JP2000068103A - Chip electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip electronic part capable of miniaturizing a printed wiring board on which the electronic parts are mounted. SOLUTION: Electrodes 3 are provided on both opposite ends of a surface 1a in an insulating substrate 1, respectively, and resistive elements 2 as electric part are provided on the surface 1a of the insulating substrate 1 and electrically connected to both electrodes 3. Through-holes 6 are provided on both ends of the insulating substrate 1, respectively, so that the hole sectional area on the rear surface 1c of the substrate 1 is greater than that on the surface 1a of the insulating substrate 1. In the through-holes 6, conductive films 7 are provided so as to be electrically connected to the electrodes 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a chip-type electronic component such as a resistor, a capacitor, an inductor, and a semi-fixed volume. More specifically, a chip type that does not require a space for a solder fillet on the side wall side of a small electronic component, allows adjacent electronic components to be arranged close to each other, and can reduce the size of a circuit board for assembling chip type electronic components. Related to electronic components.

[0002]

2. Description of the Related Art A conventional chip-type electronic component is shown in FIG.
As shown in a partially cutaway perspective view in FIG.
b, the electrode 23 and the conductor film 24 are provided, and the surface 21 a
Is provided with an electric element 22 such as a resistor so as to be connected to the electrodes 23 at both ends.
Is formed by covering the surface with a protective film 25. The chip-type electronic component 20 is small, for example, about 1 mm × 0.5 mm in length and width, and is directly mounted on a circuit board (not shown) with its back surface 1 c side down by soldering or the like. At this time, the chip-type electronic component 2 is electrically connected to the conductor film 24 on the side surface.
In order to maintain the mechanical strength of the bonding of No. 0, a land pattern is formed on the circuit board (not shown) so that the solder fillet 26 is sufficiently formed on the conductor film 24 on the side surface, as shown in FIG. Is formed to be larger than the outer shape.

[0003] As described above, the mounting structure of the chip-type electronic component is, for example, as shown in FIG. 4 (b), a multiple chip component on which a plurality of sets of unillustrated electric elements and electrodes 23 are mounted, or concave portions on the side surfaces. In the case of a component having a structure in which 27 is formed, a structure in which a solder fillet 26 is formed on the side surface of a chip-type electronic component and soldered to a circuit board or the like is employed.

[0004]

As described above, since the conventional chip-type electronic component 20 is attached to the circuit board by forming a solder fillet on its side wall, the area of the back surface 21c of the insulating substrate 21 is reduced. In addition, a land pattern for the solder fillet 26 is formed on the circuit board, and requires a larger area than the area of the chip-type electronic component. Further, since the solder fillet 26 is provided on the side surface of the chip-type electronic component, there is a danger that the chip-type electronic component will come into contact with the adjacent component unless a sufficient space is provided between the component and the adjacent component. Therefore, there is a problem that the miniaturization of the circuit board is prevented and the number of components that can be mounted on the circuit board is limited. On the other hand, when the bottom area of the solder fillet is reduced, there is also a problem that the fixing force of the chip-type electronic component to the circuit board is greatly reduced.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a chip-type electronic component capable of reducing the size of a circuit board on which the chip-type electronic component is mounted.

[0006]

According to the present invention, there is provided a chip-type electronic component, comprising: an insulating base; electrodes provided on opposite surfaces of the insulating base; and electrodes provided on the surface of the insulating base. And an electric element provided by being electrically connected between the electrodes at both ends, wherein through-holes penetrating from the front surface to the back surface are provided at both ends where the electrodes of the insulating base are provided, and A conductor film is provided in the through hole and electrically connected to the electrode.

[0007] Here, the through hole means that the front surface communicates with the back surface. For example, a concave portion is provided on the rear surface side of the insulating base, and a through hole is provided on the front surface side so as to communicate with the concave portion. It is meant to include what is being done.

According to this structure, the conductor film is formed under the electrode of the chip-type electronic component through the insulating substrate, and the exposed conductor film is not provided on the side surface. For example, when soldering is performed, the solder fillet is formed in the through hole and is not formed on the side wall of the chip-type electronic component, and can be soldered within the planar area of the component. As a result, components can be highly integrated on a circuit board or the like.

Since the through-hole has a small cross-sectional area on the front surface side of the insulating base and a large cross-sectional area on the back surface side of the insulating base, a sufficient area for providing electric elements on the front surface can be obtained. In addition, the solder fillet can be formed with a sufficient area when soldering to the circuit board or the like on the back surface side, and the reliability of the adhesive force can be improved.

[0010]

Next, a chip type electronic component according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, a chip-type electronic component according to an embodiment of the present invention has a partially cut-away perspective view of a chip-type resistor. An electrode 3 is provided, and a resistance element 2, which is an electric element, is provided on a surface 1 a of the insulating substrate 1 so as to be electrically connected to both electrodes 3. In the example shown in FIG. 1, through holes 6 are provided at both ends of the insulating substrate 1, and the through holes 6 have a larger cross-sectional area on the back surface 1 c side than on the front surface 1 a side of the insulating substrate 1. And a conductive film 7 is provided in the through hole 6 so as to be electrically connected to the electrode 3.

