Method for producing photosensitive composition, method for producing electronic component, and device for determining compounding ratio of organic components in photosensitive composition

Abstract

According to the present invention, a method for producing a photosensitive composition is provided, comprising the following steps: a step of measuring the particle size of a conductive powder to be used to obtain an actual value (step S1); a step of comparing the actual value with a first correlation equation for an arbitrary factor that varies in correlation between the particle size of the conductive powder and a displacement of the particle size, and confirming a predicted deviation value of the factor from a predetermined target level (step S2); and a step of determining the blending ratio of the organic component based on a second correlation equation for the factor in the first correlation equation and an arbitrary organic component contained in the photosensitive composition and having a blending ratio that varies in correlation with the factor, so as to eliminate the predicted deviation value (step S3).

Description

Technical Field

[0001] The present invention relates to a method for producing a photosensitive composition, a paste-like photosensitive composition, a method for producing an electronic component, an electronic component, a device for determining a blending ratio of an organic component in a photosensitive composition, and a computer program.

[0002] It should be noted that this application claims priority based on Japanese Patent Application No. 2019-128628, filed on July 10, 2019, the entire contents of which are incorporated herein by reference. Background Art

[0003] In the manufacture of electronic components such as inductors, the following method is known: a photosensitive composition containing conductive powder, a photopolymerizable resin and a photopolymerization initiator is used to form a conductive layer on a substrate by photolithography (for example, refer to patent documents 1 and 2). In the above method, first, a photosensitive composition is applied to the substrate and dried to form a conductive film (conductive film forming process). Then, a photomask with a prescribed opening pattern is covered on the conductive film after the above formation, and the conductive film is exposed through the photomask (exposure process). Thus, the exposed part of the conductive film is photocured. Then, the unexposed part after being shielded by the photomask is corroded and removed in a developer (development process). Then, the conductive film having the desired pattern is baked and sintered on the substrate (baking process). According to the photolithography method including the above process, a fine conductive layer can be formed compared to various existing printing methods.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 5163687

[0007] Patent Document 2: International Publication No. 2015 / 122345 Summary of the Invention

[0008] However, in recent years, the miniaturization and high performance of various electronic devices have been rapidly promoted, and the electronic components installed in the electronic devices are also required to be further miniaturized and high-densified. Along with this, when manufacturing electronic components such as stacked chip inductors, the conductive layer is required to have low resistance and thin lines (narrowing). More specifically, the line width of the wiring constituting the conductive layer and the space between adjacent wirings (line width / line spacing: L / S) are required to be reduced to 30μm / 30μm or less, and further to 20μm / 20μm or less. If the L / S of the conductive layer is small, a slight increase in the line width of the wiring will cause adjacent wirings to connect to each other and cause a short circuit, or conversely, a slight decrease in the line width of the wiring will make it easy to peel off and break. Therefore, in electronic components such as stacked chip inductors, if the fluctuation of the line width is large, it will have an adverse effect on the characteristics of the product or reduce the yield. Therefore, from the perspective of mass production, it is necessary to suppress the fluctuation in line width of the conductive film after development to reduce the fluctuation in line width of the conductive layer after firing, thereby forming fine wiring in electronic components with good reproducibility.

[0009] The present invention has been made in view of the above-mentioned circumstances, and its object is to provide a photosensitive composition capable of reproducibly forming thin wiring lines of a desired line width. Another related object is to provide a method for manufacturing an electronic component and an electronic component. Another related object is to provide a device and a computer program for determining the blending ratio of organic components in a photosensitive composition.

[0010] The present inventors have conducted extensive research on the various components of the photosensitive composition and have newly determined that the particle size of the conductive powder is an important factor in determining the line width after development. Figure 1 (A) is a schematic side view showing the exposure process when using the conductive powder 1A with a relatively large particle size. Figure 1 As shown in (A), if the particle size of the conductive powder 1A is large, the light penetrating from the opening of the photomask into the interior of the conductive film is reflected on the surface of the conductive powder 1A, and light scattering is likely to occur. Therefore, light becomes easy to diffuse in the horizontal direction of the conductive film. As a result, the light also reaches the periphery of the opening of the photomask (the part shielded by the photomask), and the line width is likely to become thicker than the opening width of the photomask. In contrast, Figure 1 (B) is a schematic side view showing the exposure process when using the conductive powder 1B with a relatively small particle size. Figure 1 As shown in (B), if the particle size of the conductive powder 1B is small, the light penetrating from the opening of the photomask into the interior of the conductive film is not easily reflected on the surface of the conductive powder 1B, and the scattering of light is suppressed. Therefore, the light is not easily diffused in the horizontal direction of the conductive film, and the light is not easily diffused in the horizontal direction of the conductive film. Figure 1The line width is relatively easy to become thinner compared to (A). Therefore, it can be said that in order to stabilize the line width, it is desirable to highly manage the particle size of the conductive powder used.

[0011] However, according to the investigation of the present inventors, the particle size of the conductive powder also varies when the manufacturing batch (product unit) is different. For example, the present inventors believe that: several manufacturing batches of conductive powder with an average particle size (nominal value) of 2.9μm were purchased, and the average particle size was actually measured. As a result, the average particle size (measured value) deviated from the nominal value by about ±0.4μm. It is believed that this variation is caused by fluctuations in the manufacturing process. Therefore, in this state, it is expected that the line width will fluctuate according to the fluctuation of the average particle size (measured value) of the conductive powder. Therefore, the present inventors believe that it is possible to buffer the fluctuation of the line width that may be caused by the fluctuation between the manufacturing batches of the conductive powder when manufacturing the photosensitive composition. Moreover, after repeated further research, the present invention was conceived.

[0012] According to the present invention, a method for producing a photosensitive composition containing a conductive powder at a predetermined mixing ratio is provided. This method includes the following steps: measuring the particle size of the conductive powder to obtain a measured value; comparing the measured value with a pre-prepared first correlation equation, i.e., a first correlation equation relating the particle size of the conductive powder to an arbitrary factor that varies due to light absorption or photocuring of the conductive film and varies in correlation with the displacement of the particle size, to determine a predicted deviation of the factor from a predetermined target level; and determining the mixing ratio of the organic component based on a pre-prepared second correlation equation, i.e., a second correlation equation relating the factor in the first correlation equation to an arbitrary organic component contained in the photosensitive composition and whose mixing ratio varies in correlation with the factor, so as to eliminate the predicted deviation.

[0013] In the above-mentioned manufacturing method, the particle size of the conductive powder used in manufacturing the photosensitive composition is measured in advance, and a predicted deviation from the target level is simulated. Based on the simulation results, the blending ratio of the organic components is determined in a manner that eliminates the predicted deviation. This minimizes the impact of variations between manufacturing batches of the conductive powder, and can suppress fluctuations in line width caused by differences in manufacturing batches of the conductive powder. Consequently, a photosensitive composition can be provided that does not require such rigorous management of the conductive powder particle size. For example, even if the production batch of purchased conductive powder is switched midway, the desired line width can be stably achieved. This improves yield, mass production, and productivity.

[0014] In a preferred embodiment disclosed herein, the organic component is an organic component that adjusts at least one of the light absorptivity and photopolymerizability of the photosensitive composition. The organic component may be at least one of a photopolymerization initiator, a light absorber, and a polymerization inhibitor. The organic component may be a photopolymerization initiator. This allows, for example, the blending ratio of the photocurable component (a component that cures through polymerization, such as a photocurable compound) in the photosensitive composition to be stabilized, thereby achieving the effects of the technology disclosed herein while maintaining the overall properties of the conductive film, such as its adhesion to the substrate, at a high level.

[0015] In a preferred embodiment disclosed herein, the factor in the first correlation equation is the line width, film thickness, electrode cross-sectional area, curing shrinkage, or resistance value of the conductive film. The factor in the first correlation equation may be the line width.

[0016] In a preferred embodiment disclosed herein, the second correlation equation is expressed as a linear function. In a linear function, two variables are in a proportional relationship, so the mixing ratio can be calculated simply and easily.

[0017] In a preferred embodiment disclosed herein, the conductive powder contains silver-based particles, thereby achieving a conductive layer having an excellent balance between cost and low resistance.

[0018] In one preferred embodiment disclosed herein, the first conductive powder is a core-shell particle comprising a metal material forming a core and a ceramic material covering at least a portion of the surface of the core. This further improves the stability of the conductive powder in the photosensitive composition and enables the realization of a highly durable conductive layer. Furthermore, in applications such as forming a conductive layer on a ceramic substrate (ceramic substrate) to manufacture ceramic electronic components, the integrity of the conductive layer with the ceramic substrate can be improved.

[0019] Furthermore, the present invention provides a method for manufacturing an electronic component, comprising applying the photosensitive composition to a substrate, photocuring and etching the composition, and then firing the resulting fired product to form a conductive layer comprising the photosensitive composition. This method allows for the suitable manufacture of compact and / or high-density electronic components equipped with a conductive layer.

[0020] Furthermore, according to the present invention, there is provided an apparatus for determining the blending ratio of an organic component to a photosensitive composition containing a conductive powder at a predetermined blending ratio. The blending ratio determining apparatus includes: an input unit for accepting user input of the type and measured values ​​of the conductive powder to be used; a storage unit for storing a pre-prepared first correlation equation, i.e., a first correlation equation for the particle size of the conductive powder and an arbitrary factor that varies due to light absorption or photocuring of the conductive film and varies in correlation with the displacement of the particle size; and a pre-prepared second correlation equation for the factor in the first correlation equation and an arbitrary organic component contained in the photosensitive composition, the blending ratio of which varies in correlation with the factor; a first calculation unit for calculating, based on the first correlation equation and the measured values ​​input from the input unit, a predicted deviation value of the factor in the first correlation equation from a predetermined target level; and a second calculation unit for calculating, based on the second correlation equation, a blending ratio of the organic component in the second correlation equation that eliminates the predicted deviation value. This prevents calculation errors, and allows even an operator who is not familiar with the operation to easily determine the blending ratio of the organic components.

