JP2005331759A - Manufacturing method for device with optical waveguide structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a device having an optical waveguide structure with little optical transmission loss that enables an optical waveguide to be efficiently manufactured on a substrate. <P>SOLUTION: The method for manufacturing a device having, on a substrate, an optical waveguide structure which is composed of a core part transmitting light and a clad part comprising an upper and a lower clad part and surrounding the core part, is characterized in that it includes an unhardened lower clad part forming process in which an unhardened film for the lower clad part is press-fixed onto the substrate; a lower clad part forming process in which the lower clad part is obtained by hardening the unhardened film for the lower clad part; a core part forming process in which the core part is formed; and an upper clad part forming process in which the upper clad part is formed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a device with an optical waveguide structure.

  With the progress of the information processing field and the information communication field, the amount of data handled is increasing, and it is predicted that it will continue to increase in the future. Along with this, there is a demand for higher communication speed. For this reason, it is desired to shift to information processing and information communication using an optical signal whose processing speed is higher than that of an electrical signal. In particular, in recent years, not only signal transmission paths with long transmission distances typified by optical communication cables and dedicated devices associated therewith, but also short signal transmission paths such as connections of boards and electronic components in general-purpose electronic equipment, The transition from electrical transmission media to optical transmission media is being considered.

  As a technique for performing short signal transmission by optical communication, a technique for forming an optical waveguide on a substrate and exchanging signals is known. In general, an optical waveguide includes a core portion through which light propagates and a cladding portion that confines light in the core portion. Here, as a method for producing an optical waveguide on a substrate, a method of forming a lower clad portion, a core portion, and an upper clad portion on a substrate in order using a spin coating method is generally used. However, in the spin coating method, since the liquid photopolymerizable composition is directly applied, other components are mounted after the optical waveguide is formed, or on the substrate on which the other components are mounted. It was necessary to form an optical waveguide in consideration of the solution not being applied to other parts. Therefore, the formation positions of the optical waveguide and other parts are remarkably limited, and the manufacturing method is not efficient. Further, in the spin coating method, since the photopolymerizable composition to be the lower clad portion is in a liquid state before being cured, the unevenness of the substrate affects the shape of the optical waveguide, causing a light transmission loss. FIG. 10 is a cross-sectional view including an example of the core portion. In this device 190 with an optical waveguide structure, an optical waveguide 110 is formed on a substrate 130. The substrate 130 is a wiring substrate having the wiring 109 on the surface. The optical waveguide 110 is formed by sequentially applying and curing an uncured resin to be the lower clad part 121, the core part 104, and the upper clad part 122 by spin coating. However, the application of the uncured resin by spin coating generates a bulge 101 in the lower clad portion above the wiring 109, the core shape is not accurately formed, and this causes a light transmission loss.

  On the other hand, a method for transferring an optical waveguide previously produced on a transfer sheet onto a substrate has been developed. (For example, refer to Patent Document 2) However, since an optical waveguide is manufactured separately and then transferred onto a substrate, it takes time and is not an efficient method of manufacturing an optical waveguide. Further, since transfer is performed with the lower clad portion, the core portion, and the upper clad portion formed, light transmission loss occurs due to peeling during transfer, deformation of the core shape, and the like. FIG. 11 is a cross-sectional view including the core portion of the example. This is a manufacturing process in which the optical waveguide 210 is formed on the substrate 230 by transfer when the device 290 with an optical waveguide structure is manufactured. The substrate 230 is a wiring substrate having the wiring 209 on the surface. An optical waveguide 210 having a lower clad part 221, a core part 204, and an upper clad part 222 is formed on the release sheet 207. Then, after the optical waveguide 210 is transferred onto the substrate 230 in the direction of the arrow in FIG. 11, the release sheet 207 is peeled to form a device with an optical waveguide structure. However, in the upper part of the wiring 209, the deformation 201 of the optical waveguide occurs. In addition, a gap 202 or the like may occur during transfer. As a result, the core shape is not accurately formed, which causes a light transmission loss.

JP-A-9-236731 JP 2002-289911 A

  The present invention has been made in view of the above-described viewpoints, and an object of the present invention is to provide a method for manufacturing a device with an optical waveguide structure that can efficiently manufacture an optical waveguide on a substrate and has a small optical transmission loss.

In order to solve the above problems, a method for manufacturing a device with an optical waveguide structure of the present invention is as follows.
In a method of manufacturing a device with an optical waveguide structure comprising an optical waveguide structure on a substrate, the optical waveguide structure having a core portion through which light propagates, and an upper cladding portion and a lower cladding portion and surrounding the core portion,
An uncured lower clad part forming step of crimping an uncured film for the lower clad part on the substrate;
A lower clad part forming step of obtaining the lower clad part by curing the uncured film for the lower clad part;
A core part forming step for forming the core part;
An upper clad portion forming step for forming the upper clad portion;
It is characterized by providing.
According to the method of the present invention, it is not necessary to apply a liquid photopolymerizable composition directly onto a substrate as in the prior art, and it does not require man-hours, so that an optical waveguide can be produced efficiently. Furthermore, a core portion having an accurate pattern (substantially constant thickness) can be formed, and an optical waveguide with little transmission loss can be easily formed.

  An uncured film refers to a material that does not have fluidity at room temperature of 20 ° C. and is made of a photopolymerizable composition, and has a viscosity of 10 Pa · S or more. It may or may not be after obtaining the drying step. Furthermore, it is preferable that it is substantially solid, has no fluidity, does not have surface tackiness, and consists of a photopolymerizable composition. The phrase “substantially solid and non-fluid” means that it does not contain a solvent component (excluding those that are inevitably removed in production) and can maintain the applied molding state. . Further, “having no surface tackiness” means that it does not have a sticky feeling when the surface of the film body is touched at room temperature. Specifically, at room temperature (about 25 ° C.), a 1 cm wide PET film (thickness: 38 μm) is attached to the surface of the film body (the side where the support is not formed), and the PET film is oriented in the direction of 90 degrees. The peel strength when peeled at a speed of 50 mm / min can be 0.3 kN / m or less.

