Resistor, manufacturing panel, circuit board assembly, and production method

Abstract

The invention relates to a resistor (1) comprising two plate-type connection parts (4, 5) which are made of a conductor material and comprising a plate-type resistor element (3) which is sandwiched therebetween and which is made of a resistor material, such that the electric current (I) flows through the plate-type resistor element (3) transversely to the plate plane. According to the invention, the upper and lower contact surfaces (6, 7) between the resistor element (3) and the upper and lower connection parts (4, 5), respectively, are delimited by an upper and a lower lacquer frame (10, 11), respectively, made of an electrically insulating solder resist lacquer, the upper and lower lacquer frames (10, 11) being applied to the upper side and lower side, respectively, of the resistor element (3) and framing the upper and lower connection parts (4, 5), respectively, and thereby determining the surface area of the upper and lower contact surfaces (6, 7), respectively. The invention also relates to a manufacturing panel having a plurality of non-separated resistors (1) according to the invention, to a printed circuit board assembly having a resistor (1) according to the invention, and to a production method for producing a resistor (1) according to the invention.

Description

[0001] DESCRIPTION

[0002] Resistance, manufacturing benefits, circuit board layout and manufacturing process

[0003] Technical field of the invention

[0004] The invention relates to a resistor, in particular a low-resistance current-sensing resistor for measuring an electric current. The invention further relates to a manufacturing panel with several such non-isolated resistors. In addition, the invention also includes a printed circuit board arrangement with such a resistor and a manufacturing method for producing such a resistor.

[0005] Background of the invention

[0006] Low-resistance current-sensing resistors, also known as "shunts," are known from the prior art (e.g., EP 0 605 800 Al) and can be used for current measurement using the four-wire technique. The electric current to be measured is passed through the low-resistance current-sensing resistor, and the resulting voltage drop across the resistor is measured. According to Ohm's law, this voltage drop is a measure of the electric current flowing through the resistor.

[0007] Figure 1 shows a perspective view of a known design of such a low-resistance current-sensing resistor 1. The current-sensing resistor 1 has a plate-shaped support element 2 made of an electrically insulating material (e.g., ceramic). A similarly plate-shaped resistance element 3, made of a resistance material (e.g., Manganin®), is mounted on the upper surface of the plate-shaped support element 2. A terminal 4 made of a conductor material (e.g., copper) is mounted on the upper surface of one side edge of the plate-shaped support element 2. This terminal 4 serves to introduce an electric current I to be measured into the current-sensing resistor 1. Another terminal 5 made of a conductor material (e.g., copper) is mounted on the upper surface of the opposite side edge of the plate-shaped support element 2. This terminal 5 serves to discharge the electric current I to be measured back out of the current-sensing resistor 1.The plate-shaped resistor 3 extends between the two terminals 4 and 5 and makes electrical contact with them, so that the electric current I to be measured is introduced into the current-sensing resistor 1 via terminal 4, then flows through the resistor 3, and finally exits the current-sensing resistor 1 via terminal 5. The voltage drop across the resistor 3 can then be measured at the two terminals 4 and 5. According to Ohm's law, this voltage is a measure of the electric current I flowing through the current-sensing resistor 1. This design of the low-resistance current-sensing resistor 1 is also called a horizontal shunt because the electric current I to be measured flows horizontally, parallel to the plane of the plate-shaped resistor 1.

[0008] A problem with this design of the current-sensing resistor 1 as a horizontal shunt is that the structuring process (e.g., etching) during its manufacture leads to relatively large variations in the cross-section of the plate-shaped resistor element 3. These variations in the cross-section of the plate-shaped resistor element 3, in turn, lead to corresponding variations in the resistance value of the current-sensing resistor 1, necessitating subsequent adjustment of the resistance value.

[0009] Figures 2A and 2B show another known design of a low-resistance current-sensing resistor 1, which partially corresponds to the design described above and shown in Figure 1. Therefore, to avoid repetition, reference is made to the preceding description of Figure 1, using the same reference numerals for corresponding details. A special feature of this design is that the two plate-shaped terminal parts 4, 5 and the plate-shaped resistive element 3 are arranged one above the other in a sandwich-like manner, so that the electric current I to be measured flows vertically through the current-sensing resistor 1 at right angles to the plane of the plates. This is why this design is also called a vertical shunt. The plate-shaped resistive element 3 is connected to the upper terminal part 4 via an upper contact surface 6 and to the lower terminal part 5 via a lower contact surface 7.Figures 2A and 2B further show a printed circuit board (PCB) 8, with the current-sensing resistor 1 mounted on the top side of the PCB 8 via a solder connection 9. To avoid confusion, it should also be noted that the current I to be measured is introduced at the top of the upper terminal 4, which is not shown here for simplicity. However, it is also possible for the current I to be measured to flow in the opposite direction through the current-sensing resistor 1, i.e., from bottom to top in the drawing.

