WO2018199602A1

WO2018199602A1 - Optical transmission device with semiconductor laser driving circuit chip integrated therein, and manufacturing method therefor

Info

Publication number: WO2018199602A1
Application number: PCT/KR2018/004755
Authority: WO
Inventors: 박기성; 이길동; 황월연; 양국현
Original assignee: 아이오솔루션(주)
Priority date: 2017-04-27
Filing date: 2018-04-24
Publication date: 2018-11-01
Also published as: KR101917665B1; KR20180120313A; CN110546831A

Abstract

An optical transmission device according to an embodiment of the present invention comprises: a substrate; an optical signal output unit, provided on the substrate, for outputting an optical signal in a first direction; an optical signal output driving circuit chip, provided on the substrate, for supplying a current to the optical signal output unit; a reflection unit, positioned between the optical signal output unit and the optical signal output driving circuit chip, for reflecting light of the optical signal output unit which is outputted in a second direction different from the first direction, in a third direction which is different from the first direction and the second direction; and a photodetector for monitoring which receives the light reflected in the third direction and generates a current corresponding to the reflected light.

Description

Optical transmission device integrated with semiconductor laser driver circuit chip and manufacturing method thereof

The present invention relates to a structure and a manufacturing method of an optical transmission module integrated with a semiconductor laser driving circuit chip.

In the case of the optical transmission module in which the semiconductor laser driver IC is integrated, the optical signal output from the front surface of the semiconductor laser is concentrated and transmitted to the optical fiber, and the light output to the rear of the semiconductor laser enters the monitor photodetector and is proportional to the light intensity. This current is used to stabilize the light output of the semiconductor laser in the driving circuit.

1 shows a general optical transmission device using a semiconductor laser. As shown in FIG. 1, the optical signal output unit 10 outputs an optical signal to the front. The output optical signal is focused by the lens 20 and is incident to the optical fiber 30. The optical signal output driver circuit 40 outputs an optical signal by supplying a current to the optical signal output unit 10, and the intensity of the optical signal is proportional to the magnitude of the current supplied by the optical signal output driver circuit 40.

The optical signal intensity of the optical signal output unit 10 may vary depending on the ambient temperature or the period of use of the optical signal output unit 10, and thus unstable optical signal transmission may occur.

The optical signal output unit 10 also emits light to the rear of the semiconductor laser chip, the intensity of the light emitted to the rear is proportional to the intensity of the optical signal output to the front. The monitoring unit 50 senses the light emitted to the rear of the optical signal output unit 10 using the photodetector and outputs a current corresponding to the sensed light intensity to the power control unit.

The power control unit 60 outputs a control signal to the optical signal output driver circuit 40 according to the current, and the optical signal output driver circuit 40 changes the magnitude of the current according to the control signal. ) Outputs an optical signal of a constant intensity.

Meanwhile, as the optical signal output unit 10 outputs a high speed optical signal, distortion of the optical signal may occur as the arrangement distance between the optical signal output unit 10 and the optical signal output driver circuit 40 increases.

Therefore, recently, in the high speed optical transmission module of 10 Gbps or more, the optical signal output driving circuit 40 and the optical signal output unit 10 of the optical laser output IC chip which can prevent the distortion of the optical signal by integrating the semiconductor laser driver IC chip together inside the optical transmission module Research on packaging is ongoing.

An optical transmission device and a method of manufacturing the same according to an embodiment of the present invention provide an optical packaging structure in which two driving circuit chips and a photodetector chip are located in close proximity to a semiconductor laser operating at a high speed, thereby transmitting a high speed optical signal. This is to reduce distortion of the optical signal.

The problem of the present application is not limited to the above-mentioned problem, another problem that is not mentioned will be clearly understood by those skilled in the art from the following description.

