JP2585593B2 - Static electricity detector for semiconductor devices - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology that is effective when applied to the detection of static electricity in a semiconductor device.

[Conventional technology]

A conventional static electricity measuring device is described in JP-A-48-22071. The outline is shown as an electrostatic measurement device configured so that electrodes are exposed at regular intervals in a window provided in a shield case and an induced potential generated in the electrodes is applied to an amplifier through a sliding contact. As the shield case, a cylindrical case is shown.

[Problems to be solved by the invention]

The inventor measured static electricity of an IC being manufactured by a semiconductor (hereinafter referred to as IC) manufacturing apparatus using an electrostatic measurement apparatus having a prismatic shield case similar to the above-described configuration. I found that there was a problem as shown in

In other words, in order to remove the static electricity from the IC, the static electricity (static electricity) of the IC within the spraying range of the ion blow (forcibly generating and blowing ions) attached to the IC manufacturing equipment is removed. In the measurement, an air flow containing ions due to the blowing of the ion blow impinges on the shield case, and the air flow becomes a vortex, jumps into a window provided in the shield case, comes into contact with the detection electrode, and is induced on the detection electrode. Charge is neutralized and reduced,
The problem is that it is not possible to accurately detect static electricity of the IC.

Therefore, a cylindrical shield case (hereinafter referred to as a cover) is used as in the conventional example, but a part of the airflow escapes along the outer ring of the cylindrical cover, but the edge of the cylindrical cover (a window is provided). (The part close to the surface where it is located) forms an eddy current, and it has also been found that it is impossible to measure the static electricity of the IC accurately in the same manner as described above.

An object of the present invention is to provide a detection technique capable of accurately detecting static electricity without being affected by the surrounding environment.

It is another object of the present invention to accurately detect static electricity, thereby managing static electricity in an IC during a manufacturing process of the IC, for example, and reducing defects due to electrostatic breakdown.

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

[Means for solving the problem]

The outline of a representative invention among the inventions disclosed in the present application will be briefly described as follows.

That is, a sensor having a detection electrode and a rotating sector,
A prismatic cover that covers the sensor, and a detection hole provided in a part of a surface orthogonal to a longitudinal side surface of the cover,
The prism has a longitudinal side surface and a tapered surface formed toward the detection hole, the sensor is located near a surface provided with the detection hole, and further, a longitudinal side surface of the cover. The spherical processing for smoothing the flow of the air flow of the ion blow blown to the surface between the longitudinal side surface of the cover and the tapered surface and the surface orthogonal to the longitudinal side surface of the cover and the tapered surface And a static electricity detecting device for a semiconductor device.

[Action]

According to the means described above, as one approaches the window of the cover,
Since the tapered surface is formed and the edge portion is formed as the R surface, even if the airflow due to ion blow comes in contact, the airflow will flow along the tapered surface and the R surface, so that eddy currents will be generated. It is possible to reduce the airflow jumping into the window. Therefore, the object to be detected can be detected by reducing the neutralization of the electric charge of the detection electrode by undesired ions, so that accurate detection can be performed as compared with those having a cylindrical or prismatic cover. Things.

In addition, accurate static electricity detection is possible, so by installing and managing IC manufacturing equipment, detecting abnormalities (detecting abnormal static electricity) and taking measures such as stopping the equipment, the failure due to static electricity destruction The generation can be reduced.

〔Example〕

FIG. 1 is a schematic sectional view showing a sensor and a cover of an electrostatic detection device according to an embodiment of the present invention.

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

FIG. 3 is a diagram for explaining the operation of one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a sensor, which is a generic name for a rotating sector and a detection electrode, which will be described later. Reference numeral 2 denotes a detection electrode, which is a metal plate having a circular cross section in a direction perpendicular to the longitudinal direction (the paper surface direction). Reference numeral 3 denotes a rotating sector, which is a metal cylinder, and is provided with two circular through holes (not shown) on a circumferential side surface (curved surface portion). The rotating sector 3 is rotated by a motor described later. Reference numeral 4 denotes a cover, which is a prism-shaped box, and a side surface 5 in the longitudinal direction (the thickness direction of the paper surface) is formed with a tapered surface 6 as it approaches a detection hole described later (formed narrower as it approaches the detection hole). ing. Reference numeral 7 denotes a first radius (R),
Between the tapered surface 6 and the longitudinal direction of the cover, and is subjected to a spherical processing for smoothing the air flow. Reference numeral 8 denotes a second radius (R), which is formed between the tapered surface 6 and the bottom surface 9 in the longitudinal direction of the cover, and is subjected to a spherical process for smoothing the air flow. ing. Reference numeral 10 denotes a detection hole, which is a circular hole provided on the bottom surface 9 of the cover 4 and is located below the detection electrode 2. The detection hole 10 is for detecting static electricity of an object to be measured (a word synonymous with the object to be detected).

