WO2021260890A1 - Optical module - Google Patents

Abstract

The present invention comprises: a light conversion element 10 having a plurality of bonding pads 11a, 11b, 11c that include a signaling bonding pad and are disposed in parallel; a wiring board 30 having a plurality of bonding pads which are disposed in parallel and face the plurality of bonding pads 31a, 31b, 31c in the light conversion element 10; and a wire group body 40 having a plurality of wires 41a, 41b, 41c which electrically connect the plurality of bonding pads 11a, 11b, 11c in the light conversion element 10 and the plurality of bonding pads 31a, 31b, 31c in the wiring board 30, respectively, and which are disposed in parallel, and non-conductive spacers 42a, 42b which are disposed between adjacent wires among the plurality of wires 41a, 41b, 41c and hold the adjacent wires.

Description

Optical module

This disclosure relates to an optical module provided with an optical conversion element and a wiring board.

Patent Document 1 discloses an optical modulator provided with a Machzenda type (MZ type) optical waveguide as one of the optical modules.
The optical modulator shown in Patent Document 1 has a signal wiring formed on the substrate and a terminal substrate between the signal wiring formed on the substrate on which the MZ type optical waveguide is integrated and arranged and the wiring formed on the relay substrate. It is electrically connected to the wiring formed in the above by wire bonding a wire such as a gold wire.

Further, an optical module which is an optical transmission module having an optical conversion element which is a semiconductor laser as a light source, and an optical receiver module which has an optical conversion element which is a light receiving element which converts the received signal light into an electric signal. Also in the module, the wiring board and the optical conversion element are electrically connected by wire bonding such as a gold wire.

Japanese Unexamined Patent Publication No. 2016-212130

Optical modules, which are optical communication devices in recent years, need to transmit high-speed electric signals of several tens of gigahertz due to the increase in communication capacity, and high-speed electric signals are also transmitted to wire-bonded wires. Therefore, in order to suppress the inductance of the wire, the length of the wire is shortened as much as possible, the variation in length among the plurality of wires is suppressed, and the signal wiring on the plurality of wires and the wiring board and the optical conversion element are used. It is desirable that the impedance be matched with the signal wiring of.

However, in the optical module shown in Patent Document 1, since a plurality of wires are electrically connected by simply wire bonding, the length of the wires varies among the plurality of wires. There is a problem that it is difficult to control the impedance of the wire due to the deviation of the bonding position and the change in the distance between the adjacent wires due to the aged deterioration of the wire shape due to its own weight, and the wire tends to become a mismatch point.

The present disclosure solves the above-mentioned problems, and an object thereof is to obtain an optical module in which the variation in length among a plurality of wires is suppressed.

The optical module according to the present disclosure includes an optical conversion element having a plurality of bonding pads arranged in parallel including a signal bonding pad, and a plurality of bonds arranged in parallel facing the plurality of bonding pads in the optical conversion element. Multiple wires arranged in parallel and adjacent wires in the plurality of wires that electrically connect the wiring board having the pads, each of the plurality of bonding pads in the optical conversion element, and each of the plurality of bonding pads in the wiring board. It comprises a wire assembly having a non-conductive spacer that is disposed between and holds adjacent wires.

According to the present disclosure, it is possible to suppress the variation in length among a plurality of wires to be bonded.

It is a schematic top view which shows the optical module which concerns on Embodiment 1. FIG. It is a schematic side view which shows the optical module which concerns on Embodiment 1. FIG. It is a perspective view which shows the wire group of the optical module which concerns on Embodiment 1. FIG. It is a schematic top view which shows the optical module which concerns on Embodiment 2. FIG. It is a schematic side view which shows the optical module which concerns on Embodiment 2. FIG. It is a perspective view which shows the wire group of the optical module which concerns on Embodiment 2. FIG. It is a schematic top view which shows the optical module which concerns on Embodiment 3. FIG. It is a schematic side view which shows the optical module which concerns on Embodiment 3. FIG. It is a perspective view which shows the wire group of the optical module which concerns on Embodiment 3. FIG. It is a schematic top view which shows the optical module which concerns on Embodiment 4. FIG. It is a schematic side view which shows the optical module which concerns on Embodiment 4. FIG. It is a perspective view which shows the wire group of the optical module which concerns on Embodiment 4. FIG.

Embodiment 1.
The optical module according to the first embodiment will be described with reference to FIGS. 1 to 3.
The optical module includes an optical conversion element 10, a driver IC 20, a wiring board 30, a first wire group 40, and a second wire group 50.

The light conversion element 10 is a Mach-Zehnder Modulator (MZ, hereinafter referred to as an MZ modulator element). The MZ modulator element 10 has a function of changing the phase of the incident light of the signal light emitted from the light source by an electric signal to generate a modulated signal light, and is, for example, a semiconductor which is superior in terms of compactness and low drive voltage. The MZ modulator element according to the above is used.

The MZ modulator element 10 is arranged in parallel on the surface of the substrate in the order of a modulation unit (MZM unit, not shown) and a ground line, a signal line, and a ground line corresponding to the modulation unit at equal intervals. It has a coplanar line (not shown). In the coplanar line, the line width of the signal line and the ground line and the distance between the signal line and the ground line are determined so that the impedance of the signal line and the ground line becomes a predetermined value (design value). Impedance matching is achieved because the ground wire, signal line, and ground wire wiring are arranged at equal intervals.
The line width of the signal line and the ground line is several tens of μm.

A high-speed electric signal of several tens of gigahels is transmitted to the signal line in the coplanar line for phase-modulating the signal light propagating in the optical waveguide in the modulation unit.
Generally, the modulator and the coplanar line have 2 channels or 4 channels, but in the first embodiment, one channel will be described for the sake of brevity.
When the MZ modulator element 10 is a differential drive type, the coplanar line is a coplanar line arranged in parallel at equal intervals in the order of ground line-signal line-signal line-ground line.

