JP5321797B2 - Manufacturing method of optical waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple manufacturing method of an optical waveguide, and to provide a manufacturing method of an optical waveguide capable of acquiring a clear core pattern. <P>SOLUTION: This manufacturing method of the optical waveguide includes: an active radiation hardening polymer layer manufacturing process for manufacturing an active radiation hardening polymer layer having a maleimide group containing a low molecular weight compound to be reacted with the maleimide group by irradiating an active radiation; the first irradiation process for putting a pattern-shaped mask on the active radiation hardening polymer layer, and irradiating the polymer layer with the active radiation; a low molecular weight compound evaporation process for evaporating the low molecular weight compound from an unexposed part not irradiated with the active radiation out of the active radiation hardening polymer layer under a heated or depressurized condition; and the second irradiation process for irradiating the whole active radiation hardening polymer layer with the active radiation. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an optical waveguide manufacturing method for easily manufacturing an optical waveguide composed of a core and a clad having a refractive index lower than that of the core and surrounding the core.

  Data transfer using optical frequency carriers generated from light sources such as lasers or light emitting diodes is becoming increasingly important. One means for guiding such an optical frequency carrier wave from one point to another is an optical waveguide. The optical waveguide includes a first medium (core) that is substantially transparent to light of an optical frequency carrier wave, and a second medium (cladding) having a lower refractive index than the first medium. The first medium is surrounded by the second medium or encapsulated inside the second medium. The light introduced from the end of the first medium undergoes total internal reflection at the boundary with the second medium, and is thereby guided along the axis of the first medium. Often used as the first medium is a glass formed into an elongated fiber shape. However, glass optical fiber is convenient for long-distance data transport, but it is not preferable for complicated high-density circuits because circuit density causes problems in use and costs. . On the other hand, polymer materials are promising because they can create components that are reasonably cost, reliable, passive and practical, yet perform the functions required for integrated optics. .

  Therefore, in recent years, research for forming an optical waveguide from a polymer material using a photocuring method has been actively conducted. Optical waveguides are particularly required to have good optical properties in the wavelength region (around 850 nm) used for optical wiring, and solder heat resistance for products that require mounting processes for electrical or electronic components. The In particular, in recent years, there has been a demand for solder lead-free due to environmental conservation considerations, and since the solder reflow temperature has increased, heat resistance that can maintain the shaped shape even at high temperatures has become necessary.

  For example, a copolymer of maleimide and norbornene, which is excellent in heat resistance, etching resistance, adhesiveness, and the like, has been studied as an optical material (Patent Document 1, Patent Document 2, and Patent Document 3).

JP 2001-200018 A (Claims) JP 11-228536 A (Claims) JP-A-11-322855 (Claims)

  Conventionally, the formation of an optical waveguide from a polymer material using a photocuring method has been performed by the steps shown in FIGS. 7 to 11 are schematic cross-sectional views showing a process of forming an optical waveguide from a polymer material using a conventional photocuring method. First, as shown in FIG. 7, a core polymer layer 32 made of a polymer that is cured by light irradiation is formed on the lower cladding 31, and the surface of the core polymer layer 32 is masked with a photomask 33. For example, the ultraviolet ray 34 is irradiated. Thus, as shown in FIG. 8, the core polymer layer 32 includes an exposed portion 35 in which the core polymer is cured by being irradiated with the ultraviolet ray 34, and a core that is not cured without being irradiated with the ultraviolet ray 34. It becomes the unexposed part 36 which is a polymer for use. Then, the unexposed portion 36 that has not been cured in the core polymer layer 32 is removed with a developer, and only the core portion 37 is formed on the lower cladding layer 31 as shown in FIG. Next, as shown in FIG. 10, an upper clad polymer layer 38 is formed on the lower clad layer 31 and the core portion 37. Next, the upper clad polymer layer 38 is irradiated with ultraviolet rays to cure the upper clad polymer layer 38 to form an upper clad 39 (FIG. 11). As a result, an optical waveguide whose core is surrounded by the clad is formed.

  In such a conventional method for manufacturing an optical waveguide, there is a problem that a manufacturing process is complicated because a process of developing an unexposed portion with a developer is essential. Moreover, since the photocurable resin used for formation of an optical waveguide, for example, the resin described in the said patent documents 1-3, the hardening rate by light irradiation is slow, you have to lengthen light irradiation time. Therefore, there is a problem that a dark reaction that is often seen in a chemically amplified resist is induced, and as a result, the photomasked portion is cured and a clear core pattern cannot be formed.

  Accordingly, an object of the present invention is to provide a simple method for manufacturing an optical waveguide. Furthermore, the objective of this invention is providing the manufacturing method of the optical waveguide from which a clear core pattern is obtained.

  As a result of intensive studies to achieve the above object, the present inventors have (1) irradiating active radiation to the polymer layer when producing a polymer layer comprising an active radiation curable polymer having a maleimide group. Then, a low molecular weight compound that reacts with the maleimide group is contained, and then, when the polymer layer is masked in a pattern shape and irradiated with actinic radiation, the maleimide groups in the exposed polymer layer are partially crosslinked. Since the low molecular weight compound reacts with the maleimide group while reacting, the low molecular weight compound is strongly held in the polymer layer in the exposed area. (2) On the other hand, the low molecular weight in the polymer layer in the unexposed area. Since the compound does not react with the maleimide group, when the polymer layer is heated or decompressed, only the low molecular weight compound in the polymer layer in the unexposed area is volatilized. 3) This makes it possible to cause a difference in refractive index between the exposed area and the unexposed area depending on whether or not the polymer layer contains the low molecular weight compound. (4) Therefore, a development step is performed. Even if not, since the core portion and the intermediate layer cladding portion can be formed between the lower layer cladding and the upper layer cladding, the optical waveguide can be manufactured by a simple method, and (5) the crosslinking reaction between maleimide groups. Compared to the above, since the reaction between the low molecular weight compound and the maleimide group is likely to occur, the irradiation amount of the active radiation in the first irradiation step can be reduced, so that a clear core pattern can be obtained and the present invention is obtained. Completed.

That is, the present invention comprises an actinic radiation curable polymer layer production step of producing an actinic radiation curable polymer layer having a maleimide group containing a low molecular weight compound that reacts with a maleimide group by irradiation with actinic radiation;
A first irradiation step of irradiating the active radiation curable polymer layer with a pattern-shaped mask and irradiating with active radiation;
A low molecular weight compound volatilization step for volatilizing the low molecular weight compound from an unexposed portion of the active radiation curable polymer layer that has not been irradiated with the active radiation under heating or reduced pressure;
A second irradiation step of irradiating the entire actinic radiation curable polymer layer with actinic radiation;
The present invention provides a method for manufacturing an optical waveguide characterized by comprising:

  According to the present invention, a simple method for manufacturing an optical waveguide can be provided. Furthermore, according to the present invention, it is possible to provide a method of manufacturing an optical waveguide from which a clear core pattern can be obtained.

The method for producing an optical waveguide of the present invention comprises an active radiation curable polymer layer preparation step of preparing an active radiation curable polymer layer having a maleimide group containing a low molecular weight compound that reacts with a maleimide group by irradiating with active radiation. ,
A first irradiation step of irradiating the active radiation curable polymer layer with a pattern-shaped mask and irradiating with active radiation;
A low molecular weight compound volatilization step for volatilizing the low molecular weight compound from an unexposed portion of the active radiation curable polymer layer that has not been irradiated with the active radiation under heating or reduced pressure;
A second irradiation step of irradiating the entire actinic radiation curable polymer layer with actinic radiation;
Is a manufacturing method of an optical waveguide having Hereinafter, the low molecular weight compound that reacts with the maleimide group by irradiation with the actinic radiation is also referred to as a low molecular weight compound (a), and the actinic radiation curable polymer having the maleimide group is actinic radiation curable. Also referred to as polymer (b).

  And in the manufacturing method of the optical waveguide of this invention, the form using the low molecular weight compound which acts as a compound which lowers the refractive index of the hardened | cured material of this actinic radiation curable polymer (b) as this low molecular weight compound (a). (Hereinafter also referred to as the optical waveguide manufacturing method (1) of the present invention) and a form using a low molecular weight compound that acts as a compound for increasing the refractive index of the cured product of the actinic radiation curable polymer (b) ( Hereinafter, it is also referred to as a manufacturing method (2) of the optical waveguide of the present invention.

  The manufacturing method (1) of the optical waveguide of this invention is demonstrated with reference to FIGS. FIGS. 1-6 is typical sectional drawing which shows the example of a form of the manufacturing method (1) of the optical waveguide of this invention. 1 to 6, the front and back direction of the paper is the light transfer direction of the optical frequency carrier wave.

  First, as shown in FIG. 1, the actinic radiation curable polymer (b) layer 2 containing the low molecular weight compound (a) is made of a material having a lower refractive index than the cured product of the actinic radiation curable polymer (b). It forms on the lower clad 1 which becomes (active radiation curable polymer layer preparation step).

