JPS63296360A - Semiconductor device - Google Patents

Abstract

PURPOSE:To reduce the fraction defective of molding at the time of resin molding by a method wherein second plane parts retreated from the lower surface part of a resin-sealing part are provided on the peripheries of the end parts of the lower surface part. CONSTITUTION:A semiconductor element 31 is mounted on a lead frame, is resin-sealed and thereafter, outer leads 33 of the lead frame are bent in a J form. Moreover, second plane parts 37 retreated from a lower surface part 38 of a resin-sealing part 36 are provided on the peripheries of the end parts of the lower surface part 38. As the plane parts 37 are constituted without irregularity, irregularities are reduced in a metal mold for resin molding. Thereby, defective moldings are decreased. Moreover, a cleaning becomes easy to execute at the time of assembly of a printed circuit board.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a resin-sealed semiconductor device.

[Summary of the invention]

In the present invention, the outer lead is bent into a J shape, and
The present invention relates to a semiconductor device characterized by having a second plane part recessed from the lower surface part around the end of the lower surface part of the resin sealing part.

[Conventional technology]

A conventional semiconductor device having an outer lead bent into a J shape has a shape as shown in Japanese Unexamined Patent Publication No. 58-27354. That is, in FIGS. 2 and 3, a plurality of convex portions 4 and a plurality of concave portions 5 were provided on the lower surface portion 2 of the resin sealing portion l, corresponding to the plurality of outer leads 3. The outer lead 3 is embedded in each side surface 6 of the resin sealing part l, and
It was bent into a shape, and the other end went over the convex part 4 and entered the concave part 5. When resin-sealing a shape having a large number of convex portions 4 and concave portions 5 as described above, the molding rate tends to deteriorate due to resin debris and the like, and the defective rate tends to increase. The situation will be explained with reference to FIG.

In FIG. 4, reference numeral 10 denotes an upper mold having an upper cavity 11 that forms the product shape. 12 is a lower mold, which has a lower cavity 13 which becomes a product shape. The lower cavity 13 has protrusions 14 and depressions 15 that will become the recesses 5 and protrusions 4 of the product. Resin is injected from the runner 1G through the gate 17 into the upper and lower cavities IL13. 18 is a lead frame.

In the case of resin molding, it is a well-known fact that it is difficult to eliminate the gap at the boundary between the upper mold 10 and the lower mold 12, and that a minute gap of about 5 μm is created.

For this reason, the molding resin enters this gap and hardens, and after opening the upper mold lO1 and lower mold 12 and taking out the product, the above-mentioned
A portion of the thin (about 5 μm) resin that has entered the gap adheres to the product and is removed from the upper mold 10 and lower mold 12, and a portion adheres to or falls to the upper mold 10 and lower mold 12 and is left behind. To remove this, after molding, use air or a brush to remove the upper mold 10.
, the thin resin left behind in the lower mold 12 is removed.

At this time, if there are irregularities mainly in the upper and lower cavities 11 and 13 of the upper mold 10 and the lower mold 12, a thin hardened resin 19 tends to remain at the base of the protrusion 14 and the bottom of the depression, and the next time the resin is injected, It is also a well-known fact that the cured resin 19 is mixed into the product, which tends to cause quality problems.

From the above point of view, in the conventional method, there were many fine irregularities corresponding to the outer leads 3, and it was difficult to remove the cured resin.

Further, as shown in FIG. 5, the product according to the present invention is assembled onto a substrate 21 by soldering 20 onto a substrate 21. As shown in FIG.

During soldering, flux is used to activate the fixed portion, and after soldering, the flux adhering to the resin sealing portion 1 and the like is removed using a solvent.

According to the conventional method, the resin sealing part 1 has many irregularities, and the flux gets into it, making it difficult to clean with a solvent, and if it remains, there is a risk that the outer lead 3 will rust due to the characteristics of flux. was there.

Further, a convex portion 4 and a concave portion 5 are provided corresponding to the outer lead 3.
is provided, and the tips of the outer leads 3 are placed inside the recess 5, so in conventional semiconductor devices, the number of outer leads 3 that can be installed is determined by the design of the initial resin sealing part l. Therefore, only one type of mold can be used to mold the resin sealing part 1.

[Problem that the invention seeks to solve]

As described above, according to the conventional method, the thin hardened resin is difficult to remove even by blowing with air due to the many irregularities of the resin molding special mold, increasing the defective rate of the product. Since there are many fine irregularities on the surface, it has the disadvantage that it is difficult to remove flux when assembling it onto a printed circuit board.

However, the present invention is intended to solve the conventional problems, and its purpose (1) is to reduce the defective rate during resin molding.

(2) Easier flux cleaning when assembling printed circuit boards (and improves quality).

(3) A plurality of types of semiconductor devices can be supplied using one resin molding mold.

[Means for solving problems]

The present invention is a semiconductor device characterized in that a second plane part recessed from the lower surface part is provided around the end of the lower surface part of the resin sealing part.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 and 6. FIG.

30 is Guibat, 31 is a semiconductor element, Guibat 3
It is fixed at 0. 32 is a metal inner lead,
Reference numeral 33 denotes an outer lead which is formed integrally with the inner lead 32. Reference numeral 34 denotes a thin wire having a diameter of about 30 μm, which electrically connects the inner lead 32 and an unillustrated electrode of the semiconductor element 31. 35 is the tip of the outer lead 33, 36 is a substantially square resin-sealed portion, and 37 is drawn in from the lower surface 38 of the resin-sealed portion 36, all around the four sides of the lower surface 38 of the approximately square resin-sealed portion 36. A second plane portion 39 located at 39 indicates the arrangement interval of the outer leads 33.

〔Effect of the invention〕

According to the above configuration, since the second plane 37 is configured without the unevenness shown in the conventional example, the resin molding mold has fewer unevenness (therefore, there are fewer molding defects, as described above). It is also clear that cleaning is easy when assembled onto a splint board.

Furthermore, since the second plane 37 is formed without any unevenness, the arrangement interval 5 is not limited, so the number of outer leads 33 can be selected within a technically possible range. - As an example, if the external dimensions of the resin sealing part 36 are 29°3m/m in length and width, the number of outer leads 33 is arranged at an arrangement interval of 39°.
If is 1, 27+++n+ then 84 lines 1.27/2+m
In this case, 160 pieces can be arranged, and multiple types of semiconductor devices can be obtained even with one type of molding die.

In the embodiment of the present invention, the case where the second plane 37 is completely flat on all four sides has been explained, but the protrusion 40 may be provided near the apex of a substantially square shape as shown in FIG. is also possible. The height of this protrusion 40 is
8, and may be lower or higher than the lower surface portion 38.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the present invention Fig. 2 is a side view showing a conventional method Fig. 3 is a lower plane showing a conventional method Fig. 4 is a sectional view showing resin molding 6 is a bottom plan view showing one embodiment of the present invention; FIG. 7 is a top plan view showing another embodiment 30...Guibat 31...Semiconductor element 32 . . . Inner lead 33 . Applicant: Seiko Epson Co., Ltd. Coffin 3: 6 Nagi

Claims (2)

[Claims] (1) In a semiconductor device in which the outer leads of the lead frame are bent into a J shape after a semiconductor element is mounted on a lead frame and resin-sealed, a lower surface portion is placed around the end of the lower surface portion of the resin-sealed portion. A semiconductor device characterized by having a second flat portion that is more retracted. (2) In the semiconductor device according to claim 1, which has a resin sealing portion having a square or rectangular planar shape, the second planar portion protrudes near the apex of each side of the square or rectangle. A semiconductor device characterized by having a part.