JP2018195723A - Optical module, manufacturing method thereof and optical transceiver - Google Patents

Abstract

To provide a downsized and high-performance optical module, a manufacturing method thereof, and an optical transceiver.SOLUTION: The present invention relates to an optical module comprising a substrate, a first chip and a second chip. The optical module is characterized in that, in the substrate, an upper surface is stepped in such a manner that an upper side becomes a first upper surface and a lower side becomes a second upper surface. Multiple first connection electrodes are provided on the first upper surface. Multiple third connection electrodes which are disposed at a pitch larger than a pitch of the multiple first connection electrodes and electrically connected with the first connection electrodes are provided on a lower surface. The first chip is mounted on the upper surface of the substrate in such a manner that the first upper surface and a lower surface of the first chip are connected via the multiple first connection electrodes, and includes an electronic circuit that is electrically connected with the multiple first connection electrodes. The second chip is provided on the second upper surface of the substrate, an upper surface of the second chip is connected with the lower surface of the first chip via a second connection electrode that is provided on the upper surface of the second chip, and the second chip includes an optical circuit that is electrically connected with the electronic circuit via the second connection electrode.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an optical module, a manufacturing method thereof, and an optical transceiver.

  In an optical module in which an electronic circuit and an optical circuit are integrated, the electronic circuit chip is flip-chip mounted on the optical circuit chip so that the lower surface of the electronic circuit chip faces the upper surface of the optical circuit chip. A method is known in which a through wiring board is mounted on the same plane as the optical circuit chip in a region of the lower surface of the electronic circuit chip that is not opposed to the optical circuit chip, and is mounted on the circuit board through the through wiring board ( For example, Patent Document 1).

Japanese Patent Laying-Open No. 2015-216169

  However, it is impossible to provide connection electrodes on the circuit board facing the lower surface of the optical circuit. For this reason, the electronic circuit chip is connected to the circuit board via the through wiring board in a region not facing the optical circuit chip, but the number of connection electrodes for connecting to the circuit board is limited. . If an attempt is made to increase the number of connection electrodes for connection to the circuit board, the mounting area will increase.

  An object of the present invention is to provide a small and high-performance optical module, a manufacturing method thereof, and an optical transceiver.

  In one aspect, the optical module is an optical module having a substrate, a first chip, and a second chip, and the substrate has a step on the upper surface, the upper surface being the first upper surface and the lower surface being the second upper surface. A plurality of first connection electrodes provided on the first upper surface and arranged on the lower surface with a pitch larger than the pitch of the plurality of first connection electrodes and electrically connected to the first connection electrode. The first chip is mounted on the upper surface of the substrate so that the first upper surface of the substrate and the lower surface of the first chip are connected via the plurality of first connection electrodes, An electronic circuit electrically connected to the first connection electrode, wherein the second chip is provided on the second upper surface of the substrate, and the second connection electrode provided on the upper surface of the second chip is provided. The upper surface of the second chip is in contact with the lower surface of the first chip. It is comprises the electronic circuit and electrically connected to the optical circuit through the second connection electrode.

  In one aspect, an optical module manufacturing method includes the electronic circuit on an upper surface of a second chip having the optical circuit so that the electronic circuit and the optical circuit are electrically connected via a second connection electrode. A step of mounting the first chip; and after mounting the first chip on the upper surface of the second chip, the upper surface of the substrate has a step having an upper surface as the first upper surface and a lower surface as the second upper surface. And a plurality of third connection electrodes arranged on the lower surface of the substrate at intervals greater than the interval between the plurality of first connection electrodes and electrically connected to the first connection electrode. On the upper surface of the substrate, the first upper surface of the substrate and the lower surface of the first chip are connected via the plurality of first connection electrodes, and the electronic circuit is electrically connected to the plurality of first connection electrodes. Mounting the first chip; and Including.

  In one aspect, the optical transceiver is an optical transceiver including an optical module having a substrate, a first chip, and a second chip, a power supply circuit, and a control circuit, and the substrate has a first upper surface on the upper surface. And the lower side has a step which becomes the second upper surface, a plurality of first connection electrodes are provided on the first upper surface, and the first connection electrodes are disposed on the lower surface with a pitch larger than the pitch of the plurality of first connection electrodes. A plurality of third connection electrodes electrically connected to each other, and the first chip is connected to the first upper surface of the substrate and the lower surface of the first chip via the plurality of first connection electrodes. Mounted on the top surface of the substrate and electrically connected to the plurality of first connection electrodes, the second chip is provided on the second top surface of the substrate, and the second chip Second connection power provided on the upper surface of the chip An optical circuit in which the upper surface of the second chip is connected to the lower surface of the first chip through the second connection electrode and electrically connected to the electronic circuit through the second connection electrode, and the power supply circuit includes the first circuit A power supply voltage is supplied to the chip and the second chip, the control circuit controls the first chip and the second chip, and the optical circuit converts a first electrical signal into a first optical signal. At least a portion and at least a portion of a light receiving circuit for converting the second optical signal into a second electric signal, and the electronic circuit outputs the first electric signal to the light emitting circuit, and the second light signal is output from the light receiving circuit to the second light signal. An electric signal is input.

  As one aspect, a small and high-performance optical module, a manufacturing method thereof, and an optical transceiver can be provided.

