JPH03241813A - Method of covering chip type electronic part - Google Patents

Abstract

PURPOSE:To prevent generation of a short-circuit by soldering even when a high density surface packaging operation is conducted by a method wherein, after liquid resin has been transfer-coated on both cut surfaces of an element formed by conducting a cutting work, the above-mentioned liquid resin is hardened. CONSTITUTION:After the process of formation of an electrode 2 on a base element has been finished, a process of formation of individual element 1 by cutting the base element 1 is conducted, and after both cut surfaces 4 of the element 2, formed by the above-mentioned process, are transfer coated with liquid resin 9 using a gravure roller 8, and then a process of hardening the above-mentioned liquid resin 9 is performed. For example, ultraviolet-ray-hardening resin 9a is carried on the gravure roller 8 by a lifting up roller and an intermediate transfer roller 6, and the excessive resin 9b, which does not go into the printing plate 3 of the gravure roller 8, is scraped off by a doctor blade 5, and the resin 9a is coated on the cut surface 4 only of the capacitor element 1. The coated ultraviolet-ray-hardening resin 9c is hardened by the irradiation of ultraviolet rays emitted from an ultraviolet ray lamp 10, and the resin 9c is thermoset further by a thermostatic vessel and the like as necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for packaging chip-type electronic components such as multilayer film capacitors.

Conventional chip-type electronic components have terminals soldered directly to printed circuit boards and are extremely small, making them suitable for highly integrated designs of electronic circuits. The exterior of chip-type electronic components includes a resin mold type, a button type covered with a resin coating, and a type without exterior.

Regarding the shape of the electrodes, for example, in chip-type multilayer ceramic capacitors, chip-type resistor buttons, and chip-type multilayer film capacitors as shown in FIG. They are also formed on the upper and lower surfaces and the left and right surfaces (side surfaces) near the end faces of the element.

In the resin mold type, the electrodes are formed by a lead frame, so the electrodes 2 at both ends of the element 13 are formed only on the element end face and the lower face near the element end face.

Let's consider this state and take an electrolytic capacitor as an example.
As shown in the figure.

Problems to be Solved by the Invention Chip-type electronic components are soldered (surface mounted) by a flow method, a reflow method, etc., but in recent years, soldering has become more difficult as the degree of integration has increased. That is,
As circuit patterns become finer, there is a problem in that when soldering, excess solder adheres to unnecessary parts, making short circuits more likely to occur.

This problem arises in chip-type multilayer ceramic capacitors, chip-type resistors, and chip-type multilayer film capacitors in which electrodes are formed not only on the element end face, but also on the top, bottom, left and right (side) faces near the element end face. This is particularly likely to occur with electronic components of this type.

This problem will be explained using drawings. Figure 7 a, b
11//i is a conventional multilayer ceramic capacitor with a land (made of copper foil) formed on a 12Fi substrate. For the sake of explanation, the width of the land is assumed to be the same as the element width. If the density is not as high as in Figure 7 B, even if excess solder remains, there will be no short circuit because the spacing between the elements is wide.
In the case of high density as shown in the figure, the extra half EIllI is likely to be connected by the solder wettability of the electrode on the side of the element, resulting in a short circuit.

SUMMARY OF THE INVENTION An object of the present invention is to provide a packaging method for chip-type electronic components that does not cause short circuits due to solder even when surface-mounted at high density.

Means for Solving the Problems In order to solve the above problems, the method for packaging a chip-type electronic component of the present invention includes the steps of: forming electrodes on the mother element, and then cutting the mother element into individual elements; The present invention is characterized in that it includes a step of applying a liquid resin only to both cut surfaces of the element formed by the cutting step using a gravure roller, and then curing the liquid resin.

Function: With the packaging method of the present invention, the side surface of the element of the electrode is coated with resin, so solder sometimes adheres to the side surface of the element of the electrode, and solder is not drawn into the side surface of the element, thereby preventing short circuits. It never becomes defective. Therefore, it is possible to realize a chip-type electronic component that is compatible with high-density surface mounting.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

As an example of the present invention, a chip-type multilayer film capacitor will be described. According to the manufacturing process of the laminated film capacitor, as shown in FIG. 3, a mother element 14 is cut by a cutting blade 15 to form individual capacitor elements. The cut surface 4 formed by cutting has the electrode end surface exposed, so it is covered with resin or the like so as not to deteriorate the capacitor characteristics.

FIG. 1 is a perspective view showing an example of a step of packaging a cut surface of a chip-type multilayer film capacitor with an ultraviolet curing resin. In FIG. 1, reference numeral 1 indicates a laminated film capacitor element, and reference numeral 2 indicates an electrode formed by metal spraying and solder plating on the electrode extension end face of the capacitor. An ultraviolet curable resin 9c is applied to a predetermined thickness on the cut surface 4 of the laminated film capacitor element using a gravure roller 8.

