EP3850924A1

EP3850924A1 - Method for producing a circuit board assembly, and circuit board assembly

Info

Publication number: EP3850924A1
Application number: EP19768755.1A
Authority: EP
Inventors: Rafael DEL REY; Markus BEBENDORF
Original assignee: Continental Automotive GmbH
Current assignee: Continental Automotive Technologies GmbH
Priority date: 2018-09-14
Filing date: 2019-09-10
Publication date: 2021-07-21
Also published as: US20210329793A1; WO2020053160A1; CN112703825A; DE102018215672A1

Abstract

The invention relates to a method for producing a circuit board assembly (3), comprising the steps: providing a first circuit board substrate (1); providing a second circuit board substrate (2), which is arranged substantially plane-parallel to the first circuit board substrate (1), the first circuit board substrate (1) having a bottom side (11) and the second circuit board substrate (2) having a surface (12), the surface (12) and the bottom side (11) being arranged facing one another; providing first connection contacts (14), which are applied to the bottom side (11) of the first circuit board substrate (1); providing second connection contacts, which are applied to the surface (12) of the second circuit board substrate (2); applying solder paste cylinders (7) to the first connection contacts (14), the solder paste cylinders (7) being applied to the first connection contacts (14) by means of a solder paste application method with solder paste, the applied solder paste cylinders (7) each having a solder paste cylinder surface; and arranging the second connection contacts (4) of the second circuit board substrate (2) on the solder paste cylinder surfaces of the solder paste cylinders (7). The invention further relates to a circuit board assembly.

Description

description

Method of manufacturing a circuit board arrangement and circuit board arrangement

The invention relates to a method for producing a printed circuit board arrangement. The invention further relates to a circuit board arrangement.

Nowadays, solder balls are used for the electrically conductive connection of two printed circuit boards. This allows more solder paste to be used per connection than is typically the case with simple solder paste connections. So-called ball grid arrays (BAG) have been developed for the arrangement of the solder balls, which use rows and columns of discretely spaced solder balls in order to produce the necessary electrical connections by melting the solder paste.

There are various methods for placement and subsequent melting to create a conductive connection. This is the so-called laser jetting, for example, in which the solder balls are placed one after the other in each connection provided for this purpose and then pressure-contacted. Furthermore, the solder balls can be arranged on the connection contacts using a positioning system (pick and place system) and connected using SMD technology (surface-mounting technology, SMT). Another application possibility and connection method results from the electroplating of a copper layer, the subsequent etching by photolithography, and the subsequent heating. However, these methods result in a cumbersome, unreliable, and expensive connection solution.

US 20060249303 A1 discloses a connection-free connection from board to board, from cable to board or from cable to Electric wire. The connection has solder beads or semi-ellipsoidal surface structures for connection.

DE 10138042 A1 discloses a method for producing an electronic component which has at least one semiconductor chip and a rewiring plate, on the first side of which the semiconductor chip is mounted, conductor structures and connection contacts for electrical contacting of the contacting being on a second side of the rewiring plate facing away from the semiconductor chip Electronic component with a printed circuit board are provided, with the steps: providing an um wiring board with applied on the second side conductor tracks and connection contacts, mounting a semiconductor chip on the first side of the redistribution board without conductor track structures and making electrical connections between contact connections of the semiconductor chip and the Conductor tracks of the rewiring plate, application of a closed solder stop layer on the second side of the rewiring plate, structuring of the solder stop layer, the connection contacts are at least partially exposed, and an inner circumferential surface of an opening of the solder stop layer surrounding each connection contact, which is widened obliquely and / or in steps, is formed, applying a solder ball to each exposed connection contact, the solder balls each having little play to the edge of the opening of the solder stop layer, Establishing a flip-chip connection between the electronic component and a printed circuit board by placing the electronic component with its solder balls on contact surfaces of the printed circuit board and melting the solder balls.

The invention has for its object to provide an inexpensive and simple solution to the above problem.

