JP2003124503A - Method for manufacturing light emitting diode chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently produce a light emitting diode chip excellent in light output efficiency. SOLUTION: A light emitting diode layer 2 where a plurality of light emitting diode regions are situated in a plane-form state is formed on a light transmissive main wafer 1, a dummy wafer 3 is applied on the main wafer 1 surface where a dummy wafer 3 is stuck on the main wafer 1 surface on the side where the light emitting diode layer 2 is formed to form a composite wafer 5. The composite wafer 5 is cut for each light emitting diode region to form a dice body 7. After the dice body 7 is polished in a spherical shape, the semiconductor wafer 1 part of the dice body 7 is separated away from the dummy wafer 3 part to form a light emitting diode chip.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a light emitting diode chip, and more particularly to a method for manufacturing a light emitting diode chip with high light extraction efficiency.

[0002]

2. Description of the Related Art As a light-emitting diode chip with improved light extraction efficiency, for example, in Japanese Patent Laid-Open No. 11-68153, a light-transmissive GaAs semiconductor substrate (wafer) 91 as shown in FIG. A dome-shaped light emitting surface that has been molded has been proposed. That is, a light emitting diode layer 92 including an active layer 921 is formed on the lower surface of the semiconductor wafer 91 by laminating thin films of GaAs, InGaP, InGaAs or the like, and electricity is supplied from the anode electrode 93 to the cathode electrode 94. Thus, the light L is output from the active layer 921 having the multiple quantum well structure. Since the active layer 921 is located substantially at the center of the hemispherical surface, the light L radially emitted from the active layer 921 is incident on the surface of the hemispherical semiconductor wafer 91 substantially vertically and the reflection there is greatly reduced. And is efficiently ejected to the outside.

[0003]

By the way, in the above-described conventional light emitting diode chip, the semiconductor wafer 91 has a hemispherical surface, but the light emitting diode layer 92 side is fixed to a predetermined jig, and the other side is fixed. The wafer surface is polished in the same way as lens polishing by using a hemispherical concave polishing plate. However, this method has a problem that the production efficiency is extremely poor because it is necessary to fix each of the small chips of about 0.6 mm square to a jig and individually apply a polishing plate to polish.

Therefore, the present invention is intended to solve such problems, and an object thereof is to provide a method of manufacturing a light emitting diode chip capable of efficiently producing a light emitting diode chip having a high light extraction efficiency.

[0005]

In order to achieve the above object, in the first aspect of the present invention, a light emitting diode layer (2) having a plurality of light emitting diode regions arranged in a plane is provided with a light transmitting semiconductor substrate (1). A dummy substrate (3) is formed on the semiconductor substrate (1) side on which the light emitting diode layer (2) is formed to form a composite substrate (5), and the composite substrate (5) is used for each light emission. The dice body (7) is cut into individual diode regions, and these dice bodies (7) are spherically polished, and then the semiconductor substrate (1) part of the dice body (7) is separated from the dummy substrate (3) part. To form a light emitting diode chip (CH).

In the first aspect of the present invention, since the dice body obtained by cutting the composite substrate may be polished into a spherical shape, a plurality of dice bodies are simultaneously and efficiently polished by using, for example, a ball polishing machine for manufacturing a bearing. can do. As a result, the manufacturing efficiency of the light emitting diode chip is significantly improved. The material of the dummy substrate does not necessarily have to be the same as that of the semiconductor substrate, but it is preferable that the dummy substrate has the same mechanical properties during polishing. Further, the dice body is not limited to the substantially cubic shape, and includes a polyhedral shape in which the cube is chamfered, or a rectangular parallelepiped shape.

In the second aspect of the present invention, a dicer (6) having an outer peripheral cutting edge (61) having a triangular cross section is used to cut the composite substrate (5) from the front and back to the bonding surface. .

In the second aspect of the present invention, since the dice body cut by the dicer becomes a polyhedron, the subsequent spherical polishing can be performed more efficiently.

The reference numerals in the parentheses indicate the correspondence with the specific means described in the embodiments described later.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) In FIG.
A light-transmissive semiconductor substrate (hereinafter referred to as a main wafer) 1 such as GaAs has GaAs, InGaP, I on one surface thereof.
A known light emitting diode layer 2 is formed by laminating thin films such as nGaAs. In the light emitting diode layer 2, a large number of light emitting diode regions are formed in a plane. The main wafer 1 has a surface on which the light emitting diode layer 2 is formed on the lower side, and a dummy substrate (wafer) 3 having the same material and substantially the same thickness as the main wafer 1 and having no light emitting diode layer is formed on the main wafer 1. It is joined from below with a hot melt wax 4 (FIG. 2).

