METHOD FOR SOLDERLESS ELECTRICAL PRESS-IN CONTACTING OF ELECTRICALLY CONDUCTIVE PRESS-IN PINS IN CIRCUIT BOARDS

Abstract

A method is described for solderless electrical press-in contacting of conductive press-in pins in circuit boards, the method comprising the following steps: Providing a circuit board having at least one contacting opening for press-in contacting; providing at least one press-in component having at least one conductive press-in pin; providing a sonotrode for exerting a force and for applying ultrasonic energy. In order to electrically and mechanically contact press-in pins to a circuit board by means of ultrasonic press-in technology, it is provided that the press-in component together with its press-in pin, is fixated during a press-in step, in particular held firmly in place, and that a force and ultrasonic energy are directly applied to the circuit board by means of the sonotrode such that the circuit board is pressed at the location of its contacting opening onto the press-in pin, not directly acted upon by the sonotrode, of the press-in component.

Claims

1.-9. (canceled)

10. A method for solderless electrical press-in contacting of at least one electrically conductive press-in pin in a circuit board, comprising: providing the circuit board, wherein the circuit board includes at least one contacting opening for a press-in contacting, and wherein the at least one contacting opening is routed essentially perpendicularly through the circuit board; providing at least one press-in component having the at least one electrically conductive press-in pin; providing a sonotrode for exerting a force and for applying ultrasonic energy; and fixating the at least one press-in component having the at least one press-in pin during a press-in step, wherein, in the press-in step, the force and the ultrasonic energy is applied directly to the circuit board with the aid of the sonotrode, in such a way that the circuit board is pressed onto the at least one press-in pin, not directly acted upon by means of the sonotrode, of the at least one press-in component at a location of the at least one contacting opening.

11. The method as recited in claim 10, wherein the at least one press-in component is held firmly in place by the fixating.

12. The method as recited in claim 10, further comprising prior to the press-in step, fitting the circuit board with components, wherein the fitting of components on the circuit board is completely finished except for the press-in step for the fitting with the at least one press-in component.

13. The method as recited in claim 12, wherein the sonotrode includes recesses on a side facing the circuit board at locations that during the press-in step lie opposite from the locations, fitted with the components, of a side of the circuit board facing the sonotrode.

14. The method as recited in claim 10, wherein: the circuit board has a first side facing the at least one press-in component, and has a second side facing away from the first side, and the sonotrode is set down on the second side during the press-in step.

15. The method as recited in claim 14, wherein the sonotrode covers at least 75% of an area of the second side.

16. The method as recited in claim 10, wherein: during the press-in step, the sonotrode presses the circuit board onto the at least one press-in pin along an extension direction of the at least one contacting opening across a distance, and a first force and a first ultrasonic energy are applied to the sonotrode during the press-in step along the distance.

17. The method as recited in claim 16, wherein, after covering the distance: the sonotrode exerts a second force on the circuit board, the second force is very low in comparison with the first force, the sonotrode applies a second ultrasonic energy to the circuit board, and the second ultrasonic energy is one of lower than, equal to, and greater than the first ultrasonic energy.

18. The method as recited in claim 17, wherein the second force amounts to maximally 10% of the first force.

19. The method as recited in claim 17, wherein the second ultrasonic energy is greater by at least 25% than the first ultrasonic energy.

20. The method as recited in claim 17, wherein the second ultrasonic energy is lower by at least 25% than the first ultrasonic energy.

21. The method as recited in claim 10, wherein the at least one press-in pin is made of a material that includes one of a metal and a metal alloy from a group including one of aluminum, copper, and iron.

22. The method as recited in claim 10, wherein the at least one press-in pin includes a solid design.

23. The method as recited in claim 22, wherein the at least one press-in pin is one of without a cavity and without a flexible section.

24. The method as recited in claim 10, further comprising providing a plurality of press-in pins on the at least one component, wherein the circuit board includes a number of contacting openings that corresponds at least to the number of press-in pins of the at least one component.

