JP2001332407A - Chip type electronic parts and method of manufacturing chip resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide chip type electronic parts on which the surface of a protective film is flattened and electrode patterns in both end sections are formed clearly and, accordingly, can be recognized automatically and accurately even when the parts are formed in a very small size and a method for manufacturing a chip resistor as an concrete example of the parts. SOLUTION: In the chip type electronic parts, a pair of first upper-surface electrodes 21a and 31a is provided in both end sections facing each other on the surface of an insulating substrate 1 made of alumina, etc., and a resistor 4 is provided on the substrate 1 so that both end sections of the resistor 4 may be connected electrically to the electrodes 21a and 31a. In addition, a pair of thick-film second upper surface electrodes 21b and 31b is provided on the first upper surface electrodes 21a and 31a, respectively, and a protective film 5 is formed on the surface of the resistor 4 between the electrodes 21b and 31b to cover the side walls of the electrodes 21b and 31b by curing low- viscosity paste so that the surface of the film 5 may become flat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip-type insulating substrate, such as a chip resistor, a chip inductor or a chip fuse, provided with a pair of electrodes at both ends of a chip-type insulating substrate, and an electronic device connected therebetween. The present invention relates to a method for manufacturing an electronic component and a chip resistor having a structure in which a chip is covered with a protective film. More specifically, even when the length is extremely small, for example, about 1 mm or less, the chip type electronic component and the chip have a structure in which the surface of the protective film is flat and the shape of the electrodes at both ends can be accurately recognized. The present invention relates to a method for manufacturing a resistor.

[0002]

2. Description of the Related Art A conventional chip resistor is, for example, shown in FIG.
The structure is as shown in FIG. That is,
In FIG. 4A, a pair of thick film electrodes 2 and 3 are provided on a first upper electrode 2 at opposite ends of an insulating substrate 1 made of alumina or the like.
1a, 31a, the second upper surface electrodes 21b, 31b, the back surface electrodes 22, 32, and the side electrodes 23, 33 connecting these.
The thick film resistor 4 is formed on the insulating substrate 1 so as to be connected to both electrodes. A thick protective film 5 is formed in one to three layers on the surface side of the resistor 4. The thick film is formed to a thickness of about 5 to 10 μm.

[0003] Chip electronic components such as chip resistors having the above-described structure are originally formed in a small size. However, as electronic devices become lighter and thinner, for example, in a plan view shown in FIG. , Length A x width B is 1mm x 0.5mm
Therefore, a size of about 0.6 mm × 0.3 mm is required. Even when such a small-sized device is mounted on a circuit board or the like, it is mounted by an automatic machine, and the position of the electronic component is confirmed by recognizing the position of the electrode on the surface. However, the width C of the upper electrodes 21b and 31b is only about 0.1 mm, and
The boundaries between the protective films 1b and 31b and the protective film 5 are notched as shown in the plan view of FIG.
b and 31b cannot be accurately recognized.

That is, in order to protect the surface of the resistor 4 whose resistance value has been adjusted by laser trimming or the like, a protective film 5 is first formed on the surface, and the thickness of the protective film 5 is about 20 to 30 μm. In addition, since the second upper surface electrode material must be printed in a narrow concave portion having irregularities, the mask does not adhere to each other, and it is difficult to form a fine pattern of the second upper surface electrodes 21b and 31b. Further, if the viscosity of the paste for forming the protective film 5 is low, the paste flows on the first surface electrodes 21a and 21b, so that the paste having a viscosity of at least 100 Pa · s or more, usually about 200 Pa · s is used. Is less than about 0.5 mm, the upper surface is not flat, and a convex surface is easily formed by surface tension. For this reason, the second upper surface electrodes 21b and 31b are formed so as to overlap with the protective film 5, and the boundary surface is jagged, making it difficult to recognize the electrode pattern.

