WO2022264329A1

WO2022264329A1 - Optical connection structure and method for manufacturing same

Info

Publication number: WO2022264329A1
Application number: PCT/JP2021/022912
Authority: WO
Inventors: 昇男佐藤; 光太鹿間; 洋平齊藤
Original assignee: 日本電信電話株式会社
Priority date: 2021-06-16
Filing date: 2021-06-16
Publication date: 2022-12-22
Also published as: JPWO2022264329A1

Abstract

This optical connection structure (10) comprises: a first optical element (11) disposed on a first substrate (111) and having a first waveguide (113); a second optical element (12) having a second waveguide (123); a self-formed waveguide (131) connecting one end of the first waveguide (113) and one end of the second waveguide (123); and a first received light guiding part (114) disposed at the other end of the first optical waveguide (113).　Consequently, the present invention can provide a low-loss optical connection structure using a self-formed waveguide.

Description

Optical connection structure and its manufacturing method

The present invention relates to an optical connection structure using a self-forming waveguide and a manufacturing method thereof.

Planar Lightwave Circuit (PLC) equipped with optical waveguides, Silicon Photonics (SiPh), Indium Phosphorus (InP) compound semiconductor chips, etc. are used to connect different types of substrates to advance functionality. Efforts have been made (Non-Patent Document 1).

In addition, research is also underway on fan-out packaging by joining optical element chips made on another substrate to the other substrate as a study of low-cost batch manufacturing technology at the wafer level, similar to electric circuits (non-patented). Reference 2). In Non-Patent Document 2, the light from the optical element chip is emitted into space.

Using these techniques, for example, as shown in FIG. 14A, after periodically forming PLC chips 51 having glass waveguides 513 on a wafer 5_1, concave portions 515 are formed to expose the silicon of the substrate.

On the other hand, a laser diode (LD) (not shown) is formed on another indium phosphide substrate and diced into chips. The LD chip 52 is mounted and fixed so that the optical waveguide 523 for propagating light from the LD of the LD chip 52 is connected to the glass waveguide 513 of the PLC chip 51 (FIG. 14B).

At this time, for example, image recognition can be used for alignment, and intermolecular force can be used for fixation, and there is a bonding device dedicated to this process. As a result, chips made of different materials can be integrated and mounted on a wafer for collective manufacturing.

However, since visible light is used for image recognition, it was difficult to position and mount with sufficiently high positional accuracy compared to visible light wavelengths.

In addition, it was difficult to ensure the positional reproducibility of mechanical chip handling tools, and the positional accuracy was limited to about ±3 microns. This accuracy does not pose a problem when emitting light into space or when securing electrical connection, but it is insufficient when connecting waveguides.

For example, in a PLC using a glass material, the width of the optical waveguide is about 10 microns, so if the positions of the optical waveguides to be connected are shifted by 3 microns, the optical connection loss increases.

Furthermore, when the refractive index of a waveguide material such as a SiN waveguide, an InP waveguide, or a SiPh waveguide is high, the width of the optical waveguide becomes narrow, so there is a problem that the optical connection cannot be made with an accuracy of ±3 microns due to the large loss. rice field.

In order to solve the above-described problems, an optical connection structure according to the present invention is arranged on a first substrate and includes a first optical element having a first optical waveguide and a second optical element having a second optical waveguide. 2 optical elements, a self-forming waveguide connecting one end of the first optical waveguide and one end of the second optical waveguide, and a first receiver disposed at the other end of the first optical waveguide. and a light guide.

In addition, a method for manufacturing an optical connection structure according to the present invention includes: a first optical element having a first optical waveguide and a first light receiving light guide portion disposed at the other end of the first optical waveguide; A method for manufacturing an optical connection structure for optically connecting a second optical element having a second optical waveguide and a second light receiving light guide portion arranged at the other end of the second optical waveguide, the method comprising: a step of collectively forming a plurality of said first optical elements on one substrate; collectively forming a plurality of said second optical elements on a second substrate to form said second optical elements as a chip; fixing the first optical element and the second optical element by bringing the end face of the first optical waveguide and the end face of the second optical waveguide close to each other; a step of filling a photocurable resin between the end face of the first optical waveguide and the end face of the second optical waveguide; forming a self-formed waveguide by exposing to light so as to be incident on the portion and the second light-receiving light guide portion, and irradiating the photo-curing resin with the resin-curing light to form a self-formed waveguide; forming a cladding having a refractive index lower than that of the self-forming waveguide.

