JP2006019472A - Apparatus and method for reduced pressure drying - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reduced pressure drying apparatus which does not make to generate a minute defect on the front surface of a coating film by eliminating the ununiformity of the film thickness resulting from a remaining solvent in reduced pressure drying used when a pattern is formed by a photolithography method, and to provide a reduced pressure drying method. <P>SOLUTION: In the reduced pressure drying apparatus used when the pattern is formed, a top plate provided above a surface plate 3 which places the substrate 1 in the reduced pressure drying apparatus is a top plate 14 having an opening. The top plate is two top plates of the top plate 14 having the opening and a top plate 44 having no opening above the top plate 14. An exhaust system has two exhaust systems of a first exhaust system 20 above the top plate having the opening and a second exhaust system 30 above the top plate having no opening. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for forming a pattern on a substrate, and in particular, in a reduced-pressure drying apparatus used when forming a pattern by a photolithography method, film thickness non-uniformity due to reduced-pressure drying, and minute defects The present invention relates to a reduced-pressure drying apparatus and a reduced-pressure drying method that do not cause generation.

  FIG. 8 is a plan view schematically showing an example of a color filter used in a liquid crystal display device or the like. FIG. 9 is a cross-sectional view of the color filter shown in FIG. 8 taken along line X-X ′. As shown in FIGS. 8 and 9, the color filter used in the liquid crystal display device or the like is obtained by forming a black matrix (52) and a colored pixel (51) on a substrate (50).

The black matrix (52) is a matrix having a light shielding property, and the colored pixels (51) have, for example, functions of red, green, and blue color reproduction filters.
The black matrix (52) makes the position and size of the colored pixels (51) of the color filter uniform, and when used in a display device, it blocks unwanted light and makes the image of the display device uneven. It has a function of making a uniform image with no contrast and improved contrast.

The black matrix (52) and the colored pixels (51) are often formed by a photolithography method. The black matrix (52) is formed of chromium (Cr) and chromium oxide (CrO _x ) on a glass substrate (50). A metal or metal compound such as a thin film is formed, an etching resist pattern is formed on the formed thin film using, for example, a positive photoresist, and then the formed metal thin film is formed. The exposed portion was etched and the etching resist pattern was stripped to form a black matrix. Alternatively, the black matrix (52) is formed by photolithography using a photoresist containing a black pigment.

  Further, the colored pixel (51) is formed as a colored pixel on a substrate on which a black matrix is formed, for example, by using a negative photoresist containing a pigment by a photolithography method.

  When these black matrix (52) and colored pixels (51) are formed as a pattern by a photolithography method, for example, the substrate is first subjected to a cleaning treatment as necessary, and then a photoresist is applied by a coating apparatus. Then, a pre-bake process by the heat treatment unit, a pattern exposure by the exposure apparatus, a development process by the development process unit, and a post-bake process by the heat process unit are sequentially performed to form a predetermined pattern on the substrate.

Immediately after application of the photoresist, the coating film of the photoresist is fluid because it is not dried. When the substrate is transported to the next process, the film thickness of the coating film is likely to change during transportation. May cause unevenness.
In addition, floating particles or the like are likely to adhere during conveyance of the substrate to the next process, and defective products may be generated.

In the pre-bake treatment, when the photoresist coating is not sufficiently dried from the insufficient drying state, the contact mark between the fixing pin for fixing the substrate and the lifting pin for lifting the substrate and the substrate May appear on the substrate after development processing. This phenomenon is caused by the fact that the thermal history of the substrate is different between the portion that is in contact with the lifting pins and the like and the portion that is not in contact.

  In order to prevent such a change in the film thickness of the coating film, to prevent adhesion of particles, etc., and to prevent contact marks such as lifting pins, a vacuum drying treatment is performed on the coating film immediately after coating. . The vacuum drying process is a preliminary drying process in which the solvent in the coating film is half evaporated and boiled.