Here, the ultraviolet curing resin 9a is carried onto the gravure roller 8 by the scraping roller 7 and the intermediate transfer roller 6, and the excess resin 9b that does not fit into the gravure plate 3 is scraped off by the doctor blade 5. As shown in FIG. 2, since the resin is not attached to the non-plate portion of the gravure roller 8, the resin is applied only to the cut surface of the capacitor element, and the electrode end surface (arrow A' in FIG. 4) is coated only on the cut surface of the capacitor element. side)
It doesn't stick out. Ensure that the resin does not protrude from the electrode end surface! Soldering without loss of polar area is an important requirement to ensure properties.

As a result of examining various resin application methods, we found that application using a gravure roller is the best in this respect, and furthermore, by keeping the resin viscosity, resin temperature, application speed, etc. constant, the resin thickness can be maintained at a constant level with good reproducibility. It can be done.

The applied ultraviolet curable resin 9C is cured by irradiating ultraviolet rays with an ultraviolet lamp 10, and if necessary is thermally cured in a constant temperature bath or the like.

As shown in FIG.
The sides of the electrode (shown as B and B' in Figure 6) that are in the same plane as the cut surface are also coated, but the end faces of the electrode (shown as A and B' in Figure 6) are also coated. ) Ki
dResin is not protruding.

100 chip-type multilayer film capacitors invented by Tai
10 pieces in each row so that the side spacing is 0.6H,
They were arranged in 10 rows on a board and soldered using the flow method.

Note that the width of the land was made the same as the width of the element. As a comparative example, a chip-type multilayer film capacitor without the above-mentioned resin exterior was soldered at the same time. When observing the state after soldering, seven short circuits as shown in FIG. 7a were observed in the comparative example, but none occurred in the capacitor element of the invention.

As described above, in the Il-Rem capacitor of the present invention, short circuits due to solder do not easily occur between the wires of adjacent elements, so that high-density surface mounting can be performed by narrowing the spacing between the sides of the capacitor elements.

In addition, although the example of the film capacitor was shown in the above embodiment, the present invention is not limited to this, and ti may be formed not only on the element end face but also on the upper and lower surfaces and left and right surfaces (side surfaces) near the element end face. It can also be applied to chip 51Jit ceramic capacitors and chip type resistors. The exterior resin of the casing is not limited to the embodiments, and any liquid resin commonly used for the exterior of electronic components, such as thermosetting resin, can be used. Furthermore, the metal on the electrode surface is not limited to solder, and soldering can be expected to improve properties. For example, the object of the present invention can be achieved if it is coated with a metal containing tin.

Effects of the Invention As described above, according to the packaging method of the present invention, a chip-type electronic component that can be surface-mounted at high density can be realized without short-circuiting the electrodes of the chip-type electronic component.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of the step of sheathing the cut surface of a chip-type multilayer film capacitor according to an embodiment of the present invention using an ultraviolet curable resin, and FIG. 2 is a top view of essential parts in the same step.
Fig. 3 is a perspective view showing the cutting process of a multilayer film capacitor, Fig. 4 is an external perspective view of a multilayer film capacitor manufactured by the packaging method of the present invention, and Fig. 6 is an external appearance of a conventional chip type capacitor. FIG. 7 is a perspective view showing a state of a seventh factor a, bFi chip type capacitor after surface mounting. 1... Chip type multilayer film capacitor, 2.
・・・・Electrode, 3・・・・・・Gravure roller plate number, 4・・・・・・Cut surface % 5・・・Doctor blade, 6・・・・・・Intermediate roller, T...Kakiage roller, 8...Claviar roller, 9...
...Exterior resin, SA, SB, SC...UV curing resin, 10...UV lamp. Child love type! L Bottle Film Container No. 5 Figure Figure Figure // /2

Claims (4)

[Claims] (1) After the step of forming electrodes on the mother element, there is a step of cutting the mother element into individual elements, and using a gravure roller to apply liquid resin only to both cut surfaces of the element formed in the cutting step. A method for packaging a chip-type electronic component, comprising the step of curing the liquid resin after transfer coating. (2) In the process of applying resin to the cut surface of the element, liquid resin is applied onto the gravure roller, and after scraping off the excess resin that does not enter the plate of the gravure roller with a doctor blade, the resin is applied to the cut surface of the element. 2. The method for packaging a chip-type electronic component according to claim 1, wherein transfer coating is performed. (3) The method for packaging a chip-type electronic component according to claim 1, characterized in that the resin applied to the cut surface of the element is cured by ultraviolet rays. (4) The base layer of the electrode of the multilayer film capacitor as an element is formed by a metal spraying method, and the electrode surface is coated with solder or a metal containing at least tin. Exterior packaging method for chip-type electronic components.