JP2929641B2 - Chamber apparatus for spin coating apparatus and coating film forming method - Google Patents

Description

The present invention relates to a chamber apparatus for a spin coating apparatus used for forming a coating film such as an adhesive or a resist on a wafer, and a method using the chamber apparatus. To form a coating film on the surface of the wafer.

[Summary of the Invention]

The present invention surrounds the spin coating device, has at least an air supply duct, an exhaust duct, and a wafer inlet / outlet, and is provided with an airflow control duct near the wafer inlet / outlet, so that the supply amount and exhaust amount of air can be reduced. The present invention relates to a chamber apparatus for a spin coating apparatus and a method of forming a coating film on the surface of a wafer using the chamber apparatus so as to prevent fluctuations in the film thickness of the coating film due to imbalance and to improve safety and health. .

[Conventional technology]

As a method of forming a coating film on a wafer, there is a spin coating method in which a coating liquid such as an adhesive or a resist is dropped on a rotating wafer to perform coating. This spin coating method is excellent in controllability of the thickness of a coating film, adhesion to an underlying substrate, low contamination during coating, and the like, and has been widely put to practical use.

For example, when a resist film is formed on a semiconductor wafer by such a spin coating method, a chamber apparatus for a spin coating apparatus as shown in FIG. 3 has been conventionally used.

As shown in FIG. 3, this chamber device is connected to a wafer 22, a rotation shaft 30 of a rotation drive mechanism that supports the wafer 22 and a motor in a chamber 21, and is rotatable integrally with the wafer 22, as shown in FIG. There is provided a spin coating apparatus including a wafer chuck 23, at least a wafer 22, a spin cup 24 surrounding the wafer chuck 23, and the like. Wafer 22
Is rotated, the application liquid supplied to the central portion of the wafer 22 is applied, and a coating film is formed. The thickness of the coating film is easily controlled according to the number of rotations of the rotation drive mechanism.

The side of the chamber 21 has a wafer inlet 27 and a wafer outlet
28 are provided. The wafer 22 is inserted from a wafer inlet 27, subjected to a coating process, and taken out from a wafer outlet 28.

Further, an air supply duct 25 is provided in an upper part of the chamber 21. Although the air supplied from the air supply duct 25 is subjected to temperature and humidity control in advance, it is further purified by an air filter 29 and supplied into the chamber 21. On the other hand, air containing droplets of the coating liquid and solvent vapor is forcibly discharged from an exhaust duct 26 provided at a lower portion of the chamber 21.

[Problems to be solved by the invention]

By the way, in a semiconductor device with high integration, improvement in thickness accuracy of a resist film has become a major issue as a pattern becomes finer.

In order to form a resist film having a uniform thickness using the above-described chamber apparatus for a spin coating apparatus, a coating liquid is supplied onto the wafer from a state immediately before the coating liquid is supplied onto the wafer, and further, a desired film is formed. It is necessary to minimize the change in the viscosity of the coating liquid throughout the process until the coating liquid is formed. Various methods can be considered as means for suppressing a change in the viscosity of the coating liquid. However, it is necessary to stabilize the airflow around the wafer and the ambient temperature during film formation.

Specifically, in a chamber apparatus for a spin coating apparatus as shown in FIG. 3, the supply amount of air supplied from the air supply duct 25 and the exhaust amount of gas exhausted from the exhaust duct 26 are determined. It is necessary to keep a balance. Actually, even if the wafer is simply rotated, the balance is lost. Therefore, it is extremely difficult to control the supply amount and the exhaust amount equally in the related art.

For example, when the supply amount of air supplied from the air supply duct 25 becomes smaller than the exhaust amount discharged from the exhaust duct 26,
Air A whose temperature and humidity are not controlled from the outside is taken into the spin cup 24 from the wafer inlet 27 and the wafer outlet 28, so that a resist film having a uniform film thickness cannot be obtained.

Conversely, when the supply amount of the supply air becomes larger than the exhaust amount, the gas B generated in the spin cup 24 due to the evaporation of the solvent of the coating liquid diffuses into the chamber 21 and passes through the wafer inlet 27 and the wafer outlet 28. It is discharged outside. As a solvent for the resist, a substance harmful to the human body, such as ethyl cellosolve acetate, is often used.

Therefore, the present invention has been proposed in view of such a conventional situation, and prevents a change in the film thickness of a coating film due to a disturbance in a balance between an air supply amount and an exhaust amount, and provides spin coating with excellent safety. An object of the present invention is to provide a chamber apparatus for an apparatus and a method for forming a coating film capable of forming a coating film such as a resist film having a uniform film thickness on the surface of a wafer while suppressing a variation in the film thickness of the coating film. It is a proposal.