[0010] A problem with this design of the current-sensing resistor 1 as a vertical shunt is that the solder joint 9 is subject to considerable variation in its lateral dimensions. This is particularly problematic when the resistance value of the current-sensing resistor 1 is very small, since then the effective resistance value of the current-sensing resistor 1, including the contact resistance of the solder joint 9, depends relatively strongly on the wetting area with which the solder joint 9 wets the underside of the lower terminal 5 with solder. Figure 2A shows a relatively large contact area with a correspondingly low contact resistance of the solder joint 9, while Figure 2B shows a relatively small contact area with a correspondingly high contact resistance of the solder joint 9.Furthermore, with a low resistance value of the current-sensing resistor 1, the current would flow mainly through the part of the resistive element 3 that corresponds to the solder-wetted area of ​​the adjacent terminal part 4 or 5. This would reduce the effective conductor cross-section of the current-sensing resistor 1 with a relatively small wetted area compared to a relatively large wetted area, thus increasing the resistance value accordingly.

[0011] Description of the invention

[0012] The invention therefore aims to create a correspondingly improved resistor. Furthermore, the invention aims to simplify the manufacture of such a resistor.

[0013] This problem is solved by a resistor according to the invention, a manufacturing panel with several non-isolated resistors, a printed circuit board arrangement according to the invention, and a manufacturing method according to the independent claims.

[0014] The resistor according to the invention is preferably also a low-resistance current measuring resistor, however, the invention also claims protection in principle for resistors that are not low-resistance, but have a larger resistance value and therefore are not suitable for current measurement according to the four-wire technique.

[0015] The current measuring resistor according to the invention essentially corresponds to the known design of a vertical shunt described above, as shown in Figures 2A and 2B.

[0016] Thus, the resistor according to the invention initially has, in accordance with the known resistor described above, a plate-shaped upper connection part made of a conductor material (e.g. copper), wherein the upper connection part can serve to introduce the electric current to be measured into the resistor or to introduce the electric current to be measured out of the resistor.

[0017] Furthermore, the resistor according to the invention also has a plate-shaped lower connection part made of a conductor material (e.g. copper), in accordance with the prior art, wherein the lower connection part can optionally serve to introduce the electric current to be measured into the resistor or to direct the electric current to be measured out of the resistor.

[0018] In the resistor according to the invention, a plate-shaped resistive element made of a resistive material (e.g., Manganin®) is arranged in a sandwich-like manner between the upper and lower terminal parts. The resistive element is electrically and mechanically connected to the upper terminal part via an upper contact surface and to the lower terminal part via a lower contact surface, so that during operation the electric current flows transversely to the plane of the plate through the plate-shaped resistive element.

[0019] The resistor according to the invention differs from the known vertical shunt described above in that the upper and lower contact surfaces of the resistive element are delimited by an upper and lower lacquer frame made of an electrically insulating solder mask. This lacquer frame is applied to the top and bottom surfaces of the resistive element, respectively, and frames the upper and lower terminals, thereby defining the area of ​​the upper and lower contact surfaces. The application of the lacquer frames allows for very precise adjustment of the contact surface area and thus of the resistor's resistance value. Furthermore, the lacquer frames can be applied to a production tray containing several resistors that have not yet been separated, eliminating the need to individually adjust the resistance value of each resistor once it is separated from the tray.

[0020] It should be noted that in the preferred embodiment of the invention, lacquer frames are preferably applied to both the top and the bottom of the plate-shaped resistive element. However, the invention also claims protection for a resistor in which such a lacquer frame is applied only to the top or only to the bottom in order to adjust the surface area of ​​the contact area between the plate-shaped resistive element and the upper or lower connecting part, respectively.

[0021] In the preferred embodiment of the invention, the upper or lower lacquer frame extends outwards in the plane of the plate to the edge of the resistor in order to prevent a lateral short circuit via the solder when applying solder for a soldered joint. If too much solder is used, it could extend outwards from the upper or lower terminal part and cause a short circuit there. Such a short circuit is largely prevented if the upper or lower lacquer frame extends laterally outwards to the edge of the resistor.

[0022] Furthermore, it should be noted that the connection parts preferably extend upwards or downwards beyond the respective lacquer frame in order to form a collection volume for solder when mounted on a printed circuit board, both laterally next to the connection part and vertically between the circuit board and the lacquer frame. For example, the connection part can extend downwards or upwards beyond the respective lacquer frame by at least 5 pm, 10 pm, 15 pm, 20 pm, or 25 pm.

