JP2007275717A - Spin coat apparatus and spin coat method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spin coat apparatus capable of reducing nonuniformity of a film thickness generated in a concentric circle direction to a rotation shaft of the spin coat apparatus, and a spin coat method. <P>SOLUTION: The spin coat apparatus is provided with a table 2 placed with an object 9 to be coated and rotated in the state that it is integrated with the object 9 to be coated, a coating liquid feeding means 4 for feeding a coating liquid to the object 9 to be coated, and a rotation means 5 for rotating the table 2. The coating liquid feeding means 4 has a nozzle 61 provided so as to be opposed to at least the whole surface of the object 9 to be coated and feeding the coating liquid in a feeding amount distribution of a concentric circle-like shape making the rotation shaft 2a as a center that a feeding amount per unit area is reduced at an area near the rotation shaft 2a of the table 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a spin coating apparatus and a spin coating method, and in particular, a spin coating apparatus that can reduce film thickness unevenness of a coating film that occurs concentrically with a rotation axis of the spin coating apparatus, and the spin coating apparatus. And spin coating.

Conventionally, as one method for forming a thin film, a spin coating method using a spin coating apparatus has been used. In the spin coating method, a coating solution is formed by supplying a coating solution to a surface to be coated such as a substrate and applying the coating solution to the surface to be coated with a centrifugal force generated by rotating the surface to be coated. In the spin coating method, generally, the film thickness of the coating film is controlled by the number of rotations, the rotation holding time, the concentration and viscosity of the coating solution, and the like.
Such spin coating methods include, for example, various thin films constituting organic EL elements, photoresist films used in semiconductor manufacturing processes, interlayer insulating films such as SOG (spin on glass), and overcoat films in liquid crystal device manufacturing processes. (Flattening film), alignment films, and further widely used for forming protective films and the like in the manufacturing process of optical disks and the like.

However, in the conventional spin coating method, since the coating liquid flows from the inside to the outside due to the centrifugal force generated by rotating the substrate, the film thickness of the coating film near the outer edge is larger than the film thickness of the inner coating film. There is also a disadvantage that the film thickness of the obtained coating film becomes non-uniform.
As a coating method that can form a uniform coating film, a method is proposed in which coating is performed so that the film thickness in the direction perpendicular to the coating direction of the coating film is maximized at the center (for example, Patent Documents). 1).
Japanese Patent Laid-Open No. 9-276781

  However, in the method described in Patent Document 1, the film thickness in the direction perpendicular to the coating direction of the coating film is maximized at the central portion by relatively moving on the coating substrate while supplying the coating liquid from the slit. Since the coating on the coated substrate is performed so as to become, there are the following problems.

  That is, in the method described in Patent Document 1, it takes time to move the slit relative to the substrate to be coated in order to apply the coating liquid to the entire surface of the substrate to be coated. By the time, the coating liquid supplied in the initial stage where the movement of the slit is started flows. For this reason, before the start of spin coating, the thickness of the coating film becomes substantially uniform, and in some cases, film thickness unevenness due to the centrifugal force of spin coating cannot be reduced sufficiently. In particular, when the viscosity of the coating liquid is low, the coating liquid tends to flow, and therefore, the film thickness of the coating film becomes almost uniform before the spin coating is started.

  In addition, before the movement of the slit is completed, the solvent in the coating liquid supplied at the initial stage where the movement of the slit started is volatilized, and the concentration of the coating liquid applied on the substrate to be coated is not uniform. There was a case. For this reason, the coating film formation speed at the time of spin coating becomes non-uniform, and the film thickness unevenness due to the centrifugal force of spin coating may not be sufficiently reduced.

  Furthermore, in the method described in Patent Document 1, coating is performed such that the film thickness in the direction perpendicular to the coating direction of the coating film is maximized in the central portion, so that the maximum portion is formed in a band shape, In some cases, film thickness unevenness occurs in a direction perpendicular to the coating direction of the film. In particular, when the viscosity of the coating solution is high, the coating solution is difficult to flow, and thus the film thickness unevenness in the direction perpendicular to the coating direction of the coating film becomes remarkable.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a spin coater that can reduce film thickness unevenness regardless of the viscosity of a coating solution.
It is another object of the present invention to provide a spin coating method using the spin coating apparatus.

