JP2000301043A - Rotary coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To coat with the small quantity of a coating liquid without forming a primary coating film into a round shape at the central part of a rotating base plate or an non-uniform state, which exerts large influence on a secondary coating film, at the time of forming the secondary coating film by the centrifugal force generated by high speed rotation after forming the primary coating film using a coating head. SOLUTION: This coating device is equipped with a rotary table 4 holding a base plate 3 by suction to face a flat coating surface upward and rotating and an elevating device elevating and lowering relatively to the coating head 5, the coating head 5 is divided into a 1st coating head for coating a circular coating surface to have an opening part as the radius and a 2nd coating head for coating a 1st ring-shaped coating surface (b) to have a circular coating surface (a) as the inscribed circle and the same coating surface area as that of the circular coating surface (a) and the coating is performed to uniformize the thickness of the primary coating film by the cooperation of the rotation of the base plate by the rotary table 4 with the quantitative discharge of the coating liquid by the 1st coating head and the 2nd coating head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary coating apparatus, and more particularly to a coating apparatus which discharges a coating liquid onto a surface of a member to be coated such as a flat sheet member such as a glass substrate or a metal plate to form a coating film. Occasionally, the present invention relates to a rotary coating apparatus capable of realizing a liquid-saving coating for forming a coating film having a uniform thickness using a smaller coating liquid on a flat substrate such as a semiconductor substrate, a liquid crystal glass substrate, a printed substrate, and a plasma display. .

[0002]

2. Description of the Related Art A rotary coating apparatus using a spin coating method is known as an apparatus for uniformly applying a resist solution or the like to a substrate in a semiconductor manufacturing process or a liquid crystal display device manufacturing process.

[0003] According to this rotary coating apparatus, a large amount of coating liquid is dropped at the center while rotating at a low speed, and then rotated at a high speed while holding the substrate with the coated surface up and suctioning and holding the back side. By the effect of centrifugal force, it spreads evenly,
In addition, excess coating solution was shaken off. For this reason, a coating liquid that is several tens to nearly one hundred times the amount of the coating film required for the effective coating surface of one substrate is consumed. Since the coating liquid is often extremely expensive, waste of the liquid has been a serious problem.

[0004] In order to suppress the consumption of the coating liquid, there has been proposed a coating method using a coating head capable of coating with a predetermined width. That is, as disclosed in JP-A-4-332116 and JP-A-7-28715,
A primary coating film is formed on a substrate having a flat coating surface by quantitatively discharging a coating liquid using a coating head having a linear opening having a predetermined width, and the primary coating film is formed by centrifugal force accompanying high-speed rotation. A technique for forming a desired thin film by forming a secondary coating film by uniformly diffusing the film is known.

[0005] Further, in the case of a circular substrate, a method is known in which a coating head is disposed at the center of rotation of the substrate, and the substrate is rotated to apply the coating over substantially the entire area of the effective coating surface.

[0006] However, the primary coating film obtained by using the coating head extending in the radial direction is thick at the center and becomes thinner toward the outer periphery of the substrate due to the difference in the peripheral speed. The quality of the coating film is determined by how the coating liquid is applied over the entire effective surface before high-speed rotation. That is, since the primary coating is performed so as not to cause the fogging phenomenon in the outer peripheral portion, the mountain-shaped coating in which the central portion becomes high cannot be avoided, and the waste of the liquid still cannot be eliminated.

[0007] In order to improve such a point that the central portion has a mountain shape, there are Japanese Patent Application Laid-Open No. Sho 59-112873 and Japanese Utility Model Registration No. 300824. According to Japanese Patent Application Laid-Open No. Sho 59-12878, a large number of fine pore nozzles are arranged in a straight line so that the fine pore diameter becomes larger toward the outer circumference of rotation or the length of fine pore becomes shorter toward the outer circumference. Thus, the resistance in the pipe is reduced. In addition, utility model registration 3
The technique of No. 004824 expands the opening width of the coating head from the center of rotation to the outer periphery.

