JP3559528B2 - Opto-electric circuit board - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an opto-electric circuit board used for an optical communication module or the like, and more particularly, to an opto-electric circuit board having an optical waveguide formed on an electric circuit board.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, optical communication modules and the like have been used in which various optical devices are mounted on an opto-electric circuit board in which, for example, an electric circuit using a wiring conductor and an optical circuit using an optical waveguide are formed on a silicon substrate. . In addition, there has been proposed an opto-electric circuit board in which an optical waveguide is formed on a ceramic circuit board which has better electrical high-frequency characteristics and mechanical strength than a silicon substrate, and can realize a high electric wiring density by multilayering.
[0003]
On the other hand, as the optical waveguide, for example, a silica-based optical waveguide in which a three-dimensional clad portion and a core portion are formed using a silica film formed by a flame deposition method on a quartz glass substrate or a silicon substrate, or lithium niobate is used. There is an optical waveguide or the like in which a single crystal substrate is used as a cladding portion and titanium is thermally diffused on the substrate to form a core portion in a three-dimensional waveguide shape.
[0004]
However, since formation of these silica-based optical waveguides and the like requires heat treatment at a high temperature of about 1000 ° C. or more, an electric circuit board serving as a base when forming an optical circuit using these optical waveguides on the electric circuit board is required. Will damage it.
[0005]
On the other hand, instead of these conventional silica-based optical waveguides and the like which require high-temperature processing during fabrication, optical waveguides made of organic optical materials that can be formed at low temperatures are being studied. As the organic optical material used for the optical waveguide, PMMA (polymethyl methacrylate), polycarbonate, polyimide, polysiloxane, BCB (benzocyclobutene), fluororesin, and the like have been studied.
[0006]
As a method of manufacturing an optical waveguide made of these organic optical materials, a lower cladding layer is formed on a silicon substrate or a glass substrate, and then a core layer having a higher refractive index than the lower cladding layer is formed. The core layer is formed by processing the core layer by RIE (reactive ion etching) or the like using thin film microfabrication technology, and then the upper cladding layer having a lower refractive index than the core is covered to form a three-dimensional light guide. A method of forming a wave path has been performed.
[0007]
[Problems to be solved by the invention]
However, when an optical waveguide made of an organic optical material is to be formed on an electric circuit board such as a ceramic circuit board, an organic optical material for the optical waveguide and a wiring conductor made of metal or the like which is an electric wiring of the electric circuit board are required. The lower cladding layer made of the organic optical material for the optical waveguide is peeled off from the wiring conductor of the electric circuit board in the post-process such as the manufacturing process of the optical waveguide and the subsequent device mounting due to the low adhesion strength of the lower cladding layer. There is a problem that cracks occur in the above.
[0008]
As a means for solving such a problem, the present inventor has disclosed in Japanese Patent Application No. 2000-43128 an intermediate layer made of silicon oxide or silicon between a wiring conductor and an electric circuit board having a wiring conductor formed on an upper surface thereof. A photoelectric circuit board is proposed in which an organic optical waveguide is formed using a layer made of an organic optical material having a hydroxyl group or an alkyl group as a lower cladding layer, with an intervening layer. According to this, the hydroxyl group at the end of the surface of the intermediate layer and the hydroxyl group and the alkyl group of the lower cladding layer are bonded by dehydration polymerization or dealcoholization polymerization, so that the adhesion strength between them can be improved.
[0009]
Although the optical waveguide in the opto-electric circuit board proposed in Japanese Patent Application No. 2000-43128 has improved adhesion strength to the board, the surface of the wiring conductor is made of a noble metal such as gold or platinum. In the case where the width has a large area exceeding 100 μm, peeling may occur when the optical waveguide layer is subjected to a process such as a via hole forming process after forming the optical waveguide, which exerts an excessive load on the optical waveguide layer. There was a point to be further improved.
[0010]
The present invention has been devised in view of the above-mentioned problems of the prior art, and an object thereof is to provide an opto-electric circuit board in which an organic optical waveguide is formed with sufficient adhesion strength on a wiring conductor of the electric circuit board. Is to do.
