CONDUCTIVE COMPOSITION AND SUBSTRATE WITH Pt CONDUCTIVE FILM

Abstract

To provide a conductive composition that achieves a Pt conductive film with sufficient conductivity.SOLUTION: A conductive composition disclosed herein is used to from a Pt conductive film on a substrate, the conductive composition containing at least Pt, Si and Al, where the Pt content is 75 mol% or more when the total amount of elements contained in the conductive composition is 100 mol%, and the ratio of the Si molar fraction to the Al molar fraction (Si / Al) is less than 1.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a conductive composition and a substrate with a Pt conductive film. [Background technology]

[0002] Conventionally, conductive compositions have been widely used to form electrodes and wiring patterns of electronic components and the like. The use of platinum (Pt) as a conductive component of such conductive compositions has been considered. Electrodes and wiring mainly composed of platinum are generally formed by printing and firing a paste in which platinum powder or ceramic powder is mixed with resin and a solvent. As a related technique, for example, Patent Document 1 can be mentioned. Patent Document 1 discloses that a conductive powder and a ceramic powder are included, and the average particle diameter in the number-based particle size distribution in the area-equivalent circle diameter obtained by image processing of an image of the conductive powder taken with a scanning electron microscope is 0.12 μm or more and 0.3 μm or less. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-72223 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for higher performance electronic components, and there is a demand for technology that can ensure sufficient conductivity even for conductive films that contain Pt as the main component.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and its main object is to provide a substrate with a Pt conductive film having sufficient conductivity, and a conductive composition for realizing the Pt conductive film. [Means for solving the problem]

[0006] The present inventors conducted various studies to address the above-mentioned problems, and found that when a composition containing Pt element is fired, excessive grain growth occurs during firing, causing Pt particles to be spaced apart from one another after firing (hereinafter, also referred to as "Pt islanding"). When Pt islanding occurs, the conductive path in the fired conductive film tends to be easily broken, and the conductivity tends to be low. In response to this, the present inventors conducted further studies and found that the Pt islanding can be suitably suppressed by preparing a conductive composition that contains Si and Al in addition to Pt, and contains more Al than Si in terms of molar fraction.

[0007] The conductive composition disclosed herein has been made based on the above findings. That is, the conductive composition disclosed herein is a conductive composition for forming a Pt conductive film on a substrate, and contains at least Pt, Si, and Al, the content of Pt is 75 mol% or more when the total amount of elements contained in the conductive composition is taken as 100 mol%, and the ratio of the molar fraction of Si to the molar fraction of Al (Si / Al) is less than 1.

[0008] According to this configuration, the formation of islands of Pt in the conductive film after firing is suitably suppressed, and therefore a conductive composition that forms a Pt conductive film having sufficient conductivity can be realized.

[0009] In a preferred embodiment of the conductive composition disclosed herein, the ratio (Si / Al) is 0.1 or more and 0.7 or less. According to this configuration, a conductive film having more suitable conductivity can be realized.

[0010] In a preferred embodiment of the conductive composition disclosed herein, the content of Al is 10 mol % or more and 15 mol % or less when the total amount of elements contained in the conductive composition is taken as 100 mol %. With this configuration, the effects of the technology disclosed herein can be exerted to a high level.

[0011] In a preferred embodiment of the conductive composition disclosed herein, the content of Si is 2 mol % or more and 7 mol % or less when the total amount of elements contained in the conductive composition is taken as 100 mol %. According to this configuration, the effects of the technology disclosed herein can be exerted more stably.

[0012] In a preferred embodiment of the conductive composition disclosed herein, the conductive composition further contains Rh, and the content of Rh is 0.1 mol % or more and 1 mol % or less when the total amount of elements contained in the conductive composition is taken as 100 mol %. According to this configuration, a conductive film having more suitable conductivity can be realized.

[0013] The present invention also provides a substrate with a Pt conductive film. The substrate with a Pt conductive film disclosed herein includes a ceramic substrate and a Pt conductive film disposed on the ceramic substrate and made of a sintered body of the conductive composition. As described above, the conductive composition disclosed herein effectively suppresses the formation of Pt islands, and therefore a conductive film made of a sintered product of such a conductive composition can have sufficient conductivity.

