DE19618917C1 - Resin-sealed wired circuit board manufacturing method - Google Patents

Abstract

The circuit board manufacturing method uses a circuit board mould which is partially filled with an insulating resin mass (4) in which pre-fabricated contact elements (2,3) for surface-mounted components (SMD) (9,..12) are positioned at approximately the same height, with subsequent hardening of the resin mass. Wires are used to provide the required connections between the contact elements projecting from the resin mass, before filling the mould with a further resin mass layer (5), extending up to the ends of the contact elements, which is hardened before removal of the circuit board from the mould.

Description

The invention relates to a method and an apparatus for producing wire-written circuit boards or circuit boards.

The most common and most widespread methods in circuit board technology today rely on copper etching technology.

Furthermore, the board manufacturing process is known from the prior art so-called "wire writing". Here, the wires are made of electrically conductive Material as a connecting medium between the connection points of the board electronic components to be applied "wirewritten".

From DE-PS 32 47 344 is a method for applying preformed Conductor lines known on a carrier plate for producing conductor line patterns which is a process step preceding the wire writing of the production of a underlying plate provided with metallic pads.

These insulating material plates used as a circuit base have on their surface At every point where a conductor starts or ends a metal plate ends. The Metal plates used as pads are either in the prefabricated Poured base plate and thus create a conductive connection between the two Surfaces of the printed circuit board to be manufactured, or are only on the Conductor-bearing side of this. A disadvantage of this method is that the actual wire spelling the process of making a backing plate must precede the dimensionally and dimensionally stable with respect to later on this electronic components to be applied the electrically conductive contact elements owns, and so in succession during the transition to the wire deposit process an adaptation of the carrier plate dimensions to the wire writing device must be done. In this method, either only one or a maximum of both surfaces of the insulating plate carrying the circuit as Wiring levels available, which is reflected in the increased packing density of today's boards to the detriment.

In order to find contact surface for the connection of the wire you may have to find here in addition to the soldering area of the electronic components to be applied later Metal plates are unnecessarily larger, which in turn Packing density of the circuit board to be manufactured.

DE 25 08 545 describes a method for the mechanical laying of jumper wires known in which a multilayer arrangement of wiring levels in the Wire spelling is shown.  

Here, too, prefabricated insulating boards carrying conductor tracks come with the the disadvantage mentioned above. The subsequent one in the manufacturing process Layering of the individual carrier plates forces a registration device, which Universality of this procedure.

One method is to interconnect electronic micro-devices also known from DE-OS 23 26 861, which essentially refers to the Procedure according to DE 32 47 344 is based. Unlike this, here Circuit carrier created for electrical components that are housingless or one have a special housing shape adapted to this type of board.

In US 4 627 162 a method for producing a wire-written Printed circuit board, in which the contact surfaces for attaching the electronic component-bearing plate surface in a separate Process step with the layer carrying the wires of the conductor network in Is connected. This in turn creates the disadvantage of being complex dimensional adjustment of the differently prefabricated circuit carrier layers. In addition, here is used to apply the conductor network with Auxiliary device with support points attached in a fixed pitch Needle shape is formed, worked. The determination of a grid size limits the optional arrangement of the electronic to be installed on the circuit board Components. US Pat. No. 4,627,162 also contains the conductor tracks Levels either only on one or both surfaces of the circuit board and that too The resulting packing density of the electronic components becomes relative kept low.

From the "Manual of PCB technology" by Eugen G. Leuze Verlag in D-7968 Saulgau are two different discrete connection types, here called as "Multiwire" and "Microwire" connection techniques to the state of the art properly listed.

In "Multiwire" technology, the conductor wires are on one or both sides on one Adhesive-coated carrier board laid. A higher circuit density at Restriction to two circuit levels is reduced here by reducing the Wire diameter to 0.1 mm and smaller pitch of the wires and above through the use of power supply levels made of conductive material reached within the circuit board. Shielding is also used in this procedure  or cooling levels made of electrically conductive material in the circuit board brought to use inside.

A disadvantage of this method is the electrical contacting of the Board to be applied component connection surfaces. This contacting will by drilling the support plate and then coppering it and the reached the wire ends adjacent to the hole edges. In addition to Process engineering of the precise wire laying to be carried out Copper plating process.

