JP2003211049A - Liquid coater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid coater capable of providing a coating film of uniform film thickness with less dispersion (coating irregularities) of the film thickness to the end part of the coating film. <P>SOLUTION: In a coating head 20 provided with a slot 27 for making a liquid flow out in fixed thickness, both wall surfaces facing each other of the tip opening part 28 of the slot 27 are formed as slopes 21c and 22c inclined mutually in the opposite directions, the slopes 21c and 22c are made of a hydrophilic surface material and the lower end face of the coating head 20 continued on the outer side of the slopes 21c and 22c is made of a water repellent surface material. On either one or both of the wall surfaces facing each other of the tip opening part 28 of the slot 27, a linear scar in the width direction of the coating head 20 is formed. The slopes 21c and 22c can be constituted of convex or concave curved surfaces, respectively. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention of the present application relates to a slot type liquid coating apparatus for coating a surface of a substrate such as a semiconductor substrate or a liquid crystal substrate with a uniform film thickness, and particularly to a film at the end of the coating film. The present invention relates to a liquid application device that prevents an increase in thickness and improves film thickness uniformity.

[0002]

2. Description of the Related Art Variations in the thickness of a coating film such as a resist solution or a chromium coating solution applied to a substrate such as a semiconductor substrate or a liquid crystal substrate (uneven coating) are directly related to variations in the wiring width.
In the past, a spin coater was used to obtain a uniform film thickness with little variation, but this spin coater
There is a problem that a large amount of coating liquid is consumed.

On the other hand, a slot coater (curtain coater,
The use of a slot-type liquid coating device such as a die coater requires a small amount of coating liquid and is low in cost, but there is a large variation in film thickness, and the problem of uniform film thickness remains. In particular, the variation in the film thickness at the beginning of coating is so-called line drawing, which is dragged not only at the beginning of coating but also over the entire area, which affects the variation in the film thickness in the entire region of the substrate.

As a means for improving the condition at the beginning of coating and for making the film thickness uniform, it is the first to make the gaps of the slots uniform over the entire width of the coating head, and for that purpose various Though some efforts have been made, some problems still remain. For example, the gap between the tip openings (nozzle openings) of the slots is several tens of microns, and there is a limit to mechanically polishing the inner wall surface of the openings with a surface accuracy of several microns or less. As for the assembly accuracy of the parts that affect the accuracy of the width of the opening, there is a problem of how to improve the assembly accuracy by combining the parts of the coating head (slot nozzle). Was also precise.

Further, in general, when the coating liquid is supplied to the coating head to flow out from the tip opening portion of the slot, as shown in FIG. 8A, before the coating is started, the tip opening of the slot 027 is shown. Liquid sagging occurs in the portion 028, and this liquid sagging is caused by a plurality of liquid balls in the width direction (length direction) of the coating head 020.
029 is in the created state. As a result, in the range of about 5 to 10 mm at the beginning of coating, line drawing is performed as shown by the dark dot pattern in FIG.
The film thickness distribution at the position A has a shape as shown in the sectional view taken along the line AA of FIG. 8C, and there is a considerable variation in the film thickness. Further, even at the BB position which is a position other than the start of coating, as shown in the BB sectional view of FIG. 8C, some variation in film thickness remains. This is because the line drawing at the beginning of painting affects the rest.

As an example of a past patent application, for example, in the one disclosed in Japanese Patent Application Laid-Open No. 11-57533, many particles are formed on the wall surface of the tip opening on the side where the liquid flows out of the slot in order to make the liquid ball as small as possible. It has been attempted to provide a wire in the width direction directly below the tip opening portion of the slot so that a fine vertical groove (streak mark) is provided or the liquid droplet itself is not generated.

However, in spite of these attempts, according to the conventional method, it is possible to obtain a coating film having a uniform film thickness with little variation (coating unevenness) in the coating film even over the end portion of the coating film. Therefore, a slot-type liquid application device that can withstand practical use has not yet been obtained.

[0008]

SUMMARY OF THE INVENTION The invention of the present application solves the above-mentioned problems of the conventional slot type liquid coating device, and the variation in the film thickness (coating unevenness) is extended to the end of the coating film. It is an object of the present invention to provide a liquid coating apparatus of this kind that can obtain a coating film having a uniform thickness with less amount of).

