Optoelectronic semiconductor chip and corresponding production method

Abstract

The optoelectronic semiconductor chip comprises: a front-side radiation-transmissive chip substrate; a back-side semiconductor layer sequence arranged on the chip substrate, the semiconductor layer sequence being configured for radiation emission or radiation detection; and a rear contact element for contacting the semiconductor layer sequence. The chip substrate is integrally formed in a lens shape deviating from the cubic shape. The invention further relates to a method for producing at least one optoelectronic semiconductor chip.

Description

[0001] Description

[0002] The invention relates to an optoelectronic semiconductor chip. The invention also relates to a method for producing at least one optoelectronic semiconductor chip.

[0003] This patent application claims priority to German patent application 10 2023 113 781.6, the disclosure of which is hereby incorporated by reference.

[0004] A light emitting diode (LED) chip can be implemented in the form of a so-called sapphire flip chip. Such an optoelectronic semiconductor chip can comprise a front side radiation-transmissive chip substrate made of sapphire, a back side radiation-emitting semiconductor layer sequence arranged on the chip substrate, and back side contact elements for contacting the semiconductor layer sequence. The semiconductor chip and its chip substrate can generally comprise a cuboid shape. The semiconductor layer sequence can be configured to emit ultraviolet radiation (UV radiation), for example short-wave UV radiation (UV-C radiation).

[0005] During operation, the optical radiation generated by the semiconductor layer sequence can be coupled into the chip substrate and emitted by the chip substrate into the air. The cuboid shape and the high refractive index of the sapphire can lead to a trapping of the optical radiation in the chip substrate, since light rays outside the extraction cone can only be reflected into similar angles outside the extraction cone. With regard to semiconductor layer sequences configured to emit UV-C radiation, the light generation efficiency can be low, so that photon absorption and re-emission in directions within the extraction cone can not be a reasonable way to solve the light extraction problem.

[0006] Other methods that can be used with sapphire flip chips configured to emit blue light radiation can be rather unsuitable. For example, a silicone encapsulant for improving the light extraction efficiency can undergo photothermal degradation when exposed to UV-C radiation. The application of an optical glass lens to improve the efficiency, wherein the lens is joined to the sapphire body by a silicone adhesive, can entail similar photothermal aging risks. On the other hand, a joining without adhesive can require high surface planarity and smoothness on the chip substrate and the lens. From a manufacturing point of view, neither the geometrical nor the surface chemical requirements are easy and most importantly reliably obtainable. Furthermore, the refractive indices of the glass lens and the sapphire body do not match, so that a considerable amount of light can still be trapped in the sapphire body.

[0007] It is an object of the present invention to explicitly point out a solution for an improved optoelectronic semiconductor chip.

[0008] This object is achieved by the features of the independent claims. Further advantageous embodiments of the invention are explicitly pointed out in the dependent claims.

[0009] According to an aspect of the present application, an optoelectronic semiconductor chip is presented. The optoelectronic semiconductor chip comprises a front side radiation transmissive chip substrate, a back side semiconductor layer sequence arranged on the chip substrate, the semiconductor layer sequence being configured for radiation emission or radiation detection, and a back side contact element for contacting the semiconductor layer sequence. The chip substrate is integrally formed in a lens shape deviating from a cuboid shape.

[0010] The presented optoelectronic semiconductor chip can feature a high efficiency and, in case the semiconductor layer sequence is configured for generating optical radiation, a high optical emission and extraction efficiency. In this regard, in an illumination operation of the optoelectronic semiconductor chip or of the semiconductor layer sequence thereof, which can be supplied with electrical energy via the back side contact element, the optical radiation generated by the semiconductor layer sequence can be coupled into the chip substrate and emitted from the chip substrate with a high efficiency. This is possible by integrally forming the chip substrate in an optical lens shape instead of a cuboid shape. In this way, the chip substrate can avoid a continuous reflection of a rectangular cross section of the equivalent angle at the interface between the chip substrate and the external environment or air. Moreover, for at least a portion of the optical radiation generated by the semiconductor layer sequence, which is coupled into the chip substrate and propagates to the aforementioned interface, a perpendicular or substantially perpendicular incidence can be provided, such that any back reflection can be limited to a Fresnel reflection. This can apply to the optical radiation emitted from a central region of a light emission plane provided by the semiconductor layer sequence.

[0011] In a similar way, in case the semiconductor layer sequence is configured for detecting optical radiation, a high detection efficiency can be provided. In this regard, in a detection operation of the optoelectronic semiconductor chip, optical radiation from the external environment can be injected and coupled into the chip substrate and reach the semiconductor layer sequence via the chip substrate, and thus electrical energy generated by the semiconductor layer sequence can be acquired via the back side contact element. The chip substrate comprising the optical lens shape instead of being formed in a cuboid shape makes it possible to reduce back reflections at the interface between the chip substrate and the external environment or air and thus provides an efficient coupling of the optical radiation into the chip substrate.

[0012] In the proposed optoelectronic semiconductor chip, due to the lens shape, the chip substrate can thus constitute an integrated optical lens or a monolithic optical device or a master optical device of the optoelectronic semiconductor chip. By this configuration, the application of an additional and expensive optical lens can be eliminated, allowing the provision of the optoelectronic semiconductor chip in a cost-effective manner. Furthermore, the aforementioned problems, such as the light capture behavior encountered in the case of an adhesive-free attachment of the lens to the cubic chip substrate, or the photo-thermal aging in the case of an adhesive-based attachment of the lens to the chip substrate, can be avoided. In addition, the omission of the additional lens makes it possible to provide an optoelectronic semiconductor chip with a small (smaller) overall height.

[0013] In the following, further possible details and embodiments can be described which can be considered for the optoelectronic semiconductor chip. It should be noted that features described with respect to one embodiment can also apply to other embodiments.

[0014] The semiconductor layer sequence of the optoelectronic semiconductor chip can be configured to generate optical radiation, so that the optoelectronic semiconductor chip can be a light-emitting semiconductor chip or a light-emitting diode (LED) chip. In the illumination operation, the optical radiation can be emitted completely or substantially via the chip substrate into a volume surrounding the chip substrate. Thus, the optoelectronic semiconductor chip can also be referred to as a bulk-emitting semiconductor chip, a bulk emitter or a bulk-emitting flip chip due to the backside contact element.

[0015] The radiation-transmissive chip substrate of the optoelectronic semiconductor chip is integrally made in the lens shape. In this configuration, the chip substrate is not composed of several components which are manufactured separately and connected directly to each other or indirectly via a connecting agent, such as an adhesive. Instead, the chip substrate is integrally made of a radiation-transmissive material. The radiation transmissivity of the chip substrate can at least relate to the wavelength or wavelength range of the optical radiation which the optoelectronic semiconductor chip can emit or detect during operation.

[0016] The chip substrate can be monocrystalline. Furthermore, the optoelectronic semiconductor chip can be formed such that the chip substrate and the semiconductor layer sequence are congruent in a crystallographic preferred direction.

[0017] In a possible embodiment, the chip substrate is made of sapphire.

[0018] In a further possible embodiment, the semiconductor layer sequence is configured to produce ultraviolet radiation, such as UV-C radiation. In this way, the optoelectronic semiconductor chip can be a UV-C radiation-emitting chip or a UV-C LED chip, via which UV light sources in industry can be implemented, and here, for example, for UV disinfection of air, water and / or surfaces. Another application is horticultural lighting.

[0019] The semiconductor layer sequence can also be configured to detect optical radiation such as ultraviolet radiation. In this way, via the optoelectronic semiconductor chip, a detector such as a solar blind UV detector can be implemented.

[0020] With regard to emitting or detecting ultraviolet radiation, the semiconductor layer sequence or its active layer can be based on AlGaInN.

[0021] In addition thereto, other optical radiations and materials for the chip substrate and the semiconductor layer sequence can be considered. As an example, the chip substrate can also be made of silicon carbide, gadolinium gallium garnet, quartz or a semiconductor material such as gallium arsenide. The semiconductor layer sequence can also be configured to generate blue, green, red or infrared optical radiation, which can be implemented with appropriate semiconductor material systems.

[0022] The semiconductor layer sequence can directly adjoin the chip substrate. In this regard, the semiconductor layer sequence can be a layer sequence grown or epitaxially grown on the chip substrate. To this end, the production of the semiconductor layer sequence can comprise forming the semiconductor layer sequence on the chip substrate or a corresponding initial substrate or precursor substrate by performing an epitaxial growth process or a larger initial semiconductor layer sequence provided for a plurality of optoelectronic semiconductor chips manufactured together, from which the chip substrate can subsequently be produced from the corresponding initial substrate or precursor substrate.

[0023] The chip substrate can comprise a planar side facing the semiconductor layer sequence on which the semiconductor layer sequence can be arranged.

[0024] The optical lens shape of the chip substrate can be present at least in partial regions or can be implemented at least by partial segments or lens-like segments of the chip substrate. The lens shape can be formed by the chip substrate comprising a curved shape or a shape approximating a curved shape at least in partial regions. Such a shape can be present in a direction or side facing away from the semiconductor layer sequence. With regard to the approximating curved shape, the approximation can be implemented by adjoining partial surfaces, wherein the partial surfaces can be planar and / or curved. Thus, the lens shape can be implemented such that in all perpendicular cross sections there can be a curved portion or an approximated curved portion at the interface between the chip substrate and the external environment or air. Herein, there can be a smoothly curved boundary line as well as a boundary line approximated by a series of linear portions. Possible configurations for implementing the lens shape of the chip substrate are described in the following.