FIG. 1 is a plan view illustrating an outline of an example of a reduced pressure drying apparatus used in a reduced pressure drying process. 2 is a cross-sectional view taken along line XX ′ of FIG.
As shown in FIGS. 1 and 2, this vacuum drying apparatus shown as an example includes a lower housing (2A), an upper housing (2B), a surface plate (3), and a top plate (4). By attaching the upper housing (2B) to the lower housing (2A), the inside becomes a sealed chamber. A plurality of exhaust ports (5) are provided on the upper surface of the upper housing (2B).

An exhaust hose (6) is connected to the exhaust port (5), and the exhaust hose (6) is connected to an exhaust device (not shown). The air in the sealed chamber is exhausted by the operation of the exhaust device, and the pressure in the chamber is reduced.
When the substrate (1) is placed on and removed from the surface plate (3), the upper housing (2B) moves up and down as indicated by the white arrow. The top plate (4) and the exhaust hose (6) are moved up and down integrally with the upper housing (2B).

The top plate (4) is a rectangular flat plate having substantially the same size as the substrate (1). The top plate (4) is provided to rectify the exhaust. When the top plate (4) is not provided, drying immediately below the exhaust port (5) is accelerated, and the film thickness of the coating film on the substrate (1) changes locally.
FIG. 2 shows a state in which the substrate (1) just after the photoresist is applied is placed on the surface plate (3) and exhausted. The arrow represents the streamline of the exhaust gas. By this exhaust gas, the solvent in the coating film is evaporated and boiled halfway, and preliminary drying is performed.

However, in the reduced-pressure drying process using such a reduced-pressure drying apparatus, the exhaust gas flow velocity at the central portion of the substrate is lower than that at the peripheral portion, so that the remaining solvent tends to increase. This tendency becomes more prominent as the size of the substrate becomes larger, for example, as the size becomes larger, for example, 1500 mm × 1800 mm, and the remaining solvent becomes a problem that has become apparent. That is, the film thickness of the portion where the remaining solvent is large becomes low, and the film thickness non-uniformity caused by the residual solvent in the substrate surface becomes a problem.
On the other hand, since the exhaust velocity at the peripheral edge of the substrate is high, pinholes called minute defects are generated on the surface of the coating film due to rapid evaporation and boiling of the solvent.
JP 2001-269607 A Japanese Patent Laid-Open No. 10-233599

The present invention has been made to solve the above problems, and in a reduced-pressure drying apparatus used when a pattern is formed on a substrate by a photolithography method, film thickness non-uniformity caused by residual solvent in the substrate surface It is an object of the present invention to provide a reduced-pressure drying apparatus that eliminates the above-described problem and does not generate micro defects on the surface of the coating film.
In addition, in the reduced-pressure drying process that is performed when a pattern is formed on the substrate by photolithography, the non-uniformity of the film thickness due to the residual solvent in the substrate surface is eliminated, and the surface of the coating film has minute defects. It is an object of the present invention to provide a reduced-pressure drying method that does not cause generation.

  The present invention relates to a vacuum drying apparatus used for forming a pattern on a substrate by a photolithography method, wherein a top plate provided above a surface plate on which a substrate is placed in the vacuum drying apparatus has an opening. A vacuum drying apparatus characterized by being a plate.

  In the vacuum drying apparatus used when forming a pattern on a substrate by a photolithography method, the top plate provided above the surface plate on which the substrate inside the vacuum drying apparatus is mounted has an opening. And a top plate having no opening above the top plate, the exhaust system having a first exhaust system above the top plate having an opening, and a top plate above the top plate having no opening. A reduced-pressure drying apparatus characterized by being a two-exhaust two-exhaust system.

  The present invention is the vacuum drying apparatus according to the above invention, wherein the shape of the opening is circular or polygonal.

  Moreover, the present invention is the vacuum drying apparatus according to the above invention, wherein the circular diameter or one side of the polygon is 1 mm to 50 mm.

The present invention is the vacuum drying apparatus according to the above invention, wherein the number of the openings is 1 to 20 × 10 ³ / m ² .

  The present invention is the vacuum drying apparatus according to the above invention, wherein the opening ratio of the opening is 0.1% to 50%.

