JP7096476B2 - Manufacturing method of semiconductor laser device - Google Patents

Description

The present invention relates to a semiconductor laser device and a method for manufacturing the same.

As a background technique in this technical field, Japanese Patent Application Laid-Open No. 55-38064 (Patent Document 1) is available. In this publication, "a semiconductor laser is fixed to a heat sink on an insulating substrate, the distance from the end face of the semiconductor laser is made constant, and the heat sink is parallel to the end face via a spacer. A semiconductor light emitting device is described in which a transparent window is arranged, the semiconductor laser is sealed by the transparent window and a cap, and a lens is fixed to the transparent window by a transparent adhesive.

Japanese Unexamined Patent Publication No. 55-38064

In the semiconductor light emitting device disclosed in Patent Document 1, the lens is fixed to the transparent window by a transparent adhesive. In such a semiconductor light emitting device, the optical axis of the fixed lens may be tilted due to the variation in the thickness of the adhesive. Since the lens once fixed cannot be removed, the lens cannot be replaced.

An object of the present invention is to provide a semiconductor laser device and a method for manufacturing the same, in which the bonding condition of the lens is not affected by the adhesive and the lens can be removed and replaced when necessary.

In order to solve the above-mentioned problems, the method for manufacturing a semiconductor laser device according to an embodiment of the present invention includes a cap having an opening at a position corresponding to the front of the semiconductor laser element, and the semiconductor provided in the opening. It includes a sealing step of airtightly sealing the semiconductor laser element using a transparent plate that transmits a laser beam of the laser element, and a joining step of joining a lens to the transparent plate. The joining step is after the sealing step, and the joining in the joining step is a direct joining of the transparent plate and the lens.

The semiconductor laser apparatus according to another embodiment of the present invention includes a semiconductor laser element fixed to a substrate, a cap having an opening in front of the semiconductor laser element, and the semiconductor provided in the opening together with the cap. It includes a transparent plate that airtightly seals the laser element and transmits the laser beam of the semiconductor laser element, and a lens that is joined to the transparent plate to make the laser beam of the semiconductor laser element a substantially parallel beam. The bonding between the transparent plate and the lens is a direct bonding.

According to the present invention, it is possible to provide a semiconductor laser device and a method for manufacturing the same, in which the bonding state of the lens is not affected by the adhesive and the lens can be removed and replaced when necessary.

In addition, problems, configurations and effects other than those described above will be clarified by the following description of the embodiments.

It is a schematic diagram which shows the step in the manufacturing method of the semiconductor laser apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows the step in the manufacturing method of the semiconductor laser apparatus which concerns on other embodiment of this invention. It is a schematic diagram which shows the step in the manufacturing method of the semiconductor laser apparatus which concerns on other embodiment of this invention. It is a schematic diagram which shows an example of the semiconductor laser element used in this invention. It is a schematic diagram which shows another example of the semiconductor laser element used in this invention. It is a schematic diagram when the deformed laser diode bar is seen from the optical axis direction.

Hereinafter, the present invention will be described through embodiments of the invention based on the drawings.

FIG. 1 is a schematic diagram showing steps in a method for manufacturing a semiconductor laser device according to an embodiment of the present invention. It is assumed that the manufacturing process proceeds from the upper drawing to the lower drawing as indicated by the arrows. The manufacturing method of the present embodiment includes a sealing step of airtightly sealing a semiconductor laser device and a joining step of joining a lens to a transparent plate.

