JPH11188304A - Coating apparatus, manufacture of reticle, and fabrication of semiconductor apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a fluid film with uniform thickness on the surface of a substrate by installing a holding stand for holding the substrate in a freely rotatable manner and using a filter part made of a porous medium and a sealing member practically closely attached to the filter part and made freely openable for constituting an enclosure formed on the holding stand. SOLUTION: In a resist application apparatus, a reticle substrate 13 is held on a holding stand 12 to be rotated at high speed by a motor 11 and an enclosure 14 is formed on the holding stand 12. A ventilation control constitution 250 is installed on the enclosure 14 and the ventilation control constitution 250 is constituted of a frame part 25 for holding a porous filter 25A and a cover 26 so installed as to be practically closely attached to the porous filter 25A. The cover 26 formed as to be freely detachable from the frame part 25. The enclosure 14 and the ventilation control constitution 250 are unitedly rotated with a substrate 13 when the holding stand 12 is rotated to rotate also the air enclosed in the enclosure 14, so that the film thickness of a resist film in corner parts of the substrate 13 is prevented from becoming thick.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention generally relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device including a step of applying a resist on a substrate. More specifically, the present invention relates to the manufacture of a reticle used in the manufacture of a semiconductor device, a resist coating apparatus therefor, and a method of manufacturing a semiconductor device using such a reticle.

[0002] The photolithography process is the most basic process of manufacturing a semiconductor device. The photolithography process uses an exposure mask generally called a reticle, and applies a resist layer applied on a substantially circular semiconductor wafer,
Exposure is performed with a pattern of a semiconductor device to be formed. On the other hand, the reticle used in such a photolithography process generally forms a resist mask by applying a resist layer on a square substrate, exposing and developing this into a desired pattern by electron beam exposure or the like, It is manufactured by patterning the substrate using the obtained resist mask.

Therefore, in the production of such a reticle,
It is necessary to form a resist layer on a square substrate.

[0004]

2. Description of the Related Art In general, since a semiconductor wafer has a substantially circular shape, when a resist layer is formed on such a semiconductor wafer, the semiconductor wafer is generally rotated at a high speed, the resist is dropped, and a centrifugal force is applied to the wafer surface. In general, a so-called spin coating method for diffusing by the method is used. Further, inexpensive resist coating apparatuses are commercially available for the purpose.

On the other hand, when a resist layer is formed on a square reticle using such a normal resist coating apparatus, the relative speed with respect to the surrounding air at the four corners of the reticle substrate rotating at a high speed increases. There is a problem that the liquid resist is preferentially dried and solidified. If the resist solidifies preferentially at the four corners of the substrate, the solidified resist prevents the liquid resist from diffusing outward due to centrifugal force. As a result, as shown in FIG. There is a problem that the thickness increases. Exposure of such a substrate does not provide a desired reticle pattern.

For this reason, conventionally, in applying a resist layer onto a reticle substrate, as shown in FIG. 6, a resist coating apparatus 10 in which a high-speed rotating enclosure is integrally formed around a high-speed rotating substrate is used. It is used. Referring to FIG. 6, a resist coating apparatus 10 holds a reticle substrate 13 on a holding table 12 rotated at a high speed by a motor 11, and further rotates on the holding table 12 integrally with the substrate 13. An enclosure 14 is formed. Further, on the enclosure 14, a lid 15 which rotates integrally is detachably mounted. Further, a fixed enclosure 16 is formed outside the enclosure 14, and the liquid resist discharged from the substrate 13 by centrifugal force is discharged to waste liquid processing.

