KR102312392B1 - Method of attaching substrates for a lidar module - Google Patents

Abstract

In the bonding method of a substrate for a lidar module, a device substrate in which laser light emitting devices are bonded to each of electrode pads is positioned on a stage module. The optical array substrate having the optical array is vacuum-adsorbed by the bonding module so as to face the element substrate positioned on the stage module. Then, the optical array substrate and the element substrate are brought into a primary approach, and in a state where the optical array substrate and the element substrate are primarily approached, first center data regarding element center coordinates for each of the light emitting elements and the optical arrays and the array center Secure second central data regarding the coordinates. Thereafter, the optical array substrate and the element substrate are aligned with each other using the first and second central data, and the optical array substrate and the element substrate are secondarily approached to attach the optical array substrate and the element substrate to each other by a bonding module. Thereby, the device substrate and the optical array substrate can be bonded more precisely.

Description

Bonding method of substrate for lidar module

Embodiments of the present invention relate to a bonding method of a substrate for a lidar module. More specifically, embodiments of the present invention relate to a method of bonding a substrate for a lidar module for mutually bonding a device substrate and an optical array substrate included in the lidar module.

In general, since the surface light laser emits light in the stacking direction of the semiconductor material layer, it is easy to combine with other optical devices and install, and it can be manufactured to have a two-dimensional arrangement, so that the interface using optical communication and optical signals It can be widely applied as a light source in optical transmission systems such as technology or optical heads for recording/reproduction.

In the active use of the surface light laser, recently, interest in a VCSEL (Vertical Cavity Surface Emitting Laser) is increasing. Vixel is a semiconductor laser that emits a laser in a direction perpendicular to the upper surface, and has the advantage of being able to produce a miniaturized product due to its simple manufacturing process and easy mass production.

On the other hand, Big Cell has been mainly applied to the communication field, but recently, attempts to apply it to the optical system are actively in progress. In particular, with the spotlight of autonomous vehicles, attempts to apply Bixel to LiDAR modules are actively being made.

The lidar module includes a device substrate and an optical array substrate. When the device substrate and the optical array substrate are more precisely aligned, better characteristics may be obtained.

Embodiments of the present invention provide a bonding method of a substrate for a lidar module capable of bonding by precisely aligning a device substrate including a light emitting device and an optical array substrate including an optical array with each other.

In the bonding method of a substrate for a lidar module according to embodiments of the present invention, a device substrate in which laser light emitting devices are bonded to each of the electrode pads is positioned on the stage module. The optical array substrate having the optical array is vacuum-adsorbed by the bonding module to face the element substrate positioned on the stage module. Next, the optical array substrate and the element substrate are brought into a primary approach, and in a state in which the optical array substrate and the element substrate are primarily approached, a second reference to element center coordinates for each of the light emitting elements and the optical arrays 1 Secure the center data and the second center data regarding the array center coordinates. Thereafter, the optical array substrate and the element substrate are aligned with each other using the first and second central data, and the optical array substrate and the element substrate are made secondary to approach, so that the optical array substrate and the element substrate are connected to the bonding module. The device substrates are attached to each other.

In one embodiment of the present invention, in order to secure the first central data, a pole image is obtained by imaging active poles formed in each of the light emitting devices using a camera mounted on the bonding module, and , it is possible to secure center coordinates of each of the active poles by using the pole image.

Here, it is possible to check whether the device substrate and the optical array substrate are aligned by overlapping the pole image and the images related to the optical array.

In one embodiment of the present invention, in order to secure the second central data, an array image for each of the optical arrays is obtained using a camera mounted on the bonding module, and the optical array image is used to obtain the optical array image. It is possible to secure the center coordinates of each of the arrays.

Here, ring illumination may be used to obtain an array image for each of the optical arrays using a camera mounted on the bonding module.

In an embodiment of the present invention, before attaching the optical array substrate and the element substrate to each other, a spacer may be positioned on the outer periphery of the optical array substrate, and a photocurable adhesive may be applied to the upper surface of the spacer.

Here, in order to attach the optical array substrate and the device substrate to each other, UV light may be irradiated toward the photocurable adhesive.

According to the manufacturing method of the substrate for the lidar module according to the embodiments of the present invention as described above, the optical array substrate and the element substrate are primarily approached, and in a state in which the optical array substrate and the element substrate are primarily approached , secure first center data regarding element center coordinates for each of the light emitting elements and the optical arrays and second center data regarding array center coordinates. Thereafter, the optical array substrate and the element substrate are aligned with each other using the first and second central data, and the optical array substrate and the element substrate are made secondary to approach, so that the optical array substrate and the element substrate are connected to the bonding module. The device substrates are attached to each other. Accordingly, the device substrate and the optical array substrate may be more precisely aligned while maintaining a constant distance.