In the sealing step, the semiconductor laser element 106 is hermetically sealed using the cap 110 and the transparent plate 112. To specifically explain an example of airtight sealing, as shown in the upper drawing of FIG. 1, the semiconductor laser device 106 is bonded to the submount 104 arranged on the substrate 102 before the sealing step. The semiconductor laser device 106 can be used without particular limitation as long as it can oscillate a laser beam. For example, those having an emission peak wavelength of 300 nm to 500 nm, preferably 400 nm to 470 nm, and more preferably 420 nm to 470 nm can be used. Typically, an end face emission type semiconductor laser device can be used. The submount 104 is preferably made of a material having high thermal conductivity for heat dissipation of the semiconductor laser device 106. Specific examples thereof include AlN, CuW, diamond, SiC, and ceramics. Among them, the submount 104 is preferably made of single crystal AlN or SiC. On the other hand, a cap 110 having an opening 110a is prepared at a position corresponding to the front of the semiconductor laser element 106, and the transparent plate 112 is fixed to the opening 110a by a method such as fitting or joining. Then, as shown in the central drawing of FIG. 1, the semiconductor laser element 106 is hermetically sealed by using the integrated cap 110 and the transparent plate 112.

Here, "having an opening at a position corresponding to the front of the semiconductor laser element" means that the cap 110 is located exactly in front of the semiconductor laser element 106 so that the opening 110a of the cap 110 is located just in front of the semiconductor laser element 106 after airtight sealing. It means that the opening 110a is provided in the. The transparent plate 112 can transmit the laser beam of the semiconductor laser device 106.

In the joining step, as shown in the lower drawing of FIG. 1, the lens 114 is joined to the transparent plate 112 by direct joining. This joining step is performed after the sealing step. In the joining step, the lens 114 is joined to the transparent plate 112 along the optical axis of the semiconductor laser element 106. As a method of aligning the optical axes, for example, a laser profiler is used to take an intensity profile of the laser beam emitted by the semiconductor laser element 106, and the position of the light emitting portion of the semiconductor laser element 106 is specified from the center position of the intensity profile. And the optical axis can be aligned.

The method of direct joining may be optical contact. For example, using a transparent plate 112 and a lens 114 made of glass, quartz, sapphire, calcium fluoride, etc., the surface of the transparent plate 112 and the joint surface of the lens 114 to be bonded to each other are processed into a smooth flat surface by precision polishing. , The two are brought into close contact with each other at a temperature of 200 ° C. or lower and normal pressure. By this direct joining, the semiconductor laser device 100 as shown in the lower drawing of FIG. 1 is obtained. The materials of the transparent plate 112 and the lens 114 may be the same or different.

Since the melting temperature of the bonding material used to bond the semiconductor laser element 106 to the submount 104 and the bonding material used for airtight sealing is usually higher than 200 ° C, the lens bonding step should be at a temperature of 200 ° C or lower. If done, it will not destroy other joints. If the lens is joined under normal pressure, the airtight sealing state of the semiconductor laser device 106 will not be adversely affected.

In the manufacturing method of the present invention, since the lens 114 is bonded to the transparent plate 112 by direct bonding without using an adhesive, the lens optical axis is not tilted due to the variation in the thickness of the adhesive. Further, since the semiconductor laser device manufactured by the manufacturing method of the present invention does not use an adhesive for lens bonding, when deterioration occurs in the lens, the lens can be removed and replaced with a new lens. It can be easily realized. As a method of removing the lens, for example, there are a method of peeling the lens by tensile shear, a method of irradiating the inside of the lens with an ultrashort pulse laser to generate internal stress, and a method of peeling the lens.

Since the semiconductor laser device manufactured by the manufacturing method of the present invention does not use an adhesive for lens bonding, no light loss occurs due to the interfacial reflection of the adhesive. Further, since there is no refraction due to the adhesive, it is easy to design the optical system of the semiconductor laser device. Further, the adhesive is not deteriorated or deformed by absorbing the energy of the laser (particularly the short wavelength laser).

2 and 3 are schematic views showing steps in a method for manufacturing a semiconductor laser device according to another embodiment of the present invention. The embodiments shown in FIGS. 2 and 3 differ slightly from the embodiments shown in FIG. 1 in the detailed process in the sealing step.

