JP2002111113A - Optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive optical module by reducing the occurrence of optical coupling defects by suppressing the change of an optical element in position, height, and levelness when solder is melted at the time of mounting the optical element by passive alignment. SOLUTION: Either or both of a substrate and the optical element has a solder film formed on metallized part of an electrode and a connecting structure which fixes the optical element and substrate by temporarily connecting the element and substrate to each other through a bump for temporary connection separately from the solder film. The connecting structure connects the substrate to the optical element by melting the solder of the solder film by heating the film to a temperature higher than the melting point of the solder. Since the bump is temporarily connected to metallized part of an optical element, the position, height, and levelness of the optical element do not change at the time of melting the solder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to the mounting of optical elements and optical components on an optical module and an optical circuit board.

[0002]

2. Description of the Related Art An optical module is mounted in a state where an optical waveguide or an optical fiber and an optical element are optically coupled, and an optical signal emitted from the optical element is transmitted to the outside through the optical waveguide or the optical fiber. The device is capable of receiving an optical signal from the outside or an optical element. Transmission of an optical signal is performed by energizing a laser diode (hereinafter, LD) to emit light, and reception is performed by receiving the optical signal by a photodiode (hereinafter, PD) and extracting it as a photocurrent. A lens may be inserted between the optical waveguide or the optical fiber and the optical element to increase the efficiency of optical coupling, or a filter or an optical isolator may be inserted to remove excess light. Such a mounting structure differs depending on the target optical communication route.For example, in a mainline optical communication module connecting between large cities, optical components such as lenses and optical isolators are mounted together with optical elements and optical fibers. In a subscriber optical module, a lens or the like may not be used for cost reduction.

When mounting an optical element, an optical element is fixed on a substrate having an optical waveguide by soldering, or an optical fiber is fixed on the substrate after the optical element is fixed on the substrate by soldering. At this time, in order to obtain optical coupling between the optical waveguide or the optical fiber and the optical element, the position, height, levelness, and the like of the optical element are important. In particular, it is essential to assemble an optical module at low cost in subscriber optical communication. When light is directly coupled to an optical element and a waveguide without a lens, a positional accuracy of about ± 1 mm is required.

Conventionally, in a subscriber optical module, a waveguide is formed on a Si substrate, an electrode metallization is formed on an optical element mounting portion at an end of the waveguide, and a thin film having a thickness of several mm is formed thereon.
A substrate on which Au-Sn solder is formed by vapor deposition is used. Then, the optical element and the index formed on the substrate are aligned in advance, and the optical element is pressed and temporarily fixed on the vapor-deposited solder film.After temporarily fixing a plurality of optical elements, the substrate is heated to a temperature equal to or higher than the melting point of the solder. Then, a plurality of optical elements were connected at once. In this manner, the connection of the elements by the index alignment is referred to as passive alignment mounting.

On the other hand, self-alignment mounting attempts to control the position, height, and levelness of an optical element by the surface tension of the molten solder. However, in self-alignment mounting, mounting accuracy depends on the atmosphere. This is because when oxygen is present in the atmosphere, the surface of the molten solder is oxidized and the original surface tension of the molten solder is not generated. Usually, a flux is used to prevent oxidation, but if the surface of the optical element is contaminated with the flux, optical coupling may not be obtained. Therefore, the flux is not used in the connection of the optical element. Therefore, a technique has been reported in which a special reducing atmosphere (such as formic acid) is used or a mixed atmosphere of hydrogen and nitrogen is used to prevent the oxidation of the solder surface. However, when performing such an atmosphere replacement, strict exhaust equipment is required,
Further, as an essential problem, there remains such a problem that the height of the element depends on the amount of supplied solder.

