JP3986196B2 - Manufacturing method of optical semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical semiconductor device manufacturing technique, particularly a pellet bonding technique. For example, in an optical semiconductor device manufacturing process, a laser diode pellet (hereinafter referred to as LD) and a photodiode pellet (hereinafter referred to as PD) are sub-subjected. The present invention relates to an effective technique that can be used for straight bonding.
[0002]
[Prior art]
In the manufacturing process of an optical semiconductor device, when LD and PD are bonded to a substrate, an alignment mark (hereinafter referred to as a substrate mark) formed on the upper surface of the substrate and a lower surface of the LD and PD are formed. It is necessary to align and bond the alignment marks (hereinafter referred to as LD and PD marks). That is, in this pellet bonding operation, it is necessary to recognize the LD and PD marks and align them with the substrate marks. However, since the LD and PD marks are formed on the lower surface of the LD and PD, they cannot be recognized from above the LD and PD. Since the mark on the substrate is covered with the LD and PD, it cannot be recognized from above the LD and PD.
[0003]
An example in which an optical semiconductor device is described is JP-A-8-166523.
[0004]
[Problems to be solved by the invention]
Therefore, a method is adopted in which the LD and PD are photographed from above with an infrared transmission illumination device and an infrared camera, and the LD and PD marks and substrate marks are simultaneously recognized and aligned and bonded. It is possible to do.
[0005]
However, the present inventor has revealed that the bonding method for automatically bonding LD and PD to a substrate using an infrared transmission illumination device and an infrared camera has the following problems.
[0006]
When recognizing LD and PD marks and substrate marks at the same time using an infrared transmission illumination device and an infrared camera, the focus of the infrared camera is simultaneously focused on both the LD and PD marks and the substrate mark. Therefore, it is necessary to arrange the LD and PD marks and the substrate marks at the same height. However, if alignment is performed while the LD and PD marks and the substrate mark are in contact with each other, the alignment surface between the LD and PD and the substrate will be damaged. It is necessary to leave a gap.
[0007]
However, since the substrate, LD, and PD have a thickness variation of about ± 15 μm, the infrared camera is focused only by setting a certain gap in advance because of the variation in the thickness of the substrate, LD, and PD. A situation occurs in which the substrate contacts the LD and the PD.
[0008]
Therefore, with the focus of the infrared camera focused on the substrate mark, the LD and PD placed at a safe height are photographed with the infrared camera, and the LD and PD are gradually brought closer to the substrate while watching the monitor image. Adopting a bonding method when the LD and PD marks and the substrate mark are visible on the same screen is conceivable.
[0009]
However, according to this method, the present inventors have revealed that there are the following problems. First, the bonding time becomes longer. Secondly, there may be a case where the LD and PD collide with the substrate too close. Third, since the distance between the substrate and the LD and PD is large, the stroke of the vertical movement during bonding becomes large, the mechanical error of the moving mechanism for moving the LD and PD increases, and the position before bonding As a result, the positional deviation after bonding becomes large and bonding cannot be performed with high accuracy.
[0010]
An object of the present invention is to provide a pellet bonding technique capable of appropriately bonding objects to be bonded having alignment marks facing each other.
[0011]
The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.
[0012]
[Means for Solving the Problems]
An outline of typical inventions among inventions disclosed in the present application will be described as follows.
[0013]
That is, the distance between a pair of objects to be bonded having alignment marks facing each other is measured, and the distance between the objects to be bonded is controlled by the measurement result when the alignment marks are aligned by recognition by an infrared camera. Features.
[0014]
According to the above-described means, even if there are variations in the thickness of the objects to be bonded, the objects to be bonded collide during alignment by controlling the distance between the objects to be bonded. Can be prevented. As a result, the objects to be bonded can be appropriately bonded regardless of variations in the thickness of the objects to be bonded.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view showing a pellet bonding apparatus according to an embodiment of the present invention. FIG. 2 is a process diagram showing a pellet bonding method of the method for manufacturing an optical semiconductor device according to one embodiment of the present invention. 3 to 5 are explanatory diagrams for explaining the operation.
[0016]
In this embodiment, the pellet bonding apparatus is configured to be used in a pellet bonding step in the manufacturing method for manufacturing the optical module with fiber shown in FIG.
[0017]
As shown in FIG. 3, an optical module M with a fiber as an optical semiconductor device includes a substrate 1 formed from a silicon (Si) substrate into a rectangular flat plate shape, an LD 2 and a PD 3, and a substrate 1. An optical fiber 4 fixed to the holding groove and coupled to the LD 2, a plurality of inner leads 7 electrically connected to the LD 2 and the PD 3 via the electrical wiring 5 and the wires 6, and a connection to each inner lead 7. The outer lead 8 and a resin sealing body 9 in which a portion excluding the outer lead 8 is sealed with a resin are provided.
