JPH06140557A - Resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To increase an amount of plastic working and to improve flatness by lengthening the total length of an outer lead apparently without changing the distance between the tip of the outer lead and a sealing resin layer, and forming another part, which crosses the outer lead part that is guided to the orthogonal direction with respect to a mounting substrate at an acute angle. CONSTITUTION:An outer lead 2, which is guided to the outside from a sealing resin layer 1, is machined twice for surface mounting on a mounting substrate. Three parts are formed of a part, which is directed in the horizontal direction from the sealing resin layer 1, a first bent part 3, which is bent at an acute angle, and a second bent part 4, which is bent again comparatively gently. For the outer lead 2, nickel alloy is used as conductive metal. In the machining of the first bent part 3 and the second bent part 4, elastic working and plastic working are performed. The amount of the plastic working becomes large by the bending at an acute angle. Therefore, the spring-back characteristic becomes less, and the flatness is improved. The outer lead 2 has the jumping-up shape, and residual stress is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-sealed semiconductor device applied to surface mounting, and is particularly suitable for improving the outer lead shape led out from a sealing resin layer to the outside.

[0002]

2. Description of the Related Art In recent years, semiconductor devices with more and more integrated circuits having more than 200 pins have been put on the market, but the assembling process is not limited to the so-called tab system, but a system using a lead frame is still used. ing. The structure of a so-called sealing resin layer, that is, an envelope for protecting the semiconductor element mounted on the lead frame is QFP, SOP and D.
IP and the like are known, and many forms of the outer lead lead out from the sealing resin layer are also prepared for surface mounting.

FIG. 1 shows an outer lead (commonly known as a gull wing) of a resin-sealed semiconductor device for mounting an integrated circuit element.
The vertical angle θ ₂ (see FIG. 2) is standardized to 90 ° or more, that is, an obtuse angle, according to the specifications of the Japan Electronic Industries Association (EIAJ) and JEDEC in the United States. Along with this, the vertical angle θ ₂ is also obtusely shaped in products made by domestic and foreign semiconductor manufacturers.

In a resin-sealed semiconductor device using a lead frame in an assembly process, a semiconductor element is mounted on a bed portion installed on the lead frame, and then an electrode and a lead frame formed on the semiconductor element. A thin metal wire is crimped by wire bonding between the inner and outer leads of the frame to establish an electrical connection. Further, the semiconductor element is sealed by a trans-mold method to protect the semiconductor element from the external atmosphere, and the name of the inner lead led out to the outside of the sealing resin layer is outer.
Change to lead.

As is apparent from FIG. 1, the outer lead 2 led out of the sealing resin layer is bent twice in preparation for surface mounting. In the first bent portion 3, the outer lead 2 which is led out in the horizontal direction from the sealing resin layer 1 is bent downward by 90 ° or more, and then again at the second bent portion 4 located closer to the tip. Bending outward from the sealing resin layer 1 makes the first processing obtuse (see FIG. 2), but is standardized as described above.

FIG. 3 clarifies the standard value of the gull wing outer lead 2 in JEDEC.

[0007]

The outer lead clarified in FIG. 1 has a gull wing shape, and has the following problems in mounting. That is, the outer lead has become shorter with the miniaturization of the envelope, and the cushioning effect at the connecting portion between the outer lead and the mounting board has become smaller. This means that the difference in thermal expansion and the damage caused by vibration are alleviated. As the number of pins increases, the number of inner leads formed on the lead frame increases, and the pitch and width of the inner leads also decrease, so that external vibration and thermal stress It is easy to receive damage. Furthermore, the flatness is apt to be deteriorated due to a warp or the like caused by the enlarging and thinning of the sealing resin layer 1 in which the semiconductor element is embedded.

The present invention has been made under such circumstances, and it is an object of the present invention to improve the flatness of the outer lead.

[0009]

The resin according to the present invention is provided with another portion that intersects the lead portion extending from the encapsulating resin layer in a direction perpendicular to the mounting substrate at an acute angle. There is a feature of the sealed semiconductor device.

