Method for manufacturing light-emitting elements

Abstract

To provide a method for manufacturing a light-emitting element having high reliability.SOLUTION: A method for manufacturing a light-emitting element includes the steps of: forming a first mask on a light-transmitting conductive film; removing the light-transmitting conductive film exposed from the first mask to form an opening in the light-transmitting conductive film, the opening exposing a semiconductor structure; forming an n-side exposed part where part of an n-side layer is exposed from a p-side layer and an active layer, by removing the semiconductor structure exposed from the first mask; removing the first mask; forming a second mask on the light-transmitting conductive film, at a position separated from an outer edge of the light-transmitting conductive film defining the opening in a top view; removing the light-transmitting conductive film exposed from the second mask to expose the p-side layer from the light-transmitting conductive film; forming a third mask on the light-transmitting conductive film and on the semiconductor structure; and removing the semiconductor structure in a region not overlapping the third mask to form a groove in the semiconductor structure, the groove dividing the semiconductor structure into a plurality of element parts.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a light-emitting element.

Background Art

[0002] For example, Patent Document 1 discloses a light-emitting element in which a transparent conductive film is formed on a nitride semiconductor structure.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a method for manufacturing a highly reliable light-emitting element.

Means for Solving the Problems

[0005] According to one aspect of the present invention, a method for manufacturing a light-emitting element includes the steps of: preparing a wafer having an n-side layer, an active layer disposed on the n-side layer, a p-side layer disposed on the active layer, and a translucent conductive film disposed on the p-side layer; forming a first mask on the translucent conductive film; after forming the first mask, removing the translucent conductive film exposed from the first mask and forming an opening in the translucent conductive film that exposes the semiconductor structure from the translucent conductive film; after removing the translucent conductive film exposed from the first mask, removing the semiconductor structure exposed from the first mask and forming an n-side exposed portion in which a part of the n-side layer is exposed from the p-side layer and the active layer; and after forming the n-side exposed portion, the first mask The process includes: removing the first mask; forming a second mask on the translucent conductive film at a position away from the outer edge defining the opening of the translucent conductive film in a plan view, after the first mask has been removed; removing the translucent conductive film exposed from the second mask after the second mask has been formed to expose the p-side layer from the translucent conductive film; forming an n-side electrode on the n-side exposed portion; forming a third mask on the translucent conductive film and the semiconductor structure after the second mask has been removed; and removing the semiconductor structure in a region that does not overlap with the third mask in a plan view after the third mask has been formed to form grooves in the semiconductor structure that separate the semiconductor structure into multiple element portions. [Effects of the Invention]

[0006] According to the present invention, a highly reliable method for manufacturing a light-emitting element can be provided. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic plan view illustrating one step in the manufacturing method of a light-emitting element according to an embodiment. [Figure 2] This is a schematic cross-sectional view along line II-II in Figure 1. [Figure 3]This is a schematic plan view illustrating one step in the manufacturing method of a light-emitting element according to an embodiment. [Figure 4] Figure 3 is a schematic cross-sectional view along line IV-IV. [Figure 5] This is a schematic plan view illustrating one step in the manufacturing method of a light-emitting element according to an embodiment. [Figure 6] Figure 5 is a schematic cross-sectional view along the line VI-VI. [Figure 7] This is a schematic plan view illustrating one step in the manufacturing method of a light-emitting element according to an embodiment. [Figure 8] Figure 7 is a schematic cross-sectional view along the line VIII-VIII. [Figure 9] This is a schematic plan view illustrating one step in the manufacturing method of a light-emitting element according to an embodiment. [Figure 10] Figure 9 is a schematic cross-sectional view along line XX. [Figure 11] Figure 9 is a schematic cross-sectional view along the line XI-XI. [Figure 12] This is a schematic plan view illustrating one step in the manufacturing method of a light-emitting element according to an embodiment. [Figure 13] Figure 12 is a schematic cross-sectional view along the line XIII-XIII. [Figure 14] Figure 12 is a schematic cross-sectional view along line XIV-XIV. [Figure 15] This is a schematic plan view illustrating one step in the manufacturing method of a light-emitting element according to an embodiment. [Figure 16] Figure 15 is a schematic cross-sectional view along the line XVI-XVI. [Figure 17] Figure 15 is a schematic cross-sectional view along the line XVII-XVII. [Figure 18] This is a schematic plan view illustrating one step in the manufacturing method of a light-emitting element according to an embodiment. [Figure 19] Figure 18 is a schematic cross-sectional view of the XIX-XIX line. [Figure 20] Figure 18 is a schematic cross-sectional view along the line XX-XX. [Figure 21]It is a schematic plan view for explaining one step of the method for manufacturing a light-emitting element according to an embodiment. [Figure 22] It is a schematic cross-sectional view taken along line XXII-XXII of FIG. 21. [Figure 23] It is a schematic cross-sectional view taken along line XXIII-XXIII of FIG. 21. [Figure 24] It is a schematic plan view for explaining one step of the method for manufacturing a light-emitting element according to an embodiment. [Figure 25] It is a schematic cross-sectional view taken along line XXV-XXV of FIG. 24. [Figure 26] It is a schematic cross-sectional view taken along line XXVI-XXVI of FIG. 24. [Figure 27] It is a schematic plan view for explaining one step of the method for manufacturing a light-emitting element according to an embodiment. [Figure 28] It is a schematic cross-sectional view taken along line XXVIII-XXVIII of FIG. 27. [Figure 29] It is a schematic plan view for explaining one step of the method for manufacturing a light-emitting element according to an embodiment. [Figure 30] It is a schematic cross-sectional view taken along line XXX-XXX of FIG. 29. [Figure 31] It is a schematic cross-sectional view for explaining one step of the method for manufacturing a light-emitting element according to an embodiment. [Figure 32] It is a schematic cross-sectional view for explaining one step of the method for manufacturing a light-emitting element according to an embodiment. [Figure 33] It is a schematic plan view for explaining one step of the method for manufacturing a light-emitting element according to an embodiment. [Figure 34] It is a schematic cross-sectional view taken along line XXXIV-XXXIV of FIG. 33. [Figure 35] It is a schematic cross-sectional view for explaining one step of the method for manufacturing a light-emitting element according to an embodiment. [Figure 36] It is a schematic cross-sectional view for explaining one step of the method for manufacturing a light-emitting element according to an embodiment. [Figure 37] It is a schematic cross-sectional view for explaining one step of the method for manufacturing a light-emitting element according to an embodiment. [Figure 38]This is a schematic cross-sectional view illustrating one step in the manufacturing method of a light-emitting element according to an embodiment. [Figure 39] This is a schematic cross-sectional view illustrating one step in the manufacturing method of a light-emitting element according to an embodiment. [Figure 40] This is a schematic cross-sectional view illustrating one step in the manufacturing method of a light-emitting element according to an embodiment. [Figure 41] This is a schematic cross-sectional view illustrating one step in the manufacturing method of a light-emitting element according to an embodiment. [Figure 42] This is a schematic plan view of the light-emitting element of the embodiment. [Modes for carrying out the invention]

