JPH03239393A - Solder land for chip component - Google Patents

Abstract

PURPOSE:To prevent the generation of Manhattan phenomena and facilitate visual inspection of the quality of soldering by forming a land projection section which extends from chip components so that the width may be narrowed compared with the land width of a land main body which responds with a soldered part of the chip component. CONSTITUTION:A pair of solder lands 11 which respond with a pair of soldered parts of a chip component 3 is formed on a substrate in projected shape. The solder lands 11 are formed so that the land width 13w of a projected part 13 which extends from the chip component 3 may be narrowed in contrast with the land width 12w of a land body 12 formed in the same shape with the soldered part 4 of the chip component 3. Therefore, a Manhattan promotion moment based on the surface tension of molten solder acting between the soldered part 4 of the chip component 3 and the land projection part 13 of the solder land 11 is reduced by a reduced portion of the land width 13. In addition, the moisturized state of the solder land 11 is confirmed at the land projection part 13. This construction makes it possible to prevent the generation of Manhattan phenomena and facilitate visual inspection of the quality of soldered parts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a solderland for chip components used when soldering chip components onto a substrate.

(Prior Art) As shown in FIG. 5, most of the solder lands for chip components formed on the substrate 1 are square solder lands 28.

In some cases, an elliptical solder land 2b as shown in FIG. 6 is also used.

When such a conventional solder land is used, as shown in FIG. 7, a Manhattan phenomenon (component standing phenomenon) in which the chip component 3 stands up on the substrate 1 may occur.

This Manhattan phenomenon occurs when the protruding land length S of the solder land 2 protruding from the chip component 3 is large, and the inner molten solder 6a is Since the Manhattan promoting moment B based on the surface tension of the outer molten solder 6b is larger than the Manhattan suppressing moment A based on the surface tension etc., in order to prevent this Manhattan phenomenon, it is necessary to adjust the land protrusion length. It has already been reported in "Electronic Materials" December 1988 that it is sufficient to shorten S.
Shown in the monthly issue.

(Problem to be Solved by the Invention) Therefore, although shortening the land protrusion length S is effective in preventing the Manhattan phenomenon,
If the land protrusion length S is simply shortened, the land protrusion 2s of the solder land 2 will be hidden under the solder joint 6, as shown in FIG. 8, and the land protrusion 2s will become wet. There is a problem in that it is not possible to visually inspect whether or not the solder is present, and it is difficult to confirm from the shape of the solder joint.

In this way, for inspection purposes, it is desirable to ensure a constant land protrusion length as well as to prevent the Manhattan phenomenon.

The present invention has been made to solve these problems, and an object of the present invention is to provide a solderland for chip components that can prevent the Manhattan phenomenon and that allows easy inspection and confirmation of soldering quality. It is something.

(Structure of the Invention) (Means for Solving the Problems) The present invention provides a solder land for chip components to which a chip component 3 is soldered. 32 land width 1
These solder lands for chip components are formed in such a manner that the land protrusion protruding from the chip component 3 + the land width of 3.23.

(Function) The present invention provides the soldering portion 4 of the chip component 3 and the land protruding portion of the solder land 11.21.31 +3°23,3
The Manhattan acceleration moment based on the surface tension of the molten solder acting between the land widths 13w and 23w
, 33w is reduced by the amount that is narrowed.

Also, the wetness of the solder land is determined by the land protrusion +
3. Confirmed on 23.33.

(Example) Hereinafter, the present invention will be explained in detail with reference to the example shown in FIGS. 1 to 4.

As shown in FIGS. 1 and 2, a pair of solder lands 11 corresponding to a pair of soldering parts (electrode parts) 4 of the chip component 3 are formed in a convex shape on the substrate 1, respectively.

This solder land 11 has a land width 12W of a land body 12 formed in the same shape as the soldering part 4 of the chip component 3.
In contrast, the land protruding portion 1 protruding from the chip component 3
The land width 13v of No. 3 is formed narrowly. Further, the relationship between the length +2L of the land body 12 and the protrusion length Iff[, of the land protrusion portion 13] is +21, ≧+3L. Furthermore, the land bodies 1 of the pair of solder lands 11
2 is provided so as to correspond to the total length 3L of the chip component 3.

Then, as shown in FIG. 2, when soldering is performed between the soldering part (electrode part) 4 of the chip component 3 and the solder land 11, the soldering part
and the land protruding portion 13 of the solder land 11,
A Manhattan acceleration moment based on the surface tension of the molten solder acts, but as the land width 13w becomes narrower,
Since the area of action of molten solder surface tension is reduced, the Manhattan promoting moment is reduced. Further, the degree of wetting of the solder land is confirmed by the solder joint 6 formed on the land protrusion 13.

FIG. 3 shows a solder land 21 showing another embodiment of the present invention, in which the land width 23 of the land protruding portion 23 is
The width is gradually narrowed so that w decreases proportionally.

FIG. 4 shows a solder land 31 showing yet another embodiment, in which the land width 33w of the land protruding portion 33 is 32w compared to the land width 32w of the land body 32 located under the chip component.
It is formed to become gradually narrower so that it decreases in a quadratic curve.

Then, each embodiment shown in FIGS. 3 and 4 is
As the land widths 23w and 33v gradually become narrower, the area of action of the surface tension of the molten solder related to the Manhattan promotion moment (area of the land protruding portions 23 and 33 protruding from the chip component 3 in FIGS. 3 and 4)
is reduced, so the Manhattan promotion moment is reduced.

In this way, all solder lands in which the width of the land protrusion protruding from the chip component is narrower than the land body below the chip component are included in the present invention, regardless of their shape.

〔Effect of the invention〕

According to the present invention, the land width of the land protruding portion protruding from the chip component is narrower than the land width of the land body corresponding to the soldering portion of the chip component, so the Manhattan promoting moment is reduced compared to the conventional solder land. Since the Manhattan phenomenon can be prevented and a clear land protrusion can be formed, the quality of the soldering (whether it is wet or not) can be easily visually inspected at this part.

[Brief explanation of drawings]

FIG. 1 is a plan view showing one embodiment of the solder land of the present invention, FIG. 2 is a perspective view of a chip component soldered on the solder land, and FIG. 3 is a plan view showing another embodiment of the present invention. FIG. 4 is a plan view showing still another embodiment of the present invention,
Fig. 5 is a plan view showing a conventional solder land, Fig. 6 is a plan view showing another conventional solder land, Fig. 7 is a cross-sectional view of a soldering part of a chip component showing the Manhattan phenomenon, and Fig. 8 is a plan view of a chip component. FIG. 3 is a cross-sectional view of the soldered state. 3. Chip parts, 4. Soldering part, 11°21,
31...Solder land, 12.22.32...Land body, 12w, 22w, 32w...Land width,
13.23゜33... Land protrusion, 13w,
23w, 33w...Land width.

Claims (1)

[Claims] (1) In a solder land for chip components to which chip components are soldered, the land width of the land protruding part that protrudes from the chip component is narrower than the land width of the land body corresponding to the soldering part of the chip component. A solderland for chip parts characterized by: