JPH08125089A - Lead frame and semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE: To eliminate the step of cutting a dam bar by providing the bar of solder material in the shape of filling the gap between a plurality of leads at a boundary between the outer lead and the inner lead of the leads. CONSTITUTION: A tab 2 for mounting a chip with a semiconductor element is provided at the center. The tab 1 is connected to a frame 4 by tab hanging leads 3 of four directions at the corners of a rectangle. A plurality of leads 5 are arranged toward the interior of the frame 4. A dam bar 6 as a solder material is provided in the shape of filling the gap between the leads 5 at the boundary between the outer lead 5a and the inner lead 5b of the leads 5. Thus, the flow-out of the resin at the step of resin sealing can be stopped by the bar 6. Since the bar 6 can be melt and removed, the step of cutting the bar 6 can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame, a semiconductor device using the same, and a manufacturing technique thereof.
In particular, the present invention relates to a lead frame in which the manufacturing process is simplified by omitting a die for cutting a dam bar in the lead frame and a technique effectively applied to a semiconductor device using the same.

[0002]

2. Description of the Related Art A semiconductor device such as a semiconductor integrated circuit device, for example, tends to have a large number of pins and a fine pitch as it is miniaturized, highly integrated, and multifunctional. Examples of package technologies that support these are QFP (Quad Flat Pa
A resin-sealed package called ckage) is used.

A chip in which a semiconductor element such as a semiconductor integrated circuit is formed is mounted on a dam at the center of a lead frame of a semiconductor device of this type. Then, the connection electrode on the surface of the chip and the inner lead of the lead frame are wire-bonded by a bonding wire,
It is sealed with a resin sealing body. The outer lead of the lead frame is processed into a gull wing shape.

As a document describing a lead frame for resin encapsulation, for example, JP-A-55-2 is used.
There is one described in Japanese Patent No. 1128.

[0005]

However, with the increase in the number of pins and the fine pitch of semiconductor devices, for example, a package having 300 or more outer leads and a pitch of 0.3 mm or less has been developed. There is a problem that the cutting process of the dam bar of the frame becomes very difficult.

Therefore, a lead frame having a dambarless structure has been studied. However, with respect to the lead frame having the dambar-less structure, there arises a problem that the resin for sealing cannot be prevented from flowing out in the resin sealing step, and the leadframe with the dambar is still used in practice.

An object of the present invention is to provide a lead frame which does not require a dam bar cutting process.

Another object of the present invention is to provide a semiconductor device using a lead frame which does not require a dam bar cutting step.

Still another object of the present invention is to provide a method of manufacturing a semiconductor device using a lead frame which can simplify the manufacturing process of the semiconductor device.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0011]

The typical ones of the inventions disclosed in the present invention will be outlined below.

(1) It is assumed that the lead frame of the present invention has a shape in which a dam bar made of solder is embedded between a plurality of leads at the boundary between the outer lead and the inner lead in the lead.

(2) The method of manufacturing a semiconductor device according to the present invention
A step of mounting a chip with a semiconductor element formed on a tab in a lead frame having a dam bar made of solder, and fixing the chip to the tab, and using a wire bonding device, connecting electrodes and leads on the surface of the chip The step of connecting the inner leads of the frame with the bonding wires, and using the resin sealing device, set the lead frame in the molding die and press the sealing resin into the cavity of the molding die. A resin encapsulant is formed and at least the chip and the inner lead are packaged, and the dam bar is heated to melt the solder that is the material of the dam bar and remove the dam bar from the lead in the lead frame. .

[0014]

[Action]

(1) According to the lead frame of the present invention described above, since the dam bar made of solder is embedded between the plurality of leads at the boundary between the outer lead and the inner lead in the lead,
The dam bar can prevent the resin from flowing out in the resin sealing process.

Further, according to the lead frame of the present invention described above, since the dam bar is made of solder, the dam bar can be removed after the resin sealing process, for example, in the lead frame plating process. Since the dam bar made of solder can be melted and removed by the heat treatment, the dam bar cutting process can be eliminated and the dam bar can be removed by a simple process without using a cutting die. .