1A is a plan view of an optical module according to Comparative Example 1, and FIG. 1B is a cross-sectional view taken along line AA of FIG. FIG. 2 is a cross-sectional view of an optical module according to Comparative Example 2. FIG. 3A is a plan view of the optical module according to the first embodiment, and FIG. 3B is a cross-sectional view taken along line AA of FIG. FIG. 4 is a block diagram of an optical transceiver in which the optical module according to the second embodiment is used. FIG. 5A is a plan view of the optical module according to the second embodiment, and FIG. 5B is a cross-sectional view taken along line AA of FIG. FIG. 6A and FIG. 6B are schematic diagrams illustrating connection relationships in the second embodiment. FIG. 7 is a perspective view illustrating wiring in the mounting substrate in the second embodiment. FIG. 8 is a plan view of the top surface of the optical circuit chip on which the laser chip in Example 2 is mounted. FIG. 9 is a plan view of the lower surface of the electronic circuit chip according to the second embodiment seen through from above. FIG. 10 is a plan view of the upper surface of the mounting substrate in the second embodiment. FIG. 11 is a plan view of the lower surface of the mounting substrate in Example 2 seen through from above. 12A and 12B are cross-sectional views illustrating the method for manufacturing the optical module according to the second embodiment. FIG. 13A and FIG. 13B are cross-sectional views illustrating an optical module mounting method according to the second embodiment. FIG. 14A is a plan view of an optical module according to the third embodiment, and FIG. 14B is a cross-sectional view taken along line AA of FIG. FIG. 15 is a plan view of the mounting substrate in the third embodiment. FIG. 16 is a plan view of an optical module according to the fourth embodiment.

[Comparative Example 1]
1A is a plan view of an optical module according to Comparative Example 1, and FIG. 1B is a cross-sectional view taken along line AA of FIG. As shown in FIGS. 1A and 1B, the optical module 110 includes an electronic circuit chip 10, an optical circuit chip 20, and a circuit board 40. The optical circuit chip 20 is mounted on the circuit board 40. The electronic circuit chip 10 is flip-chip mounted on the upper surface of the optical circuit chip 20 via the connection electrodes 22. An electrode 42 is provided on the upper surface of the circuit board 40, and the upper surface of the optical circuit chip 20 and the electrode 42 are electrically connected via a bonding wire 43.

  In Comparative Example 1, the electronic circuit chip 10 and the optical circuit chip 20 are electrically connected via the connection electrode 22. For this reason, a high-speed electric signal can be transmitted between the electronic circuit chip 10 and the optical circuit chip 20. However, the circuit board 40 is electrically connected to the electronic circuit chip 10 and the optical circuit chip 20 through the bonding wires 43. For this reason, an inductance caused by the bonding wire 43 and a capacitance caused by the electrode 42 are added. This makes it difficult to transmit electrical signals at high speed. Further, since the electrode 42 is provided beside the optical circuit chip 20, high integration is difficult.

[Comparative Example 2]
FIG. 2 is a cross-sectional view of an optical module according to Comparative Example 2. As shown in FIG. 2, in the optical module 112, the optical circuit chip 20 and the through wiring substrate 35 are mounted on the circuit substrate 40. The electronic circuit chip 10 is flip-chip mounted on the optical circuit chip 20 via the connection electrode 22 and on the through wiring substrate 35 via the connection electrode 12. The through wiring board 35 has a through wiring 36. The lower surface of the through wiring board 35 is electrically connected to the circuit board 40 via the connection electrodes 37. The lower surface of the optical circuit chip 20 is bonded to the upper surface of the through wiring substrate 35 using an adhesive 33.

  The distance between the connection electrodes 12 on the lower surface of the electronic circuit chip 10 can be reduced to, for example, about 150 μm because a semiconductor manufacturing technique is used. The distance between the connection electrodes 37 on the upper surface of the circuit board 40 is as large as about 300 μm, for example, when manufactured inexpensively by a general printed wiring board technology. If the distance between the connection electrodes 37 on the upper surface of the circuit board 40 is reduced to, for example, about 150 μm, which is the same as the connection electrode 12 on the lower surface of the electronic circuit chip 10, the circuit board 40 becomes expensive. If the circuit board 40 that is inexpensive and has a large interval between the connection electrodes 37 is used, the electronic circuit chip 10 becomes large. For example, if the interval between the connection electrodes 37 is doubled vertically and horizontally, the chip area is quadrupled. Thus, in Comparative Example 2, it is difficult to provide an inexpensive optical module with a small mounting area.

  FIG. 3A is a plan view of the optical module according to the first embodiment, and FIG. 3B is a cross-sectional view taken along line AA of FIG. In FIG. 3A, the electronic circuit and the optical circuit are shown through. As shown in FIGS. 3A and 3B, the optical module 100 mainly includes an electronic circuit chip 10, an optical circuit chip 20, a mounting substrate 30 and a circuit substrate 40. A mounting board 30 is mounted on the circuit board 40. The electronic circuit chip 10 and the optical circuit chip 20 are mounted on the mounting substrate 30. The upper surface of the mounting substrate 30 has a step with the first upper surface 39 on the upper side and the second upper surface 38 on the lower side. Thereby, a dent (concave part) is formed. The optical circuit chip 20 is mounted in the recess (that is, on the second upper surface 38). An optical circuit 21 is formed near the upper surface of the optical circuit chip 20. The electronic circuit chip 10 is flip-chip mounted on the upper surface of the optical circuit chip 20 and the first upper surface 39 of the mounting substrate 30. An electronic circuit 11 is formed near the lower surface of the electronic circuit chip 10. The electronic circuit chip 10 and the optical circuit chip 20 are, for example, silicon chips. The mounting substrate 30 is, for example, a ceramic substrate or a resin substrate. The mounting substrate 30 has, for example, a plurality of stacked insulating layers 31.

