JPH10270618A - Lead frame, method of manufacturing lead frame, and semiconductor device - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a manufacturing method and structure capable of forming a wide lead width of a lead frame, and a semiconductor device using the same. SOLUTION: In a step of forming a lead frame by etching, each of the leads is formed by separately etching the front and back surfaces of a metal material 10 which is the base of the lead frame. After the front and back surfaces of the metal material 10 are separately etched, etching is performed again to form leads. [Effect] The inner lead 4 and the outer lead 7 can have a large flat width on one side or both sides of the front and back, and the occurrence of defects in the assembly process can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching lead frame for an integrated circuit on which an integrated circuit chip is mounted and a method for manufacturing the same.

[0002]

2. Description of the Related Art A conventional technique will be described below with reference to FIGS.

FIG. 5 is a plan view showing an example of a lead frame on which an integrated circuit chip is mounted. The frame 1 has a die pad 2 for mounting and fixing an integrated circuit chip substantially at the center. Further, the die pad 2 is supported on the frame 1 by tie bars 3. A large number of thin inner leads 4 extend from the inner wall of the frame 1 toward the die pad 2. Each inner lead 4 prevents the resin from flowing out when the resin is sealed in the molding area 5 in the molding process. It is supported by the dam bar 6 for. This dam bar 6
Is also a reinforcing member when wiring the integrated circuit chip mounted and fixed to the die pad 2 and the tip end of the inner lead 4 on the die pad side, and cuts the dam bar 6 between the leads after resin sealing. By cutting the dam bar 6, the outer leads 7 on the outer portion are separated from each other.

FIG. 6 is a sectional view showing a process in which the shape of the inner lead 4 or the outer lead 7 is formed.
A resist 11 is applied to both front and back surfaces of the metal material 10 of the etching lead frame that has been degreased. Subsequently, after exposing and developing to etch the metal material 10, the resist is peeled off, and the inner leads 4 and the outer leads 7 are removed.
Form the shape of. Of course, at this time, the shapes of the die pad 2, the tie bar 3, the dam bar 6, and the like are simultaneously formed. FIG. 6 shows the state after exposure and development. At this time, the etching is performed simultaneously from both the front and back surfaces of the metal material 10 so that the inner leads 4 and the outer leads 7 are formed.
Shape is formed.

[0005]

As described above, in the manufacturing process of the etching lead frame for semiconductor, as shown in FIG. 6, the etching is performed simultaneously from both the front and back surfaces of the metal material 10, so that the inner leads 4, the outer leads 7, and other parts are formed. The shape of the part is formed. The widths of the flat portions on the front surface and the back surface of the inner lead 4 and the outer lead 7 formed in this way are such that the metal material 1 is not only in the depth direction but also in the side direction.
Since the etching of 0 progresses, both the front and rear surfaces of the lead are considerably narrower than the width of the resist 11 shown in FIG. Numerically, the width of the resist is 1
When the thickness is 20 to 150 μm, the width of the completed lead is about 70 to 100 μm. In a multi-pin lead frame with a fine inner lead pitch, the width of the resist must be narrowed, and considering the side etching amount, the flat width of the lead required for wire bonding cannot be obtained.

In the semiconductor devices currently being manufactured, the inner leads are being miniaturized.

If the flat width of the inner lead 4 is smaller than the width required and necessary for wire bonding, when the integrated circuit chip and the tip of the inner lead 4 on the die pad side are press-bonded with the wire, the wire and the inner lead 4 are not bonded to each other. Defectives such as non-compression bonding and insufficient bonding strength occur frequently. That is, these defects are caused when the wire and the inner lead 4 are pressure-bonded.
If the width of the inner lead 4 is narrower than the diameter of the ball formed on the wire itself, and if the width of the back surface of the inner lead surface is narrow when the inner lead 4 is pressed by the wind clamper, the inner lead 4 becomes unstable and the lead rattles. It is due to being attached.

In the case of the outer leads 7 having a narrow flat width on the front and back, the outer leads 7 may be bent to the left or right in a forming step performed after resin sealing, or the height of each lead may be reduced in a surface mount type package. This causes defects such as unevenness.

