Optical Component, Optoelectronic Semiconductor Component and Method for Producing an Optical Component

Abstract

In an embodiment an optical component includes an optical body at least partially translucent to visible light and a coating directly arranged at the optical body, wherein the coating has a reflection coefficient of at least 0.8 for at least one wavelength range in a range from 380 nm to 1500 nm and an average thickness between 10 μm and 200 μm inclusive, wherein the coating has a polysiloxane as base material, and wherein the polysiloxane comprises —SiO.sub.3/2 units.

Claims

1.-16. (canceled)

17. An optical component comprising: an optical body at least partially translucent to visible light; and a coating directly arranged at the optical body, wherein the coating has a reflection coefficient of at least 0.8 for at least one wavelength range in a range from 380 nm to 1500 nm and an average thickness between 10 μm and 200 μm inclusive, wherein the coating has a polysiloxane as base material, and wherein the polysiloxane comprises —SiO.sub.3/2 units.

18. An optoelectronic semiconductor component comprising: at least one optical component according to claim 17; and at least one radiation-emitting optoelectronic semiconductor chip, the at least one optoelectronic chip configured to emit radiation, wherein the at least one optical component is attached to the at least one optoelectronic semiconductor chip, and wherein the optical component is configured to emit the radiation out of the semiconductor component at least partially through the optical component.

19. A method for producing an optical component, the method comprising: providing a plurality of optical bodies at least partially translucent to visible light; applying a liquid coating material directly to the optical bodies; solidifying the coating material to form a coating; and separating through the coating the optical components, wherein the finished coating has an average thickness between 10 μm and 200 μm inclusive, wherein the finished coating comprises a polysiloxane as base material, wherein the polysiloxane comprises —SiO.sub.3/2 units, and wherein the method is performed in the order indicated.

20. The method according to claim 19, further comprising: applying a temporary mask to top faces of the optical bodies after providing the plurality of optical bodies and before applying the liquid coating material; wherein providing the plurality of optical bodies comprises applying rear sides of the optical bodies to a carrier, the top faces being opposite the rear sides; removing the mask after applying the liquid coating material; and completely removing the carrier after forming the coating.

21. The method according to claim 20, wherein the optical bodies taper in a direction towards the top face.

22. The method according to claim 19, wherein only side surfaces of the optical bodies are provided with the coating material and thus with the coating.

23. The method according to claim 19, wherein the finished coating exhibits a transmission coefficient for visible light of at most 0.05 and a reflection coefficient of at least 0.8.

24. The method according to claim 19, wherein the coating material and the coating comprise scattering particles embedded in the base material, wherein the scattering particles have a larger refractive index than the base material, wherein an average diameter of the scattering particles is between 0.15 μm and 0.5 μm, inclusive, and wherein a weight fraction and/or a volume fraction of the scattering particles in the coating material is between 40% and 70%, inclusive.

25. The method according to claim 19, wherein the optical body is a luminescent body configured to partially or completely convert a short wavelength radiation incident on or passing through the optical body into a longer wavelength radiation.

26. The method according to claim 25, wherein the optical body comprises or is a ceramic body and the ceramic body includes at least one phosphor, and wherein the at least one phosphor is configured to generate green, yellow, orange and/or red light from blue light and/or from ultraviolet radiation.

27. The method according to claim 19, further comprising: attaching radiation-emitting optoelectronic semiconductor chips on the coated optical bodies after forming the coating.

28. The method according to claim 19, further comprising: producing a cladding on the coating after forming the coating, wherein the finished cladding has an average layer thickness greater by at least a factor of three than the finished coating, and wherein the cladding comprises a further polysiloxane as a further base material.

29. The method according to claim 19, wherein an average lateral extent of the optical bodies, as seen in plan view, is between 0.2 mm and 2 mm, inclusive, wherein an average thickness of the optical bodies is between 30 μm and 2 mm, inclusive, and wherein the finished coating is thinner than the optical bodies.

30. The method according to claim 19, wherein, taken together, at least 80% of base units of the polysiloxane of the finished coating are formed by —SiO.sub.3/2 units and by —SiO.sub.4/2 units, and wherein a proportion of the —SiO.sub.3/2 units exceeds a proportion of the —SiO.sub.4/2 units.

31. The method according to claim 30, wherein at least 70% of the base units of the polysiloxane of the finished coating are —SiO.sub.3/2 units, and wherein organic residues on the —SiO.sub.3/2 units are predominantly formed by phenyl groups and/or by methyl groups.