1 is a flowchart for explaining a method of bonding a substrate for a lidar module according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating a substrate bonding apparatus for implementing the bonding method illustrated in FIG. 1 .
FIG. 3 is a cross-sectional view illustrating a stage module and a bonding module illustrated in FIG. 2 .
FIG. 4 is images obtained by capturing the device substrate shown in FIG. 2 .
FIG. 5 is images obtained by capturing the optical array substrate shown in FIG. 2 .
6 is a cross-sectional view for explaining an example of a lidar module manufactured according to embodiments of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention should not be construed as being limited to the embodiments described below and may be embodied in various other forms. The following examples are provided to fully convey the scope of the present invention to those skilled in the art, rather than to enable the present invention to be fully completed.

In embodiments of the present invention, when an element is described as being disposed or connected to another element, the element may be directly disposed or connected to the other element, and other elements may be interposed therebetween. it might be Alternatively, when one element is described as being directly disposed on or connected to another element, there cannot be another element between them. Although the terms first, second, third, etc. may be used to describe various items such as various elements, compositions, regions, layers and/or portions, the items are not limited by these terms. will not

The terminology used in the embodiments of the present invention is only used for the purpose of describing specific embodiments, and is not intended to limit the present invention. In addition, unless otherwise limited, all terms including technical and scientific terms have the same meaning as understood by one of ordinary skill in the art of the present invention. The above terms, such as those defined in ordinary dictionaries, shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art and description of the present invention, and unless explicitly defined, ideally or excessively outwardly intuitively. will not be interpreted.

Embodiments of the present invention are described with reference to schematic diagrams of ideal embodiments of the present invention. Accordingly, variations from the shapes of the diagrams, eg, variations in manufacturing methods and/or tolerances, are those that can be fully expected. Accordingly, embodiments of the present invention are not to be described as being limited to the specific shapes of the areas described as diagrams, but rather to include deviations in the shapes, and the elements described in the drawings are entirely schematic and their shapes It is not intended to describe the precise shape of the elements, nor is it intended to limit the scope of the present invention.

1 is a flowchart for explaining a method of bonding a substrate for a lidar module according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a substrate bonding apparatus for implementing the bonding method illustrated in FIG. 1 . FIG. 3 is a cross-sectional view illustrating a stage module and a bonding module illustrated in FIG. 2 .

1 to 3 , a substrate bonding apparatus is provided to implement a bonding method of a substrate for a lidar module according to an embodiment of the present invention.

2 and 3 , the substrate bonding apparatus includes a stage module 100 , a bonding module 200 , and a vision module. The substrate bonding apparatus may mutually bond the element substrate to which the light emitting element is bonded and the array substrate on which the optical array is formed.

The stage module 100 supports the device substrate 10 . The stage module 100 includes a first lifting unit 110 , a stage 130 capable of vacuum adsorbing the device substrate 10 , a horizontal driving unit 150 , and a rotation driving unit 170 .

The first lifting unit 110 may include, for example, a ball screw, an LM guide, and the like. In the first lifting unit 110 , a first vacuum line 111 , a first vacuum chamber 113 communicating with the first vacuum line 111 , and a first branched from the first vacuum chamber 113 . It includes a vacuum hole 115 .

The horizontal driving unit 150 and the rotation driving unit 170 may rotate the stage 130 in a horizontal direction and a rotation direction crossing each other.

The bonding module 200 is disposed on the stage module 110 . The bonding module 200 adsorbs the optical array substrate 20 . In addition, the bonding module 200 may elevate the optical array substrate 20 and bond to the device substrate 10 .

The bonding module 200 includes a second lifting unit 210 , a bonding head 230 , and a vertical driving unit 250 .

The second lifting unit 210 elevates the bonding head 230 in a vertical direction. The second lifting unit 210 may include, for example, a ball screw, an LM guide, and the like.

A second vacuum line 211 in the second lifting unit 210, a second vacuum chamber 213 communicating with the second vacuum line 211, and a second branching from the second vacuum chamber 213 It includes a vacuum hole 215 . Accordingly, the bonding head 230 may adsorb the optical array substrate using vacuum force.

