Optoelectronic Semiconductor Component and Method for Producing Same

Abstract

An optoelectronic semiconductor component and a method for producing the same are disclosed. In an embodiment the semiconductor component includes a semiconductor chip, which emits electromagnetic radiation of a first wavelength range from a radiation emission surface. The semiconductor component further includes a first conversion layer located on a lateral flank of the semiconductor chip, wherein the first conversion layer is suitable for converting electromagnetic radiation of the first wavelength range into electromagnetic radiation of a second wavelength range, and a second conversion layer located on the radiation emission surface of the semiconductor chip, wherein the second conversion layer is suitable for converting electromagnetic radiation of the first wavelength range into electromagnetic radiation of the second or of a third wavelength range. The first conversion layer is different from the second conversion layer.

Claims

1-15. (canceled)

17. A method for producing a plurality of optoelectronic semiconductor components the method comprising: applying a plurality of semiconductor chips, which emit electromagnetic radiation of a first wavelength range from a radiation exit surface during operation, onto an auxiliary carrier; applying a first conversion material into interstices between the semiconductor chips, wherein the first conversion material is suitable for converting electromagnetic radiation of the first wavelength range into electromagnetic radiation of a second wavelength range; applying a second conversion material over the first conversion material, wherein the second conversion material is suitable for converting electromagnetic radiation of the first wavelength range into electromagnetic radiation of a second wavelength range or of a third wavelength range; removing the auxiliary carrier; and singulating the semiconductor components, wherein the first conversion material forms a first conversion layer on lateral flanks of the semiconductor chips and the second conversion material forms a second conversion layer on the radiation exit surface of the semiconductor chips, wherein the first conversion material and the second conversion material are a first liquid resin and a second liquid resin into which phosphor particles have been introduced, and wherein the phosphor particles from the second resin sediment into the first resin, and wherein the first and second resins are cured before a singulation process.

18. The method according to claim 17, further comprising, before applying the first conversion material, applying a barrier around the semiconductor chips in a marginal region of the auxiliary carrier.

19. The method according to claim 17, further comprising, before applying the first conversion material, applying a reflective material into the interstices between the semiconductor chips.

20. The method according to claim 17, wherein removing the auxiliary carrier comprising removing the auxiliary carrier so that a back contact structure of the semiconductor chips is freely accessible and so that the contact structure is laterally expanded by applying a metallic structure.

21. The method according to claim 20, wherein the metallic structure is printed or applied using photolithography.

22. The method according to claim 17, further comprising placing geometric outcoupling structures onto a main surface of the second conversion layer facing away from the radiation exit surfaces of the semiconductor chips.

23. The method according to claim 17, further comprising applying a translucent layer onto the second conversion layer, wherein lateral flanks of the translucent layer are structured by the singulation process.

24. The method according to claim 17, further comprising determining in a simulation a concentration of phosphor particles in the first conversion material and a concentration of phosphor particles in the second conversion material.

25. The method according to claim 24, wherein determining in the simulation comprises: defining a color temperature of the electromagnetic radiation of the semiconductor component; defining the concentration of phosphor particles in the first conversion material; and determining the concentration of phosphor particles in the second conversion material using the color temperature and the concentration of phosphor particles in the first conversion material.

26. A semiconductor component comprising: a semiconductor chip configured to emit electromagnetic radiation of a first wavelength range from a radiation exit surface; a first conversion layer located on a lateral flank of the semiconductor chip, wherein the first conversion layer is suitable for converting electromagnetic radiation of the first wavelength range into electromagnetic radiation of a second wavelength range; and a second conversion layer located on a radiation exit surface of the semiconductor chip, wherein the second conversion layer is suitable for converting electromagnetic radiation of the first wavelength range into electromagnetic radiation of the second or of a third wavelength range, wherein the first conversion layer differs from the second conversion layer, wherein the first conversion layer is a resin comprising phosphor particles, and wherein a concentration of the phosphor particles exhibits a gradient along the lateral flank of the semiconductor chip.

27. The semiconductor component according to claim 26, wherein the semiconductor chip comprises a carrier and an epitaxial semiconductor layer sequence located thereon, wherein the epitaxial layer sequence comprises an active zone configured to generate electromagnetic radiation of the first wavelength range during operation, and wherein the semiconductor chip comprises a radiation exit surface formed by the main surface of the carrier, and wherein the radiation exist surface faces away from the epitaxial semiconductor layer sequence.

28. The semiconductor component according to claim 26, wherein the first conversion layer and the second conversion layer have different concentrations of phosphor particles.

