JPH0878657A - Opto-electric hybrid mounting board, manufacturing method and opto-electric hybrid integrated circuit - Google Patents

Abstract

PURPOSE: To provide an optical integrated circuit with small loss in optical waveguide function, and advantages in optical bench function and high-frequency wiring function, by forming an optical element mounting part made up of a projected terrace on a circuit board and an electric wiring part made up of a dielectric layer and a conductive pattern put on a surface or an inner part of the dielectric layer. CONSTITUTION: An upper projected face part of a silicon substrate 1 is used as a silicon terrace 30 for mounting an optical element. An optical fiber 31 as an optical waveguide is held adequately in an optimum position in a V-shaped groove of a silicon terrace part 30. An Au-Sn solder on a thermal oxide film on the face of the silicon terrace 30 is patterned to form a thin-film electrode 52 fixed in a state of contact with a surface electrode of an optical function element on the silicon terrace 30. The thin-film electrode 52 is connected electrically to surface-electrode conductive patterns 51a and 51b on a face of a dielectric layer 50 formed in a recessed part of an electric wiring part on the silicon substrate 1. In addition, the dielectric layer 50 is embedded around an electric circuit silicon terrace 35, and an electric circuit conductive pattern 51 is formed on the face of the silicon terrace 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid optical integrated substrate on which an optical element or an optical submodule used for optical communication or optical signal processing can be mounted in addition to an optical waveguide and electric wiring, a method for producing the same, and the substrate. The present invention relates to an optical sub-module that can be mounted on the above, and a hybrid optical integrated circuit in which an optical element or an optical sub-module is mounted on the substrate.

[0002]

2. Description of the Related Art With the recent advancement of optical communication and optical information processing, it is expected that a hybrid optical / electronic integrated circuit in which an active optical element is incorporated in a low-loss optical waveguide and driven by a high frequency electric circuit is realized. There is.

In order to realize a circuit for driving a high frequency by incorporating an active optical element on this optical waveguide, 1. a low loss optical waveguide function, 2. an optical element mounted on the same substrate to prevent axis deviation Optical bench function for the purpose, 3. high-frequency electrical wiring function required to drive the optical element
It is required as an electrical mounting board.

However, in the conventional technique, a circuit satisfying the above three conditions has not been obtained.

As a conventional example, FIG. 1 utilizes the guide groove 2 and the positioning reference surfaces 3a, 3b and 3c formed on the Si substrate 1 to form an optical fiber 4 and a semiconductor laser (LD) 5 on the Si substrate 1. FIG. 3 is a perspective view showing a structure called “Si optical bench” which is intended to be integrated with and is driven by electric wiring 6. In this configuration, since the guide groove 2 can be accurately formed by utilizing the good workability of the Si substrate 1, the optical fiber 4 and the optical element such as the semiconductor laser (LD) 5 and the photodetector (PD) can be integrated. Easy to implement. Further, since the Si substrate has excellent thermal conductivity, it also functions as a good heat sink with the optical element.

The electric wiring 6 is formed directly on the surface of the Si substrate 1 or through an extremely thin oxide film having a thickness of 0.5 μm or less. This structure has high frequency characteristics of the electric wiring 6. It causes a problem of remarkable deterioration. That is, in order to form the electric wiring 6 having excellent high frequency characteristics, it is necessary to make the thickness of the electric wiring layer sufficient and to form the electric wiring layer on an insulator having a small dielectric loss. Has a very small thickness and has a high specific resistance of about 1 kΩ · cm so as to compensate for sufficient high frequency characteristics.

FIG. 2 shows the high frequency characteristics of a 0.6 mm long coplanar wiring formed directly on a Si substrate (T. Suzaki et al .: Microvav).
e Workshop Digest (1993) P9
5). The vertical axis represents transmission characteristics S21 of S parameter, and the horizontal axis represents frequency (GHz). The loss of the wiring of 0.6 mm length is about 0.4 dB (2 GHz), about 0.8 dB (10 GHz).
z), which is 7 dB (2 GH when converted to a length of 1 cm)
z) and 13 dB (10 GHz), resulting in a large loss.

On the other hand, as an optical mounting substrate having an optical waveguide function, application of a silica optical waveguide formed on a Si substrate is expected. The conventional optical waveguide is shown in FIGS.
As shown in (D), there are two types: 1. "ridge type optical waveguide" in which the core is protected by a thin overclad layer, and 2. "embedded optical waveguide" in which the core is embedded with a sufficiently thick overclad layer. There is.

FIG. 4 shows a study example of a ridge type optical waveguide (6. Y. Yamada et al., “Hybri”).
d-Integrated 4x4 Optical
Gate Matrix Switch Using
Silica-Based Optical Wave
guides and LD Array Chip
s ", IEEE J. Lightwave Techn
ol. , Vol. 10, pp. 383-390, 199
2. ), Which is caused by the warp of the substrate due to the thickness of the silica-based optical waveguide 7 formed on the Si substrate 1 and the semiconductor optical element 8 (semiconductor laser amplifier: SLA in this example). Leads to an increase in

More specifically, in Table 2, with respect to the thickness H dependency, the loss of high frequency electrical wiring is 1.0 dB in general.
/ Cm or less, and considering the wide range of uses of the hybrid substrate of the present embodiment, it is considered to be 1.5 dB / cm or less. From Table 2, the loss is 1.
In order to be 5 dB / cm or less, the total thickness H of the quartz layer is 5
It must be 0 μm or more.

Further, in order for the hybrid substrate to maintain a good optical bench function, it is necessary that the substrate warp is small. In FIG. 18, the silica optical waveguide layer and the Si substrate 1 mean that the application field of the thermal expansion waveguide is limited to a narrow region. Thus, the ridge type optical waveguide does not sufficiently fulfill the optical waveguide function. Moreover, the electric wiring function is not examined here.

Further, FIG. 5 shows an "optical waveguide substrate with a terrace" in which an optical waveguide is formed in a concave portion 1a on a Si substrate 1 having irregularities, and the convex portion 1b is used as an element mounting portion (Yamada, Kawachi, Kobayashi: Japanese Patent Laid-Open Publication No. 2000-242242). 63-131104 "Hybrid Optical Integrated Circuit"). In FIG. 5, an under-cladding layer 10c of the silica-based optical waveguide 10 is formed in the recess 1a of the Si substrate 1, a core layer 10b is formed thereon, and finally a buried cladding layer 10a is formed. ing. And the upper surface of the under cladding layer 10c,
The heights of the upper surfaces of the convex portions 1b of the Si substrate 1 are the same, and the convex portions 1b can be used as the height reference plane of the optical element 8. In such a substrate 1, the low-loss optical waveguide function and the optical bench function are satisfied, but the function of mounting high-frequency electrical wiring has not been studied at all. Here, even if the electric wiring is mounted, it is formed on the convex portion 1b of the Si substrate 1, and does not satisfy the requirement for high frequency characteristics. In FIG. 5, 8a is an active layer, and 11 is a reference plane for element positioning.

FIG. 6 is a perspective view showing the configuration of the hybrid optical integrated circuit disclosed in Japanese Patent Laid-Open No. 62-242362. This circuit includes a buffer layer 12 provided on the Si substrate 1 and a silica-based optical waveguide 13 provided on the buffer layer 12.
And the height from the upper surface of the Si substrate 1 is the buffer layer 12
The same element holding base 14, a semiconductor laser 15 held on the holding base 14 in an upside-down configuration, an upper surface electrode (not shown) of the semiconductor laser 15 and a conductive wire electrically connected by a gold wire W. The electrical wiring board 16 has a film 16a and is provided on the upper surface of the Si substrate 1 so as to project therefrom. Reference numeral 17 is a heat sink.

In the circuit having such a configuration, the buffer layer 1
2 from the upper surface of the device holding base 14 to the active layer 15a of the semiconductor laser 15
Since the height difference is set to be equal to the height difference, there is an advantage that an optical element such as the semiconductor laser 15 can be mounted with extremely high positioning accuracy.

However, even in this circuit, the optical waveguide 13 is limited to the ridge type, which is easily affected by disturbances and the like, and the optical waveguide function of low loss cannot be exhibited.

FIG. 7 is a perspective view showing the structure of the hybrid optical integrated circuit disclosed in Japanese Patent Publication No. 5-3748. This circuit comprises an optical waveguide 18, an optical fiber guide 19, an optical element guide 20 and an electric wiring support 21 which are arranged in a convex shape having substantially the same height on the Si substrate 1, and a first circuit arranged on the Si substrate 1. One conductive film (common electrode) 22, a second conductive film 23 disposed on the upper surface of the electric wiring support 21 and insulated from the first conductive film 22, and the optical fiber guide 1
The optical fiber 24 is provided along the optical element guide 20, and the laser diode 25 as an optical element is provided along the optical element guide 20.

In the circuit having such a structure, since the optical element is directly mounted on the Si substrate 1, there is an advantage that the Si substrate 1 can function as a heat sink.

However, even in this circuit, the optical waveguide 18 is limited to the ridge type, which is easily affected by disturbances and the like, and the optical waveguide function of low loss cannot be exhibited.

FIG. 8 is a sectional view showing the structure of an optical semiconductor device disclosed in Japanese Patent Laid-Open No. 5-60952. This device is roughly composed of a Si substrate 1, an optical waveguide 26 formed on the substrate 1, and an optical semiconductor element 27 mounted in a recess of the Si substrate 1 in an upside down configuration.

In the device having such a structure, the optical waveguide 26
Is formed on the convex region of the Si substrate 1, the underclad having a sufficient thickness cannot be formed. For this reason, the transmission loss is large, and it is easily affected by disturbances, so that the optical waveguide function is not sufficient.

Further, in the above device, since it is provided on the Si substrate 1 from the electric wiring portion 28, it does not satisfy the requirements for high frequency characteristics.

As described above, no conventional hybrid optical integrated technology satisfies the above three requirements. In particular, the high frequency electrical wiring function has hardly been considered.

[0023]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hybrid optical integrated circuit satisfying a low loss optical waveguide function, an optical bench function and a high frequency electric wiring function, an optical mounting substrate and an optical submodule applicable to the circuit. To provide.

[0024]

In order to achieve the above object, an invention according to claim 1 is a mounting board including an optical waveguide portion, an optical element mounting portion, and an electric wiring portion provided on the same substrate. The optical element mounting portion is composed of a terrace provided in a convex shape on the substrate, and the electric wiring portion is composed of a dielectric layer formed on the substrate and a conductor pattern formed on the surface or inside thereof. It is characterized by

Here, the invention according to claim 2 is the same as claim 1
In the optical / electronic hybrid mounting substrate, the terrace may be made of Si.

According to a third aspect of the present invention, in the optical / electronic hybrid mounting substrate according to the second aspect, the substrate has a Si terrace for mounting the optical element and a Si terrace for forming an electronic circuit. You may.

The invention according to claim 4 is the invention according to claim 2 or 3.
In the optical / electronic hybrid mounting board, the height of the conductor pattern upper surface on the dielectric layer is set to be lower than the Si terrace upper surface at least near the Si terraces of the optical element mounting portion and the electric wiring portion. Good.

According to a fifth aspect of the present invention, in the optical / electronic hybrid mounting substrate according to the fourth aspect, the Si terrace has a side surface having an inclination angle, and thin film electrodes are provided on the surface and the side surface of the Si terrace. The thin film electrode formed may be electrically connected to a conductor pattern formed on the upper surface of or inside the dielectric layer around the Si terrace.

The invention according to claim 6 is the invention according to claim 4 or 5.
In the optical / electronic hybrid mounting substrate described in (1) above, the Si terrace for an optical element is divided into two or more, and the space between the divided Si terraces is filled with the dielectric layer. A conductor pattern may be provided on the dielectric layer between the Si terraces.

According to a seventh aspect of the present invention, in the optical / electronic hybrid mounting substrate according to any one of the first to sixth aspects, the optical waveguide portion has a positioning groove formed on the Si terrace, and the positioning groove. It may include an optical fiber fixed in the groove.

According to an eighth aspect of the present invention, in the optical / electronic hybrid mounting substrate according to any one of the first to sixth aspects, the optical waveguide section includes an under cladding layer, a core and an overclad layer formed on the substrate. The height of the bottom surface of the core of the optical waveguide may be set higher than the upper surface of the Si terrace.

The invention according to claim 9 is the invention according to claim 7 or 8.
In the optical / electronic hybrid mounting substrate described in (1), the optical waveguide includes one or more signal optical waveguides and one or more monitor optical waveguides, and the optical element Si terrace includes:
It may be provided at a position corresponding to the input / output end of the monitor optical waveguide, and thin-film electrical wiring may be formed on the surface of the Si terrace for the optical element.

According to a tenth aspect of the present invention, in the optical / electronic hybrid mounting substrate according to the eighth aspect, the optical waveguide is a dielectric optical waveguide, and the dielectric layer of the electric wiring portion is the dielectric optical waveguide. The under clad layer may be used.

According to a tenth aspect of the present invention, in the optical / electronic hybrid mounting substrate according to the tenth aspect, an optical waveguide is formed on a part of the first dielectric layer formed of the underclad layer of the optical waveguide. A second dielectric layer made of a different material may be laminated, and a conductor pattern may be formed inside or on the surface of the second dielectric layer.

According to a twelfth aspect of the present invention, in the optical / electronic hybrid mounting substrate according to the tenth aspect, the substrate is a Si substrate, and both the optical waveguide and the electric wiring portion dielectric layer are quartz optical waveguides. The conductor pattern which is formed and is formed on the electric wiring portion dielectric layer is a coplanar wiring including a center conductor and a ground conductor, and the thickness of the dielectric layer may be 50 μm or more.

According to a thirteenth aspect of the present invention, in the optical / electronic hybrid mounting substrate according to the tenth aspect, the Si substrate has a specific resistance of 50 Ωcm or more on average, and the optical waveguide and the dielectric layer are: The conductor pattern is mainly formed of a quartz waveguide, and the conductor pattern provided on the dielectric layer of the electric wiring portion is a coplanar wiring composed of a center conductor and a ground conductor, and the thickness of the dielectric layer is 20 μm or more. Good.

According to a fourteenth aspect of the present invention, there is provided a silica-based optical waveguide comprising an under-clad, a core and an over-clad formed on a Si substrate, and one of the over-clad and the under-clad of the silica-based optical waveguide. An optical / electronic hybrid mounting substrate, which is adhered to the substrate and includes an electric wiring layer having a coplanar wiring composed of a central conductor and a ground conductor, wherein quartz having a thickness of 50 μm or more is provided between the electric wiring layer and the Si substrate. It is characterized in that it is a system optical waveguide.

According to a fifteenth aspect of the present invention, there is provided a silica-based optical waveguide comprising an under-clad, a core and an over-clad formed on a Si substrate, and one of the over-clad and the under-clad of the silica-based optical waveguide. In the optical / electronic hybrid mounting substrate, which is adhered to the substrate and includes an electric wiring layer having a coplanar wiring composed of a central conductor and a ground conductor, the Si substrate has an average specific resistance of 50 Ωcm or more. A silica optical waveguide having a thickness of 20 μm or more is formed between the Si substrate and the Si substrate.

The invention according to claim 16 is defined by claims 11 to 1.
5. The optical / electronic hybrid mounting board according to any one of 5 above, wherein the thickness of the entire silica-based optical waveguide is 120 μm.
It may be m or less.

The invention according to claim 17 is the invention according to claims 8 to 16.
In the optical / electronic hybrid mounting substrate according to any one of 1 above, the substrate is a Si substrate having a concave portion and a convex portion formed on its surface, and the Si substrate convex portion functions as the Si terrace, and the optical waveguide Is an optical waveguide comprising an under-cladding layer, a core, and an over-cladding formed in the Si substrate recess, and the electric wiring portion is a dielectric layer formed on the Si substrate recess and a conductor pattern provided on the surface or inside thereof. You may comprise.

The invention according to claim 18 is the invention according to claims 1 to 11.
In the optical / electronic hybrid mounting board described in any one of 1 above, a conductor pattern is formed inside the board, and the conductor pattern inside the board and the conductor pattern inside or on the dielectric layer are electrically connected to each other. May be connected to.

According to a nineteenth aspect of the present invention, in the optical / electronic hybrid mounting substrate according to the first aspect, the optical waveguide portion is an optical waveguide including an under-cladding layer, a core and an over-cladding layer formed on the substrate. The height of the bottom surface of the core of the optical waveguide is set to be higher than that of the upper surface of the Si terrace, and the electric wiring portion conductor pattern is formed to have a thickness substantially equal to that of the surface of the optical waveguide over clad. It may be provided on the surface of the above-mentioned dielectric layer.

The twentieth aspect of the present invention is a method of manufacturing an optical / electronic hybrid mounting substrate, comprising convex Si on the substrate.
A step of providing a terrace, a step of flattening the surface after forming an optical waveguide under-cladding layer on the substrate, a step of forming a core pattern and an over-cladding layer, an over-cladding of the Si terrace portion and the electric wiring portion. layer,
By removing all of the core and part of the underclad layer to form the element mounting portion, the upper surface of the Si terrace is exposed and the surface of the underclad layer in the electric wiring portion region is made lower than the Si terrace surface by a desired dimension. The method is characterized by including a step of setting and a step of forming a conductor pattern on the electric wiring portion.

According to a twenty-first aspect of the present invention, which is an optical / electronic hybrid integrated circuit, the optical waveguide including an under-cladding layer, a core and an over-cladding layer provided on the substrate, and the substrate adjacent to the optical waveguide. An electrical wiring portion including a Si terrace functioning as an element mounting portion provided in a convex shape upward, and a dielectric layer formed on the substrate adjacent to the Si terrace and a conductor pattern provided on the surface or inside thereof On the mounting substrate composed of and on the Si terrace for the optical element,
With the optical element surface facing downward, at least a part of the optical element surface is in contact with the Si terrace upper surface, optical coupling is maintained with the optical waveguide, and electrical contact is made with the conductor pattern of the electrical wiring portion. It is characterized in that an optical functional element is mounted while keeping it.

According to a twenty-second aspect of the present invention, which is an optical / electronic hybrid integrated circuit, the optical waveguide including an under-cladding layer, a core and an over-cladding layer provided on the substrate, and the substrate adjacent to the optical waveguide. An optical element Si terrace functioning as an optical element mounting portion provided in a convex shape upward, and a dielectric layer formed on the substrate adjacent to the optical element Si terrace and a conductor provided on the surface or inside thereof The Si for optical device is formed on a mounting substrate composed of an electric wiring portion formed of a pattern and a Si terrace for an electronic circuit functioning as an electronic circuit mounting portion provided in a convex shape on the substrate in the electric wiring portion region. On the terrace, with the optical element surface facing downward, at least a part of the optical element surface is in contact with the Si terrace upper surface, optical coupling with the optical waveguide is maintained, and a conductor pattern of the electric wiring portion is maintained. Electrical contact with Keeping while, optical functional device is Yes is mounted, the Si terrace for electronic circuit, the electronic circuit is the Si
It is characterized by being mounted while maintaining thermal connection with the terrace.

According to a twenty-third aspect of the present invention, in the optical / electronic hybrid integrated circuit according to the twenty-second aspect, the height of the conductor pattern upper surface on the dielectric layer near the Si terrace for the electronic circuit is the upper surface of the Si terrace for the electronic circuit. Set lower,
A part of the electronic circuit is held in contact with the electronic circuit Si terrace, and at least a part of the electrode on the surface of the electronic circuit has a conductor pattern on the dielectric layer corresponding to the electrode. Alternatively, they may be fixed while maintaining electrical connection through a conductive bonding material.

The invention as defined in claim 24 is defined by claim 21 and claim 2.
3. The optical / electronic hybrid integrated circuit according to any one of 3 above, wherein the optical functional element is provided with a concavo-convex surface and a conductor pattern in an electrically connected state from the concave surface to the convex surface. The back surface electrode of the optical functional element is contact-fixed on the recess of the subcarrier made of a heat conductive material in a state of being electrically connected to the conductor pattern, and the Si terrace is divided into two or more. The space between the formed Si terraces is filled with the dielectric layer, and the first conductor pattern for the electrode provided on the surface of the active layer side surface of the optical functional element on the dielectric layer around the Si terrace and the light A second conductor pattern corresponding to the functional element back surface electrode is provided, and the height of the upper surfaces of the first and second conductor patterns is
The optical functional element, which is set lower than the upper surface of the i-terrace and is fixed to the subcarrier, keeps the peripheral portion of the optical element surface in contact with and thermally connected to the Si-terrace surface with the element surface facing downward. While being mounted on the mounting substrate, the surface electrode of the optical functional element and the first conductor pattern are electrically connected via a conductive bonding material, and the back electrode of the optical functional element is the subcarrier. It may be in electrical contact with the second conductor pattern via the conductor pattern on the convex portion and the conductive bonding material.

The invention of claim 25 is the same as claims 21 to 2.
3. The optical / electronic hybrid integrated circuit according to any one of 3 above, wherein the optical functional element has a surface provided with unevenness and is provided with a conductor pattern in a state of being electrically connected from the concave surface to the convex surface. The back surface electrode of the optical functional element is contacted and fixed on the concave portion of the subcarrier made of a conductive material in a state of being electrically connected to the conductor pattern, and the Si terrace is divided into two or more and has an inclination angle of The surface of the divided Si terrace is filled with the dielectric layer, and is provided on the dielectric layer around the Si terrace on the surface of the active layer side of the optical functional element. The first conductor pattern corresponding to the electrode is provided, and the height of the first conductor pattern upper surface is set lower than the Si terrace upper surface, and the Si terrace upper surface and a part of the inclined side surface are provided. Is the above light machine A thin film electrode corresponding to the device back surface electrode is formed, and the thin film electrode is electrically connected to the second conductor pattern provided on the dielectric, and the optical functional device fixed to the subcarrier is the device surface. And the peripheral portion of the optical element surface is mounted on the mounting substrate while maintaining contact and thermal connection with the Si terrace surface in a state in which the optical functional element surface electrode and the first conductor pattern are The back electrode of the optical functional element is electrically connected through a conductive bonding material, and the back electrode of the optical functional element is connected to the second conductor pattern via the conductor pattern on the convex portion of the subcarrier and the thin film electrode on the Si terrace. It may be in electrical contact.