This object is achieved by specifying a method for producing a circuit board arrangement with the features of claim 1 and specifying a circuit board arrangement with the features of claim 8. The object is achieved by specifying a method for producing a printed circuit board arrangement with the steps:

Providing a first printed circuit board substrate,

Providing a second printed circuit board substrate which is arranged essentially plane parallel to the first printed circuit board substrate, the first printed circuit board substrate having an underside and the second printed circuit board substrate having a surface, the upper surface and the underside being arranged opposite one another,

Providing first connection contacts, which are applied to the underside of the first printed circuit board substrate,

Providing second connection contacts which are applied to the surface of the second printed circuit board substrate,

Application of solder paste cylinders to the first connection contacts, wherein the application of the solder paste cylinders to the first connection contacts is carried out by a solder paste application method with solder paste, the applied solder paste cylinders each having a solder paste cylinder surface, and

Arranging the second connection contacts of the second printed circuit board substrate on the solder paste cylinder surfaces of the solder paste cylinders.

Printed circuit board substrate is usually to be understood as a printed circuit board (PCB) or a substrate which is provided for forming a printed circuit board.

Solder paste cylinders are to be understood as columns / cylinders, essentially cylindrical in shape, made of solder paste (solder paste). It should be noted that cylinder is only to be understood as the rough shape, with smaller and larger deviations, and not an exact mathematical description. It has been recognized that a connection made by solder balls can be destroyed if a distortion or warp caused by thermal expansion during subsequent melting occurs in the two circuit board substrates by one or more solder balls remaining during melting only with one of the two printed circuit board substrates is in contact.

The invention has the effect that the separation of the connection between the circuit board substrates is avoided. The solder paste cylinders expand flexibly when the two printed circuit board substrates are bulged, for example due to melting, so that almost all connections are preserved during a heating process. Due to the cylindrical shape made of solder paste, a detachment of the connection between the circuit board substrates can be avoided with a high warpage and a large curvature, for example up to 2.5 times the original distance between the two circuit board substrates. Even in the case of a delay in which the distance between the two printed circuit board substrates is less than the original distance between the two printed circuit board substrates, the connection is maintained by the solder paste cylinders being able to be compressed or pressed together flexibly. A burst, as can be the case with metallic solder balls, for example, can be avoided.

Thus, almost all connections, which are formed by the solder paste cylinders, can be retained during heating and subsequent cooling by the invention.

The complex placement of solder balls can also be dispensed with, which leads to lower manufacturing costs.

The manufacture of the circuit board substrates according to the invention also requires no fastening or alignment elements, which results in lower manufacturing costs. The solder paste cylinders according to the invention enable flexible arrangement on the printed circuit board substrates. HDI printed circuit boards (high-density interconnect printed circuit boards) with high contact or connection density, in particular printed circuit boards with more than 500 connections or pins per square decimeter, can thus be formed.

The method preferably comprises the further step: melting the solder paste cylinders to form a mechanical and electrically conductive connection between the first connection contacts of the first printed circuit board substrate and the second connection contacts of the second printed circuit board substrate. This creates a reliable contact between the two circuit board substrates. Due to the melting, a particularly simple connection between the first and second connection contacts is possible.

In a further preferred embodiment, the melting is accomplished by a reflow process or a Schwallot process. Reflow soldering is a technology in which a solder paste that has already been applied to the component to be soldered is liquefied again by heating and the desired contacts are thereby produced. In the known reflow soldering methods, the solder paste is usually printed on the circuit boards or components to be soldered. The reflow process is mainly used for SMD components (surface-mount device).

In the Schwallot process, liquefied solder is already fed to the solder joint, whereby the melting is achieved.

Preferably, at least one distortion point occurs during the melting due to thermal expansion of the first circuit board substrate and / or the second circuit board substrate, so that the solder paste cylinders form a peanut-shaped shape and / or a compact columnar shape at the at least one distortion point. Due to the flexible expansion of the soldering the mechanical and electrical connection is retained.

The solder paste cylinders are furthermore preferably applied to the first connection contacts by means of a solder paste printing process. This makes it easy to apply the solder paste cylinder.

Preferably, when the solder paste cylinders are applied by the solder paste application method, at least one surface-mountable connection surface made of solder paste, in particular for fastening SMD components, is simultaneously applied to a connection pad provided for this purpose and arranged on the underside.

As a result, connections can be made in one work step both for the circuit board arrangement in the form of the solder paste cylinders and for SMD components. For the simultaneous application and simultaneous melting of the solder paste cylinders and the connection surfaces for SMD components, no additional work step is therefore necessary. This saves both manufacturing time and costs.

In a further preferred embodiment, the solder paste cylinders are formed on the first connection contacts through at least one first passage channel in a printing template and the formation of a connection area through at least a second passage channel in the printing template, the printing template having a stepped height profile with a first height and at least a second height has, so that the first passage channel has the first height and the second passage channel has the second height. This makes it particularly easy to apply the solder paste cylinders and connection pads in one step.

