JPH0510985B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is capable of forming a uniform thin film on the surface of a substrate by depositing a liquid containing a thin film forming component in an organic solvent on the surface of the substrate. The present invention relates to a thin film forming apparatus, and can be particularly used for forming thin films as exemplified below.

For example, in a fluorescent display tube that is observed through the board, a transparent conductive film is provided on the inner surface of the front plate to shield external electric fields, and in a so-called front-emitting type fluorescent display tube that is observed through the substrate, it is used as an anode conductor and a wiring conductor. It is useful for forming a transparent conductive film provided on an anode substrate.

Furthermore, transparent conductive films used for electrodes of liquid crystal display devices, transparent oxide films formed on the surface of glass plates as a barrier to prevent the elution of alkaline components, and
To form a thin film that is formed on the surface of a glass plate to strengthen it, and a thin film that is applied to the surface of a glass plate to provide various features such as anti-reflection and improved heat reflection. It can also be used for

[Prior Art] A three-roll roll coater shown in FIG. 8 is known as an apparatus for depositing a thin film on the surface of a substrate such as glass.

The roll coater 1 includes a back-up roller 3 that supports the substrate 2 from below, and a coating roller 5 that is pressed against the upper surface of the substrate 2 and transfers the thin film forming liquid 4 onto the substrate 2. , is poured onto a doctor roller 6, is uniformly spread by the doctor roller 6, and is supplied to the coating roller 5.

Additionally, a depping method is known as another method for forming a thin film on the surface of a substrate. The depping method involves forming a thin film on both sides of the substrate by setting up a tank large enough to accommodate the entire substrate, filling it with a thin film forming solution, and then immersing the substrate in it, then pulling it up and drying it. It is.

[Problems to be Solved by the Invention] A roll coater can be used to coat a substrate with a stable thin film forming liquid that does not easily deteriorate, but it cannot be used when the thin film forming liquid is unstable. Can not do it. For example, consider the case of a thin film forming liquid in which an organometallic compound (alkoxy compound) containing indium, tin, titanium, etc. is dissolved in an organic solvent that has a low boiling point and is easily volatile.

Before the liquid is transferred as a thin film onto the substrate 2, pressure is applied twice between the doctor roller 6 and the coating roller 5 and between the coating roller 5 and the substrate 2. Furthermore, since the solvent component of the liquid continues to volatilize from the stage when it is supplied to the doctor roller 6, the liquid continues to evaporate from the coating roller 6.
is not transferred uniformly. Therefore, of the liquid adhering to the coating roller 5, the part where the solvent component has not volatilized is transferred to the substrate 2, but the part where the solvent component has evaporated remains attached to the coating roller 5 and is transferred to the substrate 2. is not transcribed. Therefore, the thin film formed on the substrate 2 becomes non-uniform.

Further, according to the roll coater, it is necessary to sandwich the substrate 2 between the backup roller 3 and the coating roller 5, so when using substrates of different thicknesses, it is necessary to adjust the spacing between the rollers.

Therefore, when using an unstable thin film forming liquid as mentioned above, the above-mentioned dipping method is applied, but this method requires a sufficient amount of liquid to immerse the entire substrate. However, there was a problem that it was not economical because the amount of liquid deteriorated over time increased.

Also, when the substrate is pulled out of the liquid after immersion,
The problem is that the thickness of the thin film formed is not constant because volatilization starts from the top of the substrate that was pulled up first, and the liquid that flows down the surface of the substrate after being lifted tends to accumulate in the lower part of the substrate. The point was hot.

Furthermore, since the entire substrate is immersed, there is a problem in that in order to form a thin film on only one side of the substrate, the other side must be shielded, which is not easy as in the case of the roll coater method.

