Semiconductor light-emitting device

Abstract

To improve efficiency and reliability of taking out light of a semiconductor light-emitting device.SOLUTION: A semiconductor light-emitting device 10 includes: a package substrate 14; a semiconductor light-emitting element 12 flip-chip-joined to a surface of the package substrate 14; a frame body 16 provided around the semiconductor light-emitting element 12 on the package substrate 14; and a sealing member 18 covering the semiconductor light-emitting element 12 on the package substrate 14 and an upper surface 16a of the frame body 16 and having light transmissivity at the light-emitting wavelength of the semiconductor light-emitting element 12. A height h1 of the upper surface 16a of the frame body 16 is smaller than a height ha of an upper surface 12a of the semiconductor light-emitting element 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a semiconductor light emitting device. [Background technology]

[0002] There is known a semiconductor light emitting device in which a semiconductor light emitting element bonded onto a package substrate is sealed with resin. For example, a technology has been proposed to improve the light extraction efficiency by forming the sealing resin into a dome shape that is convex upward (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-59754 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the sealing member is formed in a dome shape, it is necessary to increase the thickness of the sealing member located above the semiconductor light emitting element. If the thickness of the sealing member is increased, the distortion caused by the difference in material between the sealing member and the package substrate increases, and the sealing member becomes more likely to peel off or crack.

[0005] The present invention has been made in view of these problems, and has an object to provide a technique for improving the light extraction efficiency and reliability of a semiconductor light emitting device. [Means for solving the problem]

[0006] A semiconductor light emitting device according to an embodiment of the present invention includes a package substrate, a semiconductor light emitting element flip-chip bonded onto the package substrate, a frame provided around the semiconductor light emitting element on the package substrate, and a sealing member that covers the semiconductor light emitting element on the package substrate, covers an upper surface of the frame, and is translucent at the emission wavelength of the semiconductor light emitting element, wherein the height of the upper surface of the frame is smaller than the height of the upper surface of the semiconductor light emitting element.

[0007] According to the present invention, it is possible to improve the light extraction efficiency and reliability of a semiconductor light emitting device. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view illustrating a schematic configuration of a semiconductor light-emitting device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. In the description, the same elements are given the same reference numerals, and duplicated descriptions will be omitted as appropriate. In addition, in order to facilitate understanding of the description, the dimensional ratios of the components in each drawing do not necessarily match the dimensional ratios of the actual light-emitting element.

[0010] 1 is a cross-sectional view showing a schematic configuration of a semiconductor light emitting device 10 according to an embodiment. The semiconductor light emitting device 10 includes a semiconductor light emitting element 12, a package substrate 14, a frame 16, and a sealing member 18.

[0011] The semiconductor light emitting element 12 is a semiconductor light emitting element configured to emit ultraviolet light with a central wavelength λ of about 360 nm or less. In order to output ultraviolet light with such a wavelength, an aluminum gallium nitride (AlGaN)-based semiconductor material with a band gap of about 3.4 eV or more is used. In this embodiment, in particular, a DUV-LED (Deep UltraViolet-Light Emitting Diode) chip that emits deep ultraviolet light with a central wavelength λ of about 240 nm to 320 nm is shown.

[0012] The semiconductor light-emitting element 12 includes a translucent substrate 20, a semiconductor layer 22, an anode electrode 24, a cathode electrode 26, and a protective layer 28.

[0013] The translucent substrate 20 is made of a material that is translucent to the ultraviolet light emitted by the semiconductor light-emitting element 12. The light emitted by the semiconductor layer 22 is output from the translucent substrate 20 to the outside of the semiconductor light-emitting element 12. The translucent substrate 20 is composed of, for example, sapphire (Al2O3). The translucent substrate 20 has an upper surface 20a and a lower surface 20b. The upper surface 20a and the lower surface 20b are, for example, rectangular. The sizes of the upper surface 20a and the lower surface 20b are not particularly limited, but are, for example, 1 mm square. The thickness t from the upper surface 20a to the lower surface 20b of the translucent substrate 20 is, for example, 100 μm or more, 200 μm or more, or 300 μm or more, and is, for example, 1000 μm or less, 700 μm or less, or 500 μm or less.

