JP2009202131A - Liquid coating apparatus and liquid coating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid coating apparatus and a liquid coating method which can disperse liquid widely with a lower applied voltage than ever. <P>SOLUTION: The liquid coating apparatus 1 coating a coating object 2 with a liquid 9 includes: a mounting platform 3 mounting the coating object 2; a nozzle 4 disposed facing the coating object 2 mounted on the mounting platform 3 and ejecting the liquid 9 to the coating object 2; a first electrode 6 electrostatically charging the liquid 9 in the nozzle 4; a second annular electrode 7 disposed around the nozzle 4 which is to be a center axis; and a third electrode 8 fixed on the mounting platform 3 so as to apply electric potential to the coating object 2 wherein the electric potential is set so that a potential V2 of the second electrode 7 is between a potential V1 of the first electrode 6 and a potential V3 of the third electrode 8. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid coating apparatus and a liquid coating method. More specifically, the present invention relates to a liquid application apparatus and a liquid application method for applying an electrostatic force to a nozzle to spray a liquid in a spray state and applying the liquid over a wide range of the surface of an object to be coated.

  Conventionally, when a liquid is ejected from a nozzle, an electrostatic force is applied to the nozzle to generate droplets, liquid yarn, and mist, and control the direction of the liquid flow. For example, a thin film manufacturing apparatus has been proposed in which an object to be coated is arranged in the axial direction of the nozzle, an electrostatic force is applied in the axial direction of the nozzle, and the liquid is ejected in a string shape. According to this, depending on the voltage applied to the nozzle and the object to be coated and the specific resistance of the liquid, the liquid state changes in three ways: (a) droplet-like, (b) string-like, (c) spray-like, A high voltage is required for spraying. (For example, see Patent Document 1)

JP-A-8-71489 (paragraphs 0023 to 0104, FIGS. 1 to 8)

  However, in the conventional apparatus such as the above-described thin film manufacturing apparatus, the distance between the nozzle and the object to be coated is increased in order to perform the coating over a wide range. Becomes difficult to disperse. Therefore, there has been a problem that a high voltage is required to compensate for the electrostatic force reduced by increasing the distance. On the other hand, when a high voltage is applied, discharge occurs between the nozzle tip and the coating object, and there is a problem that the nozzle tip and the coating object are destroyed. In addition, when applying a conductive liquid, it may be necessary to ensure a large insulation distance because a discharge may occur between the nozzle tip and the object to be coated via the liquid. Similarly, there has been a problem that the electrostatic force between the nozzle and the object to be coated is reduced and a high voltage is required. As described above, it is difficult to set the distance between the nozzle tip and the coating object suitable for coating in the trade-off relationship between the distance between the nozzle tip and the coating object and the applied voltage.

  An object of the present invention is to provide a liquid coating apparatus and a liquid coating method capable of coating a liquid dispersedly over a wide range with a lower applied voltage than conventional ones.

  In order to solve the above problems, a liquid application apparatus 1 according to a first aspect of the present invention is a liquid application apparatus that applies a liquid 9 to an object 2 as shown in FIG. A mounting table 3 on which the object 2 is mounted; a nozzle 4 which is disposed opposite to the object 2 to be applied placed on the mounting table 3 and which discharges the liquid 9 toward the object 2; A first electrode 6 that charges the liquid 9, an annular second electrode 7 that is disposed around the nozzle 4 with the nozzle 4 as a central axis, and a mounting table 3 that applies a potential to the workpiece 2. And the potential of the second electrode 7 is set so that the potential of the second electrode 7 is between the potential of the first electrode 6 and the potential of the third electrode 8.

