JP2010156801A - Method for manufacturing polymer optical waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method that facilitates manufacturing of a polymer optical waveguide that has an electric conductive wire, that has small propagation loss and that is flexible. <P>SOLUTION: A metallic film 20, which is stuck to a first fixing sheet 2 having a first adhesive layer 6 on the surface, is cut with a blade 26 and divided. A first adhesive layer 18, which is formed on a first or third polymer layers 12, 16 of a three-layered laminated film 10, is stuck to the divided metallic film on the first fixing sheet. The first and the second adhesive layers are hardened, with the laminated film separated from the first fixing sheet, thereby transferring the divided metallic film on the first fixing sheet to the laminated film. After the metallic film transferred to the laminated film is stuck to the second fixing sheet 32 having a third adhesive layer 36 on the surface, the laminated film is cut off with the blade 28 from the opposite side from the metallic film. Then, by forming a plurality of grooves 24 for dividing the second polymer layer 14, a part of the side of a core 14a is formed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a polymer optical waveguide.

Electricity, which is widely used as a transmission medium in high-speed signal transmission, is approaching its limit and is expected to play a role of optical transmission. So-called optical interfaces that use optical wiring between equipment devices, between boards in equipment equipment, and between chips. Connection is drawing attention.
As a technique for enabling the optical interconnection, there is a polymer optical waveguide composed of a core made of a polymer that propagates light and has a high refractive index, and a clad made of a polymer that surrounds the core and has a smaller refractive index. In view of having flexibility, manufacturing costs can be kept low, and the like.

  However, the data handled by small information devices such as mobile devices has become larger than expected, and in parallel with the increasing demand for optical communication in devices, the devices themselves have become smaller, thinner, and lower in cost. The flexibility and low cost that the polymer optical waveguide has cannot be handled, and further flexibility and low cost are required.

  For example, as a simple method for producing a polymer optical waveguide specialized for a straight waveguide, a first layer serving as a cladding on a substrate and a second layer having a higher refractive index on the first layer are provided. A method of forming a waveguide structure by laminating and forming a waveguide core by forming a groove with a blade in the thickness direction from the second layer side, and further filling the groove with a clad material and curing it is proposed. (Patent Document 1).

On the other hand, ordinary polymer optical waveguides made of polymer materials are waveguides that can guide only optical signals. For example, low-speed electrical signals other than high-speed optical signal transmission between printed circuit boards or modules. When transmitting or supplying power, it is necessary to separately install a conductive wire in addition to the optical wiring.
Therefore, a polymer optical waveguide in which an electrical wiring pattern is formed on at least one of the front and back surfaces of the waveguide sheet (see Patent Document 2), and a polymer optical waveguide in which the optical wiring and the electrical wiring are built in the waveguide sheet (Patent Document) 3) is proposed.

JP-A-8-286064 JP 2001-311846 A JP 2007-140300 A

  It is an object of the present invention to provide a method for easily producing a flexible polymer optical waveguide having a conductive wire and a small propagation loss as compared with the case without this configuration.

The above problem is solved by the following means.
The invention of claim 1 includes (1) a step of attaching a metal film to a first fixing sheet having a curable first adhesive layer on the surface via the first adhesive layer, and (2) the first A step of cutting the metal film on the fixed sheet of 1 with a blade in the thickness direction to divide the metal film, (3) a first polymer layer serving as a cladding, and refraction from the first polymer layer A laminated film in which a second polymer layer that has a high rate and serves as a core through which light propagates, and a third polymer layer that has a refractive index lower than that of the second polymer layer and that serves as a cladding are laminated in this order. A curable second adhesive layer is formed on the first polymer layer or the third polymer layer, and the laminated film and the first fixing sheet are interposed via the second adhesive layer. A step of bonding the divided metal films; and (4) curing the first adhesive layer and the second adhesive layer; (5) a step of transferring the divided metal film to the laminated film by peeling the laminated film bonded to the divided metal film together with the divided metal film from the first fixing sheet; The metal film transferred to the laminated film and a second fixing sheet having a curable third adhesive layer on the surface are bonded together via the third adhesive layer, and then the laminated film is attached to the metal. A step of forming a part of the side surface of the core by forming a plurality of grooves for dividing the second polymer layer by cutting with a blade in a thickness direction from the surface opposite to the surface to which the film is transferred. And a method for producing a polymer optical waveguide.
The invention of claim 2 includes (1) a step of attaching a metal film to a first fixing sheet having a curable first adhesive layer on the surface via the first adhesive layer, and (2) the first A step of cutting the metal film on the fixed sheet of 1 with a blade in the thickness direction to divide the metal film, (3) a first polymer layer serving as a cladding, and refraction from the first polymer layer The refractive index after curing is the refractive index of the second polymer layer on the second polymer layer of the laminated film in which the second polymer layer serving as a core through which light is propagated is high. A curable second adhesive layer which is lower than the rate and becomes a clad after curing, and the laminated film and the divided metal film on the first fixed sheet are bonded together via the second adhesive layer And (4) curing the first adhesive layer and the second adhesive layer, and dividing the divided metal And (5) transferring to the laminated film, the step of transferring the divided metal film to the laminated film by peeling the laminated film together with the divided metal film from the first fixing sheet. The metal film and the second fixing sheet having a curable third adhesive layer on the surface were bonded together via the third adhesive layer, and then the metal film was transferred to the laminated film. Forming a part of the side surface of the core by forming a plurality of grooves for dividing the second polymer layer by cutting with a blade in a thickness direction from a surface opposite to the surface. A method for producing a polymer optical waveguide characterized by the above.
The invention of claim 3 is characterized in that, in the step (1), the surface of the metal film opposite to the side to be attached to the first fixing sheet is roughened. A method for producing a polymer optical waveguide according to claim 2.
According to a fourth aspect of the present invention, in the step (3), the second adhesive layer is formed of a semi-cured polymer material. A method for producing a polymer optical waveguide.
According to the invention of claim 5, after dividing the metal film in the step (2), before bonding the divided metal film and the laminated film in the step (3), the divided metal film A part is peeled from the said 1st fixing sheet, The manufacturing method of the polymer optical waveguide as described in any one of Claims 1-4 characterized by the above-mentioned.
According to a sixth aspect of the present invention, in the step (5), the groove is formed using the divided metal film as an alignment mark. Manufacturing method of molecular optical waveguide.