25. The method as recited in claim 24, wherein the plurality of press-in pins includes one of at least two press-in pins and at least four press-in pins.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1a shows a cross-section through a first specific embodiment of a system for executing the method of the present invention, prior to the press-in step.

[0032] FIG. 1b shows the system from FIG. 1a, following the press-in step.

[0033] FIG. 2a shows a cross-section through a second specific embodiment of a system for executing the method of the present invention, prior to the press-in step.

[0034] FIG. 2b shows the system from FIG. 2a following the press-in step.

[0035] FIG. 3 shows a specific embodiment of the method according to the present invention.

DETAILED DESCRIPTION

[0036] All of the figures are merely schematic representations of the method of the present invention or of steps of the present method or of arrangements in various steps of the method according to exemplary embodiments of the present invention. Clearances and proportions are especially not represented true to scale in the figures. Corresponding elements in the various figures have been provided with the same reference numerals.

[0037] FIG. 1a shows a system for executing the method of the present invention. The system in FIG. 1a illustrates the present method in the step prior to the press-in step. In order to execute the present method for solderless electrical press-in contacting of electrically conductive press-in pins 210 in circuit boards 100, a circuit board 100, a sonotrode 500 for exerting a force and for applying ultrasonic energy, as well as a press-in component 200 having two press-in pins 210, which are visible in this cross-section, are provided.

[0038] Circuit board 100 is disposed between press-in component 200 and sonotrode 500.

[0039] Circuit board 100 may be developed from FR4 material or better, or as a ceramics circuit board. The circuit board has a first side 102, which faces press-in component 200. In addition, circuit board 100 has a second side 104, which points away from first side 102. Second side 104 is facing sonotrode 500.

[0040] Circuit board 100 has at least one circuit trace 110, which is situated within circuit board 100 in the exemplary embodiment shown. It is also quite easily possible to place the at least one circuit trace 110 on one of surfaces 102, 104 of circuit board 100. Circuit board 100 has contacting openings 130 that reach through or penetrate circuit board 100. Contacting openings 130 may be connected to circuit trace 110 in an electrically conductive manner. Contacting openings 130 may have a metallic coating on their inner walls 132; preferably, inner walls 132 of contacting openings 130 are metallized completely. Circuit board 100 may be fitted with electrical and/or electronic components 150 which are mounted on circuit board 100. For example, electrical and/or electronic components 150 may be passive components 152 such as capacitors or resistances but also integrated circuits such as an application-specific integrated circuit (ASIC) 154. These components 150 are able to be mounted on circuit board 100 with the aid of a soldering process or a bonding process, for example.

[0041] Press-in component 200 has press-in pins 210, which are facing toward circuit board 100, of which two can be seen in the illustrated cross-sectional view. Press-in pins 210 have free ends 212 facing circuit board 100, which are in alignment with contacting openings 130 of circuit board 100. Press-in component 200 is firmly fixed in place, the holding mechanism for fixating the press-in component not being shown in the figure. Press-in component 200 is developed as a type of plug housing in the exemplary embodiment shown, in which press-in pins 210 are fastened in a plastic-extruded manner, for example. On the side facing circuit board 100, press-in component 200 is designed in the shape of a cup and a circumferentially extending outer wall 242, for instance, delimits an interior 240 of the cup shape. Press-in pins 210 are disposed in interior 240 of the cup shape. Spacer pieces 220 or bearing elements 220 on which circuit board 100 is able to make contact when pressed onto press-in pins 210 (FIG. 1b), are disposed in interior 240 of the cup shape on a bottom 244 of the cup shape. Via their free ends 212, press-in pins 210 project along a press-on direction 280 beyond bearing elements 220 by a distance S.