  Here, as a combination of the object to be coated 2 and a liquid, a combination of a semiconductor wafer and a resist, an insulating film solution, a diffusing agent and a protective film solution, a combination of glass, a lens and a coating solution, a combination of sheet metal, a plating solution and paint. Etc. Alternatively, molten polymer can be sprayed onto trays or molds to obtain nano-sized polymer particles, fibers, and the like. Further, the phrase “the nozzle 4 is disposed so as to face the object 2” means that the object 2 is disposed in the liquid discharge direction from the nozzle 4. Typically, it is preferable that the object to be coated 2 is placed horizontally, the nozzle 4 is arranged vertically above the surface of the object to be coated 2, and the center of the object to be coated 2 coincides with the axis of the nozzle 4. However, the present invention is not necessarily limited to this, and the liquid may be disposed so as to be spread over a wide range on the surface of the workpiece 2. In addition, the first electrode 6 makes the liquid 9 in the nozzle 4 charged. When the nozzle 4 is made of a conductor, the nozzle 4 itself is used as the first electrode 6 and contacts the liquid 9 inside. The internal liquid 9 may be charged, and is electrically connected to the nozzle 4 from a separately provided electrode connecting portion 6A. The first electrode 6 including the electrode connecting portion 6A and the nozzle 4 is used as the first electrode 6 in the nozzle 4. The liquid 9 may be charged. Further, in these cases, the nozzle 4 may be covered with a conductor on the inside contacting the liquid 9 and covered with an insulator on the outside. In this case, the inside of the nozzle 4 is connected to the power source through the electrode connecting portion 6A. Electrically connected. When the nozzle 4 is made of an insulator, the first electrode 6 disposed in the vicinity of the inlet of the nozzle 4 comes into contact with the liquid 9 penetrating therethrough and the liquid 9 is charged and sent into the nozzle 4. But it ’s okay. The term “annular” typically means an annular shape, but may be an elliptical shape, a rectangular shape, or a polygonal shape. Moreover, even if a part of the ring is interrupted, it is sufficient that the majority of the ring is configured as an electrode. The third electrode 8 is attached to the mounting table 3 so as to apply a potential to the object 2. For example, if the object 2 is a conductor, the electrode is placed in contact with the object 2. If the mounting table 3 is a conductor, an electrode may be connected to a part of the mounting table 3, and if the mounting table 3 is an insulator, a disk-shaped or donut-shaped electrode is formed on the upper and lower portions thereof. Or a disk-shaped or donut-shaped electrode may be embedded in the mounting table 3. In this way, the electric lines of force pass through the object to be applied 2 placed on the mounting table 3 and reach the electrode, so that a potential can be applied to the object to be coated 2.

  With this configuration, by providing the second electrode 7, the liquid is dispersed even if the voltage V 1 -V 3 between the nozzle 4 and the mounting table 3 is reduced as compared to the case where the second electrode 7 is not provided. Can be applied. Further, assuming that the distance between the first electrode 6 and the second electrode 7 is constant, the spray from the first electrode 6 toward the third electrode 8 is substantially conical, so that the article 2 is placed. When the third electrode 8 is moved away from the nozzle 4, the spraying range can be expanded, and conversely, when the third electrode 8 is brought closer, the spraying range can be narrowed. Therefore, it is possible to provide a liquid coating apparatus capable of coating a liquid dispersed in a wide range with a lower applied voltage than in the past.

  Further, in the liquid coating apparatus 1 according to the second aspect of the present invention, in the first aspect, as shown in FIG. 2B, for example, the electric force from the first electrode 6 to the third electrode 8 is obtained. The line extends radially outward from the nozzle 4 and is formed to reach the third electrode 8 after approaching the second electrode 7. If comprised in this way, since the force which moves the charged liquid microparticles | fine-particles along an electric-force line will act, it can apply | coat the wide range of the to-be-coated object 2 surface.

  In addition, the liquid application apparatus 1A according to the third aspect of the present invention is the first or second aspect in which, as shown in FIG. 4, for example, the first between the first electrode 6 and the second electrode 7 is the first. The second resistor R2 is provided between the second electrode 6 and the third electrode 7, and the potential difference V1-V2 between the first electrode 6 and the second electrode 7 is The ratio of the potential difference V2-V3 between the electrode 7 and the third electrode 8 is set by the ratio of the resistance values of the first resistor R1 and the second resistor R2. If comprised in this way, since resistance R1, R2 can be used, the structure of an electric potential provision means can be simplified and reduced in size.

  In addition, the liquid application apparatus 1 according to the fourth aspect of the present invention is the first or second aspect in which the first electrode 6 and the third electrode 8 are arranged between the first electrode 6 and the third electrode 8 as shown in FIG. The second power source E2 is provided between the second electrode 7 and the third electrode 8, and the potential difference V1-V2 between the first electrode 6 and the second electrode 7 is The ratio of the potential difference V2-V3 between the electrode 7 and the third electrode 8 is set by the ratio of the electromotive forces of the first power supply E1 and the second power supply E2. With this configuration, the potential can be easily adjusted by the power supplies E1 and E2.

Further, in any one of the first to fourth aspects, the liquid coating apparatus 1B according to the fifth aspect of the present invention is such that the second electrode 7 is insulated at least at the outer peripheral side and the end of the nozzle in the liquid ejection direction Covered with body. If comprised in this way, the electric field concentration to the edge part of the liquid discharge direction side of a nozzle will be relieve | moderated on the outer peripheral side. Further, for example, as shown in FIGS. 5 and 6, when not only the end portion but also the entire outer peripheral side and the entire mounting table side are covered with an insulator, the sprayed liquid is applied to the main body portion 7B and the electrode of the second electrode 7A. Since it can be prevented from adhering to the cover 10, the main body portion 7B is corroded by the adhering droplets, and extra liquid adheres to the work or stage disposed below the second electrode 7A due to the dropping of the droplets. Can be prevented. In order to maintain insulation, the relative dielectric constant ε _S is preferably 2 or more, and more preferably higher.