In passive alignment mounting, optical elements must be positioned with higher precision than in self-alignment mounting. However, in the future, not only the subscriber optical communication module, but also the trunk line module, it is expected that the number of components will be reduced due to cost reduction, and the optical fiber and the optical element are optically coupled without a lens, or inexpensive. It becomes necessary to optically couple through a lens. In such a case, very high precision is required for the position, height, and horizontality of the optical element. In addition, it is expected that wavelength division multiplexing communication and the like will be widely used in trunk line modules, and the number of optical components in the optical module may increase as compared with a normal optical transmission module. In order to perform wavelength division multiplexing communication, in addition to a mechanism for transmitting light in a fiber, a mechanism for controlling the wavelength of light is required, and many optical components are mounted in the optical module. It is thought that it is done. Also in such a case, if the positional accuracy of the optical components is poor, the optical coupling will be poor.

Therefore, in mounting optical elements and optical components, accuracy such as position, height, and levelness is extremely important, and a technology for mounting the optical elements and optical components with higher accuracy and yield will be required in the future. .

[0008]

However, in the passive alignment mounting technique, the optical element or optical component is temporarily connected to the solder film on the substrate and then the solder is melted. It is feared that the yield will decrease.

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and has been developed for passive alignment mounting.
An object of the present invention is to provide an optical module in which the mounting accuracy of an optical element or an optical component is improved.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is configured as described in the appended claims. Thus, even when soldering, the positional accuracy such as the height can be ensured by the bump, so that an optical module with improved mounting accuracy can be provided.

[0011]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG.

FIG. 1 shows a substrate 1 on which an optical waveguide composed of a cladding layer 2 and a core layer 3 is formed, for mounting an LD element 20, a PD element 21, and an mPD element 22 at the end of the waveguide. There is an optical element mounting part, and the mounting part of each optical element has an Au-Sn solder film 12 for making electrical and mechanical connection, a wiring 5 and a wire bonding pad 6 connected thereto, and other optical element mounting parts. FIG. 1 shows an optical module substrate on which an index 4 for aligning a substrate and a bump 9 for temporary connection are formed, and optical elements. As shown in FIG. 4, an electrode metallization 7 or a temporary connection bump metallization 8 is formed under the solder film 12 or the temporary connection bump 9. In particular, the solder film 12 is formed so as to protrude outside the metallized electrode 7.

Usually, such an optical module substrate is made of Si
An optical waveguide is formed on a wafer or the like, and thereafter, an electrode metallization is formed, and a solder film is deposited. The temporary connection bump 9 of the present embodiment is made of Au, and is formed by depositing by sputtering, vapor deposition, or the like in the electrode forming process before solder vapor deposition, or after the solder vapor deposition, an Au ball is formed on the temporary connection bump metallization 8. It can also be formed by pressing.
The height of the temporary connection bump 9 is higher than the solder film 12,
In order to improve the mounting accuracy, the bumps 9 are flattened before mounting the optical element. At this time, the height of the bump 9 is adjusted so that the optical element and the waveguide are finally optically coupled in consideration of a change in the bump height when the optical element is temporarily connected in a later process.

FIG. 2 shows the solder connection side of the optical element.
7, metallization 24 for temporary connection, electrode 26 for solder connection,
And a metallization 28 for solder connection.
In the LD element 20, an index 27, a temporary connection metallization 24, and a solder connection electrode 25 are formed. In this embodiment, all of these metallized surfaces are Au
It is. Note that the metallized position on the solder connection surface side of the mPD element 22 is the same as that of the PD element 21 and is not shown. In the PD element and the mPD element, the electrode metallized area is preferably as small as the electrode 26 in order to reduce the electric capacity of the electrode portion and improve the high frequency characteristics. On the other hand, in the LD element, in order to radiate heat generated from the active layer due to light emission to the substrate, it is necessary to completely fill the lower part of the active layer with solder and connect it to the substrate. Therefore, the electrode 25 of the LD element is formed so as to completely cover the active layer.