The vision module 300 may image the optical array 21 (refer to FIG. 6 ) and the light emitting device 13 (refer to FIG. 6 ). The vision module 300 may be mounted on the bonding module 200 . Alternatively, the vision module 300 may be provided independently from the bonding module 200 . The vision module 300 includes a camera (not shown) and a light source 35 (refer to FIG. 5 ).

Hereinafter, a method of bonding a substrate for a lidar module will be described in detail.

First, the device substrate 10 is positioned on the spag module (S110). The stage module 100 may use a vacuum force to fix the device substrate 10 . Accordingly, the stage module 100 can be firmly fixed without impact to the device substrate 10 having a relatively thin thickness.

At this time, the light emitting device 13 (refer to FIG. 6 ) is bonded to the device substrate 10 . The light emitting device may generate laser light. A detailed description of the light emitting device will be omitted.

Meanwhile, the optical array substrate 20 is adsorbed to face the device substrate 10 ( S120 ). In this case, the bonding module 200 may firmly fix the optical array substrate 20 having a relatively thin thickness by adsorbing the optical array substrate 20 with a vacuum force.

The optical array substrate 20 may include an optical array arranged in a matrix form, for example, lenses 21 . Alternatively, a prism or the like may be formed on the optical array substrate 20 .

Next, the optical array substrate 20 and the device substrate 10 are brought into a primary approach (S140). At this time, the optical array substrate 20 and the device substrate 10 are moved to an alignment position.

Therefore, before bonding the optical array substrate 20 and the element substrate 10 to each other in the bonding position, the state in which the optical array substrate 20 and the element substrate 10 are vertically adjacent in the alignment position can keep Accordingly, an alignment error that may occur as the optical array substrate 20 and the device substrate 10 move from the alignment position to the bonding position may be reduced.

Furthermore, the camera included in the vision module 00 may directly position the elements formed on the device substrate 10 as well as the optical array formed on the optical array substrate 20 within an imaging range. In this case, since the camera has an auto-focusing function, both the light emitting device and the optical array may be imaged.

Next, the light emitting devices are imaged using the vision module 300 to secure first center data for the center coordinates of each of the light emitting devices ( S150 ). Meanwhile, the optical arrays are imaged using the vision module to secure second center data for the center coordinates of each of the optical arrays.

FIG. 4 is images obtained by capturing the device substrate shown in FIG. 2 .

Referring to FIG. 4 , in order to secure first center data for the center coordinates of each of the light emitting devices, position coordinates of an active pole formed in the light emitting devices are secured. When each of the active poles has a circular shape, the position coordinates of the active poles may correspond to center coordinates of the center of the active poles.

FIG. 5 is images obtained by capturing the optical array substrate shown in FIG. 2 .

Referring to FIG. 5 , in order to secure second center data for center coordinates of each of the optical arrays, position coordinates for the optical array provided in the optical array substrate 20 are secured. When the optical array has a convex lens shape, a center coordinate for the optical array may correspond to a second center coordinate with respect to a center of each of the convex lenses. Thereby, the second center data regarding the array center coordinates is secured.

In an embodiment of the present invention, the vision module 300 may include a ring light 35 . When the ring light 35 includes an LED light source, a plurality of light sources may be imaged on each of the convex lenses with respect to the optical array. Accordingly, position coordinates for each of the convex lenses may be obtained by using the light source images formed on each of the convex lenses.

Referring back to FIGS. 1 to 3 , the optical array substrate and the device substrate are aligned using the first and second central data ( S170 ).

To this end, a first driving unit capable of driving four or more axes mounted on the stage module 100 may be included. That is, the first driving unit moves the device substrate positioned in the stage module 100 by rotating and rotating in horizontal and vertical directions that intersect with each other. Accordingly, the device substrate and the optical array substrate may be aligned with each other.

Alternatively, a second driving unit capable of driving three or more axes mounted on the bonding module 200 may be included.

Next, the optical array substrate 20 and the element substrate 10 are brought into a secondary approach, and the optical array substrate 20 and the element substrate 10 are mutually attached to each other with the bonding module 200 (S190). ).

That is, the optical array substrate 20 and the device substrate 10 move from the alignment position to the bonding position. As a result, a movement distance of the optical array substrate 20 and the device substrate 10 from the alignment position to the bonding position is reduced, thereby reducing alignment errors that may occur during movement.

