JP2008000718A - Liquid draining method for use in preparing thin film and apparatus for preparing thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid draining method to be employed in forming a thin film on a substrate using a dip coating method which enables the complete removal of a sagging liquid accumulating and sticking onto a lower edge of a substrate by air to help form a thin film of a uniform thickness on the substrate, and a method for preparing a thin film employing the above method. <P>SOLUTION: The liquid draining method to be employed in preparing a thin film for removing a sagging coating-liquid sticking to a substrate upon vertically pulling up a substrate 230 dipped in the coating liquid in the step of preparing a thin film using a dip coating method comprises the step of blowing air onto the substrate 230 being pulled up while properly adjusting the force of the air according to the position of the substrate 230 and the nature of the material thereof and the step of more strongly blowing air, upon detecting the lower edge 231 of the substrate 230, onto the lower edge 231 relative to the other part of the substrate 230. The apparatus 200 for preparing a thin film employs the above method. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a thin film by a dip coating method and a thin film manufacturing apparatus using the method, and more particularly, when a substrate immersed in a coating solution is pulled up vertically during the manufacturing process, the lower edge of the substrate The present invention relates to a liquid draining method and a thin film manufacturing apparatus using the method in thin film manufacturing that removes the sagging of coating liquid accumulated in the film.

  It is known to manufacture a thin film that can be used as a chemical filter or an organic EL display for removing a gas composed of low-concentration ammonia, acid, organic matter, etc. present in a clean room or a semiconductor manufacturing apparatus by a dip coating method. This dip coating method is a thin film manufacturing method classified as a wet process. Compared with a dry process in which a thin film is formed on a flat substrate by applying a high temperature in a vacuum, (1) the shape of the substrate is selected. There are no advantages, (2) it is inexpensive because it can be performed at room temperature and normal pressure, and (3) it can form a film with a large area.

  On the other hand, in the conventional dip coating method, when the substrate immersed in the coating solution is pulled up vertically, the solution accumulates at the lower edge of the substrate due to the action of gravity and surface tension as shown in FIGS. For this reason, air blow is applied to the substrate to drain off excess coating liquid (for example, see Patent Documents 1 and 2), or the substrate is tilted to drain the coating liquid (for example, Patent Documents). 3).

  In FIG. 2, a member indicated by reference numeral 30 is a substrate coated with a coating solution, and W represents a cross section of the coating. 3 is a cross-sectional view taken along line 3-3 in FIG. On the lower edge portion of the substrate 30, as shown by W 2, a coating liquid reservoir formed by the action of gravity and surface tension, that is, a sagging is formed.

JP 59-227771 A JP-A-4-94763 Japanese Patent Laid-Open No. 8-51268

  However, for example, as described in Patent Document 1 and Patent Document 2, the dip coating method in which an air blow is applied to a substrate to remove excess coating liquid, the air strength is insufficient, and the sagging of the coating liquid is completely eliminated. It has been pointed out that it cannot be removed, or air is applied too much to blow the necessary coating solution, resulting in a non-uniform thickness of the thin film produced.

  Further, for example, in the dip coating method in which the substrate is tilted and the coating solution is drained as described in Patent Document 3, the height of the coating solution in the coating solution tank, the height of the substrate, and the like are strict. Position management is required, and it is necessary to equip an inclination mechanism, a position detection mechanism, etc., and the apparatus is complicated. Moreover, it takes time to adjust the mechanism each time the dimensions of the substrate change.

  Further, the dip coating method using an uncharged coating solution is a dilute solution of polycation (cation) and polyanion (anion) on a substrate that is alternately adsorbed on a substrate, that is, a hydrophilic treatment (or hydrophobic treatment). By alternately immersing in the electrolyte, the electrolyte polymer is spontaneously adsorbed on the substrate, and organic molecules are assembled and organized by electrostatic force (Coulomb's force) generated by self-organization. It was extremely difficult.

  Accordingly, a first object of the present invention is to completely remove the sagging of the coating liquid accumulated on the lower edge portion of the substrate by air and to uniformly apply it to the substrate in the thin film production in which a thin film is formed on the substrate by the dip coating method. The present invention is to provide a method for running out of liquid in manufacturing a thin film to form a thin film having a suitable thickness and a thin film manufacturing apparatus using the method.

  In addition, the second object of the present invention is to provide a method for running out of a thin film capable of forming an alternately adsorbed film on a substrate in a dip coating method using an uncharged coating solution, and to produce a thin film using the method. Is to provide a device.