In the embodiment shown in FIG. 2, as shown in the upper drawing, first, a cap 110 having an opening 110a at a position corresponding to the front of the semiconductor laser element 106 is joined to the substrate 102. Then, as shown in the central drawing, the transparent plate 112 is joined to the opening 110a of the cap 110, and the semiconductor laser element 106 is hermetically sealed using the cap 110 and the transparent plate 112. Further, as shown in the drawing below, the lens 114 is joined to the transparent plate 112 by direct joining in alignment with the optical axis of the semiconductor laser element 106. Therefore, the semiconductor laser device 100 can be obtained.

In the embodiment shown in FIG. 3, as shown in the upper drawing, the transparent plate 112 is first erected in front of the semiconductor laser element 106, and the transparent plate 112 is bonded to the substrate 102 with an adhesive or the like. Then, as shown in the central drawing, by joining the cap 110 having the opening 110a at the position corresponding to the transparent plate 112 to the substrate 102 and the transparent plate 112, the semiconductor laser is used by using the cap 110 and the transparent plate 112. The element 106 is hermetically sealed. Further, as shown in the drawing below, the lens 114 is joined to the transparent plate 112 by direct joining in alignment with the optical axis of the semiconductor laser element 106. Therefore, the semiconductor laser device 100 can be obtained.

FIG. 4 is a schematic diagram showing an example of a semiconductor laser device used in the present invention. As shown in FIG. 4, the semiconductor laser device 106 may be a single laser diode. In this case, there is one light emitting unit 202 on one end surface of the semiconductor laser device 106, from which a laser beam can be emitted as shown by a two-dot chain line. In the present specification, the direction in which the laser beam is emitted is the front of the semiconductor laser device. The above-mentioned "bonding the lens 114 to the transparent plate 112 in line with the optical axis of the semiconductor laser element 106" means the optical axis of the laser beam emitted from the light emitting portion 202 of the laser diode (in the present specification, the "laser diode". It means that the lens 114 is joined to the transparent plate 112 in accordance with the "optical axis" or "optical axis of the light emitting portion"). It is preferable that the semiconductor laser device 106 is arranged on the submount 104.

FIG. 5 is a schematic diagram showing another example of the semiconductor laser device used in the present invention. As shown in FIG. 5, the semiconductor laser device 106 may be a laser diode bar in which a plurality of laser diodes are arranged in a horizontal row. In this case, on one end surface of the semiconductor laser element 106, there are a plurality of light emitting units 202 corresponding to the number of laser diodes, and a laser beam is emitted from each light emitting unit 202 as shown by a two-point chain line. Can be done. When the semiconductor laser element 106 is a laser diode bar, in the joining step of the method for manufacturing a semiconductor laser device of the present invention, a lens corresponding to each laser diode is aligned with the optical axis of each laser diode in the laser diode bar. The 114 is joined to the transparent plate 112. The laser diode bar is preferably located on the submount 104. When the semiconductor laser element 106 is a laser diode bar, a lens array may be used as the lens 114.

FIG. 6 is a schematic view of the deformed laser diode bar when viewed from the optical axis direction. The semiconductor laser device 106 is usually bonded on the submount 104 by using a bonding material 402 such as solder. When the semiconductor laser element 106 is a laser diode bar, it is ideal that the height of each light emitting portion 202 of the laser diode bar is constant, but in reality, it accompanies the uniformity of bonding and heating / cooling. Due to the influence of thermal deformation and the like, the height of each light emitting portion 202 may vary by several microns. As shown in FIG. 6, a typical example is a deformation called "smile" in which the height of the light emitting portion 202 at the center of the laser diode bar is the highest and the height of the light emitting portions 202 at both ends is the lowest. Is.

For a laser diode bar having such a smile deformation, if the height of the optical axis of one light emitting unit 202 in the laser diode bar is adjusted, all the lenses 114 corresponding to each laser diode are the same. When joined to the transparent plate 112 at a height, most of the lenses deviate from the optical axis of the corresponding light emitting portion 202 except for the lenses whose optical axes match the height. The laser beam that has passed through such a lens will be inclined and propagated off the optical axis of the lens.