[0023] It should also be mentioned that the upper or lower painted frame preferably abuts the upper or lower connecting part without gaps on the inside.

[0024] Furthermore, it should be mentioned that the upper paint frame and the lower paint frame preferably have the same internal cross-section, so that the upper contact surface and the lower contact surface of the resistance element to the upper and lower connection parts are preferably the same size.

[0025] It has already been mentioned above that the resistor according to the invention is preferably a low-resistance current-sensing resistor, which, for example, has a resistance value of at most 500 mΩ, 200 mΩ, 100 mΩ, 50 mΩ, 10 mΩ, 1 mΩ, 500 pΩ, 300 pΩ, 200 pΩ, 100 pΩ or at most 50 pΩ. However, the invention is not limited to these resistance ranges with regard to the resistance value of the resistor according to the invention.

[0026] Furthermore, it should be mentioned that the resistance is preferably relatively small and has a cross-sectional area of ​​no more than 100 mm² in its plane. 2 , 50 mm 2 , 25 mm 2 , 10 mm 2 , or 5 mm 2 or at most 2 mm 2The invention, however, is not limited to the aforementioned cross-sectional areas with regard to the size of the resistor. Furthermore, it should be noted that the resistor has a certain thickness D perpendicular to the plane of the plate and a certain minimum length L in the plane of the plate, wherein the ratio between the thickness D and the minimum length L is preferably at most 1 / z or 74. However, the invention is not limited to this ratio between thickness and length.

[0027] The conductor material of the connecting parts can be, for example, copper, a copper alloy, aluminum, or an aluminum alloy; however, the conductor material should have a lower specific electrical resistance than the resistive element. Furthermore, the conductor material should have a specific electrical resistance of less than 0.5 mm². 2 / m, 0.2 Q.mm 2 / m, 0.1 Q.mm2 / m, 0.05 Q.mm 2 / m or 0.03 mm² 2 / m.

[0028] Furthermore, it should be generally mentioned that the upper connection part, the resistive element, and the lower connection part are preferably flat. However, a curved, plate-shaped design of the resistor according to the invention is also conceivable in principle.

[0029] In the preferred embodiment of the invention, the resistance material of the plate-shaped resistance element is a resistance alloy, wherein, for example, the following resistance alloys are suitable:

[0030] • a copper-manganese alloy, in particular a copper-manganese-nickel alloy or a copper-manganese-aluminium alloy or a copper-manganese-tin alloy,

[0031] • a nickel-chromium alloy, in particular a nickel-chromium-aluminium-silicon alloy,

[0032] • a copper-nickel alloy,

[0033] • a copper-silver alloy,

[0034] • a nickel-copper alloy,

[0035] • a nickel-iron alloy.

[0036] However, the invention is not limited to the resistance alloys mentioned above as examples.

[0037] Furthermore, it should be generally mentioned that the resistor according to the invention is preferably an SMD resistor (SMD: surface-mounted device) designed for surface mounting on a printed circuit board. The solder mask in the resistor according to the invention should be electrically insulating. Moreover, the solder mask is preferably structurable (e.g., photostructurable), in particular as a so-called "liquid photoimageable solder mask" (LPSM) or as a "dry-film photoimageable solder mask" (DFSM). For example, the solder mask could also be applied by an inkjet process.

[0038] In the preferred embodiment of the invention, the upper connection part and / or the lower connection part have a certain conductor thickness L perpendicular to the plane of the plate, while the upper connection part and / or the lower connection part have a certain cross-sectional area A in the plane of the plate, preferably with the following ratio: L / 7 < 1, Yi or 73.

[0039] Furthermore, it should generally be mentioned that the upper or lower coating frame, perpendicular to the plane of the plate, preferably has a layer thickness of less than 2 mm, 1 mm, 500 pm, 250 pm, 100 pm or 50 pm, wherein the layer thickness of the upper coating frame and the lower coating frame is preferably the same.

[0040] Furthermore, it should generally be mentioned that the upper or lower paint frame is preferably applied directly to the top or bottom of the plate-shaped resistance element, i.e. without an intermediate layer between the paint frame and the plate-shaped resistance element.

[0041] Furthermore, it should also be mentioned that the solder mask preferably has a lower wettability with respect to the liquid solder than the conductor material of the upper and lower terminals. This prevents the liquid solder from spreading laterally from the lower or upper terminals outwards to the edge of the resistor.