[0021] Furthermore, the present invention provides a computer program configured to cause a computer to operate as the aforementioned mixing ratio determination device. This prevents calculation errors and allows, for example, even an operator unfamiliar with the operation to easily determine the mixing ratio of the organic components.

[0022] Furthermore, the present invention provides an electronic component comprising a conductive layer comprising a calcined product of the above-mentioned photosensitive composition. The photosensitive composition can stably realize a conductive layer having fine wiring. Therefore, the photosensitive composition can suitably realize a compact and / or high-density electronic component having a conductive layer.

[0023] Furthermore, the present invention provides a photosensitive composition in a paste form, wherein the photosensitive composition comprises an organic dispersion medium. By preparing the photosensitive composition in a paste form, the photosensitive composition can be easily applied to a desired location on a substrate in a desired form by, for example, coating or printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic side views of a conductive film, (A) is a side view when a conductive powder having a large average particle size is used, and (B) is a side view when a conductive powder having a small average particle size is used.

[0025] Figure 2 This is a flow chart of a manufacturing method according to one embodiment of the present invention.

[0026] Figure 3A cross-sectional view schematically showing the structure of a stacked chip inductor.

[0027] Figure 4 Functional block diagram of a device for determining a mixing ratio.

[0028] Figure 5 This is an example of the first correlation equation of Example 1.

[0029] Figure 6 This is an example of the second correlation formula for photopolymerization initiators.

[0030] Figure 7 A chart comparing actual line widths.

[0031] Figure 8 This is an example of the first correlation equation of Example 2.

[0032] Figure 9 This is an example of the first correlation equation of Example 2.

[0033] Figure 10 This is an example of the second correlation equation for the ultraviolet absorber.

[0034] Figure 11 This is an example of the second correlation equation for the photoinhibitor. DETAILED DESCRIPTION

[0035] The following describes preferred embodiments of the present invention. It should be noted that matters other than those specifically mentioned in this specification and necessary for implementing the present invention (e.g., methods for forming conductive films and conductive layers, methods for manufacturing electronic components, etc.) can be understood based on the technical content exemplified in this specification and the general technical knowledge of those skilled in the art. The present invention can be implemented based on the content disclosed in this specification and the general technical knowledge in this field.

[0036] It should be noted that, in this specification, "conductive film" refers to a film-like body (dried product) obtained by drying a photosensitive composition at a temperature below the boiling point of the organic component (approximately below 200°C, for example, below 100°C). The conductive film includes all unfired (before firing) film-like bodies. The conductive film may be an uncured material before photocuring, or a cured material after photocuring. In addition, in this specification, "conductive layer" refers to a sintered body (fired product) obtained by firing a photosensitive composition at a temperature above the sintering temperature of the conductive powder. The conductive layer includes wiring (linear body), wiring pattern, and solid pattern. In addition, the expression "A to B" indicating a range in this specification includes the meaning of greater than A and less than B, "preferably greater than A" and "preferably less than B".

[0037] 《Method for producing photosensitive composition》

[0038] In this embodiment, a manufacturing method is described in which line width is used as a factor of the target level (i.e., line width is the target characteristic), particularly against the backdrop of line width being an important required characteristic. Specifically, in this embodiment, the predetermined target level is represented by "target line width," and the predicted deviation value is represented by "predicted deviation width." However, as will be described later, the target level factor is not limited to line width, as long as it is derived from the light absorption and photocuring degree of the conductive film.

[0039] Figure 2 This is a flow chart of the production method of this embodiment. The production method disclosed herein is a method for producing a photosensitive composition containing a conductive powder at a predetermined mixing ratio. In this embodiment, the production method includes the following steps: (Step S1) measuring the average particle size; (Step S2) confirming the predicted deviation width; (Step S3) determining the mixing ratio of the organic component; and (Step S4) preparing the photosensitive composition. Each step is described below in order.

[0040] <(Step S1) Average Particle Diameter Measurement Step>

[0041] In this step, first, the conductive powder used to produce the photosensitive composition is prepared. The conductive powder is a component that imparts conductivity to the conductive layer. The conductive powder can be purchased commercially or prepared in-house using conventionally known methods. The type of conductive powder is not particularly limited; one type can be used alone or in combination of two or more types, depending on the intended application.

[0042] As conductive powder, for example, simple substances of metals such as gold (Au), silver (Ag), copper (Cu), platinum (Pt), palladium (Pd), aluminum (Al), nickel (Ni), ruthenium (Ru), rhodium (Rh), tungsten (W), iridium (Ir), and osmium (Os), and mixtures and alloys thereof can be cited. As alloys, for example, silver alloys such as silver-palladium (Ag-Pd), silver-platinum (Ag-Pt), and silver-copper (Ag-Cu) can be cited. In one suitable embodiment, the conductive powder contains silver-based particles. Silver is relatively cheap and has high electrical conductivity. Therefore, by containing silver-based particles in the conductive powder, a conductive layer with an excellent balance between cost and low resistance can be achieved. It should be noted that in this specification, "silver-based particles" include all particles containing silver components. As an example of silver-based particles, simple substances of silver, the above-mentioned silver alloys, core-shell particles having silver-based particles as cores, such as silver-ceramic core-shell particles, etc. can be cited.

[0043] An organic surface treatment agent may be attached to the surface of the conductive powder. The organic surface treatment agent can be used for at least one of the following purposes: improving the dispersibility of the conductive powder in the photosensitive composition, increasing the affinity of the conductive powder with other components, or preventing surface oxidation of the metal constituting the conductive powder. Examples of the organic surface treatment agent include fatty acids such as carboxylic acids and benzotriazole compounds.

[0044] In one suitable embodiment, the conductive powder comprises metal-ceramic core-shell particles. The metal-ceramic core-shell particles have: a core portion comprising a metal material; and a covering portion comprising a ceramic material and covering at least a portion of the surface of the core portion. The covering portion is typically composed of a plurality of fine ceramic particles. The average particle size of the ceramic particles constituting the covering portion is typically smaller than the average particle size of the metal material constituting the core portion, for example, it can be about 1 / 1000 to 1 / 2, or further about 1 / 100 to 1 / 10 of the average particle size of the metal material. Ceramic materials have excellent chemical stability, heat resistance, and durability. Therefore, by adopting the morphology of metal-ceramic core-shell particles, the stability of the conductive powder in the photosensitive composition can be better improved, and a highly durable conductive layer can be achieved. In addition, for example, in the application of forming a conductive layer on a ceramic substrate to manufacture ceramic electronic components, the integrity with the ceramic substrate can be improved, and peeling and disconnection of the conductive layer after firing can be suitably suppressed.

[0045] While not particularly limited, examples of the ceramic material constituting the coating of the core-shell particles include oxide materials such as zirconia, magnesia, alumina, silica, titania, ceria, yttria, and barium titanate; composite oxide materials such as cordierite, mullite, forsterite, steatite, sialon, zircon, and ferrite; nitride materials such as silicon nitride and aluminum nitride; carbide materials such as silicon carbide; and hydroxide materials such as hydroxyapatite. For example, in applications where a conductive layer is formed on a ceramic substrate to manufacture a ceramic electronic component, a ceramic material having the same or excellent affinity as the ceramic substrate is preferred. Although not particularly limited, the content ratio of the ceramic material in the core-shell particles can be, for example, 0.01 to 5.0 parts by mass relative to 100 parts by mass of the metal material in the core portion.

[0046] There are no particular limitations. When commercially available conductive powder is used, the average particle size (nominal value) of the conductive powder can be approximately 0.1 to 10 μm for the sake of balance with exposure performance (e.g., light absorption, light curing degree). By setting the average particle size (nominal value) to the above range, fine wire wiring can be further stably formed. From the viewpoint of suppressing aggregation in the photosensitive composition and improving the storage stability of the photosensitive composition, the average particle size (nominal value, such as a value based on a laser diffraction / scattering method, SEM observation, etc.) of the conductive powder can be, for example, 0.5 μm or more, 1 μm or more, 1.5 μm or more, or 2 μm or more. In addition, from the viewpoint of improving fine wire formability, or promoting densification and low resistance of the conductive layer, the average particle size (nominal value) of the conductive powder can be, for example, 5 μm or less, 4.5 μm or less, or 4 μm or less.

[0047] Without particular limitation, the conductive powder is typically spherical with an average aspect ratio of approximately 1 to 2, preferably 1 to 1.5, for example, 1 to 1.3. This allows for more stable exposure performance. It should be noted that the "average aspect ratio" in this specification refers to the arithmetic mean of the aspect ratios (ratio of major diameter to minor diameter) calculated from an image obtained by observing a plurality of conductive particles constituting the conductive powder with an electron microscope. In addition, "spherical" in this specification refers to a shape that is considered to be roughly spherical (ball) as a whole, and may also include elliptical, polyhedral, disc-shaped, etc.

[0048] There is no particular limitation, but the conductive powder is L-based on JIS Z 8781:2013. * a * b * Luminance L in the colorimetric system * It can be 50 or more. Thus, during exposure, light stably reaches deep into the uncured conductive film, and for example, a conductive layer with a thickness of 5 μm or more, or even 10 μm or more, can be stably formed. From the above viewpoint, the brightness L of the conductive powder is * It can be approximately 55 or more, for example, 60 or more. * The measurement can be performed using a spectrophotometer in accordance with JIS Z8722:2009, for example.

