JP2009158375A - Static elimination apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply air with good ion balance without extremely reducing the number of ions. <P>SOLUTION: In an antistatic device 10 for supplying air including ions from a spout 26 to an antistatic object 12, the antistatic device includes a discharge needle 16A for generating positive ions, a discharge needle 16B for generating negative ions, a positive ion carrying passage 14A for carrying the positive ions generated by the discharge needle 16A, a negative ion carrying passage 14B formed differently from the positive ion carrying passage 14A and carrying the negative ions generated by the discharge needle 16B, and a merged section 30 formed just before the spout 26 and merging the positive ion carrying passage 14A and the negative ion carrying passage 14B. The antistatic device also includes a surface electrometer 20 for measuring the surface electrical potential of the antistatic object 12, and a control section 22 for controlling the number of positive ions generated by the discharge needle 16A and the number of negative ions generated by the discharge needle 16B on the basis of measured results. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a static eliminator and a method, and more particularly, to an ion transport type static eliminator that is used for removing static electricity generated in a clean room and blows out winds containing positive ions and negative ions to a static elimination object.

  In the manufacturing process of semiconductor devices with higher performance and higher integration and flat panel displays with larger sizes, it is important to prevent the destruction of devices due to static electricity and the adhesion of dust to products. For this reason, conventionally, static electricity is removed by supplying the air ionized by the static eliminator to the inside of the manufacturing apparatus and the transport process in the manufacturing process.

  However, in the conventional static eliminator, since the discharge needle for generating ions is structurally arranged near the product to be neutralized, there is a problem that the electric field created by the discharge needle adversely affects the product.

  On the other hand, for example, in Patent Document 1, it is proposed that an electric field generated by the discharge needle is not adversely affected on the static elimination target product by installing the discharge needle inside the jet outlet of the air duct. Yes. However, in this static eliminator, as shown in FIG. 2, a positive discharge needle 4A and a negative discharge needle 4B connected to a DC high-voltage power supply 3 are installed in one air duct 2 that blows out air containing ions. ing. For this reason, there is a problem in that the generated positive ions and negative ions come into contact with each other and are recombined until they are transported through the air duct 2 and reach the charge removal target area 5, thereby reducing the number of ions.

On the other hand, Patent Document 2 discloses a configuration in which positive and negative ions are mixed and supplied immediately before being supplied to a static elimination object after positive ions and negative ions are transferred by separate transfer paths. Furthermore, in order to adjust the balance of positive and negative ions at the supply end, it is disclosed that the number of supplied ions is adjusted by passing through a transport path charged to a charge opposite to that of the supplied ions.
JP 2003-36994 A JP 2007-258108 A

  However, in Patent Document 2, since the ion generating device and the ion transport path are provided separately, there is a problem that ions are likely to decrease due to friction with the inner wall surface of the transport path depending on the length of the ion transport path. Further, since the positive / negative ion balance at the air supply end is controlled mainly by passing through the transport path charged to a charge opposite to that of the supplied ions, the number of supplied ions tended to decrease slightly. For this reason, the static elimination time cannot be shortened sufficiently. Further, the product to be neutralized is not charged with positive ions and negative ions in a well-balanced manner, and usually there are many either, and the balance also changes with time.

  This invention is made | formed in view of such a situation, and it aims at providing the static elimination apparatus and method which can supply air with favorable ion balance, without reducing the number of ions extremely.

  According to a first aspect of the present invention, there is provided a static eliminator for supplying air containing ions from a jet outlet to a static eliminator in order to achieve the above object, and positive ion generating means for generating positive ions and negative ions are generated. Negative ion generating means, a positive ion transport path for transporting positive ions generated by the positive ion generating means, and a negative ion generated by the negative ion generating means are formed separately from the positive ion transport path A surface for measuring the surface potential of the object to be neutralized, comprising: a negative ion transport path that is formed; and a merge portion that is formed immediately before the ejection port and where the positive ion transport path and the negative ion transport path merge. And a control means for controlling the number of positive ions generated by the positive ion generation means and the number of negative ions generated by the negative ion generation means based on the measurement result. Providing a static eliminator for.

