JPH11354836A - Full color semiconductor light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a full color light emitting device in which reliability can be enhanced by enhancing resistance against high voltage of static electricity or surge while simplifying electric connection. SOLUTION: The full color semiconductor light emitting device combines an Si diode 1 for protection against static electricity and semiconductor light emitting elements 4, 5, 6 of red, green and blue mounted on the Si diode 1 while conducting therewith. A circuit pattern for conducting the semiconductor light emitting elements 4-6 with an external electric circuit is formed in the Si diode 1 to obtain an assembly where the semiconductor light emitting elements 4-6 can be mounted on the Si diode 1. Furthermore, overall height is reduced by making a recess for containing the semiconductor light emitting elements 4-6 in the Si diode 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-emitting device including semiconductor light-emitting elements of R, G, and B colors, and more particularly, to combining a circuit pattern with an electrostatic protection element for improving the electrostatic breakdown voltage of the light-emitting element. The present invention relates to a full-color light-emitting semiconductor light-emitting device whose assembly is simple and thin.

[0002]

2. Description of the Related Art Light-emitting devices using semiconductor light-emitting elements, such as LED lamps and chip-type LEDs, are widely used in, for example, LED displays in which a large number of these LED lamps and chip-type LEDs are arranged on a panel. A semiconductor light emitting element is generally a pn junction in which a compound semiconductor is stacked on the same compound semiconductor substrate to form a p-type layer and an n-type layer. Depending on the type of the compound semiconductor, a red (R ) Or green (G). In recent years, blue (B) and green (G) in which a GaN-based compound semiconductor is mainly laminated on an insulating and transparent sapphire substrate are used.
Have been developed and are now offered as products with high light emission luminance.

In the case of an LED display, one pixel is constituted by one LED in the case of a single color display. For example, in the case of three colors of red, orange and green, one red LED and one green LED are used. One pixel, orange is red L
This is displayed by causing the ED and the green LED to emit light at the same time to mix colors. On the other hand, recently, for full-color display, a light-emitting display device using a combination of R, G, and B, which are three primary colors of light, as one pixel has become mainstream. In general manufacture of such a full-color light-emitting device having R, G, and B as one pixel, a light-emitting element of each color in which a compound semiconductor is grown and laminated on a substrate is separately die-bonded, and these light-emitting elements are formed. In general, a process of performing wire bonding to electrically connect each of them independently is generally performed.

[0004] Of the light emitting elements of the three primary colors R, G, and B, GaN-based compound semiconductors are used for G and B in order to obtain high emission luminance. However, GaN-based compound semiconductors have a property of lowering the electrostatic withstand voltage as compared with other types of compound semiconductors for forming light-emitting elements. For this reason,
Compared to the R light emitting element, the G and B light emitting elements have a lower electrostatic withstand voltage, and thus are more likely to be destroyed by electrostatic discharge when a high voltage such as static electricity or surge is applied. In particular, a GaN-based compound semiconductor is essential. Regarding the light emitting element B, the effect of this electrostatic breakdown cannot be ignored.

As described above, since the G and B light emitting elements tend to be easily destroyed by electrostatic discharge, the combination of the R and G light emitting elements or the combination of the R and B light emitting elements is regarded as one pixel,
It also affects multicolor light emission in which the combination of the G and B light emitting elements is a pixel unit. That is, while the R light emitting element is free from electrostatic destruction, the G and B combined therewith are electrostatically destroyed by an overcurrent such as static electricity. And the full-color light emitting function of the three primary colors of light is lost.

As described in Japanese Patent Application Laid-Open No. 9-148625, the electrostatic breakdown voltage of a light-emitting element using a GaN-based compound semiconductor is reduced against the electrostatic breakdown of the G and B light-emitting elements. Providing a compensating diode for reverse breakdown voltage compensation for improvement can be one effective means. It is also known that electrostatic breakdown can be prevented by, for example, electrically connecting a light-emitting element to a Zener diode using an n-type silicon substrate so that the p-side and the n-side have opposite polarities.