  In the uncured lower clad portion forming step, an uncured lower clad portion is formed by pressure-bonding an uncured film for a lower clad portion formed on a peelable support to a substrate and then peeling the support. Can do. A laminating method, a pressing method, or the like can be employed as the method for pressure bonding. The laminating method is a method of pressing a film by rolling a roll from one side of the support to the other side. When this method is used, it is possible to reduce the entrainment of bubbles because pressure can be applied while extruding air. In particular, the laminating method can efficiently crimp an uncured film. Further, there is no gap between the substrate and the uncured film for the lower cladding part, and it is possible to form an optical waveguide with little leakage light. On the other hand, the press method is a method in which the entire film is simultaneously pressure-bonded using, for example, a rubber plate or a metal plate over the entire film to be attached. When this method is used, since the whole film can be pressure-bonded at once, the whole uniformity can be maintained. In addition, when an optical path conversion unit to be described later is formed, it is possible to accurately form an optical waveguide by suppressing the positional deviation of the optical path conversion unit.

  In press-bonding, heating or pressurization may be performed to stabilize the uncured film. Each condition such as heating and pressurization can be adjusted as appropriate. For example, it can be heated and pressure-bonded at a temperature of 20 to 130 ° C. Moreover, an uncured film can be formed more accurately by pressurizing under conditions of 0.1 to 2.4 MPa. It is also possible to perform the surrounding environment under reduced pressure so that bubbles are not involved during the pressure bonding. In the case of disposing by holding under reduced pressure, for example, it can be performed under conditions such as a pressure of 0 to 500 mmHg and a reduced pressure time of 1 second to 10 minutes.

  In the uncured lower clad part forming step, a curing method of curing the uncured film for the lower clad part can be employed by photocuring, heat curing, combined use of photocuring and heat curing, or the like. When completely cured only by photocuring, the lower clad portion can be obtained only by photocuring. It is also possible to form a core part and an upper clad part, which will be described later, after forming the lower clad part that is not completely cured only by photocuring (so-called semi-cured). A fully cured lower clad portion can also be obtained by carrying out a main curing step by thermal curing after photocuring. Here, “cured” includes a semi-cured state and a completely cured state.

  In the core part forming step, a core part is formed on the lower clad part. First, an uncured core part material is formed on the lower clad part. Thereafter, the photopolymerizable composition constituting the uncured core portion material is cured (polymerized) to form the core portion. Any method may be adopted for curing, but a predetermined portion is selectively cured by a normal photolithography method to form a core portion patterned in a predetermined shape. The above-mentioned “photolithography method” means that a desired core part pattern is exposed using predetermined light, a desired part of an uncured core part is cured, and then the part that is not cured without being irradiated with the light. A method comprising the step of removing. Specifically, this step will be described. A predetermined light is irradiated through a photomask having a predetermined pattern, and only a portion irradiated with the light through the photomask pattern is cured. Thereafter, the uncured portion is removed using a developer, whereby a core portion patterned in a predetermined shape is formed on the lower clad portion.

  As the core part material, it is preferable to use an uncured film for the core part and to form it by pressure bonding in the same manner as the uncured lower clad part forming step. Since the material resin does not ooze out from the film prepared in advance, it can be attached at a predetermined position, so that the thickness can be made constant. At this time, in the uncured film for the core portion, when the above-described peeling strength is 0.3 kN / m or less, the core portion having an accurate pattern is formed when the core portion of the optical waveguide is formed by photolithography. Can be formed. The peel strength is more preferably 0.2 kN / m or less, and further preferably 0.1 kN / m or less. Thus, when the core part is formed using an uncured film for a core part that does not contain a solvent and is substantially solid and has no fluidity, the shape of the core part does not collapse as in the prior art, and the length is long. A core part having an accurate pattern in which the shape of a cross section perpendicular to the direction (light propagation direction) is substantially rectangular or substantially square can be formed. Moreover, since this uncured film for core part does not have surface adhesiveness, when irradiating light, a photomask can be arrange | positioned directly on a film body. In this case, a core portion having a more accurate pattern can be formed, which is preferable.

  As a curing method for using the uncured core portion material as the core portion, a method similar to the curing method in the uncured lower clad portion forming step can be employed.

  In the upper cladding part forming step, a core part is formed on the core part. First, an uncured material for the upper cladding part is formed on each surface of the core part and the lower cladding part. As the uncured material for the upper clad part, it is preferable to use an uncured film for the upper clad part and to form it by pressure bonding similarly to the uncured lower clad part forming step. Thereafter, the upper clad portion is formed by the same method as the curing method in the uncured lower clad portion forming step. In addition, it is also possible to form an intermediate clad part that covers the side surface of the core part and to form an upper clad part on the intermediate clad part and the upper surface of the core part. In this case, the clad part surrounding the core part is composed of a lower clad part, an intermediate clad part, and an upper clad part.

When at least one of the lower clad part, the core part, and the upper clad part is not completely cured (so-called semi-cured), it is preferable to provide a main curing step of performing main curing after the upper clad portion forming step. After mounting the optical waveguide on the substrate, when mounting other components, the optical waveguide may be deformed by heat. In particular, when a light emitting element, a light receiving element or the like is mounted on the optical waveguide, the optical waveguide is deformed by heat at the time of mounting, which causes an optical axis shift or the like. Therefore, by forming a completely cured optical waveguide by the main curing process before mounting other components, it is possible to obtain an optical waveguide with little light transmission loss.
In addition, it is possible to propagate light as an optical waveguide without completely curing the lower clad part, the core part, and the upper clad part (so-called semi-cured). In this case, a main curing step (collective curing step) for performing the main curing at once can be provided. In this case, the main curing (usually thermosetting) may be performed once and an efficient production method can be obtained.

