JPH02100224A - Electrostatic type relay - Google Patents

Abstract

PURPOSE:To permit to attempt enhancement in the mechanical strength of a moving segment and also to attempt facilitating the drive voltage adjustment, by providing moving contact layers formed on a moving segment via insulating thin-films, and fixed contact layers formed on the main surface of a substrate to be opened and closed on the moving contact layers. CONSTITUTION:A semiconductive base material is used to form a moving segment 11 pivotally supported by a monocrystallized semiconductive base material arranged oppositely via spacing means 9 on the main surface of an electrical insulating substrate 1 so that the moving segment is set on its head side to be rotatable and displaceable toward the main surface side of the substrate 1. Fixed-side electrode layers 2, 3 opposed to this moving segment 11 and for being combined with the moving segment 11 to compose driving counter electrodes, are formed on the main surface of the substrate 1, and then moving contact layers 14, 15 are formed on the moving segment 11 via electrical insulating films 13, 16 so that fixed contact layers, 4 to 7 being opened and closed by the moving contact layers 14, 15 are formed on the main surface of the substrate. Since in this manner, the moving segment 11 is formed out of the monocrystallized semiconductive base material that is a body different from the electrical insulating substrate, is facilitated. Thus, the mechanical strength of the moving segment can be enhanced, further with a space between the moving segment 11 and the substrate 1 being adjustable by the spacing means 9 so that the drive voltage adjustment may become also easier.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrostatic relay using electrostatic force as a driving source.

<Prior art and problems> Conventionally, as shown in FIG. 17, in this type of relay, an insulating thin film of silicon oxide (S i02 ) is formed as a mask 102 on a base 101 made of a silicon single crystal wafer (Si). A conductive thin film 103 is formed on the main surface of the base 101 through a mask 102 by vapor deposition or sputtering, and this conductive thin film 103 is
A driving electrode layer 104, a base electrode Ntoe for installing the movable contact piece 105, and a fixed contact layer 107 are respectively formed on the substrate 1 facing the driving electrode layer 104.
There is a method in which a concave portion 108 is formed by etching on the main surface of the mask 01, so that the - section of the mask 02 is set as a movable piece 108 consisting of a cantilever beam.

That is, this is the driving electrode layer 104 and the base 101.
By applying a DC voltage V between them, an electrostatic attraction force acts between the two 104 and 101, and the movable piece 109
is displaced downward so that the movable contact piece 105 comes into contact with the fixed contact layer 107, and the silicon substrate 101 can be microfabricated by a semiconductor thin film forming means, making it suitable for miniaturization.

However, in the above method, the movable piece 109 is made of a thin film of silicon oxide with a thickness of about lpm, so the mechanical strength is weak, and for example, bubbles generated during etching are severe, and loading and unloading into and out of the liquid tank is messy. If this is done, there is a risk of breakage due to vibration during use. Also,
If the cleaning after the etching process is insufficient, the movable piece 109 may stick to the bottom of the recess 108 due to the surface tension of the liquid.

In particular, since the movable piece 109 is extremely thin, warping occurs due to the difference in linear expansion coefficient between the two when forming the driving electrode layer 104, and any variation in this causes a large change in the driving force (contact pressure). becomes.

In addition, in order to maintain the depth of the recess 108, which is related to the driving force, to a constant small value, it is necessary to stop etching midway through, and for this reason, it is necessary to do things such as doping the silicon substrate 101 with P at a high concentration. It requires complicated techniques and is difficult to make.

<Object of the Invention> The present invention has been made to solve the above-mentioned problems of the conventional device, and it is possible to strengthen the mechanical strength of the movable piece, and to make it easy to adjust the driving voltage.

The aim is to provide electrostatic relays with excellent productivity.

