-hole for accommodating a functional element, in particular an electrically insulating fixing material. The functional element can be an electrical conductor or comprise an electrical conductor, but also an optical element and / or a thermocouple and / or a waveguide, etc. The feed-through element according to the application further comprises at least one conductor which is in electrically conductive connection with the base body by means of a solder connection. The solder connection comprises a metal solder which covers a surface area of the base body and thus forms a solder area on the surface of the base body.

[0021] The solder area is thus defined as the area on the surface of the base body which is covered by the metal solder. According to the application, the base body has a microstructure at least in the solder area, which microstructure comprises at least recesses in the surface of the base body. This especially refers to recesses in which the deepest point below the surface of the base body lies outside the solder area. In general, the recesses can be separated from one another by webs. The webs can extend back, measured below the surface of the base body, outside the solder area, i.e. outside the solder area below the plane of the surface of the base body. As mentioned above, this means that the metal solder covers the microstructure in the solder area. The metal solder and the microstructure together act, which embodies the advantages of the application.

[0022] The microstructure according to the application is characterized in that it is a structure which is deliberately introduced. In particular, the structure consists of a combination of individual structures which are introduced into the base body according to the organizational criteria and thus jointly form the microstructure. This microstructure according to the application is clearly distinguished from scratches and / or indentations which are located in the base body and which can of course be arranged arbitrarily.

[0023] The base body advantageously has at least one flat surface in which the solder area is located. It is particularly advantageous if the base body has two flat, parallel surfaces. The through-hole connects these surfaces. In particular, the base body for an airbag igniter or a seat belt tensioner is disc-shaped. The base body for a battery and / or capacitor housing can advantageously have a rectangular shape.

[0024] The inventors have recognized that the microstructure in the soldering region acts as a solder stop for the metallic solder. As mentioned above, the metallic solder melts and wets the substrate in the soldering region as well as the region of the conductor which is connected to the substrate during the soldering process. During the wetting, the solder flows. Without the microstructure, the flow of the solder would be difficult to control. The inventors have recognized that the microstructure limits the flow of the melted solder. In this way, the flow of the metallic solder can be controlled by introducing the microstructure. Accordingly, the microstructure is a solder stop for the metallic solder. As a result, in the production of a plurality of substrates according to the present invention, the variation of the diameter of the soldering region is smaller than without the microstructure. With the presence of the microstructure in the soldering region according to the present invention, the diameter of the soldering region can be reliably controlled. It can be stated at the same time that the limitation of the solder flow does not have to be at the periphery of the microstructure, but rather such a limitation is already on the individual elements of the microstructure, that is to say, as in the region of the microstructure.

[0025] Preferably, the recesses of the microstructure form a substantially regular pattern. Particularly preferably, the recesses of the microstructure are arranged next to one another and / or they overlap at least in certain regions. Particularly preferably, the microstructure is formed as a grid of dots and / or as a structure of a mesh and / or as a structure of scales in a plan view.

[0026] Most particularly preferably, the recesses of the microstructure are laser structure regions in the surface of the substrate. Advantageously, these laser structure regions can be laser ablation regions and / or regions which are locally reformed by laser radiation and / or regions which are locally reformed by a laser-induced pressure effect. It goes without saying that any combination is possible. Further details in this respect will be explained in the following paragraphs.

[0027] Alternatively, the present invention can be implemented and similarly encompasses other possibilities for producing the microstructure, for example, by stamping with a microstructured stamp and / or by material-removing methods, for example, milling and / or scoring, etc.

[0028] Advantageously, the microstructure is in the form of grooves and / or the microstructure comprises or consists of recesses having a circular and / or elliptical diameter. Rectangular diameters, in particular with rounded corners, are also equally possible. It is particularly advantageous for the recesses to be in the form of craters and / or cups. These forms can be produced particularly advantageously by laser ablation, and / or laser desorption or other laser-assisted methods.

[0029] Preferably, the recesses of the microstructure have a depth of up to 70 pm, advantageously of 0.7 pm to 70 pm, more advantageously of 0.7 pm to 50 pm, more advantageously of 0.7 pm to 20 pm, particularly advantageously of 1 pm to 10 pm, most particularly preferably of 2 pm to 10 pm. The depth is measured from the plane of the surface of the base outside the microstructure to the deepest point of the microstructure, i.e. in the case of recesses in the form of pits, from the plane of the surface of the base outside the microstructure to the lowest point of the pit bottom. It goes without saying that the present application likewise provides and encompasses microstructures which are located over the entire surface of the base. The depth of the recesses of the microstructure is then measured from the plane of the average of the highest points of the webs located between the recesses and / or delimiting them.

[0030] Particularly preferably, the base according to the application has an average roughness Ra≥ 0.35 pm and / or an average surface roughness Rz≥ 1 pm in the region of the microstructure. Most particularly preferably, Ra is in the range from 0.35 pm to 15 pm and / or Rz is in the range from 1 pm to 50 pm, in particular Rz is in the range from 1 pm to 15 pm.

[0031] The average roughness Ra and the average surface roughness Rz are defined in a manner known to the person skilled in the art. The average roughness Ra specifies the average distance of the measuring points within the vertical section, i.e. the profile of the microstructure, from the centre line. The centre line intersects the actual profile within a reference distance such that the sum of the deviations from the centre line is minimised. The average roughness Ra thus corresponds to the arithmetic mean of the absolute values of the deviations from the centre line. Rz is the so-called average surface roughness. It represents the arithmetic mean of the individual roughnesses within five measuring distances. Rz is determined by dividing the defined measuring distance on the surface of the base within the microstructure by seven individual measuring distances, wherein the middle five measuring distances have the same size. The evaluation is made on the basis of only these five measuring distances. From each of these individual measuring distances according to the profile of the microstructure, the difference to the maximum and minimum value is determined. From the five individual surface roughnesses thus obtained, the average value Rz is formed.

[0032] Advantageously, the recesses of the microstructure are formed such that between the individual recesses there are webs which separate the individual recesses from one another and / or delimit them. The web width is variable and can be from less than 1 pm, for example, to about 100 pm, or 50 pm, or 20 pm or 10 pm.

[0033] Particularly preferably, the diameter of the recesses of the microstructure is 10 pm to 150 pm, in particular 10 pm to 120 pm, in particular 50 pm to 150 pm, in particular 50 pm to 120 pm, measured at the narrowest point. Likewise, the appropriate lower limit of all these ranges mentioned is 80 pm.

[0034] Most particularly preferably, the microstructure of the base body is adjusted at least in the soldering region by introducing the microstructure. In particular, prior to the soldering process, interfering substances are substantially removed, for example at least in the recesses of the microstructure, which can reach the base body during the manufacturing process, in particular an unwanted oxide layer and / or deposits (in particular lubricants). Accordingly, at least in the recesses, the surface of the microstructure is most particularly preferably free of organic materials and / or free of carbon. In particular, a pure metal surface or a substantially homogeneous and preferably thin oxide layer is present in the recesses, which preferably has a thickness of less than 10 nm, in particular preferably 1 nm to 6 nm.

[0035] Prior to the introduction of the microstructure, the metal base body usually has a natural oxide layer. This is usually inhomogeneous in its composition and / or in particular in its thickness. Furthermore, the metal base body is usually brought into the desired form by metalworking methods, for example by turning on a lathe and / or by stamping and / or cold forming and / or cutting. Similarly, through-holes are introduced, for example by drilling and / or punching.

[0036] Similarly, residues of lubricants (for example lubricants of the manufacturing machines) can be present on the base body. Such lubricants and their residues can in particular be oils which contain organic substances and / or are usually carbon compounds. By introducing the microstructure, these interfering oxide layers and / or residues are at least partially removed at least in the soldering region. When the natural oxide layer is removed, a bare metal surface (in particular preferably at least in the recesses of the microstructure) remains, but it can also be reoxidized. In comparison to the natural oxide layer, this reoxidized surface has a smaller layer thickness and greater homogeneity. It does not (or at least to a very small extent) interfere with the soldering process and the formation of the soldered connection.

[0037] In a particularly preferred embodiment, the webs between the recesses of the microstructure are covered by a different oxide layer (than the surface within the recesses). Thus, the oxide layer on the webs is different from the oxide layer located on the surface of the recesses. Similarly, by said means it is possible for the webs to be covered by an oxide layer and the surface of the recesses to be substantially a bare metal surface.

[0038] Common steels such as St 35 and / or St 37 and / or St 38, or high-grade steels and / or stainless steels are generally used as base material. High-grade steels in accordance with DIN EN 10020 are the term for alloyed or non-alloyed steels with a sulphur and phosphorus content (so-called accompanying elements) of not more than 0.035%. In the following, a further heat treatment (for example hardening and tempering) is generally provided. High-grade steels include, for example, high-purity steels in which components such as aluminium and silicon are separated off from the melt by special manufacturing methods, and also alloyed tool steels for subsequent heat treatment. These steels contain, in particular, chromium. For example, the following can be used: X12CrMoS17, X5CrNi1810, XCrNiS189, X2CrNi1911, X12CrNi177, X5CrNiMo17-12-2, X6CrNiMoTi17-12-2, X6CrNiTi1810 and X15CrNiSi25-20, X10CrNi1808, X2CrNiMo17-12-2, X6CrNiMoTi17-12-2.

[0039] However, in order to ensure maximum cost efficiency of the feedthrough element according to the application, the metal base can also advantageously not consist of a high-grade steel. Advantageously, the base is made of a steel from the group 1.01xx to 1.07xx (non-alloyed high-quality steel). In this case, the steel group is specified in accordance with DIN EN 10 027-2, wherein the first number gives the main material group and the number sequence after the first point gives the steel group number.

