JP2634978B2 - Lead frame with protection element - 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 provided for electrically connecting an electronic component sealed in a package to the outside of the package, and more particularly, to a surge applied from outside the package. It is possible to protect the electronic components in the package from the voltage. It is possible to relatively increase the resistance value and the capacitance value while avoiding a decrease in the withstand voltage. The present invention relates to a lead frame with a protection element that can make a resistance value different for each lead frame.

[0002]

2. Description of the Related Art Conventionally, in an input / output circuit of a semiconductor integrated circuit, an internal circuit is electrostatically damaged by a surge voltage (electrostatic discharge) applied from a lead frame provided in a package of the semiconductor integrated circuit. Various techniques have been disclosed for preventing such a situation. Hereinafter, such a technique is also referred to as electrostatic protection.

For example, CMOS (complementary metal)
oxide semiconductor) MOS (me
tal oxide semiconductor) In an output circuit of a semiconductor integrated circuit, a P channel M used in the output circuit is used.
The output circuit is protected from static electricity by a parasitic diode formed in the OS transistor or the N-channel MOS transistor.

However, with the miniaturization of the wafer process due to the increase in the degree of integration, there is a problem that the protection capacitance of such a parasitic diode is reduced and the electrostatic protection is insufficient.

For this reason, Japanese Patent Application Laid-Open No. 63-175460 discloses a technique in which a surge protection element is provided in a package portion of a semiconductor integrated circuit. For example, Japanese Patent Application Laid-Open No. 63-175460 discloses a technique in which a surge protection element having a Zener effect is provided in a package between a lead frame of a semiconductor integrated circuit and a ground lead frame.

Japanese Unexamined Patent Application Publication No. 63-175461 discloses a technique in which a plastic protective resin, which is a package of a semiconductor integrated circuit, is used as a Zener effect resin to constitute a surge protection device.

Japanese Patent Application Laid-Open No. 64-34133 discloses a technique for protecting a semiconductor integrated circuit from static electricity by connecting a lead frame and a chip via a resistor. For example, Japanese Patent Application Laid-Open No. 64-341
No. 33 discloses a technique of performing electrostatic protection by forming a resistance element in series with an input circuit of a semiconductor integrated circuit using a bonding wire connecting a lead frame and a chip as a resistance wire.

Japanese Patent Application Laid-Open No. Sho 62-265731 discloses that, in a semiconductor integrated circuit, an electrode lead is used as a tape-like insulating film in order to easily perform an aging test for removing an initial operation failure after an assembly process. The lead frame used for the tape carrier system provided above is provided with a metal thin film resistor having one end connected to the lead, and at least two leads are connected with at least one of the leads via the metal thin film resistor. A technique of forming a lead frame having a common electrode portion is disclosed. Also, Japanese Unexamined Patent Publication No.
Then, after the aging test, the metal thin film resistor and the like are removed.

[0009]

However, the above-mentioned JP-A-63-175460 and JP-A-63-17546 are mentioned above.
1. In JP-A-64-34133, since a resistance element provided for electrostatic protection is provided in a package of a semiconductor integrated circuit or the like, the resistance element is made sufficiently large while avoiding a decrease in withstand voltage. There is a problem that it is difficult to use a resistance element having a resistance value. This problem must be noted when the electrostatic protection target is a MOS semiconductor integrated circuit. This is because in the case of a MOS semiconductor integrated circuit, the input impedance must be relatively high, and the resistance value of the resistance element for protecting the input from static electricity must be relatively high.

In addition, there is a problem that as the resistance value of the resistance element provided in the input / output circuit of the semiconductor integrated circuit for protecting the static electricity increases, the signal transmission speed in the input / output circuit portion decreases. Therefore, the resistance value of the resistance element for electrostatic protection is determined in consideration of the magnitude of the signal current and the like in consideration of the degree of electrostatic protection and the signal transmission speed.
It must be determined for each input or output of the semiconductor integrated circuit.

However, there is a problem that the resistance value of the resistance element formed by these conventional techniques cannot be adjusted for each input or output as described above.

