JP4276589B2 - Electrode step absorbing printing paste and method for producing multilayer ceramic electronic component - Google Patents

Description

  The present invention relates to an electrode step absorbing printing paste used for manufacturing a multilayer ceramic electronic component and a method for manufacturing the multilayer ceramic electronic component using the paste.

  In a multilayer ceramic capacitor as an example of a multilayer ceramic electronic component, a ceramic green sheet is usually formed on a carrier sheet using a dielectric paste by a doctor blade method or the like, and a conductive paste for forming an internal electrode is formed thereon. The pattern is printed and dried to form an internal electrode pattern. Thereafter, the ceramic green sheet is peeled off from the carrier sheet and laminated to a desired number of layers.

  Here, two types of lamination methods are known: a method of peeling the ceramic green sheet from the carrier sheet before lamination (sheet method) and a method of peeling the carrier sheet after lamination pressure bonding (printing method). There is no big difference. Finally, this laminate is cut into chips to produce green chips. After firing these green chips, external electrodes are formed to obtain a multilayer ceramic capacitor.

  By the way, in recent years, electronic devices are becoming lighter, thinner and shorter. Along with this, further downsizing and higher capacity are being promoted also in the multilayer ceramic capacitor used in the electronic device. The most effective way to reduce the size and increase the capacity of multilayer ceramic capacitors is to make both internal electrodes and dielectric layers as thin as possible (thinner layers) and stack them as much as possible ( Multi-layered).

  However, when the ceramic green sheets and the internal electrode patterns are alternately laminated like a multilayer ceramic capacitor, gaps (blank spaces) in which no electrodes are formed on the same row of the internal electrode patterns sandwiched between the ceramic green sheets. Pattern portion) is formed. Due to the blank pattern portion, a step is formed with the portion where the internal electrode pattern exists, and this causes problems such as deformation of the product chip, cracks, and delamination between sheets. In particular, when the thickness of the dielectric layer per layer is further reduced to about the thickness of the internal electrode in order to increase the capacity of the capacitor, the dielectric layer is likely to be cut at the portion where the step is generated. Short circuit defects due to short circuits between internal electrodes tend to occur, and the defect rate tends to increase.

  Therefore, in order to solve various problems caused by such steps in recent years, an electrode step absorbing printing paste is formed in a gap (blank pattern portion) where no internal electrode is formed following the formation of the internal electrode (internal electrode pattern). A technique is known in which a blank pattern layer is formed and laminated while the formation surface is flattened. The internal electrode pattern and the blank pattern layer have a negative and positive relationship with the photographic film.

  As the electrode level difference absorbing printing paste, a ceramic powder dispersed in an organic vehicle in which an organic binder is dissolved in a solvent is used as in the case of a dielectric paste for forming a ceramic green sheet.

  In the dielectric paste for forming the ceramic green sheet, for example, butyral resin is used as the organic binder in the organic vehicle, but in the electrode step absorbing printing paste, as the organic binder in the corresponding organic vehicle. Ethyl cellulose is used. The reason is that the printing suitability by screen printing or the like is taken into consideration. On the other hand, terpineol and the like have been used as the solvent in the organic vehicle (see Patent Documents 1 and 2).

  However, when printing paste for electrode step absorption using terpineol as a solvent is used in combination with a ceramic green sheet using butyral resin as the organic binder, the solvent in the paste swells or dissolves the organic binder in the ceramic green sheet. The so-called “sheet attack” phenomenon occurs.

  Such a sheet attack phenomenon is not a practical problem as long as the ceramic green sheet is relatively thick. However, when a sheet attack phenomenon occurs when the thickness of the ceramic green sheet is as thin as 5 μm or less, for example, when the ceramic green sheet is peeled off from a carrier sheet such as a PET film after printing the electrode level difference absorbing printing paste, the ceramic green sheet Is difficult to peel off. When the ceramic green sheet is difficult to peel off, wrinkles, holes, cracks, etc. occur in the ceramic green sheet due to this influence, and a normal laminate cannot be obtained in the lamination process. If a normal laminated body cannot be obtained, the final multilayer ceramic electronic component may have short-circuit failure, breakdown voltage failure (IR degradation), or delamination phenomenon (delamination) between the dielectric layer and the internal electrode layer. Occurred, leading to a decrease in yield.

  Although it is not an electrode level difference absorbing printing paste, as a solvent that does not dissolve the butyral resin that can improve this sheet attack phenomenon, dihydroterpineol is used in Patent Document 3 and dihydroterpine is used in Patent Document 4 as a solvent that can improve the sheet attack phenomenon. A conductive paste using pinyl acetate has been proposed. These solvents are also disclosed in Patent Document 2.

  By the way, a method of forming a blank pattern layer using a screen printing method will be described. First, a screen mesh having a plate film (resist) having the same pattern as the internal electrode pattern is prepared, and this is formed on a ceramic green sheet. Arrange them at intervals. Next, after placing the electrode level difference absorbing printing paste on the screen mesh, a spatula-like rubber plate called a squeegee is used and moved while being pressed against the inner surface of the screen mesh. At this time, the mesh portion pressed by the squeegee is curved downwardly in conjunction with the moving direction of the squeegee and comes into contact with the ceramic green sheet. At the same time, the paste placed on the screen mesh is the screen mesh plate film. A blank pattern layer is formed on the surface of the ceramic green sheet which is extruded from a portion having no blank (a portion forming a blank pattern layer) and has a negative and positive relationship with the internal electrode pattern.