  Electrodes 12 a and 22 a are provided on the lower surface of the electronic circuit chip 10. An electrode 22 b is provided on the upper surface of the optical circuit chip 20. An electrode 12 b is provided on the first upper surface 39 of the mounting substrate 30. The connection electrode 12 is formed by joining the electrodes 12a and 12b. The connection electrode 12 electrically connects the lower surface of the electronic circuit chip 10 and the upper surface of the mounting substrate 30. The connection electrodes 22 are formed by joining the electrodes 22a and 22b. The connection electrode 22 electrically connects the lower surface of the electronic circuit chip 10 and the upper surface of the optical circuit chip 20. An electrode 32 for electrically connecting to the circuit board 40 is provided on the lower surface of the mounting board 30. The electrode 32 is bonded to the electrode 42 provided on the circuit board 40. The electrodes 12a, 12b, 22a, 22b, 32 and 42 are metal layers such as an aluminum layer, a copper layer, or a gold layer, for example. The electrodes 12a and 12b, the electrodes 22a and 22b, and the electrodes 32 and 42 may be connected via bumps. For example, metal bumps such as solder bumps or copper bumps are used as the bumps.

  The pitch L3 of the electrodes 32 is larger than the pitch L1 of the connection electrodes 12 and the pitch L2 of the connection electrodes 22. The pitches L1 and L2 are 150 μm, for example, and the pitch L3 is 300 μm, for example. A wiring 14 is provided in the electronic circuit chip 10. The wiring 14 electrically connects the electronic circuit 11 and the connection electrodes 12 and 22. Wirings 34 a and 34 b are provided in the mounting substrate 30. The wirings 34 a and 34 b electrically connect the connection electrode 12 and the electrode 32. The wiring 34a is a wiring through which a high-speed signal passes, and the wiring 34b is a power supply or ground wiring. The wirings 34 a and 34 b may connect one connection electrode 12 to one electrode 32, or may connect one connection electrode 12 to a plurality of electrodes 32. In addition, the wirings 34 a and 34 b may connect the plurality of connection electrodes 12 to one electrode 32, or may connect the plurality of connection electrodes 12 to the plurality of electrodes 32.

  According to the first embodiment, the plurality of connection electrodes 12 (first connection electrodes) are provided on the first upper surface 39 of the mounting substrate 30 (substrate). A plurality of electrodes 32 (third connection electrodes) that are electrically connected to the connection electrodes 12 are provided on the lower surface of the mounting substrate 30. The electronic circuit chip 10 (first chip) is mounted on the upper surface of the mounting substrate 30 so that the first upper surface 39 of the mounting substrate 30 and the lower surface of the electronic circuit chip 10 are connected via the plurality of connection electrodes 12. . The optical circuit chip 20 is provided on the second upper surface 38, and the upper surface is connected to the lower surface of the electronic circuit chip 10 via the connection electrode 22 provided on the upper surface. The electronic circuit 11 is electrically connected to the connection electrode 12, and the optical circuit 21 is electrically connected to the electronic circuit 11 via the connection electrode 22.

  As described above, the electronic circuit chip 10, the optical circuit chip 20, the mounting substrate 30 and the circuit substrate 40 are connected via the connection electrodes 12 and 22 and the electrodes 32 and 42. Thereby, high-speed electrical signal transmission is possible.

  When the electronic circuit chip 10 is mounted on the mounting substrate 30 and the optical circuit chip 20 after the optical circuit chip 20 is mounted on the second upper surface 38 of the mounting substrate 30, the X and Y of the mounting substrate 30 and the optical circuit chip 20 are set. In addition, high accuracy is required in the alignment in the Z direction. In the first embodiment, the electrodes 22a and 22b are joined to integrate the electronic circuit chip 10 and the optical circuit chip 20, and then the electrodes 12a and 12b are joined. For this reason, it is not necessary to align the mounting substrate 30 and the optical circuit chip 20.

  The electrodes 32 are arranged at a pitch L3 that is larger than the pitch L1 of the connection electrodes 12. Thereby, the pitch L3 can be increased to, for example, about 300 μm, and an inexpensive circuit board 40 can be used. Further, since the pitch L1 can be reduced to, for example, 150 μm, the electronic circuit chip 10 can be reduced in size and inexpensively.

  The electronic circuit 11 is provided on the lower surface of the electronic circuit chip 10, and the optical circuit 21 is provided on the upper surface of the optical circuit chip 20. This shortens the connection distance between the electronic circuit 11 and the optical circuit 21 and facilitates transmission of high-speed signals.

  The second embodiment is an example in which an optical module is used for an optical transceiver. FIG. 4 is a block diagram of an optical transceiver in which the optical module according to the second embodiment is used. As shown in FIG. 4, the optical module 102 includes a transmission circuit 11a, a reception circuit 11b, a semiconductor laser 26a, an optical modulator 21a, a photodetector (PD) 21b, and couplers 25a and 25b. The transmission circuit 11 a and the reception circuit 11 b are mounted on the electronic circuit chip 10. The semiconductor laser 26a, the optical modulator 21a, the PD 21b, and the couplers 25a and 25b are mounted on the optical circuit chip 20. A power supply circuit 41a and a control circuit 41b are mounted on the circuit board 40 on which the optical module 102 is mounted. The optical module 102, the power supply circuit 41a, and the control circuit 41b function as the optical transceiver 101 (optical transceiver module).

  The external power supply circuit 41c supplies power to the power supply circuit 41a. The power supply circuit 41a converts the voltage of the supplied power supply and the like. The power supply circuit 41a supplies power to the transmission circuit 11a and the reception circuit 11b via the mounting substrate 30. The power supply circuit 41 a supplies power to the semiconductor laser 26 a through the mounting substrate 30 and the electronic circuit chip 10. As described above, the power supply circuit 41 a supplies the power supply voltage to the electronic circuit chip 10 and the optical circuit chip 20.

  The external host IC (integrated circuit) 41d is, for example, a CPU (Central Processing Unit) of a computer on which the optical transceiver 101 is mounted. The host IC 41d may be mounted on the circuit board 40. The host IC 41d transmits a control signal for controlling the optical transceiver 101 to the control circuit 41b. The control circuit 41b is, for example, a microcomputer. The control circuit 41b controls the transmission circuit 11a, the reception circuit 11b, and the semiconductor laser 26a based on the control signal received from the host IC 41d. Thus, the control circuit 41b controls the electronic circuit chip 10 and the optical circuit chip 20.

