Electrical Device

Abstract

In an embodiment a method includes providing a substrate having at least one conductor track situated thereon, applying at least one accumulation of an electrically conductive material to a surface of the conductor track, providing a carrier having at least one electrical contact, applying an electrically conductive adhesive to the at least one accumulation of the electrically conductive material and/or the at least one electrical contact and arranging the substrate and the carrier such that the accumulation of the electrically conductive material and the at least one electrical contact are situated opposite and at a distance from one another, wherein the electrically conductive adhesive forms a mechanical and electrical connection between the accumulation of the electrically conductive material and the at least one electrical contact, and wherein an interspace between the at least one accumulation of the electrically conductive material and the at least one electrical contact is filled with the electrically conductive adhesive.

Claims

1-21. (canceled)

22. A method for producing an electrical device, the method comprising: providing a substrate having at least one conductor track situated thereon; applying at least one accumulation of an electrically conductive material to a surface of the conductor track; providing a carrier having at least one electrical contact; applying an electrically conductive adhesive to the at least one accumulation of the electrically conductive material and/or the at least one electrical contact; and arranging the substrate and the carrier such that the at least one accumulation of the electrically conductive material and the at least one electrical contact are situated opposite and at a distance from one another, wherein the electrically conductive adhesive forms a mechanical and electrical connection between the at least one accumulation of the electrically conductive material and the at least one electrical contact, and wherein an interspace between the at least one accumulation of the electrically conductive material and the at least one electrical contact is filled with the electrically conductive adhesive.

23. The method as claimed in claim 22, wherein the conductor track comprises aluminum.

24. The method as claimed in claim 22, wherein the at least accumulation of the electrically conductive material comprises at least one of the following materials gold, silver, copper, combinations thereof or a metal having a higher standard potential than a material of the conductor track.

25. The method as claimed in claim 22, wherein the surface of the conductor track has an oxidized layer, and wherein the oxidized layer is removed and/or perforated in a region of the at least one accumulation of the electrically conductive material.

26. The method as claimed in claim 22, wherein the at least one accumulation of the electrically conductive material has a shape of at least one drop and/or tail and/or wedge.

27. The method as claimed in claim 26, wherein the shape of the at least one drop and/or tail and/or wedge is realized by the electrically conductive material being applied and/or melted onto the surface of the conductor track, and wherein a material excess that protrudes from the at least one drop and/or tail and/or wedge is torn off and/or sheared off at a location directly above the at least one drop and/or tail and/or wedge.

28. The method as claimed in claim 26, wherein at least two out of the at least one drop, tail and wedge are connected to one another via a bonding wire.

29. The method as claimed in claim 22, wherein applying the at least one accumulation of the electrically conductive material to the surface of the conductor track is realized by at least one of the following methods: ultrasonic bonding, ultrasonic welding, spot welding, or wire bonding.

30. The method as claimed in claim 22, wherein the substrate comprises an optoelectronic component.

31. The method as claimed in claim 30, wherein the conductor track comprises at least one conductor loop having at least two ends, and wherein the conductor track is configured for checking a functionality of the optoelectronic component.

32. The method as claimed in claim 22, wherein the carrier has a cavity, in which the substrate having the conductor track situated thereon, is arranged.

33. An electrical device comprising: a substrate having at least one conductor track situated thereon; a first accumulation of an electrically conductive material on a surface of the conductor track; a carrier having a first electrical contact; and an electrically conductive adhesive, wherein the substrate and the carrier are arranged such that the first accumulation of the electrically conductive material and the first electrical contact are situated opposite and at a distance from one another, and wherein the electrically conductive adhesive arranged between the first accumulation of the electrically conductive material and the first electrical contact and the electrically conductive adhesive electrically and mechanically connects the substrate and the carrier to one another, and wherein an interspace between the first accumulation of the electrically conductive material and the first electrical contact is filled with the electrically conductive adhesive.

34. The electrical device as claimed in claim 33, wherein the conductor track comprises aluminum.

35. The electrical device as claimed in claim 33, wherein the first accumulation of the electrically conductive material comprises at least one of gold, silver, copper, combinations thereof or a metal having a higher standard potential than a material of the conductor track.

36. The electrical device as claimed in claim 33, wherein the surface of the conductor track comprises an oxidized layer, and wherein the oxidized layer is removed and/or perforated in a region of the first accumulation of the electrically conductive material.

37. The electrical device as claimed in claim 33, wherein the first accumulation of the electrically conductive material is formed in a shape of a first drop or a tail and has a torn-off area and/or a cut area at a location directly above the first drop or tail.