29. The semiconductor component according to claim 26, wherein the second conversion layer is located directly on the radiation exit surface of the semiconductor chip and directly on the first conversion layer.

30. The semiconductor component according to claim 26, wherein two contact structures are arranged on a main surface opposite to the radiation exit surface, wherein the two contact structures are expanded by further metallic structures, and wherein the metallic structures extend to a side surface of the semiconductor component.

31. The semiconductor component according to claim 26, wherein a reflective layer is arranged on the lateral flank of the semiconductor chip, and wherein the reflective layer borders the main surface of the semiconductor chip opposite to the radiation exit surface.

32. The semiconductor component according to claim 31, wherein the reflective layer comprises a resin into which reflective particles have been introduced.

33. A semiconductor component comprising: a semiconductor chip configured to emit electromagnetic radiation of a first wavelength range from a radiation exit surface; a first conversion layer on a lateral flank of the semiconductor chip, wherein the first conversion layer is suitable for converting electromagnetic radiation of the first wavelength range into electromagnetic radiation of a second wavelength range; and a second conversion layer on the radiation exit surface of the semiconductor chip, wherein the second conversion layer is suitable for converting electromagnetic radiation of the first wavelength range into electromagnetic radiation of the second or of a third wavelength range, wherein the first conversion layer differs from the second conversion layer, wherein the first conversion layer comprises a resin having phosphor particles, wherein a concentration of the phosphor particles exhibits a gradient along the lateral flank of the semiconductor chip, wherein on the lateral flank of the semiconductor chip a reflective layer is arranged, and wherein the reflective layer borders the main surface of the semiconductor chip opposite to the radiation exit surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Further advantageous embodiments and developments of the invention result from the exemplary embodiments described below in conjunction with the figures.

[0054] By means of the sectional diagrams of FIGS. 1 to 4, a first exemplary embodiment of a method is described.

[0055] FIG. 5 shows a sectional diagram of a semiconductor component according to an exemplary embodiment.

[0056] By means of the sectional diagrams of FIGS. 6 to 8, a further exemplary embodiment of a method is described.

[0057] FIG. 9 shows a schematic sectional diagram of a semiconductor component according to an exemplary embodiment.

[0058] By means of the sectional diagrams of FIGS. 10 to 11 a further exemplary embodiment of a method is described.

[0059] FIG. 12 shows a sectional diagram of a semiconductor component according to an exemplary embodiment.

[0060] By means of the sectional diagrams of FIGS. 13 to 14 a further exemplary embodiment of a method is described.

[0061] FIG. 15 shows a sectional diagram of a semiconductor component according to an exemplary embodiment.

[0062] By means of the sectional diagrams of FIGS. 16 and 17, a simulation according to an exemplary embodiment for determining the phosphor concentration in one of the two conversion layers is explained in more detail.

[0063] FIGS. 18 to 22 show exemplary simulation results.

[0064] Like, identical or similar elements or elements having the same effect are provided with the same reference numbers in the figures. The figures and the size ratios to one another of the elements illustrated in the figures should not be considered as being to scale. Rather, to illustrate them better and/or to make them easier to understand, the size of individual elements, in particular layer thicknesses, may be exaggerated.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0065] In the method according to the exemplary embodiment of FIGS. 1 to 4, a plurality of semiconductor chips 1 are applied onto an auxiliary carrier 2 (FIG. 1). The semiconductor chips 1 comprise an epitaxial semiconductor layer sequence 3, which is applied onto a carrier 4. The epitaxial semiconductor layer sequence 3 comprises an active zone which generates electromagnetic radiation, in the present case blue light, during operation of the semiconductor chip 1.

[0066] The carrier 4 is configured to be radiation-transmissive, in particular for the light from the active zone. The carrier 4 is formed, e.g., from sapphire. The light that is generated in the active zone is emitted from a radiation exit surface 5 of the semiconductor chip 1, which is formed by a main surface of the carrier 4. Furthermore, light is also coupled out of the semiconductor chip from lateral flanks 6 of the carrier 4. The light from the active zone passes through the carrier 4 to its radiation exit surface 5 or to its lateral flanks 6 (see the arrows in FIG. 1).

[0067] On the main surface of the epitaxial semiconductor layer sequence 3, which faces away from the carrier 4, two contact structures 7 are applied, which are intended for the electrical contacting of the semiconductor chip 1.

[0068] In a next step, which is illustrated diagrammatically in FIG. 2, a barrier 8 is applied in an outer region of the auxiliary carrier 2. The barrier 8 in the present case is in an annular form and forms a closed contour around the semiconductor chips 1. The barrier in the exemplary embodiment of FIG. 2 is formed from silicone.