According to a twenty-sixth aspect of the present invention, in the optical / electronic hybrid integrated circuit according to the twenty-fourth or twenty-fifth aspect, in the optical functional device fixed to the subcarrier, the optical functional device is activated from the outer surface of the subcarrier. It is formed so that the distance to the layer becomes a desired set value D,
A guide structure made of the optical waveguide material is provided near the Si terrace, and the distance from the inner surface of the guide structure to the center of the optical waveguide core is set to be the set value D. The optical functional element may be mounted on the Si terrace while keeping the outer surface of the subcarrier in contact with the inner surface of the guide structure.

The invention of claim 27 is the same as claims 21 to 2.
5. The optical / electronic hybrid integrated circuit according to any one of 5 above, wherein the optical waveguide includes one or more signal line optical waveguides and one or more monitor optical waveguides, and the optical functional element includes: A signal port and a monitor port formed at positions corresponding to the signal light guide and the monitor light guide, respectively, on the mounting board; and a monitoring light waveguide of the mounting board and a monitor port of the optical function element. May be optically coupled, and at the same time, the optical functional element may be installed on the Si terrace on the mounting substrate in a state where the signal optical waveguide and the signal port are optically coupled.

The invention as defined in claim 28 is an optical / electronic hybrid integrated circuit, which is formed on a substrate and has at least one signal optical waveguide and at least one monitor optical waveguide. Portion, an optical element mounting portion provided in an end portion of the optical waveguide portion or in a void portion provided in the optical waveguide portion of the optical waveguide portion, and the signal optical waveguide provided in the optical waveguide portion, An optical functional element having a signal port and a monitor port for optically coupling to the monitor optical waveguide, wherein the monitor optical waveguide of the optical waveguide portion and the monitor port of the optical functional element are optically coupled, and at the same time, the optical waveguide portion. The optical functional element is mounted on the optical element mounting portion in a state where the signal optical waveguide and the signal port of the optical functional element are optically coupled.

According to a twenty-ninth aspect of the present invention, in the optical / electronic hybrid integrated circuit according to the twenty-fifth aspect, the other waveguide end of each of the monitor optical waveguides optically coupled to the monitor port is connected to the optical / electronic hybrid optical circuit. It may be guided to the end of the hybrid mounting board.

According to a thirtieth aspect of the present invention, in the optical / electronic hybrid integrated circuit according to the twenty-fifth aspect, two or more optical functional elements are mounted in tandem on the optical / electronic hybrid mounting substrate. The monitor port of each optical function element has a monitor optical waveguide connecting the optical function element monitor port and the end of the optical / electronic hybrid mounting board, or a monitor optical waveguide connecting two or more optical function elements. It may be optically coupled.

According to a thirty-first aspect of the invention, in the optical / electronic hybrid integrated circuit according to the twenty-fifth aspect, the number of the optical functional elements mounted on the optical / electronic hybrid mounting substrate is two.
It has more monitor ports than the above ports, and
The number of monitor optical waveguides corresponding to the monitor ports is provided on the electronic hybrid mounting board, and the width of at least one of the monitor ports is set to be wider than the signal port width, or these signal ports are The width of at least one of the optical waveguides for signal may be set wider than the width of the signal optical waveguide.

According to a thirty-second aspect of the present invention, an optical functional element having an optical element height reference surface located at a predetermined distance from the active layer, an optical element holding surface for holding the optical functional element, and the optical element holding surface are provided. An optical sub-module comprising a carrier height reference plane at a predetermined distance from the surface and a carrier having carrier electrical wiring, wherein the optical element height reference plane of the optical functional element and the optical element holding of the carrier are provided. The surface is fixed in contact, and the active layer side electrode portion of the optical function element and the carrier electric wiring are electrically connected.

According to a thirty-third aspect of the present invention, in the optical sub-module according to the thirty-second aspect, the carrier is formed of a substrate having irregularities and a dielectric layer formed on the substrate recess, and the optical element holding surface and The carrier height reference plane may be formed by the convex portion of the substrate, and the carrier electric wiring may be formed on the dielectric layer.

According to a thirty-fourth aspect of the present invention, in the optical sub-module according to the thirty-second aspect, the dielectric layer constituting the carrier may be a film material having an electric wiring layer formed on the surface and inside thereof. .

According to a thirty-fifth aspect of the present invention, in the optical sub-module according to the thirty-second aspect, the carrier electric wiring is
It may be formed on the surface and inside of the carrier.

A thirty-sixth aspect of the present invention is an optical / electronic hybrid integrated circuit, comprising an optical waveguide provided on a substrate, the optical waveguide including an under-clad, a core and an over-clad.
A mounting substrate composed of a Si terrace, a dielectric layer, and a conductor pattern provided inside or on the surface of the dielectric layer, wherein the thickness of the dielectric layer is such that the height of the conductor pattern is equal to the optical waveguide overclad surface. An optical element holding surface for holding an optical element, a carrier height reference surface at a predetermined distance from the optical element holding surface, and an optical / electronic hybrid mounting substrate set to have substantially the same height, and A carrier having carrier electrical wiring and an optical functional element held on the optical element holding surface, and the height from the optical functional element active layer to the carrier height reference plane is the optical waveguide core; The optical sub-module, which is set to be approximately equal to the step between the upper surfaces of the Si terraces, and in which the carrier electric wiring and the active layer side electrode of the optical functional element are electrically connected, is the optical / electronic hybrid mounting. substrate The Si terrace and the carrier height reference plane of the optical element submodule are in contact with each other, and the conductor pattern on the dielectric layer surface of the optical / electronic hybrid mounting substrate and the carrier electrical wiring of the optical submodule are electrically connected. The feature is that it is mounted in a connected state.

[0060]

In the hybrid optical integrated substrate of the present invention,
On a conventional Si substrate, a quartz optical waveguide that is an insulator
It is formed with a thickness of 0 μm or more, and high frequency electric wiring is formed thereon. Therefore, regardless of the specific resistance of the Si substrate, the loss due to the influence of the Si substrate, which has a large loss at high frequencies, becomes small, and the Si substrate can be used as an optical / electronic hybrid mounting substrate having a high frequency electric wiring function.

Regarding the high frequency loss due to the Si substrate, the high frequency loss can be further reduced by increasing the resistivity of Si. Specifically, by setting the specific resistance of the Si substrate to an average value of 50 Ω · cm or more, the quartz layer required between the Si substrate and the high frequency wiring layer can be thinned.

Further, if the entire thickness of the silica-based optical waveguide on the Si substrate is large, the substrate is warped, and especially when considering application to an array optical element, an axis shift occurs and good optical element optical characteristics are obtained. Although there was a problem that it could not be a bench, the optical waveguide proposed in the present invention does not impair the high-frequency electrical wiring function and the low-loss optical waveguide function described above in consideration of the influence of the warp of the substrate. To some extent, the thickness of the entire optical waveguide is reduced and optimized. Therefore, the hybrid optical integrated substrate of the present invention has less warp of the substrate and functions as a good optical bench.

Further, in the present invention, when the Si substrate having the convex portion is used, the optical waveguide layer is formed in the concave portion and is used as the base of the high frequency electric wiring, so that the low loss optical waveguide function,
In the high-frequency electric wiring function, the above characteristics are utilized as they are. Then, it can be used as a height reference plane for adjusting the optical axis of the silica-based optical waveguide, and it becomes possible to mount the optical element with high accuracy and drive it by using good high-frequency electrical wiring. It becomes possible to function as an optical bench with higher accuracy.

Further, in the hybrid optical integrated substrate of the present invention, the "optical waveguide substrate with terrace" by the present inventors, in which an optical waveguide is formed in a concave portion on a substrate having irregularities and the convex portion serves as an element mounting portion (see above) : Japanese Patent Laid-Open No. 63-131104 "Hybrid Optical Integrated Circuit") has a basic structure, and in order to exhibit good high-frequency electrical characteristics, an electric wiring layer is formed not on the surface of the convex portion of the substrate but on the concave portion of the substrate. By forming it on the body optical waveguide, the electrical wiring characteristics are less affected by the substrate even when a material having a relatively low resistivity and a high dielectric constant is used as the substrate,
It becomes possible to exhibit excellent high frequency characteristics.

Further, in the hybrid optical integrated substrate of the present invention, in the optical element mounting portion formed on the substrate convex portion, the substrate convex portion directly below the optical element to be mounted is divided into two or more, and the divided convex portion is divided. By forming a dielectric optical waveguide layer in the region between the two, and forming electrode pads and electric wiring for achieving electrical connection with the optical element on the surface of the dielectric optical waveguide, the optical element is formed. When mounting on the optical element mounting part, by mounting so that the divided convex surface of the substrate and the element surface near at least the end of the optical element are in contact with each other, the convex surface of the substrate is The function as a height reference plane for axis adjustment can be exerted. Further, not only the electrode pads directly under the optical element but also all the electric wiring layers on the substrate are formed on the surface of the dielectric optical waveguide layer having a sufficient thickness, so that the high frequency characteristics of the electric wiring layers are remarkably improved. .

As a method of manufacturing the hybrid optical integrated substrate, the etch rate of the dielectric optical waveguide is sufficiently higher than the etching rate for removing the unnecessary portion of the dielectric optical waveguide by etching to form the device mounting portion. It is possible to use a method in which a substrate made of a material having a slow etching rate is used and a dielectric optical waveguide having a value smaller than the dielectric constant of the substrate is used. With this, in the optical element mounting portion, the substrate convex portion serves as an etching stop layer when the optical element mounting portion is formed, so that the substrate convex portion can function as a highly accurate height reference plane. Further, it is expected that the high frequency characteristics of the electric wiring portion will be improved.

Further, in the present invention, when forming the electric wiring layer on the surface of the dielectric optical waveguide layer in the concave portion of the substrate,
By providing a ground conductor layer at the contact interface between the surface of the concave portion of the substrate and the lower surface of the dielectric optical waveguide layer, the structure of the electric wiring layer is formed by forming the signal line layer formed on the surface of the dielectric waveguide and the lower surface of the dielectric body. It is possible to adopt a so-called "microstrip line" structure that is composed of a ground conductor, and it is possible to form an electric wiring excellent in high frequency characteristics at a high density.

In the hybrid optical integrated substrate of the present invention, an optical waveguide made of a dielectric material is formed in a recessed region on a substrate having a recess and a protrusion, and the surface of the protrusion is exposed to locate a positioning reference for mounting an optical element. The structure is made to be a surface, and the electric wiring layer including the electrode pad portion directly below the optical element is formed entirely in the dielectric optical waveguide region of the concave portion of the substrate, so that the low loss optical waveguide function, the optical bench function and the high frequency electric wiring are formed. It is possible to combine the three functions.

In the hybrid optical integrated circuit of the present invention, the optical waveguide for signal and the optical waveguide for monitoring are arranged in the optical waveguide circuit, and the optical functional element is also provided with the monitor port together with the signal port. Therefore, even if it is not easy to monitor the optical coupling rate due to the function of the optical waveguide circuit or the optical functional element, the optical waveguide for monitoring and the monitor port can be used to move the optical waveguide circuit substrate onto the optical waveguide circuit board. The optical functional element hybrid integration can be achieved.

In such a case, for example, the optical waveguide circuit has a function such as wavelength selectivity / optical frequency selectivity, and therefore there is a large restriction on the wavelength / optical frequency of the light propagating through the optical signal waveguide. When adding, when the optical signal waveguide is divided in the middle to mount multiple optical function elements in the middle of the optical waveguide circuit in the middle, or the optical signal port of the optical function element has a switching function. The case where light is not transmitted in the non-energized state is exemplified.

Further, in the hybrid optical integrated circuit of the present invention, the element mounting portion is provided with the height reference plane and the electric wiring plane, and the monitor optical waveguide input end (or output end) is provided.
The height reference plane may be arranged at a position corresponding to, and the electric wiring plane may be arranged at the position of the input end (or output end) of the signal optical waveguide. In this case, further, the height between the height reference plane and the center of the optical waveguide circuit core matches the distance between the active layer (or core center) of the optical functional device mounted on the hybrid optical integrated circuit and the device surface. At the same time, a thin film electrode having a thickness of about 0.5 μm is formed on the surface of the height reference plane. On the electric wiring surface, an electric wiring pattern having a thickness of about 2 to 5 μm and, if necessary, solder bumps are formed. At this time,
The height of the electric wiring surface is set so that the upper surface of the electric wiring pattern (or the solder bump upper surface when a solder bump is formed) is lower than the height reference surface.

Due to such a structure, in the hybrid optical integrated circuit of the present invention, when the optical functional element is mounted on the substrate, active alignment between the optical functional element and the optical waveguide circuit can be performed, and The optical functional element can be fixed using thick film solder such as solder bumps.

That is, the optical functional element having the monitor port and the signal port can be mounted in the optical element mounting portion of the hybrid optical integrated circuit in the upside down form with the active layer (or core) facing downward. When the monitor port upper surface electrode of the optical functional element and the height reference surface of the optical element mounting portion are brought into contact with each other, alignment of the optical functional element and the optical waveguide in the height direction is completed. At this time, a gap is generated between the signal port of the optical function element and the electric wiring pattern on the substrate,
It is not possible to make an electrical connection between the two.

However, since the thin film electrode is formed on the height reference plane, the extraction of the optical functional element monitor port electrode from the height reference plane is realized. Therefore, for the in-plane alignment of the optical functional element and the optical waveguide, active alignment using the monitor port of the optical functional element and the monitor optical waveguide becomes possible. That is, according to the features of the present invention, the optical element can be aligned by active alignment, and the optical element can be fixed using thick film solder.

Further, if a substrate having a slower etching rate than that of the dielectric material forming the optical waveguide circuit is used as the substrate, and if concave portions and convex portions are provided on the surface,
By using the protrusion as a height reference surface corresponding to the monitor port and forming the dielectric optical waveguide in the recess region,
A highly accurate height reference plane can be formed. In particular, if a silicon substrate is used as the substrate, it also functions as a heat sink.

Furthermore, since all the electrical wiring to the signal port in the element mounting portion can be formed on the dielectric layer having a sufficient thickness, it is possible to prevent the influence of the high frequency characteristic deterioration caused by the silicon substrate, and to realize the hybrid optical integrated circuit. The high frequency characteristics can be greatly improved.

Furthermore, by providing one end of the monitor optical waveguide so as to be optically coupled to the optical functional element monitor port and the other end disposed at the end of the optical waveguide circuit board, the waveguide is provided in the middle of the waveguide. It becomes possible to individually mount a plurality of optical functional elements in active alignment.

Further, in this case, if a waveguide connecting the optical functional element monitor port and the end portion of the optical waveguide circuit board as the optical waveguide for monitoring and a waveguide connecting the optical functional element monitor ports to each other are arranged. The number of means that can be applied as an optical coupling efficiency monitoring method in active alignment has increased. Therefore, not only semiconductor elements but also various optical functional elements such as dielectric electro-optical elements, magneto-optical elements, and acousto-optical elements are used as optical functional elements. It becomes possible to mount it.

Further, two or more monitor ports are provided in the optical functional element, and monitor optical waveguides corresponding to the number of the monitor ports are provided in the optical waveguide circuit to serve as these monitor ports or monitor optical waveguides. By arranging those having different widths, it is possible to perform two-stage alignment of coarse adjustment and fine adjustment in active alignment.

In holding the optical element on the carrier, the optical sub-module of the present invention makes the optical element height reference surface provided on the optical element contact and fix the optical element holding surface provided on the carrier and also holds the carrier. A carrier height reference plane is provided by providing a predetermined step from the surface. Therefore, no matter what value is set for the height between the active layer of the optical element and the optical element height reference plane, the heights of the carrier holding surface and the carrier height reference plane correspond to this value. By setting the height difference to an appropriate value, the height difference between the carrier height reference plane and the optical element active layer can be set to a constant value.

In the optical submodule of the present invention, the distance from the carrier reference surface to the active layer can be standardized to a constant value regardless of the type of optical element. Therefore, by using the optical sub-module of the present invention, when manufacturing an optical module in which an optical element and an optical waveguide or an optical fiber are coupled, different types of optical elements can be mounted without changing the dimensions of the optical mounting board, It is expected to have a great effect on mass production of optical modules and improvement of yield. Further, it becomes possible to mount a plurality of various types of optical elements having different sizes on a single mounting substrate, and it becomes possible to manufacture a highly functional hybrid optical integrated circuit.

Further, since the electric wiring is provided on the carrier so that the electrode on the active layer side of the optical element can be taken out, it is possible to easily perform the preliminary inspection of the optical element to be used in manufacturing the optical module and the hybrid optical integrated circuit. effective.

Furthermore, the carrier of the optical submodule is
The high frequency characteristics of the optical submodule can be remarkably improved by forming the substrate having irregularities and the dielectric layer formed in the substrate recess and forming the carrier electric wiring on the dielectric layer. Further, by using a film having an electric wiring layer formed on the surface and inside, that is, a so-called tape carrier, as the dielectric layer, the electric wiring density can be improved. Therefore, an optical element with a large number of electrode terminals, for example 8 × 8
Large-scale monolithic integrated circuit such as optical matrix switch, or OE in which light emitting / receiving elements and electronic circuits are integrated
It is possible to form an optical submodule such as an IC.

If a substrate having electric wiring not only on the surface of the carrier but inside the carrier is used as a carrier of the optical submodule, for example, an alumina multilayer electric wiring board, an optical submodule excellent in high frequency characteristics and electric wiring density can be realized. it can.

In the hybrid optical integrated circuit of the present invention, instead of mounting an optical element in the conventional upside-down form,
The optical submodule is mounted. Therefore, the electric wiring on the optical mounting substrate can be formed on the surface of the optical waveguide over clad layer. As a result, it is possible to easily form the electric wiring, which has been a problem in forming the hybrid optical integrated circuit corresponding to the conventional up-side-down mode. That is, it is possible to avoid the difficulty of forming complicated electric wiring in a narrow area of the optical waveguide substrate.

Further, by using the Si substrate having the unevenness as the substrate, the position of the substrate height reference plane can be determined with high accuracy, and the heat sink function of the Si substrate can be sufficiently exhibited.

According to the optical sub-module and the hybrid optical integrated circuit of the present invention, there are various problems which were conventionally proposed in the hybrid optical integrated circuit in which the optical elements are mounted in the upside-down form, that is, 1) multi-product, The difficulty of mounting a plurality of elements, 2) the difficulty of forming electrical wiring on the substrate in the case of an optical element inserted in the middle of an optical waveguide, and 3) the difficulty of preliminary inspection of the optical element to be mounted can be solved all at once. In addition to this, the optical submodule of the present invention has a carrier structure,
By appropriately selecting the material, excellent characteristics can be obtained in terms of high frequency characteristics and electric wiring density.

[0088]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 9 is a perspective view showing a first embodiment of the hybrid optical integrated circuit of the present invention. Reference numeral 1 denotes a substrate, and in this embodiment, a Si substrate having a surface provided with irregularities was used. Reference numeral 30 denotes a Si terrace that functions as an optical element mounting portion and uses the upper surface of the Si substrate convex portion. Reference numeral 31 is an optical fiber used as the optical waveguide portion of the present embodiment, which is held at an optimum position in the V groove provided in the Si terrace portion 30. Reference numeral 52 is a thin film electrode for making contact with and fixing to the surface electrode of the optical functional element mounted on the Si terrace 30, which has a thickness of 0.5 μ provided on the surface of the Si terrace 30.
A 1 μm thick Au—Sn solder was patterned and formed on the thermal oxide film of m. This thin film electrode 52 is S of the electric wiring portion.
Conductor patterns 51a and 51b for surface electrodes of the optical functional element provided on the surface of the dielectric layer 50 formed in the concave portion of the i substrate 1
Is electrically connected to. Reference numeral 35 is a Si terrace for electronic circuits. The periphery of the terrace 35 is filled with a dielectric layer 50, and the surface thereof has a conductor pattern 51 for an electronic circuit.
Is formed.

In this embodiment, the step difference of the Si recess is set to 80
.mu.m and the thickness of the dielectric layer 50 is 50 .mu.m.
The conductive pattern 51 on 0 was formed by Au plating with a thickness of 5 μm. As a result, a 25 μm step is formed between the upper surface of the Si terrace 35 and the upper surface of the conductor pattern 51.

Reference numeral 37 is an optical functional element, and a semiconductor laser (LD) is used in this embodiment. This element 37 is formed by the Si terrace 30 in an upside down configuration with the active layer facing downward.
By mounting it on the upper element mounting portion, positioning in the height direction between the fiber and the LD can be realized without alignment. The lateral alignment may be performed by monitoring the optical coupling efficiency between the optical fiber and the LD, or may be performed without forming a guide structure by forming the guide structure on the substrate side. At this time, LD3
The electrode on the active layer side of No. 7 contacts the thin film electrode 52 on the Si terrace 30 and is electrically connected to the conductor pattern 51 on the dielectric layer 50. The thin film electrode 52 melts the solder by the temperature rise and
D37 can be fixed on the substrate.

In this embodiment, the Si terrace 3 is used as described above.
Since the LD 37 is fixed by using the thin film electrode 52 on 0,
The Si terrace 30 can be used as a heat sink. At the same time, since the electric wiring except for the connecting portion with the optical functional element is provided on the dielectric layer 50 having a sufficient thickness, it is possible to obtain excellent high frequency characteristics.

