Resistance element for surface mounting on a conductor plate and conductor plate with at least one resistance element mounted on it

Description

[0001] The present invention relates to a resistor component for surface mounting on a printed circuit board. Furthermore, the present invention relates to a printed circuit board with at least one resistor component arranged thereon. Documents KR20180072489A, RU2158419C1, JP2006080322A, and JP3665385B2 represent the closest prior art.

[0002] In power semiconductor modules, electronic components such as resistors are mounted on circuit boards using surface mounting. For this purpose, resistors that do not have wire leads are often soldered directly onto the circuit board using solderable pads.

[0003] Sinterable resistor components, such as temperature sensors or resistors for power electronics, can also be surface-mounted on the circuit board. For this purpose, cylindrical components with a usually metallized and flat underside intended for sintering are electrically connected to a surface of the circuit board using a sintering layer, for example a silver-containing sintering paste. Contact can be made using the metallized underside and at least one contact pad arranged on a top side of the resistor component opposite the underside. To achieve higher electrical loads, contact can also be made using two contact pads arranged on the top side of the resistor component, which are electrically insulated from the metallized underside.The top-side contacting of the contact pads is typically achieved by wire bonding, soldering, or sintering. For example, DE102010050315B4 describes an electrical component with contact pads for contacting on the top side of the electrical component and an opposite electrically insulated metallization for sintering on potential-carrying surfaces, such as a conductor track running on the circuit board.

[0004] However, the contact surfaces of state-of-the-art surface-mount resistor components are often spatially limited due to the small dimensions of the resistor component. Therefore, reliable electrical contact between the contact pads is difficult to achieve.

[0005] The object of the present invention is therefore to provide an improved resistor component for surface mounting on a printed circuit board.

[0006] This object is achieved according to the invention by a resistance component according to the subject matter of claim 1.

[0007] The resistor component according to the invention for surface mounting on a printed circuit board has: a ceramic substrate having a first side and an opposite second side, wherein a sinterable metallization is arranged at least in regions on the second side; a resistance element having a metal layer arranged at least in regions on the first side of the ceramic substrate with a first terminal and a second terminal; an insulation layer arranged at least in regions on the resistance element and the ceramic substrate, wherein a first region on the first terminal and a second region on the second terminal remain uncovered by the insulation layer;and a first contact pad that electrically contacts the first terminal via the first region, and a second contact pad that electrically contacts the second terminal via the second region, wherein the first contact pad covers a first surface region of the insulation layer at least in regions and the second contact pad covers a second surface region of the insulation layer at least in regions, and the first and second contact pads are arranged spatially separated from one another on the insulation layer. ;

[0008] The ceramic substrate can, for example, comprise one or more materials from the group consisting of Al2O3, AlSiC, AIN, B4C, BN, PBN, MgO, SiC, SiSiC, SSiC, Si3N4, YSZ, or PZT, and can be provided in plate form for constructing a plurality of resistor components on the ceramic substrate. After constructing the resistor components, the ceramic substrate can be structured to obtain the individual resistor components. The electrically insulating properties of the ceramic substrate enable the contact pads to be arranged on the first side of the ceramic substrate, which are held electrically insulated from the metallized second side of the ceramic substrate.

[0009] The sinterable metallization can, for example, comprise one or more materials from the group: NiAu, NiPdAu, AgPd, AuPd, Au, Ag or Cu and can be arranged in regions or over the entire surface on the second side of the ceramic substrate.

[0010] The resistance element according to the invention comprises a metal layer with a first terminal and a second terminal, or is manufactured with the metal layer. The metal layer is arranged at least partially on the first side of the ceramic substrate. The metal layer can be configured as a conductor track that runs flat, meandering, or helically between its ends and has a defined resistance value and temperature coefficient at a specific temperature.

[0011] An insulation layer can be understood as an electrically insulating layer, for example a glass ceramic, arranged on regions of the metal layer and on regions of the first side of the ceramic substrate that are not covered by the metal layer. A first region on the first terminal and a second region on the second terminal remain uncovered by the insulation layer. For example, the insulation layer can completely cover a first side of the ceramic substrate except for the first region above the first terminal and the second region above the second terminal.The uncovered first region and second region can be configured as openings that enable electrical contacting of the respective terminal, for example, via a section of an electrical conductor that extends through the openings in the insulating layer and enables contacting of the terminals on the side of the insulating layer facing away from the first surface of the ceramic substrate. The electrical contacting of the terminals can also be established directly through the material of the contact pads. The term "opening" can also be understood as a recess or a region uncovered by the insulating layer on the first side of the ceramic substrate lying beneath the insulating layer.

