阅读说明：本技术 感光性绝缘膏和电子部件 (Photosensitive insulating paste and electronic component ) 是由 近藤健太 田边新平 于 2020-08-10 设计创作，主要内容包括：本发明提供一种煅烧前的分辨率高,且能够兼具煅烧后的光透射抑制和裂纹抑制的感光性绝缘膏和使用该感光性绝缘膏的电子部件。本发明的感光性绝缘膏的特征在于,含有玻璃熔块、第1无机填料、第2无机填料、碱可溶聚合物、感光性单体、光聚合引发剂和溶剂,第1无机填料的折射率为1.7以上,第2无机填料的折射率为1.55以下。另外,本发明提供一种使用本发明的感光性绝缘膏的电子部件。(The invention provides a photosensitive insulating paste which has high resolution before calcination and can inhibit light transmission and crack after calcination, and an electronic component using the photosensitive insulating paste. The photosensitive insulating paste of the present invention is characterized by containing a glass frit, a 1 st inorganic filler, a 2 nd inorganic filler, an alkali-soluble polymer, a photosensitive monomer, a photopolymerization initiator, and a solvent, wherein the refractive index of the 1 st inorganic filler is 1.7 or more, and the refractive index of the 2 nd inorganic filler is 1.55 or less. The present invention also provides an electronic component using the photosensitive insulating paste of the present invention.)

1. A photosensitive insulating paste comprising a glass frit, a 1 st inorganic filler, a 2 nd inorganic filler, an alkali-soluble polymer, a photosensitive monomer, a photopolymerization initiator and a solvent,

the refractive index of the 1 st inorganic filler is 1.7 or more,

the refractive index of the 2 nd inorganic filler is 1.55 or less.

2. The photosensitive insulating paste according to claim 1, wherein the composition ratio of the glass frit in a content of a, the 1 st inorganic filler in B, and the 2 nd inorganic filler in C satisfies a relationship of a + B + C to 100, B: 5 vol% to 20 vol% and C: (25-B) vol% to (40-B) vol%.

3. The photosensitive insulating paste according to claim 1 or 2, wherein the glass frit has a softening point of 700 ℃ or higher and less than 900 ℃ and the 1 st inorganic filler and the 2 nd inorganic filler have a melting point of 950 ℃ or higher.

4. The photosensitive insulating paste according to any one of claims 1 to 3, wherein the 1 st inorganic filler is at least 1 selected from the group consisting of alumina, titania, zirconia, and ceria.

5. The photosensitive insulating paste according to any one of claims 1 to 4, wherein the 2 nd inorganic filler is at least 1 selected from quartz and crystallized glass.

6. An electronic component comprising a laminate having a plurality of internal electrode layers and insulating layers disposed between the internal electrode layers in a lamination direction,

side gap portions are located between both side surfaces of the stacked body and the internal electrode layers, the both side surfaces of the stacked body being parallel to the stacking direction,

the side gap part contains glass, a 1 st inorganic filler and a 2 nd inorganic filler,

the side gap part has an average thickness of 5 to 30 μm,

the refractive index of the 1 st inorganic filler is 1.7 or more,

the refractive index of the 2 nd inorganic filler is 1.55 or less.

7. The electronic component according to claim 6, wherein a void ratio of the side gap portion is 5% or less.

8. The electronic component according to claim 6 or 7, wherein in the predetermined cross section of the side gap portion, when an area of the glass is a, an area of the 1 st inorganic filler is B, and an area of the 2 nd inorganic filler is C, an area ratio satisfies a + B + C of 100 and B: 5% -20%, C: (25-B)% to (40-B)%.

Technical Field

The invention relates to a photosensitive insulating paste and an electronic component.

Background

Conventionally, japanese patent application laid-open No. 2012 and 246176 (patent document 1) have been disclosed as a photosensitive paste used for electronic components. The photosensitive paste is characterized in that a glass powder having a specific composition is used in order to improve the denseness and chemical resistance after firing.

Patent document 1: japanese laid-open patent publication No. 2012-246176

Disclosure of Invention

However, when the photosensitive paste is used for an insulating layer of an electronic component, light transmittance also increases in the insulating layer after firing, and if the thickness between the internal electrode layer and the surface of the electronic component is small, the internal electrode layer can be seen through the surface of the electronic component. Further, since the electronic component does not contain an inorganic filler, the electronic component cannot be prevented from cracking, and therefore, cracks are likely to occur.

On the other hand, a method of mixing a light-shielding inorganic filler with a photosensitive paste to suppress light transmittance after firing has been considered, but there is a problem that light transmittance is also inhibited at the time of photolithographic patterning of the photosensitive paste, and high resolution cannot be obtained. In addition, in order to prevent the internal electrode layers from being seen through the surface of the electronic component, it is conceivable to increase the thickness of the side gap portion of the electronic component, but if the thickness of the side gap portion is increased, the degree of freedom in designing the electronic component is impaired, and therefore, there is a problem that it is difficult to achieve a small size and high performance.

Accordingly, an object of the present invention is to provide a photosensitive insulating paste which has high resolution before firing and can achieve both light transmission suppression and crack suppression after firing, and an electronic component using the photosensitive insulating paste.

