JP3241471B2 - Lead frame - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame,
More specifically, it is covered with outer leads and mold resin.
Dam bar in the boundary portion between the inner lead and dividing are provided, and the metal planes inner lead and the semiconductor chip is mounted about the lead frames which are joined together via the resin film.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 7 , a plurality of inner leads 102 are formed on a lead frame 100 to be connected to a semiconductor chip to be mounted. It is connected to the outer lead 104. Such a lead frame 100
When a semiconductor device is mounted on a semiconductor chip and a semiconductor device is manufactured, as shown in FIG. 8 , a metal plane 120 bonded to the inner lead 102 via the resin film 110 is used.
After mounting the semiconductor chip 112, the semiconductor chip 1
12 is connected to the tip of the inner lead 102 by a wire 114. Next, the semiconductor chip 112, the wire 114,
And the inner lead 102, that is, the dam bar 106
The area enclosed by is molded with resin. At this time, the dam bar 106 is provided so that the resin filled in the cavity formed by the molds 116 and 118 does not leak from the gap between the leads to the outer lead 104 side. Conventionally, such a dam bar 106 is
Since the inner leads 102 and the outer leads 104 are made of metal, a tie bar cut for cutting the portion between the leads of the dam bar 106 is performed after resin molding to secure insulation between the leads.

However, recently, the lead pitch is becoming finer in order to respond to the demand for more pins in a lead frame accompanying higher integration of semiconductor chips. For this reason,
Tie bar cutting work after resin molding is becoming difficult. On the other hand, as a tie bar that does not require such a tie bar cutting operation, use of a plastic tie bar formed in a predetermined shape in advance has been attempted.

[0004]

By using such a plastic tie bar, a tie bar cutting operation can be omitted. However, since the shape of the lead formed differs for each lead frame, it is necessary to previously form a plastic tie bar having a shape suitable for the lead frame to be used, and the management of the plastic tie bar becomes complicated. Moreover, inserting a plastic tie bar into a lead frame having a fine lead pitch is an extremely complicated preparation operation. Therefore, an object of the present invention is to provide a lead frame which can eliminate the need for a tie bar cutting operation and can eliminate complicated management and preparation operations.

[0005]

Means for Solving the Problems As a result of repeated studies to achieve the above object, the present inventors have extended the resin film and metal plane bonded to the inner leads to the outer lead portions near the tie bars. By applying a solder resist on the resin film by screen printing to form a tie bar, the tie bar can be easily formed, and complicated management and preparation like a plastic tie bar formed in a predetermined shape in advance can be performed. The inventors have found that work can be made unnecessary, and arrived at the present invention. That is, in the present invention, a dam bar is provided at the boundary between the outer lead and the inner lead covered by the mold resin, and the inner lead and the metal plane on which the semiconductor chip is mounted are integrally joined via a resin film. In the lead frame, the resin film is formed so as to extend to the outer lead portion, and the dam bar is formed in a lead gap located on the resin film at a boundary between the inner lead and the outer lead. Ri from an electrically insulating material such as the formed solder resist or adhesive formed, metallic play covered by the mold resin
Resin corresponding to the metal part and the metal plane part
In the film part, the metal plain and resin film
Is formed, and a slit is formed through the metal plate.
Inner lead at the edge of the slit formed in the lane
In the lead frame, characterized in Rukoto have connection pieces which are connected is formed with.

In the present invention, a resin film and gold
One or both of the metal planes
-By extending to the lead portion, the heat dissipation of the finally obtained semiconductor device can be improved. Further , in the lead frame of the present invention, since the resin film extends to the outer lead portion, a test pad can be formed on the outer lead portion located on the resin film. By forming such a test pad, a probe used for circuit inspection or the like can be easily pressed against the test pad after assembly is completed, and the circuit inspection operation can be facilitated.

[0007]

According to the present invention, since you have extended the resin film is bonded to the inner lead to the outer lead portion, the gap between the lead located in a position to and place on a resin film, a solder Electricity such as resist and adhesive
A dam bar made of an electrically insulating material can be formed. Therefore, as previously conventional in advance by molding into a predetermined shape of the plastic dam bar, without requiring complicated control and preparation, it can be formed easily dam bar having an electrical insulating property.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The lead frame of the present invention will be described in more detail with reference to the drawings. FIG. 1 is a partial cross-sectional view showing an embodiment of the present invention.
Is a semiconductor chip 22 and a wire 2 mounted on a metal plane 18 (hereinafter, sometimes referred to as a plane 18).
4 and an outer lead 14 whose tip is connected to an external circuit or the like.
In the lead frame of the present embodiment, the inner leads 12 and the plane 18 are joined via a resin film 20 (hereinafter, sometimes referred to as a film 20) made of a polyimide resin. The plane 18 and the film 20 are connected to the outer lead 14 near the dam bar 16.
It is extended to a part. Such extending portion, i.e. the portion from the dam bar 16 to the end surface of the film 20 and the plane 18, at the time of resin molding, mold 3
It is the part clamped by 0,32. The inner leads 12 and the mounted semiconductor chip 22 are:
It is inserted into a cavity formed by the molds 30 and 32 and is sealed in the mold resin 26. still,
The dam bar 16 formed at the boundary between the inner lead 12 and the outer lead 14 serves as a boundary between the portion clamped by the molds 30 and 32 and the cavity.