[Objective of the Invention] The present invention has been made to solve the above-mentioned problems, and can be applied to unstable thin film forming liquids, and can easily form a uniform and high quality thin film on only one side of a substrate. It can be formed into
It is an object of the present invention to provide an economical thin film forming apparatus that uses a small amount of thin film forming liquid.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the thin film forming apparatus of the present invention includes a substrate cleaning section including a substrate transfer means and a substrate cleaning device, and a cleaning section for cleaning the cleaned substrates. A dehydrating/drying section equipped with a dehydrating/drying means for removing the cleaning liquid, a cooling transfer section having a transfer guide means that contacts only both sides of the substrate, a saucer for storing the thin film forming liquid, and a tray for storing the thin film forming liquid in the tray. and a coating roller disposed so that a portion thereof is immersed, and when the substrate comes into contact with the coating roller, the transfer guide means temporarily stops and the rotating coating roller transfers the thin film forming liquid onto the substrate. A coating section configured to collect on the back surface, a pooled liquid cut section having a vertically movable cutter disposed below the discharge side transfer guide means, and a transfer heating section for drying the thin film of the substrate to be transferred. are arranged continuously inside the case while being isolated from the outside world.

[Operation] The substrate is first sent to the substrate cleaning section, and while being transferred by the transfer means, the surface is cleaned by the substrate washer.

Next, the cleaned substrate is sent to a dehydrating and drying section, and the cleaning liquid adhering to the surface is removed by the heating action of the dehydrating and drying means.

Next, the substrate is continuously fed into a cooling transfer section. The substrate, which has been heated in the previous step and whose temperature has increased, is cooled while being transferred by the transfer guide means, and is adjusted to a temperature suitable for applying the thin film forming liquid. Further, since the transfer guide means is configured to guide and transfer the substrate by contacting only both sides of the substrate that has been cleaned and dried, the surface of the substrate is not contaminated.

Next, the substrate, which has been adjusted to an appropriate temperature, is sent to the coating section. Since the coating roller of the coating section rotates with a portion immersed in the thin film forming liquid contained in the saucer, the thin film forming liquid always adheres to the surface of the coating roller.

When the substrate is fed onto the coating roller, the lower surface of the tip of the substrate comes into contact with the top of the outer peripheral surface of the coating roller. Then, as the transfer guide means temporarily stops and the coating roller rotates, a pool of the thin film forming liquid is generated due to surface tension in the gap between the substrate and the coating roller in front of the contact portion.

The substrate is slid over a pool of the thin film forming liquid and transferred over the coating roller, so that the thin film forming liquid is uniformly applied to the lower surface of the substrate.

Next, the substrate is fed into a pooled liquid cut section. The substrate is transported by a discharge side transfer guide means that contacts only both sides of the substrate, and excess thin film forming liquid accumulated on the lower surface of the rear end of the substrate is removed by operation of the cutter.

Next, the substrate is fed into a transfer heating section. In this step, the thin film forming liquid is heated and dried to form a uniform thin film on the lower surface of the substrate. The substrate on which the thin film has been formed is then transferred to the outside of the apparatus.

[Example] Examples of the present invention will be described below.

FIG. 1 is a front view showing the overall configuration of the thin film forming apparatus, and 7 in the figure is a substrate cleaning section. As shown in FIG. 2, the substrate cleaning section 7 is provided with a substrate cleaning device 9 and a plurality of pairs of feed rollers 11 serving as means for transporting the substrate 10 inside a case 8. The inside of the building is isolated from the outside world, and the internal temperature, humidity, etc. are kept constant. The feed rollers 11 are composed of a pair of upper and lower rubber rollers, and a plurality of pairs (eight pairs in the illustrated embodiment) of the feed rollers 11 are arranged in parallel so that the substrate 10 is held and conveyed in the direction of arrow A. ing.

Further, the substrate cleaning device 9 includes an upper roll brush 12a and a lower roll brush 12b that rotate in contact with the upper and lower surfaces of the substrate 10 being transported, respectively. A spray nozzle 13 is provided at the upper position of each upper roll brush 12a and at the lower position of each lower roll brush 12b.
The structure is such that pure water W as a cleaning liquid can be sprayed and supplied toward the cleaning liquid.

