JP2656317B2 - Organic thin film manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an apparatus used for producing an organic thin film by the Langmuir-Blodgett method.

(Prior Art) In recent years, research on organic thin films represented by Langmuir-Blodgett films (hereinafter abbreviated as LB films) has been actively conducted for the purpose of application to various new functional electronic devices. In such a device, in a uniform and extremely thin film, the orientation of a functional molecule containing a dye or the like in the film, a laminated structure,
A predetermined function can be realized only by controlling the intermolecular distance and the like.

In a normal LB film forming method, an amphiphilic organic molecule having a portion having a higher hydrophilicity and a portion having a higher hydrophobicity in a molecule is developed on the water surface and is developed so as to exhibit a predetermined surface tension. After forming a monolayer on the water surface in which the molecules are packed densely by compressing the area, the predetermined substrate is moved vertically or horizontally with respect to the monolayer to form a monolayer on the substrate. Transfer the film to form a cumulative film.

The film forming apparatus for performing the above-described film forming operation is basically composed of a water tank for obtaining a water surface for developing a monomolecular film, a movable barrier for changing a developed area of the molecule, and a surface on the water surface. It comprises a surface pressure gauge for detecting pressure and an accumulating mechanism for vertically moving the substrate to transfer the monomolecular film onto the substrate. However, with conventional film forming equipment, simply reducing the area of the water tank to shorten the compression time of the monomolecular film, or installing a substrate or surface pressure gauge at the end of the water tank to increase the effective cumulative area, originally provides good quality. The optimization as an apparatus for forming a large accumulation film has not been performed. For this reason, in the study of the present inventors, standard stearic acid (cadmium salt) was used using a commercially available film forming apparatus.
It has been revealed that a cumulative film obtained by forming a molecule has many defects (Synthetic Metals, Vol. 18, 80
Pp. 3-807 and 809-814, 1987), and it has become common knowledge in later academic circles that the LB film is defective.

The above-mentioned occurrence of defects in the LB film is due to the fact that a predetermined surface pressure is not applied to the monomolecular film on the water surface near the substrate at the time of film formation. This is because the conventional manufacturing apparatus has the following problems.

First, most molecules, with some exceptions, behave as a viscoelastic fluid when a monomolecular film is formed on the water surface, and are not uniformly compressed when the area is compressed by the barrier, and the surface pressure distribution is not uniform. Is shown. For this reason, the surface pressure at the center of the water surface does not reach the predetermined value or the surface pressure near the barrier becomes abnormally high depending on the place where the surface pressure gauge (especially the detector) is installed, and the monomolecular film is stabilized. Problems such as not doing so. In addition, there is a problem that the position of the substrate lowered relative to the monomolecular film is different from the value set by the detector of the surface pressure gauge. Secondly, when the monolayer on the water surface is moved down by lowering the substrate, the surface pressure of the monolayer near the substrate is lowered by moving the substrate. Pressure is almost 0dyn / cm (same surface tension as water surface)
It falls until it becomes. In such a state, the monomolecular film on the water surface immediately before being transferred to the substrate cannot be said to be a densely packed monomolecular film, and may cause structural disorder or defects. This is because the surface pressure drop near the substrate is not correctly detected by the detector of the surface pressure gauge that should be originally observed, and as a result, the compression control drive unit does not follow and move. Third, when the monolayer is transferred to the substrate under the conditions described above, the surface pressure must be maintained by compressing the barrier by the reduced area of the monolayer on the water surface. However, as the viscoelasticity of the monomolecular film increases, the responsiveness of recovery of the surface pressure near the substrate due to the compression of the barrier deteriorates.

Therefore, with the conventional organic thin film manufacturing apparatus, the uniformity of the surface pressure distribution of the monomolecular film on the water surface and the surface pressure near the substrate during accumulation are not well controlled, and it is not possible to manufacture an excellent organic thin film. was there.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned conventional problems, and aims to provide an organic thin film manufacturing apparatus capable of manufacturing an organic thin film having a uniform structure and no defects. Things.