The insulating substrate 1 is made of a ceramic such as alumina, for example, and is obtained by cutting a plate-like insulator having a thickness of about 0.2 to 0.5 mm, as shown in FIG. It is formed in a rectangular parallelepiped shape. This insulating substrate 1 is made, for example, by mixing alumina powder with a binder and a solvent to form a liquid viscous material, for example, adjusting the thickness on a roll of a spreader, spreading it thinly, and drying it to form an unfired ceramic sheet, a so-called green sheet. Further, it is formed by firing this, or by pressing a powder such as an alumina powder directly into a plate-shaped body and sintering it.

As shown in FIG. 1, for example, the through hole 6 is formed as a stepped hole composed of a small hole 6a and a large hole 6b, or is formed in a tapered shape having a small diameter on the front surface 1a and a large diameter on the back surface 1c. Or formed in a normal through-hole shape. The size of the hole varies depending on the size of the chip component, but the small hole 6a is, for example, φ0.1 so as not to affect the electric element 2 provided on the surface 1a side of the insulating base 1.
The large hole 6b is formed, for example, at a diameter of about 0.2 to 0.4 mm so as to obtain mechanical strength with soldering without being affected by the electric element 2. The stepped through hole 6 is formed at the same time as the molding by forming the through hole portion of the molding metal with a step when, for example, the above-mentioned alumina powder is molded and sintered.
By sintering the molded body, the insulating substrate 1 having the stepped through holes 6 can be formed. In the case where the through hole 6 or the tapered through hole 6 having the same diameter is formed without such a step, the through hole 6 may be formed by punching with a mold in the state of the green sheet.

The conductor film 7 formed on the inner surface of the through hole 6
For example, the conductive paste is formed on one end of the through-hole 6 by applying the same conductive paste as an electrode material described later, and formed by through-hole printing sucking from the other end of the through-hole 6. Then, they are electrically connected to the electrodes 3 provided at both ends. After the resistive element 2 and the protective film 5, which will be described later, are formed, the surface of the conductor film 7 in the through hole 6 is plated with Ni and solder, so that the chip-type electronic component is soldered to a circuit board or the like. At the time of soldering, the solder is easily wetted, and the solder on the circuit board is easily soldered up to the surface side over the conductor film 7 in the through hole 6. That is, the solder is sufficiently filled in the large hole 6b and adhered over a large area, and the solder crawls into the small hole 6a and extends to the surface side of the insulating substrate 1 to be similar to the conventional solder fillet. It is provided to function.

The electrodes 3 are provided at both ends of the surface 1a of the insulating substrate 1. After sintering the insulating substrate 1, a conductive paste containing silver and palladium is applied by printing or the like and fired. Formed by The electrode 3 is also subjected to Ni plating and solder plating simultaneously with the plating of the conductor film 7. Although not provided in the example of FIG. 1,
A back surface electrode can be similarly formed on the back surface of the insulating substrate 1. By providing such a back surface electrode, the bonding area is increased when soldering to a circuit board or the like, and sufficient bonding strength can be obtained even with the through-hole having only the small through-hole 6 described above.

The resistance element 2 is formed by printing and firing a paste containing ruthenium oxide so as to straddle the electrodes 3 at both ends. The resistance element 2 varies depending on a desired resistance value. For example, the thickness is about 10 μm, and the size is 0.2 to 0.5 mm (length) × 0.1 to 0.3 mm.
(Width). When the resistance value does not reach the predetermined value due to manufacturing variations, a groove is formed on the surface of the resistance element 2 by laser trimming.
The resistance value is adjusted.

The protective film 5 protects the resistance element 2 and prevents the resistance value from changing or corroding due to impurities after completing the above-described resistance adjustment. It is formed by printing and firing a glass paste such as lead oxide glass, or by applying and solidifying a resin. At this time, the electrode 3 is provided so as to be exposed.

In order to manufacture such a chip-type electronic component, a plurality of chip-type electronic components of, for example, about 60 cm × 60 cm are formed in a state of an insulating substrate 1 having a size to form a matrix. By simultaneously performing the steps of manufacturing the chip-type electronic component. That is,
First, the insulating substrate 1 provided with the through-hole 6 as described above is formed, and the material for the electrode described above is screen-printed and through-hole printed in a portion to be an end of the chip-type electronic component and in the through-hole 6. The electrode 3 and the conductive film 7 are formed by applying and firing. Further, the resistance element 2 is formed so as to straddle both the electrodes 3, and the value is adjusted by a trimming process while measuring the resistance value of the resistance element 2. After that, a protective film 5 is formed on the resistance element 2. Then, the large insulative substrate 1 is cut into bars, and each bar is cut into chips to obtain chip-type electronic components. In the case where an electrode is also formed on the bottom surface of the chip-type electronic component, after printing the material for the electrode on the surface of the insulating substrate 1, the material for the electrode is further printed on a predetermined location on the back surface. Then, by sintering, a back electrode connected to the bottom surface via the conductive film 7 in the through hole 6 can be formed in the same manner.