A ground terminal 11a, a signal input terminal 11b, and a ground terminal 11c are formed in parallel at equal intervals on a straight line at one end of the ground line, the signal line, and the ground line constituting the coplanar line, respectively.
The ground terminal 11a, the signal input terminal 11b, and the ground terminal 11c are bonding pads. The planar shape of each bonding pad is 100 μm × 100 μm, and the distance between them is set in consideration of the impedance of the coplanar line.

The MZ modulator element 10 is an optical conversion element having a plurality of bonding pads arranged in parallel at equal intervals on a straight line including a so-called signal bonding pad. In the first embodiment, the signal bonding pad is a signal input terminal 11b, and the plurality of bonding pads are a ground terminal 11a, a signal input terminal 11b, and a ground terminal 11c.

The driver IC 20 is a driver IC for amplifying an electric signal input to the MZ modulator element 10.
The driver IC 20 has a coplanar line (not shown) arranged in parallel at equal intervals in the order of ground line-signal line-ground line on the surface of the substrate corresponding to the coplanar line in the MZ modulator element 10. Also in the coplanar line in the driver IC 20, the line width of the signal line and the ground line and the distance between the signal line and the ground line are determined so that the impedance of the signal line and the ground line becomes a predetermined value (design value). Impedance matching is achieved because the ground wire, signal line, and ground wire wiring are arranged at equal intervals.
The line width of the signal line and the ground line is several tens of μm.
A high-speed electric signal of several tens of gigahertz for driving the MZ modulator element 10 is transmitted to the signal line of the coplanar line in the driver IC 20.

Further, a ground terminal 21a, a signal output terminal 21b, and a ground terminal 21c are formed in parallel at equal intervals on a straight line at one end of the ground line, the signal line, and the ground line constituting the coplanar line in the driver IC 20, respectively.
The ground terminal 21a, the signal output terminal 21b, and the ground terminal 21c are bonding pads, and their respective planar shapes are 100 μm × 100 μm, and their respective intervals are set in consideration of the impedance of the coplanar line.

The driver IC 20 has a plurality of bonding pads arranged in parallel at equal intervals on a straight line including a bonding pad for signals. In the first embodiment, the signal bonding pad is a signal output terminal 21b, and the plurality of bonding pads are a ground terminal 21a, a signal output terminal 21b, and a ground terminal 21c.

The wiring board 30 includes a plurality of bonding buds of the MZ modulator element 10, that is, a ground terminal 11a, a signal input terminal 11b, and a ground terminal 11c, and a plurality of bonding buds of the driver IC 20, that is, a ground terminal 21a and a signal output. The terminal 21b and the ground terminal 21c are electrically connected.

The wiring board 30 is arranged in parallel at equal intervals in the order of ground wire-signal line-ground wire formed on the surface of a substrate made of a ceramic material such as alumina or aluminum nitride (AlN) or glass such as quartz. It has a coplanar line (not shown). Also in the coplanar line in the wiring board 30, the line width of the signal line and the ground line and the distance between the signal line and the ground line are determined so that the impedance of the signal line and the ground line becomes a predetermined value (design value). Impedance matching is achieved because the ground wire, signal line, and ground wire wiring are arranged at equal intervals.
The line width of the signal line and the ground line is several tens of μm.
The signal line of the coplanar line in the wiring board 30 transmits a high-speed electric signal of several tens of gigahertz from the signal output terminal 21b of the driver IC 20 to the signal input terminal 11b of the MZ modulator element 10.

A ground terminal 31a, a signal output terminal 31b, and a ground terminal 31c are formed in parallel at equal intervals on a straight line at one end of the ground line, the signal line, and the ground line constituting the coplanar line in the wiring board 30, respectively.
The ground terminal 31a, the signal output terminal 31b, and the ground terminal 31c are bonding pads, and their respective planar shapes are 100 μm × 100 μm, and their respective intervals are set in consideration of the impedance of the coplanar line.

A ground terminal 32a, a signal input terminal 32b, and a ground terminal 32c are formed in parallel at equal intervals on a straight line at the other ends of the ground line, the signal line, and the ground line constituting the coplanar line in the wiring board 30, respectively.
The ground terminal 32a, the signal input terminal 32b, and the ground terminal 32c are bonding pads, and their respective planar shapes are 100 μm × 100 μm, and their respective intervals are set in consideration of the impedance of the coplanar line.

The wiring board 30 faces the ground terminal 31a, the signal output terminal 31b, and the ground terminal 31c of the MZ modulator element 10 with respect to the ground terminal 11a, the signal input terminal 11b, and the ground terminal 11c, respectively. Will be placed.
The wiring board 30 is arranged with respect to the driver IC 20 so that the ground terminal 32a, the signal input terminal 32b, and the ground terminal 32c each face the ground terminal 21a, the signal output terminal 21b, and the ground terminal 21c of the driver IC 20.

That is, the wiring board 30 electrically connects the plurality of bonding buds in the optical conversion element 10 and the plurality of bonding buds in the driver IC 20, respectively.
The wiring board 30 has a plurality of bonding pads arranged in parallel at equal intervals in a straight line facing the plurality of bonding pads in the optical conversion element 10. In the first embodiment, the plurality of bonding pads are a ground terminal 31a, a signal output terminal 31b, and a ground terminal 31c.
Further, the wiring board 30 has a plurality of bonding pads arranged in parallel at equal intervals in a straight line facing the plurality of bonding pads in the driver IC 20. In the first embodiment, the plurality of bonding pads are a ground terminal 32a, a signal input terminal 32b, and a ground terminal 32c.

One end of the first wire group 40 is electrically connected to each of a plurality of bonding buds in the MZ modulator element 10, that is, the ground terminal 11a, the signal input terminal 11b, and the ground terminal 11c, and the other end is the wiring board 30. Is electrically connected to each of the plurality of bonding pads in the above, that is, the ground terminal 31a, the signal output terminal 31b, and the ground terminal 31c.
One end of the second wire group 50 is electrically connected to each of the plurality of bonding buds in the driver IC 20, that is, the ground terminal 21a, the signal output terminal 21b, and the ground terminal 21c, and the other end is a plurality of wiring boards 30. It is electrically connected to the bonding pad, that is, the ground terminal 32a, the signal input terminal 32b, and the ground terminal 32c.