  The substrate is not particularly limited as long as an optical waveguide is formed. Examples of the material constituting the substrate include organic materials, inorganic materials, and composite materials using both. In order to form an optical waveguide by forming an optical waveguide, the substrate is preferably a wiring substrate. In this case, the wiring (conductor portion) may be formed in the inner layer as an internal conductor, or may be formed in the surface layer. A multilayer wiring board in which wiring layers and insulating layers are alternately formed is also possible. Even if the flatness of the substrate surface is not maintained by the wiring (conductor portion), according to the manufacturing method of the present invention, the upper surface of the lower clad is flattened by pressing the uncured film for the lower clad portion, and the core portion Can be formed on the lower clad having sufficient flatness. This is effective in reducing optical transmission loss.

  Furthermore, in the method for manufacturing a device with an optical waveguide structure according to the present invention, in addition to the above steps, a step of mounting other components such as an optical component such as a light emitting element and a light receiving element, various electronic components, and the conductor portion The process of arrange | positioning can be provided.

It is preferable that other components are mounted on the substrate from the viewpoint of enhancing the functionality of the device with an optical waveguide structure. Even on such a substrate, the optical waveguide can be efficiently formed on the substrate by the production method of the present invention.
Further, it is preferable that the substrate has a cavity portion from the viewpoint of reducing the height of the device with an optical waveguide structure. Even on such a substrate, the optical waveguide can be efficiently formed on the substrate by the production method of the present invention.

As said light emitting element, a surface emitting laser (Vertical Cavity Surface Emitting Laser; VCSEL), a light emitting diode (Light Emitting Diode; LED), a semiconductor laser diode (Laser Diode; LD) etc. are mentioned, for example. These may use only 1 type and may use 2 or more types together.
Examples of the light receiving element include a pin photodiode (pin PD) and an avalanche photodiode (APD). These may use only 1 type and may use 2 or more types together. The light emitting element and the light receiving element may be integrated.
Furthermore, examples of electronic components include driver ICs, MPUs, various active components (such as integrated circuit elements and transistors), passive components (such as capacitors, capacitors, and inductors), conversion components (such as filters and transformers), and connection components. . These may use only 1 type and may use 2 or more types together.
The method for mounting these optical components and electronic components is not particularly limited, and may be wire bonding and / or flip chip bonding.

  The device with an optical waveguide structure can further include a conductor portion. In particular, when an optical element such as the light emitting element and the light receiving element is provided, it is preferable to include a conductor portion. By providing the conductor portion, the optical element can be electrically connected to other electronic components, and the optical waveguide, the optical element, the electronic component, and the like can be handled as an integrated object. Further, by providing the conductor portion in the device with the optical waveguide structure, the connection distance between the optical element and the electronic component can be kept short, and the responsiveness can be improved. Furthermore, this contributes to miniaturization of the device with an optical waveguide structure itself. According to this manufacturing method, it is possible to efficiently create an optical waveguide while avoiding the conductor portion. Alternatively, it is possible to create an optical waveguide on the conductor portion without any light transmission loss.

  When optical path conversion is required as a device with an optical waveguide structure, it is preferable to include an optical path conversion unit. The “optical path changing part” is a part that is formed on the substrate and reflects light propagating in the core part. By having this optical path conversion unit, it is possible to efficiently convert the optical path while preventing light leakage. Only one optical path changing unit may be arranged in a device with an optical waveguide structure, or two or more optical path changing units may be arranged. Note that “on the substrate” means above the substrate, and the optical path conversion unit may be disposed on the surface of the substrate or may be disposed on the surface of the lower clad portion.

The step of forming the optical path changing portion can be obtained by pressing a metal lump against the pad portion and then forming the metal lump into a predetermined shape using a stamping jig. In addition, the optical path conversion unit can be formed by arranging optical path conversion parts molded in a predetermined shape in a predetermined position. The method for manufacturing the optical path conversion component is not particularly limited. For example, the optical path conversion part can be obtained by peeling the substrate after forming the optical path conversion portion on the surface of the peelable substrate or the like. Further, it can be produced by a general metal working method such as casting / forging.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[1] Device with optical waveguide structure 100
FIG. 1 is a diagram schematically showing a cross section of an example of a device with an optical waveguide structure of the present invention. Moreover, FIG. 2 is a figure which shows typically the AA cross section in FIG. The device with an optical waveguide structure includes a substrate (multilayer ceramic wiring substrate) 3, a lower clad part 21, a core part 1, an upper clad part 22, and optical path changing parts 41 and 42.

  The core unit 1 is optically path-converted by the optical path converters 41 and 42. Moreover, the core part 1 is comprised from the epoxy-type resin. On the other hand, the upper clad part 22 and the lower clad part 21 are made of an epoxy resin having a refractive index smaller than that of the core part 1.

  The substrate (multilayer ceramic wiring substrate) 3 has an internal conductor (not shown) (via hole and through hole for wiring connection and interlayer connection) and alumina-based sintered material, and these conductor portions are alumina-based sintered material. It is insulated by. A lower clad portion 21 and the like are provided on one surface side of the substrate 3, and a plurality of connection terminals (conductor portions 82) are provided on the other surface side. The conductor portion 82 is a connection terminal for mounting the device 100 with an optical waveguide structure on a printed wiring board (not shown), and is made of gold, silver, copper, solder, aluminum, nickel, an alloy thereof, or the like.

