JP2015115462A - Coating apparatus and coating method - Google Patents

Abstract

There is provided a coating apparatus capable of forming a coating film on the entire coating object even when a high step or an opening with a large aspect ratio is formed on the surface of the coating object.
A coating apparatus 1 according to one aspect of the present invention has a heating unit 20 that heats an application target object 50, and a surface 50a of the application target object 50 that is heated by the heating unit 20. Spraying means 10 for spraying the particulate coating liquid 15.
[Selection] Figure 1

Description

  The present invention relates to a coating apparatus and a coating method.

  As a method for applying a coating solution to the surface of an object to be applied, methods described in Patent Documents 1 to 3 are known. In this coating method, the coating liquid supplied to the nozzle is atomized by electrostatic force and sprayed onto the coating object. For example, in the coating methods described in Patent Documents 1 and 2, a voltage is applied between the nozzle and the counter electrode, and an electrostatic attractive force exceeding the surface tension is applied to the meniscus formed at the tip of the nozzle. The coating liquid supplied to the tip of the nozzle is attracted to the outside of the nozzle by this electrostatic attraction. The coating liquid attracted from the tip of the nozzle flies in a string shape, eventually splits and atomizes, and is sprayed onto the coating object. The shape in which the coating liquid flies is a single liquid column that is continuous from the tip of the nozzle. The liquid columnar coating liquid eventually scatters as a group of liquid fine particles and adheres to the object to be coated. Therefore, there is little scattering of the coating liquid to the periphery, and this is a method with good coating efficiency.

JP 2011-251254 A JP 2008-246353 A JP 2008-93619 A

  The use of the above method as a method of applying a resist to the surface of a semiconductor substrate has been studied. However, there are cases where high steps or openings with a large aspect ratio (hereinafter referred to as “steps”) are formed on the surface of the semiconductor substrate, and a resist is formed on the surface of these steps, etc. without any breaks. Was difficult. In particular, corner portions such as steps have a tendency to reduce the resist film thickness, and if a resist break occurs at this portion, the subsequent etching is adversely affected.

  An object of the present invention is to provide a coating apparatus and a coating method capable of forming a coating film on the entire coating object without any break even when a step or the like is formed on the surface of the coating object. is there.

  A coating apparatus according to an aspect of the present invention includes a heating unit that heats an application target, and a spray unit that sprays a charged particulate coating liquid onto one surface of the coating target heated by the heating unit. And comprising.

  According to this configuration, the solute or dispersoid in the coating liquid can be reliably deposited in the vicinity of the position where the coating liquid adheres by drying the coating liquid adhered to the coating object by heating.

  For example, when a step or the like is formed on one surface of the application target, a part of the sprayed coating liquid adheres to a corner portion such as a step. At this time, if the coating liquid is continuously sprayed without heating the object to be coated, the fine-particle coating liquid adhering to the corners is bonded to each other to form a liquid film and is greatly increased around the corners by its own weight. Spread wet. Therefore, it is difficult to form a solute or dispersoid film (coating film) at the corners.

  On the other hand, when the application liquid is sprayed in a state where the object to be applied is heated, the fine particle application liquid adhering to the corners is dried before the surroundings are greatly wetted and spread. Therefore, the solute or dispersoid in the coating solution is likely to be deposited near the adhesion position. Therefore, it is possible to form a coating film on the entire coating object without any breaks.

  In the coating apparatus which concerns on 1 aspect of this invention, the temperature adjustment means which adjusts the heating temperature of the said target object by the said heating means can be included.

  According to this configuration, the temperature of the coating object can be appropriately controlled according to the boiling point of the coating liquid, the wettability of the coating object, and the like.

  In the coating apparatus according to an aspect of the present invention, the spraying unit includes a nozzle to which the coating liquid is supplied, a counter electrode provided to face the nozzle, and a gap between the nozzle and the counter electrode. And voltage applying means for applying a voltage such that the coating liquid supplied to the nozzle is atomized.

  According to this configuration, the coating liquid can be sprayed linearly by the electric field between the nozzle and the counter electrode. Therefore, even if an opening having a large aspect ratio exists on one surface of the application target, the coating liquid can be reliably applied to the back of the opening.

  In the coating apparatus which concerns on 1 aspect of this invention, the moving means which moves the said nozzle and the said coating target object relatively can be included.