That is, a transmission path of an electric signal from the plurality of bonding buds in the driver IC 20 to the plurality of bonding pads on the input side in the wiring board 30 via the second wire group 50 is formed, and the transmission path on the output side in the wiring board 30 is formed. A transmission path for electrical signals from the plurality of bonding pads to the plurality of bonding buds in the MZ modulator element 10 via the first wire group 40 is formed.

As shown in FIG. 3, the first wire group 40 and the second wire group 50 are arranged in parallel at equal intervals, and a plurality of wires 41a to 41c and 51a to 51c having the same length and thickness are arranged in parallel. , And the non-conductive spacers 42a / 42b, 52a / 52b, and the plurality of wires 41a, which are closely arranged between the adjacent wires in the plurality of wires 41a to 41c and 51a to 51c and hold the adjacent wires. It has side surface holders 42c / 42d and 52c / 52d arranged in close contact with the wires located on both side surfaces in ~ 41c and 51a to 51c.

Each of the plurality of wires 41a to 41c and 51a to 51c is a wire such as a gold wire, an aluminum wire or a copper wire. The cross-sectional shape of each of the plurality of wires 41a to 41c and 51a to 51c is a quadrangular shape having a side of several tens of μm or a circular shape having a diameter of several tens of μm.
The spacers 42a / 42b, 52a / 52b and the side surface holders 42c / 42d, 52c / 52d are non-conductive resins made of an insulating material. The materials of the spacers 42a / 42b, 52a / 52b and the side surface holders 42c / 42d, 52c / 52d are preferably high resin adhesives having shape variability after curing.

In the first wire group 40, three wires 41a, 41b, 41c having the same length and thickness are arranged in parallel at equal intervals, and between the wires 41a and 41b, and between the wires 41b and 41c. , The outer surface of the wire 41a and the outer surface of the wire 41c are poured with a resin adhesive having high shape variability after curing, and the resin adhesive is cured to harden the three wires 41a, 41b, 41c at once. To manufacture.

Since the first wire group 40 is manufactured by bundling three wires 41a, 41b, 41c at equal intervals with a resin adhesive having high shape variability after curing, the first wire group 40 is manufactured as a whole. It has flexibility in the front and back directions, is easy to bend in the front and back directions, and has a structure that is resistant to some twisting.

The cured resin adhesive between the wire 41a and the wire 41b adheres to the spacer 42a, and the cured resin adhesive between the wire 41b and the wire 41c adheres to the spacer 42b and cures to the outer surface of the wire 41a. The resin adhesive obtained is attached to the side surface holder 42c, and the resin adhesive cured by adhering to the outer surface of the wire 41c is the side surface holder 42d.
As a result, the wires 41a, 41b, 41c, the spacers 42a, 42b, and the side surface holders 42c, 42d are integrated and treated as one wire group.

In the first wire group 40, the distance between the wire 41a and the wire 41b and the distance between the wire 41b and the wire 41c are desired values over the entire length by the spacer 42a and the spacer 42b having the same width over the entire length. It is always kept at (design value). As a result, the impedances of the wire 41a, the wire 41b, and the wire 41c can be kept constant, the wires 41a, the wire 41b, and the wire 41c do not become impedance mismatch points, and deterioration of transmission characteristics in a high-speed electric signal is suppressed. can.

The entire surface and back surface of the wires 41a, 41b, and 41c are exposed.
The front surface and the back surface of the wires 41a, 41b, and 41c may be covered with a resin adhesive so that both ends to be bonded are exposed.

As shown in FIGS. 1 and 2, in the first wire group 40, one end of the back surface of the wire 41a, the wire 41b, and the wire 41c is the ground terminal 11a, the signal input terminal 11b, and the ground terminal 11c of the MZ modulator element 10, respectively. And are joined using a wedge bonder. That is, heat and ultrasonic vibration are applied to the upper and lower surfaces of one end of the wire 41a, the wire 41b, and the wire 41c, and one end of the wire 41a, the wire 41b, and the wire 41c is crushed while the ground terminal 11a in the MZ modulator element 10 is crushed. It is joined to each of the surfaces of the signal input terminal 11b and the ground terminal 11c.

On the other hand, the other end of the back surface of the wire 41a, the wire 41b, and the wire 41c is joined to the ground terminal 31a, the signal output terminal 31b, and the ground terminal 31c of the wiring board 30 by using a wedge bonder. That is, heat and ultrasonic vibration are applied to the upper and lower surfaces of the other ends of the wire 41a, the wire 41b, and the wire 41c, and the other ends of the wire 41a, the wire 41b, and the wire 41c are crushed while the ground terminal 31a on the wiring board 30 is crushed. It is joined to each of the surfaces of the signal output terminal 31b and the ground terminal 31c.

Since the first wire group 40 is easily bent in the front and back directions and has a strong flexibility against twisting, the ground terminal 11a, the signal input terminal 11b, the ground terminal 11c, and the ground in the wiring board 30 of the MZ modulator element 10 are respectively. Even if there is a slight relative positional deviation between the terminal 31a, the signal output terminal 31b, and the ground terminal 31c, the wire 41a, the wire 41b, and the wire can be adjusted by adjusting the bending condition of the first wire group 40. Since the lengths of the 41c are the same, the wire lengths of the wire 41a, the wire 41b, and the wire 41c do not vary, and the ground terminal 11a, the signal input terminal 11b, and the ground terminal 11c of the MZ modulator element 10 are wired. It is possible to absorb the relative positional deviation between the ground terminal 31a, the signal output terminal 31b, and the ground terminal 31c on the substrate 30.

In the second wire group 50, three wires 51a, 51b, 51c having the same length and thickness are arranged in parallel at equal intervals, and between the wires 51a and 51b, and between the wires 51b and 51c. , A resin adhesive having high shape variability after curing is poured into the outer surface of the wire 51a and the outer surface of the wire 51c, and the resin adhesive is cured to harden the three wires 51a, 51b, 51c at once. To manufacture.

