JPS61271060A - Formation of film - Google Patents

Abstract

PURPOSE:To deposit smoothly a monomolecular film on a substrate and to prevent the adverse effect of vibration by positioning the substrate above the water surface on which a group of film forming molecules is developed and moving the water surface up and down with respect to the substrate. CONSTITUTION:When a monomolecular film or its built-up film is formed on a substrate in the fields of semiconductor techniques, optical techniques, etc., a desired amt. of water is stored in a shallow and wide water vessel 1, a substrate 7 is held by a substrate holder 8 almost in parallel with the water surface 3 and with the surface to which the monomolecular film is to be transferred directed downward, an air bag 13 is provided under water and the amt. of air in the bag 13 is increased and decreased. At first, air is not let in, a monomolecular film forming substance is added dropwise while keeping the substrage 7 out of contact with the water surface 3, then air is sent in from the regulation part 14, the water surface 3 is raised and brought into contact with the substrate 7 and a monomolecular film is transferred. Since the liq. surface is thus moved up and down and the monomolecular film is transferred, the film is deposited smoothly and finely.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for forming an organic thin film that is a main component of a device, for example in the semiconductor technology field and the optical technology field. The present invention relates to a film forming method for forming a monomolecular film or a cumulative film thereof on a substrate by forming a monomolecular layer on a liquid surface and transferring the monomolecular layer to a substrate.

[Prior 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.

However, recent technological advances in the field of organic chemistry have been remarkable, and logic elements,
Integrated circuit devices such as memory elements and photoelectric conversion elements,
Proposals have been made to construct part or all of the functional parts (mainly thin film parts) of optical devices such as microlens arrays and guiding waveguides with organic thin films instead of conventional inorganic thin films.

Organic giW is a key component of such devices.
X is produced using a single molecule accumulation method. Single molecule accumulation method (
The Langmuir-Prodgett method (also known as the LB method) is a method that utilizes the woody properties and hydrophobicity of molecules with woody groups and hydrophobic groups to form a monomolecular film by spreading them on water in an orderly manner. By transferring this onto the substrate surface, it is possible to form a monomolecular film or a monomolecular cumulative film (these are referred to as LB films) on the substrate.

Conventionally, this type of apparatus has a frame 2 hung inside a shallow and wide rectangular water tank 1 so as to horizontally partition a water surface 3, as shown in FIG. The frame 2 functions as a two-dimensional cylinder, and a rectangular float 4 is floated inside the frame 2, and the width of the float 4 is made slightly narrower than the inner dimension of the frame 2, so that it can move smoothly from side to side as a two-dimensional piston. It is possible to move. In order to move the float 4 from side to side, the float 4 is connected to a winding device 6 using a motor or the like via a wire 5.

When forming a monomolecular film, the constituent substances of the film are dissolved in a volatile solvent such as benzene or chloroform, and the solution is dropped onto the water surface 3. After the solvent evaporates, a monomolecular film exhibiting the behavior of a two-dimensional system is left on the water surface 3. When the areal density of molecules is low,
It is called a gas film of secondary gas. By moving the float 4 to the right, the expanse of the water surface 3 on which single molecules expand is reduced and the surface density is increased. As a result, interactions between molecules become stronger, and two-dimensional liquids pass through a liquid film of two-dimensional liquid. Transforms into a solid film. When this solid film is formed, the molecules are arranged and oriented in a neat manner, resulting in a high degree of order and uniform ultra-thin film properties required for materials constituting semiconductors and the like.

As a method of transferring the monomolecular film from the water surface 3 onto the substrate 7 surface, the substrate 7 is attached to the substrate holder 8 while maintaining a constant surface pressure suitable for accumulation operation on the monomolecular film on the water surface 3.
There is a vertical dipping method in which a monomolecular film is transferred by moving the monolayer up and down in the vertical direction 9. In this method, as shown in FIG. 3(a), the monomolecular film 10 is attached only during immersion, and
There are three types: Y type, in which the monomolecular film 10 adheres both during dipping and pulling up, as shown in ), and X type, in which the monomolecular film 10 adheres only during pulling, as shown in FIG. 3(C). In addition, the second
In the molecule shown in the figure, 11 is a hydrophilic portion and 12 is a hydrophobic portion.