However, the fluid to be pressure-fed from the communicating flow paths tends to flow through the flow path having a low resistance. In some cases, it may not be possible to discharge the ink at the center. There is a limit to a method of controlling the discharge amount by providing a certain resistance difference in the opening width, and it is difficult to obtain a uniform primary coating thin film as expected.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 10-284381, after forming a primary coating film coated in a stripe or grid pattern using a coating head, the primary coating film is formed by centrifugal force accompanying high-speed rotation. An apparatus that uniformly diffuses to form a secondary coating film has also been proposed.

[0010]

On the other hand, according to Utility Model Registration No. 300824, the direction of the opening of the coating head is arranged in the radial direction of the rotating substrate while rotating the substrate, and the speed is controlled in the outer peripheral direction. While moving. However, in this method, the longer the length of the opening of the coating head is, the more it is necessary to devise the discharge amount between the rotation center and the outer periphery. Further, if the length is shortened, a considerable time is required until the application is completed. Therefore, there is a problem that thick coating due to the progress of drying is inevitable, so that the solution efficiency still needs to be improved. Furthermore, the primary coating film proposed in JP-A-10-284381 is
Since the coating is not applied along the high-speed rotation direction when forming the secondary coating film, it is difficult to achieve uniformity. As described above, it is difficult to improve the liquid efficiency by the spin coating method using the spin coating method and to achieve uniform thinning of the secondary coating film with high accuracy.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-described problems, and has been made in view of the above-described problems. In the coating device, when applying a primary coating film that has a large effect on the secondary coating film,
It is an object of the present invention to provide a rotary coating apparatus that can apply a coating liquid with a smaller amount of coating liquid without causing a central portion of the substrate rotation to have a mountain shape or an uneven state.

[0012]

According to the present invention, there is provided a coating head having a linear opening having a predetermined width in a substrate having a flat coating surface. A rotary coating apparatus that forms a primary coating film by discharging a coating liquid at a constant rate by using, and uniformly diffuses the primary coating film by centrifugal force accompanying high-speed rotation to form a secondary coating film, Holding the substrate by suction with the coating surface up, rotating and holding means for rotating, lifting and lowering means for relatively moving up and down the coating head and the rotation holding means, and applying the coating head to the rotation holding means. Centering on the rotation center,
A first coating head that applies a circular coating surface having the opening as a radius, and at least one or more adjacent annular coating surfaces that are the same as the rotation center of the circular coating surface outside the circular coating surface. While dividing into at least one or more second coating heads for coating with respect to each other, the adjacent circular coating surface and each of the annular coating surfaces are in contact at the inner circumference and the outer circumference, and when rotated by a unit, Each coating head is characterized in that the coating is performed so that the primary coating film has substantially the same thickness by the cooperation of the quantitative discharge per unit area of each locus drawn on the circular coating surface and the annular coating surface. I have.

A primary coating film is formed on a substrate having a flat coating surface by quantitatively discharging a coating liquid using a coating head having a linear opening having a predetermined width, and a primary coating film is formed by centrifugal force accompanying high-speed rotation. A rotary coating device that uniformly diffuses the primary coating film to form a secondary coating film, and holds and holds a substrate with the coating surface facing upward, and a rotation holding unit that rotates.
Elevating means for relatively elevating and lowering the coating head and the rotation holding means, and setting the coating head at the rotation center of the rotation holding means as a start position and ending at the outer periphery of a circular coating surface with the opening as a radius. Within the distance defined as the position, and within the distance defined as the end point, the outer circumferential circle of the annular coating surface having the same coating area as the circular coating surface with the start position being a position substantially along the tangential direction of the circular coating surface, per unit time Coating head moving means for controlling the moving speed of the coating head and driving the coating head so that the coating effective area is substantially constant,
By rotating the substrate by the rotation holding means and cooperating with the quantitative discharge of the coating liquid accompanying the movement of the coating head at the moving speed, the coating is performed so that the primary coating film has substantially the same thickness. I have.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an external perspective view showing the entire configuration of the rotary coating apparatus 1. As shown in FIG. FIG. 2 is a plan view (a), a front view (b), and (c) showing the positional relationship between the rotary table 4 and the coating head 5 shown in FIG.

