JPH08148302A - Chip part - Google Patents

Abstract

PURPOSE: To provide a chip part of recessed electrode construction designed to enhance automatic soldering test precision through image recognition. CONSTITUTION: A device is placed on a cream solder of a circuit substrate by forming an insulating film 8 covering part of a recessed-shape electrode 5 formed on a plurality of recesses set up at a preset pitch on an insulating substrate 1. At the time of reflow, the solder is sucked only up to the insulating film 8. Since the projection length of a solder fillet projected onto the circuit board becomes long, when an automatic soldering test is conducted by image recognition, an erroneous judgment that no soldering has been made because of a short projection length is prevented and a high test inspection precision is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a chip component having a concave electrode provided in a concave portion at the edge of a substrate used in an electronic circuit.

[0002]

2. Description of the Related Art In recent years, there has been a demand for improving the accuracy of automatic soldering inspection performed by image recognition after mounting a chip component having a concave electrode structure on cream solder on a circuit board.

A conventional chip component will be described below. Chip components such as multiple chip devices have been developed as composite components of square chip devices, which are surface-mounted components, and are made of substantially the same material as the square chip devices. The electrode structure of such a multiple chip element is divided into two types, that is, a convex electrode and a concave electrode, as shown in FIGS. 3 and 4, depending on the supplier.

Among them, a multiple chip element having a convex electrode structure as shown in FIG. 3 is an insulating substrate 1 having a plurality of concave portions 2 formed at a predetermined pitch by dividing a through hole portion of the substrate, It is composed of a convex electrode 3 provided on the insulating convex portion, a plurality of elements (not shown) formed between the convex electrodes 3, and a protective film 4 covering the element.

Next, as shown in FIG. 4, in the multiple chip element having the concave electrode structure, the insulating substrate 1 having a plurality of concave portions 2 having a predetermined pitch is also formed by dividing the through hole portion of the substrate. And the concave electrode 5 having the concave electrode structure provided in the concave portion 2.
Although not shown, it is composed of a plurality of elements formed between the concave electrodes 5 and a protective film 4 covering the elements.

[0006] Chip components having a convex electrode structure as described above generally have a problem in that a solder bridge is likely to occur during reflow soldering, making it difficult to obtain a self-alignment effect. Accepted by the market.

[0007]

However, in the above-mentioned conventional configuration, the chip component having the concave electrode structure is mounted on the same land pattern and cream solder as the chip component having the convex electrode structure, and after reflowing, the image recognition is performed. When an automatic soldering inspection (binarized display by light reflection) is performed, the surface area of the concave electrode 5 is larger than that of the convex electrode 3,
Despite being soldered, the amount of solder sucked up is large, and as shown in FIG. 5, the projected length 6a of the solder fillet 6 projected onto the substrate to be mounted is shortened and the soldering is not performed. It had a problem that it was determined that it was not.

The present invention solves the above-mentioned problems of the prior art, and has a recessed electrode structure capable of passing the automatic soldering inspection after soldering while maintaining the conventional self-alignment effect while the solder fillet 6 is sufficiently long. The purpose is to provide chip parts.

[0009]

In order to achieve this object, a chip component of the present invention comprises an insulating substrate having a notched concave portion at a side end, a concave electrode provided in the concave portion, and the concave electrode. And an insulating film that covers a part of the concave electrode.

[0010]

According to this structure, since the insulating film is formed on a part of the concave electrode, when the chip component is mounted on the cream solder of the circuit board and reflowed, the solder is absorbed only up to the insulating film. The length of the solder fillet projected onto the board to be mounted does not rise, and the length (projection length) becomes long. Therefore, when the automatic soldering inspection by image recognition is performed, the length is short, so it is not soldered. Can be prevented.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A multiple chip resistor will be described below as an example of a chip component having a concave electrode structure according to an embodiment of the present invention with reference to the drawings.

