JP3221345B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a plurality of LED chips mounted on a circuit board.

[0002]

2. Description of the Related Art Conventionally, LEDs have been used for applications such as indicators of electronic equipment. In recent years, LEDs whose luminous efficiency and luminance have been improved, and whose luminance per unit input is superior to incandescent lamps, have been developed. A device has been developed, and by integrating a plurality of the LED devices, application to lighting applications has become possible.

[0003] Further, since the LED element has a long service life, it has the merit of maintenance such as labor saving of replacing a lamp, and the narrow emission wavelength range does not emit infrared light which damages fresh food (for example, There is an advantage that it can be used as a showcase lighting for a fresh fish store), and that it can be used for lighting that does not emit ultraviolet light that discolors and degrades artworks (for example, lighting for museums and museums).

FIG. 5 shows an example of mounting a current LED element.
This will be described below. The surface of the electrode 11 of one LED chip 1 is fixed to the lead frame 2a by die bonding with a conductive adhesive, and the other electrode 12 of the LED chip 1 is wire bonded to the other lead frame 2b by a bonding wire 21. The lead frames 2a and 2b are connected to the PN electrodes of the diodes,
Power is supplied to the LED chip 1 via a and 2b. Further, the transparent sealing resin 22 is formed by molding.
Is molded into a lens shape to complete an individual LED element. The lead frames 2a and 2b of the individual LED elements completed in this way are mounted at predetermined positions on the substrate by soldering or the like. That is, separate bonding methods of bonding and wire bonding are used for the electrodes 11 and 12 on the lower surface and the upper surface of the LED chip 1.

[0005]

However, when the above-mentioned LED element is applied to the field of lighting, LE is required.
Since the brightness of each of the D elements is low, it is necessary to use a large number of LED elements, and the lead frames 2a and 2b of the plurality of LED elements are soldered to predetermined positions of a substrate on which a current supply circuit for each element is formed. It has to be implemented collectively by the method.

Therefore, when manufacturing a lighting device using the above-described LED elements, the electrodes 11 and 12 are connected to the lead frame 2a and the lead frame 2a by two bonding methods of element bonding and wire bonding at the stage of manufacturing the LED elements. 2b
And connecting the lead frames 2a and 2b of a plurality of LED elements to predetermined positions of the substrate by soldering or the like, which is inferior in productivity.

[0007] The present invention has been made in view of the above points, and an object of the present invention is to provide a semiconductor device in which a plurality of LED chips are mounted on a substrate and which has high productivity. It is in.

[0008]

According to the first aspect of the present invention,
A plurality of LED chips and a plurality of first recesses for accommodating each of the LED chips are formed, and light is emitted from a lower surface of the LED chip in a state where the LED chips are housed below the first recesses. A three-dimensional molded substrate having a second concave portion having a reflective wall for reflecting light in an upward direction, the wiring pattern being formed from two opposing side walls of the first concave portion to the upper surface; The LED chip is mounted such that the surface of the LED chip that is not the electrode surface is on the bottom surface side of the first recess, and the electrode surface faces the wiring pattern formed on the side wall. The connection is made by solder and the wiring pattern.

According to a second aspect of the present invention, in the first aspect of the present invention, solder plating is previously applied to the wiring pattern formed on the side wall, and the solder plating is melted.
By connecting the wiring pattern and the electrodes via the molten solder, the electrodes of adjacent LED chips are connected to each other.

According to a third aspect of the present invention, in the first aspect of the present invention, a solder foil is previously arranged on the wiring pattern formed on the side wall, and the solder foil is melted. By connecting the wiring pattern and the electrodes, the electrodes of adjacent LED chips are connected to each other.

According to a fourth aspect of the present invention, in the first to third aspects, the side wall and the bottom surface of the first recess form an obtuse angle.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, when the upper surface side of the LED chip is sealed with a resin, a transparent resin is injected and the lens is cured by heating. It is characterized in that it is formed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial plan view of a semiconductor device according to an example of an embodiment of the present invention, and FIG.
It is a schematic diagram which shows the cross section state in. Numeral 1 is a small LED chip of 0.3 mm 3 cubic formed by PN junctions.
12 are formed. 3 is a three-dimensional molded substrate (MID substrate: Molded Interconnection)
Device), a plurality of first recesses 31 for accommodating each LED chip 1 are provided, and a second recess 32 having an opening smaller than the recess 31 is continuously provided below each recess 31. The LED chip 1 has electrodes 11, 12
Is mounted such that the surface on which no is formed is on the bottom surface side of the concave portion 31. At this time, the opening of the concave portion 32 is formed smaller than the size of the bottom surface of the LED chip 1, and the peripheral portion of the bottom surface of the LED chip 1 is locked by the step 33 formed by the concave portion 31 and the concave portion 32. It has become. Therefore,
With the LED chip 1 housed in the recess 31, a gap is formed by the recess 32 in the lower portion of the bottom surface of the LED chip 1.

