JPH08153668A - Applicator of viscous materials - Google Patents

Abstract

PURPOSE: To prevent accurately a re-adhesion of excessive materials onto a substrate without causing to increase the entire device. CONSTITUTION: In an application of viscous materials, the viscous materials are dripped on a substrate 1 held horizontally in a chuck part 2, and further the chuck part 2 is rotated at a high speed to form a thin film on the substrate 1. The applicator is provided with an air current control cover 8 that can be arranged near to the chuck part 2. The air current control cover 8 has a skirt part 9 extending downwardly and inclinedly according to an outer peripheral shape of the substrate 1, and can further be supported so as to be arranged near to the skirt part 9 with respect to a substrate holding surface of the chuck part 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a viscous material coating apparatus used for forming a uniform thin film on a substrate to be processed.

[0002]

2. Description of the Related Art Generally, a spin coating method is widely known as a means for forming a uniform thin film on a substrate such as a semiconductor wafer (hereinafter simply referred to as "wafer"). A coating apparatus for that purpose is called a spin coater, which holds a wafer on a vacuum chuck, drops a resist solution (viscous material) on the wafer from a nozzle, and rotates the wafer together with the vacuum chuck. As a result, the resist solution is spread on the wafer by centrifugal force, and the solvent in the resist solution is evaporated to obtain a solidified resist film.

FIG. 6 is a schematic side view showing a conventional viscous material coating apparatus. In FIG. 6, 31 is a substrate (wafer or the like) that is a workpiece, 32 is a chuck portion that holds the substrate 31 by means such as vacuum suction, and 33 is a chuck portion 32.
A spin motor for rotating the viscous material, 34 a viscous material such as resist liquid, 35 a coating nozzle serving as a supply port for the viscous material 34,
Reference numeral 36 is a solvent supply nozzle that dissolves excess material in the peripheral portion of the substrate, 37 is a scattering prevention cover that prevents scattering of the viscous material 34 and solvent, and 38 is a discharge port for discharging the viscous material 34 and solvent gas to the outside of the apparatus. is there.

When forming a thin film on a substrate using a conventional coating apparatus, first, the substrate 31 is supplied to the chuck portion 32 by a substrate transfer device (not shown), and this is fixed by a fixing means such as vacuum suction. Hold. Next, after an appropriate amount of the viscous material 34 is dropped from the coating nozzle 35 onto the substrate 31, the spin motor 33 is driven to rotate the substrate 31 together with the chuck portion 32 at a high speed for a predetermined time. As a result, the substrate 31
Since the viscous material 34 applied to the substrate is diffused to the peripheral portion of the substrate by the centrifugal force accompanying the driving of the spin motor 33, the thickness of the viscous material 34 on the substrate 31 is reduced as a whole. After that, the solvent contained in the viscous material 34 evaporates and the film thickness on the substrate 31 further decreases. However, the viscosity of the viscous material 34 increases with it, and the decreasing tendency of the film thickness due to the centrifugal force slows down. Finally, the decrease of the diffusion coefficient in the liquid phase makes it difficult for the solvent to move in the film, the evaporation from the gas-liquid interface becomes impossible, and the decrease of the film thickness is completely stopped, and a thin film is formed on the substrate 31. Will be done. After that, in order to remove the excess material adhering to the peripheral edge of the substrate 31, the solvent is dropped from the solvent supply nozzle 36 to the peripheral edge of the substrate, which reduces the viscosity of the excess material at the peripheral edge of the substrate,
It is blown outward by the centrifugal force. Most of the surplus material thus blown off collides with the inner wall surface of the scattering prevention cover 37 and is directly discharged to the outside of the apparatus through the discharge port 38.

