JPS5889850A - Face mounting type semiconductor device - Google Patents

Abstract

PURPOSE:To manufacture the semiconductor device with structure in which a defective disconnection mode is difficult to be generated when face mounting by forming the device by a package and a plurality of leads and shaping through- holes or uneven sections to the leads. CONSTITUTION:A plurality of the leads 2 projected from both side surfaces of the package 1 consisting of resin are all projected downward on their midways, and the through-holes 6 are formed to the nose sections of each lead 2, solder welding regions from which solder leaks when mounting. Under a state that the package is mounted to a substrate (a wiring substrate), the nose sections of each lead are fixed to the substrate 4 by solder 5 under a state that the nose surfaces are opposed and placed to the substrate 4. The solder 5 intrudes into the through-hole 6 sections of the leads 2 at that time. Accordingly, contact areas among the leads 2 and the solder 3 are increased, adhesive strength is improved, the leads 2 are not stripped off from the substrate 4, and the defective disconnection mode can be reduced.

Description

[Detailed description of the invention] The present invention relates to a surface-mounted semiconductor device.

As one form of a semiconductor device, as shown in FIG. 1, one lead 2 is protruded from both sides of a package 10, and each lead 2 is bent halfway toward the bottom of the package 1. A distributed in-line type semiconductor device is known. When the semiconductor device 3 having this structure is mounted on a substrate such as a wiring board, the tips of the leads 2 extending downward are inserted into the insertion holes of the base plate and fixed with solder.

By the way, in recent years, as the mounting space has become smaller, the second
As shown in the figure, a so-called surface mount structure is adopted in which the leading end surfaces of the leads 2 are placed facing each other on the substrate 4 and fixed using solder 5.

However, since the conventional semiconductor device 3 is based on the assumption that the tips of the leads 2 are inserted into the insertion holes of the substrate, the tips of the leads 2 are chamfered and sharpened, as shown in FIG. There is. Therefore, the wI area of the solder gap with the adhesive material during mounting is small, and the bonding strength is low. Additionally, if the package is made of resin and the substrate is ceramic or paper phenol, thermal stress due to the difference in thermal expansion coefficient and number between the package and the substrate will be applied to the lead joint, causing the leads to separate from the substrate. As a result, a defect called a so-called disconnection mode is likely to occur.

Therefore, the purpose of this study is to provide a conductor device with a structure that is unlikely to cause disconnection mode failures during experiments.

In order to achieve such an object, the present invention comprises a package and a plurality of leads that protrude from the side surface of the package and extend bent toward the top or bottom surface of the package, and that are mounted on a substrate. In a surface mount "leakage semiconductor device" in which the lead end face faces the substrate surface and is fixed with an adhesive material, the
The solder welding area is provided with through holes or uneven portions, and the invention will be explained below with reference to Examples.

FIG. 4 is a perspective view of a semiconductor device according to an embodiment of the present invention, and FIG. 5 is a partial explanatory view showing the lead tips in a mounted state.

The cow conductor device shown in FIG. 4 is of a dual in-line type. That is, the plurality of glues 2 protruding from both sides of the package 1 made of resin are all downward (
protrudes upward). Further, a through hole 6 is provided at the tip of each lead 2, that is, in a solder welding region where solder gets wet during mounting.

When a semiconductor device having such a structure is mounted on a board (wiring board), each lead 2 is connected as shown in FIG.
The tip end is fixed to the substrate 4 with solder 5 with the tip surface mounted on the substrate (wiring board) 4. At this time, the solder 5 also enters into the portion of the through hole 6 provided in the solder welding area of the lead 2. As a result, not only does the contact area between the lead 2 and the solder 3 increase and the bonding strength improves, but also the solder 3 covers the lead tip through the through hole 6, so when the lead 2 is peeled off, it is difficult to In addition to peeling (shearing force) at the interface between the lead 2 and the solder 5, it is also necessary to cause tensile failure of the solder, and the bonding strength is significantly increased compared to the conventional method. Therefore, the leads 2 do not peel off from the substrate 4 even due to thermal stress in the temperature cycle test, and disconnection mode failures can be reduced.

Note that the present invention is not limited to the above embodiments. for example,
Figure 6 IJII, t (as shown in bl, lead 2
A groove 8 may be formed in the solder welding area (hatched area) 7 from the side or bottom surface to provide an uneven portion to improve the bonding strength with the solder.

Further, although the present invention has been described with respect to a dual in-line type, it can also be applied to a semiconductor device having a structure in which leads protrude from the entire circumferential surface of the package.Furthermore, the adhesive material may be other than solder.

As described above, according to the present invention, it is possible to provide a semiconductor device having a structure in which disconnection mode failures are less likely to occur during surface mounting.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional semiconductor device, FIG. 2 is a side view showing a surface-mounted state, FIG. 3 is a perspective view of a lead tip, and FIG. 4 is a surface-mounted device according to an embodiment of the present invention. FIG. 5 is an explanatory diagram showing the lead tips in a state where the semiconductor device is surface-mounted on a substrate, and FIG. 6
ll, (bl is a perspective view showing a lead tip in another embodiment. Single package, 2... Lead, 3... Semiconductor device, 4... Substrate, 5... Solder, 6) ...Through hole.

Claims (1)

[Claims] 1. Consisting of a package and a plurality of leads that protrude from the side surface of the package and bend and extend toward the top or bottom surface of the package, and when mounted on a board, A surface-mounted semiconductor device in which a lead end face faces a substrate surface and is fixed with an adhesive material, characterized in that a through-hole or an unevenness is provided in a solder welding area of each lead. . 2. A surface-mounted cover conductor device according to item 1 of the scope of special fraud, characterized in that the package is made of resin.