JPH07142824A - Electronic circuit device and noise eliminating device - Google Patents

Abstract

PURPOSE:To avoid the operation interruption or malfunction of a circuit such as a hybrid integrated circuit due to the breakdown of a protective device due to the applied high voltage when the circuit is protected. CONSTITUTION:One (8) of discharge electrodes 8 and 9 is provided between an electrode terminal 6 and a conducting path 4 and the other electrode 9 is provided between a GND terminal 7 and a GND conducting path 5. The discharge electrodes 8 and 9 are so provided as to face each other with a predetermined gap between them and a noise voltage is grounded by a spark between the electrodes 8 and 9 to prevent the noise from entering the circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit device having a noise eliminator, and in particular, the noise eliminator can be used in common with a process of forming wirings or the like provided on a substrate and is simple. It is related to a structure that has a reproducible structure.

[0002]

2. Description of the Related Art Generally, a device having an electronic circuit mounted therein is a hybrid integrated circuit device having a semiconductor chip mounted on a ceramic, a metal substrate or a printed circuit board, a semiconductor integrated circuit device having a semiconductor element built in a Si substrate, and a transparent integrated circuit device. There is a liquid crystal display device in which a circuit is formed by utilizing a semiconductor technology or a hybrid technology (COG) on an insulating substrate such as a glass substrate or an insulating film. In these electronic circuit devices, a noise removing device is incorporated in order to prevent destruction due to static electricity existing outside, noise generated from a motor, a switch, or the like.

This noise removing device is, for example, a mounting type capacitor, a varistor, a Zener diode and a coil in a hybrid integrated circuit device, and a semiconductor integrated circuit device in which a capacitor, a diode and a Zener are formed in a Si substrate. A diode or the like, which is a diode or the like in a liquid crystal display device, which is formed together when a TFT or the like is formed, is formed from polysilicon or the like, or is mounted by a technique such as COG.

However, these are destroyed when a large surge exceeding the rating enters, and it is impossible to restore these devices unless they are replaced with new ones, for example, if they are mounted types. FIG. 6 is a partial view of a circuit that controls, for example, an engine of a car using a microcomputer. S is an engine spark plug, and L is a vehicle speed sensor, each of which is connected to a microcomputer. The circuit on the right side of the arrow X is mounted on, for example, a hybrid integrated circuit.

[0005]

Here, the capacitor C1 is used.
C2 is a noise eliminator that absorbs surges, but the input circuit of the connected microcomputer malfunctions when the capacitor C1 punctures due to a large surge. Latch it up.) And spark plug S
It becomes impossible for the microcomputer to take in the signal from.
On the other hand, since a signal is input from the vehicle speed sensor S, it is determined that the vehicle is running at a certain speed even if the engine is stopped, and the microcomputer stops as an abnormal situation.

When the noise eliminator is destroyed as described above, normal operation is not performed unless the noise eliminator is replaced with a new one, which causes inconvenience. Further, in the hybrid integrated circuit, for example, a capacitor must be mounted, and there is a problem in terms of cost and simplification of the assembly process. Unlike a capacitor, a varistor has a wide noise removal range and the destruction of the varistor is slightly reduced, but once it is destroyed, the reproducibility is lost and the assembly process such as external mounting or chip mounting is required. It was

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is electrically connected to a ground on a substrate, at least a first conductive path through which noise easily enters from the outside of the substrate. A second conductive path is provided, and between the first conductive path and the second conductive path, the first discharge electrode electrically connected to the first conductive path and the second conductive path are electrically connected. A second discharge electrode that is electrically connected is provided, and a part of the first discharge electrode and the second discharge electrode are opposed to each other and brought close to each other.

The substrate is sealed with a case,
This is solved by arranging the pair of discharge electrodes in the case closest to the external terminal and exposing at least the discharge portion.

[0009]

For example, when the discharge electrodes are exposed to the air, the air serves as a dielectric, and the distance between the discharge electrodes causes noise of a certain voltage or more to pass through between the discharge electrodes. To discharge. According to the experiment, when the distance is set to 300 μm and the thickness of the electrode is set to about 35 μm, the noise of 5 KV, 10 kV and 15 KV generated by the noise tester is discharged without any problem, and it has a function as a noise removing device. I found out. This structure can be achieved by simply bringing the electrodes close to each other. For example, in the case of a hybrid integrated circuit, it can be formed at the same time when the wiring is formed.
It is possible to save the trouble of externally attaching a chip or the like as in the past.

