JP5861482B2 - Optical module manufacturing apparatus and manufacturing method - Google Patents

Description

  The present invention relates to a manufacturing apparatus and a manufacturing method of an optical waveguide module used for optical communication, in particular, wavelength division multiplexing transmission.

  In recent years, downsizing of optical modules has been demanded for the purpose of speeding up and power saving. Accordingly, in the manufacture of optical modules, there is a demand for accuracy that the optical axis of optical elements such as optical waveguides and laser diodes (LD) is 1 μm or less.

  However, the thickness of the LD has a variation of about 20 μm compared with the optical axis alignment accuracy (1 μm). For this reason, when manufacturing an optical module that is mounted on an optical waveguide substrate with the active layer side surface of the LD facing up, the mounting height of the LD is required to align the optical axes of the optical waveguide and the LD. It was necessary to adjust the process. In this process, since the amount of light incident on the optical waveguide is measured while the LD is energized to emit light, the optical axis of the optical waveguide and the LD is aligned, which is laborious and extremely poor in productivity.

  As a workaround for the process of aligning the optical axis, the surface on the active layer side of the LD is placed on a support stand set so that the optical axis of the optical waveguide of the optical waveguide substrate and the optical axis of the active layer of the LD coincide. There is a method of aligning the optical axis in the height direction in a state of being directed to (see Patent Document 1 FIG. 1). This method uses the fact that the reference surface on the active layer side of the LD and the optical axis height of the active layer can be accurately manufactured without error, and the height reference surface of the LD is brought into contact with the height-set support base. The height position is adjusted with.

  However, the method of Patent Document 1 has a configuration in which the active layer electrode portion of the LD is joined by soldering, which may deteriorate the product yield. This is because when a stress sensitive LD such as a distributed feedback semiconductor laser having a diffraction grating provided on the active layer is used, residual stress concentrates on the solder joint and wavelength characteristics deteriorate. Moreover, in the method of Patent Document 1, it is necessary to separately align the optical axis in the horizontal direction. Therefore, the LD requires a special specification in which a mark for infrared transmission recognition is formed. (FIG. 1 of Patent Document 2).

  As another conventional technique, a manufacturing method in which a tray for using a surface far from the ceramic substrate as a reference is used for batch mounting is disclosed. However, the external accuracy of the LD is less than the allowable optical axis deviation. In this method, it is extremely difficult to manufacture the optical waveguide and the optical axis of the LD with an accuracy of 1 μm or less. (See FIG. 6 of Patent Document 3.)

Japanese Patent No. 2976642 JP 2000-231041 A JP 2001-141951 A

  The object of the present invention is to solve such drawbacks, and this time, in an optical module that is becoming more and more accurate, a manufacturing apparatus and a manufacturing device that are highly productive without causing deterioration of the characteristics of the LD. It is to provide a method.

  In order to solve the above problems, an optical module manufacturing apparatus of the present invention is an optical module manufacturing apparatus for mounting an optical element on a substrate, and the surface of the substrate on which the optical waveguide is formed is oriented vertically upward A mounting stage, a mounting arm that holds the surface of the optical element on the active layer side in a vertically upward direction, an XY axis stage that transfers the mounting arm to any horizontal position, and a mounting arm. A Z-axis stage that moves to an arbitrary position in the vertical direction, and an image measurement processing device that photographs the mounting area of the optical element on the substrate and measures the mounting area, and the mounting arm is a glass arm with a projection And holding the optical element on the glass arm through the protrusion, aligning the optical axis of the optical element formed on the substrate with the active layer of the optical element close to each other, and aligning the optical axis of the optical waveguide on the substrate. And the glass door The lower surface of the arm is mounted the optical element to the substrate at a position in contact.

  In the above optical module manufacturing apparatus, the height of the projection of the glass arm is such that the height reference plane of the optical element and the upper surface of the optical waveguide of the substrate are surfaces on which the distance between the active layer and the active layer can be accurately formed. The optical axis height of the optical waveguide and the optical axis height of the optical element active layer coincide with each other when the upper surface of the optical waveguide and the lower surface of the glass arm are in contact with each other. Yes.