FIG. 2 is a schematic configuration diagram showing a state in which a plurality of LED chips 1 are mounted in a plurality of concave portions 31 of the MID substrate 3.

Recess 31 as mounting portion for LED chip 1
Is determined in relation to the dimensions of the LED chip 1. The side wall 34 facing the surface on which the electrodes 11 and 12 are not formed has an obtuse angle with respect to the bottom surface of the concave portion 31 so that the reflected wave from the LED chip 1 by the side wall 34 goes to the opening side of the concave portion 31. It is better to have a slope. The side wall 35 facing the surface on which the electrodes 11 and 12 are formed rises perpendicularly to the bottom surface of the recess 31.

On the upper surface of the MID substrate 3, a wiring pattern 4 made of copper for connecting the electrodes 11 and 12 of the adjacent LED chips 1 and supplying power to each of the LED chips 1 is formed. The wiring pattern 4 is the MID substrate 3
From the upper surface to the side wall 35 facing the surface on which the electrodes 11 and 12 are formed. Wiring pattern 4
Is a method of forming a copper pattern having a predetermined thickness (for example, 0.1 mm or less) by electroless plating.

Next, a solder 5 is formed on the wiring pattern 4 formed on the side wall 35 by plating. The thickness of the solder 5 is determined by calculating the amount of solder such that the LED chip 1 can be easily mounted in the concave portion 31 and the connection between the wiring pattern 4 and the electrodes 11 and 12 is reliably performed when the solder 5 is melted. I do.

A plurality of LED chips 1 are mounted in each of the recesses 31 of the MID substrate 3 in the above state, and are heated by reflow in an inert atmosphere such as nitrogen. By this reflow heating, solder 5
Is melted, and the wiring pattern 4 and the electrodes 11 and 12 are joined. Note that the reflow heating may be performed in an ordinary atmosphere, and in this case, a flux may be used to cope with solder oxidation. The solder 5 does not hinder the mounting of the LED chip 1 in the recess 31 of the MID substrate 3 in the state of being plated with solder, and fills the gap between the electrodes 11 and 12 and the side wall 35 after melting. It works to connect. In this manner, the mounting of the plurality of LED chips 1 on the MID substrate 3 is completed, and the fixing of the LED chips 1 into the recesses 31 and the electrodes 1 of the adjacent LED chips 1 are performed.
The electrical connection between 1 and 12 is made.

The solder 5 may be formed by a method other than plating, in which a ribbon-shaped solder foil cut to a predetermined length is housed at a position along the side wall 35 in the recess 31.

If the LED chip 1 is mounted on the step portion 33 of the concave portion 31 temporarily by an adhesive such as a UV adhesive or an instant curing type adhesive, the solder 5 by reflow heating can be used.
Can be prevented from shifting until the next step of melting.

According to the present embodiment, in a state where the plurality of LED chips 1 are mounted on the respective concave portions 31 of the MID substrate 3,
If the reflow heating is performed, the fixing of the LED chip 1 into the concave portion 31 and the electrical connection between the electrodes 11 and 12 of the adjacent LED chip 1 can be performed at a time. The manufacturing process can be simplified and the productivity can be improved as compared with a conventional semiconductor device that requires three steps of a connection step. In addition, since the joining process quality control requires only one process, stable yield can be expected. Furthermore, LED chip 1
When the LED chip 1 is housed in the concave portion 31, a gap is formed by the concave portion 32 below the bottom surface (lower surface) of the LED chip 1.
Since the light is reflected by the second reflecting wall 36 toward the upper surface of the MID substrate 3, the luminous efficiency can be improved.

FIG. 3 is a schematic view showing a partial cross section and a top view of a semiconductor device according to still another embodiment of the present invention. In the present embodiment, in the above embodiment,
The lens 6 is formed by dropping a transparent (light-transmissive and somewhat colored as necessary) sealing resin from above the concave portion 31 and heating and curing the resin. Here, the lens 6
Control of the discharge amount of the sealing resin and, as shown in FIG.
By changing the shape of 1, the desired light distribution characteristics can be realized. In the case of FIG. 4A, the planar shape of the concave portion 31 is a square, and a lens symmetric with respect to the XY axis is formed. In the case of FIG. 4B, the planar shape of the concave portion 31 is rectangular, and the XY direction is Unequal lenses can be formed, and in the case of FIG. 4C, a spherical lens can be formed by providing a circular counterbore 36 above the recess 31.

According to this embodiment, the LED in the concave portion 31
Since the lens 6 is formed on the upper part of the chip 1 with a sealing resin, it can be used for lighting applications having desired light distribution characteristics.