Each optical element is pressed against the temporary connection bump 9 so that the index 4 of the substrate 1 and the index 27 of the optical element match. At this time, the height of each optical element is determined by the height of the temporary connection bump 9, and the temporary connection metallization 24 of each optical element and the temporary connection bump 9 adhere to each other, and each optical element is fixed. . This state is shown in FIGS.
It is. FIG. 4 shows a connection structure taken along the line AA ′ of FIG. The strength of the temporary connection is determined by the adhesion between the temporary connection bump 9 and the temporary connection metallization 24 of the optical element. By setting the bump 9 to be soft Au, when the optical element is pressed, Au plastically deforms. As a result, the connection area increases, and a connection strength of several grams to several tens of grams can be obtained. In order to obtain a higher temporary connection strength, the optical element is temporarily connected to the temporary connection bump 9.
When pressed against the solder film 12, heating may be performed at a temperature equal to or lower than the melting point (278 ° C.) of the solder film 12, or ultrasonic waves may be used together.

When the temporary connection of all the optical elements is completed, the entire substrate 1 is heated to melt the solder film 12 as shown in FIG. The atmosphere at this time does not need to be reducing, and a nitrogen atmosphere is sufficient. However, the oxygen concentration in a nitrogen atmosphere is
It is desirable that the content be 1000 ppm or less. The solder film 12
Since the solder is formed so as to protrude outside the electrode metallization 7, the solder melted outside the electrode metallization 7 is repelled by the surface of the substrate 1 and collects on the electrode metallization 7. As a result, the height of the molten solder 13 increases,
It contacts the electrode metallization 26 of the PD element or the electrode metallization 25 under the active layer of the LD element. Molten solder 13
Is spread on the metallizations 25 and 26 on the optical element side, the surface tension of the molten solder acts on the optical element. However, since each optical element is fixed by the bump 9, the position, height, levelness, and the like change. There is nothing. Therefore, by cooling in this state, the substrate side electrode metallization 7 and the optical element side electrode metallizations 25 and 26 are connected without changing the height of the optical element, and each optical element is fixed on the substrate 1 by soldering. Is done.

In the prior art in which no bump for temporary connection is used as in this embodiment, most of the lower surface of the optical element is fixed by soldering. The connection strength at this time was several hundred grams or more by shearing. However, in actuality, when the metallization 23 on the upper surface of the optical element is connected by wire bonding in a later step, it is sufficient that the connection strength is such that the optical element does not come off, and there is no problem if the connection strength is about 50 grams. Therefore, in this embodiment, only the portion under the active layer is fixed by soldering in the LD element 20, but even in this state, the connection strength of 50 g or more is obtained, and the element does not shift due to wire bonding. Further, there is no problem with the heat radiation when the LD emits light, since the lower portion of the active layer is connected to the substrate 1 by solder. However, the temporary connection bump 9 also has the effect of assisting the heat radiation to the substrate side. PD element 21 and mPD
In the case of the element 23, since the strength is insufficient only with the optical element electrode portion 26, the metallization 2 for solder connection is provided behind the optical element.
8 are provided. The metallization layer 7 for connection is also provided under the solder film 12 behind the PD and mPD elements, similarly to FIG.
Are formed, and the solder protrudes outside the metallization. Therefore, as shown in FIG. 5, when the solder collects on the metallization 7, this portion is also fixed by the solder, and the connection strength of 50 g or more can be obtained in the case of the PD and mPD elements.

Regarding the electrical connection state, the pads 6 and 23 are externally connected to each other by wire bonding, and a current flows through the wiring 5, the substrate-side electrode metallization 7, the solder 13, and the optical element-side electrode metallization 25 or 26. The temporary connection bump 9 and the rear metallization 28 of the PD element do not participate in the electrical connection in this embodiment.
However, the connection portion of the metallization 28 behind the PD element may be formed with wiring on a substrate and electrically connected in some cases.

In this embodiment, the connection bumps are formed on the substrate side, because the substrate has a higher strength than the optical element and is less likely to be broken when the bumps are formed (even when the bumps are pressed). . The optical element has a light emitting active layer with p
Since a crystal for the n-junction is formed, for example, if an Au ball is pressed with a large force to form a large bump, the element may be broken.

However, if the bumps are formed with a force that does not destroy the optical element, the bumps can be formed in the state of the wafer before dicing. Considering that the bumps can be formed on the optical element side, the overall production efficiency is reduced. Can be improved.

