JPH06224357A - Resin sealed type semiconductor device - Google Patents

Abstract

PURPOSE:To securely exhaust absorbed water contents by integrating a hanging pin provided in connection with a bed portion and individual inner lead nearest the handing pin to form a wider area. CONSTITUTION:An inner lead 11 end is arranged around a bed portion 10 keeping a certain gap thereto and a fine metal lead 12 is extended like a constant loop between electrodes of a semiconductor element to be mounted and the inner lead 11. One handing pin 13 and one of the inner leads 11 corresponding thereto are reduced to form, on the contrary, a wider region 15 on the hanging pin 13. However, interval of the other inner leads 11 is not changed and exhaust areas of absorbed water contents are selected at the three positions a, b, c on the surface of the resin sealing layer. After a semiconductor is mounted on SOP lead frame providing such hanging pin 13 and the mold process is carried out to improve absorbed water content exhausting effect. Thereby, cracks which are caused by expansion of water contents within the sealing resin can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a resin-encapsulated semiconductor device, and is particularly suitable for a thin plane mounting resin-encapsulated semiconductor device.

[0002]

2. Description of the Related Art As a method for assembling semiconductor elements, a so-called tab is used, but a lead frame is also widely used. The lead frame type is selected according to the type of semiconductor element. To do. A lead frame for mounting a semiconductor device having an improved degree of integration is provided for a so-called multi-pin device by increasing the number of leads, and its shape will be described with reference to FIG. A metal plate body made of iron, an iron-Ni alloy, a clad material or the like is formed into a lead frame having a predetermined shape by etching or pressing. Although this shape differs depending on the type as described above, a plurality of unit bodies each having a bed portion 1 for mounting one semiconductor element in the substantially central portion are continuously formed, and the length is increased depending on the number of unit bodies. Distinguish whether it is short or short.

An inner lead 2 is provided around the bed portion 1 with a slight space therebetween, and a thin metal wire is provided between the electrode of the semiconductor element mounted on the bed portion 1 and the inner lead 2. 3 is stretched by a certain loop to prepare for connection with other electronic devices. In order to maintain the mechanical strength of the lead frame, it is common to provide a connecting strip on the surrounding frame and remove it after the resin sealing step. Further, after a series of steps, a transfer molding step, a so-called resin sealing step is performed to protect the semiconductor element from the external atmosphere, and the inner lead is led out of the sealing resin (outer lead and outer lead). Makes electrical connection to external electronic equipment.

As is apparent from the top view of FIG. 1, such a lead frame has a mechanical strength by fixing the bed portion 1 by means of suspension pins 4 starting from opposite positions of a frame (not shown). Is provided, and the distance from the inner lead 2 end arranged around it is relatively close. An active layer or a passive layer is formed in the semiconductor element, and a wiring layer electrically connected to the semiconductor layer is extended to the periphery to electrically connect with a so-called pad 5, and a thin metal wire is provided between the pad 5 and the inner lead. Three
Stretching is as described above (see FIG. 2). The number of hanging pins 4 is at least two.

[0005]

Among resin-encapsulated semiconductor devices, surface-mounting type devices are often used, and when mounting on the surface of other electronic equipment, an outer member shaped into a special shape is used. The lead is fixed to another electronic device via solder or the like, and the so-called reflow method is generally adopted for the fixing.

On the other hand, the bed portion formed on the lead frame has a substantially rectangular shape, and the pad 5 is provided on the short side of the bed portion, and the tip of the inner lead 2 is also arranged at a relatively close position. In other pin elements, many leads must be installed. Therefore, if the line space of the inner lead 2 is to be taken sufficiently, on the contrary, the width of the hanging pin 4 cannot be made too wide.

Therefore, the discharge effect is not sufficient. The drainage effect means an effect that moisture absorbed by both materials is discharged during the heating, that is, the reflow process due to a slight gap generated between the sealing resin and the metal forming the lead frame.

As described above, in the multi-pin element, the width and interval of the inner lead are narrowed and the width of the suspension pin 4 is also narrowed, so that the moisture is not sufficiently discharged. For this reason, the water expands during the reflow process and becomes a base for cracking the sealing resin layer.

The present invention has been made under such circumstances, and an object thereof is to provide a novel resin-sealed semiconductor device.

[0010]

Means for Solving the Problems A bed portion installed in a substantially central portion of a metal plate body, an inner lead arranged around the bed portion, a hanging pin connected to the bed portion, the hanging pin and the hanging pin Features of the resin-encapsulated semiconductor device according to the present invention in the wide portion for combining the single inner lead closest to the above, the semiconductor element mounted on the bed, and the encapsulating resin layer covering the semiconductor element. There is. Further, a wide portion starting from the bed portion, a plurality of end points from the wide portion exposed to the sealing resin layer, and a single external reel that constitutes the plurality of end points from the maximum width portion formed in the wide portion. There is also a feature.

[0011]

The metal layer constituting the lead frame has the effect of discharging the stored moisture through the slight gap formed between the lead frame and the sealing resin layer. A crack occurs in the envelope made of the resin blocking layer. The proof is that if the resin-encapsulated semiconductor device is dried at about 125 ° C. for 6 hours, p. p. It became clear that the weight decreased with the order of m. That is, when the resin-encapsulated semiconductor device is put in a moisture absorption oven kept at a humidity of 60% and a temperature of 85 ° C. for 168 hours, 1000 p. p. The present invention has been completed based on the fact that the weight decreases with the order of m, and is particularly suitable for a planar mounting type resin-sealed semiconductor device.

