JP2001052587A - Microrelay - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a substrate from a silicon wafer, realize a desired isolation characteristic and insertion loss characteristic even when processing a high-frequency signal, and prevent generation of unnecessary radiation. SOLUTION: This microrelay has an upper contact part 15a electrically conducted to a moving contact 15, exposed on the upper surface of a moving substrate 2; and a cap member 3 covering the moving substrate 2, provided to a fixed substrate 1. The cap member 3 is formed with a conductive part 19 connected to the upper contact part 15a when the moving substrate 2 is not driven, while the conductive part 19 is grounded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a micro relay.

[0002]

2. Description of the Related Art Conventionally, as a micro relay, for example,
A movable substrate, which is a movable electrode, is disposed opposite to a fixed substrate, which is a fixed electrode, and a voltage is applied between the two electrodes to generate an electrostatic attraction, thereby driving the movable substrate, and the lower surface of the movable substrate is driven. In some cases, the formed movable contact is brought into contact with and separated from both fixed contacts formed on the upper surface of the fixed substrate, thereby conducting / cutting off the signal wiring extending from each fixed contact. Generally, a silicon wafer that is easy to process is used for each of the substrates. The signal wires and contacts are formed on the silicon wafer via an insulating film.

[0003]

However, the insulating film formed on the surface of the silicon wafer is very thin, on the order of one thousand to several thousand angstroms. For this reason, large capacitive coupling may occur between the contact and the electrode. In addition, the parasitic capacitance between the signal lines increases. Therefore, when handling a high-frequency signal, desired isolation characteristics (pass loss characteristics) and insertion loss characteristics (reverse attenuation characteristics) cannot be secured.

[0004] The conductors that make up the contacts and signal wiring are:
Since it is formed on a silicon wafer via a very thin insulating film, unnecessary radiation is generated depending on the magnitude of the power.

On the other hand, if a glass wafer or GaAs is used, the above problem can be solved, but these materials are more expensive than a silicon wafer. Therefore, it is desired to use a silicon wafer which is inexpensive and easy to process.

Accordingly, the present invention is directed to a case where a substrate is formed of a silicon wafer and a high-frequency signal is handled.
It is an object of the present invention to provide a micro relay capable of obtaining desired isolation characteristics and identification of insertion loss and preventing generation of unnecessary radiation.

[0007]

According to the present invention, as a means for solving the above-mentioned problems, a movable substrate is disposed to face a fixed substrate, and a voltage is applied between the two substrates to generate an electrostatic attraction. By driving the movable substrate, the movable contact formed on the lower surface of the movable substrate is brought into contact with and separated from the two fixed contacts arranged side by side on the upper surface of the fixed substrate, so that the signal wiring extending from each fixed contact is electrically connected. In the micro relay to shut off,
Conducting the movable contact, and providing an upper contact portion exposed on the upper surface of the movable substrate, providing a cap member on the fixed substrate, covering the movable substrate, the cap member, when the movable substrate is not driven, A conductive portion connected to the upper contact portion is formed, and the conductive portion is grounded.

With this configuration, when the contacts are separated, the movable contact is grounded from the through-hole through the upper contact portion and the conductive portion formed on the cap member, and is capacitively coupled to the movable substrate as the movable electrode. Absent.

The conductive portion is formed on a lower surface of the cap member and is in contact with and separated from the movable contact, and a through-hole communicating the upper and lower surfaces of the cap member with the lower conductive portion. A lower surface-side conductive portion that is connected and grounded and that is formed on the lower surface of the cap member and that comes into contact with and separates from the upper contact portion; and a lower surface-side conductive portion and the fixed substrate. And a connection portion for connecting the provided grounding pad.

[0010] With this configuration, a microstrip line can be formed in which the grounded lower surface side conductive portion is used as a substrate and the signal wiring is used as a strip conductor, and a high-frequency signal can be appropriately propagated.

