DE102007063910B3 - Protective encapsulation for at least one electronic component and electronic component - Google Patents

Abstract

Protective encapsulation (10) for at least one electronic component (20), with a flat encapsulation element (1) which has a structured surface (2) with at least one cavity (8) on at least one side, with a drying agent (5) in the encapsulation element (1) is pressed, whereby the at least one cavity (8) is formed, and wherein the material of the drying agent (5) has a higher melting point than the material of the encapsulation element (1), and wherein the drying agent (5) by the action of heat in the at least one Cavity (8) is sintered.

Description

The invention relates to a protective encapsulation provided with at least one cavity for at least one electronic component, in particular for an electro-optical or optoelectronic component such as an organic light emitting diode (OLED). Such and other electronic components are first formed on a carrier substrate and later covered with a protective encapsulation in order to prevent the penetration of contaminants from the ambient air, in particular moisture. Depending on the type of electronic component, the carrier substrate can remain wholly or partially on the electronic component or can be completely or partially removed. For example, semiconductor substrates (including binary, ternary or quaternary substrates, in particular III-V substrates) can be used as the carrier substrate. For optoelectronic or electrooptical applications, in particular transparent substrates (in the visible or another wavelength range) can be used. The side of the electronic component facing away from the carrier substrate and the lateral periphery of the component usually have to be shielded from external influences. For example, in the case of organic light-emitting diodes, moisture penetrating the component can impair the generation of light and lead to premature aging. However, the efficiency and functionality of other electronic components are also endangered by the ingress of moisture or other foreign substances. All of this leads to a loss of quality and even premature failure during the intended service life.

Encapsulation is usually provided for protection in the exposed areas of the respective component. This essentially consists of a pre-processed plate, which is structured on one side, made of, for example, a glass, a metal or a ceramic. The pre-structured plate has (depending on the design and number of electronic components) on the side facing the component one or more cavities, that is to say cutouts. The recesses or cavities in the pre-structured encapsulation element serve to hold a desiccant, that is to say a desiccant, and are intended to keep moisture (possibly also other impurities) away from the electronic component during the service life of the electronic component. The drying agent can be formed from a physisorbent or a chemisorbent material, for example.

The cavities can be arranged, for example, where electronic components are arranged (in a comparable position on the carrier substrate). The cavity and the drying agent arranged therein could, however, also be provided in a circumferential surface area of the encapsulation element which, after the encapsulation element has been joined to the carrier substrate, surrounds the component in a ring and, in particular, binds moisture that has penetrated through the adhesive bond between the encapsulation element and carrier substrate.

The production of the encapsulation element conventionally involves a large number of production steps and also a large number of additional work steps during transport and packaging. In particular, conventionally, to produce the protective encapsulation, a glass plate or another flat encapsulation element must first be structured (to be precise before the desiccant is introduced) in order to form the cavities. For this purpose, for example, a mask is applied to the as yet unstructured encapsulation element (for example a glass plate) and the encapsulation element is structured, for example, by sandblasting or by etching. The structured encapsulation element is then cleaned, provided with a protective film and finally packaged for shipping. The drying agent is produced elsewhere and packaged in a manner that is suitable for application to the glass plate or introduction into the cavities. In packaged form, the desiccant is also packaged ready for dispatch and, if necessary, activated beforehand in order to drive out any moisture that has remained due to the manufacturing process (especially in the case of physisorbent desiccants).

The encapsulation element and the packaged desiccant are unpacked after shipping under clean room conditions and applied to one another, creating the protective encapsulation. This is then applied to the carrier substrate provided with the at least one electronic component. In particular, the protective encapsulation is glued onto the carrier substrate.

Due to the large number of work steps involved in manufacturing the flat encapsulation element (which encloses the back of the electronic component), the desiccant and the separate shipping and re-unpacking during assembly, a high expenditure of work, time and money has so far been incurred.

The pamphlet U.S. 5,189,405 A relates to an OLED component in which a drying agent film is glued onto an OLED layer sequence.

The document US 2002/057 565 A1 describes an OLED component in which a desiccant is produced in a cover pan or is located above a sequence of OLED layers, separated by a membrane.

From the pamphlet US 7 083 866 B2 OLED components are known in which a drying agent is applied to the inside of a cover.

According to the document US 2003/0 091 858 A1, a drying agent is located outside a cavity for an OLED layer sequence.

The pamphlet DE 101 47 648 B4 describes a method for forming openings in a sheet of glass.

The pamphlet WO 2006/117710 A1 relates to an LED light source with LED chips in recesses in a housing.

It is the object of the present invention to provide a protective encapsulation which can be produced efficiently.

According to the invention, this object is achieved by a protective encapsulation according to claim 1 and by an electronic component with such according to claim 10.

• - Aufbringen eines flächigen Verkapselungselements und eines Trocknungsmittels aufeinander, wodurch das Trocknungsmittel an vorgegebenen Flächenbereichen einer Oberfläche des Verkapselungselements anliegt, und
• - Durchführen eines Formgebungsschrittes unter Wärmeeinwirkung, wodurch in der Oberfläche des flächigen Verkapselungselements zumindest eine Kavität ausgebildet wird, die das Trocknungsmittel aufnimmt.

A method is used to produce the protective encapsulation, which comprises the following:

• Applying a flat encapsulation element and a desiccant to one another, as a result of which the desiccant rests against predetermined surface areas of a surface of the encapsulation element, and
• - Carrying out a shaping step under the action of heat, as a result of which at least one cavity is formed in the surface of the flat encapsulation element, which cavity receives the desiccant.

