CN115000800B

CN115000800B - Laser chip flip system and method

Info

Publication number: CN115000800B
Application number: CN202210904076.1A
Authority: CN
Inventors: 梁虹; 冯大增; 王奕琼; 武爱民
Original assignee: Shanghai Xihe Technology Co ltd
Current assignee: Shanghai Xihe Technology Co ltd
Priority date: 2022-07-29
Filing date: 2022-07-29
Publication date: 2022-11-08
Anticipated expiration: 2042-07-29
Also published as: CN115000800A

Abstract

The present disclosure relates to chip packaging technologies, and particularly to a laser chip flip system and method. The system provides a substrate chip, a chip driving device, a laser power supply and a photoelectric detector, wherein the chip driving device is used for driving the laser chip to move between a plurality of preset alignment positions of the laser chip and the substrate chip; the laser power supply is used for providing a power supply for generating and outputting laser for the laser chip; the photodetector is used for detecting the relevant light intensity of the silicon-based waveguide. The maximum relevant light intensity in the relevant light intensities corresponding to the multiple alignment positions is determined, and the target alignment position of bonding between the laser chip and the substrate chip is determined based on the maximum relevant light intensity, so that the requirement on the alignment precision of an alignment machine is lowered, and the cost is further lowered; the problems of large optical coupling loss, low optical coupling efficiency and low yield of optoelectronic devices caused by one-time alignment are avoided.

Description

Laser chip flip system and method

Technical Field

The present disclosure relates to chip packaging technologies, and particularly to a laser chip flip system and method.

Background

With the development of electronic products toward multifunction, light weight, small size, and high speed, high density requirements are put forward on chip packaging technology. Conventional lead frame based packages have not been able to accommodate, and many new package formats, such as flip chip packages, have emerged in order to accommodate the demand for further miniaturization of package sizes. The flip chip packaging technology has the advantages of good electrical property and thermal property, high I/O pin density, small packaging size and the like, and is often used in the fields of high-end devices and high-density packaging.

In the flip chip packaging process, the electrode area of the chip is usually faced to the substrate, the interconnection between the chip and the substrate is realized through solder bumps arranged in an array on the chip, and the I/O pins are led out to the periphery.

Under the condition that the chip flip-chip packaging technology is applied to the photoelectron field, a bonding machine is used for pasting a passive laser chip onto a substrate chip in a flip-chip manner, so that the laser chip is directly coupled with an optical waveguide on the substrate chip, the coupling structure is simplified, the size of a photoelectronic device is further reduced, and the production efficiency of the photoelectronic device is improved.

However, flip-chip packaging techniques require extremely high precision in the alignment of the bonder and the bonder is expensive. Meanwhile, the bonding position of the laser chip and the substrate chip determines the matching degree of the shape and the size of a light spot of an active area on the laser chip and the optical waveguide, and further influences the optical coupling efficiency.

Therefore, it is desirable to provide a laser flip chip system and method to reduce the cost of the laser flip chip technology, improve the optical coupling efficiency, and improve the yield of the optoelectronic device.

Disclosure of Invention

The embodiment of the application provides a laser chip flip system and a laser chip flip method, which are used for reducing the cost of a laser chip flip technology, improving the optical coupling efficiency and improving the yield of optoelectronic devices. Specifically, the laser chip flip system is provided with a substrate chip, a chip driving device, a laser power supply and a photoelectric detector, wherein the chip driving device is used for driving the laser chip to move between a plurality of preset alignment positions of the laser chip and the substrate chip; the laser power supply is used for providing a power supply for generating and outputting laser for the laser chip; the photodetector is used for detecting the relevant light intensity of the silicon-based waveguide. The method comprises the following steps: driving a laser chip to move among a plurality of preset alignment positions through a chip driving device; when the silicon substrate is moved to the alignment position, the laser chip is lightened through the laser power supply, and a photoelectric detector is provided for detecting the relevant light intensity of the silicon substrate waveguide; determining the maximum correlated light intensity in the correlated light intensities corresponding to the multiple alignment positions, and determining the target alignment position based on the maximum correlated light intensity; and then bonding between the laser chip and the base chip is performed based on the target alignment position. The multiple alignment mode reduces the requirement on the alignment precision of the alignment machine, thereby reducing the cost; the optimal optical coupling position (namely the target alignment position) is found through multiple times of alignment, so that the problems of large optical coupling loss, low optical coupling efficiency and low yield of optoelectronic devices caused by one-time alignment are solved.

