Method for Producing an Optoelectronic Component, and Optoelectronic Component

Abstract

A method for producing an optoelectronic component and an optoelectronic component are disclosed. In an embodiment a method includes providing a carrier having a pedestal with a support surface, applying a liquid joining material with filler particles to the support surface of the pedestal and applying a radiation emitting semiconductor chip with a mounting surface, which is larger than the support surface of the pedestal to the liquid joining material such that the joining material forms a joining layer between the support surface of the pedestal and the mounting surface of the semiconductor chip and the joining material at least partially fills only a recess, which is limited by a part of the mounting surface projecting beyond the support surface.

Claims

1-18. (canceled)

19. A method for manufacturing an optoelectronic component, the method comprising: providing a carrier having a pedestal with a support surface; applying a liquid joining material with filler particles to the support surface of the pedestal; and applying a radiation emitting semiconductor chip with a mounting surface, which is larger than the support surface of the pedestal to the liquid joining material such that the joining material forms a joining layer between the support surface of the pedestal and the mounting surface of the semiconductor chip and the joining material at least partially fills only a recess, which is limited by a part of the mounting surface projecting beyond the support surface, wherein a surface of the carrier is covered with the joining material only below the mounting surface of the semiconductor chip while a remainder of the surface of the carrier remains free of the joining material, and wherein the filler particles are diffusively reflective at least for an electromagnetic radiation of an active zone.

20. The method according to claim 19, wherein the semiconductor chip is applied to the support surface by lowering such that the joining material completely wets the mounting surface of the semiconductor chip before filling the recess.

21. The method according to claim 19, wherein the carrier comprises a lead frame.

22. The method according to claim 19, wherein the semiconductor chip comprises an epitaxial semiconductor layer sequence having the active zone configured to generate the electromagnetic radiation of a first wavelength range and a substrate transparent for the electromagnetic radiation of the active zone.

23. The method according to claim 19, wherein the joining layer has a thickness between 1 micrometers and 5 micrometers inclusive.

24. The method according to claim 19, wherein the filler particles have a diameter between 150 nanometer and 250 nanometer inclusive.

25. The method according to claim 19, wherein a surface of the carrier at least partially forms a bottom surface of a cavity, in which the semiconductor chip is arranged, and wherein the cavity is filled with a casting, in which phosphor particles are introduced, which are configured to convert the radiation of a first wavelength range into radiation of a third wavelength range.

26. An optoelectronic component comprising: a carrier comprising a pedestal having a supporting surface; a radiation emitting semiconductor chip having a mounting surface larger than the support surface of the pedestal so that a recess is defined by a part of the mounting surface projecting beyond the support surface; a joining layer comprising a joining material with filler particles and connecting the mounting surface of the semiconductor chip and the support surface of the pedestal to one another in a material-locking manner; and an underfill formed from the joining material with the filler particles and arranged only in the recess while a region of a surface of the carrier, which is not protruded by the semiconductor chip is free of the underfill, and wherein the filler particles are diffusively reflective at least for an electromagnetic radiation of an active zone.

27. The optoelectronic component according claim 26, wherein side surfaces of the semiconductor chip are free of the joining material.

28. The optoelectronic component according to claim 26, wherein the component is configured to emit warm white light.

29. The optoelectronic component according to claim 26, wherein the carrier has a single pedestal and the semiconductor chip is applied centrally to the support surface of the pedestal so that the recess is formed completely circumferentially around the pedestal.

30. The optoelectronic component according to claim 26, wherein the pedestal has an protrusion or indentation delimited by the support surface.

31. The optoelectronic component according to claim 26, wherein the semiconductor chip has two electrical contacts on a front side of the semiconductor chip, and wherein the carrier has two pedestals, each pedestal is arranged below an electrical contact of the semiconductor chip.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Further advantageous embodiments and developments of the invention result from the execution examples described in the following in connection with the Figures.

[0037] On the basis of the schematic sectional views of FIGS. 1 to 7, a method according to an execution example is explained in more detail.

[0038] On the basis of the schematic sectional views of FIGS. 8 to 11, a method according to a further execution example is explained in more detail.

