JP2014191052A - Method of manufacturing optical waveguide, and optical waveguide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an optical waveguide that improves the liquid (water) removal from a surface of a patterned cladding layer of the optical waveguide without reducing the productivity and inhibits a watermark from remaining, and to provide an optical waveguide having high visibility of a core pattern.SOLUTION: The method of manufacturing an optical waveguide that includes a cladding layer and a core pattern buried in the cladding layer includes the steps of: impregnating a patterned cladding layer with bivalent or more metal ions or exposing the cladding layer; developing the cladding layer with an alkaline developer; and cleaning the developed and patterned cladding layer with an acid solution.

Description

  The present invention relates to an optical waveguide manufacturing method and an optical waveguide.

  With the increase in information capacity, development of an optical interconnection technology that uses optical signals not only for communication fields such as trunk lines and access systems but also for information processing in routers and servers is underway. In particular, as an optical transmission path for using light for short-distance signal transmission between boards in a router or a server device, optical fibers that have a higher degree of freedom of wiring and can be densified than optical fibers. It is desirable to use a waveguide. Among them, an optical waveguide using a polymer material excellent in processability and economy is promising.

  As one of methods for manufacturing an optical waveguide simply and with high accuracy, a method of forming a core pattern through which an optical signal propagates by exposure and development is known. Here, the exposure process is a step of insolubilizing the photosensitive resin in the light irradiation portion by three-dimensional crosslinking, and the development process is a step of dissolving and removing the photosensitive resin in the unexposed portion, that is, the unreacted portion in the developer. is there.

Conventionally, a method using an organic solvent as a developer is known (see, for example, Patent Document 1). However, a method of developing using an alkaline developer has also been proposed from the viewpoint of safety of development process and environmental load. (For example, see Patent Documents 2 and 3).
Depending on the optical waveguide, a pattern may also be formed on the clad layer, and in this case, a method of forming by exposure / development is employed (see, for example, Patent Document 4).

JP-A-63-083011 JP-A-6-258537 JP 2003-195079 A JP 2005-326602 A

By the way, in the formation process of the clad layer patterned by development / exposure, there is a problem that the aqueous solution such as a developing solution or a cleaning solution is poor in water even if air blow or the like is used, and workability is lowered.
In addition, a watermark (water removal trace) tends to remain on the surface of the formed patterned clad layer, and if such a watermark exists so as to cross the core pattern, the visibility of the core pattern is lowered. At the same time, there is a problem that it is difficult to distinguish the foreign object.

  The present invention has been made to solve the above problem, and improves the liquid (water) breakage on the surface of the clad layer on which the optical waveguide is patterned without reducing the productivity, so that it is difficult for the watermark to remain. An object of the present invention is to provide a method for manufacturing an optical waveguide and an optical waveguide with good core pattern visibility.

The inventors of the present invention are likely to cause water cuts or watermarks on the surface of the patterned clad layer due to the presence of monovalent salt generated on the clad layer in the process of forming a pattern by exposure and development. Focused on the thing.
That is, in order to enable pattern formation by exposure / development, an optical waveguide forming material to which an alkali development process can be applied is used when forming an optical waveguide pattern. The optical waveguide forming material contains a compound into which a functional group showing acidity such as a carboxyl group or a phenolic hydroxyl group is introduced in order to make it soluble in an alkaline developer.
Since the compound is contained, even in the pattern insolubilized by exposure, the functional group showing acidity is neutralized by the alkaline developer to form a salt. In particular, when an alkaline developer containing an alkali metal compound such as sodium carbonate, potassium carbonate, sodium hydroxide or potassium hydroxide or an organic base such as tetramethylammonium hydroxide is used as the developer, the monovalent salt is Generated.

If such a monovalent salt remains in the core pattern, it may cause problems such as an increase in light propagation loss and a decrease in reliability of the optical waveguide. On the other hand, in a clad layer that does not directly propagate an optical signal, it is considered that there is no particular problem even if a monovalent salt remains, and from the viewpoint of productivity, the monovalent in the patterned clad layer. Generally, it is considered that the necessity of providing a process for removing the salt is low.
However, the present inventors have noted that the monovalent salt tends to be chemically unstable and tends to be highly hydrophilic, and the 1 remaining in the patterned cladding layer. It was thought that the salt of the valent salt affects the ease of running out of water and the watermark.

  As a result of intensive studies, the inventors have conducted a step of impregnating a patterned cladding layer with metal ions having a valence of 2 or higher, or a step of washing the patterned cladding layer with an acidic solution. The present inventors have found that the salt can be easily and efficiently removed and can solve the above-mentioned problems, thereby completing the present invention.

That is, the present invention provides the following (1) to (19).
(1) A method of manufacturing an optical waveguide having a clad layer and a core pattern embedded in the clad layer, the method comprising the step of impregnating a patterned clad layer with bivalent or higher metal ions. Method.
(2) The method for producing an optical waveguide according to (1), wherein the divalent or higher-valent metal ions are magnesium ions and / or calcium ions.
(3) The clad layer developed and patterned is impregnated with divalent or higher metal ions using a step of exposing the clad layer, a step of developing with an alkaline developer, and a cleaning solution containing divalent or higher metal ions. The manufacturing method of the optical waveguide as described in said (1) or (2) which has a process.
(4) The step of exposing the clad layer and development with an alkaline developer containing divalent or higher metal ions to form a patterned clad layer, and at the same time, divalent or higher metal ions in the patterned clad layer The manufacturing method of the optical waveguide as described in said (1) or (2) which has the process of impregnating.
(5) The method for producing an optical waveguide according to (3) or (4), wherein the alkaline developer is an alkaline aqueous solution.
(6) The method according to any one of (1) to (5), further including a step of washing the clad layer with an acidic solution after the step of impregnating the patterned clad layer with metal ions having a valence of 2 or more. Manufacturing method of optical waveguide.
(7) A method of manufacturing an optical waveguide having a clad layer and a core pattern embedded in the clad layer, the step of exposing the clad layer, the step of developing with an alkaline developer, and the developed and patterned clad A method for producing an optical waveguide, comprising a step of washing a layer with an acidic solution.
(8) The method for producing an optical waveguide according to (6) or (7), wherein the acidic solution is one or more selected from hydrochloric acid, a sulfuric acid aqueous solution, and a nitric acid aqueous solution.
(9) The method for producing an optical waveguide according to any one of (6) to (8), wherein the acidic solution has a pH of more than 0 to 5;
(10) A step of washing the clad layer with pure water after the step of impregnating the patterned clad layer with metal ions having a valence of 2 or higher, or after the step of washing the patterned clad layer with an acidic solution. The manufacturing method of the optical waveguide in any one of said (1)-(9) which has these.
(11) The method for manufacturing an optical waveguide according to (10), further including a step of drying and curing the clad layer after the step of washing the clad layer with pure water.
(12) The method for manufacturing an optical waveguide according to (11), wherein the curing treatment is performed by photocuring and / or heat curing.
(13) The method for producing an optical waveguide according to the above (12), wherein the curing temperature at the time of thermosetting is 150 ° C. to 250 ° C.
(14) Any of the above (1) to (13), wherein the clad layer is formed by laminating a resin film for forming a clad layer having a resin layer made of a photosensitive resin composition for forming a clad layer. The manufacturing method of the optical waveguide as described in any one of.
(15) The method for producing an optical waveguide according to the above (14), wherein the photosensitive resin composition for forming a cladding layer contains a compound having a carboxyl group.
(16) The said photosensitive resin composition for clad layer formation contains (A) carboxyl group containing alkali-soluble polymer, (B) polymeric compound, and (C) The photoinitiator as described in said (15). Manufacturing method of optical waveguide.
(17) An optical waveguide obtained by sequentially laminating a lower clad layer, a core pattern, and an upper clad layer obtained by the manufacturing method according to any one of (1) to (16) above.
(18) The optical waveguide according to (17), wherein the lower cladding layer is formed on a substrate.
(19) The upper clad layer is patterned and contains metal ions having a valence of 2 or more, and the metal ions having a valence of 2 or more are moved upward from a boundary surface between the upper cladding layer and the core pattern. The optical waveguide according to (17) or (18), which is contained in the upper clad layer at a position of 5 μm or more.

  According to the method of manufacturing an optical waveguide of the present invention, the light (water) of the clad layer of the optical waveguide is good, the watermark is difficult to remain, and the core pattern has good visibility without reducing productivity. A waveguide can be obtained.

Hereinafter, the method for manufacturing an optical waveguide and the optical waveguide of the present invention will be described in detail.
The present invention relates to a method for manufacturing an optical waveguide having a cladding layer and a core pattern embedded in the cladding layer.
The configuration of the optical waveguide includes (a) an optical waveguide formed by sequentially laminating a lower clad layer and a core pattern, and (b) an optical waveguide obtained by sequentially laminating a lower clad layer, a core pattern, and an upper clad layer. For example, the lower cladding layer may be an optical waveguide formed on the substrate.

The optical waveguide manufacturing method of the present invention is classified into the following (1) and (2).
(1) A method for manufacturing an optical waveguide, which includes a step of impregnating a patterned clad layer of the optical waveguide with metal ions having a valence of 2 or more (hereinafter also referred to as “first manufacturing method”).
(2) A method for manufacturing an optical waveguide (hereinafter referred to as “second manufacturing method”), which includes a step of exposing a clad layer, a step of developing with an alkaline developer, and a step of washing the developed and patterned clad layer with an acidic solution. ”).