[0008] The embodiments will be described below with reference to the drawings. The dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments are not intended to be limiting unless otherwise specified, but are merely illustrative examples. The size and positional relationships of the members shown in each drawing may be exaggerated for clarity of explanation. In addition, in the following description, the same name and reference numeral indicate the same or identical member, and detailed explanations will be omitted as appropriate. In addition, in some cases, end view diagrams showing only the cut surface will be shown as cross-sectional views.

[0009] In the following description, terms indicating specific directions or positions (e.g., "up," "down," and other terms including these) may be used. However, these terms are used merely for clarity to indicate the relative directions or positions in the referenced drawings. If the relative direction or position relationship indicated by terms such as "up" and "down" in the referenced drawings is the same, the arrangement in drawings other than those disclosed, actual products, etc., does not have to be the same as in the referenced drawings. In this specification, the positional relationship expressed as "up (or down)" includes, for example, the case where two members are in contact with each other, and the case where the two members are not in contact but one member is located above (or below) the other member. Furthermore, unless otherwise specified, "a member covers an object" includes the case where the member is in contact with the object and directly covers it, and the case where the member does not contact the object and indirectly covers it.

[0010] In the diagrams shown below, directions may be indicated by the X, Y, and Z axes. The X, Y, and Z axes are orthogonal to each other. For example, in this specification, the direction along the X axis is referred to as the first direction X, the direction along the Y axis as the second direction Y, and the direction along the Z axis as the third direction Z.

[0011] <Wafer preparation process> The manufacturing method for the light-emitting element of this embodiment includes a step of preparing the wafer W shown in Figures 1 and 2. Figures 1 and 2 show a portion of the wafer W. Figures 3 and subsequent drawings, which show the steps following Figures 1 and 2, also show a portion of the wafer W.

[0012] As shown in Figure 2, wafer W has a semiconductor structure 10 and a translucent conductive film 15. Wafer W also has a first substrate 101 used to form the semiconductor structure 10. Wafer W does not necessarily have to have the first substrate 101.

[0013] The semiconductor structure 10 is made of a nitride semiconductor. In this specification, "nitride semiconductor" means, for example, In x Al y Ga 1-x-yThis term includes semiconductors with all compositions obtained by varying the composition ratios x and y within the respective ranges in the chemical formula N(0≦x≦1,0≦y≦1,x+y≦1). Furthermore, "nitride semiconductors" also include those that further contain group V elements other than N (nitrogen) in the above chemical formula, and those that further contain various elements added to control various physical properties such as conductivity.

[0014] The semiconductor structure 10 has an n-side layer 11, an active layer 13 disposed on the n-side layer 11, and a p-side layer 12 disposed on the active layer 13. The active layer 13 is located between the n-side layer 11 and the p-side layer 12 in the third direction Z. The active layer 13 is a light-emitting layer and has, for example, an MQW (Multiple Quantum Well) structure including multiple barrier layers and multiple well layers. The active layer 13 emits, for example, light with a peak wavelength of 210 nm to 580 nm. The n-side layer 11 has a semiconductor layer containing n-type impurities. The p-side layer 12 has a semiconductor layer containing p-type impurities.

[0015] For example, an n-side layer 11, an active layer 13, and a p-side layer 12 are sequentially formed on the first substrate 101 by the MOCVD (Metal Organic Chemical Vapor Deposition) method. The first substrate 101 can be an insulating substrate such as sapphire or spinel (MgA12O4) with one of the C-plane, R-plane, or A-plane as the main surface. Alternatively, a conductive substrate such as SiC (including 6H, 4H, and 3C), ZnS, ZnO, GaAs, or Si may be used as the first substrate 101. In this embodiment, a sapphire substrate with the C-plane as the main surface is used as the first substrate 101.

[0016] The translucent conductive film 15 is placed on the p-side layer 12. The translucent conductive film 15 is formed, for example, by sputtering or vapor deposition. As the material for the translucent conductive film 15, for example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), ZnO, In2O3, etc. can be used. The translucent conductive film 15 has the function of diffusing the current supplied through the p-side electrode 32, which will be described later, in the planar direction of the p-side layer 12. The thickness of the translucent conductive film 15 can be, for example, 0.03 μm or more and 0.2 μm or less. In this specification, the "thickness" of each component refers to the maximum thickness in the third direction Z.

[0017] <Process for forming the first mask> The manufacturing method for the light-emitting element of this embodiment includes a step of preparing a wafer W, followed by a step of forming a first mask 91 on a translucent conductive film 15, as shown in Figures 3 and 4.

[0018] For example, a photoresist can be used for the first mask 91. By exposure and development processing, a plurality of mask openings 91a are formed in the first mask 91. In a plan view, the plurality of mask openings 91a are separated from each other in the first direction X and the second direction Y. The translucent conductive film 15 is exposed from the first mask 91 at the mask openings 91a.