[0042] The resistor according to the invention has been described above as a finished passive component. However, it has already been mentioned that the lacquer frames can be applied to a manufacturing panel of the resistor element, wherein the manufacturing panel comprises several non-isolated resistors. The invention therefore also claims protection for such a manufacturing panel comprising several non-isolated resistors according to the invention. For example, the manufacturing panel according to the invention can comprise more than 4, 10, 20, or 50 non-isolated resistors. Furthermore, the invention also claims protection for a printed circuit board arrangement comprising a printed circuit board and a resistor according to the invention, wherein the resistor is preferably connected to the printed circuit board by a soldered connection.

[0043] The resistor is preferably arranged on the top side of the printed circuit board, with the solder joint between the resistor and the circuit board preferably contacting the entire surface of the lower terminal part of the resistor on its underside. The solder joint between the resistor and the circuit board, perpendicular to the plane of the board, preferably has a layer thickness of at most 1 mm, 500 pm, 200 pm, 100 pm, 50 pm, 20 pm, or 10 pm.

[0044] In addition to the resistor according to the invention as a finished component, the manufacturing process, and the printed circuit board arrangement described above, the invention also claims protection for a corresponding manufacturing process. The individual process steps of the manufacturing process according to the invention are already evident from the preceding description of the resistor according to the invention, so that a separate description of the individual process steps can largely be dispensed with.

[0045] However, it should be noted that the upper or lower lacquer frame is preferably applied to the plate-shaped resistive element before the upper or lower connecting part is applied to the resistive element. This is advantageous because the inner cross-section of the upper or lower lacquer frame then defines the lateral dimensions of the upper or lower connecting part and thus the surface area of ​​the upper or lower contact surface.

[0046] Furthermore, it should be mentioned that when manufacturing the plate-shaped resistive element from a foil or a sheet, the thickness of the plate-shaped resistive element can vary, which, without compensation, leads to corresponding component variations in the resistance value. The manufacturing method according to the invention therefore preferably provides that the thickness of the plate-shaped resistive element is measured. Subsequently, a target value for the area of ​​the upper or lower contact surface between the upper or lower connection part on the one hand and the plate-shaped resistive element on the other is calculated, depending on the measured thickness of the plate-shaped resistive element and also depending on the desired resistance value. The area of ​​the upper or lower contact surface is then determined by the thickness of the plate-shaped resistive element.The lower contact surface is then specified according to the calculated target value in order to compensate for component variations in the thickness of the plate-shaped resistance element.

[0047] The thickness of the plate-shaped resistive element can be measured directly or indirectly. In the indirect measurement of the plate-shaped resistive element's thickness, the electrical surface resistance of the plate-shaped resistive element is preferably measured. The thickness of the plate-shaped resistive element can then be calculated from the measured electrical surface resistance of the plate-shaped resistive element and the specific electrical resistance of the resistive material of the plate-shaped resistive element.

[0048] Furthermore, it should be mentioned that the surface area of ​​the upper or lower contact surface is preferably adjusted by adjusting the inner cross-section of the upper or lower paint frame.

[0049] Furthermore, it should be mentioned that the upper or lower lacquer frame can preferably be applied photolithographically to the top or bottom of the plate-shaped resistive element, which can be done with high positioning accuracy. This is advantageous because it also allows the contact area between the plate-shaped resistive element and the upper or lower connection part to be adjusted with corresponding precision. For example, the upper or lower lacquer frame can be applied to the resistive element with a positional tolerance of no more than 100 pm, 50 pm, 25 pm, 10 pm, or 5 pm to precisely match the resistance value of the resistor.

[0050] Furthermore, it should be generally mentioned that to adjust the resistance value of the resistor, only the surface area of ​​the upper or lower contact surface is set by appropriately specifying the size of the lacquer frames. Therefore, in the manufacturing process according to the invention, it is generally no longer necessary to adjust the resistor element itself to set the desired resistance value.

[0051] It should also be mentioned in general that the invention is not limited to rectangular shapes with regard to the shape of the connecting parts, the resistance element, the current measuring resistor as a whole and the paint frame.

[0052] It should also be noted that the painted frame can have ribs. With a single rib, a painted frame can define two connection parts, while a painted frame with two ribs can define three connection parts.

[0053] Finally, it should also be noted that more than one connection part can be arranged on the top and / or bottom of the resistive element. Accordingly, several lacquer frames can also be arranged on the top or bottom of the resistive element. However, the invention is described above and below for a variant in which exactly one connection part is arranged on the top and exactly one connection part on the bottom of the resistive element, so that there is also exactly one lacquer frame on the top and exactly one lacquer frame on the bottom of the resistive element. Within the scope of the complete description, however, this can be modified to include multiple connection parts and, accordingly, multiple lacquer frames on the top and / or bottom.