[0010]

The resin-encapsulated semiconductor device according to the present invention is mounted on the surface by increasing the apparent length of the outer lead without changing the distance between the tip of the outer lead and the encapsulating resin layer. Prepare For this reason, by forming a large number of portions that intersect the outer lead portion that is vertically drawn from the encapsulating resin layer with respect to the mounting substrate at an acute angle, the amount of processing plasticity is increased and flatness is improved. improves.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to FIGS. As is clear from each figure, the sealing resin layer 1
The outer lead 2 led out from the outside is processed twice for surface mounting on a mounting board (not shown).
That is, since it is bent at an acute angle at a portion extending from the sealing resin layer 1 in the horizontal direction and then at the position of the first bent portion 3 and further bent again at the second bent portion 4, 3 of a, b, c. It is divided into parts.

The outer lead 2 is connected to the portion a, and a dam bar 5 for the resin is formed by the resin sealing process so as to be transparent, and the tip of the outer lead 2 and the sealing resin layer 1 are formed. The distance between them is made exactly the same as the conventional size.

The standard for a and the remaining distance is 0.8: 1.
2, 0.8: 0.5, 0.3: 0.5 (unit: mm), which tends to become narrower, and the length of the outer lead 2 is 2,
It is as short as 1.3 and 0.3 mm.

In FIG. 2, the portion a is extended in the horizontal direction, but in the example of FIG. 3, it is extended slightly upward and then bent at an acute angle at the first bending portion 3. In this example, the b portion extends in the vertical direction, and the second bent portion 4 bends relatively gently, and the shape is almost the same as in FIG. However, the distance between the tip of the outer lead 2 and the sealing resin layer 1 is the same as in FIG.

FIG. 4 shows an example in which the bending strengths of the first bent portion 3 and the second bent portion 4 are both large, but the distance between the tip of the outer lead 2 and the sealing resin layer 1 is large. Is the same as in FIG.

By the way, the outer lead 2 is naturally made of a conductive metal, for example, an iron-nickel alloy. Therefore, although the elastic working amount and the plastic working amount are generated by processing the first bent portion 3 and the second bent portion 4, the plastic working is more difficult than the conventional obtuse angle forming by bending at the acute angle as described above. The amount increases. Along with this, the springback characteristic becomes smaller and the flatness is improved.

The embodiment shown in FIG. 5 is an outer reel.
Since the groove 2a has a shape that is higher than the sealing resin layer 1, it has an effect of removing the residual stress in the resin sealing step and the deburring step.

Further, since the outer lead 2b in the vertical direction is shaped at 90 ° with respect to the sealing resin layer 1, that is, the mounting substrate, it is easy to bend.

Further, in the embodiment shown in FIG. 6, the plastic working amount in the first bent portion 3 is increased to increase the degree of relaxing the damage from the outside. In addition, the outer that is directly inserted into the mounting board
Since the length of the lead 2c is increased, stable fitting is possible.

[0020]

In the resin-encapsulated semiconductor device according to the present invention, the distance between the encapsulating resin layer and the outer lead does not change, but apparently the length of the outer lead is large and external stress is applied. Effective in mitigation. Moreover, the outer is small in mounting area.
The shape of the lead is obtained, whereby the plastic working amount of the bent portion of the outer lead is large and the flatness is improved.

Further, since the outer lead portion in the horizontal direction from the sealing resin layer to the mounting board is long, the tamper is less likely to be bent, and stable bending is possible. Even then, stable mating is possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conventional resin-sealed semiconductor device.

FIG. 2 is a cross-sectional view showing a bent state of the outer lead shown in FIG.

FIG. 3 is an outer view of a conventional resin-sealed semiconductor device.
It is a figure which shows the standard value of a lead.

FIG. 4 is a sectional view of one embodiment of the present invention.

FIG. 5 is a sectional view of another embodiment of the present invention.

FIG. 6 is a sectional view of still another embodiment of the present invention.

[Explanation of symbols]

 1: sealing resin layer, 2: outer lead, 3: first bent portion, 4: second bent portion, 5: dam bar,

Claims (1)

[Claims] 1. A resin-sealed semiconductor device, comprising: a lead portion extending from a sealing resin layer in a direction perpendicular to a mounting substrate, and another portion intersecting an acute angle.