"Microwire" technology is used to further increase the packing density electronic circuit reduces the wire diameter again. Furthermore power supply and cooling levels are also used here. After this through very precise wire description of the signal levels Bores for contacting the signal lines as well as the power supply and Ground planes made.

A disadvantage of this method is the simultaneous use of a very exact wire spelling and the technically complex copper plating of Component pads and holes.

The object of the invention is to provide a method and an apparatus for Making a wire-written circuit board or board with the help of simple and effective means.

The object on which the invention is based is achieved by a Manufacturing method of the type specified in claim 1, which according to the Features of claims 2 to 15 is advantageously developed.

A device according to the invention is characterized by the features of Claim 16 with the development of the device according to the Features of claim 17.

In particular, there is a method for producing wire-written printed circuit boards characterized by a partial filling of a curable insulating compound in a mold open at the top, the size of which corresponds to the specified circuit board shape, a positioning of prefabricated, essentially equally high, electrical conductive contact elements, curing the insulating compound, so that from the protruding hardened mass protruding contact elements are temporarily fixed Laying wires and making electrical connections between corresponding electrically conductive contact elements according to a predetermined  Circuit pattern, with the wires in case of own wire insulation any number of times, but limited by the PCB height and the used Wire diameter, can cross and even for non-insulated wires for one Wire crossing is an electrically non-conductive material, especially an electrically non-conductive one conductive film piece at least in the area of the wire crossing can, subsequent filling of the mold with curable insulating compound to the final height the contact elements and hardening of the mass in order to fix the wires and Contact elements, the mass being depressurized or by providing an end plate is introduced under pressure, and finally a removal of the hardened PCB from the mold.

Likewise, before the partial filling of the curable insulating compound electrically conductive contact elements are positioned. It can be provided that before positioning the contact elements for the purpose of provisional fixation inserting or applying an adhesive or adhesive layer into the casting mold, is sprayed in particular, with an additional on the adhesive or adhesive layer Wiring level can be formed. A fixation of positioned contact elements can also by magnetic connection, for example by magnetic on the pad adhesive elements.

Also can be provided to increase the packing density of the circuit board Printed circuit board made of several wiring levels cast in insulating material form, the number of wiring levels by the PCB end height and the wire diameter used is limited.

The contact elements are preferably positioned by setting the Contact elements via a 3- or connected to an electronic computer Multi-coordinate setting machine.

A particularly good fixation of wires results if after hardening an insulating layer and before laying or prescribing the wire Adhesive film is sprayed onto the surface of the insulating layer.

In particular, after laying the wires of a wiring level in the Carrier material is a prefabricated, the continuous cutouts for the Material layer containing contact elements, preferably made of metal, for the purpose Stiffness increase, electromagnetic shielding, cooling and / or for the purpose Power supply through subsequent connection with the contact elements, are poured or put on or glued, the recesses  preferably by machining or by laser with excess in advance from the Material layer are worked out.

Prior to final assembly of the circuit board, the top side of the circuit board and / or are preferred the underside of the printed circuit board is machined, in particular ground, to make desired exact final height of the board and the connection surfaces of the to optimize or clean electrically conductive contact elements.

The electrical contact elements used in a manufactured according to the invention Printed circuit boards have on the surface of the printed circuit board for mounting the various Components necessary, precisely adapted shape, and the amount of Contact elements correspond to those emerging from the printed circuit board surface on both sides Contact elements preferably the PCB end height or at only one side from the Circuit board emerging contact elements of a lower height than that PCB end height.

Because the dimension of the contact elements oriented at the component connections difficult for small component sizes on the ones used for wire writing The wire used here can be connected Contact elements have an enlarged wire connection area or likewise in In the case of small component sizes, they can be processed more advantageously Contact element modules are prefabricated.

A printed circuit board manufactured according to the invention can also have a corresponding Forming the mold into a three-dimensional, non-flat shape will.

During one between assigned contact elements using the wires completed connection can simultaneously the electrical conductivity of the Line connection are checked.

Are used instead of the contact elements cast into the circuit board in insulating material the connection wires of THD components or the connection surfaces of If SMD components are used, the contact elements can be omitted.