[0049] In this process, the average particle size of the conductive powder used is then measured. The method for measuring the average particle size, the measuring device and the measuring conditions, as well as the analytical conditions for the measuring results, can be unified with those for calculating the first correlation equation described later. This can improve the expected accuracy in the confirmation process (step S2) of the predicted deviation width described later. In one example, a particle size distribution measurement is performed using a particle size distribution measuring device based on a laser diffraction / scattering method. For example, by using the Microtrac MT-3000II series manufactured by Microtrac BEL Co., Ltd., a particle size range of approximately 0.02 to 2800 μm can be measured. By measuring the particle size distribution, the volume-based particle size distribution of the conductive powder can be obtained. Moreover, in the particle size distribution, the particle size (D50 particle size) corresponding to 50% of the cumulative value from the side with the smallest particle size is used as the "average particle size (measured value)". As described above, the average particle size (measured value) of the conductive powder used in the manufacture of the photosensitive composition is obtained.

[0050] <(Step S2) Confirmation Step of Prediction Deviation Width>

[0051] In this step, first, a first correlation equation is prepared. For example, the first correlation equation is prepared in advance according to the type of conductive powder (for example, according to the product name). The correlation coefficient R of the first correlation equation is 2 It can be approximately 0.85 or more, preferably 0.9 or more, for example 0.92 or more. The first correlation equation can be prepared, for example, as follows.

[0052] That is, first, a plurality of conductive powders having different production batches and / or average particle sizes (nominal values) are prepared. At this time, the metal type, average aspect ratio, brightness L of the conductive powders, which may have a significant impact on the physical properties other than the particle size of the conductive powders, such as exposure performance (e.g., light absorption, light curing degree), are selected. * By making the conditions uniform (roughly the same), errors other than particle size are eliminated, allowing a clear evaluation of the influence of particle size itself. Next, the average particle size of each of the prepared conductive powders is measured individually. The average particle size can be measured using conventionally known measurement methods. For example, a particle size distribution analyzer based on the laser diffraction / scattering method can be used.

[0053] Next, photosensitive compositions are prepared using various types of conductive powders with measured average particle sizes. For example, a predetermined vehicle containing an organic component is prepared, and the conductive powder is dispersed therein to prepare the photosensitive composition. This allows the preparation of various photosensitive compositions, each containing the same components and blending ratios other than the conductive powder, differing only in the type of conductive powder. Each of these prepared photosensitive compositions is then applied to a substrate, photocured, and etched. This results in the formation of fine wires.

[0054] Next, observe the wiring on the substrate and measure the line width of the wiring from the obtained observation image. When observing the wiring, a laser microscope can be used, for example. At this time, the line width is measured for multiple fields of view, and the arithmetic mean thereof is taken as the actual line width (actual line width). Then, for example, the data is plotted in a graph of "average particle size (measured value) X-actual line width Y" where the average particle size (measured value) of the conductive powder is taken on the horizontal axis X and the actual line width is taken on the vertical axis Y. Based on the graph, calculate the correlation between the average particle size (measured value) and the actual line width. Prepare the first correlation equation in this way.

[0055] In this process, the measured value obtained in step S1 is then compared with the first correlation equation for the same type of conductive powder. Then, the deviation width (predicted deviation width) assumed relative to the predetermined target line width is confirmed. For example, first, the measured value obtained in step S1 is interpolated into the correlation equation between the average particle size (measured value) and the actual line width to calculate the expected line width. Then, the difference between the expected line width and the desired target line width is calculated as the predicted deviation width. It should be noted that the target line width can be set arbitrarily. In this way, the predicted deviation width is confirmed.

[0056] <(Step S3) Step of determining the mixing ratio of organic components>

[0057] In this step, first, a second correlation equation is prepared. For example, the second correlation equation is prepared in advance according to the type of conductive powder (for example, according to the product name). The correlation coefficient R of the second correlation equation is 2 It can be approximately 0.85 or greater, preferably 0.9 or greater, for example 0.92 or greater. The second correlation can be expressed as a linear function. In a linear function, two variables are in a proportional relationship. Therefore, the mixing ratio can be calculated simply and easily. The second correlation can be prepared, for example, as follows. That is, first, prepare at least one of the organic components used in the manufacture of the photosensitive composition. For example, prepare at least one of the organic components contained in the carrier used when calculating the first correlation. The prepared organic component can be one, or for example, two or more.

[0058] Without being particularly limited, the organic components prepared at this time may include: components that affect the curing speed of the photosensitive composition, for example, organic components other than organic binders and photocurable compounds, for adjusting at least one of the light absorptivity and photopolymerizability of the photosensitive composition (curing speed adjusters). The prepared organic components may include, for example, at least one of (A) a photopolymerization initiator, (B) a sensitizer, (C) a light absorber, and (D) a polymerization inhibitor. Among them, a polymerization initiator system, that is, at least one of (A) a photopolymerization initiator and (B) a sensitizer may be included. The prepared organic components may be, for example, the first component with the highest blending ratio in the carrier among the components (A) to (D), and may further include the second component with the second highest blending ratio.

[0059] (A) A photopolymerization initiator is a component that decomposes upon light irradiation to generate active substances such as free radicals and cations, thereby causing the polymerization reaction of the photocurable component to proceed. A photopolymerization initiator is a component that adjusts the photopolymerizability of the photosensitive composition (in detail, accelerates the polymerization reaction). As a photopolymerization initiator, one type can be used alone or two or more types can be used in combination, depending on, for example, the type of photocurable component. The photopolymerization initiator can be a photoradical polymerization initiator, a photocationic polymerization initiator, or a photoanionic polymerization initiator. From the perspective of fast reaction speed and the absence of the need for thermal curing, a photoradical polymerization initiator is particularly preferred. Typical examples include benzoin-based photopolymerization initiators, α-hydroxyacetophenone-based photopolymerization initiators, α-aminoalkylphenone-based photopolymerization initiators, benzyl ketal-based photopolymerization initiators, α-hydroxyacetophenone-based photopolymerization initiators, α-aminoacetophenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, titanocene-based photopolymerization initiators, O-acyloxime-based photopolymerization initiators, oxime ester-based photopolymerization initiators, benzophenone-based photopolymerization initiators, and acridine-based photopolymerization initiators.

[0060] (B) Sensitizer (also known as accelerator, reaction accelerator, etc.) is a component that transfers the energy obtained by absorbing light to the photocurable component, thereby promoting the polymerization reaction of the photocurable component. The sensitizer is a component that adjusts the photopolymerizability of the photosensitive composition (specifically, accelerates the polymerization reaction). As a sensitizer, one type can be used alone or two or more types can be used in appropriate combinations, depending on, for example, the wavelength of the irradiated light. Typical examples include anthracene sensitizers, aromatic ketone sensitizers, biphenyl sensitizers, anthraquinone sensitizers, etc.

[0061] (C) A light absorber (also referred to as a colorant, organic pigment, etc.) is a component that adjusts the light absorptivity of the photosensitive composition. A light absorber is typically a component that only changes the color of the photosensitive composition to adjust the transmittance of light. The light absorber can be an ultraviolet absorber that absorbs part or all of the light of the ultraviolet wavelength, an infrared absorber that absorbs part or all of the light of the infrared wavelength, or a visible light absorber (such as a black agent) that absorbs part or all of the light of the visible wavelength. As a light absorber, one type can be used alone from among those known in the past, for example, according to the wavelength range of the irradiated light, or two or more types can be used in suitable combination. Typical examples include benzotriazole-based light absorbers, triazine-based light absorbers, benzophenone-based light absorbers, benzoate-based light absorbers, salicylate-based light absorbers, cyanoacrylate-based light absorbers, resorcinol-based light absorbers, hindered amine-based light absorbers, etc.

[0062] In particular, the UV absorber has the effect of reducing the following phenomenon: during UV exposure, light penetrating from the opening of the photomask into the interior of the conductive film is scattered, causing the light-shielding portion of the photomask to solidify and the line width to become wider than the opening width of the photomask.

[0063] As ultraviolet absorbers, those having a high absorption coefficient in the wavelength range of 250 to 520 nm are preferred, and organic dyes having a high absorption coefficient in the wavelength range of 350 to 450 nm are particularly preferred. Examples of organic dyes include azo, benzophenone, aminoketone, xanthene, quinoline, aminoketone, anthraquinone, diphenylcyanoacrylate, triazine, and p-aminobenzoic acid dyes. Among them, azo and benzophenone organic dyes are preferred.

[0064] Examples of azo-based organic dyes include Sudan Blue, Sudan R, Sudan II, Sudan III, Sudan IV, Oil Orange SS, Oil Violet, and Oil Yellow OB. Examples of benzophenone-based organic dyes include Uvinul (registered trademark) D-50 (2,2',4,4'-tetrahydrooxybenzophenone), Uvinul (registered trademark) MS40 (2-hydroxy-4-methoxybenzophenone 5-sulfonic acid), and Uvinul (registered trademark) DS49 (sodium 2,2-dihydroxy-4,4'-dimethoxybenzophenone-5,5'-disulfonate) manufactured by BASF Corporation.

[0065] (D) A polymerization inhibitor (also known as an inhibitor, light stabilizer, stabilizer, free radical scavenger, oxygen scavenger, etc.) is a component that hinders the polymerization reaction of the photocurable component to improve at least one of the weather resistance, heat resistance, and storage stability of the photosensitive composition. The polymerization inhibitor is a component that adjusts the photopolymerization properties of the photosensitive composition (specifically, slows down the polymerization reaction). As a polymerization inhibitor, one type can be used alone from among the conventionally known ones, or two or more types can be used in combination. Typical examples include hydroquinone and its derivatives, and phenol derivatives.

