JP2002110522A - Rotary application device and film formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary application device and a film formation method for uniformly forming a resist film on a substrate, especially, on a square substrate. SOLUTION: This rotary application device has a rotary cup 1 that has an exhausting port 5 that can be rotated with a center shaft as a center, has an open upper section 4, and discharges gas flowing in from the open upper section 4, and retains the substrate S inside while the upper surface becomes vertical to the center shaft, a breathing filter 23 that can block the opening section 4, a lid 25 that is arranged on the filter 23 and does not have any permeability, and an interval adjustment mechanism that can adjust the interval between the filter 23 and the upper surface of the substrate S retained in the rotary cup 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a technique for forming a film such as a resist film, and more particularly, to a spin coating apparatus and a film forming method suitable for forming a film on a rectangular substrate such as a photomask or a reticle.

[0002]

2. Description of the Related Art With the recent increase in the degree of integration of semiconductor devices, there has been a demand for higher dimensional accuracy and higher appearance quality of patterns formed on photomasks and reticles serving as masters for pattern formation. .

In particular, as the size of a semiconductor substrate has increased, the size of a photomask and a reticle have also increased, and it has been necessary to maintain dimensional accuracy and quality in a wider range. A resist film on a square mask blank substrate (a thin glass substrate coated with a reflective film such as chromium, for example, hereinafter simply referred to as a square substrate or simply a substrate) used in manufacturing a photomask or a reticle. Is formed, and the resist film is patterned to form a mask pattern. The reflection film is etched using the mask pattern as an etching mask. Variations in the thickness of the resist film are one cause of an error in the pattern size of the reflective film.

If the thickness of the resist film varies on the substrate surface, even if a resist pattern having the same dimensions is formed, the dimensions are difficult to be uniform on the substrate surface. In particular, when a resist film is formed on a rectangular substrate, there has been a problem that the resist is preferentially dried and solidified at the four corners of the rectangular substrate, and the resist film at the four corners becomes too thick.

After a coating solution is dropped on the surface of the square substrate,
A method of drying a resist film by rotating a rectangular substrate in a closed space has also been proposed. When the resist film is dried while forming a closed space and rotating, the air in the closed space also rotates together with the substrate.
The solvent contained in the coating solution evaporates and fills the enclosed space, and has an appropriate partial pressure. Thereby, the evaporation rate of the solvent remaining in the resist film, that is, the drying rate can be adjusted appropriately, and the problem that the film thickness becomes too large at the four corners of the rectangular substrate can be solved.

[0006]

However, when the above-mentioned method is used, when a closed space is opened, the vapor of the solvent filled in the space rapidly diffuses into the atmosphere, and the resist film is rapidly formed. Will dry out. With the rapid drying of the resist film, a new problem arises in that a mottled pattern is formed on the surface of the rectangular substrate.

To solve the above-mentioned problem caused by rapid drying of the resist film accompanying opening from the closed state, it has been proposed to solve the above-mentioned problem by Japanese Patent Application Laid-Open No. 11-188304. It is a device.

FIG. 9A is a sectional view showing the structure of a spin coating apparatus devised by the inventor of the present application and disclosed in Japanese Patent Application Laid-Open No. H11-188304.

The spin coating device X includes a spin cup 101,
A driving unit 111 for rotating the rotating cup 101;
Rotating hood 121 mounted on rotating cup 101
And an exhaust hood 131 surrounding the rotating cup 101 and the rotating hood 121.

The rotating cup 101 comprises a cup 103b,
And a stage 103a. Cup 103
b has a disk-shaped bottom surface and a cylindrical side surface. The upper part of the cup 103b is opened, and an opening 104 is defined.

[0011] A plurality of outlets 105 are provided on the side of the cup 103b. Stage 103a is cup 1
03b, it is arranged substantially parallel to the bottom surface. The height from the bottom surface to the upper surface of the stage 103b is substantially equal to the height from the bottom surface to the center of the discharge port 105.

The driving section 111 has a spin motor 113 and a rotating shaft 115. The center of the lower surface of the stage 103a is fixed to the rotating shaft 115. Rotating shaft 115
Rotates, the stage 103a and the cup 103b rotate.