In the first manufacturing method, the monovalent salt generated on the surface of the patterned clad layer is divalent or higher by performing a step of impregnating the patterned clad layer with metal ions having a bivalent or higher valence. And the monovalent salt can be efficiently removed.
In the first production method, the following methods (1a) and (1b) are mentioned as methods for impregnating the clad layer with metal ions having a valence of 2 or more.
(1a) The step of exposing the clad layer, the step of developing with an alkaline developer, and the step of impregnating the developed and patterned clad layer with divalent or higher metal ions using a cleaning solution containing divalent or higher metal ions (1b) The step of exposing the clad layer, and developing with an alkaline developer containing a divalent or higher metal ion to form a patterned clad layer, and at the same time, the patterned clad layer is divalent or higher Through the process of impregnating metal ions of

In the optical waveguide obtained by the first manufacturing method, the patterned clad layer contains bivalent or higher metal ions.
The optical waveguide obtained by the first manufacturing method is an optical waveguide obtained by sequentially laminating a lower clad layer, a core pattern, and an upper clad layer, and the upper clad layer is patterned and contains metal ions having a valence of 2 or more. In this case, it is preferable that the metal ions having a valence of 2 or more are contained in the upper cladding layer at a position of 5 μm or more upward from the interface between the upper cladding layer and the core pattern.
By containing a metal ion having a valence of 2 or more at the above position in the upper cladding layer, the influence of the metal ion on the optical signal propagating through the core pattern is reduced, and an optical waveguide having excellent reliability can be obtained. it can.
The position where the metal ions having a valence of 2 or more contained in the upper clad layer are the concentration of the cleaning solution and the cleaning time in the method (1a), and the concentration and the developing time of the developer in the method (1b). Adjustment can be made by appropriately setting.

Further, in the second production method, the patterned clad layer is washed with an acidic solution to restore the functional group of the compound of the clad layer forming material to the original monovalent salt. Can be removed.
In the first manufacturing method, from the viewpoint of further improving the visibility of the core pattern, after the step of impregnating metal ions having a valence of 2 or more, the patterned clad layer is acidified as in the second manufacturing method. It is preferable to go through a step of washing with a solution.

The optical waveguide of the present invention may have a lower clad layer formed on a substrate.
The substrate used is not particularly limited, but is a silicon substrate, glass substrate, glass epoxy resin substrate, plastic substrate, metal substrate, substrate with resin layer, substrate with metal layer, plastic film, plastic film with resin layer, metal layer Attached plastic film, electric wiring board and the like.

  The method for forming the lower clad layer, the core layer, and the upper clad layer (hereinafter abbreviated as each layer) on the substrate is not particularly limited. For example, spin coating using a photosensitive resin composition for forming each layer, dipping Examples thereof include a coating method, a spray method, a bar coating method, a roll coating method, a curtain coating method, a gravure coating method, a screen coating method, and an inkjet coating method.

  When the photosensitive resin composition for forming each layer is a photosensitive resin varnish for forming each layer diluted with a suitable organic solvent, a drying step may be added after forming the resin layer as necessary. Examples of the drying method include heat drying and reduced pressure drying. Moreover, you may use these together as needed.

As another method of forming each layer, there is a method of forming each layer forming photosensitive resin film made of each layer forming photosensitive resin film by a laminating method.
Each layer-forming photosensitive resin film has a three-layer structure in which a resin layer made of each layer-forming photosensitive resin composition and a protective film are laminated on the resin film, as will be described in detail later. Are preferably used.
From the viewpoint that an optical waveguide manufacturing process with excellent productivity can be provided and the surface smoothness of the photosensitive resin film for forming each layer can be easily kept constant, lamination is performed using the photosensitive resin film for forming each layer as described above. The method of manufacturing by the method is preferred.

  Hereinafter, although the manufacturing method of the optical waveguide which forms the lower clad layer, the core part, and the upper clad layer using the photosensitive resin film for forming each layer will be described as an example, the present invention is not limited thereto. .

[First Step: Formation of Lower Cladding Layer]
First, as a first step, a photosensitive resin film for forming a lower clad layer is laminated on a substrate as described above. Although there is no restriction | limiting in particular as a lamination | stacking method in a 1st process, For example, the method of laminating | stacking by crimping, heating using a roll laminator or a flat plate laminator, etc. are mentioned.

  In the present invention, the flat plate laminator refers to a laminator in which a laminated material is sandwiched between a pair of flat plates and pressed by pressing the flat plate. For example, a vacuum pressurizing laminator can be suitably used. .

  The heating temperature here is preferably 20 to 130 ° C., and the pressure bonding pressure is preferably 0.1 to 1.0 MPa, but these conditions are not particularly limited. When a protective film exists in the photosensitive resin film for forming the lower cladding layer, the protective film is laminated after removing the protective film.

  In addition, before lamination by a vacuum pressure laminator, a photosensitive resin film for forming a lower clad layer may be temporarily pasted on a substrate using a roll laminator. Here, from the viewpoint of improving adhesion and followability, it is preferable to perform temporary bonding while pressing, and when pressing, a laminator having a heat roll may be used while heating.

The laminating temperature is preferably 20 to 130 ° C, more preferably 40 to 100 ° C. If it is 20 degreeC or more, the adhesiveness of the photosensitive resin film for lower clad layer formation and a board | substrate will improve, and if it is 130 degrees C or less, a resin layer does not flow too much at the time of roll lamination, and the required film thickness is can get.
The pressure during lamination is preferably 0.2 to 0.9 MPa, and the lamination speed is preferably 0.1 to 3 m / min, but these conditions are not particularly limited.

  When the lower clad layer is not patterned, the lower clad layer forming photosensitive resin film laminated on the substrate is photocured, the lower clad layer forming photosensitive resin film is removed, and the lower clad layer is removed. Form.

<Clad layer pattern exposure process>
Hereinafter, although the lower clad layer will be described, the method can be similarly applied to the upper clad layer.
When the lower clad layer is patterned by exposure and development, the lower clad layer forming resin composition is preferably composed of a photosensitive resin composition capable of forming a pattern with actinic rays. The irradiation amount of the actinic ray when forming the lower clad layer is preferably 0.1 to 5 J / cm ² , but these conditions are not particularly limited. The exposure method for patterning is not particularly limited, but for example, a method of irradiating an actinic ray in an image form through a negative mask pattern called artwork, direct activation without passing through a photomask using laser direct drawing The method etc. which irradiate a light beam on an image are mentioned. The lower clad layer may be exposed through the support film of the lower clad layer forming photosensitive resin film or after the support film is removed.
Further, after exposure, post-exposure heating may be performed as necessary from the viewpoint of improving the resolution and adhesion of the core pattern. The time from ultraviolet irradiation to post-exposure heating is preferably within 10 minutes. Within 10 minutes, active species generated by UV irradiation are not deactivated. The post-exposure heating temperature is preferably 40 to 160 ° C., and the time is preferably 30 seconds to 10 minutes.

<Clad layer development process>
When exposed through the support film of the photosensitive resin film for forming the lower clad layer, this is removed and developed using an alkaline developer.
The development method is not particularly limited, and examples thereof include a spray method, a dip method, a paddle method, a spin method, a brushing method, and a scraping method. Moreover, you may use these image development methods together as needed.
Although there is no restriction | limiting in particular as an alkaline developing solution, For example, the alkaline aqueous solution which consists of alkaline aqueous solution, alkaline aqueous solution, and 1 or more types of organic solvent etc. are mentioned, An alkaline aqueous solution is preferable.

The base of the alkaline aqueous solution is not particularly limited, and examples thereof include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; alkali metal carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate; Alkali metal bicarbonates such as lithium hydrogen carbonate, sodium hydrogen carbonate and potassium hydrogen carbonate; alkali metal phosphates such as potassium phosphate and sodium phosphate; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; Sodium salts such as sodium borate and sodium metasilicate; ammonium salts such as ammonium carbonate and ammonium hydrogen carbonate; tetramethylammonium hydroxide, triethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3- Professional Njioru, organic bases such as 1,3-diamino-propanol-2-morpholine.

These bases of the alkaline aqueous solution can be used alone or in combination of two or more.
The pH of the alkaline aqueous solution used for development is preferably 9-14, more preferably 10-13. The temperature of the alkaline aqueous solution used for development is adjusted according to the developability of the photosensitive resin layer for forming the lower cladding layer. Moreover, you may mix surfactant, an antifoamer, etc. in alkaline aqueous solution.

Further, as the alkaline developer, an alkaline quasi-aqueous developer composed of an alkaline aqueous solution and one or more organic solvents can be used.
The pH of the alkaline quasi-aqueous developer is preferably as low as possible within a range where development can be sufficiently performed. Specifically, it is preferably 8 to 13, and more preferably 9 to 12.

The organic solvent is not particularly limited, and examples thereof include alcohols such as methanol, ethanol, isopropanol, butanol, ethylene glycol, propylene glycol and diethylene glycol; ketones such as acetone, methyl ethyl ketone and 4-hydroxy-4-methyl-2-pentanone. And polyhydric alcohol alkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.
These organic solvents can be used alone or in combination of two or more.
The concentration of the organic solvent is usually preferably 2 to 90% by mass, and the temperature of the alkaline quasi-aqueous developer is adjusted according to the developability of the photosensitive resin layer for forming the lower clad layer.
Further, a small amount of a surfactant, an antifoaming agent or the like may be mixed in the alkaline quasi-aqueous developer.

  In the first method for producing an optical waveguide of the present invention, as a method for impregnating a patterned clad layer with a metal ion having a valence of 2 or more, as in the method (1b), alkaline development containing a metal ion with a valence of 2 or more is used. A method of developing using a liquid is mentioned.

The divalent or higher-valent metal ion in the alkaline developer is not particularly limited. For example, magnesium ion, calcium ion, zinc ion, manganese (II) ion, cobalt (II) ion, iron (II) ion, copper (II) ions, iron (III) ions, aluminum ions and the like.
Among these, from the viewpoint of the stability of the generated salt, a divalent metal ion is preferable, and a magnesium ion and / or a calcium ion is more preferable.
These metal ions can be used alone or in combination of two or more.