[0014] In a preferred embodiment of the substrate with a Pt conductive film disclosed herein, the average thickness of the Pt conductive film is 1 μm or less, and the volume resistivity of the Pt conductive film is 10 Ω·cm or less. According to this configuration, both thin film thickness and excellent electrical conductivity are preferably achieved. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A preferred embodiment of the technology disclosed herein will be described below. Matters other than those specifically mentioned in this specification that are necessary for implementation (for example, a method for manufacturing a ceramic substrate to which a conductive composition is applied) can be understood based on the technical content taught by this specification and the general technical common sense of a person skilled in the art in the relevant field. The content of the technology disclosed here can be implemented based on the content disclosed in this specification and the technical common sense of the relevant field. In this specification, the expression "A to B" indicating a range means A or more and B or less.

[0016] <Conductive composition> The conductive composition disclosed herein (hereinafter, simply referred to as the "composition") is used to form a platinum-based conductive film (Pt conductive film) on a substrate. The conductive composition disclosed herein contains at least platinum (Pt), silicon (Si), and aluminum (Al), and the content of Pt is 75 mol % or more when the entire conductive composition is taken as 100 mol %. By firing such a conductive composition at a high temperature (for example, 500° C. or more, preferably 800° C. or more), a Pt-based conductive film can be formed on a substrate. In addition, the conductive composition disclosed herein has a ratio of the molar fraction of Si to the molar fraction of Al (Si / Al) of less than 1. By containing Al and Si at a specific molar fraction ratio, a conductive film that is Pt-based but has sufficient conductivity can be realized. Furthermore, by using the conductive composition disclosed herein, a Pt conductive film that is a thin film of 1 μm or less can be provided.

[0017] The reason why such an effect is obtained is not particularly limited, but is presumed to be as follows. Pt element is more likely to undergo particle growth by firing than other metal elements such as silver (Ag) and nickel (Ni). For this reason, when a composition containing Pt element is fired, Pt particles are arranged apart from each other, so-called Pt island formation occurs, and the conductivity tends to be low. In contrast, the conductive composition disclosed herein contains Si and Al in addition to Pt. While Si and Al have the function of favorably adhering the conductive film to the substrate after firing, they do not have conductivity. However, by preparing the composition so that it contains more Al than Si in molar fraction, the particle growth of Pt can be favorably suppressed. This makes it possible to realize a Pt conductive film that has sufficient conductivity and thinness.

[0018] As described above, the conductive composition disclosed herein contains at least Pt, Si, and Al. Hereinafter, various components that may be contained in the conductive composition disclosed herein will be specifically described.

[0019] Platinum (Pt) is a material for forming a film having high electrical conductivity (conductivity) in the sintered body of the conductive composition (hereinafter, simply referred to as "conductive film"). Pt is a major component of the elements contained in the conductive composition (i.e., Pt accounts for 50 mol % or more of the elements contained in the conductive composition). For example, Pt is preferably contained in the conductive composition as a constituent element of Pt resinate. More preferably, Pt is contained in the conductive composition in the form of platinum resin sulfide balsam. This makes it possible to preferably realize the conductivity and thinning of the conductive film.

[0020] The content of the Pt element is preferably 75 mol% or more, more preferably 80 mol% or more, when the entire conductive composition (all elements contained in the conductive composition) is taken as 100 mol%. This allows the amount of Pt in the conductive composition to be sufficiently secured. On the other hand, the conductive composition disclosed herein contains at least Si element and Al element in addition to Pt element from the viewpoint of improving conductivity. Therefore, from this viewpoint, the upper limit of the content of the Pt element is, for example, preferably 90 mol% or less, may be 87 mol% or less, or may be 85 mol% or less, when the entire conductive composition is taken as 100 mol%. This allows the conductive film to have suitable conductivity. The content of each element in such a conductive composition can be measured, for example, by ICP emission spectrometry.

