Method for producing an electronic component and electronic component

Abstract

The invention relates to the field of electrical engineering and to a method for producing an electronic component having at least one electronic component (12) which is electrically connected by wire bonding to a section (14.1) of a strip (4) made of a substrate material, the strip (4) being rolled by rolling the substrate material, the invention relates to a method for producing an electronic component (12), comprising the following steps: rolling a strip made of a substrate material, removing a surface (8) formed by rolling in order to form exposed contact points (6) on the strip made of the substrate material, winding the rolled strip (4) in order to form a coil (10), unwinding the rolled strip (4) from the coil (10) and separating a section (14.1) from the strip (4), and bonding a wire (16) to the contact points (6) in an electrically conductive manner in order to electrically connect the electronic component (12). The invention also relates to an electronic component manufactured according to the method, and to a unit (18) prepared for shipping, comprising a coil (10) having exposed contact points (6) on a strip (4) for wiring, at which contact points a surface (8) formed by rolling is removed and a base material of the coil (10) is exposed.

Description

[0001] This invention relates to the field of electrical engineering, and specifically to an electronic component having at least one electronic element electrically connected to a segment of a strip made of a carrier material via wire bonding; a method for manufacturing such an electronic component; and a coil formed and configured by a strip made of a carrier material for a wire bonding process, the wire bonding process being part of the manufacturing method.

[0002] The reliability and service life of contact systems in switchgear, electromechanical components, and electronic components usually depend not only on the contact materials used, but also on the selection of appropriate carrier materials.

[0003] Copper substrates are the most important carrier materials. Depending on the application, nickel substrates or multilayer composite materials, such as thermal bimetallic materials, may also be used.

[0004] The requirements for substrate materials vary depending on the application. For example, copper materials need to have high electrical and thermal conductivity, good strength even at high temperatures, and sufficiently high corrosion resistance. If the substrate material is used as a contact spring, the material must also have good elasticity. In addition, depending on the manufacturing process, certain technical characteristics must be met, such as good thermoformability and cold formability, machinability, stamping ability, weldability, solderability, and electroplating performance.

[0005] Copper and copper alloy materials intended for use in electrical engineering and electronics are typically specified in standards. The substrate material of this invention conforms to DIN standards; specifically, it conforms to DIN EN 1758.

[0006] In electronic and electrical engineering, the carrier material is not usually used only for conducting electrical power, especially power supply current. Sometimes, electronic components such as transistors, light-emitting diodes, or photodiodes are also directly connected to the carrier material.

[0007] Wire bonding is an electrical connection technique that uses high-frequency mechanical excitation to bond fine wires (such as Au and Al) with diameters ranging from 50 µm to 300 µm to the surface of a planar metal or semiconductor device. This bonding process is commonly used in semiconductor devices to achieve electrical connections between semiconductors and system carriers (typically made of copper alloy strips).

[0008] Wire bonding processes require flawless surfaces. In the rolling production of carrier materials supplied in the form of wound rings / coils, their surfaces come into contact with metal tools (rollers, straightening rolls) and deflection rolls in multiple process steps. During this process, defects and particles from the tools or rolls can transfer to the surface of the carrier material. Furthermore, relative movement between coils, such as during transport, can also cause scratches and other defects on the surface, rendering it unsuitable for wire bonding. Therefore, to obtain the flawless surfaces required for wire bonding, numerous measures must be taken during the production and testing of the carrier material.

[0009] The present invention aims to provide a solution to the above-mentioned problems.

[0010] According to a first aspect of the invention, a method for manufacturing an electronic component is provided, the electronic component comprising at least one electronic component electrically connected to a segment of a strip made of a carrier material via wire bonding. In this method, the strip is rolled in a manner known per se by rolling a base material. Surfaces formed by rolling are removed to form exposed contact points on the strip formed of the base material. The rolled strip is then wound into a coil. The contact points are typically formed before the coil is wound, preferably by passing the coil through a machining station at a feed rate specified by the rolling process. The contact points can be formed by chip removal machining, preferably along the rolling direction.