According to the first aspect of the present invention, there is provided a method by which a flexible polymer optical waveguide having a conductive wire and a small propagation loss can be easily manufactured as compared with the case without this configuration.
According to invention of Claim 2, compared with the case where it does not have this structure, the method by which a more flexible polymer optical waveguide which has a conductive wire and has a small propagation loss is manufactured simply is provided.
According to the third aspect of the present invention, there is provided a method in which a flexible polymer optical waveguide having a conductive wire and a small propagation loss is manufactured more easily and in a shorter time than the case without this configuration. The
According to invention of Claim 4, compared with the case where it does not have this structure, the method by which a flexible polymer optical waveguide which has a conductive wire and has a small propagation loss is manufactured more simply and reliably is provided. .
According to the fifth aspect of the present invention, a flexible polymer optical waveguide having an array of conductive wires with different space widths between the conductive wires and a small propagation loss can be obtained in comparison with the case without this configuration. A method of manufacturing is provided.
According to the sixth aspect of the present invention, a flexible polymer with high positional accuracy of the conductive wire and the waveguide core, easy optical coupling with other optical elements, and small propagation loss as compared with the case without this configuration. A method is provided in which an optical waveguide is simply manufactured.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that members having substantially the same functions and actions are given the same reference numerals or symbols throughout the drawings as appropriate, and redundant descriptions are omitted as appropriate. In addition, the drawings schematically show the shape, size, and positional relationship in order to facilitate understanding of the present invention, and the specific conditions shown in the drawings are merely examples, and these The form is not limited.

The present inventors first conducted the following research and examination on an optical waveguide having a conductive wire and a manufacturing method thereof.
For example, a waveguide sheet including a core and a clad surrounding the core is prepared, and a copper foil is bonded to the clad on one side. Next, after forming an etching mask with a resist on the copper foil by photolithography, unnecessary copper foil is dissolved and removed by etching. Furthermore, by removing the etching mask with a resist, a conductive line pattern made of copper is formed. Through the above steps, a waveguide having a conductive wire on at least one surface can be obtained.

  However, in the method of manufacturing a polymer optical waveguide having a conductive wire as described above, various thin film formation processes such as patterning, exposure / development, etching, etc. are performed in producing an electrical wiring pattern, an optical wiring pattern (core), etc. Therefore, a complicated and many process is required, and the manufacturing yield is likely to deteriorate.

  Furthermore, the waveguide and the electrical wiring pattern (conductive line) are formed in separate processes, that is, there is a limit to the accuracy of the mask or the alignment between the mask and the waveguide sheet. It tends to cause a decrease in position accuracy.

Further, for example, a metal film is further provided on a laminated film (hereinafter sometimes referred to as a three-layer film) composed of three layers in which a clad layer, a core layer, and a clad layer are laminated, and a groove is formed from the metal film side. When trying to form the waveguide core and the conductive line, the metal film is also cut at the same time when the waveguide core is formed. Therefore, the blade is clogged by the metal cutting powder, and the core side surface having high flatness is formed. As a result, the optical loss of the propagation light in the core may increase.
Furthermore, it is difficult to secure a degree of freedom in pattern design due to interference between the core pattern and the conductive pattern.

On the other hand, a three-layer film having a waveguide structure is prepared in advance by a manufacturing method as disclosed in Patent Document 1, and then a metal foil is bonded through an adhesive layer, and the metal is rotated with a blade rotating from the top of the metal foil. It can be considered that a polymer optical waveguide having a conductive side and a highly flat core side surface is formed by dividing the film to form a conductive line.
However, even when a three-layer film is produced by, for example, the spin coating method in the above-described method, the film thickness is uneven, and the three-layer film is a sum of the film thickness unevenness of the three layers. It becomes. In addition, when cutting the metal foil, if the film thickness unevenness of the three-layer film exceeds the film thickness unevenness of the tape that fixes the sample, the height unevenness of the sample fixing base, and the height accuracy of the blade, the metal foil Will be cut to the core located below, causing a loss of propagating light.
For example, by increasing the thickness of a three-layer film, film thickness unevenness and blade height accuracy are easily absorbed, but in this case, it is difficult to ensure the flexibility of the waveguide.