According to the present invention, a low-loss optical connection structure using a self-forming waveguide and a manufacturing method thereof can be provided.

FIG. 1A is a schematic top view showing the configuration of the optical connection structure according to the first embodiment of the invention. 1B is a schematic side view showing the configuration of the optical connection structure according to the first embodiment of the present invention; FIG. FIG. 1C is a schematic top view showing the configuration of the second optical element in the optical connection structure according to the first embodiment of the present invention; FIG. 2A is a schematic top view for explaining an example of the method for manufacturing the optical connection structure according to the first embodiment of the invention. FIG. 2B is a schematic side view for explaining an example of the method for manufacturing the optical connection structure according to the first embodiment of the present invention; FIG. 2C is a schematic side view for explaining an example of the method for manufacturing the optical connection structure according to the first embodiment of the present invention; FIG. 2D is a schematic side view for explaining an example of the method for manufacturing the optical connection structure according to the first embodiment of the present invention; FIG. 2E is a schematic side view for explaining an example of the method for manufacturing the optical connection structure according to the first embodiment of the present invention; FIG. 2F is a schematic side view for explaining an example of the method for manufacturing the optical connection structure according to the first embodiment of the present invention; FIG. 2G is a schematic side view for explaining an example of the method for manufacturing the optical connection structure according to the first embodiment of the present invention; FIG. 2H is a schematic side view for explaining an example of the method for manufacturing the optical connection structure according to the first embodiment of the present invention; FIG. 3 is a schematic side view for explaining an example of the method for manufacturing the optical connection structure according to the first embodiment of the invention. FIG. 4A is a schematic top view for explaining the effects of the optical connection structure and its manufacturing method according to the first embodiment of the present invention. FIG. 4B is a schematic top view for explaining the effects of the optical connection structure and its manufacturing method according to the first embodiment of the present invention. FIG. 5A is a schematic top view showing an example of the configuration of a light-receiving light guide section in the optical connection structure according to the first embodiment of the present invention; FIG. 5B is a schematic side view showing an example of the configuration of the light-receiving light guide section in the optical connection structure according to the first embodiment of the present invention; FIG. 6A is a schematic top view showing an example of the configuration of a light-receiving light guide section in the optical connection structure according to the first embodiment of the present invention; FIG. 6B is a schematic side view showing an example of the configuration of the light-receiving light guide section in the optical connection structure according to the first embodiment of the present invention; FIG. 7A is a schematic top view showing an example of the configuration of a light-receiving light guiding section in the optical connection structure according to the first embodiment of the present invention; FIG. 7B is a schematic side view showing an example of the configuration of the light-receiving light guide section in the optical connection structure according to the first embodiment of the present invention; FIG. 8A is a schematic top view showing an example of the configuration of a light-receiving light guiding section in the optical connection structure according to the first embodiment of the present invention; FIG. 8B is a schematic side view showing an example of the configuration of the light-receiving light guide section in the optical connection structure according to the first embodiment of the present invention; FIG. 9A is a schematic top view showing an example of the configuration of a light-receiving light guiding section in the optical connection structure according to the first embodiment of the present invention; 9B is a schematic side view showing an example of the configuration of the light receiving light guide section in the optical connection structure according to the first embodiment of the present invention; FIG. FIG. 10A is a schematic top view for explaining an optical connection structure according to a second embodiment of the invention. FIG. 10B is a schematic side view for explaining the configuration of the optical connection structure according to the second embodiment of the invention. FIG. 10C is a schematic top view for explaining the optical connection structure according to the second embodiment of the invention. FIG. 10D is a schematic side view for explaining the configuration of the optical connection structure according to the second embodiment of the present invention; FIG. 11 is a schematic side view for explaining the configuration of the second element in the optical connection structure according to the second embodiment of the invention. FIG. 12A is a schematic side view for explaining an example of the configuration of the optical connection structure according to the second embodiment of the invention; 12B is a schematic side view for explaining an example of the configuration of the optical connection structure according to the second embodiment of the present invention; FIG. FIG. 13A is a schematic top view for explaining an example of the method for manufacturing the optical connection structure according to the third embodiment of the present invention; FIG. 13B is a schematic side view for explaining an example of the method for manufacturing the optical connection structure according to the third embodiment of the present invention; FIG. 13C is a schematic side view for explaining an example of the method for manufacturing the optical connection structure according to the third embodiment of the present invention; FIG. 13D is a schematic top view for explaining an example of the method for manufacturing the optical connection structure according to the third embodiment of the present invention; FIG. 13E is a schematic side view for explaining an example of the method for manufacturing the optical connection structure according to the third embodiment of the present invention; FIG. 13F is a schematic top view for explaining an example of the method for manufacturing the optical connection structure according to the third embodiment of the present invention; FIG. 13G is a schematic side view for explaining an example of the method for manufacturing the optical connection structure according to the third embodiment of the present invention; FIG. 14A is a schematic top view for explaining the configuration of a conventional optical connection structure. FIG. 14B is a schematic top view for explaining the configuration of a conventional optical connection structure.

