DE102017206099A1 - Printed circuit board assembly and method for producing a printed circuit board assembly - Google Patents

Abstract

An electronic circuit board assembly (100) will be described. The printed circuit board assembly (100) includes a first circuit board (110) having one or more electrically conductive first contact pads (111) on a front side (114) of the first circuit board (110). In addition, the circuit board assembly (100) includes a second circuit board (120) having one or more electrically conductive second contact pads (121) on a back side (123) of the second circuit board (120). The printed circuit board assembly (100) further includes a spacer (130) having one or more tracks (134) on a back side of the spacer (130) and one or more tracks (134) on a front side of the spacer (130). The one or more printed conductors (134) of the rear side are electrically conductively connected to the one or more printed conductors (134) of the front side. Furthermore, the one or more traces (134) of the back are soldered to the one or more first pads (111). In addition, the one or more conductive traces (134) of the front side are soldered to the one or more second contact pads (121).

Description

The invention relates to a printed circuit board assembly having a plurality of printed circuit boards, which are electrically conductively connected to each other. Furthermore, the invention relates to a method for producing a printed circuit board assembly.

The electronics of an electrical device, in particular a domestic appliance or a household appliance, may be implemented on a plurality of different printed circuit boards, wherein the printed circuit boards are electrically conductively connected to each other. For example, a first circuit board, e.g. a base circuit board having a relatively low number (e.g., 2) of conductor layers (e.g., copper layers). The first circuit board can be used to provide a basic function. Furthermore, a second circuit board, e.g. a module circuit board having a relatively high number (e.g., 4 or more) of conductor layers. In addition, the second circuit board may be of higher and / or higher quality circuit board technology (e.g., HDI circuit board technology) than the first circuit board. The second circuit board may be used to provide an expansion function. Possibly. For example, the second circuit board may be used in different types of electrical devices.

Different circuit boards can be used to provide different functions in each cost and space optimal manner. The different printed circuit boards can be interconnected via board-to-board (B2B) connectors. Two different printed circuit boards are typically manufactured and tested separately. The circuit boards can then be connected to each other during assembly by hand or by machine, in particular plugged. Furthermore, a mechanical fixation is typically used (e.g., a support frame or a screw) to permanently and securely connect the various circuit boards.

The use of connectors and mechanical fixings is typically costly and labor intensive. The present document deals with the technical task of efficiently and mechanically interconnecting different printed circuit boards.

The object is solved by the subject matter of the independent patent claims. Advantageous embodiments are defined in particular in the dependent claims, described in the following description or illustrated in the accompanying drawings.

In accordance with one aspect of the invention, a printed circuit board assembly for an electronic circuit is described. The electronic circuit can be used in an electrical device, e.g. in a domestic appliance or in a household appliance, are used. The printed circuit board assembly includes a first circuit board having one or more electrically conductive first contact pads on a front side of the first circuit board. The first printed circuit board is typically populated with one or more electronic components (e.g., at least one electrical resistor, at least one capacitor, at least one coil, at least one integrated circuit (IC) component, etc.). In this case, the front side and possibly also the rear side of the first printed circuit board can each be equipped with one or more electronic components.

In addition, the printed circuit board assembly comprises a second printed circuit board with one or more electrically conductive second contact points on a back side of the second printed circuit board. The second circuit board is typically populated with one or more electronic components (e.g., at least one electrical resistor, at least one capacitor, at least one coil, at least one IC device, etc.). In this case, the rear side and possibly also the front side of the second printed circuit board can each be equipped with one or more electronic components.

Typically, the first circuit board is larger than the second circuit board. By way of example, the second printed circuit board may have an area that is smaller than the area of the first printed circuit board by a specific factor. The factor may e.g. Be 1.5, 2, 3 or more.

The first circuit board and the second circuit board each typically include one or more conductor layers (e.g., copper) that may be used to provide traces between the one or more components of the respective circuit board. In this case, at least one conductor layer may be located on the front side of the first printed circuit board and a conductor layer on the rear side of the second printed circuit board. In addition, the first conductor layer typically also has a conductor layer on the rear side and the second conductor layer has a conductor layer on the front side. In addition, the first circuit board and the second circuit board may comprise one or more conductor layers, which are each arranged as an intermediate layer between the front side and the back side of the respective circuit board. Overall, the second circuit board may have a higher number of conductor layers than the first circuit board.