FIGS. 7A to 7C are views for explaining a resist process on the reticle substrate 13 using the resist coating apparatus 10 of FIG. Referring to FIG. 7A, in this step, the motor 11 is stationary, the lid 15 is removed, and the resist 17 is dropped on the substrate 13. Next, in the step of FIG. 7B, the lid 15 is mounted on the enclosure 14, and the motor 11 is driven to move the substrate 13 to about 150 mm.
It is rotated at a rotation speed of 0 rpm for about 10 seconds. In this state, since the enclosure 14 and the lid 15 together with the holding table 12 form a closed space surrounding the substrate 13, the air in the closed space rotates together with the substrate 13, and as a result, FIG.
(4), there is no problem that the four corners of the substrate 13 are preferentially solidified. As a result of the process of FIG. 7B, a thin uniform film of the resist 17 is formed on the surface of the substrate 13.

Further, after the step of FIG.
In the step (C), the lid 15 is removed again and the resist film on the substrate 13 is dried by rotating the motor 11 at a low speed of about 50 rpm for about 60 seconds.

[0009]

As described above, using the resist coating apparatus shown in FIG.
By performing the resist step (C), the problem of the increase in the resist film thickness at the four corners of the substrate 13 shown in FIG. 5 is avoided. However, on the surface of the resist film on the substrate 13 thus formed, an irregular wind-like pattern having a pitch of about 2 to 3 mm was found as shown in FIG. The change in the thickness of the resist film due to the wind-like pattern reaches several tens of degrees to 100 degrees, causing irregular distortion in the exposed pattern.

Although the formation mechanism of such a wind-like pattern has not been sufficiently elucidated, it has been confirmed that the mechanism is generated at the time of shifting to the step (C) after the step (B) in FIG. This is probably due to the rapid drying of the resist film accompanying the removal of the lid 15 in the step (C) of FIG. Therefore, the inventor of the present invention has disclosed in Japanese Patent Application No. 9-0992.
In No. 52, as shown in FIG.
A porous filter 18 is provided on the top instead of the lid 15 so as to cover the substrate 13.
9 and control the drying speed of the resist film on the substrate 13 by evacuating through the hood 19. However, in FIG. 9, the previously described portions are denoted by the same reference numerals, and description thereof will be omitted.

However, in this configuration, it is troublesome to control the exhaust through the hood 19, and a favorable result cannot be obtained. This is because the air between the hood 19 and the porous filter 18 penetrates into the surface of the substrate 13 via the filter 18 in the configuration of FIG. Means that the air cannot be sufficiently controlled by the exhaust through the hood 19.

Accordingly, it is a general object of the present invention to provide a new and useful coating apparatus which solves the above-mentioned problems, a method of manufacturing a reticle using the coating apparatus, and a method of manufacturing a semiconductor device. A more specific object of the present invention is to avoid a problem of an increase in film thickness occurring at a corner of a substrate when a film is formed on a substrate having an arbitrary shape by spin coating of a volatile liquid material. An object of the present invention is to provide a coating apparatus capable of avoiding the formation of irregular irregularities on the surface, a method of manufacturing a reticle using the coating apparatus, and a method of manufacturing a semiconductor device.

[0013]

