WO2008062836A1

WO2008062836A1 - Optical waveguide module and method for manufacturing the same

Info

Publication number: WO2008062836A1
Application number: PCT/JP2007/072569
Authority: WO
Inventors: Masatoshi Hayashi; Toshio Ikugata
Original assignee: Nikon Corporation
Priority date: 2006-11-22
Filing date: 2007-11-21
Publication date: 2008-05-29
Also published as: JPWO2008062836A1; JP5182097B2

Abstract

An optical waveguide module (100) is provided with a substrate (1), an optical waveguide formed on one surface (1b) of the substrate (1), and a plurality of lenses (3) formed on the other surface (1a) of the substrate (1). The optical waveguide (2) has inclined sections (2b) at the both end sections, and the lenses (3) are formed at the positions facing the inclined sections (2b) by having the substrate (1) in between. The optical waveguide (2) and the lenses (3) are made of a cured resin material, and the refraction index of the substrate (1) is lower than the refraction index of the optical waveguide (2) and any of the refraction indexes of the lenses (3).

Description

Specification

Optical waveguide module and manufacturing method thereof

Technical field

The present invention relates to an optical waveguide module that connects boards, chips, and the like, and a method for manufacturing the same.

Background art

Recently, with the increase in speed and density of signal wiring in integrated circuits, optical wiring technology using optical waveguides has attracted attention. Under such circumstances, optical waveguides using resin materials that are easy to manufacture and inexpensive are attracting attention.

[0003] Various methods have been proposed as a method for manufacturing a resin optical waveguide. For example, Patent Document 1 proposes an optical waveguide module in which both the clad layer and the core layer are made of resin, and a lens is formed on one surface of the mounting substrate and a waveguide is formed on the other surface.

[0004] In Patent Document 2, an attempt is made to improve the strength of the optical waveguide module by using a resin material for both the core layer and the cladding layer and providing a reinforcing structure in the cladding layer. JP 2005-181645

Patent Document 2: JP 2005-338125 A

Disclosure of the invention

Problems to be solved by the invention

However, in the manufacturing method in which the lens and the optical waveguide of Patent Document 1 are integrated, since both the cladding layer and the core layer are made of resin, they are easily deformed by heat and external force.

Furthermore, since the lens is constructed integrally with the cladding layer, a resin with a high refractive index cannot be used for the lens, and it is necessary to increase the thickness of the lens in order to obtain the desired refractive power. There is a problem that the degree is low. Another problem is that the optical waveguide module expands due to the hygroscopic nature of the resin, and the optical axis gradually shifts. Furthermore, in the process of molding the resin into the desired shape, there is a problem that when the resin molded product is peeled from the mold, it is easily deformed and the product yield is poor. [0006] In addition, the method of Patent Document 2 has a problem in that since the module structure is complicated, the manufacturing process is also complicated, and as a result, the production cost increases.

[0007] Meanwhile, it has not been carried out so far that an input / output lens and an optical waveguide are integrated into a single module by press molding. When an optical waveguide is manufactured by press molding, not only the ultraviolet fountain cured resin is filled into the optical waveguide cavity during pressing, but also a resin layer is formed outside the cavity due to excess resin. Is concerned. This resin layer may cause light leakage and increase in optical loss when actually used as an optical waveguide. Further, when forming the optical waveguide and the lens provided opposite to each other, the alignment between the inclined portion, which is the light entrance / exit portion of the optical waveguide, and the optical axis of the lens is generated, which causes optical loss. obtain.

[0008] The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical waveguide module having a high degree of freedom in design and sufficiently excellent light coupling efficiency. Another object of the present invention is to provide a method of manufacturing an optical waveguide module that can form a lens and an optical waveguide with sufficient positional accuracy with high V and productivity.

Means for solving the problem

In order to achieve the above object, the present invention includes a substrate, an optical waveguide formed on one surface side of the substrate, and a plurality of lenses formed on the other surface side of the substrate. In the optical waveguide module, the optical waveguide has inclined portions at both ends thereof, and the plurality of lenses are respectively formed at positions facing the inclined portion with the substrate interposed therebetween. Provided is an optical waveguide module in which each of the plurality of lenses is made of a cured resin, and the refractive index of the substrate is V of the optical waveguide and the plurality of lenses, and is lower than the refractive index of displacement. To do.

[0010] In the optical waveguide module of the present invention, the substrate is preferably glass. In addition, it is more preferable that the glass is quartz glass.

[0011] In the optical waveguide module of the present invention, it is preferable that the optical waveguide is formed on an optical waveguide side base layer formed on one surface of the substrate.

[0012] Further, in the optical waveguide module of the present invention, it is preferable that the thickness of the optical waveguide side base layer is 5.1 m or less! /. [0013] In the optical waveguide module of the present invention, it is preferable that the plurality of lenses are respectively formed on a lens-side base layer formed on the other surface of the substrate.

[0014] Further, in the optical waveguide module of the present invention, it is preferable that the lens is a lens having a ridge formed on a peripheral edge! /.

[0015] Further, the optical waveguide module of the present invention preferably includes a plurality of the optical waveguides on one surface side of the substrate.

[0016] In the above optical waveguide module, it is preferable that V and the plurality of optical waveguides are simultaneously formed on one surface side of the substrate. The plurality of lenses are preferably formed on the other surface side of the substrate at the same time. The lens is preferably a coupling lens of the optical waveguide and an external optical system.