The rotary hood 121 includes a gas permeable filter 123 capable of closing the opening 104, a gas permeable lid 125 laid on the filter 123, and a lid 12.
5 has a holding portion 127 attached to the upper surface thereof. The rotating hood 121 is the opening 104 of the cup 103b.
When the rotating cup 101 is rotated in a state in which is closed, the rotating hood 121 also rotates.

The exhaust hood 131 is a rotating cup 101.
Hood 133 provided to surround the outer periphery of
And an exhaust port 135 following the hood 133. The exhaust port 135 also serves as a waste liquid port.

A procedure for forming a resist film on the substrate S using the apparatus shown in FIG. 9A will be described.

First, the substrate S is placed on the stage 103a, and a coating liquid R1 for forming a resist film is dropped.

The opening 104 of the rotating cup 101 is closed by the rotating hood 121 in which the filter 123 and the lid 125 are overlapped. The rotating cup 101 is rotated at a high speed to adjust the resist film thickness.

The rotation of the rotating cup 101 is temporarily stopped, and only the lid 125 is removed. The opening 104 is a filter 123
The rotation cup 101 is rotated at a low speed in a state where the resist film is closed by only the above, and the resist film is dried.

Observation of the surface of the resist film applied using the above-described resist film coating apparatus X revealed that in-plane variation in the thickness of the resist film occurred.

FIG. 1B shows the state of the surface of the resist film formed on the substrate. As shown in FIG.
A mesh-like pattern 151 having an interval of about m was observed. This pattern 151 is caused by the in-plane variation of the thickness of the resist film.

An object of the present invention is to form a resist film uniformly on a substrate, particularly on a square substrate.

[0022]

According to one aspect of the present invention, there is provided an outlet which is rotatable about a central axis, is open at an upper side, and discharges gas flowing in from an upper opening. A rotating cup for holding the substrate inside such that the upper surface thereof is perpendicular to the central axis, a gas-permeable filter capable of closing the opening, and a gas-permeable filter disposed on the filter. There is provided a spin coating apparatus having a cover having no property, a filter, and a gap adjusting mechanism capable of adjusting a gap between the filter and an upper surface of a substrate held in the rotating cup.

If the open portion is covered with a non-breathable lid, the flow of gas from the open portion to the discharge port is shut off. When the substrate is rotated in this state, the gas in the rotating cup rotates at substantially the same rotational angular velocity as the substrate. If the lid is removed and the opening is covered with only a gas-permeable filter, a certain amount of gas flows in the rotating cup, and the drying speed of the membrane can be adjusted.

The distance adjusting mechanism can adjust the distance between the substrate and the filter so that the mesh pattern of the filter is not transferred to the surface of the substrate.

According to another aspect of the present invention, the substrate is rotatable about a central axis, has an upper opening, and has an outlet through which gas introduced from the upper opening is discharged.
A rotating cup that holds the inside thereof so that its upper surface is perpendicular to the central axis, a gas-permeable filter that can close the opening, and a gas-impermeable lid that is disposed on the filter. Wherein the permeation flow rate in the first region above the substrate held in the rotating cup is smaller than the permeation flow rate in the second region around the first region. Is provided.

Since the gas permeation flow rate in the first region above the substrate is small, the pattern of the filter is not easily transferred to the surface of the film. Since the permeation flow rate of the gas in the surrounding second region is large, the overall air permeability is appropriately maintained,
It is possible to prevent the drying speed of the film from excessively decreasing.

According to another aspect of the present invention, (a) a step of holding the substrate in a rotating cup having an upper opening and having an outlet through which gas flowing in from the upper opening is discharged; A) a step of dropping a coating liquid for forming a film on the surface of the substrate; and (c) a step of covering the opening with a gas-permeable filter and a gas-impermeable lid overlying the filter. (D) forming a film covering the surface of the substrate by rotating the rotating cup at a first angular velocity with the distance between the filter and the surface of the substrate as a first distance; e) removing the lid from above the filter without removing the filter from the rotating cup, and adjusting the distance between the filter and the surface of the substrate to the first position;
And drying the film by rotating the rotating cup at a second angular velocity lower than the first angular velocity.