[0014] The semiconductor layer 22 is provided under the translucent substrate 20 and is provided on the lower surface 20b of the translucent substrate 20. The semiconductor layer 22 includes, for example, an n-type semiconductor layer, an active layer, and a p-type semiconductor layer. The semiconductor layer 22 is composed of an AlGaN-based semiconductor material. The AlGaN-based semiconductor material can be represented by the composition of In 1-x-y Al x Ga y N (0 < x + y ≤ 1, 0 < x < 1, 0 < y < 1). The semiconductor layer 22 is covered by the protective layer 28.

[0015] The anode electrode 24 includes a first contact electrode 24a and a first pad electrode 24b. The first contact electrode 24a is an internal electrode that contacts the semiconductor layer 22 and contacts the p-type semiconductor layer included in the semiconductor layer 22. The first contact electrode 24a is composed of, for example, a metal layer such as Rh. The first contact electrode 24a is covered by the protective layer 28. The first pad electrode 24b is an external electrode that is exposed outside the protective layer 28 and is electrically connected to the first contact electrode 24a through an opening provided in the protective layer 28. The first pad electrode 24b is composed of a metal layer such as Ni / Au.

[0016] The cathode electrode 26 includes a second contact electrode 26a and a second pad electrode 26b. The second contact electrode 26a is an internal electrode in contact with the semiconductor layer 22, and is in contact with an n-type semiconductor layer included in the semiconductor layer 22. The second contact electrode 26a is made of a metal layer such as Ti / Al. The second contact electrode 26a is covered by a protective layer 28. The second pad electrode 26b is an external electrode exposed to the outside of the protective layer 28, and is electrically connected to the second contact electrode 26a through an opening provided in the protective layer 28. The second pad electrode 26b is made of a metal layer such as Ni / Au.

[0017] The protective layer 28 covers the semiconductor layer 22, the first contact electrode 24a, and the second contact electrode 26a. The protective layer 28 is made of a dielectric material such as an oxide or a nitride, for example, silicon oxide (SiO2), aluminum oxide (Al2O3), silicon nitride (SiN), etc. The protective layer 28 may be made of a laminate of multiple protective layers made of different materials.

[0018] The package substrate 14 has a flat plate shape and has a bonding surface 14a and a back surface 14b. The package substrate 14 includes a first bonding electrode 30 and a second bonding electrode 32 provided on the bonding surface 14a. The package substrate 14 includes a first mounting electrode 34 and a second mounting electrode 36 provided on the back surface 14b. The first bonding electrode 30 is electrically connected to the first mounting electrode 34 inside the package substrate 14. The second bonding electrode 32 is electrically connected to the second mounting electrode 36 inside the package substrate 14. The package substrate 14 is made of, for example, an inorganic material, such as a ceramic material such as alumina (Al2O3), aluminum nitride (AlN), silicon nitride (SiN), or silicon carbide (SiC).

[0019] The semiconductor light emitting element 12 is flip-chip bonded onto the package substrate 14. The semiconductor light emitting element 12 is bonded to a first bonding electrode 30 and a second bonding electrode 32. The semiconductor light emitting element 12 is bonded to the package substrate 14 via a first bonding portion 38 and a second bonding portion 40. The first bonding portion 38 is provided between the anode electrode 24 (first pad electrode 24b) and the first bonding electrode 30, and electrically connects the anode electrode 24 and the first bonding electrode 30. The second bonding portion 40 is provided between the cathode electrode 26 (second pad electrode 26b) and the second bonding electrode 32, and electrically connects the cathode electrode 26 and the second bonding electrode 32.