[0069] A first conversion material 9 is then introduced into the interstices between the semiconductor chips 1 and between the outermost semiconductor chip 1 and the barrier 8 (FIG. 3), e.g., by jetting or dispensing. The first conversion material 9 here is present as a liquid resin into which phosphor particles (not illustrated) have been introduced. The barrier 8 here prevents the first conversion material 9 from flowing off the auxiliary carrier 2. The first conversion material 9 extends as far as the radiation exit surface 5 of the semiconductor chips 1 and is flush with the radiation exit surface 5 of the semiconductor chips 1.

[0070] The phosphor particles of the first conversion material 9 are suitable for converting radiation from the semiconductor chip 1 of the first wavelength range into electromagnetic radiation of a second wavelength range. The second wavelength range in the present exemplary embodiment is yellow light.

[0071] In a next step, a second conversion material 10 is applied, which is suitable for at least partially converting radiation from the semiconductor chip 1 to another electromagnetic radiation (FIG. 4). For example, the second conversion material 10 also converts radiation from the semiconductor chip 1 to radiation of the second wavelength range. Furthermore, however, it is also possible that the second conversion material 10 converts the radiation from the semiconductor chip 1 to a third wavelength range which differs from that of the first and second wavelength ranges.

[0072] The second conversion material 10 here is applied over the entire surface of the composite composed of auxiliary carrier 2, semiconductor chips 1 and first conversion material 9. For example, the second conversion material 10 can be applied in liquid form by spray-coating. The second conversion material 10 here is present as a liquid resin into which phosphor particles have been introduced. The phosphor particles impart the wavelength-converting properties to the second conversion material 10.

[0073] Next, the resin of the first conversion material 9 and of the second conversion material 10 is cured and the auxiliary carrier 2 is removed. Finally, the semiconductor components are singulated, wherein the first conversion material 9 forms a first conversion layer 11 on the lateral flanks 6 of the semiconductor chip 1 and the second conversion material 10 forms a second conversion layer 12 on the radiation exit surface 5 of the semiconductor chip 1 (FIG. 5).

[0074] Alternatively, it is also possible that the second conversion material 10 is present as a conversion film, which is laminated on to the composite composed of first conversion material 11 and semiconductor chips 1. Before laminating the conversion film, the resin of the first conversion material 9 is cured. In this embodiment too, the auxiliary carrier 2 is removed and the semiconductor components singulated, wherein the first conversion material 9 forms a first conversion layer 11 on the lateral flanks 6 of the semiconductor chip 1 and the second conversion material 10 forms a second conversion layer 12 on the radiation exit surface 5 of the semiconductor chip 1.

[0075] The schematic sectional diagram of FIG. 5 shows a semiconductor component according to a first exemplary embodiment, as can be produced by the method according to the exemplary embodiment of FIGS. 1 to 4. The semiconductor component according to the exemplary embodiment of FIG. 5 comprises a semiconductor chip 1, on the radiation exit surface 5 of which the second conversion layer 12 is applied in direct contact therewith. The second conversion layer 12 projects laterally beyond the radiation exit surface 5 of the semiconductor chip 1 and covers the first conversion layer 11, which extends along the lateral flanks 6 of the semiconductor chip 1 to the contact structures 7.

[0076] Electromagnetic radiation which is generated in the active zone of the semiconductor chip 1 passes through the carrier 2 at least partially and is coupled out of the semiconductor chip 1 via the lateral flanks 6 of the carrier 2 or via its radiation exit surface 5. This outcoupled electromagnetic radiation then passes through the first conversion layer 11 or the second conversion layer 12 and is at least partially converted there to radiation of another wavelength range. Particularly preferably, the conversion layers 11, 12 are formed such that they convert part of the blue light from the active zone to yellow light, so that the entire semiconductor component emits white light.

[0077] In the method according to the exemplary embodiment of FIGS. 6 to 8, in contrast to the method according to FIGS. 1 to 4, before applying the first conversion material 9 a reflective material 13 is applied into the interstices between the semiconductor chips 1 on the auxiliary carrier 2. The reflective material 13 here is likewise initially configured in liquid form. It is formed from a resin into which reflective particles have been introduced. The reflective material 13 can also be introduced into the interstices, e.g., by dispensing or pouring (see FIG. 6).

[0078] In a next step, which is illustrated schematically in FIG. 7, the first conversion material 9 is then applied in liquid form onto the reflective material 13. Particularly preferably here, the reflective material 13 is cured before applying the first conversion material 9.

