JP2007279000A - Potential sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a size and a weight, to enhance sensitivity, to facilitate production, and to enhance degrees of freedom for design and the production. <P>SOLUTION: The potential sensor 10 includes a base member 11 comprising a semiconductor substrate, a vibrator 12 formed overhung-beam-likely with respect to the base material 11 by a semiconductor manufacturing technique, a detecting electrode 13 formed on a tip part surface of the vibrator 12 by the semiconductor manufacturing technique, and piezoelectric elements 14, 15 formed on a surface of the vibrator 12 by the semiconductor manufacturing technique. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a potential sensor that can measure the potential of an object to be measured in a non-contact manner, and particularly relates to a potential sensor manufactured using semiconductor manufacturing technology.

  Conventionally, a potential sensor is used to measure the potential of a measurement object such as a photosensitive drum of a copying machine or a wafer of a semiconductor production line.

  As shown in FIGS. 5 and 6, this type of conventional potential sensor 1 is roughly configured by a base plate 2 and a vibrating body 3 that is press-molded and attached to the base plate 2 in a cantilevered manner. In addition, a detection electrode 4 is provided at the tip of the vibrating body 3 so as to face the measurement object. The vibrating body 3 is provided with a piezoelectric element (not shown), and the piezoelectric element is connected to an oscillation circuit (not shown).

In the potential sensor 1 configured as described above, when the drive signal from the oscillation device is supplied to the piezoelectric element, the piezoelectric element is distorted, the vibrating body 3 vibrates, and the detection electrode 4 vibrates. . When the detection electrode 4 vibrates, the distance between the detection electrode 3 and the measurement object is periodically changed. Due to the periodic change of the distance, the distance between the detection electrode 3 and the measurement object is changed. The electrostatic capacity generated in the circuit changes periodically. As a result, an electric charge is induced in the detection electrode 3 to generate an AC signal, and the potential of the measurement object is measured based on the AC signal (see, for example, Patent Document 1 or 2).
JP-T-2005-501260 JP 2005-526227 A

  However, in the above-described conventional potential sensor 1, since the vibrating body 3 is formed by press working, a plate thickness of at least about 0.1 to 0.3 mm is required. Further, in order to stably support the vibrating body 3 by the base plate 2, the base plate 2 needs to have a mass of about several tens of times that of the vibrating body 3. For this reason, the conventional potential sensor 1 has a problem that it is difficult to reduce the size and weight.

  Further, since the piezoelectric element is manufactured separately from the vibrating body 3 and is bonded to the vibrating body 3, the number of parts is increased and an adhesion process is required. Therefore, there are problems that it takes much time to manufacture the potential sensor, and the degree of freedom in design and manufacturing is low.

  Further, when a plurality of vibrating bodies 3 are arranged on the base plate 2 using the above-described conventional technique, howling and interference may occur between the vibrating bodies 3 and the operation may become unstable. there were. Further, in this case, it is necessary to make a sufficient distance between the vibrating bodies 3, and it is necessary to increase the mass of the base plate 2 that supports the vibrating bodies 3, so that the potential sensor is increased in size. was there.

  Furthermore, in the potential sensor described in Patent Document 1, the mass of the base plate 2 can be reduced somewhat, but there is a problem that the movable range of the detection electrode 4 is reduced and the sensitivity as the sensor is reduced. there were.

  The present invention has been made to solve the above-described problems, and provides a potential sensor capable of reducing the size and weight and improving sensitivity, facilitating manufacture, and increasing the degree of freedom in design and manufacture. It is intended.

  In order to achieve the above object, a potential sensor according to the present invention includes a base member made of a semiconductor substrate, a vibrating body formed in a cantilever shape with respect to the base member by a semiconductor manufacturing technique, It is characterized by comprising a detection electrode formed by a semiconductor manufacturing technique on the surface of the tip portion and a piezoelectric element formed by a semiconductor manufacturing technique on the surface of the vibrating body.

  With this configuration, it is possible to reduce the size and weight, improve mass productivity, and further improve the sensitivity of the sensor without reducing the movable range of the detection electrode.

  In the potential sensor according to the present invention, the base member may be provided only on the base end side of the vibrating body.

  With this configuration, further reduction in size and weight can be achieved.

  Furthermore, in the potential sensor according to the present invention, the base member is provided on the base end side of the vibrating body, and is provided on either the left or right side of the vibrating body, and has an L-shaped planar shape. It may be made.

  With this configuration, the flatness can be easily obtained when the potential sensor is mounted, so that the mounting operation can be performed more easily and reliably.

  Furthermore, in the potential sensor according to the present invention, the base member is provided on the proximal end side of the vibrating body, and is provided so as to surround the left and right sides and the distal end side of the vibrating body, A rectangular ring may be formed.

  With this configuration, it is easier to obtain flatness when the potential sensor is mounted, so that the mounting operation can be performed more easily and reliably.

  According to the present invention, since the potential sensor is manufactured by a semiconductor manufacturing technique, it is possible to reduce the size and weight, improve mass productivity, and further improve sensitivity.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, FIG. 1 is a perspective view showing a potential sensor according to this embodiment, FIG. 2 is a perspective view showing another example of the potential sensor according to this embodiment, and FIG. 3 is a potential sensor according to this embodiment. FIG. 4 is a perspective view showing still another example of the potential sensor according to the present embodiment.