  In order to avoid cutting the core as described above, it is conceivable to form a conductive line by cutting at a place other than the presence of the core. The degree of freedom to lay is greatly limited.

  Furthermore, since the space between the conductive lines is formed by a cutting groove by a blade, the blade width becomes the groove width, and it is difficult to set a free space width. In order to realize a space width different from the blade width, it is possible to perform a plurality of times of cutting, but this leads to an increase in the number of processes.

Further, although it is conceivable to attach a conductive pattern above the waveguide core, the alignment accuracy between the waveguide core and the conductive pattern tends to be low. Also, in this case, it becomes difficult to observe the core of the polymer optical waveguide having the formed conductive wire from the side where the conductive wire is provided, and good alignment between the core and other light emitting / receiving elements cannot be performed, and the light Loss of the joint is likely to occur.
As a result of such studies and examinations, the present inventors have completed the present invention.

<First Embodiment>
With reference to FIGS. 1 and 2, a method for manufacturing a polymer optical waveguide according to the first embodiment will be described together with each component.
(1) A process of attaching a metal film to a fixed sheet (FIG. 1 (A))
The metal film 20 is bonded to the first fixing sheet 2 having the curable first adhesive layer 6 on the surface via the first adhesive layer 6.
Since the metal film 20 is later divided into conductive lines, a metal foil having excellent electrical characteristics is preferable, and is selected from gold, silver, copper, nickel, aluminum, or an alloy containing them.
Further, the surface of the metal foil 20 opposite to the surface to be attached to the first fixing sheet 2 is interposed through the laminated film 10 and another adhesive layer (second adhesive layer) 18 to be an optical waveguide in a later step. Therefore, it is required to secure a higher bonding strength, and therefore it is preferable that a rough surface treatment is applied. As the metal foil 20, it is preferable to select a copper foil from the viewpoints of low cost, easy surface roughening, corrosion resistance, and the like.

On the other hand, as the curable pressure-sensitive adhesive layer 6 of the first fixed sheet 2, a material that has adhesiveness and is cured by applying a specific stimulus from the outside to reduce the adhesive force is selected. Examples include an ultraviolet curable type, a thermosetting type, and an electron beam curable type. However, in consideration of simplicity and heat resistance of the laminated film 10 used in a later step, it is preferable to select an ultraviolet curable adhesive layer. In this case, in the subsequent step, the support 4 is a film having ultraviolet transparency so that the first adhesive layer 6 is cured by irradiating ultraviolet rays from the support 4 side of the first fixing sheet 2. Use.
As the first fixing sheet 2, it is preferable to select a dicing tape that satisfies these requirements.

(2) Step of dividing the metal film (FIG. 1B)
The metal film 20 on the first fixing sheet 2 is cut with a blade 26 in the thickness direction to divide the metal film 20.
For example, the conductive foil 20a is divided by cutting the metal foil 20 and a part of the first fixed sheet 2 in the thickness direction from the metal foil 20 side by a dicing saw having a blade 26 that rotates at high speed. , 20b, 20c. A dicing saw generally used in the manufacture of semiconductor devices has a scanning accuracy of μm level in cutting in a horizontal direction (in-plane direction) and a vertical direction (thickness direction) of a blade 26 that rotates at high speed. . Therefore, by using such a dicing saw, formation of a conductive pattern controlled at the μm level on the first fixed sheet 2 is realized in this step.

Since the thickness (width) of the blade 26 determines the distance (space) between the conductive lines, the blade thickness is appropriately determined. Moreover, since the space between the conductive lines is a factor that determines the characteristic impedance of the conductive line 20a, it may be appropriately determined including that. The conductive line width may be appropriately determined according to the purpose of the conductive line 20a, for example, a signal line, a ground line, a power supply line, or the like.
In this step, by dividing the metal foil 20, in addition to the conductive lines 20a used as the functional lines as described above, dummy conductive lines 20b and 20c not used as the functional lines are formed.

  The cutting depth of the blade 26 is cut to a part of the first fixed sheet 2 so as to surely divide the metal foil 20, but not so as to completely divide the first fixed sheet 2. However, the cutting of the adhesive layer 6 causes clogging of the blade 26, and the effect of the occurrence of burrs or the like on the division of the metal film 20 is likely to occur. Therefore, it is preferable that the blade 26 is not cut as deeply as possible into the adhesive layer 6. Furthermore, considering the blade height accuracy of the dicing saw, the height position of the blade tip during cutting is 5 μm or more and 30 μm or less in the thickness direction from the upper end (the surface of the adhesive layer 6) of the first fixed sheet 2. It is preferably 10 μm or more and 15 μm or less.

(3) A step of bonding the laminated film and the divided metal film (FIG. 1C)
First, a first polymer layer (referred to as a “lower cladding layer”) 12 serving as a cladding, and a core having a refractive index higher than that of the first polymer layer 12 and propagating light (appropriately “waveguide core”). A second polymer layer (referred to as a “core layer”) 14 to be 14a, and a third polymer layer (appropriately “appropriately“ A laminated film 10 on which 16 is laminated is prepared.