  Next, as shown in FIG. 2, the surface of the actinic radiation curable polymer (b) layer 2 is masked with a photomask 3 and irradiated with ultraviolet rays 4 (first irradiation step). As a result, as shown in FIG. 3, the active radiation curable polymer (b) layer 2 is irradiated with the ultraviolet ray 4, that is, the exposed portion 6 and the portion not irradiated with the ultraviolet ray 4, That is, the unexposed part 5 exists. And in this exposure part 6, since reaction of a part of maleimide groups of this actinic radiation curable polymer (b) and reaction of this low molecular weight compound (a) and a maleimide group occur, this low molecular weight compound (a ) Is a structure after photoreaction with a maleimide group, and is firmly bonded to the actinic radiation curable polymer (b) layer 2, while in the unexposed area 5, the low molecular weight compound (a) Is present without being bonded to the actinic radiation curable polymer (b) layer 2.

  In the first irradiation step, depending on the type of the low molecular weight compound (a), a polymerization reaction between the low molecular weight compounds (a) occurs due to irradiation with actinic radiation. When the polymerization reaction between the low molecular weight compounds (a) also occurs, in the exposure unit 6, two or more low molecular weight compounds (a) are polymerized during the first irradiation step, and the low molecular weight compounds (a) are polymerized. A polymer of the molecular weight compound (a) is produced, and a reaction between the produced polymer of the low molecular weight compound (a) and the maleimide group also occurs.

  Subsequently, the actinic radiation curable polymer (b) layer 2 is heated together with the lower cladding 1 or placed under reduced pressure to volatilize the low molecular weight compound (a) from the unexposed portion 5 (low molecular weight compound Volatilization process). As a result, the unexposed portion 5 becomes an unexposed portion 7 from which the low molecular weight compound (a) has been volatilized and removed (hereinafter also referred to as a low molecular weight compound removed unexposed portion 7) (FIG. 4).

  Next, as shown in FIG. 5, the entire actinic radiation curable polymer (b) layer 2 is irradiated with ultraviolet rays 4 to irradiate all the actinic radiation curable polymer (b) layer 2 with the actinic radiation curable polymer (b) layer 2. (B) is cured (second irradiation step). Thereby, the actinic radiation curable polymer (b) layer 2 becomes a cured product layer 11 of the actinic radiation curable polymer (b), and at this time, the exposed portion 6 becomes an intermediate layer clad portion 8, The low molecular weight compound removal unexposed portion 7 becomes a core portion 9.

  Next, an upper clad 10 made of a material having a refractive index lower than that of the cured product of the actinic radiation curable polymer (b) is produced on the intermediate clad portion 8 and the core portion 9 to obtain an optical waveguide 20. .

  In the optical waveguide 20, the intermediate clad portion 8 has a structure after the low molecular weight compound (a) that lowers the refractive index of the cured product of the active radiation curable polymer (b) reacts with the maleimide group. And present in the cured product. On the other hand, the core part 9 is composed only of a cured product of the actinic radiation curable polymer (b), or the low molecular weight compound (a) in the core part 9 is reacted with a maleimide group. Even if it is bonded to the cured product in the structure, the refractive index of the core portion 9 is higher than that of the intermediate layer cladding portion 8 because it is smaller than the intermediate layer cladding portion 8. Therefore, the core portion 9 is surrounded by the lower clad 1, the intermediate clad portion 8 and the upper clad 10 having a refractive index lower than that, so that the optical waveguide 20 transmits light of an optical frequency carrier wave. Functions as an optical waveguide to be transported.

  In addition, the form example of FIGS. 1-6 uses the low molecular weight compound which acts as a compound which lowers the refractive index of the hardened | cured material of this actinic radiation curable polymer (b) as this low molecular weight compound (a) ( Although it is an example of the manufacturing method (1)) of the optical waveguide of the present invention, the optical waveguide manufacturing method of the present invention includes curing the active radiation curable polymer (b) as the low molecular weight compound (a). There is also a form using a low molecular weight compound that acts as a compound for increasing the refractive index of the product, that is, the method (2) for producing an optical waveguide of the present invention. And in the manufacturing method (2) of the optical waveguide of this invention, the exposure part irradiated with actinic radiation by this 1st irradiation process is light-guided through this low molecular weight compound volatilization process and this 2nd irradiation process. The unexposed portion that has become the core portion of the waveguide and has not been irradiated with the active radiation in the first irradiation step becomes the intermediate layer cladding.

  The active radiation curable polymer (b) according to the method for producing an optical waveguide of the present invention has a maleimide group in the polymer molecule. Then, by irradiating the actinic radiation curable polymer (b) with actinic radiation, the maleimide group in one polymer undergoes a crosslinking reaction with the maleimide group in the other polymer to dimerize. As a result, the actinic radiation curable polymer (b) is crosslinked with a maleimide group dimer, photocured, and becomes a cured product.

  The actinic radiation curable polymer (b) is a polymer having a cyclohexane skeleton or a cyclopentane skeleton as a whole or a part of the main chain and a maleimide group as a side chain, and has excellent transparency in the vicinity of 850 nm. In addition, since it exhibits physical properties with flexibility, it is preferable as a multimode polymer optical waveguide material.

The actinic radiation curable polymer (b) is selected from one or more structural units selected from the structural units represented by the following general formula (1) and from the structural units represented by the following general formula (3). A polymer in which one or more structural units are randomly copolymerized and the molar ratio of the structural units represented by the following general formula (1) is 10 to 100% (hereinafter, such a polymer) Is also referred to as actinic radiation curable polymer (b-1).) Is preferable in that crosslinking can be sufficiently performed and the toughness of the waveguide film can be increased.
General formula (1):

(In the formula, _{X, -CH 2 -, - CH 2} -CH 2 - or -O- .m, among ^{.R 1, R 2,} R ³ and ^{R 4} is an integer from 0 to 5 Is one of the following general formula (2):

[In the formula, A represents a methylene group; a linear or branched hydrocarbylene group having 2 to 6 carbon atoms; a linear or branched halohydrocarbylene group having 2 to 6 carbon atoms; Or a branched perhalocarbylene group having 2 to 6 carbon atoms; a substituted or unsubstituted cyclic or polycyclic hydrocarbylene group having 5 to 12 carbon atoms; a substituted or unsubstituted cyclic group having 5 to 12 carbon atoms Or a polycyclic halohydrocarbylene group; or a substituted or unsubstituted cyclic or polycyclic perhalocarbylene group having 5 to 12 carbon atoms. R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms, and may be the same or different, and R ⁵ and R ⁶ may form a ring having 3 to 8 carbon atoms. . ]
Is a maleimide group represented by: The rest of R ¹ , R ² , R ³ and R ⁴ is a hydrogen atom; a linear or branched hydrocarbyl group having 1 to 25 carbon atoms; a linear or branched halohydrocarbyl group having 1 to 25 carbon atoms. Or a linear or branched perhalocarbyl group having 1 to 25 carbon atoms, which may be the same or different. )
General formula (3):

(Wherein, Y _{is, -CH 2 -, - CH 2} -CH 2 - or -O- .n is at least ^{.R 7, R 8,} R ⁹ and ^{R 10} is an integer from 0 to 5 One is a linear, branched or cyclic C1-C25 hydrocarbyl group having a heteroatom selected from one or more oxygen atoms, nitrogen atoms, sulfur atoms and silicon atoms; A linear, branched or cyclic halohydrocarbyl group having 1 to 25 carbon atoms having a heteroatom selected from oxygen atom, nitrogen atom, sulfur atom and silicon atom; one or more oxygen atoms, nitrogen atom, A linear, branched or cyclic perhalocarbyl group having 1 to 25 carbon atoms having a heteroatom selected from a sulfur atom and a silicon atom; selected from one or more oxygen atoms, nitrogen atoms, sulfur atoms and silicon atoms Heteroatom An aryl group having 1 to 25 carbon atoms; an aralkyl pendant group having 1 to 25 carbon atoms having a hetero atom selected from one or more oxygen atoms, nitrogen atoms, sulfur atoms, and silicon atoms; linear, branched Or a linear, branched or cyclic halohydrocarbyl group having 1 to 25 carbon atoms; a linear, branched or cyclic perhalocarbyl group having 1 to 25 carbon atoms; carbon An aryl group having 1 to 25 carbon atoms; or an aralkyl pendant group having 1 to 25 carbon atoms, and the remainder of R ⁷ , R ⁸ , R ⁹ and R ¹⁰ is a hydrogen atom.)

Examples of the maleimide group represented by the general formula (2) include a structure represented by the following formula (2-1).
Formula (2-1):

  In the present invention, the “hydrocarbyl group” is a group containing a carbon skeleton in which each carbon atom is appropriately substituted with at least one hydrogen atom. That is, the “hydrocarbyl group” is a hydrocarbon group or a group in which a part of the hydrogen atoms of the hydrocarbon group is substituted with a substituent having a nitrogen atom or a substituent having an oxygen atom.

  Specific examples of the hydrocarbyl group include a linear or branched alkyl group having 1 to 25 carbon atoms; a linear or branched alkenyl group having 2 to 24 carbon atoms; a linear or branched group. An alkynyl group having 2 to 24 carbon atoms; a cycloalkyl group having 5 to 25 carbon atoms having a linear or branched group; an aryl group having 6 to 24 carbon atoms; an aralkyl group having 7 to 24 carbon atoms; More specifically, benzyl group, phenylpropyl group, naphthylmethyl group, naltylethyl group and the like can be mentioned.

