DE3835027A1 - Method and device for the continuous production of multilayer circuits - Google Patents

Abstract

The invention relates to a method for the continuous production of multilayer circuits, in the case of which method a layer structure of multilayer laminate webs or multilayer laminates with prepreg webs is compressed in a twin-belt press to form a web of multilayer circuits, and in the case of which method the multilayer laminate web or multilayer laminates have fixing holes which are incorporated at the edges at regular intervals. Individual projections, which correspond to the fixing holes, are inserted into the fixing holes in the first multilayer laminate web or first multilayer laminate, and the further multilayer laminates or multilayer laminate webs are placed onto these projections so that the corresponding projections engage in the fixing holes in these further multilayer laminates or multilayer laminate webs and hold them fixed one above the other such that they are precisely fitted. The device which implements this method consists of a feed device for the individual corresponding projections into the fixing holes. The feed device is arranged in the vicinity of the unwinding roller for the first multilayer laminate web or in the vicinity of the laying device for the first multilayer laminate. The unwinding devices for the further multilayer laminate webs or the laying devices for the further multilayer laminates are arranged between the feed device and the twin-belt press.

Description

The invention relates to a process for the continuous production of Multilayer circuits according to the preamble of claim 1 and a device for performing the method according to the preamble of Claim 10.

Printed circuit boards have long been used in the electronics and electrical industry for the assembly of the components and their electrical connection under used each other. Serve as the starting material for such printed circuit boards copper-clad laminates. These copper-clad laminates consist of a laminate core, this on at least one surface Laminate core is an electrolytically deposited copper foil of high Purity level that is firmly connected to this surface. The Laminate core in turn is precondensed from individual layers resin-soaked carrier materials, the so-called Pre preg. This prepreg consists, for example, of glass fiber fabric, which with Epoxy resin is impregnated. The superimposed prepreg layers will be pressed under the action of heat and pressure with the copper foils, whereby the resin contained in the prepreg hardens and the copper-clad laminate is formed. In such a copper-clad laminate, the Laminate core as carrier and insulation material, the copper layer for Manufacture of conductor tracks. The production of these conductor tracks on the copper-clad laminate, i.e. the completion of the circuit board, is usually done by etching.

Due to the ever increasing integration density of the electronic Blocks with a variety of connections are used instead of the one multilayer circuit boards are increasingly used. These multilayer circuits consist of individual, the respective conductor printed circuit boards containing web patterns, which lie on top of one another with a precise fit, with each turn between two individual circuit boards insulating laminate. The individual circuit boards one Multilayer circuits are called multilayer layers. With these multilayer Circuits advantageously achieve greater freedom of movement and  Density in the conductor track routing, since the conductor tracks are crossing-free Leadership can be arranged on several levels.

DE-OS 33 07 057 is a continuous process and a pre direction for the production of multilayer circuits known. With this Processes are made on the edges of a copper-clad laminate sheet is continuously produced on a double belt press, after Ver let the double belt press introduce fixing holes that have a constant Distance from each other. The further processing of this copper cladding Laminate sheets for multilayer circuits are made in reference to these Fixing holes, two approaches are mentioned.

The first step is to use the copper-clad laminate sheet the fixing holes cut into individual plates, which were then separated by etching, drilling, and the like with the corresponding conductor track pattern, using the fixing holes as a reference for the position of the conductor pattern of the respective multilayer layer. In the In the second procedure, a conductor pattern is repeated in each case Reference to the fixing holes on the copper-clad laminate sheet placed so that one is a laminate web of regularly one behind the other ordered multilayer layers, the multilayer layer sheet.

The device for continuous manufacture shown in DE-DS 33 07 057 Positioning of multilayer circuits consists of a double belt press two endless pin chains that rotate synchronously over chain wheels through an edge of the press zone of the double belt press be performed. Unwinding units are in front of the double belt press Prepreg sheets arranged. The herge according to the first procedure Multilayer layers are created according to the desired structure of the Multilayer circuit using the fixing holes on the pin chain with a prepreg sheet between each two multilayer layers, which is unwound from rolls in the unwinding units. This package of multilayer layers with prepreg sheets in between  becomes a double belt press through the continuously advancing pin chain transported and in this under the influence of heat and pressure to Multilayer circuit pressed. The according to the second approach Multilayer ply webs are removed before the double belt press speaking of the structure of the multilayer circuit of rolls in unwind developed and attached to the pin chain using the fixing holes sets, in turn between two multilayer layers a prepreg web, which is also unwound from unwinding rolls, located. This package of multilayer layers with intervening Prepreg webs are trans from the pin chain towards the double belt press ported and pressed into a multilayer circuit. Behind The double belt press is a cross saw in which the individual Multilayer circuits from the multilayer circuit in turn Saw out the reference to the fixing holes.