Since the first polymer layer 12 and the third polymer layer 16 are cladding, the refractive index is required to be smaller than that of the second polymer layer (core layer) 14. The difference in refractive index between the core layer 14 and each of the cladding layers 12 and 16 is appropriately determined from the spread angle of incident light to the waveguide, the numerical aperture (NA) of the optical device to be coupled, the bending diameter of the optical waveguide, and the like. .
As the polymer material constituting the core layer 14 and the clad layers 12 and 16, the core 14 a is particularly required to have high transparency to propagating light from the viewpoint of optical loss. Epoxy-based, acrylic-based, imide-based, norbornene Selected from the system. The lower clad layer 12 and the upper clad layer 16 do not need to be made of the same material, but are preferably made of the same material from the viewpoint of simplicity and optical design.

Since the thickness of the core layer 14 is the height of the core 14a, the thickness is determined in consideration of the coupling efficiency with the optical device coupled to the waveguide.
On the other hand, the clad layers 12 and 16 are preferably thin for the purpose of promoting the flexibility of the waveguide, as long as the mechanical strength is maintained. Although details will be described later, a thickness that compensates for the accuracy of forming the lower end of the groove 24 in the lower cladding layer 12 is required. For example, when the thickness of the core layer 14 is 50 μm, the total thickness including the adhesive layer 18 is preferably 150 μm or less, and more preferably 100 μm or less.

A curable second adhesive layer 18 is formed on the third polymer layer 16 of the laminated film 10.
The second adhesive layer 18 may also be selected from resins such as an ultraviolet curable type, a thermosetting type, and an electron beam curable type, but in consideration of simplicity and the heat resistance of the laminated film 10, an ultraviolet curable resin is particularly selected. It is preferable. However, since the conductive lines 20a, 20b, and 20c on the first fixing sheet 2 are transferred to the laminated film 10 via the second adhesive layer 18 in the subsequent process, the second adhesive layer 18 is the first The material is selected in consideration of the material of the adhesive layer 6 and the like.

The second adhesive layer 18 may be formed not on the third polymer layer 16 but on the first polymer layer 12.
The order of the step of dividing the metal film 20 in the step (2) and the step of preparing the laminated film 10 provided with the second adhesive layer 18 in the step (3) is not particularly limited. .

The laminated film 10 provided with the second adhesive layer 18 as described above and a metal film (referred to as “conductive line” or “conductive pattern” as appropriate) 20a, 20b divided on the first fixing sheet 2; 20 c is bonded through the second adhesive layer 18.
Viscosity, thickness, and curing of the second adhesive layer 18 so that the adhesive resin constituting the second adhesive layer 18 does not enter the groove 22 between the conductive lines and reach the first fixing sheet 2 when being bonded. A state etc. are determined suitably.

The thickness of the second adhesive layer 18 is preferably thinner considering the influence on the bending durability determined by the total thickness of the completed waveguide and the resin penetration into the groove 22, specifically 15 μm. The following is preferable, and 10 μm or less is more preferable.
In addition, as a method of creating the adhesive state of the second adhesive layer 18, it is one method to select a resin having a high viscosity, but the second adhesive layer 18 is formed of a semi-cured polymer material. May be. Here, the “semi-cured state” is a state before the resin for forming the second adhesive layer 18 is cured to some extent but before it is completely cured and loses adhesive force.

  As a method of creating such a semi-cured state, if it is an ultraviolet curable resin, a method of adjusting by irradiation intensity and irradiation time that does not reach the curing conditions, if it is a thermosetting resin, a temperature that does not reach the curing conditions, There is a method to adjust by heating time. In addition, a radical resin (for example, acrylic), which is an ultraviolet curable resin, is cured in a semi-cured state due to oxygen inhibition when oxygen in the atmosphere is contained during ultraviolet curing. There are two ways. Furthermore, a semi-cured film as the second adhesive layer 18 may be formed by simply leaving it alone or by using room temperature, light, volatilization, or the like.

(4) Step of transferring the divided metal film to the laminated film (FIG. 1D)
The first adhesive layer 6 and the second adhesive layer 18 are cured, and the laminated film 10 bonded to the divided metal films 20a, 20b, and 20c on the first fixing sheet 2 is divided into divided metal films. It peels from the 1st fixing sheet 2 with 20a, 20b, 20c. Thereby, the divided metal films 20 a, 20 b, and 20 c on the first fixed sheet 2 are transferred to the laminated film 10.

  For example, if the first adhesive layer 6 is an ultraviolet curable resin, the ultraviolet light is irradiated from the first fixing sheet 2 side, and if it is a thermosetting resin, heat is applied and cured. The first adhesive layer 6 cures not only the portion exposed between the conductive lines but also the portion between the first fixing sheet 2 and the conductive lines 20a, 20b, and 20c, resulting in a decrease in adhesive strength. As a result, the conductive lines 20a, 20b, and 20c are moved from the first fixed sheet 2 (first adhesive layer 6) to the second while the positional accuracy between the conductive lines on the first fixed sheet 2 is maintained. Is transferred to the laminated film 10 through the adhesive layer 18.

  In addition, the process which hardens the 1st adhesion layer 6 of the 1st fixing sheet 2 cuts the metal film | membrane 20 on the 1st fixing sheet 2, and divides | segments, Then, on this 1st fixing sheet 2 The divided metal films 20 a, 20 b, 20 c and the laminated film 10 may be bonded together and further performed before the laminated film 10 is peeled from the first fixing sheet 2. For example, when the metal film 20 fixed to the first fixing sheet 2 in the step (1) is divided by the blade 26 in the step (2) to form the conductive lines 20a, 20b, 20c, and then subjected to the curing process. If the conductive pattern is held on the first fixed sheet 2, the laminated film 10 may be bonded thereafter.

