Submount, method for manufacturing the same, and light emitting device

Abstract

To provide a submount excellent in heat dissipation.SOLUTION: A submount according to an embodiment of the present disclosure includes a support layer, a first graphite layer disposed on the support layer, a first metal layer disposed on the first graphite layer, and a second metal layer disposed on the first metal layer, wherein the first metal layer is thicker than the second metal layer, and an outer peripheral portion of an upper surface of the first graphite layer is provided with a first region in which the first metal layer is not disposed, the second metal layer covers the first metal layer and the first region of the upper surface of the first graphite layer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a submount, a method for manufacturing the same, and a light emitting device. [Background technology]

[0002] Electronic devices such as light-emitting devices include, for example, a submount on which a light-emitting element is disposed. The submount is required to have high thermal conductivity in order to dissipate heat generated by the light-emitting element. For example, the submount includes a support layer and a graphite layer disposed on the support layer, and the light-emitting element is disposed on the graphite layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-88042 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a submount with excellent heat dissipation properties, a method for manufacturing the same, and a light emitting device having the submount. [Means for solving the problem]

[0005] A submount according to one embodiment of the present disclosure includes a support layer, a first graphite layer disposed on the support layer, a first metal layer disposed on the first graphite layer, and a second metal layer disposed on the first metal layer, wherein the first metal layer is thicker than the second metal layer, a first region where the first metal layer is not disposed is provided around the periphery of the top surface of the first graphite layer, and the second metal layer covers the first metal layer and the first region on the top surface of the first graphite layer.

[0006] A method for manufacturing a submount according to one embodiment of the present disclosure includes the steps of: preparing a laminate having a support layer and a first graphite layer disposed on the support layer; disposing a first metal layer on the first graphite layer; removing a portion of the first metal layer to form a first groove portion that does not cover the first graphite layer; disposing a second metal layer that is thinner than the first metal layer on the first metal layer and on the first graphite layer in the first groove portion that is not covered by the first metal layer; and cutting the second metal layer and the laminate along the first groove portion.

[0007] A light emitting device according to an embodiment of the present disclosure includes a base, a submount according to an embodiment of the present disclosure disposed on the base, and a light emitting element disposed on the second metal layer. [Effects of the Invention]

[0008] According to an embodiment of the present disclosure, it is possible to provide a submount with excellent heat dissipation properties, a method for manufacturing the same, and a light emitting device having the submount. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a top view of the submount 10. [Figure 2] FIG. 2 is a bottom view of the submount 10. [Figure 3] 3 is a cross-sectional view of the submount 10 taken along the line III-III in FIG. [Figure 4] FIG. 2 is a partially enlarged perspective view of a first graphite layer. [Figure 5A] 1A and 1B are cross-sectional views (1) illustrating a method for manufacturing a submount according to the first embodiment. [Figure 5B] FIG. 10 is a cross-sectional view (2) illustrating the method for manufacturing the submount according to the first embodiment. [Figure 5C] FIG. 10 is a cross-sectional view (3) illustrating the method for manufacturing the submount according to the first embodiment. [Figure 5D]FIG. 4 is a cross-sectional view (4) illustrating the method for manufacturing the submount according to the first embodiment. [Figure 5E] FIG. 5 is a cross-sectional view (5) illustrating the method for manufacturing the submount according to the first embodiment. [Figure 6] FIG. 10 is a perspective view illustrating a light emitting device according to a second embodiment. [Figure 7] FIG. 7 is a perspective view of the light emitting device shown in FIG. 6 with a lid removed. [Figure 8] FIG. 8 is a top view of the light emitting device shown in FIG. [Figure 9] 9 is a cross-sectional view of the light emitting device taken along the line IX-IX in FIG. 6. [Figure 10] FIG. 10 is an enlarged view of the area surrounded by the dashed line A in FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a description of an embodiment of the invention will be given with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms including these terms) will be used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not unduly limit the technical scope of the present invention. For example, when the term "upper surface" is used, it does not necessarily mean that the invention must always be used facing upward. Furthermore, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or components.

[0011] Furthermore, in this disclosure, polygons such as triangles and quadrilaterals are referred to as polygons, including shapes in which the corners of the polygons have been processed, such as by rounding, chamfering, corner removal, or rounding. Shapes in which processing has been applied not only to the corners (edges of the sides) but also to the middle portions of the sides are also referred to as polygons. In other words, shapes in which partial processing has been applied while retaining the polygon as a base are included in the interpretation of "polygon" described in this disclosure.

[0012] The same applies to words that represent specific shapes, such as trapezoids, circles, and irregularities, not just polygons. The same also applies when dealing with the sides that form the shape. In other words, even if the corners or middle part of a side have been processed, the interpretation of "side" includes the processed part. Note that when distinguishing a "polygon" or "side" that has no processing from a processed shape, the word "strict" is added, for example, "strict quadrangle."

[0013] Furthermore, the embodiments shown below are intended to exemplify submounts and the like to embody the technical concepts of the present invention, and are not intended to limit the scope of the present invention. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, and the like of the components described below are intended for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, the content described in one embodiment may also be applied to other embodiments and modified examples. Furthermore, the size and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, to avoid overly complex drawings, schematic diagrams may be used in which some elements are omitted, or end views may be used as cross-sectional views showing only the cut surface.

[0014] First Embodiment A submount 10 according to a first embodiment will be described. FIGS. 1 to 3 are diagrams illustrating an exemplary embodiment of the submount 10. FIG. 1 is a top view of the submount 10. FIG. 2 is a bottom view of the submount 10. FIG. 3 is a cross-sectional view of the submount 10 taken along the line III-III in FIG. 1.

[0015] In each drawing, for reference, mutually orthogonal X-, Y-, and Z-axes are shown as necessary. The direction parallel to the X-axis is called the X-direction, the direction parallel to the Y-axis is called the Y-direction, and the direction parallel to the Z-axis is called the Z-direction. In addition, in the X-direction, the direction in which the arrow points is called the +X-direction, and the direction opposite to the +X-direction is called the -X-direction. In the Y-direction, the direction in which the arrow points is called the +Y-direction, and the direction opposite to the +Y-direction is called the -Y-direction. In the Z-direction, the direction in which the arrow points is called the +Z-direction, and the direction opposite to the +Z-direction is called the -Z-direction. However, these do not limit the orientation of the submount when in use, and the orientation of the submount is arbitrary.

[0016] (Submount 10) 1 to 3, submount 10 has support layer 11, first graphite layer 12, first metal layer 13, second metal layer 14, third metal layer 15, second graphite layer 22, fourth metal layer 23, and fifth metal layer 24. Note that submount 10 does not necessarily have to have third metal layer 15, second graphite layer 22, fourth metal layer 23, and fifth metal layer 24.

[0017] The length of the submount 10 in the X direction may be, for example, 0.3 mm or more and 5 mm or less. The length of the submount 10 in the Y direction may be, for example, 0.3 mm or more and 4 mm or less. The length of the submount 10 in the Z direction, i.e., the thickness of the submount 10, may be, for example, 0.3 mm or more and 1.0 mm or less. The length of the submount 10 in the Z direction may be smaller than both the length of the submount 10 in the X direction and the length of the submount 10 in the Y direction.