  According to the first aspect, the ion transport path is divided into the positive ion transport path and the negative ion transport path, and the positive ion transport path and the negative ion transport path are merged immediately before the ejection port. Thereby, it is possible to suppress recombination of positive ions and negative ions due to contact with each other immediately before the ejection port, and to prevent a decrease in the number of ions.

  Further, the surface potential of the static elimination object is measured by the surface potential measuring means, and the number of positive ions generated by the positive ion generating means and the number of negative ions generated by the negative ion generating means are controlled based on the measurement result. Means are provided. Thereby, according to the surface potential of the static elimination object, the number of positive ions and the number of negative ions to be generated can be controlled, and air with an appropriate ion balance can be supplied. In addition, as described above, positive ions and negative ions can be supplied in a well-balanced manner according to the surface potential of the charge removal object without drastically reducing the number of ions, so that the charge removal time can be shortened.

  A second aspect of the present invention is the method according to the first aspect, wherein the positive ion generating means is installed at a downstream position in the first direct current high voltage power source and the positive ion transport path, and a positive voltage is applied by the first direct current high voltage power source. And the negative ion generating means is installed at a downstream position in the negative ion transport path, and a negative voltage is applied by the second DC high voltage power source. And the control means controls the voltage applied to the positive electrode and / or the negative electrode by controlling the first DC high-voltage power supply and / or the second DC high-voltage power supply. It is characterized by adjusting.

  According to the second aspect, the positive electrode applied to the positive voltage by the first DC high-voltage power supply and the negative electrode applied to the negative voltage by the second DC high-voltage power supply are different from each other in the ion transport path (positive ion). Installed downstream of the transport path and negative ion transport path). Thereby, it is possible to prevent positive ions and negative ions from coming into contact with each other immediately after generation, and it is possible to suppress a decrease in the number of ions due to friction with the tube wall or the like by shortening the transport path length to the ejection port.

  In addition, the number of positive and negative ions generated is adjusted by controlling the voltage applied to the positive electrode and / or the negative electrode with the first DC high-voltage power supply and / or the second DC high-voltage power supply. The number of ions can be increased without changing.

  A third aspect of the present invention is characterized in that, in the first or second aspect, the positive ion transport path and the negative ion transport path are formed by partitioning the inside of one transport path by a partition plate.

  According to the third aspect, since the positive ion transport path and the negative ion transport path are formed by dividing the inside of one transport path by the partition plate, space can be saved. In this case, a partition plate is not installed at the junction.

  According to a fourth aspect of the present invention, there is provided a static elimination method characterized in that, in order to achieve the object, static elimination is performed using the static elimination apparatus according to any one of the first to third aspects.

  According to the present invention, air with good ion balance can be supplied without extremely reducing the number of ions.

  Hereinafter, preferred embodiments of a static eliminator and method according to the present invention will be described with reference to the accompanying drawings.

  First, an example of the configuration of the static eliminator according to the present invention will be described.

  FIG. 1 is a schematic side view showing an example of a schematic configuration of a static eliminator 10 used in the present invention.

  In the same figure, the static elimination apparatus 10 is mainly provided in the ventilation duct 14 which blows out the air containing ion (positive ion, negative ion) toward the static elimination object 12, and is provided in the inside of this ventilation duct 14, and is positive ion and negative. Discharge needles 16A (positive electrodes) and 16B (negative electrodes) that generate ions respectively, and DC high-voltage power supplies 18A and 18B that are connected to the discharge needles 16A and 16B and apply a high potential, respectively. Further, the static eliminator 10 includes a surface measurement meter 20 that measures the surface potential of the static elimination object 12, and a control unit 22 that controls the voltage applied to the discharge needles 16A and 16B in the DC high-voltage power supplies 18A and 18B based on the measurement results. And are provided.

  The blower duct 14 is connected to a blower fan 24, and is configured so that air flows therein. As shown in FIG. 1, a partition plate 28 is provided inside the blower duct 14 except just before the jet outlet 26, thereby forming two ion transport paths.