If the discharge part is coated with resin, the discharge voltage will be high and the discharge will not be performed well. Therefore, when passivating with a case or a resin mold,
It is necessary to expose the discharge part, and when mounting in the case, by mounting as close to the electrode terminals as possible, it is possible to perform good discharge without affecting other wirings.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The noise eliminator shown in FIGS. 1 and 2 is a ceramic, a metal substrate whose surface is subjected to insulation treatment, or a hybrid integrated circuit using a printed circuit board, a semiconductor substrate whose surface is subjected to insulation treatment, and a liquid crystal display. It can be applied to transparent glass substrates and flexible sheets used in devices.

As an example, a hybrid integrated circuit device in which the surface of a metal substrate is subjected to an insulation treatment will be described with reference to FIGS. 1 to 4. First, as shown in FIG. 3 and FIG. 4, there is a metal substrate (1), the surface of which is insulated. Here, Al is used as a metal substrate, and the surface thereof is anodized to form aluminum oxide (2), and a thermosetting resin, for example, an epoxy resin (3) is further deposited on the aluminum oxide (2) to form a double layer. Insulation processing is performed.

On the metal substrate (1), for example, FIG.
As described above, conductive paths (4) and (5) made of Cu are provided, and the conductive paths are integrated with or separate from the electrode terminals (6) and (7) provided around the substrate (1). Become a body,
And it is electrically connected. The electrode terminal (6) is a signal input terminal, and although not shown in the drawing, the conductive path (4) extends to the input part of the mounted component mounted on the metal substrate (1) and is electrically connected to this. Connected to each other.
The electrode terminal (7) is a GND terminal, and the conductive path (5) is laid as a GND wiring on the metal substrate (1) and, if necessary, is also electrically connected to the mounted component. In addition, thin metal wires are used because of the necessity of connecting with mounted components and crossing over wiring. Therefore, a predetermined circuit is achieved by the mounted parts, the fine metal wires, the conductive paths, and the like. Here, the mounted components are Tr chip, L
SI chips, chip resistors, chip capacitors, transformers and other external parts.

The above circuit is, for example, as shown in FIG. 5, and will be described later. Further, the discharge electrode of the present invention is provided between the conductive path (4) and the electrode terminal (6) and between the conductive path (5) and the electrode terminal (7). The first discharge electrode (8) and the second discharge electrode (9) are
Although it is integrated with the conductive path here, there is no problem even if it is a separate body. At least a part of the first discharge electrode (8) and at least a part of the second discharge electrode (9) face each other, and are provided with a gap of about 300 μm, and a film thickness of about 35 μm.
μm. Also, for the convenience of wire bonding, Ni plating is applied on the bonding pad,
Ni is also used for the discharge electrodes (8) and (9) by utilizing this process.
(10) is applied. Further, for environment resistance, this Ni may be adhered to the electrode terminals and the conductive paths. Furthermore, an epoxy-based passivation film (11) is provided on the entire surface of the insulating substrate (1), and if necessary, the power Tr or the like for generating heat is potted with silicone or the like. Further, although omitted in the figure, a portion that constitutes a circuit,
Here, except for the region where the electrode terminal group is provided, a metal or insulating case is mounted on the surface to prevent corrosion and the like due to the external atmosphere. The area shown by the alternate long and short dash line here indicates the portion where the side wall of this case abuts,
An adhesive sealant is provided and sealed.

The discharge electrode has a high discharge voltage when it is coated with the resin (11), so that the portion indicated by the dotted line is exposed in the hollow portion of the case. If the dielectric such as resin is covered, the discharge path deteriorates and changes over time. Therefore, considering reproducibility, it is preferable that an inert gas or the like be enclosed in the case. It's air.

In order to prevent noise from the electrode terminal (6) from escaping from the conductive path (4) first, the noise is provided in the vicinity of the seal area and arranged as close to the terminal as possible.
A power supply was applied to the hybrid integrated circuit, the device was actually operated, and noise generated from the noise generator was added to the electrode terminal (6). According to experiments, ± 5 KV, ± 10 KV,
A surge of ± 15 KV was applied 10 times at a rate of once per second, and the result was examined. However, noise could be satisfactorily discharged to GND without failure of the internal circuit.