In FIG. 1, a flat substrate 3 such as a semiconductor substrate, a liquid crystal glass substrate, a printed substrate, and a plasma display is separately mounted on a pair of forks 16 as shown in FIG. A desired coating film is formed by exchanging between the apparatuses. Base 2 of this device 1
Above, a main body side of a motor 11 described later is fixed. A rotary table 4 is provided at an upper opening of the apparatus 1 and is rotated at low and high speeds in the direction of the arrow by receiving power from the output shaft of the motor 11 or a motor (not shown). The rotary table 4 has a flat circular suction surface as shown in the drawing, and the substrate 3 is suction-held by supplying a vacuum pressure from the vacuum generator 15 via the valve 14 on the suction surface. Countless suction holes 4 for
a is provided.

The vertical movement is carried out by a lifting operation of a lifting motor 12 fixed to the base 2.

With the above configuration, the rotating table 4 is moved up and down relatively with respect to the coating head 5 disposed above, so that coating, which will be described later, is performed and the substrate 3 is retracted after the coating head 5 is retracted. Fork 16 of robot device (not shown)
It is configured so that it can be placed and transferred on top.

On the outer peripheral side of the rotary table 4, there is provided a collecting case 9 for preventing and recovering excess coating liquid which is scattered due to the high-speed rotation of the rotary table 4.

On the other hand, as shown in the figure, five identical coating heads 5 are provided with a pipe for introducing a coating liquid supplied from a coating liquid supply device 6 via a valve 7 and a coating head 5 immediately after coating.
A pipe connected to a sack valve 8 that forcibly sucks the coating liquid from the inside is provided to enable coating described later. The above-described valves and motors are connected to the control device 10 and are configured to operate in conjunction with each other based on an instruction from the control device 10.

Next, the arrangement of each coating head 5 and the principle of coating will be described with reference to FIG.

The first coating head 5A has one end located at the rotation center O and an opening having a width h in the y direction. As a result, when the rotary table 4 is rotated by 360 degrees in the direction of the arrow, a circular application surface a having an area of πh ² with the opening as a radius is applied.

Next, the opening is arranged substantially along the tangential direction of the circular coating surface a to make the circular coating surface a an inscribed circle,
First annular coating surface b having the same coating area as circular coating surface a
A second coating head 5B for coating is provided as shown.

The coating area applied by the second coating head 5B can be obtained from the calculation formula in the drawing by the right triangular Pythagorean theorem, so that the area is the same as πh ² which is the area of the circular coating surface a. Is the first annular coating surface b having an area of πh ² .

Further, the opening is arranged so as to be substantially tangential to the outer circumferential circle of the first annular coating surface b, so that the outer circumferential circle of the first annular coating surface b has an inscribed circle. A third coating head 5C for coating the second annular coating surface c is further provided.

Hereinafter, the opening is similarly formed on the second annular coating surface c.
The fourth coating head for coating the third annular coating surface d having the outer circumferential circle of the second annular coating surface c as the inscribed circle by arranging the opening portion substantially in the tangential direction of the outer circumferential circle of 5D,
The opening is arranged so as to substantially follow the tangential direction of the outer circumferential circle of the third annular coating surface d, so that the outer circumferential circle of the third annular coating surface d is an inscribed circle. A fifth coating head 5E for coating e is provided.

As described above, the same coating head 5 is moved to x in FIG.
Arrange so as to translate in the axial direction. When each of the above coating heads 5A to 5E is rotated once while applying a coating fluid as a slot nozzle capable of quantitative discharge with the same length and the same opening width, all the coating is performed in the same amount. The circles a, b, c, d and e drawn on the disk P are each coated with a coating head as shown in FIG.
As shown in (b), each of a, b,
The average film thicknesses of the coating liquids applied to the coating surfaces of c, d, and e are substantially equal.

As a result, the average thickness T was averaged so as to be incomparable with FIG. 2 (c), which is the film thickness distribution shown by the broken line when the coating was performed by the conventional coating head 105 shown by the broken line for comparison. A primary coating film can be formed, and thereafter a high-speed rotation can be performed to form a uniform coating film, and the amount of excess coating liquid is extremely reduced.