  In order to achieve the above-mentioned object, the present inventor has conducted extensive research, and when the coating liquid is uniformly supplied to the entire surface to be coated and spin-coated, the film thickness distribution of the obtained coating film is determined by the spin-coating apparatus. It was confirmed that the film thickness was thinner in a region concentric with the rotation axis of the table and closer to the rotation axis of the table. In order to effectively reduce the film thickness unevenness, the present inventor applied the coating so as to offset the concentric film thickness unevenness that occurs when the coating liquid is supplied uniformly over the entire surface to be coated. The coating liquid is supplied to the surface, and it is found that it is only necessary to reduce the film thickness unevenness of the coating film that occurs concentrically with the rotation axis of the spin coater, and the film thickness unevenness is reduced regardless of the viscosity of the coating liquid. The present inventors have found a spin coating apparatus and a spin coating method according to the present invention.

  That is, the spin coater of the present invention includes a table on which an object to be coated is placed and rotated in an integrated state with the object to be coated, and a coating liquid supply unit that supplies the coating liquid to the object to be coated. And a rotating means for rotating the table, wherein the coating liquid supply means is provided to face at least the entire surface of the object to be coated, and has a nozzle for supplying the coating liquid with a supply amount distribution having a bias. Features.

  In such a spin coater, the coating liquid supply means is provided so as to face at least the entire surface of the object to be coated, and has a nozzle for supplying the coating liquid with a supply amount distribution having a bias. The coating liquid can be supplied to the surface to be coated with a distribution of supply amount that cancels out the concentric film thickness unevenness that occurs when the coating liquid is uniformly supplied and the table is rotated to form a coating film. Therefore, it is possible to reduce film thickness unevenness that occurs concentrically with the rotation axis of the spin coater.

  In the spin coater of the present invention, since the nozzle is provided so as to face at least the entire surface of the object to be coated, the entire surface of the object to be coated is moved without moving the slit as in the conventional coating method. A coating solution can be supplied. Therefore, the time between the start and end of supplying the coating liquid to the coating object can be very short, and even when the viscosity of the coating liquid is low, the supply of the coating liquid to the coating object is started. Then, it is possible to effectively prevent the coating liquid from flowing between the end and the end. In addition, it is possible to effectively prevent the solvent in the coating liquid from volatilizing during the period from the start to the end of the supply of the coating liquid to the object to be coated.

In the spin coater of the present invention, the supply amount distribution may be concentric with the rotation axis of the table having a deviation in the radial direction of the table as a center.
In such a spin coater, the coating liquid supply means supplies the coating liquid in a concentric supply amount distribution centering on the rotation axis of the table having a deviation in the radial direction of the table. The coating liquid is supplied to the surface to be coated with a distribution distribution that effectively cancels the concentric film thickness unevenness that occurs when a coating film is formed by supplying the coating liquid uniformly over the entire surface and rotating the table. can do. Therefore, it is possible to effectively reduce the film thickness unevenness that occurs in the direction concentric with the rotation axis of the spin coater.
Further, since such a spin coater supplies the coating liquid in a concentric supply amount distribution centered on the rotation axis of the nozzle, even when the viscosity of the coating liquid is high, Unlike the coating method, the film thickness unevenness in the direction perpendicular to the coating direction of the coating film does not become significant.

In the spin coater of the present invention, the supply amount distribution may be characterized in that the supply amount per unit area is reduced in a region closer to the rotation axis.
In such a spin coater, the coating liquid supply means supplies the coating liquid with a supply amount distribution in which the supply amount per unit area is reduced in a region closer to the rotation axis. The coating liquid can be supplied to the surface to be coated with a supply amount distribution that effectively cancels the concentric film thickness unevenness that occurs when the coating is formed by supplying the liquid and rotating the table. Therefore, it is possible to effectively reduce the film thickness unevenness that occurs in the direction concentric with the rotation axis of the spin coater.

