JPH05129725A - Manufacture of semiconductor wafer and semiconductor laser - Google Patents

Abstract

PURPOSE:To reproduce a non-sagging cleavage orientation flat edge face, and to facilitate the alignment of the late patterning by a method wherein a groove, which is parallel with the direction of an orientation flat, is made at least in the surface. CONSTITUTION:A stitch-like groove 31, which is in parallel with a cleavage orientation flat 2, is formed in a substrate 12 before crystal growth. Then, after a crystal grown layer 4 has been formed on the substrate 12, a non-sagging cleavage edge face 21, which is in parallel with the orientation flat on the end face other than the groove 31, is formed by cleaving along the groove 31. The succeeding patternings are conducted referring to the cleavage edge face 21, and a resonator in the direction vertical to the cleavage edge face 21 is formed. Also, since a groove is made in the surface of the substrate, it is unnecessary that the substrate is treated by turning it over, and the surface of the substrate is not damaged. As a result, the sagging of the initial cleavage orientation flat is removed, and the orientation of the new cleavage end face can be brought to the same orientation as the cleavage orientation flat.

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 semiconductor wafer and a semiconductor laser.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing a state of a conventional semiconductor wafer having a circular shape (hereinafter also simply referred to as "wafer" or "substrate") when crystal growth is performed. Here, (a) of FIG. 3 is a top view (front surface) viewed from the direction in which the crystal growth of the wafer is performed (hereinafter also referred to as “front surface”), and (b) is a cleavage orientation flat of the wafer (hereinafter referred to as “orientation flat”). Is abbreviated as “.”).

In the figure, 11 is the back surface of the substrate, 12 is the front surface of the substrate (the surface of the substrate on which the crystal has been grown), 22 is the cleavage face of the orientation flat, and 4 is the crystal growth layer.

In a semiconductor laser, a cavity end face is generally formed by cleavage, so that it is required that the orientation of the cavity and the orientation of the crystal be accurately matched. Therefore, when a circular wafer is used, a method is performed in which an orientation flat is formed by cleaving in accordance with the crystal orientation, and the subsequent patterning process is performed with the orientation of the orientation flat as a reference.

[0005]

However, when crystals are grown on the wafer, the end face 22 of the orientation flat formed by cleavage becomes difficult to see due to sagging of the crystal growth layer 4,
There has been a problem that it becomes difficult to align the orientation in the subsequent patterning.

The present invention has been made in order to solve the above-mentioned problems. The first is a semiconductor wafer capable of reproducing a cleavage orientation flat face without sagging, and the second is a cleavage without sagging even after crystal growth. It is an object of the present invention to obtain a method for manufacturing a semiconductor laser in which an orientation flat end face is reproduced and alignment of subsequent patterning is easy.

[0007]

A semiconductor wafer according to the present invention has a stripe shape and a stitch shape parallel to the orientation of an orientation flat formed by cleavage on at least one surface (that is, the back surface, the front surface or both surfaces) of the wafer. And the like.

Further, in the method of manufacturing a semiconductor laser according to the present invention, a groove parallel to the orientation of the orientation flat is formed on at least one surface of the wafer, crystal growth is performed on the wafer surface, and then along the groove. This includes the step of cleaving.

[0009]

In the semiconductor wafer according to the present invention, the cleavage of the first cleavage orientation flat is removed by cleaving along the groove of the wafer after crystal growth, and the orientation of the new cleavage end face becomes the same orientation as the first cleavage orientation flat. Become.

Further, in the method of manufacturing a semiconductor laser according to the present invention, since the cleavage is performed along the groove parallel to the orientation flat of the wafer, there is no sagging of the crystal growth layer on the cleavage end face even after the crystal growth, and therefore, the cleavage end face. The crystal orientation of can be easily confirmed, and the subsequent patterning process can be facilitated.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 (a) and 1 (c) are bottom (back) views of a semiconductor wafer according to an embodiment of the present invention as viewed from the back side.
(d) is a cross-sectional view of an orientation perpendicular to the orientation of the orientation flat of the wafer. However, (a) and (b) show wafers after crystal growth and before cleavage, and (c) and (d) show wafers after cleavage.

In the figure, 2 is an end face of the cleavage orientation flat, 3 is a stripe-shaped groove formed on the back surface 11 of the substrate and parallel to the cleavage orientation flat 2, and 21 is a cleavage end face without sagging.
Incidentally, other numbers that are the same as those in the conventional example of FIG. 3 indicate the same or corresponding parts.

