JP6423161B2 - Optical integrated circuit device - Google Patents

Description

  The present invention relates to an optical integrated circuit device, and more particularly to an optical integrated circuit device on which an edge emitting semiconductor laser is mounted.

  In recent years, with the expansion of the scale of data centers, it has become an important issue to improve the communication speed between server racks and between server boards. The optical interconnect technology is a technology for performing such relatively short distance communication by optical fiber communication. Since signal degradation due to optical fiber is small compared to electrical transmission lines, the expandability of distance and communication speed is high compared to telecommunications, and the use in data centers is expanding. The main devices of optical interconnect technology are optical transmitter and optical receiver. Since they are both mounted on or directly mounted on a server board that is required to be small in size and high in density, they are required to be sufficiently small in size and low in power consumption. In particular, an optical transmitter needs to be equipped with a light source in addition to a modulator, and miniaturization including this is one of the technical problems.

  In many cases, the light source used in the optical transmitter is a minute semiconductor laser having a size of 1 mm square or less. There are two types of semiconductor lasers, an edge emission type and a surface emission type. There are also multiple means to incorporate a light source into an optical transmitter. A semiconductor laser is directly integrated into an optical integrated circuit chip equipped with an optical transmission function, or an optical integrated circuit chip and a laser chip are separated into separate small substrates (submount, interposer, etc.) The laser chip is mounted side by side or mounted on the optical integrated circuit chip. Such semiconductor lasers and their integration / mounting methods are selected and combined according to the purpose. For example, it is a promising combination to mount a high-output, high-stable edge-emitting semiconductor laser on an optical integrated circuit chip in which a high-speed modulator is integrated. Although it is an advantage that the performance of the modulator and the semiconductor laser can be improved separately, a technique for mounting the semiconductor laser on the optical integrated circuit chip with high accuracy and at low cost is required.

  Conventionally, various mounting structures for mounting an edge emitting semiconductor laser on an optical integrated circuit chip have been proposed (see, for example, Patent Documents 1-6). These are mounting structures of an edge emitting semiconductor laser when the optical integrated circuit chip is an oxide film waveguide formed on a glass substrate, that is, a PLC (Planar Lightwave Circuit). In the structure of the edge emitting semiconductor laser, an active layer is provided near the surface of the laser chip, a cladding layer is provided on the active layer (further, on the surface side), and an active layer side electrode (first element electrode) is provided thereon. Is formed. When the surface having the active layer is defined as the front surface, a back electrode (second element electrode) is formed on the back surface of the laser. In any of the mounting structures according to the prior art described above, the semiconductor laser is mounted with the active layer side surface of the laser facing the optical integrated circuit chip side. Laser mounting is performed so that the end face of the core of the waveguide formed in the optical integrated circuit chip or the end face of the core of the optical coupling structure formed at the end of the waveguide and the end face of the active layer of the laser abut each other. Done. The active layer side electrode of the laser is crimped or soldered to the receiving side electrode formed on the optical integrated circuit chip simultaneously with the mounting of the laser. Since the active layer side electrode of the laser comes below (deep position) from the waveguide on the optical integrated circuit chip, the receiving side electrode on the optical integrated circuit chip is also formed at a position deeper than the waveguide. Usually, since the thickness of the clad layer on the active layer of the semiconductor laser is several μm, the receiving electrode is located at a position several μm or more deeper than the waveguide on the optical integrated circuit chip. As described above, in the conventional mounting structure on the PLC, mounting of the edge emitting semiconductor laser is realized by providing the receiving side electrode at a position deeper than the core of the waveguide on the optical integrated circuit chip.

  In the PLC, a waveguide optical circuit having an oxide film as a core is formed on a glass substrate, but in recent years, an optical waveguide circuit is also formed on an SOI (Silicon On Insulator) substrate. I came. The structure of the SOI substrate includes a silicon substrate, a buried silicon oxide (BOX) layer on the silicon substrate, and a surface silicon layer thereon. Since the refractive index of silicon is higher than the refractive index of BOX, if BOX is used as the lower cladding, the surface silicon layer is processed into a waveguide core, and a silicon oxide film or the like is deposited thereon to form the upper layer. A circuit of an optical waveguide (silicon waveguide) having silicon as a core can be formed simply by using the cladding. An optical waveguide with a silicon core has a smaller bend radius than an optical waveguide with an oxide film and can be bent without causing optical loss, enabling high integration of optical circuits. There was a problem that high machining accuracy was required to obtain the street performance. However, an optical integrated circuit using an SOI substrate has been put into practical use because a technologically mature CMOS (Complementary Metal-Oxide-Semiconductor) production line can be used and the processing accuracy in that line has been sufficiently improved in recent years. It has come to be.

  A semiconductor laser can be mounted on an optical integrated circuit (SOI optical integrated circuit) on an SOI substrate in the same manner as a conventional mounting structure on a PLC. In that case, a specific formation process is as follows, for example. First, the cladding oxide film is processed by dry etching to form an end surface for laser coupling in the silicon waveguide. At this time, the BOX layer of the lower cladding is etched, and the surface of the silicon substrate under the BOX layer appears. If necessary, the entire surface is further etched to adjust the height of the surface. Subsequently, the silicon surface is further etched while leaving a part to form a pedestal (terrace) for supporting the laser chip. Finally, a receiving electrode is formed on the bottom surface of the silicon at a place other than the base. As described above, even in the conventional mounting structure using the SOI substrate, the receiving-side electrode is provided at a position deeper than the core of the waveguide on the optical integrated circuit chip, thereby realizing the mounting of the edge emitting semiconductor laser. It was.

