JPS60193328A - Film forming method - Google Patents

Abstract

PURPOSE:To improve a yield of continuous cumulation of molecules for film forming, by providing with liquid-flow generating means in the liquid bath for expanding the film forming molecules, and by controlling a surface density of the film forming molecules by changing the liquid-flow when a desired monomolecular cumulated film is formed. CONSTITUTION:On forming a thin film bearing optical functions which a logical device, a memory device and a photoelectric converting device, etc. have, the thin film consisting of organic molecules is formed with a monomolecular cumulation method. Water from a water flow generating means 7 is flowed into a water bath 3, the water surface is dammed by a barrier 8 being placed on the water bath 3 so as to overflow the excess water, and organic solution is dripped onto the water surface being dammed to form a film. That is to say, the solution of 0.1ml in which stearic acid is being melted in a solvent of chloroform at a rate of 1X10<-3>M/l is dripped onto the water surface. The width of the water bath 3 at the surface pressure producing area 11 including the dripping area 9 is made narrow, for example 2cm, and the width of the cumulating area 10 is made wide, for example 20cm, to allow flow rates of these areas to change into about 2cm/sec from 20cm/sec. In this way, the cumulation yield can be improved to 50-100%.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a method for producing a thin film that is a functional part of a semiconductor or an optical device, and in particular, a method for producing a thin film that is a functional part of a semiconductor or an optical device, and in particular, a method for manufacturing a thin film that is a functional part of a semiconductor or optical device, and in particular, a method for manufacturing a thin film that is a functional part of a semiconductor or an optical device. The present invention relates to a method for producing an LB film using.

BACKGROUND ART Conventionally, the use of materials in the semiconductor technology field and the optical technology field has mainly focused on inorganic materials that are relatively easy to handle. One reason for this is that technological progress in the field of organic chemistry has lagged significantly behind that in the field of inorganic materials.

However, recent technological advances in the field of organic chemistry have been remarkable, and it is said that the development of materials for inorganic substances has almost reached its limit. Therefore, there is a demand for the development of functional organic materials as new functional materials that surpass inorganic materials. The advantages of IR materials are that they are inexpensive, easy to manufacture, and highly functional.On the other hand, organic materials have recently overcome their heat resistance and mechanical strength, which were previously thought to be inferior. are being born one after another. Based on this technical background, some of the functional parts (mainly thin film parts) of IC devices such as logic elements, memory elements, photoelectric conversion elements, and optical devices such as microlens Φ arrays and guiding waveguides have been developed. Or, from the proposal to replace the conventional inorganic thin film with an organic thin film, or even from molecular electronic devices and bio-related materials in which 1' organic molecules have functions such as logic elements and memory elements. Several research institutes have recently announced proposals to create logic devices (such as bio-Φ chips) that will

When creating the various devices mentioned above using such organic materials? The diI model is based on the known single molecule accumulation method, namely Langmuir Φ Blogett l-? ), (LB?),)
can be formed by

The LB method refers to the parent tree group 1a and the hydrophobic base group 1a in FIG.
1; A single molecule 1 composed of 1b, that is, a constituent substance 11, is dissolved in a volatile solvent such as benzene or chloroform, and dropped onto the water surface surrounded by a frame 4 arranged in a water tank 3, The monomolecular film left on the water surface after the solvent evaporates (
At this point, the gas film (2) is transformed into a solid film by reducing the area surrounded by the frame 4 and increasing the areal density of the monomolecular film 2, and this is transformed into a solid film by a vertical dipping method or a horizontal pricking method (not shown). This is a method of transferring it to a substrate.

However, according to this method, the area of the monolayer on the water surface decreases by the amount of the monolayer transferred onto the substrate. In other words, since the monomolecular film (solid film) on the water surface is required to be uniform, if the monomolecular film is continuously transferred onto the substrate while keeping its areal density constant, , the area surrounded by the frame gradually decreases and approaches O, so
There is naturally a limit to the number of times it can be transferred.

<Disclosure of the Invention> The purpose of the present invention is to solve the above-mentioned problems, and for this purpose, the surface pressure of a monomolecular film is controlled by a liquid flow so as to obtain a desired areal density. This makes it possible to perform continuous accumulation of medium molecular films.

The principle of the present invention will be explained below with reference to the iS2 diagram.

When the monomolecular film 2 is spread on the surface of water with a certain flow rate, the monomolecular film 2 moves in the direction of the water flow (in the direction of the arrow) due to the attraction between the molecules constituting the middle molecular film 2 and the water. It is pulled with a certain force. At this time, if there is a barrier 8 in the path of the monomolecular film 2 that can block only the movement of the monomolecular film 2 without affecting the flow of water, the monomolecular film 2 will act against the barrier with a certain force. It is pressed against 8. That is, this shows that the force with which the single molecules M 2 press against the barrier 8, in other words, the surface pressure of the jli molecular film 2, can be easily controlled by changing the water flow rate. The present invention is characterized by applying this principle.