  Further, in the liquid coating apparatus 1 according to the sixth aspect of the present invention, in the first aspect, for example, as shown in FIG. 1, the second electrode 7 is disposed on the side opposite to the liquid discharge direction from the tip of the discharge port 4. Installed at a predetermined length. Here, the predetermined length means that the sprayed liquid (mist) is prevented from adhering to the second electrode 7 and the electric lines of force extending from the first electrode 6 to the third electrode 8 are widened. Although it depends on the radius of the second electrode 7, for example, 1 to 10 mm is preferable, and 5 to 10 mm is more preferable. If comprised in this way, it will become difficult for a spray-like liquid to adhere to the 2nd electrode 7, and when the electric wire in any one of the 1st electrode 6 and the 2nd electrode 7 is disconnected, the 1st Even if a discharge occurs between the electrode 6 and the second electrode 7, since the distance is a predetermined length, the possibility of a discharge occurring at the tip of the nozzle 4 is reduced, and the tip is protected.

  In order to solve the above problem, a liquid application method according to a seventh aspect of the present invention is a liquid application method for applying a liquid to an object to be applied 2 as shown in FIG. Is placed on the mounting table 3, and the coating object placement step (S 1) is arranged so as to face the nozzle 4 that discharges the liquid 9 toward the coating object 2, and the liquid 9 in the nozzle 4 is charged. A first electrode 6, an annular second electrode 7 disposed around the nozzle 4 with the nozzle 4 as a central axis, and a third electrode attached to the mounting table 3 so as to apply a potential to the workpiece 2. From the nozzle 4, a potential setting step (S 2) for setting the potential so that the potential of the second electrode 7 is between the potential of the first electrode 6 and the potential of the third electrode 8 with respect to the electrode 8. A liquid spraying process in which liquid is discharged toward the object to be coated 2 and the liquid is sprayed on the entire surface of the object to be coated 2 ( 3) and a.

  With this configuration, by using the second electrode 7, even if the voltage V1-V3 between the nozzle 4 and the mounting table 3 is reduced as compared with the case where the second electrode 7 is not provided, the liquid is dispersed. Can be applied. Therefore, it is possible to provide a liquid application method capable of applying a liquid dispersed in a wide range with an applied voltage lower than that in the prior art.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid application apparatus and liquid application method which can apply | coat by disperse | distributing a liquid to a wide range with the applied voltage lower than before can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
FIG. 1 shows an example of the configuration of the liquid coating apparatus in the first embodiment. In FIG. 1, 1 is a liquid coating device. Reference numeral 2 denotes an object to be coated, which is placed on the placing table 3. In the present embodiment, the mounting table 3 is installed horizontally, and the nozzle 4 is installed facing the mounting table 3 vertically downward. The nozzle 4 is connected to a liquid tank (not shown) via an operating valve 5, and when the operating valve 5 is opened, liquid is supplied from the liquid tank to the nozzle 4. Initially, the operating valve 5 is closed.

  The nozzle 4 is formed of a conductor such as a metal or an alloy, the electrode connecting portion 6A is electrically connected to the nozzle 4, and the electrode connecting portion 6A and the nozzle 4 constitute the first electrode 6. The nozzle 4 only needs to be electrically conductive at the portion in contact with the inner liquid 9, and the periphery may be covered with an insulator. As a result, the liquid in the nozzle is charged and dispersed in a spray form from the discharge port. The nozzle 4 has a tapered annular shape in the vicinity of the discharge port to narrow down the discharge port so that many of the discharged liquid particles (spray, that is, individual liquid particles constituting the mist) are charged. The second electrode 7 is arranged around the nozzle 4 with the nozzle 4 as a central axis. The reason why the position of the second electrode is made higher than the discharge port of the nozzle 4 is to prevent mist from adhering to the second electrode and to prevent discharge between the nozzle 4 and the second electrode. For example, the distance from the tip of the discharge port of the nozzle 4 to the second electrode 6 is preferably 1 to 10 mm, and more preferably 5 to 10 mm. Further, if the gap between the nozzle 4 and the second electrode 7 is narrow, discharge occurs, and if it is large, the electric field does not act effectively, so it is necessary to set it within an appropriate range. For example, when the outer diameter of the nozzle 4 is 6 mm at the maximum, the inner diameter of the second electrode 7 is preferably 10 to 20 mm. Further, the third electrode 8 is attached to the mounting table 3 so as to apply a potential to the workpiece 2 mounted on the mounting table 3. The third electrode 8 is grounded, and the potential V3 of the third electrode 8 is 0V. For example, the third electrode 8 is integrally attached to the upper part of the mounting table 3. Although not shown, a work that supports and moves the nozzle 4 and the second electrode 7, a work that places and removes the workpiece 2 on the placement table 3, a work that moves the placement table 3 up and down, the placement table 3, and these There is a stage equipped with this work.