[0021] Although not particularly limited, it is preferable that the conductive composition does not substantially contain Pt powder. This can prevent the conductive film from becoming thick due to aggregation of Pt powder, and can further preferably realize a thin conductive film. In this specification, "Pt powder" refers to an aggregate of spherical, scaly, or plate-shaped materials containing Pt as the main component. In addition, "substantially free" refers to not intentionally adding Pt powder. Therefore, when a component that can be interpreted as Pt powder is contained in a small amount due to raw materials or manufacturing process, etc., it is included in the concept of "substantially free" in this specification. For example, when the content of Pt powder in the conductive composition is 0.01 wt% or less (preferably 0.005 wt% or less, more preferably 0.001 wt% or less, even more preferably 0.0005 wt% or less, and particularly preferably 0.0001 wt% or less), it can be said to be "substantially free".

[0022] Silicon (Si) and aluminum (Al) are glass components that become oxides after firing. The conductive composition contains Si and Al, so that the conductive film can be suitably arranged on the substrate. In addition, as described above, by containing more Al than Si in molar fraction, the grain growth of Pt during firing can be suppressed, and the conductive film after firing can have sufficient conductivity. The ratio of the molar fraction of Si to the molar fraction of Al in the conductive composition (Si / Al) is less than 1, and is preferably 0.9 or less, more preferably 0.7 or less, and even more preferably 0.66 or less. In addition, although not particularly limited, the ratio of the molar fraction of Si to the molar fraction of Al (Si / Al) is, for example, preferably 0.1 or more, more preferably 0.15 or more, even more preferably 0.2 or more, and may be 0.4 or more. From the viewpoint of realizing more suitable electrical conductivity, the ratio of the molar fraction of Si to the molar fraction of Al in the conductive composition (Si / Al) is preferably 0.1 or more and 0.7 or less, and more preferably 0.2 or more and 0.7 or less.

[0023] The content ratio of the Si element and the content ratio of the Al element in the conductive composition are not particularly limited as long as they satisfy the above-mentioned molar fraction ratio. The content ratio of the Si element is preferably 2 mol% or more and 7 mol% or less, and more preferably 2.8 mol% or more and 7 mol% or less, when the entire conductive composition is taken as 100 mol%. The content ratio of the Al element is preferably 10 mol% or more and 15 mol% or less, and may be 10 mol% or more and 12 mol% or less, when the entire conductive composition is taken as 100 mol%. This can suppress excessive grain growth of Pt during firing and improve conductivity.

[0024] It is preferable that Si is contained in the conductive composition as, for example, a constituent element of Si resinate. More preferably, Si is contained in the conductive composition in the form of a silicon resin acid salt. It is also preferable that Al is contained in the conductive composition as, for example, a constituent element of Al resinate or as a chelate compound. Examples of chelate compounds containing Al include aluminum ethyl acetoacetate diisopropylate (ALCH), aluminum tris(ethyl acetoacetate), aluminum alkyl acetoacetate diisopropylate, aluminum monoacetylacetonate bis(ethyl acetoacetate), aluminum tris(acetylacetonate), and the like. It is preferable that Al is contained in the conductive composition in the form of an aluminum resin acid salt or the above-mentioned chelate compound. This allows each component to be suitably dispersed in the conductive composition.

[0025] The conductive composition may further contain rhodium (Rh) in addition to the above-mentioned Pt, Si, and Al. Rh can have a certain conductivity in the conductive film. In addition, Rh can suppress excessive particle growth of Pt during firing. Therefore, by the conductive composition containing Rh, the conductivity of the conductive film can be further improved. When the conductive composition contains Rh, it is preferable that Rh is contained in the conductive composition as a constituent element of Rh resinate, for example. More preferably, Rh is contained in the conductive composition in the form of rhodium resin sulfide balsam.

[0026] Although not particularly limited, when the conductive composition contains Rh, the content of Rh element is preferably 0.1 mol % to 1.5 mol %, more preferably 0.1 mol % to 1 mol %, and may be 0.2 mol % to 0.9 mol %, when the entire conductive composition is taken as 100 mol %, which can more suitably improve the conductivity of the conductive film.

[0027] The conductive composition may further contain bismuth (Bi) in addition to the above-mentioned Pt, Si, and Al. Bi is a glass component that becomes an oxide after firing. When the conductive composition contains Bi, the adhesive strength between the conductive film and the substrate can be improved. When the conductive composition contains Bi, it is preferable that Bi is contained in the conductive composition as a constituent element of Bi resinate, for example. More preferably, Bi is contained in the conductive composition in the form of bismuth resinate.

