JPH0263575A - Spin coater - Google Patents

Abstract

PURPOSE:To allow switching and combining of rotation and revolution and to easily uniformize the thickness of coated films by a revolving member which is fixed to the upper part of a main shaft, many stages of driving power transmission means which transmit the rotation of the main shaft to a jack shaft and the driven shafts fixed with coating containers and driving power intermitting mechanism which is provided on the main shaft. CONSTITUTION:The revolving member (rotary disk) 4 is fixed to the upper part of the main shaft 1 which is rotated by driving of a driving source. The driving power intermitting mechanism 15 is provided on the main shaft 1. The driving power transmission means 5 to 7 which transmit the rotation of the main shaft 1 to the jack shaft 2 and many stages of the driving power transmission means 8 to 10, 11 to 13, 11' to 13' which transmit the rotation of the jack shaft to the driven shafts 3, 3' fixed with the coating containers 14, 14' are successively provided around the main shaft. The driving power is not transmitted to the rotary disk 4 in the upper part of the main shaft by the driving power intermitting mechanism 15 and only the rotation of the driven shafts 3, 3' and the containers 14, 14' is executed right after dropping of paints onto substrates 17, 17' in this constitution. The spin coating by the combination of the revolution and rotation is executed upon lapse of the prescribed time for the purpose of uniformizing the coated film thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary coating device used for coating the surface of a flat substrate to be coated with a paint.

[Prior Art] In the industrial field related to electronic nail driving, rotary coating methods are widely used as a method for coating semiconductor substrates with viscous fluids such as photoresists. When applied to a viscous fluid exhibiting so-called Newtonian viscous flow, this rotary coating method can uniformly obtain a coating layer of any thickness over the entire surface of the substrate by setting the rotation speed and rotation time. It will be done. In particular, this uniformity is also related to the smoothness of the surface of the paint layer after drying, and furthermore, it is possible to easily prevent defects in the paint layer caused by dust, etc. by improving the equipment, compared to other painting methods. This is a unique feature.

The rotary coating method has been used and developed mainly in the electronic materials field, but recently it has also been used in the general paint field to evaluate the corrosion resistance and physical properties of the paint layer. With the increasing demand for the production of such materials, rotary coating methods have begun to be used as one method.

FIG. 1 is a side view illustrating a conventional rotary coating method and apparatus. That is, by dropping the paint (101) onto the center of the substrate to be coated and performing rotary coating with a predetermined rotation speed/time schedule, the rotary table (102)
A uniform coating layer is obtained on top.

Further, mechanically, the rotary table is rotated by a rotary shaft (103), and the rotary table is arranged so that the center of rotation and the center of the coated substrate substantially coincide with each other.

The above-mentioned rotary coating method and device are the mainstream of conventional methods and can be said to be the basics of rotary coating methods and devices, but defects in the coating layer due to dust or air bubbles or irregularities on the substrate to be coated may occur. As a solution to the non-uniform distribution of the coating layer caused by
A rotary coating method and apparatus that combines rotation and revolution have been proposed in Japanese Patent No. 1-24690.

[Problems to be Solved by the Invention] When forming the above-mentioned coating layer, conventional rotary coating methods and apparatuses do not meet the theories of ALFRED G, EMSLIE, etc.
ALFRED G, EMSLIE, FRANCIS
T, BONNERAND LESLIEG, P.E.
CK: JOURNAL OF APPLIED P
HYSIC3VOL, 29858-862 (1958)
A coating layer of uniform thickness is formed based on the theory (Reference), but the application of this theory is limited to paints that exhibit Newtonian viscous flow; in fact, for paints that exhibit non-Newtonian viscous flow, the coating layer is The thickness varies depending on the distance from the center of rotation. As an example, a paint exhibiting thixotropic viscous flow is shown in FIG.