  The present invention is the vacuum drying apparatus according to the above-described invention, wherein the pattern is a pattern of a color filter for a liquid crystal display device.

  Moreover, this invention is a reduced pressure drying method using the reduced pressure drying apparatus of any one of Claims 1-7.

  In the present invention, since the top plate provided above the surface plate on which the substrate in the vacuum drying apparatus is placed is a top plate having an opening, the film thickness is uneven due to the residual solvent in the substrate surface. It becomes a reduced-pressure drying apparatus which eliminates the property and does not generate micro defects on the surface of the coating film.

  In the present invention, the top plate provided above the surface plate on which the substrate in the vacuum drying apparatus is placed has a top plate having an opening and a top plate having no opening above the top plate. Because the exhaust system is a two exhaust system of the first exhaust system above the top plate having an opening and the second exhaust system above the top plate having no opening, the exhaust system is caused by residual solvent in the substrate surface. The reduced-pressure drying apparatus can eliminate the non-uniformity of the film thickness and can increase the processing capacity per hour without causing micro defects on the surface of the coating film.

  In addition, the reduced-pressure drying apparatus according to the present invention is a reduced-pressure drying apparatus in which the effect is remarkably exhibited in forming a pattern having a thick film thickness, such as a black matrix or a colored pixel of a color filter for a liquid crystal display device.

In addition, since the reduced-pressure drying method according to the present invention uses the reduced-pressure drying apparatus according to the above-described invention, when the pattern is formed on the substrate by the photolithography method, the non-uniformity of the film thickness due to the residual solvent in the substrate surface is eliminated. In addition, the reduced-pressure drying method does not cause micro defects on the surface of the coating film.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 3 is a plan view schematically showing an embodiment of the reduced-pressure drying apparatus according to the present invention. 4 is a cross-sectional view taken along line XX ′ of FIG.
As shown in FIG. 3 and FIG. 4, this vacuum drying apparatus shown as an example is composed of a lower casing (2 A), an upper casing (2 B), a surface plate (3), and a top plate (14). Yes. By attaching the upper housing (2B) to the lower housing (2A), the inside becomes a sealed chamber. A plurality of exhaust ports (5) are provided on the upper surface of the upper housing (2B).

An exhaust hose (6) is connected to the exhaust port (5), and the exhaust hose (6) is connected to an exhaust device (not shown). The air in the sealed chamber is exhausted by the operation of the exhaust device, and the pressure in the chamber is reduced.
When the substrate (1) is placed on and removed from the surface plate (3), the lower housing (2A) moves up and down as indicated by the white arrow. The top plate (14) and the exhaust hose (6) are fixed integrally with the upper housing (2B).

The top plate (14) in the present invention is a top plate having an opening (7). Fig.5 (a) is a top view of the top plate (14) which has the said opening part. As shown to Fig.5 (a), the opening part (7) is provided with two or more by the center part of the top plate.
By providing a top plate (14) having an opening above the surface plate (3) on which the substrate is placed, the exhaust is arranged at the peripheral edge of the substrate (1), as shown by the arrows in FIG. In addition to the above, the air is exhausted from the central portion of the substrate (1), and the exhaust flow velocity in the central portion is increased. Thereby, the residual solvent in the central part of the coating film formed on the substrate is reduced and becomes substantially uniform in the substrate surface.
Therefore, the film thickness non-uniformity due to the residual solvent in the substrate surface is improved.

Further, since the exhaust is performed from the central portion of the substrate (1), the exhaust flow velocity at the peripheral portion of the substrate is lowered. Therefore, rapid evaporation and boiling of the solvent on the surface of the coating film are eliminated, and generation of micro defects is suppressed.
In FIG. 5 (a), the dotted line represents the position of the exhaust port (5) above the top plate.

  In addition, the degree of film thickness non-uniformity caused by residual solvent in the substrate surface, and the degree of occurrence of minute defects caused by evaporation and boiling of the solvent at the peripheral edge are, for example, those of the photoresist used for pattern formation. It differs depending on the composition or the thickness of the coating film. Therefore, it is preferable to use a top plate provided with an opening portion suitable for the composition of the photoresist or the thickness of the coating film.