In a first aspect, an embodiment of the present application provides a laser chip flip system, a side surface of a laser chip is provided with an active region for generating and outputting laser, a front surface and a back surface of the laser chip are respectively provided with a laser front electrode and a laser back electrode, and the system includes:

the laser chip comprises a substrate chip, wherein an etching groove for at least containing a part of the laser chip and a silicon-based waveguide for transmitting laser are arranged on the substrate chip; a substrate front electrode of the substrate chip is arranged at the bottom of the etching groove;

the chip driving device is connected to the laser chip and used for driving the laser chip to move among a plurality of preset alignment positions; the multiple alignment positions comprise that an active area of the laser chip is aligned to an incident end face of the silicon-based waveguide within a preset transverse distance from the incident end face of the silicon-based waveguide, and a laser back electrode is aligned to a contact substrate front electrode;

the laser power supply is connected with the laser front electrode and the laser back electrode and is used for providing a power supply for generating and outputting laser for the laser chip;

and the photoelectric detector is connected to the silicon-based waveguide and is used for detecting the related light intensity of the silicon-based waveguide.

In one implementation of the first aspect, a vacuum suction head is provided at a moving end of the chip driving device;

the vacuum suction head is used for sucking the laser chip from the front side of the laser chip.

In one implementation of the first aspect, the two electrodes of the laser power supply are respectively connected with a first probe and a second probe;

the first fixed end of the first probe is connected to the moving end of the chip driving device, the first contact end of the first probe extends towards the laser front electrode of the laser chip, and the first probe is used for being electrically connected with the laser front electrode of the laser chip;

the second probe is used for electrically connecting the laser back electrode of the laser chip.

In one implementation of the first aspect, the second fixed end of the second probe is connected to the moving end of the chip driving device, and the second contact end of the second probe extends toward the substrate front electrode of the substrate chip.

In one implementation of the first aspect, the chip driving device is provided with an L-shaped connector, and the L-shaped connector is used for connecting a second probe;

the L-shaped connecting piece comprises a longitudinal connecting structure and a transverse connecting structure;

the longitudinal fixed end of the longitudinal connecting structure is connected with the movable end of the chip driving device; at the transverse outer side of the laser chip, the longitudinal extending end of the longitudinal connecting structure extends towards the outer side of the back surface of the laser chip;

the transverse fixed end of the transverse connecting structure is connected with the longitudinal extending end of the longitudinal connecting structure; the transverse extending end of the transverse connecting structure extends towards the transverse inner side of the laser chip and is connected with a second fixing end of the second probe; the second contact end of the second probe extends towards the laser back electrode of the laser chip.

In one implementation of the first aspect, the chip driving device is provided with a spacing adjustment structure for adjusting the lateral position and the longitudinal position of the first probe and the second probe.

In one implementation of the first aspect, the silica-based exit end of the silica-based waveguide is connected to a photodetector.

In one implementation of the first aspect, the silica-based waveguide includes a main waveguide and an auxiliary waveguide having the same end face size, and the incident end face of the silica-based waveguide includes a main incident face of the main waveguide and an auxiliary incident face of the auxiliary waveguide; the silicon-based emergent end of the silicon-based waveguide comprises a main emergent end of the main waveguide and an auxiliary emergent end of the auxiliary waveguide;

the auxiliary emergent end of the auxiliary waveguide is connected to the photoelectric detector, and the auxiliary waveguide is used for representing the photoelectric performance of the main waveguide based on a plurality of alignment positions;

the active region of the laser chip is aligned with at least part of the auxiliary entrance face of the auxiliary waveguide with the laser chip in multiple alignment positions.

In the embodiment, the optimal alignment position of the auxiliary incident surface of the auxiliary waveguide and the active region of the laser chip is measured by arranging the auxiliary waveguide with the same cross section size as the main waveguide; and then determining the target alignment position of the main incidence plane and the active region of the laser chip based on the relative position of the auxiliary incidence plane and the main incidence plane, and moving the laser chip to the target alignment position for bonding. The problems that the incident end face of the main waveguide is contacted with the active region of the laser chip for multiple times in the alignment process, and then the incident end face is damaged and optical coupling loss is caused can be solved.

In one implementation of the first aspect, the substrate chip is provided with an optical splitter waveguide, a light splitting incident end of the optical splitter waveguide is connected to the middle portion of the silicon-based waveguide, and a light splitting output end of the optical splitter waveguide is connected to the photodetector.

In one implementation of the first aspect, a cross-sectional side length range of the silicon-based waveguide is determined based on a thickness of a wafer used for manufacturing the substrate chip; the side length range of the cross section comprises one of 0.1-0.5 μm, 0.5-1.5 μm and 1.5-4.5 μm.

In one implementation of the first aspect, a height positioning structure is disposed on the substrate chip; the fixed end of the height positioning structure is arranged at the bottom of the etching groove, the extending end extends upwards, and the height positioning structure is used for limiting the longitudinal distance between the laser chip and the substrate chip.

In an implementation of the first aspect, the incident end face of the silicon-based waveguide is provided with an alignment mark, and the alignment mark is used for identifying the position of the incident end face by the chip driving device.

In a second aspect, an embodiment of the present application provides a laser chip flip method, which is applied to the laser chip flip system, and the method includes:

driving a laser chip to move among a plurality of preset alignment positions through a chip driving device;

when the silicon-based waveguide is moved to each alignment position, a laser power supply is used for providing power for the laser chip, and the related light intensity of the silicon-based waveguide is detected through a photoelectric detector;

determining the maximum relevant light intensity in the relevant light intensities corresponding to the plurality of alignment positions;

determining a target alignment position based on the maximum correlated light intensity;

and bonding between the laser back electrode and the substrate front electrode based on the target alignment position.

