JP2539430B2 - Static electricity detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a detection technique, and particularly to a technique effectively applied to detection of static electricity.

[Conventional technology]

A conventional static electricity measuring device is described in Japanese Patent Publication No. 50-32633. The outline is that the rotating sector type electrostatic measuring device obtains the electric field potential by receiving the electric force line emitted from the charged body by the detection electrode provided behind the grounded rotating sector facing the charged body to be measured. As a result, the electric force lines are intermittently turned on and off, so that the potential of the detection electrode becomes an AC potential. This electrode potential is proportional to the potential of the charged body, and is amplified by an AC amplifier to cause the indicating instrument to indicate.

[Problems to be solved by the invention]

The present inventor has attempted to measure (synonymous with detection) static electricity by a method similar to the above-described technique. At that time, in order to ground the rotation center (hereinafter referred to as "earth"), one metal plate-like object was bent and formed, and arranged so as to be in contact with the shaft for rotating the rotating sector.
However, it has been found that the plate-like object as the ground may not follow the subtle vibration when the rotating sector rotates.

In the above case, the rotating sector itself is charged by electrostatic induction, and the detection electrode (hereinafter referred to as the detection electrode) also measures the charging of the rotating sector, which makes accurate detection impossible. , Was made clear by the present inventor.

An object of the present invention is to provide a technique capable of reliable grounding without being affected by vibrations of the rotating sector during rotation.

Another object of the present invention is to provide a technique capable of accurately detecting static electricity without being affected by vibrations of a rotating sector during rotation.

The above and other objects and novel features of the present invention will be apparent from the description of the present specification and the accompanying drawings.

[Means for solving problems]

The outline of a typical one of the inventions disclosed in the present application will be briefly described as follows.

That is, a brush for grounding is fixed to one end of a metal plate, and the other end of the plate is fixed to another metal part. At this time, the brush is
It shall be supported so that it can vibrate in the thickness direction of the plate-like object.

On the other hand, a rubber bar is bent in a U shape, and one end of the outer ring is attached to the back side of the brush attachment surface of one end of the plate to which the brush is attached, so that the rubber has a restoring force. , The brush is arranged so as to be pushed, and the other end of the rubber material is attached to the other metal part. In this way, two sets of grounding members are produced, arranged so that the brushes hit the shafts, sandwiching the shaft connected to the rotating sector to be grounded.

[Work]

According to the above means, the two sets of brushes are pressed against the shaft by the restoring force (elastic force) of the rubber material,
It can be grounded more stably than one set. Furthermore, the spring force of the metal plate and the restoring force (elastic force) of the rubber material allow the brush to follow the vibration of the shaft, and even if there is vibration of the shaft, compared to the integrated lever type one, A good ground can be obtained.

In this way, since a reliable ground is obtained, the rotating sector itself can be prevented from being charged by electrostatic induction, so the detection electrode can detect only the charge of the detected object, and accurate electrostatic detection can be performed. Is something that can be done.

〔Example〕

FIG. 1 is a front view showing a state in which a motor rear portion and a ground member are incorporated in a sensor of a static electricity detection device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the configuration of an electrostatic detection device that is an embodiment of the present invention.

In FIG. 1, reference numeral 1 is a motor for rotating a rotating sector described later. A shaft 2 extends from the motor and transmits rotation. Reference numeral 3 denotes a brush, which is made of metal and is disposed so as to face the shaft 2 and to be in contact with the brush 3. Reference numeral 4 denotes a first stay, which is a rectangular metal plate-like member, and has the brush 3 at one end.
Is fixed, and the other end is bent and fixed to a fixing member described later. Reference numeral 5 denotes a pressing member, which is a prismatic member formed of rubber, and one end of which is attached to the surface (same end) opposite to the surface of the first stay 4 on which the brush 3 is attached, and the other. The end is fixed to a fixing member described later. At this time, the pressing member 5 is deformed and attached in a U shape within the range of elastic deformation. Reference numeral 6 denotes a fixing member, which is a substantially L-shaped metal plate, to which the first stay 4 is attached at one end and the pressing member 5 is attached at the other end. The fixing member 6 is fixed to a cover described later. 7 is
The cover is a rectangular parallelepiped, is made of metal, and is grounded by a ground wire (not shown).