According to the present invention, as set forth in claim 1, there is provided a holding base for rotatably holding a substrate, and a holding base formed on the holding base, An enclosure that rotates integrally with the upper substrate, and a driving unit that rotates the holding table, in a coating apparatus that spin-coats a film on the substrate, the enclosure includes a filter unit made of a porous medium, 3. The coating device according to claim 2, wherein the sealing member is disposed substantially in close contact with the filter portion and comprises an openable sealing member. 4. A shutter provided on the porous medium by the coating device according to claim 1, further comprising a lid detachably provided on the porous medium. Characterized by a mechanism The filter device and the substrate on the holding table are separated from each other by the coating device according to claim 1 or as described in claim 4. The coating device according to any one of the preceding claims, or as described in claim 5, wherein the filter portion is formed detachably with respect to the enclosure. By the coating apparatus according to any one of the above, or as described in claim 6, a step of holding a reticle substrate on a rotatable holding table, and a step of dropping a resist on the reticle substrate on the holding table, On the holding table, so as to surround the reticle substrate on the holding table, by providing an enclosure having a porous filter, by further sealing the outer surface of the porous filter,
A step of sealing the reticle substrate, a step of rotating the holding table at a first speed while the reticle substrate is sealed to form a resist film on the reticle substrate, and an outer surface of the porous filter. Opening the hermetic seal and contacting the outside air with the resist film on the reticle substrate through the porous filter, and rotating the holding table at a second speed smaller than the first speed. And a step of drying the resist film, or the step of sealing the reticle substrate, wherein the step of sealing the reticle substrate is substantially performed on the porous filter. 7. A method for manufacturing a reticle according to claim 6, further comprising the step of providing a lid member in close contact with the porous filter, or as described in claim 8, The step of opening the seal is to provide a method of producing a reticle according to claim 7, characterized in that it comprises a step of removing the lid member from the porous filter,
Alternatively, as described in claim 9, the step of sealing the reticle substrate includes a step of providing a shutter member on the porous filter substantially in close contact with the shutter member in a state where the shutter member is closed. The method of manufacturing a reticle according to claim 6, wherein the step of opening the seal of the outer surface of the porous filter includes the step of opening the shutter member. A step of holding a reticle substrate on a rotatable holding table by the method of manufacturing a reticle according to claim 9 or as described in claim 11, wherein a resist is applied to the reticle substrate on the holding table. A step of dropping, on the holding base, an enclosure having a porous filter is provided so as to surround the reticle substrate on the holding base, and further, an outer surface of the porous filter is provided. Sealing, the step of sealing the reticle substrate, and, with the reticle substrate sealed, rotating the holding table at a first speed to form a resist film on the reticle substrate; Opening the sealing on the outer surface of the porous filter and contacting the resist film on the reticle substrate with outside air via the porous filter; and setting the holding table to a second speed lower than the first speed. Rotating the resist film at a predetermined speed, and drying the resist film. The method of manufacturing a semiconductor device, or as described in claim 12, wherein the step of sealing the reticle substrate comprises: 14. A method of manufacturing a semiconductor device according to claim 11, further comprising the step of providing a lid member substantially in close contact with the quality filter. The step of opening the sealing of the porous filter outer surface, by the method of manufacturing a semiconductor device according to claim 12, characterized in that it comprises a step of removing the lid member from the porous filter,
Alternatively, the step of sealing the reticle substrate includes a step of providing a shutter member substantially in close contact with the porous filter with the shutter member closed, on the porous filter. The method according to claim 11, wherein
16. A method for manufacturing a semiconductor device according to claim 15.
The method of manufacturing a semiconductor device according to claim 14, wherein the step of opening the seal of the outer surface of the porous filter includes the step of opening the shutter member. According to the present invention, when a fluid film such as a resist is spin-coated on a substrate having an arbitrary shape including a square shape, the substrate is rotated in a sealed environment. This solves the problem that the resist is rotated integrally with the substrate, so that the drying and solidification of the resist rapidly progresses at the periphery of the substrate, particularly at the corners of the substrate, and the thickness of the solidified resist film at the corners increases. Also, when performing the drying, because the resist film on the substrate gradually comes into contact with the outside air through the porous filter,
The generation of a pattern like a wind pattern on the surface of the solidified resist film can be suppressed. At that time, in the present invention, a sealing member such as a lid or a shutter is formed in close contact with the filter immediately outside the porous filter, and there is no substantial space between the sealing member and the shutter. There is no need to perform any complicated control such as exhausting the outside of the porous filter as in the related art, and good results can be obtained.

[0014]

1A and 1B are a sectional view and a plan view, respectively, showing a part of a resist coating apparatus according to a first embodiment of the present invention. Referring to FIGS. 1A and 1B, the configuration shown is a ventilation control configuration used in place of the sealing lid mounted on the enclosure 14 in the conventional resist coating apparatus 10 described above with reference to FIG. 250, the ventilation control configuration 250 includes a substantially circular frame portion 25 for holding a porous filter 25A made of stainless steel mesh or the like;
A lid 26 disposed on the frame portion 25 so as to be substantially in close contact with the porous filter 25A;
Is formed detachably with respect to the frame part 25 as shown in FIG. Further, a handle 26A is formed on the lid 26.