[0011]
[Means for Solving the Problems]
The opto-electric circuit board of the present invention is a metal circuit comprising at least one of titanium, chromium, niobium, tungsten, molybdenum, and tantalum on an electric circuit board on which a wiring conductor made of a noble metal is formed on the upper surface. Forming an optical waveguide with a layer composed of an organic optical material having a hydroxyl group or an alkyl group as the lower cladding layer with a layer interposed Then, the hydroxyl group on the surface of the metal layer and the hydroxyl group or the alkyl group on the lower cladding layer are bonded by dehydration polymerization or dealcoholization polymerization. It is characterized by having done.
[0012]
In addition, the opto-electric circuit board of the present invention has a structure in which at least one of titanium, chromium, niobium, tungsten, molybdenum and tantalum is formed between the wiring conductor and the electric circuit board on which a wiring conductor made of a noble metal is formed on the upper surface. An optical waveguide in which a layer made of an organic optical material having a hydroxyl group or an alkyl group is formed as a lower cladding layer with a metal layer made of silicon and an intermediate layer made of silicon oxide or silicon formed on the metal layer interposed therebetween Then, a hydroxyl group on the surface of the intermediate layer and a hydroxyl group or an alkyl group on the lower cladding layer are bonded by dehydration polymerization or dealcoholization polymerization. It is characterized by having done.
[0013]
Further, the optoelectronic circuit board according to the present invention is characterized in that, in each of the above-described configurations, the organic optical material is a siloxane-based polymer.
[0014]
According to the opto-electric circuit board of the present invention, a metal layer made of at least one of titanium, chromium, niobium, tungsten, molybdenum, and tantalum is interposed on a wiring conductor made of a noble metal such as gold or platinum of the electric circuit board. Then, a layer made of an organic optical material having a hydroxyl group or an alkyl group is used as a lower cladding layer. Light Form waveguide Then, the hydroxyl groups on the surface of the metal layer and the hydroxyl groups or alkyl groups on the lower cladding layer are bonded by dehydration polymerization or dealcoholization polymerization. As a result, the noble metal such as gold or platinum of the wiring conductor and the metal layer made of at least one of titanium, chromium, niobium, tungsten, molybdenum and tantalum are firmly joined by metal bonding, and the lower cladding layer is formed of the metal layer. Since the hydroxyl group at the surface end and the hydroxyl group or alkyl group of the lower cladding layer of the optical waveguide are strongly bonded by dehydration polymerization or dealcoholization polymerization, the organic optical waveguide can be formed on the wiring conductor made of noble metal with sufficient adhesion strength. The formed opto-electric circuit board can be obtained.
[0015]
Also, a metal layer made of at least one of titanium, chromium, niobium, tungsten, molybdenum and tantalum, and an intermediate layer made of silicon oxide or silicon formed on this metal layer, on a wiring conductor made of a noble metal of the electric circuit board To form an optical waveguide with a layer made of an organic optical material having a hydroxyl group or an alkyl group as the lower cladding layer Then, the hydroxyl groups on the surface of the intermediate layer and the hydroxyl groups or alkyl groups on the lower cladding layer are bonded by dehydration polymerization or dealcoholization polymerization In this case, the noble metal of the wiring conductor and the metal layer made of at least one of titanium, chromium, niobium, tungsten, molybdenum, and tantalum are firmly joined by metal bonding, and silicon oxide or silicon formed on the metal layer Is formed by a known method such as a sputtering method, an electron beam evaporation method, an ion beam evaporation method, a laser ablation film forming method, or a CVD method, so that the intermediate layer is formed on the surface of the metal layer in a highly active state. Since a chemical bond is formed by the formation of the layer and a physical anchor effect is obtained by driving the film-forming material particles into the wiring conductor surface, a greater adhesion strength to the wiring conductor surface is obtained. As well as being obtained, the hydroxyl groups at the surface termination of the intermediate layer and the hydroxyl groups and alkyl groups in the lower cladding layer of the optical waveguide are dehydrated. Since the strongly bonded by coupling or dealcoholization polymerization, it is possible to obtain an optical electric circuit substrate formed with the organic optical waveguide at a greater bonding strength even on the wiring conductor made of precious metal.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the photoelectric circuit board of the present invention will be described with reference to the drawings.