[0054] Other advantageous embodiments of the invention are characterized in the dependent claims or are explained in more detail below together with the description of the preferred embodiments of the invention.

[0055] Brief description of the drawings

[0056] Figure 1 shows a perspective view of the known design of a so-called horizontal shunt described at the beginning.

[0057] Figures 2A and 2B show a cross-sectional view of the previously described known design of a so-called vertical shunt.

[0058] Figures 3A and 3B show cross-sectional views of the design of a vertical shunt according to the invention.

[0059] Figure 4 shows a top view of the vertical shunt according to Figures 3A and 3B.

[0060] Figure 5 shows a flowchart to illustrate the manufacturing process according to the invention. Figure 6 shows a schematic representation of a manufacturing panel comprising numerous non-isolated current-measuring resistors according to the invention.

[0061] Figure 7 shows a variation of Figure 4.

[0062] Detailed description of the drawings

[0063] The exemplary embodiment of a current-sensing resistor 1 according to the invention, as shown in Figures 3A, 3B and 4, is described below. This resistor is also a so-called vertical shunt, similar to those known from the prior art according to Figures 2A and 2B. To avoid repetition, reference is made to the preceding description of Figures 2A and 2B, using the same reference numerals for corresponding details.

[0064] A special feature of the current-sensing resistor 1 according to the invention is that the two connecting parts 4, 5 do not extend over the entire surface of the plate-shaped resistive element 3, but are bounded externally by an upper lacquer frame 10 and a lower lacquer frame 11, respectively. The two lacquer frames 10, 11 each consist of an electrically insulating solder mask and are applied directly to the top and bottom surfaces of the plate-shaped resistive element 3, respectively, without an intermediate layer. The lacquer frames 10, 11 thus frame the upper connecting part 4 and the lower connecting part 5, respectively, and thereby determine the area of ​​the upper contact surface 6 and the lower contact surface 7, respectively.

[0065] It should be noted that the lacquer frames 10, 11 can be applied photolithographically, which enables high positioning accuracy with a horizontal positional tolerance of a few micrometers. This high positioning accuracy in the application of the lacquer frames 10, 11, in turn, allows for highly precise adjustment of the surface area of ​​the contact surfaces 6, 7, which in turn allows the resistance value of the current-sensing resistor 1 to be set very accurately.

[0066] It should be noted that the current-measuring resistor 1 has a certain thickness D perpendicular to the plane of the plate and a certain minimum length L in the plane of the plate, where the ratio between the thickness D and the minimum length L is at most / z.

[0067] A comparison of Figures 3A and 3B shows that the lateral extent of the solder joint 9 has almost no influence on the wetting area of ​​the solder joint 9 on the lower terminal part 4. This is important so that the contact resistance of the solder joint 9 is subject to as little variation as possible.

[0068] Furthermore, the drawings show that the upper connection part 4 projects upwards beyond the upper lacquer frame 10. Similarly, the lower connection part 5 projects downwards beyond the lower lacquer frame 11. This creates a collection volume 12 for solder between the circuit board 8 and the lower lacquer frame 11, laterally adjacent to the lower connection part 5, preventing the solder from flowing outwards laterally without limit.

[0069] The following describes the flowchart according to Figure 5, which explains the manufacturing process according to the invention, with reference also made to Figure 6.

[0070] In a first step S1, a plate made of a resistance material is provided.

[0071] In a second step S2, the plate thickness of the plate made of the resistance material is then measured, since the plate thickness has an impact on the resistance value of the finished resistor.

[0072] In the next step S3, the appropriate surface area of ​​the contact surfaces 6, 7 is calculated and two are selected depending on the measured plate thickness and also depending on the desired resistance value.

[0073] In the next step S4, a manufacturing panel 13 is then cut from the plate, the manufacturing panel being shown in Figure 6 and serving in this embodiment to produce a total of 25 current-measuring resistors 1.

[0074] In the next step S5, the coating frames 10, 11 are applied to both the top and bottom surfaces of the production panel 3, according to the appropriate surface area calculated in step S3. The coating frames 10, 11 are applied photolithographically, which allows for high positioning accuracy.

[0075] After the coating frames 10, 11 have been applied, the connecting parts 4, 5 are applied in the next step S6, each within the coating frames 10, 11, so that the size of the contact surfaces 6, 7 is determined by the inner size of the coating frames 10, 11. In the next step S7, the individual current-measuring resistors 1 are then separated from the production batch 13. For this purpose, the production batch 13 can be separated along separation lines 14, 15.