In the configuration shown in FIGS. 1A and 1B, as shown in FIG. 2, the frame 25 has a recess corresponding to the shape of the lid 26. As a result, the lid 26 is When mounted on the base 25, the ventilation through the porous filter 25A to the substrate 13 disposed in the enclosure 14 is substantially blocked. On the other hand, when the lid 26 is removed from the frame 25 as shown in FIG. 2, outside air is supplied to the substrate 13 through the porous filter 25A.

Next, a method of applying a resist on the reticle substrate 13 using the ventilation control structure 250 shown in FIGS. 1A and 1B will be described with reference to FIGS. 3A to 3C. .
However, the parts described above are given the same reference numerals,
Description is omitted. Referring to FIG. 3A, this step is substantially the same as the step of FIG.
A resist 17 is dropped on the reticle substrate 13 held inside the enclosure 14 while the holding table 12 and the substrate 13 are stationary.

Next, in the step of FIG.
The ventilation control structure 250 is mounted on the frame 25 with the lid 26 in close contact therewith, and the driving unit 11 is driven to rotate the holding table 12 and the reticle substrate 13 thereon at about 1500 rpm. Spin at speed for about 10 seconds. As a result, the resist 17 on the substrate 13 spreads over the substrate surface, and an uncured resist film having a uniform thickness is formed. By this rotation, the enclosure 14 and the ventilation control structure 250 thereon also rotate integrally with the substrate 13, so that the air in the enclosure 14 rotates with the substrate 13 as in the case of FIG. I do. Therefore, the problem of an increase in the thickness of the resist film at the corners of the substrate 13 as described with reference to FIG. 5 is avoided.

Further, in this embodiment, since the porous filter 25A is substantially sealed by the lid 26 mounted on the frame 25, outside air flows into the surface of the substrate 13 via the filter 25A. And the uncured resist film on the substrate 13 is not cured. Next, FIG.
In the step (C), the drive unit 11 is braked, and the holding table 12 is stopped. Further, from the frame portion 25 to the lid 26
Is removed to expose the porous filter 25A.
In this state, outside air flows from the porous filter 25A into the uncured resist film on the substrate 13, and drying and solidification of the resist film is started. At this time, in this embodiment, in order to promote the drying and solidification of the resist film, the driving unit 11 is driven, and the holding table 12 is moved at a low speed, for example, 50 rpm.
It is preferable to rotate for about 20 seconds.

Table 1 below shows that the porous filter 25A has an outer diameter of 220 mm and a differential pressure at 25 ° C. of 2 mm.
The results of measuring the film thickness distribution of a resist film obtained when a stainless steel wire mesh sintered porous plate having a permeation flow rate of 5.0 liter / cm ² / min at 54 mmH ₂ O is used are shown.

[0020]

[Table 1]

However, the above result indicates that the clearance (clearance) between the surface of the holding table 12 and the filter 25A is 10
mm, and the high-speed rotation in FIG.
rpm for 5 seconds, and the low-speed rotation shown in FIG.
This is for a case where the operation is performed at 0 rpm for 120 seconds. 152.0 mm × 15 for reticle substrate 13
A square substrate of 2.0 mm × 6.35 mm was used, and a novolak-type negative resist for electron beam was used as a resist. Also, during steps (B) and (C) of FIG. 3, a drain (not shown) for collecting excess resist through the outer fixed enclosure 16 is set to 20 mmH _{2 as} shown by the arrow.
Evacuated at O pressure.

Further, in Table 1, "Evaluation of in-plane film thickness distribution" means that the resist film thickness on the substrate 13 is an average film thickness [Ave] obtained by measuring 13 × 13 points at a pitch of 10 mm, The film thickness [Max], the minimum film thickness [Min], and the film thickness change range [Range] are shown. On the other hand, the [evaluation of wind ripple film unevenness] means that irregularities are formed at a pitch of 2 mm corresponding to the pitch of the wind ripple pattern. The average film thickness [Ave] and the maximum film thickness [Max] when the local film thickness change is measured for the formed portion.
], Minimum film thickness [Min], and film thickness change range [Range].