[0017] In the present invention, the first resin precursor of the first mold having a dent corresponding to the shape of the optical waveguide is filled with the first resin precursor in the dent. Is attached to the substrate and cured to form an optical waveguide forming step for forming the optical waveguide having inclined portions at both ends on one surface side of the substrate, and a second portion having a recess corresponding to the shape of the lens. In the state where the second resin precursor is filled with the second resin precursor, the second resin precursor is brought into close contact with the substrate and cured, so that the other side of the substrate is sandwiched between the substrates. A lens forming step for forming the lens on the surface side of the optical waveguide, before curing at least one of the first resin precursor and the second resin precursor. The inclined part and the lens are arranged to face each other , To provide a manufacturing method of the optical waveguide module, characterized in that positioning at least one of the first mold and the second mold.

[0018] In the method of manufacturing an optical waveguide module of the present invention, at least one of the first mold and the second mold has a alignment mark, and the alignment mark is used as a reference. It is preferable to position at least one of the first mold and the second mold.

[0019] In the optical waveguide forming step of the present invention, a thickness is provided between the optical waveguide and the substrate. It is preferable to adjust the distance between the first mold and the substrate so that an optical waveguide side base layer of 5 m or less is formed.

[0020] Further, in the method for manufacturing an optical waveguide module of the present invention, it is preferable that the second mold has a recess corresponding to a lens having a ridge formed on the periphery.

[0021] Further, in the method for manufacturing an optical waveguide module of the present invention, it is preferable that the ridge is formed continuously on the periphery of the lens.

The invention's effect

In the optical waveguide module of the present invention, since the optical waveguide and the lens are formed separately from the substrate, deformation due to heat is small and the positional accuracy is sufficiently excellent. For this reason, the light coupling efficiency is sufficiently excellent. Further, since the refractive index of the substrate is lower than the refractive indexes of the optical waveguide and the lens provided on both surfaces of the substrate, it is possible to reduce the thickness of the lens without impairing the function of the optical waveguide. In addition, since the optical waveguide and the lens can be formed separately from the substrate, it is possible to configure the lens using a resin having a higher refractive index, the thickness of the lens can be made thinner, and design flexibility is sufficient. Very expensive.

Furthermore, since both the optical waveguide and the lens are formed by press molding, a low-cost and high-precision optical waveguide module can be efficiently manufactured.

Brief Description of Drawings

FIG. 1 is a schematic cross-sectional view schematically showing a cross-sectional structure of an optical waveguide module according to a preferred embodiment of the present invention.

FIG. 2 is a process cross-sectional view schematically showing a lens mold manufacturing method using a photoresist.

FIG. 3 is a process cross-sectional view schematically showing an optical waveguide type manufacturing method using a photoresist.

FIG. 4 is a process cross-sectional view schematically showing an optical waveguide forming step for forming an optical waveguide by press molding using an optical waveguide mold.

FIG. 5 is a diagram schematically showing a lens forming step of forming a lens using a lens mold on a substrate.

Explanation of symbols

[0025] 1 ··· Substrate, 2 ··· Waveguide, 2b ... Inclined portion, 6 ··· Optical waveguide side base layer, 3 ··· Lens, 3a--- Lens body, 3b… 鍔, 5 ··· Reference protrusion, 7 ··· Lens side base layer, 21, 31 ··· Photoresist layer, 22, 32… Substrate, 25, 36 ··· Transparent substrate ( Push plate), 26, 35, 40 ··· Photo-curing resin (ultraviolet spring hard 匕 type moon), 24, 27… Protrusion ^ 23, 33 ··· Graceke Nore mask, 34, 200… Resist type master, 37 ··· Optical waveguide type, 45. CCD camera.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a schematic cross-sectional view schematically showing a cross-sectional structure of an optical waveguide module according to a preferred embodiment of the present invention. The optical waveguide module 100 includes a mounting substrate 1 made of quartz glass, an optical waveguide member 20 formed on one surface lb of the mounting substrate 1, and a lens member 30 formed on the other surface la of the mounting substrate 1. With.

The optical waveguide member 20 includes an optical waveguide 2 and an optical waveguide side base layer 6, and the optical waveguide side base layer 6 is provided between the mounting substrate 1 and the optical waveguide 2 with a predetermined thickness. .

The lens member 30 includes a lens 3, a lens side base layer 7, and a reference protrusion 5, and the lens side base layer 7 is interposed between the mounting substrate 1, the lens 3, and the reference protrusion 5. It is installed with a predetermined thickness. The pair of reference protrusions 5 are separated from the lens 3 at a predetermined interval, and are provided on the lens-side base layer 7 like the lens 3 so as to sandwich the lens 3. The reference protrusion 5 serves as a reference for molding the optical waveguide 2 formed on the surface lb opposite to the lens side of the mounting substrate 1 and has a function of protecting the lens 3.

In FIG. 1, only one lens is shown for convenience. Actually, the optical waveguide module 100 is the same as the lens 3 on the one side la side (the right side in FIG. 1) of the mounting substrate 1. With another lens. Similarly, the optical waveguide 2 is provided with another inclined portion at the end opposite to the inclined portion 2b shown in the figure. Then, the other lens V, not shown, is provided so as to face the other inclined portion. One inclined portion of the optical waveguide 2 functions as a light incident portion, and the other inclined portion functions as a light emitting portion.

[0030] The lens 3 functions as a lens for entering or emitting an optical signal. The lens 3 includes a convex lens body 3a having a curved surface for changing the light path, and a flange (pedestal) 3b provided continuously around the periphery of the lens body 3a. The flange 3b is formed by a ring-shaped step portion in the lens mold in the lens mold fabrication described later. This step portion is formed between the lens mold and the removal portion when foaming occurs when the photoresist is cured. Functions as a buffer area. Therefore, the lens 3 is provided with the flange 3b at the periphery, whereby the light coupling efficiency can be further improved.