  On the other hand, the process of curing the second adhesive layer 18 of the laminated film 10 is performed after the divided metal films 20a, 20b, 20c on the first fixing sheet 2 and the laminated film 10 are bonded together, and then the laminated film 10 is bonded. May be peeled off from the first fixing sheet 2 and before the metal film 20a, 20b, 20c of the laminated film 10 is bonded to the second fixing sheet 32 and the laminated film 10 is cut. In any case, the conductive lines 20a, 20b, and 20c on the first fixing sheet 2 may be transferred and fixed to the laminated film 10 via the second adhesive layer 18.

The procedure for curing the adhesive layers 6 and 18 may be determined according to the material and the like. Specifically, the following procedures (a) to (c) may be mentioned.
(A) The conductive lines 20a, 20b, 20c on the first fixing sheet 2 and the second adhesive layer 18 of the laminated film 10 are bonded together, and the first adhesive layer 6 and the second adhesive layer 18 are joined together or After being cured sequentially, the laminated film 10 is peeled from the first fixed sheet 2.
(B) After the first adhesive layer 6 is cured, the conductive lines 20a, 20b, 20c on the first fixing sheet 2 and the second adhesive layer 18 of the laminated film 10 are bonded together to form the second adhesive layer. 18 is cured, and then the laminated film 10 is peeled off from the first fixing sheet 2.
(C) After the first adhesive layer 6 is cured, the conductive lines 20a, 20b, 20c on the first fixing sheet 2 and the second adhesive layer 18 of the laminated film 10 are bonded together, and the laminated film 10 is used as it is. It peels from the 1st fixing sheet 2, and the 2nd adhesion layer 18 is hardened after that.

(5) A step of forming a part of the side surface of the core by forming a groove in the laminated film (FIG. 2E)
First, the divided metal films (conductive lines) 20a, 20b, and 20c transferred to the laminated film 10 and the second fixing sheet 32 having the curable third adhesive layer 36 on the surface are provided as the third adhesive layer. Paste through 36. As the curable adhesive layer 36 of the second fixing sheet 32, a material that has adhesiveness and is cured by applying a specific stimulus from the outside to reduce the adhesive force is selected. Examples include an ultraviolet curable type, a thermosetting type, and an electron beam curable type. In consideration of simplicity and heat resistance of the laminated film 10, an ultraviolet curable adhesive layer is selected and irradiated with ultraviolet rays from the support 34 side. In order to cure the third adhesive layer 36, it is preferable to use a film having ultraviolet transparency as the support 34. As the second fixing sheet 32, it is preferable to select a dicing tape that satisfies these requirements.

Next, the laminated film 10 is cut with a blade 28 in the thickness direction from the surface opposite to the surface on which the metal films 20a, 20b, and 20c are transferred to form a plurality of grooves 24 that divide the second polymer layer 14. To do. Thereby, a part of the side surface of the core 14a (side surface in the thickness direction) is formed.
For example, the first polymer layer 12 and the second polymer layer 14 are cut in the thickness direction from the first polymer layer 12 side of the laminated film 10 by a dicing saw having a blade 28 that rotates at high speed. Thus, the side surface of the waveguide core 14 a is formed together with the groove 24. Here, in order to form the core 14a (side surface), the lower end of the blade 28 during cutting may be positioned at the lower end of the second polymer layer (core layer) 14. In consideration of the thickness accuracy, the film thickness unevenness of the laminated film 10, the film thickness unevenness of the fixed sheet, the height accuracy of the sample fixing base of the dicing saw, and the fact that the tip of the blade 28 is rounded, It is preferable to set the position below the lower end and not to cut up to the second adhesive layer 18. Specifically, the position of the lower end of the blade 28 at the time of cutting is in the third polymer layer 16 or the second adhesive layer 18, more specifically, 5 μm or more below the lower end of the core layer 14. The thickness is preferably 10 μm or more.

Further, when the laminated film 10 is cut to form the grooves 24, the divided metal films 20a, 20b, and 20c are preferably used as alignment marks. If the laminated film 10 is cut by using the divided metal films 20a, 20b, and 20c as alignment marks to form the grooves 24, the positional accuracy of the conductive wire 20a and the waveguide core 14a can be improved, and the completed polymer optical waveguide can be formed. When combining with other optical devices, the alignment is easy and high positional accuracy is realized because of the high-contrast conductive patterns 20a, 20b and 20c.
In this step, the core layer 14 is divided, and in addition to the waveguide core 14a, dummy cores 14b, 14c, and 14d that do not transmit light are also formed.

(6) Step of filling the clad material into the groove formed in the laminated film (FIG. 2 (F))
The groove 24 formed in the step (5) is filled with air, and since the refractive index is smaller than that of the core 14a at that time, a waveguide structure is formed and may be completed. From the viewpoint of light loss due to adhesion of foreign matter, strength of the waveguide itself, etc., it is preferable to fill and cure the curable resin as the cladding material 30 for embedding. An ultraviolet curable type, a heat curable type, an electron beam curable type, or the like is selected, but the ultraviolet curable type is preferable from the viewpoint of simplicity, and the first polymer layer 12 and the third polymer layer 16 are made of the same material. It is more preferable to select a curable resin.