  Further, as the optical path conversion section, triangular path-shaped optical path conversion sections 41 and 42 made of gold and having inclined surfaces of about 45 ° facing each other are provided. These optical path conversion units 41 and 42 are arranged on one surface of the substrate 3. Further, the uppermost portions of the optical path changing portions 41 and 42 are formed so as to be flush with the upper surface of the core portion 1 or protrude from the upper surface of the core portion 1.

[2] Device with optical waveguide structure 200
FIG. 3 is a diagram schematically showing a cross section (BB cross section of FIG. 4 described later) of an example of the device with an optical waveguide structure of the present invention. The device with an optical waveguide structure 200 includes a conductor portion 81 for connecting the light emitting element 61 and the light receiving element 62 to an electric circuit (not shown) as conductor portions on the upper clad portion 22 of the device with an optical waveguide structure 100. . The conductor portion 81 is made of gold, silver, copper, solder, aluminum, nickel, an alloy thereof, or the like.

Further, the optical element includes a VCSEL that is the light emitting element 61 and a photodiode that is the light receiving element 62. The light emitting element 61 can emit predetermined light such as ultraviolet rays and near infrared rays, and the light receiving element 62 can detect these lights. The light emitting element 61 includes a light emitting portion, and is mounted with the light emitting portion facing downward. On the other hand, the light receiving element 62 includes a light receiving portion, and is mounted with the light receiving portion facing downward. Each optical element is bonded via a conductor portion 81 formed on the surface of the upper clad portion 22.
Each of these optical elements receives an electrical signal from an external circuit (not shown) and is converted into an optical signal by the light emitting element 61. Light emitted as an optical signal from the light emitting element 61 is transmitted through the core portion 1 to receive the light. Light is received at 62. The optical signal received by the light receiving element 62 is converted into an electric signal by the light receiving element 62 and transmitted to an external circuit (not shown).

FIG. 4 is a schematic view showing the device with an optical waveguide structure 200 from the upper surface direction of the substrate. In the substrate 3, a cavity portion 56 is formed on a substrate on which the optical waveguide 29 (optical waveguide structure) is not formed, and a driver IC 51 is mounted inside the cavity portion 56. An MPU 52 for arithmetic processing is mounted on the substrate 3 and is connected to the driver IC 51 by wiring 54 on the substrate. The driver IC 51 is connected to the light emitting element 61 via a via conductor (not shown) in the optical waveguide, a conductor portion 81 on the optical waveguide, and the like by wiring 53 (which may be an internal conductor) on the substrate. Thereby, the driver IC 51 controls the optical signal of the light emitting element 61. The driver IC 51 and MPU 52 are mounted by known wire bonding or flip chip bonding.

[3] Manufacturing method 1 of device with optical waveguide structure (manufacturing method by sequential curing)
An example of the manufacturing method of the device with an optical waveguide structure 100 described in the above [1] will be described below. In the following description of the manufacturing method, for the sake of convenience, each part will be described using the reference numerals of the device with the optical waveguide structure after manufacturing.
(1) Substrate 3
As the substrate 3, a multilayer ceramic wiring substrate sintered in advance was prepared. The configuration of the multilayer ceramic wiring board is as described above. A cavity portion 56 for mounting the driver IC 51 is formed in advance on the upper surface of the substrate 3. In addition, wirings 53 and 54 for connecting the driver IC and the MPU 52 and the driver IC and the optical element are formed on the substrate in advance. And driver IC51 and MPU52 were mounted in the desired position of the board | substrate by the well-known method.

(2) Formation of pads and the like for the optical path conversion unit (Step 1 in FIG. 5)
Attaching a dry film (plating resist) to one side of the substrate 3, protecting the area other than forming the pad by exposure and development with a dry film, then performing gold plating, and finally peeling off the dry film (plating resist) Thus, the optical path conversion part pads 411 and 421, the positioning reference pad 91, and the wiring (conductor part) 93 were formed. In addition, the positioning reference pad 91, the wiring (conductor portion) 93, and the thin film made of gold that forms the optical path conversion unit pads 411 and 421 for forming the optical path conversion unit are releasably held on the surface of the release sheet. It is also possible to prepare a transfer film and transfer the transfer film to the surface of the multilayer ceramic wiring board.

(3) Uncured lower clad formation process (process 2 in FIG. 5)
Epoxy compound [alicyclic epoxy compound (Daicel Chemical Industries, product name “EHPE3150”) 99.5% by mass and polymerization initiator (acid generator, Asahi Denka Kogyo Co., Ltd., product name “SP172”) 0 .5 mass%] is mixed with a solvent (methyl ethyl ketone) and dissolved to prepare a mixed solution (solid content: 78%), and then obtained. The mixed solution is coated on a release sheet (PET film, thickness: 38 μm) by a casting method (gap: 130 μm), and then dried by heating (conditions: 120 ° C. × 30 minutes) to remove the solvent. An uncured film for forming a clad part (an uncured film for forming a lower clad part and an uncured film for forming an upper clad part) thus obtained was prepared.
This uncured film for forming the lower cladding part is placed on the laminate obtained up to (2) above, and only the uncured film for forming the lower cladding part is subjected to conditions of a temperature of 40 to 50 ° C. and a pressure of 0.5 MPa. And dried under conditions of a temperature of 120 ° C. for 30 minutes.