<First embodiment>
An optical connection structure according to a first embodiment of the present invention will be described with reference to FIGS. 1A to 9B.

<Configuration of Optical Connection Structure>
As shown in FIGS. 1A and 1B, the optical connection structure 10 according to the present embodiment includes a first substrate 111, a first element 11, a second element 12, and a first element 11 and a second element 11. A self-formed waveguide 131 (Self Written Waveguide: SWW) is provided between the element 12 of .

In the optical connection structure 10 , the first element 11 is a PLC chip and has a glass waveguide 113 . The glass waveguide 113 functions as a waveguide core and has a clad 112 around it.

An end face (hereinafter referred to as "glass waveguide end face") 117 at one end of the glass waveguide 113 is exposed toward the second element 12, and the other end is the first light receiving light guide part. 114. Hereinafter, in the PLC chip 11, the end face having the glass waveguide end face 117 is referred to as "PLC end face".

A waveguide branched from the glass waveguide 113 is connected to an optical circuit (not shown). Here, the optical circuit has functions such as multiplexing/demultiplexing and wavelength separation by the glass waveguide 113 .

Hereinafter, in the horizontal plane (substrate surface), the longitudinal direction (X direction in the drawing) of the glass waveguide 113 of the PLC chip 11 is defined as "waveguide direction", and the direction perpendicular to the longitudinal direction (Y direction in the drawing) is defined as " The direction (Z direction) perpendicular to the horizontal plane (substrate surface) is defined as the vertical (thickness) direction, and the side on which the glass waveguide 113 is arranged in the PLC chip 11 is defined as the “upper” direction. The substrate 111 side is the "downward" direction.

The first light-receiving light guide section 114 has a function of changing the course of a part of the light incident from the upper surface of the PLC chip 11 and making it exit from the glass waveguide end face 117 via the glass waveguide 113. formed by

The first substrate 111 on which the PLC chip 11 is formed has a recess 115, and the glass waveguide end face 117 is arranged above the side wall 115_2 of the recess 115.

The second element 12 is an LD chip and is formed on the second substrate 121 . The bottom surface (back surface) of the second substrate 121 of the LD chip 12 and the top surface of the recess 115 are brought into contact with each other and fixed.

The LD chip 12 includes an LD active layer 126, an InP waveguide 125, an SiN waveguide 123, and a second light receiving light guide section 124, as shown in FIG. 1C. Here, the surface on the InP waveguide 125 side is the front surface of the LD chip 12 , and the surface on the second substrate 121 side is the back surface of the LD chip 12 .

An InP waveguide 125 is connected to the LD active layer 126 , and the InP waveguide 125 is connected to the SiN waveguide 123 . The tip of the InP waveguide 125 has a tapered spot size converter (SSC).

In this embodiment, the InP waveguide 125 is covered with the SiN waveguide 123 and connected. Not limited to this, the InP waveguide 125 may be arranged close to the SiN waveguide 123, and may be arranged so that the laser light guided through the InP waveguide 125 is optically coupled to the SiN waveguide 123. .