  A method for preparing an alkaline developer containing a divalent or higher valent metal ion is not particularly limited, and examples thereof include magnesium sulfate, calcium sulfate, zinc sulfate, manganese sulfate, cobalt sulfate, iron sulfate, copper sulfate, and aluminum sulfate. Metal sulfate salts: Magnesium chloride, calcium chloride, zinc chloride, manganese chloride, cobalt chloride, iron chloride, copper chloride, aluminum chloride and other metal chloride salts; magnesium carbonate, calcium carbonate, zinc carbonate, manganese carbonate, cobalt carbonate, Metal carbonates such as iron carbonate, copper carbonate, aluminum carbonate; metal water such as magnesium hydroxide, calcium hydroxide, zinc hydroxide, manganese hydroxide, cobalt hydroxide, iron hydroxide, copper hydroxide, aluminum hydroxide Examples thereof include a method of mixing or dissolving a compound such as an oxide in an alkaline developer.

Moreover, you may use the water which originally contains the said metal ion as an alkaline developing solution.
Such water is not particularly limited, and examples thereof include tap water and well water.

The content of divalent or higher-valent metal ions contained in the alkaline developer is preferably 0.0001 to 5.0% by mass, more preferably 0.001 to 3.0% by mass, and still more preferably 0.003 to 0.003%. 2.0% by mass.
If it is 0.0001% by mass or more, the unstable monovalent salt remaining at least near the surface of the lower cladding layer can be effectively converted into a stable divalent or higher salt, and 5% by mass or less. If so, no excessive metal ions remain at least near the surface of the lower cladding layer.

  As described above, development is performed using an alkaline developer containing divalent or higher metal ions, so that the development step becomes a step of impregnating the clad layer with divalent or higher metal ions. By impregnating a patterned clad layer with a metal ion having a valence of 2 or more, the liquid breakage is improved and the watermark is less likely to remain.

<Clad layer cleaning process>
In the first method for manufacturing an optical waveguide of the present invention, as a method for impregnating a patterned clad layer with a metal ion having a valence of 2 or more, a cleaning liquid containing a metal ion with a valence of 2 or more is used as in the method (1a). There is a method of cleaning the clad layer patterned by use.
Note that the developer used for development may or may not contain divalent or higher metal ions.

The divalent or higher valent metal ions in the cleaning liquid are not particularly limited, and examples thereof include magnesium ions, calcium ions, zinc ions, manganese (II) ions, cobalt (II) ions, iron (II) ions, copper (II ) Ion, iron (III) ion, aluminum ion and the like.
Among these, from the viewpoint of the stability of the generated salt, a divalent metal ion is preferable, and magnesium and / or calcium is more preferable.
These metal ions can be used alone or in combination of two or more.

  A method for preparing a cleaning solution containing a divalent or higher metal ion is not particularly limited. For example, metals such as magnesium sulfate, calcium sulfate, zinc sulfate, manganese sulfate, cobalt sulfate, iron sulfate, copper sulfate, and aluminum sulfate are used. Sulfates; metal chloride salts such as magnesium chloride, calcium chloride, zinc chloride, manganese chloride, cobalt chloride, iron chloride, copper chloride, aluminum chloride; magnesium carbonate, calcium carbonate, zinc carbonate, manganese carbonate, cobalt carbonate, iron carbonate Metal carbonates such as copper carbonate and aluminum carbonate; metal hydroxides such as magnesium hydroxide, calcium hydroxide, zinc hydroxide, manganese hydroxide, cobalt hydroxide, iron hydroxide, copper hydroxide and aluminum hydroxide And a method of dissolving such a compound in water.

  Moreover, you may use the water which originally contains the said metal ion as a washing | cleaning liquid. Such water is not particularly limited, and examples thereof include tap water and well water.

The content of metal ions contained in the cleaning liquid is preferably 0.0001 to 5.0% by mass, more preferably 0.001 to 3.0% by mass, and still more preferably 0.003 to 2.0% by mass. is there.
If it is 0.0001% by mass or more, unstable monovalent salt remaining at least near the surface layer of the lower cladding layer can be converted into a stable divalent or higher salt, and if it is 5% by mass or less, It is possible to suppress excessive metal ions from remaining at least near the surface of the lower cladding layer.
Moreover, you may mix an organic solvent, surfactant, an antifoamer, etc. in a washing | cleaning liquid.

  The cleaning method is not particularly limited, and examples thereof include a spray method, a dipping method, a paddle method, a spin method, a brushing method, and a scraping method. Moreover, you may use these washing | cleaning methods together as needed.

  As described above, by washing the patterned clad layer with a washing liquid containing divalent or higher metal ions, the cleaning step becomes a step of impregnating the clad layer with divalent or higher metal ions. By impregnating a patterned clad layer with a metal ion having a valence of 2 or more, the liquid breakage is improved and the watermark is less likely to remain.

In the second method of manufacturing an optical waveguide of the present invention, the monovalent salt remaining on the surface of the cladding layer can be effectively removed by washing the patterned cladding layer with an acidic solution.
The step of washing with an acidic solution is not particularly limited as long as it is after development, and is carried out after washing with a washing solution containing divalent or higher metal ions even after development using an alkaline developer containing divalent or higher metal ions. Also good.

There is no restriction | limiting in particular as an acidic solution, For example, inorganic acids, such as a sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid; Carboxylic acids, such as formic acid, an acetic acid, malonic acid, a succinic acid; Lactic acid, a salicylic acid, malic acid, tartaric acid, a citric acid An aqueous solution of a hydroxy acid or the like. These can be used alone or in combination of two or more.
Among these, at least one selected from hydrochloric acid, aqueous sulfuric acid, and aqueous nitric acid is preferable from the viewpoint of effectively removing the monovalent salt remaining on the surface of the cladding layer and from the viewpoint of availability. From the viewpoints of high volatility, low volatility and low oxidizing power, a sulfuric acid aqueous solution is more preferable.

The pH of the acidic solution is preferably more than 0 and 5 or less, more preferably 0.1 to 4, and still more preferably 0.3 to 3.
If the pH exceeds 0, the acidity and corrosivity are not too strong, and if the pH is 5 or less, the unstable monovalent salt remaining in the lower cladding layer is converted to the original acidic functionality. Can be effectively converted to the base.
The temperature of the acidic solution is adjusted according to the pH.
Further, an organic solvent, a surfactant, an antifoaming agent, and the like may be further mixed into the acidic solution.

  The cleaning method is not particularly limited, and examples thereof include a spray method, a dipping method, a paddle method, a spin method, a brushing method, and a scraping method. Moreover, you may use these washing | cleaning methods together as needed.

  As described above, by washing the patterned clad layer with an acidic solution, salt generated at least near the surface layer of the patterned clad layer can be effectively removed and converted to the original acidic functional group. The cutting performance is improved and the watermark is less likely to occur.

<Post-processing after cleaning with cleaning solution>
As the treatment after washing with the washing liquid, it is preferable to go through a step of washing using water or a mixed solution composed of water and the above organic solvent from the viewpoint of preventing impregnation of excess metal ions in the cladding layer, It is more preferable to go through a step of washing with pure water.
An organic solvent can be used individually or in combination of 2 or more types.
The concentration of the organic solvent in the mixed solution is preferably 2 to 90% by mass.

Moreover, it is preferable to dry and harden the patterned clad layer after the step of washing with water or a mixed solution.
The drying temperature is preferably 60 to 250 ° C, more preferably 70 to 150 ° C.
The curing treatment is preferably performed by at least one of photocuring and heat curing.
The light irradiated when performing photocuring is preferably ultraviolet light. Further, the exposure amount of light is preferably 0.1 to 7 J / cm ² , more preferably 0.4 to 5 J / cm ² .
Moreover, as heating temperature at the time of thermosetting, Preferably it is 150-250 degreeC, More preferably, it is 160-200 degreeC, As heating time in the said heating temperature, Preferably it is 30 minutes-3 hours, More preferably Is 40 minutes to 2 hours.
By performing the heat treatment, the watermark is less likely to remain even after a process in which the subsequent cladding layer is immersed in an aqueous solution.

[Second Step: Formation of Core Pattern]
As a second step, a core pattern is formed on the lower cladding layer.
Although there is no limitation in particular as a formation method, the resin film for core pattern formation is laminated | stacked on a lower clad layer by the method similar to a 1st process. Here, the core pattern forming resin film is preferably made of a photosensitive resin composition that is designed to have a higher refractive index than the clad layer forming resin film and can form the core pattern with actinic rays.

  Next, the core pattern is exposed. The method for exposing the core pattern is not particularly limited. Like the pattern exposure of the lower cladding layer, a method of irradiating actinic rays in an image form through a negative mask pattern called artwork, a photomask using laser direct drawing For example, a method of directly irradiating an image with an actinic ray without passing therethrough may be mentioned.

The amount of active light irradiation when exposing the core pattern is preferably 0.01 to 10 J / cm ² , more preferably 0.05 to 5 J / cm ² , and still more preferably 0.1 to 3 J / cm ² . .
If it is 0.01 J / cm ² or more, the curing reaction will proceed sufficiently, and the core pattern will not be washed away by the development process described later, and if it is 10 J / cm ² or less, the core pattern will become thick due to excessive exposure. This is preferable because a fine core pattern can be formed.

The exposure of the core pattern may be performed through the support film of the core portion forming photosensitive resin film or after the support film is removed.
Further, after exposure, post-exposure heating may be performed as necessary from the viewpoint of improving the resolution and adhesion of the core pattern.
The time from ultraviolet irradiation to post-exposure heating is preferably within 10 minutes. Within 10 minutes, active species generated by UV irradiation are not deactivated.
The post-exposure heating temperature is preferably 40 to 160 ° C., and the time is preferably 30 seconds to 10 minutes.