[0018] The support layer 11 has an upper surface 11a, a lower surface 11b opposite the upper surface 11a, and one or more side surfaces 11c intersecting the upper surface 11a and the lower surface 11b. The one or more side surfaces 11c connect the outer edge of the upper surface 11a to the outer edge of the lower surface 11b. In the illustrated example, the upper surface 11a and the lower surface 11b are parallel. The upper surface 11a and the lower surface 11b do not have to be parallel. In the illustrated example, each side surface 11c is perpendicular to the upper surface 11a and the lower surface 11b. Each side surface 11c does not have to be perpendicular to the upper surface 11a or the lower surface 11b. Note that a difference of 5 degrees is allowed between "parallel" and "perpendicular" here.

[0019] In the illustrated example, the support layer 11 is rectangular in top view. In this case, both the top surface 11a and the bottom surface 11b of the support layer 11 are rectangular, and the support layer 11 has four rectangular side surfaces 11c. The support layer 11 does not have to be rectangular in top view. Note that unless specifically stated to exclude squares, the rectangle may also include squares. The length of the support layer 11 in the Z direction (the thickness of the support layer 11) is shorter than the length in the X direction and the length in the Y direction. The thickness of the support layer 11 may be, for example, 100 μm or more and 400 μm or less.

[0020] The support layer 11 may be made of, for example, ceramic. Specifically, the support layer 11 may be made of, for example, ceramic containing at least one selected from the group consisting of AlN, SiC, silicon nitride, and alumina. The ceramic may be, for example, LTCC (Low Temperature Co-fired Ceramic). Alternatively, the support layer 11 may be formed of a metal selected from the group consisting of Ag, Cu, W, Au, Ni, Pt, and Pd, or an alloy containing multiple metals selected from this group.

[0021] The rigidity of support layer 11 is higher than the rigidity of first graphite layer 12. Furthermore, the thickness of support layer 11 is greater than the thickness of first graphite layer 12. Furthermore, the rigidity of support layer 11 is higher than the rigidity of second graphite layer 22. Furthermore, the thickness of support layer 11 is greater than the thickness of second graphite layer 22. By supporting the brittle first graphite layer 12 or second graphite layer 22 with the thick and rigid support layer 11, the mechanical strength of submount 10 can be improved.

[0022] First graphite layer 12 has an upper surface 12a, a lower surface 12b opposite to upper surface 12a, and one or more side surfaces 12c intersecting with upper surface 12a and lower surface 12b. One or more side surfaces 12c connect the outer edge of upper surface 12a to the outer edge of lower surface 12b. In the illustrated example, upper surface 12a and lower surface 12b are parallel. Upper surface 12a and lower surface 12b do not have to be parallel. In the illustrated example, each side surface 12c is perpendicular to upper surface 12a and lower surface 12b. Each side surface 12c does not have to be perpendicular to upper surface 12a or lower surface 12b. The thickness of first graphite layer 12 can be, for example, 50 μm or more and 200 μm or less.

[0023] First graphite layer 12 is disposed on support layer 11. First graphite layer 12 may be disposed, for example, over the entire upper surface 11a of support layer 11. Each side surface 12c of first graphite layer 12 is not covered by first metal layer 13 or second metal layer 14. One side surface 12c of first graphite layer 12 may be flush with one side surface 11c of support layer 11. When there are multiple side surfaces 12c of first graphite layer 12 and multiple side surfaces 11c of support layer 11, there may be multiple pairs of side surfaces 12c of first graphite layer 12 and side surfaces 11c of support layer 11 that are flush with each other. Furthermore, when some of the plurality of side surfaces 12c of first graphite layer 12 are flush with some of the plurality of side surfaces 11c of support layer 11, the remaining of the plurality of side surfaces 12c of first graphite layer 12 do not have to be flush with the remaining of the plurality of side surfaces 11c of support layer 11. In the illustrated example, there are four pairs of flush-mounted side surfaces 12c of first graphite layer 12 and side surfaces 11c of support layer 11. In the illustrated example, at least a part of the outer edge of upper surface 11a of support layer 11 coincides with the outer edge of first graphite layer 12 in a top view.

[0024] When light emitting element 220 is disposed on submount 10, the larger the overlapping area between lower surface 12b of first graphite layer 12 and upper surface 11a of support layer 11, the more efficiently submount 10 can dissipate heat generated by light emitting element 220. From this perspective, it is preferable that the outer edge of lower surface 12b of first graphite layer 12 coincides with the outer edge of upper surface 11a of support layer 11 in a top view. In the illustrated example, the outer edge of lower surface 12b of first graphite layer 12 coincides with the outer edge of upper surface 11a of support layer 11 in a top view.

[0025] FIG. 4 is a partially enlarged perspective view of the first graphite layer. As schematically shown in FIG. 4, the first graphite layer 12 has a plurality of graphenes 12g stacked in the X direction. Each of the plurality of graphenes extends in the YZ plane, with its extent (width) in the Y direction being greater than its extent (width) in the Z direction. Each graphene 12g has a planar shape parallel to the YZ plane due to a honeycomb structure formed by covalent bonds between a plurality of carbon atoms. Two graphenes 12g adjacent to each other in the X direction are bonded by van der Waals forces. In reality, the distance in the X direction between two adjacent graphenes 12g is extremely narrow, about 0.3 nm to 0.4 nm, but is exaggerated in the example shown in FIG. 4.

[0026] Phonons are the primary heat-conducting carrier in each graphene 12g, rather than electrons. Heat is more easily transferred within the plane of each graphene 12g than between two adjacent graphenes 12g. Therefore, the thermal conductivity of the first graphite layer 12 in the YZ plane direction is extremely high, but conversely, the thermal conductivity of the first graphite layer 12 in the X direction is not so high. Specifically, the thermal conductivity of the first graphite layer 12 in the YZ plane direction is, for example, 1700 W / mK, and the thermal conductivity in the X direction is, for example, 7 W / mK. As described above, the first graphite layer 12 has high anisotropy in thermal conductivity.

[0027] The first metal layer 13 is disposed on the first graphite layer 12. The first metal layer 13 is thicker than the second metal layer 14. The thickness of the first metal layer 13 can be, for example, 5 μm or more and 100 μm or less. Preferably, the thickness is 5 μm or more and 50 μm or less. A thickness of 5 μm or more can reduce absorption of ultrasonic waves by the first graphite layer 12 when ultrasonically bonding the wiring 270, thereby increasing the bonding strength with the wiring 270. Furthermore, a thickness of 50 μm or less can improve heat dissipation to the first graphite layer 12 and facilitate the formation of the first groove portion 13x during manufacturing. The first metal layer 13 can contain, for example, copper. The first metal layer 13 is not disposed over the entire upper surface 12a of the first graphite layer 12. Specifically, the first metal layer 13 is not disposed in a first region R1 of the outer periphery of the upper surface 12a of the first graphite layer 12. In other words, the outer periphery of top surface 12a of first graphite layer 12 is provided with first region R1 where first metal layer 13 is not arranged.