[0012] The contact pads each cover a surface area of ​​the insulation layer. A "contact pad" can be understood as a thin layer of electrically conductive material that is arranged essentially flat on the surface of the insulation layer and is indirectly or directly connected to a terminal of the metal layer.

[0013] "Spatially separated on the insulation layer" can be understood as an arrangement of the first contact pad and the second contact pad on the insulation layer so that the two contact pads do not touch each other.

[0014] The invention makes it possible for the first time to provide a resistance component for surface mounting on a printed circuit board with contact pads which, due to their arrangement, provide a sufficiently large area for contacting with heavy wire, for example by means of ball bonding or wedge bonding, at least in some areas on the insulation layer.

[0015] In one example, the first and second surface areas together cover at least 70% of a total surface area of ​​the insulation layer on the first side of the ceramic substrate.

[0016] Advantageously, in the resistor component according to the invention, almost the entire surface area of ​​the insulation layer, which in turn can extend over the second side of the ceramic substrate, is available. Thus, the surface area of ​​the contact pads can be significantly increased compared to resistor components known from the prior art.

[0017] In one example, the first and second surface regions cover at least partially a surface of the insulation layer that runs parallel to the first side of the ceramic substrate with the resistance element arranged thereon.

[0018] Advantageously, the contact pads are arranged parallel to the first side of the substrate and the circuit board. This arrangement enables good contactability using known bonding methods.

[0019] In a further example, the first and second surface regions cover at least partially a surface of the insulation layer that runs perpendicular to the first side of the ceramic substrate with the resistance element arranged thereon.

[0020] The arrangement perpendicular to the first side of the ceramic substrate can be made alternatively or in addition to the arrangement parallel to the first side of the ceramic substrate.

[0021] Advantageously, the surface area of ​​the contact pads can be further enlarged by a combination of the parallel and lateral arrangement of the surface areas.

[0022] In one example, the first and / or second region uncovered by the insulation layer is formed in the form of an opening in the material of the insulation layer.

[0023] Advantageously, the material of the insulating layer surrounds the opening, on which the contact pads can be arranged. In one example, the material of the contact pads extends through the openings to electrically contact the terminals of the resistance element.

[0024] In an alternative example, the first and second regions uncovered by the insulation layer are arranged at two opposite ends of the ceramic substrate, and the two terminals are each arranged at one of the opposite ends of the ceramic substrate.

[0025] In this example, the insulation layer is arranged in a central region on the ceramic substrate and extends only to the terminals of the resistor element. The openings are arranged on the sides of the insulation layer in this example.

[0026] In a further example, the insulation layer completely covers the first side of the ceramic substrate with the resistance element arranged thereon, and the first and / or the second region uncovered by the insulation layer is arranged at least partially on the ceramic substrate perpendicular to the first side of the ceramic substrate, and the first and / or the second terminal is each arranged on one of two opposite ends of the ceramic substrate perpendicular to the first side of the ceramic substrate.

[0027] In another example, the ceramic substrate has a maximum length of 10 mm, a maximum width of 5 mm and a maximum height of 3 mm.

[0028] In another example, the insulating layer comprises a glass or a glass-ceramic material.

[0029] Advantageously, a glass ceramic can be used to create an insulation layer with very good insulation properties, which can be made very thin due to the good insulation properties.

[0030] In a further example, the first and second surface regions are adapted for wedge bonding of aluminum heavy wire, in particular aluminum heavy wire with a diameter of greater than or equal to 25 µm.

[0031] In another example, the sinterable metallization comprises a silver-palladium metallization, and / or the ceramic substrate comprises an Al2O3 ceramic.

[0032] In a further example, the metal layer comprises a structuring, a PT100 or PT1000 resistance element, in particular a Pt thin-film or thick-film resistance element with trimming section, and is adapted to measure a temperature, and wherein the structuring of the metal layer extends meander-shaped between the first terminal and the second terminal.

[0033] In another example, the metal layer comprises a material having a temperature coefficient of less than 500 ppm K -1< at room temperature, in particular metal alloys containing chromium, nickel, iron, zinc, silver or palladium.

[0034] The invention also proposes a printed circuit board with at least one resistance component according to the invention arranged thereon.

[0035] Further features and advantages of the invention will become apparent from the following description, in which preferred embodiments of the invention are explained with reference to schematic drawings.

[0036] Showing: Figures 1a, 1b, 1c, 1d are schematic views of a structure of a resistance element according to a first embodiment of the invention; and Figures 2a, 2b, 2c, 2d are schematic views of a structure of a resistance element according to a second embodiment of the invention.