38. The electrical device as claimed in claim 37, wherein the first accumulation of the electrically conductive material comprises the shape of the first drop or the tail, from which a bonding wire runs to a second drop or a wedge, and wherein the second drop or wedge is arranged at a distance from the first drop or the tail likewise on the conductor track.

39. The electrical device as claimed in claim 33, wherein the substrate comprises an optoelectronic component.

40. The electrical device as claimed in claim 33, further comprising: a second accumulation of an electrically conductive material on the surface of the conductor track, wherein the second accumulation of an electrically conductive material is situated opposite a second electrical contact of the carrier, and wherein the electrically conductive adhesive is at least also arranged between the second accumulation of the electrically conductive material and the second electrical contact and electrically and mechanically connects them to one another.

41. The electrical device as claimed in claim 40, wherein the conductor track comprises at least one conductor loop having at least two ends, and wherein the first and second accumulations of the electrically conductive material are each arranged at one end of the conductor track.

42. A method for testing the electrical device as claimed in claim 41, the method comprising: applying a measuring sensor to each of the first and second electrical contacts; and measuring, via the conductor, a voltage drop, a resistance, or an electrical conductance.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Exemplary embodiments of the invention are explained in greater detail below with reference to the accompanying drawings, in which, in each case schematically,

[0039] FIG. 1 shows a plan view of one exemplary embodiment of a substrate of an electrical device;

[0040] FIGS. 2A and 2B show sectional views through the substrate of two exemplary embodiments of an electrical device;

[0041] FIG. 3A shows a plan view of one exemplary embodiment of an electrical device;

[0042] FIG. 3B shows a sectional view of one exemplary embodiment of an electrical device;

[0043] FIG. 4 shows yet another plan view of one exemplary embodiment of a substrate of an electrical device;

[0044] FIGS. 5A and 5B show further sectional views through the substrate of two exemplary embodiments of an electrical device;

[0045] FIG. 6 shows a method for producing an electrical device according to embodiments of the invention; and

[0046] FIG. 7 shows a method for testing an electrical device according to embodiments of the invention with regard to its functionality.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0047] FIG. 1 shows a plan view of one exemplary embodiment of a substrate (2) of an electrical device (1) according to the invention. A conductor track (3) in the shape of a conductor loop is arranged on the substrate (2). In this case, the conductor loop comprises a first end and a second end and, as illustrated in FIG. 1, is arranged for example in the shape of an open rectangle on a for example square substrate (2). However, it is likewise possible to arrange the conductor track in the shape of an open circle, in the shape of an open ellipse or in a comparable shape on a surface of the substrate (2), which can for example also be formed in the shape of a circle, an ellipse or some other comparable shape.

[0048] The conductor track (3) is applied in the shape of a thin layer, in particular thin in relation to the main extension direction of the conductor track (3), on a surface of the substrate (2). Furthermore, the conductor track (3) covers a surface of the substrate (2) only partly, in some embodiments in particular to the extent of less than 50%, to the extent of less than 25%, to the extent of less than 10%, or to the extent of less than 5%.

[0049] On the top side of the conductor track (3), which is the opposite side with respect to the substrate, a first accumulation of an electrically conductive material (4a) is arranged on the first end of said conductor track and a second accumulation of an electrically conductive material (4b) is arranged on the second end of said conductor track.

[0050] The first and second accumulations of an electrically conductive material (4a, 4b) respectively cover the first and second ends of the conductor track (3) only in parts. In this regard, it may be expedient, for example, for the first and second accumulations of an electrically conductive material (4a, 4b), as seen in plan view, to have a smaller area, in particular much smaller area, than the area of the conductor track (3) as seen in plan view. In some embodiments, however, it is also possible for the first and second accumulations of an electrically conductive material (4a, 4b) to respectively cover the first and second ends of the conductor track (3) completely in each case.

[0051] FIGS. 2A and 2B each show a sectional view along the dashed line A-A in FIG. 1. The two figures accordingly show a sectional or side view through the substrate (2), the conductor track (3), and also the second accumulation of an electrically conductive material (4b).

[0052] An oxidized layer (9) is arranged on the opposite surface (5) of the conductor track (3) with respect to the substrate (2). Besides the surface (5), the oxidized layer (9) is also arranged on the side walls of the conductor tracks (3). In this case, the oxidized layer (9) is formed in particular so as to be thin in relation to the thickness of the conductor track (3) and usually has a thickness of a few nanometers.