The photosensitive insulating paste of the present invention is a photosensitive insulating paste, characterized by containing a glass frit, a 1 st inorganic filler, a 2 nd inorganic filler, an alkali-soluble polymer, a photosensitive monomer, a photopolymerization initiator, and a solvent, wherein the refractive index of the 1 st inorganic filler is 1.7 or more, and the refractive index of the 2 nd inorganic filler is 1.55 or less.

The electronic component of the present invention is an electronic component including a laminate having a plurality of internal electrode layers and insulating layers disposed between the internal electrode layers in a lamination direction, side gap portions located between both side surfaces of the laminate and the internal electrode layers, the both side surfaces of the laminate being parallel to the lamination direction, the side gap portions containing glass, a 1 st inorganic filler and a 2 nd inorganic filler, the side gap portions having an average thickness of 5 μm to 30 μm, the 1 st inorganic filler having a refractive index of 1.7 or more, and the 2 nd inorganic filler having a refractive index of 1.55 or less.

According to the present invention, a photosensitive insulating paste having high resolution before firing and capable of achieving both light transmission suppression and crack suppression after firing, and an electronic component using the photosensitive insulating paste can be provided.

Drawings

Fig. 1 is an external perspective view of a coil electronic component according to an embodiment of the present invention.

Fig. 2 is a line II-II cross-sectional view of the coil electronic component shown in fig. 1.

Fig. 3 is a line III-III cross-sectional view of the coil electronics shown in fig. 1.

Fig. 4 is an explanatory view showing a method of evaluating a crack occurrence load.

Fig. 5(a) shows a state of the insulating layer having a porosity of more than 5%, and (b) shows a state of the insulating layer having a porosity of 5% or less.

Description of the symbols

10-coil electronic component

12 laminated body

12a 1 st end face

12b 2 nd end face

12c the 1 st main surface

12d the 2 nd main surface

12e 1 st side

12f 2 nd side

14 insulating layer

16a, 16b side gap part

20 coil

22a, 22b lead-out electrodes

24 coil conductor layer

26-via conductor layer

30 external electrode

30a 1 st external electrode

30b No. 2 external electrode

50 alumina substrate

52 adhesive

54 ram

A direction of lamination

O axial direction

Detailed Description

1. Photosensitive insulating paste

The photosensitive insulating paste according to the embodiment of the present invention contains a glass frit, a 1 st inorganic filler (inorganic filler for coloring), a 2 nd inorganic filler (transparent inorganic filler), an alkali-soluble polymer, a photosensitive monomer, a photopolymerization initiator, and a solvent. Further, an organic dye is contained as required.

The glass frit may use borosilicate glass (softening point 760 ℃). The glass frit may contain SiO in addition to borosilicate glass₂、B₂O₃、K₂O、Li₂O、CaO、ZnO、Bi₂O₃And/or Al₂O₃Glass of the like, e.g. SiO₂－B₂O₃－K₂O-based glass, SiO₂－B₂O₃－Li₂O-CaO series glass, SiO₂－B₂O₃－Li₂O-CaO-ZnO glass and Bi₂O₃－B₂O₃－SiO₂－Al₂O₃Is a glass. These inorganic components may be combined in 2 or more kinds. The softening point of the glass frit is preferably 700 ℃ or higher and less than 900 ℃.

The refractive index of the glass frit is preferably 1.55 or less, and more preferably equal to the refractive index of the 2 nd inorganic filler.

The 1 st inorganic filler (coloring inorganic filler) is a filler having a refractive index of 1.7 or more. The 1 st inorganic filler preferably has a softening point of 950 ℃ or higher. The 1 st inorganic filler may preferably use alumina. As the 1 st inorganic filler, in addition to alumina, titania, zirconia, ceria, and the like can be used.

The refractive index of the 2 nd inorganic filler (transparent inorganic filler) is 1.55 or less. The 2 nd inorganic filler preferably has a softening point of 950 ℃ or higher. The 2 nd inorganic filler may preferably be quartz. The crystallinity of quartz is not particularly limited. However, crystallized glass may also be used as the transparent inorganic filler.

The refractive index of the 1 st inorganic filler and the 2 nd inorganic filler is a value of the refractive index with respect to light having a wavelength of 589.3nm (sodium D-ray).

The 1 st inorganic filler and the 2 nd inorganic filler preferably have an average particle diameter of 0.1 to 5.0. mu.m, respectively. More preferably, the average particle diameter of each is 0.3 to 3.0. mu.m. If the average particle diameter of each inorganic filler is less than 0.1. mu.m, the paste is difficult to disperse. On the other hand, if the particle diameter of each inorganic filler is larger than 5.0 μm on average, the smoothness of the insulating layer and the groove shape are deformed when the photosensitive insulating paste is used for forming the insulating layer of an electronic component, which is not preferable.

The alkali-soluble polymer contains an acrylic polymer having a carboxyl group in a side chain. The resin containing an acrylic copolymer having a carboxyl group in a side chain can be produced, for example, by copolymerizing an unsaturated carboxylic acid with an ethylenically unsaturated compound.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, vinyl acetic acid, and anhydrides thereof. On the other hand, examples of the ethylenically unsaturated compound include acrylic esters such as methyl acrylate and ethyl acrylate, methacrylic esters such as methyl methacrylate and ethyl methacrylate, and fumaric esters such as monoethyl fumarate.

Further, as the acrylic copolymer having a carboxyl group in a side chain, an acrylic copolymer having an unsaturated bond introduced therein in the following form can be used.