[0009]

The invention of the present application relates to a liquid coating apparatus which solves the above problems,
In the invention described in claim 1, a liquid injection port for injecting a liquid, a cavity for diffusing the liquid injected from the liquid injection port in the width direction, and a liquid in the cavity are kept constant. In a liquid application device having a slot for allowing the liquid to flow out and having a slot for discharging, a space sandwiched between the two wall surfaces facing each other at the tip opening of the slot gradually expands in the liquid discharge direction. As described above, the inclined surfaces are inclined in opposite directions, and the inclined surface is
The lower end surface of the coating head, which is made of a hydrophilic surface material and extends outward from the inclined surface, is made of a water-repellent surface material, and the boundary between the hydrophilic surface material and the water-repellent surface material is The liquid coating apparatus is formed along the width direction of the coating head.

Since the invention described in claim 1 is configured as described above, the following effects can be obtained. Both wall surfaces of the tip opening (nozzle port) of the slot provided in the coating head are opposed to each other so that the space sandwiched between these wall surfaces gradually expands in the liquid ejection direction. There is an inclined surface between the vertical portions of the opposite wall surfaces of the slot to the portion where the lower edges of these wall surfaces are connected to the lower end surface of the coating head. Similarly, the direction of the contact angle with respect to the wall surface of the part changes in three steps. As a result, the stability of the liquid when the coating liquid is discharged is improved, liquid droplets are less likely to form, and unevenness of the film thickness of the coating film in the width direction of the coating head is reduced.

Further, by forming the inclined surface as described above, the space portion which is gradually sandwiched between the inclined surfaces and which gradually expands in the ejection direction of the liquid provides a place for preparation for forming a bead. The bead can be generated only when there is the space portion, and the bead thus generated is buried in the concave portion of the space portion so that the shape is stably maintained. Further, the inclined surface is made of a hydrophilic surface material, and the lower end surface of the coating head connected to the outer side of the inclined surface is made of a water repellent surface material. Since the boundary with the material is formed along the width direction of the coating head, when the bead is formed and the forefront line where the discharge liquid surface contacts the tip opening of the slot exceeds the boundary, the bead formation Therefore, the discharge liquid surface rises and the contact angle of the discharge liquid with respect to the wall surface of the opening sharply increases, but a steep rise is avoided because of the inclined surface on the inside, and the outside water-repellent surface material makes it outward. The protrusion of the bead is also prevented, and the stability of the bead is obtained when the bead is formed. By these, the generation of liquid drops is more effectively suppressed, and the nonuniformity of the film thickness of the coating film in the width direction of the coating head is further reduced.

In this way, the bead formation during the discharge of the coating liquid is doubled or tripled, the stability is obtained, the shape of the formed bead is stably maintained, and the generation of the liquid beads is effectively suppressed. Therefore, the stability of the coating liquid is greatly improved, the nonuniformity of the coating film thickness in the width direction of the coating head is greatly reduced, and the variation in the coating thickness at the beginning of coating is extremely small. At positions other than the beginning, it becomes smaller, and the uniformity of the film thickness is remarkably improved even over the end portion of the coating film. In addition, the stability of the coating solution is greatly improved, which facilitates control of the film thickness.

By constructing the invention according to claim 1 as described in claim 2, one or both of the opposing wall surfaces of the tip opening portion of the slot is provided with the coating head. Striation marks extending in the width direction are formed.

As a result, the discharge liquid existing in the space expansion portion (liquid pool portion) of the tip opening portion (nozzle port) of the slot is
A wider contact area is obtained with the wall of the tip opening, so that the liquid is more strongly retained by this wall. As a result, more stability is obtained in the generation of beads, the shape of the generated beads is held more stably, the generation of liquid beads is suppressed more effectively, and the stability of the coating liquid is further improved. The above-described effects of the invention according to claim 1 are further promoted.

Further, as described in claim 3, claim 1
Alternatively, according to the invention of claim 2, the inclined surface is formed by a convex or concave curved surface.