Subsequently, when exposed through the support film of the photosensitive resin film for core formation, this is removed and it develops using a developing solution.
The development method is not particularly limited, and examples thereof include a spray method, a dip method, a paddle method, a spin method, a brushing method, and a scraping method. Moreover, you may use these image development methods together as needed.
Although there is no restriction | limiting in particular as a developing solution, For example, the alkaline aqueous solution which consists of alkaline aqueous solution, alkaline aqueous solution, and 1 or more types of organic solvent, the various solvent in which the uncured part of a core layer dissolves, etc. are mentioned. In the case of development with an alkaline solution, it can be performed by the same method as the development and washing of the lower clad layer described above.
As a treatment after washing, drying may be performed as necessary.
Further, if necessary, the core pattern may be further cured by heating at 60 to 250 ° C. or exposure at 0.1 to 1000 mJ / cm ² and using these in combination.

[Third Step: Formation of Upper Cladding Layer]
As a third step, a photosensitive resin film for forming an upper clad layer is laminated on the lower clad layer and / or the core pattern by the same method as in the first and second steps. Here, the photosensitive resin film for forming the upper cladding layer is designed to have a lower refractive index than the photosensitive resin film for forming the core pattern. Further, the thickness of the upper clad layer is preferably larger than the height of the core pattern.

In the present invention, when forming the patterned upper cladding layer, as described above, the step of impregnating the patterned upper cladding layer with metal ions having a valence of 2 or more, and the patterned upper cladding layer with an acidic solution. At least one of the steps of washing is performed.
By passing through this step, the visibility of the core pattern from the upper cladding layer side is improved.
In addition, by passing through this step, there is an effect of imparting alcohol resistance and water resistance, and in the subsequent step, the step of immersing in alcohols such as methanol, ethanol, isopropyl alcohol or water, or these solutions The reliability of the optical waveguide in the exposed environment (the effect of reducing the propagation loss of the optical signal propagating in the core pattern) can be improved.
Alcohol resistance of the optical waveguide obtained through at least one of the step of impregnating the patterned upper cladding layer with metal ions having a valence of 2 or more and the step of washing the patterned upper cladding layer with an acidic solution From the viewpoint of obtaining an optical waveguide with improved reliability of the obtained optical waveguide, a patterned upper cladding layer is formed in this step. It is preferable to pass through a step of impregnating with divalent or higher metal ions.

In the optical waveguide of the present invention, the increment of light propagation loss before and after being immersed in methanol for 5 minutes is preferably 0.6 dB or less, more preferably 0.2 dB or less.
In addition, the increment of the optical propagation loss before and after immersing the optical waveguide in methanol for 5 minutes means a value measured by the method described in the examples.

Next, when the upper clad layer is not patterned, the entire surface of the upper clad layer forming photosensitive resin layer (film) is photocured by the same method as in the first step to form the upper clad layer.
When patterning the upper cladding layer, as in the first step, exposure treatment, development treatment, washing treatment with a divalent or higher-valent metal ion or acid solution, washing treatment with water or a mixed solution, drying What is necessary is just to perform a process, a photocuring process, and a thermosetting process.
The irradiation amount of actinic rays when forming the upper cladding layer is preferably 0.1 to 30 J / cm ² , but these conditions are not particularly limited.
When the upper clad layer is made to be a salt having a valence of 2 or more, it should be replaced only from the upper surface of the core pattern to a position 5 μm or more above (a salt having a valence of 2 or more is not permeated within 5 μm on the core pattern). The thickness or material composition of the upper cladding layer may be adjusted as appropriate so as to satisfy the above.

[Photosensitive resin composition for forming clad layer]
Hereinafter, the photosensitive resin composition for forming a clad layer, which is a material for forming the resin layer of the resin film for forming a clad layer, used for forming the clad layer of the optical waveguide of the present invention will be described.
The photosensitive resin composition for forming a clad layer, which is a material for forming the lower clad layer and the upper clad layer, is a compound having a carboxyl group from the viewpoint of enabling development of a desired pattern using an alkaline developer after exposure. It is preferable that it is a resin composition containing.
Furthermore, the photosensitive resin composition for forming a clad layer comprises (A) a carboxyl group-containing alkali-soluble polymer, (B) a polymerizable compound, and (C) a photopolymerization start from the viewpoints of transparency, heat resistance, and storage stability. More preferably, the resin composition contains an agent.
In addition, you may use said photosensitive resin composition for clad layer formation as a forming material of the resin layer of the resin film for core pattern formation. However, the resin layer of the core pattern forming resin film is designed to have a higher refractive index than the resin layer of the cladding layer forming resin film.

<(A) component: carboxyl group-containing alkali-soluble polymer>
Although there is no restriction | limiting in particular as a carboxyl group containing alkali-soluble polymer of (A) component, For example, the polymer etc. which are represented by following (1)-(6) are mentioned.
(1) A carboxyl group-containing alkali-soluble polymer obtained by copolymerizing a compound having a carboxyl group and an ethylenically unsaturated group in the molecule with another compound having an ethylenically unsaturated group.

(2) Partially introducing an ethylenically unsaturated group into the side chain into a copolymer of a compound having a carboxyl group and an ethylenically unsaturated group in the molecule and another compound having an ethylenically unsaturated group A carboxyl group-containing alkali-soluble polymer obtained in this manner.

(3) A compound having a carboxyl group and an ethylenically unsaturated group in the molecule in a copolymer of a compound having an epoxy group and an ethylenically unsaturated group in the molecule and another compound having an ethylenically unsaturated group And a carboxyl group-containing alkali-soluble polymer obtained by reacting a polybasic acid anhydride with the generated hydroxyl group.

(4) A compound having an hydroxyl group and an ethylenically unsaturated group in the molecule is reacted with a copolymer of an acid anhydride having an ethylenically unsaturated group and another compound having an ethylenically unsaturated group. Obtained carboxyl group-containing alkali-soluble polymer.

(5) A carboxyl group-containing alkali-soluble polymer obtained by reacting a polybasic acid anhydride with a polyaddition product of a bifunctional epoxy resin and a dicarboxylic acid or a bifunctional phenol compound.

(6) A carboxyl group-containing alkali-soluble polymer obtained by reacting a polybasic acid anhydride with a hydroxyl group of a polyaddition product of a bifunctional oxetane compound and a dicarboxylic acid or a bifunctional phenol compound.

Among these, a carboxyl group-containing alkali-soluble polymer represented by the above (1) to (4) is preferable from the viewpoint of transparency and solubility in an alkaline developer.
These polymers are (meth) acrylic polymers having a (meth) acryloyl group. Here, the (meth) acryloyl group is an acryloyl group and / or methacryloyl group, and the (meth) acrylic polymer is a monomer of acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, and derivatives thereof. And a polymer obtained by polymerizing this.
The (meth) acrylic polymer may be a homopolymer of the above monomer or a copolymer obtained by polymerizing two or more of the above monomers. Further, the copolymer may contain the above monomer and, if necessary, a monomer other than the above having an ethylenically unsaturated group other than the (meth) acryloyl group as long as the effects of the present invention are not impaired. Good. Further, it may be a mixture of a plurality of (meth) acrylic polymers.

The weight average molecular weight of the carboxyl group-containing alkali-soluble polymer as the component (A) is preferably 1,000 to 3,000,000, more preferably 3,000 to 2,000,000, and still more preferably 5,000 to 1. , 000,000. If the molecular weight is 1,000 or more, the strength of the cured product is sufficient when the resin composition is used, and if it is 3,000,000 or less, the solubility in a developer composed of an alkaline aqueous solution and (B) polymerization The compatibility with the functional compound is good.
The weight average molecular weight in the present invention is a value measured by gel permeation chromatography (GPC) and converted to standard polystyrene.

In the step of forming a pattern by development, the carboxyl group-containing alkali-soluble polymer (A) can have an acid value so that it can be developed with the alkaline developer.
For example, when the alkaline aqueous solution is used, the acid value of the carboxyl group-containing alkali-soluble polymer of the component (A) is preferably 20 to 300 mgKOH / g, more preferably 30 to 250 mgKOH / g, still more preferably 40 to 200 mgKOH. / G.
When the acid value is 20 mgKOH / g or more, development is easy, and when the acid value is 300 mgKOH / g or less, the developer resistance is not lowered.
The developer resistance refers to a property that a portion that is not removed by development and becomes a pattern is not affected by the developer.

When an alkaline quasi-aqueous developer composed of an alkaline aqueous solution and one or more organic solvents is used, the acid value of the carboxyl group-containing alkali-soluble polymer as the component (A) is preferably 10 to 260 mgKOH / g, more preferably Is 20 to 250 mgKOH / g, more preferably 30 to 200 mgKOH / g.
If the acid value is 10 mgKOH / g or more, development is easy, and if the acid value is 260 mgKOH / g or less, the developer resistance is not lowered.

  (A) The compounding quantity of a component becomes like this. Preferably it is 10-85 mass% with respect to the total amount of (A) component and (B) component, More preferably, it is 20-80 mass%, More preferably, it is 25-75 mass%, More preferably, it is 30-60 mass%. If it is 10% by mass or more, the strength and flexibility of the cured product of the photosensitive resin composition for forming an optical waveguide are sufficient, and if it is 85% by mass or less, it is easily entangled by the component (B) during exposure. The developer resistance is not insufficient.

<(B) component: polymerizable compound>
There is no restriction | limiting in particular as a polymeric compound of (B) component, For example, the compound which has polymeric substituents, such as an ethylenically unsaturated group, the compound which has two or more epoxy groups in a molecule | numerator, etc. are mentioned suitably. .