It is important that the material of the connection bumps has a high strength of the temporary connection when the optical element is pressed. It is important that the bumps are soft and easily deformed. In the temporary connection, since the anchor effect due to the deformation of the bump (the strength is generated by engagement of the surface irregularities) is important, soft Au is preferable as the bump material.

In this embodiment, the solder film is formed on the substrate side because the subsequent heat treatment is only an ashing process for removing the resist residue. Accordingly, since little heat is applied to the solder film, the surface oxidation of the solder film can be suppressed, which is preferable. By the way, when forming a solder film on the optical element side, in the current process, a bar-shaped optical element array is made by cleaving from the wafer, and this cleaved surface is AR coated (anti-reflective film) or HR coat (reflective film) At this time, a long-term heat history is applied at a high temperature. Therefore, when solder is formed on an optical element in a wafer state before dicing, the heat history tends to oxidize the solder surface and deteriorate the wettability.

However, due to the size relationship between the substrate and the optical element, the optical element is smaller in size and can be obtained from a single wafer in a larger number. Therefore, when a solder film is formed on the optical element side, the number that can be obtained in one vapor deposition is larger,
That is, a small number of depositions is required to obtain a desired number,
This leads to improvement in overall production efficiency.

In this embodiment, the solder film has a laminated structure of the Sn layer and the Au layer. This is because when the Sn is exposed on the surface, the Sn is oxidized and the wettability of the solder is deteriorated. By using a laminated structure in which the Sn layer is wrapped around the Au layer, oxidation is prevented. In the connection of the optical element, if a flux is used, there is a possibility that the optical path may be closed due to the residue. Therefore,
If an oxide film is formed on the solder surface, poor wetting is likely to occur.

In this embodiment, an An-Sn solder is mainly used, because the Au-Sn solder has excellent creep characteristics. Creep is a phenomenon in which a metal is gradually deformed when a small load is applied to a solder for a long period of time. Since the optical element generates heat with light emission, the solder must be resistant to creep deformation, so that Au-Sn solder is preferable. A typical composition of Au-Sn solder is Au-
20 wt% Sn (Au-Sn eutectic composition), and Au-Sn solder having a composition in the vicinity of this is often used for connection of optical elements. The composition of the solder after connection varies depending on the Au thickness of the electrode metallization of the element and the substrate, but is often between Au-10% by weight Sn and Au-37% by weight Sn. The Au-Sn solder in this composition range has excellent creep properties, but is harder than other Pb-Sn eutectic solders. Accordingly, a relatively large stress may be generated in the optical element due to the connection (residual stress caused by a difference in the coefficient of thermal expansion between the optical element and the substrate), and a soft Sn-Ag solder is used to reduce this. May be used. In this case, it is necessary to consider the displacement of the optical element due to creep.

The material constituting the solder film is as follows.
It is important to be difficult to oxidize, to be able to control the thickness, to be able to control the composition, and to be resistant to creep deformation. In view of these, a solder film having a laminated structure of Au / Sn / Au by vapor deposition is suitable. As described above, Sn-Ag or the like may be used for an optical component in which creep is not a serious problem (a component such as glass which does not generate heat).

With the above connection structure and connection method, the optical module shown in FIGS. 1 to 5 is manufactured. Here, the operation of the optical module of this embodiment will be described.
As shown in FIG. 3, each of the optical elements 20 to 22 is provisionally connected on the substrate, and then solder connection is performed. Light emitted from the front of the LD element 23 enters the waveguide 3 and is transmitted to the outside through the waveguide 3. Light emitted from the rear of the LD element 23 is received by the mPD element 22 and used for controlling the output of the LD element 23. On the other hand, an optical signal transmitted from the outside passes through the waveguide 3 and is received by the PD element 21. The PD device 21 converts the optical signal into an electric signal. As described above, the optical module having the transmission and reception functions as in this embodiment can be manufactured.