As a result, if the shape of the inclined surface is selected to be uneven so that the beads can be stably formed depending on the type of the coating liquid, the direction of the metal surface of the tip opening (nozzle port) of the slot is gradually and continuously. Since it changes, the direction of the contact angle of the coating liquid surface with respect to the metal surface also changes continuously, and a better bead can be formed, and the generation of liquid beads can be suppressed even more effectively. Since the stability of the liquid is further improved, the above-described effects of the invention according to claim 1 or 2 are further promoted.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment (Embodiment 1) of the invention described in claim 1 of the present application shown in FIGS. 1 to 5 will be described. 1 is a schematic perspective view of a liquid coating apparatus according to the first embodiment, FIG. 2 is a cross-sectional view of a coating head used in the liquid coating apparatus, FIG. 3 is an exploded perspective view of the coating head, and FIG. FIG. 4A is a diagram showing an application head filled with the application liquid and the application state of the application liquid by the application head. FIG. The figure which shows the state where a bead is formed, (b) is a top view of the board | substrate which shows the coating state of the applied coating liquid, (c) is the coating liquid of the AA and BB position of (b). Sectional view of the substrate showing the situation, FIG.
FIG. 7 is a diagram showing a process in which a bead is formed at an opening portion of a slot end of the coating head in comparison with a conventional example.

The liquid coating apparatus according to the first embodiment is a liquid or liquid material (hereinafter, referred to as a resist liquid, a chromium coating liquid, etc.) having a uniform film thickness on the surface of a substrate such as a semiconductor substrate or a liquid crystal substrate.
These are collectively referred to as "coating liquid" or "liquid". ) Is used for coating. The overall structure is
Schematically, as shown in FIG. 1, a table 3 is installed near a central portion on a base 2 which is a base of the liquid application apparatus 1, and a substrate 4 which is an application object is provided on an upper surface of the table 3.
Is placed. Side walls 2a and 2b which are erected at right angles are formed on both side edges of the base 2, and rails 5a and 5b are laid on the upper surfaces of the side walls 2a and 2b and guides are provided on these rails 5a and 5b. While the coating mechanism unit 10 is running, the coating liquid ejected from the lower end nozzle portion of the coating head 20 that is vertically movable in the coating mechanism unit 10 travels with the coating mechanism unit 10 and the coating head 20. The coating film is applied on the substrate 4 with a uniform film thickness from the coating start end to the coating end.

The lower end nozzle portion of the coating head 20 is an elongated nozzle portion having a length exceeding the width of the substrate 4 (the length of the substrate 4 in the direction orthogonal to the running direction of the coating head 20). The coating liquid is uniformly discharged from the.
The structure of the coating head 20 will be described in detail later.

The coating mechanism section 10 includes a pair of left and right moving bases 11a,
11b, a head holding frame 12 is bridged between the moving bases 11a and 11b so as to be able to move up and down, and the coating head 20 is attached to the head holding frame 12. Therefore, the coating head 20 is the head holding frame.
As the head 12 moves up and down, it moves up and down integrally with the head holding frame 12. The head holding frame 12 is a movable table.
The lifting cylinders 13a and 13b are fixed to the lifting and lowering cylinders 11a and 11b, and the lifting and lowering cylinders 13a and 13b move up and down.

Linear drive parts 14a and 14b are attached to the lower parts of the movable tables 11a and 11b (linear drive part 14a).
Is not shown). Electric power is supplied to the linear drive units 14a and 14b by a movable cable 15. Therefore,
Now move the movable cable 15 to these linear drives 14a and 14b.
Powered by, though not shown in detail,
Electromagnets excited by electromagnetic coils provided in the linear drive parts 14a, 14b and permanent magnets 16 laid on the upper surfaces of both side walls 2a, 2b of the base 2 in parallel with the rails 5a, 5b.
Suction and repulsion occur between a and 16b, and the moving table 11a
, 11b are generated, and the moving bases 11a, 11b start traveling in either the front or back direction according to the direction of the exciting current while being guided by the rails 5a, 5b. Mobile stand 11
Linear bushes 17a and 17b are fixed to the lower surfaces of a and 11b. The linear bushes 17a and 17b are fitted on the rails 5a and 5b and slide, so that the movable bases 11a and 11b move to the rail 5a. Drive while being guided by 5b.

Although not shown in detail in the front part (lower left in FIG. 1) of the table 3 on the base 2, maintenance work such as replacement of the coating head 20 and cleaning of the lower end nozzle portion of the coating head 20 is performed. A maintenance mechanism unit 18 used when performing is installed.

Next, the structure of the coating head 20 will be described in detail. As shown in FIGS. 2 and 3, the coating head 20 is composed of two divided heads 21, 22 and a shim 23. And a shim between these two split heads 21, 22
It is formed by sandwiching 23. Each of the two divided heads 21 and 22 is made of a metal (stainless steel) block having an elongated rectangular parallelepiped shape, and tooth tips 21a and 22a protruding in an acute angle are provided at lower portions of the sides facing each other.
Are formed. The lower end surfaces of the two divided heads 21 and 22 surrounding the addendum portions 21a 1 and 22a 2 are formed in a horizontal plane.