When the three-dimensional molded substrate 3 is molded, it is also possible to improve the heat radiation by simultaneously molding or attaching an inorganic material such as a metal material or a ceramic having a good thermal conductivity, or attaching it later. is there.

[0025]

As described above, according to the first aspect of the present invention, a plurality of LED chips and a plurality of first concave portions for accommodating each of the LED chips are formed and each of the first concave portions is formed. LE with the LED chip stored in the lower part of the recess
A three-dimensional molded substrate, on which a second concave portion having a reflecting wall for reflecting light emitted from the lower surface of the D chip in an upward direction is provided, and the upper surface extends from two opposing side walls of the first concave portion. A wiring pattern is formed over the LED chip, and the surface of the LED chip that is not the electrode surface is on the bottom surface side of the first concave portion;
The LED chip is mounted so that the electrode surface faces the wiring pattern formed on the side wall, and the electrodes of adjacent LED chips are connected by solder and the wiring pattern, so that the manufacturing process can be simplified. , Multiple LEDs
The semiconductor device on which the chip is mounted can be manufactured with high productivity, and the light emitted from the lower surface of the LED chip can be extracted to the outside, so that the luminous efficiency can be improved.

According to a second aspect of the present invention, in the first aspect of the present invention, solder plating is applied in advance to the wiring pattern formed on the side wall, and the solder plating is melted.
By connecting the electrodes of the adjacent LED chips by connecting the wiring patterns and the electrodes via the molten solder, the LED chips can be easily mounted in the first concave portions, and the solder plating is performed. When it is melted, the connection between the wiring pattern and the electrode is reliably performed.

According to a third aspect of the present invention, in the first aspect of the present invention, a solder foil is previously arranged on the wiring pattern formed on the side wall, and the solder foil is melted. By connecting the wiring pattern and the electrode by connecting the electrodes of the adjacent LED chips, it is easy to mount the LED chip in the concave portion, and when the solder foil is melted, the wiring pattern and the electrode are connected. Is reliably performed.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, if the side wall and the bottom surface of the recess form an obtuse angle, the light emitted from the side surface of the LED chip can be efficiently used. Can be taken out well.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, when the upper surface of the LED chip is sealed with a resin, a transparent resin is injected and cured by heating. If it is formed, it can be used for lighting applications having desired light distribution characteristics by setting the lens shape to a desired shape.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a plan state and a cross-sectional state of a part of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a state where the LED chip according to the above is mounted in a concave portion of an MID substrate.

FIG. 3 is a schematic diagram showing a cross-sectional state and a planar state of a part of a semiconductor device according to another embodiment of the present invention.

FIG. 4 is a schematic diagram showing a cross-sectional state and a planar state of a shape of a concave portion of the MID substrate according to the above.

FIG. 5 is a schematic diagram showing a cross-sectional state of a conventional LED element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LED chip 3 Three-dimensional molded board (MID board) 4 Wiring pattern 5 Solder 6 Lens 11 Electrode 12 Electrode 31 First concave part 32 Second concave part 33 Step 34 Side wall 35 Side wall 36 Reflection wall 37 Counterbore

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 33/00 H01S 5/00-5/50

Claims (5)

(57) [Claims] A plurality of LED chips and a plurality of first recesses for accommodating each of the LED chips are formed, and the LED chips are accommodated in a state where the LED chips are housed below the first recesses. A three-dimensionally formed substrate on which a second concave portion having a reflective wall for reflecting light emitted from the lower surface in an upward direction is provided, and a wiring pattern extending from two opposing side walls of the first concave portion to the upper surface. Is formed, and the L
The LED chip is mounted such that the non-electrode surface of the ED chip is on the bottom surface side of the first recess, and the electrode surface is opposed to the wiring pattern formed on the side wall.
A semiconductor device wherein electrodes of an ED chip are connected by solder and the wiring pattern. 2. A method in which solder plating is applied in advance on a wiring pattern formed on the side wall, the solder plating is melted, and the wiring pattern and the electrode are connected to each other via the melted solder, so that adjacent wiring patterns are formed. 2. The semiconductor device according to claim 1, wherein electrodes of the LED chip are connected. 3. A solder foil is previously arranged on a wiring pattern formed on the side wall, the solder foil is melted, and the wiring pattern and an electrode are connected to each other via the melted solder. 2. The semiconductor device according to claim 1, wherein the electrodes of the LED chip are connected. 4. The semiconductor device according to claim 1, wherein a side wall and a bottom surface of the recess form an obtuse angle. 5. A lens is formed by injecting a transparent resin and heating and curing the resin when sealing the upper surface side of the LED chip with a resin.
The semiconductor device according to claim 4.