Patent Application
20190214536
This disclosure relates to a method of producing an optoelectronic component, and an optoelectronic component.
Optoelectronic components, for example, light-emitting diode components are known in which an optoelectronic semiconductor chip is embedded into an embedding material that forms a housing comprising extremely compact dimensions. It is known to use optically reflective embedding material so that light emitted by the optoelectronic semiconductor chips in lateral directions is deflected in a forward direction.
We provide a method of producing an optoelectronic component including providing a carrier; arranging a structured reflector above a top side of the carrier; arranging an optoelectronic semiconductor chip including a top side and an underside opposite the top side in an opening of the reflector, wherein the underside of the optoelectronic semiconductor chip faces the top side of the carrier; arranging an embedding material above the top side of the carrier, wherein the optoelectronic semiconductor chip is at least partly embedded into the embedding material, as a result of which a composite body including the optoelectronic semiconductor chip, the reflector and the embedding material is formed; and detaching the composite body from the carrier.
We also provide an optoelectronic component including a composite body including an embedding material, a reflector, and an optoelectronic semiconductor chip, wherein the optoelectronic semiconductor chip is at least partly embedded into the embedding material, the optoelectronic semiconductor chip is arranged in an opening of the reflector, and an underside of the optoelectronic semiconductor chip and an underside of the reflector terminate flush and are at least partly exposed at an underside of the composite body.
Our method of producing an optoelectronic component comprises steps of providing a carrier; arranging a structured reflector above a top side of the carrier, arranging an optoelectronic semiconductor chip comprising a top side and an underside opposite the top side in an opening of the reflector, wherein the underside of the optoelectronic semiconductor chip faces the top side of the carrier, arranging an embedding material above the top side of the carrier, wherein the optoelectronic semiconductor chip is at least partly embedded into the embedding material, as a result of which a composite body comprising the optoelectronic semiconductor chip, the reflector and the embedding material is formed, and detaching the composite body from the carrier.
In the optoelectronic component obtained by this method, the reflector may reflect light emitted by the optoelectronic semiconductor chip and thereby bring about a deflection of the light in a preferred emission direction. As a result, light emitted by the optoelectronic component obtained by the method is at least partly directed. Since light emitted by the optoelectronic semiconductor chip in other spatial directions is at least partly deflected in the preferred emission direction at the reflector and is thus utilized, the light is not lost. As a result, the optoelectronic component obtained by the method may comprise a high brightness and a high efficiency.
The optoelectronic component obtained by the method may advantageously comprise very compact external dimensions. This is achieved in particular by virtue of the fact that the optoelectronic component need not comprise any further major component parts apart from the optoelectronic semiconductor chip, the reflector, and the embedding material.
The reflector may be formed as a flat sheet or as a flat film, in particular as a metallic leadframe or as a metal film. Advantageously, the reflector comprises a high optical reflectivity as a result. Moreover, the reflector is obtainable simply and cost-effectively. Structuring the reflector may be carried out by laser cutting, for example.
The carrier may be provided with an adhesive film arranged at its top side, in particular with an adhesive film releasable by thermal treatment or by electromagnetic irradiation. In this example, the reflector is arranged on the adhesive film. Advantageously, providing the adhesive film enables a simple and reliable later detachment of the composite body from the carrier. This reduces the risk of damage to the composite body and the risk of damage to the optoelectronic component produced. For the purpose of detaching the composite body, the adhesiveness of the adhesive film may be reduced, for example, by a thermal treatment or electromagnetic irradiation, for example, irradiation with UV light.
One or more electrical contact pads of the optoelectronic semiconductor chip may be arranged at the underside of the optoelectronic semiconductor chip. The electrical contact pads may electrically contact the optoelectronic semiconductor chip and may form electrical connection pads in the optoelectronic component obtained by the method.
The optoelectronic semiconductor chip may be formed as a flip-chip. By way of example, the optoelectronic semiconductor chip may be formed as a sapphire flip-chip.