[0018]
A substrate mark (hereinafter referred to as a first mark) 1a is formed on the upper surface of the substrate 1 as shown in FIG. An LD mark (hereinafter referred to as second mark) 2a is formed on the lower surface of LD2 as shown in FIG. 4B, and a PD mark (hereinafter referred to as third mark) is formed on the lower surface of PD3. 3a is formed as shown in FIG. 4 (c). Then, in the pellet bonding step, LD2 and PD3 are aligned on the substrate 1, and the first mark 1a, the second mark 2a and the third mark 3a are aligned and bonded as shown in FIG. Is done.
[0019]
As shown in FIG. 1, a substrate supply / finished product storage stage (hereinafter referred to as “first”) that supplies a substrate 1 to the pellet bonding apparatus and stores a bonded substrate (hereinafter referred to as “finished product”) 1A. 10), an LD / PD supply stage (hereinafter referred to as a second stage) 20 for supplying LD2 and PD3, and a bonding stage (hereinafter referred to as a third stage) 30 for performing bonding. Is provided.
[0020]
The first stage 10 is provided with a first XY robot 12 for moving the first tray 11 in the XY directions. The first tray 11 stores the substrate 1 to be bonded from now on and is bonded. The finished product 1A is stored. A first position recognition device 13 is installed directly above the first XY robot 12, and the first position recognition device 13 is configured to recognize the positions of the substrate 1 and the finished product 1A.
[0021]
The second stage 20 is provided with a second XY robot 22 for moving the second tray 21 in the X and Y directions. The second tray 21 accommodates LD2 and PD3 to be bonded from now on. A second position recognition device 23 is installed directly above the second XY robot 22, and the second position recognition device 23 is configured to recognize the positions of LD2 and PD3.
[0022]
The third stage 30 is provided with a Θ table 31 and an XY table 32, and the Θ table 31 and the XY table 32 can be moved in the Θ direction and the XY direction while holding the substrate 1. An infrared camera 33 with an infrared transmissive illumination device 34 is installed directly above the XY table 32, and the infrared camera 33 is configured to photograph a subject illuminated by the infrared transmissive illumination device 34.
[0023]
A first measurement stage 14 for measuring the thickness of the substrate 1 is set at an intermediate position between the first stage 10 and the third stage 30, and the first measurement stage 14 has a first laser displacement meter 41. Are equipped. A second measurement stage 24 for measuring the thicknesses of the LD 2 and the PD 3 is set at an intermediate position between the second stage 20 and the third stage 30. The second measurement stage 24 has a second laser displacement meter 42. Are equipped.
[0024]
On one side (hereinafter referred to as rear side) between the first stage 10 and the third stage 30, the first X robot 15 extends in the left-right direction (hereinafter referred to as X hereinafter) across the first stage 10 and the third stage 30. The first X robot 15 is configured to move the substrate Z robot 16 and the finished product Z robot 17 in the X direction, respectively. The substrate Z robot 16 moves a substrate collet (hereinafter referred to as a first collet) 18 and a finished product collet (hereinafter referred to as a second collet) 19 as first holding means in a vertical direction (hereinafter referred to as Z). It is configured to move (up and down) in the direction. The first collet 18 is configured to hold the substrate 1 by vacuum suction, and the second collet 19 is configured to hold the finished product 1A by vacuum suction.
[0025]
A second X robot 25 is laid in the X direction across the first stage 10 and the third stage 30 behind the second stage 20 and the third stage 30, and the second X robot 25 is The robot 26 is configured to move in the X direction. The Y robot 26 is configured to move the LD / PD Z robot 27 in the front-rear direction (hereinafter referred to as the Y direction). The LD / PD Z robot 27 moves the Θ robot 28 in the Z direction ( It is configured to move up and down. The Θ robot 28 is configured to rotate an LD / PD collet (hereinafter referred to as a third collet) 29 as second holding means in the Θ direction within a horizontal plane. The third collet 29 is configured to hold the LD2 and PD3 by vacuum suction and to transmit infrared rays.
[0026]
Next, a pellet bonding method of an optical module manufacturing method according to an embodiment of the present invention will be described with reference to FIG.