[Means for solving the problem]

In order to achieve the above object, a chamber apparatus for a spin coating apparatus according to the present invention includes a chamber surrounding the spin coating apparatus, an air supply duct for introducing air into the chamber, A first exhaust duct for exhausting the air, a wafer insertion port provided in the chamber for inserting a wafer supported by the spin coating device into the chamber, and a wafer insertion port supported by the spin coating device. A wafer take-out port provided in the chamber for taking out a wafer to be taken out of the chamber, and an exhaust port provided along a wall of the chamber with opening ends facing the wafer insertion port and the wafer take-out port, respectively. And a second exhaust duct connected to the means.

Further, in the method for forming a coating film according to the present invention using the chamber device, air is supplied from an air supply duct into a chamber surrounding the pin coating device, and the inside of the chamber is forced through a first exhaust duct. The second exhaust duct is provided along the wall of the chamber with the opening ends facing the wafer insertion port and the wafer removal port provided in the chamber, and the inside of the second exhaust duct is forcibly exhausted by exhaust means. Thus, a coating film such as a resist film is applied to the surface of the wafer while rotating the wafer supported by the spin device.

[Action]

The chamber apparatus for a spin coating apparatus according to the present invention is configured such that, when the supply amount of air supplied from the air supply duct becomes smaller than the exhaust amount discharged from the exhaust duct, the second exhaust duct connected to the exhaust unit. Is suctioned and evacuated, the intrusion of external air that is not temperature and humidity controlled from the wafer entrance and exit is trapped, discharged through the second exhaust duct, and the air in the chamber can be shut off from the outside. The atmosphere in the chamber is stabilized.

In addition, the supply amount of air supplied from the air supply duct is the first.
If the amount of exhaust gas discharged from the exhaust duct is larger than that of the chamber, the harmful gas generated by evaporation of the solvent of the coating solution is discharged through the second exhaust duct even if it tries to flow out of the wafer inlet / outlet. Is prevented from being diffused and flowing out.

In the spin coating apparatus, with respect to a technique for generating a local airflow, for example, there are those disclosed in JP-A-62-71567 and JP-A-62-164976,
Each of these aims to prevent the application liquid from scattering by generating a downstream gas near the outer peripheral portion of the rotating substrate, and has a different purpose and effect from the present invention.

Further, in the coating film forming method according to the present invention, the inside of the second exhaust duct is provided along the wall of the chamber with the opening ends facing the wafer insertion port and the wafer removal port provided in the chamber. By applying a coating film on the surface of the wafer while rotating the wafer supported by the spin device in a state of forcibly evacuated by the means, the air in the chamber is shut off from the outside, the atmosphere in the chamber is stabilized, The gas in the chamber is prevented from flowing out of the wafer port.

〔Example〕

A specific embodiment of a chamber apparatus for a spin coating apparatus according to the present invention and a method for forming a coating film for applying a resist film on the surface of a wafer using the chamber apparatus will be described with reference to the drawings.

First Embodiment This embodiment is an example in which the present invention is applied to a resist coating apparatus and a second exhaust duct serving as an airflow control duct is provided along the outer wall of the chamber.

In the chamber apparatus, a spin cup 4 surrounding a wafer 2 and a wafer chuck 3 is provided inside a chamber 1 as shown in FIG. The wafer 2 is supported by a wafer chuck 3. The wafer chuck 3 is connected to a rotation shaft 13 of a rotation drive mechanism such as a motor so that the wafer chuck 3 can rotate integrally with the wafer 2. The rotation of the rotation drive mechanism applies the resist liquid supplied to the central portion of the wafer 2 by a resist liquid supply mechanism (not shown). At this time, the thickness of the resist film is easily controlled according to the rotation speed of the rotation drive mechanism.

A wafer inlet 7 is provided on one side of the chamber 1 and a wafer outlet 8 is provided on the other side. The wafer 2 is inserted into the chamber 1 from the wafer inlet 7 and is taken out from the wafer outlet 8 through the coating process.

An air supply duct 5 for introducing air of which temperature and humidity are controlled in advance into the chamber 1 is provided at an upper portion of the chamber 1. The air supplied from the air supply duct 5 is filtered by a filter 9.
And diffuses into the chamber 1. on the other hand,
Air containing resist liquid droplets, solvent vapor, etc.
Is forcibly discharged to the outside from a first exhaust duct 6 provided at a lower part of the first exhaust duct.

Further, the second exhaust duct 10 extends along the outer wall of the chamber 1.
a is provided. The second exhaust duct 10a is opened immediately below the wafer inlet 7 and the wafer outlet 8, and the lower portion is connected to an exhaust unit (not shown). In such a second exhaust duct 10a, the exhaust means is driven to exhaust the inside of the pipe, so that a downward airflow is forcibly generated near the opening and in the pipe.

