JPH10144841A - Method for forming lead and apparatus for correcting shape of lead - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time required for adjusting a die significantly by pressing the shoulder part of a gull-wing lead while holding the lower surface at the forward end part thereof on a horizontal plane thereby forming the lead correctly. SOLUTION: A unit semiconductor device 12 where the leads are not yet formed is set in a lead former and formed into a gull-wing shape. The leads 13 of the semiconductor device 12 is formed into a gull-wing shape having first and second bends 13b, 13d. When a punch 2 is lowered for a predetermined stroke in the direction shown by an arrow D, the pressing part 2a of the punch 2 presses the lead 13 of the semiconductor device 12 at the shoulder part 13b thereof to push down the semiconductor device 12 entirely in the direction of the die 4. Since the holding face 4b of the die 4 is horizontal, forward end of the lead 13 is moved to separate from a stopper part 4a and the first and second bends 13c, 13d are made correspondingly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead forming method and a lead shape correcting device suitable for forming a lead into a gull wing shape in a semiconductor device having a gull wing shape. .

[0002]

2. Description of the Related Art Normally, a semiconductor device that has undergone a molding resin encapsulation process is sent to a T / F (trim and form) process, where lead forming of the semiconductor device is performed. As a lead shape of a surface mount device, for example, there is a gull wing shape having two bent portions. In order to form the lead into a gull wing shape, the lead is bent using a die including a punch and a die. The shape of the lead formed by the bending process described above requires that the values of the lead tip angle, coplanarity, stand-off, etc. be within the standard values, and that each of these values must be It has been requested that the device be as small as possible. Here, the lead tip angle refers to the maximum value of the inclination angle of the lead tip with respect to the lower surface of the package, and the coplanarity refers to the distance of the lead from the plane when the package is placed on a plane. And the stand-off refers to the maximum value of the distance between the lower surface of the package and the lead end surface.

[0003]

Conventionally, various standards required for the shape of the lead of the semiconductor device described above have been adjusted by adjusting the shape of the molding die or the amount of movement stroke. Values were achieved, and variations in lead shape were suppressed. However, there is a problem that it takes a long time to adjust the mold to achieve the respective standard values and suppress the above-mentioned variation in the shape of the lead, and the man-hour is large. Further, although the shape of the lead can be adjusted to be within the above-mentioned respective standard values by performing the adjustment, it is difficult to sufficiently suppress the variation in the lead shape.

The present invention has been made in view of such a conventional problem, and it is possible to greatly reduce the variation in the shape of the lead of a semiconductor device in which the lead has a gull-wing shape. It is an object of the present invention to provide a lead molding method and a lead shape correcting device capable of greatly reducing the time required for adjusting a mold for suppressing variations in lead shape.

[0005]

SUMMARY OF THE INVENTION A lead forming method according to the present invention is a forming method for forming a lead of a semiconductor device into a predetermined gull wing shape, wherein the lead of the semiconductor device is formed into a gull wing shape. And a correcting step of pressing the shoulder opening of the lead while holding the lower surface of the tip end of the gull-winged lead in a horizontal plane to form the lead into an appropriate shape.

In the lead forming method according to the present invention, the lead is formed into a gull-wing shape in a forming step, and the shoulder opening of the lead is held in a correcting step while holding the lower surface of the tip of the gull-wing shape in a horizontal plane. By pressing, the respective values of the lead tip angle, coplanarity, and standoff are simultaneously improved, and variations in the lead shape are suppressed.

A lead shape correcting apparatus according to the present invention comprises a die for holding a semiconductor device having leads formed in a gull wing shape, and a punch for pressing a lead of the semiconductor device held on the die in the direction of the die. The die has a flat surface that is horizontal with respect to the lower surface of the package of the semiconductor device, and a holding portion that holds the lower surface of the tip of the lead is formed. The punch has a shoulder opening portion of the lead. Is formed.

In the lead shape correcting device according to the present invention, the semiconductor device formed into a substantially predetermined gull wing shape is formed by punching the shoulder opening of the lead while the lower surface of the tip of the lead is held by the holding portion of the die. And the values of the lead tip angle, coplanarity, and standoff are simultaneously improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a lead forming method and a lead shape correcting device according to the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing one embodiment of a punch and a die in the lead shape correcting device according to the present invention. Before describing the lead shape correcting device according to the present invention, an outline of equipment in a T / F process of a semiconductor device to which the lead shape correcting device according to the present invention is applied is shown in FIG.

[0010] In FIG. 4, a semiconductor device group 11 in which a plurality of semiconductor devices are connected via a lead frame is moved to a transfer section 22 by a transfer device (not shown), and sent to a die removing device 23. In the removal device 23, the semiconductor device group 1
1 of the lead frame is cut, and the single semiconductor device 12 is cut.
Becomes The semiconductor device 12 is sent to a lead forming device 14 where the leads of the semiconductor device 12 are formed into a gull-wing shape. The semiconductor device 12 in which the leads are formed
The lead is sent to the lead shape correcting device 16 and the lead shape is corrected to an appropriate shape. The semiconductor device 12 whose lead shape has been modified is stored in the storage section 18.