Note that the installation positional relationship between the roll brush 12 and the feed roller 11 is not limited to the illustrated example, and various other configuration examples are possible. Also,
The spray nozzle 13 may be installed at a position where it can spray the pure water W directly onto the surface of the substrate 10.

Next, next to the substrate cleaning section 7, a dehydrating/drying section 14 is continuously installed. As shown in FIG. 3, a pair of upper and lower double rollers 15 are provided near the entrance of the dehydrating and drying section 14 as a first dehydrating and drying means.
is provided. The double roller 15 is made of a porous resin with good water absorption properties, and is configured to come into contact with both the upper and lower surfaces of the cleaned substrate 10 and absorb moisture adhering to the surface.

Next to the double rollers 15, hot air nozzles 16 are provided as a second dehydrating and drying means in both upper and lower positions, and hot air is blown onto both the upper and lower surfaces of the substrate 10 sent out from the double rollers 15. ,
The structure is such that the substrate 10 can be dried.

A transfer roller 17 is provided next to the hot air nozzle 16. As shown in FIG. 4, the transfer roller 17 is constructed by having a plurality of rotating shafts 18 that are rotationally driven by a drive source (not shown), each provided with a pair of wheels 19. Each wheel 19
has a shape in which a large-diameter dish-shaped disk 19b is provided on the outside of a disk 19a, and the substrate 10 is configured such that both sides thereof are placed on the outer peripheral surface of the disk 19a and transported. has been done. Also, a pair of wheels 1
One of the wheels 9 and 19 can be slid freely in the axial direction and fixed at any position, so the width of the mounting 4 of the pair of wheels 19 with respect to the rotating shaft 18 is the width of the substrate 10 being transported. It can be set accordingly.

The double roller 15, hot air nozzle 16, and transfer roller 17 described above are covered by a case 20. The case 20 is in direct communication with the case 8 of the substrate cleaning section 7, so that the cleaned substrate 10 can be carried into the dehydration/drying process without being exposed to the outside air. Further, the dehydrating/drying section 14 is isolated from the outside world by the case 20, and the internal temperature, humidity, etc. are maintained at values suitable for dehydrating/drying work.

Next, next to the dehydrating/drying section 14, a cooling transfer section 21 is continuously arranged. As shown in FIG. 5, the cooling transfer section 21 includes the cases 8, 20
A guide roller 23 as a transfer guide means is provided in a case 22 similar to the above. The structure of the guide roller 23 is approximately the same as that of the transfer roller 17 provided in the dehydration/drying section 14, and the guide roller 23 carries the cleaned and dried substrate 10 transferred from the previous process.
The substrate 10 is configured so that it can be supported and transported only by both sides. In addition, the guide roller 23 is provided with a driving means 24, and the guide roller 23 is provided with a driving means 24.
3 is movable up and down while remaining horizontal, and is configured so that the feeding position to the next process can be arbitrarily adjusted.

The case 22 is directly connected to the case 20 of the dehydration/drying section 14 and isolates the cooling transfer section 21 from the outside world, so that the substrate 10 that has been dehydrated and dried is not exposed to the outside air. It is now ready to be transferred to the cooling process. The case 22 may be provided with an exhaust pipe 22a to be connected and communicated with an air conditioner (not shown) so that the air inside the case 22 can be forcibly sucked out. Furthermore, as will be described later, cooling air is supplied from the air conditioning equipment to the coating section 25 for the next step. Therefore, the cooling air is constantly circulated from the coating section 25 to the inside of the case 22, so that the substrate 10, whose temperature has increased due to dehydration and drying, is transported by the gas roller 23. It will be cooled down to the required temperature.

Next, next to the cooling transfer section 21, there is a coating section 2.
5 are arranged consecutively. As shown in FIG. 6, a saucer 26 is provided at the center of the coating section 25. The saucer 26 has the shape of a cylinder divided in half in the axial direction, and is positioned in a direction perpendicular to the feeding direction of the substrate 10 and the axis (longitudinal direction) and below the conveying surface of the guide roller 23. It is provided. A drive mechanism 27 is attached to the saucer 26 so that it can be moved downward from the above-mentioned position during cleaning or the like.