(1) An acrylic monomer having a functional group such as an epoxy group capable of reacting with a carboxyl group in a side chain of the acrylic copolymer.

(2) An unsaturated monocarboxylic acid is reacted with the acrylic copolymer having an epoxy group introduced therein in place of the side chain carboxyl group, and then a saturated or unsaturated polycarboxylic anhydride is further introduced.

Further, the acrylic copolymer having a carboxyl group in a side chain is preferably an acrylic copolymer having a weight average molecular weight (Mw) of 50000 or less and an acid value of 30 to 150.

The photosensitive monomer may be dipentaerythritol monohydroxypentaacrylate. Furthermore, as the photosensitive monomer, in addition to dipentaerythritol monohydroxypentaacrylate, there may be used hexanediol triacrylate, tripropylene glycol triacrylate, trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, stearyl acrylate, tetrahydrofurfuryl acrylate, lauryl acrylate, 2-phenoxyethyl acrylate, isodecyl acrylate, isooctyl acrylate, tridecyl acrylate, caprolactone acrylate, ethoxylated nonylphenol acrylate, 1, 3-butanediol diacrylate, 1, 4-butanediol diacrylate, diethylene glycol diacrylate, tetraethylene glycol diacrylate, triethylene glycol diacrylate, ethoxylated bisphenol A diacrylate, propoxylated neopentyl glycol diacrylate, tris (2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, propoxylated trimethylolpropane triacrylate, propoxylated glycerol triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, and the like. In addition, a compound in which a part or all of acrylate in the molecule of the above compound is changed to methacrylate may be used.

In the photosensitive insulating paste, the composition ratio of the glass frit a, the 1 st inorganic filler B, and the 2 nd inorganic filler C is preferably 100, B: 5 vol% to 20 vol% and C: (25-B) vol% to (40-B) vol%.

An acetophenone-based compound can be used as the photopolymerization initiator.

As the solvent, for example, 1- (2-methoxy-2-methylethoxy) -2-propanol can be used.

Further, azo compounds can be used as the organic dye to be contained if necessary. When the photosensitive insulating paste is used for the photolithography patterning, the organic dye is a UV absorber for fine adjustment of UV transmittance.

2. Method for producing photosensitive insulating paste

Next, a method for producing the photosensitive insulating paste will be described.

The photosensitive insulating paste can be produced by mixing a glass frit, a 1 st inorganic filler (inorganic filler for coloring), a 2 nd inorganic filler (transparent inorganic filler), an alkali-soluble polymer, a photopolymerization initiator, a solvent and an organic dye sufficiently with 3 rolls.

The glass frit may use borosilicate glass (softening point 760 ℃). The glass frit may contain SiO in addition to borosilicate glass₂、B₂O₃、K₂O、Li₂O、CaO、ZnO、Bi₂O₃And/or Al₂O₃Glass of the like, e.g. SiO₂－B₂O₃－K₂O-based glass, SiO₂－B₂O₃－Li₂O-CaO series glass, SiO₂－B₂O₃－Li₂O-CaO-ZnO glass and Bi₂O₃－B₂O₃－SiO₂－Al₂O₃Is a glass. These inorganic components may be combined in 2 or more kinds. The softening point of the glass frit is preferably 700 ℃ or higher and less than 900 ℃.

The 1 st inorganic filler (coloring inorganic filler) is a filler having a refractive index of 1.7 or more. The 1 st inorganic filler preferably has a softening point of 950 ℃ or higher. The 1 st inorganic filler may preferably use alumina. As the 1 st inorganic filler, in addition to alumina, titania, zirconia, ceria, and the like can be used.

The refractive index of the 2 nd inorganic filler (transparent inorganic filler) is 1.55 or less. The 2 nd inorganic filler preferably has a softening point of 950 ℃ or higher. The 2 nd inorganic filler may preferably be quartz. Further, the crystallinity of quartz is not particularly limited. However, crystallized glass may be used as the transparent inorganic filler.

The 1 st inorganic filler and the 2 nd inorganic filler preferably have an average particle diameter of 0.1 to 5.0. mu.m, respectively. More preferably, the average particle diameter of each is 0.3 to 3.0. mu.m.

The alkali-soluble polymer contains an acrylic polymer having a carboxyl group in a side chain. The resin containing an acrylic copolymer having a carboxyl group in a side chain can be produced, for example, by copolymerizing an unsaturated carboxylic acid with an ethylenically unsaturated compound.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, vinyl acetic acid, and anhydrides thereof. On the other hand, examples of the ethylenically unsaturated compound include acrylic esters such as methyl acrylate and ethyl acrylate, methacrylic esters such as methyl methacrylate and ethyl methacrylate, and fumaric esters such as monoethyl fumarate.

Further, as the acrylic copolymer having a carboxyl group in a side chain, an acrylic copolymer having an unsaturated bond introduced therein in the following form can be used.

(1) An acrylic monomer having a functional group such as an epoxy group capable of reacting with a carboxyl group in a side chain of the acrylic copolymer.

(2) An unsaturated monocarboxylic acid is reacted with the acrylic copolymer having an epoxy group introduced therein in place of the side chain carboxyl group, and then a saturated or unsaturated polycarboxylic anhydride is further introduced.