32. The method according to claim 19, wherein, while forming the coating, a loss in mass of the coating material, in terms of a hydrolyzable volatile organic content, is between 10% and 35%, inclusive, and wherein the solidifying includes a final curing at a temperature between 150° C. and 250° C., inclusive, for a duration of between 2 h and 24 h, inclusive.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] In the following, an optical component described herein, an optoelectronic semiconductor component described herein and a method described herein are explained in more detail with reference to the drawing on the basis of exemplary embodiments. Identical reference signs indicate identical elements in the individual figures. However, no references to scale are shown, rather individual elements may be shown exaggeratedly large for better understanding.

[0075] It shows:

[0076] FIGS. 1, 3, 5, 7, 8, 9, and 10 schematic cross-sectional views of an exemplary embodiment of a method for producing optoelectronic semiconductor components;

[0077] FIGS. 2, 4 and 6 schematic top views of the method steps of FIGS. 1, 3 and 5;

[0078] FIGS. 11, 13 and 15 schematic sectional views of method steps of an exemplary embodiment of a further method;

[0079] FIGS. 12, 14 and 16 schematic top views of the method steps of FIGS. 11, 13 and 15;

[0080] FIG. 17 a schematic structural formula for an example of a base material of a coating ; and

[0081] FIG. 18 a schematic representation of an internal structure of an example.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0082] FIGS. 1 to 10 show an exemplary embodiment of a process of production for optical components 23 and for optoelectronic semiconductor components 1. In the method step of FIGS. 1 and 2, a plurality of optical bodies 2 are provided. The optical bodies 2 are located with rear sides 21 on a temporary carrier 51, and top faces 22 of the optical bodies 2 face away from the carrier 51.

[0083] For example, the optical body 2, which is transparent in particular, tapers in the direction away from the carrier 51. That is, side surfaces 20 of the optical body 2, as seen in cross section, approach each other in the direction away from the carrier 51. For example, each side surface 20, as seen in cross-section, has one or more sections that merge into one another with a kink. For example, viewed in cross-section, the optical body 2 is formed from a rectangle followed by a symmetrical trapezoid.

[0084] Seen in top view, the optical bodies 2 are, for example, square or rectangular in shape and are preferably arranged in a regular grid on the carrier 51.

[0085] Preferably, the top faces 22 of the optical bodies 2 are covered by a temporary mask 52. This means that only the side surfaces 20 are exposed. The mask 52 is formed, for example, by a photoresist or also by a hard mask, for example of stainless steel.

[0086] In the method step of FIGS. 3 and 4, it is shown that a coating material 30 is applied over the entire surface. The coating material 30 is sprayed on, for example. Preferably, the coating material 30 is deposited with a uniform thickness in particular on the side surfaces 20 and optionally also on the mask 52 and on the carrier 51 in areas between the optical bodies 2. The coating 30 is applied in a liquid state.

[0087] In the method step of FIGS. 5 and 6, it can be seen that the temporary mask 52 has been removed. This exposes the top faces 22. Solidifying of the coating material 30 results in a coating 3 that covers the side surfaces 20 with a uniform thickness all around. Solidifying can be performed in multiple steps and is preferably performed after removal, or alternatively before removal of the mask 52.

[0088] Examples of the formulation of the coating material 30 are the materials KR-220L, KR-500, KR-213, KR-510, X-40-9227, KR-9218, KR-401N, X-40-2756 or X-40-2667A from the manufacturer Shin-Etsu. Furthermore, the materials Silres SY231 or Silres IC368 from the manufacturer Wacker or silicophene types from the manufacturer Evonik, for example AC1000, can be used as coating material 30. With regard to the coating material 30, reference is also made to the publication US 2012/0058333 A1. The disclosure content of this publication, in particular paragraphs 29, 30, 31, 35, 36, 43, 50, 64 and 65 and claim 1, is incorporated by reference. Particles, such as reflective particles, are preferably added to the coating material 30 in each case. The foregoing applies in like manner to all other exemplary embodiments.

[0089] Preferably, the processing of the coating material 30 into the coating 3 is carried out as intended for the exemplary mentioned materials. In particular, solidifying the coating material 30 into the coating 3 comprises a temperature treatment, for example at about 200° for about 10 hours. In particular, the solidification of the coating material 30 is based on hydrolysis.

[0090] As is also possible in all other exemplary embodiments, the coating 3 has a glass-like consistency after complete solidification and is thus comparatively brittle. However, since the coating 3 has only a small thickness, preferably about 50 μm, negative influences of the brittleness of the coating 3 can be reduced.

[0091] In the method step of FIG. 7, a single resulting optical component 23 comprising the optical body 2 and the coating 3 is shown. The rear side 21 as well as the top face 22 are free of the preferably reflective, white coating 3.