Furthermore, the object is achieved by specifying a Lei terplattenanordnung comprehensive

a first circuit board substrate, a second printed circuit board substrate which is arranged substantially plane-parallel to the first printed circuit board substrate, the first printed circuit board substrate having an underside and the second printed circuit board substrate having a surface, the surface and the underside being arranged opposite one another,

first connection contacts, which are applied to the underside of the first circuit board substrate and second to

final contacts, which are applied to the surface of the second printed circuit board substrate,

Solder paste cylinders, which are arranged between the first connection contacts of the first printed circuit board substrate and the corresponding second connection contacts of the second printed circuit board substrate to form a mechanical and electrically conductive connection between the first connection contacts of the first printed circuit board substrate and the second connection contacts of the second printed circuit board substrate, the Solder paste cylinders are applied to the first connection contacts by a solder paste application method with solder paste.

The circuit board arrangement according to the invention has the effect that almost all of the connections which are formed by the solder paste cylinders are retained during heating and subsequent cooling. The advantages of the method can also be transferred to the circuit board arrangement.

In a further preferred embodiment, the solder paste application process is a solder paste printing process. This makes it particularly easy to apply the solder paste.

The solder paste cylinders preferably have a height that extends between the first connection contacts of the first printed circuit board substrate and the second connection contacts of the second printed circuit board substrate, the height having a value in the range from 350 μm to 700 μm. This height is particularly suitable good for making a circuit board assembly that can be used in a vehicle.

The connection is particularly preferably a soldered connection.

The mechanical and electrically conductive connection between the first connection contacts of the first printed circuit board substrate and the second connection contacts of the second printed circuit board substrate is particularly preferably accomplished by melting the solder paste cylinders. This enables a particularly simple connection to be established.

Since the first printed circuit board substrate and / or the second printed circuit board substrate have at least one warping point due to the melting, it is advantageous if the soldering paste cylinders have a peanut-shaped shape and / or a compact columnar shape at the at least one warping point. Advantageously, in the case of a delay in which the first printed circuit board substrate is at a greater distance from the second printed circuit board substrate compared to the original distance, the solder paste cylinders have a peanut-shaped shape, and / or in the case of a delay in which the first printed circuit board substrate has a second printed circuit board substrate, compared to the original distance, has a smaller distance, the solder paste cylinder has a compact columnar shape. This allows the warpage to be compensated for well without breaking the resulting connections.

In a preferred embodiment, the first connection contacts and the solder paste cylinders applied thereon are arranged in a ring on the underside. A ring-shaped pattern can be used to reduce thermal distortion / warping when melting.

The first connection contacts and the soldering paste cylinders preferably form a plurality of ring circumference lines, the soldering paste cylinders of the individual ring circumference lines have a distant distance from each other. In addition, the individual ring circumference lines are also equidistant from one another. Thereby, thermal hot spots can be avoided.

The first printed circuit board substrate particularly preferably has at least one SMD component arranged on the underside and the second printed circuit board substrate has a recess, the at least one SMD component at least partially protruding into the recess. This can save space.

According to an advantageous development, the first printed circuit board substrate is substantially larger than the second printed circuit board substrate. The first circuit board substrate can thus serve as the main circuit board, while the second circuit board substrate serves as a circuit module carrier.

Such a circuit board arrangement is particularly well suited for use in an electronic instrument cluster or another motor vehicle / control / display device, such as a radio etc.

The circuit board arrangement is particularly preferably produced using the method as described above.

Further features, properties and advantages of the present invention will become apparent from the following description with reference to the accompanying figures. The following show:

1 shows a circuit board assembly according to the prior art,

2 shows schematically a second circuit board substrate according to the invention,

3 shows schematically a circuit board arrangement according to the

Invention,

4: a printing stencil and a first circuit board substrate according to the invention, 5 shows a circuit board arrangement with solder paste cylinder in the reflow process according to the invention,

6 shows an arrangement of the solder paste cylinders on the first

Printed circuit board substrate according to the invention.

Although the invention has been illustrated and described in detail by the preferred exemplary embodiment, the invention is not restricted by the disclosed examples. Variations on this can be derived by those skilled in the art without departing from the scope of the invention as defined by the following claims.

