JPH0430745B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a lead frame having a group of lead terminals for attaching a main body of an element such as a semiconductor element and a strip plate portion for transportation.

<Prior Art> As shown in the plan view of FIG. 5, a conventional lead frame has a pair of parallel strips 1, 1 and two groups of lead terminals connected to the strips. After attaching an element body to each group of two groups of lead terminals, this element body is molded with resin to form a molded part 3. In this way, the entire lead frame having the resin molded part 3 is connected to the strip part 1,
The lead terminal 2 is subjected to a series of transfer processes using the lead terminal 1, various treatments are performed during this transfer process, and finally the lead terminal 2
is separated from the strip parts 1, 1, and the resin mold part 3 with lead terminals 2 is taken out as a single IC, and only the feed holes 4 of a constant pitch are formed in the strip parts 1, 1. was.

<Problems to be Solved by the Invention> However, in the conventional lead frame having such a configuration, after the element body is resin-molded, heat shrinkage occurs as the resin in the resin molded part 3 cools, and the The contraction force is the lead terminal 2
The compressive stress is transmitted to the strip plate portion 1 via the tie bar 5 connecting the lead terminal 2 and the strip plate portion 1, and compressive stress acts on the strip plate portion 1. Therefore, the band plate part 1 warps,
It may be curved or wavy, which may hinder the transfer of the strip part 1 in subsequent processing steps, reducing productivity, or worsening the accuracy of workpiece positioning, resulting in a decline in quality. It was hot.

On the other hand, in order to eliminate the distortion of the band plate part 1 due to heat shrinkage as described above, it has been considered to form slits in staggered shapes at appropriate positions of the band plate part 1, and the present application proposes The lead frame has already been filed for an invention related to the lead frame.
However, since the slits are formed in the direction perpendicular to the strip plate part 1, the strip plate part 1 tends to stretch due to the tensile force during transportation, and may be unintentionally stretched during the punching or plating process. There was a risk that the feeding protrusion would not fit into the feeding hole 4, causing trouble in transfer, or positioning would become inaccurate, causing various problems in subsequent processing steps and producing defective products.

The present invention has been made in view of the above-mentioned problems, and it suppresses warping, curving, and waving of the band plate portion after resin molding, and also suppresses warpage of the band plate portion that may occur due to the formation of slits. The purpose is to prevent unexpected stretching, ensure that transport and positioning can be performed accurately as expected, and prevent the occurrence of defective products.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides a group of lead terminals connected to each other from a pair of parallel strips, and attaches an element body to the group of lead terminals. attachment,
In the lead frame in which the element body is subjected to a resin molding process, at an appropriate position of the band plate part,
A pair of slits are formed in a staggered manner from the inner and outer edges of the band plate part, and the cutting direction of the slits is diagonal to the longitudinal direction of the band plate part.

<Function> Due to the slits formed in the strip part of the lead frame diagonally with respect to its longitudinal direction, the strip part shortens in response to stress in the compressive direction, absorbs distortion during thermal contraction, and resists tensile force. In this case, the tensile force is divided into the depth direction and the width direction of the slit, and the component force in the direction of expanding the slit is reduced, so it is difficult to stretch compared to a material with a simple slit, and it may not stretch unexpectedly. Transfer and positioning after resin mold processing can be performed accurately.

<Example> Hereinafter, the present invention will be described in detail based on an example shown in the drawings. The plan view of FIG. 1 shows a lead frame according to the present invention, and the basic structure is the same as that of the conventional example, and parts corresponding to those of the conventional example of FIG. 5 are given the same reference numerals. That is, the lead frame includes a pair of strip plate parts 1, 1 parallel to each other,
This has two groups of lead terminals connected to each other, and after each of the two groups of lead terminals is attached to the element body, the element body is subjected to a resin molding process to form the resin molded part 3. be done. Therefore, in the present invention, a pair of slits 6, 6 are formed in the band plate part 1 at a location corresponding to the middle of the resin mold parts 3, 3 arranged in parallel at a constant pitch.

The slits 6, 6 are cut from the inner and outer edges of the strip plate part 1 in a staggered manner and are formed obliquely with respect to the longitudinal direction of the strip plate part 1.

The inclination directions of the slits 6 are the same inclination direction so as to be parallel between each pair of slits 6, but may be made to be different for each pair of slits 6, as shown in FIG. Further, the slits 6 may be provided as a pair, one inside and one inside, or one slit 6 may be formed into a plurality of slits 6, as shown in FIG. The location and number of slits 6 to be formed may be appropriately selected depending on the degree and distribution of thermal contraction of the resin molded portion 3.

In the above configuration, thermal contraction occurs as the resin cools after the resin molding process, and compressive stress acts in the longitudinal direction of the strip plate portion 1 in response to this.
There is a slit 6 in the strip portion 1, and as the slit 6 deforms into a narrower shape, the compressive stress is absorbed by the slit 6, so the strip portion 1 does not deform. , does not cause warping, curving, or waving phenomena.

Furthermore, during the transportation of the lead frame having the element body, a tensile force is applied in the longitudinal direction of the strip plate portion 1, and the tensile force Fo is applied to the slit 6 as shown in the explanatory diagram of FIG. It is divided into a component force Fa in the depth direction of the slit 6 and a component force Fb in the width direction of the slit 6, and the component force Fb in the width direction of the slit 6 acts to widen the width of the slit 6.

By the way, in the case where the slits are simply formed in the direction perpendicular to the strip plate part 1, the entire tensile force acts in the direction of widening the width of the slits, but in the present invention, a part (Fb) of the tensile force Fo is applied to the slits 6. Since it only acts in the direction of widening the width of the strip, it is difficult for the strip portion 1 to stretch, and it will not stretch unexpectedly due to the tensile force during transportation.

<Effects of the Invention> As described above, according to the present invention, the slits formed in the strip section obliquely with respect to the longitudinal direction absorb compressive stress caused by thermal contraction of the resin molded section, and the strip becomes smoother. In addition to reliably suppressing the warping, curving, and waving phenomena of the plate part, the part with the slits is difficult to deform under tensile force, so there is no chance of the strip part stretching unexpectedly during transportation. Transfer and positioning can be performed accurately, and generation of defective products can be prevented.

[Brief explanation of drawings]

FIG. 1 is a plan view of one embodiment of the present invention, FIGS. 2 and 3 are plan views of other embodiments, and FIG.
The figure is an explanatory view of the operation, and FIG. 5 is a perspective view of a conventional example. DESCRIPTION OF SYMBOLS 1...Strip plate part, 2...Lead terminal, 3...Resin mold part, 6...Slit.

Claims (1)

[Scope of Claims] 1. A lead frame in which a group of lead terminals is connected from a pair of parallel strips, an element body is attached to the group of lead terminals, and a resin molding process is applied to the element body. In this method, a pair of slits are formed at appropriate positions in the band plate part in a staggered manner from the inner and outer edges of the band plate part, and the cutting direction of the slits is diagonal to the longitudinal direction of the band plate part. Characteristic lead frame. 2. The lead frame according to claim 1, wherein the inclination direction of the slits is different for each pair of slits. 3. The lead frame according to claim 1, wherein one of the pair of slits has a plurality of slits.