According to the invention, the application of the drying agent to the flat encapsulation element is linked to the structuring of the encapsulation element. In particular, according to the invention, the desiccant is not introduced into prefabricated cavities of an already pre-structured encapsulation element, but the encapsulation element itself is only structured during or after the desiccant has been applied. This is unusual because the desiccant, when applied to the encapsulation element, covers precisely those areas that should actually be structured, but are no longer accessible to sandblasting or chemical etching due to the desiccant lying on top.

According to the invention, the structuring is not carried out, as is conventional, by a chemical or other destructive external effect, but by reshaping the encapsulation element, which is subjected to a heat effect for this purpose, which results in a spatial deformation of the material of the encapsulation element (in the simplest case an initially unstructured glass plate) made possible or at least facilitated. In the heated state, according to the invention, the encapsulation element is shaped in which the desiccant partially displaces the material of the encapsulation element and it is precisely because of this that the cavities are created. However, the cavities can also be formed in such a way that the material of the encapsulation element is forced into free spaces between different areas of a desiccant, for example by liquefaction and / or by the action of pressure in the heated state.

Compared to conventional manufacturing processes, the cavities are only created when the desiccant is introduced into the material of the encapsulation element. In addition, as outlined above, the desiccant itself is used to displace material or shape the encapsulation element. The protective encapsulation is then finished as a whole and can be shipped or mounted as a whole, for example on a carrier substrate with one or more electronic components.

If necessary, the action of heat can be used to reshape the flat carrier element at the same time to thermally activate the desiccant (that is, to drive out any moisture that is still present during production and thus to make the desiccant actively moisture-binding). The action of heat can also be used to physically reshape the drying agent, for example to sinter it.

It is preferably provided that the surface of the encapsulation element is a planar surface which is deformed under the action of heat in the shaping step. In contrast to conventional manufacturing processes, unstructured, completely flat plates made of, for example, glass, metal or ceramic (or any other moisture-impermeable material) can be used for the first time without the need for complex structuring steps by chemical etching or sandblasting. Rather, the initially flat glass plate is structured in the heated state by the desiccant itself, especially deepened locally. In this case, the cavities only arise as a result of the application of the drying agent and the encapsulation element to one another.

It is provided that the at least one cavity is formed under the effect of additional pressure, whereby the drying agent is pressed into the heated encapsulation element. For example, the flat encapsulation element and the desiccant can be applied to one another between two pressing tools and pressed together so that the desiccant displaces the material of the encapsulation element where it comes into contact. For this purpose, the desiccant consists of a material that has a higher melting point than the material of the flat encapsulation element.

It is preferably provided that the deformability of the encapsulation element is temporarily increased by the action of heat and that the encapsulation element is cooled again after the formation of the at least one cavity. In particular, it can be provided that the encapsulation element is temporarily put into a flowable state by the action of heat, in which it assumes the shape of a support surface of a base. As a result, the flat encapsulation element (for example a glass plate) can also be deformed without the action of external pressure. If the initially unstructured encapsulation element rests, for example in an oven, on a support surface that was previously covered in places with the desiccant, the material of the encapsulation element in the meltable state sinks due to its own weight into the gaps between adjacent areas that are covered with desiccant. As a result, spaces between the desiccant are filled so that the contours of the remaining desiccant also form the inner wall of the cavities.

It is preferably provided that a planar encapsulation element is used which has a predetermined, uniform layer thickness, and that the layer thickness of the encapsulation element is locally reduced by the shaping step in order to accommodate the desiccant. This can be done, for example, by displacing material by a drying agent which rests on a flat surface. However, an already structured support surface of a base, a pressing tool or a pressure ram can also be used in order not only to apply the desiccant to the initially flat surface of the encapsulation element, but also to press the desiccant into it and thus form the cavities. As a result, the planar encapsulation element is structured or at least restructured.

It is preferably provided that the drying agent is applied with a predetermined uniform layer thickness to the predetermined surface areas of the encapsulation element and that in the shaping step the at least one cavity is formed in the encapsulation element to a depth that is greater than the predetermined layer thickness of the drying agent. The surface of the encapsulation element should be shaped in such a way that the desiccant at least does not protrude from the remaining surface of the encapsulation element in the deformed state after the cavities have been formed.

In the heated state, the encapsulation element is preferably reshaped in such a way that the cavities are deeper than the height or the layer thickness of the desiccant, so that the desiccant does not reach as far as the opening or mouth of the respective cavity. This leaves a residual volume for later assembly in which penetrating moisture can spread over the entire desiccant. Accordingly, it is preferably provided that the drying agent is applied with a predetermined layer thickness to the predetermined surface areas of the encapsulation element and that in the shaping step the at least one cavity is formed in the encapsulation elements to a depth that is greater than the predetermined layer thickness of the drying agent. Alternatively, it can also be provided that, in the shaping step, the at least one cavity is formed in the encapsulation element to a depth which is exactly the same as the predetermined layer thickness of the drying agent. In the latter case, the desiccant extends to the outside of the encapsulation element in the deformed state.

With regard to the shaping step, it can be provided that when the at least one cavity is formed, a further surface of the encapsulation element opposite to the surface of the encapsulation element is locally arched. This local bulging of the rear encapsulation surface can occur in particular at those points where the desiccant is pressed on from the front.

The surface area covered with the drying agent can, for example, correspond to the cross-sectional area of an electronic, for example optoelectronic or electro-optical component, or encircle an outer circumference of one or more electronic components. In the latter case in particular - even with very large-area components - a complete protection against moisture-related premature aging is achieved, since moisture mostly diffuses along the adhesive surface between the finished encapsulation element and the carrier substrate of the electronic component.

It is preferably provided that the at least one cavity is formed by pressing at least one molded part made of desiccant into the material of the encapsulation element during or after the action of heat. The conventionally provided step of etching or sandblasting for forming the one or more cavities is thus omitted; instead, the cavities are formed at the same time as the desiccant and the encapsulation element are brought together. The shape obtained in this way is permanently retained after the deformed encapsulation element has cooled down and eliminates the need to send the desiccant and encapsulation element separately and to subsequently introduce the desiccant into the flat encapsulation element before it is mounted on the electronic component.

