JP4401092B2 - Method for manufacturing signal transmission circuit and method for manufacturing semiconductor circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a signal transmission circuit, a method for manufacturing a signal transmission circuit, and a method for manufacturing a semiconductor circuit. In particular, the present invention prevents the electrostatic breakdown of a circuit element during a predetermined manufacturing process, and manufactures a signal transmission circuit and a signal transmission circuit capable of transmitting a high-speed signal to the circuit element after the manufacturing process is completed. The present invention relates to a method and a method for manufacturing a semiconductor circuit.
[0002]
[Prior art]
The semiconductor circuit is provided with a protection circuit for suppressing high voltage pulses that enter the circuit element due to static electricity in order to prevent electrostatic breakdown during mounting or transportation. For example, Patent Document 1 discloses a semiconductor circuit including a transistor-type protection circuit and a series resistor as a countermeasure against static electricity. As a result, an external signal is transmitted to the internal circuit via the protection circuit, so that electrostatic breakdown can be prevented.
[0003]
[Patent Document 1]
JP-A-5-102411 [0004]
[Problems to be solved by the invention]
However, in a semiconductor circuit having a conventional protection circuit, a signal is transmitted to the internal circuit via the protection circuit even after the semiconductor circuit is manufactured. There is a problem that the signal speed is reduced.
[0005]
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 reducing the speed of a signal input to a semiconductor circuit.
[0006]
[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 includes a protection circuit that discharges the voltage when a voltage of a predetermined value or more is applied, a first input terminal that is electrically connected to the circuit element via the protection circuit, and a protection circuit. A second input terminal electrically connected to the circuit element without passing through, and an insulating film covering at least the second input terminal. Here, an opening for exposing the second input terminal is formed in the insulating film.
[0007]
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.
[0008]
In this way, for example, when circuit elements formed on different substrates are connected to each other, when there is a possibility of electrostatic breakdown, a signal can be input from the first input terminal, and a high-speed signal can be input. When it is not desired to delay the signal as in the case of inputting the signal, the signal can be input from the second input terminal.
[0009]
The opening that exposes the second input terminal is formed after a process in which electrostatic breakdown is likely to occur, such as so-called pre-process, transport, dicing, and mounting to a lead frame in a predetermined manufacturing process of a semiconductor circuit. The As a result, in these steps, the circuit element can be protected, and after the opening is formed and the second terminal is exposed, a signal can be input from the second terminal. Can be transmitted to the circuit element without delay.
[0010]
In the signal transmission circuit of the present invention, the second input terminal may be formed wider than the opening area of the opening. Here, the opening can be formed by a laser such as a CO ₂ laser. The second input terminal is made of a relatively low resistance metal such as copper, silver, or aluminum. By forming the second input terminal wider than the opening area of the opening, when the opening is formed with a laser, the absorptance with respect to a metal such as copper, silver, or aluminum constituting the second input terminal By selecting a low wavelength, the input terminal itself acts as a mask and reflects the laser, so that the underlying layer can be protected from the laser. The opening can also be formed by dry etching using a lithography technique, a drill, or the like. When the opening is formed by dry etching, the input terminal itself serves as a mask by appropriately selecting and setting the gas and pressure to be used, so that the underlying layer can be protected.
[0011]
According to the present invention, a signal transmission circuit for transmitting a signal to a circuit element is provided. The signal transmission circuit includes a protection circuit that discharges the voltage when a voltage of a predetermined value or more is applied, a first input terminal that is electrically connected to the circuit element via the protection circuit, and a protection circuit. A second input terminal electrically connected to the circuit element without passing through, and an insulating film covering the first input terminal and the second input terminal. Here, the insulating film is formed with an opening through which the first input terminal is exposed, and the second input terminal includes an electrode pad formed wider than the opening area of the opening.
[0012]
In this way, by forming an opening through which the second input terminal is exposed after the predetermined manufacturing process is completed, the circuit element is prevented from being input from the second input terminal until then. In addition to protection, after the opening is formed, a signal can be input from the second input terminal to enable high-speed signal transmission.
[0013]
According to the present invention, a method of manufacturing a signal transmission circuit that transmits a signal to a circuit element is provided. In this manufacturing method, on the substrate, when a voltage of a predetermined value or more is applied, a protection circuit that discharges the voltage, a first input terminal electrically connected to the circuit element via the protection circuit, Forming a second input terminal electrically connected to the circuit element without going through the protection circuit, forming an insulating film covering the second input terminal, and forming a second input terminal on the insulating film. Forming an opening through which the input terminal is exposed.