[0019] <Step to remove the translucent conductive film exposed from the first mask> The manufacturing method for the light-emitting element of the embodiment includes, after the step of forming a first mask 91, the step of removing the translucent conductive film 15 exposed from the first mask 91, as shown in Figures 5 and 6, and forming an opening 15a in the translucent conductive film 15 that exposes the semiconductor structure 10 from the translucent conductive film 15. As shown in Figure 5, in a plan view, the opening 15a is formed at a position that overlaps with the mask opening 91a. Multiple openings 15a are spaced apart from each other in the first direction X and the second direction Y. At the opening 15a, the upper surface of the p-side layer 12 is exposed from the translucent conductive film 15.

[0020] The transparent conductive film 15 is preferably removed by wet etching. By removing the transparent conductive film 15 by wet etching, it is easier to process many wafers simultaneously compared to the case of removing the transparent conductive film 15 by dry etching, so the productivity can be improved. As the etching solution used for wet etching, for example, hydrochloric acid, nitric acid, a mixed solution of hydrochloric acid and nitric acid, etc. can be used.

[0021] <Step of forming n-side exposed portion> In the method for manufacturing a light-emitting element according to the embodiment, after the step of removing the transparent conductive film 15 exposed from the first mask 91, as shown in FIGS. 7 and 8, the semiconductor structure 10 exposed from the first mask 91 is removed, and a step of forming an n-side exposed portion 11a in which a part of the n-side layer 11 is exposed from the p-side layer 12 and the active layer 13 is provided.

[0022] As shown in FIG. 7, in a plan view, the n-side exposed portion 11a is formed at a position overlapping the mask opening 91a and the opening 15a of the transparent conductive film 15. A plurality of n-side exposed portions 11a are spaced apart from each other in the first direction X and the second direction Y.

[0023] In the step of forming the n-side exposed portion 11a, it is preferable to remove the semiconductor structure 10 exposed from the first mask 91, for example, by dry etching. By removing the semiconductor structure 10 by dry etching, it is easy to control the removal amount of the semiconductor structure 10. The p-side layer 12 and the active layer 13 exposed from the first mask 91 in the mask opening 91a are removed, and a part of the n-side layer 11 is exposed from the transparent conductive film 15, the p-side layer 12, and the active layer 13 to form the n-side exposed portion 11a. Examples of the dry etching method include the RIE (Reactive Ion Etching) method. For the RIE method at this time, for example, a gas containing chlorine can be used, and gases such as Cl2 and SiCl4 can be used.

[0024] The process of removing the translucent conductive film 15 exposed from the first mask 91 and the process of removing the semiconductor structure 10 exposed from the first mask 91 may be performed using the same etching method.

[0025] <Step to remove the first mask> The manufacturing method for the light-emitting element of this embodiment includes a step of removing the first mask 91 after the step of forming the n-side exposed portion 11a. For example, the first mask 91 is removed using an organic solvent or ozonated water. The removal of the first mask 91 may also be performed by ashing with oxygen plasma.

[0026] <Process for forming the second mask> The manufacturing method for the light-emitting element of this embodiment includes a step of removing the first mask 91, followed by a step of forming a second mask 92 on the light-transmitting conductive film 15, as shown in Figures 9 to 11.

[0027] For example, a photoresist can be used for the second mask 92. By exposure and development processing, a plurality of second masks 92 are formed that are separated from each other in the first direction X and the second direction Y in a plan view.

[0028] As shown in Figures 9 to 11, the translucent conductive film 15 located between adjacent second masks 92 in the first direction X and the second direction Y is exposed from the second masks 92. Furthermore, the second masks 92 are formed on the translucent conductive film 15 at a position away from the outer edge 15o that defines the opening 15a of the translucent conductive film 15 in a plan view. In a plan view, the second masks 92 do not overlap the outer edge 15o that defines the opening 15a of the translucent conductive film 15.

[0029] <Step to remove the translucent conductive film exposed from the second mask> The manufacturing method for the light-emitting element of this embodiment includes a step of forming a second mask 92, followed by a step of removing the translucent conductive film 15 exposed from the second mask 92. This step exposes the p-side layer 12 from the translucent conductive film 15, as shown in Figures 12 to 14. In Figure 12, the region in which the p-side layer 12 is exposed from the translucent conductive film 15 as a result of the step of removing the translucent conductive film 15 exposed from the second mask 92 is shown with shading.

[0030] Furthermore, as shown in Figures 12 and 13, the process of removing the translucent conductive film 15 exposed from the second mask 92 forms a plurality of translucent conductive films 15 that are spaced apart from each other in the first direction X and the second direction Y in a plan view. Each translucent conductive film 15 is located between the second mask 92 and the p-side layer 12.

[0031] In the step of removing the translucent conductive film 15 exposed from the second mask 92, it is preferable to remove the translucent conductive film 15 by wet etching, similar to the step of removing the translucent conductive film 15 exposed from the first mask 91. The same etching solution can be used in the step of removing the translucent conductive film 15 exposed from the first mask 91 and the step of removing the translucent conductive film 15 exposed from the second mask 92.

[0032] In the steps of removing the translucent conductive film 15 exposed from the first mask 91 and removing the translucent conductive film 15 exposed from the second mask 92, the ease with which the etching solution penetrates differs due to the difference in the planar shapes of the first mask 91 and the second mask 92. Therefore, it is preferable to use different wet etching times in the steps of removing the translucent conductive film 15 exposed from the first mask 91 and removing the translucent conductive film 15 exposed from the second mask 92.