[0005]

However, although it is a very small part, after the surplus material scattered from the peripheral edge of the substrate collides with the inner wall surface of the scattering prevention cover 37, it bounces back to the substrate 31 side and reattaches to the film surface. However, there is a problem in that this causes local unevenness of the film thickness, which reduces the yield of the coating process. As measures against this, there has been proposed a device in which the shatterproof cover 37 is upsized so that its wall surface is sufficiently separated from the peripheral portion of the substrate, and the shatterproof cover 37 has a shape and the like devised. In the former case, it is not a good idea because it causes an increase in the size of the entire apparatus, and in the latter case, there is no regularity in the direction of the bounce on the cover surface, so a sufficient effect cannot be obtained.

The present invention has been made to solve the above problems, and its purpose is to reliably prevent redeposition of excess material on a substrate without increasing the size of the entire apparatus. An object of the present invention is to provide a viscous material coating device that can be used.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and a viscous material is dropped on a substrate held horizontally by a chuck part and the chuck part is rotated at a high speed. It is a coating device for a viscous material that forms a thin film on a substrate by means of an air flow control cover that can be arranged near the chuck unit 2. The airflow control cover has a skirt portion that extends obliquely downward following the outer peripheral shape of the substrate, and is supported so that the skirt portion can be arranged close to the substrate holding surface of the chuck portion.

[0008]

In the viscous material coating apparatus of the present invention, the skirt portion of the airflow control cover is disposed in proximity to the substrate held by the chuck portion with a predetermined gap, and the substrate is rotated together with the chuck portion in this state. By doing so, an air flow is generated outward in the gap between the substrate peripheral edge and the skirt, and this air flow causes excess material scattered from the substrate peripheral edge and excess material splashed from the scattering prevention cover to move downward (downstream). Side) will be washed away. Further, even if there is a surplus material that has bounced back to the substrate side against the air flow, the surplus material only adheres to the surface of the air flow control cover and does not re-adhere to the substrate surface.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic side view for explaining an embodiment of a viscous material coating apparatus according to the present invention. In the coating apparatus shown in FIG. 1, 1 is a substrate to be a workpiece,
Reference numeral 2 denotes a chuck portion that holds the substrate 1 by suction, for example, by vacuum suction force. The drive shaft of the spin motor 3 is connected to the central portion on the lower surface side of the chuck portion 2, so that the chuck portion 2 is driven to rotate together with the drive of the spin motor 3. On the other hand, an application nozzle 4 for supplying a viscous material such as a resist liquid is movably provided above the chuck portion 2. The viscous material supplied from the application nozzle 4 is applied to the chuck portion 2. It is dropped on the substrate 1 thus held.

Reference numeral 5 in the drawing denotes a solvent supply nozzle for dissolving the excess material attached to the peripheral edge of the substrate 1. The solvent supply nozzle 5 can be brought close to the peripheral edge of the substrate 1 held by the chuck portion 2. It is installed in. Further, reference numeral 6 in the drawing is a scattering prevention cover for preventing scattering of excess material to the outside of the apparatus, and the chuck portion 2 is provided inside the scattering prevention cover 6.
Is housed. A discharge port 7 for discharging excess material and solvent gas to the outside of the device is provided at the bottom of the scattering prevention cover 6.

Here, the feature of the present invention is that the air flow control cover 8 is provided to prevent the redeposition of the surplus material on the substrate surface. The air flow control cover 8 has a cylindrical structure as shown in the drawing, and a skirt portion 9 that extends obliquely downward is provided on the lower end side thereof according to the outer peripheral shape of the substrate 1. The airflow control cover 8 is obtained by, for example, integrally molding a resin or bending or welding a thin metal plate, and in this embodiment, the skirt portion 9 provided on the lower end side of the cover has an angle of about 30 °. It extends downward with an inclination angle. The inclination angle of the skirt portion 9 may be appropriately set in consideration of the outer diameter of the cover, the skirt length, and the outer diameter of the substrate 1 to be processed. Further, the airflow control cover 8 is supported by a drive unit (not shown) so as to be movable in the axial direction (vertical direction in FIG. 1) of the spin motor 3, and when supplying the viscous material onto the substrate 1, In order to avoid positional interference with the coating nozzle 4, it has a structure that can be retracted above the chuck portion 2.