The disadvantage of this known method is the complex control of the Synchronous running of the two pin chains and synchronism of the pin chains with the press belts of the double belt press. Low speed drop distinguish between the pin chains with each other or to the press belts lead to a shift of the individual multilayer layers or Multilayer layers and wrinkles, which ultimately the manufactured multilayer circuit becomes unusable. is still a exact parallel guidance of the pin chains to the press belts required, to avoid rejects. Transport and tax movements can swin pin chains and fluctuations in the preload of the Chain can cause a game between the chain links, causing the parallel guidance of the two pin chains is impaired. Furthermore is the manufacture of the pin chain within the required tight Tolerances, of a maximum of approx. 1/100 mm, for the production of multilayer Circuits are required, very difficult and therefore very expensive.

Starting from this prior art, the invention is based on the object reasons, the process for the continuous production of multilayer  Develop circuits so that the two pin chains are dispensed with can be and an easy way to fix the individual Multilayer layers or layer webs is reached.

The solution to this problem is given by the in the patent technical teaching described 1. A device for Implementation of the method according to the invention is carried out by the technical Teaching given in the characterizing part of claim 10.

The advantages that can be achieved with the invention are that the one individual multilayer layers or webs even before the double belt press and are immovably fixed regardless of the feed of the press belts. This eliminates the need for a complex control device Synchronization of the feed speed of the press belts with that the means for fixing the individual multilayer layers or layers. Movements of individual multilayer layers or layer webs are included Security is avoided and the committee is reduced. With the double band press for pressing the multilayer layers or layers a conventional double belt press without any modifications tion or additional equipment so that the to carry out the inventions device according to the inventive method also cheaper to manufacture is than the device known from the prior art.

A preferred embodiment of the invention is in the drawings shown and is described in more detail below. Show it

Fig. 1 shows an apparatus for the production of copper-clad laminates,

Fig. 2 is a multilayer sheet web with fixing holes in plan view,

Fig. 3 shows a multi-layer position with fixing holes in plan view,

Fig. 4 shows a device for the continuous manufacture of a web of multi-layer circuits from multilayer layer webs,

Fig. 5 shows a device for the continuous manufacture of multilayer circuits from multilayer sheets,

Fig. 6 shows schematically a section through a double belt press for Verpres solution of multilayer layer webs,

Fig. 7 shows a detail of the stacked, mutually-fixed multilayer layer webs in a perspective view;

Fig. 8 is a section along the line AA in Fig. 7 and

Fig. 9 shows a feed device for the corresponding projections in the fixing holes.

Schematically in Fig. 1 shown continuously operating Vorrich processing for the production of copper-clad laminates is known from DE-OS 33 07 057 and consists of a double band press 1, a punching device 2 for the fixing holes 17, unwinding units 3 and 4 with supply rolls 5 for the Prepreg and 6, 7 for the copper foil, a winding station 8 with rollers 9 for thin copper-clad laminate webs, moving scissors 10 and a control cabinet 13 with data display device 14 .

The prepreg webs for the laminate core, which are impregnated with pre-condensed resin, are drawn off from rolls 5 in the winding unit 3 and with copper foils which are pulled off rolls 6 , 7 in the unwinding unit 4 , so that a layered structure 15 is brought together the Pregpreg tracks lie between the two copper foil tracks. This layered structure 15 is pressed into the copper-clad laminate web 16 in the double belt press 1 under the action of heat and surface pressure. In a punching device 2 , fixing holes 17 , which are drawn in exaggeratedly large in FIG. 1 for illustrative reasons, are then introduced at regular intervals along the two edges of the copper-clad laminate web 16 . A computer in the control cabinet 13 , which is supplied with inputs by the operator via the data display device 14 , controls the entire production process and also the punching of the individual fixing holes 17 at a frequency which is dependent on the feed rate of the copper-clad laminate web 16 in the double belt press 1 . This ensures that the distances between the individual fixing holes 17 remain the same under all operating conditions of the device for producing copper-clad laminates, which is essential for the precise production of the multilayer circuits. It is also possible to measure the feed path of the copper-clad laminate web 16 and punch the fixing holes 17 synchronously with it. This allows distance tolerances of the fixing holes 17 of less than 0.01 mm to be achieved. In the punching device 2 there is at the same time a cooling and cleaning device in which the copper-clad laminate web 16 is cooled and the upper surface of which is cleaned. In the winding station 8 , the copper-clad laminate web 16 is wound up on rolls 9 if it is a thin, flexible copper-clad laminate web. Alternatively, the copper-clad laminate web 16 can be divided with the scissors 10 into copper-clad plates 11, which are stacked in pallets 12 .