The printed circuit board assembly further comprises at least one spacer with or a plurality of tracks on the back of the spacer and with one or more tracks on the front of the spacer. In this case, the one or more conductor tracks of the rear side are electrically conductively connected to the one or more conductor tracks of the front side. The spacer element thus has conductor tracks, which electrically connect the rear side of the spacer element to the front side of the spacer element. The spacer element can be designed as a coherent component. In particular, the front side and the rear side of the spacer element can be firmly and / or inseparably or not detachably connected to one another. For example, the spacer may be formed as a plate having one or more tracks on the front and one or more tracks on the back. It can thus be used a cost-efficient and mechanically stable spacer.

The one or more traces of the backside of the spacer are soldered to the one or more first pads (e.g., solder pads) on the front side of the first circuit board. In addition, the one or more tracks of the front side of the spacer are soldered to the one or more second pads (e.g., solder pads) of the back side of the second circuit board. Thus, a printed circuit board assembly of at least two printed circuit boards can be provided which are connected together in a cost-effective and mechanically stable manner.

The spacer may include one or more vias. The vias connect the front and the back of the spacer. In particular, the one or more interconnects of the rear side of the spacer element can be electrically conductively connected to the one or more interconnects of the front side of the spacer element via the one or more plated-through holes. The one or more vias can be permanently installed and / or inseparable or not be solvable. For example, the one or more plated-through holes can be formed by bores in the spacer element. Alternatively or additionally, the one or more plated-through holes can extend on at least one edge of the spacer element. It can thus be made possible a cost-effective contacting of the tracks on the front with the tracks on the back of the spacer.

The spacer may comprise a spacer printed circuit board or the spacer may be formed as a spacer printed circuit board. The circuit board may be made of a circuit board material (e.g., a fiber reinforced plastic). Furthermore, the spacer printed circuit board may include a first conductor layer for the one or more traces of the rear of the spacer. Furthermore, the spacer printed circuit board may comprise a second conductor layer for the one or more tracks of the front of the spacer. The printed conductors can thereby be replaced by a typical printed circuit board manufacturing process, such as e.g. be created by an etching process. This enables the provision of a cost-effective spacer element.

The spacer element preferably has a height that makes it possible, in a gap between the back of the second circuit board and the front of the first circuit board, one or more electronic components at least on the back of the second circuit board, in particular both on the back of the second circuit board and on the front of the first circuit board, to place. Thus, a particularly cost-effective printed circuit board assembly is provided.

The spacer element may be formed as a cuboid. Furthermore, the spacer may have a certain height, by which the distance between the first circuit board and the second circuit board is defined. Furthermore, the spacer element may have a certain width and a certain length, wherein the width and the length of the spacer element form a base surface with which the spacer element contacts the front side of the first printed circuit board.

The spacer element can be arranged on an edge of the second printed circuit board. In this case, the spacer can at least partially overlap with the second circuit board. That is, a part of the base of the spacer may be disposed below the second circuit board, and contact the back side of the second circuit board. Furthermore, the spacer element may protrude at least partially beyond the edge of the second printed circuit board. For example, the spacer may overlap with 50% or more and / or 10% or more with the second circuit board. Furthermore, the spacer may project 50% or less and / or 10% or more beyond the edge of the second circuit board. Thus, an efficient automatic optical inspection of the solder joints in the manufacture of the printed circuit board assembly is made possible.

Typically, the circuit board assembly has at least two spacers on at least two different (e.g., opposing) edges of the second circuit board. This enables a particularly stable fixation of the printed circuit boards.

In another aspect, an electronic circuit is described that includes the printed circuit board assembly described in this document.

According to a further aspect, an electrical device, in particular a domestic appliance or a household appliance, is described which comprises the printed circuit board arrangement described in this document.

In another aspect, a method of making a printed circuit board assembly for an electronic circuit is described. The method includes creating one or more solder joints between one or more tracks on a front side of a spacer having one or more electrically conductive second contact pads (e.g., solder pads) on a back side of a second circuit board. It can thus be made a sub-assembly in which the spacer is fixed electrically conductive and mechanically stable on the second circuit board.

In addition, the method includes creating one or more solder joints between one or more tracks on a back side of the spacer with one or more electrically conductive first pads on a front side of a first circuit board. In particular, the subassembly can be fixed by means of soldered connections to the first printed circuit board in an electrically conductive and mechanically stable manner.

The one or more interconnects of the rear side of the spacer element are electrically conductively connected to the one or more interconnects of the front side of the spacer element. It can thus be provided in an efficient manner, a printed circuit board assembly in which two circuit boards are connected via one or more electrically conductive connections of a spacer both electrically conductive and mechanically stable.

