BARRIER AGAINST BLURRING OF SMT COMPONENTS

Description

[0001] The invention relates to a method for the positionally stable soldering of an SMD component to a circuit carrier.

[0002] Furthermore, the invention relates to a circuit carrier manufactured according to the inventive method. The invention may also relate to a motor vehicle headlight and / or a control unit comprising a circuit carrier according to the invention.

[0003] Prior art already discloses methods that enable the positionally stable soldering of SMD components. For example, AT 515071 A1 discloses a method in which an electronic component to be soldered is fixed to a circuit carrier by means of adhesive dots, whereby the adhesive dots are hardened before a soldering process is started in order to prevent the components from shifting.

[0004] It is generally known that the volume of solder decreases during the soldering process due to flux outgassing. This reduction can be as much as 50%. Therefore, if an electronic component is glued in place, it must be ensured that a sufficient excess of solder is present to guarantee that an adequate amount of solder is available at the joint, despite the shrinkage. If, as in AT 515071 A1, the component to be soldered is fixed in position before the soldering process, the decrease in the volume of the solder is compensated for by "overpressure." This refers to applying excess solder to areas extending beyond the actual contact point to allow this excess solder to flow to the contact point during the melting process.Otherwise, a solder joint could be defective, containing larger air inclusions, or a full-surface, continuous contact might not be possible due to a lack of solder material. GB 2 304 999 A discloses a method for soldering an SMD component onto a circuit board.

[0005] However, there are situations where such overprinting is not possible, for example, because adjacent components prevent it, or because the solder pads on a printed circuit board layout are already fixed and an existing layout is simply to be populated with a differently sized electronic component without making any changes to the circuit carrier or the solder pads. At the same time, the most economical manufacturing process possible should be ensured.

[0006] One object of the invention is therefore to provide a method that offers a solution to the problem mentioned above. This object is achieved with a method of the type mentioned at the outset, in which the following steps are provided according to the invention: a) Providing a circuit carrier comprising at least one solder paste-coated substrate contact surface, which is configured for electrical, thermal and / or mechanical contacting of the SMD component to be connected, wherein the circuit carrier is permeated, at least in the area of ​​the substrate contact surface, with a number of filled vias that are not wettable with molten solder (these can be, for example, electrical insulating material such as resin, i.e., epoxy; alternatively, electrically conductive materials or combinations thereof can be used, such as an epoxy filled with metal particles with increased thermal conductivity; the use of ceramic-filled epoxy is also conceivable), b) Applying at least one adhesive point to the circuit carrier in such a way thatthat this adhesive point delimits the solder paste-coated carrier board contact surface at an edge point assigned to at least one side of the solder paste, c) placing an SMD component comprising at least one component contact surface onto the solder paste-coated carrier board contact surface in such a way that the at least one component contact surface electrically, thermally and / or mechanically contacts the carrier board contact surface via the intervening solder paste, wherein the placement is carried out in such a way and the position of the at least one adhesive point in step b) is chosen such that the SMD component rests on the solder paste without contact with the at least one adhesive point, d) waiting for a curing process of the at least one adhesive point for a predefinable time period t, optionally at a predefinable temperature T, e) heating, melting and subsequent cooling of the solder paste to produce an electrical,thermal and / or mechanical connection between the at least one component contact surface of the SMD component and the at least one carrier board contact surface of the circuit carrier, wherein a barrier is formed by means of the at least one adhesive point such that, firstly, a vertical sinking of the SMD component in the molten state of the solder paste is enabled, and secondly, a horizontal spreading of the SMD component on the molten solder paste in the direction of the barrier is mechanically limited by the barrier, wherein at least one adhesive point is spherically shaped.

