JPH0985156A - Rotary coating device for substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such a rotary coating device for a substrate that the amt. of a coating liquid supplied to obtain a coating film of desired film thickness can be decreased to an extremely small amt. by designing a supply nozzle of a coating liquid to have a proper horizontal cross section. SOLUTION: The nozzle part 41 consists of a discharge hole 47 octagonal in the horizontal cross section and a lower face 41a of the nozzle. A photoresist liquid fed under pressure through the passage 42 of a supply nozzle of a coating liquid is discharged as in an almost hexagonal shape onto the substrate surface. The photoresist liquid dropped on near the rotational center of the substrate produces wide whisker-like lines which extend from each vertex while lines are curved to the tangential direction. Also the photoresist produces lines extending straight between the wide lines. The space among these lines can be rapidly narrowed by the interaction of these lines.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for applying a coating liquid such as a photoresist liquid onto a substrate such as a semiconductor wafer, a glass substrate for a photomask, a glass substrate for a liquid crystal display device, a substrate for an optical disk and the like. In particular, while the substrate is rotated at a low speed at a predetermined rotation speed, the coating liquid is spread over the entire surface of the substrate by supplying the coating liquid near the center of rotation, and then the substrate is rotated at a high speed at a predetermined rotation speed. The present invention relates to a technique for forming a coating film having a desired film thickness on the surface of a substrate.

[0002]

2. Description of the Related Art A conventional rotary substrate coating apparatus of this type will be described with reference to FIG. This drawing shows the main part of a rotary substrate coating apparatus, which is a suction spin chuck 10 for supporting a substrate W by suction and rotating it in a substantially horizontal posture.
A coating liquid supply nozzle 30 for supplying a photoresist liquid, which is an example of the coating liquid, to the surface of the substrate W is provided substantially above the center of rotation. The coating liquid supply nozzle 30 has a discharge hole that opens toward the lower substrate W and has a horizontal cross-sectional shape that is substantially circular.

In the apparatus thus constructed, the rotation speed is controlled as shown in the time chart of FIG. 11 to obtain a photoresist film having a desired film thickness on the surface of the substrate W.

That is, first, the suction type spin chuck 1
The substrate W is rotated by a motor (not shown) to rotate the substrate W at a predetermined rotation speed R1 (for example, 900 rpm). When the rotation becomes stable, the coating liquid supply nozzle 30
Then, the photoresist solution R is started to be discharged at a substantially constant flow rate (reference numeral t _{S in} FIG. 11), and the photoresist solution R is continuously supplied to the vicinity of the rotation center of the substrate W. Then, the supply of the photoresist solution R is stopped at a time point (reference numeral t _{E in} FIG. 11) after a predetermined time has elapsed from the time point t _S at which the supply of the photoresist solution R is started. After that, the rotation speed of the suction spin chuck 10 is increased to a rotation speed R2 (for example, 3,000 rpm) higher than the current rotation speed R1 and kept at the rotation speed R2 for a predetermined time, so that the surplus power supplied to the surface of the substrate W is increased. The photoresist solution R is shaken off, and a photoresist film having a desired film thickness is formed on the surface of the substrate W.

In the conventional device as described above, FIG.
A photoresist film is formed by the behavior of the photoresist liquid R as shown in the schematic diagrams of 2 (a) to 12 (f). In these figures, the substrate W is simply indicated by a circle, and the photoresist liquid R is indicated by a hatched region.
The number of rotations of the substrate W in each figure is schematically shown by the size of the arrow.

First, in a state immediately after the supply of the photoresist liquid R to the surface of the substrate W while the substrate W is being rotated at a low speed at the rotation speed R1, the photoresist liquid R has a circular mass R _a ( hereinafter, this is referred to as the core R _a) to be in the vicinity of the rotation center of the substrate W becomes. Further, the photoresist solution R
When the core R _a is continuously supplied, the diameter of the core R _a expands concentrically toward the peripheral edge of the substrate W while maintaining a substantially circular shape due to the centrifugal force accompanying the rotation.

