JPH02296312A - Electronic component and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain electronic components high in reliability with small defective sections by varying the softening temperatures of the materials of insulating layers formed on both sides of a substrate. CONSTITUTION:The softening temperatures of insulating layer materials vary between insulating layers 30 and 31 formed on both sides of a porcelain substrate 11, and on the insulating layer 30 high in softening temperature, application of insulating layer material, baking at a temperature near the softening temperature, and cooling are done in advance, and then on the insulating layer 31 in softening temperature, application of insulating layer material, baking at a temperature near the softening temperature, and cooling are done similarly. For this reason, in a process of forming the insulating layer 31 low in softening temperature, the insulating layer 30 high in softening temperature being formed already never begins to fuse. Accordingly, the insulating layer material can be hardened again without demolishing the shape of the insulating layer 30, and the thickness of the insulating layer can be taken larger, and defective parts such as pin holes, an extremely thin part, etc., decrease. Hereby, the reliability of electronic components can be improved.

Description

[Detailed Description of the Invention] The present invention relates to electronic components and methods for manufacturing the same, and mainly relates to surface mounting (SMT) on printed circuit boards of electronic circuits including semiconductor devices.
technology).

Electronic components such as capacitors, varistors, and capacitive varistors are manufactured by forming counter electrodes such as silver on both sides of a ceramic substrate with good insulation, and an insulating layer on the top of these counter electrodes. The structure is The specific structure of such an electronic component is as shown in FIGS. 4 to 6, in which opposing electrodes 12 are formed on one side A and the other side B of a ceramic substrate 11, respectively.
End electrodes 14 are formed on the outer surfaces of these counter electrodes 12 to connect these counter electrodes 12 with external electrodes, and Ni plating layers 15 are formed on the outer surfaces of these end electrodes 14.
, Sn plating (also referred to as solder plating), and layer 16 are laminated. An insulating layer 17 is formed on both sides of the ceramic substrate 11 from above the counter electrode 12 to insulate the upper and lower counter electrodes 12 and 12 and the left and right end electrodes 14 and 14.

The method for manufacturing such an electronic component is the same as that for a single-plate capacitor up to the step of printing and firing the counter electrode Y2 on the ceramic substrate 11. Further, the step of forming the insulating layer 17 is as follows:
An insulating material such as glass powder is made into a paste, and this paste-like insulating material is applied to one side of the ceramic substrate 1.1 by screen printing or the like, and after drying, the insulating material is applied to the other side in the same way. After drying (. After this, place the porcelain substrate 11 on a setter, and set this setter in a firing furnace.
~900° C.) to heat and melt the insulating material, cool it, and re-harden it to form insulating layers 17 and 17 on both surfaces of the ceramic substrate 11 at the same time. Thereafter, end electrodes 14 made of silver or the like are formed, and the entire electronic component is immersed in a plating solution so that the end electrodes 14 are not plated.

The two layers of plating 15 and 16 are for preventing defects such as so-called silver holes caused by melting of the silver electrode when connecting an external electrode to the end electrode 14. If defects such as pin holes or extremely thin portions occur in the insulating layer 17, the plating solution penetrates into the grain boundary layer in the ceramic substrate 11 from these defective portions, causing erosion of the grain boundary insulating layer, a decrease in insulation resistance, etc. This caused a reduction in the reliability of electronic components, such as shortening product life. Therefore, in order to maintain the reliability of electronic components, it is important to prevent the plating liquid from penetrating into the 1IFL substrate 11 from the defective portions of the insulating layer 17. For this purpose, in the past, the insulating layer 17 was made thicker, and the substrate end faces 13a and 13b were
An insulating layer was formed on the

Problems to be Solved by the Invention However, the upper and lower insulating layers 17.
In the method of forming the insulating layer 17, it was difficult to make the insulating layer 17 thick, so pinholes and extremely thin portions were likely to occur. For this reason, the plating liquid penetrates into the ceramic substrate 11 from these defective parts, causing a decrease in the reliability of the electronic component.

In addition, in the conventional manufacturing method, the insulating layers 17 and 17 on both sides of the porcelain base 111ij11 were formed at the same time.
The insulating material melts and adheres to the setter and the inner wall of the furnace, causing deformation and uneven thickness of the insulating layer 17, resulting in a decrease in product yield.