Since the second wire group 50 is manufactured by bundling three wires 51a, 51b, 51c at equal intervals with a resin adhesive having high shape variability after curing, the second wire group 50 is manufactured as a whole. It has flexibility in the front and back directions, is easy to bend in the front and back directions, and has a structure that is resistant to some twisting.

The cured resin adhesive between the wire 51a and the wire 51b adheres to the spacer 52a, and the cured resin adhesive between the wire 51b and the wire 51c adheres to the spacer 52b and cures to the outer surface of the wire 51a. The resin adhesive obtained is attached to the side surface holder 52c, and the resin adhesive cured by adhering to the outer surface of the wire 51c is the side surface holder 52d.
As a result, the wires 51a, 51b, 51c, the spacers 52a, 52b, and the side surface holders 52c, 52d are integrated and treated as one wire group.

In the second wire group 50, the distance between the wire 51a and the wire 51b and the distance between the wire 51b and the wire 51c are desired values over the entire length by the spacer 52a and the spacer 52b having the same width over the entire length. It is always kept at (design value). As a result, the impedances of the wire 51a, the wire 51b, and the wire 51c can be kept constant, the wires 51a, the wire 51b, and the wire 51c do not become impedance mismatch points, and deterioration of transmission characteristics in a high-speed electric signal is suppressed. can.

The entire surface and back surface of the wires 51a, 51b, and 51c are exposed.
The front surface and the back surface of the wires 51a, 51b, 51c may be covered with a resin adhesive, and both ends to be bonded may be exposed.

As shown in FIGS. 1 and 2, in the second wire group 50, one end of the back surface of the wire 51a, the wire 51b, and the wire 51c is a ground terminal 21a, a signal output terminal 21b, a ground terminal 21c, and a wedge bonder in the driver IC 20. Is joined using. That is, heat and ultrasonic vibration are applied to the upper and lower surfaces of one end of the wire 51a, the wire 51b, and the wire 51c, and one end of the wire 51a, the wire 51b, and the wire 51c is crushed while the ground terminal 21a and the signal output terminal 21b of the driver IC 20 are crushed. , Joined to each surface of the ground terminal 21c.

On the other hand, the other end of the back surface of the wire 51a, the wire 51b, and the wire 51c is joined to the ground terminal 32a, the signal input terminal 32b, and the ground terminal 32c of the wiring board 30 by using a wedge bonder. That is, heat and ultrasonic vibration are applied to the upper and lower surfaces of the other ends of the wire 51a, the wire 51b, and the wire 51c, and the other ends of the wire 51a, the wire 51b, and the wire 51c are crushed while the ground terminal 32a on the wiring board 30 is crushed. It is joined to each of the surfaces of the signal input terminal 32b and the ground terminal 32c.

Since the second wire group 50 is easily bent in the front and back directions and has a strong flexibility against twisting, the ground terminal 21a, the signal output terminal 21b, the ground terminal 21c in the driver IC 20, and the ground terminal 32a in the wiring board 30. Even if there is a slight relative displacement between the signal input terminal 32b and the ground terminal 32c, the lengths of the wire 51a, wire 51b, and wire 51c can be adjusted by adjusting the bending condition of the second wire group 50. Since the wires are the same, the wire lengths of the wires 51a, 51b, and 51c do not vary, and the ground terminal 21a, the signal output terminal 21b, and the ground terminal 21c of the driver IC 20 and the ground terminal 32a of the wiring board 30 are the same. , The relative positional deviation with each of the signal input terminal 32b and the ground terminal 32c can be absorbed.

As described above, in the optical module according to the first embodiment, the plurality of bonding buds 11a, 11b, 11c in the MZ modulator element 10 and the plurality of bonding pads 31a, 31b, 31c in the wiring substrate 30 are electrically connected. The first wire group 40 to be connected is adjacent to a plurality of wires 41a, 41b, 41c arranged in parallel, and a non-conductive spacer 42a arranged between the adjacent wires 41a and 41b. Since the non-conductive spacer 42b arranged between the wires 41b and the wires 41c is provided, it is possible to suppress the variation in length among the plurality of wires 41a, 41b, 41c.

In particular, since the first wire group 40 has flexibility, between each of the plurality of bonding buds 11a, 11b, 11c in the MZ modulator element 10 and each of the plurality of bonding pads 31a, 31b, 31c in the wiring substrate 30. Even if there is a relative misalignment between the wires 41a, 41b, and 41c between the plurality of bonding buds in the MZ modulator element 10 and the plurality of bonding pads in the wiring board 30, the wire lengths vary. It does not occur, the mismatch of the impedance in the wires 41a, 41b, and 41c can be prevented, and there is an effect that the deterioration of the transmission characteristics of the high-speed electric signal can be suppressed.

Further, the optical module according to the first embodiment is a second wire for electrically connecting a plurality of bonding buds 21a, 21b, 21c in the driver IC 20 and a plurality of bonding pads 32a, 32b, 32c in the wiring board 30. The group 50 is placed between a plurality of wires 51a, 51b, 51c arranged in parallel, a non-conductive spacer 52a arranged between the adjacent wires 51a and 51b, and between the adjacent wires 51b and 51c. Since the non-conductive spacer 52b to be arranged is provided, it is possible to suppress the variation in length among the plurality of wires 51a, 51b, 51c.

In particular, since the second wire group 50 has flexibility, it is relative to each of the plurality of bonding buds 21a, 21b, 21c in the driver IC 20 and each of the plurality of bonding pads 32a, 32b, 32c in the wiring board 30. Wires in wires 51a, 51b, 51c between the plurality of bonding buds 21a, 21b, 21c in the driver IC 20 and the plurality of bonding pads 32a, 32b, 32c in the wiring board 30, even if the misalignment occurs. There is no variation in length, impedance mismatch in the wires 51a, 51b, and 51c can be prevented, and there is an effect of suppressing deterioration of transmission characteristics of high-speed electric signals.