[0042] On its side facing circuit board 100, sonotrode 500 is provided with a bearing surface 502 which is suitable to be placed directly on second side 104 of circuit board 100. On its outer side, sonotrode 500 includes a collar-shaped outer wall 520, which delimits circuit board 100 when sonotrode 500 sets down on circuit board 100. Located on the side of the sonotrode that faces circuit board 100 are recesses 510 in bearing surface 502. Recesses 510 are provided at the particular locations that come to lie above the respective locations of circuit board 100 in which components 150 are situated on circuit board 100 when sonotrode 500 is placed on circuit board 100. In this way it is ensured that sonotrode 500 comes into direct contact, by way of its contact area 502, with second side 104 of the circuit board in all locations, that is to say, without touching an already mounted component 150 along press-on direction 280 and without therefore applying direct ultrasound to such a component. Means (not shown here) for connecting sonotrode 500 to circuit board 100 during the press-in step are provided on sonotrode 500. For example, sonotrode 500 may aspirate circuit board 100 by means of a vacuum at its bearing surface 502. It is also possible to screw sonotrode 500 to circuit board 100 for the press-in step or to temporarily firmly connect it to circuit board 100 by magnetic force.

[0043] In FIG. 1a, the press-in step or the press-on process is shown at an instant at which circuit board 100 with its contacting openings 130 has been placed onto free ends 212 of contact pins 210 of press-in component 200 and in which sonotrode 500 has not yet been brought into contact with circuit board 100. The method can also be executed in a form that is not shown here, in such a way that circuit board 100 is first attached to sonotrode 500 and circuit board 100, connected to sonotrode 500, is then set down on press-in pins 210. To then press circuit board 100 onto press-in pins 210, sonotrode is pressed against press-in pins 210 using a first force (F1) and a first ultrasonic energy (|1) in press-on direction 280. Press-in component 200 is firmly held in place in the process.

[0044] FIG. 1b shows the system from FIG. 1a in the state in which circuit board 100 is pressed on press-in pins 210. Circuit board 100 has been pressed onto press-in pins 210 of press-in component 200 by a distance S. Press-in pins 210 project through circuit board 100. It should be noted that sonotrode 500 also includes recesses 510 for free ends 212 of press-in pins that now project through circuit board 100. Circuit board 100 is resting on bearing elements 220 in the pressed-on state. In this state, that is to say, after circuit board 100 has been pressed onto press-in pins 210 by distance S, the until then essentially positive or nonpositive connection between press-in pins 210 and circuit board 100 may also be augmented by an integral component. To do so, a second fore (F2) is applied to the sonotrode. This second force (F2) may be approximately zero or even equal to zero. In particular, however, the sonotrode is acted upon by a second ultrasonic energy (|2), and the second ultrasonic energy (|2) is greater than the first ultrasonic energy (|1). Second ultrasonic energy (|2) may be considerably greater than first ultrasonic energy (|1), e.g., greater by at least 25%, and preferably greater by at least 50%. The amplitude and/or the frequency of the ultrasonic vibration may be increased for this purpose. Circuit board 100, induced to vibrations because of the application of second ultrasonic energy (|2), is now able to enter into a frictional welding connection with the surface of press-in pins 210 by way of the inner walls 132 of its contacting opening 130. Such a connection has an especially high holding power, an especially high electrical reliability and especially low electrical transition resistances. As described earlier, however, second ultrasonic energy (|2) may also be equal to first ultrasonic energy (|1) but second ultrasonic energy (|2) may also be lower than first ultrasonic energy (|1), for instance lower by at least 25%. At the same energy as first ultrasonic energy (|1), for instance, second ultrasonic energy (|2) may also differ from first ultrasonic energy (|1) by parameters of the ultrasonic vibration, e.g. by another frequency at a simultaneous other amplitude.

[0045] In FIGS. 2a and 2b, the method according to the present invention is shown analogously to FIGS. 1a and 1b. In contrast to FIGS. 1a and 1b, press-in component 200 is not developed as a type of plug connector or plug. Instead, a plurality of spacers 320 or bearing elements 320 are disposed on a carrier 300. Situated between bearing elements 320 are press-in components 200, such as sensors or integrated switching circuits, for instance in the form of SOIC housings 202 (SOIC=small outline integrated circuit), such that press-in pins 210 of press-in components 200 point away from carrier 300 and face circuit board 100. In accordance with the previous exemplary embodiment, corresponding contact openings 130 for each press-in pin 210 are situated in circuit board 100. In the same way, sonotrode 500, which is able to apply force and ultrasonic energy to circuit board 100, has been provided with recesses 510. Recesses 510 are once again situated at the locations where components 150 are provided on second side 104 of circuit board 100 or also in the particular locations where free ends 212 of press-in pins 200, which project through contacting openings 130 of circuit board after the press-in step, come to lie.