[0040] In order to ensure optimum corrosion resistance, the base can be coated with a metal. Preferably, a nickel coating is used. This is particularly suitable for bases made of non-alloyed high-quality steel.

[0041] Preferably, the base according to the application comprises a chromium-containing metal, in particular a chromium-containing high-grade steel, at least in the region of the microstructure. Similarly, preferably, the base consists of a chromium-containing metal, in particular a chromium-containing high-grade steel. Then, in the recesses of the microstructure, the surface is covered in particular by a homogeneous layer comprising CrO X . Particularly preferably, this homogeneous layer comprises CrO X (OH) 2-X • nH2O or consists of CrO X (OH) 2-X • nH2O. These said layers can in particular be produced by natural oxidation which occurs when the said materials are used.

[0042] Preferably, a hard solder is used as the metallic solder. Commonly referred to as hard solder are alloys based on high silver content, on nickel-silver and / or on brass, which are usually in the form of rods, bars, wires, thin films, sometimes in the form of pastes. Hard solder pastes already contain fluxes, so that in the case of solder pastes as well (as in other forms of solder) no separate addition of these fluxes is necessary. Usually, hard solders containing palladium (Pd) are used for airbag igniters and / or seat belt tensioners. Hard solders containing Pd have a particularly good soldering bondability on metal substrates, among other things.

[0043] Particularly preferred for the purposes of the present application is a metallic solder which is essentially free of palladium (Pd). By "essentially free" is meant in addition to impurities and / or natural isotopic ratios. The order of magnitude of these impurities can be up to 2000 ppm, in particular up to 1000 ppm. The present application can use a metallic solder which is essentially free of Pd, in particular in the case of a microstructure in the soldering region and a metal conditioning as described in the region of the microstructure, for example in the presence of a thin, homogeneous oxide layer. Since palladium is a very expensive raw material and is considered to be irritating and highly flammable, this particularly preferred embodiment contributes to a particularly advantageous reduction in manufacturing costs.

[0044] By the described electrically conductive connection of the metal pin to the substrate, a solder meniscus is advantageously formed at the transition to the surface of the substrate during melting of the metallic solder. This meniscus has a radius of at most 0.40 mm, particularly advantageously. In the case of a microstructure in the soldering region, this relatively small radius of the meniscus is made possible by the control of the flow of the metallic solder according to the present application.

[0045] Between the end of the metal pin soldered to the substrate and the surface of the substrate, there is a gap filled with metallic solder in the soldering region, referred to as the solder gap. The width of the solder gap, i.e. the thickness of the soldering material between the end of the metal pin and the surface of the substrate, is similarly a measure of the reliability of the soldered connection formed. Therefore, in a particularly preferred embodiment, there is a solder gap filled with metallic solder between the conductor's surface facing the substrate and the microstructured surface of the substrate, the solder gap width of the metallic solder being at most 100 pm, preferably 3 nm to 100 pm, particularly preferably at most 80 pm or at most 70 pm, particularly preferably 3 nm to 70 pm, measured from the lowest point of the recess of the microstructure.

[0046] The quality of the good soldered connection between the ground pin and the base body can be assessed on the basis of the shear force, which is the force required to shear the ground pin, which is connected to the base body, from the metal solder in the soldering area. A particularly advantageous effect brought about by the invention is that the shear force in the case of a base body according to the invention with the microstructure in the soldering area is increased by at least 10% on average compared to the shear force in the case of a conventional base body without microstructure. The shear force is measured by means of a component which is limited in a clamping device and a metal spatula which is passed along the base body. When it encounters the soldered conductor, the force (N) required to shear it is recorded.

[0047] The control of the solder flow by means of the microstructure in the soldering area likewise has the effect that the diameter of the soldering area is smaller compared to a base body without microstructure and with the same amount of metal solder. It has been observed that, in the case of a base body according to the invention, in which the microstructure in particular acts as a solder stop, more solder can be adsorbed on the metal pin compared to the case without microstructure.

[0048] In a particularly advantageous embodiment, the soldering area has a maximum diameter, measured parallel to the surface of the base body, which is at most twice the diameter of the metal pin which is electrically conductive with the base body, i.e. the ground pin. For example, the ground pin can have a diameter of 2 mm. The soldering area can then particularly advantageously have a diameter of at most 4 mm, measured parallel to the surface of the base body. If the diameter of the ground pin is 1 mm, the diameter of the soldering area is at most 2 mm.

[0049] The invention can position the ground pin closer to the periphery of the through-hole and / or at the periphery of the base body, because the flow of solder is controlled by means of the microstructure; and because the risk of hindering further processing is reduced in the case of a flow of metal solder into the through-hole or over the edge of the base body in industrial mass production, i.e. on the inner wall of the through-hole or on the surface of the insulating material arranged therein and / or on the outer peripheral surface of the base body and / or even defective components are produced. If the electrically conductive metal solder flows onto the insulating material in the through-hole in which the functional element is arranged, a short circuit between the functional element and the base body can occur, or at least the flashover voltage is reduced.

[0050] It is particularly preferred that the base body according to the invention is a base body for manufacturing an airbag igniter or a seat belt tensioner or a gas generator, wherein, in the at least one through-hole, a conductor is arranged as a functional element in an electrically insulating fixing material; and the conductor which is in electrically conductive connection with the base body is formed as a ground pin which is soldered flush to the base body in the soldering area. Such a base body is also generally referred to as a manifold.

[0051] Most particularly preferably, the ground pin has a diameter of 1 mm ± 0.02 mm in this application and the radius of the meniscus of the metal solder at the transition to the surface of the base body is less than 0.40 mm, preferably less than 0.36 mm, particularly preferably less than 0.30 mm, most particularly preferably less than 0.22 mm.

[0052] The present application can reduce the amount of metal solder used. In the most particularly preferred embodiment of such a manifold, the volume of metal solder is less than 0.16 mm 3 , preferably less than 0.13 mm 3 , particularly preferably less than 0.10 mm 3 , most particularly preferably less than 0.07 mm 3 .

[0053] In such an application in an airbag igniter and / or a seat belt tensioner and / or a gas generator, the soldering region advantageously has a diameter of 1 mm to 2 mm, measured parallel to the surface of the base body. This means that the diameter of the soldering region can also correspond to the diameter of the ground pin. Then, only the solder gap between the butt end of the ground pin and the base body is provided with metal solder.

[0054] In industrial mass production, the defect rate and / or the ratio of good parts to scrap parts is particularly important. The present application reduces the defect rate and / or increases the ratio of good parts to scrap parts. These are statistical considerations. The results of the bending test carried out on the ground pin provide a measure for assessing these components. This involves investigating the base body by mechanically bending the ground pin at a pivot point near the soldering end of the ground pin. If the soldered connection of the ground pin breaks and the latter thus comes off the base body, the relevant base body is considered not to have passed the test, otherwise it is considered to have passed. The defect rate is the ratio of the number of base bodies investigated by the bending test to the number of base bodies that did not pass the bending test. In the case of base bodies according to the present application, the defect rate in the bending test of a quantity of 5000 base bodies is advantageously less than 1 to 1000 (corresponding to 1 per thousand), particularly advantageously less than 1 to 2000 (corresponding to 0.5 per thousand), particularly advantageously at most 1 to 5000, most particularly advantageously 0 to 5000.

[0055] Another measure for assessing the components is provided by the variation of the diameter of the soldering area in some of the manufactured components. As in the case of each of the manufactured components, the present application attempts to make the diameter of the soldering area as identical as possible, i.e. the aim is to reduce the differences as much as possible. Thus, in the most particularly preferred embodiment, the present application relates to a plurality of substrates for manufacturing inflator igniters, and / or seat belt tensioners and / or gas generators, which comprises 1000 test quantities of substrates according to the present application, wherein the statistical standard deviation of the mean value of the diameter of the soldering area in the test quantities is in the range of 0% to 6% of the mean diameter of the soldering area of the test quantities, measured from the surface parallel to the substrate.

[0056] The present application similarly relates to a method for manufacturing a substrate for a feedthrough element. The method comprises the following method steps, which do not necessarily have to be carried out in the order described herein. From the description, the person skilled in the art is able to add further method steps and / or to change their order to suit his purpose.

[0057] The method according to the present application makes it possible to provide a metal substrate having a predetermined thickness and a predetermined outer contour, which outer contour has two substantially opposite surfaces. At least one through-hole is generated in the substrate. The through-hole communicates the two substantially opposite surfaces. In the method, at least one region of the surface of the substrate is microstructured, wherein recesses are introduced in the surface of the substrate. At least one functional element and an electrically insulating fixing material are also provided. At least one conductor is also provided. The electrically insulating fixing material is arranged in the at least one through-hole, and the at least one functional element is fixed (or in other words, arranged) in the electrically insulating fixing material. It is fixed in the through-hole by the fixing material. The conductor is soldered to the substrate with a metal solder in the region in which the microstructure is present. The metal solder is melted in the soldering process, and the flow of the melted solder is at least prevented and / or limited by the elements of the microstructure. The region of the surface of the substrate which is covered by the solder forms a soldering area, so that the at least one conductor is in electrically conductive connection with the substrate in the soldering area. The conductor represents a ground conductor.

[0058] In particular, the substrate can be a turned part comprising a metal sheet and / or punched out of a metal sheet and / or made from a rod or wire by cold forming. The through-hole can be drilled and / or punched and / or formed in situ, for example during cold forming. According to the manufacturing method, a release agent and / or a lubricant and / or a flow agent, for example an oil, in particular a mineral oil, can be present on the substrate. The surface of the substrate can also be covered by an oxide layer.