[0025] In a further embodiment, the chip substrate comprises a partial ellipsoid or a partial sphere shape at least in a partial region, which can comprise a half-ellipsoid or a half-sphere shape. Such a configuration allows for a high light extraction or light detection efficiency of the optoelectronic semiconductor chip. The partial ellipsoid, the partial sphere, the half-ellipsoid or the half-sphere shape can be present at a side facing away from the semiconductor layer sequence. With respect to such a shape, a rotational symmetry can be present with respect to an axis or longitudinal axis perpendicular to a side of the chip substrate on which the semiconductor layer sequence can be positioned. Alternatively, with respect to the partial ellipsoid or the half-ellipsoid shape, different lengths of transversal semi-axes can be present instead of a rotational symmetry.

[0026] In a further embodiment, the chip substrate comprises a Fresnel lens structure at least in a partial region. With such a configuration, a small overall height of the optoelectronic semiconductor chip can be facilitated. The Fresnel lens structure can comprise a centrally curved (e.g. partially spherically curved) partial surface surrounded by a set of step-like annular partial surfaces curved in a vertical cross-section. The Fresnel lens structure can be present at a side facing away from the semiconductor layer sequence.

[0027] In a further embodiment, the chip substrate comprises a facet lens structure at least in a partial region. The facet lens structure can comprise a set of adjoining planar partial surfaces. Via the planar partial surfaces, a partial ellipsoid or a partial sphere shape, e.g. a half-ellipsoid or a half-sphere shape, can be approximated. The facet lens structure can be present at a side facing away from the semiconductor layer sequence.

[0028] In a further embodiment, the chip substrate comprises a dome shape formed by a plurality of adjoining curved partial surfaces at least in a partial region. The curved partial surfaces can be triangular and can converge to a vertex. The dome shape can be formed by four adjoining curved partial surfaces and can thus correspond to the shape of a cloistered vault. The dome shape can be present at a side facing away from the semiconductor layer sequence.

[0029] In a further embodiment, the chip substrate comprises a transition from a polygonal contour to an elliptical or circular contour in a direction away from the semiconductor layer sequence. Such a configuration can be applied if the semiconductor layer sequence further comprises a polygonal contour, which can refer to a plan view of the optoelectronic semiconductor chip. The polygonal contour of the chip substrate and the semiconductor layer sequence can be, for example, a rectangular or a square contour. In such a configuration, the chip substrate can transition from a polygonal base region or footprint to a lens-like section. The lens-like section can comprise a partial ellipsoid or a partial sphere shape, e.g. a half-ellipsoid or a half-sphere shape, or approximate the shape of one of the foregoing, or a Fresnel lens structure. The base region can be a side on which the semiconductor layer sequence is arranged on the chip substrate.

[0030] In a further embodiment, which can also be applied if the semiconductor layer sequence comprises a polygonal, e.g. rectangular or square, contour, the chip substrate comprises a base section on which the semiconductor layer sequence is arranged. The base section comprises a polygonal, e.g. rectangular or square, contour at least in the region of the semiconductor layer sequence. If a plurality of optoelectronic semiconductor chips are produced together and then separated, this configuration can prove advantageous from a manufacturing point of view. The base section can be prismatic or cuboidal, so that the polygonal contour can also be present at a distance from the semiconductor layer sequence. Furthermore, in the direction away from the semiconductor layer sequence, the chip substrate can transition from the prismatic or cuboidal base section to a lenticular section. The lenticular section can comprise a partial ellipsoid or partial sphere shape, e.g. a half-ellipsoid or half-sphere shape, or a shape approximating one of the aforementioned, or a Fresnel lens structure. Alternatively, instead of a transition, the chip substrate can comprise a lenticular section adjoining the base section. The lenticular section can be configured as described above.

[0031] As described above, the lenticular shape of the chip substrate can be realized by the chip substrate comprising a curved shape at least in a partial region. In this case, complex configurations can also be considered in which curvatures with different directions of curvature can be present and thus convexly curved and concavely curved partial surfaces can be present. An example is a toroidal lenticular shape, which can be formed by a substantially convexly curved lenticular body or section having a shape similar to that of a partial ellipsoid or partial sphere and comprising a concavely curved recess in a central region. Furthermore, in these configurations, the aforementioned features can be provided in relation to the chip substrate, e.g. a transition from a polygonal contour to an elliptical or circular contour in the direction away from the semiconductor layer sequence and / or the presence of a base section on which the semiconductor layer sequence is arranged.

[0032] In a further embodiment, the optoelectronic semiconductor chip further comprises a reflective layer arranged on the chip substrate. The reflective layer can be arranged circumferentially on the chip substrate and can extend to the side on which the semiconductor layer sequence can be located on the chip substrate. The reflective layer can further be arranged on a base section of the chip substrate and can be present circumferentially or on lateral side walls of the base section. The base section can be configured as described above and thus can be prismatic or cuboidal. The reflective layer can comprise a metallic material or a combination of a metallic material and a dielectric material. Via the reflective layer, which can also be referred to as a mirror layer, lateral radiation emission in the region close to the semiconductor layer sequence or in the region of the base section of the chip substrate can be suppressed.

[0033] In a further embodiment, the optoelectronic semiconductor chip further comprises an anti-reflection layer arranged on the chip substrate. The anti-reflection layer can comprise a dielectric material or a plurality of dielectric materials. With reference to the latter, the anti-reflection layer can be configured as a multi-layer stack. Via the anti-reflection layer, Fresnel reflections can be suppressed, such that a high efficiency (light extraction efficiency or detection efficiency) of the optoelectronic semiconductor chip can be facilitated.

[0034] As described above, the semiconductor layer sequence can comprise a polygonal contour when seen in a plan view of the optoelectronic semiconductor chip. Alternatively, an elliptical or circular contour can be provided when seen from above. This can be considered, for example, when the chip substrate further comprises an elliptical or circular contour at the side of the chip substrate on which the semiconductor layer sequence can be arranged.

[0035] The optoelectronic semiconductor chip can further be configured such that the chip substrate at least partially laterally protrudes from the semiconductor layer sequence at the side of the chip substrate on which the semiconductor layer sequence can be arranged. The lateral protrusion of the chip substrate from the semiconductor layer sequence at the respective side of the chip substrate can also be present at the entire lateral circumference of the semiconductor layer sequence. Such a configuration can facilitate a high efficiency of the optoelectronic semiconductor chip.

[0036] According to a further aspect of the present application, a method for producing at least one optoelectronic semiconductor chip is presented. The optoelectronic semiconductor chip comprises a front-side radiation-transmissive chip substrate, a rear-side semiconductor layer sequence arranged on the chip substrate, the semiconductor layer sequence being configured for radiation emission or radiation detection, and a rear-side contact element for contacting the semiconductor layer sequence. In the method, the chip substrate is integrally formed in a lens shape deviating from a cubic shape.

[0037] The optoelectronic semiconductor chip produced by the method can have a high efficiency due to the fact that the chip substrate is integrally produced in a lens shape instead of being formed in a cubic shape. If the semiconductor layer sequence is configured for producing optical radiation, a high light emission and extraction efficiency can be achieved by the lens shape of the chip substrate. If the semiconductor layer sequence is configured for detecting optical radiation, the lens shape of the chip substrate can provide a high detection efficiency.

[0038] The method can be used for producing the above-described optoelectronic semiconductor chip or one or more embodiments of the above-described optoelectronic semiconductor chip. In a corresponding manner, the aspects and details described above with reference to the optoelectronic semiconductor chip can also be used for the production method. For example, the semiconductor layer sequence can directly adjoin the chip substrate.

[0039] In the following, possible details and embodiments that can be considered for the production method are described. It should be noted that features described with respect to one embodiment can also be applicable to other embodiments.

[0040] In this method, the semiconductor layer sequence can be generated by one of the following:

[0041] growing a semiconductor layer sequence on a chip substrate; or

[0042] growing a larger initial semiconductor layer sequence on a radiation-transmissive initial substrate, which is provided for a plurality of optoelectronic semiconductor chips manufactured together, and subsequently structuring the initial semiconductor layer sequence into a plurality of semiconductor layer sequences arranged next to each other on the initial substrate, the plurality of semiconductor layer sequences being provided for the plurality of optoelectronic semiconductor chips, and the chip substrate being subsequently or later generated from the initial substrate.

[0043] In a further embodiment, the chip substrate is first provided with a lens shape, and subsequently the semiconductor layer sequence and the contact element arranged on the chip substrate are formed. Providing the chip substrate with the lens shape can comprise providing an initial chip substrate which does not yet have the lens shape, and afterwards processing the chip substrate so that the chip substrate then comprises the lens shape. The initial substrate can comprise a cuboid shape. The processing of the chip substrate can be performed mechanically using a suitably designed tool. Forming the semiconductor layer sequence can comprise growing or epitaxially growing the semiconductor layer sequence on the chip substrate. Thereafter, the contact element via which the semiconductor layer sequence can be contacted can be generated by a suitable processing.

[0044] With reference to the aforementioned variants of the method, a plurality of optoelectronic semiconductor chips can be manufactured together by providing a plurality of chip substrates with a lens shape and subsequently forming or growing a semiconductor layer sequence on each chip substrate and forming a contact element with respect to each semiconductor layer sequence. For these processes, the plurality of chip substrates can be assembled on a common carrier for efficient processing.