Furthermore, in the conventional manufacturing process of the insulating layer 17 described above, an insulating layer is not formed on the substrate end faces 13a and 1.3b, and it is possible that the plating liquid may penetrate into the ceramic substrate 11 from these parts. , it is desirable to form an insulating layer also on the substrate end faces 13a and L3b. However, in the method of forming the insulating layer 17 by applying the insulating layer material by means such as screen printing, when the insulating layer is also formed on the substrate end surfaces 13a and 13b, the insulating layer material is applied to the substrate end surfaces 13a and 13b. There is a problem in that additional steps are required and the manufacturing process becomes complicated.

The present invention has been made in view of the above-mentioned problems, and the insulating layer can be formed thickly, so there are fewer defects, and therefore the reliability is high.In addition, the insulating layer material does not melt out during the formation of the insulating layer. The purpose of this invention is to provide an electronic component and its manufacturing method that does not reduce product yield, and furthermore, to provide a method that allows an insulating layer to be formed on the end surface of a substrate without increasing the number of steps.

-Illr' To achieve the above object, the present invention provides a counter electrode formed on a portion including one surface of a substrate and a portion including the other surface, and an end surface electrode connected to the counter electrode. and an insulating layer formed on both sides of the substrate for insulating between these opposing electrodes, the electronic component is characterized in that the materials of the insulating layers formed on both sides of the substrate have different softening temperatures.

Further, in the method for manufacturing an electronic component, a counter electrode is formed on a portion including one surface of the substrate and a portion including the other surface, respectively;
After that, an insulating layer material having a high softening temperature is applied to one surface of the substrate, and the material is fired at a temperature near the softening temperature, and then cooled.
Next, the method is characterized in that it includes a step of applying an insulating layer material having a low softening temperature to the other surface of the substrate, firing it at a temperature close to its softening temperature, and then cooling it.

Further, in the above method for manufacturing an electronic component, one or both of the insulating layer materials is molded to be wider than the substrate, and the molded body and the substrate are overlapped and fired and cooled to form an insulating layer on the end surface of the substrate. It is characterized by

Effects According to the above structure and method, the softening temperatures of the insulating layer materials formed on both sides of the substrate are different, and the insulating layer material having a high softening temperature is applied, fired at a temperature near the softening temperature, and then cooled. Next, an insulating layer material with a low softening temperature is applied to the other surface of the substrate, fired at a temperature near the softening temperature, and then cooled. The formed insulating layer with a high softening temperature will not melt. Therefore, the insulating layer material can be re-hardened without changing the shape of the insulating layer, making it possible to increase the thickness of the insulating layer and almost eliminate defects such as pinholes and extremely thin areas. It disappears.

Further, according to the above manufacturing method, when forming an insulating layer on the end surface of a substrate, one or both of the insulating layer materials is molded to be wider than the substrate, and the molded body and the substrate are overlapped and fired. The portion of the molded body that protrudes from the substrate due to overlapping will be melted by firing and will cover the end surface of the substrate, making it possible to form an insulating layer on the end surface of the substrate without any special process.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Below, embodiments of electronic components according to the present invention will be described based on the drawings, and in this embodiment, a capacitor will be described as an example. It should be noted that FIG. 4 used in the explanation of the conventional example is used as the plan view of this embodiment, and parts having the same structure as the conventional example are given the same reference numerals (=l).

In FIGS. 1 and 4, the upper surface A of the ceramic substrate 11
Opposing electrodes 12 are formed on J3 and the lower surface B, respectively, and end electrodes 14 are formed on the outer surfaces of the side surfaces of the counter electrodes 12.12 to connect the counter electrodes 12 and external electrodes, and the left and right end electrodes 14. An N1 plating layer 15 and a Sn plating (also referred to as solder plating) layer 16 are laminated. Insulating layers 30 and 31 for insulating between the upper and lower opposing electrodes 12 and 12 and the left and right end face electrodes 14 and 14 are formed on both sides A-B of this unloader substrate 11.

Glass powder is used as the material for these insulating layers 30 and 31, and each glass powder has a different softening temperature.

Next, a method for manufacturing the capacitor according to this example will be explained.

First, an electrode material such as silver is coated by screen printing on a porcelain body with slits formed therein, and then fired to form the counter electrode 12. After that, cutting is performed at the slit portion to form one capacitor. Cut the ceramic substrate 11 into small pieces. After this, porcelain board 1
Silver paste, which is an electrode material, is applied and fired on the end of the electrode 1 to form an end electrode 14.

Next, a vehicle, which is a binder, is added to two types of insulating layer materials with different softening temperatures to form a paste.
Create insulation paste.