In one embodiment of the present invention, before the step of attaching the optical array substrate 20 and the device substrate 10 to each other, a spacer (not shown) is positioned on the outer periphery of the optical array substrate 20 . The spacer may maintain a gap between the optical array substrate 20 and the device substrate 10 . In this case, the height of the spacer may be adjusted according to the focal length of the optical array 21 formed on the optical array substrate 20 , for example, a lens.

Thereafter, a photocurable adhesive (not shown) may be applied to the upper surface of the spacer. Then, UV light is irradiated toward the photocurable adhesive to cure the photocurable adhesive, thereby bonding the optical array substrate 20 and the device substrate 10 to each other. To this end, the bonding head 200 may further include a UV light source (not shown).

6 is a cross-sectional view for explaining an example of a lidar module manufactured according to embodiments of the present invention.

Referring to FIG. 6 , an electrode pad 11 is provided on a device substrate 10 , and a laser light emitting device 13 is bonded to the electrode pad. The device substrate 10 to which the laser light emitting device 13 is bonded may transmit an electrical signal to the laser light emitting device through the electrode pad. Accordingly, the laser light emitting device 13 may output a light emitting beam toward the optical array substrate 20 .

The device substrate 10 may be made of a ceramic material having relatively high insulation and thermal conductivity. Electronic components necessary for laser emission may be additionally provided on the device substrate 10 . For example, the device substrate 10 may be formed of a PCB substrate and a semiconductor laminated in multiple layers.

The laser light emitting device 13 may specifically include a VCSEL chip (Vertical Cavity Surface Emitting Laser Chip). The laser light emitting device 13 emits light perpendicular to the direction in which the laser light emitting device 13 is arranged.

In addition, a plurality of the laser light emitting devices 13 may be provided and may be bonded to the device substrate 10 using eutectic bonding. Specifically, a film adhesive 12 formed in a film form may be interposed between the electrode pad 11 and the laser light emitting device 13 . In this state, the laser light emitting device 13 may be bonded to the electrode pad 11 by heating the film adhesive 12 to a molten state. The film adhesive 15 may include a metal mixture and alloy composed of gold, silver, tin, lead, and the like.

The optical array substrate 20 is disposed on the device substrate 10 . Accordingly, the optical array substrate 20 may receive the emission beam output from the device substrate 10 and refract and diffract the emission beam.

Although the above has been described with reference to the preferred embodiment of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention as set forth in the following claims. You will understand that there is

Claims (7)

placing, on the stage module, a device substrate to which laser light emitting devices are bonded to each of the electrode pads;
vacuum adsorbing an optical array substrate having an optical array to a bonding module to face the element substrate positioned on the stage module;
first approaching the optical array substrate and the device substrate;
In a state where the optical array substrate and the element substrate are primarily approached, using a camera mounted on the bonding module and having an auto-focusing function and capable of directly positioning the optical array and the light emitting elements within an imaging range, the optical obtaining first center data regarding element center coordinates for each of the light emitting elements and the optical array and second center data regarding array center coordinates by imaging the array and the laser light emitting devices;
aligning the optical array substrate and the device substrate using the first and second center data; and
The bonding method of a substrate for a lidar module comprising the step of attaching the optical array substrate and the element substrate to each other with the bonding module by making the optical array substrate and the element substrate secondary to each other. The method of claim 1, wherein the securing of the first central data comprises:
acquiring a pole image by imaging active poles formed on each of the light emitting devices using a camera mounted on the bonding module; and
and securing the center coordinates of each of the active poles by using the pole image. The bonding of the substrate for a lidar module according to claim 2, further comprising the step of checking whether the device substrate and the optical array substrate are aligned by superimposing the pole image and the images related to the optical array to each other. Way. The method of claim 1, wherein the securing of the second central data comprises:
acquiring an array image for each of the optical arrays using a camera mounted on the bonding module; and
The bonding method of the substrate for a lidar module, characterized in that it comprises the step of securing the center coordinates of each of the optical arrays using the array image. [Claim 5] The method of claim 4, wherein the step of acquiring an array image for each of the optical arrays using a camera mounted on the bonding module uses ring illumination. The method of claim 1 , wherein before the step of attaching the optical array substrate and the device substrate to each other,
locating a spacer on an outer periphery of the optical array substrate; and
The bonding method of a substrate for a lidar module, characterized in that it further comprises the step of applying a photocurable adhesive to the upper surface of the spacer. The bonding method of claim 6, wherein the step of attaching the optical array substrate and the device substrate to each other comprises irradiating UV light toward the photocurable adhesive.

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