JP4586445B2 - Slit coat type coating device - Google Patents

Description

  The present invention relates to a slit coating type coating apparatus and a slit coating type coating method for flowing a predetermined solution from the tip of a nozzle and uniformly coating the solution on the surface of a substrate.

  As a coating apparatus for applying a predetermined solution (solvent) such as a resist material or an insulating material to a substrate such as a semiconductor wafer or a glass substrate, for example, the solution is caused to flow out from the tip of a nozzle by capillary action, and the solution is applied to the substrate surface. There is a slit coat type coating apparatus for coating (see, for example, Patent Document 1).

  After applying the solution over the entire surface of the substrate by such a slit coat type coating apparatus, the substrate is generally disposed by, for example, placing the substrate on a hot plate and drying the applied solution. A coating film is formed on the surface.

  In such a slit coat type coating apparatus, in order to uniformly apply the solution to the substrate, it is necessary to apply the solution slowly. Therefore, the solution applied to the substrate is gradually dried in the meantime, There is a problem that sink marks or the like occur. In particular, when a thin coating film is formed using a material having a relatively low viscosity of the solution to be used, such a problem appears remarkably. Therefore, a method for forcibly drying the substrate surface by spraying a dry gas on the substrate surface has been proposed (see, for example, Patent Document 2). However, with this method alone, the gas that dries the surface of the substrate remains in a closed space in a damp state, and the damp gas is mixed with the dry gas and the dry gas having a desired humidity or lower is applied to the substrate surface. It is difficult to supply. In particular, in a substrate having irregularities and holes, drying unevenness and sink marks around the irregularities and holes are remarkably generated, so that it is necessary to stably supply a dry gas to the surface of the substrate.

JP-A-6-343908 (FIGS. 1-2 and 2-4) Japanese Patent Laid-Open No. 2002-110535 (FIG. 1, pages 1 to 11)

  In view of such circumstances, the present invention provides a slit coat type coating apparatus and a slit coat type coating method capable of forming a coating film having a uniform film thickness on a substrate by preventing the occurrence of drying unevenness and sink marks. The task is to do.

According to a first aspect of the present invention for solving the above-described problems, a holding table for holding a substrate and a surface of the substrate held by the holding table are arranged so as to face each other and predetermined toward the surface of the substrate. A coating head having a slit-like nozzle opening that flows out the coating solution, and the coating solution is applied to the surface of the substrate by relatively moving the holding table and the coating head in the horizontal direction. And spraying means for spraying a dry gas toward the surface of the substrate on which the coating solution has been applied, drying the coating solution on the substrate surface with the dry gas sprayed from the spraying means, and The gas obtained by drying the coating solution is forcibly exhausted in a slit coat type coating apparatus.
In the first aspect, since the gas obtained by drying the coating solution on the substrate surface is not sprayed on the substrate surface again, the coating solution on the substrate surface can be satisfactorily dried. A uniform coating film can be formed.

According to a second aspect of the present invention, in the first aspect, the spray unit has a slit-like nozzle opening, and the spray unit and the holding table are moved relative to each other in the horizontal direction to apply to the substrate surface. The slit coating type coating apparatus is characterized in that the applied coating solution is dried.
In the second aspect, the coating solution can be dried relatively easily and satisfactorily.

According to a third aspect of the present invention, in the first or second aspect, the holding table is rotatably held around a support shaft extending in the surface direction of the holding table, and the ejection unit is The slit coat type coating apparatus is characterized in that the holding table is disposed on the side opposite to the coating head.
In the third aspect, when the coating solution on the substrate surface is dried, drying of the coating solution in the coating head by the dry gas sprayed by the spraying unit is prevented.

A fourth aspect of the present invention is the slit coat type coating apparatus according to any one of the first to third aspects, wherein the pressure of the dry gas is 0.1 MPa or more.
In the fourth aspect, the coating solution on the substrate surface can be dried well in a relatively short time, and a coating film having a uniform thickness can be formed on the substrate surface.

A fifth aspect of the present invention is the slit coat type coating apparatus according to any one of the first to fourth aspects, wherein the dry gas has a relative humidity of 20% or less.
In the fifth aspect, the coating solution can be reliably dried in a relatively short time.