The optical waveguide 2 includes a main body 2a that transmits an optical signal, and an inclined portion 2b that changes the traveling direction of light when an optical signal is input to and output from the optical waveguide 2. The inclined portion 2b is provided to face the lens 3 so that the optical axis position of the lens 3 corresponds to the inclined portion 2b of the optical waveguide 2. The inclined portion 2b is formed by a surface lb of the mounting substrate 1, the optical waveguide 2 and the optical waveguide in a cross section parallel to the direction of the optical axis connecting the lens 3 and the inclined portion 2b shown in FIG. It is tilted so that the angle formed with the contact surface with the side base layer 6 is 45 degrees.

[0032] The cross section in the direction perpendicular to the light transmission direction of the main body 2a, which is the optical transmission line portion of the optical waveguide 2, is usually rectangular with several to several tens of sides. Of course, the required length of transmission line is required. The length varies depending on the application. Usually, even a short one needs several millimeters or more. If there is an abrupt shape change or a step in the meantime, the light is irregularly reflected and the transmission characteristics tend to deteriorate. In principle, since total reflection of light is used, each surface of the light transmission path of the main body 2a must be flat.

[0033] As the mounting substrate 1, general glass may be used in addition to quartz glass. By using mounting glass 1 made of ordinary glass or quartz glass, the overall dimensions of the optical waveguide module 100 are reduced by suppressing deformation due to heat and external force compared to an optical waveguide module that is made entirely of resin and integrated with a lens. Accuracy can be improved. Therefore, a high-quality optical waveguide can be obtained with stable accuracy. For example, if the thickness of the mounting substrate 1 is 0.5 mm or more, it is possible to sufficiently suppress damage and deformation during the production, particularly when the lens or optical waveguide is released from the lens mold or optical waveguide mold. As a result, the yield is improved, and high productivity can be secured.

Here, the light incident / exit path in the optical waveguide module 100 will be described. The light incident from the lens 3 travels to the inclined portion 2b of the optical waveguide 2 formed at a position facing the lens 3 with the mounting substrate 1 in between. The traveling direction of light is changed by 90 degrees by being totally reflected by the inclined portion 2b, and is switched to the longitudinal direction of the optical waveguide 2. The mounting substrate 1 has a lower refractive index than the optical waveguide that is the core layer, and functions as a cladding layer in the optical waveguide module 100. When the direction of travel is switched to the longitudinal direction The incident light reaches the other slope not shown, and the traveling direction is changed 90 degrees again. Thereafter, the light is emitted from another lens provided facing the inclined portion with the mounting substrate 1 interposed therebetween.

In the present embodiment, a quartz glass substrate having a low refractive index is used as the mounting substrate 1. For this reason, the lens 3 can be formed of a material having a high refractive index. For this reason, the lens can be thinned, and the degree of freedom in designing the optical waveguide module can be improved.

[0036] The optical waveguide 2 and the optical waveguide base layer formed on the surface la lb of the mounting substrate 1, respectively.

The optical waveguide member 20 having 6 and the lens member 30 having the lens 3, the reference protrusion 5 and the lens base layer 7 are both formed by a pressure molding method using an ultraviolet curable resin. The optical waveguide member 20 and the lens member 30 are preferably integrally formed by press molding using a mold from the viewpoint of achieving both high dimensional accuracy and strength at a high level.

Next, a method for manufacturing the optical waveguide module of the present invention will be described. In this embodiment, since the optical waveguide module mounted on the substrate is formed by press molding, it is necessary to prepare a lens type and an optical waveguide type in advance. Therefore, a manufacturing method of a lens type and an optical waveguide type by an exposure process method using a gray scale mask (GSM) will be described.

[0038] (Lens mold production)

The lens mold to be produced is used to form a lens for introducing or deriving light from the optical waveguide and a reference protrusion higher than the lens height.

FIG. 2 is a process cross-sectional view schematically showing a lens mold manufacturing method using a photoresist. In this embodiment, first, a resist type master having a lens shape is formed by the GSM exposure method, and then a lens type (submaster) is formed using the resist type master. Details of the lens mold manufacturing method will be described below.

[0040] <Coating process>

First, a substrate is prepared for forming a resist master. As the substrate, quartz glass, Si wafer or the like having good flatness can be used. Especially eztin finally shape In the case of engraving with a substrate, a substrate suitable for the etching process is prepared. In this embodiment, the force S using quartz glass and the material of the substrate are not particularly limited.

Next, as shown in FIG. 2 (a), a photoresist layer 21 is formed on the surface of the quartz glass substrate 22, and spin coating or spraying is performed to a thickness corresponding to the thickness of the lens to be finally formed. Apply by applying. Although not shown here, in order to ensure adhesion between the photoresist layer 21 and the substrate 22, an anchor coat may be applied to the substrate 22 as a base before applying the photoresist layer 21. After applying the photoresist on the surface of the substrate 22, it is preferable to perform pre-bake treatment to remove unnecessary gas. By performing this pre-bake treatment, the sensitivity of the photoresist is stabilized, and foaming due to overpower exposure can be suppressed.

[0042] <Exposure and development process>

Next, as shown in FIG. 2 (b), the applied photoresist layer is exposed using a gray scale mask 23 previously prepared according to the lens shape and developed to form a resist master 200. To do.

Before forming the resist type master 200, a plurality of masks are prepared as necessary. In the present embodiment, three masks are used: the gray scale mask (GSM) 23, the protrusion formation mask, and the alignment mark formation mask. Fig. 2 (b) shows the case where the gray scale mask 23 is used!