[Constitution of the Invention] (Means for Solving the Problems) The present invention relates to a water tank having two partition walls for dividing two sides in one direction of a monomolecular film of an amphiphilic organic molecule to be developed, A movable barrier for changing the development area of the monolayer on the water surface between the partitions, and defining two sides of the monolayer perpendicular to the partitions, and a surface pressure gauge for detecting the surface pressure of the monolayer And an apparatus for manufacturing an organic thin film, comprising: an accumulating mechanism for driving the substrate to accumulate the monomolecular film on a predetermined substrate, wherein the partition wall has a portion in contact with a water surface in a direction perpendicular to the water surface. An organic thin-film manufacturing apparatus having a function of continuously moving.

As the partition wall, for example, a rotating cylindrical body,
Examples thereof include a sheet wound around a cylindrical support provided near the water surface and moving in a direction perpendicular to the water surface, and a rotating cylindrical body having helical irregularities formed on the surface. Such a partition has a tangential velocity on the water surface of 0.01 to
It is desirable to exercise so as to be 100 mm / min. The speed of the partition walls does not need to be always constant during a series of film forming operations from compression to accumulation.

(Action) The present inventors have completed the invention based on the following findings. That is, the present inventors have examined the compressive behavior of a molecule having a high viscoelastic property on the water surface, and as a result, the following has become clear. First, when a monomolecular film having high viscoelasticity is compressed, the surface pressure increases near the barrier to be compressed. If the compression is continued as it is, the region where the surface pressure becomes high propagates forward of the barrier, but when the moving distance of the barrier becomes long, the monomolecular film near the barrier collapses. Second, in the compression process, the surface pressure increases more rapidly near the barrier ribs than at the center. Third, FIG. 14 (a),
(B) As shown in (b), when a monomolecular film is formed on the water surface partitioned by two partition walls 1a and 1b and movable barriers 2a and 2b orthogonal to the inside of the water tank, and one barrier 2b is moved and compressed. When the flow process of the monomolecular film on the water surface is visualized by using the hydrophobic fine powder 3, the flow of the monomolecular film is significantly inhibited in the vicinity of the partition walls 1a and 1b of the advancing barrier 2b. Reference numeral 4 in FIG. 14 denotes a detector of the surface pressure gauge. From these results,
It has been clarified that the surface pressure of the molecules having high viscoelasticity is significantly increased because the flow of the monomolecular film is inhibited at the partition wall near the barrier when the molecules having high viscoelasticity are compressed. It is considered that this is because the monomolecular film whose surface pressure has increased adheres to the partition walls.

On the other hand, the present inventors have studied in detail the cumulative behavior of the monomolecular film on the water surface on the substrate, and have obtained the following knowledge. That is, when the monomolecular film on the water surface is accumulated by raising the substrate immersed under the water surface, the accumulation ratio becomes zero when the contact angle of the substrate with respect to pure water is equal to or more than a certain critical value (Θc-up). Conversely, when the substrate is lowered to accumulate the monomolecular film on the water surface, the contact angle of the substrate with respect to pure water has a critical value (Θ
The accumulation ratio becomes zero below c-down). Specifically, the monomolecular film does not adhere to the substrate with high hydrophobicity when the substrate rises, and does not adhere to the substrate with high hydrophilicity when the substrate descends.

Based on the above findings, the present invention can avoid the adhesion of the film to the partition, which causes the surface pressure distribution when the monomolecular film is compressed, by providing the function of continuously moving the partition in the vertical direction. That is, in the case of a hydrophobic partition wall, it is moved in an ascending direction at the boundary with the water surface during the compression of the monomolecular film, while in the case of the hydrophilic partition wall, it is moved at the boundary with the water surface during the compression of the monomolecular film. When the monomolecular film is moved in a descending direction, the film does not adhere to the partition walls even if the surface pressure of the monomolecular film increases, and the monomolecular film advances along the partition walls together with the barrier compression. The speed at which the partition wall is moved at this time is desirably within a range that satisfies the above-mentioned critical condition of the contact angle with respect to the adhesion of the monomolecular film. The effect of forming a boundary layer between molecular films is also expected. Therefore, the conditions may be set within a range that does not impair the stability of the monomolecular film.