An end face (hereinafter referred to as “SiN waveguide end face”) 127 at one end of the SiN waveguide 123 is exposed toward the first element (PLC chip) 11, and the other end faces the second receiving end. It connects to the light guide section 124 . Hereinafter, in the LD chip 12, the end face having the SiN waveguide end face 127 is referred to as "LD end face".

Similarly to the first light-receiving light-guiding portion 114 , the second light-receiving light-guiding portion 124 converts the optical path of the light incident from the upper surface, guides it to the SiN waveguide 123 , emitted from

In the self-formed waveguide 131 , one end face is connected to the glass waveguide end face 117 of the first element 11 and the other end face is connected to the SiN waveguide end face 127 of the second element 12 .

In the optical connection structure 10, the laser light emitted from the LD active layer 126 is guided through the InP waveguide 125 and the SiN waveguide 123 in order, is guided through the self-formed waveguide 131, and is guided through the glass. Incident into waveguide 113 .

Here, the reason why the InP waveguide 125 is connected to the SiN waveguide 123 is that the transmittance of visible light and ultraviolet light is low in InP but high in SiN, and is necessary for forming a self-forming waveguide described later. .

In the embodiment of the present invention, an example is shown in which the light receiving light guide section is arranged at the other end of both the first optical waveguide and the second waveguide, but it may be arranged at either one.

<Method for Manufacturing Optical Connection Structure>
In the method for manufacturing the optical connection structure 10, first, a photocurable resin is filled between the PLC end face of the PLC chip 11 and the LD end face of the LD chip 12, and the first light receiving light guide portion 114 and the second light receiving light guide portion are formed. Visible light (resin curing light) is incident on 124 from above.

This visible light (resin curing light) is emitted from the glass waveguide end surface 117 and the SiN waveguide end surface 127 on the wafer, and the photocurable resin is locally irradiated and cured to obtain the glass waveguide end surface 117 and the SiN waveguide end surface. 127 are connected in a self-aligning manner. After that, the self-forming waveguide 131 is formed by removing the unreacted photocurable resin. Finally, by dicing the wafer, the PLC chips 11 on which the LD chips 12 are mounted are formed.

Details of the method for manufacturing the optical connection structure 10 will be described below with reference to FIGS. 2A to 3. FIG.

First, the PLC chips 11 are formed on the wafer 1_1, and the concave portions 115 are formed in the substrate (FIGS. 2A and 2B).

Next, the LD chip 12 made from another wafer is mounted and fixed in the concave portion 115 (FIGS. 2C and 2D).

The mounting device can use a die bonder device, a flip chip device, a transfer printing device, etc. that can pick up a chip and mount it in a predetermined place by image recognition. As a bonding method, bonding using intermolecular force, bonding using epoxy resin, ultrasonic bonding of metal bumps for electrical conduction, fusion bonding using a thin solder film, and the like can be used.

In this process, variations occur in the height of the substrate in the vertical direction due to processing errors in the recesses and variations in substrate thickness of the LD chip 12 . Also, a positional deviation of about 3 microns occurs in the horizontal direction of the wafer.

Next, a photocurable resin 14 is formed by spin coating, and mask-exposed with an exposure device (FIG. 2E).

In the present embodiment, the upper surface of the exposure mask 161 is exposed from the upper surface of the exposure mask 161 with the resin curing light 15 of g-line (wavelength of 436 nm) in the exposure apparatus, and the resin curing light 15 passing through the opening 162 of the exposure mask 161 is the second The light is incident on the first light receiving light guide portion 114 and the second light receiving light guide portion 124 .

In the exposure mask 161 , the openings 162 are periodically arranged so as to correspond to the positions of the first light receiving light guiding portion 114 and the second light receiving light guiding portion 124 .

At this time, for example, a fine linear pattern is formed in the opening 162 to form a diffraction grating so that the resin curing light 15 passing through the exposure mask 161 has a directional component other than the vertical direction.

The resin curing light 15 enters the first light-receiving light guide portion 114 and the second light-receiving light guide portion 124 .