A device for carrying out the method for producing wire-written Printed circuit boards are characterized primarily by one with an electronic computer connected 3 or more coordinate setting machine for setting the contact elements in a desired circuit pattern, with the work surface of the typesetting machine  can form the bottom of the open-topped mold and the peripheral frame of the Casting mold can be formed by edge blocks, which in particular on the Work surface of the typesetting machine can be moved or moved, possibly by a hydraulic assistant.

The setting machine preferably has a 3-dimensional or multi-dimensionally adjustable Setting arm with a positioning bracket for positioning the electrically conductive Contact elements and / or with a guide clip for wire laying or Wire prescription, preferably after positioning the Positioning clip can be exchanged for the guide clip on the setting arm is.

A printed circuit board manufactured according to the invention is characterized above all with a first circuit board layer made of hardened insulating material top wire prescription and a second wire encasing the wire prescription and fixing circuit board layer made of hardened insulating material, the PCB layers of electrically conductive, positioned contact elements, top and / or penetrate flush below the PCB layers. The top and / or the underside of the circuit board are ground flat, the circuit board be formed from more than one wiring level cast in insulating material can. The contact elements are expediently metal sleeves and / or Metal blocks made of electrically conductive material, in particular electrical copper elements.

The invention therefore aims to keep all lines clearly within the PCB or, for example, with a high packing density, also just under the Lay surface. Vias and holes in manufacturing, with Except for the mechanical fastenings of special components.

There is a technological difference from the known methods mentioned above in that the prefabricated electrical contact elements simultaneously on the Completed board one for mounting the electronic components Form defined surfaces, at the same time a node in the Form a wiring network and, at the same height, that of the final board height corresponds to a plated-through hole from the top of the board to the bottom of the board represent, and this to form the wiring network within the board be contacted by wire prescription.

For components in the form of plug-in housings, metal tubes with a corresponding internal and outside diameter provided.  

For other elements, such as. B. SMD resistors, SMD ICs, etc. come Metal cuboid with corresponding surface dimensions for use.

The advantages of the invention compared to conventional circuit boards produced by wire-writing processes can be listed, inter alia, in the following points:
Since no wires are applied to the surfaces of the boards, the largest possible board surface is available for the assembly of the electronic components.

The wire prescription of the wires embedded within the board may be in one low precision because a subsequent drilling to contact the No wires.

The process of drilling connection openings for THD components and Holes for contacting laid wires are completely eliminated.

On the peripheral surfaces lying along the contact elements within the board this becomes a compared to only lying on the board surfaces Contact elements formed large connection area for the wires, which is higher Packing densities enabled.

Additional metallizations of the board surface at connection points of the electronic components are no longer necessary. The use is therefore no longer necessary an electroplating system, which is environmentally friendly.

The printed circuit board manufactured in the sense of the invention differs further Do not use one made in a conventional process Circuit board.

Mechanical assembly processes and printing techniques for Component designations can continue to be used.

It is also possible to produce three-dimensional, non-flat printed circuit boards.

The fixation of the electrically conductive contact elements can not only by Bonding agent order, but also e.g. B. done by magnets.  

If necessary, the component connections can also be inside the board lie, then individual contact elements are omitted.

The invention is described below using exemplary embodiments Described in more detail with reference to the accompanying drawings; show it:

Fig. 1 shows a finished printed circuit board or circuit board similar to FIG. 6, but with only an inner wiring layer,

Fig. 2 shows the illustrated in Fig. 1, Fig. 6 or Fig. 7 circuit board in a process step their preparation showing a the positioned electrically conductive contact elements, according to Fig. 8, fixing layer of insulating material,

Fig. 3 shows the arrangement according to FIG. 2 in a subsequent production step of the printed circuit board with additional display of wire connections between the electrically conductive contact elements,

Fig. 4 shows the arrangement according to Fig. 3 with additional crossover wire in a wiring plane,

Fig. 5 shows the arrangement of Fig. 3 during formation of a next wiring level,

Fig. 6 is a produced by the inventive process circuit board or board in a schematic perspective representation with electrically conducting contact elements according to Fig. 8, with two internal wiring planes,

Fig. 7 shows a finished printed circuit board similar to FIG. 1, with additionally introduced metal inlay for reinforcement, cooling, for an electromagnetic shield and / or for power supply by subsequent connection to said electrically conductive contact elements,

Fig. 8 shows examples of individual electrically conductive contact elements in the form of metal tubes and metal blocks in different heights and different cross-sectional shapes,

Fig. 9 Examples of contact elements that can individually in pre-assembled modules instead get to be set of electrically conductive contact elements are used;

Fig. 10 is a guide bracket of a Setzarm means connected to an electronic computer 3- or multi-coordinate setting machine in a schematic perspective drahtverschieblichen position during a wire laying (left) and a holding position of the wire during an electrical lead connection to an associated contact element (right), and

Fig. 11, the finished printed circuit board of Fig. 6 on the top side attached with additional representation of electronic components.