A second embodiment of the present invention will be described with reference to FIG. A nucleus 13 is made of a soft metal such as silver, copper, nickel, platinum, lead, or aluminum or a polyimide resin inside the temporary connection bump, and an Au layer 14 is formed on the surface thereof.
Is formed. With such a configuration,
The consumption of expensive Au can be suppressed, and the cost can be reduced. This embodiment shows the case of an LD element,
In the case of the D element and the PD element, the temporary connection bumps can have the same structure. If an adhesive resin is used, temporary connection can be performed using only the resin, but the height of the temporary connection bumps determines the height of the optical element. No. The height of the Au bump can be accurately adjusted by the flattening process.
The height can be easily adjusted by forming the layer 14.

A third embodiment of the present invention will be described with reference to FIG. This is a state in which Au bumps 9 and 15 for temporary connection are formed on both the substrate 1 and the optical element 20, and these are temporarily connected and then soldered. When a thick Au bump cannot be formed on the substrate, the Au bump may be formed on the element side in this way, and the optical element does not shift during melting of the solder as in the other embodiments. Further, in this embodiment, the case of the LD element is illustrated, but the mPD element and the P element are used.
In the case of the D element, the same effect as in the present embodiment can be obtained by using the same structure for the temporary connection bumps.

When the connection bumps are formed on both sides of the substrate and the optical element in this manner, a necessary and sufficient gap can be formed between the optical element and the substrate. To prevent the temporary connection by the bump from becoming insufficient. If a large bump cannot be formed on one side, a sufficient gap can be formed between the substrate and the element by forming it on both sides.

A fourth embodiment of the present invention will be described with reference to FIGS. In this embodiment, the Au-Sn solder 12
Are formed not on the substrate side but on the LD element 20 side.
By heating in this state to melt the Au-Sn solder 12, the melted solder is repelled by the surface of the element 20 and wets the electrode metallization 25 to form a sphere, as shown in FIG. 7 is also contacted and connected. Although the present embodiment also illustrates the case of an LD element, in the case of an mPD element and a PD element, the solder film 12 is formed on the electrode metallization 26 to have the same structure as that of the LD element. The same effect as described above can be obtained.

A fifth embodiment of the present invention will be described with reference to FIG. The connection structure of this embodiment is the same as the connection structure of the first embodiment, but this connection structure is applied to a trunk optical communication module. In a trunk-line module, it is necessary to put light into a fiber with high efficiency for long-distance communication, and a lens is often used. In this embodiment, an inverted pyramid-shaped groove 31 for mounting a ball lens 32 on a substrate 30 is formed.
2 in the groove, and the LD element 20 and the mPD element 22
Is fixed on the substrate. As in the first embodiment, first, the substrate side index 4 is matched with the index of the optical element, and then the optical elements 20 and 22 are pressed against the temporary connection bumps 9 and temporarily connected, and then the entire substrate is soldered.
Then, the solder 12 is melted by heating to a temperature equal to or higher than the melting point of 2, and the connection is made according to the same principle as in FIG. In the case of the present embodiment, the ball lens 32 is formed with an inverted pyramid-shaped groove 3 using an adhesive or the like.
It is fixed in 1. The method of fixing the ball lens is
It is not limited to adhesives, but can be fixed with solder,
Alternatively, it is also possible to fix by pressure bonding to Al metallization. In this case, metallization for solder connection is formed in the groove 31 and the ball lens 32 in advance,
It is necessary to form Al metallization in the groove 31.
In the optical module of this embodiment, an optical signal emitted from the front of the LD element 20 is condensed by the ball lens 32 and is incident on the fiber. On the other hand, an optical signal emitted from the rear of the LD element 20 is received by the mPD element 22 and used for controlling the LD element 20.

As described above, the present invention can be applied to both the subscriber-system and trunk-system optical modules, and can manufacture optical modules with a high yield and provide a low-cost optical module.

The solder material for fixing the optical element and the substrate described above is not limited to the Au-Sn solder. In the embodiment shown in FIGS. 1 to 10, Sn and Ag are used.
The solder film may be composed of a solder material containing Cu as a main component and adding Cu as needed, or a solder material containing Sn and Bi as a main component and adding Ag as needed. An example in which a solder material other than Au-Sn is used will be described below.