According to one aspect of the invention, the substrate; An optical signal output unit provided on the substrate to output an optical signal in a first direction of the semiconductor laser; An optical signal output driver circuit chip provided on the substrate to supply a current to the optical signal output unit; The optical signal output unit positioned between the optical signal output unit and the optical signal output driver circuit chip and output in a second direction different from the first direction may emit light in the first direction and a third direction different from the second direction. Reflecting portion reflecting to; And a monitoring photodetector configured to receive the light reflected in the third direction and generate a current corresponding to the reflected light.

An interval between the optical signal output unit and the optical signal output driver circuit chip may be 0.2 mm to 0.5 mm.

The reflector may be made of the same material as the substrate and include a reflective body protruding from the substrate and a reflective layer deposited on the reflective body.

The reflective layer may be electrically connected to the ground.

A conductive material made of the same material as the reflective layer may be formed on the substrate.

The reflected light may travel in an empty space between the reflector and the monitoring photodetector.

The optical transmission apparatus according to an aspect of the present invention may further include a monitoring unit substrate provided with the monitoring photodetector, and a support unit spaced apart from the reflecting unit substrate for the monitoring unit.

The optical transmission device according to an aspect of the present invention further includes a monitoring substrate provided with the monitoring photodetector and spaced apart from the reflecting portion, wherein the monitoring photodetector is further compared with the reflecting portion than the monitoring substrate. It may be close.

The monitoring photodetector may be wire bonded with a conductive part filling a via hole formed in the monitoring substrate.

The optical transmission device according to an aspect of the present invention is provided with the monitoring photodetector further comprises a monitoring substrate spaced from the reflecting portion, the reflected light is transmitted through the monitoring substrate for the photodetector for monitoring Can be reached.

The monitoring photodetector and the monitoring substrate may be flip chip bonded.

The light receiving area of the monitoring photodetector for sensing the reflected light may be located opposite to one side of the monitoring photodetector adjacent to the monitoring substrate.

According to another aspect of the invention, by etching the substrate to form a reflective body protruding from the substrate having an inclined surface; Forming a reflective layer capable of reflecting light on the reflective body; Depositing an adhesive material on a first area of the substrate to be provided with an optical signal output unit for outputting an optical signal in a first direction and outputting light in a second direction reflected by the reflective layer of the reflective body; And depositing an adhesive material on a second region of the substrate to be provided with an optical signal output driver circuit chip for supplying current to the optical signal output unit.

According to another aspect of the present invention, a method of manufacturing an optical transmitting apparatus may further include dry etching at least a portion of the remaining regions of the substrate except for the reflective body region to increase the thickness of the reflective body.

The distance between the first region and the second region may be 0.2 mm to 0.5 mm.

According to an exemplary embodiment of the present invention, an optical transmitter and a method of manufacturing the optical transmitter are positioned at an upper end of a semiconductor laser and a driver circuit chip between the optical signal output unit and the optical signal output driver circuit chip. The reflection part reflecting toward the monitoring photodetector allows the driving circuit chip to be positioned close to the rear of the semiconductor laser, thereby reducing distortion of the optical signal during the transmission of the high speed optical signal.

The effects of the present application are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 and 4 show a general semiconductor laser light transmitting apparatus.

2 is a cross-sectional view of an optical transmission device according to an embodiment of the present invention.

3 is a plan view of an optical transmitting apparatus according to an exemplary embodiment of the present invention.

5 and 6 show an optical transmitting apparatus according to another embodiment of the present invention.

7 shows a manufacturing process of a substrate for an optical transmission device according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the accompanying drawings are only described in order to more easily disclose the contents of the present invention, but the scope of the present invention is not limited to the scope of the accompanying drawings that will be readily available to those of ordinary skill in the art. You will know.

Also, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

2 is a cross-sectional view of an optical transmitter according to an embodiment of the present invention, and FIG. 3 is a plan view of a four-channel optical transmitter according to an embodiment of the present invention.

As shown in Figures 2 and 3, the optical transmission device according to an embodiment of the present invention is a substrate 110, an optical signal output unit 130, an optical signal output driver circuit chip 150, a reflector 170 And a photodetector 190 for monitoring.