(2) According to the method for manufacturing a semiconductor device of the present invention described above, the resin sealing step is performed by using the lead frame having the dam bar made of solder, so that the dam bar can be used in the resin sealing step. The outflow of resin can be stopped.

Further, since the dam bar is made of solder, the dam bar can be removed by heating after the resin sealing step, for example, heat treatment such as lead plating in the lead frame. The dam bar can be removed by a simple process without using a cutting die.

As a result, the step of removing the dam bar is a simple step, and the manufacturing step of the semiconductor device such as the lead plating process in the lead frame can be diverted. Since manufacturing time can be shortened and manufacturing equipment such as a cutting die for the dam bar can be eliminated, throughput can be improved and cost can be reduced.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for explaining the embodiments, those having the same function are designated by the same reference numerals, and a duplicate description will be omitted.

(Embodiment 1) FIG. 1 is a plan view showing a lead frame which is an embodiment of the present invention. FIG. 2 shows FIG.
It is sectional drawing which shows the AA arrow cross section in. The lead frame of the present invention will be described with reference to FIG.

The lead frame 1 of this embodiment has a tab 2 in the center thereof, on which a chip on which a semiconductor element such as a semiconductor integrated circuit is formed is mounted. The tab 2 is connected and held to the frame 4 by tab suspension leads 3 in four directions at the corners of the four sides. In addition, 4a and 4b shown in FIG. 1 indicate holes used for alignment of the lead frame 1 and the like.

A plurality of leads 5 are arranged toward the inside of the frame 4. The lead 5 includes an outer lead 5a and an inner lead 5b.

The outer lead 5a of the lead 5 is also used.
A dam bar 6 made of solder is adhered to the boundary between the inner lead 5b and the inner lead 5b. The dam bar 6 made of solder is provided so as to be embedded between the plurality of leads 5 and is provided around the dam bar 6. Further, the thickness of the dam bar 6 is equal to or larger than the thickness of the lead 5.

The dam bar 6 made of solder having such a shape is circumferentially provided so that the sealing resin does not leak from the resin sealing line during resin sealing.
The dam bar 6 can prevent the sealing resin from flowing out in the resin sealing process.

The dam bar 6 is made of solder that does not melt in the pellet bonding process, wire bonding process and resin sealing process. As one mode of the dam bar 6 in the lead frame 1 of the present embodiment, solder having a melting point (melting temperature) of 270 ° C. or higher is used. As a result, the temperature in the pellet bonding process is about 180 ° C., the temperature in the wire bonding process is about 250 ° C., and the temperature in the resin sealing process is 18 ° C.
In the manufacturing process of one aspect of the semiconductor device having a temperature of about 0 ° C., the dam bar 6 is not melted by these processes, and sufficiently functions as the dam bar 6 in the resin sealing process.

The solder as the material of the dam bar 6 is, for example, an alloy of lead (Pb) and tin (Sn), and the solder having a desired melting point is prepared by changing the composition ratio, that is, the component ratio of lead and tin. can do. Lead is used to lower the melting point and increase the strength, and tin mainly plays a role of adhesion because it is easy to form an alloy with iron or copper.

The solder as the material of the dam bar 6 has a melting point of 240 ° C. when the component ratio of lead and tin in weight% of 4: 6, and a melting point of 300 ° C. when it is 1: 9.

Therefore, the solder as the material of the dam bar 6 has a melting point of 240 ° C. to 300 ° C., for example, by adjusting the component ratio of lead and tin in the weight% of 4 to 6 to 1: 9. It is possible to obtain a solder having a desired melting point up to ° C.

As another embodiment of the solder as the material of the dam bar 6, an alloy of lead, tin, and silver can be applied, and the weight ratio of these components is 93.5: 5: 5.
When it is set to 1.5, the melting point becomes about 300 ° C. Further, as the solder for the material of the dam bar 6, for example, solder such as an alloy of lead and silver or an alloy of bismuth and tin can be used.