  The host IC 41d transmits a signal to be transmitted to the transmission circuit 11a through the circuit board 40 and the mounting board 30. The transmission circuit 11a outputs a drive signal to the optical modulator 21a based on the signal. The optical modulator 21a modulates the laser beam emitted from the semiconductor laser 26a based on the drive signal and outputs the modulated laser beam to the coupler 25a. The coupler 25a outputs the modulated optical signal to the optical fiber 29a. The coupler 25b outputs the optical signal transmitted through the optical fiber 29b to the PD 21b. The PD 21b converts the optical signal into an electric signal and outputs it to the receiving circuit 11b. The receiving circuit 11b amplifies the electric signal and outputs it to the host IC 41d via the circuit board 40 and the mounting board 30.

  FIG. 5A is a plan view of the optical module according to the second embodiment, and FIG. 5B is a cross-sectional view taken along line AA of FIG. The optical module 102 is mounted on the circuit board 40. A laser chip 26 is mounted on the upper surface of the optical circuit chip 20. The laser chip 26 is provided with a semiconductor laser. A plurality of optical fibers 29 are fixed to the upper surface of the optical circuit chip 20 by a fixture 27. An underfill agent 23 that protects the connection electrode 22 is provided between the electronic circuit chip 10 and the optical circuit chip 20. An underfill agent 13 that protects the connection electrode 12 is provided between the electronic circuit chip 10 and the mounting substrate 30. The lower surface of the optical circuit chip 20 and the second upper surface 38 of the mounting substrate 30 are joined by an adhesive 33. Other configurations are the same as those of the first embodiment.

  FIG. 6A and FIG. 6B are schematic diagrams showing an electrical connection relationship in the second embodiment. FIG. 6A and FIG. 6B illustrate a system of differential signals (positive signal and negative signal) of the transmission unit 60 that transmits an optical signal and the reception unit 62 that receives an optical signal, respectively. . As shown in FIG. 6A, the transmission unit 60 includes a transmission circuit 11a and an optical modulator 21a. The optical modulator 21a is, for example, an MZ (Mach-Zehnder) optical modulator, and intensity-modulates the laser light emitted from the laser chip 26. The transmission circuit 11a includes a drive circuit that outputs an electrical signal that drives the optical modulator 21a. The power supply, the ground, the differential signal positive signal, and the negative signal are supplied from the circuit board 40 to the transmission circuit 11a via the electrode 32, the wiring 34 in the mounting board 30, the connection electrode 12, and the wiring 14. The positive / negative signal output from the transmission circuit 11a is output to the optical modulator 21a through the wiring 14, the connection electrode 22, and the wiring 24.

  As shown in FIG. 6B, the receiving unit 62 includes a receiving circuit 11b and a PD (photo detector) 21b. The PD 21b converts an optical signal into a current signal. The receiving circuit 11b includes, for example, a TIA (Trans impedance Amplifier) that converts a current signal converted by the PD 21b into a voltage signal. The PD 21 b outputs a positive signal and a negative signal to the receiving circuit 11 b via the wiring 24, the connection electrode 22, and the wiring 14. The positive signal and the negative signal amplified by the receiving circuit 11b are output to the circuit board 40 via the wiring 14, the connection electrode 12, the wiring 34, and the electrode 32. The power and ground are supplied from the circuit board 40 to the receiving circuit 11b via the electrode 32, the wiring 34 in the mounting board 30, the connection electrode 12, and the wiring 14. Although FIG. 6B shows that the PD 21b outputs a differential signal, it may be a single-ended output as shown in the block diagram of FIG.

  FIG. 7 is a perspective view illustrating wiring in the mounting substrate in the second embodiment. FIG. 7 shows a single line of differential signal wiring (two signal wirings 34a), a power supply or ground wiring 34b. As shown in FIG. 7, the spacing between the lower surface grid 31 c is larger than the upper surface grid 31 a and the intermediate surface grid 31 b of the mounting substrate 30. The electrode 12b is provided on the grid 31a, and the electrode 32 is provided on the grid 31c. Thereby, the pitch of the electrodes 32 provided on the lower surface of the mounting substrate 30 is larger than the pitch of the electrodes 12 b provided on the upper surface of the mounting substrate 30. For this reason, the pitch is converted so that the signal wiring 34a and the power supply or ground wiring 34b are fanned out at the intermediate surface.

  In FIG. 7, four power supply or ground wirings 34b are provided for one system of signal wirings 34a, but more power supply or ground wirings 34b may be provided for one system of signal wirings 34a. As shown in FIG. 5B, a plurality of power supply or ground wirings 34b may be provided for one system of signal wirings 34a. The plurality of power supply or ground wirings 34 b may be electrically connected within the mounting substrate 30. Thereby, the impedance of the power supply or ground wiring 34b can be reduced. When the number of power supply or ground wirings 34b is increased, as shown in FIG. 5B, the electrode 32 immediately below the second upper surface 38 is used for power supply or ground. Thereby, the impedance of the power supply or ground wiring 34b can be further reduced. Further, in order to reduce the impedance of the power supply or ground wiring 34b, a power supply plane and a ground plane may be provided in the mounting substrate 30, and the power supply or ground wiring 34b may be connected to the power supply plane or the ground plane.

  In order to reduce the loss of the high-speed signal, it is preferable that the signal wiring 34a for transmitting the high-speed signal is short. From this point of view, the electrode 32 immediately below the second upper surface 38 (that is, the optical circuit chip 20) in FIG. 5B is preferably a power supply or ground connection electrode, and preferably does not include a signal connection electrode. Thereby, the signal wiring 34a can be shortened. When transmitting signals of a plurality of channels, a plurality of sets of power supply or ground wirings 34b in FIG. 7 can be provided. In FIG. 7, the electrodes 12a and the electrodes 32 may not be provided on part of the grids 31a and 31c.

