JPH06181281A - Multilayer lead frame - Google Patents

Abstract

PURPOSE:To provide a multilayer lead frame in which a decoupling capacitor having stable and sufficient capacity can be formed. CONSTITUTION:A multilayer lead frame has a signal layer 10, a power source layer 12 and a ground layer 14 laminated through insulating layers 16, 18 to be superposed on an inner lead of the layer 10, and comprises a chip capacitor 22 for forming a decoupling capacitor to be arranged between the layers 12 and 14 in a through hole 20 provided at positions of superposed layers 12 and 18 of the layer 14.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to multilayer lead frames.

[0002]

2. Description of the Related Art As shown in FIG. 8, there is known a multilayer lead frame in which a signal layer 10, a power source layer 12, and a ground layer 14 are laminated in a three-layer structure with insulating sheets 16 and 18 interposed therebetween. Although not shown, the power supply layer 12 and the ground layer 14 are connected to predetermined leads in the signal layer 10. According to this multilayer lead frame, not only the number of pins can be increased by separately providing the power supply layer and the ground layer, but also the power layer 12 and the ground layer 14 having a large area apart from the signal layer 10 are provided in the package. Crosstalk can be suppressed for the layer 10 as a strip line, and there is an advantage that power supply noise can be reduced because the inductance is low for the power supply system.

[0003]

By the way, in order to reduce the power supply noise, it is preferable to form a decoupling capacitor between the power supply layer 12 and the ground layer 14. Therefore, conventionally, the power supply layer 12 and the ground layer 14 are laminated via an insulating sheet 18 having a large dielectric constant, and a decoupling capacitor is provided at a portion where the power supply layer 12 and the ground layer 14 overlap each other. To be formed.
However, the insulating sheet 18 is applied to the surface of the layer by PVD or CV.
When a decoupling capacitor is formed by depositing a thin film by vapor phase growth method such as D method or sputtering, it is difficult to accurately adjust the capacitance of the capacitor. Further, the formation of high dielectric ceramics into a thin film on the surface of the layer by sputtering or the like has been examined, but there is a problem that the cost becomes high.

Therefore, the present invention has been made to solve the above problems, and an object thereof is to provide a multilayer lead frame capable of forming a stable and sufficient decoupling capacitor.

[0005]

The present invention has the following constitution in order to achieve the above object. That is, in a multi-layer lead frame in which a signal layer, a power supply layer, and a ground layer are stacked on an inner lead of a signal layer and laminated with an insulating layer in between, a portion overlapping with the insulating layer of the power supply layer and the ground layer It is characterized in that a chip capacitor serving as a decoupling capacitor between the power supply layer and the ground layer is disposed in the provided through hole. The chip capacitor is arranged in the through hole provided over the power supply layer, the insulating layer, and the ground layer,
Electrodes may be electrically connected and fixed to the power supply layer and the ground layer with a conductive adhesive. The chip capacitor is arranged in the through hole provided over the outer layer and the insulating layer of the power supply layer and the ground layer, and has a large number of small holes for the inner layer. Thermocompression bonding is performed by the adhesive tape via a thermoplastic adhesive tape in which metal conductors slightly projecting on the front and back sides of the tape are embedded, and the electrodes are electrically conducted by the metal conductor, and with respect to the outer layer. The electrode can be electrically conducted and fixed by a conductive adhesive. The chip capacitor is arranged in the through hole provided in the insulating sheet between the power supply layer and the ground layer, and has a plurality of small holes for the power supply layer and the ground layer, and the tape front and back surfaces are provided in the small holes. It is possible to perform thermocompression bonding with the insulating tape via a thermoplastic insulating tape in which a metal conductor protruding slightly to the inside is embedded, and to electrically connect the electrodes with the metal conductor.