In an implementation of the second aspect, the method further includes:

and stopping the laser power supply to supply power to the laser chip when the laser chip leaves the plurality of alignment positions.

In an implementation of the second aspect, the driving the laser chip by the chip driving device to move between a plurality of preset alignment positions includes:

pressing down the laser chip to one of a plurality of alignment positions by the chip driving device;

the laser chip is lifted by the chip driving device and is moved transversely to be above another alignment position in the alignment positions.

The embodiment of the application provides a laser chip flip system and a laser chip flip method, which are used for reducing the cost of a laser chip flip technology, improving the optical coupling efficiency and improving the yield of optoelectronic devices. Specifically, the laser chip flip system is provided with a substrate chip, a chip driving device, a laser power supply and a photoelectric detector, wherein the chip driving device is used for driving the laser chip to move between a plurality of preset alignment positions of the laser chip and the substrate chip; the laser power supply is used for providing a power supply for generating and outputting laser for the laser chip; the photodetector is used for detecting the relevant light intensity of the silicon-based waveguide. The method comprises the following steps: driving a laser chip to move among a plurality of preset alignment positions through a chip driving device; when the silicon substrate is moved to the alignment position, the laser chip is lightened through the laser power supply, and a photoelectric detector is provided for detecting the relevant light intensity of the silicon substrate waveguide; determining a maximum correlated light intensity of the correlated light intensities corresponding to the plurality of alignment positions, and determining a target alignment position based on the maximum correlated light intensity; and then bonding between the laser chip and the base chip is performed based on the target alignment position. The multiple alignment mode reduces the requirement on the alignment precision of the alignment machine, thereby reducing the cost; the optimal optical coupling position (namely the target alignment position) is found through multiple times of alignment, so that the problems of large optical coupling loss, low optical coupling efficiency and low yield of optoelectronic devices caused by one-time alignment are solved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1A is a top view of a portion of a laser chip flip-chip packaging system based on-chip coupling according to an embodiment of the present application;

fig. 1B is a top view of a partial laser chip flip-chip package based on end-to-side coupling according to an embodiment of the present disclosure;

FIG. 2A is a schematic structural diagram of an on-chip coupling-based probe structure according to an embodiment of the present disclosure;

FIG. 2B is a schematic structural diagram of another probe structure based on-chip coupling according to an embodiment of the present disclosure;

FIG. 2C is a schematic structural diagram of a probe structure based on end-to-side coupling according to an embodiment of the present disclosure;

fig. 3 is a schematic diagram of an active region of a laser chip and an incident end surface of a silicon-based waveguide according to an embodiment of the present disclosure;

fig. 4 is a schematic flowchart of a laser chip flip-chip method according to an embodiment of the present disclosure.

The reference numbers in the drawings have the meanings given below:

1-laser chip, Y-active area, 11-laser front electrode, 12-laser back electrode;

2-substrate chip, 21-etching groove, 22-silicon-based waveguide, 221-main waveguide, 222-auxiliary waveguide, S-incidence end face, S1-main incidence face, S2-auxiliary incidence face, B-alignment mark, 23-substrate front electrode, 24-light splitting waveguide, 25-substrate and 26-substrate soldering tin;

3-chip driving device, 31-fixed part, 32-movable part, 33-vacuum suction head and 34-L-shaped connecting piece;

4-laser power supply, 41-power supply, 42-first probe, 43-second probe;

5-photodetector.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic may be included in at least one implementation of the invention. In the description of the present invention, it is to be understood that the terms "upper", "top", "bottom", and the like, as used herein, refer to an orientation or positional relationship based on that shown in the drawings, which is for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be taken as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," and the like are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein.

In order to solve the above technical problem, the present invention discloses a laser chip flip system, which is described in detail below.

Referring to fig. 1A, fig. 2A and fig. 3, fig. 1A is a top view of a portion of a laser chip flip-chip packaging system based on-chip coupling according to an embodiment of the present disclosure; FIG. 2A is a schematic structural diagram of an on-chip coupling-based probe structure according to an embodiment of the present disclosure; fig. 3 is a schematic diagram of an active region of a laser chip and an incident end surface of a silicon-based waveguide according to an embodiment of the present disclosure.

The side surface of the laser chip 1 shown in fig. 1A and 2A is provided with an active region Y (shown in fig. 1A and 3) that generates and outputs laser light, and as shown in fig. 2A, the front surface and the back surface of the laser chip 1 are provided with a laser front surface electrode 11 and a laser back surface electrode 12 shown in fig. 2A, respectively. The Laser chip 1 is provided with a Laser, such as a DFB (Distributed Feedback Laser), an FP (Fabry-Perot Laser), an SOA (Semiconductor Optical Amplifier ), and the like.

