JPH04171972A - Lead frame - Google Patents

Abstract

PURPOSE:To easily execute a plating treatment after a forming and bending operation by providing a connection member which is inserted between a part near a semiconductor-element mounting part in a lead part and an outer- circumferential frame and which connects both electrically. CONSTITUTION:The base part of each support stay 10 is expanded to be a V-shape; one side is connected to the base part of lead parts 2 at the right end of a side on the left side and the other side is connected to the base part of lead parts 2 at the left end of a side on the right side. The connection states are maintained even when a forming and bending treatment is executed. The bending treatment is executed to a part which is situated forward from the part of the lead parts 2; and the bending treatment is not executed to the part of the V-shape. The support stay 10 is not separated form the lead parts 2. The lead parts 2, 2, ... inside each side are in a mutual continuity relationship by a tie ber 3. Consequently, it is possible to apply an electric current to all the lead parts 2, 2, ... via an outer-circumferential frame part 6, and an electric current for plating use can extremely easily be applied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a lead frame that can easily prevent the occurrence of scratches and cracks.

[Prior Art] A lead frame composed of a semiconductor element mounting portion and a large number of leads connected to the semiconductor element is generally plated with noble metal or solder.

Here, FIG. 8 is a plan view showing the shape of the partition part of a general lead frame. In the figure, lead parts 2, 2... are arranged around the semiconductor element mounting part 1, and the tips of the lead parts 2, 2... connected by.

Further, the bases of the lead parts 2, 2, . . . are connected to each feeding can by a dam 4. A semiconductor element (not shown) is mounted on the semiconductor mounting part 1, and then connected to the bases of the lead parts 2, 2, . . . by wire bonding and molded.

FIG. 9(A) is a perspective view of the lead frame after the molding process has been performed, and 5 is a mold resin portion in which a semiconductor element is molded. Further, as shown in the figure, a plurality of lead frames are continuously formed. And the ninth
From the state shown in Figure (A), the state shown in Figure (B) is reached through the resin removal process to remove excess mold material and the dam cut process to cut the dam 4. In this state, plating processing (solder, tin, Precious metal plating, etc.) is performed. Next, as shown in FIG. 9(c), the lead parts 2, 2...
. . . The forming and bending process is performed, and then each lead frame is taken out and the process is completed.

[Problems to be Solved by the Invention] By the way, as mentioned above, after plating, the lead portion 2,
When performing the forming bending process of 2..., a problem arose in that the surface of the mold came into contact with the plating surface during forming bending, causing problems such as rubbing, scratches, and cracks. Such hindrances not only spoil the appearance, but also
This also adversely affects the solder adhesion during mounting.

Therefore, the present inventors created a processing method in which plating processing is performed after forming and bending processing. However, conventional lead frames were created on the premise that forming bending would be performed after plating, so when forming and bending was performed, each lead part would become independent for a long time, and the mold resin Each side viewed from the other side becomes electrically independent. Therefore, it becomes necessary to supply power to each lead part or each canister individually.
A problem arose in that the plating process became complicated. For example, in the type shown in FIG. 8, when the forming bending process is performed, the branch part a and the lead part 2 are separated, and each side becomes electrically independent. This means that unless the branch part a of the stay extending from the outer peripheral frame branch part 6 is cut from the lead part 2, the lead part 2 cannot be formed and bent.

The present invention has been made in view of the above-mentioned circumstances, and is characterized by providing a lead frame that can be easily plated even after forming and bending.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a semiconductor element mounting portion, a lead portion extending from the semiconductor element mounting portion, and a portion around the semiconductor element mounting portion. In a lead frame having an outer circumferential frame section that is arranged in series on the same plane, a connecting member that is inserted between the vicinity of the semiconductor element mounting section of the lead section and the outer circumferential frame section and electrically connects the two. It is characterized by comprising the following.

[Function] Even if the lead portion is bent, the part that is actually bent is the tip of the semiconductor mounting portion, and the lead portion,
Since the outer peripheral frame portion and the connecting member are on substantially the same plane, their connection relationship is maintained even after bending. Therefore, even after bending, electricity can be applied through the outer peripheral frame portion, and plating can be easily performed.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

(1) Shape of Example FIG. 1 is a perspective view showing the shape of the lead frame in this example, and FIG. 2 is a sectional view thereof. These figures show the state at the time the frame bending process is completed.