The one or more solder joints can be created as part of an automatic assembly, in particular a SMT, Surface Mounted Technology, assembly. In this case, the spacer element can be treated like an electronic component in the automatic assembly of the second printed circuit board. Alternatively or additionally, the subassembly of the second printed circuit board and the soldered spacer can be treated like an electronic component in the automatic assembly of the first printed circuit board. In particular, the spacer element and / or the subassembly can be fed to a placement machine for the automatic assembly of the second printed circuit board and / or the first printed circuit board in a tray or on a belt, in particular a blister strip. Thus, the production of a printed circuit board arrangement is made possible in a particularly efficient manner.

The method may include performing an automatic optical inspection of the one or more solder joints. Thus, the reliability of a circuit board assembly can be increased efficiently.

It should be understood that any aspects of the printed circuit board assembly described herein or the method described herein may be combined in a variety of ways. In particular, the features of the claims can be combined in a variety of ways.

• 1 eine beispielhafte Leiterplatten-Anordnung mit zwei Leiterplatten;
• 2 eine beispielhafte Leiterplatte mit einem Abstandselement;
• 3 ein beispielhaftes Abstandselement; und
• 4 ein Ablaufdiagramm eines beispielhaften Verfahrens zur Verbindung von Leiterplatten.

Furthermore, the invention will be described with reference to embodiments illustrated in the accompanying drawings. Show

• 1 an exemplary circuit board assembly with two circuit boards;
• 2 an exemplary circuit board with a spacer element;
• 3 an exemplary spacer; and
• 4 a flowchart of an exemplary method for connecting printed circuit boards.

As stated above, the present document is concerned with the efficient connection of multiple printed circuit boards to produce a printed circuit board assembly. 1 shows a printed circuit board assembly 100 with a first circuit board 110 and a second circuit board 120 , The circuit boards 110 . 120 can each have one or more electronic components 101 have, wherein the components 101 on the front side 114 . 124 and / or on the back 113 . 123 the respective circuit board 110 . 120 can be arranged. The first circuit board 110 For example, it may be a relatively large and a relatively inexpensive circuit board having a relatively low number of conductor layers (eg, two conductor layers on the two surfaces of the circuit board 110 ). On the other hand, the second circuit board 120 relatively small and relatively expensive. For example, the second circuit board 120 one or more additional conductor layers inside the circuit board 120 exhibit. The second circuit board 120 can be used to implement highly integrated switching devices.

The use of different circuit boards 110 . 120 can eg by requirements of certain components 101 to certain printed circuit board technologies, for example multilayer Circuit boards, conditional. A complete implementation on a costly printed circuit board technology is typically associated with relatively high costs. Furthermore, mechanical and / or design-related conditions may require a certain geometry or size of the electronics of an electrical device. It can also be achieved by using different printed circuit boards 110 . 120 realize a modular concept, as so parts of the electronics of an electrical device (eg the on the second circuit board 120 Implemented part) can be used for several different types of electrical equipment.

As in 1 shown, is the second circuit board 120 on the first circuit board 110 assembled. It consists between the first circuit board 110 and the second circuit board 120 prefers a certain gap 103 that makes it possible the back 123 the second circuit board 120 and possibly the front of the first circuit board 110 with one or more components 101 to equip. So can the cost and the area of the circuit board assembly 100 be reduced.

The first circuit board 110 and the second circuit board 120 are about two spacers 130 (also referred to in this document as spacers) connected to each other. This is a spacer 130 with the back 123 the second circuit board electrically conductive and mechanically connected, in particular soldered. Furthermore, a spacer 130 with the front 114 the first circuit board 110 electrically conductive and mechanically connected, in particular soldered.

3 shows details of a spacer 130 , The spacer 130 comprises a printed circuit board, referred to in this document as a spacer printed circuit board. The spacer printed circuit board has a certain thickness, wherein the thickness of the spacer printed circuit board is preferably so large that the gap 103 between the first circuit board 110 and the second circuit board 120 the inclusion of components 101 on the back side 123 the second circuit board 120 allows.

The spacer circuit board has a first conductor layer 131 on (see 2 ), in the installed state of the first circuit board 110 facing and which can be used to the first circuit board 110 electrically conductive contact. Furthermore, the spacer printed circuit board has a second conductor layer 132 on (see 3 ), in the installed state of the second circuit board 120 facing and which can be used to the second circuit board 120 electrically conductive contact.

