JP2001321714A - Apparatus for rotary coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute an apparatus for rotary coating which can form a coating film of a uniform thickness without the adhesion of a coating solution to the back of a substrate even when the noncircular substrate is used by using a non-Newtonian fluid as the coating solution. SOLUTION: The coating film is formed by housing the substrate 1 in a container which has a projected shape in which a distance from the substrate is increased gradually toward a middle part and is composed of a lid body 9 having a gas introduction hole 12 in the middle part, a side part 11, and a bottom part 10 having a gas discharge 13 opening in a circumferential fringe part and developing the coating solution 7 while the container is rotated synchronously with the substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spin coating apparatus which applies a coating liquid on a substrate by using a centrifugal force to form a coating film having a uniform thickness.

[0002]

2. Description of the Related Art Conventionally, in a process of manufacturing a semiconductor device, a spin coating apparatus has been widely used for forming a coating film of a photoresist. FIG. 2 schematically shows the configuration of the spin coating apparatus. In the figure, 1 is a substrate on which a coating film is formed, 2 is a rotary chuck, 3 is a motor, 4 is a supply nozzle, 5 is a cup, and 6 is a waste liquid pipe. In the spin coating apparatus shown in FIG. 2, the coating liquid 7 is dropped from the supply nozzle 4 to the center of the substrate 1 fixed to the rotary chuck 2, and the coating liquid 7 dropped by centrifugal force with the rotation of the motor 3 has a substrate radius. The excess coating liquid that spreads in the direction and forms a thin film on the substrate 1 and scatters in the radial direction is caught by the cup 5 and discarded through the waste liquid pipe 6.

[0003]

The above spin coating apparatus is
When a coating film is formed on a circular substrate using a Newtonian fluid as a coating liquid, a coating film having a uniform film thickness can be formed. In the case where the Newtonian fluid is used, when the viscosity decreases as the strain rate increases, the film thickness becomes large at the center of rotation, and a coating film having a uniform film thickness cannot be obtained.

When a non-circular substrate such as a rectangle is used,
The substrate and the air around the substrate do not rotate synchronously, and the coating liquid scattered in the radial direction from the substrate causes turbulence in the air flow around the substrate caused by the rotation of the substrate, causing a phenomenon in which the coating liquid wraps around the back surface of the rectangular edge portion in particular, and the subsequent process And contaminated the transport system, and became a source of garbage.

[0005] An object of the present invention is to solve the above problems and to provide a spin coating apparatus capable of easily forming a coating film having a uniform thickness.

[0006]

According to the present invention, a coating liquid is applied to the center of a substrate, and the coating liquid is applied to the surface of the substrate by centrifugal force while rotating the substrate around a normal line of the substrate at the center. A spin coating apparatus for forming a coating film on the entire surface of a substrate by spreading the substrate, wherein the substrate is accommodated in a container that rotates synchronously with the substrate, and the distance between the container and the substrate surface gradually increases toward the center. A lid having a convex shape, a side wall, and a bottom, wherein a gas inlet is provided at a central portion of the lid serving as a center of rotation, and a gas outlet is provided at a peripheral portion of the side wall or the bottom. It is a spin coating device.

According to the present invention, the gas inlet communicates with the outside air or the pressure fluid generating source, the coating liquid is a non-Newtonian fluid, and the convex shape of the lid is formed within the inscribed circle of the substrate. And the substrate is non-circular as a preferred embodiment.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The features of the spin coating apparatus of the present invention are as follows.
The object is to rotate a substrate stored in a specific container. Such a container has a lid facing the substrate surface, a side wall, and a bottom, and the lid has a convex shape in which the distance from the substrate gradually increases toward the center, and a gas inlet is provided in the center. Have. A gas outlet is provided on the side wall or the bottom peripheral edge of the container.