[0066] Next, using a specified conductive powder, the mixing ratio of the prepared organic components is changed in stages to prepare a variety of photosensitive compositions. Then, in the same manner as when calculating the first correlation, the prepared photosensitive compositions are applied to the substrate, photocured and etched. Thus, fine wire wiring is formed. Next, the wiring on the substrate is observed with a laser microscope, and the line width of the wiring is measured from the obtained observation image. At this time, the line width is measured for multiple fields of view, and the arithmetic average thereof is taken as the actual line width (actual line width). Then, for example, the data is plotted on a graph of "organic component mixing ratio X-actual line width Y" with the mixing ratio of the organic components in the photosensitive composition on the horizontal axis X and the actual line width on the vertical axis Y. From this graph, the correlation between the mixing ratio of the organic components and the actual line width is calculated. In this way, the second correlation is prepared.

[0067] In this process, the second correlation is then used to determine the mixing ratio of the organic components in the photosensitive composition in a manner that eliminates the predicted deviation width confirmed in step S2. In other words, the mixing ratio of the organic components in the photosensitive composition is determined in a manner that induces the target line width. In one example, the mixing ratio of the carrier used when calculating the first correlation is set as the basis. Then, for at least one of the organic components for which the second correlation has been calculated, the mixing ratio is changed from the carrier that serves as the basis. In this way, the predicted deviation width confirmed in step S2 can be eliminated. It should be noted that the organic component whose mixing ratio has not been changed can be the same as the carrier that serves as the basis. The organic component whose mixing ratio is changed can be one kind. For example, in the case where the predicted deviation width is large, the predicted deviation width as a whole can also be eliminated by changing the mixing ratio of two or more organic components little by little.

[0068] For example, in the case of using a polymerization initiator system to eliminate the predicted deviation width, first, as the second correlation formula, a correlation formula between the mixing ratio of the polymerization initiator system and the actual line width is prepared. For example, two correlation formulas are prepared: a correlation formula between the mixing ratio of the photopolymerization initiator and the actual line width, and a correlation formula between the mixing ratio of the sensitizer and the actual line width. In this correlation formula, it is assumed that the mixing ratio of the polymerization initiator system and the actual line width have a positive correlation. In this case, if the expected line width is larger than the target line width, then based on the correlation formula, the mixing ratio of the polymerization initiator system is reduced by the mixing of the carrier that serves as the basis in such a manner as to eliminate the predicted deviation width. On the other hand, if the expected line width is smaller than the target line width, then based on the correlation formula, the mixing ratio of the polymerization initiator system is increased by the mixing of the carrier that serves as the basis in such a manner as to eliminate the predicted deviation width.

[0069] In addition, for example, when using an inhibitor to eliminate the predicted deviation width, first, as the second correlation, a correlation formula between the mixing ratio of the inhibitor and the actual line width is prepared. In this correlation formula, it is assumed that the mixing ratio of the inhibitor and the actual line width have a negative correlation. In this case, if the expected line width is larger than the target line width, the mixing ratio of the inhibitor is increased based on the correlation formula by adjusting the carrier as the basis in such a manner as to eliminate the predicted deviation width. In addition, if the expected line width is smaller than the target line width, the mixing ratio of the inhibitor is reduced based on the correlation formula by adjusting the carrier as the basis in such a manner as to eliminate the predicted deviation width. As described above, the mixing ratio of the organic components in the photosensitive composition is determined.

[0070] It should be noted that the organic components whose blending ratios are adjusted in this step are not limited to the components (A) to (D) described above. For example, the blending ratio of at least one of the photocurable resin and the photocurable compound described below may be adjusted, as long as other properties (such as the adhesion of the conductive film to the substrate) are not significantly reduced. Furthermore, for example, the blending ratios of other additional components described below may be adjusted.

[0071] <(Step S4) Photosensitive Composition Preparation Step>

[0072] In this process, a photosensitive composition is prepared using the conductive powder whose average particle size is measured in step S1. For example, first, an organic binder, a photocurable compound, a photopolymerization initiator, a sensitizer, a light absorber, an inhibitor, and other additives used as needed are mixed in an organic dispersion medium to prepare a liquid carrier. At this time, each component is added in such a way that the photosensitive composition becomes the mixing ratio determined in step S3. Next, the conductive powder and the carrier are mixed in a predetermined mixing ratio. Thus, a photosensitive composition is prepared. In this embodiment, a photosensitive composition (a paste-like photosensitive composition) that contains an organic dispersion medium and is prepared in a paste state (including a slurry state or an ink state) can be obtained.

[0073] An organic binder (polymer component) is a component that improves the adhesion between the substrate and the uncured conductive film. The organic binder may be photosensitive (referring to the property of producing chemical or structural changes by light, such as photocurability) or not. The organic binder includes: a photopolymerizable oligomer (prepolymer) with a weight average molecular weight of 2000 or more and less than 5000, and a photopolymerizable polymer with a weight average molecular weight of 5000 or more. As an organic binder, one type can be used alone or two or more types can be used in appropriate combination according to the types of substrate, photopolymerizable compound, photopolymerization initiator, etc. from conventionally known ones. As an organic binder, one that can be easily removed with a developer in the development process is preferred. For example, when an alkaline developer is used in the development process, a compound having an acidic structural portion such as a hydroxyl group (-OH), a carboxyl group (-C(=O)OH), an ester bond (-C(=O)O-), or a sulfonic group (-SO3H) is preferred. As a result, residue becomes less likely to remain in the unexposed portion, and for example, the space between the fine lines can be stably ensured.

[0074] Preferred examples of organic binders include cellulose-based polymers such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, and hydroxymethyl cellulose, acrylic resins, phenol resins, alkyd resins, polyvinyl alcohol, and polyvinyl butyral. Among these, hydrophilic organic binders such as cellulose-based polymers and acrylic resins are preferred from the perspective of ease of removal during the development step.

[0075] In addition, as an organic binder, a photocurable resin can be used. A photocurable resin is a photocurable component that is polymerized and cured by an active substance generated by a photopolymerization initiator. A photocurable resin typically has at least one of one or more unsaturated bonds and a cyclic structure. As a photocurable resin, one type can be used alone from those known in the past, or two or more types can be used in appropriate combination. As a typical example, resins having olefinic double bonds such as (meth)acryloyl, vinyl, and allyl groups, such as acrylic resins, epoxy resins, etc., can be cited. It should be noted that in this specification, "(meth)acryloyl" is a term that includes "methacryloyl" and "acryloyl".

[0076] Specific examples of acrylic resins include homopolymers of alkyl (meth)acrylates such as polymethyl (meth)acrylate, polyethyl (meth)acrylate, and polybutyl (meth)acrylate, and copolymers containing an alkyl (meth)acrylate as a main monomer (the monomer occupying the largest mass ratio) and a secondary monomer copolymerizable with the main monomer.

[0077] Photocurable compounds (monomer components) are photocurable components that are polymerized and cured by active substances generated by photopolymerization initiators. The polymerization reaction may be, for example, addition polymerization or ring-opening polymerization. Photocurable compounds may be free radical polymerizable or cationic polymerizable. Photocurable compounds are monomers having a weight-average molecular weight of less than 2000. As photocurable compounds, one type may be used alone from those known in the past, or two or more types may be used in appropriate combination. As a typical example, a (meth)acrylate monomer having a (meth)acryloyl group may be cited. (Meth)acrylate monomers include: monofunctional (meth)acrylates having one functional group per molecule, polyfunctional (meth)acrylates having two or more functional groups per molecule, and modified products thereof. Specific examples of (meth)acrylate monomers include polyfunctional (meth)acrylates, urethane-modified (meth)acrylates having urethane bonds, epoxy-modified (meth)acrylates, silicone-modified (meth)acrylates, and the like. In addition, in this specification, "(meth)acrylate" is a term including "methacrylate" and "acrylate".

[0078] The organic dispersion medium is a component that imparts appropriate viscosity and fluidity to the photosensitive composition to improve the operability of the photosensitive composition and the workability when it is formed into a conductive film. As an organic dispersion medium, one kind can be used alone from those known in the past, or two or more kinds can be used in combination. As typical examples, organic solvents such as alcohol solvents, glycol solvents, ether solvents, ester solvents, hydrocarbon solvents, and mineral spirits can be cited. Among them, from the viewpoint of improving the storage stability of the photosensitive composition and the operability when it is formed into a conductive film, an organic solvent with a boiling point of 150°C or more is preferred, and an organic solvent with a boiling point of 170°C or more is more preferred. In addition, as another suitable example, from the viewpoint of lowering the drying temperature after printing the conductive film, an organic solvent with a boiling point of 250°C or less is preferred, and an organic solvent with a boiling point of 220°C or less is more preferred.

[0079] As other additives, one kind can be used alone or two or more kinds can be used in combination. For example, antioxidants, plasticizers, surfactants, leveling agents, thickeners, wetting agents, dispersants, defoamers, antistatic agents, antigel agents, preservatives, fillers (organic fillers or inorganic fillers), glass powder, ceramic powder (Al2O3, ZrO2, SiO2, etc.), organometallic compounds (metal resinates), etc. can be mentioned.

[0080] In this embodiment, the mixing ratio of the conductive powder in the photosensitive composition is predetermined. While not particularly limited, the mixing ratio of the conductive powder can be approximately 50% by mass or greater, typically 60 to 95% by mass, for example 70 to 90% by mass. By meeting this range, a dense and highly conductive conductive layer can be formed. Furthermore, the handleability of the photosensitive composition and the workability when forming it into a conductive film can be improved.

