JP2007256535A - Electric element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric element which can stably operate even on increase drive voltages with reduced spaces between electrodes, and its manufacturing method. <P>SOLUTION: The electric element having electrodes formed on an insulation substrate or insulation film is housed in a case. The minimum distance at least between a pair of electrodes is 20 μm or less and a gas higher in insulation than dried nitrogen is filled between these electrodes. Especially, it is preferable that the high insulation gas contains an arc-suppressing gas. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric element in which a plurality of electrodes are formed on an insulating substrate or an insulating film, and a method for manufacturing the electric element, and more particularly, to an electric element having a minimum value of the electrode interval of 20 μm or less and a method for manufacturing the electric element.

  Light used in MEMS (Micro Electro Mechanical System) devices, printed circuit boards, or optical communication fields, which is a general term for electromechanical systems composed of minute parts manufactured using various electronic devices and semiconductor microfabrication technology In electrical devices that form a plurality of electrodes on an insulator substrate or insulator film, such as control devices, the element size has been reduced to reduce power consumption and improve productivity. The electrode spacing is being reduced.

  The reduction of the electrode width leads to an increase in the electric resistance of the line and the drive voltage increases. Therefore, replacement with a low resistance material is required. As the electrode spacing decreases, the applied electric field substantially increases.

Moreover, as shown in Patent Document 1, in a high-frequency device, a low dielectric constant material such as polyimide or benzocyclobutene is embedded between electrodes to reduce the capacitance generated between wirings. . Since these low dielectric constant materials generally have high insulation properties, a fine electrode filled with the low dielectric constant material can suppress discharge between the electrodes even in a high electric field. However, the manufacturing cost of these materials themselves is high, and in order to form a miniaturized electrode, etching processing for a low dielectric constant material, or gas is not included between the fine electrodes, and low stress conditions are used. It is essential to develop a technology for the process of exposing a part for power supply after curing at.
JP 2001-68375 A

  The problem to be solved by the present invention is to solve the above-mentioned problems, and suppress the complication of the manufacturing process and the increase of the manufacturing cost even when the drive voltage is increased or the electrode interval is narrowed, and is stable. It is another object of the present invention to provide an electric element operable and a method for manufacturing the same.

In the invention according to claim 1, in the electric element in which a plurality of electrodes are formed on the insulating substrate or the insulating film, the electric element is installed in the casing, and the minimum value of at least a pair of the electrodes is 20 μm or less. A gas having a higher insulating property than dry nitrogen is introduced between the electrodes.
The “electrode interval” in the present invention means not only the interval between a plurality of electrodes formed on the same insulator substrate, but also the interval between the electrodes formed on the front and back of the same insulator substrate, It includes various forms such as an interval between electrodes formed on different insulator substrates.

  The invention according to claim 2 is the electrical element according to claim 1, wherein the gas contains an arc extinguishing gas.

The invention according to claim 3 is the electric device according to claim 2, wherein the digestion arc gas is SF _6.

  The invention according to claim 4 is the electric element according to claim 2 or 3, wherein the partial pressure of the arc extinguishing gas is 0.1 atm or more.

  The invention according to claim 5 is the electrical element according to any one of claims 1 to 4, wherein the insulator substrate or the insulator film has any one of a piezoelectric effect, a pyroelectric effect, and an electro-optic effect. It is characterized by that.

  According to a sixth aspect of the present invention, in the electrical element according to the fifth aspect, an optical waveguide is formed on the insulator substrate or the insulator film, and the electrode is used for controlling a light wave propagating through the optical waveguide. It is an electrode.

  According to a seventh aspect of the present invention, in the method of manufacturing an electric element in which a plurality of electrodes are formed on an insulating substrate or an insulating film, and the minimum value of the electrode interval is 20 μm or less, the electric element is installed in a casing. The casing is vacuum purged, and then the casing is filled with a gas containing an arc extinguishing gas to seal the casing.

  According to an eighth aspect of the present invention, in the electrical element manufacturing method according to the seventh aspect, after the casing is vacuum purged, the partial pressure of the arc extinguishing gas is 0.1 to 5 atm. The case is characterized in that the case is filled with a gas containing an arc extinguishing property and the case is sealed.