[0011] Coils produced in this manner are typically ready for assembly as part of the overall production process, for which the coils are placed on transport pallets and secured or fastened with transport fasteners. The design concept of this invention is to produce the coils during metalworking operations, while additional processing steps, particularly wire bonding for electrical connections to electronic components, are carried out during the electrical engineering operations of transporting the coils.

[0012] At this point, the rolled strip is unwound from the coil, and the section is separated from the strip. For electrical connection to electronic components, wiring is bonded at the contact points using electrical conductivity. This wiring can be simultaneously bonded to the electronic components.

[0013] The coil is formed from a strip made of a carrier material. This strip is formed by rolling a base material, and the strip has a surface formed by the rolling process. According to the invention, at least one contact point exposed on the strip is formed on the strip-shaped carrier material, and the surface formed by the rolling process at this contact point is removed. Therefore, the contact point is lower in height than the surface formed by the rolling process. The contact point is spaced a distance from the surface formed by the rolling process along the direction of the center of the carrier material. It exposes and is formed from the base material of the coil. The contact point is preferably formed only partially on the strip, meaning that in other cases the contact point is completely or partially surrounded by the surface formed by the rolling process. The contact point can be formed as a continuous elongated strip along the rolling direction. In this case, one side (preferably both sides) of the contact point is surrounded by the surface formed by the rolling process. The contact point can also be formed at a specific location so that it is completely surrounded by the surface formed by the rolling process.

[0014] The contact points are used to remove impurities and modify the substrate material near the surface produced by rolling. The substrate material at the contact points is free of defects, dents, scars, and destructive foreign particles. This allows for consideration of the morphology and material requirements of wire bonding processes. Even if the wire bonding process requires pre-plating at the contact points, the conditions for the bonding process are significantly improved compared to a rolled surface. Because the contact points are deeper than the surface formed by rolling, they are not subject to relative movement between adjacent windings during transport. Thus, even if the carrier material with defined contact points is in the form of a coil with a large number of windings, it can be supplied to carrier material processors in electronic or electrical engineering.

[0015] One of the contact points is typically located on one surface of the strip, or, if necessary, on two opposing surfaces of the strip, surfaces formed by rolling. The wording herein is intended to indicate that the strip has two primary side surfaces whose lengths are significantly greater than the end surfaces connecting these primary side surfaces. These end surfaces can also be machined by rolling. However, they are not necessarily formed by rolling. At least one contact point is located on a primary side surface.

[0016] It should be understood that in the mass production of coils and their use in this manufacturing process, the contact points are typically arranged at pre-defined fixed positions on the strip at periodic intervals. This allows the corresponding electrical conductor for electronic or electrical engineering applications to be separated from the coil at various lengths of the strip carrier material. The contact points are usually located between various cut edges that isolate a section of the strip from the coil.

[0017] As described above, preferably, the base material is a copper alloy. Preferably, the strip conforms to DIN EN ISO 1758.

[0018] As described above, the contact point is below the surface formed by rolling. The contact point is typically between 30 µm and 150 µm from the surface formed by rolling.

[0019] At the point of contact, preferably, the material forming the surface created by rolling is removed by cutting.

[0020] This can be achieved by peeling or scraping the surface of the finished rolled strip material. During peeling or scraping, the tool remains stationary while the workpiece moves relative to the tool. Unlike milling, this material handling method does not leave any visible structures on the surface perpendicular to the rolling direction. These structures perpendicular to the rolling direction can be detrimental to bonding processes, as wiring also needs to be bonded to surfaces perpendicular to the rolling direction. Therefore, the invention also relates to a coil formed from a strip made of a carrier material used in components in electronic or electrical engineering, wherein the surface of the strip is formed by rolling a substrate material. The strip has at least one exposed contact point for wiring, to which the wiring is electrically connected by wiring bonding. At this contact point, the surface formed by rolling is removed by scraping. The substrate material of the coil is exposed at the contact point.

[0021] The width of each contact point in the contact points is typically between 2 mm and 10 mm.