[0059] The electrically insulating fixing material is typically a glass material or a glass-ceramic material or a ceramic material or a plastic, for example a high-performance polymer. Combinations of these materials, in particular layered combinations, are also possible. The fixing material can also have a binder and / or a filler. In particular, the functional element can be an electrical conductor, in particular a metal pin, but also a hollow conductor, a thermocouple, a waveguide, a light guide, etc. Typically, the fixing material fuses to the functional element and to the inner wall of the through-hole. In the case of an airbag igniter or a seat belt tensioner, typically used as fixing material is glass, which is ground to a powder and processed with a binder to form a briquette, which is inserted into the through-hole together with the functional element. When it is heated, the binder is typically burned off, the glass melts and adheres to the inner wall of the through-hole and to the functional element. When it cools, the fixing material solidifies and seals the through-hole. The same applies to glass-ceramics, and possibly also to ceramic materials. It is likewise possible to manufacture a preform from parts of the tube.

[0060] When soldering the ground conductor, also referred to as ground pin, likewise a preform of a metal solder is typically used, which likewise can comprise a binder and / or a flux. The preform can be positioned in the area of the subsequent soldering region in the same way as the ground pin and soldered to the base body by heating. The soldering of the ground pin and the fusion of the electrically insulating fixing material to the base body and / or the functional element can also be carried out simultaneously.

[0061] The microstructure can be generated by removing material from the surface of the base body, advantageously by grinding the base body, in particular advantageously by pressing into the base body. The pressing can be carried out, for example, by means of a structured stamp.

[0062] Most particularly advantageously, the microstructure is generated by a laser-induced structuring method and / or a laser structuring method.

[0063] Known laser-induced structuring methods are laser ablation and laser desorption, in which surface material of the base body is removed. However, it is also possible that during irradiation with the laser, the surface material of the base body is reshaped by means of laser irradiation, in particular by locally melting, in particular locally heating the material of the base body and / or by means of a laser-induced pressure effect, in which at least in the vicinity of the base body, the laser radiation locally heats the gaseous atmosphere, in particular locally ignites a plasma, thereby forming a pressure wave which deforms the surface of the base body. In this case, the focus of the laser is in particular located in a plane in front of the surface of the base body. It is also possible to allow the converging laser beam to be reflected by the surface of the base body and to position the focus of the reflected beam in a plane above the base body. Of course, a combination of the two ways of conducting the beam can also be used.

[0064] The laser-based methods described can likewise be combined. For example, the initial material, in particular oxide layers and / or lubricant residues, can be removed from the substrate by laser ablation or laser desorption, wherein the substrate can be locally heated and thus already thermally reformed or at least softened; and / or after exposure of the bare metal surface, the focus of the laser beam can be displaced, in particular a plasma can be ignited in the vicinity of the surface. In this way, pressure waves move in the direction of the substrate and are locally reformed when pressed into the substrate. This reforming can be assisted by thermal softening of the materials described above.

[0065] It is particularly advantageous if all the methods described above are carried out in such a way that the microstructure forms a grid in the form of dots and / or a structure in the form of a mesh and / or a structure in the form of scales in the plan view.

[0066] It is particularly advantageous if, when generating the microstructure, impurities and / or organic substances and / or carbon-containing substances and / or oxides on the surface of the substrate are simultaneously removed. When laser ablation or laser desorption is used, these substances evaporate and / or sublimate.

[0067] After removal of the oxide layer present, re-oxidation can be advantageous. In this regard, an advantageous method provides that, after the microstructure has been formed and before the conductor is soldered, the substrate is covered at least in the region of the microstructure with a substantially homogeneous and thin oxide layer. It is particularly advantageous if, in this case, the oxygen for forming the oxide layer is derived from the ambient atmosphere.

[0068] Corresponding to a particularly preferred method, after the microstructure has been introduced, the substrate is free of organic material and / or free of carbon at least in the recesses. At least in the recesses, it preferably has a pure metal surface or a substantially homogeneous and preferably thin oxide layer, the thickness of which is preferably less than 10 nm, particularly preferably 1 nm to 6 nm.

[0069] The substrate can consist of or comprise the metals described above. In particular, high-grade steels can be used as the material of the substrate. It is likewise possible and more advantageous in terms of method efficiency for the substrate to be made of a steel from group 1.01xx to 1.07xx (according to DIN EN 10 027-2). In particular, the substrate of these materials, in particular together with the through-holes, can be coated with nickel, it being advantageous if the thickness of the nickel layer can be 1 pm to 15 pm, in particular 4 pm to 10 m.

[0070] Particularly advantageously, the matrix is ​​composed of or includes chromium- and / or nickel-containing metals, particularly chromium- and / or nickel-containing steel, including high-grade chromium- and / or nickel-containing steels. Therefore, a preferred structure of the method proposes that: at least in the regions where microstructures exist, the matrix comprises or is composed of chromium-containing metals, particularly chromium- and / or nickel-containing steel, including high-grade chromium- and / or nickel-containing steels; and at least in the recesses of the microstructures, the surface is oxidized by a process including CrO X and / or NiO X A homogeneous layer is used for covering. Preferably, the homogeneous layer comprises CrO. X (OH) 2-X • nH2O or CrO X (OH) 2-X • Composed of nH2O and / or the layer is composed of NiO X (OH) 2-X • nH2O is composed of or includes NiO X (OH) 2-X • nH2O.

[0071] In addition to conventional hard brazing filler metals, the present invention can also use metal brazing filler metals that are substantially free of palladium (generally free of palladium except for impurities) in the method according to the invention.

[0072] To fabricate a brazed connection between the conductor and the substrate, a solder is advantageously placed in a ring around the conductor prior to brazing. During brazing, the solder flows into the microstructure, thus forming a brazing region; in the solder-filled region of the microstructure (8), a solder gap exists between the surfaces of the conductor (6) and the substrate. With the aid of the microstructure, the solder flows beneath the end face of the conductor (particularly in the form of pins), forming and / or filling the solder gap there. The solder material covers and interacts with the microstructure in the brazing region. This has advantages in terms of substrate manufacturability; in particular, it reduces the work required for assembly prior to brazing.

[0073] In a preferred embodiment, the method is performed in such a way that the depth of the microstructure, measured from the substrate surface, is substantially up to 70 μm, particularly up to 50 μm, particularly from 0.7 μm to 70 μm, particularly from 0.7 μm to 50 μm, preferably from 0.7 μm to 20 μm, particularly advantageously from 1 μm to 10 μm, and most particularly advantageously from 2 μm to 10 μm.

[0074] It is particularly preferred that the microstructure is introduced into the substrate in such a way that an average roughness Ra≥ 0.35 μιη and / or an average surface roughness Rz≥ 1 μιη is obtained. Preferably, Ra is in the range of 0.35 μιη to 15 μιη and / or Rz is in the range of 1 μιη to 50 μιη; in particular, Rz is in the range of 1 μιη to 15 μιη. The average roughness Ra and the average surface roughness Rz are defined as above.

[0075] In the method according to the application, the inventors have recognized that during melting of the metal solder, the flow of the solder is limited and / or prevented by the microstructure.

[0076] According to a particularly preferred method, it is conceivable to use a laser structuring and / or a laser-induced structuring method to generate the microstructure. These methods and aspects thereof have already been described above. Advantageously, laser ablation and / or laser desorption are used, in which surface material of the substrate, in particular an oxide layer and / or organic impurities, is removed under the action of laser radiation, exposing a substantially bare metal surface of the substrate that reflects the incident laser radiation. As described above, laser-induced thermal and / or mechanical reshaping and any combination thereof are feasible and encompassed by the present application.

[0077] It is particularly preferred that the bare metal surface exposed, in particular by laser ablation or laser desorption, limits the depth of the microstructure. The inventors have recognized that when laser ablation is used, the depth of the microstructure, and thus Ra or Rz, is automatically set. The impurities located on the substrate, for example residues of lubricants and / or oxide layers, absorb the laser beam, are thus evaporated and / or sublimated, and are thus removed. In particular, the impurities located on the substrate can only partially absorb the laser beam, while the main oxide layer absorbs to a greater extent, up to complete absorption of the laser beam. Only this material is removed, the laser beam can impinge on the subsequently exposed bare metal surface. This reflects the laser beam, which is generally not further removed. This effect is largely independent of the laser power, whereby good reproducibility of the microstructure produced by laser ablation and / or laser desorption can be achieved.

[0078] Since the laser beam is locally limited and, as described above, is performed such that the microstructure preferably occurs in the form of a grid or scale, it initially consists of recesses with a bare metal surface, and webs, for example, with a possibly reduced original oxide layer and / or impurity layer thickness. The recesses with a bare metal surface can be reoxidized under normal environmental conditions. However, this reoxidation apparently occurs homogeneously, forming the above-described oxide layer thickness. A controlled oxide layer is thus formed.

[0079] Laser radiation in the infrared spectral range has proven to be particularly suitable. For example, Nd:YAG lasers can be used. Their emission wavelength is 1064 nm. Further transitions exist at 946 nm, 1320 nm and 1444 nm. The present application can also and encompasses all transitions, including in any desired combination. Likewise, CO2 lasers can be used. These typically emit in the frequency band of 9400 nm and 10 600 nm. Likewise, the substrate surface can be pre-treated with UV laser radiation. This is particularly advantageous for breaking up and / or removing organic and / or carbon-containing impurities. A XeCl-eximer laser with an emission wavelength of 308 nm, and / or a NO2-eximer laser with an emission wavelength of 337 nm, and / or a KrF-eximer laser with an emission wavelength of 248 nm can be used for this purpose, for example. It goes without saying that other suitable UV lasers can likewise be used. In particular, various metals and / or metal oxides can be detached from the metal surface of the substrate by means of a short-pulse UV laser. It has proven suitable in the case of a KrF-eximer laser to use a pulse width of from about 20 ns to about 0.2 ps in order to release, for example, nickel, copper, molybdenum and / or tungsten from the surface of the substrate. Thus, the surface of the substrate can be conditioned by means of suitable laser irradiation, in particular by locally changing the composition of the metal composition of the substrate in the surface region thereof.