Japanese Patent No. 2823044 JP 2000-137148 A Japanese Patent No. 3698601 Japanese Patent No. 4798884 JP 2007-298770 A Japanese Patent No. 5186785

  As described above, an optical integrated circuit using an SOI substrate is often manufactured using a CMOS line, which means that an SOI optical integrated circuit is manufactured within a CMOS process. However, the conventional process for forming the semiconductor laser mounting portion deviates from the range of a general CMOS process. For example, the step that can be formed on the waveguide end face may be about 4 to 6 μm including the upper clad, silicon core, lower clad, and pedestal height. Does not include processes on stepped substrates. Therefore, there is a problem that the receiving electrode cannot be formed after the end face is formed simply by bringing it into the CMOS line.

  In a conventional process for forming a semiconductor laser mounting structure in a PLC, a resist pattern thicker than a step on a substrate surface is formed using a high-viscosity photoresist, and a receiving electrode is formed by using a lift-off process. A similar process can be applied to the case where a laser mounting structure is formed on an SOI optical integrated circuit, but it uses a wafer having a small diameter similar to that used in a PLC, that is, a wafer (substrate) having a diameter of 125 to 150 mm. Limited to cases. Even if a photoresist thick film coating or lift-off process is performed on a wafer having a diameter of 200 mm or 300 mm, which has a high mass production effect, it is difficult to obtain a high yield on the entire surface of the wafer. Therefore, the conventional technique alone has a problem that the diameter of the wafer does not increase and the manufacturing cost cannot be reduced.

  In the description so far, the conventional problems related to the mounting structure of the end face coupled semiconductor laser in the optical integrated circuit device have been described. However, the same problem has occurred in the end face coupled type semiconductor device instead of the semiconductor laser. This also occurs when another optical element such as a semiconductor amplifier or a light receiving element is mounted.

  The present invention has been made in view of the above-mentioned problems, and one of the problems is that a semiconductor laser or the like is provided without providing a receiving electrode on the substrate surface (wafer surface) at a position lower than the optical waveguide core. It is an object to provide an optical integrated circuit device on which the optical element is mounted.

  In order to solve the above-described problems, an embodiment of the present invention includes a substrate, an optical waveguide formed on the substrate and having an optical coupling end surface perpendicular or substantially perpendicular to the substrate, and the optical waveguide on the substrate. One or a plurality of first electrical wirings formed at a position higher than the core of the optical element, and an optical element having a light incident / exit end surface on a side surface and a first element electrode on a lower surface, the optical element comprising: The optical integrated circuit device is characterized in that the light incident / exit end face is close to the optical coupling end face of the optical waveguide and the first element electrode is in contact with the first electric wiring.

  According to another aspect of the present invention, in the above aspect, the optical element is configured such that the light incident / exit end face is close to the substrate and the end face opposite to the light incident / exit end face is far from the substrate. The optical integrated circuit device is arranged to be inclined with respect to the substrate.

  According to another aspect of the present invention, in the above aspect, the lower surface of the optical element is supported by at least the surface of the substrate and the first electric wiring, so that the optical element is attached to the substrate. It is an optical integrated circuit device characterized by being inclined at an angle.

  According to another aspect of the invention, the lower surface of the optical element is supported by at least the surface of the substrate and a corner of the protective film of the first electrical wiring, so that the optical element is attached to the substrate. An optical integrated circuit device is arranged to be inclined with respect to the optical integrated circuit device.

  Another aspect of the present invention is an optical integrated circuit device according to the above aspect, wherein when there are a plurality of the first electrical wirings, they belong to a plurality of different wiring layers.

  According to another aspect of the present invention, in the above aspect, the first element electrode of the optical element is bonded to the first electric wiring by a conductive bonding body, whereby the lower surface of the optical element is formed. Is supported by the first electrical wiring. An optical integrated circuit device, wherein:

  According to another aspect of the present invention, in the above aspect, a concave portion is formed in a portion of the surface of the substrate that is in contact with the optical element, and the optical element has a portion in the vicinity of the light incident / exit end surface. The optical integrated circuit device is housed in a recess.

  According to another aspect of the present invention, in the above aspect, the concave portion includes a cutout portion that accommodates the first element electrode and does not contact the first element electrode. Circuit device.

  According to another aspect of the present invention, in the above aspect, the corner of the protective film includes a cutout portion that houses the first element electrode and does not contact the first element electrode. This is an optical integrated circuit device.

  Another aspect of the present invention is the optical integrated circuit device according to the above aspect, wherein the optical coupling end face is inclined so that an upper part thereof protrudes.

  According to another aspect of the present invention, in the above aspect, the light incident / exit end surface of the optical element is formed at a position protruding from the lower surface where the first element electrode is formed. In the optical integrated circuit device, the lower surface of the element is supported by the first electric wiring from both sides or at least one of the light incident / exit end surfaces.