[0028] Here, the outer periphery of upper surface 12a of first graphite layer 12 refers to the outer edge of upper surface 12a and the region in the vicinity thereof. The outer periphery can be defined as, for example, a region of upper surface 12a that is 100 μm or less away from the outer edge of upper surface 12a. Alternatively, the outer periphery can be defined as, for example, a region of upper surface 12a that is 30 μm or less away from the outer edge of upper surface 12a.

[0029] First region R1 is a region that includes at least one side and its vicinity among one or more sides that form the outer edge of first graphite layer 12 in a top view. First region R1 can be a region that includes at least two opposing sides and their vicinity among the multiple sides that form the outer edge of first graphite layer 12 in a top view. First region R1 can be a region that includes at least two opposing first sides and their vicinity and two opposing second sides and their vicinity among the multiple sides that form the outer edge of first graphite layer 12 in a top view. First region R1 can be a peripheral portion of top surface 12a.

[0030] In a top view, the outer edge of top surface 12a of first graphite layer 12 is within a predetermined distance from the outer edge of first metal layer 13. The predetermined distance range is, for example, 100 μm or less. Another example of the predetermined distance range is 20 μm or more and 100 μm or less. By making the distance from the outer edge of first metal layer 13 to the outer edge of top surface 12a 20 μm or more in a top view, submount 10 can be manufactured stably. By keeping this distance 100 μm or less, the entire surface of first graphite layer 12 can be efficiently utilized for heat dissipation.

[0031] In top view, a portion of the outer edge of first graphite layer 12 is located within 100 μm of at least one of one or more sides that form the outer edge of first metal layer 13. In top view, a portion of the outer edge of first graphite layer 12 is located within 100 μm of each of at least two opposing sides of the multiple sides that form the outer edge of first metal layer 13.

[0032] It is preferable that the area of ​​first metal layer 13 is larger than the area of ​​first region R1 in a top view. The ratio of the area of ​​the lower surface of first metal layer 13 to the area of ​​upper surface 12a of first graphite layer 12 in a top view is, for example, 70%. Furthermore, this ratio is preferably 90% or more. By arranging first metal layer 13, which is relatively thick, over a wide area, first graphite layer 12 is protected by first metal layer 13 when first graphite layer 12 is cut, and therefore, it is possible to reduce the occurrence of large chips that extend from the cut portion of first graphite layer 12 to just below first metal layer 13.

[0033] For example, when first graphite layer 12 has a rectangular shape having long and short sides in a top view, first region R1 includes at least the short sides and their vicinity. In this case, first region R1 is provided along at least the short sides. First region R1 may include only one of the opposing short sides and its vicinity, or may include both sides and their vicinity. Furthermore, first region R1 may include only one of the opposing long sides and its vicinity, or may include both sides and their vicinity. First region R1 may be provided along only one of the sides of first graphite layer 12, or may be provided along all sides. In the illustrated example, first region R1 is provided in an annular shape on top surface 12a of first graphite layer 12. By providing first region R1 in an annular shape on the outer periphery of top surface 12a of first graphite layer 12, no burrs resulting from cutting first metal layer 13 are generated along any of the sides of first graphite layer 12.

[0034] Second metal layer 14 is disposed on first metal layer 13. Second metal layer 14 is disposed on the top surface 12a side of first graphite layer 12. Second metal layer 14 covers first metal layer 13 and first region R1 on top surface 12a of first graphite layer 12. Second metal layer 14 may cover the side surface of first metal layer 13. Second metal layer 14 covers the outer periphery of first graphite layer 12. Second metal layer 14 covers top surface 12a of first graphite layer 12 exposed from first metal layer 13.

[0035] The thickness of the second metal layer 14 is thinner than the thickness of the first metal layer 13. The first metal layer 13 may be thicker than the second metal layer 14 by 10 μm or more. The first metal layer 13 may be thicker than the second metal layer 14 by 20 μm or more. The thickness of the second metal layer 14 may be, for example, 0.3 μm or more and 10 μm or less. The ratio of the thickness of the second metal layer 14 to the thickness of the first metal layer 13 may be, for example, 2% to 10%. The second metal layer 14 may include at least one metal selected from the group consisting of titanium, platinum, and gold, for example.

[0036] A third metal layer 15 may be further disposed on the second metal layer 14. Specifically, the third metal layer 15 can be used as a bonding material when disposing the light emitting element 220 on the second metal layer 14. The third metal layer 15 is disposed at a position overlapping a portion of the second metal layer 14 in a top view. In other words, the third metal layer 15 is not disposed on the entire second metal layer 14 in a top view. One or more third metal layers 15 are disposed on the second metal layer 14. The third metal layer 15 is disposed at a position overlapping the first metal layer 13 in a top view. The third metal layer 15 does not overlap the outer edge of the first graphite layer 12 in a top view. The third metal layer 15 is not disposed at a position not overlapping the first metal layer 13 in a top view.

[0037] The thickness of the third metal layer 15 may be, for example, 1 μm or more and 10 μm or less. The third metal layer 15 may be formed of, for example, at least one alloy selected from the group consisting of AuSn, SnCu, SnAg, and SnAgCu. Alternatively, the third metal layer 15 may be formed of at least one alloy selected from the group consisting of gold brazing filler metal, silver brazing filler metal, and copper brazing filler metal. Alternatively, the third metal layer 15 may be formed of a metal containing at least one type of particle selected from the group consisting of Ag particles, Cu particles, and Au particles.

[0038] When the third metal layer 15 is formed from AuSn or the like, high adhesion cannot be obtained if the first metal layer 13 is made of copper. By providing a gold layer or the like on the first metal layer 13, which has better adhesion to the third metal layer than the first metal layer 13, the adhesion to the third metal layer 15 can be improved.

[0039] The second graphite layer 22 has an upper surface 22a, a lower surface 22b opposite the upper surface 22a, and one or more side surfaces 22c intersecting the upper surface 22a and the lower surface 22b. The one or more side surfaces 22c connect the outer edge of the upper surface 22a to the outer edge of the lower surface 22b. In the illustrated example, the upper surface 22a and the lower surface 22b are parallel. The upper surface 22a and the lower surface 22b do not have to be parallel. In the illustrated example, each side surface 22c is perpendicular to the upper surface 22a and the lower surface 22b. The side surfaces 22c do not have to be perpendicular to the upper surface 22a or the lower surface 22b. The thickness of the second graphite layer 22 may be, for example, 50 μm or more and 200 μm or less. The thickness of the second graphite layer 22 and the thickness of the first graphite layer 12 may be the same or different. The second graphite layer may be the same graphite layer as the first graphite layer.

