JPH08264883A - Semiconductor laser module and manufacture thereof - Google Patents

Abstract

PURPOSE: To reduce the number of assembly steps of a semiconductor laser module by integrating a laser beam converging lens with a semiconductor mounting substrate in the semiconductor laser module structure. CONSTITUTION: A semiconductor laser module comprises a semiconductor device 4 having electrodes 4a, 4b at the opposed front and rear surfaces and a light emitting region 4c near the center of the lateral surface of a thickness directional intermediate area, an electrode 35 having a groove of the size mounted with the device 4 at the one side ridge area of the surface, and a semiconductor device mounting substrate 3' with a lens formed with a lens part 31b protruding from the rear surface at the predetermined position corresponding to the semiconductor mounting position of the rear surface. The electrode 4b corresponding to the electrode is opposed to the electrode 35 in the groove of the substrate 3' with the lens, and the device 4 in which the region 4c is directed to the lens part 31b side is mounted at the electrode 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser module for converging or collimating a laser beam emitted from a laser diode (hereinafter referred to as LD) as a semiconductor device in a diffused state and coupling it to an optical fiber. In particular, a semiconductor laser module in which a lens portion for converging or collimating a laser beam is integrally formed with a base body on which the LD is positioned and mounted to improve productivity by reducing the number of assembly steps as a module. The manufacturing method is related.

A module for coupling an LD with an optical fiber, an optical waveguide, or the like is being demanded to be further reduced in cost as its application to optical transmission and high-speed data transmission is increased. However, because of the current situation where adjustments such as the arrangement position of the lens system with respect to the LD and optical axis alignment are made, how to reduce the man-hours of these is a major issue.

[0003]

2. Description of the Related Art FIG. 4 is a schematic diagram showing a configuration example of a conventional semiconductor laser module. Referring to FIG. 4, which is a cross-sectional view of a main part according to the present invention taken along a plane along the optical axis, a semiconductor laser module 2 has a cylindrical case 21 with a bottom for accommodating and housing an LD package 1 in which an LD is packaged. lens
A lens holder 23 that can be inserted into the inner diameter portion of the case 21 in a state where 22 is positioned and held, and a flanged pipe that is fixed to the end surface of the lens holder 23 and positions the optical fiber 25.
It is composed mainly of 24 etc.

In this case, in order to converge or collimate the laser light emitted from the LD package 1 in a diffused state efficiently and efficiently, at least the optical axis of the laser light and the central axis of the lens holder 23, and hence the sphere, are used. In order to ensure the axial alignment with the center of the lens 22 and at the same time to efficiently enter the laser light emitted in a diffused state into the spherical lens 22, it is necessary to perform a reliable alignment in the optical axis direction. Are adjusted in the three-dimensional directions of X, Y, and Z to be fixed on the upper surface (the right side surface in the figure) of the LD package 1.

[0005]

However, in such a semiconductor laser module 2, the LD package 1 and the spherical lens are used.
Since the lens holder 23 that holds 22 is a separate component, a special technique is required to adjust the above-mentioned lens holder 23 in the three-dimensional direction with respect to the LD package 1, resulting in assembly and adjustment as a module. There is a problem that it takes a lot of man-hours and cannot expect improvement in productivity.

[0006]

The above problem is a semiconductor laser module that allows a laser beam emitted from a semiconductor device to enter an optical fiber. With a lens having the above semiconductor device that emits laser light in the height direction from a light emitting region provided near the center of the surface in the width direction, and a groove having a groove formed on the front surface of the silicon substrate material and a lens portion formed on the back surface. A groove for the semiconductor device mounting substrate with a lens, the width of which is substantially equal to the width of the semiconductor device, the depth of which is substantially equal to the height of the semiconductor device, and the longitudinal length of the semiconductor device. The electrode having a length and extending to the surface of the silicon substrate material formed on the wall surface in the lengthwise direction of the groove is in contact with the electrode of the semiconductor device corresponding to the electrode. The semiconductor device so that the laser beam is emitted is mounted on the lens unit side, the lens portion is solved by a semiconductor laser module which is formed at a position corresponding to the emitted light of the semiconductor device.