In FIG. 2, reference numeral 12 denotes a stay, which is formed by integrally forming an annular metal plate and a substantially S-shaped, plate-like object, and connecting the detection electrodes 2 at an annular portion. I support it. 13 is a shaft, which extends from a motor described later,
The stay 12 is connected to the rotating sector 3 through an annular portion. The rotating sector 3 is rotated (rotated in the circumferential direction) via a shaft 13 by a motor described later. Reference numeral 14 denotes a motor for rotating the rotating sector 3. Reference numeral 15 denotes an operational amplifier, which is electrically connected to the stay 12 extending from the detection electrode 2, and has a function of amplifying and rectifying an AC signal obtained from the detection electrode 2.

Although not shown in FIGS. 1 and 2, it is assumed that the shaft 13 is grounded and is always at zero potential.

Reference numeral 16 denotes an output for outputting a signal that has been arithmetically amplified by the operational amplifier 15. Reference numeral 17 denotes a peak hold circuit for holding the output peak (peak of each wave) from the output 16 to stabilize the level display and the like.

Here, a reset signal is required to hold the peak of each wave. However, during the reset period, a dead zone for measurement (detection) is provided. In this embodiment, two peak hold circuits are arranged in parallel. (Not shown), the phase of the reset pulse is shifted so that measurement (and peak hold) can always be performed. Numeral 18 denotes a sensor output for guiding the output from the peak hold circuit 17 to a senna output terminal described later. Reference numeral 19 denotes a sensor output terminal for outputting the magnitude of static electricity to the outside. For example, an XY recorder and a level meter are connected. Reference numeral 20 denotes an amplifier, which has a high possibility of erroneous determination due to any noise in comparison with a set voltage in a minute area (for example, comparison of a set value of 0.4 V with 0.35 V or the like). It is for amplification and easy comparison,
The peak hold circuit 17 is connected. Reference numeral 21 denotes a maximum level setting volume, and a maximum display lamp, which will be described later, is turned on when static electricity at or above the level set here is detected. Reference numeral 22 denotes a maximum level display lamp which is turned on when static electricity at a level equal to or higher than the level set by the maximum level setting volume 21 is detected. Reference numeral 23 denotes a control unit, which detects a stop level comparing circuit for performing a relay output described later and abnormal static electricity,
An alarm level comparison circuit for displaying an alarm (sounding a buzzer), a counter for counting the number of times exceeding the stop level, and the like are provided.

The stop level detection circuit is provided with a comparator, a predetermined level is set by the setting of the stop level setting volume 24, and when static electricity exceeding this level is detected, the signal is latched by the latch circuit and then relayed and output. For example, it is possible to stop a device to which the present device is attached, or to sound an alarm described later. The number of stops can be counted using a counter circuit (not shown). Reference numeral 25 denotes a stop lamp, which is connected to the stop level comparison circuit and turns on when static electricity exceeding a predetermined level is detected. Further, the alarm level comparison circuit (not shown) also includes a comparator, and a predetermined level is set by the setting of the alarm level setting volume 26, and when static electricity exceeding this level is detected, an alarm lamp described later is activated. It is a circuit for lighting and sounding a buzzer. Reference numeral 27 denotes an alarm lamp, which turns on the lamp when static electricity of a predetermined level or more is detected. 28
Is a buzzer for sounding an alarm in synchronization with the alarm lamp 27. Reference numeral 29 denotes a relay for outputting a stop signal from the stop level comparison circuit, which is connected to a relay output terminal 30. 31 is a reset switch for resetting the latch circuit. Reference numeral 32 denotes an IC, which in this embodiment is a DIL (dual in-line) type IC having leads protruding from both sides in the longitudinal direction of the package, which will be described later, and is an object to be measured. Reference numeral 33 denotes a package, which covers the periphery of the pellet as a core part of the IC and a part of a lead described later, and has a rectangular parallelepiped shape. 34
Is a lead for establishing conduction between the pellet and the outside of the IC.

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

First, as for the movement of the sensor, in FIG. 2, the rotating sector 3 is rotated via the shaft 13 by the operation of the motor 14. At this time, since two circular through holes (not shown) are provided in the rotating sector 3, the detection electrode 2 intermittently looks through the through holes. In this state, the IC 32 as the detection object passes through most of the detection electrode 2. Then, if static electricity is accumulated on the main surface of the package 33 of the IC 32, etc., the static electricity may cause the static electricity to be lost.
The lines of electric force are generated between the IC 32 and the detection electrode 2, while the rotation of the rotary sector 3 moves the through-holes, so that the lines of electric force are transmitted intermittently.