[0022] To manufacture the coil according to the invention, the following process is used: First, a strip is formed by rolling a base material. Then, material from the carrier material is partially removed from the surface of the rolled strip to form exposed contact points on the strip, preferably using the method described above. Finally, the strip material is wound up to form a coil.

[0023] The strip material prepared according to this method can be fed by the carrier material manufacturer to an electroplating process as needed, or it can be fed to a stamping press that unwinds the strip from the coil and stamps it out at the point of use, for example, for a semiconductor system carrier, such as as a fixed-length cut or a coiled stamped strip. These and subsequent processes are comparable to those used for materials for which no surface removal is performed in the wire bonding region, and are all state-of-the-art technologies.

[0024] Further details and advantages of the present invention will become apparent from the following description of embodiments of the invention taken in conjunction with the accompanying drawings: Figure 1 It is a perspective cross-sectional view of a strip of material; Figure 2This is a perspective view of the coil, with the end of the strip forming the coil; Figure 3 It is used according to Figure 1 Side view of a strip-bonded circuit breaker; Figure 4 yes Figure 4 Top view; Figure 5 This is a perspective view of the unit ready for shipment.

[0025] Figure 1 An example of the carrier material, CuSn6 R500, is shown. This example shows a cross-sectional view of strip 4 passing through longitudinal member 2, which is transverse to the rolling direction (indicated by the arrow with reference numeral W). The thickness S of strip 4 is approximately 0.8–0.02 mm, and the width B is 30–0.02 mm.

[0026] Reference mark 6 indicates two contact points near the edge of the strip 4, which are formed by machining the surface 8 formed by rolling. In the example, the distance A between the contact point 6 and each edge of the longitudinal member 2 is 10 mm. Both the length L and the distance A are measured transversely to the rolling direction. This machining forms the contact point 6 in the height direction in the base material BA of the strip located below the surface 8, with the strip being formed from melt and rolled to the desired thickness S using these contact points. Figure 1 The reference mark M in the figure indicates the area near the surface of the rolled strip 4, which may be unnecessarily altered by the rolling process, thus enabling electrical connection via wire bonding.

[0027] Contact point 6 is defined at a 45° angle at the transition with surface 8, and its width b is 5 mm. As shown by the reduced thickness dimension R, the thickness of strip 4 at contact point 6 is only 0.77 mm ± 0.012 mm. The reduced thickness of strip 4 is achieved by processing surface 8 of strip 4. The reduced thickness R is selected such that the modified surface area M is reliably removed by material removal, exposing strip 4 and its base material B within contact point 6, thereby maintaining the predetermined material properties of the strip at that location.

[0028] In the illustrated embodiment, contact point 6 is formed by a peeling process. This results in a surface roughness of Ra = 0.018 µm and Rmax = 0.705 µm at contact point 6 along the rolling direction. The roughness in the transverse direction (i.e., perpendicular to the longitudinal direction) is Ra = 0.173 µm and Rmax = 1.228 µm.

[0029] Figure 2 An example of a coil 10 formed from strip 2 is shown, which strip 2 is used for... Figure 1 The modifications. For example... Figure 2 The representation of the free end of strip 2 is shown, and... Figure 1 Compared to the embodiment shown, this strip 4 has only a single contact point 6. For details regarding this contact point 6, please refer to the previous section... Figure 1 The description.

[0030] Figure 3 and Figure 4 The semiconductor switch 12 is shown and according to Figure 1 The strip 4 is attached and connected. The strip is divided into several segments 14 by stamping, and segments 14.1 of the segments 14 form busbars for the power supply current switched by the semiconductor switch 12. Each of these segments 14.1 is formed by stamping the edge of the strip 4. The semiconductor switch 12 is electrically connected to one of the segments 14.1 through its wiring bridge / pin 16.

[0031] Section 14.2 is stamped from the center of strip 4. In the illustrated embodiment, it carries the power switch 12 and serves as a busbar for the polarity switched by the semiconductor switch 12.