  However, when dihydroterpineol or dihydroterpinyl acetate is used as the solvent for the electrode step absorption printing paste, there is a problem that the viscosity change of the paste with time is large. For this reason, at the beginning of printing, a blank pattern layer can be formed on the ceramic green sheet with the desired viscosity and with the same predetermined thickness as the internal electrode pattern. Thickness cannot be formed. Furthermore, because the tack of the paste itself is strong, the plate release property is poor, and when the screen mesh is separated from the ceramic green sheet, a force acts to peel the ceramic green sheet from the carrier sheet, and in some cases the ceramic green sheet It is peeled off from the carrier sheet, causing wrinkles and cracks.

  The above-mentioned problems such as changes in viscosity of the paste over time, poor release properties, and wrinkles and cracks in the ceramic green sheet tend to be manifested by multilayer ceramic electronic components that require recent thin layer multilayering.

Therefore, as long as such a conventional electrode level difference absorbing printing paste is used, there is a limit to the reduction in size and increase in capacity of the multilayer ceramic electronic component.
JP-A-9-106925 JP 2001-167971 A Japanese Patent Laid-Open No. 9-17687 Japanese Patent No. 2976268

  The object of the present invention is used to produce a multilayer ceramic electronic component, has little change in viscosity with time, good release properties, moderate adhesion to ceramic green sheets, and causes sheet attack. There is provided a printing paste for absorbing no electrode step and a method for producing a multilayer ceramic electronic component using the paste.

  The present inventors have found that by using a specific solvent in the electrode level difference absorbing printing paste, the change in viscosity with time is small, and as a result, the change with time in the film thickness can be suppressed when the blank pattern layer is formed. Further, it has been found that by using this solvent, the separation property from the screen mesh plate used in screen printing can be improved, and as a result, the yield reduction of product chips can be suppressed.

That is, according to the present invention, an electrode step absorption printing paste used for producing a multilayer ceramic electronic component,
Used in combination with a ceramic green sheet with a thickness of 5 μm or less containing butyral resin,
Including ceramic powder and organic vehicle;
There is provided an electrode level difference absorbing printing paste characterized in that the solvent in the organic vehicle contains terpinyl acetate as a main component.

According to the present invention, a step of forming a green ceramic laminate by alternately stacking a plurality of ceramic green sheets containing butyral resin and having a thickness of 5 μm or less and a predetermined pattern of electrode layers;
A step of firing the laminate, and a method of manufacturing an electronic component comprising:
Before forming the laminate, a blank pattern layer having a thickness substantially the same as that of the electrode layer is formed in a gap portion of the electrode layer having a predetermined pattern, and electrode step absorption is performed to form the blank pattern layer. As a printing paste for use, there is provided a method for producing a multilayer ceramic electronic component characterized in that the above-described electrode level difference absorbing printing paste is used.

  Preferably, the solvent in the organic vehicle is contained in an amount of 50 to 240 parts by weight with respect to 100 parts by weight of the ceramic powder.

  The electrode level difference absorbing print paste of the present invention usually contains an organic binder as a component of the organic vehicle together with the solvent. Therefore, preferably, the organic binder in the organic vehicle contains ethyl cellulose as a main component and is contained in an amount of 2.5 to 16 parts by weight with respect to 100 parts by weight of the ceramic powder.

  Preferably, the ceramic powder contained in the electrode level difference absorbing printing paste is the same as the ceramic powder contained in the paste for forming the ceramic green sheet. This is because the blank pattern layer is a portion integrated with the green sheet after firing.

  Preferably, the electrode level difference absorbing printing paste contains ceramic powder in a proportion of 30 to 50% by weight, more preferably 40 to 50% by weight, based on the entire paste. When the content ratio of the ceramic powder is too small, the viscosity of the paste becomes small and printing tends to be difficult. Moreover, when there is too much content rate of ceramic powder, it exists in the tendency for it to become difficult to make printing thickness thin.

  The electrode level difference absorbing printing paste of the present invention may contain additives such as a plasticizer and an electrification remover as necessary.

  The terpinyl acetate used in the solvent for the electrode level difference absorbing print paste in the present invention sufficiently dissolves ethyl cellulose generally used in the organic binder of the electrode level difference absorbing print paste (good rheology). For this reason, the electrode level difference absorbing printing paste using this solvent has little change in viscosity over time.

  The level of solubility can be determined by, for example, creep characteristics and tan δ, but the electrode level difference absorbing print paste of the present invention has excellent creep characteristics and tan δ (see Example 1). For this reason, it is considered that ethyl cellulose contained as a binder in the electrode level difference absorbing print paste is easily adsorbed to the ceramic powder, and the dispersion is stabilized, and as a result, the viscosity change with time of the electrode level difference absorbing print paste is reduced. . By reducing the change in viscosity over time, it is possible to suppress the change in film thickness over time when the blank pattern layer is formed.

  Note that creep characteristics and tan δ are both indices for determining solubility. When a paste with a certain viscosity is dropped on a substrate or the like, the paste hung on the substrate tends to become flat (leveled) naturally, but the creep property means the ease of leveling of this paste. It is an indicator to show. A good creep characteristic means that the leveling property is excellent, and as a result, it is considered that the solubility is high (well dissolved). The terpinyl acetate used in the present invention was found to have the most excellent creep characteristics as compared with terpineol, dihydroterpineol, dihydroterpinel acetate and the like (see FIG. 3).

  Tan δ is an index for determining dynamic viscoelasticity, and the lower the tan δ value, the more elastic and less leveling, while the higher the tan δ value, the more inelastic and easier to level. It is considered that the larger tan δ, the better the dynamic viscoelasticity, that is, the better the leveling property and the higher the solubility. The terpinyl acetate used in the present invention was found to be superior in tan δ as compared with incompatible dihydroterpineol and dihydroterpinel acetate excluding terpineol (see FIG. 4).

