JP2014139979A - LED device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED device easy to manufacture and capable of being mounted efficiently.SOLUTION: An LED die 16 included in an LED device 10 is composed of a semiconductor layer 14 and a sapphire substrate 13 laminated together, with an external connection electrode 15 for a cathode and an anode being provided one each on the semiconductor layer 14 side. This LED die 16 is disposed in array form so as to fasten the sapphire substrate 13 to the underside of a phosphor sheet 11. Further, a white reflection member 12 is filled in a gap between the LED dies 16 adjacent to each other. Because there are only two pieces of the external connection electrode 15, each external connection electrode 15 can come in a relatively large size, and a pitch between themselves will be relatively large. This LED device 10 can be mounted on a mother board at a time, so that efficient mounting can be achieved.

Description

  The present invention relates to an LED device including a plurality of LED dies in one package.

  With the increase in brightness, the LED die, which is a bare chip, has also increased in size and has become available in the order of 1 mm × (0.5-1) mm. Since this size is almost the same as that of other chip components such as resistors, the planar size of the LED device in which the LED die is packaged with a resin or the like may be made the same size as the LED die. This package is called a chip size package (hereinafter referred to as CSP) because it directly reflects the size of the LED die. CSP not only requires a small mounting area and requires fewer packaging members, but also allows the number of components mounted on the mother board to be easily changed according to the required brightness, so that the degree of freedom in designing lighting devices and the like There is a feature that increases.

  As an ultimate CSP, an LED device is known in which the chip size of an LED die matches the outer shape of a package (for example, FIG. 6 of Patent Document 1). Therefore, FIG. 6A of Patent Document 1 is shown again in FIG. 9, and this LED device will be described. FIG. 9 is a cross-sectional view of a CSP-type light emitting device 6 (LED device) shown as a first conventional example. Note that some symbols are changed. A phosphor layer 30 and a lens 32 are laminated on the upper surface of the laminated body 12c (semiconductor layer). Under the laminated body 12c, there are seed metals 22a and 22b, copper wiring layers 24a and 24b, and columnar copper pillars 26a and 26b formed by electrolytic plating.

  The stacked body 12c includes a p-type cladding layer 12a, a light emitting layer 12e, and an n-type cladding layer 12b. The lower surface of the laminated body 12c is covered with an insulating layer 20 that is partially opened. Solder balls 36a and 36b are attached to the lower portions of the copper pillars 26a and 26b. A reinforcing resin 28 is filled between the copper pillars 26a and 26b.

  The planar size of the LED device 6 shown in FIG. 9 matches the planar size of the stacked body 12c. The LED device 6 is obtained by dividing a wafer in which the LED devices 6 are arranged and connected, and is called WLP (wafer level package) because it is the smallest in the product group divided by CSP. is there. Since the LED device 6 has a transparent insulating substrate (see paragraph 0021 of Patent Document 1 and FIG. 2) originally formed on the laminate 12c, the light from the light emitting layer 12e is upward (indicated by an arrow in the figure). (Only shown) For this reason, the phosphor layer 30 may be provided only on the LED device 6.

  Since the LED device 6 shown in FIG. 9 has the transparent insulating substrate cut to an extremely thin thickness as described above, the manufacturing apparatus becomes large and the manufacturing process becomes long. Moreover, since the LED device 6 forms the phosphor layer 30 at the wafer level, it cannot cope with variations in light emission characteristics of individual LED dies on the wafer. As a result, there is a problem that it becomes difficult to manage the emission color. Therefore, the inventor of the present application leaves a transparent insulating substrate as an LED device that is small but easy to make and easy to control the emission color, and the side surface of the transparent insulating substrate is white reflecting member along with the side surface of the semiconductor layer formed on the lower surface thereof. The LED device for flip chip mounting was manufactured by covering the upper surface of the transparent insulating substrate and the white reflective member with a phosphor sheet (FIG. 1 of Patent Document 2).

