JPH0714961A - Manufacture of resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To efficiently keep the directionality of an outer lead by a method of adopting such technique that a mold step of the outer lead is performed in a condition that it is connected to a coupled fine stripe, to remove the coupled fine stripe. CONSTITUTION:A semiconductor element is mounted to a metallic supporter and a metallic coupled fine stripe 12 is arranged in the direction crossing a plurality of inner leads arranged in this metallic supporter to connect the plurality of inner leads to each other. Also, this inner lead is electrically connected to a semiconductor element, which is coated with a sealing resin layer 10 to lead a plurality of outer leads 11 to an external unit. In particular, a mold step for bending the outer lead 11 positioned between the coupled fine stripe 12 and the sealing resin layer 10 is performed and the coupled, fine stripe 12 is removed thereafter. Accordingly, even if the mold angle of the outer lead 11 is high, the specific direction can be kept without spoiling the directionality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of molding an outer lead which is led out from a resin layer covering a semiconductor element, and is particularly suitable for a bending process of the outer lead.

[0002]

2. Description of the Related Art As a method of assembling a semiconductor device, a method utilizing a so-called tab or lead frame is known, and the latter is still widely used. As the material of the lead frame, iron or iron-nickel alloy, copper or copper alloy, and a metal clad with these materials are used and formed into a predetermined shape. This predetermined shape is finished by a pressing or etching process, but there are many types in which the number of leads is increased or decreased according to the degree of integration and the thickness is reduced as the number of bins increases. In such an assembly method using a lead frame, a so-called mounting step, a bonding step, a resin molding step by a transfer mold, a so-called bending step, that is, a bending step and an outer plating are performed. Process Further, the product is sorted by characteristic inspection before shipping. Further, the lead or inner lead formed on the lead frame is named as an outer lead, which is led out to the outside of the sealing resin. , QFP and other types are known.

On the other hand, as a field of application of the resin-encapsulated semiconductor device, there is a surface mounting type assembling method, and the outer lead can be molded at various angles according to the type of electronic equipment adopting the same. Is required.

FIG. 1 used for explaining the bending step is a top view showing a main part of a resin-sealed semiconductor device, and FIG. 2 is a side view thereof.

As described above, the resin sealing layer 1 for protecting the semiconductor element from the external atmosphere, as shown in FIG. 1, leads out a plurality of outer leads 2 to prepare for connection with electronic equipment. However, as shown in FIG. 2, the bending angle may be large, and the vicinity of its upper end should be bent by 90 ° so that it can be inserted into an electronic device.

Further, in the lead frame, in order to maintain the mechanical strength of each lead and maintain its directionality, a so-called tie bar, which is also called a connecting strip 3, is arranged in a direction orthogonal to the lead direction. It is installed and the installation position is set to each outer lead portion relatively close to the sealing resin.

In the molding process, an upper die punch and a lower die which form a die are used, and a curved portion corresponding to an angle formed on the outer lead 2 is formed on the upper die and the lower die. A predetermined bend is formed on the outer lead 2 which is formed in a female relationship, and the upper die punch is lowered to be placed on the lower die.

When the angle formed by such a series of bending steps, that is, the forming step is large, a method is adopted in which the angle is made small once and then made another predetermined angle. Further, this forming step is usually performed after cutting the connecting strip 3.

[0009]

When the outer lead is formed at a large angle by the bending process using the upper die punch and the lower die forming the die as described above, the connecting strip 3 is cut. It is customary to do this after removal. However, the outer lead is bent in the lateral direction crossing the outer lead, and the directionality is often deteriorated.

The present invention has been made under the above circumstances, and provides a method of manufacturing a resin-sealed semiconductor device capable of maintaining the directionality of the outer lead in a good condition.

[0011]

A process of mounting a semiconductor element on a metal support, and a metal support provided in a direction intersecting a plurality of inner leads installed on the metal support. The process of connecting each other by connecting strips,
A step of electrically connecting the inner lead and the semiconductor element; a step of covering the semiconductor element with a sealing resin layer to lead out a plurality of outer leads to the outside; Molding of an outer lead for a resin-sealed semiconductor device according to the present invention in a molding step of bending an outer lead portion located between sealing resin layers and a step of removing the connecting strips after this step. There is a feature of the method.

[0012]

As described above, the outer lead molding method of the present invention employs a method of removing the connecting strip after the connecting strip is connected to the connecting strip, so that the outer lead is formed. Even if the angle is large, the predetermined direction can be maintained without impairing the directionality.

[0013]

Embodiments of the present invention will be described with reference to FIGS. 3 to 8 show a series of steps, and FIG. 9 is an enlarged view after the molding step performed on the outer lead,
Further, FIG. 10 is an external view of a resin-sealed semiconductor device completed by these examples.

In the resin-sealed semiconductor device, the type of lead frame to be applied is selected depending on the model, and the material is iron or iron-nickel alloy, copper or copper alloy, and a metal clad with these materials, It is used as a predetermined shape by a pressing process or an etching process. In addition, the number of leads is increased or decreased in accordance with the degree of integration of semiconductor elements, and the thickness is often reduced as the number of pins increases. In such an assembly method using a lead frame, a so-called molding step is performed after a so-called mounting step, a bonding step and a resin sealing step.