On the other hand, when the resin (11) is coated,
At a discharge voltage of +5 KV, a malfunction (latch-up) occurred from the beginning, and at a discharge voltage of -5 KV, the internal circuit malfunctioned (latch-up) at the 10th discharge.
Therefore, when the discharge part is covered with the resin (11), the discharge effect which is the point of the present invention occurs, but the result is worse than that of the exposed discharge electrode.

In the lower layer of the discharge electrodes (8) and (9),
Since the epoxy resin (3) is adhered, there is a problem that the resin is carbonized by sparks generated by electric discharge. Therefore, if a large noise is rarely introduced, this structure is sufficient, but if it frequently occurs, it is necessary to remove the resin (3). In this case, when the epoxy resin covering the discharge part is removed, if the lower layer of the discharge part is also removed, the short circuit due to the carbonization phenomenon can be prevented.

For example, when a conductive path is printed by screen printing on a ceramic substrate and a discharge electrode is formed by sintering, the carbonization phenomenon does not occur because there is no resin in the lower layer. Further, in the case of the liquid crystal display device of FIG. 8, address lines and data lines, gate lines and drain lines are directly formed on the glass substrate. Therefore, if the discharge electrode is made of the same material, the lower layer is made of resin. There is no problem so there is no problem.

On the other hand, it becomes necessary to select the discharge electrode as well.
For example, when the discharge electrode is made of only Cu, an oxide film is formed on the surface of Cu, the discharge voltage becomes high, and the internal circuit may be broken. Therefore, depending on the number of discharges, if the discharge voltage in the interval exceeds the surge voltage to be protected,
It is necessary for the main material to cover the surface of the metal material forming the oxide film with Ni that is difficult to oxidize or Au or Pt that does not oxidize. This problem can be solved by using only Au or Pt that does not oxidize.

On the other hand, the discharge electrodes (6) and (7) may be the ones shown in FIG. 2 other than FIG. This is because the facing portion is thin or sharp, and since the electric field is likely to be concentrated at the tip, the structure is such that discharge easily occurs. Alternatively, the eaves may be formed by etching as shown in FIG. 4 in a plan view having the discharge portion of FIG. 1 or 2. Specifically, it suffices to deposit the upper layer having a slower etching rate. Here, Ni is deposited on Cu. For example, if the upper layer is etched with ferric chloride etchant, the etching rate depends on the etching rate. You can easily make eaves.

Next, a specific structure will be described with reference to FIG. 7 shows a part of an on-vehicle electronic control circuit using the microcomputer of FIG. 6, in which the above-mentioned discharge electrode is provided instead of the capacitor C1. The rectangular ones arranged in two rows at the left end are the electrode terminals, which are arranged in a large number vertically along the side edges of the substrate.
(20) is a terminal to which a signal is input, and (21)
Is a GND terminal. As soon as the electrode terminal (20) exceeds the seal area shown by the chain line, the discharge electrode (22)
Are provided and are electrically connected to the conductive path (23) through the resistor R1 and the diode D1. In the case of FIG. 6, the conductive path (23) is connected to the conductive path (23) immediately after the resistor R1 by a thin metal wire.
3) is connected with a thin metal wire (24). The conductive path (23) is cut at the right end, but is connected to the microcomputer. Further, it is connected to the conductive path (25) via the capacitor C2 on the way, and this conductive path is connected to the GND terminal (2
It has been extended to 1). Here, the resistors R2 and Tr are omitted in the figure.

The conductive path (25) is divided into two parts in the vicinity of the diode D1, one of which extends to the GND terminal and the other of which extends to the discharge electrode (26). Therefore the discharge electrode (26)
Are connected to GND. Further, as described above, the discharge part is exposed in the hollow part of the case, and the terminal (2
Even if noise enters into 0), sparks are generated in the discharge part and the noise is absorbed by GND. Therefore, the capacitor C
Since 2 is arranged, further protection works and no noise is sent to the microcomputer. In addition, since the discharge electrode has reproducibility, the microcomputer does not detect an abnormality determination that the vehicle has the vehicle speed even though the engine is stopped. Therefore, the engine is not stopped and the vehicle can travel safely. it can.