The LED device shown in FIG. 1 of Patent Document 2 is shown again in FIG. 10 and its structure will be described. FIG. 10 is a cross-sectional view of an LED device 10b shown as a second conventional example. In FIG. 10, the reference numerals are changed. The LED device 10b includes an LED die 16b having a sapphire substrate 14b (transparent insulating substrate) and a semiconductor layer 15b formed on the lower surface thereof. The LED device 10b includes a white reflecting member 17b on a side surface, and the LED die 16b and the white reflecting member 17b. A phosphor sheet 11b that converts the wavelength of the emitted light is provided on the upper surface. There is an adhesive layer 13b between the phosphor sheet 11b and the sapphire substrate 14b, and the phosphor sheet 11b and the sapphire substrate 14b are adhered to each other. The protruding electrodes 18b and 19b connected to the semiconductor layer 15b of the LED die 16b are an anode and a cathode, respectively, and are external connection electrodes for connecting to the mother substrate. The mother board is a board on which the LED device 10b is mounted together with other electronic components such as resistors and capacitors. Further, since the white reflecting member 17b functions sufficiently even when the thickness is 100 μm or less, the LED device 10b can be downsized. Furthermore, the LED device 10b is easy to manufacture because a so-called collective construction method can be applied in which a large number of LED devices are processed and finally a desired LED device is obtained by dividing the connected body into individual pieces.

JP 2010-141176 A (FIG. 6A) JP2012-227470A (FIG. 1)

  The inventor of the present application tried to apply the LED device 10b to a light source of a high-intensity lamp. The light source of this high-intensity lamp is mounted by arranging a large number of LED devices 10b on a substrate having good surface reflectance and heat dissipation efficiency. However, since the number of LED devices 10b is large, the problem of increasing the man-hours required for mounting has been faced.

  Therefore, the present invention has been made in view of this problem, and an object thereof is to provide an LED device that can be efficiently mounted while maintaining the feature of being easily manufactured.

In order to achieve the above object, the LED device of the present invention is an LED device including a plurality of LED dies in one package.
The LED die is formed by laminating a semiconductor layer and a transparent insulating substrate, and has one external connection electrode for each of an anode and a cathode on the semiconductor layer side,
The LED dies are arranged so that a plurality of the transparent insulating substrates are attached to the lower surface of the translucent sheet,
A filling member is provided in a gap between the LED dies adjacent to each other on the lower surface of the translucent sheet.

  The LED device of the present invention comprises a translucent sheet, an LED die provided with an external connection electrode, and a filling member that exists in the gap between the LED dies and maintains a flat plate shape, and has a simple structure with few constituent members. Therefore, it is easy to manufacture.

  The LED die included in the LED device of the present invention is a laminate of a semiconductor layer and a transparent insulating substrate, and is arranged so that the transparent insulating substrate is attached to the lower surface of the translucent sheet. One external connection electrode for the anode and one for the cathode is provided on the semiconductor layer side of the LED die. Since these external connection electrodes are concentrated in two, a relatively large size can be secured. For this reason, when the LED dies are arranged on the translucent sheet, each external connection electrode has a size that is easy to mount as described above and is arranged at a relatively large pitch. It becomes easy to mount. The LED device of the present invention having such an electrode configuration can be mounted efficiently because a large number of LED dies can be mounted once on a mother substrate or the like.

  The filling member may be a white reflecting member.

  The filling member may cover the bottom surface of the LED die except for the external connection electrode.

  The filling member may include a translucent member and a white reflective member, the side surface of the LED die may be covered with the translucent member, and the outer periphery of the translucent member may be covered with the white reflective member.

  You may provide the wiring which connects the external connection electrodes of two said LED dies on the bottom face.

  The translucent sheet may be a phosphor sheet.

  As described above, the LED device of the present invention is a simple one in which the LED dies are integrally arranged so that the transparent insulating substrate adheres to the lower surface of the translucent sheet, and the filling member is provided between the LED dies. It is easy to manufacture because of its structure. Furthermore, the LED device according to the present invention is easy to mount because each external connection electrode of the LED die is easy to mount and has a relatively large arrangement pitch. Therefore, the number of man-hours required for mounting is reduced and efficient mounting is achieved.