[0014]
In this way, the circuit element is protected by preventing the signal from being input from the second input terminal until the opening where the second input terminal is exposed, and the signal is not transmitted after the opening is formed. A high-speed signal can be transmitted by inputting from the second input terminal.
[0015]
In the method for manufacturing a signal transmission circuit of the present invention, the opening can be formed by irradiating laser light.
[0016]
In the signal transmission circuit manufacturing method of the present invention, the second input terminal may be formed so as to include an electrode pad, and the opening is formed so that the opening area of the opening is smaller than the area of the electrode pad. can do.
[0017]
In this way, when the opening is formed with a laser, the electrode pad serves as a mask to reflect the laser, so that the underlying layer can be protected from the laser. Thereby, an opening part can be formed favorable.
[0018]
According to the present invention, there is provided a signal transmission method for transmitting a signal to a circuit element formed on a substrate, wherein a signal from another circuit element formed on a substrate different from the substrate is supplied with a voltage equal to or higher than a predetermined value. When a signal is applied, a signal is input to the circuit element via a protection circuit that discharges the voltage, and a signal from another circuit element formed on the same substrate is transmitted without passing through the protection circuit. And a step of inputting to the device.
[0019]
According to the present invention, on a substrate, a circuit element, a protection circuit that discharges the voltage when a voltage equal to or higher than a predetermined value is applied, and a first circuit electrically connected to the circuit element via the protection circuit Forming a first input terminal and a second input terminal electrically connected to the circuit element without going through the protection circuit, forming an insulating film covering the second input terminal, and a circuit There is provided a method for manufacturing a semiconductor circuit, comprising: a step of separating an element from another region; and a step of forming an opening exposing the second input terminal in the insulating film after the step of separating. Is done. Here, the step of separating is, for example, a dicing step. In this way, the circuit element can be protected by preventing the signal from being input from the second input terminal in the process where electrostatic breakdown is likely to occur, and the signal from the second input terminal in the subsequent process. Can be input to enable high-speed signal transmission.
[0020]
According to the present invention, a circuit element, a protection circuit that discharges the voltage when a voltage equal to or higher than a predetermined value is applied, and a first input terminal electrically connected to the circuit element via the protection circuit, A second input terminal electrically connected to the circuit element without going through the protection circuit, and an insulating film covering at least the second input terminal, wherein the second input terminal is exposed to the insulating film There is provided a semiconductor circuit characterized in that an opening is formed.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic diagram showing a semiconductor circuit according to an embodiment of the present invention.
In the present embodiment, the semiconductor circuit includes a cell portion 10, a protection circuit 12, a first pad electrode 14, a second pad electrode 16, and a wiring 18 that electrically connects them. The first pad electrode 14 and the second pad electrode 16 can also be formed integrally with the wiring 18. The cell unit 10 is provided with circuit elements such as semiconductor elements such as transistors, diodes and IC chips, or passive elements such as chip capacitors and chip resistors. The protection circuit 12 prevents the cell unit 10 from being destroyed by excessive voltage or static electricity applied from the outside.
[0022]
A signal input from the first pad electrode 14 is transmitted to the cell unit 10 via the protection circuit 12. A signal input from the second pad electrode 16 is transmitted to the cell unit 10 without passing through the protection circuit 12.
[0023]
FIG. 2 is a process cross-sectional view showing the manufacturing process of the semiconductor circuit in the embodiment of the present invention.
FIG. 2A is a cross-sectional view showing the configuration of the semiconductor circuit at the stage where the so-called pre-process of the semiconductor manufacturing process is completed. At this stage, the semiconductor circuit includes a substrate 20, an insulating layer 22, a wiring support member 17, and a wiring support member 19 in addition to the configuration shown in FIG. 1. The protection circuit 12 and the cell unit 10 are installed on the substrate 20, and an insulating layer 22 is formed so as to cover the cell unit 10 and the protection circuit 12. In the insulating layer 22, a first opening 15 is formed above the first pad electrode 14. At this time, the second pad electrode 16 is configured not to be exposed to the outside.
[0024]
In the semiconductor circuit manufacturing process (pre-process), various signals are input to the first pad electrode 14. Since the signal input from the first pad electrode 14 is transmitted to the cell unit 10 through the protection circuit 12, even if a voltage due to the influence of excessive voltage or static electricity is applied to the first pad electrode 14, These voltages are discharged in the protection circuit 12. Thereby, the cell part 10 can be protected from excessive voltage and static electricity.