  In the present invention, the “halohydrocarbyl group” means that at least one hydrogen atom (but not all hydrogen atoms) of the hydrocarbyl group is a halogen atom such as a chlorine atom, a bromine atom, an iodine atom, or a fluorine atom. A group substituted with an atom. As the halohydrocarbyl group, specifically, for example, at least one hydrogen atom (but not all hydrogen atoms) of a linear or branched alkyl group having 1 to 25 carbon atoms is a halogen atom. A substituted group; a group in which at least one hydrogen atom (but not all hydrogen atoms) of a linear or branched alkenyl group having 2 to 24 carbon atoms is substituted with a halogen atom; A group in which at least one hydrogen atom (but not all of the hydrogen atoms) of the branched alkynyl group having 2 to 24 carbon atoms is substituted with a halogen atom; a carbon number of 5 having a linear or branched group A group in which at least one hydrogen atom (but not all hydrogen atoms) of a cycloalkyl group of ˜25 is substituted with a halogen atom; at least one hydrogen atom of an aryl group having 6 to 24 carbon atoms A group in which (but not all hydrogen atoms) is substituted with a halogen atom; at least one hydrogen atom (but not all hydrogen atoms) in an aralkyl group having 7 to 24 carbon atoms is substituted with a halogen atom Group.

  In the present invention, the “perhalocarbyl group” is a group in which all hydrogen atoms of the hydrocarbyl group are substituted with halogen atoms such as a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom. Specific examples of the perhalocarbyl group include, for example, a group in which all hydrogen atoms of a linear or branched alkyl group having 1 to 25 carbon atoms are substituted with halogen atoms; linear or branched carbon A group in which all hydrogen atoms of the alkenyl group having 2 to 24 are substituted with halogen atoms; a group in which all hydrogen atoms of the linear or branched alkynyl group having 2 to 24 carbon atoms are substituted with halogen atoms; A group in which all the hydrogen atoms of a cycloalkyl group having 5 to 25 carbon atoms having a linear or branched group are substituted with a halogen atom; and all the hydrogen atoms in an aryl group having 6 to 24 carbon atoms are halogen atoms. A substituted group; a group in which all the hydrogen atoms of an aralkyl group having 7 to 24 carbon atoms are substituted with halogen atoms.

  Examples of the alkyl group related to the hydrocarbyl group include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, Examples include, but are not limited to, a heptyl group, an octyl group, a nonyl group, a decyl group, and a dodecyl group. Examples of the alkenyl group related to the hydrocarbyl group include, but are not limited to, a vinyl group, an allyl group, and a propenyl group. Examples of the alkynyl group related to the hydrocarbyl group include, but are not limited to, an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, and a 2-butynyl group. Examples of the cycloalkyl group related to the hydrocarbyl group include, but are not limited to, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Examples of the aryl group related to the hydrocarbyl group include, but are not limited to, a phenyl group, a biphenyl group, a naphthyl group, and an anthracenyl group. Examples of the aralkyl group related to the hydrocarbyl group include, but are not limited to, a benzyl group and a phenethyl group. The halohydrocarbyl group is a group in which at least one hydrogen atom (but not all hydrogen atoms) of these groups is substituted with a halogen atom, and the perhalocarbyl group is a group of these groups. A group in which all hydrogen atoms are substituted with halogen atoms.

  Moreover, the hydrocarbyl group having a heteroatom selected from one or more oxygen atoms, nitrogen atoms, sulfur atoms and silicon atoms is a hydrocarbyl group having a carbon atom substituted by one or more heteroatoms. . Examples thereof include hydrocarbyl groups having groups such as ether groups, glycidyl ether groups, alcohol groups, carboxylic acid groups, ester groups, acrylic groups, trialkoxysilyl groups, silyl groups, and siloxy groups. In addition, the halohydrocarbyl group and the perhalocarbyl group having a heteroatom selected from one or more oxygen atoms, nitrogen atoms, sulfur atoms and silicon atoms, except for the presence or number of substitution with halogen atoms, It is the same as the hydrocarbyl group having a hetero atom selected from the one or more oxygen atoms, nitrogen atoms, sulfur atoms and silicon atoms.

  In the present invention, the “hydrocarbylene group” is the same as the hydrocarbyl group except that the hydrocarbyl group is a monovalent group, whereas the hydrocarbylene group is a divalent group. Similarly, in the present invention, the “halohydrocarbylene group” means a halohydrocarbyl group, except that the halohydrocarbyl group is a monovalent group, whereas the halohydrocarbylene group is a divalent group. It is the same. Similarly, in the present invention, the “perhalocarbylene group” is the same as the perhalocarbyl group except that the perhalocarbyl group is a monovalent group, whereas the perhalocarbylene group is a divalent group. It is.

  In the present invention, the “aralkyl pendant group” refers to a lower alkyl group substituted with an aryl group, such as a benzyl group, a phenylpropyl group, a naphthylmethyl group, or a naltylmethyl group.

  The molar ratio (%) of the structural unit represented by the general formula (1) in the active radiation curable polymer (b-1) is “{the structural unit corresponding to the structural unit represented by the general formula (1). Of the total of the structural units corresponding to the structural unit represented by the general formula (1) + the total number of the structural units corresponding to the structural unit represented by the general formula (3)} × 100 ", 10 to 100%, preferably 20 to 60%, particularly preferably 20 to 50%. When the molar ratio of the structural unit represented by the general formula (1) in the actinic radiation curable polymer (b-1) is within the above range, sufficient crosslinking can be performed and the toughness of the waveguide film can be increased. Can be high.

The actinic radiation curable polymer (b) includes at least one structural unit selected from the structural units represented by the general formula (1) and a structural unit represented by the following formula (4): A polymer copolymerized at random, wherein the molar ratio of the structural unit represented by the general formula (1) is 10 to 100% (hereinafter, such a polymer is referred to as an actinic radiation curable polymer (b-2). ))).
Formula (4):

  The molar ratio (%) of the structural unit represented by the general formula (1) in the active radiation curable polymer (b-2) is “{the structural unit corresponding to the structural unit represented by the general formula (1). Of the total of the structural units corresponding to the structural unit represented by the general formula (1) + the total number of the structural units corresponding to the structural unit represented by the general formula (4)} × 100 ", 10 to 100%, preferably 20 to 60%, particularly preferably 20 to 50%. When the molar ratio of the structural unit represented by the general formula (1) in the actinic radiation curable polymer (b-2) is within the above range, the crosslinking can be sufficiently performed and the toughness of the waveguide film can be increased. Can be high.

The actinic radiation curable polymer (b) is a polymer obtained by polymerizing a structural unit represented by the following general formula (5) (hereinafter, such a polymer is also referred to as an actinic radiation curable polymer (b-3)). ). ^R 1 in the structural unit represented by the following general formula ^{(5), R 2, R} 3 and ^{R 4, R 1, R 2, R} 3 and ^{R 4} in the structural unit represented by the general formula (1) It is the same.
General formula (5):

(In the formula, ^one of R ¹ , R ² , R ³ and R ⁴ is a maleimide group represented by the general formula (2). The rest of R ¹ , R ² , R ³ and R ⁴ is A hydrogen atom; a linear or branched hydrocarbyl group having 1 to 25 carbon atoms; a linear or branched halohydrocarbyl group having 1 to 25 carbon atoms; or a linear or branched group having 1 to 25 carbon atoms Perhalocarbyl group, which may be the same or different.)

  The actinic radiation curable polymer (b) has one or more structural units selected from the structural units represented by the general formula (1) or the structural units represented by the general formula (5). It is an olefin polymerization polymer, and the polymerization ratio of the structural unit represented by the general formula (1) or the structural unit represented by the general formula (5) is 10 to 100 in terms of a polymerization monomer in terms of a molar ratio to the total olefin polymerization monomer. %, Preferably 20-60%, particularly preferably 20-50%. The olefin polymerized polymer is a polymer obtained by using olefins as polymerization monomers and polymerizing the olefins.

  The molecular weight of the actinic radiation curable polymer (b) is not particularly limited, but is preferably 60000 to 150,000 in weight average molecular weight (Mw), particularly preferably 80000 to 120,000.

  The refractive index of the cured product of the actinic radiation curable polymer (b) is preferably 1.54 to 1.60, particularly preferably 1.55 to 1.59. When the refractive index of the cured product of the actinic radiation curable polymer (b) is within the above range, the refractive index can be easily adjusted.

  And the active radiation curable polymer layer preparation process which concerns on the manufacturing method of the optical waveguide of this invention is performed. The actinic radiation curable polymer layer preparation step is a step of preparing the actinic radiation curable polymer (b) layer containing the low molecular weight compound (a).

  The actinic radiation curable polymer (b) layer is formed of the actinic radiation curable polymer (b), and the actinic radiation curable polymer (b) layer contains the low molecular weight compound (a). To do.

The low molecular weight compound (a) is a compound (reactive monomer) that reacts with a maleimide group when irradiated with actinic radiation, and examples thereof include vinyl ethers, thiols, and (meth) acrylates. The vinyl ethers as the low molecular weight compound (a) are compounds having a vinyl ether group (CH ₂ ═CH—O—). The thiols as the low molecular weight compound (a) are compounds having a thiol group (—SH). The (meth) acrylates as the low molecular weight compound (a) have an acrylate group (CH ₂ ═CH—CO—O—) or a methacrylate group (CH ₃ —CH═CH—CO—O—). A compound.