1 shows a circuit board assembly 100 in the reflow method according to the prior art. The printed circuit board assembly 100 comprises a first printed circuit board 101 and a second printed circuit board 102 as well as solder balls 103 arranged therebetween for mechanical and electrically conductive connection. The solder balls 103 are preformed metal balls. In the reflow process, the thermal expansion of the printed circuit boards 101, 102 results in warping or warping of the printed circuit boards 101, 102, which here results in an opposite curvature of the two printed circuit boards 101 and 102. The oppositely directed curvature of the two printed circuit boards 101, 102 and the resulting spacing between the two printed circuit boards 101, 102 result in the solder balls 103 adhering to one of the two printed circuit boards 101, 102 and separating the solder balls 103. that some of the connections are broken. The solder balls 103 solidify before they have contact with the two printed circuit boards 101, 102 again.

If the distance between the two printed circuit boards 101, 102 becomes too small during the reflow process, there is a risk that the metal balls preformed as solder balls 103 "explode" if the two printed circuit boards 101, 102 are at a smaller distance apart than a solder ball due to thermal distortion money diameter. 2 shows a second printed circuit board substrate 2 for forming a printed circuit board arrangement 3 (FIG. 3) according to the invention. The second printed circuit board substrate 2 has a surface 12 and second connection contacts 4 arranged thereon and a recess 5. The second connection contacts 4 are arranged in a ring on the surface 12 in an edge region 6 or periphery of the recess 5. It also includes a square rounded or beveled at the corners. A connection contact 4 preferably has a circular surface with a diameter of 450 μm.

3 shows a circuit board arrangement 3 according to the invention. The circuit board arrangement 3 has a first circuit board substrate

1 with an underside 11 and the second circuit board substrate

2 with the surface 12. The first printed circuit board substrate 1 likewise has first connection contacts 14 (FIG. 4), which are arranged on the underside 11. The first connection contacts 14 and second connection contacts 4 (FIG. 2) are arranged corresponding to one another on the underside 11 of the first printed circuit board substrate 1 and the surface 12 of the second printed circuit board substrate 2. The PCB arrangement

3 has 2 solder paste cylinders 7 to form a mechanical and electrically conductive solder connection between the connection contacts 14 (FIG. 4) of the first printed circuit board substrate 1 and the second connection contacts 4 (FIG. 2) of the second printed circuit board substrate 2. The solder connection is made by melting on the solder paste cylinder 7. The first printed circuit board substrate 1 can be designed, for example, as a printed circuit board (PCB).

The solder paste cylinders 7 are applied to the first connection contacts 14 (FIG. 4) by means of the solder paste printing method.

At the same time as the application of the solder paste cylinders 7, connection surfaces 10 (FIG. 4) for connecting other SMD components can also be applied to corresponding connection pads (not shown) of the first printed circuit board substrate 1 and / or other connections. SMD components do not require circuit board holes for their assembly, but are soldered with their connections directly to the connection pads provided for this purpose on the circuit board substrate. SMD components are then mechanically placed on the connection pads provided with soldering paste using, for example, automatic placement machines and soldered together with the soldering paste cylinder 7 in a single reflow process.

Due to the simultaneous application of the solder paste cylinder 7 to form a mechanical and electrically conductive connection between the first connection contacts 14 (FIG. 4) and second connection contacts 4 (FIG. 2) and thus between the first circuit board substrate 1 and the second circuit board substrate 2 and the connection area 10 (FIG 4) in a common work step, the manufacturing costs can be reduced by up to 50%. Faster production can be accomplished. The connection by solder paste cylinder 7 also requires no separate fastening or alignment elements, for example adhesive. This can also save costs.

The solder paste cylinders 7 have a cylindrical column shape before melting, for example in a reflow process. A solder paste cylinder 7 before melting is shown in FIG. 4.

Solder paste or solder paste is usually a paste-like mixture of solder metal powder and flux. There are solder pastes for brazing based on copper / zinc and silver and for resistance soldering. For example, solder paste suitable for SMD soldering consists of approximately 90% tin alloy beads and approximately 10% flux. The percentages relate to the percentages by mass. The solder pastes which can be used in the present invention preferably comprise paste-like printing compositions of any chemical compositions which are preferably used for producing electrically conductive contacts can. However, other suitable solder pastes can also be used.

The SMD components can be arranged on the underside 11 of the circuit board substrate 1 in such a way that when the circuit board substrate 1 is arranged on the second circuit board substrate 2 they at least partially protrude into the recess 5 (FIG. 2).