(4) Optical path conversion component embedding process (process 3 in FIG. 5)
First, a gold wire was supplied into a capillary provided in the wire bonding apparatus, and the tip of the gold wire was made into a lump. And after arrange | positioning the metal lump on the optical path conversion part formation board | substrate, this lump of metal was shape | molded into the predetermined shape using the stamping jig, and it was set as the optical path conversion component. Thereafter, the optical path conversion component is placed on the uncured lower clad portion 20 while positioning so as to be accurately placed on the optical path conversion portion pads 411 and 421 based on the coordinates of the positioning reference 91 using the image means. did. Thereafter, the resin was softened by heating to a temperature of 120 ° C., and the optical path conversion component was submerged in the uncured lower cladding by its own weight, and the optical path conversion component was embedded in the uncured lower cladding.

(5) Curing of the uncured lower clad portion (step 4 in FIG. 5, step 4 in FIG. 6)
The laminate obtained up to the above (4) was exposed (exposure amount: 2000 mJ / cm ² , light source: ultraviolet lamp, exposure time: about 7 minutes). Next, heating is performed at 120 ° C. for 30 minutes as post-baking, and further curing is performed by heating at 150 ° C. for 1 hour as main curing to form the lower cladding portion 21, the substrate 3, the lower cladding portion 21, It was set as the laminated body provided with the optical path conversion parts 41 and 42. FIG.

(6) Core part formation process (process 5 of FIG. 6)
Epoxy compound [aromatic epoxy compound (Japan Epoxy Resin Co., Ltd., product name “Epicoat 1001”) 44.5% by mass, alicyclic epoxy compound (Daicel Chemical Industries, Ltd., product name “EHPE3150”) 0 mass%] and a polymerization initiator (acid generator, manufactured by Asahi Denka Kogyo Co., Ltd., product name “SP172”) 0.5 mass% and a solvent (methyl ethyl ketone) are mixed and dissolved. A mixed solution (solid content: 78%) was prepared, and then the obtained mixed solution was coated on a support (PET film, thickness: 38 μm) by a casting method (gap: 130 μm), and then heated. An uncured film for forming a core part obtained by drying (conditions: 120 ° C. × 30 minutes) and removing the solvent was prepared.
This uncured film for forming the core part is placed on the lower clad part 21 and the optical path changing parts 41 and 42 of the laminate obtained up to the above (5), and the temperature is 40 to 50 ° C. and the pressure is 0.5 MPa. Only the uncured film for forming the core part was pressure-bonded onto the lower clad part 21 under the conditions and dried under the condition of a temperature of 50 ° C. × 30 minutes to form the uncured core part 10.
Next, a photomask on which a predetermined pattern (line width; about 50 μm) is formed is placed on the obtained uncured core portion, and exposure (exposure amount: 500 mJ / cm ² , light source: ultraviolet lamp, exposure time: about 2 minutes) and post-baked at a temperature of 120 ° C. for 30 minutes. Next, development (30 seconds) was performed using 2-methoxyethanol, washing with isopropyl alcohol (IPA), and the uncured core portion was patterned and cured simultaneously to form the core portion 1. Thereafter, the main curing was performed at 150 ° C. for 1 hour to completely cure.

(7) Upper clad portion forming step (step 6 in FIG. 6)
The same uncured film for forming a clad part (uncured film for forming an upper clad part) as used in (3) above was prepared.
Thereafter, the uncured film for forming the upper clad part is placed on the core part 1 and the lower clad part 21 of the laminate obtained up to the above (6), and only the uncured film for forming the clad part is heated. It pressure-bonded on 40-50 degreeC and the conditions of pressure 0.5MPa, and dried on the conditions of temperature 50 degreeC x 30 minutes.
Next, the obtained laminate was exposed (exposure amount: 2000 mJ / cm ² , light source: ultraviolet lamp, exposure time: about 7 minutes). Subsequently, it heated at 120 degreeC as a post-baking for 30 minutes, and also was made to harden by heating at 150 degreeC for 1 hour as main hardening, and the upper clad part 22 was formed. Thereafter, the main curing was performed by heating at 150 ° C. for 1 hour to completely cure, thereby obtaining the device 100 with an optical waveguide structure of the present invention.

[4] Manufacturing method 2 of device 100 with an optical waveguide structure (manufacturing method using a batch curing process)
An example of the manufacturing method of the device with an optical waveguide structure 100 described in the above [1] will be described below. In the following description of the manufacturing method, for the sake of convenience, each part will be described using the reference numerals of the device with the optical waveguide structure after manufacturing.
(1) Optical path conversion component embedding process, etc. (process 1 to process 3 in FIG. 7)
In the same manner as in the above [3] (1) to (4), the optical path changing parts 41 and 42 were formed in the uncured lower clad part 20.

(2) Uncured lower cladding part semi-curing step (step 7 in FIG. 7, step 7 in FIG. 8)
The laminated body obtained up to (1) above is exposed (exposure amount: 2000 mJ / cm ² , light source: ultraviolet lamp, exposure time: about 7 minutes), cured by heating at 120 ° C. for 30 minutes as a post-bake, and uncured The lower clad part 20 was semi-cured to form a semi-cured lower clad part 21.

(3) Core part formation process (process 5 of FIG. 8)
In the same manner as in the above [3] (6), the core portion 1 was formed on the semi-cured lower clad portion.

(4) Uncured upper clad portion forming step (step 8 in FIG. 8)
The same uncured film for forming the upper clad part (uncured film for forming the upper clad part) same as that used in the above [3] (3) is prepared. It mounted on the upper and lower clad part 21, and only the uncured film for upper clad part formation was crimped | bonded on the conditions of temperature 40-50 degreeC and the pressure of 0.5 MPa, and it dried on the conditions of temperature 120 degreeC x 30 minutes.

(5) Batch curing process (process 9 in FIG. 8)
The laminate obtained up to the above (4) was exposed (exposure amount: 2000 mJ / cm ² , light source: ultraviolet lamp, exposure time: about 7 minutes). Next, heating is performed at 120 ° C. for 30 minutes as post-baking, and further heating is performed at 150 ° C. for 1 hour as main curing to further cure each of the semi-cured lower cladding portion 21, the core portion 1, and the uncured upper cladding portion 23. The device 100 with an optical waveguide structure of the present invention was obtained.