[0006]

According to the multi-layer lead frame of the present invention, since the chip capacitor whose capacitance is adjusted in advance is used, the capacitance as the decoupling capacitor can be accurately adjusted and provided in a required size. Further, since the chip capacitor is arranged in the through hole provided between the power supply layer and the ground layer, no special space is required and a multi-layer lead frame having a built-in decoupling capacitor can be provided. Furthermore, when the chip capacitor is fixed by using the thermoplastic adhesive tape, it is possible to easily fix the chip capacitor, and it is possible to prevent a short circuit between the electrodes as in the case of using a conductive adhesive material that easily flows such as lumps.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a first embodiment. The basic structure of the multilayer lead frame is the same as the conventional one, and the signal layer 10, the power source layer 12, the ground layer 14 are the insulating sheet 1.
It is formed by laminating three layers with Nos. 6 and 18 interposed therebetween. As shown in FIG. 2, a large number of through holes 20 through which the sealing resin can enter in order to improve the adhesion with the sealing resin are provided in the overlapping portion of the ground layer 14, the insulating sheet 18, and the power supply layer 12. Has been formed. A chip capacitor 22 as shown in FIG. 3 is provided in any of the through holes 20. Reference numerals 24 and 26 are electrodes of the chip capacitor. As the chip capacitor 22, a high dielectric constant material such as barium titanate is used as a dielectric, and a small size and a large capacity can be used. The chip capacitor 22 is inserted into the through hole 20, and the electrodes 24 and 26 are made of a conductive adhesive material 28.
Are electrically connected to and fixed to the power supply layer 12 and the ground layer 14, respectively.

The present embodiment is constructed as described above.
In this embodiment, since the chip capacitor 22 whose capacity is adjusted in advance is used, the capacity as the decoupling capacitor can be accurately adjusted and provided in a required size. For example, the capacity of a chip capacitor with a diameter of 1 mm is about 200 pF, 2 mm is 900 pF, and 3 mm.
2000pF, 4mm 3000pF, and 5mm 5000pF, so to achieve the capacity of 10,000pF required as a decoupling capacitor, use the required number of chip capacitors 22 according to the diameter of each chip capacitor. Good. Further, in this embodiment, since the chip capacitor 22 is arranged by utilizing the through hole 20 into which the sealing resin enters, it is possible to provide a multilayer lead frame having a built-in decoupling capacitor without requiring a special space.

FIG. 4 shows a second embodiment. In this embodiment, a thermoplastic adhesive tape 30 with a via as shown in FIG. 5 or 6 is used. This thermoplastic adhesive tape 30
Is formed with a large number of small holes 32 in a base material 31 made of a thermoplastic adhesive film such as polyimide. In the small holes 32, a metal conductor 33 such as gold is formed so as to slightly project to the front and back surfaces of the base material 31.
(Via) is embedded. In addition, in the one shown in FIG. 6, a metal conductor having a nickel surface plated with gold is used. In this embodiment, the power supply layer 12 is not provided with the through holes, but the insulating sheet 18 and the ground layer 14 are provided with the through holes 20. The chip capacitor 22 is placed in the through hole 20.
And the electrode 24 and the power supply layer 12 are fixed by using the above-mentioned thermoplastic adhesive tape 30, and the electrode 26 and the ground layer 14 are fixed by the conductive adhesive 2 as in the above embodiment.
8 is used to establish electrical continuity and is fixed. As the thermoplastic adhesive tape 30 is heated and pressed, the base material 31 is softened and the power supply layer 12,
The electrodes 24 come into contact with each other, and when cooled, the adhesive force increases to bond them. At the same time, the metal conductor 33 is the power supply layer 1
2. Contacting the electrode 24, electrical connection is established between them.
In this embodiment, since the thermoplastic adhesive tape 30 is used to fix the power supply layer 12 on the inner bottom surface side of the through hole 22 and the electrode 24, the two can be easily fixed, or the flow of fuzz or the like occurs. It is possible to prevent a short circuit between electrodes as in the case of using an easily conductive adhesive.

