JPH0276290A - Mounting of chip component - Google Patents

Abstract

PURPOSE:To prevent improper soldering of chip components by printing ink protruding it like a bank surrounding the periphery of application position of an adhesive where a chip component is positioned and fixed and by soldering the chip component while applying a proper amount of adhesive to the inside. CONSTITUTION:A bank of ink 15 printed by protruding printing ink so that it surrounds a position for applying an adhesive within a range covered by a chip component 13 adhered to the position for applying the adhesive between both land parts 12, 12 of a printed circuit board 11 is built in a nearly circular form, a proper amount of adhesive 16 is applied to the inside, and then the chip component 13 is pressed to the adhesive 16 for adhesion. After that, the printed circuit board 11 is dipped in an automatic soldering tank for soldering. It allows solder 17, 17 which join each land part 12 and the chip component 13 properly to be formed and the chip component 13 to be mounted to the printed circuit board 11 without any improper soldering.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention provides a method for mounting chip components in which positioning and fixing of chip components using an adhesive is reliably performed, and soldering defects caused by adhesive liquid on the land portions are prevented. It is related to.

BACKGROUND OF THE INVENTION When chip components are mounted on a printed circuit board, the soldering properties of the chip components are often improved by fixing the chip components to the printed circuit board with an adhesive and then soldering them.

For example, FIGS. 9 to 12 show positioning and fixing of chip components using an adhesive in a conventional chip component mounting method. .4 is formed, and symbols, straight lines, etc. 3, which are indicators of the type of chip component 2 to be mounted or the mounting position, are printed on the surface of the substrate by silk screen printing. When bonding the chip components 2, first apply the adhesive 5.5 using the symbols, straight lines, etc. 3 printed at predetermined positions on the printed circuit board 1 as a guide, as shown in FIG.

Next, the chip component 2 is positioned at a predetermined position and placed on the adhesive 5.5, and is pressed and bonded (see FIG. 11 and 12). After bonding and fixing the printed circuit board 2 onto the printed circuit board 1, the printed circuit board 1 was sent to an automatic soldering bath (not shown) and soldered.

Problems to be Solved by the Invention However, in the case of the conventional mounting method described above, the adhesive 5
When the chip component 2 is placed on top and pressed down, the adhesive 5 extruded from the bottom surface of the chip component 2 ends up covering the land portion 4, and when soldering, the adhesive 5 of the land portion 4 sometimes covers the land portion 4. There was a problem in that soldering did not adhere to the solder parts, and defects occurred in soldering such as non-solder on the chip component 2 or insufficient solder adhesion area.

Therefore, the present applicant proposed a method for mounting chip components that forms a dam around the land as a method of preventing adhesive from covering the land (Japanese Patent Application No. 73754/1982).
. As shown in Figs. 13 and 14, this is done when printing the type of component to be mounted, the mounting position mark 6, or the mark 7°7 indicating the adhesive application position, etc. on the printed circuit board by screen printing. Ink is raised to surround the outer periphery of the land portion 8 to form a dam 9. Adhesive is applied at the position of the mark 7 indicating the adhesive application position, and aligned with the mark 6 of the mounting position. Then, the chip component 10 is pressed onto the adhesive to bond it.

At this time, the adhesive pressed onto the chip component 10 is
This prevents expansion in the direction of the land portion 8 and causes it to expand in directions other than the land portion 8.

Therefore, since the dam 9 is formed around the land portion 8, if the adhesive is accurately applied to the predetermined application position 7 and bonded, the land portion 8 will not be covered with the adhesive, and the chip component 1o can be fixed with adhesive. However, if the adhesive is applied away from the predetermined application positions @ 7, 7, that is, if it is applied to the position shown by the solid line in FIG. 14, the adhesive 7' will only spread slightly on the bottom surface of the chip component 10, the adhesive strength of the chip component 10 will be weak, and vibrations may occur when automatically inserting the lead component using an insert machine before soldering after bonding the chip component 1°. Accordingly, chip parts 10
There was a risk that it would peel off from the printed circuit board surface.