A sixth aspect of the present invention is the slit coat type according to any one of the first to fifth aspects, wherein the spraying means sprays a dry gas heated to a predetermined temperature toward the substrate surface. In the applicator.
In the sixth aspect, the drying time of the coating solution can be greatly shortened, and the uniformity of the coating film is also improved.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, an ion supply unit that supplies ions in the vicinity of the surface of the substrate on which the coating solution is applied is provided in proximity to the ejection unit. It is in the slit coat type coating device characterized by having.
In the seventh aspect, since the generation of static electricity can be prevented when the dry gas is jetted from the jetting means, the coating solution for the substrate can be further satisfactorily dried.

According to an eighth aspect of the present invention, a holding table for holding a substrate and a surface of the substrate held by the holding table are arranged opposite to each other and a predetermined coating solution flows out toward the surface of the substrate. A coating head having a slit-like nozzle opening that moves in a horizontal direction to apply the coating solution onto the surface of the substrate; and the coating solution that is continuously performed after the coating step. A drying step of drying the coating solution on the surface of the substrate by spraying a drying gas toward the surface of the substrate on which the coating is applied, and an exhausting step of forcibly exhausting the gas after drying the coating solution. In a slit coat type coating method.
In the eighth aspect, since the gas obtained by drying the coating solution on the substrate surface is not sprayed on the substrate surface again, the coating solution on the substrate surface can be dried satisfactorily. A uniform coating film can be formed.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is a perspective view showing a schematic configuration of a slit coat type coating apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view of a main part of the slit coat type coating apparatus. As shown in FIG. 1, a slit coat type coating apparatus 10 includes a holding table 20 that holds a substrate 1 such as a silicon wafer or a semiconductor substrate, a coating head 30 provided on the substrate 1 side of the holding table 20, and a substrate 1. A storage means 40 for supplying the coating solution 2 to be applied to the coating head 30, an injection means 50 for injecting dry gas, and an exhaust means (also referred to as an exhaust device) 60 for forcibly exhausting the gas. Although not shown, the holding table 20, the coating head 30, the storage unit 40, the ejection unit 50, and the like are arranged in a predetermined sealing space, and the exhaust unit 60 will be described later in detail. The gas flowing in the stop space is forcibly exhausted to the outside.

  In the present embodiment, the holding table 20 holds the substrate 1 on the lower surface in the vertical direction. That is, the substrate 1 is held on the holding table 20 so that the surface thereof is directed downward in the vertical direction. The method for holding the substrate 1 by the holding table 20 is not particularly limited, and examples thereof include a method using suction such as a vacuum pump. The holding table 20 is provided so as to be linearly movable along the surface direction of the substrate 1 by a table driving means such as a driving motor (not shown).

  Further, the holding table 20 is rotatably held by, for example, a support shaft 25 provided at the center in the moving direction. In other words, the holding table 20 can be rotated at least 180 degrees around the support shaft 25 to invert the holding table 20.

  The coating head 30 has a slit-like nozzle opening 31 that opens upward in the vertical direction and flows out the coating solution 2 supplied from the storage means 40, and a solution reservoir 32 that communicates with the nozzle opening 31. Further, the coating head 30 is held by a device body (not shown) so as to be movable in the vertical direction, and the distance between the tip of the coating head 30 and the surface of the substrate 1 is, for example, the kinematic viscosity of the coating solution 2 or the coating solution 2. In consideration of the wettability with respect to the substrate 1, the thickness of the coating solution 2 applied to the substrate 1, and the like are adjusted as appropriate.

  The storage unit 40 includes a storage tank 41 that holds the coating solution 2, and a supply pipe 42 that has one end connected to the coating head 30 and the other end connected to the storage tank 41. The applied coating solution 2 is supplied to the coating head 30 via the supply pipe 42.

  When the coating solution 2 is supplied from the storage tank 41 of the storage means 40 to the coating head 30 via the supply pipe 42 and the coating solution 2 is filled into the liquid reservoir 32 of the coating head 30, The coating solution 2 rises to the tip of the nozzle opening 31 by capillary action. As a result, the coating solution 2 is uniformly filled in the slit-shaped nozzle openings 31. Then, the coating head 30 is raised from this state and the coating solution 2 protruding from the nozzle opening 31 is brought into contact with the surface of the substrate 1. In this state, the holding table 20 and the coating head 30 are relative to each other in the surface direction of the substrate 1. Move. For example, in the present embodiment, the coating head 30 is fixed and the holding table 20 is linearly moved in the surface direction of the substrate 1, so that the coating head 30 and the holding table 20 are relatively moved. As a result, the coating solution 2 continuously flows out from the nozzle opening 31, and the coating solution 2 is applied to the surface of the substrate 1 with a uniform thickness.

