JP2017188502A - Coating device and coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating device for enlarging an effective region of a coated substrate by improving film thickness uniformity of a coating film in a coating start part, in particular, in coating of a coating liquid to a surface of the coating object substrate of a single wafer using a slot die coater, and a coating method.SOLUTION: The coating device performs coating by discharging a coating liquid from a slot tip of a slot die while the slot die moves in one direction relative to a coated substrate. Film thickness uniformity of coating can be improved by using the coating device characterized in that multiple slot dies are installed in a direction where the slot dies move relative to the coating object substrate, and that can independently control discharge and a discharge condition of the coating liquid for each of the multiple slot dies.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a coating apparatus and a coating method for applying a coating liquid to the surface of a single substrate to be coated, for example, a coating apparatus for coating a resist on a glass substrate of a color filter for liquid crystal, and It relates to a coating method.

  As a method for forming a coating film such as a resist on a glass substrate in a color filter for a large size liquid crystal display, it is common to perform coating using a slotless coater that is a spinless system.

The slot die coater has a slot die having an elongated opening on the slit, and discharges the coating liquid from the opening of the slot die to form a bead (liquid pool) between the slot die and the substrate to be coated. A coating film is formed by moving the substrate to be coated or the slot die while discharging the coating liquid.
The formation of a coating film by a slot die coater has an advantage that the loss of coating liquid can be greatly reduced as compared with the case of a spin coater.

  As described above, in the coating by the slot die coater, a bead is formed in a state where the slot die is stopped relatively to the substrate to be coated, and the slot die is applied to the substrate to be coated while discharging the coating liquid. The coating film is formed by relatively moving them. At this time, the film thickness and film thickness uniformity of the coating film are adjusted by changing conditions such as the discharge amount of the coating liquid, the discharge pressure, the relative speed between the slot die and the substrate to be coated, and their rate of change over time. .

When the object to be coated is a single wafer such as a glass substrate, a step of forming a bead at the start of coating is required for each coating. The coating start portion for forming the bead is difficult to control the film thickness of the coating film, and the film thickness becomes unstable, which is a factor that deteriorates the film thickness uniformity.
Moreover, the effective area | region of a to-be-coated substrate is restrict | limited by this area | region where film thickness is unstable.

  In order to improve the film thickness uniformity of the coating film, the method of applying while changing the discharge amount according to the coordinates in the coating direction (Patent Document 1), the discharge pressure of the coating liquid and the relative speed of the coating head and the substrate Although a method of controlling in conjunction (Patent Document 2) has been proposed, it cannot be said that sufficient accuracy has been obtained with respect to the required accuracy, and further improvement is required.

JP 2004-148148 A JP 2002-239445 A

  When applying a coating solution to the surface of a substrate to be coated using a slot die coater, the coating film thickness uniformity at the coating start part is improved, and the effective area of the substrate to be coated is increased. An object is to provide a coating apparatus and a coating method.

That is, the invention described in claim 1 is a coating apparatus that performs coating by discharging a coating liquid from the slot tip of the slot die while the slot die moves relative to the substrate to be coated in one direction. A plurality of the slot dies are installed in a direction in which the slot die moves relative to the substrate to be coated, and the discharge of the coating liquid and the discharge conditions are controlled independently for the plurality of slot dies. It is a coating apparatus characterized by having a mechanism.

  Next, the invention according to claim 2 is the coating apparatus according to claim 1, wherein the plurality of slot dies have a mechanism that moves independently with respect to the substrate to be coated. .

  Next, the invention according to claim 3 uses the coating apparatus according to claim 1 or 2, wherein at least one slot die of the plurality of slot dies moves relative to the substrate. In the coating method, the plurality of slot dies start coating without forming a bead before starting the coating.

  According to the present invention, it is possible to expand the effective area of the substrate to be coated by reducing the film thickness variation at the coating start portion where the coating film thickness variation is large, and it is possible to effectively utilize the substrate to be coated. It becomes. Further, since the effective area of the coating film increases, the coating area necessary for obtaining a certain area of effective area on the substrate to be coated can be reduced. These effects also lead to cost reduction effects. Improvement of the film thickness uniformity of the coating makes it possible to cope with high-definition color filters.

It is the schematic of one Embodiment of the coating device of this invention. It is the schematic of one Embodiment of the coating method of this invention. It is a conceptual diagram of the film thickness of the coating film in one Embodiment of the coating method of this invention.

Embodiments of the present invention will be described below with reference to the drawings. In the following, a coating apparatus having two slot dies will be described as an embodiment, but three or more slot dies may be provided.
FIG. 1 is a schematic view of an embodiment of a coating apparatus of the present invention. A coating apparatus according to an embodiment of the present invention includes a stage 2 on which a substrate 1 to be coated 1 is placed and fixed, two slot dies 11 and 21, and a mechanism for supplying a coating liquid to each slot die. Yes.
The coating liquid supply mechanism can use a known structure and can control the start / stop of the supply of the coating liquid, the supply pressure of the coating liquid, the supply amount of the coating liquid, and their rate of change over time.

