JP2004281705A - Signal transmitting circuit and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To protect a circuit element from electrostatic breakdown and, at the same time, to transmit high-speed signals in a semiconductor circuit. <P>SOLUTION: The semiconductor circuit contains an input terminal 50, a protective circuit 56 which discharges a voltage of a prescribed value or higher when the voltage is impressed, and a cell 10 containing the circuit element. The protective circuit 56 and cell 10 are connected to the input terminal 50 in branched states. On wiring 18c connected with the cell 10, a resistor R<SB>2</SB>is disposed so that the resistance value of the wiring 18c may become higher than that of the wiring 18b connected with the protective circuit 56. In addition, a section 54 to be cut is formed on the wiring 18b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a signal transmission circuit and a method for manufacturing the signal transmission circuit. The present invention particularly relates to a signal transmission circuit that prevents electrostatic breakdown of a circuit element during a predetermined manufacturing process, and that can transmit a high-speed signal to the circuit element after the manufacturing process is completed, and a method of manufacturing the same. .
[0002]
[Prior art]
2. Description of the Related Art A semiconductor circuit is provided with a protection circuit for suppressing a high-voltage pulse that enters a circuit element due to static electricity in order to prevent electrostatic destruction during mounting and transport. For example, Patent Literature 1 discloses a semiconductor circuit including a transistor-type protection circuit and a series resistor as a countermeasure against static electricity. Thus, a signal from the outside is transmitted to the internal circuit via the protection circuit, so that electrostatic breakdown can be prevented.
[0003]
By the way, Patent Document 2 discloses a technique in which a special circuit which is used only in a manufacturing process such as a redundant circuit or a test process and becomes unnecessary after a product is completed is cut with a fuse. Here, the input terminal is connected to a fuse via an input protection circuit, and further connected to a circuit to be separated via a fuse. By cutting the fuse, the circuit to be separated can be separated from the input terminal.
[0004]
[Patent Document 1]
JP-A-5-102411 [Patent Document 2]
JP-A-7-86516 [0005]
[Problems to be solved by the invention]
However, in the conventional semiconductor circuit having the protection circuit described in Patent Document 1, since a signal is transmitted to the internal circuit through the protection circuit even after the semiconductor circuit is manufactured, a high-speed signal is input. In such a case, there is a problem that the speed of the signal input to the internal circuit is reduced. For example, in Patent Document 2 described above, the input protection circuit is provided between the input terminal and the fuse, and the input protection circuit is connected to the input terminal even after disconnecting the circuit to be separated by cutting the fuse. It has a configuration.
[0006]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique for preventing electrostatic breakdown without lowering a signal speed input to a circuit element.
[0007]
[Means for Solving the Problems]
According to the present invention, a signal transmission circuit for transmitting a signal to a circuit element is provided. The signal transmission circuit has an input terminal, a protection circuit that discharges the voltage when a voltage equal to or higher than a predetermined value is applied, a first path that connects the input terminal and the circuit element via the protection circuit, A second path connecting the input terminal and the circuit element without passing through the protection circuit, and the second path electrically disconnects the input terminal and the circuit element by cutting the first path. Configured to connect.
[0008]
With this configuration, the input terminal and the circuit element are electrically connected via the first path until the first path is disconnected, so that the circuit element can be protected by the protection circuit. On the other hand, by cutting the first path, the input terminal and the circuit element are electrically connected via the second path, so that the high-speed signal input to the input terminal is transmitted to the circuit element without delay. be able to.
[0009]
Here, the connection via the protection circuit means that the input signal is connected so that the function of the protection circuit is performed. In the first path, the protection circuit may be provided on a wiring connecting the input terminal and the circuit element, or may be provided on a wiring branched from the wiring connecting the input terminal and the circuit element. Good.
[0010]
In the signal transmission circuit of the present invention, a resistor may be provided on the second path, and the resistance is configured such that a resistance value in the second path is higher than a resistance value in the first path. May be.
[0011]
Thus, until the first path is disconnected, the signal input to the input terminal is transmitted to the circuit element via the first path. Therefore, when a high voltage is applied to the input terminal, the voltage is discharged in the protection circuit, so that the circuit element can be protected. For example, a fuse circuit can be provided in the first path, and the fuse circuit can be cut by flowing a large current through the fuse circuit. In addition, a heating element may be provided in the vicinity of the fuse circuit, and the first path may be disconnected by causing the heating element to generate heat. Further, the first path may be a wiring made of a material that can be cut by an acid or an alkali, and the wiring may be cut by dropping an acid or an alkali. Further, the first path can be cut by irradiating a laser beam.