It is preferably provided that the drying agent is applied to an upwardly facing surface of the encapsulation element. In this case, the desiccant only needs to be placed on top and can then, after the encapsulation element has been heated, be pressed into its upper side. Likewise, the desiccant can be pressed onto an already heated encapsulation element, which is thus already deformable.

Alternatively, it is provided that the encapsulation element and the desiccant are applied to one another by applying the desiccant to predetermined surface areas of a base and applying the encapsulation element to the base covered with the desiccant. In this embodiment, the desiccant is arranged under the encapsulation element, so that the desiccant is first placed on the base and then the encapsulation element is placed on top. In this embodiment, the desiccant does not necessarily have to be pressed into the encapsulation element, but the free spaces between the areas of desiccant resting on the base can be filled by the material of the encapsulation element brought into a flowable state. For example, the encapsulation element is first placed and then made flowable by heating.

Accordingly, it is preferably provided that the encapsulation element is applied from above to the substrate covered with the desiccant and the material of the encapsulation element, in the heated state, is brought into contact with surface areas of the substrate that are not covered with the desiccant.

It is preferably provided that the substrate to be covered with the drying agent is a pressure stamp which prints the drying agent onto the encapsulation element. Thus, one and the same tool surface can be used to hold the desiccant in a predefined position (for example in the form of a matrix-like arrangement of a plurality of areas or molded parts made of desiccant) and to squeeze, print or at least apply the desiccant.

It can preferably also be provided that the base to be covered with the drying agent is a compression mold which presses the drying agent into the heated encapsulation element. The pressing process can take place during or after the heating. In particular, the drying agent can also be printed and pressed into the encapsulation element from below.

It should be provided that the base has a flat support surface onto which the desiccant is applied. This creates cavities that exactly match the shape and thickness of the desiccant.

Alternatively, it can be provided that the base has a support surface which has projections which are covered with the desiccant. In this embodiment, in particular cavities can be formed which are deeper than would be necessary in view of the layer thickness of the drying agent. Protective encapsulations can thus be formed in which there is a certain distance between the components to be encapsulated and areas of desiccant at the bottom of the cavities. In this way, penetrating moisture can initially be distributed within the volume of the respective cavity over the said cross-sectional area of the cavity and thus come into contact with the entire upper side of the desiccant. An even more effective protection against damage to the component is thereby achieved. For this purpose, the desiccant is not applied into the depressions, but rather onto the projections of the support surface of the base.

It is preferably provided that the encapsulation element consists of a glass, in particular a float glass. Likewise, however, the encapsulation element can also consist of another moisture-impermeable material, for example of a metal or of a Ceramics. Furthermore, the encapsulation element can also have a multilayer structure, for example from a plastic and an additional, moisture-impermeable layer.

It is preferably provided that the encapsulation element is heated by the action of heat to above a softening temperature or above a melting temperature. In particular, it can be provided that the encapsulation element consists of a glass (or also of a metal or a ceramic) and that the encapsulation element is heated to a temperature which is between 200.degree. C. and 2000.degree. As in the case of a glass, for example, it is not absolutely necessary that a melting temperature be reached and exceeded. It can also be sufficient to merely exceed a softening temperature at which the respective material (in particular glass) of the encapsulation element can be deformed at least with the aid of an additional pressure effect.

According to a preferred embodiment it is provided that the drying agent is activated at the same time by the action of heat. This particularly affects physisorbent desiccants, which are first heated up before use in order to remove already bound moisture, possibly still remaining due to the manufacturing process, and thus to make the desiccant usable. An additional heat treatment for activating the desiccant or for heating the material of the flat encapsulation element is therefore not required. The method steps of heating the encapsulation element, introducing the drying agent into the cavities (which are conventionally carried out separately) and activating the drying agent can thus be combined into a single method step.

The drying agent is sintered at the same time by the action of heat. The desiccant does not need to be in its final state when it is applied to the surface of the encapsulation element, but can be converted into the final state during the action of heat. In addition, the action of heat can be used in particular to bring the desiccant into close contact with the respective contact surfaces of the material of the encapsulation element right from the start. This also achieves better adhesion between the desiccant and the material of the encapsulation element in the region of the cavity than if the desiccant is only introduced into the cavity later, as is conventional, and there, for example, only the bottom of the cavity is brought into firm contact. In particular, during the simultaneous heating of the desiccant and the encapsulation material, the desiccant can also bake on the side surfaces or on the side areas of the wall of the cavity.

It is preferably provided that the drying agent is applied to an unstructured surface of the encapsulation element. This embodiment is associated with considerable savings in labor, time and costs, since the structuring of the encapsulation element, which is conventionally always necessary, for example chemically or mechanically, is completely eliminated. There are also no masking steps to protect the surface areas to be protected from the effects arising during structuring.

It is preferably provided that a chemisorbing or physisorbing material is used as the drying agent. For example, a metal oxide, for example barium oxide, can be used as the chemisorbing material. Zeolite or silica gel, for example, are suitable as the physisorbing material. In particular, those drying agents can be used that do not require shielding from the normal outside air by a protective gas until they are finally enclosed by the encapsulation of the component.

In principle, the desiccant material used to form the cavities does not have to consist entirely of desiccant, but this material can also contain other components that serve, for example, for solidification, hardening or better bonding to the material of the encapsulation element. Furthermore, any other desired additive can be contained in the drying agent. However, the drying agent must contain at least some (preferably more than 50 percent, in particular more than 75 percent) of a material that binds moisture.