FIG. 1 is a perspective view showing a multiple chip resistor having a concave electrode structure according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a state in which the chip resistor is mounted.

The multiple chip resistor in this embodiment is, for example, an insulating substrate 1 made of ceramic or the like having a plurality of recesses 2 having steps 2a formed by dividing a through hole portion of the insulating substrate 1 at a predetermined pitch. A plurality of concave electrodes 5 formed in the concave portion 2 and connected to the concave electrodes 5,
It is composed of a plurality of resistance films 7 formed on the surface of the insulating substrate 1.

As shown in FIG. 1, the concave electrode 5 is made of Ag,
It is formed by printing an electrode paste such as Ag-Pd or Cu and firing it. In addition, each concave electrode 5
Are continuously formed up to the edges of the front and back surfaces of the insulating substrate 1. The resistance film is formed by printing and baking a cermet resistance paste such as ruthenium oxide straddling between the front end portions of the pair of concave electrodes 5 facing each other.

Further, the protective film 4 is formed so as to cover the resistance film 7.
Then, the insulating film 8 is formed on the concave electrode 5 so as to cover about one third of the surface area of the concave portion 2. In this case, the recess 2 is provided with a step 2a, which prevents the insulating film 8 from being formed downward. The protective film 4 and the insulating film can be formed by printing with an insulating paste such as glass or resin and firing or curing.

In the multiple chip resistor having the concave electrode structure constructed as described above, since the insulating film 8 is formed on the upper third of the concave electrode 5, the circuit board as shown in FIG. When a multiple chip resistor is mounted on the cream solder and reflowed, the solder is sucked up only to the formation start position of the insulating film 8, and the projected length 6a of the solder fillet 6 projected onto the circuit board becomes long. . As described above, according to the present embodiment, when the automatic soldering inspection by image recognition is performed by forming the insulating film 8 covering the upper third of the concave electrode 5, the projection length 6a is short, It is possible to prevent the problem of the conventional chip component having the concave electrode structure that is determined not to be attached.

When a multiple chip resistor having a concave electrode structure having the above structure was actually manufactured, mounted on cream solder of a circuit board, and reflowed, the projected length of the solder fillet was about 1 .5 times longer,
When an automatic soldering inspection was performed by recognizing 5000 pieces, 0% were judged not to be soldered.

In this embodiment, a multiple chip resistor having a plurality of resistance films formed as elements has been exemplified.
Regardless of the number and types of such elements and the number of concave electrodes, the same effect can be obtained as long as the chip component has the concave electrodes. Further, when the area of the insulating film formed in the concave portion of the substrate is 1/3 or more of the surface area of the concave portion, the same effect was obtained.

[0019]

As described above, according to the present invention, since the insulating film is formed on the upper portion of the concave portion of the substrate where the concave electrode is formed, the chip component is mounted on the cream solder of the circuit board and reflowed. After that, the solder sucks up only to the position where the insulating film is formed, and the projected length of the solder fillet projected on the circuit board becomes long, so when the automatic soldering inspection by image recognition is performed, it is not soldered. It is possible to prevent the problem that it is determined that the high inspection accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view of a chip component having a concave electrode structure according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the chip component in a mounted state.

FIG. 3 is a perspective view of a conventional chip component having a convex electrode structure.

FIG. 4 is a perspective view of a conventional chip component having a concave electrode structure.

FIG. 5 is a side view of a solder fillet when a chip component having a conventional concave electrode structure is mounted.

[Explanation of symbols]

 1 Insulating Substrate 2 Recess 2a Step 4 Protective Film 5 Recessed Electrode 7 Resistive Film 8 Insulating Film

Claims (2)

[Claims] 1. An insulating substrate having a notched recess at a side end, a recessed electrode provided in the recess, an element electrically connected to the recessed electrode, and a part of the recessed electrode. A chip part having an insulating film. 2. The chip component according to claim 1, wherein a step is provided in the recess.