[0007] During the core R _a is some time (a few seconds) is being kept circular, will transform then largely shape. Specifically, the circular flow of the core R _a number of elongated photoresist solution R _b from the circumference portion toward the peripheral portion of the substrate W (hereinafter, referred to as whiskers R _b) is radially extending Start (FIG. 12 (a)). The large number of mustaches R _b continue to extend toward the peripheral edge of the substrate W due to the expansion of the diameter of the core R _{a due to} the centrifugal force, but the beard R _b has _a larger radius of rotation than the core R _a , and therefore the centrifugal force is increased. Since the force acts strongly, the core R _a extends toward the peripheral edge of the substrate W faster than the diameter of the core R _a increases (FIG. 12B).

Further, the rotation of the substrate W is continued at the rotation number R1 (at this time, the photoresist liquid R is also supplied).
Then, the tips of the many mustaches R _b reach the peripheral portion of the substrate W (FIG. 12C). When a large number of whiskers R _b reach the peripheral portion of the substrate W in this way, the photoresist liquid R reaches the peripheral portion of the substrate W from the core _Ra through the beard R _b and is scattered (scattered photoresist liquid R _c ). To do. Furthermore, as the diameter of the core R _a increases, the width of the beard R _b increases (FIG. 12).
By the alternate long and two short dashes line in (c) and FIG. 12 (d), the area between the beards R _b not covered with the photoresist solution R is gradually reduced and the entire surface of the substrate W is covered with the photoresist solution R.
(Core R _a , mustache R _b ) (FIG. 12)
(E)). At this point, the time is set in advance to stop the discharge of the photoresist liquid R from the coating liquid supply nozzle 30 (reference numeral t _{E in} FIG. 11).

As described above, after the entire surface of the substrate W is covered with the photoresist solution R, the surface of the substrate W is covered with the rotational speed of the substrate W set to a rotational speed R2 higher than the current rotational speed R1. A surplus photoresist solution R (surplus photoresist solution R _d ) is shaken off to form a photoresist film R ′ having a desired film thickness on the surface of the substrate W (FIG. 1).
2 (f)).

[0010]

However, the above-mentioned conventional device has the following problems. That is,
As shown in FIG. 12C, when many mustaches R _b reach the peripheral edge of the substrate W, most of the photoresist solution R supplied thereafter passes from the core _Ra to the mustache R _b. It is discharged around the substrate W and scattered (scattered photoresist liquid R _c ). Therefore, it is necessary to supply a large amount of the photoresist solution R before the entire surface of the substrate W is covered with the photoresist solution R, and there is a problem that the usage of the photoresist solution becomes extremely large. That is, there is a problem that the utilization efficiency of the photoresist solution R is extremely low when obtaining a photoresist film having a desired film thickness.
Incidentally, since the coating liquid such as the photoresist liquid is very expensive compared to the processing liquid such as the developing liquid and the rinsing liquid, it is necessary to reduce the amount of the unnecessary coating liquid which is scattered in the manufacturing of semiconductor devices and the like. This is an important issue in reducing costs.

The present invention has been made in view of such circumstances, and by devising the horizontal cross-sectional shape of the coating liquid supply nozzle, the coating liquid supplied to obtain a coating film having a desired film thickness can be obtained. It is an object of the present invention to provide a rotary substrate coating apparatus capable of extremely reducing the amount.

[0012]

The present invention has the following configuration in order to achieve the above object. That is, the rotary substrate coating apparatus according to claim 1 supplies the coating liquid to the vicinity of the rotation center of the substrate through the coating liquid supply nozzle while rotating the substrate at a predetermined rotation speed at low speed by the rotation support means, and thereafter. In a rotary substrate coating apparatus for forming a coating film having a predetermined film thickness on a substrate surface by rotating the rotation speed at a high speed at a predetermined rotation speed, the coating liquid supply nozzle has at least a discharge hole and a horizontal cross-sectional shape thereof. Is characterized by being formed into a non-circular shape.

Further, in the rotary substrate coating apparatus according to the second aspect of the present invention, while the substrate is rotated at low speed by the rotation supporting means at a predetermined number of rotations, the coating liquid is supplied near the center of rotation through the coating liquid supply nozzle. Then, in the rotary substrate coating apparatus for forming a coating film having a predetermined film thickness on the substrate surface by subsequently rotating the rotation speed at a predetermined rotation speed, the coating solution supply nozzle has at least a nozzle lower surface outer shape, It is characterized in that it is formed in a non-circular shape in the horizontal sectional shape.