<BEST MODE FOR CARRYING OUT THE INVENTION> Hereinafter, uninvented embodiments will be described with reference to the drawings. Note that in each drawing, the same reference numerals represent the same structural members and have the same functions.

First, a first embodiment will be described with reference to FIG. Stearin in the solvent chloroform at 1 x 10-'M#! 0.1 ml of the solution dissolved at a rate of 20 cm/s, e
c When a drop is applied and developed in an area 9 upstream of the barrier 7 wall 8 (hereinafter referred to as the dripping area 9) on the water surface flowing at a speed in the direction of the arrow, the water surface surrounded by the barrier 8 is An I'11 molecular film 2 of about 120 crn'' was formed on the middle molecular film 2. When the surface pressure of the middle molecular film 2 was measured using a surface pressure measuring device (not shown), it showed a value of 24 dyne/Cnl.
It was confirmed that the monomolecular film 2 formed a desired solid state. Furthermore, when the velocity was varied in the range of 15 to 25 cm/sec, it was confirmed that the surface pressure changed approximately in proportion to this, and it became clear that the surface pressure could be controlled by the flow velocity. Moreover, at this time, the dripping fineness is also 0.05 to 0.
When the surface pressure was varied within the range of 3ff1i, it was confirmed that the surface pressure also became feminized in proportion to this. In other words, it has become clear that the surface pressure can also be controlled using a dropper.

On the other hand, a region 10 near the barrier 8 (hereinafter, cumulative region 10
It is called. ), when Cli molecules j1 were accumulated on the substrate by the vertical dipping method, a good film with an accumulation rate of 90 to almost 100% could be obtained.

Then, while controlling the flow rate so that the surface pressure remains constant,
In addition, the accumulation operation is repeated while the monomolecular film 2 is transferred to the substrate in the accumulation region IO and the decrease is compensated for by the dropping of the film constituent material in the dropping region 9. As a result, continuous accumulation, which was difficult with conventional devices, is facilitated. was able to achieve this.

Next, a second embodiment will be explained according to FIG.

The nut flow side is a modification of the first embodiment with some improvements. That is, in the first embodiment, in the accumulation region lO, the flow of water is disturbed by the substrate (not shown) that is submerged in water in the case of accumulation by the vertical immersion method, as well as the barrier 8, and the monomolecular film 2 is bent. kf is not acceptable because the surface pressure, which should be constant, fluctuates temporarily.

Therefore, in this embodiment, the first embodiment is improved by varying the depth of the water tank and slowing down the water flow (flow velocity) in the 1° accumulation area. Specifically, the drip area 9
The depth of the water tank in the region 11 (hereinafter referred to as surface pressure forming region 11) that forms the surface pressure of the monomolecular film 2 including I made it deep. As a result, 1 surface pressure formation area + 1
Even if the flow velocity at is 20cm/see, the cumulative area is 10
The flow rate was about 171 degrees, and when the monomolecular film was accumulated on the substrate, the yield was 2 in the first example.
It improved from 0 to 60% to 50 to 100%.

Next, a third embodiment will be described with reference to FIG.

This embodiment is a modification of the second embodiment, and is an improvement over the first embodiment by varying the width of the water tank and slowing down the flow velocity in the accumulation region 10. Specifically, the width of the water tank in the surface pressure forming area 11 including the dripping area 9 was narrowed to 2 cm, and the width of the water tank connected to the accumulation area 10 was widened to 20 cm.As a result, the surface pressure forming area 1
Even if the flow rate in Example 1 is 20 cm/sec, the flow rate in the accumulation region 10 is about 1/10. %, but this has improved to 50 to ioo%.Next, the fourth embodiment will be described with reference to FIGS. 6(a) and (b).

In this embodiment, a single aquarium is partitioned off only near the water surface by a plurality of (five in this embodiment) fan-shaped barriers 8.
Hereinafter, the partitioned areas will be referred to as blocks. ), water flows into each block from near the center toward the outer periphery. The apparatus according to this embodiment has the following features regarding the ability to accumulate the monomolecular film 2 on the substrate and the ease of continuous accumulation.
This is similar to the first embodiment.

Furthermore, a unique feature of the non-examples is that it is possible to easily accumulate different types of medium molecules (heterostructure). That is, each block is made of different materials in advance? 11
The molecular film was developed on the water surface, and the monomolecular film was accumulated on the substrate using the tonnai dipping method in a certain block.
By repeating the same operation in another block, it was possible to easily form a hetero-accumulated film (the constituent molecules of the middle molecular film differ in the direction of accumulation). At this time, it is possible to move between blocks in the gas phase or in the aqueous phase, so for example, in a heterojunction of a film that forms a Y-type film, hydrophobic groups are also present between hydrophilic groups. It was also possible to freely set the rules between comrades.