[0076] Finally, Figure 7 shows a modification of Figure 4, so to avoid repetition, reference is made to the preceding description.

[0077] A special feature of this embodiment is that the paint frame 4 has two webs 16, 17, so that the paint frame 4 defines a total of three separate connection parts 4.1, 4.2, 4.3.

[0078] The invention is not limited to the preferred embodiments described above. Rather, various variants and modifications are possible within the scope of the invention, which also make use of the inventive concept and therefore fall within the scope of protection. In particular, the invention also claims protection for the subject matter and the features of the dependent claims independently of the referenced claims and especially even without the features of the main claim. The invention thus comprises various aspects of the invention that enjoy independent protection.

[0079] Advantages of the invention

[0080] The invention offers several advantages, which can be summarized as follows:

[0081] • The lateral expansion of the solder joint between the resistor and the circuit board has almost no influence on the through-resistance of the solder joint between the circuit board and the resistor.

[0082] • The surface area of ​​the contact surfaces between the plate-shaped resistance element on the one hand and the upper or lower connection part on the other hand can be adjusted with high precision, for example by photolithographic structuring of the paint frames.

[0083] • The lacquered frames prevent a lateral short circuit caused by excess solder on the resistor.

[0084] • The lacquer frames allow for the formation of a solder collection volume to the side of the connection part, enabling reproducibly thin solder layers. Reference numeral list

[0085] 1 current measuring resistor

[0086] 2 Support element made of an electrically insulating material (e.g. ceramic)

[0087] 3 Resistance elements made of a resistance material

[0088] 4 Copper connection part for introducing current into the current measuring resistor

[0089] 4.1-4.3 Copper connection parts for introducing current into the current measuring resistor

[0090] 5 Copper connection part for diverting the current from the current measuring resistor

[0091] 6 Upper contact surface between the upper connection part and the resistance element

[0092] 7 Lower contact surface between the lower connection part and the resistance element

[0093] 8 circuit boards

[0094] 9. Solder connection between the resistor and the circuit board

[0095] 10 Upper lacquer frame made of electrically insulating solder resist

[0096] 11 Lower lacquer frame made of electrically insulating solder resist

[0097] 12 Collection volumes for collecting solder between the lower connection part, the circuit board and the lower paint frame

[0098] 13 Manufacturing benefits with multiple non-isolated current measuring resistors

[0099] 14, 15 Separation lines for separating the current measuring resistors from the manufacturing component

[0100] 16, 17 struts of the lacquered frame

[0101] D Thickness of the current-sensing resistor perpendicular to the plane of the plate

[0102] I Electric current through the current measuring resistor

[0103] L Maximum length of the current-sensing resistor in the plane of the plate

[0104] PCB Printed Circuit Board (PCB)

Claims

Claims 1. Resistor (1), in particular a low-resistance current-measuring resistor (1) for measuring an electric current (I), comprising a) at least one plate-shaped upper connection part (4) made of a conductor material, in particular for introducing the electric current (I) to be measured into the resistor (1), b) at least one plate-shaped lower connection part (5) made of a conductor material, in particular for introducing the electric current (I) to be measured out of the resistor (1), c) a plate-shaped resistance element (3) made of a resistance material, wherein the plate-shaped resistance element (3) is arranged in a sandwich-like manner between the at least one upper connection part (4) and the at least one lower connection part (5), such that the electric current (I) flows transversely to the plane of the plate through the plate-shaped resistance element (3), characterized in thatd) that at least one upper contact surface (6) between the at least one upper terminal part (4) and the resistive element (3) is bounded by an upper lacquer frame (10) made of an electrically insulating solder mask, wherein the upper lacquer frame (10) is applied to the top of the resistive element (3) and frames the upper terminal part (4) and thereby determines the area of ​​the upper contact surface (6), and / or e) that at least one lower contact surface (7) between the at least one lower terminal part (5) and the resistive element (3) is bounded by a lower lacquer frame (11) made of an electrically insulating solder mask, wherein the lower lacquer frame (11) is applied to the underside of the resistive element (3) and frames the lower terminal part (5) and thereby determines the area of ​​the lower contact surface (7).

2. Resistor (1) according to claim 1, characterized in that a) the upper lacquer frame (10) extends outwards in the plane of the plate to the edge of the resistor (1) in order to prevent a lateral short circuit via the solder when applying solder for a solder joint (9), and / or b) that the lower lacquer frame (11) extends outwards in the plane of the plate to the edge of the resistor (1) in order to prevent a lateral short circuit via the solder when applying solder for a solder joint (9).