[0039] The schematic sectional views of FIGS. 12 and 13 each show an optoelectronic component according to an execution example.

[0040] Same, similar or similarly acting elements are provided in the Figures with the same reference signs. The Figures and the proportions of the elements depicted in the Figures are not to be regarded as true to scale. Rather, individual elements, in particular layer thicknesses, can be exaggeratedly large for better representability and/or better understanding.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0041] In the method according to the execution example of FIGS. 1 to 7, a carrier 1 is provided in a first step (FIG. 1). At present, the carrier 1 comprises a metallic lead frame 2 and a housing body 3. The lead frame 2 is inserted into the housing body 3 and in places forms a surface of the carrier 1. The lead frame 2 has a pedestal 4 with a supporting surface. The housing body 3 forms a cavity 5 with a bottom surface, whereby the bottom surface of the cavity 5 is formed in places by the surface of the lead frame 2. Furthermore, pedestal 4 in cavity 5 is freely accessible from the outside.

[0042] The next step a drop of liquid jointing material 6 is applied to the support surface of the pedestal 4. At present, the jointing material 6 has reflective filler particles. The liquid joining material 6 completely wets the supporting surface, while the side surfaces of the pedestal 4 and the remaining surface of the carrier 1 are free of the joining material 6. Then a radiation emitting semiconductor chip 7, for example in a pick-and-place process, is positioned above the pedestal 4 with the joining material 6 (FIG. 2)

[0043] The semiconductor chip 7 has an epitaxial semiconductor layer sequence 8 with an active zone 9 that is configured to generate blue light. The epitaxial semiconductor layer sequence 8 is grown epitaxially on a first main surface of a substrate 10. The substrate is a sapphire substrate that is transparent to the blue light of the active zone 9. The first main surface of the substrate 10 is opposed by a second main surface of the substrate 10, which forms the mounting surface of the semiconductor chip 7. The semiconductor chip 7 emits the light generated by the active zone 9 via its radiation exit surface, which is opposite the mounting surface. Furthermore, the semiconductor chip 7 comprises two front electrical contacts 11.

[0044] In a next step, the semiconductor chip 7 is lowered onto the joining material 6 so that the joining material 6 completely wets the mounting surface of the semiconductor chip 7 in addition to the contact surface of the pedestal 4 (FIG. 3).

[0045] Filler particles have been introduced into the joining material 6 at present. The joining material 6, for example, is a silicone. In this execution example, the filler particles are embodied reflective. For example, the filler particles are titanium dioxide particles.

[0046] In a next step, which is schematically shown in FIG. 4, the radiation emitting semiconductor chip 7 is lowered onto the pedestal 4 in such a way that a joining layer 12 of joining material 6 is formed between the contact surface of the pedestal 4 and the mounting surface of the semiconductor chip 7. Furthermore, the joining material 6 partially fills a recess 13, which is limited by the part of the mounting surface projecting over the contact surface. The recess 13 is further delimited by the side surfaces of the pedestal 4 and parts of the surface of the carrier 1, which are protruded by the semiconductor chip 7. At present, only the recess 13 is partially filled with the joining material 6, while the rest of the surface, which is not protruded by the semiconductor chip 7, remains free of the joining material 6. The side surfaces of the semiconductor chip 7 are also advantageously free of the joining material 6. Then the joining material 6 is cured so that a mechanically stable joining layer 12, which establishes a material-locking connection between the support surface of the pedestal 4 and the mounting surface of the semiconductor chip 7, is obtained. Furthermore, during curing a mechanically stable, reflective underfill of the semiconductor chip 7 is created from the cured joining material in the recess 13 (FIG. 5).

[0047] In a next step, which is schematically shown in FIG. 6, the semiconductor chip 7 is electrically contacted, in which two electrical contacts 11 of the semiconductor chip 7, which are arranged on a front side of the semiconductor chip 7, are electrically conductively connected to electrical connection points of the lead frame 2 by a bonding wire 14 (FIG. 6). The front side of the semiconductor chip 7 is opposite the mounting surface of the semiconductor chip 7.