<Structure and Effects of the Invention> The electrostatic relay according to the present invention is pivotally supported by a single crystal semiconductor base material which is disposed opposite to the main surface of an electrically insulating substrate via a spacer means, and the tip side is connected to the main surface of the substrate. A movable piece configured to be rotatably displaceable toward the surface is formed from the semiconductor base material, and a fixed side electrode layer, which together with the movable piece constitutes a driving counter electrode, is formed on the main surface of the substrate opposite to the movable piece. A movable contact layer was formed on the movable piece via an electrical insulating film, and a fixed contact layer that was opened and closed by the movable contact layer was formed on the main surface of the substrate. It is something.

As the semiconductor single crystal base material, a silicon single crystal wafer having a surface of the plane group (100) is used, a movable piece is formed by anisotropic etching, and the plane group is formed by anisotropic etching. (4) It is preferable in terms of microfabrication to arrange it relatively perpendicularly or parallel to the orientation facet formed parallel to 11).

According to this invention, since the movable piece is formed from a semiconductor single crystal base material separate from the electrically insulating substrate, microfabrication is easy and the mechanical strength is higher than that of a movable piece made of silicon oxide. Can be strengthened.

Furthermore, since the distance between the movable piece and the substrate can be adjusted using the spacer means, the driving voltage can be easily adjusted, and an easy-to-use device can be efficiently obtained.

In addition, by specifying the plane orientation of the single crystal semiconductor substrate, microfabrication of the movable piece, etc. can be performed with even higher precision, and it is also possible to make the movable piece thinner or to form a notch, etc. in its proximal pivot portion. For example, the movable piece can be easily displaced, and operability can be improved.

<Explanation of Examples> Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing an example of an electrostatic relay according to the present invention, and FIG. 2 is a sectional view taken along the line II--II in FIG. 1.

In the figure, l is an electrically insulating substrate, for example, a rectangular glass substrate, and its main surface has a pair of driving electrode layers 2 and 3 located at the center in the front and back direction (longitudinal direction).
are arranged side by side. 4°5 is the front drive electrode layer 2
A pair of fixed contact layers 6.7 on the front side are located in front of and formed on the main surface of the substrate 1, and 6.7 are located on the back of the drive electrode layer 3 on the rear side and are formed on the main surface of the substrate 1. A pair of fixed contact layers on the rear side are formed on the main surface. The electrode layer 2.3 and fixed contact layers 4-7 are formed by known means such as vapor deposition.

Reference numeral 8 denotes a semiconductor single crystal substrate, for example, a rectangular plate-shaped silicon single crystal wafer, which is attached to the substrate 1 through a mixture of a glass rod 9.9 as a spacer means and an adhesive 10.
It is pressed and fixed to the main surface side of the glass rod 9,
Alumina (AfL203) particles or the like may be used instead of 9.

The silicon single crystal wafer 8 is formed with a rectangular movable piece 11 surrounded by a Japanese letter frame portion 8A, and this movable piece 11 is coupled between the center in the front-rear direction and the frame portion 8A. The front piece 11A and the rear piece 1 center around the pivot portion 12.
1B is set to be swingable. This movable piece 11 is formed by forming, for example, an insulating thin film 13 of silicon oxide (not shown in FIG. 1) in a predetermined pattern as a mask on the upper surface of the wafer 8, and then etching the wafer 8. Formed into desired shape.

The front pieces 11A and IIB of the movable piece 11 each constitute a driving counter electrode with the electrode layer 2.3.

Reference numeral 14.15 denotes a movable contact layer fixed to the lower surface of the front end side of each of the front piece 11A and the rear piece 11B of the movable piece 11 via an insulating thin film 16 of silicon oxide (not shown in FIG. 1). , the movable contact layer 14 is the front fixed contact layer 4.
5, and the movable contact layer 15 is set to open and close the rear fixed contact R6°7.

After forming the movable piece 11 and the movable contact layer 14.15, the wafer 8 is bonded to the main surface side of the base 1 via the glass rod 9. In order to ensure accuracy, it is preferable to provide positioning marks 17 shown in FIG. 3 on the back surface of the base 1.

Next, the operation of the above configuration will be explained.

