JP2019167591A - Oxide film and method for manufacturing the same - Google Patents

Abstract

To provide an oxide film capable of forming a metal film having high adhesion, and a method for manufacturing the same.SOLUTION: The oxide film formed on at least a part of the surface of a base material includes essential titanium atoms and optional silicon atoms having 1:0-3:2 of a molar ratio of a titanium oxide to a silicon oxide and has a surface roughness Ra of 0.150 nm or more. The method for manufacturing the oxide film comprises: the coating film formation step of applying a coating agent for oxide film formation including an oxide or a precursor thereof having 1:0-3:2 of a molar ratio of titanium atoms to silicon atoms to the surface of the base material to form a coating film; and the coating film sintering step of sintering the coating film to obtain the oxide film. The surface roughness Ra of the oxide film is 0.150 nm or more.SELECTED DRAWING: None

Description

  The present invention relates to an oxide film and an oxide film manufacturing method, and more specifically, an oxide film is formed on the surface of a base material made of, for example, glass, ceramic, a silicon substrate, and the surface is metallized. The present invention relates to an oxide film for obtaining a metal plating structure and a manufacturing method thereof.

  A technique of plating a metal on a base material is used in the field of printed electronic circuits such as thin wire circuits using glass or ceramics as a base material, and is applied to electronic devices such as liquid crystal displays and semiconductor devices.

  As a technique for plating a metal on a base material, for example, a zinc oxide thin film is formed by applying a coating agent (coating solution) made from zinc acetate dihydrate on the surface of a non-conductive base material and then baking it. And forming a metal film thereon by plating to modify the surface of the non-conductive substrate and metallize it (Patent Document 1).

Japanese Patent Laid-Open No. 2006-533429

  However, in the technique described in Patent Document 1, even when a coating liquid is applied to the surface of a base material to form a zinc oxide thin film, swelling between the zinc oxide thin film and the metal film is likely to occur. The adhesion of the metal film was low.

  This invention is made | formed in view of such a situation, and it aims at providing the oxide film which can form a metal film with high adhesiveness, and its manufacturing method.

  In the oxide film formed on the base material, the inventors set the ratio of titanium atoms to silicon atoms within a predetermined range, and the surface roughness Ra within a predetermined range, whereby the oxide film is formed. The present inventors have found that it is possible to form a metal film having high adhesiveness, and have completed the present invention.

  (1) 1st invention of this invention is an oxide film formed in at least one part of the surface of a base material, Comprising: A titanium atom is contained essential, Inclusion of a silicon atom is arbitrary, Titanium oxide And silicon oxide in a molar ratio of 1: 0 to 3: 2 and an oxide film having a surface roughness Ra of 0.150 nm or more.

  (2) The second invention of the present invention is the oxide film according to claim 1, wherein, in the first invention, the thickness is 10 nm or more and 100 nm or less.

  (3) A third invention of the present invention is a method for producing an oxide film formed on at least a part of the surface of a substrate, comprising an oxide or a precursor thereof, and the oxide or a precursor thereof. Forming a coating film by applying a coating agent for forming an oxide film containing titanium atoms and silicon atoms in a molar ratio of 1: 0 to 3: 2 as a body to the surface of the substrate And a coating film baking step of baking the coating film to obtain the oxide film, and obtaining an oxide film having a surface roughness Ra of 0.150 nm or more. is there.

  (4) The fourth invention of the present invention is the method for producing an oxide film according to the third invention, wherein the baking temperature in the coating film baking step is 200 ° C. or higher and 600 ° C. or lower.

  ADVANTAGE OF THE INVENTION According to this invention, the oxide film which can form a metal film with high adhesiveness, and its manufacturing method can be provided.

  Embodiments of the present invention will be described below, but these are exemplarily shown, and it goes without saying that various modifications are possible without departing from the technical idea of the present invention.

≪About oxide film≫
The oxide film of the present invention is formed on at least a part of the surface of the substrate, contains a titanium atom essential, the silicon atom is optional, and titanium oxide and silicon oxide are in a molar state. It is contained at a ratio of 1: 0 to 3: 2 and the surface roughness Ra is 0.150 nm or more. By forming such a metal film, a metal film having high adhesion to the oxide film can be formed.

  Among these, regarding the composition of the oxide film, titanium oxide is essential, and titanium oxide and silicon oxide are included in a molar ratio of 1: 0 to 3: 2.

  Here, the ratio between the number of moles of titanium oxide and the number of moles of silicon oxide is 3: 2 or more than that (or the ratio of Si atoms / Ti atoms is 0.66). It is preferable that the ratio is 7: 3 or more than that (or the ratio of the number of Si atoms / the number of Ti atoms is 0.43 or less). As a result, when the oxide film forming coating agent is applied to the base material to form the oxide film, swelling between the base material and the oxide film is reduced. The adhesion can be further improved. Further, when electroless plating is performed on the oxide film, the metal film can be more easily formed.

  On the other hand, the ratio between the number of moles of titanium oxide and the number of moles of silicon oxide is set to 1: 0 or more than that (or the ratio of the number of Si atoms / the number of Ti atoms is larger than 0). It is preferable that the ratio of silicon oxide is 20: 1 or more (or the ratio of Si atom number / Ti atom number is 0.05 or more), more preferably 10: 1 or more. More preferably, the ratio of silicon atoms is higher (or the ratio of the number of Si atoms / Ti atoms is 0.10 or more), and the ratio of silicon oxide is 7: 1 or higher (or More preferably, the ratio of the number of Si atoms / Ti atoms is 0.14 or more. Thereby, since the adhesion amount of the catalyst formed in an oxide film can be increased more, the adhesiveness to the oxide film of a metal film can be improved further.

  The oxide film of the present invention may contain a compound other than titanium oxide and silicon oxide. Examples of metal atoms that can be contained in the oxide film other than titanium oxide and silicon oxide include copper oxide, zirconium oxide, aluminum oxide, and tin oxide. The content of these metal atoms is 1 mol% or less with respect to the total number of moles of oxides constituting the oxide film.