  According to another aspect of the present invention, in the above aspect, the light incident / exit end surface of the optical element is formed at a position protruding from the lower surface where the first element electrode is formed. In the optical integrated circuit device, the lower surface of the element is supported from both sides or at least one of the light incident / exit end surfaces by a protective film surface located above the first electric wiring.

  According to another aspect of the present invention, in the above aspect, the second element electrode on the upper surface of the optical element, a cap that covers the optical element and has an edge fixed on the substrate, and the substrate One or a plurality of second electrical wirings formed at a position higher than the optical waveguide, and the cap is distributed continuously from at least a part of the back surface to the edge. A cap electrode, wherein the cap electrode and the second element electrode are connected by a conductor, and at least a part of the portion distributed on the edge of the first cap electrode is in contact with the second electrical wiring. An optical integrated circuit device.

  Another embodiment of the present invention is the optical integrated circuit device according to the above embodiment, wherein the cap is made of glass or Si.

  According to another aspect of the present invention, in the above aspect, the cap has one or a plurality of second cap electrodes on a surface thereof, the first cap electrode and the first cap electrode penetrating the cap. An optical integrated circuit device comprising one or a plurality of through vias that electrically connect two cap electrodes.

  According to the present invention, it is not necessary to provide a receiving electrode at a position deeper than the core of the waveguide in order to provide an optical integrated circuit device on which an optical element such as a semiconductor laser is mounted. Further, the wire bonding process can be omitted. As a result, an optical integrated circuit chip for a highly integrated transmitter can be manufactured with high productivity using a general CMOS line. Furthermore, the heat dissipation effect of the optical element is increased, and the operation efficiency and reliability of the optical element are improved.

1 is a cross-sectional configuration diagram of an optical integrated circuit device 100 according to a first embodiment of the present invention. It is a section lineblock diagram of optical integrated circuit device 200 concerning a 2nd embodiment of the present invention. It is a cross-sectional block diagram of the optical integrated circuit device 300 which concerns on 3rd Embodiment of this invention. It is a section lineblock diagram of optical integrated circuit device 400 concerning a 4th embodiment of the present invention. It is a section lineblock diagram of optical integrated circuit device 500 concerning a 5th embodiment of the present invention. It is a section lineblock diagram of optical integrated circuit device 600 concerning a 6th embodiment of the present invention. It is a cross-sectional block diagram of the optical integrated circuit device 700 which concerns on 7th Embodiment of this invention. It is a figure for demonstrating the mounting method of the optical integrated circuit device 100 in 1st Embodiment. It is a figure for demonstrating the mounting method of the optical integrated circuit device 100 in 1st Embodiment. It is a figure for demonstrating the mounting method of the optical integrated circuit device 100 in 1st Embodiment. It is a section lineblock diagram of the optical integrated circuit device concerning the modification of a 2nd embodiment. It is a cross-sectional block diagram of the optical integrated circuit device which concerns on the modification of 5th Embodiment. It is a section lineblock diagram of the optical integrated circuit device concerning the modification of a 6th embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is a cross-sectional configuration diagram of an optical integrated circuit device 100 according to the first embodiment of the present invention. In FIG. 1, the optical axis of the optical waveguide core 106 is the Y axis, the normal line of the substrate 102 is the Z axis, and the Y axis and the axis perpendicular to the Z axis are the X axis. A substrate 102, an optical waveguide core 106 formed on the substrate 102, and a semiconductor laser (optical element) 110 mounted on the substrate 102 are provided.

  The optical integrated circuit device 100 is a device manufactured using an SOI substrate including a silicon substrate, a BOX layer, and an SOI layer. The substrate 102 is a silicon (Si) substrate. A BOX layer (buried oxide film layer) 104 is formed on the substrate 102. The BOX layer 104 functions as a lower cladding layer. On the BOX layer 104, an optical waveguide core 106 obtained by processing an SOI layer (silicon layer) is formed. An oxide film 108 as an upper clad layer is formed on the optical waveguide core 106.

  The optical waveguide core 106 has an optical coupling end face 1062 for optically coupling with the semiconductor laser 110. The end faces of the BOX layer 104, the optical waveguide core 106, and the oxide film 108 are continuously processed perpendicularly to the substrate 102, and the optical coupling end face 1062 of the optical waveguide core 106 is perpendicular to the substrate 102 or It is almost vertical.

  The semiconductor laser 110 has an active layer 112 that generates laser light. One end of the active layer 112 communicates with a light emitting end surface 1122 that is a part of the side surface of the semiconductor laser 110. The light emitting end face 1122 is an end face from which laser light is emitted. Further, the semiconductor laser 110 has an element electrode 114 (back surface electrode) formed on the upper surface thereof and an element electrode 116 (active layer side electrode) formed on the lower surface thereof. The lower surface of the semiconductor laser 110 is a surface facing the substrate 102. The semiconductor laser 110 generates laser light by being electrically driven through the device electrode 114 on the lower surface and the device electrode 116 on the upper surface.