Next, an example of soldering a chip type electronic component having this structure on a circuit board will be described with reference to FIG. First, as shown in FIG. 2A, a solder paste 13 is applied on a wiring pattern 12 of a circuit board 11 for connecting the electrodes 3 of the chip-type electronic component 10 together with other electronic components (not shown). The solder paste 13 is melted by placing the electronic component 10 on the circuit board 12 and placing it in a reflow furnace or the like, and as shown in FIG. The molten solder 13a crawls up. Then, a solder fillet is formed in the large hole 6b and the molten solder 13 is formed.
Since a crawls up to the upper surface, it can be confirmed by checking the upper surface that the solder 13a has sufficiently adhered into the through hole 6. Since the large hole 6b of the through hole 6 has a large cross-sectional area, a sufficient solder fillet is formed to exhibit a high fixing force to the circuit board 11.

According to the present invention, electrodes provided on both ends of a small chip-type electronic component are provided on the back side of the chip-type electronic component via a conductor film provided on a side wall of the chip-type electronic component. Instead of being connected to the circuit board, the conductor film is not provided on the side wall and connected to the circuit board provided on the bottom side of the insulating base via the conductive film in the through holes provided at both ends of the insulating base. Have been. for that reason,
The land pattern on the circuit board that connects the electrodes of the chip-type electronic component does not need to be formed large enough to protrude from the chip-type electronic component, and the conductor is not exposed on the side wall of the chip-type electronic component. And the mounting density of electronic components on the circuit board can be greatly improved. As a result, the circuit board can be downsized for the same circuit. Moreover, since the through hole of the chip-type electronic component has a large area such as a large hole on the bottom side, a sufficient solder fillet is formed in the large hole, and a sufficient bonding strength with the circuit board can be obtained. .

In the above-described example, the shape of the through hole is the example of the stepped hole 6. However, the through hole may be a tapered hole 16 as shown in FIG. . That is, although a large hole cannot be formed on the front surface side of the insulating substrate 1 due to the provision of the electronic component, it is preferable that the solder bonding area be as large as possible on the rear surface side in order to obtain sufficient bonding strength with solder. . Also,
As shown in FIG. 3B, the large hole portion 6b of the stepped through hole is not a hole, but a concave portion 1 that crosses the insulating substrate 1.
7 may be formed. As shown in FIGS. 3A and 3B, the through hole 6 including the tapered hole 16 and the through hole of the small hole 6a and the wide concave portion 17 also performs the same function. It can be punched out with a mold in the state of the unfired green sheet, and can be easily formed. Although not shown, if a back surface electrode is formed on the back surface of the insulating substrate, sufficient adhesive strength can be obtained, and the through hole may be a through hole that passes through as a thin hole. As described above, the through hole only needs to have a sufficient cross-sectional area for the solder bonding area with the circuit board, and the shape and the like are not limited.

In each of the above-described examples, a resistance element is used as an electric element. However, in addition to the resistance element, a capacitor, an inductor, a semi-fixed volume, or the like may be formed. Are provided at both ends, that is, one electrode is provided at one end.
Even in the case of multiple chip-type electronic components that are provided instead of individual components, through-holes are formed and solder is formed in the through-holes, so that electronic components can be similarly densely packed. Can be mounted.

[0023]

As described above, according to the present invention,
Because the conductor film is not provided on the side wall of the small chip-type electronic component, even when soldering to a circuit board,
No solder fillet is formed on the side surface of the electronic component. Therefore, components can be mounted in a mounting space with a clearance area corresponding to the component area and mounting accuracy, and the mounting density of electronic components can be improved. as a result,
A high-performance circuit can be formed with a small circuit board corresponding to recent miniaturization of electronic devices.

Further, since the through-hole is formed so that the cross-sectional area of the portion opened toward the back surface of the through-hole is increased, a high fixing force can be secured between the through-hole and the circuit board. Since the cross-sectional area on the surface side of the hole is small, an electric element such as a resistance element can be formed sufficiently large. Moreover, since the soldering state can be confirmed from the surface side of the through hole, the reliability of the soldering is greatly improved.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective explanatory view of one embodiment of a chip-type electronic component of the present invention.

FIG. 2 is an explanatory cross-sectional view showing a mounting state of the chip-type electronic component of FIG. 1 on a circuit board.

FIG. 3 is an explanatory sectional view of another embodiment of the chip-type electronic component of the present invention.

FIG. 4 is an explanatory view of a conventional chip-type electronic component.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating base 2 Resistance element 3 Electrode 5 Protective film 6 Through hole 7 Conductive film

Claims (2)

[Claims] 1. An insulating substrate, electrodes provided on the surfaces of opposite ends of the insulating substrate, and an electrode provided on the surface of the insulating substrate and electrically connected between the electrodes of the both ends. And a through hole penetrating from the front surface to the back surface at both ends where the electrode of the insulating substrate is provided, and is electrically connected to the electrode in the through hole. A chip-type electronic component provided with a conductive film. 2. The chip-type electronic component according to claim 1, wherein the through-hole has a small cross-sectional area on the front surface side of the insulating base and a large cross-sectional area on the back surface side of the insulating base.