Further, the acrylic copolymer having a carboxyl group in a side chain is preferably an acrylic copolymer having a weight average molecular weight (Mw) of 50000 or less and an acid value of 30 to 150.

The photosensitive monomer may be dipentaerythritol monohydroxypentaacrylate. Furthermore, as the photosensitive monomer, in addition to dipentaerythritol monohydroxypentaacrylate, there may be used hexanediol triacrylate, tripropylene glycol triacrylate, trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, stearyl acrylate, tetrahydrofurfuryl acrylate, lauryl acrylate, 2-phenoxyethyl acrylate, isodecyl acrylate, isooctyl acrylate, tridecyl acrylate, caprolactone acrylate, ethoxylated nonylphenol acrylate, 1, 3-butanediol diacrylate, 1, 4-butanediol diacrylate, diethylene glycol diacrylate, tetraethylene glycol diacrylate, triethylene glycol diacrylate, ethoxylated bisphenol A diacrylate, propoxylated neopentyl glycol diacrylate, tris (2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, propoxylated trimethylolpropane triacrylate, propoxylated glycerol triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, and the like. In addition, a compound in which a part or all of acrylate in the molecule of the above compound is changed to methacrylate may be used.

In the photosensitive insulating paste, the composition ratio of the glass frit a, the 1 st inorganic filler B, and the 2 nd inorganic filler C is preferably 100, B: 5 vol% to 20 vol% and C: (25-B) vol% to (40-B) vol%.

An acetophenone-based compound can be used as the photopolymerization initiator.

As the solvent, for example, 1- (2-methoxy-2-methylethoxy) -2-propanol can be used.

Further, azo compounds can be used as the organic dye to be contained if necessary. When the photosensitive insulating paste is used for the photolithography patterning, the organic dye is a UV absorber for fine adjustment of UV transmittance.

The photosensitive insulating paste of the present invention contains a glass frit, a 1 st inorganic filler (coloring inorganic filler), a 2 nd inorganic filler (transparent inorganic filler), an alkali-soluble polymer, a photosensitive monomer, a photopolymerization initiator, and a solvent, and has a refractive index of the 1 st inorganic filler of 1.7 or more and a refractive index of the 2 nd inorganic filler of 1.55 or less, so that when the photosensitive insulating paste is used for an insulating layer of an electronic component, the light transmittance of the insulating layer can be adjusted by adjusting the content of each inorganic filler.

In the photosensitive insulating paste of the present invention, if the composition ratio of the glass frit content a, the 1 st inorganic filler content B, and the 2 nd inorganic filler content C satisfies a relationship of a + B + C being 100, B: 5 vol% to 20 vol% and C: when the photosensitive insulating paste is used for an insulating layer of an electronic component, the conditions of (25-B) vol% to (40-B) vol% provide high optical transparency before firing, suppress optical transparency after firing, and allow sintering in the insulating layer to sufficiently progress, thereby enabling the ceramic material to exhibit mechanical strength.

Furthermore, if the softening point of the glass frit contained in the photosensitive insulating paste of the present invention is 700 ℃ or more and less than 900 ℃ and the melting points of the 1 st inorganic filler and the 2 nd inorganic filler are 950 ℃ or more, when the photosensitive insulating paste is used for an insulating layer of an electronic component, the melting point of the glass frit is below the firing temperature region, and therefore, melting necessary for firing the glass ceramic occurs, and each inorganic filler does not melt in the firing temperature region, and therefore, the function as each inorganic filler can be exhibited, and therefore, an appropriate firing temperature at which the sinterability of the insulating layer to have a porosity of 5% or less can be ensured can be 850 ℃ to 950 ℃, and the resistance of the sintered coil conductor layer (internal electrode layer) can be reduced.

3. Coil electronic component

Next, a coil electronic component will be described as an example of an electronic component manufactured using the photosensitive insulating paste.

Fig. 1 is an external perspective view showing an embodiment of a coil electronic component. Fig. 2 is a line II-II cross-sectional view of the coil electronic component shown in fig. 1. Fig. 3 is a line III-III cross-sectional view of the coil electronics shown in fig. 1.

As shown in fig. 1 to 3, the coil electronic component 10 includes a laminate 12, a spiral coil 20 provided inside the laminate 12, and an external electrode 30 provided on the laminate 12 and electrically connected to the coil 20.

The coil electronic component 10 is electrically connected to wiring of a circuit board, not shown, via the external electrodes 30. The coil electronic component 10 is used as, for example, an impedance matching coil (matching coil) of a high-frequency circuit, and is used in electronic devices such as a personal computer, a DVD player, a digital camera, a TV, a mobile phone, an automotive electronic product, and a medical and industrial machine. However, the coil electronic component 10 is not limited to this application, and may be used for a tuning circuit, a filter circuit, a rectifying/smoothing circuit, and the like.

The laminate 12 is formed by laminating a plurality of insulating layers 14. The stacked body 12 is formed in a substantially rectangular parallelepiped shape. The laminate 12 has a 1 st end face 12a, a 2 nd end face 12b opposed to the 1 st end face 12a, a 1 st main face 12c connected between the 1 st end face 12a and the 2 nd end face 12b, a 2 nd main face 12d opposed to the 1 st main face 12c, a 1 st side face 12e connected between the 1 st end face 12a and the 2 nd end face 12b and intersecting the 1 st main face 12c perpendicularly, and a 2 nd side face 12f opposed to the 1 st side face 12e on the surface. The 1 st end face 12a, the 2 nd end face 12b, the 1 st side face 12e, and the 2 nd side face 12f are faces parallel to the stacking direction a of the insulating layer 14. Here, "parallel" in the present application is not limited to a strict parallel relationship, but includes a substantially parallel relationship in consideration of a range of actual variation. In addition, the stacked body 12 may have an unclear interface between the plurality of insulating layers 14 due to firing or the like.