[0012]

Embodiments of the present invention will be described with reference to FIGS. Both figures are top views after mounting the semiconductor element on the lead frame. SOP (Small Out Lin)
ePackage) A resin-sealed semiconductor device will be described.

As is apparent from FIGS. 2 and 3, the SOP
The lead frame used for the resin mold semiconductor device
A metal plate body made of iron, an iron-Ni alloy, and a clad material is formed into a predetermined shape by an etching or pressing process. Although this shape differs depending on the type of the resin-encapsulated semiconductor device, the bed portion 1 for mounting one semiconductor element
Is provided in a substantially central portion, and a plurality of these are continuously provided to discriminate whether the length is long or short.

Around the bed portion 10, the inner lead 11 ends are arranged at a slight distance, and a thin metal wire 12 is fixed between the electrode of the semiconductor element to be mounted and the inner lead 11. It is useful for tensioning with a loop and prepared for connection with other electronic devices. In order to maintain the mechanical strength of such a lead frame, the inner lead 12
In general, a so-called connecting strip (not shown) is provided on the surrounding frame body, which is the starting point, and is removed after the resin sealing step.

After a series of mounting steps, a transfer mold step or so-called resin encapsulation step is performed to protect the semiconductor element from the external atmosphere, and the inner lead 12 is covered with the encapsulation resin. To establish electrical connection with external electronic equipment.

As is clear from the top view of FIG. 1, such a lead frame has a mechanical strength by fixing the bed portion 1 by means of a hanging pin 13 starting from a position opposite to a frame body (not shown). Inner to be placed around it
The distance from the end of the lead 11 is relatively small.

On the other hand, in the semiconductor element, a specific impurity is diffused by an ordinary process to form an active layer or a passive layer, and a wiring layer electrically connected to this is extended to the periphery and electrically connected to a so-called pad 5. The pad 14 and inner
The thin metal wire 12 is stretched between the leads as described above. The number of hanging pins 13 is at least two.

However, in the present application, the hanging pin 13 and the inner pin are used.
The relationship of the lead 12 is different from that of the prior art. That is, as is apparent from FIGS. 3 and 4, the number of the hanging pin 13 on one side and the inner lead for the hanging pin 13 is reduced by one, and conversely, the wide portion 15 is formed on the hanging pin to remove the moisture absorbed. Increase.

However, the spacing of the other inner leads is the same as that of the conventional one, and the outlets thereof are at three points a, b and c on the surface of the sealing resin layer (not shown). After the semiconductor element is mounted on the SOP lead frame equipped with the suspension pins 13, a so-called transfer (abbreviation of Transfer Mold) process is performed to complete the resin-encapsulated semiconductor device. Is improved.

Further, in a model in which the pad 14 formed on the semiconductor element to be mounted and the inner lead 12 closest to the hanging pin 13 are not electrically connected, as shown in FIG. -The tab 12 and the hanging pin 13 are combined to form the wide portion 15 having a larger width than in the case of FIG.
Specifically, if the portion left after the inner lead 12 is cut off is integrated with the hanging pin 13 as shown by the dotted line in FIG. 4, a wide portion 15 having a larger width than in the case of FIG. 3 is obtained. . As a result, the contact area with the encapsulating resin layer is increased, and the discharge effect is increased as compared with the example of FIG.

[0021]

In the lead frame for mounting the resin mounting type semiconductor device of the plane mounting type, the hanging pin having a large area cannot be formed if the line space of the inner lead is sufficiently taken. Moisture absorption could not be sufficiently discharged in the reflow process in the mounting process. However, in the surface-mounting resin-sealed semiconductor device according to the present invention, since the wide portion is formed by integrally forming a part of the inner lead with the hanging pin, it is possible to reliably discharge the absorbed moisture, and thus the moisture is not absorbed. It is possible to prevent cracks caused by expansion in the sealing resin.

[Brief description of drawings]

FIG. 1 is a top view of a conventional lead frame.

2 is a top view showing a state in which a pad of a semiconductor element mounted on the lead frame shown in FIG. 1 and an inner lead are connected by a thin metal wire.

FIG. 3 is a top view of a resin-sealed semiconductor device according to the present invention during an assembly process.

FIG. 4 is a top view of another embodiment of the present invention during a resin-encapsulated semiconductor device assembly process.

[Explanation of symbols]

 1, 10: Bed part, 2, 11: Inner lead, 3, 12: Thin metal wire, 4, 13: Hanging pin, 5, 14: Pad, 15: Wide part, a, b, c: Exit.

Claims (2)

[Claims] 1. A bed portion installed in a substantially central portion of a metal plate, an inner lead arranged around the bed portion, a hanging pin provided in connection with the bed portion, the hanging pin and a single piece closest thereto. A resin-encapsulated semiconductor device comprising: a wide portion provided by combining the inner leads of the above; a semiconductor element mounted on the bed; and a sealing resin layer covering the semiconductor element. 2. A wide portion starting from the bed portion, a plurality of end points from the wide portion exposed in the sealing resin layer,
A resin-encapsulated semiconductor device comprising: a single external lead forming the plurality of end points from the maximum width portion formed in the wide portion.