The first conductor layer 131 and the second conductor layer 132 can each be in one or more tracks 134 segmented or divided to one or more electrically conductive connections between the first circuit board 110 on the one hand and the second circuit board 120 on the other hand. The individual tracks 134 the first conductor layer 131 and the second conductor layer 132 can via vias 135 each, ie in pairs, be electrically connected to each other.

In a first step, one or more spacers can be used 130 at the back 123 the second circuit board 120 be fixed (eg two spacers 130 at two different edges of the second circuit board 120 ). This is exemplary in 2 shown. The one or more tracks 134 the second conductor layer 132 can for this purpose with contact points (especially with solder joints) 122 on the back 123 the second circuit board 120 electrically connected, in particular soldered, are. By making solder joints between the second circuit board 120 and the second conductor layer 132 of the spacer 130 will also be a mechanical fixation between the second circuit board 120 and the spacer 130 reached.

In a second step, the subassembly of the second circuit board 120 and one or more spacers 130 on the front side 114 the first circuit board 110 be attached. In particular, the one or more tracks 134 the first conductor layer 131 the one or more spacers 130 with contact points (especially with solder joints) 112 on the front 114 the first circuit board 110 electrically connected, in particular soldered, are. By making solder joints between the first board 110 and the first conductor layer 131 the one or more spacers 130 will also be a mechanical fixation between the first circuit board 110 and the one or more spacers 130 reached. In total, an electrically conductive and mechanically fixing connection between the first printed circuit board 110 and the second circuit board 120 causes.

A spacer 130 can, as in 1 illustrated, be arranged such that the spacer 130 an overlapping area with the second circuit board 120 and a non-overlapping area with the second circuit board 120 having. Thus, an efficient inspection of the connection, in particular the solder joints, between the spacer 130 and the respective circuit board 110 . 120 respectively. In particular, after the first production step (see 2 ), a check (eg, an optical check) of the joints between the second conductor layer 132 of the spacer 130 and the second circuit board 120 respectively. After the second production step can then be a review of the connection points between the first conductor layer 131 of the spacer 130 and the first circuit board 110 respectively.

The two or more circuit boards 110 . 120 are therefore not plugged together, but soldered together. This will be one or more spacers 130 used, which is between each two circuit boards 110 . 120 be soldered.

The spacers 130 are made of printed circuit board material and preferably have a height, so that components 101 between the circuit boards 110 . 120 can be installed. The one or more spacers 130 be in the placement of the bottom or back 123 the second (smaller) circuit board 120 equipped with. The equipment can be done automatically. In particular, a spacer 130 "strapped" as a component or placed in a tray to the second circuit board 120 with the spacer 130 to equip. It thus becomes an efficient manufacturing process of the subassembly of the second circuit board 120 and the one or more spacers 130 allows.

On the one or more spacers 130 In each case, a two-layered copper layout may be provided, which solder pads on the top of a spacer 130 with solder pads 121 on the bottom of the second circuit board 120 (in a 1: 1 relationship), and / or which solder pads on the bottom of a spacer 130 with solder pads 111 on the front of the first circuit board 110 (in a 1: 1 relationship) connects

The second circuit board 120 with one or more equipped spacers 130 can before mounting on the first circuit board 110 be tested separately. This can be an automatic optical inspection (AOI) of the solder joints of one or more spacers 130 be performed.

The subassembly of the second circuit board 120 and the one or more spacers 130 can in another process like an electronic component 101 handled on the front 114 the first circuit board 110 to place. The subassembly can be strapped or placed in a tray and thus fed to another SMT process, in which the subassembly with solder pads 111 the first circuit board 110 soldered and thus with the first circuit board 110 is joined together.

The solder joints hiss the spacer 130 and the front 114 the first circuit board 110 can also be checked by AOI as the spacers 130 over the edge of the second circuit board 120 (For example, about 1/3 of the base of the spacer 130 ) protrude.

4 shows a flowchart of an exemplary method 400 for producing a printed circuit board assembly 100 for an electronic circuit. The procedure 400 includes creating 401 of one or more solder joints between one or more tracks 134 on the front of a spacer 130 with one or more electrically conductive second contact points 121 on the back side 123 a second circuit board 120 , It can thus in a first step, a subassembly of a second circuit board 120 and at least one spacer element 130 be formed. Typically, at least two spacers 130 at different edges of the second circuit board 120 fixed by soldering.

In addition, the process includes 400 creating 402 of one or more solder joints between one or more tracks 134 on the back of the at least one spacer element 130 with one or more electrically conductive first contact points 111 on the front side 124 a first circuit board 120 , In a second step, thus, the sub-assembly of the second circuit board 120 and the one or more spacers 130 on the first circuit board 110 be soldered.

