The invention relates to a method for producing a three-dimensional circuit having at least two superimposed substrate layers which comprise conductor paths and/or circuit elements.
DE-A-100 11 595 discloses a circuit arrangement in which a flexible printed circuit is connected to the circuit of a circuit carrier by means of a conductive adhesive. Compared with previously conventional solder connections, low production and assembly costs are obtained with this circuit arrangement.
DE-A-100 57 665 also describes an integrated circuit having at least two transistors which is in a stacked arrangement, for example a film being used as the substrate.
The object of the invention is further to reduce the production and assembly costs of a three-dimensional circuit. That object is achieved according to the invention by the features of claim 1.
The method according to the invention for producing a three-dimensional circuit having at least two superimposed, flexibly formed substrate layers comprising conductor paths and/or circuit elements composed of electrical functional materials is characterised by a combination of the following method steps:
Polymer materials are preferably used as the functional materials and are printed onto the flexible substrate layers. As a result, production is especially simple and inexpensive.
Depending on the application, an electrically insulating layer may be arranged between the substrate layers and may be composed of a solid substrate, especially of the sheet of material from which the substrate layers are also manufactured, or alternatively of a substance which is applied in liquid or gaseous form.
Furthermore, the substrate layers can be brought into electrical contact with each other by means of electrical contact connections between the conductor paths and/or circuit elements.
According to a further development of the invention, the production of electrical contact connections between the conductor paths and/or circuit elements can be effected by printing electrical functional materials. This can be effected in the case of two adjacent substrate layers by, for example, contacting directly opposing sites by a press contact, an opening being provided (for example by perforation) in an intermediate layer in the region of those two contact sites (see
Further advantages and developments of the invention are explained in more detail hereinafter by means of the description of some embodiments and the drawings.
In the drawings
a-6c are a schematic representation of the production of a contact,
The three-dimensional circuit shown schematically in
The substrate layers are manufactured from a continuous sheet of material, the substrate layers being separated from each other by a folding or bending edge 5 in the sheet of material and, after the conductor paths and/or circuit elements 4 have been applied, the sheet of material is folded about the folding or bending edge in such a manner that the two substrate layers are arranged one above the other.
Production is especially inexpensive when the electrical functional materials are applied to the flexible substrate layers by printing processes. In particular, letterpress, rotogravure or planographic processes are used.
The individual substrate layers 1, 2, 3 are connected securely to each other, it being possible to produce the secure connection, for example, by means of an adhesive, a laminating step, a perforating operation, by partial melting of the substrate layers or in some other manner.
Use is preferably made of conventional printing technology and the folding processes known in that context, both for the application of the conductor paths and/or circuit elements and for the folding operation.
The folding process takes place inline with the operation of printing the electronic circuit elements. This type of folding has the advantage that the printed structures are exactly defined and fixed in their spatial association on the substrate with the printing operation and, after folding, can be laid accurately on each other. It is therefore possible to lay several hundred layers exactly on top of each other. In this context, the term “inline” means that continuous assembly-line production is involved here.
The conduction distance between two vertically linked electronic components, such as, for example, two superimposed transistors, is therefore very small and is defined substantially by the thickness of the substrate layers. The thickness lies typically in the range of from 10 to 100 μm and is therefore more favourable than when links can be produced only in one plane. Any known process, such as, for example, newspaper folding, knife folding or buckle folding, comes into consideration as a folding process and, in particular, both longitudinal and transverse folds may be provided for.
As a rule, an insulating layer, which may be constituted either by an additional substrate layer or film layer (see
In the embodiment according to
The individual layers of the circuit must be connected to each other permanently, so that it is necessary to adhesively bond or paste each layer to the adjacent layer. This function can be combined with insulation, either a layer of film being introduced as the insulating paste film (reference sign 6 in
A three-dimensional circuit is possible, however, only when the individual substrate layers contained in the circuit stack can be connected to each other electrically. This can be effected for two adjacent substrate layers, for example, by contacting directly opposing sites 7,8 by a press contact, an opening 10 being provided in the insulating adhesive layer 9 in the region of those two contact sites 7,8 (see
In addition, an electrically conductive connection can also be produced by means of the folding or bending edge 5 (see
In order to produce the connection through a substrate layer, this being necessary for the circuit construction according to the invention, it is also possible, by means of a perforating device 14, to provide a perforation 13 in the substrate at the sites at which through-contacting is to take place (
An embodiment of a production process according to the invention is shown in
Expediently, the individual substrate layers are adhesively bonded to each other, the adhesive being applied in the printing process or during the folding process and optionally even taking on electrical functions, especially as an insulator, at the same time. Other substrate webs 20, for example provided with electronic functional components, may optionally also be introduced into the folding process so that the three-dimensional circuit 19 is formed from various webs placed together.
Number | Date | Country | Kind |
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10 2005 033 218.8 | Jul 2005 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2006/006788 | 7/11/2006 | WO | 00 | 1/7/2008 |