[0080] It will be apparent to the person skilled in the art that the entire process of generating the microstructure can likewise be carried out by means of a UV laser. Different lasers can likewise be combined with one another, in particular IR lasers and / or UV lasers and / or lasers having a laser emission wavelength in the visible spectral range. It goes without saying that this likewise includes the interaction of lasers of the same type.

[0081] The substrate according to the application can preferably be used in electrical and / or optical feedthrough elements. It is particularly advantageous if, in at least one through-hole, at least one electrical conductor is arranged electrically insulated from the substrate in the fixing material. It is particularly preferred if the fixing material is a glass, a glass-ceramic material and / or a ceramic material.

[0082] The most particularly preferred use of the substrate according to the application is in pyrotechnic triggering devices and / or airbag igniters and / or seatbelt tensioners and / or gas generators and / or sensors and / or actuators and / or large feedthroughs and / or transistor outline packages.

[0083] The application is explained further on the basis of the following exemplary embodiments and the figures.

[0084] Exemplary embodiments relate to the use of the substrate according to the application in an airbag igniter and / or a seat belt tensioner and / or a gas generator. Since for airbag igniters and / or seat belt tensioners and / or gas generators high explosion pressures of typically more than 1000 bar can occur in the event of ignition, the substrate is typically designed with a correspondingly large thickness, i.e. material strength. The thickness of the substrate is in particular in the range of 1.2 mm to 4 mm, advantageously in the range of 1.5 and 1.7 to 3 mm, particularly advantageously in the range of 1.8 to 2.5 mm. The diameter of the hole of the second through-hole is typically 0.8 mm to 1.5 mm.

[0085] In the case of large feedthroughs, for example of a containment vessel, the thickness of the substrate and the diameter of the second through-hole can be several centimeters.

[0086] In the case of an airbag igniter and / or a seat belt tensioner and / or a gas generator, the functional element is a metal pin fixed in the through-hole, similar to a ground pin soldered to the substrate. These metal pins are typically coated with gold at least in a subregion along their axis. The gold coating provides the effect of long-term resistance to corrosion and long-term contact sensitivity. The metal pins are typically coated with gold in their end region. In this way, the region of the metal pin within the plug connection for the ignition device during assembly is preferably gold-plated. In this way, the transfer resistance in the plug-in contact can be reduced.

[0087] In an advantageous embodiment, at least two metal pins are connected to one another in an electrically conductive manner by an ignition bridge on the substrate side facing the propellant. The ignition bridge can be formed by the ignition wire already described, the metal pin on this side typically not having any protrusion beyond the substrate surface located on this side.

[0088] As already mentioned, the microstructure in the soldering region can be characterized by the average roughness Ra and the average surface roughness Rz. In tests likewise exemplary embodiments, an existing standard substrate without the introduction of a microstructure was compared with a series of substrates with the introduction of a microstructure at least in the soldering region. The results are compiled in Table 1.

[0089] .

[0090] Five different substrates were extracted from mass production in different cases and measured for the Ra and Rz values. The tactile measurement by means of a Hommel tester known to the person skilled in the art was used as a measurement method. From the values determined in the different cases, the arithmetic mean value and the resulting standard deviation are likewise given in Table 1.

[0091] In the column entitled "Without microstructure", the results of a substrate without the introduction of a microstructure are shown. It goes without saying that even such a substrate is not completely smooth, so that the Ra and Rz values are not equal to 0. This non-smoothness can be seen with the naked eye, for example in the form of scratches or indentations on the surface. These scratches or indentations are particularly randomly distributed over the surface of the substrate and can have arisen, for example, when the substrate was transported, in particular when in contact with the walls of the transport container and / or when the substrates collided with one another. In the case of the substrate without the introduction of a microstructure, the average value of Ra is 0.16 μm and the standard deviation of 0.06 μm.

[0092] In the column entitled "With microstructure", the measured values of Ra and Rz are compiled for substrates in which a microstructure has been introduced at least in the soldering region by means of a pulsed IR diode laser. Depending on the laser power introduced by the laser, the different production conditions differ in that the laser power is related to the integral of the laser power over time, and thus to the pulse width and the maximum power of the pulses, corresponding to parameters 1 to 5. In the column of parameter 1, the lowest laser radiation is radiated, in the column of parameter 2 the laser power is greater, and so on up to the column of parameter 5. In particular, the radiated laser power can also be set by the overlap of individual laser pulses and / or their pulse frequency.

[0093] It can be observed that all the values of Ra and Rz, i.e. all the values from each individual measurement, are much greater than those of the substrate without a microstructure. This also applies in particular to the respective average values of Ra and Rz. It is thus evident that the substrate provided by the present application with an introduced microstructure is clearly distinguished from the prior substrate without the introduction of a microstructure.

[0094] Ra values of approximately 0.3 μm to 10 μm can be achieved using a pulsed laser. Tests using a continuous wave (CW) laser were also carried out. In this way, Ra values of 0.3 μm to approximately 100 μm can even be achieved.

[0095] These large roughness values indicate that, at high deposition laser powers, not only have the organic and / or carbon-containing impurities and / or metal oxide layers been removed from the substrate surface, but also the thermal and / or other laser-induced reshaping described above likewise plays a role.

[0096] As mentioned above, the presence of microstructures in the soldering region has the effect that, in particular by the interaction between the solder and the microstructures, an improved soldered connection between the second metal pin, the ground conductor and the base body is provided as offered by the present invention. The quality of this soldered connection can be assessed by means of a bending test. In this case, the soldered metal pin is clamped and mechanically bent in both directions to an angle of about 45° to the axis of the metal pin in each case. In this case, the pivot point of the bending is as close as possible to the surface of the base body. This bending test is carried out on a test quantity of components, for example 5000 base bodies with soldered ground pins.

[0097] The results of this bending test for base bodies without microstructures and for base bodies with microstructures are listed in table 2, to be precise for a series of tests under critical conditions in each case.

[0098] .

[0099] As indicated in the test conditions column, a series of tests were carried out on base bodies which were contaminated with usual metal impurities, here aluminium. This took the form of a powder layer mixed with organic constituents which were located on the base body. This test simulated the occurrence of metal particle contamination, for example which usually occurs during the production process. This usually involves a surface machining step. The vibratory grinding which can be used is defined in DIN 8589 and is referred to there as vibratory finishing, since it does not always involve a grinding process, but according to the method it can also be milling or polishing. Vibratory grinding in a drum is also referred to as tumbling. In this case, so-called tumbling stones were used and it was possible for abraded metal to be deposited on the base bodies produced.

[0100] In another series of tests, a test quantity of base bodies was kept in an oil bath for 21 days. This was a mineral machine oil. This test simulated the contamination of lubricants during the production process.

[0101] Both test conditions represent limiting cases of adverse production conditions which can occur in industrial mass production. These tests are suitable for quality assessment of process reliability. A test quantity of base bodies produced in each case without microstructures was then soldered to ground pins. Further test quantities under the same production conditions were provided with microstructures in the soldering region by means of a pulsed diode laser, subsequently soldered there to ground pins. The respective test quantities were subjected to a bending test.

[0102] As can be seen from table 2, the defect rate for the components without microstructures was 123 per 5000 components or 3 per 5000 components. In table 2, NOK stands for “not ok”, so the number of components which did not pass the bending test described above is given. It is interesting that the metal contamination seems to be more fatal for the soldered connection than the oil enrichment.

[0103] In contrast, none of the components provided with the microstructured test quantity had any defective components. In other words, all of the components investigated passed the bending test, independently of the contamination. This proves that the presence of the microstructure provided by the application leads to a significant improvement in the production reliability of the brazed connection and thus significantly improves the producibility of such feedthroughs. A series of tests as in Table 2 were carried out on substrates of the vehicle-processed components, stamped and cold-formed substrates. It was thereby confirmed that substrates with microstructures in the brazing region have reliable brazed connections, independently of the manufacturing method of the substrate. BRIEF DESCRIPTION OF DRAWINGS

[0104] The application is explained in more detail below on the basis of the drawings. The drawings are not to scale and the embodiments represented are schematic. The drawings also represent exemplary embodiments given by way of example.

[0105] Figure 1 A known ignition device is shown, which comprises a feedthrough element according to the prior art, without microstructure in the brazing region.

[0106] Figure 2a A cross-section through a feedthrough element according to the application is shown, parallel to its axial central axis.

[0107] Figure 2b A plan view of a surface of a feedthrough element according to the application is shown.

[0108] Figure 3 A detail of a cross-section through a feedthrough element according to the application is shown, parallel to its axial central axis, with a microstructured brazing region.

[0109] Figure 4 The metal structure of a substrate in a wet-chemical treatment process corresponding to the prior art is shown schematically.

[0110] Figure 5 The metal structure of a substrate according to the application in the course of its processing is shown schematically.

[0111] Figure 6a A photograph of a detail of the microstructure is shown.

[0112] Figure 6b A detail corresponding to the conversion into a graph is shown. Figure 6a

[0113] Figure 7 The function of the microstructure as a solder stop is shown schematically.

[0114] Figure 8 A detail of a cross-section through a substrate according to the application is shown schematically, with a meniscus of a brazed connection.​

[0115] Figure 9 A substrate according to the invention is shown, which has a microstructure over the entire surface area. Detailed Implementation

[0116] exist Figure 1 The image shows an ignition device known in the prior art for pyrotechnic protection devices, exemplified here as an airbag igniter. Therefore, Figure 1 A cross-sectional view of the feedthrough element is shown in particular. The feedthrough element comprises a metal carrier portion having a base (1) having a basic disc-shaped form. The feedthrough element is also commonly referred to as a manifold element or simply a manifold. In the through-hole (4) of the base (1), metal pins (5) are also configured as functional elements. In this case, the through-hole (4) protrudes from the base (1). The metal pins (5) are used to contact the ignition bridge (9) to provide current, through which the propellant (25) sealed in the completed igniter is ignited. The current feedthrough in the through-hole (4) is particularly constructed as a glass-metal feedthrough, wherein glass is used as a fixing material (10) between the metal pins (5) and the wall of the through-hole (4) in the metal base (3). High-performance polymers or other suitable materials can also be used in the through-hole.