That is, when a slot having a radius or diameter of one coating area is arranged at the center of rotation at the end or center thereof and applied to the rotating substrate, the film thickness distribution shown by the broken line is represented by the outer peripheral portion. In this case, the difference is remarkably different when the gradient is made equal to the gradient of the coating film formed on the substrate (the gradient of the annular circle e in the present invention).

[0030] In this manner, by applying a coating by an equal-amount discharge coating head that can divide the effective coating surface into equal areas, it is possible to apply a thin film having approximately the same thickness. Further, although the drawings show that the openings of the coating head are arranged orthogonally along the tangential direction, they may be inclined with respect to the y-axis.

FIG. 3 is a sectional view of the coating head 5.
FIG. 2A is a cross-sectional view cut along the longitudinal direction of the opening, and FIG. 2B is a vertical cross-sectional view cut off orthogonal to the opening.

In FIG. 3, each of the coating heads 5A to 5E has three spacer members 1 having different thicknesses as shown.
7 are completed with bolts and nuts (not shown) interposed therebetween. After completion, a flow path 18 is formed, which communicates with each other and is connected to the inlet and outlet of the supply device 6 and the sack valve 8. The coating liquid is supplied stably into the space 19 of each coating head in the same manner by the channels and 18. The space 19 communicates with the opening of the slot 20 so that the same amount can be discharged from the tip in the direction of the arrow.

As described above, each coating head has a width W
It is possible to communicate with the opening of the slit 20 forming a slot having a width (h) of the opening and having a length substantially equal to the opening length at the upper part of the opening so that the pressure fluid can be sent out stably to the slot. it can. As a collective coating head in which a plurality of such coating heads and the coating heads are arranged at appropriate intervals, the supply timing of the coating liquid is controlled by turning on / off a valve. An open / close valve is also provided at the outlet. When the slot gap is sufficiently narrow and the height of the slot is sufficiently high, the valve of the discharge port is opened and the liquid is supplied from the inlet (atmospheric pressure). It is full of 19 and reaches the outlet.

Then, when the open / close valve of the discharge port is closed, the liquid is discharged from the end of the slot. By repeating this several times, it is possible to create a state in which the coating head is filled with a liquid having no air bubbles. Then, when the on-off valve of the supply unit is closed and the liquid is sucked by the sack valve provided at the end of the on-off valve of the discharge unit, the liquid at the tip of the discharge opening can be drawn into the slot. Close the open / close valve. In this state, the apparatus enters a standby state in which the application operation can be started. In addition, any means may be used as long as the fluid is supplied to the supply port at a constant pressure.

Coating is performed while the coating head is relatively raised and lowered in order to set a gap between the tip of the opening of the coating head having the above configuration and the coating surface of the rotating substrate at a predetermined value. It is better if the supply valve is opened immediately after the application liquid seeps out to the tip of the application head and small liquid droplets are continuously formed.

In this manner, the coating is performed until the substrate 3 rotates 360 degrees or more, and when the rotation angle reaches a predetermined rotation angle, the opening / closing valve 7 provided in front of the liquid inlet is closed, and the liquid is discharged from the liquid outlet. The suction is performed, and the application head or the substrate 3 to be applied is moved up and down by the elevating means. On the coating surface formed in this way, a small rippled coating film corresponding to the number of coating heads to be installed is formed, and the average film thickness T between the rippled coating surfaces becomes the same thickness, so that the coating is effective. It is possible to obtain a primary coating film in which almost the entire surface is wet with the coating liquid. Thereafter, by controlling the number of rotations of the turntable 4 so that the substrate is rotated at a high speed for a predetermined time, a secondary coating film having a desired uniform film thickness can be obtained.

Here, as described above, by setting the width of the opening of each coating head in the collective coating head to be the same as the radius, the coating head having the opening corresponding to the diameter of the rotary table as in the prior art. Since the portion for ensuring the linearity of the tip of the slit opening is shorter than in the case of the manufacturing method, the manufacturing process is greatly simplified.