In FIG. 2, reference numeral 8 denotes a rotating sector, which is a metal cylindrical object, and two circular through holes (not shown) are provided on the side surface (curved surface portion) in the circumferential direction. This rotating sector 8
The shaft 2 is attached through the inside of the cylinder,
As the shaft 2 rotates, it rotates in the circumferential direction. Reference numeral 9 denotes a detection electrode, which is a plate-shaped member having an arc-shaped cross section in a direction orthogonal to the longitudinal direction,
It is inserted inside and installed in the rotating sector 8 without rubbing. 10 is a second stay, and an annular metal plate,
It is a substantially S-shaped plate-shaped member integrally molded, and the detection electrodes 9 are connected and supported by an annular portion. Reference numeral 11 denotes an operational amplifier, which has a function of amplifying and rectifying an AC signal obtained from the detection electrode 9. Therefore, the second
The stay 10 is electrically connected to the operational amplifier 11. Reference numeral 12 denotes an output, which is for outputting the signal that has been operationally amplified by the operation amplification section 11. Reference numeral 13 is a peak hold circuit for stabilizing the level display and the like by holding the peak of the output from the output 12 (peak of each wave).

Here, in order to hold the peak of each wave, a reset signal is required, but during the reset period, there is a dead zone of detection, so in this embodiment, two peak hold circuits are arranged in parallel (see FIG. The phase of the reset pulse is staggered (not shown) so that it can always be detected (peak hold). 14 is a sensor output, and the peak hold circuit
It is for guiding the output from 13 to a sensor output terminal described later. 15 is a sensor output terminal for outputting the magnitude of static electricity to the outside, for example, X-
A Y recorder, a level meter, etc. are connected. Reference numeral 16 denotes an amplifier, which is compared with a set voltage in a minute area (for example, 0.
Compared with the set value of 4V, such as 0.35V), there is a high possibility of making an erroneous judgment due to any noise, so it is for amplifying and making comparison easier. Are connected. Reference numeral 17 denotes a maximum level setting volume, which is adapted to turn on a maximum display lamp, which will be described later, when static electricity having a level equal to or higher than the level set here is detected. Reference numeral 18 denotes a maximum display lamp, which is turned on when static electricity having a level equal to or higher than the level set by the maximum level setting volume 17 is detected. Reference numeral 19 denotes a control unit, which is a stop level comparison circuit for performing a relay output described later, an alarm level comparison circuit for detecting an abnormal static electricity and displaying an alarm (sounds a buzzer), and the stop level is exceeded. It is equipped with a counter that counts the number of times.

The stop level comparison circuit includes a comparator, and when a predetermined level is set by the setting of the stop level setting volume 20 and static electricity exceeding this level is detected, it is latched and then relayed to output, for example, this device. It is possible to stop the device to which the is attached or sound an alarm described later. Further, the number of times of stop can be counted by using a counter circuit (not shown). 21 is
A stop lamp is connected to the stop level comparison circuit and is turned on when static electricity exceeding a predetermined level (stop level) is detected. Further, the alarm level comparison circuit (not shown) also includes a comparator, and when a predetermined level is set by the setting of the alarm level setting volume 22 and static electricity exceeding this level is detected, an alarm lamp described later is activated. It is a circuit that lights up and sounds a buzzer described later. Reference numeral 23 denotes an alarm lamp, which is lit when static electricity of a predetermined level (alarm level) or higher is detected. Reference numeral 24 is a buzzer for sounding an alarm in synchronization with the alarm lamp 23. 25 is
A relay, which outputs a stop signal from the stop level comparison circuit, is connected to the relay output terminal 26. 27 is a reset switch for resetting the latch circuit. Reference numeral 28 denotes an IC. In this embodiment, a DIL (dual-in-line) type IC in which leads project from both sides of the package in the longitudinal direction to be described later is shown. There is. Reference numeral 29 denotes a package, which covers the periphery of the pellet as the heart of the IC and a part of leads described later,
It has a rectangular parallelepiped shape. Reference numeral 30 denotes a lead, which is used to establish continuity between the pellet and the outside of the IC.

In this embodiment, the surrounding area including the rotating sector 8 and the detection electrode 9 is used as a sensor.

Hereinafter, the operation of the embodiment of the present invention having the above-described configuration will be described.

In FIG. 2, the rotation sector 8 rotates via the shaft 2 by the operation of the motor 1. At this time, since the rotating sector 8 is provided with two circular through holes (not shown), the detection electrode 9 is intermittently seen through the through hole. In this state, the IC 28 as an object to be detected passes under the detection electrode 9. Then IC28 package 29
When static electricity is charged on the main surface of the, the electric field lines are generated between the IC 28 and the detection electrode 9 due to the phenomenon of electrostatic induction, while the rotation of the rotating sector 8 moves the through hole. Electric lines of force are transmitted as intermittent ones.

Therefore, an alternating current signal is obtained from the detection electrode 9.
The obtained AC signal is amplified and rectified by the operational amplifier 11, which becomes a DC voltage proportional to the charging voltage of the IC 28.