In the above-described operation, the case where the partition wall is moved in the direction perpendicular to the water surface has been described. However, a rotating cylindrical body having helical irregularities formed on the surface is used as the partition wall, and this cylindrical body is attached to a film. By rotating the concavities and convexities so as to advance in the compression direction of the barrier at the boundary of the water surface under the condition where the water does not occur, a velocity component in the compression direction can be given to the water itself at the partition boundary. As a result, the effect of inhibiting the adhesion of the monomolecular film to the partition walls can be further enhanced, and
The flow of water and the monolayer on the water surface can be promoted to achieve a further effect on the uniform compression. Further, in the conventional apparatus, the compression speed had to be extremely slow to control the generation of the π distribution, but in the manufacturing apparatus of the present invention, uniform compression is possible even at a higher speed, and the film is formed. It also has the effect of shortening the time.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. In the manufacturing apparatuses of FIGS. 7 and 11 used in the third and fourth embodiments, the same members as those of the manufacturing apparatus shown in FIG. 1 used in the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

Embodiment 1 FIG. 1 is a schematic perspective view showing an organic thin film manufacturing apparatus according to Embodiment 1 of the present invention. Numeral 11 in the figure denotes a water tank whose inner surface is coated with a fluororesin film. This aquarium
The column 11 is provided with, for example, cylindrical members 12a and 12b each having a diameter of, for example, 20 mm and serving as two partition walls for partitioning two sides in one direction of a monomolecular film of an amphiphilic organic molecule to be developed. These cylinders 12a, 12b are rotatably supported at both ends by a suspended support plate 13, and can be rotated in opposite directions by a drive source (not shown). The surface of each of the cylindrical bodies 12a and 12b is covered with a fluororesin.
On each of the cylindrical bodies 12a and 12b, movable barriers 14a and 14b for dividing the other two sides of the monomolecular film are provided.
They are arranged movably in the axial direction of a and 12b. Arms 15a and 15b are connected to ends of the barriers 14a and 14b, respectively, and the other ends of the arms 15a and 15b are connected to a drive mechanism (not shown). Further, the cylindrical bodies 12a, 12b
A detector 16 of a surface pressure gauge is arranged near the water surface of the water tank 11 defined by the movable barriers 14a and 14b. An accumulation mechanism (not shown) for driving the substrate is provided near the side wall of the water tank 1 so as to accumulate the monomolecular film on a predetermined substrate.

In the manufacturing apparatus having such a configuration, the cylindrical bodies 12a and 12b
And the water surface of the water tank 11 partitioned by the movable barriers 14a and 14b
The stearic acid dissolved in water containing Cl ₃ [(Al ³⁺ ) = 1 × 10 ⁻⁵ M] is developed, and the cylinders 12a and 12b are moved upward in the water tank 11 side where the molecules are developed (the cylinder). The body 12a was rotated in a counterclockwise direction and the cylindrical body 12b was rotated in a clockwise direction) at an angular velocity of 0.5 ° / sec. At this time, the speed at which the cylinders 12a and 12b cross the water surface is about 5 mm / min. In this state, two movable barriers 1
4a and 14b were moved close to each other to compress the developed monomolecular film of stearic acid.

In the operation described above, the hydrophobic fine powder 17 was dispersed in the form of equidistant stripes on the water surface where the monomolecular film was developed before compression, and the flow pattern in the compression process was observed. The result shown in FIG. 2 was obtained. I got FIG. 3 shows that, similarly to the conventional method, the hydrophobic fine powder 3 is equidistantly striped on the water surface where the monomolecular film is spread while the partition walls (cylindrical bodies) 1a and 1b in the water tank are fixed without rotating. 5 shows a flow pattern when the particles are dispersed in a shape and compressed by the movable barriers 2a and 2b. 2 and 3, it can be seen that by rotating the cylinders 12a and 12b as in the manufacturing apparatus of the first embodiment, it is possible to alleviate the inhibition due to the film adhesion to the cylinders 12a and 12b. .

In addition, when the surface pressure of the monomolecular film during the compression process was measured at multiple points in the above-described operation, the results shown in FIG. 4 were obtained. FIG. 4 shows the cylindrical bodies 12a and 12b and the barrier 14
The surface pressure measurement points A to D in the developed region of the monomolecular film partitioned by a and 14b and the characteristic line of the area-surface pressure at the measurement points A to D are shown. As is apparent from FIG. 4, the surface pressure distribution is generated in the monomolecular film by the compression by the movable barrier. However, in the apparatus of the first embodiment, the degree of the surface pressure distribution is remarkably improved as compared with the conventional apparatus. You can see that it is.