Incidentally, the aforementioned Japanese Patent Application Laid-Open No. 62-265731
Is not a technology related to electrostatic protection.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. In a lead frame provided for electrically connecting an electronic component sealed in a package to the outside of the package, the present invention relates to a lead frame. from a surge voltage applied from the outside, it is possible to protect the electronic components of the package, while avoiding a reduction in the breakdown voltage, the coercive
Resistance of the resistive element and the capacity of the capacitive element
Can be relatively large quantity value, also capable of varying these resistance and capacitance values for each lead frame, and an object thereof is to provide a lead frame with protective elements.

[0014]

According to the present invention, there is provided a lead frame provided for electrically connecting an electronic component sealed in a package to the outside of the package . Conductive layer and resistive element
A resistance layer made of a material having a predetermined electric resistance and an insulating layer having a sufficiently high electric resistance,
The second conductive layer made of a material having a low electric resistance is stacked in this order.
A multi-layered structure, wherein the first conductive layer or
Is a capacitor using the resistive layer and the second conductive layer as counter electrodes.
The amount element is embedded and the protection element is created.
The above object has been achieved.

In a lead frame with a protection element,
By using the resistive layer, it is inserted in series in the electrical connection by the lead frame, used in the protective element
It may be fabricated the resistance element that.

[0016]

Further, in the lead frame with a protection element, the material of the resistance layer may be a material whose electric resistance changes according to an applied voltage.

[0018]

According to the present invention, there is provided a lead frame provided for electrically connecting an electronic component sealed in a package to the outside of the package. A protection element for protecting the electronic component is configured.

FIG. 1 is a perspective view showing the gist of the present invention.

In FIG. 1, a lead frame 1 to which a wire 2 for connecting to an electronic component in a package is bonded as shown by an arrow A1 is connected to the outside of the package in the direction of an arrow A2.

The lead frame 1 includes at least a first conductive layer 11, a resistance layer 14, an insulating layer 16 ,
It has a multilayer structure having a second conductive layer 12.

Further, according to the present invention, according to the lead frame having such a multilayer structure, a protection element is formed by forming a resistance element or a capacitance element by processing a cutting groove or the like with a laser or a diamond needle. It is found that it is possible.

The present invention has found a multi-layered lead frame having such a wide application range.
The processing shape and processing method for this are not limited.

The resistance element formed as a protection element in this way can have a relatively large resistance value while avoiding a decrease in withstand voltage.

This is because a relatively free space can be used within the range of the lead frame in constituting the protection element. In addition, since the lead frame has a portion exposed to the outside of the package, heat can be effectively radiated from the protection element formed in the lead frame.

In the lead frame of the present invention,
By changing the position where the cutting groove is processed by a laser, a diamond needle, or the like, the resistance value and the capacitance value of the resistance element and the capacitance element of the protection element formed by the processing can be adjusted.

When a capacitive element is formed as a protective element, the protective element by the capacitive element is connected inside the protective package, so that the conventional capacitive element has to be mounted outside the package. As compared with the above, the electrostatic protection effect and the like can be further improved.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is a side view of the first embodiment of the present invention.

In this embodiment, the number of protection elements is small.
Focus on the resistive element built to be used as a part
explain. In FIG. 2, reference numerals A1 and A2 are the same as those described above with reference to FIG.

In FIG. 2, the lead frame 1 is
It is composed of a first conductive layer 11 and a resistance layer 14.
The lead frame 1 is connected to an electronic component in the package by a wire 2 as shown by an arrow A1.

In the first embodiment shown in FIG. 2, the first conductive layer 11 includes a conductive layer portion 11a and a conductive layer portion 1.
1c. Alternatively, in this embodiment, the first conductive layer 11 is divided into a conductive layer portion 11a, a conductive layer portion 11b, and a conductive layer portion 11c. This division is performed by providing cutting grooves with laser light.

The resistance element R1 described later with reference to FIG.
If the desired resistance value is obtained, the conductive layer portion 11
It is not necessary to remove b, and in this case, the cutting width by the laser beam can be narrowed, and the processing efficiency can be improved.

FIG. 3 is a top view of the first embodiment of the present invention.

In the top view of FIG.
The conductive layer 11 is divided into a conductive layer portion 11a and a conductive layer portion 11c, or the conductive layer portion 11a and the conductive layer portion 11
The state of division into b and the conductive layer portion 11c is shown. Also, the shape of the cutting groove by laser light is shown,
The conductive layer portion 11a connected to the electronic component inside the package by the wire 2 is separated from the conductive layer portion 11c connected to the outside of the package.

