Photoelectric composite structure, method of manufacturing the same, photoelectric composite module, and optical communication cable

Abstract

To provide a technique suitable for improving reliability of optical communication.SOLUTION: The photoelectric composite structure 560 is used for optical communication of a c channel or less. The c cores 543 are optically connected to the c device regions 562 on a one to-one basis. The c * s bumps 554 are bonded to the c element regions 562 on an s-to-s basis, thereby electrically connecting the c element regions 562 to the substrate 514. One bump row BA including δ bumps 555 and c * s bumps 554 is formed. The optical element 552 is bonded to the substrate 514 by the bump row BA.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to an optoelectronic composite structure and a manufacturing method thereof, an optoelectronic composite module, and an optical communication cable. [Background technology]

[0002] Flip-chip bonding is known as a technique for bonding an element to a substrate, and is described in Patent Documents 1 and 2. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-174165 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-332056 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a technique suitable for improving the reliability of optical communications. [Means for solving the problem]

[0005] The present invention provides When c is a natural number greater than or equal to 1, s is a natural number greater than or equal to 1, and δ is a natural number greater than or equal to 1, an optical element including c element regions that convert between light and electricity; an optical waveguide including c cores; c×s bumps, δ bumps; a substrate, the c cores are optically connected to the c element regions in a one-to-one relationship; the c×s bumps are bonded to the c element regions in an s-to-1 ratio, thereby electrically connecting the c element regions to the substrate; A bump row is formed including the δ bumps and the c×s bumps, the optical element is bonded to the substrate by the bump row; A photoelectric composite structure for optical communication of up to c channels is provided. [Effects of the Invention]

[0006] The present invention is suitable for improving the reliability of optical communications. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a configuration diagram of an optical communication cable according to an embodiment. [Figure 2] FIG. 2 is an enlarged view of the element portion and its periphery according to the embodiment. [Figure 3] FIG. 3 is an enlarged view of the element portion and its periphery according to the embodiment. [Figure 4] FIG. 4 is an explanatory diagram of a communication path of an optical communication cable according to the embodiment. [Figure 5] FIG. 5 is a cross-sectional view of a portion of the optical communication cable according to the embodiment. [Figure 6] FIG. 6 is a block diagram showing the components of the photoelectric composite module. [Figure 7] FIG. 7 is a block diagram showing the components of the photoelectric composite module. [Figure 8] FIG. 8 is an explanatory diagram of the bumps, pads, and cores. [Figure 9] FIG. 9 is an explanatory diagram of a mirror alignment system according to an embodiment. [Figure 10] FIG. 10 is an explanatory diagram of flip-chip bonding according to the embodiment. [Figure 11] FIG. 11 is a perspective view of an optoelectronic composite structure according to an embodiment. [Figure 12] FIG. 12 is an explanatory diagram of stress during flip-chip bonding according to the embodiment. [Figure 13] FIG. 13 is an explanatory diagram of stress during flip-chip bonding according to the reference embodiment. [Figure 14] FIG. 14 is a partially enlarged view showing the warpage of the substrate and the positions of the bumps. [Figure 15] FIG. 15 is an explanatory diagram of specifications regarding bump bonding in an optical element. [Figure 16] FIG. 16 is an explanatory diagram of the positional relationship between the core and the bumps in a plan view. [Figure 17] FIG. 17 is an explanatory diagram of the positional relationship between the core and the bumps in a plan view. [Figure 18] FIG. 18 is an explanatory diagram of a variation. [Figure 19] FIG. 19 is an explanatory diagram of a variation. [Figure 20] FIG. 20 is an explanatory diagram of a variation. [Figure 21] FIG. 21 is an explanatory diagram of a variation. [Figure 22] FIG. 22 is an explanatory diagram of a variation. [Figure 23] FIG. 23 is an explanatory diagram of a variation. [Figure 24] FIG. 24 is an explanatory diagram of a variation. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the following is merely an example of an embodiment of the present invention and is not intended to limit the present invention.

[0009] [Embodiment] 1 is a configuration diagram of an optical communication cable 300 according to an embodiment. The optical communication cable 300 includes a terminal unit 100, a terminal unit 200, and a cable unit 360. The terminal unit 100 and the terminal unit 200 are connected by the cable unit 360. In the embodiment, the optical communication cable 300 is an active optical cable.

[0010] The terminal unit 100 includes a plug 111 , a PCBA (Printed Circuit Board Assembly) 112 , a connector 113 , an element unit 150 , a substrate 114 , a connector 115 , a connector 116 , and a housing 105 .

[0011] The plug 111 and the PCBA 112 are electrically connected. The PCBA 112 and the substrate 114 are electrically connected via a connector 113. With the element section 150 mounted on the substrate 114, the substrate 114 and the element section 150 are electrically connected. The element section 150 is optically connected to the cable section 360 via a connector 115 and a connector 116 in this order. The PCBA 112, the connector 113, the element section 150, the substrate 114, the connector 115, and the connector 116 are housed in a housing 105.

[0012] In the embodiment, the plug 111 is a USB (Universal Serial Bus) plug, specifically a USB Type-C plug. The connector 113 is an electrical connector, specifically a ZIF (Zero Insertion Force) connector. The connector 115 is an optical connector, specifically a PMT (Connector For Polymer Waveguides Connected With Mechanical Transfer Connector) connector. The connector 116 is an optical connector, specifically an MT (Mechanical Transfer Connector) connector. The connectors 115 and 116 are aligned by guide pins.

[0013] The terminal unit 200 includes a plug 211 , a PCBA 212 , a connector 213 , an element unit 250 , a substrate 214 , a connector 215 , a connector 216 , and a housing 205 .

[0014] The plug 211 and the PCBA 212 are electrically connected. The PCBA 212 and the substrate 214 are electrically connected via a connector 213. With the element section 250 mounted on the substrate 214, the substrate 214 and the element section 250 are electrically connected. The element section 250 is optically connected to the cable section 360 via a connector 215 and a connector 216 in this order. The PCBA 212, the connector 213, the element section 250, the substrate 214, the connector 215, and the connector 216 are housed in a housing 205.