Further, the present invention provides a means for solving the above-mentioned problems, in which a movable substrate is disposed to face a fixed substrate, and a voltage is applied between the two substrates to generate an electrostatic attraction. A micro-relay that drives and disconnects a movable contact formed on the lower surface of the movable substrate to and from two fixed contacts arranged side by side on the upper surface of the fixed substrate, thereby conducting / interrupting between signal wires extending from each fixed contact. Forming a recess on the upper surface of the fixed substrate, covering the entire upper surface with an insulating film,
An insulating portion is further provided in the concave portion, and the signal wiring is formed on an upper surface of the insulating portion.

With this configuration, the insulating portion provided in the concave portion reduces the parasitic capacitance between the signal wirings, and a desired isolation characteristic can be obtained.

In particular, it is preferable that the insulating portion is made of low melting point glass since an insulating layer having a predetermined thickness can be easily formed.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1A is a perspective view of a micro relay according to the present embodiment. The micro relay includes a fixed substrate 1, a movable substrate 2, and a cap member 3.

The fixed substrate 1 is, as shown in FIG.
It forms a fixed electrode by itself in the form of a sheet. A concave portion 4 is formed on the upper surface of the fixed substrate 1, and the entire upper surface is covered with an insulating oxide film 9. Further, an insulating portion 5 is provided in the concave portion 4. Since the insulating portion 5 is made of low-melting glass (glass frit), heat treatment can be easily performed, and the insulating portion 5 can be made sufficiently thicker than an oxide film. The insulating portion 5 is made of a CVD (Chemical Vap).
or Deposition). On the upper surface of the fixed substrate 1, the signal wirings 6a, 6b,
Also, pads 7a, 7b, 7c, 7d are formed. Most of the signal wirings 6a and 6b are formed directly on the upper surface of the insulating section 5, and one ends of the signal wirings 6a and 6b are fixed contacts 8a and 8b arranged at predetermined intervals. Also, the signal wiring 6
a, 6b and pads 7a, 7b, 7c, 7d
Are formed on the upper surface of the insulating oxide film 9, and the signal wires 6 a and 6
The other end of b is connected to pads 7a and 7b. The pads 7c and 7d are electrically connected to the fixed substrate 1 and the movable substrate 2, respectively, so that a voltage can be applied between the two. Lead lines (not shown) are connected to the pads 7a, 7b, 7c, 7d, respectively.

The movable substrate 2 is, as shown in FIG.
It has a sheet-like shape and includes a peripheral guide portion 10 and a movable electrode portion 11 inside the guide portion 10. The upper and lower surfaces of the movable substrate 2 are covered with an insulating oxide film 12 except for a connection portion 2a on the lower surface electrically connected to the pad 7c. The movable electrode portion 11 has first slits 13 formed on both sides and can be bent downward. In addition, the central part of the movable electrode part 11 is shown in FIG.
As shown in (d), a rectangular through hole 14 is formed, and the movable contact 15 on the lower surface side and the upper contact portion 15a on the upper surface side communicate with each other by plating or the like. On both sides of the movable contact 15, second slits 16 are formed.
Can be reliably closed to both fixed contacts 8a and 8b.

As shown in FIG. 2A, the upper and lower surfaces of the cap member 3 are covered with an insulating oxide film 3a, and an upper conductive layer 18 is provided on the upper surface thereof. The lower surface-side conductive layer 19 is formed on each of the layers 17 by plating or the like. Both conductive layers 18 and 19 are shown in FIG.
As shown in (2), they are electrically connected via through holes 20 provided at two places. The upper conductive layer 18 is grounded via a lead (not shown), and the lower conductive layer 19 is in contact with an upper contact portion 15a that is electrically connected to the movable contact 15 when the movable electrode portion 11 is not driven. .

Next, a method of manufacturing the micro relay having the above-described configuration will be described.