  Further, the electrode level difference absorbing printing paste of the present invention has improved plate release from the screen mesh used in screen printing. For this reason, it is possible to effectively suppress the yield reduction of the product chips.

  Moreover, the adhesiveness with respect to a ceramic green sheet is moderately controlled with the printing paste for electrode level | step difference absorptions of this invention with the plate release characteristic of a paste. For this reason, when the screen mesh returns to the original position after the screen printing is completed, the ceramic green sheet is not peeled off from the carrier sheet, and the ceramic green sheet is not wrinkled or cracked.

  Further, terpinyl acetate used as a solvent for the electrode level difference absorbing printing paste does not dissolve or swell the butyral resin contained as an organic binder in the ceramic green sheet (incompatible). For this reason, the electrode level difference absorbing paste using this solvent also has a sheet attack preventing effect, although it is secondary. Therefore, even when the thickness of the ceramic green sheet is as thin as 5 μm or less, for example, when the ceramic green sheet is peeled off from the carrier sheet such as a PET film after printing the electrode level difference absorbing printing paste, the peelability of the ceramic green sheet is improved. It is possible to effectively suppress the generation of wrinkles, holes, cracks, etc. in the ceramic green sheet. That is, even if the ceramic green sheet is made thinner than before, the sheet attack phenomenon does not occur. As a result, even when a very thin ceramic green sheet having a thickness of 5 μm or less is applied, a normal laminate can be obtained. In the final multilayer ceramic electronic component, short circuit failure, withstand voltage failure (IR degradation), dielectric layer The possibility of causing delamination between the electrode layer and the internal electrode layer is reduced.

  From the above, the electrode level difference absorbing printing paste of the present invention is extremely useful for downsizing and increasing the capacity of the final multilayer ceramic electronic component.

  That is, according to the present invention, it is used for producing a multilayer ceramic electronic component, has little change in viscosity with time, has good release properties, has an adequate adhesion to a ceramic green sheet, and has a sheet attack. The electrode level difference absorbing printing paste that does not cause the problem and the method for manufacturing the multilayer ceramic electronic component using the paste can be provided.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention.
2 (A) to 2 (C) are cross-sectional views showing a part of the manufacturing process of the multilayer ceramic capacitor of FIG.
FIG. 3 shows the creep characteristics for each solvent, and is a graph showing the fluctuation of the maximum creep value with respect to the standing days,
FIG. 4 is a graph showing the tan δ for each solvent and showing the variation of the tan δ value with respect to the standing days.

  In the present embodiment, a multilayer ceramic capacitor will be described as an example of a multilayer ceramic electronic component.

Multilayer Ceramic Capacitor As shown in FIG. 1, a multilayer ceramic capacitor 1 according to an embodiment of the present invention includes a capacitor body 10 having a configuration in which dielectric layers 2 and internal electrode layers 3 are alternately stacked. A pair of external electrodes 4, 4 are formed at both ends of the capacitor body 10 and are electrically connected to the internal electrode layers 3 arranged alternately in the body 10. The internal electrode layers 3 are laminated so that the side end faces are alternately exposed on the surfaces of the two opposite ends of the capacitor body 10. The pair of external electrodes 4, 4 are formed at both ends of the capacitor body 10 and are connected to the exposed end surfaces of the alternately arranged internal electrode layers 3 to constitute a capacitor circuit.

  The outer shape and dimensions of the capacitor body 10 are not particularly limited and can be appropriately set depending on the application. Usually, the outer shape is substantially a rectangular parallelepiped shape, and the dimensions are usually vertical (0.4 to 5.6 mm) × It can be about horizontal (0.2-5.0 mm) × height (0.2-1.9 mm).

  The dielectric layer 2 is formed by firing a ceramic green sheet 30 shown in FIGS. 2A to 2C, which will be described later, and the material thereof is not particularly limited. For example, calcium titanate, strontium titanate and And / or a dielectric material such as barium titanate. In this embodiment, the thickness of the dielectric layer 2 is preferably 5 μm or less, more preferably 3 μm or less.

  The internal electrode layer 3 is formed by firing an electrode layer 40 composed of a conductive paste having a predetermined pattern shown in FIGS. 2B and 2C described later. The thickness of the internal electrode layer 3 is preferably 2 μm or less, more preferably 1.5 μm or less.

  As the material of the external electrode 4, copper, a copper alloy, nickel, a nickel alloy, or the like is usually used, but silver, a silver-palladium alloy, or the like can also be used. The thickness of the external electrode 4 is not particularly limited, but is usually about 10 to 50 μm.

Method for Manufacturing Multilayer Ceramic Capacitor Next, an example of a method for manufacturing the multilayer ceramic capacitor 1 according to this embodiment will be described.

Preparation of Dielectric Paste (1) First, a dielectric paste is prepared in order to manufacture a ceramic green sheet that will constitute the dielectric layer 2 shown in FIG. 1 after firing.

  In the present embodiment, the dielectric paste is composed of an organic solvent-based paste obtained by kneading ceramic powder and an organic vehicle.

  The ceramic powder can be appropriately selected from various compounds to be complex oxides and oxides, such as carbonates, nitrates, hydroxides, organometallic compounds, and the like, and can be used as a mixture. The ceramic powder is usually used as a powder having an average particle size of 2.0 μm or less, preferably about 0.1 to 0.8 μm. In order to form a very thin ceramic green sheet, it is desirable to use a powder finer than the thickness of the ceramic green sheet.