  For example, in a reduced-pressure drying apparatus provided with a top plate (14) having an opening shown in FIG. 5A, when a photoresist having a certain composition is used, the film thickness caused by residual solvent at the peripheral edge of the substrate. When a micro defect is observed in the central portion, the top plate (14) having the opening is not exhausted from the central portion of the photoresist having the certain composition. The flow rate is excessive, and correction for reducing the difference between the exhaust velocity at the central portion and the exhaust velocity at the peripheral portion is required.

In such a case, it is preferable to use a top plate (24) having an opening shown in FIG. As shown in FIG. 5 (b), in the top plate (24) having an opening, the opening (7) is located not only in the central portion of the top plate but also in the direction of the peripheral portion, directly below the outlet (5). Is provided to avoid.
As a result, the difference between the exhaust velocity at the central portion and the exhaust velocity at the peripheral portion is reduced, and a top plate having an opening portion suitable for the photoresist having the certain composition is obtained.

  Moreover, although the top plate (34) which has an opening part shown in FIG.5 (c) is a top view of another example of the top plate which has an opening part, the top plate which has an opening part shown in FIG.5 (b) It is a top plate which brings about the same effect as (24). The top plate (34) having an opening is an example of a top plate aiming at further suppressing the generation of minute defects at the peripheral edge of the substrate as compared with the top plate (24) having an opening.

  If the variation in the film thickness in the substrate surface when the conventional vacuum drying apparatus is used is 100, the variation in the film thickness in the substrate surface is about 80 by using the vacuum drying apparatus according to the present invention. Improved results have been obtained.

In the present invention, the shape of the opening (7) is not particularly limited, but the shape of the opening is preferably circular or polygonal. Moreover, it is preferable that one side of a circular diameter or a polygon is 1 mm-50 mm.
The number of openings is preferably 1 to 20 × 10 ³ / m ² , and the opening ratio of the openings is preferably 0.1% to 50%.
In addition, the reduced-pressure drying apparatus according to the present invention has the effect of the reduced-pressure drying apparatus according to the present invention remarkably in forming a pattern having a thick film thickness, such as a black matrix or a colored pixel of a color filter for a liquid crystal display device.

  FIG. 6 is a cross-sectional view showing an outline of an example of the reduced-pressure drying apparatus according to the second aspect of the present invention. The reduced-pressure drying apparatus shown in FIG. 6 is a reduced-pressure drying apparatus designed to shorten the time required for the reduced-pressure drying process in the reduced-pressure drying apparatus according to the first aspect of the present invention. As described above, the reduced-pressure drying apparatus of the invention according to claim 1 eliminates the non-uniformity of the film thickness due to the residual solvent in the substrate surface, and also generates micro defects on the surface of the coating film. There is no vacuum drying equipment.

However, in order to increase the processing capacity per hour, for example, if the exhaust capacity is increased to shorten the exhaust time, minute defects are likely to occur. That is, it became clear that the effect by this invention is lost.
As a result of reexamining the reduced-pressure drying process, the present inventor has found a reduced-pressure drying method that does not generate micro defects even if the exhaust capacity is increased and the exhaust time is shortened. It came.

The vacuum drying process will be described in more detail.
1) The first step of lowering the pressure in the chamber until reaching the boiling point of the solvent in the coating film at that temperature. 2) A second step in which the pressure in the chamber is lowered to a lower value and the boiling of the solvent is accelerated.
3) The third step of returning the pressure in the chamber to atmospheric pressure by purging with nitrogen after almost all the solvent in the coating film has boiled.

In the first step, the solvent in the coating film is evaporated, but the solvent is not boiled and is a gentle vacuum drying step. The evaporation of the solvent in this step hardly causes micro defects in the coating film.
In the second step, the solvent in the coating film is boiled. If the solvent is boiled rapidly in this step, it is assumed that minute defects are generated in the coating film.