In the method of manufacturing a semiconductor laser module according to claim 1, a width substantially equal to the width of the semiconductor device according to claim 1 and a length in the front-rear direction of the semiconductor device are provided on one surface of the silicon substrate. Forming a square hole having a length of more than twice the length and a depth corresponding to the height of the semiconductor device, and forming a square hole on the back surface of the silicon substrate in the vicinity of each position corresponding to the wall surfaces on both sides in the longitudinal direction of the square hole. A step of forming a lens portion projecting from the back surface at a predetermined position, a step of forming electrodes extending to the front surface on the wall surfaces on both sides in the longitudinal direction of each of the square holes, and the silicon substrate having the electrodes formed thereon, At least a step of forming a semiconductor device mounting board with a lens by cutting in the width direction passing through the vicinity of the longitudinal center point of each of the square holes, and the semiconductor on each electrode located on the wall surface of the lens-equipped semiconductor device mounting board. Equipment Step electrodes corresponding to the electrodes of the semiconductor device mounting substrate with serial lens facing to the light emitting point is implemented disposed such that the lens unit side, is solved by the method for manufacturing a semiconductor laser module including a.

[0008]

When the lens part for converging or collimating the laser light without waste is integrally formed with the substrate for positioning and attaching the LD, the adjustment of the optical axis of the laser light and the center of the lens part over the three-dimensional direction. Can be eliminated.

Therefore, according to the present invention, a concave hole having a wall surface with a width and a depth such that the LD can be attached to the entire surface of the P electrode is formed on one surface of the (110) silicon substrate, and a light emitting region (light emitting region) is formed. Point) faces the other surface of the silicon substrate and converges or collimates the laser light from the LD on a region on the other surface of the silicon substrate corresponding to the light emitting point of the LD attached to the wall surface. The required semiconductor laser module is constructed by using the substrate on which the obtained convex lens portion is formed.

This means that the wall surface of the concave hole, which serves as the attachment portion of the LD in the substrate, and the lens portion are integrally formed. Therefore, the LD emission point after attachment, that is, the laser light optical axis and the lens portion are formed. Means to be matched without adjustment.

Therefore, the position adjustment work between the optical axis of the laser beam and the center of the spherical lens, which is at least required in the conventional semiconductor laser module, can be eliminated together with mechanical members such as a lens holder, and the number of assembly steps as a module is increased. It can be expected that productivity will be improved by reducing the number of parts and materials.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram (No. 1) for explaining a semiconductor laser module of the present invention together with a manufacturing method, and FIG. 2 is a diagram (No. 2) for explaining a semiconductor laser module of the present invention together with a manufacturing method. is there.

FIG. 3 is a diagram for explaining another embodiment. First, the semiconductor laser module 3 according to the present invention will be described step by step with reference to FIGS.

FIG. 1A is a cross-sectional view of the (110) silicon substrate 31 shown in the perspective view (1 ') taken along arrows a to a', the surface of which is an oxide film formed by a conventional thermal oxidation technique. (SiO ₂ )
It is coated with 32 to a thickness of, for example, about 2 μm.

Therefore, an LD whose width will be described later is formed on the oxide film 32.
The width a _{1 of the} LD 4 is approximately equal to the width b ₁ and the length is ₂ of the thickness a ₂ of the LD 4.
After patterning a regular positive resist so that the square windows that are more than double b ₂ are aligned, for example carbon tetrafluoride
When dry etching is performed with a gas such as (CF ₄ ), it is etched away as the region window pattern 32a of the oxide film 32 exposed from the above-mentioned window, and therefore the state shown in (2) can be obtained by removing the positive resist. it can.

Then, for example, "ethylenediamine + pyrocatechol + water [NH ₂ (CH ₂ ) ₂ NH ₂ + C ₆ H ₄ (OH) ₂ + H ₂ O]"
When a surface of the silicon substrate exposed from the oxide film 32 is etched to a depth b ₃ approximately equal to the height a _{3 of the} LD 4 by using a surface selective etching solution as shown in FIG. 31a can be dug, so the above oxide film
32 is removed with, for example, hydrofluoric acid (F) to obtain the state shown in (3).