[0028] Although not particularly limited, when the conductive composition contains Bi, the content of Bi element is preferably 0.1 mol % to 1.5 mol %, more preferably 0.1 mol % to 1 mol %, and may be 0.2 mol % to 0.8 mol %, when the entire conductive composition is taken as 100 mol %, which can suitably improve the adhesive strength between the conductive film and the substrate.

[0029] The conductive composition may contain other elements other than the above-mentioned elements within a range that does not impair the effects of the technology disclosed herein. Examples of such other elements include yttrium (Y), zirconium (Zr), samarium (Sm), calcium (Ca), barium (Ba), chromium (Cr), and tin (Sn). When the entire conductive composition is taken as 100 mol%, the content of the other elements may be, for example, 5 mol% or less, or 3 mol% or less, or the other elements may not be contained.

[0030] The elements that may be contained in the conductive composition disclosed herein have been described above. In addition to the above-mentioned components, the conductive composition disclosed herein is preferably added with various components in consideration of the fixation to the surface of the substrate and the formability of the conductive film. Hereinafter, other components that may be contained in the conductive composition disclosed herein will be described. However, the other components described below can be any conventionally known components that can be used in the conductive composition without any particular restrictions, so long as they do not significantly impede the effects of the technology disclosed herein. That is, the conductive composition disclosed herein can appropriately change the components other than the above-mentioned essential elements depending on the application.

[0031] First, as described above, the conductive composition disclosed herein may contain each of the elements in the form of a metal resinate. In this case, the conductive composition contains an organic compound for forming the metal resinate. The organic compound may be any conventionally known resin material that can be used to produce a metal resinate, without any particular limitation. Examples of such resin materials include carboxylic acids with a high carbon number (e.g., 8 or more carbon atoms), such as octylic acid (2-ethylhexanoic acid), abietic acid, naphthenic acid, stearic acid, oleic acid, linoleic acid, and neodecanoic acid; sulfonic acids; resin acids contained in rosin; resin sulfur balsam containing essential oil components such as turpentine oil and lavender oil, alkyl mercaptides (alkyl thiolates), aryl mercaptides (aryl thiolates), mercaptocarboxylic acid esters, and alkoxides.

[0032] In addition, in a conductive composition containing each element in the form of a metal resinate, it is preferable to use an organic solvent that disperses or dissolves the metal resinate. As such an organic solvent, those that have been used in resinate pastes or liquid gold solutions can be used without any particular limitation. Examples of the organic solvent include 1,4-dioxane, 1,8-cineole, 2-pyrrolidone, 2-phenylethanol, N-methyl-2-pyrrolidone, p-tolualdehyde, benzyl benzoate, butyl benzoate, eugenol, caprolactone, geraniol, methyl salicylate, cyclohexanone, cyclohexanol, cyclopentyl methyl ether, citronellal, di(2-chloroethyl)ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, dihydrocarvone, dibromomethane, dimethyl sulfoxide, dimethylformamide, nitrobenzene, pyrrolidone, propylene glycol monophenyl ether, pulegone, benzyl acetate, benzyl alcohol, benzaldehyde, turpentine oil, and lavender oil. These organic solvents may be used alone or in combination. Metal resinates are commercially available as resinate pastes, for example, and such resinate pastes may be used as they are.

[0033] The weight ratio of the solvent that can be contained in the conductive composition is not particularly limited because the suitable range varies depending on the application method of the conductive composition, and may be adjusted as appropriate. For example, the content of the solvent in the conductive composition may be approximately 10 wt% to 50 wt%. As an example, when applying by inkjet, the content of the solvent in the conductive composition is preferably, for example, 10 wt% to 50 wt%. As another example, when applying by brush, the content of the solvent in the conductive composition is preferably, for example, 10 wt% to 30 wt%.

[0034] The viscosity of the conductive composition may be appropriately adjusted according to the coating method of the conductive composition and is not particularly limited. For example, the viscosity of the conductive composition may be about 10 mPa·s to 500 mPa·s. Note that the viscosity of the conductive composition can be appropriately adjusted by the amount of the solvent, the addition of resin balsam, etc.

