JPH02104660A - Laser-beam sputtering method - Google Patents

Abstract

PURPOSE:To form a good-quality film at a high rate by irradiating a target jointly with long wave and shortwave laser beams, sputtering the component molecule, and depositing the molecule on a substrate. CONSTITUTION:A laser beam 1 is introduced into a vacuum chamber 13 through a lens 10 and an inlet window 12b, and the target 2 is irradiated with the focus. Consequently, the target 2 is sputtered, and the component molecule 3 sputtered from the surface is deposited on the substrate 4 opposed to the target 2 to form a film. In the laser-beam sputtering method, a long wave laser beam such as a YAG laser beam and a shortwave laser beam such as an excimer laser beam are jointly used. The film forming rate is increased by the heat energy of the long wave laser beam. Meanwhile, the vaporized molecule is ionized and energized by the shortwave laser beam, and the crystallinity, uniformity, and adhesion of the deposited film are improved. Since the long-wave and shortwave laser beams are jointly used, the film forming rate is increased, and the quality of the deposited film can be improved.

Description

Detailed Description of the Invention (Industrial Application Field) The laser beam sputtering method of the present invention relates to an improvement in the method of beam sputtering a film of a compound or alloy consisting of two or more components. It is used to obtain membranes.

(Prior art) Conventionally, PVD sputtering, vacuum evaporation, ion plating, MBE (molecular beam epitaxial), etc. have been used as film forming methods. According to these methods, high quality films can be created. However, the PVD method has the disadvantage that the film forming speed is slow.Among the conventional film forming methods, a laser sputtering method is a high speed film forming method.

(Problems to be Solved by the Invention) The conventional laser sputtering method has the following problems.

(2) Although it is a high-speed film forming method, the film forming speed is not very fast if a short wavelength laser is used.

■ If you use a long wavelength laser, you can achieve a large average power.
Although the film forming speed is improved because it can be used for multiple applications, the film quality (crystallinity, uniformity, adhesion to the substrate, surface morphology, etc.) deteriorates.

(2) In the case of multi-component substances, large compositional deviations occur.

■The elements ejected from the tube may reach the substrate before the reaction is complete, making it difficult to form a high-quality film, and in some cases, the same element may reach the substrate. It had to be heat treated afterwards. However, doing so would complicate the process and hinder industrialization.

■ To solve the problem of @note■, it is possible to increase the energy of the particles flying out from the target, but if the beam output is increased for this purpose, the film forming rate changes and a one-composition shift occurs. Because of this, it is not possible to impart significant energy to the particles.

■ It was difficult to obtain a film with good crystallinity because the particle energy could not be increased.

■ In multi-component films, even if you try to increase the film formation rate, the reaction cannot keep up.

(Object of the Invention) The object of the present invention is to form a film using a combination of a short wavelength laser beam and a long wavelength laser beam, thereby achieving a high film forming speed and a high quality film using laser beam sputtering. It is about providing law.

Another object of the present invention is to apply a short wavelength laser beam to the vicinity of the substrate on which the film is deposited at the same time as the laser beam sputtering! The object of the present invention is to provide a laser beam sputtering method that promotes photochemical reactions and facilitates the deposition of constituent molecules onto a substrate by irradiating the eyebrows, thereby making it possible to obtain a high-performance, high-quality film.

Means for Solving Problem C) The laser beam sputtering method according to claim 1 of the present invention comprises:
As shown in Figures 1 to 4, the laser beam l is directed to the target 2.
The composition molecules 3 of the target 2 are scattered, and the same composition molecules 3 are placed on the substrate 4 placed opposite the target 2.
The laser beam sputtering method for depositing is characterized by the combined use of a long wavelength laser beam 5 and a short wavelength laser beam 6 as shown in FIG. 2 as laser beams.

The laser beam sputtering method according to claim 2 of the present invention includes:
A first aspect of the laser beam sputtering method is characterized in that the target 2 is irradiated with a long wavelength laser beam 5 and a short wavelength laser beam 6 at the same time as shown in FIG.

The laser beam sputtering method according to claim 3 of the present invention includes:
As shown in FIGS. 1 and 2, the target 2 is irradiated with both or one of the long wavelength laser beam 5 and the short wavelength laser beam 6 to scatter the constituent molecules 3 of the target 2, and the target 2 is faced to the target 2. In the Gezabeam scattering method, molecules 3 of the same composition are deposited on the substrate 4 placed at It is characterized by irradiating a beam 20.

1 to 4 are explanatory diagrams of the laser beam sputtering methods according to the first to third aspects of the invention.

In these figures, 2 is the target, 4 is the substrate,
These are placed in the vacuum chamber 13 facing each other.

The target 2 is disk-shaped, and its center is fixed to a rotating shaft so that it can be rotated at any speed. Further, the target 2 is designed so that its vertical position can be adjusted by a stepping motor according to its wear and tear.