As shown in FIG. 3, the shim 23 is made of a thin plate punched out in a U-shape, and the U-shaped recess 23a has a shim 23 between the two divided heads 21 and 22. When sandwiched, it forms a slot 27 between these two split heads 21,22. The thickness of the shim 23 is this slot
Determine the size of the gap of 27.

A liquid injection port 24 for injecting a liquid forming a coating liquid is formed at the center of the lengthwise direction (widthwise direction of the coating head 20) on the upper part of one of the divided heads 21 and its length. Air vents 34 are formed near both ends in the vertical direction. Similarly, a hollow portion 26 for diffusing the liquid injected from the liquid injection port 24 in the width direction is formed in the middle portion of one of the divided heads 21. Then, three through holes 25 for communicating the liquid injection port 24 and the cavity 26 are formed. The hollow portion 26 communicates with the slot 27, and the liquid in the hollow portion 26 is made to have a constant thickness by the slot 27 and is discharged from the tip opening portion 28 below the slot 27. The tip opening portion 28 of the slot 27 forms a nozzle opening of the lower end nozzle portion of the coating head 20.

The opposite wall surfaces of the tip opening portion (nozzle port) 28 of the slot 27 are inclined surfaces 21c and 22c which are inclined in mutually opposite directions so that the space between these wall surfaces gradually expands in the liquid ejection direction. Has been done.

Tip portion of the lower part of the two split heads 21, 22
The outer surfaces of 21a and 22a are inclined surfaces 21b which are inclined in opposite directions so as to gradually approach in the downward direction (liquid ejection direction).
, 22b. And these slopes 21b, 2
2b is coated with Teflon (registered trademark). The inner side surfaces of the tooth top portions 21a 1 and 22a 2 form a part of the wall surface of the slot 27, and the lower edge vicinity portions including the lower edge thereof are the inclined surfaces 21c and 22c.

Therefore, the inclined surface 21b and the inclined surface 21c form inclined surfaces which are inclined in opposite directions so as to gradually approach each other in the downward direction, and their lower edges are adjacent to each other through the elongated strip-shaped horizontal plane portion 21d. Matching. Also, the inclined surface 22b
And the inclined surface 22c are inclined surfaces that are inclined in opposite directions so as to gradually approach each other in the downward direction, and their lower edges are adjacent to each other via an elongated strip-shaped horizontal surface portion 22d. Although these elongated strip-shaped horizontal plane portions 21d and 22d are always left in the processing, the lower end nozzle portion of the coating head 20 prevents the substrate 4 from being damaged and stabilizes the bead 30 of the discharge liquid described later. Help to generate.

However, the inclined surfaces 21b and 22b do not necessarily have to be inclined surfaces, and may be horizontal surfaces following the elongated strip-shaped horizontal surface portions 21d and 22d (the inclined surface 21c.
, 22c remains. ). In this case, the entire lower end surfaces of the two divided heads 21 and 22 are flat surfaces, and
21a and 22a are eliminated. However, even in this case,
A Teflon coating is applied to the entire flat lower end surface or a required area near the lower edges of the inclined surfaces 21c and 22c.

The tooth tip portions 21a of the two split heads 21 and 22,
22a inclined surfaces 21b, 22b or two split heads 21,
The Teflon coating is applied to the required area of the 22 flat lower end surfaces for the following reasons. As described above, the basic material of the coating head 20 is stainless steel, the contact angle (θ) of the liquid with respect to this material is about 10 degrees, and it is hydrophilic. On the other hand, the contact angle of the coating liquid with respect to the Teflon coated on the inclined surfaces 21b and 22b is about 60 degrees, which means that it is water repellent. Therefore, the inside of the tip opening 28 of the slot 27 is made of stainless steel and the outside is made of Teflon, which is a boundary between two materials having opposite properties, and the liquid is made constant in thickness by the slot 27 and the tip opening is made. When the liquid is discharged from the portion 28, the liquid tries to permeate around the tip opening 28, but the liquid is inclined 21
When b and 22b are reached, the liquid surface rises at the horizontal plane portions 21d and 22d that form the boundary between stainless steel and Teflon (see FIG. 5, (invention) (d)), and the liquid overflows outside. Disturbed.