[0025]
Although the first pad electrode 14 and the second pad electrode 16 can be formed integrally with the wiring 18, they are formed wider than the wiring 18 as shown in FIG. 1. The second pad electrode 16 is formed in a size of 10 um ² or more, for example. The first pad electrode 14, the second pad electrode 16, and the wiring 18 are preferably made of a material having a relatively low resistance such as copper, silver, or aluminum. When the wiring support member 17 and the wiring support member 19 are subjected to pressure or ultrasonic waves to form bumps or wires on the first pad electrode 14 and the second pad electrode 16 in a later process, The pad electrode 14 and the second pad electrode 16 are respectively supported so as not to be deformed. The semiconductor circuit may be configured without the wiring support member 17 and the wiring support member 19.
[0026]
After the previous process is completed in such a state, the semiconductor circuit is transferred, diced, mounted on a lead frame, and the like. In the present embodiment, the semiconductor circuit is configured as shown in FIG. 1A until these steps are completed. In this way, since a signal is input to the cell unit 10 from the outside via the protection circuit 12, electrostatic breakdown during transportation, dicing, and mounting can be prevented.
[0027]
After the conveyance, dicing, and mounting operations are completed, a second opening 24 is formed on the second pad electrode 16 as shown in FIG. The second opening 24 can be formed using, for example, a CO ₂ laser. When the second opening 24 is formed with a CO ₂ laser, a wavelength having a low absorptance with respect to a metal such as copper, silver, or aluminum constituting the second pad electrode 16 is selected. Since the pad electrode 16 serves as a mask and reflects the CO ₂ laser, the underlying layer can be protected from the laser. Thereby, the second opening 24 can be suitably formed without removing even the lower layer of the second pad electrode 16.
[0028]
Subsequently, as shown in FIG. 2C, bumps 26 are formed on the second pad electrode 16 and electrically connected to other circuit elements via wires 28. The bump 26 can be made of, for example, gold or solder.
[0029]
In the present embodiment, after the second opening 24 is formed, various signals are input to the second pad electrode 16. As a result, various signals are transmitted to the cell unit 10 without going through the protection circuit 12, so that the input signals can be transmitted at high speed. Further, in the present embodiment, the second opening 24 is formed so that the second pad electrode 16 is externally provided in a process in which electrostatic breakdown is likely to occur such as pre-process, conveyance, dicing, and mounting work on a lead frame. Therefore, the cell portion 10 can be protected by the protection circuit 12, and electrostatic breakdown can be prevented.
[0030]
FIG. 3 is a diagram illustrating another example of a connection portion between the semiconductor circuit illustrated in FIG. 2C and other circuit elements. The second pad electrode 16 can be connected to the bumps 30 of other circuit elements 36 via the bumps 26 and the solder balls 29 provided on the second pad electrode 16 without using the wires 28. . Alternatively, the bump 26 and the bump 30 can be directly connected.
[0031]
FIG. 4 is a diagram illustrating an example of the internal configuration of the protection circuit 12. Protection circuit 12 includes a diode 32 and a diode 34 between the power supply potential and the ground potential. The diode 32 and the diode 34 are PN junction diodes. The cathode of the diode 32 is fixed to the power supply potential VDD, and the anode is connected to the first pad electrode 14 and the second pad electrode 16 via the wiring 18. The anode of the diode 32 is also connected to the cathode of the diode 34. The anode of the diode 34 is fixed to the ground potential GND, and the cathode is connected to the first pad electrode 14 and the second pad electrode 16 via the wiring 18.
[0032]
In the protection circuit 12 configured as described above, when an excessive voltage due to static electricity or the like is applied from the outside, the static electricity applied to the power supply potential VDD or the ground potential GND is discharged according to the polarity of the applied voltage. Therefore, the cell unit 10 can be protected.
[0033]
Further, as shown in FIG. 5, the first pad electrode 14 and the second pad electrode 16 can be used in parallel even after the second opening 24 is formed. Circuit elements formed on different substrates can be connected by wires 40 via bumps 38 formed on the first pad electrode 14. At this time, various signals are transmitted to the cell unit 10 via the first pad electrode 14. When connecting circuit elements formed on different substrates, there is a possibility that an excessive voltage is generated due to a potential difference between the substrates. Even in such a case, since the signal is input through the first pad electrode 14, the excess voltage is discharged in the protection circuit 12, and the cell unit 10 can be protected. On the other hand, circuit elements on the same wafer can be connected by a wire 28, and a signal is input via the second pad electrode 16. This is because the circuit elements on the same wafer do not cause a potential difference and therefore there is no fear of application of excessive voltage. As a result, only signals between circuit elements that may cause excessive voltage can be input via the protection circuit 12, and other signals can be input at high speed.
[0034]
Furthermore, the semiconductor circuit can be configured as shown in FIG. As shown in FIG. 6A, the second pad electrode 16 is not formed on the wiring 18 to which the first pad electrode 14 is connected, and is connected to a wiring 41 different from the wiring 18. can do.