FIG. 4 is a schematic diagram showing a configuration example applicable to a full-color R, G, B light emitting device using a Zener diode as an electrostatic protection element. FIG. 4A is a side view, and FIG. (B) is a plan view.

In the figure, wiring patterns 51a, 51
Each of the wiring patterns 51a, 51b, and 5c is mainly composed of a printed circuit board 51 in which b and 51c are formed in advance at a wafer stage.
1c, three R, G, B in the illustrated example.
Of light emitting elements 52, 53, 54 are arranged. And
In order to maintain the electrostatic withstand voltage of these light emitting elements 52 to 54,
The zener diodes are mounted on zener diodes 55, 56 and 57 which are electrically connected to the respective wiring patterns 51a to 51c.

The Zener diodes 55 to 57 use, for example, an n-type silicon substrate, and have an n-electrode formed on the bottom surface thereof and are mounted to be conductive to the wiring patterns 51a to 51c. A p-type semiconductor region is partially diffused and formed on the upper surface, and an n-side electrode and a p-side electrode are joined to the n-type silicon substrate and the p-type semiconductor region, respectively. 51a-
Bonded to 51c. On the other hand, the light emitting elements 52 to 5
Reference numeral 4 denotes a flip-chip type, in which the n-side and p-side electrodes are made to be conductive to the zener diodes 55 to 57 with opposite polarities.

As described above, the zener diodes 55 to 5 are connected to the light-emitting elements 52 to 54 by setting the p-side and n-side electrodes to opposite polarities.
By mounting the light-emitting elements 7 on the light-emitting elements 7, the light-emitting elements 52 to 54 can be prevented from being destroyed even when an overcurrent such as static electricity flows.

[0011]

However, the light emitting element 5
Since the elements 2 to 54 are mounted on the Zener diodes 55 to 57 to form a composite element, compared to the case where the light emitting elements 52 to 54 are simply mounted on the printed circuit board 51, only the amount of the embedded Zener diodes 55 to 57 is required. The height dimension increases. For this reason, in the unit of the light emitting device for full-color light emission of R, G, and B by the printed board 51 and all the light emitting elements 52 to 54, the electrostatic protection of the light emitting elements 53 and 54 of G and B, which have particularly low electrostatic withstand voltage. However, the degree of freedom in thinning is reduced, which hinders miniaturization of the product.

In the assembly, the steps of mounting the Zener diodes 55 to 57 on the printed circuit board 51 and bonding by wires are performed.
A step of mounting each of the light emitting elements 52 to 54 on 5 to 57 is required. In this case, for example, the Zener diode 55
To 57 are formed in a wafer state, and the light emitting elements 52 to 54 mounted thereon are diced and prepared in advance as a composite element. As a result, apparent man-hours are reduced.

However, the combination of the three members, that is, the printed board 51, the light emitting elements 52 to 54, and the zener diodes 55 to 57 remains unchanged, and there is a limit to the reduction in the number of steps for assembly. Further, since the number of assembling steps is large and the mounting accuracy of the light emitting elements 52 to 54 with respect to each of the zener diodes 55 to 57 has to be strictly controlled, the production yield is greatly affected.

As described above, R,
In a light-emitting display device having a combination of G and B as one pixel, when compensating for the electrostatic withstand voltage by using a Zener diode, there remains a problem to be solved in terms of thinning a product and manufacturing yield.

The problem to be solved in the present invention is to provide a light emitting device capable of full-color light emission, which is simple in electrical connection and can improve reliability by improving withstand voltage against application of a high voltage such as static electricity or surge. It is in.

[0016]

SUMMARY OF THE INVENTION The present invention provides a full-color semiconductor comprising a combination of a Si diode for electrostatic protection and semiconductor light emitting devices of red, green and blue colors which are conductively mounted on the Si diode. A light emitting device, wherein the Si diode is formed with a circuit pattern for electrically connecting the semiconductor light emitting element to an external electric circuit.