It is possible to equalize the coating layer thickness of the paint exhibiting non-Newtonian viscous flow as described above, to prevent defects in the coating layer caused by dust and air bubbles, and to reduce the coating layer thickness due to irregularities on the substrate to be coated. Although the method and apparatus proposed in JP-A-61-246990 are considered effective for correcting non-uniformity,
Such methods and devices are intended for application to electronic materials, and cannot be applied to the production of uniform coating layers in the general coating field. Specific issues include the following:

In the method of combining revolution and rotation, it is necessary that the rotation speed of rotation is lower than the rotation speed of revolution, but the ratio of (rotation speed of rotation) ) is large, the effect of centrifugal force due to rotation is large, and when coating with a paint that exhibits non-Newtonian viscous flow as in the present invention, the coating layer formed on the substrate to be coated is The thickness distribution exhibits a distribution caused by the centrifugal force of rotation.

To avoid this, the rotation and revolution ratio should be set to 0.1.
Desirably, the ratio is approximately 0.01 or less, and it is desirable that the rotation be performed at least once during the coating time. However, in the drive mechanism of conventional equipment, a single drive source performs a combination of rotation and revolution. When trying to apply it to a painted substrate, there is a limit to miniaturizing the rotation-revolution ratio due to the geometrical positional relationship of gears, pulleys, etc. that are responsible for transmitting the drive.

In addition, as a way to minimize the rotation-revolution ratio, it may be possible to install a drive source for rotation separately from the drive source for revolution, but in this case, the centrifugal force due to the revolution will be added to the drive source for rotation, causing rotation of the revolution. It is foreseen that there will be a limit to the number, and that it will also cause a failure of the rotational drive source. Furthermore, if separate drive sources are installed for rotation and revolution, the synchronization between revolution and revolution will be impaired, which is a problem that cannot be ignored.

The second problem is that the paint dropped onto the substrate to be coated spreads on the substrate. In the method that combines revolution and rotation, the driving force that spreads the paint on the substrate to be coated is the centrifugal force due to the revolution, and its center is not on the substrate to be coated. Therefore, the dropped coating cannot be spread over the entire surface of the substrate to be coated, resulting in uncoated areas. In order to avoid this, it is necessary to drip excess paint and supply the paint to the entire surface of the substrate to be coated before the rotation starts. However, this kind of response is unsuitable.
This is not a preferable method as it significantly reduces the yield. However, in order to efficiently spread the paint on the substrate to be coated, even in a method that combines rotation and revolution, centrifugal force must be applied during the process of spreading the coating on the substrate after the diagonal dripping. It is desirable that the center be located at the center of the substrate to be coated. This means that even in a method that combines rotation and revolution, it is necessary to provide a drive system in which the centrifugal force of the rotation acts on the coating t during the spreading process of the coating t1 located in the initial coating process. It is characterized by having.

This invention was made in view of the above circumstances, and it is possible to easily obtain a coating layer with a uniform thickness over general paints in general, and especially in coating F which exhibits non-Newtonian viscous flow. The purpose of the present invention is to provide a rotary coating device that can be used.

[Means for Solving the Problem] Corresponding to this purpose, the rotary coating device of the present invention has a main shaft (1) rotated by a power source, and a revolving member (4) fixed to the main shaft (1). ), power transmission means (5), (6), (7) for transmitting the rotation of the main shaft (1), and a subshaft () rotated by the power transmission means (5), (6), (7). 2
), and a power transmission means (8) for transmitting the rotation of the subshaft (2).
), (9), (10) and the power transmission means (8), (9
), (10), are rotatably arranged around the main shaft (1), and are connected to the power transmission means (10); power transmission means (12), (12'), (13), (13') for transmitting the rotation of the means (11), (11'); ), (13
'), and the power transmission means (11), (11
Driven shafts (3), (3') arranged symmetrically with respect to the revolving member (4) and rotatably fixed to the revolving member (4)
and the coating containers (14), (14') fixed to the driven shafts (3), (3'''), and the power transmission means (5), (6), (7) of the main shaft (1). A power intermittent mechanism (15) is provided between the power transmitting means (8), (9), and (10).
) is a rotary coating device.