The present invention is intended to shorten the exhaust time by increasing the exhaust capacity in the first step, where there are almost no occurrences of minute defects.
That is, in the first step, the exhaust capacity is increased in the state where the top plate (44) having no opening is functioned without functioning the top plate (14) having the opening shown in FIG. The exhaust time is shortened by exhausting from the peripheral edge of 1).
In the next second step, in order to avoid the occurrence of minute defects, as shown in FIG. 7, the top plate (14) having an opening portion is not functioned without functioning the top plate (44) having no opening portion. To make the solvent in the coating film boil.

  Thereby, similarly to the reduced-pressure drying apparatus of the invention according to claim 1, the non-uniformity of the film thickness due to the residual solvent in the substrate surface is eliminated, and the fine defect is not generated on the surface of the coating film. In addition, the reduced-pressure drying apparatus has an improved processing capacity per hour.

  As shown in FIG. 6, the reduced-pressure drying apparatus of the invention according to claim 2 includes a lower casing (12A), an upper casing (12B), a surface plate (3), a top plate (14) having an opening, and an opening. It comprises a top plate (44) having no part, a first exhaust system (20), and a second exhaust system (30). By attaching the upper housing (12B) to the lower housing (12A), the inside becomes a sealed chamber.

The top plate provided above the surface plate (3) on which the substrate (1) is placed is a two top plates, a top plate (14) having an opening and a top plate (44) having no opening, Above the surface plate (3), the top plate (14) having an opening toward the upper surface of the upper casing (12B) and the top plate (44) having no opening are provided in this order.
A plurality of first exhaust ports (15) are provided through a part of the top plate (44) having no opening. A plurality of second exhaust ports (25) are provided on the upper surface of the upper housing (12B).

The exhaust system has two exhaust systems, a first exhaust system (20) above the top plate (14) having an opening and a second exhaust system (30) above the top plate (44) having no opening.
The first exhaust system (20) includes a first exhaust hose (16) and a first on-off valve (18), and one end of the first exhaust hose (16) is connected to the first exhaust port (15). The other end is connected to an exhaust device (not shown).
The second exhaust system (30) includes a second exhaust hose (26) and a second on-off valve (28), and one end of the second exhaust hose (26) is connected to the second exhaust port (25). The other end is connected to an exhaust device (not shown).

The first exhaust system (20) and the second exhaust system (30) are operated separately. This is performed by opening the first on-off valve (18) and closing the second on-off valve (28), or closing the first on-off valve (18) and opening the second on-off valve (28).
By the operation of the exhaust device and the first exhaust system (20) or the operation of the exhaust device and the second exhaust system (30), the air in the sealed chamber is exhausted and the pressure in the chamber is reduced. .

  Further, when the substrate (1) is placed on and taken out from the surface plate (3), the lower housing (12A) moves up and down as indicated by the white arrow. The top plate (14) having the opening, the top plate (44) not having the opening, the first exhaust system (20), and the second exhaust system (30) are fixed integrally with the upper housing (12B). ing.

FIG. 6 is a sectional view showing a state where the second on-off valve (28) is opened and the second exhaust system (30) is operated. At this time, the first on-off valve (18) is closed, and the first exhaust system (20) is not operating.
Therefore, as indicated by arrows of exhaust streamlines, the top plate (44) between the substrate (1) and the top plate (14) having the opening, and the top plate (14) having the opening and the top plate (44) having no opening. The air in between is exhausted from the peripheral edge of the substrate through the second exhaust system (30).

On the other hand, FIG. 7 is a sectional view showing a state in which the first on-off valve (18) is opened and the first exhaust system (20) is operated. At this time, the second on-off valve (28) is closed, and the second exhaust system (30) is not operating.
Accordingly, as indicated by arrows of exhaust streamlines, air between the substrate (1) and the top plate (14) having the opening is exhausted from the peripheral and central portions of the substrate through the first exhaust system (20). The Further, the air between the top plate (44) having no opening and the upper housing (12B) is exhausted from the peripheral portion of the substrate through the first exhaust system (20).
The exhaust state shown in FIG. 7 is substantially the same as the exhaust state in the vacuum drying apparatus according to the first aspect of the invention.