A rotary substrate coating apparatus according to a third aspect of the present invention is the rotary substrate coating apparatus according to the first or second aspect, wherein the horizontal sectional shape is a polygon. It is a thing.

A rotary substrate coating apparatus according to a fourth aspect is the rotary substrate coating apparatus according to the first or second aspect, wherein the horizontal cross-sectional shape is an octagon. It is a thing.

[0016]

The operation of the invention described in claim 1 is as follows. While the substrate is rotated at a low speed by the rotation support means at a predetermined speed, the coating liquid is supplied to the vicinity of the center of rotation through the coating liquid supply nozzle, and the substrate is rotated at a predetermined rotation speed higher than the rotation speed at the low speed rotation. By rotating at high speed, a coating film having a desired film thickness is formed on the surface of the substrate. The coating liquid supply nozzle that supplies the coating liquid to the substrate surface has at least the discharge holes.
Since the horizontal cross-sectional shape is non-circular, if the coating liquid supplied to the substrate surface has a relatively high viscosity, the coating liquid is discharged at the moment of dropping, for example, as shown in the schematic diagram of FIG. The droplets are in a non-circular shape that is almost the same as the shape of the holes. That is, the coating liquid R is positioned in the vicinity of the center of rotation in a state where the coating liquid R has a non-circular shape and forms the core _Ra '(hatched area in the figure).

The non-circular core R _a 'behaves as shown in the schematic view of FIG. 5 as the substrate W rotates. That is, the portion of the non-circular core R _a 'close to the peripheral edge of the substrate and the portion distant from the peripheral edge of the substrate, in other words, the portion with the long radius of rotation and the portion with the short radius of rotation, naturally have the longer radius of rotation. However, since it receives a large centrifugal force as compared with a portion having a short radius of gyration, first, a wide coating liquid flow from those portions of the non-circular core R _a 'to the peripheral edge of the substrate W. (hereinafter, referred to as wide beard R _e) (indicated by the two-dot chain line in the figure) starts to stretch. Then, from between the beard R _e each wide, a radial flow of the coating solution shown in prior art beard R _b (indicated by a dotted line in the drawing) begins to stretch.

Since a large number of wide beards R _e contain a large amount of coating liquid [because they are so wide] as compared to the beards R _b , they are strongly subjected to an inertial force, so that they linearly extend toward the peripheral edge. Instead, it extends while being bent in the circumferential direction of the substrate, while the large number of whiskers R _b linearly extend toward the peripheral edge of the substrate. In addition, the diameter of the core R _a 'is also expanded along with these expansions. The interaction between these linearly extending beard R _b and the wide beard R _e that is extended while being bent in the circumferential direction results in the beard R _b and the wide beard R _e.
The gap not covered with the coating liquid [between the beard R _b and the wide beard R _e ] is rapidly narrowed by the time when the coating liquid R reaches the peripheral portion of the substrate W, until the coating liquid R covers the entire surface of the substrate W. The time (coating required time) can be shortened. The short coating time means that the time from when the supply of the coating liquid is started to when the coating liquid covers the entire surface of the substrate W and the supply of the coating liquid is stopped is short. In other words,
Beard R _b and wide beard R _e is short time until the supply of the coating solution from reaching the peripheral portion of the substrate W is stopped, the substrate W correspondingly through the whiskers R _b and wide beard R _e Since the amount of the coating liquid scattered from the peripheral portion is small, the amount of the coating liquid required to obtain a coating film having a desired film thickness can be reduced.

The operation of the invention described in claim 2 is as follows. While rotating the substrate at a low speed with a predetermined rotation speed by the rotation support means, the coating liquid is supplied to the vicinity of the rotation center through a coating liquid supply nozzle, and the substrate is rotated at a high speed at a predetermined rotation speed higher than the rotation speed at the low speed rotation. By doing so, a coating film having a desired film thickness is formed on the surface of the substrate. Since the outer shape of the lower surface of the coating liquid supply nozzle that supplies the coating liquid to the substrate surface is formed in a non-circular shape in the horizontal cross-sectional shape, the coating liquid supplied to the substrate surface has a relatively low viscosity and is dropped. At the moment of the application, the surface tension spreads over the entire lower surface of the nozzle to form a non-circular shape which is the outer shape of the nozzle, and the droplet is dripped in a non-circular shape substantially the same as the outer shape. That is, the coating liquid R is positioned in the vicinity of the center of rotation in the state where the coating liquid R has a non-circular shape and forms the core _Ra '(hatched area in FIG. 5). The behavior in this case is the same as that of claim 1 described above, and thus the description thereof is omitted.