[0007] The method according to the invention makes it possible, on the one hand, to permanently fix the position of the SMD component in a horizontal plane and prevent the component from shifting, and on the other hand, to allow the component to sink relative to the circuit carrier, thus enabling a homogeneous solder joint that is largely free of voids. In the present invention, the adhesive points—in contrast to AT 515071 A1—are not used for the absolute fixation of the SMD component, but rather to limit the position or movement of the component within a horizontal plane. The invention also takes advantage of the fact that the presence of vias (in particular the presence of asymmetrically arranged vias with respect to the contact area to be soldered), which are not wettable with solder, strongly promotes the detrimental shifting of SMD components during the soldering process.The extent of blurring is significantly increased. While a slight float is tolerable in some situations, a larger extent of blurring is problematic. In this document, the terms "float" and "blurring" are understood as follows: The term "float" is understood as movement of the component on the liquid solder within a non-critical range, i.e., to an extent that does not impair the functionality of the solder joint and the deviation from the intended position is small enough not to trigger a (pseudo-)defect during subsequent AOI (automated optical inspection). The term "blurring" is understood as a floating movement that is problematic to such an extent that, for example, the solder joint may be impaired and / or the deviation from the intended position is so large that (pseudo-)defects are detected during any AOI.Since applying adhesive dots as a boundary involves technical and economic effort, they should only be used where their application is economically justified. Therefore, adhesive dots are selectively applied to components affected by such vias. The vias (also called through-holes) used are primarily type 5 vias, where the through-hole is formed by a copper sleeve embedded in the substrate, which is then filled with resin, for example. Heat conduction occurs primarily through the copper sleeve. Due to the filling, solder cannot penetrate the via or wet it, which can lead to forces acting on the component during the soldering process that promote blurring. This is especially true when the vias are asymmetrically arranged relative to the component being soldered.

[0008] The term "horizontal" refers to an orientation that is parallel to a plane formed by the substrate contact surface. After step e), a further step f) may be provided, which includes cooling and removal of the assembled circuit carrier. The term "SMD component" refers to any component that is attached to the surface of the circuit carrier – i.e., it does not use "through-hole" technology. SMD components can also be electrically connected to the circuit board, for example, by top-contact bonding.

[0009] In principle, at least one adhesive point is provided for forming the barrier. This may suffice in situations where, for example, it can be observed that the components rotate or drift in only one direction. In such cases, one adhesive point acting opposite to the component's direction of rotation or drift is sufficient. Component pins can then be used for the remaining positioning. Of course, two or more adhesive points can also be provided. The number of adhesive points can be freely chosen. All features mentioned in the present invention with regard to "the at least one adhesive point" can—unless otherwise specified—also be applied to two or more adhesive points.

[0010] The vias can be, for example, Type 5 or Type V vias. These are very often explicitly included in the area of ​​the PCB pad to minimize thermal resistance. In particular, the presence of vias arranged asymmetrically with respect to the substrate contact area promotes thermal fusion, which is why the provision of barriers has proven particularly advantageous in the case of such asymmetrically arranged vias.

[0011] In particular, it may be provided that the substrate contact surface coated with solder paste in step a) is surrounded by a solder mask layer, with the at least one adhesive dot being located on the solder mask layer and / or on a section of the substrate contact surface not coated with solder paste. The adhesive may be formulated to adhere particularly well to the solder mask layer. This also prevents the adhesive from coming into contact with the solder. Alternatively, as mentioned, the adhesive dot can be applied to the pad (i.e., the PCB contact surface) on its own or simultaneously to the pad and / or the solder mask layer of the PCB. Overlap with the solder paste on the pad is also acceptable, although not desirable.

[0012] Furthermore, it can be provided that the height of the at least one adhesive point is at least 40%, preferably at least 60%, and particularly preferably at least 100% of the height of a solder paste deposit formed by the solder paste in its unmelted state, with the barrier being formed exclusively by the at least one adhesive point itself. In this way, a boundary can be created by the adhesive points themselves without the need for additional components. Advantageously, the height of the adhesive points is chosen such that the component to be secured will abut the adhesive point if the solder becomes displaced. It can be taken into account that the solder loses approximately 50% of its volume during the soldering process. For chip components, e.g., ohmic resistors, the paste can, for example, be printed with a height of 120 µm.

[0013] At least one adhesive point is shaped like a spherical cap.

[0014] This shape can be determined by the surface tension of the adhesive used, as well as by the application method. For example, so-called "jet dispensers" can be used. Such a "jet dispenser" dispenses dots of adhesive, which, due to the deformation of the jetted adhesive "particle" upon contact with the circuit board, usually have a shape similar to a spherical cap. Using this method, it is also possible to create other geometries with these individual dots, such as so-called adhesive beads. However, there are also so-called volumetric dispensers, which dispense the adhesive continuously. These can be used to create lines or similar geometric shapes from the adhesive.

[0015] Furthermore, it may be provided that at least one initial adhesive point is extended linearly to form a linear barrier. This includes both adhesive beads and adhesive lines.