In FIGS. 1 and 2, 10 is a support stay whose base is divided into a V-shape. One side of the figure 7 shape is connected to the base of the lead part 2 at the right end of the left side, and the other is connected to the base of the lead part 2 at the left end of the right side. These connection states are maintained even after the forming bending process is performed. This is as shown in Figure 2.
This is because the bending process is performed on the part beyond the base of the lead part 2, and the bending process is not performed on the 7-shaped part, so that the support stay 10 and the lead part 2 are not separated.

Further, the lead portions 2.2, . . . in each feeding direction are electrically connected to each other by tie bars 3 as shown in FIG. Therefore, it is possible to energize all the lead parts 2, 2, .

(2) Machining process in this example FIGS. 3A to 3E are perspective views showing the lead frame manufacturing process in this example. In addition, in the figures, parts corresponding to those in FIGS. 8 and 9 described above are designated by the same reference numerals, and explanations thereof will be omitted.

3(a) to 3(c) are processes corresponding to the respective parts shown in FIG. 9 described above, including resin removal, dam force, throat and lead forming bending.

However, in the state shown in FIG. 3(b), the lead portion 2,
2... Do not perform plating. In this embodiment, the plating process is performed in the state shown in FIG. 3C, that is, after the forming and bending process.

Here, FIG. 4 is a sectional view showing the positional relationship between the mold resin part 5 and the outer peripheral frame part 6 when performing the plating process, and as shown in the figure, the outer peripheral frame 6 and the base of the support stay 10 are on the same plane. It is in.

Next, as shown in FIG. 3(D), after plating, a tie bar cut is performed, and the support stay 10 is cut and taken out (see FIG. 3(E)).

By performing the processing according to the above process, the following effects can be obtained.

■Since the plating layer is formed according to the bent shape,
No scratches or cracks will occur on the surface of the bent part.

- The solder film thickness can be freely controlled in the lead part, and it is also possible to achieve segregation by making the tip thicker and the base thinner.

■When performing solder plating, the component ratio of 5u-Pb can be freely controlled.

(2) In addition to solder plating, the above processing method can also be used for gold plating and other noble metal plating.

(3) Modification Next, a modification of this embodiment is shown in FIGS. 5 and 6.

The one shown in FIG. 5 is of a type in which supporting stays 15 are provided along the lead parts 2 at the ends of each side, and the tips of these supporting stays 15 are connected to the bases ( (closer to the mold side than the dam). According to such a configuration, the supporting stay and the lead portion 2 maintain the connected state even after the forming bending process for the same reason as in the above case. Here, the seventh
The figure shows the relationship between the outer circumferential frame and the base of the lead part 2 after the bending process, but as shown in the figure, these are on the same plane, so they are not separated. Therefore, it is possible to conduct electricity through the outer frame 6 to all the lead portions 2 2 .

Next, the one in Figure 6 is of the type in which the base of the support stay is formed in a 7-shape, almost the same as the one shown in Figures 3 and 4, but the center part of the support stay is This is an example where the shapes are different.

[Effects of the Invention] As explained above, according to the present invention, a connecting member is provided which is inserted between the vicinity of the semiconductor element mounting portion of the lead portion and the outer peripheral frame portion and electrically connects the two. , electricity can be easily applied during the plating process after forming and bending.

Therefore, the solder surface of the lead part may be rubbed, scratched, cracked,
The occurrence of wrinkles etc. can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the configuration of an embodiment of the present invention, Fig. 2 is a side sectional view of the lead frame shown in Fig. 1, and Figs. 3 (a), (b), (c), (d). , (e) are process diagrams for explaining the processing method in this embodiment, Fig. 4 is a side view showing the positional relationship of each part during plating processing in the same embodiment, and Figs. 5 and 6 are the same. FIG. 7 is a side view of the lead frame shown in FIGS. 5 and 6 during metal plating processing; FIG. 8 is a plan view showing the shape of a conventional lead frame; FIG. 9 is a process diagram for explaining a conventional lead frame processing method. 1...Semiconductor mounting part, 2...Lead frame (lead part), 3...Tie bar, 6...
...Outer frame part, 10...Support stay (
connection member).

Claims (1)

[Scope of Claims] A semiconductor device mounting portion, a lead portion extending from the semiconductor device mounting portion, and an outer peripheral frame portion continuous on substantially the same plane around the semiconductor device mounting portion. A lead frame, comprising: a connecting member inserted between a vicinity of the semiconductor element mounting portion of the lead portion and the outer peripheral frame portion and electrically connecting the two.