Embodiment 2.
The optical module according to the second embodiment will be described with reference to FIGS. 4 to 6.
The optical module according to the first embodiment uses a Machzenda modulator element as an optical conversion element, whereas the optical module according to the second embodiment uses a light emitting element and light which are semiconductor lasers for optical communication as an optical conversion element. It uses at least one element of a light receiving element which is a photodiode for communication.
In the following description, a light conversion element having both a light emitting element and a light receiving element will be described.
That is, the optical module includes an optical conversion element 60 having both a semiconductor laser and a light receiving element, a wiring substrate 70, and a wire group 80.

The optical conversion element 60 receives a semiconductor laser that emits laser light controlled by a drive signal consisting of a high-speed electric signal and a part of the laser light emitted from the semiconductor laser, and determines the intensity of the received laser light. It has a light receiving element that outputs a control signal for controlling the drive signal of the semiconductor laser accordingly.

The optical conversion element 60 is formed on the surface of the substrate between an input signal line for transmitting a drive signal to a semiconductor laser, an output signal line for transmitting a control signal from a light receiving element, and an input signal line and an output signal line. Has a ground line to avoid placement. The line widths of the input signal line, the output signal line, and the ground line are several tens of μm.

A signal input terminal 61a, a ground terminal 61b, and a signal output terminal 61c are formed in parallel on one end of an input signal line, an output signal line, and a ground line, respectively.
The signal input terminal 61a, the ground terminal 61b, and the signal output terminal 61c are bonding pads, and their respective planar shapes are 100 μm × 100 μm.

The optical conversion element 60 is an optical conversion element having a plurality of bonding pads arranged in parallel at equal intervals on a straight line including a so-called signal bonding pad. In the second embodiment, the signal bonding pad is a signal input terminal 61a, and the plurality of bonding pads are a signal input terminal 61a, a ground terminal 61b, and a signal output terminal 61c.

The wiring board 70 has a plurality of bonding buds of the optical conversion element 60, that is, a plurality of bonding buds electrically connected to the signal input terminal 61a, the ground terminal 61b, and the signal output terminal 61c, that is, the signal output terminal 71a. , Has a ground terminal 71b and a signal input terminal 71c.

The wiring substrate 70 is arranged in parallel in the order of signal output line-ground wire-signal input line formed on the surface of a substrate made of a ceramic material such as alumina or aluminum nitride (AlN) or glass such as quartz. It has a signal output line, a ground line, and a signal input line (not shown). The line widths of the signal output line, the ground line, and the signal input line are several tens of μm.

A signal output terminal 71a, a ground terminal 71b, and a signal input terminal 71c are formed in parallel on one end of a signal output line, a ground line, and a signal input line in the wiring board 70, respectively.
The signal output terminal 71a, the ground terminal 71b, and the signal input terminal 71c are bonding pads, and their respective planar shapes are 100 μm × 100 μm.

The wiring board 70 faces the signal output terminal 71a, the ground terminal 71b, and the signal input terminal 71c with respect to the optical conversion element 60, respectively, facing the signal input terminal 61a, the ground terminal 61b, and the signal output terminal 61c in the optical conversion element 60. Is placed.
That is, the wiring board 70 has a plurality of bonding pads arranged in parallel in a straight line facing the plurality of bonding pads in the optical conversion element 60. In the second embodiment, the plurality of bonding pads are a signal input terminal 61a, a ground terminal 61b, and a signal output terminal 61c.

One end of the wire group 80 is electrically connected to each of a plurality of bonding buds in the optical conversion element 60, that is, a signal input terminal 61a, a ground terminal 61b, and a signal output terminal 61c, and the other end is a plurality of wires in the wiring board 70. It is electrically connected to the bonding pad, that is, the signal output terminal 71a, the ground terminal 71b, and the signal input terminal 71c, respectively.
That is, a transmission path of an electric signal that reaches the plurality of bonding buds in the optical conversion element 60 from the plurality of bonding pads on the output side of the wiring board 70 via the wire group 80 is formed.

As shown in FIG. 6, the wire group 80 is arranged in parallel and closely between the plurality of wires 81a to 81c having the same length and thickness and the adjacent wires in the plurality of wires 81a to 81c. It has non-conductive spacers 82a, 82b that are arranged and hold the adjacent wires, as well as side surface holders 82c, 82d that are closely arranged to the wires located on both sides of the plurality of wires 81a-81c.

Each of the plurality of wires 81a to 81c is a wire such as a gold wire, an aluminum wire, or a copper wire. The cross-sectional shape of each of the plurality of wires 81a to 81c is a quadrangular shape having a side of several tens of μm or a circular shape having a diameter of several tens of μm.
The spacers 82a and 82b and the side surface holders 82c and 82d are non-conductive resins made of an insulating material. The materials of the spacers 82a and 82b and the side surface holders 82c and 82d are preferably high resin adhesives having shape variability after curing.

In the wire group 80, three wires 81a, 81b, 81c having the same length and thickness are arranged in parallel, and the outer surface of the wire 81a is arranged between the wire 81a and the wire 81b, between the wire 81b and the wire 81c, and the outer surface of the wire 81a. The three wires 81a, 81b, 81c are collectively hardened and manufactured by pouring a resin adhesive having high shape variability after curing into the outer surface of the wire 81c and curing the resin adhesive.
Since the wire group 80 is manufactured by bundling three wires 81a, 81b, 81c with a resin adhesive having high shape variability after curing, the wire group 80 has flexibility in the front and back directions as a whole. It has a structure that is easy to bend in the front and back directions and is resistant to some twisting.

The cured resin adhesive between the wire 81a and the wire 81b adheres to the spacer 82a, and the cured resin adhesive between the wire 81b and the wire 81c adheres to the spacer 82b and cures to the outer surface of the wire 81a. The resin adhesive obtained is attached to the side surface holder 82c, and the resin adhesive cured by adhering to the outer surface of the wire 81c becomes the side surface holder 82d.
As a result, the wires 81a, 81b, 81c, the spacers 82a, 82b, and the side surface holders 82c, 82d are integrated and treated as one wire group.