[0040] Second graphite layer 22 is disposed below support layer 11. Second graphite layer 22 may be disposed, for example, over the entire lower surface 11b of support layer 11. Side surfaces 22c of second graphite layer 22 are not covered by fourth metal layer 23 and fifth metal layer 24. One side surface 22c of second graphite layer 22 may be flush with one side surface 11c of support layer 11. When there are multiple side surfaces 22c of second graphite layer 22 and multiple side surfaces 11c of support layer 11, there may be multiple pairs of side surfaces 22c of second graphite layer 22 and side surfaces 11c of support layer 11 that are flush with each other. Furthermore, when some of the multiple side surfaces 22c of second graphite layer 22 are flush with some of the multiple side surfaces 11c of support layer 11, the remaining side surfaces of the multiple side surfaces 22c of second graphite layer 22 do not have to be flush with the remaining side surfaces of the multiple side surfaces 11c of support layer 11. In the illustrated example, there are four pairs of flush-mounted side surfaces 22c of second graphite layer 22 and side surfaces 11c of support layer 11. In the illustrated example, the outer edge of lower surface 11b of support layer 11 coincides with the outer edge of second graphite layer 22 in bottom view. Similar to first graphite layer 12, second graphite layer 22 has a plurality of graphenes stacked in the X direction.

[0041] When light emitting element 220 is disposed on submount 10, the larger the overlapping area between upper surface 22a of second graphite layer 22 and lower surface 11b of support layer 11, the more efficiently submount 10 can dissipate heat generated by light emitting element 220. From this perspective, it is preferable that the outer edge of upper surface 22a of second graphite layer 22 coincides with the outer edge of lower surface 11b of support layer 11 when viewed from below. In the illustrated example, the outer edge of upper surface 22a of second graphite layer 22 coincides with the outer edge of lower surface 11b of support layer 11 when viewed from above.

[0042] The fourth metal layer 23 is disposed under the second graphite layer 22. The fourth metal layer 23 is thicker than the fifth metal layer 24. The thickness of the fourth metal layer 23 may be the same as or different from the thickness of the first metal layer 13. The fourth metal layer 23 may be made of the same metal material as the first metal layer 13. For example, if the first metal layer 13 is a copper-plated layer, the fourth metal layer 23 may also be a copper-plated layer. The fourth metal layer 23 may be made of a material different from that of the first metal layer 13. The fourth metal layer 23 is not disposed over the entire lower surface 22b of the second graphite layer 22. Specifically, the fourth metal layer 23 is not disposed in the second region R2 of the outer periphery of the lower surface 22b of the second graphite layer 22. In other words, the second region R2 where the fourth metal layer 23 is not disposed is provided in the outer periphery of the lower surface 22b of the second graphite layer 22.

[0043] Here, the outer peripheral portion of lower surface 22b of second graphite layer 22 refers to the outer edge of lower surface 22b and the region in the vicinity thereof. The outer peripheral portion can be defined as, for example, a region of lower surface 22b that is 100 μm or less away from the outer edge of lower surface 22b. Alternatively, the outer peripheral portion can be defined as, for example, a region of lower surface 22b that is 30 μm or less away from the outer edge of lower surface 22b.

[0044] When viewed from the bottom, the outer edge of lower surface 22b of second graphite layer 22 is within a predetermined distance from the outer edge of fourth metal layer 23. The predetermined distance is, for example, 100 μm or less. Another example of the predetermined distance range is 20 μm or more and 100 μm or less. By making the distance from the outer edge of fourth metal layer 23 to the outer edge of lower surface 22b 20 μm or more when viewed from the bottom, submount 10 can be manufactured stably. By keeping this distance 100 μm or less, the entire surface of second graphite layer 22 can be efficiently utilized for heat dissipation.

[0045] When viewed from below, a portion of the outer edge of second graphite layer 22 is located within 100 μm of at least one of one or more sides that form the outer edge of fourth metal layer 23. When viewed from below, a portion of the outer edge of second graphite layer 22 is located within 100 μm of each of at least two opposing sides of the multiple sides that form the outer edge of fourth metal layer 23.

[0046] It is preferable that the area of ​​fourth metal layer 23 is larger than the area of ​​second region R2 when viewed from below. The ratio of the area of ​​the lower surface of fourth metal layer 23 to the area of ​​lower surface 22b of second graphite layer 22 when viewed from below is, for example, 70%. Furthermore, this ratio is preferably 90% or more. By arranging fourth metal layer 23, which is relatively thick, over a wide area, second graphite layer 22 is protected by fourth metal layer 23 when second graphite layer 22 is cut, and this makes it possible to reduce the occurrence of large chips that extend from the cut portion of second graphite layer 22 to directly above fourth metal layer 23.

[0047] For example, when second graphite layer 22 has a rectangular shape having long and short sides when viewed from below, second region R2 is preferably provided in an annular shape along the long and short sides. Second region R2 may be provided, for example, at a position overlapping first region R1 when viewed from above. The width of second region R2 may be the same as the width of first region R1. The width of second region R2 may be different from the width of first region R1. By providing second region R2 in an annular shape on the outer periphery of lower surface 22b of second graphite layer 22, burrs due to cutting fourth metal layer 23 are prevented from occurring along all sides of second graphite layer 22.

[0048] Fifth metal layer 24 is disposed below fourth metal layer 23. Fifth metal layer 24 is disposed on the lower surface 22b side of second graphite layer 22. Fifth metal layer 24 covers fourth metal layer 23 and second region R2 on lower surface 22b of second graphite layer 22. Fifth metal layer 24 may cover the side surfaces of fourth metal layer 23. Fifth metal layer 24 covers the outer periphery of second graphite layer 22. Fifth metal layer 24 covers lower surface 22b of second graphite layer 22 exposed from fourth metal layer 23.

[0049] The thickness of the fifth metal layer 24 is thinner than the thickness of the fourth metal layer 23. The fourth metal layer 23 can be thicker than the fifth metal layer 24 by 10 μm or more. The fourth metal layer 23 can be thicker than the fifth metal layer 24 by 20 μm or more. The thickness of the fifth metal layer 24 can be, for example, 0.3 μm or more and 10 μm or less. The ratio of the thickness of the fifth metal layer 24 to the thickness of the fourth metal layer 23 can be, for example, 2% to 10%. The thickness of the fifth metal layer 24 can be the same as that of the second metal layer 14, for example. The thickness of the fifth metal layer 24 can be different from that of the second metal layer 14. The fifth metal layer 24 can be made of, for example, the same metal material as the second metal layer 14. The fifth metal layer 24 can be made of a different material than the second metal layer 14.

[0050] (Method of manufacturing the submount 10) A method for manufacturing the submount 10 according to the first embodiment will be described with reference to Figures 5A to 5E. Figures 5A to 5E are cross-sectional views illustrating an example of the method for manufacturing the submount according to the first embodiment.

[0051] [Step of preparing laminate] First, as shown in FIG. 5A, a laminate 100 having a support layer 11, a first graphite layer 12 disposed on the support layer 11, and a second graphite layer 22 disposed below the support layer 11 is prepared.