According to yet another aspect of the present invention, (a)
A step of holding the substrate in a rotating cup having an upper opening and having an outlet through which gas flowing from the upper opening is discharged, and (b) dripping a coating liquid for forming a film on the surface of the substrate (C) a filter having a lower permeation flow rate in a first area above the substrate held by the rotating cup than a permeation flow rate in a second area surrounding the first area;
Covering the open portion with a non-breathable lid overlying the filter; and (d) rotating the rotating cup at a first angular velocity to form a film covering the surface of the substrate. And (e) removing the lid from above the filter without removing the filter from the rotating cup, and rotating the rotating cup at a second angular velocity smaller than the first angular velocity to dry the film. And a film forming method.

The distance between the substrate surface and the filter can be adjusted to respective optimum values in the substrate rotation step mainly for adjusting the film thickness and the substrate rotation step mainly for drying the film.

In the substrate rotation process whose main purpose is to adjust the film thickness, the filter is covered with a lid, and the inside of the rotary cup is made substantially non-permeable. The air in the rotating cup rotates with the substrate. The spacing between the substrate surface and the filter is such that the film can be prevented from preferentially solidifying at the four corners of the square substrate.

In the substrate rotation process whose main purpose is to dry the film, the lid on the filter is removed to provide air permeability. The distance between the substrate surface and the filter is adjusted to be different from the distance in the substrate rotation step mainly for adjusting the film thickness. In the substrate rotation process whose main purpose is to dry the film, the distance between the substrate surface and the filter is maintained such that the mesh pattern of the filter does not transfer to the surface of the film.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The inventor of the present invention has found that the mesh pattern shown in FIG. 9 (B) is formed because the mesh pattern formed on the filter has a resist pattern in a process for drying the resist film. It is considered that this is because the film is transferred to the film and a distribution occurs in the thickness of the resist film. When the air passes through the filter, the flow velocity of the air differs between the opening and the non-opening of the filter, and a flow velocity distribution occurs in the air. This flow velocity distribution also affects the flow velocity distribution of air on the resist film,
As a result, it is considered that there is a difference in the air drying rate in the plane.

The inventor of the present invention has set the distance between the substrate surface and the filter in the substrate rotation step mainly for drying the resist film to be different from the distance in the substrate rotation step mainly for the adjustment of the resist film thickness. I thought about adjusting. In the substrate rotation process whose main purpose is to dry the resist film, the distance between the substrate and the filter may be maintained such that the mesh pattern of the filter is not transferred to the resist film on the substrate.

Hereinafter, a film forming technique according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1A is a sectional view showing the structure of a spin coating apparatus according to a first embodiment of the present invention.

The rotary coating apparatus A for forming a resist film includes a rotary cup 1, a driving unit 11 for rotating the rotary cup 1, and a rotary hood 2 mounted on the rotary cup 1.
1 and an exhaust hood 31 surrounding the rotating cup 1.

FIG. 1B is a perspective view showing the structure of the rotating cup 1 in detail.

The rotary cup 1 comprises a cup 3b and a stage 3a. The cup 3b has a disk-shaped bottom surface and a cylindrical side surface. The upper part of the cup 3b is opened, and an opening 4 is defined.

A plurality of outlets 5 are provided on the side of the cup 3b. The stage 3a is provided in the cup 3b, and is arranged substantially parallel to the bottom surface thereof. The height from the bottom surface to the upper surface of the stage 3a is substantially equal to the height from the bottom surface to the center of the discharge port 5. The discharge port 5 has an opening 5a provided on a side surface and a cylindrical protrusion 5b protruding outward with the opening 5a as a base end. By forcibly exhausting the gas to a pressure of ₂₀ mmH ₂ O to 40 mmH ₂ O using an exhaust pump or the like, the gas flowing from the opening 4 is exhausted from the exhaust port 5.

The stage 3a is provided with a mechanism for mechanically holding the rectangular substrate S. For example, the substrate S can be fixed to the stage 3a by being supported at eight points by a mechanical chuck.

The exhaust hood 31 has a hood section 33 and an exhaust port 35. The hood part 33 is a rotating cup 1
When the rotating hood 21 is placed on the outside, both are surrounded from the outside.

