JPH04247265A - Rotary coating device - Google Patents

Abstract

PURPOSE:To accumulate a stringy material in a recess 6 even if a viscous coating soln. or a negative resist is splashed by centrifugal force and to prevent the short-cutting of the stringy material to the rear of a substrate by providing a protrusion 5 on the upper end of a flow straightening member 4. CONSTITUTION:A protrusion 5 is provided on the upper end of a flow straightening member 4. The tip of the protrusion 5 is placed within the periphery (edge) of a substrate 1. A recess 6 is inevitably formed on the inclined surface of the periphery of the member 4. When the substrate 1 such as a wafer is rotated, a viscous coating soln. or a negative resist is splashed and strung by centrifugal force, however, the stringy material is accumulated in the recess 6, and the rear of the substrate is kept clean.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spin coater for uniformly coating a substrate surface with a coating liquid using centrifugal force. More specifically, it is a high-viscosity coating liquid, or even a liquid that is not very viscous, such as a negative resist, in which the excess coating liquid that scatters from the substrate due to centrifugal force becomes stringy during spin coating. The present invention relates to a spin coating device suitable for coating.

0002

[Prior Art] A spin coating machine applies a coating solution such as a photoresist solution, a developer, an etching solution, or a liquid dopant solution to the surface of a semiconductor substrate, a glass substrate such as liquid crystal glass, a ceramic substrate, etc. This is a device that rotates the coating liquid to uniformly coat the surface of the substrate.

[0003] Conventionally, this type of device has been proposed, for example, the one shown in the cross-sectional view of FIG. In FIG. 3, reference numeral 1 indicates a wafer such as silicon, which is a semiconductor substrate, as an example of a substrate, and 2
1 is a spindle for rotating the wafer 1 via a spin chuck 3; 3 is a spin chuck for supporting the wafer; 4 is an annular rectifying member provided below the wafer 1 for adjusting the airflow below the wafer 1; , 7 is a recess provided inside the upper end surface of the rectifying member 4, 8 is a cup provided to surround the rotating wafer 1, 9 is a nozzle for supplying the coating liquid to the wafer 1, and 10 is a cup. This is an exhaust means for exhausting the inside.

[0004] The operation of the conventional spin coating machine configured as above will be explained.

A predetermined amount of the coating liquid is supplied from the nozzle 9 onto the wafer 1, and then the wafer 1 is rotated at a rotational speed of, for example, several thousand rpm.
p. The coating liquid is spread uniformly on the wafer 1, and then, if necessary, the coating film is dried and cured by heating. During this spin coating process, in order to prevent droplets of the coating liquid from adhering to the front and back surfaces of the wafer 1, the inside of the cup is forcibly evacuated using the exhaust means 10, thereby circulating clean air, nitrogen gas, etc. from above. I'm letting you do it.

[0006]

However, according to the conventional example, when a high viscosity coating liquid is applied onto the wafer 1 and the wafer 1 is rotated at high speed, the high viscosity coating liquid spreads onto the inner peripheral surface of the cup 8 and the like. There is a problem that not only does it adhere to the inclined surface of the rectifying member 4, but it also accumulates at the upper end of the rectifying member, and a part of it adheres to the back surface of the substrate.

[0007] When we investigated the cause of this technical problem, we found that
I have come to believe that this is caused by the following phenomenon. That is, the excess coating liquid scattered by the centrifugal force is scattered as if pulling a string from the substrate, and its tip attaches to the inner peripheral surface of the cup 8, and at that moment, the peripheral edge of the substrate and the inner peripheral surface of the cup 8 are connected. It looks like it is tied with a thread made of a highly viscous coating liquid. Then, since the substrate is rotating, the middle part of the threaded material moves in a short path over the rectifying member 4, enters between the rectifying member 4 and the substrate, and spins. It is thought that the stringy objects become entangled with the chuck 3 and the like and accumulate below the substrate 1, and of the accumulated stringy objects, a portion that partially protrudes upward is attached to the back surface of the wafer 1. Note that if stringy matter of the coating liquid adheres to the back surface of the wafer 1, an undesirable additional work step will be required to remove it, or the wafer 1 will have to be discarded from the semiconductor manufacturing process. .

In order to solve the problems of the prior art, the present invention prevents the high viscosity coating liquid from accumulating on the rectifying member 4 even if it is blown away by centrifugal force and becomes stringy, thereby preventing the substrate from being accumulated. An object of the present invention is to provide a rotary coating device that keeps the back side of the product clean.

[0009]

Means for Solving the Problems In order to achieve the above object, the spin coating apparatus of the present invention includes a spin chuck that rotates while holding a substrate substantially horizontally, and a spin chuck that is provided below the substrate and rotates the substrate. A rotary coating device comprising an annular rectifying member that adjusts the airflow below the rotating substrate and a cup provided to surround the rotating substrate and the rectifying member, and exhausting air between the rectifying member and the cup. , the rectifying member has a truncated conical shape that widens downward, and includes a protrusion at the upper end that protrudes radially outward from the side surface of the truncated conical shape to a depth equal to or smaller than the outer diameter of the substrate. .

[0010] In the above description, the truncated conical shape refers to a shape obtained by cutting off the tip of a cone.