[0117] exist Figure 1 In the example shown, the through hole (4) is arranged eccentrically relative to the axial central axis of the substrate (1). This achieves the effect that even if the radius of the substrate (1) is small, there is sufficient space to fix the second metal pin (6). The second metal pin (6) is flush-welded to the substrate (1) by a brazing connector and thus serves as a grounding pin (also called a grounding pin (6)). The described brazing filler metal, particularly a metallic brazing filler metal (especially a hard brazing filler metal), is used as the brazing filler metal (7). The brazing filler metal (7) forms a meniscus between the substrate surface and the grounding pin (6). The brazing filler metal (7) covers the surface area of ​​the substrate (2), thereby forming a brazing region. The brazing filler metal (7) covers the microstructure in the brazing region. This applies to all figures and exemplary embodiments. The diameter of the brazing region corresponds to the diameter of the brazing filler metal (7). For manufacturability reasons, the brazing filler metal (7) must not enter the through hole (4) and / or be located on the insulating material (10) of the latter. Therefore, the grounding pin (7) must maintain a minimum distance from the through hole (4). Similarly, the solder (7) should be prevented from wetting the outer wall of the substrate (1). Therefore, a minimum distance should be maintained between the grounding pin (6) and the periphery of the substrate (1). Even if the minimum distance is maintained, statistical deviations and / or slight errors in the production process may cause this undesirable expansion of the solder (7), which leads to defective parts and thus non-conforming components.

[0118] In comparison, Figure 2aA cross section through the feedthrough element according to the application is shown, which is parallel to its axial center axis and through it. The base body (1) has a first surface (11) (here: upper side) and a second surface (12) (here: lower side), which in many embodiments extends parallel to the first surface. The upper side (11) usually faces the propellant (25); on the lower side (12) the electrical contacts are usually established. Figure 2b A plan view of the lower side (12) is shown in the middle.

[0119] The disc-shaped metal base body (1) has a through-hole (4) through which the metal pin (5) is guided. The through-hole (4) can be punched out of the base body (1). In this example, the outer contour of the base body (1) is also punched out of a metal strip, so here the entire base body (1) represents a punched part. However, the application can also be implemented and also encompasses that the base body is made of wire material by cold forming. In the through-hole (4), the metal pin (5) is fixed as a first pin (also called contact pin) and electrically insulated from the base body (3) by a glass material (10). The first metal pin (5) is hermetically glass-sealed in the first through-hole (4) of the metal base body (1). The glass material (10) of the glass-metal feedthrough is completely surrounded by the material of the base body (1), which represents the outer conductor. The glass material (10) has a lower coefficient of thermal expansion than the metal of the base body (1), so that, in the cooling process after soldering the metal pin (5) into the glass material (10), the base body (1) exerts a permanent mechanical pressure on the latter and the glass-metal feedthrough when the base body (1) shrinks onto the glass material. In this way, a particularly tight and mechanically stable connection is formed between the metal pin (5), the glass material (10) and the base body (1). This structure is called compression glazing-in and should be preferred, for example, for airbag igniters. The use of glass-ceramic materials and / or high-performance polymers is also possible and encompassed by the application.

[0120] The second metal pin (6) is connected as a ground pin to the base body (1) in the soldering area (7) by a soldering connection. At least in the soldering area (7), the base body (1) has a microstructure (8), which in a manner corresponding to this embodiment is distinguished by recesses in the base body surface. Between the recesses there are webs having a lower depth compared to the bottoms of the recesses, which represent the edges of the individual recesses of the microstructure (8). In particular, these edges represent solder dams for the solder. This means, inter alia, that the flow of the solder during the melting process is controlled by the microstructure (8). As described above, the solder (7) covers and interacts with the microstructure in the soldering area. By means of the microstructure, the soldering area with the solder (7) is also limited in diameter (d).

[0121] The feedthrough element (1) and its manufacturing method according to the present invention make it particularly possible to implement ignition devices that are less complex than those known in the prior art, mainly because the presence of the microstructure (8) allows for control of the diameter (d) of the brazing area (7). Therefore, the number of defective parts in large-scale industrial production is reduced, thereby reducing the amount of scrap.

[0122] Figure 3 It shows Figure 2a Details of the area of ​​the brazed connector. The brazed area with brazing filler metal (7) can be seen again. The brazing filler metal forms a meniscus with radius (r) on the wall relative to the grounding pin (6). The brazed area (7) has a diameter (d). Microstructures (8) exist in the brazed area, and possibly outside the brazed area. According to the invention, the brazed connector between the metal pin (6) and the substrate (1) is located where the microstructure exists. For the purposes of the invention, it is also feasible for the microstructure to be on the entire lower side (12) of the substrate (1). There is usually a gap filled with brazing filler metal (i.e., the so-called brazing filler gap (70)) between the upper side of the grounding pin (6) and the surface of the substrate (1), the gap having a brazing filler gap width. Advantageous brazing gap widths are also between 10 μm and 70 μm.

[0123] Figure 4 The metallic structure of the substrate corresponding to the wet chemical treatment process in the prior art is schematically shown. Details of the substrate are shown in different cases. In this example, the substrate is composed of chromium-containing austenitic steel. The metallic microstructure of the substrate includes an austenitic phase (101) and a martensitic phase (102), the manufacture of which can be facilitated in particular by the deformation process of the substrate during its production. The basic state of such a substrate (1) is shown in the figure above. The surface of the substrate (1) is covered with a layer of chromium oxide (40), in which iron oxide regions (41) may be present. In particular, the iron oxide regions may be arranged like rust spots on the surface of the substrate.

[0124] By means of a process corresponding to the prior art previous manufacturing method, the substrate is subjected to an etching treatment in a mixed acid bath. The result of this etching process is represented in the middle illustration. It can be seen that, although most of the chromium oxide layer has been removed, regions (40) remain. Similarly, iron oxides (41) remain after etching. Similarly, etching generally causes a selective corrosion of the individual phases of the metal microstructure. Thus, in this illustration, the martensite in particular is affected by a selective corrosion in regions (103). As a rule, martensite is attacked more by the acid than ferrite, and ferrite in turn is attacked more than austenite. Another form of damage is the grain boundary corrosion in regions (104). There, the acid attack seems to cause cracks at the grain boundaries of the same phase of the metal microstructure. Similarly, regions (105) are affected by a pitting corrosion, which can lead to depressions in the form of pores in the surface of the substrate.

[0125] In the lowermost part of the illustration, the state of the substrate after ageing in atmospheric conditions in the conventional method is shown. The main effect is the re-oxidation of the metal surface, which can be manifested by a layer of iron oxides (410) on the surface. Similarly, in the region of the grain boundary corrosion (104), the chromium fraction in the metal microstructure can be depleted, which can weaken it and / or change its chemical properties. Of course, regions with the chromium oxide layer (40) and the layer of iron oxides (41) remain after etching. Overall, the corrosion on the substrate leads to a rough surface, the Ra and Rz values of which deviate from 0. However, these structures are arranged at random and they do not form a microstructure. Similarly, the depressions on the surface are smaller and deeper than the microstructure according to the application. The Ra and Rz values of the substrate according to the conventional production method correspond to the values reproduced in Table 1.

[0126] In comparison with the conventional method, in the Figure 5 The metal structure of the substrate during the physical treatment corresponding to the application is shown schematically in the upper part of Figure 5 The basic state of the substrate (1) is again shown in the upper illustration. This corresponds to the basic state in Figure 4

[0127] In the lower part of the illustration, the state of the substrate after the physical treatment corresponding to the application is shown. The main effect is the re-oxidation of the metal surface, which can be manifested by a layer of iron oxides (410) on the surface. Similarly, in the region of the grain boundary corrosion (104), the chromium fraction in the metal microstructure can be depleted, which can weaken it and / or change its chemical properties. Of course, regions with the chromium oxide layer (40) and the layer of iron oxides (41) remain after etching. Overall, the corrosion on the substrate leads to a rough surface, the Ra and Rz values of which deviate from 0. However, these structures are arranged at random and they do not form a microstructure. Similarly, the depressions on the surface are smaller and deeper than the microstructure according to the application. The Ra and Rz values of the substrate according to the conventional production method correspond to the values reproduced in Table 1. Figure 5 ​The intermediate illustration shows the state of the substrate after the introduction of the microstructure (8), which is generated by laser structuring. It has been found that no selective corrosion, grain boundary corrosion, or pitting corrosion was observed. Similarly, the chromium oxide layer (40) and the iron oxide layer (41) were removed, and therefore they are not present in this illustration. Instead, the structure shown results in a very horizontal and uniform surface divided by webs (80). The webs have a web width (b), which in the illustration can be from about 0.5 μm to about 8 μm. The web height corresponds to the hole depth (t) of the recess between the webs (80). In this example, the hole depth corresponds to about 4 μm to 8 μm. The spacing between the webs corresponds to the hole width (l). In this example, the spacing is about 50 μm. However, the present invention provides that this spacing can be set, particularly within the aforementioned advantageous range. The combination of the webs (80) and the recesses located therebetween and / or defined by the latter represents the microstructure provided by the present invention. The web height is particularly greater than the recesses in the substrate, which are defined by corresponding... Figure 4 This is produced through corrosion. (In the corresponding...) Figure 5 In an exemplary embodiment, the values ​​of Ra and Rz may also specifically assume the values ​​reproduced in Table 1.