Next, the operation of the liquid coating apparatus 1 according to the first embodiment will be described. At the start of liquid application to the substrate 4, the application head 20 is set at a predetermined height position at the front end (lower left end in FIG. 1) of the substrate 4. In this state, when a liquid (coating liquid) is supplied to the coating head 20 from a liquid supply source (not shown), the liquid is guided from the liquid inlet 24 through the through hole 25 to the cavity 26, and then the slot. 27 to a certain thickness, slot 27
Is discharged from the tip opening portion 28 below. At the same time, the linear driving units 14a and 14b are activated and the coating mechanism unit 10 starts running. As a result, the coating head 20 has a tip opening portion.
The coating liquid ejected from the substrate 28 is applied to the substrate 4 evenly from the coating start end to the coating end with a uniform film thickness while moving toward the rear end (upper right end in FIG. 1) of the substrate 4. Run.

The liquid coating apparatus 1 according to the first embodiment is
Since it is configured as described above, the following actions and effects can be obtained. Both opposing wall surfaces of the tip end opening portion 28 of the slot 27 of the coating head 20 are inclined surfaces 21c and 22c which are inclined in mutually opposite directions so that the space sandwiched by these both wall surfaces gradually expands in the liquid ejection direction. Therefore, as shown in FIG. 4 (a), the size of the liquid ball 29 becomes smaller than that of the conventional one (see FIG. 8), and The number of beads is reduced, and moreover, uniform beads 30 can be formed along the width direction of the tip opening 28.

As a result, the distribution of the film thickness of the coating film on the substrate 4 is as shown in the cross section AA of FIG. 4C, at the beginning of coating (position AA in FIG. 4B). The variation in the film thickness at the time is much smaller than before, and B in FIG. 4 (c)
As shown in the -B cross-sectional view, it can be seen that it becomes smaller at positions other than the start of coating (position BB in FIG. 4B), and the uniformity of the film thickness is improved.

The reason why such a result is obtained will be described in detail below with reference to FIG. FIG. 5 is a diagram showing the state of ejection of the coating liquid by the coating head 20 of the first embodiment and the state of ejection of the coating liquid by the conventional coating head 020 for comparison. As is clear from this figure, in the conventional coating head 020, the tip of the liquid is the tip opening.
When reaching 028, the orientation of the metal surface in contact with the liquid is displaced from the vertical direction (see (conventional) (a) and (b)) to the horizontal direction (see (conventional) (c)). The contact angle of the liquid with respect to the metal surface is about 10 degrees in the case of stainless steel, but it changes similarly while maintaining that angle. Due to such a sudden change in the liquid level, the state of the liquid becomes very unstable, and liquid balls 029 are generated at various places ((conventional) (see (d)), and the liquid is discharged in this state ( (Conventional)
(See (e)), it is impossible to avoid the occurrence of non-negligible nonuniformity of the film thickness of the coating film in the width direction of the coating head 020.

On the other hand, the coating head of the first embodiment
In the case of 20, the opposite wall surfaces of the tip opening 28 of the coating head 20 are inclined surfaces 21c and 22c, so that the direction of the metal surface in contact with the liquid is the vertical direction ((the present invention) (a)).
(See (present invention) (c)), the inclined surfaces 21c and 22c are interposed (see (present invention) (b)), and the direction of the contact angle of the discharge liquid surface Also changes in three steps. As a result, the stability of the liquid when discharging the coating liquid is improved, and it becomes difficult to form the liquid ball 29,
Since the liquid is discharged in this state (see (Embodiment) (e)), the occurrence of non-uniformity of the film thickness of the coating film in the width direction of the coating head 20 is reduced.

Further, by forming the inclined surfaces 21c and 22c as described above, the space portion which is sandwiched between the inclined surfaces 21c and 22c and which gradually expands in the discharge direction of the liquid is the bead 30.
This provides a place for preparation for forming the beads, and the beads 30 can be produced only by the presence of this space portion (see (the present invention) (d)). And once the bead 30 is formed in this space part, this end expansive space part is very effective in maintaining the shape of that bead 30, and the bead 30 has the shape of this end expanse space part. The shape of the bead 30 is very stable because the two inclined surfaces 21c and 22c that form the space portion with the optimum fit hold the shape of the completed bead 30 by the holding force. Moreover, since the completed bead 30 is buried in the concave portion of this space, the portion exposed from the tip opening portion 28 can be minimized, and in the conventional case, the portion exposed from the tip opening portion 028 is small. Since it is large ((conventional) (see (d)), the distortion of the liquid surface causes instability of the hydraulic pressure in the width direction, but this is not the case. From this aspect as well, it is possible to effectively suppress the generation of the liquid drops 29.