FIGS. 4A to 4E are layout diagrams of the coating head. In the drawing, the above-described arrangement is such that one end of the opening located at the center is positioned at the center of rotation, and the openings of the slots are sequentially arranged so as to substantially circumscribe the circle drawn by the other end. The width dimension h of the opening of the central slot is the radius of the circle to be drawn. In theory, the primary coating film could be formed in a rippled state as described above. FIG. 4B shows that the width of the opening of each coating head 5 is h1.
The extra large opening width is provided, so that the overlapping portion of the ripples can be made more uniform. In FIG. 4C, the width of the opening is set to 2 h, and the diameter of the circle drawn when the center of the central slot opening is located at the center of rotation is set. FIG.
(D), the width dimension of the slot opening at the center of the coating head is 2h, which is twice that of the other coating heads, and the coating head having the width dimension h at a point symmetric position about the rotation center point. Are arranged for two sets. Then, FIG.
Sets the width of the slot opening at the center of the coating head to 2h, which is twice that of the other coating heads, and places the coating head of the opening having the width dimension h at a line symmetrical position of the opening of the center coating head. Two sets are arranged.

By disposing the coating head as shown in FIGS. 4 (d) and 4 (e), the rotation angle at the time of coating was required to be 360 ° or more in FIGS. 4 (a) to 4 (c). , 1
It is sufficient if the angle is 80 degrees or more.

It should be noted that the slot opening located at the center of the coating head having the above-described configuration is not necessarily arranged in parallel with other slot openings, and that the principle is not changed even if an angle is provided or the slot opening is orthogonal. Needless to say.

Next, FIG. 5 (a) shows a coating circle drawn by each coating head when the coating head 5 shown in FIG. 5 performs coating on a rectangular substrate 3 as shown. FIG. 3 is a diagram illustrating a state of a substrate. FIG. 5B is a diagram in which the coating head 5D and the coating head 5E are removed and the coating head 5C is extended, and FIG. 5C is a diagram in which the coating head 5C is doubled.

5A and FIG. 5C, a comparison is made between the liquid discharge amounts consumed in one-cycle coating operation. Assuming that the coating amount in FIG. 5A is "5", FIG. Then, it becomes "4". Further, since the coating head 5C in FIG. 5C partially protrudes outside the annular coating surface e, if the coating head 5C is accommodated in the annular coating circle e, as shown in FIG. Amount. The coating head 5C shown in FIG. 5B has annular circles c, d, and e.
Although the average coating thickness on the circular coating surface a and the circular coating circle b is the same and the average coating thickness on the annular coating surface c is slightly thicker, the annular coating surfaces a and b
Is equal to

In the annular coating surfaces d and c, the coating head 5C
Is applied to the substrate at the openings of δ and η, but the effective area of application on the substrate 3 is a fraction of the annular coating surface d, and is several tenths of the annular coating surface e. Become. That is, as shown in the example of FIG. 5B, by setting the length of the coating head 5C to an appropriate length, coating with high liquid efficiency can be realized.

In the example of FIG. 5B, the coating head 5C
However, depending on the size of the substrate 3 and the length of the opening, both ends of the coating head 5C are appropriately extended or the arrangement of the coating head 5C is moved toward the coating head 5B, so that the coating film on the outer peripheral portion is thickened. It can be spread and spread at high speed. Needless to say, the number of coating heads 5, the width of the opening, the liquid supply pressure, and the like are appropriately selected from the shape and size of the substrate, the desired thickness of the film, the viscosity of the liquid to be coated, and the like.

The length of the opening of the coating head 5 is determined by sandwiching a shim 21 between two wall surfaces and tightening with a bolt 22 as shown in the cross-sectional view and the vertical cross-sectional view (b) of FIG. By forming 5, the opening length and the opening position, and the opening width W can be easily changed by shim exchange. Of course, it goes without saying that the shims of all the coating heads constituting the coating head have the same thickness.

Next, FIG. 7 is a plan view showing the principle of operation of the rotary coating apparatus according to the second embodiment. FIG. 8 is a front view showing the movement of the coating head, showing a standby position (a), a coating start position (b), and a substrate removal position.

