JPH09121012A - Semiconductor lead forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable reduction in frequency of cleaning a bending die, increase in operating rate and productivity, and improvement in quality of products. SOLUTION: A semiconductor lead tip portion 2a of a semiconductor package 1, which has a semiconductor lead 2 bent in advance to have a curved tip portion and to have a J-shape as a whole, is formed in an end-curved shape by using a bending die 3 having a forming portion 4 corresponding to a semiconductor lead tip portion 2b after forming. With this semiconductor package 1 supported at a fixed position, the bending die 3 and the tip portion 2a of the semiconductor lead 2 are abutted against each other, and the bending die 3 is turned in the direction of curving the lead.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a semiconductor lead molding method for molding in a letter shape.

[0002]

2. Description of the Related Art J-shaped bending is known as one of the bent shapes of semiconductor leads in a semiconductor IC package. Conventionally, a method of ironing bending has been adopted for this J-shaped bending.

When a semiconductor lead is bent in a J shape, it is usually preliminarily bent into a J shape so that the tip portion has a gentle curved shape, and then the tip portion has a steeper final curved shape. The main bending is done like this.

FIG. 4 is an explanatory diagram of a method of performing a main bending by a method of ironing a semiconductor lead that has been pre-bent. In FIG. 4, (a) is a diagram showing a state before the main bending, and (b) is a diagram showing a state after the main bending. Further, in FIG. 4, 41 is a semiconductor package, 42 is a semiconductor lead, 43 is a bending die, 44 is a molding part, 45 is a knockout plate, 42a is a semiconductor lead tip part which has been bent by pre-bending, and 42b is a final bending part. This is the tip of the semiconductor lead in a curved state. The surface of the semiconductor lead 42 is pre-plated with solder.

According to the method of ironing and bending, the semiconductor package 41, in which the semiconductor leads 42 are pre-bent, is positioned on the bending die 43, and a pressing device (not shown) is driven to push down the knockout plate 45. Bending die 4 with a gentle bend on the tip side of lead 42
By squeezing the surface of the molding portion 44 of No. 3, the main bending is performed to make the shape of the curved portion into a steeper final bending shape.

However, according to the above-mentioned conventional method, the J-shaped bending of the semiconductor lead can be performed with a device having a simple structure, but the semiconductor lead 4 is formed on the surface of the molding portion 44 of the bending die 43.
Since the gently curved portion 2 is squeezed to form a steeper final curved shape, the solder plated on the surface of the semiconductor lead 42 tends to be rubbed and easily peeled off.
For this reason, the solder that has peeled off adheres strongly to the molding portion 44 of the bending die 43, and the bending die must be frequently cleaned, resulting in difficulties in operating rate and productivity. Further, there has been a problem that due to the narrowing of the pitch between the leads of the semiconductor leads and the like, the scraps of the solder that have fallen off come into contact with the leads, resulting in poor quality.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art as described above, and it is possible to reduce the frequency of cleaning the bending die, improve the operation rate and the productivity, and achieve the product. It is an object of the present invention to provide a method for molding a semiconductor lead capable of improving the quality of the above.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, the semiconductor lead tip portion of the semiconductor package having the semiconductor lead tip portion formed into a curved shape and having a semiconductor lead that is pre-bent so as to have a J shape as a whole is formed into a semiconductor lead tip after molding. A method of forming a final curved shape by using a bending die having a forming portion corresponding to a portion, wherein the bending die and a tip of a semiconductor lead are brought into contact with each other while the semiconductor package is supported at a fixed position. Then, a semiconductor lead molding method is provided, which comprises rotating the bending die in a lead bending direction. Further, according to the present invention, there is provided a semiconductor lead molding method as described above, characterized in that the bending die is brought into contact with the vicinity of a bending start point on the outside of the tip bending portion of the semiconductor lead. Further, according to the present invention, there is provided a semiconductor lead molding method characterized in that, in the above, a bending die in which an edge is formed at an end point corresponding to the lead root side of the molding portion is used.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The semiconductor lead molding method of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram illustrating the principle of the method of the present invention. In the figure, 1 is a semiconductor package, 2 is a semiconductor lead, 3 is a bending die, 4 is a molding portion, 5 is an edge of the molding portion 4, 6 is a fixing member, and 2a is a semiconductor lead tip portion in a curved state due to pre-bending. Reference numeral 2b is a tip of the semiconductor lead which is in a final curved state due to the main bending.

In the present invention, the semiconductor lead 2 of the semiconductor package 1 which has been pre-bent by a known method.
Is the object of molding. That is, the semiconductor lead 2 before molding is preliminarily bent so that the tip portion 2a thereof has a gentle curved shape as shown by a chain double-dashed line in the figure and has a J shape as a whole. Main bending is performed on such a molding object under the following conditions. (1) Support the semiconductor package 1 at a fixed position. (2) As the bending die 3, as shown in the figure, one having a molding portion 4 having a curved shape corresponding to the tip of the semiconductor lead after molding is used. Therefore, the curved shape of the molding portion 4 must be larger than the curved shape of the pre-bent semiconductor lead tip portion 2a. (3) The edge 5 of the bending die 3 is brought into contact with the tip 2a of the semiconductor lead 2. (4) With the semiconductor package 1 side fixed, the bending die 4 in the lead bending direction (arrow A in the figure) centering on the contact point.
Rotate to.

According to the semiconductor lead molding method of the present invention,
Since the J-shape is formed by rotating the bending die, the curved portion of the semiconductor lead that has been solder-plated in advance is not bent by bending, but is bent by rolling with respect to the bending die. Scarcely wears off. Therefore, the number of times of cleaning the bending die can be significantly reduced, and the operating rate and productivity of the molding apparatus can be increased. Further, the adhesion of solder dust to the product is eliminated, the quality of the product is improved, and the yield is improved.