  According to the first aspect of the present invention, there is provided an electric element in which a plurality of electrodes are formed on an insulator substrate or an insulator film, and even if the minimum value of the electrode interval is 20 μm or less, the gap between the electrodes is less than dry nitrogen. In addition, since a highly insulating gas is introduced, the discharge between the electrodes can be effectively suppressed without filling the electrodes with a low dielectric constant material. It is possible to provide a high-density electric element in which the electrode interval is narrower than that. Further, since only gas is introduced between the electrodes, it can be introduced very easily even between high aspect electrodes as compared with the conventional method of embedding a low dielectric constant material between the electrodes.

  In addition, since the electric element is installed in the casing and the casing is filled with a gas having a higher insulating property than dry nitrogen, the discharge phenomenon between the electrodes can be prevented over a long period of time. In addition, since the housing is used, the filling pressure can be made larger than the atmospheric pressure, and it is possible to provide an element that can suppress discharge more effectively and can substantially apply a higher electric field. .

  According to the invention according to claim 2, since the gas uses an arc extinguishing gas, the discharge can be suppressed extremely stably, and even if a discharge occurs, it is canceled instantly, so that the electrode can be prevented from being broken or damaged. It becomes possible.

According to the invention of claim 3, since the arc extinguishing gas is SF ₆ , it becomes possible to suppress the discharge more effectively.

  According to the fourth aspect of the present invention, since the partial pressure of the arc extinguishing gas is 0.1 atm or more, the discharge suppressing effect can be effectively expressed.

  According to the invention of claim 5, since the insulator substrate or the insulator film has any one of the piezoelectric effect, the pyroelectric effect, and the electro-optic effect, it is also effective for an electric element that easily generates a discharge phenomenon. Therefore, it is possible to suppress discharge.

According to the invention of claim 6, in the electrical element, an optical waveguide is formed on the insulator substrate or the insulator film, and the electrode is an electrode for controlling a light wave propagating through the optical waveguide.
By using the present invention, it is possible to set an electrode interval small, an electric field can be applied more efficiently, and a larger modulation degree can be obtained, such as production of a low drive voltage type optical modulator. Can be provided.

  According to the invention of claim 7, in the method of manufacturing an electric element, the electric element is installed in the casing, the casing is vacuum purged, and then the casing is filled with a gas containing an arc extinguishing gas, Since the casing is sealed, it is possible to form an atmosphere in which the electric element is always in contact with the arc extinguishing gas, and this state can be maintained for a long period of time, so that the discharge phenomenon can be effectively prevented. It becomes possible.

  According to the invention of claim 8, after vacuum purging the casing, the arc extinguishing gas partial pressure is left in a gas of 0.1 atm or more and 5 atm or less, and the gas containing the arc extinguishing property is contained in the casing. Filling and sealing the housing makes it possible to supply the arc-extinguishing gas to the electric element as necessary and to prevent problems such as liquefaction of the arc-extinguishing gas.

Hereinafter, the present invention will be described in detail using preferred examples.
The present invention provides an electrical element in which a plurality of electrodes are formed on an insulator substrate or an insulator film, wherein the electrical element is installed in a housing, and a minimum value of at least a pair of the electrodes is 20 μm or less. Is characterized in that a gas having a higher insulating property than dry nitrogen is introduced.
In particular, the filling gas preferably contains an arc extinguishing gas (SF ₆ , H ₂ , CO ₂ ).
In general, air or dry nitrogen is also used as an insulator, but discharge occurs when 5 kV or more is applied per 1 cm. The gas used in the present invention is limited to a gas having higher insulation than such dry nitrogen.

The electrical element to which the present invention is applied includes an electronic device element or MEMS element in which a plurality of electrodes are formed on an insulator substrate such as an SOI (silicon on insulator) substrate, Al ₂ O ₃ , MgO, or an insulator film, Or, there are printed circuit boards formed on glass epoxy resin, light control elements such as optical modulators and optical switches using a substrate having an electro-optic effect, and more preferably, these electric elements are accommodated in a housing. However, there is no particular limitation as long as the inside of the housing is hermetically sealed.