Referring to fig. 1A and 2A, the present application provides a laser chip flip-chip system including a substrate chip 2, a chip driving device 3 (shown in fig. 2A), a laser power source 4 (shown in fig. 2A), and a photodetector 5 (shown in fig. 1A). As shown in fig. 1A, the substrate chip 2 is provided with an etched groove 21 for accommodating at least a part of the laser chip 1 and a silicon-based waveguide 22 (i.e., the above-mentioned optical waveguide) for transmitting laser light; as shown in fig. 2A, the substrate front electrode 23 of the substrate chip 2 is disposed at the bottom of the etching groove 21. As shown in fig. 2A, a substrate 25 is disposed at the bottom of the base chip 2, and the material of the substrate 25 may be a silicon core polymer, silicon dioxide, or a composite material. A circuit for connecting the devices is provided on the substrate 25.

The chip driving device 3 includes a fixing portion 31 and a moving portion 32, the moving portion 32 is connected to the laser chip 1, and the fixing portion 31 is disposed on the alignment machine. It is to be understood that the present application does not limit the specific structure of the chip driving device 3.

As shown in fig. 2A, the chip driving device 3 is connected to the laser chip 1, and is configured to move the laser chip 1, so as to flip-chip and paste the laser chip 1 in the etching groove 21 on the substrate chip 2, so that the active region Y of the laser chip 1 is aligned with the incident end surface S of the silicon-based waveguide 22 on the substrate chip 2 (shown in fig. 1A), and the laser back electrode 12 of the laser chip 1 is aligned with the contact substrate front electrode 23. Thus, the laser chip 1 is electrically connected to the substrate chip 2, and the silicon-based waveguide 22 transmits the laser light generated by the laser chip 1 to the outside of the substrate chip 2. In some embodiments of the present application, the chip driving device 3 is disposed on the alignment machine.

As described above, in the prior art, the laser power supply 4 and the photodetector 5 are not included in the flip-chip packaging system of the laser chip 1. The passive laser chip 1 is flip-chip bonded by the chip driver 3 to a unique alignment position in the etched trench 21 on the base chip 2. As mentioned above, this method requires extremely high alignment accuracy for the bonder (i.e., the chip driving device 3), and the cost of the bonder is expensive. Meanwhile, the bonding position of the laser chip 1 and the substrate chip 2 determines the matching degree of the spot shape and the size of the active region Y on the laser chip 1 and the optical waveguide, thereby affecting the optical coupling efficiency. However, the bonding machine aligns the laser chip 1 to the substrate chip 2 and bonds the laser chip at one time, which cannot ensure that the incident end surface S of the silicon-based waveguide 22 has the optimal optical coupling efficiency.

The present application described above provides a laser chip 1 flip-chip system that includes a laser power supply 4 (shown in fig. 2A) and a photodetector 5 (shown in fig. 1A). Specifically, as shown in fig. 2A, the chip driving device 3 is connected to the laser chip 1, and is configured to drive the laser chip 1 to move between a plurality of preset alignment positions. The multiple alignment positions include the active region Y of the laser chip 1 aligned to the entrance facet S of the si-based waveguide 22 within a predetermined lateral distance from the entrance facet S of the si-based waveguide 22, and the laser back electrode 12 aligned to the contact substrate front electrode 23. For example, the predetermined lateral distance is 0.1 μm, so as to save space and ensure sufficient incidence of the laser light to the incident end surface S. As shown in fig. 2A, the laser power supply 4 is connected to the laser front electrode 11 and the laser back electrode 12, and is used for providing a power supply for generating and outputting laser light to the laser chip 1. As shown in fig. 1A, photodetector 5 is coupled to silica-based waveguide 22 for detecting an associated optical intensity of silica-based waveguide 22. For example, the direction of movement between the above-mentioned preset plural alignment positions is laterally moved along the incident end surface S as indicated by an arrow M in fig. 1A to ensure that the laser back electrode 12 can contact the substrate front electrode 23 at each alignment position.

Therefore, the optimal optical coupling position is determined by moving for multiple times based on the preset multiple alignment positions and obtaining the relevant light intensity of the multiple alignment positions through the photoelectric detector 5, the precision requirement on an alignment machine is lowered, the problems that the optical coupling loss is large, the optical coupling efficiency is low and the yield of optoelectronic devices is low due to one-time alignment are avoided.

In some embodiments of the present application, the silicon-based exit end of silicon-based waveguide 22 is connected to photodetector 5, as shown in FIG. 1A. Thus, the photodetector 5 tests the light intensity of the laser transmitted from the silicon-based emitting end. The photodetector 5 may be a detector based on silicon, germanium, or other materials (e.g., a germanium detector), or may be an undoped or low-doped avalanche photodetector.

In some embodiments of the present application, the laser chip 1 flip-chip system further comprises a germanium modulator and a germanium-silicon modulator. The germanium modulator and the germanium-silicon modulator adjust the intensity of light by adjusting the magnitude of the electric field applied to the silicon-based waveguide 22, so that the amplitude, duration, and the like of the light wave change according to a certain rule, thereby achieving the effect of modulating the light signal.

