JPS61187383A - Manufacture of semiconductor light emitting element - Google Patents

Abstract

PURPOSE:To remove the overhangs of a metal layer by forming a circular pattern and a doughnut-shaped pattern concentric with the pattern on a metal layer, etching the metal layer to expose the circular pattern, and selectively etching it. CONSTITUTION:After layers 2-5 are epitaxially grown on a substrate 1, an insulating film 7 is accumulated, a current implanting hole is formed. A P-type side electrode layer 8 and an N-type side electrode layer 10 are provided. Then, a doughnut-shaped ring having 180mum of inner diameter and 220mum of outer diameter is formed concentrically with the hole of approx. 100mum of diameter on the second main surface 11 by photolithography and chemical etching to expose the substrate 1. A hole of 100mum of diameter is matched to the center by photolithography on the above surface, and the substrate 1 of the portion is removed by etching. Then, a resist 12 is removed to eliminate the overhangs of a metal layer. Thus, a light producing surface 9 is completely enclosed by the resin molding to hardly store air bubbles.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improvement in a method of manufacturing a semiconductor light emitting device, and particularly relates to the formation of a light extraction surface.

[Conventional technology]

Semiconductor light emitting devices have high electrical and optical conversion efficiency, and the light emission intensity can be modulated extremely easily by modifying the t1 injection current, so in recent years they have been put into practical use as light sources for optical fiber communications. . A double heterojunction structure has been developed in such a semiconductor light emitting device for optical fiber communication, which is composed of a compound semiconductor such as GaAs/GaAlAs or uInk/InGaAsP, in order to increase luminous efficiency.

As a surface-emitting light emitting diode, A I Ga As
In a double heterojunction crystal edible semiconductor type light emitting diode, the GaAs substrate near the light emitting region is removed to prevent the light emitted inside the active layer from being absorbed by the GaAs substrate with a small band gap in the active layer. The big transparent A jt' x G a knee x
It is taken out to the outside through the A s cladding layer (wind layer).

Conventionally, a metal layer deposited on the second main surface 11 is removed by photolithography and chemical etching to form a metal layer on the light extraction surface, and then a semiconductor substrate is hole-etched.

[Problem that the invention seeks to solve]

In the conventional example shown in Fig. 3, the depth of the hole etching is 40 to 60 μrn. When etching the semiconductor substrate 1, the semiconductor substrate 1 is also etched laterally depending on the depth, and the diameter of the hole 90 on the light extraction surface is 40 to 60 μrn. 100 μm before and after starting etching
The φ machining is also about twice as large, and as a result, the metal layer is formed in the shape of an eaves, and when molding resin into a dome shape on the light extraction surface 9, the resin hangs down on the eaves of the metal layer. , the defect that it was difficult for the light to enter completely was observed in most of the light extraction surface. In addition, air bubbles are likely to occur, and these air bubbles cause a decrease in the light emitting output.Furthermore, during bonding, a load is applied to the eaves, causing damage to the 7t4 pellet. An object of the present invention is to provide a method for manufacturing a semiconductor light emitting device that eliminates the above-mentioned drawbacks.

According to the present invention, in the step of providing a light 1VL exit surface on the second main surface of the semiconductor wafer 14 having a double heterojunction structure, a circular pattern is formed on the metal layer deposited on the N2 main surface. A concentric dot-shaped pattern is formed, and the metal layer exposed in the circular and donut-shaped pattern portions is etched, and then photolithography is performed to expose only the first circular pattern. A method for manufacturing a semiconductor light emitting device is obtained, which is characterized in that by selectively etching that portion, an original extraction surface can be formed without forming an overhang of the F metal layer.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. N1 is a cross-sectional view of a semiconductor light emitting device obtained from an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of the main steps of the embodiment. The semiconductor light emitting device to be manufactured is epitaxially grown on a semiconductor substrate 1 made of n-GaAs.
Loρa (wind layer 2 consisting of L 7 A s, P
-Al o, o a Active layer 3 consisting of G"0.97AS, P-AJ 13 Ga (h yAs Kara 6
le confinement/14°P-AJ, □5Gao, 85As
An insulating film 7 consisting of an electrode forming layer 5t consisting of a conventionally known double heterojunction structure and a current confinement method using a current conductive entry opening 61C. Or-
P suppressing electrode layer 8 consisting of kl-Ti-P, t-Au. Light extraction surface 9. It is composed of an n-side electrode 10 made of an Au-Ge-Ni alloy.