The present invention is particularly applicable when the insulator substrate or the insulator film used for the electric element has any one of a piezoelectric effect, a pyroelectric effect, and an electro-optic effect.
For example, examples of the substrate having an electro-optic effect, a piezoelectric effect, or a pyroelectric effect include lithium niobate, lithium tantalate, PLZT (lead lanthanum zirconate titanate), and a quartz-based material. These substrates generate pyroelectric effects and piezo effects due to pressure changes with changes in temperature, but since the electrical elements are surrounded by highly insulating gas, discharge due to accumulated charges is effectively suppressed. The

  The housing that houses the electric element has high mechanical strength, and is the same wire as the substrate (the insulating film body itself or a support body that supports the insulating film when the insulating film is used) constituting the electric element. A material having an expansion coefficient is preferable, and a stainless material such as SUS303 or SUS304, Kovar, or a resin package can be suitably used. The housing is composed of a case and a lid so that the housing can be hermetically sealed after accommodating the electric element.

The case housing the electric element is hermetically sealed by seam welding the case and the lid. At this time, the casing is filled with an arc extinguishing gas such as SF ₆ , H ₂ , and CO ₂ .
In particular, SF ₆ gas is a chemically stable, non-toxic and odorless gas that has about three times the insulation performance and about 100 times the arc extinguishing ability (the ability to extinguish a high-temperature discharge (spark)). is doing. As a method of use, the arc extinguishing effect becomes higher as the pressure is increased. However, since the liquid is liquefied when the filling pressure is too high, it is desirable to use in a range of 0.3 Pa to 0.5 MPa.

The arc extinguishing capability is greatly affected by the absolute amount of arc extinguishing gas. More preferably, the arc extinguishing capability can be expected to be sufficiently expressed by setting the partial pressure of the arc extinguishing gas to 0.1 atm or more. . Further, in order to prevent the arc extinguishing gas from being liquefied as the filling pressure is increased, it is preferable to use it at 5 atm or less (0.5 MPa).
Furthermore, as other gas to be combined with the arc-extinguishing gas, CO ₂ , CF ₄ , N ₂ and He are preferable for stably expressing the performance of the arc-extinguishing gas. Moreover, these gases can be used also for the leak test which test | inspects the sealing state of a housing | casing, and are more preferable gas. It is also known that the N ₂ / CO ₂ / SF ₆ mixed gas has a higher mixing ratio than the case of using SF ₆ alone.

  The fields targeted by the present invention are, for example, transformers that handle large voltages exceeding 1 kV, insulating switchgears that are gas-filled in disconnectors, circuit breakers, grounding devices, lightning arresters, etc. It is not intended to suppress the phenomenon in which a large voltage is applied from the outside and discharges itself. The external voltage applied to the electric element according to the present invention is about 50 V or less. However, since the distance between the electrodes is as narrow as 20 μm or less, it is intended for an electric element in which the electric field applied between the electrodes is substantially increased. This is because such an electric element needs a function of protecting the electrode.

  Furthermore, in a device using a semiconductor as a substrate, a leakage current flows inside the substrate because the substrate itself is semiconductive, and when an overvoltage is applied, an insulating layer or a pn junction inside the substrate is destroyed. Leading to failure. On the other hand, in a device using a dielectric substrate, there is almost no current leakage, and when an overvoltage is applied, discharge between current-carrying electrodes and creeping discharge along the substrate or film interface occur. In the case of a small, high-frequency device, a large voltage and a large current are not energized. However, because the electrode spacing is small, even if the applied voltage is low, the electric field is large and discharge is likely to occur, and since the cross-sectional area of the electrode is small, even if a weak discharge occurs, the electrode breaks down and the device fails. .

  In general, in order to suppress discharge, it is effective to cover with insulating oil, highly insulating resin, or highly insulating gas. Insulating oils and insulating resins have a dielectric constant larger than that of vacuum or gas, which is disadvantageous in designing and manufacturing a high-frequency device, and has a disadvantage that microwave loss is large. On the other hand, a highly insulating gas has advantages such as low dielectric constant, low loss, nonflammability, and light weight compared to insulating oil and insulating resin, and is suitable for manufacturing a small and high frequency device. Further, in order to suppress the occurrence of discharge, it is more effective not only to suppress the discharge by simply increasing the insulation of the atmospheric gas, but also to erase the charge using an arc extinguishing gas.