[0020] The first bonding portion 38 and the second bonding portion 40 are, for example, stud bumps. The first bonding portion 38 and the second bonding portion 40 are formed, for example, by melting the tip of a metal wire such as Au to form a ball shape, and pressing the ball against the first bonding electrode 30 and the second bonding electrode 32, respectively. The first bonding portion 38 and the second bonding portion 40 formed on the first bonding electrode 30 and the second bonding electrode 32 are bonded to the anode electrode 24 (first pad electrode 24b) and the cathode electrode 26 (second pad electrode 26b), respectively, by, for example, ultrasonic bonding.

[0021] In a state in which the semiconductor light emitting element 12 is bonded to the package substrate 14, the height hb from the package substrate 14 (bonding surface 14a) to the lower surface 20b of the light-transmitting substrate 20 is, for example, smaller than the thickness t of the light-transmitting substrate 20, for example, smaller than half the thickness t / 2 of the light-transmitting substrate 20. The height hb from the package substrate 14 to the lower surface 20b of the light-transmitting substrate 20 is, for example, 200 μm or less, 100 μm or less, 50 μm or less, or 30 μm or less. The height hb from the package substrate 14 to the lower surface 20b of the light-transmitting substrate 20 is, for example, 10 μm or more, 15 μm or more, 20 μm or more, or 25 μm or more.

[0022] When the semiconductor light emitting element 12 is bonded to the package substrate 14, the height ha from the package substrate 14 (bonding surface 14a) to the upper surface 12a of the semiconductor light emitting element 12 (upper surface 20a of the light-transmitting substrate 20) is, for example, 100 μm or more, 200 μm or more, 300 μm or more, or 400 μm or more. The height ha from the package substrate 14 to the upper surface 12a of the semiconductor light emitting element 12 is, for example, 1000 μm or less, 700 μm or less, 600 μm or less, or 500 μm or less.

[0023] The frame body 16 is provided around the semiconductor light emitting element 12 on the package substrate 14. The frame body 16 is provided, for example, along the outer periphery of the package substrate 14, over the entire periphery of the package substrate 14. The frame body 16 may be provided away from the outer periphery of the package substrate 14, or may be provided at a position shifted inward from the outer periphery of the package substrate 14. The shape of the frame body 16 when the upper surface 16a of the frame body 16 is viewed is rectangular, for example, square. The shape of the frame body 16 when the upper surface 16a of the frame body 16 is viewed may be circular. The frame body 16 is formed, for example, of the same material as the package substrate 14, and is molded integrally with the package substrate 14. The frame body 16 may be formed of a material different from the package substrate 14. The frame body 16 may be molded separately from the package substrate 14, or may be bonded to the bonding surface 14a of the package substrate 14 by any bonding material.

[0024] The frame body 16 has an upper surface 16a. The upper surface 16a of the frame body 16 is, for example, a flat surface. The height h1 of the upper surface 16a of the frame body 16 is smaller than the height ha of the upper surface 12a of the semiconductor light emitting element 12 (the upper surface 20a of the light-transmitting substrate 20). The height h1 from the package substrate 14 to the upper surface 16a of the frame body 16 is, for example, 80% or less, 70% or less, 60% or less, or 50% or less of the height ha from the package substrate 14 to the upper surface 12a of the semiconductor light emitting element 12. The height h1 of the upper surface 16a of the frame body 16 is, for example, smaller than the height (middle height hc) at the middle position 20c where the thickness t of the light-transmitting substrate 20 is half (t / 2). The height h1 of the upper surface 16a of the frame body 16 is, for example, larger than the height hb of the lower surface 20b of the light-transmitting substrate 20. The height h1 from the package substrate 14 to the upper surface 16a of the frame 16 is, for example, 20% or more, 30% or more, 40% or more, or 50% or more of the height ha from the package substrate 14 to the upper surface 12a of the semiconductor light emitting element 12.