On the other hand, as shown in FIG. 5, a middle coat 51 is provided on the resistor 4 so as to first fill the groove cut at the time of adjusting the resistance value.
The method of forming b and 31b may be adopted. In this case, the middle coat 51 and the second upper electrode 21b, 3
1b is substantially flat, and the second
The protective film 52 can be formed in a clear pattern. However, if the second protective film 52 is not provided with a thickness of about 20 to 30 μm, a pinhole is likely to occur, and the groove cannot be completely filled by laser trimming to planarize the surface. The step t between the first and second protective films 21b and 31b and the surface of the second protective film 52 is about 20 to 30 μm, and similarly, it is difficult to automatically recognize the electrode surface.

[0006]

As described above, a conventional chip-type electronic component such as an inexpensive chip resistor is manufactured by forming a material such as an electrode material or a resistor into a paste and printing and curing the material. However, as the size of the component becomes smaller, it becomes more difficult to precisely perform the printing pattern. However, in a mounting method in which the position is confirmed by recognizing an electrode pattern, for example, a chip-type electronic component having a structure capable of accurately recognizing the electrode pattern and the like even if the size is reduced is desired.

Further, as described above, as the thickness of the protective film increases, the surface of the protective film cannot be made flat, and there is a problem that it is difficult to perform vacuum suction or the like when mounting.

The present invention has been made in view of such circumstances, and even in a very small chip electronic component, the surface of the protective film is flattened, and the electrode patterns at both ends are clearly formed, so that accurate It is an object of the present invention to provide a chip-type electronic component having a structure that can be automatically recognized.

Another object of the present invention is to provide a specific method for manufacturing a chip resistor for forming such electrode patterns at both ends clearly.

[0010]

A chip-type electronic component according to the present invention comprises an insulating substrate, a pair of first upper electrodes provided at opposite ends of the substrate, and a pair of the first upper electrodes. An electronic element provided on the substrate such that both ends are electrically connected, a pair of thick second upper electrodes provided on the pair of first upper electrodes, and a paste having a low viscosity is cured. By doing so, the pair of second
A protective film provided on the surface of the electronic element so as to cover the side wall of the upper electrode and to make the surface flat.

Here, the term "thick film" means a film which is formed thick by applying and curing an electrode material in the form of a paste. Further, the electronic element means an element constituting a main part of an electronic component, such as a resistor and an inductor element.

According to this structure, a pair of second upper electrodes having a narrow pattern are formed first, and a paste having a low viscosity is poured into a concave portion sandwiched between the second upper electrodes and is cured to form a protective film. Are formed, the surface of the protective film is flattened, and the second upper surface electrode is formed in a substantially flat state before the protective film is formed. .1mm
It is formed so that even a very thin pattern can be accurately recognized. Since the second upper surface electrode is formed of a thick film formed by applying and curing a paste-like electrode material by printing or the like, as shown in FIG. It is formed in a shape. Therefore, the paste for the low-viscosity protective film printed between the two electrodes is provided so as to cover the side wall of the second upper electrode and is cured.

[0013] By further providing a pair of third upper electrodes on the second upper electrode, the third upper electrode is
Since it is sufficient that the electrode pattern is formed on a substantially flat surface with a thickness of about several μm, the electrode pattern can be further formed by a fine pattern.

The method of manufacturing the chip resistor according to the present invention is as follows.
(A) a pair of first upper electrodes are provided at both ends of the insulating substrate; and (b) a resistor is formed on the insulating substrate so as to overlap a part of the pair of first upper electrodes and form a predetermined shape. (C) forming a pair of second upper electrodes on each of the exposed surfaces of the pair of first upper electrodes, and (d) a surface of the resistor sandwiched between the pair of second upper electrodes. A protective film having a flat surface is formed by applying a low-viscosity paste and curing the paste.

The paste having a small viscosity is 50 Pa
By using a paste having a viscosity of not more than s, the paste flows between the pair of second upper electrodes, and a protective film having a flat surface can be formed.