[0015] In the embodiment, plug 211 is a USB plug, specifically a USB Type-C plug. Connector 213 is an electrical connector, specifically a ZIF connector. Connector 215 is an optical connector, specifically a PMT connector. Connector 216 is an optical connector, specifically an MT connector. Connectors 215 and 216 are aligned by guide pins.

[0016] Hereinafter, a natural number c will be used. c is the number of channels in the optical communication cable 300. c is a natural number equal to or greater than 1. For example, c is a natural number equal to or less than 20. In this embodiment, c is 4.

[0017] The optical communication cable 300 is capable of optical communication of c channels. However, the number of channels used in optical communication by the optical communication cable 300 may be less than c. In that case, there may be one or more channels that are not used for optical communication.

[0018] The element section 150 includes a driver circuit 151 and a light emitting element 152. In this embodiment, the driver circuit 151 is a driver integrated circuit (IC), and the light emitting element 152 is a semiconductor element.

[0019] The element section 250 includes an amplifier circuit 251 and a light receiving element 252. In this embodiment, the amplifier circuit 251 is a transimpedance amplifier. The light receiving element 252 is a semiconductor element.

[0020] Fig. 2 is an enlarged view of the element section 150 and its periphery according to the embodiment. Fig. 3 is an enlarged view of the element section 250 and its periphery according to the embodiment. In Figs. 2 and 3, the connectors 113, 213, etc. are omitted from the illustration.

[0021] The driver circuit 151 is electrically connected to a connection portion 113a on the substrate 114 by a conductor 153. In the illustrated example, the conductor 153 is a conductor pattern. Specifically, the conductor 153 has a plurality of conductive paths, each of which is included in a corresponding channel. The connector 113 is electrically connected to the connection portion 113a.

[0022] The amplifier circuit 251 is electrically connected to a connection portion 213a on the substrate 214 by a conductor 253. In the illustrated example, the conductor 253 is a conductor pattern. Specifically, the conductor 253 has a plurality of conductive paths, each of which is included in a corresponding channel. The connector 213 is electrically connected to the connection portion 213a.

[0023] 4 is an explanatory diagram of a communication path 450 of the optical communication cable 300 according to the embodiment. In the communication path 450, a driver circuit 151, a light emitting element 152, a cable part 360, a light receiving element 252, and an amplifier circuit 251 are provided in this order.

[0024] The driver circuit 151 includes c drivers 161. In this embodiment, the c drivers 161 are four drivers 161: a first driver 1611, a second driver 1612, a third driver 1613, and a fourth driver 1614.

[0025] The light emitting element 152 includes c element regions 162. In this embodiment, the c element regions 162 are four element regions 162: a first element region 1621, a second element region 1622, a third element region 1623, and a fourth element region 1624.

[0026] The cable portion 360 includes a c-core optical cable, i.e., includes c optical transmission lines 365. In an embodiment, the c optical transmission lines 365 include a first optical transmission line 3651, a second optical transmission line 3652, a third optical transmission line 3653, and a fourth optical transmission line 3654.

[0027] The light receiving element 252 includes c element regions 262. In this embodiment, the c element regions 262 are four element regions 262: a first element region 2621, a second element region 2622, a third element region 2623, and a fourth element region 2624.

[0028] The amplifier circuit 251 includes c amplifiers 261. In this embodiment, the c amplifiers 261 are four amplifiers 261: a first amplifier 2611, a second amplifier 2612, a third amplifier 2613, and a fourth amplifier 2614.

[0029] In the embodiment, the communication path 450 includes a first communication path 4601, a second communication path 4602, a third communication path 4603, and a fourth communication path 4604.

[0030] In the first communication path 4601, a first driver 1611, a first element region 1621, a first optical transmission line 3651, a first element region 2621, and a first amplifier 2611 are provided in this order. The first driver 1611 is operated by the drive command generator 125 to generate an electrical signal. The first element region 1621 converts the electrical signal from the first driver 1611 into an optical signal. The optical signal is transmitted to the first element region 2621 via the first optical transmission line 3651. The first element region 2621 converts the optical signal into an electrical signal. The first amplifier 2611 is operated by the amplification command generator 225 to amplify the electrical signal from the first element region 2621.

[0031] In the second communication path 4602, a second driver 1612, a second element region 1622, a second optical transmission line 3652, a second element region 2622, and a second amplifier 2612 are provided in this order. The second driver 1612 is operated by the drive command generator 125 to generate an electrical signal. The second element region 1622 converts the electrical signal from the second driver 1612 into an optical signal. The optical signal is transmitted to the second element region 2622 via the second optical transmission line 3652. The second element region 2622 converts the optical signal into an electrical signal. The second amplifier 2612 is operated by the amplification command generator 225 to amplify the electrical signal from the second element region 2622.

[0032] In the third communication path 4603, a third driver 1613, a third element region 1623, a third optical transmission line 3653, a third element region 2623, and a third amplifier 2613 are provided in this order. The third driver 1613 is operated by the drive command generator 125 to generate an electrical signal. The third element region 1623 converts the electrical signal from the third driver 1613 into an optical signal. The optical signal is transmitted to the third element region 2623 via the third optical transmission line 3653. The third element region 2623 converts the optical signal into an electrical signal. The third amplifier 2613 is operated by the amplification command generator 225 to amplify the electrical signal from the third element region 2623.

[0033] The fourth communication path 4604 includes a fourth driver 1614, a fourth element region 1624, a fourth optical transmission line 3654, a fourth element region 2624, and a fourth amplifier 2614, arranged in this order. The fourth driver 1614 is operated by the drive command generator 125 to generate an electrical signal. The fourth element region 1624 converts the electrical signal from the fourth driver 1614 into an optical signal. The optical signal is transmitted to the fourth element region 2624 via the fourth optical transmission line 3654. The fourth element region 2624 converts the optical signal into an electrical signal. The fourth amplifier 2614 is operated by the amplification command generator 225 to amplify the electrical signal from the fourth element region 2624.