[0092] As in all other embodiments, it is possible that the optical body 2 specifically intended for light concentration is formed of a glass or also of another light-transmitting material such as sapphire or silicon carbide. It is also possible that the optical body 2 contains a phosphor.

[0093] In the step of FIG. 8, it is shown that the optical components 23 are applied to optoelectronic semiconductor chips 4, in particular to LED chips. This is optionally done on a further carrier 53, on which the optoelectronic semiconductor chips 4 can be mounted in a regular grid.

[0094] It is shown, see FIG. 8, left half, that the coating 3 projects laterally beyond the associated semiconductor chip 4 so that the optical body 2 is flush with the semiconductor chip 4 in the lateral direction. That is, a top face of the semiconductor chip 4 facing away from the further carrier 53 can be completely or substantially completely covered by the optical body 2.

[0095] Side surfaces of the semiconductor chip 4 that run transversely to its top face are preferably free of the optical body 2 and/or the coating 3.

[0096] In contrast, it can be seen in FIG. 8, right side, that the optical component 23 is overall flush or approximately flush with the semiconductor chip 4 in the lateral direction. That is, a top face of the semiconductor chip 4 facing away from the further carrier 53 is covered by the optical body 2 together with the coating 3.

[0097] Corresponding configurations, as shown in FIG. 8, can be present in the same way in all other exemplary embodiments.

[0098] In the optional method step of FIG. 9, it can be seen that an cladding 6 is created around the semiconductor chips 4 and around the optical components 23. The cladding 6 can be flush with the top faces 22 in the direction away from the further carrier 53. The cladding 6 is preferably a comparatively thickly applied potting compound and is in particular made of a relatively soft, further polysiloxane.

[0099] Also illustrated in FIG. 9, see the left side, is that the optical component 23 may include a luminescent body 7 in addition to the optical body 2. The luminescent body 7 comprises one or more phosphors, which may be embedded in a matrix material, for example a glass or ceramic or a third polysiloxane, or the luminescent body 7 may consist of one or more phosphors. Preferably, both the luminescent body 7 and the optical body 2 are completely coated on the side with the coating 3.

[0100] In contrast, it can be seen in FIG. 9, right half, that the separate luminescent body 7 is located between the semiconductor chip 4 and the optical component 23.

[0101] In particular, the top face 22 is free of the cladding 6. For example, the cladding 6 is arranged exclusively on a side of the coating 3 facing away from the optical body 2 and on side surfaces of the semiconductor chip 4.

[0102] These two configurations, as shown in FIG. 9, can be used in the same way in all other exemplary embodiments.

[0103] The semiconductor chip 4, the optional luminescent body 7 and the optical component 23 are bonded to one another, for example, in particular by means of a silicone adhesive, not shown. Electrical contacts of the semiconductor chips 4, not shown, are preferably each facing the further carrier 53 and thus facing away from the optical component 23. Alternatively, it is possible, not shown, for the optical component 23 and optionally the luminescent body 7 to have recesses to enable electrical contacting of the semiconductor chip 4.

[0104] FIG. 10 shows the finished optoelectronic semiconductor component 1, which is obtained by separating the configuration of FIG. 9. Seen in cross-section, the semiconductor component 1 may be cuboidal.

[0105] As in all other exemplary embodiments, the coating 3 preferably has an average thickness C of approximately 50 μm. An average thickness T of the optical bodies 2 and the optical components 23 is, for example, in the range of 0.2 mm to 0.5 mm. A lateral extension D of the semiconductor chip 4 and thus also of the optical body 2 and the optical component 23 is approximately 1 mm. The optionally present cladding 6 is significantly thicker than the coating 3 and, unlike the coating 3, can be understood as a bulk material.

[0106] Furthermore, it can be seen from FIG. 10 that radiation R generated during operation of the semiconductor chip 4 can only leave the semiconductor component 1 through the optical component 23. It is possible that the further carrier 53 has been removed from the semiconductor chips 4 and the cladding 6. Alternatively, the further carrier 53 may remain in separated form on the semiconductor chip 4 and on the optional cladding 6, other than as illustrated in FIG. 10.

[0107] In summary, in the method according to FIGS. 1 to 10, the future optical components 23 are first produced using a layering process or a surface process, for example by means of spraying, doctor blading, screen printing or slot coating. Subsequently, the coating is applied in particular directly to the optical body 2 and optionally also to the temporary carrier 51, followed by a separation into discrete optical components 23. After this step, there is preferably an expansion of the temporary carrier material 51, which is for example a film, in order to achieve the necessary spacing, in particular a double target layer thickness of the optional cladding 6, between the optical components. However, a separate pick-and-place process is also conceivable.