  In addition, on the surface of the holding table 20 opposite to the coating head 30, an injection unit 50 that injects dry gas toward the surface of the holding table 20 is provided. In the present embodiment, the ejection means 50 is opened toward the lower side in the vertical direction, has an ejection head 52 having a slit-like nozzle opening 51 having a width slightly larger than the width of the substrate 1, and a dry gas in the ejection head 52. And a dry gas supply device 53 for supplying. As will be described in detail later, the coating solution 2 applied onto the substrate 1 is dried by spraying the dry gas sprayed from the nozzle openings 51 of the ejection head 52 onto the surface of the substrate 1 to form a coating film. ing.

  Although the position of the ejection head 52 is not particularly limited, it is desirable that the dry gas ejected from the nozzle opening 51 does not flow into the vicinity of the nozzle opening 31 of the coating head 30. This is because the coating solution 2 in the coating head 30 may be dried by the dry gas sprayed from the coating head 52.

  Further, the dry gas ejected from the nozzle opening 51 of the ejection means 50 may be a dry gas that is not reactive and is clean, but the relative humidity is preferably 20% or less. As the dry gas, specifically, nitrogen, dry clean air, or the like is preferably used. However, since dry clean air requires a cleaning process, in this embodiment, nitrogen is used. Used.

  Further, the exhaust means 60 is provided below the substrate 1, in this embodiment, on the application head 30 side of the holding table 20. The exhaust means 60 forcibly exhausts the gas blown to the coating solution 2 on the substrate 1 to the outside by, for example, sucking the gas around the substrate 1 with a fan or the like. As a result, the dry gas injected by the injection means 50 flows downward at the end face of the substrate 1 in a rectified state, so that only the dried gas is always blown onto the surface of the substrate 1.

  Hereinafter, the slit coat type coating method using such a slit coat type coating apparatus 10 will be described in detail. 3 and 4 are schematic views showing the operation of the slit coat type coating apparatus. First, as shown in FIG. 3A, the substrate 1 is fixed to the lower surface of the holding table 20, the coating head 30 is raised, and the distance between the surface of the substrate 1 and the tip surface of the nozzle opening 31 of the coating head 30 is set. Adjust so that it is at a predetermined interval Specifically, the coating head 30 is raised so that the tip of the coating solution 2 protruding from the nozzle opening 31 is slightly higher than the position of the surface of the substrate 1. In this embodiment, the distance between the coating head 30 and the substrate 1 is adjusted by moving the coating head 30, but of course, the coating head 30 is fixed and the holding table 20 is moved. May be.

  Next, as shown in FIG. 3B, the holding table 20 is linearly moved in the surface direction of the substrate 1, that is, in the horizontal direction by a table driving means (not shown), so that the coating projecting from the nozzle opening of the coating head 30 is performed. The solution 2 comes into contact with the surface of the substrate 1 and application of the coating solution 2 is started. Here, as described above, the air flow on the lower side of the substrate 1 accompanying the movement of the holding table 20 is blocked by the shielding plate 70. In other words, since the drying of the coating solution 2 protruding from the tip of the nozzle opening 31 is suppressed by the shielding plate 70, the coating solution 2 reliably contacts the substrate 1 by the movement of the holding table 20, and the substrate 1 is moved to. Application of the coating solution 2 is started.

  After the application of the coating solution 2 to the substrate 1 is started in this way, the coating solution 2 continuously flows out from the nozzle opening 31 by further moving the holding table 20 as shown in FIG. Then, the coating solution 2 is applied to the entire surface of the substrate 1.

  After the coating solution 2 is applied to the entire surface of the substrate 1 as described above, the holding table 20 is rotated by 180 ° around the support shaft 25 while holding the substrate 1 as shown in FIG. Let That is, the surface of the substrate 1 on which the coating solution 2 is applied is directed upward in the vertical direction. Next, as shown in FIG. 4B, the holding table is linearly reciprocated in the horizontal direction while ejecting nitrogen as a dry gas from the ejection head 52. That is, by moving the holding table 20 while ejecting the dry gas from the nozzle openings 51 of the ejection head 52, the coating gas 2 on the surface of the substrate 1 is dried by spraying the dry gas onto the entire surface of the substrate 1. At this time, it is preferable that the dry gas injected from the nozzle opening 51 of the injection means 50 is rectified. This is because if the air flow of the dry gas is disturbed, the coating solution 2 may be unevenly dried. For example, in the present embodiment, the gas around the substrate 1 is sucked and forcibly exhausted by the exhaust means 60 provided on the lower side of the substrate 1, so that the dry gas blown to the substrate 1 is rectified. ing.