[0034] Specifically, the drive command generator 125 transmits a drive command to a driver 161 belonging to a channel for optical communication. The driver 161 that receives the drive command supplies an electrical signal to an element region 162 that belongs to the same channel as the driver 161, causing the element region 162 to output an optical signal.

[0035] The amplification command generator 225 transmits an amplification command to the amplifier 261 belonging to the channel for which optical communication is to be performed. The amplifier 261 that has received the amplification command amplifies the electrical signal from the element region 262 that belongs to the same channel as the amplifier 261.

[0036] In this way, signals are propagated using the optical communication cable 300, and communication is carried out.

[0037] In the embodiment, the drive command generator 125 and the amplification command generator 225 are personal computers. The element region 162 is a semiconductor laser, specifically an LD (Laser Diode), and more specifically a VCSEL (Vertical Cavity Surface Emitting LASER). The element region 262 is a photodiode. The optical transmission line 365 is an optical fiber, specifically a POF (Plastic Optical Fiber). The cable portion 360 is a hybrid cable including a c-core optical cable and an electric cable (not shown).

[0038] Fig. 5 is a cross-sectional view of a portion of an optical communication cable 300 according to an embodiment. Fig. 5 shows components of one channel as a representative of the components of c channels. Fig. 5 does not show the housing 105, housing 205, bumps, pads, dummy cores, etc.

[0039] An element section 150 is provided on the front surface 114a side of the substrate 114. That is, c drivers 161 and c element regions 162 are provided on the front surface 114a side of the substrate 114. An optical waveguide 140 is provided on the back surface 114b side of the substrate 114. The optical waveguide 140 includes an underclad 141, an overclad 142, c cores 143, and c mirrors 144. The c cores 143 are disposed between the underclad 141 and the overclad 142.

[0040] An element section 250 is provided on the front surface 214a side of the substrate 214. That is, c amplifiers 261 and c element regions 262 are provided on the front surface 214a side of the substrate 214. An optical waveguide 240 is provided on the back surface 214b side of the substrate 214. The optical waveguide 240 includes an underclad 241, an overclad 242, c cores 243, and c mirrors 244. The c cores 243 are disposed between the underclad 241 and the overclad 242.

[0041] Each of the c optical transmission lines 365 includes a cladding 361 and a core 363. The core 363 is surrounded by the cladding 361.

[0042] Each of the c channels of the optical communication cable 300 includes one element region 162, one mirror 144, one core 143, one optical transmission line 365, one core 243, one mirror 244, and one element region 262. In each channel: The optical signal from the element region 162 is reflected by the mirror 144 and guided to the core 143, Passing through the core 143, the connector 115, the connector 116, the core 363, the connector 216, the connector 215 and the core 243 in this order, The optical signal from the core 243 is reflected by the mirror 244 and guided to the element region 262 .

[0043] 4 and 5, the optoelectronic hybrid board 103 is configured by the substrate 114 and the optical waveguide 140. The optoelectronic hybrid board 203 is configured by the substrate 214 and the optical waveguide 240.

[0044] FIG. 6 is a block diagram showing components of the optoelectronic composite module 120 and the optoelectronic composite module 220 configured in the embodiment.

[0045] The term "optoelectronic composite module" is a concept that encompasses both a module that converts electricity to light and a module that converts light to electricity. The optoelectronic composite module 120 converts electricity to light. The optoelectronic composite module 220 converts light to electricity. An example of an optoelectronic composite module is an on-board optics (OBO) in which an optoelectronic composite structure is mounted on a board. Specifically, the optoelectronic composite module 120 may be an OBO in which the optoelectronic composite structure 160 is mounted on a board. The optoelectronic composite module 220 may be an OBO in which the optoelectronic composite structure 260 is mounted on a board.

[0046] The optoelectronic composite module 120 includes an optoelectronic composite structure 160 and a controller 170. The optoelectronic composite structure 160 includes a plug 111, a PCBA 112, a connector 113, a light-emitting element 152, a substrate 114, an optical waveguide 140, and a connector 115. The controller 170 includes a drive command generator 125 and a driver circuit 151.

[0047] The optoelectronic composite module 220 includes an optoelectronic composite structure 260 and a controller 270. The optoelectronic composite structure 260 includes a plug 211, a PCBA 212, a connector 213, a light-receiving element 252, a substrate 214, an optical waveguide 240, and a connector 215. The controller 270 includes an amplification command generator 225 and an amplification circuit 251.

[0048] The following describes the embodiments further using reference numerals in the 500 series and FIGS. 7 to 24. The descriptions using reference numerals in the 500 series and FIGS. 7 to 24, including descriptions of flip-chip bonding, bumps, pads, cores, etc., may be applied to both or either of the optoelectronic composite module 120 and the optoelectronic composite module 220. The descriptions regarding the optoelectronic composite module 120 may be applied to the optoelectronic composite module 520. The descriptions regarding the optoelectronic composite module 220 may be applied to the optoelectronic composite module 520.

[0049] When the description using the reference numerals in the 500 series and FIGS. 7 to 24 is applied to the photoelectric composite module 120, in the following description, for example, The photoelectric composite module 520 is replaced with the photoelectric composite module 120, The photoelectric composite structure 560 is read as the photoelectric composite structure 160; The controller 570 is replaced with the controller 170. The optical element 552 is replaced with the light-emitting element 152, The element region 562 is replaced with the element region 162, Substrate 514 is replaced with substrate 114, The optical waveguide 540 is read as the optical waveguide 140, The command generator 525 is replaced with the drive command generator 125, The signal processing circuit 551 can be read as the driver circuit 151.

