JPH033385A - Preparation of masked semiconductor laser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a mask semiconductor laser.

[Prior Art] A technology for recording and reproducing information by bringing a light source with a minute aperture close to an optical information recording medium is disclosed in Japanese Patent Laid-Open No. 62-18525.
It is disclosed in Publication No. 1, Publication No. 62-185268, etc. Furthermore, US Pat. No. 3,866,238 discloses a technique for recording and reproducing information on film.

A mask semiconductor laser is known as a light source used for recording and reproducing such information (see USP 38662 above).
38 specification), a masked semiconductor laser has a light-shielding mask formed on the emission end face of the semiconductor laser, that is, a mask that shields light emitted from the semiconductor laser, and a light-emitting portion provided on this mask. This is a light source that can extract light emitted from a semiconductor laser.

By limiting the light emitting area of the light emitted by the semiconductor laser using the mask having the light emitting portion, it becomes possible to form a sharp spot on the optical information recording medium, for example.

As a method of forming a light emitting part on a mask provided on the emission end face of a semiconductor laser, a method is known in which the semiconductor laser itself provided with the mask oscillates and a part of the mask is removed using the power of the semiconductor laser (see above). usP386623
Specification No. 8).

[Problems to be solved by the invention] Although the method of forming a light emitting part using the oscillation power of a semiconductor laser is simple, it is difficult to control the aperture size of the light emitting part, and it is difficult to control the aperture size of the light emitting part. It is difficult to realize a light emitting part with a

In addition, the material of the mask is limited to those that can be removed by the oscillation power of the semiconductor laser, so there are strict restrictions on the material.Also, the aperture size of the light emitting part formed by the skin gradually expands while being used as a light source. There is a problem.

The present invention was made in view of the above-mentioned circumstances, and
The aim is to effectively solve the above-mentioned problems. The object of the present invention is to provide a new method for manufacturing a mask semiconductor laser.

[Means to solve the problem] The present invention will be explained below.

The present invention is a method for manufacturing a mask semiconductor laser, and its features include the following points.

That is, as a first step, a light-shielding mask layer is formed on the emission end face of the semiconductor laser. The light-shielding property means the light-shielding property against the emitted light of the semiconductor laser itself.

The mask layer may be structurally a single layer, or may have a composite layer structure in which a plurality of layers are laminated.

As a second step, a part of the mask layer is removed or made transparent by irradiating the mask layer with synchrotron radiation or radiation from the outside, thereby forming a light emitting part for emitting light from the semiconductor laser. do.

Synchrotron radiation refers to visible light, laser light, and other light, and radiation refers to electron beams and ion beams.

Furthermore, "removing a part of the mask layer by irradiating the mask layer with synchrotron radiation or radiation from the outside" refers to the case where a part of the mask layer is directly removed by the action of synchrotron radiation or synchrotron radiation. It also includes a case where a part of the mask layer is altered by the action of synchrotron radiation or radiation, and the portion of the mask layer that includes this altered part is removed by a physical or chemical method.

In addition, "transparency" can be used to directly make a part of the remask layer transparent by the action of synchrotron radiation or radiation, or to change the quality of a part of the mask layer by the action of synchrotron radiation or radiation, and to make the altered part transparent. This also includes cases where it is made transparent by chemical methods.

[Function 1] As described above, in the method of the present invention, a light emitting portion is formed in the mask layer formed on the emission end face of the semiconductor laser by the action of synchrotron radiation or radiation irradiated from the outside.

[Embodiments] Hereinafter, specific embodiments will be described with reference to the drawings.

Example 1 In FIG. 1, reference numeral 1 indicates a Fapley-Perot type semiconductor laser.
Double hetero lasers such as aAs, GaAlAs, InP, AIGaInP and others can be used.

FIG. 1(A) shows a state in which a transparent dielectric film 2 and a light shielding film 3 are laminated on the emission end face of a semiconductor laser 1. The transparent dielectric film 2 is made of, for example, SiO, SiO, Si, or N.

JgF, etc. may be formed by vacuum evaporation, sputtering, CVD, etc. The light shielding film 3 is made of a material that is strong against the emission power of the semiconductor laser. The film can be formed by suitably using a material that does not cause the above, for example, metals such as Ti, AI, Ni, and AU, Ti-1 alloy, and Ni alloy.

The first @ (B) shows a state in which a photoresist layer 4 is further provided on the light shielding film 3. The steps up to this point are the first step described above, and the photoresist layer 4 is laminated on the emission end face of the semiconductor laser 1. In addition, the transparent dielectric film 2, the light shielding film 3, and the photoresist layer 4 constitute a mask layer.

Next, as shown in FIG. 1(C), a pattern mask 5 is brought into close contact with the photoresist layer 4. The pattern mask 5 has an opening pattern 5A shaped like the opening of the light emitting section, and the opening pattern 5A is aligned with the position of the light emitting section of the semiconductor laser 1 using alignment marks (not shown).

The shape of the opening pattern 5A is set to a desired shape, such as a circular shape or a rectangular shape, which is determined as the shape of the opening of the light emitting portion.

In this state, light (blue to blue) is transmitted through the pattern mask 5.
When irradiated with ultraviolet light, the photoresist layer 5 is exposed in the shape of an open pattern 5A.

After exposure, when development is performed, the exposed photoresist layer portion is removed and the micropores 4A are formed, as shown in FIG.
is formed.

In this state, when the light-shielding film 3 is subjected to wet etching or dry etching using gas, the light-shielding film 3 is etched according to the four micropores of the photoresist 4, and the light-emitting portion 3A is formed. (Figure 1 (E)).