The above lead forming apparatus 14 is shown in FIG.
As shown in the figure, the driving unit 14a, the upper mold 14b, the lower mold 1
4d and a holding table 14c. The upper mold 14b is driven by the drive unit 14a and is movable with respect to the lower mold 14d held on the holding table 14c. The semiconductor device 12 is set at a predetermined position of the lower mold 14d, and the upper mold 14b is lowered, so that the leads 13 of the semiconductor device 12
Is pressed by the upper mold 14b and the lower mold 14d to obtain a gull-wing-shaped lead shape as shown in FIG.

On the other hand, the lead shape correcting device 16 is shown in FIG.
Punch 2 driven by drive section 16a shown in (b)
And the die 4 held on the holding table 16b, and the punch 2 descends to correct the shape of the lead 13 of the semiconductor device 12 held on the die 4. Here, FIG. 1 shows the structure within the circle A in FIG. In FIG. 1, the punch 2 is moved by an arrow B1 by the driving unit 16a.
And B2 direction. This punch 2
A pressing portion 2a for pressing the shoulder opening of the lead 13 formed into a gull-wing shape of the semiconductor device 12 is formed on the front end of the semiconductor device 12 so as to correspond to the leads 13 formed on the four side surfaces of the semiconductor device 12.

At the tip of the die 4 provided opposite to the punch 2, the movement of the punch 2 descending with respect to the die 4 is regulated and the semiconductor device 1 held on the die 4 is held.
A convex stopper portion 4a for preventing the 2 from moving on the die 4 is formed on all sides. The lead 1 formed in a gull wing shape is formed around the stopper 4a.
3 is a holding surface 4b for holding the semiconductor device 12 by holding the lower surface of the tip portion. Above stopper part 4
The space surrounded by a is a housing portion 4c in which a package of the semiconductor device 12 in which the tip of the lead 13 is held by the holding surface 4b is housed with a gap.

Next, an embodiment of the lead forming method according to the present invention using the lead forming device 14 and the lead shape correcting device 16 configured as described above will be described. First, the single semiconductor device 12 in which the above-mentioned lead is not formed is set in the lead forming device 14 and the lead is formed into a gull-wing shape. As shown in FIG. 3, the lead 13 of the semiconductor device 12 has a first bent portion 13b and a second bent portion 13b.
Is formed into a gull-wing shape having a bent portion 13d.

At this time, the lead 13 is formed so that the coplanarity Cp, the standoff Sf, and the lead tip angle θ of the lead 13 fall within the standard values. Coplanarity Cp is
This is the maximum value of the distance between each of the leads floating above the horizontal plane P and the horizontal plane P, such as the lead 13 'indicated by a dotted line in FIG. The lead tip angle θ is the maximum value of the inclination angles of each lead tip with respect to the lower surface 12a of the package of the semiconductor device 12. The standoff Sf is the maximum value of the distance between the package lower surface 12a and the tip surface of each lead 13.

Coplanarity Cp, standoff Sf,
As a standard value of the lead tip angle θ, for example, the coplanarity Cp is 40 μm at the maximum and the standoff Sf is 10
0 ± 50 μm, and the lead tip angle θ is 3 ° ± 3 °.
Therefore, coplanarity Cp, standoff Sf,
Since the lead tip angle θ only needs to be within a certain range, the lead forming device 14 can relatively easily form the lead 13. Further, in the forming process by the lead forming device 14, the coplanarity Cp, the standoff Sf, and the lead tip angle θ need only be within the respective standard values.
f, there is no need to suppress variations in the value of the lead tip angle θ, and there is almost no need to perform fine adjustment and maintenance on the upper and lower dies 14b and 14d.

Next, the gull-wing shaped semiconductor device 12 obtained in the forming step by the lead forming device 14 is set in the lead shape correcting device 16 and the leads 13 of the semiconductor device 12 are corrected to an appropriate shape. Each lead 13 of the semiconductor device 12 is connected to the above-mentioned coplanarity Cp, stand-off Sf,
Since fine adjustment for suppressing the variation of each value of the lead tip angle θ is not performed, there is a variation in each value. Therefore, this variation is corrected in the correction process by the lead shape correction device 16.

The semiconductor device 1 formed in the gull wing shape obtained in the forming process by the lead forming device 14
2 is set on the die 4 of the lead forming device 14,
As shown in FIG. 2, the lower surface 13 a of the tip of the lead 13 is held by the holding surface 4 b of the die 4. The package of the semiconductor device 12 is housed in the housing portion 4c with a gap, and a gap exists between the shoulder opening 13b of the lead 13 and the tip of the stopper 4a of the die 4.