The lead frame 1 of this embodiment is manufactured by forming the pattern of the lead frame 1 on a metal plate made of a metal such as 42 alloy which is an alloy of iron and nickel or copper, for example, by pressing. Although the lead frame 1 shown in FIG. 1 shows one pattern, it may be in the form of a lead frame in which two or more patterns are connected.

Next, the outer lead 5a in the lead 5
After a band-shaped and square-shaped solder corresponding to the shape of the dam bar 6 is placed on the boundary between the inner lead 5b and the inner lead 5b, the solder is embedded between the plurality of leads 5 by, for example, pressing.

Next, the solder remaining on the surface of the lead 5 is scraped off to remove the dam bar 6 as shown in FIG.
To form a lead frame 1.

The operation of embedding the dam bar 6 made of solder in the lead frame 1 between the plurality of leads 5 can be performed by pressing the molding die in the resin sealing device in the resin sealing step. In this case, the strip-shaped and square-shaped solder as the dam bar 6 may be placed on the lead frame 1 immediately before the resin sealing step.

The lead frame 1 of this embodiment is composed of the leads 5
Since the dam bar 6 made of solder is embedded between the plurality of leads 5 at the boundary between the outer lead 5a and the inner lead 5b in FIG. The outflow of resin can be stopped.

Since the lead frame 1 of this embodiment is made of solder as the dam bar 6, the dam bar 6 is also removed after the resin sealing step, for example, the lead 5 plating step in the lead frame 1. Since the dam bar 6 made of solder can be melted and removed by a heat treatment such as the above, the step of cutting the dam bar 6 can be eliminated and the dam bar 6 can be easily cut without using a cutting die. Can be removed by.

As a result, the step of removing the dam bar 6 is a simple step and, for example, the lead frame 1 is removed.
Since it is possible to divert the semiconductor device manufacturing process such as the lead 5 plating process in FIG. 1 to shorten the manufacturing time in manufacturing the semiconductor device and to eliminate the need for manufacturing equipment such as a cutting die for the dam bar 6. Therefore, the throughput can be improved and the cost can be reduced.

Further, in the lead frame 1 of this embodiment, since the dam bar 6 can be melted and removed, the step of cutting the dam bar 6 can be eliminated and the dam bar 6 can be cut by using a die. Since the number of leads 5 can be increased and the pitch of the leads 5 can be reduced by microfabrication, it can be removed by a simple process. For example, the number of leads 5 is 300 or more and the pitch between the leads 5 is 0.3 mm or less. It is possible to form a lead frame in which a large number of fine leads 5 are arranged with a fine pitch.

Further, the semiconductor device using the lead frame 1 of the present embodiment uses the lead frame 1 in which a large number of fine leads 5 are arranged at a fine pitch, and the dam bar 6 is removed by heating. It suffices to perform the treatment, and the step of cutting the dam bar 6 can be eliminated, and the dam bar 6 can be removed by a simple step without using a cutting die, so that the manufacturing step can be simplified. .

Further, the semiconductor device using the lead frame 1 of this embodiment can be miniaturized, highly integrated and multifunctional, and can be a semiconductor device having a large number of pins and a fine pitch.

(Embodiment 2) FIGS. 3 to 6 are plan views showing a manufacturing process of a semiconductor device using a lead frame which is another embodiment of the present invention. A method of manufacturing a semiconductor device using the lead frame of the present invention will be described with reference to FIG.

First, as shown in FIG. 3, the lead frame 1 of the first embodiment described above is prepared, and the tab 7 is mounted with the chip 7 on which a semiconductor element such as a semiconductor integrated circuit is formed, and pellets are formed. Bonding is performed to fix the chip 7 to the tab 2.

Next, as shown in FIG. 4, a connection electrode (not shown) on the surface of the chip 7 and the inner lead 5 of the lead frame 1 are used by using a wire bonding device.
b is connected by a bonding wire 8 such as a gold wire.