Examples of the polymerizable compound of component (B) include (meth) acrylate, vinylidene halide, vinyl ether, vinyl ester, vinyl pyridine, vinyl amide, arylated vinyl and the like. Among these, (meth) acrylate and arylated vinyl are preferable from the viewpoint of transparency.
As the (meth) acrylate, any of monofunctional, bifunctional, or trifunctional or higher polyfunctional ones can be used.

There is no restriction | limiting in particular as monofunctional (meth) acrylate, For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) Acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, butoxyethyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate , Octyl heptyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate Tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3- Aliphatic (meth) acrylates such as chloro-2-hydroxypropyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate; cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, di Cycloaliphatic (meth) acrylates such as cyclopentenyl (meth) acrylate and isobornyl (meth) acrylate; phenyl (meth) acrylate, nonylphenyl (meth) acrylate, p- Milphenyl (meth) acrylate, o-biphenyl (meth) acrylate, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3- (o-phenylphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (1-naphthoxy) propyl (meth) acrylate, 2-hydroxy-3- (2-naphthoxy) propyl (meth) Aromatic (meth) acrylate such as acrylate; heterocyclic such as 2-tetrahydrofurfuryl (meth) acrylate, N- (meth) acryloyloxyethylhexahydrophthalimide, 2- (meth) acryloyloxyethyl-N-carbazole (Meth) acrylate These ethoxylated products; these propoxylated products; these ethoxylated propoxylated products; these caprolactone-modified products and the like.
Among these, from the viewpoint of transparency and heat resistance, the above alicyclic (meth) acrylates; the above heterocyclic (meth) acrylates; these ethoxylated products; these propoxylated products; these ethoxylated propoxylated products. These modified caprolactones are preferred.

There is no restriction | limiting in particular as bifunctional (meth) acrylate, For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene Glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 2-methyl-1,3-propanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate , Neopentyl glycol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 2-butyl-2-ethyl-1, 3-propanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, glycerin di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate Aliphatic (meth) acrylates such as: cyclohexanedimethanol (meth) acrylate, ethoxylated cyclohexanedimethanol (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, hydrogenated bisphenol A di (meth) acrylate, hydrogenated bisphenol F And alicyclic (meth) acrylates such as acrylates; aromatic (meta) such as bisphenol A di (meth) acrylate, bisphenol F di (meth) acrylate, bisphenol AF di (meth) acrylate, and fluorene type di (meth) acrylate ) Acrylate; heterocyclic (meth) acrylates such as di (meth) acrylate of isocyanuric acid; ethoxylated compounds thereof; propoxylated compounds thereof; ethoxylated propoxylated compounds thereof; modified caprolactones thereof; neopentyl glycol type Aliphatic epoxy (meth) acrylates such as epoxy (meth) acrylates; cyclohexanedimethanol type epoxy (meth) acrylate, hydrogenated bisphenol A type epoxy (meth) acrylate, hydrogenated bisphenol F type epoxy (meth) acrylate Alicyclic epoxy (meth) acrylates such as resorcinol type epoxy (meth) acrylate, bisphenol A type epoxy (meth) acrylate, bisphenol F type epoxy (meth) acrylate, bisphenol AF type epoxy (meth) acrylate, fluorene type epoxy Examples include aromatic epoxy (meth) acrylates such as (meth) acrylates.
Among these, from the viewpoint of transparency and heat resistance, the above alicyclic (meth) acrylates; the above aromatic (meth) acrylates; the above heterocyclic (meth) acrylates; these ethoxylated products; and these propoxylated products. These ethoxylated propoxy compounds; these caprolactone-modified products; the above alicyclic epoxy (meth) acrylates; and the above aromatic epoxy (meth) acrylates.

The trifunctional or higher polyfunctional (meth) acrylate is not particularly limited. For example, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra ( Aliphatic (meth) acrylates such as meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate; heterocyclic (meth) acrylates such as isocyanuric acid tri (meth) acrylate; these ethoxy These propoxylated products; These ethoxylated propoxylated products; These caprolactone modified products; Phenol novolac epoxy (meth) acrylate, Cresol novolac epoxy (meta Aromatic epoxy (meth) acrylates such as acrylate.
Among these, from the viewpoint of transparency and heat resistance, the above heterocyclic (meth) acrylates; these ethoxylated products; these propoxylated products; these ethoxylated propoxylated products; these caprolactone modified products; Group epoxy (meth) acrylates are preferred.

  The above-mentioned monofunctional (meth) acrylate, bifunctional (meth) acrylate, and trifunctional or higher polyfunctional (meth) acrylate can be used alone or in combination of two or more. In addition, (meth) acrylates having different numbers of functional groups can be used in combination. Furthermore, it can also be used in combination with other polymerizable compounds.

  Moreover, as a polymeric compound of (B) component other than the above-mentioned (meth) acrylate, the compound which has two or more epoxy groups in a molecule | numerator from a compatible viewpoint with (A) carboxyl group-containing alkali-soluble polymer. Is preferred.

Examples of the compound having two or more epoxy groups in the molecule include hydroquinone type epoxy resin, resorcinol type epoxy resin, catechol type epoxy resin, bisphenol A type epoxy resin, tetrabromobisphenol A type epoxy resin, and bisphenol F. Type epoxy resin, bisphenol AF type epoxy resin, bisphenol AD type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, etc .; bifunctional phenol glycidyl ether type epoxy resin; hydrogenated bisphenol A type epoxy resin, water Hydrogenated bifunctional phenol glycidyl ether type epoxy resin such as hydrogenated bisphenol F type epoxy resin, hydrogenated 2,2′-biphenol type epoxy resin, hydrogenated 4,4′-biphenol type epoxy resin; Multifunctional or more polyfunctional phenol glycidyl ether type epoxy such as enol novolac type epoxy resin, cresol novolak type epoxy resin, dicyclopentadiene-phenol type epoxy resin, dicyclopentadiene-cresol type epoxy resin, tetraphenylolethane type epoxy resin Resin: Polyethylene glycol type epoxy resin, polypropylene glycol type epoxy resin, neopentyl glycol type epoxy resin, bifunctional aliphatic alcohol glycidyl ether type epoxy resin such as 1,6-hexanediol type epoxy resin; cyclohexanediol type epoxy resin, cyclohexane Bifunctional alicyclic alcohol glycidyl ether type epoxy resin such as dimethanol type epoxy resin and tricyclodecane dimethanol type epoxy resin; Trifunctional or higher polyfunctional aliphatic alcohol glycidyl ether type epoxy resin such as trimethylolpropane type epoxy resin, sorbitol type epoxy resin, glycerin type epoxy resin; Bifunctional aromatic glycidyl ester such as diglycidyl phthalate; Tetrahydrophthalic acid Bifunctional alicyclic glycidyl esters such as diglycidyl ester and hexahydrophthalic acid diglycidyl ester; bifunctional aromatic glycidyl amines such as N, N-diglycidylaniline and N, N-diglycidyltrifluoromethylaniline; 3 such as N, N ′, N′-tetraglycidyl-4,4-diaminodiphenylmethane, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, N, N, o-triglycidyl-p-aminophenol Multifunctional aromatic grease more than functional Ziramine; bifunctional alicyclic epoxy resin such as alicyclic diepoxy acetal, alicyclic diepoxy adipate, alicyclic diepoxycarboxylate, vinylcyclohexene dioxide; 2,2-bis (hydroxymethyl) -1- Trifunctional or higher polyfunctional alicyclic epoxy resin such as 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of butanol; Trifunctional or higher polyfunctional heterocyclic epoxy resin such as triglycidyl isocyanurate; Examples include silicon-containing bifunctional or trifunctional or higher polyfunctional epoxy resins such as organopolysiloxane type epoxy resins.
Among these, from the viewpoint of transparency and heat resistance, the above bifunctional phenol glycidyl ether type epoxy resin; the above hydrogenated bifunctional phenol glycidyl ether type epoxy resin; the above trifunctional or more polyfunctional phenol glycidyl ether type epoxy resin; Bifunctional alicyclic alcohol glycidyl ether phenol glycidyl ether type epoxy resin; bifunctional aromatic glycidyl ester phenol glycidyl ether type epoxy resin; bifunctional alicyclic glycidyl ester phenol glycidyl ether type epoxy resin; bifunctional alicyclic type The polyfunctional alicyclic epoxy resin; the polyfunctional heterocyclic epoxy resin; the bifunctional or polyfunctional silicon-containing epoxy resin is preferable.
These compounds can be used alone or in combination of two or more, and can also be used in combination with other polymerizable compounds.

  (B) The compounding quantity of the polymeric compound of component becomes like this. Preferably it is 15-90 mass% with respect to the total amount of (A) component and (B) component, More preferably, it is 20-80 mass%, More preferably, it is 25-25. It is 75 mass%, More preferably, it is 30-60 mass%. If it is 15% by mass or more, it can be easily entangled and cured with the carboxyl group-containing alkali-soluble polymer of component (A), and the developer resistance is not insufficient. The film has sufficient film strength and flexibility.

<(C) component: photopolymerization initiator>
(C) There is no restriction | limiting in particular as long as it initiates superposition | polymerization by irradiation of actinic rays, such as an ultraviolet-ray, as a photoinitiator of a component, For example, it has an ethylenically unsaturated group as a polymeric compound of (B) component In the case of using a compound, a photo radical polymerization initiator and the like can be mentioned.