(3 ') is a perspective view showing the state at this time. On the other hand, a method for forming a lens portion projecting from the surface of the silicon substrate is described in, for example, "Institute of Electronics, Information and Communication Engineers, IEICE Technical Report, OQE 92-173 (1993-02), pages 43 to 48". It can be realized by using a known technique.

That is, first, a photoresist 33 is circularly patterned and formed in the vicinity of the wall surfaces at both ends in the length direction of the hole 31a on the back surface side of the silicon substrate by a normal photolithography technique to obtain the state shown in (4).

Therefore, the photoresist forming area is set to, for example, 2
When the photoresist 33 is melted by heating to about 00 ° C., the surface tension of the photoresist 33 causes the hemispherical projections 33 to be formed.
Form a and enter the state shown in (5).

Next, when the surface of the silicon substrate is uniformly etched by ordinary ion beam etching, the lens portion 31b having a shape substantially equal to the hemispherical projection 33a of the photoresist 33 can be transferred onto the surface of the substrate (6). Can be in the state of.

(6 ') is a perspective view showing the state at this time. In this case, the center line (optical axis) of the lens part 31b 31
In order to correspond to LD4, c is set so as to be located a predetermined distance "c" described later from the longitudinal end face 31a 'of the rectangular hole 31a as shown in the enlarged view (6 ") in the garden.

Next, a thickness of 2300Å is applied to the entire surface of the silicon substrate.
After forming an oxide film (SiO ₂ ) to a certain extent, as shown in FIG. 2 (7), a vapor deposition mask 34 having a window 34a in which only one end face 31a ' _{-1 in} the longitudinal direction of each hole 31a can be exposed is formed. An electrode 35 _-1 made of titanium (Ti), gold (Au) or the like is patterned on the one end face 31a ' _-1 and a part of the surface by a normal oblique vapor deposition technique with an angle α.

Subsequently, the same electrode _35-2 as described above is patterned on the other wall surfaces 31a'- _{2 in} the longitudinal direction of each of the square holes 31a and a part of the surface by the oblique deposition technique in the opposite direction by the same deposition mask 34. The state becomes (8).

Therefore, the silicon substrate 31 is formed by, for example, a dicing saw with a line A ₁ connecting the center points of the square holes 31a in the longitudinal direction and a line A ₂ connecting the center points of adjacent square holes in the longitudinal direction. The semiconductor device mounting substrate 3'with a lens can be obtained by cutting the substrate with a lens or the like to separate it as shown in the perspective view of (9).

On the other hand, the LD 4 attached to each of the electrodes 35 _-1 , 35 _-2 has a size of width a ₁ , length in the front-rear direction (hereinafter referred to as thickness) a ₂ and height a ₃ as described above. It has a plate shape having an N electrode 4a on one surface and a P electrode 4b on the other surface, and a light emitting point 4c is provided on the P electrode side at the center of the upper surface in the figure.

The lens unit 31 described in (6 ") of FIG.
The distance "c" between the center line 31c of b and the end face 31a 'in the longitudinal direction of the hole 31a is defined by the thickness of each of the electrode electrodes 35 _-1 , 35 _-2 as c ₁ and the P electrode of the light emitting point 4c of the LD 4 described above. It is set to satisfy "c = c ₁ + c ₂ " when the distance from the surface is c ₂ .

Therefore, the P electrode 4b of the LD 4 is the electrode 35
_-1 or 35 _-2 , the semiconductor laser with the LD4 mounted as shown in (10) is formed by connecting it in the inverted state as shown by the arrow B in the figure by, for example, a thermal bonding technique at 300 ° C. -The module 3 can be obtained in an aligned state.

In this semiconductor laser module 3,
Since the width a ₁ and a width b ₁ of the substrate rectangular hole 31a of the LD4 is substantially equal correspondence easily center of the lens portion 31b described above and the light emitting point 4c of the LD4 the positioning to be implemented without paying special attention Since the substrate side electrode 35 and LD4 P
By applying a predetermined potential between the electrode 4b and the electrode 4b, the laser light emitted from the light emitting point 4c of the LD 4 can be used without waste.
The laser beam can be made incident on the laser beam and the laser beam can be efficiently converged or collimated.