These copper-clad laminate webs 16 , which can be wound on rolls 9 , or copper-clad plates 11 are then further processed into multilayer circuits. In Fig. 2 a top view is shown on such a copper-clad laminate web 16 with the inserted at the two edges in the punching device 2 fixing holes 17th The fixing holes 17 , the center points of which are at a constant distance from one another, are located along a hole edge 18 . With reference to these fixing holes 17 , etching resist areas 19 can then be defined for etching the desired conductor pattern. Can resist surfaces between each etching, if needed, additional fixing holes 20 are to be introduced. On the other hand, it may also be sufficient to make fixing holes 17 only on a single edge of the copper-clad laminate web 16 .

The desired conductor track pattern of a multilayer layer of the multilayer circuit is printed on each of these etching resist areas 19 , as is known, or applied using photographic means or the like. At the closing etching of the copper layer of the copper-clad laminate track 16 , the copper is etched away so far that only the conductor tracks remain. Advantageously, the same conductor pattern of a single multilayer layer is always produced on the copper-clad laminate path 16 on the etching resist surfaces 19 one behind the other, so that a corresponding multilayer layer path is obtained, on which the same conductor pattern is regularly arranged one behind the other. The further processing, such as drilling, milling, etc., of this multilayer layer located on the multilayer sheet also takes place in reference to the fixing holes 17 and 20 . Such a multilayer ply web is made for each multilayer ply of the multilayer circuit.

If the copper-clad laminate sheet 16 is already divided into individual copper-clad plates 11 , the respective conductor pattern of a multilayer layer is applied to the copper-clad plate 11 in reference to the fixing holes 17 in an etching resist surface 19 , as shown in FIG. 3. Subsequently, this copper-clad plate 11 is then further processed by etching, drilling, punching, milling and the like to form the corresponding multilayer layer, the fixing holes 17 serving as reference in each case. If necessary, further fixing holes 20 can also be arranged outside of the etching resist surfaces 19 on the two other edges of the plate 11 .

Of course, it is also possible the other way round, first the conductor track pattern on the copper-clad laminate sheet or on the copper-clad Apply plates and the fixing holes only afterwards in the copper laminated sheet or the copper-clad panels outside the To attach conductor structures. The fixation holes are then in reference  introduced to the respective conductor pattern.

As can be seen in more detail in FIG. 7 on the basis of a perspective section and in FIG. 8, the individual multilayer layer webs obtained as described are pressed to form a multilayer circuit or the individual multilayer layers to form a multilayer circuit the method according to the invention, individual projections 50 corresponding to the fixing holes 17 , 20 are inserted into the fixing holes 17 , 20 of the first multilayer sheet 51 or the first multilayer layer. The further multilayer layer webs 93 or the individual multilayer layers are placed on these projections in accordance with the desired sequence so that the projections 50 engage in the fixing holes 17 , 20 of the further multilayer layer webs 93 or multilayer layers. As a result, the multilayer layer webs 51 , 93 or multilayer layers are centered on one another. At least one prepreg sheet 94 is arranged in each case between the multilayer sheet layers 51 , 93 or multilayer layers. This layer structure 52 comprising multilayer layers 51 , 93 or multilayer layers and prepreg layers 94 is then exposed to pressure and heat and pressed to form multilayer circuits or multilayer circuits. The devices used for this are shown in more detail in FIGS. 4 and 5.

The apparatus shown schematically in Fig. 4 for the manufacture of a web of multi-layer circuits consisting of a continuously operating double belt press 21, a plurality arranged in front of this double belt press 21 unwinding units 22 to 27, a angeord Neten behind the double belt press 21 the cooling and cleaning means 28 and a crosscut saw 29 . The entire production sequence of the device shown in FIG. 4 is controlled by a computer in a control cabinet 30 . The operator inputs for the computer in the control cabinet 30 via a data display device 31 .

The double belt press 21 has, as can be seen in FIG. 6, two press belts 32 , 33 which are arranged one above the other in a press frame (not shown in the drawing for reasons of clarity) and which are endlessly guided over two deflection drums 34 , 35 and 36 , 37 , respectively. The press belts 32 , 33 are tensioned by means of hydraulic cylinders 38 . The deflection drums 34 , 35 , 36 , 37 are in turn rotatably mounted in bearing bridges 39 , 40 attached to the press frame (see FIG. 4). The structure of the press frame for such a double belt press is known per se and can be found, for example, in DE-OS 32 34 082. The lower press belt 32 is pulled out in front of the double belt press 21 by the lower bearing bridge 39 and the associated part 41 of the press frame at the inlet into the Doppelbandpres se 21 are extended in the horizontal direction and the deflection drum 37 for the press belt 32 is at the extreme end of this extension . Since the part of the press belt 32 located outside the double belt press 21 forms a conveyor belt for the multilayer ply and prepreg webs to be transported in the double belt press 21 .