[0016] In particular, it can be provided that at least a second adhesive point is included, which preferably contacts the first adhesive point, wherein the second adhesive point is designed in a linear fashion such that, together with the first adhesive point, a substantially L- or U-shaped contour is formed that at least partially encloses the SMD component. In this way, the blurring of the components to be attached in a further direction can be largely prevented.

[0017] Furthermore, it can be provided that the height of at least one adhesive point is at least 50 micrometers, preferably at least 100 micrometers.

[0018] In particular, it can be provided that, after step b) and before step d), at least one boundary element is placed on the at least one adhesive point, and the barrier is formed using the boundary element. The use of boundary elements allows the barrier to be positioned closer to the SMD component to be attached. The geometric shape of the boundary element can also be specifically adapted to the shape of the SMD component. The boundary element can, for example, be U-shaped, L-shaped, or even straight. Shapes made of polymers or plastics, as well as ceramics and metals, can be used. Using a shape made of polymer or ceramic offers economic advantages. The melting temperature of the boundary element material used should be above the maximum temperature of the soldering process, and the surface must be designed in such a way that the adhesive adheres.

[0019] Furthermore, it can be provided that the at least one adhesive point consists of a thermosetting material and that the curing of the at least one adhesive point according to step d) is carried out by increasing the temperature of the circuit carrier together with the at least one adhesive point, for example during a reflow soldering process, wherein the temperature required for thermosetting is below the melting temperature of the soldering material.

[0020] In particular, it may be provided that the adhesive material is selected in such a way that the adhesive volume decreases by a maximum of 10% during curing.

[0021] Furthermore, the adhesive material can be designed to be thermosetting and selected such that it expands during curing when heat is applied, as described in step d). An advantage of an expanding material is that, unlike a spherical cap, its height does not increase continuously with a low slope, but rather has a steeper edge, which makes it more difficult for a component to slide up it. Besides liquid adhesives, other adhesives could also be used. For example, a paste-like, dispensable adhesive material could be used that has the following properties: heat resistance, volume expansion when heated, adhesion to the solder mask, and hardening largely before the solder's melting temperature is reached. Here, for example, a polyurethane-based foam or silicone could also be used.The idea is that the dispensed point made of such a material expands when heated, thus forming a barrier that also widens laterally and upwards, making it much more difficult for the component to overcome this type of barrier than an adhesive point, which usually has a largely continuous rise up to its maximum height.

[0022] In particular, it can be provided that the at least one adhesive point is applied by means of a dispenser and the SMD component by means of a pick-and-place machine, wherein the at least one adhesive point is positioned in step b) such that it has at least a safety distance from the edge of the intended position of the SMD component, wherein this safety distance is calculated as the sum of the positioning tolerances of the dispenser and the pick-and-place machine, the size tolerance of the at least one adhesive point, and the component tolerance of the SMD component, and is, for example, at least 50 micrometers. Currently, the safety distance of the adhesive point to an SMD component is at least 50 micrometers, and, for example, a maximum of 300 micrometers. As mentioned, component tolerances should be taken into account, i.e., not every component is the same size. For example, a difference of + / - 0.1 mm in component size from the manufacturer's specifications is possible.

[0023] Furthermore, it can be provided that the SMD component has a rectangular base and that at least one adhesive point is positioned such that, after placement of the SMD component and while maintaining the safety distance specified in step b), the adhesive point is located in close proximity to one side of the rectangular base. The expression "in close proximity to one side" means that only the minimum distance, e.g., 50 micrometers, is required. Alternatively, the distance could be chosen relative to a corner of the rectangular base. The number of adhesive points can be selected such that exactly one adhesive point is assigned to each side and / or corner of the SMD component. This limits the component's potential for blurring in any direction.The term "rectangular base" does not necessarily mean an exactly rectangular shape - of course, corners can be flattened or rounded, or component pins can extend beyond this base (this applies, for example, to an LFPAK / SOT669 design).

[0024] Furthermore, the invention relates to a circuit carrier manufactured according to the inventive method. The invention can also further relate to a motor vehicle headlight comprising a circuit carrier according to the invention.