The optoelectronic semiconductor chip may be formed as a volume emitting light-emitting diode chip. Advantageously, in the optoelectronic component obtained by the method, light emitted by the volume emitting light-emitting diode chip in spatial directions that do not correspond to the preferred emission direction of the optoelectronic component is at least partly reflected at the reflector of the optoelectronic component and deflected in the preferred emission direction. As a result, these portions of the light emitted by the optoelectronic semiconductor chip are also at least partly utilized.
The top side of the optoelectronic semiconductor chip may be covered by the embedding material. This advantageously makes it possible to carry out the process of arranging the embedding material by a particularly simple process step that may be carried out cost-effectively. Covering the top side of the optoelectronic semiconductor chip by the embedding material is made possible by the fact that the embedding material may be formed as optically transparent. This in turn is made possible by the fact that the embedding material need not reflect light emitted in undesired spatial directions. Rather, the reflector reflects such light in the optoelectronic component obtained by the method.
The embedding material may comprise a silicone. Advantageously, the embedding material may thereby be cost-effectively obtainable and easy to process. Moreover, the embedding material may comprise a high durability. In particular, an embedding material comprising a silicone may comprise a reduced susceptibility to cracking compared to other embedding materials. The use of an embedding material comprising a silicone may also support detaching the composite body from the carrier without any problems.
The embedding material may comprise embedded wavelength-converting particles. The wavelength-converting particles embedded into the embedding material may be provided to at least partly convert light emitted by the optoelectronic semiconductor chip into light comprising a different wavelength. As a result, in the optoelectronic component obtained by the method, by way of example, white light may be generated from light emitted by the optoelectronic semiconductor chip and comprising a wavelength from the blue or ultraviolet spectral range, the white light being emitted by the optoelectronic component.
Arranging the embedding material may be carried out by a molding process or a casting process. Advantageously, arranging the embedding material may be carried out simply and cost-effectively as a result.
Before arranging the embedding material, a further step may be carried out by arranging a film comprising a wavelength-converting material above the top side of the optoelectronic semiconductor chip. Afterward, the film is embedded into the embedding material such that the composite body also comprises the film. In the optoelectronic component obtained by this method, the wavelength-converting material of the film may at least partly convert light emitted by the optoelectronic semiconductor chip into light comprising a different wavelength. As a result, the embedding material need not comprise embedded wavelength-converting particles.
The optoelectronic semiconductor chip may be arranged in the opening of the reflector such that a distance between the optoelectronic semiconductor chip and the reflector is of identical magnitude on all sides of the optoelectronic semiconductor chip. In this example, the distance between the optoelectronic semiconductor chip and the reflector that is identical on all sides of the optoelectronic semiconductor chip is maintained within the scope of the positioning accuracy of the optoelectronic semiconductor chip. A distance between the optoelectronic semiconductor chip and the reflector that is as far as possible identical on all sides of the optoelectronic semiconductor chip may advantageously support a particularly homogeneous light emission of the optoelectronic component obtained by the method.
The reflector may be formed as a grid comprising a plurality of openings. The openings may be created by laser cutting, for example.
A plurality of optoelectronic semiconductor chips may be arranged respectively in openings of the reflector. In this example, the composite body formed comprises all the optoelectronic semiconductor chips. After detaching the composite body, a further step of dividing the composite body is carried out. As a result, the method advantageously makes it possible to simultaneously produce a plurality of optoelectronic components in common processing steps. The production costs per optoelectronic component and the work time required to produce an optoelectronic component are reduced as a result.
An optoelectronic component comprises a composite body comprising an embedding material, a reflector and an optoelectronic semiconductor chip. In this example, the optoelectronic semiconductor chip is at least partly embedded into the embedding material. The optoelectronic semiconductor chip is arranged in an opening of the reflector. In this example, an underside of the optoelectronic semiconductor chip and an underside of the reflector terminate flush and are at least partly exposed at an underside of the composite body.
In the optoelectronic component, the reflector at least partly reflects light emitted by the optoelectronic semiconductor chip in spatial directions that do not correspond to a desired emission direction of the optoelectronic component, and thereby deflects the light in the desired emission direction of the optoelectronic component. As a result, the deflected light is made usable and not lost. As a result, the optoelectronic component may advantageously comprise a high brightness and a high efficiency.