  In this embodiment, polyvinyl butyral is used as the binder used in the organic vehicle. The degree of polymerization of the polyvinyl butyral is preferably 300 to 2400, more preferably 500 to 2000. The degree of butyralization of the resin is preferably 50 to 81.6 mol%, more preferably 63 to 80 mol%, and the amount of residual acetyl groups is preferably less than 6%, more preferably 3% or less.

  The organic solvent used in the organic vehicle is not particularly limited, and methyl ethyl ketone, butyl carbitol, acetone, toluene and the like are used.

  Content of each component in a dielectric paste is not specifically limited, For example, a dielectric paste can be prepared so that about 1 to about 50 weight% of solvent may be included.

  The dielectric paste may contain additives selected from various dispersants, plasticizers, dielectrics, subcomponent compounds, glass frit, insulators, and the like, if necessary. When these additives are added to the dielectric paste, the total content is desirably about 10% by weight or less.

  In this embodiment, since polyvinyl butyral is used for the organic binder in the organic vehicle, the plasticizer content in this case is preferably about 25 to about 100 parts by weight with respect to 100 parts by weight of the organic binder.

Formation of Ceramic Green Sheet (2) Next, using this dielectric paste, a doctor blade method or the like, as shown in FIG. The ceramic green sheet 30 is preferably formed with a thickness of about 0.5 to 10 μm.

  As the carrier sheet 20, for example, a PET film or the like is used, and a film coated with silicone or the like is preferable in order to improve peelability. Although the thickness of the carrier sheet 20 is not specifically limited, Preferably it is 5-100 micrometers.

  The ceramic green sheet 30 is dried after being formed on the carrier sheet 20. The drying temperature of the ceramic green sheet 30 is preferably 50 to 100 ° C., and the drying time is preferably 1 to 20 minutes.

  The thickness of the ceramic green sheet 30 after drying shrinks to a thickness of 5 to 25% as compared with that before drying. In this embodiment, the thickness of the ceramic green sheet 30 after drying is formed to be 5 μm or less, preferably 3 μm or less. This is in order to meet the demand for thinner layers in recent years.

Formation of Electrode Layer (3) Next, as shown in FIG. 2 (B), on the surface of the ceramic green sheet 30 formed on the carrier sheet 20, a predetermined pattern that becomes the internal electrode layer 3 shown in FIG. 1 after firing. The electrode layer (internal electrode pattern) 40 is formed.

  The thickness of the electrode layer 40 is 2 μm or less, preferably 0.5 to 1.5 μm. If the thickness of the electrode layer 40 is too thick, the number of stacked layers must be reduced, and the acquired capacity is reduced, making it difficult to increase the capacity. On the other hand, if the thickness is too thin, it is difficult to form uniformly, and electrode breakage is likely to occur.

  The thickness of the electrode layer 40 is in the above range in the current technology, but it is more desirable that the electrode layer 40 be thin in a range where the electrode is not interrupted.

  The method for forming the electrode layer 40 is not particularly limited as long as the layer can be formed uniformly, but in this embodiment, a screen printing method using a conductive paste is used.

  The conductive paste used in the present embodiment contains a conductive powder and an organic vehicle.

  Although it does not specifically limit as electroconductive powder, It is preferable to comprise by at least 1 sort (s) chosen from Cu, Ni, and these alloys, More preferably, it comprises Ni or Ni alloy, and also these mixtures. .

  Ni or an Ni alloy is preferably an alloy of Ni and at least one element selected from Mn, Cr, Co, and Al, and the Ni content in the alloy is preferably 95% by weight or more. In addition, in Ni or Ni alloy, various trace components, such as P, Fe, and Mg, may be contained about 0.1 wt% or less.

  Such a conductive powder is not particularly limited in shape, such as spherical or flake shaped, and may be a mixture of these shapes. The particle diameter of the conductive powder is usually 0.5 mm or less, preferably about 0.01 to 0.4 μm in the case of a spherical shape. This is to realize the thinning more surely.

  The conductive powder is preferably contained in the conductive paste at 30 to 60% by weight, more preferably 40 to 50% by weight.

  The organic vehicle contains an organic binder and a solvent as main components.

  Examples of the organic binder include ethyl cellulose, acrylic resin, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, polyolefin, polyurethane, polystyrene, and copolymers thereof. In this embodiment, ethyl cellulose is the main component. It is preferable. When ethyl cellulose is the main component of the organic binder, the content of ethyl cellulose in the binder is preferably 95% by weight or more, and more preferably 100% by weight. Resins that can be used in combination with ethyl cellulose, although in very small amounts, include acrylic resins and polyvinyl butyral resins.

  The organic binder is preferably contained in the conductive paste in an amount of 1 to 10 parts by weight with respect to 100 parts by weight of the conductive powder.

  As the solvent, any known solvent such as terpineol, butyl carbitol, and kerosene can be used. However, in this embodiment, it is preferable to use terpinyl acetate as a main component. This is because, by using terpinyl acetate as a main component, the same effects as those in the electrode level difference absorbing paste described later can be obtained.

  When terpinyl acetate is a main component as a solvent, the content of terpinyl acetate in the solvent is preferably 95% by weight or more, and more preferably 100% by weight. Solvents that can be used in combination with terpinyl acetate, although in trace amounts, include terpineol and dihydroterpineol.

  The solvent is preferably contained in the conductive paste in an amount of 50 to 150 parts by weight, more preferably 80 to 100 parts by weight with respect to 100 parts by weight of the conductive powder.

  The total content of the binder and the solvent in the organic vehicle is preferably 95% by weight or more, and more preferably 100% by weight. There are plasticizers, leveling agents and the like that can be contained in an organic vehicle together with a binder and a solvent, although only in a very small amount.