In the wire group 80, the distance between the wire 81a and the wire 81b and the distance between the wire 81b and the wire 81c are desired values (design values) over the entire length by the spacer 82a and the spacer 82b having the same width over the entire length. ) Is always kept. As a result, deterioration of transmission characteristics in high-speed electric signals can be suppressed.
The entire surface and back surface of the wires 81a, 81b, and 81c are exposed.
The front surface and the back surface of the wires 81a, 81b, 81c may be covered with a resin adhesive, and both ends to be bonded may be exposed.

As shown in FIGS. 4 and 5, in the wire group 80, one end of the back surface of the wire 81a, the wire 81b, and the wire 81c is a signal input terminal 61a, a ground terminal 61b, a signal output terminal 61c, and a wedge bonder of the optical conversion element 60. Is joined using. That is, heat and ultrasonic vibration are applied to the upper and lower surfaces of one end of the wire 81a, the wire 81b, and the wire 81c, and the signal input terminal 61a in the optical conversion element 60 is crushed while one end of the wire 81a, the wire 81b, and the wire 81c is crushed. It is joined to each of the surfaces of the ground terminal 61b and the signal output terminal 61c.

On the other hand, the other end of the back surface of the wire 81a, the wire 81b, and the wire 81c is joined to each of the signal output terminal 71a, the ground terminal 71b, and the signal input terminal 71c of the wiring board 70 by using a wedge bonder. That is, heat and ultrasonic vibration are applied to the upper and lower surfaces of the other ends of the wires 81a, 81b, and 81c, and the other ends of the wires 81a, 81b, and 81c are crushed while the signal output terminals 71a on the wiring board 70 are crushed. , Is joined to the surface of the ground terminal 71b and the signal input terminal 71c, respectively.

Since the wire group 80 is easily bent in the front and back directions and has strong flexibility against twisting, the signal input terminal 61a, the ground terminal 61b, the signal output terminal 61c in the optical conversion element 60, and the signal output terminal 71a in the wiring board 70, respectively. There is a margin in bonding and bonding with each of the ground terminal 71b and the signal input terminal 71c.

As described above, in the optical module according to the second embodiment, the plurality of bonding pads 61a, 61b, 61c in the optical conversion element 60 and the plurality of bonding pads 71a, 71b, 71c in the wiring board 70 are electrically connected. The wire group 80 to be connected includes a plurality of wires 81a, 81b, 81c arranged in parallel, a non-conductive spacer 82a arranged between the adjacent wires 81a and 81b, and the adjacent wires 81b and 81c. Since it is assumed that the non-conductive spacer 82b is arranged between the wires 81a, it is possible to suppress the variation in length among the plurality of wires 81a, 81b, 81c.

In particular, since the wire group 80 has flexibility, it is excellent in bonding bonding between each of the plurality of bonding pads 61a, 61b, 61c in the optical conversion element 60 and each of the plurality of bonding pads 71a, 71b, 71c in the wiring board 70. Can have a degree.

Although the optical module according to the second embodiment described above has both a light emitting element which is a semiconductor laser for optical communication and a light receiving element which is a photodiode for optical communication as an optical conversion element, it has been described. Even in an optical module that is an optical transmission module equipped with a semiconductor laser that serves as a light source as an optical conversion element, or an optical reception module that has a light receiving element that converts received signal light into an electric signal, the wiring board and the optical conversion element The wire group 80 shown in FIG. 6 can be used for the electrical connection between the two.
At this time, although the electric signals transmitted to the plurality of wires in the wire group 80 are different in the optical transmission module and the optical reception module, the structure is the same.

Embodiment 3.
The optical module according to the third embodiment will be described with reference to FIGS. 7 to 9.
In the optical module according to the third embodiment, the first wire group 40 and the second wire group 50 hold spacers and side surfaces at both ends of each of the plurality of wires with respect to the optical module according to the first embodiment. The only difference is that it has a bonding portion that protrudes from the end face of the body, and is otherwise the same.
Therefore, the first wire group 40 and the second wire group 50 will be mainly described below.
In FIGS. 7 to 9, the same reference numerals as those given in FIGS. 1 to 3 indicate the same or corresponding portions.

As shown in FIG. 9, the first wire group 40 and the second wire group 50 are arranged in parallel at equal intervals, and a plurality of wires 41a to 41c and 51a to 51c having the same length and thickness are arranged in parallel. , And the non-conductive spacers 42a / 42b, 52a / 52b, and the plurality of wires 41a, which are closely arranged between the adjacent wires in the plurality of wires 41a to 41c and 51a to 51c and hold the adjacent wires. It has side surface holders 42c / 42d and 52c / 52d arranged in close contact with the wires located on both side surfaces in ~ 41c and 51a to 51c.

The lengths of the spacers 42a / 42b, 52a / 52b and the side surface holders 42c / 42d, 52c / 52d are shorter than the lengths of the wires 41a to 41c and 51a to 51c. At both ends of each of the plurality of wires 41a to 41c and 51a to 51c, the portions protruding from the end faces of the spacers 42a / 42b, 52a / 52b and the side surface holders 42c / 42d, 52c / 52d are the bonding portions 41a1 to 41c1, 41a2 to 41c2, 51a1 to 51c1, 51a2 to 51c2.

In the first wire group 40, three wires 41a, 41b, 41c having the same length and thickness are arranged in parallel at equal intervals, and between the wires 41a and 41b, and between the wires 41b and 41c. The entire periphery of the bonding portions 41a1 to 41c1 and 41a2 to 41c2 is exposed on the outer surface of the wire 41a and the outer surface of the wire 41c, and a resin adhesive having high shape variability after curing is poured into the bonding portions. By curing the agent, the three wires 41a, 41b, and 41c are collectively hardened and manufactured.
The entire surface and back surface of the wires 41a, 41b, and 41c are exposed.
The front surface and the back surface of the wires 41a, 41b, 41c excluding the bonding portions 41a1 to 41c1 and 41a2 to 41c2 may be covered with a resin adhesive.