One or more electrical contact pads of the optoelectronic semiconductor chip may be arranged at the underside of the optoelectronic semiconductor chip and are exposed at the underside of the composite body. As a result, the electrical contact pads of the optoelectronic semiconductor chip form electrical contacts of the optoelectronic component and enable electrical contacting of the optoelectronic component. The optoelectronic component may be suitable, for example, for surface mounting, for example, surface mounting by reflow soldering.
A top side of the optoelectronic semiconductor chip opposite the underside may be covered by the embedding material. Advantageously, this enables simple and cost-effective production of the optoelectronic component. Moreover, the embedding material covering the top side of the optoelectronic semiconductor chip may as a result also at least partly convert light emitted by the optoelectronic semiconductor chip into light comprising a different wavelength.
The optoelectronic component may comprise no further major component parts apart from the composite body. Advantageously, the optoelectronic component may comprise very compact external dimensions as a result.
A distance between the optoelectronic semiconductor chip and the reflector may be of identical magnitude on all sides of the optoelectronic semiconductor chip. In this example, the distance between the optoelectronic semiconductor chip and the reflector that is identical on all sides of the optoelectronic semiconductor chip is maintained within the scope of the production accuracy. A distance between the optoelectronic semiconductor chip and the reflector of the optoelectronic component that is identical on all sides of the optoelectronic semiconductor chip may advantageously support a particularly homogeneous light emission by the optoelectronic component.
The above-described properties, features and advantages and the way in which they are achieved will become clearer and more clearly understood in association with the following description of examples explained in greater detail in association with the drawings.
An adhesive film 110 is arranged at the top side 101 of the carrier 100. The adhesive film 110 may be, for example, an adhesive film releasable by thermal treatment or electromagnetic irradiation. In this example, the adhesiveness of the adhesive film 110 on one or on both sides of the adhesive film 110 may be reduced by a thermal treatment, for example, by heating or electromagnetic irradiation, for example, irradiation with UV light.
A structured reflector 200 has been arranged on the adhesive film 110 above the top side 101 of the carrier 100. The structured reflector 200 is formed as a thin, flat sheet or as a thin, flat film. The structured reflector 200 comprises a top side 201 and an underside 202 opposite the top side 201. The underside 202 of the structured reflector 200 faces the top side 101 of the carrier 100.
The structured reflector 200 may comprise a metal, for example. The structured reflector 200 may be formed, for example, as a metallic leadframe or as a metal film.
The structured reflector 200 comprises a plurality of openings 210 extending through the structured reflector 200. The openings 210 are preferably arranged in a regular arrangement, for example, in a regular matrix arrangement. As a result, the structured reflector 200 is formed as a grid.
The openings 210 may have been introduced into the structured reflector 200 by laser cutting, for example. In this example, the material of the structured reflector 200 was cut out in the region of the openings 210 by a laser beam. Structuring the reflector 200, that is to say creating the openings 210, may already have been carried out before arranging the structured reflector 200 above the top side 101 of the carrier 100.
The openings 210 may each comprise a rectangular, in particular a square, cross section. However, the openings 210 may, for example, also comprise circular-disk-shaped or other cross sections.
Optoelectronic semiconductor chips 300 have been arranged in the openings 210 of the structured reflector 200. The optoelectronic semiconductor chips 300 are configured to emit electromagnetic radiation, for example, visible light. The optoelectronic semiconductor chips 300 may be formed, for example, as light-emitting diode chips. By way of example, the optoelectronic semiconductor chips 300 may be formed as volume emitting light-emitting diode chips.
Each optoelectronic semiconductor chip 300 comprises a top side 301 and an underside 302 opposite the top side 301. The optoelectronic semiconductor chips 300 are configured to emit electromagnetic radiation at their top sides 301 during operation. In addition, the optoelectronic semiconductor chips 300 may also be configured to emit electromagnetic radiation at side faces extending between the top sides 301 and the undersides 302. In this example, electromagnetic radiation emitted at the side surfaces is emitted in a lateral direction.