Further, inside the saucer 26, a thin film forming liquid 28 is provided.
(hereinafter abbreviated as liquid 28) is stored.

Although not shown, an automatic supply device for the liquid 28 is connected to the lower part of the saucer 26 via a supply pipe.
It is configured such that the amount of liquid in the saucer 26 is maintained at a constant minimum necessary amount. In addition, on both sides of the opening of the saucer 26, in order to suppress volatilization of the liquid,
A brim-shaped cover 26a is provided facing inward.

A coating roller 29 is provided above the saucer 26 . The coating roller 29 has a radius one size smaller than that of the saucer 26 , and a length in the axial direction is set to be slightly smaller than the longitudinal dimension of the saucer 26 . The coating roller 29 is disposed at a position such that a portion thereof enters inside the saucer 26,
A portion is immersed in the liquid 28. Further, the top of the outer peripheral surface of the coating roller 29 is configured to be slightly above the lower surface of the substrate 10 being transported. Further, the coating roller 29 is connected to a drive source (not shown) and is configured to be freely driven according to the work order. Furthermore, although the coating roller 29 is made of metal with a long life in this embodiment, it may also be made of ceramics or the like, or of resin or the like as long as it is not immersed in the liquid 28.

Above the coating roller 29, a presser roller 3 is provided.
0 is set. The presser roller 30 can be moved downward by a drive means (not shown), and the substrate 10 being transferred over the coating roller 29
The upper surface of the substrate 10 is held down by its own weight to prevent the substrate 10 from floating up.

The saucer 26, coating roller 29, presser roller 30, etc. are shielded from the outside world by a case 31, providing an optimal environment for the clean substrate 10, which has been adjusted to an appropriate temperature and is sent in from the previous process. The liquid 28 can be applied under certain conditions.
That is, an air conditioner (not shown) is connected to the case 31 via a feed pipe 31a, so that clean, dry, and cold air is always supplied into the case 31. Note that this dry cold air is transferred to the cooling transfer section 21 as described above.
case 20 of the dehydration/drying section 14 from inside the case 22 of
Inside, the liquid further flows into the case 8 of the substrate cleaning section 7.

Next, next to the coating section 25, a pooled liquid cut section 32 is disposed continuously. As shown in FIG. 6, inside a case 33 connected to the case 31 of the coating section 25, a discharge guide roller 34 is provided as a discharge side transfer guide means. The discharge guide roller 34 has substantially the same structure as the guide roller 23, and supports only both sides of the substrate 10, the lower surface of which is coated with a thin film of the liquid 28, and conveys it.

The front part of the discharge guide roller 34 protrudes from the case 33 and is located next to the coating roller 29 in the case 22 of the coating section 25, and a cutter 35 is provided below this part. ing. The cutter 35 includes a rectangular cutter plate 36 with an edge formed on its upper edge, and a drive device 37 for moving the cutter plate 36 up and down. Then, the cutter 35 is appropriately moved upward in synchronization with the operation of the guide roller 23, coating roller 29, discharge guide roller 34, etc., and comes into contact with the lower surface of the substrate 10 coated with the liquid 28. It is configured to remove excess liquid 28 accumulated on the lower surface of the rear end of the substrate 10.

Next, as shown in FIG. 7, a transfer heating section 38 is continuously disposed next to the reservoir cut section 32. The transfer heating section 38 has a conveyance roller 40 and a sending device 41 inside a case 39 . The conveyance roller 40 is connected to the guide roller 2
3, by contacting only both sides of the substrate 10,
It is configured to support the substrate 10 in a rollable manner.
Further, the feeding device 41 includes a feeding plate 41b that is guided by a fixed guide rod 41a and driven back and forth.

The inside of the case 39 is shielded from the outside world, and a heating means such as a heater (not shown) is provided inside the case 39 to heat and dry the applied liquid 28 to coat the substrate 10. A thin film is formed on the bottom surface.