[0081] Without particular limitation, the ratio of the polymerization initiator system in the overall photosensitive composition can be set to approximately 5% by mass or less, typically 0.01 to 1% by mass, for example, 0.02 to 0.5% by mass, 0.05 to 0.2% by mass. In addition, the ratio of the light absorber can be set to approximately 0.5% by mass or less, typically 0.1% by mass or less, for example, 0.01% by mass or less, and further 0.001% by mass or less. In addition, the ratio of the polymerization inhibitor can be set to approximately 0.5% by mass or less, typically 0.1% by mass or less, for example, 0.001% by mass or less. In addition, the ratio of the photocurable resin in the overall photosensitive composition can be set to approximately 5% by mass or less, typically 0.01 to 1% by mass, for example, 0.02 to 0.5% by mass, 0.03 to 0.2% by mass. The proportion of the photocurable compound in the overall photosensitive composition can be approximately 5% by mass or less, typically 0.01 to 1% by mass, for example, 0.02 to 0.5% by mass, or 0.03 to 0.2% by mass. Furthermore, the blending ratio of the photocurable resin to the photocurable compound can be approximately 1:10 to 10:1, for example, 1:3 to 3:1, or further 1:2 to 2:1. Furthermore, the proportion of the organic dispersion medium can be approximately 1 to 50% by mass, typically 3 to 30% by mass, for example, 5 to 20% by mass. Furthermore, the proportion of other additives can be approximately 5% by mass or less, for example, 3% by mass or less.

[0082] 《Application of photosensitive composition》

[0083] According to the photosensitive composition disclosed herein, a conductive layer having an L / S ratio of 30 μm / 30 μm and a further L / S ratio of 20 μm / 20 μm can be stably formed. Therefore, the photosensitive composition disclosed herein can be suitable for forming a conductive layer in various electronic components such as inductor components, capacitor components, and multilayer circuit substrates. The electronic component can be various mounting forms such as a surface mounting type and a through-hole mounting type. The electronic component can be a stacked type, a winding type, or a film type. Typical examples of inductor components include high-frequency filters, common-mode filters, inductors (coils) for high-frequency circuits, inductors (coils) for ordinary circuits, high-frequency filters, choking coils, transformers, etc.

[0084] In addition, the photosensitive composition in which the conductive powder contains metal-ceramic core-shell particles can be suitable for forming a conductive layer of ceramic electronic components. It should be noted that in this specification, "ceramic electronic components" include all electronic components having an amorphous ceramic substrate (glass ceramic substrate) or a crystalline (i.e., non-glass) ceramic substrate. As typical examples, high-frequency filters, ceramic inductors (coils), ceramic capacitors, low-temperature co-fired ceramic substrates (LTCC substrates), high-temperature co-fired ceramic substrates (HTCC substrates), etc. having a ceramic substrate can be cited.

[0085] Figure 3 1 is a cross-sectional view schematically showing the structure of the stacked chip inductor 10. It should be noted that, Figure 3 The dimensional relationships (length, width, thickness, etc.) in the drawings do not necessarily reflect the actual dimensional relationships. In addition, the symbols X and Y in the drawings represent the left-right direction and the up-down direction, respectively. However, these are directions for the convenience of explanation only.

[0086] The stacked chip inductor 10 includes a main body 11 and external electrodes 20 provided on both side surfaces of the main body 11 in the left-right direction X. The shape of the stacked chip inductor 10 is, for example, a 1608 shape (1.6 mm × 0.8 mm), a 2520 shape (2.5 mm × 2.0 mm), or other sizes. The main body 11 has a structure in which a ceramic layer (dielectric layer) 12 and an internal electrode layer 14 are integrated. The ceramic layer 12 is made of the above-mentioned ceramic material as a covering portion that can constitute a conductive powder. In the vertical direction Y, the internal electrode layer 14 is arranged between the ceramic layers 12. The internal electrode layer 14 is formed using the above-mentioned photosensitive composition. The internal electrode layers 14 adjacent to each other in the vertical direction Y with the ceramic layer 12 sandwiched therebetween are connected by through holes 16 provided in the ceramic layer 12. As a result, the internal electrode layer 14 is configured into a three-dimensional spiral shape (spiral shape). Both ends of the internal electrode layer 14 are connected to the external electrodes 20, respectively.

[0087] The stacked chip inductor 10 can be manufactured, for example, according to the following steps. That is, first, a paste containing a ceramic material, a binder resin and an organic solvent as raw materials is prepared, and the paste is supplied to a carrier to form a ceramic green sheet. Then, the ceramic green sheet is rolled and cut into the desired size to obtain a plurality of green sheets for forming ceramic layers. Then, a puncher or the like is used to form conductive holes at specified positions of the plurality of green sheets for forming ceramic layers. Then, a conductive film having a specified coil pattern is formed at specified positions of the plurality of green sheets for forming ceramic layers using the above-mentioned photosensitive composition. As an example, a conductive film in an unfired state can be formed by a manufacturing method comprising the following steps: (Step A) a step of applying a photosensitive composition to a green sheet for forming a ceramic layer and drying it to form a conductive film of a dried body containing the photosensitive composition; (Step B) a step of covering the conductive film with a photomask having a specified opening pattern, exposing the conductive film through the photomask, and partially photocuring the conductive film; (Step C) a step of etching the photocured conductive film to remove the uncured portion.

[0088] It should be noted that when the conductive film is formed using the above-mentioned photosensitive composition, conventionally known techniques can be appropriately used. For example, in (step A), the application of the photosensitive composition can be carried out by various printing methods such as screen printing, a bar coater, etc. The drying of the photosensitive composition can typically be carried out at 50 to 100°C. In (step B), an exposure machine that emits radiation such as visible light, ultraviolet light, X-rays, electron beams, α-rays, β-rays, and γ-rays can be used for exposure. As an example, an exposure machine that emits light in a wavelength range of 10 to 400 nm, such as a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, or other ultraviolet irradiation lamp can be used. In (step C), an aqueous solution containing an alkali component such as sodium hydroxide or sodium carbonate can be used for etching.

[0089] Next, a plurality of green sheets for forming a ceramic layer that forms an unfired conductive film are stacked and pressed together. Thus, a stack of unfired ceramic green sheets is produced. Next, the stack of ceramic green sheets is fired at, for example, 600 to 1000°C. Thus, the ceramic green sheets are sintered as a whole to form a main body 11, which includes: a ceramic layer 12, and an internal electrode layer 14 of a fired body containing a photosensitive composition. Furthermore, an appropriate external electrode forming paste is applied to both ends of the main body 11 and fired to form external electrodes 20. In this way, a stacked chip inductor 10 can be manufactured.

[0090] 《Mixture ratio determination device》

[0091] Figure 4 This is a functional block diagram of the mixing ratio determination device 30. The mixing ratio determination device 30 disclosed herein includes an input unit 31, a storage unit 32, a first calculation unit 33, a second calculation unit 34, and a display unit 35. The various components of the mixing ratio determination device 30 are configured to communicate with each other. The various components of the mixing ratio determination device 30 may be implemented by software or hardware. The various components of the mixing ratio determination device 30 may be implemented by a processor or incorporated into a circuit.

[0092] The input unit 31 is configured to accept operation input from a user (e.g., an operator who prepares a photosensitive composition) and input the type of conductive powder used, the average particle size (measured value), and the target line width. When a plurality of conductive powders are used in combination, the input unit 31 is configured to further input their mixing ratio. The type of conductive powder is, for example, information represented by the place of purchase, variety name (product name), product number, etc. The type of conductive powder can be, for example, the structure of the conductive powder (whether it is a core-shell structure), average particle size (nominal value), average aspect ratio, brightness L * The input unit 31 includes, for example, a keyboard with cursor keys, numeric input keys, a pointing device such as a mouse, and an input device such as buttons (not shown). The input unit 31 can be configured to select the type of conductive powder from a drop-down menu displayed on the display unit 35. The input unit 31 can be configured to obtain the above information from an external device such as a computer or a network connected by wire or wireless. It should be noted that in this embodiment, the "target line width" is an example of a pre-defined target level.

[0093] The storage unit 32 stores the first correlation equation and the second correlation equation. The first correlation equation and the second correlation equation are pre-stored in the storage unit 32 according to the type of conductive powder (for example, according to the product name). Therefore, the first correlation equation and the second correlation equation stored in the storage unit 32 are typically multiple. The first correlation equation can be represented by a linear function. Without special limitation, the first correlation equation is, for example, a correlation equation between the average particle size (measured value) of the above-mentioned conductive powder and the actual line width. The second correlation equation has a specified slope (ratio of change). The second correlation equation can be represented by a linear function. Without special limitation, the second correlation equation is, for example, a correlation equation between the mixing ratio of the above-mentioned organic components (for example, a polymerization initiator system) and the actual line width. The storage unit 32 can further store the composition of the carrier serving as the basis, that is, the type and mixing ratio of each organic component contained in the carrier.

[0094] If the user inputs the type of conductive powder and the average particle size (measured value) to be used from the input unit 31, the first calculation unit 33 refers to the first correlation equation of the conductive powder of the same type as the input conductive powder from the first correlation equation stored in the storage unit 32. Then, the predicted deviation width relative to the target line width is calculated from the average particle size (measured value) input from the input unit 31. For example, when the first correlation equation is expressed as a correlation equation between the average particle size (measured value) of the conductive powder and the actual line width, first, the average particle size (measured value) input from the input unit 31 is interpolated into the corresponding first correlation equation to calculate the expected line width. Then, the difference between the expected line width and the target line width input by the user from the input unit 31 is calculated as the predicted deviation width. It should be noted that in this embodiment, the "predicted deviation width" is an example of a predicted deviation value.

[0095] Once the predicted deviation width is calculated by the first calculation unit 33, the second calculation unit 34 references the second correlation equation for the same type of conductive powder as the input conductive powder from the second correlation equation stored in the storage unit 32. The organic component blending ratio is then calculated based on the predicted deviation width calculated by the first calculation unit 33. For example, if the second correlation equation represents the correlation between the blending ratio of the polymerization initiator system and the actual line width, the predicted deviation width is divided by the slope of the second correlation equation to calculate the blending ratio of the polymerization initiator system required to eliminate the predicted deviation width. The blending ratio required to eliminate the predicted deviation width is then adjusted based on the blending ratio of the photopolymerization initiator contained in the carrier to obtain the final blending ratio.