Although the semiconductor laser module shown in FIG. 2 (10) is shown as being arrayed so as to be compatible with a plurality of optical fibers, the semiconductor laser module 2 explained in FIG. When it corresponds to one optical fiber like
Since the modules can be dealt with by cutting and separating them into individual modules 3, there is an advantage that a plurality of semiconductor laser modules 3 can be collectively formed.

FIG. 3 showing another embodiment shows a known technique described in, for example, "Magazine" Optical Technology Contact "published by Japan Optomechatronics Association, Vol.30. No12 (1992), pages 15-22". It shows a case where a required semiconductor laser module is constructed by using a flat plate microlens based on the above.

That is, in FIG. 3, the semiconductor laser in this case
The module is a substrate 51 in which a silicon substrate 52 formed by using the (110) silicon substrate 31 described in FIG. 1 by using the processing technique in FIG. 1 and the above-described flat plate microlens 53 are bonded and integrated.
Is configured as a base.

First, (3-1) of FIG. 3 is the same as (1) of FIG. 1 and the (110) silicon substrate 31 whose surface is covered with an oxide film (SiO ₂ ) 32.
Is. Therefore, the window pattern 32a is formed on the oxide film (SiO ₂ ) 32 through the process described in FIG. 1 (2) to form (3-2) in FIG.
The state is shown in.

Then, the area of the substrate exposed from the window pattern 32a is removed by etching with a surface-selective etching solution such as ethylenediamine / pyrocatechol described above until the thickness direction disappears, and the square hole 31a described in FIG. 1 is removed. It is possible to obtain the silicon substrate 52, which is changed to the penetrating square hole 52a, as shown in (3-3).

On the other hand, (3-1) 'in the figure is the same as the photoresist 33 shown in FIG. 1 after the metal mask 53a is formed on the surface of the transparent glass substrate 53' by means of vapor deposition or the like and then by the ordinary photolithography technique. Around the same size in position 53
a'is provided.

Then, the substrate 53 'is made of, for example, thallium nitrate.
By performing ion exchange when immersed in a molten salt such as (TlNO ₃ ), a hemispherical lens effect region 53 ″ as shown in (3-2) ′ can be formed only in the vicinity of the opening 53a ′.

Therefore, by peeling off the metal mask 53a after that, the flat plate microlens 53 having the lens effect area 53 ″ at the same position as the lens portion 31b in FIG.
It can be formed as shown in 3) ′.

Therefore, a UV curable adhesive is applied to each of the lens effect areas 53 "and the square holes 52a at positions corresponding to each other so that the back surface (lower surface in the figure) side of the flat plate microlens 53 is in contact with the silicon substrate 52. By bonding and integrating with, etc.,
The substrate 51 shown in (3-4) can be constructed.

Even if the UV-curable adhesive in this case is bonded by thermocompression bonding at about 1100 ° C., the same substrate
You can get 51. And the lens effect range in this case
53 ″ center line (optical axis) and the end face 52a ′ in the longitudinal direction of the square hole
The fact that there is a “c” gap between and means that it is (6 ″) in FIG.
Is the same as

In the above-mentioned substrate 51, the (110) silicon substrate 31 shown in (3-1) of FIG. 3 and the flat plate microlens 53 shown in (3-3) 'of FIG. 3 are bonded by the above means. After that,
An oxide film (SiO ₂ ) 32 having a window pattern 32a is formed on the surface of the (110) silicon substrate 31 in the step described in (2), and
The exposed area of the (110) silicon substrate 31 can also be obtained by etching away with an etchant having surface selectivity until the thickness of the silicon substrate 31 is reduced.

Next, after the steps described in (7) and (8) of FIG. 2 are performed, the LD 4 shown in FIG. 1 is attached to the substrate 51 by a conductive adhesive as indicated by arrow C as in (9) of FIG. Etc.
Further, by cutting along the lines A ₁ and A ₂ described in FIG.
The required semiconductor laser module 5 mounted with (3-
5) can be obtained.

In such a semiconductor laser module 5,
Since there is no opaque area of the silicon substrate between the LD4 mounting position and the lens effect area 53 ″, for example, L that emits visible light
There is a merit that it can be applied to a semiconductor device that emits light having a wavelength close to that of ED and visible light.