In this state, when the punch 2 is lowered in the direction of arrow D by a predetermined moving stroke, the pressing portion 2a of the punch 2 presses the shoulder opening 13b of the lead 13 of the semiconductor device 12, and the entire semiconductor device 12 Is pushed down in the die 4 direction. Accordingly, since the holding surface 4b of the die 4 is a horizontal surface, the tip of the lead 13 moves in a direction away from the stopper portion 4a, and the first and second bent portions 13c and 13d are adjusted accordingly. Deform. As a result, the lead 13 is deformed and corrected as a whole in the direction of the arrow E, and the coplanarity Cp, the standoff Sf, and the variation in the lead tip angle θ are corrected simultaneously. The moving stroke amount of the punch 2 is adjusted in advance to an optimum amount so that the coplanarity Cp, the standoff Sf, and the lead tip angle θ of the lead 13 do not become out of the standard values. Further, even if the punch 2 moves down by a predetermined moving stroke, the pressing portion 2 a of the punch 2 does not come into contact with the tip of the stopper 4 a of the die 4 via the lead 13. The stopper 4a of the die 4 is used to stop the punch 2 if the punch 2 drops for a certain reason beyond a predetermined moving stroke.
This is because it is provided in order to restrict the movement of the object.

As described above, according to the lead forming method of the present embodiment, the coplanarity C
It is possible to form the semiconductor device 12 in which variations in p, standoff Sf, and lead tip angle θ are simultaneously improved. Further, since the process is divided into a molding process and a correction process, fine adjustment for suppressing variations in coplanarity Cp, standoff Sf, and lead tip angle θ of the lead 13 during molding is not required, and the man-hour required for the adjustment is greatly reduced. Can be reduced.

According to the lead shape correcting apparatus according to the present embodiment, it is only necessary to move the punch 2 on which the pressing portion 2a is formed with respect to the lead 13 of the semiconductor device 12 held by the die 4 by a predetermined amount and press it. The variation in the coplanarity Cp, the standoff Sf, and the lead tip angle θ are simultaneously improved, and the semiconductor device 12 in which the shape of the lead 13 is within the standard value can be manufactured. Further, the lead 13 of the semiconductor device 12 does not come into contact with the upper surface of the tip of the lead 13.
No indentation is formed on the upper surface of the tip of the. For this reason, no problem occurs when the lead shape inspection performed in a later step is performed by the image processing apparatus.

[0022]

As described above, according to the lead forming method of the present invention, the coplanarity, standoff, and lead angle of the lead shape of the semiconductor device can be kept within the standard values. These values can be corrected to suppress variations. Further, since the lead forming method according to the present invention is divided into a forming step and a correcting step, fine adjustment for keeping within a standard value in the forming step is not required, and the man-hour required for the adjustment can be greatly reduced. In addition, the variation can be easily suppressed in the repairing process, and a large number of steps can be reduced as a whole.

In the lead shape correcting device according to the present invention, the punch is moved by a predetermined amount to the die and pressed.
Since the values of the coplanarity, standoff, and lead angle of the lead of the semiconductor device can be corrected, the structure is very simple, and fine adjustment and maintenance of the die and punch are very easy.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a punch and a die in a lead shape correcting device according to the present invention.

FIG. 2 is an explanatory view showing a state in which the shape of the lead of the semiconductor device is corrected by the punch and the die shown in FIG. 1;

FIG. 3 shows coplanarity, standoff,
It is explanatory drawing which shows a lead tip angle.

FIG. 4 is an explanatory diagram showing an example of an outline of equipment in a T / F process.

FIG. 5 (a) is an explanatory diagram showing an example of a configuration of a lead forming device, and FIG. 5 (b) is an explanatory diagram showing an example of a configuration of a lead shape correcting device according to the present invention.

[Explanation of symbols]

Reference numeral 2 indicates a punch, 2a indicates a pressing portion, 4 indicates a die, 4a indicates a stopper portion, 4b indicates a holding surface, 4c indicates a housing portion, and 12 indicates a semiconductor device.
13 ... Lead.

Claims (2)

[Claims] 1. A molding method for molding a lead of a semiconductor device into a predetermined gull wing shape, comprising: a molding step of molding a lead of the semiconductor device into a gull wing shape; Pressing the shoulder opening of the lead while holding the lower surface in a horizontal plane to form the lead into an appropriate shape. 2. A die for holding a semiconductor device having leads formed in a gull-wing shape, and a punch for pressing a lead of the semiconductor device held by the die toward the die direction, wherein the die has A holding portion for holding a lower surface of a tip portion of the lead is formed, and a pressing portion for pressing a shoulder opening of the lead is formed on the punch. Lead shape correction device.