This invention was made against the above-mentioned technical background.
When soldering, ensure that the previous chip component is adhered to the printed circuit board, and avoid covering the land with adhesive.
The purpose of soldering chip components to a printed circuit board is to provide a method for mounting chip components that prevents the occurrence of defects.

Means for Solving the Problems As a means for solving the above-mentioned problems, the present invention provides a method for mounting chip components such as an FC or a resistor on a printed circuit board by electrically connecting them to the printed circuit board. Ink is printed in a dam-like manner to surround the area where the adhesive is applied to position and fix the chip components in areas other than the lands, and an appropriate amount of adhesive is applied inside the dam-like ink. It is characterized by applying the adhesive, pressing the chip components onto this adhesive, adhering and positioning them, and then soldering them.

Effect According to the above method, an ink dam is built around the adhesive application position on the printed circuit board, so after applying an appropriate amount of adhesive on the inside of this ink dam, this adhesive is When the chip component is pressed onto the adhesive, the adhesive pressed from above by the chip component is prevented from spreading outward by the ink dam, and is guided so as to spread over the entire application position along the inside of the dam. It spreads. Also, by restricting the outward expansion of the dam, it is prevented from covering the land portion. Therefore, the chip components are bonded with no adhesive covering the land portions and with a sufficient bonding area. After the chip parts are glued,
If soldering is performed in a soldering bath or the like, the chip components will be mounted without any soldering defects.

Embodiment The following is a first embodiment of the chip component mounting method of the present invention.
This will be explained based on FIGS. 8 through 8.

1 to 4 show the mounting method of the first embodiment of the method of the present invention in the order of steps, in which a plurality of land portions 12 are formed on the mounting surface of one printed circuit board, and a chip component 13 is formed on the mounting surface of one printed circuit board. For each pair of land portions 12.12 to which soldering is performed, a symbol, straight line, etc. 14 indicating the type of chip component 13 to be mounted and serving as an index of the mounting position is provided.
is printed by screen printing.

Both land portions 12.12 of the printed circuit board 11
The chip component 13 to be bonded is placed at the intermediate adhesive application position.
An ink dam 15 is printed by piling up the printing ink to surround this adhesive application position within the area covered by the adhesive.
is built in a roughly circular shape, and the inner area of the dam 15 is set to a size that provides sufficient adhesive force (first
(see figure). Further, the ink dam 15 is printed on the printed circuit board 11 by applying ink several times by screen printing, and is formed at a height that does not interfere with the soldering of the chip components 13.

Next, an appropriate amount of adhesive 16 is applied to the inside of the ink dam 15 constructed in a circular shape (see FIG. 2), and then the chip component 13 is pressed onto the adhesive 16 and bonded.

When the chip component 13 is pressed onto the adhesive 16, the adhesive 16 pressed from above by the chip component 13 spreads around. At this time, the spreading adhesive 16 is prevented from spreading to the outside of the ink dam 15, and spreads entirely along the inside of the ink dam 15, thereby preventing the adhesive 16 from covering the land portion 12. In this state, the chip component 13
(See Figure 3).

After bonding the chip components 13 to predetermined locations, if the printed circuit board 11 is immersed in an automatic solder bath (not shown) and soldered, each land portion 12 and the chip component 13 will not be covered with adhesive on the lands GL112. Solder 17.17 is formed to properly bond the chip components 13 to
The solder is mounted on the printed circuit board 11 without any defects (see FIG. 4).

Further, as shown in FIG. 5, when the chip component 13 is pressed in an inclined state, the adhesive 16 that tries to spread around the periphery first reaches the weir, as shown by the arrow in FIG. ! 1
After expanding toward the dam 5, the water flows around the dam 15, so that it does not flow out to the outside of the dam 15. Further, as shown in FIG. 7, when the adhesive 16 is applied to a position away from the center of the ink dam 15 formed in a circular shape, the adhesive 16 similarly spreads in the direction of each arrow. Therefore, a sufficiently large bonding area is ensured, and situations such as insufficient bonding area or insufficient amount of adhesive can be prevented.