[0045] In a further embodiment, the optoelectronic semiconductor chip is first provided so that the chip substrate comprises an initial shape which does not comprise a lens shape, and subsequently the lens shape is formed by processing the chip substrate. The initial shape can be a cuboid shape. The processing of the chip substrate can be performed mechanically using a suitably designed tool.

[0046] With reference to the preceding embodiments, it can be provided that, after the processing of the initial substrate for forming the lens shapes, singulation is performed to provide a plurality of optoelectronic semiconductor chips which are then separated from one another. In this process, the processed initial substrate comprising the lens shapes can constitute an assembly of a plurality of connected chip substrates each having a respective lens shape. By the subsequent singulation, the chip substrates can be separated from one another and thus a plurality of independent optoelectronic semiconductor chips can be provided. The singulation can comprise sawing or laser scribing and subsequent breaking.

[0047] In a further embodiment where a plurality of optoelectronic semiconductor chips is produced together, a radiation-transmissive initial substrate is provided on which a plurality of semiconductor layer sequences arranged next to one another are arranged which are provided with contact elements for a plurality of optoelectronic semiconductor chips, and subsequently a lens shape for the plurality of optoelectronic semiconductor chips is formed by processing the initial substrate. The plurality of semiconductor layer sequences arranged on the initial substrate can be formed by growing or epitaxially growing a larger initial semiconductor layer sequence on the initial substrate and subsequently structuring this semiconductor layer sequence into a plurality of individual semiconductor layer sequences. The contact elements can be produced before or after the structuring of the semiconductor layer sequences.

[0048] With reference to the preceding embodiments, it can be provided that, after the processing of the initial substrate for forming the lens shapes, singulation is performed to provide a plurality of optoelectronic semiconductor chips which are then separated from one another. In this process, the processed initial substrate comprising the lens shapes can constitute an assembly of a plurality of connected chip substrates each having a respective lens shape. By the subsequent singulation, the chip substrates can be separated from one another and thus a plurality of independent optoelectronic semiconductor chips can be provided. The singulation can comprise sawing or laser scribing and subsequent breaking.

[0049] Alternatively, the processing of the initial substrate for providing the lens shapes can be performed such that the processing of the initial substrate is accompanied by the singulation for providing a plurality of optoelectronic semiconductor chips which are then separated from one another. In this variant of the method, the processing of the initial substrate is not only performed for providing the lens shapes but also for providing a plurality of independent optoelectronic semiconductor chips.

[0050] In a further embodiment, the processing of the initial substrate for providing the lens shapes and, if applicable, for performing the singulation, is performed mechanically. For this purpose, a suitably designed tool can be applied.

[0051] In an alternative embodiment, the processing of the initial substrate for providing the lens shape and (if applicable) monolithization is performed by etching. Etching can be performed in a single etching step using a suitable etch or photoresist mask. Alternatively, several successive etching steps can be performed using a suitable etch or photoresist mask. Etching can be dry etching or wet chemical etching.

[0052] In cases where the initial substrate is etched so that it is not monolithized and therefore additional monolithization is performed as indicated above, protection of the semiconductor layer can be achieved during the etching process.

[0053] In another embodiment, the initial substrate is locally modified by irradiation with laser radiation prior to etching to predetermine the lens shape. In this way, the lens shape to be produced by subsequent etching can be pre-defined with high reliability and accuracy. Furthermore, the photolithography mask step can be omitted, and processing time can be reduced. The local modification can be local amorphization, i.e., the irradiated substrate material of the initial substrate changes from a crystalline state to an amorphous state, and can have the effect of the irradiated substrate material including higher etchability. In this way, etching can occur selectively, only or substantially only in the modified region of the initial substrate. Etching can be wet chemical etching or vapor phase etching. The applied laser radiation can be ultraviolet laser radiation.

[0054] Through the selective laser-induced etching described above, a lens shape, such as a Fresnel lens structure, can be formed in the initial substrate. Additionally, trenches can be created in the initial substrate along with the lens shape, and these trenches can be applied to facilitate subsequent monolithization.

[0055] In another embodiment, a trench is formed on one side of the initial substrate on which a sequence of semiconductor layers is disposed, and a reflective layer is subsequently formed at least on the sidewalls of the trench. The trenches can be formed in the form of a continuous trench structure and can exist between and around the semiconductor layer sequences. The trenches can be formed by etching, for example, laser-induced etching as described above. Using this variation of the method, and by performing subsequent monolithization, multiple optoelectronic semiconductor chips can be provided, each semiconductor chip including a chip substrate on which a reflective layer can be circumferentially disposed.

[0056] In the production method, additional processing steps may be performed. As an example, the method may also include forming an anti-reflective layer. This step can be performed after the aforementioned processing of the initial substrate used to form the lens shape and before monolithization. Here, the anti-reflective layer can be formed on the processed initial substrate including the lens shape. This process can simplify the formation of the anti-reflective layer.

[0057] The advantageous configurations and modifications of the invention described above and / or set forth in the dependent claims—except, for example, in cases of explicit dependency or incompatible alternatives—can be used individually or in any desired combination of them.

[0058] The above-described properties, features, and advantages of the present invention, as well as the ways in which they are realized, will become clearer and more apparent in conjunction with the following description of exemplary embodiments illustrated in conjunction with the schematic diagrams, wherein:

[0059] Figure 1 An optoelectronic semiconductor chip is shown, comprising a front-side chip substrate, a rear-side semiconductor layer sequence, and rear-side contact elements, wherein the chip substrate has a semi-ellipsoidal shape;

[0060] Figure 2 The lighting operation is shown Figure 1 Optoelectronic semiconductor chips;

[0061] Figure 3 Different outlines of the chip substrate and semiconductor layer sequence are shown;

[0062] Figure 4 An optoelectronic semiconductor chip including a chip substrate having a hemispherical shape is shown;

[0063] Figure 5 and Figure 6 An optoelectronic semiconductor chip including a chip substrate having a semi-ellipsoidal shape is shown;

[0064] Figure 7 An optoelectronic semiconductor chip including a chip substrate with a faceted lens structure is shown;

[0065] Figure 8 An optoelectronic semiconductor chip including a chip substrate with a Fresnel lens structure is shown;

[0066] Figure 9 This illustrates an optoelectronic semiconductor chip including an anti-reflective layer disposed on a chip substrate;

[0067] Figure 10 An optoelectronic semiconductor chip including a chip substrate having a base section and a section with a semi-ellipsoidal shape is shown;

[0068] Figure 11 An optoelectronic semiconductor chip including a chip substrate having a base section and a section with a Fresnel lens structure is shown;

[0069] Figure 12 An optoelectronic semiconductor chip including a chip substrate having a base section and a section with a semi-ellipsoidal shape is shown;

[0070] Figure 13 Different outlines of the chip substrate and semiconductor layer sequence are shown;

[0071] Figure 14 An optoelectronic semiconductor chip including a chip substrate having a square back side and a section with a semi-ellipsoidal shape is shown;

[0072] Figures 15 to 17 The fabrication of an optoelectronic semiconductor chip is illustrated, including providing a chip substrate and forming a sequence of semiconductor layers and contact elements;

[0073] Figures 18 to 22 The generation of an optoelectronic semiconductor chip is illustrated, including providing multiple optoelectronic semiconductor chips with a cubic chip substrate and mechanically processing the chip substrate;

[0074] Figure 23 and Figure 24 The generation of an optoelectronic semiconductor chip is illustrated, including forming a sequence of semiconductor layers with contact elements on an initial substrate and mechanically processing the initial substrate;

[0075] Figure 25 and Figure 26 It shows Figure 23 and Figure 24 A variation of the method of generating [the substrate], wherein monolithization is performed after processing the initial substrate;

[0076] Figure 27 A chip substrate with a dome shape is shown;

[0077] Figures 28 to 31 The generation of an optoelectronic semiconductor chip is illustrated, including forming a sequence of semiconductor layers with contact elements on an initial substrate and processing the initial substrate by etching using a photoresist mask;

[0078] Figures 32 to 36 The generation of an optoelectronic semiconductor chip is illustrated, including forming a sequence of semiconductor layers with contact elements on an initial substrate and processing the initial substrate by laser-induced etching;

[0079] Figure 37 and Figure 38 The generation of an optoelectronic semiconductor chip including a chip substrate with a Fresnel lens structure is shown;

[0080] Figures 39 to 42 The fabrication of a photoelectric semiconductor chip, including a reflective layer arranged circumferentially on a chip substrate, is illustrated; and

[0081] Figure 43 An optoelectronic semiconductor chip including a chip substrate having a ring lens shape is shown.

[0082] The following schematic diagram illustrates a possible configuration of an optoelectronic semiconductor chip 100 and a corresponding manufacturing method. The optoelectronic semiconductor chip 100 includes a radiation-transmitting chip substrate 110 having a lens shape, which thus forms an integrated or monolithic optical device of the optoelectronic semiconductor chip 100. In this way, the optoelectronic semiconductor chip 100 can be characterized by high efficiency. It should be noted that the schematic diagram may not be to scale. Therefore, the components, elements, and structures shown in the figures may be shown in exaggerated or reduced dimensions to provide a better understanding.