[0050] When the description using the reference numerals in the 500 series and FIGS. 7 to 24 is applied to the photoelectric composite module 220, in the following description, for example, The photoelectric composite module 520 is replaced with the photoelectric composite module 220, The photoelectric composite structure 560 is read as the photoelectric composite structure 260; The controller 570 is read as the controller 270, The optical element 552 is replaced with the light receiving element 252, The element region 562 is replaced with the element region 262, Substrate 514 is replaced with substrate 214, The optical waveguide 540 is read as the optical waveguide 240, The command generator 525 is replaced with the amplification command generator 225, The signal processing circuit 551 can be read as the amplifier circuit 251.

[0051] FIG. 7 is a block diagram showing the components of the photoelectric hybrid module 520.

[0052] The optoelectronic composite module 520 includes an optoelectronic composite structure 560 and a controller 570. The optoelectronic composite structure 560 includes a plug 511, a PCBA 512, a connector 513, an optical element 552, a substrate 514, an optical waveguide 540, and a connector 515. The controller 570 includes a command generator 525 and a signal processing circuit 551. In an embodiment, the command generator 525 is a personal computer. The optical element 552 is a semiconductor element.

[0053] The photoelectric composite structure 560 is for optical communication of up to c channels, i.e., the photoelectric composite structure 560 is used for optical communication of up to c channels, and the controller 570 controls optical communication of up to c channels.

[0054] The phrase "the optoelectronic composite structure 560 is for optical communication of c channels or less" encompasses cases where the number of optical communication channels is limited to c or less due to physical constraints based on the number of element regions 562 in the optical element 552, the number of cores 543 in the optical waveguide 540, etc. Furthermore, the phrase "the optoelectronic composite structure 560 is for optical communication of c channels or less" encompasses cases where the number of optical communication channels is limited to c or less due to control constraints based on the number of channels through which commands can be transmitted from the command generator 525 to the signal processing circuit 551 and the number of channels through which signal processing can be performed in the signal processing circuit 551. The phrase "the controller 570 controls optical communication of a maximum of c channels" encompasses cases where the number of optical communication channels is limited to c or less due to the control constraints.

[0055] 7 to 24 are applied to the optoelectronic composite module 220, the optical element 552 is the light-emitting element 152. The controller 570 includes a driver circuit 151 as the signal processing circuit 551. The driver circuit 151 drives the light-emitting element 152 so that a maximum of c element regions 162 in the light-emitting element 152 output optical signals to the optical waveguide 140. Specifically, the controller 570 includes a drive command generator 125 as the command generator 525. The drive command generator 125 transmits drive commands to drivers 161 belonging to channels (a maximum of c channels) for performing optical communication. The driver 161 that receives the drive command supplies electrical signals to the element regions 162 belonging to the same channel as the driver 161, causing the element regions 162 to output optical signals.

[0056] When the descriptions using reference numerals in the 500 series and FIGS. 7 to 24 are applied to the optoelectronic composite module 220, the optical element 552 is the light-receiving element 252. The controller 570 includes an amplifier circuit 251 as the signal processing circuit 551. The amplifier circuit 251 amplifies the electrical signals generated by photoelectric conversion by up to c element regions 262 in the light-receiving element 252. Specifically, the controller 570 includes an amplification command generator 225 as the command generator 525. The amplification command generator 225 transmits an amplification command to the amplifier 261 belonging to the channel (up to c channels) for which optical communication should be performed. The amplifier 261 that has received the amplification command amplifies the electrical signals from the element regions 262 belonging to the same channel as the amplifier 261.

[0057] The photovoltaic composite structure 560 includes a bump, a pad, and a core. FIG. 8 is an explanatory diagram of the bump, the pad, and the core. In the following description, γ is a natural number greater than or equal to 1. δ is a natural number greater than or equal to 1. d is a natural number greater than or equal to 1. γ=c×s. δ=d×s. s is a natural number greater than or equal to 1, and is 2 in this embodiment.

[0058] 8 , the photoelectric composite structure 560 includes c element regions 562, c cores 543, γ=c×s bumps 554, γ=c×s pads 556, γ=c×s pads 558, d cores 547, δ=d×s bumps 555, δ=d×s pads 557, and δ=d×s pads 559. The c element regions 562 are included in the optical element 552.

[0059] There are c sets of configurations in which one element region 562, one core 543, s bumps 554, s pads 556, and s pads 558 correspond to one another. In this way, the element regions 562, the cores 543, the bumps 554, the pads 556, and the pads 558 correspond to one another in a one-to-one, s-to-s-to-s relationship.

[0060] There are d sets of configurations in which one core 547, s bumps 555, s pads 557, and s pads 559 correspond to one another. In this way, the core 547, the bumps 555, the pads 557, and the pads 559 correspond to one another in the ratio of 1:s:s:s.

[0061] Hereinafter, the bump 555 may be referred to as a dummy bump, the core 547 may be referred to as a dummy core, and the pad 557 and the pad 559 may be referred to as dummy pads.

[0062] 8, the bumps 554, the cores 543, the pads 556, and the pads 558 are indicated by diagonal hatching. The dummy bumps 555, the dummy cores 547, the dummy pads 557, and the dummy pads 559 are indicated by dotted hatching. These points also apply to FIGS. 12 to 14 and 18 to 24.

[0063] In each of the c element regions 562 in the optical element 552, conversion between light and electricity occurs. The element regions 562 can be used for optical communication. The core 543 is used for optical communication and is optically connected to the element regions 562. In contrast, the dummy core 547 is not used for optical communication.

[0064] The bumps 554 are bonded to the element regions 562 of the optical element 552. In contrast, the dummy bumps 555 are bonded to the areas of the optical element 552 that are not used for optical communication.

[0065] Pad 558 and dummy pad 559 are provided on optical element 552. Pad 556 and dummy pad 557 are provided on surface 514a of substrate 514. Bump 554 is located between pad 558 and pad 556 and is bonded to pad 558 and pad 556. Dummy bump 555 is located between dummy pad 559 and dummy pad 557 and is bonded to dummy pad 559 and dummy pad 557. These bonds are specifically flip-chip bonds, which will be described later with reference to FIG. 10 .