(7) Step of peeling the polymer optical waveguide having conductive wires from the second fixing sheet (FIG. 2 (G))
The third adhesive layer 36 of the sheet is cured by irradiating ultraviolet rays from the second fixed sheet 32 side. As a result, the adhesive strength of the third adhesive layer 36 decreases, and the polymer optical waveguide 100 having the conductive wire 20a is peeled from the second fixing sheet 32.

(8) Step of filling a dielectric between conductive lines (FIG. 2 (H))
In the polymer optical waveguide having the conductive pattern on the surface obtained in the step (7), the conductive lines 20a, 20b and 20c are exposed, and the environment resistance is poor, and the space between the conductive lines (grooves 22) is air. For some reasons, impedance adjustment may be difficult. Therefore, it is preferable to fill the dielectric 38 between the conductive lines, or to further cover the conductive lines 20a, 20b, and 20c with the dielectric 38. The dielectric material is not particularly limited, but it is preferable to select an ultraviolet curable resin from the viewpoint of accurately controlling flexibility and dielectric constant. The dielectric constant between the conductive lines is a factor that determines the characteristic impedance of the conductive line 20a.

In the first embodiment, by applying the dicing technique as described above, the conductive pattern and the waveguide core are formed with high accuracy in separate steps, have conductive wires, have low propagation loss, and are highly flexible. The molecular optical waveguides 100 and 101 are manufactured by a simple method.
In addition, the polymer optical waveguides 100 and 101 having the conductive wire 20a manufactured by such a method have high alignment accuracy between the conductive pattern and the waveguide core. Highly efficient coupling with the device is realized.

<Second Embodiment>
FIG. 3 schematically shows a part of the manufacturing process of the polymer optical waveguide 102 according to the second embodiment. Since step (1) to step (2) are the same as in the first embodiment, description thereof is omitted.

(3) A step of bonding the laminated film and the divided metal film (FIG. 3A)
Here, a laminated film in which a first polymer layer 12 serving as a cladding and a second polymer layer 14 serving as a core 14a having a refractive index higher than that of the first polymer layer 12 and propagating light are laminated. 10B is prepared, and the second polymer layer 14 of the laminated film 10B has a cured refractive index lower than the refractive index of the second polymer layer 14 and becomes a clad after curing. An adhesive layer 16A is formed.

The thicknesses of the first polymer layer 12 and the second polymer layer 14 are preferably as thin as possible in consideration of the flexibility of the waveguide. On the other hand, the thickness is high from the point of forming the cutting groove 24 in a later step. It is preferable to have a thickness that compensates for thickness accuracy and film thickness unevenness. Considering both, the thickness of the first polymer layer 12 is preferably 5 μm or more and 30 μm or less, and more preferably 7 μm or more and 20 μm or less.
Further, since the uncured second adhesive layer 16A becomes a clad after curing, the refractive index after curing is required to be smaller than that of the second polymer layer (core layer) 14. Preferably, the first polymer layer 12 is formed of the same material. The laminated film 10B and the divided metal films 20a, 20b, and 20c on the first fixing sheet 2 are bonded to each other through the second adhesive layer 16A that also serves as the cladding layer.

(4) Step of transferring the divided metal film to the laminated film Next, the first adhesive sheet 6 of the first fixing sheet 2 and the second adhesive layer 18 of the laminated film 10B are cured and the divided metal The laminated film 10B on which the films 20a, 20b, and 20c are bonded is peeled from the first fixing sheet 2. Thereby, the divided metal films 20a, 20b, and 20c on the first fixed sheet 2 are transferred to the laminated film 10B.
Also in this case, as in the first embodiment, the first adhesive layer 6 and the second adhesive layer 18 may be cured together or sequentially.

After transferring the conductive pattern to the laminated film 10B, the steps (5) to (6) are performed as in the first embodiment, and the step (7) is performed as necessary. As a result, a polymer optical waveguide having the conductive wire 20a in which the conductive pattern is directly fixed on the third polymer layer 16 formed by curing the second adhesive layer 16A is manufactured (FIG. 3B). )).
Furthermore, if necessary, the space between the conductive lines may be further filled with a dielectric, or the conductive lines 20a, 20b, and 20c may be covered with a dielectric.

  In the second embodiment, since the adhesive layer 16A that fixes the conductive lines 20a, 20b, and 20c also serves as a cladding layer of the waveguide, the number of steps is reduced as compared with the first embodiment. By reducing the number of layers, the entire waveguide is thinned, so that the polymer optical waveguide 102 with the conductive wire 20a having further flexibility can be obtained.

<Third Embodiment>
FIG. 4 schematically shows a part of the manufacturing process of the polymer optical waveguide according to the third embodiment. Since step (1) to step (2) are the same as in the first embodiment, description thereof is omitted.

  After the metal film 20 on the first fixing sheet 2 is cut and divided in the step (2), the divided metal film 20a, 20b, 20c and the laminated film 10 are bonded to each other before being bonded. , 20b, and 20c are peeled off from the first fixed sheet 2 (FIG. 4A).