[0011]

[Operation] According to the configuration of the present invention, the rectifying member has a truncated conical shape that expands downward, and the upper end protrudes radially outward from the side surface of the truncated conical shape to a point equal to or smaller than the outer diameter of the substrate. Because it is equipped with a protrusion, centrifugal force causes the high viscosity coating liquid and negative resist to scatter in a stringy manner, and the tips of the scattered objects adhere to the inner circumferential surface of the cup, causing the middle part of the stringy object to scatter. However, even if the substrate becomes tangled with the substantially partially conical side surface of the rectifying member due to rotation, the position where the stringy material becomes entangled on the substantially partially conical side surface of the rectifying member is kept from the substantially partially conical side surface by the protrusion. Since it is prevented from moving upward along the conical side surface, the short path under the substrate is eliminated, and the scattered coating liquid does not accumulate between the substrate and the rectifying member. You can keep the back side clean.

0012

[Example] The present invention will be explained in more detail below using Examples. Note that the present invention is not limited to the following examples.

FIG. 1 is a sectional view of a spin coating machine according to a first embodiment of the present invention. In FIG. 1, 5 is an annular protrusion provided at the upper end of the rectifying member 4. As shown in FIG. The tip of the protruding portion 5 is located inside the outer peripheral portion (edge portion) of the substrate 1. By providing the protrusion 5, a recess 6 is inevitably formed on the inclined surface of the outer periphery of the flow regulating member 4, and stringy substances caused by scattered objects of the high-viscosity coating liquid are effectively collected in this recess 6. be able to. For example, like a spool of thread. Other part numbers are the same as those in FIG. 3, so their explanation will be omitted. Projection part 5
The shape may be of any shape, such as an eave shape, a flange shape, a plate shape, etc., and does not necessarily have to be annular. Further, the shape of the recessed portion 6 may be any shape, and a groove-like shape, a gently curved recess, etc. can be adopted.

The material of the rectifying member 4 having the protrusion 5 may be any material such as resin or metal, and is preferably a molded plastic such as polypropylene.

The operation of the first embodiment configured as described above will be explained below.

The wafer 1 is rotated at a low speed, and a predetermined amount of a high viscosity coating liquid (for example, a negative resist of 100 centipoise or more) is supplied onto the wafer 1 from the nozzle 9. Then, the rotation speed is increased to, for example, several thousand rpm. p. The coating liquid is uniformly spread over the wafer 1 to coat it. At this time, even if the high viscosity coating liquid scatters from the top of the wafer 1 and a stringy object is generated, it will accumulate in the recess 6 and the middle part of the stringy object will short-circuit below the substrate. You can prevent passing.

Next, FIG. 2 is a sectional view of a spin coater according to a second embodiment of the present invention. In FIG. 2, reference numeral 5 denotes a protrusion having an arcuate cross section and provided at the upper end of the rectifying member 4. As shown in FIG. A recessed portion 6 is formed on the lower side of the protruding portion 5 as in the first embodiment. Stringy substances caused by scattering of the high-viscosity coating liquid can be collected in the recessed portion 6.

As explained above, according to this embodiment, since the protrusion 5 is provided at the upper end of the rectifying member 4 inside the edge of the wafer 1, it is possible to apply a high viscosity coating liquid onto the wafer 1. Then, the spindle 2 is rotated at high speed, and the high viscosity coating liquid is attached in the form of droplets to the inner circumferential surface of the cup 8 and the inclined surface of the rectifying member 4, and the coating liquid is stretched in a state where a thread is drawn from the droplets. Even if a state in which the filament is wrapped around the rectifying member 4 occurs, the wrapped filament is prevented from going above the protrusion 5 and accumulates in the recess 6. As a result, it is possible to prevent the back surface of the substrate 1 from getting dirty.

[0019]Although the above embodiments have shown examples of wafers,
The present invention applies a photoresist solution, a developer, an etching solution, a liquid dopant solution, etc. to the surface of a semiconductor substrate, a glass substrate such as liquid crystal glass, a ceramic substrate, a plastic substrate, etc., and then rotates the substrate to remove the coating solution. It can be applied to any device that can uniformly coat the surface of a substrate. In addition, the high viscosity coating liquid that can be applied to the present invention is effective for liquids used as protective films for optical discs, polyimide resin liquids as flattening films for wafers, negative resist liquids, and liquids used when forming thick films. .

[0020]

[Effects of the Invention] As described above, according to the present invention, the rectifying member has a truncated conical shape that expands downward, and the upper end extends radially outward from the truncated conical side surface to a point equal to or smaller than the outer diameter of the substrate. Since the projecting part is provided, even if a high viscosity coating liquid or negative resist is blown away by centrifugal force and becomes stringy, the stringy material is collected in the recessed part on the side of the rectifying member, thereby preventing the substrate from flowing. It is possible to prevent the stringy material from accumulating on the back side and keep the back side of the substrate clean.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a spin coating machine according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a spin coating machine according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a conventional spin coating machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Wafer, 2... Spindle, 3... Spin chuck, 4... Rectification member, 5... Protrusion part, 6... Recessed part on the outer peripheral surface of the rectifying member, 7... Recessed part in the upper end surface of the rectifying member, 8
...Spin cup, 9...Nozzle, 10...Exhaust means.

Claims (1)

[Claims] 1. A spin chuck that rotates while holding a substrate substantially horizontally, an annular rectifying member provided below the substrate and regulating airflow below the rotating substrate, a rotating substrate and a rectifying member. A rotary coating device is provided with a cup provided so as to surround a flow regulating member, and is configured to exhaust air between a flow regulating member and the cup, wherein the flow regulating member has a truncated conical shape that widens downward, and has a truncated conical shape at an upper end. A rotary coating device characterized by having a protrusion that protrudes radially outward from a side surface of a conical head to an extent equal to or smaller than the outer diameter of a substrate.