[0033] In this embodiment, in the step of forming the first mask 91, a first mask 91 having a plurality of mask openings 91a is formed as shown in Figure 3. In the step of forming the second mask 92, a plurality of second masks 92 spaced apart from each other are formed as shown in Figure 12. Because the second masks 92 are spaced apart from each other, the etching solution can easily flow around to the outer edge side in a plan view of the second masks 92, and etching of the translucent conductive film 15 proceeds more easily than in the removal step of the translucent conductive film 15 using the first mask 91 into which the etching solution penetrates only through the mask openings 91a. Conversely, in the step of removing the translucent conductive film 15 exposed from the first mask 91, etching of the translucent conductive film 15 proceeds less easily than in the step of removing the translucent conductive film 15 exposed from the second mask 92. Therefore, it is preferable that the wet etching time in the step of removing the translucent conductive film 15 exposed from the first mask 91 be longer than the wet etching time in the step of removing the translucent conductive film 15 exposed from the second mask 92.

[0034] <Step to remove the second mask> The manufacturing method for the light-emitting element of the embodiment includes a step of removing the light-transmitting conductive film 15 exposed from the second mask 92, followed by a step of removing the second mask 92. The second mask 92 can be removed by the same method as the method for removing the first mask 91.

[0035] <Process for forming electrodes> The manufacturing method for the light-emitting element of this embodiment includes a step of forming an n-side electrode 31 on the n-side exposed portion 11a after removing the second mask 92, as shown in Figures 15 and 16. The n-side electrode 31 is formed on the n-side exposed portion 11a and is electrically connected to the n-side layer 11. Furthermore, as shown in Figures 15 and 17, the manufacturing method for the light-emitting element of this embodiment includes a step of forming a p-side electrode 32 on the translucent conductive film 15 after removing the second mask 92. The p-side electrode 32 is electrically connected to the p-side layer 12 via the translucent conductive film 15.

[0036] The n-side electrode 31 and the p-side electrode 32 are formed, for example, by sputtering or vapor deposition. The n-side electrode 31 and the p-side electrode 32 can be, for example, a single layer of metal containing Ti, Rh, Au, Pt, Al, Ag, Rh, or Ru, or a laminated structure containing at least two of these metal layers. The n-side electrode 31 and the p-side electrode 32 can be formed simultaneously using the same material.

[0037] According to this embodiment, as shown in Figure 9, the second mask 92 is formed at a position away from the outer edge 15o that defines the opening 15a of the translucent conductive film 15 in a plan view. By using this second mask 92 to remove the translucent conductive film 15 exposed from the second mask 92, the translucent conductive film 15 is formed in multiple regions separated from each other, corresponding to the position of the second mask 92. As shown in Figure 15, each of the multiple translucent conductive films 15 is formed at a position away from the outer edge 11o of the n-side exposed portion 11a in a plan view. This makes it possible to increase the distance between the translucent conductive film 15 to which the potential is applied and the n-side exposed portion 11a to which the potential is applied. As a result, electrostatic discharge breakdown of the light-emitting element is less likely to occur, and the reliability of the light-emitting element can be increased.

[0038] For example, in the process of forming the n-side exposed portion 11a, after removing the translucent conductive film 15 and the semiconductor structure 10, the wafer W is further immersed in an etching solution to allow the etching solution to penetrate the translucent conductive film 15 located below the first mask 91. This removes a portion of the translucent conductive film 15 located below the first mask 91, increasing the distance between the outer edge of the translucent conductive film 15 and the n-side exposed portion 11a. However, the shape of the outer edge of the translucent conductive film 15 formed by this method tends to be uneven, which can lead to variations in the performance of the manufactured light-emitting element. According to this embodiment, the unevenness of the shape of the outer edge of the translucent conductive film 15 can be reduced, thereby reducing variations in the performance of the light-emitting element.

[0039] In a plan view, the longer the shortest distance d1 between the outer edge 11o of the n-side exposed portion 11a and the outer edge 15b of the translucent conductive film 15 facing the outer edge 11o of the n-side exposed portion 11a, the less likely electrostatic discharge (ESD) breakdown of the light-emitting element is to occur. However, if the shortest distance d1 is increased based on the position of the outer edge 11o of the n-side exposed portion 11a, the area of ​​the translucent conductive film 15 is reduced. When the area of ​​the translucent conductive film 15 decreases, the region in the p-side layer 12 to which current is directly supplied from the translucent conductive film 15 decreases, which can lead to a reduction in the effective light-emitting region. Therefore, in order to secure a wider light-emitting region while making electrostatic discharge breakdown of the light-emitting element less likely, it is preferable that the shortest distance d1 be 1 μm or more and 5 μm or less.

[0040] <Process for forming the first reflective layer> The manufacturing method for the light-emitting element of this embodiment may include a step of forming a first reflective layer 40 as needed, after forming the n-side electrode 31 and the p-side electrode 32, as shown in Figures 18 to 20. The first reflective layer 40 covers the surface of the semiconductor structure 10 that is opposite to the surface that is located on the first substrate 101 side. The first reflective layer 40 also covers the translucent conductive film 15, the n-side electrode 31, and the p-side electrode 32.

[0041] The first reflective layer 40 has reflectivity to light emitted by the active layer 13. The first reflective layer 40 includes, for example, a dielectric multilayer film. The dielectric multilayer film includes, for example, alternately stacked SiO2 layers and Nb2O5 layers. Preferably, the first reflective layer 40 is formed by first forming a relatively thick SiO2 layer with a thickness of 100 nm to 500 nm, and then forming a dielectric multilayer film on top of it, consisting of 2 to 6 pairs of Nb2O5 layers with a thickness of 10 nm to 100 nm and SiO2 layers with a thickness of 10 nm to 100 nm. By setting the thickness of each layer and the number of layers stacked in the first reflective layer 40 in this way, good light reflectivity can be achieved. For example, the first reflective layer 40 can be formed by first forming an SiO2 layer with a thickness of 300 nm, and then forming 3 pairs of Nb2O5 layers with a thickness of 52 nm and SiO2 layers with a thickness of 83 nm on top of it. Materials such as titanium oxide (TiO2), zirconium oxide (ZrO2), aluminum oxide (Al2O3), and aluminum nitride (AlN) can be used as the first reflective layer 40. The first reflective layer 40 is formed, for example, by vapor deposition or sputtering.