  According to this configuration, even when the application object is large, the entire application object can be applied uniformly.

  A coating method according to an aspect of the present invention includes a heating step of heating a coating target, and a spraying step of spraying a charged particulate coating liquid on one surface of the coating target heated by the heating step. And including.

  According to this configuration, the solute or dispersoid in the coating liquid can be reliably deposited in the vicinity of the position where the coating liquid adheres by drying the coating liquid adhered to the coating object by heating.

  For example, when a step or the like is formed on one surface of the application target, a part of the sprayed coating liquid adheres to a corner portion such as a step. At this time, if the coating liquid is continuously sprayed without heating the object to be coated, the fine-particle coating liquid adhering to the corners is bonded to each other to form a liquid film and is greatly increased around the corners by its own weight. Spread wet. Therefore, it is difficult to form a solute or dispersoid film (coating film) at the corners.

  On the other hand, when the application liquid is sprayed in a state where the object to be applied is heated, the fine particle application liquid adhering to the corners is dried before the surroundings are greatly wetted and spread. Therefore, the solute or dispersoid in the coating solution is likely to be deposited near the adhesion position. Therefore, it is possible to form a coating film on the entire coating object without any breaks.

  In the coating method according to an aspect of the present invention, in the heating step, the coating object can be heated to a temperature of 30 ° C. or higher and 100 ° C. or lower.

  As described above, the uniformity of the coating film formed on one surface of the coating object and the thickness of the coating film formed at the corners such as steps vary depending on the temperature of the coating object when spraying the coating liquid. To do. When the temperature of the coating object is high, wetting and spreading of the coating solution is suppressed, so that the thickness of the coating film formed at corners such as steps increases, but the thickness of the coating film tends to be uneven. On the other hand, when the temperature of the object to be applied is low, the coating solution tends to wet and spread, so that the uniformity of the coating film is increased, but the thickness of the coating film formed at the corners such as steps is likely to be small.

  In this coating method, the thickness of the coating film formed on one surface of the coating object can be made uniform using such properties. For example, when the temperature of the object to be applied is higher than 100 ° C., wetting and spreading of the coating liquid hardly occur, and the thickness unevenness of the coating film increases. On the other hand, if the temperature of the object to be applied is lower than 30 ° C., the spreading of the coating liquid becomes large, and a coating film having a sufficient thickness cannot be formed at corners such as steps. By controlling the temperature of the object to be applied in the range of 30 ° C. or more and 100 ° C. or less, it is possible to form a coating film having a sufficient thickness at corners such as steps while suppressing uneven thickness of the coating film.

  In the coating method according to an aspect of the present invention, the spraying step includes a coating liquid supply step for supplying the coating liquid to a nozzle, a nozzle, and a counter electrode provided to face the nozzle. And a voltage applying step of applying a voltage such that the coating liquid supplied to the nozzle is finely divided.

  According to this configuration, the coating liquid can be sprayed linearly by the electric field between the nozzle and the counter electrode. Therefore, even if an opening having a large aspect ratio exists on one surface of the application target, the coating liquid can be reliably applied to the back of the opening.

  The coating method according to another aspect of the present invention includes: a first temperature control step for heating a coating object to control the temperature of the coating object to a first temperature; and the first temperature control step. A first spraying step of spraying a charged particulate coating liquid onto one surface of the coating target controlled to a first temperature, and the coating liquid sprayed by the first spraying step A second temperature control step for controlling the temperature of the application object to a second temperature lower than the first temperature; and the application object controlled to the second temperature by the second temperature control step. And a second spraying step of spraying the charged particulate coating solution on one surface.

  According to this configuration, first, in the first spraying step, the coating liquid is sprayed in a state where the application target is controlled to a relatively high temperature (first temperature). Thereby, the 1st application layer of sufficient thickness is formed in corners, such as a level difference. In the second spraying step, the coating liquid is sprayed in a state where the application target is controlled to a relatively low temperature (second temperature). As a result, the coating liquid sprayed in the second spraying step adheres to the surface of the first coating layer, and the thickness spreads out the unevenness of the thickness on the surface of the first coating layer by spreading it wet. The second coating layer is formed. Therefore, the thickness of the coating film formed by the first coating layer and the second coating layer is uniform.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where the level | step difference etc. are formed in the surface of a coating target object, the coating apparatus and coating method which can form a coating film on the whole coating target object seamlessly are provided. it can.