In the second wire group 50, three wires 51a, 51b, 51c having the same length and thickness are arranged in parallel at equal intervals, and between the wires 51a and 51b, and between the wires 51b and 51c. The entire periphery of the bonding portions 51a1 to 51c1 and 51a2 to 51c2 is exposed on the outer surface of the wire 51a and the outer surface of the wire 51c, and a resin adhesive having high shape variability after curing is poured into the bonding portions. By curing the agent, the three wires 51a, 51b, and 51c are collectively hardened and manufactured.
The entire surface and back surface of the wires 51a, 51b, and 51c are exposed.
The front surface and the back surface of the wires 51a, 51b, 51c excluding the bonding portions 51a1 to 51c1 and 51a2 to 51c2 may be covered with a resin adhesive.

As shown in FIGS. 7 and 8, in the first wire group 40, the back surfaces of the bonding portions 41a1, 41b1 and 41c1 in the wires 41a, 41b and 41c are the ground terminal 11a and the signal input terminal in the MZ modulator element 10. It is joined to each of 11b and the ground terminal 11c using a wedge bonder. That is, heat and ultrasonic vibration are applied to the upper and lower surfaces of the bonding portions 41a1, 41b1 and 41c1 of the wires 41a, 41b and 41c, and the bonding portions 41a1, 41b1 and 41c1 of the wires 41a, 41b and 41c are crushed. However, they are joined to the surfaces of the ground terminal 11a, the signal input terminal 11b, and the ground terminal 11c in the MZ modulator element 10.

On the other hand, the back surfaces of the bonding portions 41a2, 41b2, and 41c2 of the wire 41a, the wire 41b, and the wire 41c are joined to the ground terminal 31a, the signal output terminal 31b, and the ground terminal 31c of the wiring board 30 by using a wedge bonder. That is, heat and ultrasonic vibration are applied to the upper and lower surfaces of the bonding portions 41a2, 41b2, and 41c2 of the wires 41a, 41b, and the wire 41c, and the bonding portions 41a2, 41b2, and 41c2 of the wires 41a, 41b, and the wire 41c are crushed. However, they are joined to the surfaces of the ground terminal 31a, the signal output terminal 31b, and the ground terminal 31c on the wiring board 30.

As shown in FIGS. 7 and 8, in the second wire group 50, the back surfaces of the bonding portions 51a1, 51b1, 51c1 in the wires 51a, the wire 51b, and the wire 51c are the ground terminal 21a, the signal output terminal 21b, and the ground in the driver IC 20. It is joined to each of the terminals 21c using a wedge bonder. That is, heat and ultrasonic vibration are applied to the upper and lower surfaces of the bonding portions 51a1, 51b1 and 51c1 of the wires 51a, 51b and 51c, and the bonding portions 51a1, 51b1 and 51c1 of the wires 51a, 51b and 51c are crushed. However, it is joined to each of the surfaces of the ground terminal 21a, the signal output terminal 21b, and the ground terminal 21c in the driver IC 20.

On the other hand, the back surfaces of the bonding portions 51a2, 51b2, and 51c2 of the wire 51a, the wire 51b, and the wire 51c are joined to the ground terminal 32a, the signal input terminal 32b, and the ground terminal 32c of the wiring board 30 by using a wedge bonder. That is, heat and ultrasonic vibration are applied to the upper and lower surfaces of the bonding portions 51a2, 51b2, and 51c2 of the wires 51a, 51b, and the wire 51c, and the bonding portions 51a2, 51b2, and 51c2 of the wires 51a, 51b, and the wire 51c are crushed. However, they are joined to the surfaces of the ground terminal 32a, the signal input terminal 32b, and the ground terminal 32c on the wiring board 30.

As described above, the optical module according to the third embodiment has the same effect as the optical module according to the first embodiment, and also has wires 41a, wire 41b, wires 41c, and wires 51a, wires 51b, and wires. It is possible to increase the bonding strength of the bonding portion while maintaining the impedance of 51c at the design value.

Embodiment 4.
The optical module according to the fourth embodiment will be described with reference to FIGS. 10 to 12.
In the optical module according to the fourth embodiment, the spacers 42a, 42b, 52a, 52b of the first wire group 40 and the second wire group 50 have a plurality of wires with respect to the optical module according to the third embodiment. The difference is that the first spacer portion arranged on one end side and the second spacer portion arranged with a gap from the first spacer portion are provided on the other end side of the plurality of wires. It is the same in terms of points.
Therefore, the first wire group 40 and the second wire group 50 will be mainly described below.
In addition, in FIGS. 10 to 12, the same reference numerals as those attached to FIGS. 7 to 9 indicate the same or corresponding portions.

As shown in FIG. 12, each of the first wire group 40 and the second wire group 50 is arranged in parallel at equal intervals, and a plurality of wires 41a to 41c and 51a to 51c having the same length and thickness are arranged in parallel. , And the non-conductive first spacer portions 42a1, 42b1, 52a1, 52b1 and the first, which are closely arranged between the adjacent wires in the plurality of wires 41a to 41c and 51a to 51c and hold the adjacent wires. The second spacer portions 42a2, 42b2, 52a2, 52b2 arranged with a gap from the spacer portions 42a1, 42b1, 52a1, 52b1 of 1, and the wires located on both side surfaces of the plurality of wires 41a to 41c, 51a to 51c. A second side surface portion arranged with a gap between the first side surface holders 42c1 and 42d1 and 52c1 and 52d1 and the first side surface holders 42c1 and 42d1 and 52c1 and 52d1 arranged closely to each other. It has a holder 42c2 ・ 42d2 and 52c2 ・ 52d2.