FIG. 4 is an equivalent circuit of the above-described first embodiment of the present invention.

In FIG. 4, reference numerals A1 and A2 are the same as those in FIG.

As shown in FIG. 4, in the first embodiment of the present invention, a resistance element R1 functioning as a protection element is provided.
Are inserted in series in the electrical connection between the electronic component sealed in the package and the outside of the package. The resistance value of the resistance element R1 shown in FIG.
Can be adjusted by changing the length L1.

As described above, according to the first embodiment of the present invention, the resistance protection can be improved by the resistance element R1.

FIG. 5 is a side view of a second embodiment of the present invention.

In this embodiment, the number of protection elements is small.
Focus on the capacitive element built to be used as a part
explain. In FIG. 5, reference numerals A1 and A2 are the same as those described above with reference to FIG.

The lead frame according to the second embodiment of the present invention shown in FIG. 5 has a first conductive layer 11, a resistance layer 14, an insulating layer 1
6 and the second conductive layer 12 have a multilayer structure in which they are stacked in this order.

The second conductive layer 12 includes a conductive layer portion 12a
And a conductive layer portion 12b. This division is performed by laser cutting. The conductive layer portion 12a is connected to the ground GND.

FIG. 6 is a bottom view of the second embodiment of the present invention.

FIG. 6 shows the state of the divided second conductive layer 12. That is, the conductive layer portion 12a connected to the ground GND in a predetermined manner is separated from the conductive layer portion 12b and serves as a counter electrode to the first conductive layer 11 or the resistance layer.

FIG. 7 is an equivalent circuit diagram of the second embodiment of the present invention.

In FIG. 7, reference numerals A1 and A2 are the same as those described above with reference to FIG.

As shown in the equivalent circuit of FIG. 7, in the second embodiment, the first conductive layer 11 or the resistive layer 1
4 and a conductive layer portion 12a in which the second conductive layer 12 is divided and connected to the ground GND.
One is built.

According to the second embodiment of the present invention,
With the provision of the capacitor C1, the electrostatic protection of the electronic component sealed in the package can be improved.

FIG. 8 is an equivalent circuit diagram of a modification of the above-described second embodiment of the present invention.

The modified example of FIG. 8 is a modification of the above-mentioned broken line B of FIG.
The portion indicated by 1 is cut by a laser, and the first conductive layer 11 is divided into two conductive layer portions. Therefore, in this modified example, the lead frame 1 between the electronic component sealed in the package and the outside of the package is provided.
During the connection according to the above, a resistance element is formed in series. That is, as shown in the equivalent circuit diagram of FIG.
2 are built, and the capacitance elements C2 and C3
Is made.

According to such a modification of the second embodiment of the present invention, in addition to the resistive element R2, the capacitive elements C2 and C3 are also provided. The electrostatic protection effect can be more improved than in the embodiment.

FIG. 9 is a side view of a third embodiment of the present invention.

In FIG. 9, reference numerals A1 and A2 are the same as those in FIG.

The lead frame of the third embodiment shown in FIG. 9 comprises a first conductive layer 11, a resistance layer 14, and a second conductive layer 12.
It is composed of

In particular, the resistance layer 14a of this embodiment shown in FIG.
The material is in an insulated state where the electric resistance is sufficiently large at the voltage of the ordinary power supply voltage, while the electric resistance is lower at higher voltages. Is a material that changes. Therefore, according to the third embodiment, when a surge voltage is applied from the direction of arrow A2 outside the package, the electric resistance of the resistance layer 14a decreases, and this surge voltage is guided to the ground GND, and Internal electronic circuits can be protected.

FIG. 10 is a perspective view of a fourth embodiment of the present invention.

In FIG. 10, a wafer chip 4 and a sheet 6 sealed in a package are electrically connected to the outside of the package by a total of four lead frames 1a to 1d of the present invention shown in FIG. Connected.

The lead frames 1a and 1b have the same portions as those of the first embodiment of the present invention described above except that portions indicated by reference symbols Ba and Bb have been removed by laser light. The equivalent circuit of these lead frames 1a and 1b is as shown in FIG. 11 or FIG. 12, respectively. 11 and FIG.
a, a ', b, b' are the same as those of FIG.