Like the LD, the electronic circuit 38 is mounted on the Si terrace 35 with the element formation surface facing down. At this time, since the upper surface of the conductor pattern 51 on the dielectric layer 50 is set to be 25 μm lower than the upper surface of the Si terrace 35 as described above,
If the solder bumps 53 having a thickness of approximately 25 μm are used, the surface of the central portion of the electronic circuit is brought into contact with the upper surface of the Si terrace 35, and at the same time, the electronic circuit electrodes and the dielectric layer 50 are formed without using electric wiring on the Si terrace 35. It becomes possible to connect with the conductor pattern 51. Therefore, in this embodiment, Si
It is possible to dissipate heat from the electronic circuit using the terrace 35, and realize high-frequency electrical wiring without the Si substrate 1.

As described above, according to the optical / electronic hybrid mounting substrate of the present invention, the optical bench function of Si terrace,
That is, the function of aligning the optical axis between the optical functional element and the optical fiber and the function of radiating the optical functional element and the electronic circuit can be exhibited, and at the same time, the high frequency electric wiring function can be exhibited.

(Second Embodiment) FIG. 10 is an overall perspective view for explaining a second embodiment of the optical / electronic hybrid integrated circuit of the present invention. 11 is a sectional view in the vicinity of the optical element mounting portion of the circuit shown in FIG. 10, FIG. 12 is a sectional view taken along the plane AA ′ of the electric wiring portion in FIG. 10, and FIG. 13 is BB ′ in FIG.
FIG.

As shown in FIG. 10, the mounting substrate of this embodiment uses the Si substrate 1 having the surface provided with unevenness as in the first embodiment. In the optical waveguide portion, the silica-based optical waveguide 40 is formed in the concave portion of the Si substrate 1. An optical device Si terrace 30 was provided in the optical device mounting portion as shown in FIG. In the electric wiring portion, a dielectric layer 50 made of polyimide is formed in the concave portion of the Si substrate, and conductor patterns 51 and 510 are provided on the surface and inside thereof. In addition, an electronic circuit Si terrace 35 is installed in the center of the electric wiring portion.

As shown in FIG. 11, in the optical waveguide portion on the left side of the Si terrace 30, there is a step of 17 μm in the Si recess,
A silica optical waveguide 40 including an underclad 41 (thickness: 20 μm), a core 42 (6 μm × 6 μm), and an overclad 43 (thickness: 15 μm) is laminated on this. This waveguide structure is called an "embedded structure". Since the core pattern is embedded in the clad layer having a sufficient thickness, excellent optical waveguide characteristics can be exhibited.

The Si terrace 30 has inclined side surfaces, and the upper surface and the side surface on the electric wiring portion side have a thickness of 1 μm.
thin film electrode 5 formed by patterning Au-Su solder of m
2 are provided. The distance from the surface of the thin film electrode 52 to the center of the optical waveguide core is 5 μm. This dimension is equal to the distance from the element surface of the LD to be mounted to the active layer, and by mounting the optical functional element 37 on the Si terrace 30 in the upside down state with the surface of the active layer facing downward. The alignment of the optical waveguide core 42 and the optical functional element in the height direction can be realized without adjustment.

The electric wiring portion on the right side of the Si terrace is composed of a dielectric layer 50 made of polyimide having a thickness of 15 μm on a recess formed by digging Si to a depth of 25 μm, and a conductor pattern 51 made of an Au pattern having a thickness of 5 μm formed on the surface thereof. And a conductor pattern 510 formed inside. The conductor pattern 51 on the dielectric layer 50 is electrically connected to the thin film electrodes 52 formed on the upper and side surfaces of the Si terrace 35. At this time, the distance between the surface of the Si terrace 35 and the surface of the dielectric layer 50 is about 10
Although there is a step of μm, the height is different 2
It should be emphasized that the fact that the electric wiring between the layers can be realized is an effect of the side surface of the Si terrace 35 having an inclination. If the side surface of the Si terrace 35 is formed substantially vertically, the electric wiring will be broken at the step between the thin film electrode on the Si terrace and the conductor pattern on the dielectric layer. It is difficult to make an electrical connection without using it.

In the electric wiring portion, as shown in FIG. 10, a Si terrace 35 for electronic circuit is provided in the central portion,
An electronic circuit is mounted here. S for optical element
The electric wiring that connects the i-terrace 30 and the electronic-circuit Si terrace 35 is formed by a coplanar wiring including a center conductor 51a and a ground conductor 51b. The electric wiring around the electronic circuit is formed by microstrip wiring composed of the surface conductor pattern 51 and the ground conductor 510 provided inside the dielectric. As shown in FIG. 13, the ground conductor 51b of the coplanar wiring and the ground conductor 510 of the microstrip wiring are connected by the through electrode 520 provided in the dielectric layer.

Comparing the coplanar wiring with the microstrip wiring, the former can be easily formed because it can be formed by one layer of electric wiring, but on the other hand, the wiring density cannot be increased. On the other hand, in the latter, the electric wiring is multi-layered and the manufacturing process thereof is complicated, but a high wiring density can be realized.

In the present embodiment, since the polyimide, which is relatively easy to form the multilayer wiring, is used as the dielectric layer of the electric wiring portion, the microstrip wiring can be formed.
By adopting such a mounting substrate structure, it becomes possible to integrate an electronic circuit having a large number of connection terminals together with an optical functional element.

The optical functional element 37 mounted on this mounting substrate is a semiconductor laser (LD), which is mounted on a sub-carrier 44 which is made of the same heat conductive material as the Si substrate. The subcarrier 44 forms unevenness on the substrate surface,
A conductor pattern is provided on the surface of the concave portion so that the conductor surface is electrically connected to the concave surface.
It is fixed so that the back surface is in contact and the LD back surface and the conductor pattern on the subcarrier are electrically connected. In order to mount the LD mounted on this carrier on the Si terrace 30, the surface of the LD on the active layer side is faced down to S
It was mounted in contact with i-terrace 30. The LD active layer side electrode and the first thin film electrode 53a on the mounting substrate are in direct contact with each other,
The LD back surface electrode is connected to the second thin film electrode 53b on the mounting substrate via the subcarrier. At this time, as described above, the distance between the center of the waveguide core from the surface of the thin film electrode on the Si terrace and the distance between the active layers from the surface of the LD element are made equal to each other. The alignment in the height direction of is completed. The alignment in the in-plane direction was performed by monitoring the coupling efficiency between the optical waveguide and the LD.
The Si terrace serves as a highly accurate height reference plane when the device is mounted, and at the same time functions as a heat sink for the LD.

In mounting the electronic circuit, the element surface is faced down and the solder bumps are used in the same manner as in Example 1 to use Si.
It was mounted on the terrace 35. At this time, as described above, the height of the dielectric layer of the electric wiring portion and the surface of the conductor pattern formed thereon is lower than the upper surface of the Si terrace. As a result of such a structure, the electronic circuit is contacted / mounted on the Si terrace, and all electrodes of the electronic circuit are
It became possible to directly connect to the conductor pattern on the dielectric layer without passing through the electric wiring on the Si terrace. For this reason, it becomes possible to mount an electronic circuit having excellent heat dissipation characteristics and high speed.

As described above, in this embodiment,
An electronic circuit Si terrace 35 was provided in the electric wiring portion, and the height of the conductor pattern surface around the electronic terrace was set lower than that of the Si terrace 35. Therefore, in the optical / electronic hybrid integrated circuit according to the present embodiment, it is possible to directly electrically connect the electronic circuit electrode and the conductor pattern on the dielectric layer by connecting using the solder bump, and at the same time, the electronic circuit Si
It became possible to mount it while maintaining contact with the terrace.
In addition, since the side surface of the Si terrace has an inclination angle, there is a step between the upper surface of the Si terrace and the conductor pattern on the dielectric layer as described above. The thin film electrode provided above and the conductor pattern on the dielectric layer can be electrically connected. For this reason, it is possible to provide the electrode lead-out portion of the optical function element on the Si terrace to enhance the heat sink effect, and to form all the electrical wiring except the electrode lead-out portion on the dielectric layer, which provides excellent high frequency characteristics. I was able to demonstrate it.

According to this embodiment, the optical bench function of the Si terrace, that is, the function of aligning the optical axis between the optical functional element and the optical fiber, the optical functional element, and the heat radiation function of the electronic circuit can be exhibited, and at the same time, The high frequency electric wiring function can be exhibited.

The optical mounting board of this embodiment is, for example,
It can be manufactured by the steps shown in FIGS. 14 (A) to 14 (D).
First, after forming a recess in the Si substrate 1 by a method described in detail later, a silica optical waveguide 40 including an under cladding layer 41, a core pattern 42, and an over cladding layer 43 is formed (see FIG. 14A). Then, the surface of the Si substrate 1 is processed to form the Si terrace 30 for the optical element and the Si terrace 35 for the electronic circuit. At this time, a conductive film 510 such as gold or copper is provided as a ground conductor layer on the bottom surface of the Si recess near the Si terrace 35 for electronic circuit (FIG. 14).
(See (B)). After applying / curing polyimide as a dielectric for the electric wiring portion on this, unnecessary portions of the polyimide are removed by a method such as dry etching to expose the Si terraces 30 and 35. Further, the polyimide layer 50 is etched so that the desired step is lowered from the Si terrace (see FIG. 14C). Finally, the conductor pattern 51 is formed on the surface of the dielectric layer 50, and the conductor pattern 5 on the dielectric layer 50 is formed on the optical device Si terrace 30.
The thin film electrode 52 is formed so as to be electrically connected to 1 (see FIG. 14D).

(Embodiment 3) FIG. 15 is a perspective view showing the structure of a third embodiment of the hybrid optical integrated circuit of the present invention. The major difference between Example 2 and this example is that the dielectric layer of the electric wiring portion was formed using the same material as the optical waveguide.

That is, the Si concave portion is formed with a step difference of 33 μm from the Si terrace surface in both the optical waveguide portion and the electric wiring portion. The under clad 41 (thickness: 35 μm), the core 42 (6 μm) are provided in the Si recess corresponding to the optical waveguide.
m × 6 μm), overclad 43 (thickness: 30 μ
The silica-based optical waveguide 40 having the structure of m) is formed. On the other hand, on the Si recess corresponding to the electric wiring portion, the under clad layer 41 of the silica-based optical waveguide is formed as the dielectric layer 50.
Is formed. The thickness thereof is 25 μm, which is 10 μm lower than the upper surfaces of the optical element Si terrace 10 and the electronic circuit Si terrace 35. As described above, the height of the conductor pattern upper surface of the electric wiring portion is set to be lower than that of the Si terrace upper surface. As a result, all the important electric wiring can be formed on the dielectric layer and connected using solder bumps. At the same time, it became possible to mount the electronic circuit in contact with the Si terrace. Therefore, this mounting board can exhibit high-frequency electrical characteristics and a good element heat dissipation function.

The structure in which the dielectric material of the electric wiring portion and the optical waveguide are formed of the same material as in this embodiment has an effect of simplifying the substrate forming process. Regarding this effect, FIGS. 16A to 16E showing the substrate forming process.
Follow the instructions below. The first step of manufacturing a substrate is a step of forming a step corresponding to a Si terrace on the substrate (see FIG. 16A). In the present embodiment in which Si is used as the substrate, a desired step can be formed by an anisotropic etching method using an alkaline etchant such as KOH.
If the crystal orientation of the Si substrate is properly selected, S
The i-terrace side surface can be formed with an inclination of about 57 °. After that, the under clad layer 41 of a dielectric optical waveguide such as a quartz optical waveguide is formed in the recess of the substrate, and the surface thereof is flattened by a method such as polishing (see FIG. 16B). After that, the core pattern 42 and the over cladding layer 43 of the optical waveguide are formed (see FIG. 16C). After that, the optical waveguide formed in the region to be the electric wiring portion including the Si terrace is removed by etching to expose the Si terrace. At this time, in the etching process of the silica-based optical waveguide and the polymer waveguide (polyimide-based optical waveguide, etc.), for example, in the reactive ion etching using a mixed gas of CF ₄ and H ₂ or O ₂ gas as an etchant, Si is used. It is possible to use the substrate 1 as an etching stop layer. Therefore, when the Si terraces 30 and 35 are exposed as the etching progresses, the etching of the surface does not proceed.

On the other hand, the etching of the optical waveguide portion is continued. As a result, a step between the dielectric surface of the electric wiring portion and the Si terrace can be formed by only one etching step (see FIG. 16D).

Finally, by forming a conductor pattern on the dielectric surface of the electric wiring portion and forming thin film electrodes on the Si terrace surface and the inclined side surfaces, the optical mounting substrate of the present invention can be formed (FIG. 16 (E)). reference). At this time, it is emphasized that the side surface of the Si terrace can be automatically inclined by anisotropic etching of the Si substrate in the step shown in FIG. Since the slope of the side surface of the Si terrace can be easily formed, even if a step is provided between the Si terrace and the upper surface of the dielectric, the electric wiring can be formed between the two without forming a break.

As described above, if the dielectric optical waveguide and the electric wiring portion dielectric layer are made of the same material, as compared with the case where they are made of different materials as in the first embodiment,
The manufacturing process can be simplified.

[0114] In addition, the fact that the side surface of the Si terrace is not vertical but has an inclination as described above also has the effect of significantly relieving the difficulty of manufacturing the mounting substrate. That is, Si
When the side surfaces of the terrace are formed substantially vertically, for example, as shown in FIG.
If a step is formed between the optical element Si terrace 30 and the upper surface of the dielectric layer 50 in the mounting substrate of FIG.
Conductor pattern 51a on the upper thin film electrode 52 and the dielectric layer 50
It becomes difficult to electrically connect and. Therefore,
In order to realize the electric wiring as shown in FIG. 9 by using the Si terraces having highly vertical side surfaces, it is necessary to form the upper surface of the Si terraces and the upper surface of the dielectric without steps in the step of FIG. Since it is necessary to control the etching time and the etching rate of the optical waveguide to be extremely high, it becomes extremely difficult to manufacture a mounting substrate having this structure. This difficulty was solved by providing the side surface of the Si terrace with an inclination as described above.

(Fourth Embodiment) FIG. 17 is a perspective view of a fourth embodiment of the hybrid optical integrated circuit according to the present invention.
FIG. 6 is a sectional view taken along line AA. An under clad layer 60c, a core 60b and an over clad layer 60 are formed on the Si substrate 1.
The embedded optical waveguide 60 in which a is integrated is shown.
In the example shown in FIG. 17, since it is premised that four array optical elements having a pitch of 400 μm are mounted, the core 6
The spacing of 0b is also 400 μm.

On the upper surface of the over cladding layer 60a, as shown in FIG.
As shown in FIG. 8, a coplanar line 61 including a central conductor portion 61a and a ground conductor portion 61b spaced at 400 μm is formed. The width W of the central conductor portion 61a, the gap distance S between the central conductor portion 61a and the ground conductor portion 61b, and the thickness H of the quartz waveguide layer between the coplanar line 61 and the Si substrate 1 are It is a main parameter that affects the high frequency characteristics of the line 61. This parameter will be described later using Tables 1 to 4.

In the mounting portion 63 of the optical element 62, the overclad layer 60a is removed by etching to expose the upper surface of the underclad layer 60c, and the electrical wiring layers 63a, 6a are formed.
3b is formed. In this case, the electric wiring layers 61a, 61
Gold plated wires having a thickness of 5 μm are used as b, 63a and 63b, and the length of the wiring layers 63a and 63b is set to 1 mm or less to reduce the loss.

Center conductor 6 of four coplanar lines 61
1a is connected to a guide post 65a called copper, a block, or a ground post by a gold ribbon wire 64, and the electric wiring layer (electrode) 6 on the underclad 60c described above.
3a, solder pattern 66 made of gold-tin alloy
Is connected to the four electrodes 62c on the lower side of the optical element 62 through.

Similarly, the ground conductor 61b of the coplanar line 61 is connected to the guide post 65b by the gold ribbon wire 64, and the electric wiring layer (electrode) on the underclad 60c.
63b, and is connected to the surface conductive layer 67a of the Si subcarrier 67 through the solder pattern 66. Here, the Si subcarrier 67 has a conductive layer 67 on the surface.
a is formed, and the electrode 62b on the back surface of the optical element 62 is held by being connected to the conductive layer 67a in the recess with gold-tin solder. Therefore, when the optical element 62 is mounted on the mounting portion 63, it is possible to drive the coplanar line 61 at a high frequency together with the four arrays.

When the optical element 62 is mounted on the mounting portion 63, the four active layers 62a of the optical element 62 are optically coupled to the core 60b of the silica-based waveguide on the front side of FIG. In the present embodiment, the electrode 62 of the optical element 62 is
c and the position of the solder pattern 66 are set to the active layer 6 of the optical element
It is provided so as to be shifted laterally from immediately below 2a to prevent the stress associated with fixing the optical element from directly acting on the active layer.

Here, with respect to the above-mentioned main parameters W, S, and H that influence the high-frequency characteristics of the coplanar line,
Consider the axial deviation is S parameter S ₂₁ and the optical bench function.

[0122]

[Table 1]

Table 1 shows the relationship between the coplanar lines w and s and the transmission loss S _{21. A} Si substrate having an average specific resistance of 1 Ω · cm is used. The parameters W and S are several tens of μ, such as for silica optical waveguides.
Since a resist is applied and patterned on a substrate having a step of m, it is difficult to form with good reproducibility in 20 μm or less. Therefore, both w and s are set to 20 μm or more. And in this (Table 1), the thickness hμ of the underclad 2c
m is 24 μm, the total thickness of the quartz waveguide is H μm is 60 μm
As a result of changing w from Examples I-1 to I-5,
When w and s are minimum, the S parameter S ₂₁ is minimum and the loss is minimum. In addition, in this (Table 1), since the numerical values of the thickness h and H are not changed, the axis deviation is constant at 0.7 μm even with four arrays.

[0124]

[Table 2]

(Table 2) uses the results of (Table 1) to obtain S ₂₁
Is set to (w, s) = (20, 20) μm that minimizes, and the S parameter and the axis deviation when the thickness h of the underclad 60c is changed and H is changed are picked up. Examples II-1 and II-7 are examples in which the conventional structure is applied, and Examples II-2 to II-6.
In this example, h and H are changed. As a result,
A favorable value is shown when H is around 50 to 90. The axis shift is caused by the warp of the substrate due to the thickness of the clad thickness in the array structure, which leads to an increase in coupling loss.

More specifically, referring to (Table 2), with respect to the thickness H dependency, the loss of high-frequency electrical wiring is 1.0
It should be less than or equal to dB / cm, and when considering the wide range of applications of the hybrid substrate of the present embodiment, it is 1.5 dB / cm.
It is considered necessary to be the following. From (Table 2), it is necessary that the total thickness H of the quartz layer is 50 μm or more for the loss to be 1.5 dB / cm or less.

Further, in order for the hybrid substrate to maintain a good optical bench function, it is necessary that the substrate warp is small.
In FIG. 18, since the quartz optical waveguide layer and the Si substrate 1 have different thermal expansion coefficients, the warpage of the substrate increases as H increases. If the warp of the substrate becomes large, the end face of the optical waveguide and the optical element, for example, the active layer of the LD array are misaligned to cause optical coupling loss, which impairs the optical bench function. Since the optical / electric hybrid mounting substrate is required to be developed into a 4 × 4 switch or the like, it is necessary to be able to deal with arraying of optical elements, for example, by mounting a 4-array LD module or the like on this substrate.
As a result, it is necessary to reduce the numerical value (axis deviation) in the right column of (Table 2). FIG. 19 shows the thickness H of the quartz layer on the Si substrate.
And the warp (curvature radius) of the Si substrate and the axis shift in the 400 μm-spaced 4-array LD module.
From this FIG. 19, it is found that the thickness H is 120 μm or less in order to suppress the axis deviation to 1 μm or less.

In summary, in the silica optical waveguide shown in FIG. 18, H must be 50 μm or more and 120 μm or less in order to satisfy the high frequency electric wiring function and the optical bench function for mounting the optical element. I understood.

As can be seen from (Table 1) and (Table 2), an underclad h = 30 μm and a core diameter of 6 which are considered to be suitable and suitable as a low-loss optical waveguide are considered.
× 6 μm, overclad = 30 μm, all-quartz layer 66
FIG. 17 shows an example using a hybrid optical integrated substrate of μm. The propagation loss of the optical waveguide shown in FIG. 17 is 0.1 dB / cm or less, and when LDs are used as optical elements, all four arrays have good characteristics even at high speed modulation at 10 GHz.

In this way, the present embodiment has a low loss optical waveguide function, an optical bench function with little axis deviation, and a high frequency electrical wiring function with less S ₂₁ .

FIGS. 20 and 21 show the four arrays of FIG. 17 divided into a single unit. In this case, since the array element is not an array element but a single element, the axis deviation does not occur even if the substrate warps.
Therefore, even if the condition that the thickness H is 120 μm or less is excluded, the above-mentioned three functions are provided. On the other hand, when the single body has an array structure, the condition that the thickness H is 120 μm or less is added.

In the present embodiment, the coplanar line 61
Was formed on the surface of the over-cladding, but the position of the coplanar line can be formed at other positions. FIG.
17 is a side view of FIG. 23, FIG. 23 is a side view of a thin overclad layer 60a under the coplanar line 61, and FIG.
The side view of what formed the coplanar line 61 directly on the under clad 60c is shown. Even if the height of the coplanar wiring layer is set lower than the upper surface of the upper clad of the optical waveguide portion as in the examples shown in FIGS. 23 and 24, the same electrical / optical mounting substrate can be used.