[0012]
According to the present invention, a signal transmission circuit for transmitting a signal to a circuit element is provided. The signal transmission circuit includes an input terminal, a protection circuit that discharges the voltage when a voltage equal to or higher than a predetermined value is applied, and a connection unit that branches the protection circuit and the circuit element to connect to the input terminal. .
[0013]
By doing so, the input terminal and the circuit element can be connected even if the protection circuit is disconnected.
[0014]
In the signal transmission circuit of the present invention, the connection means may include a first branch wiring connecting the input terminal and the protection circuit, and a second branch wiring connecting the input terminal and the circuit element, A resistor may be provided on the second branch line, and the resistor may be configured such that a resistance value of the second branch line is higher than a resistance value of the first branch line.
[0015]
With this configuration, the signal input from the input terminal is preferentially transmitted to the first branch wiring, and is transmitted to the second branch wiring after passing through the protection circuit, so that a high voltage is applied. In this case, the circuit element can be protected by the protection circuit. After the process requiring the protection circuit is completed, by cutting the first branch wiring, the input terminal and the circuit element can be connected without passing through the protection circuit, and a high-speed signal is input from the input terminal. In this case, it can be transmitted to the circuit element without delay.
[0016]
The signal transmission circuit of the present invention may further include an insulating film covering the first branch wiring, and the insulating film may have an opening for exposing the first branch wiring.
[0017]
The first branch wiring can be cut by, for example, irradiating a laser beam, applying pressure, or dropping an acid to the opening configured as described above.
[0018]
In the signal transmission circuit of the present invention, the first branch wiring may be made of any of aluminum, copper, silver, and gold, or an alloy thereof, and the first branch wiring may be obtained by dropping an acid into the opening. May be cut. When the first branch wiring is made of aluminum, it can be cut by dropping an alkaline solution into the opening.
[0019]
According to the present invention, there is provided a method of manufacturing a signal transmission circuit for transmitting a signal to a circuit element formed on a substrate. The method for manufacturing a signal transmission circuit includes a step of forming a protection circuit that discharges a voltage equal to or higher than a predetermined value on a substrate; a step of forming an input terminal on the substrate; Forming a connection means including a first branch wiring for connecting the input terminal and the protection circuit, and a second branch wiring for connecting the input terminal and the circuit element; Forming an insulating film covering the branch wiring, and forming an opening in the insulating film so that a part of the first branch wiring is exposed.
[0020]
The first branch wiring can be cut by, for example, irradiating a laser beam, applying pressure, or dropping an acid to the opening configured as described above.
[0021]
In the method for manufacturing a signal transmission circuit according to the present invention, the first branch wiring can be made of any of aluminum, copper, silver, and gold, or an alloy thereof, and the first branch wiring is exposed to the first branch wiring from the opening. By dropping the acid, the first branch wiring can be cut. When the first branch wiring is made of gold, it can be cut by dropping aqua regia into the opening. When the first branch wiring is made of aluminum, it can be cut by dropping an alkaline solution into the opening.
[0022]
According to the present invention, a circuit element, an input terminal, a protection circuit that discharges the voltage when a voltage equal to or more than a predetermined value is applied, and a first circuit that connects the input terminal and the circuit element via the protection circuit Path, and a second path for connecting the input terminal and the circuit element without passing through the protection circuit, the second path, the input terminal and the circuit element by cutting the first path Are provided so as to be electrically connected to each other.
[0023]
According to the present invention, a circuit element, an input terminal, a protection circuit that discharges the voltage when a voltage equal to or higher than a predetermined value is applied, and a connection unit that branches the protection circuit and the circuit element to connect to the input terminal And a semiconductor circuit comprising:
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a diagram conceptually showing a semiconductor circuit according to an embodiment of the present invention.
In the present embodiment, the semiconductor circuit includes the cell section 10, the input terminal 50, the protection circuit 56, and the wiring 18 for electrically connecting these. This semiconductor circuit includes a first path connecting the input terminal 50 and the cell unit 10 via the protection circuit 56, and a second path connecting the input terminal 50 and the cell unit 10 without passing through the protection circuit 56. And the route. The semiconductor circuit further includes a connection unit 53 that selects whether the signal from the input terminal 50 is input to the cell unit 10 through the first path or the second path.
[0025]
The cell unit 10 is provided with a circuit element such as a semiconductor element such as a transistor, a diode, and an IC chip, or a passive element such as a chip capacitor and a chip resistor. The protection circuit 56 discharges a high voltage when an excessive voltage or a high voltage due to static electricity is applied from the input terminal 50. This prevents the cell unit 10 from being electrostatically damaged. The connection unit 53 receives a signal through the first path during a predetermined manufacturing process of the semiconductor circuit, for example, in a process in which electrostatic breakdown easily occurs, such as a pre-process, transport, dicing, and mounting work on a lead frame. And in a subsequent step, a signal is selected to be input through the second path. As a result, since the input terminal 50 and the cell unit 10 are connected without passing through the protection circuit after the end of the previous process, the signal input to the input terminal 50 can be transmitted to the cell unit 10 without delay.