[0044] For the production of the gray scale mask (GSM) 23! /, First of all, it corresponds to the desired lens shape based on the sensitivity curve of the resist used, the influence of development, data such as the etching rate, etc. It is necessary to determine the aperture ratio to be performed. Then, the light shielding point group or the aperture hole group is arranged so as to match the aperture ratio. The mask is usually made with an electron beam lithography system using a Cr film, and unnecessary parts are removed by the lift-off method or wet etching method.

Yes

[0045] Note that GSM may be manufactured by a direct electron beam lithography apparatus. In addition, as a 5 × reduction exposure mask with a stepper, a 5 × size mask may be produced with an electron beam lithography apparatus. According to the latter, further fine holes can be realized with high accuracy.

In the present embodiment, a positive exposure mask is used as the gray scale mask 23. By exposing the thick photoresist layer 21 through the gray scale mask 23, an arbitrary exposure distribution is given to the photoresist layer 21. By developing after exposure, the lens-side resist master 200 can be produced. According to this method, the grayscale mask 23 can be designed by obtaining the exposure dose according to the position from the basic data of the photoresist layer and the desired lens shape. According to such a method, a large number of lenses can be accurately produced within the same plane, and any aspherical shape can be produced with high accuracy and without variation.

[0047] The gray scale mask 23 is preferably a pattern having a numerical aperture smaller than the resolution of the exposure apparatus used. This makes it possible to form a smooth exposure distribution. In fact, a smoother curved surface can be realized by defocusing during exposure.

[0048] A binarization mask is used for exposure of the lens portion other than the convex portion. As the shape of the lens mold, the resist corresponding to the area where nothing is formed (the area where the resin cured product does not remain) is removed. Here too, the force S produced by electron beam lithography, usually a highly accurate shape like a gray scale mask, is not required.

A mask for forming alignment marks can also be produced by electron beam drawing. The alignment mark can be convex or concave. Therefore, a mask for forming alignment marks capable of forming the shape is produced.

[0050] Using the above-described three masks, the photoresist layer 21 applied on the substrate 22 is exposed. The exposure can be performed using a normal ultraviolet irradiation device.

[0051] Here, a step 24b for forming a lens ridge is provided at the edge of the protrusion 24 corresponding to the lens of the lens-side resist master 200. The step 24b is provided in order to prevent the lens shape from being deformed by foaming during resin hardening. The protrusion 27 of the resist master 200 is a protrusion for forming a reference protrusion 3 formed in a later process described later.

In the present embodiment, after the exposure using the gray scale mask 23, the projection forming mask

An area other than the convex portion is exposed using (binarization mask). After that, alignment Exposure is performed using a mask for forming a mask. Each exposure is performed sequentially using a projection reduction exposure apparatus.

[0053] In particular, in the exposure using the projection forming mask, all the resist for the flat portion having no convex portion and no lens portion is removed. This exposure tends to be overpowered because it tries to fully expose the thick photoresist layer. In this way, irradiation with high-energy light with excessive power tends to generate gas (foaming) and cause a foaming phenomenon that destroys the resist shape. In order to sufficiently suppress this foaming phenomenon, as shown in FIG. 2 (b), it is preferable that the protrusion 24 is provided with a step 24b by performing a process of leaving a one-step resist around it. As a result, it is possible to sufficiently prevent deformation of the lens-shaped protrusion 24 when the resin is cured.

[0054] In order to form the step 24b, the size of the projection 24 corresponding to the lens shape is adjusted to be larger than the diameter of the lens body by adjusting the transmittance of the gray scale mask. In adjusting the transmittance, it is preferable that the thickness of the step 24b is set to be different depending on the SAG amount (lens center thickness). For example, if the SAG amount is 30 m, it is preferable to adjust the transmittance so that the thickness of the step 24b is 10 to 25 m. By doing so, even if foaming occurs in the exposure for completely removing the flat portion, the stepped portion 24b acts as a buffer region, and the deformation of the portion corresponding to the lens body of the protruding portion 24 is sufficiently performed. Can be suppressed. Note that exposure using a grayscale mask to form the lens body using GSM is usually done with over-exposure, so there is almost no foaming phenomenon.

[0055] After the exposure is completed, development is performed by a normal method. By allowing the developer to flow evenly on the exposed surface of the substrate, many portions that are strongly irradiated with light are removed, and few portions that are weakly irradiated with light are removed. As a result, as shown in FIG. 2 (b), a pattern of the lens array on the microphone opening (lens side resist type master 200) is obtained.

The lens-side resist master 200 is formed with shapes such as a lens, a reference projection, and alignment marks that are finally required. In order to smoothly perform the mold release in the lens forming step described later, it is preferable to apply a known mold release agent and / or to form a Ni light-shielding film on the surface of the completed resist master 200. (Shown Absent).

[0057] Although not performed in the present embodiment, a desired pattern can be engraved in a stable material such as a quartz glass substrate by etching. Usually, it is transferred to a substrate such as quartz glass by RIE (Reactive Ion Etching) or ICP (Inductively Coupled Plasma). This etching rate is also easy to change! / Be careful when making precise shapes.

[0058] <Press molding process>

FIG. 2 (c) schematically shows a press molding process for forming a lens mold. Based on the resist mold master 200 produced as described above, a mold is taken with the ultraviolet curable resin 26 to form a lens mold 29 (submaster). Specifically, the UV curable resin 26 is dropped on the resist master 200 with the Ni light-shielding film formed on the surface, and the transparent substrate (pressing plate) 25 is pressed against the UV-cured pattern surface of the microlens array. Extend mold resin 26. As a result, the UV curable resin 26 is spread evenly and thinly on the pattern surface of the resist master 200. Then, press molding is performed in which the ultraviolet curable resin is closely attached to the pattern surface of the resist master 200 and the transparent substrate 25. At this time, pressure is applied between the transparent substrate 25 and the substrate 22 provided with the resist master 200, and the UV curable resin adhesive 26 is sufficiently adhered to the pattern surface of the resist master 200 and the transparent substrate 25. Preferably.