[0042] <Process for forming the third mask> The manufacturing method for the light-emitting element of this embodiment includes a step of removing the translucent conductive film 15 exposed from the second mask 92, followed by a step of forming a third mask 93 on the translucent conductive film 15 and on the semiconductor structure 10, as shown in Figures 21 to 23. The third mask 93 is also formed on the n-side electrode 31 and the p-side electrode 32. If the first reflective layer 40 is formed, the third mask 93 is formed on the first reflective layer 40. The case in which the first reflective layer 40 is formed will be described below.

[0043] For example, a photoresist can be used for the third mask 93. Through exposure and development processes, a plurality of third masks 93 are formed that are separated from each other in the first direction X and the second direction Y in a plan view. As shown in Figures 21 to 23, the first reflective layer 40 located between adjacent third masks 93 in the first direction X and the second direction Y is exposed from the third mask 93.

[0044] <Process for removing semiconductor structures in areas that do not overlap with the third mask> The manufacturing method for the light-emitting element of the embodiment includes, after the step of forming the third mask 93, the step of removing the semiconductor structure 10 in a region that does not overlap with the third mask 93 in a plan view, as shown in Figures 24 to 26, and forming grooves 80 in the semiconductor structure 10. The grooves 80 extend in a first direction X and a second direction Y, separating the semiconductor structure 10 into a plurality of element portions 100 in the first direction X and the second direction Y. In a plan view, the grooves 80 surround the outer edges of the element portions 100.

[0045] A groove 80 is formed in the semiconductor structure 10 by removing the first reflective layer 40 and the semiconductor structure 10 in the region between adjacent third masks 93 in the first direction X and the second direction Y, so that the n-side layer 11 is exposed. As shown in Figures 25 and 26, the n-side layer 11, the active layer 13, and the p-side layer 12 are exposed on the side surface of the groove 80.

[0046] In the process of forming the groove 80, the first reflective layer 40 and the semiconductor structure 10 are removed, for example, by dry etching. Examples of dry etching methods include the RIE method. The process of forming the groove 80 by the RIE method includes a step of removing the first reflective layer 40 exposed from the third mask 93 by a first etching using a first gas containing fluorine, and a step of removing the semiconductor structure 10 exposed from the third mask 93 by a second etching using a second gas containing chlorine after the first reflective layer 40 has been removed. The first gas includes, for example, CF4 and CHF3. The second gas includes, for example, Cl2 and SiCl4.

[0047] As shown in Figures 25 and 26, the formation of the groove 80 makes it possible to form an element portion 100 in which the first reflective layer 40 is not arranged over substantially the entire surface of the side surface of the active layer 13. Therefore, the efficiency of light extraction from the side surface of the active layer 13 to the outside can be increased. Note that, as shown in Figure 25, the first reflective layer 40 is formed on the side surface of the active layer 13 that is continuous with the n-side exposed portion 11a.

[0048] As shown in Figure 22, the semiconductor structure 10 in the region between adjacent third masks 93 has a first portion 10-1 including an n-side layer 11, an active layer 13, and a p-side layer 12, and a second portion 10-2 consisting only of the n-side layer 11. There is a step between the first portion 10-1 and the second portion 10-2. Therefore, as shown in Figure 25, a step is formed on the bottom surface that defines the groove 80 formed by removing the semiconductor structure 10. In the groove 80, the depth of the second region 80b formed by etching the second portion 10-2 is deeper than the depth of the first region 80a formed by etching the first portion 10-1. The difference in depth between the first region 80a and the second region 80b is, for example, 0.5 μm or more and 5 μm or less.

[0049] For example, the groove 80 does not penetrate the semiconductor structure 10 and does not reach the first substrate 101. However, the groove 80 may be formed to penetrate the semiconductor structure 10 and reach the first substrate 101.

[0050] In this embodiment, the steps of forming a first mask 91 and a second mask 92 for patterning the translucent conductive film 15 are performed before the step of forming the grooves 80. By performing exposure and development treatment on the first mask 91 and the second mask 92 on a wafer with few irregularities before forming the grooves 80, the accuracy of patterning the first mask 91 having a mask opening 91a and the plurality of second masks 92 spaced apart from each other can be improved. As a result, the accuracy of patterning the translucent conductive film 15 can be improved.

[0051] In this embodiment, as shown in Figure 15, in a plan view, the n-side exposed portion 11a extends from an external position to the inside of the translucent conductive film 15 and has an extension portion 11b located between the translucent conductive films 15. The n-side electrode 31 is formed on the extension portion 11b. With this configuration, in a plan view, compared to a configuration where the n-side exposed portion 11a, which extends linearly in the first direction X or second direction Y, faces one outer edge of the translucent conductive film 15 extending in the first direction X or second direction Y, it is easier to reduce the area of ​​the region between the outer edge of the translucent conductive film 15 and the outer edge of the n-side exposed portion 11a (the region without the translucent conductive film 15). As a result, the area of ​​the translucent conductive film 15 can be increased, making it easier to increase the effective light-emitting region.

[0052] Figures 27 and 28 show one element unit 100.

[0053] In the process of removing the semiconductor structure 10 exposed from the third mask 93 to form a groove 80, it is preferable to remove the semiconductor structure 10 such that, in a plan view, the shortest distance d1 between the outer edge 11o of the n-side exposed portion 11a and the outer edge 15b of the translucent conductive film 15 facing the outer edge 11o of the n-side exposed portion 11a is greater than the shortest distance d2 between the groove 80 and the outer edge 15c of the translucent conductive film 15 facing the groove 80. This makes it easier to secure a wide light-emitting area while making it less likely for electrostatic discharge breakdown of the light-emitting element to occur. For example, the shortest distance d1 can be 1 μm or more, and the shortest distance d2 can be 1 μm or less. For example, the difference between the shortest distance d1 and the shortest distance d2 is 0.1 μm or more and 1 μm or less.