[0025] The height h1 of the upper surface 16a of the frame 16 is, for example, 50 μm or more, 100 μm or more, 150 μm or more, or 200 μm or more. The height h1 of the upper surface 16a of the frame 16 is, for example, 700 μm or less, 500 μm or less, 400 μm or less, or 300 μm or less. The difference Δh (= ha-h1) between the height h1 of the upper surface 16a of the frame 16 and the height ha of the upper surface 12a of the semiconductor light emitting element 12 is, for example, 50 μm or more, 100 μm or more, or 200 μm or more, and, for example, 500 μm or less, 400 μm or less, or 300 μm or less.

[0026] The sealing member 18 covers the semiconductor light emitting element 12 on the package substrate 14. The sealing member 18 fills, for example, an area inside the frame body 16. The sealing member 18 covers the upper surface 16a of the frame body 16. The sealing member 18 is made of a material having translucency at the emission wavelength of the semiconductor light emitting element 12. The sealing member 18 has an internal transmittance of 50% or more at the peak emission wavelength of the semiconductor light emitting element 12, and preferably 70% or more, 80% or more, or 90% or more. The sealing member 18 is made of a material having a lower refractive index than the translucent substrate 20. The sealing member 18 is made of, for example, a silicone resin or a fluororesin. The sealing member 18 may be made of an inorganic material such as quartz or a glass material instead of a resin. The sealing member 18 is configured not to contain a phosphor, for example.

[0027] The sealing member 18 has, for example, a lens shape or a dome shape that is convex upward. The top 42 of the sealing member 18 is located at the top of the semiconductor light emitting element 12 that is bonded to, for example, the package substrate 14. The sealing member 18 is formed so as to cover the entire top surface 12a of the semiconductor light emitting element 12 and to cover the corners 20d that form the outer periphery of the top surface 20a of the light-transmitting substrate 20. The height h2 from the top surface 12a of the semiconductor light emitting element 12 to the top 42 of the sealing member 18 is, for example, 50 μm or more, 100 μm or more, or 200 μm or more. The height h2 from the top surface 12a of the semiconductor light emitting element 12 to the top 42 of the sealing member 18 is, for example, greater than half the thickness t / 2 of the light-transmitting substrate 20. The height h2 from the top surface 12a of the semiconductor light emitting element 12 to the top 42 of the sealing member 18 is, for example, 500 μm or less, 400 μm or less, or 300 μm or less. The height h2 from the upper surface 12a of the semiconductor light emitting element 12 to the top 42 of the sealing member 18 is smaller than, for example, the height ha from the package substrate 14 to the upper surface 12a of the semiconductor light emitting element 12, and is smaller than the thickness t of the light-transmitting substrate 20. By reducing the height h2 of the sealing member 18 located above the semiconductor light emitting element 12, peeling and cracking of the sealing member 18 can be suppressed.

[0028] According to this embodiment, by making the height h1 of the upper surface 16a of the frame 16 smaller than the height ha of the upper surface 12a of the semiconductor light emitting element 12, the height h2 of the sealing member 18 covering the upper surface 12a of the semiconductor light emitting element 12 can be reduced. In other words, by lowering the height h1 of the upper surface 16a of the frame 16, the sealing member 18 covering the semiconductor light emitting element 12 can be made dome-shaped using a smaller amount of the sealing member 18. As a result, peeling or cracking of the sealing member 18 can be suppressed, and the reliability of the semiconductor light emitting device 10 can be improved.

[0029] According to this embodiment, since the sealing member 18 is provided so as to cover the upper surface 16a of the frame body 16, the curvature of the upper surface of the sealing member 18 can be made gentler than when the sealing member 18 is not provided on the upper surface 16a of the frame body 16. This makes it possible to reduce the height h2 of the sealing member 18 covering the upper surface 12a of the semiconductor light emitting element 12, and the sealing member 18 covering the semiconductor light emitting element 12 can be made dome-shaped using a smaller amount of the sealing member 18. As a result, peeling or cracking of the sealing member 18 can be suppressed, and the reliability of the semiconductor light emitting device 10 can be improved.