  For example, after the metal film 20 on the first fixing sheet 2 is cut and divided, the first adhesive layer 6 is cured to some extent or until the adhesive force is lost, and at least one of the conductive lines 20a, 20b, 20c. To form a space. Here, by hardening the first adhesive layer 6, the adhesive force between the conductive lines 20a, 20b, 20c and the first fixed sheet 2 is reduced, but the adsorption force remains, and easily It will not peel off.

After part of the conductive lines 20a, 20b, and 20c is peeled from the first fixing sheet 2, the steps (3) to (6) are performed as in the first embodiment, and if necessary. Step (7) is performed. Thereby, the polymer optical waveguide 103 having the conductive wire 20a is manufactured (FIG. 4B).
Furthermore, if necessary, the space between the conductive lines may be further filled with a dielectric 38, or the conductive lines 20a, 20b, and 20c may be covered with a dielectric.

  In the third embodiment, the distance (space) between the conductive lines is adjusted by peeling a part of the conductive lines 20a, 20b, and 20c, and a free space width can be formed without depending on the blade width. Realized. Note that the width (thickness) of the blade and the number of times of cutting may be adjusted.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

<Example 1>
The glossy surface on the opposite side of the copper foil (Nikko Metal Co., Ltd., thickness 12 μm) having one surface roughened was attached to a dicing tape having an ultraviolet curable adhesive layer on the surface. Subsequently, the rotation speed of the blade was set to 30000 rpm in a dicing saw (DAD321 manufactured by Disco Corporation) having a blade (thickness 100 μm) that rotates at high speed, and the copper foil and the dicing tape in the thickness direction from above the copper foil. A part was cut. Thus, four conductive lines having a copper line width of 500 μm, 250 μm, 250 μm, and 500 μm and a space between the lines of 100 μm were formed.

  On the other hand, a first layer made of an acrylic polymer with a refractive index of 1.51 and a thickness of 25 μm, a second layer made of an acrylic polymer with a refractive index of 1.55 and a thickness of 50 μm, on the second layer A three-layer laminated sheet (11 mm × 100 mm) having a third layer having the same material as the first layer and a thickness of 10 μm was prepared. Subsequently, an adhesive layer (thickness: 10 μm) made of an ultraviolet curable acrylic resin was formed on the first layer of the three-layer laminated sheet by spin coating.

  The dicing tape to which the conductive line is attached and the laminated sheet having the adhesive layer are bonded together by applying a certain pressure so that the rough surface of the conductive line and the adhesive layer of the laminated sheet are combined, and immediately UV light of 50 μW from the laminated sheet side. The adhesive layer was cured by irradiation with light for 10 minutes. Furthermore, after 70 seconds of ultraviolet light from the dicing tape side was irradiated for 45 seconds to cure the adhesive layer of the dicing tape, the conductive sheet was transferred onto the laminated sheet by peeling the laminated sheet from the dicing tape.

  The conductive pattern side of the laminated sheet to which the conductive pattern was transferred was bonded to another dicing tape (second dicing tape). With the dicing saw, the rotation speed of the blade is set to 30000 rpm, and the third layer, the second core layer, and a part of the first layer are formed in the thickness direction from the third layer side of the laminated sheet. A plurality of grooves were formed by cutting. As a result, cores having a height of 50 μm and a width of 50 μm were formed at intervals of 500 μm.

Subsequently, the groove formed in the laminated sheet was filled with the ultraviolet curable polymer material, which is the same material as the first layer and the third layer, and cured by irradiating ultraviolet rays from the laminated sheet side.
Next, after irradiating ultraviolet rays from the second dicing tape side to cure the adhesive layer of the dicing tape, the laminated sheet was peeled off.
Through the above process, a flexible polymer optical waveguide having a conductive wire having a total thickness of 105 μm and a length of 100 mm was completed.

  The polymer optical waveguide was bent to a radius of 2 mm, and the propagation loss of the waveguide was measured. As a result, it was 0.1 dB / cm. Furthermore, as a result of observing with a oscilloscope, a 500 μm wide conductive line is a ground line, a 250 μm line is a signal line, a differential 0.4 Vpp PRBS (7 stages), 50 Mbps signal is transmitted to the signal line. A good eye diagram was shown.

<Example 2>
Instead of the step of forming the adhesive layer on the three-layer laminated sheet in Example 1, the first layer is made of an acrylic polymer and has a refractive index of 1.51 and a thickness of 25 μm and the acrylic polymer, and is refracted. A two-layer laminated sheet having a second layer with a rate of 1.55 and a thickness of 50 μm is prepared, and an uncured clad layer / adhesive layer made of the same material as the first layer by spin coating on the second layer (Thickness 10 μm) was formed.
A flexible polymer optical waveguide having a conductive wire having a total thickness of 90 μm was completed in the same manner as in Example 1 except for the above steps.

<Example 3>
The glossy surface on the opposite side of the copper foil (Nikko Metal Co., Ltd., thickness 12 μm) having one surface roughened was attached to a dicing tape having an ultraviolet curable adhesive layer on the surface. Subsequently, the rotation speed of the blade was set to 30000 rpm with a dicing saw (DAD321 manufactured by DISCO Corporation) having a blade (thickness 100 μm) that rotates at high speed, and the copper foil and dicing tape The part was cut. Thus, seven conductive lines having a copper line width of 500 μm, 100 μm, 250 μm, 100 μm, 250 μm, 100 μm, and 500 μm and a space between the lines of 100 μm were formed.