The outer shape and size of the laminate 12 are not particularly limited and may be appropriately set according to the application, and the outer shape is generally a rectangular parallelepiped shape, and for example, the x-axis dimension is 0.1mm to 1.0mm, the y-axis dimension is 0.2mm to 1.6mm, and the z-axis dimension is 0.1mm to 1.0 mm.

The insulating layer 14 contains glass, a 1 st inorganic filler and a 2 nd inorganic filler.

Borosilicate glass (softening point 760 ℃ C.) was used as the glass. The glass may contain SiO in addition to borosilicate glass₂、B₂O₃、K₂O、Li₂O、CaO、ZnO、Bi₂O₃And/or Al₂O₃Glass of the like, e.g. SiO₂－B₂O₃－K₂O-based glass, SiO₂－B₂O₃－Li₂O-CaO series glass, SiO₂－B₂O₃－Li₂O-CaO-ZnO glass and Bi₂O₃－B₂O₃－SiO₂－Al₂O₃Is a glass. These inorganic components may beSo as to combine 2 or more. When the laminate 12 is fired at 850 to 950 ℃, the softening point of the glass is preferably 700 ℃ or higher and less than 900 ℃.

The refractive index of the glass is preferably 1.55 or less, and more preferably equivalent to the refractive index of the 2 nd inorganic filler.

The 1 st inorganic filler (coloring inorganic filler) is a filler having a refractive index of 1.7 or more. The 1 st inorganic filler preferably has a softening point of 950 ℃ or higher. The 1 st inorganic filler may preferably use alumina. As the 1 st inorganic filler, in addition to alumina, titania, zirconia, ceria, and the like can be used.

The refractive index of the 2 nd inorganic filler (transparent inorganic filler) is 1.55 or less. The 2 nd inorganic filler preferably has a softening point of 950 ℃ or higher. The 2 nd inorganic filler may preferably be quartz. Further, the crystallinity of quartz is not particularly limited. However, crystallized glass may also be used as the transparent inorganic filler.

When the area of the glass contained in the insulating layer 14 is a, the area of the 1 st inorganic filler is B, and the area of the 2 nd inorganic filler is C, the area ratio of A, B to C is preferably 100, and B: 5% -20%, C: (25-B)% - (40-B)%.

The area ratio can be calculated by polishing the WT cross section of the coil electronic component 10 to 1/2L (center portion in the y-axis direction) to expose the cross section, identifying the glass, the 1 st inorganic filler, and the 2 nd inorganic filler using EDX and SEM, and then calculating the area ratio based on the information of the measurement region.

In the present embodiment, the area ratio and the volume ratio are substantially equal to each other.

The porosity of the laminate 12 is preferably 5% or less.

The porosity can be calculated by polishing the coil electronic component 10 to the center in the y-axis direction to expose the cross section, and subjecting an image obtained by observing the cross section with an SEM to a 2-valued process for brightness, thereby specifying the sintered laminate portion and the remaining void portion. Then, the ratio of the area of the voids to the entire laminate was calculated as a void ratio.

The external electrode 30 has a 1 st external electrode 30a and a 2 nd external electrode 30 b.

The 1 st external electrode 30a is disposed on the surface of the 1 st end face 12a of the laminate 12. At this time, the 1 st external electrode 30a is formed to extend from the 1 st end surface 12a of the laminate 12 and cover a part of each of the 1 st main surface 12c, the 2 nd main surface 12d, the 1 st side surface 12e, and the 2 nd side surface 12 f. The extraction electrode 22a located on the 1 st main surface 12c side in the z-axis direction is connected to the 1 st outer electrode 30 a.

The 2 nd external electrode 30b is disposed on the surface of the 2 nd end face 12b of the laminate 12. At this time, the 2 nd external electrode 30b is formed to extend from the 2 nd end surface 12b of the laminate 12 and cover a part of each of the 1 st main surface 12c, the 2 nd main surface 12d, the 1 st side surface 12e, and the 2 nd side surface 12 f. The extraction electrode 22b located on the 2 nd main surface 12d side in the z-axis direction is connected to the 2 nd outer electrode 30 b.

Accordingly, the external electrodes 30 are connected to both ends of the coil 20 constituting the winding pattern.

In the present embodiment, the lamination direction of the insulating layer 14 and the coil 20 coincides with the z-axis, and the surface of the external electrode 30 is parallel to the x-axis and the y-axis. Note that the x-axis, y-axis, and z-axis are perpendicular to each other. In the coil electronic component 10 shown in fig. 1, the winding axis direction of the coil 20 substantially coincides with the z-axis.

The 1 st and 2 nd external electrodes 30a and 30b are made of a conductive material such as Ag or Cu and glass particles, for example.

