JPH05315531A - Lead frame and manufacture thereof - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a lead frame and a manufacturing method thereof, which can suitably cope with high density of the lead frame and can reduce the manufacturing cost. A supporting lead frame 50 having a predetermined inner lead 52 is formed with a space for arranging a stage, and a conductor thin film is etched or pressed to form a tip portion of the inner lead and a peripheral portion of the stage. A thin film lead frame having a connection lead 32 for connection between the thin film lead frame and the connection lead of the thin film lead frame is formed so as to be electrically insulated from the thin film lead frame.
0 is adhered and supported, and the heat dissipation plate to which the connection lead is joined is aligned with the inner lead of the support lead frame 50 to join the respective connection lead 32 and the inner lead 52.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame and its manufacturing method.

[0002]

2. Description of the Related Art With the increase in the number of pins of semiconductor chips, the density of lead frames is further increasing, and there is a demand for a lead frame in which a very large number of leads are formed in a minute area. The lead frame forms a predetermined pattern by etching or pressing, but the minimum lead pitch that can be manufactured is about 60% of the thickness of the lead frame material used, so the minimum lead pitch is the lead frame material used. Limited by the material thickness of.
Since the lead frame needs to have a certain strength, a material having a certain thickness or more is used. The thinnest material used recently is about 0.127 mm.

As described above, since the material thickness used as the lead frame material is limited to a certain thickness or more, the minimum lead pitch that can be formed is inevitably determined in the case of the conventional manufacturing method. Therefore, in order to enable further miniaturization, a method using a TAB tape is performed. Figure 15
Is a conventional example of a lead frame using a TAB tape. In this example, a TAB tape 14 formed in a rectangular frame shape is adhered onto the stage 12 of the lead frame 10 to
The conductor pattern 16 extending outward from the base film of the AB tape 14 is joined to the lead 18 of the lead frame 10. The semiconductor chip 20 is bonded to the stage 12, and the semiconductor chip 20 and the conductor pattern 16 are connected by wire bonding. This lead frame has an advantage that a very thin conductor thin film can be used as a conductor pattern by using a TAB tape, and thereby a fine conductor pattern can be formed to achieve high density. When using the TAB tape, the leads 18 of the lead frame are formed in an area with a sufficient space, and the stage 12 and the leads 18 are formed.
In the micro area in the middle of, the wiring pattern is formed with high density using the TAB tape.

[0004]

As described above, the method of using the TAB tape as an intermediate connector in a portion where an extremely high density pattern is required, such as the inner lead portion of the lead frame, is a high density lead frame. However, since the TAB tape has a conductive pattern formed on a base film such as a polyimide film, it has a large number of manufacturing steps and a high manufacturing cost. Therefore, from the viewpoint of manufacturing a lead frame in mass production, there is a demand for a lead frame manufacturing method that can be miniaturized at a lower cost. The present invention has been made to solve the above problems, and an object of the present invention is to provide a lead frame that can be suitably adapted to high density of the lead frame and can reduce the manufacturing cost, and a manufacturing method thereof. To provide.

[0005]