First, as shown in FIG. 3A, a concave portion 4 is formed on the upper surface of a fixed substrate silicon wafer (fixing wafer) 100, and the upper surface is covered with an insulating oxide film 9. And
An insulating portion made of low-melting glass is provided in the concave portion. Subsequently, as shown in FIG.
The signal wirings 6a and 6b are formed by plating, screen printing, or the like.
The fixed substrate 1 is completed by forming the pads 7a, 7b, 7c, 7d.

As shown in FIG. 3C, a through hole 14 is formed in the center of a silicon wafer for movable substrate (movable wafer) 101, and the upper and lower surfaces are covered with an insulating oxide film 12. Then, as shown in FIG. 3D, an upper contact portion 15a made of Au / Cr and a movable contact 15 are formed on the upper and lower surfaces of the central portion of the movable wafer 101 by sputtering, vapor deposition, plating, screen printing, or the like. Then, both are electrically connected via the through hole 14.

Next, as shown in FIG. 4A, the movable wafer 101 is joined and integrated with the fixed substrate 1. And
By dry etching, the first wafer is
The movable substrate 2 is completed by providing slits 13 (see FIG. 2) and forming second slits 16 (see FIG. 2) on both sides of the movable contact 15. As described above, since the movable substrate 2 is formed in a state where the movable substrate 2 is joined to and integrated with the fixed substrate 1, the movable substrate 2 is not deformed during manufacturing.

On the other hand, as shown in FIG. 4B, a recess 17 is provided on the lower surface of the cap member silicon wafer (cap wafer) 103, and a through hole 20 penetrating from the upper surface to the recess 17 is formed. Then, as shown in FIG. 4C, after the upper and lower surfaces are covered with the insulating oxide film 3a, the upper surface side conductive layer 18 is formed on the upper surface and the lower surface side conductive layer 19 is formed on the recess 17 by plating or the like, respectively. The cap member 3 is completed by electrically connecting the conductive layers 18 and 19 via the through hole 20.

Subsequently, as shown in FIG. 4D, the movable substrate 2 in which the cap member 3 is integrated on the upper surface of the fixed substrate 1 is formed.
Join directly to In this state, the movable contact formed on the movable substrate 2 is grounded when the upper contact portion 15 a contacts the lower conductive layer 19 of the cap member 3.

The operation of the micro relay completed as described above is as follows.

That is, if no voltage is applied between the electrodes 1 and 2, no electrostatic attraction is generated, and the movable electrode section 11 is maintained in a horizontal state by its own elastic force. Thereby, the upper contact portion 15a of the movable contact 15 is
It contacts the lower conductive layer 19 of the cap member 3. The movable contact 15 is formed from the lower conductive layer 19 through the through hole 2.
0, grounded via the upper contact portion 15a and the upper surface side conductive layer 18. Therefore, there is no capacitive coupling between the movable contact 15 and the fixed contacts 8a and 8b opposed thereto,
Desired isolation characteristics and insertion loss characteristics can be obtained. Also, the signal wiring 6a,
Since 6b is formed on the upper surface of the insulating portion 5 having a large thickness, the parasitic capacitance can be reduced, and unnecessary radiation does not occur.

Here, when a voltage is applied between the two electrodes 1 and 2 to generate an electrostatic attraction, the movable electrode portion 11
The movable contact 15 is closed to both fixed contacts 8a and 8b. Thereby, a signal propagates between both signal wirings 6a and 6b. In this case, since the lower surface side conductive layer 19 provided on the cap member 3 is grounded, the signal wires 6a, 6b
And a microstrip line is formed. Therefore, even if the signal to be propagated has a high frequency, the insertion loss characteristic and the isolation characteristic can be maintained in desired states. Further, when the movable electrode portion 11 is driven, the air resistance is reduced by the through holes 20, so that the movable electrode portion 11 operates smoothly.

In the above embodiment, the cap member 3
5, the lower conductive layer 19 is grounded via the through hole 20 and the upper conductive layer 18, but as shown in FIG.
1 may be grounded. According to this, it is possible to make the inside highly airtight.