[0128] exist Figure 5 The figure below again shows the state of the substrate after aging under atmospheric conditions. The dominant process is re-oxidation. It has been found that at least a near-ideal passivation film or layer (400) forms particularly surprisingly in the recess between the webs. As observed, this layer is typically very thin. For representative reasons, cases relating to the dimensions of the webs (80), etc., are not shown. In this example, it is approximately 3 nm thick. This means that the passivation layer can be thinner than the height of the webs and / or the height of the recess (t). The composition of the passivation layer depends on the metal of the substrate. In this example with a chromium-containing steel substrate, the layer (400) contains CrO. X Particularly preferably, the layer contains CrO X (OH) 2-X • nH2O or CrO X (OH) 2-X • Composed of nH2O.

[0129] Figure 6a A detailed photograph of the substrate (1) manufactured by the method is shown, in which microstructures are introduced by laser processing. The structure of the microstructures in the form of a mesh can be clearly seen. The lines of the mesh are formed by webs (80), and the openings of the mesh are formed by recesses.

[0130] exist Figure 6b For the sake of explanation, Figure 6a The photographs in the image have been converted into a graphic format. The recesses of the microstructure (8) have a pore width (l), which can be, for example, 70 μm.

[0131] Figure 7 A detail of the base body according to the application in the end region of the soldering region is shown schematically, in particular a cross section through the region of the microstructure (8) in the soldering region. Here, the wetting of the surface of the base body (1) ends in the region of the microstructure. Even if, as described above, the metallic solder (7) forms a meniscus with respect to the ground pin (6), at the end of the soldering region there is a contact angle or wetting angle φ with respect to the surface region of the base body. The individual elements of the microstructure (8) limit the flow of the solder (7). It is assumed that the conditioning of the surface material of the base body, as described above, acts together with the surface tension of the molten metallic solder. In this way, the spreading of the metallic solder (7) can be limited. It also seems possible that the variation of the structure within the microstructure (8) acts together with the surface tension of the molten metallic solder, so that the contact angle or wetting angle φ becomes larger and, in this way, the flow of the molten solder is stopped, for example at the webs of the microstructure. Also combinations of these effects are considered in this.

[0132] In Figure 8 A detail of the base body according to the application in the region of the soldered ground pin (6) and in the partial region of the soldering region (7) is shown schematically. The metallic solder (7) forms a solder meniscus with respect to the ground pin (6), which draws itself onto the ground pin (6). For reasons of simplification, the microstructure is not shown here. Between the surface of the base body (1) and the head region of the ground pin (6) there is a solder gap (70) with a solder gap width (s). The solder meniscus has a radius (r), which is shown by the circle drawn with the dashed line. As described above, the present application makes it possible for the radius r to be reduced in a controlled manner and / or compared to the prior art. This makes it possible for the diameter (d) of the soldering region (7) to be small and controlled. In particular, as described above, the variation of the radius (r) and the diameter (s) of the soldering region is reduced by the microstructure (8). With less solder it is possible to improve the production reliability, which in turn leads to a significant reduction in the costs of production of the base body according to the application.

[0133] Figure 9 A base body (1) according to the application is shown schematically here in the form of a feedthrough for an airbag igniter and / or a seat belt tensioner and / or a gas generator. The elements thereof have been described above. It is apparent that the base body has a microstructure (8) on the entire surface region on one surface. As described above, it is possible to prevent corrosion of the metallic surface, for example corrosion produced by previously used wet-chemical methods, by means of the laser-based machining method. In particular, the base body (1) shown has a homogeneous passivation layer (400). In particular, such a base body (1) can have a greater mechanical strength and be more resistant to corrosion than previously known base bodies.

[0134] The application can also be summarized by the following statements. The content of the statements and how they depend on each other also form part of the entire disclosure of the specification. The person skilled in the art is able to further develop the specification and / or the statements.

[0135] Statement 1. A base body for a feedthrough element, comprising: a metal base body; at least one through-hole for accommodating a functional element in a fixing material, in particular an electrically insulating fixing material; and at least one conductor which is electrically connected to the base body by means of a solder connection, wherein the solder connection comprises a metal solder; wherein the metal solder covers a surface region of the base body, thereby forming a solder region on the surface of the base body; wherein the base body has a microstructure at least in the solder region, the microstructure comprising at least recesses in the surface of the base body; and wherein the metal solder covers the microstructure in the solder region.

[0136] 2. The base body according to statement 1, wherein the microstructure is a solder dam of the metal solder.

[0137] 3. The base body according to at least one of the preceding statements, wherein the recesses of the microstructure form a substantially regular pattern.

[0138] 4. The base body according to at least one of the preceding statements, wherein the recesses of the microstructure are arranged adjacent to each other and / or they overlap at least in certain regions; preferably, the microstructure forms a grid in the form of dots and / or a structure in the form of a mesh and / or a structure in the form of scales in a plan view.

[0139] 5. The base body according to at least one of the preceding statements, wherein the recesses of the microstructure are laser-structured regions, in particular laser-ablated regions, and / or regions which are locally reshaped in a laser-induced manner, and / or regions which are locally reshaped by a laser-induced pressure effect, in the surface of the base body.

[0140] 6. The base body according to at least one of the preceding statements, wherein the microstructure is in the form of grooves and / or the microstructure comprises recesses having a circular and / or elliptical and / or substantially rectangular diameter; preferably, the recesses are in the form of craters and / or in the form of cups.

[0141] 7. The substrate according to at least one of the preceding statements, wherein the depth of the recesses of the microstructure is essentially up to 70 pm, in particular up to 50 pm, in particular from 0.7 pm to 70 pm, in particular from 0.7 pm to 50 pm, preferably from 0.7 pm to 20 pm, particularly advantageously from 1 pm to 10 pm, most particularly advantageously from 2 pm to 10 pm, measured from the surface of the substrate.

[0142] 8. The substrate according to at least one of the preceding statements, wherein the substrate has an average roughness Ra≥ 0.35 pm and / or an average surface roughness Rz≥ 1 pm in the region of the microstructure; preferably, Ra is in the range from 0.35 pm to 15 pm and / or Rz is in the range from 1 pm to 50 pm, in particular Rz is in the range from 1 pm to 15 pm.

[0143] 9. The substrate (1) according to at least one of the preceding statements, wherein the recesses of the microstructure are formed such that webs are present between the individual recesses.

[0144] 10. The substrate (1) according to at least one of the preceding statements, wherein the recesses have a diameter of from 10 pm to 200 pm, preferably from 20 pm to 150 pm, particularly preferably from 80 pm to 150 pm, most particularly preferably from 80 pm to 150 pm, measured at the narrowest point.

[0145] 11. The substrate (1) according to at least one of the preceding statements, wherein at least in the recesses, the surface of the microstructure is free of organic material and / or free of carbon; preferably, at least in the recesses, at least a pure metal surface or a substantially homogeneous oxide layer, advantageously a thin oxide layer, is present, the thickness of which is preferably less than 10 nm, particularly advantageously from 1 nm to 6 nm.

[0146] 12. The substrate (1) according to at least one of the preceding statements, wherein at least in the regions in which the microstructure is present, the substrate comprises or consists of a chromium-containing metal, in particular a chromium- and / or nickel-containing steel, including a chromium- and / or nickel-containing high-grade steel; and, at least in the recesses of the microstructure, the surface is covered by a homogeneous layer comprising CrO X and / or NiO X ; this homogeneous layer preferably comprises CrO X (OH) 2-X • nH2O and / or NiO X (OH) 2-X • nH2O or consists of CrO X(OH) 2-X • nH2O and / or NiO X (OH) 2-X • nH2O.

[0147] 13. The base according to at least one of the preceding statements, wherein the metal solder is a hard solder; preferably, the metal solder material is essentially free of palladium.

[0148] 14. The base according to at least one of the preceding statements, wherein the metal solder electrically connecting the conductor with the base forms a solder meniscus at the transition to the surface of the base, the solder meniscus having a radius of at most 0.40 mm.

[0149] 15. The base according to at least one of the preceding statements, wherein between the surface of the conductor facing the base and the microstructured surface of the base there is a solder gap filled with metal solder, the metal solder having a solder gap width of at most 100 pm, preferably 3 nm to 100 pm, particularly preferably at most 80 pm or at most 70 pm, particularly preferably 3 nm to 70 pm, measured from the lowest point of the recess of the microstructure.

[0150] 16. The base according to at least one of the preceding statements, wherein the microstructure increases the force required for shearing and / or pulling out the grounding pin compared to a feedthrough element (1) without microstructure; preferably, the force for shearing and / or pulling out is increased by at least 10%.

[0151] 17. The base (1) according to at least one of the preceding statements, the soldering region having a maximum diameter, measured parallel to the surface of the base, which is at most twice the diameter of the grounding pin.

[0152] 18. The base (1) according to at least one of the preceding statements, wherein the shortest distance between the outer circumference of the through-hole and the outer circumference of the conductor, measured at the point of connection with the base, is at most 2.5 mm.

[0153] 19. The base (1) according to at least one of the preceding statements, wherein the shortest distance between the outer circumference of the base and the outer circumference of the conductor, measured at the point of connection with the base, is at most 2.5 mm; preferably, this distance is 2.0 to 2.4 mm.

[0154] 20. The base body for manufacturing an airbag igniter or a seat belt tensioner according to at least one of the preceding statements, wherein in the at least one through-hole a conductor is arranged as a functional element in an electrically insulating fixing material; and the conductor, which is in electrically conductive connection with the base body, is formed as a ground pin, which is flush brazed to the base body in a brazing area.