The optoelectronic semiconductor chips 300 each comprise electrical contact pads 310 at their undersides 302. The optoelectronic semiconductor chips 300 may be formed, for example, as flip-chips, in particular, for example, as sapphire flip-chips. The electrical contact pads 310 of the optoelectronic semiconductor chips 300 make it possible to apply electrical voltage and electrical current to the optoelectronic semiconductor chips 300.
A respective optoelectronic semiconductor chip 300 has been arranged in each opening 210 of the structured reflector 200. The optoelectronic semiconductor chips 300 have been placed onto the adhesive film 110 in the openings 210 of the structured reflector 200. In this example, the optoelectronic semiconductor chips 300 have been arranged such that the undersides 302 of the optoelectronic semiconductor chips 300 face the top side 101 of the carrier 100. Arranging the optoelectronic semiconductor chips 300 in the openings 210 of the structured reflector 200 may have been carried out by a pick-and-place method, for example.
The optoelectronic semiconductor chips 300 each comprise, in a direction oriented perpendicularly to their top sides 301, a thickness measured from the top side 301 as far as the underside 302 which is larger than a thickness of the structured reflector 200 measured in a direction perpendicular to the top side 201 of the structured reflector 200 from the top side 201 as far as the underside 202. As a result, the optoelectronic semiconductor chips 300 arranged above the top side 101 of the carrier 100 in the openings 210 of the structured reflector 200 project beyond the top side 201 of the structured reflector 200.
It is expedient for the openings 210 of the structured reflector 200 to comprise a similar shape to the top sides 301 and undersides 302 of the optoelectronic semiconductor chips 300. In the example illustrated, both the openings 210 of the structured reflector 200 and the top sides 301 and undersides 302 of the optoelectronic semiconductor chips 300 comprise rectangular shapes. In this example, the openings 210 of the structured reflector 200 are somewhat larger than the top sides 301 and undersides 302 of the optoelectronic semiconductor chips 300. As a result, the optoelectronic semiconductor chips 300 arranged in the openings 210 of the structured reflector 200 are not in contact with the structured reflector 200. Rather, a distance 320 between the optoelectronic semiconductor chips 300 and the edges of the openings 210 of the structured reflector 200 results on all sides around the optoelectronic semiconductor chips 300. It is expedient for the distance 320 between the optoelectronic semiconductor chips 300 and the structured reflector 200 to be approximately of identical magnitude on all sides of the optoelectronic semiconductor chips 300. For this purpose, the optoelectronic semiconductor chips 300, within the scope of the achievable production accuracy, are positioned centrally in the openings 210 of the structured reflector 200.
Wavelength-converting films 410 have been arranged at the top sides 301 of the optoelectronic semiconductor chips 300 arranged above the top side 101 of the carrier 100. Arranging the wavelength-converting films 410 may have been carried out, for example, by laminating the wavelength-converting films 410 onto the top sides 301 of the optoelectronic semiconductor chips 300.
The wavelength-converting films 410 each comprise a wavelength-converting material. The wavelength-converting material of the wavelength-converting films 410 is configured to at least partly convert electromagnetic radiation emitted by the optoelectronic semiconductor chips 300 into electromagnetic radiation comprising a different wavelength. By way of example, the wavelength-converting material of the wavelength-converting films 410 may convert electromagnetic radiation emitted by the optoelectronic semiconductor chips 300 and comprising a wavelength from the blue or ultraviolet spectral range into yellow light. A mixture of unconverted light of the optoelectronic semiconductor chips 300 and light converted by the wavelength-converting material of the wavelength-converting films 410 may comprise a white light color, for example.
In the example shown in
The step of arranging the wavelength-converting films 410 may optionally be dispensed with. The further description of the production method will dispense with an illustration of the wavelength-converting films 410.
An embedding material 400 has been arranged above the top side 101 of the carrier 100. In this example, the optoelectronic semiconductor chips 300 were at least partly embedded into the embedding material 400. The structured reflector 200 was also at least partly embedded into the embedding material 400. A composite body 500 comprising the optoelectronic semiconductor chips 300, the structured reflector 200 and the embedding material 400 has been formed as a result.
If the wavelength-converting films 410 had been arranged on the top sides 301 of the optoelectronic semiconductor chips 300 in a previous processing step, then they would likewise have been embedded into the embedding material 400 and then likewise be part of the composite body 500.