The resin curing light 15 incident on the first light receiving light guide portion 114 is guided by the glass waveguide 113 and emitted from the glass waveguide end surface 117 .

On the other hand, the resin curing light 15 incident on the second light receiving light guide portion 124 of the LD chip 12 is guided by the SiN waveguide 123 and emitted from the SiN waveguide end surface 127 .

As a result, the photocurable resin 14 is irradiated with the resin curing light 15 from both the glass waveguide 113 and the SiN waveguide 123, the self-forming waveguide 131 is formed, and the light is transmitted between the glass waveguide 113 and the SiN waveguide 123. A connection is made (FIG. 2F).

Next, a self-formed waveguide clad is formed around the self-formed waveguide 131 . For example, a self-forming waveguide cladding can be formed by using, as the photocurable resin 14, a resin that produces a difference in refractive index between a portion that is cured with ultraviolet rays and a portion that is cured with heat. Here, the refractive index of the heat-cured portion is lower than the refractive index of the ultraviolet-cured portion.

Specifically, a chemical reaction accompanying exposure progresses, the photocurable resin 14 is cured, and the self-formed waveguide 131 is formed. On the other hand, when the unreacted portion of the photocurable resin 14 is liquid, the entire resin including the liquid unreacted portion is thermally cured.

As a result, a difference in refractive index occurs between the portion cured by ultraviolet light and the portion cured by heat. The surrounding portion) has a lower refractive index than the self-forming waveguide 131 and becomes a cladding.

Alternatively, a self-formed waveguide clad may be formed around the self-formed waveguide 131 after removing the unreacted portion of the photocurable resin 14 .

Specifically, the unreacted photocurable resin 14 is removed by a developer device using a developer (FIG. 2G).

A cladding 132 of the self-formed waveguide 131 can then be formed by spin-coating and curing a material having a refractive index lower than that of the self-formed waveguide 131 (FIG. 2H).

Furthermore, after this process, electrical connection can be made from above by a rewiring process, wire bonding, or the like.

As described above, the optical connection structure 10 is formed on the wafer. Finally, the wafer (described later, FIG. 4A) on which the optical connection structure 10 is formed is diced.

Also, in the process of performing mask exposure with the exposure apparatus described above, as shown in FIG. The resin curing light 15) can be condensed and expanded.

FIG. 4A shows the wafer 1_2 on which the optical connection structure 10 is manufactured by the method described above. Also, FIG. 4B shows an enlarged view of a part of the wafer 1_2 (inside the dotted line in FIG. 4A).

In the optical connection structure 10, when the LD chip 12 is mounted at an angle (tilted) in the waveguide direction in the horizontal plane direction, in other words, even if the mounting position contains an error, the self-forming waveguide 131 allows the PLC chip 11 and the SiN waveguide 123 of the LD chip 12 are connected.

Since the self-formed waveguide 131 is formed so as to correct the positional deviation in this way, the mounting error (about ±3 microns) of the LD chip 12 is absorbed, and the LD chip 12 and the PLC chip 11 are connected with low loss. can be connected.

In the present embodiment, the same process and apparatus as the wafer process of a normal electric circuit can be used as a collective manufacturing method of the self-forming waveguide 131. It is advantageous for integrated mounting of chips made of different materials.

In this embodiment, the glass waveguide 113 and the SiN waveguide 123 are provided, but other materials may be used in combination as long as they transmit light having a wavelength that cures the photocurable resin 14 . In addition, Si and InP have a high transmittance of infrared light used for communication, but a low transmittance of visible light for curing. If a waveguide made of InP is connected, it can be used for communication.

<Modification>
An optical connection structure according to a modification of the first embodiment of the present invention will be described with reference to FIGS. 5A to 9B. This modification differs from the first embodiment in the configuration of the light-receiving light guide section in the optical connection structure.

In the optical connection structure according to this modified example, as shown in FIGS. 5A to 9B, the end of the glass waveguide 113 is provided with the first light-receiving light guiding portion 114 . One end of another glass waveguide 116 is connected to the glass waveguide 113, and the other end of the other glass waveguide 116 is connected to an optical circuit (not shown).