  FIG. 8 is a plan view of the top surface of the optical circuit chip on which the laser chip in Example 2 is mounted. As shown in FIG. 8, four channels of laser chips 26 are mounted on the optical circuit chip 20. In the optical circuit chip 20, optical modulators 21a and PDs 21b for four channels are provided. In the optical circuit chip 20, power and ground wirings 24a, optical waveguides 24b to 24d, and a coupler 25 are provided. The laser chip 26 is a chip provided with a semiconductor laser 26a. The coupler 25 is a diffraction grating optical coupler. A plurality of electrodes 22 b are provided on the upper surface of the optical circuit chip 20. The plurality of electrodes 22b are provided in the optical modulator region 54a, the PD region 54b, and the power / ground region 54c.

  The power supply potential and the ground potential are supplied from the electronic circuit chip 10 to the laser chip 26 through the electrode 22b and the wiring 24a of the power supply / ground region 54c. Laser light emitted from the laser chip 26 is transmitted to the optical modulator 21a through the optical waveguide 24b. The drive signal output from the electronic circuit chip 10 is transmitted to the optical modulator 21a via the electrode 22b in the optical modulator region 54a. The optical signal obtained by intensity modulation of the laser light based on the drive signal by the optical modulator 21a is input to the optical fiber via the optical waveguide 24c and the coupler 25, and is transmitted to the receiver of the optical transceiver of another device. On the other hand, the optical signal output from the transmitter of the optical transceiver of another device and transmitted through the optical fiber is transmitted to the PD 21b via the coupler 25 and the optical waveguide 24d. The electrical signal converted from the optical signal by the PD 21b is output to the electronic circuit chip 10 via the electrode 22b in the PD region 54b.

  FIG. 9 is a plan view of the lower surface of the electronic circuit chip according to the second embodiment seen through from above. As shown in FIG. 9, a transmission circuit 11 a and a reception circuit 11 b are provided in the electronic circuit chip 10. A plurality of electrodes 12 a and 22 a are provided on the lower surface of the electronic circuit chip 10. The transmission circuit 11a is electrically connected to the mounting substrate 30 via the electrode 12a in the transmission circuit area 50a and to the optical circuit chip 20 via the electrode 22a in the transmission circuit area 52a. The receiving circuit 11b is electrically connected to the mounting substrate 30 via the electrode 12a in the receiving circuit area 50b and to the optical circuit chip 20 via the electrode 22a in the receiving circuit area 52b. The electrode 12a of the power / ground region 50c is electrically connected to the electrode 22a of the power / ground region 52c via the wiring 14a.

  FIG. 10 is a plan view of the upper surface of the mounting substrate in the second embodiment. As shown in FIG. 10, a plurality of electrodes 12 b are provided on the first upper surface 39. The electrode 12b is not provided on the second upper surface 38. The minimum pitch L1 of the electrodes 12b is, for example, 150 μm. The pitch L1 may not be 150 μm, such as 100 μm or 200 μm. The electrodes 12b in the regions 56a and 56b and the power / ground region 56c are joined to the electrodes 12a of the transmission circuit region 50a, the reception circuit region 50b and the power / ground region 50c of the electronic circuit chip 10, respectively.

  FIG. 11 is a plan view of the lower surface of the mounting substrate in Example 2 seen through from above. As shown in FIG. 11, a plurality of electrodes 32 are provided on the lower surface of the mounting substrate 30. The electrodes 32 are provided in a grid array. The pitch L3 of the electrodes 32 is, for example, 300 μm. The pitch L3 may not be 300 μm, such as 200 μm or 400 μm.

  12A and 12B are cross-sectional views illustrating the method for manufacturing the optical module according to the second embodiment. As shown in FIG. 12A, a laser chip 26 is mounted on the upper surface of the optical circuit chip 20. The electronic circuit chip 10 is flip-chip mounted on the upper surface of the optical circuit chip 20 by bonding the electrodes 22a and 22b. The electrodes 22a and 22b may be directly joined or may be joined via bumps. An underfill agent 23 is provided between the lower surface of the electronic circuit chip 10 and the upper surface of the optical circuit chip 20 so as to seal the connection electrode 22 obtained by bonding the electrodes 22a and 22b.

  As shown in FIG. 12B, the electrodes 12a and 12b are joined to each other on the first upper surface 39 of the mounting substrate 30 in a state where the optical circuit chip 20 is housed in the recess on the second upper surface 38. The electronic circuit chip 10 is flip-chip mounted. The electrodes 12a and 12b may be joined directly or via bumps. An underfill agent 13 is provided between the electronic circuit chip 10 and the first upper surface 39 of the mounting substrate 30 so as to seal the connection electrode 12 in which the electrodes 12a and 12b are joined. An adhesive 33 is introduced between the second upper surface 38 and the lower surface of the optical circuit chip 20 to fix the optical circuit chip 20 to the mounting substrate 30. The underfill agents 13 and 23 and the adhesive 33 are resin insulators such as an epoxy resin.

  FIG. 13A and FIG. 13B are cross-sectional views illustrating an optical module mounting method according to the second embodiment. As shown in FIG. 13A, the optical module 102 is mounted on the upper surface of the circuit board 40 by bonding the electrode 32 to the electrode 42 provided on the upper surface of the circuit board 40. The electrode 32 is a copper bump or a solder bump, for example, and the electrode 42 is a metal layer such as a copper layer or a gold layer. As shown in FIG. 13B, an optical fiber 29 is coupled to a coupler 25 provided on the upper surface of the optical circuit chip 20 using a fixture 27. In this way, the optical module 102 is mounted.