[0030] According to this embodiment, since the sealing member 18 is provided so as to cover the upper surface 16a of the frame body 16, even if the thickness t of the light-transmitting substrate 20 is large and the height ha of the semiconductor light-emitting element 12 is large, it is easy to cover the entire semiconductor light-emitting element 12 with the sealing member 18. As a result, the light extraction efficiency from the light-transmitting substrate 20 can be improved, and the light output of the semiconductor light-emitting device 10 can be improved.

[0031] The present invention has been described above based on the embodiments. It will be understood by those skilled in the art that the present invention is not limited to the above-mentioned embodiments, that various design changes are possible, that various modifications are possible, and that such modifications are also within the scope of the present invention.

[0032] Several aspects of the present invention will now be described.

[0033] A first aspect of the present invention is a semiconductor light emitting device including a package substrate, a semiconductor light emitting element flip-chip bonded onto the package substrate, a frame body provided around the semiconductor light emitting element on the package substrate, and a sealing member covering the semiconductor light emitting element on the package substrate, covering the upper surface of the frame body, and having translucency at the emission wavelength of the semiconductor light emitting element, the height of the upper surface of the frame body being smaller than the height of the upper surface of the semiconductor light emitting element. According to the first aspect, by providing a translucent sealing member covering the semiconductor light emitting element, the light extraction efficiency of the semiconductor light emitting device can be improved. In addition, by reducing the height of the upper surface of the frame body, the height of the sealing member covering the upper surface of the semiconductor light emitting element can be reduced. Since the sealing member is also provided on the upper surface of the frame body, the curvature of the upper surface of the sealing member can be made gentle, and the height of the sealing member covering the upper surface of the semiconductor light emitting element can be reduced. By reducing the height of the sealing member covering the upper surface of the semiconductor light emitting element, peeling and cracking of the sealing member can be suppressed, and the reliability of the semiconductor light emitting device can be improved.

[0034] A second aspect of the present invention is the semiconductor light emitting device according to the first aspect, in which the height from the package substrate to the upper surface of the frame is 20% or more and 80% or less of the height from the package substrate to the upper surface of the semiconductor light emitting element. According to the second aspect, by making the height of the upper surface of the frame 20% or more of the height of the semiconductor light emitting element, the curvature of the upper surface of the sealing member can be made gentle, and the height of the sealing member covering the upper surface of the semiconductor light emitting element can be reduced. Furthermore, by making the height of the upper surface of the frame 80% or less of the height of the semiconductor light emitting element, the height of the sealing member covering the upper surface of the semiconductor light emitting element can be reduced. By reducing the height of the sealing member covering the upper surface of the semiconductor light emitting element, peeling or cracking of the sealing member can be suppressed, and the reliability of the semiconductor light emitting device can be improved.

[0035] A third aspect of the present invention is the semiconductor light emitting device according to the first or second aspect, wherein a height from the top surface of the semiconductor light emitting element to a top of the sealing member is smaller than a height from the package substrate to the top surface of the semiconductor light emitting element. According to the third aspect, by reducing the height of the sealing member covering the top surface of the semiconductor light emitting element, peeling or cracking of the sealing member can be suppressed, and the reliability of the semiconductor light emitting device can be improved.

[0036] A fourth aspect of the present invention is the semiconductor light emitting device according to any one of the first to third aspects, wherein the semiconductor light emitting element comprises an anode electrode and a cathode electrode bonded to the package substrate, a semiconductor layer on the anode electrode and the cathode electrode, and a light-transmitting substrate on the semiconductor layer, and the height of the upper surface of the frame is greater than the height of the lower surface of the light-transmitting substrate. According to the fourth aspect, by making the height of the upper surface of the frame greater than the height of the lower surface of the light-transmitting substrate, the height of the sealing member covering the upper surface of the semiconductor light emitting element can be more suitably reduced, and the reliability of the semiconductor light emitting device can be improved.