It is a figure which shows schematic structure of the coating device which concerns on 1st embodiment of this invention. It is a figure which shows the coating method which concerns on 1st embodiment of this invention. It is a figure which shows the mechanism in which a coating film is formed in one surface of a coating target object. It is a figure which shows the coating method which concerns on 2nd embodiment of this invention.

[First embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 is a diagram showing a schematic configuration of a coating apparatus 1 according to the first embodiment of the present invention.
The coating apparatus 1 according to this embodiment includes a spray unit 10, a heating unit 20, and a temperature adjusting unit 30.

  The spraying means 10 sprays the charged fine particulate coating liquid 15 onto the one surface 50 a of the coating target 50. As the spraying method, known spraying methods such as an air atomizing method, an airless atomizing method, and an electrostatic atomizing method can be used. The air atomization method is a method in which a coating liquid is sprayed with compressed air to form fine particles, and an electric charge is imparted to the finely divided coating liquid. The airless atomization method is a method in which a coating liquid is ejected by mechanical pressure to form fine particles, and an electric charge is applied to the finely divided coating liquid. The electrostatic atomization method is a method in which a coating liquid is finely divided by electrostatic force, and the finely divided and charged coating liquid is sprayed by Coulomb force.

  For example, a semiconductor wafer, a glass substrate, a plastic substrate, or the like is used as the application object 50, but the application object 50 is not limited to this. The surface 50a of the application target 50 to which the coating liquid 15 is applied may be provided with a high step or an opening having a large aspect ratio (hereinafter referred to as “step or the like”).

  In the present embodiment, for example, an electrostatic atomization method is used as the spray means 10. The electrostatic atomization method has less scattering of the coating liquid 15 to the surroundings compared to the air atomization method and the airless atomization method. In addition, since the coating solution 15 has high straightness, the coating solution 15 can be applied to the back of the opening even if there is an opening with a high aspect ratio on the one surface 50a of the coating object 50.

  The spraying unit 10 includes, for example, a nozzle 11, a counter electrode 12, a voltage applying unit 13, and a moving unit 14.

  The nozzle 11 is made of a conductive material. A coating liquid is supplied to the nozzle 11 from a coating liquid tank (not shown) via a syringe pump. The discharge amount of the coating liquid discharged from the nozzle 11 is stably controlled by a syringe pump, for example, in the range of 0.001 to 0.1 ml / min, preferably in the range of 0.005 to 0.05 ml / min. Is done. The counter electrode 12 is provided to face the nozzle 11 at a position spaced apart from the tip of the nozzle 11 vertically downward by a predetermined distance. The counter electrode 12 is formed, for example, by bending a single rod-like electrode into a substantially C shape, and a gap for allowing the coating liquid attracted from the nozzle 11 to pass between both ends of the counter electrode 12. Is provided. The configuration of the counter electrode 12 is not limited to this as long as it does not prevent the coating liquid 15 from flying.

  The voltage applying means 13 applies a voltage between the nozzle 11 and the counter electrode 12 so that the coating liquid supplied to the nozzle 11 is made into fine particles. For example, the voltage applying unit 13 applies a voltage using the nozzle 11 as a negative electrode and the counter electrode 12 as a positive electrode. The magnitude of the voltage is, for example, 1 kV to 10 kV. By making the magnitude | size of a voltage into this range, the average particle diameter (D32) of the coating liquid 15 can be controlled in 1-20 micrometers and an average particle speed in the range of 0.1-10 m / s. The nozzle 11 may be a positive electrode and the counter electrode 12 may be a negative electrode.

  The voltage application means 13 applies a voltage between the nozzle 11 and the counter electrode 12 to cause an electrostatic attraction force exceeding the surface tension to act on the meniscus formed at the tip of the nozzle 11. The coating liquid supplied to the tip of the nozzle 11 is attracted to the outside of the nozzle 11 by this electrostatic attraction force. The coating liquid attracted from the tip of the nozzle 11 flies in a string shape, and is eventually split and atomized and sprayed onto the coating object 50. The shape in which the coating liquid flies is a single liquid column that is continuous from the tip of the nozzle 11. The liquid column-shaped coating liquid eventually scatters as a liquid fine particle group and adheres to the coating object 50.