The present invention has the following constitution in order to achieve the above object. That is, a heat dissipation plate that also serves as a stage is separately formed on a support lead frame in which an inner lead is formed with a space for arranging a stage, and a conductor is provided between the tip side of the inner lead and the peripheral edge of the heat dissipation plate. The connecting lead formed of a thin film is electrically connected to the inner lead and is electrically insulated and joined to the heat sink. Further, in the method of manufacturing a lead frame, a support lead frame having a predetermined inner lead is formed with a space for arranging a stage, while a conductor thin film is etched or pressed to form a tip portion of the inner lead. And forming a thin film lead frame having a connection lead for connecting between the peripheral part of the stage, electrically insulating the connection lead of the thin film lead frame and adhering and supporting a heat sink also serving as a stage, The heat dissipation plate to which the connection leads are joined is aligned with the inner leads of the support lead frame to join the respective connection leads to the inner leads. In addition, a support lead frame having a predetermined inner lead is formed with a space for arranging the stage, while a conductor thin film is subjected to etching processing or press processing so that the space between the tip of the inner lead and the peripheral edge of the stage is formed. Forming a thin film lead frame having a connecting lead for connecting the connecting lead and a connecting portion for connecting the leading end sides of the adjacent connecting leads, superposing the thin film lead frame on the supporting lead frame, and connecting to the leading end of the inner lead. The leads are joined, the connection leads are separated from the thin film lead frame, the connection leads are supported by the inner leads, the connecting portion on the tip side of the connection leads supported by the inner leads is removed, and the connection leads are electrically connected. Insulate and adhere to a heat sink that also serves as a stage, and attach the heat sink to the supporting lead frame It is characterized in. In addition, a support lead frame having a predetermined inner lead is formed with a space for arranging the stage, while a conductor thin film is subjected to etching processing or press processing so that the space between the tip of the inner lead and the peripheral edge of the stage is formed. Forming a thin film lead frame having a connecting lead for connecting the connecting lead and a connecting portion for connecting the leading end sides of the adjacent connecting leads, superposing the thin film lead frame on the supporting lead frame, and connecting to the leading end of the inner lead. The leads are joined, the connecting leads are separated from the thin film lead frame, the connecting leads are supported on the inner leads, the connecting leads are electrically insulated, and the supporting lead frame is adhesively supported, and the supporting lead frame has a radiator plate. Is attached and the connecting portion is removed to make each lead independent. It is effective to provide a notch in advance at the boundary between the connecting lead and the connecting part and remove the connecting part at the notch part.After joining the heat sink that also serves as a stage to the connecting lead, press the connecting part to remove the connecting part. Is effective to remove with the heat sink. Further, it is characterized in that the heat radiating plate which also serves as a stage is shaped like a frame.

[0006]

Since the thin film lead frame is formed by etching or pressing a thin film conductor, the connecting leads can be easily formed in a fine pattern. By connecting the heat dissipation plate also serving as the stage and the inner lead with the connecting lead, the lead can be easily formed at a portion close to the stage where the lead is formed with high density. Further, by using a thin film lead frame in which adjacent connecting leads are connected by a connecting portion, the connecting leads may be deformed during handling such as when the thin film lead frame is superposed on the supporting lead frame to join the connecting leads. Can be prevented, and the connection lead can be accurately joined to the inner lead.

[0007]

Embodiments of a lead frame and a manufacturing method thereof according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a plan view showing an embodiment of a thin film lead frame 30 used for manufacturing a lead frame according to the present invention.
The thin film lead frame 30 uses a metal thin film such as copper as a processing material, and is formed by etching or pressing the metal thin film to form a lead pattern having predetermined connection leads 32. The thin film lead frame 30 has connection leads 32 in a repeating pattern similar to the manufacture of a lead frame using a conventional lead frame material.
A lead pattern is formed on. Since the thin film lead frame of the embodiment is used for a quad type lead frame, the connection leads 3 are provided in four directions around the stage arrangement position.
2 are arranged. The thin film lead frame is formed according to the type of lead frame to be manufactured, and is not limited to the quad type. In manufacturing the thin film lead frame 30, the conventional method for manufacturing a lead frame can be used as it is, and necessary surface treatment such as plating is performed in advance.

Next, the thin film lead frame 30 shown in FIG.
The heat sink 40 shown in FIG. The heat dissipation plate 40 also serves as a stage on which a semiconductor chip is mounted, and an insulator 42 for joining and supporting the connection lead 32 is provided on the peripheral edge portion on one surface. As the insulator 42, one having an electrically insulating adhesive applied, or one having an electrically insulative tape applied with adhesive on both sides can be used. FIG. 3 shows the thin film lead frame 30 and the heat dissipation plate 40 described above.
Shows the state of joining after being determined. The tip of the connection lead 32 is adhered to and supported by the insulator 42 of the heat dissipation plate 40. The heat dissipation plate 40 is bonded to the thin film lead frame 30 in this way, and the connection lead 32 is cut at a position separated from the outer peripheral edge of the heat dissipation plate 40 by a predetermined distance to obtain the heat dissipation plate 40 to which the connection lead 32 shown in FIG. 4 is bonded. Connection lead 32
Is adhered to the insulator 42 of the heat dissipation plate 40 so as to extend radially outward from the peripheral portion of the heat dissipation plate 40 as shown in the figure. The bonding of the heat sink 40 and the disconnection of the connection leads 32 shown in FIGS. 3 and 4 are performed as a series of steps in the actual process. The heat sink 40 is bonded to the connection leads 32 and the connection leads 32 are bonded together. Detach.