There is no restriction | limiting in particular as radical photopolymerization initiator, For example, benzoin ketals, such as 2, 2- dimethoxy- 1, 2- diphenyl ethane- 1-one; 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl -1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4 [4 Α-hydroxy ketones such as-(2-hydroxy-2-methylpropionyl) benzyl] phenyl} -2-methylpropan-1-one; methyl phenylglyoxylate, ethyl phenylglyoxylate, 2- (2-hydroxyoxyphenylacetate) Ethoxy) ethyl, oxyphenylacetic acid 2- (2-oxo-2-phenylacetoxyethoxy) Glyoxyesters such as ethyl; 2-benzyl-2-dimethylamino-1- (4-morpholin-4-ylphenyl) -butan-1-one, 2-dimethylamino-2- (4-methylbenzyl)- 1- (4-Morpholin-4-ylphenyl) -butan-1-one, 1,2-methyl-1- [4- (methylthio) phenyl]-(4-morpholin) -2-ylpropane-1 Α-amino ketones such as —one; 1,2-octanedione, 1- [4- (phenylthio), 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) ) -9H-carbazol-3-yl], 1- (O-acetyloxime) and other oxime esters; bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6- Phosphine oxides such as methoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2 -(O-chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4 2,4,5-triarylimidazole dimers such as 2,5,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer; benzophenone, N, N′-tetra Methyl-4,4′-diaminobenzophenone, N, N′-tetraethyl-4,4′-diaminoben Benzophenone compounds such as phenone and 4-methoxy-4′-dimethylaminobenzophenone; 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, 2,3 -Quinone compounds such as dimethyl anthraquinone; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether and benzoin phenyl ether; benzoins such as benzoin, methyl benzoin and ethyl benzoin Compound; benzyl compounds such as benzyl dimethyl ketal; 9-phenyl acridine, 1,7-bis (9,9'-acridinyl heptane) or the like of acridine compounds: N- phenylglycine, coumarin and the like.
In the 2,4,5-triarylimidazole dimer, the substituents of the aryl groups at the two triarylimidazole sites may give the same and symmetric compounds, but give differently asymmetric compounds. May be.
These radical photopolymerization initiators can be used alone or in combination of two or more. Further, it may be used in combination with an appropriate sensitizer.

Moreover, when using an epoxy resin as a polymeric compound of (B) component, a photocationic polymerization initiator etc. are mentioned as a photoinitiator of (C) component.
Examples of photocationic polymerization initiators include aryl diazonium salts such as p-methoxybenzenediazonium hexafluorophosphate; diaryliodonium salts such as diphenyliodonium hexafluorophosphate and diphenyliodonium hexafluoroantimonate; triphenylsulfonium hexafluorophosphate, triphenylsulfonium Triarylsulfonium salts such as hexafluoroantimonate, diphenyl-4-thiophenoxyphenylsulfonium hexafluorophosphate, diphenyl-4-thiophenoxyphenylsulfonium hexafluoroantimonate, diphenyl-4-thiophenoxyphenylsulfonium pentafluorohydroxyantimonate; Triphenylselenonium hexaf Triarylselenonium salts such as orophosphate, triphenylselenonium tetrafluoroborate and triphenylselenonium hexafluoroantimonate; dialkylphenacylsulfonium such as dimethylphenacylsulfonium hexafluoroantimonate and diethylphenacylsulfonium hexafluoroantimonate Salts; dialkyl-4-hydroxy salts such as 4-hydroxyphenyldimethylsulfonium hexafluoroantimonate and 4-hydroxyphenylbenzylmethylsulfonium hexafluoroantimonate; α-hydroxymethylbenzoin sulfonate, N-hydroxyimide sulfonate, α- Examples thereof include sulfonic acid esters such as sulfonoxy ketone and β-sulfonyloxy ketone.

  Among these, the above triarylsulfonium salts are preferable from the viewpoints of curability, transparency, and heat resistance. These thermal and photocationic polymerization initiators can be used alone or in combination of two or more. Further, it may be combined with an appropriate sensitizer.

  (C) The compounding quantity of the photoinitiator of a component becomes like this. Preferably it is 0.1-10 mass parts with respect to 100 mass parts of total amounts of (A) component and (B) component, More preferably, it is 0.3-7. Part by mass, more preferably 0.5 to 5 parts by mass. If it is 0.1 parts by mass or more, curing is sufficient, and if it is 10 parts by mass or less, sufficient light transmittance is obtained.

<Thermosetting component>
Moreover, it is preferable to mix | blend a thermosetting component with the photosensitive resin composition for clad layer formation from a viewpoint of accelerating | stimulating hardening by a thermosetting process.
Examples of the thermosetting component include compounds having one or more epoxy groups in the molecule, polyfunctional blocked isocyanates such as an isocyanurate type trimer of hexamethylene diisocyanate, and the like.
The blending amount of the thermosetting component is preferably 0.1 to 30 parts by mass, more preferably 1 to 25 parts by mass, and still more preferably 3 to 100 parts by mass of the total amount of the component (A) and the component (B). 20 parts by mass.

<Other additives>
Moreover, the photosensitive resin composition for forming the clad layer includes, as necessary, an antioxidant, an anti-yellowing agent, an ultraviolet absorber, a visible light absorber, a colorant, a plasticizer, a stabilizer, a filler, and the like. You may mix | blend what is called an additive.
The compounding amount in the case of adding these additives is preferably 0.01 to 7 parts by mass, more preferably 0.02 to 3 parts by mass with respect to 100 parts by mass of the total amount of component (A) and component (B). Part.

In the present invention, the photosensitive resin composition for forming a cladding layer may be diluted with an organic solvent and used as a photosensitive resin varnish for forming a cladding layer.
The organic solvent used here is not particularly limited as long as it can dissolve the resin composition. For example, aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, p-cymene; tetrahydrofuran, 1,4- Cyclic ethers such as dioxane; alcohols such as methanol, ethanol, isopropanol, butanol, ethylene glycol, propylene glycol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone; methyl acetate , Esters such as ethyl acetate, butyl acetate, methyl lactate, ethyl lactate and γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate; ethylene glycol monomethyl ether, ethylene glycol monoester Ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol Polyhydric alcohol alkyl ethers such as dimethyl ether and diethylene glycol diethyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol Polyhydric alcohol alkyl ether acetates such as coal monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate; N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, etc. And amides.
These organic solvents can be used alone or in combination of two or more.
Moreover, the solid content concentration in the resin varnish is preferably 20 to 80% by mass.

[Clad layer forming resin film]
Hereinafter, the resin film for forming a clad layer used in the present invention will be described.
In addition, although the resin film for clad layer formation is demonstrated hereafter, it is the same also about the resin film for core pattern layer formation for forming a core pattern.
The photosensitive resin film for clad layer formation used by this invention has a resin layer which consists of the said photosensitive resin composition for clad layer formation.
As a manufacturing method of the resin film for forming a clad layer, the photosensitive resin varnish for forming a clad layer containing the components (A) to (C) described above is applied on a support film and dried to remove the solvent. Can be manufactured more easily. Moreover, you may manufacture by apply | coating the photosensitive resin composition for clad layer formation directly on a support film.

  Although there is no restriction | limiting in particular as a support film, For example, Polyester, such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; Polyolefin, such as polyethylene and a polypropylene; Polycarbonate, polyamide, polyimide, polyamideimide, polyetherimide, polyether sulfide, Examples include polyethersulfone, polyetherketone, polyphenylene ether, polyphenylene sulfide, polyarylate, polysulfone, and liquid crystal polymer.

  Among these, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene, polycarbonate, polyamide, polyimide, polyamideimide, polyphenylene ether, polyphenylene sulfide, polyarylate, and polysulfone are preferable from the viewpoints of flexibility and toughness.

Furthermore, a highly transparent support film is more preferable from the viewpoint of improving the transmittance of exposure actinic rays and reducing the side wall roughness of the core pattern.
Examples of such highly transparent support films include Cosmo Shine A1517 and Cosmo Shine A4100 manufactured by Toyobo Co., Ltd.
Further, from the viewpoint of improving the peelability from the resin layer, a support film that has been subjected to a release treatment with a silicone compound, a fluorine-containing compound, or the like on the surface of the above support film may be used as necessary.

  The thickness of the support film can be appropriately set depending on the intended flexibility, but is preferably 3 to 250 μm, more preferably 5 to 200 μm, and still more preferably 7 to 150 μm. If it is 3 μm or more, the film strength is sufficient, and if it is 250 μm or less, sufficient flexibility is obtained.

  The thickness of the support film of the resin film (and the core pattern forming resin film) for forming the patterned clad layer is preferably 5 to 50 μm, more preferably 10 to 40 μm, still more preferably 15 to 30 μm. It is. If it is 5 μm or more, the strength as a support is sufficient, and if it is 50 μm or less, the gap between the photomask and the resin layer composed of the photosensitive resin composition for pattern formation does not increase during pattern formation, and the pattern formability Is good.

In addition, the resin film for clad layer formation is good also as a three-layer structure which laminates | stacks a protective film on a resin layer further, and consists of a support film, a resin layer, and a protective film.
The protective film is not particularly limited, but from the viewpoint of flexibility and toughness, for example, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefins such as polyethylene and polypropylene are preferable.
Furthermore, from the viewpoint of improving the peelability from the resin layer, a protective film that has been subjected to a release treatment with a silicone compound, a fluorine-containing compound, or the like on the surface of the protective film may be used as necessary.

  The thickness of the protective film can be appropriately set depending on the intended flexibility, but is preferably 10 to 250 μm, more preferably 15 to 200 μm, and still more preferably 20 to 150 μm. If it is 10 μm or more, the film strength is sufficient, and if it is 250 μm or less, sufficient flexibility is obtained.