First, the components already described in FIG. 8 are denoted by the same reference numerals and description thereof will be omitted. Only one coating head 5 is mounted on a head moving elevating mechanism not shown in FIG. I have. A distance sensor 26 is fixed to the coating head 5, moves while measuring the distance between the substrate 3 and the opening, and moves as shown in FIG.
It is configured so that application can be performed in accordance with the upward movement. Further, the rotary table 4 fixed to the upper end of the ball spline shaft 30 (shown by a broken line) serving as the output shaft of the above-described motor 11 is moved upward along with the energization of the lifting motor 12 as shown in FIG. At the position shown in FIG. 8C, the pair of forks 16 of the robot device (not shown) is placed on the side surface of the outer peripheral surface of the rotary table 4 and under the substrate 3 so that the substrate 3 can be placed. Have been.

In FIG. 7, the width of the opening of each coating head 5 is equal, and one end of the coating head 5A is arranged at the center of rotation, and the other end is applied to the outer peripheral surface of the circular coating surface a. However, at this time, the ratio of the distance between the coating heads 5A to 5E is as follows from the Pythagorean theorem of a right-angled triangle when h, which is the length AB between the coating heads 5A and 5B, is "1". Become.

AB: BC: CD: DE: DF:... =
1: √2-1: √3-√2: √4-√3: √5-√4:
... Δn−Δn−1 Therefore, each distance AB, B between these coating heads
If the moving speed is controlled so that the moving time of the coating head 5 between C, CD, DE, and DF is equal, the coating speed can be reduced under the condition that the discharge amount of the coating head per unit time and the substrate rotation speed are constant. .. Will be constant over substantially the entire surface a, b, c, d,. Therefore, FIG.
, The movement control of the same application head 5 is performed so that the locations indicated by the broken lines are set as the base point and the end point. However, there is some variation near the application start point and the application end point.

There are two types of coating operations described above, including a method of starting coating from the center of rotation and a method of starting coating from the outer periphery. In the case of starting from the center of rotation, as shown in FIG. 7B, from the upper standby position P1 of the substrate 3 rotating at a low speed, the application head is moved obliquely at a high speed while lowering the application head while starting liquid discharge. The coating liquid is landed on the surface of the substrate 3 at a position P2 before the rotation center, and deceleration control is performed from the rotation center position to the end point to perform coating. The end point position may be inside the substrate or outside the substrate 3.

When starting from the outer peripheral side of the substrate 3, starting from the position E shown in FIG. 7A, the surface of the rotating substrate and the tip of the coating head are set at a predetermined gap, and the coating liquid is set. This is a method of starting ejection and moving toward the center of rotation. At the start, the coating head is in a stopped state, is gradually accelerated, and is driven so as to raise the coating head at a position where the rotation center or the center is exceeded.

When moving coating is started while controlling the speed of acceleration / deceleration on such a rotating substrate, it is possible to perform substantially uniform primary coating except for the start and end points in any of the above methods. . Thereafter, by rotating at a high speed, a desired uniform secondary coating film can be obtained.

By applying as described above, a surplus coating liquid is not required, and liquid-saving coating with high liquid efficiency can be realized. The length of the coating head 5 and the position of the coating head end may be appropriately selected, for example, as shown in FIG. 5, and a short coating head that can be manufactured at lower cost than the coating head of a conventional rotary coating device can be used. Becomes In addition, this method is not only effective as a liquid-saving coating method for a circular substrate, but also for a rectangular substrate, the liquid-saving effect is improved by appropriately controlling the speed in the vicinity of the rotation outer peripheral portion. Absent.

Here, the gap between the tip opening of the coating head and the coating surface of the substrate becomes a more important factor as the thin film coating is pursued. When applying a wet film with a thickness of several μm, the gap should be about several tens μm ± 20 μm. If it is less than this, liquids formed on the tip of the coating head and the surface of the substrate may contaminate the area other than the tip of the coating head. Nature,
In a continuous production operation, the fouling liquid may contaminate the next object.