[0025] In other words, the invention can also be described as follows: Certain SMT packages, such as Powerflat 5x6 or LFPAK / SOT669, but also TO-277A, have individual small component pins (or connection pins; e.g., N-channel MOSFET: gate and source) on one side, while the majority of the package underside consists of a large, usually continuous thermal pad (e.g., N-channel MOSFET: drain). The components are typically placed very precisely onto the solder paste deposits (<50µm accuracy), but due to factors such as suboptimal footprint dimensions, via technology, or finish, it can happen that these components become misaligned with the thermal pad during the reflow process, meaning that the overlap between component pads and PCB pads is no longer ideal. This often leads to false detections (these are referred to as pseudo-defects).The component is (usually) functional, but its positional deviation exceeds the permissible tolerance for AOI during automated optical circuit board inspection (AOI). This deviation can lead to problems, such as poorly formed solder joints, as the component is out of position by more than the allowed tolerance. A simple solution, which has long been an industry standard, is to adhere the component with SMT adhesive, for example, at two or four points along the edge of the package, to prevent it from shifting during reflow. Direct component adhesion works as follows: Paste deposits are printed, and then the adhesive dots are applied next to them so that, during subsequent component placement, its edges, for example, are embedded in the adhesive. When the assembled board then enters the reflow oven, the adhesive will cure first, typically long before the solder paste melts.This holds the component in its precise placement position and prevents it from shifting on the liquid solder. However, the disadvantage of this well-known method is the amount of solder required for the resulting solder gap: When a small component is placed onto the paste (with a typical force of 2-6 N), it is pressed slightly into the paste deposit and lies, for example, at a height of 50-100 µm; with larger components, as in this case, the paste is compressed less, and the component lies at a height comparable to the stencil thickness (100-150 µm). During reflow, the solder paste melts and loses approximately 50% of its volume, as only the tin content remains in the solder joint. Without adhesive fixation, the component will sink downwards from its initial height, as mentioned earlier, resulting in a much smaller solder gap. Adhesive fixation of the component should reduce the solder joint thickness with the same amount of paste – for example…in a lateral direction. This was previously compensated for by printing more paste to the side of the pad and allowing the molten solder to flow under the component via inlet channels during reflow (see, for example, EP 323 3345 A1). For component designs with relatively large solder paste-coated substrate contact areas, and thus also solder paste segmentation (necessary for flux outgassing during soldering), a relatively high lateral overpressure was therefore required. All these precautions had to be taken into account during the PCB design and could not be implemented later in the product lifecycle without a complex change process or revalidation (e.g., due to a change in solder gap height).

[0026] The invention represents a departure from the adhesive fixing of SMD components and makes it possible to create barriers on the circuit board that prevent certain components placed within or next to the adhesive from shifting during the soldering process. Furthermore, the components should not come into contact with the adhesive during application, thus preventing them from forming a solder gap as if they were not glued. In contrast to the prior art, the shifting of components during the soldering process is not prevented by direct gluing, but rather by using positionally and dimensionally stable adhesive dots or components mounted on them, positioned close to the component, as a shifting barrier during reflow soldering.

[0027] The following sequence of events can occur during the SMT manufacturing process: After the solder paste is printed, SMT adhesive dots are placed close to the imaginary edge of the component. The component is then placed using the pick-and-place machine without touching the adhesive. Depending on the design, there are two possibilities: • Variant A: The adhesive dots themselves later form the barrier; this completes the placement process. • Variant B: An additional barrier element is placed next to the component on the adhesive dot in this step. The adhesive dots cure quickly in the reflow oven and remain in position. Only then does the solder under the component begin to melt. The component begins to float on the liquid solder, but any blurring is (largely) prevented by the already hardened adhesive dot (Variant A) or the barrier element fixed with adhesive (Variant B). This results in significantly less component misalignment than without a barrier.

[0028] While the components could blur by several hundred micrometers without hindrance (and thus be outside the permissible AOI tolerances), the blurring can be reduced to an acceptable level with the method described (for example, 100-200 micrometers).

[0029] The invention is explained in more detail below with reference to an exemplary and non-limiting embodiment, which is illustrated in the figures. These show Figure 1a is a schematic representation of a section of a circuit carrier with an SMD component to be attached to it according to the prior art, Figure 1a is a blurred attached SMD component according to Fig. 1a Figure 2a shows a sectional view of an embodiment according to the invention in the unsoldered state, Figure 2b shows the sectional view according to Fig. 2a in the soldered state, Figure 2cein detail of the Fig. 2b Figure 2, another detail of the Fig. 2b , in which it can be seen that the SMD component abuts a barrier and is held in its position by it. Figures 3a to 3d show different variants of adhesive point configurations according to the invention, and Figures 4a to 4c show different variants of boundary body configurations. , that do not belong to the invention.