When a DC voltage is applied between the movable piece 11 and the front drive electrode layer 2, an electrostatic attraction force is generated between the front piece 11A of the movable piece 11 and the electrode layer 2, and the front piece 11A Cardinal branch 12
Since the movable contact layer 14 is bent and displaced toward the electrode layer 2 side using the fulcrum as a fulcrum, the movable contact layer 14 comes into contact with the fixed contact layer 4.5, and the re-fixed contact layer 4.
．． 5 spaces are closed. When the application of the DC voltage is cut off, the movable piece 11A returns to its original state due to the torsional restoring force of the pivot portion 12, and the refixed contact layer 4.5 is opened.

By applying a DC voltage between the movable piece 11 and the rear drive electrode layer 3, the rear piece 11B of the movable piece 11 also performs the same operation as described above.

Here, since the movable piece 11 is formed from the silicon single crystal wafer 8, fine processing is possible, and a piece with higher mechanical strength can be obtained compared to the conventional one formed from a thin film of silicon oxide. There is no fear that the movable piece 11 will break during manufacturing. Furthermore, since the movable piece 11 is suppressed from warping, the distance between the electrode layers 2 and 3 is kept constant, in other words, variation in contact pressure is suppressed, and reliability is improved.

Further, since the movable piece 11 is formed from a silicon single crystal wafer 8 separate from the base 1, the distance between the electrodes can be changed by selecting the spacer means 9 to obtain a desired driving force.

By the way, the movable piece 11 is obtained by finely processing the silicon single crystal wafer 8 by etching.
Anisotropic etching is used to perform more precise microfabrication.

When forming the movable piece 11 by anisotropic etching, the following should be kept in mind.

That is, the top surface of the silicon single crystal wafer 8 is (110)
In the case of a surface, the orientation Φ phaset (hereinafter,
(referred to as OF). (4)01) If the movable piece 11 is made into a rectangular shape, the OF
Although the side 11a parallel to OF is a precise straight line, the side 11b perpendicular to OF is jagged. If the mold is made obliquely to the OF, the shape will be complicated. Therefore, if the (100) plane is used, it is difficult to obtain a movable piece 11 with a precise shape.

On the other hand, the upper surface of the silicon single crystal wafer 8 is (100
) surface, if the mold is made diagonally to the OF, the 4th b
The shape is shown by the broken line in the figure, and it does not match the mask pattern, but the sides 11a and llb are parallel and perpendicular to the OF.
Accurate straight lines can be obtained to precisely match the mask pattern. Therefore, by considering the above-mentioned surface orientation, it is possible to easily obtain the movable piece 11 with high dimensional accuracy and high three-dimensional shape reproducibility. The possibility of malfunction caused by silicon remaining as a residual liquid is also reliably eliminated.

In addition to the above (100) plane. (4)10),. (4)01
), (100),. (4)10).

. Each surface of (4)01) is equivalent, and the above-mentioned advantage can be said to be a common property of the surface group (100). Also, regarding OF, the movable piece 11 is a group of surfaces. (4) It can be said that it is preferable to arrange it relatively perpendicularly or parallel to the OF formed parallel to 11). In addition, 1 side group. (4)11). (4)11), (110),. (4)11),. (4
)11).

By the way, if the movable piece 11 is formed as thin as possible,
Easy to displace and improves operability. This can be easily realized by etching the silicon single crystal wafer 8 in two stages from both the upper and lower surfaces of FIGS. 5a and 5b.

The one shown in Fig. 5a is formed by anisotropic etching from both directions of arrows a and b, and the one shown in Fig. 5b is formed by isotropic etching from the direction of arrow a, and from the direction of arrow is formed by anisotropic etching, and an extremely thin movable piece 11 is formed with respect to the frame portion 8A.

Normally, etching is performed to a depth di for thickness control from the direction of arrow a, and then etching is performed to a depth d2 from the direction of the arrow.When etching one side, the other side is etched with wax or the like. If the above-mentioned etching is performed first in the direction indicated by the arrow, negative pressure will be applied to the recess 8B (Figs. 5a and 5b), and the movable piece 11 will Care must be taken as there is a risk of deformation or destruction.