  In the above optical module manufacturing apparatus, the height of the projection of the glass arm is such that the height reference plane of the optical element, which is a plane on which the distance in the height direction from the active layer can be accurately formed, and the optical waveguide of the substrate The height is larger than the step between the upper surface and the optical axis height of the optical waveguide and the optical axis height of the optical element active layer are set to coincide with each other with the glass arm inclined.

  In the above optical module manufacturing apparatus, the protrusions of the glass arm are located outside the electrodes and wirings formed on the active layer of the optical element, and are disposed at locations facing the surface corresponding to the LD height reference surface. ing.

  In order to solve the above problems, an optical module manufacturing method according to the present invention is an optical module manufacturing method in which an optical element is mounted on a substrate, and the surface of the substrate on which the optical waveguide is formed is directed vertically upward. Holding the substrate on the mounting stage while holding the substrate, holding the optical element on the mounting arm via a glass arm with a projection with the active layer side surface of the optical element facing vertically upward, and mounting Moving the arm horizontally and vertically to bring the optical element close to the substrate; bringing the end face of the optical waveguide of the substrate close to the optical element to align the optical axis; and the upper surface of the optical waveguide of the substrate; A step of mounting the optical element at a position where the lower surface of the glass arm contacts.

  The present invention realizes an optical module manufacturing apparatus and manufacturing method with high productivity that can match the optical axis height of the optical waveguide and the optical axis height of the LD active layer without any special adjustment.

It is a side view of the optical module manufacturing apparatus which concerns on the 1st Example of this invention. It is sectional drawing of the optical module when LD is mounted in the optical waveguide board | substrate. It is the top view and side view by the side of the active layer of LD which is a component of an optical module. It is a figure which shows the optical module manufacturing method of 1st Embodiment. It is a figure which shows the optical module manufacturing method of 1st Embodiment. It is a figure which shows the optical module manufacturing method of 1st Embodiment. It is a figure which shows the optical module manufacturing method of 1st Embodiment. It is a figure which shows the optical module manufacturing method of 1st Embodiment. It is a figure which shows the optical module manufacturing method of 1st Embodiment. It is a flowchart which shows a manufacture procedure. It is a figure which shows the optical module manufacturing method of 2nd Embodiment. It is a figure which shows the optical module manufacturing method of 3rd Embodiment. It is a figure which shows the optical module manufacturing method of 4th Embodiment.

[First Embodiment]
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an optical module manufacturing apparatus as a first embodiment of the present invention.
An optical module manufacturing apparatus 1 shown in FIG. 1 is used when mounting an edge-emitting LD in an LD mounting region.

  This optical module manufacturing apparatus 1 includes a heating mounting stage 3 on which an optical waveguide substrate 21 is mounted, a mounting arm 4 on which an LD is mounted, an XY axis stage 5 and a Z axis stage 6 for moving the mounting arm 4, and image recognition optics. A system 7 and main control means (not shown) for driving and controlling each operation are provided.

  The heating stage 3 has a function of heating the optical waveguide substrate 21 in a state where the optical waveguide substrate 21 is held by suction. The θz axis stage 8 is equipped with a heating stage 3. The θz axis stage 8 rotates and moves the heating stage 3 with the vertical z direction as the central axis for horizontal position adjustment.

  The image recognition optical system 7 photographs the LD mounting area on the optical waveguide substrate 21. The image measurement processing device 2 measures the mounting region from the captured image, and measures the horizontal position between the optical waveguide and the active layer electrode of the LD.

  The mounting arm 4 adsorbs and holds the LD with the surface of the active layer side of the LD facing upward in the vertical direction.

  A glass arm 17 having a protrusion at the tip is held and fixed to the mounting arm 4. The mounting arm 4 is fixed to the Z-axis stage 6 via a Z-axis fine movement unit 10 composed of parallel leaf springs 9.

  The Z-axis vertical movement range of the mounting arm 4 is restrained by the upper stopper 11 and the lower stopper 12, and the coil of the voice coil motor 13 for adjusting the mounting load of the LD is fixed to the mounting arm 4. The displacement of the mounting arm 4 in the Z-axis direction is measured by the displacement sensor 14.

