JP4474857B2 - Manufacturing method of optical waveguide - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionManufacturing method of optical waveguideAbout.
[0002]
[Prior art]
As materials used for forming an optical waveguide for an optical circuit, inorganic materials such as quartz materials, various glass materials, light-transmitting oxide ferroelectrics, and various polymer materials are used. Among these materials, polymer materials are easier to form thin films using spin coating, dipping, etc. than inorganic materials, and are suitable for producing flexible and large-area optical waveguides. Yes.
In addition, the thin film formation method using such a polymer material does not include a heat treatment step at a high temperature when forming a film, as compared with a thin film formation method using an inorganic material such as quartz. There is an advantage that an optical waveguide can be manufactured even on a substrate that is difficult to heat-treat at a high temperature such as a plastic substrate.
Furthermore, it is possible to produce a flexible optical waveguide utilizing the flexibility and toughness of the polymer material. For this reason, optical waveguide components such as optical integrated circuits used in the field of optical communications and optical wiring boards used in the field of optical information processing can be manufactured in large quantities and at low cost using optical polymer materials. Expected.
[0003]
Conventionally, such optical polymer materials are inferior in terms of environmental resistance and weather resistance such as heat resistance and moisture resistance, and thus have been considered to have problems in maintaining the stability of optical properties. In recent years, improvements have been made. In addition, when a photosensitive polymer material is used as the optical polymer material, production such as formation and processing is very easy, and mass productivity is excellent.
However, conventionally used photosensitive polymer materials are polymer materials that are solid at room temperature. When a thick film is formed using such a polymer material, scattering in the ultraviolet region and visible region increases, resulting in light. The transparency deteriorates and the resolution when the polymer material is cured deteriorates even when a pattern such as an optical waveguide is formed using a photolithographic method. It was not possible to reproduce the above, and the transmission loss of the manufactured optical waveguide was also adversely affected.
[0004]
Furthermore, the photosensitive polymer materials conventionally used as described above are insufficient in consideration of characteristics required as an optical material such as a reduction in transmission loss in a wavelength region used for information transmission. It has the disadvantage of high waveguide loss. Therefore, an optical component such as an optical waveguide manufactured using such a photosensitive polymer material is insufficient from the viewpoint of practicality and durability.
[0005]
As a means for solving the above problems, a method of forming a pattern such as an optical waveguide using a liquid photocurable resin instead of a solid polymer material at room temperature has been considered. However, since this photocurable resin has fluidity, the coating film thickness changes after the photocurable resin is applied, thereby forming a pattern such as an optical waveguide with good reproducibility and controllability. I couldn't.
In addition, when pattern formation is performed using a conventional photosensitive material, an etching process or the like is necessary, and a large amount of harmful alkaline waste liquid is generated. There were difficulties such as complexity and lengthening.
[0006]
On the other hand, the wavelength range used for optical communication that is currently used as a large amount of information transmission means over long distances is generally the attenuation of quartz material, which is the main optical waveguide partial material used for such optical communication. In order to suppress this, infrared rays having a wavelength range of 1.3 μm to 1.5 μm are used. In addition, in order to meet the needs of large-scale information transmission by using light as an information transmission medium in the future, not only long distances as in the past, but also local areas (short distances) such as in homes and offices. Information transmission and processing in Japan is expected to expand rapidly.
[0007]
Optical materials used in such a large amount of information transmission and processing in a local area are not mainly used in the form of fibers only as in long-distance communication. In addition to fibers, connectors, optical waveguides, etc. Such various optical circuits are required to be processed and formed into a complicated form, to be easily connected, and to other various high-order functions. However, although the quartz material has no problem in terms of transmission loss, it is a brittle material, so its processing / formability is poor and it is difficult to handle and form a complicated pattern. Therefore, it is technically difficult to use a quartz material as an optical material for a local area.
[0008]
For this reason, resin materials have been highlighted as optical materials for information transmission in the local area in terms of processing / formability and ease of handling. This resin material is inferior in terms of transmission loss and transparency in the infrared region used in optical communication as compared with quartz material. However, regarding the transmission loss, since the transmission distance is short, a transmission loss like a quartz material is not required, and there is a possibility that a resin material can be used sufficiently.
[0009]
In addition, regarding the transparency in the infrared region, the conventional resin material contains many hydrogen atoms in its structure, so the transparency in the infrared region is insufficient for optical communication that will be required in the future. It was. However, it has been studied that light having a wavelength of 1.3 to 1.5 μm used for long-distance communication is converted into light having a shorter wavelength of about 850 nm and then distributed into the local area. Such an infrared ray having a short wavelength of about 850 nm is considered to be able to sufficiently cope with a resin material at a practical level.
[0010]
For example, by substituting hydrogen atoms in the resin material with other atoms, it has been found that there is a possibility that it can cope with optical communication in the infrared region although it has not been put into practical use (see Non-Patent Document 1).
In addition, as an optical component using an infrared transmitting resin material, for example, deuterium atoms or fluorine atoms are used as the hydrogen atoms of the organic polymer that forms the core portion having an initial transmission loss of 0.4 dB or less at a wavelength of 780 nm. Substituted optical transmission bodies (see Patent Document 1) and flat plastic optical waveguides (see Patent Document 2) using deuterated or halogenated polyacrylate, polysiloxane, or polystyrene have been proposed. .
[0011]
On the other hand, various optical components using a resin material are produced by spinning formation, for example, when producing an optical fiber. In the case of producing an optical waveguide, for example, a method of producing a core part by injection molding and a clad part by casting (see, for example, Patent Document 3), photolithography and dry etching are combined. (For example, refer to Patent Document 4).
[0012]
However, in the spinning formation, only fiber-like materials can be produced, and optical components having complicated shapes such as connectors and optical waveguides other than fibers cannot be produced. In addition, in injection molding and casting molding, various shapes can be manufactured, but it is difficult to manufacture an optical component having a fine and precise pattern.
On the other hand, the method combining dry etching and wet etching with photolithography can produce an optical component having a fine and precise pattern, but (1) the manufacturing process is complicated and the productivity is inferior. (2) ▼ Waste (resist, alkaline waste liquid, etc.) in a series of manufacturing processes is harmful and abundantly generated, so the burden on the environment is large / waste disposal cost is high. There are problems such as high manufacturing costs.
[0013]
On the other hand, the inventors of the present invention provided an image forming method and a color filter manufacturing method excellent in resolution by using an electrodeposition material containing a coloring material in advance and performing electrodeposition or photoelectrodeposition by applying a low voltage ( For example, see Patent Documents 5 to 10). These image forming methods and color filter manufacturing methods are characterized by forming colored films with high resolution by a simple method, but are mainly applied in the field of display devices such as liquid crystal display devices. .
[0014]
The electrodeposition method as described above is easy to form a fine pattern and has high productivity and less harmful waste liquid compared with a method in which dry or wet etching is combined with photolithography. However, at present, no attempt has been made to produce optical parts such as optical waveguides by electrodeposition.
Furthermore, since the electrodepositable polymer material used in the conventional electrodeposition method contains a lot of hydrogen atoms, it is expected to be necessary for short-range communication in the wavelength range used in optical communication, particularly in the local area. The light transmittance in the wavelength range of 700 nm to 1.35 μm is insufficient.
[0015]
[Patent Document 1]
Japanese Patent No. 2854669
[Patent Document 2]
Japanese Patent No. 2599497
[Patent Document 3]
Japanese Patent No. 2854669
[Patent Document 4]
Japanese Patent No. 2599497
[Patent Document 5]
Japanese Patent Laid-Open No. 10-119414
[Patent Document 6]
JP 11-189899 A
[Patent Document 7]
Japanese Patent Laid-Open No. 11-15418
[Patent Document 8]
JP-A-11-174790
[Patent Document 9]
JP-A-11-133224
[Patent Document 10]
JP-A-11-335894
[Non-Patent Document 1]
Maruno, IEICE Journal, Vol. 84, no. 9, pp 656-662, 2001
[0016]
[Problems to be solved by the invention]
  An object of the present invention is to solve the above problems. That is, the object of the present invention is to provide an optical waveguide having a small transmission loss and high accuracy by using an electrodeposition method or a photo-deposition method, which can easily form a fine pattern and has little harmful waste liquid.The roadSimple and can be manufactured with high productivityManufacturing method of optical waveguideIs to provide.
[0017]
[Means for Solving the Problems]
  The problem isManufacturing method of optical waveguideIt is solved by providing.
<1> A method of manufacturing an optical waveguide that transmits information using light in a wavelength range of at least a wavelength of 700 nm to 1350 nm,
The electrodeposition material includes at least an electrodeposition polymer material, 10% to 90% of hydrogen atoms constituting the electrodeposition polymer material are substituted with deuterium atoms, and the electrodeposition material is formed from the electrodeposition material. The first cladding layer, the core layer, and the second cladding are not dried by electrodeposition using an electrodeposition solution having a transmission loss of 1 dB / cm or less for light in the wavelength range of 700 nm to 1350 nm. Laminate layersCharacteristicOptical waveguideManufacturing method.
[0018]
  <2> The electrodepositable polymer material is at leastOne selected from alkenes, dienes, styrene, and derivatives thereofWith hydrophobic monomers, One selected from acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, crotonic acid, cinnamic acid, phthalic acid, and derivatives thereof<1> characterized by containing a copolymer obtained by polymerizing a hydrophilic monomer.Manufacturing method of optical waveguide.
[0019]
  <3>
  The electrodepositable polymer material is at leastOne selected from alkenes, dienes, styrene, and derivatives thereofWith hydrophobic monomers, Acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, crotonic acid, cinnamic acid, phthalic acid, and derivatives thereofWith hydrophilic monomers,<1> characterized by containing a copolymer obtained by polymerizing methacrylic acid esters, acrylic acid esters, maleic anhydride esters, and one kind of plastic monomer selected from these derivatives. Described inManufacturing method of optical waveguide.
[0020]
  <4> The electrodepositable polymer material contains a copolymer polymerized using at least one kind of monomer in which at least a part of hydrogen atoms constituting the monomer is substituted with deuterium atoms. As described in <1>Manufacturing method of optical waveguide.
[0021]
  <5> saidThe first clad layer, the core layer, and the second clad layer are formed on the release layer, and then the first clad layer, the core layer, and the second clad layer are transferred to the substrate.<The manufacturing method of the optical waveguide as described in 1>.
[0022]
  <6>The light is laser light having a wavelength of 850 nm.<The manufacturing method of the optical waveguide as described in 1>.
[0023]
  <7>20% to 60% of hydrogen atoms constituting the electrodepositable polymer material are substituted with deuterium atoms<The manufacturing method of the optical waveguide as described in 1>.
[0024]
  <8>The electrodeposition liquid contains fine particles for adjusting the refractive index.<The manufacturing method of the optical waveguide as described in 1>.
[0025]
  <9>The electrodepositable polymer material is a copolymer obtained by polymerizing at least a styrene monomer and an acrylic acid monomer, and at least a part of hydrogen atoms of the styrene monomer and / or the acrylic acid monomer before polymerization is deuterium. It is substituted with atoms, and the light is a laser beam having a wavelength of 850 nm<The manufacturing method of the optical waveguide as described in 1>.
[0026]
  <10>From the aqueous electrodeposition liquid containing the electrodepositable polymer material as an electrodeposition material, the electrodepositable polymer material is deposited to form the first clad layer, the core layer, and the second clad layer in a wet state. An electrodeposition film deposition / formation step and a drying step of drying the heat-treated first clad layer, core layer, and second clad layer in the moist state.<1>, a method of manufacturing an optical waveguide according to
The temperature of the heat treatment is within a range of ± 15 ° C. of the glass transition point (Tg) of the electrodepositable polymer material..
[0027]
  <11>From the aqueous electrodeposition liquid containing the electrodepositable polymer material as an electrodeposition material, the electrodepositable polymer material is deposited to form the first clad layer, the core layer, and the second clad layer in a wet state. An electrodeposition film deposition / formation step and a drying step of drying the heat-treated first clad layer, core layer, and second clad layer in the moist state.<1>, a method of manufacturing an optical waveguide according to
The method of manufacturing an optical waveguide, wherein the temperature of the heat treatment is in a range of 60 to 200 ° C.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the electrodeposition liquid of the present invention used for the formation of optical components such as optical waveguides, the electrodeposition method, the optical components such as optical waveguides, and the production method thereof will be roughly divided into the following.
[0040]
(Electrodeposition liquid)
First, the portion related to the optical characteristics of the electrodeposition film formed using the electrodeposition liquid of the present invention will be mainly described, and then the electrodeposition liquid and the optical characteristics of the electrodeposition film formed using the electrodeposition liquid will be described. The part related to other than will be mainly described.
[0041]
  That is, the present invention is an electrodeposition liquid capable of depositing an electrodeposition film made of an electrodeposition material containing an electrodeposition polymer material on a substrate, and comprising hydrogen atoms constituting the electrodeposition polymer material 10% to 90% are substituted with deuterium atoms, and the electrodeposition film has a transmission loss of 1 dB / cm or less with respect to light in a wavelength range of 700 nm to 1350 nm.
  However, in the present invention,A method of manufacturing an optical waveguide in which the first cladding layer, the core layer, and the second cladding layer are stacked without being dried by electrodeposition formation using an electrodeposition solution is employed..
[0042]
The electrodeposition liquid of the present invention can easily form a fine pattern, and by using an electrodeposition method or a photoelectrodeposition method with little harmful waste liquid, it is easy to make optical parts such as optical waveguides with a small transmission loss and a high accuracy. In addition, it can be manufactured with high productivity.
[0043]
When 10% to 90% of the hydrogen atoms constituting the electrodepositable polymer material are replaced with deuterium atoms, the light absorption rate in the infrared region due to the hydrogen atoms decreases, and thus The transmission loss of the electrodeposition film made of the electrodeposition material including the electrodeposition polymer material with respect to light in the wavelength range of 700 nm to 1350 nm can be suppressed to 1 dB / cm or less.
[0044]
The above transmission loss does not necessarily mean that the light is 1 dB / cm or less in the entire wavelength range of 700 nm to 1350 nm when the light is limited to a narrow wavelength band such as laser light. In the present invention, when the light used is laser light, at least in the wavelength range, the transmission loss is preferably in the wavelength band within the upper and lower ranges of 5 nm, more preferably in the upper and lower ranges of 10 nm with respect to a certain central wavelength λ nm May be 1 dB / cm or less.
[0045]
In the wavelength range of 700 nm to 1350 nm, the center wavelength λ is preferably a wavelength of 1300 nm or 1350 nm currently used. Further, in the near future, a wavelength range of 800 nm to 900 nm which is considered to be suitable for use in an optical material made of an organic material can be preferably used.