  On the other hand, when zinc oxide is formed on an oxide film by electroless plating or the like, zinc oxide elutes to make it difficult to form a metal film, and the electrical performance of the formed metal film. And damage the appearance. Therefore, the content of zinc atoms is preferably 10 mol% or less, more preferably 8 mol% or less, still more preferably 6 mol% or less, based on the total number of moles of oxides constituting the oxide film. Preferably it does not contain zinc oxide.

  Here, the surface roughness Ra of the oxide film is preferably 0.150 nm or more, more preferably 0.200 nm or more, and further preferably 0.300 nm or more. As a result, when a metal film is formed on the oxide film, the metal film easily becomes physically entangled with the porous structure of the oxide film, and more catalyst can be imparted to the surface of the oxide film. Therefore, desired high adhesion can be obtained between the oxide film and the metal layer.

  On the other hand, the upper limit of the surface roughness Ra of the oxide film is preferably less than 10.00 nm, more preferably less than 5.00 nm, and even more preferably less than 1.00 nm.

  The means for obtaining an oxide film having a surface roughness Ra within a desired range is not particularly limited. In addition to means for adjusting the temperature and time for forming a coating agent for forming an oxide film, oxide film formation Known means such as means for adjusting the molecular weight of the polycondensate of the oxide precursor contained in the coating agent can be used.

  The thickness of the oxide film is preferably 10 nm or more, more preferably 20 nm or more, and further preferably 30 nm or more. Thereby, since the amount of the catalyst provided to the oxide film increases, the adhesion with the metal film can be further enhanced.

  On the other hand, the upper limit of the thickness of the oxide film is preferably 100 nm or less, more preferably 60 nm or less, and even more preferably 50 nm or less. In particular, the occurrence of cracks in the oxide film can be reduced by setting the thickness of the oxide film to 60 nm or less.

  The oxide film of the present invention has a covalent bond generated by condensation of —OH groups and the like with the base material, and adhesion between the oxide film and the base material is enhanced by this covalent bond. Therefore, when a metal film is formed on the oxide film, the adhesion of the metal film to the substrate can be improved.

  More catalyst can be imparted to such an oxide film of the present invention. Thereby, the deposition of the metal film on the oxide film can be further promoted, and the adhesion of the metal film to the oxide film can be further enhanced.

≪Oxide film manufacturing method≫
The manufacturing method of the oxide film of the present invention includes a base material preparation step (S1) for preparing a base material, and a coating film formation in which the above-described coating agent for forming an oxide film is applied to the base material to form a coating film. A step (S2) and a coating film baking step (S3) for heating the coating film to form an oxide film are provided.

<(S1) Substrate preparation step>
In the base material preparation step (S1), a base material used for forming the oxide film is prepared, and pretreatment is performed as necessary.

[Substrate material]
As the base material used for forming the oxide film, a nonmetallic inorganic material that can withstand the temperature of the heat treatment described later can be used, and examples thereof include glass, ceramics, and silicon-based semiconductor materials. it can. In particular, when a metal film formed through an oxide film on a substrate is used as a wiring or the like in an electronic circuit, from the viewpoint of preventing conduction through the substrate, the substrate is non-conductive, for example, It is preferable to use one having an electrical resistivity of 10 ³ Ωm or more, more preferably 10 ⁶ Ωm or more.

  Among these, as glass, quartz glass, silica glass, borosilicate glass, aluminosilicate glass, aluminoborosilicate glass, soda lime glass (soda lime glass), float glass, fluoride glass, phosphate glass, borate glass, borosilicate In addition to amorphous glass such as acid glass and chalcogenide glass, glass ceramics in which a crystal phase is precipitated can be given.

Examples of ceramics include oxide ceramics containing alumina, beryllia, ceria, zirconia, and non-oxide ceramics such as carbides, borides, nitrides, and silicides. Specific examples of the ceramic material include alumina, aluminum nitride, β-TCP (β-type tricalcium phosphate), barium titanate (BaTiO ₃ ), and the like.

  Examples of the silicon-based semiconductor material include silicon wafers widely used in the semiconductor industry, which may have an oxidized surface on its surface and may contain a dopant inside.

  As a base material used for formation of an oxide film, it is not restricted to what consists of a single plate-shaped material, You may use the laminated body which laminated | stacked two or more plate-shaped base materials.

[Pretreatment of substrate]
It is preferable that the surface of the base material used for forming the oxide film has a smooth surface from the viewpoint of enhancing the adhesion of the metal film. More specifically, when glass or a silicon-based semiconductor material is used as the substrate, the average surface roughness Ra on the substrate surface is preferably 200 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less. It is. As the substrate, a material that is smaller than the average surface roughness Ra of the oxide film to be formed may be used, preferably less than 0.150 nm, and more preferably 0.100 nm or less. On the other hand, when ceramics are used as the substrate, the average surface roughness Ra on the substrate surface is preferably 1000 nm or less, more preferably 600 nm or less. Here, as a means for improving the smoothness on the surface of the substrate, for example, a known polishing means can be used.

  Moreover, it is preferable to wash | clean a base material before contact with the coating agent for oxide film formation. As a method for washing the substrate, a known method can be used. For example, a method of immersing the substrate in a solution containing a surfactant, a method of immersing the substrate in a polar organic solvent or a mixture thereof, alkaline And a method of immersing the substrate in the solution, and a combination of two or more of these methods.

<Coating film formation process (S2)>
In the coating film forming step (S2), a coating film is formed by applying a coating agent for forming an oxide film on a substrate.

[Coating agent for forming oxide film]
As the coating agent for forming an oxide film used in the coating film forming step, one containing at least one selected from an oxide and an oxide precursor and a solvent is used.

(Oxides, oxide precursors)
The oxide and oxide precursor contained in the coating agent for forming an oxide film essentially contain titanium atoms, the inclusion of silicon atoms is arbitrary, and the number of titanium atoms and the number of silicon atoms The ratio is a ratio of 1: 0 to 3: 2.

  Here, the ratio of the number of titanium atoms to the number of silicon atoms is 3: 2 or more than that (or the ratio of Si atoms / Ti atoms is 0.66). The ratio is preferably 7: 3 or more and more preferably (or the ratio of the number of Si atoms / the number of Ti atoms is 0.43 or less). As a result, when the oxide film forming coating agent is applied to the base material to form the oxide film, swelling between the base material and the oxide film is reduced. The adhesion can be further improved. Further, when electroless plating is performed on the oxide film, the metal film can be more easily formed.