  FIG. 1 shows an example of a coating liquid supply mechanism. Storage tanks 13 and 23 for stocking the coating liquids 12 and 22 and discharge pipes for discharging the coating liquids 12 and 22 from the storage tanks 13 and 23 are shown. 14, 24, pressurizing pipes 15 and 25 for pressure-feeding the coating liquids 12 and 22 discharged from the discharge pipes 14 and 24 to the slot die, valves 16 and 26 for controlling the supply / cutoff of the coating liquid, and a filter 17 and 27 are provided.

Further, the two slot dies 11 and 21 can move relative to the substrate 1 to be coated, and the slot dies may be interlocked with each other, but they are oriented on the same straight line. Are preferably able to move independently.
Therefore, although not shown, each of the stage and the two slot dies has a driving device for movement.

  Therefore, since the two slot dies 11 and 21 can move independently with respect to the substrate to be coated and can supply the coating liquid independently, the moving speed of the slot die with respect to the substrate to be coated, Coating conditions such as the discharge pressure and discharge amount of the coating liquid, and the rate of change thereof can be set for each slot die.

  The two slot dies are installed side by side in the direction of relative movement with respect to the substrate to be coated.

  By having these structures in the coating apparatus, a plurality of slot dies can form different coating thickness distributions, and it is also possible to perform coating without overlapping time intervals. .

Next, the coating method will be described.
FIG. 2 shows a state where two slot dies 11 and 21 are coated on the substrate 1 to be coated, which is placed and fixed on the stage in the order of the slot die 11 and the slot die 12. As shown in FIG. 2A, first, the bead 18 is formed in a state where the slot die 11 is not moved with respect to the substrate 1 to be coated. Thereafter, coating is performed while the slot die 11 moves relative to the substrate 1 to be coated in the direction of the white arrow. Next, as shown in FIG. 2B, the slot die 21 starts coating without forming beads before starting to move relative to the substrate 1 to be coated. The slot die 21 overlaps the coating film 19 formed by the slot die 11 to form a coating film 29.
The start of coating by the slot die 21 may be after the coating by the slot die 11 is completed or during the coating.

  Among the plurality of slot dies, the number of slot dies that do not form a bead before starting relative movement with respect to the substrate 1 to be coated and the coating order are such that at least one slot die is relative to the substrate 1 to be coated. There is no restriction other than the condition that the bead is not formed before the relative movement.

  In the coating with each slot die, the relative movement speed of the slot die with respect to the substrate 1 to be coated and the coating conditions can be set independently, so that the film thickness distribution of the coating film can be changed for each slot die. .

  In the coating by the slot die 11, the bead 18 is formed before the relative movement with respect to the substrate 1 to be coated, so that the coating film thickness is increased at the coating start portion. On the other hand, in the coating in which the beads are not formed before the relative movement of the slot die 21 with respect to the coated substrate 1 is started, a portion where the film thickness due to the bead is increased is not formed in the coating start portion. Control coating thickness by properly setting coating conditions such as discharge pressure, discharge volume, slot die movement speed relative to the substrate to be coated, and their rate of change, and match multiple coatings. Thus, it is possible to reduce the film thickness variation at the coating start portion.

  FIG. 3 conceptually shows the film thickness distribution of each coating film by the two slot dies 11 and 21. A broken line is a film thickness distribution of the coating film by the slot die 11 which forms a bead before starting relative movement with respect to the substrate 1 to be coated. The alternate long and short dash line is the film thickness distribution of the coating film by the slot die 21 that does not form a bead before the relative movement to the substrate 1 is started. The solid line is a combination of the film thickness of the coating film by the slot die 11 and the film thickness of the coating film by the slot die 21.

  By using the present invention, the film thickness of the unstable part of the coating film formed at the coating start part is stabilized, and the film thickness can be controlled with high accuracy. Moreover, since the effective area | region of a to-be-coated substrate can be expanded, the effective utilization of a to-be-coated substrate and reduction of a coating area can be aimed at.

DESCRIPTION OF SYMBOLS 1 Substrate to be coated 2 Stage 11 Slot die 12 Coating liquid 13 Storage tank 14 Discharge pipe 15 Pressure pipe 16 Valve 17 Filter 18 Bead 19 Coating film 21 Slot die 22 Coating liquid 23 Storage tank 24 Discharge pipe 25 Pressure pipe 26 Valve 27 Filter 29 Paint film

Claims (3)

  A coating apparatus that performs coating by discharging a coating liquid from a slot tip of a slot die while the slot die moves in one direction relative to the substrate to be coated. A coating apparatus comprising a plurality of slot dies installed in a direction of relative movement with respect to the plurality of slot dies, and a mechanism for independently controlling discharge and discharge conditions of the coating liquid with respect to the plurality of slot dies. .   The coating apparatus according to claim 1, further comprising a mechanism in which the plurality of slot dies move independently with respect to the substrate to be coated.   The coating apparatus according to claim 1 or 2, wherein at least one slot die among the plurality of slot dies is coated without forming a bead before starting to move relative to the substrate. And the plurality of slot dies coat the same region.

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