[0096] The mixing ratio determination device 30 is, for example, a computer and includes an interface (I / F) for the user, a central processing unit (CPU) that executes commands of a control program, a ROM (read-only memory) that stores programs executed by the CPU, a RAM (random access memory) used as a work area for developing the programs, and a storage device such as a memory that stores the programs and various data. The mixing ratio determination device 30 may be a computer program configured to cause the computer's CPU to operate as each component of the mixing ratio determination device 30. The computer program may be a recording medium in which the operation of the mixing ratio determination device 30 is written and which is readable by the computer.

[0097] Examples of recording media include semiconductor recording media (e.g., ROM, non-volatile memory cards), optical recording media (e.g., digital video discs (DVDs), magneto-optical discs (MOs), mini discs (MDs), compact discs (CDs), and Blu-ray discs (BDs)), and magnetic recording media (e.g., magnetic tapes and floppy disks). Furthermore, the computer program can be transmitted to a server computer via the recording media or a network such as the Internet or an intranet. In this case, the server computer also constitutes one embodiment of the compounding ratio determination device 30.

[0098] Several embodiments of the present invention will be described below, but the present invention is not intended to be limited to the embodiments.

[0099] <Example 1: Case of using only one type of conductive powder>

[0100] Hereinafter, the case of producing a photosensitive composition using only one type of conductive powder will be described. Here, as a preliminary preparation, first, a first correlation equation and a second correlation equation corresponding to the conductive powder used are prepared. Specifically, Figure 5 The first correlation shown is Figure 6 The second correlation of . Figure 6 This is the second correlation equation for adjusting the mixing ratio of photopolymerization initiators.

[0101] Figure 5The first correlation equation shown is prepared as follows. That is, first, as conductive powder, a plurality of (here 15 kinds) commercially available silver powders having an average particle size (nominal value) of approximately 3 μm are prepared. Next, using a particle size distribution measuring device based on a laser diffraction / scattering method (Model "MT-3000II" manufactured by Microtrac BEL Co., Ltd., measurement range: 0.02 to 2800 μm), the average particle sizes of the 15 kinds of silver powders are measured by wet measurement in a dispersion solvent. As a dispersion solvent, an alcohol solvent (specifically ethanol) is used from the viewpoint of suppressing the aggregation of the silver powder and dispersing each particle in the dispersion solvent. Then, a volume-based particle size distribution is obtained. It should be noted that the particle size distribution is typically unimodal with only one mode diameter (modal particle size). The average particle sizes (measured values) of the 15 kinds of silver powders are read from the particle size distribution.

[0102] Next, an organic binder, a photocurable compound, a photopolymerization initiator, a sensitizer, a UV absorber as a light absorber, and a polymerization inhibitor were dissolved in an organic dispersion medium according to the composition shown in Table 1 to prepare a vehicle. Subsequently, the 15 types of silver powder prepared above were mixed with the vehicle at a mass ratio of 77:23 to prepare photosensitive compositions.

[0103] [Table 1]

[0104] Table 1 Composition of carrier

[0105]

[0106] Next, the prepared photosensitive composition is applied to commercially available ceramic green sheets by screen printing. Then, it is dried at 60°C for 15 minutes and formed into a conductive film (whole-surface film) on the green sheet (conductive film forming process). Next, a photomask is applied over the conductive film. As a photomask, a photomask with L / S = 25μm / 25μm is used. With the photomask covering the conductive film, an ultraviolet exposure machine is used at 2500mJ / cm 2 The conductive film is partially cured by irradiating the ceramic green sheet with light of a certain intensity (exposure step). After exposure, a 0.4 mass% Na2CO3 aqueous solution is blown onto the ceramic green sheet to etch away the uncured conductive film. The sheet is then rinsed with pure water and dried at room temperature (development step). In this way, a wiring pattern is formed on the ceramic green sheet.

[0107] Next, the wiring pattern is observed with a laser microscope, and the line width of the wiring is measured from the obtained observation image. It should be noted that the line width is measured for multiple fields of view, and the arithmetic average thereof is taken as the actual line width (actual line width). Figure 5As shown in FIG. 1 , the correlation between the average particle size (measured value) of 15 types of silver powder and the actual line width is shown in a graph, and a correlation formula (Y=5.593X+11.192) is calculated. Figure 5 In the first correlation formula shown, the average particle size (measured value) of the silver powder is proportional to the actual line width formed using the photosensitive composition containing the silver powder (correlation coefficient: 0.92). Figure 5 The first correlation equation shown is expressed as a linear function. Figure 5 In the graph, the average particle size (measured value) and the actual line width have a positive correlation. That is, as the average particle size (measured value) of the silver powder increases, the line width increases linearly.

[0108] Figure 6 The second correlation equation is prepared as follows. First, a predetermined silver powder is prepared as a conductive powder. Separately, an organic binder, a photocurable compound, a photopolymerization initiator, a sensitizer, a UV absorber, a polymerization inhibitor, and an organic dispersion medium are mixed in the ratios shown in Table 1 to prepare a base vehicle. Next, the silver powder and the vehicle are mixed in a mass ratio of 77:23 to prepare a base photosensitive composition.

[0109] Next, the mixing ratio of the photopolymerization initiators (photopolymerization initiator and sensitizer) in the base photosensitive composition was changed as shown in Table 2. The amount of organic dispersion medium was increased or decreased to adjust the amount of the photopolymerization initiator. For example, if the mixing ratio of the photopolymerization initiator was reduced from 0.550 to 0.515, the amount of organic dispersion medium was increased by that amount (0.035). Multiple (here, five patterns) of these photosensitive compositions were prepared. It should be noted that when the mixing ratio of the photopolymerization initiator was changed, the ratio of the photopolymerization initiator to the sensitizer was kept constant. Next, using the multiple photosensitive compositions prepared above, wiring patterns were formed in the same manner as when calculating the first correlation equation, and the actual line width was determined. The correlation between the mixing ratio of the photopolymerization initiator in the five patterns and the actual line width was then plotted in a graph, and the correlation equation (Y = 74.927X + 19.762) was calculated.

[0110] [Table 2]

[0111] Table 2 Compounding ratio of photopolymerization initiators

[0112] Compounding ratio in carrier (mass %) 0.621 0.585 0.550 0.515 0.479 Compounding ratio in the photosensitive composition (mass %) 0.143 0.135 0.127 0.118 0.110 Actual line width (μm) 30.5 29.7 29.5 28.4 28.1

[0113] Figure 6 In the second correlation formula, the mixing ratio of the polymerization initiator system in the photosensitive composition is proportional to the actual line width (correlation coefficient: 0.96). Figure 6 The second correlation is expressed as a linear function. Figure 6In the graph, the mixing ratio of the polymerization initiator system has a positive correlation with the actual line width. That is, it can be seen that as the mixing ratio of the polymerization initiator system increases, the line width becomes linearly thicker.

[0114] In Example 1, after aligning the first and second correlations as described above, silver powder (average particle size (nominal value): 3 μm) was prepared for use in the photosensitive composition as step S1. Next, the average particle size of the silver powder was measured using the same particle size distribution measuring instrument used to calculate the first correlation, under the same measurement and analysis conditions. The average particle size (measured value) of the silver powder was then read from the volume-based particle size distribution. Here, the measured value was 3.17 μm.

[0115] Next, as step S2, the measured value obtained in step S1 is compared with Figure 5 Then, the predicted deviation width relative to the pre-specified target line width is confirmed. Here, if the measured value of 3.17μm is interpolated to Figure 5 Using the first correlation (Y = 5.593X + 11.192), the expected line width is calculated to be 28.92 μm. Therefore, if the target line width is 27.3 μm, the predicted deviation width is calculated as (expected line width 28.92 μm) - (target line width 27.3 μm) to be +1.62 μm. This indicates that if a photosensitive composition is prepared directly using the basic vehicle composition, there is a high probability that a line width greater than the target line width of 1.62 μm will be produced.

[0116] Therefore, next, as step S3, the mixing ratio of the organic component is changed so as to eliminate the predicted deviation width and approach the target line width. Figure 6 The second correlation equation (Y = 74.927X + 19.762) was used to adjust the polymerization initiator ratio. Specifically, the value obtained by dividing the predicted deviation width + 1.62 μm by the slope of the second correlation equation, 74.927 (= 1.62 / 74.927) = +0.022 is the amount of polymerization initiator required to adjust the predicted deviation width + 1.62 μm. Therefore, to eliminate the predicted deviation width, the polymerization initiator ratio was reduced by 0.022% by mass from the base photosensitive composition. Table 3 shows an example of the polymerization initiator ratio determined in consideration of the predicted deviation width.

[0117] [Table 3]

[0118] Table 3 Compounding ratio of photopolymerization initiators

[0119]

[0120] ※A plus sign (+) indicates a thicker line relative to the target line width.

[0121] Next, as step S4, as shown in Table 3, a carrier with a changed mixing ratio of the polymerization initiator system is prepared. It should be noted that the organic components not described in Table 3, such as organic binders, photocurable compounds, ultraviolet absorbers, and polymerization inhibitors, are the same as those in the photosensitive composition that serves as the basis. Next, the silver powder with the average particle size measured in step S1 is mixed with the carrier to prepare a photosensitive composition. Then, a wiring pattern is formed and the actual line width is measured. As a result, the actual line width is 27.4μm. That is, the result is much closer to the target line width (27.3μm) than the line width (29.0μm) expected in step S2.