  On the other hand, the ratio of the number of titanium atoms to the number of silicon atoms is 1: 0 or more than that (or the ratio of Si atom / Ti atom number is larger than 0). It is preferable that the ratio of silicon atoms is 20: 1 or more (or the ratio of the number of Si atoms / the number of Ti atoms is 0.05 or more), more preferably 10: 1 or more. More preferably, the ratio of silicon atoms is higher (or the ratio of the number of Si atoms / Ti atoms is 0.10 or more), and the ratio is higher than 7: 1 or more silicon atoms (or More preferably, the ratio of the number of Si atoms / the number of Ti atoms is 0.14 or more. Thereby, since the mechanical strength of the oxide film is increased, particularly when an oxide film having many voids is formed, it is possible to suppress a decrease in adhesion between the base material and the metal film due to the fracture of the oxide. Moreover, since the adhesion amount of the catalyst formed on the oxide film can be further increased, the adhesion of the metal film to the base material and the oxide film can be further enhanced.

  This coating agent for forming an oxide film can contain an oxide precursor in addition to the oxide. As the oxide precursor, a compound that functions as a source of the corresponding oxide can be used, and a compound that reacts to form an oxide while being applied to the base material and attached to the catalyst is applied. It can be contained in the agent. Such compounds include soluble salts of metals and silicon, and are roughly classified into organic soluble salts and inorganic soluble salts. Among these, as the organic soluble salt, for example, alkoxide such as methoxide, ethoxide, propoxide and butoxide, carboxylic acid compound such as acetate, diol compound, polyol compound, diketone complex, hydroxyketone complex, hydroxycarboxylic acid complex, etc. Complexes, hydrolysates thereof and the like can be mentioned. Examples of inorganic soluble salts include halides such as chlorides, bromides and iodides, and nitrates.

  In particular, by containing an oxide precursor such as a metal alkoxide in the coating agent for forming an oxide film, the oxide precursor can be easily dissolved or dispersed in the coating agent. It can be formed on the surface of the material and can be formed uniformly.

  The concentration of the oxide and the oxide precursor in the coating agent for forming an oxide film is preferably 10 mmol / l or more, more preferably in terms of the number of moles of metal atoms (including silicon atoms) contained in 1 liter of the coating agent. Is 50 mmol / l or more, more preferably 100 mmol / l or more. On the other hand, the upper limit of the concentration of the oxide and oxide precursor is preferably 1000 mmol / l or less, more preferably 800 mmol / l or less.

  Here, the concentration of titanium atoms in the coating agent for forming an oxide film is preferably 10 mmol / l or more, more preferably 50 mmol / l or more, and even more preferably, in terms of the number of moles of titanium atoms contained in 1 liter of coating agent. May be 80 mmol / l or more. On the other hand, the upper limit of the titanium atom concentration is preferably 1000 mmol / l or less, more preferably 800 mmol / l or less, and still more preferably 600 mmol / l or less.

  Further, the silicon atom content in the coating agent for forming an oxide film is arbitrary, but the silicon atom content is preferably more than 0 mmol / l in terms of the number of moles of silicon atoms contained in 1 liter of the coating agent. More preferably, it is 10 mmol / l or more, More preferably, it is good also as 30 mmol / l or more. On the other hand, the upper limit of the silicon atom concentration is preferably 200 mmol / l or less, more preferably 150 mmol / l or less, and still more preferably 100 mmol / l or less.

  As the oxide and the oxide precursor, a compound that leaves a metal atom other than titanium (Ti) and silicon (Si) in the oxide film may be contained. Examples of metal atoms that can be contained in oxides and oxide precursors other than titanium (Ti) and silicon (Si) include copper (Cu), zirconium (Zr), aluminum (Al), niobium (Nb), and cerium (Ce). ) And tin (Sn). The content of these metal atoms may be 50 mmol / l or less or 10 mmol / l or less in terms of the number of moles of metal atoms contained in 1 liter of the oxide film-forming coating agent. On the other hand, it is more preferable not to contain these metal atoms from the viewpoint of further improving the adhesion of the oxide film to the substrate.

  On the other hand, the zinc (Zn) atom lowers the stability of the coating agent, and when the metal film is formed on the oxide film by electroless plating or the like, the zinc oxide is eluted so that the metal film Is difficult to form, and the electrical performance and appearance of the formed metal film are impaired. Therefore, the content of zinc atoms in the oxide film-forming coating agent is preferably 100 mmol / l or less, more preferably 80 mmol / l in terms of the number of moles of zinc atoms contained in 1 liter of the oxide film-forming coating agent. 1 or less, more preferably 60 mmol / l or less, and most preferably no zinc atom.

(solvent)
As the solvent contained in the coating agent for forming an oxide film, a solvent capable of dissolving or dispersing an oxide or an oxide precursor can be used. Among these, it is preferable to use a solvent having sufficient paintability to the substrate. In addition, it is preferable to use a solvent that is in a liquid state within a temperature range of normal temperature (15 to 30 ° C.) because the coating agent can be prepared and stored at normal temperature.

  This solvent preferably has polarity in order to facilitate dissolution and dispersion of oxides and oxide precursors. More specifically, it is preferable to use water or a polar organic solvent as the solvent. Among these, the polar organic solvent includes alcohols such as ethanol, propanol, isopropanol, n-butanol, and glycol; methyl ethyl ketone, methyl isobutyl ketone, and isophorone. Ketones such as; esters and ethers such as methoxyethanol, 2-ethoxyethanol, 2-n-butoxyethanol, ethyl lactate, 2-ethoxyethyl acetate, and γ-butyrolactone; aromatic compounds such as toluene and xylene; and , N, N-dimethylacetamide, dimethylformamide, N-methylpyrrolidone and the like nitrogen-containing solvents. Moreover, the mixture of 2 or more types among these may be sufficient.

  Further, the solvent may be an aqueous solvent, and more specifically, a mixed solvent of a liquid and water excellent in compatibility with water. In particular, it may be a mixture of water and a polar organic solvent.