(Fifth Embodiment) FIG. 25 is a diagram showing a fifth embodiment of the hybrid optical integrated circuit of the present invention, and FIG.
FIG. 26 is a sectional view taken along line D-D in FIG. 25. The above-mentioned Example 4 is
This is an example using a general Si substrate (resistivity ˜1 Ω · cm). On the other hand, the high frequency electric wiring function can be further improved by increasing the specific resistance of the Si substrate. As a result, the silica-based optical waveguide between the coplanar line and the Si substrate can be thinned, and the high-frequency line can be placed on the thinner underclad 2c as shown in FIG. Can be expanded.

First, regarding the structural parameters of the substrate used in FIG. 25, the structure having the same structure as the cross-sectional view of the high frequency electric wiring portion DD in FIG. To convert. In FIGS. 25 and 26, 61a is a central conductor portion of the coplanar line, 61b is a ground conductor portion, 60c is a lower clad layer, and 1 is Si having a higher resistance than that of the first embodiment shown in FIG.
The substrate. Further, in FIG. 25, 67 is a subcarrier of Si, and the optical element 62 is held in the concave portion. A conductive layer 67a is formed on the front surface of the subcarrier 67 and is electrically connected to the back surface of the optical element 62. By connecting both legs of this subcarrier to the solder pattern 67b, the coplanar line 61 and the electrode 62b on the back surface of the optical element 62 are electrically connected. On the other hand, the electrode 62c beside the active layer of the optical element is electrically connected by the solder pattern 67b formed on the central conductor portion 61a of the coplanar line 61, and the optical element 62 can be driven by this coplanar line. Furthermore, this Si subcarrier 67
Absorbs the heat generated by the optical element and radiates it to the air or the coplanar line 61. In this embodiment, the solder pattern 67 connected to the electrode 62c of the optical element 62 is used.
The position of b is provided so as to be shifted laterally from directly below the active layer 62a of the optical element, and the stress associated with fixing the optical element is prevented from directly acting on the active layer.

The main parameters that affect the high frequency characteristics of this coplanar line are the thickness h of the quartz underclad layer between the coplanar line and the Si substrate, the width w of the center conductor 61a of the coplanar line, and the center conductor. It is a gap interval s between 61a and the ground conductor layer 61b of the coplanar line.

The relationship between these parameters S and W and the S parameter S ₂₁ representing the loss of the coplanar line is shown in (Table 3), and S depending on the thickness of the underclad 2c is based on s and w according to this (Table 3). The relationship between the parameter S ₂₁ and the axis deviation is shown in (Table 4).

The Si substrate has an average specific resistance of about 50
Ω · cm is used. As for w and s, 20 μ is used because the resist is applied and patterned on a substrate having a step of several tens μm such as a quartz optical waveguide.
When it was less than m, it was difficult to form with good reproducibility. Therefore, both w and s are set to 20 μm or more. 25 and 26 show an example of the optical element alone, Table 4 shows the axis deviation caused by the warp of the substrate when the optical elements of 4 arrays are mounted at a pitch of 400 μm.

First, (Table 3) shows changes in the S parameter S ₂₁ depending on the conductor width w and the gap s which are the structural parameters of the coplanar line.

[0139]

[Table 3]

As can be seen in Table 3, Example II
As a result of I-1 to III-5, similar to (Table 1) (w, s)
= (20,20) μm, and the loss is the smallest.

[0141]

[Table 4]

Further, as shown in (Table 4), (w,
Assuming that s) = (20,20) μm, S ₂₁ and axis deviation due to changes in the underclad thickness h are displayed. Thus, in order to set S ₂₁ at 10 GHz to 1.5 dB / cm or less, h must be 20 μm or more. Since the specific resistance of the Si substrate was increased in this way, the thickness of the quartz layer on the Si substrate could be made thinner than in Example 4.
Further, in order to make the axis shift between the active layer of the optical element and the core of the optical waveguide 1 μm or less, the total thickness H of the quartz layer is 120 μm
It must be m or less.

To summarize the above, in the silica-based waveguides of FIGS. 25 and 26, in order to satisfy the high-frequency electrical wiring function and the high-precision optical bench function for mounting an optical element, the silica-based optical waveguide underclad thickness is required. It was found that h must be 20 μm or more. 400 μm
When four or more optical elements are mounted at a pitch, the condition that the total thickness H of the silica-based optical waveguide is 120 μm or less is added.

As can be seen from (Table 3) and (Table 4), underclad h = 30 μ, which is considered to be the most suitable and optimal as a low-loss silica optical waveguide.
m, core diameter 6 × 6 μm, overclad thickness 30 μm,
FIG. 25 shows an example in which a single LD module is used as an optical element using a substrate having a total quartz layer of 66 μm.

As described above, the hybrid optical integrated substrate of the fifth embodiment has not only the proven low loss optical waveguide function,
It satisfies the high-frequency line wiring function for driving optical elements and the high-precision optical bench function for ensuring the flatness of the substrate. Further, as compared with Example 1, an underclad having a thickness of 30 μm, which has a sufficient track record as an optical waveguide, is used, and a guide post or the like is not used, so that the electrode structure can be simplified. Therefore, the high frequency characteristics are improved, and the mounting work is simplified.

The propagation loss of the optical waveguide of this hybrid optical integrated circuit was 0.1 dB / cm or less. Further, when the LD is used as the optical element, good characteristics are exhibited even at high speed modulation at 10 GHz.

(Embodiment 6) FIG. 27 is a diagram showing a sixth embodiment of the hybrid optical integrated circuit of the present invention. Instead of the flat Si substrate 1 used in Example 4, Si having irregularities is used.
The substrate is used. The under clad layer 60c of the silica-based optical waveguide is formed in the recess of the Si substrate 1,
The convex portions 68a and 68b of the Si substrate are exposed to the optical element mounting portion 68 as shown in the figure and can be used as a height reference surface when mounting the optical element 62.

FIG. 26 is a sectional view taken along line BB in FIG.
The under clad layer 60c having the same structure as the above and having the thickness h = 30 μm optimized in (Table 3 and Table 4) is also used here. 2 is a sectional view of the optical element mounting portion 68 taken along the line CC.
8 shows. Thus, the thin electrode 62c is formed on the convex portion 68a of the Si substrate 1 so as to avoid the active layer 62a of the optical element 62, and serves as the height reference plane of the optical element 62 and the electrode portion. The coplanar line uses a gold plating layer having a thickness of 5 μm on the underclad, but uses a gold sputtered film having a thickness of 1 μm or less on the Si terraces 68a and 68b. The electrode 62b on the back surface of the optical element 62 is held by the Si subcarrier 67, and electrically passes through the conductive layer 67a and the conductive adhesive 69 on the surface of the Si subcarrier 67 to the electrode portion 61b on the Si terrace 68b. There is continuity.

By using the Si substrate having the convex portion in this manner, the Si convex portion 68a can be used as a mounting height reference surface, and the optical element 62 and the optical waveguide core 62a can be aligned with higher accuracy. be able to. Further, the heat generated by the optical element 62 passes through the sub-carrier 67 and 68b.
The heat can be dissipated to the Si substrate 1 having good thermal conductivity via 1 and the 1 is closely attached to the package 70 having good thermal conductivity.
The heat dissipation of the optical element 62 is greatly improved.

The high frequency characteristics of the coplanar line portion 14 are also good as in the fourth embodiment. Si terrace 68
The high-frequency line is located immediately above the Si substrate in the electrodes on a and 68b, but the distance through which the high-frequency actually flows is very short and its loss is very small.

Further, the total thickness H of the under clads 60c, 60b and the over clad 60a is 66 μm optimized in Table 4, and it goes without saying that it is a good optical bench with a small warp.

(Embodiment 7) FIG. 29 is a perspective view showing a seventh embodiment of the hybrid optical integrated circuit of the present invention.

The present embodiment is characterized in that an LD 71 is used as the optical element 62 of the sixth embodiment, and an LD driver 72 for driving it is mounted on the same substrate 1. The optical element mounting portion 68 has exactly the same structure as in FIG. The coplanar line portion 61b on the input side to the LD driver has exactly the same structure as the coplanar line portion 61 of FIG. However, the coplanar line portion 61a connecting the LD driver 72 and the LD 71 is 4 in order to achieve impedance matching between the coplanar line of the 50Ω system and the LD.
A high frequency chip resistor 73 of 0Ω is inserted. A cross-sectional view of the EE having the LD driver 72 is shown in FIG. In order to efficiently dissipate the heat of the LD driver 72, which generates a large amount of heat as described above, the LD driver 72 is placed on the convex portion 74 of the Si substrate. Further, as in the fifth embodiment, the heat of the LD portion is efficiently absorbed by the Si substrate. The Si substrate 1 can efficiently radiate heat by bringing the entire LD module into close contact with a package made of a material having good thermal conductivity. The LD driver 72 and the coplanar wire 61a and the LD driver 72 and the DC bias line 61c are connected using the guide post 65c and the gold ribbon wire 64 as shown in FIG. It can be kept to a minimum. This Si convex portion 74
Touches only the bottom surface of the driver and is away from the coplanar line, so that the high frequency characteristics are not impaired.

The propagation loss of the optical waveguide of this hybrid optical integrated circuit was 0.1 dB / cm or less. Also, LD
10G from the coplanar line input end 75 to the driver 72
By inputting the modulation signal of Hz, and further adjusting the amplitude and the modulation potential by the DC bias line of 61c,
The LD element showed good modulation characteristics up to 10 GHz. In this way, if the hybrid optical integrated substrate of the seventh embodiment takes advantage of the low loss optical waveguide function, the high frequency electric wiring function, and the high precision optical bench function, the high speed LD as described above is obtained.
The module can be realized on the same substrate of several cm square.

(Embodiment 8) FIG. 31 is a perspective view showing an eighth embodiment of the hybrid optical integrated circuit of the present invention.

This embodiment has the same structure as that of the seventh embodiment with respect to the silica type optical waveguide portion, the optical element mounting portion 13, the coplanar wiring portions 61a and 61b, and the LD driver mounting portion 61c.

However, the Si substrate 1 is extended and the guide groove 77 is formed so that the fiber 76 can be connected to the end face 62d of the silica-based optical waveguide without alignment. This guide groove X
A cross-sectional view of the section -X is shown in FIG. Such a guide groove 7
7 can be easily formed by etching the optical waveguide and the Si substrate. The guide groove 77 facilitates the alignment of the optical fiber 76 without the need for alignment.
It is possible to connect to b, and the application of this hybrid optical integrated mounting substrate can be further expanded.

(Ninth Embodiment) FIG. 33 is a perspective view showing a ninth embodiment of the hybrid optical integrated circuit of the present invention.

This embodiment has the same structure as in Embodiment 4 except for the silica-based optical waveguide portion, and the silica-based optical waveguide portion is changed from the buried type to the ridge type. Along with this, only the thickness of the overclad 62a is the same as that of the ridge type optical waveguide 78, so that it is thin. As described above, the characteristics of the ridge type optical waveguide are slightly inferior to those of the embedded type, but in other respects, it functions as a good hybrid optical integrated mounting substrate.

(Embodiment 10) The structure other than the optical element mounting portion 3 is the same as that of the embodiment 4 shown in FIG.
The tenth embodiment (not shown) is obtained by replacing the third embodiment with the optical element mounting portion 68 using the Si terrace as shown in FIG. Compared with the fourth embodiment, good characteristics are maintained as in the fourth embodiment in terms of the optical waveguide function and the electrical wiring function, and in addition, as described in the sixth embodiment, the Si terrace has a high optical element mounting capability. It has the advantage that it can be used as a reference surface and is excellent in heat dissipation.

(Embodiment 11) FIG. 34 is a perspective view showing an eleventh embodiment of a hybrid optical integrated circuit of the present invention.

In this embodiment, the silica-based optical waveguide parts 60a and 6 are used.
The structure other than 0b is the same as that of the fifth embodiment shown in FIG.
The embedded optical waveguides 60a and 60b are replaced by 78a and 78
This is a ridge type optical waveguide of b and 78c. As described above, the ridge-type optical waveguide has an optical waveguide characteristic slightly inferior to that of the embedded-type optical waveguide.
Other than that, in the high frequency electric wiring function and the optical bench function, it functions as a good mounting board for hybrid integration as in the fifth embodiment.

(Embodiment 12) FIG. 35 is a perspective view showing a twelfth embodiment of the hybrid optical integrated circuit of the present invention.

In this embodiment, the silica-based optical waveguide parts 60a, 6 are used.
Structures other than 0b are the same as in Example 6 shown in FIG. 27,
The buried type optical waveguides 60a and 60b in FIG. 27 are replaced with ridge type optical waveguides 78a, 78b and 78c. As already mentioned, the ridge type optical waveguide
Although the optical waveguide characteristic is slightly inferior to that of the embedded optical waveguide, the present Example 12 has a high frequency electric wiring function other than that.
In the optical bench function, it functions as a good hybrid optical integrated mounting substrate as in the sixth embodiment.

As described above, according to the present embodiment, it is possible to provide a hybrid optical integrated mounting board having the three functions of the low loss optical waveguide function, the high frequency electric wiring function and the high precision optical bench function at the same time.

(Embodiment 13) FIG. 36 is a sectional view showing a thirteenth embodiment of the optical / electronic hybrid optical integrated circuit of the present invention. 1 is a Si substrate having a specific resistance of 100 Ωcm.
In the optical waveguide portion, the silica-based optical waveguide 2 is formed in the concave portion provided on the surface of the substrate, and the thickness of each layer is 30 μm under clad, 6 μm core, and 30 μm over clad.
m. A dielectric layer 50 made of the same material as the silica-based optical waveguide under-cladding layer is formed in the Si recess of the electric wiring portion. The thickness of the dielectric layer 50 between the optical device Si terrace and the electronic circuit terrace 35 is 20 μm,
A conductor pattern 51 having a thickness of 5 μm is formed on this. A thin film electrode 52 is formed on the upper surface and the inclined side surface of the optical element Si terrace 30 and is electrically connected to the conductor pattern 51. The optical function element 37 is the thin film electrode 52.
It is mounted on the Si terrace 30 in an upside-down state while maintaining electrical connection with. The electronic circuit 38 is mounted on the Si terrace 35 with the element surface facing downward, and the conductor pattern 51 is formed by the solder bumps 53 having a height of 5 μm.
Fixed with the connection. In the electric wiring part on the right side of the electronic circuit, the second dielectric layer 5 (made of polyimide) is formed on the dielectric layer 50 made of the silica-based optical waveguide under-cladding layer.
20 are stacked. A multilayer conductor pattern 510 is provided inside the second dielectric layer 520, and a conductor pattern 51b is provided on the surface thereof.

In this embodiment, the dielectric layer of the electric wiring portion is a dielectric layer 50 made of the same material as the silica-based optical waveguide, and a second dielectric layer 520 made of polyimide is provided on a part of the dielectric layer 50. A multilayer electric wiring 510 was provided inside. As a result of such a structure, it is possible to connect optical elements with low wiring density and electronic circuits with high-speed coplanar wiring, and use multi-layer myurostrip wiring for wiring with high wiring density. It was

Further, in this embodiment, the coplanar wiring region,
Both the microstrip wiring region and the undercladding layer of the optical waveguide of the first dielectric layer are used. As a result, there is also an effect that the manufacturing process of the mounting substrate can be simplified as compared with the second embodiment for achieving the same purpose as the present embodiment.

(Embodiment 14) FIG. 37 is a sectional view showing a fourteenth embodiment of the hybrid optical integrated circuit of the present invention. The substrate 1 in this embodiment is a ceramic substrate,
On top of this, Si terrace 30 for optical element and Si for electronic circuit
Terrace 35 is provided. The optical waveguide 40 is a silica optical waveguide. The dielectric layer 50 of the electric wiring portion is made of polyimide. The feature of the present embodiment is that not only the conductor pattern 51 is provided on the surface and inside of the dielectric layer 50 of the electric wiring portion, but also the electric wiring 5 is provided inside the ceramic substrate 1.
30 is provided.

In this example, a Si terrace having excellent thermal conductivity was used for the element mounting portion, a quartz optical waveguide was used as the optical waveguide, and the electric wiring portion was formed inside and on the surface of the dielectric layer provided on the substrate. In addition to providing the conductor pattern, the conductor pattern was also provided inside the ceramic substrate where it is easy to provide the multilayer electric wiring. As a result, the mounting board of this embodiment has three functions of a high performance optical waveguide function, a Si optical bench function, and a high frequency electric wiring function, and it is possible to form an extremely high density electric wiring.

As in this example, to provide Si terraces on a substrate made of a different material such as ceramic,
For example, the method of anodic bonding can be used. This is because the ceramic substrate surface and Si
This is a method in which a thin SiO ₂ film is formed on the back surface of the terrace, and the both are pressed and heated to bond them.

(Fifteenth Embodiment) FIG. 38 is a perspective view showing an optical mounting board in a fifteenth embodiment of the hybrid optical integrated circuit of the present invention. In the figure, reference numeral 1 is a Si substrate, and an uneven structure is formed on the surface of this substrate. The optical waveguide portion I is formed on the concave portion of the Si substrate, 60C is a silica-based optical waveguide undercladding layer (thickness 50 μm), and 60b is a silica-based optical waveguide core portion (6 × 6 μm). It is embedded in the over cladding layer 60a having a thickness of 30 μm. In the optical element mounting portion II, the convex portion of the Si substrate is exposed, and this becomes the height reference plane 30 when the optical element is mounted.
The height reference plane 30 is divided into two parts centering on a position corresponding to the waveguide core 60b, and the periphery thereof is filled with a silica-based optical waveguide lower cladding layer 60c. The thickness of the under cladding layer 60c in the optical element mounting portion II is 3
An electric wiring layer 500 of a coplanar structure composed of a central conductor pattern 50 and a ground conductor pattern 51 is formed on the surface thereof, and one end of the central conductor pattern, that is, a height divided into two. A solder pattern 52 is formed in the gap portion of the reference surface 30. The thickness of the under clad layer 60c of the silica-based optical waveguide is 35 μm.
m is a thickness sufficient for the electric wiring formed on the surface thereof to exhibit excellent high frequency characteristics without being affected by the Si substrate. Here, the electric wiring layer 500 and the solder pattern 52
Both have a thickness of 5 μm. In this embodiment, the electric wiring layer 500 is made of gold, and the solder pattern 52 is made of gold-tin alloy.

FIG. 39 shows a state in which a semiconductor optical device is mounted on the hybrid optical integrated substrate of FIG. 38, with a cross section taken along line AA 'of FIG. In this embodiment, the height reference plane 30 composed of Si convex portions is divided into two, and the gap is divided into the under cladding layer 6 of the silica optical waveguide.
Since the central conductor 50 and the solder pattern 501 as electric wiring are formed on the surface of the semiconductor optical element 4 by being filled with 0c, when mounting the semiconductor optical element 4, including the connection portion with the electrode pad 37a of the semiconductor optical element, Under-cladding layer 6 of silica optical waveguide with sufficient thickness for all electrical wiring layers
It became possible to form on the surface of 0c. For this reason, the influence of the low resistivity and high dielectric constant of the Si substrate on the electrical wiring can be ignored. Since the silica-based optical waveguide layer is superior to the Si substrate as an electric wiring substrate in terms of resistivity and dielectric constant, the electric wiring of this embodiment can realize excellent high frequency characteristics.

Further, the height from the convex surface 30 as the height reference plane of the Si substrate 1 to the center of the optical waveguide core 60b is set equal to the height from the active layer 37b of the semiconductor optical device 37 to the device surface. . Therefore, the optical semiconductor element 37
In mounting the semiconductor device, the semiconductor device is mounted on the height reference plane 30 of the convex portion of the Si substrate 1 in the upside-down state, and the height of the silica-based optical waveguide core portion 60b and the active layer 37b of the semiconductor optical device are It has become possible to match the heights of. At the same time, the convex portion of the Si substrate 1 also functions as a heat sink for the semiconductor optical device. The above-mentioned optical element mounting portion is formed by removing unnecessary portions of the silica-based optical waveguide layer by etching. At this time, the Si substrate functions as an etching stop layer. Therefore, it should be emphasized that the height of the positioning height reference plane 30 can be determined extremely accurately.

The propagation loss of the optical waveguide of this hybrid optical integrated circuit was 0.1 dB / cm or less. Further, the positioning accuracy of the semiconductor optical device and the silica-based optical waveguide was about 1 μm, and the semiconductor optical device showed good characteristics even at high speed modulation at 10 GHz.

As described above, this embodiment has three functions of the low loss optical waveguide function, the optical bench function and the high frequency electric wiring function.

(Embodiment 16) FIG. 40 is a perspective view showing an optical mounting board in a 16th embodiment of the hybrid optical integrated circuit of the present invention. This embodiment is different from the fifteenth embodiment in that the optical element mounting portion II is provided with a guide 79 for positioning the in-plane direction of the semiconductor optical element, and other configurations are the same as the fifteenth embodiment. In this embodiment, the guide 79
Is formed of the same material as the optical waveguide 60, that is, quartz glass.

FIG. 41 shows a state in which the semiconductor optical device 37 is mounted on the substrate 1 of FIG. 40, with a cross section taken along line BB 'of FIG. Guide 79 provided on the substrate 1
Has a height of 5 μm, and correspondingly, the semiconductor optical element 37 is provided with a positioning groove 80 having a depth of 6 μm. Therefore, with the semiconductor optical device 37 in the upside-down state, the positioning groove 80 and the guide 79 on the substrate 1 are brought into contact with each other, and the upper surface of the optical device is brought into contact with the Si convex portion surface 30 to be mounted on the device mounting portion. Just by mounting it, the alignment between the optical waveguide and the optical semiconductor element could be completed without any alignment work.

(Embodiment 17) FIG. 42 is a perspective view showing an optical mounting board in a seventeenth embodiment of the hybrid optical integrated circuit of the present invention. The difference between the present embodiment and the fifteenth and sixteenth embodiments is that the optical element 37 held by the subcarrier 67 is mounted on the optical element mounting portion II, and other constituent elements are basically implemented. Similar to Example 1 or 2.