[0048] Then the recess 13 of the housing body 3 is filled with a casting 15, in which phosphor particles are introduced. The phosphor particles are configured to convert blue light of the semiconductor chip 7 into yellow light.

[0049] In the method described in this example, the phosphor particles sediment in the casting 15 and form a wavelength converting layer 16 on the surface of carrier 1 and on the surface of the semiconductor chip 7. The casting 15 is then cured (FIG. 7).

[0050] In the method described in FIGS. 8 to 11, a carrier 1 is again provided first, as already described in connection with FIG. 1 (FIG. 8).

[0051] Then the method steps are carried out as already described in connection with FIGS. 2 to 4, wherein the filler particles in the joining material 6 are not embodied reflective but wavelength converting. The filler particles are configured to convert blue light of the active zone into red light.

[0052] The semiconductor chip 7 is fixed mechanically stable on the contact surface of the pedestal 4 by a joining layer 12, in which wavelength converting filler particles are introduced. Furthermore, the recess 13, which is limited by the part of the mounting surface of the semiconductor chip 7 projecting over the contact surface, the side surfaces of the pedestal 4 and the surface of the carrier 1 below the semiconductor chip 7, is filled with the joining material 6, which has wavelength converting filler particles (FIG. 9). A wavelength converting underfill is thus arranged below the semiconductor chip 7.

[0053] In the next step, the semiconductor chip 7 is again electrically contacted, as already described in connection with FIG. 6 (FIG. 10).

[0054] Then a wavelength converting casting 15 is again introduced into the cavity 5 of the housing body 3, which contains phosphor particles. In contrast to the execution example according to FIGS. 1 to 7, the phosphor particles are configured to convert blue light from the active zone into green light. The phosphor particles sediment in a wavelength converting layer 16 on the surface of the semiconductor chip 7. After sedimentation of the phosphor particles, the casting 15 is cured (FIG. 11).

[0055] FIG. 12 shows a section of an optoelectronic component as it can be manufactured using the method according to FIGS. 1 to 7.

[0056] The optoelectronic component according to the execution example of FIG. 12 has a carrier 1 with a pedestal 4. A semiconductor chip 7 is mounted on the support surface of the pedestal 4 with its mounting surface. The mounting surface protrudes laterally beyond the pedestal 4 and forms a recess 13 with the side surfaces of the pedestal 4 and the surface of the carrier 1, which is protruded by the semiconductor chip 7. The recess 13 is filled with an underfill of a cured joining material 6, into which reflective filler particles, such as titanium dioxide particles, are introduced. The semiconductor chip 7 is mechanically stably connected to the pedestal 4 via the joining layer 12, which is formed from cured joining material 6. The semiconductor chip 7 is electrically contacted at the front via two electrical contacts bonding wires 14.

[0057] Furthermore, the semiconductor chip 7 is surrounded by a wavelength converting layer 16, which is configured to convert blue light of the semiconductor chip 7 into yellow light. The component according to the execution example of FIG. 12 emits mixed colored light composed of unconverted blue light from the semiconductor chip 7 and yellow converted light from the wavelength converting layer 16 to white light.

[0058] FIG. 13 shows a section of an optoelectronic component as it can be manufactured using the method according to FIGS. 8 to 11.

[0059] In the case of the optoelectronic component according to the execution example of FIG. 13, the cured joining material 6 of the underfill is not filled with reflective filler particles, but with wavelength converting filler particles. The wavelength converting filler particles are configured to convert blue light of the semiconductor chip 7 into red light. Furthermore, the wavelength converting layer 16 of the component according to the execution example of FIG. 13 is provided with phosphor particles that convert blue light into green light. The component according to the execution example of FIG. 13 emits mixed colored light consisting of blue light from the semiconductor chip 7, red light from the wavelength converting filler particles and green light from the wavelength converting layer 16.

[0060] The present application claims the priority of the German application DE 102017115656.9, the disclosure content of which is hereby incorporated by reference.

[0061] The invention is not limited by the description on the basis of the execution examples to these. Rather, the invention includes each new feature as well as each combination of features, which in particular includes each combination of features in the patent claims, even if that feature or combination itself is not explicitly stated in the patent claims or execution examples.