  A first oxide film 120 and a second oxide film 126 are stacked on the BOX layer 104 of the substrate 102. A first electrical wiring 118 is disposed in the first oxide film 120, and a second electrical wiring 122 and a third electrical wiring 124 are disposed in the second oxide film 126. The first electrical wiring 118 and the second electrical wiring 122 are wirings that are electrically connected to the element electrode 116 on the lower surface of the semiconductor laser 110. The first electrical wiring 118 and the second electrical wiring 122 are disposed at a position where the height from the substrate 102 is higher than that of the optical waveguide core 106. The third electrical wiring 124 is a wiring that is electrically connected to the element electrode 114 (back surface electrode) on the upper surface of the semiconductor laser 110. The third electrical wiring 124 is electrically connected to the device electrode 114 on the upper surface of the semiconductor laser 110 by a gold wire 132.

  The semiconductor laser 110 is optically coupled to the optical coupling end surface 1062 of the optical waveguide core 106 at the light emitting end surface 1122, and the element electrode 116 on the lower surface is electrically connected to the first electric wiring 118 and the second electric wiring 122. Implemented in the state. More specifically, the light emitting end face 1122 of the semiconductor laser 110 is disposed so as to be close to the optical coupling end face 1062 of the optical waveguide core 106. That is, the XYZ position of the light emitting end surface 1122 of the semiconductor laser 110 so that the laser light emitted from the light emitting end surface 1122 of the semiconductor laser 110 is optically coupled to the optical coupling end surface 1062 of the optical waveguide core 106 with the maximum optical coupling efficiency. Is adjusted. Further, the semiconductor electrode is arranged such that the element electrode 116 on the lower surface of the semiconductor laser 110 is in contact with the first electric wiring 118 on the upper surface side of the first electric wiring 118 and is in contact with the second electric wiring 122 on the upper surface side of the second electric wiring 122. A laser 110 is arranged. The element electrode 116 on the lower surface of the semiconductor laser 110 may be bonded to the first electric wiring 118 and the second electric wiring 122 by solder (conductive bonding agent) 128 and 130. Here, since the first electric wiring 118 and the second electric wiring 122 are disposed at a position where the height from the substrate 102 is higher than the optical waveguide core 106, the semiconductor laser 110 is on the side opposite to the light emitting end face 1122. The end surface 1124 is mounted to be inclined with respect to the substrate 102 so as to be separated from the substrate 102. In other words, the semiconductor laser 110 is mounted with its lower surface supported by the surface of the substrate 102 and the first electric wiring 118 and the second electric wiring 122.

  As described above, the semiconductor laser 110 is disposed to be inclined with respect to the substrate 102, whereby the element electrode 116 on the lower surface of the semiconductor laser 110 is formed at a position where the height from the substrate 102 is higher than that of the optical waveguide core 106. The first electrical wiring 118 and the second electrical wiring 122 can be directly electrically connected. That is, an electrical wiring for electrically connecting to the device electrode 116 on the lower surface of the semiconductor laser 110 is formed on the surface of the substrate 102, or the electrical wiring on the surface of the substrate 102 thus formed is at a position higher than that. The semiconductor laser 110 can be mounted on the substrate 102 without connecting the first electric wiring 118 and the second electric wiring 122 with a gold wire or the like. As a result, the bonding process using a gold wire or the like can be reduced or eliminated completely. In general, the length of the semiconductor laser 110 along the active layer 112 is several hundred microns, and the height of the step between the surface of the substrate 102 and the surface of the second oxide film 126 is several microns. Is 1 ° or less. Therefore, the decrease in the optical coupling efficiency between the semiconductor laser 110 and the optical waveguide core 106 due to the inclination of the semiconductor laser 110 is substantially negligible.

  A recess 1022 may be formed in the vicinity of the optical coupling end face 1062 of the optical waveguide core 106 on the surface of the substrate 102. The semiconductor laser 110 is arranged such that the corner (edge) of the lower surface is accommodated in the recess 1022. That is, the corner of the lower surface of the semiconductor laser 110 is accommodated in the recess 1022 so as not to contact the surface of the substrate 102. Thereby, it is possible to prevent the fragile lower surface corner of the semiconductor laser 110 from being damaged.

  Although the inclination of the semiconductor laser 110 can be changed by adjusting the thickness of the solders 128 and 130, the corner 1040 of the protective film (interlayer film) on the first electric wiring 118 or the protective film on the second electric wiring 122 The corner 1041 and, if necessary, the corner 1050 of the protective film (upper clad) on the optical coupling end face 1062 are in contact with the semiconductor laser 110, the corner 1030 and at least one of the corner 1040 and the corner 1041 Since the semiconductor laser 110 is fixed, the position and inclination of the semiconductor laser 110 on the substrate are determined automatically regardless of the thickness of the solders 128 and 130, and alignment in the Z direction is not necessary. If it is desired to avoid applying a force to the end face of the semiconductor laser 110, the semiconductor laser 110 does not necessarily contact the corner 1050.

  FIG. 8 is an explanatory diagram for explaining a method for obtaining the optical axis position of the semiconductor laser 110. If the dimensions of a, b, and c in FIG. 8 are defined, the optical axis height of the semiconductor laser 110 when the semiconductor laser 110 is mounted can be defined. Even if the thickness b varies somewhat, the error in the height of the output end 1122 of the semiconductor laser 110 is reduced to about (c / a), so that strict management of the pedestal height on which the semiconductor laser 110 is placed is unnecessary. Become.