[0027]
The substrate 1 as the first object to be bonded is moved in the XY direction by the first XY robot 12, and the outer shape and position are recognized by the first position recognition device 13. When recognized, the substrate 1 is held by vacuum suction by the first collet 18. The first collet 18 holding the substrate 1 is lifted by the substrate Z robot 16 and then transferred to the first measurement stage 14 by the first X robot 15. In FIG. 2, SS is a substrate.
[0028]
In the first measurement stage 14, the thickness t of the substrate 1 ₁ Is measured as shown in FIG. That is, the first laser displacement meter 41 provided on the first measurement stage 14 irradiates the distance measuring laser to the substrate 1 and the first collet 18, and the distance to the substrate 1 and the distance to the first collet 18. The thickness t of the substrate 1 due to the difference between ₁ Is measured. Measured thickness 1 of substrate 1 ₁ Is transmitted to a controller that controls the LD / PD Z robot 27 for performing bonding.
[0029]
Thickness t ₁ The substrate 1 having been measured is conveyed to the third stage 30 and transferred onto the XY table 32 while being vacuum-sucked and held by the first collet 18.
[0030]
On the other hand, the LD 2 as the second object to be bonded is moved in the XY direction by the second XY robot 22, and when the outer shape and position are recognized by the second position recognition device 23, the LD 2 is vacuum-held by the third collet 29. The The third collet 29 holding the LD 2 is lifted by the LD / PD Z robot 27, and then transferred to the second measurement stage 24 by the second X robot 25.
[0031]
In the second measurement stage 24, the thickness t of the LD2 ₂ Is measured as shown in FIG. That is, the laser for distance measurement is irradiated to the LD 2 and the third collet 29 by the second laser displacement meter 42 provided on the second measurement stage 24, and the difference between the distance to the LD 2 and the distance to the third collet 29. By the thickness t of LD2 ₂ Is measured. Measured thickness t2 of LD2 ₂ Is transmitted to a controller that controls the LD / PD Z robot 27 for performing bonding.
[0032]
The LD 2 whose thickness has been measured is vacuum-sucked and held by the third collet 29, and is transferred to the third stage 30 and aligned with the substrate 1 held on the XY table 32 by the following method for bonding. Is done.
[0033]
First, the substrate 1 held on the third stage 30 is illuminated by the infrared transmission illumination device 34, and the focal point f of the infrared camera 33 is focused on the upper surface of the substrate 1, as shown in FIG. The first mark 1a is recognized by the infrared camera 33. Then, when the substrate 1 is operated by the Θ table 31 and the XY table 32 of the third stage 30, the recognized first mark 1 a is aligned with the reference position of the infrared camera 33.
[0034]
The LD 2 conveyed to the third stage 30 is illuminated by the infrared rays of the infrared transmissive illumination device 34 that passes through the third collet 29. Subsequently, when the third collet 29 is lowered by the LD / PD Z robot 27, the distance L between the substrate 1 and the LD 2 is reduced as shown in FIG. It is set to 10 μm which is less than the focal depth fd. At this time, the thickness t of the substrate 1 measured in the first measurement stage 14 ₁ And the thickness t of the LD 2 measured in the second measurement stage 24 ₂ The movement distance of the LD / PD Z robot 27 is corrected. This thickness t ₁ And t ₂ By using the correction, the distance L between the substrate 1 and the LD 2 can be precisely and automatically adjusted to a very small value of 10 μm.
[0035]
Then, when the third collet 29 is operated by the second X robot 25, the Y robot 26, and the Θ robot 28, the recognized second mark 2a is aligned with the reference position of the infrared camera 33.
[0036]
With the distance L between the substrate 1 and LD2 adjusted to 10 μm, which is a value less than the focal depth fd of the infrared camera 33, the infrared rays of the infrared transmission illumination device 34 are transmitted through the third collet 29 and LD2 and illuminated. Since the focal point f of the infrared camera 33 is focused on the upper surface of the substrate 1, the first mark 1a and the second mark 2a are simultaneously clearly recognized as shown in FIG. It becomes a state. By relatively operating the substrate 1 and the LD 2 in this clear recognition state, the first mark 1a and the second mark 2a can be precisely detected while avoiding the LD 2 from contacting the substrate 1. Aligned.
[0037]
When the first mark 1a and the second mark 2a are precisely aligned, as shown in FIG. 5 (d), the LD / PD Z robot 27 is only set to a very short distance of 10 μm. The LD 2 is bonded to the substrate 1 by being lowered. At this time, since the distance between the substrate 1 and the LD 2 is extremely small, the mechanical error of the LD / PD Z robot 27 is suppressed to be small, so that the LD 2 can be precisely bonded to the substrate 1. .