  In the present embodiment, the ratio of the potential difference V1-V2 between the first electrode 6 and the second electrode 7 and the potential difference V2-V3 between the second electrode 7 and the third electrode 8 is the power supply The example set by the ratio of electromotive force is shown. E1 and E2 are first and second power supplies, and SW1 and SW2 are first and second switches for turning on and off the connection between the first and second power supplies E1 and E2 and the first and second electrodes 6 and 7, respectively. Switch. When the first switch SW1 is turned on, the voltage V1-V3 is applied between the first electrode 6 and the third electrode 8 by the electromotive force of the first power supply E1, and the potential V1 is applied to the nozzle 4. When the second switch SW2 is turned on, the voltage V2-V3 is applied between the second electrode 7 and the third electrode 8 by the electromotive force of the second power source E2, and the potential V2 is applied to the second electrode 7. Is done. As a result, a potential difference V1-V2 is given between the nozzle 4 and the second electrode 7. Here, the potential V2 of the second electrode 7 is set to be between the potential V1 of the first electrode 6 and the potential V3 of the third electrode 8, that is, V1> V2> V3 (= 0V). The In the drawing, potentials V1 to V3 applied to the first to third electrodes 6 to 8 are shown in parentheses. For example, if the voltage V1-V3 applied between the first electrode 6 and the third electrode 8 is 10 kV, and the voltage V2-V3 applied between the second electrode 7 and the third electrode 8 is 6 kV, The voltage V1−V2 applied between the nozzle 4 and the second electrode 7 becomes 4 kV, and the potential difference (V1−V2) between the potential V1 of the first electrode 6 and the potential V2 of the second electrode 7 and the second The ratio of the potential V2 of the electrode 6 and the potential difference (V2-V3) between the third electrode 8 is 3: 2. In the present embodiment, there is an advantage that the potential can be easily adjusted by making the electromotive forces of the first and second power sources E1 and E2 variable. Further, by configuring the first and second switches SW1 and SW2 to open and close in conjunction with each other, only one of the first and second switches SW1 and SW2 is opened. An increase in the potential difference between the second electrodes 7 can be prevented. In addition, it is possible to prevent the occurrence of a shift in the timing of voltage application to each electrode due to the time difference between on and off of the switch, and it is possible to instantly form and eliminate appropriate lines of electric force.

  When the operating valve 5 is opened with the potential set in this manner and the liquid is supplied to the nozzle 4, the liquid is sprayed and dispersed by the action of the electrostatic force. When no voltage is applied between the nozzle 4 and the third electrode 8, the liquid is dropped vertically downward by the initial velocity and gravity discharged from the nozzle, but when the voltage is applied, the liquid 9 The electric charge is obtained from 4 and is misted, and is applied to the surface of the object to be coated 2 on the mounting table 3 by receiving a force that moves along the electric lines of force formed between the electrodes. As a result, the liquid is applied to the workpiece 2.

  FIG. 2 shows the difference in the lines of electric force depending on the presence / absence of the second electrode 7. FIG. 2A schematically shows the lines of electric force when the second electrode 7 is not present and FIG. 2B when the second electrode 7 is present. The liquid coating apparatus of FIG. That is, when there is no second electrode 7, as shown in FIG. 2A, the lines of electric force are formed in a substantially conical shape from the nozzle 4 toward the mounting table 3 and discharged from the nozzle 4. The liquid fine particles are dispersed on the object to be coated 2 along the electric lines of force formed between the first electrode 6 and the third electrode 8. On the other hand, when there is the second electrode 7, as shown in FIG. 2B, the electric lines of force are formed so as to spread radially from the nozzle 4, and the liquid fine particles are formed on the surface of the article 2 to be coated. It will be spread over a wide area. In this case, the electric lines of force φ2 between the first electrode 6 and the third electrode 8 radiate outward from the nozzle 4, are guided in the direction of the second electrode 7, and are almost directly below the second electrode 7. Then, it approaches the second electrode 7 most and then is guided in the direction of the third electrode 8, that is, downward. At least the electric lines of force φ2 extend beyond the radius of the second electrode 7 in the outer peripheral direction and are formed so as to reach the third electrode 8. Thereby, compared with the case where there is no 2nd electrode 7, a liquid fine particle is spread | diffused in the wide range. Moreover, since the diffusion direction of the liquid fine particles is mainly determined by the first electrode 6 and the second electrode 7, the interval between the first electrode 6 and the third electrode 8 can be freely set according to the application range. Can do. That is, when it is desired to increase the application range, the position of the mounting table 3 on which the object 2 is placed is lowered, and when the application range is desired to be reduced, the position of the mounting table 3 on which the object 2 is placed is set. Just raise it.