[0030] In the following figures, unless otherwise stated, the same reference symbols denote the same features.

[0031] Figur 1a Figure 1 shows a schematic representation of a section of a circuit carrier 2 with an SMD component 1 to be attached to it, according to the prior art. As shown in Figure 2 Fig. 1b As can be seen, component 1 is blurred during the soldering process on a solder deposit 3 (not shown in the figure) and is firmly soldered in this blurred final position.

[0032] Figur 2a Figure 1 shows a sectional view of an embodiment according to the invention in the unsoldered state. It depicts an arrangement on which the method according to the invention is carried out. The invention relates to a method for the positionally stable soldering of an SMD component 1 to a circuit carrier 2 and, in the illustrated embodiment, comprises the following steps a) to e): a) Providing a circuit carrier 2 comprising at least one substrate contact surface 2a coated with solder paste 3, which is configured for electrical, thermal, and / or mechanical contact with the SMD component 1 to be connected. The circuit carrier 2 is perforated, at least in the area of ​​the substrate contact surface 2a, with a number of filled vias 6 that are not wettable by molten solder. This number is generally variable and not limited to a specific value. b) Applying – in this embodiment – ​​two adhesive points 4a and 4b to the circuit carrier 2 such that these adhesive points 4a and 4b delimit the substrate contact surface 2a coated with solder paste 3 at edge points R a and R b, respectively, assigned to one side of the solder paste 3. An edge point is understood to be a point assigned to one side of the solder paste 3 or to an overlying side of the SMD component 1.The term "limit" is understood here to mean "delimitation." This does not mean that the edge point is contacted by the adhesive point 4a or 4b during application. On the contrary, a minimum distance is maintained with respect to the SMD component 1, as will be mentioned later. The term "limit" refers to limiting the blurring process of the SMD component 1, and the edge points, in particular Ra and Rb, each designate a point on exposed edges or protrusions of the component 1 that, for example, encounters a barrier 5 or an adhesive point 4a or 4b during blurring. c) Placing an SMD component 1, comprising at least one component contact surface 1a, onto the substrate contact surface 2a coated with solder paste 3, such that the at least one component contact surface 1a makes electrical, thermal, and / or mechanical contact with the substrate contact surface 2a via the intervening solder paste 3.The placement is carried out as follows, and the position of the adhesive points 4a and 4b in step b) is chosen such that the SMD component 1 rests on the solder paste 3 without contact with the adhesive points 4a and 4b. d) Waiting for a curing process of the two adhesive points 4a and 4b for a predefinable duration t, for example, one minute (more precisely, this process can take up to 1-5 minutes depending on the temperature - in typical reflow at ~150°C plateau phase at the beginning, this process will take approximately 90-120 seconds), e) Heating, melting, and subsequent cooling of the solder paste 3 to create an electrical, thermal, and / or mechanical connection between the at least one component contact surface 1a of the SMD component 1 and the at least one substrate contact surface 2a of the circuit carrier 2. Using the adhesive points 4a and 4b, which are located in . Figur 2b As shown in the already cured state, a barrier 5 is formed such that, firstly, a vertical sinking of the SMD component is permitted in the molten state of the solder paste 3, and secondly, a horizontal spreading of the SMD component on the molten solder paste 3 in the direction of the barrier 5 is mechanically limited by the barrier 5. In this case, the barrier 5 is formed jointly by the two adhesive points 4a and 4b.

[0033] Fig. 2c shows a detail of the Fig. 2b This shows how the now solidified solder 3 has changed in its distribution due to the influence of the via 6: Because the via is also located in the edge region of the SMD component 1's contact, and because the via is not wettable by solder 3, the solder 3 has retreated to an area below the SMD component 1. This "retraction" causes mechanical forces on the SMD component 1, which promote its displacement. This displacement does not always occur – in this case, however, the component 1 did not remain in its position. Fig. 2d In contrast, it shows a scenario in which component 1 collides with barrier 5 and is held in position by it.

[0034] In Figuren 2a und 2b It can be seen that the carrier board contact surface 2a, coated with solder paste 3 in step a), is surrounded by a solder mask layer 8, with the two adhesive points 4a and 4b being located on the solder mask layer 8. However, the adhesive points do not necessarily have to be placed on the circuit board layer, but can also be located, for example, on the carrier board contact surface 2a of the circuit board.

[0035] The height h 1 (see Fig. 2a The area of ​​the adhesive points 4a, 4b, 4c, 4d, 4e is at least 40%, preferably at least 60%, particularly preferably at least 100% of the height h 2 (see Fig. 2a ) a solder paste deposit 3a formed by the solder paste 3 in the unmelted state, wherein the barrier 5 is formed exclusively by the adhesive points 4a and 4b themselves.

[0036] In the Figuren 2a und 2b It can be seen that the adhesive points 4a and 4b are shaped like spherical caps.

[0037] Figuren 3a bis 3d The illustrations show different variations of adhesive dot configurations according to the invention. Fig. 3a The use of a single adhesive dot 4a is shown, which is positioned on one side of the SMD component 1. Fig. 3b shows a variant in which adhesive points 4a and 4b are positioned at one corner of the SMD component 1. Fig. 3c shows a variant in which, in addition to the corner adhesive points 4a and 4b, an adhesive point 4c is also provided on the side. Fig. 3d Figure 1 shows the use of five successively arranged adhesive points 4a, 4b, 4c, 4d, 4e, which together extend linearly to form a linear barrier 5 ("adhesive bead"). In principle, numerous other configurations are conceivable. For example, it can be provided that at least one second adhesive point is included, which preferably contacts the first adhesive point, wherein the second adhesive point is designed linearly such that, together with the first adhesive point, a contour essentially L- or U-shaped is formed that at least partially encloses the SMD component 1.

[0038] The Figuren 4a bis 4c The figures show different variants of boundary body configurations that are not part of the invention. Accordingly, after step b) and before step d), at least one boundary body 7 is placed on the at least one adhesive point 4a (not shown in the figures). The barrier 5 is formed with the help of the boundary body 7. The boundary body can be U-shaped ( Fig. 4c ) or L-shaped ( Fig. 4b ) be formed or have a straight shape ( Fig. 4a ) have. Multiple boundary bodies 7 can also be used.

[0039] Preferably, the adhesive points consist of a thermosetting material. The thermosetting temperature is below the melting temperature of the material being soldered.

[0040] In the Figuren 3a bis 4c It can be seen that the SMD component 1 each has a rectangular base area 1c (reference symbol see Fig. 3a and 4a ) exhibits. From Fig. 3aIt is evident that the adhesive point 4a is positioned so that, after the SMD component 1 has been placed on it, it lies in the immediate vicinity of one side of the rectangular base 1c, while maintaining the safety distance s in step b).

[0041] The invention is not limited to the embodiments shown, but is defined by the entire scope of protection of the claims.

[0042] Any reference numerals in the claims are exemplary and serve only to make the claims easier to read, without limiting them.

Claims

1. Method for positionally stable soldering of an SMD component (1) to a circuit carrier (2), comprising the following steps: a) providing a circuit carrier (2) comprising at least one carrier plate contact surface (2a) coated with solder paste (3), which is designed for electrical, thermal, and / or mechanical contacting of the SMD component (1) to be connected, wherein the circuit carrier (2) is interspersed, at least in the area of the carrier plate contact surface (2a), with a number of filled through-plated holes (6) that cannot be wetted with molten solder, b) Applying at least one adhesive dot (4a, 4b, 4c, 4d, 4e) to the circuit carrier (2) in such a way that this adhesive dot (4a, 4b, 4c, 4d, 4e) delimits the carrier plate contact surface (2a) coated with solder paste (3) at at least one edge point (Ra, Rb) associated with the solder paste (3), c) Placing an SMD component (1) comprising at least one component contact surface (1a) onto the carrier plate contact surface (2a) coated with solder paste (3) in such a way that the at least one component contact surface (1a) is electrically, thermally, and / or mechanically contacted to the carrier plate contact surface (2a) via the solder paste (3) located between them (3) between them, the placement being carried out in such a way and the position of the at least one adhesive point (4a, 4b, 4c, 4d, 4e) in step b) being selected in such a way that the SMD component (1) rests on the solder paste (3) without contact with the at least one adhesive point (4a, 4b, 4c, 4d, 4e) on the solder paste (3), 4c, 4d, 4e) on the solder paste (3) without contact, d) waiting for the at least one adhesive point (4a, 4b, 4c, 4d, 4e) to cure for a predeterminable period of time t, e) heating, melting, and subsequent cooling of the solder paste (3) to produce an electrical, thermal, and / or mechanical connection between the at least one component contact surface (1a) of the SMD component (1) and the at least one carrier plate contact surface (2a) of the circuit carrier (2), wherein, with the aid of the at least one adhesive dot (4a, 4b, 4c, 4d, 4e) is used to form a barrier (5) in such a way that, firstly, vertical sinking of the SMD component is possible when the solder paste (3) is in a molten state and, secondly, horizontal blurring of the SMD component on the molten solder paste (3) in the direction of the barrier (5) is mechanically limited by the barrier (5), wherein at least one adhesive point (4a, 4b, 4c, 4d, 4e) is designed in the shape of a spherical cap.