In addition to this, another method (not shown) is a horizontal adhesion method in which the monomolecular film is transferred by moving the substrate up and down with the monomolecular film attachment surface of the substrate approximately parallel to the water surface. .

[Problems to be Solved by the Invention] In the conventional method described above, a geared motor or the like is used as a device to move the substrate up and down, and the vibrations generated by this motor are transmitted to the substrate, causing monomolecular When the film is attached to the substrate, there is a problem in that the state of attachment is disturbed.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a film forming method in which a monomolecular film can be smoothly attached to a substrate without the adverse effects of vibration.

[Means for solving the problem] The means for achieving the L-product objective is to position the substrate above the water surface where the film-forming molecule group is developed, and to form a film by moving the water surface up and down with respect to the substrate. It's a method.

As methods for raising and lowering the water level, there are two methods: raising and lowering the water level within the tank, and raising and lowering the tank itself containing water.

[Function] According to the present invention, the transfer of the film-forming molecules is carried out by raising and lowering the water surface rather than the substrate, so the substrate can remain fixed at a fixed position, and The negative effects of mechanical vibration can be prevented.

By the way, it is expected that some turbulence will occur on the water surface when it is raised and lowered, but even if the water surface becomes slightly porous, the vibrations of this turbulence will not be transmitted to the fixed substrate, so mechanical vibrations will not be applied. When a substrate is immersed under water, the vibration of the substrate simultaneously disturbs the water surface, and the orientation of the obtained monomolecular film or its cumulative film is determined by both the vibration of the substrate and the disturbance of the water surface. Sexual harm is prevented.

The film forming principle itself in the method of the present invention is the same as the LB method described in the conventional example.

[Examples] Hereinafter, the present invention will be described in detail with reference to Examples and the drawings.

FIG. 1 is a longitudinal sectional view showing an example of a film forming apparatus using a horizontal deposition method in which the present invention is implemented. In FIG. 1, the film forming apparatus stores a desired amount of water inside a shallow and wide water tank l,
The substrate 7 is held by the substrate holder 8 with the surface on which the monomolecular film is to be transferred facing downward, almost in a straight line on the water surface 3, and an air bag 13 is provided in the water, and air is used to increase or decrease the amount of air in the air bag 13. It is roughly constructed by connecting 3J adjustment parts 14.

FIG. 1(a) shows a state in which air is not sufficiently supplied to the air bag 13, the water surface 3 is at a low position, and the substrate 7 is not in contact with the water surface 3. In this state, a monomolecular film constituent material is dropped onto the water surface 3 and a monomolecular film having a desired surface pressure is formed using a surface pressure control means (not shown). Here, when air is sent into the air bag 13 from the air volume adjustment unit 14, the water level 3 rises by the amount of volume increase, so that a monomolecular film is formed on the lower surface of the substrate 7, as shown in FIG. 1(b). come into contact with it and be transferred to it. In this case, the rise of the water surface 3 is very smooth and there is no vibration as in the conventional case, so the transferred film is also precise. Furthermore, since a mechanism for moving the substrate up and down is not required, the apparatus becomes extremely simple and the substrate can be easily held, making it possible to utilize the advantages of the horizontal deposition method for forming films on large-sized substrates.

In addition, in the embodiment described in L, the explanation was given using the X-type film formation in which the water surface 3 is raised, but the substrate 7 is submerged in water in advance and the water surface 3 is raised.
It is also possible to form a Y-type film that lowers the temperature.

A similar effect can also be obtained by placing a liquid bag underwater that uses liquid instead of air.