  In the conductive paste, the same ceramic powder as the ceramic powder contained in the dielectric paste may be contained as a co-material. The common material has an effect of suppressing the sintering of the conductive powder in the firing process. The ceramic powder used as the co-material is preferably contained in the conductive paste in an amount of 5 to 30 parts by weight with respect to 100 parts by weight of the conductive powder. When the amount of the co-material is too small, the sintering suppressing effect of the conductive powder is lowered, the lineability (continuity) of the internal electrode layer 3 after firing is deteriorated, and the apparent dielectric constant is lowered. On the other hand, when the amount of the co-material is too large, the linearity of the internal electrode layer 3 after firing tends to deteriorate, and the apparent dielectric constant tends to decrease.

  In order to improve adhesion, the conductive paste may contain a plasticizer. The plasticizer is not particularly limited, and examples thereof include phthalic acid esters such as benzylbutyl phthalate (BBP), adipic acid, phosphoric acid esters, and glycols. The plasticizer is contained in an amount of preferably 25 to 150 parts by weight, more preferably 25 to 100 parts by weight with respect to 100 parts by weight of the organic binder in the organic vehicle. By adding the plasticizer, the adhesive force of the electrode layer 40 formed using the paste is increased, and the adhesive force between the electrode layer 40 and the ceramic green sheet 30 is improved. In order to obtain such an effect, the amount of the plasticizer added is preferably 25 parts by weight or more. However, if the addition amount exceeds 150 parts by weight, an excessive plasticizer oozes out from the electrode layer 40 formed using the paste, which is not preferable.

The viscosity of the conductive paste is preferably 1 to 1 when measured using a VISCMETER HBDVI + manufactured by BROOKFIELD under conditions of a spindle (SC _4-14 ) / chamber (6R), a liquid temperature of 25 ° C., and a slip rate of 4S ⁻¹ . 20 Pa · s, more preferably 3 to 15 Pa · s.

  The conductive paste can be obtained by kneading the above components with a ball mill or the like to form a slurry.

Formation of Blank Pattern Layer (4) In this embodiment, the electrode layer 40 shown in FIG. 2B is formed after or before the electrode layer 40 having a predetermined pattern is formed on the surface of the ceramic green sheet 30 by the printing method. As shown in FIG. 2C, a blank pattern layer 60 having substantially the same thickness as that of the electrode layer 40 is formed in the surface gap (blank pattern portion 50) of the ceramic green sheet 30 on which no is formed. The reason why the thickness of the blank pattern layer 60 is made substantially the same as that of the electrode layer 40 is that a step is formed unless it is substantially the same.

  In this embodiment, the blank pattern layer 60 is formed by a screen printing method using an electrode level difference absorbing printing paste.

  The electrode level difference absorbing printing paste used in the present embodiment contains ceramic powder and an organic vehicle.

  As the ceramic powder, one having the same composition and the same average particle size as the ceramic powder contained in the ceramic green sheet 30 is used.

  The ceramic powder is preferably contained in the electrode level difference absorbing printing paste in an amount of 25 to 70% by weight, more preferably 30 to 60% by weight. If the content of the ceramic powder is too small, the paste viscosity becomes small and printing is difficult. Moreover, when there is too much content rate of ceramic powder, it exists in the tendency for it to become difficult to make printing thickness thin.

  The organic vehicle contains a binder and a solvent as main components.

  As the binder, it is preferable that ethyl cellulose is a main component in the present embodiment. The content of ethyl cellulose in the binder is preferably 95% by weight or more, and more preferably 100% by weight. Resins that can be used in combination with ethyl cellulose, although in very small amounts, include acrylic resins and polyvinyl butyral resins.

  The binder is contained in the electrode level difference absorbing print paste, preferably 2.5 to 16 parts by weight with respect to 100 parts by weight of the ceramic powder. If the amount of the binder is too large or too small, the printing suitability and accuracy such as leveling and detachability are deteriorated.

  The solvent is mainly composed of terpinyl acetate. The content of terpinyl acetate in the solvent is preferably 95% by weight or more, and more preferably 100% by weight. Solvents that can be used in combination with terpinyl acetate, although in trace amounts, include terpineol and dihydroterpineol.

  The solvent is contained in the electrode level difference absorbing printing paste in an amount of preferably 50 to 240 parts by weight, more preferably 80 to 200 parts by weight, based on 100 parts by weight of the ceramic powder. If the amount of the solvent is too small, the viscosity is high, the printing suitability and accuracy are deteriorated and the thickness is increased. If the amount is too large, the viscosity is low and the paste drips from the screen mesh, resulting in inconveniences that printability and accuracy deteriorate.

  In addition, the electrode level difference absorbing printing paste may contain various additives such as a dispersant, a plasticizer and / or an adhesive and an antistatic agent.

  The dispersant is not particularly limited. For example, a polymer material such as an ester polymer or carboxylic acid is used, and the content thereof is preferably 0.25 to 1. with respect to 100 parts by weight of ceramic powder. 5 parts by weight, more preferably 0.5 to 1.0 parts by weight is preferably contained.

  The plasticizer is not particularly limited, and examples thereof include phthalic acid esters such as benzylbutyl phthalate (BBP), adipic acid, phosphoric acid esters, and glycols. In the present embodiment, preferably, dioctyl adipate (DOA), butyl butylene glycol phthalate (BPBG), didodecyl phthalate (DDP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), dioctyl phthalate ( DOP), dibutyl sebacate and the like are used. Of these, dioctyl phthalate (DOP) is particularly preferable. The content of the plasticizer is desirably 10 to 200 parts by weight, more preferably 50 to 100 parts by weight with respect to 100 parts by weight of the binder in the organic vehicle.