  Here, in a water-soluble coating agent for forming an oxide film using an aqueous solvent, as an oxide precursor to be contained in the coating agent for forming an oxide film, metal atoms (including silicon atoms), lactic acid, citric acid, It is preferable to contain a complex composed of a ligand such as EDTA, or a hydrolyzate or chloride of a metal or silicon salt. On the other hand, the coating agent for forming an oxide film using an organic solvent preferably contains a metal or silicon alkoxide, a diol compound, a complex, a polyol compound, a diketone complex, or a hydroxyketone complex as an oxide precursor.

(Surfactant)
The oxide film-forming coating agent may contain a surfactant (leveler) in order to improve the uniformity of the oxide film and improve the wettability to the substrate surface. In particular, in the case of a water-soluble coating agent for forming an oxide film, a surfactant may be necessary to reduce the surface tension and form a uniform oxide film. In the case of an oxide film-forming coating agent containing an oxide, a surfactant may be required to form a stable colloidal dispersion.

  Although it does not specifically limit as surfactant, For example, modified | denatured dimethylpolysiloxane (Shin-Etsu Chemical KP-341, KP-104), fluorocarbons, polyether (Sigma-Aldrich Triton X-100) Etc.

  The concentration of the surfactant in the coating agent for forming an oxide film is preferably in the range of 0.0001 to 5% by mass, more preferably in the range of 0.0005 to 3% by mass with respect to the total mass of the coating agent. It is.

(Acid and base)
In this coating agent for forming an oxide film, the porosity (porosity) and surface roughness Ra of the oxide film can be adjusted by proceeding with the polycondensation reaction of the oxide precursor and adjusting the molecular weight, In order to chelate and stabilize atoms, or to adjust the state of the surface charge of the oxide or oxide precursor, an acid or a base may be contained.

  Acids and bases that can be contained in the coating agent for forming an oxide film are not particularly limited, and inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid; acetic acid, lactic acid, 2-hydroxyisobutyl, methoxyethoxyacetic acid, γ-butyrolactone, and the like Organic acids and their condensates; bases such as sodium hydroxide, potassium hydroxide, ammonia and amines can be used.

  Among these, as the chelating agent, known compounds that chelate metal atoms contained in the oxide film can be used. For example, lactic acid, citric acid, 2-hydroxyisobutyric acid, methoxyethoxyacetic acid, 3,4- One or more of ethyl dihydroxybenzoate, triethanolamine, 3-hydroxy-2-butanone (acetoin), maltol, catechol, and 2,4-pentanedione can be preferably used. Among these, when 3-hydroxy-2-butanone is used as a chelating agent, the porosity of the oxide film can be maximized.

  The concentration of the chelating agent in the coating agent for forming an oxide film is preferably in the range of 0.1 to 20% by mass, more preferably in the range of 0.5 to 10% by mass with respect to the total mass of the coating agent. is there.

[Photosensitive material]
In addition, the coating agent for forming an oxide film may use a known photosensitive substance in order to enable formation of a pattern in the obtained oxide film.

[Formation of coating film]
In the coating film forming step, the above-described coating agent for forming an oxide film is applied to a substrate to form a coating film. The means for forming the coating film can be determined according to the composition of the coating agent for forming the oxide film, such as dip coating, spin coating, spray coating, curtain coating, rolling printing, screen printing, ink jet printing, and brush coating. The following means can be used. In particular, from the viewpoint of stably applying the colloid-forming coating agent to more substrates, it is preferable to use a dip coating, slit coating, roller coating or spin coating means.

  Although the temperature at the time of apply | coating a coating agent to a base material is set according to the coating method, the viscosity of a coating agent, etc., it is 5 degreeC or more, Preferably it is 10 degreeC or more, More preferably, you may be 20 degreeC or more. it can. On the other hand, the upper limit of the temperature at which the coating agent is applied to the substrate can be, for example, 90 ° C. or less, preferably 80 ° C. or less, and more preferably 60 ° C. or less.

  The coating film may be formed a plurality of times depending on the desired thickness of the oxide film. In particular, when the coating agent is applied to the substrate multiple times to form a coating film, the coating agent applied to the substrate is dried to remove the solvent, and then the coating agent is applied thereon. Is preferred. Thereby, since the dropping of the coating agent from the base material when the coating agent is applied in layers is reduced, an oxide film having a desired thickness can be easily formed. On the other hand, particularly when the coating agent is applied to the substrate by dip coating, the thickness of the coating film may be adjusted by adjusting the lifting speed of the substrate.

  The coating agent applied to the substrate can be dried as necessary to reduce dropping of the formed coating film. Here, the drying temperature of a coating agent is set according to the solvent used for a coating agent, for example, can be set to 30 degreeC or more, More preferably, to 50 degreeC or more. On the other hand, the upper limit of the drying temperature of the coating agent can be set to, for example, 350 ° C. or lower, more preferably 200 ° C. or lower.

<Coating film baking process (S3)>
In the coating film baking step (S3), the coating film applied to the substrate is heated, thereby forming an oxide film. As a result, the solvent contained in the coating film is removed, the oxide precursor is thermally decomposed to produce an oxide, and the oxide is sintered by condensation or the like, thereby being in close contact with the substrate. Stable oxide film can be obtained.

  In particular, when an oxide precursor is contained in the coating agent, after the coating agent is applied to the substrate, the precursor is thermally decomposed by heating in the presence of oxygen, thereby forming the base of the oxide film. It can be formed on a material. Further, when the coating agent contains a compound having an oxygen atom such as a metal alkoxide as the oxide precursor, its hydrolyzate or dehydrated polycondensate may be produced in the coating agent. Does not necessarily require oxygen during heating.

  The firing temperature (first firing temperature) in the coating film firing step is not particularly limited as long as a desired oxide film can be obtained, but is, for example, 200 ° C. or higher, more preferably 300 ° C. or higher, and further preferably 400 ° C. or higher. be able to.

  On the other hand, the upper limit of the first firing temperature is preferably 600 ° C. or lower, more preferably 550 ° C. or lower. In particular, when the first baking temperature is set to 600 ° C. or lower, recrystallization of the oxide film is difficult to occur, so that the applied amount of the catalyst can be further increased.

  The firing time (first firing time) in the coating film firing step is set according to the type of oxide or oxide precursor and the first firing temperature, but for example, 1 minute or more, more preferably 10 minutes or more, More preferably, it can be 30 minutes or more. On the other hand, the upper limit of the first firing time can be, for example, 180 minutes or less, more preferably 120 minutes or less, and even more preferably 90 minutes or less.