  The invention according to claim 1 is a liquid draining method in thin film manufacturing that removes dripping of the coating liquid adhering to the substrate when the substrate immersed in the coating liquid is pulled up vertically in the process of manufacturing the thin film by the dip coating method. Depending on the position of the substrate during the pulling operation and the material of the substrate, the air strength is adjusted and blown, and when the lower edge of the substrate is detected, the lower edge is compared to other parts. The first object is achieved by blowing strong air.

  The invention according to claim 2 achieves the second object by charging the air to be sprayed positively or negatively in addition to the method of the invention according to claim 1.

  According to a third aspect of the present invention, there is provided a thin film manufacturing apparatus comprising a liquid draining means for removing dripping of the coating liquid adhering to the substrate when the substrate immersed in the coating liquid is pulled up in the course of manufacturing the thin film by the dip coating method. According to the position of the substrate during the pulling operation and the material of the substrate, the liquid draining means adjusts the strength of air and sprays it, and when detecting the lower edge of the substrate, the lower edge The first object is achieved by blowing stronger air than the other parts.

  According to a fourth aspect of the present invention, in addition to the configuration of the third aspect of the invention, the second object is achieved by charging the air to be sprayed positively or negatively.

According to the first aspect of the present invention, when the substrate immersed in the coating solution is pulled up vertically in the process of manufacturing the thin film by the dip coating method, the draining method in the thin film manufacturing removes the sagging of the coating solution adhering to the substrate. Then, by adjusting the strength of the air and spraying according to the position of the substrate and the material of the substrate during the pulling operation,
(1) Since a uniform film according to the material of the substrate can be formed on the surface of the substrate, the quality of the formed thin film is improved. Also,
(2) When the lower edge of the substrate is detected, strong air is blown to the lower edge compared to other parts, so that it accumulates on the lower edge of the substrate due to the action of gravity and surface tension. Since the coating solution can be removed, the quality of the thin film is further improved.

  According to the invention according to claim 2, in addition to the effect of the invention according to claim 1, by charging the air to be sprayed positively or negatively, the coating liquid that is not charged at the same time as the draining is applied on the substrate. Since it can be charged positively or negatively, for example, film formation using an electric charge such as an alternating adsorption film can be made efficient.

According to the third aspect of the invention, there is provided the liquid draining means for removing the sagging of the coating solution adhering to the substrate when the substrate immersed in the coating solution is pulled up vertically in the process of manufacturing the thin film by the dip coating method. In the thin film manufacturing apparatus, the liquid draining means adjusts the strength of air according to the position of the substrate during the pulling operation, the material of the substrate, etc. and sprays it, and detects the lower edge of the substrate. , By blowing strong air at the lower edge compared to other parts,
(1) Since a uniform film according to the material of the substrate can be formed on the surface of the substrate, the quality of the formed thin film is improved. Also, when detecting the lower edge of the substrate, by blowing strong air compared to other parts on the lower edge,
(2) Since the coating liquid accumulated on the lower edge of the substrate can be removed by the action of gravity and surface tension, the quality of the thin film is further improved. further,
(3) Since the substrate pulling operation originally provided in the apparatus is used, the position of the air outlet can be fixed regardless of the size of the substrate.

  According to the invention of claim 4, in addition to the effect of the invention of claim 3, it has the air charging means for charging the air to be sprayed positively or negatively. Since the coating liquid that has not been charged can be charged positively or negatively on the substrate, for example, film formation using charges such as the alternating adsorption film described above can be made efficient.

  An example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 schematically illustrates the configuration of a thin film manufacturing apparatus 100 used in the liquid running out method in the thin film manufacturing of the present invention. A member denoted by reference numeral 112 indicates an immersion tank in which the coating liquid 120 is stored. The member denoted by reference numeral 130 is a substrate to be dipped. The substrate 130 is held by a substrate holder 140 and is connected to a substrate support bar 152 extending from the elevating nut 150.

  The elevating nut 150 is screwed to the screw shaft 160 via a ball (not shown) to form a so-called “ball screw”. Therefore, it is possible to feed at high speed with low friction compared to the case of using a “slide screw” that generates a feed function by utilizing the slip between the thread surfaces of the male screw and the female screw.