[0054] The manufacturing method for the light-emitting element of this embodiment may further include the steps shown in Figure 29 and subsequent figures, after separating the element into a plurality of element sections 100 by the groove 80. In Figure 29 and subsequent figures, one element section 100 is shown.

[0055] As shown in Figures 29 and 30, a second reflective layer 50 is formed on the first reflective layer 40. The formation of the second reflective layer 50 reflects the light from the active layer 13 that has passed through the first reflective layer 40, thereby improving the light extraction efficiency. The second reflective layer 50 is formed, for example, by sputtering. The second reflective layer 50 is, for example, a metal layer. The second reflective layer 50 includes, for example, an Al layer, a Ti layer, or a stacked structure thereof.

[0056] Next, as shown in Figure 31, a first opening 41 that exposes a portion of the n-side electrode 31 and a second opening 42 that exposes a portion of the p-side electrode 32 are formed in the first reflective layer 40. The first opening 41 and the second opening 42 are formed simultaneously, for example, by the RIE method.

[0057] Next, as shown in Figure 32, an insulating layer 61 is formed to cover the first reflective layer 40 and the second reflective layer 50. The insulating layer 61 covers the side surface of the first reflective layer 40 defining the first opening 41, the side surface of the first reflective layer 40 defining the second opening 42, and the side surface of the semiconductor structure 10 defining the groove 80. The insulating layer 61 is, for example, a silicon oxide layer. The side surface of the semiconductor structure 10 is covered by the insulating layer 61. The insulating layer 61 is formed, for example, by sputtering or CVD.

[0058] Next, as shown in Figures 33 and 34, a first conductive member 71 is formed in the first opening 41, and a second conductive member 72 is formed in the second opening 42. The first conductive member 71 is in contact with the n-side electrode 31. The second conductive member 72 is in contact with the p-side electrode 32. The first conductive member 71 is also formed on the insulating layer 61 around the first opening 41. The second conductive member 72 is also formed on the insulating layer 61 around the second opening 42. On the insulating layer 61, the first conductive member 71 and the second conductive member 72 are spaced apart from each other. The thickness of the first conductive member 71 and the second conductive member 72 is, for example, 0.1 μm or more and 5 μm or less. In plan view, the shape of the first conductive member 71 and the second conductive member 72 is, for example, approximately rectangular, with the length of the long side being 10 μm or more and 100 μm or less. For example, the first conductive member 71 is the cathode electrode, and the second conductive member 72 is the anode electrode.

[0059] For example, the first conductive member 71 and the second conductive member 72 are formed simultaneously by a sputtering method. The first conductive member 71 and the second conductive member 72 include, for example, a Ti layer, a Rh layer, an Au layer, or a laminated structure of any two of these.

[0060] When a dielectric multilayer film is used as the first reflective layer 40, for example, by using an Nb2O5 layer, a dielectric multilayer film having high reflectivity to light emitted by the active layer 13 can be formed. However, the Nb2O5 layer may generate leakage current, which may worsen the reliability of the light-emitting element. In this embodiment, even when the Nb2O5 layer is included as a film in the dielectric multilayer film, an insulating layer 61 is formed between the first reflective layer 40 and the first conductive member 71, and between the first reflective layer 40 and the second conductive member 72, so that a short circuit between the first conductive member 71 and the second conductive member 72 through the first reflective layer 40 can be prevented. Therefore, the light extraction efficiency can be improved without worsening the reliability of the light-emitting element.

[0061] Furthermore, even if the second reflective layer 50 is a metal layer, an insulating layer 61 is formed between the second reflective layer 50 and the first conductive member 71, and between the second reflective layer 50 and the second conductive member 72. This prevents short circuits between the first conductive member 71 and the second conductive member 72 through the second reflective layer 50. As a result, the light extraction efficiency can be improved without degrading the reliability of the light-emitting element.

[0062] The process shown in Figures 35 to 41 is then carried out. In Figures 35 to 41, the upper and lower positions of the element section 100 are shown in reverse compared to the figures up to 34.

[0063] In the process shown in Figure 35, the semiconductor structure 10 and the second substrate 102 are joined via a resin member 70. The resin member 70 covers the first conductive member 71, the second conductive member 72, and the insulating layer 61, and is also formed within the groove 80. The resin member 70 is mainly composed of, for example, epoxy resin, acrylic resin, or polyimide resin. The second substrate 102 can be a substrate such as sapphire, spinel, SiC, ZnS, ZnO, GaAs, or Si, similar to the first substrate 101.

[0064] After bonding the semiconductor structure 10 and the second substrate 102, the first substrate 101 is removed to expose the first surface 10a of the semiconductor structure 10 that was in contact with the first substrate 101, as shown in Figure 36. The first substrate 101 is removed by methods such as the Laser Lift Off (LLO) method, grinding, polishing, or etching.

[0065] The first surface 10a contains, for example, GaN, and the laser light used for LLO is, for example, deep ultraviolet light. When the laser light is irradiated, the Ga of GaN sublimes, causing the first substrate 101 to peel off from the first surface 10a. At this time, in the process of forming the groove 80 shown in Figures 25 and 26, a part of the semiconductor structure 10 is left between the bottom surface of the groove 80 and the first substrate 101, so that the first surface 10a is present over the entire surface of the first substrate 101 during LLO. This makes it easier to peel off the first substrate 101 by the LLO method.

[0066] Next, the semiconductor structure 10 is removed from the exposed first surface 10a. For example, CMP (Chemical Mechanical Polishing) is used to remove the semiconductor structure 10. By performing this step, for example, the first surface 10a will have a maximum height difference of about 1 nm to 30 nm. As shown in Figure 37, the semiconductor structure 10 is removed from the first surface 10a so that the semiconductor structure 10 located in the groove 80 is removed. By removing the semiconductor structure 10 located in the groove 80, the element portion 100 is separated into individual pieces.