It can be provided that the drying agent is applied to a plurality of surface areas of the surface of the encapsulation element which form a matrix-like arrangement on the surface of the encapsulation element. In this embodiment, in particular, several areas of the surface of the encapsulation element can be reshaped to form cavities in order to encapsulate a large number of electronic components when the reshaped encapsulation element is connected to the carrier substrate with the components. Alternatively, however, an area in the vicinity of one or more (or also all) components can be reshaped into a single cavity. Such a cavity can For example, surround a single, several or all components in a ring or in some other way. The area covered with the desiccant and recessed to form a cavity (for example an edge area of the encapsulation element) runs around that base area on the surface of the encapsulation element which corresponds to the base area of the protective components.

It is preferably provided that a protective encapsulation is produced for an electro-optical or optoelectronic component, in particular for a light-emitting diode, an organic light-emitting diode, a display or a surface light source. However, any other components, in particular those that are to be formed on a substrate, for example a semiconductor substrate, can be encapsulated with the aid of the protective encapsulation according to the invention.

The manufacturing process described allows for the first time the use of even thinner protective encapsulations with a maximum layer thickness of less than 0.5 mm, since the areas of the encapsulation element that have a reduced layer thickness below the cavities are reinforced by the desiccant from the start, which contributes to mechanical stability and better protects against mechanical damage, for example against breakage damage during transport.

It is preferably provided in particular that the encapsulation element of the protective encapsulation has a maximum layer thickness of less than 0.5 mm, preferably between 0.5 and 0.2 mm. The method according to the invention thus enables the use of thinner encapsulation plates, for example glass plates or ceramic plates, for the production of encapsulations for electronic components. This reduction in the required minimum layer thickness results in a material saving and thus a cost saving.

It is preferably provided that the desiccant is thermally baked onto the base and the side wall of the at least one cavity. Since the desiccant does not come into contact with the material of the encapsulation element afterwards, but rather during the formation and formation of the cavities (and indeed when it is heated), there is greater adhesion to the side walls or the lateral areas of the respective cavity, as if, as is customary, the desiccant is only subsequently pressed onto the bottom of the cavity at room temperature.

It is preferably provided that the side of the flat encapsulation element on which the at least one cavity and the desiccant are arranged form an exposed surface of the protective encapsulation. Thus, with the method according to the invention, a protective encapsulation can be produced, in the cavities of which the desiccant is more firmly bound than in the case of a subsequent application of the desiccant. With this protective encapsulation, in particular optoelectronic and electro-optical components, for example light-emitting diodes (in particular organic light-emitting diodes) surface light sources, displays or any other electronic components can be encapsulated.

• 1 eine schematische Darstellung eines nicht erfindungsgemäßen, die Erfindung illustrierenden verkapselten elektronischen Bauteils mit einer Mehrzahl von elektronischen Bauelementen 3,
• 2 eine schematische Darstellung eines nicht erfindungsgemäßen, die Erfindung illustrierenden, noch nicht verkapselten elektronischen Bauteils sowie eines flächigen Verkapselungselements mit zunächst noch unstrukturierten Oberflächen,
• die 3 bis 7 Verfahrensschritte einer ersten , die Erfindung illustrierenden Herstellungsverfahrens,
• die 8 bis 10 Verfahrensschritte einer zweiten , die Erfindung illustrierenden Herstellungsverfahrens,
• die 11 bis 14 Verfahrensschritte einer dritten , die Erfindung illustrierenden Herstellungsverfahrens,
• die 15 bis 18 Verfahrensschritte einer vierten , die Erfindung illustrierenden Herstellungsverfahrens,
• die 19 eine erfindungsgemäße Ausführungsform eines elektronischen Bauteils mit genau einem elektronischen Bauelement,
• 20 eine andere erfindungsgemäße Ausführungsform eines elektronischen Bauteils mit einer Vielzahl von elektronischen Bauelementen,
• 21 einen herkömmlichen Verfahrensablauf zur Herstellung und Montage einer Schutzverkapselung, und
• 22 einen die Erfindung illustrierenden Verfahrensablauf zur Herstellung und Montage einer Schutzverkapselung.

The invention is explained below with reference to the figures. Show it:

• 1 a schematic representation of an encapsulated electronic component not according to the invention, illustrating the invention, with a plurality of electronic components 3 ,
• 2 a schematic representation of an electronic component not yet according to the invention, illustrating the invention, not yet encapsulated, as well as a flat encapsulation element with initially unstructured surfaces,
• the 3 until 7th Method steps of a first manufacturing method illustrating the invention,
• the 8th until 10 Method steps of a second manufacturing method illustrating the invention,
• the 11 until 14th Method steps of a third manufacturing method illustrating the invention,
• the 15th until 18th Method steps of a fourth manufacturing method illustrating the invention,
• the 19th an embodiment according to the invention of an electronic component with exactly one electronic component,
• 20th another embodiment according to the invention of an electronic component with a plurality of electronic components,
• 21 a conventional process sequence for the production and assembly of a protective encapsulation, and
• 22nd a process sequence illustrating the invention for the production and assembly of a protective encapsulation.

1 shows a schematic cross-sectional view of an electronic component 20th , which has a plurality of electronic, in particular optoelectronic or electro-optical Components 3 having on a carrier substrate 4th are arranged. The electronic component 20th has an encapsulation 10 consisting of a substantially flat encapsulation element 1 with two main surfaces parallel to each other and a desiccant 5 is formed. The carrier substrate 3 facing surface of the encapsulation element 1 is a textured surface; in particular, it has a large number of cavities 8th (or at least a cavity 8th ). In all or at least some of the cavities 8th is a desiccant 5 arranged, preferably at the bottom of the respective cavity. The drying agent prevents damage to the electronic components 3 due to moisture moving along the interface between the carrier substrate 3 and the encapsulation element 1 can penetrate. Moisture can also diffuse out of the adhesive used, for example, as long as the adhesive is not yet completely cured and dry. Likewise, even during the usually several years of operation, small amounts of moisture can pass through the adhesive layer or along the interface between the carrier substrate and the encapsulation element with the components 3 advance. That in the cavities 8th intended desiccant 5 absorbs this moisture, in particular through chemisorption or physisorption, and thereby prevents damage to the components 3 .