Table 1 shows the results for reticles # 1 to # 3 manufactured according to the present embodiment, and the results for reticles # 1 to # 3 manufactured by the conventional method shown in FIGS. 7A to 7C. Shown in comparison with. In Table 1, the unit of the numerical value is Å.
Table 1 shows that the present invention significantly reduces the width of change in the thickness of the resist film on the reticle in both the in-plane distribution evaluation and the wind ripple film unevenness evaluation as compared with the conventional case.

Table 2 shows the evaluation of the in-plane film thickness distribution when the clearance and the permeation flow rate of the porous filter 25A are changed in the present invention.

[0025]

[Table 2]

As can be seen from Table 2, when the clearance is 7 mm or more, the in-plane film thickness distribution is generally good. However, when the clearance is set to less than 7 mm, for example, 3 mm, the dispersion 3σ of the film thickness distribution is reduced. Very large. This is probably because, if the clearance is too small, the porous structure of the porous filter 25A is transferred to the resist film as it is. In order to avoid such transfer of the structure of the filter, the clearance is preferably set to about 7 mm or more, preferably about 10 mm.

The porous filter 25A in the present embodiment
Is not limited to the sintered stainless steel mesh as long as the porosity in the plane is uniform, other media,
For example, porous ceramics or the like can be used.
4A and 4B are a cross-sectional view and a plan view, respectively, illustrating a ventilation control configuration 251 according to a second embodiment of the present invention. However, the parts described above are denoted by the corresponding reference numerals, and description thereof will be omitted.

Referring to FIGS. 4A and 4B, in this embodiment, instead of the lid 26, the porous filter 2 is used.
A movable shutter mechanism 26C held in the frame portion 26B is formed in close contact with 5A. The movable shutter mechanism 26C
As in the case of the camera shutter, the area of the central opening 26D can be increased or decreased as indicated by the arrow. The frame 25B for holding the shutter mechanism 25C may be fixedly formed on the lower frame 25, or may be formed to be detachable.

In the above description, the substrate 13 is a rectangular reticle substrate. However, the present invention is not limited to such a specific substrate. Widely applicable. Further, the film formed on the substrate is not limited to a resist film, and the present invention is generally applicable to a film applied and dried in a fluid state.

Although the present invention has been described with reference to preferred embodiments, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims.

[0031]

According to the first to fifteenth aspects of the present invention, a fluid film such as a resist film is formed on a substrate having an arbitrary shape such as a square shape by spin coating, and further dried and dried.
When curing to form a solid film, the substrate is provided with a porous filter, disposed in a closed space that rotates integrally with the substrate, and the porous filter is sealed with a sealing member. By rotating the substrate at a high speed in the covered state, preferential drying of the fluid film in the peripheral portion of the substrate can be avoided, and a fluid film having a uniform thickness can be formed on the substrate surface. Further, after the high-speed rotation, the sealing member is removed, and the outside air is gradually brought into contact with the substrate through the porous filter, whereby a wind pattern formed on the film surface when the fluid film is dried and solidified is formed. Is suppressed, and a film having a uniform film thickness can be formed.

[Brief description of the drawings]

FIGS. 1A and 1B are views showing a part of a resist coating apparatus according to a first embodiment of the present invention.

FIG. 2 is another view showing the resist coating apparatus of FIG. 6;

FIGS. 3A to 3C are views showing a resist process using the resist coating apparatus of FIG. 1;

FIGS. 4A and 4B are views showing a part of a resist coating apparatus according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a problem that occurs when a resist film is formed on a reticle substrate using a conventional spin coating apparatus.

FIG. 6 is a diagram showing a configuration of a resist coating apparatus used to solve the problem of FIG.