  FIG. 3 shows an example of a processing flow of the liquid application method according to the present embodiment. First, the object to be coated 2 is placed on the mounting table 3 and disposed to face the nozzle 4 made of a conductor (coating object placement step: step S1). At this time, the mounting table 3 on which the coating object 2 is placed may be moved below the nozzle 4, or the nozzle 4 may be moved on the mounting table 3 on which the coating object 2 is placed, The nozzle 4 may be arranged on the mounting table 3, and the workpiece 2 may be transferred onto the mounting table 3 by a belt conveyor or the like. Next, the first switch SW1 is turned on, the voltage V1-V3 is applied between the first electrode 6 and the third electrode 8 by the electromotive force of the first power supply E1, and the potential V1 is applied to the nozzle 4. To do. Further, the second switch SW2 is turned on, and the voltage V2-V3 is applied between the second electrode 7 and the third electrode 8 by the electromotive force of the second power supply E2, and is arranged around the nozzle 4. A potential V2 is applied to the annular second electrode 7 (potential setting step: S2). As a result, a potential difference V1-V2 is applied between the nozzle 4 and the second electrode 7. Since the first switch SW1 and the second switch SW2 are opened and closed in conjunction with each other, the potentials V1 and V2 are simultaneously applied to the first electrode 6 and the second electrode 7 by turning on the first switch SW1 and the second switch SW2. At this time, the potential V2 of the second electrode is set to be between the potential V1 of the first electrode and the potential of the third electrode, that is, V1> V2> V3 (= 0 V). Set.

  Next, the operation valve 5 is opened to introduce a liquid into the nozzle 4, and the liquid 9 is ejected from the nozzle 4 toward the application object 2. Thereby, a liquid fine particle is sprayed on the whole surface of the to-be-coated object 2 (liquid spraying process: S3). The liquid 9 ejected from the nozzle 4 is misted (sprayed) because the voltage V1-V2 is applied between the nozzle 4 and the second electrode 7, and the spraying range is expanded. More specifically, basically, the misted liquid 9 is scattered in the direction of the coating object 2 by the action of the electric field formed between the nozzle 4 and the coating object 2. However, due to the action of the electric field formed between the nozzle 4 and the second electrode 7, the liquid 9 that has been mist is emitted radially from the nozzle 4 as the central axis (from the inner periphery to the outer periphery of the coating object 2). The power to spread is working. For this reason, the liquid 9 ejected from the nozzle 4 is attracted and scattered from the nozzle 4 in the direction of the second electrode 7 and spreads outward in the radial direction around the nozzle 4. The electric field formed between the two is dispersed toward the object to be coated 2. For example, if the voltage V1-V3 applied between the first electrode 6 and the third electrode 8 is 10 kV, and the voltage V2-V3 applied between the second electrode 7 and the third electrode 8 is 6 kV, The ratio of the potential difference V1-V2 between the first electrode 6 and the second electrode 7 and the potential difference V2-V3 between the second electrode 7 and the third electrode 8 is 2: 3. In this way, the liquid 9 is dispersed and applied to the object 2 by the action of the electric field formed between the nozzle 4 and the object 2 and the action of the electric field formed between the nozzle 4 and the second electrode 7. Therefore, compared to the case where the second electrode 7 is not provided, it is possible to sufficiently expand the coating area even when the voltage V1-V3 between the nozzle 4 and the workpiece 2 is reduced. Become.

  Next, the operation valve 5 is closed to stop introducing the liquid into the nozzle 4 (step S4), and the first and second switches SW1 and SW2 of the first and second power sources E1 and E2 are turned off. (Step S5). The first switch SW1 and the second switch SW2 are opened and closed in conjunction with each other. Next, the workpiece 2 is taken out from the mounting table 3 (step S6).

  According to the present embodiment, by providing the second electrode 7, even when the voltage V <b> 1-V <b> 3 between the nozzle 4 and the mounting table 3 is reduced as compared with the case where the second electrode 7 is not provided, The liquid 9 can be dispersed and applied. By providing the second electrode 7, for example, when the distance between the first electrode 6 and the third electrode 8 is 100 mm, a coating area of about 1.5 times can be obtained. Therefore, by providing the second electrode 7, it is possible to provide a liquid coating apparatus and a liquid coating method that can be applied by dispersing the liquid over a wide range by reducing the applied voltage as compared with the case where the second electrode 7 is not provided.

[Second Embodiment]
In the first embodiment, the ratio of the potential difference between the first electrode and the second electrode and the ratio of the potential difference between the second electrode and the third electrode are set by the ratio of the electromotive force of the power source. Although the example has been described, in the second embodiment, the ratio of the potential difference between the first electrode and the second electrode and the potential difference between the second electrode and the third electrode is the resistance value of the resistor. An example in which the ratio is set will be described.