[0067] Next, as shown in Figure 38, a first protective film 62 is formed to cover the outer periphery of the first surface 10a. The first protective film 62 also covers the end of the insulating layer 61 covering the side surface of the n-side layer 11 on the first surface 10a side. The first protective film 62 is transparent to light emitted by the active layer 13. The first protective film 62 is, for example, a silicon oxide film. After the first protective film 62 is formed over the entire surface of the first surface 10a, for example by sputtering, the first protective film 62 other than the outer periphery of the first surface 10a is removed by RIE using a resist mask (not shown). Here, "outer periphery of the first surface 10a" means, for example, the area within 10 μm from the outer edge of the first surface 10a in a plan view.

[0068] After forming the first protective film 62, as shown in Figure 39, the first surface 10a exposed from the first protective film 62 is roughened to form a rough surface with irregularities on the first surface 10a. The first surface 10a is the main light extraction surface of the light-emitting element, and by forming a rough surface on the first surface 10a, the light extraction efficiency of the light-emitting element can be improved. By setting the maximum height difference of the irregularities on the first surface 10a to, for example, 1 μm to 3 μm, the light extraction efficiency of the light-emitting element can be improved. For example, the first surface 10a can be roughened by the RIE method using a gas containing chlorine or by wet etching using an alkaline solution such as TMAH (Tetramethylammonium hydroxide).

[0069] If the entire surface of the first surface 10a is roughened, chipping of the n-side layer 11 is likely to occur at the outer periphery of the first surface 10a. In this embodiment, since the outer periphery of the first surface 10a that continues to the side surface of the n-side layer 11 is covered with the first protective film 62, it is possible to form an area that is not roughened at the outer periphery of the first surface 10a. As a result, the occurrence of chipping of the n-side layer 11 at the outer periphery of the first surface 10a can be reduced. It is preferable to roughen the first surface 10a while leaving the resist mask used when removing the first protective film 62 other than the outer periphery of the first surface 10a on the first protective film 62 at the outer periphery of the first surface 10a. As a result, it is possible to form an area that is not roughened at the outer periphery of the n-side layer 11 on the first surface 10a.

[0070] Next, as shown in Figure 40, a second protective film 63 is formed on the roughened first surface 10a. The second protective film 63 is also formed on the first protective film 62. The second protective film 63 is transparent to light emitted by the active layer 13. The second protective film 63 is, for example, a silicon oxide film. The second protective film 63 is formed, for example, by sputtering. The thickness of the second protective film 63 is, for example, 0.1 μm to 3 μm. The insulating layer 61 covering the side surface of the n-side layer 11 is also transparent to light emitted by the active layer 13.

[0071] Next, the first protective film 62, the second protective film 63, and a portion of the resin member 70 located between the individualized element portions 100 are removed by etching. As a result, as shown in Figure 41, a plurality of light-emitting elements 1 are obtained on the second substrate 102, separated from each other by space. Figure 42 shows an example of a bottom view of the light-emitting element 1 shown in Figure 41.

[0072] The light-emitting element 1 is supported on the second substrate 102 via a resin member 70, with the side opposite to the first surface 10a facing the second substrate 102. For example, by irradiating the second substrate 102 with laser light, a portion of the resin member 70 can be removed, and the light-emitting element 1 can be removed from the second substrate 102. After being removed from the second substrate 102, the side of the light-emitting element 1 on which the second protective film 63 is formed is joined to another support substrate, for example, an adhesive one. The light-emitting element 1 may be removed from the second substrate 102 after being joined to another support substrate. Subsequently, the remaining resin member 70 on the light-emitting element 1 is removed to expose the first conductive member 71 and the second conductive member 72. The removal of the remaining resin member 70 on the light-emitting element 1 can be performed, for example, by the RIE method. The exposed first conductive member 71 and the second conductive member 72 function as external connection terminals that are joined to a mounting substrate. The light-emitting element 1 is, for example, a light-emitting diode (LED).

[0073] The light emitted by the active layer 13 is mainly extracted to the outside of the light-emitting element 1 from the first surface 10a. In addition, the light emitted by the active layer 13 is also extracted to the outside of the light-emitting element 1 from the side surface 11c of the n-side layer 11. According to this embodiment, by arranging the first reflective layer 40 on the surface opposite to the first surface 10a and not arranging a reflective layer on the side surface 11c, the efficiency of light extraction from the light-emitting element 1 to the outside can be increased. Note that as the planar size of the light-emitting element 1 decreases, the proportion of light extracted from the side surface 11c increases. Therefore, the structure without a reflective layer on the side surface 11c is particularly effective when the length of one side of the first surface 10a in plan view is relatively small. For example, it is particularly effective when the size of one side of the first surface 10a in plan view is 100 μm or less, and even more effective when the size of one side of the first surface 10a in plan view is 60 μm or less.

[0074] By forming a dielectric multilayer film with a lower light absorption rate than a metal layer as the first reflective layer 40, the reflectivity can be increased compared to the case where a metal layer is used as the first reflective layer 40. Furthermore, by forming a second reflective layer 50 on the side opposite to the first surface 10a, the reflectivity can be increased even further.

[0075] Embodiments of the present invention include the following methods for manufacturing light-emitting elements.