6 and 7 show an electrostatic relay to which the movable piece 11 formed by the two-stage etching method shown in FIGS. 5a and 5b is applied.

In this case, since the movable piece 11 is formed thinner than the frame portion 8A, the movable piece 11 can be easily displaced, and there is also an advantage that the movable piece 11 is protected by the frame portion 8A.

Furthermore, in order to facilitate the displacement of the movable piece 11, a thin wall portion 18 may be formed on the pivot portion 12 by isotropic etching, as shown in FIG. By forming the notch 19 in the movable piece 11 along the pivot portion 12, the stroke amount of the displacement of the movable piece 11 can be set to be large, making it easier to obtain sufficient contact pressure.

Furthermore, when the movable piece 11 is supported in a cantilever manner as shown in FIG. Displacement becomes easier.

By the way, when the movable piece 11 is operated, both the left and right corners on the tip side hit the base l side, and by repeating this,
If there is a risk that that portion may be damaged, a chamfered portion 21 may be formed as shown in FIG. 11.

Furthermore, if a bulge or the like is formed on the insulating thin film 16 of silicon oxide, which is a mask, corresponding to the corner, the corner of the movable contact layer 14 (15) laminated thereon may peel off, causing a short circuit accident. There is. Regarding this point, if a thin film of silicon oxide obtained by thermal oxidation is used as a mask, burrs will not be generated immediately after etching, which is convenient. Part 22
By setting it in a pre-notched shape as shown in FIG. 11, the above-mentioned fear of peeling is eliminated.

It is possible to prevent short circuit accidents from occurring.

FIG. 12 shows that when forming the movable piece ti, anisotropic etching is performed alternately from both the upper and lower surfaces, and a chamfered portion 23 is formed on the upper and lower surfaces of the tip side according to the pattern of silicon-brominated insulating thin JI 5113, 16. This is effective as a measure to prevent damage to the movable piece 11.

FIG. 13 and FIG. 14 show other embodiments of the present invention, in which front piece and rear piece portions 11A and IIB of the movable piece 11 are shown.
arm pieces 24A for fixing movable contacts protruding forward from the tips of the front and rear pieces 11A and IIA, respectively, on each side thereof;
24A and 24B.

This is a combination of 24B. This item is the arm piece 2 above.
4A and 24B ensure that the movable contact layers 14 and 15 contact the fixed contact layers 4 and 5 earlier than the front and rear pieces 11A and 11B, respectively, so there is no risk of short circuit.
Due to the bending of the arm pieces 24A and 24B, sufficient contact pressure can be easily obtained.

Further, in the above example, a recessed part lb having a step difference from the peripheral part la is formed on the substrate 1, and the bottom surface of the recessed part tb is the main surface of the substrate l, so that the peripheral part 1a is a spacer. Therefore, the spacer member can be omitted and the number of parts can be reduced. In addition, the above arm piece 2
4A.

The shape of 24B can be changed arbitrarily.

As another example of the present invention, for example, as shown in FIG. 15a, after the part of the pivot part 12 of the movable piece 11 is adhered to the substrate l, the pivot part 12 is cut along the cutting line to form a frame. The portion 8A may be removed and only the movable piece 11 left on the substrate 1 as shown in FIG. 15b.

The means for manufacturing the movable pieces 11 as described above can be applied to manufacturing a large number of movable pieces 11 by providing blocks for a large number of movable pieces 11 using a common substrate l.