The refractive index of the other glass waveguide 116 may be the same as or different from the refractive index of the glass waveguide 113. If the refractive index of the other glass waveguide 116 is higher than that of the glass waveguide 113, the tip of the other glass waveguide 116 may have a tapered spot size converter (SSC). Further, the other glass waveguide 116 may be covered with the glass waveguide 113 and connected, or they may be arranged close to each other, and the

glass waveguides

113 and 116 are arranged so as to be optically coupled to each other. I wish I could.

In this modified example, the first light receiving light guide section 114 in the PLC chip 11 is taken as an example, but it may be applied to the second light receiving light guide section 124 in the LD12 chip.

The first light-receiving light guide section 114 may use a diffraction grating 21 as shown in FIGS. 5A and 5B. A metal film pattern is formed as the diffraction grating 21 . The resin curing light 15 incident from above the first light receiving light guide portion 114 is interfered (reflected) by the diffraction grating 21 and part of the resin curing light 15 is introduced into the glass waveguide 113 .

In addition, as shown in FIGS. 6A and 6B, a mirror 22 may be used for the first light receiving light guiding section 114. FIG. Here, the mirror 22 is formed in a part of the first light receiving light guiding section 114 . As a result, part of the resin curing light 15 reflected by the mirror 22 is introduced into the glass waveguide 113 .

The mirror 22 is configured by tilting the other end face of the PLC chip including the other end face of the glass waveguide 113 toward the substrate 111 .

Also, as shown in FIGS. 7A and 7B, a configuration using a lens structure 231 may be used. In this configuration, a condensing mirror is formed on the substrate 111 as the lens structure 231 .

First, recesses 233 are formed in the substrate 111 by etching.

Next, resin is placed on the corners of the bottom surface of the recess 233, and the surface tension of the resin makes the surface of the resin curved.

Finally, a thin metal film is deposited on the curved resin surface.

Thereby, a condensing mirror (lens structure) 231 made of resin is formed. A portion of the resin curing light 15 incident on the concave portion 233 is condensed toward the glass waveguide 113 by the condensing mirror 231 and is incident on the glass waveguide 113 . In order to confine this incident light in the glass waveguide 113, a metal mirror 232 may be arranged on the upper surface of the glass waveguide 113. FIG.

Also, as shown in FIGS. 8A and 8B, a crystal orientation plane (facet) 241 formed by wet etching the silicon substrate 111 may be used as a mirror. Considering that the angle 242 between the crystal orientation plane 241 and the horizontal plane is about 55 degrees, the crystal orientation is adjusted so that the resin curing light 15 reflected by the crystal orientation plane (mirror) 241 is incident on the glass waveguide 113. Design the position of the surface (mirror) 241 . A mirror 243 made of metal may be arranged on the upper surface of the glass waveguide 113 in order to confine the resin curing light 15 in the glass waveguide 113 .

In addition, if it is difficult to process an LD chip or the like, a mirror 251, which is an individual component, may be arranged on the substrate 111 as shown in FIGS. 9A and 9B. As a result, the resin curing light 15 from above is reflected in a direction of about 90 degrees with respect to the incident direction, so there is no need to consider the light path of the light receiving light guide section. Here, the process conditions are adjusted so that the mirror 251 does not come off during spin coating and can be removed after exposure and development.

<Second Embodiment>
An optical connection structure and a manufacturing method thereof according to a second embodiment of the present invention will be described with reference to FIGS. 10A to 12B.

In the first embodiment, an example is shown in which the self-forming waveguide 131 is formed and connected after mounting the first optical element (PLC chip) and the second optical element (LD chip). In the optical connection structure 20 according to the present embodiment, after forming the self-formed waveguide 131 on one chip (PLC chip), the structure of the self-formed waveguide 131 is used to improve the positional accuracy. . Other configurations are the same as those of the first embodiment.

<Configuration of Optical Connection Structure>
The optical connection structure 20 includes a PLC chip 11, an LD chip 12, and a self-forming waveguide 131 between the PLC chip 11 and the LD chip 12, as shown in FIGS. 10A-D.