[0035]
Further, as shown in FIG. 6B, the protection circuit 12 may be configured to be connected to a wiring 42 different from the wiring 18. In this case, a resistor R is provided between the first pad electrode 14 and the cell unit 10 so that a signal input from the first pad electrode 14 is transmitted to the cell unit 10 via the protection circuit 12. Be placed. The resistor R is configured such that the resistance value between the first pad electrode 14 and the cell unit 10 is higher than the resistance value between the first pad electrode 14 and the protection circuit 12. As a result, a signal input from the first pad electrode 14 is preferentially transmitted to the wiring 42, and can be transmitted to the cell unit 10 after passing through the protection circuit 12.
[0036]
Further, the semiconductor circuit may be configured as shown in FIG. Here again, the second pad electrode 16 is connected to a wiring 41 branched from the wiring 18 to which the first pad electrode 14 is connected. In this case, an inverter 44 that allows current to flow only in the direction from the protection circuit 12 to the cell unit 10 can be provided between the second pad electrode 16 and the protection circuit 12, for example. As a result, the signal input from the second pad electrode 16 does not flow in the direction of the protection circuit 12 but is directly transmitted to the cell unit 10.
[0037]
Moreover, in the above embodiment, the example which forms the 2nd opening part 24 using a laser beam was demonstrated, but the 2nd opening part 24 uses the dry etching using a lithography technique, a drill, etc. It can also be formed. When the second opening 24 is formed by dry etching, it is preferable to appropriately select and set the gas and pressure to be used. Thereby, since the input terminal itself becomes a mask, the layer below it can be protected.
[0038]
【The invention's effect】
As described above, according to the present invention, a circuit element can be protected from electrostatic breakdown in a semiconductor circuit manufacturing process, and a high-speed signal can be transmitted to the circuit element after the completion of a predetermined process.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a semiconductor circuit in an embodiment of the present invention.
FIG. 2 is a process cross-sectional view illustrating a manufacturing process of a semiconductor circuit in an embodiment of the present invention.
3 is a diagram showing another example of a connection portion between the semiconductor circuit shown in FIG. 2 and other circuit elements.
FIG. 4 is a diagram illustrating an example of an internal configuration of a protection circuit.
FIG. 5 is a cross-sectional view showing a semiconductor circuit in an embodiment of the present invention.
6 is a schematic view showing another example of the semiconductor circuit shown in FIG. 1. FIG.
7 is a schematic view showing another example of the semiconductor circuit shown in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 cell part, 12 protection circuit, 14 1st pad electrode, 15 1st opening part, 16 2nd pad electrode, 17 wiring support member, 18 wiring, 19 wiring support member, 20 board | substrate, 22 insulating layer, 24 Second opening, 26 bumps, 28 wires, 29 solder balls, 30 bumps, 32 diodes, 34 diodes, 36 other circuit elements, 38 bumps, 40 wires, 41 wires, 42 wires, 44 inverters, R resistors.

Claims (4)

A method of manufacturing a signal transmission circuit for transmitting a signal to a circuit element,
A protection circuit that discharges the voltage when a voltage of a predetermined value or more is applied to the substrate, a first input terminal that is electrically connected to the circuit element via the protection circuit, and the protection circuit a first step of forming a second input terminal electrically connected to said circuit element without passing through the,
A second step of forming an insulating film covering the second input terminal;
After the second step, a third step of separating the region including the protection circuit, the first input terminal, and the second input terminal from other regions;
After the third step, a fourth step of forming an opening through which the second input terminal is exposed in the insulating film;
A method of manufacturing a signal transmission circuit comprising: In the manufacturing method of the signal transmission circuit according to claim 1 ,
The second input terminal is formed to include an electrode pad,
A method of manufacturing a signal transmission circuit, wherein the opening is formed so that an opening area of the opening is narrower than an area of the electrode pad. On the substrate, a circuit element, a protection circuit that discharges the voltage when a voltage of a predetermined value or more is applied, and a first input terminal electrically connected to the circuit element via the protection circuit A first step of forming a second input terminal electrically connected to the circuit element without going through the protection circuit;
A second step of forming an insulating film covering the second input terminal;
After the second step, a third step of separating the region including the circuit element , the protection circuit, the first input terminal, and the second input terminal from other regions;
After the third step, a fourth step of forming an opening through which the second input terminal is exposed in the insulating film;
A method for manufacturing a semiconductor circuit, comprising: In the manufacturing method of the semiconductor circuit according to claim 3,
A method of manufacturing a semiconductor circuit, further comprising a fifth step of mounting a substrate having the separated region on a lead frame before the fourth step.

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