Moreover, the gas containing the arc extinguishing gas can be filled in the casing by the following procedure.
(1) An electric element is installed in a housing.
(2) The housing is accommodated in a vacuum vessel and vacuum purge is performed. Preferably, unnecessary gas can be discharged by vacuum purging while heating. The heating time is preferably 1 to 6 hours.
(3) A gas containing the arc-extinguishing gas, in which the partial pressure of the arc-extinguishing gas is 0.1 atm or more and 5 atm or less is introduced into the vacuum-purged vacuum vessel.
(4) The case is left in the vacuum container for a while, and the case is sufficiently filled with a gas containing an arc extinguishing gas.
(5) Seal the housing and take the housing out of the vacuum vessel.

Example 1
A light control element was produced as an electric element.
An optical waveguide was formed on a LiNbO ₃ substrate using a Ti diffusion method, and then a coplanar electrode was formed by electrolytic plating using a resist pattern as a guide. The height of the Au electrode is 20 μm, and the minimum value of the electrode interval is 5 μm.
After dicing into a light control element using a dicing saw, the light element was fixed in a case made of SUS303. The introduction hole of the optical fiber connected to the optical element was sealed with solder.
The housing containing the optical element was filled with SF ₆ gas. The filling pressure was 1 atm. The case and lid constituting the housing were seam welded and hermetically sealed.

(Evaluation methods)
A direct voltage was applied between the electrodes at 20, 50, 100, and 200 V, respectively, and the presence or absence of electrode breakage was examined with a stereomicroscope. The breaking condition of the electrode was evaluated in the following three stages.
○: No breakage or breakage in the electrode △: Damage is confirmed but does not affect the operation of the element ×: Breakage is confirmed and affects the operation of the element

(Comparative Example 1)
It was manufactured in the same manner as in Example 1 except that polyimide was filled between the electrodes and dry nitrogen was used as a gas to be sealed in the housing, and evaluation was performed in the same manner.

(Comparative Example 2)
It was produced in the same manner as in Example 1 except that the gas enclosed in the housing was synthetic air containing a slight amount of He, and was similarly evaluated.

  The evaluation results are shown in Table 1. From the evaluation results shown in Table 1, it is clear that Example 1 of the present invention can effectively prevent electrode breakage and breakage to the same extent as in the case of filling polyimide between conventional electrodes (Comparative Example 1). became.

In the present embodiment, the light control element using the LiNbO ₃ substrate has been mainly described, but it is needless to say that the present invention can be applied to other materials as well.

  As described above, according to the present invention, in an electrical element in which a plurality of electrodes are formed on an insulator substrate or an insulator film and a method for manufacturing the same, a gas having a higher insulating property than dry nitrogen is introduced between the electrodes. As a result, it is possible to provide an electric element that can operate more stably even when the minimum value of the electrode interval is 20 μm or less, and a manufacturing method thereof. In addition, it is not necessary to use a conventional low dielectric constant material such as polyimide, and it becomes possible to suppress the complexity of the manufacturing process and the increase in manufacturing cost.

Claims (8)

In an electrical element having a plurality of electrodes formed on an insulator substrate or insulator film,
The electrical element is installed in a housing;
At least the minimum value of the distance between the pair of electrodes is 20 μm or less,
An electric element, wherein a gas having a higher insulating property than dry nitrogen is introduced between the electrodes.   The electric element according to claim 1, wherein the gas contains an arc extinguishing gas. The electric element according to claim 2, wherein the arc extinguishing gas is SF ₆ .   The electric element according to claim 2 or 3, wherein the partial pressure of the arc extinguishing gas is 0.1 atm or more.   5. The electrical element according to claim 1, wherein the insulator substrate or the insulator film has any one of a piezoelectric effect, a pyroelectric effect, and an electro-optic effect. 6.   6. The electric element according to claim 5, wherein an optical waveguide is formed on the insulator substrate or the insulator film, and the electrode is an electrode for controlling a light wave propagating through the optical waveguide. Electrical element. In the method of manufacturing an electric element in which a plurality of electrodes are formed on an insulator substrate or an insulator film, and the minimum value of the electrode interval is 20 μm or less.
The electrical element is installed in a housing;
Vacuum purging the housing;
Then, the casing is filled with a gas containing an arc extinguishing gas, and the casing is sealed. 8. The method of manufacturing an electric element according to claim 7, wherein after the casing is vacuum purged, the arc extinguishing gas partial pressure is left in a gas of 0.1 atm or more and 5 atm or less to be extinguished in the casing. A method for manufacturing an electrical element, wherein an arc-containing gas is filled and the casing is sealed.