FIG. 8 shows a second embodiment of the method of the present invention. In this mounting method, a circular ink dam 3
5, an overflow cut 36 is formed in a direction other than the direction of the land 12.12. Therefore, if the amount of adhesive 16 is not properly controlled and a large amount is applied, the excess adhesive will be pushed out from the cut 36 and spread in a direction that does not cause any problem, toward the land portion 12. prevent the spread of. Moreover, this cut 36 also serves as an air hole and becomes an escape route for the air inside the dam 35 when the chip component 13 is pressed, thereby improving the adhesion of the chip component 13.

Furthermore, by making the cut 36 formed in the ink dam 35 less than a certain width in relation to the viscosity of the adhesive 16, the adhesive 16 pressed against the chip component 13 first spreads throughout the inside of the dam 35. It is designed to overflow after expanding.

The ink used to form the ink dam 15°35 in both of the above embodiments is, for example, a normal marking ink, that is, a non-conductive ink prepared by adding a volatile solvent to a pigment, adhesive, etc. Although the ink is used, the present invention is not limited to this, and various other printing inks, whether conductive or non-conductive, as well as paints, adhesives, resin materials, and the like can be used.

As described in detail, the chip component mounting method of the present invention includes:
In a chip component mounting method in which chip components such as ICs and resistors are electrically connected and mounted on a printed circuit board, the area around the adhesive application position for positioning and fixing the chip components is applied to areas other than the lands on the printed circuit board. The ink is printed in a dam-like manner, surrounding it, an appropriate amount of adhesive is applied to the inside surrounded by the dam-like ink, and the chip components are pressed onto this adhesive to adhere and position them. Since soldering is used, soldering ensures that the previous chip component is firmly adhered to prevent it from peeling off from the printed circuit board, and also effectively prevents the adhesive from covering the land area, ensuring that the chip component is soldered without any defects. Can be implemented in the state.

[Brief explanation of the drawing]

Figures 1 to 4 show each step of the first embodiment of the method of the present invention, in which Figure 1 is a plan view of a substrate on which an ink dam is formed, and Figure 2 is a plan view of a substrate on which an adhesive is applied. Figure 3 is a front view showing the state in which the chip components are bonded, Figure 4 is the front view showing the soldered state, and Figure 5 is the front view showing the chip components tilted. Front view, No. 6
The figure is an explanatory diagram showing the direction in which the adhesive spreads when the chip component is pressed at an angle, Figure 7 is a plan view showing the direction in which the adhesive spreads when the adhesive application position is shifted, and Figure 8 9 is an explanatory diagram showing the second embodiment, FIGS. 9 to 14 show the conventional example, FIG. 9 is a plan view showing a state in which adhesive is applied, FIG. 10 is a cross-sectional front view, and FIG. 11 12 is a cross-sectional front view, FIG. 13 is a plan view of another conventional example with adhesive applied, and FIG. 14 is a plan view of the chip components adhered. FIG. 11... Printed circuit board, 12... Land portion, 13
...Chip parts, 15.35...Ink dam,
16...Adhesive, 17...Solder, 36...
break in the dam. Applicant: Toyota Motor Corporation Agent Patent Attorney: Kan 1) Kyuri (and 1 other person) Figure 1 Figure 2 Figure 4/13 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11

Claims (1)

[Claims] In a chip component mounting method in which chip components such as ICs and resistors are electrically connected and mounted on a printed circuit board, the area around the adhesive application position for positioning and fixing the chip components is applied to areas other than the lands on the printed circuit board. The ink is printed in a dam-like manner, surrounding it, an appropriate amount of adhesive is applied to the inside surrounded by the dam-like ink, and the chip components are pressed onto this adhesive to adhere and position them. A method for mounting chip components characterized by soldering.