Then, an AC signal is obtained from the detection electrode 2. The obtained AC signal is amplified and rectified by the operational amplifier 15, which becomes a DC voltage proportional to the static electricity voltage (static electricity) of the IC 32.

Here, the operation of one embodiment of the present invention will be described. As shown in FIG. 3, the flow of air current (thick arrow in the drawing)
Corresponds to the side surface 5 of the cover 4 and spreads in all directions. At this time, the airflow flowing in the direction of the detection hole 10 of the cover 4 is
And flows along the tapered surface 6. afterwards,
Through the second radius 8, it flows almost in the detection hole 10 or almost in parallel with the detection hole 10. Therefore, even when ions are contained in the airflow, it is possible to reduce the possibility of jumping into the detection holes 10 and touching the detection electrodes 2, and reduce the neutralization of the charges of the detection electrodes 2 by undesired ions. . As a result, the static electricity of the object to be detected is detected as it is, and the static electricity can be detected more accurately as compared with those having a prismatic or cylindrical cover.

In addition, accurate detection of static electricity is possible, so when applied to IC manufacturing equipment in the IC manufacturing process, erroneous determination is reduced, and IC
It is possible to manufacture ICs while preventing the occurrence of defects or minimizing the occurrence of IC defects due to electrostatic breakdown.

 Hereinafter, the operation of another configuration will be described.

The DC voltage obtained from the operational amplifier 15 is held at a peak by a peak hold circuit 17 for a certain period, and is output to the sensor output terminal 19 and the amplifier 20. If, for example, an XY recorder is connected to the sensor output terminal 19,
The static electricity voltage can be shown on the XY graph, and its magnitude can be confirmed by eyes.

On the other hand, the amplifier 20 amplifies a very small voltage and outputs it as a relatively large voltage (for example, amplifies 0.3V to 3V).

By the way, if the maximum level setting volume 21 has been adjusted to a level corresponding to, for example, a 50 V power failure, if the detected voltage is 70 V, the maximum display lamp 22 is turned on by the output from the amplifier 20. , It is possible to obtain a notification that the voltage exceeds the maximum level of 50V.

Returning to the original state, the signal amplified by the amplifier 20 is sent to the control unit 23. Here, for example, assuming that the voltage is adjusted to a level corresponding to the power failure of 40 V by the stop level setting volume 24, if the detected voltage is 70 V, a latch (not shown) is passed through a comparator of a stop level comparison circuit (not shown). The signal is latched by the circuit, and a signal is output from the relay output terminal 30 by the relay 29. If this signal is output to a stop signal line of a device (for example, an IC manufacturing device) to which the static electricity detection device of this embodiment is attached, the IC manufacturing device can be stopped, and the IC being manufactured by this IC manufacturing device can be stopped. Can be reduced. When the IC manufacturing apparatus is stopped, the stop lamp 25 is turned on, the buzzer 28 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, for example, by the alarm level setting volume 26,
If the detected voltage is 70 V, the alarm lamp 27 is turned on, the buzzer 28 sounds, and the alarm is turned on. You can know that you are over the level.

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

For example, assuming that the static electricity voltage that is likely to lead to electrostatic breakdown of the IC as an object to be detected is 100 V, the maximum level setting volume 21 is adjusted to a level corresponding to the 100 V electrical interruption, and the stop level setting volume 24 is adjusted to 90 V. It is assumed that the alarm level setting volume 26 is adjusted to a level corresponding to 800 V, respectively. In this state, the IC is set in the IC manufacturing apparatus, and the relay output terminal 30 is incorporated in the stop signal line of the IC manufacturing apparatus. If it passes, the IC manufacturing equipment continues to operate without any problem because it is less than the alarm level set at 80V. However, when there is a power failure of 85 V, the alarm lamp 27 is turned on and the buzzer 28 sounds to notify the worker that the power failure level should be watched.

In addition, if there is a 95 V
And the stop lamp 25 is turned on, while one of the manufacturing apparatuses is stopped, and the buzzer 28 sounds. At this stage, the worker can check whether there is any cause of static electricity generation in the IC manufacturing apparatus. Therefore, when there is a cause in the IC manufacturing apparatus, by reviewing the location, it is possible to prevent the occurrence of the failure of the IC due to the electrostatic breakdown.