[0108] In the method of FIGS. 11 to 16, an initial layer 2′ is applied to the carrier 51 for the optical bodies 2, see FIGS. 11 and 12.

[0109] Subsequently, see FIGS. 13 and 14, the initial layer 2′ is patterned to form the optical bodies 2.

[0110] In this case, the optical bodies 2 are preferably fluorescent bodies 7. Deviating from the illustration of FIG. 13, it is not mandatory that the optical bodies 2 are rectangular or approximately rectangular when viewed in cross-section. Geometries, as shown for example in connection with FIGS. 1 to 10, can also be used for the optical bodies 2.

[0111] FIGS. 15 and 16 show that the coating material 30 for the coating 3 is applied only between the optical bodies 2.

[0112] Via capillary forces and/or surface properties, it is possible that the coating 3 between the optical bodies 2 has a paraboloid top face when viewed in cross-section. Separation lines S run between adjacent optical bodies 3 in the area of the coating 3 for a subsequent separation, which is carried out by means of laser radiation, for example.

[0113] The methods steps of FIGS. 7, 8, 9 and/or 10 can follow the method of FIGS. 11 to 16 in a correspondingly adapted manner.

[0114] In the method of FIGS. 11 to 16 in particular, the coating material is filled into the spaces formed between the optical bodies 2 to produce the lateral coating, for example by means of jetting or needle dispensing, if necessary using capillary force. The thin layer thus formed, which may have a groove-like shape, is cured, separated and the processed optical components 23 can be further processed accordingly, for example by pick-and-place methods. Application of the coating material 30 is also possible by means of a screen printing process in connection with FIGS. 11 to 16, if necessary with suitable masking by means of a screen and/or by means of a protective film for the light exit surfaces of the optical bodies 2, instead of by means of a dosing process.

[0115] The corresponding method steps for applying and solidifying the coating material, as illustrated in FIGS. 3 to 6 or 13 to 16, may be repeated or combined until the desired layer thickness for the coating 3 is achieved. That is, as in all other exemplary embodiments, the coating 3 may be composed of a plurality of sub-layers, each of which is produced by applying a thinner sub-layer of the coating material 30.

[0116] Optionally, a plasma step is performed between the application of each of the partial layers in order to improve adhesion to the next partial layer to be applied. Such a plasma step can also be carried out before generating the cladding 6, in order to ensure improved adhesion of the cladding 6 to the coating 3. Such plasma steps are possible in all exemplary embodiments.

[0117] In FIG. 17, schematically an exemplary structural formula of the finished coating 3 is shown, whereby optionally additionally present particles are not drawn. It can be seen from FIG. 17 that the polysiloxane is predominantly composed of T units, so that there are usually three oxygen atoms attached to the silicon atoms. There may also be some Q units, in which four oxygen atoms are attached to each silicon atom. In addition, so-called D units, i.e. —SiO.sub.2/2 units, can be present, in which two oxygen atoms are assigned to one silicon atom.

[0118] The residues R can all be of the same design or different residues R are present. Preferably, the residues R are organic residues, in particular alkyl groups and/or aryl groups. For example, the residues R are formed by methyl groups and/or by phenyl groups.

[0119] In FIG. 18, an example of a section of a coating 3 is shown. In order to produce coatings 3 that are almost opaque and preferably have a high reflectivity for visible light, the coating 3 has the polysiloxane with the high proportion of T units as the base material 31, for example as illustrated in FIG. 17. Particles 32 are embedded in the base material 31. The particles 32 are preferably metal oxide particles such as titanium dioxide particles, which act as a scattering center for electromagnetic radiation in the wavelength range in particular from 380 nm to 1500 nm, preferably 430 nm to 780 nm.

[0120] Preferably, the particles 32 are present individually in the base material 31. Alternatively, it is possible for a small proportion of the particles 32 to be agglomerated such that a plurality of the particles 32 are directly adjacent to each other. In order to achieve high reflectivity, a weight fraction and/or a volume fraction of the particles 32 is preferably set comparatively high, whereby significant agglomeration of particles is preferably avoided.

[0121] The components shown in the figures preferably follow one another in the sequence indicated, in particular immediately one after the other, unless otherwise described. Layers that do not touch in the figures are preferably spaced apart. Insofar as lines are drawn parallel to one another, the associated surfaces are preferably likewise aligned parallel to one another. Furthermore, the relative positions of the drawn components to each other are correctly reproduced in the figures, unless otherwise described.

[0122] The invention described herein is not limited by the description based on the exemplary embodiments. Rather, the invention encompasses any new feature as well as any combination of features, which in particular includes any combination of features in the patent claims, even if this feature or combination itself is not explicitly stated in the patent claims or exemplary embodiments.