  The XY axis stage 5 moves the mounting arm 4 to an arbitrary position on the XY plane. The Z-axis stage 6 moves the mounting arm 4 to an arbitrary position in the vertical direction. The Z-axis stage 6 is mounted on the XY-axis stage 5 via the θy-axis stage 15. The θy axis stage 15 rotates and moves the mounting arm 4 with the y direction as the central axis for height inclination adjustment. The θx axis stage 16 rotates and moves the mounting arm 4 with the x direction as the central axis for height inclination adjustment.

  FIG. 2 is a cross-sectional view showing the optical module and the glass arm tip 17 when the LD 19 is mounted on the optical waveguide substrate 21.

  The optical module 20 includes an optical waveguide substrate 21, an optical waveguide 22 provided on a part of the optical waveguide substrate, and an LD mounting provided on another part of the optical waveguide substrate corresponding to the optical waveguide 22. Region 23.

  An LD height reference surface 24 is defined as a surface provided on a part of the surface of the LD 19 on the active layer side and capable of forming an accurate distance (thickness) in the height direction from the active layer. In general, the height from the optical axis 25 of the optical waveguide to the optical waveguide upper surface 26 is larger than the height of the LD active layer 25 from the optical axis 25 of the LD active layer. Therefore, when the LD 19 is mounted on the LD mounting region 23 of the optical waveguide substrate 21 with the optical axis aligned, the LD height reference plane 24 is lower than the optical waveguide upper surface 25.

  The main control means controls each operation of the optical module manufacturing apparatus 1, aligns the optical waveguide 22 with the active layer electrode of the LD 24, and then mounts the LD 19 in the LD mounting region 23.

  A glass arm 17 is held and fixed to the mounting arm 4. The glass arm 17 has a tip portion in which an adsorption hole 18 having a diameter of about 0.1 mm for adsorbing an LD is formed. The glass arm distal end portion 17 is formed by joining a plurality of quartz glass plates on which suction channels are formed by electrostatic bonding (anodic bonding). The mounting arm 4 has a flow path for vacuum-sucking the LD 19, and the flow path is connected to the vacuum source by piping. Since the LD 19 and the optical waveguide substrate 21 are observed by the CCD camera (image recognition optical system 7) through the glass arm 17, the material of the glass arm 17 is preferably a transparent member such as quartz glass.

  Therefore, in the present embodiment, a protrusion 27 having a thickness equal to the distance between the optical waveguide upper surface 25 and the LD height reference surface 24 is installed at the tip of the glass arm 17. When the LD 19 is adsorbed to the glass arm 17 through the projection 27, the height of the lower surface (glass arm reference surface 28) of the glass arm 17 on which no projection is formed and the upper surface 26 of the optical waveguide are substantially parallel to each other. The optical axis height of the optical waveguide matches the optical axis height of the LD active layer.

  FIG. 3 shows a plan view and a side view of the active layer side of the LD which is a component of the optical module.

The optical axis height of the active layer 32 of the LD 19 is about 2 to 4 μm from the LD height reference plane, and the variation is sufficiently smaller than the allowable optical axis deviation of 0.3 to 1 μm. On the other hand, the variation in the thickness of the active layer electrode 30 and the wiring electrode 31 of the LD is about 2 to 5 μm, which is larger than the allowable optical axis deviation. Therefore, the shape of the protrusion is set so that the protrusion of the glass arm 17 contacts the LD height reference surface 24 in a state where the electrode surface is avoided. In the present embodiment, the projections of the glass arm are formed on the outside of the wiring electrode and the active layer electrode and at a location facing the surface corresponding to the LD height reference surface. (See Figure 5)
As shown in FIG. 4, the protrusion 27 of the glass arm 17 has a shape corresponding to the LD height reference plane 24 and not in contact with the wiring electrode 30 of the LD. The protrusion 27 is disposed at a location corresponding to the surface corresponding to the LD height reference surface 24 outside the wiring electrode 30. The height of the protrusion is about 10 μm, and like the glass arm 17, the material is preferably a transparent member such as quartz glass. As a method of forming the protrusion, the protrusion is formed by wet etching treatment of glass or the like.

  As described above, a glass arm having a protrusion having a thickness equal to the distance between the upper surface of the optical waveguide and the LD height reference surface is used, and the LD is in a state where the height of the glass arm reference surface and the upper surface of the optical waveguide coincide. Can be matched to the height of the optical axis without adjustment.