[0052] Specifically, first, graphite for forming first graphite layer 12 and second graphite layer 22 is prepared and cut to the required size. The graphite is a laminate of multiple graphene sheets. The graphene sheets constituting the graphite have a honeycomb structure formed by covalent bonds between multiple carbon atoms, similar to each graphene 12g shown in FIG. 4. Two adjacent graphene sheets are bonded by van der Waals forces, similar to the two adjacent graphenes 12g shown in FIG. 4.

[0053] Next, graphite is disposed above and below support layer 11 and bonded. This completes laminate 100, which includes support layer 11, first graphite layer 12 disposed above support layer 11, and second graphite layer 22 disposed below support layer 11. That is, the graphite disposed above support layer 11 becomes first graphite layer 12, and the graphite disposed below support layer 11 becomes second graphite layer 22. Each piece of graphite and support layer 11 are bonded together, for example, by room-temperature bonding. Specifically, upper surface 11a and lower surface 11b of support layer 11, lower surface 12b of first graphite layer 12, and upper surface 22a of second graphite layer 22 are polished, and the opposing surfaces are bonded to each other by intermolecular forces at room temperature. If necessary, upper surface 12a of first graphite layer 12 and lower surface 22b of second graphite layer 22 may be polished to thin them.

[0054] [Step of disposing the first metal layer 13 and the fourth metal layer 23] 5B, a first metal layer 13 is disposed on the first graphite layer 12. A fourth metal layer 23 is disposed under the second graphite layer 22. The first metal layer 13 and the fourth metal layer 23 can be disposed by, for example, plating, sputtering, vapor deposition, or the like.

[0055] If the adhesion between first metal layer 13 and first graphite layer 12 is low, a metal layer made of a material different from that of first metal layer 13 may be disposed between first metal layer 13 and first graphite layer 12. For example, if copper is plated as first metal layer 13, the adhesion can be improved by disposing a nickel layer having a thickness of about several μm to 30 μm between first metal layer 13 and first graphite layer 12. The same applies to the case where the adhesion between fourth metal layer 23 and second graphite layer 22 is low.

[0056] [Step of forming the first groove portion 13x and the second groove portion 23x] Next, as shown in FIG. 5C , a portion of the first metal layer 13 is removed to form a first groove 13x that does not cover the first graphite layer 12. The first groove 13x exposes the top surface 12a of the first graphite layer 12. The side surfaces of the first metal layer 13 exposed by the formation of the first groove 13x become the side surfaces of the submount 10. A portion of the fourth metal layer 23 is also removed to form a second groove 23x that does not cover the second graphite layer 22 in a bottom view. The second groove 23x exposes the bottom surface 22b of the second graphite layer 22. The side surfaces of the second metal layer 14 exposed by the formation of the second groove 23x become the side surfaces of the submount 10. The first groove 13x and the second groove 23x can be formed, for example, in a grid pattern in the X and Y directions when viewed from above. The first groove 13x and the second groove 23x can be formed, for example, by etching. 5B, the first grooves 13x and the second grooves 23x can be simultaneously formed by forming a mask on areas other than the areas where the first grooves 13x and the second grooves 23x are to be formed and immersing the structure in an etching solution. The widths of the first grooves 13x and the second grooves 23x are determined in consideration of the widths of the first region R1 and the second region R2 and the width removed by a blade or the like during cutting.

[0057] [Step of disposing the second metal layer 14 and the fifth metal layer 24] 5D , a second metal layer 14 thinner than the first metal layer 13 is disposed on the first metal layer 13 and on the first graphite layer 12 in the first groove 13x that is not covered by the first metal layer 13. A fifth metal layer 24 thinner than the fourth metal layer 23 is disposed below the fourth metal layer 23 and below the second graphite layer 22 in the second groove 23x that is not covered by the fourth metal layer 23. The second metal layer 14 and the fifth metal layer 24 can be disposed by, for example, sputtering, plating, vapor deposition, or the like.

[0058] [Cutting process] Next, as shown in FIG. 5E , the second metal layer 14, the laminate 100, and the fifth metal layer 24 are cut along the first grooves 13x and the second grooves 23x. This cuts the laminate 100, the second metal layer 14, and the fifth metal layer 24, forming multiple submounts 10. The side surfaces of the laminate 100 exposed by this cutting, i.e., the side surface 11c of the support layer 11, the side surface 12c of the first graphite layer 12, the side surface 22c of the second graphite layer 22, the side surface of the second metal layer 14, and the side surface of the fifth metal layer 24, become the side surfaces of the submount 10. For example, a blade or a laser can be used for cutting. If necessary, a third metal layer 15 may be disposed on the second metal layer 14 after or before the cutting process.

[0059] In this way, in submount 10, first metal layer 13, which is relatively thick, is disposed in a portion other than first region R1. As a result, when first graphite layer 12 is cut, first graphite layer 12 is protected by first metal layer 13, thereby reducing the possibility of large chipping that begins at the cut portion of first graphite layer 12 and extends to just below first metal layer 13. In the manufacturing process of submount 10, first region R1 can be defined as the region from the outer edge of first metal layer 13 to the cut edge, when viewed from above. Similarly, fourth metal layer 23, which is relatively thick, is disposed in a portion other than second region R2. As a result, when second graphite layer 22 is cut, second graphite layer 22 is protected by fourth metal layer 23, thereby reducing the possibility of large chipping that begins at the cut portion of second graphite layer 22 and extends to just above fourth metal layer 23. In the manufacturing process of the submount 10, the second region R2 can be said to be the region from the outer edge of the fourth metal layer 23 to the cutting edge when viewed from below.

[0060] The target value of the cutting position can be approximately 10 μm to 20 μm from the outer edge of first metal layer 13 when viewed from above. By bringing the cutting position closer to the outer edge of first metal layer 13, it is possible to reduce the size of chipping in first graphite layer 12 that occurs in first region R1, with the cut portion as the end. Similarly, the target value of the cutting position can be approximately 10 μm to 20 μm from the outer edge of fourth metal layer 23 when viewed from below. By bringing the cutting position closer to the outer edge of fourth metal layer 23, it is possible to reduce the size of chipping in second graphite layer 22 that occurs in second region R2, with the cut portion as the end.

[0061] Furthermore, because the submount 10 is cut along the first region R1 and the second region R2 to separate the submount 10, the relatively thick first metal layer 13 and fourth metal layer 23 are not cut. Therefore, no burrs resulting from cutting the first metal layer 13 and the fourth metal layer 23 are generated near the cut portions of the submount 10. For example, as shown in FIG. 10 (described later), when a light-emitting element 220 is disposed on the submount 10, the light-emitting end surface 220a of the light-emitting element 220 is located near the edge of the submount 10. Therefore, if a burr on the first metal layer 13 exists near the edge of the submount 10, the burr may cause the light-emitting element 220 to float, preventing it from being positioned correctly. Furthermore, the burr may impede the travel of light emitted from the light-emitting element 220. However, since the submount 10 does not have burrs near the edge due to cutting the first metal layer 13, such a problem does not occur.