  A driven gear 164 is fixed to the upper end portion of the screw shaft 160 and is screwed with a drive gear 162 fixed to the rotating shaft 172 of the lifting motor 170. An encoder 174 that accurately measures the rotational speed, rotational speed, and the like of the lifting motor 170 is installed on the rotating shaft on the opposite side of the rotating shaft 172 of the lifting motor 170. The encoder output signal S1 from the encoder 174 is sent to the controller 175 to sequentially control the air flow rate according to the size of the board, the material of the board, the position of the board, etc. stored in the memory in the controller 175. A flow rate control signal S3 for performing is transmitted to the flow rate control means 176. For example, when the flow rate control means 176 receives the flow rate control signal S3 from the controller 175 that the lower edge portion 131 of the substrate 130 is at the position of the air outlet 180, it is formed at the lower edge portion 131 of the substrate 130. Control is performed to increase the air flow rate in order to blow off the liquid pool, that is, the sauce.

  Whether the lower edge portion 131 of the substrate 130 is at the position of the air outlet 180 can be detected by installing a sensor in the vicinity of the air outlet 180, as in this embodiment. By detecting using the output of the encoder 174, the apparatus configuration can be simplified. In this embodiment, since the air jet outlet 180 is provided at a position where the lower edge portion 131 of the substrate 130 passes during the pulling operation of the substrate 130, even if the air jet outlet 180 is fixed, The solution at the edge 131 can be removed. The main purpose of the air jet outlet 180 is to remove the sagging formed at the lower edge portion 131 of the substrate 130, so the air jet outlet 180 allows air to flow in an obliquely downward direction opposite to the pulling direction of the substrate 130. Erupts. This point is fundamentally different from the technical matters described in Patent Documents 1 to 3 cited as the prior art in the problems, configurations, and effects of the invention.

  Further, when the substrate 130 is being lifted, the flow rate of air is adjusted in accordance with the position of the substrate and the material of the substrate, and control is performed so that there is no excess or deficiency. For example, the air strength is adjusted by increasing the air amount when the substrate 130 to be used is hard, and decreasing the air amount when the substrate 130 is soft. Further, when the substrate 130 is not present at the air outlet 180, the flow rate control means 176 controls to turn off the air blowing. A weak air is blown onto the upper portion of the substrate 130 to dry the substrate, and a strong air is blown onto the lower edge portion 131 of the substrate 130 to remove a liquid pool, that is, sagging. Since the speed at which the substrate 130 is lifted is also related to the efficiency of liquid removal, the control signal S2 is fed back from the controller 175 to the lifting / lowering motor 170 to control the lifting speed of the substrate 130.

  The flow rate control means 176 receives the air supply G1 and receives a flow rate control signal S3 from the controller 175 to supply a predetermined amount of air G2 to the air jet outlet 180. Further, if necessary, the air can be charged positively or negatively by the air charging means 178 before being supplied to the air ejection port 180 (corresponding to claims 2 and 4). As a result, it is possible to easily form an alternating adsorption film made of one type of coating solution, which has been extremely difficult until now by the dip coating method using a single dip bath. The specific mechanism of the air charging unit 178 is not particularly limited. For example, a commercially available ionizer that can control and monitor the ion balance is preferably used.

  Next, another embodiment of the present invention will be described with reference to FIG.

  FIG. 4 schematically shows the configuration of a thin film manufacturing apparatus 200 which is another embodiment used in the liquid running method in the thin film manufacturing of the present invention. In this embodiment, a plurality of immersion tanks 212 constitute the immersion tank group 210, and the substrate 230 can be immersed in a plurality of different coating solutions 220 in order by the X-axis linear slider 262 and the Y-axis linear slider 260. It is possible. The substrate 230 is held by a substrate holder 240 and connected to a substrate support bar 252 extending from the elevating nut 250. The mechanisms of the X-axis linear slider 262 and the Y-axis linear slider 260 are not particularly limited. For example, a general-purpose linear slider used for a welding robot or the like is preferably used.

  Although not shown, an elevating motor is mounted on the upper end portion of the Y-axis linear slider 260, and a drive gear is fixed to the rotating shaft. Further, a ball screw is housed inside the Y-axis linear slider, and a driven gear that is screwed to the drive gear is fixed to the upper end of the ball screw. Although not shown, the X-axis linear slider 262 is internally provided with a ball screw for moving the Y-axis linear slider 260 to the left and right, and is equipped with a traveling motor at one end thereof. An encoder that accurately measures the rotational speed and rotational speed of the lifting motor is installed on the rotating shaft opposite to the main rotating shaft of the lifting motor. The encoder output signal S4 from the encoder is sent to the controller 275 to sequentially control the air flow according to the size of the substrate, the material of the substrate, the position of the substrate, etc. stored in the memory in the controller 275. The flow rate control signal S6 is transmitted to the flow rate control means 276.