According to the manufacturing method of the present invention, the lens 114 corresponding to each laser diode is joined to the transparent plate 112 according to the optical axis of each laser diode in the laser diode bar, so that the inclination of the laser beam due to the misalignment of the optical axis is obtained. Can be prevented. When a lens array is used as the lens 114, a lens array may be manufactured so that a lens corresponding to the optical axis of each laser diode in the laser diode bar is fitted, and the lens array may be bonded to the transparent plate 112.

On the other hand, the lower drawings in FIGS. 1, 2 and 3 are also examples of the embodiment of the semiconductor laser device of the present invention. As shown in these drawings, the semiconductor laser device 100 includes a semiconductor laser element 106, a cap 110, a transparent plate 112, and a lens 114. The semiconductor laser device 106 is fixed to the substrate 102 via the submount 104. The cap 110 has an opening 110a in front of the semiconductor laser element 106, and a transparent plate 112 is provided in the opening 110a. The semiconductor laser device 106 is hermetically sealed by a cap 110 and a transparent plate 112. The lens 114 is joined to the transparent plate 112 by direct joining. The transparent plate 112 transmits a laser beam emitted from the semiconductor laser device 106, and the lens 114 can make the laser beam a substantially parallel beam.

Since the lens 114 is directly bonded to the transparent plate 112, the lens optical axis does not tilt due to variations in the thickness of the adhesive. Since no adhesive is used for lens bonding, it is possible to easily remove the lens and replace it with a new lens when the lens deteriorates. Further, since no adhesive is used between the lens 114 and the transparent plate 112, no light loss occurs due to the interfacial reflection of the adhesive. Since there is no refraction due to the adhesive, it is easy to design the optical system of the semiconductor laser device. Further, the adhesive does not deteriorate or deform due to the absorption of energy of the laser (particularly the short wavelength laser). When joining a plurality of lenses corresponding to a laser diode bar, when using an adhesive, it is extremely difficult to control the application of the adhesive evenly to each lens. Since the present invention does not use an adhesive, such management is unnecessary and even adhesion can be realized.

As shown in FIGS. 4 and 5, the semiconductor laser device 106 may be a single laser diode, or may be a laser diode bar in which a plurality of laser diodes are arranged in a horizontal row. When the semiconductor laser element 106 is a laser diode bar, a lens 114 corresponding to each laser diode is bonded to the transparent plate 112 in accordance with the optical axis of each laser diode in the laser diode bar. Therefore, it is possible to prevent the laser beam from being tilted due to the deviation of the optical axis.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add or replace a part of the configuration of each embodiment with another configuration.

100 Semiconductor laser device 102 Substrate 104 Submount 106 Semiconductor laser element 110 Cap 110a Opening 112 Transparent plate 114 Lens 202 Light emitting part 402 Joint material

Claims (5)

A seal that airtightly seals the semiconductor laser element by using a cap having an opening at a position corresponding to the front of the semiconductor laser element and a transparent plate provided in the opening through which the laser beam of the semiconductor laser element is transmitted. Stop step and
The joining step of joining the lens to the transparent plate,
In the method of manufacturing a semiconductor laser device including
The joining step is after the sealing step and
A method for manufacturing a semiconductor laser apparatus, wherein the joining in the joining step is a direct joining between the transparent plate and the lens. In the method for manufacturing a semiconductor laser device according to claim 1,
The method for manufacturing a semiconductor laser device, characterized in that the direct joining is an optical contact. In the method for manufacturing a semiconductor laser device according to claim 1 or 2.
The semiconductor laser element is a laser diode bar.
A method for manufacturing a semiconductor laser apparatus, which comprises joining the lens corresponding to each laser diode to the transparent plate in the joining step according to the optical axis of each laser diode in the laser diode bar. The method for manufacturing a semiconductor laser device according to any one of claims 1 to 3, wherein the direct joining is performed at normal pressure. The semiconductor according to any one of claims 1 to 4, wherein the material of the transparent plate and the lens is at least one selected from the group consisting of glass, quartz, sapphire, and calcium fluoride. How to manufacture a laser device.

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