[0046]
In order to achieve such optical properties, it is necessary that 10% to 90% of the hydrogen atoms constituting the electrodepositable polymer material be replaced with deuterium atoms (hereinafter referred to as electrodeposition properties). The substitution of hydrogen atoms constituting molecules such as polymer materials with deuterium atoms may be abbreviated as “deuterium substitution”, and the substitution rate may be abbreviated as “deuterium atom substitution rate”). The deuterium atom substitution rate is represented by the molar ratio (%) of substituted deuterium atoms to all the hydrogen atoms constituting each polymer constituting the electrodepositable polymer material that is not deuterium substituted. The
[0047]
When the hydrogen atom constituting the electrodepositable polymer material has a deuterium atom substitution rate of less than 10%, the optical characteristics as described above cannot be achieved.
On the other hand, when the deuterium atom substitution rate is larger than 90%, problems occur in various characteristics other than the processing / formability of the electrodeposited film and the optical characteristics of the electrodeposited film. In addition, it may be difficult to produce an electrodepositable polymer material having such a deuterium atom substitution rate.
[0048]
The deuterium atom substitution rate is more preferably 20% to 60%, more preferably 30% to 60% from the viewpoints of the optical characteristics of the electrodeposited film as described above, various characteristics other than the optical characteristics, and the processing / formability of the electrodeposited film. 40% is more preferable.
[0049]
In order to easily deposit and form an electrodeposition film having optical characteristics as described above by electrodeposition, the electrodeposition polymer material has reduced solubility or dispersibility in an aqueous liquid due to pH change. A material is preferred. In order to satisfy such a condition, it is preferable that the electrodepositable polymer material contains a copolymer obtained by polymerizing at least a hydrophobic monomer and a hydrophilic monomer. Note that more detailed and desirable conditions for the electrodepositable polymer material will be described later.
[0050]
Furthermore, in order to suppress film quality deterioration after electrodeposition film formation such as film formation (adhesiveness on the substrate) of the formed electrodeposition film and generation of cracks due to changes in temperature and humidity, etc. The electrodepositable polymer material preferably contains a copolymer obtained by polymerizing at least a hydrophobic monomer, a hydrophilic monomer, and a plastic monomer.
Specific examples of the hydrophobic monomer, hydrophilic monomer, and plastic monomer as described above and other preferable characteristics will be described later.
[0051]
The electrodepositable polymer material used in the present invention is not particularly limited as long as it is deuterium substituted as described above, but the electrodepositable polymer material is at least one of hydrogen atoms constituting the monomer. It is preferable to contain a copolymer polymerized using at least one type of monomer in which part is deuterium substituted.
[0052]
That is, in a series of processes for synthesizing an electrodepositable polymer material comprising synthesis or preparation of a monomer as a starting material and polymerization using this monomer, an electrodeposition property is obtained using a monomer deuterated in advance. A polymeric material can be made.
[0053]
In addition, when synthesizing the electrodepositable polymer material by the method as described above, the ratio of the deuterium-substituted monomer in the monomer used and the deuterium atom substitution ratio of the deuterium-substituted monomer , Is not particularly limited.
However, the deuterium atom substitution rate of an electrodepositable polymer material comprising a copolymer polymerized using at least one monomer in which at least a part of hydrogen atoms constituting the monomer is substituted with deuterium However, it is necessary that both be selected so as to be within a range of 10% to 90%, and it is preferable that both be selected so as to be within a range of 25% to 60%.
When the deuterium substitution rate exceeds 60%, it becomes difficult to synthesize an electrodepositable polymer material, which requires a new synthesis step from the starting material, greatly increases the number of synthesis steps, and increases the production time. In some cases, the productivity is lowered and the manufacturing cost is increased. On the other hand, when the deuterium substitution rate is lower than 10%, the light transmission loss improving effect is lowered.
[0054]
In addition to the synthesis process described above, the electrodepositable polymer material used in the present invention is obtained through a synthesis process of deuterating a copolymer polymerized using only a monomer that is not deuterated. Of course it is possible. Whether the former synthesis process or the latter synthesis process is used is selected as necessary in consideration of various factors such as controllability of deuterium atom substitution rate, ease of polymerization, synthesis cost, etc. be able to.
[0055]
The former synthesis process is preferably used from the viewpoint of controllability of the deuterium substitution rate of the electrodepositable polymer material to be finally synthesized and ease of grasping the deuterium substitution rate.
This is because, in the former synthesis process, a deuterium-substituted monomer having a known deuterium ratio in the monomer (hereinafter sometimes abbreviated as “deuterium-substituted monomer”) is used. Therefore, the deuterium substitution rate of the electrodepositable polymer material can be easily calculated from the deuterium substitution rate of the deuterium substitution monomer and the ratio of the deuterium substitution monomer in the total monomers used in the synthesis, The deuterium substitution rate can be easily controlled by adjusting both values.
[0056]
An electrodepositable polymer material substituted with deuterium (hereinafter sometimes abbreviated as “substituted electrodeposition material”) is an electrodepositable polymer material that is not deuterated at all (hereinafter referred to as “unsubstituted electrodeposition material”). When the molecular structures of the two are substantially the same, other characteristics other than the transmission loss tend to be almost the same or close to each other.
On the other hand, in the design of conventional optical components such as optical waveguides, when selecting materials for the core layer and the cladding layer, it is necessary to determine the combination of materials in consideration of optical characteristics and various characteristics other than optical characteristics. was there. For example, in order to prevent the occurrence of cracks due to thermal shock or temperature change, it is necessary that the difference in the thermal expansion coefficients of the materials used for the core layer and the clad layer is small. That is, in the design of conventional optical components, it may be difficult to achieve both required optical characteristics and various characteristics other than the optical characteristics.
[0057]
However, when an optical component such as an optical waveguide is manufactured using a substituted electrodeposition material and a unsubstituted electrodeposition material having substantially the same molecular structure, with the former as a core layer and the latter as a cladding layer, for example, Since there is almost no difference in thermal expansion coefficient, it is not necessary to consider the occurrence of cracks.
As described above, when designing an optical component by combining a substituted electrodeposition material and an unsubstituted electrodeposition material, there are fewer mismatches and trade-offs between various characteristics other than transmission loss between optical materials used. Therefore, it is easier to design and optimize optical components than before.
[0058]
In addition, when a substituted electrodeposition material having the same or similar molecular structure is used in combination with an unsubstituted electrodeposition material, the durability of the electrodeposition film is reduced because the characteristics other than the transmission loss of both are close. This can be further improved, and the durability of optical components such as an optical waveguide manufactured using the same can be improved. In addition, since the refractive index of the electrodeposition film formed using the replacement electrodeposition material can be further improved, it can be used for other purposes and for various purposes as an optical member used when producing optical components. It becomes. Furthermore, by using a substitution electrodeposition material, a fine pattern of an optical component such as an optical waveguide can be formed with higher accuracy, and an optical component having excellent optical characteristics and a high degree of integration can be provided. That is, since the fine pattern can be formed with higher accuracy, the optical component can be further downsized, and the transmission loss due to the accuracy of the formed fine pattern can be further reduced.
[0059]
In addition, in order to form a fine pattern accurately or to form another layer on the surface of the electrodeposited film, the surface energy of the electrodeposited film is not preferable whether it is too large or too small. It is preferably in the range of approximately 27 to 53 dyn / cm. This is because, when the surface energy of the electrodeposition film is less than 27 dyn / cm, the patterning accuracy decreases, the adhesiveness with the film laminated on the surface of the electrodeposition film, This is because there is a case where a problem such as non-uniformity is likely to occur, and the patterning accuracy may be lowered even when it is larger than 53 dyn / cm.
However, in the electrodeposition film produced using the electrodeposition liquid of the present invention, the surface energy does not become too small or too large and can easily be within the range of 27 to 53 dyn / cm. Since it is possible, the above problems can be avoided.
[0060]
Next, the portions related to the electrodeposition liquid and other than the optical characteristics of the electrodeposition film formed using the same will be mainly described.
As described above, in order to facilitate the formation of an electrodeposited film by an electrodeposition method, the electrodepositable polymer material is a material whose solubility or dispersibility in an aqueous liquid decreases due to a change in pH. Preferably there is.
[0061]
In the present invention, as described above, the electrodepositable polymer material may contain a monomer having different properties, that is, a copolymer obtained by polymerizing at least a hydrophilic monomer and a hydrophobic monomer. It is important that the copolymer contains at least a copolymer obtained by polymerizing at least a hydrophilic monomer, a hydrophobic monomer, and a plastic monomer in addition to the former two monomers, and more desirably a plastic monomer. Is more desirable.
[0062]
When the electrodepositable polymer material contains such a copolymer, firstly, due to the action of the hydrophilic monomer unit, easy solubility in an aqueous medium can be secured, and second, the hydrophobic monomer unit. Due to the action, it is possible to quickly form an electrodeposition film with excellent water resistance due to its strong cohesive force. Third, the film formability (adhesiveness) on the electrodeposition material is improved by the action of the plastic monomer unit. In addition, by applying a low potential voltage, it is possible to form a film having a uniform film thickness and color density and having a smooth surface, and it is possible to avoid deterioration of film quality such as cracks after film formation (drying).
[0063]
In the case where the electrodepositable polymer material contains a copolymer obtained by polymerizing at least a hydrophilic monomer and a hydrophobic monomer, in the copolymer, the hydrophilic monomer to be copolymerized or the hydrophobic monomer The composition ratio (ratio of the number of hydrophilic monomers or hydrophobic monomers to the total number of monomers used for copolymerization (%)) is particularly high in precipitation efficiency due to pH change, and easily adheres, even at low potential. The following ranges are preferable in that a film can be formed and the liquid property of the electrodeposition solution can be stabilized.
[0064]
The composition ratio of the hydrophilic monomer to be copolymerized is 10 to 10 in that sufficient solubility or dispersibility is ensured with respect to the aqueous liquid (including the aqueous liquid subjected to pH adjustment).
-70% is preferable and 15-45% is more preferable.
If the composition ratio of the hydrophilic monomer is less than 10%, the solubility in water may be too low and may not be soluble in water, and if it exceeds 70%, it may be water-soluble to water-insoluble due to a change in pH, or On the other hand, it may be reversible and re-dissolved easily.
[0065]
The composition ratio of the hydrophobic monomer to be copolymerized is preferably 25 to 70%, more preferably 30 to 60%.
If the composition ratio of the hydrophobic monomer is less than 25%, the water resistance and film strength of the electrodeposition film may be insufficient. If the composition ratio exceeds 70%, the copolymer has an affinity for an aqueous solvent. The appropriate amount may not be dissolved due to the decrease, precipitation may occur, or the viscosity of the electrodeposition solution may become too high to form a uniform film.
On the other hand, it is preferable that the composition ratio of the hydrophobic monomer is within the above range because the affinity with the aqueous solvent is high, the liquidity of the electrodeposition liquid is stabilized, and the electrodeposition efficiency is high.
[0066]
From the above, from the viewpoint of steep change in state due to pH change and high hydrophilicity, styrene and its derivatives and (meth) acrylic acid and its derivatives are included in the copolymer component as monomers constituting the copolymer. A copolymer is particularly preferred.
[0067]
In the case where the electrodepositable polymer material contains a copolymer obtained by polymerizing at least a hydrophilic monomer, a hydrophobic monomer, and a plastic monomer, in the copolymer, a hydrophilic monomer to be copolymerized, a hydrophobic property The composition ratio of monomers and plastic monomers (ratio of the number of hydrophilic monomers, hydrophobic monomers, or plastic monomers to the total number of monomers used for copolymerization (%)) is particularly high in precipitation efficiency due to pH change. It is easy to adhere, can be formed even at a low potential, and exhibits a film-forming (hysteresis) characteristic that can form a uniform film, the liquid property of the electrodeposition liquid is stable, and it can be made a good film quality that hardly causes cracks, The ranges shown below are preferred.
[0068]
The composition ratio of the hydrophilic monomer to be copolymerized is preferably 10 to 30% from the viewpoint of ensuring sufficient solubility or dispersibility with respect to the aqueous liquid (including the aqueous liquid whose pH has been adjusted). 20% is more preferable.
If the composition ratio of the hydrophilic monomer is less than 10%, the solubility in water may be too low and may not be soluble in water. If it exceeds 30%, the water content may be insoluble due to a change in pH, or On the other hand, it may be reversible and re-dissolved easily.
[0069]
The composition ratio of the hydrophobic monomer to be copolymerized is preferably 15 to 45%, more preferably 25 to 39%.
When the composition ratio of the hydrophobic monomer is less than 15%, the water resistance and film strength of the electrodeposition film may be insufficient, and when it exceeds 45%, the copolymer has an affinity for an aqueous solvent. The appropriate amount may not be dissolved due to the decrease, precipitation may occur, or the viscosity of the electrodeposition solution may become too high to form a uniform film.
On the other hand, it is preferable that the composition ratio of the hydrophobic monomer is within the above range because the affinity with the aqueous solvent is high, the liquidity of the electrodeposition liquid is stabilized, and the electrodeposition efficiency is high.
[0070]
Furthermore, since the composition ratio of the plastic monomer affects the occurrence of cracks (cracks, etc.) in the formed electrodeposition film, it improves adhesion and adhesion to the electrodeposited material, improves film formability, and is dry. 30 to 70% is preferable and 40 to 58% is more preferable in terms of improving (softening) the later film quality.
If the composition ratio of the plastic monomer is less than 30%, the film formability deteriorates and a uniform film cannot be formed at a low potential, or cracks (film cracks) occur after film formation (drying). The film quality may deteriorate, and if it exceeds 70%, the mechanical strength of the film may be insufficient, or the formation of the edge portion may be lost.
[0071]
As described above, the glass transition point (Tg) of the copolymer is 5 to 150 ° C. in terms of imparting flexibility to the electrodeposition film and avoiding cracks (cracking) after film formation (drying). Preferably, 35-70 degreeC is more preferable.
The Tg value can be adjusted by changing the melting point and copolymerization ratio of the plastic monomer. For example, the copolymerization ratio of the plastic monomer may be changed according to the molecular weight.
[0072]
When the Tg value is less than 5 ° C., the mechanical strength and heat resistance of the film may be insufficient, or the formation of an edge may be poor. The film quality may not be maintained.
[0073]
The weight average molecular weight of the copolymer is preferably from 6000 to 30000, and more preferably from 13000 to 22000, from the viewpoint that the film properties (film thickness, surface smoothness, etc.) and the adhesive strength of the film are improved.
When the weight average molecular weight is less than 6000, the deposition amount of the electrodeposition material is small and the film is likely to be redissolved and the film may become non-uniform. When it exceeds 30000, cracks (cracks) occur in the electrodeposition film. Etc.) or the electrodeposited film may be pulverized and an electrodeposited film having high film quality fastness may not be obtained.
[0074]
The copolymer has a flow starting point of 180 ° C. or lower and a decomposition point of 150 ° C.
