EP1309994A2

EP1309994A2 - Encapsulated organic-electronic component, method for producing the same and use thereof

Info

Publication number: EP1309994A2
Application number: EP01962659A
Authority: EP
Inventors: Wolfgang Clemens; Adolf Bernds; Henning Rost; Walter Fix
Original assignee: Siemens AG
Current assignee: PolyIC GmbH and Co KG
Priority date: 2000-08-18
Filing date: 2001-08-17
Publication date: 2003-05-14
Also published as: US20040026689A1; JP2004506985A; US7875975B2; WO2002015264A3; WO2002015264A2

Abstract

The invention relates to an electronic circuit (1), comprising electronic components (3) which consist especially of organic material. Said component(s) (3) are situated between at least two layers (2, 2') forming a barrier, and are protected against the influence of light and/or air and/or water by these layers. Electronic circuits constructed in this way enable (RFID) tags to be mass produced.

Description

Encapsulated organic-electronic component, process for its production and its use

The present invention relates to an electronic circuit made of organic material, in particular hermetically sealed against light and / or air and / or water, a method for its production and its use as a tag, sensor or the like.

Radio frequency ident tags (RFID) are currently being built with metallic coils and a silicon chip. They are used, for example, for logistics purposes, access controls or the like.

A simple encapsulation of an organic field effect transistor is known from DE 100 40 442.1.

Due to their relatively high production costs, they are not economical for mass applications such as electronic barcodes, for protection against plagiarism or as single-use items. RFID

Tags should be as passive as possible, i.e. without battery, work. They derive their energy from a coil, which is triggered by a reader in resonance. In this case, a memory is activated in an electronic chip of the tag and, for example, stored information, such as the sender and addressee in logistics applications, is read out.

The range between the reader and the day is determined by the power of the radiation from the reader, these are certain frequency ranges, such as 125 kHz or

13.56 MHz, as well as the size and quality of the coil or antenna of the tag. With passive tags, this range is typically less than 60 cm. The structure of the coil depends strongly on the carrier frequency used, for example, a coil is wound at a frequency of 125 kHz

Coil with usually several hundred turns used while a flat coil of about ten turns is used at a frequency of 13.56 MHz.

Organic electronic circuits can be manufactured very inexpensively. They are therefore suitable for building tags, which can therefore be used for the mass markets and as single-use products. One also thinks of electronic tickets, theft protection, baggage control or, for example, electronic stamps, electronic watermarks and much more.

Electronic circuits made of organic material in particular have two major disadvantages. On the one hand, the organic materials are very sensitive to environmental influences such as light, air and water and age relatively quickly under this influence. On the other hand, antennas manufactured in polymer technology or at all in printing technology are significantly worse than metallic antennas. They have a higher electrical resistance and a lower quality. This means that such electronic components and tags based on organic materials have a short lifespan and are only suitable for a very short range.

This aging problem is reasonably comparable for organic light-emitting diodes, so-called OLEDs. Glass is currently used here as a substrate and a glass plate is also glued over the components, so that a fairly good hermetic encapsulation is guaranteed. However, glass is not possible for the intended application within the scope of this invention for mechanical and cost reasons. Conventional organic substrates are permeable to light, air and water and are therefore not suitable. Metallized substrates, such as those used for example in the food packaging sector or in the airtight packaging of sensitive materials, are obviously also out of the question, especially with RFID tags, since the metal layer in the _S ubstrat prevents coupling of the coil to the reader. A Faraday cage or a metallic shield is created.

It is therefore an object of the present invention to provide a structure for an electronic circuit made of, in particular, organic material, in which the electronic circuit is hermetically shielded from light, air and water and therefore the aging problem does not occur. At the same time, the electronic circuit should be simple and inexpensive to manufacture, so that tags made from it can be used for mass markets and as disposable products and in particular can be combined with coils and antennas without metallic shielding occurring.

The present invention relates to an electronic circuit comprising electronic components made in particular from organic material, the component (s) being / being arranged between at least two layers (2, 2 ') forming a barrier and of these against the influence of light and / or Air and / or a liquid such as water are protected.

This hermetic sealing or encapsulation is achieved by using materials that form the largest possible barrier against environmental influences such as light, air and water. The circuit is arranged or built up on such a layer in a conventional manner, preferably using printing techniques. Another identical or functionally similar layer is arranged over the circuit by gluing or lamination, so that the organic circuit is encapsulated in a similarly good manner as described above for the OLEDs. It is only necessary to ensure that electrical contact points are freely accessible from the circuit.

