JPH01276790A - Reflow soldering method of chip component - Google Patents

Abstract

PURPOSE:To prevent a solder ball from being produced toward the lower side of a chip component by printing soldering paste only on the outside from a position of the center of the electrode of the chip component placed on a pattern, and reflow-soldering the printed soldering paste. CONSTITUTION:Soldering paste 5 is printed only on the outside from a position of the center of the electrode 4. Then, the parts 3 are placed thereon and subjected to reflow soldering. Hereby, a soldering ball can be prevented from being produced toward the lower side of the parts 3, so that soldering ball removal operation is eliminated in the reflow soldering operation, to make unnecessary a soldering ball removal work in a reflow soldering of the component 3 and hence make effective the reflow soldering work.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for preventing the formation of a large number of solder balls under a chip component during the process of reflow soldering the chip component to a pattern on a ceramic substrate. The present invention relates to a reflow soldering method.

[Conventional technology]

First, a conventional reflow soldering method will be briefly explained using FIGS. 3, 4, and 5. FIG. 3 is a diagram before reflow soldering, and FIG. 4 is a sectional view of FIG. 3. FIG. 5 is a sectional view after reflow soldering. In the figure (
1) is a ceramic substrate.

(2) is a conductor pattern fired on the ceramic substrate (1).

+31 Fi chip component, (4) is melted at the electrode part of chip component (3), (51 solder paste is melted by reflow soldering equipment and the chip component is mounted. A is solder fillet, B is solder ball. be.

Next, the reflow soldering procedure will be explained.

On the ceramic substrate (1) on which the pattern (2) has been fired, solder paste (5) is printed on the entire surface of the pattern (2) where the chip component (3) will be placed, using a mesh screen. 3) and place it on the reflow soldering device. 70 - The solder paste (5) is melted by the heat of the soldering device and the chip component (3) is soldered.

[Problem to be solved by the invention]

In this method, the tip part (
The solder paste (5) that swelled inward due to the pressure when 3) was placed on the ceramic substrate (1) is blown away by the activation of the flux, and a large number of solder balls B are formed at the temperature at which the solder melts. Therefore, as shown in Fig. 5, the phenomenon that the solder ball B remains under the chip component (3) is likely to occur, which will later cause insulation defects due to the solder balls, so prevent the occurrence of insulation defects due to the solder balls. To do this, use the pattern (
The solder ball must be removed with something thinner than 2).

The problem was that it took a lot of time.

This invention was made to solve the above-mentioned problems, and provides a reflow soldering method that eliminates the need to remove solder balls and contributes to improving the efficiency of reflow soldering work. .

[Means for Solving the Problem] The reflow soldering method according to the present invention is such that solder paste is printed only on the outside from about half the position of the electrode of the chip component to be placed on the pattern, and reflow soldering is performed. be.

[For production]

In this invention, when reflow soldering a chip component to a conductor pattern on a ceramic substrate, generation of solder balls on the underside of the chip component is prevented.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings.

1 and 2 show an example of the reflow soldering method according to the present invention, and FIG. 2 is a sectional view of FIG. 1. In the figure, solder paste (5) is printed only on the outside from about half the position of the electrode (4) of the chip component (3).

The above-mentioned approximately half position is a value discovered as a result of experiments to determine at what position on the electrode (4) good reflow soldering can be performed. For example, if the solder paste (51) is printed in a large size, solder balls may occur, and if it is printed in a small size, it will not be possible to form a good fillet. Printing the solder paste (5) on the screen of the mesh that can be printed in such a position is considered to be best, and after placing the chip component (3), reflow soldering as usual. Attach.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to eliminate the need for solder ball removal work in the reflow soldering work of chip components, thereby greatly contributing to the improvement of work.

[Brief explanation of the drawing]

1 and 2 are diagrams for explaining the reflow soldering method of the present invention, and FIGS. 3, 41, and 5 are diagrams showing the conventional reflow soldering method. In the figure, tl+ is a ceramic substrate, and (2) is a conductor pattern. (3) is a chip component, (4) is an electrode portion of the chip component (3), and (5) is a solder paste. Note that in the two figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] In the method of reflow soldering a chip component to a pattern on a ceramic substrate, in order to prevent the formation of many solder balls on the underside of the chip component, solder paste is only applied outward from about half of the electrodes of the chip component. A reflow soldering method for chip components, characterized in that after printing, the chip components are reflow soldered to a pattern on a ceramic substrate.