The top view of the LED device in 1st Embodiment of this invention. The front view of the LED apparatus shown in FIG. The bottom view of the LED device shown in FIG. Sectional drawing of the LED apparatus shown in FIG. The bottom view of the LED apparatus in 2nd Embodiment of this invention. Sectional drawing of the LED apparatus shown in FIG. The bottom view of the LED apparatus in 3rd Embodiment of this invention. Sectional drawing of the LED apparatus shown in FIG. Sectional drawing of the LED apparatus in a 1st prior art example. Sectional drawing of the LED apparatus in a 2nd prior art example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted. For the sake of explanation, the scale of the members is changed as appropriate. Furthermore, the relationship with the invention specific matter described in the claims is described in parentheses.

(First embodiment)
The LED device 10 shown as the first embodiment of the present invention will be described in detail with reference to FIGS. First, the external appearance of the LED device 10 will be described with reference to FIGS. 1 is a plan view of the LED device 10, FIG. 2 is a front view, and FIG. 3 is a bottom view. As shown in FIG. 1, when the LED device 10 is viewed from above, a rectangular phosphor sheet 11 (translucent sheet) can be seen. As shown in FIG. 2, when the LED device 10 is viewed from the front, the white reflecting member 12 (filling member) can be seen below the phosphor sheet 11, and the two external connection electrodes 15 are further under the white reflecting member 12. appear. As shown in FIG. 3, when the LED device 10 is viewed from below, the rectangular white reflecting member 12 and the semiconductor layer 14 of the LED die 16 (see FIG. 4) arranged in 5 rows and 5 columns inside can be seen. Two external connection electrodes 15 are provided inside each semiconductor layer 14.

Next, the internal structure of the LED device 10 will be described with reference to FIG. FIG. 4 is a cross-sectional view of the LED device 10 drawn along the line AA in FIG. In the LED device 10, the LED die 16 is attached to the lower surface of the phosphor sheet 11 via an adhesive layer (not shown), and the white reflecting member 12 exists in the gap between the LED dies 16 and the outer periphery of the LED device 10. To do. The LED die 16 includes a sapphire substrate 13 (transparent insulating substrate) and a semiconductor layer 14, a semiconductor layer 14 is formed on the lower surface side of the sapphire substrate 13, and two external connection electrodes 15 are connected to the semiconductor layer 14. .

  The phosphor sheet 11 is a translucent sheet obtained by curing a silicone resin kneaded with phosphor fine particles into a sheet shape, and has a thickness of about 100 to 300 μm. When it is desired to reduce loss due to concentration quenching, the phosphor sheet 11 is set to be thicker. The white reflecting member 12 is obtained by kneading and thermosetting reflective fine particles such as titanium oxide and alumina in a silicone resin. As a result, for example, in the case of the LED die 16 having a plane size of 0.8 mm × 0.3 mm, the arrangement pitch of the LED dies 16 can be 1.0 mm in the longitudinal direction and 0.5 mm in the short direction. At this time, the size of the external connection electrode 15 is about 0.3 mm × 0.2 mm, and solder reflow can be applied to the connection to the mother substrate or the like.

  The sapphire substrate 13 included in the LED die 16 has a thickness of about 80 to 150 μm. The semiconductor layer 14 formed on the lower surface of the sapphire substrate 13 has a thickness of about 10 μm, includes a p-type semiconductor layer and an n-type semiconductor layer, and a boundary surface thereof serves as a light emitting layer. An interlayer insulating film and a protective film exist below the semiconductor layer 14, and the external connection electrode 15 is formed on the protective film. The two external connection electrodes 15 are an anode and a cathode, and are connected to the p-type semiconductor layer and the n-type semiconductor layer via wiring on the interlayer insulating film, respectively. The external connection electrode 15 is an electrode for connecting to a mother board on which other electronic components such as a resistor and a capacitor are mounted, has a thickness of several hundreds of nanometers to several tens of micrometers, and has a gold layer or a surface on the surface for soldering. It has a tin layer.