In FIG. 42, a solder pattern 52 for the optical element active layer is formed on the central conductor pattern 50 of the electric wiring layer 500 of the optical element mounting portion II, and a solder pattern for the subcarrier is formed on the ground conductor pattern 51. 53 is formed. FIG. 43 shows a state in which the optical element held by the subcarrier 67 is mounted on the substrate 1. FIG. 43 is a sectional view taken along line CC ′ of FIG. 42. In FIG. 43, the subcarrier 67 is made of the same material as the Si substrate 1, and the optical element 37 is held in the recess 67a.
A conductive layer is formed on the surface of the recess 67a so as to be electrically connected to the back surface of the optical element 37. The convex surface 6b of the subcarrier 67 is the surface of the optical element 37 (see FIG.
The lower surface of the optical element 37 is flush with the lower surface of the optical element 37 or is lower than the height of the surface of the optical element 37.

Therefore, when the subcarrier 67 is mounted on the element mounting portion of the hybrid optical integrated substrate, the surface of the optical element 37 and the Si convex portion 30 are brought into contact with each other to complete the height adjustment. The electrode 37a on the active layer 37b side of the optical element 37 is electrically connected to the central conductor pattern 50 on the substrate via the solder pattern 52.

In this embodiment, the optical element 37
The positions of the electrode 37a and the solder pattern 52 are shifted laterally from directly below the optical element active layer 37b. This is to prevent the stress associated with fixing the optical element from directly acting on the active layer. Also, an electrode (not shown) on the back side of the optical element
Passes through the conductive layer 60 formed on the surface of the recess 67a of the subcarrier 67 and is connected to the ground conductor pattern 51 on the substrate via the solder pattern 53. Further, the surface of the subcarrier 67 and the Si convex portion 30 are thermally connected via the heat conductive material 81, and the mounting of the optical element 37 on the substrate is completed.

Since the present embodiment has the above-mentioned structure, the optical device back surface side electrode can be taken out from the same surface as the active layer side electrode through the subcarrier 67, so that the optical device surface mounting can be performed wirelessly. . Therefore, by combining with the substrate structure of the present invention, excellent high frequency characteristics can be exhibited. Further, as a heat sink of the optical element, a path for directly radiating heat from the surface of the optical element to the convex portion of the Si substrate 1 and a path for radiating heat to the convex portion of the Si substrate 1 through the subcarrier from the rear surface of the optical element are formed. From the viewpoint of, it also exhibits excellent activity.

(Embodiment 18) FIG. 44 (A) and FIG.
(B) is a diagram showing an eighteenth embodiment of the optical / electronic hybrid integrated circuit of the present invention, FIG. 44 (A) is a perspective view, and FIG. 44 (B) is in FIG. 44 (A). It is sectional drawing which follows the BB 'line. This example is different from Example 17 in that
Sub-carrier 67 holding the optical functional element and Si terrace 3
It is in the structure of the connection part with 0. That is, the optical functional element 37
The active-layer-side surface electrode 37a of the above is connected to the conductor pattern 51a provided on the dielectric layer 50 and the solder bump 53 which is a conductive bonding material.
The connection is fixed via a. On the other hand, the electrode on the back side of the element passes through the conductor pattern on the surface of the subcarrier 67, and the Si terrace 3
The thin film electrode 52 provided on the electrode 0 and the solder bump 53b provided on the electrode 52 are connected and fixed.

In the seventeenth embodiment, the subcarrier 67 is S
When fixing to the i-terrace 30, the conductor pattern 51 to which the subcarrier 67 is connected was provided on the dielectric layer 60c. For this reason, it is necessary to apply a heat conductive material between the sub-carrier 67 and the Si terrace 30 in order to enhance the heat radiation effect of the device, resulting in a problem that the mounting process of the optical device becomes complicated. . On the other hand, in this embodiment, since the sub-carrier 67 is fixed on the Si terrace 30 via the solder bump 53b, the solder bump 53
b can also serve as a heat conductive material. Therefore, there is an advantage that the mounting process can be simplified.

(Example 19) FIGS. 45 (A) and 45
(B) is a diagram showing a nineteenth embodiment of the optical / electronic hybrid integrated circuit of the present invention, FIG. 45 (A) is a perspective view, and FIG. 45 (B) is in FIG. 45 (A). It is sectional drawing which follows the BB 'line. This embodiment is different from the eighteenth embodiment in that the mounting substrate 1 is provided with a guide for in-plane positioning of the optical functional element 37, and in the subcarrier holding the optical functional element, from the outer surface 67c of the subcarrier 67. The distance to the active layer 37b is determined by the guide inner wall 60d on the mounting substrate 1.
Is set to be equal to the distance D from to the center of the optical waveguide core. By doing so, it is possible to perform optical element hybrid integration without using alignment while using subcarriers.

To set the distance from the outer surface 67c of the subcarrier 67 to the active layer 37b of the optical functional element 37 to a desired value D, for example, the optical functional element is set as the subcarrier as shown in FIG. Just fix it. That is, 90
Reference numeral a denotes an element fixing jig, and a guide 90b for setting a subcarrier at a desired position and a marker 91 for setting an optical functional element at a desired position are provided on this surface. Therefore, first, the marker 41 formed on the surface of the optical element 37 on the active layer side is aligned with the marker 91 on the jig 90a with the surface of the active layer side facing downward so that the optical element 37 is placed on the jig 90a. After mounting, the optical functional element 37 may be fixed to the subcarrier 67 with the outer side surface 67c of the subcarrier abutting against the guide 90b on the jig 90a.

In the element mounting method in which the positioning reference surface provided on the optical element and the guide surface on the mounting substrate are directly abutted, a lattice defect may occur in the optical element when the side surface of the optical element and the guide surface are in contact with each other. There was a problem from the viewpoint of the reliability of the optical element. On the other hand, in this embodiment, since the outer side surface 67c of the subcarrier 67 is mounted by abutting against the positioning guide 90b, the alignment-free element is mounted without contacting the side surface of the optical functional element with the guide. Can be realized. For this reason, even in mounting an element using the guide structure, it becomes possible to mount the element without lowering the reliability of the element.

(Embodiment 20) FIG. 47 is a perspective view showing an optical mounting board in a twentieth embodiment of the hybrid optical integrated circuit of the present invention. The feature of this embodiment is that the optical element mounting portion
In II, the recess of the Si substrate 1 and the under cladding layer 6
0c and a structure in which the ground conductor layer 51a is buried between them and 0c, and the other constituent elements are almost the same as those in the 15th to 17th embodiments. As a result of such a structure, in the optical element mounting portion II, the underclad layer 60c, the electric wiring 50 provided on the surface thereof, and the embedded ground conductor 51a.
And form a microstrip line, and excellent high frequency characteristics can be obtained. By using the microstrip line, it becomes easier to increase the electric wiring density as compared with the coplanar line as in Examples 15 to 17.

FIG. 48 is a sectional view taken along the line DD ′ of FIG. 47, showing a state where the LD array 37 is mounted on the hybrid optical integrated substrate shown in FIG. The electric wiring portion 500 is formed in the concave portion of the Si substrate 1 including the electrode connecting portion with the optical element. Further, the surface of the convex portion of the Si substrate 1 serves as a height reference plane of the LD array 4 and also functions as a heat sink.

As described above, also in this embodiment, it is possible to simultaneously exhibit the three functions of the low loss function, the high frequency electric wiring function and the optical bench function.

(Embodiment 21) FIG. 49 is a perspective view showing an optical mounting board in a twenty-first embodiment of the hybrid optical integrated circuit of the present invention, showing an example of the structure in the case where the length of the optical element is long. Shows. The optical element 37 is a 15 mm long Li
It is a NbO ₃ (LN) waveguide. In this embodiment, as in the other embodiments, a silica optical waveguide on a Si substrate is used. When the optical element length becomes long as in this embodiment, the warp in the longitudinal direction of the substrate and the optical element cannot be ignored. In this example, as shown in FIG. 50, even if the substrate and the LN chip were warped, the Si convex portion surface 30 was divided into four parts so that the Si convex portion surface 30 functions as a good height reference plane. It was provided in the immediate vicinity of the optical waveguide. Also, the electric wiring 500
Was formed as a coplanar line on the surface of the silica-based optical waveguide under-cladding layer 60c formed in the region between the four divided Si convex portions.

As a result, as shown in FIG. 50, the Si convex portion functions as a height reference plane even when the substrate and the LN waveguide have a considerable amount of warpage. Needless to say, the electrical wiring portion exhibits excellent high frequency characteristics as in the other examples.

The hybrid optical integrated substrate of the present invention has been described above by taking the case of a silica-based optical waveguide formed on a Si substrate as an example. However, the present invention can be applied to other material systems. Needless to say. There is a sufficient difference in the etching rate of the substrate of the optical waveguide with respect to the etchant used for forming the element mounting portion in the optical waveguide, and the substrate and the dielectric optical waveguide function as an etching stop layer. The present invention can be realized by using a combination of If such a combination of the substrate and the dielectric optical waveguide is used, the substrate convex portion functions as a highly accurate height reference surface. From the viewpoint of high frequency characteristics of electric wiring, it is desirable to use an optical waveguide made of a material having a dielectric constant lower than that of the substrate material.

The combination of such a substrate and a dielectric optical waveguide is not limited to a silica optical waveguide / Si substrate, but a silica optical waveguide / alumina ceramic substrate, a silica optical waveguide /
An alumina nitride ceramic substrate, or a system in which a polymer-based dielectric optical waveguide such as a polyimide optical waveguide is used instead of the quartz optical waveguide as the optical waveguide is exemplified.
However, when a substrate having a poor thermal conductivity such as alumina ceramic is used, the heat sink of the optical element is used in the second embodiment.
0 (FIG. 46), it is necessary to take it on another substrate.

In each of the above-described embodiments, an example in which an optical element is mounted is shown. Along with this, an electronic circuit for driving an optical element,
Furthermore, it is of course possible to integrate the signal processing electronic circuit.

(Embodiment 22) FIG. 51 is a perspective view showing the structure of an optical mounting board in a twenty-second embodiment of the hybrid optical integrated circuit of the present invention. In FIG. 51, reference numeral 1 is a substrate, 1a is a substrate concave portion, and 30 is a substrate convex portion. Reference numeral 92 is a dielectric optical waveguide, 92a is a signal optical waveguide, 92b is a monitor optical waveguide, and 93 and 93a are cladding layers. Reference numeral 95 denotes an electric wiring surface of the optical element mounting portion, 9
5a and 95b are a center conductor and an installation conductor as an electric wiring layer, and 96 is a fixing material. The surface of the substrate convex portion 30 functions as a height reference surface of the optical element mounting portion. Further, a thin film electrode 97 for monitoring is provided on this surface.

In the optical mounting substrate shown in FIG. 51, a silicon substrate is used as the substrate 1 and a quartz optical waveguide is used as the optical waveguide circuit 92. The silicon substrate is provided with unevenness having a step of 40 μm. An undercladding layer made of silica glass having a thickness of 42 μm is provided in the recess, and a core dimension of 6 μm × 6 μm and a relative refractive index difference Δ = 0.75 are provided on the undercladding layer.
% Signal optical waveguide 92a and monitor optical waveguide 92
b is formed. The distance between the surface of the convex portion of the silicon substrate 1 and the center of the waveguide core was set to 5 μm in accordance with the dimensions of the optical functional device 100 described later. Optical waveguide for monitor 9
The end portion of 2b is arranged at a position corresponding to the height reference surface formed by the convex portion of the silicon substrate 1, and the end portion of the signal optical waveguide 92a is arranged at a position corresponding to the electric wiring surface 95.
A thin film gold electrode having a thickness of 0.5 μm is formed on the height reference surface 30. There is a step of 10 μm between the surface of the convex portion of the silicon substrate 1 which is the height reference surface and the electric wiring surface 95.
An underclad layer 93a of a silica-based optical waveguide having a thickness of 30 μm is provided below the electric wiring surface 95. The electrical wirings 95a and 95b are gold-plated patterns having a thickness of 4 μm, and solder bumps having a thickness of 4 μm are formed as fixing materials 96 at the ends thereof.

By mounting a desired optical functional element on the optical element mounting portion on the optical mounting board having the above-described structure, the structure shown in FIG.
A hybrid optical integrated circuit as shown in 2 can be formed.
The optical functional device 100 in this embodiment is a semiconductor laser and has a signal port 100a and a monitor port 100b. The arrangement order of the ports and the pitch thereof correspond to the input / output end pitch of the optical waveguides 92a and 92b of the optical waveguide circuit. If the optical functional device 100 is mounted on the optical device mounting portion in the upside-down form, the monitor port 100b of the optical functional device is arranged on the height reference plane 30 of the convex portion of the silicon substrate 1, and the signal port 100a is electrically wired. It is placed on the surface.

FIG. 53 is a sectional view taken along the line III-III 'in FIG. Active layer 100 of semiconductor laser 100
a and 100b are located at a position of 4.5 μm from the device surface. On the other hand, in the hybrid optical integrated substrate, the distance from the surface of the thin film electrode 97 on the height reference plane (silicon convex portion) to the center of the optical waveguide core is 4.5 μm.
Therefore, as shown in the figure, only by mounting the semiconductor laser on the height reference plane, the alignment of the optical waveguide and the semiconductor laser in the height direction can be completed.

By the way, in order to perform the in-plane alignment, it is necessary to monitor the optical coupling efficiency between the semiconductor laser and the optical waveguide. Since the surface electrode 100c below the optical signal port 100a of the semiconductor laser does not contact the electric wiring 95a and the solder bumps 96 on the substrate 1 as shown in FIG. 53, the optical signal port 100a cannot be used for alignment.

However, in this embodiment, the hybrid optical integrated circuit and the optical functional element are provided with the monitor optical waveguide 100a and the monitor port 100b, and the monitor port 1 is provided.
00b is a thin film electrode on the height reference plane 30
Since it is in contact with, it is possible to perform alignment using the monitor port.

Such alignment can be performed by making the semiconductor laser function as a light receiving element. That is, the monitor light is propagated through the monitor optical waveguide, and the received light current of the monitor port for this monitor light is monitored,
We have found the position where this is the maximum.

As active alignment, L
It is also possible to employ a method of causing D100 to emit light and finding a position where the optical output from the monitor optical waveguide is maximum.

Next, as shown in FIG. 54, after alignment is completed,
By heating and reflowing the solder bumps 96, the solder bumps and the semiconductor laser signal port upper surface electrode 100c
Since and are in contact with each other, electrical connection and element fixing between the semiconductor laser and the hybrid optical integrated substrate can be realized. At this time, the contact position between the solder and the optical functional element is set to be slightly laterally displaced from immediately below the port (active layer), so that the stress due to the curing shrinkage of the solder directly acts on the optical signal port of the optical functional element. Can be prevented.

The excessive coupling loss due to the positional shift in this hybrid optical integrated circuit was 0.5 dB or less. This indicates that the surface mounting of the LD can be realized with an accuracy within 1 μm in the hybrid optical integrated circuit of the present embodiment. This is possible because firstly, the surface of the silicon convex portion is used as the height reference surface, and secondly, active alignment is possible for alignment in the in-plane direction.

As described above, in this embodiment,
It is possible to perform “active alignment” for performing centering in the in-plane direction while functioning the optical functional element, and to fix the optical element by solder bumps. For this reason, compared to conventional passive alignment device mounting,
It is possible to realize optical element hybrid integration with higher accuracy, and solve problems such as a decrease in fixing strength due to the use of thin film solder and a large amount of stress generated in the optical functional element, which have been problems in conventional active alignment. it can.

Further, in this embodiment, a silicon substrate having excellent thermal conductivity is used as the substrate, and the surface thereof is provided with irregularities, and the convex portions are used as the height reference plane for mounting the optical functional element. With such a structure, there is an effect that the heat generated by the optical functional element can be efficiently released to the substrate through the silicon convex portion.

Further, in this embodiment, the electric wiring surface of the optical element mounting portion is provided on the quartz optical waveguide cladding layer having a sufficient thickness. With such a structure, a hybrid optical integrated circuit having excellent high frequency characteristics can be realized. That is, in the conventional technique as shown in FIG. 1, the electrical wiring is generally formed directly on the silicon substrate or on an extremely thin oxide film having a thickness of about 0.5 μm. However, such a conventional configuration has a problem that the high frequency characteristics of the electrical wiring portion are significantly deteriorated due to the influence of the silicon substrate which is a semiconductor. This problem is solved in this embodiment by disposing a dielectric layer having a sufficient thickness between the silicon substrate and the electric wiring surface.
In fact, it was confirmed that the electric wiring portion in the hybrid optical integrated circuit of this example has a band extending to about 10 GHz.

(Embodiment 23) FIG. 55 is a schematic perspective view showing the structure of an optical mounting board in a twenty-third embodiment of the hybrid optical integrated circuit of the present invention. The feature of the present embodiment is that, unlike the twenty-second embodiment, a convex portion is provided on the silicon substrate 1 which is the optical element mounting portion, in addition to the height reference plane 30 for the optical functional element, and the electron is formed on the silicon convex portion. The circuit mounting surface 98 is provided,
Further, not only the electrical wiring for the optical functional element but also the electrical wiring to the electronic circuit is provided on the electrical wiring surface 95. Since the other components are the same as those in the twenty-second embodiment,
The same reference numerals are given and the description thereof is omitted.

Even in this case, the same effect as that of the twenty-second embodiment can be obtained, and in addition to this, since the convex portion of the silicon substrate is used also as the electronic circuit mounting surface 98, It is possible to effectively dissipate heat from the electronic circuit mounted on the. That is, the optical mounting board used in the hybrid optical integrated circuit of the present invention functions as an optical / electric hybrid mounting board.

(Embodiment 24) In Embodiment 22 described above, an example in which a silicon substrate having an uneven portion is used as a substrate and a quartz optical waveguide is used as a dielectric optical waveguide is shown, but this is also an object of the present invention. Of course, a combination other than this material system is possible in order to achieve both the alignment of the optical functional element by active alignment and the element fixing by thick film solder such as solder bumps. Below, the example of those combinations is illustrated.

First, the optical waveguide in the twenty-second embodiment is
It goes without saying that the optical waveguide is not limited to the quartz optical waveguide. For example, even if a polymer optical waveguide such as a polyimide waveguide is used, all of the effects exhibited in Example 22 can be realized.

Secondly, a substrate other than the silicon substrate can be applied to the substrate in the twenty-second embodiment. For example, a ceramic substrate, such as an alumina substrate, which has a proven track record as a mounting substrate for an electronic circuit, may be used which has irregularities on its surface. Also, regarding the optical waveguide in this case, the silica-based optical waveguide,
Various material systems such as polymer waveguides can be used.
Thus, when the alumina substrate is used as the substrate, the heat radiation effect is less than that of the twenty-second embodiment, but the other functions can exhibit the same effects as those of the twenty-second embodiment. In particular, the high frequency characteristics of the electric wiring and the expandability of the wiring scale may be superior to those of the twenty-second embodiment.

Thirdly, in the twenty-second embodiment, the substrate having the uneven surface is used, but a substrate having a flat surface may be used instead. FIG. 56 is a perspective view showing a substrate structure when an alumina substrate having a flat surface and a quartz optical waveguide is used as an optical waveguide as an example of this embodiment. The height reference plane 30 of the optical element mounting portion may be formed of the optical waveguide clad layer.

In this case, the accuracy of determining the height between the height reference plane 30 and the centers of the optical waveguide cores 92a and 92b may be lower than that of the twenty-second embodiment. Moreover, when a ceramic substrate is used as the substrate, the heat dissipation effect is also reduced.

However, also in this embodiment, both the active alignment and the thick film solder fixing, which are the objects of the present invention, can be realized at the same time. Moreover, it is of course possible to use a silicon substrate as the surface-flattened substrate. A quartz substrate can also be used as the substrate.

Fourthly, in the twenty-second embodiment, an example of "embedded structure optical waveguide" in which the optical waveguide core is embedded in the clad layer having a sufficient thickness is shown, but the form of the optical waveguide is not limited to this. It is not something that will be done. For example, the conventional technique can be applied to a "ridge type optical waveguide" in which the core is exposed or is simply covered with a thin cladding layer as shown in FIG.

Fifth, the main object of the present invention can be realized by using a material other than the above dielectric material as the optical waveguide.
An example of such a material is a silicon waveguide.

Further, in the above-mentioned Example 22 and the like, solder bumps were used as the fixing material 96 in order to realize the electrical connection and fixing between the optical signal port of the optical functional element and the electrical wiring on the optical waveguide circuit. However, in addition to this, it is also possible to use a material such as a conductive adhesive or a conductive rubber. Also in this case, similarly to the twenty-second embodiment, it is possible to suppress the stress caused by mounting the element from being applied to the optical signal port.

(Embodiment 25) FIG. 57 is a plan view showing a twenty-fifth embodiment of the hybrid optical integrated circuit of the present invention, and FIG. 58 is an enlarged schematic perspective view of the essential portion shown in FIG. is there. The signal optical waveguide 92a of this optical waveguide circuit is
It is composed of an input / output waveguide section I / O, a circulating waveguide section R, and a directional coupling section C that performs optical coupling between the two waveguides, and constitutes a "ring resonance circuit" as a whole. A semiconductor optical amplifier is mounted as an optical functional element 100 in the middle of the circular waveguide section R, and the signal port 100a of this element and the signal optical waveguide are optically coupled. This hybrid optical integrated circuit functions as a "ring laser" as a whole.