  The moving means 14 relatively moves the application object 50 and the nozzle 11 in a direction parallel to the one surface 50 a of the application object 50. From the nozzle 11, the coating liquid 15 is sprayed linearly toward the coating object 50. The moving unit 14 relatively moves the nozzle 11 and the application target object 50 so that the application is performed on the entire application target area of the application target object 50.

  The heating means 20 heats the application target object 50. The heating temperature of the application object 50 by the heating means 20 is variably adjusted by the temperature adjusting means 30. The spraying means 10 sprays the charged particulate coating solution 15 onto the one surface 50 a of the coating object 50 heated by the heating means 20. For example, a hot plate is used as the heating unit 20, but the heating unit 20 is not limited to this. As the heating means 20, one that heats the application target 50 by irradiating the application target 50 with infrared rays or microwaves may be used.

  FIG. 2 is a diagram showing a coating method according to the first embodiment of the present invention. FIG. 3 is a diagram showing a mechanism by which a coating film is formed on one surface 50a of the coating object 50. As shown in FIG.

  As shown in FIG. 2, in the coating method of the present embodiment, a heating step S1 for heating the coating target object 50 and a surface 50a of the coating target object 50 heated by the heating step S1 are charged with fine particles. Spraying step S <b> 2 for spraying the coating liquid 15.

  In the present embodiment, the solute or dispersoid in the coating liquid 15 can be reliably deposited in the vicinity of the position where the coating liquid 15 is adhered by drying the coating liquid 15 adhered to the coating object 50 by heating.

  For example, as shown in FIG. 3A, when a step 51 or the like is formed on one surface 50 a of the application target 50, a part of the sprayed coating solution 15 adheres to the corner 51 a of the step 51 or the like. . At this time, if the coating solution 15 is continuously sprayed without heating the coating object 50, the particulate coating solution 15 adhering to the corners 51a is bonded to each other to form a liquid film 16, and the corners due to its own weight. It spreads greatly around the part 51a. Therefore, a solute or dispersoid film (coating film: a film obtained by drying or curing the film 16) is hardly formed on the corner 51a.

  On the other hand, as shown in FIG. 3B, when the coating liquid 15 is sprayed in a state where the coating object 50 is heated, the particulate coating liquid 15 adhering to the corner 51a is dried before it is largely wet and spreads around. To do. Therefore, the solute or dispersoid in the coating liquid 15 is likely to be deposited near the adhesion position. Therefore, the coating film 17 can be formed on the entire coating object 50 without any breaks.

  In the heating step S1, the application object 50 is heated to the first temperature T1 by the heating means 20. For example, the application object 50 is transported to and installed in the heating means 20 (hot plate or the like) set to the first temperature T1. In the spraying step S2, the coating liquid 15 is sprayed on the one surface 50a of the coating object 50 in a state where the temperature of the coating object 50 is raised to the first temperature T1. For example, the first temperature T1 is preferably 30 ° C. or higher and 100 ° C. or lower.

  As described above, the uniformity of the coating film 17 formed on the one surface 50a of the coating object 50 and the thickness of the coating film 17 formed on the corner 51a of the step 51 or the like are determined when the coating liquid 15 is sprayed. It changes depending on the temperature of the application object 50. When the temperature of the coating object 50 is high, wetting and spreading of the coating solution 15 is suppressed, so that the thickness of the coating film 17 formed on the corner 51a of the step 51 or the like increases, but the thickness of the coating film 17 is not uniform. It is easy to become. On the other hand, when the temperature of the coating object 50 is low, the coating solution 15 is likely to spread and spread, so that the uniformity of the coating film 17 is increased. However, the thickness of the coating film 17 formed on the corner 51a of the step 51 or the like is small. Prone.

  In this coating method, the thickness of the coating film 17 formed on the one surface 50a of the coating object 50 can be made uniform using such properties. For example, when the temperature of the object 50 to be applied is higher than 100 ° C., the wetting and spreading of the coating liquid 15 hardly occurs, and the thickness unevenness of the coating film 17 increases. On the other hand, when the temperature of the coating object 50 is lower than 30 ° C., the spreading of the coating solution 15 increases, and the coating film 17 having a sufficient thickness cannot be formed on the corner 51a of the step 51 or the like. If the temperature of the coating object 50 is controlled within the range of 30 ° C. or more and 100 ° C. or less, the coating film 17 having a sufficient thickness is formed on the corner 51a of the step 51 or the like while suppressing the uneven thickness of the coating film 17. Can do.