[5] Manufacturing Method of Device 200 with Optical Waveguide Structure An example manufacturing method of the device 200 with an optical waveguide structure described above will be described below. In the following description of the manufacturing method, for the sake of convenience, each part will be described using the reference numerals of the device with the optical waveguide structure after manufacturing.
(1) Formation of conductor portion 81 and positioning reference pad 92 (step 10 in FIG. 9)
A dry film (plating resist) is attached to the surface of the upper clad part 22 of the device 100 with an optical waveguide structure obtained in the above [3] and [4], and a pad is formed by exposure and development. After protection, gold plating was performed, and finally the dry film (plating resist) was peeled off to form the conductor portion 81 and the positioning reference pad 92. In addition, a transfer film in which a thin film made of gold that becomes the conductor portion 81 and the positioning reference pad 92 is releasably held on the surface of the release sheet is prepared. It is also possible to transfer and form the transfer film on the surface of the upper clad portion 22 at a position determined based on the position.

(2) Mounting of the light emitting element 61 and the light receiving element 62 (step 11 in FIG. 9)
Based on the positioning reference 92 using the same image means as described above, the light emitting element 61 is accurately placed on the conductor portion 81 at the target position, and the conductor portion is formed by solder provided on one surface of the light emitting element 61 in advance. 81. Similarly, based on the positioning reference 92, the light receiving element 62 was mounted and similarly connected by soldering to obtain the device 200 with an optical waveguide structure of the present invention. The difference in refractive index (core portion-cladding portion) between the obtained core portion 1 and each of the clad portions 21 and 22 is 1.9% for 850 nm near-infrared light and 2 for the 589 nm Na-D line. 0.0%.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can be implemented in various modes within the scope not changing the gist of the invention. For example, the semi-cured core part in which the core part in the collective curing process in Step 9 of FIG. 8 is not completely cured may be used. Prior to the collective curing step in step 9 of FIG. 8, the uncured upper clad portion may be made a semi-cured upper clad portion by the same process as the uncured lower clad semi-cured step of [4] (2). .

The “photopolymerizable composition” constituting the uncured film is polymerized by irradiation with predetermined light such as ultraviolet rays, infrared rays, and near infrared rays (“polymerization” includes “copolymerization” and “homopolymerization”. )) (Meaning that “polymerization has further progressed”) is cured to form a photo-curing resin, which becomes a clad part and a core part. The photocurable resin referred to in the present invention includes a thermosetting polymer ("polymer" includes "copolymer" and "homopolymer", the same shall apply hereinafter), a thermoplastic polymer, and the like. Further, the presence or absence of a three-dimensional structure in the resin is not limited.
The component contained in this photopolymerizable composition contains a photopolymerizable compound and a polymerization initiator.
Examples of the “photopolymerizable compound” include, for example, epoxy compounds, acrylic compounds, fluorine compounds, imide compounds, bismaleimide compounds, phenylene compounds, phenylene ether compounds, phenol compounds, silicone compounds, Examples include urethane compounds, ester compounds, phenoxy compounds, and olefin compounds. These compounds may use only 1 type and may use 2 or more types together. Among these, acrylic compounds and epoxy compounds are preferable. When the photopolymerizable composition contains an epoxy compound, an optical waveguide excellent in heat resistance, insulation, chemical resistance and water resistance can be obtained, and when it contains an acrylic compound, it is photosensitive and transparent. This is because an excellent optical waveguide can be obtained.

  Further, among these photopolymerizable compounds, an uncured film can be easily obtained by using a solid material as a main component at room temperature. At this time, blending of various commercially available materials and the like is adjusted according to desired characteristics.

Examples of the “polymerization initiator” include an acid generator and a radical generator. These polymerization initiators are appropriately selected according to the type of the photopolymerizable compound.
Moreover, when the said photopolymerizable compound is an epoxy-type compound, it is preferable to use an acid generator as a polymerization initiator.
When the photopolymerizable compound is an acrylic compound, it is preferable to use a radical generator as a polymerization initiator.

  The mass ratio (photopolymerizable compound / polymerization initiator) between the photopolymerizable compound and the polymerization initiator is not particularly limited, but is preferably 100 / 0.05 to 100/10, more preferably 100. /0.1 to 100/5, more preferably 100 / 0.2 to 100/4. When this mass ratio is 100 / 0.05 to 100/10, an optical waveguide having excellent heat resistance, insulation, chemical resistance and water resistance can be obtained by sufficiently proceeding the polymerization reaction.

  Further, the photopolymerizable composition can contain a photosensitizer according to the type of light irradiated when it is cured. The photosensitizer has a sensitizing action on the irradiated light and can assist the polymerization initiator. This photosensitizer is effective when it is difficult to obtain sufficient photosensitivity to the irradiated light with only a polymerization initiator or the like. Furthermore, a thermal polymerization initiator can be contained in order to finally heat cure after curing with light.

  Examples of the “photocuring resin” include epoxy resins, acrylic resins, fluororesins, polyimide resins, bismaleimide resins, polyphenylene resins, polyphenylene ether resins, phenol resins, silicone resins, urethane resins. , Polyester resins, phenoxy resins, and polyolefin resins. In addition, each halogenated resin in which at least a part of hydrogen atoms included in each of these resins is substituted with a halogen atom (F, Cl, Br, etc.), and at least a part of hydrogen atoms included in these resins are deuterium atoms. Examples include substituted deuterated resins. Only one kind of these resins may be used, or two or more kinds may be used in combination. Of these, epoxy resins and acrylic resins are preferable. When the core part is made of an epoxy resin, a device with an optical waveguide structure that is particularly excellent in heat resistance, insulation, chemical resistance, and water resistance is obtained. Further, when the core portion is made of an acrylic resin, a device with an optical waveguide structure that is particularly excellent in photosensitivity and transparency is obtained.

