JPS59140366A - Method and device for producing thin film - Google Patents

Abstract

PURPOSE:To form a thin film of the resulting product of thermal decomposition having high quality without changing the structural function of a base body by ejecting gaseous flow of a reactive gaseous material to a substrate while irradiating a laser beam thereto and moving at the same time the substrate two- dimensionally. CONSTITUTION:A laser beam projector 3 is fixed above a sample base 2 provided with a two-dimensional driving mechanism 1, and a laser beam is made incident perpendicularly to the center A of the substrate 4 on the base 2. A reactive gaseous material is projected as fine and high velocity gaseous flow from pencil nozzles 5, 5 toward the incident point A. The base 2 is manipulated two-dimensionally in this state to form film surface and thin film pattern. All the points on the substrate 4 are heated instantaneously only on the extremely thin surface layer when they pass the irradiating point of the laser beam according to the movement in X-, Y directions and are quickly cooled after the passage thereof. The stage for manufacturing the thin film is thus executed at a lower temp. and the thin film having high quality and adhesion strength is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for producing a thin film, and more particularly, the present invention relates to a thin film manufacturing method and an apparatus thereof, and more particularly, to irradiating and heating a substrate with a laser beam, and at the same time injecting a high-speed airflow of a reactive gaseous substance onto the substrate. The present invention relates to a method and an apparatus for forming a thin film of a thermal decomposition product of a reactive gaseous substance on a substrate by moving the gas two-dimensionally.

Conventionally, when manufacturing a thin film on the surface of a substrate by chemical reaction, the substrate is heated or the entire reaction chamber containing the substrate is heated to thermally decompose the reactive gas around the substrate and generate thermal decomposition products. A thin film was formed on the substrate.

However, in such conventional thin film forming methods, since the entire space around the substrate is at high temperature, the thermal decomposition products of the reactive gas may be further thermally decomposed secondary or tertiary, or the thermal decomposition products may be thermally decomposed. There is a problem in that pits of various sizes occur in the thin film formed by the reaction of substances with undecomposed reactive gases.

In addition, since the substrate is heated strongly, it may cause distortion, warping, elongation, shrinkage, etc. of the substrate, loss of dimensional accuracy due to heating, deterioration of the structure of the substrate itself, and changes in the functional structure already formed on the substrate. However, there was a drawback that a lot of damage occurred to both the formed thin film and the substrate.

Further, the same drawbacks as described above cannot be avoided even when forming thin films by physical methods under vacuum such as vacuum evaporation, sputtering, and ion plating.

Therefore, the present invention was made to eliminate such conventional drawbacks, and it is possible to instantaneously heat only the surface of the substrate irradiated with the laser beam, inducing a thermal decomposition reaction limited only to the heated surface. In addition, the specific wave energy of the laser beam itself can chemically decompose the reactive gas existing on the substrate surface and the space adjacent to it without any thermal process. It has features such as enabling surface reaction, producing a high-quality thin film, and not changing the functional structure of the substrate.

That is, in the thin film manufacturing method of the present invention, while heating the substrate by irradiating the substrate with a laser beam, a flow of a reactive gaseous material is injected onto the substrate, and at the same time, the substrate is moved two-dimensionally to form the substrate. This method is characterized in that a thin film of thermal decomposition products of the reactive gaseous substance is formed on the surface of the substrate.

Further, the thin film manufacturing apparatus of the present invention is comprised of a substrate, a laser beam projector and a reactive gaseous material injection nozzle that are respectively provided at intervals on the substrate, and is capable of driving the substrate two-dimensionally. It is characterized by:

Since the present invention is a method for moving a substrate two-dimensionally, it is also generally referred to as a substrate driving method.

What is important in such a substrate driving method is to irradiate a laser beam with a wavelength (λL) that matches the intrinsic absorption wavelength (λI+) of the substrate. Normally, the laser beam is reflected, transmitted, and absorbed by the substrate, but the laser beam is absorbed by the substrate only when λ and λ match.

The larger the absorption coefficient (α) of the substrate, the more the laser beam that penetrates into the substrate is absorbed closer to the substrate surface, usually within 10 μm, and converted into heating energy, resulting in instantaneous surface layer heating. , the surface of the substrate is usually heated to 5008C to 600C.

In the present invention, by moving the substrate two-dimensionally, the substrate is swept by a laser beam, and as the substrate moves, the substrate surface is sequentially and instantaneously heated, and a reactive gas is generated on the substrate surface. A thin film of pyrolysis products forms.

The figure is a schematic diagram showing an embodiment of the thin film manufacturing apparatus of the present invention, in which a laser beam projector 6 is vertically positioned at a height of at least 10α above a sample stage 2 equipped with a two-dimensional (X, Y) drive mechanism 1. , and the laser beam is made perpendicularly incident on the center A of the substrate 4 on the sample stage 2. Pencil nozzles 5, 5 are arranged toward this incident point A, and the reactive gaseous material is injected into the system as a thin high-speed air stream.