[0076] [Section 1] A step of preparing a wafer having a semiconductor structure having an n-side layer, an active layer disposed on the n-side layer, a p-side layer disposed on the active layer, and a translucent conductive film disposed on the p-side layer. The process involves forming a first mask on the light-transmitting conductive film, After the step of forming the first mask, the translucent conductive film exposed from the first mask is removed, and an opening is formed in the translucent conductive film to expose the semiconductor structure from the translucent conductive film, The process involves removing the translucent conductive film exposed from the first mask, then removing the semiconductor structure exposed from the first mask, and forming an n-side exposed portion in which a part of the n-side layer is exposed from the p-side layer and the active layer. After the step of forming the n-side exposed portion, the first mask is removed, The process involves removing the first mask, and then forming a second mask on the translucent conductive film at a position away from the outer edge that defines the opening of the translucent conductive film in a plan view. After the step of forming the second mask, the process involves removing the translucent conductive film exposed from the second mask and exposing the p-side layer from the translucent conductive film, The process of forming the n-side electrode in the n-side exposed portion, The process involves removing the translucent conductive film exposed from the second mask, followed by forming a third mask on the translucent conductive film and the semiconductor structure. After the step of forming the third mask, the semiconductor structure in a region that does not overlap with the third mask in a plan view is removed, and grooves are formed in the semiconductor structure to separate the semiconductor structure into multiple element parts. A method for manufacturing a light-emitting element. [Section 2] The method for manufacturing a light-emitting element according to item 1, wherein, in the step of removing the semiconductor structure exposed from the third mask, the semiconductor structure is removed such that the shortest distance between the outer edge of the translucent conductive film and the outer edge of the n-side exposed portion in a plan view is greater than the shortest distance between the outer edge of the translucent conductive film and the groove in a plan view. [Section 3] A method for manufacturing a light-emitting element according to item 1 or 2, wherein in the step of removing the translucent conductive film exposed from the first mask, the translucent conductive film is removed by wet etching. [Section 4] The method for manufacturing a light-emitting element according to item 3, wherein in the step of removing the translucent conductive film exposed from the second mask, the translucent conductive film is removed by wet etching. [Section 5] In the step of forming the first mask, the first mask having a plurality of openings is formed, In the process of forming the second mask, a plurality of the second masks that are separated from each other are formed. The method for manufacturing a light-emitting element according to item 4, wherein the wet etching time for removing the translucent conductive film exposed from the first mask is longer than the wet etching time for removing the translucent conductive film exposed from the second mask. [Section 6] A method for manufacturing a light-emitting element according to any one of the above items 1 to 5, wherein in the step of removing the semiconductor structure exposed from the first mask and forming the n-side exposed portion, the semiconductor structure is removed by dry etching. [Section 7] In a plan view, the n-side exposed portion extends toward the inside of the translucent conductive film and has an extension portion located between the translucent conductive films. The n-side electrode is formed in the extension portion. A method for manufacturing a light-emitting element according to any one of the above items 1 to 6.

[0077] The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. All forms that a person skilled in the art can implement by appropriately modifying the design based on the above-described embodiments of the present invention also fall within the scope of the present invention, insofar as they encompass the gist of the present invention. Furthermore, within the scope of the idea of ​​the present invention, a person skilled in the art can conceive of various modifications and alterations, and these modifications and alterations also fall within the scope of the present invention. [Explanation of Symbols]

[0078] 1...Light-emitting element, 10...Semiconductor structure, 11...n-side layer, 11a...n-side exposed portion, 12...p-side layer, 13...Active layer, 15...Transparent conductive film, 15a...Opening, 15o...Outer edge, 31...n-side electrode, 32...p-side electrode, 40...First reflective layer, 50...Second reflective layer, 61...Insulating layer, 62...First protective film, 63...Second protective film, 70...Resin component, 71...First conductive component, 72...Second conductive component, 80...Groove, 91...First mask, 91a...Mask opening, 92...Second mask, 93...Third mask, 100...Element portion, 101...First substrate, 102...Second substrate, W...Wafer

Claims

1. A step of preparing a wafer having a semiconductor structure having an n-side layer, an active layer disposed on the n-side layer, a p-side layer disposed on the active layer, and a translucent conductive film disposed on the p-side layer, The process involves forming a first mask on the light-transmitting conductive film, After the step of forming the first mask, the translucent conductive film exposed from the first mask is removed, and an opening is formed in the translucent conductive film to expose the semiconductor structure from the translucent conductive film, The process involves removing the translucent conductive film exposed from the first mask, then removing the semiconductor structure exposed from the first mask, and forming an n-side exposed portion in which a part of the n-side layer is exposed from the p-side layer and the active layer. After the step of forming the n-side exposed portion, the first mask is removed, The process involves removing the first mask, and then forming a second mask on the translucent conductive film at a position away from the outer edge that defines the opening of the translucent conductive film in a plan view. After the step of forming the second mask, the translucent conductive film exposed from the second mask is removed, and the p-side layer is exposed from the translucent conductive film. The process of forming the n-side electrode in the n-side exposed portion, The process involves removing the translucent conductive film exposed from the second mask, followed by forming a third mask on the translucent conductive film and the semiconductor structure. After the step of forming the third mask, the semiconductor structure in a region that does not overlap with the third mask in a plan view is removed, and grooves are formed in the semiconductor structure to separate the semiconductor structure into multiple element parts. A method for manufacturing a light-emitting element.

2. The method for manufacturing a light-emitting element according to claim 1, wherein, in the step of removing the semiconductor structure exposed from the third mask, the semiconductor structure is removed such that the shortest distance between the outer edge of the translucent conductive film and the outer edge of the n-side exposed portion in a plan view is greater than the shortest distance between the outer edge of the translucent conductive film and the groove in a plan view.

3. The method for manufacturing a light-emitting element according to claim 1 or 2, wherein in the step of removing the translucent conductive film exposed from the first mask, the translucent conductive film is removed by wet etching.

4. The method for manufacturing a light-emitting element according to claim 3, wherein in the step of removing the translucent conductive film exposed from the second mask, the translucent conductive film is removed by wet etching.

5. In the step of forming the first mask, the first mask having a plurality of openings is formed, In the process of forming the second mask, a plurality of the second masks that are separated from each other are formed, The method for manufacturing a light-emitting element according to claim 4, wherein the wet etching time for removing the translucent conductive film exposed from the first mask is longer than the wet etching time for removing the translucent conductive film exposed from the second mask.

6. A method for manufacturing an element-emitting element according to claim 1 or 2, wherein in the step of removing the semiconductor structure exposed from the first mask and forming the n-side exposed portion, the semiconductor structure is removed by dry etching.

7. In a plan view, the n-side exposed portion extends toward the inside of the translucent conductive film and has an extension portion located between the translucent conductive films. The method for manufacturing a light-emitting element according to claim 1 or 2, wherein the n-side electrode is formed in the extension portion.

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