Further, as shown in FIG. 16, patterns of a large number of movable pieces 11 are formed in a matrix on one silicon single crystal wafer 80, and this is bonded to the substrate 1 and each pattern is separated. It is also possible to make it possible to take out a large number of pieces.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an example of an electrostatic relay according to the present invention, FIG. 2 is a sectional view taken along the line II--II of FIG.
The figure is an explanatory diagram of means for aligning the substrate and the silicon single crystal wafer, and FIGS. 4a, 4b, and 4c are explanatory diagrams of the plane direction of the silicon single crystal. Figures 5a and 5b are cross-sectional views showing movable pieces thinly formed by different two-stage etching, and Figure 6 is an exploded view showing an electrostatic relay to which the movable pieces according to figures 5a and 5b are applied. The side view, FIG. 7, is a sectional view taken along the line ■-■ in FIG. 6, and FIG. 8. FIGS. 9 and 10 are perspective views showing examples of measures to assist the displacement of the movable piece, FIGS. 11 and 12 are illustrations of processing examples to prevent breakage and short circuit of the movable piece,
FIG. 13 is an exploded perspective view showing another example of the present invention, and FIG.
The figure is a cross-sectional view taken along line W-)IN of the one shown in Fig. 13, Figs. 15a and 15b are explanatory diagrams of a configuration in which the frame of the movable piece is removed and only the movable piece remains on the substrate, and Fig. 16 is a silicon monomer. FIG. 17 is a cross-sectional view showing the structure of a conventional electrostatic relay. 1...Substrate, la, 9...Spacer means, lb...
・Recessed part, 2.3...Fixed side electrode layer, 4, 5, 6.7
... Fixed contact layer, 8.80 ... Semiconductor single crystal base material. 8A... Frame part, 11... Movable piece, 12... Pivotal part, 13.16... Insulating thin film, 14.15... Movable contact layer, 18... Thin wall part, 19...・Notch part, 20
... recessed part, 21.23... chamfered part, 22... notch part. 24A, 24B...Arm piece.

Claims (10)

[Claims] (1) It is formed from an electrically insulating substrate and a semiconductor single crystal base material which is disposed facing the main surface of this substrate via a spacer means, and the tip side can be rotated toward the main surface of the substrate. a movable piece whose base end side is pivotally supported by the base material; a fixed side electrode layer which is formed on the main surface of the substrate opposite to the movable piece and constitutes a driving counter electrode with the movable piece; An electrostatic relay comprising: a movable contact layer formed on a movable piece via an insulating thin film; and a fixed contact layer formed on the main surface of the substrate and opened and closed by the movable contact layer. (2) The semiconductor single crystal base material is composed of a silicon single crystal wafer having a surface of plane group {100}, a mask pattern is formed on the upper and lower surfaces of this wafer, and the above movable piece is formed by anisotropic etching. , this movable piece is a surface group {011}
2. The electrostatic relay according to claim 1, wherein the electrostatic relay is disposed relatively perpendicularly or parallel to an orientation facet formed parallel to the orientation facet. (3) A mask pattern for defining the shape of the movable piece is formed on the upper surface of the silicon single crystal wafer, and a mask pattern for defining the thickness of the movable piece is formed on the lower surface, and the upper and lower surfaces are etched alternately. 3. The electrostatic relay according to claim 1, wherein a thin movable piece is formed on the wafer. (4) The electrostatic relay according to claim 1, 2 or 3, wherein a thin wall portion or a recess is formed by etching on the proximal pivot portion of the movable piece. (5) The electrostatic relay according to claim 1, 2 or 3, wherein notches are formed in the movable contact layer corresponding to both corners on the tip side of the movable piece. (6) The electrostatic relay according to claim 1, 2 or 3, wherein the movable piece has a chamfered portion formed in both the upper and lower directions at the distal end thereof. (7) Claim 1, wherein an arm piece for fixing the movable contact layer is integrally formed on the side surface of the movable piece and extends forward from the tip of the movable piece.
, 2 or 3. (8) The electrostatic relay according to claim 1, wherein a recessed portion having a step with a peripheral portion is formed on the substrate, a bottom surface of the recessed portion is a main surface, and the peripheral portion is set as a spacer means. (9) The electrostatic relay according to claim 2, wherein when the movable piece is formed from the silicon single crystal wafer, a frame portion surrounding the movable piece is separated at a pivot portion of the movable piece. (10) The electrostatic relay according to claim 2, wherein a silicon single-crystal ware having a large number of movable pieces is bonded to the substrate and can be divided into parts including each of the movable pieces.