The drive section 11 has a spin motor 13 and a rotating shaft 15. The rotation shaft 15 is fixed to the center of the lower surface of the stage 3a. When the rotating cup 1 is rotated around the rotating shaft 15 as a center axis, the stage 3a and the cup 3 are rotated.
b rotates. By using the spin motor 13, the rotating cup 1 can be rotated at a desired rotation speed from low-speed rotation to high-speed rotation. The rectangular substrate S is held in the rotating cup 1 such that the upper surface thereof is perpendicular to the central axis.

With reference to FIGS. 2A to 2D, the structure of the rotating hood and steps for attaching and detaching the rotating hood to and from the rotating cup will be described. FIG. 2A shows a state in which the rotating hood 21 is mounted on the rotating cup 1.
FIG. 2B is a plan view of the rotating hood.

As shown in FIGS. 2A and 2B,
The rotating hood 21 has a filter frame 22, a permeable filter 23, a non-permeable lid 25, a grip 27, a handle T, and a leg 29.

The filter frame 22 is formed, for example, in a ring shape. A handle T is formed on the upper surface of the filter frame 22. The filter 23 has air permeability,
The inside of the opening of the filter frame 22 is almost covered. The lid 25 also has a substantially circular shape according to the shape of the opening of the filter frame 22. A grip portion 27 is formed on the upper surface of the lid 25.

As a material for the filter 23, for example, S
A US-made wire mesh sintered porous plate is used. The permeation flow rate is
It is 3.9 cc / cm ² · mmH ₂ O · min.

Unit: cc / cm ² · mmH ₂ O · min
Is the flow rate of gas flowing per cm ^{2 of} the perforated plate in a unit of cc / min when the pressure difference between both surfaces of the perforated plate is 1 mmH ₂ O. Pressure 1mmH ₂ O
Is 9.807 Pa.

When the lid 25 is placed on the filter frame 22 placed on the rotating cup 1, the air permeability held by the filter 23 is blocked by the lid 25.

The manner in which the rotary hood 21 is removed from the state in which the rotary hood 21 is placed on the rotary cup 1 as shown in FIG. 2 (A) will be described with reference to FIGS. 2 (C) and 2 (D). I do.

As shown in FIG. 2C, when the user lifts the holding portion 27 upward, the lid 25 separates from the filter frame portion 22. Only the lid 25 can be removed from the rotating cup 1. That is, the filter frame portion 22 and the filter 23
Can be left on the rotating cup 1 and only the lid 25 can be removed. In this state, the air permeability in the rotating cup 1 is maintained by the filter 23.

When the filter frame portion 22 is lifted with the handle T in a state where the lid 25 is mounted on the filter 23, the filter 23 and the filter frame portion 22 are brought into contact with the lid 25 as shown in FIG. Can be lifted together.

The lifting mechanism 28 which can lift the filter frame 22 together with the filter 23 and the lid 25 by holding only the grip 25 and the lid 25 together with the handle T (FIG. 1). (A), only the lid 25 or the lid 25 and the filter 23 can be raised and lowered integrally by the lifting mechanism 28.

The procedure for forming a resist film on the substrate S using the apparatus shown in FIG. 1 will be described with reference to FIGS. 3A to 4D.

As a substrate, 152.0 mm × 152.0
A chrome substrate (mask blanks: a substrate formed by depositing chromium on quartz glass; hereinafter, referred to as a rectangular substrate or simply a substrate) having a thickness of 6 mm (6 inch square) was used. The thickness of the substrate is 6.35 mm (0.25 inch).

The leg 29 is provided on the lower surface of the filter frame 22.
Installed. By mounting the legs 29 on the protrusions 5b, the rotary hood 21 can be rotated integrally with the rotary cup 1.

As shown in FIG. 3A, first, the substrate S is placed on the stage 3a, and a coating solution for forming a resist film is formed.
For example, a novolak coating liquid is dropped on the surface of the substrate S. In order to supply the coating liquid onto the substrate, for example, a resist coating liquid supply device C is provided outside the rotating cup 1. The resist coating liquid supply device C has a movable nozzle arm, and the coating liquid can be dropped on the substrate by moving the nozzle arm. After the application liquid is dropped, the nozzle arm returns to the standby position outside the rotating cup 1.