The substrate 110 may include a silicon optical bench, but is not limited thereto.

The optical signal output unit 130 is provided on the substrate 110 to output the optical signal of the semiconductor laser in the first direction. The optical signal may be output from one side of the optical signal output unit 130. The optical signal in the first direction is incident and focused on a lens (not shown), and the focused optical signal is incident on an optical fiber (not shown) and transmitted.

The optical signal output driver circuit chip 150 is provided on the substrate 110 to supply a current to the optical signal output unit 130. At this time, the optical signal output unit 130 may output the optical signal according to the waveform of the current. A plurality of optical signal output driver circuit chips 150 for implementing a multi-channel and a plurality of optical signal output units 130 corresponding thereto may be implemented on the substrate 110.

For example, as shown in FIG. 3, four optical signal output driver circuit chips 150 for forming four channels on the substrate 110 are provided, respectively, from the optical signal output driver circuit chips 150. Each of the four optical signal output units 130 may output an optical signal by receiving a current of the optical signal output unit 130.

The optical signal output driving circuit chip 150 and the optical signal output unit 130 may be wire-bonded to supply a current.

The reflector 170 is positioned between the optical signal output unit 130 and the optical signal output driver circuit chip 150 to emit light of the optical signal output unit 130 output in a second direction different from the first direction. And reflects in a third direction different from the second direction. The reflector 170 may have an inclined surface inclined by an angle θ to reflect light in the second direction in the third direction.

For example, the optical signal output unit 130 may not only output the optical signal from one side of the optical signal output unit 130 but also emit light from the other side opposite to the one side. In this case, the intensity of light reflected in the third direction may be proportional to the intensity of the optical signal output in the first direction. The reflector 170 monitors the light emitted from the other side of the optical signal output driver circuit chip 150 and the optical signal output unit 130 based on the monitoring photodetector 190 opposite the substrate 110. Can be reflected towards.

The monitoring photodetector 190 receives the light reflected in the third direction and generates a current corresponding to the reflected light. That is, the monitoring photodetector 190 may generate a current having an intensity proportional to the intensity of the reflected light.

The current output from the monitoring photodetector 190 is input to a power controller (not shown), and the power controller transmits a control signal according to the current intensity of the monitoring photodetector 190 to the optical signal output driving circuit chip 150. The optical signal output driving circuit chip 150 outputs an optical signal having a constant intensity by changing the magnitude of the current according to the control signal.

As described above with reference to FIG. 1, in order to transmit a high speed optical signal such as 25 Gbps or more while reducing signal distortion, an optical signal output driver circuit chip 40 and an optical signal output unit implemented on the substrate 70. It should be as close as possible to the distance of (10).

To this end, as shown in FIG. 4A, in the case of a general single channel optical transmission module, an optical signal output driver circuit chip 40 is disposed below the optical signal output unit 10 to provide an optical signal. An arrangement distance between the output unit 10 and the optical signal output driver circuit chip 40 may be reduced. At this time, the placement distance should be about 0.2 mm to 0.5 mm to transmit a high speed optical signal of 10 Gbps to 25 Gbps while reducing signal distortion.

However, as shown in (b) of FIG. 4, in the case of a multi-channel optical transmission module, an optical communication array 80 including a plurality of optical communication output units 10 or a plurality of individual optical communication output units 10. ) May be provided on the substrate 70. Typically, in such a multi-channel optical transmission module, each optical communication output array 80 has a distance of 250 μm to 750 μm between the centers of adjacent optical communication output units 10.

As such, since the distance between the optical communication output units 10 of the optical communication output array 80 is narrow, it is difficult to arrange the optical signal output driver circuit chip 40 at the lower ends of the plurality of optical communication output units 10. In order to solve this problem, the distance between the semiconductor laser optical communication output units 10 of each channel should be increased. In the case of such a multi-channel optical module, the distance between each channel of the semiconductor laser array or the photodetector array for the monitor unit is already standardized. It is difficult for the manufacturer of the transmission device to arbitrarily increase the distance between the optical communication outputs 10.

