JP4730805B2 - Thick film chip capacitor and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thick film chip capacitor and a method for manufacturing the same, and more particularly to an improvement for obtaining various capacitances accurately and at low cost.
[0002]
[Prior art]
A conventional thick film chip capacitor is shown in FIG. 8 as a cross-sectional view thereof and as shown in FIG. 9 as a manufacturing process thereof, on the alumina ceramic substrate 1 (FIG. 9A). The formed surface capacitive electrode film layer 3 (FIG. 9B) composed of a pair of thick films, the dielectric film layer 6 (FIG. 9C) formed between the surface capacitive electrode film layers 3, The main part is composed of a protective film layer 7 (FIG. 9D) made of overcoat glass covering the dielectric film layer 6. This means that the number of manufacturing steps and circuit components can be reduced as compared with a thick film chip capacitor having a so-called multilayer structure in which a lower electrode, a dielectric film layer, and an upper electrode are formed on a ceramic substrate. Excellent in terms.
[0003]
[Problems to be solved by the invention]
However, in the conventional thick film chip capacitor, since the capacitive electrode film layers 3 that are separated from each other with the gap 5 interposed therebetween are formed by thick film printing, the shape of the gap 5 depends on the screen printing accuracy. Thus, it was impossible to form the gap 5 with high accuracy. For this reason, it is difficult to form a gap portion 5 having a complicated shape or a narrow width. Specifically, the width of the gap 5 and the meandering width by screen printing are limited to about 100 μm, and if it is narrower than this, printing defects such as short-circuiting due to creaking and sagging have occurred.
[0004]
In order to obtain capacitors having various capacities, it is necessary to adjust the capacitance value by appropriately changing the interval, number, or shape of the gap 5. Therefore, a plurality of screen masks used for forming the gap portion 5 are required, which increases the manufacturing cost.
[0005]
Furthermore, there has been a problem that the color factor contained in the protective film layer 7 covering the dielectric film layer 6 reduces the Q value (Quality factor) of the capacitor.
[0006]
The present invention has been made in order to solve the above-described conventional problems. The object of the present invention is to achieve a desired capacitance with high accuracy, and at a low cost even with a small amount of capacitors having various capacitances. The object is to provide a thick film chip capacitor that can be manufactured and is suitable for production of a small variety of products.
[0007]
Another object of the present invention is to provide a thick film chip capacitor that can be manufactured without using various screen masks in addition to the above object.
[0008]
Still another object of the present invention is to provide a thick film chip capacitor that does not deteriorate its performance due to the inclusion of the protective film layer in addition to the above object.
[0009]
Still another object of the present invention is to provide a method for manufacturing a thick film chip capacitor in which existing equipment for element formation by conventional thick film printing can be used as it is in addition to the above object.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a pair of surface capacitive electrode film layers opposed to each other with at least one gap formed on the surface of an insulating dielectric substrate by laser light irradiation, and the gap at least a plurality of layers of the dielectric layer to fill between it and the gap covering, said dielectric film layer and a protective layer covering at least a portion of the surface capacitive electrode film layer, formed by the forming capacitor a structure, as well as a transparent or semi-transparent by glass paste containing no fit adhesive color pigment to prevent deterioration in performance of the capacitor the protective layer, the transparent or a back surface of the insulating dielectric substrate a different color from that of the dielectric film layer visible through the protective layer of semi-transparent, thick film chip capacitor is provided which is characterized in that the formation of the colored insulating film layer.
As a result, a desired capacitance can be realized with high accuracy, and capacitors having various capacitances can be provided at a low cost.
[0011]
Further, in the thick film chip capacitor, the shape of the gap is linear, meandering, or a combination thereof, and further, the electrode film layers on both the front and back surfaces of the dielectric dielectric substrate, It is also preferable that the gap, the dielectric film layer, and the protective film layer are formed.
[0012]
A method of manufacturing a thick film chip capacitor of the present invention, a laser forming a surface capacitor electrode film layer on the insulating surface of the dielectric substrate, one or more of the gap portion even the surface capacitor electrode film layer small without A step of forming a pair of surface capacitive electrode film layers facing each other by dividing into a linear shape, a meandering shape, or a combination thereof by light irradiation; and a dielectric covering the gap portion and filling the gap portion a step of a plurality of layers forming the film layer, and forming the dielectric film layer has covering, and a transparent or translucent protective film glass paste containing no coloring pigment to prevent the deterioration of the performance of the capacitor, by further on the back surface of the insulating dielectric substrate and a step of forming the dielectric film layer insulating film layer colored a different color from the color of the visible through the protective film layer of the transparent or semi-transparent, Capacitor front and back And it shall be characterized in that to be able to determine.