The operation of the invention described in claim 3 is as follows. That is, since the horizontal cross-sectional shape of the coating liquid supply nozzle is formed in a polygonal shape, the coating liquid supplied to the substrate is positioned in the vicinity of the center of rotation and forms a core in a state in which the coating liquid has substantially that shape. Since the core has a polygonal shape, a plurality of apexes on the outer periphery of the core have a long distance from the center of the core, and therefore are subjected to a stronger centrifugal force than parts other than the apex. Therefore, first of all, a wide mustache grows from each apex, a beard grows from each of those gaps,
Due to these interactions, the gap between the beard and the wide beard is rapidly narrowed, and the time required for the coating liquid to cover the entire surface of the substrate (coating required time) can be shortened. As a result, the time from when the beard and the wide beard reach the peripheral portion of the substrate until the supply of the coating liquid is stopped is shortened,
Since the amount of the coating liquid scattered from the peripheral portion of the substrate through the beard and the wide beard is reduced by that much, the amount of the coating liquid required to obtain a coating film having a desired film thickness can be reduced.

The operation of the invention described in claim 4 is as follows. The horizontal cross-sectional shape of the coating liquid supply nozzle does not have to have any number of vertices as long as it is polygonal. For example, a triangle or a quadrangle of a polygon has a small number of vertices and a wide beard. Since the number of occurrence is small, it takes time to narrow each gap due to the interaction with the beard,
On the other hand, a polygon exceeding an octagon has too many vertices, the properties of the beard and the wide beard are almost the same, and the action close to the circular core described in the conventional example occurs, After all, it takes time to narrow each gap due to the interaction.

Therefore, by forming the coating liquid supply nozzle to have an octagonal horizontal cross-sectional shape, it is possible to preferably cause an interaction with the whiskers while maintaining the characteristics of the wide beard. As a result, the time required for coating can be shortened, and the time from when the beard and the wide beard reach the peripheral edge of the substrate to when the supply of the coating liquid is stopped is shortened, and the beard and the wide beard are passed through accordingly. Since the amount of the coating liquid scattered from the peripheral portion of the substrate is reduced, the amount of the coating liquid required to obtain a coating film having a desired film thickness can be reduced.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view showing a rotary substrate coating apparatus according to an embodiment.

In the figure, reference numeral 10 is a suction type spin chuck which sucks and supports the substrate W in a substantially horizontal posture. This suction-type spin chuck 10 has a hollow rotating shaft 1.
1 and is rotationally driven by a rotary motor 12. Around the suction type spin chuck 10, a scattering prevention cup 13 for preventing scattering of a coating liquid such as a photoresist solution is arranged. In addition, when the transfer means (not shown) places the unprocessed substrate W on the suction-type spin chuck 10 or receives the processed substrate W from the suction-type spin chuck 10, the lifting means (not shown) is connected to the rotating shaft 11. The suction-type spin chuck 10 is moved above the scattering prevention cup 13 by moving the scattering prevention cup 13 up and down relative to the scattering prevention cup 13 (two-dot chain line in the figure).

The shatterproof cup 13 includes an upper cup 14 and
It is composed of a circular current plate 15 and a lower cup 17. The upper cup 14 has an opening 14a at an upper portion and an inclined surface 14b for guiding droplets such as a photoresist solution due to rotation of the substrate W downward.

The circular straightening plate 15 lowers the airflow flowing from the opening 14a and flowing down along the peripheral edge of the substrate W.
And the inclined surface 1 of the upper cup 14
The droplets such as the photoresist liquid guided downward by 4b are put on this airflow and guided to the lower cup 17.

A drain port 17a is provided at the bottom of the lower cup 17. The drain port 17a is connected to the drain tank 17
b, and is adapted to collect the photoresist solution and the like after the spin-off. At the bottom of the lower cup 17, a cup exhaust port 17c is further provided.
The cup exhaust port 17c is connected to an exhaust pump 17d, and sucks and exhausts the mist-like photoresist liquid or the like staying in the scattering prevention cup 13 together with air.