In this state, the sample stage 2 is operated two-dimensionally to form a film surface or a thin film pattern. The laser beam can be narrowed down to a minimum of several micrometers by the lens system of the projector B, and therefore it is also possible to draw a precise line diagram with a line width of several tens of micrometers. The pencil nozzle 5 has a radius of 5 around the laser beam incident point A.
Arrange the required number within 5 heights on the hemisphere within Crn.

As all points on the substrate move in the X or Y direction, when they pass the laser beam irradiation point, for example point A, they are instantaneously heated to a high temperature, and only a very thin surface layer is heated.
After passing through, it is quickly cooled down.

That is, only the very surface layer of the substrate is heated to a high temperature by the laser beam irradiation to the point where it causes a chemical change. The thickness of the surface heating layer is approximately 10
It is within μm.

The reactive gas existing in the space in contact with the irradiation point A on the substrate is instantaneously thermally decomposed, and a thin film of thermal decomposition products is deposited at the beam irradiation point A on the moving substrate. This A
The thickness of the overlying film material varies with the speed of movement of the substrate; as the speed of movement increases, the rate of film material deposition decreases.

Therefore, in order to maintain a constant thickness of the deposited film, the energy of the beam must be increased as the moving speed of the substrate 4 increases.

By the way, according to the study results of the inventors, the beam energy E (watts) and the substrate moving speed u (crn/5e
It was found that there is the following relationship between e).

E: u415 That is, it is understood that in order to form a uniform film surface over the entire substrate surface, it is necessary to keep the substrate moving speed constant at a given laser beam energy.

In the present invention, a monolayer film or a multilayer film structure can be formed by using various reactive gaseous substances together through the reactive gaseous substance injection nozzles 5, 5.

The sample stage 2 is driven by an air cylinder or an electric motor, and its maximum driving length is 5oCrn or more. This substrate driving method is extremely superior in precision microfabrication.

As the substrate used in the present invention, all substrates used in conventional thin film forming methods can be used.
Examples include glass plates, metal plates, quartz plates, and ceramic plates.

In addition to these substrates, plastic, wood, etc. can also be used.

The diameter of the beam generated by a normal laser oscillator is small;
Since the diameter is less than 10rn0mφ, the formed film surface also has circular spots of the same size. Therefore, in order to form a thin film on a wide surface, the beam diameter must be expanded to the required size. However, increasing the beam diameter reduces the energy density at the irradiated surface, making it difficult to induce thermal decomposition reactions.

Furthermore, since there is an energy distribution in the cross section of the beam, the film thickness becomes non-uniform.

Therefore, in the present invention, a laser beam having a finite diameter is used and the substrate is moved two-dimensionally to promote spot deposition successively, ultimately resulting in the rapid formation of a wide film surface.

In the present invention, the reactive gaseous substance refers to a gaseous substance that is thermally decomposed very quickly when it comes into contact with the heated substrate surface, that is, a gaseous or fume-like thermally decomposable raw material. A clean thin film of decomposition products forms.

The laser used may be continuous wave or pulse wave as long as it has an output of several 1.0 mW or more.

Preferably, the laser beam has a large heat-generating effect when irradiated onto the substrate, in other words, the substrate efficiently absorbs the laser beam.

Therefore, an optimal combination exists between the substrate and the laser beam.

For example, for Si substrates, Ar laser (wavelength 04
For ceramics and glass, YAG laser (106 μm), HF/DF chemical laser (2,5-4,06 μm), CO2 laser
(106 μm) is used. The greatest advantage of the present invention is its versatility in that, like conventional high temperature chemical vapor deposition methods, any reactive chemical can be used as a reactive gaseous source.

Therefore, the thin film materials that can be manufactured are extremely wide-ranging. For example, AA, Si, Cr, Ni, Cd, F
e, etc., MoSi2. WSi2. TaSi2.
PtSi, , NbSi2゜NiCr, 5n
Cu, ZnCu, InSb, GaSb
, LaGa, NdNi.

Alloys such as Nb5AA + NbSn and B1Te, and compound materials such as Sin, +At203. Ti
e2. ZrO2,5n02 +In2O3,Fe2O3
oxides such as SiC, TiC, B, C.

WC, VC; Carbide such as ZrC, TiN, B
N, AtN, TaN.

Si3N4. Nitride such as CrN, VN, 'ril
l, , ZrB2°CrB2. WB, La
B6. Covers almost all surfaces and functional membranes for electronic, information, energy, machinery, and chemical industries, including borides such as MoB, and other sulfides.

As described above, the present invention provides obvious effects that are not available in the prior art.