In addition, since a multi-channel optical fiber array (not shown) having an optical fiber distance of 250 μm to 750 μm is commercially available in accordance with a commercially available optical communication output array 80, the distance between the optical communication output units 10 is arbitrarily determined by the manufacturer of the optical transmitter. Even if you increase the value, it may not make much sense.

Accordingly, as shown in (b) of FIG. 4, the optical signal output driver circuit chip 40 must be disposed behind the optical communication output array 80, and the optical communication output array 80 Since the photodetector 50 for monitoring is disposed at the rear side, the light emitted from the optical signal output unit 10 must be sensed so that the optical communication output array 80 and the optical signal output driver circuit chip 40 are close to each other. Difficult to deploy

Compared with a general optical transmitter, an optical transmitter according to an exemplary embodiment of the present invention has a reflection unit between the optical signal output driver circuit chip 150 and the optical signal output unit 130 as shown in FIGS. 2 and 3. 170, the reflector 170 may reflect the light emitted from the optical signal output unit 130 in the second direction toward the monitoring photodetector 190 in the third direction.

In this case, since the reflector 170 may be implemented on the substrate 110 through a photolithography process, even if the reflector 170 is between the optical signal output unit 130 and the optical signal output driver circuit chip 150, the Gbps may be 25 Gbps. The distance between the optical signal output unit 130 and the optical signal output driver circuit chip 150 may be reduced to transmit the high speed optical signal while reducing distortion. A manufacturing process of the reflector 170 will be described in detail later with reference to the drawings.

In order to be able to transmit a high speed optical signal of 25 Gbps or more while reducing distortion, an interval between the optical signal output unit 130 and the optical signal output driver circuit chip 150 may be 0.2 mm to 0.5 mm, and a reflector ( 170 may be disposed.

As described with reference to FIGS. 2 and 3, the optical signal output driver circuit chip 150 and the optical signal output unit 130 are implemented on a single substrate 110 so that the optical transmission device according to the embodiment of the present invention. May be implemented in the form of a module.

On the other hand, the light reflected through the reflector 170 may travel through the empty space between the reflector 170 and the monitoring photodetector 190 to reach the monitoring photodetector 190. That is, as shown in Figures 2 and 3, the optical transmission device according to an embodiment of the present invention for monitoring from the monitoring substrate 200 and the reflecting unit 170 is provided with a monitoring photodetector 190 The substrate 200 may further include a support 210 spaced apart from the substrate 200. At this time, the substrate for the monitoring unit 200 may be a ceramic substrate, but is not limited thereto.

As such, since the support unit 210 spaces the monitoring substrate 200 and the reflecting unit 170, the support unit 210 may be an empty space between the monitoring substrate 200 and the reflecting unit 170. The light reflected through the unit 170 may reach the monitoring photodetector 190 by traveling through an empty space between the reflector 170 and the monitoring photodetector 190.

Since the reflected light passes through the empty space as described above, the light may proceed without interference, so that the operation of the monitoring photodetector 190 may be stably and accurately performed.

Meanwhile, as described above with reference to FIG. 2, the optical transmission apparatus according to the exemplary embodiment of the present invention further includes a monitoring photodetector 190 and further includes a monitoring substrate 200 spaced apart from the reflector 170. It may include. In this case, the monitoring photodetector 190 may be closer to the reflector 170 than the monitoring substrate 200.

Accordingly, the monitoring photodetector 190 may be wire-bonded with a conductive portion filling the via hole formed in the monitoring substrate 200. Accordingly, one end of the monitoring photodetector 190 and one side of the conductive material of the left via hole may be connected, and the other side of the conductive material of the left via hole may be wire-bonded with the power control unit. In addition, the other end of the monitoring photodetector 190 and one side of the conductive material of the right via hole may be connected, and the other side of the conductive material of the right via hole may be wire-bonded with the power control unit.