Here, as shown in FIG. 1, the operation of the embodiment of the present invention is that the shaft 2 connected to the rotating sector (not shown) is grounded by the brush 3 from the upper and lower directions. Therefore, even if the shaft 2 rotates in a vibrating state, the brush 3 (ground) can be reduced from being separated from the shaft 2 as compared with the case where one shaft is grounded.

Further, since the brush 3 is elastically supported by the first stay 4 and is in contact with the shaft 2 by the elastic force of the pressing member 5, even when the shaft 2 vibrates and rotates, It follows the vibration direction,
A reliable ground can be obtained. Therefore, since the rotating sector 8 is always grounded, there is no electrostatic induction to the rotating sector 8 due to the charging of the object to be detected.
Therefore, the charging of the rotating sector 8 (by electrostatic induction)
The detection electrode 9 does not detect (the rotation sector 8 is not charged), and only the charge of the detected object can be detected.

By the way, the peak voltage of the DC voltage obtained from the operational amplifier 11 is held by the peak hold circuit 13 in FIG. 2 for a certain period of time and output to the sensor output terminal 15 and the amplifier 16. For example, X-Y
If a recorder is connected, the charging voltage can be shown on the XY graph, and its magnitude can be visually confirmed.

On the other hand, in the amplifier 16, a minute voltage is amplified and output as a relatively large voltage (for example, 0.3V is amplified to 3V).

By the way, assuming that the maximum level setting volume 17 is adjusted to a level corresponding to the charging of 50V, for example, when the detected voltage is 70V, the output from the amplifier 16 causes the maximum display lamp 18 to light up. , You can get the news that the maximum level of 50V is exceeded.

Returning to the original, the signal amplified by the amplifier 16 is sent to the control unit 19. Here, for example, if the level is adjusted to a level corresponding to the charging of 40V by the stop level setting volume 20, when the detected voltage is 70V, the latch circuit (not shown) is passed through the comparator of the stop level comparison circuit (not shown). Is latched by the relay 25 and a signal is output from the relay output terminal 26 by the relay 25.
If this signal is output to the stop signal line of the device to which the static electricity detection device of this embodiment is attached (for example, IC manufacturing device), the IC manufacturing device can be stopped. It is possible to reduce the occurrence of electrostatic breakdown. When the IC manufacturing apparatus stops, the stop lamp 2 lights up and the buzzer 24 sounds, and it is possible to know that the IC manufacturing apparatus has stopped beyond the stop level.

By the way, according to the above description, the operation of stopping the IC manufacturing apparatus is performed. However, by using a counter (not shown), the number of times to stop the IC manufacturing apparatus can be counted without stopping the IC manufacturing apparatus.

Also, with the alarm level setting volume 22, for example,
If it was adjusted to a level suitable for 3V charging,
When the detected voltage is 70 V, it is possible to know that the alarm lamp 23 is turned on and the buzzer 24 sounds while the alarm level is exceeded through a comparator of an alarm level comparison circuit (not shown).

In the above description, the functions of the static electricity detection device according to the present embodiment have been individually described, but a series of operations will be described below.

For example, if the charging voltage that is considered to cause electrostatic breakdown of the IC as the detected object is 100V, the maximum level setting volume 17 is set to a level corresponding to 100V charging, and the stop level setting volume 20 is set to a level corresponding to 90V. Further, it is assumed that the alarm level setting volume 22 is adjusted to a level corresponding to 80V. If the relay output terminal 26 is set in the IC manufacturing device in this state and the relay output terminal 26 is incorporated into the stop signal line of the IC manufacturing device, the IC with 70V charging during the IC manufacturing
However, if it passes below the detection electrode 9, the IC manufacturing apparatus continues to operate without a geometrical problem of less than 80 V set as the alarm level. However, when it has a charge of 85V, the alarm lamp 23 lights up and the buzzer sounds.
A beep will sound to alert the operator that the charge level is alarming.

In addition, if it has a charge of 95V, the alarm lamp 23
While the stop lamp 21 lights up, the IC manufacturing device stops and the buzzer 24 sounds. At this stage, the operator can check whether the IC manufacturing equipment has any cause of static electricity generation. Therefore, if there is a cause in the IC manufacturing apparatus, it is possible to prevent the occurrence of defective ICs due to electrostatic breakdown by reviewing the location.

In addition, if there is no cause in the IC manufacturing apparatus, by performing a retrospective review of the previous process, it is possible to prevent occurrence of an IC failure due to electrostatic breakdown.