[0079] A second conversion material 10 is then applied onto the first conversion material 9 and the semiconductor chips 1, as already described by means of FIG. 4 (FIG. 7).

[0080] Finally, the auxiliary carrier 2 is removed and the semiconductor components are singulated (not illustrated).

[0081] In the method according to the exemplary embodiment of FIGS. 6 to 8, a semiconductor component as illustrated diagrammatically, e.g., in FIG. 9 can be produced.

[0082] In contrast to the semiconductor component according to the exemplary embodiment of FIG. 5, the semiconductor component according to the exemplary embodiment of FIG. 9 comprises a reflective layer 14, which partially covers the lateral flanks 6 of the semiconductor chip 1. The reflective layer 14 is arranged on the region of the lateral flanks 6 of the semiconductor chip 1 which borders the contact structures 7.

[0083] The first conversion layer 11, which is flush with the radiation exit surface 5 of the semiconductor chip 1, has been applied onto the reflective layer 14 in direct contact therewith. The second conversion layer 12 has in turn been applied on to the first conversion layer 11 and the radiation exit surface 5 of the semiconductor chip 1, as already described with the aid of FIG. 5.

[0084] In the method according to the exemplary embodiment of FIGS. 10 and 11, the method steps as already described with the aid of FIGS. 1 to 4 are initially carried out. The resin of the conversion layers 11, 12 is then cured and the auxiliary carrier 2 removed (FIG. 10). Metallic structures 15 are then applied on to the main surface of the composite composed of first conversion layer 11 and semiconductor chip 1, which is exposed by removing the auxiliary carrier 2, on to the contact structures 7 (FIG. 11). The metallic structures 15 here expand the contact structures 7 laterally.

[0085] The semiconductor component according to the exemplary embodiment of FIG. 12 can be produced, e.g., by the method as described with the aid of FIGS. 10 and 11. In contrast to the semiconductor component as already described with the aid of FIG. 5, in the semiconductor component according to FIG. 12, a metallic structure 15 is arranged on each contact structure 7, which in each case projects laterally beyond the semiconductor chip 1 and extends to a side surface of the semiconductor component. With the aid of the metallic structures 15, better electrical contacting of the semiconductor chip 1 is possible.

[0086] FIG. 13 shows in diagrammatic form a method step as can be carried out, e.g., by the method step as already described with the aid of FIG. 4. In the method step according to the exemplary embodiment of FIG. 13, on the cured second conversion material 10, a translucent layer 16 is applied over the entire surface. The translucent layer 16 is formed, e.g., from silicone or glass. In a next step, the semiconductor components are singulated, wherein, for example, the lateral flanks of the translucent layer 16 are beveled using an appropriate saw blade (FIG. 14). The translucent layer 16 with the beveled side surfaces improves the outcoupling of light from the finished semiconductor component.

[0087] The semiconductor component according to the exemplary embodiment of FIG. 15, in contrast to the semiconductor component according to FIG. 5, comprises outcoupling structures 17, which are placed on the second conversion layer 12. The outcoupling structures 17 likewise improve the outcoupling of light from the semiconductor component.

[0088] FIG. 16 shows a schematic diagram of a device on which the simulation to determine the concentration of phosphor particles in the first conversion layer 11 and second conversion layer 12 can be based.

[0089] The device according to the exemplary embodiment of FIG. 16 comprises a reflective base plate 18 with a reflectance of R=0.95. A semiconductor chip 1 with edge lengths of 1 mm.sup.2 each is applied on the base plate 18. The semiconductor chip 1 is a flip-chip.

[0090] A high-refractive index (HRI) lens 19 is arranged over the semiconductor chip 1. In each of two corners of the base plate, an electrical connection point 20 is formed which in the present case comprises or is formed from gold.

[0091] A flip-chip like that on which the simulation is based is illustrated schematically in FIG. 17. The flip-chip comprises a carrier 4 composed of sapphire with a thickness of about 115 micrometers. Furthermore, the epitaxial semiconductor layer sequence 3 of the semiconductor chip comprises an n-conducting GaN layer 21 and a p-conducting GaN layer 22 with a refractive index of about 2.5 in each case. The absorption coefficient of the n-conducting GaN layer 21 is assumed to be 1/cm and the absorption coefficient of the p-conducting GaN layer 22 is assumed to be 30/cm.

[0092] Within the epitaxial semiconductor layer sequence 3, mallets 23, which comprise an inner electrically conductive layer and an outer electrically insulating layer, are provided for electrical contracting. The electrically insulating layer can comprise or be formed from, e.g., one of the following materials: silicon oxide, silicon nitride. The electrically conductive layer can comprise or be formed from, e.g., one of the following materials: titanium, silver.