[0016]

Next, a chip resistor according to the present invention will be described with reference to the drawings. A chip resistor according to the present invention is, as shown in FIG. 1 in a cross-sectional explanatory view of one embodiment thereof, provided at opposite ends of an insulating substrate 1 made of, for example, alumina and having a rectangular planar shape. A pair of first upper electrodes 21a, 31a are provided, and the electronic element, in the example shown in FIG. 1, a resistor is provided so that the pair of first upper electrodes 21a, 31a are electrically connected to both ends. A body 4 is provided on the substrate 1. A pair of thick second upper electrodes 21b and 31b are provided on the pair of first upper electrodes 21a and 31a, respectively. The surface of the resistor 4 is provided between the pair of second upper electrodes 21b and 31b. The protective film 5 is provided by hardening a paste having a low viscosity so as to cover the side walls of the second upper electrodes 21b and 31b and to make the surface flat.

That is, in order to manufacture this kind of electronic component, a material constituting an electronic element such as an electrode material and a resistor is formed by pasting glass or resin into a paste and is applied by printing or the like. By baking (in the case of a glass paste) or curing at a temperature of about 200 to 240 ° C. (in the case of a resin paste), and by forming a film by a sputtering method and patterning by a photolithography process. Although there is a thin film method for forming, the present invention mainly uses a thick film method which can be manufactured at a low cost, and at least the second upper surface electrodes 21b, 31b and the protective film 5 are formed of a thick film while a very small-sized method is used. Chip-type electronic components are also characterized in that their top electrodes are formed in a fine pattern.

As the substrate 1, for example, alumina, sapphire, or Si wafer is used. As a thick-film electrode material, generally, a material obtained by mixing a metal powder and glass or a resin to form a paste is used, and depending on the metal powder to be mixed, an Ag-based, Ag-Pd-based, Au-based, or the like is used. However, in the example shown in FIG. 1, a thick film electrode made of an Au-based glass paste is used as the first upper electrodes 21a and 31a, and an Ag-based resin paste is used as the second upper electrodes 21b and 31b. ing. Here, the term “system” includes a substance mainly containing Ag and to which other elements such as Pd are added.

In the example shown in FIG. 1, the second upper electrode 21
a protective film 5 is formed between the first upper electrode 2
After the heights of 1b, 31b and the protective film 5 are substantially equal, the third upper electrodes 21c, 31c made of Ag-based resin paste are formed on the second upper electrodes 21b, 31b. Further, on the back surface of the substrate 1, Au-based glass paste or Ag-based resin paste is applied to both ends corresponding to the upper surface electrode and cured to form rear surface electrodes 22, 32, and the upper surface electrodes 21, 32 are formed. Side electrodes 23 and 33 are formed on the side surfaces of the insulating substrate 1 by thick film electrodes made of an Ag-based resin paste so as to connect the base 31 and the back electrodes 22 and 32. A pair of electrodes 2 and 3 is formed by providing a plating layer made of Ni plating and solder plating (not shown) on the surface of this electrode.

The resistor 4 is made of, for example, ruthenium oxide (R
It is formed by applying a paste material obtained by mixing uO ₂ ) and Ag, Pd or the like for adjusting a resistance value into a glass paste or a resin paste into a desired shape by printing or the like and curing the paste. Note that the resistor 4 is not a thick film, but a Ni—Cr-based, Ta-based, Ta—N-based, TaSiO
_It may be formed as a thin film by selecting a Ta-Si based metal film such as ₂ according to a desired resistance value, forming a film by sputtering or the like, and patterning it into a desired shape.

The protective film 5 is formed by applying and curing a resin paste such as an epoxy resin by printing or the like. Normally, pastes applied by this type of printing have a viscosity of about 200 Pa · s, and at least about 100 Pa · s or more, because the paste drips sideways when the viscosity is small and it is difficult to form a desired shape. You.
However, in the present invention, this viscosity is reduced to 50 Pa
-It is characterized by using a paste that is easy to flow, s or less.