  The optimum temperature for achieving both the uniformity of the coating film 17 and the coverage of the corners 51a varies depending on the boiling point of the coating solution 15, the wettability of the coating object 50 (affinity with the coating solution 15), and the like. . Therefore, in the heating step S <b> 1, it is preferable to adjust the heating temperature of the application object 50 by the temperature adjusting means 30. Thereby, the temperature of the coating object 50 can be appropriately controlled according to the boiling point of the coating liquid, the wettability of the coating object 50, and the like.

  Note that the temperature of the application object 50 need not always be fixed at a constant temperature during the period of spraying the application liquid 15. The temperature of the application object 50 may vary during the period in which the application liquid 15 is sprayed. The spraying of the coating liquid 15 may be performed in a state where the temperature of the coating target 50 is higher than the temperature around the coating target 50 (room temperature, for example, 25 ° C.). It is not always necessary to continue heating with the heating means 20. For example, heating by the heating unit 20 may be stopped while the coating liquid 15 is being sprayed.

  The spraying step S <b> 2 includes, for example, the coating liquid supplied to the nozzle 12 between the coating liquid supply step for supplying the coating liquid to the nozzle 11 and the nozzle 11 and the counter electrode 12 provided to face the nozzle 11. And a voltage applying step for applying a voltage such that the liquid is atomized.

  According to this configuration, the coating liquid 15 can be sprayed linearly by the electric field between the nozzle 11 and the counter electrode 12. Therefore, even if an opening having a large aspect ratio exists on one surface 50a of the application object 50, the coating liquid 15 can be reliably applied to the depth of the opening.

  As described above, in the coating apparatus 1 and the coating method of the present embodiment, the charged fine particle coating solution 15 is sprayed on the one surface 50a of the coating target 50 while the coating target 50 is heated. . Therefore, even when a step 51 or the like is formed on the surface of the application target 50, the coating film 17 can be formed on the entire application target 50 without any breaks.

  In the present embodiment, since a high voltage is applied to the coating solution 15 to form fine particles, the average particle size (D32) of the coating solution 15 is very small, and variations in the maximum particle size and standard deviation (RMS) are also small. Therefore, uniform film formation on the coating object 50 is possible. Further, no carrier gas is used when spraying the coating liquid 15. Only the discharge pressure from the nozzle 11 and the Coulomb force acting between the nozzle 11 and the counter electrode 12 act on the coating solution 15. For this reason, the speed of the coating liquid 15 from the nozzle 11 toward the coating object 50 becomes very slow. Accordingly, the winding of the coating liquid 15 that rebounds on the surface of the coating object 50 is reduced, and the surface of the step 51 or the like can be reliably applied.

  For example, when comparing the electrostatic atomization method of the present embodiment that does not use air to supply the liquid and the rotary atomization method that uses air to supply the liquid, the particle size of the liquid and the liquid particle The supply speed is different as follows. In addition, the following numerical values are values when ethanol is used as the liquid. The inner diameter of the nozzle is 0.34 mm, and the inclination angle of the end surface on the tip side of the nozzle with respect to the nozzle center axis is 30 °.

<Electrostatic atomization method>
-Particle diameter D32 ... 10.65 μm
・ Particle size MAX: 13.21 μm
・ Particle diameter MIN: 2.47 μm
・ Particle flight speed (AVE): 1.11 m / s

<Rotating atomization method>
-Particle diameter D32 ... 15.82 μm
-Particle size MAX ... 30.70 μm
・ Particle size MIN: 6.10 μm
・ Particle flight speed (AVE): 19.66 m / s

  “D32” means Sauter Mean Diameter (SMD). “D32” means a particle size having the same surface area to volume ratio as the total volume of all particles relative to the total surface area of all particles. “Particle size MAX” means the maximum particle size. “Particle size MIN” means the minimum particle size. “Particle flight speed (AVE)” means a simple average of the flight speed of liquid particles.