The barrier layer preferably comprises at least one layer of plastic film, for example organic polymer such as polymer lyvinylphenol, polymethyl methacrylate, polysulfone, polycarbonate, polyether ketone, polyethylene terephthalate, polyethylene, polyimide or any mixture of these polymers.

According to a preferred embodiment of the invention, the upper barrier layer forms a cover layer of an organic field-effect transistor (OFETs), which can also be a type of substrate or flexible film substrate, in one embodiment a gate electrode being located on this substrate or carrier is applied to the components with the barrier layer. In order to then ensure a simple and precisely fitting adjustment of the cover layer, the gate electrode is applied to the upper substrate cover layer and preferably covered with an as yet uncrosslinked insulator. At the same time, a structure of substrate, drain and source electrode with a semiconducting layer and insulation layer is provided, in which the insulation layer is still not cross-linked.

Adjustment marks are again embedded in the two uncrosslinked insulation layers, so that the alignment marks allow simple and precise positioning of the superstructure (substrate with gate electrode and uncrosslinked isolator layer) on the substructure (substrate with source / drain electrode, semiconducting layer and uncrosslinked insulator layer) is possible.

The two superstructures are applied to one another, for example, by pressing on, pressing on, rolling on, etc.

To harden the insulation layer, the finished OFET is irradiated and / or annealed for a defined time.

Fixing rails, optical marks or crosses or the like are suitable as alignment marks. This creates an organic field-effect transistor on a substrate or a carrier, with the following structure: source / drain electrode on the substrate embedded in a semiconducting layer with an adjacent layer of insulating material, this layer is still uncrosslinked and then connected a gate electrode to which a cover layer is adjacent.

A method for producing such an OFET comprises the following steps: at least one source and one drain electrode are formed on a carrier, which are coated with a semiconducting layer, on which a layer with an uncrosslinked insulator is applied; - On a second substrate, a gate electrode with an overlying layer of uncrosslinked insulator is applied and the two carriers are then brought together so that the two uncrosslinked insulator layers come to lie on one another and then the crosslinking of the insulator is initiated.

The above-mentioned plastic films can either serve themselves as a barrier layer, by appropriate doping or crosslinking, or can be provided with a barrier layer that forms a shield. This separate barrier layer can be a metallic layer, for example, which is vapor-deposited or laminated onto the base film. Suitable metals are aluminum, copper or chrome. The plastic film usually has a thickness between 10 and 100 μm, preferably 30-60 μm. An applied metal layer is usually between 5 and 100 μm, preferably between 5 and 50 μm thick.

On the other hand, the barrier can also be formed by a non-metallic layer. This non-metallic material should be selected so that it is light and / or water and / or traps or absorbs oxygen. Suitable non-metallic coatings for forming a barrier against light, air and / or water are therefore, for example, layers of largely dense particles which are arranged to overlap as much as possible. Suitable materials for this purpose form graphite or inorganic oxides with a platelet structure.

In an advantageous embodiment of the present invention, the barrier layer used for the encapsulation can comprise barrier layers of the same or different types. In other words, the layer (s) forming the barrier can combine, for example, a metallic barrier coating and a non-metallic barrier coating. In general, the layer forming the barrier can therefore be a multi-layer system. A suitable structure consists, for example, of a polyethylene terephthalate film which is coated with aluminum, a polyethylene terephthalate film being laminated onto the aluminum coating again.

The film substrate can be transparent but also completely opaque. An opaque film even has the advantage that harmful effects of light in organic electronics are prevented in an optimal way.

The electronic circuit designed in accordance with the invention can thus include all components that are essential for a circuit. Preferably, however, the active components are mainly encapsulated. These are primarily the integrated circuit, transistors, diodes and in particular rectifier diodes or similar active components. The active components are preferably at least partially made of organic material.

The term “organic material” here encompasses all types of organic, organometallic and / or inorganic

Plastics that are called "plastics" in English. It deals with all types of fabrics Except for the semiconductors that form the classic diodes (germanium, silicon) and the typical metallic conductors. A restriction in the dogmatic sense to organic material as carbon-containing material is therefore not provided, but rather the widespread use of, for example, silicones , Furthermore, the term should not be subject to any restriction with regard to the molecular size, in particular to polymeric and / or oligomeric materials, but the use of "s all olecules" is also entirely possible.

The passive components such as resistors, capacitors, coils can also be included in the electronic circuit according to the invention. Only the sensitive components such as the organic integrated circuit itself can be contained just as well, and other parts, such as, for example, a rectifier diode, which can then still be produced using conventional silicon technology, can be located outside.