[0155] 21. The base body according to statement 20, wherein the diameter of the ground pin is 1 mm ± 0.02 mm, and at the transition to the surface of the base body, the radius of the meniscus of the metal braze is less than 0.40 mm, preferably less than 0.36 mm, particularly preferably less than 0.30 mm, most particularly preferably less than 0.22 mm.

[0156] 22. The base body according to at least one of statements 20 and 21, wherein the volume of the metal braze is less than 0.16 mm 3 , preferably less than 0.13 mm 3 , particularly preferably less than 0.10 mm 3 , most particularly preferably less than 0.07 mm 3 .

[0157] 23. The base body according to at least one of statements 20 to 22, wherein the diameter of the brazing area is 1 mm to 2.5 mm, particularly 1 mm to 2.0 mm. 24. The feed-through element with a base body according to at least one of statements 1 to 23, wherein in the at least one through-hole at least one functional element is arranged in an electrically insulating fixing material.

[0158] 25. The feed-through element according to statement 24, wherein the functional element is an electrical conductor, particularly an electrical conductor in the form of a pin and / or a waveguide and / or a hollow conductor and / or an optical conductor and / or a thermocouple.

[0159] 26. The feed-through element according to statements 24 and / or 25, wherein the base body has exactly one through-hole, in which a electrical conductor is arranged in a glass, or a glass-ceramic material, or a ceramic, or a plastic.

[0160] 27. A plurality of base bodies or feed-through elements for manufacturing an airbag igniter or a seat belt tensioner or a gas generator according to at least one of the preceding statements, comprising 5000 test quantities of base bodies or feed-through elements, wherein the defect rate per thousand of the ground pin bending test is less than 0.5.

[0161] 28. A plurality of base bodies or feed-through elements for manufacturing inflator igniters or seat belt tensioners or gas generators according to at least one of the preceding statements, comprising 1000 test quantities of base bodies or feed-through elements, wherein the standard deviation of the average value of the diameters of the soldering areas in this test quantity is in the range of 0% to 6% of the average diameter of the soldering areas in this test quantity.

[0162] 29. A method for manufacturing a base body of a feed-through element, comprising the following method steps: - providing a metal base body having a predetermined thickness and a predetermined outer contour, the metal base body having two substantially opposite surfaces (31, 32); - generating at least one through-hole (4, 20) in the base body (3); - microstructuring at least one region of the surface of the base body in order to introduce recesses in the surface of the base body; - providing at least one conductor (5, 6); - soldering the at least one conductor (5, 6) to the base body with a metal solder in the region in which the microstructure is present, the metal solder being molten during the soldering process, wherein the flow of the molten solder is prevented and / or limited at least by the elements of the microstructure and the region of the surface of the base body covered by the solder forming the soldering area, so that the at least one conductor (5, 6) is in electrically conductive connection with the base body in the soldering area.

[0163] 30. The method according to statement 29, wherein the microstructure is generated by removing material from the surface of the base body, preferably by grinding the base body, particularly preferably by a method of pressing into the base body.

[0164] 31. The method according to at least one of statements 29 and 30, wherein laser structuring is used for generating the microstructure.

[0165] 32. The method according to statement 31, wherein the microstructuring is at least partially carried out by laser ablation and / or laser desorption, wherein surface material of the base body, in particular an oxide layer and / or organic impurities, is removed under the action of laser radiation, exposing a substantially bare metal surface of the base body which reflects the incident laser radiation; in particular, the exposed bare metal surface limits the depth of the microstructure.

[0166] 33. The method according to at least one of statements 31 and 32, wherein During laser structuring, the surface material of the substrate is reshaped by means of laser radiation, in particular by locally heating, in particular locally melting, the material of the substrate and / or by laser-induced pressure effects, wherein at least in the vicinity of the substrate the laser radiation locally heats a gaseous atmosphere, in particular locally ignites a plasma, thereby forming pressure waves which deform the surface of the substrate.

[0167] 34. The method according to at least one of the statements 29 to 33, wherein the microstructure gives a structure in the form of a dot and / or rectangular grid and / or a grid and / or a structure in the form of a scale in a plan view.

[0168] 35. The method according to at least one of the statements 29 to 34, wherein impurities and / or organic substances and / or carbon-containing substances and / or oxides on the surface of the substrate are removed when the microstructure is generated.

[0169] 36. The method according to at least one of the statements 29 to 35, wherein after the microstructure is generated and before soldering onto a conductor, the substrate is covered at least in the region of the microstructure with a substantially homogeneous and thin oxide layer; preferably, the oxygen for forming the oxide layer originates from the ambient atmosphere.

[0170] 37. The method according to at least one of the statements 29 to 36, wherein after the microstructure is introduced, the substrate is substantially free of organic material and / or of carbon at least in the recesses; preferably, there is a pure metal surface or a substantially homogeneous and preferably thin oxide layer present at least in the recesses, the thickness of which is preferably less than 10 nm, in particular 1 nm to 6 nm.

[0171] 38. The method according to at least one of the statements 29 to 37, wherein the substrate comprises or consists of a chromium-containing metal, in particular a chromium-containing steel, including a chromium-containing high-grade steel, at least in the region in which the microstructure is present; and, at least in the recesses of the microstructure, the surface is covered by a homogeneous layer comprising CrO X and / or NiO X ; the homogeneous layer preferably comprises CrO X (OH) 2-X • nH2O or consists of CrO X (OH) 2-X • nH2O and / or comprises NiO X (OH) 2-X • nH2O or consists of NiO X (OH)2-X • nH2O composition.

[0172] 39. The method according to at least one of statements 29 to 38, wherein hard solder is used as the metal solder; advantageously, the metal solder is essentially free of palladium; prior to brazing, the metal solder is advantageously placed in the form of a ring around the conductor, thus, during brazing, the metal solder flows into the microstructure and forms the brazing region, wherein in the metal solder-filled region of the microstructure (8) a solder gap exists between the conductor (6) and the surface of the base body.

[0173] 40. The method according to at least one of statements 29 to 39, wherein the microstructure is introduced into the base body with a depth of at most 70 pm, essentially 0.7 pm to 70 pm, advantageously 0.7 pm to 20 pm, particularly advantageously 1 pm to 10 pm, most particularly advantageously 2 pm to 10 pm, measured from the surface of the base body.

[0174] 41. The method according to at least one of statements 29 to 40, wherein the microstructure is introduced into the base body with an average roughness Ra≥ 0.35 pm and / or an average surface roughness Rz≥ 1 pm; advantageously, Ra is in the range of 0.35 pm to 15 pm and / or Rz is in the range of 1 pm to 50 pm; in particular, Rz is in the range of 1 pm to 15 pm.

[0175] 42. Use of the base body and / or the feedthrough element according to at least one of statements 1 to 23 in an electrical feedthrough element.

[0176] 43. Use of the base body and / or the feedthrough element according to at least one of statements 1 to 23 in or as part of and / or region of a pyrotechnic trigger and / or an airbag igniter and / or a seat belt tensioner and / or a gas generator and / or a sensor and / or an actuator and / or a large feedthrough and / or a transistor outline package and / or a battery housing and / or a capacitor housing.

[0177] As mentioned above, the base body (1) according to the application has significant advantages over previously known base bodies. On the one hand, the control of the soldering area has the effect that the base body according to the application has a lower variance in terms of the diameter (d) of the soldering area, the radius (r) of the solder meniscus and the solder gap width (s). This means that the soldering connection between the base body (6) and the grounding pin (6) is formed more reliably. As a result, in particular in industrial processes, the base body (1) according to the application can be produced more efficiently; in particular, the number of rejects is reduced. It is also possible to reduce the amount of solder used. Similarly, the control of the diameter (d) of the soldering area (7) makes it possible for the diameter (d) to be smaller, and thus for the grounding pin (6) to be arranged closer to the base body and / or the circumference of the through-hole (4). As a result, the diameter of the base body (1) can be chosen to be smaller; thus, a miniaturized base body can be realized. Furthermore, the base bodies according to the application have no or at least significantly less corrosive damage to their metal microstructure. Furthermore, they can be covered by an efficient, in particular uniform, passivation layer. This increases their mechanical load capacity and / or their corrosion resistance. Components produced from them benefit in terms of improved service life and / or reliability.

[0178] List of names 1 base body 2 cover 4 through-hole 5 functional element, first metal pin 6 conductor, second metal pin, grounding pin 7 metal solder, soldering area 8 microstructure 9 bridge line 10 electrically insulating fixing material 11 surface of the base body, upper side 12 surface of the base body, lower side 25 propellant 40 chromium oxide 41 iron oxide 70 solder gap 80 web 101 austenitic phase 102 martensitic phase 103 selective corrosion 104 grain boundary corrosion 105 pitting corrosion 400 passivation film 410 reformed iron oxide d diameter of the soldering area r radius of the meniscus s solder gap width b web width t recess height l hole width

Claims

1. A substrate for a feedthrough element, comprising: Metal matrix (1); At least one through hole (4) for accommodating a functional element (5) in an electrically insulating fixing material (10); and At least one conductor (6) is electrically connected to the substrate via a brazing connector. The brazing connectors mentioned above include brazing filler metal (7); The metal brazing filler metal (7) covers the surface area of ​​the substrate (1), thereby forming a brazing area on the surface of the substrate; The substrate (1) has a microstructure (8) at least in the brazing region, the microstructure including at least a depression in the surface of the substrate; At least one conductor (1) electrically connected to the substrate is formed as a grounding pin (6), and the end face of the grounding pin is brazed flush with the substrate (1) in the brazing area (7); and The substrate has an average roughness Ra in the region of the microstructure (8) ranging from 0.35 μm to 15 μm and an average surface roughness Rz ranging from 1 μm to 50 μm. In the recess, there is at least a pure metal surface or a substantially homogeneous and thin oxide layer (400) with a thickness of less than 10 nm, particularly 1 nm to 6 nm. The recesses of the microstructure (8) are formed such that there are webs between the recesses, the webs being covered by an oxide layer different from the oxide layer on the surface of the recess; or the webs are covered by an oxide layer and the recesses have substantially exposed metal surfaces. as well as The brazing filler metal is a hard brazing filler metal; the palladium content in the brazing filler metal is less than 2000 ppm.