FIG. 4 is a longitudinal cross-sectional view showing another example of a film forming apparatus using a water-moisture deposition method according to the present invention. In FIG. 4, the film forming apparatus stores a desired amount of water in a shallow and wide water tank 1, and holds a substrate 7 in a substrate holder with the surface to which the monomolecular film is to be transferred facing downward, approximately parallel to the water surface 3. 8, a liquid flow port 15 is provided in the water, and a liquid amount adjusting section 16 connected to the liquid flow port 15 is attached to the water tank l. The liquid discharged and sucked into the water tank l from this liquid flow port 15 is selected to have a specific gravity sufficiently higher than that of water so as not to float to the water surface 3, and a relatively high viscosity so as not to cause wave motion. Liquid flow port 15 is also located near the bottom of the water. Of course, water itself may be used as the liquid, and in that case, the above consideration is not required.

FIG. 4(a) shows a state in which no liquid is released into the water, the water surface 3 is at a low position, and the substrate 7 is not in contact with the water surface 3. In this state, the monomolecular film constituent material is applied to the water surface 3. A monomolecular film having a desired surface pressure is formed using a surface pressure control means (not shown). Here, when the liquid is slowly fed into the water from the liquid flow port 15, the water level 3 rises by 1 by an amount corresponding to the amount of liquid, so as shown in FIG. come into contact with each other and are transferred. In this case, the advantages such as the precision of the film and the simplicity of the device are the same, and in addition to forming an X-shaped film that raises the water level 3, the substrate 7 is submerged in water and the water level 3 is lowered. Similarly, Y-type film formation is also possible.

FIG. 5 is a longitudinal sectional view showing still another example of a film forming apparatus using a horizontal deposition method according to the present invention. In Fig. 5, the film forming apparatus is arranged such that a frame 2 horizontally partitions a water surface 3 inside a shallow and wide water tank 1, and the surface to which the monomolecular film is to be transferred faces downward, almost parallel to the water surface 3. The substrate 7 is held by a substrate holder 8, and a water tank vertical movement mechanism 17 is provided for vertically moving the water tank l.

FIG. 5(a) shows a state in which the water tank l is in the upper direction,
In this state where the substrate 7 is not in contact with the water surface 3, a monomolecular film constituent material is dropped onto the water surface 3, and a monomolecular film having a desired surface pressure is formed by a surface pressure control means (not shown). Here, when the water tank 1 is raised by the water tank vertical movement mechanism 17, the water surface 3 naturally rises, and as shown in FIG. 5(b), the monomolecular film comes into contact with the lower surface of the substrate 7 and is transferred. in this case,
If the water level 3 rises slowly and smoothly, there is no need to consider the vibration of the substrate as in the conventional method, and the transferred film is also precise. Furthermore, unlike the vertical movement mechanism for the substrate, the apparatus is extremely simple and the substrate can be easily held, so the advantages of the horizontal deposition method for forming films on large-sized substrates can be utilized.

In the above embodiment, the X-shaped film formation was explained in which the water surface 3 was raised, but the substrate 7 was submerged in water in advance and the water surface 3 was raised.
It is also possible to form a Y-type film that lowers the temperature.

[Effects of the Invention] As explained above, according to the present invention, the liquid level is moved up and down to transfer the monomolecular film on the liquid surface to the bottom surface of the substrate, so there is no vibration of the substrate and the monomolecular film is It adheres smoothly and is precise, and there is no vertical movement mechanism for the substrate, which simplifies the equipment and makes it easy to hold the substrate, so it is possible to deposit a film on a large substrate, making it suitable for the water deposition method. A method for forming a film can be provided.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of one embodiment of the present invention, FIG. 2 is a perspective view of a conventional example, FIG. 3 is a structural diagram of molecular orientation of a monomolecular film or a cumulative film, and FIGS. 4 and 5 are FIG. 7 is a longitudinal cross-sectional view of another embodiment of the invention. 1...Aquarium, 2...Frame (partition), 3...Water surface, 4
... Float, 5... Wire, 6... Winding device, 7
... Substrate, 8 ... Substrate holder, 10 ... Monomolecular film, 13 ... Air bag, 14 ... Air amount adjustment section. 15...Liquid flow port, 16...Liquid amount adjustment section, 17
...Aquarium vertical movement mechanism.

Claims (1)

[Claims] A film forming method characterized by positioning a substrate above a water surface on which a group of molecules for film formation have been developed, and raising and lowering the water surface relative to the substrate.