  Next, a method for manufacturing the LED device 10 will be described. This manufacturing process is a so-called assembly method, in which a large number of LED dies 16 are arranged at a predetermined pitch on a supporting large-format phosphor sheet, and various processes are applied to the assembly. The aggregate is separated into pieces to obtain individual LED devices 10. In addition, several hundred to several thousand LED dies 16 are arranged on the large-sized phosphor sheet.

  First, a large number of LED dies 16 are arranged on a large-format phosphor sheet. At this time, the sapphire substrate 13 is stuck on the large-sized phosphor sheet with the external connection electrode 15 of the LED die 16 facing upward. The LED dies 16 may be arranged one by one on a large phosphor sheet with a picker or the like. It is also possible to arrange a plurality of LED dies 16 once in another pressure-sensitive adhesive sheet and affix the plurality of LED dies 16 to a large-sized phosphor sheet at once. Note that an adhesive is printed on the large-sized phosphor sheet in advance.

  Next, the white reflective member 12 before curing is filled between the LED dies 16 by a dispenser. At this time, a dam material is previously provided on the outer periphery of the large-sized phosphor sheet. When filling is completed, the white reflecting member 12 is cured by heating. Finally, the large-sized phosphor sheet is cut together with the white reflecting member 12 to obtain the LED device 10 which is divided into pieces. Dicer or wire is used for cutting. The white reflecting member 12 can be sufficiently shielded if it has a thickness of 30 to 50 μm when completed.

  In the LED device 10 of the present embodiment, the LED dies 16 are arranged in a rectangular area (see FIG. 3). However, the area to be arranged is not limited to a rectangle. For example, the LED dies 16 may be arranged in a circular area. Further, the phosphor sheet can be cut out in a circular shape to obtain an LED device having a circular planar shape. The LED dies 16 may be arranged radially. When the light emitting area of the LED device is circular, the light distribution can be easily adjusted by the lens. If it is not necessary to convert the wavelength of the light emitted from the LED die 16, the phosphor sheet 11 can be replaced with a transparent light-transmitting sheet.

(Second Embodiment)
In the LED device 10 shown in FIGS. 1 to 4, the white reflective member 12 is filled in the gap between the LED dies 16. However, the member filled between the LED dies 16 is not limited to the white reflecting member only for ensuring the mechanical strength, and may be a translucent member, for example. Further, as will be described later, the luminous efficiency is improved when the side surface of the LED die 16 is covered with a translucent member. Further, although the external connection electrode 15 and the semiconductor layer 14 are exposed on the bottom surface of the LED device 10, only the external connection electrode 15 may be exposed. In the LED device 10, the external connection electrodes 15 of the LED dies 16 are separated. However, wiring may be added on the bottom surface to connect the external connection electrodes 15 of the different LED dies 16.

  Therefore, as shown in FIGS. 5 and 6, as a second embodiment, the filling member includes a translucent member and a white reflective member, the bottom surface is covered with the white reflective member except for the external connection electrodes, and wiring that connects between the external connection electrodes is provided. The LED device 50 provided will be described.

  FIG. 5 is a bottom view of the LED device 50. Since the plan view is the same as FIG. 1 of the first embodiment, it is not shown. The front view is the same as FIG. 2 of the first embodiment except for the vicinity of the external connection electrode 15 (see FIG. 6) on the bottom surface, and is not shown because there is a sectional view (FIG. 6). In FIG. 5, when the LED device 50 is viewed from below, wirings 51 a, 51 b, 51 c, 51 d can be seen on the white reflective member 52. The wiring 51a and the wiring 51d are electrodes for supplying power, and are connected to one external connection electrode 15 (see FIG. 6) of the LED die 16 at the upper left corner and the lower right corner of the drawing. The wiring 51b connects the external connection electrodes 15 of the LED die 16 adjacent in the longitudinal direction (left-right direction) in the figure. The wiring 51c connects the external connection electrodes 15 of the LED die 16 adjacent in the short direction (vertical direction) in the figure. Thus, in the LED device 50, 25 LED dies 16 are connected in series. In the figure, the LED die 16 covered with the white reflecting member 52 is indicated by a dotted line.