That is, in the present invention, the second upper electrode 21
Since b and 31b are formed and are filled in such a way that they are poured, they do not hang sideways. That is, as shown in FIG. 2, in the manufacturing stage, tens of thousands of resistors are manufactured at a time on a large substrate, and finally divided into bars in line L1, and further divided into individual chips in line L2. Divided. Therefore, a pair of electrodes are arranged in a plurality of rows in the horizontal direction, and as shown by arrows in FIG. 2, a resin paste having a low viscosity is applied between the pair of electrodes 21 and 31 so as to be filled with a squeegee or the like. ing. As a result, even if the printing mask is not properly aligned, the resin paste is applied between the pair of electrode rows and the surface is flattened due to low viscosity, so that the flat protective film 5 is obtained. Can be The pair of second upper electrodes 21
Similarly, b and 31b are formed by application of a paste, and the base is slightly peeled off. Therefore, the protective film 5 is formed so as to overlap on the part where the base is broken.

In the example shown in FIG. 1, the protective film 5 is shown as a single layer, but a first protective film is first formed on the surface of the resistor 4 and the resistor 5 is removed by laser trimming. A three-layer structure in which a powder or the like is not attached to affect the resistance characteristics, and a second protective film is provided to fill the trench dug by laser trimming, and a final third protective film is formed thereon. Or a two-layer structure including a first protective film and a third protective film. Also in these cases, the final protective film is formed by applying and curing a paste having a low viscosity after the second upper surface electrode is formed.

Since the final protective film 5 may change its resistance value when fired at a high temperature, a resin paste made of an epoxy resin or the like is applied as in the above-described example. Then, it is preferable to cure at about 200 to 240 ° C. However, printing a glass paste using lead borosilicate glass or the like,
Sintering can be performed to a degree.

Next, a method of manufacturing the chip resistor will be described with reference to a flowchart shown in FIG. FIG. 1 shows a cross-sectional explanatory view of one chip resistor. However, when actually manufacturing the chip resistor, as shown in FIG. 2 described above, one chip resistor is mounted on a large substrate of about 6 cm × 7 cm. About 50,000 to 50,000 electrodes and resistors are formed at the same time,
It is manufactured by forming side electrodes on the exposed side surfaces by cutting it into a bar shape, and then cutting and separating the chip resistors connected in a bar shape one by one.

First, an Ag-based glaze paste or a paste of an electrode material made of an Au-based metal organic material is printed on a predetermined location on the back surface of the substrate 1. Then, baking is performed at about 600 to 900 ° C. to form thick back electrodes 22 and 32 (see FIG. 1) (S1). Next, an electrode material made of, for example, an Au-based or Ag-based metal organic material (glass paste) is applied to portions corresponding to the back electrodes 22 and 32 (both ends of the chip resistor) on the surface of the substrate 1 by printing and sintering. Thereby, the first upper surface electrodes 21a and 31a are formed (S2). Then, ruthenium oxide (RuO ₂ )
Is printed in a predetermined shape on the substrate 1 between the first surface electrodes 21a and 31a at both ends so as to cover a part of the upper surface electrodes 21a and 31a, and is baked. Thus, the resistor 4 is formed (S3).

Thereafter, the pair of first upper electrodes 21a, 31
While contacting the probe electrode to a and measuring the resistance value,
Laser trimming is performed to adjust the resistance value to a desired resistance value (S4). Then, for example, Ag and Pd
-Based organic paste (resin paste) mixed with resin
Is formed on the first upper electrodes 21a and 31a by printing and cured at about 200 ° C. to form the second upper electrodes 21b and 31b (S
5).

Next, a mask is placed on the surface and the viscosity becomes 5
A resin paste made of an epoxy resin of 0 Pa · s or less is applied to the gap between the second upper electrodes 21b and 31b by printing. At this time, as shown in FIG.
By applying a paste on a mask provided on the surface with a squeegee along the gap between 1b and 31b,
A paste having a low viscosity is applied so as to flow between the second upper electrodes 21b and 31b. And 200 to 24
By curing at about 0 ° C., the protective film 5 having a flat surface is formed (S6). Then, the second upper surface electrode 21
b, 31b and a third upper electrode 21 made of a similar material.
c and 31c are formed to a thickness of about 5 μm (S7). Since the patterns of the second upper electrodes 21b and 31b are accurately formed, the third upper electrodes 21c and 31c may not be provided. However, since the third upper electrodes 21c and 31c can be formed on a substantially flat surface, A finer pattern can be obtained.