  The antistatic agent is not particularly limited. For example, an imidazoline-based antistatic agent is used, and the content thereof is 0.1 to 0.75 parts by weight, more preferably 100 parts by weight of the ceramic powder. It is preferable to contain by 0.25-0.5 weight part.

The viscosity of the electrode level difference absorbing printing paste is preferably measured using a VISCOMETER HBDVI + manufactured by BROOKFIELD under the conditions of spindle (SC _4-14 ) / chamber (6R), liquid temperature 25 ° C., slip rate 4S ^−1. Is 1 to 20 Pa · s, more preferably 3 to 15 Pa · s.

  The electrode level difference absorbing printing paste can be obtained by kneading the above components with a ball mill or the like to form a slurry.

  Since the electrode level difference absorbing printing paste of this embodiment contains terpinyl acetate as a solvent, the viscosity change with time is small. Specifically, the viscosity change rate when measuring the viscosity V0 at the time of preparation, the viscosity V1 after 1 day of standing, the viscosity V7 after 7 days of standing, and the viscosity V30 after 30 days of standing are extremely high. It is small and changes in viscosity with time are suppressed.

  The electrode level difference absorbing printing paste of the present embodiment has moderately controlled separation from the screen mesh plate used in screen printing and adhesion to the ceramic green sheet 30. See Example 3 for details.

  This electrode level difference absorbing print paste is printed on the blank pattern portion 50 between the electrode layers 40 shown in FIG. Thereafter, the electrode layer 40 and the blank pattern layer 60 are dried as necessary. The drying temperature is not particularly limited, but is preferably 50 to 120 ° C., and the drying time is preferably 1 to 15 minutes.

Preparation of Green Chip, baking, etc. (5) Next, above that, by stacking a plurality of ceramic green sheets 30 on which the electrode layer 40 and the blank pattern layer 60 is formed on the surface of the predetermined pattern, to produce a green chip The external electrode paste is printed or transferred onto the capacitor body 10 formed of a sintered body, which is formed through a binder removal process, a baking process, and an annealing process performed as necessary, and then fired. 4 and 4 are formed, and the multilayer ceramic capacitor 1 is manufactured.

Effects of this embodiment In this embodiment, terpinyl acetate is used as a solvent for the electrode level difference absorbing printing paste. For this reason, the time-dependent viscosity change of the electrode level | step difference absorption printing paste decreases, and it can suppress the time-dependent change of a film thickness at the time of blank pattern layer formation.

  In addition, the electrode level difference absorbing printing paste of this embodiment has improved plate release from a screen mesh plate used in screen printing. For this reason, it is possible to effectively suppress the yield reduction of the product chips.

  Moreover, the adhesiveness with respect to a ceramic green sheet is moderately controlled with the printing paste for electrode level | step difference absorption of this embodiment with the release of a paste. For this reason, when the screen mesh returns to the original position after the screen printing is completed, the ceramic green sheet is not peeled off from the carrier sheet, and the ceramic green sheet is not wrinkled or cracked.

  Moreover, the terpinyl acetate used as the solvent for the electrode level difference absorbing printing paste does not dissolve or swell polyvinyl butyral contained as a binder in the ceramic green sheet. That is, since no sheet attack is generated, even when the thickness of the ceramic green sheet is as thin as 5 μm or less, the peelability of the ceramic green sheet is improved when the ceramic green sheet is peeled from the carrier sheet after printing the electrode level difference absorbing print paste. In addition, the generation of wrinkles, holes, cracks, etc. in the ceramic green sheet can be effectively suppressed.

  That is, even if the ceramic green sheet is made thinner than before, the sheet attack phenomenon does not occur. As a result, even when a very thin ceramic green sheet having a thickness of 5 μm or less is applied, a normal laminate can be obtained. In the final multilayer ceramic electronic component, short circuit failure, withstand voltage failure (IR degradation), dielectric layer The possibility of causing delamination between the electrode layer and the internal electrode layer is reduced.

  As described above, the electrode level difference absorbing printing paste of this embodiment is extremely useful for reducing the size and increasing the capacity of the final electronic component.

Other Embodiments The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. it can.

  For example, in the above-described embodiment, the multilayer ceramic capacitor is exemplified as the electronic component according to the present invention. However, the electronic component according to the present invention is not limited to the multilayer ceramic capacitor and can be applied to a multilayer ceramic substrate or the like. It is.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.

Example 1
Preparation of Organic Vehicle Ethyl cellulose as an organic binder and the solvents shown in Table 1 were prepared, and 8 parts by weight of the binder was dissolved with respect to 100 parts by weight of each solvent to obtain an organic vehicle.

Evaluation of Creep Characteristics and Tan δ Changes in “creep characteristics” and “tan δ” of the obtained organic vehicle were observed.

“Creep characteristics (creep measurement)” is a measurement of the fluctuation of the maximum creep value when a stress of 1 Pa is applied to the obtained organic vehicle using a viscosity / viscoelasticity measuring device (Rheostress RS1, manufactured by Eihiro Seiki Co., Ltd.). The results are shown in FIG. It is considered that the larger the maximum creep (displacement) value with respect to the standing days, the better the creep characteristics, that is, the better the leveling property and the higher the solubility (well dissolved). When the solubility is high, the viscosity change with time is small.
As shown in FIG. 3, it was confirmed that the sample using terpinyl acetate was most excellent in creep characteristics as compared with the sample using terpineol, dihydroterpineol, and dihydroterpinel acetate.