[0083] Figure 1 The photoelectric semiconductor chip 100 is shown in a possible configuration. The photoelectric semiconductor chip 100 is shown in a transverse or vertical cross-sectional view. Figure 1 The left side of the image is shown, and it is represented by horizontal cross-sectional views of two different locations on the chip 100. Figure 1 (See right side) The optoelectronic semiconductor chip 100 can be configured to emit light radiation 210 (see right side). Figure 2 And therefore it can be a light-emitting chip or a light-emitting diode (LED) chip. Therefore, the term "LED chip 100" is also used below.

[0084] Figure 1 The LED chip 100 depicted includes a front-side radiation-transmitting chip substrate 110, a rear-side semiconductor layer sequence 150 disposed on the chip substrate 110, and two rear-side metal contact elements 160 connected to the semiconductor layer sequence 150. Electrical energy can be supplied to the semiconductor layer sequence 150 via the contact elements 160, enabling the semiconductor layer sequence 150 to generate light radiation 210 (see [link to image]). Figure 2 Light generation can be achieved through an active region of the semiconductor layer sequence 150, which can be implemented in the form of a pn junction, a quantum well, or a multi-quantum well structure (not depicted). The generated light radiation 210 can be ultraviolet radiation, such as short-wavelength UV-C radiation, making the LED chip 100 a UV-C LED chip. In this way, the LED chip 100 can be used, for example, for UV disinfection of air, water, and / or surfaces, or for use in garden lighting. For this purpose, the semiconductor layer sequence 150 can be based on AlGaInN.

[0085] The front-side chip substrate 110 of the LED chip 100 is integrally formed of a radiation-transmitting material. The chip substrate 110 may be a single crystal. The chip substrate 110 and the semiconductor layer sequence 150 may correspond in a crystallographically preferred direction. The material used for the chip substrate 110 may be sapphire. In this way, the chip substrate 110 may include high transmittance relative to the light radiation 210 generated by the semiconductor layer sequence 150. In this configuration, and due to the rear-side semiconductor layer sequence 150 and the rear-side contact element 160, the LED chip 100 may also be referred to as a sapphire flip chip.

[0086] The chip substrate 110 includes a planar side 111, hereinafter also referred to as a rear side 111, on which the semiconductor layer sequence 150 is disposed directly. Thus, the semiconductor layer sequence 150 is directly adjacent to the chip substrate 110. In this respect, the semiconductor layer sequence 150 may be a layer sequence epitaxially grown on the chip substrate 110. This may include growing the semiconductor layer sequence 150 or a larger initial semiconductor layer sequence 155 on the chip substrate 110 or on a corresponding initial substrate 115, as explained in more detail below. In addition to the planar rear side 111, the chip substrate 110 also includes a curved side extending from the planar rear side 111, and therefore includes an optical lens shape in the direction away from the semiconductor layer sequence 150. Due to the planar rear side 111, this shape can also be described by expressing "semi-transparent lens". Figure 1 In the configuration depicted, the lens shape is achieved by a semi-ellipsoidal shape 120 or in the form of a semi-ellipsoidal shape 120. In the present case, the chip substrate 110 is more elongated than a hemisphere, so its shape can also be described as a high dome.

[0087] Figure 1 The chip substrate 110 of the LED chip 100, shown and implemented as a semi-ellipsoid, includes rotational symmetry about a longitudinal axis 205 perpendicular to the rear side 111. Therefore, the chip substrate 110 includes a circular profile at and further away from the rear side 111. This is based on the illustration of the LED chip 100 and its chip substrate 110. Figure 1 Two horizontal cross-sectional views become apparent at two different locations—namely, at rear side 111 and at a certain distance from rear side 111. The semiconductor layer sequence 150 can include a square outline in the planar view, as shown in the horizontal cross-sectional view associated with rear side 111.

[0088] exist Figure 1 In the LED chip 100 depicted, the chip substrate 110 protrudes laterally from the semiconductor layer sequence 150 in a region or edge region on the rear side 111, as indicated by the lateral protrusion 207. The protrusion 207 is present throughout the entire lateral periphery of the semiconductor layer sequence 150. Due to the circular outline of the chip substrate 110 at the rear side 111 and the square outline of the semiconductor layer sequence 150, the protrusion 207 has different dimensions along the periphery of the semiconductor layer sequence 150.

[0089] Figure 1The figure also indicates the vertical thickness 200 of the chip substrate 110, the vertical thickness 201 of the semiconductor layer sequence 150 together with the contact element 160, and the lateral width 202 of the LED chip 100 or the chip substrate 110 present on the back side 111. The thickness 200 can be in the single-digit millimeter range or less. The thickness 201 can be in the single-digit or double-digit micrometer range. The lateral width 202 can be in the single-digit millimeter range or less. The protrusion 207 can be in the sub-millimeter range. This numerical information can also be applied to the configuration of the LED chip 100 shown in other figures.

[0090] Figure 2 The illustration shows the lighting operation. Figure 1 The LED chip 100. In this case, the light radiation 210 generated by the semiconductor layer sequence 150 can be coupled to the radiation-transmitting chip substrate 110 and emitted from the radiation-transmitting chip substrate 110 into the volume surrounding the chip substrate 110. In this respect, the LED chip 100 can also be referred to as a volume emitter or a volume-emitting flip chip. Due to the lens shape of the chip substrate 110, the light output from the chip substrate 110 can occur with high efficiency, which can be higher than the efficiency of LED chips including chip substrates with a cubic shape. This is because the lens shape of the chip substrate 110 can avoid replicating a rectangular cross section of the equivalent angle during continuous reflection at the interface between the chip substrate 110 and the external environment or air. In addition, a portion of the light radiation 210 generated by the semiconductor layer sequence 150—that is, substantially from the central region of the semiconductor layer sequence 150—can be incident perpendicularly or substantially perpendicularly at the interface between the chip substrate 110 and the external environment or air, such that back reflection can be limited to Fresnel reflection. The lateral protrusions 207 of the chip substrate 110 can contribute to high efficiency because they also allow a corresponding portion of the light radiation 210 emitted from the edge region of the semiconductor layer sequence 150 to be incident vertically or substantially vertically at the aforementioned interface.

[0091] The following is a description of other possible variations and configurations that may be considered with respect to the LED chip 100 described herein. Corresponding features and details, as well as components with the same or identical functions, are not described in detail below. For details regarding these, refer instead to the description above. Furthermore, aspects and details mentioned with respect to one configuration may also apply to another configuration, and features of two or more configurations may be combined with each other.

[0092] A possible modification to the LED chip 100 is that, when viewed in a plan view of the LED chip 100, the semiconductor layer sequence 150 includes contours other than the square outline. For illustrative purposes, in Figure 3The diagram shows another possible contour as an example, viewed in plan view. As shown, the semiconductor layer sequence 150 may also include a circular contour corresponding to the circular contour of the rear side 111 of the chip substrate 110. Furthermore, for the semiconductor layer sequence 150, polygonal contours other than square contours, such as hexagonal or triangular contours, can be considered. In the case of a circular contour for the semiconductor layer sequence 150, the chip substrate 110 at the rear side 111 protrudes from the lateral protrusion 207 of the semiconductor layer sequence 150 (see...). Figure 1 The periphery of the semiconductor layer sequence 150 can be uniform.

[0093] Figure 4 A further configuration of the LED chip 100 is depicted, including a chip substrate 110 having an optical lens shape in the form of a hemispherical shape 121. In this respect, the vertical thickness of the chip substrate 110 can be greater than... Figure 1 The chip substrate 110 depicted has a small vertical thickness. This shape can also be described as a hemispherical dome.

[0094] The presence of a smaller vertical thickness also applies Figure 5 The LED chip 100 is configured as depicted. Here, the chip substrate 110 has another optical lens shape, and in this case, it takes the form of a flattened semi-ellipsoidal shape 122. This shape can also be referred to as a shallow dome.

[0095] Figure 6 An alternative configuration of the LED chip 100 is shown, including a chip substrate 110 having an optical lens shape in the form of a semi-ellipsoidal shape 123. In this case, with Figure 1 Unlike the rear side 111, the chip substrate 110 does not include rotational symmetry with respect to the longitudinal axis 205 perpendicular to the rear side 111. Therefore, the chip substrate 110 has an elliptical profile, rather than a circular profile, at and further away from the rear side 111. This is based on... Figure 6 The horizontal cross-sectional view shown becomes clear. Here, the semi-ellipsoidal shape 123 is characterized by lateral semi-axis of varying lengths. The semiconductor layer sequence 150 may include a non-square rectangular profile in the planar view, or another profile, such as an elliptical profile, or another polygonal profile, such as a hexagonal profile, as well as... Figure 6 As shown.

[0096] Another possible configuration is to realize the optical lens shape of the chip substrate 110 by means of a shape that approximates a curved shape. This approximation can be achieved through adjacent partial surfaces, wherein the partial surfaces can be planar and / or curved. In this respect, lens shapes including curved surfaces, such as those shown herein and other potential shapes not shown, can be approximated by forming a chip substrate 110 having such adjacent partial surfaces.

[0097] To illustrate, Figure 7 A further configuration of the LED chip 100 is depicted, including a chip substrate 110 having a hemispherical shape, approximated by adjacent planar partial surfaces 134. Thus, this shape represents a faceted lens structure 124. Figure 7 Unlike other faceted lens structures, such a faceted lens structure 124 can also be implemented in the form of an ellipsoid, allowing for structures similar to, for example, those... Figure 1 , Figure 5 and Figure 6 The shapes shown are (not depicted).