The solder paste is applied by means of a printing template 8, as shown in FIG. 4. The solder paste is by means of

Stencil pressure applied to the first connection contacts 14 of the first circuit board substrate 1 to form a mechanical and electrically conductive connection between the first connection contacts 14 of the first circuit board substrate 1 and the second connection contacts 4 (FIG. 2) of the second circuit board substrate 2, and also to the connection pads (not shown) preferably to form an electrically conductive and mechanical contact between the SMD components and the circuits applied to the circuit board substrate 1.

The printing template 8 has passage channels 9a, 9b. Furthermore, the printing template 8 has a stepped height profile with at least two different heights h1 and h2, hl being higher than h2. This results in at least one first passage channel 9a with a first height hl and a second

Passage channel 9b of a second height h2, the first height h1 having a greater value than the second height h2.

The solder paste is applied using the printing stencil 8 on the printed circuit board substrate 1 to form a connection surface 10 for SMD components and on the connection contacts 14 to form solder paste cylinders 7. By means of the two different high and wide passage channels 9a, 9b, connections with different geometry, that is, width and height, such as the connection surface 10 for SMD components or else the solder paste cylinders 7 can now be printed. In this In the exemplary embodiment, the solder paste cylinders 7 are printed with the aid of the passage channels 9a, which have the height h1. The passage channels 9a must be positioned centered on the connection contacts 14. The same applies to the connection areas 10.

Subsequently, the SMD components on the connection surface 10 and also the second connection contacts 4 (FIG. 2) together with the second circuit board substrate 2 are positioned on the solder paste cylinder surfaces of the solder paste cylinders 7. The use of solder paste cylinders 7 and connection surfaces 10 made of solder paste has the advantage that the solder paste is sticky and so the SMD components and the second printed circuit board substrate 2 with the second connection contacts 4 (FIG. 2) adhere directly to the solder paste cylinders 7. For example, separate gluing can thus be dispensed with. Subsequently, the circuit board arrangement 3 thus produced is passed through a so-called reflow oven, in which the flux is activated by the heat effect and finally evaporates. The solder paste cylinders 7 melt and connect to the first connection contacts 14 and second connection contacts 4 (FIG. 2) of the respective printed circuit board substrate 1, 2. The same applies to the connection surfaces 10 and the SMD components fitted thereon. The mechanical and electrically conductive connection is formed, which is also referred to as a solder or solder connection.

Alternatively, the solder paste cylinders 7 can also be printed on the second connection contacts 4 (FIG. 2) of the second printed circuit board substrate 2. You can then continue as described above.

In this exemplary embodiment, the printing stencil 8 has a first height h1 of approximately 300 μm for the first passage channel 9a, and a second height h2 of approximately 150 μm for the second passage channel 9b. The passage channels 9a, 9b have a total distance from one another, which is composed of the distances A1 and A2. The first has a distance Al has a width greater than 5.85 μm and the second distance A2 has a width greater than or equal to 0.65 μm. Depending on the height of the solder paste cylinder 7, the height can also be chosen differently. The solder paste cylinders 7 can also have a height of 700 μm.

A well-known solder paste application process is screen or stencil printing. The stencil / screen printing process enables high-precision application of solder paste on printed circuit boards.

4 also shows a solder paste cylinder 7 in the printed state, prior to melting. This has a cylinder height ZH with a value of approximately ZH = 450 μm. The solder paste cylinder 7 preferably has a value between 300 and 700 μm. The solder paste cylinder 7 has a substantially cylindrical shape. FIG. 4 also shows a connection area 10 for connecting SMD components.

The electrically conductive connection produced by the solder paste cylinders 7 allows the printed circuit board substrate 1, 2 to be designed as HDI printed circuit boards

(High-density interconnect circuit board) with high contact or connection density, in particular a circuit board with more than 500 connections or pins per square decimeter.

5 shows a printed circuit board arrangement 3 in the reflow process, with the first printed circuit board substrate 1 and the second printed circuit board substrate 2. The two printed circuit board substrates 1, 2 each have an oppositely directed curvature due to the thermal expansion in the reflow process. By using solder paste cylinder 7 this curvature can be compensated for. The solder paste cylinders 7 can expand and take on the shape of a peanut, for example, if a distance between the circuit board sub strate 1, 2 arises due to the curvature, which is greater than the previous distance. Furthermore, the solder paste cylinders 7 can be pressed together and, for example, the shape of a squeezed column assume if the distance between the two circuit board substrates 1, 2 produced by the curvature is less than the original distance before the reflow process.