As shown in FIG. 3B, with the lid 25 overlaid on the filter 23, the leg 29 is placed on the protrusion 5b of the discharge port 5. The opening 4 is closed. In this state, the height of the leg 29 is set such that the distance between the upper surface of the substrate S and the lower surface of the filter 23 is a predetermined distance (first distance).

In this state, the substrate S placed on the rotating cup 1 is rotated at, for example, 2500 revolutions / minute for 10 minutes.
Spin at high speed for seconds. Resist film R on the surface of substrate S
2 are formed.

As shown in FIG. 4C, after the rotation of the rotating cup 1 is stopped, the lid 25 is removed from the rotating cup 1 by grasping the grip portion 27 and lifting it up. A spacer 37 having a predetermined height is inserted between the lower end of the leg 29 and the upper surface of the protrusion 5b. The distance between the upper surface of the substrate S and the lower surface of the filter 23 is longer than the first distance by the height of the spacer 37. This distance is called a second distance.

When it is desired to make the second distance shorter than the first distance, for example, the length of the leg 29 may be shortened.

As shown in Table 1, the value of (second distance / first distance) (hereinafter referred to as an interval ratio) is 0.4,
Experiments were performed under four conditions of 1.0, 1.4, and 2.1. The case where the interval ratio is 1.0 means that the distance between the upper surface of the substrate and the lower surface of the filter is not changed between the film thickness adjusting step and the film drying step.

The resist film drying step was performed under the conditions of each interval ratio. The substrate rotation speed in this step is 50 rotations per minute, and the rotation time is 180 seconds.

As shown in FIG. 4D, the rotation of the substrate S is stopped, and the filter 23 is removed from the rotating cup 1. Next, the substrate S is taken out of the rotating cup 1.

[0064]

[Table 1]

Table 1 shows that the interval ratio was 0.4, 1.0, 1.4.
The results of evaluation of the film thickness distribution of a resist film formed under the same conditions as those of the first embodiment except that the conditions are 2.1 and 2.1 are shown. The measurement area is one side
This is a 32 mm square area. The measurement points are 169 points (13 × 13).

For the interval ratios of 0.4, 1.0, 1.4 and 2.1, respectively, the value obtained by dividing the difference between the maximum value and the minimum value of the film thickness by the average value of the film thickness, and 3σ And the value obtained by dividing the value by the average value is shown as a percentage.

It was found that as the interval ratio increased, the value obtained by dividing the difference between the maximum value and the minimum value of the film thickness by the average value of the film thickness and the value obtained by dividing the value of 3σ by the average value became smaller. At least up to the interval ratio of 2.1, the greater the interval ratio, the smaller the in-plane variation of the resist film thickness.

When the interval ratio is increased to about 2.1, it becomes difficult to transfer the filter mesh pattern onto the surface of the resist film.

When the film forming technique according to the first embodiment is used, the mesh pattern of the filter is not transferred to the surface of the resist film by increasing the distance between the filter and the substrate surface during the resist film drying step.

Next, a technique for forming a resist film according to a second embodiment of the present invention will be described with reference to FIGS.

FIG. 5 is a sectional view showing the structure of the spin coating apparatus. The device shown in FIG. 5 and the device shown in FIG.
They have almost the same structure. The device shown in FIG. 5 and FIG.
The difference from the device shown in (A) is the structure of the filter 23 and the structure of the legs 29 (FIG. 1A).

The filter 23 shown in FIG. 5 includes a low-permeability area 23a having a small gas permeation flow rate (low air permeability) and a high-permeability area 23b having a larger gas permeation flow rate (high air permeability). And Low air permeability area 23a
Are formed in a region (first region) above the substrate S placed on the rotating cup 1. Highly permeable region 23b
Are formed in a second region around the first region.
The area of the first region may be slightly larger than the area of the substrate. In this embodiment, the area of the first region is, for example, 152 m.
mx 152 mm.

As the filter 23, a wire mesh sintered porous plate made of SUS is used. The permeation flow rate of the low permeability filter is
2.0, 3.9, 7.8 and 20 cc / cm ² · mmH ₂
Four filters of O · min were prepared. The permeation flow rate of the highly permeable region 23b is 20 cc / cm ² · mmH ₂ O ·
min.