  In the coating film baking step, heating may be performed with a temperature gradient up to a predetermined first baking temperature. Here, when heating is performed by providing a temperature gradient, the temperature may be increased at a constant rate until the first baking temperature is reached, and at least in part, the temperature increasing rate is changed or the temperature is maintained. May be provided in part. In particular, when a time for holding the temperature during the temperature rise is provided, the temperature may be held at the above drying temperature from the viewpoint of suppressing damage to the coating film due to rapid evaporation of the solvent. And after providing a temperature gradient and heating, it is preferable to perform baking at a predetermined first baking temperature.

  In particular, the temperature gradient until the first firing temperature is reached is preferably 50 ° C./min or less, and more preferably 20 ° C./min or less. As a result, the oxide is first generated from the oxide precursor compound and then the sintering of the oxide proceeds because the temperature is slowly increased, thereby reducing the peeling of the oxide film from the substrate. Can do.

≪Manufacture of metal plating structure≫
The oxide film obtained by this invention can be preferably used for manufacture of a metal plating structure. Here, the manufacturing method of the metal plating structure using the oxide film includes, for example, a metal film forming step (S4) for forming a metal film on the oxide film, and a metal film baking step (S5) for baking the metal film. And having.

<Metal film forming step (S4)>
The metal film forming step (S4) is a plating for forming a metal film on the surface of the oxide film formed by the coating film forming step (S2) and the coating film baking step (S3) by electroless plating or electroplating. Process. Here, before the metal film forming step, there may be an acid-base treatment step of treating the oxide film with a treatment solution containing an acid or a base, or a catalyst provision step of imparting a catalyst to the oxide film.

[Acid-base treatment process]
The acid-base treatment step is an arbitrary step for treating the oxide film with a treatment liquid containing an acid or a base. By treating the oxide film with such a treatment liquid, the surface state of the substrate on which the oxide film is formed can be adjusted.

  Here, as the treatment liquid, a treatment liquid containing a base is preferably used, and an alkaline solution is more preferred. The alkaline solution only needs to have a pH value of pH = 10 or more. Specific examples thereof include hydroxide salts such as sodium hydroxide, potassium hydroxide and calcium hydroxide; Can be mentioned. By using a treatment liquid containing such a base, a negative charge is imparted to the surface of the oxide film. Therefore, when the catalyst application step described later is performed, the amount of adsorption of the catalyst can be increased.

  On the other hand, particularly when the content of titanium atoms in the oxide film is low, a treatment solution containing an acid, preferably an acidic aqueous solution having a pH value of pH = 1 to 5, may be used as the treatment solution. More specifically, for example, an organic acid such as sulfuric acid, hydrochloric acid, or acetic acid can be used as the treatment liquid.

  The treatment of the oxide film in the acid-base treatment step may be performed for 1 to 10 minutes at a temperature of 30 ° C. or more and 100 ° C. or less, for example, in a state where the treatment liquid is in contact with the oxide film.

[Catalyst application process]
A catalyst provision process is a process of providing a catalyst to at least one part of the surface of an oxide film. By applying a catalyst to the surface of the oxide film, the metal film is formed by using the catalyst as a nucleus in the metal film forming step (S3) described later, and therefore the deposition of the metal film on the oxide film is promoted. be able to. Moreover, the adhesion of the metal film to the oxide film can be enhanced by applying the catalyst.

  As the catalyst used in the catalyst application step, a catalyst metal or a compound thereof that promotes the formation of a metal film when plating is performed on the surface of the oxide film can be used in the form of an aqueous solution or an aqueous dispersion. As the catalyst metal, copper (Cu) or a metal element having a standard electrode potential on the positive side of copper (Cu) can be used. More specifically, palladium, copper, silver, gold, ruthenium, rhodium, Osmium, iridium and platinum can be used. Among these, it is more preferable to use palladium.

  As a specific example of the catalyst used in the catalyst application step, for example, described in Journal of The Electrochemical Society, 161 (14) D806-D812 (2014), an amino acid such as arginine or lysine is used as a ligand. Complexes can be used.

The amount of the catalyst applied to the surface of the oxide film is preferably 0.5 mg / m ² or more, more preferably 1.0 mg / m ² or more, and further preferably 2.0 mg / m ² or more in terms of metal. . Here, the amount of the catalyst in terms of “metal conversion” in the present specification is the mass of atoms of the catalyst metal contained in the catalyst. Thus, by increasing the amount of the catalyst applied to the oxide film, the deposition of the metal film on the oxide film can be further promoted, and the adhesion of the metal film to the oxide film is further enhanced. Can be increased. In particular, in the present invention, since the amount of the catalyst applied to the surface of the oxide film is increased, the adhesion of the metal film to the oxide film can be increased.

Here, when the catalyst is used in the form of an aqueous solution, after the catalyst is applied, the catalyst metal compound is reduced to the metal state by bringing the solution containing the reducing agent into contact with the catalyst on the substrate. Also good. Further, when the catalyst is used in the form of an aqueous dispersion, the catalyst is deposited on the oxide film, so that the reducing agent need not be brought into contact with the catalyst. Examples of the reducing agent for reducing the catalytic metal compound to a metal state include formaldehyde, hypophosphite, glyoxylic acid, DMAB (dimethylaminoborane), and NaBH ₄ .

  The reduction of the catalyst metal compound to the metal state may be performed for 1 to 10 minutes at a temperature of 30 ° C. or more and 100 ° C. or less, for example, in a state where the solution containing the reducing agent is in contact with the catalyst on the substrate.

[Plating process]
The plating process is a process of forming a metal film on the surface of the oxide film by performing an electroless plating process or an electroplating process. According to the present invention, when the oxide film is plated, it is possible to reduce the elution of the oxide film into the plating solution, thereby facilitating the formation of the metal film, and the long life of the plating solution. It can also bring about.

  Here, particularly when a non-conductive substrate or oxide film is used, an electroless plating process is performed on the surface of the oxide film to form a metal film, and then an electroplating process is performed using the metal film as an electrode. It is preferable that the metal film having a desired thickness is formed by performing the above in terms of shortening the time required for forming the metal film.

