Wiring board and LED module

Abstract

To provide a wiring board and an LED module that can increase the amount of light emitted to the outside.SOLUTION: A wiring board comprises a substrate which has a first surface and a second surface located on the opposite side from the first surface, an aluminum layer located above the first surface, and one or more first metal films located above the aluminum film, and the first metal films include an electrode film where a light-emitting element is mounted.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a wiring board and an LED (Light Emitting Diode) module. [Background technology]

[0002] Patent Document 1 describes a wiring board that aims to effectively dissipate heat and increase the amount of light emitted in an LED module. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-177445 Summary of the Invention [Problem to be solved by the invention]

[0004] The wiring board of an LED module has long had the function of reflecting light to increase the amount of light emitted to the outside. The present disclosure aims to provide a wiring board and an LED module that can further increase the amount of light emitted to the outside. [Means for solving the problem]

[0005] The wiring board according to the present disclosure includes: a substrate having a first surface and a second surface opposite the first surface; an aluminum film located above the first surface; one or more metal films located above the aluminum film; Equipped with The metal film includes an electrode film on which a light emitting element is mounted.

[0006] The LED module according to the present disclosure comprises: The above wiring board; an LED mounted on the wiring board; Equipped with. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a wiring board and an LED module that can further increase the amount of light emitted to the outside. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a plan view illustrating a wiring substrate according to an embodiment of the present disclosure. [Figure 2] 1A is a longitudinal cross-sectional view showing an LED module according to an embodiment of the present disclosure, and FIG. 1B is an enlarged view of a portion C1. [Figure 3] 1 is a graph showing the relationship between the wavelength of light and the reflectance of various metal films. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following, the up and down directions may be indicated when describing each part. Up refers to a direction perpendicular to the first surface S11a of the substrate 11 and facing from the second surface S11b toward the first surface S11a. This direction may be different from the direction when the wiring substrate 10 and the LED (Light Emitting Diode) module 100 are in use. In the description, the term "'metal name' + 'film'" refers to a film in which the metal of the metal name is the main component. A main component means a component that accounts for 80% or more by mass. In the description, When we say planar perspective, we mean looking from above.

[0010] Fig. 1 is a plan view showing a wiring board 10 according to an embodiment of the present disclosure. Fig. 2 is a longitudinal cross-sectional view (A) showing an LED module 100 according to an embodiment of the present disclosure, and an enlarged view (B) of a portion C1. Fig. 2(A) shows the longitudinal cross-section of the wiring board 10 taken along line AA in Fig. 1.

[0011] The wiring board 10 according to the embodiment of the present disclosure may be a substrate on which a light emitting element 110 is mounted. The wiring board 10 may include a substrate 11 that is an insulator. The substrate 11 may have a first surface S11a that is an upper surface and a second surface S11b that is a lower surface. The substrate 11 may be a ceramic primarily composed of aluminum nitride (AlN) or silicon nitride (Si3N4).

[0012] The wiring substrate 10 may further include an aluminum film 12 located above the first surface S11a, one or more first metal films 13 located above the aluminum film 12, and a second titanium film 14 located between the aluminum film 12 and the first surface S11a.

[0013] The wiring board 10 may further include via conductors 21 and inner layer conductors 22 located on the substrate 11, and a second metal film 15 located below the second surface S11b. The via conductors 21 and inner layer conductors 22 may be located from the first surface S11a to the second surface S11b, and may be configured to electrically connect the second metal film 15 on the second surface S11b side to the first metal film 13 on the first surface S11a side.

[0014] The first surface S11a of the substrate 11 may include a plurality of regions R1 and R2 (see FIGS. 1 and 2A), and the structure on the first surface S11a of the substrate 11 may be divided into a plurality of parts. The "structure on the first surface S11a" refers to the second titanium film 14, the aluminum film 12, and the first metal film 13. Each of the divided parts may be located in each of the plurality of regions R1 and R2. With this structure, the first metal film 13 located in region R1 and the first metal film 13 located in region R2 are not electrically connected at least on the first surface S11a.

[0015] The second surface S11b of the substrate 11 may include a plurality of regions R11 and R12, and the second metal film 15 below the second surface S11b may be divided into a plurality of parts, each of which may be located in one of the plurality of regions R11 and R12. With this configuration, the second metal film 15 located in the region R11 and the second metal film 15 located in the region R12 are not electrically connected at least below the second surface S11b.