[0026]
FIG. 2 is a schematic diagram specifically showing the semiconductor circuit in the present embodiment. Here, the semiconductor circuit includes a wiring 18a connected to the input terminal 50, a wiring 18b connected to the protection circuit 56, and a wiring 18c connected to the cell unit 10. Connecting means 53 includes a first resistor R ₁ which is formed on the wiring 18a, and the second resistor R ₂ which is formed on the wiring 18c, and the cutting portion 54 formed on the wiring 18b. Here the resistance of the cutting portions 54 and R _3. The cut portion 54 is, for example, a fuse circuit. An internal protection circuit 52 is provided on the wiring 18c. Like the protection circuit 56, the internal protection circuit 52 has a function of protecting the cell unit 10, but has a smaller capacity than the protection circuit 56, and is of such a degree as not to be affected by signal delay.
[0027]
In the semiconductor circuit of this embodiment, the resistance value of the resistor R ₃ of the cutting portion 54 is configured to be lower than the second resistance value of the resistance R ₂ of. With this configuration, when both the wiring 18b and the wiring 18c are connected to the wiring 18a, a signal input from the input terminal 50 is transmitted to the cell unit 10 via the protection circuit 56. Therefore, when an excessive voltage or a voltage due to the influence of static electricity is applied to the input terminal 50, these voltages are discharged in the protection circuit 56. Thereby, the cell unit 10 can be protected from excessive voltage and static electricity.
[0028]
On the other hand, by cutting the cut portion 54, the signal input to the input terminal 50 can be transmitted to the cell unit 10 without passing through the protection circuit 56.
[0029]
Next, a method of cutting the cut portion 54 will be described. The portion to be cut 54 can be cut by various methods. For example, a portion of the wiring 18b may be formed to be thin, and the cutting may be performed by applying a large current to the wiring 18b or applying heat. In addition, the wiring 18b can be cut by dropping an acid or alkali, irradiating a laser beam, applying pressure, or the like.
[0030]
FIG. 3 is a diagram illustrating an example of the configuration of the cut portion 54. Here, the cut portion 54 is a thin line formed by thinning a part of the wiring 18b. The semiconductor circuit further has an input terminal 58 connected to the cut section 54. It is preferable that the input terminal 58 be configured to be covered with an insulating film. In this way, even if a voltage is applied from the input terminal 50, a large current does not flow through the wiring 18b, and it is possible to prevent the cut portion 54 from being cut during a predetermined semiconductor circuit manufacturing process. . After the predetermined manufacturing process is completed, a probe is stabbed in an insulating film covering the input terminal 58, the probe is electrically connected to the input terminal 58, and a large current is caused to flow from the input terminal 58 to the wiring 18b. In this case, the wiring 18b can be cut. Here, the resistance value of the first resistor R ₁ is configured to be lower than the resistance value of the second resistor R _2. By doing so, a large current flowing through the wiring 18b is guided to the input terminal 50 via the wiring 18a without flowing to the wiring 18c. Thus, a large current can be applied to the wiring 18b to cut the cut-off portion 54 while protecting the cell portion 10. By cutting the portion to be cut 54, a signal input to the input terminal 50 can be transmitted to the cell unit 10 without passing through the protection circuit 56 in a subsequent process, and a high-speed signal is transmitted to the cell unit 10 without delay. can do.
[0031]
FIG. 4 is a diagram showing another example of the configuration of the cut portion 54. Here, the cut portion 54 is also a thin line formed by thinning a part of the wiring 18b. The semiconductor circuit includes a heating means 60 provided near the thin line portion of the wiring 18b. The heat generating means may be a resistor that generates heat when a voltage is applied. Further, the semiconductor circuit includes an input terminal 58 for applying a voltage to the heating means 60. With this configuration, by applying a voltage to the input terminal 58, the heat generating means 60 generates heat, and the cut target portion 54 can be cut.
[0032]
FIG. 5 is a diagram illustrating another example of the semiconductor circuit of the present embodiment. FIG. 5A is a top view of the semiconductor circuit. Here, the protection circuit 56 and the cell unit 10 are covered with the insulating layer 22, and the description is omitted. An opening 60 for exposing the wiring 18b is formed in the insulating layer 22.