On the one hand, there is no detachment of the solder paste cylinders 7 from the first connection contacts 14 (FIG. 4) and / or second connection contacts 4 (FIG. 2) due to a height distortion caused by thermal expansion, that is to say if the original distance between the two printed circuit board substrates 1, 2 due to the curvature to one another is now greater than the distance between the printed circuit board substrates 1, 2 to one another before the reflow process. As a result, the solder paste cylinders 7 remain in contact with both the first connection contacts 14 of the first printed circuit board substrate 1 and the second connections of the second printed circuit board substrate 2 during the reflow process and subsequently form the electrically conductive connection.

Furthermore, there is no “bursting” of the solder paste cylinders 7, as is the case, for example, with the solder balls, if the original distance between the two printed circuit board substrates 1, 2 due to the curvature is now substantially smaller than the distance between the printed circuit board substrates 1, 2 before the reflow process, because the solder paste cylinder 7 can be squeezed into a squeezed column shape.

Detachment or bursting of the connections as in the prior art can thus be avoided. Due to the formation of the connections with solder paste cylinders 7, a distortion height which arises due to thermal expansion during the melting process can be compensated for up to 2.5 times the original spacing height of the printed circuit board substrates 1, 2.

The printed circuit board arrangement 3 produced in this way can accordingly have melted-on solder paste cylinders 7, some of which have a squeezed column shape or peanut shape. Instead of the reflow process, any suitable melting process can be used.

6 shows an arrangement of the solder paste cylinders 7 on the first printed circuit board substrate 1. These can be arranged essentially in a ring on the first printed circuit board substrate 1, whereby circular also means a rounded square. This ring-shaped arrangement allows warpage / warping to be reduced during the melting process. Furthermore, a more flexible distribution of the solder paste cylinders 7 can be achieved, as can a better weight balance. FIG. 6 also shows a section of solder paste cylinders 7 after the reflow process. These have a "peanut" shape due to warpage.

Reference list of characters:

100 PCB composite (state of the art)

101 first circuit board (prior art)

102 second circuit board (prior art)

103 solder balls (state of the art)

1 first circuit board substrate

2 second circuit board substrate

3 PCB arrangement

4 second connection contacts

5 recess

6 peripherals

7 solder paste cylinders

8 printing template

9a, 9b through channels

10 connection surface

11 bottom

12 surface

14 first contacts

A1, A2 distance

Hl, H2, ZH height

Claims

1. A method for producing a circuit board arrangement (3) characterized by:

- Providing a first circuit board substrate (1),

- Providing a second printed circuit board substrate (2) which is arranged essentially plane-parallel to the first printed circuit board substrate (1), the first printed circuit board substrate (1) having an underside (11), and the second printed circuit board substrate (2) having a surface (12) The surface (12) and the underside (11) are arranged opposite one another,

- Providing first connection contacts (14), which on the underside (11) of the first circuit board substrate

(1) are applied,

Providing second connection contacts which are applied to the surface (12) of the second printed circuit board substrate (2),

- Applying solder paste cylinders (7) to the first connection contacts (14), the application of the solder paste cylinder (7) to the first connection contacts (14) being carried out by a solder paste application method with solder paste, the applied solder paste cylinders (7) each having a solder paste cylinder surface and

- Arranging the second connection contacts (4) of the second circuit board substrate (2) on the solder paste cylinder surfaces of the solder paste cylinder (7).

2. The method for producing a printed circuit board arrangement (3) according to claim 1, wherein the method is further characterized by: melting the solder paste cylinder (7) to form a mechanical and electrically conductive connection between the first connection contacts (14) of the first printed circuit board substrate (1) and At the second connection contacts (4) of the second circuit board substrate

(2).

3. A method for producing a circuit board arrangement (3) according to claim 2, characterized in that the melting on by a reflow method or

Schwallot process is accomplished.

4. The method for producing a printed circuit board arrangement (3) according to claim 2 or 3, characterized in that during melting by thermal expansion of the first printed circuit board substrate (1) and / or the second printed circuit board substrate (2) at least one distortion occurs, so that the solder paste cylinders (7) form a peanut-shaped shape and / or a compact columnar shape at the at least one draft point.