Finally, the photoresist 4 is removed using an organic solvent such as amethane to obtain a mask semiconductor laser as shown in FIG. 1(F). The shape of the light emitting part 3A of this mask semiconductor laser follows the shape of the open pattern 5A in the pattern mask 5.

As is clear from the above explanation, "a part of the mask layer is removed by irradiating the mask layer with synchrotron radiation from the outside,
The process of "forming a light emitting section for emitting light from a semiconductor laser" is executed by the plurality of steps described with reference to FIGS. 1(C) to 1(F).

The method of exposing the photoresist layer 4 is not limited to the method of using the above-mentioned pattern mask in close contact with the photoresist layer 4, but also the projection exposure method in which an image of the pattern mask is formed on the photoresist layer through a projection lens. It's also good.

Further, as a light source for exposure, visible light, ultraviolet light, or X-rays can also be used.

Example 2 As shown in FIG. 2, on top of the semiconductor laser 1.

A mask layer is formed by the transparent dielectric 1112, the light shielding film 3, and the photoresist layer 4, and without using a pattern mask,
Using the condensing lens 7, Ar ion laser or He-Cd
A short-wavelength laser beam, such as a laser beam, is focused directly onto the photoresist layer 4 to expose a minute spot. The diameter of the minute spot can be adjusted by adjusting the NA of the condenser lens 7.
Spots with a diameter of ~0.5 μm can be easily exposed.

The steps after exposure are the same as in Example 1 described above.

Embodiment 3 As shown in FIG. 3, a mask layer is formed on a semiconductor laser 1 by a transparent dielectric film 2, a light shielding film 3, and an electron beam resist layer 4'. The open pattern is irradiated with the electron beam 8 . The portion of the electron beam resist 4' irradiated with the electron beam is removed by development.

After etching, the desired mask semiconductor laser can be obtained by removing the electron beam resist 4'.

By using an electron beam, the shape of the light emitting part can be formed more precisely, and by scanning the electron beam, the degree of freedom in the shape of the light emitting part can be significantly increased.

A focused ion beam may be used instead of an electron beam.

Embodiment 4 As shown in FIG. 4, a mask layer is formed on the semiconductor laser 1 by laminating five transparent dielectric films 2 and a light shielding film 3. In this state, a YAG laser or Ar
A high-power laser beam, such as a laser beam, is directly focused onto the mask layer by a condensing lens 7, and the light shielding film 3 is evaporated at the light irradiation section to form a light emitting section. In this case, the material of the light-shielding film 3 may be appropriately selected, and the light-shielding film may be made transparent by the laser beam irradiation portion to serve as the light-emitting portion.

In this example, the process of "removing or making transparent a part of the mask layer by irradiating the mask layer with synchrotron radiation from the outside and forming a light emitting part for emitting light from the semiconductor laser" is It can be realized most simply and directly.

Example 5 Example 5 is a modification of Example 1.

The feature is that the mask layer and the light emitting part are formed at the block stage before the semiconductor lasers are individually chipped.

In FIG. 5, reference numeral 10 indicates a block before being chipped into individual semiconductor lasers, and a transparent dielectric film 20 and a light shielding film 30 are formed on a common radiation end face of this block.
and a photoresist layer 40 are laminated in common to form a mask layer, and a plurality of open patterns 5A-1, 5A-2, 5A-3 are formed.
, , , is aligned and brought into close contact with the photoresist layer 40, and the entire area is exposed to light to form an open pattern.2 After that, development, etching, and removal of the photoresist layer are performed. A process is performed to form a light emitting part, and then cleavage is performed at the position of broken line 9 to complete a mask semiconductor laser chip.

In Examples 1 to 5 above, transparent dielectric @3.30 was used as part of the mask layer. This transparent dielectric film is for electrically insulating the light shielding film and the semiconductor laser. Therefore, if the light-shielding film itself is formed of an insulating or highly resistive material, the transparent dielectric film is not necessarily necessary, and the mask layer can be used as an electrically insulating light-shielding film alone (in the case of Example 4) or as an electrically insulating film. light-shielding film and photoresist layer (
(in the case of Examples 1, 2.5), or an electrically insulating light-shielding film and an electron beam resist layer (in the case of Example 3).

[Effects of the Invention] As described above, according to the present invention, a novel method for manufacturing a mask semiconductor laser can be provided.

Since this method is configured as described above, the shape and size of the light emitting portion can be controlled with high precision. Also,
Since restrictions on the material of the mask layer are loose, an appropriate material can be selected from a wide range of materials, and the enlargement of the light emitting portion over time can be effectively prevented.

[Brief explanation of drawings]

Figure 1 is a diagram for explaining one embodiment of the present invention, Figure 2 is a diagram for explaining one embodiment of the present invention.
The figures are diagrams for explaining another embodiment, FIG. 3 is a diagram for explaining another embodiment, FIG. 4 is a diagram for explaining still another embodiment, and FIG. 5 is a diagram for explaining another embodiment. FIG. 2 is a diagram for explaining a modification of the embodiment shown in FIG. 1. FIG. 109. Semiconductor laser, 200. transparent dielectric film, 3.
,.

Claims (1)

[Claims] A light-shielding mask layer is formed on the emission end face of the semiconductor laser, and by irradiating this mask layer with synchrotron radiation or radiation from the outside, a part of the mask layer is removed or made transparent, and the light from the semiconductor laser is blocked. A method for manufacturing a mask semiconductor laser, the method comprising forming a light emitting part for emitting light.