2. Method according to claim 1, wherein the carrier plate contact surface (2a) coated with solder paste (3) in step a) is surrounded by a solder resist layer (8), wherein the at least one adhesive point (4a, 4b, 4c, 4d, 4e) is located on the solder resist layer (8) and / or on a section of the carrier plate contact surface (2a) that is not coated with solder paste (3).

3. Method according to claim 1 or 2, wherein the height (h1) of the at least one adhesive point (4a, 4b, 4c, 4d, 4e) is at least 40%, preferably at least 60%, and particularly preferably at least 100% of the height (h2) of a solder paste deposit (3a) formed by the solder paste (3) in the unmelted state, wherein the barrier (5) is formed exclusively by the at least one adhesive point (4a, 4b, 4c, 4d, 4e) itself.

4. Method according to one of the preceding claims, wherein the height (h1) of the at least one adhesive point (4a, 4b, 4c, 4d, 4e) is at least 50 micrometers, preferably at least 100 micrometers.

5. Method according to claim 1 or 2, wherein after step b) and before step d), at least one limiting body (7) is placed on the at least one adhesive point (4a), and the barrier (5) is formed with the aid of the limiting body (7).

6. Method according to one of the preceding claims, wherein the at least one adhesive point (4a, 4b, 4c, 4d, 4e) consists of thermosetting material and the curing of the at least one adhesive point (4a, 4b, 4c, 4d, 4e) according to step d) is carried out by increasing the temperature of the circuit carrier (2) together with the at least one adhesive point (4a, 4b, 4c, 4d, 4e), which is carried out, for example, in the course of a reflow soldering process, wherein the temperature required for heat curing is below the melting temperature of the soldering material.

7. Method according to one of the preceding claims, wherein the adhesive material is selected such that the adhesive volume decreases by a maximum of 10% during curing.

8. Method according to one of claims 1 to 6, wherein the adhesive material is thermosetting and is selected such that it expands during curing in accordance with step d) when heat is applied.

9. Method according to one of the preceding claims, wherein the at least one adhesive dot (4a, 4b, 4c, 4d, 4e) is applied by means of a dispenser and the SMD component (1) is applied by means of an automatic placement machine, wherein the at least one adhesive dot (4a, 4b, 4c, 4d, 4e) is positioned in step b) in such a way that it has at least one safety distance (s) to the edge area of the target position of the SMD component (1), wherein this safety distance (s) is formed from the sum of the positioning tolerances of the dispenser and the automatic placement machine, the size tolerance of the at least one adhesive dot (4a, 4b, 4c, 4d, 4e) and the component tolerance of the SMD component (1), and is, for example, at least 50 micrometers.

10. Method according to claim 9, wherein the SMD component (1) has a rectangular base area (1c) and the at least one adhesive point (4a, 4b, 4c, 4d, 4e) is positioned such that the at least one adhesive point (4a, 4b, 4c, 4d, 4e) is located in the immediate vicinity of one side of the rectangular base area (1c) after assembly with the SMD component (1), while maintaining the safety distance (s) in step b).

11. Method according to one of the preceding claims, wherein in step b) the number of adhesive dots (4a, 4b, 4c, 4d, 4e) is selected such that exactly one adhesive dot (4a, 4b, 4c, 4d, 4e) is assigned to each side and / or corner of the SMD component (1).

12. Circuit carrier (1) manufactured according to a method according to one of the preceding claims.