[0012]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the present invention happens to use a link mechanism, and it is also possible to use a cam or a motor drive, etc. The invention is not limited to the embodiments illustrated here.

2 and 3 are explanatory views of an embodiment of a semiconductor lead molding apparatus to which the method of the present invention is applied. FIG. 2 shows a state before molding and FIG. 3 shows a state after molding. This example is an example in which the bending die is rotated in conjunction with the movement of the mold to perform molding. Reference numeral 11 in the drawing denotes a pressing member connected to an upper die (not shown) of a mold set in the press device, and is configured to move up and down as the press device is driven. The lower end 12 of the pressing member 11 is the first contact portion 1 of the cams 13A and 13B.
It is in contact with 4A and 14B. The cams 13A and 13B are pivotally supported by the support shafts 15A and 15B so as to be rotatable.
Second contact parts 16A, 16B in addition to the contact parts 14A, 14A
have. On the other hand, two cylindrical pins 19a, 19a '; 19b, 19b' are horizontally provided on the upper side wall of the die plate 18 installed on the lower die 17 of the die, respectively, to form a bending die. It engages with slots 20A, 20B formed near the center of 3A, 3B. Here, the positional relationship and shape of the cylindrical pins 19a, 19a '; 19b, 19b' and the positional relationship and shape of the slots 20A, 20B are such that the bending dies 3A, 3B rotate by a certain angle around the edges 5A, 5B. Stipulated in. The lower ends 21A and 21B of the bending dies 3A and 3B are cams 13
The second contact portions 16A and 16B of A and 13B are engaged with each other.

Next, the operation will be described. When a semiconductor lead is molded by using the above apparatus, first, the semiconductor package 1 in which the semiconductor leads 2A and 2B are pre-bent is put in a proper position in a mold installed in the press machine as shown in FIG. As described above, it is fixed and held by a fixing member (not shown). That is, at this time, the edges 5 of the bending dies 3A and 3B
A and 5B come into contact with the vicinity of the bending start point (P, P ') on the outside of the curved portions of the semiconductor leads 2A and 2B, and the respective curved portions are in a state of having entered the molding portions 4A and 4B of the bending dies 3A and 3B. ing. When the press device is driven from this state to move the pressing member 11 downward, the lower end 12 of the pressing member 11 urges the first contact portion 14A of the cam 13A and the first contact portion 14B of the cam 13B downward. As a result, the cam 13A rotates counterclockwise about the support shaft 15A and the cam 13B rotates clockwise about the support shaft 15B. Due to this rotation, the second contact portion 16A of the cam 13A urges the lower end portion 21A of the bending die 3A in the clockwise direction, and the second contact portion 13B of the cam 13B causes the lower end portion 2 of the bending die 3B.
Energize 1B counterclockwise. Then, the bending dies 3A and 3B are moved (rotated) by the cylindrical pins 19a, 19a '; 1 provided on the left and right of the upper side wall of the die plate 18.
Since it is regulated by 9b and 19b ', the bending dies 3A and 3B rotate clockwise and the edges 5A and 5B of the molding portions 4A and 4B of the bending dies 3A and 3B contact the points P and P', respectively. It rotates counterclockwise by a certain angle and becomes the state as shown in FIG. By the movement of the bending dies 3A and 3B, the semiconductor leads 2A and 2B are finally bent into a desired shape.

[0015]

According to the present invention, the following remarkable effects can be obtained. (1) Compared with the conventional molding using the ironing and bending method, the tip of the semiconductor lead, which is pre-solder-plated, is rolled and bent with respect to the bending die, so that the scraping of the solder hardly occurs. Therefore, the number of times of cleaning the bending die can be significantly reduced, and the operating rate and productivity of the molding apparatus can be increased. (2) Solder residue does not adhere to the product, the product quality is improved and the yield is improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the principle of a semiconductor lead molding method according to the present invention.

FIG. 2 is a side view showing a state before molding of a semiconductor lead molding apparatus to which the method of the present invention is applied.

FIG. 3 is a side view showing a state after molding of the semiconductor lead molding apparatus to which the method of the present invention is applied.

FIG. 4 is an explanatory diagram of a method of performing main bending by a method of ironing bending on a semiconductor lead that has been preliminarily bent.

[Explanation of symbols]

1 Semiconductor package 2, 2A, 2B
Semiconductor leads 3, 3A, 3B Bending dies 4, 4A, 4B
Molding part 5, 5A, 5B Edge 6 Fixing member 11 Pressing member 12 Tip 13A, 13B Cam 14A, 14B
First contact portion 15A, 15B Support shaft 16A, 16B
Second contact portion 17 Mold lower die 18 Die plate 19a, 19a ', 19b, 19b' Cylindrical pin 20A, 20B Slot 21A, 21B
lower end

Claims (3)

[Claims] 1. The tip has a curved shape and is entirely J
The semiconductor lead tip portion of the semiconductor package having the semiconductor lead pre-bent into a letter shape is molded into a final curved shape by using a bending die having a molding portion corresponding to the molded semiconductor lead tip portion. A method for forming a semiconductor lead, characterized in that the bending die and a tip portion of a semiconductor lead are brought into contact with each other while the semiconductor package is supported at a fixed position, and the bending die is rotated in a lead bending direction. Method. 2. The method for molding a semiconductor lead according to claim 1, wherein the bending die is brought into contact with the vicinity of a bending start point on the outer side of the tip bending portion of the semiconductor lead. 3. The method for molding a semiconductor lead according to claim 1, wherein a bending die having an edge formed at an end point corresponding to the lead root side of the molding part is used.