[0122] Furthermore, for a variety of conductive powders, the technology disclosed herein is applied in the same manner as described above, a photosensitive composition is prepared, and the actual line width is measured. That is, in step S1, the measured value of the average particle size of the silver powder is obtained, in step S2, the predicted deviation width is confirmed, in step S3, the mixing ratio of the polymerization initiator system is determined, and after adjusting the mixing of the carrier, a photosensitive composition is prepared and the actual line width is measured. The results are shown in Table 4. It should be noted that the right end of Table 4 is the result of Example 1 above. In addition, as a reference example, the technology disclosed herein is not applied, and the actual line width (μm) when the basic carrier is directly used (that is, the mixing ratio of the polymerization initiator system is kept constant without adjustment) is recorded in the bottom section.

[0123] [Table 4]

[0124] Table 4 Compounding ratio of polymerization initiators

[0125]

[0126] ※1: A plus sign (+) indicates a thicker line width relative to the target, and a minus sign (-) indicates a thinner line width relative to the target.

[0127] ※2: A plus sign (+) indicates a decrease in the mixing ratio, and a minus sign (-) indicates an increase in the mixing ratio.

[0128] Figure 7 This is a graph summarizing the results of Table 4 and comparing the actual line widths with and without the application of the technology disclosed herein. Figure 7 Table 4 demonstrates that by applying the disclosed technology, variations between conductive powder production batches are relatively mitigated, suppressing line width fluctuations compared to a case where the disclosed technology is not applied (reference example). Line width fluctuations can be suppressed to less than ±1 μm, and further to less than ±0.5 μm. In other words, thin wiring can be stably formed near the target line width. These results demonstrate the significance of the disclosed technology.

[0129] <Example 2: When two types of conductive powders are mixed and used>

[0130] Hereinafter, the case of manufacturing a photosensitive composition using a mixed powder containing two kinds of conductive powders will be described. Here, as a preliminary preparation, first, two first correlation equations corresponding to the two kinds of conductive powders used are prepared. Specifically, Figure 8 、 9 The first correlation equation is shown by the solid line. In addition, the second correlation equation is also prepared. It should be noted that the second correlation equation is prepared in the same manner as Figure 6 The correlations shown are the same.

[0131] Figure 8 The first correlation equation represented by the solid line in the figure is prepared as follows. First, as the first conductive powder, a plurality of (seven in this case) first silver powders having an average particle size (nominal value) of approximately 2.9 μm are prepared. Then, the first silver powder is calculated based on the first embodiment. Figure 5 Similarly, when calculating the first correlation formula of , the average particle size (measured value) of each of the seven types of first silver powder was measured. In addition, as the second conductive powder, a second silver powder having an average particle size (measured value) of 2.56 μm was prepared. Next, the first silver powder and the second silver powder were mixed at a predetermined mass ratio (here, 40:60) to adjust the mixed powder. This mixed powder was mixed with the carrier shown in Table 1 at a mass ratio of 77:23 to prepare a photosensitive composition. Next, using this photosensitive composition, a wiring pattern was formed in the same manner as in Example 1 above, and the correlation formula between the average particle size (measured value) and the actual line width was calculated (Y = 1.89X + 24.85).

[0132] Figure 9 The first correlation equation represented by the solid line in the figure is prepared as follows. First, as the second conductive powder, a plurality of (here, 5) second silver powders having an average particle size (nominal value) of approximately 2.4 μm are prepared. Then, the first correlation equation is calculated based on the first embodiment. Figure 5 Similarly, when using the first correlation formula of , the average particle size (measured value) of each of the five second silver powders was measured. In addition, as the first conductive powder, a first silver powder with an average particle size (measured value) of 3.06 μm was prepared. Next, the first silver powder and the second silver powder were mixed at a mass ratio of 40:60 to adjust the mixed powder. Then, the above-mentioned Figure 8 Similarly, when calculating the first correlation equation of , the correlation equation between the average particle size (measured value) and the actual line width is calculated (Y=2.12X+24.72).

[0133] Figure 8 、 9 The first correlation equation represented by the solid line is the same as that of Example 1. Figure 5 Similarly to the first correlation equation of , the average particle size (measured value) of the silver powder after the change is proportional to the actual line width (correlation coefficient: 0.92 or more). Figure 8 、 9The first correlation equation represented by the solid line is represented by a linear function. Figure 8 、 9 The average particle size (measured value) has a positive correlation with the actual line width.

[0134] In Example 2, after aligning the two first correlation equations as above, two types of conductive powders, a first silver powder (average particle size (nominal value): 2.9 μm) and a second silver powder (average particle size (nominal value): 2.4 μm), used in the photosensitive composition, were prepared as step S1. Figure 8 、 9 Similarly, the average particle size of the first silver powder and the second silver powder is measured. Next, as step S2, the measured value of the first silver powder obtained in step S1 is compared with Figure 8 In addition, the measured value of the second silver powder is compared with the first correlation formula (Y = 1.89X + 24.85). Figure 9 Next, the predicted deviation widths α1 and α2 relative to the target line width (here, set at 30.0 μm) were calculated for each of the two silver powders. Specifically, if the measured values ​​of the first and second silver powders are x1 and x2, and the predicted line widths are y1 and y2, the predicted deviation widths α1 and α2 are calculated using the following equations.

[0135] α1=y1-30.0=1.89×x1+24.85-30.0

[0136] α2=y2-30.0=2.12×x2+24.72-30.0

[0137] Then, the predicted deviation width β (μm) when two types of conductive powders are mixed and used is calculated by the following formula using the predicted deviation widths α1 and α2.

[0138] β=α1+α2

[0139] Next, as step S3, similarly to Example 1, the mixing ratio of the polymerization initiator system contained in the vehicle was adjusted as shown in Tables 5 and 6. Next, as step S4, a photosensitive composition was prepared similarly to Example 1. A wiring pattern was then formed, and the actual line width was measured.

[0140] [Table 5]

[0141] Table 5 Compounding ratio of photopolymerization initiators

[0142]

[0143] ※1: A plus sign (+) indicates a thicker line width relative to the target, and a minus sign (-) indicates a thinner line width relative to the target.

[0144] ※2: A plus sign (+) indicates a decrease in the mixing ratio, and a minus sign (-) indicates an increase in the mixing ratio.

[0145] [Table 6]

[0146] Table 6 Compounding ratio of photopolymerization initiators

[0147]

[0148] ※1:A plus sign (+) indicates a thicker line width relative to the target line width, and a minus sign (-) indicates a thinner line width relative to the target line width.

[0149] ※2: A plus sign (+) indicates a decrease in the mixing ratio, and a minus sign (-) indicates an increase in the mixing ratio.

[0150] Tables 5 and 6 demonstrate that by applying the disclosed technology, even when two types of conductive powder are mixed, variations between production batches of the conductive powder can be mitigated, suppressing line width fluctuations. The line width fluctuation can be suppressed to less than ±1 μm, and further to less than ±0.5 μm.

[0151] It should be noted that Figure 8 、 9 The first correlation, represented by the dashed line, is for a mixture of the first and second silver powders at a mass ratio of 70:30. Even when the mixing ratio is varied, the average particle size (measured value) of the silver powder after the change is proportional to the actual line width in a linear function (correlation coefficient: 0.95 or greater), as in the first correlation represented by the solid line. The average particle size (measured value) and the actual line width have a positive correlation. This suggests that the disclosed technology can be applied to various mixed powders regardless of the mixing ratio.

[0152] The above describes suitable embodiments of the present invention. However, the above embodiments are merely examples, and the present invention can be implemented in various other forms. The present invention can be implemented based on the contents disclosed in this specification and the technical common sense in this field. The technology described in the claims includes various modifications and changes to the above-mentioned embodiments. For example, part of the above embodiments can be combined or replaced with other modifications. In addition, if the technical features do not need to be described, they can be deleted as appropriate.

[0153] In the above embodiment, the target level factor is defined by "line width", but it is not limited to this. The target level factor can be caused by the light absorption degree and light curing degree of the conductive film, for example, the thickness of the conductive film, the electrode cross-sectional area, the curing shrinkage, the resistance value, etc. Figure 1As shown in (A) and (B), light scattering changes depending on the particle size of the conductive powder. This results in changes in the light absorptivity of the conductive film, and thus in the degree of photocuring. From this perspective, it is obvious to those skilled in the art that differences in the particle size of the conductive powder not only change the aforementioned line width, but also the film thickness, cross-sectional area, and cure shrinkage. Furthermore, it is obvious to those skilled in the art that this also causes a similar change in resistance.

[0154] This point can be confirmed, for example, by the following references 1 to 3:

[0155] Reference 1: Takashi Ukaji, Plastic Surface Treatment Technology and Materials, CMC Technical Library, 206, p. 67, Correlation graph between light transmittance (%) and particle size (μm) of the coating film;

[0156] Reference 2: Yamamoto Kikinzoku Jikin Co., Ltd., Polymer Technology Report, Vol. 5 (2011), p. 20, Figure 15 (Relationship between the reaction rate and curing time of hexanediol diacrylate when the intensity of irradiation light is changed);

[0157] Reference 3: Information Technology Association, UV Curing Resin Formulation Design, Property Evaluation, and New Applications, p. 470, Figure 16 (Changes in Film Thickness During Curing Shrinkage of UV Resists).

[0158] If the records in the above-mentioned documents are taken into consideration, it is inferred that, for example, within the range of 0.1 to 10 μm, as the particle size of the conductive powder changes, the factors indicating light absorbance and light curing degree monotonically increase or decrease. In other words, it is believed that the change in line width with the displacement of the particle size is proportional to these displacements, or becomes a highly correlated shift with a constant function. From the above, it can be said that buffering the fluctuation of the line width is the same as suppressing the fluctuation of the factors involving light absorbance and light curing degree. In other words, it is believed that in the technology disclosed herein, the "target level" can be set as the target line width, can be set as the target film thickness, can be set as the target cross-sectional area, can be set as the target curing shrinkage rate, can be set as the target resistance value. In addition, it is believed that the "predicted deviation value" can be set as the deviation width, can be set as the deviation thickness, can be set as the deviation cross-sectional area, can be set as the deviation curing shrinkage rate, can be set as the deviation resistance value corresponding to the target level.