  A discharge needle 16A to which a positive voltage is applied is provided on the downstream side in one ion transport path, and a discharge needle 16B to which a negative voltage is applied is provided on the downstream side in the other ion transport path. As a result, the ion transport path in which the discharge needle 16A is installed becomes a positive ion transport path 14A in which only positive ions are generated and transported, and the ion transport path in which the discharge needle 16B is installed generates and transports only negative ions. Negative ion transport path 14B. As the installation positions of the discharge needles 16A and 16B, for example, in order to suppress the reduction due to the friction of ions without affecting the static elimination object and about 300 mm inside (air flow) It is preferable that the flow direction be upstream).

As a material of the partition plate 28, for example, an insulator such as acrylic or vinyl chloride is preferable, and an insulator having a resistance of 10 ¹² Ω or more is particularly preferable. In addition, the installation aspect of the partition plate 28 is not limited to FIG. 1, You may provide only in the downstream part containing discharge needle 16A, 16B.

  A junction 30 where the positive ion transport path 14A and the negative ion transport path 14B merge is formed immediately before the outlet 26 of the air duct 14. This junction 30 has a function of mixing positive ions and negative ions.

  The length of the merging portion 30 is set to a length suitable for mixing positive ions and negative ions in a balanced manner. Specifically, the length of the merging portion 30 depends on conditions such as the air flow rate, but is preferably about 100 mm, for example. If the confluence 30 is too long, positive ions and negative ions come into contact with each other and recombine, which is not preferable because the number of ions becomes extremely small. Here, the length of the merging portion refers to the length in the ion transport direction.

  The discharge needles 16A and 16B are connected to DC high-voltage power supplies 18A and 18B via high-voltage wires 32A and 32B, respectively. As a result, a positive voltage is applied to the discharge needle 16A by the DC high-voltage power supply 18A through the high-voltage wire 32A, and a negative voltage is applied to the discharge needle 16B by the DC high-voltage power supply 18B through the high-voltage wire 32B. Thus, the voltage is independently applied to the discharge needles 16A and 16B. And by making corona discharge in each of the discharge needles 16A and 16B, positive ions are generated in the vicinity of the discharge needle 16A, and negative ions are generated in the vicinity of the discharge needle 16B. In this case, the inner wall of the air duct 14 and the partition plate 28 are grounded as the counter electrode.

  The surface potential meter 20 outputs the surface potential of the charge removal object 12 based on a signal from the probe 21 that measures the surface potential of the charge removal object 12. For example, a known surface potential sensor can be used as the probe 21.

  The control unit 22 calculates a balance of positive ions and negative ions suitable for the surface potential of the static elimination object measured by the surface potential meter 20. The control unit 22 controls the DC high-voltage power supplies 18A and 18B so as to adjust the voltage applied to the discharge needles 16A and 16B based on the calculation result.

  Next, the operation of the static eliminator 10 according to the present invention will be described.

  First, a positive voltage is applied to the discharge needle 16A by a DC high-voltage power supply 18A, and a negative voltage is applied to the discharge needle 16B by a DC high-voltage power supply 18B. Thereby, corona discharge is caused in each of the discharge needles 16A and 16B, and positive ions or negative ions are generated. On the other hand, when air flows into the blower duct 14 from the blower fan 24, the positive ions generated by the discharge needle 16A are transported together with the air in the positive ion transport path 14A. Similarly, in the negative ion transport path 14B, negative ions generated by the discharge needle 16B are transported together with air. During this time, since positive ions and negative ions pass through separate transport paths, they do not contact each other, and the number of ions does not decrease.

  The air containing positive ions flowing in the positive ion transport path 14 </ b> A and the air containing negative ions flowing in the negative ion transport path 14 </ b> B merge at the junction 30 immediately before the jet nozzle 26. Then, air containing positive ions and negative ions in a well-balanced manner is blown out from the outlet 26.

  As described above, in the present embodiment, positive ions and negative ions are generated and transported in separate transport paths, and the positive ions and negative ions are mixed immediately before the ejection port 26. Thereby, it can suppress that a positive ion and a negative ion contact and recombine in the middle of ion conveyance to the jet nozzle 26 after ion production | generation. Further, since the discharge needles 16A and 16B are installed on the downstream side in the positive ion transport path 14A and the negative ion transport path 14B, the transport path length from the generation of ions to the jet outlet 26 can be shortened. . Thereby, it is possible to suppress the number of ions from decreasing due to friction between positive and negative ions and the inner wall surfaces of the air duct 14 and the partition plate 28.