It is preferable that the temperature is higher than or equal to 220 ° C., preferably higher than or equal to 220 ° C., since the film properties of the electrodeposition film formed on the substrate are improved and deterioration due to subsequent electrodeposition is less likely to occur.
Further, the copolymer preferably has heat resistance. Specifically, the weight loss rate after heat treatment at 200 ° C. for 30 minutes is preferably within 10%, and at 250 ° C. for 30 minutes. More preferably, the weight loss rate after the heat treatment is within 5%.
[0075]
The balance between hydrophobicity and hydrophilicity required for a copolymer can be expressed, for example, by the number of hydrophobic monomers to be copolymerized and the number of hydrophilic monomers, but when the copolymer is an anionic polymer. Can also be represented by an acid value.
The acid value of the copolymer is preferably from 60 to 160, more preferably from 90 to 145, in view of good electrodeposition characteristics. If the acid value is less than 60, the affinity for an aqueous solvent may be lowered and precipitation may occur, or the viscosity of the electrodeposition solution may be too high, and a uniform electrodeposition film may not be formed, and exceeds 160. In such a case, the water resistance of the formed electrodeposition film may decrease, and the electrodeposition efficiency may decrease.
[0076]
The copolymer according to the present invention may be an anionic molecule having an anion dissociable group (for example, a carboxyl group) or a cation dissociable group (for example, an amino group, an imino group, etc.). It may be a cationic molecule. Which one is selected can be based on the solubility change characteristic corresponding to the change in pH of the electrodepositable polymer material.
[0077]
Among the copolymers, those copolymerized using a hydrophilic monomer containing a carboxyl group are preferable.
For example, in the case of an electrodepositable polymer material having a carboxyl group, the carboxyl group becomes dissociated and dissolves in an aqueous liquid when the pH is alkaline, and the dissociated state disappears and the solubility is reduced and precipitates in an acidic region. . In addition, the presence of the hydrophobic monomer unit, combined with the fact that the ion-dissociated group loses ionicity due to the change in pH as described above, provides the electrodepositable polymer material with a function of instantly depositing a film. Has been granted.
[0078]
The copolymer according to the present invention may be any of a block copolymer, a random copolymer, a graft copolymer, and a mixture thereof, more preferably a random copolymer or a block copolymer. Is preferred.
[0079]
The hydrophilic monomer constituting the copolymer has a property of being ionically dissociated in an aqueous liquid (including an aqueous liquid whose pH has been adjusted) and exhibiting sufficient solubility or dispersibility. The monomer preferably has a hydrophilic group capable of ion dissociation at least and exhibits hydrophilicity as a whole monomer.
[0080]
In addition, a specific characteristic of the hydrophilic monomer in terms of the molecular structure is that it always has an ion-dissociable hydrophilic group in the molecule. Examples of such a hydrophilic group include a carboxyl group, a hydroxyl group, and a sulfone group. Examples include acid groups
[0081]
Specific examples of the hydrophilic monomer include acrylic acid having 2 to 15 carbon atoms, more preferably 3 to 8 carbon atoms, derivatives thereof, methacrylic acid and derivatives thereof, maleic anhydride and derivatives thereof, fumaric acid and derivatives thereof. Preferred examples include crotonic acid and derivatives thereof, cinnamic acid and derivatives thereof, phthalic acid and derivatives thereof, and the like. In the copolymer, it suffices that at least one of the hydrophilic monomers is copolymerized, and two or more of them may be copolymerized.
[0082]
More specifically, as a hydrophilic monomer having an anionic dissociation group, for example, a monomer having a carboxyl group such as methacrylic acid, acrylic acid, maleic anhydride, propiolic acid, fumaric acid, itaconic acid, and derivatives thereof Is mentioned.
Among these, methacrylic acid, acrylic acid, and derivatives thereof are preferable because ionic molecules using these as monomers are steep in change in state due to change in pH and high in hydrophilicity to aqueous liquids.
[0083]
These hydrophilic monomers may be those obtained by substituting at least a part of hydrogen atoms in the molecule with deuterium atoms, as described above.
[0084]
The hydrophobic monomer that constitutes the copolymer has the property that its solubility changes due to changes in the hydrogen ion concentration (pH) and exhibits water insolubility. The monomer is preferably hydrophobic.
[0085]
In addition, a specific characteristic of the hydrophobic monomer in terms of the molecular structure is that it always has a hydrophobic group in the molecule. Such a hydrophobic group is not particularly limited as long as it exhibits hydrophobicity. Although not necessarily mentioned, for example, groups composed of nonpolar or small polar atomic groups such as chain hydrocarbon groups and aromatic hydrocarbon groups can be mentioned.
[0086]
Examples of the hydrophobic monomer include aliphatic hydrocarbons and aromatic hydrocarbons having a polymerizable double bond. The alkene, diene or styrene having a carbon number of preferably 4 to 20, more preferably 5 to 10. And derivatives thereof. In the copolymer, at least one of the hydrophobic monomers may be copolymerized, and two or more of them may be copolymerized.
More specifically, for example, styrene, α-methylstyrene, α-ethylstyrene, and the like are preferable. Of these, styrene, α-methylstyrene, and derivatives thereof are preferable because they have high hydrophobization efficiency and good precipitation efficiency, and excellent controllability when copolymerizing with a hydrophilic monomer.
[0087]
These hydrophobic monomers may be those obtained by substituting at least some of the hydrogen atoms in the molecule with deuterium atoms, as described above. The copolymer obtained by polymerizing at least a hydrophilic monomer and a hydrophobic monomer is preferably a copolymer obtained by polymerizing at least styrene or a derivative thereof and (meth) acrylic acid as a monomer.
[0088]
The plastic monomer constituting the copolymer has the properties of electrodeposition film formation as described above and the property of suppressing film quality deterioration after the electrodeposition film formation, and at least the plastic group is necessarily present in the molecule. It is what has.
[0089]
The plastic monomer preferably has a glass transition point in the range of −125 ° C. to 50 ° C. when it is made into a homopolymer state, imparts appropriate rigidity to the electrodeposition film, and cracks the electrodeposition film. The glass transition point is more preferably in the range of −80 ° C. to 25 ° C. in terms of imparting plasticity that is difficult to occur.
When the glass transition point is less than −125 ° C., the electrodeposition film becomes too soft, and when it exceeds 50 ° C., an electrodepositable polymer material obtained by copolymerization using this plastic monomer. In some cases, cracks are likely to occur in the electrodeposited film comprising.
Specific characteristics of the plastic monomer in terms of the molecular structure are preferably those having an ester group in the molecule, but are not limited thereto, and may have any of the above characteristics. There is no particular limitation.
[0090]
Specific examples of the plastic monomer include monomers containing an ester group as described above, and preferred examples include methacrylic acid esters, acrylic acid esters, maleic anhydride esters, and derivatives thereof. It is done. In particular, when the plastic monomer is composed of methacrylic acid esters, the ester has preferably 1 to 20 carbon atoms, more preferably 2 to 10 carbon atoms. When the plastic monomer is composed of acrylic acid esters, the ester carbon number is 1-20 are preferable, and 2-9 are more preferable. Further, in the copolymer, at least one of the hydrophobic monomers may be copolymerized, and two or more of them may be copolymerized.
[0091]
Examples of the methacrylic acid esters and derivatives thereof include ethyl methacrylate and butyl methacrylate. Examples of the acrylate esters and derivatives thereof include methyl acrylate, ethyl acrylate, butyl acrylate, and acrylic. Examples include acid-n-hexyl and 2-ethylhexyl acrylate. Examples of maleic anhydride esters and derivatives thereof include methyl maleic anhydride and ethyl maleic anhydride.
[0092]
In addition, as described above, these plastic monomers may be those in which at least a part of hydrogen atoms in the molecule is substituted with deuterium atoms.
[0093]
From the above, from the viewpoint of steep change in state due to pH change and high hydrophilicity, as monomers constituting the copolymer, styrene and its derivatives, (meth) acrylic acid and its derivatives, and ester group-containing monomers Is particularly preferred as a copolymer component.
[0094]
In addition, it can also be set as the copolymer formed by superposing | polymerizing by adding another monomer to said 2 type or 3 types of monomer.
Examples of such a monomer include a monomer having a crosslinkable group. A copolymer obtained by polymerization using a monomer having such a crosslinkable group can be formed by cross-linking individual electrodepositable polymers by performing a heat treatment after forming an electrodeposition film. The mechanical strength and heat resistance of the deposited electrodeposition film can be improved.
[0095]
Examples of the crosslinkable group include an epoxy group, a blocked isocyanate group (including a group that can be changed to an isocyanate group), a cyclocarbonate group, and a melamine group.
Examples of the monomer having a crosslinkable group include glycidyl (meth) acrylate, (meth) acrylic acid azide, 2- (O- [1′-methylpropylideneamino] carboxyamino) ethyl methacrylate (Showa Denko ( Product name: Karenz MO1-BN), 4-((meth) acryloyloxymethyl) ethylene carbonate, (meth) acryloylmelamine, and the like. These crosslinkable monomers may vary depending on the type of monomer used, but are generally included in a proportion of 1 to 20 mol% of all monomers used when copolymerizing the electrodepositable polymer material. preferable.
[0096]
In addition to the monomer having a crosslinkable group, for example, in order to adjust the plasticity of the electrodeposited film, a small amount of a monomer that lowers the plasticity such as methyl methacrylate may be used as necessary. The other monomers are not limited to these examples, and monomers other than those described above can be used as necessary.
[0097]
The refractive index of the deuterium-substituted electrodepositable polymer material containing the copolymer as described above is
The range of about 1.4 to 1.6 is the same as that of ordinary polymer materials, and the composition of the electrodepositable polymer material is controlled or refracted to the electrodepositable polymer material as necessary. The desired refractive index can be adjusted by adding fine particles for controlling the refractive index.
[0098]
The electrodepositable polymer material having the characteristics as described above can be obtained by appropriately adjusting the types of hydrophilic group, hydrophobic group and plastic group, the balance of hydrophilic group and hydrophobic group, acid value, molecular weight and the like. As long as the electrodeposition polymer material contained in the electrodeposition liquid of the present invention does not impair the formation effect of the thin film, any of the materials described above can be arbitrarily combined, and two or more types of anionic molecules can be combined. A mixture of homopolar molecules, such as a mixture, or a mixture of heteropolar molecules, such as a mixture of anionic and cationic molecules.
[0099]
Next, the content of each component contained in the electrodeposition liquid will be described. The components constituting the electrodeposition liquid can be roughly classified into three types: electrodepositable polymer materials as described above, various other additives, and solvents, and are included in the electrodeposition liquid below. The contents of the electrodepositable polymer material and the solvent will be described. In addition, content (or addition amount) of various additives is mentioned later.
The content of the electrodepositable polymer material contained in the electrodeposition liquid is preferably 0.3 to 25% by mass, and more preferably 1.2 to 12% by mass. When the content is less than 0.3% by mass, the film formability is lowered and becomes unstable, and the film property may be inferior. When the content exceeds 25% by mass, the viscosity of the electrodeposition liquid increases. May cause manufacturing problems such as replenishment.
[0100]
As the solvent, at least one kind of water and / or a water-soluble solvent (hereinafter sometimes abbreviated as “water-soluble solvent”) is used, and the content of these solvents contained in the electrodeposition liquid is 60 It is preferable that it is -98 mass%, and it is more preferable that it is 75-95 mass%.
However, in the said range, it is preferable that content of the water contained in an electrodeposition liquid is 25-83 mass%, and it is more preferable that it is 55-75 mass%. Moreover, it is preferable that content of the water-soluble solvent contained in an electrodeposition liquid is 0.5-25 mass%, and it is preferable to exist in the range of 2.2-7 mass%.
[0101]
The water-soluble solvent means a water-soluble liquid having a boiling point of 110 ° C. or higher and a vapor pressure of 100 mHg (13.33 KPa) or lower at room temperature (20 ° C.). More preferably, the boiling point is 150 ° C. or higher and the vapor pressure at room temperature (20 ° C.) is 60 mHg (8.0 KPa) or lower.
Such a water-soluble solvent is not particularly limited as long as it satisfies the above conditions. For example, dimethylaminoethanol, ethylene glycol, diethylene glycol, polyethylene glycol, glycerin, ethyl cellosolve, methyl cellosolve, ethylene glycol mono Examples include ethyl ether and ethylene glycol dimethyl ether.
[0102]
The electrodeposition high molecular material has a liquidity change that causes precipitation by generating a supernatant from a dissolved state or a dispersed state in accordance with a change in pH value of an electrodeposition solution in which the electrodepositable polymer material is dissolved. It preferably occurs within 9, more preferably within 1.5.
When the pH range is within 2.9, the film can be deposited instantly even when a sharp pH change is caused by energization, and the cohesive strength of the deposited film is high, so that the film is re-dissolved in the electrodeposition liquid. The effect of reducing the speed is excellent. When the pH range exceeds 2.9, the film deposition rate for obtaining a film having a sufficient thickness is likely to decrease, or the water resistance of the film is lacking.
[0103]
Furthermore, the electrodeposition liquid in a state where the electrodepositable polymer material is dissolved has characteristics that it is difficult to re-dissolve in addition to a sharp change in state that causes precipitation with respect to a change in pH value. It is preferable. This characteristic is a so-called hysteresis characteristic. For example, in the case of an anionic electrodeposition material, precipitation occurs rapidly due to a decrease in pH, but even if the pH increases (for example, at the end of electrodeposition, that is, voltage application). It means that re-dissolution does not occur abruptly and the precipitation state is maintained for a certain period of time. On the other hand, those that do not exhibit hysteresis characteristics have increased solubility even when the pH is slightly increased, and the deposited film tends to be redissolved.
[0104]
Also, if electrodeposition is performed under conditions such that the solubility of the electrodepositable polymer is saturated before the thin film is formed, it is difficult to redissolve after the thin film is formed. However, in the photodeposition method described later, when a film is formed at the pH of an unsaturated solution, the film starts to dissolve again as soon as light irradiation is stopped, even if a thin film is formed. Therefore, it is desirable to form the thin film at a pH of the solution that saturates the solubility, and therefore it is necessary to adjust the electrodeposition solution using acid or alkali at the desired pH.
[0105]
The pH adjusting agent that adjusts the pH of the electrodeposition liquid is an inorganic alkali agent--for example, a water-soluble sodium compound or lithium compound, because silicon-based electronic components such as thin film transistors may exist on the substrate used for electrodeposition. Alternatively, potassium compounds and the like are difficult to use because they react with the silicon material and impair electronic device characteristics.
Therefore, in such a case, it is preferable to use ammonium compounds such as quaternary ammonium compounds and tetraalkylammonium compounds, and saturated or unsaturated amines. Even if such a compound is present in the electrodeposition liquid, it does not adversely affect the characteristics of silicon-based electronic components such as thin film transistors.