Next, as shown in FIG. 5, using a resin sealing device, the lead frame 1 after the wire bonding process is set in a molding die and, for example, a thermosetting resin or the like is used for sealing. The resin is pressed into a cavity of a heated molding die to form a resin sealing body 9, and the inner lead 5b, the chip 7, the bonding wire 8 and the like in the lead frame 1 shown in FIG. 4 are packaged.

In this case, the dam bar 6 functions as a mold resin stopping dam portion of the resin-sealed semiconductor device, and surrounds the lead 5 in order to prevent the sealing resin from flowing out in the resin sealing process. It has been set up. Also, dam bar 6
Is mechanically reinforced between the leads 5,
It has a function of preventing the lead 5 from being deformed and displaced.

Therefore, for example, when the lead 5 is mechanically stable and mechanical reinforcement is unnecessary, the dam bar 6 may be provided only in the resin sealing step,
It is possible to adopt a mode in which it is not necessary to previously provide the dam bar 6 on the lead frame 1 before the pellet bonding step described above corresponding to another specification of the manufacturing process of the semiconductor device.

In the manufacturing process of this type of semiconductor device, a pellet is formed by using a lead frame in which the dam bar 6 made of solder is set but not embedded between the leads 5 or a lead frame not provided with the dam bar 6. After performing the bonding process and the wire bonding process, the outer lead 5a in the lead frame
The solder as the material of the dam bar 6 may be provided between the plurality of leads 5 at the boundary between the inner lead 5b and the inner lead 5b. Further, the dam bar 6 may be made of the above-mentioned solder that does not melt in the pellet bonding process, the wire bonding process and the resin sealing process, but at least the solder that does not melt in the resin sealing process is used. You can also

After that, a lead frame was set in a molding die using a resin sealing device, and solder as a material of the dam bar 6 was pressed by the molding die to be embedded between a plurality of leads 5. After shaping, the resin for sealing is press-fitted into the cavity of the molding die to form the resin sealing body 9, and the inner lead 5b, the chip 7, the bonding wire 8 and the like in the lead frame may be packaged. .

As described above, in the present embodiment, the dam bar 6 made of solder is embedded between the plurality of leads 5 at the boundary between the outer lead 5a and the inner lead 5b in the lead 5. Thus, the dam bar 6 can prevent the resin from flowing out in the resin sealing step. That is, dam bar 6
Since it is provided around the lead 5, it functions as a mold resin stopping dam portion of the resin-encapsulated semiconductor device, can prevent the resin for encapsulation from flowing out in the resin encapsulation step, and can encapsulate the resin. The resin for sealing does not leak from the line.

Next, as shown in FIG. 6, the dam bar 6 made of solder is heated at a temperature higher than the melting point of the solder to melt the dam bar 6, and the dam bar 6 is fixed to the lead frame 1.
Work to remove from. In this case, the solder that is the material of the dam bar 6 may be completely removed from the lead frame 1, or a slight amount of solder may remain in the leads 5 of the lead frame 1. The reason is that the lead 5 in the lead frame 1 in the subsequent process is
Alternatively, a small amount of solder remains in the step of plating the lead 4 after removing the frame 4 because the plating can be performed more favorably.

The heat treatment in this step can be carried out using a local and short-time heat treatment apparatus such as high-frequency heating, and can be carried out in a short time and with a simple operation. Further, this step can be performed by melting the solder as the dam bar 6 in the plating process of the lead 5 of the lead frame 1.

As a result, the dam bar 6 can be removed by a simple process without using a cutting die. Further, the step of removing the dam bar 6 is a simple step, and the manufacturing step of the semiconductor device such as the plating processing step of the lead 5 in the lead frame 1 can be diverted to perform the manufacturing step of the semiconductor device. Since the time can be shortened and manufacturing equipment such as a cutting die for the dam bar 6 can be dispensed with, throughput can be improved and cost can be reduced.

(Embodiment 3) FIG. 7 is a plan view showing a lead frame which is another embodiment of the present invention. FIG. 8 is an enlarged cross-sectional view showing a cross section taken along the line BB in FIG. 7.