In some embodiments of the present application, the range of the side lengths of the cross-section of the silicon-based waveguide 22 is determined based on the thickness of the wafer used to fabricate the substrate chip 2. Wherein the side length range of the cross section comprises one of 0.1-0.5 μm, 0.5-1.5 μm and 1.5-4.5 μm.

In some embodiments of the present application, the incidence angle of the laser light on the input end surface S of the silicon-based waveguide 22 ranges from 0 to 50. In this incident angle range, the optical coupling efficiency is good.

In some embodiments of the present application, the entrance end surface S of the silicon-based waveguide 22 is provided with an antireflection coating, with a wavelength in the range of 1200nm to 2500nm. To improve the optical coupling efficiency.

When the part of the incident end surface S aligned with the silicon-based waveguide for transmitting laser is electrically contacted with the active region Y, the damage of the incident end surface S and the optical coupling loss are avoided. As shown in fig. 1A, in some embodiments of the present application, the silica-based waveguide 22 includes a main waveguide 221 and an auxiliary waveguide 222 having the same end face size, and the incident end face S of the silica-based waveguide 22 includes a main incident face S1 of the main waveguide 221 and an auxiliary incident face S2 of the auxiliary waveguide 222 (shown in fig. 3); the silica-based exit end of the silica-based waveguide 22 comprises a main exit end of the main waveguide 221 and an auxiliary exit end of the auxiliary waveguide 222; the auxiliary exit end of the auxiliary waveguide 222 shown in fig. 1A is connected to the photodetector 5 (not numbered), and the auxiliary waveguide 222 is used for characterizing the photoelectric performance of the main waveguide 221 based on a plurality of alignment positions; with the laser chip 1 in a plurality of alignment positions, the active region Y of the laser chip 1 is aligned with at least part of the auxiliary entrance face S2 of the auxiliary waveguide 222.

In the present embodiment, by setting the auxiliary waveguide 222 with the same material and cross-sectional size as the main waveguide 221, the optimal alignment position of the auxiliary incident surface S2 of the auxiliary waveguide 222 and the active region Y of the laser chip 1 is measured; and then determining the target alignment position of the main incidence surface S1 and the active area Y of the laser chip 1 based on the relative position of the auxiliary incidence surface S2 and the main incidence surface S1, and moving the laser chip 1 to the target alignment position for bonding. Thus, the problems of damage to the incident end surface S and the active region Y, optical coupling loss, and the like caused by multiple contacts between the incident end surface S of the main waveguide 221 and the active region Y of the laser chip 1 during the alignment process are avoided.

As shown in fig. 1A, in some embodiments of the present application, the substrate chip 2 is provided with an optical splitter waveguide 24, a splitter entrance end of the optical splitter waveguide 24 is connected to the middle portion of the silica-based waveguide 22, and a splitter exit end of the optical splitter waveguide 24 is connected to the photodetector 5. For example, the splitting waveguide 24 splits 5% -20% of the light from the silicon-based waveguide 22 for photodetection. In this way, the photodetector 5 tests the light intensity of the laser light transmitted from the light splitting output end of the light splitting waveguide 24 to determine the light intensity of the silicon-based waveguide 22; and after bonding, the optical intensity of the si-based waveguide 22 is checked without affecting the normal transmission of laser light by the si-based waveguide.

In order to prevent the chip driving device 3 from pressing the substrate chip 2 during the downward movement of the laser chip 1, and thus damage to the laser chip 1 and the substrate chip 2 is prevented. In some embodiments of the present application, the substrate chip 2 is provided with a height positioning structure; the fixed end of the height positioning structure is arranged at the bottom of the etching groove 21, the extending end extends upwards, and the height positioning structure is used for limiting the longitudinal distance between the laser chip 1 and the substrate chip 2. Therefore, the laser back electrode 12 of the laser chip 1 and the front electrode of the substrate chip 2 are determined to be in metal contact through the height positioning structure, further downward movement of the laser chip 1 is limited, and damage to the laser chip 1 and the substrate chip 2 is avoided. For example, the metal contact is realized by a solder bump provided on the laser back electrode 12 side closer to the base front electrode 23 and a substrate solder 26 provided on the base front electrode 23 side closer to the laser back electrode 12 shown in fig. 2A. The material of the substrate solder 26 may include any one of gold-indium alloy, gold-tin alloy, gold-silver alloy, auIn, auSn, and SnAg.

In order to facilitate the chip driving device 3 to move to the alignment position, in some embodiments of the present application, as shown in fig. 3, the incident end surface S of the silicon-based waveguide 22 is provided with an alignment mark B, and the alignment mark is used for the chip driving device 3 to identify the position of the incident end surface S. In this way, by recognizing the position of the alignment marker B, the corresponding alignment position is determined based on the position of the alignment marker B. For example, based on the position of the alignment mark B, the position of the alignment mark B shifted down by 0.5 μm in the longitudinal direction is determined as the alignment position corresponding to the alignment mark B.