3. Resistor (1) according to one of the preceding claims, characterized in that a) the lower connection part (5) projects downwards beyond the lower lacquer frame (11), in particular by at least 5 pm, 10 pm, 15 pm, 20 pm or 25 pm, in order to form a collection volume for solder laterally next to the lower connection part (5) between the lower lacquer frame (11) and the circuit board (8) below it when mounted on the top side of a circuit board (8), and / or b) that the upper connection part (4) projects upwards beyond the upper lacquer frame (10), in particular by at least 5 pm, 10 pm, 15 pm, 20 pm or 25 pm, in order to form a collection volume for solder laterally next to the upper connection part (4) between the upper lacquer frame (10) and the circuit board (8) above it when mounted on the underside of a circuit board (8).

4. Resistor (1) according to one of the preceding claims, characterized in that a) the upper paint frame (10) is fully adjacent to the upper connection part (4) on the inside, and / or b) the lower paint frame (11) is fully adjacent to the lower connection part (5) on the inside, and / or c) the upper paint frame (10) and the lower paint frame (11) have the same internal cross-section, so that the upper contact surface (6) and the lower contact surface (7) are substantially the same size.

5. Resistor (1) according to one of the preceding claims, characterized in that a) the resistor (1) has a resistance value of at most 500 mΩ, 200 mΩ, 100 mΩ, 50 mΩ, 10 mΩ, 1 mΩ, 500 pΩ, 300 pΩ, 200 pΩ, 100 pΩ or at most 50 pΩ, and / or b) the resistor (1) has a cross-sectional area of ​​at most 100 mm² in its plane. 2 , 50 mm 2 , 25 mm 2 , 10 mm 2 or 5 mm 2has, and / or c) that the resistor (1) has a certain thickness (D) perpendicular to the plane of the plate and a certain minimum length (L) in the plane of the plate, wherein the ratio between the thickness (D) and the minimum length (L) is at most 1, / z or 74, and / or d) that the conductor material is copper, a copper alloy, aluminium or an aluminium alloy, and / or e) that the conductor material has a lower specific electrical resistance (1) than the resistive material, and / or f) that the conductor material has a specific electrical resistance (1) that is less than 0.5 mm 2 / m, 0.2 mm 2 / m, 0.1 -mm 2 / m, 0.05 mm 2 / m or 0.03 mm 2 / m, and / or g) that the upper terminal part (4), the resistive element (3) and the lower terminal part (5) are each flat, and / or h) that the resistive material is a resistive alloy, in particular hl) a copper-manganese alloy, in particular a copper-manganese-nickel alloy or a copper-manganese-aluminum alloy or a copper-manganese-tin alloy, or h2) a nickel-chromium alloy, in particular a nickel-chromium-aluminum-silicon alloy, or h3) a copper-nickel alloy, or h4) a copper-silver alloy, or h5) a nickel-copper alloy, or h6) a nickel-iron alloy, and / or i) that the resistor (1) is rectangular in plan view, and / or j) that the resistor (1) is an SMD resistor (1), and / or k) that the solder mask is textureable, in particular photo-structurable, in particular as kl) liquid photoimageable solder mask or k2) dry-film photoimageable solder mask,and / or l) that the upper terminal part (4) and / or the lower terminal part (5) has a specific conductor thickness L perpendicular to the plane of the plate, while the upper terminal part (4) and / or the lower terminal part (5) has a specific cross-sectional area A in the plane of the plate, wherein the following ratio applies: L / ^A < 1, Yz or Vs, and / or m) that the upper lacquer frame (10) and / or the lower lacquer frame have substantially the same layer thickness perpendicular to the plane of the plate, and / or n) that the upper lacquer frame (10) and / or the lower lacquer frame have a layer thickness of less than 2 mm, 1 mm, 500 pm, 250 pm, 100 pm or 50 pm perpendicular to the plane of the plate, and / or o) that the upper lacquer frame (10) and / or the lower lacquer frame (11) is applied directly to the plate-shaped resistive element (3) without an intermediate layer, and / or, r) that the solder resist has a lower wettability with respect to the liquid solder than the conductor material of the upper terminal part (4) and the lower terminal part (5).

6. Manufacturing utility (13) with multiple non-isolated resistors (1) according to one of the preceding claims, in particular with more than 10, 50, 100, 500, 1000, 5000 or 10000 non-isolated resistors (1) according to one of the preceding claims.

7. Printed circuit board arrangement comprising a) a printed circuit board (8) and b) a resistor (1) according to any one of claims 1 to 5, wherein the resistor (1) is connected to the printed circuit board (8) by a solder connection (9).