[0062] Furthermore, if there are burrs on the fourth metal layer 23 near the edges of the submount 10 when placing the submount 10 on the base 211, the burrs may cause the submount 10 itself to float, preventing it from being placed in the correct position. However, with the submount 10, there are no burrs on the fourth metal layer 23 near the edges, so this problem does not occur.

[0063] Furthermore, because the second metal layer 14 and the fifth metal layer 24 are relatively thin, burrs resulting from cutting the second metal layer 14 and the fifth metal layer 24 can be small. If the burrs resulting from cutting the second metal layer 14 are small, there is little risk that the burrs will protrude from the upper surface of the second metal layer 14 located above the first metal layer 13. This will therefore not affect the arrangement of the light emitting element 220 or the propagation of light emitted from the light emitting element 220. Similarly, if the burrs resulting from cutting the fifth metal layer 24 are small, there is little risk that the burrs will protrude from the lower surface of the fifth metal layer 24 located below the fourth metal layer 23. This will therefore not affect the arrangement of the submount 10 itself.

[0064] Furthermore, the method for manufacturing submount 10 does not require the step of etching first graphite layer 12 and second graphite layer 22, which are difficult to etch. This allows first graphite layer 12 and second graphite layer 22 to be thicker, thereby reducing the thermal resistance of first graphite layer 12 and second graphite layer 22 and improving the heat dissipation performance of submount 10.

[0065] Second Embodiment In the second embodiment, an example of a light emitting device including the submount according to the first embodiment is shown. FIG. 6 is a perspective view illustrating the light emitting device according to the second embodiment. FIG. 7 is a perspective view of the light emitting device shown in FIG. 6 with the lid removed. FIG. 8 is a top view of the light emitting device shown in FIG. 7. FIG. 9 is a cross-sectional view of the light emitting device taken along the line IX-IX in FIG. 6. FIG. 10 is an enlarged view of the area surrounded by dashed line A in FIG. 9. Note that the submount 10 is shown in a simplified form in FIG. 9, but the details are as shown in FIG. 10.

[0066] As shown in Figures 6 to 10, the light emitting device 200 according to the second embodiment has the submount 10 according to the first embodiment, a base 211, a frame 212, a lid 213, a light emitting element 220, a reflecting member 240, and wiring 270.

[0067] Each component of the light emitting device 200 will be described.

[0068] (base 211) The base 211 has an upper surface 211a and a lower surface. The base 211 has a rectangular outer shape when viewed from above. This rectangle may have long and short sides. The outer shape of the base 211 when viewed from above does not have to be rectangular. The base 211 can be formed, for example, with a metal as the main material. For example, copper, copper alloy, etc. can be used as the metal. The base 211 may also be formed from a main material other than metal, for example, ceramic.

[0069] (frame portion 212) The frame portion 212 has an upper surface 212a, a lower surface, one or more inner surface(s), and one or more outer surface(s). The frame portion 212 has, for example, a rectangular frame shape when viewed from above. The frame portion 212 further has step surfaces 212e and 212f that are located above the upper surface 211a of the base portion 211 and below the upper surface 212a of the frame portion 212. The step surfaces 212e and 212f may be parallel to the upper surface 211a of the base portion 211, for example. In the example shown in the figure, the step surfaces 212e and 212f are provided along two opposing inner surface(s) of the frame portion 212 when viewed from above.

[0070] One or more metal films may be provided on the step surfaces 212e and 212f. Furthermore, one or more metal films may be provided on the lower surface of the base 211 and / or the lower surface of the frame 212. The metal films provided on the step surfaces 212e and 212f and the metal films provided on the lower surface of the base 211 and / or the lower surface of the frame 212 may be electrically connected through vias, for example. The metal films may be, for example, Ni / Au (metal films formed by laminating Ni and Au in this order) or Ti / Pt / Au (metal films formed by laminating Ti, Pt, and Au in this order).

[0071] The frame 212 can be formed, for example, primarily from ceramic, such as aluminum nitride, silicon nitride, aluminum oxide, or silicon carbide.

[0072] The base 211 and the frame 212 form a concave shape recessed from the upper surface 212a of the frame 212 toward the upper surface 211a of the base 211. The concave shape is formed inside the outer shape of the frame 212 when viewed from above. In the example shown, the base 211 and the frame 212 are formed separately and then joined together. Note that the base 211 and the frame 212 may also be formed integrally using the same main material.

[0073] (Lid part 213) The lid portion 213 has an upper surface, a lower surface, and one or more side surfaces that intersect with the upper and lower surfaces. The one or more side surfaces connect the outer edge of the upper surface to the outer edge of the lower surface. The lid portion 213 is, for example, a rectangular parallelepiped or a cube. In this case, both the upper and lower surfaces of the lid portion 213 are rectangular, and the lid portion 213 has four rectangular side surfaces.

[0074] However, the shape of the lid portion 213 is not limited to a rectangular parallelepiped or a cube. That is, the shape of the lid portion 213 is not limited to a rectangle when viewed from above, and can be any shape such as a circle, an ellipse, or a polygon.

[0075] The lid portion 213 is supported by the frame portion 212. The lid portion 213 is disposed above the upper surface 211a of the base portion 211. The outer periphery of the lower surface of the lid portion 213 is joined to, for example, the upper surface 212a of the frame portion 212. By joining the lid portion 213 to the frame portion 212, a sealed space surrounded by the base portion 211, the frame portion 212, and the lid portion 213 is formed.

[0076] The lid portion 213 has a light-transmitting region that transmits light of a predetermined wavelength. The light-transmitting region constitutes at least a portion of the upper and lower surfaces of the lid portion 213. The light-transmitting region of the lid portion 213 can be formed, for example, using sapphire as the main material. Sapphire is a material that has a relatively high transmittance and is also relatively strong. Note that, in addition to sapphire, the main material of the light-transmitting region of the lid portion 213 may be a light-transmitting material including, for example, quartz, silicon carbide, or glass. The portions of the lid portion 213 other than the light-transmitting region may be formed integrally with the light-transmitting region using the same material as the light-transmitting region.

[0077] (light-emitting element 220) In the illustrated example of the light emitting device 200, one light emitting element 220 is mounted. The light emitting device 200 may also be mounted with a plurality of light emitting elements. The light emitting element 220 is, for example, a semiconductor laser element. The semiconductor laser element may be an edge-emitting laser or a vertical-cavity surface-emitting laser (VCSEL). The light emitting element 220 is not limited to a semiconductor laser element, and may also be, for example, a light emitting diode (LED) or an organic light emitting diode (OLED).

[0078] The light-emitting element 220 may be a light-emitting element that emits visible light. Examples of light-emitting elements that emit visible light include light-emitting elements that emit blue light, green light, and red light. Here, the light-emitting elements that emit blue light, green light, and red light refer to light-emitting elements that emit light with peak emission wavelengths in the ranges of 405 nm to 494 nm, 495 nm to 570 nm, and 605 nm to 750 nm, respectively. Examples of the light-emitting element 220 that emits blue or green light include semiconductor laser elements containing nitride semiconductors. Examples of nitride semiconductors that can be used include GaN, InGaN, or AlGaN. Examples of the light-emitting element 220 that emits red light include semiconductor laser elements containing InAlGaP-based, GaInP-based, GaAs-based, and AlGaAs-based semiconductors.