[0053] Furthermore, the oxidized layer (9) is interrupted in the region of the at least second accumulation of an electrically conductive material (4b) or is perforated by at least the second accumulation of an electrically conductive material (4b). Accordingly, a direct contact between at least the second accumulation of an electrically conductive material (4b) and the conductor track (3) is realized at least in the region of the second accumulation of an electrically conductive material (4b).

[0054] The first and second accumulations of an electrically conductive material (4a, 4b) can be applied to the surface of the conductor track for example by means of a method similar to a wire bonding process, in particular a ball-wedge bonding process or a wedge-wedge bonding process. However, this is not intended to be limiting thereto, rather the first and second accumulations of an electrically conductive material (4a, 4b) can also be applied to the conductor track by means of a comparable process.

[0055] As shown in FIG. 2A, at least the second accumulation of an electrically conductive material (4b) is formed in the shape of a drop. However, it is likewise also possible for at least the second accumulation of an electrically conductive material (4b) to be formed in the shape of a tail (ta), as shown in FIG. 2B. In this case, the shape of a drop (t1) is formed to the greatest possible extent in a manner corresponding to the shape of the ball of a ball-wedge bonding process, i.e. a ball having a material stump protruding therefrom. The shape of a tail (ta) as illustrated in FIG. 2B is formed to the greatest possible extent in a manner corresponding to a tail of a wedge-wedge bonding process, i.e. a wire which is pressed flat onto the conductor track in one region and, in a region adjacent thereto, has a material stump protruding therefrom. However, this is not intended to be limiting to the shapes known from the wire bonding process, rather it is likewise conceivable for the accumulation of an electrically conductive material also to have other comparable shapes.

[0056] FIG. 3A shows one exemplary embodiment according to the invention of an electrical device (1). The substrate (2) having the conductor track (3) situated thereon is arranged on a carrier (6) having the electrical contacts (7a, 7b) situated thereon. The substrate (2) having the conductor track (3) situated thereon and the accumulation of an electrically conductive material (4a, 4b) in turn situated thereon and the carrier (6) are arranged in such a way that the first and second accumulations of an electrically conductive material (4a, 4b) and a respective electrical contact (7a, 7b) are situated opposite and at a distance from one another.

[0057] Furthermore, an electrically conductive adhesive (8) is arranged between at least the first accumulation of an electrically conductive material (4a) and at least one of the electrical contacts (7a) in accordance with the sectional view along the line B-B in FIG. 3B. A mechanical connection between the substrate (2) and the carrier (6) and also an electrical connection between at least the first accumulation of an electrically conductive material (4a, 4b) and at least one of the electrical contacts (7a) are provided by means of said electrically conductive adhesive (8).

[0058] As shown in FIG. 3A, the carrier (6) has a window (ii), on which the substrate (2) having the conductor track (3) situated thereon is arranged. Furthermore, the carrier can have a cavity, not illustrated, in which the substrate (2) having the conductor track (3) situated thereon can be arranged. On account of the arrangement in the cavity, it may be possible, for example, that a connection by means of a mechanical pressure, such as US welding, for example, is made more difficult owing to the space available. Accordingly, the present invention proposes a method in which an at least first and an at least second accumulation of an electrically conductive material (4a, 4b) are applied to the conductor track (3) for example by means of a mechanical method, such as US welding, for example, and the resultant intermediate product is adhesively bonded onto electrical contacts (7a, 7b) into a cavity of a carrier (6) by means of an electrically conductive adhesive (8). As a result, it is possible to decouple a mechanical process and an adhesive bonding process.

[0059] In further embodiments, not illustrated, it is also possible for the electrically conductive adhesive to be formed laminarly between the conductor track (3) and the electrical contacts (7a, 7b) and/or between the conductor track (3) and the carrier (6) and/or between the substrate (2) and the carrier (6) and/or between the substrate (2) and the electrical contacts (7a, 7b).

[0060] The electrical contacts (7a, 7b) can be formed for example from a material such as gold, silver, or a comparable conductive material, and can be configured to enable the conductor track (3) to be electrically contacted via the electrically conductive adhesive and the first and second accumulations of an electrically conductive material (4a, 4b).

[0061] In accordance with FIG. 3B, the electrically conductive adhesive (8) comprises electrically conductive particles (12). As a result, it is possible to provide an electrical connection between the first and second accumulations of an electrically conductive material (4a, 4b) and the electrical contacts (7a, 7b). By increasing the concentration of the electrically conductive particles (12) in the electrically conductive adhesive (8), it is possible to provide an improved electrical connection between the first and second accumulations of an electrically conductive material (4a, 4b) and the electrical contacts (7a, 7b).