  Further, the gas obtained by drying the coating solution 2 on the surface of the substrate 1 becomes a gas containing a solvent and is damp, but the gas does not remain on the substrate 1 but is exhausted by the exhaust means 60 below the substrate 1. Forced exhaust. Therefore, the wet gas is not sprayed on the surface of the substrate 1 again, so that the dry gas sprayed from the nozzle opening 51 of the spraying means 50 can be efficiently sprayed on the surface of the substrate 1.

  In this embodiment, the coating solution 2 is dried by reciprocating the holding table 20 about 20 times in about 1 minute in a state where a predetermined amount of dry gas is ejected from the nozzle opening 51 of the ejection head 52. ing.

  Further, after coating the coating solution 2 on the surface of the substrate 1, the coating head 30 is stored in a storage unit (not shown) in order to prevent the portion of the nozzle opening 31 from which the coating solution 2 is discharged from drying.

  Here, the drying conditions of the coating solution 2 may be determined as appropriate, but the air volume of the dry gas sprayed from the nozzle opening 51 is 17 (l / s) to 22 (l / s) in the vicinity of the surface of the coating solution 2. s) is preferable. Thereby, the coating solution 2 does not wave, and the dispersion | variation in the film thickness of a coating film can be prevented. The dry gas is preferably sprayed onto the surface of the coating solution 2 in as short a time as possible. Specifically, it is desirable that the wind pressure of the dry gas injected from the nozzle opening 51 is 0.1 MPa or more, particularly about 1 MPa. For this reason, in this embodiment, the drying efficiency is further increased by increasing the wind pressure using a compressor or the like and removing the moisture with a drain. When the compressed dry gas is jetted from the nozzle opening 51, the volume of the compressed dry gas becomes several times larger and comes into contact with the surface of the substrate 1, so that drying can be performed in a shorter time.

  As described above, after the coating process of coating the coating solution 2 on the surface of the substrate 1, the drying process of spraying a dry gas onto the surface of the substrate 1 by the spraying means 50 to dry the coating solution 2 is performed. Further, by performing an exhausting process for forcibly exhausting the gas after drying the coating solution on the surface of the substrate 1, drying unevenness on the surface of the substrate 1, in particular, the unevenness provided on the substrate 1, the hole peripheral portion, sink marks, etc. Thus, a coating film having a uniform film thickness can be satisfactorily formed on the surface of the substrate 1. In particular, in the coating apparatus of the present invention, since the coating process and the drying process can be performed continuously, the time lag from when the coating solution 2 is applied to the surface of the substrate 1 until it is dried can be extremely shortened. Furthermore, since the exhaust process is performed, it is possible to reliably prevent the occurrence of drying unevenness, sink marks, and the like, and a coating film having a uniform film thickness can be formed on the surface of the substrate 1. Moreover, since the coating solution 2 on the substrate 1 can be reliably dried in a relatively short time by spraying a dry gas, for example, a plurality of coating films can be formed continuously.

  In the present embodiment, the normal temperature dry gas is ejected from the nozzle opening 51 of the ejection head 52. However, the present invention is not limited to this, and the dry gas heated to a predetermined temperature is ejected from the nozzle opening 51. May be. Thereby, while being able to shorten drying time, the film thickness of the coating film formed in the surface of the board | substrate 1 can be made further uniform.

  When the temperature of the drying gas is increased with respect to the same wind speed as compared with the drying gas temperature of 20 ° C., drying can be performed in a short time as a result. That is, drying at a speed of 1.3 times at 80 ° C. and 1.5 times at 140 ° C. is possible. In particular, this effect is more remarkable when the boiling point of the coating material is low. However, in order to improve the uniformity, it is desirable that the boiling point is lower than that of the main solvent.

  Further, when the drying solution is sprayed from the nozzle openings 51 of the ejection head 52 to dry the coating solution 2, ions may be supplied to the surface of the coating solution 2 together with the drying gas. For example, an ion generator, so-called ionizer, may be provided in the vicinity of the ejection head 52, and ions may be generated by the ion generation apparatus when the dry gas is ejected from the ejection head 52. Thereby, generation | occurrence | production of static electricity can be suppressed and the coating solution 2 can be dried more favorably.