Since the "ring resonance circuit" of this embodiment has sharp optical frequency selectivity, it is attempted to integrate the semiconductor optical amplifier 100 in the optical waveguide by active alignment using the signal optical waveguide and the signal port. Then, the optical frequency of the monitor light that can be used is limited. In order to significantly relax the limitation of the optical frequency of the monitor light, in the present embodiment, in the optical waveguide circuit and the semiconductor optical amplifier, respectively,
A monitor optical waveguide 92b and a monitor port 100b are provided, and they are used for centering. That is, the monitoring optical waveguide 92b is arranged outside the circular waveguide R of the optical waveguide circuit, and the signal port 100a of the semiconductor amplifier is arranged.
The monitor port 100b was arranged side by side. Therefore, when mounting the semiconductor amplifier, the monitor optical waveguide having no wavelength selectivity can be used, and the constraint condition on the optical frequency of the monitor light is greatly relaxed.

In particular, if the structure of the optical element mounting portion of the optical waveguide circuit has a two-layer structure of the height reference plane 30 and the electric wiring plane 95 having a height lower than that as shown in FIG. Two
As described in detail in Section 2, low-stress elements can be fixed using thick-film solder or conductive adhesive.

(Embodiment 26) FIG. 59 is a plan view showing the structure of a twenty sixth embodiment of the hybrid integrated circuit of the present invention. The feature of this embodiment resides in that a plurality of optical functional elements are mounted in a row in an optical waveguide circuit. In FIG. 59, reference numeral 100 is an LD array as the first optical functional element,
Reference numeral 101 is a semiconductor modulator array as a second optical functional element. This is a configuration in which a Mach-Zehnder interference circuit type intensity modulation circuit is arrayed. This optical waveguide circuit is
The optical signal output from the D array 100 propagates through the first signal optical waveguide array 220a, is modulated by the modulator array 101, and propagates through the second signal optical waveguide array 221a to the end face of the substrate. It is composed.

This hybrid optical integrated circuit is an "L with external modulator" that modulates the optical output from the LD by the modulator array.
Function as a "D array module". In such a configuration, the signal optical waveguide is divided for mounting the second optical functional element 101, and active alignment using this waveguide is difficult. Further, if the signal port of the modulator array 101 is also designed so that light does not pass through when no power is supplied, it is difficult to perform alignment using the signal optical waveguide 221a.

Therefore, in this embodiment, the monitor optical waveguide 220b connecting the first optical functional element 100 and the end portion of the optical waveguide circuit board on the optical waveguide circuit, and the second optical functional element 101 and the substrate. Monitor optical waveguide 221b connecting the ends
2 systems of monitor optical waveguides are provided.

On the other hand, the LD100 has a monitor port 100
b is provided, and this port 100b functions as a semiconductor laser similarly to the signal port 100a. The port that functions as a semiconductor laser can also function as a light receiving element. The modulator array 101 is provided with a monitor port 101b.
Functions as a light receiving element.

In this embodiment, the optical element mounting portion has the same structure as that of the twenty-second embodiment.

FIG. 60 (A) and FIG. 60 (B) are shown in FIG.
60A is a cross-sectional view of the circuit shown in FIG. 60, and FIG. 60A is a cross-sectional view taken along the line Xa-Xa ′ showing the LD mounting mode.
0 (B) is a cross-sectional view taken along the line Xb-Xb 'showing the modulation array mounting form.

With such a structure, the monitor light is incident on the monitor optical waveguide 220b and the received light current is monitored, whereby the active alignment of the LD 100 becomes possible. Exactly the same, monitor optical waveguide 2
21b can be used to achieve alignment of the modulator array 101.

The arrangement of the monitoring optical waveguide in this embodiment is premised on that the monitor port of the optical functional element has a light receiving function, so that the application is limited to the semiconductor optical element.

(Embodiment 27) FIG. 61 is a plan view showing the structure of a twenty-seventh embodiment of the hybrid optical integrated circuit of the present invention. The feature of this embodiment is that the embodiment 26 shown in FIG.
Unlike the second optical functional element or modulator array 10
The optical waveguide for monitoring 221b for 1 is provided so as to connect the first optical functional element, that is, the LD 100 and the modulator array 101 to each other. Since the other components are the same as those in the twenty-sixth embodiment, the same reference numerals are given and the description thereof will be omitted. That is, the monitor optical waveguide 221b for the modulator 101 merges with the monitor optical waveguide 220b immediately before the LD 100 and is connected to the monitor port 100b of the LD 100.

With such a structure, the optical element can be mounted by the following procedure. That is, first, active alignment of the LD is performed using the monitor optical waveguide 220b. At this time, the LD may be caused to emit light, or the light receiving function may be used. LD
After the mounting is completed, this time, the modulator array 101 is aligned by using the monitor optical waveguide 221b.
At this time, the monitor port 101 may be made to function as a light receiving element while the monitor port 100b of the LD is made to emit light, and the light receiving current may be monitored.

The feature of this method is that it is necessary to connect an optical fiber to the optical waveguide for monitoring and input or output the monitor light at the time of alignment of the first optical functional element. Since the optical waveguide for use is provided, there is no need for fiber connection in the second optical functional element alignment, and the alignment process can be simplified.

(Embodiment 28) FIG. 62 is a plan view of a twenty-eighth embodiment of the hybrid optical integrated circuit of the present invention. 63 (A) and 63 (B) are plan views for explaining the alignment method of the optical functional element to be fixed on the circuit shown in FIG. 62, and FIG. 63 (A) shows the LD array. FIG. 63 (B) shows alignment locking of the modulator array.

The feature of this embodiment is that, unlike the twenty-seventh embodiment,
As a monitoring optical waveguide for the modulator 101, in addition to the waveguide connected to the LD, a waveguide connected to the end portion of the optical waveguide circuit board is also provided.

With such an arrangement, the means for monitoring the alignment with respect to the modulator 101 is increased, and as a result, the alignment is possible even with the optical functional element made of a material other than the semiconductor element. The alignment procedure in this configuration will be described below.

The alignment of the optical integrated circuit having such a configuration will be described with reference to FIGS. 63 (A) and 63 (B). First, monitor light is propagated through the monitor optical waveguide 220b, and the monitor port 10 of the LD array 100 is
The optical waveguide for signal 22 while monitoring the optical coupling with 0b.
0a and the optical signal port 100a are aligned,
The LD array 100 is fixed. Subsequently, the modulator array 101 may be centered and fixed using the monitor optical waveguide 221b and the monitor port 101b. As a monitoring method at this time, the monitor port 101b is used as a passive waveguide, the monitor light incident on the monitor optical waveguide 221b is propagated to the monitor port 101b, and finally the LD
It is incident on the monitor port 100b of 100. At this time, the monitor port 100b of the LD 100 may be made to function as a light receiving element to find a location where this light receiving current is maximum. Alternatively, the light propagating direction may be reversed to cause the LD monitor port 100b to emit light, and the output light from the monitor waveguide 221b at this time may be monitored.

According to this method, since the monitor port of the modulator array is used as a passive waveguide, it goes without saying that the optical functional element 101 is made of a semiconductor material as in the present embodiment, and other than semiconductors. Optical element, eg LiN
It can be applied even when a dielectric electro-optic crystal such as bO ₃ or a magneto-optic crystal is used.

As described above, in this embodiment,
In hybrid integration of multiple optical functional elements, a monitor optical waveguide was provided to correspond to each element.
It is possible to mount a plurality of elements in cascade in the optical waveguide circuit.

(Embodiment 29) FIG. 64 is a plan view showing a twenty-ninth embodiment of the hybrid optical integrated circuit of the present invention. In this embodiment, a plurality of monitor waveguides 92b and 92c or monitor ports 100 having different widths are used as the monitor waveguide of the optical waveguide circuit or the monitor port of the optical functional element.
The feature is that b and 100c are provided.

As shown in FIG. 64, both the monitor ports 100b and 100c of the optical functional element are formed to have the same width, while the width of the monitor optical waveguide 22b of the optical waveguide circuit is set to be the same as that of the signal optical waveguide 92a. , Monitor optical waveguide 9
For 2c, the waveguide width is made wider than for 92b.

With such a structure, coarse adjustment of the centering is performed using the monitor optical waveguide 92c and the monitor port 100c, and then fine adjustment is performed using the monitor optical waveguide 92b and the monitor port 100b. It becomes possible to do. By such two-stage alignment, the time required for active alignment can be shortened.

(Embodiment 30) FIG. 65 is a plan view showing a thirtieth embodiment of the hybrid optical integrated circuit of the present invention. The feature of this embodiment is that, contrary to the 29th embodiment, the monitor port 100b of the optical functional element has the same width as the signal port and the monitor port 100c is set wider than the signal port.

Even with such a configuration, as in the twenty-ninth embodiment, it is possible to shorten the time required for active alignment by performing two-step alignment of coarse adjustment → fine adjustment.

(Embodiment 31) FIGS. 66 and 67 show the structure of a first embodiment of an optical sub-module which can be mounted on the hybrid optical integrated circuit of the present invention, and FIG. 66 shows the optical sub-module of this embodiment. 67 is a perspective view showing the structure of an optical element 301 and a carrier 302 which are the constituent elements of FIG. 67, and FIG. 67 is a sectional view taken along the line AA ′ of FIG. 66. The optical element 301 is an array semiconductor optical amplifier, 311 is its active layer, and four arrays are formed in this active layer 311 at intervals of 400 μm. These active layers 311 are separated from the optical element surface 312 by 6 μm. There is. An active layer side electrode 313a corresponding to each active layer 311 is formed on the optical element surface 312, and a ground side electrode 313b is formed on the back surface opposite to the optical element surface 312. Reference numerals 314 are optical element height reference planes, respectively. As shown in FIG.
It is provided at a position lower than 11 to 3 μm on the back surface side, that is, at a position lower than the optical element surface 312 by 9 μm. Three
Reference numeral 15 denotes an optical element lateral direction reference surface, which is formed orthogonal to the optical element surface 312 and the optical element height reference surface 314. The position of the reference plane 315 is 400 μm apart from both ends of the outer active layer 311 among the four active layers 311. In this embodiment, the optical element lateral reference surfaces 15 are provided on both the left and right sides, but the function can be sufficiently achieved by only one side.

The carrier 302, as shown in FIG.
It is formed by providing three steps on the surface of the i substrate. The carrier convex portion 321 is an "optical element holding surface 321a" for fixing the optical element height reference surface 314 of the optical element 301 in contact therewith.
At the same time, it also serves as a "carrier height reference surface 321b" which is a reference surface when mounted on a mounting board. That is, in the general case, the "optical element holding surface" and the "carrier height reference surface" are separately formed as surfaces having different heights, but in the present embodiment, they are the same surface. The area 325 surrounded by the carrier protrusions 321 is 1 to 1 from the carrier protrusions 21.
It is formed with a step difference of 5 μm. This area 325
2 μm thick gold carrier electrical wiring 3 on the surface of
24 are formed. Solder pattern 32 is attached to this tip.
6 is provided. This area 325 is the optical element 301.
Of the active layer side electrode 313a. The peripheral region 323 is 40 μm from the carrier protrusion 321.
Is formed with a step, and the carrier electric wiring 324 is also continuously formed on this surface. This area 32
3 fulfills the function of electrical connection with the electrical wiring on the optical mounting board side.

The carrier 302 having a multi-step structure of this embodiment was formed by repeating anisotropic etching of a Si substrate. That is, the convex portion 321 of the Si substrate was formed first, and then the step of the region 325 was formed. When the steps are formed by such anisotropic etching, the side surfaces between the steps are not vertical and the angle of about 55 ° is formed in the region 32.
The electric wiring 324 can be formed between the step between the No. 5 and the region 323 without breaking.

FIG. 67 is a sectional view showing a state of the optical submodule in which the semiconductor optical amplifier 301 of FIG. 66 is fixed to the carrier 302 as described above, with a section taken along the line AA ′ of FIG. The optical element height reference surface 314 of the semiconductor optical amplifier 301 is used as the carrier holding surface 321 of the carrier 302.
It was mounted in contact with. In this state, the optical element active layer side electrode 313a and the carrier electric wiring 324 provided in the carrier region 325 are heated by the carrier 302 to be soldered 32.
By reflowing 6, the connection was fixed. Since the step between the carrier regions and the step between the optical element height reference surface and the active layer are set as described above, the active layer 311 is 3 μm away from the carrier height reference surface (carrier holding surface) 321b.
It is located above.

By thus forming the optical element in the form of an optical sub-module, it is easy to inspect the characteristics of the optical element in advance. That is, the optical element active layer side electrode 31 has already been formed.
Since 3a is connected to the carrier electric wiring 324,
The inspection can be performed without directly touching the surface of the optical element.

(Embodiment 32) FIG. 68 shows a second optical sub-module which can be mounted on the hybrid optical integrated circuit of the present invention.
It is sectional drawing which shows the Example of.

In the optical sub-module according to the present invention, the distance between the active layer of the optical element and the carrier reference plane can always be unified to a constant value even when optical elements having different dimensions are used. In the above-mentioned Example 31, in the optical element height reference plane 314
The step between the active layer 311 and the active layer 311 was 3 μm.
Consider a case where an optical element having a step of 5 μm is mounted. In this case, as shown in FIG. 68, the carrier 3
02 optical element holding surface 321a and carrier height reference surface 32
A step of 2 μm may be provided between the step and 1b.

(Embodiment 33) FIG. 69 shows a third optical sub-module which can be mounted in the hybrid optical integrated circuit of the present invention.
It is sectional drawing which shows the Example of. 6 μm from active layer 311
The optical element surface 312 at the height of the optical element height reference plane 31
69, the optical element height reference plane 314 of the carrier 302 may be set to be 9 μm higher than the carrier height reference plane 321a, as shown in FIG.

By setting the dimensions as in Example 31 or 32, the step difference between the carrier height reference plane and the active layer is shown in FIG. 67 regardless of the dimension of the optical element.
The thickness can be 3 μm as in the case of.

(Embodiment 34) FIG. 70 is an exploded view showing a structure of a thirty-fourth embodiment of a hybrid optical integrated circuit of the present invention using the first embodiment of the optical submodule shown in FIGS. 66 and 67. It is a perspective view. Reference numeral 304 denotes an optical mounting substrate, and an optical waveguide portion 342 is provided on the stepped Si substrate 341.
And an electric wiring 346 as a board electric wiring and an optical element mounting portion 348 are formed.

The optical waveguide portion 342 is formed in the concave portion of the Si substrate and has a three-layer structure of an underclad 342a (thickness 30 μm), a core 342c (thickness 6 μm × width 6 μm) and an overclad 342c (thickness 30 μm). Type silica-based optical waveguide.

The substrate electric wiring 346 is formed on the surface of the overclad 342c, and has a coplanar structure composed of a central conductor 346a and a ground conductor 346b so that high frequency operation is possible. These wirings were formed by vapor-depositing gold (thickness 5 μm) after forming the overclad and patterning. This wiring layer has a sufficient thickness (66μ
Since it is formed on quartz glass having m) and a small dielectric constant, it exhibits good electric characteristics. Also, the board electrical wiring 3
A solder pattern 327 is vapor-deposited on the tip of the central conductor 346a of the wiring 46 for electrical connection with the optical sub-module.
It is formed by patterning.

The optical element mounting portion 348 is formed in a region including the Si convex portion 343. The height of the surface of the Si convex portion 343 corresponds to the height of the upper surface of the optical waveguide underclad 342a, and functions as a height reference surface (hereinafter referred to as a substrate height reference surface 343) when the optical submodule is mounted. That is,
The height from the substrate height reference surface 343 to the center of the optical waveguide core 342b is 3 μm, which is equal to the height from the carrier height reference surface 321b to the active layer 311 of the optical submodule of the thirty-first embodiment. The Si recessed region 348 other than the substrate height reference plane 343 is an optical element insertion groove 349 and has a depth of about 110 μm from the substrate height reference plane 343.
On the bottom surface of the groove 349, a grounding electric wiring layer 347 made of gold having a thickness of 2 μm is provided.
It is formed at the same time as 6. Since the grounding electric wiring layer does not require fine patterning, it can be easily formed on the bottom of such a deep groove. A wiring take-out portion 349a is provided at an end portion of the bottom surface of the groove 349, and the lead 345 forms an electric wiring layer 347 for grounding of the optical mounting board 304 and a grounding conductor 346b.
And are connected.

The optical mounting board 304 of the present embodiment is a substrate electric substrate for taking out the electrode 313a on the optical element active layer 311 side even when the arrayed optical element 301 is inserted in the middle of the optical waveguide as described above. Since the wiring may be formed on the surface of the optical waveguide, even a relatively fine electric wiring pattern can be easily formed. In the conventional mounting of the optical element upside down, the board electric wiring must be formed on the bottom surface of the stepped board, which is difficult.

Next, the optical element 3 is mounted on the optical mounting board 304.
70, a process of manufacturing a hybrid optical integrated circuit by mounting an optical sub-module including 01 and a carrier 302,
This will be described with reference to FIGS. 71 and 72. FIG. 71 is FIG.
0 is a sectional view taken along the line BB ′ of FIG. 0, and FIG. 72 is a sectional view taken along the line CC ′ of FIG. 70.

70 and 71, the carrier height reference plane 321 of the optical sub-module and the substrate height reference plane 343 of the optical mounting board are brought into contact with each other, so that the heights of the optical element active layer 311 and the optical waveguide core 342a are increased. The alignment in the depth direction can be easily completed. In this embodiment, in the lateral direction (the plane direction of the Si substrate 341 and the direction orthogonal to the optical waveguide), the optical coupling rate between the optical waveguide and the optical element is monitored and the optimum position is set. After the alignment was completed, the conductive adhesive 351 was dropped on the bottom surface of the optical element insertion groove 349 of the optical mounting board to fix the optical sub-module and the optical mounting board.

Finally, as shown in FIG. 72, the solder 327 provided at the end of the electrical wiring of the substrate on the optical mounting substrate is reflowed, and the electrical wiring of the carrier 302 of the optical submodule and the substrate 30 are reflowed.
The fabrication of the hybrid optical integrated circuit is completed by making electrical connection with the electrical wiring of 4.

In this embodiment, the solder reflow is performed by heating the entire substrate, but a method of locally heating the connection portion is also possible.

In the conventional optical element upside-down mounting mode, the optical element fixing and the electrical connection had to be performed in one step, whereas the mounting step of the present embodiment is as described above. It has become possible to separate the process of aligning and fixing the optical submodule and the optical mounting board from the process of connecting the electrical wiring of both.

Further, in the case of an optical element having a large number of electric wiring terminals, the conventional method is apt to cause a failure such that terminals which are not electrically connected are produced, and the yield is apt to be lowered. On the other hand, according to the present invention, since electrical connection may be performed after fixing the optical element, it is possible to manufacture a hybrid optical integrated circuit with a good yield even for an optical element having a large number of electrical connection terminals.

Further, as described above, by using the optical sub-module of the present invention and the hybrid optical integrated circuit, the dimension in the height direction of the optical mounting board can be obtained even when the optical elements having different dimensions in the height direction are used. Need not be changed. The height between the reference planes of the optical submodule as shown in FIG. 67, FIG. 68 or FIG.
If the height between 1, 321a and 321b and the optical element active layer 311 is 3 μm, the optical mounting substrate of this embodiment can be applied to any optical element.

As described above, according to the present invention, there is a problem in the conventional hybrid optical integrated circuit of the upside down mounting type. 1) Multi-product, plural element mounting, 2)
It is possible to solve all the difficulties related to the formation of electric wiring on the substrate and 3) the preliminary inspection of the optical element.

(Embodiment 35) FIG. 73 is a perspective view showing the structure of a fourth embodiment of an optical submodule which can be mounted on the 35th embodiment of the hybrid optical integrated circuit of the present invention.
This embodiment is different from the optical submodule of the 31st embodiment in that the optical submodule is provided with a lateral alignment reference surface and the step between the region 325 and the region 323 is eliminated. .

As shown in FIG. 73, the optical element 301 is the same array type semiconductor optical amplifier as that of the 31st embodiment, and the various dimensions are also the same. The carrier 302 has the optical element holding surface 321a and the carrier height reference surface 3 as in the thirty-first embodiment.
21b are formed as the same surface without a step, and an optical element mounting lateral reference surface 322a for laterally positioning the optical element is formed on the inner side surface of the optical element holding surface 321a. When mounting the optical element 301 on the carrier 302, the optical element height reference surface 314 and the optical element holding surface 321 are mounted.
It is possible to determine the relative positions of the carrier 302 and the optical element 301 by bringing them into contact with each other and by bringing the optical element lateral reference surface 315 and the optical element mounting lateral reference surface 322a into contact with each other. Carrier height reference surface 32 of the carrier 302
A carrier lateral direction reference surface 322b is formed on the outer side surface of 1b, and the carrier lateral direction reference surface 322b and the optical element mounting lateral direction reference surface 322a are separated by 300 μm. The structure and dimensions of the carrier 302 other than those described above are the same as in the case of the thirty-first embodiment.

Therefore, the optical element 301 is replaced by the carrier 30.
When mounted in No. 2, the distances between the optical element active layer 311 and the carrier height reference plane 321b and the carrier lateral reference plane 322b are 3 μm and 700 μm, respectively.

(Embodiment 36) FIG. 74 is a sectional view showing the structure of a hybrid optical integrated circuit according to the 36th embodiment of the present invention. This embodiment is characterized in that it includes the optical sub-module of the previous embodiment 35.

The structure of the optical mounting board on which the optical sub-module of Example 35 is mounted is the same as that shown in FIG. However, in this embodiment, the device mounting groove side wall 3 is located from the center of the leftmost optical waveguide core.
The distance to 48b is set to 700 μm. The other dimensions are the same as in the case of Example 334.

In this embodiment, when mounting the optical sub-module, as shown in FIG. 74, the carrier height reference plane 321b of the optical sub-module is brought into contact with the substrate height reference plane 343 of the optical mounting board, and The optical device active layer 311 and the optical waveguide core 342 are brought into contact by bringing the carrier mounting lateral reference surface 322b and the device mounting groove side wall 348b into contact with each other.
The alignment with b is completed. After this, FIG. 70 to FIG.
A hybrid optical integrated circuit can be manufactured through the same steps as those of the embodiment 34 shown in FIG.