[0016] The wiring board 10 may have a plurality of sets of via conductors 21 and inner layer conductors 22 along a plurality of wiring paths that are not conductive to one another. The set of via conductors 21 and inner layer conductors 22 along a first wiring path may provide electrical continuity between the first metal film 13 on the region R1 of the first surface S11a and the second metal film 15 below the region R11 of the second surface S11b. Similarly, the set of via conductors 21 and inner layer conductors 22 along a second wiring path may provide electrical continuity between the first metal film 13 on the region R2 of the first surface S11a and the second metal film 15 in the region R12 of the second surface S11b.

[0017] Via conductor 21 may be mainly composed of a high-melting point metal such as tungsten (W), and may be configured by co-firing via conductor 21 and substrate 11. A high-melting point metal means a metal with a melting point of 2000°C or higher.

[0018] The substrate 11 may have a laminated structure having multiple layers 11 a and 11 b. The substrate 11 may have a configuration in which multiple stacked green sheets are integrated by firing, and the multiple layers 11 a and 11 b may correspond to the layers of the multiple green sheets before firing.

[0019] The via conductors 21 are not linearly connected across the layers 11a and 11b, but are arranged in a straight line across the layers 11a and 11b. The via conductors 21 located on layers 11a and 11b may be positioned so as not to overlap when viewed from above, and the via conductors 21 located on layers 11a and 11b may be connected via inner layer conductors 22. With this configuration, even if voids occur between the via conductors 21 on layers 11a and 11b, the presence of the inner layer conductors 22 between the two via conductors 21 can prevent the voids from migrating from the first surface S11a to the second surface S11b. Therefore, when the upper part of the substrate 11 is sealed in an airtight space, or when the upper and lower parts of the substrate 11 are different spaces, the airtightness between the upper and lower spaces can be improved.

[0020] The aluminum film 12 may have a larger area than the electrode film 13a described below. That is, the aluminum film 12 may include a region R21 where the second metal film 15 is located and a region R22 where the second metal film 15 is not located. An aluminum oxide film 16 may be located in the region R22 above the aluminum film 12 where the second metal film 15 is not located.

[0021] <Details of the first metal film 13> 2(B), the plurality of first metal films 13 may include an electrode film 13a on which a light-emitting element is mounted, and a conductor film 13b located between the electrode film 13a and the aluminum film 12. The conductor film 13b may include a platinum (Pt) film 13b2 as a barrier layer located under the electrode film 13a, and a first titanium (Ti) film 13b1 as an adhesive layer located on the aluminum film 12. The electrode film 13a may be a gold (Au) film 13a1, or a film in which a gold-tin (AuSn) film 13a2 is located on the gold (Au) film 13a1.

[0022] <Details of the second metal film 15> The second metal film 15 located on the second surface S11b may be a film formed by stacking, from top to bottom, a titanium (Ti) film 15a, a nickel chromium (NiCr) film 15b, a gold (Au) film 15c, a nickel (Ni) film 15d, and a gold (Au) film 15e.

[0023] <Effects of the wiring board 10> As described above, the wiring board 10 of this embodiment includes the aluminum film 12 located above the first surface S11a of the substrate 11 and the first metal film 13 located above the aluminum film 12, and the first metal film 13 includes the electrode film 13a on which the light-emitting element 110 is mounted. Therefore, a portion of the output of the light-emitting element 110 can be reflected by the aluminum film 12 and sent outward. This increases the amount of light output from the light-emitting element 110 to the outside (upward in the example of FIG. 2(A)).

[0024] Furthermore, according to the wiring board 10 of this embodiment, the first metal film 13 includes an electrode film 13a and a conductor film 13b electrically connected to the electrode film 13a. The wiring board 10 further includes an aluminum oxide film 16 located above the aluminum film 12 in a region R22 where the electrode film 13a and the conductor film 13b are not located. Therefore, the aluminum film 12 extends to both the region R21 where the electrode film 13a and the conductor film 13b are located and the region R22 where they are not located, allowing for a larger area of ​​the aluminum film 12 to be used. This allows the aluminum film 12 to reflect the output of the light-emitting element 110 over a wider area. Furthermore, the aluminum oxide film 16 protects the aluminum film 12 in the region where the electrode film 13a and the conductor film 13b are not located. This allows the aluminum film 12 in the region R22 to maintain its aluminum metal properties for a long period of time. This reduces deterioration of the light reflection characteristics throughout the entire area of ​​the aluminum film 12, and maintains the effect of increasing the amount of light irradiated to the outside through reflection by the aluminum film 12 for a long period of time.