Here, as shown in FIG. 11, the LD end face of the LD chip 12 is provided with a concave groove 31 having

openings

311 and 312 on the upper surface of the LD chip 12 and the LD end face, respectively. Also, the groove 31 is fitted with the self-forming waveguide 131 . Also, the LD chip 12 does not require a substrate. Other configurations are the same as those of the first embodiment.

<Method for Manufacturing Optical Connection Structure>
A method for manufacturing the optical connection structure 20 according to this embodiment will be described with reference to FIGS. 10A to 12B.

First, as shown in FIGS. 10A and 10B, after forming the PLC chip 11 and before mounting the LD chip 12, a self-forming waveguide 131 connected to the PLC chip 11 is formed with an appropriate length.

Next, as shown in FIGS. 10C and 10D, the LD chip 12 is mounted so that the SiN waveguide end surface 127 is connected to the self-formed waveguide 131. Then, as shown in FIGS. Here, the LD chip 12 has a layered structure including an LD active layer 126 other than the substrate, an InP waveguide 125, an SiN waveguide 123, and a clad by a wafer bonding method or the like. Here, it is not necessary to provide the LD chip 12 with the second light receiving light guide section 124 .

Also, the LD chip 12 has a groove 31 as shown in FIG. A SiN waveguide end surface 127 is exposed on the side surface of the groove 31 parallel to the LD end surface.

The self-formed waveguide 131 is fitted (inserted) into the groove 31 of the LD chip 12 to connect the exposed portion of the LD chip 12 and the self-formed waveguide 131 . At this time, the chips are mounted and bonded together with image recognition.

Also, as shown in FIGS. 12A and 12B, the LD chip 12 may be mounted with the opening 311 on the upper surface of the groove 31 facing the substrate 111 side. As a result, the position of the LD chip 12 in the vertical direction (perpendicular to the substrate surface) can be improved compared to the case where the opening 311 on the upper surface of the groove 31 of the LD chip 12 is directed upward (opposite to the substrate 111 side). Margins in alignment can be improved.

At this time, the LD chip 12 from which the substrate has been removed is formed into a thin film so as to transmit visible light, so that the LD chip 12 can be mounted close to the self-formed waveguide 131 from above using image recognition. can be done.

Also, if there is a manufacturing error in the vertical direction, by bending (or curving) the self-forming waveguide 131 toward the substrate side within a range that does not destroy it, good optical connection can be obtained.

According to the optical connection structure according to the present embodiment, the self-forming waveguide 131 formed in one optical element (PLC chip) 11 and the concave groove 31 formed in the other optical element (LD chip) 12 , optical connection can be made with high accuracy, and one optical element (PLC chip) 11 and the other optical element (LD chip) 12 can be mounted.

<Third Embodiment>
An optical connection structure according to a third embodiment of the present invention will be described with reference to FIGS. 13A to 13G.

In the first embodiment, an example is shown in which the self-forming waveguide 131 is formed and connected after mounting the chip. The optical connection structure according to the present embodiment is different in that after the self-formed waveguide 131 is formed in one chip (LD chip), the positional accuracy is enhanced using the structure of the self-formed waveguide 131 . Other configurations are the same as those of the first embodiment.

<Configuration of Optical Connection Structure>
The optical connection structure includes a PLC chip 11, an LD chip 12, and a self-forming waveguide 131 between the PLC chip 11 and the LD chip 12, as shown in FIG. 13G. Here, the PLC end surface of the PLC chip 11 is provided with a concave groove 41 having openings on the upper surface of the PLC chip 11 and the PLC end surface. Also, the groove 41 is fitted with the self-forming waveguide 131 . Other configurations are the same as those of the first embodiment.

<Method for Manufacturing Optical Connection Structure>
First, after the LD chips 12 are periodically arranged on the wafer and collectively formed, the substrate 121 is half-cut along the scribe lines to the middle of the substrate 121 to form the LD wafer grooves 42 .

Next, similarly to the manufacturing process in the first embodiment, the resin curing light 15 is incident from the second light receiving light guide portion 124 and emitted from the SiN waveguide end surface 127 to the LD wafer groove 42. The filled photocurable resin 14 is irradiated. Thereby, the resin is cured to form the self-formed waveguide 131 with an appropriate length. Next, the uncured portion around the self-formed waveguide 131 is removed (FIGS. 13A, B).