By the way, if you have 110V charging,
23, the stop lamp 21, and the maximum display lamp 18 are turned on, the IC manufacturing device is stopped, and the buzzer 24 sounds. At this stage, the operator considers that the corresponding IC has been destroyed by static electricity, rejects it, and can check whether it is a defective product. Therefore, it is possible to reduce the flow of defects in the next process,
For example, when the next process is not a process for detecting (inspecting) electrostatic breakdown, useless work can be reduced (manufacturing without knowing a defect is reduced).

Further, by retrospectively reviewing the corresponding IC manufacturing apparatus or the previous process, it is possible to reduce the occurrence of a large number of defects.

In this embodiment, the case where the maximum level, the stop level, and the alarm level are all set is described.
It can be used as an alarm only, and the combination expands its application range.

Further, by using the sensor output terminal 15 shown in FIG. 2 and operating a level meter incorporating a plurality of comparators, the charged voltage can be visually confirmed.

By the way, in this embodiment, the brush 3 is arranged from two directions as the ground of the rotating sector 8, but the brush 3 may be arranged in three directions or more, and the ground is further stabilized.

Further, the pressing member 5 is not limited to the rubber material and may be another elastic body.

Furthermore, although an IC is used as the detected object in this embodiment,
It can be applied to the manufacture of things that are sensitive to static electricity.

(1) Even if the object to be grounded vibrates subtly by pinching the object to be grounded with a brush from at least two directions and by elastically contacting the brush with the object to be grounded, The brush can elastically follow the object to be grounded. Therefore, compared to the one in which an integral metal plate comes into contact with the ground,
The earth is stable.

(2) In the static electricity detection device, the rotating body for intermittently disconnecting between the detection electrode and the object to be measured is sandwiched by the brush from at least two directions, and the brush is elastically brought into contact with the rotating body. As a result, the brush can elastically follow the delicate vibration when the rotating body rotates. Therefore, compared to the one in which one metal plate contacts and grounds, the ground is more stable, electrostatic induction from the object to be detected can be reduced, and the detection electrode can measure the charging of the rotating body. The amount of static electricity can be reduced and accurate static electricity can be detected.

Although the invention made by the present inventor has been specifically described based on the embodiment, the embodiment is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. There is no end.

In the above description, the case where the invention made by the present inventor is mainly applied to the static electricity detection technique in the manufacturing process of an IC, which is a field of application which is the background of the invention, is not limited thereto.

〔The invention's effect〕

The following is a brief description of an effect obtained by the representative one of the inventions disclosed in the present application.

That is, the object to be grounded is sandwiched by a brush as a grounding material from at least two directions, and the brush elastically contacts the object to be grounded so that the brush follows the subtle vibration of the object to be grounded. As a result, a stable earth effect can be obtained.

[Brief description of drawings]

FIG. 1 is a front view showing a state in which a motor rear portion and a grounding member are incorporated in a sensor of a static electricity detection device according to an embodiment of the present invention, and FIG. 2 is a static electricity detection according to an embodiment of the present invention. It is the schematic which shows the structure of an apparatus. 1 ... motor, 2 ... shaft, 3 ... brush, 4 ...
1st stay, 5 ... pressing member, 6 ... fixing member, 7 ...
… Cover, 8 …… Rotating sector, 9 …… Detecting electrode, 10 ……
Second stay, 11 ... Operational amplifier, 12 ... Output, 13 ...
Peak hold circuit, 14 ... Sensor output, 15 ... Sensor output terminal, 16 ... Amplifier, 17 ... Maximum level setting volume, 18 ... Maximum display lamp, 19 ... Control section, 20 ... Stop level setting volume , 21 ... Stop lamp, 22 ...
… Alarm level setting volume, 23… Alarm lamp, 24…
… Buzzer, 25 …… Relay, 26 …… Relay output terminal, 27…
… Reset switch, 28 …… IC, 29 …… Package, 30
...... Lead.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-54-23908 (JP, A) JP-B-51-8031 (JP, B2) JP-B-50-45338 (JP, Y2) JP-B-62- 10691 (JP, Y2)

Claims (1)

(57) [Claims] 1. A static electricity detection device including a sensor for detecting static electricity charged in a semiconductor device, comprising: a detection electrode for detecting the electrification of the semiconductor device; and a rotating sector into which the detection electrode is inserted. A motor that rotates the rotating sector via a shaft, a cover that covers the rotating sector and is grounded, a brush that is in contact with the shaft of the motor so as to sandwich the shaft from at least two directions, and is fixed to the cover. A static electricity detection device for a semiconductor device, characterized in that the brush and the fixing member are connected by a stay made of a metal plate and a holding member made of rubber.