[0017]
FIG. 1 shows the light of the present invention. Electric circuit board It is sectional drawing which shows an example of embodiment. In FIG. 1, reference numeral 1 denotes a substrate, and 2 denotes a wiring conductor formed on the upper surface of the substrate 1, and these constitute an electric circuit substrate. Reference numeral 3 denotes a metal layer, 4 denotes a lower cladding layer made of an organic optical material for an optical waveguide, 5 denotes a core portion of the optical waveguide, and 6 denotes an upper cladding layer of the optical waveguide.
[0018]
The substrate 1 forms an electric circuit and an optical circuit light Various substrates used to handle optical signals such as optical integrated circuit substrates and opto-electronic mixed substrates, such as silicon substrates, alumina substrates, glass ceramic substrates, and multilayer ceramic electric circuits. A ceramic electric circuit board or a plastic electric wiring board on which a substrate / thin film multilayer electric circuit is formed can be used.
[0019]
The wiring conductor 2 forms an electric circuit board by forming a predetermined electric circuit on the surface or inside of the substrate 1, and at least the outermost surface is made of a noble metal such as gold (Au) or platinum (Pt). is there. The wiring conductor 2 can be formed in a desired wiring pattern by using a metal thin film forming technique such as a sputtering method, an electron beam evaporation method, an ion beam evaporation method, a laser ablation film forming method, a CVD method, or a thin film processing technique such as photolithography. It is sufficient to process it. Also, a desired wiring pattern may be formed by utilizing a well-known metallizing technique for a ceramic substrate by screen printing or the like.
[0020]
The metal layer 3 is a layer formed on at least the surface of the wiring conductor 2 on the upper surface of the substrate 1 and made of at least one of titanium, chromium, niobium, tungsten, molybdenum, and tantalum. As a method for forming the metal layer 3, a sputtering method, an electron beam evaporation method, an ion beam evaporation method, a laser ablation film formation method, a CVD method, or the like can be used. Among them, the sputtering method and the ion beam evaporation method are preferable because the adhesion effect between the metal layer 3 and the wiring conductor 2 is increased by the anchor effect because the effect of implanting the film-forming material particles on the surface of the wiring conductor 2 is large. .
[0021]
In the present invention, the metal or alloy composed of at least one of titanium, chromium, niobium, tungsten, molybdenum, and tantalum is used as the metal layer 3 because the wiring conductor 2 and the metal layer 3 and the metal layer 3 and the metal layer 3 are formed thereon. This is because the adhesion strength with the lower cladding layer 4 can be sufficiently increased. The reason is that the metal layer 3 and the wiring conductor 2 can be firmly joined by metal bonding, the surface of the metal layer 3 can be terminated with a hydroxyl group, and that the lower cladding layer 4 made of an organic optical material has Since an alkyl group is contained, a hydroxyl group on the surface of the metal layer 3 and a hydroxyl group or an alkyl group of the lower cladding layer 4 are firmly bonded to each other by dehydration polymerization or dealcoholization polymerization, and a large adhesion strength is obtained between the two layers. That's why.
[0022]
The thickness of the metal layer 3 is preferably 10 nm or more in order to obtain sufficient coverage with the metal layer 3. On the other hand, when the metal layer 3 is formed by a sputtering method, an electron beam evaporation method, an ion beam evaporation method, a laser ablation film formation method, a CVD method, or the like, the film stress is usually 100 MPa or more, and the When the thickness is large, there is a problem that the substrate 1 is largely warped due to a film stress, a layer is peeled off from the surface of the substrate 1, or a crack is generated. On the other hand, if the thickness of the metal layer 3 is 500 nm or less, the film stress can be suppressed to the same level as that of the lower cladding layer 4 made of an organic optical material, and such a problem does not occur.
[0023]
Although not shown, the adhesion strength can be further increased by forming an intermediate layer made of silicon oxide or silicon on the metal layer 3. As a method of forming the intermediate layer, a sputtering method, an electron beam evaporation method, an ion beam evaporation method, a laser ablation film formation method, a CVD method, or the like may be used. In this case, a chemical bond due to the formation of the layer on the surface of the metal layer 3 in a highly active state and a physical anchor effect by driving the film-forming material particles into the surface of the wiring conductor 2 are obtained. A large adhesion strength is obtained, and the surface of the intermediate layer can be terminated with hydroxyl groups, and the lower cladding layer 4 made of an organic optical material contains hydroxyl groups and alkyl groups. This is because the hydroxyl group and the alkyl group of the lower cladding layer 4 are firmly bonded to each other by dehydration polymerization or dealcoholization polymerization, and a large adhesion strength is obtained between the two layers.