Next, the heat dissipation plate 4 to which the connection leads 32 are adhered
0 is bonded to the supporting lead frame 50. FIG. 5 shows the heat dissipation plate 4 in which the connection leads 32 are bonded to the support lead frame 50.
It is a state where 0 is joined. The supporting lead frame 50 has a predetermined inner lead 52 and outer lead 5 formed by etching or pressing a normal lead frame material.
4, the pattern of the stage support bar 56 and the like is formed. The heat dissipation plate 40 aligns the connection leads 32 and the inner leads 52 with respect to the support lead frame 50, and joins the connection leads 32 to the inner leads 52. At this time, the corner portions of the heat sink 40 are also joined to the stage support bar 56 to support the heat sink 40 on the support lead frame 50. The connection leads 32 are formed in the same number and lead pitch as the inner leads 52 formed on the support lead frame 50, and the connection leads 32 and the inner leads 52 are aligned and connected as described above. As a result, it is possible to obtain a lead frame in which the peripheral edge of the heat sink 40 and the inner lead 52 are connected by the connecting lead 32.

The lead frame thus obtained has a shape in which the connecting lead 32 is connected between the outer circumference of the heat sink 40 also serving as a stage and the inner lead 52, and the inner lead 52 is arranged at a position separated from the heat sink 40. .. Since the connection leads 32 are formed of a thin film conductor, they can be easily formed in high density, and the inner leads 52 are formed apart from the outer periphery of the heat dissipation plate 40 to allow a space to be provided, which is easy by using a conventional lead frame material. Can be formed. FIG. 6 is a cross-sectional view showing a state in which the semiconductor chip 60 is mounted on the lead frame and is resin-sealed. The semiconductor chip 60 is bonded onto the heat dissipation plate 40 and is connected to the connection lead 32 by wire bonding. Since the connection lead 32 is supported by the heat dissipation plate 40 via the insulator 42, wire bonding can be suitably performed.

7 to 10 are explanatory views showing another embodiment of the lead frame manufacturing method. In this embodiment, as shown in FIG. 7, the thin film lead frame 30 is connected to the connecting leads 32.
When forming, the connecting portion 34 for connecting the tip portions of the adjacent connection leads 32 to each other is formed.
Since the thin film lead frame 30 is formed of a thin film conductor, the strength of the leads is low. The connecting portion 34 is for connecting the connecting leads 32 to hold the front end side of the connecting lead 32 and hold the front end portion so as not to be dislocated or deformed. Thin film lead frame 3 thus formed
0 is superposed on the supporting lead frame 50, the connecting lead 32 is joined to the inner lead 52 of the supporting lead frame 50, and the tip end side of the connecting lead 32 is separated from the thin film lead frame 30 to be supported. FIG. 8 shows a state in which the connection lead 32 is joined to the inner lead 52. The tip ends of the connection leads 32 are connected by a connecting portion 34.
The support lead frame 50 is formed by forming a predetermined pattern of the inner lead 52, the outer lead 54, the stage support bar 56, etc. using a normal lead frame material as described above. The stage is not formed on the supporting lead frame 50.

After the connecting lead 32 is joined to the inner lead 52 as described above, the connecting portion 34 is removed by pressing. FIG. 9 shows the state after removing the connecting portion 34. By removing the connecting portion 34, each lead becomes independent. The connecting portion 34 is effective in accurately joining the connecting lead 32 to the inner lead 52 when connecting the connecting lead 32 to the inner lead 52. Next, the heat dissipation plate 40 that also serves as a stage is joined to the support lead frame 50 to which the connection leads 32 are connected. FIG. 10 shows the vicinity of the tips of the inner leads 52 with the heat sink 40 joined. The connection lead 3 is provided on the periphery of the heat sink 40.
An insulator 42 for adhering and supporting 2 is provided. The insulator 42 electrically insulates the tip of the connection lead 32 from the heat dissipation plate 40 and adheres and supports it. Thus, like the lead frame of the above-described embodiment, the heat dissipation plate 40 also as a stage formed separately from the support lead frame 50.
It is possible to obtain a lead frame which has the heat dissipation plate 40 and the inner lead 52 and which is connected by the connection lead 32.