Further, in the spin coater of the present invention, a plurality of supply holes are provided on the facing surface of the nozzle facing the object to be coated, and the density of the supply holes on the facing surface is uniform. Can do.
By using such a spin coater, a spin coater equipped with a nozzle for supplying a coating liquid with a predetermined supply amount distribution can be easily realized by controlling the supply amount of the coating liquid for each supply hole.

In the spin coater of the present invention, a plurality of supply holes are provided in a facing surface of the nozzle facing the object to be coated, and the density of the supply holes in the facing surface corresponds to the supply amount distribution. Can be.
In such a spin coater, since the density of the supply holes on the facing surface corresponds to the supply amount distribution, the supply amount of the coating liquid is not changed for each supply hole. A spin coater including a nozzle for supplying a coating solution can be easily realized. Therefore, compared with the case where the supply amount of the coating liquid is controlled for each supply hole, the supply amount of the coating liquid can be easily controlled.

In the spin coater of the present invention, the supply amount of the coating liquid can be controlled for each supply hole.
By setting it as such a spin coater, the area | region and supply amount distribution which supply a coating liquid can be easily changed according to the shape and magnitude | size of a to-be-coated object, the viscosity of a coating liquid, etc.

  In order to achieve the above object, the spin coating method of the present invention is a method of spin coating using any one of the above spin coating apparatuses, wherein the coating object is the same as the coating object. A placing step of placing the substrate on the table so as to be rotated in an integrated state; a coating solution supplying step of feeding the coating solution from the nozzle to the object to be coated; and a rotating step of rotating the table. And the rotation process is started simultaneously with the end of the coating liquid supply process.

  In such a spin coating method, since the rotation process is started at the same time as the application liquid supply process is completed, the period from when the application liquid is supplied with the above supply amount distribution in the application liquid supply process until the rotation process is started. In addition, the coating liquid does not flow and the solvent in the coating liquid does not volatilize. Therefore, it is possible to effectively reduce the film thickness unevenness that occurs concentrically with the rotation axis due to the supply of the coating liquid in the supply amount distribution.

  In order to achieve the above object, the spin coating method of the present invention is a method of spin coating using any one of the above spin coating apparatuses, wherein the coating object is the same as the coating object. A placing step of placing the substrate on the table so as to be rotated in an integrated state; a coating solution supplying step of feeding the coating solution from the nozzle to the object to be coated; and a rotating step of rotating the table. The coating liquid supply step and the rotation step are performed simultaneously.

  In such a spin coating method, since the coating liquid supply process and the rotation process are performed simultaneously, the supply liquid is supplied with the above supply amount distribution in the coating liquid supply process until the rotation process is started. The coating solution does not flow and the solvent in the coating solution does not volatilize. Therefore, it is possible to effectively reduce the film thickness unevenness that occurs concentrically with the rotation axis due to the supply of the coating liquid in the supply amount distribution.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing used in the following description, the scale is different for each layer and each member so that each layer and each member can be recognized on the drawing.
(Spin coating equipment)
FIG. 1 is a diagram schematically showing an example of the spin coater of the present invention.
A spin coater 1 shown in FIG. 1 includes a table 2, a chamber 3, a coating liquid supply unit 4, and a rotation unit 5.

  As shown in FIG. 1, the table 2 is installed in a sealable chamber 3 on which an object 9 such as a substrate is placed. The table 2 is configured such that the workpiece 9 can be detachably fixed on the table 2 by adsorbing the placed workpiece 9 with a suction means or the like. Further, the table 2 is rotated by the rotating means 5 in a state where the object 9 is fixed on the table 2 and integrated with the object 9. Further, the table 2 is rotated at a predetermined rotation speed and rotation time by causing a rotation control device (not shown) to control the rotation speed and rotation time of the rotation means 5.