[0024]
The optical waveguide formed on the upper surface of the substrate 1 including the surface of the wiring conductor 2 with at least the metal layer 3 interposed between the upper surface and the wiring conductor 2 is formed in a cladding portion 4.6 composed of a lower cladding layer 4 and an upper cladding layer 6. The optical waveguide has a three-dimensional waveguide shape in which a core portion 5 is formed. As the forming material, an optical waveguide made of, for example, an organic optical material made of polyimide, fluorinated polyimide, siloxane-based polymer, PMMA, olefin-based resin or the like and having a hydroxyl group and an alkyl group as terminal groups is used.
[0025]
As a method for manufacturing the optical waveguide, first, the lower clad layer 4 is formed. An organic solvent solution of an organic optical material such as polyimide, fluorinated polyimide, siloxane-based polymer, PMMA, or olefin-based resin is applied to the substrate 1 on which the metal layer 3 is formed to a predetermined thickness by spin coating or the like. , By heat treatment.
[0026]
The core portion 5 is formed by applying an organic solvent solution of an organic optical material such as polyimide, fluorinated polyimide, siloxane-based polymer, PMMA, or olefin-based resin to the substrate 1 on which the lower cladding layer 4 is formed by a predetermined thickness, for example, by spin coating. After forming a layer by applying a heat treatment and heat-treating, it may be formed in a predetermined shape on the lower cladding layer 4 by using a known thin film microfabrication technique such as photolithography or RIE. Here, the core portion 5 is made of a material having a higher refractive index than the lower cladding layer 4.
[0027]
The upper cladding layer 6 is formed by forming an organic solvent solution of an organic optical material such as polyimide, fluorinated polyimide, siloxane-based polymer, PMMA, or olefin-based resin after the core portion 5 is formed. The substrate 1 is formed by applying a predetermined thickness to the substrate 1 by, for example, a spin coating method or the like and performing a heat treatment.
[0028]
Here, the height, width and refractive index of the core portion 5, the thickness and refractive index of the lower cladding layer 4, and the thickness and refractive index of the upper cladding layer 6 are designed to desired specifications using a known optical waveguide theory. do it.
[0029]
As described above, a buried optical waveguide having a three-dimensional waveguide shape is manufactured.
[0030]
When a siloxane-based polymer is used as the organic optical material for forming the lower clad layer 4 in the photoelectric circuit substrate of the present invention, for example, an organic solvent of the siloxane-based polymer is applied to the substrate 1 by spin coating or the like. The lower cladding layer 4 can be formed by low-temperature heat treatment at about 100 ° C. to 300 ° C., and a metal-containing siloxane-based polymer can be easily produced by mixing a metal alkoxide to control the refractive index. Since the refractive index can be controlled to a desired refractive index with high accuracy, the fabrication of the optical waveguide becomes easy. Further, since the shrinkage during the formation of the layer is small, the surface of the layer formed on the surface of the substrate 1 is excellent in flatness and smoothness, and the substrate 1 or the wiring conductor 2 having a large surface roughness as the substrate 1 Even when an undulating electric circuit board is used, an optical waveguide can be manufactured thereon with high accuracy.
[0031]
Further, since the siloxane-based polymer has a siloxane bond, an optical waveguide having excellent thermal stability can be formed. Further, it is easy to make a hydroxyl group or an alkyl group a terminal group, and when a film serving as the lower cladding layer 4 is formed on the metal layer 3, dehydration polymerization or dealcoholization polymerization with the hydroxyl group on the surface of the metal layer 3 is performed. Thereby, a large adhesion strength with the metal layer 3 is obtained.
[0032]
The siloxane-based polymer used for the cladding portions 4 and 6 and the core portion 5 of such an optical waveguide may be basically a resin containing a siloxane bond in the skeleton of the polymer. For example, polyphenylsilsesquioxane -Polydiphenylsilsesquioxane, polymethylphenylsilsesquioxane, etc. can be used.