  When the error in the thickness of the electrode of the semiconductor laser 110 is large, the height reference may be set to the element surface of the semiconductor laser (a place where there is no electrode). FIG. 8 shows how the semiconductor laser 110 is brought into contact with the substrate. That is, in order to prevent the electrode of the semiconductor laser 110 from directly hitting the corners 1030, 1040, or 1041, a portion where the element electrode 116 of the semiconductor laser 110 exists is notched on the substrate side following the recess 1022, The device electrode 116 is accommodated by notching the corners 1040 and 1041.

  9 and 10 are top views of the semiconductor laser and the semiconductor laser mounting portion for explaining the specific structure and mounting method thereof. The upper diagram of FIG. 9 shows the arrangement of the semiconductor laser 2000 and its three active layer side element electrodes 2001, 2002, 2003 when three light emitting portions are arranged in parallel. 9 is a plan view of the vicinity of the semiconductor laser mounting portion, and includes cores 2011, 2012, 2013 of three optical waveguides (or optical couplers), a recess 2021, and a first portion. Electrode wiring electrode pads 2031 and 2032 and second electric wiring electrode pads 2034 are depicted. The recess 2021 includes a notch 2022 for accommodating the protrusions of the device electrodes 2001, 2002, and 2003 of the semiconductor laser 2000. Similarly, the step on the core 2011, 2012, 2013 side of the optical waveguide of the protective film (interlayer film) 1060 on the first electric wiring includes a notch 2023. In this way, as shown in FIG. 10, when the semiconductor laser 2000 is overlapped with the semiconductor laser mounting portion 2050, the device electrodes 2001, 2002, 2003 are accommodated in the notches 2022 and 2003 and do not contact the substrate surface. Even if the thicknesses of these element electrodes deviate from the design values, the mounting height of the semiconductor laser 2000 is not affected.

  In the present embodiment, the electric wiring is described as having a two-layer structure including the first layer of the first electric wiring 118 and the second layer of the second electric wiring 122 and the third electric wiring 124. May have a single-layer structure or a multilayer structure of three or more layers. Further, the tilt angle of the semiconductor laser 110 may be adjusted by the height of the solders 128 and 130 that join the device electrode 116 on the lower surface to the first electric wiring 118 and the second electric wiring 122.

Second Embodiment
FIG. 2 is a cross-sectional configuration diagram of an optical integrated circuit device 200 according to the second embodiment of the present invention. The optical integrated circuit device 200 is different from the optical integrated circuit device 100 shown in FIG. In FIG. 2, the same components as those of the optical integrated circuit device 100 are denoted by the same reference numerals. In FIG. 2, as in FIG. 1, the optical axis of the optical waveguide core 106 is the Y axis, the normal line of the substrate 102 is the Z axis, and the axes perpendicular to the Y axis and the Z axis are the X axis. The optical integrated circuit device 200 includes a substrate 102, an optical waveguide core 106 formed on the substrate 102, and a semiconductor laser (optical element) 210 mounted on the substrate 102. In FIG. Since the axis is a direction perpendicular to the paper surface, the optical waveguide core 106, the BOX layer 104 below the optical waveguide core 106, and the oxide film 108 above the optical waveguide core 106 are not shown.

  The semiconductor laser 210 has an active layer 212 that generates laser light. The active layer 212 is a thin layer parallel to the substrate of the semiconductor laser 210 and is long in a rod shape, and its length direction is the Y direction (direction perpendicular to the paper surface) in the drawing. One end of the active layer 212 communicates with a light emitting end surface 2122 which is a part of a side surface of the semiconductor laser 210. The light emitting end face 2122 is an end face from which laser light is emitted. The semiconductor laser 210 has an element electrode 214 formed on the upper surface and an element electrode 216 formed on the lower surface 218. The semiconductor laser 210 generates a laser beam by being electrically driven through the device electrode 214 on the upper surface and the device electrode 216 on the lower surface.

  The semiconductor laser 210 has a protruding portion 220 protruding from the lower surface 218. The protruding portion 220 is a portion where the active layer 212 is formed. The formation method of the protrusion part 220 is as follows, for example. An etching stop layer is formed in advance on the lower surface 218 portion of the semiconductor laser 210, and the lower surface 218 is exposed by etching both side portions of the protruding portion 220 while leaving the protruding portion 220 portion. By introducing the etching stop layer, the protrusion height of the protrusion 220 can be adjusted more stably than when the etching stop layer is not introduced.

  The semiconductor laser 210 is mounted in a state where the light emitting end face 2122 is optically coupled to the optical coupling end face 1062 of the optical waveguide core 106, and the lower element electrode 216 is electrically connected to the first electric wiring 118. More specifically, the light emitting end face 2122 of the semiconductor laser 210 is disposed so as to be close to the optical coupling end face 1062 of the optical waveguide core 106. That is, the XYZ position of the light emitting end face 2122 of the semiconductor laser 210 so that the laser light emitted from the light emitting end face 2122 of the semiconductor laser 210 is optically coupled to the optical coupling end face 1062 of the optical waveguide core 106 with the maximum optical coupling efficiency. Is adjusted. In addition, the semiconductor laser 210 is disposed so that the element electrode 216 on the lower surface of the semiconductor laser 210 is in contact with the upper surface of the first electric wiring 118 on both sides or at least one of the protrusions 220. The device electrode 216 on the lower surface of the semiconductor laser 210 is bonded to the first electric wiring 118 by solder (conductive bonding agent) or gold-gold pressure bonding. Here, a space is formed by removing the first oxide film 120 and the BOX layer 104 between the joint portions between the element electrodes 216 and the first electric wiring 118 at two positions on both sides of the protrusion 220. The protrusion 220 of the semiconductor laser 210 is accommodated in this space, and the element electrode 216 of the semiconductor laser 210 is in contact with the first electric wiring 118 on the upper surface side of the first electric wiring 118. The height of the active layer 212 measured from the surface of the device electrode 216 is the same as the height of the waveguide core 106 measured from the surface of the electrode pad of the first electric wiring 118, or the device electrode on the lower surface of the semiconductor laser 210. The height is the sum of the thickness of the solder (conductive bonding agent) between 216 and the first electric wiring 118.