  The potential sensor 10 according to the present embodiment is schematically configured from a base member 11 made of a semiconductor substrate such as a silicon wafer, and a vibrating body 12 provided in a cantilever shape with respect to the base member 11.

  As shown in FIG. 1, the base member 11 is provided only on the base end side of the vibrating body 12 to form a rectangular shape, and has a plate thickness of about 0.5 mm. The vibrating body 12 is manufactured using a semiconductor manufacturing technology such as MEMS (Micro Electro Mechanical Systems), and can be reduced to a thickness of about 1 to 10 μm. As a result, the potential sensor 10 according to the present embodiment has an outer size of about 5 mm in length, about 5 mm in width, and about 2 μm in height in a packaged state, which is about 1/100 of the conventional potential sensor. Downsizing can be achieved.

  In addition, the vibrating body 12 has a detection electrode 13 formed on the surface of the tip so as to face the object to be measured, and the first piezoelectric element 14 and the second piezoelectric element 15 are linearly formed along the surface. These piezoelectric elements 14 and 15 are connected to an oscillation circuit (not shown). The detection electrode 13, the first piezoelectric element 14, and the second piezoelectric element 15 are each manufactured as a part of the component directly on the vibrating body 12 by a semiconductor manufacturing technique such as a sputtering method or a sol-gel method. It has become. As a result, since the bonding process can be omitted in the manufacturing process of the potential sensor 10, the manufacturing of the potential sensor 10 can be facilitated, and the characteristics such as environmental resistance can be improved and the stability can be improved. It is possible to increase the degree of freedom of design and manufacture.

  The potential sensor 10 having such a configuration operates as follows.

First, when a drive signal from the oscillation device is supplied to the first piezoelectric element 14 and the second piezoelectric element 15, the piezoelectric elements 14 and 15 are distorted, the vibrating body 12 vibrates, and the detection electrode 13 vibrates. To do. When the detection electrode 13 vibrates, the distance between the detection electrode 13 and the measurement object is periodically changed. Due to the periodic change of the distance, the distance between the detection electrode 13 and the measurement object is changed. The electrostatic capacity generated in the circuit changes periodically. As a result, an electric charge is induced in the detection electrode 13 and an AC signal is generated. And since this alternating current signal is proportional to the electric potential of the said measuring object, the electric potential of the said measuring object can be measured with this alternating current signal As mentioned above, the electric potential sensor 10 which concerns on embodiment of this invention Therefore, since the potential sensor 10 is manufactured by a semiconductor manufacturing technique, it is possible to reduce the size and weight, improve the mass productivity, and further increase the movable range of the detection electrode 13. It is possible to improve the sensitivity as a sensor without reducing the size. Further, not only the vibrator 12 but also the entire package can be manufactured by a semiconductor manufacturing technique. In this case, the mounting operation of the potential sensor 10 by the end user can be performed more easily and reliably.

  Furthermore, in this potential sensor 10, an array structure can be designed. As shown in FIG. 2, a plurality of vibrators 12a, 12b, and 12c are simultaneously attached to one base member 11 while reducing the size and weight. Can be arranged. Therefore, it can be flexibly applied to applications that require continuous potential measurement at a plurality of measurement points on a straight line or surface, such as measurement of the wafer surface potential in a semiconductor production line. Expansion can be achieved.

  In the above-described embodiment, the base member 11 has a rectangular shape, but this is merely an example. For example, as shown in FIG. 3, the base member 11 ′ is connected to the base end of the vibrating body 12. 2 and the left and right sides (right side in FIG. 2) of the vibrating body 12 to form an L-shaped planar shape or, for example, as shown in FIG. 4, the base end side of the vibrating body 12 In addition, various modifications such as forming the base member 11 ″ in a rectangular ring shape so as to surround the left and right sides and the tip side of the vibrating body 12 are possible.

It is a perspective view which shows the electric potential sensor which concerns on embodiment of this invention. It is a perspective view which shows another example of the electric potential sensor which concerns on embodiment of this invention. It is a perspective view which shows another example of the electric potential sensor which concerns on embodiment of this invention. It is a perspective view which shows another example of the electric potential sensor which concerns on embodiment of this invention. It is a perspective view which shows a prior art example. It is the schematic which shows operation | movement of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Potential sensor 11 Base member 12 Vibrating body 13 Inspection electrode 14 1st piezoelectric element 15 2nd piezoelectric element

Claims (4)

A base member made of a semiconductor substrate;
A vibrating body formed in a cantilever shape by semiconductor manufacturing technology with respect to the base member;
A sensing electrode formed by semiconductor manufacturing technology on the surface of the tip of the vibrator;
A piezoelectric element formed on the surface of the vibrating body by a semiconductor manufacturing technique;
A potential sensor characterized by comprising: The potential sensor according to claim 1, wherein the base member is provided only on a base end side of the vibrating body. 2. The base member according to claim 1, wherein the base member is provided on a base end side of the vibrating body and is provided on either the left or right side of the vibrating body and has an L-shaped planar shape. Potential sensor. 2. The base member according to claim 1, wherein the base member is provided on a base end side of the vibrating body, and is provided so as to surround the left and right sides and the tip side of the vibrating body, and forms a rectangular ring shape. The potential sensor described.

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