[0098] Figure 8 An alternative configuration of the LED chip 100 is shown, including a chip substrate 110 having an optical lens shape, which in this case is implemented in the form of a Fresnel lens structure 125. The Fresnel lens structure 125 includes a central, partially spherically curved partial surface 135 and a set of concentric annular partial surfaces 136 in a stepped manner surrounding the partial surface 135, the partial surfaces 136 being curved in a vertical cross-section. In this configuration, the chip substrate 110, and therefore the LED chip 100, may include a small vertical thickness.

[0099] Another possible configuration is to provide an additional anti-reflective layer 170 on the chip substrate 110 of the LED chip 100. This is Figure 9 The LED chip 100 shown here. Here, the LED chip 100 includes a chip substrate 110 having a hemispherical shape 121 on which an anti-reflective layer 170 is disposed. The anti-reflective layer 170 can be made of a dielectric material. The anti-reflective layer 170 can also be configured as a multilayer stack of different dielectric materials. The anti-reflective layer 170 allows Fresnel reflection to be overcome or suppressed, resulting in improved efficiency of the LED chip 100. For the LED chip 100 shown in other figures here, for example... Figure 1 , Figure 5 , Figure 6 , Figure 7 and Figure 8 Alternatively, as depicted in the figures described below, an additional anti-reflective layer 170 may be applied on the chip substrate 110.

[0100] Figure 10 An additional configuration of the LED chip 100 is shown, including a chip substrate 110 having an optical lens shape, which can represent... Figure 1 Further modifications to the LED chip 100 depicted in the image. Figure 10In the diagram, the LED chip 100 is shown in a vertical cross-sectional view and in horizontal cross-sectional views at five different locations, including a rear side 111 and four additional locations at various distances from the rear side 111. The chip substrate 110 includes a rear cubic base section 130 constituting the rear side 111, on which a radiative emission semiconductor layer sequence 150 is disposed. The semiconductor layer sequence 150 includes a square outline in the plan view. This also applies to the base section 130 of the chip substrate 110, such that the chip substrate 110 includes a square outline at the rear side 111 and at a certain distance from the rear side 111. Extending from the base section 130 in a direction away from the rear side 111, the chip substrate 110 merges into a semi-ellipsoidal shape 120, which exists in the front portion region of the chip substrate 110 and thus constitutes a front lenticular section of the chip substrate 110. In this configuration, there is a transition from a square outline to a circular outline, as shown in the diagram. Figure 10 The horizontal cross-sectional view becomes clear. If multiple LED chips 100 are manufactured together as a common component and then separated, then... Figure 10 The design of the chip substrate 110 shown.

[0101] The layout of the chip substrate 110 with base segment 130 can also be considered with respect to other lens shapes, such as those shown in the other figures here—for example, including hemispherical shape 121 (not depicted). For illustration, Figure 11 An additional configuration of the LED chip 100 is shown, including a chip substrate 110 having an optical lens shape, which can represent... Figure 8 Modifications to the LED chip 100 depicted in the image. Figure 11 In the diagram, the LED chip 100 is shown in a vertical cross-sectional view and in horizontal cross-sectional views at four different locations, including the rear side 111 and three additional locations at various distances from the rear side 111. The radiation-emitting semiconductor layer sequence 150 disposed on the chip substrate 110 and the rear side 111 of the chip substrate 110 have a square outline in the plan view. The chip substrate 110 includes a cubic base segment 130 constituting the rear side 111, which in this case merges in the direction away from the rear side 111 into a front lenticular segment of the chip substrate 110 including a Fresnel lens structure 125. Therefore, there is a transition from a square outline to a circular outline, as shown in the diagram. Figure 11 The horizontal cross-sectional view becomes clear.

[0102] Regarding the chip substrate 110, including the base section 130, a transitionless layout can also be considered. Figure 12 An additional configuration of the LED chip 100 is shown, including a chip substrate 110 having an optical lens shape, which can represent...Figure 1 Another modification to the LED chip 100 depicted in the image. Figure 12 In the diagram, the LED chip 100 is shown in a vertical cross-sectional view and in horizontal cross-sectional views at three different locations, including the rear side 111 and two additional locations at various distances from the rear side 111. The radiative emitting semiconductor layer sequence 150 disposed on the chip substrate 110 and the rear side 111 of the chip substrate 110 have a square outline in the plan view. The chip substrate 110 includes a cubic base segment 130 constituting the rear side 111 and a front lenticular segment directly adjacent to the cubic base segment 130 and including a semi-ellipsoidal shape 120. Such a layout of the chip substrate 110, including the base segment 130 and another front lenticular segment adjacent to the base segment 130 without a transition between them, can also be considered with respect to other lenticular shapes, such as those shown in other figures here—for example, including a hemispherical shape 121 (not depicted).

[0103] Regarding the base section 130 of the chip substrate 110, a prismatic shape with a polygonal outline, different from a cube shape, can be considered in the planar view. Figure 13 The base segment 130 of the chip substrate 110 is shown to have two possible configurations, including a hexagonal profile and a triangular profile. Figure 13 It is also shown that the semiconductor layer sequence 150 disposed on the chip substrate 110 may also include hexagonal or triangular outlines. Corresponding to the configuration described above, the base segment 130 may be fused into or may be directly adjacent to the front lens-shaped segment (not depicted) of the chip substrate 110.

[0104] Figure 14 An additional configuration of the LED chip 100 is shown, including a chip substrate 110 having an optical lens shape, which can represent... Figure 10 Modifications to the LED chip 100 depicted in the image. Figure 14 In the diagram, the LED chip 100 is shown in a vertical cross-sectional view and in horizontal cross-sectional views at four different locations, including the rear side 111 and three additional locations at various distances from the rear side 111. The radiation-emitting semiconductor layer sequence 150 disposed on the chip substrate 110 and the rear side 111 of the chip substrate 110 have a square outline in the plan view. Figure 10 Unlike the previous method, the cubic base segment 130 is absent. Instead, the chip substrate 110 is fused from the square rear side 111 into a semi-ellipsoidal shape 120 in the direction away from the rear side 111, which constitutes a lenticular segment on the front side of the chip substrate 110. Thus, starting from the rear side 111, there is a transition from a square profile to a circular profile.

[0105] Figure 14The modification to the LED chip 100 depicted is to provide a front lens-shaped segment with another shape, such as a hemispherical shape 121 (not depicted). Figure 14 Another modification to the LED chip 100 depicted is providing a different profile for the rear side 111 of the chip substrate 111. As an example, one could consider... Figure 13 The configuration depicted is shown in the image. Another example is a non-square rectangular rear side 111. In such a configuration, the chip substrate 110 can be fused from the rear side 111 into a shape as shown in the image. Figure 6 The non-rotationally symmetric semi-ellipsoidal shape 123 is depicted in the diagram. The semiconductor layer sequence 150 arranged on the rear side 111 may also include a non-square rectangular outline (not depicted) in the plan view.

[0106] Furthermore, regarding, for example Figure 10 and Figure 12 The cubic base section 130 of the chip substrate 110 depicted can be considered as a cubic shape with a rectangular outline that is not square in the plan view. In such a configuration, in addition to the base section 130, the chip substrate 110 may also include a front lenticular section (not depicted) with a non-rotationally symmetric semi-ellipsoidal shape 123.

[0107] The following describes possible variations of the method for producing LED chip 100, wherein LED chip 100 can be configured as described above. In this regard, corresponding features and details, as well as components with the same or identical functions, will not be described in detail below. For details thereon, refer instead to the description above. Furthermore, aspects and details mentioned with respect to one method variation may also apply to another method variation, and features of two or more variations may be combined with each other.

[0108] Figures 15 to 17 A sequence of possible methods for producing LED chip 100 is shown. For example... Figure 15 As shown, a chip substrate 110 comprising an optical lens shape is first provided. In the present case, the chip substrate 110 comprises a hemispherical shape 121. Alternatively, other shapes may be used, such as those shown in the other figures here. The chip substrate 110 may be made of sapphire and therefore may represent a chip-scale sapphire block. The provision of the chip substrate 110 can be performed by providing an initial sapphire body or chip substrate, such as a chip substrate comprising a cubic shape, and then processing the chip substrate such that the depicted chip substrate 110 comprising a lens shape is then provided. The processing can be performed mechanically using appropriately designed tools (not depicted). Subsequently, as Figure 16As depicted, a semiconductor layer sequence 150 is formed on the planar backside 111 of a chip substrate 110 (this can be done by epitaxially growing the semiconductor layer sequence 150 on the chip substrate 110), and the semiconductor layer sequence 150 can be formed via a metal contact element 160 electrically contacting it. The semiconductor layer sequence 150 may be based on AlGaInN and may include an active region (not depicted) configured to generate optical radiation, such as UV-C radiation. Subsequently, as Figure 17 As shown, the semiconductor layer sequence 150 is structured such that the chip substrate 110 protrudes laterally from the semiconductor layer sequence 150 at the rear side 111. This step involves partially removing the semiconductor layer sequence 150, which can be done, for example, by etching.