  FIG. 4 shows a configuration example of the liquid coating apparatus according to the second embodiment. In FIG. 2, the same parts as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted (the same applies to the following embodiments). Differences from the first embodiment will be mainly described. Voltages V1-V3 are applied between the first electrode 6 and the third electrode 8 by the electromotive force of the first power supply E1 (this is the same as in the first embodiment). A third switch SW3 is provided between the first power supply E1 and the first electrode 6. A first resistor R1 is installed between the first electrode 6 and the second electrode 7, and a second resistor R2 is installed between the second electrode 7 and the third electrode 8, whereby the first resistor R1 is installed. The ratio of the potential difference (V1−V2) between the first electrode 6 and the second electrode 7 and the potential difference (V2−V3 = V2) between the second electrode 7 and the third electrode 8 is It is determined by the ratio of the resistance values of the resistor R1 and the second resistor R2. This ratio is, for example, 3: 2. By turning on the third switch SW3, the potentials V1 and V2 are simultaneously applied to the first electrode 6 and the second electrode 7. Since the potential applying circuit is configured by a resistor, there is an advantage that it can be configured simply and compactly. If the resistance is increased, the capacity of the power source can be reduced. In particular, the supply of voltage to each electrode is performed by only one set of the first power supply E1 and the third switch SW3. Therefore, the timing difference in voltage application to each electrode due to the delay time when the switch is turned on / off. Can be prevented, and appropriate lines of electric force can be formed and eliminated instantly. Other configurations and processing flow are the same as those of the first embodiment, and the same effects as those of the first embodiment are obtained.

[Third Embodiment]
In the first embodiment, the example in which the second electrode is an annular electrode has been described. In the third embodiment, the lower end of the outer periphery of the second electrode is covered with an insulator. explain. Differences from the first embodiment will be mainly described.

FIG. 5 shows a configuration example of the liquid coating apparatus 1B in the third embodiment, and FIG. 6 shows a configuration example of the second electrode 7A in the third embodiment. At least the end portion (edge portion) on the liquid discharge direction side of the nozzle on the outer peripheral side of the main body portion 7B of the second electrode 7A is covered with an insulating electrode cover 10. FIG. 6A is a perspective view of the second electrode 7A having the insulating electrode cover 10, and FIG. 6B is a cross-sectional view taken along the line AA in FIG. Show. 5 and 6, the second electrode having the cover 10 is indicated by 7A, and the annular electrode main body is indicated by 7B. Most of the outer side of the annular electrode body 7B and the liquid discharge direction side (lower side in the present embodiment) are covered with an electrode cover 10 of an insulator having a high dielectric constant. As the insulator, for example, Teflon (registered trademark) (relative permittivity ε _S = about 2) can be used. By covering at least the end portion of the nozzle on the liquid discharge direction side with the insulator on the outer peripheral side of the annular electrode main body portion 7B, it is possible to provide an electrode configuration in which the concentration of the electric field at the end portion is relaxed and discharge can be prevented. Furthermore, as shown in FIGS. 5 and 6, when the entire outer peripheral side and the entire mounting table side are covered with an insulator, the electric field around the second electrode 7A is weakened, and the charged and mist-like liquid fine particles are formed in the second annular shape. Can be prevented from adhering to the electrode main body portion 7B and the electrode cover 10, so that the main body portion 7B is corroded by the adhering liquid droplets, and the workpiece disposed below the second electrode 7A due to the drop of the liquid droplets It is possible to prevent extra liquid from adhering to the stage. Other configurations and processing flow are the same as those in the first embodiment.

[Fourth Embodiment]
In the first embodiment, the second electrode is an annular electrode and the object to be coated and the mounting table are circular. However, in the fourth embodiment, the second electrode is rectangular. An example in which the object to be coated and the mounting table are rectangular will be described. Even if the shape of the second electrode is rectangular, the liquid fine particles discharged from the nozzle are formed between the first electrode and the third electrode when the potential V2 is applied to the second electrode. The electric field lines are formed so as to spread, and the liquid fine particles are spread over a wide range. Since the spread of the lines of electric force and the spread of the liquid fine particles depend on the shape of the second electrode, it is desirable that the shape of the second electrode is also rectangular when the object to be coated is rectangular. Other configurations and processing flow are the same as those in the first embodiment.

[Fifth Embodiment]
In the first embodiment, an example in which the third electrode is circular and attached to the upper portion of the mounting table has been described. However, in the fifth embodiment, an example in which the third electrode has a donut shape and is attached to the lower portion of the mounting table. explain.

  FIG. 7 shows an example of the third electrode 8A in the fifth embodiment. FIG. 7A is a perspective view as seen from the front bottom side, and FIG. 7B is a cross-sectional view through the central axis. An example in which the outer periphery of the donut shape coincides with the outer periphery of the mounting table 3 is shown. On the surface of the object 2 near the center axis of the nozzle 4, the liquid fine particles are affected by the initial velocity and gravity, and the amount of application tends to be larger than the outer periphery of the object 2. In order to suppress this, the doughnut-shaped third electrode 8A is attached to the lower part of the non-conductive mounting table 3. In the present embodiment, although it depends on the thickness of the workpiece 2 and the mounting table 3, electric lines of force similar to those in the first embodiment are formed except for the donut-shaped hole portion. Accordingly, it is possible to prevent the liquid from being applied excessively in the vicinity of the object 2 just below the nozzle 4 and to apply the liquid uniformly. Other configurations and processing flow are the same as those in the first embodiment.