The coil 20 is made of, for example, the same conductive material and glass particles as the 1 st and 2 nd external electrodes 30a and 30 b. The coil 20 is wound in a spiral shape along the lamination direction a of the insulating layers 14. In the coil 20, the lead electrode 22a located on the 1 st main surface 12c side is connected to the 1 st external electrode 30a, and in the coil 20, the lead electrode 22b located on the 2 nd main surface 12d side is connected to the 2 nd external electrode 30 b.

The coil 20 is formed in a substantially elliptical shape when viewed in the axial direction O, but is not limited to this shape. The shape of the coil 20 may be, for example, circular, elliptical, rectangular, other polygonal shapes, and the like. The axial direction O of the coil 20 is a direction parallel to the central axis of the spiral around which the coil 20 is wound. The axial direction O of the coil 20 and the lamination direction a of the insulating layers 14 are the same direction.

The coil 20 includes coil conductor layers 24 as a plurality of internal electrode layers wound on the insulating layer 14. The coil conductor layers 24 adjacent to each other in the stacking direction a are electrically connected in series via a via conductor layer 26 penetrating the insulating layer 14 in the thickness direction. In this way, the plurality of coil conductor layers 24 form a spiral while being electrically connected in series with each other. Specifically, the coil 20 has a structure in which a plurality of coil conductor layers 24, which are electrically connected in series with each other and have a winding number of less than 1 cycle, are laminated, and the coil 20 has a spiral shape.

As shown in fig. 3, the laminated body 12 includes a side gap portion 16a between one end of the coil conductor layer 24 in the x-axis direction and the 1 st side surface 12 e. The laminated body 12 includes a side gap portion 16b, and the side gap portion 16b is located between the other end of the coil conductor layer 24 in the x-axis direction and the 2 nd side surface 12 f. The side gap portions 16a, 16b have an average thickness in the x-axis direction of 5 to 30 μm.

The external shape and size of the coil electronic component 10 are not particularly limited and may be appropriately set according to the application, and usually, for example, the dimension in the x-axis direction (W dimension) is 0.1mm to 1.0mm, the dimension in the y-axis direction (L dimension) is 0.2mm to 1.6mm, and the dimension in the z-axis direction (T dimension) is 0.1mm to 1.0 mm.

4. Method for manufacturing coil electronic component

Next, a method for manufacturing the coil electronic component 10 will be described.

First, a photosensitive insulating paste and a photosensitive conductive paste are prepared. The photosensitive insulating paste contains a glass frit, a 1 st inorganic filler and a 2 nd inorganic filler. The photosensitive insulating paste can be prepared by the above-described production method.

Next, an insulating paste is applied to form an outer insulating layer. A photosensitive insulating paste is applied to the outer insulating layer to form a 1 st insulating layer. The insulating paste can be applied by screen printing, for example.

The insulating paste used for forming the outer insulating layer may have the same composition as the photosensitive insulating paste, but may have a composition described below.

(a) Organic binder (Material: acrylic Polymer)

(b) Solvent (Material: 1- (2-methoxy-2-methylethoxy) -2-propanol)

(c) Inorganic filler (material: alumina)

(d) Glass frit (borosilicate glass)

Since the outer insulating layer is a layer not patterned with respect to the organic binder, the outer insulating layer may not be an alkali-soluble polymer, and may be an alkali-soluble polymer. The inorganic filler is preferably co-sinterable (cofire) with an inorganic filler used in the photosensitive insulating paste.

Next, a photosensitive conductive paste is screen-printed on the outer insulating layer formed in the above manner, and then dried, followed by selective exposure and development, thereby forming a layer 1 conductor layer (coil pattern).

Next, a photosensitive insulating paste is screen-printed (full-surface printing) on the formed 1 st conductor layer (coil pattern) and its periphery to form a 1 st photosensitive insulating paste layer (insulating layer).

Then, the photosensitive insulating paste is selectively exposed and developed to form a through hole at a predetermined position.

Then, a photosensitive conductive paste was printed over the entire surface by screen printing and dried. Then, the conductor layer (coil pattern) of the 2 nd layer is formed by selectively performing exposure and development.

Further, a photosensitive insulating paste was printed on the conductor layer and the periphery thereof, and a through hole was formed, thereby forming a 2 nd insulating layer.

The same method as described above is repeated to form a photosensitive insulating paste layer (insulating layer) having through holes at predetermined positions and a coil pattern (conductor layer) until a predetermined number of layers are formed.

Next, application of a photosensitive insulating paste by screen printing was further repeated to form an external insulating layer. The outer insulating layer is an outer insulating layer located outside the coil conductor layer portion.

The mother laminate was obtained through the above steps.

Next, the mother laminate is cut into a plurality of unfired laminates by dicing or the like.

Then, the unfired laminate is fired at 850 to 950 ℃ to obtain a laminate 12.

Then, the laminated body 12 is subjected to barrel polishing and plating as necessary.

Next, the external electrode 30 is formed. That is, on the surface of the laminate 12, the exposed portion of the lead electrode 22a exposed from the 1 st end face 12a is coated with a conductive paste for external electrodes containing a glass component and a metal by a method such as dipping, and then sintered to form the 1 st external electrode 30 a. Similarly, the 2 nd external electrode 30b is formed by applying a conductive paste for external electrodes containing a glass component and a metal to the exposed portion of the lead electrode 22b exposed from the 2 nd end face 12b of the laminate 12 by a method such as dipping and then sintering the applied conductive paste to form the 2 nd external electrode 30 b.