  The low molecular weight compound (a) has a substituent or an element that contributes to changing the refractive index of the cured product of the active radiation curable polymer (b) together with a reactive group that photoreacts with the maleimide group. Examples of substituents or elements that contribute to increasing the refractive index of the cured product of the active radiation curable polymer (b) include substituents such as phenyl groups and aralkyl pendant groups, sulfur, iron, lead, gold , Platinum, silver, copper, chromium, cadmium, mercury, zinc, arsenic, manganese, cobalt, nickel, molybdenum, tungsten, tin, bismuth and the like. Examples of the substituent or element that contributes to lowering the refractive index of the cured product of the actinic radiation curable polymer (b) include a substituent such as a silanol group and an element such as fluorine. In addition, the thiol group (-SH group) in the thiols is a reactive group that photoreacts with the maleimide group, and the sulfur element derived from the thiol group after the thiol group has reacted is the active radiation curable polymer. It functions as an element that increases the refractive index of the cured product (b).

  Since the low molecular weight compound (a) has a lower refractive index and a higher refractive index than the cured product of the active radiation curable polymer (b), the active radiation is included in the low molecular weight compound (a). Those having a lower refractive index than the cured product of the curable polymer (b) are used as the low molecular weight compound (a) in the optical waveguide production method (1) of the present invention, while the low molecular weight compound (a) Among them, those having a higher refractive index than the cured product of the actinic radiation curable polymer (b) are used as the low molecular weight compound (a) in the method (2) for producing an optical waveguide of the present invention. For example, the vinyl ethers as the low molecular weight compound (a) include those having a lower refractive index than those of the cured product of the actinic radiation curable polymer (b) and those having a higher refractive index. Those having a refractive index lower than that of the cured product of the actinic radiation curable polymer (b) are used as the low molecular weight compound (a) in the production method (1) of the optical waveguide of the present invention. Those having a higher refractive index than the cured product of the actinic radiation curable polymer (b) are used as the low molecular weight compound (a) in the optical waveguide production method (2) of the present invention. In addition, the thiols as the low molecular weight compound (a) include those having a refractive index lower than that of the cured product of the active radiation curable polymer (b) and those having a higher refractive index. Those having a lower refractive index than the cured product of the actinic radiation curable polymer (b) are used as the low molecular weight compound (a) in the optical waveguide manufacturing method (1) of the present invention, Those having a higher refractive index than the cured product of the actinic radiation curable polymer (b) are used as the low molecular weight compound (a) in the optical waveguide production method (2) of the present invention. Further, the (meth) acrylates as the low molecular weight compound (a) include those having a lower refractive index and those having a higher refractive index than the cured product of the actinic radiation curable polymer (b). ) Among the acrylates, those having a refractive index lower than that of the cured product of the actinic radiation curable polymer (b) are used as the low molecular weight compound (a) in the optical waveguide production method (1) of the present invention. Among the (meth) acrylates, those having a higher refractive index than the cured product of the actinic radiation curable polymer (b) are used as the low molecular weight compound (a) in the optical waveguide production method (2) of the present invention. Used.

  In the first irradiation step, depending on the type of the low molecular weight compound (a), a polymerization reaction between the low molecular weight compounds (a) occurs due to irradiation with actinic radiation. For example, when the low molecular weight compound (a) is the (meth) acrylate, a polymer obtained by polymerizing two or more of the (meth) acrylates by irradiation with actinic radiation during the first irradiation step. Produces. In such a case, in the first irradiation step, a reaction between the produced polymer of the low molecular weight compound (a) and a maleimide group also occurs. The polymer of the low molecular weight compound (a) produced during the first irradiation step may not react with the maleimide group, and the polymer of the low molecular weight compound (a) After the second irradiation step, the actinic radiation curable polymer (b) is present in the cured product without being bonded to the cured product. In the present invention, the low molecular weight compound ( The polymer of a) may be present.

  The low molecular weight compound (a) is heated or under reduced pressure or under heating and reduced pressure from the actinic radiation curable polymer (b) layer in the unexposed area that has not been irradiated with active radiation in the low molecular weight compound volatilization step. Anything that volatilizes may be used. The molecular weight of the low molecular weight compound (a) is 40 to 800, preferably 60 to 500, particularly preferably 100 to 200.

  The content of the low molecular weight compound (a) in the active radiation curable polymer (b) layer is such that the refractive index of the low molecular weight compound (a) or the refractive index of the cured product of the active radiation curable polymer (b). The amount is appropriately selected depending on how much the amount is changed, but is preferably 2 to 50% by mass, particularly preferably 5 to 30% by mass.

  In the active radiation curable polymer (b) layer, the reactive group that photoreacts with the maleimide group in the low molecular weight compound (a), for example, the vinyl group, thiol group, acrylate group, methacrylate group, etc. The ratio of the number of moles of maleimide groups in the actinic radiation curable polymer (b) (maleimide groups / reactive groups in the low molecular weight compound (a)) is the reactivity of the low molecular weight compound (a) and the core and intermediate layers. Although it is appropriately selected depending on the design policy of how much the difference in refractive index between the clad part and the like is, it is preferably 0.05 to 0.7, particularly preferably 0.1 to 0.3. .

The actinic radiation curable polymer (b) layer can contain a photoreaction accelerator such as a photoradical generator as long as the light propagation loss does not increase in order to promote the photocrosslinking reaction between maleimide groups. . Examples of the photo radical generator include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and the like. Is mentioned.
In addition, the actinic radiation curable polymer (b) layer can contain a photosensitizer as long as the light propagation loss does not increase in order to expand the photosensitive wavelength region of the photocrosslinking reaction. Examples of the photosensitizer include thioxanthone such as 2-chlorothioxanthone, 2-isopropylthioxanthone and 2-chloropropoxythioxanthone, and quinones such as 2,3-dichloro-5,6-dicyanobenzoquinone and anthraquinone.

  Moreover, this actinic radiation curable polymer (b) layer may contain additives, such as a close_contact | adherence adjuvant, antioxidant, and a dissolution promoter, as needed. Examples of the adhesion assistant include vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, trimethoxysilylnorbornene. And silane coupling agents such as triethoxynorbornene and trimethoxysilylethylnorbornene.

  In the actinic radiation curable polymer layer production step, the actinic radiation curable polymer layer is produced on the lower clad.

  The lower clad may be conventionally used and is not particularly limited, but has high transparency, excellent heat resistance and water absorption resistance, and high mechanical strength, and the active radiation curable polymer. What is excellent in adhesiveness with the hardened | cured material of (b) is preferable.

  Examples of such a material for the lower clad include photopolymerizable norbornene resin, photopolymerizable acrylic resin, photopolymerizable methacrylic resin, photopolymerizable epoxy resin, and photopolymerizable oxetane. Resin, photopolymerizable styrene resin, and the like. Among these, photopolymerizable alicyclic epoxy resins are preferable because they are particularly excellent in transparency. These may be used alone or in combination of two or more.

  The lower clad is produced by a conventionally known method. Usually, a varnish in which the material of the lower clad is dissolved is applied on an arbitrary substrate such as a glass substrate, a silicon wafer, etc., the solvent is removed, and the photoclave is applied to the lower clad on the substrate. Make it.

  In the step of preparing the actinic radiation curable polymer layer, as a method for preparing the actinic radiation curable polymer (b) layer on the lower clad, for example, first, the actinic radiation curable polymer (b) and the low radiation curable polymer layer (b) The molecular weight compound (a) is dissolved or dispersed in a solvent to prepare the actinic radiation curable polymer (b) layer preparation varnish, and this varnish is formed on the lower clad with a doctor blade, a circular coater, a spray coater, Examples thereof include a method of coating the active radiation curable polymer (b) layer by coating with a die coater, a comma coater or the like and then volatilizing the solvent from the varnish. In this method, the solvent only needs to have a lower boiling point than the low molecular weight compound (a), and examples thereof include toluene, xylene, and mesitylene. Moreover, this photoreaction accelerator, this photosensitizer, and this additive can be added to this varnish as needed.

  Next, the first irradiation step according to the method for manufacturing an optical waveguide of the present invention is performed. The first irradiation step is a step of irradiating the active radiation curable polymer (b) layer with an active radiation using a pattern-shaped mask.

  In the first irradiation step, the active radiation to be applied to the active radiation curable polymer (b) layer may be any radiation that can cause a photoreaction, and examples thereof include visible light, ultraviolet light, infrared light, and laser light. , Electron beam, X-ray and the like. Of these, ultraviolet rays and laser beams are preferred.

  The mask is for preventing the active radiation curable polymer (b) layer from being irradiated with active radiation. And in the manufacturing method (1) of the optical waveguide of this invention, the exposure part irradiated with the active radiation by this 1st irradiation process turns into an intermediate | middle layer clad part, and the unexposed part which was not irradiated with active radiation is a core Therefore, the pattern shape of the mask is made to be the pattern shape of the core portion. On the other hand, in the optical waveguide manufacturing method (2) of the present invention, the exposed portion irradiated with the active radiation in the first irradiation step becomes the core portion, and the unexposed portion not irradiated with the active radiation is the intermediate layer cladding. Therefore, the pattern shape of the mask is made to be the pattern shape of the intermediate clad portion.