(Electroless plating treatment)
Among these, the electroless plating treatment is a method in which a metal film is deposited on the surface of an oxide film by bringing an oxide film provided with a catalyst into contact with a plating solution containing a chemical reducing agent as necessary. .

As the plating solution, a solution containing metal ions deposited as a metal film and a reducing agent can be used. Among these, as a metal ion, the solution containing Cu ion, Ni ion, Co ion, or Ag ion is mentioned, for example. Examples of the reducing agent include formaldehyde, hypophosphite, glyoxylic acid, DMAB (dimethylaminoborane) and NaBH ₄ .

  The plating solution may contain a pH adjuster, a complexing agent, an accelerator, and a stabilizer. Among these, stabilizers include, for example, mercaptobenzothiazole, thiourea, various other sulfur compounds, cyanide and / or ferrocyanide and / or cobalt cyanide, polyethylene glycol derivatives, heterocyclic nitrogen compounds, methyl Examples include butynol and propionitrile.

  The plating solution is prepared so that the metal film is formed at a predetermined deposition rate when it is brought into contact with the substrate on which the oxide film is formed. Here, the deposition rate of the metal film by the electroless plating treatment is preferably 10 nm / min or more, more preferably 15 nm / min or more. In particular, when the deposition rate is 10 nm / min or more, peeling of the metal film due to generation of hydrogen can be reduced.

  Further, the upper limit of the deposition rate of the metal film by the electroless plating treatment is preferably 25 nm / min or less, more preferably 20 nm / min or less from the viewpoint of productivity.

  The deposition of the metal film by the electroless plating treatment is preferably performed at a temperature of, for example, 20 ° C. or more and 80 ° C. or less until the metal film reaches a predetermined thickness. The thickness of the metal film formed by the electroless plating process is preferably set to 100 nm or more and 200 nm or less from the viewpoint of suppressing the generation of pinholes due to insufficient deposition and the trapping of gas generated by long-time deposition.

  The electroless plating treatment uses a plating solution that does not contain a chemical reducing agent and utilizes the difference between the oxidation-reduction potential of the deposited metal and the oxidation-reduction potential of the metal contained on the surface of the substrate. Alternatively, a method of depositing a metal film may be used.

(Drying of electroless plating film)
After the electroless plating process is performed on the surface of the oxide film to form a metal film, the metal film (electroless plated film) obtained by electroless plating may be dried. As a result, water molecules that have hydrated the surface of the metal film are discharged to the outside through the metal film, so that peeling of the metal film from the oxide film can be reduced.

  Here, the drying temperature of the electroless plating film can be, for example, 100 ° C. or higher, more preferably 120 ° C. or higher. On the other hand, the upper limit of the drying temperature can be, for example, 250 ° C. or lower, more preferably 200 ° C. or lower, and further preferably 150 ° C. or lower.

  The drying time of the electroless plating film is set according to the type and thickness of the metal film and the drying temperature, and can be set to, for example, 1 minute or more, more preferably 10 minutes or more. On the other hand, the upper limit of the drying time may be, for example, 120 minutes or less, more preferably 60 minutes or less.

(Electrolytic plating treatment)
In the electroplating process, an external current is applied to deposit a metal film on the surface of the substrate. By performing the electroplating process to form the metal film, a thick metal film can be efficiently formed.

  As the electrolytic plating treatment, a known method for depositing copper, nickel, silver, gold, tin, zinc, iron, lead or an alloy thereof as a metal film can be used. And as a plating solution for depositing copper, for example, a plating solution containing copper sulfate, sulfuric acid, sodium chloride and an organic sulfur compound can be used. Here, as the organic sulfur compound, it is preferable to use a compound having sulfur having a low oxidation number, for example, an organic sulfide or a disulfide.

<Metal film firing step (S5)>
The metal film firing step (S5) is a step of firing the metal film formed in the metal film formation step (S4).

  The firing temperature (second firing temperature) in the metal film firing step can be, for example, 250 ° C. or higher, more preferably 300 ° C. or higher. On the other hand, the upper limit of the second firing temperature may be, for example, 500 ° C. or less, more preferably 400 ° C. or less.

  The firing time (second firing time) in the metal film firing step is set according to the type of the base material, the types and thicknesses of the first metal film and the second metal film, and the second firing temperature. Min or more, more preferably 10 min or more. On the other hand, this second firing time can be, for example, 120 minutes or less, more preferably 60 minutes or less.

  In the metal film firing step, heating may be performed by providing a temperature gradient until a predetermined second firing temperature is reached. Here, when heating is performed by providing a temperature gradient, the temperature may be increased at a constant rate until the second baking temperature is reached, and at least in part, the rate of temperature increase is changed or the temperature is maintained. May be provided in part. And after providing a temperature gradient and heating, it is preferable to perform baking at a predetermined second baking temperature.

  In particular, the temperature gradient until the second firing temperature is reached is preferably 50 ° C./min or less, and more preferably 20 ° C./min or less. Thus, the internal stress generated in the oxide film or the metal film, such as distortion due to the difference in thermal expansion between the metal film and the base material, can be reduced by slowly increasing the temperature. In addition, since the solvent and the like contained in the metal film can be gradually evaporated, damage to the metal film due to firing can be reduced.

<Characteristics and applications of metal plating structure>
In the metal plating structure obtained in the present invention, the metal film formed on the surface has high peel strength with respect to the substrate. More specifically, the metal plating structure obtained in the present invention has a force required to peel the adhesive from the base material in the 90 ° direction after applying the adhesive to the metal film of the metal plating structure ( 90 ° peel adhesive strength) is preferably 0.3 kN / m or more, and more preferably 0.8 kN / m or more. Thereby, since peeling of the metal film from the oxide film is suppressed, the mechanical durability of the metal film in the metal plating structure can be enhanced.

  This metal plating structure can be widely used for applications in which metal is formed on a substrate made of an inorganic material such as glass, but in particular, when a non-conductive substrate or a semiconductor substrate is used as the substrate, It can be preferably used for printed electronic circuits, especially for interposers, flat panel displays, radio frequency identification (RFID) antennas, and the like, and highly reliable electronic circuits can be obtained in these applications.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention does not receive a restriction | limiting at all in these description.