When the connecting lead 32 is connected by the connecting portion 34, the connecting portion 34 needs to be removed in a later step in order to separate the leads. In the above embodiment, after connecting the connection lead 32 to the inner lead 52, the connecting portion 34
11, the notch 36 is formed at the boundary between the connecting portion 34 and the connecting lead 32 when the thin film lead frame 30 is formed, and the inner lead 52 is connected to the connecting lead 32 as shown in FIG. Notch 3 after joining
The connecting portion 34 may be deleted by bending the six portions. Further, as shown in FIG. 12, after connecting the connection lead 32 to the inner lead 52 and further connecting the heat dissipation plate 40 to the connection lead 32, the notch 36 and the connecting portion 34 are formed.
May be removed. As yet another method, as shown in FIG. 13, after the heat dissipation plate 40 is joined to the connection lead 32, the connecting portion 34 may be punched together with the heat dissipation plate 40 by press working to make each lead independent. In FIG. 13, the portion A is the punching range. Heat sink 40
Is supported by the connection lead 32 and the stage support bar 56, and thus is supported by the support lead frame 50 even after the connecting portion 34 is punched out.

In each of the above embodiments, the supporting lead frame 50 is used.
The heat dissipation plate 40 in the form of a metal plate is provided on the above to enable mounting of the semiconductor chip and support the connection lead 32.
As shown in FIG. 4, the frame-like support 70 may be used to support the connection leads 32. Also in this case, an insulator 42 for adhesively supporting the connection lead 32 is provided on the outer peripheral edge of the frame-shaped support body 70. As a method of mounting a semiconductor chip when the frame-shaped support body 70 is used, a semiconductor chip larger than the rectangular size of the inner edge of the support body 70 is mounted and connected to the connection lead 32 by wire bonding. , A method in which an insulating sheet is stretched over the opening of the supporting body 70, a semiconductor chip is mounted on the insulating sheet and is connected by wire bonding, and a semiconductor chip having substantially the same size as the supporting body 70 is used to directly connect the connecting leads 32 with bumps. It is possible to do so.

As shown in each of the above embodiments, the lead frame according to the present invention is suitable for high density by arranging the connecting leads 32 formed of a thin film conductor in the vicinity of the stage where the leads are arranged in high density. It is possible to deal with Further, the conventional method for manufacturing a lead frame, which is formed by etching or pressing a metal plate body, can be directly applied to the manufacture of the thin film lead frame 30, and it can be easily manufactured and the production cost can be reduced. There are advantages. Further, by holding the connection leads by the heat sink 40 or connecting the connection leads 32 with each other by the connecting portion 34, it is possible to prevent deformation of the connection leads formed in a fine pattern, and thus it is possible to manufacture a finer lead pitch. It is possible to preferably manufacture a lead frame having Although the present invention has been variously described with reference to the preferred embodiments, the present invention is not limited to the above embodiments, and many modifications can be made without departing from the spirit of the invention. That is.

[0016]

As described above, according to the lead frame and the manufacturing method thereof according to the present invention, a lead frame having a higher density lead pattern can be obtained by utilizing the conventional manufacturing method of the lead frame. In comparison with the case where the TAB tape is used, it can be manufactured at a lower cost, and so on.

[Brief description of drawings]

FIG. 1 is a plan view of a thin film lead frame used in manufacturing a lead frame.

FIG. 2 is a plan view of a heat dissipation plate.

FIG. 3 is an explanatory diagram showing a state in which a heat dissipation plate is joined to a thin film lead frame.

FIG. 4 is an explanatory view showing a state in which the connection lead is separated from the thin film lead frame.

FIG. 5 is an explanatory diagram of a state in which a heat dissipation plate is connected to the support lead frame.