This embodiment is a semiconductor light emitting device called a light emitting diode, and a PII1111L pole layer 9 has positive and n side electrodes 10.
A full negative voltage is applied to the active layer 30 from the current entry opening 6.
When a current is injected into the light emitting region 3a, light with a wavelength of about 0.85 μm is obtained, and the light is extracted to the outside through the light extraction surface 10.

The main ABE shape release of this example is shown in Figure 2 (N7). After epitaxially growing the layers 2 to 5 above on the semiconductor substrate 1, the area is insulated by CVD as shown in Figure 2+bl. After the film 7t is deposited to a thickness of approximately 0.3 μm and a current injection portion opening 6t is formed by photolithography and chemical etching, an edge P side electrode layer 8 and an n side electrode 1o are formed by vacuum evaporation. The n-side of the substrate 1 is polished to a thickness of approximately 40 to 60 μm prior to the formation of the pole 10.

In Figure 2 (C), a hole with a diameter of approximately 100 μmφ and a hole with an inner diameter of 180 μm are formed concentrically on the main surface 110 of 21E2 at the portion corresponding to the light extraction surface.
The semiconductor substrate 1 is exposed by forming a donut-shaped ring having an outer diameter of 220 μm. What is shown in FIG. 2(d) is that a hole with a diameter of 100 μmφ is aligned in the center using photolithography on the surface formed in FIG. (1:30
) It has been removed by etching with a solution. 6g
Figure 2 (i6) shows the state after removing the resist used in photolithography.

〔Effect of the invention〕

In the embodiment, the metal layer is removed on the second main surface 12 corresponding to the outer diameter of the hole in which the etched area shown in FIG. Since the overhang of the metal layer is eliminated, the semiconductor light emitting device obtained from this example has fc, which is a drawback of the conventional example. In the resin mold, the light extraction surface 9 can be wrapped in a metal pre-metallic material, and air bubbles are less likely to accumulate, thereby preventing a decrease in light emitting output. Furthermore, there is no longer any accident of damaging the pellet due to applying load to the original part during bonding.

Finally, to summarize the inventive features, since there is no overhang of the metal layer, it is possible to obtain a semiconductor light emitting device that enhances the resin molding effect, prevents a decrease in light output, and eliminates mistakes in bonding work.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a semiconductor light emitting device obtained from an embodiment of the present invention, Fig. 2 (a) to (elrL- cross-sectional schematic diagram of the main steps involved in the implementation sequence), and Fig. 3 is a semiconductor light emitting device of a conventional example. It is a sectional view of an element. In the figure, 1... semiconductor substrate, 2... window layer, 3... active layer, 3a... light emitting region, 4...Confinement layer, 5...Electrode forming layer, 6...Current entry opening, 7...
Insulating film, 8... P side 'aL other layer, 9...
・Light extraction surface, 10... n-side electrode, 11...
...Main surface of f42, 12...Resist,
13...Metal layer eaves, 14...Semiconductor wafer ~-1.

Claims (1)

[Claims] In the step of providing a light extraction surface on the second main surface of a semiconductor wafer having a double heterojunction structure, a metal layer formed on the second main surface includes a circular pattern and a donut-shaped pattern concentric with the circular pattern. The metal layer exposed in the patterned portion is etched, and the circular pattern is exposed by photolithography and selectively etched to form the light extraction surface without forming an eaves of the metal layer. 1. A method for manufacturing a semiconductor light emitting device, comprising: forming a semiconductor light emitting device.