[0025] Furthermore, according to the wiring substrate 10 of this embodiment, the first metal film 13 includes a first titanium (Ti) film 13b1 located between the electrode film 13a and the aluminum film 12. 3b1 provides high bonding strength between the aluminum film 12 and the electrode film 13a, thereby improving the reliability of the wiring board 10.

[0026] Furthermore, according to the wiring board 10 of this embodiment, the aluminum film 12 is divided into multiple pieces on the first surface S11a, thereby reducing the possibility that multiple pairs of electrode films 13a or conductor films 13b that are not conductive with each other will become conductive through the aluminum film 12.

[0027] Furthermore, according to the wiring board 10 of this embodiment, the substrate 11 is made of ceramics and further includes a second titanium (Ti) film 14 located between the aluminum film 12 and the first surface S11a. The second titanium film 14 provides high bonding strength between the ceramic substrate 11 and the aluminum film 12. This improves the reliability of the wiring board 10.

[0028] Furthermore, according to the wiring board 10 of the present embodiment, the substrate 11 is made of ceramics, and aluminum nitride can be adopted as the main component. By adopting aluminum nitride, the heat dissipation property of the light-emitting element 110 can be improved.

[0029] Furthermore, according to the wiring board 10 of the present embodiment, since the via conductor 21 is provided across the first surface S11a to the second surface S11b within the substrate 11, the current necessary for driving the light-emitting element 110 can be supplied between the first surface S11a and the second surface S11b of the substrate 11 via the via conductor 21.

[0030] Furthermore, according to the wiring board 10 of the present embodiment, it further includes a second metal film 15 located below the second surface S11b. The wiring board 10 may further have an aluminum film located below the second surface S11b. The aluminum film may be joined to the second surface S11b via a titanium film, or the second metal film 15 may be located under the aluminum film. The light output from the light-emitting element 110 to the wiring board 10 side may pass through the substrate 11. The aluminum film below the second surface S11b reflects the light that has passed through the substrate 11 by the aluminum film on the second surface S11b at a location that does not overlap with the aluminum film 12 on the first surface S11a in a plan view, and the amount of light irradiated to the outside can be further increased.

[0031] <Configuration of LED Module> The LED module 100 according to the embodiment of the present disclosure may include a wiring board 10 and a light-emitting element 110 mounted on the wiring board 10. The light-emitting element 110 may be an LED. Furthermore, the light-emitting element 110 has two electrodes, and as shown in FIG. 2(A), it may be mounted on the wiring board 10 such that one electrode is joined to the electrode film 13a in the region R1 and the other electrode is joined to the electrode film 13a in the region R2. The above joining may be a joining via a conductive joining material such as solder. The LED module 一百 may have a configuration in which the configuration on the first surface S11a side of the substrate 11 including the light-emitting element 110 is sealed in an airtight space.

[0032] 2(A), in addition to the light output from the light-emitting element 110 to the outside of the module (e.g., upward), the LED module 100 also outputs light from the light-emitting element 110 toward the wiring substrate 10 by being reflected by the aluminum film 12. This makes it possible to realize an LED module 100 that emits a large amount of light to the outside. In FIG. 2(A), the light output from the light-emitting element 110 is represented by a thick chain line.

[0033] The light emitting element 110 may be an LED having a characteristic of mainly outputting light in the ultraviolet region. Mainly emitting light in a certain wavelength region means that the amount of light in that wavelength region is greater than the amount of light in other wavelength regions. The light output by the light emitting element 110 having the above characteristics may include visible light. Light in the ultraviolet region has high transparency through thin films and the like. Therefore, of the light output from the light emitting element 110 having the above characteristics, a relatively large proportion of the light is output to the wiring board 10 side. Therefore, by reflecting light through the aluminum film 12, the total amount of light output to the outside of the module can be further increased.

[0034] The light emitting element 110 may be an LED that mainly emits UV-C light. UV-C refers to light in the wavelength range of 200 nm to 280 nm. FIG. 3 is a graph showing the relationship between the wavelength of light and the reflectance of various metal films. In the graph, the UV-C wavelength range is indicated by shading. As shown in the graph, many objects have low reflectance of UV-C, but aluminum (Al) has high reflectance of UV-C.