In the case of a resin-sealed type semiconductor device used for electronic equipment as a surface mount type, a molding process is performed on the outer lead in preparation for automatic insertion, but the angle is large or small depending on the user's request. Is.

The method of the present invention is suitable for carrying out a molding process with a small angle or a large angle, and FIG. 3 shows a main part of a resin-sealed semiconductor device after the resin-sealing process. In the figure, an outer member is drawn from one surface of the rectangular parallelepiped sealing resin layer 10.
The state where the leads 11 are connected by the connecting strips 12 will be clarified. Further, an upper die punch having a curved portion corresponding to an angle formed on the outer lead 2 in a male-female relationship and a lower die 1 (neither are shown) are prepared, and the lower die is shown in FIG. After arranging the outer lead 11 as shown, the even-numbered outer lead 11 is pressed by the lowered upper die punch to bend the portion a to about 30 degrees as shown in FIG. The strip 12 was cut and its top view is shown in FIG.
The lines shown in FIGS. 3, 5, 6 and 8 in the direction intersecting the longitudinal direction of the outer lead 11 indicate the approximate positions where the molding process is performed.

Next, as shown in FIG. 7, a molding step of about 90 degrees with respect to the linear direction is performed near the tip b of the outer lead 11 after this molding step, for example, for electronic equipment during surface mounting. Ready for insertion.

Next, as shown in FIG. 7, the odd-numbered outer lead 11 is subjected to a deeper molding step than the a portion as shown in FIG. A resin-encapsulated semiconductor device as described above is obtained. In addition, as described above, the tip portion b is also subjected to the forming step of bending at 90 degrees,
For surface mounting, for example, to prepare for insertion into an electronic device.

The angle of such a forming process is shown in FIG. That is, the forming process of the even-numbered outer lead 11a portion is an angle θ _{1 of} about 30 °, the forming process of the odd-numbered outer lead 11c portion is an angle θ _{2 of} about 60 °, and the forming process of both b portions. Is approximately θ ₃ right angle.

Even-numbered and odd-numbered outer leads 11
Has a pitch of, for example, 1.27 mm, and the outer lead 11 which has completed the molding process for the parts a and c and the molding process for the part b
The distance between them is, for example, 5.08 ± 0.3 mm, and the dimension of the outer lead 11 straight part d after the molding process of the b portion is, for example, 4.35 ± 0.2 mm, the outer lead. 11
The diameter is 0.75 ± 0.05 mm.

Further, the distance d between the a portion and the b portion and the distance between the c portion and the b portion may differ depending on the design of the electronic device and the like. Therefore, when the distance d is relatively small, the influence of the stress formed in each portion. To avoid this, it is preferable to make the distance between the connecting strip 12 and the portion b larger than when the distance d is relatively large.

[0022]

As described above, in the method of manufacturing the resin-sealed semiconductor device according to the present invention, the outer lead is cut from the tip portion after the final molding step, so that the outer lead is cut at a predetermined angle. When it is bent, its tip is connected to the connecting strip. Therefore, the directionality of the outer lead after the molding process is improved, so that the outer lead can be fitted in a predetermined position during surface mounting.

[Brief description of drawings]

FIG. 1 is a top view of a conventional resin-sealed semiconductor device after an outer lead molding step.

FIG. 2 is a side view of an outer lead of the resin-sealed semiconductor device shown in FIG.

FIG. 3 is a view of a resin-encapsulated semiconductor device according to the present invention.
It is a top view which shows the state which completed a part of molding process of a lead.

FIG. 4 is a side view showing the resin-sealed semiconductor device after the step of FIG.

FIG. 5 is a top view of the resin-sealed semiconductor device, which shows a state after cutting the even-numbered outer leads from the connecting strips after the molding step shown in FIG. 3;

FIG. 6 is a top view of the resin-sealed semiconductor device after the odd-numbered outer lead molding step.

7 is a side view showing the resin-sealed semiconductor device after the step of FIG.

FIG. 8 is a top view of the resin-sealed semiconductor device from which the connecting strips have been removed after the entire molding process.

FIG. 9 is a cross-sectional view showing the dimensions of the resin-sealed semiconductor device in the outer lead molding step.

FIG. 10 is a top view of the resin-encapsulated semiconductor device after all the steps are completed.

[Explanation of symbols]

 1, 10: resin sealing layer, 2, 11: outer lead, 3, 12: connecting strips, a to c: outer lead portion for performing molding step, d: between ac for performing molding step The distance.

Claims (1)

[Claims] 1. A step of mounting a semiconductor element on a metal support, and a metal connecting strip provided in a direction intersecting with a plurality of inner leads installed on the metal support. A step of connecting each other, a step of electrically connecting the inner lead and the semiconductor element, and a step of covering the semiconductor element with a sealing resin layer to lead out a plurality of outer leads to the outside. And a molding step of bending an outer lead portion located between the connecting strip and the sealing resin layer, and a step of removing the connecting strip after this step. Method for manufacturing semiconductor device