[0059] <Resin curing process>

Fig. 2 (d) schematically shows the resin curing process. After performing the pressing process as shown in FIG. 2 (c), in the resin curing step, the ultraviolet curable resin 26 is cured by irradiating ultraviolet rays.

Note that if a Ni light-shielding film is previously formed on the surface of the resist mold master 200, foaming of the cured resin constituting the resist mold master 200 can be sufficiently prevented. In particular, it is effective to form a Ni light-shielding film when the center thickness of the projection 24 for forming the lens is thick. The reason is as follows. That is, when the center thickness of the lens-forming projection 24 is thick and the depth of the pattern shape is deep, the UV curable resin layer to be applied increases with the depth, and the UV curable resin is applied in the resin curing process. To cure Therefore, it is necessary to irradiate with high energy ultraviolet rays (uv light). As a result, the solvent or the like which has been latent in the cured resin forming the resist type master 200 is vaporized, and there is a tendency that bubble-like defects are generated on the surface of the resist type master 200. Therefore, by forming a Ni light-shielding film on the surface of the resist master 200, it is possible to shield the UV energy when UV-curing the UV-curable resin from being directly transmitted to the resist master 200 side. The light-shielding film is not limited to the Ni light-shielding film, but a normal Ni light-shielding film is preferably used because it has both light-shielding properties and releasability.

[0061] If the depth of the pattern shape that increases the center thickness of the lens is not deep, the amount of foam irradiation on the surface of the resist master 200 can be adjusted by adjusting the amount of ultraviolet irradiation energy without using the Ni light-shielding film. Defects can be sufficiently suppressed. In this way, the presence or absence of the light shielding film, the film thickness, the adjustment of the irradiation power amount of the UV light, etc. can be set according to the pattern shape.

[0062] <Mold release process>

Figure 2 (e) schematically shows the mold release process. The lens mold 29 is completed by releasing the cured resin from the resist mold master 200 by the resin curing process.

[0063] The transfer pattern surface of the ultraviolet curable resin of the lens mold 29 is subjected to a release treatment by a normal method. Examples of mold release treatment methods include Ni thin film formation and fluorine mold release agents. In the Ni thin film formation method, a Ni thin film with a thickness of about several tens of angstroms is formed on the surface of the lens mold 29 by a method such as sputtering. In addition, as the fluorine-based mold release agent, an ordinary commercially available one can be used, and a fluorocarbon solvent-based one that does not leave a stain or the like is preferably used.

[0064] If the Ni film has a thickness of several tens of angstroms, ultraviolet rays can be sufficiently transmitted. Therefore, in the lens mold forming step described later, the UV light is irradiated through the lens mold.

In this embodiment, as a representative example of a method for manufacturing a lens mold, the force described for the manufacturing method by an exposure method using a gray scale mask is used. For example, a lens mold is manufactured by an optical modeling method. Moyore.

[0066] In addition, the foaming phenomenon occurs in two steps, that is, an exposure process when forming a resist mold master, and a process of forming a lens mold by transferring an ultraviolet curable resin from the resist mold master. It may occur in the resin curing process with UV light. For this reason, The mold 29 has a recess 29a that forms a convex portion of the lens and a ring-shaped recess 29b. The recess 29b has a larger diameter than the recess 29a in a cross section parallel to the contact surface between the transparent substrate 25 and the resist mold 29. The ring-shaped recess 29b is formed corresponding to the step 24b of the resist mold master 200.

[0067] (Optical waveguide type fabrication)

FIG. 3 is a process cross-sectional view schematically showing an optical waveguide type fabrication method using a photoresist. In this embodiment, an optical waveguide-shaped resist master is formed, and then the optical waveguide mold is formed using the resist master. In this embodiment, exposure is performed using two masks, GSM and a binarization mask. Note that GSM was used during lens mold fabrication. However, if the target shape is an inclined plane, the force S for producing the GSM for forming the inclined portion can be reduced by the same design method.

[0068] Since the selection of the substrate, the production of the GSM and the binarization mask, and the respective steps can be performed in the same manner as the above-described lens mold, redundant description is omitted in some cases.

[0069] <Coating process>

First, a substrate is prepared to form an optical waveguide-shaped resist master (FIG. 3 (a)). As the substrate 32, the same substrate as that used for the lens mold fabrication can be used.

Next, as shown in FIG. 3 (a), a coating process for coating a thick film photoresist 31 on one surface of the substrate 32 is performed. This coating process can be performed in the same manner as the lens mold manufacturing coating process.

Next, as shown in FIG. 3 (b), only the inclined portion 34 b is exposed using the gray scale mask 33. In FIG. 3 (b), the central portion 33b of the gray scale mask 33 is a gray scale. The end portion 33a of the gray scale mask 33 corresponding to the portion that exposes the inclined portion 34b has a lower light transmittance as it is closer to the central portion 33b. This inclined portion 34b is used to form an optical path switching mirror (inclined portion). The portion corresponding to the formation of the transmission portion of the optical waveguide needs to be left in a convex shape, and is not exposed here.

Subsequently, an unnecessary flat portion is exposed, and binarized mask exposure is performed to leave a protruding portion (waveguide). In particular, because the waveguide cross section is close to a rectangle instead of a trapezoid, Exposure. Thereby, the ultraviolet curable resin is cured.