In this configuration, since the Si diode for electrostatic protection can be a member that also serves as a conventional circuit board, an assembly in which the light emitting element is mounted on the Si diode is sufficient, and the height dimension is reduced. be able to.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention of claim 1 is a full-color combination of a Si diode for static electricity protection and semiconductor light-emitting elements of red, green and blue which are conductively mounted on the Si diode. A semiconductor light emitting device, wherein the Si diode is formed with a circuit pattern for electrically connecting the semiconductor light emitting element to an external electric circuit, and only an assembly for mounting the light emitting element on the Si diode is sufficient. A product with a short height can be obtained.

According to a second aspect of the present invention, in the full-color semiconductor light emitting device according to the first aspect, the Si diode has a recess for mounting the semiconductor light emitting element of each color. By putting in
This has the effect of reducing the stacking height of the i-diode and the semiconductor light emitting element.

Hereinafter, specific examples of the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic plan view showing a main part of a full-color semiconductor light emitting device according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of the main part taken along a plane including a light emitting element.

The light emitting device of the present invention includes one Si diode 1 as a member that also serves as a printed board, and three sets of R, G, and B light emitting elements described later are arranged on the Si diode 1 in pixel units. Things.

The Si diode 1 uses, for example, an n-type silicon substrate, and as shown in FIG.
The recesses 1a, 1b,
1b-1. And these recesses 1a to
Corresponding to 1b-1, wiring patterns 2a, 2b, and 2c and patterns of electrodes 3a, 3b, and 3c that are electrically connected to these are provided.

The R, G, and B light emitting elements 4, 5, and 6 mounted in the recesses 1a to 1b-1, respectively, are of a flip chip type, and FIG. Show.

The Si diode 1, as shown in FIG.
The wiring pattern 2a to 2c and the electrodes 3a to 3c described with reference to FIG. 2 are formed on the surface side using an n-type silicon substrate 1c as a base material. Then, an oxide film 1d is formed to cover except for a part of the bottom surface of the concave portion 1b-1, and the oxide film 1d is formed.
The p-type semiconductor region 1e is diffused and formed by implanting p-type impurity ions using a portion not covered by the above as a diffusion window.

On the surface of the n-type silicon substrate 1c, an n-electrode 1f and a p-electrode 1g are respectively formed by a metal deposition method. The n-electrode 1f is formed so as to be biased toward the right end of the concave portion 1b-1 and extends up to the inclined surface, and is electrically connected to the n-type silicon substrate 1c by a portion where the oxide film 1d is not formed. This n-electrode 1f can use aluminum, for example.
The inclined surface portion is used as a light reflection layer by the n-electrode 1f. On the other hand, the p-electrode 1g is joined to the p-type semiconductor region 1e formed by diffusion in the n-type silicon substrate 1c.

The light emitting element 6 of B has a GaN-based compound semiconductor laminated on an insulating sapphire substrate, and an InGaN active layer formed as one of the layers is used as a light emitting layer. It is mounted on the upper surface.

That is, as shown in FIG.
Is formed by forming an n-side electrode 6b and a p-side electrode 6c on the respective surfaces of an n-type layer and a p-type layer laminated on a transparent sapphire substrate 6a by a vapor deposition method. In addition, these n
Micro bumps 6d and 6e are formed on the surfaces of the side electrode 6b and the p-side electrode 6c, respectively. Then, the light emitting element 6 is mounted so as to straddle the n-electrode 1f and the p-electrode 1g of the Si diode 1, and the n-side electrode 6b and the p-side electrode 6
c is mounted on the p electrode 1g and the n electrode 1f, respectively.

P-electrode 1g formed on Si diode 1
Are electrically connected to the n-side electrode 6b of the light emitting element 6 and the wiring pattern 2c. The n-electrode 1f and the p-electrode 1g are formed by vapor deposition of a metal having high light reflectivity such as aluminum, and use the inclined surface of the inner peripheral wall portion of the concave portion 1b-1 as a reflecting surface in the light emitting direction.

The mounting structure described above is exactly the same when the R and G light emitting elements 4 and 5 are incorporated into the concave portions 1a and 1b.