As a result, the thick film chip capacitor of the present invention can be manufactured using the existing equipment for element formation by conventional thick film printing as it is.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a thick film chip capacitor according to the present invention will be described below with reference to the accompanying drawings.
[0014]
(First embodiment)
FIG. 1 is a cross-sectional view in the longitudinal direction of the substrate showing the basic configuration of the thick film chip capacitor of the first embodiment of the present invention. As shown in this figure, the thick film chip capacitor A has a basic configuration including an insulating dielectric substrate 1, a surface capacitive electrode film layer 3, a gap portion 5, a dielectric film layer 6, and a protective film layer 7. is doing.
[0015]
That is, the surface capacitive electrode film layer 3 is formed on the insulating dielectric substrate 1 so as to face each other with at least one gap portion 5 interposed therebetween. On the surface capacitive electrode film layer 3, at least one dielectric film layer 6 covering and filling the gap portion 5 is formed. A protective film layer 7 is formed so as to cover at least part of the dielectric film layer 6 and the surface capacitive electrode film layer 3.
[0016]
Hereinafter, the manufacturing process of the thick film chip capacitor A will be described with reference to FIGS. Here, FIG. 2 is a plan view for explaining the manufacturing process, and FIG. 3 is a flowchart of the manufacturing process.
[0017]
First, a silver-based back electrode film layer 2 is formed on the back surface of an insulating dielectric substrate 1 such as alumina ceramic shown in FIG. 2A by screen printing / firing as shown in FIG. Step 301).
[0018]
Next, as shown in FIG. 2C, a silver-palladium-based surface capacitive electrode film layer 3 is formed on the surface of the insulating dielectric substrate 1 by screen printing / firing (step 302).
[0019]
Next, as shown in FIG. 2D, the back surface is printed and baked with a glass paste colored in a hue different from the color of the dielectric film layer 6 between the back electrodes on the back surface of the insulating dielectric substrate 1. The insulating film layer 4 is formed (step 303).
[0020]
Next, as shown in FIG. 2 (e), the surface capacitive electrode film layer 3 is divided into a substantially central portion of the surface capacitive electrode film layer 3 so as to be divided to a desired capacitance value. 5 is formed by laser beam irradiation (step 304). Here, one or more gaps 5 are formed according to a desired capacitance value, and are formed in a linear or meandering shape as necessary.
[0021]
Next, as shown in FIG. 2 (f), printing of the glass paste containing strontium titanate so as to cover at least part of the gap 5 and the surface capacitive electrode film layer 3 and fill the gap 5 inside. The dielectric film layer 6 is formed by firing (step 305). Here, the dielectric film layer 6 is formed by printing at least one layer or more in accordance with a desired capacitance value so as to have a thickness enough to saturate the capacitance value.
[0022]
Next, as shown in FIG. 2 (g), a transparent or translucent protective film layer 7 is formed by printing and baking a lead borosilicate glass paste so as to cover the dielectric film layer 6 (step 306). .
[0023]
Next, as shown in FIG. 2 (h), the insulating dielectric substrate 1 is divided into a rod-like substrate (step 307), and the surface capacitive electrode film layer 3 and the back surface are formed by applying, baking or curing a conductive material. An end face electrode 8 that conducts to the electrode film layer 2 is formed (step 308), and the rod-shaped substrate is divided into individual substrates (step 309).
[0024]
And finally, as shown in FIG. 1, the plating layer 9 is formed by performing nickel plating and solder or tin plating on the exposed portions of the back electrode film layer 2, the surface capacitor electrode film 3, and the end face electrode 8 ( Step 310), the thick film chip capacitor A of the present embodiment is completed.
[0025]
(Second Embodiment)
FIG. 4 is a schematic cross-sectional view showing the basic configuration of the thick film chip capacitor according to the second embodiment of the present invention. The basic elements constituting the thick film chip capacitor A of this embodiment are almost the same as those of the first embodiment, but the capacitive electrode film layer 3b, the gap 5b, the dielectric film are also formed on the back surface of the insulating dielectric substrate 1. The difference is that the layer 6b and the protective film layer 7b are formed.
[0026]
That is, the surface capacitive electrode film layer 3a and the back capacitive electrode film layer 3b are formed on the front surface and the back surface of the insulating dielectric substrate 1 so as to face each other with at least one gap portion 5a, 5b interposed therebetween. . Further, at least one or more dielectric film layers 6a and 6b covering and filling the gaps 5a and 5b are formed on the front and back surface capacitive electrode film layers 3a and 3b. Further, protective film layers 7a and 7b are formed so as to cover at least part of the dielectric film layers 6a and 6b and the surface capacitive electrode film layers 3a and 3b, respectively.
[0027]
Hereinafter, the manufacturing process of the thick film chip capacitor A will be described with reference to FIGS. Here, FIG. 5 is a flowchart of the manufacturing process.