[0035] Therefore, by having the aluminum film 12 on the wiring substrate 10 of the LED module 100, the light output toward the wiring substrate 10 side, among the UV-C light mainly output from the light emitting element 110, can be reflected toward the outside of the module by the aluminum film 12 with high reflectivity. As a result, the amount of UV-C light irradiated toward the outside of the module can be increased.

[0036] The above describes the embodiments of the present disclosure. However, the wiring board and LED module of the present disclosure are not limited to the above embodiments. The details shown in the embodiments can be modified as appropriate without departing from the spirit of the invention.

[0037] An embodiment of the present disclosure will be described below. (1) The wiring board is a substrate having a first surface and a second surface opposite the first surface; an aluminum film located above the first surface; one or more first metal films located above the aluminum film; Equipped with The first metal film includes an electrode film on which a light emitting element is mounted.

[0038] (2) The wiring board of (1) above is the first metal film includes the electrode film and a conductor film electrically connected to the electrode film, The semiconductor device further includes an aluminum oxide film located above the aluminum film in a region where the electrode film and the conductor film are not located.

[0039] (3) The wiring board of (1) or (2) above is The first metal film is A first titanium (Ti) film is included, the first titanium (Ti) film being located between the electrode film and the aluminum film.

[0040] (4) Any one of the wiring boards (1) to (3) above is The aluminum film is divided into a plurality of parts on the first surface.

[0041] (5) Any one of the wiring boards (1) to (4) above is the substrate is ceramic; A second titanium (Ti) film is provided between the aluminum film and the first surface.

[0042] (6) Any one of the wiring boards (1) to (5) above is The light emitting element mounted on the electrode film mainly emits light in the ultraviolet region.

[0043] (7) Any one of the wiring boards (1) to (6) above is The light emitting element mainly outputs UV-C.

[0044] (8) Any one of the wiring boards (1) to (7) above, the substrate is ceramic; The main component of the substrate is aluminum nitride.

[0045] (9) Any one of the wiring boards (1) to (8) above, a via conductor located in the substrate across from the first surface to the second surface, Prepare.

[0046] (10) Any one of the wiring boards (1) to (9) above, The semiconductor device further includes a second metal film located below the second surface.

[0047] In one embodiment, (11) The LED module is Any one of the wiring substrates (1) to (10) above; an LED mounted on the wiring board; Equipped with. [Explanation of symbols]

[0048] 10. Wiring board 11 Circuit Board S11a 1st page S11b 2nd side 12 Aluminum film R21, R22 area 13 First metal film 13a Electrode membrane 13a1 gold film 13a2 Gold-tin film 13b Conductor film 13b1 First titanium film 13b2 Platinum film 14 Second titanium film 15 Second metal film 15a Titanium film 15b Nickel chrome film 15c gold film 15d Nickel film 15e gold film 16 Aluminum oxide film 21 Via conductor 22 Inner layer conductor 100 LED modules 110 Light-emitting element

Claims

1. a substrate having a first surface and a second surface opposite the first surface; an aluminum film located above the first surface; one or more first metal films located above the aluminum film; Equipped with The first metal film includes an electrode film on which a light emitting element is mounted. Wiring board.

2. the first metal film includes the electrode film and a conductor film electrically connected to the electrode film, The semiconductor device further includes an aluminum oxide film located above the aluminum film in a region where the electrode film and the conductor film are not located. The wiring board according to claim 1.

3. The first metal film is a first titanium (Ti) film located between the electrode film and the aluminum film; The wiring board according to claim 1.

4. the aluminum film is divided into a plurality of pieces on the first surface; The wiring board according to claim 1.

5. the substrate is ceramic; a second titanium (Ti) film located between the aluminum film and the first surface; The wiring board according to claim 1.

6. The light-emitting element mounted on the electrode film mainly outputs light in the ultraviolet region. The wiring board according to claim 1.

7. The light-emitting element mainly outputs UV-C. The wiring board according to claim 6.

8. the substrate is ceramic; The main component of the substrate is aluminum nitride. The wiring board according to claim 1.

9. a via conductor located in the substrate across from the first surface to the second surface, Prepare, The wiring board according to claim 1.

10. further comprising a second metal film located below the second surface; The wiring board according to claim 1.

11. The wiring substrate according to any one of claims 1 to 10; an LED mounted on the wiring board; An LED module comprising:

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