[0066] A mirror alignment system 507 is configured in the photoelectric composite structure 560. Figure 9 is an explanatory diagram of the mirror alignment system 507 according to the embodiment.

[0067] 9, the components of one channel are shown as a representative of the components of c channels, and the same applies to FIG.

[0068] The mirror alignment system 507 includes an element region 562, a substrate 514, and an optical waveguide 540. The element region 562, the substrate 514, and the optical waveguide 540 are arranged in this order. The substrate 514 includes a light passage position 518. The optical waveguide 540 includes a mirror 544.

[0069] Light passing location 518 is configured to allow light to pass through. Element region 562, light passing location 518, and mirror 544 are aligned to allow light to propagate in this order or the reverse order. In Figure 9, block arrows AR1 and AR2 represent the propagation of light when optical element 552 is light-emitting element 152 and light is output from element region 562.

[0070] In an embodiment, the photoelectric composite structure 560 including the mirror alignment system 507 is fabricated by flip-chip bonding. In an embodiment, flip-chip bonding refers to bonding through the application of load and ultrasonic vibration.

[0071] FIG. 10 is an explanatory diagram of flip-chip bonding according to the embodiment.

[0072] 10(a) shows the element region 562 and the substrate 514 before flip-chip bonding. In the element region 562, s pads 558 and s bumps 554 are provided so that the element region 562, the pads 558, and the bumps 554 are arranged in this order. Opposite to the element region 562, s pads 556 are provided on the surface 514a of the substrate 514.

[0073] 10(b) shows the element region 562 and the substrate 514 during flip-chip bonding. In FIG. 10(b), direction D1 is the thickness direction of the substrate 514. Direction D2 is the in-plane direction of the substrate 514. The thickness direction D1 and the in-plane direction D2 are perpendicular to each other.

[0074] 10(b), a load F1 in a direction toward the substrate 514 along the thickness direction D1 and ultrasonic vibration F2 in an in-plane direction D2 are applied to the element region 562. As a result, the bumps 554 are instantaneously melted and bonded to the pads 556. In this way, the element region 562 is flip-chip bonded to the substrate 514.

[0075] In an embodiment, the bump 554, the pad 556, and the pad 558 include gold (Au), and the bond between the bump 554 and the pad 556 is an Au-Au bond.

[0076] Fig. 11 is a perspective view of a photovoltaic composite structure 560 according to an embodiment. In Fig. 11, the pad 556, the dummy pad 557, the pad 558, and the dummy pad 559 are not shown. This also applies to Figs. 12 to 24.

[0077] In the optoelectronic composite structure 560 shown in FIG. 11 , c cores 543 are optically connected to c element regions 562 in a one-to-one relationship. γ=c×s bumps 554 are bonded to the c element regions 562 in an s-to-one relationship, thereby electrically connecting the c element regions 562 to the substrate 514. A single bump row BA is formed, including δ=d×s dummy bumps 555 and γ bumps 554. The bump row BA bonds the optical element 552 to the substrate 514. Specifically, the only bumps bonding the optical element 552 to the substrate 514 are those belonging to the bump row BA. More specifically, the only bumps bonding the optical element 552 to the substrate 514 are the γ bumps 554 and δ dummy bumps 555. In this case, the mounting area on the substrate 514 can be narrowed, allowing the substrate 514 to be used efficiently.

[0078] The expression "γ=c×s bumps 554 are bonded to c element regions 562 in an s-to-1 ratio" will be explained. This expression indicates that there are c sets of configurations in which s bumps 554 are bonded to one element region 562. Note that c ellipses EL are drawn in FIG. 11. The fact that s reference numerals "554" (two in the example of FIG. 11) are surrounded by ellipses EL indicates that the corresponding s bumps 554 are bonded to one element region 562. This also applies to FIGS. 15 to 17.

[0079] In the embodiment, the optical element 552 is flip-chip bonded to the substrate 514 by the bump array BA. When the photoelectric composite structure 560 has the structure shown in FIG. 11, stress applied to the vicinity of the bump 554 during flip-chip bonding can be alleviated. The vicinity of the bump 554 includes, for example, the bump 554, the pad 556, the pad 558, and their surroundings. This point will be described below with reference to FIGS. 12 and 13.

[0080] Fig. 12 is a cross-sectional view illustrating stress applied to the vicinity of a bonded portion during flip-chip bonding by an ultrasonic mounter M in an embodiment. The cross section of Fig. 12 corresponds to cross section CS parallel to thickness direction D1 in Fig. 11. Fig. 13 is a cross-sectional view illustrating stress applied to the vicinity of a bonded portion during flip-chip bonding in a reference embodiment.

[0081] 12 and 13, the length of each set of three downward arrows lined up next to each other schematically represents the magnitude of stress during flip-chip bonding. From the multiple sets of downward arrows, it can be seen that the stress generated near the bonded portion during flip-chip bonding is greater at the edges than at the center in the in-plane direction D2. This also applies to FIGS. 18 to 24.

[0082] 13 does not include dummy bumps 555. A bump row is formed by only γ bumps 554. Therefore, the stress applied to the vicinity of the bonded portion during flip-chip bonding is shared by only γ bumps 554.

[0083] In contrast, in the embodiment shown in FIG. 12, in addition to γ ​​bumps 554, δ dummy bumps 555 are present. A bump row BA is configured including γ bumps 554 and δ dummy bumps 555. Therefore, the stress applied to the vicinity of bump row BA during flip-chip bonding is shared not only by the vicinity of the γ bumps 554 but also by the vicinity of the δ dummy bumps 555. This can alleviate the stress applied to the vicinity of the γ bumps 554. This stress alleviation effect can suppress the occurrence of cracks near the bumps 554. For these reasons, the dummy bumps 555 can contribute to improving the reliability of optical communications.