The substrate 4 is attached to a fixture 17, and the fixture 17 can be rotated up and down by vertical movement. Further, the substrate 4 is heated to a predetermined temperature according to the necessary film forming conditions, and the film deposited on the substrate 4 is heat-treated by the heat.

The vacuum chamber 13 is formed with a gas inlet 15° and laser beam introduction windows 12a and 12b.
, 12b, a beam stopper 16 is installed on the opposite side. In addition, a lens 10 is provided in front of the introduction windows 12a and 12b.
．． 11 are arranged.

This vacuum chamber 13 is evacuated by, for example, a turbo molecular pump, and the degree of vacuum can be adjusted as necessary during vapor deposition to a level of high vacuum to 1 torr. Particularly in the case of oxide vapor deposition, 02
Film formation is often carried out by introducing gas and adjusting the gas pressure from 10-' to t torr.

The laser beam introduction windows 12a, 12b, the lens 10.
The material No. 11 is selected according to the wavelength of the laser used. For example, Z is used when λ=10.6 μm for a CO2 laser.

Using S, material, 1=0 with K rF z excimer laser
．． When the thickness is 248 μm, synthetic quartz or M or F is used.

In the present invention, the long wavelength laser beam 5 (Figs. 1 and 2) irradiated to the target 2 is a Y laser beam with a wavelength of 1 μm or more.
AG laser (λ=1.06um) and CO2 laser (e=1.06um)
10.6 μm) is suitable. Furthermore, as the short wavelength laser beam 6 (Fig. 2) in the same invention, an excimer laser (λ
= 157 nm to 351 nm), H, -Ca laser, A,
"Lasers are suitable, especially excimer lasers with a wavelength of 0.5 μm or less (K, F, A, F, etc.), A, 'lasers, H,
-C, laser is effective.

The long wavelength laser beam 5 and the short wavelength laser beam 6 are
Considering the uniformity of the obtained film, surface 1 of target 2
It is desirable to condense the light into a flat (rectangular) shape on 4. In the case of an excimer laser, the beam shape is rectangular, so it can be used as is.

In the case of YAG lasers, CO lasers, a cylinder lens is used to focus the beam into a rectangular shape.

A short wavelength laser beam 20 (FIG. 4) in the third aspect of the invention is generated from a laser source 21 shown in the same figure. This laser source 21 is an F excimer laser (wavelength: 248 nm).
m), an output of 30W is suitable. This short wavelength laser beam 2
0 is introduced into the vacuum chamber 13 from the beam introduction window 13 through the lens 12 in FIG.

Although the short wavelength laser beam 6 in FIG. 2 and the short wavelength laser beam 20 in FIG. 4 are generated from separate light sources, both laser beams 6 and 20 may be generated from the same light source. is divided into two beams by a branch.

Figure 3 shows the target 2 and substrate 4 in Figures 1 and 2.
A plasma excitation mechanism including an RF power source 18 and an RF coil 19 is provided between the two.

This plasma excitation mechanism is for ionizing and accelerating the constituent molecules 3 scattered from the target 2 to improve the quality of the film obtained on the substrate 4.

(Function) In the invention of claim 1, since the long wavelength laser 5 and the short wavelength laser 6 are used together as shown in FIG. 2, the film forming speed is high due to the interaction of both wavelengths, and a high quality film can be obtained. .

In the second invention, as shown in FIG.
Since the surface 14 of the target 2 is irradiated with the short wavelength laser 6 and the short wavelength laser 6, the energy of these laser beams is absorbed by the surface 14 of the target 2, and the constituent molecules 3 of the target 2 are evaporated by thermal or photochemical action. , the same molecules 3 are deposited on the substrate 4. In this case, the long wavelength laser beam 5
Since the target 2 is irradiated with the laser beam 6 and the short wavelength laser beam 6 at the same time, the composition molecules 3 deposited on the substrate 4 tend to become atomic or molecular due mainly to the thermal energy of the long wavelength laser beam 5, and the average power of the laser beam The film forming speed increases in proportion to this.

Since the short wavelength laser beam has energy to ionize vapor molecules, some of the vaporized constituent molecules are ionized and become particles with a certain amount of energy and are deposited on the substrate 4, improving crystallinity, uniformity, and adhesion. will improve.

When the compositional molecules 3 of the target 2 are multi-component substances, a deviation in the composition ratio is likely to occur because the melting points of the compositional components are different, but in the second invention, not only the long wavelength beam 5 but also the short wavelength laser beam 6 is used in combination. Therefore, deviations in the composition ratio due to the photochemical effect of the short wavelength laser beam 6 are less likely to occur.