FIGS. 7A to 7C are views for explaining a resist process using the resist coating apparatus of FIG. 6;

FIG. 8 is a diagram illustrating a problem that occurs in the process of FIG. 7;

FIG. 9 is a diagram showing a configuration of another conventional resist coating apparatus.

[Explanation of symbols]

 Reference Signs List 10 resist coating device 11 driving device 12 holding table 13 substrate 14 enclosure 15, 26 lid 16 outer enclosure 18, 25A porous filter 19 hood 25, 26B frame 26A handle 26C shutter mechanism 26D opening 250, 251 ventilation control structure

Claims (15)

[Claims] 1. A holding table for rotatably holding a substrate, an enclosure formed on the holding table and rotating integrally with the substrate on the holding table, and a driving unit for rotating the holding table. A coating device for spin-coating a film on the substrate, wherein the enclosure comprises a filter portion made of a porous medium, and a sealing member disposed substantially in close contact with the filter portion and capable of being opened freely. A coating device characterized by the above-mentioned. 2. The coating apparatus according to claim 1, wherein said sealing member comprises a lid detachably provided on said porous medium. 3. The coating apparatus according to claim 1, wherein the sealing member comprises a shutter mechanism provided on the porous medium. 4. The apparatus according to claim 1, wherein the filter unit and the substrate on the holding table are separated from each other.
The coating device according to claim 1. 5. The filter according to claim 1, wherein the filter is detachably attached to the enclosure.
The coating device according to any one of the preceding claims. 6. A step of holding a reticle substrate on a rotatable holder, a step of dropping a resist on the reticle substrate on the holder, and a step of placing a reticle substrate on the holder on the holder. A step of sealing the reticle substrate by providing an enclosure having a porous filter so as to surround the outer surface of the porous filter, and sealing the reticle substrate. 1
Forming a resist film on the reticle substrate by rotating at a speed of; and opening the sealing of the outer surface of the porous filter to allow the resist film on the reticle substrate to be exposed to outside air through the porous filter. And a step of rotating the holding table at a second speed lower than the first speed to dry the resist film. 7. The reticle manufacturing method according to claim 6, wherein the step of sealing the reticle substrate includes the step of providing a lid member on the porous filter substantially in close contact. 8. The reticle manufacturing method according to claim 7, wherein the step of opening the seal on the outer surface of the porous filter includes a step of removing the lid member from the porous filter. 9. The method according to claim 1, wherein the step of sealing the reticle substrate includes the step of providing a shutter member on the porous filter substantially in close contact with the shutter member with the shutter member closed. Item 7. A method for producing a reticle according to Item 6. 10. The reticle manufacturing method according to claim 9, wherein the step of opening the seal on the outer surface of the porous filter includes the step of opening the shutter member. 11. A step of holding a reticle substrate on a rotatable holder, a step of dropping a resist on the reticle substrate on the holder, and a step of placing a reticle substrate on the holder on the holder. A step of sealing the reticle substrate by providing an enclosure having a porous filter so as to surround the outer surface of the porous filter, and sealing the reticle substrate. 1
Forming a resist film on the reticle substrate by rotating at a speed of; and opening the sealing of the outer surface of the porous filter to allow the resist film on the reticle substrate to be exposed to outside air through the porous filter. And a step of rotating the holding table at a second speed lower than the first speed to dry the resist film. 12. The step of sealing the reticle substrate,
12. The method of manufacturing a semiconductor device according to claim 11, further comprising a step of providing a lid member substantially in close contact with the porous filter. 13. The method according to claim 12, wherein the step of opening the seal on the outer surface of the porous filter includes the step of removing the lid member from the porous filter. 14. The step of sealing the reticle substrate,
The shutter is substantially in close contact with the porous filter.
The method for manufacturing a semiconductor device according to claim 11, further comprising a step of providing a member with the shutter member closed. 15. The method according to claim 14, wherein the step of opening the seal on the outer surface of the porous filter includes the step of opening the shutter member.