On the other hand, as shown in Figure 5, the optical transmission device according to another embodiment of the present invention is provided with a monitoring photodetector 190 and further comprises a monitoring substrate 200 spaced apart from the reflector 170 Can be. In this case, the light reflected by the reflector 170 in the third direction may pass through the monitoring substrate 200 to reach the monitoring photodetector 190. For this purpose, the monitoring substrate 200 may be a light transmissive substrate such as a glass substrate.

Since the reflected light passes through the monitoring substrate 200 to reach the monitoring photodetector 190, the light receiving area of the monitoring photodetector 190 is disposed to be adjacent to or in contact with the monitoring substrate 200. For this purpose, the monitoring photodetector 190 and the monitoring substrate 200 may be flip chip bonding.

Meanwhile, as shown in FIG. 6, the reflected light passes through the monitoring substrate 200 to reach the monitoring photodetector 190, and the light receiving area of the monitoring photodetector 190 senses the reflected light. May be located opposite one side of the monitoring photodetector 190 adjacent to the monitoring substrate 200. For this purpose, the monitoring photodetector 190 may include a backside illumination motoring photodiode.

For reference, FIGS. 5 and 6 do not show the support 210 for convenience of description.

Next, a method of manufacturing an optical transmitting apparatus according to an embodiment of the present invention will be described with reference to the drawings.

7 shows a manufacturing process of a silicon substrate of the optical transmission device according to an embodiment of the present invention. As shown in FIG. 7A, the substrate 110 is etched according to a mask pattern to protrude from the substrate 110 to form a reflective body 171 having an inclined surface. In this case, the etching may be V groove etching by chemical wet etching. In addition, the substrate 110 may be a silicon wafer, but is not limited thereto.

The angle of the inclined surface may vary depending on the crystal structure of the substrate 110 or the direction in which the ingot is sliced. For example, the angle of the inclined surface may be 45 degrees or 54.7 degrees, but is not limited thereto.

In the substrate manufacturing method of the optical transmission device according to an embodiment of the present invention, as shown in Figure 7 (b), dry etching at least a portion of the remaining region of the substrate 110, except for the reflective body 171 region. The method may further include increasing the thickness of the reflective body 171. In this case, etching may be performed in a vertical direction with respect to the substrate 110 through dry etching.

As described above, the thickness of the reflective body 171 is increased because the thickness of the semiconductor laser for the optical signal output unit 130 needs to be considered. Unlike the embodiment of the present invention, if the thickness of the reflecting body 171 does not increase, the height of the reflector 170 is lowered to sufficiently reflect the light emitted in the second direction of the semiconductor laser for the optical signal output unit 130. You may not be able to.

Meanwhile, as shown in FIG. 7C, a reflective layer 173 capable of reflecting light is formed on the reflective body 171. The reflective layer 173 may be made of a conductive material, and the conductive material may be a stacked structure of Au and Ti, but is not limited thereto.

As such, the reflector 170 may include a reflective body and a reflective layer 173. In this case, since the reflective body 171 is made by etching the substrate 110, the reflective body 171 may be made of the same material as the substrate 110 and protrude from the substrate 110. The reflective layer 173 may be formed by depositing on the reflective body 171.

Since the reflective layer 173 is made of a conductive material, the reflective layer 173 may be electrically connected to the ground. Therefore, as shown in FIG. 7C, the reflective layer 173 may be deposited on at least a portion of the substrate 110 as well as the reflective body 171. That is, a conductive material made of the same material as the reflective layer 173 may be formed on the substrate 110.

As shown in FIGS. 7D and 7E, an optical signal outputs an optical signal in a first direction and outputs light in a second direction reflected by the reflective layer 173 formed on the reflective body 171. The adhesive material 230 is deposited on the first region of the substrate 110 on which the output unit 130 is to be provided.

In addition, as illustrated in FIGS. 7D and 7E, the second region of the substrate 110 to be provided with the optical signal output driver circuit chip 150 for supplying current to the optical signal output unit 130. An adhesive material 230 is deposited on it.