  Furthermore, in the present embodiment, as the solvent of the coating solution 2, a two-component solvent, for example, a solvent containing PGMEA (propylene glycol monomethyl ether acetate) and ethyl lactate is used. Alternatively, a single-component solvent consisting only of PGMEA may be used. Thereby, the drying time of the coating solution 2 applied to the substrate 1 can be shortened, and the uniformity of the formed coating film can be further improved.

(Other embodiments)
As mentioned above, although embodiment of this invention was described, this invention is not limited to what was mentioned above. For example, in the above-described embodiment, the ejection unit 50 is provided on the side of the holding table 20 opposite to the coating head. However, the present invention is not limited to this, and, of course, the ejection unit is provided on the coating head 30 side of the holding table 20. You may make it provide. However, in this case, it is desirable to prevent the dry gas from flowing into the nozzle opening 31 by covering the nozzle opening 31 of the coating head 30. This is because the coating gas 2 in the nozzle opening 31 may be dried by the dry gas.

  In the above-described embodiment, the coating head 30 and the ejection head 52 are fixed, and the holding table 20 on which the substrate 1 is held is moved so that the coating solution 2 is applied to the surface of the substrate 1 and applied. Although the solution 2 was dried, it is not limited to this. That is, it goes without saying that the holding table 20 may be fixed and the coating head 30 and the ejection head 52 may be moved.

  In the above-described embodiment, the shielding plate 70 is provided in the vicinity of the coating head 30. Of course, the shielding plate 70 may not be provided. Furthermore, in the above-described embodiments, the substrate whose surface is a substantially flat surface has been exemplified. However, the present invention is not limited to this, and the substrate to which the coating solution is applied is, for example, a substrate having a curved surface such as a lens. May be.

It is a perspective view which shows schematic structure of the coating device which concerns on Embodiment 1 of this invention. It is principal part sectional drawing of the coating device which concerns on Embodiment 1 of this invention. It is the schematic which shows the coating method which concerns on Embodiment 1 of this invention. It is the schematic which shows the coating method which concerns on Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate, 2 Coating solution, 10 Slit coat type coating device, 20 Holding table, 30 Coating head, 31 Nozzle opening, 40 Reserving means, 50 Injecting means, 52 Injecting head, 60 Exhaust means, 70 Shielding plate

Claims (6)

A holding table for holding the substrate;
A slit-like nozzle that is disposed so as to face the surface of the substrate held by the holding table and that applies a coating solution to the surface of the substrate by moving relative to the holding table in the horizontal direction. An application head having an opening ;
The application head is disposed on the opposite side to the holding table, and an injection unit that injects a dry gas onto the surface of the substrate on which the application solution has been applied,
A support shaft that rotatably supports the holding table in the surface direction;
The holding table is provided on the coating head side of the holding table, the coating head is moved to one end side of the holding table, and the substrate coated with the coating solution is rotated to the jetting unit side. A slit coat type coating apparatus comprising: an exhaust unit that exhausts the gas ejected from the other end side of the table. A holding table for holding the substrate;
A slit-like nozzle that is disposed so as to face the surface of the substrate held by the holding table and that applies a coating solution to the surface of the substrate by moving relative to the holding table in the horizontal direction. An application head having an opening ;
A storage section for storing the application head;
The application head is disposed on the side opposite to the holding table, and an injection unit that injects a dry gas onto the surface of the substrate on which the application solution has been applied,
A support shaft that rotatably supports the holding table in the surface direction;
The spraying means is provided on the coating head side of the holding table, the substrate coated with the coating solution is rotated to the spraying means side, and the coating head is stored in the storage unit. Exhaust means for exhausting the injected gas;
A slit coat type coating apparatus comprising: 3. The slit coat type coating apparatus according to claim 1, wherein the pressure of the dry gas is 0.1 MPa or more. 4. The slit coat type coating apparatus according to claim 1, wherein the dry gas has a relative humidity of 20% or less. 5. The slit coat type coating apparatus according to claim 1, wherein the spraying unit sprays a dry gas heated to a predetermined temperature toward the substrate surface. 6. The slit coat type according to claim 1, wherein ion supply means for supplying ions to the vicinity of the surface of the substrate on which the coating solution has been applied is provided close to the ejection means. Coating device.

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