  The LD 19 is fixed on the optical waveguide substrate 21 with a bonding material 29 with the active layer surface facing upward. The bonding material uses AuSn solder, but is not limited to this. Solder such as AuSi, SnSb, SnAg, SnAgCu, conductive adhesive such as Ag paste, Ag nanoparticle paste, Au submicron particle paste But you can. In order for the adhesive layer to absorb the thickness variation of the LD, the bonding material preferably has a viscosity that allows the bonding layer to have a thickness.

  Next, the optical module manufacturing method of the first embodiment will be described with reference to FIG. 1 and FIGS.

  First, as shown in FIG. 1, an optical waveguide substrate 21 on which an optical waveguide is formed is supplied onto the heating mounting stage 3. The optical waveguide substrate 21 is adsorbed under reduced pressure on the heating stage 3 and preheated to a temperature suitable for the bonding material. When AuSn solder is used as the bonding material, the preheating temperature is preferably about 250 ° C., which is slightly lower than the melting point.

  Next, as shown in FIG. 5, a bonding material 29 such as AuSn solder is supplied to the LD mounting position 23 of the optical waveguide substrate 21. The LD is adsorbed to the glass arm 17 under reduced pressure so that the lower surface of the protrusion of the glass arm 17 and the surface on the active layer side of the LD are in contact with the LD height reference surface.

  As shown in FIG. 6, the optical waveguide on the optical waveguide substrate 21 and the active layer electrode of the LD are image-measured by the CCD camera through the glass arm 17, and the LD mounting position is corrected by the XY axis stage 5 and the θz axis stage 8. .

  When the horizontal alignment is completed on the XY axis stage 5 and the θz axis stage 8, the Z axis stage 6 is driven to lower the mounting arm 4, and the lower surface of the LD is brought into contact with AuSn solder.

  FIG. 7 shows a state where the LD is in contact with the AuSn solder. At this time, the mounting arm 4 is not in contact with either the lower stopper or the upper stopper. A load obtained by adding the thrust of the voice coil motor 13 to the weight of the mounting arm 4 and the glass arm 17 acts on the LD. If the thrust of the voice coil motor is applied upward, the load applied to the LD can be reduced.

  In this state, the temperature of the heating mounting stage 3 is heated to a temperature (for example, 350 ° C.) higher than the melting point of the AuSn solder, and the AuSn solder is melted.

  FIG. 8 shows a state in which the glass arm 17 that has melted AuSn solder and adsorbed the LD is lowered. At this time, since the glass arm reference surface and the upper surface of the optical waveguide substrate 21 are in contact with each other, the optical axis height of the optical waveguide matches the optical axis height of the LD active layer without adjustment. The bonding material such as AuSn solder absorbs the variation in the distance between the LD lower surface and the optical waveguide substrate 21. When this state is reached, heating of the heating stage 3 is stopped, the temperature is lowered, and the solder is solidified.

  FIG. 9 shows a state in which the solder is solidified, the vacuum suction is released, and the glass arm 17 is retracted. After the solder is solidified, the vacuum suction of the glass arm 17 is released, the glass arm 17 is retracted from the LD, and the LD mounting onto the optical waveguide substrate 21 is completed.

In this manner, the lower surface of the LD is mounted on the optical waveguide substrate 21 with the bonding material at a height where the glass arm reference surface and the upper surface of the optical waveguide are in contact with each other. As described above, the glass arm reference surface and the upper surface of the optical waveguide are corrected after the horizontal position correction is performed by providing the glass arm with a projection surface having a height equal to the distance between the LD height reference surface and the glass arm reference surface. When the LD is mounted so as to be in contact with each other, the optical axis height of the optical waveguide can coincide with the optical axis height of the LD active layer. Therefore, the optical axis height of the optical waveguide and the optical axis height of the LD active layer can be matched without adjusting the height, so that productivity is high. Further, since the LD is bonded on the surface opposite to the active layer, the active layer is not subjected to residual stress due to solder bonding or the like, so that the characteristics of the LD do not deteriorate.
FIG. 10 is a flowchart showing the manufacturing procedure.

[Second Embodiment]
A second embodiment in which the present invention is preferably implemented will be described.