In “tan δ (dynamic viscoelasticity measurement)”, the variation of the tan δ value when a stress of 10 Pa was applied to the obtained organic vehicle was measured with the same device as described above, and the result is shown in FIG. The lower the tan δ value, the more elastic and less leveling, while the higher the tan δ value, the more inelastic and easy to level. It is considered that the larger the tan δ value with respect to the standing days, the better the dynamic viscoelasticity, that is, the better the leveling property and the higher the solubility. When the solubility is high, the viscosity change with time is small.
As shown in FIG. 4, it was confirmed that the sample using terpinyl acetate had a higher tan δ than the sample using incompatible dihydroterpineol or dihydroterpinel acetate excluding terpineol.

Preparation of electrode level difference absorbing printing paste In addition to the binder and each solvent, a BaTiO ₃ ceramic powder having an average particle size of 0.5 μm as a ceramic powder is prepared, and the organic powder is added to 100 parts by weight of the ceramic powder. 75 parts by weight of a vehicle was added, kneaded with a ball mill, and slurried to obtain an electrode step absorbing printing paste.

Measurement of viscosity by standing days Using the obtained electrode level difference absorbing printing paste, viscosity V0 at the time of preparation, viscosity V1 after 1 day of standing, viscosity V7 after 7 days of standing, and viscosity after 30 days of standing. V30 was measured under the conditions of a spindle (SC _4-14 ) / chamber (6R), a liquid temperature of 25 ° C., and a slip rate of 4S ⁻¹ using a VISCMETER HBDVI + apparatus manufactured by BROOKFIELD. The results are shown in Table 1.

  As shown in Table 1, it was confirmed that the paste using terpinyl acetate had the least change in viscosity over time compared to the paste using terpineol, dihydroterpineol, and dihydroterpinel acetate. .

Example 2
Production of Dielectric Paste The same ceramic powder as that used for producing the electrode level difference absorbing printing paste in Example 1, polyvinyl butyral (PVB) as an organic binder, and methanol as a solvent were prepared. Next, 10% by weight of organic binder and 150% by weight of solvent were weighed with respect to the ceramic powder, kneaded with a ball mill, and slurried to obtain a dielectric paste.

Preparation of Test Sample The obtained dielectric paste was applied to a PET film with a predetermined thickness by a doctor blade method and dried to form a ceramic green sheet having a thickness of 3 μm.

  Next, on the obtained ceramic green sheet, an electrode step absorption printing paste containing the terpinyl acetate used in Example 1 was formed in a predetermined pattern by a screen printing method, dried, and about A ceramic green sheet (test sample) having a blank pattern layer of 1.5 μm was obtained.

Evaluation of Test Sample Using the obtained test sample, “presence / absence of sheet attack” and “peelability of PET film from ceramic green sheet” were evaluated.

  “Presence / absence of sheet attack” refers to observing the surface of the ceramic green sheet opposite to the blank pattern layer side (the surface in contact with the PET film) with an electron microscope (SEM), and confirming the degree of dissolution of the ceramic green sheet by the degree of deformation and hue It was done by doing. As a result, dissolution of the ceramic green sheet could not be observed.

  The “peelability of the PET film from the ceramic green sheet” was measured by measuring the peel strength when peeling the PET film from the test sample. The peel strength was measured by attaching a load cell to the end of a 9 cm × 20 cm green sheet with PET (a marginal part that creates a trigger for peeling) with an adhesive tape and measuring the load (load) while moving it upward. . As a result, the peel strength was an appropriate value of 0.57 gf or less. Thereby, while maintaining the required holding force with respect to a ceramic green sheet, the efficiency of peeling work can be expected.

Example 3
The dielectric paste used in Example 2 was applied onto a PET film by a doctor blade method and dried to form a ceramic green sheet having a thickness of 3 μm.

Evaluation of release property from screen mesh plate On each of the prepared ceramic green sheets, the electrode step absorption printing paste containing each solvent used in Example 1 was formed in a predetermined pattern by the screen printing method as in Example 2. And dried to obtain a blank pattern layer having a thickness of about 1.5 μm.

  As a result, all of the blank pattern layers using other solvents (terpineol, dihydroterpineol, dihydroterpinel acetate) other than terpinyl acetate contained wrinkles. On the other hand, it was confirmed that the blank pattern layer using terpinyl acetate had no wrinkles and was excellent in the release property.

  From the above, pastes using terpinyl acetate have the best release properties compared to pastes using terpineol, dihydroterpineol, dihydroterpinel acetate, and adhesion from ceramic green sheets (easiness). It was confirmed that (excellent peelability) was appropriately controlled.

Example 4
Preparation of Conductive Paste Ni particles having an average particle size of 0.3 μm as a conductive powder, ethyl cellulose as a binder, and terpinyl acetate as a solvent were prepared.

  Next, 8 parts by weight of a binder was dissolved with respect to 100 parts by weight of the solvent to prepare an organic vehicle.

  Next, 50 parts by weight of an organic vehicle was added to 100 parts by weight of the conductive powder, kneaded with a ball mill, and slurried to obtain a conductive paste.

Production of Multilayer Ceramic Chip Capacitor Sample Using the dielectric paste produced in Example 2, the electrode step absorption printing paste produced in Example 1, and the conductive paste produced in this example, A multilayer ceramic chip capacitor 1 shown in FIG. 1 was manufactured.

  First, a dielectric paste was applied to a predetermined thickness on a PET film by a doctor blade method and dried to prepare an exterior green sheet having a thickness of 20 μm. Similarly, an interior ceramic green sheet having a thickness of 3 μm was formed. In this embodiment, the interior green sheet is sandwiched between the five exterior green sheets (100 μm). A plurality of ceramic green sheets for interior use were prepared as first green sheets.