[0084] The inventors have experimentally found that when flip-chip bonding is performed using a single bump row BA to bond the optical element 552 to the substrate 514, cracks are more likely to occur in the weak areas near the bond than when flip-chip bonding is performed using bumps arranged along all four sides. Furthermore, the inventors have experimentally found that the margin for flip-chip bonding conditions suitable for avoiding cracks is narrower in the former case than in the latter case, and that strict conditions must be set to prevent cracks. While the details of the difference between the former and latter cases remain to be explored, one possible reason is that it is more difficult to stably apply the load F1 and ultrasonic vibration F2 to the bond in the former case than in the latter case. In this embodiment, the former configuration is adopted, and therefore the stress relaxation effect provided by the dummy bumps 555 is more beneficial.

[0085] In the embodiment, the substrate 514 has warpage. The warpage of the substrate 514 occurs during flip-chip bonding and may remain in the product. The warpage of the substrate 514 may cause large stress to be applied near the bonded portion, particularly at the end side in the in-plane direction D2, during flip-chip bonding. Warpage of the substrate 514 is likely to become apparent when the substrate 514 is a flexible substrate. In the embodiment, the substrate 514 is a resin substrate having a thickness of 1 μm or more and 200 μm or less. Such a substrate 514 may be a flexible substrate. The resin constituting the resin substrate is, for example, polyimide.

[0086] FIG. 14 is a partially enlarged view of FIG. 12 to explain the warpage of the substrate 514 and the position of the bumps. As shown in FIG. 14, in this embodiment, the substrate 514 includes a first portion 514x and a second portion 514y. The substrate 514 is warped such that the distance Ly between the second portion 514y and the optical element 552 is shorter than the distance Lx between the first portion 514x and the optical element 552. The bumps 554, where γ=c×s, include a first specific bump 554x. The dummy bumps 555, where δ=d×s, include a second specific bump 555y. The first specific bump 554x is bonded to the first portion 514x. The second specific bump 555y is bonded to the second portion 514y. In this configuration, during flip-chip bonding, the first specific bump 554x is located in a position where the warpage is smaller than that of the second specific bump 555y. Therefore, the vicinity of the second specific bump 555y is sacrificed, so to speak, to protect the vicinity of the first specific bump 554x. This reduces the risk of cracks occurring due to stress in the weak portion near the first specific bump 554x, which has a large impact on communication functions. In the illustrated example, the second portion 514y is located closer to the end in the in-plane direction D2 than the first portion 514x.

[0087] 8, in this embodiment, a pad array PA is provided on the substrate 514. The pad array PA includes γ pads 556 and δ dummy pads 557. The bump array BA and the pad array PA are bonded to each other, thereby bonding the optical element 552 to the substrate 514. Each bump in the bump array BA and each pad in the pad array PA contains gold. This configuration may be a trace of the optical element 552 being flip-chip bonded to the substrate 514.

[0088] Typically, optical elements are small in size. Therefore, there are space limitations for providing bumps on optical elements. FIG. 15 is a plan view observed along the thickness direction D1 to explain specifications for bump bonding in an optical element 552. In this embodiment, the optical element 552 has specifications for bump bonding in a predetermined linear region SR in the optical element 552. For example, the specifications issued by the manufacturer of the optical element 552 state that bump bonding should be performed along the predetermined linear region SR in the optical element 552. The bump row BA is bonded to the linear region SR.

[0089] 16 and 17 are explanatory diagrams of the positional relationship between the cores and the bumps in a plan view. In this embodiment, c cores 543 and γ=c×s bumps 554 face each other in a pair of s. That is, there are c sets of configurations in which one core 543 faces s bumps 554.

[0090] The expression "the core 543 and the bump 554 face each other" will be described. This expression encompasses a state in which, as shown in FIG. 16, at least a portion of the core 543 and at least a portion of the bump 554 overlap in a planar view. This expression also encompasses a state in which, as shown in FIG. 17, a distance G1 between the core 543 and the bump 554 in a width direction Dw1 of the core 543 is less than a width W1 of the core 543 in a planar view. Note that the distance G1 between the core 543 and the bump 554 in the width direction Dw1 of the core 543 may be less than twice the width W1 of the core 543. The width direction Dw1 of the core 543 is a direction perpendicular to the extension direction De1 of the core 543. The planar view refers to a state observed along the thickness direction D1.

[0091] In the embodiment, d dummy cores 547 and δ=d×s dummy bumps 555 face each other in a pair of s. That is, there are d sets of configurations in which one dummy core 547 faces s dummy bumps 555.

[0092] The expression "the dummy core 547 and the dummy bump 555 face each other" will be described. This expression encompasses a mode in which at least a portion of the dummy core 547 and at least a portion of the dummy bump 555 overlap in a plan view, as shown in FIG. 16. This expression also encompasses a mode in which, in a plan view, a distance G2 between the dummy core 547 and the dummy bump 555 in a width direction Dw2 of the dummy core 547 is less than a width W2 of the dummy core 547, as shown in FIG. 17. Note that the distance G2 between the dummy core 547 and the dummy bump 555 in the width direction Dw2 of the dummy core 547 may be less than twice the width W2 of the dummy core 547. The width direction Dw2 of the dummy core 547 is a direction perpendicular to the extension direction De2 in which the dummy core 547 extends.

[0093] In this embodiment, the extension direction De1 and the extension direction De2 are the same, and the width direction Dw1 and the width direction Dw2 are the same.

[0094] In this embodiment, s is an even number. This configuration is advantageous from the viewpoint of stabilizing the bond between the substrate 514 and the element region 562. Specifically, in this embodiment, s is 2.

[0095] 18 to 24 are cross-sectional views showing a variation of an optoelectronic composite structure 560 and its flip-chip bonding. The optoelectronic composite structure 560 will be further described below with reference to FIG. 12 and FIGS.

[0096] 12 and 18 to 24, δ is a natural number equal to or greater than 2. Specifically, δ can be a natural number equal to or greater than 2×s. A large number of dummy bumps 555 is advantageous in terms of improving the reliability of optical communication.