In this case, setting of the first region and the second region may be performed by SiO ₂ passivation deposition, and the adhesive material 230 may be a solder of Au / Sn alloy, but is not limited thereto.

In addition, the setting of the first region and the second region may be simultaneously performed, and the deposition of the adhesive material 230 on the first region and the second region may also be simultaneously performed.

As such, since the reflector 170 is formed between the first region and the second region through a lithography process, the optical signal output unit 130 and the optical signal output driving circuit chip are capable of reducing or eliminating distortion of the high speed optical signal. The distance between the first area and the second area may be 0.2 mm to 0.5 mm so that 150 is disposed closely.

As described above, the embodiments of the present invention have been described, and the fact that the present invention can be embodied in other specific forms without departing from the spirit or scope of the present invention can be embodied by those skilled in the art. It is self-evident to. Therefore, the above-described embodiments should be regarded as illustrative rather than restrictive, and thus, the present invention is not limited to the above description and may be modified within the scope of the appended claims and their equivalents.

Claims

Board;

An optical signal output unit provided on the substrate and outputting an optical signal of a semiconductor laser in a first direction;

An optical signal output driver circuit chip provided on the substrate to supply a current to the optical signal output unit;

The optical signal output unit positioned between the optical signal output unit and the optical signal output driver circuit chip and output in a second direction different from the first direction may emit light in the first direction and a third direction different from the second direction. Reflecting portion reflecting to; And

And a photodetector for monitoring that receives the light reflected in the third direction and generates a current corresponding to the reflected light.
The method of claim 1,

And the optical signal output unit and the optical signal output driver circuit chip have a distance of 0.2 mm to 0.5 mm.
The method of claim 1,

The reflector is made of the same material as the substrate and the optical transmission device, characterized in that it comprises a reflective body protruding from the substrate and a reflective layer deposited on the reflective body.
The method of claim 3,

And the reflective layer is electrically connected to the ground.
The method of claim 4, wherein

And a conductive material formed of the same material as the reflective layer on the substrate.
The method of claim 1,

And the reflected light travels through an empty space between the reflecting unit and the monitoring photodetector.
The method according to claim 1 or 6,

A monitoring substrate provided with the monitoring photodetector;

And a support part for separating the monitoring substrate from the reflecting part.
The method of claim 1,

The monitoring photodetector is provided and further comprises a monitoring substrate spaced from the reflecting portion,

And said monitoring photodetector is closer to said reflecting portion than said monitoring substrate.
The method of claim 8,

The monitoring photodetector,

And a wire bonding portion with a conductive portion filling the via hole formed in the monitoring substrate.
The method of claim 1,

The monitoring photodetector is provided and further comprises a monitoring substrate spaced from the reflecting portion,

And the reflected light passes through the monitoring substrate to reach the monitoring photodetector.
The method of claim 10,

And the monitoring photodetector and the monitoring substrate are flip chip bonded.
The method of claim 10,

And a light receiving area of the monitoring photodetector for sensing the reflected light is located opposite one side of the monitoring photodetector chip adjacent to the monitoring substrate.
Etching the substrate to form a reflecting body protruding from the substrate and having an inclined surface;

Forming a reflective layer capable of reflecting light on the reflective body;

Depositing an adhesive material on a first region of the substrate to be provided with an optical signal output unit for outputting an optical signal of a semiconductor laser in a first direction and outputting light in a second direction reflected by a reflective layer of the reflective body;

Depositing an adhesive material on a second region of the substrate to be provided with an optical signal output driver circuit chip supplying current to the optical signal output unit;

Method of manufacturing an optical transmission device comprising a.
The method of claim 13,

And dry-etching at least a portion of the remaining areas of the substrate other than the reflective body area to increase the thickness of the reflective body.
The method of claim 13,

The distance between the first region and the second region is a manufacturing method of the optical transmission device, characterized in that 0.2 mm to 0.5 mm.