[0035] In addition, the conductive composition disclosed herein may additionally contain other components as appropriate as long as the effects of the technology disclosed herein are not significantly impaired. Examples of additional components include organic binders, protective materials, surfactants, dispersants, thickeners, pH adjusters, preservatives, defoamers, plasticizers, stabilizers, antioxidants, etc.

[0036] The conductive composition disclosed herein can be produced, for example, by mixing a material containing a desired metal element in a predetermined ratio so as to contain at least Pt, Si, and Al. Note that the form of the components contained in the conductive composition disclosed herein is not limited to metal resinates, and may be complexes, polymers, or fine particles. When each component takes a form other than a metal resinate, it is preferable to appropriately change the above-described solvent and additional components according to the form of each component. For example, when a noble metal component and a matrix-forming component are contained in a form that does not dissolve in a solvent such as fine particles, it is preferable to select a solvent capable of appropriately dispersing the fine particles and add a dispersant or the like as an additional component.

[0037] <Substrate with Pt conductive film> Hereinafter, an embodiment of the substrate with a Pt conductive film disclosed herein will be described. The above conductive composition can form a conductive film on the substrate by firing at a high temperature (for example, 500°C or higher, preferably 800°C or higher). Therefore, the substrate is preferably made of a material that does not cause damage, excessive deformation, etc. when fired at a high temperature. Examples of such a substrate include ceramic substrates mainly composed of ceramics.

[0038] The substrate with Pt conductive film disclosed herein includes a ceramic substrate and a Pt conductive film disposed on the substrate. The Pt conductive film is formed of a sintered body of the conductive composition described above. The substrate with Pt conductive film includes, for example, the Pt conductive film on a substrate mainly composed of ceramics. The substrate with Pt conductive film may also include a coating layer on the substrate for protecting the substrate and improving adhesion to the Pt conductive film. The coating layer may include various additives such as glaze, antioxidant, antistatic agent, lubricant, plasticizer, and colorant.

[0039] The substrate is a molded body mainly composed of ceramics (for example, a molded body with a ceramic content of 50 mass% or more). Examples of ceramics that constitute such a substrate include silica (SiO2), alumina (Al2O3), zirconia (ZrO2), magnesia (MgO), titania (TiO2), ceria (CeO2), and yttria (Y2O3). The thickness, shape, hardness, color, and other properties of the substrate can be appropriately changed depending on the application of the Pt conductive film-coated substrate, and detailed descriptions are omitted since they do not limit the technology disclosed herein. Note that the chemical formulas shown in parentheses after the above substance names indicate the representative compositions of the substances, and are not intended to limit the composition of the actual ceramics to those of the chemical formulas.

[0040] The substrate with a Pt conductive film disclosed herein has a Pt conductive film composed of the above composition. The Pt conductive film can be formed on the surface of the substrate or the surface of the coating layer. The Pt conductive film can be formed in a predetermined pattern. The Pt conductive film may be provided on only one side of the substrate, or on both sides of the substrate. The Pt conductive film may be provided on only a part of the substrate, or may be provided over the entire surface of the substrate. The conductive film of the substrate with a Pt conductive film disclosed herein has a reduced volume resistivity and excellent conductivity. Furthermore, such a Pt conductive film is thin (for example, the average thickness of the Pt conductive film is 1 μm or less).

[0041] Although not particularly limited, the conductivity of the Pt conductive film can be obtained, for example, such that the volume resistivity after firing at 800°C for 10 minutes is 1×10 1 Ω·cm or less. The volume resistivity is preferably 1×10 -1 Ω·cm or less, and more preferably 1×10 -2 Ω·cm or less.

[0042] The average thickness of the Pt conductive film is preferably, for example, 1 μm or less, more preferably 700 nm or less, and even more preferably 500 nm or less. The lower limit of the average thickness of the Pt conductive film is not particularly limited, but is preferably, for example, 10 nm or more, more preferably 20 nm or more, and may be 30 nm or more. By forming a conductive film using the conductive composition disclosed herein, it is possible to achieve both thinning and sufficient conductivity. The average thickness of the conductive film can be appropriately adjusted, for example, by the coating method.