2 shows schematically the still unencapsulated electronic component with the on one side of the carrier substrate 3 arranged electronic components 4th . Furthermore, there is a flat encapsulation element 1 shown, the lateral dimensions of which, for example, essentially those of the carrier substrate 3 can match; At least the encapsulation element should cover the base areas of all electronic components to be encapsulated 4th cover. The surface later facing the carrier substrate in the finished component 1a is initially still unstructured, but should have (for example several) cavities 8th be provided (of which in 2 one is indicated by dashed lines), which accommodate the desiccant and the electronic components 4th enclose. Conventionally, the cavities are produced either by a sandblasting process or by chemical etching, each of which requires masking steps. The present illustrative examples of the method considerably simplify the production of an encapsulation element with a structured surface that has one or more cavities.

the 3 until 7th show process steps of a first process. According to 3 become a flat encapsulation element 1 and a desiccant 5 arranged on top of one another. The desiccant 5 is on given areas 11 a (preferably initially flat) surface 1a of the encapsulation element 1 arranged. For example, the desiccant can be on an upward-facing surface 1a placed, printed or otherwise applied. The initially planar encapsulation element 1 has a specified layer thickness D. . The drying agent can also be used 5 with a uniform, specified layer thickness d1 be applied. For example, the desiccant 5 in the form of one or more molded parts 6th , each with a preferably identical layer thickness d1 own on the encapsulation element 1 be put on. Alternatively, the drying agent can also have a predetermined layer thickness d1 be printed, for example if it is present as a printing mass.

4th shows the arrangement of the encapsulation element 1 and desiccants 5 after they were applied to each other. The desiccant 5 protrudes completely from the surface 1a of the encapsulation element 1 emerged. According to the invention, therefore, a shaping step is used in which the surface 1a is reshaped to form one or more cavities.

For this purpose, the material of the encapsulation element is exposed to heat 1 deformed as shown in the following figures. It should be noted, however, that the encapsulation element can also be used as an alternative 1 also warmed up first and only afterwards (when coming into contact with the desiccant 5 ) can be deformed.

According to 5 will the in 4th Arrangement shown from encapsulation element 1 and desiccants 5 between two molds 7th compressed. A first compression mold can, for example, be a base 12th being. The pressing process of this shaping step 15th ( 6th ) takes place under the influence of heat W. instead of. For example, the molds 17th be heated, or the action of heat can take place in some other way, for example through the surrounding atmosphere, for example in a furnace. The temperature is increased, for example, to a temperature which is between 200 ° C and 2000 ° C and which corresponds, for example, to a melting temperature or a softening temperature of the material of the encapsulation element (these temperature-related features can also be combined with the examples of the method mentioned below) . According to 5 become the molds 17th compressed under the action of pressure p, whereby the in 6th shown arrangement results.

According to 6th became the desiccant in the material of the encapsulation element 1 pressed in, creating the previously unstructured (for example overhead) surface 1a to a structured surface 2 was reshaped, which now has one or more cavities 8th having. The cavities 8th are therefore not pre-structured by additional processing steps before the drying agent is introduced. Instead, the cavities are opened by pressing in the desiccant 5 educated. The initial layer thickness D. of the encapsulation element ( 5 ) is thus locally reduced, at least by the layer thickness d1 of the desiccant. The exposure to heat W. (and optionally also the application of pressure) only needs to be applied temporarily.

7th shows the protective encapsulation obtained in this way 10 , their encapsulation element 1 a structured surface on at least one side 2 with at least one cavity 8th having. The desiccant is in the cavities 5 Arranged so that it doesn't cover the outermost areas of the textured surface 2 protrudes and is thus arranged completely within the cavities.

the 8th until 10 show another procedure.

According to 8th becomes the desiccant 5 as a printing mass 19th (i.e. in a manner similar to a printing ink) onto the encapsulation element 1 upset. For example, one of the two compression molds is used for this purpose 17th as a pressure stamp 16 formed, for example, projections 18th may have that with a film of the desiccant 5 are covered. Of course, alternative printing processes can also be used, for example screen printing processes. In this process, a printing mask is used, with the desiccant 5 or the mass to be printed in the openings of the printing mask on the element to be printed, here on the encapsulation element 1 , is applied. 8th shows that the encapsulation element 1 is already warmed up (exposure to heat W. ) when it comes to the desiccant 5 is brought into contact. Thus, the sequence of applying the encapsulation element and desiccant to one another and performing the shaping step 15th variable; in particular, both steps can be carried out simultaneously. Furthermore, the heating of the encapsulation element, which enables the shaping step, can also be carried out before the encapsulation element and the drying agent are brought into contact with one another.

According to 8th becomes the printing mass 19th not merely imprinted to be on the encapsulation element 1 stick to it, but the printing mass 19th is additionally under the action of pressure p (with simultaneous action of heat W. or at least when the encapsulation element has already been preheated 1 ) into the encapsulation element 1 pressed in. The encapsulation element is therefore not only printed from the outside, but also deformed.

This creates the arrangement according to 9 where the previously flat surface 1a is now structured and cavities 8th has, by the desiccant pressed in 5 , if necessary (as in 9 shown) additionally by protrusions 18th in the contact surface of the plunger 16 originate.