Inside the circular rectifying plate 15, there is a back rinse nozzle 20 for ejecting the cleaning liquid for removing the photoresist liquid and the mist adhering to the back surface of the substrate W toward the back surface of the substrate W. It is arranged. The back rinse nozzle 20 includes a pipe joint 18 and a supply pipe 18a.
The cleaning liquid is supplied from the cleaning liquid supply unit 18b via the.

Further, the opening 14 of the scattering prevention cup 13
above a and substantially above the center of rotation of the substrate W,
A coating liquid supply nozzle 40 that discharges the photoresist liquid is provided. The tip of the coating liquid supply nozzle 40 is directed toward the lower substrate W, and the nozzle 41 is attached to the tip.

Next, the coating liquid supply nozzle 40 and the nozzle portion 41 will be described with reference to FIGS.
2 is a vertical sectional view of the vicinity of the tip of the coating liquid supply nozzle 40 and the nozzle portion 41, and FIG. 3 is a view of the nozzle portion 41 seen from below.

The coating liquid supply nozzle 40 has a coating liquid passage 42 having a predetermined inner diameter therein, and a ring-shaped recess 43 having an inner diameter larger than the inner diameter of the coating liquid passage 42 is formed below the coating liquid passage 42. ing. This ring-shaped recess 43
An O-ring 44 is fitted in. Further, an inner screw portion 45 for attaching the nozzle portion 41 is formed below the ring-shaped recess 43. This internal thread 4
The outer threaded portion 46 formed on the upper side surface portion of the nozzle portion 41 is screwed onto the nozzle 5, so that the nozzle portion 41 can be attached to the tip portion of the coating liquid supply nozzle 40.

The nozzle portion 41 is formed with a discharge hole 47 having an octagonal horizontal cross section and a lower surface 41 a of the nozzle portion, and the photoresist liquid pressure-fed through the coating liquid passage 42 of the coating liquid supply nozzle 40 is The material is ejected onto the surface of the substrate W in almost that shape. As will be described later, various horizontal cross-sectional shapes can be adopted for the discharge holes 47 of the nozzle portion 41 and the nozzle portion lower surface 41a, and the substrate W
The nozzle portion 41 is configured to be replaceable with a nozzle section 41 having an optimum horizontal cross-sectional shape according to the size, surface state thereof, coating processing conditions (so-called recipe), and the like.

Further, a coating liquid supply means (not shown) for supplying a predetermined amount of the photoresist liquid to the coating liquid supply nozzle 40, an elevating means (not shown) for moving up and down the suction type spin chuck 10 and the scattering prevention cup 13, and rotation. Motor 12
And are configured to be controlled by the control unit 50. The control unit 50 is stored in the memory 51,
Each of the above parts is controlled by a program according to a time chart described later.

Next, the time chart of FIG. 11 and FIG.
The photoresist coating process will be described with reference to (a) to (g). The program corresponding to this time chart is stored in the memory 51 shown in FIG. 1 and executed by the control unit 50. Also, the substrate W to be processed
Is already placed on the suction type spin chuck 10 and held by suction, and the nozzle portion 41 of the coating liquid supply nozzle 40 is located above the rotation center of the substrate W. In the schematic view of FIG. 4, the substrate W is simply represented by a circular shape, the dropped photoresist liquid is represented by a hatched region, and the size of the rotation speed of the substrate is represented by the size of an arrow.

First, the rotary drive of the rotary motor 12 is started. More specifically, the control unit 50 rotates the substrate W in the “counterclockwise direction” in plan view by driving the rotation motor 12 to rotate in the normal direction. The rotation speed R1 at this time is, for example, 900r.
pm.

Next, after the rotation of the substrate W stabilizes at the rotational speed R1 (after several seconds), at the time t _s , the nozzle portion 41 of the coating liquid supply nozzle 40 starts discharging the photoresist liquid onto the surface of the substrate W. . At this point, the photoresist liquid supplied through the octagonal ejection hole 47 has a substantially octagonal shape in plan view near the rotation center of the substrate W while the contour of the ejection hole 47 is substantially maintained. Lump R _a '(Hereafter,
This is referred to as the core _Ra ') (Fig. 4
(A)).