Therefore, the flat widths of both the front and back surfaces or the front and back surfaces of the inner lead 4 and the outer lead 7 are shown in FIG.
It was strongly desired to provide a lead frame that can be formed to have a width equal to that of the resist 11 shown in FIG.

[0010]

SUMMARY OF THE INVENTION In an etching lead frame comprising a substantially rectangular die pad on which an integrated circuit chip is mounted and an inner lead having one end facing the die pad and having one end facing the die pad, metal materials are separated from each other. This is achieved by forming a lead shape by etching.

Further, it can be achieved by etching the metal material of the etching lead frame separately on the front and back sides and then performing another etching to form the shape of the lead.

[0012]

The flat material of the lead portion is formed by etching the front and back of the metal material 10 of the lead frame separately or by etching the front and back separately to form the shape of the lead. Can be equivalent to

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a first embodiment of the present invention, and is a schematic view of a manufacturing process of an etching lead frame in which the sections of the inner lead 4 or the outer lead 7 are listed in the order of manufacture.

FIG. 1A shows that a resist 11 is applied to both front and back surfaces of the metal material 10 which has been subjected to the degreasing treatment, followed by exposure and development.

Next, either one of the front and back surfaces is filled with an etching-resistant resin 12 or a different resist 12 from the already applied resist 11 is applied. At this time, the purpose of applying the resist 12 of a different type from the already applied resist 11 is to enable selective resist stripping.

After that, as shown in FIG. 3B, the metal material 10 on the surface opposite to the surface covered with the etching resistant resin or resist 12 is etched. At this time, the etching rate such as the etching time is changed and controlled so that the metal material 10, which is a conventional technique, does not progress in the depth direction as compared with the case where both surfaces are simultaneously etched.

By doing so, etching in the side direction can be suppressed more than in the case of forming by the conventional technique, and it becomes possible to form a lead having a wide flat width.

Then, as shown in FIG. 3C, the etching resistant resin or resist 12 is peeled off, and the opposite surface etched is filled with the etching resistant resin 12 or already applied. A resist 12 different in type from the existing resist 11 is applied. The metal material 10 on the surface opposite to the surface covered with the etching-resistant resin or the resist 12 is etched to complete the shape formation.

Finally, the above-mentioned resin or resist 12 having resistance to the etching solution and the resist 11 are peeled off, and the formation of the shape of the inner lead 4 or the outer lead 7 is completed.

In other words, by forming the leads as shown in FIG. 1, the etching of the metal material 10 in the depth direction becomes shallower on either side of the material than that formed by the conventional technique. Inevitably, the progress of the etching in the side direction can be suppressed on either one of the front and back sides of the material as compared with the case formed by the conventional technique. That is, the flat width of one side surface of the formed inner lead 4 or outer lead 7 can be made wider than that formed by the conventional technique.

FIG. 2 is a schematic view showing a manufacturing process of an etching lead frame according to a second embodiment of the present invention, in which sections of the inner lead 4 or the outer lead 7 are listed in the order of manufacture.

Up to the point where either the front surface or the back surface is filled with the etching resistant liquid resin 12 or a resist 12 of a different type from the resist 11 is applied and etching is performed, the first embodiment shown in FIG. The same is true.

Next, the etching resistant resin 12
Alternatively, the resist 12 is peeled off, and then the etched opposite surface is filled with an etching-resistant resin 12, or a different resist 12 from the already applied resist 11 is applied. The metal material 10 on the surface opposite to the surface covered with the etching-resistant resin or resist 12
Is etched. At this time, similarly to the etching of the opposite surface, control is performed so that the metal material 10 does not proceed in the depth direction as compared with the case where both surfaces of the metal material 10 of the related art are simultaneously etched.

Next, a resist 12 of a different type from the already applied resist 11 is applied to the entire surface of the metal material 10.

The entire inner lead 4 or outer lead 7 of the metal material 10 thus treated is exposed and developed, and the space is etched.

Finally, the two types of resists 11 and 12 are peeled off, and the formation of the shape of the inner lead 4 or the outer lead 7 is completed.