In the above configuration, when the R, G, and B light emitting elements 4, 5, and 6 are energized, light is emitted from each of the light emitting layers. Although there is a component of light that goes down and to the side, light is emitted with the surface facing upward in FIG. 3 being the main light extraction surface because the sapphire substrate is transparent. Therefore, full-color light emission can be obtained by the respective light-emitting colors of the light-emitting elements 4, 5, and 6 of the three primary colors of R, G, and B light and a combination thereof.

Further, the provision of the Si diode 1 can prevent the electrostatic breakdown of each of the light emitting elements 4, 5, and 6, and in particular, requires a GaN-based semiconductor compound having a low electrostatic withstand voltage.
Since the durability of the light-emitting element 6 is also improved, a light-emitting display that effectively utilizes the full-color-compatible pixels of the combination of the R, G, and B light-emitting elements 4, 5, and 6 can be performed.

As described above, the R, G, and B light emitting elements 4,
By incorporating the light emitting elements 4, 5 into the recesses 1a, 1b, 1b-1 respectively,
There is no optical interference between 5 and 6.
For this reason, light absorption due to the difference in band gap energy of the material used for each of the light emitting elements 4, 5, and 6 is suppressed, so that each emission color is further sharpened and a high emission output is obtained. Further, since light is reflected in the direction of the main light extraction surface by reflection of light using an electrode provided on the inclined surface of each of the recesses 1a to 1b-1, light emission luminance can be further improved.

Here, in the present invention, the wiring patterns 2a to 2c and the electrodes 3a to 3c
Is formed, and each of the light emitting elements 4 to 6 is conductively mounted. That is, since the Si diode 1 can be used also as a circuit board, the wiring pattern 2a
2c and the electrodes 3a to 3c are prepared in advance, and only the process of chip bonding for mounting the light emitting elements 4 to 6 is required.

Each of the light emitting elements 4 to 6 has a concave portion 1a.
-1b-1 and incorporated so as not to protrude from the surface of the Si diode 1, so that the overall height dimension can be reduced and the light emitting device finally manufactured can be made thinner. .

[0035]

According to the first aspect of the present invention, the S for static electricity protection is provided.
Since the i-diode can be a member that also serves as a conventional circuit board, an assembly that simply mounts the light-emitting element on the Si diode is sufficient, and the static electricity protection element is mounted on the conventional board, and the light-emitting element is further mounted thereon. The manufacturing yield is improved as compared with the structure in which the is mounted. Further, since the Si diode and the light emitting element are stacked, the height dimension is reduced, and the light emitting device can be made thin.

According to the second aspect of the present invention, since the light emitting element is housed in the recess of the Si diode, the stack height of the Si diode and the semiconductor light emitting element can be further reduced.
If the configuration is such that the entire light emitting element falls into the concave portion, S
A product having a thickness of only the i-diode is obtained.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a full-color semiconductor light emitting device according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of an essential part taken along a plane including a light emitting element in FIG.

FIG. 3 is a schematic view showing a main part of a mounting structure of a light emitting element for emitting blue light.

FIG. 4 (a) is a schematic side view showing a conventional example in which a Zener diode and a light emitting element are combined, and FIG. 4 (b) is a plan view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Si diode 1a, 1b, 1b-1 Concave part 1c n-type silicon substrate 1d oxide film 1ep p-type semiconductor region 1f n-electrode 1g p-electrode 2a, 2b, 2c Wiring pattern 3a, 3b, 3c electrode 4 Light-emitting element 5 Light-emitting element 6 Light emitting element 6a Sapphire substrate 6b n-side electrode 6c p-side electrode 6d, 6e Micro bump

Claims (2)

[Claims] 1. A full-color semiconductor light-emitting device comprising a combination of an Si diode for electrostatic protection and semiconductor light-emitting elements of red, green, and blue conductively mounted on the Si diode, A full-color semiconductor light-emitting device in which a diode is formed with a circuit pattern for electrically connecting the semiconductor light-emitting element to an external electric circuit. 2. The full-color semiconductor light emitting device according to claim 1, wherein the Si diode has a concave portion in which the semiconductor light emitting element of each color is dropped and mounted.