Next, the operation procedure of the coating apparatus of this embodiment will be described. First, the substrate 1 to be processed is supplied to the chuck unit 2 by a substrate transfer device (not shown). As a result, the substrate 1 is suction-held by the vacuum suction force of the chuck portion 2. At this point, the coating nozzle 4 and the air flow control cover 8 are retracted to a position sufficiently separated from the chuck portion 2 in order to avoid positional interference with the substrate transfer device. Then, as shown in FIG. 2, the coating nozzle 4 advances above the substrate 1 by a nozzle driving unit (not shown), and an appropriate amount of the viscous material 10 is discharged from the tip of the nozzle, and the viscous material 10 is discharged onto the substrate 1. Let it drip. After that, when the dropping of the viscous material 10 is completed, the coating nozzle 4 retreats to a position separated from the chuck portion 2 again.

Then, by a drive unit (not shown),
As shown in FIG. 3, the airflow control cover 8 starts descending toward the chuck portion 2 and stops when a predetermined gap, for example, about 5 mm, is obtained between the substrate 1 and the skirt portion 9. . Then, the spin motor 3 is driven to rotate the substrate 1 together with the chuck portion 2 at a high speed for a predetermined time. As a result, the substrate 1 has a diffusion effect similar to the conventional one.
A thin film will be formed on top.

At this time, since the airflow control cover 8 is arranged close to the substrate 1 held by the chuck portion 2 with a predetermined gap above the substrate 1, the substrate is driven by the rotation of the spin motor 3. An airflow is generated in the gap between the 1 and the skirt portion 9. As shown by the chain double-dashed line in FIG. 4, this air flow follows the inclination angle of the skirt portion 9 provided on the air flow control cover 8 and flows obliquely downward from the peripheral edge of the substrate.
Further, the airflow thus flowing out from the gap between the skirt portion 9 and the substrate 1 merges with the airflow outside the cover (indicated by the one-dot chain line in the figure) due to the exhaust action from the exhaust port 7, and then flows under the chuck portion 2. It is exhausted through the exhaust port 7 to the outside of the apparatus.

Therefore, due to the centrifugal force during rotation, the substrate 1
Since the surplus material blown off from the peripheral edge portion is scattered obliquely downward along the flow of the airflow, the surplus material colliding with the scattering prevention cover 6 hardly bounces back to the substrate 1 side. In addition, even if the excess material suddenly rebounds from the scattering prevention cover 6, and even if there is excess material that has rebounded against the flow of the air current,
Since the surface of the substrate 1 is protected by the airflow control cover 8, the surplus material that has rebounded only adheres to the cover surface, and does not redeposit on the film surface. Further, thereafter, with respect to the surplus material (including the solvent) blown off from the peripheral portion of the substrate due to the supply of the solvent from the solvent supply nozzle 5, the mist is re-generated on the film surface by the same protective function of the air flow control cover 8. Adhesion is reliably prevented.

Before the solvent is supplied from the solvent supply nozzle 5, the surplus material blown off from the peripheral portion of the substrate has a certain degree of viscosity, so most of it adheres to the wall surface of the scattering prevention cover 6 and the substrate 1 Bounce to the side is small. On the other hand, since the surplus material scattered from the peripheral portion of the substrate by the supply of the solvent is liquefied by the solvent, the viscosity is extremely small, and the splash from the scattering prevention cover 6 is correspondingly increased. Therefore, regarding the prevention of the re-adhesion of the surplus material on the substrate surface, a particularly remarkable effect can be obtained with respect to the surplus material scattered from the peripheral portion of the substrate due to the supply of the solvent.

In addition, the airflow control cover 6 is rotatably supported coaxially with the chuck portion 2 by a rotation support unit (not shown) using a motor or the like as a drive source, and the airflow control cover 6 is driven together with the drive of the spin motor 3. If the rotor is rotated in the same direction as the chuck portion 2, a large air flow can be obtained in the gap between the substrate peripheral portion and the skirt portion 9 by the synergistic effect of the rotation of the substrate 1 and the rotation of the air flow control cover 6. it can. As a result, it becomes possible to more reliably prevent the reattachment of the surplus material on the substrate surface.