  According to the second embodiment, as shown in FIG. 12A, the electronic circuit chip 10 and the optical circuit chip 20 are electrically connected to the upper surface of the optical circuit chip 20 so as to be electrically connected via the connection electrodes 22. The circuit chip 10 is mounted. Thereafter, as shown in FIG. 12B, the electronic circuit chip 10 is mounted on the upper surface of the mounting substrate 30 so that the upper surface of the mounting substrate 30 and the lower surface of the electronic circuit chip 10 are connected via the connection electrodes 12.

  When the electronic circuit chip 10 is mounted on the mounting substrate 30 and the optical circuit chip 20 after the optical circuit chip 20 is mounted on the second upper surface 38 of the mounting substrate 30, the X and Y of the mounting substrate 30 and the optical circuit chip 20 are set. In addition, high accuracy is required in the alignment in the Z direction. Also in the second embodiment, as in the first embodiment, the electrodes 22a and 22b are joined to integrate the electronic circuit chip 10 and the optical circuit chip 20, and then the electrodes 12a and 12b are joined. For this reason, it is not necessary to align the mounting substrate 30 and the optical circuit chip 20. The same applies to Examples 3 and 4 described later.

  As in the second embodiment, an optical module can be used for an optical transceiver. In this case, the optical circuit 21 receives at least a part of a light-emitting circuit (for example, the semiconductor laser 26a and the optical modulator 21a) that converts the first electrical signal into the first optical signal and the second optical signal that is converted into the second electrical signal. It has at least a part of a circuit (for example, PD 21b). The electronic circuit 11 outputs the first electric signal to the light emitting circuit, and the second electric signal is input from the light receiving circuit.

  The power of the optical circuit 21 is supplied from a part of the plurality of electrodes 32 via a part of the plurality of connection electrodes 12, the electronic circuit chip 10 and the connection electrode 22. Thereby, the optical circuit chip 20 may not be directly electrically connected to the mounting substrate 30.

  Further, the plurality of electrodes 32 are provided immediately below the first upper surface 39 and the second upper surface 38 of the mounting substrate 30. Thereby, even if the pitch L3 of the electrode 32 is large, the magnitude | size of the mounting substrate 30 can be made small. Thereby, the mounting area of the optical module can be reduced.

  The signal wiring 34 a that connects the connection electrode 12 and the electrode 32 that outputs and / or inputs the fastest signal among the plurality of electrodes 32 does not pass directly below the second upper surface 38. Thereby, the length of the signal wiring 34a can be shortened, and high-speed signal transmission is facilitated.

  At least some of the connection electrodes that supply power to the electronic circuit chip 10 among the plurality of electrodes 32 are provided directly below the second upper surface 38. By providing the electrode 32 that supplies power that does not require high-speed transmission immediately below the second upper surface 38, the electrode 32 can be arranged efficiently and the mounting area can be reduced. In addition, the impedance of the power supply or ground wiring 34b can be further reduced.

  FIG. 14A is a plan view of an optical module according to the third embodiment, and FIG. 14B is a cross-sectional view taken along line AA of FIG. As shown in FIGS. 14A and 14B, the optical module 104 is mounted on the circuit board 40. First upper surfaces 39 are provided on both sides in the Y direction of the second upper surface 38 (recess). A power supply substrate 45 is mounted on the first upper surface 39 in the −Y direction of the second upper surface 38. The power supply substrate 45 is a substrate for supplying a power supply potential and a ground potential to the laser chip 26.

  The mounting substrate 30 and the power supply substrate 45 are electrically connected via a connection electrode 46, and the connection electrode 46 includes an electrode 46 b provided on the upper surface of the mounting substrate 30 and an electrode 46 a provided on the lower surface of the power supply substrate 45. Have. The electrodes 46a and 46b are joined directly or via bumps. The optical circuit chip 20 and the power supply substrate 45 are electrically connected via the connection electrode 47. The connection electrode 47 includes an electrode 47 b provided on the upper surface of the optical circuit chip 20 and an electrode 47 a provided on the lower surface of the power supply substrate 45. The electrodes 47a and 47b are joined directly or via bumps.

  The power supply substrate 45 has a wiring 48 that electrically connects the electrodes 46a and 47a. The electrode 47b and the laser chip 26 are electrically connected via the wiring 24a. The power supply potential and the ground potential are supplied from the mounting substrate 30 to the laser chip 26 via the connection electrode 46, the wiring 48, the connection electrode 47, and the wiring 24a.

  FIG. 15 is a plan view of the mounting substrate in the third embodiment. As shown in FIG. 15, the second upper surface 38 of the mounting substrate 30 is provided near the center in the Y direction. A first upper surface 39 is provided in the + Y direction and the −Y direction of the second upper surface 38. The power / ground region 56c is provided on the first upper surface 39 in the −Y direction of the second upper surface 38, and the electrode 46b is provided in the power / ground region 56c. Other configurations are the same as those of the second embodiment, and the description thereof is omitted.

  In an optical transceiver, the element with the highest power consumption is often the laser chip 26. In the second embodiment, the power and ground electrodes 12a and 22a and the wiring 14a supplied to the laser chip 26 are provided on the electronic circuit chip 10. When the power of the laser chip 26 is large, the power supply and ground electrodes 12a and 22a and the wiring 14a are increased, and the area of the electronic circuit chip 10 is increased. The unit price per area of the electronic circuit chip 10 that processes high-speed electrical signals is high, and the price of the optical module 102 increases.

  According to the third embodiment, the connection electrode 46 (fourth connection electrode) is provided on the first upper surface 39 of the mounting substrate 30 and is electrically connected to the electrode 32 and not electrically connected to the electronic circuit chip 10. The power of the laser chip 26 (light emitting element) is supplied not via the electronic circuit chip 10 but via the electrode 32 and the connection electrode 46. Thereby, the area of the electronic circuit chip 10 can be reduced, and the price of the electronic circuit chip 10 can be reduced.