As described above, since the second exhaust duct 10a is connected to the wafer inlet 7 and the wafer outlet 8, the amount of air exhausted through the above-described first exhaust duct 6 and the amount of air exhausted through the air supply duct 5 are increased. In the case where the supply amount of the supplied air is out of balance and the exhaust amount exceeds the supply amount, the external air that is going to enter from the wafer inlet 7 or the wafer outlet 8 is trapped in the second exhaust duct 10a. You. That is, outside air whose temperature and humidity are not adjusted is prevented from entering the chamber 1 and is discharged through the second exhaust duct 10a. Therefore, the coating process of the resist solution supplied to the surface of the wafer 2 supported by the wafer chuck 3 can be performed in a stable atmosphere, and the variation in the thickness of the resist film due to the change in the viscosity of the resist solution can be prevented. A coating film having an appropriate thickness is formed.

In addition, when the above-described air supply amount exceeds the exhaust amount,
Even if the evaporation solvent of the coating solution diffuses into the chamber 1 and tries to flow out through the wafer inlet 7 and the wafer outlet 8, it is discharged from the second exhaust duct 10a. Therefore, there is no possibility that the harmful gas is exhausted to the outside of the chamber 1, so that the problem of safety and health is improved.

Further, in this embodiment, the second exhaust duct 10a is disposed along the outer wall of the existing chamber 1, but the second exhaust duct 10a extends along the inner wall of the chamber 1 as shown by a dotted line in FIG. 10b may be provided.

Second Embodiment This embodiment is an example in which a second air supply duct is further provided on the outer wall of the chamber shown in the above-described first embodiment to enhance the airflow control effect. This will be described with reference to FIG. In this embodiment, the same parts as those in the first embodiment will be described using the same reference numerals.

In this chamber apparatus, an auxiliary air supply duct 12 is provided along the outer wall of the chamber 1 as shown in FIG. The auxiliary air supply duct 12 is provided above the openings of the wafer inlet 7 and the wafer outlet 8. Air is supplied to the auxiliary air supply duct 12 from air supply means (not shown). This air does not need to be particularly temperature and humidity controlled.

Further, a second exhaust duct 11 is provided below the auxiliary air supply duct 12.
Are disposed opposite to each other. The second exhaust duct 11 is opened immediately below the wafer inlet 7 and the wafer outlet 8, and the lower portion is connected to an exhaust unit (not shown). Such a second
In the exhaust duct 11, the exhaust means is driven to exhaust the inside of the pipe, so that a downward airflow is forcibly generated near the opening and in the pipe.

By sending gas into the auxiliary air supply duct 12 in this manner, a high-speed airflow can be generated near the wafer inlet 7 and the wafer outlet 8 without disturbing the air in the chamber 1. Therefore, even if the balance between the exhaust amount and the supply amount of air into the chamber 1 is lost, the wafer chuck 3
The coating process of the resist solution supplied to the surface of the wafer 2 supported on the substrate can be performed in a stable atmosphere, and the resist film thickness variation due to the change in the viscosity of the resist solution and the like can be prevented, and the coating with a uniform film thickness can be performed. A film is formed.

[Effects of the Invention] As described above, in the chamber apparatus for a spin coating apparatus according to the present invention and the method for forming a coating film on the surface of a wafer using the chamber apparatus, the supply of air in the chamber is Even if the balance between the volume and the exhaust volume is lost, the atmosphere in the chamber can be kept constant, so that the fluctuation of the film thickness of the coating film applied on the surface of the wafer can be suppressed and the reliability is excellent. It becomes possible to form a coated film.

Further, since there is no possibility that harmful solvent vapor leaks to the outside, it is possible to form a coating film excellent in safety.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of a chamber apparatus for a spin coating apparatus according to the present invention, and FIG.
It is a schematic sectional drawing of the Example of FIG. FIG. 3 is a schematic sectional view showing a conventional chamber apparatus for a spin coating apparatus. 1 ... chamber, 2 ... wafer, 3 ... wafer chuck, 4 ... spin cup, 5 ... air supply duct, 6 ... first exhaust duct, 7 ... wafer inlet, 8 ... wafer outlet, 9 ... air filter, 10a, 10b, 11 ... second exhaust duct, 12 ... auxiliary air supply duct.

Claims (2)

(57) [Claims] 1. A chamber surrounding a spin coating device, an air supply duct for introducing air into the chamber, a first exhaust duct for exhausting air from the chamber, and the spin coating device. A wafer insertion port provided in the chamber for inserting a wafer supported in the chamber into the chamber; and a wafer removal provided in the chamber for removing a wafer supported by the spin coating device from the chamber. And a second exhaust duct provided along the wall of the chamber with opening ends facing the wafer insertion opening and the wafer removal opening, respectively, and a second exhaust duct connected to an exhaust unit. Chamber equipment. 2. A method according to claim 1, further comprising: supplying air from a supply duct into a chamber surrounding the spin coating apparatus, forcibly exhausting the chamber through a first exhaust duct, and further comprising a wafer provided in the chamber. The wafer supported by the spin device is rotated while the second exhaust duct provided along the wall of the chamber is forcibly evacuated by an evacuation means with the opening ends facing the insertion port and the wafer ejection port, respectively. A coating film forming method for applying a coating liquid to the surface of the wafer while the coating is performed.