[0097] In the examples of FIGS. 12 and 18 to 24, the δ dummy bumps 555 include a first terminal bump 555a located at one end of the bump row BA. The δ dummy bumps 555 include a second terminal bump 555b located at the other end of the bump row BA. As described above, warping can occur in the substrate 514 during flip-chip bonding. The warping can cause large stress to be applied to the end side of the bonded portion in the in-plane direction D2, and therefore large stress to be applied near the end of the bump row BA. For this reason, using dummy bumps 555 rather than bumps 554 as the bumps located at the ends of the bump row BA is advantageous from the perspective of improving the reliability of optical communications.

[0098] 22 and 23, the γ=c×s bumps 554 include two bumps 554a and 554b, and the δ dummy bumps 555 include an intermediate bump 555c located between the two bumps 554a and 554b.

[0099] 19, 21, 23, and 24, the δ dummy bumps 555 include a first bump group 555J. The first bump group 555J includes 2×s bumps. The 2×s bumps include a first terminal bump 555a and are adjacent to each other in a bump row BA.

[0100] 19 and 23, the δ dummy bumps 555 include a second bump group 555K. The second bump group 555K includes 2×s bumps. The 2×s bumps include the second terminal bump 555b and are adjacent to each other in the bump row BA.

[0101] The following describes techniques that can be applied to the embodiments.

[0102] In the embodiment, a first converter that converts electricity to light is configured using the terminal unit 100. A second converter that converts light to electricity is configured using the terminal unit 200. The first converter and the second converter are connected by a cable unit 360. Both the first converter and the second converter may include the photoelectric composite structure 560, or only one of them may include the photoelectric composite structure 560.

[0103] The number of channels of the optical communication cable 300, i.e., c, may be any natural number equal to or greater than 1. s may be any natural number equal to or greater than 1. The dummy bump 555 does not have to be associated with the dummy core 547. The dummy core 547 may be absent. The optical transmission line 365 may be GOF (Glass Optical Fiber). The command generator 525, the drive command generator 125, and the amplification command generator 225 may be a DSP (Digital Signal Processor), a microcomputer, etc.

[0104] (Addendum) The present disclosure provides the following techniques.

[0105] (Technology 1) When c is a natural number greater than or equal to 1, s is a natural number greater than or equal to 1, and δ is a natural number greater than or equal to 1, an optical element including c element regions that convert between light and electricity; an optical waveguide including c cores; c×s bumps, δ bumps; a substrate, the c cores are optically connected to the c element regions in a one-to-one relationship; the c×s bumps are bonded to the c element regions in an s-to-1 ratio, thereby electrically connecting the c element regions to the substrate; A bump row is formed including the δ bumps and the c×s bumps, the optical element is bonded to the substrate by the bump row; Optoelectronic composite structure for optical communication below c channel.

[0106] (Technology 2) δ is a natural number greater than or equal to 2. The photoelectric composite structure described in Technology 1.

[0107] (Technology 3) the δ bumps include a first terminal bump located at one end of the bump row; The photoelectric composite structure according to any one of claims 1 to 2.

[0108] (Technology 4) the δ bumps include a second terminal bump located at the other end of the bump row; The photoelectric composite structure described in Technology 3.

[0109] (Technology 5) the c×s bumps include two bumps; The δ bumps include an intermediate bump located between the two bumps. The photovoltaic composite structure according to any one of the first to fourth aspects.

[0110] (Technology 6) the δ bumps include a first group of bumps, the first bump group includes 2×s bumps that are adjacent to each other in the bump row, including the first terminal bump; The photoelectric composite structure described in technique 4. Note that technique 6 may be subordinate to technique 3.

[0111] (Technology 7) the δ bumps include a second group of bumps, the second bump group includes 2×s bumps that are adjacent to each other in the bump row, including the second terminal bump; The photovoltaic composite structure described in technology 6.

[0112] (Technology 8) The substrate is a resin substrate having a thickness of 1 μm or more and 200 μm or less. The photovoltaic composite structure according to any one of the preceding claims.

[0113] (Technology 9) a pad row provided on the substrate; the bump row and the pad row are bonded to each other, thereby bonding the optical element to the substrate; each bump in the bump array and each pad in the pad array comprises gold; The photovoltaic composite structure according to any one of the preceding claims.

[0114] (Technology 10) The optical element is a semiconductor element. The photovoltaic composite structure according to any one of the preceding claims.

[0115] (Technology 11) the optical element has a specification to be bump-bonded in a predetermined linear region of the optical element, the bump row is bonded to the linear region; The photovoltaic composite structure according to any one of the preceding claims.

[0116] (Technology 12) The c cores and the c×s bumps are opposed to each other in s pairs. The photovoltaic composite structure according to any one of the preceding claims.

[0117] (Technology 13) It has d cores, where d is a natural number greater than or equal to 1. The δ bumps are d×s bumps, The d cores and the d×s bumps are opposed to each other in a 1-to-s pair. 13. The photovoltaic composite structure according to any one of claims 1 to 12.

[0118] (Technology 14) The substrate is comprising a first portion and a second portion; the second portion is warped such that the distance between the second portion and the optical element is shorter than the distance between the first portion and the optical element; The c×s bumps include a first specific bump, the δ bumps include a second specific bump, the first specific bump is bonded to the first portion; the second specific bump is bonded to the second portion; 14. The photovoltaic composite structure according to any one of claims 1 to 13.

[0119] (Technology 15) s is an even number, 15. The photovoltaic composite structure according to any one of claims 1 to 14.

[0120] (Technology 16) s is 2, The photovoltaic composite structure described in technology 15.

[0121] (Technology 17) the bumps joining the optical element and the substrate are only the bumps belonging to the bump row; 17. The photovoltaic composite structure according to any one of claims 1 to 16.

[0122] (Technology 18) The photovoltaic composite structure according to any one of the techniques 1 to 17, and a controller for controlling optical communication of up to c channels. Photoelectric composite module.