In the above embodiment, the upper contact part 15a and the movable contact 15 are formed on the upper and lower surfaces of the movable substrate 2, respectively.
Although both were electrically connected through the through hole 20, the upper contact portion 15a and the movable contact 15 were simply
Alternatively, conduction may be achieved by doping the center portion of the semiconductor device 01 with an impurity.

[0030]

As is apparent from the above description, according to the micro relay of the present invention, when the movable substrate is not driven,
Since the movable contact is grounded via the conductive part of the cap member, there is no capacitive coupling between the movable contact and the movable electrode,
Desired isolation characteristics and insertion loss characteristics can be obtained, and unnecessary radiation can be prevented.

In particular, since the lower conductive portion is formed on the cap member, it is possible to form a microstrip line with the signal wiring, and to appropriately propagate a high-frequency signal.

Further, since the entire upper surface of the fixed substrate is covered with an insulating film, an insulating portion is further provided in a concave portion formed on the upper surface, and the signal wiring is formed on the upper surface of the insulating portion, thereby suppressing the parasitic capacitance between the signal wirings. Thus, a desired isolation characteristic can be obtained.

Since the insulating plate is made of low-melting glass, the processing is facilitated and the processing efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view (a) of a microrelay according to the present embodiment and a plan view (b) thereof.

FIG. 2 is an exploded perspective view of FIG.

FIG. 3 is a cross-sectional view taken along the line AA of FIG. 1 (b) illustrating a manufacturing process of the micro relay according to the embodiment.

FIG. 4 is a cross-sectional view taken along the line AA of FIG. 1 (b) showing a manufacturing process of the micro relay according to the embodiment.

FIG. 5 is a perspective view showing a cap member of a micro relay according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fixed board 2 ... Movable board 3 ... Cap member 4 ... Concave part 5 ... Insulation part 6a, 6b ... Signal wiring 11 ... Movable electrode part 15 ... Movable contact 15a ... Upper contact part 18 ... Upper surface side conductive layer 19 ... Lower surface side conductive Layer 20: Through hole

Claims (5)

[Claims] A movable contact formed on a lower surface of the movable substrate by driving the movable substrate by disposing a movable substrate facing a fixed substrate and applying a voltage between the two substrates to generate an electrostatic attraction. Is connected to and separated from both fixed contacts arranged side by side on the upper surface of the fixed substrate, thereby conducting / cutting off signal wiring extending from each fixed contact. An upper contact portion that is exposed on the upper surface; a cap member that covers the movable substrate is provided on the fixed substrate; and a conductive portion that is connected to the upper contact portion when the movable substrate is not driven is formed on the cap member. A microrelay, wherein the conductive portion is grounded. 2. The conductive portion includes: a lower surface-side conductive portion formed on a lower surface of the cap member and in contact with and separated from a movable contact; and a through hole communicating with the upper and lower surfaces of the cap member to the lower surface-side conductive portion. 2. The microrelay according to claim 1, wherein the microrelay comprises a top-side conductive portion that is connected via a ground and is grounded. 3. The lower conductive part, which is formed on the lower surface of the cap member and comes into contact with and separates from the upper contact part, connects the lower conductive part to a ground pad provided on the fixed substrate. 2. A connection part comprising:
Micro relay according to the above. 4. A movable contact formed on a lower surface of the movable substrate by disposing a movable substrate on the fixed substrate so as to apply a voltage between the two substrates to generate an electrostatic attraction, thereby driving the movable substrate. Is connected to and separated from both fixed contacts arranged side by side on the upper surface of the fixed substrate, thereby conducting / interrupting between signal wirings extending from the respective fixed contacts. A microrelay, wherein the whole is covered with an insulating film, an insulating portion is further provided in the concave portion, and the signal wiring is formed on an upper surface of the insulating portion. 5. The micro relay according to claim 4, wherein the insulating portion is made of a low melting point glass.