[0033]
FIG. 4B is a sectional view taken along line AA ′ of FIG. The semiconductor circuit has the substrate 20, and the cell unit 10 and the protection circuit 56 are formed on the substrate 20. The cell section 10, the protection circuit 56, the resistor R ₂ , the wiring 18a, the wiring 18b, and the wiring 18c are covered with the insulating layer 22. The wirings 18a to 18c are made of a relatively low-resistance metal such as aluminum, copper, silver, or gold, or an alloy thereof. The opening 60 can be formed by, for example, a laser or the like. In the semiconductor circuit thus configured, the wiring 18b can be cut at the cut portion 54 by dropping acid into the opening 60. The wiring 18b can be cut by irradiating a laser beam from the opening 60.
[0034]
According to the semiconductor circuit of the present embodiment, before cutting the cut target portion 54, various signals are transmitted to the cell portion 10 via the protection circuit 56, so that an excessive voltage or a high voltage due to static electricity is applied. In this case, the cell section 10 can be protected from electrostatic breakdown. On the other hand, after cutting the cut portion 54, various signals are transmitted to the cell unit 10 without passing through the protection circuit 56, so that a high-speed signal can be transmitted to the cell unit 10 without delay.
[0035]
Such a circuit is not particularly limited, but is preferably used, for example, for connecting different circuit elements on the same interposer. This is because no circuit element on the same interposer has a potential difference, so there is no possibility of applying an excessive voltage.
[0036]
【The invention's effect】
As described above, according to the present invention, it is possible to protect a circuit element from electrostatic destruction in a manufacturing process of a semiconductor circuit and to transmit a high-speed signal to the circuit element after a predetermined step is completed.
[Brief description of the drawings]
FIG. 1 is a diagram conceptually showing a semiconductor circuit according to an embodiment of the present invention.
FIG. 2 is a schematic diagram specifically showing a semiconductor circuit according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating an example of a configuration of a cut portion illustrated in FIG. 2;
FIG. 4 is a diagram showing another example of the configuration of the section to be cut shown in FIG. 2;
FIG. 5 is a diagram showing another example of the configuration of the section to be cut shown in FIG. 2;
[Explanation of symbols]
Reference Signs List 10 cell portion, 18, 18a, 18b, 18c wiring, 20 substrate, 22 insulating layer, 50 input terminal, 52 internal protection circuit, 53 connection means, 54 cut portion, 56 protection circuit, 58 input terminal, 60 opening.

Claims (7)

A signal transmission circuit for transmitting a signal to a circuit element,
An input terminal,
A protection circuit that discharges the voltage when a voltage equal to or higher than a predetermined value is applied,
A first path connecting the input terminal and the circuit element via the protection circuit,
A second path connecting the input terminal and the circuit element without passing through the protection circuit;
Including
The signal transmission circuit, wherein the second path is configured to electrically connect the input terminal and the circuit element by cutting the first path. The signal transmission circuit according to claim 1,
A signal is provided on the second path, wherein the resistance is configured such that a resistance value of the second path is higher than a resistance value of the first path. circuit. A signal transmission circuit for transmitting a signal to a circuit element,
An input terminal,
A protection circuit that discharges the voltage when a voltage equal to or higher than a predetermined value is applied,
Connection means for branching the protection circuit and the circuit element and connecting to the input terminal;
A signal transmission circuit comprising: The signal transmission circuit according to claim 3,
A first branch wiring that connects the input terminal and the protection circuit,
Including a second branch wiring that connects the input terminal and the circuit element,
A resistor is provided on the second branch line, and the resistor is configured such that a resistance value of the second branch line is higher than a resistance value of the first branch line. Signal transmission circuit. The signal transmission circuit according to claim 4,
Further comprising an insulating film covering the first branch wiring,
A signal transmission circuit, wherein an opening for exposing the first branch wiring is formed in the insulating film. A method for manufacturing a signal transmission circuit for transmitting a signal to a circuit element formed on a substrate,
Forming a protection circuit that discharges the voltage when a voltage equal to or higher than a predetermined value is applied to the substrate,
Forming an input terminal on the substrate;
A step of forming a connection means on the substrate, the first branch line connecting the input terminal and the protection circuit, and the second branch line connecting the input terminal and the circuit element; ,
Forming an insulating film covering the first branch wiring on the substrate;
Forming an opening in the insulating film so that a part of the first branch wiring is exposed;
A method for manufacturing a signal transmission circuit, comprising: The method for manufacturing a signal transmission circuit according to claim 6,
The first branch wiring is made of aluminum, copper, silver, gold, or an alloy thereof, and the first branch wiring is cut by dropping an acid on the first branch wiring exposed from the opening. A method of manufacturing a signal transmission circuit.

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