[0037] Figure 1ashows a ceramic substrate 1 in the shape of a cuboid according to a first embodiment of the invention. In the embodiment shown, the ceramic substrate 1 has a maximum length of 10 mm, a maximum width of 5 mm, and a maximum height of 3 mm. In the embodiment shown, the ceramic substrate 1 can comprise one or more materials from the group: Al2O3, AlSiC, AIN, B4C, BN, PBN, MgO, SiC, SiSiC, SSiC, Si3N4, YSZ, or PZT. A sinterable metallization 3 is arranged on one of the first sides, or the top side of the ceramic substrate 1, which is opposite the second side. In the embodiment shown, the sinterable metallization 3 can comprise one or more materials from the group: NiAu, NiPdAu, AgPd, AuPd, Cu, Au, or Ag, and can be arranged over the entire surface of the second side of the ceramic substrate 1.

[0038] Figure 1b shows that previously in Figure 1ashown ceramic substrate 1 with a resistance element formed as a structured metal layer 5, which is arranged on the first side of the ceramic substrate 1 with a first terminal 7a and a second terminal 7b.

[0039] The metal layer 5 is, as in Figure 1b shown, configured as a conductor track that runs in a meandering manner between its ends, which are formed by the first terminal 7a and the second terminal 7b, and has a defined resistance value and temperature coefficient at a specific temperature. In the embodiment shown, the first terminal 7a and the second terminal 7b are each shown as a strip-shaped conductor track section. In further embodiments, the first and second terminals can also be formed simply by the conductor track ends of the meandering conductor track.

[0040] Figure 1c shows the previously in Figure 1bshown arrangement with an insulation layer 9 on the metal layer 5 and the first side of the ceramic substrate 1. As shown in the Figure 1c As shown, a first region 8a on the first terminal 7a and a second region 8b on the second terminal 7b are uncovered by the insulation layer 9. In the embodiment shown, the first region 8a and the second region 8b are opposite one another and the insulation layer 9 is formed by a glass or glass-ceramic material.

[0041] Figure 1d shows the previously in Figure 1cThe arrangement shown includes a first contact pad 11a that electrically contacts the first terminal 7a via the first region 8a, and a second contact pad 11b that electrically contacts the second terminal 7b via the second region 8b. The material of the respective contact pads 11a, 11b contacts the respective terminal 7a, 7b to achieve an electrical connection of the contact pads 11a, 11b to the terminals 7a, 7b.

[0042] As it is in the Figure 1d As shown, the contact pads 11a, 11b cover a region of the surface of the insulating layer 9 that runs parallel to the first side of the ceramic substrate 1 with the resistance element arranged thereon. In the embodiment shown, the contact pads 11a, 11b also cover a region of the surface of the insulating layer 9 that runs perpendicular to the first side of the ceramic substrate 1.

[0043] The Figures 2a, 2b, 2c, 2dshow further schematic views of a structure of a resistance element according to a second embodiment of the invention.

[0044] The Figures 2a and 2b correspond to those shown previously Figures 1a and 1b .

[0045] In the Figure 2c the insulation layer is arranged substantially over the entire surface of the first side of the ceramic substrate 1' and a recess 8a', 8b', in the form of an opening, is arranged in the material of the insulation layer 9' in order to enable electrical contacting of the underlying terminals 7a', 7b'.

[0046] As it is in the Figure 1cAs shown, a first region 8a' on the first terminal 7a' and a second region 8b' on the second terminal 7b' are uncovered by the insulating layer 9'. In the embodiment shown, the first region 8a' and the second region 8b' are opposite each other, and the insulating layer 9' is formed by a glass or glass-ceramic material.

[0047] The terminals 7a', 7b' can be contacted via an electrical conductor that extends through the openings and is in electrical contact with the material of the contact pads 11a', 11b'. Alternatively, a portion of the material of the contact pads 11a', 11b' can extend through the openings and be in direct electrical contact with the terminals 7a', 7b'.

[0048] As it is in the Figure 2dAs shown, the contact pads 11 a`, 11b' cover a region of the surface of the insulation layer 9' which runs parallel to the first side of the ceramic substrate 1' with the resistance element arranged thereon.