By doing so, the etching in the side direction on both the front and back surfaces can be suppressed as compared with that manufactured by the conventional technique, and it is possible to form leads having a wide flat width.

FIG. 3 is a third embodiment of the present invention, and is a schematic view of a manufacturing process of an etching lead frame in which the cross section of the inner lead 4 or the outer lead 7 is listed in the order of manufacture.

This is exactly the same as the second embodiment of the present invention shown in FIG. 2 and its manufacturing method, except that the width of the resist on one surface is increased.

FIG. 3 is a third embodiment of the present invention, and is a schematic view of a manufacturing process of an etching lead frame in which the cross section of the inner lead 4 or the outer lead 7 is listed in the order of manufacture.

This is also exactly the same as the second embodiment of the present invention shown in FIG. 2 and the manufacturing method thereof, but the width of the resist on both the front and back sides is widened.

By thus changing the width of the resist within the manufacturing process capability, it is possible to obtain a lead having a wider flat width as compared with the prior art and it is possible to selectively control the front and back widths and their balance. Becomes

The embodiments of the present invention have been described above. In this embodiment, the material and thickness of the resist and the etching resistant resin are not limited, but any material may be used as long as the embodiment of the present invention can be achieved. Further, the etching amount in the depth direction and the side direction of the material is not specified, but this may also be set in any manner as long as the embodiment of the present invention can be achieved.

[0035]

As described above, according to the present invention, the metal material of the etching lead frame is separately etched on the front and back, or after etching separately on the front and back, another one is obtained.
By performing the etching several times to form the shape of the lead, it becomes possible to make the flat width of one of the front and back surfaces of the inner lead and the outer lead, or the flat width of both the front and back surfaces, wider than that of the lead manufactured by the conventional technique. For this reason, insufficient bonding strength during wire bonding, lead skew failure in which the outer leads are bent to the left or right in the forming process performed after resin encapsulation, and the height of each lead in a surface mount type package Has an excellent effect of preventing coplanarity defects or the like from becoming non-uniform.

[Brief description of the drawings]

FIG. 1 is a lead formation process diagram (cross-sectional view) showing a first embodiment of the present invention.

FIG. 2 is a process diagram (cross-sectional view) of forming a lead showing a second embodiment of the present invention.

FIG. 3 is a process view (cross-sectional view) of forming a lead showing a third embodiment of the present invention.

FIG. 4 is a view (cross-sectional view) of a lead forming process showing a fourth embodiment of the present invention.

FIG. 5 is an overall view (plan view) of a lead frame.

FIG. 6 is a view (plan view) of a lead forming process showing a conventional method.

[Explanation of symbols]

 1 ... Frame frame 2 ... Die pad 3 ... Tie bar 4 ... Inner lead 5 ... Mold area 6 ... Dam bar 7 ... Outer lead 8 ... IC chip 9 ... Gold wire 10 ... Frame material 11 ... Resist 12 ... Etching liquid resistant resin / resist

Claims (6)

[Claims] 1. An etching lead frame comprising a substantially square die pad on which an integrated circuit chip is mounted and inner leads arranged on the periphery of the die pad and having one end directed toward the die pad, wherein a metal material is separately etched on the front and back sides. A lead frame characterized in that the shape of the lead frame is formed. 2. An etching lead frame comprising a substantially square die pad on which an integrated circuit chip is mounted and inner leads arranged on the periphery of the die pad and having one end facing the die pad, after the metal material is separately etched on the front and back sides. A lead frame characterized in that the shape of the lead is formed by performing another etching. 3. The method of manufacturing a lead frame according to claim 1, wherein the lead shape is formed by separately etching a metal material on the front and back sides. 4. The method of manufacturing a lead frame according to claim 1, wherein the metal material is separately etched on the front and back sides, and then the shape of the lead is formed by performing another etching. 5. A semiconductor device using a lead frame according to claim 1, wherein the metal material is separately etched to form leads. 6. The semiconductor device using a lead frame according to claim 2, wherein the lead material is formed by etching the metal material separately for the front and back surfaces and then performing another etching.