10 finally shows the completed protective encapsulation 10 with the encapsulation element 1 and the desiccant 5 that is in cavities 8th a surface structured under the action of heat (and preferably additional pressure) 2 are arranged. As in 10 recognizable, have the cavities 8th a depth that is greater than the layer thickness of the drying agent introduced 5 . The side wall thus protrudes 9 of the respective cavities via the desiccant 5 addition and offers space for protruding areas of the electronic components to be encapsulated of the electronic component. The one for the structured surface 2 opposite surface 1b of the encapsulation element 1 can remain unstructured, but it can also be deformed, for example locally arched - depending on the shape of the support surface of the respective mold 17th (e.g. below in 9 ).

the 11 until 14th show further procedures. According to 11 first becomes the desiccant 5 on a pad 12th arranged. The underlay 12th can be, for example, a compression mold, but it does not have to be used for pressing, but can also be a base for a melting or flow process that takes place exclusively under the action of heat, in which the encapsulation element 1 when heated, it begins to reshape itself solely due to its own weight. According to 11 the desiccant is applied to specified areas 14th the support surface 13th the document 12th upset. These areas 14th can for example correspond to those surface areas in which cavities in the encapsulation element 1 are to be trained.

The desiccant 5 can, for example, in the form of one or more molded parts 6th be arranged on the base, for example in the form of a matrix-like arrangement of several molded parts. The molded parts can, for example, have a uniform layer thickness d1 own. They can, for example, have been punched out of a flat raw material or otherwise separated and then in intended relative positions to one another on the base 12th to be ordered. Alternatively, the desiccant 5 also in the form of a printing compound 19th (in the 11 until 14th not explicitly shown) on the base 12th be applied.

According to 11 is based on the arrangement from the document 12th and desiccants 5 an as yet unstructured encapsulation element 1 applied, for example placed from above. This results in the arrangement according to 12th , in which the initially undeformed encapsulation element 1 on one or more areas of desiccant 5 consists, in turn, through the document 12th being held. After that, at the latest, you begin to apply the heat W. , whereby the temperature T is increased to the material of the encapsulation element 1 to bring into a flowable, deformable state in which it changes its shape due to its own weight (or optionally under additional pressure) and in particular the spaces between adjacent areas of desiccant 5 replenishes.

13th shows the result of the shaping step, which causes the material of the encapsulation element that has been brought into the flowable state to dissolve 1 evenly over the entire contact surface of the pad 12th distributed and thus the support surface 12th between those with desiccant 5 covered areas (ie the surface of the pad) contacted. Thus became the lower surface 1a ( 12th ) of the encapsulation element 1 reshaped and now has cavities, each of which is on the contact surface 13th desiccant lying on the surface 5 surround and enclose laterally.

14th shows the encapsulation element produced in this way 10 with the structured surface (still pointing downwards as shown) 2 in which the desiccant 5 in cavities 8th is included. The opposite surface 1b can either be flat or locally curved, wavy or otherwise deformed, as in 14th indicated by dashed lines. For this purpose, undulating or otherwise uneven contact surfaces can be used, for example in order to increase the breaking strength of the encapsulation element to be produced 10 while saving material at the same time.

the 15th until 18th show further procedures. According to 15th will (as in 11 ) first the desiccant 5 on a pad 12th applied and then the flat encapsulation element 1 placed on this arrangement of pad and desiccant. The underlay 12th can also be a press mold 17th be the (see 16 and 17th ) under additional pressure with another mold 17th is pressed together. In addition, the base or the press mold can also be a pressure stamp 16 be, which is used to selectively on predetermined areas of the one surface 1a of the encapsulation element 1 the desiccant 5 to print. So shows 15th that the desiccant 5 for example on projections 18th the support surface 13th is applied; either in the form of a printing mass 19th or in the form of one or more molded parts 6th . The planar encapsulation element is finally based on this arrangement 1 hung up.

According to 16 is then the effect of heat W. or a heat treatment carried out at which the temperature of the encapsulation element 1 is increased.

Can be used as the material of the encapsulation element 1 can, as in all other examples, be a glass, for example a float glass, but also a ceramic or a metal or a multilayer material with at least one water-impermeable layer. In the case of a glass, the temperature T can be increased to above a softening temperature or a melting temperature of the glass in order to protect the material of the encapsulation element 1 to bring into the flowable state. According to 16 become the desiccant and the encapsulation element 1 using two or more dies 17th compressed, whereby the encapsulation element 1 is deformed and as a result of the increase in temperature (and preferably also the action of pressure) assumes a shape that is created by the contact surfaces of both compression molds 17th is given.

17th shows as a result of this shaping step that the material of the encapsulation element 1 the entire support surface 13th (or outer surface) of the lower mold 17th covered and thus the spaces between adjacent projections 18th ( 15th ) completely filled out. This creates cavities 8th which each include the desiccant and which are deeper than the layer thickness of the desiccant 5 is equivalent to.

18th shows the finished protective encapsulation 10 after the material of the encapsulation element has cooled down 1 . In the lower, structured surface 2 are the cavities 8th arranged, preferably a floor 17th and a side wall 9 own. The desiccant 5 has a layer thickness d1 that is smaller than the depth of the cavities 8th . At the bottom of the cavities 8th Thus, the original layer thickness of the encapsulation element locally except for a reduced layer thickness d2 of the encapsulation element 1 reduced. The original layer thickness D. of the encapsulation element 1 is preferably increased by more than the layer thickness during reshaping d1 of the desiccant 5 decreased. So stays enough space to accommodate the respective electronic component.