Next, a large substrate is placed on a pair of upper electrodes 2.
2 is cut in a bar shape along the line L1 in FIG. 2 so as to be separated for each line arranged in a direction perpendicular to the direction connecting the lines 1 and 31 (S8). Then, the upper surface electrodes 21 and 31 and the back surface electrode 2
By applying and curing an electrode material made of an Ag-based resin paste so as to connect the electrodes 2 and 32, the side electrodes 23 and 33 are formed (S9). Thereafter, the chip resistors connected in a bar shape are divided into chips in a line L2 in FIG. 2 (S10), and the exposed surfaces of the electrodes are plated with Ni and Pb / Sn by solder plating. The chip resistor shown in FIG. 1 is obtained (the plating layer is not shown).

According to the present invention, even when the size of the electrode is extremely small and a fine pattern electrode cannot be formed with high accuracy on a portion having a large step, the second upper surface electrode is formed at an early stage when the step is not large, and thereafter the viscosity of the second upper electrode is reduced. Since the protective film is formed by applying and curing a small paste, the surface of the protective film is flat and formed only between the second upper electrodes. Furthermore, the second
By forming the third upper surface electrode on the upper surface electrode, the third upper surface electrode is formed on a substantially flat surface. Therefore, the third upper surface electrode is formed with a finer pattern, and a very small chip resistor is used. Formed exactly.

The above-described example is an example of a chip resistor. However, like a chip inductor or a chip fuse, a chip-type substrate has a pair of electrodes at both ends and is connected to the pair of electrodes. In the case where an electronic element such as a resistor is formed on the surface and a protective film is formed on the surface, the upper surface electrode is formed first, and a low-viscosity paste is applied and cured during that time to flatten the surface. Protective film can be formed.

[0032]

According to the present invention, the electrodes on the surface of even a very small chip type electronic component are formed in an accurate pattern. Accurate alignment can be performed.
Furthermore, even when vacuum suction is performed at the time of mounting, since the surface of the protective film is formed flat, suction can be performed at that part. can do. As a result, it greatly contributes to further miniaturization of the chip electronic component.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing one embodiment of a chip resistor according to the present invention.

FIG. 2 is an explanatory plan view of a large substrate in a manufacturing process of the chip resistor of FIG. 1;

FIG. 3 is a flowchart of an example of manufacturing the chip resistor of FIG. 1;

FIG. 4 is an explanatory sectional view showing a structural example of a conventional chip resistor.

FIG. 5 is an explanatory sectional view showing another example of the structure of the conventional chip resistor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2, 3 electrode 4 Resistor 5 Protective film 21a, 31a 1st upper surface electrode 21b, 31b 2nd upper surface electrode 21c, 31c 3rd upper surface electrode

Claims (4)

[Claims] 1. An insulating substrate, a pair of first upper electrodes provided at opposite ends of the substrate, and the substrate so that both ends of the pair of first upper electrodes are electrically connected to each other. An electronic element provided thereon, a pair of thick-film second upper electrodes provided on the pair of first upper electrodes, and a side wall of the pair of second upper electrodes by curing a paste having a low viscosity. So that the surface becomes flat
A chip-type electronic component comprising a protective film provided on a surface of the electronic element. A second pair of third electrodes on the second upper surface electrode;
The chip-type electronic component according to claim 1, further comprising an upper electrode. 3. A pair of first upper electrodes are provided at both ends of an insulating substrate, and the insulating layer is formed so as to overlap a part of the pair of first upper electrodes and have a predetermined shape. (C) forming a pair of second upper surface electrodes on each of the exposed surfaces of the pair of first upper surface electrodes,
(d) A method for manufacturing a chip resistor, wherein a low-viscosity paste is applied to the surface of the resistor sandwiched between the pair of second upper electrodes and cured to form a protective film having a flat surface. . 4. The paste having a small viscosity is 50P.
4. The method for manufacturing a chip resistor according to claim 3, wherein a paste having a viscosity of not more than a · s is used.