In the case of a coating layer obtained by applying a coating material exhibiting non-Newtonian viscous flow to a substrate to be coated by the above method, and using the conventional rotary coating method using rotation as the only acting force, the thickness distribution of the obtained coating layer is changed. A comparison is shown in Figure 3. From this result, it is clear that by using the rotary coating apparatus of the present invention, a uniform coating layer of general paints including paints exhibiting non-Newtonian viscous flow can be obtained.

[Example] An example of the present invention will be described using a longitudinal cross-sectional view shown in FIG.

In Fig. 4, 1 is the main shaft, 2 is the sub-shaft, 3.3 is the driven shaft, 4 is the revolving member, and 5.7.8.13.13' is the timing pulley fixed to each shaft. ' is a timing pulley arranged rotatably around the main shaft and connected to each other; 6.9.12.12' is a timing belt; 14.1/1' is a coating container; 15 is a power intermittent mechanism; 16.16' 17, 17' is the coating container lid, 18, 19, 20, 21, and 21' are the bearings, and 22 is a part of the national body.

In the rotary coating apparatus having such a configuration, the timing pulley (5) is fixed to the main shaft (1), the timing pulleys (7) and (8) are connected and fixed to both ends of the subshaft (2), and the timing pulley (5) is fixed to the main shaft (1). 2) passes through the sleeve and is held in the bearing bearing. Timing pulley (10
), (11), (11”) are connected to each other, and the main shaft (1
) is held through a bearing.

The timing pulleys (13) and (13') are connected to the driven shaft (
3), fixed to the lower end of (3'). Driven shaft (3)
The driven shaft (3') and the driven shaft (3') are held by a rotating member (4) fixed to the upper end of the main shaft (1) at symmetrical positions with respect to the main shaft (1) through bearings, respectively.

The timing belt responsible for power transmission is located between timing pulley (5) and timing pulley (7), between timing pulley (8) and timing pulley (10), and between timing pulley (11) and timing pulley (13).
between the timing pulley (11') and the timing pulley (13').

According to the rotary coating device having the drive mechanism configured as described above,
The main shaft (1) is rotated by the drive of a power source such as a motor,
The rotation is transmitted from the timing pulley (5) fixed to the main shaft (1) to the timing belt (6) to the retiming pulley (7), and then to the timing pulley (7).
The rotation is transmitted to the timing pulley (10) by the timing belt (9) via the timing belt (9). The rotation of the timing pulley (10) passes through the timing pulleys (ll) and (11') connected to it, and then the timing belt (
12) and (12'') to the timing pulleys (13) and (13'), respectively.

The rotation of the timing pulleys (13) and (13') is transmitted to the driven shaft (3) = (3'), and further, the driven shaft (3) is transmitted to the driven shaft (3) = (3').
), a paint container (14) fixed to the top of (3'),
(14”) is rotated on its axis.Then, the coating container (14”) is rotated on its axis.
4) The necessary amount of paint is dropped onto the substrate to be painted mounted in (14'), and the rotary painting is performed by combining revolution and rotation based on the above-mentioned drive mechanism.

In the series of rotational drive transmission described above, the number of teeth on the timing pulley (5) is a, the number of teeth on the timing pulley (7) is b, the number of teeth on the timing pulley (8) is C, and the number of teeth on the timing pulley (10) is If the number of firs is d, the number of teeth of timing pulleys (11) and (11''') is e, and the number of teeth of timing pulleys (13) and (13') is [,
Rotation ratio (R) (rotation speed [driven shaft (3), (3
= ) rotation speed]/revolution rotation speed [rotation speed of main shaft (1)]) is given by the following formula.

R= (ac/bd-1)d/f However, when Rho, the direction of rotation is the same as the direction of revolution, when Rho, the direction of rotation is opposite to the direction of revolution, and R=O. When, it only revolves.

