KR20000013177A - Lead forming die having double forming area - Google Patents

Abstract

PURPOSE: A lead forming die is provided to prevent a spring-back phenomenon and a stripping phenomenon of a lower and an upper dies using a first and a second forming areas. CONSTITUTION: The die comprises a lower die on which a semiconductor package is placed and an upper die in which a cam bending leads of the package is formed. A double forming area includes a first forming area forming the lead at one position of the respective lead and a second forming area, formed on an external side of the first forming area, supporting the formed lead. The first forming area corresponds to the second forming area in a gearing region of the lower and the upper dies, and each of the leads is contacted with the dies through the areas.

Description

Lead forming die with double forming area

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead forming die, and more particularly to a lead of a semiconductor chip package using an upper / lower mold having a double forming area of a primary / secondary bent portion. The present invention relates to a lead bending die of a lead bending device (Lead former) which reduces the friction between the upper and lower molds and the leads by bending and reducing the area where the upper and lower molds contact the leads of the semiconductor chip package.

The lead bending device is a semiconductor assembly device that bends the leads protruding out of the package body into arbitrary shapes in a lead frame-type semi-finished product in which the package body is molded with a molding resin such as epoxy molding compound (EMC).

Such a lead bending device basically includes a lead bending die composed of an upper / lower mold having a bent portion capable of bending the lead. The method of bending the lead using the upper / lower mold will be described in more detail. After each semiconductor chip package of the lead frame in which the package body is molded with the molding resin is placed on the lower mold, the upper mold is lowered, Leads may be bent along a shape, and may include one or more lead bending dies according to the bending method.

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an apparatus in which a lead is bent with a single lead bending die, and among them, a surface mount type such as a small out-line package (SOP). It will be described with reference to the device for bending the leads of the package).

1 is a cross-sectional view showing a bent portion of a conventional lead bending die. Referring to Figure 1 describes the process of bending the lead as follows.

After the semiconductor chip package (not shown) in which the leads protrude horizontally is placed on the seating surface 18 of the lower mold 10, the inner mold 20 of the upper mold 40 descends to fix the semiconductor chip package. As the inner mold 20 descends, the lead is bent while moving the cam 30 engaged with the inner mold 20. The bent part 32 of the upper mold 40 is formed at the end of the cam 30, and the lead is bent along the bent parts 32/12 and the contact surfaces 34/14 of the upper / lower mold.

Since the lead bending die is in contact with the entire portion of the lead through the bent portion and the contact surface, the contact friction with the lead is increased.

In addition, prior to bending the lead, the semiconductor chip package is generally electroplated with a tin (Sn) alloy containing some lead (Pb), which is commonly referred to as tin plating. The tin alloy to be plated may consist of about 85% tin and about 15% lead, and through this electroplating process, each lead is protected from external stress and, after final assembly, the substrate When mounted on the back), it can exhibit high mounting force.

However, the plated tin may peel off while these electroplated leads are bent in the conventional lead bending mold described above. That is, the tin plating layer of the relatively soft material may be peeled off by contact friction while contacting the upper / lower mold of the strong material, and the advantage of electroplating tin on each lead may be lost. .

In addition, it is a method of bending by applying a single pressure to the upper and lower mold bent portions, so that each lead is separated from the lead bending mold, and thus, a spring-back phenomenon in which the shape bent by elasticity is restored and deformed. Can be represented.

As described above, the peeling of the tin plating layer or the spring-back phenomenon of the lead may increase the defective rate of the lead bending process, and further, the reliability of the assembled semiconductor chip package may be degraded.

It is an object of the present invention to provide a lead bending mold including an upper / lower mold having a primary bent portion and a secondary bent portion formed thereon.

It is still another object of the present invention to provide a lead bending mold including an upper / lower mold in which a surface in contact with the lead is minimized.

1 is a cross-sectional view showing a bent portion of a conventional lead bending mold,

2 is a cross-sectional view briefly showing a lead bending mold according to an embodiment of the present invention;

3 is a cross-sectional view showing in detail the bent portion of FIG.

4A to 4E are cross-sectional views showing a state in which a lead is bent through a lead bending mold according to the present invention.

Description of the main parts of the drawing

10, 110: lower mold 12, 32: bent portion

14, 34: contact surface 18, 118: seating surface

20, 120: internal mold 30, 130: cam

40, 140: upper mold 112, 132: primary bent portion

116, 136: secondary bend portion 122: outer mold

170: upper body 172, 182: support

180: lower body 200: lead bending mold

210: semiconductor chip package 220: package body

230: lead 240: blade

In order to achieve this object, the present invention is a semiconductor device, the lower mold is placed; And an upper mold having a cam for bending the leads of the semiconductor package, the lead bending mold of the lead bending apparatus comprising: a primary bent portion for bending leads at one point of each lead; And a second bent part formed on an outer side of the first bent part and correcting the bent lead, wherein the two-stage bent part is formed to correspond to each other in the mating surface of the upper / lower mold, and each lead is formed as a primary / 2. Provided is a lead bending mold, characterized in that in contact with the upper / lower mold through the secondary bent.

In addition, the lead bending mold according to the present invention is characterized in that each lead is bent by the first bent portion and then each lead is corrected by the second bent portion.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

2 is a cross-sectional view schematically showing a lead bending die 200 according to an embodiment of the present invention, Figure 3 is a cross-sectional view showing in detail the bent portion of FIG. Referring to Figure 2 and 3 will be described the structure of the lead bending die 200 according to the present invention.