In order to produce a wire-written circuit board or circuit board 1 according to FIG. 1 using electrically conductive contact elements 2 , 3 according to FIG. 8 in a composite construction, the following six process steps are basically necessary:

• - Filling a curable insulating compound into the casting mold for the purpose of forming a first electrically insulating circuit board layer 4, for example according to FIG. 2.
• - Positioning of essentially the same height, electrically conductive, prefabricated contact elements 2, 3, for example according to FIG. 2, in a mold (not shown) open at the top with a peripheral frame corresponding to a predetermined shape of a printed circuit board 1 to be manufactured, the positioning of the contact elements 2 , 3 is preferably carried out via a 3-coordinate or multi-coordinate setting machine (not illustrated) connected to an electronic computer.
• - Hardening of the insulating compound for the purpose of fixing the electrically conductive contact elements protruding from the first circuit board layer 4, for example according to FIG. 2.
• - Laying the wires 8 according to FIG. 3 between assigned contact elements 2 , 3 on the first printed circuit board layer 4 with establishing an electrical line connection 10 , 11 between the assigned contact elements in accordance with the predetermined circuit pattern.
• - Further filling of the casting mold with curable insulating compound up to the desired circuit board final height in the area of the final height of the electrical contact elements in order to form a second, electrically insulating circuit board layer 5 according to FIG. 1 and fixing the laid wires 8 and further fixing the electrical contact elements.
• - Removing the hardened circuit board 1 according to FIG. 1 from the mold.

A production of a printed circuit board 1 according to the invention can be explained by way of example in several work steps:
The electronic circuit is designed and designed on a CAD station.

Partial filling of a curable insulating compound in a mold open at the top to form an insulating layer 4 according to FIG. 1. Component data, spacing of the connecting pins of THD components, SMD connecting surfaces 16 , 17 according to FIG. 8 etc. go from a computer to a numerical one Controlled setting machine, which inserts the corresponding, prefabricated, electrically conductive contact elements 2 , 3 into the casting mold filled with a first circuit board layer 4 . To fix the contact elements, the insulating layer 4 is cured according to FIG. 2.

Alternatively, it would be possible to insert an adhesive film into the casting mold (not shown) as the first working step for the provisional fixation of the contact elements, to place the electrically conductive contact elements to size on the base plate of the casting mold as a second working step and as a third working step the first insulating material layer 4 according to FIG. 1 partially fill in and harden it to fix the contact elements. The adhesive layer can also be equipped with a wiring level.

Moreover, it is expedient, after curing of the first insulating spray the electrical contact elements fixing the circuit board layer 4, an electrically non-conductive adhesive film on this layer 4 to the adjustment of the wire to be laid.

For the actual wire laying or wire prescription, a preferably insulated wire 8 (preferably provided with a lacquer layer), preferably electric copper wire, is used.

The beginning of the wire is inserted, for example, into a guide bracket 9 shown schematically in FIG. 10 and held in a holding position of the guide bracket, for example according to FIG. 10, on the right, and is placed on the electrically conductive contact elements 2 , 3 to be connected and then electrically conductively connected, in particular welded, soldered or glued.

If a line connection 10 , 11 is made with a contact element 2 or 3 , the guide clip 9 is shown in a wire-displaceable laying position in FIG. 10, left, released, and then the wire is moved by means of the guide clip 9 on the path specified by the electronic computer the guide clip is laid along the path (it being possible for crossings of wires 12 according to FIG. 4 to be provided, and a non-insulated wire can also be used if the wire runs without crossing).