[0028]
First, a silver-palladium-based surface capacitive electrode film layer 3a and a back capacitive electrode film layer 3b are formed on the front and back surfaces of an insulating dielectric substrate 1 such as alumina ceramic by screen printing and firing (steps 501 and 502).
[0029]
Next, a desired capacitance value is obtained so as to divide the surface capacitive electrode film layer 3a and the back capacitive electrode film layer 3b at substantially the center of the surface capacitive electrode film layer 3a and the back capacitive electrode film layer 3b. The combined gaps 5a and 5b are formed by laser light irradiation (step 503). Here, one or more gap portions 5a and 5b are formed according to a desired capacitance value, and are formed in a linear or meandering shape as necessary. FIG. 6 schematically shows a perspective view of the thick film chip capacitor A in which the meandering gap 5a is formed on the front surface and the linear gap 5b is formed on the back surface.
[0030]
Next, at least a part of the gap 5a and the surface capacitive electrode film layer 3a and at least a part of the gap 5b and the back capacitive electrode film layer 3b are respectively covered, and the gaps 5a and 5b are filled, respectively. Then, the dielectric film layers 6a and 6b are formed by printing and baking the glass paste containing strontium titanate (step 504).
Here, the dielectric film layers 6a and 6b are printed so that the number of layers is appropriately overlapped by at least one or more in accordance with a desired capacitance value in order to give the thickness that the capacitance value is saturated.
[0031]
Next, transparent or semi-transparent protective film layers 7a and 7b are formed by printing and baking a borosilicate glass paste so as to cover the dielectric film layers 6a and 6b, respectively (step 505).
[0032]
Next, the insulating dielectric substrate 1 is divided into a rod-shaped substrate (step 506), and an end face that conducts the surface capacitive electrode film layer 3a and the back capacitive electrode film layer 3b by applying, baking or curing a conductive material. The electrode 8 is formed (step 507), and the rod-shaped substrate is divided into individual substrates (step 508).
[0033]
Finally, nickel plating and solder or tin plating are applied to the exposed portions of the surface capacitive electrode film layer 3a, the back capacitive electrode film layer 3b, and the end face electrode 8 to form a plating layer 9 (step 509), The thick film chip capacitor A of the embodiment is completed.
[0034]
(Features of each embodiment)
The thick film chip capacitors of the above embodiments are excellent in the following points.
That is, a plurality of screen masks conventionally required to obtain a desired capacitance value is not necessary, and a desired capacitance value can be obtained by changing the shape of laser light irradiation. For this reason, cost reduction can be realized, and it is possible to cope with small-lot and multi-product production.
[0035]
In addition, since gaps are formed by laser light to obtain a desired capacitance value, conventional equipment used for manufacturing chip resistors can be used as it is, and work can be performed in the state of a collective substrate. The work efficiency is good and the cost can be reduced.
[0036]
In addition, the gap 5 formed by laser light irradiation can be narrower than the conventional one and has good dimensional accuracy, so that an accurate capacitance value can be obtained.
This also increases the capacitance value by forming the gaps in a high-density meandering shape, thereby realizing a reduction in the thickness of the thick film chip capacitor. 7A to 7D show examples of formation when the gap 5 has a meandering shape.
[0037]
Further, since one or more gap portions 5 are provided, a series capacitor can be equivalently obtained on the thick film chip capacitor, so that the range of the capacitance value can be expanded in the direction of decreasing capacitance. FIG. 7E shows an example in which two linear gaps 5 are formed.
[0038]
In addition, by forming at least one dielectric film layer so that the capacitance value is saturated, the variation in the capacitance value due to the thickness of the electrostatic film layer is reduced, and at the design stage. The variation of the capacitance value of the capacitor is reduced, and it becomes easy to set the capacitance value with high accuracy.
[0039]
In addition, since the protective film layer is transparent or semi-transparent without containing a color pigment, it is possible to prevent the Q value of the thick film chip capacitor from being lowered.
[0040]
In the first embodiment, since the insulating film layer colored so that the front and back sides can be distinguished is formed on the back surface of the insulating dielectric substrate, the surface color of the thick film chip capacitor is transparent or translucent. Through the protective film layer, it becomes a milky white dielectric film layer color, and it is possible to eliminate the difficulty of discriminating the front and back surfaces because it approximates or matches the color of the insulating dielectric substrate.
[0041]
Furthermore, in the second embodiment, since the elements are formed on the front and back surfaces, a capacitor in parallel with one thick film chip capacitor can be formed, and the capacitance value range can be expanded in the direction of larger capacitance. .