The electronic encapsulated circuit according to the invention can be used not only for tags but also wherever a metallized substrate is not an obstacle to use, for example also with sensors or other electronic components that can be implemented with organic electronics.

A particular advantage arises in the event that layer systems or film systems with metal layers are used for the film substrates. In this case, the metal layers can also be integrated into the corresponding circuit, for example by means of suitable structuring as electrical conductors or as passive components such as capacitors, coils, resistors.

The invention accordingly also relates to a method for producing an electronic circuit, comprising electronic components made in particular from organic material, with the following steps: Building a layer forming a barrier, arranging electronic components to form an electronic circuit on the barrier layer,

Creation of electrical conductor tracks to electrical contacts,

Application of at least one further barrier layer over at least partially the electronic components to seal them against light and / or air and / or water.

The electronic circuit can be as simple as

Tag or sensor can be formed and the inventive method can be used for this.

The invention is explained in more detail below with reference to the attached drawings, in which:

Fig. 1 shows an encapsulated electronic circuit according to the invention in section;

Fig. 2 shows the electronic circuit shown in Fig. 1 in a schematic plan view;

3a) to c) shows combinations of the electronic circuit according to the invention with a coil or a rod antenna;

Fig. 4 is a preferred embodiment of the combination of an electronic circuit according to the invention with a coil; and

5 is another preferred embodiment of such a combination.

6/7 show the production of an OFET from a substructure with a source / drain electrode and a semiconducting one

Layer and a superstructure with gate electrode, wherein the two structures are connected via an insulation layer.

1 shows an electronic circuit 1 according to the invention, which comprises electronic components 3. These electronic components 3 can be constructed entirely or partially from organic materials, that is to say conductive, semiconducting or non-conductive polymeric plastics. The electronic components 3 are arranged on a layer 2 forming a barrier, which in the embodiment shown is multi-layered. As such, the electronic components 3 or chips can be glued to the layer 2 or held stationary thereon in some other way. However, they can also be formed directly thereon by suitable printing processes.

The layer 2 itself is made up of three layers 4, 5 and 6 in the embodiment shown. The lowermost layer 4 is a plastic film suitable for the purposes of use, such as polyethylene, polyethylene terephthalate, polyimide or the like, flexible materials. The second layer 5 is designed as the actual barrier layer. This is preferably a metallic layer made of aluminum, copper or chromium, which is either laminated onto the layer 4 as a film or has been vapor-deposited thereon. As already mentioned, the barrier layer can also consist of a non-metallic substrate. Another layer 6 in the form of a plastic film is glued or laminated over the barrier layer 5.

Electrical contacts 8 are formed or arranged on this layer 2 in addition to the electronic components 3. They serve to later connect the electronic circuit 1 to, for example, a coil or antenna, that is to say to set up, for example, an RFID tag. The contacts 8 can consist of organic, conductive materials and can be applied, for example, to the film substrate in the printing process. the. Of course, metallic contacts, for example made of copper, can also be used. These contacts 8 are electrically conductively connected to predetermined ones of the electronic components 3 by lines 7.

A further barrier 2 ′, which has the same structure as the first layer 2, is hermetically sealed above the electronic components 3 and thus partly the lines 7. In the exemplary embodiment shown, it is again a multi-layer system consisting of two layers 4, 6 made of plastic film, between which a barrier layer 5 is arranged. The materials for these layers can be selected from the same ones that can be used for the further layer 2. For the manufacturing process, it is advantageous to either glue or laminate on this second upper and covering or encapsulating barrier layer as such. It can be seen that the individual electronic components are completely enclosed by layers 2 and 2 'and are therefore optimally shielded from environmental influences.

2 shows the structure of the electronic circuit 1 only in a top view, from which in particular the electrical connection to the contacts 8 lying outside the encapsulation is shown.

With reference to the following FIG. 3, it is now described how it is possible, despite the possibly metallized encapsulation of the electronic circuit 1, to have a greater range of an antenna, which is necessary for the construction of, for example, an RFID

Tags are required to achieve than with full integration of the organic electronics with the coil.

The electronics constructed in accordance with the invention are such that they can be attached as a kind of sticker with the exposed electrical contacts to a corresponding coil or antenna 9, 10. The respective ends of the coil (Fig. 3a) and 3b)) or a rod-shaped antenna (Fig. 3c)) can be connected to the encapsulated electronics by simply sticking. The whole set-up results in a functioning day.