2. The matrix (1) according to claim 1, wherein The microstructure (8) is a brazing stop for the brazing metal (7).

3. The matrix (1) according to at least one of the preceding claims, wherein The indentations of the microstructure (8) form a basically regular pattern.

4. The matrix (1) according to at least one of the preceding claims, wherein The recesses of the microstructure (8) are arranged adjacent to each other and / or they overlap at least in some areas; preferably, the microstructure forms a grid in the form of dots, and / or a mesh in the form of grids, and / or a scale in the form of scales in a plan view.

5. The matrix (1) according to at least one of the preceding claims, wherein The recesses in the microstructure include laser-structured regions on the surface of the substrate, particularly laser-ablated regions, and / or regions that are locally re-thermally shaped by laser induction, and / or regions that are locally reshaped by laser-induced pressure effects.

6. The matrix (1) according to at least one of the preceding claims, wherein The microstructure (8) is in the form of a groove and / or the microstructure includes a recess with a circular and / or elliptical and / or rectangular diameter; preferably, the recess is in the form of a pit and / or a cup.

7. The matrix (1) according to at least one of the preceding claims, wherein Measured from the surface of the substrate, the depth of the recess of the microstructure (8) is substantially up to 70 μm, preferably from 0.7 μm to 70 μm, more preferably from 0.7 μm to 20 μm, particularly preferably from 1 μm to 10 μm, and most particularly preferably from 2 μm to 10 μm.

8. The matrix (1) according to at least one of the preceding claims, wherein Rz is in the range of 1 μm to 15 μm.

9. The matrix (1) according to at least one of the preceding claims, wherein Measured at its narrowest point, the diameter of the depression is 10 μm to 200 μm, preferably 20 μm to 150 μm, particularly preferably 80 μm to 150 μm, and most particularly preferably 80 μm to 150 μm.

10. The substrate (1) according to at least one of the preceding claims, wherein at least in the region where the microstructure (8) exists, the substrate comprises or is composed of a chromium-containing metal, particularly chromium-containing steel, including high-grade chromium-containing steel; and, at least in the recesses of the microstructure, the surface is composed of CrO X and / or NiO X The homogeneous layer is covered; the homogeneous layer preferably includes CrO. X (OH) 2-X • nH2O and / or NiO X (OH) 2-X •nH2O or CrO X (OH) 2-X • nH2O and / or NiO X (OH) 2-X •Composition of nH2O.

11. The substrate (1) according to at least one of the preceding claims, wherein the metal solder that electrically connects the conductor to the substrate forms a meniscus at the transition to the surface of the substrate, the meniscus having a radius of up to 0.40 mm.

12. The substrate (1) according to at least one of the preceding claims, wherein there is a solder gap (70) filled with metal solder between the surface of the conductor (6) facing the substrate and the microstructured surface (8) of the substrate, wherein the metal solder has a solder gap width (s) of up to 100 μm, preferably from 3 nm to 100 μm, particularly preferably from 80 μm or up to 70 μm, particularly preferably from 3 nm to 70 μm, measured from the lowest point of the recess of the microstructure.

13. The substrate (1) according to at least one of the preceding claims, wherein the substrate is a feedthrough element or a component of such a feedthrough element, wherein, In the at least one through hole (4), a conductor (5) is arranged as a functional element in an electrically insulating fixing material (10); Preferably, the diameter of the grounding pin (6) is 1 mm ± 0.02 mm, and at the transition to the surface of the substrate (1), the radius of the meniscus of the metal solder is at most 0.40 mm, preferably at most 0.36 mm, particularly preferably at most 0.30 mm, and most particularly preferably at most 0.22 mm. Preferably, the volume of the metal brazing filler metal is less than 0.16 mm. 3 Preferably less than 0.13 mm 3 Especially preferred is a diameter less than 0.10 mm. 3 The most preferred size is less than 0.07 mm. 3 ;as well as Preferably, the diameter of the brazing area is 1 mm to 2.0 mm.

14. A plurality of substrates for manufacturing airbag igniters, seat belt tensioners, or gas generators, comprising a substrate (1) of 5,000 test quantities as claimed in claim 13, wherein the defect rate in the bending test on the grounding pin is less than 1 to 2,000.

15. A plurality of substrates for manufacturing airbag igniters and / or seat belt tensioners and / or gas generators, comprising substrates for 1,000 test quantities according to claim 13, wherein the standard deviation of the average diameter of the brazed regions in the test quantities is in the range of 0% to 6% of the average diameter of the brazed regions in the test quantities.

16. A method for manufacturing a substrate (1) for a feedthrough element, comprising the following steps: - Provide a metal substrate (1) having a predetermined thickness and a predetermined outer contour, the metal substrate having two substantially opposing surfaces (31, 32). - At least one through hole (4, 20) is formed in the substrate (1); - Microstructure at least one region of the surface of the substrate to introduce depressions in the surface of the substrate (1) to create a microstructure (8). - Provide at least one functional element (5, 6); - Provide electrical insulation fixing materials (10); - Provide at least one conductor (5, 6); - The electrical insulating fixing material (10) is arranged in the at least one through hole (4) and the at least one functional element is fixed in the electrical insulating fixing material; - In the region where the microstructure (8) exists, at least one conductor (5, 6) is brazed to the substrate with a metal solder (7), the metal solder (7) melting during the brazing process, wherein the flow of the molten solder (7) is prevented and / or restricted at least through the area covered by the solder forming the brazing region (7) on the surface of the elements of the microstructure (8) and the substrate, such that the at least one conductor (5, 6) is electrically connected to the substrate in the brazing region; The microstructure is introduced into the matrix in such a way that the average roughness Ra is in the range of 0.35 μm to 15 μm and the average surface roughness Rz is in the range of 1 μm to 50 μm. In the recess, there is at least a pure metal surface or a substantially homogeneous and thin oxide layer (400) with a thickness of less than 10 nm, particularly 1 nm to 6 nm. The recesses of the microstructure (8) are formed such that there are webs between the recesses, the webs being covered by an oxide layer different from the oxide layer on the surface of the recess; or the webs are covered by an oxide layer and the recesses have substantially exposed metal surfaces. as well as The brazing filler metal is a hard brazing filler metal; the palladium content in the brazing filler metal is less than 2000 ppm.

17. The method according to at least claim 16, wherein The microstructure (8) is generated by removing material from the surface of the substrate (1), preferably by grinding the substrate, and particularly preferably by pressing it into the substrate.

18. The method according to at least one of claims 16 and 17, wherein Laser structuring is used to generate the microstructure (8), preferably laser ablation and / or laser desorption, wherein the surface material of the substrate (1), particularly oxide layers and / or organic impurities, is removed under laser radiation, exposing the substantially bare metal surface of the substrate (1) that reflects the incident laser radiation; preferably, the exposed bare metal surface limits the depth of the microstructure. Preferably, wherein, Under the action of the laser radiation, the surface material of the substrate (1) is reshaped in the following way: particularly by local heating, particularly by local melting of the material of the substrate (1) and / or by the pressure effect caused by the laser, wherein at least near the substrate (1), the laser radiation locally heats the gas atmosphere, particularly by locally igniting the plasma, thereby forming a pressure wave that deforms the surface of the substrate.

19. The method according to at least one of claims 16 to 18, wherein The microstructure (8) is given in plan view as a grid and / or rectangular grid and / or mesh structure and / or scale structure in the form of dots.

20. The method according to at least one of claims 16 to 19, wherein After the microstructure is introduced, the matrix (1) in the depression is free of organic materials and / or carbon.

21. The method according to at least one of claims 16 to 20, wherein at least in the region where the microstructure exists, the substrate (1) comprises or is composed of a chromium-containing metal, particularly chromium-containing steel, including high-grade chromium-containing steel; and, at least in the recesses of the microstructure, the surface is oxidized by comprising CrO X and / or NiO X A homogeneous layer is used to cover it; the homogeneous layer preferably includes CrO. X (OH) 2-X • nH2O and / or NiO X (OH) 2-X • nH2O or CrO X (OH) 2-X • nH2O and / or NiO X (OH) 2-X • Composed of nH2O.

22. The method according to at least one of claims 16 to 21, wherein Hard solder is used as the solder (7); preferably, the solder (7) is substantially free of palladium; prior to brazing, the solder is preferably placed around the conductor (6) in a ring such that, during brazing, the solder flows into the microstructure (8) and forms the brazing region (7), wherein in the area of ​​the microstructure (8) filled with solder, there is a solder gap (70) between the surfaces of the conductor (6) and the substrate (1).

23. The method according to at least one of claims 16 to 22, wherein The depth of the microstructure, measured from the surface of the substrate, is at most 70 μm, preferably from 0.7 μm to 70 μm, more preferably from 0.7 μm to 20 μm, particularly preferably from 1 μm to 10 μm, and most particularly preferably from 2 μm to 10 μm.

24. The method according to at least one of claims 16 to 23, wherein Rz is in the range of 1 μm to 15 μm.

25. Use of the substrate (1) according to at least one of claims 1 to 13 in pyrotechnic triggering devices and / or airbag igniters and / or seat belt tensioners and / or gas generators and / or sensors and / or actuators and / or large feedthroughs and / or transistor outline packages and / or electrical storage devices, particularly batteries and / or rechargeable batteries and / or capacitors.

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