[0106]
Examples of the ammonium compound include ammonia water, tetraethylammonium perchlorate, tetramethylammonium perchlorate, tetrapropylammonium perchlorate, triethylpropylammonium perchlorate, methyltriethylammonium hydroxy, tetramethylammonium hydroxy, tetraethylammonium hydroxy. Etc. Examples of the amines include methylaminoethanol, dimethylaminoethanol, ethylaminoethanol, ethylenediamine, propylenediamine, methylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, propylamine, dipropylamine, and butylamine. And pentylamine. These pH adjusters may be used alone or in combination of two or more.
[0107]
In addition, since there is a possibility that the material system may be adversely affected by concentration of the liquid that remains attached after film formation, it is preferable to remove the pH adjuster as a post-treatment before the manufacturing process is completed. Therefore, by using a pH adjuster having a boiling point of 200 ° C. or less, the removal efficiency is high by simple heat treatment, and the pH adjuster can be easily removed. Therefore, the organic material of the pH adjuster includes, for example, an ammonium compound, an amine compound, a quaternary ammonium compound, and the specific examples are organic pH adjusters and have a boiling point of 200 ° C. or less, preferably It is preferable to use a material in the range of 50 ° C to 160 ° C. Those having a temperature of 50 ° C. or less are highly likely to evaporate from the liquid in a gas state at all times, causing a problem in the stability of the pH of the electrodeposition solution, and those having a boiling point higher than 200 ° C. The difficulty increases, the efficiency of removal from the electrodeposition film decreases, and the heat treatment temperature increases, resulting in a large risk in the removal process.
[0108]
The concentration of the pH adjusting agent contained in the electrodeposition liquid is preferably in the range of 5 mmol / liter to 50 mol / liter, more preferably in the range of 20 mmol / liter to 5 mol / liter, and 50 mmol / liter. A range of from 1 to 0.5 mol / liter is particularly preferred.
[0109]
Next, the conductivity of the electrodeposition liquid will be described. The conductivity is related to the amount of electrodeposition per unit time (electrodeposition film formation rate). The higher the conductivity, the thicker the electrodeposition film deposited in a certain time, and the amount of electrodeposition is It tends to saturate at about 1 mS / cm or less.
In consideration of the balance between the electrodeposition film formation speed and the controllability at the time of electrodeposition film formation, the conductivity of the electrodeposition liquid is preferably within the range of 0.1 mS / cm to 100 mS / cm, and 1 mS / cm to 15 mS. More preferably within the range of / cm. When the conductivity of the electrodeposition liquid is less than 0.1 mS / cm or less, a sufficient current cannot be obtained, so the electrodeposition film formation rate becomes too low, and the electrodeposition film having a desired film thickness is not obtained. It may take time to form. Moreover, when it is larger than 100 mS / cm, the controllability of the electrodeposition amount may be deteriorated.
[0110]
If the conductivity of the electrodeposition liquid is insufficient, ions that do not affect electrodeposition, such as NH⁴⁺The rate of electrodeposition film formation can be controlled by adding ions or Cl- ions to the electrodeposition solution. Usually, the electrodeposition liquid increases the conductivity by adding a supporting salt. Commonly used supporting salts in electrochemistry are alkali metal salts such as NaCl and KCl, ammonium chloride, ammonium nitrate, tetraethylammonium perchlorate (Et_FourNClO_Four) And the like are used. These supporting salts can also be used in the present invention.
[0111]
Since the electrodepositable polymer material described above has the optical characteristics as described above, it is suitable as a material for forming an optical component such as an optical waveguide.
In addition, ultraviolet rays are not absorbed even when dissolved in water as an electrodeposition solution, so that the patterned semiconductor can be irradiated with pattern ultraviolet rays through the electrodeposition solution. Furthermore, since it can be electrodeposited at a low potential, the amount of oxygen gas generated at the time of film formation is small, so that the generated oxygen dissolves and the film surface is maintained smooth without causing a large bubbling phenomenon. An electrodeposition pattern can be formed by photovoltaic power generated by an optical semiconductor.
The potential at the time of electrodeposition is not particularly limited, but is preferably 9 V or less, and more preferably 4 V or less.
[0112]
The deposition film material used for electrodeposition is preferably a conductive material, or a layer made of a conductive material is preferably provided on the surface of the deposition film material on which the electrodeposition film is formed. Further, it is more preferable that the conductive material also serves as an anode electrode.
Such a conductive material is not particularly limited as long as it has conductivity. For example, iron and its compound material, nickel and its compound material, zinc and its compound material, copper and its compound material, titanium and The compound material, chromium, its compound, etc. can be used, and what contains 2 or more types other than what contains 1 type of these materials can be used.
[0113]
Next, the case where a core layer and a clad layer are formed using an electrodepositable polymer material will be described. In this case, a method for causing a difference in refractive index between the core layer and the clad layer is as follows.
(1) As the electrodeposition liquid for the clad layer, the one containing the electrodeposition polymer as described above is used. On the other hand, as the electrodeposition liquid for core formation, in addition to the electrodeposition polymer, the electrodeposition high Use is made by dispersing fine particles having a higher refractive index than molecules.
(2) An electrodeposition liquid containing the above-mentioned electrodeposition polymer is used as the core layer electrodeposition liquid. On the other hand, as the electrodeposition liquid for clad formation, in addition to the electrodeposition polymer, the electrodeposition high Use is made by dispersing fine particles having a lower refractive index than molecules.
(3) The core layer electrodeposition liquid is obtained by dispersing fine particles having a refractive index higher than that of the electrodepositable polymer in addition to the above electrodepositable polymer, and the clad layer electrodeposition liquid. In addition to the electrodepositable polymer, a dispersion in which fine particles having a refractive index lower than that of the electrodepositable polymer is used.
(4) As the electrodeposition liquid for the clad layer, the one containing the electrodeposition polymer as described above is used. On the other hand, as the electrodeposition liquid for core formation, the electrodeposition liquid having a higher refractive index than the electrodeposition polymer is used. Uses dispersed molecules.
[0114]
The difference in refractive index between the core layer and the cladding layer as described above uses two types of electrodepositable polymer materials having different refractive indexes and / or electrodeposited polymer materials to which fine particles for adjusting the refractive index are added. It is possible to adjust by using as appropriate.
Next, the fine particles for adjusting the refractive index of the core layer and / or the clad layer added to the electrodeposition solution will be described. The number average particle diameter of the fine particles is preferably 0.2 to 150 nm, more preferably 20 to 85 nm, from the viewpoint of dispersibility in the electrodeposition liquid and transparency of the electrodeposition film. If the number average particle diameter is less than 0.2 nm, the cost during production increases, and stable quality may not be obtained. 150 nm (that is, the longest in the wavelength range used for communication). If it exceeds 1/10 of the wavelength band of 1.5 μm, depending on the wavelength band to be used, transparency may be deteriorated and internal irregular reflection may be caused, and internal loss may increase.
[0115]
The addition amount of these fine particles to the electrodeposition liquid is preferably in the range of 0.5 to 25% by mass, and more preferably in the range of 1.2 to 6% by mass. When the addition amount is less than 0.5% by mass, a difference in refractive index between the core layer and the clad layer may not be obtained. On the other hand, when the amount is more than 25% by mass, the viscosity of the electrodeposition liquid in which the fine particles are dispersed increases and the thixotropy increases, and the electrodeposition liquid is transported and supplied during electrodeposition. Problems may occur in terms of agitation, uniformity, flow path resistance, and the like.
[0116]
Examples of the high refractive index fine particles added to the core layer electrodeposition liquid include titanium oxide and zinc oxide. Examples of the low refractive index fine particles added to the clad layer electrodeposition liquid include fluorine compounds such as magnesium fluoride. Materials.
[0117]
Next, regarding the removal of the unnecessary electrodeposition liquid on the electrodeposition substrate after electrodeposition, an unnecessary electrodeposition liquid adheres to various places on the electrodeposition substrate immediately after electrodeposition. In order to remove the unnecessary electrodeposition liquid with high integrity, washing off by liquid washing is an effective means. In particular, cleaning with an inert liquid that is transparent and highly safe is effective. However, since it is immediately after electrodeposition, the electrodeposited film is short of strength both physically and chemically.
[0118]
For this reason, it becomes an effective method to wash off the electrodeposited film with a cleaning liquid in which solidification is further promoted while cleaning and removing unnecessary liquid. As an effective liquid, an aqueous liquid having a pH value that is more likely to precipitate than the deposition start pH value of the electrodeposition liquid, that is, the electrodeposition film itself is brought into contact with this liquid, so that solidification is promoted and unnecessary. The colorant components of the electrodeposition liquid aggregate and lose adhesion, and are easily washed off. A cleaning solution using this phenomenon is a very effective means for this post-processing step. As a result, the pH value inside the electrodeposition film is also lower than that during electrodeposition. Of course, the electrodeposition film is on the deposition side from the deposition starting pH value of the electrodeposition liquid, and it is more robust and has higher resolution and finer. A simple pattern can be formed. In order to further enhance the effects of cleaning of the cleaning liquid and hardening of the film, it is preferable to set the pH value to a value at which it is more likely to precipitate 0.3 or more than the deposition starting point pH value of the electrodeposition liquid. On the other hand, when the value is 1.5 or more, re-dissolution of the deposited film occurs remarkably.
[0119]
(Electrodeposition method)
Using the electrodeposition liquid of the present invention as described above, JP-A-10-119414, JP-A-11-189899, JP-A-11-15418, JP-A-11-174790, JP-A-11- An electrodeposition film can be formed on a substrate by using an electrodeposition method or a photoelectrodeposition method described in JP-A No. 133224, JP-A No. 11-335894, or the like. Therefore, it is possible to create an optical component such as an optical waveguide having desired optical characteristics.
[0120]
Basically, the electrodeposition method is a method in which a patterned conductive thin film is provided on an insulating substrate, and the solubility or dispersibility in an aqueous liquid is reduced by changing the pH value by electrolysis of water. A voltage is applied between the conductive thin film and the counter electrode in an aqueous electrodeposition liquid containing a film-forming material to be disposed so that at least the conductor thin film is in contact with the electrodeposition liquid, and the conductive In this method, the material is deposited on a thin film.
[0121]
In addition, the photo-deposition method uses a photovoltaic force generated in a photo-semiconductor thin film, and a conductive thin film and a photo-semiconductor thin film stacked in this order on an insulating substrate are subjected to an aqueous liquid by changing pH. Irradiating a selected region of the optical semiconductor thin film with a water-based electrodeposition liquid containing a film forming material whose solubility or dispersibility is lowered, with at least the optical semiconductor thin film being in contact with the electrodeposition liquid. Thus, a voltage is applied between the photo-semiconductor thin film and the counter electrode in the selected region, and the material is deposited in the selected region of the semiconductor thin film.
[0122]
By using these various electrodeposition methods and photodeposition methods, electrodeposition can be performed at a low potential of 4.5 V or less, preferably 3.5 V or less without applying a voltage higher than 9 V, and a thin film is formed. Because there is little energizing current, the generated oxygen gas dissolves almost in the electrodeposition station, and good high film properties are obtained without producing foam marks on the surface of the thin film due to foaming during electrodeposition. I can do it. Thereby, a fine pattern can be formed with high accuracy.
[0123]
Moreover, in the conventional pattern forming method using a photosensitive resin, the film thickness of the photosensitive resin is accurately controlled on the substrate and applied to one surface, and then a large amount of an alkaline solution is developed through an exposure process. The pattern of the optical waveguide is formed through a step of using and developing. However, since the alkaline solution used for development is all a waste solution, there is a problem in the environment, technology, and cost, such as a large burden on the environment and a complicated and long pattern accuracy and process.
However, the film thickness can be easily controlled by adjusting the light irradiation time or voltage application time, and the etching process using a developer for pattern formation is unnecessary and the load on the environment is small. In terms of environment, technology and cost.
[0124]
On the other hand, an attempt has been made to fabricate an element in which an electronic circuit and an optical circuit are mixedly mounted on a substrate. However, in the conventional method, a circuit formed first is etched by patterning of a circuit to be formed next. There was a risk of injury. However, such a problem can be avoided because there is no etching process in the pattern forming method by the photo-deposition method.
As described above, the method for forming a fine pattern by the electrodeposition method or the photo-deposition method described above using the electrodeposition liquid of the present invention is a simple method and a method with a low environmental load. For this reason, for the production of optical components such as various optical waveguides, optical integrated circuits, and optical wiring boards used in the fields of general optics and micro-optics that require high precision and high productivity, and the fields of optical communication and optical information processing. It is advantageous.
[0125]
Note that the substrate used for manufacturing an element provided with both an electronic circuit and an optical circuit on the substrate is not particularly limited, but a semiconductor or the like is processed in advance on at least the surface on which the electrodeposition film is formed. Various electronic circuits formed in this manner may be provided. Alternatively, at least the surface on which the electrodeposited film is formed is covered with a material capable of forming an electronic circuit, such as a semiconductor material such as a crystalline, microcrystalline, or amorphous silicon material, or a metal material. It may be.
[0126]
Next, a case where an electrodeposition film is formed by a photodeposition method using the electrodeposition liquid of the present invention will be described by taking as an example a case where an optical waveguide is formed by forming an electrodeposition film on a substrate.
The substrate for optical waveguide fabrication used in the pre-photodeposition method (hereinafter referred to as “optical waveguide fabrication substrate”) is obtained by laminating a conductive thin film and an optical semiconductor thin film in this order on an insulating substrate. As the substrate, a glass plate, a quartz plate, a plastic film, an epoxy substrate, etc., the conductive thin film is ITO, indium oxide, nickel, aluminum, etc., and the optical semiconductor thin film will be described in detail later, For example, a titanium oxide thin film is used. In the case where light is applied to the optical semiconductor thin film through the insulating substrate, the insulating substrate and the conductive thin film must be light transmissive. However, this does not apply when light is irradiated through the electrodeposition solution.
[0127]
The “selection region” described above refers to not only a partial region of the optical waveguide production substrate but also a whole region when an optical waveguide is produced by the photo-deposition method using the electrodeposition liquid of the present invention. For example, when the clad layer is formed on the entire surface of the substrate, it means that the entire surface is irradiated with light or a uniform bias voltage is applied to the entire surface. A core layer and / or a clad layer can be produced by such a method.
[0128]
When the clad layer and the core layer are formed on the substrate by using the electrodeposition liquid of the present invention, the clad layer is formed using the clad forming electrodeposition liquid, and then the formed clad layer is dried. Instead, the core layer can be formed using the electrodeposition liquid for core formation. Of course, the reverse is also true.
Further, when a clad layer-core layer-cladding layer laminate is formed, the clad forming electrodeposition solution is used to dry the clad layer and core layer formed as described above without drying them. Further, a cladding layer can be formed.
[0129]
When moisture is removed after drying, the clad layer or core layer is insulative, so that the core layer or clad layer cannot be overlaid by the photo-deposition method. The conductivity of the electrodeposition film can be maintained, and another layer can be laminated on the core layer or the clad layer.