Example 2 In the manufacturing apparatus of Example 2, the above-described cylindrical body shown in FIG.
Glass rods having hydrophilic surfaces were used as 12a and 12b.

In the manufacturing apparatus having such a configuration, the cylindrical bodies 12a and 12b
And the water surface of the water tank 11 partitioned by the movable barriers 14a and 14b
The stearic acid dissolved in water containing [Cl ₃ ] [(Al ³⁺ ) = 1 × 10 ⁻⁵ M] is developed, and the cylinders 12 a and 12 b are diverted downward on the side of the water tank 11 where the molecules are developed (the cylinder). The body 12a was rotated in a clockwise direction and the cylindrical body 12b was rotated in a counterclockwise direction) at an angular velocity of 0.5 ° / sec. At this time, the speed at which the cylinders 12a and 12b cross the water surface is about 5 mm / min. In this state, the two movable barriers 14a and 14b were moved so as to approach each other to compress the developed monomolecular film of stearic acid.

In the operation described above, the hydrophobic fine powder 17 was dispersed in the form of equidistant stripes on the water surface where the monomolecular film was developed before compression, and the flow pattern in the compression process was observed. The result shown in FIG. 5 was obtained. I got From the comparison between FIG. 5 and FIG. 3 showing the flow pattern of the conventional method, the film on the cylindrical bodies 12a and 12b is rotated by rotating the cylindrical bodies 12a and 12b as in the manufacturing apparatus of the second embodiment. It can be seen that inhibition due to adhesion can be reduced.

When the surface pressure of the monomolecular film during the compression process was measured at multiple points in the above-described operation, the results shown in FIG. 6 were obtained. FIG. 6 shows the cylindrical bodies 12a and 12b and the barrier 14
The surface pressure measurement points A to D in the developed region of the monomolecular film partitioned by a and 14b and the characteristic line of the area-surface pressure at the measurement points A to D are shown. As is apparent from FIG. 6, the surface pressure distribution is generated in the monomolecular film by the compression by the movable barrier. However, in the apparatus of the second embodiment, the degree of the surface pressure distribution is remarkably improved as compared with the conventional apparatus. You can see that it is.

Third Embodiment FIG. 7 is a schematic perspective view showing an organic thin film manufacturing apparatus according to a third embodiment of the present invention. In this manufacturing apparatus, two columnar supports 18a, 18b parallel to each other are arranged in a part of the water tank 11, and the respective supports 18a, 18b serve as partitions having substantially the same width as the supports 18a, 18b. Fluororesin sheets 19a and 19b are wound half-turn from below, for example, four rotating rollers 20a to 23a,
In 20b to 23b, each of the sheets 19a and 19b is a respective support 18a and 1
It has a structure in which it is wound just below 8b so as to move vertically. Arms 24a and 24b extending in the vertical direction are connected to ends of the barriers 14a and 14b, respectively, and the other ends of the arms 24a and 24b are connected to a drive mechanism (not shown).

In the manufacturing apparatus having such a configuration, the columnar support 18
a, 19b, and the movable barrier 14
Water containing AlCl ₃ on the water surface of the water tank 11 partitioned by a and 14b [(A
l ³⁺ ) = 1 × 10 ⁻⁵ M], and dissolve the stearic acid, and apply the sheets 19a and 19b to rotating rollers 20a to 23a and 20b to 2
The molecule was wound so as to move in the upward direction on the side of the water tank 11 where the molecules were developed by 3b. At this time, the speed at which the sheets 19a and 19b cross the water surface is about 5 mm / min. In this state, the two movable barriers 14a and 14b were moved so as to approach each other to compress the developed monomolecular film of stearic acid.