That is, in the vacuum drying apparatus of the invention according to claim 2, the first step of the vacuum drying step has an opening until the exhaust state shown in FIG. 6, that is, immediately before the solvent in the coating film starts boiling. The top plate (14) is not functioned, and the top plate (44) having no opening is functioned to increase the exhaust capacity and reduce the exhaust time without causing micro defects in the coating film.
Next, the second step of the reduced-pressure drying step is an exhaust state shown in FIG. 7, that is, after the solvent in the coating starts to boil, the top plate (14) having an opening is made to function, Drying under reduced pressure is performed without generating minute defects and without causing variations in film thickness due to residual solvent.

Therefore, by using the reduced-pressure drying apparatus of the invention according to claim 2, the non-uniformity of the film thickness due to the residual solvent in the substrate surface is eliminated, and micro defects are generated on the surface of the coating film. And the processing capacity per hour can be increased.
Note that the film thickness variation is improved to about 80, assuming that the film thickness variation in the substrate surface when a conventional vacuum drying apparatus is used is 100.

It is a top view which shows the outline of an example of the reduced pressure drying apparatus used for a reduced pressure drying process. It is sectional drawing in the X-X 'line | wire of FIG. It is a top view which shows the outline of one Example of the vacuum drying apparatus by this invention. FIG. 4 is a cross-sectional view taken along line X-X ′ in FIG. 3. (A) is a top view of the top plate which has an opening part. (B) is a top view of the other first example of the top plate which has an opening part. (C) is a top view of the other 2nd example of the top plate which has an opening part. It is sectional drawing of the reduced pressure drying apparatus concerning Claim 2. It is sectional drawing of the reduced pressure drying apparatus concerning Claim 2. It is the top view which showed typically an example of the color filter used for a liquid crystal display device etc. It is sectional drawing in the X-X 'line | wire of the color filter shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 50 ... Board | substrate 2A, 12A ... Lower housing | casing 2B, 12B ... Upper housing | casing 3 ... Surface plate 4 ... Top plate 5 ... Exhaust port 6 ... Exhaust hose 7 ... Openings 14, 24, 34 ... Top plate 15 having openings in the present invention ... First exhaust port 16 ... First exhaust hose 18 ... First on-off valve 20 ... 1st exhaust system 25 ... 2nd exhaust port 26 ... 2nd exhaust hose 28 ... 2nd on-off valve 30 ... 2nd exhaust system 44 ... Top plate which does not have the opening part in this invention 51 ... Colored pixels 52 ... Black matrix

Claims (8)

  In a vacuum drying apparatus used when a pattern is formed on a substrate by a photolithography method, the top plate provided above the surface plate on which the substrate in the vacuum drying device is placed is a top plate having an opening. A vacuum drying apparatus characterized by the above.   In a vacuum drying apparatus used when a pattern is formed on a substrate by a photolithography method, a top plate provided above a surface plate on which a substrate in the vacuum drying device is placed is a top plate having an opening, Two top plates of a top plate having no upper opening, and two exhausts of a first exhaust system above the top plate having an opening and a second exhaust system above the top plate having no opening A vacuum drying apparatus characterized by being a system.   The reduced-pressure drying apparatus according to claim 1 or 2, wherein the shape of the opening is circular or polygonal.   The reduced-pressure drying apparatus according to claim 3, wherein one side of the circular diameter or polygon is 1 mm to 50 mm. 5. The reduced-pressure drying apparatus according to claim 1, wherein the number of the openings is 1 to 20 × 10 ³ pieces / m ² .   The vacuum drying apparatus according to claim 1, 2, 3, 4, or 5, wherein an opening ratio of the opening is 0.1% to 50%.   The reduced-pressure drying apparatus according to claim 1, wherein the pattern is a color filter pattern for a liquid crystal display device.   A reduced-pressure drying method using the reduced-pressure drying apparatus according to any one of claims 1 to 7.

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