With this construction, the electronics are separated from the coil. It is therefore possible to use a conventional metal antenna as a coil, which has a correspondingly high quality for the greatest possible range. Very large antennas can also be connected without the economic disadvantage that the more complex technology for producing the organic circuit is only required for a small part of the area.

A further step in production is also saved which is generally necessary in the case of flat coils, namely the connection of the corresponding coil ends 14, 15 in a further plane. It is possible here to use antennas in the packaging industry, for example, by means of inexpensive printing processes, and in a final step the stickers corresponding to the electronics described above can be stuck on.

It is advantageous here that the corresponding electrical

Connection areas are quite large to allow easy adjustment. If the connections are standardized, the application can only take place at a later stage. In retail, every company could stick their own tags. With this construction, even a metallized surface of the entire electronics is not disruptive for the RF connection of the antenna, since this lies above the coil turns and not in the area enclosed by the coil.

In the embodiments according to FIGS. 4 and 5, the electronic circuit 1 according to the invention is equipped with an antenna 9, 10 in a particularly efficient and cost-saving manner combined. An essential aspect here is that the “transponder circuit” is applied directly to the substrate of the antenna 9, 10. A homogeneously metallized plastic film 4, 5, for example again made of polyethylene, polyethylene terephthalate or polyimide with evaporated aluminum, is then used as the barrier layer 2. A coil is generated on the metal layer 5 by a structuring method. At locations where the actual circuit 3 is arranged, a metal layer is left, which then serves as a barrier or encapsulation. It is of course also conceivable to incorporate this metal layer directly into the circuit by appropriate structuring, for example as conductor tracks or as passive components. In this case, a multilayer system would be advantageous in which one layer can be used for encapsulation and one for use in the circuit.

The advantage of this structure is that the entire Ident Tag can be manufactured as an integrated system, which in particular reduces costs.

In FIG. 4, an antenna 9, 10 is formed on a barrier layer 2, which can be configured as described above, which antenna consists, for example, of a metal or a conductive polymer. In the interior of the antenna guide there is an electronic circuit 1, for example a silicon chip or a polymer chip, which is to be connected electronically at both ends 14, 15 of the antenna 9, 10. For this purpose, the corner 13 of the layer 2 represented by a dotted line is folded over in such a way that the end 14 of the antenna comes to rest on the contact surface 12. After folding, the electrical circuit 3 is connected to the antenna 9, 10 via the conductor tracks 7. In order to prevent a short circuit of the folded conductor track 7 with the antenna 9, 10, an insulation layer must be applied to the windings of the antenna 9, 10 before the folding. This insulation layer can also be used as an adhesive serve to permanently fix the folded corner 13. This type of connection can save the previously usual method step, namely the additional application of a structured conductor track.

According to FIG. 5, there is an antenna 9, 10 on layer 2, as in FIG. 4. An electronic circuit 3 is arranged outside the antenna 9, 10 in a corner 13 of layer 2. This corner 13 is then folded over so that the contact surface 8 comes to rest on the contacting surface 12 of the antenna 9, 10. In order to prevent a short circuit of the folded conductor track 7 with the antenna 9, 10, an insulation layer must be applied to the windings of the antenna 9, 10 before the folding. This insulation layer can also serve as an adhesive in order to permanently fix the folded corner 13.

The special feature of this embodiment is that the folding process on the one hand connects the electronic circuit 3 to the antenna 9, 10 and on the other hand encapsulates the electronic circuit 3, specifically by means of the substrate material, which must be suitably selected for this.

On the left in FIG. 6, the superstructure 16 and the substructure 17 can be seen, the arrows 18 indicating the direction in which the two superstructures are pressed against one another. The upper structure 16 comprises a substrate 19 such as a flexible PET film on which there is a thin layer 20 made of ITO (ITO = indium tin oxide) structured in the form of a gate electrode. The gate electrode 20 is embedded in a layer 21, for example of approximately 100 nm, of the uncrosslinked insulator material poly (4-hydroxystyrene) (PHS) with the crosslinker hexaethyloxyethylmelamine (HMMM). The insulator material is still not crosslinked in this layer, but contains the components necessary for crosslinking (crosslinker, ie HMMM and a catalyst, eg camphorsulfonic acid (CSA). The substructure 17 also has a substrate 19 with a structured layer 20 made of ITO, which forms the source and drain electrodes here. The source / drain electrodes are embedded in a semiconducting layer 22, for example made of poly (3-octylthiophene) P30T, as the active semiconductor material. An approximately 100 nm thick layer 21 of the insulator material PHS is likewise uncrosslinked on the semiconducting layer 22 and with the components necessary for crosslinking (crosslinker and catalyst). The superstructure 16 and the substructure 17 are pressed onto one another (FIG. 7) in such a way that the two layers 21 come to lie on one another and connect to one another on the surface. Adjustment marks are used to adjust the source / drain and the gate electrode one above the other in the desired manner. In a final step, the entire assembly is annealed at 130 ° C for one hour and thus fixed.