FIG. 6 is a sectional view showing a state in which a semiconductor chip is mounted on a lead frame.

FIG. 7 is a plan view of another embodiment of the thin film lead frame.

FIG. 8 is an explanatory diagram showing a state in which the connection lead is joined to the support lead frame.

FIG. 9 is an explanatory diagram of a state in which a connecting portion is removed.

FIG. 10 is an explanatory diagram of a state in which heat dissipation plates are joined.

FIG. 11 is an explanatory diagram in which a notch is provided in a connection lead.

FIG. 12 is an explanatory diagram showing a state in which a heat dissipation plate is joined to a supporting lead frame.

FIG. 13 is an explanatory diagram showing a press removal position of a connecting portion.

FIG. 14 is an explanatory diagram showing a state where the supports are joined.

FIG. 15 is an explanatory diagram showing a conventional example of a lead frame.

[Explanation of symbols]

 30 thin film lead frame 32 connection lead 34 connecting part 36 notch 40 heat sink 42 insulator 50 support lead frame 52 inner lead 54 outer lead 56 stage support bar 60 semiconductor chip 70 support

Claims (7)

[Claims] 1. A support lead frame in which an inner lead is formed with a space for arranging a stage, and a heat radiating plate that is also formed as a separate member is provided on the tip side of the inner lead and on the peripheral edge of the heat radiating plate. A lead frame, characterized in that a connection lead formed from a conductive thin film is electrically connected to an inner lead and electrically insulated and joined to a heat dissipation plate. 2. A support lead frame having a predetermined inner lead is formed with a space for arranging the stage being formed. On the other hand, a conductor thin film is etched or pressed to form a tip portion of the inner lead and a peripheral portion of the stage. Forming a thin film lead frame having a connecting lead for connection between the thin film lead frame and the connecting lead of the thin film lead frame and adhering and supporting a heat radiating plate that also serves as a stage, and the connecting lead is joined. A method of manufacturing a lead frame, wherein the heat dissipation plate is aligned with the inner leads of the supporting lead frame, and the connection leads and the inner leads are respectively joined. 3. A support lead frame having a predetermined inner lead is formed by leaving a space for arranging the stage, and a conductor thin film is etched or pressed to form a tip portion of the inner lead and a peripheral portion of the stage. Forming a thin film lead frame having a connecting lead for connecting between the connecting lead and the connecting lead, and a connecting portion for connecting the leading end side of the adjacent connecting lead, and stacking the thin film lead frame on the supporting lead frame, The connection lead is joined to the tip, the connection lead is separated from the thin film lead frame, the connection lead is supported by the inner lead, the connecting portion on the tip side of the connection lead supported by the inner lead is removed, and the connection lead is removed. It is electrically insulated and adhesively supported on a heatsink that also serves as a stage, and a heatsink on the support lead frame Method for fabricating a lead frame, characterized in that mounting. 4. A support lead frame having a predetermined inner lead is formed with a space for arranging a stage being formed. On the other hand, a conductor thin film is etched or pressed to form a tip portion of the inner lead and a peripheral portion of the stage. Forming a thin film lead frame having a connecting lead for connecting between the connecting lead and the connecting lead, and a connecting portion for connecting the leading end side of the adjacent connecting lead, and stacking the thin film lead frame on the supporting lead frame, The connection lead is joined to the tip, the connection lead is separated from the thin film lead frame, the connection lead is supported by the inner lead, the connection lead is electrically insulated, and the connection lead is adhesively supported on the heat dissipation plate that also serves as the stage, and the support lead frame A heat dissipation plate is attached to each of the leads, and the connecting portion is removed to make each lead independent. Method of manufacturing over de frame. 5. The method for manufacturing a lead frame according to claim 3, wherein a notch is provided in advance at the boundary between the connection lead and the connecting portion, and the connecting portion is deleted at the notch portion. 6. The method of manufacturing a lead frame according to claim 4, wherein after the heat dissipation plate which also serves as the stage is joined to the connection lead, the connecting portion is removed together with the heat dissipation plate by pressing. 7. The method of manufacturing a lead frame according to claim 1, wherein the heat radiating plate which also serves as a stage has a frame shape.