Even if the dimensions of the optical element are different, if the dimensions of the height reference plane and the lateral reference plane provided on the carrier are appropriately set, the optical element active layer 311 and the carrier height reference plane 321b and the carrier are always provided. Mounting lateral reference plane 322
The distance from a can be set to 3 μm and 700 μm, respectively. Therefore, according to this embodiment, the hybrid optical integrated circuit can be formed without changing the dimensions of the optical element mounting portion of the optical mounting substrate even if the dimensions of the optical element are changed. In addition to this, the various effects obtained in the previous embodiments can be realized in exactly the same manner in this embodiment.

(Embodiment 37) FIG. 75 is an exploded perspective view showing the structure of a fifth embodiment of an optical submodule which can be mounted on the 37th embodiment of the hybrid optical integrated circuit of the present invention. In this embodiment, transparent quartz glass is used as the material of the carrier 302. Compared with the carrier of Example 31, an optical element positioning marker 210 and a carrier positioning marker 230 are provided on the optical element holding surface 321a and the peripheral region 323, respectively, which is a structural difference. Further, the photo-element electrode extraction region 325 and the peripheral region 323 have the same height. Other configurations are shown in FIG.
This is the same as the carrier structure of the optical sub-module of Example 33 shown in FIG. The optical element 301 has an active layer side surface 312 as an optical element height reference surface 314, and a marker (not shown) corresponding to the optical element positioning marker 210 is formed thereon.

Since transparent quartz glass is used as the carrier in this embodiment, when the optical element 301 is mounted on the carrier 302, the optical element and the marker formed on the carrier can be observed through the transparent carrier. Therefore, the optical element height reference surface 314 and the carrier holding surface 321a are brought into contact with each other, and the marker formed on the optical element surface and the optical element positioning marker provided on the carrier are mounted so as to overlap each other. Achieved accurate alignment in both directions.

Further, in this embodiment, since the electric wiring 324 is a coplanar wiring and is formed on the surface of quartz glass having a small dielectric constant, it is compared with the previous embodiment using the Si substrate as the carrier 302. And has excellent high frequency characteristics.

(Embodiment 38) FIG. 76 is an exploded perspective view showing the structure of a 38th embodiment of the hybrid optical integrated circuit of the present invention. This embodiment is characterized in that the optical sub-module of Embodiment 37 shown in FIG. 75 is mounted on the optical mounting board 304. Except for the point that the substrate marker 410 is provided on the overclad of the optical waveguide 342, the other structure is almost the same as that of the embodiment 34 shown in FIG. When mounting the optical sub-module on this board, the board marker 41
0 and the carrier positioning marker 230 may be aligned, and the carrier height reference plane and the substrate height reference plane may be brought into contact with each other and fixed.

The quartz glass carrier of this example has a markedly lower thermal conductivity than the Si carriers of Examples 31 and 32. However, if it is mounted on the optical mounting board 304 of FIG. 76, the optical mounting board itself functions as a heat sink, so that no problem occurs.

(Embodiment 39) FIG. 77 is a perspective view showing the structure of a sixth embodiment of an optical submodule which can be mounted on the hybrid optical integrated circuit according to the 39th embodiment of the present invention.
In this embodiment, the carrier 302 is formed by using a ceramic substrate having a multilayer electric wiring 324 on the surface and inside. The carrier (ceramic substrate) 302 has a vertical wiring 324h for connecting the electric wiring on the upper and lower surfaces inside.
Is formed on the lower surface of the ceramic substrate 302, is connected to the electrode of the optical element 301, and is taken out again from the lower surface via the wiring 324s on the upper surface of the substrate.

The optical element holding surface 321a and the carrier height reference surface 321b are made of polyimide. Such a structure can be realized by forming a thick polyimide film on a ceramic substrate and then removing unnecessary portions of the polyimide by etching.

By using this optical sub-module, the hybrid optical integrated circuit of the present invention can be obtained by mounting the optical sub-module on the optical mounting board in the same manner as the other embodiments described above.

In this embodiment, since the ceramic substrate is used as the carrier of the optical sub-module, good electric characteristics can be obtained and multilayer electric wiring can be easily realized. Further, since the electric wiring can be provided on the carrier, the preliminary inspection of the optical element becomes extremely easy.

(Embodiment 40) FIG. 78 is a perspective view showing the structure of a seventh embodiment of an optical submodule which can be mounted on the 40th embodiment of the hybrid optical integrated circuit of the present invention.
The carrier 302 of the present embodiment is an uneven Si substrate 30.
2a, a quartz glass layer 302b as a dielectric layer having a sufficient thickness formed in the concave portion thereof, an electric wiring 324 formed on the dielectric layer 302b, and an optical element holding surface 321a formed in the Si convex portion. The carrier height reference surface 321b is a basic constituent element.

By using the carrier having the laminated structure of the Si substrate excellent in thermal conductivity and the quartz glass having a sufficient thickness as described above, 1) the electric wiring is formed on the surface of the quartz glass layer having a small dielectric constant. Therefore, good high frequency characteristics can be obtained as in the case of Example 33. 2) Si is exposed on the optical element holding surface and the carrier height reference surface, so that the optical element height reference surface and the substrate height reference surface are Since they are in contact with each other, an effect that a high heat dissipation effect is obtained can be obtained.

As the dielectric layer, a polymer dielectric material such as polyimide may be applied instead of quartz glass.
When polyimide is used, it is easy to make the electric wiring multi-layered and have a high density, and it is suitable for mounting a large-scale optical integrated chip having a large number of electric wiring such as a matrix optical switch.

(Embodiment 41) FIG. 79 is an exploded perspective view showing the structure of an eighth embodiment of an optical submodule mountable on the 41st embodiment of the hybrid optical integrated circuit of the present invention, and FIG. It is sectional drawing which follows the DD 'line of FIG.
In this embodiment, as shown in FIG. 79, the carrier 302
Is composed of an uneven Si substrate 302a and a wiring film 302b having electric wiring. An optical element holding surface 321a and a carrier-high reference surface 321b are formed in the convex region of the Si substrate 302a. On the wiring film 302b, the signal wiring 3 is formed on the surface of the polyimide film.
24a is provided, and a microstrip wiring provided with a ground wiring 324b is formed on the back surface. Film 3
A window 352 is provided at 02b. Inside the window 352, an inner lead 324c for connecting the signal wiring 324b and the optical element active layer side electrode extends. Further, an outer lead 324d connected to the signal wiring 324a and an outer lead 324e connected to the ground wiring 324b are provided on the outer peripheral portion of the film 302b.

This optical submodule is manufactured by the following procedure. That is, first, the optical element active layer side electrode 313a
And the inner lead 324c of the wiring film are connected by soldering, and then the convex portion of the Si substrate 302a is inserted from the window 352 of the wiring film, and the optical element height reference surface 314 of the optical element 301 and the optical element lateral reference The surface 315 is brought into contact with and fixed to the optical element holding surface 321a and the optical element mounting lateral reference surface 322a, respectively.

(Embodiment 42) FIG. 81 is a perspective view showing a structure of a forty-second embodiment of the hybrid optical integrated circuit of the present invention. This embodiment is characterized in that it includes the optical sub-module of the 41st embodiment.

The structure of the optical mounting board 304 of this embodiment is shown in FIG.
0 to the same as Example 34 shown in FIG. 72. After the carrier height reference plane and the carrier horizontal direction reference plane of the optical sub-module and the substrate height reference plane and the substrate horizontal direction reference plane of the optical mounting board are respectively fixed in contact with each other, the outer leads 324d of the optical sub-module are optically mounted. The board electrical wiring 346 on the overclad of the board 304 was electrically connected.

As described above, the optical submodule in this embodiment is constructed by combining the carrier having the concave-convex shape Si substrate having the positioning function and the wiring film having the electric wiring function. In particular, the inner connection was used to electrically connect the wiring film and the optical element electrode. As a result, the stress applied to the optical element can be greatly reduced as compared with the structures of Examples 34, 36 and 38 in which the optical element electrode is directly connected to the electric wiring provided on the carrier surface. This greatly improves the reliability of the optical device. At the same time, by using the inner lead, the yield of the process of electrically connecting the optical element electrode and the optical sub-module electrical wiring can be greatly improved. Further, since the microstrip line can be easily formed on the wiring film, the wiring density can be increased. It is easy to form this electric wiring not only on the surface of the film but also inside the film to form a multilayer electric wiring. In addition to this, since the outer lead extends from the optical sub-module, there is an effect that a pre-inspection of the optical element before mounting on the optical mounting board can be performed very easily.

In the hybrid optical integrated circuit according to the present embodiment, the optical submodule is positioned on the optical mounting board.
Since the step of fixing and the step of electrically connecting the optical element electrode and the substrate electric wiring can be separated, the manufacturing yield can be greatly improved.

[0293]

As described above, the mounting substrate for hybrid optical integration according to the present invention is suitable for the disadvantage of the large dielectric loss at high frequencies of the Si substrate, which has a proven record as a substrate for a low-loss silica optical waveguide. The problem is solved by using a thick quartz buffer layer, and from the viewpoint of high-precision optical bench function, mounting the array optical element does not cause an increase in the coupling loss due to the optical waveguide and the axis shift. The thickness of the quartz optical waveguide is optimized so that the warpage of the quartz optical waveguide becomes small. Therefore, it can be used as an optical / electrical mounting substrate in which an active element is accurately mounted on an optical waveguide and which is driven by an excellent high frequency characteristic.

The high frequency electric characteristics are further improved by increasing the specific resistance of the Si substrate, and even if the thickness of the quartz layer between the coplanar line and the Si substrate is made thinner, the sufficiently high frequency characteristics can be obtained. Can be kept. Therefore, a structure in which an underclad layer having a thickness of about 30 μm, which has a sufficient track record as an optical waveguide, is used, and the coplanar line is lower than the core layer, is possible, and the application range can be expanded.

Furthermore, by using an uneven Si substrate, forming a lower clad layer of the silica-based optical waveguide in the concave portion, and exposing the convex portion to the optical element mounting portion and using it as a height reference surface, it is possible to obtain a higher precision. It can be equipped with an optical bench function. In this structure, the Si substrate having excellent thermal conductivity can be used as the heat dissipation plate of the optical element or its driving IC through the Si terrace.

Further, by forming a fiber guide groove in this Si substrate, it becomes possible to connect the fiber to the silica optical waveguide without alignment.

The hybrid optical integrated substrate of the present invention has a basic structure of "optical waveguide substrate with terrace" in which a dielectric optical waveguide is formed in a concave portion on a substrate having irregularities, and the convex portion serves as an optical element mounting portion. Since the electric wiring layer is formed on the dielectric optical waveguide formed in the concave portion of the substrate, the effect is that the substrate having a relatively low resistivity (for example, Si
It has become possible to exhibit excellent high-frequency characteristics without affecting the electrical characteristics of the board, even if a board is used, or even if the board has a relatively high dielectric constant (for example, an alumina ceramic board). .

Further, the substrate convex portion of the optical element mounting portion is divided into two or more parts, the dielectric optical waveguide layer is formed in the region between them, and the connection between the optical element and the electric wiring on the substrate is made. In the hybrid optical integrated substrate of the present invention in which the electrode pad portion of is provided on this dielectric optical waveguide layer, all the electric wiring portions can be formed on the dielectric optical waveguide layer, so that the high frequency The characteristics have been dramatically improved, and at the same time,
Since the upper surface of the convex portion of the substrate can be used as a height reference surface for mounting the optical element, it is possible to mount the optical element with high accuracy.

In the hybrid optical integrated circuit of the present invention, the optical waveguide circuit is provided with the signal optical waveguide and the monitor optical waveguide, and the optical functional element is provided with the signal port corresponding to the waveguide arrangement of the optical waveguide circuit. A monitor port is provided so that the optical waveguide for monitoring of the optical waveguide circuit and the monitor port of the optical functional element are optically coupled, and at the same time, the optical waveguide for signal and the signal port are optically coupled, while the optical functional element is coupled to the optical waveguide circuit. It can be installed on the optical element mounting part above. Therefore, the optical waveguide for signal has a function such as wavelength selectivity / optical frequency selectivity, or the signal port of the optical functional element has various functions. Even if it becomes difficult to perform active alignment using the signal port and the signal port, active alignment using the monitor optical waveguide and the monitor port becomes possible.

Further, a height reference plane having a thin film electrode formed on the surface and an electric wiring plane having a height lower than that are provided in the optical element mounting portion. By arranging the height reference plane at the position corresponding to the monitor optical waveguide and arranging the electric wiring plane at the position corresponding to the signal optical waveguide, the optical functional element and the optical It became possible to perform active alignment with the waveguide and to fix the element using thick film solder such as solder bump. For this reason, high positioning accuracy between the optical waveguide and the optical functional element is realized, and since the upper surface of the signal port of the optical functional element does not come into direct contact with the substrate, stress caused by mounting the element is not applied to the signal port. Can be prevented.

Furthermore, if a substrate having irregularities is used as the substrate and a dielectric optical waveguide circuit is used as the optical waveguide circuit, the height setting accuracy of the height reference plane of the optical element mounting portion is greatly improved and the There is also an effect that the high frequency characteristics of the wiring portion are improved.

Furthermore, if a silicon substrate having excellent thermal conductivity is used as the above-mentioned substrate, in addition to the above-mentioned effects, the effect of greatly improving the heat dissipation characteristics for the optical functional element is produced.

Furthermore, if the monitoring optical waveguide on the optical waveguide circuit is arranged so as to connect between the optical functional element and the end portion of the optical waveguide circuit and, if necessary, between the optical functional elements, a plurality of optical waveguides can be provided in the optical waveguide. It is also possible to mount the optical function elements of (1) in tandem, and, in addition to the semiconductor optical elements, hybrid integration of optical function elements made of various materials other than semiconductors is possible.

In the optical submodule of the present invention, the active layer side of the optical element is brought into contact with the carrier having the electric wiring function for taking out electrodes on the optical element active layer side and the positioning function for positioning the optical element and the optical mounting substrate. It is mounted and formed as described above. As a result, it becomes possible to form electric wiring having excellent high-frequency characteristics inside the optical sub-module, and there is an effect that the high-speed characteristics of the optical element are significantly improved. In addition, it becomes possible to perform a pre-inspection of optical element characteristics prior to mounting on an optical mounting board very easily. Furthermore, there is an effect that the distance from the positioning reference plane of the carrier to the optical element active layer can be set to a standardized value regardless of the optical element size.

Further, in the hybrid optical integrated circuit of the present invention, since it is not necessary to form a fine electric wiring pattern on the bottom of the element mounting portion where a large step is formed, the embedded optical waveguide may be used. Regardless, it became possible to mount not only single-end type but also double-end type optical elements. Furthermore, it has become possible to mount various types of optical elements with different dimensions. Furthermore, since the electrical wiring is provided on the carrier and connected to the optical element in advance before mounting it on the board, the difficulty of performing optical alignment and electrical connection at the same time during mounting work is eliminated, and the work is significantly The effect is that it becomes easier.

[Brief description of drawings]

FIG. 1 is a perspective view showing the structure of a Si optical bench.

FIG. 2 is a characteristic diagram showing high frequency characteristics expected from the structure of FIG.

3A and 3B show two kinds of optical waveguide structures, and FIG. 3A is a cross-sectional view showing an optical mounting substrate having a ridge type optical waveguide structure;
(B) is a sectional view showing an element mounting portion provided on the optical mounting board of (A), (C) is a sectional view showing an optical mounting board of an embedded optical waveguide structure, and (D) is a sectional view. It is sectional drawing which shows the element mounting part provided on the optical mounting board of (C).

FIG. 4 is a schematic perspective view showing an optical mounting substrate having a ridge type optical waveguide structure.

FIG. 5 is a schematic perspective view showing an optical mounting substrate having an optical waveguide structure with a Si terrace.

FIG. 6 is a perspective view showing an example of a configuration of a conventional hybrid optical integrated circuit.

FIG. 7 is a perspective view showing another example of the configuration of a conventional hybrid optical integrated circuit.

FIG. 8 is a cross-sectional view showing an example of the configuration of a conventional optical semiconductor device.

FIG. 9 is a perspective view showing a first embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 10 is an overall perspective view for explaining a second embodiment of the hybrid integrated circuit of the present invention.

11 is a cross-sectional view near the optical element mounting portion of the circuit shown in FIG.

12 is a cross-sectional view taken along the plane AA ′ in FIG.

13 is a cross-sectional view taken along the plane BB ′ in FIG.

FIG. 14 shows an embodiment of a method for manufacturing a hybrid optical mounting substrate of the present invention, (A) is a cross-sectional view showing a step of forming a silica-based optical waveguide, and (B) is for an optical element and It is sectional drawing which shows the process of forming the Si terrace for electronic circuits, (C) is sectional drawing which shows the process of removing the polyimide layer formed on the terrace of (B), and exposing a terrace, (D). FIG. 6A is a cross-sectional view showing a step of forming an electric wiring portion on a polyimide layer.

FIG. 15 is a perspective view showing the structure of a third embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 16 shows another example of the method for manufacturing the hybrid optical mounting substrate of the present invention, (A) is a cross-sectional view showing a step of forming a step corresponding to Si terraces on the substrate,
(B) is a cross-sectional view showing a step of forming an under-cladding layer such as a silica-based optical waveguide in a concave portion of the substrate, (C) is a cross-sectional view showing a step of forming a core pattern and an over-cladding layer, (D). FIG. 6E is a cross-sectional view showing the step of exposing the Si terraces, and (E) is a cross-sectional view showing the step of forming the electric wiring portion.

FIG. 17 is a perspective view of a fourth embodiment of the hybrid optical integrated circuit of the present invention.

18 is a cross-sectional view taken along the line AA of FIG.

FIG. 19 is a graph showing the radius of curvature r of the substrate and the axis shift between the LD array and the optical waveguide core.

20 is a perspective view corresponding to a case where the array optical element in FIG. 18 is changed to a single optical element.

21 is a cross-sectional view taken along the plane AA of FIG.

22 is a side sectional view of FIG.

23 is a side sectional view of the coplanar line portion of FIG. 18 with its position lowered.

FIG. 24 is a side sectional view of the underclad shown in FIG. 18 having a large thickness and the coplanar line portion formed on the underclad.

FIG. 25 is a perspective view of a fifth embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 26 is a cross-sectional view taken along the line DD of FIG.

FIG. 27 is a perspective view of a sixth embodiment of the hybrid optical integrated circuit of the present invention.

28 is a cross-sectional view taken along the plane CC of FIG.

FIG. 29 is a perspective view showing a seventh embodiment of the hybrid optical integrated circuit of the present invention.

30 is a cross-sectional view taken along the line EE of FIG.

FIG. 31 is a perspective view showing an eighth embodiment of the hybrid optical integrated circuit of the present invention.

32 is a cross-sectional view taken along the line XX of FIG.

FIG. 33 is a perspective view showing a ninth embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 34 is a perspective view showing an eleventh embodiment of a hybrid optical integrated circuit of the present invention.

FIG. 35 is a perspective view showing a twelfth embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 36 is a sectional view showing a thirteenth embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 37 is a sectional view showing a fourteenth embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 38 is a perspective view showing an optical mounting board in a fifteenth embodiment of the hybrid optical integrated circuit of the present invention.

39 is a cross-sectional view taken along the plane AA ′ of FIG. 38.

FIG. 40 is a perspective view showing an optical mounting board in a sixteenth embodiment of the hybrid optical integrated circuit of the present invention.

41 is a cross-sectional view taken along the plane BB ′ of FIG. 40.

FIG. 42 is a perspective view showing an optical mounting board in a seventeenth embodiment of the hybrid optical integrated circuit of the present invention.

43 is a cross-sectional view taken along the plane CC ′ of FIG. 42.

FIG. 44 is a view showing an eighteenth embodiment of the hybrid integrated circuit of the present invention, (A) being a perspective view and (B) being a perspective view.
FIG. 7A is a sectional view taken along line BB ′ in FIG.

FIG. 45 is a view showing a nineteenth embodiment of the hybrid integrated circuit of the present invention, (A) being a perspective view and (B) being a perspective view.
FIG. 7A is a sectional view taken along line BB ′ in FIG.

46 is a perspective view showing a method of fixing the optical function element of the hybrid integrated circuit of FIG. 45 to a subcarrier.

FIG. 47 is a perspective view showing an optical mounting board in a twentieth embodiment of the hybrid optical integrated circuit of the present invention.

48 is a cross-sectional view taken along the DD ′ plane of FIG. 47.

FIG. 49 is a perspective view showing an optical mounting board in a twenty-first embodiment of the hybrid optical integrated circuit of the present invention.

50 is a cross-sectional view showing a state where a substrate or the like of the hybrid optical integrated circuit of FIG. 49 is warped.

FIG. 51 is a perspective view showing the configuration of an optical mounting board in a twenty second embodiment of the hybrid optical integrated circuit of the present invention.

52 is a perspective view showing a twenty second embodiment of the hybrid optical integrated circuit of the present invention. FIG.

53 is a cross-sectional view taken along the line III-III ′ in FIG.

54 is a cross-sectional view showing a state after reflow of the solder bumps in the hybrid optical integrated circuit of FIG. 53.

FIG. 55 is a schematic perspective view showing the structure of an optical mounting board in a twenty-third embodiment of the hybrid optical integrated circuit of the present invention.

56 is a perspective view showing a substrate structure when an alumina substrate having a flat surface is used as a substrate of the hybrid optical integrated circuit of FIG. 55 and a quartz optical waveguide is used as an optical waveguide.

FIG. 57 is a plan view showing a twenty-fifth embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 58 is an enlarged schematic perspective view of the main part shown in FIG. 57.