[0049] In a further embodiment (not shown), the resistance layer is formed over the entire surface of the substrate and without structuring. List of reference symbols

[0050] 1, 1' ceramic substrate 3, 3' sinterable metallization 5, 5' metal layer 7a, 7a' first connection 7b, 7b' second connection 8a, 8a' first region 8b, 8b' second region 9, 9' insulation layer 11a, 11a' first contact pad 11b, 11b' second contact pad

Claims

1. A resistor component for surface mounting on a printed circuit board, comprising: a ceramic substrate (1, 1') with a first side and an opposite second side, wherein a sinterable metallization (3, 3') is arranged at least in some regions on the second side; a resistance element having a metal layer (5, 5') arranged at least in some regions on the first side of the ceramic substrate (1, 1') with a first connection (7a, 7a') and a second connection (7b, 7b'); an insulation layer (9, 9') arranged at least in some regions on the resistance element and the ceramic substrate (1, 1'), wherein a first region (8a, 8a') on the first connection (7a, 7a') and a second region (8b, 8b') on the second connection (7b, 7b') remain uncovered by the insulation layer (9, 9'); and a first contact pad (11a, 11a') that electrically contacts the first connection (7a, 7a') via the first region (8a, 8a') and a second contact pad (11b, 11b') that electrically contacts the second connection (7b, 7b') via the second region (8b, 8b'); characterized in that the first contact pad (11a, 11a') covers a first surface area of the insulation layer (9, 9') at least in some regions and the second contact pad (11b, 11b') covers a second surface area of the insulation layer (9, 9') at least in some regions, and in that the first contact pad (11a, 11a') and the second contact pad (11b, 11b') are arranged on the insulation layer (9, 9') such that they are spatially separated from one another.

2. The resistor component according to claim 1, characterized in that the first and the second surface area collectively cover at least 70 % of a total surface of the insulation layer (9, 9') on the first side of the ceramic substrate (1, 1').

3. The resistor component according to claim 1 or 2, characterized in that the first and the second surface area cover at least in some regions a surface of the insulation layer (9, 9'), which extends parallel to the first side of the ceramic substrate with the resistance element arranged thereon.

4. The resistor component according to one of the preceding claims, characterized in that the first and the second surface area cover at least in some regions a surface of the insulation layer (9), which extends perpendicular to the first side of the ceramic substrate (1) with the resistance element arranged thereon.

5. The resistor component according to one of the preceding claims, characterized in that the first region (8a') and / or the second region (8b') not covered by the insulation layer (9') is realized in the form of an opening in the material of the insulation layer (9').

6. The resistor component according to one of claims 1 to 4, characterized in that the first region (8a) and the second region (8b) not covered by the insulation layer (9) are arranged on two opposite ends of the ceramic substrate (1) and the first connection (7a) and the second connection (7b) are respectively arranged on one of the two opposite ends.

7. The resistor component according to one of claims 1 to 4, characterized in that the insulation layer (9') completely covers the first side of the ceramic substrate (1') with the resistance element arranged thereon, in that the first region (8a') and / or the second region (8b') not covered by the insulation layer (9') is arranged at least in some regions on the ceramic substrate (1') perpendicular to the first side of the ceramic substrate (1'), and in that the first connection and / or the second connection is respectively arranged on one of two opposite ends of the ceramic substrate perpendicular to the first side of the ceramic substrate (1, 1').

8. The resistor component according to one of the preceding claims, characterized in that the ceramic substrate (1, 1') has a maximum length of 10 mm, a maximum width of 5 mm and a maximum height of 3 mm.

9. The resistor component according to one of the preceding claims, characterized in that the insulation layer (9, 9') comprises a glass or glass ceramic material.

10. The resistor component according to one of the preceding claims, characterized in that the first and the second surface area are adapted for wedge bonding of aluminum thick wire, particularly aluminum thick wire with a diameter greater than or equal to 25 µm.

11. The resistor component according to one of the preceding claims, characterized in that the sinterable metallization (3, 3') comprises a silver-palladium metallization and / or the ceramic substrate (1, 1') comprises an Al2O3 ceramic.

12. The resistor component according to one of the preceding claims, characterized in that the metal layer (5, 5') comprises a structuring, a PT100 or PT1000 resistance element, particularly a Pt thin layer or thick layer resistance element with trimming section, and is adapted for measuring a temperature, and in that the structuring of the metal layer (5, 5') extends between the first connection (7a, 7a') and the second connection (7b, 7b') in a meandering manner.

13. The resistor component according to one of claims 1 to 11, characterized in that the metal layer (5, 5') comprises a material with a temperature coefficient of less than 500 ppm K-1 at room temperature, particularly metal alloys containing chromium, nickel, iron, zinc, silver or palladium.

14. A printed circuit board with at least one resistor component according to one of the preceding claims arranged thereon.