The method for producing the uncured film is not particularly limited. For example, the photopolymerizable composition and a solvent are mixed and dissolved to prepare a mixed solution, and then the obtained mixed solution is placed on the support. It can be manufactured by coating and then drying to remove the solvent.
Although the thickness of an uncured film is not specifically limited, It is preferable that it is 150 micrometers or less, More preferably, it is 20-80 micrometers, More preferably, it is 40-60 micrometers. In particular, it is often adjusted to about 50 μm according to the diameter of the multimode optical fiber.

The solvent is not particularly limited. For example, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and acetone, alcohol solvents such as methanol, ethanol and n-butanol, aromatic solvents such as xylene, toluene and benzene, aliphatic hydrocarbons such as hexane and pentane Examples of the solvent include phenol solvents such as phenol and cresol, and ether solvents such as diethyl ether and methoxytoluene.
The blending amount of the solvent is not particularly limited, but is preferably 40 to 90% by mass, more preferably 60 to 85% by mass when the total of the photopolymerizable composition and the solvent is 100% by mass. is there.

  A method for coating the mixed solution on the support is not particularly limited, but a casting method is preferably used. In this case, there is little raw material loss and productivity can be improved.

  The drying means for removing the solvent is not particularly limited, and examples thereof include heat drying and reduced pressure drying. In addition, each drying condition is suitably adjusted according to the component to contain.

Although the form of a core part is not specifically limited, Usually, it has an end surface which can input and output light. The number of the end faces is not particularly limited, but is usually two or more, and at least one can be used as a light entrance surface and at least one other can be used as a light exit surface. In the case of having three or more end faces, the core portion can have two or more light incident surfaces and / or light exit surfaces.
The planar shape is not particularly limited, and may be linear, curved, may have a bent portion, or may have a branch. Furthermore, it can also be set as the trumpet shape etc. which spread toward an end surface in the vicinity of an edge part. Among these, the bent portion means a portion where the optical path is bent. By having the bent portion, an optimal optical path can be obtained, and communication efficiency can be improved and the size can be reduced. This bent part may have only one place in a series of core parts, or may have two or more places. In the case where the core portion has a bent portion, an optical path changing portion described later is usually used.
Furthermore, the shape of the cross section perpendicular to the longitudinal direction of the core (the direction in which light propagates) is not particularly limited. In particular, in this device with an optical waveguide structure, a core portion having an accurate pattern can be formed, and the shape of the core portion can be substantially rectangular or substantially square.

  The refractive index of the core part may be a substantially uniform refractive index or may have different parts regardless of the type of resin constituting the core part and the number of types. . Note that the core portion has a portion with a different refractive index, for example, when the refractive index at the center of the core portion is maximum and the refractive index decreases as it approaches the cladding portion. Further, the refractive index may be different or the same between different types of resins, and even a resin derived from the same monomer changes depending on the degree of polymerization. Therefore, the uniform refractive index portion and the different refractive index portion may be obtained from the same kind of resin or from different kinds of resins.

  The light transmission characteristics of the core portion are not particularly limited, and any light such as infrared rays (including near infrared rays), visible rays, and ultraviolet rays can be transmitted.

As described above, the “cladding portion” is a portion that surrounds the core portion, and is a portion that can reflect light propagating in the core portion at the interface with the core portion. For example, the clad portion can obtain this effect by making the refractive index smaller (usually 0.2% or more) than the core portion.
The material constituting the clad portion is not particularly limited. An inorganic material may be used for this clad part, but it is easy to process, and it is easier to match the thermal expansion coefficient with the photopolymerizable composition that is cured to form the core part. It is preferable to use a system material. As the organic material, it is possible to use the resins mentioned as the photo-curing resin. However, the core part and the clad part may be made of the same resin or different resins.

  The configuration, shape, and the like of the optical path conversion unit are not particularly limited. For example, it can be configured by providing an inclined reflecting surface (for example, using one surface such as a V-shaped groove, a V-shaped convex portion, a trapezoidal groove, and a trapezoidal convex portion). Only one reflection surface may be provided in one optical path conversion unit, or two or more reflection surfaces may be provided. The reflective surface may be formed of any material as long as it can reflect light. For example, the reflective surface is preferably formed of a material having high reflectivity such as metal. Copper, rhodium, nickel and the like are preferable. These may use only 1 type and may use 2 or more types together.

  The method for forming the optical path changing portion is not particularly limited. For example, before forming the clad portion, a metal wire is supplied into a capillary provided in the wire bonding apparatus, the tip end portion of the metal wire is made into a lump, and then pressed. A jig can be pressed and molded to form an optical path changing portion having a predetermined shape. Furthermore, after forming the clad part, a notch is provided in the clad part, a layer made of metal or the like is formed in the notch, or a reflective layer is provided in the notch and then filled with some material. Or the like.

The type of the conductor portion is not particularly limited, and examples thereof include normal wiring, through-hole conductors, via conductors, wiring patterns that function as resistors, wiring patterns that function as inductors, wiring patterns that function as capacitors, lands, and the like. There are no particular restrictions on the location of these conductor portions, but they can be placed in the clad, on the surface of the clad portion, in the substrate portion described later, and the like. Furthermore, the material which comprises a conductor part is not specifically limited, For example, gold | metal | money, silver, copper, platinum, nickel, chromium, titanium, aluminum, tungsten, molybdenum etc. can be used. These may use only 1 type and may use 2 or more types together.
The method for forming the conductor part is not particularly limited. For example, sputtering, ion plating, vapor deposition (including CVD and PVD), vapor deposition and plating, and patterning such as photolithography. Can be obtained in combination with the law.