  As described above, in the electrostatic atomization method used in the present embodiment, the values of the particle diameter D32, the particle diameter MAX, the particle diameter MIN, and the particle flight speed (AVE) are all smaller than those of the rotary atomization method. . The numerical values described above are the results of using ethanol as the liquid, but it is expected that similar results will be obtained even when other liquids such as resist are used. Therefore, it can be seen that the electrostatic atomization method is an excellent method as an application method to a step or the like.

[Second Embodiment]
FIG. 4 is a diagram showing a coating method according to the second embodiment of the present invention.
In the coating method of the present embodiment, the first temperature control step S11 for heating the coating object 50 and controlling the temperature of the coating object 50 to the first temperature T1 and the first temperature control step S11 are the first. The coating liquid 15 is sprayed by the first spraying step S12 for spraying the charged particulate coating liquid 15 on the one surface 50a of the coating target 50 controlled to the temperature T1, and the first spraying step S12. The second temperature control step S13 for controlling the temperature of the coated object 50 to the second temperature T2 lower than the first temperature T1, and the second temperature control step S13 controlled the second temperature T2. And a second spraying step S14 of spraying a charged particulate coating solution 15 on one surface 50a of the coating object 50.

  In the first temperature control step S11, the application object 50 is heated to the first temperature T1 by the heating means 20. For example, the application object 50 is transported to and installed in the heating means 20 (hot plate or the like) set to the first temperature T1. In the first spraying step S <b> 12, the coating liquid 15 is sprayed on the one surface 50 a of the coating target object 50 in a state where the temperature of the coating target object 50 is raised to the first temperature T <b> 1. For example, the first temperature T1 is preferably 30 ° C. or higher and 100 ° C. or lower.

  In the second temperature control step S13, the temperature of the application object 50 is controlled to a second temperature T2 lower than the first temperature T1 by lowering the heating temperature of the heating means 20 or stopping the heating. The application target object 50 is installed, for example, on the heating means 20 (hot plate or the like) set to the second temperature T1. In the second spraying step S14, the coating liquid 15 is sprayed on the one surface 50a of the coating object 50 in a state where the temperature of the coating object 50 is lowered to the second temperature T2.

  According to this configuration, first, in the first spraying step S12, the coating liquid 15 is sprayed in a state where the coating object 50 is controlled to a relatively high temperature (first temperature T1). Thereby, a first coating layer having a sufficient thickness is formed on the corner 51a of the step 51 or the like. In the second spraying step S14, the coating liquid 15 is sprayed in a state where the coating object 50 is controlled to a relatively low temperature (second temperature T2). Thereby, the coating liquid 15 sprayed in the second spraying step S14 adheres to the surface of the first coating layer, and this spreads out so that the unevenness of the thickness is offset on the surface of the first coating layer. A second coating layer having a sufficient thickness is formed. Therefore, the thickness of the coating film 17 formed by the first coating layer and the second coating layer is uniform.

  In the first spraying step S <b> 12, the temperature of the application object 50 does not have to be fixed at a constant temperature during the period during which the coating liquid 15 is sprayed. The temperature of the application object 50 may vary during the period in which the application liquid 15 is sprayed. In the first spraying step S12, the spraying of the coating liquid 15 may be performed in a state where the temperature of the coating target 50 is higher than the temperature around the coating target 50 (room temperature, for example, 25 ° C.). It is not always necessary to continue heating with the heating means 20 during the period of spraying the liquid 15. For example, heating by the heating unit 20 may be stopped while the coating liquid 15 is being sprayed.

  In the second spraying step S <b> 14, the temperature of the application object 50 does not need to be fixed at a constant temperature during the period during which the coating liquid 15 is sprayed. The temperature of the application object 50 may vary during the period in which the application liquid 15 is sprayed. Further, in the second spraying step S <b> 14, the spraying of the coating liquid 15 does not have to be performed in a state where the temperature of the application target object 50 is higher than the temperature around the application target object 50 (room temperature, for example, 25 ° C.). For example, the application liquid 15 may be sprayed in a state where the temperature of the application object 50 is the same as or lower than the temperature around the application object 50.

  If the temperature T1 of the application target 50 in the first spraying step S12 is A1 ≦ T1 ≦ A2, and the temperature T2 of the application target 50 in the second spraying step S14 is A3 ≦ T2 ≦ A4, then A1 to A4 May satisfy the relationship of A3 ≦ A4 <A1 ≦ A2.