Then, an insulating paste with a high softening temperature is applied to one side A side of the ceramic substrate 11 by screen printing or the like, and after drying, the ceramic substrate 11 is placed on a setter with this side facing up, and the setter is set in a firing furnace. Then, the insulating material is heated to a temperature close to the softening temperature of the insulating material to melt it, and then cooled and hardened again to form the insulating layer 30. Next, an insulating paste with a low softening temperature is applied and dried on the other surface B side of the ceramic substrate 11, and then this side is turned up and fired at a temperature around the softening temperature, and then cooled (rehardened). Then, an insulating layer 31 is formed. Since the firing temperature of the insulating layer 31 is set lower than the softening temperature of the insulating layer 30, the previously formed insulating layer 30 does not melt and adhere to the setter or the inner wall of the furnace.

Next, the N1 plating layer 15 and the Sn plating layer 16 are formed only on the outer surface of the end electrode 14 by immersing the ceramic substrate 11 in a plating solution. In this case, since the plating liquid does not adhere to the insulating layer 30.31, the plating layer 15.1 is applied only to the outer surface of the end electrode 14 by simply immersing the ceramic substrate 11 in the plating liquid.
6 can be formed.

In the above manufacturing process, the cutting process, the insulating layer forming process, and the end face electrode forming process, which are located between the forming process of the counter electrode 12 and the final plating process, can be carried out by changing the order of each as appropriate.

FIG. 2 shows a cross section of the capacitor thus produced (cross section taken along line Y--Y in FIG. 4). In the figure, the substrate end surface 13a
, 13b, no insulating layer is formed, and an insulating layer is formed in this portion (this requires separately applying and baking an insulating layer material by screen printing or the like).

Next, an example in which an insulating layer is formed on the substrate end faces 13a and 13b will be described. In this example, one or both of two types of insulating layer materials having different softening temperatures are compressed into powders to form a molded body, and this molded body is formed to be wider than the ceramic substrate 11. Ok,
The molded body and the ceramic substrate 11 are stacked, fired and cooled to form an insulating layer on the substrate end faces 13a and 13b.

A specific manufacturing method will be explained based on FIG.

A feature of the capacitor shown in FIG. 3 is that an insulating layer 32 is formed not only on the upper surface A of the II device substrate 11 but also on the substrate end surfaces 13a and 13b.

To manufacture this capacitor, as in the previous embodiment, a counter electrode 12 is formed on a ceramic material and then cutting is performed, and an end electrode 14 is formed on the resulting ceramic substrate 11. A molded body 33 made of an insulating layer material with a high softening temperature is superimposed on this ceramic substrate 11, and the insulating layer 33 is fired and cooled.
form 0. On the other hand, an insulating layer material having a low softening temperature is molded to be wider than the ceramic substrate 11, and this molded body 34 is placed on the ceramic substrate 11 and fired. Porcelain substrate 11 of molded body 34
The portion protruding from the insulating layer 32 is melted by firing and becomes the insulating layer 32.
This becomes part a and covers the substrate end faces 13a and 13b. By cooling (re-hardening), an insulating layer 32 is formed from the top surface of the ceramic substrate 11 to the substrate end surface], 3a, and 13b. Note that the insulating layer 32a portion may be formed by the molded body 33, or may be formed by both the molded bodies 33 and 34. Thereafter, by immersing the ceramic substrate 11 in a plating solution, the end electrode 1
4. A Ni plating layer 15 and a Sn plating layer 16 are formed only on the outer surface (FIG. 1).

In addition, in this embodiment, except that the step of forming the insulating layer 30.32 must be carried out after the cutting step, the step of forming the end face electrode 14 is carried out before the cutting step or after the step of forming the insulating layer 30.32. It's okay.

Table 1 shows the composition, softening temperature, and firing temperature of the glass used as the material for the insulating layers 30, 31, and 32 used in the above examples.

(Left below) The capacitor as an electronic component manufactured as described above has insulating layers 30 and 31 formed on both sides of the ceramic substrate 11.
．． The softening temperatures of the insulating layer materials in 32 are different, and the insulating layer material 30 with a high softening temperature is first coated with the insulating layer material, fired at a temperature near its softening temperature, and cooled, and then the insulating layer 31 with a low softening temperature is coated. 32, the insulating layer material is similarly applied, baked at a temperature close to its softening temperature, and cooled, so that the insulating layer 31 has a low softening temperature.
．． In the process of forming the insulating layer 32, the previously formed insulating layer 30 having a high softening temperature does not melt. Therefore, the shape of the insulating layer 30 is not deformed or the thickness thereof is not uniform, so that the yield of products can be improved.