[0046] Press-in components 200, 202 are able to be temporarily fixed in place on carrier 300, for instance by vacuum. They may also be fixated on carrier 300 by a mechanical, easily closable and releasable mounting mechanism.

[0047] FIG. 2b illustrates the state in which the circuit board is pressed onto press-in pins 210 with the aid of sonotrode 500. In this exemplary embodiment too, an integral connection between contacting openings 130, or inner wall 132 of contacting opening 130, of circuit board 100 and press-in pins 210 is able to be achieved in that circuit board 100 is acted upon by a second ultrasonic energy (|2) by way of sonotrode 500. If sonotrode 500 is then removed and the holding mechanism of press-in components 200 on carrier 300 is released, circuit board 100 is completely fitted with press-in components 200 and may be removed from carrier 300.

[0048] In this way circuit boards 100 are able to be fitted with a multitude of press-in components 200, 202 (including an integral connection) in a single step by means of ultrasound-augmented press-in contacting or cold contacting technology, without thermal stressing of circuit board 100 or press-in components 200 to be fitted, as would be the case in reflow soldering, for instance.

[0049] FIG. 3 schematically illustrates the method for solderless electrical press-in contacting of electrically conductive press-in pins 210 in circuit boards 100. In a first step 710, a circuit board 100 is provided which has at least one contacting opening 130 that is routed essentially perpendicularly through circuit board 100, contacting opening 130 being suitable for press-in contacting. In a second step 720, a press-in component 200, 202 having at least one electrically conductive press-in pin 210 is provided. In a third step 730, a sonotrode 500 is made available for exerting a force and for applying ultrasonic energy. These three steps 710, 720, 730 may be carried out in a different sequence or at the same time.

[0050] Furthermore, following the first three steps, a press-in step 740 is provided. Here, the at least one press-in component 200 including its at least one press-in pin 210 is fixated during press-in step 740, particularly held firmly in place. In addition, in press-in step 740, a force (F), in particular a first force (F1), and an ultrasonic energy (|), in particular a first ultrasonic energy (|), are applied directly on circuit board 100 with the aid of sonotrode 500, in such a way that circuit board 100 is pressed onto the at least one press-in pin 210, not directly acted upon by sonotrode 500, of the at least one press-in component at the location of its at least one contact opening 130. In other words, ultrasonic energy (|) and force (F) are directly acting only circuit board 100. In press-in step 740, circuit board 100 may be pressed onto the at least one press-in pin 210 by a distance S. After distance S has been covered, a further step 750 may follow press-in step 740; the further step 750 could be viewed as a partial step of press-in step 740 subsequent to press-in step 740. In this further step 750, the sonotrode may exert a second force (F2) on circuit board 100, the second force (F2) being very low in comparison with first force (F1), e.g., amounting to maximally 10% of first force (F1) or even amounting to zero. In addition, sonotrode 500 is able to apply a second ultrasonic energy (|2) to circuit board 100 in the further step 750, second ultrasonic energy (|2) possibly being greater than first ultrasonic energy (|1). In particular, second ultrasonic energy (|2) may be of such magnitude that an integral friction-welded connection is achieved between the circuit board and the at least one press-in pin 201. As an alternative, second ultrasonic energy (|2) may of course also be of the same magnitude as first ultrasonic energy (|1) or it may be lower than first ultrasonic energy (|1).

[0051] For example, the method according to the present invention is suitable for use during the manufacture of products for which solderless electrical contacting is necessary in order to minimize the thermal stresses during the manufacturing process, for instance in the case of electrical or electronic control units for motor vehicles, for the contacting of circuit boards for computers, smartphones, tablet PCs and other consumer electronic devices or in the manufacture of network plugs for high-speed data transmissions.