[Sixth Embodiment]
In the first embodiment, an example in which a single annular second electrode 7 is arranged with the nozzle as the central axis has been described, but in the sixth embodiment, a plurality of annular electrodes are arranged with the nozzle as the central axis. A description will be given of the case.

  FIG. 8 shows a configuration example of a liquid coating apparatus 1C according to the sixth embodiment. Differences from the first embodiment will be mainly described. An annular fourth electrode 74 around the nozzle 4 with the nozzle 4 as the central axis is located above the workpiece 2 placed on the mounting table 3 and slightly below the nozzle 4 with the nozzle 4 as the central axis. An annular fifth electrode 75 is disposed. The fourth electrode 74 is close to the nozzle 4 and is disposed at a relatively high position. The potential V4 of the fourth electrode 74 and the potential V5 of the fifth electrode 75 are set such that V1> V4> V5> V3 by the electromotive forces of the power supply E4 and the power supply E5. For example, the potential V1 of the first electrode 6 is 10 kV, the potential V4 of the fourth electrode 74 is 7 kV, the potential V5 of the fifth electrode 75 is 4 kV, and the potential V3 of the third electrode 8 is 0 kV. SW4 and SW5 are fourth and fifth switches for turning on and off the connection between the fourth and fifth power sources E4 and E5 and the fourth and fifth electrodes 74 and 75, respectively. The switches SW1, SW4 and SW5 are opened and closed in conjunction with each other. The electric lines of force φ3 formed between the first electrode 6 and the third electrode 8 spread due to the influence of both the fourth electrode 74 and the fifth electrode 75. When the fifth electrode 75 is arranged in the vicinity of the third electrode 8, the spread is suppressed, and when the fifth electrode 75 is arranged in the vicinity of the fourth electrode 74, the fifth electrode 75 is formed to further spread. By adjusting the potential of the fifth electrode in this way, it is possible to adjust the spray range of the liquid fine particles. Note that the dispersion range of the liquid fine particles can also be adjusted by adjusting the potentials of the fourth electrode 74 and the fifth electrode. Other configurations and processing flow are the same as those in the first embodiment.

[Seventh Embodiment]
In the first embodiment, the nozzle 4 is a conductor, and the example in which the electrode 9 including the electrode connecting portion 6A and the nozzle 4 is used as the first electrode 6 and the liquid 9 in the nozzle 4 is charged is described. In the seventh embodiment, an example is shown in which the nozzle is made of an insulator, and the first electrode arranged in the vicinity of the entrance of the nozzle comes into contact with the liquid penetrating therethrough to charge the liquid into the nozzle.

  The nozzle 4 in the first embodiment (see FIG. 1) changes from a conductor to an insulator and does not constitute the first electrode, and only the electrode connection portion 6A constitutes the first electrode 6. The electrode connecting portion 6A comes into contact with the liquid 9 penetrating therethrough to make the liquid 9 charged, and the charged liquid 9 is fed into the nozzle 4. Even in this case, the liquid 9 discharged from the nozzle 4 is charged, and the presence of the second electrode 7 causes the liquid fine particles to be dispersed over a wide area on the surface of the object to be coated 2. In addition, the lines of electric force are guided not from the nozzle 4 but from the electrode connecting portion 6A toward the second electrode 7 and further toward the third electrode 8, and the liquid spraying path changes somewhat. To do. Other configurations and processing flow are the same as those in the first embodiment.

[Eighth Embodiment]
In the first embodiment, the object 2 is placed horizontally, the nozzle 4 is disposed vertically above the surface of the object 2, and the center of the object 2 is on the axis of the nozzle 4. However, in the eighth embodiment, the workpiece 2 is placed vertically, the nozzle 4 is arranged in the vertical direction of the surface of the workpiece 2, and the center of the workpiece 2 is the axis of the nozzle 4. An example on the line will be described.

  FIG. 9 shows a configuration example of a liquid coating apparatus 1D according to the seventh embodiment. Differences from the first embodiment will be mainly described. The configuration of the seventh embodiment is the same as the configuration of the first embodiment, that is, the arrangement of the coating object 2, the mounting table 3, the nozzle 4, and the first to third electrodes 6 to 8 in the vertical-horizontal plane. The structure is rotated by 90 ° (the horizontal direction and the vertical direction are switched). Therefore, the electric field lines are similarly rotated by 90 °. Other configurations and processing flow are the same as those in the first embodiment.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it is obvious that various modifications can be made to the embodiments.