  In the second embodiment, one end of the optical waveguide upper surface 26 and the glass arm reference surface 28 are brought into contact with each other, the end of the opposite glass arm reference surface is floated, and the glass arm is placed on the optical waveguide substrate. Mount with a fixed amount of tilt. In the second embodiment, the glass arm 17 is tilted to adjust the optical axis so that the LD active layer on the optical waveguide side rises. Therefore, the height of the protrusion 27 of the glass arm 17 is set so that It is formed larger than the level difference from the LD height reference plane.

  FIG. 11 is a side view of the optical module according to the second embodiment viewed from the LD side in the optical axis direction.

  Since the optical axis height of the LD changes according to the tilt amount of the glass arm, the optical axis height of the optical waveguide of the optical waveguide substrate matches the optical axis height of the LD when the tilt amount of the glass arm is appropriately adjusted. .

In FIG. 11, the upper surface of the optical waveguide and the end of the glass arm reference surface are in contact with each other with the glass arm tilted in the θy axis direction with respect to the optical waveguide substrate.
The height from the glass arm reference plane to the LD active layer optical axis is b, the distance from the end of the glass arm tip (left end in FIG. 11) to the LD active layer optical axis is L1, and the glass arm reference plane is When the angle with respect to the upper surface of the optical waveguide is dθy, Δh = L1 x sin dθy + b x (1-cos dθy) is obtained by tilting the glass arm by dθy.
Therefore, the optical axis height can be moved upward, and the optical axis height can be adjusted.

  When the method of the present invention is used, the optical axis height of the LD can be set at a predetermined position by tilting the glass arm by an amount corresponding to the height error, and this occurs in the manufacture of the projection of the glass arm. The accuracy variation of 1 μm or less can be suppressed. Furthermore, even if an error occurs between the optical waveguide top surface and the optical axis height of the LD, or when the optical axis height is different for different types, it is possible to cope with it simply by adjusting the tilt amount of the θy axis stage. It becomes possible. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

[Third Embodiment]
A third embodiment in which the present invention is preferably implemented will be described.
In the third embodiment shown in FIG. 12, the optical axis height of the LD is adjusted by tilting the glass arm with respect to the optical waveguide substrate in the θx axis direction.

In this embodiment, the height from the glass arm reference surface to the active layer optical axis of the LD is b, and the distance from the end of the glass arm tip (left end in FIG. 12) to the end surface on the light emitting side of the LD is L2. When the angle between the glass arm reference surface and the optical waveguide upper surface is dθx, Δh = L 2 x sin dθx + b x (1−cos dθx) is obtained by tilting the glass arm by dθx.
Only the optical axis height can be moved upward. Since other configurations are the same as those in the first and second embodiments, description thereof is omitted.
[Fourth Embodiment]
A fourth embodiment in which the present invention is preferably implemented will be described.

  In the fourth embodiment shown in FIG. 13, the projection of the glass arm is changed to a projection shape that contacts the LD electrode surface instead of the LD height reference plane, and the height of the projection is changed between the upper surface of the optical waveguide, the LD electrode surface, and the like. The optical axis height of the LD is adjusted so that the upper surface of the optical waveguide and the end of the glass arm reference surface are in contact with each other with the glass arm tilted in the θy axis direction with respect to the optical waveguide substrate. doing.

  In this embodiment, by measuring the thickness of the LD electrode in advance, if the inclination amount of the glass arm is corrected by an amount corresponding to the thickness of the LD electrode, the optical axis height of the LD is set to a predetermined position. Can be set to For this reason, even if LDs having different LD electrode shapes are employed, they can be mounted with the same glass arm. Also, even if an error occurs between the optical waveguide top surface and the optical axis height of the LD, or when the optical axis height is different for different types, it is possible to cope with it simply by adjusting the tilt amount of the θy axis stage. It becomes possible. The direction in which the glass arm is tilted may be tilted in the optical axis direction (θy axis) or tilted in the direction perpendicular to the optical axis (θx axis). Since other configurations are the same as those in the first to third embodiments, description thereof is omitted.

  Each of the above embodiments is an example of a preferred embodiment of the present invention, and the present invention is not limited to these.