[0062] FIG. 4 shows a further exemplary embodiment of a substrate (2) of an electrical device (i) according to the invention. In contrast to the exemplary embodiment shown in FIG. 1, the first and second accumulations of an electrically conductive material (4a, 4b) have two regions which are mechanically connected to the leadframe and which are connected to one another via a wire, for example a bonding wire.

[0063] This is shown in more specific detail once again in a side/sectional view in FIGS. 5A and 5B. FIIG. 5A shows for example a first or second accumulation of an electrically conductive material (4a, 4b) comprising a first drop (t1) and a wedge (w), which are connected to one another via a bonding wire (b). In contrast thereto, FIG. 5B shows a first or second accumulation of an electrically conductive material (4a, 4b) comprising a tail (ta) and a wedge (w), which are likewise connected to one another via a bonding wire (b).

[0064] The shapes of a first and/or second accumulation of an electrically conductive material (4a, 4b) as shown in FIGS. 5A and 5B can thus be produced for example by means of a commercial wire bonding process, in particular a ball-wedge bonding process or a wedge-wedge bonding process. However, this is not intended to be limiting thereto, rather the shapes can also be applied to the conductor track by means of a comparable process.

[0065] FIG. 6 shows steps S1-S6 of a method according to the invention for producing an electrical device. In a step S1, a substrate having at least one conductor track situated thereon is provided. In this case, the conductor track can be formed in the shape of a conductor loop and can be embodied for example in the shape of an open rectangle, in the shape of an open circle, in the shape of an open ellipse, or a comparable shape. The material of the conductor track can be for example cost-effective materials, such as aluminum, copper, a metal alloy comprising aluminum or copper, or a comparable material.

[0066] In a step S2, at least one accumulation of an electrically conductive material is subsequently applied to a surface of the conductor track, in particular to an opposite surface of the conductor track with respect to the substrate. In this case, applying the at least one accumulation of an electrically conductive material optionally comprises the following steps: providing an electrically conductive material for example in the form of a bonding wire, in particular continuous bonding wire; arranging the electrically conductive material, in particular a part of the electrically conductive material, on the surface of the conductor track; melting the electrically conductive material, in particular a part of the electrically conductive material; connecting the electrically conductive material to the conductor track, wherein the connecting is realized by at least one of the following methods: ultrasonic bonding, ultrasonic welding, spot welding and wire bonding.

[0067] In this case, the optional step of connecting is realized in particular by means of a mechanical method in order to perforate an oxide layer that possibly envelops the conductor track, and to provide a direct contact between the conductor track and the at least one accumulation of an electrically conductive material.

[0068] The at least one accumulation of the electrically conductive material can comprise at least one of the following materials: gold, silver, copper, a combination of these materials, and a metal having a higher standard potential than a material of the conductor track.

[0069] In a step S3, a carrier having at least one electrical contact situated thereon is provided. In this case, the carrier can have for example a cavity and/or a window or a perforation and the at least one electrical contact can comprise a material such as gold, silver, or a comparable material. In particular, it may be possible for the material of the at least one electrical contact situated on the carrier to differ from the material of the conductor track.

[0070] In a step S4, an electrically conductive adhesive is applied to at least one out of the accumulation of the electrically conductive material and the at least one electrical contact. In further embodiments, however, the adhesive is for example also applied to the conductor track and/or the substrate and/or to the carrier.

[0071] In a step S5, the substrate and the carrier are arranged with respect to one another in such a way that the at least one accumulation of the electrically conductive material and the at least one electrical contact are situated opposite and at a distance from one another. In this case, the electrically conductive adhesive produces in particular a mechanical and electrical connection between the accumulation of the electrically conductive material and the at least one electrical contact.

[0072] FIG. 7 shows steps S6-S7 of a method according to the invention for testing one of the electrical devices described above. In this case, in a step S6, a measuring sensor is applied to each of the first and second electrical contacts of the carrier. A step S7 subsequently involves measuring an electrical variable, in particular the voltage drop, the resistance, or the electrical conductance, via the conductor track. On the basis of such a measured value, it may be possible, in a further step, to deduce a possible malfunction of the electrical device.

[0073] Although the invention has been illustrated and described in detail by means of the preferred embodiment examples, the present invention is not restricted by the disclosed examples and other variations may be derived by the skilled person without exceeding the scope of protection of the invention.