[0130]
When the clad layer and the core layer are laminated by the method of the present invention and the clad layer is formed on the entire surface, first, the clad forming electrodeposition solution is used, and the optical waveguide production substrate or After the clad layer is formed by irradiating light onto the selected region (entire surface) of the deposition substrate, the core forming electrodeposition solution is used to dry the clad layer without drying the formed clad layer. A core layer can be formed by light irradiation.
[0131]
Further, without drying the clad layer and the core layer formed as described above, the clad forming electrodeposition solution is used to irradiate the entire surface with light or apply a bias voltage to the entire surface of the core layer. Furthermore, a clad layer can also be formed (lower clad layer / core layer / upper clad layer structure).
Furthermore, when forming the cladding layer, it is possible to electrodeposit the cladding layer by applying a voltage exceeding the Schottky barrier of the optical semiconductor thin film of the optical waveguide fabrication substrate without irradiating light. is there. In this method, the exposure process can be omitted, and the method becomes simpler.
[0132]
Next, an optical semiconductor thin film used for the photo-deposition method will be described. As the optical semiconductor thin film used for the photo-deposition method, basically, any transparent thin film semiconductor that generates an electromotive force by light irradiation can be used.
Specifically, the semiconductor includes GaN, diamond, c-BN, SiC, ZnSe, TiO.₂One or more types such as ZnO are contained. Of these, titanium oxide is preferably used because its absorption is only 400 nm or less.
[0133]
As a method of providing a titanium oxide semiconductor thin film on a substrate, there are a thermal oxidation method, a sputtering method, an electron beam evaporation method (EB method), an ion plating method, a sol-gel method, and the like. As a result, a product with good characteristics can be obtained.
However, when the substrate has a low heat resistance, for example, a plastic film, or when an optical waveguide is formed on a substrate provided with TFTs, a film forming method that does not adversely affect the plastic film or TFT is selected. There is a need. The sol-gel method can form titanium oxide having high optical activity as an optical semiconductor. However, since it is necessary to sinter at around 500 ° C., when using a plastic film substrate having only heat resistance of about 200 ° C., or 250 ° C. It is difficult to produce a titanium oxide film on a substrate provided with a TFT that cannot be heated as described above.
[0134]
However, in the case of using a plastic film substrate, it is possible to form a film at 200 ° C. or less if possible at a temperature as low as possible, and a sputtering method, particularly an RF sputtering method, which is a film forming method with relatively little damage to the substrate. Preferably used. When using a substrate provided with a TFT, a laser annealing method, an electron beam heating method, or a coating solution for forming a thin film in which photocatalytic titanium oxide fine particles are dispersed (TOTO Corporation or Nippon Soda Co., Ltd.) Etc.) (e.g., lift-off method using a photoresist), and a method of forming a titanium oxide thin film at a low temperature is applied.
[0135]
In order to form an anatase-type titanium oxide thin film with high optical activity, it is preferable to use an RF sputtering method, and this method is easy to obtain a relatively high photovoltaic power.
The thickness of the optical semiconductor thin film is in the range of 0.05 μm to 3 μm in which good characteristics are obtained. If the thickness is less than 0.05 μm, light absorption tends to be insufficient, and a sufficient photocurrent cannot be obtained. On the other hand, if it exceeds 3 μm, the film forming property such as cracks in the film tends to be deteriorated, so the above range is appropriate. When the optical semiconductor thin film is titanium oxide or zinc oxide, a substrate having the optical semiconductor thin film on the surface can be produced by oxidizing the titanium or zinc plate as described above.
[0136]
Next, a method for producing an optical waveguide using an electrodeposition method will be described. In this method, a substrate for producing an optical waveguide in which a conductive thin film or a patterned conductive thin film is provided on an insulating substrate is used, and the solubility or dispersibility in an aqueous liquid is lowered by changing the pH. A voltage is applied between the conductive thin film and the counter electrode in an aqueous electrodeposition liquid containing a film forming material so that at least the conductive thin film is in contact with the electrodeposition liquid, and the conductive thin film The material is deposited on the substrate. As the insulating substrate, the same one as in the case of the photo-deposition method can be used. The patterned conductive thin film is formed by patterning the conductive thin film by a conventional method, or by applying an insulating film leaving only a necessary portion on the conductive substrate and exposing the patterned conductive portion. May be used. Using these substrates, a clad layer or a core layer can be produced by an electrodeposition method.
[0137]
Next, the electrodeposition apparatus used when producing by the photo-deposition method and the electrodeposition method will be described.
In the photo-deposition method, the method of selectively irradiating light to the optical semiconductor thin film is not particularly limited. In addition to the method using a photomask, laser exposure may be mentioned. It is preferable to use a mask.
[0138]
FIG. 1 is a conceptual diagram showing an example of an electrodeposition apparatus using a projection exposure apparatus, which is used when manufacturing an optical waveguide. The electrodeposition apparatus of FIG. 1 uses a photomask and forms an optical waveguide by a photo-deposition method. The electrodeposition apparatus shown in FIG. 1 includes a light source (not shown) for irradiating ultraviolet rays, an imaging optical system having a first imaging optical lens 72 and a second imaging optical lens 73, a first A photomask 71 inserted between the imaging optical lens and the second imaging optical lens, an electrodeposition tank 80 containing an electrodeposition solution, a means 90 for applying voltage such as a potentiostat, a counter electrode 91, a saturated calomel A reference electrode 92 such as an electrode is provided.
[0139]
In the electrodeposition apparatus, a mirror reflection optical system can be used instead of the imaging optical system. And as shown in FIG. 1, the optical waveguide production board | substrate is arrange | positioned and used for the said electrodeposition apparatus in an electrodeposition tank. By using the projection optical system as described above, pattern exposure can be imaged on the optical semiconductor thin film, and the resolution of the optical waveguide can be improved in a short exposure time.
[0140]
The distance between the imaging optical lens of the imaging optical system and the light-transmitting substrate surface is preferably 1 mm to 50 cm from the viewpoint of handling, and the focal depth of the imaging optical system is ± 10 to ± 100 μm. This range is preferable from the viewpoint of accuracy and handling.
[0141]
In addition, when the photomask and the optical semiconductor thin film are close to each other, it is not necessary to use an apparatus having an exposure apparatus having an imaging optical system or a mirror reflection optical system as described above, but a parallel light or contact type exposure apparatus. Can be irradiated with light. As the irradiation light source, for example, a uniform irradiation light source of Hg—Xe can be used.
FIG. 2 is a conceptual diagram showing an example of an electrodeposition apparatus using a proximity exposure apparatus used when manufacturing an optical waveguide. In the electrodeposition apparatus shown in FIG. 2, the Hg—Xe uniform irradiation light source 75 is used, the photomask 71 is placed in close proximity to the liquid surface, and the optical waveguide fabrication substrate is placed near the photomask to form a fine pattern. Formation is possible. In this case, it is desirable that the water depth of the electrodeposition liquid on the optical waveguide substrate is as shallow as possible.
[0142]
In addition to this, when exposing an optical semiconductor thin film through an insulating substrate, the insulating substrate is made 0.2 mm or less to prevent light diffraction, and by exposing a photomask in close contact with the substrate, A pattern with excellent resolution can be obtained. A plastic film is suitably used as the insulating substrate of 0.2 mm or less.
[0143]
Of course, if the exposure time may be long, light irradiation can be performed by an inexpensive scanning laser writing apparatus.
FIG. 3 is a conceptual diagram showing an example of an electrodeposition apparatus using a scanning laser exposure apparatus, which is used when manufacturing an optical waveguide. The electrodeposition apparatus in FIG. 3 can irradiate a selected region with laser light. A scanning laser writing device 78 for irradiating a laser beam such as a He-Cd laser, an electrodeposition bath 80 containing an electrodeposition solution, a means 90 for applying voltage such as a potentiostat, a counter electrode 91, a saturated calomel electrode A reference electrode 92 is provided.
In addition to this, a cheaper proximity type exposure apparatus can be used as long as the pattern resolution allows.
[0144]
In the photo-deposition method, the exposure may be performed from the insulating substrate side of the optical waveguide fabrication substrate or the deposition substrate or from the optical semiconductor thin film side. In the case of exposure from the optical semiconductor thin film side, the substrate is immersed in an electrodeposition solution, but the electrodeposition solution used in the present invention does not absorb ultraviolet rays used as irradiation light. An optical semiconductor thin film can be exposed through a liquid. FIG. 1 shows the case where exposure is performed from the insulating substrate side, and FIGS. 2 and 3 show the case where exposure is performed from the optical semiconductor thin film side.
In the photo-deposition method, when an electromotive force sufficient for electrodeposition can be obtained by an optical semiconductor, it is not necessary to apply a bias voltage by a voltage application device.
[0145]
Further, FIG. 4 shows a conceptual diagram of an apparatus for producing an optical waveguide by an electrodeposition method. This apparatus includes an electrodeposition tank 80 containing an electrodeposition liquid, a means 90 for applying a voltage such as a potentiostat, and a counter electrode. A reference electrode 92 such as an electrode 91 and a saturated calomel electrode is provided. This figure shows that a conductive film is provided on the entire surface of the substrate to form a cladding layer.
In FIG. 1 to FIG. 4, the voltage application device is connected to the conductive thin film. In the photo-deposition method, the photo semiconductor thin film functions as a working electrode.
[0146]
(Optical components such as optical waveguides and manufacturing methods thereof)
Next, an optical component such as an optical waveguide produced by an electrodeposition method or a photo-deposition method using the electrodeposition liquid of the present invention described above and a method for producing the same will be described.
That is, the present invention is an optical component that transmits information using light in a wavelength range of at least 700 nm to 1350 nm and a method for manufacturing the same, and at least a part of the optical transmission portion of the optical component is the present invention. It is produced using the electrodeposition liquid. Furthermore, when forming an optical component using the electrodeposition liquid of the present invention, the optical component is more preferably an optical waveguide. The optical component is preferably a lens.
[0147]
The light transmission portion means only a portion where light is directly transmitted, and a portion that indirectly contributes to light transmission, for example, a cladding layer to prevent leakage of light transmitted through the core layer. It does not mean a part having a special function. However, the optical component obtained by the present invention is formed by using the electrodeposition liquid of the present invention as long as at least a part of the light transmission part is formed by the electrodeposition liquid of the present invention. May be. The optical component obtained by the present invention may be combined with an electrical component such as a semiconductor circuit or a laser diode and / or a photoelectric conversion component.
Accordingly, the optical component such as an optical waveguide obtained by the present invention has the optical characteristics as described above, particularly the information using infrared light because the portion formed using the electrodeposition liquid of the present invention has the optical characteristics as described above. Can be used for transmission.
[0148]
Next, an optical component obtained by the present invention and a manufacturing method thereof will be described with respect to a case where the optical component is manufactured by a photo-deposition method using an optical waveguide as an example. However, the present invention is not limited to the following examples.
[0149]
FIG. 5 is a schematic cross-sectional view showing an example of an optical waveguide manufactured according to the present invention and a process for forming the same. FIGS. 5A to 5D show a case where a cladding layer is formed on the entire surface of a substrate. The formation process of an optical waveguide is shown. FIG. 5A shows an example of an optical waveguide manufacturing substrate, 10 is an insulating substrate, 12 is a conductive film, and 14 is an optical semiconductor thin film. In FIG. 5B, the electrodeposition liquid for the clad layer is used on the optical semiconductor thin film, and the entire surface is irradiated with light, or a voltage exceeding the Schottky barrier of the optical semiconductor thin film is applied without light irradiation. It is a figure which shows the state which formed the clad layer 16 (undried state) by.
[0150]
FIG. 5C shows a state in which the core layer 18 is formed in the selected region by irradiating the selected region with light using the core layer electrodeposition liquid on the clad layer in an undried state. FIG. 5D shows a Schottky barrier that the photo semiconductor thin film has on the undried core layer 18 by using a clad layer electrodeposition solution or with or without light irradiation on the entire surface. It is a figure which shows the state which formed the clad layer 20 (undried state) by applying the voltage exceeding. Thereafter, each layer is dried to form an optical waveguide. In this manner, an optical waveguide can be manufactured as shown in FIG.
[0151]
Next, another optical waveguide manufactured according to the present invention when the cladding layer is not formed on the entire surface of the optical waveguide manufacturing substrate, and the process of forming the optical waveguide will be described with reference to the drawings.
FIG. 6 is a schematic cross-sectional view showing another example of an optical waveguide manufactured according to the present invention and its formation process. FIGS. 6A to 6E show a clad layer provided on the entire surface of a substrate. The formation process of the optical waveguide when it is not done is shown. FIG. 6A shows an optical waveguide manufacturing substrate similar to that shown in FIG. FIG. 6B is a diagram showing a state in which the lower clad layer 16 (undried state) is formed by using the electrodeposition liquid for the clad layer on the optical semiconductor thin film and irradiating the selected region with light.
[0152]
FIG. 6C shows a state in which the core layer 18 is formed in the selected region by irradiating the selected region with light using the core layer electrodeposition liquid on the undried lower clad layer 16. . FIG. 6D is a diagram in which the side cladding layer 17 is formed on the side surface of the core layer 18 in an undried state by using the electrodeposition liquid for the cladding layer and irradiating the selected region with light. Further, FIG. 6E is a diagram in which the upper clad layer 20 is formed on the clad layer 17 and the core layer 18 in an undried state by using a clad layer electrodeposition solution and irradiating a selected region with light. is there. In this way, an optical waveguide as shown in FIG. 6E can be obtained.
[0153]
In this aspect, an optical functional component such as an optical waveguide or a microlens array can be formed in a portion where no clad layer is present on the optical waveguide fabrication substrate by further performing a similar photoelectric deposition process. Furthermore, since the obtained optical waveguide has high accuracy and the upper portion of the optical waveguide is flat, it is easy to provide an optical functional component on the upper portion of the optical waveguide with high accuracy by a separate process.
[0154]
Moreover, in the said photoelectric deposition method, you may use what provided the optical-semiconductor thin film on the electroconductive board | substrate as an optical waveguide preparation board | substrate. As a material for the conductive substrate, at least one selected from iron and its compounds, nickel and its compounds, zinc and its compounds, copper and its compounds, titanium and its compounds, and mixed materials thereof can be used. In addition to this, a conductive plastic film can also be used as the conductive substrate.
[0155]
When the optical semiconductor is titanium oxide or zinc oxide, the optical semiconductor thin film is formed on the surface of the plate by oxidizing the surface of the metal titanium or metal zinc plate in addition to the method described below. Can do. In this case, the optical waveguide fabrication substrate or the deposition substrate is composed of a conductive substrate and an optical semiconductor thin film thereon.