The lead frame 10 of the present embodiment is of a mode in which the number of leads 5 is increased in accordance with the increase in the number of pins and the fine pitch of the semiconductor device.

In the lead frame 10 of this embodiment, the dam bar 6 can be melted and removed, so that the step of cutting the dam bar 6 can be eliminated and the dam bar 6 can be simply cut without using a die. Since it is possible to increase the number of leads 5 and to reduce the pitch of the leads 5 by fine processing, it is possible to obtain a lead frame in which a large number of fine leads 5 are arranged with a fine pitch. .

Further, the semiconductor device using the lead frame 10 of this embodiment uses the lead frame 1 in which a large number of fine leads 5 are arranged at a fine pitch, and heating for removing the dam bar 6 is performed. Just do the processing,
Since the step of cutting the dam bar 6 can be eliminated and the dam bar 6 can be removed by a simple process without using a cutting die, the manufacturing process thereof can be simplified.

Further, the semiconductor device using the lead frame 10 of this embodiment can be miniaturized, highly integrated and multifunctional, and can be a semiconductor device having a large number of pins and a fine pitch.

The lead frame 10 of this embodiment has a different pattern from the lead frame 1 of the first embodiment described above, but since it is a functionally similar lead frame, a detailed description thereof will be omitted.

The invention made by the present inventor has been specifically described above based on the embodiments. However, the present invention is not limited to the above embodiments 1, 2, and 3 and is within a range not departing from the gist thereof. It goes without saying that various changes can be made.

For example, the pattern of the lead frame, the number of leads, the shape of the dam bar made of solder, the composition of the solder, and the like can be set in various modes as necessary.

Further, the pattern of the lead frame and the shape of the dam bar made of solder can be made into various modes so that it can be applied to various semiconductor integrated circuit devices using the lead frame and the manufacturing method thereof.

[0061]

The effects obtained by the typical ones of the inventions disclosed in this application will be briefly described as follows.
It is as follows.

(1) According to the lead frame of the present invention,
Since the dam bar made of solder is embedded between the plurality of leads at the boundary between the outer lead and the inner lead in the lead, the dam bar can prevent the resin from flowing out in the resin sealing step. it can.

According to the lead frame of the present invention,
Since the dam bar is made of solder, the dam bar can be removed by melting the dam bar made of solder by a heat treatment such as a step after the resin sealing step, for example, a lead plating step in the lead frame. Therefore, the step of cutting the dam bar can be eliminated, and the dam bar can be removed by a simple step without using a cutting die.

Further, according to the lead frame of the present invention, since the dam bar can be melted and removed,
Since the dam bar cutting process can be eliminated and the dam bar can be removed by a simple process without using a cutting die, the number of leads can be increased by fine processing and the lead pitch can be reduced, It is possible to obtain a lead frame in which a large number of fine leads are arranged with a fine pitch.

(2) According to the semiconductor device using the lead frame of the present invention, a lead frame in which a large number of fine leads are arranged at a fine pitch is used, and a heat treatment is performed to remove the dam bar. The dam bar cutting process can be omitted, and the dam bar can be removed by a simple process without using a cutting die, so that the manufacturing process can be simplified.

Further, according to the semiconductor device using the lead frame of the present invention, the semiconductor device can be miniaturized, highly integrated, and have multiple functions, and can have a multi-pin structure and a fine pitch.

(3) According to the method of manufacturing a semiconductor device of the present invention, the resin sealing step is performed by using the lead frame having the dam bar made of solder, so that the resin in the resin sealing step is damped by the dam bar. The outflow can be stopped.

Further, since the dam bar is made of solder, the dam bar is also removed by a heat treatment such as a step after the resin sealing step, for example, a lead plating step in the lead frame and the like. The dam bar can be removed by a simple process without using a cutting die.

As a result, the step of removing the dam bar is a simple step, and the manufacturing step of the semiconductor device such as the lead plating process in the lead frame can be diverted. Since manufacturing time can be shortened and manufacturing equipment such as a cutting die for the dam bar can be eliminated, throughput can be improved and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view showing a lead frame which is an embodiment of the present invention.