With reference to FIGS. 6A to 7D, a procedure for applying a resist film R on the substrate S using the apparatus shown in FIG. 5 will be described.

As a substrate, 152.0 mm × 152.0 mm
A square substrate of mm (6 inches square) was used. The thickness of the substrate is 6.35 mm (0.25 inch).

As shown in FIG. 6A, first, the substrate S is placed on the stage 3a, and a coating solution for forming a resist film is formed.
For example, a novolak coating liquid is dropped on the surface of the substrate S.

As shown in FIG. 6B, the filter frame 22 is placed on the cup 3 with the lid 25 placed on the filter 23.
b. The opening 4 is closed and the air permeability is lost. The distance between the upper surface of the substrate S and the lower surface of the filter 23 is set to be a predetermined distance (first distance).

In this state, the substrate S placed on the rotary cup 1 is rotated at a rotation speed of 2500 revolutions / minute for 10
Spin at high speed for seconds. Resist film R on the surface of substrate S
2 are formed.

As shown in FIG. 7C, the rotating cup 1
After stopping the rotation of the (substrate S), the rotation cup 1
Remove only. Next, a resist film drying step is performed.
The substrate rotation speed in this step is 50 rotations per minute,
The rotation time is 180 seconds.

As shown in FIG. 7D, the rotation of the substrate S is stopped, and the filter 23 is removed from the rotating cup 1. Next, the substrate S is taken out of the rotating cup 1.

[0081]

[Table 2]

Table 2 shows the relationship between the gas permeation flow rate and the in-plane variation of the resist film thickness in the low air permeability region when the resist film is formed by using the resist film forming technique according to the second embodiment. .

As shown in Table 2, the permeation flow rate at least in the low air permeability region was 2.0 to 20 cc / cm ² · m.
It was found that in the range of mH ₂ O · min, the smaller the transmission flow rate in the low air permeability region, the smaller the in-plane variation of the resist film thickness. Permeation flow rate is 2.0cc / cm ²・ m
At mH ₂ O · min, a small variation value almost the same as the value of the in-plane variation of the resist film in Table 1 (the value in the case of the interval ratio of 2.1) was obtained.

By drying the resist film by lowering the permeation flow rate of the filter in the first area above the substrate than the permeation flow rate in the surrounding second area, the air permeability in the rotary cup 1 as a whole is reduced. While maintaining a substantially constant value, the in-plane variation of the resist film thickness due to the difference in air permeability between the opening and the non-opening of the filter can be reduced. By increasing the transmission flow rate of the filter on the second region, a decrease in the resist drying speed is prevented, and an increase in the thickness of the resist film at the four corners of the square substrate caused by the resist drying speed becoming too slow is prevented. Can be prevented. A resist film with small thickness variation can be formed.

FIG. 8 shows a modification of the spin coating apparatus according to the second embodiment. The spin coating device shown in FIG. 8 has substantially the same structure as the spin coating device shown in FIG. In order to arrange a low-permeability area having a small permeation flow rate in an area above the substrate, a normal filter (hereinafter referred to as main filter 23c) is used.
Call. ) Is overlapped with the same filter or a different filter (hereinafter referred to as a sub-filter 24). When the main filter 23c and the sub-filter 24 are combined, the number of filters to be overlapped may be two or more.

A protrusion is formed on the main filter 23c by the thickness of the sub-filter 24. A recess 26 may be formed on the lower surface of the lid 25 so as to easily accommodate the protrusion.

Also in the case of using the apparatus shown in FIG. 8, the resist film is formed by using the same method as the resist film forming method described in the second embodiment, so that the in-plane thickness of the resist film can be reduced. Variation can be reduced.

As explained above, the first and the second
When the film forming technique according to the embodiment is used, it is possible to reduce the variation in the thickness of the resist film in the substrate surface, particularly the variation due to the transfer of the filter pattern generated in the resist film drying step.

In the above embodiment, a rectangular substrate for a photomask has been described as an example of the substrate. However, the photolithography technique is applied to other rectangular substrates, for example, a rectangular substrate for forming a liquid crystal device. In this case, the present invention can be applied to a resist film forming technique.

The present invention has been described in connection with the preferred embodiments.
The present invention is not limited to these. It will be apparent to those skilled in the art that various other modifications, improvements, and combinations are possible.