FIG. 7 shows a third embodiment. In this embodiment, the fixing between the electrode 26 and the ground layer 14 is also performed by using the thermoplastic adhesive sheet 30. That is, the through hole 20
Is provided only on the insulating sheet 18, and the chip capacitor 22 is provided in the through hole 20 in the assembly process of the multilayer lead frame.
And the signal layer 10, the power supply layer 12, and the ground layer 14 are overlapped with the insulating sheets 16 and 18 interposed therebetween, and the layers are heated and pressed to thermocompress each layer by the insulating sheets 16 and 18, and the chip capacitor 22 is also provided. Is also thermocompression-bonded to the power supply layer 12 and the ground layer 14 with the thermoplastic adhesive tape 30, and both electrodes are electrically connected to the power supply layer 12 and the ground layer 14. In this embodiment, the conductive adhesive does not flow out at all, and at the same time, the chip capacitor 22 can be fixed at the same time as the heating / pressurizing step of each layer 10, 12, 14. In each of the above embodiments, the signal layer 10, the power supply layer 12, and the ground layer 14 are laminated in this order, but the signal layer 10, the ground layer 14, and the power supply layer 12 are laminated in this order, and between the ground layer 14 and the power supply layer 12. A decoupling capacitor may be formed in the same manner as described above.

Although the present invention has been variously described with reference to the preferred embodiments, the present invention is not limited to these embodiments, and many modifications can be made without departing from the spirit of the invention. Of course.

[0012]

According to the multi-layer lead frame of the present invention, since the chip capacitor whose capacity is adjusted in advance is used, the capacity as the decoupling capacitor can be accurately adjusted and provided. Further, since the chip capacitor is arranged in the through hole provided between the power supply layer and the ground layer, no special space is required and a multi-layer lead frame having a built-in decoupling capacitor can be provided. Furthermore, when the chip capacitor is fixed by using the thermoplastic adhesive tape, it is possible to easily fix the chip capacitor, and it is possible to prevent a short circuit between the electrodes as in the case of using a conductive adhesive material that easily flows such as lumps.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a first embodiment.

FIG. 2 is a bottom view of the multilayer lead frame according to the first embodiment.

FIG. 3 is a perspective view of a chip capacitor.

FIG. 4 is a partial sectional view showing a second embodiment.

FIG. 5 is a sectional view of a thermoplastic adhesive tape.

FIG. 6 is a cross-sectional view of a thermoplastic adhesive tape.

FIG. 7 is a sectional view showing a third embodiment.

FIG. 8 is a perspective view showing a conventional multilayer lead frame.

[Explanation of symbols]

 10 Signal Layer 12 Power Supply Layer 14 Ground Layer 16 Insulating Sheet 18 Insulating Sheet 20 Through Hole 22 Chip Capacitor 24 Electrode 26 Electrode 28 Conductive Adhesive 30 Thermoplastic Adhesive Tape 33 Metal Conductor

Claims (4)

[Claims] 1. A multi-layer lead frame comprising a signal layer, a power supply layer, and a ground layer, which are stacked on an inner lead of the signal layer and laminated via an insulating layer, wherein the power layer and the ground layer are overlapped with each other via the insulating layer. A multilayer lead frame, characterized in that a chip capacitor, which is a decoupling capacitor between a power supply layer and a ground layer, is provided in a through hole provided in a portion where the lead frame is provided. 2. The chip capacitor is arranged in the through hole provided over a power supply layer, an insulating layer, and a ground layer,
The multilayer lead frame according to claim 1, wherein electrodes are electrically connected to and fixed to the power supply layer and the ground layer with a conductive adhesive. 3. The chip capacitor is arranged in the through hole provided over the outer layer and the insulating layer of the power supply layer and the ground layer, and has a large number of small holes for the inner layer. The thermocompression bonding is performed by the adhesive tape via a thermoplastic adhesive tape in which a metal conductor slightly protruding on the front and back of the tape is embedded in the small hole, and the electrode is electrically conducted by the metal conductor. 2. The multilayer lead frame according to claim 1, wherein electrodes are electrically connected to and fixed to the outer layer by a conductive adhesive. 4. The chip capacitor is disposed in the through hole provided in the insulating sheet between the power supply layer and the ground layer, and has a large number of small holes for the power supply layer and the ground layer. It is characterized in that the metal tape is thermocompression bonded by the insulating tape via a thermoplastic insulating tape in which a metal conductor projecting slightly on the front and back of the tape is embedded in the hole, and the electrode is electrically conducted by the metal conductor. The multilayer lead frame according to claim 1.