The material which comprises a board | substrate is not specifically limited, An organic type material, an inorganic type material, the composite material using both of these, etc. are mentioned.
The organic material is not particularly limited. For example, epoxy resin, BT (bismaleimide / triazine) resin, polyimide resin, phenol resin, xylene resin, thermosetting PPE (polyphenylene ether) resin, LCP ( Liquid crystal polymer), BCB (benzocyclobutene), polynorbornene and the like. These organic materials may be used alone or in combination of two or more. In addition, various rubbers and the like can be used in combination for the purpose of, for example, improving the strength of the substrate portion.
Further, when an organic material is used, glass cloth, glass nonwoven fabric, resin (polyamide, etc.) cloth, resin (polyamide, etc.) nonwoven fabric, resin (polyamide, etc.) film, PTFE (polytetra A fluororesin-based core material and a metal foil having a three-dimensional network structure formed of (fluoroethylene) or the like may be used.

  The inorganic material is not particularly limited. For example, alumina, quartz, titania, zirconia, garnite, titanate (magnesium titanate, calcium titanate, strontium titanate, barium titanate etc.), mullite, cordierite, Examples thereof include ceramic materials such as stellite, wollastonite, anorthite, enstatite, diopsite, akermanite, gelenite, and spinel. Furthermore, crystalline or non-crystalline glass-based materials can be mentioned. Examples of the component constituting the glass material include Si, Al, Na, K, Mg, Ca, B, Pb, and Zn. Specific examples include aluminosilicate glass and aluminoborosilicate glass. These ceramic materials and glass materials may be used alone or in combination. When used in combination, a ceramic material can be contained in the glass material as a filler. These inorganic materials may be used alone or in combination of two or more.

  The coating method of the uncured material is not particularly limited, and for example, it can be directly formed at the formation position using various printing methods such as a doctor blade method, a spray method, a curtain coating method, and a roll coating method.

  When pressure bonding an uncured film, the support may be peeled off after pressure bonding, and the film body may be laminated, or the film body that has been peeled off in advance is laminated on the lower clad portion. Also good. Especially, after arrange | positioning from a viewpoint of operativity, it is preferable to peel a support body and to laminate a film body. The “support” is not particularly limited as long as it can be peeled off from the film body. For example, polyester such as polyethylene terephthalate (PET), polyethylene, polypropylene, polyamide, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polycarbonate, polystyrene, polyacrylonitrile copolymer, ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol Examples thereof include a resin film such as a copolymer and a resin sheet. Moreover, the shape of a support body is not specifically limited, It can be set as a predetermined shape according to a use.

  The method for producing a device with an optical waveguide structure according to the present invention can be widely used in the fields of optical communication, electrical and electronic fields, and the like. For example, it can be used as an optical waveguide, an optical branching coupler, an optical multiplexer / demultiplexer, an optical isolator, an optical fiber amplifier, a wiring board, an IC package, and the like.

It is typical sectional drawing of an example of the device with an optical waveguide structure of this invention. It is explanatory drawing which shows the AA cross section in FIG. 1 typically. It is explanatory drawing which shows the BB cross section in FIG. 4 typically. It is typical sectional drawing of the other example of the device with an optical waveguide structure of this invention. It is explanatory drawing explaining an example of the manufacturing method of a device with an optical waveguide structure. It is explanatory drawing explaining an example of the manufacturing method of a device with an optical waveguide structure, Comprising: It is explanatory drawing explaining the process following FIG. It is explanatory drawing explaining the other example of the manufacturing method of the device with an optical waveguide structure. It is explanatory drawing explaining the other example of the manufacturing method of a device with an optical waveguide structure, Comprising: It is explanatory drawing explaining the process following FIG. It is explanatory drawing explaining an example of the manufacturing method of this device with an optical waveguide structure. It is explanatory drawing explaining the device with this optical waveguide structure of a prior art example. It is explanatory drawing explaining the device with this optical waveguide structure of another prior art example.

Explanation of symbols

100, 200; device with optical waveguide structure, 1; core portion, 10; uncured film for forming core portion, 11: uncured core portion, 20; uncured film for lower clad portion (uncured lower clad portion), 21 ; Lower clad part, 22; upper clad part, 23; uncured film for upper clad part (uncured upper clad part), 3; substrate, 41, 42; optical path changing part, 411, 421; pad for optical path changing part, 51; Support, 52; Surface protective film, 61; Light emitting element, 62; Light receiving element, 7; Photomask, 81 and 82; Conductor part, 91 and 92; Positioning reference, 93; Wiring (conductor part)

Claims (4)

In a method of manufacturing a device with an optical waveguide structure comprising an optical waveguide structure on a substrate, the optical waveguide structure having a core portion through which light propagates, and an upper cladding portion and a lower cladding portion and surrounding the core portion,
An uncured lower clad part forming step of crimping an uncured film for the lower clad part on the substrate;
A lower clad part forming step of obtaining the lower clad part by curing the uncured film for the lower clad part;
A core part forming step for forming the core part;
An upper clad portion forming step for forming the upper clad portion;
A method for manufacturing a device with an optical waveguide structure, comprising:   The method for manufacturing a device with an optical waveguide structure according to claim 1, wherein the substrate is a wiring substrate.   3. The method for manufacturing a device with an optical waveguide structure according to claim 1, wherein other components are mounted on the substrate. The method for manufacturing a device with an optical waveguide structure according to claim 1, wherein the substrate includes a cavity portion.

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