Next, a fifth embodiment will be explained according to FIG. 7.

In this embodiment, the outflow water is circulated in the previous embodiment.
It is characterized by the fact that water is reused by letting it drain and returning it to the aquarium. In Fig. 7, Pyrex glass tubes are used for most of the wj return path 12,
Further, the water accumulated in the water tank 13 is pumped out by a pump 14, and the flow rate is controlled by a gate valve 15.

In this way, by circulating the outflowing water, there is no need for a system to replenish lost water, and the entire device becomes simpler.

Next, the fifth and sixth embodiments will be explained according to FIG.

In this embodiment, as shown in FIG.
It is characterized in that a filter 16 for removing dust is inserted in the middle of the filter. Specifically, when we inserted the filter 16 that removes dust of 0.5 μm or more, we were able to remove a visible amount of dust in the aquarium by using the device only 2 to 5 times (5 to 10 hours). It was confirmed that 100
No visible dust was found even after using the device more than once. That is, water could be easily purified with a simple configuration of inserting a filter into the circulation system of the water channel.

Next, a seventh embodiment will be explained according to FIG. 9.

As shown in the figure, this embodiment is characterized in that a pH control device 30 is provided in a part of the circulation path 12. Specifically, when predetermined amounts of sodium hydroxide solution and salt alcohol were mixed into the device using microsilling, diffusion of sodium hydroxide and salt alcohol, which was difficult in the past, was achieved in this example. Because the water was flowing, it became possible to obtain a predetermined pH within a very short time (5 to 30 minutes). Furthermore, it is clear that according to the present device, it is also possible to control the pH while the monomolecular film is formed on the water surface.

Next, an eighth embodiment will be explained according to FIG. 10.

In this embodiment, as shown in the figure, the circulation path 12
It is characterized in that a heat exchanger 31 is provided in a part of the unit.

Specifically, the diameter is 3/8 inch, the wall thickness is 0, through which the circulating water passes.
．． A heat exchanger 31 is provided in which a 5 mW+ Pyrex glass tube is wrapped around a hollow copper pipe, and a desired temperature is heated inside the copper pipe while being controlled by a temperature control device 32 via a temperature sensor 33 provided in the water tank 3. The temperature of the circulating water was controlled by flowing a liquid at that temperature. As a result, the water in the aquarium,
It was possible to control the temperature within the range of 5 to 80°C with an accuracy of ±0.5°C. Therefore, it has become possible to easily control the temperature conditions during monomolecular film accumulation. Also,
It is clear that according to this apparatus, it is also possible to control the temperature while the middle molecular film is formed on the water surface.

Finally, the ninth embodiment will be described with reference to FIGS. 11(a) and 11(b).

The present embodiment is characterized in that the barrier 8 is configured to be freely movable in the vertical direction in the previous embodiment. Specifically, the barrier 8 is operated by a motor (not shown) (however, manual operation is also possible).
This makes it possible to wash away the unnecessary t11 molecular film 2 on the water surface and turn the water surface into clear grass, which greatly reduces the effort and time required for preparation for monomolecular film accumulation. was completed.

As explained above, the present invention has the effect of facilitating continuous accumulation of a monomolecular film by controlling the surface pressure of the monomolecular film using a liquid flow.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a conventional LB film production apparatus, and Figure 2 is a
A diagram explaining the principle of a method for controlling the surface pressure of a monomolecular film by a water flow, FIG. 3 is a schematic sectional view of the first embodiment of the present invention, and FIG. 4 is a schematic sectional diagram of the second embodiment. 5 is a schematic perspective view of the third embodiment, FIGS. 6(a) and 6(b) are a schematic perspective view and a sectional view of the fourth embodiment, respectively, and FIG. 7 is a schematic perspective view of the fifth embodiment. 8 is a schematic configuration diagram of the sixth embodiment. FIG. 9 is a schematic configuration diagram of the seventh embodiment.
θ diagram is a schematic configuration diagram of the eighth embodiment, FIG. 11(a),
(b) is a schematic sectional view before and after removing the barrier 8 in the ninth embodiment, respectively. 1--1 Monomolecule +a--1 Hydrophilic group 1b-m-Hydrophobic group 2-m-Monolayer 3-m-Water tank 4-Stile 7-m-Water flow generator 8-m-Barrier 9-m-Dripping Region 10-m-cumulative region 11-m-surface pressure forming region 12--1 Circulation path 13-m-water tank ■4--Pump 15--Gate valve 18--Filter 21---pH -en sensor 30---PH control device 31-m-heat exchanger 32-m-temperature control device 33-m-temperature sensor Patent applicant: Canon Co., Ltd. Fig. 7, Fig. 8, Fig. 9

Claims (1)

[Claims] A film formation method characterized in that film formation is performed after controlling the areal density of molecules for film formation by a liquid flow.