  For example, when the flow rate control means 276 receives the flow rate control signal S6 from the controller 275 that the lower edge portion 231 of the substrate 230 is at the position of the air outlet 280, it is formed at the lower edge portion 231 of the substrate 230. In order to blow off the liquid pool, that is, the sagging, control is performed to increase the air flow rate. On the other hand, when the upper portion of the substrate 230 is moving up the air outlet 280, the flow of air is controlled to dry the substrate 230.

  Further, when the substrate 230 is being pulled up, the flow rate of air is adjusted according to the position of the substrate 230, the material of the substrate 230, and the like, and control is performed so that there is no excess or deficiency. Since the speed at which the substrate is pulled up is also related to the efficiency of liquid drainage, the controller 275 feeds back a control signal S5 to a lifting motor (not shown) to control the lifting speed of the substrate 230.

  Further, the flow rate control means 276 receives the air supply G3, and receives a flow rate control signal S6 to supply a desired amount of air G4 to the air outlet 280. Further, if necessary, the air can be charged positively or negatively by the air charging means 278 before being supplied to the air ejection port 280. In the present invention, after applying an uncharged coating solution 220 to the substrate 230, charged air is blown to charge the coating film on the substrate 230, so that the substrate is immersed in a dilute solution of polycation and polyanion alternately. Unlike the alternating adsorption method, in which the electrolyte polymer is spontaneously adsorbed on the top and self-organized, the charge does not escape from the coating liquid 220 in the coating tank 212, so that an alternate adsorption film can be produced efficiently. It is.

  Since the present invention can use an existing elevating device, XY moving device, etc. without requiring a new actuator, the device can be constructed at a low cost. It can be applied to the production of ultra-thin films, and its industrial applicability is extremely high.

The schematic diagram which showed the apparatus structure of Example 1 of this invention. The conceptual diagram which shows a film when a board | substrate is immersed in a coating liquid. Sectional drawing when the board | substrate of FIG. 2 is cut | disconnected by 3-3 line. The schematic diagram which showed the apparatus structure of Example 2 of this invention.

Explanation of symbols

100, 200 ... Thin film manufacturing apparatus 112, 212 ... Immersion tank 120, 220 ... Coating solution 30, 130, 230 ... Substrate 131, 231 ... Lower edge part 140, 240 (of substrate) ... Substrate holders 150, 250 ... Elevating nuts 152, 252 ... Substrate support rod 160 ... Screw shaft 162 ... Drive gear 164 ... Follower gear 170 ... Elevating motor 172 Rotating shaft 174 Encoders 175, 275 Controllers 176, 276 Flow control means 178, 278 Air charging means 180, 280 Air outlet 260 ... Y-axis linear Slider 262 ... X-axis linear slider G1, G2, G3, G4 ... Air flow S1, S4 ... Encoder output signals S2, S5 ... Control Signal S3, S6 ... Flow control signal

Claims (4)

In the process of producing a thin film by a dip coating method, when the substrate immersed in the coating liquid is pulled up vertically, the liquid draining method in the thin film production to remove the sagging of the coating liquid adhering to the substrate,
Depending on the position of the substrate during the pulling operation and the material of the substrate, the air strength is adjusted and sprayed, and when the lower edge portion of the substrate is detected, the lower edge portion is compared with other portions. Then, a liquid draining method in thin film production, characterized in that strong air is blown.   2. The liquid draining method in thin film production according to claim 1, wherein the air to be sprayed is charged positively or negatively. A thin film manufacturing apparatus provided with a liquid draining means for removing the sagging of the coating liquid adhering to the substrate when the substrate immersed in the coating liquid is pulled up vertically in the process of manufacturing the thin film by a dip coating method,
According to the position of the substrate during the pulling operation and the material of the substrate, the liquid breakage means adjusts the strength of air and sprays the lower edge portion when detecting the lower edge portion of the substrate. A thin film manufacturing apparatus characterized in that air is blown stronger than other parts.   4. The thin film manufacturing apparatus according to claim 3, further comprising air charging means for charging the air to be sprayed positively or negatively.

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