[0156]
For the oxidation treatment, an inexpensive method such as high-temperature heat treatment in air or anodization treatment can be used, and a light-transmitting semiconductor thin film can be formed without using an expensive sputtering method. It should be noted that it is desirable to perform an insulating film treatment on the portion of the base metal substrate that has not been oxidized to avoid unnecessary electrodeposition film formation.
[0157]
Next, a method for producing an optical waveguide using an electrodeposition method will be described. In this method, a substrate for producing an optical waveguide in which a conductive thin film or a patterned conductive thin film is provided on an insulating substrate is used, and the solubility or dispersibility in an aqueous liquid is lowered by changing the pH. A voltage is applied between the conductive thin film and the counter electrode in an aqueous electrodeposition liquid containing a film forming material so that at least the conductive thin film is in contact with the electrodeposition liquid, and the conductive thin film The material is deposited on the substrate.
[0158]
As the insulating substrate, the same one as in the case of the photo-deposition method can be used. The patterned conductive thin film is formed by patterning the conductive thin film by a conventional method, or by applying an insulating film leaving only a necessary portion on the conductive substrate and exposing the patterned conductive portion. May be used. Using these substrates, a clad layer or a core layer can be produced by an electrodeposition method.
[0159]
Note that the wet electrodeposition film deposited from the electrodeposition liquid has mist-like moisture adsorbed on the surface thereof or contains moisture in the film. Since such residual moisture causes a decrease in light transmittance of the optical component, it is practically preferable that the adsorption and contained moisture be removed by heat treatment.
In addition, if drying is performed with the mist adhering to the deposited electrodeposition surface remaining, the smoothness of the electrodeposited film surface after drying will be impaired, so electrodeposition using water washing, air blow, etc. It is practically preferable to perform heat treatment after removing mist from the film surface.
[0160]
In addition, the drying process for drying the wet electrodeposition film by heat treatment is simply to remove unnecessary residual moisture, and the shape of the formed electrodeposition film is deformed or altered. It is necessary to avoid that as much as possible. That is, it is necessary to perform the heat treatment in a temperature range that does not cause the decomposition point, large deformation, or alteration of the material forming the electrodeposition film.
In this respect, it is desirable that the heat treatment temperature be within a range of ± 15 ° C. of the glass transition point (Tg), which is an electrodepositable polymer material that is a main component of the electrodeposition film. When heat treatment is performed at a temperature higher than the glass transition point + 15 ° C. of the electrodepositable polymer material, the electrodeposition film may be deformed or altered after drying. On the other hand, at a temperature lower than −15 ° C., the time required for drying may be longer than necessary. In addition, there may be micropores in the wet electrodeposition film, but these micropores can be eliminated by heat treatment within the range of ± 15 ° C of the glass transition point (Tg). Is possible.
[0161]
In addition, when the electrodepositable polymer material which is the main component of the electrodeposition film does not have a clear glass transition point, or when two or more different electrodeposition polymer materials having different glass transition points are used In such a case, the heat treatment temperature is selected so that the shape of the electrodeposition film is not deformed or deteriorated, preferably in the range of 60 to 200 ° C., more preferably in the range of 80 to 120 ° C. It is preferable to do.
When the temperature exceeds 200 ° C., most electrodepositable polymer materials may be deformed or altered, and as a result, the electrodeposition film may be deformed or altered after drying. Moreover, since it may reach close to 5,60 ° C. even under a normal use environment of the optical component, it is not preferable to perform the heat treatment at a temperature lower than 60 ° C. However, when heat treatment can be performed only at a relatively low temperature, a method of drying under reduced pressure at a low temperature or drying for a long time can be used.
[0162]
Also, when a high boiling hydrophilic solvent having an azeotropic point is used as the electrodeposition liquid, of course, the temperature during the heat treatment is selected so as not to cause deformation of the electrodeposition film as described above. However, it is effective to heat the electrodeposition film after deposition at a relatively high temperature for a long time.
[0163]
Next, a method for transferring the optical waveguide formed as described above to another substrate will be described.
First, a method for transferring an optical waveguide produced by the above-described photo-deposition method to an optical waveguide substrate will be described. The optical waveguide produced by the photo-deposition method, the core layer alone or the clad layer alone, or the clad layer and the core layer can be transferred to another substrate. As this substrate, a substrate that also functions as a cladding layer can be used.
[0164]
By doing in this way, the total number of processes including an electrodeposition process can be reduced. However, if the core layer and the cladding layer are separately formed by electrodeposition and the optical waveguide is formed by repeating the transfer, the transfer is repeated, so the loss of the interface between the core layer and the cladding layer and the optical waveguide shape The possibility of collapse is slightly increased.
[0165]
As the optical waveguide substrate, a commonly used glass substrate or epoxy substrate can be used, and as an optical waveguide substrate that also functions as a cladding layer, polyolefin films such as polyethylene, polyester films, polycarbonate films, acrylic resins A film, a fluorinated polymer film, or the like can be used.
[0166]
Next, another optical waveguide manufactured according to the present invention in the case where the optical waveguide thus formed is manufactured by a method of transferring to another substrate, and the formation process thereof will be described with reference to the drawings.
FIG. 7 is a schematic cross-sectional view showing another example of an optical waveguide manufactured according to the present invention and its formation process. FIGS. 7A to 7F show a case where an optical waveguide once formed is transferred to another substrate. This shows a forming process for producing an optical waveguide.
FIG. 7A shows an example of a deposition substrate, where 10 is an insulating substrate, 12 is a conductive thin film, 14 is an optical semiconductor thin film, and 13 is a release layer. Using this deposition substrate, as described with reference to FIGS. 6B to 6E, the lower cladding layer 16, the core layer 18, the side cladding layer 17, and the upper cladding layer 20 are formed (FIG. 7B). Next, the substrate 30 is placed on the upper clad layer 20 and subjected to heat and pressure treatment. Then, it peels between a peeling layer and a lower clad layer, and is set as an optical waveguide (refer FIG.7 (F)). In this manner, an optical waveguide as shown in FIG. 7F can be manufactured.
[0167]
Also, the clad layer or core layer produced by the electrodeposition method can be transferred to another substrate. At this time, it is advantageous to use a substrate having the function of a clad layer.
Next, the case where a core layer is formed by electrodeposition and transferred onto a substrate that also functions as a cladding layer will be described with reference to the drawings.
FIG. 8 is a schematic cross-sectional view showing another example of an optical waveguide manufactured according to the present invention and its formation process. FIGS. 8A to 8D show a core layer formed by an electrodeposition method. This shows the process of forming an optical waveguide by transferring the film onto a substrate that also functions as a cladding layer.
[0168]
In FIG. 8A, 10 is an insulating substrate, 12 is a patterned conductive thin film, and 13 is a release layer. Next, a core layer 18 is formed on the patterned conductive thin film 12 as described above (see FIG. 8B), and a substrate 32 that also functions as a cladding layer is obtained on the obtained core layer. Overlap and heat and pressure treatment are performed, and then peeling is performed between the peeling layer and the core layer (see FIG. 8C). Thereafter, a substrate 34 that also functions as another clad layer is overlaid on the surface of the core layer 18 and subjected to heat and pressure treatment in the same manner to form an optical waveguide (see FIG. 8D). In this manner, an optical waveguide as shown in FIG. 8D can be manufactured.
[0169]
In the photoelectric deposition method and the electrodeposition method, since a release layer is provided on the deposition substrate, it is not necessary to apply large heat or pressure when transferring the optical waveguide or the like to the substrate, and the substrate, the optical waveguide or the like is damaged. There is nothing.
The release layer preferably has a critical surface tension of 30 dyne / cm or less and does not affect the electrodeposition current. Specifically, a commercially available waterproof fluororesin spray can be used. Silicone resin or silicone oil can also be used. Furthermore, a thin film of unsaturated fatty acid such as oleic acid is also suitable.
[0170]
In the photo-deposition method and the electrodeposition method, the refractive index of the clad layer and the core layer is adjusted by using different refractive indexes as the film forming material, and fine particles for adjusting the refractive index are added to the electrodeposition solution. Or by combining them.
[0171]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.
[0172]
Example 1
In this example, when the clad layer is formed, light irradiation is not performed, and a voltage exceeding the Schottky barrier of the optical semiconductor is applied, so that an optical waveguide having a structure as shown in FIG. Show the process.
[0173]
(1) Preparation of electrodeposition solution for core formation
As an electrodepositable polymer material, a styrene-acrylic acid copolymer (hereinafter referred to as “electrodeposition”) having a molecular weight of 11,000, a molar ratio of styrene monomer to all monomers used for polymerization of 36%, an acid value of 120, and a deuterium substitution rate of 33%. (Referred to as a functional polymer material D1). The electrodepositable polymer material D1 was polymerized using a monomer of a styrene monomer in which a hydrogen atom bonded to a benzene ring portion was replaced with a deuterium atom.
Next, 7.0 g of electrodepositable polymer material D1 and 0.1 g of titanium oxide having a diameter of 10 nm are dispersed and mixed in 100 g of pure water, and dimethylaminoethanol (water-soluble, at a rate of 180 mmol / l, A liquid having a boiling point of 110 ° C. or more and a vapor pressure of 100 mHg or less), and further adjusted to pH 7.8 and conductivity of 15 mS / cm using tetramethylammonium hydroxide and ammonium chloride, and this is electrodeposition for core formation A liquid was used.
[0174]
(2) Preparation of electrodeposition solution for clad formation
As an electrodepositable polymer material, a styrene-acrylic acid copolymer (hereinafter referred to as “electrodeposition” having a molecular weight of 11,000, a molar ratio of styrene monomer to all monomers used in the polymerization of 21%, an acid value of 120, and a deuterium substitution rate of 15%. The high molecular weight material D2 ") was used. The electrodepositable polymer material D2 was polymerized using a monomer of a styrene monomer in which a hydrogen atom bonded to a benzene ring portion was replaced with a deuterium atom.
Next, as in the above (1), 7.0 g of the electrodepositable polymer material D2 is dispersed and mixed in 100 g of pure water, dimethylaminoethanol is further added at a rate of 180 mmol / l, and tetramethylammonium hydro hydride is further added. Using oxide and ammonium chloride, the pH was adjusted to 7.8 and the conductivity was adjusted to 15 mS / cm, and this was used as an electrodeposition solution for clad formation.
[0175]
(3) Fabrication of optical waveguide fabrication substrate
A transparent conductive film made of ITO (indium tin oxide) with a film thickness of 150 nm was formed on one surface of a 0.5 mm-thick alkali-free glass substrate (Corning Corp., 7059 glass), and further on its surface, TiO with a film thickness of 200 nm₂A film was formed by an RF sputtering method.
[0176]
(4) Fabrication of optical waveguide
In the general tripolar arrangement shown in FIG. 4, the electrodeposition solution for forming the clad is used as the electrodeposition solution, and TiO is applied to the saturated calomel electrode.₂When a film was used as a working electrode and a bias voltage applied to the working electrode was applied at 2.3 V for 20 seconds, TiO 2 was applied.₂A lower cladding layer having a thickness of 5 μm was formed on the entire surface of the film formation surface.
Next, the electrodeposition solution was replaced with a core forming electrodeposition solution without drying the clad layer, and a proximity exposure apparatus manufactured by Yamashita Denso as shown in FIG. 2 (light intensity at wavelength of 365 nm: 50 mW / cm²) And a core photomask, and when the bias voltage applied to the working electrode is 1.8 V, irradiation with ultraviolet rays through the electrodeposition liquid from the upper side of the substrate for 70 seconds gives TiO 2₂A core layer having a thickness of 21 μm and a width of 20 μm was formed only in the region irradiated with light on the film formation surface.
Next, without drying the clad layer and the core layer, the electrodeposition liquid was replaced with an electrodeposition liquid for clad formation, and a bias voltage applied to the working electrode was applied at 6 V for 40 seconds.₂An upper cladding layer having a thickness of 20 μm was formed on the entire surface of the film formation surface. Thus, the board | substrate with which the core layer and the clad layer were formed was taken out from the liquid tank, and it dried with clean air after washing | cleaning with a pure water, and completed the optical waveguide board | substrate, and obtained the optical waveguide of Example 1.
[0177]
The manufactured optical waveguide was cut to a length of 40 mm with a dicing saw and the insertion loss was measured. As a result, it was found that the transmission loss was about 0.91 dB / cm at a wavelength of 0.85 μm.
[0178]
(Example 2)
(1) Preparation of electrodeposition solution for core formation
As an electrodepositable polymer material, a styrene-acrylic acid copolymer (hereinafter referred to as “electrodeposition” having a molecular weight of 6000, a molar ratio of styrene monomer to all monomers used in the polymerization of 38%, an acid value of 113, and a deuterium substitution rate of 42%. Polymeric material D3 ") was used. The electrodepositable polymer material D3 was polymerized using monomers of a styrene monomer and an acrylic acid monomer in which hydrogen atoms were replaced with deuterium atoms.
Next, 7.0 g of electrodepositable polymer material D3 and 0.5 g of titanium oxide having a diameter of 10 nm are dispersed and mixed in 100 g of pure water, and dimethylaminoethanol (water-soluble, at a rate of 180 mmol / l, Liquid with a boiling point of 110 ° C. or higher and a vapor pressure of 100 mHg or less), and further adjusted to pH 7.8 and conductivity 35 mS / cm using tetramethylammonium hydroxide and ammonium chloride, and this is electrodeposition for core formation A liquid was used.
[0179]
(2) Preparation of electrodeposition solution for clad formation
As in the above (1), 7.0 g of the electrodepositable polymer material D3 is dispersed and mixed in 100 g of pure water, dimethylaminoethanol is further added at a rate of 180 mmol / l, and tetramethylammonium hydroxide and ammonium chloride are further added. Was used to adjust the pH to 7.8 and the conductivity to 45 mS / cm, and this was used as an electrodeposition solution for forming a clad.
(3) Fabrication of optical waveguide fabrication substrate
As the optical waveguide fabrication substrate, the same substrate as in Example 1 was fabricated.
[0180]
(4) Fabrication of optical waveguide
In a general tripolar arrangement as shown in FIG. 1, an electrodeposition solution for clad formation is used as an electrodeposition solution, and TiO is applied to a saturated calomel electrode.₂Using the electrode as a working electrode, the bias voltage applied to the working electrode is set to 1.8 V, and ultraviolet rays are irradiated from the back side of the substrate. The ultraviolet ray is a projection type exposure apparatus manufactured by Ushio Electric Co., Ltd. (light intensity of wavelength 365 nm, 50 mW / cm²)It was used. The projection type exposure apparatus was adjusted so as to form an image once on the lower clad photomask and further on the titanium oxide surface, which is the back surface of the substrate, via an optical lens. When this apparatus was exposed for 35 seconds, TiO₂A lower cladding layer having a thickness of 15 μm and a width of 25 μm was formed only in the region irradiated with light on the film formation surface (see FIG. 6B).