Further, if it is larger than that, it is difficult to continuously form a curtain-shaped fluid from the coating tip to the substrate surface over the entire opening length of the coating head due to the surface tension, and the possibility of partial breakage increases. . Further, the thickness of the substrate 3 is 1
It varies from lot to lot by about 0 to 20 μm. From this,
As described above, monitoring the distance with the distance sensor 26 to detect the height of the substrate surface and setting an appropriate gap for each substrate improves the quality and liquid efficiency of the primary coating film when performing thin film coating. Important above.

The coating head used as described above does not only discharge from the slit-shaped opening as described above, but also has a large number of fine shapes as shown in FIGS. 9 (a) to 9 (c). A nozzle in which the holes 23 are provided substantially linearly may be used. That is, the state of the fluid when the fluid is ejected from the application head will be described. When the fluid in the state where the liquid tip is housed in the application head nozzle is ejected, the ejected fluid firstly has a minute hemispherical liquid droplet at the tip of the application head. Will be formed.
After forming this hemispherical liquid ball over the entire opening,
When the distance between the head tip and the substrate is reduced to a predetermined value, the liquid ball is crushed and a liquid sump film is formed continuously over the entire length of the coating head opening. When the application head or the substrate is relatively moved from this state, the crushed liquid ball (thick coating excess liquid) is stretched by the traveling operation. The liquid ball formed at the tip in this way has a diameter of 0. Several mm
It has been confirmed that the coating quality is high when the following small balls can be arranged at substantially equal intervals.

The same applies to the micropore nozzle shown in FIG. 9. When a large number of hemispherical liquid balls are formed at the tips of a large number of pinholes at the time of discharging the fluid, a predetermined gap from the substrate surface is obtained. The liquid pool can be formed over the entire length of the opening. In such a structure of the coating head nozzle, the fine holes 23 of the pinholes are arranged at a constant pitch.
FIG. 9 (a) shows that the pores are provided up to the tip as shown in FIG.
As shown in FIG. 2B, a thinner continuous coating head may be provided at the end.

With such a pore shape, the discharge portion can be formed by integral block processing, so that the production cost can be reduced and the handling can be facilitated.

The block is not necessarily integral but may be divided into two. The shape of the pores is not limited to a round hole, but may be a square hole.

As described above, by using a motor, a primary coating film that is substantially uniform and does not form a mountain at the center of the substrate can be quickly obtained with a small amount of coating solution on a substrate that rotates at a low speed. A film can be obtained and further quality improvement can be realized.

[0061]

As described above, according to the present invention,
After forming a primary coating film using a coating head, when applying a primary coating film that has a large effect on the secondary coating film in a rotary coating device that forms a secondary coating film by centrifugal force accompanying high speed rotation In addition, it is possible to provide a rotary coating apparatus that can perform coating with a smaller amount of coating liquid without causing a central portion of the substrate rotation to have a mountain shape or an uneven state.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a rotary coating device according to a first embodiment.

2A is a plan view showing the principle of the coating operation in FIG. 1,
2B is a front view of FIG. 2A and FIG. 2C is a front view showing a comparison with a conventional coating film.

3A is a cross-sectional view of a coating head, and FIG. 3B is a vertical cross-sectional view of the coating head.

FIGS. 4A to 4E are plan views illustrating the principle of a coating operation according to another embodiment.

5 (a) to 5 (c) are plan views showing the coating operation principle of another embodiment.

6A is a cross-sectional view of the coating head, and FIG. 6B is a vertical cross-sectional view of the coating head.

7A is a plan view illustrating a principle of a coating operation of a rotary coating apparatus according to a second embodiment, and FIG. 7B is an operation state diagram of a coating head.

FIGS. 8A to 8C are front views illustrating the operation of the coating apparatus.