By soldering second circuit boards 110 . 120 over a spacer element 130 , In particular via a spacer circuit board, can be dispensed with an additional mechanical fixation. The circuit boards 110 . 120 can be fully automatically loaded in an SMT process and connected to each other. Furthermore, both circuit boards 110 . 120 be equipped on both sides. It is also possible in the overlapping area 103 between the two circuit boards 110 . 120 components 101 be installed. In particular, no recess in the first circuit board 110 for components 101 on the back side 123 the second circuit board 120 needed. This will increase the stability of the printed circuit board assembly 100 elevated. In addition, so closed copper (screen) surfaces can be made possible. Furthermore, the available area on the first circuit board 110 be used for the provision of printed conductors.

By soldering a solid mechanical connection is created. Quality problems due to loose or detachable plug connections can be ruled out. It also eliminates the cost of a connector, mechanical fixation and assembly.

The spacers described in this document 130 can be made in standard processes by an electronics manufacturer. In particular, the required interconnects 134 on the spacer 130 be manufactured by standard processes for the production of a printed circuit board.

The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and the figures only the principle of the printed circuit board assembly described 100 and the method described 400 should illustrate.

Claims (10)

Printed circuit board arrangement (100) for an electronic circuit, wherein the printed circuit board arrangement (100) comprises - A first circuit board (110) having one or more electrically conductive first contact points (111) on a front side (114) of the first circuit board (110); - A second printed circuit board (120) having one or more electrically conductive second contact points (121) on a back side (123) of the second printed circuit board (120); - A spacer element (130) having one or more tracks (134) on a rear side of the spacer element (130) and with one or more tracks (134) on a front side of the spacer element (130); wherein the one or more conductive traces (134) of the back side are electrically connected to the one or more conductive traces (134) of the front surface; wherein the one or more backside traces (134) are soldered to the one or more first contact pads (111); and wherein the one or more conductive tracks (134) of the front side are soldered to the one or more second contact pads (121). Printed circuit board assembly (100) according to Claim 1 wherein - the spacer element (130) comprises one or more vias (135); and - the one or more tracks (134) of the rear of the spacer (130) are electrically connected to the one or more vias (134) of the front of the spacer (130) via the one or more vias (135). Circuit board arrangement (100) according to one of the preceding claims, wherein - The spacer (130) comprises a spacer circuit board; - The spacer board comprises a first conductor layer (131) for the one or more tracks (134) of the back of the spacer (130); and - The spacer circuit board comprises a second conductor layer (132) for the one or more tracks (134) of the front of the spacer (130). A printed circuit board assembly (100) according to any one of the preceding claims, wherein the spacer (130) has a height enabling it to be interposed in a gap (103) between the back side of the second circuit board (120) and the front side of the first circuit board (120). one or more electronic components (101) at least on the back of the second circuit board (120), in particular both on the back of the second circuit board (120) and on the front side of the first circuit board (110) to place. Circuit board arrangement (100) according to one of the preceding claims, wherein the spacing element (130) - Is arranged on an edge of the second circuit board (120); and - At least partially beyond the edge of the second circuit board (120) protrudes. A printed circuit board assembly (100) according to any one of the preceding claims, wherein the circuit board assembly (100) comprises at least two spacers (130) on at least two different edges of the second circuit board (120). A method (400) of making an electronic circuit board assembly (100), the method comprising (400) - creating (401) one or more solder joints between one or more tracks (134) on a front side of a spacer (130) having one or more electrically conductive second pads (121) on a back side (123) of a second circuit board (120); and - creating (402) one or more solder joints between one or more tracks (134) on a back side of the spacer (130) having one or more electrically conductive first pads (111) on a front face (124) of a first board (120); wherein the one or more interconnects (134) of the rear side of the spacer element (130) are electrically conductively connected to the one or more interconnects (134) of the front side of the spacer element (130). Method (400) according to Claim 7 in which - the one or more solder joints are produced as part of an automatic assembly, in particular an SMT, surface mounted technology, assembly; - The spacer (130) as an electronic component (101) in the automatic assembly of the second circuit board (120) is treated; and - a subassembly of the second circuit board and the soldered spacer element (130) as an electronic component (101) in the automatic Equipment of the first circuit board (110) is treated. Method (400) according to Claim 8 wherein the spacer element (130) and / or the subassembly is fed to a placement machine for automatic placement in a tray or on a belt. Method (400) according to one of Claims 7 to 9 wherein the method (400) comprises performing an automatic optical inspection of the one or more solder joints.

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