Further, the constituent molecules 3 of the target 2 are often deposited on the substrate 4 in the form of clusters (clumps of atoms or molecular groups),
A layer with good crystallinity, uniformity, and adhesion is deposited, but when only a short wavelength laser is used, the average power is smaller than that of a long wavelength laser, so there is a limit to the film forming speed. Since the laser beams 5 are irradiated at the same time Q=t, the film forming speed becomes faster.

In the laser beam sputtering method according to the third aspect of the invention, the second
As shown in the figure, irradiate the target 2 with both or one of the long wavelength laser beam 5 and the short wavelength laser beam 6, and target! Since the composition molecules 3 of ~2 are scattered, when the target 2 is irradiated with the long wavelength laser beam 5, the target 2 tends to become atomic or molecular due mainly to the thermal energy of the same long wavelength laser beam 5, and the uniform power of the laser beam The film forming speed increases proportionally. Historically, as shown in FIG. 4, before the composition molecules 3 reach the substrate 4, a short wavelength laser beam 7 is applied to the composition molecules 3.
is irradiated, a photochemical effect and an ionization effect are applied to the molecules of the same composition: 3, the reaction is promoted, a part of them is ionized, and the particles are deposited on the substrate 4 as particles having a certain amount of energy.

(Example 1) As an example of the first and second inventions, FIGS.
A +200W CO8 laser is used as the long wavelength laser beam 5 in the figure, and a wavelength of 248 W is used as the short wavelength laser beam 6.
nm, using an F excimer laser (average power 35 W, repetition 20 [lz]), using Y, B, C, 307 (7) sintered target as substrate 4. Film formation was performed using M, 0 (100). Is the same substrate 4 during film formation? The temperature was set at 400°C.

The above-mentioned C02 laser and excimer laser were each connected to a Z laser with a focal length of M+5 inches. Using a Syu lens and a synthetic quartz lens, a vacuum chamber 1 is constructed as shown in FIG.
A horizontal beam was fired onto the surface 14 of the target 2 in the target 3. At this time, 02 gas was introduced into the empty chamber 13, and the gas pressure inside the chamber was adjusted to 80 m torr during the vapor deposition. In this way, even at a high film forming rate of 600 persons/sec, a film (Y, B
, , ,C,.

908) was obtained. The critical temperature Tc of this film was approximately 60°C, but by annealing it in oxygen, Tc
When c=78, a characteristic of critical current Jc=6×10'A/cm'' was obtained.

For comparison with this Example 1, when only a C02 laser (long wavelength laser) was used, Y was significantly depleted and the obtained film did not exhibit superconducting properties.

Furthermore, when only an excimer laser (short wavelength laser) was used, the film forming rate was reduced to about 10 people/min.

(Embodiment 2) FIG. 3 is another embodiment of the first and second inventions,
This film was formed under almost the same conditions as in Example 1, except that a voltage was applied from the RF power source 18 to the RF coil 19 between the target 2 and the substrate 4 to create a plasma state between the substrate 4 and the target 2. This is what I did.

In this case, a denser film than in Example 1 was obtained.

The composition ratio of the film is Y + B aaICu3. oOm
Met. After annealing in oxygen, the film has Tc=8
7, the characteristic of jc=5XlOSA/cm2 was obtained.

(Embodiment 3) FIG. 4 is an embodiment of the invention according to claim 3. As the beam source 7 of the laser beam I in FIG.
As another beam source 21, an F excimer laser (wavelength 248 nm) is used.
Using an output of 30 W, beam scattering was performed while irradiating the front side of the substrate 4 with the short wavelength laser beam 20 from this beam source 21. In this case, the short wavelength laser beam 2
0 is a focal length of 0 inches, Z, S, is introduced into the vacuum chamber using a lens 1 directly below the substrate 4.
It was converged at 0 cm. Directly below the substrate 4 is a wide, diverging light. At this time, material 1 as target 2,
B, , C, were combined in a volume ratio of 1:1:3 as shown in FIG. 5 to form a disk shape of 50φ.

Further, MgO was used for the substrate 4, and the same substrate 4 was heated to 500°C. Glue with a film thickness of 1 um in about 1 minute, B.
A crystallized oxide thin film with a molar ratio of , C, approximately l:2:3 was obtained.8 For comparison with this Example 3, the short wavelength laser beam l from the laser source 7 was not irradiated. An oxide thin film was prepared under the same conditions as in the previous example, and its composition ratio was analyzed. The molar ratio of B9, B1, and Cm was 1:4:9. The critical temperature Tc and critical flow rate Je of this oxide thin film were measured. The results are shown in Table 1.

(Margin below) Table 1 Next, the target materials in Example 3 were changed to SF and T, and beam scattering was performed in the same manner as in Example 3 under the same conditions as in Example 3. Here, the volume ratio of SF and T was approximately 1:1. In this way, oxide thin films were created five times, and each of the obtained oxide thin films was chemically analyzed. The results are shown in Table 2.