In the first wire group 40, three wires 41a, 41b, 41c having the same length and thickness are arranged in parallel at equal intervals, and between the wires 41a and 41b, and between the wires 41b and 41c. , The outer surface of the wire 41a and the outer surface of the wire 41c are exposed to the entire circumference of the portion to be the bonding portions 41a1 to 41c1 and 41a2 to 41c2 and the entire circumference of the gap portion in the wires 41a, 41b and 41c after curing. By pouring a resin adhesive having high shape variability and curing the resin adhesive, the three wires 41a, 41b, and 41c are collectively hardened and manufactured.
The entire surface and back surface of the wires 41a, 41b, and 41c are exposed.
The front surface and the back surface of the wires 41a, 41b, 41c excluding the gaps in the bonding portions 41a1 to 41c1, 41a2 to 41c2 and the wires 41a, 41b, 41c may be covered with a resin adhesive.

In the second wire group 50, three wires 51a, 51b, 51c having the same length and thickness are arranged in parallel at equal intervals, and between the wires 51a and 51b, and between the wires 51b and 51c. , The outer surface of the wire 51a and the outer surface of the wire 51c are exposed to the entire circumference of the portion to be the bonding portions 51a1 to 51c1 and 51a2 to 51c2 and the entire circumference of the gap portion in the wires 51a, 51b and 51c, and after curing. By pouring a resin adhesive having high shape variability and curing the resin adhesive, the three wires 51a, 51b, and 51c are collectively hardened and manufactured.
The entire surface and back surface of the wires 51a, 51b, and 51c are exposed.
The front surface and the back surface of the wires 51a, 51b, 51c excluding the gaps in the bonding portions 51a1 to 51c1, 51a2 to 51c2 and the wires 51a, 51b, 51c may be covered with a resin adhesive.

In addition, although the spacer is divided into two parts, a first spacer part and a second spacer part, it may be further divided, and it may be a spacer having a plurality of divided spacer parts. ..

As described above, the optical module according to the fourth embodiment has the same effect as the optical module according to the third embodiment, and the spacers are the first spacer portions 42a1 ・ 42b1, 52a1.52b1 and the second. The spacer portions 42a2, 42b2, 52a2, 52b2 are divided with a gap, and the side surface portion holders are the first side surface portion holders 42c1 and 42c2, 52c1 and 52c2, and the second side surface portion holders 42d1 and 42d2. Since the 52d1 and 52d2 are divided with a gap, both the first wire group 40 and the second wire group 50 are the first wire group 40 and the second wire group 50 in the optical module according to the third embodiment. Since the wire 41a to 41c and the wire 41a to 51c are maintained at the design values, the mounting becomes easy because the wire 41a to 41c and the wire 41a to 51c are more flexible and the shape can be easily changed.

Further, the gaps between the wires 41a to 41c and 51a to 51c located in the gap between the first spacer portions 42a1, 42b1, 52a1 and 52b1 and the second spacer portions 42a2 and 42b2, 52a2 and 52b2 are covered with the spacer member. Since it is not broken, the thermal conductivity is lower than the portion where the first spacer portions 42a1, 42b1, 52a1 and 52b1 and the second spacer portions 42a2, 42b2 and 52a2 and 52b2 are located. It is possible to suppress heat inflow between the members via the 42b1 and 52a1 and 52b1 and the second spacer portions 42a2 and 42b2 and 52a2 and 52b2.

In the optical module according to the second embodiment, the wire group 80 may be replaced with the wire group 40 in the optical module according to the third embodiment or the wire group 40 in the optical module according to the fourth embodiment.

It is possible to freely combine each embodiment, modify any component of each embodiment, or omit any component in each embodiment.

10, 60 optical conversion element, 20 driver IC, 30, 70 wiring board, 40 first wire group, 50 second wire group, 80 wire group, 11a, 11b, 11c, 21a, 21b, 21c, 31a, 31b , 31c, 32a, 32b, 32c, 61a, 61b, 6c, 71a, 71b, 71c Bonding Pads, 41a, 41b, 41c, 51a, 51b, 51c Wires, 41a1, 41b1, 41c1, 51a1, 51b1, 51c1, 41a2, 41b2, 41c2, 51a2, 51b2, 51c2 Bonding part, 42a, 42b, 52a, 52b spacer, 42a1, 42b1, 52a1, 52b1 First spacer part, 42a2, 42b2, 52a2, 52b2 Second spacer part.

Claims (7)

1. An optical conversion element having a plurality of bonding pads arranged in parallel including a bonding pad for a signal,
   A wiring board having a plurality of bonding pads arranged in parallel facing the plurality of bonding pads in the optical conversion element.
   Arranged between a plurality of wires arranged in parallel for electrically connecting each of the plurality of bonding pads in the optical conversion element and each of the plurality of bonding pads in the wiring board, and adjacent wires in the plurality of wires. An optical module with a wire assembly having a non-conductive spacer that holds the adjacent wires.
2. Machzenda modulator elements with multiple bonding pads arranged in parallel, including signal bonding pads,
   A driver IC having a plurality of bonding pads arranged in parallel corresponding to a plurality of bonding buds in the Mach Zenda modulator element and amplifying an electric signal input to the Mach Zenda modulator element.
   A wiring board for electrically connecting a plurality of bonding buds in the Machzenda modulator element and a plurality of bonding buds in the driver IC are provided.
   A plurality of wires arranged in parallel for electrically connecting each of the plurality of bonding pads in the driver IC and each of the plurality of bonding pads in the wiring board, and arranged between adjacent wires in the plurality of wires. , An optical module with a group of wires having non-conductive spacers to hold the adjacent wires.
3. The optical module according to claim 1 or 2, wherein the plurality of wires have bonding portions protruding from the end faces of the spacers at both ends thereof.
4. The spacer has a first spacer portion arranged on one end side of the plurality of wires and a second spacer portion arranged on the other end side of the plurality of wires with a gap from the first spacer portion. The optical module according to any one of claims 1 to 3, which has a spacer portion.
5. The light according to any one of claims 1 to 4, wherein the width of the spacer is the same over the entire length, and the distance between adjacent wires located on both side surfaces of the spacer is the same over the entire length. module.
6. The optical module according to any one of claims 1 to 5, wherein the front surface and the back surface of the plurality of wires are exposed.
7. The optical module according to any one of claims 1 to 6, wherein the material of the spacer is a resin adhesive having shape variability after curing.

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