As shown in fig. 3, the number of the alignment marks B is plural, and the plural alignment marks correspond to plural alignment positions, respectively. By thus recognizing each alignment mark B, each alignment position is directly recognized. The alignment mark B can be a straight line, a circle, a cross line, an L-shaped mark and the like.

Before the chip driving device 3 moves the laser chip 1, the laser chip 1 needs to be stably clamped and prevented from being damaged, and meanwhile, the laser chip 1 needs to be prevented from being damaged. With continued reference to fig. 2A, in some embodiments of the present application, the moving end of the chip driving device 3 is provided with a vacuum suction head 33, such as the vacuum suction head 33 is provided at the moving portion 32; the vacuum suction head 33 is used to suck the laser chip 1 from the front surface of the laser chip 1. When the vacuum suction head 33 is used, the vacuum suction head 33 can stably clamp the chip by sucking the front surface of the laser chip 1, and the chip is prevented from being damaged. In some embodiments of the present application, the laser chip 1 is gripped by a plurality of vacuum suction heads 33, so that the laser chip 1 is gripped more stably.

The laser chip 1 is small in size, in the process of inversion, the position of the laser chip 1 needs to be moved, and after the target alignment position is determined, the power line needs to be moved away, so that the bonding and packaging operations of other devices are prevented from being influenced. With continued reference to fig. 2A, in some embodiments of the present application, the laser power supply 4 includes a power supply 41, and a first probe 42 and a second probe 43 are connected to two electrodes (i.e., two poles of the power supply 41) of the laser power supply 4, respectively; a first fixed end of the first probe 42 is connected to a moving end of the chip driving device 3, a first contact end of the first probe 42 extends towards the laser front electrode 11 of the laser chip 1, and the first probe 42 is used for electrically connecting the laser front electrode 11 of the laser chip 1; the second probe 43 is used to electrically connect the laser back electrode 12 of the laser chip 1. In this manner, the laser chip 1 is electrically connected using the first probe 42 and the second probe 43, facilitating the power on and off.

Referring to fig. 2B, fig. 2B is a schematic structural diagram of another probe structure based on-chip coupling according to an embodiment of the present disclosure. In some embodiments of the present application, in the case that the laser chip 1 is completely located in the etched groove 21 on the substrate chip 2, the probe structure is as shown in fig. 2B, the second fixed end of the second probe 43 is connected to the moving end of the chip driving device 3, and the second contact end of the second probe 43 extends towards the substrate front electrode 23 of the substrate chip 2. In this manner, due to the metal contact between the laser back electrode 12 and the substrate front electrode 23 at the aligned position, the second contact end of the second probe 43 can be electrically connected to the laser back electrode 12 by adjusting the second contact end of the second probe 43 to extend down to contact the substrate front electrode 23.

Referring to fig. 1B and fig. 2C, fig. 1B is a top view of a portion of a laser chip flip-chip package based on end-to-side coupling according to an embodiment of the present disclosure; fig. 2C is a schematic structural diagram of a probe structure based on end-to-side coupling according to an embodiment of the present application.

As shown in fig. 1B and 2C, in some embodiments of the present application, a part of the laser chip 1 is overlapped on one end of the substrate chip 2, the chip driving device 3 is provided with an L-shaped connector 34, and the L-shaped connector 34 is used for connecting the second probe 43; the L-shaped connector 34 includes a longitudinal connection structure and a transverse connection structure; the longitudinal fixed end of the longitudinal connecting structure is connected to the moving end of the chip driving device 3, for example, the longitudinal fixed end of the longitudinal connecting structure is connected to the moving part 32; at the transverse outer side of the laser chip 1, the longitudinal extending end of the longitudinal connecting structure extends towards the back outer side of the laser chip 1; the transverse fixed end of the transverse connecting structure is connected with the longitudinal extending end of the longitudinal connecting structure; the transversely extending end of the transverse connection structure extends towards the transverse inner side of the laser chip 1 and is connected with the second fixed end of the second probe 43; the second contact end of the second probe 43 extends towards the laser back electrode 12 of the laser chip 1.

With the present embodiment, when the laser chip 1 is partially stacked on the bottom of the etched groove 21, the second contact end of the second probe 43 is adjusted to contact with a portion of the laser back electrode 12 on the back side of the laser chip 1 outside the etched groove 21, so as to directly electrically connect the second contact end of the second probe 43 to the laser back electrode 12.

In some embodiments of the present application, the above-described chip driving device 3 is provided with a pitch adjustment structure for adjusting the lateral position and the longitudinal position of the first probe 42 and the second probe 43. For example, the pitch adjustment structure may enable adjustment of the lateral pitch of the first probe 42 and the second probe 43 within a lateral distance range of 100 μm to 500 μm, and adjustment of the longitudinal pitch of the first probe 42 and the second probe 43 within a longitudinal distance range of 50 μm to 200 μm. For example, the fixed end of the first probe 42 and the fixed end of the second probe 43 are fixed to the moving end of the chip driving apparatus by the pitch adjustment structure.