  Next, an electrode layer (internal electrode pattern) 40 (see FIG. 2B) having a thickness of about 1.5 μm was formed on the obtained first green sheet by screen printing using a conductive paste. Thereafter, the electrode layer 40 is substantially formed on the blank pattern portion 50 (see FIG. 2B) where the electrode layer 40 is not formed on the first green sheet by a screen printing method using an electrode level difference absorbing printing paste. A blank pattern layer 60 (see FIG. 2C) having the same thickness was formed, and a ceramic green sheet 30 having the electrode layer 40 and the blank pattern layer 60 as shown in FIG. 2C was obtained. In this example, this ceramic green sheet 30 was used as a second green sheet, and a plurality of these were prepared.

Next, the green sheet group was formed by laminating the exterior green sheets until the thickness became 100 μm. On this green sheet group, 200 second green sheets are laminated, and further, an exterior green sheet group is laminated and formed thereon, and heated under conditions of a temperature of 60 ° C. and a pressure of 1.0 ton / cm ^2. -Pressurized to obtain a green ceramic laminate.

  Next, after cutting the obtained laminated body into a predetermined size, binder removal processing, firing and annealing were performed under the following conditions to obtain a sintered body.

  The binder removal was performed under the conditions of a temperature rising rate: 15 ° C./hour, a holding temperature: 280 ° C., a holding time: 8 hours, and a processing atmosphere: an air atmosphere.

Firing is performed at a heating rate of 200 ° C./hour, a holding temperature of 1200 to 1380 ° C., a holding time of 2 hours, a cooling rate of 300 ° C./hour, a processing atmosphere: a reducing atmosphere (oxygen partial pressure: 10 ⁻⁶ Pa to N The mixed gas of ₂ and H ₂ was adjusted by passing water vapor).

  The annealing was performed under the conditions of a holding temperature: 900 ° C., a holding time: 9 hours, a cooling rate: 300 ° C./hour, and a processing atmosphere: a humidified N 2 gas atmosphere. A wetter was used to wet the gas during firing and annealing, and the water temperature was set to 35 ° C.

  Next, after polishing the end face of the obtained sintered body by sand blasting, an In—Ga alloy was applied to form a test electrode to obtain a multilayer ceramic chip capacitor sample.

  The size of the capacitor sample is 1.6 mm long × 0.8 mm wide × 0.8 mm high. The thickness of the dielectric layer 2 sandwiched between the pair of internal electrode layers is about 2 μm, and the thickness of the internal electrode layer 3 is 1. It was 5 μm.

Evaluation of Capacitor Sample The capacitor sample obtained was evaluated for short-circuit failure characteristics, withstand voltage characteristics (IR characteristics), and the presence or absence of delamination.

  About the short circuit defect characteristic, the insulation resistance value after applying DC10V 60 at 25 degreeC was measured using the insulation resistance meter (E2377A multimeter by HEWLETT PACKARD), and 10 or less was made into short circuit defect.

  The presence or absence of delamination was evaluated by polishing 100 capacitor samples and internally observing them with an electron microscope. The number of delamination was shown.

  The results are shown in Table 2.

  As shown in Table 2, those using terpinyl acetate confirmed good results in short circuit failure and delamination.

  That is, as a result of observing the laminate, it was confirmed that the step of the electrode layer between the green sheets was satisfactorily eliminated, and delamination between the sheets and deformation of the laminate could be effectively prevented.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. 2A to 2C are cross-sectional views illustrating a part of the manufacturing process of the multilayer ceramic capacitor of FIG. FIG. 3 shows the creep characteristics for each solvent, and is a graph showing the fluctuation of the maximum creep value with respect to the standing days. FIG. 4 shows tan δ for each solvent, and is a graph showing the variation of the tan δ value with respect to the standing days.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Multilayer ceramic capacitor 10 ... Capacitor body 2 ... Dielectric layer 3 ... Internal electrode layer 4 ... External electrode 20 ... Carrier sheet 30 ... Ceramic green sheet 40 ... Electrode layer (internal electrode pattern)
50 ... margin pattern portion 60 ... margin pattern layer

Claims (6)

An electrode level difference absorbing printing paste used for manufacturing a multilayer ceramic electronic component,
Used in combination with a ceramic green sheet with a thickness of 5 μm or less containing butyral resin,
Including ceramic powder and organic vehicle;
A printing paste for absorbing an electrode step, wherein the solvent in the organic vehicle contains terpinyl acetate as a main component. 2. The electrode level difference absorbing printing paste according to claim 1, wherein the solvent in the organic vehicle is contained in an amount of 50 to 240 parts by weight with respect to 100 parts by weight of the ceramic powder. 3. The electrode level difference absorbing printing paste according to claim 1, wherein the organic binder in the organic vehicle contains ethyl cellulose as a main component and is contained in an amount of 2.5 to 16 parts by weight with respect to 100 parts by weight of the ceramic powder. 4. The electrode level difference absorbing printing paste according to claim 1, wherein the ceramic powder is the same as the ceramic powder contained in the paste for forming the ceramic green sheet. Forming a green ceramic laminate by alternately stacking a plurality of ceramic green sheets having a thickness of 5 μm or less and a predetermined pattern of electrode layers containing butyral resin;
A step of firing the laminate, and a method of manufacturing an electronic component comprising:
Before forming the laminate, a blank pattern layer having substantially the same thickness as the electrode layer is formed in a gap portion of the electrode layer of a predetermined pattern,
A method for manufacturing a multilayer ceramic electronic component, wherein the electrode level difference absorbing print paste according to claim 1 is used as the electrode level difference absorbing print paste for forming the blank pattern layer. The method for manufacturing a multilayer ceramic electronic component according to claim 5, wherein the ceramic powder contained in the electrode level difference absorbing print paste is the same as the ceramic powder contained in the paste for forming the green sheet.

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