  With such a configuration, the device electrode 216 on the lower surface of the semiconductor laser 210 is placed at a position where the height from the substrate 102 is higher than that of the optical waveguide core 106 while the waveguide core 106 and the active layer 212 are set to the same height. It is possible to make an electrical connection directly to the formed first electrical wiring 118. That is, an electrical wiring for electrically connecting to the device electrode 216 on the lower surface of the semiconductor laser 210 is directly formed on the surface of the substrate 102, or an electrical wiring on the surface of the substrate 102 formed in this manner and a position higher than that. The semiconductor laser 210 can be mounted on the substrate 102 without being connected to the first electrical wiring 118 in FIG. Further, in this configuration, since the contact area between the device electrode 216 on the lower surface of the semiconductor laser 210 and the first electric wiring 118 and the first oxide film 120 is relatively wide, the heat generated when the semiconductor laser 210 is driven can be efficiently transferred to the substrate. The heat can be dissipated to the 102 side.

  In FIG. 2, the semiconductor laser 210 is disposed so that the element electrode 216 on the lower surface of the semiconductor laser 210 is in contact with the upper surface of the first electric wiring 118 on both sides or at least one of the protrusions 220. As described above, the lower surface 218 of the semiconductor laser may be supported in contact with the surface of the second oxide film 126 that is a protective film positioned above the first electric wiring 118. In this case, the element electrodes 214 and 216 of the semiconductor laser are joined to the first electric wiring 118 a and the first electric wiring 118 b through the solder 128. By adjusting the amount of solder, after melting the solder, at least a part of the lower surface 218 of the semiconductor laser is pressed against the second oxide film 126 due to thermal contraction of the solder. As a result, the light emitting end face 2122 is optically coupled to the optical coupling end face 1062 of the optical waveguide core 106 with high reproducibility without including a solder thickness error. Also, in FIG. 11, the structure of the semiconductor laser 210 is devised, and the device electrode 214 arranged on the back surface of the semiconductor laser in FIG. 2 is arranged on the same active layer side as the device electrode 216, thereby omitting the wire bonding step. Making it possible. The element electrode 214 and the element electrode 216 are electrically separated by an insulating layer 217.

<Third Embodiment>
FIG. 3 is a cross-sectional configuration diagram of an optical integrated circuit device 300 according to the third embodiment of the present invention. In FIG. 3, the same components as those of the optical integrated circuit device 100 are denoted by the same reference numerals. In the optical integrated circuit device 300, the optical coupling end face 1062 of the optical waveguide core 106 is configured as an end face that is not perpendicular to the substrate 102. Specifically, the optical coupling end face 1062 is configured by an inclined surface that protrudes upward. The inclination angle of the optical coupling end face 1062 is, for example, 1 ° or less. Such an inclined surface can be formed by depositing an oxide film on the vertical end surface by using, for example, a chemical vapor deposition apparatus if an optical coupling end surface substantially perpendicular to the substrate 102 can be formed in advance. It is. In many chemical vapor deposition apparatuses, when an oxide film is deposited on a vertical end surface, the deposition rate becomes slower as the position is closer to the substrate 102, so that such an inclined surface protruding upward can be formed.

  According to the configuration of the optical integrated circuit device 300 in FIG. 3, the laser light emitted from the tilted semiconductor laser 110 is refracted in the length direction of the waveguide core 106 at the tilted optical coupling end face 1062. As a result, the optical axis of the refracted light coincides with the optical axis of the waveguide core 106, and the laser beam is coupled to the optical waveguide having the optical waveguide core 106 with higher optical coupling efficiency than in the case where there is no inclination of the end face. can do.

<Fourth embodiment>
FIG. 4 is a cross-sectional configuration diagram of an optical integrated circuit device 400 according to the fourth embodiment of the present invention. In FIG. 4, the same components as those of the optical integrated circuit device 100 are denoted by the same reference numerals. The optical integrated circuit device 400 includes a sealing cap member 402. The sealing cap member 402 is installed on the substrate 102 so as to accommodate the semiconductor laser 110 in its internal space. The sealing cap member 402 can be made of, for example, resin, glass, ceramic, metal, or the like. An adhesive, solder, gold-gold pressure bonding, or the like can be applied to the sealing cap member 402. According to such a configuration, the semiconductor laser 110 is protected from the external environment, and the reliability of the optical integrated circuit device 400 as a whole can be improved.