When the photoresist solution is further supplied near the center of rotation of the substrate W, the shape of the core R _a 'changes greatly as follows. This octagonal core _Ra '
From each of the eight apexes toward the peripheral edge of the substrate W,
A wide flow of the photoresist solution R _e (hereinafter, referred to as wide beard R _e ) begins to expand (FIGS. 4B and 5). The wide beard R _e begins to extend from each apex portion of the octagonal core R _a 'because the distance from the rotation center of the substrate W is longer than the portion other than the apex, and thus a stronger centrifugal force is applied. . Beard R _e of these wide, since the amount of the photoresist solution contained therein is large, instead of linearly extending toward the peripheral portion of the substrate W, opposite to the rotation direction under the high inertial forces The core R _a 'expands faster than the diameter of the core Ra while bending in the circumferential direction while expanding its width in the direction of.

Further, a large number of elongated photoresist solutions R _b (hereinafter, referred to as beard R _b ) radiate from each gap of the eight wide beards R _e extending from the core R _a ′. It begins to grow (Fig. 4 (c), Fig. 5). The large number of mustaches R _b continue to linearly extend toward the peripheral edge of the substrate W as the diameter of the core R _a 'expands due to the centrifugal force.
Since the beard R _b has _a larger centrifugal force than that of the core R _a ′, the beard R _b moves toward the peripheral edge of the substrate W faster than the diameter of the core R _a ′ and expands together with the wide beard R _e (Fig. 4 (d)).

At this time, as shown in FIGS. 4 (c) and 4 (d), a beard R _b extending linearly on the peripheral edge of the substrate W and a wide beard R _e extending while being bent in the circumferential direction are mutually present. Due to the action, a gap which is not covered with the photoresist liquid R [between the beard R _b and the wide beard R _e ] until the beard R _b and the wide beard R _e integrally reach the peripheral portion of the substrate W. Narrows rapidly.

Then, as shown in FIG. 4D, when the tips of the integrated beard R _b and wide beard R _e reach the peripheral edge of the substrate W, the photoresist liquid R is formed around the substrate W. Scatter (scatter photoresist liquid R _c ). However, by wide beard R _e are bent in the circumferential direction, beard R _e core R _a / beard R _b / wider to toward the peripheral portion of the substrate W to expand / extension together , The time until the entire surface of the substrate W is covered with the photoresist solution R is significantly shortened as compared with the conventional case (FIG. 4).
(D), (e), (f)). In this way, when the entire surface of the substrate W is covered with the photoresist liquid R (time t _E 'in FIG. 11), the control unit 50 stops the discharge of the photoresist liquid R from the coating liquid supply nozzle 40. .

Then, as shown in FIG. 11, the rotation speed R1
The surface of the substrate W is rotated by continuing the rotation at a higher rotation speed R2 for a predetermined time to shake off the surplus photoresist solution R (excess photoresist solution R _d ) covering the entire surface of the substrate W. Then, a photoresist film R ′ having a desired film thickness can be formed (FIG. 4G).

The time t _E ′ at which the discharge of the photoresist solution R is stopped can be made shorter than the discharge stop time t _E of the photoresist solution R in the conventional example, as is apparent from FIG. As a result, it is possible to reduce the time required for the photoresist liquid coating process for one substrate W, and it is possible to improve the throughput when performing the photoresist liquid coating process on the substrates W sequentially.

Further, the time t _E 'when the discharge of the photoresist solution R is stopped is measured by actually discharging the photoresist solution R onto the substrate W and covering the entire surface of the substrate W with the photoresist solution R. However, it is set based on this result. Then, the time from the ejection start time t _S of the photoresist liquid R is stored in the memory 51 or set in a timer or the like, and the ejection is stopped after the time from the ejection start.

As described above, by supplying the photoresist liquid to the surface of the substrate W through the ejection holes 47 having an octagonal horizontal cross-sectional shape, the beards R _{e having a} wide width from each vertex.
And a wide beard R _e that extends while being bent in the circumferential direction and a beard R _a that linearly extends to the peripheral edge of the substrate W rapidly interact with the gap not covered by the photoresist solution. Can be narrowed. Therefore, the time from the arrival of the integrated wide beard R _e and the beard R _a to the peripheral portion of the substrate W until the supply of the photoresist liquid R is stopped is shortened. _e and mustache R
It is possible to reduce the amount of the photoresist liquid R discharged and scattered around the substrate W through _a and. As a result, the amount of photoresist liquid supplied to obtain a photoresist film having a desired film thickness can be extremely reduced.