8. Printed circuit board arrangement according to claim 7, characterized in that a) the resistor (1) is arranged on the top side of the printed circuit board (8), b) the solder joint (9) between the resistor (1) and the printed circuit board (8) contacts the entire surface of the lower terminal part (5) of the resistor (1) on its underside, and c) the solder joint (9) is perpendicular to the plane of the printed circuit board (8) and preferably has a layer thickness of at most 1 mm, 500 pm, 200 pm, 100 pm, 50 pm, 20 pm or 10 pm.

9. Manufacturing method for a resistor (1), in particular for a low-resistance current-sensing resistor (1), in particular for a resistor (1) according to one of claims 1 to 10. 5, comprising the following steps: a) providing a plate-shaped resistive element (3) made of a resistive material, in particular as a rigid plate or as a flexible film, b) applying at least one plate-shaped upper terminal part made of a conductor material to the top of the resistive element (3) such that the resistive element (3) is connected to the at least one upper terminal part (4) via at least one upper contact surface (6), and c) applying at least one plate-shaped lower terminal part (5) made of a conductor material to the underside of the resistive element (3) such that the resistive element (3) is connected to the at least one lower terminal part (5) via at least one lower contact surface (7), characterized by the following steps: d) Applying an upper lacquer frame (10) made of an electrically insulating solder mask to the top of the resistor element (3) so that the upper lacquer frame (10) frames the upper terminal part (4) and thereby increases the area of ​​the upper contact surface (6) determined, and / or e) applying a lower lacquer frame (11) made of an electrically insulating solder mask to the underside of the resistive element (3) such that the lower lacquer frame (11) frames the lower terminal part (5) and thereby increases the area of ​​the lower contact surface (7) determined.

10. Manufacturing method according to claim 9, characterized in that a) the upper lacquer frame (10) is applied to the top of the resistance element (3) before the upper connection part (4) is applied to the top of the resistance element (3), and / or b) the lower lacquer frame (11) is applied to the underside of the resistance element (3) before the lower connection part (5) is applied to the underside of the resistance element (3).

11. Manufacturing method according to claim 9 or 10, characterized by the following steps: a) measuring the thickness of the plate-shaped resistance element (3), b) calculating a target value for the area of ​​the upper contact surface (6) and / or the lower contact surface (7) as a function of b1) the measured thickness of the plate-shaped resistance element (3) and b2) the desired resistance value of the resistor (1), and c) adjusting the area of ​​the upper contact surface (6) and / or the lower contact surface (7) according to the calculated target value to compensate for component variations in the thickness of the plate-shaped resistance element (3).

12. Manufacturing method according to claim 11, characterized by a direct measurement of the thickness of the plate-shaped resistive element (3) or alternatively the following steps for the indirect measurement of the thickness of the plate-shaped resistive element (3): a) measuring the electrical surface resistance of the plate-shaped resistive element (3), and b) calculating the thickness of the plate-shaped resistive element (3) as a function of b) the measured electrical surface resistance of the plate-shaped resistive element (3) and b) the measured electrical surface resistance of the plate-shaped resistive element (3). b2) the specific electrical resistance (1) of the resistive material of the plate-shaped resistive element (3).

13. Manufacturing method according to claim 11 or 12, characterized in that a) the area size of the upper contact surface (6) of the plate-shaped resistance element (3) is adjusted by adjusting the inner size of the upper paint frame (10), and / or b) the area size of the lower contact surface (7) of the plate-shaped resistance element (3) is adjusted by adjusting the inner size of the lower paint frame (11).

14. Manufacturing method according to one of claims 11 to 13, characterized by the following steps: a) manufacturing a production panel (13) with several non-separated resistors (1), b) applying the upper lacquer frames (10) and / or the lower lacquer frames (11) of the individual resistors to the production panel (13) before singulating the resistors, and c) singulating the resistors from the production panel (13) after applying the upper lacquer frames (10) and / or the lower lacquer frames (11).

15. Manufacturing method according to one of claims 11 to 14, characterized in that a) the upper lacquer frame (10) and / or the lower lacquer frame (11) is applied photolithographically to the resistance element (3), and / or b) the upper lacquer frame (10) and / or the lower lacquer frame (11) is applied to the resistance element (3) with high precision and a positional tolerance of at most 100 pm, 50 pm, 25 pm, 10 pm or 5 pm in order to precisely match the resistance value of the resistor (1).

16. Manufacturing method according to one of claims 11 to 15, characterized in that, for adjusting the resistance value of the resistor (1), only the area of ​​the upper contact surface (6) and / or the lower contact surface (7) is adjusted, whereas the resistance element (3) is not processed during the adjustment.

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