<Fifth Embodiment>
FIG. 5 is a cross-sectional configuration diagram of an optical integrated circuit device 500 according to the fifth embodiment of the present invention. In FIG. 5, the same components as those of the optical integrated circuit device 100 are denoted by the same reference numerals. The optical integrated circuit device 500 includes a glass sealing cap member 502. The glass sealing cap member 502 is installed on the substrate 102 so as to accommodate the semiconductor laser 110 in its internal space. A cap electrode 504 is formed on the inner wall surface of the glass sealing cap member 502. The cap electrode 504 is disposed from the back surface of the glass sealing cap member 502, that is, from the upper surface of the inner wall to the side surface of the inner wall. The element electrode 114 on the upper surface of the semiconductor laser 110 is electrically connected to one end of the cap electrode 504 by, for example, solder 506. The other end of the cap electrode 504 extends to the lower portion of the side surface of the inner wall of the glass sealing cap member 502 and is electrically connected to the third electric wiring 124 on the substrate 102. As described above, in the optical integrated circuit device 500, the cap electrode 504 provided on the inner wall surface of the glass sealing cap member 502 is used instead of the gold wire 132 in the optical integrated circuit device 100. The element electrode 114 and the third electric wiring 124 on the substrate 102 are electrically connected. According to such a configuration, the reliability of the optical integrated circuit device 500 can be improved by the glass sealing cap member 502, and the complexity of the manufacturing process can be reduced as compared with the case where the gold wire 132 is used. Can do. In place of the solder 506, another conductor such as a gold bump or a conductive resin may be used.

  The solder 506 (or another conductor) may have a role as a heat transfer body as well as a role as a conductor. In this case, a larger contact area between the solder 506 (or other conductor), the semiconductor laser 110, and the glass sealing cap member 502 is advantageous for heat dissipation. Therefore, as shown in FIG. It is preferable to increase the distribution region of the conductor.

<Sixth Embodiment>
FIG. 6 is a cross-sectional configuration diagram of an optical integrated circuit device 600 according to the sixth embodiment of the present invention. In FIG. 6, the same components as those of the optical integrated circuit device 500 are denoted by the same reference numerals. The optical integrated circuit device 600 includes a glass sealing cap member 602. In addition to the configuration of the glass sealing cap member 502 in the optical integrated circuit device 500, the glass sealing cap member 602 further includes a through via 604 on the upper surface portion thereof. The through via 604 is configured by embedding a metal or a resin material having a high thermal conductivity in a through hole opened in glass (or another insulating material). Furthermore, a heat dissipation member (not shown) may be installed on the upper part of the glass sealing cap member 602, and the heat dissipation member and the metal of the through via 604 may be thermally connected. According to such a configuration, the heat generated when the semiconductor laser 110 is driven can be efficiently radiated not only from the substrate 102 side but also from the heat radiating member installed on the upper part of the glass sealing cap member 602. Is possible. If the filling material of the through via 604 is a conductor such as metal, the semiconductor laser 110 can be driven through the through via 604.

  Further, as shown in FIG. 13, the area of the through via 604 is expanded to an area equivalent to that of the semiconductor laser chip, and is connected to the semiconductor laser chip via a heat conductive (and conductive) material such as solder 506, thereby sealing the glass. It is also possible to greatly improve the heat radiation to the upper part of the stop cap member 602.

<Seventh embodiment>
FIG. 7 is a cross-sectional configuration diagram of an optical integrated circuit device 700 according to the seventh embodiment of the present invention. In FIG. 7, the same components as those of the optical integrated circuit device 500 are denoted by the same reference numerals. The optical integrated circuit device 700 includes a silicon (Si) sealing cap member 702 instead of the glass sealing cap member 502 of the optical integrated circuit device 500. The silicon sealing cap member 702 is installed on the substrate 102 so as to accommodate the semiconductor laser 110 in its internal space. A cap electrode 704 is formed on the inner wall surface of the silicon sealing cap member 702. The cap electrode 704 is disposed from the upper surface of the inner wall of the silicon sealing cap member 702 to the side surface of the inner wall. The side surface of the inner wall of the silicon sealing cap member 702 is composed of an inclined surface formed by anisotropic etching of silicon. The element electrode 114 on the upper surface of the semiconductor laser 110 is electrically connected to one end of the cap electrode 704 by solder 706. The other end of the cap electrode 704 extends to the lower part of the side surface of the inner wall of the silicon sealing cap member 702 and is electrically connected to the third electric wiring 124 on the substrate 102. As described above, the optical integrated circuit device 700 uses the cap electrode provided on the inner wall surface of the silicon sealing cap member 702 in place of the gold wire 132 in the optical integrated circuit device 100, so that the upper surface of the semiconductor laser 110 is used. The element electrode 114 and the third electric wiring 124 on the substrate 102 are electrically connected. According to such a configuration, the reliability of the optical integrated circuit device 700 can be improved by the silicon sealing cap member 702, and the complexity of the manufacturing process can be reduced as compared with the case where the gold wire 132 is used. Can do.

  If the substrate 102 is a silicon substrate, the same thermal expansion coefficient can be obtained by using the silicon sealing cap 702, so that the semiconductor laser 110 of the semiconductor laser 110 can be compared with the case where a sealing cap of another material is used. It is possible to reduce the stress applied to the semiconductor laser 110 and its vicinity during heat generation. As a result, it is possible to suppress an optical axis shift during driving of the semiconductor laser 110 and a wavelength shift due to distortion.