The present specification includes the inventions described in the claims and the inventions described below.

(Supplementary Note 1) The substrate is rotatable about a central axis, has an upper opening, and has an outlet through which gas flowing in from the upper opening is discharged. A rotating cup that is held inside so as to be perpendicular to the inside, a gas-permeable filter that can close the opening, a gas-impermeable lid placed on the filter, the filter, A spin coating device having an interval adjusting mechanism capable of adjusting an interval between the substrate and an upper surface held in the spin cup. (1) (Supplementary note 2) The supplementary note 1 having an elevating mechanism capable of lifting only the lid or lifting both the lid and the filter from the state where the lid and the filter cover the opening. Spin coating device. (2) (Supplementary note 3) The rotary coating apparatus according to Supplementary note 1 or 2, further comprising a coating liquid supply device capable of dropping a coating liquid for film formation on the substrate held by the rotating cup. . (3) (Supplementary note 4) The spin coating device according to any one of Supplementary notes 1 to 3, wherein the gap adjusting unit is a spacer interposed between the filter and the rotating cup.

(Supplementary Note 5) The substrate is rotatable about a central axis, has an upper opening, and has an outlet through which gas flowing in from the upper opening is discharged. A rotating cup that is held inside so as to be perpendicular to the inside, a gas-permeable filter that can close the opening, and a gas-impermeable lid that is placed on the filter. A rotary coating device in which a permeation flow rate in a first area above a substrate held in the rotation cup is smaller than a permeation flow rate in a second area around the first area; (4) (Supplementary Note 6) The supplementary note 5, wherein the filter is formed by a main filter having uniform air permeability in all regions, and a sub-filter superimposed on the first region of the main filter. Spin coating device.

(Supplementary Note 7) (a) a step of holding the substrate in a rotating cup having an upper opening and having an outlet through which gas flowing in from the upper opening is discharged; A step of dropping a coating solution for film formation on the
(C) covering the opening with a gas-permeable filter and a gas-impermeable lid overlying the filter;
(D) forming a film covering the surface of the substrate by rotating the rotating cup at a first angular velocity with the distance between the filter and the surface of the substrate being a first distance;
(E) removing the lid from above the filter without removing the filter from the rotating cup, and changing an interval between the filter and the surface of the substrate to a second interval different from the first interval; The rotating cup is connected to the first
Rotating the film at a second angular velocity lower than the angular velocity to dry the film. (5) (Supplementary Note 8) The film forming method according to supplementary note 7, wherein the second interval is larger than the first interval. (6) (Supplementary Note 9) (a) A step of holding the substrate in a rotating cup having an upper opening and having an outlet through which gas flowing in from the upper opening is discharged; (C) dropping a coating liquid for forming a film on the substrate; and (c) transmitting a permeation flow through a second region around the first region above the substrate held by the rotating cup. Covering the open portion with a filter having a flow rate lower than the flow rate and a non-breathable lid overlying the filter; and (d) rotating the rotating cup at a first angular velocity to obtain a surface of the substrate. And (e) removing the lid from above the filter without removing the filter from the rotating cup, and rotating the rotating cup at a second angular velocity smaller than the first angular velocity. And drying the film. No film forming method. (7)

[0095]

According to the present invention, the in-plane variation of the film thickness when a film is formed on a substrate can be reduced. In particular, it is possible to reduce the variation in film thickness that occurs in the film drying step.

Therefore, it is possible to reduce the pattern size error caused by the in-plane variation of the film thickness.

[Brief description of the drawings]

FIG. 1 is a view showing the structure of a spin coating apparatus according to a first embodiment of the present invention. FIG. 1A is a cross-sectional view of a spin coating apparatus, and FIG. 1B is a perspective view showing a structure of a spin cup.

FIGS. 2 (A) to 2 (D) show the structure of a rotary hood in a spin coating apparatus according to a first embodiment of the present invention, and the steps for attaching and detaching the rotary hood to and from a rotary cup. FIG.

FIGS. 3A and 3B show a first embodiment of the present invention.
FIG. 5 is a view showing a film forming method according to an embodiment of the present invention.

FIGS. 4 (C) and 4 (D) show a first embodiment of the present invention.
FIG. 3B is a view showing a film forming method according to the example of FIG.
FIG.