FIG. 59 is a plan view showing the configuration of a twenty-sixth embodiment of the hybrid integrated circuit of the present invention.

60 is a cross-sectional view of the circuit shown in FIG. 59,
(A) is a cross-sectional view taken along line Xa-Xa 'showing an LD mounting form, and (B) is a sectional view showing a modulation array mounting form Xb-.
It is sectional drawing which follows the Xb 'line.

FIG. 61 is a plan view showing the configuration of the twenty-seventh embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 62 is a plan view of a twenty-eighth embodiment of the hybrid optical integrated circuit of the present invention.

63 is a view for explaining an alignment method of the optical functional element to be fixed on the circuit shown in FIG. 62,
(A) is a plan view showing alignment fixing of the LD array,
FIG. 6B is a plan view showing centering and fixing of the modulator array.

FIG. 64 is a plan view showing a twenty ninth embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 65 is a plan view showing a 30th embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 66 is a perspective view showing a structure of an optical element and a carrier in the structure of the first embodiment of the optical submodule mountable on the hybrid optical integrated circuit of the present invention.

67 is a cross-sectional view taken along the line AA ′ of FIG. 66.

FIG. 68 is a cross-sectional view showing a second embodiment of an optical submodule mountable on the hybrid optical integrated circuit of the present invention.

FIG. 69 is a cross-sectional view showing a third embodiment of the optical sub-module that can be mounted on the hybrid optical integrated circuit of the present invention.

70 is an exploded perspective view showing the configuration of a thirty-fourth embodiment of the hybrid optical integrated circuit of the present invention which uses the optical sub-module shown in FIGS. 66 and 67. FIG.

71 is a sectional view taken along the line BB ′ of FIG. 70.

72 is a cross-sectional view taken along the line CC ′ of FIG. 70.

FIG. 73 is a perspective view showing the configuration of a fourth embodiment of an optical submodule which can be mounted on the 35th embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 74 is a sectional view showing the structure of the thirty-sixth embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 75 is an exploded perspective view showing the structure of an optical sub-module according to a fifth embodiment which can be mounted on the thirty-seventh embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 76 is an exploded perspective view showing the structure of the 38th embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 77 is a perspective view showing the configuration of an optical sub-module according to a sixth embodiment which can be mounted on the thirty-ninth embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 78 is a perspective view showing a configuration of a seventh embodiment of an optical submodule which can be mounted on the 40th embodiment of the hybrid optical integrated circuit of the present invention.

FIG. 79 is an exploded perspective view showing the configuration of an eighth embodiment of the optical sub-module which can be mounted on the 41st embodiment of the hybrid optical integrated circuit of the present invention.

80 is a sectional view taken along the line DD ′ in FIG. 79.

81 is a perspective view showing the configuration of the forty-second embodiment of the hybrid optical integrated circuit of the present invention. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Si substrate 2 Guide groove 3a, 3b, 3c Positioning reference plane 4 Optical fiber 5 Semiconductor laser (LD) 6 Electrical wiring 7 Quartz optical waveguide 8 Semiconductor optical element 10 Quartz optical waveguide 11 Element positioning reference plane 12 Buffer layer 13 Quartz-based optical waveguide 14 Element holding base 15 Semiconductor laser W Gold wire 16 Electric wiring base 17 Heat sink 18 Optical waveguide 19 Optical fiber guide 20 Optical element guide 21 Electric wiring support base 22 First conductive film (common electrode) 23 Second Conductive film 24 Optical fiber 25 Laser diode 26 Optical waveguide 27 Optical semiconductor element 28 Electrical wiring part 30 Si terrace for mounting optical element 31 Optical fiber 33 Dielectric layer 35 Si terrace for electronic circuit 37 Optical functional element (LD) 38 Electronic circuit 40 Quartz optical waveguide 41 Under clad 42 Core 43 Over Clad 44 Subcarrier 50 Dielectric layer 51 Conductor pattern for electronic circuit 510 Conductor pattern 52 Thin film electrode 53 Solder bump 60 Embedded optical waveguide 61 Coplanar line 62 Optical element 63 Mounting part 64 Gold ribbon wire 65a, 65b Guide post 66 Solder Pattern 67 Si subcarrier 68 Optical element mounting part 69 Conductive adhesive

 ─────────────────────────────────────────────────── ─── Continuation of front page (31) Priority claim number Japanese Patent Application No. 6-148222 (32) Priority date Hei 6 (1994) June 29 (33) Priority claim country Japan (JP) (72) Inventor Kaoru Yoshino 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Inventor Kuniharu Kato 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Inventor Kazuyuki Moriwaki 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Akio Sugita 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Inventor Ikuo Ogawa 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Masahiro Yanagisawa 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Japan Telegraph and Telephone Stock Association The inner (72) inventor Toshikazu Hashimoto, Chiyoda-ku, Tokyo Uchisaiwaicho 1 chome No. 6 Date. This Telegraph and Telephone in the Corporation

Claims (36)

[Claims] 1. A mounting board including an optical waveguide section, an optical element mounting section, and an electric wiring section provided on the same substrate, wherein the optical element mounting section is composed of a terrace provided in a convex shape on the substrate. An optical / electronic hybrid mounting substrate, wherein the electric wiring portion is composed of a dielectric layer formed on the substrate and a conductor pattern formed on the surface or inside thereof. 2. The optical / electronic hybrid mounting board according to claim 1, wherein the terrace is made of Si. 3. The optical / electronic hybrid mounting substrate according to claim 2, wherein the substrate is Si for mounting the optical element.
A platform characterized by having a Si terrace for forming an electronic circuit in addition to the terrace. 4. The optical / electronic hybrid mounting substrate according to claim 2, wherein the height of the upper surface of the conductor pattern on the dielectric layer is S near at least the Si terrace of the optical element mounting portion and the electric wiring portion.
An optical / electronic hybrid mounting substrate, which is set to be lower than the upper surface of the i-terrace. 5. The optical / electronic hybrid mounting substrate according to claim 4, wherein the Si terrace has side surfaces having an inclination angle, and thin film electrodes are formed on the Si terrace surface and side surfaces. Is an optical / electronic hybrid mounting substrate, which is electrically connected to a conductor pattern formed on the upper surface or inside the dielectric layer around the Si terrace. 6. The optical / electronic hybrid mounting board according to claim 4, wherein the Si terrace for an optical element is divided into two or more,
A space between the divided Si terraces is filled with the dielectric layer, and a conductor pattern is provided on the dielectric layer between the Si terraces for the optical element. . 7. The optical / electronic hybrid mounting board according to claim 1, wherein the optical waveguide portion has a positioning groove formed on the Si terrace, and a light fixed in the positioning groove. An optical / electronic hybrid mounting substrate comprising a fiber. 8. The optical / electronic hybrid mounting substrate according to claim 1, wherein the optical waveguide section includes an under-cladding layer, a core and an over-cladding layer formed on the substrate. The optical / electronic hybrid mounting substrate is characterized in that the height of the bottom surface of the core of the optical waveguide is set to be higher than the upper surface of the Si terrace. 9. The optical / electronic hybrid mounting board according to claim 7, wherein the optical waveguide includes one or more signal optical waveguides and one or more monitor optical waveguides. The Si terrace for light is provided at a position corresponding to the input / output end of the optical waveguide for monitoring, and the S for optical element is used.
An optical / electronic hybrid mounting substrate having thin-film electrical wiring formed on the surface of the i-terrace. 10. The optical / electronic hybrid mounting substrate according to claim 8, wherein the optical waveguide is a dielectric optical waveguide, and the dielectric layer of the electric wiring portion is an underclad layer of the dielectric optical waveguide. An optical / electronic hybrid mounting substrate characterized in that 11. The optical / electronic hybrid mounting substrate according to claim 10, wherein a part of the first dielectric layer formed of the underclad layer of the optical waveguide is made of a material different from that of the optical waveguide. An optical / electronic hybrid mounting board, wherein two dielectric layers are laminated, and a conductor pattern is formed inside or on the surface of the second dielectric layer. 12. The optical / electronic hybrid mounting substrate according to claim 10, wherein the substrate is a Si substrate, and the optical waveguide and the electric wiring portion dielectric layer are both formed of a silica optical waveguide. A conductor pattern formed on a dielectric layer of an electric wiring portion is a coplanar wiring composed of a central conductor and a ground conductor, and the thickness of the dielectric layer is 50 μm or more. 13. The optical / electronic hybrid mounting substrate according to claim 10, wherein the Si substrate has a specific resistance of 50 Ωcm or more on average, and the optical waveguide and the dielectric layer are mainly silica-based waveguides. The conductor pattern formed and provided on the dielectric layer of the electric wiring portion is a coplanar wiring including a center conductor and a ground conductor, and the thickness of the dielectric layer is 20 μm or more. Electronic hybrid mounting board. 14. A silica-based optical waveguide comprising an under-clad, a core and an over-clad formed on a Si substrate, and a silica-based optical waveguide centered on one of the over-clad and the under-clad of the silica-based optical waveguide. In an optical / electronic hybrid mounting substrate including an electric wiring layer having a coplanar wiring composed of a conductor and a ground conductor, a quartz optical waveguide having a thickness of 50 μm or more is provided between the electric wiring layer and the Si substrate. An optical / electronic hybrid mounting board characterized by: 15. A silica-based optical waveguide comprising an under-clad, a core and an over-clad formed on a Si substrate, and a center which is deposited on either one of the over-clad and the under-clad of the silica-based optical waveguide. In an optical / electronic hybrid mounting substrate including an electric wiring layer having a coplanar wiring made of a conductor and a ground conductor, the resistivity of the Si substrate is 50 Ωcm or more on average, and the electric wiring layer and the Si substrate are The optical characteristic is that a silica optical waveguide having a thickness of 20 μm or more is used.
Electronic hybrid mounting board. 16. The optical / electronic hybrid mounting board according to claim 11, wherein the silica-based optical waveguide has a total thickness of 120 μm or less. substrate. 17. The optical / electronic hybrid mounting substrate according to claim 8, wherein the substrate is a Si substrate having a concave portion and a convex portion formed on the surface, and the Si substrate convex portion is The optical waveguide functioning as the Si terrace, the optical waveguide is an optical waveguide including an under-cladding layer, a core, and an over-cladding formed in the Si substrate recess, and the electric wiring portion is a dielectric layer formed on the Si substrate recess. And an optical / electronic hybrid mounting substrate comprising a conductor pattern provided on the surface or inside thereof. 18. The optical / electronic hybrid mounting substrate according to claim 1, wherein a conductor pattern is formed inside the substrate, and the conductor pattern and the dielectric layer inside the substrate. Optical / characterized by being electrically connected to the conductor pattern on the inside or on the top surface
Electronic hybrid mounting board. 19. The optical / electronic hybrid mounting substrate according to claim 1, wherein the optical waveguide portion is an optical waveguide including an under-cladding layer, a core and an over-cladding layer formed on the substrate, and the core of the optical waveguide. The height of the bottom surface is set to be higher than the upper surface of the Si terrace, and the conductor pattern of the electric wiring portion has a height substantially equal to the surface of the optical waveguide overclad surface of the dielectric layer. An optical / electronic hybrid mounting board, characterized in that it is provided in. 20. A step of providing a convex Si terrace on a substrate, and after forming an optical waveguide under-cladding layer on the substrate,
A step of flattening the surface, a step of forming a core pattern and an overclad layer, and a step of removing the overclad layer of the Si terrace part and the electric wiring part, all of the core and part of the lower clad layer to form an element mounting part. By doing so, a step of exposing the upper surface of the Si terrace and setting the surface of the undercladding layer in the electric wiring portion region lower than the Si terrace surface by a desired dimension, and a step of forming a conductor pattern on the electric wiring portion are performed. A method of manufacturing an optical / electronic hybrid mounting board, comprising: 21. An optical waveguide including an under-cladding layer, a core and an over-cladding layer provided on a substrate, and a Si terrace functioning as an element mounting portion provided in a convex shape on the substrate adjacent to the optical waveguide. The optical device Si terrace is formed on a mounting substrate that is formed adjacent to the Si terrace on the substrate and that includes an electric wiring portion including a dielectric layer and a conductor pattern provided on the surface or inside of the dielectric layer. Above, while maintaining the optical coupling with the optical waveguide, with the optical element surface facing downward and at least a part of the optical element surface being in contact with the Si terrace upper surface, and
An optical / electronic hybrid integrated circuit in which an optical functional element is mounted while maintaining electrical contact with the conductor pattern of the electric wiring portion. 22. An optical waveguide including an under-cladding layer, a core and an over-cladding layer provided on a substrate, and an optical element functioning as an optical element mounting portion provided on the substrate in a convex shape adjacent to the optical waveguide. Formed on the substrate adjacent to the Si terrace for optical element and the Si terrace for optical element,
An electric wiring portion composed of a dielectric layer and a conductor pattern provided on the surface or inside thereof, and an electronic circuit Si terrace functioning as an electronic circuit mounting portion provided in a convex shape on the substrate in the electric wiring portion region. On the mounted substrate, and on the Si terrace for the optical element, the optical waveguide is optically coupled to the optical waveguide with the optical element surface facing downward and at least a part of the optical element surface being in contact with the upper surface of the Si terrace. And
An optical functional element is mounted while maintaining electrical contact with the conductor pattern of the electric wiring portion, and an electronic circuit is mounted on the Si terrace for electronic circuit while maintaining thermal connection with the Si terrace. An optical / electronic hybrid integrated circuit characterized in that 23. The optical / electronic hybrid integrated circuit according to claim 22, wherein the height of the upper surface of the conductor pattern on the dielectric layer near the Si terrace for electronic circuits is set lower than the upper surface of the Si terrace for electronic circuits. , Part of the electronic circuit is Si for electronic circuit
The electrode is held in contact with the terrace, and at least a part of the electrode on the surface of the electronic circuit maintains an electrical connection with a conductor pattern on the dielectric layer corresponding to the electrode via a conductive bonding material. An optical / electronic hybrid integrated circuit characterized by being fixed while being fixed. 24. The optical / electronic hybrid integrated circuit according to any one of claims 21 to 23, wherein the optical functional element is provided with irregularities on its surface and is electrically connected from the concave surface to the convex surface. The back electrode of the optical functional element is contacted and fixed on the concave portion of the subcarrier made of a heat conductive material provided with the conductor pattern in the above-mentioned state in a state of being electrically connected to the conductor pattern, and the Si terrace is 2 The dielectric layer is divided into two or more, and the space between the divided Si terraces is filled with the dielectric layer, and the electrode provided on the surface of the active layer side of the optical functional element on the dielectric layer around the Si terrace. Are provided and a second conductor pattern corresponding to the optical function element back surface electrode is provided, and the heights of the upper surfaces of the first and second conductor patterns are set lower than that of the Si terrace upper surface. Yes The sub-carrier optical functional element fixed to the periphery the Si of the light element surface while the device surface facing down
It is mounted on a mounting substrate while maintaining contact and thermal connection with the terrace surface, and the optical functional element surface electrode and the first conductor pattern are electrically connected via a conductive bonding material. The optical / electronic hybrid integrated circuit, wherein the back electrode of the optical functional element is in electrical contact with the second conductor pattern via the conductor pattern on the convex portion of the subcarrier and the conductive bonding material. 25. The optical / electronic hybrid integrated circuit according to any one of claims 21 to 23, wherein the optical functional element is provided with irregularities on its surface and is electrically connected from the concave surface to the convex surface. The back electrode of the optical functional element is contacted and fixed in a state of being electrically connected to the conductor pattern on the concave portion of the sub-carrier made of a heat conductive material provided with the conductor pattern of the above-mentioned state. It is divided into the above and has a side surface having an inclination angle, the periphery of the divided Si terrace is filled with the dielectric layer, and the optical function is provided on the dielectric layer around the Si terrace. A first conductor pattern corresponding to the electrode provided on the surface of the active layer side of the device is provided, and the height of the upper surface of the first conductor pattern is set lower than that of the Si terrace upper surface. Terrace top And a thin film electrode corresponding to the back electrode of the optical functional element is formed on a part of the inclined side surface, and the thin film electrode is electrically connected to the second conductor pattern provided on the dielectric. The optical functional element fixed to the optical element is fixed to the peripheral portion of the optical element surface with the element surface facing downward.
It is mounted on a mounting substrate while maintaining contact and thermal connection with the terrace surface, and the optical functional element surface electrode and the first conductor pattern are electrically connected via a conductive bonding material. The back electrode of the optical functional element is, via the conductor pattern on the subcarrier convex portion and the thin film electrode on the Si terrace,
An optical / electronic hybrid integrated circuit, which is in electrical contact with a second conductor pattern. 26. The optical / electronic hybrid integrated circuit according to claim 24, wherein in the optical functional element fixed to the subcarrier, the distance from the outer surface of the subcarrier to the active layer of the optical functional element is desired. The guide structure made of the optical waveguide material is provided near the Si terrace in the vicinity of the Si terrace, and the distance from the inner surface of the guide structure to the center of the optical waveguide core is The optical functional element is set to have a set value D, and the optical functional element is mounted on the Si terrace while keeping the outer surface of the subcarrier in contact with the inner surface of the guide structure. Electronic hybrid integrated circuit. 27. The optical / electronic hybrid integrated circuit according to any one of claims 21 to 25, wherein the optical waveguide comprises one or more signal line optical waveguides and one or more monitor optical waveguides. The optical functional element has a signal port and a monitor port formed at positions corresponding to the signal optical waveguide and the monitor optical waveguide on the mounting board, respectively. And the monitor port of the optical function element are optically coupled, and at the same time, the optical function element is installed on the Si terrace on the mounting substrate in a state where the signal optical waveguide and the signal port are optically coupled. An optical / electronic hybrid integrated circuit characterized by: 28. An optical waveguide portion formed on a substrate and having at least one signal optical waveguide and at least one monitor optical waveguide, and an end portion of the optical waveguide portion or the optical waveguide portion. An optical element mounting portion provided in a void provided in the middle of the optical waveguide, a signal port and a monitor port for optically coupling to the signal optical waveguide and the monitor optical waveguide provided in the optical waveguide portion. A monitor optical waveguide of the optical waveguide portion and a monitor port of the optical functional element are optically coupled, and at the same time, a signal optical waveguide of the optical waveguide portion and a signal port of the optical functional element are optically coupled. The optical / electronic hybrid integrated circuit, wherein the optical functional element is mounted on the optical element mounting portion in the above state. 29. The optical / electronic hybrid integrated circuit according to claim 25, wherein the other waveguide end of each of the monitor optical waveguides optically coupled to the monitor port is connected to the optical / electronic hybrid mounting board end portion. An optical / electronic hybrid integrated circuit characterized by being guided. 30. The optical / electronic hybrid integrated circuit according to claim 25, wherein two or more optical functional elements are mounted in tandem on the optical / electronic hybrid mounting substrate, and a monitor of each optical functional element is provided. An optical waveguide for monitoring that connects the optical functional element monitor port and the end of the optical / electronic hybrid mounting board or an optical waveguide for monitoring that connects two or more optical functional elements is optically coupled to the port. An optical / electronic hybrid integrated circuit characterized by: 31. The optical / electronic hybrid integrated circuit according to claim 25, wherein the optical functional element mounted on the optical / electronic hybrid mounting substrate has two or more monitor ports, and / The electronic mounting board has a number of monitor optical waveguides corresponding to the monitor ports, and at least one of these monitor ports is set to have a width wider than the signal port width. An optical / electronic hybrid integrated circuit, wherein at least one of the signal optical waveguides is set to have a width wider than that of the signal optical waveguide. 32. An optical functional element having an optical element height reference surface at a predetermined distance from the active layer, an optical element holding surface for holding the optical functional element, and a predetermined distance from the optical element holding surface. An optical sub-module comprising a carrier having a certain carrier height reference plane and carrier electrical wiring, wherein an optical element height reference plane of the optical functional element and an optical element holding surface of the carrier are fixed in contact with each other. In addition, the optical sub-module, wherein the active layer side electrode portion of the optical function element and the carrier electric wiring are electrically connected. 33. The optical sub-module according to claim 32, wherein the carrier is formed of a substrate having irregularities and a dielectric layer formed on the concave portion of the substrate, and the optical element holding surface and the carrier height reference surface are An optical sub-module, characterized in that it is formed by a convex portion of a substrate, and the carrier electric wiring is formed in a dielectric layer. 34. The optical sub-module according to claim 32, wherein the dielectric layer constituting the carrier is a film-like material having an electric wiring layer formed on the surface and inside thereof. 35. The optical sub-module according to claim 32, wherein the carrier electric wiring is formed on the surface and inside of the carrier. 36. An under clad provided on a substrate,
A mounting substrate comprising an optical waveguide including a core and an overclad, a Si terrace, a dielectric layer and a conductor pattern provided inside or on the surface of the dielectric layer, the thickness of the dielectric layer being the conductor pattern. The optical element holding surface for holding the optical element on the optical / electronic hybrid mounting substrate which is set so that the height of the optical element is approximately equal to the surface of the optical waveguide overclad, and a predetermined distance from the optical element holding surface. A carrier having a carrier height reference plane and a carrier electric wiring at a distance of, and an optical functional element held on the optical element holding surface, from the optical functional element active layer to the carrier height reference plane Is set to be approximately equal to the step between the optical waveguide core and the upper surface of the Si terrace, and the electrical electrical connection between the carrier electric wiring and the active layer side electrode of the optical functional element is achieved. Submo Joule is in contact with the Si terrace of the optical / electronic hybrid mounting board and the carrier height reference plane of the optical element sub-module, and the conductor pattern on the dielectric layer surface of the optical / electronic hybrid mounting board and the optical pattern. An optical / electronic hybrid integrated circuit, which is mounted in a state of being electrically connected to a carrier electric wiring of a sub-module.