Thereafter, exposure for forming alignment marks is performed as necessary, and development processing is performed. The “exposure” development step can be performed in the same manner as in the formation of the lens mold. As a result, an optical waveguide resist master 34 having an inclined portion 34b is obtained.

It is to be noted that, also in the optical waveguide resist master 34, it is preferable to form a Ni light-shielding film on the surface in the same manner as the lens resist master 200.

[0075] <Press molding process>

Next, a press molding process is performed in the same manner as the lens mold formation. Fig. 3 (c) schematically shows the press molding process for forming the optical waveguide mold. Specifically, an ultraviolet curable resin is dropped onto the pattern surface of the resist master 34 formed with a Ni light-shielding film, and the resin is spread by a transparent substrate (press plate) 36. As a result, the ultraviolet curable resin 35 is spread evenly and thinly on the pattern surface of the resist master 34 to transfer the shape of the resist master 34. Then, press molding is performed in which the ultraviolet curable resin is brought into close contact with the pattern surface of the resist master 34 and the transparent substrate 36. At this time, pressure is applied between the transparent substrate 36 and the substrate 32 having the resist master 34 to bring the UV curable resin adhesion 26 into close contact with the pattern surface of the resist master 34 and the transparent substrate 36. Is preferred.

Thereafter, a resin curing process is performed in the same manner as the lens mold formation, and the optical waveguide mold 37 is completed on the transparent substrate 36 by a mold release process for releasing from the optical waveguide mold 34 as shown in FIG. As in the case of the lens mold 29, the transfer pattern surface of the ultraviolet curable resin of the optical waveguide mold 37 is preferably subjected to a mold release process by a normal method.

[0077] The manufacturing method of the lens type and the waveguide type has been described above. The lens mold and the optical waveguide mold can improve the productivity of an optical waveguide module, which will be described later, by producing a plurality of molds on one substrate.

[0078] (Manufacture of optical waveguide module)

Next, a method for manufacturing the optical waveguide module will be described. An optical waveguide module uses an ultraviolet curable resin on one side of a mounting board to form an optical waveguide, and an ultraviolet spring curable resin on the other side opposite to the one side of the mounting board. Forming a lens Can be obtained.

[0079] (1) Optical waveguide formation step

In the optical waveguide forming step, an optical waveguide is formed on one surface of the mounting substrate by press molding using a photo-curing resin.

FIG. 4 is a process cross-sectional view schematically showing an optical waveguide forming step for forming an optical waveguide by press molding using an optical waveguide mold. First, one surface Q of the substrate 1 is subjected to a silane coupling process using a spin coater. In this embodiment, quartz glass is used as the substrate 1. A commercially available silane coupling solution can be used. Specifically, a mixed solution of KBM503 (manufactured by Shin-Etsu Chemical Co., Ltd., trade name), acidic water with acetic acid and ethanol can be used.

Next, as shown in FIG. 4 (a), a predetermined amount of ultraviolet curable resin 40 is applied dropwise so as to cover the waveguide pattern of the optical waveguide mold 37.

In this embodiment, the ultraviolet fountain curable resin for an optical waveguide has a curing shrinkage ratio of 6 to 7%, a viscosity of 760 mPa ′ S (25 ° C.), and a refractive index after curing of 1.5536. The acrylic photo-curing resin is used. In addition to the acrylic photocurable resin, a normal photocurable resin (ultraviolet curable resin) can be used.

[0083] It is preferable to perform defoaming by placing the optical waveguide type 37 coated with the ultraviolet curable resin by dropping into a vacuum defoaming machine. The conditions of the defoamer can be, for example, a heater heating of 50 ° C. and a decompression condition of 75 mmHg. After defoaming, for example, press the UV spring curable resin 40 in the direction of the optical waveguide type 37 (arrow direction in Fig. 4 (a)) on the Q surface of the substrate 1 on the plate at 80 ° C, and finally Thus, the thickness of the base layer 6 on the optical waveguide side obtained can be made more uniform.

FIG. 4B is a schematic cross-sectional view showing a step of irradiating the resin having a predetermined shape with ultraviolet rays (UV light). With the UV curable resin 40 disposed between the substrate 1 and the optical waveguide mold 37 being in close contact with the substrate 1 and the optical waveguide mold 37, the UV curable resin 40 is irradiated with UV light from outside the mold. The UV curable resin 40 is cured. Thereby, an optical waveguide can be formed on one surface side of the substrate 1. The UV curable resin 40 is cured while pressure is applied between the substrate 1 and the optical waveguide mold 37 so as to sandwich the UV curable resin 40. Is preferred.

[0085] Irradiation conditions of ultraviolet rays (UV light) can be set as follows, for example. First, provisional irradiation is performed by moving a 100mm length at a speed of 3 reciprocations / min using an lm m slit. After that, the slit is removed, and main irradiation is performed to expose the entire surface of the UV curable resin 40 in a lump. For example, the integrated irradiation amount of the temporary irradiation and the main irradiation can be set to lOOOOmj / cm ² . As described above, by performing the provisional irradiation and the main irradiation, a rapid curing reaction can be suppressed, and transfer defects due to curing shrinkage of the ultraviolet ray curable resin can be more reliably prevented.

[0086] As described above, after the ultraviolet curable resin 40 is cured to form the optical waveguide 2 and the optical waveguide side base layer 6, as shown in FIG. An optical waveguide member 20 comprising an optical waveguide side base layer 6 and an optical waveguide 2 formed on the optical waveguide side base layer 6 by separating the substrate 1 on which the waveguide 2 is formed from the optical waveguide type 37 (release). A substrate 1 on which is formed is obtained.