  The coating liquid supply means 4 supplies the coating liquid to the article 9 to be coated. As shown in FIG. 1, the coating liquid supply means 4 is provided in the chamber 3 and is provided outside the chamber 3 and a nozzle 61 for discharging the coating liquid. The coating liquid tank 63a for storing the coating liquid, the coating liquid supply pipe 62 provided through the chamber 3 for supplying the coating liquid from the coating liquid tank 63a to the nozzle 61, and the coating liquid in the coating liquid tank 63a are provided. And a pump 64a that pumps the nozzle 61 at a predetermined pressure. In the coating liquid supply means 4 shown in FIG. 1, the coating liquid supply pipe 62 includes individual supply pipes 62a that supply the coating liquid individually for each supply hole 61b to be described later, and each individual supply pipe 62a includes a pump. 64a and a coating liquid tank 63a are provided, and the supply amount of the coating liquid can be controlled for each supply hole 61b. In FIG. 1, only one of the plurality of pumps 64a and the coating liquid tank 63a is shown to make the drawing easy to see.

  As shown in FIG. 1, the nozzle 61 is provided to face the entire surface of the workpiece 9. As shown in FIG. 2, when the coating liquid is uniformly supplied to the object 9 to be coated, a film thickness distribution is generated in the concentric direction due to the difference in centrifugal force. Therefore, the supply amount distribution of the coating liquid supplied from the nozzle 61 is a supply amount having a deviation in the radial direction of the table 2 in which the supply amount per unit area is reduced in the region (center region) closer to the rotation shaft 2a of the table 2. Distribution.

FIG. 3 is a diagram showing nozzles provided in the spin coater 1 shown in FIG. 1 and is a plan view seen from the side facing the object 9 to be coated.
The planar shape of the nozzle 61 shown in FIG. 3 is a circle having the same diameter as the workpiece 9. In addition, although the diameter of the nozzle 61 can be made the same as the to-be-coated object 9, it should just be the diameter more than the diameter of the to-be-coated object 9, and does not need to be the same. In addition, a plurality of supply holes 61b are provided in the facing surface 61a of the nozzle 61 facing the object 9 to be coated. The density of the supply holes 61b in the facing surface 61a is uniform. In the nozzle 61 shown in FIG. 3, the supply amount of the coating liquid can be controlled for each supply hole 61a by the pump 64a and the coating liquid tank 63a provided for each supply hole 61b. The shape and size of the supply hole 61b are not particularly limited, but may be a circle having a diameter of 1 mm to 2 mm, for example.

In order to perform spin coating using the spin coater 1 shown in FIG. 1, first, the object 9 is placed on the table 2 so as to be rotated in an integrated state with the object 9 ( Placement process). Next, with the inside of the chamber 3 sealed, the pump 64a corresponding to each supply hole 61a causes the coating liquid in the coating liquid tank 63a corresponding to each supply hole 61a to go to each supply hole 61a of the nozzle 61. The coating liquid is supplied from the nozzle 61 to the object 9 via the coating liquid supply pipe 62 (coating liquid supply process), and the rotation of the table 2 by the rotating means 5 is started at the same time as the supply of the coating liquid is completed. (Rotation process). Thereafter, the spin coating is completed by terminating the rotation of the table 2.
In the present embodiment, the time required for the coating liquid supply step is 0.5 seconds or less.

  In the spin coater 1 of the present embodiment, the coating liquid supply means 4 is provided so as to face at least the entire surface of the object 9 and the supply amount per unit area is reduced in the region closer to the rotating shaft 2 a of the table 2. Since it has the nozzle 61 which supplies a coating liquid with the concentric supply amount distribution centering on the rotating shaft 2a, the coating liquid was supplied uniformly to the whole surface of the to-be-coated object 9, and the table was rotated, and the coating film was formed. The coating liquid can be supplied to the surface to be coated 9 with a supply amount distribution that cancels out the concentric film thickness unevenness that sometimes occurs. Therefore, the film thickness unevenness generated in the direction concentric with the rotating shaft 2a of the spin coater 1 can be reduced.