In this embodiment, for the laser chips 1 with different sizes, the laser front electrode 11, the laser back electrode 12 and the substrate front electrode 23 with different relative positions can be electrically connected to the laser front electrode 11 and the laser back electrode 12 respectively by adjusting the transverse position and the longitudinal position of the first probe 42 and the second probe 43.

The following describes an embodiment of a laser chip 1 flip-chip mounting method according to the present application, and fig. 4 is a schematic flow chart of a laser chip 1 flip-chip mounting method according to the embodiment of the present application, and the present specification provides the method operation steps according to the embodiment or the flow chart, but more or less operation steps may be included based on conventional or non-inventive labor. The order of steps recited in the embodiments is merely one manner of performing the steps in a multitude of orders and does not represent the only order of execution. In actual system or server product execution, sequential execution or parallel execution (e.g., parallel processor or multithreaded processing environments) may occur according to the embodiments or methods shown in the figures. As shown in fig. 4, the method may be applied to the laser chip 1 flip-chip system, and the method includes:

s402: the laser chip 1 is driven by the chip driving device 3 to move between a plurality of preset alignment positions.

In some embodiments of the present application, the driving the laser chip 1 by the chip driving device 3 to move between the predetermined alignment positions includes: pressing down the laser chip 1 to one of a plurality of alignment positions by the chip driving device 3; the laser chip 1 is lifted by the chip driving device 3, and the laser chip 1 is laterally moved above another alignment position among the plurality of alignment positions. So as to prevent the laser chip 1 or the substrate chip 2 from being damaged due to the contact with the substrate chip 2 when the laser chip 1 is moved laterally.

S404: when moved to each alignment position, laser chip 1 is powered by laser power supply 4 and the associated light intensity of silica-based waveguide 22 is detected by photodetector 5. The correlated light intensity is, for example, the light intensity measured at the spectroscopic exit end of the above-described spectroscopic waveguide 24.

S406: a maximum correlated light intensity of the correlated light intensities corresponding to the plurality of alignment positions is determined.

S408: based on the maximum correlated light intensity, a target alignment position is determined. For example, the target alignment position is an alignment position between the main incident surface S1 and the active region Y of the laser chip 1.

S410: based on the target alignment position, bonding is performed between the laser back electrode 12 and the substrate front electrode 23.

In some embodiments of the present application, the laser power supply 4 stops supplying power to the laser chip 1 when the chip driving device 3 moves the laser chip 1 away from the plurality of alignment positions. This saves electrical energy.

In some embodiments of the present application, after the target alignment position is determined, the solder bumps are covered with a conductive adhesive, and then the chip driving device 3 moves the chip to the target alignment position to achieve bonding of the laser chip 1 and the base chip 2.

In some embodiments of the present application, after the bonding of the laser chip 1 and the base chip 2, the photo-coupling paste is filled in the predetermined lateral distance. This may improve the reliability of the encapsulated optoelectronic device, e.g., reduce the effect of humidity on the lifetime of the optoelectronic device.

In summary, the laser chip flip system and the method provided by the embodiment of the present application are used to reduce the cost of the laser chip flip technology, improve the optical coupling efficiency, and improve the yield of the optoelectronic device. Specifically, the system includes the substrate chip 2, the chip driving device 3, the laser power source 4, and the photodetector 5. The chip driving device 3 is used for driving the laser chip 1 to move between a plurality of preset alignment positions of the laser chip 1 and the substrate chip 2; the laser power supply 4 is used for providing a power supply for generating and outputting laser for the laser chip 1; the photodetector 5 is used to detect the relevant light intensity of the silicon-based waveguide. The method comprises the following steps: the laser chip 1 is driven to move among a plurality of preset alignment positions by the chip driving device 3; when the silicon substrate is moved to the alignment position, the laser chip 1 is lightened through the laser power supply 4, and the photoelectric detector 5 is provided for detecting the relevant light intensity of the silicon substrate waveguide; determining the maximum correlated light intensity in the correlated light intensities corresponding to the multiple alignment positions, and determining the target alignment position based on the maximum correlated light intensity; bonding between the laser chip 1 and the base chip 2 is then performed based on the target alignment position. The multiple alignment mode reduces the requirement on the alignment precision of the alignment machine, thereby reducing the cost; the optimal optical coupling position (namely the target alignment position) is found through multiple times of alignment, so that the problems of large optical coupling loss, low optical coupling efficiency and low yield of optoelectronic devices caused by one-time alignment are solved.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