If a wire 8 is laid up to its wire end, the wire end held there by means of the guide clip 9 in the holding position, for example according to FIG. 10, on the right, is also laterally applied to the electrically conductive contact element to be connected and electrically conductively connected, in particular welded, soldered or glued in place.

During the establishment of the connection, the electrical conductivity can also simultaneously the line connection can be checked.

The remaining space between the first insulating layer 4 and the full thickness of the circuit board can now be filled by further filling the casting mold with curable insulating compound up to the final height of the contact elements either without pressure or by providing an end plate under pressure. The subsequent hardening of the resulting wiring level 5 cast in the insulating material also serves to further fix the contact elements and to fix the wires lying inside the circuit board.

In the case of printed circuit boards with a high packing density, the steps of applying the adhesive film, describing the wire, making connections and filling with curable insulating compound are often possible, so that there is a multiple layering of the wiring levels, for example shown in FIG. 6 with the first wiring level 5 and the second wiring level 6 .

An illustration of an on a cast-in insulating material and cured wiring layer 5, for example, the second wire prescription shown in FIG. 5.

In addition, after laying the wires of a wiring level 5 or 6 in the insulating material, a prefabricated material layer 19 , which contains the continuous recesses for the contact elements, for example according to FIG. 7, for the purpose of increasing rigidity, electromagnetic shielding, cooling and / or for the purpose of power supply by subsequent connection to the Contact elements, poured or placed or glued.

The electrically conductive contact elements to be used should be made of Metal, preferably electrical copper, is the same height as that to be manufactured Printed circuit board adapted and own, preferably on the from the circuit board emerging surface, manufactured cross-section to the connecting surface of the electronic components defined form.

They can be metal sleeves 2 according to FIGS. 8a to 8c in various embodiments, which have defined solder connection surfaces 16 , 17 for component mounting and defined openings 15 for receiving the component pins of THD components.

They can be metal cuboids 3 according to FIGS. 8d to 8f in various embodiments, which have defined solder connection areas 16 , 17 for contacting SMD component pins and, for example, for better wire contacting with fine-pitch SMD components have an enlarged connection area 18 according to FIG. 8 .

The electrical contact elements can, in order to accelerate the process of setting by means of a numerically controlled setting machine, consist of prefabricated modules 20 , 21, for example shown in Fig. 9a or 9b, which consist of the aforementioned electrically conductive contact elements 3 or 2 with intermediate, made of insulating material existing spacing spaces are kept in their shape, and are thus adapted to standardized, electronic components and their connecting pins or connecting surfaces in a dimensionally stable form.

After the last wiring level 5 in FIG. 1 or FIG. 7 or wiring level 6 in accordance with FIG. 6 has been cast in the insulating material, it is removed from the casting mold and preferably the top 13 and the bottom 14 of the printed circuit board are ground flat in order to adapt them to the dimensions to create electronic or mechanical components to be assembled later.

The further use differs from that produced in the sense of the invention Printed circuit board not from one made in a conventional process Printed circuit board, however, it is also possible to apply the method according to the invention 3-dimensional, non-flat circuit carriers to use and thus a different type Manufacture form of use of the circuit board in a simple manner.

Claims (18)

1. A method for producing wire-written circuit boards ( 1 ), characterized by

• - partial filling of a curable insulating compound ( 4 ) into a mold open at the top, the size of which corresponds to the specified circuit board shape,
• - Positioning of prefabricated, essentially equally high, electrically conductive contact elements ( 2 , 3 ) for component fixing,
• Curing the insulating compound ( 4 ) so that the contact elements ( 2 , 3 ) protruding from the hardened compound are temporarily fixed,
• - Laying wires ( 8 ) and making electrical connections ( 10 , 11 ) between corresponding contact elements ( 2 , 3 ), the wires ( 8 ) in the case of their own wire insulation as often as desired, but limited by the PCB end height and used wire diameter, can cross and in the case of even non-insulated wires for a wire crossing ( 12 ) an electrically non-conductive material, in particular an electrically non-conductive piece of film, can be arranged at least in the area of the wire crossing ( 12 ),
• - Filling the casting mold with curable insulating compound ( 5 ) to the final height of the contact elements ( 2 , 3 ) and curing the compound (fixing the wires ( 8 ) and the contact elements ( 2 , 3 )), the mass
• - depressurized or
• - by providing an end plate under pressure

is introduced

• - Remove the hardened circuit board ( 1 ) from the mold.