A sixth embodiment of the present invention will be described with reference to FIG. FIG. 11 illustrates a structure for temporarily fixing optical components 33 such as a lens, a filter, and an isolator on the substrate 1 with the temporary connection bumps 9 and then melting and connecting the Sn-3.5Ag solder 17. is there. FIG. 12 shows a state where the optical component 33 is temporarily fixed to the temporary connection bumps 9. A metallization 34 for provisional connection and a metallization 35 for solder connection are also formed on the lower surface of the optical component 33. In FIG. 12, the metallization 34 for provisional connection and the bump 9 for provisional connection are fixed by close contact. In this state, Sn-3.5Ag solder 17
When heated to a melting point of 221 ° C. or higher, the Sn-3.5Ag solder 17
Melts and collects on the connection metallization 18 of the substrate.
This is because the molten solder is repelled at places other than metallization. As a result, as described in the first embodiment, the height of the solder increases according to exactly the same principle as in FIG. 5, the solder wets the metallization 35 on the optical component side, and the optical component 33 Fixed. The solder material 17 is not limited to Sn-3.5Ag, and Cu may be added as necessary, or a solder material containing Sn and Bi as main components and adding Ag as necessary may be used. it can. For example, Sn- (3-5) Ag- (0-0.8) Cu,
Alternatively, a solder material such as Sn-57Bi- (0-5) Ag is preferable.

Although the embodiments described so far relate to the mounting of a module for optical communication, the present invention is not limited to the mounting of an optical module, but is extremely effective in forming an optical circuit on a substrate. It is.

A seventh embodiment of the present invention will be described with reference to FIGS. Wafer 3 on which an optical waveguide composed of cladding layer 2 and core 3 is formed in advance
6, the optical element 37 is fixed on the substrate 36 via the temporary connection bumps 9, and then the solder 38 is melted.
9, the optical element 37 and the wafer 36 are connected. As in this embodiment, by mounting an optical element on a substrate on which an optical waveguide is formed and forming an optical circuit, information transmission can be speeded up and the capacity can be increased. Therefore, by forming an optical circuit as in this embodiment on a part of the substrate of the electronic circuit device and connecting it to another electronic circuit device, information transmission between the electronic circuit devices can be speeded up and the capacity can be increased. be able to.

In mounting a large number of optical elements on a substrate as described above, all the optical elements and the waveguide must be optically coupled. In the prior art, such a large-sized optical circuit substrate is used. However, in many cases, poor coupling often occurs at some optical element, and the yield is greatly reduced. However, according to the present invention, the optical element can be temporarily fixed on the wafer and soldered without moving the optical element, so that such an optical circuit can be manufactured with high yield.
Furthermore, even when such an optical circuit is cut into a small circuit, the optical elements can be connected collectively on the wafer, so that the time and labor required in the mounting process can be significantly reduced, The cost of the optical circuit can be reduced.

As described above, the optical element or optical component is temporarily fixed on the substrate by the temporary connection bumps and then fixed by soldering, so that the optical element or optical component is positioned and heightened when the solder is melted. These can be mounted with high accuracy without changing the horizontality and the like. As a result, the yield in the mounting process is improved, and a low-cost optical module can be provided. Furthermore, even when an optical circuit is formed on a wafer such as Si and many optical elements and optical components are fixed by soldering, the optical elements and optical parts are temporarily fixed on the Si wafer, and then the wafer is heated collectively By doing so, an optical circuit can be formed. In addition, since the optical elements can be fixed collectively, the time required in the manufacturing process can be reduced, and a low-cost optical module can be provided.

[0040]

According to the present invention, it is possible to provide an optical module in which mounting accuracy of optical elements and optical components is improved in passive alignment mounting.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an embodiment of the present invention.

FIG. 3 is a diagram showing an embodiment of the present invention.

FIG. 4 is a diagram showing an embodiment of the present invention.