≪Relationship between composition of coating agent for forming oxide film and surface roughness Ra of oxide film≫
Oxide film-forming coating agents (Nos. 1 to 9) were prepared by the following procedure, and an electroless process was performed using these oxide film-forming coating agents.

<Preparation of coating agent for forming oxide film (No. 1 to 9)>
Hereinafter, the detail of each component used for preparation of the coating agent for oxide film formation (No. 1-9) is shown below. The content of each component is as shown in Table 1.

  Among them, as the “Comp. 5221” of (A) oxide and oxide precursor, an alcohol solution of Si oligomer (product name: Comp. 5221, manufactured by JCU Corporation) was used.

  The coating materials for forming an oxide film (Nos. 1 to 9) were prepared by mixing the materials described in Table 1 so as to have the contents described in Table 1.

<Manufacture of oxide film using coating agent for forming oxide film>
(Base material preparation process)
As a base material, a glass plate of 50 × 50 × 0.7 (mm) made of aluminoborosilicate glass (product name: EN-A1, manufactured by Asahi Glass Co., Ltd.) was used. This glass plate was pretreated by immersing it in a 200 g / L NaOH aqueous solution at 50 ° C. for 10 minutes, washing with water, and air-drying.

(Coating film forming process)
A coating film was formed on the substrate using the above-described coating agent for forming an oxide film (No. 1 to 9). More specifically, the coating agent was applied to the substrate by dip coating, and then dried at 50 ° C. to form a coating film. Here, the pulling speed of the base material in dip coating was adjusted so that the thickness of the oxide to be formed was 40 nm.

(Coating film baking process)
Subsequently, the coating film baking process was performed with respect to the coating film formed in the base material, and the oxide film was obtained. Here, the baking of the coating film is performed by heating the inside of the furnace so as to increase the temperature at a temperature gradient of 10 ° C./min up to the first baking temperature of 550 ° C., and then for 60 minutes (the first baking temperature) Firing was performed for one firing time). Thereafter, the furnace was naturally cooled until the temperature in the furnace reached room temperature.

(Evaluation of oxide film)
About the obtained oxide film, surface roughness Ra was calculated | required. Here, the surface roughness Ra was measured using an atomic force microscope (product name: di Innova) manufactured by Veeco. As a result, for the oxide film forming coating agent (Nos. 1 to 7), the surface roughness Ra of the obtained oxide film is equal to the content of titanium oxide or silicon oxide in the oxide film forming coating agent. Regardless, it became almost the same level. Therefore, it is presumed that the surface roughness Ra of the oxide film is determined regardless of the content of titanium oxide or silicon oxide in the coating agent for forming an oxide film.

<< Examples 1-3, Comparative Examples 1-2 >>
<Manufacture of oxide film using coating agent for forming oxide film>
(Base material preparation process)
As a base material, a glass plate of 50 × 50 × 0.7 (mm) made of aluminoborosilicate glass (product name: EN-A1, manufactured by Asahi Glass Co., Ltd.) was used. This glass plate was pretreated by immersing it in a 200 g / L NaOH aqueous solution at 50 ° C. for 10 minutes, washing with water, and air-drying. At this time, the surface roughness Ra of the glass plate was less than 0.10 nm.

(Coating film forming process)
A coating film was formed on the substrate using the above-described coating agent for forming an oxide film (No. 5, 8, 9). More specifically, the coating agent was applied to the substrate by dip coating, and then dried at 50 ° C. to form a coating film. Here, the pulling speed of the base material in dip coating was adjusted so that the thickness of the oxide to be formed was 40 nm.

(Coating film baking process)
Subsequently, the coating film baking process was performed with respect to the coating film formed in the base material, and the oxide film was obtained. Here, the coating film is fired by heating the inside of the furnace so that the temperature rises at a temperature gradient of 10 ° C./min up to the firing temperature described in Table 2 (first firing temperature). Firing was performed for 60 minutes (first firing time) at the firing temperature. Thereafter, the furnace was naturally cooled until the temperature in the furnace reached room temperature.

<Electroless process to oxide film>
(Metal film forming process)
A metal film was formed on the surface of the obtained oxide film by electroless plating and electroplating.

  More specifically, an acid-base treatment process was performed by immersing the obtained oxide film together with the base material in a treatment liquid containing a base, and then the oxide film was washed with water. Here, a 0.25 mol / L tripotassium citrate aqueous solution was used as the treatment liquid. The pH of this treatment liquid was 8. Moreover, the immersion of the oxide film in the treatment liquid was performed by immersing the oxide film together with the base material in the treatment liquid heated to 40 ° C. for 2 minutes.

  Next, the oxide film was immersed in a solution containing the catalyst together with the base material to perform a catalyst application step, and then the oxide film was washed with water. Here, as a catalyst, an aqueous solution of a palladium complex having an amino acid as a ligand (manufactured by JCU Corporation, trade name: ES-300) is used as a stock solution, and water is used so that the concentration of this stock solution becomes 100 ml / l. Used diluted. Further, the immersion of the oxide film in the solution containing the catalyst was performed by immersing the oxide film together with the base material in a treatment liquid heated to 50 ° C. for 3 minutes. At this time, the amount of the metal-converted catalyst in the portion provided with the catalyst in the surface of the oxide film was as shown in Table 2 described later.

  The oxide film provided with the catalyst was immersed in the solution containing the reducing agent together with the base material, thereby reducing the palladium complex contained in the catalyst to palladium in a metallic state. Here, as the reducing agent, a reducing agent composed of ES-400A solution and ES-400B agent (both manufactured by JCU Corporation, trade name: ES-400) is used, and the concentration of ES-400A solution in 1 l of solution is The mixture was used in water so that the concentration of the ES-400B agent was 10 g / l and 14 g / l. Moreover, the immersion of the oxide film in this solution was performed by immersing the oxide film together with the base material in a treatment liquid heated to 40 ° C. for 2 minutes.

  The oxide film after reducing the catalyst is washed with an unreacted reducing agent by washing with water, and then a metal film is formed by performing electroless plating, and then the thickness of the metal film is obtained by performing electrolytic plating. A metal film forming step for increasing the thickness was performed.