[0181]
Next, without drying the clad layer, the electrodeposition solution is replaced with the electrodeposition solution for core formation, the photomask is changed to that for the core, and the bias voltage applied to the working electrode is set to 2.8 V. When irradiated with UV light from the back side for 5 seconds, TiO₂A core layer having a thickness of 5 μm and a width of 18 μm was formed only in the region irradiated with light on the film formation surface (see FIG. 6C).
Next, without drying the clad layer and the core layer, the electrodeposition liquid is replaced with the electrodeposition liquid for clad formation, and the bias voltage applied to the working electrode is changed to 1. When UV is applied for 25 seconds from the back side of the substrate at 8V, TiO₂A side cladding layer having a thickness of 5 μm was formed only in the region irradiated with light on the film formation surface (see FIG. 6D).
[0182]
Next, without drying the clad layer and the core layer, the electrodeposition liquid is replaced with an electrodeposition liquid for clad formation, the photomask is replaced with that for the upper clad, and the bias voltage applied to the working electrode is 1.8 V. When irradiating UV light from the back side of the substrate for 40 seconds, TiO₂An upper cladding layer having a thickness of 17 μm was formed only in the region irradiated with light on the film formation surface (see FIG. 6E).
Thus, the board | substrate with which the core layer and the clad layer were formed was taken out from the liquid tank, and it dried with clean air after wash | cleaning with a pure water, and completed the optical waveguide board | substrate, and obtained the optical waveguide of Example 2.
[0183]
When the produced optical waveguide was cut into a length of 30 mm by a dicing saw and the insertion loss was measured, it was found that the transmission loss was about 0.81 dB / cm at a wavelength of 0.85 μm.
The produced optical waveguide had good shape accuracy and the upper part was flat. It was possible to form optical functional parts such as an optical waveguide and a microlens array by performing a similar photo-deposition process in a portion where the cladding layer does not exist. Furthermore, since the upper portion of the optical waveguide becomes flat, it is easy to form an optical functional component on the upper portion of the optical waveguide by another process.
[0184]
(Example 3)
In this example, an example is shown in which an optical waveguide having a structure similar to that shown in FIG. 5D is formed by forming titanium oxide, which is an optical semiconductor thin film, by oxidation treatment of titanium.
[0185]
(1) Preparation of electrodeposition solution for clad formation
In 100 g of pure water, 5 g of electrodepositable polymer material D3 and 1 g of magnesium fluoride fine particles (refractive index: 1.38) having a diameter of 10 nm are dispersed and mixed, and dimethylaminoethanol is further added at a rate of 180 mmol / l. Sodium hydroxide and sodium chloride were used to adjust the pH to 7.8 and the conductivity to 32 mS / cm, and this was used as an electrodeposition solution for clad formation.
[0186]
(2) Preparation of electrodeposition liquid for core formation
Electrodepositable polymer material D1: 5 g was dispersed and mixed in 100 g of pure water, dimethylaminoethanol was added thereto at a rate of 180 mmol / l, pH 7.8, conductivity 52 mS using sodium hydroxide and sodium chloride. / Cm, and this was used as the electrodeposition solution for core formation.
[0187]
(3) Fabrication of optical waveguide fabrication substrate
The surface of the metal titanium plate having a thickness of 0.5 mm was oxidized by high heat treatment to form a titanium oxide layer having a thickness of 1000 nm on the surface, and this was used as an optical waveguide manufacturing substrate. Moreover, it insulated by coat | covering the part other than the titanium oxide layer of the metal titanium plate surface formed with the epoxy resin.
[0188]
(4) Fabrication of optical waveguide
In a general tripolar arrangement as shown in FIG. 4, the electrodeposition solution for forming the clad is used as the electrodeposition solution, and TiO is applied to the saturated calomel electrode.₂When the layer was used as a working electrode and a bias voltage applied to the working electrode was applied at 3 V for 40 seconds, a lower cladding layer having a thickness of 25 μm was formed on the entire surface of the TiO 2 layer.
Next, without drying the cladding layer, the electrodeposition solution was replaced with a core-forming electrodeposition solution, and a proximity exposure apparatus manufactured by Yamashita Denso as shown in FIG. 2 (light intensity of wavelength 365 nm, 90 mW / cm).²) And a core photomask, and when the bias voltage applied to the working electrode is 2.5 V, UV irradiation is performed for 21 seconds through the electrodeposition liquid from the upper side of the substrate.₂A core layer having a thickness of 12 μm was formed only in the region irradiated with light on the layer forming surface.
[0189]
Next, the electrodeposition liquid was replaced with the electrodeposition liquid for forming the clad without drying the clad layer and the core layer, and a bias voltage applied to the working electrode was applied for 3 seconds with a device as shown in FIG. TiO₂An upper cladding layer having a thickness of 20 μm was formed on the entire surface of the layer.
Thus, the board | substrate with which the core layer and the clad layer were formed was taken out from the liquid tank, and it dried with clean air after wash | cleaning with a pure water, and completed the optical waveguide board | substrate, and obtained the optical waveguide of Example 3.
When the obtained optical waveguide was cut into a length of 20 mm by a dicing saw and the insertion loss was measured, it was found that the transmission loss was about 0.94 dB / cm at a wavelength of 0.85 μm.
[0190]
Example 4
In this example, an example is shown in which an optical waveguide having a structure similar to that shown in FIG. 5D is formed by forming zinc oxide, which is an optical semiconductor thin film, by anodizing zinc.
[0191]
(1) Preparation of electrodeposition solution for clad formation
In 100 g of pure water, electrodepositable polymer material D1: 10 g and magnesium fluoride fine particles (refractive index: 1.38) 0.3 g having a diameter of 10 nm are dispersed and mixed, and dimethylaminoethanol is added thereto at a rate of 180 mmol / l. In addition, the pH was adjusted to 7.8 and the conductivity was 52 mS / cm using sodium hydroxide and sodium chloride, and this was used as an electrodeposition solution for forming a clad.
[0192]
(2) Preparation of electrodeposition liquid for core formation
In 100 g of pure water, 5 g of electrodepositable polymer material D3 and 0.25 g of titanium oxide fine particles (refractive index 2.3) having a diameter of 10 nm are dispersed and mixed, and dimethylaminoethanol is added thereto at a rate of 180 mmol / l. Further, using sodium hydroxide and sodium chloride, the pH was adjusted to 7.8 and the conductivity was adjusted to 32 mS / cm, and this was used as the electrodeposition liquid for core formation.
[0193]
(3) Fabrication of optical waveguide fabrication substrate
The surface of a 2 mm thick zinc plate was oxidized by anodizing to form a 1000 nm thick zinc oxide layer on the surface, which was used as an optical waveguide fabrication substrate. Moreover, it insulated by coat | covering a part other than the zinc oxide layer of the zinc plate surface formed with the epoxy resin.
[0194]
(4) Fabrication of optical waveguide
In the general tripolar arrangement shown in FIG. 4, a bias voltage applied to the working electrode is applied by using the electrodeposition solution for forming the clad as the electrolytic solution and the zinc oxide layer as the working electrode with respect to the saturated calomel electrode. When applied at 3 V for 30 seconds, a lower cladding layer having a thickness of 20 μm was formed on the entire surface of the zinc oxide.
Next, without drying the clad layer, the electrodeposition solution is replaced with the electrodeposition solution for core formation, and a He-Cd laser (light intensity of 331 nm, light intensity of 10 mW / cm) that can be scanned by a scanning stage as shown in FIG.²) And the He—Cd laser is scanned from the upper side of the substrate through the electrodeposition solution at a speed of 0.3 mm / s with the bias voltage applied to the working electrode being 1.8 V, the surface of the zinc oxide layer is irradiated with light. A core layer having a thickness of 15 μm was formed only in the formed region.
Next, without drying the clad layer and the core layer, the electrodeposition solution was replaced with an electrodeposition solution for clad formation, and a bias voltage applied to the working electrode was applied at 3 V for 90 seconds. An upper cladding layer having a thickness of 20 μm was formed on the entire surface.
Thus, the board | substrate with which the core layer and the clad layer were formed was taken out from the liquid tank, and it dried with clean air after wash | cleaning with a pure water, and completed the optical waveguide board | substrate, and obtained the optical waveguide of Example 4.
[0195]
When the obtained optical waveguide was cut into a length of 50 mm by a dicing saw and the insertion loss was measured, it was found that the transmission loss was about 0.92 dB / cm at a wavelength of 0.85 μm.
[0196]
(Example 5)
In this example, an example is shown in which an optical waveguide having a structure similar to that shown in FIG.
[0197]
(1) Fabrication of deposition substrate
A transparent conductive film made of ITO having a thickness of 220 nm is formed on one side of a 1 mm-thick alkali-free glass plate (manufactured by Corning) by a sputtering method, and TiO having a thickness of 300 nm is further formed on the surface.₂A film was formed by an RF sputtering method. Next, a release layer was formed by spin-coating a 1% oleic acid solution (ethyl acetate solvent) at 4000 rpm for 30 seconds on the surface on which the TiO2 film was formed.
[0198]
(2) Electrodeposition liquid for clad layer and core layer
The same composition as the electrodeposition liquid used in Example 4 was used.
(3) Formation of cladding layer and core layer
In the same manner as in Example 2, a lower clad layer-core layer-side clad layer-upper clad layer was formed on the release layer (see FIGS. 7B to 7E), and the substrate was taken out of the liquid tank. Then, after washing with pure water and drying with clean air, an optical waveguide was produced.
[0199]
(4) Transfer of optical waveguide
A polyester film having a thickness of 0.5 mm heated to 150 ° C. is placed on the surface of the optical waveguide, and is heated and pressed between two rolls in a linear pressure state of 400 g / cm at a linear velocity of 10 mm / sec. After that, peeling was performed between the release layer and the optical waveguide, and the produced optical waveguide was transferred onto a polyester film to obtain an optical waveguide of Example 5 in which the optical waveguide was formed on the polyester film surface.
When a 50 mm linear portion of the obtained optical waveguide was cut out and the insertion loss was measured, it was found that the transmission loss was about 0.96 dB / cm at a wavelength of 0.85 μm.
[0200]
(Example 6)
(1) Preparation of electrodeposition solution for core formation
As an electrodepositable polymer material, the molecular weight is 18000, the molar ratio (%) of styrene monomer, acrylic acid monomer, and butyl acrylate monomer used for polymerization is 35:15:50, acid value 120, deuterium substitution rate A 52% styrene-acrylic acid-butyl acrylate copolymer (hereinafter referred to as “electrodepositing polymer material D4”) was used. The electrodepositable polymer material D4 was polymerized using a monomer of a styrene monomer in which a hydrogen atom bonded to a benzene ring portion was replaced with a deuterium atom.
[0201]
Next, 7.0 g of electrodepositable polymer material D4 and 0.5 g of titanium oxide having a diameter of 10 nm are dispersed and mixed in 100 g of pure water, and dimethylaminoethanol (water-soluble, at a rate of 180 mmol / l, A liquid having a boiling point of 110 ° C. or more and a vapor pressure of 100 mHg or less), and further adjusted to pH 7.8 and conductivity 55 mS / cm using tetramethylammonium hydroxide and ammonium chloride, and this is electrodeposition for core formation Liquid.
(2) Preparation of electrodeposition solution for clad formation
As in (1) above, 7.0 g of the electrodepositable polymer material D4 is dispersed and mixed in 100 g of pure water, and dimethylaminoethanol is further added at a rate of 180 mmol / l, and tetramethylammonium hydroxide and ammonium chloride are further added. Was used to adjust the pH to 7.8 and the conductivity to 75 mS / cm, and this was used as an electrodeposition solution for clad formation.
(3) Fabrication of optical waveguide fabrication substrate
As the optical waveguide fabrication substrate, the same substrate as in Example 1 was fabricated.
[0202]
(4) Fabrication of optical waveguide
In a general tripolar arrangement as shown in FIG. 1, an electrodeposition solution for clad formation is used as an electrodeposition solution, and TiO is applied to a saturated calomel electrode.₂Using the electrode as a working electrode, the bias voltage applied to the working electrode is set to 1.8 V, and ultraviolet rays are irradiated from the back side of the substrate. The ultraviolet ray is a projection type exposure apparatus manufactured by Ushio Electric Co., Ltd. (light intensity of wavelength 365 nm, 80 mW / cm²)It was used. The projection type exposure apparatus was adjusted so as to form an image once on the lower clad photomask and further on the titanium oxide surface, which is the back surface of the substrate, via an optical lens. When this device was exposed for 25 seconds, TiO₂A lower cladding layer having a thickness of 10 μm and a width of 25 μm was formed only in the region irradiated with light on the film formation surface (see FIG. 6B).
[0203]
Next, without drying the clad layer, the electrodeposition solution is replaced with the electrodeposition solution for core formation, the photomask is changed to that for the core, and the bias voltage applied to the working electrode is set to 1.8 V. When irradiated with UV from the back side for 75 seconds, TiO₂A core layer having a thickness of 21 μm and a width of 45 μm was formed only in the region irradiated with light on the film formation surface (see FIG. 6C).
Next, without drying the clad layer and the core layer, the electrodeposition liquid is replaced with the electrodeposition liquid for clad formation, and the bias voltage applied to the working electrode is changed to 1. When UV is applied for 25 seconds from the back side of the substrate at 8V, TiO₂A side cladding layer having a thickness of 55 μm was formed only in the region irradiated with light on the film formation surface (see FIG. 6D).
[0204]
Next, without drying the clad layer and the core layer, the electrodeposition liquid is replaced with an electrodeposition liquid for clad formation, the photomask is replaced with that for the upper clad, and the bias voltage applied to the working electrode is 2.8 V. When irradiating UV light from the back side of the substrate for 40 seconds, TiO₂An upper cladding layer having a thickness of 15 μm was formed only in the region irradiated with light on the film formation surface (see FIG. 6E).
Thus, the board | substrate with which the core layer and the clad layer were formed was taken out from the liquid tank, and it dried with clean air after wash | cleaning with a pure water, and completed the optical waveguide board | substrate, and obtained the optical waveguide of Example 2.
[0205]
When the produced optical waveguide was cut into a length of 50 mm by a dicing saw and the insertion loss was measured, it was found that the transmission loss was about 0.95 dB / cm at a wavelength of 0.85 μm.
[0206]
(Example 7)
In this example, when the clad layer is formed, light irradiation is not performed, and a voltage exceeding the Schottky barrier of the optical semiconductor is applied, so that an optical waveguide having a structure as shown in FIG. Show the process.
[0207]
(1) Preparation of electrodeposition solution for core formation
As an electrodepositable polymer material, a styrene-acrylic acid copolymer having a molecular weight of 11,000, a molar ratio of styrene monomer to all monomers used for polymerization of 36%, an acid value of 120, a glass transition point of 75 ° C., and a deuterium substitution rate of 33% (Electrodepositable polymer material D1) was used. The electrodepositable polymer material D1 was polymerized using a monomer of a styrene monomer in which a hydrogen atom bonded to a benzene ring portion was replaced with a deuterium atom.