  Next, the internal structure of the LED device 50 will be described with reference to FIG. FIG. 6 is a cross-sectional view of the LED device 50 drawn along the line BB in FIG. In the LED device 50, the LED die 16 is attached to the lower surface of the phosphor sheet 11 via an adhesive layer (not shown). The side surface of each LED die 16 is covered with a fluorescent resin 53 (translucent member), and the white reflecting member 52 exists in the gap between the fluorescent resin 53, the outer peripheral portion of the LED device 50, and the bottom surface portion of the LED die 16. The LED die 16 is the same as the LED die 16 of the LED device 10 shown in FIG. The external connection electrode 15 of each LED die 16 is exposed from the white reflecting member 52, and wirings 51 a, 51 b, 51 c are connected to the external connection electrode 15. The fluorescent resin 53 is obtained by kneading and curing phosphor fine particles in a silicone resin, and has a thickness of about 50 μm.

  As described above, the LED device 50 includes the fluorescent resin 53 between the side surface of the LED die 16 and the white reflecting member 52. After the LED die 16 is arranged on a large-format phosphor sheet (see the manufacturing method for the LED device 10 of the first embodiment), the LED device 50 fills the gap between the LED die 16 with the fluorescent resin 53 and cures it. Then, the fluorescent resin 53 is scraped to form a groove so that the fluorescent resin 53 remains on the side of the LED die 16, and then the white reflecting member 52 before curing is filled and cured in this groove, and finally is separated into pieces. To manufacture.

In the LED device 10 of the first embodiment shown in FIG. 4 and the like, the side surface of the LED die 16 and the white reflecting member 12 are in direct contact with each other, so that light that is going to be emitted from the side surface of the sapphire substrate 13 is sapphire substrate. 13 is returned. This light becomes stray light or attenuates due to reflection or reabsorption by the semiconductor layer 14. That is, the LED device 10 includes such a loss due to its structure. On the other hand, when the fluorescent resin 53 is present between the side surface of the LED die 16 and the white reflecting member 52 as in the LED device 50 of the present embodiment, the light is emitted from the side surface of the LED die 16,
Even though a part of the light reflected by the white reflecting member 12 through the fluorescent resin 53 enters the sapphire substrate 13 again, most of the light propagates through the fluorescent resin 53 and is emitted from the LED device 50. Loss is reduced and the emission efficiency is improved.

  In the LED device 50, the white reflecting member 52 covers the bottom surface (semiconductor layer 14) of the LED die 16 except for the external connection electrodes 15. When filling the white reflective member 52 before curing, the LED device 50 fills the white reflective member 52 in a large amount, and after the white reflective member 52 is cured, the white reflective member 52 is polished to expose the external connection electrodes 15. Can be manufactured. At this time, a squeegee can be used for filling the white reflecting member 52. When the white reflecting member 52 is present on the bottom surface of the LED die 16, the semiconductor layer 14 can be protected from contamination of the bottom surface, and light that is about to leak from the bottom surface of the semiconductor layer 14 can be shielded from the bottom surface of the LED device 50. .

  The wirings 51a to 51d formed on the bottom are formed by a printing method or a plating method combined with photolithography. At this time, a material that does not melt at the reflow temperature when the LED device 50 is mounted on a mother board or the like is selected for the wirings 51a to 51d. Since the LED device 50 only needs to be electrically connected to the electrodes of the mother board and the wirings 51a and 51d, the mounting is greatly simplified as compared with the LED device 10 of the first embodiment.

  In the LED device 50, the filling member is composed of the fluorescent resin 53 and the white reflecting member 52. However, the filling member may be only a translucent member such as the fluorescent resin 53 or the transparent resin. In this case, as described above, the light emitted from the side portion of the LED die 16 is improved in luminous efficiency because many components do not return into the LED die 16. Further, when the bottom surface is covered with a light-transmitting member such as a fluorescent resin 53 or a transparent resin, contamination of the semiconductor layer 14 can be prevented even if light leaking from the bottom surface of the LED die 16 cannot be blocked. Further, in the LED device 50, the white reflecting member 52 has a mesh shape when viewed in plan. On the other hand, the white reflective member may surround only the outer peripheral portion of the LED device 50 on the frame. This simplifies the process of cutting the translucent member to form the groove.