The lead bending mold 200 according to the embodiment of the present invention has a lower mold 110 in which a semiconductor chip package (not shown) is placed and an upper mold in which a cam 130 for bending leads of the semiconductor chip package is formed. 140). The upper mold 140 is also divided into the inner mold 120 and the outer mold 122 of the type that can move the cam 130, the inner mold 120 is the lower mold when the upper mold 140 is lowered ( The package body of the semiconductor chip package is fixed together with the mounting surface 118 of the 110.

The primary bent part 112 is formed at the inner side about the seating surface 118 of the lower mold 110 and the secondary bent part 116 is formed at the outside thereof, and the primary / Primary / secondary bends 132/136 are also formed at the ends of the cams 130 corresponding to the secondary bends 112/116. In addition, grooves are formed between the respective primary bent portions 132/112 and the secondary bent portions 136/116 of the upper and lower molds, and the recesses are formed during the lead bending process. Each lead and the upper and lower molds 140 and 110 do not contact each other.

As described above, the upper / lower molds 140/110 having the primary / secondary bends are connected to upper / lower bodies 170/180 to which upper / lower molds are inserted and fixed, and the upper body 170 is As the vertical mold 140 moves vertically, the upper mold 140 moves vertically to bend the lead of the semiconductor chip package. At this time, the support bodies 172 and 182 having a predetermined length are formed between the upper body 170 and the lower body 180 to prevent the upper body 170 from falling above a certain height.

4A to 4E illustrate a lead of the semiconductor chip package 210 through a lead bending mold having a two-stage bent portion-a primary bent portion 112 and 132 and a secondary bent portion 116 and 136-according to the present invention. It is sectional drawing which showed the process which 230 is bent sequentially. Referring to Figures 4a to 4e, the process of bending the lead in detail as follows.

The upper mold 140 is lowered after the package body 220 of the semiconductor chip package 210 is placed on the seating surface 118 of the lower mold 110 by a transfer means such as an index feeder (not shown). The inner mold 120 is fixed by pressing on the package body 220, while the upper mold is lowered, the cam 130 moves while drawing an arc P, the primary bent portion 132 is A of the lead 230 The point is pressed (Figure 4a).

As the primary bent portion 132 of the cam 130 moves further, the lead 230 is the B and C points by the primary bent portion 112 and the secondary bent portion 116 of the lower mold 110. Point A is bent in a concave shape (Fig. 4b), the cam 130 is moved further and the point A and the lower mold of the lead 230 pressed by the primary bent portion 132 of the cam 130 Between the C points of the lead 230 corresponding to the secondary bent portion 116 of 110 is bent in a loose state (Fig. 4C).

When the end of the cam 130 is finished, the secondary bent portion 136 of the cam 130 and the secondary bent portion 116 of the lower mold 110 return the lead 230 downward from the C point. By bending, the portion of the lid-between the B and C points of the lid-is corrected horizontally (FIG. 4D). In addition, the shape of the lead of the semiconductor chip package 210 is completed by cutting the lead with cutting means such as a blade 240 at the point D of the lead 230 which is later bent horizontally (FIG. 4E).

Leads bent according to such a process are prevented from peeling off the plated tin plated layer because the portion to be mounted when the substrate is finally mounted on the substrate-specifically, the section between B and D-does not directly contact the lead bending mold. can do.

In addition, even in the case of using a so-called PIF (PPF), which is plated with metals such as chromium (Cr) or manganese (Mn) in advance, the lead and bending molds may be used. Since the contact area is limited, damage such as cracking of PPF generated in the lead bending process can be reduced.

The structural feature of the lead bending die according to the present invention lies in the upper / lower mold in which the two-stage bent portion of the primary / secondary bending portion is formed. These primary and secondary bends bend the leads of the semiconductor chip package in an arbitrary form through a process in which the primary bends bend the leads downward and the secondary bends re-bending the leads horizontally to correct them.

In addition, compared to the conventional lead bending mold is bending by pressing the entire portion of the lead while bending once, the lead bending mold according to the present invention is a spring-back that is partially restored by bending the lead bending mold according to the present invention (Spring- back) can be prevented, and in addition, by contacting the lead at two points of the primary and secondary bends, the surface contact friction between the mold and the lead can be reduced, and as a result, the tin-plated layer on the surface of the lead is peeled off It can prevent losing phenomenon.

The structure of the lead bending mold including the upper / lower molds having the two-stage bending portions described above can be applied to not only the SOP described in the present invention but also to the QFP (Quad Flat Package) and the like. Obviously, it can be applied freely within the scope of the technical idea.

The lead bending mold according to the present invention includes upper and lower molds formed with primary and secondary bent portions to bend the leads formed to the outside of the semiconductor chip package into an arbitrary shape, and when the leads are bent through such a structure. Spring-back phenomenon or peeling off of the tin plating layer may be prevented. As such, by preventing the peeling of the tin plating layer, the mounting force may be improved when the semiconductor chip package is mounted on the substrate, and the yield of the lead bending process may be improved by preventing the spring-back phenomenon.

Claims (4)

A lower mold on which the semiconductor package is placed; And An upper mold having a cam for bending the leads of the semiconductor package; In the lead bending mold of the lead bending device comprising a, A primary bent part that bends the lead at one point of each lead; And A second bent part formed on an outer side of the first bent part and correcting the bent lead; A two-stage bending portion including a is formed to correspond to each other in the mating surface of the upper / lower mold, each lead is in contact with the upper / lower mold through the primary / secondary mold mold. The lead bending die according to claim 1, wherein the primary / secondary bending portion of the upper mold is formed at an end of the cam. 3. The lead bending die according to claim 2, wherein each lead is bent horizontally between the primary bent portion and the secondary bent portion. The lead bending die of claim 3, wherein the first and second bent parts correspond to both sides of a point where the leads are cut.