2. The method according to claim 1, characterized in that before the partial filling of the curable insulating compound ( 4 ), the electrically conductive contact elements ( 2 , 3 ) are positioned and optionally fixed. 3. The method according to claim 2, characterized in that prior to fixing the contact elements ( 2 , 3 ) for the purpose of provisionally fixing the same, an adhesive or adhesive layer is inserted / applied, in particular sprayed, into the casting mold, being on the adhesive or adhesive layer a wiring level can be formed. 4. The method according to any one of claims 2, characterized in that the contact elements ( 2 , 3 ) are fixed by means of magnets. 5. The method according to any one of claims 1 to 4, characterized in that the circuit board from more than one cast in insulating material wiring level ( 5 , 6 ), the number of which is limited by the height of the circuit board and the wire diameter used, is formed. 6. The method according to any one of claims 1 to 5, characterized in that the positioning of the contact elements ( 2 , 3 ) is carried out by setting the contact elements via a 3 or more coordinate setting machine connected to an electronic computer. 7. The method according to any one of claims 1 to 6, characterized in that after the hardening of the first insulating layer ( 4 ) or a wiring level cast in insulating material ( 5 ) and before the wire laying or wire prescription, an adhesive film for the purpose of adjusting the wire ( 8 ) is sprayed on this. 8. The method according to any one of claims 1 to 7, characterized in that after laying the wires ( 8 ) a wiring level in the carrier material ( 5 , 6 ) a prefabricated, the continuous recesses for the contact elements ( 2 , 3 ) containing material layer ( 19 ), preferably made of metal, for the purpose of increasing stiffness, electromagnetic shielding, cooling and / or for the purpose of power supply by subsequent connection to the contact elements ( 2 , 3 ), poured or placed or glued, the recesses preferably by machining or by laser with oversize be worked out from the material layer beforehand. 9. The method according to any one of claims 1 to 8, characterized in that the circuit board top ( 13 ) and / or the circuit board underside ( 14 ) is machined, in particular ground. 10. The method according to any one of claims 1 to 9, characterized in that the contact element surfaces ( 16 , 17 ) emerging on the printed circuit board surfaces ( 13 , 14 ) are formed in a form necessary for mounting the various components. 11. The method according to any one of claims 1 to 10, characterized in that the contact elements are arranged such that the height of the contact elements ( 2 , 3 ) emerging from the printed circuit board surface ( 13 , 14 ) on both sides corresponds to the end height of the printed circuit board or only from one side the printed circuit board surface emerging contact elements corresponds to a smaller than that of the PCB end height. 12. The method according to any one of claims 1 to 11, characterized in that the contact elements ( 2 , 3 ) either with small dimensions with an enlarged connection surface ( 18 ) for the wires ( 8 ) or already in advance in contact element modules ( 20 , 21st ) are prefabricated. 13. The method according to any one of claims 1 to 12, characterized, that by appropriate training of the mold also three-dimensional, not flat circuit boards are manufactured. 14. The method according to any one of claims 1 to 13, characterized in that the electrical conductivity of the line connection is simultaneously checked during an established between connection contact elements ( 2 , 3 ) with the aid of the wires ( 8 ). 15. The method according to any one of claims 1 to 14, characterized in that the connecting wires of the THD components ( 25 , 26 ) or the connection surfaces of the SMD components ( 23 , 24 ) are formed as contact elements. 16. An apparatus for performing the method for producing wire-written circuit boards according to one of claims 1 to 15, characterized in that a 3 or more coordinate setting machine connected to an electronic computer for positioning the contact elements ( 2 , 3 ) in a desired circuit pattern is provided, the working surface of the setting machine forming the bottom of the mold open at the top and the peripheral frame of the casting mold can be formed by edge blocks, which in particular can be displaceable or displaceable on the working surface of the setting machine. 17. The apparatus according to claim 16, characterized in that the 3- or multi-coordinate setting machine has a setting arm with a positioning bracket for positioning the contact elements ( 2 , 3 ) and / or with a guide bracket ( 9 ) for wire laying or wire prescription, the positioning bracket preferably being interchangeable with the guide bracket ( 9 ) on the setting arm after positioning.