The optical waveguide 2 is fixed to the substrate 1 via the optical waveguide side base layer 6. For this reason, compared with the case where the optical waveguide 2 is directly fixed to the surface of the substrate 1, the force S is firmly fixed on the substrate 1.

[0088] When the thickness of the optical waveguide side base layer 6 is 5 m or more, incident light tends to leak out, and there is a tendency that light loss cannot be sufficiently suppressed. In particular, this optical loss becomes more prominent as the optical path of the optical waveguide becomes longer. The thickness of the base layer 6 on the optical waveguide side can be controlled according to the cavity volume of the optical waveguide type 37, the extension area of the ultraviolet curable resin, the mass or volume of the ultraviolet curable resin measured at the time of dropping. . It can also be adjusted by monitoring with a non-contact measuring instrument when forming the optical waveguide. From the viewpoint of further improving the light coupling efficiency, the thickness of the base layer 6 on the optical waveguide side is preferably 3 111 or less.

[0089] (2) Lens forming step

FIG. 5 is a diagram schematically showing a lens forming step of forming a lens using a lens mold on a substrate. In fact, the force that forms a plurality of modules at once is simplified in FIG. 5 and only one optical waveguide is shown.

[0090] In the lens forming step, opposite to one surface of the substrate 1 on which the optical waveguide member is formed A lens member is formed on the other surface on the side. In this step, a light incident / exit lens is formed by ultraviolet curable resin molding at a position facing the light incident / exit inclined portion 2b provided in the optical waveguide 2. When molding the lens, positioning (alignment processing) is performed so that the optical axis of the lens is arranged at the center of the inclined portion 2b that enters and exits.

The configuration of the optical waveguide module manufacturing apparatus will be described with reference to FIG. The lens mold 29 formed as described above is set on the vertical drive stage 42 by vacuum suction. The lens mold 29 is provided with alignment marks ml, m2, m3, and m4 for aligning the lens mold 29 in advance when the optical waveguide module is formed. The substrate 1 on which the optical waveguide 2 has already been formed is set in the holder 43a and fixed by the substrate holder 43b. The optical waveguide module manufacturing equipment is equipped with multiple CCD cameras (four in this embodiment) that image alignment marks. With this CCD camera, the lens type alignment marks ml to m4 are imaged, the position coordinates are calculated in advance, and stored in the memory of the manufacturing equipment (with target registration! /).

In addition, the CCD camera images the alignment marks Ml, M2, M3, and M4 provided on the optical waveguide base layer 6 on which the optical waveguide is formed, and calculates the position coordinates. , Memorize it in memory (with object registration! /).

Details of the lens forming step will be described below based on FIG. As shown in FIG. 5 (a), a predetermined amount of UV curable resin 44 is applied dropwise onto the surface of the lens mold 29 on which the lens pattern is formed. The ultraviolet curable resin used for forming the lens of this embodiment has a curing shrinkage of 6 to 7%, a viscosity of S2600 to 2800 mPa ′ S (25 ° C.), and a refractive index after curing of 1.5536.

Next, the vertical drive stage 42 is raised, and the ultraviolet curable resin dropped on the lens mold is brought into close contact with the other surface of the substrate 1 subjected to the silane coupling treatment. FIG. 5 (b) shows a state in which the ultraviolet spring curable resin is brought into close contact with the other surface of the substrate 1 and the lens mold 29. In this manner, with the UV curable resin being in close contact with the other surface of the substrate 1 and the lens mold 29, the object coordinates (object coordinates (ml to m4) registered in advance with respect to the target coordinates (ml to m4) are registered. Align Ml to M4). At this time, the target coordinate position registered as the target and the object coordinate position registered as the object Based on the calculation result, alignment is performed by moving the holder 43a of the apparatus on which the substrate 1 is set in the horizontal direction. Thereafter, the vertical drive stage 42 is raised until the thickness of the ultraviolet curable resin between the lens mold 29 and the other surface of the substrate 1 reaches a desired thickness.

[0095] At the position where the thickness of the UV curable resin reaches a desired value, the alignment of the target coordinates (ml, m2, m3, m4) and the object coordinates (Ml, M2, M3, M4) is performed again. Do. The process of aligning the substrate 1 (optical waveguide) and the lens mold 29 based on the alignment mark is called “positioning step”.

[0096] After the positioning step is completed, ultraviolet (UV) light is irradiated. This makes it possible to obtain an optical waveguide module that is sufficiently excellent in light coupling efficiency with high positional accuracy. In addition, the integrated irradiation light quantity of ultraviolet irradiation can be set to, for example, lOOOOmj / cm ² .

Note that since no optical loss occurs in the lens-side base layer 7, it is less necessary to reduce the thickness than in the optical waveguide-side base layer 6. The thickness of the lens-side base layer 7 may be set so as to be within the lens design range and easy to mold. By making the lens-side base layer 7 sufficiently thick (10 or more), the occurrence of transfer failure due to curing shrinkage of the photo-curing resin is suppressed, so that ultraviolet rays can be collectively irradiated with high power.

Next, as shown in FIG. 5 (c), after the irradiation of UV light, the upper and lower drive stages 42 on which the lens mold 29 is set are lowered, and the lens member 30 is peeled off from the lens mold 29. As a result, the lens member 30 is formed on the other surface of the substrate 1 opposite to the surface on which the optical waveguide is formed.

[0099] By manufacturing a lens mold and an optical waveguide mold for molding a large number of lenses and optical waveguides, optical waveguide modules can be efficiently produced in large quantities. If the size per optical waveguide module is 20mm square, 5 x 5 optical waveguide modules are arranged in a matrix on a single substrate with a spacing of 0.3mm plus a distance of 0.3mm. Even so, it can be an area of 101.2 mm square. For example, by producing a lens mold and an optical waveguide mold of this size, the mass production effect of the optical waveguide module can be enhanced. An arbitrary number of alignment marks can be produced for each module. According to the positioning step of this embodiment, all modules are aligned at once. That's the power S.