The horizontal cross-sectional shape of the discharge hole 47 of the nozzle portion 41 is, as shown in FIG. 6, formed by forming a recess 47a in each portion of the circular outer peripheral portion corresponding to each vertex of the octagon. The radial discharge holes 47 may be used. In addition, as shown in FIG. 7, the portion corresponding to each side of the octagon is provided with a discharge hole 4
A star-shaped discharge hole 47 may be formed so as to project in an arc shape toward the central portion of 7.

Further, the horizontal cross-sectional shape of the discharge hole 47 of the nozzle portion 41 may be a pentagonal discharge hole 47 as shown in FIG. 8 (a). Further, as shown in FIG.
Recesses 47a are formed in the portions corresponding to the vertices of the pentagon, respectively.
May be formed as a radial discharge hole 47, and further,
As shown in FIG. 7C, the portion corresponding to each side of the pentagon may be a star-shaped ejection hole 47 that is formed to project in an arc shape toward the center.

Since the photoresist liquid dropped on the surface of the substrate has a radial shape from the central portion and extends toward the peripheral portion of the substrate due to the centrifugal force, the intervals of the large number of wide beards R _e are almost equal. In order to make the discharge holes 47 uniform, the horizontal cross-sectional shape of the discharge holes 47 described above is a portion where the distance from the center is long, that is, a portion where a wide beard R _e is generated (FIG.
Then, it is preferable to form each vertex portion uniformly in the circumferential direction. That is, the horizontal cross-sectional shape of the discharge hole 47 described above is preferably a regular octagon (regular pentagon) among octagons (pentagon). By doing so, the interaction between the wide beard R _e and the beard R _b is preferably performed. However, in a rectangular substrate such as a glass substrate for a liquid crystal display device, since the distance from the center of rotation to the outer edge is not uniform, the portions that cause wide beards R _e are formed at unequal intervals in the circumferential direction. You may do it.

The horizontal cross-sectional shape of the discharge hole 47 is not limited to the above-mentioned (regular) pentagon and (regular) octagon, and
For example, it may be a (regular) hexagon or a (regular) heptagon,
Further, it may have a cross shape (+ shape) or an elliptical intersection shape in which two elliptical shapes are crossed. That is, when the photoresist liquid is supplied to the substrate surface, at least 2
Various shapes can be adopted as long as they are non-circular discharge holes that can obtain various types of turning radii. However,
The horizontal cross-sectional shape of a triangle or a quadrangle has a small number of vertices and a small number of wide beards, so the effect of shortening the time for narrowing the gap of the photoresist solution is small, and a polygon exceeding an octagon has a conventional shape. It is not preferable because it is close to a circular shape and it is difficult to obtain the effect of a wide beard.

The control of the rotation speed of the substrate W may be performed as shown in FIG. That is, the substrate W is rotated at the rotation speed R3.
(E.g., 1,500 rpm) and the rotary drive, in the discharge start time t _s begins discharging a photoresist solution R, until the discharge stop time t _E ", higher rotational speed than the rotational frequency R3 R4 (e.g., (3,000 rpm). When increasing the rotation speed from R3 to R4, it should be completed in a short time (for example, 0.07 seconds). By rapidly increasing the rotation speed, the wide beard R _e and the beard R _b receive a strong inertial force in the circumferential direction, and they can spread in the circumferential direction faster than they extend to the peripheral portion of the substrate W. Therefore, the gap can be narrowed rapidly, and the coating time can be further shortened.

In the above-mentioned embodiments, the photoresist liquid is used as an example of the coating liquid for explanation, but the present invention is not limited to this.
The present invention is not limited to this, and can be applied to, for example, an apparatus for applying a coating liquid (for example, polyimide) for forming a passivation film used as a surface protection or an insulating film. Further, it can be applied to a developing solution for developing the coating film after exposure and an apparatus for supplying a rinsing solution for stopping the developing action to the substrate surface.