Next, the operation of the configuration described above will be explained.

The substrate 10 is first sent to the substrate cleaning section 7. The substrate 10 is conveyed by the feed roller 11 while being moved by the upper and lower roll brushes 12a, 12b.
Both upper and lower surfaces are cleaned by pure water W sprayed from the spray nozzle 13.

Next, the cleaned substrate 10 is sent to the dehydration drying section 14. The substrate 10 is sandwiched from above and below by double rollers 15, and moisture adhering to the surface of the substrate 10 is absorbed. Continuously, hot air is blown onto both sides of the substrate 10 from the hot air nozzle 16 to evaporate the moisture remaining on the surface of the substrate 10. The dried substrate 10 is transported by a transport roller 17 and sent to the next process.

Next, the substrate 10 is transported by guide rollers 23 in the cooling transport section 21 .
Since the air in the case 22 of the cooling transfer section 21 is drawn to the external air conditioning equipment via the exhaust pipe 22a, the clean cooling air that the air conditioning equipment supplies to the adjacent coating section 25 is , always flows into the case 22 of the cooling transfer section 21. Then, the substrate 10, whose temperature has increased due to heating in the previous process, is cooled down to a temperature that does not adversely affect the liquid 28 by being exposed to this cooling air. In this step, the guide rollers 23 contact only the both sides of the cleaned and dried substrate 10 to guide and transport the substrate 10, so that the surface of the substrate 10 is not contaminated.

Next, the substrate 10, which has been adjusted to an appropriate temperature, is transferred to the coating portion 2.
Sent to 5. The coating roller 29 is connected to the saucer 26
Since the coating roller 29 rotates with a portion immersed in the liquid 28 contained in the coating roller 29, the liquid 28 always adheres to the surface of the coating roller 29.

The substrate 10 is fed to a position slightly lower than the top of the outer peripheral surface of the coating roller 29. Board 1
0 comes into contact with the outer peripheral surface of the coating roller 29, and then climbs onto the coating roller 29 with a slight inclination due to the driving force of the guide roller 23. Substrate 10
When the tip of the guide roller 23 reaches the top of the outer periphery of the coating roller 29, the operation of the guide roller 23 is temporarily stopped. Since the coating roller 29 continues to rotate,
The liquid 28 accumulates in the gap in front of the contact portion between the substrate 10 and the coating roller 29 due to surface tension.

Then, the presser roller 30 descends to press the top surface of the substrate 10, and the guide roller 23 is driven again to feed the substrate 10 onto the coating roller 29. At this time, the lower surface of the substrate 10 is brought into contact with the pool of liquid 28 that has formed in the gap between the substrate 10 and the coating roller 29, and
Since the liquid 28 is sent while sliding and pushed backward by the coating roller 29, the liquid 28 is uniformly and reliably applied to the lower surface of the substrate 10. Note that in this step, instead of applying pressure to the liquid 28 to transfer the substrate 10, the thin film is formed by running the substrate 10 over a pool of the liquid 28 formed by the application roller 29. ing. Therefore, at least the applicator roller 29 is placed in the saucer 26.
It is sufficient that there is enough liquid to partially submerge the liquid in saucer 2.
The automatic supply device may be adjusted so that the amount of liquid in 6 is maintained at a constant minimum required amount. Further, the saucer 26 is provided with a cover 26a,
Since the volatilization of the liquid 28 is suppressed, the liquid 28 can always be applied with a constant quality, and the yield of the liquid 28 is further improved, making it possible to realize a low-cost thin film forming operation.

Next, the substrate 10 is fed into the accumulated liquid cut section 32. The substrate 10 is sent by a discharge guide roller 34, and the cutter 3 is driven in synchronization with the operation of the discharge guide roller 34, etc.
5, the excess liquid 28 accumulated on the lower surface of the rear end of the substrate is removed.