[0043] <Method for manufacturing a substrate with a Pt conductive film> Next, an example of a method for manufacturing a substrate with a Pt conductive film disclosed herein will be described. Note that the substrate with a Pt conductive film disclosed herein is not limited to those manufactured by the following manufacturing method.

[0044] The substrate with a Pt conductive film disclosed herein can be preferably manufactured by a manufacturing method including preparing a substrate, preparing the conductive composition disclosed herein, supplying the conductive composition onto the substrate, and firing the substrate onto which the conductive composition has been supplied. First, prepare a desired substrate. For example, a substrate can be produced by molding and firing a substrate material kneaded with the above-described ceramic material. Next, prepare the conductive composition. Since the preparation of the conductive composition is as described above, detailed description thereof will be omitted.

[0045] Next, the conductive composition is supplied onto the prepared substrate. The method of supplying the conductive composition is not particularly limited. For example, various printing methods such as spin coating, inkjet printing, brush coating, gravure printing, screen printing, etc. can be adopted. Then, the substrate to which the conductive composition has been supplied is fired. Thereby, a conductive film can be formed on the substrate. The firing is preferably performed at a temperature in a firing furnace of 500°C to 1200°C, more preferably 800°C to 1000°C. The firing time is not particularly limited, but is preferably about 1 minute to 60 minutes, more preferably about 10 minutes to 30 minutes.

[0046] In this manner, a Pt conductive film-attached substrate having a conductive film with good conductivity can be realized. In addition, the conductive film of the Pt conductive film-attached substrate can be made thin. The Pt conductive film-attached substrate can be used, for example, in electronic materials (components), semiconductor device-related products, and as a replacement for plating. <Test Example> Test examples relating to the technology disclosed herein will be described below, but it is not intended that the technology disclosed herein be limited to such test examples.

[0047] 1. Preparation of Conductive Composition In this test, the elements were mixed to obtain the composition shown in Table 1. Each value in Table 1 indicates the content (mol%) of each element when the total of the elements contained in the conductive composition is 100 mol%. Specifically, various raw materials were mixed in an ointment jar and mixed for 2 minutes at a rotation speed of 1800 rpm using a mixer (product name: Rotating and Revolving Awatori Mixer) manufactured by Thinky Corporation. In this way, the conductive compositions of Examples 1 to 8 were prepared. The viscosity of the conductive compositions was 10 to 15 mPa s. The raw materials of each element used here are shown below. Pt: Pt resinate (platinum resin sulfide balsam) Si:Si resinate (silicon resin acid salt) Al: Aluminum chelate compound (ALCH) Rh: Rh resinate (rhodium resin sulfide balsam) Bi: Bi resinate (bismuth resinate) Y: Y-resinate (yttrium resinate)

[0048] A white porcelain plate (length: 15 mm, width: 15 mm) with a coating layer (glaze) applied on the surface was prepared as a substrate, and the conductive composition prepared above (any of Examples 1 to 8) was applied (coated) to the entire surface on one side of the white porcelain plate. At this time, the thickness of the Pt conductive film after firing was adjusted to be 1 μm or less (30 nm to 200 nm). A spin coater (Opticoat MS-A-150) manufactured by Mikasa Co., Ltd. was used to apply the conductive composition. The spin coater was set to spin conditions of 3000 rpm to 5000 rpm for 10 seconds so that the Pt conductive film had the above-mentioned film thickness. The white porcelain plate with the conductive composition applied was dried on a hot plate at 60° C. for 1 hour, and then fired at 800° C. for 10 minutes. As a result, the white porcelain plates of Examples 1 to 8 with the Pt conductive film formed on the surface of the substrate were obtained.

[0049] 2.Evaluation of electrical conductivity The volume resistivity (Ω·cm) of the white porcelain flat plates (Examples 1 to 8) on which the Pt conductive film was formed was measured. The volume resistivity was measured using a resistivity meter (Loresta GP MCP-T610) manufactured by Mitsubishi Chemical Analytech Co., Ltd. 1 A conductive film with a resistivity of Ω·cm or less was evaluated as having sufficient conductivity (marked "○" in Table 1). On the other hand, the "O / L" in the table is 1×10 1 This means that the value exceeded Ω·cm, and the conductive film was evaluated as not having sufficient conductivity ("X" in Table 1). The results are shown in Table 1.