  As described above, according to the coating method of the present embodiment, it is possible to improve the uniformity of the coating film while forming a coating film having a sufficient thickness on the corner 51a of the step 51 or the like.

  With respect to three types of samples with different temperatures of the application object when spraying the coating liquid, the coating state of corners such as steps and the uniformity of the coating film were evaluated. Table 1 shows the results.

  Samples 1 to 3 are formed by forming a square opening having a side of 80 μm and a depth of 80 μm on one surface of an 8-inch bare Si substrate, and spraying the resist on the one surface using the spraying means of FIG. .

  The resist used was adjusted to a solid content concentration of 15% using PMER P-LA900 PM (product name: manufactured by Tokyo Ohka Kogyo Co., Ltd.) and OK73 thinner (product name: manufactured by Tokyo Ohka Kogyo Co., Ltd.).

  The amount of resist discharged from the nozzle is 0.01 cc / min, the voltage between the nozzle and the counter electrode is 2.8 kV, the gap between both ends of the counter electrode is 5 mm, and the tip of the nozzle and one surface of the coating object The distance is 8 mm, the moving pitch of the nozzle by the moving means is 0.5 mm, the moving speed by the moving means is 30 mm / sec, the number of times of application is 2, and the application area is a 100 mm square area.

  The temperature of the application target when the resist is sprayed is 50 ° C. for sample 1, 90 ° C. for sample 2, and room temperature (25 ° C.) for sample 3. In sample 3, the application target is not heated during spraying.

  As shown in Table 1, in Sample 3 in which the coating liquid was sprayed without heating the object to be coated, the uniformity of the coating film was good, but the portion where the corner of the step was not covered with the coating film I was able to. On the other hand, in Samples 1 and 2 in which the coating liquid was sprayed while heating the object to be coated, there was no break in the coating film, and the entire corner was covered with the coating film.

  In Samples 1 and 2, sample 1 having a relatively low heating temperature had better uniformity of the coating film. From this, it was found that the uniformity of the coating film and the coverage of the corners can be improved by controlling the temperature of the coating object when spraying the coating liquid within a predetermined temperature range.

DESCRIPTION OF SYMBOLS 1 ... Application | coating apparatus, 10 ... Spraying means, 11 ... Nozzle, 12 ... Counter electrode, 13 ... Voltage application means, 14 ... Moving means, 15 ... Charged particulate coating liquid, 20 ... Heating means, 30 ... Temperature Adjustment means, 50... Application object, 50a.

Claims (8)

Heating means for heating the object to be coated;
Spraying means for spraying a charged particulate coating liquid on one surface of the coating object heated by the heating means;
A coating apparatus comprising The coating apparatus according to claim 1, further comprising a temperature adjusting unit that adjusts a heating temperature of the application target by the heating unit. The spray means is
A nozzle to which the coating liquid is supplied;
A counter electrode provided facing the nozzle;
The coating apparatus according to claim 1, further comprising: a voltage applying unit configured to apply a voltage such that the coating liquid supplied to the nozzle is atomized between the nozzle and the counter electrode. The coating apparatus according to claim 3, further comprising a moving unit that relatively moves the nozzle and the application target. A heating step for heating the object to be coated;
A spraying step of spraying a charged particulate coating liquid on one surface of the coating object heated by the heating step;
A coating method comprising: The coating method according to claim 5, wherein in the heating step, the coating object is heated to a temperature of 30 ° C. or higher and 100 ° C. or lower. The spraying step includes
A coating liquid supply step for supplying the coating liquid to the nozzle;
A voltage application step of applying a voltage such that the coating liquid supplied to the nozzle is atomized between the nozzle and a counter electrode provided to face the nozzle;
The coating method according to claim 5 or 6 containing. A first temperature control step of controlling the temperature of the coating object to a first temperature by heating the coating object;
A first spraying step of spraying a charged particulate coating solution on one surface of the coating object controlled to the first temperature by the first temperature control step;
A second temperature control step of controlling the temperature of the application object sprayed with the coating liquid in the first spraying step to a second temperature lower than the first temperature;
A second spraying step of spraying the finely particulate coating liquid on one surface of the coating target controlled to the second temperature by the second temperature control step;
A coating method comprising:

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