The coil conductor layer 24 (internal electrode layer) and the external electrode 30 may be fired simultaneously.

The coil electronic component 10 is manufactured through the above steps.

According to the coil electronic component 10 shown in fig. 1, if the average thickness of the side gap portions 16a, 16b of the coil electronic component 10 is 5 μm to 30 μm, the coil conductor layer 24 (internal electrode layer) can be widely arranged inside the electronic component, and the mechanical strength can be maintained. Therefore, the Q value, which is a characteristic of the coil electronic component 10, can be improved.

In addition, according to the coil electronic component 10 shown in fig. 1, if the void ratio is 5% or less, the mechanical strength of the coil electronic component 10 can be further improved.

Further, according to the coil electronic component 10 shown in fig. 1, if the conditions that the content of the 1 st inorganic filler (alumina) having a large refractive index is in the range of 5 vol% to 20 vol% and the total content of the 1 st inorganic filler and the 2 nd inorganic filler is 25 vol% to 40 vol% are satisfied, when the photosensitive insulating paste is used for the insulating layer of the electronic component, high light transmittance is provided before firing, and therefore, high resolution can be satisfied, and light transmittance is suppressed after firing, and therefore, the same color between the portion on the internal electrode layer and the portion of the side gap portion on the surface of the coil electronic component after firing can be maintained. In addition, since the sintering of the insulating layer proceeds sufficiently, the ceramic material can exhibit mechanical strength.

5. Examples of the experiments

Next, in order to confirm the effects of the photosensitive insulating paste of the present invention, coil electronic components were manufactured using the photosensitive insulating paste, and experiments were performed to evaluate the appearance of the coil electronic components, evaluate the crack occurrence load, evaluate the density inside the coil electronic components, and measure the resolution (aspect ratio).

(1) Specification of the sample

The specifications of the samples used in this experiment are as follows.

For the size (design value) of the coil electronic component, the L size is 0.4mm, the W size is 0.2mm, and the T size is 0.2 mm.

Composition of the insulating layer: the glass (glass frit), the 1 st inorganic filler and the 2 nd inorganic filler were in the composition ratios shown in table 1. Note that the glass (glass frit) is borosilicate glass, the 1 st inorganic filler is alumina, and the 2 nd inorganic filler is quartz.

Size of side gap: 17.5 μm. The cross section of the sample was exposed by Destructive Physical Analysis (DPA), and the side gap portion was measured with a microscope. The number of samples was 5.

Refractive index of inorganic filler: 1 inorganic filler: 1.8

Inorganic filler of No. 2: 1.5

The photosensitive insulating paste was prepared by mixing the following raw materials and thoroughly mixing them with 3 rolls.

Namely, the photosensitive insulating paste is prepared from the following raw materials:

(a) a glass frit (borosilicate glass),

(b) a 1 st inorganic filler (alumina) and a 2 nd inorganic filler (quartz),

(c) alkali-soluble polymers (acrylic polymers having carboxyl groups in the side chains),

(d) a photosensitive monomer (polyfunctional acrylate: dipentaerythritol monohydroxypentaacrylate),

(e) a photopolymerization initiator (acetophenone-based compound),

(f) Solvent (1- (2-methoxy-2-methylethoxy) -2-propanol), and

(g) organic dyes (azo compounds).

The average particle size of the glass frit was 1.0. mu.m, the average particle size of the 1 st inorganic filler was 0.5. mu.m, and the average particle size of the 2 nd inorganic filler was 1.0. mu.m.

(2) Method for measuring refractive index of inorganic filler

The refractive index was measured by a compositional analysis method. As a cross section of the sample, the WT cross section was polished to 1/2L to expose the cross section, and composition analysis of the glass portion, the 1 st inorganic filler portion, and the 2 nd inorganic filler portion was performed using EDX. From the results, the composition ratio was determined, and the refractive index was deduced.

(3) Observation of color of surface of coil electronic component

The color of the surface of the coil electronic component as a sample was observed with a microscope. Specifically, the same color between the portions on the coil conductor layers (internal electrode layers) on the surface of the coil electronic component and the portions in the side gap portions was observed by visual observation. On the surface of the coil electronic component, the color of the internal electrode layer was visible through the portion on the internal electrode layer on the surface of the coil electronic component, and when the color of the portion on the internal electrode layer on the surface of the coil electronic component was different from that of the portion in the side gap portion, the evaluation was x, and the other evaluation was o.

(4) Evaluation of crack occurrence load

As shown in fig. 4, each sample (coil electronic component 10) was fixed to the alumina substrate 50 with the side surface facing downward with an adhesive 52. The adhesive 52 is an instant adhesive. Next, the alumina substrate 50 to which the samples were bonded was fixed to an evaluation table of a nano indenter, and a test load (p) -displacement (h) graph when the indenter 54 was pressed one by one was obtained for each sample. From the obtained test load (p) -displacement (h) data, the contact rigidity (S ═ dp/dh) at the time of load increase was calculated, and a graph of the contact rigidity (S) -test load (p) was prepared. Among the peaks showing a decrease in contact rigidity in the created graph, the peak at the lowest load was determined as the crack that occurred first in the chip, and the load at that time was defined as the "crack occurrence load". Regarding the crack occurrence load, 30N or more was determined to be good, and 74N or more was determined to be further good.