[0042]

As described above, according to the present invention, the lens portion for converging or collimating the laser beam is integrally formed with the substrate for positioning and adhering the LD, thereby reducing the man-hours for assembling the module to improve productivity. An improved semiconductor laser module and a method of manufacturing the same can be provided.

[Brief description of drawings]

FIG. 1 is a diagram (No. 1) for explaining the semiconductor laser module of the present invention together with the manufacturing method.

FIG. 2 is a diagram (No. 2) for explaining the semiconductor laser module of the present invention together with the manufacturing method.

FIG. 3 is a diagram illustrating another embodiment.

FIG. 4 is a schematic diagram showing a configuration example of a conventional semiconductor laser module.

[Explanation of symbols]

3,5 Semiconductor laser module 3 ', 51 Semiconductor device mounting board with lens 4 Laser diode 4a N electrode 4b P
Electrode 4c Light emitting area (light emitting point) 31,52 (110) Silicon substrate 31a, 52a Square hole 31a ', 31a' _-1 , 31, a '
_-2 , 52a 'Wall surface 31b Lens part 31c Center line (optical axis) 32 Oxide film 32a Window pattern 33 Photoresist 33a Hemispherical protrusion 34 Evaporation mask 34a Window 35, 35 _-1 , 35 _-2 Electrode 51 Semiconductor device with lens mounted Substrate 53 Flat microlens 53 ′ Glass substrate 53 ″ Lens effect area 53a Metal mask 53a ′ Aperture

Claims (3)

[Claims] 1. A semiconductor laser module for allowing a laser beam emitted from a semiconductor device to enter an optical fiber, wherein electrodes are provided on the front and rear surfaces facing back, and the electrodes are provided in the vicinity of the central portion in the width direction surface of the front-rear intermediate region. The semiconductor device emitting laser light in the height direction from the light emitting region, and a lens-equipped semiconductor device mounting substrate having a groove formed on the front surface of the silicon substrate material and a lens portion formed on the back surface, The groove of the semiconductor device mounting board with lens has a width substantially equal to the width of the semiconductor device, a depth substantially equal to the height of the semiconductor device, and a length exceeding the length in the front-rear direction of the semiconductor device. The laser beam is formed on the lens portion side so that the electrode extending to the surface of the silicon substrate material formed on the wall surface in the length direction of the semiconductor device contacts the electrode of the semiconductor device corresponding to the electrode. Is the semiconductor device is implemented to output, semiconductor laser module in which the lens unit is characterized in that it is formed at a position corresponding to the emitted light of the semiconductor device. 2. The lens-equipped semiconductor device mounting board according to claim 1, which has a block shape having a thickness exceeding the height of the semiconductor device and extends to one side while maintaining a width substantially equal to the width of the semiconductor device. A silicon substrate in which a notch is formed with a length exceeding the length in the front-rear direction of the semiconductor device, and an electrode extending to the surface is formed on a wall surface of the deepest part of the notch, and the notch of the silicon substrate. A semiconductor laser module, comprising: a flat plate microlens in which a lens portion is embedded at a predetermined position on the back surface near each position corresponding to the innermost wall surface. 3. The method for manufacturing a semiconductor laser module according to claim 1, wherein a width substantially equal to the width of the semiconductor device according to claim 1 and a length in the front-rear direction of the semiconductor device are provided on one surface of the silicon substrate. Of 2
A step of forming a square hole having a length more than double and a depth corresponding to the height of the semiconductor device, and a predetermined position near each position corresponding to the wall surfaces on both sides in the longitudinal direction of the square hole on the back surface of the silicon substrate A step of forming a lens portion protruding from the back surface, a step of forming electrodes extending to the front surface on the wall surfaces on both sides in the longitudinal direction of each of the square holes, and at least the silicon substrate having the electrodes formed thereon, A step of forming a semiconductor device mounting board with a lens by cutting in the width direction passing through the vicinity of the center point in the longitudinal direction of each square hole, and the above semiconductor device on each electrode located on the wall surface of the semiconductor device mounting board with a lens. A method of manufacturing a semiconductor laser module, comprising a step of arranging and mounting an electrode corresponding to an electrode of the semiconductor device mounting board with a lens facing each other so that a light emitting point faces a lens part side.