FIG. 5 is a diagram showing an embodiment of the present invention.

FIG. 6 is a diagram showing an embodiment of the present invention.

FIG. 7 is a diagram showing an embodiment of the present invention.

FIG. 8 is a diagram showing an embodiment of the present invention.

FIG. 9 is a diagram showing an embodiment of the present invention.

FIG. 10 is a diagram showing an embodiment of the present invention.

FIG. 11 is a diagram showing an embodiment of the present invention.

FIG. 12 is a diagram showing an embodiment of the present invention.

FIG. 13 is a diagram showing an embodiment of the present invention.

FIG. 14 is a diagram showing an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Optical waveguide clad layer, 3 ... Optical waveguide core, 4 ... Substrate side index, 5 ... Electric wiring, 6 ... Wire bonding pad, 7 ... Substrate side electrode metallization,
8: Metallization for temporary connection bumps on the substrate side, 9: Bump for temporary connection, 10: Au film for solder material, 11: Sn film for solder material, 12
... Solder film, 13 ... Au-Sn solder, 14 ... Silver,
Nuclei of temporary connection bumps made of a soft metal such as copper, nickel, platinum, lead, or aluminum, or polyimide resin, 15 ... Au layer on the surface, 16 ... temporary connection bumps on the optical element side, 17 ... Sn- 3.5Ag solder, 18 ... metallization for connection, 20 ... LD element, 21 ... PD element, 22 ... mPD element, 23 ... Optical element side wire bonding pad, 24
... Metallized for temporary connection on the optical element side, 25... Metallized for LD element electrode, 26... Metallized for PD element electrode, 30... Substrate having an optical component mounting part, 31. Lens, 33 ...
Optical parts, 34 ... Metallization for temporary connection on the optical parts side, 35
... Metallized for solder connection on the optical component side, 36. Si wafer, 37. Optical element, 38. Solder before melting, 39. Solder after melting

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 31/02 H05K 3/34 512C H01S 5/026 H01L 21/92 602E H05K 3/34 505 603B 512 23 / 12F 31/02 B F term (reference) 2H037 AA01 BA02 BA03 BA11 BA12 BA21 DA03 DA12 DA17 DA18 5E319 BB01 BB04 CC33 5F044 KK16 KK18 QQ01 QQ03 5F073 CB23 FA02 FA08 FA22 FA27 5F088 AA01 BA16 EA09 EA16

Claims (9)

[Claims] An optical module comprising: a substrate; and an optical element mounted on the substrate, a solder layer formed on at least one of the substrate and the optical element, and at least one of the substrate and the optical element. Comprising a bump formed on one of the two sides, connecting the substrate and the optical element via the bump, and then melting the solder layer to solder-connect the substrate and the optical element. Characteristic optical module. 2. The optical module according to claim 1, wherein an optical component is mounted on said substrate instead of said optical element. 3. The optical module according to claim 1, wherein the bump is made of a material having a higher melting point than a solder material forming the solder layer. 4. The light according to claim 1, wherein the optical element or the optical component includes a metallization for connecting to the bump and a metallization for connecting to the solder layer. module. 5. The bump according to claim 1, wherein the bump is made of any one of gold, silver, copper, nickel, platinum, lead and aluminum, or an alloy containing these metals as a main component. The optical module according to any one of claims 1 to 4, 6. The optical module according to claim 5, wherein an Au layer is formed on a surface of said bump. 7. The bump according to claim 1, wherein an Au layer is formed on the surface of a heat-resistant organic substance, or at least another metal, an organic substance, or an inorganic substance is dispersed in Au. The optical module according to any one of claims 1 to 4, 8. The optical module according to claim 1, wherein said solder layer is formed by laminating an Au layer and a Sn layer. 9. The method according to claim 9, wherein the solder connected to the solder is An-S.
n-based solder, Sn-Ag-based solder, or S
The optical module according to any one of claims 1 to 8, wherein the optical module is an n-Ag-Cu solder or a Sn-Ag-Bi solder.