  For example, in the first embodiment, the example in which the potentials of the first to third electrodes are set to V1> V2> V3 (= 0V) has been described, but V1 <V2 <V3 (= 0V) The polarity may be reversed, and the potential V3 of the third electrode may be set to other than 0V. In the first embodiment, the example in which the liquid is discharged from the nozzle after setting the potentials of the first to third electrodes has been described. However, after the potentials of the first to third electrodes are set, The liquid spraying range may be adjusted by discharging the liquid from the nozzle and then adjusting the potentials of the first and second electrodes. In the first embodiment, an example in which the nozzle is a conductor such as a metal has been described. However, the nozzle may be coated with an insulator. In the first embodiment, the example in which the power supply is arranged in parallel between the plurality of electrodes has been described. However, a configuration in which the power supply is arranged in series is also possible, and in the second embodiment, a resistance is provided between the plurality of electrodes. Although an example of arranging in series has been described, a configuration of arranging in parallel is also possible. In addition, the potential, installation position, dimensions, and the like of the first to third electrodes can be variously changed.

  The present invention can be used for liquid application, glass or lens coating, plating or paint application in the manufacture of semiconductor devices.

It is a figure which shows the structural example of the liquid application apparatus in 1st Embodiment. It is a figure which shows the difference of the electric force line by the presence or absence of a 2nd electrode. It is a figure which shows the example of a processing flow of the liquid application method in 1st Embodiment. It is a figure which shows the structural example of the liquid application apparatus in 2nd Embodiment. It is a figure which shows the structural example of the liquid application apparatus in 3rd Embodiment. It is a figure which shows the structural example of the 2nd electrode in 3rd Embodiment. It is a figure which shows the example of the shape of the 3rd electrode in 5th Embodiment. It is a figure which shows the structural example of the liquid application apparatus in 6th Embodiment. It is a figure which shows the structural example of the liquid application apparatus in 8th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A-1E Liquid application apparatus 2 To-be-coated object 3 Mounting stand 4 Nozzle 5 Operate valve 6 1st electrode 6A Electrode connection part 7 2nd electrode 7A 2nd electrode 7B which has a cover 2nd electrode main-body part 8, 8A Third electrode 9 Liquid fine particle 10 Electrode cover 74 Fourth electrode 75 Fifth electrode E1, E2 First and second power sources E4, E5 Fourth and fifth power sources SW1 to SW5 First to second 5 switches V1 to V5 potentials φ1, φ2, and φ3 of the first to fifth electrodes

Claims (7)

A liquid application device for applying a liquid to an object;
A mounting table for mounting the object to be coated;
A nozzle that is disposed opposite to the object to be coated placed on the mounting table and that discharges the liquid toward the object to be coated;
A first electrode for charging the liquid in the nozzle;
An annular second electrode disposed around the nozzle with the nozzle as a central axis;
A third electrode attached to the mounting table so as to apply a potential to the object to be coated;
The potential is set such that the potential of the second electrode is between the potential of the first electrode and the potential of the third electrode;
Liquid applicator. The lines of electric force from the first electrode to the third electrode spread radially outward from the nozzle and are formed so as to reach the third electrode after approaching the second electrode. ;
The liquid coating apparatus according to claim 1. A first resistor is provided between the first electrode and the second electrode, and a second resistor is provided between the second electrode and the third electrode;
The ratio of the potential difference between the first electrode and the second electrode and the potential difference between the second electrode and the third electrode is the resistance of the first resistor and the second resistor. Set by the ratio of values;
The liquid coating apparatus according to claim 1 or 2. A first power source is provided between the first electrode and the third electrode, and a second power source is provided between the second electrode and the third electrode;
The ratio of the potential difference between the first electrode and the second electrode and the potential difference between the second electrode and the third electrode is determined by the occurrence of the first power source and the second power source. Set by power ratio;
The liquid coating apparatus according to claim 1 or 2. The second electrode has at least the outer peripheral side and the end of the nozzle in the liquid discharge direction is covered with an insulator.
The liquid coating apparatus according to any one of claims 1 to 4. The second electrode is disposed at a predetermined length away from the tip of the discharge port on the side opposite to the liquid discharge direction.
The liquid coating apparatus according to claim 1. A liquid application method for applying a liquid to an object to be coated;
An object placement step of placing the object to be placed on a mounting table and arranging the object to be opposed to a nozzle that discharges the liquid toward the object to be coated;
A first electrode for charging the liquid in the nozzle to be charged; a second annular electrode disposed around the nozzle with the nozzle as a central axis; and a potential so as to apply a potential to the object to be coated. A potential setting step of setting a potential with respect to the third electrode attached to the mounting table so that the potential of the second electrode is between the potential of the first electrode and the potential of the third electrode. When;
A liquid spraying step of discharging the liquid from the nozzle toward the coating object and spraying the liquid in a spray form on the entire surface of the coating object;
Liquid application method.

Images