[0109] If applicable, the structuring of semiconductor layer sequence 150 can be omitted, making Figure 16 The components shown can represent the LED chip 100 to be produced. In this case, the chip substrate 110 at the rear side 111 may not protrude laterally from the semiconductor layer sequence 150. Figure 15 and Figure 16 Alternatively, the formation of contact elements 160 can be performed after the semiconductor layer sequence 150 has been structured.

[0110] The aforementioned generation method can also be performed in a manner that generates multiple LED chips 100 together. This can be achieved by providing multiple chip substrates 110, subsequently forming a semiconductor layer sequence 150 on each chip substrate 110, forming contact elements 160 with respect to each semiconductor layer sequence 150, and structuring the semiconductor layer sequence 150, if applicable. The formation and structuring of the semiconductor layer sequence 150 and the contact elements 160 can be performed together for all LED chips 100. Here, the multiple chip substrates 110 can be assembled on a common carrier for efficient processing (not depicted).

[0111] Figures 18 to 22 Another sequence of methods for producing LED chip 100 is shown. In this method, a larger radiation-transmitting initial substrate 115 is provided, such as... Figure 18 As shown. The initial substrate 115 can be made of sapphire. The initial substrate 115 includes two planar opposing main sides, i.e., sides with the largest surface area, hereinafter referred to as the front side 112 and the rear side 111. Then, as... Figure 19As shown, a larger initial semiconductor layer sequence 155 is formed on the back side 111 of the initial substrate 115, which can be achieved by performing an epitaxial growth process. The initial semiconductor layer sequence 155 may be based on AlGaInN and may include an active region (not depicted) configured to generate optical radiation, such as UV-C radiation. Next are additional steps, such as structuring the initial semiconductor layer sequence 155 into a plurality of individual semiconductor layer sequences 150 arranged adjacent to each other, and forming metal contact elements 160 through which the semiconductor layer sequences 150 can be electrically contacted, such that providing... Figure 20 The arrangement is shown. For each LED chip 100 to be produced, a semiconductor layer sequence 150 and two contact elements 160 are formed. The structuring of the initial semiconductor layer sequence 155—where a portion of the initial semiconductor layer sequence 155 is removed—can be performed by etching, also known as mesa etching. The formation of the contact elements 160 can be performed before or after the structuring of the initial semiconductor layer sequence 155. Subsequently, for Figure 20 The arrangement is monolithically configured to provide multiple LED chips 100, such as Figure 21 As shown. This step is performed by cutting the initial substrate 115 at the corresponding separation line 220. The cutting can be performed by sawing or by laser scribing followed by breaking. The resulting individual LED chip 100 includes a chip substrate 110 derived from the initial substrate 115 and has a cubic shape.

[0112] Next, mechanical processing is performed on the chip substrate 110 of the LED chip 100 to provide an optical lens shape for the chip substrate 110. To illustrate, in Figure 22 The step is illustrated with respect to an LED chip 100. Processing of the chip substrate 110 is performed using a suitably designed tool 230. In the illustrated configuration example, the process is performed by grinding, and the applied tool 230 comprises an inwardly curved hemispherical grinding surface. In this way, by moving the tool 230 toward the front side 112 of the chip substrate 110 and simultaneously rotating the tool 230, a lens shape, in this case a hemispherical shape 121, is provided for the chip substrate 110. In addition... Figure 22 In addition to the process depicted herein, other lens shapes, such as those shown in the other figures, such as a semi-ellipsoidal shape 120, can be provided by machining the chip substrate 110 with appropriately designed tools (not depicted).

[0113] Figure 23 and Figure 24 An additional sequence of methods for producing LED chip 100 is shown. In this case, the process described above is first performed. Figures 18 to 20The process of interpretation is to obtain an initial substrate 115 having a sequence of semiconductor layers 150 arranged adjacent to each other and contact elements 160. Then, as... Figure 23 As shown, the initial substrate 115 is mechanically processed using a suitably designed tool 231. This results in the provision of a separate chip substrate 110 comprising an optical lens shape and, consequently, a separate LED chip 100, such as... Figure 24 As depicted in the diagram. In this regard, the initial substrate 115 is processed to produce the lens shape—forming a corresponding lens shape in the region of each semiconductor layer sequence 150—and to achieve monolithicization. The applied tool 231 takes the form of a sawing wheel or grinding wheel with correspondingly formed edges, and the tool 231 simultaneously rotates and moves—including horizontal movement in directions perpendicular to each other—to... Figure 20 The arrangement depicted forms the LED chip 100. The resulting lens shape of the chip substrate 110 is in the form of a dome shape 127, which will be discussed below. Figure 27 Let's explain in more detail.

[0114] Figure 25 and Figure 26 The modification of the aforementioned method sequence is shown, wherein the execution is performed using tool 231 (see Figure 23 The initial substrate 115 is mechanically processed to produce a lens shape with a dome shape 127, but without monolithization. Therefore, a corresponding dome shape 127 is formed in the region of each semiconductor layer sequence 150. In this way, as... Figure 25 As depicted, the initial substrate 115 after processing constitutes an assembly of multiple interconnected chip substrates 110, each chip substrate 110 having a corresponding dome shape 127. Then, as... Figure 26 As shown, monolithization is performed where the initial substrate 115 is cut at corresponding separation lines 220 in the region between the dome shapes 127, thereby producing individual LED chips 100, each LED chip 100 including a chip substrate 110. Here, in addition to the lenticular segments having the dome shapes 127, the chip substrate 110 also includes a base segment 130 adjacent to the lenticular segments having the dome shapes 127 and comprising a cubic shape. Monolithization can be performed by sawing or by laser scribing followed by breaking.

[0115] Figure 27 A chip substrate 110 comprising a dome shape 127 is depicted, which can be produced by performing a variation of the method described above. The dome shape 127 is formed by four adjacent triangular, curved partial surfaces 137 converging to a apex. This shape corresponds to the shape of a colonnade vault. For performing the above reference... Figure 25 and Figure 26In the case of the explained method sequence, the chip substrate includes an additional base segment 130.

[0116] Forming an optical lens shape can be performed not only by mechanical processing but also by etching. In this way, a chip substrate 110 and a lens shape with a smooth surface condition can be produced. In contrast, the surface condition in the case of mechanical processing may be (somewhat) rough. Possible examples involving etching are described below.

[0117] Figures 28 to 31 Another sequence of methods for producing LED chip 100 is shown. Here, the same procedure is first performed as described above. Figures 18 to 20 The process is explained to obtain an initial substrate 115 with a semiconductor layer sequence 150 and contact elements 160. Subsequently, a structured etch mask including a separate portion of photoresist 240 is provided for the front side 112 of the initial substrate 115. The portion of the photoresist 240 includes curved and, for example, partially spherical or hemispherical shapes, such as... Figure 28 As indicated. This shape of the photoresist 240 can be formed, for example, by heat treatment or by performing grayscale photolithography. Subsequently, etching of the initial substrate 115 is performed using a photoresist mask from the front side 112 toward the rear side 111, resulting in a separate chip substrate 110 including an optical lens shape and thus a separate LED chip 100, as shown. Figures 29 to 31 As shown. In this regard, an etching process is performed on the initial substrate 115 to generate the lens shape—forming a corresponding lens shape in the region of each semiconductor layer sequence 150—and to achieve monolithic fabrication. The etching can be dry etching, the etching effect 245 of which is indicated by the arrow. During etching, not only the material of the initial substrate 115 is removed, but also the material of the photoresist 240 is removed, thereby allowing the lens shape to be formed progressively. The lens shape can be in the form of a semi-ellipsoidal shape 120, making it possible to manufacture, for example, including... Figure 1 The LED chip 100 is shown in the configuration shown.

[0118] The modification to the aforementioned method sequence is that instead of completely etching the initial substrate 115, the substrate 115 is etched to create a lens shape or lens-like segment, for example, a semi-ellipsoidal shape 120, without resulting in monolithization. In this way, the processed initial substrate 115 after etching can include, for example, a lens shape or lens-like segment. Figure 25The configuration shown can thus form an assembly of multiple connected chip substrates 110, each chip substrate 110 having a corresponding lens shape. This process enables the protection of the semiconductor layer sequence 150 during the etching step. To provide the LED chip 100, additional monolithization is performed, wherein the initial substrate 115 (not depicted) is cut, for example, by sawing or by laser scribing and subsequent breaking.

[0119] The aforementioned modification to the etching method involves producing other lens shapes, such as a hemispherical shape 121. Furthermore, instead of performing a single etching process using a shaped photoresist mask, multiple successive etching steps can be performed using a suitable photoresist mask, which is continuously applied to the initial substrate 115 and removed between actual etching steps. Here, the etching can be dry etching or wet chemical etching. In the case of wet chemical etching, an etchant (not depicted) such as a hot alkaline etching solution can be applied.

[0120] Figures 32 to 36 An alternative method sequence for producing LED chip 100 using selective laser-induced etching is shown. This process eliminates the photolithography mask step and reduces processing time. Here, the same procedure described above is first performed. Figures 18 to 20 The explained steps are to obtain an initial substrate 115 with a semiconductor layer sequence 150 and contact elements 160. Subsequently, as... Figure 32 and Figure 33 As shown, an initial substrate 115 is locally irradiated with laser radiation 250 to cause local modification of its substrate material. In this process, the laser radiation 250 is directed to the front side 112 of the initial substrate 115 and can therefore be introduced into the substrate 115 via the front side 112. The resulting local modification can be amorphization, such that previously crystalline regions of the initial substrate 115 are converted into amorphous regions 255, as... Figure 33 As indicated. As described above, the initial substrate 115 may be a sapphire substrate, allowing the formation of localized amorphous sapphire regions 255. Within the amorphous regions 255, the initial substrate 115 exhibits higher etchability compared to the remainder of the substrate 115. Thus, localized laser irradiation, also known as laser damage, is performed, providing a predetermined lens shape within the initial substrate 115 via the amorphous regions 255 formed therein.