FIG. 1 is a schematic view showing the configuration of an embodiment of the spin coating apparatus according to the present invention. In the drawing, the same members as those in FIG. 2 are denoted by the same reference numerals, and 1 is a substrate on which a coating film is formed.
Is a rotating chuck that fixes the substrate 1 and rotates with the rotation of the motor 3, 3 is a motor, 5 is a cup for collecting waste liquid, 6 is
Is a waste liquid pipe for guiding waste liquid, 7 is a coating liquid dropped on the substrate 1, 8 is a cover for preventing intrusion of dust and leakage of the scattered coating liquid out of the apparatus, and 9 is a container which rotates synchronously with the substrate 1. Lid, 10 is the bottom of the container, 11 is the side wall of the container, 12
Is a gas inlet provided in the center of the lid 9, and 13 is a gas outlet provided in the side wall 11 of the container, which also serves as a waste liquid port.

In the apparatus shown in FIG. 1, the outside air communicates with the gas inlet 12, and when the coating liquid 7 is dropped on the center of the substrate 1 and the substrate 1 is rotated, the air in the container becomes gaseous. The gas is discharged to the outlet 13 and the pressure in the container is reduced, so that gas flows in from the gas inlet 12. The inflowing gas collides with the coating liquid 7 dropped on the substrate 1 and suppresses the film thickness of the coating film from increasing at the center of rotation. The flattening effect of the coating film thickness due to the gas flow becomes stronger when the substrate is rotated at a high speed, but by adjusting the convex shape of the lid 9 to adjust the gradual increase and decrease of the distance from the substrate, It is possible to adjust. Further, when the rotation speed of the substrate is low, the pressure in the container may not be sufficiently reduced, and the gas flow from the gas inlet 12 to the gas outlet 13 may not be sufficiently formed. By adjusting the flow rate and pressure of the gas flowing from the gas introduction port 12 by connecting the gas introduction port 12 to a pressure fluid generation source (not shown), the film thickness flattening effect can be adjusted.

When a non-circular substrate such as a rectangle is used as the substrate 1, by forming the convex shape of the lid 9 in an inscribed circle of the substrate 1, the gas in the container is removed together with the substrate 1. Since it moves in the circumferential direction of rotation, the turbulence of the air flow generated at the edge of the substrate 1 is extremely small as compared with the conventional case, thereby preventing the coating liquid 7 from flowing to the back surface of the substrate 1 and contaminating the transport system in a later process. And generation of dust can be suppressed.

Excess coating liquid 7 scattered from the substrate 1 in the radial direction collides with the side wall 11, is discharged out of the container from a gas discharge port provided in the bottom 10, passes through the cup 5, passes through the waste liquid pipe 6, and then passes through the apparatus. It is discharged outside.

[0013]

As described above, the spin coating apparatus of the present invention can easily form a coating film having a uniform thickness even when the coating liquid is a non-Newtonian fluid or the substrate has a non-circular shape. Thus, contamination of the transfer system in the subsequent process and generation of dust can be prevented. Therefore, the choice of a material for forming a thin film is widened, and it is very useful for manufacturing a more excellent element and simplifying a manufacturing process, particularly in a semiconductor element manufacturing field.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of an embodiment of a spin coating device of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a conventional spin coating device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Rotary chuck 3 Motor 4 Coating liquid supply nozzle 5 Waste liquid collection cup 6 Waste liquid pipe 7 Coating liquid 8 Cover 9 Lid 10 Bottom 11 Side wall 12 Gas inlet 13 Gas outlet

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Claims (5)

[Claims] 1. A coating liquid is applied to a central portion of a substrate, and the coating liquid is spread on the surface of the substrate by centrifugal force while rotating the substrate around a normal line of the substrate at the central portion to coat the entire surface of the substrate. A spin coating apparatus for forming a film, wherein the substrate is housed in a container that rotates synchronously with the substrate, and the container has a lid having a convex shape in which a distance from the substrate surface gradually increases toward a central portion. , A side wall and a bottom portion, wherein a gas inlet is provided at a central portion of a lid serving as a center of rotation, and a gas outlet is provided at a peripheral portion of the side wall or the bottom portion. 2. The spin coating apparatus according to claim 1, wherein the gas introduction port communicates with outside air. 3. The spin coating device according to claim 1, wherein the gas inlet communicates with a pressure fluid generation source. 4. The spin coating apparatus according to claim 1, wherein the coating liquid is a non-Newtonian fluid. 5. The spin coating apparatus according to claim 1, wherein the convex shape of the lid is formed in an inscribed circle of the substrate, and the substrate is non-circular.