Next, the substrate 10 is sent onto the transport roller 40 of the transport heating section 38 . The liquid 28 adhering to the lower surface of the substrate 10 is heated and dried to form a uniform thin film. Then, the substrate 10 on which the thin film is formed is sent out to the outside of the apparatus by the sending device 41.

Next, the embodiments described above are configured so that all operations from cleaning to heating are consistently performed inside the case, which is isolated from the outside world. Therefore, dust in the air, which is the biggest obstacle to thin film forming operations, does not become a problem, and high quality and uniform products can be manufactured.

[Effects of the Invention] As explained above, the thin film forming apparatus of the present invention has the following effects:
Each process section from the substrate cleaning section to the transfer heating section is arranged in a continuous manner, and the coating section is arranged so that it is partially immersed in the saucer containing the thin film forming solution and the thin film forming solution in the saucer. It is composed of a coating roller. Therefore, according to the present invention, a pool of the thin film forming liquid is formed in the gap near the contact portion between the substrate and the coating roller, and the substrate is fed over this pool while being in contact with it, thereby coating the liquid. This will have the following effects:

(1) The thin film forming liquid does not require a large amount in the device at once, and can be replenished into the saucer little by little, so there is less deterioration. Therefore, it can also be used as an unstable thin film forming solution in which an organic metal is dissolved in a low boiling point organic solvent.

(2) Since the deterioration of the thin film forming liquid can be reduced, the thin film forming liquid can always be applied in good condition, and a thin film with uniform quality can be formed.

(3) Since the thin film forming solution has little deterioration and the amount used can be kept to a minimum, manufacturing costs can be reduced.

(4) Since the liquid is applied from the bottom of the board, the thickness of the board can be freely selected and no adjustment is required.

(5) Each process part of the thin film forming apparatus is isolated from the outside world by the case, eliminating problems caused by outside temperature and humidity, as well as dirt and dust.
This has the effect of providing equipment that can produce uniform products of high quality.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the overall configuration of the present invention, FIG. 2 is a sectional view showing the main parts of the substrate cleaning section, FIG. 3 is a sectional view showing the main parts of the dehydration drying section, and FIG. 4 teeth,
A front view of the transfer roller, FIG. 5 is a sectional view showing the main parts of the cooling transfer section, FIG. 6 is a sectional view showing the main parts of the coating section and the accumulated liquid cutting section, and FIG. 7 is the transfer heating section. FIG. 8 is a side view showing an example of the configuration and usage of a conventional roll coater. 7...Substrate cleaning section, 9...Substrate cleaning device, 10...
...Substrate, 11...Feed roller as a transfer means,
14... Dehydration and drying section, 15... Double roller as dehydration and drying means, 16... Hot air nozzle as dehydration and drying means, 21... Cooling transfer section, 23... Guide roller as transfer guide means, 25... ...Application part, 26...Saucer, 28...Thin film forming liquid (liquid),
29...Applying roller, 32...Reservoir liquid cut section,
34...Discharge guide roller as discharge side transfer guide means, 35...Cut, 38...Transfer heating section,
W...Pure water as a cleaning liquid.

Claims (1)

[Scope of Claims] 1. A substrate cleaning section equipped with a substrate transfer means and a substrate cleaner; a dehydration drying section equipped with a dehydration drying means for removing the cleaning liquid from the cleaned substrate; and both sides of the substrate. A cooling transfer section having a transfer guide means that contacts only the coating material, a saucer for storing a thin film forming liquid, and a coating roller disposed so as to be partially immersed in the thin film forming liquid in the saucer. a coating section configured to temporarily stop the transfer guide means when the substrate comes into contact with the deposition roller and to collect the thin film forming liquid on the back surface of the substrate by the rotating coating roller; A pooled liquid cutting section with a vertically movable cutter and a transfer heating section for drying the thin film of the transferred substrate are arranged continuously inside the case while being isolated from the outside world. A thin film forming device featuring: 2. The thin film forming apparatus according to claim 1, wherein the coating roller of the coating section is a metal roller.