The noise absorbing device of the present invention can also be applied as a discrete element. An example is FIG. 7 is applied to the metal substrate as shown in FIG. 3, where (40) is the metal substrate, (41) is its oxide film, and (4)
2) is an epoxy resin, (43) and (44) are discharge electrodes, and (45) and (46) are external leads. Further, the discharge electrode and the external lead may be integrally configured by this lead. The part indicated by the broken line is a region where the epoxy electrode is not applied and the discharge electrode is exposed. Although the case is omitted in the figure, it is actually provided. The case can achieve its function even if it is not necessary, but it is necessary to provide the case in consideration of oxidation of the discharge electrode, explosion proof, and the like.

In consideration of carbonization of the resin in the discharge part as described above, it is preferable that the substrate is ceramics, glass or the like to which the discharge electrode can be adhered without borrowing the adhesiveness of the resin. The film forming method is screen printing. What is later sintered to form electrodes,
It is suitable to use semiconductor technology such as sputtering and vapor deposition. Moreover, what applied to the liquid crystal display device is demonstrated using FIG. For example, the wirings arranged in the horizontal direction are gate lines, and a gate terminal is provided at the right end.
A drain line is provided in the vertical direction, and a drain terminal is provided at the upper end. Although not shown in the figure, a TFT is provided at this intersection, a display electrode is provided at the source side, and liquid crystal is aligned between the display electrode provided at the counter substrate side and this display electrode.

Here, the discharge electrodes (50) and (51) are provided only on the gate line, but originally, they are also provided on the drain line. The conductive path (52) is a GND wiring, and can be shared with, for example, a drain line provided above the gate line. Since the drain line is generally made of Al, it is necessary to deposit a metal that is hard to oxidize or does not oxidize on the discharge electrode (51). Further, in this case, the discharge electrode (51) has a two-layer structure.
Must be provided on the insulating layer below the drain line from the gate line of one layer through the through hole. Further, it is necessary to adjust the distance between the discharge electrodes so that the breakdown voltage at the intersection of the gate line and the GND line does not decrease due to the film thickness.

[0027]

As is apparent from the above description, for example, a discharge electrode which can be formed on the surface of a hybrid integrated circuit device at the same time as the step of forming this conductive path is used instead of the capacitor for absorbing noise or of this capacitor. By arranging them in parallel, it is possible to prevent noise from entering the internal circuit. In addition, this discharge electrode generally does not flow a large current during discharge,
It has reproducibility without elution of the electrode part. Moreover, since it has a very simple structure, it has an advantage that it can be achieved without adding a large number of steps. Therefore, it can be easily incorporated into the surface of a semiconductor substrate, a glass substrate used for liquid crystal, or the like. Particularly in the case of an active TFT or the like, it is very easy to form this discharge electrode by sharing it with some process because the process is complicated, but even a simple matrix etc. with a simple process can be formed. It is possible to However, it is necessary to provide a GND line that crosses over the data lines and address lines arranged in a grid in the vicinity of the terminals. In addition, by adjusting the interval between the discharge electrodes, the voltage that can be protected can be adjusted, and this can be easily handled for each model.

Further, it is necessary to provide a case for the purpose of protecting the circuit components and the discharge electrode, but by exposing the discharge electrode in the hollow portion of the case, it becomes possible to protect from a relatively low voltage. Further, by disposing it in the immediate vicinity of the contact portion (sealing portion) of the case, it becomes possible to discharge the surge without sending it into the circuit. Further, by forming the surface of the discharge electrode or the metal itself with a metal that is hard to be oxidized or not oxidized or exposing the discharge electrode, it is possible to prevent the change of the discharge voltage and realize a reproducible discharge electrode.

[Brief description of drawings]

FIG. 1 is a plan view of an electronic circuit device illustrating the present invention.

FIG. 2 is a plan view of an electronic circuit device illustrating the present invention.

3 is a cross-sectional view of FIG.

FIG. 4 is a sectional view of FIG.

FIG. 5 is a plan view illustrating an application example of the present invention.

FIG. 6 is a diagram illustrating a conventional noise absorption method.

FIG. 7 is a diagram when the present invention is applied to a discrete type.

FIG. 8 is a diagram when the present invention is applied to a liquid crystal display device.