FIG. 2 A- of a lead frame which is an embodiment of the present invention
It is sectional drawing which shows the A arrow cross section.

FIG. 3 is a plan view showing a manufacturing process of a semiconductor device using a lead frame which is another embodiment of the present invention.

FIG. 4 is a plan view showing a manufacturing process of a semiconductor device using a lead frame which is another embodiment of the present invention.

FIG. 5 is a plan view showing a manufacturing process of a semiconductor device using a lead frame which is another embodiment of the present invention.

FIG. 6 is a plan view showing a manufacturing process of a semiconductor device using a lead frame which is another embodiment of the present invention.

FIG. 7 is a plan view showing a lead frame which is another embodiment of the present invention.

FIG. 8 is a lead frame B of another embodiment of the present invention.
FIG. 6 is an enlarged cross-sectional view showing a cross section taken along arrow B.

[Explanation of symbols]

 1 lead frame 2 tab 3 tab suspension lead 4 frame 4a hole 4b hole 5 lead 5a outer lead 5b inner lead 6 dam bar 7 chip 8 bonding wire 9 resin encapsulant 10 lead frame

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taku Kikuchi 2326 Imai, Ome-shi, Tokyo Hitachi, Ltd. Device Development Center

Claims (8)

[Claims] 1. A lead frame having a tab on which a chip on which a semiconductor element is formed is mounted, and a plurality of leads including an outer lead and an inner lead being arranged toward the inside of the frame. The lead frame is provided with a dam bar made of a solder material embedded between the leads at the boundary between the outer lead and the inner lead in the lead. 2. The lead frame according to claim 1, wherein the dam bar has a thickness equal to or larger than a thickness of the lead. 3. The lead frame according to claim 1 or 2, wherein the dam bar is made of a solder that does not melt at least in a resin sealing step. 4. The lead frame according to claim 1, wherein the dam bar is made of a solder that does not melt in a pellet bonding process, a wire bonding process and a resin sealing process. 5. A chip on which a semiconductor element is formed is fixedly attached to a tab of the lead frame according to claim 1, 2, 3 or 4, and a connection electrode on the surface of the chip and an inner lead of the lead frame are provided. Is connected by a bonding wire, and at least the chip and the inner lead are packaged by a resin sealing body. 6. A step of mounting a chip having a semiconductor element formed on a tab of a lead frame having a dam bar made of solder, and fixing the chip to the tab, and using a wire bonding device A step of connecting the connection electrodes on the surface of the chip and the inner leads of the lead frame with a bonding wire, and using a resin sealing device, set the lead frame in a molding die and apply a resin for sealing. Forming a resin encapsulant by press-fitting into the cavity of the molding die, packaging at least the chip and the inner leads, and heating the dam bar to melt the solder, which is the material of the dam bar, And a step of removing the dam bar from the lead in the lead frame. Manufacturing method. 7. A step of mounting a chip having a semiconductor element formed on a tab of a lead frame and fixing the chip to the tab, and a connection electrode on the surface of the chip and the connection electrode using a wire bonding device. A step of connecting the inner lead of the lead frame with a bonding wire, and, after either of the chip fixing step or the connecting step, between the outer lead of the lead frame and the plurality of leads in the boundary portion of the inner lead of the dam bar. A step of providing solder as a material, and using a resin sealing device, set the lead frame in a molding die, press the solder as a material of the dam bar by the molding die, and press the plurality of leads. After being formed into a shape embedded between Forming a resin encapsulant by press-fitting into the lead portion, packaging at least the chip and the inner lead, and heating the dam bar to melt the solder, which is the material of the dam bar, and lead in the lead frame. And a step of removing the dam bar from the semiconductor device. 8. The method of manufacturing a semiconductor device according to claim 6, wherein the step of heating the dam bar to melt the solder, which is a material of the dam bar, and removing the dam bar from the lead in the lead frame is the lead. A method of manufacturing a semiconductor device, which is performed by melting solder that is a material of a dam bar in the plating process of the lead of the frame.