  Although there is no restriction | limiting in particular in the thickness of the resin layer of the resin film for clad layer formation, It is the thickness after drying, Preferably it is 5-500 micrometers. If the thickness is 5 μm or more, the thickness is sufficient so that the strength of the resin film or the cured product of the resin film is sufficient, and if it is 500 μm or less, the drying can be performed sufficiently and the amount of residual solvent in the resin film does not increase. When the cured resin film is heated, it does not foam.

  Thus, the obtained photosensitive resin film for layer formation can be easily preserve | saved by winding up in roll shape, for example. Alternatively, a roll-shaped film can be cut into a suitable size and stored in a sheet shape.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.
In addition, the weight average molecular weight and acid value of the (meth) acrylic polymer which is the base polymer of the resin film for forming a clad layer obtained in Production Example 1 were measured by the following methods.
(1) Weight average molecular weight Using gel permeation chromatography (GPC) (manufactured by Tosoh Corporation, product names “SD-8022”, “DP-8020”, and “RI-8020”) in terms of standard polystyrene ,It was measured. In addition, the Hitachi Chemical Co., Ltd. product name "Gelpack GL-A150-S" and "Gelpack GL-A160-S" were used for the column.
(2) Acid value 0.1 mol / L potassium hydroxide aqueous solution was dripped at the (meth) acrylic polymer solution produced | generated in manufacture example 1, and it computed from the amount of potassium hydroxide aqueous solution required for neutralization. At this time, the point at which the phenolphthalein added as an indicator changed color from colorless to pink was defined as the neutralization point.

Production Example 1
(Preparation of (meth) acrylic polymer solution)
46 parts by mass of propylene glycol monomethyl ether acetate and 23 parts by mass of methyl lactate are weighed in a flask equipped with a stirrer, a cooling pipe, a gas introduction pipe, a dropping funnel, and a thermometer, and stirred while introducing nitrogen gas. It was. The liquid temperature was raised to 65 ° C., 47 parts by weight of methyl methacrylate, 33 parts by weight of butyl acrylate, 16 parts by weight of 2-hydroxyethyl methacrylate, 14 parts by weight of methacrylic acid, 2,2′-azobis (2,4-dimethylvaleronitrile ) A mixture of 3 parts by weight, 46 parts by weight of propylene glycol monomethyl ether acetate, and 23 parts by weight of methyl lactate was added dropwise over 3 hours, followed by stirring at 65 ° C. for 3 hours and further stirring at 95 ° C. for 1 hour. A (meth) acrylic polymer solution (solid content: 45% by mass), which is a group-containing alkali-soluble polymer, was obtained.
The obtained (meth) acrylic polymer had a weight average molecular weight (in terms of standard polystyrene) of 3.9 × 10 ⁴ and an acid value of 79 mgKOH / g.

Production Example 2
(Preparation of resin varnish for forming clad layer)
(A) As a carboxyl group-containing alkali-soluble polymer, the (meth) acrylic polymer solution (solid content 45% by mass) obtained in Production Example 1 described above 84 parts by mass (solid content 38 parts by mass), (B) the polymerizable compound , 33 parts by mass of urethane (meth) acrylate having a polyester skeleton (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “U-200AX”), and urethane (meth) acrylate having a polypropylene glycol skeleton (Shin-Nakamura Chemical Co., Ltd.) ), Trade name “UA-4200”) 15 parts by mass, (C) As a photopolymerization initiator, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propane- 1 part by weight of 1-one (trade name “Irgacure 2959” manufactured by BASF AG) and bis (2,4,6-trimethylbenzoyl) phenylphos 1 part by mass of zinc oxide (manufactured by BASF, trade name “Irgacure 819”), (D) polyfunctional block isocyanate solution in which isocyanurate type trimer of hexamethylene diisocyanate is protected with methyl ethyl ketone oxime as a thermosetting component (Sumika Bayer) 20 parts by mass (solid content 15 parts by mass) of a product name “Sumijour BL3175”, solid content 75% by mass, and 23 parts by mass of propylene glycol monomethyl ether acetate as a diluting organic solvent are manufactured by Urethane Co., Ltd. To obtain a mixed solution.
Then, the mixed solution was subjected to pressure filtration using a polyflon filter having a pore size of 2 μm (trade name “PF020” manufactured by Advantech Toyo Co., Ltd.) and then degassed under reduced pressure to prepare a resin varnish for forming a cladding layer. .

Production Example 3
(Preparation of a resin film for forming a cladding layer)
The resin varnish for forming a clad layer prepared in Production Example 2 is coated on a non-treated surface of a polyethylene terephthalate film (PET film) (trade name “Cosmo Shine A4100”, thickness 50 μm, manufactured by Toyobo Co., Ltd.). (Hirano Techseed Co., Ltd., product name “Multi-Coater TM-MC”) applied, dried at 100 ° C. for 20 minutes to form a resin layer, and a PET film whose surface was peeled off as a protective film The release-treated surface of the Teijin DuPont Films, trade name “Purex A31”, thickness 25 μm) and the resin layer were bonded together to obtain a resin film for forming a cladding layer.
In addition, the film thickness of the clad layer of the resin film for forming the clad layer can be arbitrarily adjusted by adjusting the gap of the coating machine. Moreover, the film thickness of the clad layer after coating on the PET film was the same as the film thickness after curing. About the film thickness of the resin film for upper clad layer formation used by the present Example and the comparative example, it is as the description in the following Example, The film thickness of the resin film for upper clad layer formation is a film | membrane after coating Thickness.

Production Example 4
(Preparation of resin film for core layer formation)
As a base polymer, 26 parts by mass of a phenoxy resin (manufactured by Toto Kasei Co., Ltd., trade name “phenototoy YP-70”), and 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] as a polymerizable compound 36 parts by mass of fluorene (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “A-BPEF”) and 36 parts by mass of bisphenol A type epoxy acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “EA-1020”) As a photopolymerization initiator, 1 part by mass of bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (manufactured by BASF, trade name “Irgacure 819”), and 1- [4- (2-hydroxyethoxy) Phenyl] -2-hydroxy-2-methyl-1-propan-1-one (BASF, trade name “Irgacure 2959”) 1 part by mass And as the organic solvent, and mixed with stirring 40 parts by mass of propylene glycol monomethyl ether acetate to obtain a mixed solution.
Then, the mixed solution was subjected to pressure filtration using a polyflon filter having a pore size of 2 μm (trade name “PF020” manufactured by Advantech Toyo Co., Ltd.) and then degassed under reduced pressure to prepare a resin varnish for forming a core layer. .

The resin layer varnish for core layer formation prepared as described above is applied to a non-treated surface of a PET film (trade name “Cosmo Shine A1517”, thickness 16 μm, manufactured by Toyobo Co., Ltd.) in the same manner as in Production Example 3 above. Applied and dried to form a resin layer, and as a protective film, a PET film (trade name “Purex A31”, 25 μm thickness, manufactured by Teijin DuPont Films Ltd.) with a release treatment on the surface And a resin layer were bonded together to obtain a core layer forming resin film.
In addition, the film thickness of the core layer of the resin film for core layer formation can be arbitrarily adjusted by adjusting the gap of a coating machine. About the film thickness of the resin film for core layer formation used by the present Example and the comparative example, it is as the description in the following Example, The film thickness of the resin film for core layer formation is the film thickness after coating, and To do.

Example 1
(1) Formation of lower clad layer On a 100 mm × 100 mm polyimide film (polyimide; Upilex RN (manufactured by Ube Nitto Kasei), thickness: 25 μm) as a substrate, the thickness of the clad layer obtained in Production Example 3 is 15 μm. After peeling off the protective film of the resin film for forming the clad layer, a vacuum pressure laminator (manufactured by Meiki Seisakusho Co., Ltd., product name “MVLP-500”) is used to evacuate to 500 Pa or less, and then the pressure is 0.4 MPa. The film was laminated by thermocompression bonding under conditions of a temperature of 110 ° C. and a pressurization time of 30 seconds.
Subsequently, using an ultraviolet exposure machine (manufactured by Oak Manufacturing Co., Ltd., product name “EXM-1172”), the center of the opening and the center of the substrate through a negative photomask having an opening (90 mm × 90 mm) Were irradiated with ultraviolet rays (wavelength 365 nm) at 350 mJ / cm ² from the support film side of the clad layer forming resin film.
Thereafter, the support film of the resin film for forming a clad layer was peeled off, and developed using a 1% by mass potassium carbonate aqueous solution as a developer. Further, a 1% by mass calcium chloride aqueous solution was used as a cleaning solution, and the cleaning was performed for 30 seconds, and the lower cladding layer was impregnated with calcium ions. Further, using pure water, washing was performed for 30 seconds to perform washing treatment.
Next, a drying process is performed at 100 ° C., and from the formation surface side of the lower cladding layer, photocuring is performed by irradiating 3.0 J / cm ² using the ultraviolet exposure machine, and then heating at 170 ° C. for 1 hour, The clad layer was thermally cured to form a lower clad layer.

(2) Formation of Core Pattern Next, after peeling off the protective film of the core layer-forming resin film having a core layer thickness of 45 μm obtained in Production Example 4, from the formation surface side of the lower cladding layer formed as described above , Roll laminator (manufactured by Hitachi Chemical Technoplant Co., Ltd., product name “HLM-1500”) was laminated under the conditions of pressure 0.4 MPa, temperature 50 ° C., laminating speed 0.2 m / min. Next, using the above-described vacuum pressurization type laminator (product name “MVLP-500” manufactured by Meiki Seisakusho Co., Ltd.), after vacuuming to 500 Pa or less, pressure 0.4 MPa, temperature 70 ° C., pressurization time 30 Thermocompression bonding was performed under the conditions of seconds.