[0100] When manufacturing a multi-piece lens mold and an optical waveguide mold in this manner, the stepper is used so that the inclined portion 2b of the optical waveguide 2 and the central portion of the lens 3 face each other. It can be positioned well.

[0101] That is, in the method of manufacturing a polymer optical waveguide module of the present embodiment, a step of forming an optical waveguide by press molding using a photo-curing resin on one surface of the mounting substrate, and the other of the mounting substrate Forming a light incident / exit lens on the surface by press molding using a photocurable resin at a position facing the 45 ° inclined portion of the optical waveguide formed in the step. Then, in the step of forming the light incident / exit lens, based on the alignment marks provided in advance on the molded waveguide surface side and the lens molding die side, the 45 ° inclined portion of the waveguide and the optical axis of the lens V, and then the lens side molding resin is cured.

[0102] By the above manufacturing method, a mounting substrate that supports the polymer optical waveguide, a polymer optical waveguide formed on one surface of the mounting substrate, and a lens formed on the other surface of the mounting substrate. Is obtained. The optical waveguide is provided with an inclined portion for reflecting light inside or outside the optical waveguide, and the position of the lens is a position facing the inclined portion formed in the optical waveguide. A pedestal is provided on the lens side of the mounting board, and the thickness of the pedestal is 10 to 25 mm when the SAG amount is 30 mm to 111 mm.

It should be noted that the present invention is not limited to the above embodiment. In the above embodiment, the optical waveguide module is manufactured in the order of the optical waveguide forming step and the lens forming step, but may be performed in the order of the lens forming step and the optical waveguide step. Further, in order to shorten the manufacturing time, the optical waveguide forming step and the lens forming step may be performed simultaneously. Further, the positioning step can be performed before the photocurable resin for forming at least one of the optical waveguide and the lens is cured. For example, the positioning step may be performed in the optical waveguide forming step, or the optical waveguide forming step and the lens. According to the present invention, the optical waveguide module and the manufacturing method thereof can be used for processing various fine optical element patterns and integrating them by using a polymer resin on a flat substrate.

Claims

The scope of the claims

[1] An optical waveguide module comprising a substrate, an optical waveguide formed on one surface side of the substrate, and a plurality of lenses formed on the other surface side of the substrate,

The optical waveguide has inclined portions at both ends thereof,

The plurality of lenses are respectively formed at positions facing the inclined portion with the substrate interposed therebetween.

The optical waveguide module and the plurality of lenses are both made of a cured resin, and the refractive index of the substrate is lower than the refractive index of any of the optical waveguide and the plurality of lenses. .

2. The optical waveguide module according to claim 1, wherein the substrate is made of glass.

3. The optical waveguide module according to claim 2, wherein the glass is quartz glass.

[4] The optical waveguide according to any one of [1] to [3], wherein the optical waveguide is formed on an optical waveguide-side base layer formed on one surface of the substrate. Waveguide module.

5. The optical waveguide module according to claim 4, wherein the thickness of the optical waveguide side base layer is 5 am or less.

[6] The plurality of lenses, respectively, are formed on a lens-side base layer formed on the other surface of the substrate; Optical waveguide module.

7. The lens according to claim 1, wherein the lens is a lens having a ridge formed on a peripheral edge.

An optical waveguide module according to item 6 of V, deviation.

[8] The optical waveguide module according to any one of [8] to [7], wherein a plurality of the optical waveguides are provided on one surface side of the substrate.

[9] The optical waveguide module according to any one of [1] to [8], wherein the plurality of optical waveguides are each simultaneously formed on one surface side of the substrate.

[10] Each of the plurality of lenses is simultaneously molded on the other surface side of the substrate. The optical waveguide module according to any one of claims 1 to 9, wherein

Yes

11. The optical waveguide module according to claim 10, wherein the lens is a coupling lens of the optical waveguide and an external optical system.

[12] With the first mold having a recess corresponding to the shape of the optical waveguide, the first resin precursor is brought into close contact with the substrate in a state where the recess is filled with the first resin precursor. An optical waveguide forming step of forming the optical waveguide having inclined portions at both ends on one surface side of the substrate by curing;

In the second mold having a recess corresponding to the shape of the lens, the second resin precursor is brought into close contact with the substrate and cured with the recess filled with the second resin precursor. A lens forming step of forming the lens on the other surface side of the substrate across the substrate,

Before curing at least one of the first resin precursor and the second resin precursor, the first mold is so arranged that the inclined portion of the optical waveguide and the lens are arranged to face each other. And a method of manufacturing an optical waveguide module, wherein at least one of the second molds is positioned.

[13] At least one of the first mold and the second mold has an alignment mark, and at least one of the first mold and the second mold with reference to the alignment mark. 13. The method of manufacturing an optical waveguide module according to claim 12, wherein the optical waveguide module is positioned.

[14] In the optical waveguide forming step,

The distance between the first mold and the substrate is adjusted so that an optical waveguide-side base layer having a thickness of 5 11 m or less is formed between the optical waveguide and the substrate. 14. A method for producing an optical waveguide module according to 12 or 13.

[15] The second mold is:

15. The method for manufacturing an optical waveguide module according to any one of claims 12 to 14, wherein the optical waveguide module has a recess corresponding to a lens having a ridge formed on its periphery.

[16] The collar is characterized in that it is formed continuously on the periphery of the lens. 16. A method for manufacturing an optical waveguide module according to claim 15.