Furthermore, the inclined surfaces 21c and 22c are made of a hydrophilic surface material, and the inclined surfaces of the tip portions 21a and 22a of the lower end of the coating head 20 connected to the outside of the inclined surfaces 21c and 22c.
21b and 22b are made to have a water-repellent surface material, and the boundary between the hydrophilic surface material and the water-repellent surface material is the coating head 20.
Since it is formed along the width direction of the bead 30, when the bead 30 is formed and the forefront line where the discharge liquid surface comes into contact with the tip opening 28 of the slot 27 exceeds the boundary, discharge is performed for forming the bead 30. Although the liquid surface rises and the contact angle of the discharge liquid with the wall surface of the opening increases sharply, a steep rise is avoided because of the inclined surfaces 21c and 22c on the inside, and the outer water-repellent surface material prevents the liquid from rising outward. The protrusion of the bead 30 is also prevented, and the stability of the bead 30 is obtained even when the bead 30 is formed. As a result, the generation of the liquid drops 29 is more effectively suppressed.

As described above, in the coating head 20 according to the first embodiment, the beads at the time of discharging the coating liquid are doubled or tripled.
The stability of the production of the beads 30 is obtained, the shape of the produced beads 30 is stably held, and the generation of the liquid beads 29 is effectively suppressed, so that the stability of the coating liquid is greatly improved and the coating is performed. head
The non-uniformity of the film thickness of the coating film in the width direction of 20 is greatly reduced, and the variation in the film thickness at the beginning of coating is extremely small,
Further, at a position other than the start of coating, the size becomes smaller, and the uniformity of the film thickness is remarkably improved even over the end portion of the coating film.
In addition, the stability of the coating solution is greatly improved, which facilitates control of the film thickness.

Next, an embodiment (second embodiment) of the invention described in claim 2 of the present application shown in FIG. 6 will be described. FIG. 6 is a diagram showing a state in which line marks are formed on the wall surface of the slot tip opening of the coating head used in the liquid coating apparatus according to the second embodiment. The same parts as those of the coating head 20 used in the liquid coating apparatus 1 according to the first embodiment are designated by the same reference numerals.

In the coating head 20 used in the liquid coating apparatus 1 according to the second embodiment, the front end opening (nozzle port) 28 of the slot 27 has an inclined surface that forms both opposing wall surfaces.
21c, 22c), a plurality of linear scratches 31 extending in the width direction of the coating head 20 and extending over substantially the entire width of the coating head 20 are formed on either or both of them. There is. The liquid application device 1 of the second embodiment is different from the first embodiment in the above points, but is not different in other points, and thus detailed description thereof will be omitted.

Since the liquid applicator 1 of the second embodiment is configured as described above, the liquid pool portion of the tip end opening portion 28 has a wider contact area with the nozzle material portion, and the liquid is formed by the metal portion. It will be held more strongly, the bead 30 will be generated more stably, the shape of the bead 30 generated will also be held more stably, and the generation of liquid beads 29 will be suppressed even more effectively, and the coating liquid Stability is further improved. Thereby, the uniformity of the film thickness even over the end portion of the coating film is further improved.

Next, an embodiment (third embodiment) of the invention described in claim 3 of the present application shown in FIG. 7 will be described. FIG. 7 is a diagram showing a state in which curved surfaces having different shapes are formed on both opposing wall surfaces of the slot tip opening of the coating head used in the liquid coating apparatus according to the third embodiment, and FIG. A diagram showing a state in which a curved surface is formed,
(B) is a figure which shows the state in which the concave curved surface was formed. The same parts as those of the coating head 20 used in the liquid coating apparatus 1 according to the first embodiment are designated by the same reference numerals.

In the coating head 20 used in the liquid coating apparatus 1 according to the third embodiment, the tip end opening portion (nozzle port) 28 of the slot 27 has inclined surfaces forming opposite wall surfaces.
21c and 22c are composed of convex and concave curved surfaces 32 and 33. Which of the convex curved surface 32 and the concave curved surface 33 is selected depends on the type of the coating liquid, and the bead 30 with which surface is more stable.
It may be determined depending on whether it helps to form The liquid application device 1 of the third embodiment is different from the first embodiment in the above points, but is not different in other points, and thus detailed description thereof will be omitted.