Subsequently, a negative photomask having openings (45 μm × 80 mm) provided at eight positions at a pitch of 250 μm from the support film side through the negative photomask so that the openings are on the lower cladding layer, Using the above ultraviolet exposure machine, ultraviolet rays (wavelength 365 nm) were irradiated at 0.8 J / cm ² , and heating was performed after exposure at 80 ° C. for 5 minutes. Thereafter, the PET film as the support film was peeled off, and etching was performed using a mixed solution of propylene glycol monomethyl ether acetate / N, N-dimethylacetamide = 8/2 (mass ratio) as a developer. Then, it wash | cleaned using isopropanol as a washing | cleaning liquid, and heat-dried at 100 degreeC for 10 minute (s), and formed the core pattern.

(3) Formation of upper clad layer After peeling off the protective film of the clad layer forming resin film having a thickness of 75 μm obtained in Production Example 3, the formation surface of the core pattern and the lower clad layer formed as described above From the side, using a vacuum pressurizing laminator (product name “MVLP-500” manufactured by Meiki Seisakusho Co., Ltd.), after vacuuming to 500 Pa or less, pressure 0.4 MPa, temperature 110 ° C., pressurization time 30 seconds The film was heat-pressed and laminated under the conditions.
Subsequently, using the ultraviolet exposure machine, the center of the opening and the center of the substrate are aligned through a negative photomask having an opening (90 mm × 90 mm), and the support film side of the resin film for forming the clad layer Then, ultraviolet rays (wavelength 365 nm) were irradiated at 350 mJ / cm ² .
Thereafter, the support film of the resin film for forming a clad layer was peeled off, and developed using a 1% by mass potassium carbonate aqueous solution as a developer. Further, a 1% by mass calcium chloride aqueous solution was used as a cleaning solution for 30 seconds, and the upper cladding layer was impregnated with calcium ions. Further, using pure water, washing was performed for 30 seconds to perform washing treatment.
Next, a drying treatment is performed at 100 ° C., and from the formation surface side of the upper clad layer, it is photocured by irradiation with 3.0 J / cm ² using the above-described ultraviolet exposure machine, and then heated at 170 ° C. for 1 hour, The clad layer was thermally cured to form an upper clad layer, and an optical waveguide was produced.

Examples 2-11, Comparative Examples 1-3
After the development of the lower clad layer and the upper clad layer, an optical waveguide was produced in the same manner as in Example 1 except that the washing liquids shown in Table 1 were used and washed in the order shown in Table 1.

The optical waveguides obtained in the above examples and comparative examples were evaluated based on the following methods. The results are shown in Table 1.
(1) Visibility of core pattern The core pattern of the obtained optical waveguide was visually observed and evaluated in 5 to 1 stages. Evaluation 5 has the highest visibility, and evaluation 1 has the lowest visibility.
(2) Increase in light propagation loss before and after immersing the optical waveguide in methanol The optical propagation loss of the obtained optical waveguide (waveguide length 10 cm) is a VCSEL (EXFO) with a light source having a wavelength of 850 nm as a light source. Product name “LS-300-01-VCL”), light receiving sensor (manufactured by Advantest Corporation, product name “Q82214”), incident fiber (GI-50 / 125 multimode fiber, NA = 0.20) , And the output fiber (SI-114 / 125, NA = 0.22). Thereafter, the optical waveguide was immersed in methanol for 5 minutes, and the optical propagation loss of the optical waveguide was measured in the same manner as described above. Table 1 shows the increment of light propagation loss of the optical waveguide after being immersed in methanol.

In the cleaning treatments in the lower clad layer and the upper clad layer in Examples 1 to 11, the water scavenging property after washing with each cleaning solution is good, and no watermark remains on the surfaces of the lower clad layer and the upper clad layer. It was.
In addition, even after drying the lower cladding layer and the upper cladding layer, after photocuring, and after thermal curing, no watermark remains on the surfaces of the lower cladding layer and the upper cladding layer, and the core pattern visibility is good. It was.
In addition, when the optical waveguides obtained in Examples 1 to 11 were immersed in methanol for 5 minutes, the increase in light propagation loss was suppressed to 0.6 dB or less, and the reliability of these optical waveguides was good. It was. Furthermore, since Examples 1, 3, 5, and 6 have undergone a process of impregnating a patterned clad layer with metal ions having a valence of 2 or more, the obtained optical waveguide has alcohol resistance and water resistance. As a result, the reliability of the optical waveguide was further improved.

Moreover, when the optical waveguide produced in Example 1 was cut | disconnected perpendicularly and the penetration depth of calcium was measured using the EDX analysis method (energy dispersive X-ray spectroscopy) from the cross-sectional direction, calcium was as follows. It was present in the upper cladding layer at a position of 10 μm above the boundary surface between the upper cladding layer and the core pattern, and the light propagation loss of the core pattern was also good.
Furthermore, when the optical waveguide produced in Examples 5 and 6 was cut perpendicularly and the penetration depth of calcium was measured from the cross-sectional direction using EDX analysis (energy dispersive X-ray spectroscopy), calcium was measured. Is present in the upper cladding layer at a position 5 μm below the position of 5 μm from the surface layer of the upper cladding layer and above the boundary surface between the upper cladding layer and the core pattern, and the light propagation loss of the core pattern is particularly It was good.

On the other hand, in Comparative Example 1, the water drainage of the lower clad layer was poor and a watermark remained. Even after drying after the formation of the upper clad layer, after photocuring, and after heat curing, the watermark remained, and the visibility of the core pattern was somewhat poor.
In Comparative Example 2, the water of the upper clad layer was poor and the watermark remained. Even after drying after the formation of the upper clad layer, after photocuring, and after thermosetting, the watermark remained and the visibility of the core pattern was poor.
In Comparative Example 3, both the lower clad layer and the upper clad layer had poor water drainage, and watermarks remained in both. Even after drying after the formation of the upper clad layer, after photocuring, and after thermosetting, the watermark remained and the visibility of the core pattern was particularly bad.
In addition, when the optical waveguides obtained in Comparative Examples 1 to 3 were immersed in methanol for 5 minutes, the increments of light propagation loss were 0.7 dB or more, respectively, resulting in inferior reliability as compared with the Examples. It was.

  By using the optical waveguide manufacturing method of the present invention, it is possible to obtain an optical waveguide manufacturing method with good liquid (water) cut-off, which makes it difficult for watermarks to remain, and an optical waveguide with good core pattern visibility. It can be applied to various fields such as various optical devices and optical interconnections.

Claims (19)

  A method of manufacturing an optical waveguide having a cladding layer and a core pattern embedded in the cladding layer, the method comprising impregnating a patterned cladding layer with bivalent or higher metal ions.   The method for producing an optical waveguide according to claim 1, wherein the divalent or higher-valent metal ions are magnesium ions and / or calcium ions.   The step of exposing the clad layer, the step of developing with an alkaline developer, and the step of impregnating the clad layer developed and patterned with a metal ion having a valence of 2 or more using a cleaning solution containing a metal ion having a valence of 2 or more. The manufacturing method of the optical waveguide of Claim 1 or 2.   The step of exposing the clad layer and developing with an alkaline developer containing divalent or higher metal ions to form a patterned clad layer, and simultaneously impregnating the patterned clad layer with divalent or higher metal ions The manufacturing method of the optical waveguide of Claim 1 or 2 which has a process.   The method for producing an optical waveguide according to claim 3, wherein the alkaline developer is an alkaline aqueous solution.   The method of manufacturing an optical waveguide according to claim 1, further comprising a step of washing the clad layer with an acidic solution after the step of impregnating the patterned clad layer with a metal ion having a valence of 2 or more.   A method of manufacturing an optical waveguide having a clad layer and a core pattern embedded in the clad layer, the step of exposing the clad layer, the step of developing with an alkaline developer, and the developing and patterning of the clad layer acidic A method for producing an optical waveguide, comprising a step of washing with a solution.   The method for producing an optical waveguide according to claim 6 or 7, wherein the acidic solution is at least one selected from hydrochloric acid, a sulfuric acid aqueous solution, and a nitric acid aqueous solution.   The method for manufacturing an optical waveguide according to claim 6, wherein the acidic solution has a pH of more than 0 to 5.   After the step of impregnating the patterned clad layer with metal ions having a valence of 2 or more, or after the step of washing the patterned clad layer with an acidic solution, the step of washing the clad layer with pure water, The manufacturing method of the optical waveguide in any one of Claims 1-9.   The method for manufacturing an optical waveguide according to claim 10, further comprising a step of drying and curing the clad layer after the step of washing the clad layer with pure water.   The method for manufacturing an optical waveguide according to claim 11, wherein the curing treatment is performed by photocuring and / or heat curing.   The manufacturing method of the optical waveguide of Claim 12 whose curing temperature at the time of thermosetting is 150 to 250 degreeC.   The optical waveguide according to any one of claims 1 to 13, wherein the cladding layer is formed by laminating a resin film for forming a cladding layer having a resin layer made of a photosensitive resin composition for forming a cladding layer. Production method.   The method for producing an optical waveguide according to claim 14, wherein the photosensitive resin composition for forming a cladding layer contains a compound having a carboxyl group.   The optical waveguide production according to claim 15, wherein the photosensitive resin composition for forming a cladding layer comprises (A) a carboxyl group-containing alkali-soluble polymer, (B) a polymerizable compound, and (C) a photopolymerization initiator. Method.   An optical waveguide obtained by sequentially laminating a lower clad layer, a core pattern, and an upper clad layer obtained by the manufacturing method according to claim 1.   The optical waveguide according to claim 17, wherein the lower cladding layer is formed on a substrate.   The upper clad layer is patterned and contains metal ions having a valence of 2 or more, and the metal ions having a valence of 2 or more are added upward from the boundary surface between the upper cladding layer and the core pattern by 5 μm or more. The optical waveguide according to claim 17, wherein the optical waveguide is contained in the upper cladding layer at a position.