As can be seen from FIG. 4, an unwinding unit 22 is attached in front of the deflection roller 37 , which includes a roller 42 for the first multilayer layer 51 and a roller 43 for the prepreg. The multilayer layer web 51 is continuously drawn off from the roll 42 and guided on the deflection drum 37 onto the press belt 32 . A prepreg web 94 , unwound from the roll 43 and having a slightly smaller width than the multilayer web 51 , is placed on this first multilayer web 51 so that the perforated edge 18 (see FIG. 2) of the prepreg web 94 is not covered. These webs 51 , 94 are transported further by the press belt 32 in the direction of the double belt press 21 . In the immediate vicinity of the unwinding unit 22 , a feed device 49 for the corresponding projections 50 is arranged on the lower press belt 32 . By means of this feed device 49 , the corresponding projections 50 are inserted into the fixing holes 17 , 20 of the moving, first multilayer layers 51 in such a way that the corresponding projections 50 extend upwards in the vertical direction, that is to say perpendicular to the surface of the press belt 32 or of the first multilayer ply 51 . Corresponding projections 50 are thus inserted behind the feed device 49 in all fixing holes 17 , 20 of the first multilayer layer web 51 .

This multilayer layer web 51 , provided with the corresponding projections 50 , with prepreg web 94 lying thereon, is guided along the second unwinding unit 23 with the press belt 32 . There, the second multilayer layer web 93 is unwound from a roll 44 and placed with the fixing holes 17 , 20 on the corresponding projections 50 of the first multilayer layer web 51 . Subsequently, a further prepreg web 94 , which is unwound from a roll 45 in the unwinding unit 24 , is placed on this multilayer web 93 . This is followed by further multilayer ply webs 93 which are unwound from rolls 46 in unwinding units 25 and separated by prepreg webs 94 which are drawn off from rolls 47 in unwinding units 26 . Finally, the last multilayer ply web 93 , which is unwound from a roll 48 in the unwinding unit 27 , is placed on the top prepreg layer. The number of these multilayer layers 93 and prepreg 94 of the layer structure 52 constructed in this way and thus the unwinding units 25 , 26 with rollers 46 , 47 is determined according to the desired structure of the multilayer circuit.

The centering of the individual multilayer layer sheets 51 , 93 with a precise fit one above the other is achieved with the aid of the corresponding projections 50 which engage in the corresponding fixing holes 17 on the hole edge 18 of the multilayer layer sheets or in the fixing holes 20 which may still be present between the individual etching resist surfaces 19 . It is necessary only at the beginning of the respective roller for the multi-layer ply sheet 93, it is applied in accordance with the conductor track pattern, the hole in reference to the fixer 17, 20, by means of the fixing holes 17, in register hang onto the underlying multilayer sheet web 20 , since the conductor patterns on each multilayer layer follow one after the other at regular intervals.

The web-shaped layer structure 52 , which is formed from the multilayer layer webs 51 , 93 separated by prepreg webs 94 and of which a section is shown in FIG. 7, then runs into the double belt press 21 . The inlet-side deflection drums 34 and 37 can be designed to be heatable, as is known, and thus preheat the multilayer layer webs 51 , 93 to avoid wrinkles. To clean the press belts 32 , 33 and possibly the outer multilayer sheet webs 51 , 93 of the multilayer circuit, cleaning devices 73 can be attached to the inlet-side deflection drums 34 and 37 , which remove dust and dirt from the press belts 32 , 33 . Such cleaning devices 73 are described in DE-OS 35 33 413.

In the double belt press 21 , the layer structure 52 is pressed between the two press belts 32 , 33 under the action of surface pressure and heat with simultaneous conveyance by the double belt press 21 . As can be seen in FIG. 6, in order to exert the surface pressure on the layer structure 52 , there are pressure plates 53 , 54 on the inside of the press belts 32 , 33 , of which a press pressure is transmitted to the press belt 32 , 33 via fluid or mechanical means. When pressure transmission with fluid means are in the pressure plate 53 annular self-contained lines 55 arranged, which touch the inside of the press belt 33 with a surface that slides along this surface. As a result, a pressure chamber 56 is formed between these seals 55 , the pressure plate 53 and the inside of the press belt 33 , in which a fluid medium is introduced under pressure. When pressure transfer with mechanical means be located on the pressure plate 54 stationary rollers 57 which transmit the pressure from the pressure plate 54 to the inside of the press belt 32 . Hydraulic cylinders 95 are used to position the pressure plate 54 against the press belt 32 .

The corresponding protruding projections 50 which engage in the fixing holes 17 , 20 on the layer structure 52 hold the multilayer sheet webs 51 , 93 immovably fixed even under the pressing pressure in the double belt press 21 , so that a shifting or rejection of individual multilayer sheet webs is closed and these fit exactly lie on top of each other. If desired, a cooling zone can subsequently be integrated in the double belt press 21 , in which the layer structure 52 is cooled under surface pressure. At the outlet of the double belt press 21 , the resin of the prepreg webs 94 is hardened and connects the individual webs of the layer structure 52 to one another to form a compact web 61 of multilayer circuits, in which the individual multilayer circuits are arranged one behind the other at regular intervals. As can be seen in FIG. 4, this web 61 of multilayer circuits is then passed through a cleaning and cooling device 28 in which the surfaces of the web 61 of multilayer circuits are cleaned with a solvent. Behind the cooling device 28 follows a cross saw 29 in which the individual multilayer circuits are cut out of the web 61 . The multilayer circuits can then be stacked on pallets for removal.