Therefore, the R value can be set to an arbitrary value by setting the five variables a - f to determine the number of teeth of the timing pulley in consideration of geometrical conditions such as the diameter of the shaft and the distance between the shafts. As a result, the above-mentioned rotation-revolution ratio is 0.1 or less,
Moreover, it is possible to satisfy the requirement that rotation is performed at least once during the coating time, and it is possible to form a uniform and defect-free coating layer in a coating material exhibiting non-Newtonian viscous flow.

The rotary coating device of this invention uses a single power source to
It is characterized by the ability to arbitrarily select the rotation-revolution ratio. 1. It is impossible to achieve the above-mentioned rotational movement with a single power source using conventional technology. Furthermore,
The unique feature of having a single power source is that it has excellent synchronization between revolution and rotation.

In the rotary coating method of the present invention, a power intermittent mechanism (15) shown in FIG. 4 is installed in order to efficiently spread the paint dropped onto the substrate to be coated over the entire surface of the substrate to be coated. The following painting schedule is implemented by the operation of this power intermittent mechanism (15).

That is, immediately after the paint is dripped onto the substrate to be painted, the driving force of the power source is not transmitted to the rotating disk (4) attached to the upper part of the main shaft due to the power intermittent mechanism (15), and the driving force is not transmitted to the driven shaft (2) and the driven shaft (2). It is used to rotate only (2'). Therefore, the rotating container holding the substrate to be coated (14) - (14
' ) performs only rotation. Immediately after the coating is dropped, the rotation process is set within several seconds, and thereafter, rotational coating is performed by combining revolution and rotation in order to make the coating thickness uniform.

During the rotation process in the above painting schedule, the paint dropped at the center of the substrate to be painted spreads all over the surrounding area because the center of rotation is also at the center of the substrate to be painted, and even if a relatively small amount of paint is dropped, no paint will be applied. can be prevented from occurring.

In addition, when using a method that combines rotation and revolution, when painting two or more substrates at the same time, there is a risk that the paint splashes generated during coating will fall onto the painted surface of the substrates. This problem can be avoided by mounting the substrate to be coated in a rotating container with a lid, as in the embodiment of the present invention.

[Brief explanation of the drawing]

Figure 1 is a side view showing the basic configuration of a conventional rotary coating device, and Figure 2 is an example of the coating thickness distribution of coating t[, which exhibits non-Newtonian viscous flow, obtained by the conventional rotary coating method. Figure 3 is a graph showing the coating film thickness distribution obtained by applying the rotary coating device of the present invention for coating F) showing non-Newtonian viscous flow, compared with that obtained using a conventional rotary coating device. The graph and FIG. 4 are longitudinal sections of a rotary coating apparatus according to an embodiment of the present invention. 1o1: Paint 102: Rotating table 103: Rotating shaft
104: Substrate to be painted 105: Motor 106: Thickness of coating layer 107: Distance 108: Center of rotation 1
09: Thickness distribution of coating layer by conventional rotary coating equipment
110: When the thickness distribution of the coating layer by the rotary coating device of this invention, Applicant Toyo Ink Mfg. Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] A main shaft (1) rotated by a power source, a revolving member (4) fixed to the main shaft (1), and power transmission means (5), (6) for transmitting the rotation of the main shaft (1), (7) and a subshaft (
2), and a power transmission means (
8), (9), (10) and the power transmission means (8), (
9) and (10), power transmission means (11) and (11') rotatably arranged around the main shaft (1) and connected to the power transmission means (10); power transmission means (12), (12'), (13), (13') for transmitting the rotation of the transmission means (11), (11'); (13), (13
'), and the power transmission means (11), (11
Driven shafts (3), (3') arranged symmetrically with respect to the revolving member (4) and rotatably fixed to the above-mentioned revolving member (4).
and the coating container (1) fixed to the driven shafts (3), (3').
4), (14'), the power transmission means (5), (6), (7) of the main shaft (1), and the power transmission means (8),
A rotary coating device characterized in that a power intermittent mechanism (15) is provided between (9) and (10).