[0079] It should be noted that the emission peak of the light emitted from the light-emitting element 220 is not limited to this. For example, the light emitted from the light-emitting element 220 may be visible light other than the above-mentioned colors, and a light-emitting element that emits ultraviolet light, infrared light, or the like in addition to visible light may be used. Furthermore, a metal film may be provided on the upper and lower surfaces of the light-emitting element 220.

[0080] (Reflective member 240) The reflecting member 240 has a lower surface, multiple side surfaces, and a light-reflecting surface inclined relative to the lower surface. The multiple side surfaces include two side surfaces facing each other across the light-reflecting surface. The light-reflecting surface preferably has a light reflectance of 90% or more for the peak wavelength of the irradiated light. The light-reflecting surface is, for example, a flat surface. The inclination angle of the light-reflecting surface relative to the lower surface is in the range of 10 degrees to 80 degrees, for example, 45 degrees.

[0081] The reflecting member 240 can be made of glass, metal, or the like as the main material forming its outer shape. The main material is preferably a heat-resistant material, such as glass such as quartz or BK7 (borosilicate glass), metal such as aluminum, or Si. The light-reflecting surface can be made of metal such as Ag or Al, or a dielectric multilayer film such as Ta2O5 / SiO2, TiO2 / SiO2, or Nb2O5 / SiO2.

[0082] (Wiring 270) The wiring 270 is made of a conductor having a linear shape with joints at both ends. In other words, the wiring 270 has joints at both ends of the linear portion that are joined to other components. The wiring 270 is used for electrical connection between two components. For example, a metal wire can be used as the wiring 270. Examples of metals include gold, aluminum, silver, copper, and tungsten.

[0083] (Light emitting device 200) In the light emitting device 200, the submount 10 and the reflecting member 240 are disposed on a base 211. In the example of Fig. 10, the fifth metal layer 24 of the submount 10 is bonded to a metal film 215 provided on the upper surface 211a of the base 211 via a bonding portion 214. The bonding portion 214 is made of, for example, Au-Sn. In addition, the metal film provided on the lower surface of the reflecting member 240 is bonded to the metal film provided on the upper surface 211a of the base 211 via Au-Sn.

[0084] The light emitting element 220 is disposed on the submount 10. Specifically, the light emitting element 220 is disposed on the second metal layer 14 of the submount 10. In the example of Fig. 10, a metal film 221 formed on the lower surface of the light emitting element 220 and the second metal layer 14 of the submount 10 are bonded via a third metal layer 15. The light emitting element 220 can be disposed, for example, such that the emission end surface 220a faces the light reflecting surface side of the reflecting member 240.

[0085] If the light-emitting element 220 is an edge-emitting laser, the first region R1 is provided at least in the direction in which the edge-emitting laser emits light. This prevents burrs from obstructing the progression of light emitted from the light-emitting element 220. For example, if the light-emitting element emits light in all directions, it is preferable to provide the first region R1 in a frame shape to suppress burrs over the entire outer periphery of the submount 10.

[0086] The light-emitting element 220 is electrically connected to the metal film provided on the stepped surface 212e via a wiring 270. For example, one end of the wiring 270 is joined to the metal film provided on the upper surface of the light-emitting element 220, and the other end of the wiring 270 is joined to the metal film provided on the stepped surface 212e. The second metal layer 14 of the submount 10 is electrically connected to the metal film provided on the stepped surface 212f via the wiring 270. For example, one end of the wiring 270 is joined to the second metal layer 14, and the other end of the wiring 270 is joined to the metal film provided on the stepped surface 212f. For example, a metal film provided on the lower surface of the base 211 can be used to electrically connect the light-emitting element 220 to an external power supply.

[0087] The wiring 270 can be bonded to the metal film and second metal layer 14 by, for example, ultrasonic bonding. When ultrasonically bonding the wiring 270 and the second metal layer 14, if the second metal layer 14 is formed directly on the first graphite layer 12, the second metal layer 14 is thin, and therefore the ultrasonic waves are absorbed by the first graphite layer 12, which has low rigidity, via the second metal layer 14. If the ultrasonic waves are absorbed by the first graphite layer 12, it becomes difficult to bond the wiring 270 to the second metal layer 14.

[0088] However, in submount 10, first metal layer 13, which is thicker than second metal layer 14, is disposed between second metal layer 14 and first graphite layer 12. This makes it difficult for ultrasonic waves to be absorbed by first graphite layer 12, facilitating ultrasonic bonding between wiring 270 and second metal layer 14. From the viewpoint of making it difficult for ultrasonic waves to be absorbed by first graphite layer 12, it is preferable that the thickness of first metal layer 13 be 5 μm or more.

[0089] The lid portion 213 is disposed on the upper surface 212a of the frame portion 212. Specifically, the lid portion 213 is supported by the upper surface 212a of the frame portion 212, and is disposed above the light emitting element 220 surrounded by the frame portion 212. The outer periphery of the lower surface of the lid portion 213 is bonded to, for example, the upper surface 212a of the frame portion 212. For example, a metal film provided on the outer periphery of the lower surface of the lid portion 213 and a metal film provided on the upper surface 212a of the frame portion 212 are bonded and fixed via Au—Sn or the like.

[0090] The lid portion 213 is joined to the upper surface 212a of the frame portion 212 to form a sealed space in which the light emitting element 220 and the reflecting member 240 are disposed. This sealed space may be formed in an airtight sealed state. For example, when an edge-emitting laser is used as the light emitting element 220, it is preferable to place the light emitting element 220 in an airtight sealed space because organic matter and the like easily collects on the emission end surface 220a. When the light emitting element 220 emits light with a wavelength shorter than that of green, it is preferable to place the light emitting element 220 in an airtight sealed space because organic matter and the like easily collects on the emission end surface 220a. Therefore, when an edge-emitting laser that emits light with a wavelength shorter than that of green is used as the light emitting element 220, it is particularly preferable to place the light emitting element 220 in an airtight sealed space.

[0091] Lid portion 213 has a light-transmitting region that transmits light reflected upward by the light-reflecting surface of reflecting member 240 and emits it to the outside. In other words, light reflected from the light-reflecting surface of reflecting member 240 toward lid portion 213 passes through the light-transmitting region of lid portion 213 and is emitted to the outside of light emitting device 200. The entire lid portion 213 may be a light-transmitting region. It is preferable that the light-transmitting region of lid portion 213 transmits 70% or more of the light reflected from the light-reflecting surface of reflecting member 240 toward lid portion 213.

[0092] The light emitting device 200 can be used, for example, in an in-vehicle headlight, but is not limited to this, and can also be used as a light source for lighting, a projector, a head-mounted display, a backlight for other displays, and the like.