[0051]

As is apparent from the above description, according to the invention described in claim 1, the coating liquid can be dripped in the vicinity of the rotation center of the substrate in a non-circular shape, and the rotation radius is long. A wide beard can be extended from the portion toward the periphery of the substrate. Furthermore, since this wide beard is bent in the circumferential direction and extends, the interaction with the beard that linearly extends from between them toward the peripheral edge of the substrate rapidly narrows the gap not covered with the coating liquid. be able to. Therefore, the time required for the coating liquid to cover the entire surface of the substrate can be shortened. As a result, the amount of the coating liquid scattered around the substrate through the beard can be reduced, and the amount of the coating liquid required to obtain a coating film having a desired film thickness can be reduced. This makes it possible to reduce the amount of expensive coating liquid as compared with a processing liquid containing an organic solvent as a main component such as a developing liquid or a rinsing liquid. Can be improved.

According to the second aspect of the present invention, the same operation and the same effect as those of the first aspect are achieved.

According to the third aspect of the present invention, since wide beards can be extended from each vertex of the polygonal shape toward the peripheral edge of the substrate, the gap between them can be sharply narrowed by their interaction. It is possible to shorten the time until the coating liquid covers the entire surface of the substrate. Therefore,
The time until the coating liquid covers the entire surface of the substrate can be shortened. As a result, the amount of the coating liquid scattered around the substrate through the beard can be reduced, and the amount of the coating liquid required to obtain a coating film having a desired film thickness can be reduced.

Further, according to the invention described in claim 4, by forming the horizontal cross-sectional shape of the coating liquid supply nozzle into an octagonal shape, the interaction with the whiskers can be favorably maintained while maintaining the characteristics of the wide beard. Can be generated. As a result, the time required for coating can be shortened, and the amount of the coating liquid scattered from the peripheral portion of the substrate through the beard is reduced, so that the amount of the coating liquid required to obtain a coating film with a desired film thickness is reduced. can do.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a rotary substrate coating apparatus according to an embodiment.

FIG. 2 is a vertical cross-sectional view of a coating liquid supply nozzle and a nozzle portion.

FIG. 3 is a plan view showing discharge holes of a nozzle portion.

FIG. 4 is a schematic diagram showing the behavior of a photoresist solution on the substrate surface.

FIG. 5 is a schematic view showing the behavior of the photoresist liquid on the substrate surface.

FIG. 6 is a plan view showing a modified example of a discharge hole of a nozzle portion.

FIG. 7 is a plan view showing a modified example of discharge holes of a nozzle portion.

FIG. 8 is a plan view showing a modified example of the discharge holes of the nozzle portion.

FIG. 9 is a time chart showing a modified example of the rotation speed control.

FIG. 10 is a diagram showing a main part of a rotary substrate coating apparatus according to a conventional example.

FIG. 11 is a time chart showing a coating liquid coating method according to a conventional example.

FIG. 12 is a diagram for explaining application of a coating liquid according to a conventional example.

[Explanation of symbols]

10 ... Suction spin chuck 40 ... Coating liquid supply nozzle 41 ... Nozzle part 47 ... Discharge hole 50 ... Control part 51 ... Memory W ... Substrate R ... Photoresist liquid (coating liquid) _Ra ... Core _Rb ... Beard _Rc ... Scattered photoresist solution R _d … Excess photoresist solution R _e … Wide beard

Claims (4)

[Claims] 1. A substrate is rotated at low speed by a rotation supporting means at a predetermined rotation speed, and a coating liquid is supplied to the vicinity of its rotation center through a coating liquid supply nozzle, and then the rotation speed is kept at a predetermined rotation speed. In a rotary substrate coating apparatus that forms a coating film having a predetermined film thickness on a substrate surface by rotating at high speed, at least the discharge hole of the coating liquid supply nozzle is formed in a non-circular shape in its horizontal cross-sectional shape. A rotary type substrate coating device characterized by: 2. A substrate is rotated at low speed by a rotation supporting means at a predetermined rotation speed, and a coating liquid is supplied to the vicinity of the center of rotation through a coating liquid supply nozzle, and then the rotation speed is kept at a predetermined rotation speed. In a rotary substrate coating apparatus that forms a coating film having a predetermined film thickness on a substrate surface by rotating at high speed, at least the outer shape of the lower surface of the coating liquid supply nozzle is formed in a non-circular shape in horizontal cross section. A rotary type substrate coating device characterized by: 3. The rotary substrate coating apparatus according to claim 1 or 2, wherein the horizontal sectional shape is a polygon. 4. The rotary substrate coating apparatus according to claim 1 or 2, wherein the horizontal cross-sectional shape is an octagon.