[Explanation of symbols]

 4 Conductive Path 5 Conductive Path (GND) 6 Electrode Terminal 7 Electrode Terminal (GND) 8 Discharge Electrode 9 Discharge Electrode

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 26, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

However, these are destroyed when a large surge exceeding the rating enters, and it is impossible to restore these devices unless they are replaced with new ones, for example, if they are mounted types. FIG. 6 is a partial view of a circuit that controls, for example, an engine of a car using a microcomputer. S is an engine speed sensor and L is a vehicle speed sensor, each of which is connected to a microcomputer. The circuit on the right side of the arrow X is mounted on, for example, a hybrid integrated circuit.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

[0005]

Here, the capacitor C1 is used.
C2 and C2 are noise eliminators that absorb surges, but if a large surge causes the capacitor C1 to puncture, for example, a voltage larger than the power supply voltage will be applied to the input terminal of the connected microcomputer by line induction, etc., and the microcomputer will be latched up. I will let you. As a result, this microcomputer system becomes out of control.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

For example, when the discharge electrodes are exposed to the air, the air serves as a dielectric, and the distance between the discharge electrodes causes noise of a certain voltage or more to pass through between the discharge electrodes. To discharge. According to the experiment, when the separation distance is set to 300 μm and the electrode thickness is set to about 35 μm, it is possible to discharge the noise of 5 KV or more generated by the noise tester without any problem and to have a function as a noise removing device. It was This structure can be achieved simply by bringing the electrodes close to each other. For example, in the case of a hybrid integrated circuit, the electrodes can be formed at the same time when the wiring is formed. Therefore, it is possible to save the trouble of attaching a chip or the like as in the conventional case.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

In order to prevent noise from the electrode terminal (6) from escaping from the conductive path (4) first, the noise is provided in the vicinity of the seal area and arranged as close to the terminal as possible.
A power supply was applied to the hybrid integrated circuit, the device was actually operated, and noise generated from a noise generator was added to this electrode terminal (6). According to an experiment, a surge of ± 5 KV or more was applied, and the result was obtained. As a result of investigation, the noise was satisfactorily discharged to GND without any failure of the internal circuit.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

On the other hand, when the resin (11) is coated,
The discharge voltage increased and the internal circuit malfunctioned (latch-up). Therefore, when the discharge part is covered with the resin (11), the discharge effect which is the point of the present invention occurs, but the result is worse than that of the exposed discharge electrode.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Soichi Izumiya 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (5)

[Claims] 1. A substrate having at least a surface of insulating property, a conductive path provided on the substrate, and a mounting component electrically connected to the conductive path and achieving a predetermined circuit with the conductive path. In at least an electronic circuit device having the above, the conductive path includes at least a first conductive path through which noise easily enters from the outside of the substrate and a second conductive path electrically connected to ground. A first discharge electrode electrically connected to the first conductive path and a second discharge electrode electrically connected to the second conductive path between the second conductive path and the second conductive path. An electronic circuit device is characterized in that a part of the first discharge electrode and the second discharge electrode face each other and are close to each other. 2. A substrate having an insulating property at least on the surface, a plurality of electrode terminals provided around the substrate, a conductive path extending from the electrode terminal, and electrically connected to the conductive path, An electronic circuit device comprising at least a mounting component that achieves this conductive path and a predetermined circuit, a passivation film that covers the surface of the substrate, and a protection unit that substantially protects the portion that achieves the circuit except this terminal. In the above, the conductive path includes at least a first conductive path through which noise easily enters from the electrode terminal and a second conductive path electrically connected to the ground. And a second discharge electrode integral with the first conductive path and a second discharge electrode integral with the second conductive path, and a part of the first discharge electrode. The second discharge electrodes are opposed to each other and are in close proximity to each other, A first discharge electrode and a second discharge electrode are disposed in a hollow portion of the case which is close to the electrode terminal where the noise enters, and at least a discharge portion of the discharge electrode is exposed in the case. An electronic circuit device characterized by being provided. 3. The electronic circuit device according to claim 1, wherein at least the surfaces of the first discharge electrode and the second discharge electrode are made of a metal that is hard to be oxidized or is not oxidized. 4. The electronic circuit device according to claim 1, wherein a passivation resin is provided on the substrate, and the passivation resin is removed from at least the discharge portions of the first discharge electrode and the second discharge electrode. . 5. A substrate having at least a surface of insulation, electrode terminals provided at both ends of the substrate, and first discharge electrodes extending from the electrode terminals and having discharge portions facing each other. A noise removing device comprising a second discharge electrode and a protection means for protecting the discharge portion from the external atmosphere at least by exposing the discharge portion.