METHOD FOR PROTECTING THE COMPONENTS OF A PRINTED CIRCUIT BOARD

Abstract

A method for protecting the components of a printed circuit board which is loaded with specified components includes setting up a coating barrier in the form of an edge around coating exclusion regions of a printed circuit board into which a protective coating does not penetrate, and providing the printed circuit board with the protective coating at specified regions thereof. A printed circuit board produced by the method is also disclosed.

Claims

1. A method for protecting components of a printed circuit board, the method comprising: setting up a coating barrier in the form of an edge around coating exclusion regions of the printed circuit board, into which a protective coating does not penetrate; and providing the printed circuit board with the protective coating at specified regions thereof.

2. The method according to claim 1, further comprising: producing the coating barrier by taking back a solder resist coating and/or taking back a copper layer of the printed circuit board.

3. The method according to claim 1, further comprising: producing the coating barrier on an upper side and/or an underside of the printed circuit board.

4. The method according to claim 2, further comprising: producing the coating barrier on an upper side and/or an underside of the printed circuit board.

5. The method according to claim 1, wherein the coating exclusion regions are specified regions around at least one of electronic components, connectors, pins, screwing areas, through-openings, and/or production bearing surfaces.

6. The method according to claim 2, wherein the coating exclusion regions are specified regions around at least one of electronic components, connectors, pins, screwing areas, through-openings, and/or production bearing surfaces.

7. The method according to claim 3, wherein the coating exclusion regions are specified regions around at least one of electronic components, connectors, pins, screwing areas, through-openings, and/or production bearing surfaces.

8. A printed circuit board, comprising: a plurality of components; and a protective coating at specified regions of the printed circuit board, wherein the printed circuit board is produced by a method comprising: setting up a coating barrier in the form of an edge around coating exclusion regions of the printed circuit board, into which the protective coating does not penetrate; and providing the printed circuit board with the protective coating at the specified regions thereof.

9. The printed circuit board according to claim 8, wherein the printed circuit board is produced by the method further comprising: producing the coating barrier by taking back a solder resist coating and/or taking back a copper layer of the printed circuit board.

10. The printed circuit board according to claim 8, wherein the printed circuit board is produced by the method further comprising: producing the coating barrier on an upper side and/or an underside of the printed circuit board.

11. The printed circuit board according to claim 8, wherein the coating exclusion regions are specified regions around at least one of electronic components, connectors, pins, screwing areas, through-openings, and/or production bearing surfaces.

12. An inverter comprising the printed circuit board according to claim 8.

13. An electronics module for controlling an electric drive of a vehicle, wherein the electronics module comprises the inverter according to claim 12.

14. An electric drive of a vehicle comprising the electronics module according to claim 13.

15. A vehicle comprising the electric drive according to claim 14.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 shows a schematic view of a component arranged on a printed circuit board and having a coating layer according to the prior art.

[0017] FIGS. 2, 3, and 4 each show a schematic view of components surrounded by a coating barrier according to different embodiments of the present invention.

[0018] FIG. 5 shows a flow diagram of a method according to another embodiment of the present invention.

DETAILED DESCRIPTION

[0019] In the following descriptions of the figures, the same elements or functions are provided with the same designations.

[0020] As already mentioned above, due to the coating tolerance or the characteristics of the protective coating 2, it may flow into coating exclusion regions 30, as shown in FIG. 1, and consequently lead to components being damaged, with the result that the printed circuit board 1 can no longer be used.

[0021] In order to avoid this, a coating barrier 31 is produced before the coating of the printed circuit board 1, to be precise before specific regions (coating exclusion regions 30) thereof. This protects the coating exclusion regions 30, and consequently the components 10-12 to be protected, from uncontrolled inflow or penetration of the protective coating 2. In this way the protective coating 2 is prevented from flowing into regions (coating exclusion regions 30) that are not intended to be covered by the protective coating 2 on account of its viscosity.

[0022] Such coating exclusion regions 30 are for example specified regions around electronic components 10 such as microcontrollers or sensors, connectors, pins, screwing areas, through-openings 12, production bearing surfaces 11, etc.

[0023] As shown in FIGS. 2 to 4, the coating barrier 31 is an actual, mechanical barrier in the form of an edge. This serves as a wetting obstacle, at which the protective coating 2 gets held up as a result of cohesive forces or surface tension, that is to say can no longer flow on account of physical conditions. In FIGS. 3 and 4, the protective coating 2 applied to the solder resist coating 3 is indicated in the drawing. In FIG. 2, a protective coating 2 has not yet been applied, only the coating barrier 31 has been created.

[0024] Providing the edge as a coating barrier 31 is advantageous not only because damage due to shorting or clogging of openings etc. as a result of the inflow of the protective coating 2 to the components 10-12 that are actually to be protected from this can be prevented. What is more, the transitional region between the coating region (region to be coated of the printed circuit board 1) and the coating exclusion region 30 can also be reduced, and consequently a higher packing density can be achieved.

[0025] The edge of the coating barrier 31 is produced by the solder resist coating 3 that is present on the printed circuit board 1 and/or the copper layer of the printed circuit board 1 that is either exposed or lies under the solder resist coating 3 being taken back to a specified distance, i.e. removed by corresponding methods such as etching. In FIG. 2, only the solder resist coating 3 has been removed, whereas in FIGS. 3 and 4 the copper layer has likewise been removed.

[0026] The distance of the edge from the component 10-12 to be protected from penetration of the protective coating 2 is dependent at least on the type of protective coating 2 to be applied, the coating method, the component 10-12 to be protected, the materials used, etc., while if need be further criteria, to be defined, may also be used. Providing the edge allows the distance of the coating exclusion region 30 from the component 10-12 to be reduced in size, with the result that structural elements that are arranged alongside the component and are to be covered by the protective coating 2 can be arranged closer to the component 10-12. The edge also makes it possible for structural elements that are arranged close to the component 10-12 to be covered with the protective coating 2 in the first place. This was sometimes not possible with the previous methods, or was inadvisable because the risk of the protective coating 2 penetrating into the coating exclusion region 30 of the component 10-12 and causing damage there was too high.

[0027] Depending on the component loading of the printed circuit board 1, the solder resist coating 3 and/or copper layer on the upper side and/or underside of the printed circuit board 1 may be removed.

[0028] Shown in FIG. 5 is a flow diagram of the method according to one embodiment of the present invention in which, in a preliminary step or initial step SO, a coating barrier 31 is set up around coating barrier regions 30, into which the protective coating 2 to be applied in the subsequent step 51 must not penetrate, in the form of an edge which is produced by taking back the solder resist coating 3 and/or taking back the copper layer of the printed circuit board 1.

[0029] To summarize, this means that the present invention has at least the following advantages. A reduction of the residual contamination requirements for all further components and also for production processes is possible. This brings about a massive cost saving. Using a standard SMD soldering process or other standard types of fastening means that no further requirements have to be met to obtain approval. The described method also allows the number of rejects in production to be minimized.

[0030] The proposed method and the printed circuit board 1 produced by it are advantageously used in the case of inverters in the area of electromobility, that is to say for controlling an electric drive or some other electric machine, but also other applications in which components of the printed circuit board 1 must be protected from being penetrated by protective coating 2.

Reference Numbers

[0031] 1 Printed circuit board

[0032] 2 Protective coating

[0033] 3 Solder resist coating

[0034] 10 Component (electrical component)

[0035] 11 Component (through-openings)

[0036] 12 Component (production bearing surface)

[0037] 30 Coating exclusion region

[0038] 31 Coating barrier