In the spin coater of the above-described embodiment, the example provided with the nozzle 61 shown in FIG. 3 has been described as an example. However, the nozzle 61 is not limited to the one shown in FIG. The nozzle shown in FIGS. 4 to 6 may be provided.
4-6 is a figure which shows the other example of the nozzle with which the spin coater of this invention is provided, Comprising: It is the top view seen from the side facing a to-be-coated object.

  The planar shape of the nozzle 65 shown in FIG. 4 is a square having sides having the same length as the diameter of the workpiece 9. In addition, although the length of the side of the nozzle 65 can be made the same as the to-be-coated object 9, it should just be the length more than the diameter of the to-be-coated object 9, and does not need to be the same. In addition, a plurality of supply holes 65 b are provided on the facing surface 65 a of the nozzle 65 facing the workpiece 9. The density of the supply holes 65b in the facing surface 65a is uniform. Also in the nozzle 65 shown in FIG. 4, similarly to the nozzle 61 shown in FIG. 3, the supply amount of the coating liquid can be controlled for each supply hole 65 a by a supply amount control device (not shown).

  The planar shape of the nozzle 66 shown in FIG. 5 is a circle having the same diameter as that of the workpiece 9, as with the nozzle 61 shown in FIG. 3. In addition, when the diameter of the nozzle 66 is the same as that of the article 9 to be coated, it is preferable that the coating liquid not applied onto the article 9 is reduced. However, the diameter of the nozzle 66 is equal to or larger than the diameter of the article 9 to be coated. It does not have to be the same. Further, a plurality of supply holes 66b are provided on the facing surface 66a of the nozzle 66 facing the object 9 to be coated, like the nozzle 61 shown in FIG. However, unlike the nozzle 61 shown in FIG. 3, the density of the supply holes 66b in the facing surface 66a is not uniform. In the nozzle 66 shown in FIG. 5, the supply holes 66b are arranged in three rings having different diameters except for the center, and the density of the supply holes 66b on the facing surface 66a corresponds to the supply amount distribution. Yes. Therefore, in the nozzle 66 shown in FIG. 5, for example, the spin coater 10 shown in FIG. 7 is used, and the supply amount of all the supply holes 66b is made the same without changing the supply amount of the coating liquid for each supply hole 66b. The distribution area of the concentric circle centered on the rotation shaft 2a, the supply amount per unit area of which is close to the rotation axis 2a of the table 2 compared to the area far from the rotation axis 2a, The coating liquid can be supplied in a supply amount distribution having a bias corresponding to the density of the holes 66b.

  FIG. 7 is a view schematically showing another example of the spin coater of the present invention, which is provided with a coating liquid supply means for supplying the same amount to all the supply holes. Unlike the spin coating apparatus 1 shown in FIG. 1, the coating liquid supply means 4 constituting the spin coating apparatus 10 shown in FIG. 7 includes only one coating liquid tank 63 and one pump 64. In the spin coater 10 shown in FIG. 7, the pump 64 feeds the coating liquid in the coating liquid tank 63 to all the supply holes 66 a with a uniform pressure, and the coating liquid is supplied from the nozzle 66 through the coating liquid supply pipe 62. A coating solution is supplied to the coating 9.

  Further, the planar shape of the nozzle 67 shown in FIG. 6 is a circle having the same diameter as that of the article 9 to be coated, like the nozzle 61 shown in FIG. In addition, when the diameter of the nozzle 67 is the same as that of the article 9 to be coated, it is preferable that the amount of the coating liquid not applied on the article 9 is reduced. However, the diameter of the nozzle 67 is larger than the diameter of the article 9 to be coated. It does not have to be the same. In addition, a plurality of supply holes 67b are provided on the facing surface 67a of the nozzle 67 facing the workpiece 9 in the same manner as the nozzle 61 shown in FIG. However, unlike the nozzle 61 shown in FIG. 3, the density of the supply holes 67b in the facing surface 67a is not uniform. In the nozzle 67 shown in FIG. 6, the supply holes 67b are arranged in eight spirals extending outward from the center, and the density of the supply holes 67b on the facing surface 67a corresponds to the supply amount distribution. Yes. Therefore, in the nozzle 67 shown in FIG. 6, for example, the spin coater 10 shown in FIG. 7 is used, and the supply amount of all the supply holes 67b is made the same without changing the supply amount of the coating liquid for each supply hole 67b. Thus, the coating liquid can be supplied in a supply amount distribution having a bias corresponding to the density of the supply holes 67b.