[0037] A fifth aspect of the present invention is the semiconductor light emitting device according to the fourth aspect, wherein the height of the upper surface of the frame is smaller than a mid-height at which the thickness of the light-transmitting substrate is half. According to the fifth aspect, by making the height of the upper surface of the frame smaller than the mid-height of the light-transmitting substrate, the height of the sealing member covering the upper surface of the semiconductor light emitting element can be more suitably reduced, and the reliability of the semiconductor light emitting device can be improved.

[0038] A sixth aspect of the present invention is the semiconductor light emitting device according to the fourth or fifth aspect, wherein a height from the upper surface of the semiconductor light emitting element to a top of the sealing member is smaller than a thickness of the light-transmitting substrate. According to the sixth aspect, by making the height of the sealing member covering the upper surface of the semiconductor light emitting element smaller than the thickness of the light-transmitting substrate, peeling or cracking of the sealing member can be suppressed, and the reliability of the semiconductor light emitting device can be improved.

[0039] A seventh aspect of the present invention is the semiconductor light emitting device according to any one of the fourth to sixth aspects, in which the thickness of the light transmissive substrate is 300 μm or more and 500 μm or less. According to the seventh aspect, even if the thickness of the light transmissive substrate is large, the height of the sealing member covering the upper surface of the semiconductor light emitting element can be reduced by providing a frame body with a small height. This makes it possible to suppress peeling or cracking of the sealing member and improve the reliability of the semiconductor light emitting device. [Explanation of symbols]

[0040] 10...semiconductor light emitting device, 12...semiconductor light emitting element, 12a...upper surface, 14...package substrate, 16...frame, 16a...upper surface, 18...sealing member, 20...light-transmitting substrate, 20a...upper surface, 20b...lower surface, 22...semiconductor layer, 24...anode electrode, 26...cathode electrode, 28...protective layer, 42...top.

Claims

1. A package substrate; a semiconductor light emitting device that is flip-chip bonded onto the package substrate; a frame provided around the semiconductor light emitting element on the package substrate; a sealing member that covers the semiconductor light emitting element on the package substrate, covers an upper surface of the frame, and has translucency at an emission wavelength of the semiconductor light emitting element; A semiconductor light emitting device, wherein the height of the upper surface of the frame is smaller than the height of the upper surface of the semiconductor light emitting element.

2. 2 . The semiconductor light emitting device according to claim 1 , wherein a height from the package substrate to the upper surface of the frame is 20% to 80% of a height from the package substrate to the upper surface of the semiconductor light emitting element.

3. 2 . The semiconductor light emitting device according to claim 1 , wherein a height from the upper surface of the semiconductor light emitting element to a top of the sealing member is smaller than a height from the package substrate to the upper surface of the semiconductor light emitting element.

4. the semiconductor light emitting element includes an anode electrode and a cathode electrode bonded to the package substrate, a semiconductor layer on the anode electrode and the cathode electrode, and a light-transmitting substrate on the semiconductor layer; The semiconductor light emitting device according to claim 1 , wherein the height of the upper surface of the frame is greater than the height of the lower surface of the light-transmitting substrate.

5. The semiconductor light emitting device according to claim 4 , wherein the height of the upper surface of the frame is smaller than an intermediate height at which the thickness of the light-transmitting substrate is half.

6. The semiconductor light emitting device according to claim 4 , wherein a height from the upper surface of the semiconductor light emitting element to a top of the sealing member is smaller than a thickness of the light-transmitting substrate.

7. 7. The semiconductor light emitting device according to claim 4, wherein the light transmissive substrate has a thickness of 300 to 500 [mu]m.

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