  The power supply substrate 45 (third chip) is mounted on the upper surface of the mounting substrate 30 and the upper surface of the optical circuit chip 20. The first upper surface 39 of the mounting substrate 30 and the lower surface of the power supply substrate 45 are connected via the connection electrode 46, and the upper surface of the optical circuit chip 20 and the lower surface of the power supply substrate 45 are connected via the connection electrode 47 (fifth connection electrode). The power of the laser chip 26 is supplied through the electrode 32, the connection electrode 46, the power supply substrate 45, and the connection electrode 47. Since the wiring 48 in the power supply substrate 45 does not transmit a high-speed electrical signal, the power supply substrate 45 may be an inexpensive substrate, and a silicon substrate, a ceramic substrate, a resin substrate, or the like can be used. Thereby, an inexpensive optical module 104 can be provided.

  Instead of using the power supply substrate 45, the electrodes 46b and 47b may be connected using bonding wires. Further, the pitch of the connection electrodes 46 and 47 may be larger than the pitch L1.

  In Example 3, as shown in FIG. 15, the first upper surface 39 is provided on both sides in the Y direction of the second upper surface 38, and the planar shape of the first upper surface 39 is a U-shape (C-shape). . The first upper surface 39 is not provided in the + Y direction of the second upper surface 38, and the planar shape of the first upper surface 39 may be L-shaped.

  FIG. 16 is a plan view of an optical module according to the fourth embodiment. As shown in FIG. 16, the optical module 106 is mounted on the circuit board 40. The length of the electronic circuit chip 10 in the Y direction may be larger than the length of the second upper surface 38 in the Y direction. Thereby, many circuits and / or wirings can be provided in the electronic circuit chip 10. For example, the number of channels of the optical transceiver can be increased, or the connection electrodes 12 for power supply / ground can be increased. Other configurations are the same as those of the third embodiment, and the description thereof is omitted.

  In the second to fourth embodiments, an example in which the laser chip 26 is mounted on the optical circuit chip 20 has been described. However, a package on which the laser chip is mounted may be mounted on the optical circuit chip 20. Further, a laser may be provided outside, and laser light emitted from the laser may be introduced into the optical circuit chip 20. In addition to the semiconductor laser, a semiconductor optical amplifier may be mounted. A light emitting diode may be used instead of the semiconductor laser. The example in which the optical waveguides 24c and 24d and the optical fiber 29 are coupled by the coupler 25 has been described. However, the optical waveguides 24c and 24d and the optical fiber 29 may be coupled to each other at the end face of the optical circuit chip 20.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

In addition, the following additional notes are disclosed regarding the above description.
(Supplementary Note 1) An optical module including a substrate, a first chip, and a second chip, wherein the substrate has a step on the upper surface, the upper surface being the first upper surface and the lower surface being the second upper surface. A plurality of first connection electrodes are provided on the upper surface, and a plurality of third connection electrodes are disposed on the lower surface at a pitch larger than the pitch of the plurality of first connection electrodes and electrically connected to the first connection electrode. The first chip is mounted on the upper surface of the substrate so that the first upper surface of the substrate and the lower surface of the first chip are connected via the plurality of first connection electrodes, and the plurality of first connections An electronic circuit electrically connected to an electrode, wherein the second chip is provided on a second upper surface of the substrate, and the second chip is provided via a second connection electrode provided on the upper surface of the second chip. The upper surface of the chip is connected to the lower surface of the first chip, and the second connection Optical module having the electronic circuit and electrically connected to the optical circuit through the poles.
(Supplementary note 2) The optical module according to supplementary note 1, wherein the plurality of third connection electrodes are provided immediately below the first upper surface and the second upper surface.
(Supplementary note 3) Supplementary note 1 is that power of the optical circuit is supplied from a part of the plurality of third connection electrodes via a part of the plurality of first connection electrodes, the first chip, and the second connection electrode. Or the optical module of 2.
(Additional remark 4) The process of mounting the 1st chip | tip which has the said electronic circuit on the upper surface of the 2nd chip | tip which has the said optical circuit so that an electronic circuit and an optical circuit may be electrically connected via a 2nd connection electrode, After the first chip is mounted on the upper surface of the second chip, the upper surface of the substrate has a step where the upper surface is the first upper surface and the lower surface is the second upper surface, and a plurality of first connection electrodes are formed on the first upper surface. Provided on the upper surface of the substrate having a plurality of third connection electrodes disposed on the lower surface of the substrate at a larger interval than the plurality of first connection electrodes and electrically connected to the first connection electrode; The first chip such that the first upper surface of the substrate and the lower surface of the first chip are connected via the plurality of first connection electrodes, and the electronic circuit is electrically connected to the plurality of first connection electrodes. And a method for manufacturing an optical module.
(Supplementary Note 5) An optical transceiver including an optical module having a substrate, a first chip, and a second chip, a power supply circuit, and a control circuit, wherein the substrate has an upper surface on the upper surface and a lower surface on the second upper surface. A plurality of first connection electrodes are provided on the first upper surface, arranged at a lower pitch than the pitch of the plurality of first connection electrodes, and electrically connected to the first connection electrodes. A plurality of third connection electrodes, wherein the first chip is disposed on the upper surface of the substrate such that the first upper surface of the substrate and the lower surface of the first chip are connected via the plurality of first connection electrodes. The electronic circuit is mounted and electrically connected to the plurality of first connection electrodes, and the second chip is provided on a second upper surface of the substrate and provided on an upper surface of the second chip. The upper surface of the second chip is connected via the second connection electrode. An optical circuit connected to the lower surface of the first chip and electrically connected to the electronic circuit via the second connection electrode, the power supply circuit supplying a power voltage to the first chip and the second chip; The control circuit controls the first chip and the second chip, and the optical circuit converts at least a part of the light emitting circuit that converts the first electric signal into the first optical signal and the second optical signal. An optical transceiver having at least a part of a light receiving circuit for converting to a second electric signal, wherein the electronic circuit outputs the first electric signal to the light emitting circuit, and the second electric signal is inputted from the light receiving circuit.
(Supplementary Note 6) The light emitting device includes a light emitting element included in the second chip, and is electrically connected to a part of the plurality of third connection electrodes on the first upper surface of the substrate. A fourth connection electrode that is not electrically connected to one chip is provided, and the power source of the light emitting element is supplied through the plurality of third connection electrodes and the fourth connection electrode without passing through the first chip. 5. The optical transceiver according to 5.
(Supplementary note 7) The optical module according to any one of supplementary notes 1 to 3, wherein the electronic circuit is provided on a lower surface of the first chip, and the optical circuit is provided on an upper surface of the second chip.
(Supplementary Note 8) A wiring connecting the third connection electrode that outputs and / or inputs the fastest signal among the plurality of third connection electrodes and a part of the plurality of first connection electrodes is provided on the second upper surface. The optical module according to any one of appendices 1 to 3, which does not pass directly below.
(Supplementary note 9) The optical module according to supplementary note 8, wherein at least a part of the third connection electrode that supplies power to the first chip among the plurality of third connection electrodes is provided immediately below the second upper surface.
(Supplementary Note 10) The first upper surface of the substrate and the lower surface of the third chip are connected via the fourth connection electrode, and the upper surface of the second chip and the lower surface of the third chip are connected via the fifth connection electrode. And the third chip mounted on the first upper surface of the substrate and the second chip, and the power source of the light emitting element is the plurality of third connection electrodes, the fourth connection electrodes, the third chip The optical transceiver according to appendix 6, which is supplied through a chip and the fifth connection electrode.