In the operation described above, the hydrophobic fine powder 17 was dispersed in the form of equidistant stripes on the water surface on which the monomolecular film was developed before compression, and the flow pattern in the compression process was observed. The result shown in FIG. 8 was obtained. I got Comparison between FIG. 8 and FIG. 3 showing the flow pattern of the conventional method described above shows that the sheets 19a and 19b as partition walls are moved in the direction perpendicular to the water surface as in the manufacturing apparatus of the third embodiment. It can be seen that inhibition due to film adhesion to the sheets 19a and 19b can be reduced.

When the surface pressure of the monomolecular film during the compression process was measured at multiple points in the above-described operation, the results shown in FIG. 9 were obtained. FIG. 9 shows a sheet wound around a cylindrical support.
Surface pressure measurement points A to D in the development region of the monomolecular film partitioned by 19a, 19b and barriers 14a, 14b, and measurement points A to D
2 shows a characteristic line of the area-surface pressure at. As is apparent from FIG. 9, the surface pressure distribution is generated in the monomolecular film with the compression by the movable barrier. However, in the apparatus of the third embodiment, the degree of the surface pressure distribution is remarkably improved as compared with the conventional apparatus. You can see that it is.

Embodiment 4 FIG. 10 is a schematic perspective view showing an apparatus for producing an organic thin film according to Embodiment 4 of the present invention. FIG. 11 is an enlarged perspective view of a cylindrical body having spiral irregularities formed on the surface of FIG. FIG. This manufacturing apparatus is composed of two fluororesin-coated cylindrical bodies 26a and 26b having spiral irregularities 25a and 25b made of fluororesin formed on the surface thereof in a water tank.
The structure is such that it is arranged parallel to each other on a part of 11. The spiral unevenness 25a is inclined downward and to the left with respect to the axis of the cylindrical body 26a, and the spiral unevenness 25b is
Of each spiral 25a, 2
The spiral directions of 5b cross each other.

In the manufacturing apparatus having such a configuration, two cylindrical bodies 26 having spiral irregularities 25a and 25b made of fluororesin are formed on the surface.
The stearic acid dissolved in water [(Al ³⁺ ) = 1 × 10 ⁻⁵ M] containing AlCl ₃ is developed on the water surface of the water tank 11 defined by the a, 26b and the movable barriers 14a, 14b. 26a and 26b are rotated at a speed of 0.5 ° / sec in a direction of ascending on the water tank 11 side where the molecules are developed. At this time, the speed at which the cylinders 26a and 26b cross the water surface is about 5 mm / min. Further, the advance speed of the spiral unevenness 25a, 25b at the boundary of the water surface is substantially the same as the advance speed of the barrier 14a. In this state, by moving one movable barrier 14a toward the other fixed barrier 14b, the developed monomolecular film of stearic acid was compressed.

In the above-described operation, the hydrophobic fine powder 17 was dispersed in a uniform stripe pattern on the water surface where the monomolecular film was developed before compression, and the flow pattern in the compression process was observed. I got From the comparison between FIG. 12 and FIG. 3 showing the flow pattern of the conventional method described above, a cylindrical body 26a having spiral irregularities 25a and 25b formed on the surface as a partition as in the manufacturing apparatus of the fourth embodiment, It can be seen that by rotating 26b, inhibition due to film adhesion to the cylindrical bodies 26a and 26b can be alleviated.

In addition, when the surface pressure of the monomolecular film during the compression process was measured at multiple points in the above-described operation, the results shown in FIG. 13 were obtained. FIG. 13 shows surface pressure measurement points A to D in the development region of the monomolecular film partitioned by the cylindrical bodies 26a and 26b having the spiral irregularities 25a and 25b formed on the surface and the barriers 14a and 14b, and the measurement. The characteristic line of area-surface pressure at points A to D is shown. As is apparent from FIG. 13, in the apparatus of the fourth embodiment, the rotation of the cylindrical bodies 26a and 26b on which the spiral irregularities 25a and 25b are formed and the barrier 14a of the spiral irregularities 25a and 25b at the boundary of the water surface. It can be seen that, by performing the forward movement at the same speed in the direction, the generation of the surface pressure distribution of the monomolecular film due to the compression of the movable barrier can be remarkably improved as compared with the conventional apparatus.