[0050] [Table 1]

[0051] As shown in Table 1, it can be seen that the electrical conductivity evaluation is good in Examples 4 to 7. This is presumably because the ratio of the molar fraction of Si to the molar fraction of Al (Si / Al) is adjusted to less than 1, which makes it possible to suitably suppress the grain growth of Pt during firing and to suppress the occurrence of island formation of Pt in the conductive film after firing. On the other hand, it can be seen that the electrical conductivity is not good in Example 1, which does not contain Al, Examples 2 and 3, in which the molar fraction of Al is less than the molar fraction of Si, and Example 8, which does not contain Si. This is presumably because the effect of Si and Al in suppressing the grain growth of Pt during firing is not fully exerted.

[0052] Although specific examples of the technology disclosed herein have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples exemplified above.

[0053] The technology disclosed herein includes the following items 1 to 7. The following items 1 to 7 are not limited to the above-described embodiment.

[0054] Item 1 relates to a conductive composition. The conductive composition in item 1 is A conductive composition for forming a Pt conductive film on a substrate, comprising: Contains at least Pt, Si, and Al; The content of Pt is 75 mol % or more when the total amount of elements contained in the conductive composition is 100 mol %, The ratio of the mole fraction of Si to the mole fraction of Al (Si / Al) is less than 1.

[0055] Item 2 is the conductive composition according to item 1, The ratio (Si / Al) is 0.1 or more and 0.7 or less.

[0056] Item 3 is the conductive composition according to item 1 or 2, The content of Al is 10 mol % or more and 15 mol % or less when the total amount of elements contained in the conductive composition is taken as 100 mol %.

[0057] Item 4 is the conductive composition according to any one of items 1 to 3, The content of Si is 2 mol % or more and 7 mol % or less when the total amount of elements contained in the conductive composition is taken as 100 mol %.

[0058] Item 5 is the conductive composition according to any one of items 1 to 4, Further containing Rh, The content of Rh is 0.1 mol % or more and 1 mol % or less when the total amount of elements contained in the conductive composition is taken as 100 mol %.

[0059] Item 6 relates to a substrate with a Pt conductive film. The substrate with a Pt conductive film in item 6 is A ceramic substrate; and a Pt conductive film disposed on the ceramic substrate and made of a sintered body of the conductive composition according to any one of items 1 to 5.

[0060] Item 7 is the substrate with a Pt conductive film according to item 6, The average thickness of the Pt conductive film is 1 μm or less, The volume resistivity of the Pt conductive film is 10 Ω·cm or less.

Claims

1. A conductive composition for forming a Pt conductive film on a substrate, comprising: Contains at least Pt, Si and Al; The content of Pt is 75 mol % or more when the total amount of elements contained in the conductive composition is 100 mol %, A conductive composition, wherein the ratio of the mole fraction of Si to the mole fraction of Al (Si / Al) is less than 1.

2. The conductive composition according to claim 1 , wherein the ratio (Si / Al) is 0.1 or more and 0.7 or less.

3. 3. The conductive composition according to claim 1, wherein the content of Al is 10 mol % or more and 15 mol % or less when all elements contained in the conductive composition are taken as 100 mol %.

4. 3. The conductive composition according to claim 1, wherein the content of Si is 2 mol % or more and 7 mol % or less when all elements contained in the conductive composition are taken as 100 mol %.

5. further comprising Rh, 3. The conductive composition according to claim 1, wherein the content of Rh is 0.1 mol % or more and 1 mol % or less when all elements contained in the conductive composition are taken as 100 mol %.

6. A ceramic substrate; A Pt conductive film disposed on the ceramic substrate and made of a sintered body of the conductive composition according to claim 1 or 2; A substrate with a Pt conductive film.

7. The average thickness of the Pt conductive film is 1 μm or less, 7. The substrate with a Pt conductive film according to claim 6, wherein the volume resistivity of the Pt conductive film is 10 Ω·cm or less.

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