As shown in FIG. 2, the composite wafer 5 obtained by bonding the dummy wafer 3 to the main wafer 1 is vertically and horizontally cut by a dicer 6 on the wafer surface for each light emitting diode region.
When the thickness of the main wafer 1 and the dummy wafer 3 is set to be approximately equal to the vertical and horizontal cut dimensions by the dicer 6, the separated composite wafer 5 becomes
The dice body 7 has a substantially cubic shape as shown in FIG.

Such a dice body 7 is supplied to a ball polishing machine 8 for manufacturing a bearing as shown in FIG. The ball polishing machine 8 rotates concentrically in opposite directions (arrow in FIG. 4).
It has an upper surface plate 81 and a lower surface plate 82, and these surface plates 81, 82
A ring-shaped recessed groove 83 (only one of which is shown) is formed at the same position on the opposing surface of the same so as to make one turn around the rotation center.
The concave groove 83 has an arc cross section (Fig. 5), and cemented carbide balls 84 (Fig. 4) are inserted at a plurality of positions in the circumferential direction, whereby the upper and lower surface plates 81, 82 are kept at a constant interval. Is dripping A circular cross-section space S is formed by the upper and lower concave grooves 83 that face each other with a gap, and a plurality of dice bodies 7 are arranged in the circular cross-section space S between the cemented spheres 84 to supply abrasive grains. The body 7 is polished. This polishing is usually performed in three steps of rough finishing, intermediate finishing and fine finishing. In this process, the material of the surface plates 81 and 82 is first made of soft neoprene rubber or the like and then changed to cast iron or the like. In addition, as the polishing of the dice body 7 progresses, the surface plates 81 and 82 having smaller grooves are successively replaced.

After the dice body 7 is polished into a spherical shape, as shown in FIG. 6, the heat-melting wax is melted to separate each dice body 7 into a main wafer portion 71 and a dummy wafer portion 72. As a result, a light emitting diode chip CH in which the active layer 73 is formed at the center of the lower surface of the light-transmitting main wafer 71 formed into a hemispherical surface is obtained. In this way, according to the present embodiment, a plurality of light emitting diode chips having a dome-shaped light emitting surface can be efficiently manufactured at the same time by using a ball polishing machine for manufacturing bearings.

(Second Embodiment) Outer peripheral cutting edge 6 of dicer 6
1 is formed into a triangular cross section as shown in FIG. 7 and the wafer surface of the composite wafer 5 is vertically and horizontally cut from the upper and lower sides to the respective bonding surfaces to cut each light emitting diode region. Since the decahedron shown in FIG. 8 is formed, the spherical polishing as in the first embodiment can be performed more efficiently.

[0015]

As described above, according to the method for manufacturing a light emitting diode chip of the present invention, a light emitting diode chip having a dome-shaped light emitting surface with good light extraction efficiency can be efficiently produced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view when a wafer is bonded in a first embodiment of the present invention.

FIG. 2 is a cross-sectional view at the time of cutting a wafer according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a dice body according to the first embodiment of the present invention.

FIG. 4 is a perspective view of a ball polishing machine according to the first embodiment of the present invention.

FIG. 5 is an enlarged sectional view of the ball polishing machine according to the first embodiment of the present invention.

FIG. 6 is a perspective view showing a separated die body after polishing in the first embodiment of the present invention.

FIG. 7 is a cross-sectional view of the second embodiment of the present invention during wafer cutting.

FIG. 8 is a perspective view of a dice body according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view of a conventional light emitting diode chip.

[Explanation of symbols]

1 ... Main wafer, 2 ... Light emitting diode layer, 3 ... Dummy wafer, 5 ... Composite wafer, 7 ... Dice body, 6 ... Dicer,
61 ... Outer peripheral cutting edge.

Claims (2)

[Claims] 1. A light emitting diode layer having a plurality of light emitting diode regions arranged in a plane is formed on a light transmissive semiconductor substrate, and a dummy substrate is attached to the semiconductor substrate surface on the side where the light emitting diode layer is formed. As a composite substrate, the composite substrate is cut into individual light emitting diode regions as dice bodies, and after these dice bodies are spherically polished, the semiconductor substrate portion of the dice bodies is separated from the dummy substrate portion to form a light emitting diode chip. A method of manufacturing a light-emitting diode chip, comprising: 2. The method for manufacturing a light-emitting diode chip according to claim 1, wherein the composite substrate is cut by cutting the composite substrate from the front and back surfaces to the bonding surface by using a dicer whose outer peripheral edge has a triangular cross section.