[0042]
(Other)
In each of the above embodiments, the front surface (back surface) capacitive electrode film layer is formed by screen printing / firing of a silver-palladium material, but the present invention is not limited to this. For example, a paste made of a conductive material containing silver, copper, or the like may be formed by printing, coating, baking, curing, or the like.
Further, the dielectric film layer is not limited to the glass paste containing strontium titanate.
[0043]
【Example】
In order to confirm the effectiveness of the thick film chip capacitor of the present invention, the thick film chip capacitor shown in the first embodiment was prepared in various sizes of 0.1, 0.2, 0.3, 0.4, and 0.5 pF. And the accuracy was examined. The gap was formed by irradiation with a YAG laser used for resistance value trimming of the resistor. Its width is about 30 μm. The outer dimension is 1005 size.
As a result, it was found that each of the above five types of thick film chip capacitors had a capacitance value of 10%. Thus, according to the present invention, it can be said that a desired capacitance can be realized with high accuracy.
[0044]
【The invention's effect】
As described above, the thick film chip capacitor of the present invention forms gaps by irradiating the capacitive electrode film formed by thick film printing with laser light, and appropriately changes the number and shape of the gaps. A desired capacitance value is obtained. This eliminates the need for various screen masks and multiple dielectric materials, suppresses variations in capacitance values during the manufacturing process, and manufactures highly accurate thick film chip capacitors with various capacities at a low cost. And by extension, it can be used for small-lot, multi-product production.
Further, the chip resistor manufacturing equipment can be used as it is by forming an element by thick film printing and forming a gap by laser light irradiation.
Furthermore, by forming a transparent or translucent protective film layer, it is possible to prevent deterioration of the performance of the capacitor due to the colored inclusions.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view (substrate longitudinal direction) schematically showing a thick film chip capacitor according to a first embodiment of the present invention.
2 is a plan view for explaining a manufacturing process for the thick film chip capacitor shown in FIG. 1; FIG.
FIG. 3 is a flowchart for explaining a manufacturing process of the thick film chip capacitor shown in FIG. 1;
FIG. 4 is a cross-sectional view (substrate longitudinal direction) schematically showing a thick film chip capacitor according to a second embodiment of the present invention.
FIG. 5 is a flowchart for explaining a manufacturing process of the thick film chip capacitor shown in FIG. 4;
6 is a perspective view schematically showing the thick film chip capacitor shown in FIG. 4; FIG.
7 is a plan view showing another example of the gap shape of the thick film chip capacitor shown in FIG. 1 or FIG. 4. When (a) to (d) are meandering shapes, two are shown in (e). The case where it is formed will be described.
FIG. 8 is a cross-sectional view (substrate longitudinal direction) schematically showing a conventional thick film chip capacitor.
FIG. 9 is a plan view for explaining a manufacturing process for the thick film chip capacitor shown in FIG. 8;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Insulating dielectric substrate 2 Back surface electrode film layer 3 (3a) Surface capacitive electrode film layer 3b Back surface capacitive electrode film layer 4 Back surface insulating film layer 5 (5a, 5b) Gap part 6 (6a, 6b) Dielectric film layer 7 (7a, 7b) Protective film layer 8 End face electrode 9 Plating layer A Thick film chip capacitor

Claims (3)

A pair of surface capacitive electrode film layers opposed to each other across at least one gap formed by laser light irradiation on the surface of the insulating dielectric substrate; and at least filling the gap between the gaps A capacitor structure formed by forming a plurality of dielectric film layers and a protective film layer covering at least a part of the dielectric film layer and the surface capacitance electrode film layer,
As well as to the protective layer a transparent or semi-transparent by glass paste containing no fit adhesive color pigment to prevent deterioration in performance of the capacitor, the transparent or semi-transparent protective layer on the back surface of the insulating dielectric substrate A thick film chip capacitor, wherein an insulating film layer colored in a color different from the dielectric film layer seen through is formed.   2. The thick film chip capacitor according to claim 1, wherein the gap portion has a linear shape, a meandering shape, or a combination thereof. Forming a surface capacitor electrode film layer on the insulating surface of the dielectric substrate, the surface capacitor electrode film layer less without even one or more of the gap straight by irradiation of laser light, serpentine, or a combination thereof Forming a pair of opposing surface capacitance electrode film layers divided into shapes, forming a plurality of dielectric film layers covering the gap and filling the gap, and the dielectric film not covering layer, and forming a transparent or translucent protective film glass paste containing no coloring pigment to prevent the deterioration of the performance of the capacitor, the further back side of the insulating dielectric substrate wherein a transparent or by including the step of forming an insulating film layer colored a different color from the color of the dielectric layer visible through the protective film layer of semi-transparent, characterized in that to be able to determine the front and back of the capacitor Thick film chip Method of manufacturing a capacitor.

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