  Among these, the electroless plating treatment was performed by immersing the oxide film together with the base material in an electroless copper plating solution (manufactured by JCU Corporation, trade name: PB-507F) at 30 ° C. for 8 minutes. Here, the thickness of the metal film by the electroless plating treatment is 150 nm, and at this time, the formation rate of the metal film in the electroless copper plating solution is required to be 18 to 19 nm / min. The metal film obtained by the electroless plating treatment was washed with water and air blow dried, then heat treated at 120 ° C. for 10 minutes and dried, and then subjected to electrolytic plating treatment.

For the electrolytic plating treatment, an electrolytic copper plating solution (manufactured by JCU Corporation, trade name: CU BRITE 21) was used, and a metal copper film having a thickness of 20 μm was formed at a current density of ³ A / dm ³ . The oxide film subjected to the electrolytic plating treatment was washed with water and air blow dried.

  Next, a metal film firing step for firing the metal film obtained by the plating treatment was performed to obtain a metal plating structure. Here, the firing of the metal film is such that the temperature rises with a temperature gradient of 10 ° C./min up to a firing temperature of 400 ° C. (second firing temperature) in an inert atmosphere consisting of an atmosphere of nitrogen gas or forming gas. Then, the inside of the furnace was heated and then baked at the second baking temperature for 60 minutes (second baking time). Thereafter, the furnace was naturally cooled until the temperature in the furnace reached room temperature.

<Evaluation of peel strength of metal plating structure>
In order to evaluate the peeling strength (adhesion strength) of the metal films formed on the metal plating structures of Examples 1 to 3 and Comparative Examples 1 to 2, a 90 ° peel test was performed on the metal films (JIS standard H8630). Here, the 90 ° peel test was performed in an environment where the temperature was 24 ° C. and the relative humidity was 30% or less.

  Types of coating agents for forming an oxide film used in Examples 1 to 3 and Comparative Examples 1 to 2, surface roughness Ra of the oxide film in each example, and temperature in the coating film firing step (first firing) Table 2 shows the results of the temperature), the adhesion amount of the palladium catalyst, and the adhesion force measured by the 90 ° peel test.

As a result, as shown in Table 2, in Examples 1 to 3, when the surface roughness Ra of the oxide film was 0.150 nm or more, the palladium complex adhered at least partially to the oxide film, and the palladium complex The amount of palladium deposited on the portion where the metal adhered was 1.7 mg / m ² or more in terms of metal, and a metal film was formed on this palladium. The formed metal film was in close contact with the base material with an adhesion strength of 1.0 [kN / m] or more, and thus it was revealed that the adhesion strength of the metal film to the oxide film was more than that. . On the other hand, in Comparative Examples 1 and 2, when the surface roughness Ra of the oxide film is less than 0.150 nm, swelling occurs between the base material and the metal film (electroless copper). Was easily peeled off from the substrate. From this, it is presumed that the effect of forming a metal film having high adhesion with the oxide film is exhibited by increasing the surface roughness Ra of the oxide film.

  Among these, in Examples 1 and 2, the oxide film forming coating agent (No. 5) was used, the first baking temperature was set to 600 ° C. or lower, and the coating film applied to the substrate was heated to form an oxide film. When the film was formed, the surface roughness Ra of the oxide film was 0.150 nm or more. On the other hand, in Comparative Example 2, the oxide film-forming coating agent (No. 5) was used, the first baking temperature was set to 650 ° C., and the coating film applied to the substrate was heated to form an oxide film. In some cases, the surface roughness Ra of the oxide film was 0.128 nm. From this, it is surmised that the first firing temperature when heating the coating film applied to the substrate is set to a predetermined value or less is one reason why the surface roughness Ra of the high oxide film can be obtained in the examples. Is done.

<< Examples 4 to 8, Comparative Example 3 >>
A coating film was formed on the substrate using the above-described coating agent for forming an oxide film (No. 1-4, 6-7). The other conditions were the same as in Example 1, and a metal plating structure was produced.

  Examples 1, 4 to 8 and type of coating agent for forming oxide film used in Comparative Example 3, the temperature in the coating film firing step (first firing temperature) in each example, and the amount of palladium catalyst attached The results of the adhesion measured by the 90 ° peel test are as shown in Table 3.

As a result, as shown in Table 3, also in Examples 3 to 8, the palladium complex adhered to the oxide film at least partially, and the amount of palladium deposited on the part where the palladium complex adhered was 1.3 mg / m in terms of metal. ^The metal film was formed on this palladium. The formed metal film was in close contact with the base material with an adhesion strength of 0.3 [kN / m] or more, and thus it was revealed that the adhesion strength of the oxide film to the base material was more than that. . In addition, in all of the metal plating structures of Examples 3 to 8, peeling of the metal film from the oxide film hardly occurred.

  Here, the surface roughness Ra of the oxide film produced from the oxide film-forming coating agent (No. 1 to 7) is, as described above, the content of titanium oxide or silicon oxide in the oxide film-forming coating agent. It was about the same regardless of the amount composition. On the other hand, in Comparative Example 3, almost no palladium complex adhered to the oxide film, and no metal film was formed.

  From these facts, the effect of increasing the surface roughness Ra of the oxide film to form a metal film with high adhesion to the oxide film is the composition of a wide range of coating agents for forming an oxide film that can form a metal film. It is inferred that

Claims (4)

An oxide film formed on at least a part of the surface of the substrate,
Titanium atom is essential, silicon atom is optional,
Titanium oxide and silicon oxide are included in a molar ratio of 1: 0 to 3: 2.
An oxide film having a surface roughness Ra of 0.150 nm or more.   The oxide film according to claim 1, which has a thickness of 10 nm to 100 nm. A method for producing an oxide film formed on at least a part of the surface of a substrate,
A coating agent for forming an oxide film comprising an oxide or a precursor thereof, wherein the oxide or the precursor thereof contains titanium atoms and silicon atoms in a molar ratio of 1: 0 to 3: 2. A coating film forming step of forming a coating film by coating on the surface of the substrate;
A coating film baking step of baking the coating film to obtain the oxide film;
Have
A manufacturing method for obtaining an oxide film having a surface roughness Ra of 0.150 nm or more.   The manufacturing method of Claim 3 whose baking temperature in the said coating film baking process is 200 to 600 degreeC.