In the first irradiation step, the irradiation amount of the active radiation is appropriately selected. In the first irradiation step, if the irradiation amount is such that the low molecular weight compound (a) reacts with the maleimide group. Good. The purpose of the first irradiation step is to react the low molecular weight compound (a) with a maleimide group of the actinic radiation curable polymer (b) by reacting the low molecular weight compound (a) with a maleimide group. Therefore, in the second irradiation step, the irradiation amount may be smaller than the irradiation amount for curing the active radiation curable polymer (b) by a cross-linking reaction between maleimide groups. For example, when the actinic radiation is ultraviolet, a light source containing 200 to 450 nm, for example, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, or a metal halide lamp is used, and the actinic radiation curable polymer (b) layer is 500 to 2000 mJ / cm. Irradiate ² ultraviolet rays. Moreover, the irradiation amount of actinic radiation can be adjusted with the irradiation intensity and irradiation time of actinic radiation. For example, ultraviolet rays having an irradiation intensity of 10 to 40 mW / cm ² are irradiated for 100 to 300 seconds.

  In the first irradiation step, the low-molecular weight compound (a) or a polymer of the low-molecular weight compound (a) reacts with a maleimide group, whereby the active radiation curing of the exposed portion irradiated with active radiation. The low molecular weight compound (a) or a polymer of the low molecular weight compound (a) is bonded and firmly held in the functional polymer (b) layer in the structure after photoreaction with the maleimide group.

  Next, the low molecular weight compound volatilization step according to the method for manufacturing an optical waveguide of the present invention is performed. In the low molecular weight compound volatilization step, the low molecular weight compound (a) is volatilized from an unexposed portion of the actinic radiation curable polymer (b) layer that has not been irradiated with active radiation under heating or reduced pressure. . The term “under heating or under reduced pressure” refers to heating the active radiation curable polymer (b) layer, placing it under a reduced pressure, or reducing the pressure while heating.

  In the low molecular weight compound volatilization step, the heating temperature or the degree of reduced pressure is such that the content of the low molecular weight compound (a) in the actinic radiation curable polymer (b) layer in the unexposed area is not more than a predetermined content. As described above, the heating temperature is preferably 50 to 180 ° C., particularly preferably 80 to 150 ° C., depending on the type of the active radiation curable polymer (b) and the low molecular weight compound (a). The degree of vacuum is usually 0.1 to 0.5 kPa, preferably 0.1 to 0.3 kPa. Further, the heating time or the reduced pressure time is appropriately selected so that the content of the low molecular weight compound (a) in the actinic radiation curable polymer (b) layer in the unexposed part is not more than a predetermined content. The

  In the actinic radiation curable polymer (b) layer in the unexposed area that has not been irradiated with actinic radiation, since the low molecular weight compound (a) is not bonded to a maleimide group, under heating or under reduced pressure, Volatilizes from the active radiation curable polymer (b) layer. Therefore, by performing the low molecular weight compound volatilization step, the active radiation curable polymer (b) layer prepared in the active radiation curable polymer layer preparation step is added to the active radiation curable polymer layer (b) layer. A portion containing the low molecular weight compound (a) in the same amount as the content and a portion not containing the low molecular weight compound (a) or having a reduced content can be formed.

  Next, the second irradiation step according to the method for manufacturing an optical waveguide of the present invention is performed. In the second irradiation step, the actinic radiation curable polymer (b) layer is irradiated with actinic radiation to cause a crosslinking reaction in the maleimide group of the entire actinic radiation curable polymer (b) layer. Is a step of curing the actinic radiation curable polymer (b).

In the second irradiation step, the active radiation applied to the active radiation curable polymer (b) layer is the same as the active radiation applied to the active radiation curable polymer (b) layer in the first irradiation step. It is. In the second irradiation step, the irradiation amount of the actinic radiation is appropriately selected, the maleimide groups of the actinic radiation curable polymer (b) undergo a crosslinking reaction, and the actinic radiation curable polymer (b) is irradiated with light. A dose that cures is selected. For example, when the actinic radiation is ultraviolet, a light source including 200 to 450 nm, for example, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, or a metal halide lamp is used, and the actinic radiation curable polymer (b) layer is coated with 2000 to 10,000 mJ / cm. Irradiate ² ultraviolet rays. For example, ultraviolet rays having an irradiation intensity of 20 to 40 mW / cm ² are irradiated for 100 to 300 seconds.

  And by performing this 2nd irradiation process, this actinic radiation curable polymer (b) layer becomes a hardened | cured material layer of this actinic radiation curable polymer (b). Here, in the optical waveguide manufacturing method (1) of the present invention, the exposed portion of the cured product layer of the actinic radiation curable polymer (b) acts as a compound that lowers the refractive index of the cured product. Since the low molecular weight compound (a) is contained in a structure after reaction with the maleimide group, the exposed portion has a lower refractive index than the unexposed portion. Therefore, in the optical waveguide manufacturing method (1) of the present invention, the exposed portion becomes the intermediate layer cladding portion, and the unexposed portion becomes the core portion. On the other hand, in the method (2) for producing an optical waveguide of the present invention, the exposed portion of the cured product layer of the actinic radiation curable polymer (b) acts as a compound that increases the refractive index of the cured product. Since the low molecular weight compound (a) is contained in the structure after reaction with the maleimide group, the exposed portion has a higher refractive index than the unexposed portion. Therefore, in the optical waveguide manufacturing method (2) of the present invention, the exposed portion becomes the core portion, and the unexposed portion becomes the intermediate layer cladding portion.

  Next, an upper cladding is produced on the cured layer of the actinic radiation curable polymer (b) to obtain an optical waveguide.

  The upper clad may be conventionally used and is not particularly limited. The upper clad and the lower clad are formed on the cured layer of the actinic radiation curable polymer (b), whereas the lower clad is formed on the substrate or the like. The material of the upper clad, the production method, and the like are the same as those of the lower clad, although they are different from each other.

  In the method for producing an optical waveguide of the present invention, by appropriately selecting the type of the active radiation curable polymer (b), the type of the low molecular weight compound (a), and the content of the low molecular weight compound (a), It is possible to adjust the refractive index difference of the core portion, the refractive index of the intermediate layer cladding portion, and the refractive index of the core portion and the intermediate layer cladding portion. The difference in refractive index between the core portion and the intermediate clad portion is not particularly limited, but is preferably 0.3 to 4.0%, particularly preferably 0.5 to 2.5%.

  In the method for producing an optical waveguide of the present invention, the type of the active radiation curable polymer (b), the type of the low molecular weight compound (a), and the content of the low molecular weight compound (a), that is, after curing The material of the lower clad and the upper clad may be appropriately selected depending on the refractive indexes of the core and the intermediate clad.

  In the method for producing an optical waveguide according to the present invention, it is not necessary to perform a developing step of removing a non-exposed portion with a developer to obtain a pattern of a core portion. Therefore, the optical waveguide manufacturing method of the present invention is a simpler method than the conventional optical waveguide manufacturing method that requires a development step.

  Moreover, in the manufacturing method of the optical waveguide of this invention, the difference of the refractive index of a core part and an intermediate | middle layer clad part can be adjusted with the kind or content of this low molecular weight compound (a). Therefore, as compared with the conventional method of adjusting the difference in refractive index between the core portion and the intermediate layer cladding portion only by the polymer material constituting the core portion and the intermediate layer cladding portion, the method for manufacturing the optical waveguide of the present invention It is easy to adjust the difference in refractive index between the core portion and the intermediate layer cladding portion.

  Furthermore, in the method for manufacturing an optical waveguide according to the present invention, the core portion and the clad portion are separately formed by the first irradiation step. In general, the low molecular weight compound (a) and maleimide by irradiation with actinic radiation are compared with the reaction between maleimide groups by irradiation with actinic radiation, that is, the crosslinking reaction of the actinic radiation curable polymer (b). Irradiation of active radiation in the first irradiation step of the present invention compared to irradiation of actinic radiation to an actinic radiation curable polymer in a conventional optical waveguide manufacturing method because reaction with a group is more likely to occur The amount can be reduced. Therefore, in the method for manufacturing an optical waveguide according to the present invention, a phenomenon such as a dark reaction that is induced when an ultraviolet ray is excessively irradiated with a chemically amplified resist can be prevented, so that a clear core pattern can be obtained.

  The method for producing a cured product of an actinic radiation curable polymer in the method for producing an optical waveguide of the present invention is suitable for providing portions having different refractive indexes in one layer, for example, holography, polymer optical fiber It can also be applied as a manufacturing method for microlenses, prisms and the like.

That is, the method for producing a cured product of the actinic radiation curable polymer of the present invention includes the actinic radiation curable polymer (b) layer containing the low molecular weight compound (a), that is, the actinic radiation curable polymer (b). An actinic radiation curable polymer layer producing step for producing an actinic radiation curable polymer (b) layer containing the low molecular weight compound (a), and
A first irradiation step of irradiating the active radiation curable polymer (b) layer with a mask having a pattern shape and irradiating with active radiation;
A low molecular weight compound volatilization step for volatilizing the low molecular weight compound (a) from an unexposed portion of the actinic radiation curable polymer (b) layer that has not been irradiated with actinic radiation under heating or reduced pressure;
A second irradiation step of irradiating the active radiation curable polymer (b) layer with active radiation;
Is a method for producing a cured product of an actinic radiation curable polymer.