Next, a method of manufacturing a semiconductor laser using the wafer of this embodiment will be described. As shown in FIGS. 1 (a) and 1 (b), a groove 3 parallel to the orientation flat 2 formed by cleavage.
Are formed on the back surface side 11 of the circular wafer. Next, the crystal growth layer 4 is formed on the front surface side 12 of the wafer (see FIG. 1 (b)). After the crystal growth is completed, the wafer is cleaved along the groove 3 to form a cleaved end face 21 parallel to the cleaved orientation flat 2 and having no sag as shown in FIGS. 1 (c) and 1 (d).
Subsequent patterning is performed with reference to the orientation of the cleaved end face 21, and a resonator having an orientation perpendicular to the cleaved end face can be manufactured.

Further, another embodiment of the present invention will be described with reference to FIG. 2 (a) and 2 (c) are top (front) views seen from the surface direction of a wafer according to another embodiment, and FIG.
(d) is a sectional view of an orientation perpendicular to the orientation of the cleavage orientation flat of the wafer. However, (a) and (b) show wafers after crystal growth and before cleavage, and (c) and (d) show wafers after cleavage.

In the figure, 31 is a stitch-like groove formed on the substrate surface 12 and parallel to the cleavage orientation flat 2, and 21 is a cleavage end face (a portion other than the groove) cleaved along the groove 31. Incidentally, other numbers that are the same as those in the conventional example of FIG. 3 indicate the same or corresponding parts.

Next, a method of manufacturing a semiconductor laser using the wafer of this embodiment will be described. As shown in FIGS. 2A and 2B, a stitch-shaped groove 31 parallel to the cleavage orientation flat 2 is formed on the substrate surface 12 before crystal growth. Next, after the crystal growth layer 4 is formed on the substrate surface 12, the groove 31 is formed.
As shown in FIGS. 2 (c) and 2 (d), the end face other than the groove 31 is parallel to the orientation flat, and the cleaved end face 21 without sagging is formed by cleaving along. Subsequent patterning is performed with reference to this cleaved end face 21, and a resonator having an orientation perpendicular to the cleaved end face 21 can be manufactured. Further, in this embodiment, since the groove is formed on the surface of the substrate, there is no need to process the substrate inside out, and there is no fear that the surface of the substrate is damaged during the inside out.

In the above embodiments, the groove is formed only on either the front surface or the back surface of the substrate, but the groove may be formed on both surfaces of the substrate, and the shape of the groove is linear. It is not particularly limited to a groove (for example, stripe shape) or a partial groove (for example, stitch shape).

[0018]

As described above, according to the semiconductor wafer of the present invention, the sag of the first cleavage orientation flat is removed by cleaving along the groove of the wafer after crystal growth,
The orientation of the new cleavage end face is the same as the orientation of the first cleavage orientation flat. Therefore, it becomes easy to align the orientation in the subsequent patterning process.

Further, according to the method of manufacturing a semiconductor laser of the present invention, after the groove parallel to the cleavage orientation flat is formed on the back surface of the substrate, crystal growth is performed and the cleavage end face is formed along the groove. A non-cleavage end face can be formed on the wafer, and the crystal orientation of the cleavage end face can be easily confirmed. Therefore, the yield of the subsequent patterning process is improved, and it becomes easy to fabricate a resonator perpendicular to the cleaved end face.

Further, when the above-mentioned groove is formed on the surface of the substrate, there is no need to process the substrate inside out, and there is no risk of the substrate surface being damaged when the inside out.

[Brief description of drawings]

FIG. 1 is a diagram showing steps of a method for manufacturing a semiconductor laser according to an embodiment of the present invention, in which (a) and (b) are a bottom view and a sectional view of a wafer after crystal growth and before cleavage, respectively. c), (d)
3A is a bottom view and a cross-sectional view of a wafer after cleavage. FIG.

FIG. 2 is a diagram showing steps of a method for manufacturing a semiconductor laser according to another embodiment of the present invention, in which (a) and (b) are a top view and a cross-sectional view of a wafer after crystal growth and before cleavage, (c),
(d) is a top view and a sectional view of the wafer after cleavage.

3A and 3B are diagrams showing a state of a wafer when crystal growth is performed by a conventional method, where FIG. 3A is a top view of the wafer and FIG.
[FIG. 3] is a sectional view of a wafer.

[Explanation of symbols]

 2 Cleavage orientation flat 3 Groove formed on the back surface of the substrate 4 Crystal growth layer 11 Substrate back surface 12 Substrate surface 21 Cleaved end face without sagging 22 Cleaved orientation flat dull by crystal growth 31 Stitch-like groove formed on the substrate surface

Claims (3)

[Claims] 1. A semiconductor wafer, wherein a groove parallel to the orientation flat orientation is formed on at least one surface. 2. A step of forming a groove parallel to the orientation flat orientation on at least one surface of the wafer, a step of crystal growth on the surface of the wafer, and a step of cleaving the wafer along the groove. A method of manufacturing a semiconductor laser, comprising: 3. The method of manufacturing a semiconductor laser according to claim 2, wherein the groove is formed on the surface of the wafer.