Subsequently, 70 μW ultraviolet light was irradiated from the dicing tape side for 45 seconds to cure the adhesive layer of the dicing tape, and then the conductive line having a line width of 100 μm was peeled off.
Thereafter, the same steps as in Example 1 were performed.
Thus, a flexible polymer optical waveguide having four linear conductive line patterns having a line width of 500 μm, 250 μm, 250 μm, 500 μm, and a space of 300 μm was manufactured.

  As mentioned above, although each embodiment and an Example were described, it is not limited to this. For example, in the second embodiment, after a part of the divided metal layer on the first fixed sheet is peeled off, the laminated film may be bonded.

It is a figure which shows roughly the process of the first half of the manufacturing method of the polymer optical waveguide which concerns on 1st Embodiment. It is a figure which shows roughly the process of the latter half of the manufacturing method of the polymer optical waveguide which concerns on 1st Embodiment. It is a figure which shows schematically a part of process of manufacturing the polymer optical waveguide which concerns on 2nd Embodiment. It is a figure which shows roughly a part of process of manufacturing the polymer optical waveguide which concerns on 3rd Embodiment.

Explanation of symbols

2 First Fixed Sheet 4 Support 6 First Adhesive Layer 10 Laminated Film 12 First Polymer Layer (Lower Cladding Layer)
14 Second polymer layer (core layer)
14a Cores 14b, 14c, 14d Dummy core 15 Second adhesive layer (cladding layer)
16 Third polymer layer (upper clad layer)
18 Second adhesive layer 20 Metal film (metal foil)
20a Conductive lines 20b and 20c Dummy conductive lines 22 and 24 Grooves 26 and 28 Blade 30 Embedded cladding 32 Second fixing sheet 34 Support 36 Third adhesive layer 38 Dielectric

Claims (6)

(1) A step of attaching a metal film to the first fixing sheet having a curable first adhesive layer on the surface via the first adhesive layer;
(2) cutting the metal film on the first fixed sheet with a blade in the thickness direction and dividing the metal film;
(3) From a first polymer layer serving as a cladding, a second polymer layer serving as a core through which light is propagated and having a higher refractive index than the first polymer layer, and from the second polymer layer A curable second adhesive layer is formed on the first polymer layer or the third polymer layer of a laminated film having a low refractive index and a third polymer layer serving as a cladding laminated in this order. And bonding the laminated film and the divided metal film on the first fixing sheet through the second adhesive layer;
(4) The first adhesive layer and the second adhesive layer are cured, and the laminated film bonded to the divided metal film is peeled from the first fixed sheet together with the divided metal film. A step of transferring the divided metal film to the laminated film;
(5) After laminating the metal film transferred to the laminated film and a second fixing sheet having a curable third adhesive layer on the surface via the third adhesive layer, the laminated film A portion of the side surface of the core is formed by forming a plurality of grooves for dividing the second polymer layer by cutting with a blade in a thickness direction from the surface opposite to the surface to which the metal film is transferred. Forming, and
A method for producing a polymer optical waveguide, comprising: (1) A step of attaching a metal film to the first fixing sheet having a curable first adhesive layer on the surface via the first adhesive layer;
(2) cutting the metal film on the first fixed sheet with a blade in the thickness direction and dividing the metal film;
(3) The first layer of the laminated film in which a first polymer layer serving as a cladding and a second polymer layer serving as a core through which light is propagated have a refractive index higher than that of the first polymer layer. On the second polymer layer, a cured second adhesive layer that has a refractive index after curing lower than that of the second polymer layer and becomes a clad after curing is formed, and the second adhesive layer Bonding the laminated film and the divided metal film on the first fixing sheet via,
(4) The first adhesive layer and the second adhesive layer are cured, and the laminated film bonded to the divided metal film is peeled from the first fixed sheet together with the divided metal film. A step of transferring the divided metal film to the laminated film;
(5) After laminating the metal film transferred to the laminated film and a second fixing sheet having a curable third adhesive layer on the surface via the third adhesive layer, the laminated film A portion of the side surface of the core is formed by forming a plurality of grooves for dividing the second polymer layer by cutting with a blade in a thickness direction from the surface opposite to the surface to which the metal film is transferred. Forming, and
A method for producing a polymer optical waveguide, comprising:   3. The height according to claim 1, wherein in the step (1), a surface of the metal film opposite to a side to be attached to the first fixing sheet is roughened. Manufacturing method of molecular optical waveguide.   The said 2nd adhesion layer is formed in the said process (3) with the polymeric material of a semi-hardened state, The manufacture of the polymer optical waveguide as described in any one of Claims 1-3 characterized by the above-mentioned. Method.   After dividing the metal film in the step (2) and before bonding the divided metal film and the laminated film in the step (3), a part of the divided metal film is added to the first film. It peels from a fixing sheet, The manufacturing method of the polymer optical waveguide as described in any one of Claims 1-4 characterized by the above-mentioned.   6. The method of manufacturing a polymer optical waveguide according to claim 1, wherein in the step (5), the groove is formed using the divided metal film as an alignment mark.

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