19th shows an embodiment of an electronic component 20th , for example, exactly one electronic component 4th having. The electronic component can, for example, be a light-emitting diode, in particular an organic light-emitting diode, but alternatively any desired electro-optical or optoelectronic component. In particular, light-emitting diodes, screens, displays, surface lights or photovoltaic elements come into consideration as electronic components. According to 19th owns the electronic component 20th a carrier substrate for the electronic component 4th . The latter includes, in particular, a first electrode 4a , a second electrode 4b and a stack of layers arranged therebetween 4c , which is in particular an active layer stack. The stack of layers is used, for example, to convert electrical energy into electromagnetic radiation or vice versa.

The electronic component 20th also has a protective encapsulation 10 coming from the encapsulation element 1 and the desiccant 5 is formed. The encapsulation element 1 has at least one cavity 8th , that is, a recess in the carrier substrate 3 facing surface. In the cavity 8th are the desiccant and an area of the electronic component 4th arranged. Basically it is under the cavity 8th understood any indentation in the surface, in particular the main area of a planar encapsulation element. The encapsulation element can in particular be a glass plate, metal plate, ceramic plate or a multilayer arrangement with at least one water-impermeable layer. The structured surface of the encapsulation element 1 (in 19th the lower surface) is outside the cavities 8th on the carrier substrate 3 attached, for example using an adhesive 21 . This forms a thin adhesive layer which, due to the manufacturing process, may still contain a certain amount of residual moisture. This is due to the desiccant 5 bound and therefore does not get into the electronic component 4th . Likewise, during the service life of the component 20th (or during the intended service life of typically many years) moisture between the carrier substrate 3 and the encapsulation 10 into the cavity 8th penetrates through the desiccant 5 bound. This prevents premature aging and deterioration of the electronic component 20th due to the component 4th even penetrated moisture. For example, insulating transparent oxides (ITO) can be used as the carrier substrate, in particular in the case of optoelectronic components in which the carrier substrate is intended to be permeable to the emitted radiation wavelength.

As a drying agent 5 In principle, all chemisorbent or physisorbent materials come into consideration, for example zeolite or barium oxide, to name just a few examples. In contrast to a conventional electronic component, as in 19th recognizable, the desiccant 5 not just with the floor area 7th the at least one cavity 8th firmly connected, but is also in firm contact with the side wall 9 of the cavities 8th . Furthermore, due to the shaping or reshaping of the encapsulation element that has taken place under the action of heat 1 the desiccant 5 firmly to the inner wall, ie both to the floor 7th as well as on the side wall 9 of the respective cavity 8th baked on and therefore adheres better to the material of the encapsulation element than with the conventional subsequent introduction of the desiccant 5 in previously formed cavities.

In addition, since the cavities only occur when the encapsulation element is brought into contact 1 with the desiccant 5 are formed, manufacturing steps for the separate transport and packaging of the desiccant and encapsulation element and manufacturing steps for the previous structuring of the encapsulation element to form the cavities are dispensed with.

20th shows a further embodiment of an electronic component 20th . According to 20th indicates the electronic component 20th a plurality of electronic components 4th on, for example, a matrix-like arrangement M. on the base of the carrier substrate 3 can form. The electronic component 20th has a protective encapsulation 10 , its encapsulation element 1 laterally in a lateral direction over the electronic components 4th in the field of electronic components 4th a cavity 8th' (with or without desiccant) and also an additional one, the at least one component 4th surrounding, but not covering, outer cavity 8th has, at least partially with desiccant 5 is filled. On the base of the carrier substrate 3 or the encapsulation element 1 runs around this additional cavity 8th one or preferably all of the electronic components 4th and thereby prevents moisture-related damage that could arise from penetrating moisture from the edge of the interface between the carrier substrate and the encapsulation element. Thus, according to needs 20th not every cavity (especially not the cavity 8th' to accommodate the electronic components 4th ) with a desiccant 5 to be provided, but it is sufficient if an outside circumferential cavity 8th with a desiccant 5 is provided. This outer, around the perimeter of less or all of the electronic components 4th extending cavity 8th with the desiccant 5 can for example be ring-shaped. It can also run around the components in a rectangular manner or in some other way.

In the in 20th The cross-sectional view shown, which shows a cut surface perpendicularly through the carrier substrate and the encapsulation element, is respectively left and right of the matrix-shaped arrangement M. a cross section of the circumferential cavity 8th recognizable. This cavity is at least partially with the desiccant 5 filled out.

Moreover, instead of the matrix-like arrangement M. several components 4th any other arrangement of components or only a single component can be provided. Furthermore, instead of the cavity 8th' , which covers and encloses all components, including a plurality of cavities 8th' be provided which each cover and enclose one or some of the components.

Since in the method according to one of the illustrative examples disclosed here, the drying agent does not have to be separately shaped, transported, packaged and handled before it is introduced into the cavities, structures made of drying agents can be ring-shaped or in some other way around the outer circumference of the electronic components easier to manufacture; right from the start after the drying agent has been printed or otherwise applied to the flat encapsulation element 1 the encapsulation element forms a stable base to protect the desiccant 5 .

21 shows a conventional process sequence for producing and assembling a protective encapsulation. First, an unstructured encapsulation element, for example a glass plate (for example made of float glass), a metal plate or a ceramic plate is provided. Then the still unstructured plate (or the still unstructured, flat encapsulation element) is structured. For this purpose, a mask layer is usually applied to the encapsulation element and then the mask layer itself is first structured. The encapsulation element is then processed through the structured mask layer, for example by sandblasting or by chemical etching. In this way, cavities are formed on predefined surface areas of the encapsulation element. The mask layer is then removed and the structured encapsulation element cleaned and packaged ready for transport for shipping.

The desiccant is provided separately from this and then packaged in a manner suitable for shipping. The provision of the drying agent can for example comprise the extrusion of a mass of drying agent in order to obtain a flat strip of drying agent mass. However, the mass of drying agent is not yet suitable in this form to be applied to the structured encapsulation element later - by the user when encapsulating an electronic component - because the mass of drying agent itself is not yet structured.