[0038]
When the bonding operation is completed, the third collet 29 releases the holding of the LD 2 and is raised by the LD / PD Z robot 27, and then returned to the second stage 20 by the second X robot 25.
[0039]
While the LD 2 is bonded to the substrate 1, the PD 3 as the third object to be bonded is moved in the XY direction by the second XY robot 22, and the outer shape and position are recognized by the second position recognition device 23. The recognized PD 3 is vacuum-sucked and held by the third collet 29 that has returned from the third stage 30 to the second stage 20. The third collet 29 holding the PD 3 is lifted by the LD / PD Z robot 27 and then transferred to the second measurement stage 24 by the second X robot 25.
[0040]
In the second measurement stage 24, the thickness of PD3 is measured in the same manner as in the case of LD2. The PD 3 whose thickness has been measured is conveyed to the third stage 30 while being vacuum-sucked and held by the third collet 29, and is the same method as described above for the LD 2 on the substrate 1 to which the LD 2 has been previously bonded. Are aligned and bonded.
[0041]
When the bonding operation is completed, the third collet 29 releases the holding of the PD 3 and is lifted by the LD / PD Z robot 27 and then returned to the second stage 20 by the second X robot 25.
[0042]
The finished product 1A in which the LD2 and the PD3 are bonded to the substrate 1 is vacuum-sucked and held by the second collet 19, lifted by the substrate Z robot 16, and then moved from the third stage 30 by the first X robot 15. It is conveyed to one stage 10. In the first stage 10, the position where the finished product 1 </ b> A of the first tray 11 should be stored is recognized by the first position recognition device 13. The finished product 1 </ b> A conveyed from the third stage 30 to the first stage 10 is stored by releasing the holding of the second collet 19 at the recognized storage position of the first tray 11.
[0043]
Thereafter, by repeating the above operation, the bonding work of the LD 2 and PD 3 to the substrate 1 is sequentially performed.
[0044]
According to the embodiment, the following effects can be obtained.
[0045]
1) Measure the thickness of the substrate and LD and PD in advance, and use the measurement results to avoid the collision between the substrate and LD and PD, and set the distance between the substrate and LD and PD to infrared. By narrowing down to the focal depth of the camera, the first mark, the second mark, and the third mark can be simultaneously and clearly recognized by the infrared camera when the LD and PD are bonded to the substrate. And the second mark and the third mark can be precisely aligned, and the LD and PD can be precisely and automatically bonded to the substrate.
[0046]
2) According to 1), since the LD and PD can be accurately and automatically bonded to the substrate regardless of variations in the thickness of the substrate, LD and PD, the thickness of the substrate, LD and PD The strictness of dimensions can be relaxed, and as a result, the productivity of the entire optical module can be increased.
[0047]
3) According to the above 1), the collision between the substrate and the LD and PD can be prevented, so that the yield of pellet bonding can be improved.
[0048]
4) By using the infrared camera to transmit LD and PD and simultaneously recognize and align the first mark and the second mark, it is possible to rationalize the bonding work between the substrate and LD and PD with a single optical system. Therefore, the productivity of the entire optical module can be increased.
[0049]
5) By automating the bonding work between the substrate and the LD and PD, it is possible to realize labor saving, shortening of working time, equalizing quality and improving reliability.
[0050]
FIG. 6 is a front view showing main parts of a pellet bonding apparatus according to Embodiment 2 of the present invention.
[0051]
This embodiment is different from the above embodiment in that, instead of measuring the thickness of the substrate, LD, and PD, the distance between the substrate, LD, and PD is measured by a strip laser displacement meter.
[0052]
That is, as shown in FIG. 6, when the LD 2 is bonded to the substrate 1 held by the third stage 30 by the third collet 29, the distance L between the substrate 1 and the LD 2 is the band-shaped laser displacement. The third collet 29 is lowered while being measured by the total 43, and the interval L is reduced to a value (for example, 10 μm) corresponding to the focal depth of the infrared camera 33.
[0053]
According to this embodiment, since it is not necessary to measure the thickness of the substrate, LD, and PD in the middle of conveyance, the bonding time can be shortened. In addition, by directly measuring the distance between the substrate and the LD and PD, it is possible to avoid the effects of changes in the height of the third stage due to heat, etc., so that the alignment accuracy and bonding accuracy are further improved. Can do.
[0054]
FIG. 7 is a front view showing the main part of the bonding apparatus according to the third embodiment of the present invention.
[0055]
This embodiment is different from the above embodiment in that, instead of measuring the thickness of the substrate, LD, and PD, the distance between the substrate, LD, and PD is measured by a reflective laser displacement meter. .