[0033]
【Example】
Next, a specific example of the photoelectric circuit substrate of the present invention will be described.
[0034]
<Example 1>
First, a wide-area wiring conductor 2 having a three-layer structure of Ti / Pt / Au (thickness: 1000 nm / 500 nm / 5000 nm) and serving as a power supply wiring made of Au is formed on a substrate 1 made of silicon. Formed over the entire surface. Thereafter, a metal layer 3 made of titanium having a thickness of 5 nm was formed on the entire surface of the substrate 1 by using an electron beam evaporation method. Next, after performing hydrophilization treatment with an aqueous hydrogen peroxide solution, a step index type optical waveguide was formed in which the cladding portions 4.6 were composed of a siloxane-based polymer and the core portion 5 was composed of a titanium-containing siloxane-based polymer. At this time, the refractive index of the core portion 5 and the cladding portions 4 and 6 are 1.444 and 1.440, respectively, the width of the core portion 5 is 8 μm, the height is 8 μm, and the upper cladding layer 6 above the core portion 5 is formed. The thickness was 4 μm. The thickness of the lower cladding layer 4 between the substrate 1 and the core 5 was 12 μm.
[0035]
At this time, no peeling or cracking of the optical waveguide layer was observed during fabrication. Also, in the chip separation by dicing after the formation of the optical waveguide, peeling of the optical waveguide layer was not observed. Furthermore, no problem was found in the waveguide characteristics of the optical waveguide.
[0036]
<Example 2>
First, a wide-area wiring conductor 2 having a three-layer structure of Ti / Pt / Au (thickness: 1000 nm / 500 nm / 5000 nm) and serving as a power supply wiring made of Au is formed on a substrate 1 made of silicon. Formed over the entire surface. Thereafter, a metal layer 3 made of titanium having a thickness of 5 nm was formed on the entire surface of the substrate 1 by using an electron beam evaporation method. Next, an intermediate layer made of a silicon oxide layer having a thickness of 10 nm was formed on the entire surface of the substrate 1 by a sputtering method. Next, a step index type optical waveguide was formed in which the cladding portions 4 and 6 were made of a siloxane polymer and the core portion 5 was made of a titanium-containing siloxane polymer. At this time, the refractive index of the core portion 5 and the cladding portion are 1.444 and 1.440, respectively, the width of the core portion 5 is 8 μm, the height is 8 μm, and the thickness of the upper cladding layer 6 located above the core portion 5. The length was 4 μm. The thickness of the lower cladding layer 4 between the substrate 1 and the core 5 was 12 μm.
[0037]
At this time, no peeling or cracking of the optical waveguide layer was observed during fabrication. Also, in the chip separation by dicing after the formation of the optical waveguide, peeling of the optical waveguide layer was not observed. Furthermore, no problem was found in the waveguide characteristics of the optical waveguide.
[0038]
<Example 3>
First, a wiring conductor 2 having a three-layer structure of Ti / Pt / Au (thickness: 1000 nm / 500 nm / 5000 nm) made of Au on a substrate 1 made of silicon and patterned into a predetermined circuit wiring is formed. Formed. Thereafter, a photoresist pattern exposing the wiring conductor 2 is formed, a metal layer made of titanium having a thickness of 5 nm is formed on the entire surface of the substrate 1 by using an electron beam evaporation method, and the photoresist is removed by a lift-off method. A metal layer 3 made of titanium was formed on the surface of the wiring conductor 2. Next, after performing hydrophilization treatment with an aqueous hydrogen peroxide solution, a step index type optical waveguide was formed in which the cladding portions 4.6 were composed of a siloxane-based polymer and the core portion 5 was composed of a titanium-containing siloxane-based polymer. At this time, the refractive index of the core portion 5 and the cladding portions 4 and 6 are 1.444 and 1.440, respectively, the width of the core portion 5 is 8 μm, the height is 8 μm, and the upper cladding layer located above the core portion 5. 6 had a thickness of 4 μm. The thickness of the lower cladding layer 4 between the substrate 1 and the core 5 was 12 μm.
[0039]
At this time, no peeling or cracking of the optical waveguide layer was observed during fabrication. Also, in the chip separation by dicing after the formation of the optical waveguide, peeling of the optical waveguide layer was not observed. Furthermore, no problem was found in the waveguide characteristics of the optical waveguide.