  Further, since the thermal conductivity of silicon itself is higher than that of glass or the like, the heat generated by the semiconductor laser is directed toward the silicon sealing cap 702 by setting the area of the solder 706 to be the same as the area of the semiconductor laser chip. It is possible to escape. Furthermore, if a heat radiating member (not shown) is installed above the silicon sealing cap member 702, the heat generation of the semiconductor laser can be further suppressed, and the deterioration of the light output accompanying the heat generation can be reduced. As a result, the noise of the semiconductor laser itself can be suppressed, and high-quality signal transmission is possible.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this, A various change is possible within the range which does not deviate from the summary.

  For example, in the above embodiment, the configuration using the semiconductor laser as the optical element has been described. However, any optical element other than the semiconductor laser can be applied as long as it has a light incident / exit end face on the side surface. The substrate 102 may have a coating such as an oxide film for the purpose of insulation.

100, 200, 300, 400, 500, 600, 700 Optical integrated circuit device 102 Substrate 1022, 2021 Recess 1030, 1040, 1041, 1050 Square 104 BOX layer 106, 2011, 2012, 2013 Optical waveguide core 1060, 1070 Protective film 1062 Optical coupling end face 108 Oxide film 110, 210, 2000 Semiconductor laser 112, 212 Active layer 1122, 2122 Light incident / exit end face 1124 End face 114, 116, 214, 216, 2001, 2002, 2003 Element electrode 118, 118a, 118b First Electrical wiring 120 First oxide film 122 Second electrical wiring 124 Third electrical wiring 126 Second oxide film 128, 130, 506, 506b, 706 Solder 132 Gold wire 2022, 2023 Notch 2031, 2032 Electrodes of first electrical wiring Head 2034 second electrical wiring electrode pads 2050 semiconductor laser mounting section 217 insulating layer 220 protrusion 402 sealing cap member 502, 602 of glass sealing cap member 504,704 cap electrode 604 through via 702 silicon sealing cap member

Claims (12)

A substrate,
An optical waveguide core formed at a position higher than the surface of the substrate and having an optical coupling end surface perpendicular or substantially perpendicular to the substrate;
One or more first electrical wirings formed at a position higher than the surface of the substrate and the optical waveguide core;
An optical element having an end surface of the light incident / exiting portion on the side surface and a first element electrode on the lower surface,
Said optical element, said first element electrode together with an end face of the light incident and exit section is close to the optical coupling end face of the optical waveguide core is in contact with said first electrical wiring,
The optical element is disposed to be inclined with respect to the substrate such that an end surface of the light incident / exiting portion is close to the substrate and an end surface opposite to the end surface of the light incident / exiting portion is far from the substrate. ,
An optical integrated circuit device. The lower surface of the optical element is supported by at least the front surface of the substrate and the first electric wiring, so that the optical element is disposed to be inclined with respect to the substrate. 2. The optical integrated circuit device according to 1. The lower surface of the optical element, by being supported by the holding Mamorumaku on at least the said surface and said first electric wiring board, said optical element is tilted with respect to the substrate The optical integrated circuit device according to claim 1 . A first oxide film and a second oxide film are laminated on the surface of the substrate, and a part of the plurality of first electric wirings is disposed in the first oxide film, and the second oxide film another part is characterized in that it is provided, an optical integrated circuit device according to any one of claims 1 to 3 of the plurality of first electric wires within. The first element electrode of the optical element is joined to the first electric wiring by a conductive joint provided on the first electric wiring, so that the lower surface of the optical element is the first electric wiring. The optical integrated circuit device according to claim 2 , wherein the optical integrated circuit device is partially supported by the electrical wiring. A concave portion is formed in a portion of the surface of the substrate in contact with the optical element, and the optical element has an end portion on the end surface side of the light incident / exiting portion of the lower surface accommodated in the concave portion. The optical integrated circuit device according to claim 2, claim 3, or claim 5 . The light according to claim 6 , wherein the recess includes a cutout portion that partially accommodates the first element electrode so that the first element electrode does not contact the surface of the substrate. Integrated circuit device. It said protective film, according to claim 3, characterized in that it comprises the cutout portion and the first element electrode and the substrate surface to accommodate the first element electrodes partially so as not to contact Optical integrated circuit device. Said optical coupling end face, the optical integrated circuit device according to any one of claims 1 to 8, characterized in that it is inclined so that the top is pushed out. A second element electrode on the upper surface of the optical element;
A cap covering the optical element and having an edge fixed on the substrate;
One or more second electrical wirings formed on the substrate at a position higher than the optical waveguide core,
The cap includes a first cap electrode distributed continuously from at least a part of the inner wall surface to the edge,
The first cap electrode and the second element electrode are connected by a conductor,
The second electrical wiring is in contact with at least a portion of the portion distributed on the edge of the first cap electrode;
Optical integrated circuit device according to any one of claims 1 to 9, characterized in. The optical integrated circuit device according to claim 10 , wherein the cap is made of glass or Si. The cap has one or more second cap electrodes on its outer surface;
One or more through vias penetrating the cap and electrically connecting the first cap electrode and the second cap electrode;
Optical integrated circuit device according to claim 10 or claim 11, characterized in that it comprises a.

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