  Examples of the present invention will be described below in comparison with comparative examples to demonstrate the effects. In addition, these Examples show one embodiment of this invention, and this invention is not limited to these.

Example 1
(1) Synthesis of actinic radiation curable polymer 8.4 g (35.9 mmol) of decylnorbornene (DeNB), phenylethyl in a glove box whose moisture and oxygen concentrations were both controlled to 1 ppm or less and filled with dry nitrogen Weigh 5.3 g (27.0 mmol) of norbornene (PENB) and 6.2 g (27.0 mmol) of dimethylmaleimide norbornene (DMMINB) into a 500 mL vial, add 60 g of dehydrated toluene and 11 g of ethyl acetate, and add a silicon sealer. Covered and sealed the top.
Next, 1.74 g (3.6 mmol) of Ni catalyst represented by the following chemical formula (6) and 10 mL of dehydrated toluene are weighed in a 100 mL vial, put a stirrer chip and sealed, and the catalyst is thoroughly stirred to completely Dissolved in.
When 1 mL of the Ni catalyst solution represented by the following chemical formula (6) is accurately weighed with a syringe, and quantitatively injected into the vial bottle in which the above three types of norbornene are dissolved and stirred at room temperature for 1 hour, a marked increase in viscosity occurs. Was confirmed. At this point, the stopper was removed, 60 g of tetrahydrofuran (THF) was added, and the mixture was stirred to obtain a reaction solution.
In a 100 mL beaker, 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (concentration 30%) and 30 g of ion-exchanged water were added and stirred to prepare an aqueous solution of peracetic acid on the spot. Next, the total amount of this aqueous solution was added to the above reaction solution and stirred for 12 hours to reduce Ni.
Next, the treated reaction solution was transferred to a separatory funnel, the lower aqueous layer was removed, and then 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. The aqueous layer was removed after standing and completely separating the two layers. After repeating this water washing process three times in total, the oil layer was dropped into a large excess of acetone to reprecipitate the polymer produced, separated from the filtrate by filtration, and then in a vacuum dryer set at 60 ° C. By performing heat drying for 12 hours, actinic radiation curable polymer # 1 having a dimethylmaleimide group (a structural unit represented by the following formula (7-1), a structural unit represented by the following formula (7-2), A polymer in which a structural unit represented by the following formula (7-3) was randomly copolymerized was obtained. The molecular weight distribution of the polymer # 1 is Mw = 100,000, Mn = 40,000 by GPC measurement, and the molar ratio of each structural unit in the polymer # 1 is decylnorbornene structural unit (the following formula (7-1) )) Is 40 mol%, phenylethylnorbornene structural unit (the following formula (7-2)) is 30 mol%, dimethylmaleimide norbornene structural unit (the following formula (7-3)) is 30 mol%, and the refractive index is 1 according to Metricon. .56 (measurement wavelength; 633 nm).
Chemical formula (6):

Formulas (7-1) to (7-3):

  In the above formulas (7-1) to (7-3), the numbers on the lower right of the parentheses of each structural unit represent mol% of each structural unit in the polymer, and each structural unit is continuous. It does not represent what you are doing.

(2) Preparation of actinic radiation curable polymer layer forming varnish V1 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, 40 g of mesitylene, 0.01 g of antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyl Add 0.1 g of acrylate monomer (Osaka Organic Chemical Co., Ltd. V # 155, CAS # 3066-71-5, molecular weight 154, boiling point 200 ° C./101 kPa) and uniformly dissolve, then filter through 0.2 μm PTFE filter To obtain a clean varnish V1 for forming an active radiation curable polymer layer.
At this time, the ratio of the number of moles of maleimide groups to the number of moles of reactive groups (acrylate groups) of the cyclohexyl acrylate monomer was 0.05.

(3) Production of lower layer clad A photosensitive norbornene resin composition (Avatrel 2000P varnish) was uniformly applied on a silicon wafer with a doctor blade, and then placed in a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, the entire coated surface was irradiated with 100 mJ of ultraviolet light and heated in a dryer at 120 ° C. for 1 hour to cure the coating film to form a lower clad. The formed lower clad had a thickness of 20 μm, was colorless and transparent, and had a refractive index of 1.52 (measurement wavelength: 633 nm).

(4) Formation of core part and intermediate | middle layer clad part After apply | coating the actinic radiation curable polymer layer forming varnish V1 uniformly on the said lower layer clad with a doctor blade, it was thrown into a 45 degreeC drying machine for 15 minutes. After completely removing the solvent, a photomask was pressure-bonded and irradiated with ultraviolet rays of 2000 mJ / cm ² (irradiation with ultraviolet rays having an irradiation intensity of 20 mW / cm ² for 100 seconds). The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating.
Next, the entire surface of the actinic radiation curable polymer layer was irradiated with ultraviolet rays at 5000 mJ / cm ² (irradiated with ultraviolet rays having an irradiation intensity of 20 mW / cm ² for 250 seconds) and heated at 150 ° C. for 1 hour to form an active radiation curable polymer layer. Curing was performed to form a core portion and an intermediate layer cladding portion having a thickness of 50 μm. At this time, the core part was colorless and transparent, and the refractive index was 1.55, and the intermediate layer cladding part was colorless and transparent, and the refractive index was 1.54.

(5) Formation of upper layer clad A dry film in which Avatrel 2000P was laminated in advance so as to have a dry thickness of 20 μm on a polyethersulfone (PES) film was bonded to the core part and the intermediate layer clad part, and set to 140 ° C. After being put into the vacuum laminator and thermocompression bonded, the entire surface was irradiated with ultraviolet rays at 100 mJ and heated in a dryer at 120 ° C. for 1 hour to cure Avatrel 2000P to form an upper clad to obtain an optical waveguide . At this time, the upper clad was colorless and transparent, and the refractive index was 1.52.

(6) Loss Evaluation of Optical Waveguide Light emitted from an 850 nm VCSEL (surface emitting laser) was introduced into the optical waveguide via a 50 μmφ optical fiber, and received by a 200 μmφ optical fiber to measure the light intensity. In addition, the cutback method was employ | adopted for the measurement. When the waveguide length is plotted on the horizontal axis and the insertion loss is plotted on the vertical axis, the measured values are neatly arranged on a straight line, and the propagation loss can be calculated as 0.03 dB / cm from the inclination.

(Example 2)
(1) Synthesis of actinic radiation curable polymer Using known methods (for example, Japanese Patent Application Laid-Open No. 2003-252963), ring-opening metathesis polymerization of DMMINB monomer is performed, and actinic radiation curable polymer # 2 having a dimethylmaleimide group ( A polymer in which the structural unit represented by the following formula (8) was polymerized was obtained.
Formula (8):

  The molecular weight distribution of Polymer # 2 was Mw = 80,000, Mn = 30,000 by GPC measurement, and the refractive index was 1.57 (measurement wavelength: 633 nm) by Metricon.

(2) Preparation of varnish V2 for forming actinic radiation curable polymer layer 10 g of the purified polymer # 2 was weighed into a 100 mL glass container, 40 g of mesitylene, 0.01 g of an antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyl Add 0.1 g of acrylate monomer (Osaka Organic Chemical Co., Ltd. V # 155, CAS # 3066-71-5, molecular weight 154, boiling point 200 ° C./101 kPa) and uniformly dissolve, then filter through 0.2 μm PTFE filter To obtain a clean varnish V2 for forming an active radiation curable polymer layer.
At this time, the ratio of the number of moles of maleimide groups to the number of moles of reactive groups (acrylate groups) of the cyclohexyl acrylate monomer was 0.2.

(3) Preparation of lower clad It carried out similarly to Example 1.

(4) Formation of core part and intermediate | middle layer clad part After apply | coating the active radiation curable polymer layer forming varnish V2 on the said lower layer clad with a doctor blade uniformly, it injected | threw-in to 45 degreeC drying machine for 15 minutes. After completely removing the solvent, a photomask was pressure-bonded and irradiated with ultraviolet rays of 2000 mJ / cm ² (irradiation with ultraviolet rays having an irradiation intensity of 20 mW / cm ² for 100 seconds). The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating.
Next, the entire surface of the actinic radiation curable polymer layer was irradiated with ultraviolet rays at 5000 mJ / cm ² (irradiated with ultraviolet rays having an irradiation intensity of 20 mW / cm ² for 250 seconds) and heated at 150 ° C. for 1 hour to form an active radiation curable polymer layer. Curing was performed to form a core portion and an intermediate layer cladding portion having a thickness of 50 μm. At this time, the core part was colorless and transparent, and the refractive index was 1.56, and the intermediate layer cladding part was colorless and transparent, and the refractive index was 1.55.

(5) Formation of upper clad It carried out by the method similar to Example 1, and obtained the optical waveguide.

(6) Optical waveguide loss evaluation When the same method as in Example 1 was used, the propagation loss could be calculated as 0.04 dB / cm.

(Example 3)
(1) Synthesis of actinic radiation curable polymer In the same manner as in Example 1, actinic radiation curable polymer # 1 was obtained.