[0121] The laser radiation 250 can be ultraviolet laser radiation and can be applied in pulsed form. The laser radiation 250 is generated by a laser device (not depicted) that can be configured as a high-energy-density laser. Furthermore, the initial substrate 115 can be irradiated with the laser radiation 250 in a scanning manner by moving the laser device separately, as in... Figure 32The horizontal arrow indicates this. In this regard, scanning can be performed with different focus settings or with modulated energy density distributions.

[0122] After that, as Figure 34 and Figure 35 As shown, selective wet chemical etching of the initial substrate 115 is performed using a wet chemical etchant 257, thereby providing the initial substrate 115 with an optical lens shape. This forms a corresponding lens shape or lens-like segment in the region of each semiconductor layer sequence 150. Here, a localized laser irradiation and etching process is performed, allowing monolithization without etching. The wet chemical etchant 257 can be an aqueous solution of hydrofluoric acid. Through etching, the amorphous substrate region 255 is selectively removed or dissolved, which further results in the removal of the crystalline portion of the initial substrate 115 used to form the planar front side 112, thereby producing the target lens shape. The etching process results in... Figure 35 The initial substrate 115 shown constitutes an assembly of multiple connected chip substrates 110, each chip substrate 110 having a corresponding lenticular segment. As depicted, the lenticular segment may be in the form of a hemispherical shape 121.

[0123] Subsequently, as Figure 36 As shown, monolithization is performed where the initial substrate 115 is cut at corresponding separation lines 220 in the region between the hemispherical shapes 121, thereby producing individual LED chips 100, each LED chip 100 including a chip substrate 110. Monolithization can be performed by sawing or by laser scribing followed by breaking. In addition to the lenticular segments having hemispherical shapes 121, the chip substrate 110 also includes a base segment 130. The base segment 130 can be cubic. This can be the case when monolithization is performed using a rectangular or square separation pattern. Depending on the laser-induced etching performed, a transition can exist between the base segment 130 and the lenticular segments including the hemispherical shapes 121, such that a similar transition can exist. Figure 10 The configuration shown, or the base segment 130, can be adjacent to the lens-shaped segment, allowing for a configuration similar to... Figure 12 The configuration shown is the configuration.

[0124] The modification of the aforementioned method sequence produces other lens shapes. To illustrate, Figure 37 and Figure 38 Another method sequence for generating the LED chip 100, representing a possible modification of the aforementioned method sequence, is shown. Here, the method sequence referred to above is also performed first. Figures 18 to 20The process is explained to obtain an initial substrate 115 with semiconductor layer sequences 150 and contact elements 160, and then selective laser-induced etching of the initial substrate 115 is performed. This results in the initial substrate 115 after etching comprising lens-shaped or lens-like segments in the form of Fresnel lens structures 125, with corresponding Fresnel lens structures 125 formed in the region of each semiconductor layer sequence 150, such as... Figure 37 As shown. Furthermore, front-side trenches 260 are formed in the initial substrate 125 together with the Fresnel lens structures 125 via laser-induced etching. The trenches 260 are located in the regions between and around the Fresnel lens structures 125, and can exist in the form of a continuous trench structure. The trenches 260 facilitate subsequent monolithization of the initial substrate 115 to provide independent LED chips 100, such as... Figure 37 As shown. The resulting LED chip 100 may include similar... Figure 11 The configuration described in the text.

[0125] The aforementioned modification to the laser-induced etching method sequence involves performing laser-induced etching such that not only is a lens shape formed, but also monolithization is achieved. In this way, via etching, the initial substrate 115 is additionally separated into individual LED chips 100 (not depicted). Such LED chips 100 may comprise, for example, [e.g., according to or similar to...] Figure 1 The configuration shown is the configuration.

[0126] Figures 39 to 42 Another possible sequence of methods for producing LED chip 100 is shown. In this method, such as... Figure 39 As shown, an initial substrate 115 is provided on which semiconductor layer sequences 150 are arranged adjacent to each other on a rear side 111, and contact elements 160 are provided on the semiconductor layer sequences 150. The initial substrate 115 also includes trenches 270 formed on the rear side 111. The trenches 270 are located in the regions between and around the semiconductor layer sequences 150, and may exist in the form of a continuous trench structure. The formation of the semiconductor layer sequences 150 and the contact elements 160 can be as described above. Figures 18 to 20 The process is as described. The rear trench 270 can be formed by laser-induced etching. Here, for example, the initial substrate 115 can be irradiated with laser radiation before or after the initial semiconductor layer sequence 155 is formed on the initial substrate 115, and then the semiconductor layer sequence 150 is generated from the initial semiconductor layer sequence 155 by structuring, wherein the laser radiation can be directed to the front side 112 of the initial substrate 115. The etching of the trench 270 can be performed after the initial semiconductor layer sequence 155 is structured into a separate semiconductor layer sequence 150 (not depicted).

[0127] Subsequently, a reflective layer 175 is formed at least on the sidewalls of the trench 270, and, if applicable, on the bottom of the trench 270, such as... Figure 40 The reflective layer 175 may comprise a metallic material or a combination of a metallic material and a dielectric material. Subsequently, the initial substrate 115 undergoes laser-induced etching again. In the present case, this is done such that the initial substrate 115 remaining after etching includes lens-shaped or lenticular segments in the form of hemispherical shapes 121, with corresponding hemispherical shapes 121 formed in the region of each semiconductor layer sequence 150, such as... Figure 41 As shown. This is followed by monolithization, where the initial substrate 115 is cut at corresponding separation lines 220 in the region between the hemispherical shapes 121 and in the region of the trench 270, as... Figure 41 As shown, this produces individual LED chips 100, each including a chip substrate 110. The chip substrate 110 includes a lens-shaped segment having a hemispherical shape 121 and a base segment 130 that may be cubic. The LED chip 100 also includes a reflective layer 175 extending to the rear side 111 of the associated chip substrate 110. The reflective layer 175 is disposed on the base segment 130 and may thus exist on the periphery or lateral sidewalls of the base segment 130. In illumination operation, the reflective layer 175 can act as a reflector, through which lateral radiative emission in the region of the base segment 130 can be suppressed.

[0128] Figures 39 to 42 Variations of the method sequence are to produce other lens shapes. Furthermore, etching can be performed to not only form the lens shape but also monolithize it, or, for monolithization, to remove or cut only a portion (not depicted) of the reflective layer 111.

[0129] Regarding the chip substrate 110 of the LED chip 100, a complex design can be provided, in which curvatures with different curvature directions can exist, and therefore, convex and concave curved portions of the surface can exist. For illustration, Figure 43 Another configuration of the LED chip 100 is shown, which includes a chip substrate 110 having an optical lens shape realized by or in the form of an annular lens shape 128. Here, the chip substrate 110 includes a substantially convexly curved lens-shaped body similar to a partially ellipsoidal or partially sphere, having a concavely curved recess 138 in the central region. In this configuration, radiation broadening of the emitted light radiation can be achieved by the chip substrate 110 (not depicted).

[0130] Figure 43The chip substrate 110 of the LED chip 100 shown may include rotational symmetry with respect to a longitudinal axis 205 perpendicular to the rear side 111 of the chip substrate 110. The rear side 111 of the chip substrate 110, on which the semiconductor layer sequence 150 is disposed, may include a circular profile. In this way, a corresponding... Figure 1 or Figure 3 The horizontal cross-sectional view shown is located at the rear side 111.

[0131] Figure 43 Possible modifications to the LED chip 100 shown include: providing the aforementioned features in the chip substrate 110, such as a transition from a square or rectangular outline in the direction away from the rear side 111, and / or providing a rear base segment 130 constituting the rear side 111. In order to produce... Figure 43 The LED chip 100 depicted herein, or its possible modifications, can perform the aforementioned production method, such as involving laser-induced etching and corresponding to Figures 32 to 36 The method sequence (not depicted).

[0132] In addition to the embodiments described above and depicted in the accompanying drawings, other embodiments are conceivable, which may include further modifications and / or combinations of features.

[0133] In this regard, the information about materials given above is considered exemplary, allowing the specified material to be substituted with other materials. The same applies to the specified numerical information and the specified optical radiation.

[0134] As an example, the chip substrate 110 can also be made of silicon carbide, gadolinium gallium garnet, quartz, or a semiconductor material such as gallium arsenide. The same applies to the initial substrate 115. The semiconductor layer sequence 150 and the initial semiconductor layer sequence 155 can also be configured to generate blue, green, red, or infrared light radiation, which can be achieved using a suitable semiconductor material system, including III-V compound semiconductor materials (including elements from Group III and Group V of the periodic table).

[0135] In addition to the shapes described and shown in the accompanying drawings, other shapes may be considered for the chip substrate 110 and the corresponding lens shape. As an example, Figure 36 The base segment 130 of the chip substrate 110 shown may not be a cube, but instead a prism with a corresponding polygonal outline in a planar view. This depends on the monolithization being performed. In this regard, it is possible to consider... Figure 13 The outline depicted can be achieved by applying hexagonal or triangular separation patterns.