Next, the LD chip 12 is singulated by cleaving or the like (Fig. 13C).

On the other hand, as shown in FIGS. 13D and 13E, PLC chips 11 are formed on the wafer, and concave grooves 41 are formed on the PLC end faces. Here, the concave groove 41 has openings on the PLC end surface and the upper surface of the PLC chip 11 .

The upper surface of the LD chip 12 is directed (flipped) to the substrate 111 side, and the self-formed waveguide 131 is fitted into the concave groove 41 of the PLC end face, and the LD chip 12 is mounted and bonded to the concave portion 115 of the wafer (Fig. 13F, G).

At this time, the position of the SiN waveguide 123 on the LD chip 12 side cannot be grasped by direct image recognition from the back surface (substrate 121 side) of the LD chip 12, but since the self-formed waveguide 131 protrudes from the LD end face, image recognition , the position of the SiN waveguide 123 can be detected.

Furthermore, by fitting the self-formed waveguide 131 into the groove 41, it is possible to structurally improve the positional accuracy.

According to the optical connection structure according to the present embodiment, by fitting the self-forming waveguide 131 formed in one chip and the concave portion formed in the other chip, optical connection can be achieved with high accuracy. , can be loaded with one chip and the other. Further, when recognizing an image from the substrate side of the chip to be mounted, the position of the waveguide of the chip to be mounted can be grasped by the self-formed waveguide 131 projecting from the chip end and the image can be recognized.

In the embodiment of the present invention, an example of the structure, dimensions, materials, etc. of each component is shown in the configuration, manufacturing method, etc. of the optical connection structure, but the present invention is not limited to this. Any material may be used as long as it exhibits the function of the optical connection structure and produces an effect.

The present invention relates to an optical connection structure, and can be applied to devices and systems such as optical communication.

10 Optical Connection Structure 11 First Optical Element 111 First Substrate 113 First Waveguide 114 First Light Receiving Light Guide Section 12 Second Optical Element 123 Second Waveguide 131 Self-formed Waveguide

Claims

a first optical element disposed on a first substrate and having a first optical waveguide;
a second optical element having a second optical waveguide;
a self-forming waveguide connecting one end of the first optical waveguide and one end of the second optical waveguide;
an optical connection structure comprising: a first light receiving light guiding portion arranged at the other end of the first optical waveguide;
2. The optical connection structure according to claim 1, further comprising a second light-receiving light guide section arranged at the other end of the second optical waveguide.
At least one of the first light-receiving light guide section and the second light-receiving light guide section redirects at least a part of the light incident in the vertical direction of the first substrate to the horizontal direction of the first substrate. 3. The optical connection structure according to claim 2, further comprising a conversion structure for changing direction.
One end of the first optical element and the second optical element has a groove having an opening on one end surface facing the other end surface and on the upper surface,
Either one of the first optical waveguide and the second optical waveguide is exposed on a side surface of the groove parallel to the one end face,
The optical connection structure according to any one of claims 1 to 3, wherein the self-forming waveguide is mechanically fitted into the groove.
a first optical element having a first optical waveguide and a first light receiving light guide portion arranged at the other end of the first optical waveguide; a second optical waveguide; A method for manufacturing an optical connection structure for optically connecting a second optical element having a second light-receiving light guide portion arranged at an end, comprising:
collectively forming a plurality of the first optical elements on a first substrate;
a step of collectively forming a plurality of the second optical elements on a second substrate and chipping the second optical elements;
bringing the end surface of the first optical waveguide and the end surface of the second optical waveguide close to each other to fix the first optical element and the second optical element;
filling a photocurable resin between the end face of the first optical waveguide and the end face of the second optical waveguide;
exposing the resin curing light to enter the first light receiving light guide portion and the second light receiving light guide portion through the openings of the exposure mask, irradiating the photocurable resin with the resin curing light; forming a self-forming waveguide;
forming a clad having a lower refractive index than the self-formed waveguide around the self-formed waveguide.
6. The method of manufacturing an optical connection structure according to claim 5, wherein a diffraction grating is provided in the opening of the exposure mask.