[0032] The extent of extension of section 14.2 in the rolling direction is equal to the sum of the extents of extension of section 14.1 on one side of section 14.2 in the rolling direction.

[0033] Figure 5 An example of a shipping unit 18 is shown, which includes a coil 10, a pallet 20, and a retaining strap 22.

[0034] In an operating facility equipped with a strip 4 having contact points 6, after the contact points 6 are formed, the strip 4 is wound into a coil 10, placed on a pallet 20, and secured with a retaining strap 22 for transport. Once prepared in this manner, the unit 18 is ready to be shipped to the operating facility where bonding is performed.

[0035] List of reference numerals 2 length pieces 4 strip 6 contact points 8 surfaces 10 coils 12 Semiconductor Switches Section 14.1 14.2 Middle Section 16 wiring bridges / pins 18 shipping units 20 pallets 22 fixing straps Distance A B strip width b. Width of contact point R decreases in thickness S-thickness.

Claims

1. A method for manufacturing an electronic component, the electronic component having at least one electronic element (12), the at least one electronic element (12) being electrically connected to a segment (14.1) of a strip (4) by wire bonding, the strip (4) being made of a carrier material, wherein, - The strip (4) is rolled by rolling the base material; - Remove the surface (8) formed by rolling to form exposed contact points (6) on the strip (4) formed of the base material. - The rolled strip (4) is wound into a coil (10). - The rolled strip (4) is unwound from the coil (10), and the section (14.1) is separated from the strip (4); as well as - The wiring (16) is electrically bonded to the contact point (6) to achieve electrical connection of the electronic component (12).

2. The method of claim 1, wherein, The contact point (6) is formed continuously along the rolling direction (W) by removing surface material from the carrier material.

3. The method of claim 1, wherein, The carrier segment (14.2) is separated from the strip (4), and the electronic component (12) is mounted on the carrier segment (14.2).

4. The method of claim 1, wherein, The surface (8) formed by rolling is removed, such that the contact point (6) is defined on at least two sides by the surface (8) formed by rolling.

5. The method of claim 1, wherein, The surface formed by rolling is removed by scraping (8).

6. A shipping unit (18) for components in electronic or electrical engineering, the shipping unit (18) comprising: A coil (10) is formed by a strip (4) made of a carrier material, wherein the strip (4) has a surface (8) formed by rolling a base material; and a transport pallet on which the coil (10) rests and is securely connected for transport, wherein wiring (16) is electrically connected to an exposed contact point (6) on the strip (4), wherein at the contact point (6), the surface (8) formed by rolling is removed and the base material of the coil (10) is exposed.

7. The shipping unit (18) according to claim 6, wherein, The substrate material is a copper alloy.

8. The shipping unit (18) according to claim 6, wherein, The strip (4) conforms to DIN ISO 1758.

9. The shipping unit (18) according to claim 6, wherein, At the contact point (6), the surface (8) formed by rolling is removed by a distance (A) between 30 µm and 150 µm from the surface (8) formed by rolling.

10. The shipping unit (18) according to claim 6, wherein, At the contact point (6), the material used to form the surface (8) formed by rolling is removed by cutting.

11. The shipping unit (18) according to claim 10, wherein, The material used to form the surface (8) is removed by scraping.

12. The shipping unit (18) according to claim 6, wherein, The width (b) of the contact point (6) is between 2 mm and 10 mm.

13. The shipping unit (18) according to claim 6, wherein, The contact point (6) is defined on at least one side by the surface (8) formed by rolling.

14. An electronic component having at least one electronic element (12) electrically connected by wire bonding to a segment (14.1) of a strip (4) made of a carrier material, wherein, The segment (14.1) has a surface (8) formed by rolling a base material (8) and an exposed contact point (6) at which the surface (8) formed by rolling has been removed. The contact point (6) is formed by the base material of the coil and is used to electrically connect the electronic component (12) to the wiring of the segment (14.1) to the contact point (6).

15. The electronic component according to claim 14, further comprising a carrier segment (14.2) formed of the strip (4), wherein the electronic element (12) is mounted on the carrier segment (14.2).

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