Instead of the upper and lower multilayer sheet, unetched copper foils can also be placed on the surfaces of the layer structure 52 , so that after the compression of the layer structure 52, the web 61 has a copper foil surface on the outer surfaces, which subsequently has the desired conductor pattern in reference to the fixing holes the top and bottom multilayer layer. The width of these copper foils is then expediently chosen such that it has approximately the width of the etching resist surfaces 19 (see FIG. 2) and extends between the two hole edges 18 . Since these copper foils have no fixing holes 17 , interference from the corresponding projections 50 is avoided. The conductor track patterns of the outer layers of the multilayer circuit can already be made behind the cooling device 28 in a processing station (not shown in FIG. 4) in reference to the fixing holes 17 . Alternatively, these conductor track patterns of the outer layers of the multilayer circuit can also only be produced after the track 61 has already been divided into individual multilayer circuits in the cross saw 29 . The edge of the hole 18 is expediently only trimmed when the outer layer of the multilayer circuit has been finished.

In Fig. 5 a further embodiment according to the invention before direction for the production of multilayer circuits shown a. The double belt press 62 is substantially identical to that of FIG. 4 or FIG. 6 constructed, the lower press belt is not preferred. To transport the multilayer layers, a separate conveyor belt 63 is arranged up to the entry into the double belt press 62 . This conveyor belt 63 is guided over two deflection rollers 64 , 65 , which are mounted in a frame 66 . Instead of multilayer layers, however, individual multilayer layers are now pressed to form a multilayer circuit. For this purpose, carrier plates 67 are attached to the frame 66 , on each of which there is a stack 68 of the same multilayer layers. The order of the stacks 68 corresponds to the desired order of the multilayer layers in the multilayer circuit. On the side of the conveyor belt 63 opposite the carrier plates 67 there are unwinding units 69 for rolls 70 of prepreg webs.

In the device shown, a copper foil is unwound from a roller 71 in an unwinding unit 72 and placed on the conveyor belt 63 in the region of the deflection roller 65 . On the deflection roller 65 of the conveyor belt 63 , a cleaning device 73 can be attached for cleaning the surface of the conveyor belt and the copper foil. On this copper foil, a prepreg web, which is unwound from a roll 74 in the unwind unit 72 , is arranged. The first multi-layer layer from the stack 68 is then placed on the prepreg web by means of a laying device 75 . The placement device 75 can consist, for example, of a movable vacuum suction plate. Immediately behind is a feed device 76 , with the help of which the corresponding projections 50 are inserted into the fixing holes 17 , 20 of the first multilayer layer.

A prepreg web, which is drawn off from a roll 70 in an unwinding unit 69 , is layered on the first multilayer layer. Subsequently, the next multilayer layer is placed on the prepreg web by means of a lay-up device 75 from the next stack 68 , the second multilayer layer being arranged through the fixing holes 17 , 20 centered above the first multilayer layer by the corresponding projections 50 in engage the fixing holes 17 , 20 of the second multilayer layer.

This is followed by further prepreg webs of rolls 70 from the unwinding units 69 alternating with further multilayer layers from the stacks 68 . On the top multilayer layer, in turn, a prepreg web and then a copper foil is placed on a roll 77 from an unwinding device 78 , which, if desired, can also be supplied via a cleaning device 73 . Such a cleaning device can also be attached to the lower press belt of the double belt press 62 .

Preferably, the copper foils and prepreg sheets have a width which corresponds approximately to the width of the etching resist area 19 (see FIG. 3), so that the copper foils and prepreg sheets can be arranged between the two hole edges 18 , thus introducing the corresponding protrusions 50 in the fixing holes 17 , 20 is not affected. This layered structure 79 , consisting of the multilayer layers, prepreg sheets and copper foils, is transported by the conveyor belt 63 into the double belt press 62 and pressed therein with surface pressure and heat to form a sheet 80 made of multilayer circuits, the corresponding projections 50 being the individual multilayers - Keep layers fixed to each other.

After the web 80 of multilayer circuits has left the double belt press 62 , the individual multilayer circuits are cut out by means of a cross-saw 29 , the fixing holes 17 , 20 or the corresponding projections 50 located in the fixing holes 17 , 20 again serving as a reference and the multilayer circuits are stacked on pallets for transport. In reference to the fixing holes 17 , 20 , the conductor pattern for the multilayer outer layers are then introduced into the copper foils located on the surfaces of the multilayer circuits. The fixing holes 17 , 20 of the edge 18 of the hole can then be trimmed if they are no longer needed.