10 Electronic circuit chip 11 Electronic circuit 12, 22, 32, 46, 47 Connection electrode 12a, 12b, 22a, 22b, 32, 46a, 46b, 47a, 47b Electrode 14, 24, 24a, 34, 34a, 34b, 48 Wiring 20 optical circuit chip 21 optical circuit 24b-24d optical waveguide 26 laser chip 30 mounting substrate 38 second upper surface 39 first upper surface 45 power supply substrate

Claims (6)

An optical module comprising a substrate, a first chip, and a second chip,
The substrate has a step whose upper surface is a first upper surface and a lower surface is a second upper surface, a plurality of first connection electrodes are provided on the first upper surface, and a pitch of the plurality of first connection electrodes is provided on a lower surface. A plurality of third connection electrodes arranged at a larger pitch and electrically connected to the first connection electrodes;
The first chip is mounted on the upper surface of the substrate such that the first upper surface of the substrate and the lower surface of the first chip are connected via the plurality of first connection electrodes, and the plurality of first connection electrodes And an electronic circuit electrically connected to
The second chip is provided on the second upper surface of the substrate, and the upper surface of the second chip is connected to the lower surface of the first chip via a second connection electrode provided on the upper surface of the second chip. An optical module having an optical circuit electrically connected to the electronic circuit through the second connection electrode.   The optical module according to claim 1, wherein the plurality of third connection electrodes are provided immediately below the first upper surface and the second upper surface.   The power of the optical circuit is supplied from a part of the plurality of third connection electrodes via a part of the plurality of first connection electrodes, the first chip, and the second connection electrode. The optical module as described. Mounting the first chip having the electronic circuit on the upper surface of the second chip having the optical circuit so that the electronic circuit and the optical circuit are electrically connected via the second connection electrode;
After mounting the first chip on the upper surface of the second chip, the upper surface of the substrate has a step where the upper surface is the first upper surface and the lower side is the second upper surface, and a plurality of first connection electrodes are provided on the first upper surface. On the lower surface of the substrate, the upper surface of the substrate having a plurality of third connection electrodes disposed at a larger interval than the interval of the plurality of first connection electrodes and electrically connected to the first connection electrode, The first chip is connected so that the first upper surface of the substrate and the lower surface of the first chip are connected via a plurality of first connection electrodes, and the electronic circuit is electrically connected to the plurality of first connection electrodes. Mounting process,
An optical module manufacturing method including: An optical transceiver comprising an optical module having a substrate, a first chip, and a second chip, a power supply circuit, and a control circuit,
The substrate has a step whose upper surface is a first upper surface and a lower surface is a second upper surface, a plurality of first connection electrodes are provided on the first upper surface, and a pitch of the plurality of first connection electrodes is provided on a lower surface. A plurality of third connection electrodes arranged at a larger pitch and electrically connected to the first connection electrodes;
The first chip is mounted on the upper surface of the substrate such that the first upper surface of the substrate and the lower surface of the first chip are connected via the plurality of first connection electrodes, and the plurality of first connection electrodes And an electronic circuit electrically connected to
The second chip is provided on the second upper surface of the substrate, and the upper surface of the second chip is connected to the lower surface of the first chip via a second connection electrode provided on the upper surface of the second chip. An optical circuit electrically connected to the electronic circuit via the second connection electrode;
The power supply circuit supplies a power supply voltage to the first chip and the second chip,
The control circuit controls the first chip and the second chip;
The optical circuit has at least a part of a light emitting circuit that converts a first electrical signal into a first optical signal and at least a part of a light receiving circuit that converts a second optical signal into a second electrical signal;
The electronic circuit outputs the first electric signal to the light emitting circuit, and receives the second electric signal from the light receiving circuit. A light-emitting element included in the light-emitting circuit and provided in the second chip;
A fourth connection electrode that is electrically connected to a part of the plurality of third connection electrodes and is not electrically connected to the first chip is provided on a first upper surface of the substrate;
6. The optical transceiver according to claim 5, wherein power of the light emitting element is supplied not through the first chip but through the plurality of third connection electrodes and the fifth connection electrode.

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