[0159] In the above embodiment, step S3 is performed after step S2, but this is not limiting. For example, after step S2, a determination step may be included in which the predicted deviation width is compared with a pre-set threshold. Furthermore, if the determination step determines that the predicted deviation width is less than the threshold, step S3 may be omitted and step S4 may be performed instead.

[0160] It should be noted that, in the above embodiment, the correlation between the average particle size (measured value) and the actual line width is exemplified as the first correlation, but is not limited to this. As a variable compared with the average particle size (measured value), for example, it can be set to the predicted deviation width obtained by subtracting the target line width from the actual line width. That is, the first correlation can be expressed as a correlation between the average particle size (measured value) and the predicted deviation width. In this case, the measured value obtained in step S1 can be interpolated into the correlation to directly confirm the predicted deviation width.

[0161] It should be noted that in the above embodiment, the correlation between the blending ratio of the organic components in the photosensitive composition and the actual line width is exemplified as the second correlation, but this is not limiting. As in the case of the first correlation, the variable to be compared with the blending ratio of the organic components can be, for example, the predicted deviation width. Furthermore, the blending ratio of the organic components can be represented, for example, by the blending ratio in the carrier, rather than the blending ratio in the photosensitive composition.

[0162] In the above embodiment, the mixing ratio determination device 30 includes an input unit 31, a storage unit 32, a first calculation unit 33, and a second calculation unit 34, but the present invention is not limited thereto. In addition to the above components, the mixing ratio determination device 30 may further include at least one of the following: a first setting unit that sets a first correlation equation for a predetermined type of conductive powder and stores it in the storage unit 32; a second setting unit that sets a second correlation equation for a predetermined type of conductive powder and stores it in the storage unit 32; and a notification unit that notifies the user of an error if the first or second correlation equation for the same type of conductive powder as the input is not stored in the storage unit 32.

[0163] While silver powder was used as the conductive powder in Examples 1 and 2 above, this is not a limitation. The mechanism by which the use of conductive powder with a large average particle size tends to diffuse the irradiated light horizontally across the conductive film during the exposure process, resulting in a larger wiring width, also applies to other metals. The technology disclosed herein can be applied not only to silver powder but also to powders containing various other metals, such as copper, platinum, palladium, aluminum, and nickel.

[0164] In the above-mentioned Examples 1 and 2, in step S1, the average particle size (D50 particle size) of the conductive powder is measured, specifically, the particle size corresponding to 50% of the cumulative value from the smaller particle size side in the volume-based particle size distribution, but it is not limited to this. In step S1, a number-based particle size distribution, etc. can also be used instead of the volume-based particle size distribution. In addition, the particle size factor, for example, can also be D40 particle size (particle size corresponding to 40% of the cumulative value from the smaller particle size side in the particle size distribution), D60 particle size (particle size corresponding to 60% of the cumulative value from the smaller particle size side in the particle size distribution), etc. instead of the average particle size (D50 particle size). In this case, the first correlation equation can be expressed as "D40 particle size (measured value) X - actual line width Y", "D60 particle size (measured value) X - actual line width Y", etc. Furthermore, for example, when the particle size distribution of the conductive powder is unimodal, the particle size factor may be a particle size that further deviates from the average particle size, such as the D5 particle size (the particle size equivalent to 5% of the cumulative value from the smaller particle size side in the particle size distribution), the D90 particle size (the particle size equivalent to 90% of the cumulative value from the smaller particle size side in the particle size distribution), the D95 particle size (the particle size equivalent to 95% of the cumulative value from the smaller particle size side in the particle size distribution), etc.

[0165] In the above-mentioned Examples 1 and 2, in step S3, a second correlation equation of the polymerization initiator system is prepared and the mixing ratio of the photopolymerization initiators is adjusted to suppress line width fluctuations, but the present invention is not limited thereto. The organic component whose mixing ratio is adjusted may be, for example, either a photopolymerization initiator or a sensitizer.

[0166] In the above-mentioned embodiments 1 and 2, in step S3, the second correlation formula of the polymerization initiator system is prepared. However, instead of or in addition to this, for example, the second correlation formula of the light absorber is prepared (see Figure 10 ), adjusting the mixing ratio of the light absorber can also suppress the fluctuation of the line width. Figure 10 In the second correlation equation shown, the mixing ratio of the ultraviolet absorber in the photosensitive composition and the actual line width are expressed as a logarithmic curve. The logarithmic curve changes rapidly, so, for example, when the predicted deviation width is large, there is an advantage that only a slight change in the mixing ratio is required. In addition, for example, the second correlation equation for the polymerization inhibitor is prepared (see Figure 11 ), adjusting the mixing ratio of the polymerization inhibitor can also suppress the fluctuation of the line width. Figure 11 In the second correlation formula shown, the compounding ratio of the photopolymerization inhibitor in the photosensitive composition is proportional to the actual line width (correlation coefficient: 0.99). Figure 11 The second correlation equation shown is expressed as a linear function. The mixing ratio of the polymerization inhibitor has a negative correlation with the actual line width. That is, it can be seen that as the mixing ratio of the polymerization inhibitor system increases, the line width becomes linearly thinner. This second correlation equation is also consistent with the above Figure 6 、 7 The second correlation equation of can also be suitably used in the technology disclosed herein.

[0167] Description of Reference Numerals

[0168] 10-layer chip inductor

[0169] 11 Main body

[0170] 12 Ceramic layer

[0171] 14 Internal electrode layer

[0172] 20 External electrodes

[0173] 30 Mixing ratio determination device

[0174] 31 Input section

[0175] 32 Storage

[0176] 33 1st Calculation Department

[0177] 34 2nd Calculation Department

[0178] 35 Display

Claims

1. A method for producing a photosensitive composition, comprising producing a photosensitive composition comprising a conductive powder in a predetermined blending ratio. The manufacturing method comprises the following steps: The process of measuring the particle size of the conductive powder used and obtaining the actual measured value; a step of comparing the measured value with a first correlation equation prepared in advance, i.e., a first correlation equation for the particle size of the conductive powder and an arbitrary factor that varies due to light absorption or photocuring of the conductive film and varies in correlation with a displacement of the particle size, to confirm a predicted deviation value of the factor from a predetermined target level; The step of determining the blending ratio of the organic component so as to eliminate the prediction deviation value based on a pre-prepared second correlation equation, that is, a second correlation equation for a factor in the first correlation equation and an arbitrary organic component contained in the photosensitive composition and in which a change in the blending ratio is correlated with a change in the factor; The factors in the first correlation equation are the line width, film thickness, electrode cross-sectional area, curing shrinkage, or resistance value of the conductive film. The correlation coefficient R of the first correlation formula 2 is 0.85 or above, The correlation coefficient R of the second correlation formula 2 It is above 0.

85.

2. The method for producing a photosensitive composition according to claim 1, wherein The organic component is an organic component that adjusts at least one of the light absorptivity and the photopolymerization property of the photosensitive composition.

3. The method for producing a photosensitive composition according to claim 1, wherein The organic component is at least one of a photopolymerization initiator, a light absorber, and a polymerization inhibitor.

4. The method for producing a photosensitive composition according to claim 1, wherein The organic component is a photopolymerization initiator.

5. The method for producing a photosensitive composition according to any one of claims 1 to 4, wherein The factor in the first correlation equation is the line width.

6. The method for producing a photosensitive composition according to any one of claims 1 to 4, wherein: The second correlation equation is expressed as a linear function.

7. The method for producing a photosensitive composition according to any one of claims 1 to 4, wherein: The conductive powder includes silver-based particles.

8. The method for producing a photosensitive composition according to any one of claims 1 to 4, wherein The conductive powder includes core-shell particles. The core-shell particles include a metal material serving as a core and a ceramic material covering at least a portion of a surface of the core.

9. The method for producing a photosensitive composition according to any one of claims 1 to 4, wherein The photosensitive composition is used for forming an electrode.

10. A method for manufacturing an electronic component, further comprising the following steps: The photosensitive composition obtained by the production method according to any one of claims 1 to 9 is applied to a substrate, photocured and etched, and then baked to form a conductive layer comprising a baked body of the photosensitive composition.

11. A mixing ratio determining device for determining a mixing ratio of an organic component to a photosensitive composition containing a conductive powder at a predetermined mixing ratio. The mixing ratio determining device comprises: An input unit that receives input from a user, inputting the type of conductive powder used and the measured value of the particle size; a storage unit storing a pre-prepared first correlation equation, i.e., a first correlation equation in which the particle size of the conductive powder varies due to light absorption or photocuring of the conductive film and varies in correlation with a displacement of the particle size; and a pre-prepared second correlation equation, i.e., a second correlation equation in which the factor in the first correlation equation and an arbitrary organic component contained in the photosensitive composition and in which a variation in the blending ratio is correlated with a variation in the factor; a first calculation unit that calculates, based on the first correlation equation, a predicted deviation value of a factor in the first correlation equation from a predetermined target level from the actual measurement value inputted from the input unit; and a second calculation unit that calculates, based on the second correlation equation, a compounding ratio of the organic component in the second correlation equation that eliminates the predicted deviation value; The factors in the first correlation equation are the line width, film thickness, electrode cross-sectional area, curing shrinkage, or resistance value of the conductive film. The correlation coefficient R of the first correlation formula 2 is greater than 0.85, and the correlation coefficient R 2 It is above 0.85.

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