9A is a cross-sectional view of a coating head, and FIG. 9B is a vertical cross-sectional view of the coating head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotary coating device 2 Base 3 Substrate 4 Rotary table 5 Coating head

Claims (12)

[Claims] 1. A primary coating film is formed on a substrate having a flat coating surface by using a coating head having a linear opening with a predetermined width to discharge a coating liquid, thereby forming a primary coating film, and a centrifugal force associated with high-speed rotation. A rotary coating device that uniformly diffuses the primary coating film to form a secondary coating film, thereby holding a substrate by suction with the coating surface facing upward and rotating, and the coating head. A lifting / lowering unit for relatively moving the rotation holding unit up and down; a first coating head for coating the coating head on a circular coating surface with the opening as a radius around the rotation center of the rotation holding unit. And at least one or more second coating heads that apply to at least one or more adjacent annular coating surfaces that are the same as the rotation center of the circular coating surface outside the circular coating surface. Then The adjacent circular coating surface and each of the annular coating surfaces are in contact at the inner and outer circumferences, and when rotated by a unit, each of the coating heads is drawn on the circular coating surface and each of the annular coating surfaces. A rotary coating apparatus, wherein the primary coating film is coated so as to have substantially the same thickness by the cooperation of a fixed amount discharge per unit area of the trajectory. 2. The application area of each locus drawn on the circular application surface and the annular application surface by adjusting the width and direction of the opening of the first application head and the second application head. 2. The rotary coating device according to claim 1, wherein the rotation type coating device is set equal. 3. The width of the opening of each of the first and second coating heads is made equal so that each of the second coating heads extends along the tangential direction of the inner periphery of the annular coating surface, 3. The rotary coating apparatus according to claim 2, wherein the application area of each locus drawn on the circular coating surface and each of the annular coating surfaces is made equal. 4. The first coating head and the second coating head are integrally provided, and a coating liquid supply path communicating with each of the first coating head and the second coating head is provided so as to be substantially orthogonal to the opening. 4. A collective coating head.
4. The rotary coating apparatus according to 1. 5. The rotary coating apparatus according to claim 4, wherein a width dimension of an opening of each coating head in the collective coating head is set to be larger than the radius. 6. The rotary coating apparatus according to claim 4, wherein a width dimension of an opening of each coating head in the collective coating head is set to approximately twice the radius. 7. The width of the opening of the first coating head in the collective coating head is set to approximately twice the radius, and the width of the opening of each of the second coating heads is set to the radius. The rotary coating apparatus according to claim 4, wherein the rotary coating apparatus is set and arranged at line-symmetric positions of the first coating head. 8. A primary coating film is formed by quantitatively discharging a coating liquid onto a substrate having a flat coating surface using a coating head having a linear opening having a predetermined width, and a primary coating film is formed by centrifugal force accompanying high-speed rotation. A rotary coating device that uniformly diffuses the primary coating film to form a secondary coating film, wherein the coating head is rotated while holding the substrate with the coating surface facing upward, and the coating head. Lifting means for relatively lifting and lowering the rotation holding means, and the coating head, the rotation center of the rotation holding means as the start position, the outer periphery of the circular coating surface with the opening radius as the end point position Within the distance, and within the distance with the position substantially along the tangential direction of the circular coating surface as the start position and the outer circumferential circle of the annular coating surface having the same coating area as the circular coating surface as the end point, the coating is effective per unit time. The area is almost constant And a coating head moving means for controlling the moving speed of the coating head to drive the substrate sequentially. The rotation of the substrate by the rotation holding means and the quantitative discharge of the coating liquid accompanying the movement of the coating head at the moving speed. The first coating film is applied so as to have substantially the same thickness in cooperation with each other. 9. The rotary coating apparatus according to claim 8, wherein an annular coating surface located on the outer peripheral side of the circular coating surface is further applied. 10. A detecting means for detecting a distance to the coating surface, wherein a gap between a tip of a discharge part of a coating head of the coating head moving means and the coating surface can be set to a predetermined gap by the elevating means. 9. The rotary coating device according to claim 8, wherein the coating is performed. 11. The rotary coating apparatus according to claim 1, wherein the opening is a slit nozzle communicating with a flow path. 12. The rotary coating according to claim 1, wherein the opening is a nozzle provided with a large number of fine holes communicating with a flow path in a substantially straight line. apparatus.