[0056]
That is, as shown in FIG. 7, when the LD 2 is bonded to the substrate 1 held by the third stage 30 by the third collet 29, the distance L between the substrate 1 and the LD 2 is a reflection type laser. The third collet 29 is lowered while being measured by the displacement meter 44, and the interval L is reduced to a value (for example, 10 μm) corresponding to the focal depth of the infrared camera 33.
[0057]
According to this embodiment, since it is not necessary to measure the thickness of the substrate, LD, and PD in the middle of conveyance, the bonding time can be shortened. In addition, by directly measuring the distance between the substrate and the LD and PD, it is possible to avoid the effects of changes in the height of the third stage due to heat, etc., so that the alignment accuracy and bonding accuracy are further improved. Can do.
[0058]
Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Nor.
[0059]
For example, the first stage, the second stage, the third stage, each transport device, the collet, and the like are not limited to the configuration of the above embodiment, and other configurations may be used.
[0060]
In the above description, the case where the invention made mainly by the present inventor is applied to the pellet bonding technique of the optical module manufacturing method, which is the field of use behind it, has been described, but the present invention is not limited to this. The present invention can be applied to the whole pellet bonding technique of the method for manufacturing an optical semiconductor device.
[0061]
【The invention's effect】
The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
[0062]
The object to be bonded is measured during alignment by measuring the distance between objects to be bonded having alignment marks facing each other and feeding back the measurement result when aligning the objects to be bonded to control the distance between the alignment marks. Since collision between the objects can be prevented, the objects to be bonded can be appropriately bonded regardless of an error in the thickness of the objects to be bonded.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a pellet bonding apparatus according to an embodiment of the present invention.
FIG. 2 is a process diagram showing a pellet bonding method of an optical semiconductor device manufacturing method according to an embodiment of the present invention.
FIGS. 3A and 3B show an optical module, in which FIG. 3A is a plan sectional view, FIG. 3B is a front sectional view, and FIG. 3C is a side sectional view taken along line cc of FIG.
4A is a plan view showing a substrate, FIG. 4B is a bottom view showing the LD, FIG. 4C is a bottom view showing the PD, and FIG. 4D is a plan view of the LD showing the positional relationship of the marks. is there.
FIG. 5 is an explanatory view for explaining a pellet bonding method.
FIG. 6 is a front view showing main parts of a pellet bonding apparatus according to Embodiment 2 of the present invention.
FIG. 7 is a front view showing main parts of a pellet bonding apparatus according to Embodiment 3 of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Substrate (first object to be bonded), 1a ... First mark (substrate alignment mark), 1A ... Finished product (bonded product of substrate and LD and PD), 2 ... LD (second object to be bonded) ), 2a, second mark (LD alignment mark), 3 PD (third bonded object), 3a, third mark (PD alignment mark), 4 optical fiber, 5 electrical wiring, 6 wire , 7 ... Inner lead, 8 ... Outer lead, 9 ... Resin encapsulant, 10 ... First stage (substrate supply combined finished product storage stage), 11 ... First tray, 12 ... First XY robot, 13 ... First Position recognition device, 14 ... first measurement stage, 15 ... first X robot, 16 ... Z robot for substrate, 17 ... Z robot for finished product, 18 ... first robot (Collet for substrate, first holding means), 19 ... second collet (collet for finished product), 20 ... second stage (LD / PD supply stage), 21 ... second tray, 22 ... second XY Robot, 23 ... second position recognition device, 24 ... second measurement stage, 25 ... second X robot, 26 ... Y robot, 27 ... Z robot for LD / PD, 28 ... Θ robot, 29 ... third collet (LD -Collet for PD, second holding means), 30 ... third stage (bonding stage), 31 ... Θ table, 32 ... XY table, 33 ... infrared camera, 34 ... infrared transmission illumination device, 41 ... first laser displacement meter 42 ... second laser displacement meter, 43 ... band laser displacement meter, 44 ... reflection laser displacement meter.

Claims (1)

After measuring the thickness of each of the pair of objects to be bonded having alignment marks facing each other and recognizing one position of the pair of objects to be bonded by an infrared camera, the other position of the pair of objects to be bonded is determined. An optical semiconductor device manufacturing method for performing alignment between the alignment marks recognized by the infrared camera,
The distance between the pair of objects to be bonded at the time of alignment is within the range where the pair of objects to be bonded do not contact each other depending on the thickness of the object to be bonded and the position of the object to be bonded. is controlled to below the depth of focus of the infrared camera, the thickness of the bonding material is a method of manufacturing an optical semiconductor device according to claim Rukoto measured by the reflection type laser displacement meter.

Images