[Effects of the Invention] As described in detail above, according to the present invention, not only can a monomolecular film on the water surface be formed uniformly and at high speed, but also a decrease in surface pressure due to the flow of the compressed film during accumulation can be quickly compensated,
An apparatus for manufacturing an organic thin film capable of manufacturing an organic thin film having a uniform structure and no defects can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an apparatus for producing an organic thin film according to the first embodiment of the present invention, and FIG. 2 is a view showing a state where the monomolecular film developed by the production apparatus according to the first embodiment is compressed. FIG. 3 is a plan view showing a flow pattern of the hydrophobic fine powder, FIG. 3 is a plan view showing a flow pattern of the hydrophobic fine powder on the monomolecular film when the monomolecular film developed by the conventional manufacturing apparatus is compressed, FIG. 4 is a diagram showing the surface pressure measurement points in the developed region of the partitioned monomolecular film when multi-point measurement of the surface pressure of the monomolecular film in the compression process in Example 2 and the area-surface at these measurement points FIG. 5 is an explanatory view showing pressure characteristic lines, FIG. 5 is a plan view showing a flow pattern of hydrophobic fine powder on the monomolecular film when the monomolecular film developed by the manufacturing apparatus of Example 2 is compressed, FIG. 6 is a section when the surface pressure of the monomolecular film in the compression process in Example 2 was measured at multiple points. FIG. 7 is an explanatory view showing surface pressure measurement points in the developed region of the monomolecular film and characteristic lines of area-surface pressure at these measurement points. FIG. 7 is a schematic diagram showing an organic thin film manufacturing apparatus according to a third embodiment of the present invention. FIG. 8 is a plan view showing a flow pattern of the hydrophobic fine powder on the monomolecular film when the monomolecular film developed by the manufacturing apparatus of Example 3 is compressed, and FIG. Showing the surface pressure measurement points in the developed region of the partitioned monomolecular film and the characteristic line of area-surface pressure at these measurement points when multi-point measurement of the surface pressure of the monomolecular film in the compression process is performed FIG. 10, FIG. 10 is a schematic perspective view showing an apparatus for producing an organic thin film of Example 4 of the present invention, FIG. 11 is an enlarged perspective view showing a cylindrical body having spiral irregularities formed on the surface of FIG. FIG. 12 shows the hydrophobic fine powder on the monomolecular film when the monomolecular film developed by the manufacturing apparatus of Example 4 was compressed. FIG. 13 is a plan view showing a flow pattern, and FIG. 13 is a diagram showing the surface pressure measurement points in the developed region of the partitioned monomolecular film when performing multipoint measurement of the surface pressure of the monomolecular film in the compression process in Example 4. FIG. 14 (a) is an explanatory diagram showing a characteristic line of the area-surface pressure at the measurement point.
(B) is a plan view showing a flow pattern of a hydrophobic fine powder in a process of compressing a monomolecular film developed by a conventional manufacturing apparatus. 11… Aquarium, 12a, 12b, 26a, 26b …… Cylindrical body, 14a, 14b
... movable barrier, 16 ... detector of surface pressure gauge, 17 ... hydrophobic fine powder, 18a, 18b ... cylindrical support, 19a, 19b ... sheet, 25a, 25b ... spiral unevenness.

Claims (4)

(57) [Claims] 1. A water tank having two partition walls for partitioning two sides of a unimolecular film of an amphiphilic organic molecule to be developed in one direction, and a developed area of a monomolecular film on a water surface between the partition walls is changed. And a movable barrier for partitioning two sides of the monomolecular film orthogonal to the partition wall, a surface manometer for detecting the surface pressure of the monomolecular film, and accumulating the monomolecular film on a predetermined substrate. An organic thin film manufacturing apparatus having an accumulation mechanism for driving the substrate to cause the partition to have a function of continuously moving a portion in contact with a water surface in a direction perpendicular to the water surface. Organic thin film manufacturing equipment. 2. The apparatus for producing an organic thin film according to claim 1, wherein the partition comprises a rotating cylindrical body. 3. The organic thin film according to claim 1, wherein the partition is formed of a sheet wound around a cylindrical support provided near the water surface and moving in a direction perpendicular to the water surface. Manufacturing equipment. 4. The partition according to claim 1, wherein the partition comprises a rotating cylindrical body having helical irregularities formed on a surface thereof.
An apparatus for producing an organic thin film according to the above.