5. A method for producing a printed circuit board arrangement (3) according to one of the preceding claims, characterized in that the application of the solder paste cylinder (7) on the first connection contacts (14) is carried out by a solder paste printing process.

6. The method for producing a printed circuit board arrangement (3) according to one of the preceding claims, characterized in that when the solder paste cylinder (7) is applied by the solder paste application method at least one surface-mountable connection surface (10) made of solder paste, in particular for fastening

SMD components are applied to a connection pad provided on the underside (11).

7. The method for producing a circuit board arrangement (3) according to claim 6, characterized in that the formation of the solder paste cylinder (7) on the first connection contacts (14) by at least a first

Passage channel (9a) in a printing template (8) and the formation of a connection surface (10) by at least one second passage channel (9a) in the printing template (8) takes place, the printing template (8) has a stepped height profile with a first height (Hl) and at least a second height (H2), so that the first passage channel (9b), the first height (Hl) and the second passage channel (9b ) has the second height (H2).

8. PCB assembly (3) comprising

a first circuit board substrate (1),

a second circuit board substrate (2), which is arranged essentially flat parallel to the first circuit board substrate (1), the first circuit board substrate (1) having an underside (11), and the second circuit board substrate (2) having a surface (12) , the surface (12) and the underside (11) being arranged opposite one another,

first connection contacts (14), which on the bottom

(11) of the first printed circuit board substrate (1) and second connection contacts (4) which are on the surface

(12) of the second circuit board substrate (2) are applied,

Solder paste cylinder (7), which between the first connection contacts (14) of the first circuit board substrate

(1) and the corresponding second connection contacts (4) of the second circuit board substrate (2) to form a mechanical and electrically conductive connection between the first connection contacts (14) of the first circuit board substrate (1) and the second connection contacts (4) of the second PCB substrates

(2) are arranged, the solder paste cylinders (7) being applied to the first connection contacts (14) by a solder paste application method using solder paste.

9. Printed circuit board arrangement (3) according to claim 8, characterized in that the solder paste application method is a solder paste printing method.

10. Printed circuit board arrangement (3) according to claim 8 or 9, characterized in that the solder paste cylinder (7) between the first connection contacts (14) of the first printed circuit board substrate (1) and the second connection contacts (4) of the second printed circuit board substrate (2) extending height, the height having a value in the range of 350ym to 700ym.

11. Printed circuit board arrangement (3) according to one of the preceding claims 8 to 10, characterized in that the connection is a soldered connection.

12. Printed circuit board arrangement (3) according to one of the preceding claims 8 to 11, characterized in that the mechanical and electrically conductive connection between the first connection contacts (14) of the first printed circuit board substrate (1) and the second connection contacts (4) of the second printed circuit board substrate ( 2) is accomplished by melting the solder paste cylinder (7).

13. Printed circuit board arrangement (3) according to claim 12, characterized

characterized in that the first printed circuit board substrate (1) and / or the second printed circuit board substrate (2) have at least one warpage due to the melting, the solder paste cylinders (7) having a peanut-shaped shape and / or a compact columnar shape at the at least one warpage.

14. Printed circuit board arrangement (3) according to claim 13, characterized

characterized in that, in the event of a warpage in which the first printed circuit board substrate (1) is at a greater distance from the second printed circuit board substrate (2) than the original distance, the solder paste cylinders (7) have a peanut-shaped shape, and / or in the event of a delay, in which the first circuit board substrate (1) to the second circuit board substrate (2) one, compared to the original Distance, smaller distance, the Lötpastenzy cylinder (7) have a compact columnar shape.

15. Printed circuit board arrangement (3) according to one of claims 8 to 14, characterized in that the first connection contacts (14) and the solder paste cylinder (7) applied thereon are arranged in a ring on the underside (11).

16. Printed circuit board arrangement (3) according to claim 15, characterized

characterized in that the first connection contacts (14) and the solder paste cylinders (7) form a plurality of ring circumferential lines, the solder paste cylinders (7) of the individual ring circumferential lines being equidistant from one another.

17. The printed circuit board arrangement (3) according to one of the preceding claims 8 to 16, characterized in that the first printed circuit board substrate (1) has at least one SMD component arranged on the underside (11) and the second printed circuit board substrate (2) has a recess (5 ), the at least one SMD component at least partially protruding into the recess (5).

18. Printed circuit board arrangement (3) according to one of the preceding claims 8 to 17, produced by the method according to one of the preceding claims 1 to 7.