In other words, only the very surface layer of the substrate is heated to a high temperature until a chemical change is caused by the sweeping irradiation of the laser beam due to the two-dimensional movement of the substrate. The thickness of the surface heating layer is approximately within 10 μm. Therefore, the humidity of the substrate itself does not increase, high temperature reactions occur only in the surface layer, and the substrate is cooled in a short time. In effect, the thin film manufacturing process has been lowered in temperature.

Therefore, unlike the conventional thin film manufacturing method in which the entire substrate or the entire substrate and surrounding raw material gaseous material is heated, there are almost no secondary or tertiary decomposition reactions or side reactions, and the objective is achieved. It is possible to preferentially perform only those thin film forming reactions that The produced film is of high quality and has excellent adhesion strength, which is characteristic of films produced by high-temperature reactions.

Furthermore, when producing an oxide film according to the present invention, there is the advantage that it can be carried out in the atmosphere. Moreover, it is also possible to continuously manufacture large-area membrane surfaces.

When the reactive thin plate gas flow is stabilized or a special gas atmosphere or reduced pressure/vacuum is required, the reaction can be carried out in a closed room or a bell jar.

Note that the laser beam is introduced into the sealed chamber through a window provided in the wall of the chamber. A crystal material with high transmittance to the laser beam is used as the window material. Crystal plates that can be used regardless of whether the wavelength of the laser beam is in the infrared region or the visible region include Zn5e, MgF2. LiF, CaF
2. BaF2. NaC1, KCI.

Examples include KBr. Especially, 5in2. LiF
.

MgF2 etc. show good performance in the visible range.

Examples of the present invention will be described below.

Ni and W film surfaces and patterns were formed using a substrate driving method. As shown in the figure, there are two holes in the center of the cylindrical bell jar 6.
The dimension (X, Y) I drive sample stage 2 was fixed, and the beam projector 6 was vertically attached above the drive center of the sample stage 2. The dimensions of the bell jar 6 were 300+nmφ×450 m, and a beam entrance window 6A with a Zn5e plate (diameter 30 mm apart) was provided in the center of the ceiling. Test #2 is 80 stones x 80 square meters in size.
The height including the two-dimensional (x, y) drive mechanism 1 is approximately 150m.
It is m. The beam projector 3 is located 1'50 directly above the sample stage 2.
Installed directly below the beam entrance window 6A at a height of rMl,
A sharp focus A is focused on the sample stage 2'' by the S1 short focus lens, and from this focus position A, a pencil nozzle 5 is placed on a hemispherical surface of approximately 2 ctn, aiming at the beam focus A. did. Pencil nozzle 5 is made of stainless steel, dimensions are 6mmφ x 80mm, nozzle bottom diameter is 06mmφ
It is.

A polished alumina substrate (50 mm x 50 +
n+n
After creating an Ar atmosphere of Torr, two nozzles 5.5
The vapors of N1(Co) and WF6 are alternately added to H2.
Injected with gas. At the same time, while continuously irradiating the CO2 laser beam L, operate the sample stage drive mechanism 1 to
A raster pattern consisting of i and W vapor deposition lines was formed. The energy of the incident CO2 beam is 8 watts, N
The temperature of 1(Co) is 150℃, and the temperature of WF is 1
The amount of gas injected at 0°C5 is approximately] l/mm.

The moving speed of the sample stage was 2 mm/see.

The number of strands of the manufactured raster pattern was 10, the line pitch was 3 mm, the line width was 100 to 150 μm, and the height was about 0.5 μm. The cross section of the wire is chevron-shaped, approximately 200~
The hem widens by about 500 μm. Furthermore, when both the beam energy and the sample stage driving speed were increased by three times, the spread of this tail was reduced to less than 1/2.

The surface of the deposited Ni film had a silver color, and the surface of the W film had a black-gray color.

[Brief explanation of the drawing]

The figure is a schematic diagram showing an embodiment of the thin film manufacturing apparatus of the present invention. 1. Two-dimensional drive mechanism 6. Laser beam projector 4
...Substrate 5...Reactive gaseous substance injection nozzle. Patent applicant: Director of the Agency of Industrial Science and Technology Kawa 1) Hirobe Designated Agent: Ryozo Hayami, Director of the Osaka Institute of Industrial Science and Technology, Agency of Industrial Science and Technology

Claims (1)

[Claims] 1. While irradiating and heating the substrate with a laser beam, a flow of a reactive gas is injected onto the substrate, and at the same time, the substrate is moved two-dimensionally to improve the surface of the substrate. A method for producing a thin film, comprising forming a thin film of a thermal decomposition product of the reactive gaseous substance. 2. Consisting of a substrate, a 1/-the beam projector and a reactive gaseous substance injection nozzle spaced apart from each other on the substrate,
A thin film manufacturing apparatus characterized in that the substrate can be driven two-dimensionally.