[0040]
<Example 4>
First, a wiring conductor 2 having a three-layer structure of Ti / Pt / Au (thickness: 1000 nm / 500 nm / 5000 nm) made of Au on a substrate 1 made of silicon and patterned into a predetermined circuit wiring is formed. Formed. Thereafter, a photoresist pattern exposing the wiring conductor 2 is formed, a metal layer made of titanium having a thickness of 5 nm is formed on the entire surface of the substrate 1 by using an electron beam evaporation method, and the photoresist is removed by a lift-off method. A metal layer 3 made of titanium was formed on the surface of the wiring conductor 2. Next, an intermediate layer made of a silicon oxide layer having a thickness of 10 nm was formed on the entire surface of the substrate 1 by a sputtering method. Next, a step index type optical waveguide in which the cladding portions 4 and 6 were composed of a siloxane-based polymer and the core portion 5 was composed of a titanium-containing siloxane-based polymer was formed. At this time, the refractive index of the core portion 5 and the cladding portions 4 and 6 are 1.444 and 1.440, respectively, the width of the core portion 5 is 8 μm, the height is 8 μm, and the upper cladding layer located above the core portion 5. 6 had a thickness of 4 μm. The thickness of the lower cladding layer 4 between the substrate 1 and the core 5 was 12 μm.
[0041]
At this time, no peeling or cracking of the optical waveguide layer was observed during fabrication. Also, in the chip separation by dicing after the formation of the optical waveguide, peeling of the optical waveguide layer was not observed. Furthermore, no problem was found in the waveguide characteristics of the optical waveguide.
[0042]
<Example 5>
For comparison with the present invention, an example was formed on a silicon substrate having a three-layer structure of Ti / Pt / Au (thickness: 1000 nm / 500 nm / 5000 nm) and a wiring conductor 2 having a top surface made of Au formed on the entire surface. As in the case of 1, an attempt was made to form a step index optical waveguide in which the cladding portions 4 and 6 were made of a siloxane-based polymer and the core portion 5 was made of a titanium-containing siloxane-based polymer. In the case of this embodiment in which the metal layer 3 was not formed, the optical waveguide layer was completely peeled off from the substrate 1 in the step of forming the core portion 5.
[0043]
<Example 6>
Further, for comparison with the present invention, a cladding part 4.6 is formed of a siloxane-based polymer and a core part is formed on a silicon substrate having a three-layer structure of Ti / Pt / Au on which a wiring conductor 2 whose outermost surface is made of Au is formed. 5 formed a step index optical waveguide made of a titanium-containing siloxane-based polymer. At this time, as in Example 1, the refractive indices of the core portion 5 and the cladding portions 4 and 6 are 1.444 and 1.440, respectively, the width of the core portion 5 is 8 μm, the height is 8 μm, and the core portion 5 The thickness of the upper cladding layer 6 located on the top of the substrate was 4 μm. The thickness of the lower cladding layer 4 between the substrate 1 and the core 5 was 12 μm.
[0044]
In the case of the present embodiment in which the intermediate layer is not formed, the optical waveguide layer is in close contact with the surface of the silicon substrate 1 with sufficient strength in the portion where the wiring conductor 2 is not provided, so that the entire surface is peeled off as in the case of the fifth embodiment. However, peeling and cracking of the optical waveguide layer were observed in the portion of the wiring conductor 2.
[0045]
As described above, according to the present invention, it was confirmed that an opto-electric circuit board having an organic optical waveguide formed with sufficient adhesion strength on the wiring conductor of the electric circuit board could be provided.
[0046]
It should be noted that the present invention is not limited to the above-described embodiments, and various changes and improvements may be made without departing from the spirit of the present invention. For example, when the metal layer 3 is formed on the surface of Au of the wiring conductor 2, a diffusion suppressing layer such as Pt is interposed between Au and the metal layer 3 in order to suppress the diffusion of Au and the metal layer 3. You may let it.