FIG. 5 is a sectional view showing the structure of a spin coating device according to a second embodiment of the present invention.

FIGS. 6A and 6B show a second embodiment of the present invention.
FIG. 5 is a view showing a film forming method according to an embodiment of the present invention.

7 (C) and 7 (D) show a second embodiment of the present invention.
FIG. 6B is a view showing a film forming method according to the example of FIG.
It is a figure which shows the process of following.

FIG. 8 is a sectional view showing the structure of a modification of the spin coating device according to the second embodiment of the present invention.

FIG. 9A is a cross-sectional view showing the structure of the spin coating device proposed earlier. FIG. 9 (B) is the same as FIG. 9 (A)
FIG. 4 is a plan view showing a surface state of a resist film when a film is formed by the spin coating device shown in FIG.

[Explanation of symbols]

 Reference Signs List A rotation coating device C resist coating solution supply device R1 coating solution R2 resist film S square substrate T handle 1 rotation cup 3a stage 3b cup 4 open portion 5 discharge port 11 drive portion 13 spin motor 15 rotation shaft 21 rotation hood 22 filter frame Part 23 filter 23a low air permeability area 23b high air permeability area 23c main filter 24 sub filter 25 lid 27 gripping part 28 elevating mechanism 29 leg 31 exhaust hood 35 exhaust port

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2H025 AA18 AB08 DA20 EA05 4D075 AC64 AC92 DA06 DC22 4F042 AA07 EB06 EB16 EB24 5F046 JA07 JA08 JA13

Claims (7)

[Claims] 1. An apparatus according to claim 1, wherein the substrate is rotatable about a central axis, has an upper opening, and has an outlet through which gas flowing in from an upper opening is discharged. A rotating cup held inside so as to be vertical, a permeable filter capable of closing the opening, a non-permeable lid disposed on the filter, the filter, and the rotating cup A spin coating device having an interval adjusting mechanism capable of adjusting an interval between the substrate and an upper surface of the substrate held therein. 2. The apparatus according to claim 1, further comprising a lifting mechanism capable of lifting only the lid or lifting both the lid and the filter from a state where the lid and the filter cover the opening. Spin coating device. 3. The spin coating apparatus according to claim 1, further comprising a coating liquid supply device capable of dropping a coating liquid for forming a film on the substrate held by the rotary cup. 4. A substrate which is rotatable about a central axis, has an upper opening, and has an outlet through which gas flowing in from an upper opening is discharged. A rotating cup that is held inside so as to be vertical, a gas-permeable filter that can close the opening, and a gas-impermeable lid that is disposed on the filter. A spin coating apparatus wherein a permeation flow rate in a first region above a substrate held in a rotating cup is smaller than a permeation flow rate in a second region around the first region. 5. A step of: (a) holding a substrate in a rotating cup having an upper opening and having an outlet through which gas introduced from an upper opening is discharged; and (b) a film on a surface of the substrate. (C) a step of dropping a coating liquid for forming; (c) a step of covering the opening with a gas-permeable filter and a non-air-permeable lid overlaid on the filter; Forming a film covering the surface of the substrate by rotating the rotary cup at a first angular velocity with a distance between the filter and the surface of the substrate being a first distance; The lid is removed from the filter without being removed from the filter, and the interval between the filter and the surface of the substrate is changed to a second interval different from the first interval.
Rotating the film at a second angular velocity lower than the angular velocity to dry the film. 6. The film forming method according to claim 5, wherein the second interval is larger than the first interval. 7. A step of: (a) holding the substrate in a rotating cup having an upper opening and having an outlet through which gas introduced from the upper opening is discharged; and (b) a film on the surface of the substrate. (C) dropping a coating liquid for forming; and (c) making a permeation flow rate in a first area above the substrate held by the rotating cup higher than a permeation flow rate in a second area surrounding the first area. Covering the opening with a small filter and a non-breathable lid overlying the filter; and (d) rotating the rotating cup at a first angular velocity to cover the surface of the substrate. (E) removing the lid from above the filter without removing the filter from the rotating cup, and rotating the rotating cup at a second angular velocity smaller than the first angular velocity. Drying the film. Film forming method.