Since the liquid coating apparatus 1 of the third embodiment is configured as described above, the shape of the inclined surface is selected to be uneven so that the bead 30 can be stably formed depending on the type of coating liquid. If so, the direction of the metal surface will gradually and continuously change, the direction of the contact angle of the coating liquid with respect to the metal surface will also continuously change, it is possible to form a better bead 30. Further, the generation of the liquid beads 29 is suppressed more effectively, and the stability of the coating liquid is further improved.
Thereby, the uniformity of the film thickness even over the end portion of the coating film is further improved.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a liquid application apparatus according to an embodiment (Embodiment 1) of the invention described in claim 1 of the present application.

FIG. 2 is a cross-sectional view of a coating head used in the liquid coating apparatus.

FIG. 3 is an exploded perspective view of the coating head.

FIG. 4 is a view showing the same coating head filled with a coating liquid and a coating state of the coating liquid by the coating head,
FIG. 3A is a diagram showing a state in which a liquid ball and a bead are formed in a slot end opening of a coating head filled with a coating liquid;
(B) is a plan view of the substrate showing the coating state of the applied coating liquid, and (c) is a sectional view of the substrate showing the coating state of the coating liquid at the positions AA and BB in (b).

FIG. 5 is a diagram showing a process in which a bead is formed in an opening portion of a slot end of the coating head in comparison with a conventional example.

FIG. 6 shows a state in which a linear mark is formed on a wall surface of a slot tip opening portion of a coating head used in a liquid coating apparatus according to an embodiment (second embodiment) of the invention described in claim 2 of the present application. FIG.

FIG. 7 is a view showing that curved surfaces having different shapes are formed on opposite wall surfaces of a slot end opening of a coating head used in a liquid coating apparatus according to an embodiment (third embodiment) of the invention described in claim 3 of the present application. It is a figure which shows the state which was carried out, (a)
FIG. 4A is a diagram showing a state in which a convex curved surface is formed, and FIG. 6B is a diagram showing a state in which a concave curved surface is formed.

FIG. 8 is a diagram showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquid coating device, 2 ... Base, 2a, 2b ... Base side wall, 3 ... Table, 4 ... Substrate, 5a, 5b ... Rail, 10
... Coating mechanism section, 11a, 11b ... Moving table, 12 ... Head holding frame, 13a, 13b ... Lifting cylinder, 14a, 14b ... Linear drive section, 15 ... Movable cable, 16a, 16b ... Permanent magnet,
17a, 17b ... Linear bushing, 18 ... Maintenance mechanism,
20 ... Coating head, 21 ... Split head, 21a ... Tooth tip, 21b
… Sloping surface, 21c… Sloping surface, 21d… Band-shaped horizontal plane part, 22
... Split head, 22a ... Tooth tip, 22b ... Sloping surface, 22c ... Sloping surface, 22d ... Strip-shaped horizontal plane portion, 23 ... Shim, 23a ... Recessed portion, 24 ... Liquid injection port, 25 ... Through hole, 26 ... Cavity portion , 27 ... slot, 28 ... tip opening (nozzle), 29 ... liquid bead, 30 ... bead, 31 ... line mark, 32 ... convex curved surface, 33 ... concave curved surface, 34 ... air vent.

Claims (3)

[Claims] 1. A liquid injection port for injecting a liquid,
In a liquid coating apparatus comprising a coating head having a cavity for diffusing the liquid injected from the liquid inlet in the width direction and a slot for making the liquid in the cavity have a constant thickness and flowing out, The opposite wall surfaces of the front end opening of the slot are inclined surfaces that are inclined in mutually opposite directions so that the space sandwiched by the both wall surfaces gradually expands in the liquid ejection direction, and the inclined surface is a hydrophilic surface. The lower end surface of the coating head, which is made of a material and is continuous to the outside of the inclined surface, is made of a water-repellent surface material, and the boundary between the hydrophilic surface material and the water-repellent surface material is the coating head. A liquid application device formed along the width direction of the liquid application device. 2. A linear mark extending in the width direction of the coating head is formed on one or both of the opposite wall surfaces of the opening of the tip of the slot. The liquid application device according to item 1. 3. The liquid application apparatus according to claim 1, wherein the inclined surface is formed of a convex or concave curved surface.