  Further, as described above, the supply amount distribution can be adjusted by a method for controlling the supply amount of the coating liquid for each supply hole or a method for making the density of the supply holes correspond to the supply amount distribution. The size of the supply hole may be adjusted as appropriate.

  In the spin coating method of the embodiment described above, the rotation of the table 2 by the rotating means 5 is started simultaneously with the end of the supply of the coating liquid. However, the coating liquid supply process and the rotation process may be performed simultaneously. In either case, the coating liquid flows or the solvent in the coating liquid volatilizes after the coating liquid is supplied with the above supply amount distribution in the coating liquid supply process until the rotation process starts. There is nothing to do. Therefore, it is possible to effectively reduce the film thickness unevenness that occurs concentrically with the rotation shaft 2a due to the supply of the coating liquid with the above supply amount distribution.

FIG. 1 is a diagram schematically showing an example of the spin coater of the present invention. FIG. 2 is a graph showing the relationship between the distance from the center and the film thickness. FIG. 3 is a view showing nozzles provided in the spin coater shown in FIG. 1 and is a plan view seen from the side facing the object to be coated. FIG. 4 is a view showing another example of the nozzle provided in the spin coater of the present invention, and is a plan view seen from the side facing the object to be coated. FIG. 5 is a view showing another example of the nozzle provided in the spin coater of the present invention, and is a plan view seen from the side facing the object to be coated. FIG. 6 is a view showing another example of the nozzle provided in the spin coater of the present invention, and is a plan view seen from the side facing the object to be coated. FIG. 7 is a view schematically showing another example of the spin coater of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 10 Spin coater, 2 tables, 3 chambers, 4 coating liquid supply means, 5 rotation means, 9 to-be-coated object, 61, 65, 66, 67 nozzle, 62 coating liquid supply pipe, 63, 63a Coating liquid tank.

Claims (8)

A table on which an object to be coated is placed and rotated in an integrated state with the object to be coated;
A coating liquid supply means for supplying a coating liquid to the object to be coated;
Rotation means for rotating the table,
The spin coating apparatus, wherein the coating liquid supply means includes a nozzle that is provided to face at least the entire surface of the object to be coated and supplies the coating liquid with a supply amount distribution having a bias.   2. The spin coater according to claim 1, wherein the supply amount distribution is concentric with a rotation axis of the table having a bias in a radial direction of the table. 3.   3. The spin coater according to claim 1, wherein the supply amount distribution has a smaller supply amount per unit area in a region closer to the rotation axis. 4. A plurality of supply holes are provided on a surface of the nozzle facing the object to be coated,
The spin coater according to any one of claims 1 to 3, wherein the density of the supply holes on the facing surface is uniform. A plurality of supply holes are provided on a surface of the nozzle facing the object to be coated,
The spin coater according to any one of claims 1 to 3, wherein a density of the supply holes on the facing surface corresponds to the supply amount distribution.   The spin coating apparatus according to claim 1, wherein the supply amount of the coating liquid can be controlled for each supply hole. A method of spin coating using the spin coating apparatus according to any one of claims 1 to 6,
A placing step of placing the object to be coated on the table so as to be rotated in an integrated state with the object to be coated;
A coating liquid supply step of supplying the coating liquid from the nozzle to the object to be coated;
A rotation step of rotating the table,
A spin coating method, wherein the rotation step is started simultaneously with the end of the coating liquid supply step. A method of spin coating using the spin coating apparatus according to any one of claims 1 to 6,
A placing step of placing the object to be coated on the table so as to be rotated in an integrated state with the object to be coated;
A coating liquid supply step of supplying the coating liquid from the nozzle to the object to be coated;
A rotation step of rotating the table,
A spin coating method comprising performing the coating liquid supplying step and the rotating step simultaneously.

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