Of course, direct the outer layers of the multilayer can circuit be selected in the embodiment of Fig. 5 as the uppermost and lowermost multilayer position, whereby the application of a untreated copper foil, which is only subsequently provided with the conductor pattern of the outer layer omitted.

Different embodiments for the corresponding projections 50 are shown in FIG. 8, in which a section along the line AA from FIG. 7 through the layer structure 52 and 79 in the edge region is shown. The reference numeral 81 denotes a rivet serving as a corresponding projection. The rivet 81 has the shape of a cylinder with a circular cross section, the diameter of which corresponds approximately to the diameter of the fixing hole 17 designed as a bore with a circular cross section. The rivet 81 protrudes somewhat from the top of the layer structure 52 .

The rivet 82 also has a cylindrical body. In this rivet 82 , the protruding part is formed as a head 85 on the upper side of the layer structure 52 . A particularly secure fixation of the multilayer layer webs or the multilayer layers is also achieved by this head 85 even under the pressing pressure in the double belt press 21 , 62 . The precisely fitting fixing of the multilayer layer sheets or multilayer layers is further improved with a rivet 83 which has two heads, one each on the bottom and top of the layer structure 52 , 79 .

The head 85 of the rivet 82 or ß3 can be molded in a particularly simple manner with the aid of a fixing tool 58 from the protruding end of an ordinary cylindrical rivet 81 . This fuser 58 is shown in more detail in Fig. 6 and is arranged near the inlet into the double belt press 21 . The layer structure 52 resting on the lower press belt 32 and entering the double belt press 21 is provided with cylindrical rivets 81 inserted in the fixing holes 17 , which form the corresponding projections 50 . At the entry into the double belt press 21 , the layer structure 52 passes through the fixing tool 58 , which consists of two parts 59 and 60 . Above the layered structure 52 , along the edge of the hole 18 , the wedge-shaped upper part 59 of the fixing device 58 is arranged, on which the parts of the rivets 81 projecting beyond the fixing holes 17 are bent and shaped into a rivet head 85 as in the case of the rivet 82 . The just-formed lower part 60 of the fixing tool 58 is arranged on the inside of the press belt 32 in the region of the hole edge 18 and supports the layer structure 52 during the fixing of the rivets 81 . If necessary, two wedge-shaped parts of a fixing tool can also act on the top and bottom of the rivets 81 , so that heads 85 are formed on both sides of the layer structure 52 as with the rivets 83 . The fixing tool 58 can be dispensed with if the inlet zone of the double belt press is tapered. Then, the heads 85 of the rivets 82, 83 formed under the molding pressure in the double belt press 21 to the layer structure 52nd

The corresponding projection 50 in the form of a hollow rivet 84 , which is also shown in FIG. 8, is particularly preferred. This hollow rivet 84 has the shape of a circular tube. To improve the fixation of the individual multilayer layer webs or multilayer layers, the ends of these hollow rivets 84 can in turn be provided with flanges 86 . To order flanges 86 can be made with a fixing tool 58 as described above. After compression of the layer 52 , 79 in the double belt press 21 , 62 to form a web 61 , 80 from multilayer circuits, this web 61 , 80 then has further fixing holes, which lead to the original fixing holes 17 of the multilayer web or multilayer layers are arranged concentrically and are formed by the cavity 87 of the hollow rivets 84 . Thus, the cavities 87 of the hollow rivets 84 in the path 61 , 80 in turn have a constant center-to-center distance and the individual conductor pattern of the multilayer circuit are also applied in reference to these cavities 87 of the hollow rivets 84 . If the surfaces of the web 61 , 80 from multilayer circuits still consist of unprocessed copper foils, the conductor pattern of the outer layers of the multilayer circuit can in turn be easily applied to the web 61 , 80 with reference to the cavities 87 . The other further processing of the multilayer circuit can also take place with reference to these cavities 87 . The edge of the hole 18 with the cavities 87 is only trimmed after the multilayer circuit has been completely processed.

The cross section of the fixing holes 17 , 20 , which are introduced by punching or the same in the multilayer sheet or in the multilayer, can have any shape. The corresponding projection 50 then has the shape of a prism, the base of which has the same shape as the cross-sectional area of the fixing hole. However, the simplest form for the fixing hole 17 , 20 is a circular cross section and the design of the corresponding projection 50 as a rivet 81 with a cylindrical shape, as has already been described in detail above.