As an application example of the present invention, there is an optical module using DFB-LD or EML whose characteristics deteriorate when a residual stress is generated in the active layer of the LD. In addition, the same embodiments and effects can be obtained by using an end-face incident type PD (photodiode).

DESCRIPTION OF SYMBOLS 1 Optical module manufacturing apparatus 2 Image measurement processing apparatus 3 Heating mounting stage 4 Mounting arm 5 XY axis stage 6 Z axis stage 7 Image recognition optical system 8 θz axis stage 9 Parallel leaf spring 10 Z axis fine movement unit 11 Upper stopper 12 Lower stopper 13 Voice coil motor 14 Displacement sensor 15 θy axis stage 16 θx axis stage 17 Glass arm 18 Adsorption hole 19 LD
DESCRIPTION OF SYMBOLS 20 Optical module 21 Optical waveguide board | substrate 22 Optical waveguide 23 LD mounting area | region 24 LD height reference plane 25 Optical axis 26 Optical waveguide upper surface 27 Protrusion 28 Glass arm reference plane 29 Joining material 30 Active layer electrode 31 Wiring electrode 32 Active layer

Claims (4)

An optical module manufacturing apparatus for mounting an optical element on a substrate,
A mounting stage for holding the surface on which the optical waveguide of the substrate is formed in a state in which the surface is directed vertically upward;
A mounting arm for holding the surface of the optical element on the active layer side in a vertically upward direction;
An XY axis stage for transferring the mounting arm to an arbitrary position in the horizontal direction;
A Z-axis stage for transferring the mounting arm to an arbitrary position in the vertical direction;
An image measurement processing device that photographs the mounting area of the optical element on the substrate and measures the mounting area, and
The mounting arm has a glass arm with a protrusion, holds the optical element on the glass arm through the protrusion, and the height of the protrusion is a surface on which the distance between the active layer and the active layer can be accurately formed. A first height equal to a step between the height reference plane of the optical element and the upper surface of the optical waveguide of the substrate, or the height reference plane or the electrode plane of the optical element and the substrate A second height greater than the step between the upper surface of the optical waveguide,
Horizontal alignment of the optical axis is performed by bringing the end face of the optical waveguide formed on the substrate close to the active layer of the optical element,
When the protrusion is at the first height, the optical element is mounted on the substrate at a position where the upper surface of the optical waveguide of the substrate and the lower surface of the glass arm are in contact with each other, thereby forming the optical waveguide and the active layer. The optical axis height matches,
When the protrusion is at the second height, the optical element is mounted on the substrate with the glass arm inclined with respect to the substrate, so that the optical axis height of the optical waveguide and the active layer is Match,
An optical module manufacturing apparatus. The projection of the glass arm is located outside the electrode and wiring formed in the active layer of the optical element , and is disposed at a location facing the surface corresponding to the height reference plane of the optical element. The optical module manufacturing apparatus according to claim 1. An optical module manufacturing method for mounting an optical element on a substrate,
The substrate is held in a mounting stage surface optical waveguide is formed of the substrate being directed upward in the vertical direction,
Holding the optical element mounting arm surface of the active layer side of the optical element through the glass arm with protrusions in a state directed vertically upward,
The height of the protrusion is a first step equal to the level difference between the height reference plane of the optical element, which is a plane on which the distance in the height direction from the active layer can be accurately formed, and the upper surface of the optical waveguide of the substrate. Or a second height greater than the step between the height reference plane or the electrode surface of the optical element and the upper surface of the optical waveguide of the substrate,
Move the mounting arm horizontally and vertically to bring the optical element close to the substrate,
The end face of the optical waveguide substrate and is close to the optical element have rows optical axis alignment in the horizontal direction,
When the protrusion is at the first height, the optical element is mounted on the substrate at a position where the upper surface of the optical waveguide of the substrate and the lower surface of the glass arm are in contact with each other, thereby forming the optical waveguide and the active layer. Match the optical axis height,
When the protrusion is at the second height, the optical element is mounted on the substrate in a state where the glass arm is inclined with respect to the substrate, so that the optical axis height of the optical waveguide and the active layer is increased. Match,
A method for manufacturing an optical module. The glass arm, an optical module manufacturing method according to claim 3, wherein the projection on the electrode and the wiring formed on the optical element is characterized in that the suction holding in contact.

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