The apparatus and measurement conditions for the nano-indenter are as follows.

Equipment: nanometer pressure head

ENT-1100 a (manufactured by ELIONIX corporation)

Test load: 100gf

Step length: 20msec

(5) Method for evaluating resolution (aspect ratio)

A paste was printed by screen printing to a thickness of 20 μm, dried in a safety oven, exposed through a photomask having openings of various sizes, and developed with an alkaline aqueous solution to form a wiring pattern. The width and thickness of a pattern that can be created without residue or pattern deletion are measured, and the aspect ratio (thickness/width) is calculated.

(6) Evaluation of Density of interior of laminate

As a cross section of the sample, the WT cross section was polished to 1/2L to expose the cross section. Then, the image obtained by observing the cross section with SEM was subjected to a 2-valued process for brightness, and the areas of the sintered laminate portion and the voids left by non-sintering were calculated. Then, the ratio of the area of the voids to the entire laminate was defined as the porosity. The range of the void ratio of 5% to 10% was judged as good and indicated by ". smallcircle", and the range of 5% or less was judged as more good and indicated by ". circleincircle". Fig. 5(a) shows a state of the insulating layer having a porosity of more than 5%, and fig. 5 (b) shows a state of the insulating layer having a porosity of 5% or less.

The results of "observation of color of coil electronic component surface", "evaluation of crack occurrence load", "resolution (aspect ratio)" and "density inside laminate" of the samples of each sample number are shown in table 1.

(7) Evaluation results

As a result of observing the color of the surface of the coil electronic component, as shown in table 1, in the sample of sample No. 7, since the content of the 1 st inorganic filler (alumina) having a large refractive index was small, the coil conductor layer (internal electrode layer) was transparent, but when the thickness of the side gap portion was 30 μm, the identity of the color and the suppression of light transmission were confirmed.

On the other hand, since the samples of sample nos. 1 to 6, 8 and 9 were contained in the range of 5 to 24 vol% of the content of the 1 st inorganic filler (alumina) having a large refractive index, it was confirmed that the color of the portion on the coil conductor layer (internal electrode layer) on the surface of the coil electronic component and the color of the portion in the side gap portion were the same.

Thus, it is suggested that the light transmittance of the insulating layer after firing can be adjusted by adjusting the contents of the 1 st inorganic filler and the 2 nd inorganic filler.

As a result of evaluating the crack occurrence load, as shown in table 1, it was confirmed that the sample of sample No. 7 had a small content of the 1 st inorganic filler (alumina), but had a large content of the 2 nd inorganic filler, and thus coil electronic components having strength necessary for performance could be obtained. Further, it was confirmed that in the sample of sample No. 8, since the total content of the 1 st inorganic filler (alumina) and the 2 nd inorganic filler (quartz) was too large, the content of the glass frit was small, and the composition was difficult to sinter, but a coil electronic component having strength required for performance was obtained. Further, it was confirmed that in the sample of sample No. 9, the total content of the 1 st inorganic filler (alumina) and the 2 nd inorganic filler (quartz) was small, and therefore, the content of the glass frit was large, and thus sintering was possible, but the inorganic filler component was small, and the progress of cracks was inhibited to the minimum, and a coil electronic component having strength necessary for performance was obtained.

On the other hand, it was confirmed that the samples of sample nos. 1 to 6 contained the 1 st inorganic filler (alumina) having a large refractive index in the range of 5 to 24 vol% and the total content of the 1 st inorganic filler (alumina) and the 2 nd inorganic filler (quartz) in the range of 25 to 40 vol%, and thus coil electronic components having a further excellent strength were obtained.

As shown in table 1, it was confirmed that the samples of sample nos. 1 to 9 contained the 1 st inorganic filler (alumina) and the 2 nd inorganic filler (quartz) in appropriate ranges, and thus wiring patterns having an aspect ratio of 0.5 or more were obtained.

It was confirmed that the samples of sample nos. 1 to 5 and 7 to 9 had a more preferable aspect ratio of 1.0 or more since the content of the 1 st inorganic filler (alumina) was small.

As shown in table 1, the results of evaluation of the density of the interior of the laminate confirmed that the density was good for any of sample No. 1 to sample No. 9.

As described above, the embodiments of the present invention are disclosed in the above description, but the present invention is not limited thereto.

That is, the mechanism, shape, material, number, position, arrangement, and the like of the above-described embodiments may be variously modified without departing from the technical idea and target scope of the present invention, and these are included in the present invention.

For example, in the above embodiment, the coil is configured by laminating a plurality of coil conductor layers having a winding number of less than 1 cycle, but the winding number of the coil conductor layers may be 1 cycle or more. That is, the coil conductor layer may have a planar spiral shape.

In the above embodiment, the winding axis direction of the coil is substantially the same direction as the z axis, but the winding axis direction of the coil may be parallel to the 1 st main surface.

Further, in the above embodiment, the external electrodes are disposed on both main surfaces and both side surfaces extending from both end surfaces, but the present invention is not limited to this, and the 1 st external electrode may be formed to extend from the 1 st end surface to the 2 nd main surface and cover a part of each of the 1 st end surface and the 2 nd main surface, and the 2 nd external electrode may be formed to extend from the 2 nd end surface to the 2 nd main surface and cover a part of each of the 2 nd end surface and the 2 nd main surface.