  Furthermore, in this embodiment, the surface potential of the static elimination object 12 is measured by the surface potential meter 20, and based on the measurement result, the control unit 22 performs direct current so that the ion balance is appropriate for the surface potential of the static elimination object 12. The high voltage power supplies 18A and 18B are controlled. Thereby, since the number of positive and negative ions generated in the discharge needles 16 </ b> A and 16 </ b> B can be adjusted, it is possible to supply ion balance air suitable for the surface potential of the static elimination object 12.

  As mentioned above, although preferable embodiment of the static elimination apparatus which concerns on this invention was described, this invention is not limited to the said embodiment, Various aspects can be taken.

  For example, in the present embodiment, the example in which the positive ion transport path and the negative ion transport path are respectively formed by providing the partition plate 28 in one air duct 14 has been described, but the present invention is not limited thereto. For example, two air ducts may be provided, each of which serves as a positive ion transport duct and a negative ion transport duct, and the downstream ends of the two air ducts may be merged immediately before the outlet.

  In the present embodiment, the DC high-voltage power supply is used and the positive ion transport path 14A and the negative ion transport path 14B are fixed. However, the AC high-voltage power supply is used and two adjacent air ducts 14 are used. You may comprise so that the ion produced | generated within a conveyance path may be switched sequentially so that it may mutually become a pair. In short, the applied voltages of the discharge needles 16A and 16B can be controlled independently so that ions flowing in the two transport paths are always paired.

  Moreover, in this embodiment, although the example which controls an applied voltage about both discharge needle 16A, 16B was shown, it is not limited to this, For example, according to the surface potential of the static elimination target 12, any one discharge needle Only the applied voltage may be changed.

  The static eliminator of the present invention can be used in a wide range of technical fields, and can be preferably used, for example, in the manufacture and transportation processes of various electronic products.

It is a schematic side view which shows an example of schematic structure of the static elimination apparatus in this Embodiment. It is explanatory drawing which shows the structure of the conventional static elimination apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Static elimination apparatus, 12 ... Static elimination target object, 14 ... Air blow duct, 14A ... Positive ion conveyance path, 14B ... Negative ion conveyance path, 16A, 16B ... Discharge needle, 18A, 18B ... DC high voltage power supply, 20 ... Surface potential measurement Total: 21 ... Probe, 22 ... Control part, 26 ... Jet, 28 ... Partition plate, 30 ... Junction part

Claims (4)

A static eliminator that supplies air containing ions from a jet nozzle to a static eliminator,
Positive ion generating means for generating positive ions;
Negative ion generating means for generating negative ions;
A positive ion transport path through which positive ions generated by the positive ion generating means are transported;
A negative ion transport path that is formed separately from the positive ion transport path and that transports negative ions generated by the negative ion generating means;
A merging portion that is formed immediately before the spout, and where the positive ion transport path and the negative ion transport path merge,
Surface potential measuring means for measuring the surface potential of the static elimination object;
Control means for controlling the number of positive ions generated by the positive ion generating means and the number of negative ions generated by the negative ion generating means based on the measured result;
A static eliminator characterized by comprising: The positive ion generating means includes a first DC high-voltage power source and a positive electrode that is installed at a downstream position in the positive ion transport path and to which a positive voltage is applied by the first DC high-voltage power source,
The negative ion generation means includes a second DC high-voltage power supply, and a negative electrode that is installed at a downstream position in the negative ion transport path and to which a negative voltage is applied by the second DC high-voltage power supply,
The control means adjusts the voltage applied to the positive electrode and / or the negative electrode by controlling the first DC high-voltage power supply and / or the second DC high-voltage power supply. 1. The static eliminator according to 1.   The static eliminator according to claim 1 or 2, wherein the positive ion transport path and the negative ion transport path are formed by partitioning the interior of one transport path by a partition plate.   The static elimination method characterized by carrying out static elimination using the static elimination apparatus of any one of Claims 1-3.

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