As shown in FIG. 2, the dam bar 16 in the present embodiment has the leads 1 on the film 20 joined to the plane 18 by an adhesive layer 34 by an adhesive layer 36.
0,10 ... are joined, the solder resist 28 in the gap of the lead 10 is formed by filling. The dam bar 16 can be easily formed by bonding the lead 10 and the plane 18 by the film 20 having the adhesive layers 34 and 36 formed on both surfaces thereof, and then applying paste solder resist to a predetermined position by screen printing. Can be formed. As described above, since the dam bar 16 is formed on the plane 18 and the film 20 stacked on each other, the flatness and rigidity of the dam bar 16 made of a solder resist can be improved. Further, in this embodiment, it is extending plane 18 to the portion of the outer lead 14 that are never covered by Moruto resin, as compared with the semiconductor device shown in FIG. 10 the plane 18 is covered with the molding resin, the semiconductor device Heat dissipation characteristics can be improved.

[0010] plane 18 shown in FIG. 1, for use as a power plate or ground plate, as shown in FIG. 3, the film 20 corresponding to the portion and the portion of the plane 18 of the plane 18 which is covered by the mold resin
A slit 38 penetrating through the plane 18 and the film 20 is formed in a portion of the above, and a connection piece 40 connected to the inner lead 12 is formed at an edge of the slit 38 formed in the plane 18. By using the plane 18 shown in FIG. 4, the power lead or the ground lead and the plane 18 are connected via the connecting piece 40 as shown in FIGS . 1 and 3, and the plane 18 is connected to the power plate or the ground plate. And a multilayer lead frame can be easily formed. In the lead frame shown in FIGS. 1 and 3, a part of the outer lead 14 which is not covered by the mold resin 26 is provided on the film 20 and the plane 18, and as shown in FIG. By forming the test pads 42 on the outer leads 14 on the plane 18, the circuit inspection work after the completion of the assembly can be facilitated.

That is, in a semiconductor device using a conventional lead frame, a circuit inspection or the like is performed after a tie bar cut is performed, so that the outer leads vary and a contact failure with a circuit inspection probe occurs, and the inspection can be performed. May disappear. In this regard, in the lead frame shown in FIG. 5, the test pad 40 wider than the width of the outer lead 14 and having good flatness is bonded to the film 20, and the test pad 40 can be fixed. Therefore, the circuit inspection probe can be reliably brought into contact with the test pad 40, and the inspection can be performed easily. In addition, by grounding the plane 18, noise during inspection can be reduced. Further, by adjusting the thickness of the film 20 between the plane 18 and the leads,
Since the characteristic impedance can be adjusted to an optimum value, the inspection accuracy can be improved.

[0012]

The dam bar 16 of the lead frame shown in FIG.
Is, as shown in FIG. 2, although the solder resist 28 in the gap of the lead 10 bonded by an adhesive layer 36 on the film 20 is formed by filling, as shown in FIG. 6 (a), the paste The film 20 in which the adhesive layer 36 is thickened by thickly applying an adhesive in the shape of a letter may be pressed against the leads 10 to fill the gap between the leads with the adhesive. Further, as shown in FIG. 6 (b), between the pasty film 20 adhesive layer 36 was formed consisting of the adhesive and the film 44, the lead 1
The adhesive may be filled in the lead gap by inserting 0. Furthermore, as shown in FIG. 6 (c), the film 2
Alternatively, the solder resist 28 may be applied directly on the lead 0 to fill the lead gap with the solder resist 28. in this case,
After a thin layer of solder resist is applied on the film 20 to fix the leads 10, the solder resist can be applied to the gaps between the leads by applying the solder resist again. Alternatively, a direct solder resist over lead 10 placed on the film 20 may be applied by screen printing or the like, as in FIG. 6 (c), can be filled with a solder resist to the lead clearance.

[0014]

According to the present invention, even in a lead frame having a fine pitch, it is possible to easily form a plastic dam bar in which dam bar cut can be omitted, and therefore, it is possible to meet the demand for a fine pitch lead frame. it can.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing one embodiment of the present invention.

FIG. 2 is a sectional view showing an internal structure of the dam bar shown in FIG.

FIG. 3 is a view showing a power supply constituting the lead frame shown in FIG. 1;
Plane and inner as plate or ground plate
This shows the connection state with the lead .

4 shows a partial front view of the plane constituting the rie de frame shown in FIG.

FIG. 5 is a partial front view showing a state in which test pads are provided on outer leads.

FIG. 6 is a sectional view showing another embodiment of the dam bar.

FIG. 7 is a front view for explaining a conventional lead frame.
It is.

FIG. 8 shows a conventional lead frame clamped to a mold.
It is a partial cross section showing the state where it was locked.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 23/50 H01L 21/56 H01L 23/28

Claims (3)

(57) [Claims] 1. A dam bar is provided at a boundary between an outer lead and an inner lead covered by a mold resin, and the inner lead and a metal plane on which a semiconductor chip is mounted are integrally joined via a resin film. In the lead frame, the resin film is formed to extend to the outer lead portion, and the dam bar is formed in a lead gap located on the resin film at a boundary between the inner lead and the outer lead. Ri consists electrically insulating material such as solder resist or adhesive that is, the portion of the metal plane covered by the mold resin及
And the resin film corresponding to the metal plane part
Through the metal plane and resin film
Slits are formed and are formed in the metal plane.
Connected to the inner lead at the edge of the formed slit
The lead frame characterized by Rukoto connection piece is formed that. 2. The lead frame according to claim 1, wherein one or both of the resin film and the metal plane extend to the outer lead portion near the dam bar. 3. An outer lead portion on a resin film.
3. The lead frame according to claim 1 , further comprising a test pad formed thereon.