Therefore, the desiccant itself is first structured (as part of the packaging). For example, a strip of desiccant compound can be applied to a carrier film and then subjected to a punching process that punches out certain surface areas of the desiccant (possibly with the carrier film) and thus leaves a defined, for example matrix-shaped arrangement of molded parts made of drying compound, which later with the aid of the carrier film can be applied to a structured encapsulation element.

The arrangement of carrier film and desiccant is then packaged and sent to the user.

There, the encapsulation element and the desiccant are each unpacked, cleaned if necessary and placed in a moisture-free atmosphere (for example in a glove box). There the desiccant (or the film with the desiccant arranged thereon) is then applied to the structured encapsulation element with the cavities. The desiccant ideally reaches the cavities with a precise fit and can in particular be pressed onto the bottom of the cavities. The lateral dimensions of the molded parts made of desiccant correspond approximately to the lateral dimensions of the cavities. Due to certain tolerances, however, the lateral dimensions of the molded parts made of desiccant will be slightly smaller than the lateral dimensions of the cavities. Thus, the desiccant will have a slight distance from the side wall of the cavity and will only be pressed onto the bottom of the cavity. Due to the action of pressure, the desiccant then has to adhere to the encapsulation element.

The protective encapsulation completed in this way by the user is then applied to the carrier substrate with the at least one electronic component, which results in an encapsulated component.

The separate shipping of the encapsulation element and desiccant in this procedure is due, among other things, to the fact that the desiccant is only introduced into the cavities of the encapsulation element shortly before the encapsulation of the electronic component and is handled and shipped separately from the structured encapsulation element until then. A further disadvantage is that complex processing steps are initially required to structure the initially unstructured encapsulation element. Another disadvantage is that the already activated and at the same time packaged desiccant may have to be protected from moisture penetration during the entire transport route.

22nd shows an illustrative example of a process flow. First, the encapsulation element and the desiccant are provided, the encapsulation element still being unstructured. The drying agent is applied to the (unstructured) encapsulation element. For this purpose, the drying agent is provided in a structured form, for example in the form of several molded parts made of drying agent, which are arranged in a predetermined matrix-like arrangement relative to one another, or in the form of a mass of drying agent that is produced by a printing process, for example by a screen printing process or by another printing process, is printed directly onto the unstructured encapsulation element. The encapsulation element provided with the desiccant is then or at the same time subjected to a shaping step in which the encapsulation element is deformed under the action of heat (and optionally under the action of additional pressure) in such a way that cavities around the desiccant in those surface areas in which the desiccant rests or is in contact develop. A separate mask layer is therefore not required for structuring the encapsulation element. The action of heat can take place, for example, in an oven, in which the encapsulation element is heated, for example on a base, between two compression molds or on some other support surface. In particular, when the encapsulation element is heated, the desiccant can be pressed into the mass of the encapsulation element. Any other desired method of the examples mentioned in this application can also be used.

Finally, the structured encapsulation element is removed from the furnace and, after cooling, forms the finished protective encapsulation 10 which is then sent to the user. There it is applied to the carrier substrate with the at least one electronic component, if necessary after optionally repeated brief heating to activate the drying agent. This creates the encapsulated electronic component.

The finished protective encapsulation can, in turn, be applied to the carrier substrate with the aid of an adhesive.

In comparison with the conventional process sequence, a significantly lower number of work steps is required. This reduces the time and costs involved in producing one of the protective encapsulation produced according to the invention and the electronic component encapsulated therewith.

Claims (11)

Protective encapsulation (10) for at least one electronic component (20), with a flat encapsulation element (1) which has a structured surface (2) with at least one cavity (8) on at least one side, wherein a drying agent (5) is pressed into the encapsulation element (1), whereby the at least one cavity (8) is formed, and wherein the material of the drying agent (5) has a higher melting point than the material of the encapsulation element (1), and wherein the drying agent (5) is sintered in the at least one cavity (8) by the action of heat. Protective encapsulation (10) after Claim 1 , the protective encapsulation being provided for exactly one electronic component. Protective encapsulation (10) according to at least one of the preceding claims, the depth of the cavity (8) being greater than the layer thickness of the drying agent (5). Protective encapsulation (10) according to at least one of the Claims 1 or 2 , the depth of the cavity (8) being the same as the layer thickness of the drying agent (5). Protective encapsulation (10) according to at least one of the preceding claims, wherein the encapsulation element (1) has a further surface of the encapsulation element opposite the cavity (8), which is locally curved. Protective encapsulation (10) according to at least one of the preceding claims, wherein the encapsulation element (1) consists of float glass. Protective encapsulation (10) according to at least one of the preceding claims, wherein the encapsulation element (1) has a multilayer structure made of a plastic and an additional, moisture-impermeable layer. Protective encapsulation (10) according to at least one of the preceding claims, wherein the drying agent (5) is formed from zeolite or silica gel. Protective encapsulation (10) according to at least one of the preceding claims, wherein the drying agent (5) contains more than 75 percent a material that binds moisture. An electronic component (20) comprising: - a carrier substrate (3), - At least one electronic component (4) which is arranged on the carrier substrate (3), and - A protective encapsulation (10) with a flat encapsulation element (1) and a drying agent (5), wherein the encapsulation element (1) has at least one cavity (8) facing the at least one electronic component (4), and wherein the drying agent (5) is pressed into the encapsulation element (1), whereby the at least one cavity (8) is formed, and wherein the material of the drying agent (5) has a higher melting point than the material of the encapsulation element (1), and wherein the drying agent (5) is sintered in the at least one cavity (8) by the action of heat. Electronic component (20) according to the preceding claim, wherein the optoelectronic component is a light-emitting diode, an organic light-emitting diode, a display or a surface light source.

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