The separate generation of the gate electrode on a second substrate, presented for the first time in this embodiment, and its adjustment on the substrate / source, drain electrode / semiconductor / insulator structure facilitates the construction of OFETs in that no structuring of the upper electrode (source / Drain or gate, depending on the structure) by photolithography, in which the lower organic layers are attacked and / or dissolved. In addition, the OFET manufactured in this way is encapsulated and thus protected against mechanical damage and environmental influences.

The invention relates to an electronic circuit (1) comprising electronic components (3) made in particular of organic material, the component (s) being arranged between and against at least two layers (2, 2 *) forming a barrier the influence of light and / or air and / or water are protected. Electronic circuits constructed in this way enable the generation of RFID ident tags in particular as mass articles.

Claims

claims

1. Electronic circuit (1) comprising electronic components (3) made in particular of organic material, the component (s) being / are arranged between at least two layers (2, 2 ') forming a barrier and of these against the influence are protected from light and / or air and / or a liquid such as water.

2. Electronic circuit according to claim 1, characterized in that the barrier layer (2) u at least one layer of plastic film.

3. Electronic circuit according to claim 1 or 2, characterized in that it is an organic field-effect transistor, in which the following structure is realized: source / drain electrode on the first barrier-forming layer, a substrate, in a semiconducting layer embedded with an adjacent layer of insulating material, this layer still not being cross-linked and then connected to the uncross-linked insulation layer by a gate electrode to which the second layer forming a barrier, a cover layer, is connected.

4. Electronic circuit according to claim 3, wherein the

Cover layer is a substrate and / or support such as a flexible film.

5. Electronic circuit according to one of the preceding claims 3 or 4, in which adjustment marks are integrated in the still uncrosslinked insulation layer.

6. Electronic circuit according to one of the preceding claims, characterized in that the barrier layer (2) is a metallic and / or non-metallic layer.

7. Electronic circuit according to one of claims 1 to 6, characterized in that the metallic layer is selected from aluminum, copper or chrome.

8. Electronic circuit according to one of claims 1 to 7, characterized in that the components (3) are selected from active components.

9. Electronic circuit according to claim 8, characterized in that the active components are in particular an integrated circuit and / or a rectifier diode.

10. Electronic circuit according to one of claims 1 to 9, characterized in that the components (3) are selected from passive components.

11. Electronic circuit according to one of claims 1 to 10, characterized in that the passive components are in particular resistors, capacitors or coils.

12. Electronic circuit according to one of claims 1 to 11, characterized in that it comprises a coil arrangement (9, 10) or the like or is combined with such.

13. Electronic circuit according to one of the preceding claims, characterized in that it is conductively connected to external contacts (8).

14. A method for producing an electronic circuit comprising electronic components (3) made in particular of organic material, in particular according to one of claims 1 to 13, with the following steps:

Building up a layer (2) forming a barrier, i /

Arranging electronic components (3) to form an electronic circuit (1) on the barrier layer (2),

Creating electrical conductor tracks (7) to electrical contacts (8),

Applying a further layer (2 ') comprising at least one barrier layer (2) over the electronic components (3) to protect them against light and / or air and / or water.

15. The method according to claim 14, characterized in that the electronic circuit (1) is designed as a day.

16. The method according to claim 14, characterized in that the electronic circuit (1) is designed as a sensor.

17. A method for producing an electronic circuit according to one of claims 1 to 13, in which at least one source and one drain electrode are formed on a carrier, which are coated with a semiconducting layer, on which a layer with a non-crosslinked insulator is applied will (manufacture of the substructure); a gate electrode with an overlying layer of uncrosslinked insulator is applied to a second substrate (manufacture of the superstructure) and - the two supports are then brought together so that the two uncrosslinked insulator layers come to lie on one another and then the crosslinking of the insulator is initiated.

18.Use of an electronic circuit (1) according to one of claims 1 to 13 for the production of a tag.

9. Use of an electronic circuit (1) according to one of claims 1 to 13 for producing a sensor.