(2) Preparation of varnish V3 for forming actinic radiation curable polymer layer 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, an antioxidant Irganox 1076 (manufactured by Ciba Geigy) 0.01 g, 2 Add 0.05 g of ethylhexyl- (3-mercaptopropionate) (manufactured by Maruzen Petrochemical Co., Ltd., CAS # 50448-95-8, molecular weight 218.36, boiling point 145 ° C./5.3 kPa), and dissolve uniformly. Then, filtration was performed with a 0.2 μm PTFE filter to obtain a clean actinic radiation curable polymer layer forming varnish V3.
At this time, the ratio of the number of moles of the maleimide group to the number of moles of the reactive group (mercapto group (—SH)) of 2-ethylhexyl- (3-mercaptopropionate) was 0.13.

(3) Preparation of lower clad It carried out similarly to Example 1.

(4) Formation of core part and intermediate | middle layer clad part After apply | coating varnish V3 for actinic radiation curable polymer layer formation uniformly with a doctor blade on the said lower layer clad, it injected | thrown-in to the 45 degreeC drying machine for 15 minutes. After completely removing the solvent, a photomask was pressure-bonded and irradiated with ultraviolet rays at 1000 mJ / cm ² (irradiation with ultraviolet rays having an irradiation intensity of 10 mW / cm ² for 100 seconds). The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 150 ° C. for 1 hour. It was confirmed that a very clear waveguide pattern appeared after heating.
Next, the entire surface of the actinic radiation curable polymer layer was irradiated with ultraviolet rays at 6000 mJ / cm ² (irradiated with ultraviolet rays having an irradiation intensity of 25 mW / cm ² for 240 seconds), and heated at 150 ° C. for 1 hour to Curing was performed to form a core portion and an intermediate layer cladding portion having a thickness of 50 μm. At this time, the core part was colorless and transparent, and the refractive index was 1.55, and the intermediate layer cladding part was colorless and transparent, and the refractive index was 1.54.

(5) Formation of upper layer clad It carried out similarly to Example 1 and obtained the optical waveguide.

(6) Loss evaluation of optical waveguide When performed in the same manner as in Example 1, the propagation loss was calculated to be 0.03 dB / cm.

(Comparative Example 1)
(1) Synthesis of actinic radiation curable polymer 6.7 g (28.7 mmol) of decylnorbornene (DeNB), phenylethyl in a glove box whose water and oxygen concentrations were both controlled to 1 ppm or less and filled with dry nitrogen 13.3 g (66.9 mmol) of norbornene (PENB) was weighed into a 500 mL vial, 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the top was sealed with a silicon sealer.
Next, 1.85 g (3.8 mmol) of the Ni catalyst represented by the chemical formula (6) and 10 mL of dehydrated toluene are weighed in a 100 mL vial, put a stirrer chip and sealed, and the catalyst is thoroughly stirred to completely Dissolved in.
When 1 mL of the Ni catalyst solution represented by the chemical formula (6) is accurately weighed with a syringe, and quantitatively injected into the vial bottle in which the two types of norbornene are dissolved and stirred at room temperature for 1 hour, a marked increase in viscosity occurs. Was confirmed. At this point, the stopper was removed, and 60 g of THF was added and stirred to obtain a reaction solution.
In a 100 mL beaker, 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (concentration 30%) and 30 g of ion-exchanged water were added and stirred to prepare an aqueous solution of peracetic acid on the spot. Next, the total amount of this aqueous solution was added to the above reaction solution and stirred for 12 hours to reduce Ni.
Next, the treated reaction solution was transferred to a separatory funnel, the lower aqueous layer was removed, and then 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. The aqueous layer was removed after standing and completely separating the two layers. After repeating this water washing process three times in total, the oil layer was dropped into a large excess of acetone to reprecipitate the polymer produced, separated from the filtrate by filtration, and then in a vacuum dryer set at 60 ° C. By conducting heat drying for 12 hours, actinic radiation curable polymer # 3 (a structural unit represented by the following formula (9-1) and a structural unit represented by the following formula (9-2) are randomly copolymerized. Polymer). The molecular weight distribution of polymer # 3 is Mw = 120,000, Mn = 50,000 by GPC measurement, and the molar ratio of each structural unit in polymer # 3 is decylnorbornene structural unit (following formula (9-1) ) Was 30 mol%, phenylethyl norbornene structural unit (the following formula (9-2)) was 70 mol%, and the refractive index was 1.55 (measurement wavelength: 633 nm) by metricon.
Formulas (9-1) to (9-2):

  In the above formulas (9-1) to (9-2), the numbers on the lower right of the parentheses of each structural unit represent mol% of each structural unit in the polymer, and each structural unit is continuous. It does not represent what you are doing.

(2) Preparation of varnish V4 for forming actinic radiation curable polymer layer 10 g of the purified polymer # 3 was weighed into a 100 mL glass container, 40 g of mesitylene, 0.01 g of an antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexyl Acrylate monomer (Osaka Organic Chemical Industry V # 155, CAS # 3066-71-5, molecular weight 154, boiling point 200 ° C./101 kPa) 1 g, radical generator Icargacure 651 (Nagase Sangyo, CAS # 24650-42-8) 0.01 g was added and uniformly dissolved, followed by filtration with a 0.2 μm PTFE filter to obtain a clean varnish V4 for forming an active radiation curable polymer layer.

(3) Production of lower clad It was carried out in the same manner as in Example 1.

(4) Formation of core part and intermediate | middle layer clad part After apply | coating the active radiation curable polymer layer forming varnish V4 on the said lower layer clad with a doctor blade uniformly, it injected | threw-in to 45 degreeC drying machine for 15 minutes. After completely removing the solvent, a photomask was pressed and irradiated with ultraviolet rays at 2000 mJ / cm ² . The mask was removed, and heating was performed in three stages: 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 200 ° C. for 1 hour. After heating, the waveguide pattern was only slightly observed.
Next, the entire surface of the actinic radiation curable polymer layer was irradiated with ultraviolet rays at 5000 mJ / cm ² and heated at 150 ° C. for 1 hour to obtain a core portion and an intermediate layer clad having a thickness of 50 μm. At this time, the core part was colorless and transparent, and the refractive index was 1.550, and the intermediate layer cladding part was colorless and transparent, and the refractive index was 1.547.

(5) Formation of upper layer clad It carried out similarly to Example 1 and obtained the optical waveguide.

(6) Loss evaluation of optical waveguide When performed in the same manner as in Example 1, the propagation loss was 5 dB / cm.

(Comparative Example 2)
(1) Synthesis of actinic radiation curable polymer In the same manner as in Example 1, actinic radiation curable polymer # 1 was obtained.

(2) Preparation of varnish V5 for forming actinic radiation curable polymer layer 10 g of the purified polymer # 1 was weighed into a 100 mL glass container, and 40 g of mesitylene, 0.01 g of antioxidant Irganox 1076 (manufactured by Ciba Geigy), cyclohexane After adding 1 g of (CAS # 110-82-7) and dissolving it uniformly, it was filtered through a 0.2 μm PTFE filter to obtain clean actinic radiation curable polymer layer forming varnish V5.

(3) Preparation of lower clad It carried out similarly to Example 1.

(4) Formation of Intermediate Cured Product Layer After the actinic radiation curable polymer layer forming varnish V5 was uniformly applied on the lower clad by a doctor blade, it was put into a dryer at 45 ° C. for 15 minutes. After completely removing the solvent, a photomask was pressed and irradiated with ultraviolet rays at 2000 mJ / cm ² . The mask was removed, and heating was performed in three stages in a dryer at 45 ° C. for 30 minutes, 85 ° C. for 30 minutes, and 120 ° C. for 1 hour. After heating, no waveguide pattern was observed.
Next, the entire surface of the actinic radiation curable polymer layer is irradiated with ultraviolet rays at 5000 mJ / cm ² and heated at 150 ° C. for 1 hour to cure the actinic radiation curable polymer layer to form a cured product layer having a thickness of 50 μm. It was.

(5) Formation of upper layer clad It carried out similarly to Example 1 and obtained the optical waveguide.

(6) Evaluation of optical waveguide loss Measurement was not performed because the waveguide structure could not be confirmed.

It is typical sectional drawing (1) which shows the form example of the manufacturing method (1) of the optical waveguide of this invention. It is typical sectional drawing (2) which shows the example of a manufacturing method (1) of the optical waveguide of this invention. It is typical sectional drawing (3) which shows the example of a manufacturing method (1) of the optical waveguide of this invention. It is typical sectional drawing (4) which shows the form example of the manufacturing method (1) of the optical waveguide of this invention. It is typical sectional drawing (5) which shows the form example of the manufacturing method (1) of the optical waveguide of this invention. It is typical sectional drawing (6) which shows the example of a manufacturing method (1) of the optical waveguide of this invention. It is typical sectional drawing (1) which shows the formation process of the optical waveguide from the polymer material using the conventional photocuring method. It is typical sectional drawing (2) which shows the formation process of the optical waveguide from the polymer material using the conventional photocuring method. It is typical sectional drawing (3) which shows the formation process of the optical waveguide from the polymer material using the conventional photocuring method. It is typical sectional drawing (4) which shows the formation process of the optical waveguide from the polymer material using the conventional photocuring method. It is typical sectional drawing (5) which shows the formation process of the optical waveguide from the polymer material using the conventional photocuring method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 31 Lower clad 2 Active radiation curable polymer layer 3, 33 Photomask 4, 34 Ultraviolet light 5, 36 Unexposed part 6, 35 Exposed part 7 Low molecular weight compound removal unexposed part 8 Intermediate layer clad part 9, 37 Core part DESCRIPTION OF SYMBOLS 10, 39 Upper layer clad 11 Hardened | cured material layer 20 of active radiation curable polymer Optical waveguide 32 Polymer layer 38 for cores Polymer layer for upper layer clads

  According to the present invention, an optical waveguide can be manufactured by a simple method. In addition, the refractive index of the core part and the clad part can be easily adjusted.