The formation of the in Figs. 4 and 5 only schematically drawn feed means 49 and 76 for the corresponding protrusions 50 into the fixing holes 17, 20 is shown in detail in Fig. 9. The feed device 49 , 76 has a magazine 88 with one of the multilayer layer web 51 assigned opening 89 . The corresponding projections 50 are located in the magazine 88 and are pressed against the opening 89 by means of a slide 90 under spring pressure. A cylinder 91 is attached above the magazine 88 at the opening 89 , the plunger 92 of which can in each case eject a corresponding projection 50 through the opening 89 . The opening 89 can be closed in the unactuated state of the plunger 92 by a closure, not shown. The closure is then with the plunger 92 in operative connection so that it opens at an ejection movement of the plunger 92nd

If there is now a fixing hole 17 , 20 below the opening 89 , the cylinder 91 is pneumatically activated and the plunger 92 pushes the next corresponding projection out of the magazine 88 through the opening 89 and the corresponding projection 50 into the fixing hole 17 , 20 . The ejection movement can be triggered, for example, by a light barrier with which the position of the fixing hole 17 , 20 below the opening 89 is determined. As soon as the plunger 92 is retracted in the cylinder 91 , the next corresponding projection 50 is pushed by the slide 90 to the opening 89 , so that this next corresponding projection 50 can be inserted into the next fixing hole 17 , 20 of the continuously advancing multilayer sheet 51 .

Instead of the device described here for feeding such cor responding projections 50 into the fixing holes 17 , 20 , a robot can also be used for this, which takes the corresponding projections 50 from a magazine and inserts them into the fixing holes of the continuously advancing multilayer layer web 51 .

Claims (19)