[0047]
【The invention's effect】
As described above, according to the opto-electric circuit board of the present invention, at least one of titanium, chromium, niobium, tungsten, molybdenum, and tantalum is formed between the wiring conductor and the noble metal on the electric circuit board. A layer composed of an organic optical material having a hydroxyl group or an alkyl group with a metal layer interposed is used as the lower cladding layer. Light Form waveguide Then, the hydroxyl groups on the surface of the metal layer and the hydroxyl groups or alkyl groups on the lower cladding layer are bonded by dehydration polymerization or dealcoholization polymerization. As a result, the noble metal of the wiring conductor and the metal layer made of at least one of titanium, chromium, niobium, tungsten, molybdenum, and tantalum are firmly joined by metal bonding, and the lower cladding layer is bonded to the hydroxyl group at the surface termination of the metal layer. Since the hydroxyl group and alkyl group of the lower cladding layer of the optical waveguide are strongly bonded by dehydration polymerization or dealcoholization polymerization, an opto-electric circuit with an organic optical waveguide formed with sufficient adhesion strength on a noble metal wiring conductor A substrate was obtained.
[0048]
Further, according to the opto-electric circuit board of the present invention, a metal layer made of at least one of titanium, chromium, niobium, tungsten, molybdenum, and tantalum is provided between the wiring conductor made of the noble metal of the electric circuit board and the wiring conductor. An optical waveguide in which a layer made of an organic optical material having a hydroxyl group or an alkyl group is formed as a lower clad layer with an intermediate layer made of silicon oxide or silicon formed on the metal layer interposed therebetween. Then, the hydroxyl groups on the surface of the intermediate layer and the hydroxyl groups or alkyl groups on the lower cladding layer are bonded by dehydration polymerization or dealcoholization polymerization. Therefore, the noble metal of the wiring conductor and the metal layer made of at least one of titanium, chromium, niobium, tungsten, molybdenum, and tantalum are firmly joined by metal bonding, and silicon oxide or silicon formed on the metal layer is The intermediate layer is formed by a known method such as a sputtering method, an electron beam evaporation method, an ion beam evaporation method, a laser ablation film forming method, or a CVD method, so that the intermediate layer is formed on the surface of the metal layer in a highly active state. Is formed, chemical bonding is performed, and a physical anchor effect is obtained by driving the film-forming material particles into the wiring conductor surface, so that a greater adhesion strength to the wiring conductor surface is obtained. And the hydroxyl groups at the surface termination of the intermediate layer and the hydroxyl groups and alkyl groups in the lower cladding layer of the optical waveguide are dehydrated. Since the strongly bonded by multiplexer and de-alcohol polymer, it was possible to obtain an optical electric circuit substrate formed with the organic optical waveguide at a greater bonding strength even on the wiring conductor made of precious metal.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of a photoelectric circuit substrate of the present invention.
[Explanation of symbols]
1 ... substrate
2. Wiring conductor
3 ... Metal layer
4 ... Lower cladding layer (cladding part) of optical waveguide
5 ... Core part of optical waveguide
6 Upper cladding layer (cladding part) of optical waveguide

Claims (3)

On an electric circuit board on which a wiring conductor made of a noble metal is formed on an upper surface, a metal layer made of at least one of titanium, chromium, niobium, tungsten, molybdenum and tantalum is interposed between the wiring conductor and a hydroxyl group or an alkyl group. An optical waveguide having a layer made of an organic optical material having a group as a lower cladding layer was formed , and a hydroxyl group on the surface of the metal layer and a hydroxyl group or an alkyl group of the lower cladding layer were bonded by dehydration polymerization or dealcoholization polymerization . An opto-electric circuit board, characterized in that: A metal layer made of at least one of titanium, chromium, niobium, tungsten, molybdenum, and tantalum was formed between the wiring conductor and an electric circuit board on which a wiring conductor made of a noble metal was formed on the upper surface. An optical waveguide having a layer made of an organic optical material having a hydroxyl group or an alkyl group as a lower clad layer is formed by interposing an intermediate layer made of silicon oxide or silicon, and a hydroxyl group on the surface of the intermediate layer and the lower clad are formed. An optoelectronic circuit board, wherein a hydroxyl group or an alkyl group of a layer is bonded by dehydration polymerization or dealcoholization polymerization . 3. The opto-electric circuit board according to claim 1, wherein the organic optical material is a siloxane polymer.

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