Claims

1. The utility model provides a laser chip flip-chip system, the side of laser chip is provided with the active area that produces and export laser, the front and the back of laser chip set up laser front electrode and laser back electrode respectively, its characterized in that, the system includes:

the laser chip comprises a substrate chip, wherein an etching groove for at least containing a part of laser chip and a silicon-based waveguide for transmitting laser are arranged on the substrate chip; the substrate front electrode of the substrate chip is arranged at the bottom of the etching groove; the silicon-based waveguide comprises a main waveguide and an auxiliary waveguide with the same end face size; the incident end surface of the silicon-based waveguide comprises a main incident surface of the main waveguide and an auxiliary incident surface of the auxiliary waveguide; the silicon-based emergent end of the silicon-based waveguide comprises a main emergent end of the main waveguide and an auxiliary emergent end of the auxiliary waveguide;

the chip driving device is connected to the laser chip and used for driving the laser chip to move among a plurality of preset alignment positions; wherein the plurality of alignment positions comprise the active region of the laser chip aligning the incident facet of the silicon-based waveguide within a predetermined lateral spacing from the incident facet of the silicon-based waveguide, and the laser backside electrode aligning contacting the substrate front side electrode;

the laser power supply is connected with the laser front electrode and the laser back electrode and is used for providing a power supply for generating and outputting the laser for the laser chip; two electrodes of the laser power supply are respectively connected with a first probe and a second probe; the first fixed end of the first probe is connected to the moving end of the chip driving device, the first contact end of the first probe extends towards the laser front electrode of the laser chip, and the first probe is used for being electrically connected with the laser front electrode of the laser chip; the second probe is used for electrically connecting the laser back electrode of the laser chip;

a photodetector for detecting an associated light intensity of the silicon-based waveguide; the photodetector is connected to the auxiliary exit end of the auxiliary waveguide, and the auxiliary waveguide is used for representing the photoelectric performance of the main waveguide based on the plurality of alignment positions; with the laser chip in the plurality of alignment positions, the active region of the laser chip is aligned with at least part of the auxiliary entrance face of the auxiliary waveguide.

2. The system of claim 1, wherein the moving end of the chip driving device is provided with a vacuum suction head;

the vacuum suction head is used for adsorbing the laser chip from the front side of the laser chip.

3. The system of claim 1,

the second fixed end of the second probe is connected to the moving end of the chip driving device, and the second contact end of the second probe extends towards the substrate front electrode of the substrate chip.

4. The system of claim 1, wherein the chip driving device is provided with an L-shaped connector for connecting the second probe;

the longitudinal fixed end of the longitudinal connecting structure is connected to the moving end of the chip driving device; at the transverse outer side of the laser chip, the longitudinal extending end of the longitudinal connecting structure extends towards the back outer side of the laser chip;

the transverse fixed end of the transverse connecting structure is connected with the longitudinal extending end of the longitudinal connecting structure; the transverse extending end of the transverse connecting structure extends towards the transverse inner side of the laser chip and is connected with the second fixing end of the second probe; and the second contact end of the second probe extends towards the laser back electrode of the laser chip.

5. System according to one of claims 1 to 4, characterized in that the chip drive is provided with a pitch adjustment structure,

the spacing adjustment structure is used for adjusting the transverse position and the longitudinal position of the first probe and the second probe.

6. The system according to any one of claims 1 to 4,

and the silicon-based emergent end of the silicon-based waveguide is connected to the photoelectric detector.

7. The system according to any one of claims 1 to 4, wherein the substrate chip is provided with a light splitting waveguide, a light splitting incident end of the light splitting waveguide is connected to an intermediate portion of the silicon-based waveguide, and a light splitting output end of the light splitting waveguide is connected to the photodetector.

8. The system of any one of claims 1 to 4, wherein a cross-sectional side length range of the silicon-based waveguide is determined based on a thickness of a wafer used to fabricate the substrate chip; the side length range of the cross section comprises one of 0.1-0.5 μm, 0.5-1.5 μm and 1.5-4.5 μm.

9. The system according to any one of claims 1 to 4, wherein a height positioning structure is provided on the substrate chip; the fixed end of the height positioning structure is arranged at the bottom of the etching groove, the extending end extends upwards, and the height positioning structure is used for limiting the longitudinal distance between the laser chip and the substrate chip.

10. The system according to any one of claims 1 to 4, wherein the incident end face of the silicon-based waveguide is provided with an alignment mark, and the alignment mark is used for the chip driving device to identify the position of the incident end face.

11. A laser chip flip method applied to the laser chip flip system according to any one of claims 1 to 10, the method comprising:

driving the laser chip to move among the preset alignment positions through the chip driving device;

when the silicon-based waveguide is moved to each alignment position, a laser power supply is used for providing power for the laser chip, and a photoelectric detector is used for detecting the relevant light intensity of the silicon-based waveguide;

determining a maximum correlated light intensity of the correlated light intensities corresponding to the plurality of alignment positions;

bonding between the laser back electrode and the substrate front electrode based on the target alignment position.

12. The method of claim 11, further comprising:

13. The method according to claim 11 or 12, wherein the driving the laser chip between the preset alignment positions by a chip driving device comprises:

pressing down the laser chip to one of the plurality of alignment positions by the chip driving device;

and lifting the laser chip by the chip driving device, and transversely moving the laser chip to be above another alignment position in the alignment positions.