The length L1 of the lead frame 1a shown in FIG. 2 is shorter than that of the lead frame 1b. Therefore, in FIGS. 11 and 12, the resistance value of the resistance element R3 is smaller than the resistance value of the resistance element R4.

Accordingly, the input / output portion of the wafer chip 4 connected by the lead frame 1a can effectively perform electrostatic protection while reducing signal delay due to the electric resistance of the resistance element of the protection element. it can.

On the other hand, since the input / output portion of the wafer chip 4 connected by the lead frame 1b has a margin for signal delay, the electric resistance of the resistance element used as the protection element is increased to increase the electrostatic resistance. The protection effect is further improved.

The lead frame 1c shown in FIG.
5 are removed by the laser beam, and FIG.
7 is the same as the second embodiment of the present invention described above with reference to FIG. That is, the first conductive layer 11 and the resistance layer 14 and the second conductive layer 11 connected to the ground GND with the insulating layer 16 interposed therebetween.
A capacitance element (capacitance element C4 in FIG. 13) having the conductive layer 12 as a counter electrode is formed to protect against a surge voltage. The equivalent circuit of the lead frame 1c is as shown in FIG.

FIG. 14 is an equivalent circuit for the lead frame 1d. In FIGS. 13 and 14, reference numerals c, c ', d, d', and e are the same as those in FIG.

[0065]

As described above, according to the present invention, in a lead frame provided for electrically connecting an electronic component encapsulated in a package to the outside of the package, the electronic component applied from the outside of the package is provided. It is possible to protect the electronic components in the package from surge voltage, to increase the resistance value relatively while avoiding a decrease in withstand voltage, and to reduce the resistance value of the resistance element configured for protection. An excellent effect of being able to provide a lead frame with a protection element that can be different for each lead frame can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the gist of the present invention.

FIG. 2 is a side view of the first embodiment of the present invention.

FIG. 3 is a top view of the first embodiment.

FIG. 4 is an equivalent circuit diagram of the first embodiment.

FIG. 5 is a side view of a second embodiment of the present invention.

FIG. 6 is a bottom view of the second embodiment.

FIG. 7 is an equivalent circuit diagram of the second embodiment.

FIG. 8 is an equivalent circuit diagram of a modification of the second embodiment.

FIG. 9 is a side view of a third embodiment of the present invention.

FIG. 10 is a perspective view of a fourth embodiment of the present invention.

FIG. 11 is an equivalent circuit of a lead frame 1a used in the fourth embodiment.

FIG. 12 is an equivalent circuit of a lead frame 1b used in the fourth embodiment.

FIG. 13 is an equivalent circuit of a lead frame 1c used in the fourth embodiment.

FIG. 14 is an equivalent circuit of a lead frame 1d used in the fourth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Lead frame, 2 ... Wire, 4 ... Wafer chip, 6 ... Sheet, 11 ... 1st conductive layer, 11a-11g ... Divided conductive layer part of 1st conductive layer, 12 ... 2nd conductive layer, 12a, 12b: divided conductive layer portion of the second conductive layer, 14: resistive layer, 16: insulating layer, R1 to R4: resistive element, C1 to C4: capacitive element, GND: ground (ground).

Claims (3)

(57) [Claims] In a lead frame provided for electrically connecting an electronic component sealed in a package to the outside of the package, a first conductive layer made of a material having a relatively low electrical resistance and a resistance element are formed. used for writing, organic and resistive layer by a material having a predetermined electrical resistance, and the electric resistance is sufficiently large insulating layer, a second conductive layer relatively electrical resistance due to low material has a stacked multilayer structure in this order And the first guide
An electric layer or the resistance layer and the second conductive layer
A lead frame with a protection element, wherein a capacitance element as a pole is formed and a protection element is formed. 2. The method of claim 1, by using the resistor layer, is inserted into the electrical connection by the lead frame in series, used for the protective element
A lead frame with a protection element characterized by incorporating a resistance element. 3. The lead frame with a protection element according to claim 1, wherein the material of the resistance layer is a material whose electric resistance changes according to an applied voltage.