[0093] On the epitaxial semiconductor layer sequence 3 a mirror layer (not illustrated) is arranged. The mirror layer in the simulation has a reflectance of approximately 0.97. The mirror layer can be designed to be electrically conducting or electrically insulating.

[0094] Finally, the contact structures 7 are formed, e.g., from silver and have a reflectance of about 0.9.

[0095] In the simulation, a fixed color temperature is initially preset for the mixed-colored light which the semiconductor component is intended to emit, and which is composed of unconverted electromagnetic radiation from the semiconductor chip and converted radiation from the conversion layers. For example, the color temperature of the mixed-colored light in the simulation is 6000 K.

[0096] The thickness of the first conversion layer 11 and the thickness of the second conversion layer 12 are each set at, e.g., 50 micrometers, while the concentration of phosphor particles in the second conversion layer 12 is variable. In both conversion layers 11, 12, a garnet phosphor such as YAG:Ce, for example, is used as a phosphor.

[0097] Now, during a first simulation the concentration of the phosphor particles in the first conversion layer 11 is kept constant and the concentration of phosphor particles in the second conversion layer 12 is determined iteratively for a color temperature of 6000 K. The simulation is repeated for various concentrations of phosphor particles in the second conversion layer 12, namely c.sub.0=0 wt. %, c.sub.1=10 wt. %, c2=20 wt. %, c3=30 wt. %, c4=40 wt. %, c5=50 wt. % and c6=60 wt. %.

[0098] FIG. 18 shows, as a result of the simulation, the luminous intensity I.sub.V as a function of the solid angle Ω at various concentrations of phosphor in the first conversion layer 11. The concentrations of phosphor particles in the first conversion layer 11 are: in the curve I.sub.0 0 wt. %, in the curve I.sub.1 10 wt. %, in the curve I.sub.220 wt. %, in the curve I.sub.3 30 wt. %, in the curve I.sub.4 40 wt. %, in the curve I.sub.5 50 wt. % and in the curve I.sub.6 60 wt. %. The average full width at half maximum (FWHM) of the curves I.sub.0 to I.sub.6 is approximately 155°.

[0099] FIG. 19 shows the simulation results for the color coordinate C.sub.Y as a function of the angle Ω. The curves are again determined assuming various concentrations of phosphor in the first conversion layer 11. The concentrations of phosphor particles in the first conversion layer 11 are: in the curve C.sub.y0 0 wt. %, in the curve C.sub.y1 10 wt. %, in the curve C.sub.y2 20 wt. %, in the curve C.sub.y3 30 wt. %, in the curve C.sub.y4 40 wt. %, in the curve C.sub.y5 50 wt. % and in the curve C.sub.y6 60 wt. %. The simulation shows that, as the concentration of phosphor particles in the first conversion layer 11 increases, a blue ring in an outer region of the emission cone of the mixed-colored light as well as a yellowish center of the emission cone of the mixed-colored light become smaller (see arrows). At a concentration of phosphor particles of between 50% and 60%, the semiconductor component according to the simulation exhibits an optimized color impression across the solid angle.

[0100] FIG. 20 shows a simulation result of the luminous flux Φ.sub.V at a color temperature of 6000 K as a function of the concentration of phosphor particles c in the first conversion layer 11. FIG. 20 shows that the efficiency of the semiconductor component is better if the lateral flanks 6 of the semiconductor chip 1 are covered with phosphor particles. The efficiency is increased by approximately 2%.

[0101] FIG. 21 shows the concentration C.sub.top of phosphor particles in the second conversion layer 12 on the radiation exit surface 5 of the semiconductor chip 1 as a function of the concentration C.sub.side of phosphor particles in the first conversion layer 11 on the lateral flank 6 of the semiconductor chip 1 for a preset color temperature of the mixed-colored light emitted by the semiconductor component of 6000 K.

[0102] FIG. 22 shows the ratio of the concentration of phosphor particles in the first conversion layer to the concentration of phosphor particles in the second conversion layer C.sub.side/C.sub.top as a function of the color coordinate ΔC.sub.Y. The color coordinate ΔC.sub.Y is the difference between the color coordinate C.sub.Y at 0° and the color coordinate at 85″. In other words, the value ΔC.sub.Y is a measure of the dependence of the color location on angle.

[0103] The description with the aid of the exemplary embodiments does not limit the invention thereto. Rather, the invention comprises any new feature and any combination of features, which in particular includes any combination of features in the patent claims, even if this feature or this combination is not itself explicitly stated in the patent claims or exemplary embodiments.