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 there is a 110 V
7. The stop lamp 25 and the maximum display lamp 22 light up, the IC manufacturing apparatus stops, and the buzzer 28 sounds. At this stage, the worker considers that the corresponding IC has been destroyed by static electricity, rejects the IC, and can check whether the IC is defective. Therefore, it is possible to reduce the flow of defects in the next process,
For example, if the next step is not a step of detecting (inspection) electrostatic breakdown, useless work can be reduced (reducing manufacturing without knowing that it is defective).

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

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.

In addition, by using the sensor output terminal 19 shown in FIG. 2 and operating a level meter incorporating a plurality of comparators, it is possible to visually check the static voltage.

In the present embodiment, the tapered surface is formed toward the detection hole of the cover, but a radius (R) may be provided.

By the way, in the present embodiment, the sensor structure (including the motor) cannot be made small (a rectangular parallelepiped shape), so that only the longitudinal side surface is narrow. However, if the sensor structure can be made compact, a conical cover is used. A detection hole can be provided at the tip of the cone (in the shape of a slice) so that it can respond to airflow from all directions.

(1) As the cover covering the sensor approaches the detection hole for detection provided in the cover, the width of the cover is narrowed so that the flow of the air current can follow the cover. It is possible to reduce the flow of the airflow into the detection hole as compared with the case of the above. Therefore, even when ions are contained in the airflow, the ions can be prevented from touching the detection electrode, and more accurate static electricity can be detected as compared with a prismatic or cylindrical cover.

(2) Since accurate static electricity can be detected, IC
When applied to IC manufacturing equipment in the manufacturing process of ICs, it is possible to reduce erroneous determination and prevent the occurrence of IC failures due to electrostatic breakdown beforehand, or reduce the occurrence of IC failures due to electrostatic breakdown as much as possible to manufacture ICs. Can be performed.

(3) By making the side portion of the detection hole for detection of the cover that covers the sensor longer than the surface of the detection hole, the airflow flows to most of the detection hole, so that the cover has a prismatic or cylindrical shape. In comparison, the airflow can be reduced from entering the detection hole. Therefore, even when ions are contained in the airflow, the contact of the ions with the detection electrode can be reduced, and the neutralization of the charge of the detection electrode is reduced, so that a prismatic or cylindrical cover is used. In comparison with the method, the static electricity can be detected more accurately.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and it is needless to say that various modifications can be made without departing from the gist of the invention. Nor.

In the above description, the case where the invention made by the present inventor is mainly applied to the static electricity detection technology in the IC manufacturing process, which is the application field behind it, has been described, but the invention is not limited thereto.

〔The invention's effect〕

The effects obtained by the representative inventions among the inventions disclosed in the present application will be briefly described as follows.

That is, by forming the cover covering the sensor narrower as it approaches the detection hole for the detection, it is possible to reduce the entry of airflow into the detection hole and perform accurate detection. .

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a sensor and a cover of an electrostatic detection device according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration of the electrostatic detection device according to one embodiment of the present invention. FIG. 3 is a diagram for explaining the operation of one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Sensor, 2 ... Detection electrode, 3 ... Rotation center, 4 ... Cover, 5 ... Side surface, 6 ... Tapered surface, 7 ... First round (R), 8 ... Second round (R), 9 ... Bottom surface , 10: detection hole, 12: stay, 13: shaft, 14: motor, 15: operational amplifier, 16: output, 17: peak hold circuit, 18: sensor output, 19: sensor output terminal, 20: amplifier, 21 … Maximum level setting volume, 22… Maximum level indicator lamp, 23…
Control unit, 24: Stop level setting volume, 25: Stop lamp, 26: Alarm level setting volume, 27: Alarm lamp, 28: Buzzer, 29: Relay, 30: Relay output terminal, 31
… Reset switch, 32… IC, 33… Package, 34… Lead.

Claims (1)

(57) [Claims] 1. A static electricity detection device for detecting a charged state of static electricity of a semiconductor device within a spraying range of an ion blow, comprising: a sensor having a detection electrode and a rotating sector; a prismatic cover for covering the sensor; The sensor has a detection hole provided in a part of a surface orthogonal to a longitudinal side surface of the cover, and a tapered surface formed toward the detection hole on the prismatic longitudinal side surface. Located near the surface provided with the detection hole, further, spherical processing for smoothing the flow of the air flow of the ion blow blown to the longitudinal side surface of the cover, the longitudinal side surface of the cover and A static electricity detecting device for a semiconductor device, wherein the static electricity detecting device is provided between the tapered surface and a surface orthogonal to a longitudinal side surface of the cover and the tapered surface.