[0136] Regarding the production method, in addition to the steps described, other method steps may be performed. This may include, for example, forming an anti-reflective layer 170, such as...Figure 9 The LED chip 100 is depicted in the diagram. Such an anti-reflective layer 170 can be formed on the chip substrate 110 after the individual LED chips 100 are produced. Regarding the above-described method sequence of performing additional monolithization after forming the lens shape, i.e. Figure 25 and Figure 26 , Figures 32 to 36 , Figure 37 and Figure 38 as well as Figures 39 to 42 The process shown allows for the formation of an anti-reflective layer 170 on the processed initial substrate 115 in a lens-shaped region before monolithization. Therefore, this method simplifies the fabrication of the LED chip 100 with the anti-reflective layer 170. During this process, with... Figure 9 Unlike other layers, the anti-reflective layer 170 may not extend to the rear side 111 (not shown) of the chip substrate 110.

[0137] Another possible step is to provide a dielectric passivation layer for the sidewalls of the semiconductor layer sequence 150 or multiple semiconductor layer sequences 150. Such a layer can be formed, for example, after the initial semiconductor layer sequence 155 has been structured (not depicted).

[0138] Regarding the methods for generating laser-induced etching, vapor phase etching can be used to replace wet chemical etching.

[0139] Furthermore, the method described herein is not limited to radiation-emitting optoelectronic semiconductor chips or LED chips, but can also be applied to radiation-detecting optoelectronic semiconductor chips. Such a radiation-detecting semiconductor chip 100 can have the configuration shown above and in the figures, and thus includes a front-side radiation-transmitting chip substrate 110 with an optical lens shape, a rear-side semiconductor layer sequence 150 disposed on the chip substrate 110, and two rear-side metal contact elements 160 connected to the semiconductor layer sequence 150. The semiconductor layer sequence 150 or its active region can be configured to detect light radiation such as ultraviolet radiation. In this way, the radiation-detecting semiconductor chip 100 can be used to implement detectors such as solar-blind UV detectors. In detection operation, light radiation from the external environment can be coupled into the chip substrate 110 and propagate through it to the semiconductor layer sequence 150, and thus the electrical energy generated by the semiconductor layer sequence 150 can be utilized via the contact elements 160. Here, the lens-shaped chip substrate 110 makes it possible to reduce back reflection at the interface between the chip substrate 110 and the external environment or air, and thus provides effective coupling (not depicted) of light radiation into the chip substrate 110.

[0140] Although the invention has been described and illustrated in more detail with the aid of preferred exemplary embodiments, the invention is not limited to the disclosed examples, and those skilled in the art can derive other variations therefrom without departing from the scope of protection of the invention.

[0141] Figure Labels

[0142] 100 Optoelectronic Semiconductor Chips

[0143] 110 chip substrate

[0144] 111 rear side

[0145] 112 front side

[0146] 115 initial substrate

[0147] 120 semi-ellipsoidal shape

[0148] 121 Hemispherical shape

[0149] 122 Semi-ellipsoidal shape

[0150] 123 Semi-ellipsoidal shape

[0151] 124-facet lens structure

[0152] 125 Fresnel lens structure

[0153] 127 dome shape

[0154] 128 ring lens shape

[0155] 130 base section

[0156] 134 partial surfaces

[0157] 135 part surface

[0158] 136 surface

[0159] 137 partial surfaces

[0160] 138 depression

[0161] 150 semiconductor layer sequence

[0162] 155 Initial Semiconductor Layer Sequence

[0163] 160 contact element

[0164] 170 anti-reflective layer

[0165] 175 reflective layer

[0166] 200 thickness

[0167] 201 thickness

[0168] 202 width

[0169] 205 longitudinal axis

[0170] 207 Protrusion

[0171] 210 light radiation

[0172] 220 separation line

[0173] 230 tools

[0174] 231 tools

[0175] 240 photoresist

[0176] 245 Etching Effect

[0177] 250 laser radiation

[0178] 255 amorphous region

[0179] 257 Wet Chemical Etching Agent

[0180] 260 groove

[0181] 270 trench

Claims

1. An optoelectronic semiconductor chip (100), comprising: a front-side radiation-transmissive chip substrate (110); a back-side semiconductor layer sequence (150) arranged on the chip substrate (110), the semiconductor layer sequence (150) being configured for radiation emission or radiation detection, and the semiconductor layer sequence (150) directly adjoining the chip substrate (110); and a back-side contact element (160) for contacting the semiconductor layer sequence (150), wherein the chip substrate (110) is integrally formed in a lens shape deviating from a cubic shape.

2. The optoelectronic semiconductor chip according to claim 1, the chip substrate (110) comprising at least in partial regions one of: wherein a partial ellipsoid or partial sphere shape; a half-ellipsoid or half-sphere shape (120, 121, 122, 123); a Fresnel lens structure (125); and / or a facet lens structure (124).

3. The optoelectronic semiconductor chip according to any one of the preceding claims, the chip substrate (110) comprising at least in partial regions a dome shape (127) formed by a plurality of adjoining curved partial surfaces (137), the curved partial surfaces (137) being triangular and converging to a vertex. wherein 4. The optoelectronic semiconductor chip according to any one of the preceding claims, the chip substrate (110) comprising a transition from a polygonal contour to an elliptical or circular contour in a direction away from the semiconductor layer sequence (150). wherein 5. The optoelectronic semiconductor chip according to any one of the preceding claims, the chip substrate (110) comprising a base section (130) on which the semiconductor layer sequence (150) is arranged, and wherein the base section (130) comprises a polygonal contour at least in a region of the semiconductor layer sequence (150). wherein 6. The optoelectronic semiconductor chip according to any one of the preceding claims, further comprising a reflective layer (175) arranged on the chip substrate (110).

7. The optoelectronic semiconductor chip according to any one of the preceding claims, further comprising an anti-reflective layer (170) arranged on the chip substrate (110).

8. The optoelectronic semiconductor chip according to any one of the preceding claims, the semiconductor layer sequence (150) comprising one of: wherein a polygonal contour; or an elliptical or circular contour.

9. The optoelectronic semiconductor chip according to any one of the preceding claims, the semiconductor layer sequence (150) being a layer sequence grown on the chip substrate (110). wherein 10. A method for producing at least one optoelectronic semiconductor chip (100), the optoelectronic semiconductor chip (100) comprising a front-side radiation-transmissive chip substrate (110), a back-side semiconductor layer sequence (150) arranged on the chip substrate (110), and a back-side contact element (160) for contacting the semiconductor layer sequence (150), the semiconductor layer sequence (150) being configured for radiation emission or radiation detection and directly adjoining the chip substrate (110), wherein ​ and wherein, in the method, the chip substrate (110) is integrally formed in a lens shape deviating from a cubic shape.

11. The method according to claim 10, wherein, In the method, the semiconductor layer sequence (150) is produced by one of: - growing the semiconductor layer sequence (150) on the chip substrate (110); or - growing a larger initial semiconductor layer sequence (155) on a radiation- transmissive initial substrate (115) which is provided for a plurality of optoelectronic semiconductor chips (100) manufactured together, and subsequently structuring the initial semiconductor layer sequence (155) into a plurality of semiconductor layer sequences (150) arranged next to each other on the initial substrate (115), the plurality of semiconductor layer sequences (150) being provided for the plurality of optoelectronic semiconductor chips (100), and the chip substrate (110) subsequently being produced from the initial substrate (115).

12. The method according to any one of claims 10 or 11, wherein The chip substrate (110) is provided with the lens shape, and subsequently the semiconductor layer sequence (150) and the contact element (160) are formed arranged on the chip substrate (110).

13. The method according to any one of claims 10 or 11, wherein The optoelectronic semiconductor chip (100) is provided such that the chip substrate (110) comprises an initial shape, and subsequently the lens shape is formed by processing the chip substrate (110).

14. The method according to any one of claims 10 or 11, wherein A plurality of optoelectronic semiconductor chips (100) is produced together, wherein a radiation-transmissive initial substrate (115) is provided, on which a plurality of semiconductor layer sequences (150) is arranged, the plurality of semiconductor layer sequences (150) being provided with contact elements (160) for the plurality of optoelectronic semiconductor chips (100), and wherein subsequently a lens shape for the plurality of optoelectronic semiconductor chips (100) is formed by processing the initial substrate (115).

15. The method according to claim 14, wherein After the processing of the initial substrate (115), singulation is performed to provide the plurality of optoelectronic semiconductor chips (100).

16. The method according to claim 14, wherein The processing of the initial substrate (115) is accompanied by singulation for providing the plurality of optoelectronic semiconductor chips (100).

17. The method according to any one of claims 14 to 16, wherein The processing of the initial substrate (115) is performed mechanically.

18. The method according to any one of claims 14 to 16, wherein, The processing of the initial substrate (115) is performed by etching.

19. The method according to claim 18, wherein, Prior to the etching, the initial substrate (115) is locally modified by irradiation with laser radiation (250) for predetermining the lens shape.

20. The method according to any one of claims 14 to 19, wherein, at the side of the initial substrate (115) on which the semiconductor layer sequence (150) is arranged, a trench (270) is formed, and wherein subsequently a reflective layer (175) is formed at least on the side walls of the trench (270).

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