1.Method for the continuous production of multilayer circuits which consist of a plurality of printed circuit boards which form a perfect fit and form the respective multilayer layer, with a laminate core therebetween, each of which corresponds to a multilayer layer in a known manner (for example by means of a photo resist / etching technology) are applied to a copper-clad laminate track one after the other at regular intervals, before or after, fixing holes in reference to the respective conductor track structure are introduced at regular intervals in the copper-clad laminate track outside of the conductor track structures, so that a multilayer layer track is created, the multilayer layer tracks be wound up on take-up rolls, then these take-up rolls are placed in unwinding units one behind the other with intermediate unwinding units for the prepreg webs, of which the Mult i layer-layer webs and the prepreg-webs are pulled off and placed on means engaging in the fixing holes, so that the multilayer-layer-webs with interposed prepreg-webs lie exactly one above the other to form a layer structure which represents the multilayer circuit arranged several times in succession, this layer is then transported to a double belt press and pressed there to form a multilayer circuit, characterized in that individual protrusions that correspond to the fixing holes are inserted into the fixing holes of the first multilayer layer web in front of the double belt press and then the further ones on these protrusions Multilayer sheets are placed so that the corresponding projections engage in the fixing holes of the other multilayer sheets. 2. Process for the continuous production of multilayer circuits, that of several, one on top of the other, the respective Multi circuit-layer-forming circuit boards with an intermediate one Laminate core exist, each of which corresponds to a multilayer layer the conductor track structures in a known manner (for example by photo resist / etching technology) on individual copper-clad laminate panels be brought before or after in reference to the respective conductor track Structure-related fixing holes in the copper at regular intervals laminated laminate panels introduced outside the conductor track structures are, so that a plate-shaped multilayer layer is formed, the Multilayer layers in lay-up facilities with intermediate layers winding units for the prepreg sheets are inserted, of which then alternately the multilayer layers are lifted off and the prepregs are removed and are placed on means engaging in the fixing holes, so that the multilayer layers lie precisely over one another intermediate prepreg webs to form a layered structure that the Multilayer circuit, this layered structure then transported by a double belt press and there to the multilayer circuit is pressed, characterized in that in the fixing holes of the first multilayer layer in front of the double belt press individual projections corresponding to the fixing holes are inserted and then the other multilayer layers on these projections be placed so that the corresponding projections in the fixing intervene in the holes of the other multilayer layers. 3. The method according to claim 1 or 2, characterized records that the corresponding projections in the Fixing holes are inserted that they over at least one of the outer Multilayer layers (webs) protrude and these protruding ends of the corresponding projections in front of the double belt press to achieve a fixation of the multilayer layers against each other.   4. The method according to claim 1 or 2, characterized records that the corresponding projections in the Fixing holes are inserted that they over at least one of the outer Multilayer layers (webs) protrude and these protruding ends of the corresponding projections by the pressure in the double belt press be flipped over in order to fix the multilayer layers against to reach each other. 5. The method according to any one of claims 1 to 4, characterized ge indicates that both the fixing holes and the corresponding projections have a circular cross section. 6. The method according to any one of claims 1 to 4, characterized ge indicates that the cross section of the fixing holes be a has a lovely shape and the corresponding projections have the shape of a prism with the same cross-section as the fixing holes. 7. The method according to claim 5, characterized in net that as corresponding projections cylindrical pins be used. 8. The method according to claim 7, characterized in net that rivets with heads used as corresponding projections will. 9. The method according to claim 8, characterized in net that used as rivets corresponding rivets will. 10. Apparatus for carrying out the method according to one of claims 1 or 3 to 9 with a two endless, in a press frame one above the other and each having two guide belts press belt having double belt press for pressing multilayer layers that have fixing holes outside the conductor track structures, whereby unwinding units for the multilayer layer webs present on a roll are arranged in front of the double belt press, with unwinding units for the rolls of the prepreg webs in between, and with means engaging in the fixing holes, which fit the multilayer layer webs to one another in a precisely fitting manner to form a layer structure Multilayer circuit arranged several times one behind the other and fixing the multilayer layers of this layer structure during the pressing in the double belt press, characterized in that in the fixing holes ( 17 , 20 ) the means consist of individual corresponding projections ( 50 ) which are arranged in the fixing holes ( 17 , 20 ) of the first multilayered web from a feed device ( 49 ) arranged in the vicinity of the unwinding roller ( 42 ) for the first multilayered web ( 51 ) ( 51 ) are inserted and the unwinding rollers ( 44 , 46 , 4 ß) for the further multilayer layer webs ( 93 ), in the fixing holes ( 17 , 20 ) of which the corresponding projections ( 50 ) engage, between the feed device ( 49 ) and the Double belt press ( 21 ) are arranged. 11. The device for carrying out the method according to one of claims 2 or 3 to 9 with a two endless, in a press frame arranged one above the other and guided over two guide belts each having double belt press for pressing plate-shaped multi-layer layers, the fixing holes outside the conductor track structures be sitting, in front of the double belt press laying devices for the multilayer layers in the form of plates with interposed unwinding units for the rolls of the prepreg webs and with means engaging in the fixing holes, which provide a precisely fitting layering of the multilayer layers to one Layer structure, which represents the multilayer circuit, and a fixing of the multilayer layers of this layer structure during the pressing in the double belt press, characterized in that the means engaging in the fixing holes ( 17 , 20 ) consist of individual correct There are sponing projections ( 50 ) which are inserted into the fixing holes ( 17 , 20 ) of the first multilayer layer ( 68 ) by a feed device ( 76 ) arranged in the vicinity of the placement device ( 75 ) for the first multilayer layer ( 68 ) and the laying devices ( 75 ) for the further multilayer layers ( 68 ), in the fixing holes ( 17 , 20 ) of which the corresponding projections ( 50 ) engage, are arranged between the feed device ( 76 ) and the double belt press ( 62 ). 12. The apparatus of claim 10 or 11, characterized in that between the unwinding roll ( 48 ) for the last multilayer layer web ( 93 ) or the lay-on device ( 75 ) for the last multilayer layer ( 68 ) and the double belt press ( 21 , 62 ) a fixing tool ( 58 ) is arranged for folding over the ends of the corresponding projections ( 50 ) which project beyond the outer multilayer layers or multilayer layer webs, in order to obtain further fixing of the multilayer layers (webs). 13. The apparatus according to claim 12, characterized in that the fixing tool ( 58 ) for folding over the outer multilayer layers (webs) projecting ends of the corresponding projections ( 50 ) from one on one side of the layer structure ( 52 , 79th ) arranged supporting lower part ( 60 ) and a wedge-shaped, on the other side of the layer structure ( 52 , 79 ) arranged upper part ( 59 ), so that the protruding ends of the corresponding projections ( 50 ) folded and at the same time heads ( 85 ) these corresponding projections ( 50 ) are formed during passage through the fixing tool ( 58 ). 14. The apparatus according to claim 12, characterized in that the press belts ( 32 , 33 ) in the double belt press ( 21 , 62 ) are arranged tapering in the inlet zone, so that the protruding ends of the corresponding projections ( 50 ) at the inlet in the double belt press ( 21 ) is folded over and at the same time heads ( 85 ) are molded onto these corresponding projections ( 50 ). 15. The device according to one of claims 10 to 14, characterized in that the feed device ( 49 , 76 ) has a magazine ( 88 ) for receiving the corresponding projections ( 50 ) and an opening ( 89 ) in the magazine ( 88 ) a plunger ( 92 ) is arranged to push the corresponding projections ( 50 ) out of the magazine ( 88 ) and into the fixing hole ( 17 , 20 ). 16. The apparatus according to claim 15, characterized in that the corresponding projections ( 50 ) in the magazine ( 88 ) by means of a spring-loaded slide ( 90 ) are pressed against the opening ( 89 ). 17. The apparatus of claim 15 or 16, characterized in that the plunger ( 92 ) by means of a cylinder ( 91 ) is actuated pneumatically. 18. Device according to one of claims 15 to 17, characterized in that the ejection movement of the plunger ( 92 ) is triggered by a light barrier which detects the position of the fixing hole ( 17 , 20 ) below the opening ( 89 ) of the magazine ( 88 ) . 19. Device according to one of claims 10 to 14, characterized in that the feed device ( 49 , 76 ) consists of a robot.