Arranging the embedding material 400 above the top side 101 of the carrier 100 may have been carried out, for example, by a molding or casting process. A further processing step of curing the embedding material 400 may have been carried out after arranging the embedding material 400.
The top sides 301 of the optoelectronic semiconductor chips 300 are covered by the embedding material 400. However, it would also be possible for the top sides 301 of the optoelectronic semiconductor chips 300 not to be covered by the embedding material 400.
The composite body 500 formed by embedding the optoelectronic semiconductor chips 300 and the structured reflector 200 into the embedding material 400 comprises a top side 501 and an underside 502 opposite the top side 501. The top side 501 of the composite body 500 is formed by the embedding material 400. The underside 502 of the composite body 500 faces the top side 101 of the carrier 100 and is in contact with the adhesive film 110.
The embedding material 400 is at least partly transparent to electromagnetic radiation emitted by the optoelectronic semiconductor chips 300. The embedding material 400 may comprise a silicone, for example. In addition, the embedding material 400 may comprise embedded wavelength-converting particles. The wavelength-converting particles embedded into the embedding material 400 may be configured to at least partly convert electromagnetic radiation emitted by the optoelectronic semiconductor chips 300 into electromagnetic radiation comprising a different wavelength. By way of example, the wavelength-converting particles may be configured to convert electromagnetic radiation emitted by the optoelectronic semiconductor chips 300 and comprising a wavelength from the blue or ultraviolet spectral range into yellow light. A mixture of unconverted and converted light may comprise a white light color, for example. If wavelength-converting films 410 have been arranged at the top sides 301 of the optoelectronic semiconductor chips 300 in a preceding processing step, then wavelength-converting particles provided in the embedding material 400 may be dispensed with. Moreover, the wavelength-converting particles may be omitted if no wavelength converting is required.
The composite body 500 has been detached from the carrier 100. The adhesive film 110 has also been removed from the composite body 500. To remove the carrier 100 and the adhesive film 110 from the underside 502 of the composite body 500, an adhesiveness of the adhesive film 110 may have been reduced on one or on both sides of the adhesive film 110, for example, by a thermal treatment of the adhesive film 110 or an irradiation of the adhesive film 110 with electromagnetic radiation.
After detaching the composite body 500 from the carrier 100, the underside 502 of the composite body 500 is exposed. At the underside 502 of the composite body 500, the undersides 302 of the optoelectronic semiconductor chips 300 and the underside 202 of the structured reflector 200 terminate flush with one another. The undersides 302 of the optoelectronic semiconductor chips 300 and the underside 202 of the structured reflector 200 are not covered by the embedding material 400 and are thus exposed at the underside 502 of the composite body 500. As a result, the electrical contact pads 310 arranged at the undersides 302 of the optoelectronic semiconductor chips 300 are also exposed at the underside 502 of the composite body 500.
The composite body 500 has been divided into a plurality of parts each comprising an optoelectronic semiconductor chip 300. Each of these parts of the composite body 500 forms an optoelectronic component 10.
Dividing the composite body 500 may have been carried out by a sawing process, for example. In this example, the sawing cuts extend between the optoelectronic semiconductor chips 300 through the embedding material 400 and through the structured reflector 200.
The optoelectronic components 10 formed by dividing the composite body 500 each comprise no further major component parts or other housing parts apart from the respective part of the composite body 500.
The electrical contact pads 310 of the optoelectronic semiconductor chips 300 that are exposed at the undersides 302 of the optoelectronic semiconductor chips 300 form electrical contacts to electrically contact the optoelectronic components 10. The optoelectronic components 10 may be provided, for example, as SMD components for surface mounting, for example, for surface mounting by reflow soldering.
Our methods and components have been illustrated and described in greater detail on the basis of preferred examples. Nevertheless, this disclosure is not restricted to the examples disclosed. Rather, other variations may be derived therefrom by those skilled in the art, without departing from the scope of protection of the appended claims.
This application claims priority of DE 10 2016 112 293.9, the subject matter of which is incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2016 112 293.9 | Jul 2016 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/066792 | 7/5/2017 | WO | 00 |