[0093] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0094] In addition to the above-described embodiments, the following supplementary notes are also disclosed. [Appendix 1] The supporters and a first graphite layer disposed on the support layer; and a first metal layer disposed on the first graphite layer; a second metal layer disposed on the first metal layer; the first metal layer is thicker than the second metal layer; a first region in which the first metal layer is not disposed is provided in an outer periphery of the top surface of the first graphite layer; The second metal layer covers the first metal layer and the first region on the top surface of the first graphite layer. [Appendix 2] 2. The submount of claim 1, wherein the sides of the first graphite layer are not covered by the first metal layer and the second metal layer. [Appendix 3] the first graphite layer has a rectangular shape having long sides and short sides in a top view, 3. The submount according to claim 1, wherein the first region is provided along at least the short side. [Appendix 4] 4. The submount according to claim 1, wherein the first region is annularly provided on the outer periphery of the top surface of the first graphite layer. [Appendix 5] 5. The submount of claim 1, wherein, in a top view, at least a portion of the outer edge of the upper surface of the support layer coincides with the outer edge of the first graphite layer. [Appendix 6] 6. The submount of any one of claims 1 to 5, further comprising a third metal layer disposed on the second metal layer. [Appendix 7] the support layer is made of ceramic; the first metal layer comprises copper; 7. The submount of any one of claims 1 to 6, wherein the second metal layer comprises gold. [Appendix 8] a second graphite layer disposed below the support layer; and a fourth metal layer disposed below the second graphite layer; and a fifth metal layer disposed below the fourth metal layer; the fourth metal layer is thicker than the fifth metal layer; a second region in which the fourth metal layer is not disposed is provided in an outer periphery of the lower surface of the second graphite layer; 8. The submount of claim 1, wherein the fifth metal layer covers the fourth metal layer and the second region on the lower surface of the second graphite layer. [Appendix 9] the first metal layer and the fourth metal layer are made of the same metal material, 9. The submount of claim 8, wherein the second metal layer and the fifth metal layer are made of the same metal material. [Appendix 10] A base and a submount according to any one of Supplementary Notes 1 to 9 disposed on the base; and a light-emitting element disposed on the second metal layer. [Appendix 11] the light emitting element is an edge-emitting laser, 11. The light emitting device according to claim 10, wherein the first region is provided at least in a direction in which the edge-emitting laser emits light. [Appendix 12] providing a laminate having a support layer and a first graphite layer disposed on the support layer; disposing a first metal layer on the first graphite layer; removing a portion of the first metal layer to form a first groove portion that does not cover the first graphite layer; disposing a second metal layer thinner than the first metal layer on the first metal layer and on the first graphite layer in the first groove portion that is not covered by the first metal layer; cutting the second metal layer and the laminate along the first groove portion. [Appendix 13] In the step of preparing the laminate, the laminate further includes a second graphite layer disposed below the support layer; Prior to the cutting step, disposing a fourth metal layer beneath the second graphite layer; removing a portion of the fourth metal layer to form a second groove portion that is not covered by the second graphite layer at a position that overlaps with the first groove portion when viewed from the top surface side of the first metal layer; and disposing a fifth metal layer thinner than the fourth metal layer below the fourth metal layer and below the second graphite layer in the second groove portion that is not covered by the fourth metal layer, In the cutting step, 13. The method for manufacturing a submount described in claim 12, wherein the second metal layer, the stack, and the fifth metal layer are cut along the first groove portion and the second groove portion. [Explanation of symbols]

[0095] 10 Submount 11 Support layer 11a Top side 11b Bottom side 11c side 12 First graphite layer 12a Top side 12b Bottom side 12c side 12g graphene 13 1st metal layer 13x 1st groove 14 Second metal layer 15 Third metal layer 22 Second graphite layer 22a Top side 22b Bottom side 22c side 23 4th metal layer 23x 2nd groove 24 5th metal layer 100 laminate 200 Light-emitting device 211 Base 211a Top side 212 Frame 212a Top 212e,212f Step surface 213 Lid 214 Joint 215 Metal Film 220 Light-emitting element 220a Output end face 221 Metal Film 240 Reflective material 270 Wiring

Claims

1. The supporters and a first graphite layer disposed on the support layer; a first metal layer disposed on the first graphite layer; a second metal layer disposed on the first metal layer; the first metal layer is thicker than the second metal layer; a first region in which the first metal layer is not disposed is provided in an outer periphery of the top surface of the first graphite layer; The second metal layer covers the first metal layer and the first region on the top surface of the first graphite layer.

2. The submount of claim 1 , wherein the first graphite layer has sides that are not covered by the first metal layer and the second metal layer.

3. the first graphite layer has a rectangular shape having long sides and short sides in a top view, The submount according to claim 1 , wherein the first region is provided along at least the short side.

4. 3. The submount according to claim 1, wherein the first region is provided in an annular shape on the outer periphery of the top surface of the first graphite layer.

5. The submount according to claim 1 , wherein, in a top view, at least a portion of an outer edge of the upper surface of the support layer coincides with an outer edge of the first graphite layer.

6. The submount of claim 1 or 2, further comprising a third metal layer disposed on the second metal layer.

7. the support layer is made of ceramic; the first metal layer includes copper; The submount of claim 1 or 2, wherein the second metal layer comprises gold.

8. a second graphite layer disposed below the support layer; and a fourth metal layer disposed below the second graphite layer; a fifth metal layer disposed below the fourth metal layer; the fourth metal layer is thicker than the fifth metal layer; a second region in which the fourth metal layer is not disposed is provided in an outer periphery of the lower surface of the second graphite layer; The submount of claim 1 or 2, wherein the fifth metal layer covers the fourth metal layer and the second region on the lower surface of the second graphite layer.

9. the first metal layer and the fourth metal layer are made of the same metal material, The submount of claim 8 , wherein the second metal layer and the fifth metal layer are made of the same metal material.

10. A base and The submount according to claim 1 or 2, which is disposed on the base; and a light-emitting element disposed on the second metal layer.

11. the light emitting element is an edge-emitting laser, The light emitting device according to claim 10 , wherein the first region is provided at least in a direction in which the edge-emitting laser emits light.

12. providing a laminate having a support layer and a first graphite layer disposed on the support layer; disposing a first metal layer on the first graphite layer; removing a portion of the first metal layer to form a first groove portion that does not cover the first graphite layer; disposing a second metal layer thinner than the first metal layer on the first metal layer and on the first graphite layer in the first groove portion that is not covered by the first metal layer; cutting the second metal layer and the laminate along the first groove portion.

13. In the step of preparing the laminate, the laminate further includes a second graphite layer disposed below the support layer; Prior to the cutting step, disposing a fourth metal layer beneath the second graphite layer; removing a portion of the fourth metal layer to form a second groove portion that is not covered by the second graphite layer at a position that overlaps the first groove portion when viewed from the top surface side of the first metal layer; and disposing a fifth metal layer thinner than the fourth metal layer below the fourth metal layer and below the second graphite layer in the second groove portion that is not covered by the fourth metal layer, In the cutting step, The method for manufacturing a submount according to claim 12 , further comprising cutting the second metal layer, the stacked body, and the fifth metal layer along the first groove and the second groove.

Images