In addition, since the insulating layer 30 that has already been formed and has a high softening temperature does not melt, the insulating layer material can be re-hardened without changing the shape of the insulating layer 30.
It becomes possible to increase the thickness of the insulating layer. Therefore, defective parts such as pinholes and extremely thin parts that cause the plating liquid to penetrate into the ceramic substrate 11 are hardly generated, so that the reliability of the electronic component can be improved.

Furthermore, when forming the insulating layer 32a on the substrate end faces 13a, 13b, the molded body 34 of the insulating layer material is formed wider than the ceramic substrate 11, and the molded body 34 and the ceramic substrate 11 are overlapped and fired. When the part of the molded body 34 protruding from the ceramic substrate 11 is melted by firing, the end surface 1 of the substrate is melted.
3a and 13b can be crested, and an insulating layer 32a can be formed in these parts. Therefore, without increasing the number of steps, the substrate end face 13. Since the insulating layer 32a can be easily formed on the substrate edges 13a and 13b, it is possible to prevent the plating liquid from penetrating into the ceramic substrate 11 from the substrate end surfaces 13a and 13b.6 Note that the present invention is not limited to capacitors. Needless to say, the present invention is applied to all electronic components that form an insulating layer.

As is clear from the above explanation, in the electronic component and the manufacturing method thereof according to the present invention, the softening temperatures of the materials of the insulating layers formed on both sides of the substrate are different, and the insulating layer has a high softening temperature. The layer is first coated with an insulating layer material, baked at a temperature near its softening temperature, and cooled. Next, the insulating layer material with a low softening temperature is similarly coated, baked at a temperature near its softening temperature, and cooled. Therefore, in the process of forming an insulating layer with a low softening temperature, the already formed insulating layer with a high softening temperature does not melt. Therefore, the insulating layer will not be deformed or the thickness will not be non-uniform, so the yield of products can be improved.

In addition, since the insulating layer that has already been formed with a high softening temperature will not melt, the insulating layer material can be re-hardened without changing the shape of the insulating layer, making it possible to increase the thickness of the insulating layer. becomes possible. Therefore, defects such as pinholes and extremely thin parts that cause the plating liquid to penetrate into the ceramic substrate are reduced, thereby improving the reliability of the electronic component.

Furthermore, when forming an insulating layer on the end surface of the substrate, one or both of the insulating layer materials is molded to be wider than the substrate, and the molded body and the substrate are overlapped and fired, so that the molded body protrudes from the substrate due to overlapping. When the portion is melted by firing, it can cover the end surface of the substrate to form an insulating layer on the end surface of the substrate. Therefore, an insulating layer can be easily formed on the end face of the substrate without increasing the number of steps, and it is easily possible to prevent the plating liquid from penetrating into the ceramic substrate from the end face of the substrate.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of a capacitor as an electronic component according to the present invention, and FIG. 2 is a sectional view taken along the line X-X in FIG. 4, and FIG. 3 is a cross-sectional view taken along line Y-Y in FIG. 4 showing another example of a method for manufacturing an electronic component, FIG. 4 is a plan view showing electronic components according to the conventional and the present invention, and FIG. x-x' at
ys sectional view, FIG. 6 is a Y-Y 19 sectional view in FIG. , 30... Insulating layer with high softening temperature, 31. 32... Insulating layer with low softening temperature, 33... Molded body with high softening temperature,
34...Molded body with low softening temperature, A...Substrate surface,
B...Other side of the board

Claims (3)

[Claims] (1) A counter electrode formed on a portion including one surface of the substrate and a portion including the other surface, an end electrode connected to the counter electrode, and an insulation between these counter electrodes formed on both surfaces of the substrate. In an electronic component equipped with an insulating layer for
An electronic component characterized in that the materials of the insulating layers formed on both sides of the substrate have different softening temperatures. (2) Opposing electrodes are formed on a portion including one side of the substrate and a portion including the other side, and then an insulating layer material with a high softening temperature is applied to one side of the substrate and baked at a temperature near the softening temperature. manufacturing an electronic component, comprising the steps of applying an insulating layer material with a low softening temperature to the other surface of the substrate, firing it at a temperature near the softening temperature, and cooling the substrate. Method. (3) forming an insulating layer on the end surface of the substrate by forming one or both of the insulating layer materials according to claim 2 to be wider than the substrate, overlapping the formed body and the substrate, and firing and cooling the formed body; Methods for manufacturing electronic components including;