Claims (7)

An actinic radiation curable polymer layer production step for producing an actinic radiation curable polymer layer having a maleimide group containing a low molecular weight compound that reacts with the maleimide group by irradiation with actinic radiation;
A first irradiation step of irradiating the active radiation curable polymer layer with a pattern-shaped mask and irradiating with active radiation;
A low molecular weight compound volatilization step for volatilizing the low molecular weight compound from an unexposed portion of the active radiation curable polymer layer that has not been irradiated with the active radiation under heating or reduced pressure;
A second irradiation step of irradiating the entire actinic radiation curable polymer layer with actinic radiation;
Have
Active radiation curable polymer having the maleimide group, Ri polymer der having a maleimide group as and side chains having a cyclohexane skeleton or a cyclopentane skeleton as all or part of the backbone,
The low molecular weight compound is a low molecular weight compound having a lower refractive index than the cured product of the active radiation curable polymer, or a low molecular weight compound having a higher refractive index than the cured product of the active radiation curable polymer. about,
An optical waveguide manufacturing method characterized by the above. The active radiation curable polymer having a maleimide group is an olefin polymer having one or more structural units selected from structural units represented by the following general formula (1) or a structural unit represented by the following general formula (5): The polymerization ratio of the structural unit represented by the following general formula (1) or the structural unit represented by the following general formula (5) is 10 to 100% in terms of a polymerization monomer in terms of a molar ratio to the total olefin polymerization monomer. about,
The method of manufacturing an optical waveguide according to claim 1.
General formula (1):

(In the formula, _{X, -CH 2 -, - CH 2} -CH 2 - or -O- .m, among ^{.R 1, R 2,} R ³ and ^{R 4} is an integer from 0 to 5 Is one of the following general formula (2):

[Wherein, A represents a methylene group, a linear or branched hydrocarbylene group having 2 to 6 carbon atoms, a halohydrocarbylene group or a perhalocarbylene group, or a substituted or unsubstituted carbon number of 5 -12 cyclic or polycyclic hydrocarbylene groups, halohydrocarbylene groups or perhalocarbylene groups. R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms, and may be the same or different, and R ⁵ and R ⁶ may form a ring having 3 to 8 carbon atoms. . ]
Is a maleimide group represented by: The rest of R ¹ , R ² , R ³ and R ⁴ is a hydrogen atom, a linear or branched C 1-25 hydrocarbyl group, halohydrocarbyl group or perhalocarbyl group, which may be the same or different. Also good. )
General formula (5):

(In the formula, ^one of R ¹ , R ² , R ³ and R ⁴ is represented by the following general formula (2):

[Wherein, A represents a methylene group, a linear or branched hydrocarbylene group having 2 to 6 carbon atoms, a halohydrocarbylene group or a perhalocarbylene group, or a substituted or unsubstituted carbon number of 5 -12 cyclic or polycyclic hydrocarbylene groups, halohydrocarbylene groups or perhalocarbylene groups. R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms, and may be the same or different, and R ⁵ and R ⁶ may form a ring having 3 to 8 carbon atoms. . ]
Is a maleimide group represented by: The rest of R ¹ , R ² , R ³ and R ⁴ is a hydrogen atom, a linear or branched C 1-25 hydrocarbyl group, halohydrocarbyl group or perhalocarbyl group, which may be the same or different. Also good. ) The active radiation curable polymer having a maleimide group is selected from one or more structural units selected from structural units represented by the following general formula (1) and a structural unit represented by the following general formula (3): The one or more kinds of structural units are randomly copolymerized polymers, and the molar ratio of the structural units represented by the following general formula (1) is 10 to 100%. Manufacturing method of optical waveguide.
General formula (1):

(In the formula, _{X, -CH 2 -, - CH 2} -CH 2 - or -O- .m, among ^{.R 1, R 2,} R ³ and ^{R 4} is an integer from 0 to 5 Is one of the following general formula (2):

[Wherein, A represents a methylene group, a linear or branched hydrocarbylene group having 2 to 6 carbon atoms, a halohydrocarbylene group or a perhalocarbylene group, or a substituted or unsubstituted carbon number of 5 -12 cyclic or polycyclic hydrocarbylene groups, halohydrocarbylene groups or perhalocarbylene groups. R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms, and may be the same or different, and R ⁵ and R ⁶ may form a ring having 3 to 8 carbon atoms. . ]
Is a maleimide group represented by: The rest of R ¹ , R ² , R ³ and R ⁴ is a hydrogen atom, a linear or branched hydrocarbyl group having 1 to 25 carbon atoms, a halohydrocarbyl group or a perhalocarbyl group, which may be the same or different. Also good. )
General formula (3):

(Wherein, Y _{is, -CH 2 -, - CH 2} -CH 2 - or -O- .n is at least ^{.R 7, R 8,} R ⁹ and ^{R 10} is an integer from 0 to 5 One is a linear, branched or cyclic C1-C25 hydrocarbyl group, halohydrocarbyl group having a heteroatom selected from one or more oxygen atoms, nitrogen atoms, sulfur atoms and silicon atoms, perhalocarbyl group, an aryl group or an aralkyl pendent group or a linear, branched or cyclic hydrocarbyl group having 1 to 25 carbon atoms, halohydrocarbyl group, perhalocarbyl group, .R 7 is an aryl group or an aralkyl pendent ^radical, R ⁸ , the rest of R ⁹ and R ¹⁰ are hydrogen atoms.) The active radiation curable polymer having a maleimide group is randomly selected from at least one structural unit selected from structural units represented by the following general formula (1) and structural units represented by the following formula (4): The method for producing an optical waveguide according to claim 1, wherein the molar ratio of the structural unit represented by the following general formula (1) is 10 to 100%.
General formula (1):

(In the formula, _{X, -CH 2 -, - CH 2} -CH 2 - or -O- .m, among ^{.R 1, R 2,} R ³ and ^{R 4} is an integer from 0 to 5 Is one of the following general formula (2):

[Wherein, A represents a methylene group, a linear or branched hydrocarbylene group having 2 to 6 carbon atoms, a halohydrocarbylene group or a perhalocarbylene group, or a substituted or unsubstituted carbon number of 5 -12 cyclic or polycyclic hydrocarbylene groups, halohydrocarbylene groups or perhalocarbylene groups. R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms, and may be the same or different, and R ⁵ and R ⁶ may form a ring having 3 to 8 carbon atoms. . ]
Is a maleimide group represented by: The rest of R ¹ , R ² , R ³ and R ⁴ is a hydrogen atom, a linear or branched C 1-25 hydrocarbyl group, halohydrocarbyl group or perhalocarbyl group, which may be the same or different. Also good. )
Formula (4):
The method for producing an optical waveguide according to claim 1, wherein the active radiation curable polymer having a maleimide group is a polymer in which a structural unit represented by the following general formula (5) is polymerized.
General formula (5):

(In the formula, ^one of R ¹ , R ² , R ³ and R ⁴ is represented by the following general formula (2):

[Wherein, A represents a methylene group, a linear or branched hydrocarbylene group having 2 to 6 carbon atoms, a halohydrocarbylene group or a perhalocarbylene group, or a substituted or unsubstituted carbon number of 5 -12 cyclic or polycyclic hydrocarbylene groups, halohydrocarbylene groups or perhalocarbylene groups. R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms, and may be the same or different, and R ⁵ and R ⁶ may form a ring having 3 to 8 carbon atoms. . ]
Is a maleimide group represented by: The rest of R ¹ , R ² , R ³ and R ⁴ is a hydrogen atom, a linear or branched C 1-25 hydrocarbyl group, halohydrocarbyl group or perhalocarbyl group, which may be the same or different. Also good. )   The method for producing an optical waveguide according to any one of claims 1 to 5, wherein the low molecular weight compound is vinyl ethers, thiols or (meth) acrylates. An actinic radiation curable polymer layer production step for producing an actinic radiation curable polymer layer having a maleimide group containing a low molecular weight compound that reacts with the maleimide group by irradiation with actinic radiation;
A first irradiation step of irradiating the active radiation curable polymer layer with a pattern-shaped mask and irradiating with active radiation;
A low molecular weight compound volatilization step for volatilizing the low molecular weight compound from an unexposed portion of the active radiation curable polymer layer that has not been irradiated with the active radiation under heating or reduced pressure;
A second irradiation step of irradiating the entire actinic radiation curable polymer layer with actinic radiation;
Have
Active radiation curable polymer having the maleimide group, Ri polymer der having a maleimide group as and side chains having a cyclohexane skeleton or a cyclopentane skeleton as all or part of the backbone,
The low molecular weight compound is a low molecular weight compound having a lower refractive index than the cured product of the active radiation curable polymer, or a low molecular weight compound having a higher refractive index than the cured product of the active radiation curable polymer. about,
A method for producing a cured product of an actinic radiation curable polymer characterized by the following.