[0123] (Technology 19) (a) the optical element is a light-emitting element, the controller includes a driver circuit, and the driver circuit drives the light-emitting element so that up to the c element regions in the light-emitting element output optical signals to the optical waveguide; or (b) the optical element is a light receiving element, the controller includes an amplifier circuit, and the amplifier circuit amplifies electrical signals generated by photoelectric conversion in up to the c element regions in the light receiving element; The photoelectric composite module according to Art. 18.

[0124] (Technology 20) a first converter that converts electricity into light; a second converter that converts light into electricity; a cable portion connecting the first converter and the second converter, An optical communication cable, wherein at least one selected from the group consisting of the first converter and the second converter comprises the photoelectric composite structure described in any one of techniques 1 to 17.

[0125] (Technology 21) A method for manufacturing the photovoltaic composite structure according to any one of techniques 1 to 17, comprising: and flip-chip bonding the optical element to the substrate by the array of bumps. [Industrial Applicability]

[0126] According to the technology of the present invention, high quality optical communication can be realized. [Explanation of symbols]

[0127] 100, 200 terminal 103, 203 Optoelectronic mixed board 114, 214, 514 board 120, 220, 520 Photoelectric composite module 125 Drive command generator 140, 240, 540 optical waveguide 143, 243, 543, 547 cores 144, 244, 544 mirrors 150, 250 element section 151 Driver Circuit 152 Light-emitting element 160, 260, 560 photoelectric composite structure 161 Drivers 162, 262, 562 element area 170, 270, 570 controller 225 Amplification Command Generator 251 Amplifier circuit 252 Photodetector 261 Amplifier 300 Optical communication cable 360 Cable section 365 Optical Transmission Line 450 communication channels 507 Mirror Alignment System 514x 1st part 514y 2nd part 525 Command Generator 551 Signal Processing Circuit 552 Optical element 554, 555 Bump 555J, 555K bump group 556, 557, 558, 559 Pads BA Bump Row PA pad row

Claims

1. When c is a natural number greater than or equal to 1, s is a natural number greater than or equal to 1, and δ is a natural number greater than or equal to 1, an optical element including c element regions for converting between light and electricity; an optical waveguide including c cores; c×s bumps; δ bumps; a substrate, the c cores are optically connected to the c element regions in a one-to-one relationship; the c×s bumps are bonded to the c element regions in an s-to-1 ratio, thereby electrically connecting the c element regions to the substrate; a bump row including the δ bumps and the c×s bumps is configured; the optical element is bonded to the substrate by the bump row; Photoelectric composite structure for optical communication below c channel.

2. δ is a natural number greater than or equal to 2. The photovoltaic composite structure of claim 1 .

3. the δ bumps include a first terminal bump located at one end of the bump row; The photovoltaic composite structure of claim 1 .

4. the δ bumps include a second terminal bump located at the other end of the bump row; The photovoltaic composite structure of claim 3 .

5. The c×s bumps include two bumps, the δ bumps include an intermediate bump located between the two bumps; The photovoltaic composite structure of claim 1 .

6. the δ bumps include a first group of bumps, the first bump group includes 2×s bumps that are adjacent to each other in the bump row, including the first terminal bump; The photovoltaic composite structure of claim 4 .

7. the δ bumps include a second group of bumps, the second bump group includes 2×s bumps that are adjacent to each other in the bump row, including the second terminal bump; The photovoltaic composite structure of claim 6 .

8. The substrate is a resin substrate having a thickness of 1 μm or more and 200 μm or less. The photovoltaic composite structure of claim 1 .

9. a row of pads provided on the substrate; the bump row and the pad row are bonded to each other, thereby bonding the optical element to the substrate; each bump in the bump array and each pad in the pad array comprises gold; The photovoltaic composite structure of claim 1 .

10. The optical element is a semiconductor element. The photovoltaic composite structure of claim 1 .

11. the optical element has a specification to be bump-bonded in a predetermined linear region of the optical element, the bump row is bonded to the linear region; The photovoltaic composite structure of claim 1 .

12. The c cores and the c×s bumps are opposed to each other in a pair s. The photovoltaic composite structure of claim 1 .

13. The device has d cores, where d is a natural number equal to or greater than 1. The δ bumps are d×s bumps, The d cores and the d×s bumps are opposed to each other in a pair s. The photovoltaic composite structure of claim 1 .

14. The substrate is comprising a first portion and a second portion; the second portion is warped such that the distance between the second portion and the optical element is shorter than the distance between the first portion and the optical element; The c×s bumps include a first specific bump, the δ bumps include a second specific bump, the first specific bump is bonded to the first portion; the second specific bump is bonded to the second portion; The photovoltaic composite structure of claim 1 .

15. s is an even number, The photovoltaic composite structure of claim 1 .

16. s is 2, The photovoltaic composite structure of claim 15.

17. the bumps joining the optical element and the substrate are only the bumps belonging to the bump row; The photovoltaic composite structure of claim 1 .

18. The photovoltaic composite structure of claim 1; a controller for controlling optical communication of up to c channels; Photoelectric composite module.

19. (a) the optical element is a light-emitting element, the controller includes a driver circuit, and the driver circuit drives the light-emitting element so that up to the c element regions in the light-emitting element output optical signals to the optical waveguide; or (b) the optical element is a light receiving element, the controller includes an amplifier circuit, and the amplifier circuit amplifies electrical signals generated by photoelectric conversion by up to the c element regions in the light receiving element; The photovoltaic composite module according to claim 18.

20. a first converter that converts electricity into light; a second converter that converts light into electricity; a cable portion connecting the first converter and the second converter, 18. An optical communication cable, wherein at least one selected from the group consisting of the first transformer and the second transformer comprises the optoelectronic composite structure of any one of claims 1 to 17.

21. A method for manufacturing a photovoltaic composite structure according to any one of claims 1 to 17, comprising the steps of: and flip-chip bonding the optical element to the substrate by the array of bumps.

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