Next, 7.0 g of electrodepositable polymer material D1 and 0.1 g of titanium oxide having a diameter of 10 nm are dispersed and mixed in 100 g of pure water, and dimethylaminoethanol (water-soluble, at a rate of 180 mmol / l, A liquid having a boiling point of 110 ° C. or more and a vapor pressure of 100 mHg or less), and further adjusted to pH 7.8 and conductivity of 15 mS / cm using tetramethylammonium hydroxide and ammonium chloride, and this is electrodeposition for core formation A liquid was used.
[0208]
(2) Preparation of electrodeposition solution for clad formation
As an electrodepositable polymer material, a styrene-acrylic acid copolymer having a molecular weight of 11,000, a molar ratio of styrene monomer to all monomers used in the polymerization of 21%, an acid value of 120, and a deuterium substitution rate of 15% (electrodepositable polymer) Material D2) was used. The electrodepositable polymer material D2 was polymerized using a monomer of a styrene monomer in which a hydrogen atom bonded to a benzene ring portion was replaced with a deuterium atom.
Next, as in the above (1), 7.0 g of the electrodepositable polymer material D2 is dispersed and mixed in 100 g of pure water, dimethylaminoethanol is further added at a rate of 180 mmol / l, and tetramethylammonium hydro hydride is further added. Using oxide and ammonium chloride, the pH was adjusted to 7.8 and the conductivity was adjusted to 15 mS / cm, and this was used as an electrodeposition solution for clad formation.
[0209]
(3) Fabrication of optical waveguide fabrication substrate
A transparent conductive film made of ITO (indium tin oxide) with a film thickness of 150 nm was formed on one surface of a 0.5 mm-thick alkali-free glass substrate (Corning Corp., 7059 glass), and further on its surface, TiO with a film thickness of 200 nm₂A film was formed by an RF sputtering method.
[0210]
(4) Fabrication of optical waveguide
In the general tripolar arrangement shown in FIG. 4, the electrodeposition solution for forming the clad is used as the electrodeposition solution, and TiO is applied to the saturated calomel electrode.₂When a film was used as a working electrode and a bias voltage applied to the working electrode was applied at 2.3 V for 20 seconds, TiO 2 was applied.₂A lower cladding layer having a thickness of 5 μm was formed on the entire surface of the film formation surface.
Next, the electrodeposition solution was replaced with a core forming electrodeposition solution without drying the clad layer, and a proximity exposure apparatus manufactured by Yamashita Denso as shown in FIG. 2 (light intensity at wavelength of 365 nm: 50 mW / cm²) And a core photomask, and when the bias voltage applied to the working electrode is 1.8 V, irradiation with ultraviolet rays through the electrodeposition liquid from the upper side of the substrate for 70 seconds gives TiO 2₂A core layer having a thickness of 21 μm and a width of 20 μm was formed only in the region irradiated with light on the film formation surface.
Next, without drying the clad layer and the core layer, the electrodeposition liquid was replaced with an electrodeposition liquid for clad formation, and a bias voltage applied to the working electrode was applied at 6 V for 40 seconds.₂An upper cladding layer having a thickness of 20 μm was formed on the entire surface of the film formation surface. The substrate on which the core layer and the clad layer are formed in this manner is taken out from the liquid tank, washed with pure water, and then dried in a clean oven maintained at 72 ° C. for 30 minutes to complete the optical waveguide substrate. The optical waveguide of Example 7 was obtained.
[0211]
When the manufactured optical waveguide was cut into a length of 40 mm by a dicing saw and the insertion loss was measured, it was found that the transmission loss was about 0.78 dB / cm at a wavelength of 0.85 μm.
[0212]
(Example 8)
(1) Preparation of electrodeposition solution for core formation
As an electrodepositable polymer material, a styrene-acrylic acid copolymer having a molecular weight of 6000, a molar ratio of styrene monomer to all monomers used in the polymerization of 38%, an acid value of 113, a glass transition point of 97 ° C., and a deuterium substitution rate of 42% (Electrodepositable polymer material D3) was used. The electrodepositable polymer material D3 was polymerized using monomers of a styrene monomer and an acrylic acid monomer in which hydrogen atoms were replaced with deuterium atoms.
Next, 7.0 g of electrodepositable polymer material D3 and 0.5 g of titanium oxide having a diameter of 10 nm are dispersed and mixed in 100 g of pure water, and dimethylaminoethanol (water-soluble, at a rate of 180 mmol / l, Liquid with a boiling point of 110 ° C. or higher and a vapor pressure of 100 mHg or less), and further adjusted to pH 7.8 and conductivity 35 mS / cm using tetramethylammonium hydroxide and ammonium chloride, and this is electrodeposition for core formation A liquid was used.
[0213]
(2) Preparation of electrodeposition solution for clad formation
As in the above (1), 7.0 g of the electrodepositable polymer material D3 is dispersed and mixed in 100 g of pure water, dimethylaminoethanol is further added at a rate of 180 mmol / l, and tetramethylammonium hydroxide and ammonium chloride are further added. Was used to adjust the pH to 7.8 and the conductivity to 45 mS / cm, and this was used as an electrodeposition solution for forming a clad.
(3) Fabrication of optical waveguide fabrication substrate
As the optical waveguide fabrication substrate, the same substrate as in Example 1 was fabricated.
[0214]
(4) Fabrication of optical waveguide
In a general tripolar arrangement as shown in FIG. 1, an electrodeposition solution for clad formation is used as an electrodeposition solution, and TiO is applied to a saturated calomel electrode.₂Using the electrode as a working electrode, the bias voltage applied to the working electrode is set to 1.8 V, and ultraviolet rays are irradiated from the back side of the substrate. The ultraviolet ray is a projection type exposure apparatus manufactured by Ushio Electric Co., Ltd. (light intensity of wavelength 365 nm, 50 mW / cm²)It was used. The projection type exposure apparatus was adjusted so as to form an image once on the lower clad photomask and further on the titanium oxide surface, which is the back surface of the substrate, via an optical lens. When this apparatus was exposed for 35 seconds, TiO₂A lower cladding layer having a thickness of 15 μm and a width of 25 μm was formed only in the region irradiated with light on the film formation surface (see FIG. 6B).
[0215]
Next, without drying the clad layer, the electrodeposition solution is replaced with the electrodeposition solution for core formation, the photomask is changed to that for the core, and the bias voltage applied to the working electrode is set to 2.8 V. When irradiated with UV light from the back side for 5 seconds, TiO₂A core layer having a thickness of 5 μm and a width of 18 μm was formed only in the region irradiated with light on the film formation surface (see FIG. 6C).
Next, without drying the clad layer and the core layer, the electrodeposition liquid is replaced with the electrodeposition liquid for clad formation, and the bias voltage applied to the working electrode is changed to 1. When UV is applied for 25 seconds from the back side of the substrate at 8V, TiO₂A side cladding layer having a thickness of 5 μm was formed only in the region irradiated with light on the film formation surface (see FIG. 6D).
[0216]
Next, without drying the clad layer and the core layer, the electrodeposition liquid is replaced with an electrodeposition liquid for clad formation, the photomask is replaced with that for the upper clad, and the bias voltage applied to the working electrode is 1.8 V. When irradiating UV light from the back side of the substrate for 40 seconds, TiO₂An upper cladding layer having a thickness of 17 μm was formed only in the region irradiated with light on the film formation surface (see FIG. 6E).
The substrate on which the core layer and the clad layer are formed in this manner is taken out from the liquid tank, washed with pure water, and then dried in a clean oven maintained at 99 ° C. for 1 hour to complete the optical waveguide substrate. The optical waveguide of Example 8 was obtained.
[0217]
When the produced optical waveguide was cut into a length of 30 mm by a dicing saw and the insertion loss was measured, it was found that the transmission loss was about 0.71 dB / cm at a wavelength of 0.85 μm.
[0218]
(Comparative Example 1)
As the electrodepositable polymer material, instead of the deuterium-substituted electrodepositable polymer material D1 used in Example 1, this electrodepositable polymer material D1 was not deuterium substituted at all. A molecular material (hereinafter referred to as “electrodepositing polymer material D01”) was used. In the polymerization of the electrodepositable polymer material D01, the same monomer as that used for the polymerization of the electrodepositable polymer material D1 was used, but a monomer that was not deuterium substituted was used.
An optical waveguide of Comparative Example 1 was prepared and evaluated in the same manner as in Example 1 except that the electrodepositable polymer material used was different. As a result, it was found that the transmission loss was about 1.42 dB / cm at a wavelength of 0.85 μm.
[0219]
(Comparative Example 2)
As the electrodepositable polymer material, instead of the deuterium-substituted electrodepositable polymer material D3 used in Example 2, the electrodepositable polymer material D3 was not deuterated at all. A molecular material (hereinafter referred to as “electrodepositable polymer material D03”) was used. In the polymerization of the electrodepositable polymer material D03, the same monomer as that used in the polymerization of the electrodepositable polymer material D3 was used, but a monomer not deuterated was used.
An optical waveguide of Comparative Example 2 was produced and evaluated in the same manner as Example 2 except that the electrodepositable polymer material used was different. As a result, it was found that the transmission loss was about 1.41 dB / cm at a wavelength of 0.85 μm.
[0220]
【The invention's effect】
  As described above, according to the present invention, it is possible to easily form a fine pattern and to reduce the loss of harmful waste liquid, and to use an electrodeposition method or a photo-deposition method, so that an optical waveguide having a small transmission loss and a high accuracy can be obtained.The roadSimple and can be manufactured with high productivityManufacturing method of optical waveguideCan be provided.
  Furthermore, the fine pattern can be formed with higher accuracy.Manufacturing method of optical waveguideCan be provided.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing an example of an electrodeposition apparatus using a projection exposure apparatus used when manufacturing an optical waveguide.
FIG. 2 is a conceptual diagram showing an example of an electrodeposition apparatus using a proximity exposure apparatus used when manufacturing an optical waveguide.
FIG. 3 is a conceptual diagram showing an example of an electrodeposition apparatus using a scanning laser exposure apparatus, which is used when manufacturing an optical waveguide.
FIG. 4 is a conceptual diagram showing an example of an electrodeposition apparatus used when an optical waveguide is produced by an electrodeposition method.
FIG. 5 is a diagram illustrating an example of an optical waveguide and its formation process.
FIG. 6 is a diagram showing another example of the optical waveguide and its formation process.
FIG. 7 is a diagram showing another example of the optical waveguide and its formation process.
FIG. 8 is a diagram showing another example of the optical waveguide and its formation process.
[Explanation of symbols]
10 Insulating substrate
12 Conductive thin film
13 Release layer
14, 32 Optical semiconductor thin film
16, 17, 20 Clad layer
18 Core layer
30, 32, 34 Optical waveguide substrate
71 photomask
72, 73 Imaging optical lens
75 Hg-Xe uniform irradiation light source
78 Scanning laser writing device
80 Electrodeposition tank
90 Means for applying a voltage, such as a potentiostat
91 Counter electrode
92 Reference electrode such as saturated calomel electrode

Claims (11)

A method of manufacturing an optical waveguide that transmits information using light in a wavelength range of at least 700 nm to 1350 nm,
  The electrodeposition material includes at least an electrodeposition polymer material, 10% to 90% of hydrogen atoms constituting the electrodeposition polymer material are substituted with deuterium atoms, and the electrodeposition material is formed from the electrodeposition material. The first cladding layer, the core layer, and the second cladding without drying by electrodeposition formation using an electrodeposition liquid having a transmission loss of 1 dB / cm or less with respect to light in the wavelength range of 700 nm to 1350 nm. A method of manufacturing an optical waveguide, comprising laminating layers. The electrodepositable polymer material is at least one hydrophobic monomer selected from alkenes, dienes, styrene, and derivatives thereof, and acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, crotonic acid, and cinnamon. 2. The method for producing an optical waveguide according to claim 1, comprising a copolymer obtained by polymerizing one kind of hydrophilic monomer selected from acid, phthalic acid, and derivatives thereof. The electrodepositable polymer material is at least one hydrophobic monomer selected from alkenes, dienes, styrene, and derivatives thereof, and acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, crotonic acid, and cinnamon. acid, phthalic acid, and a one hydrophilic monomer selected from derivatives thereof, methacrylic acid esters, acrylic acid esters, one plastic monomer chosen maleic esters anhydrides, and derivatives thereof 2. The method for producing an optical waveguide according to claim 1, further comprising : The electrodepositable polymer material contains a copolymer polymerized by using at least one kind of monomer in which at least a part of hydrogen atoms constituting the monomer is substituted with deuterium atoms. The manufacturing method of the optical waveguide of Claim 1 . Forming the first clad layer, the core layer and the second clad layer on the release layer using the electrodeposition liquid, and then transferring the first clad layer, the core layer and the second clad layer to the substrate; The method of manufacturing an optical waveguide according to claim 1, wherein The method of manufacturing an optical waveguide according to claim 1, wherein the light is laser light having a wavelength of 850 nm. The method for producing an optical waveguide according to claim 1, wherein 20% to 60% of hydrogen atoms constituting the electrodepositable polymer material are substituted with deuterium atoms. The method for manufacturing an optical waveguide according to claim 1, wherein the electrodeposition liquid contains fine particles for refractive index adjustment. The electrodepositable polymer material is a copolymer polymerized from at least a styrene monomer and an acrylic acid monomer, and at least a part of hydrogen atoms of the styrene monomer and / or the acrylic acid monomer before polymerization is deuterium. 2. The method of manufacturing an optical waveguide according to claim 1, wherein the light is a laser beam having a wavelength of 850 nm, which is substituted with an atom. From the aqueous electrodeposition liquid containing the electrodepositable polymer material as an electrodeposition material, the electrodepositable polymer material is deposited to form the first cladding layer, the core layer, and the second cladding layer in a wet state. 2. The optical waveguide according to claim 1, comprising at least an electrodeposition film deposition / formation step, and a drying step of drying the heat-treated first clad layer, core layer, and second clad layer in the wet state. A manufacturing method of
The method for producing an optical waveguide, wherein a temperature of the heat treatment is within a range of ± 15 ° C. of a glass transition point (Tg) of the electrodepositable polymer material . From the aqueous electrodeposition liquid containing the electrodepositable polymer material as an electrodeposition material, the electrodepositable polymer material is deposited to form the first cladding layer, the core layer, and the second cladding layer in a wet state. 2. The optical waveguide according to claim 1, comprising at least an electrodeposition film deposition / formation step, and a drying step of drying the heat-treated first clad layer, core layer, and second clad layer in the wet state. A manufacturing method of
  The method of manufacturing an optical waveguide, wherein the temperature of the heat treatment is in a range of 60 to 200 ° C.

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