FIG. 5 is a schematic side view for explaining another embodiment of the viscous material coating apparatus according to the present invention. The feature of the configuration of the coating apparatus shown in FIG. 5 is that a predetermined gas (described later) is provided on the substrate holding surface (upper surface) side of the chuck portion 2.
The point is that a gas supply nozzle 11 for blowing the gas is provided. The gas supply nozzle 11 is connected to a gas supply source (not shown) (such as a compression pump) and blows gas to the chuck portion 2 side through the hollow portion of the tubular airflow control cover 8. is there.

The gas supply nozzle 1 thus equipped
In No. 1, after the airflow control cover 8 is arranged close to the chuck portion 2, the airflow control cover 8 advances above the airflow control cover 8. Then, as the spin motor 3 is driven, the substrate 1 together with the chuck portion 2 starts rotating, and at the same time, the gas delivered from a gas supply source (not shown) is blown toward the surface of the substrate 1. As a result, the flow velocity of the air flow obtained in the gap between the substrate peripheral edge and the skirt portion 9 is increased, so that the excess material scattered from the substrate peripheral edge and the excess material splashed from the scattering prevention cover 9 can be more effectively downstream. Therefore, the redeposition of the surplus material on the substrate surface can be prevented more reliably.

The gas component supplied from the gas supply nozzle 11 may be air or nitrogen, but in such a case, the hardening of the viscous material coated on the substrate is promoted, so that the film thickness control is performed. In consideration of the film thickness, the uniformity of the film thickness, and the like, it is preferable to employ a gas containing a solvent component of the viscous material and appropriately suppress the hardening of the viscous material.

[0021]

As described above, according to the present invention,
Without inviting an increase in the size of the entire apparatus as in the conventional case, the skirt portion of the airflow control cover is arranged closely on the substrate held by the chuck portion, and the substrate is rotated together with the chuck portion in this state, The air flow obtained in the gap between the peripheral portion of the substrate and the skirt portion can prevent the reattachment of the surplus material on the substrate surface. Further, since the surface of the substrate is protected by the airflow control cover, even if there is excess material that has bounced back to the substrate side against the airflow,
It is possible to reliably prevent redeposition on the substrate surface. As a result, the unevenness of the film thickness due to the redeposition of the surplus material is eliminated, so that the yield in the coating process is significantly improved, and the manufacturing cost such as the processing cost and the material cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic side view illustrating an embodiment of a viscous material coating apparatus according to the present invention.

FIG. 2 is a diagram (No. 1) for explaining the operation of the apparatus in the embodiment.

FIG. 3 is a diagram (No. 2) for explaining the operation of the apparatus in the embodiment.

FIG. 4 is a diagram illustrating an airflow generation state by an airflow control cover.

FIG. 5 is a schematic side view illustrating another embodiment of the present invention.

FIG. 6 is a schematic side view illustrating a conventional device.

[Explanation of symbols]

1 substrate 2 chuck part 8 airflow control cover 9 skirt part 11 gas supply nozzle

Claims (3)

[Claims] 1. A viscous material coating apparatus for dropping a viscous material onto a substrate held horizontally by a chuck section and rotating the chuck section at a high speed to form a thin film on the substrate, And a cylindrical airflow control cover that has a skirt portion that extends obliquely downward in accordance with the outer peripheral shape of the above and that is supported so that the skirt portion can be placed close to the substrate holding surface of the chuck portion. Characteristic viscous material application device. 2. The viscous material coating apparatus according to claim 1, wherein the air flow control cover is rotatable in the same direction as the chuck portion. 3. The viscous material coating apparatus according to claim 1, wherein a gas supply nozzle for blowing gas is provided on the substrate holding surface side of the chuck section through the air flow control cover.