In addition, in order to compare with this Example 3, oxide thin films were created five times under the same conditions as Experimental Example 3 without irradiation with the short wavelength laser beam 20, and chemical analysis of each of the obtained oxide thin films was performed. I did it. The results are also shown in Table 2.

Table 2 (Example 4) As an example of the third invention, as in Example 1,
In Figure 2, a 1200W CO2 laser is used as the long wavelength laser beam 5, and a wavelength of 248 nm is used as the short wavelength laser beam 6.
However, using an F excimer laser (average power 35W, repetition 20H2), Y IB − is used as target 2.
Film formation was performed using a sintered target of TC-SOY and M, 0 (100) as the substrate 4. During film formation, the temperature of the substrate 4 was kept at 400°C.

And the focal length of each of the above-mentioned CO ole laser and excimer laser! Using a 115-inch Z, S, lens and a synthetic quartz lens, vacuum chamber 1 was constructed as shown in FIG.
The surface 14 of the target 2 in the target 3 was horizontally irradiated. At this time, O gas was introduced into the empty chamber 13 instead of the 02 gas in Example 1. Further, as shown in FIG. 4, the composition molecules 3 near the substrate 4 were irradiated with a short wavelength laser beam 20.

The composition of the pus obtained is Y:Ba:Cu=1=2
:It was close to 3. But Tc is 84 and Jc is 7
7 and 10'A/cm''.

(Effects of the Invention) The laser sputtering methods according to claims 1 and 2 of the present invention use both the thermal energy of light from the long wavelength laser beam 5 and the photochemical reaction energy from the short wavelength laser beam 6, so that the following effects can be achieved. There is an effect.

(2) The film forming rate is as fast as 10 to 1,000 people/sec, which is much higher than conventional sputtering and vacuum evaporation methods.

(2) The film quality, such as crystallinity and adhesion, is significantly improved compared to the conventional laser sputtering method, which uses either the long or short wavelength.

(2) Since the target 2 is irradiated with the laser beams 5.6 of both long and short wavelengths at the same time, deterioration such as unevenness and compositional deviation on the surface of the target 2 is also suppressed.

In the laser beam sputtering method according to the third aspect of the present invention, the composition molecules 3 evaporated from the target 2 are irradiated with the short wavelength laser beam 20 in front of the substrate 4, so that the following effects can be obtained.

As is clear from Table 1, a thin film with excellent critical temperature T and critical flow rate Jc can be obtained.

As is clear from Table 2, in the conventional method, the composition deviation is significant and the deterioration is rapid, but in the present invention, a film having a desired composition can be stably obtained.

01 Table 19 From Table 2, in the present invention, short wavelength laser beam 7 is applied near the substrate! ■The effect of radiation is obvious,
It becomes possible to obtain high-quality films at high speed. This has a great effect in promoting the practical application of oxide superconductors.

■ In addition to short wavelength laser beam 6, short wavelength laser beam 2
0 is used, thereby promoting crystallinity and adhesion, which are significantly improved compared to the case without laser beam 7.

Furthermore, if an RF coil 18 is installed between the substrate 4 and the target 2 to increase the ion effect of sputtered molecules, the film quality can be further improved.

[Brief explanation of the drawing]

Fig. 1 is a side explanatory view showing an example of the laser sputtering method of the present invention, Fig. 2 is a plan explanatory view of the same method, Fig. 3 is a side explanatory view of the other side of the same method, and Fig. 4 is a further different laser sputtering method. FIG. 5, a side explanatory view of the beam sputtering method, is a schematic diagram of a target used in the same sputtering method. l is the laser beam 2 is the target 3 is the composition of the target molecules 4 is the substrate 5 is the long wavelength laser 6. 20 is the short wavelength laser

Claims (3)

[Claims] (1) Laser beam sputtering method in which a laser beam 1 is irradiated onto a target 2 to scatter the compositional molecules 3 of the target 2, and the same compositional molecules 3 are deposited on a substrate 4 placed opposite the target 2. A laser beam sputtering method characterized in that a long wavelength laser beam 5 and a short wavelength laser beam 6 are used together as laser beams. (2) In the laser beam sputtering method of claim 1,
A laser beam sputtering method characterized by simultaneously irradiating a target 2 with a long wavelength laser beam 5 and a short wavelength laser beam 6. (3) The target 2 is irradiated with both or one of the long-wavelength laser beam 5 and the short-wavelength laser beam 6 to scatter the constituent molecules 3 of the target 2, and the molecules 3 of the target 2 are scattered onto the substrate 4 placed opposite the target 2. A laser beam sputtering method for depositing compositional molecules 3, characterized in that the compositional molecules 3 flying onto the substrate 4 near the substrate 4 are irradiated with a short wavelength laser beam 20.