(Third embodiment)
The LED dies 16 included in the LED devices 10 and 50 shown in the first and second embodiments are separated one by one. However, in the LED device of the present invention, it may be better to arrange the LED dies 16 in a connected state. 7 and 8, an LED device 70 in which two LED dies 16 connected elements are arranged on a phosphor sheet will be described as a third embodiment.

  FIG. 7 is a bottom view of the LED device 70. The plan view only shows a rectangular phosphor sheet, and the front view is not shown because it can be easily inferred from the cross-sectional view. In FIG. 7, when the LED device 70 is viewed from below, the semiconductor layer 14 of the LED die 16 can be seen inside the white reflecting member 72. Here, the LED die 16 is the same as the LED die 16 shown in FIG. 4 or the like, but is cut from the wafer in a state where two are connected. If it does in this way, the man-hour concerning the arrangement | positioning to the dicing of a wafer and the large format fluorescent substance sheet (refer to the manufacturing method with respect to LED device 10 of 1st Embodiment) can be reduced. Each LED die 16 has two external connection electrodes 15. In this embodiment, the LED dies arranged on the phosphor sheet 71 (see FIG. 8) are elements cut out from the wafer in a state where the two LED dies 16 are connected, and are not separated. 7, lines between the LED dies 16 are added (the same applies to FIG. 8).

Next, the internal structure of the LED device 70 will be described with reference to FIG. FIG. 8 is a cross-sectional view of the LED device 70 drawn along the CC line of FIG. The cross section of the LED device 70 and the cross section of the LED device 10 shown in FIG. 4 are substantially the same, and the place where the LED die 16 is connected in the cross section of the LED device 70 is different. Note that the number of LED dies 16 included in the cross-sectional views of FIG. 4 and FIG. The phosphor sheet 11 and the white reflecting member 12 in FIG. 4 and the phosphor sheet 71 and the white reflecting member 72 in FIG. 8 are made of the same material.

  The LED device 70 is a line light source used in a tubular lighting device or the like. For this reason, two LED dies 16 were connected in the longitudinal direction. Further, like the LED device 50 of the second embodiment, the bottom surface of the LED die 16 is covered with the white reflecting member 72, the filling member is made of the translucent member and the white reflecting member 72, or the bottom portion is wired. It may be formed.

10, 50, 70 ... LED device,
11, 71 ... phosphor sheet (translucent sheet),
12, 52, 72 ... white reflective member,
13: Sapphire substrate (transparent insulating substrate),
14 Semiconductor layer,
15 ... External connection electrode,
16 ... LED die,
51a, 51b, 51c, 51d... Wiring.

Claims (6)

In an LED device including a plurality of LED dies in one package,
The LED die is formed by laminating a semiconductor layer and a transparent insulating substrate, and has one external connection electrode for each of an anode and a cathode on the semiconductor layer side,
The LED dies are arranged so that a plurality of the transparent insulating substrates are attached to the lower surface of the translucent sheet,
An LED device comprising a filling member in a gap between the LED dies adjacent to each other on the lower surface of the translucent sheet.   The LED device according to claim 1, wherein the filling member is a white reflecting member.   The LED device according to claim 1, wherein the filling member covers a bottom surface of the LED die except for the external connection electrode.   The filling member includes a translucent member and a white reflective member, the translucent member covers the side surface of the LED die, and the white reflective member covers the outer periphery of the translucent member. The LED device according to claim 1 or 3, characterized in that   5. The LED device according to claim 1, further comprising a wiring for connecting external connection electrodes of the two LED dies on the bottom surface. 6.   The LED device according to claim 1, wherein the translucent sheet is a phosphor sheet.

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