JPH0533125A - Laser vapor-deposition device - Google Patents

Abstract

PURPOSE:To remove the vaporized particle deposited on the incident window for laser beam of the vacuum vessel of a laser vapor-deposition device. CONSTITUTION:An opening 3 for making a laser beam incident on the flank of a vacuum vessel 2 is provided and a transparent window member 4 made of an insulator is hermetically loaded on the opening 3. Electrodes 7 and 8 are supported by an insulating holder 11 and abutted on the window member 4 by springs 12 and 13. Rods 9 and 10 fixed to the electrodes 7 and 8 are connected to a power source 14 through a switching means 15. When the vaporized particles (m) are deposited in the window member 4, the switching means 15 is closed to impress a voltage between the electrodes 7 and 8, hence a current passes through the deposited particles (m), and heat is produced. The particles (m) deposited on the window member 4 are vaporized by the heat and removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser vapor deposition apparatus for vaporizing an evaporation substance in a vacuum by a laser beam to form a vapor deposition film on a substrate such as a silicon wafer.

[0002]

2. Description of the Related Art A laser vapor deposition apparatus irradiates a vacuum container provided with an optically transparent entrance window for entering a laser beam and a laser beam from outside the vacuum container to an evaporation material in the vacuum container through the entrance window. And a laser light source that operates. With this configuration, the evaporation material and the base material that is the object to be processed are placed in a vacuum container, and the evaporation material is evaporated by irradiating the evaporation material under vacuum with a laser beam through the entrance window and adheres to the surface of the base material. Then, a vapor deposition film is formed. Since the laser vapor deposition apparatus can increase the degree of vacuum as compared with the conventional vapor deposition apparatus, it is possible to form a dense vapor deposition film having a small amount of impurities and a high degree of adhesion to a substrate.

In the conventional laser vapor deposition apparatus, since the inside of the entrance window is contaminated by the deposition of vaporized particles and the laser beam is blocked, stable and continuous vapor deposition cannot be performed. Therefore, when performing the vapor deposition process for a long time, the vapor deposition is stopped midway and the window member is replaced, and the vacuum inside the vacuum container must be evacuated each time, so there is a problem of poor efficiency.

Therefore, various proposals have been made to solve these problems, for example, JP-A-62-7745.
In Japanese Patent Laid-Open Publication No. 6-242, an exhaust box having minute holes for passing a laser beam is provided in a vacuum container so as to cover its entrance window, and an inert gas is supplied into the exhaust box. A device is disclosed. With this configuration, the inert gas is supplied to make the pressure in the exhaust box higher than that of the vaporized substance side in the vacuum container, and the inert gas is blown from the minute holes to the vaporized substance side to fly toward the incident window. Contamination of the entrance window is prevented by blowing off evaporated particles.

Further, Japanese Patent Application Laid-Open No. 63-11660 discloses a laser vapor deposition apparatus in which a rotary shutter is provided so as to reduce contamination of an entrance window of a vacuum container, and Japanese Patent Application Laid-Open No. 63-157861. Discloses a laser deposition apparatus capable of monitoring a contamination state of an entrance window of a vacuum container.

[0006]

However, in the one disclosed in Japanese Patent Laid-Open No. 62-77456, it is impossible to blow off all the vaporized particles flying toward the entrance window, and therefore the fine particles pass through the minute holes. The evaporated particles are gradually attached to the entrance window. Therefore, the contamination of the entrance window cannot be completely prevented. Further, since the degree of vacuum in the vacuum container is lowered by the inert gas, there are problems that the adhesion of the vaporized particles to the substrate is lowered, and the vapor deposition film is likely to become a horus and the film quality is deteriorated.

In Japanese Patent Laid-Open No. 63-11660,
It is not possible to completely prevent contamination of the entrance window during continuous oscillation. Further, in Japanese Patent Laid-Open No. 63-157861, it is impossible to prevent the evaporation particles from adhering to the entrance window.

The present invention has been made in view of the above points, and an object of the present invention is to provide a laser vapor deposition apparatus capable of completely removing the vaporized substance adhering to the entrance window of the vacuum container.

[0009]

In order to solve the above-mentioned problems, the laser vapor deposition apparatus of the present invention includes a window member made of an insulator capable of transmitting a laser beam in a laser beam incident window provided in a vacuum container. It is characterized in that it is mounted, an electrode is attached to the window member, and the electrode is connected to a power source through a switching means.

[0010]

With this structure, when a voltage is applied to the electrode with the vaporized particles attached to the window member, a current flows through the vaporized particles attached to the window member to generate heat, and this heat causes the window member to be heated. Evaporated particles attached to are evaporated and removed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a vertical cross section of a window portion, which is a main part of the laser vapor deposition apparatus of this embodiment, and FIG. 2 shows the entire apparatus.

As shown in FIG. 2, in the laser vapor deposition apparatus 1 of this embodiment, the side wall of the vacuum container 2 is provided with an opening 3 for laser light incidence.
Is provided, and a transparent window member 4 made of an insulator is airtightly attached to the opening 3. In the vacuum container 2, the evaporation material container 5 for containing the evaporation material M and the evaporation material container 5
A base material holder 6 for holding a base material W, which is an object to be processed, is provided above the base material. In addition, the vacuum container 2 has a vacuum device (not shown) for evacuating the vacuum container 2.
Are connected. A laser light source (not shown) that irradiates the evaporation material M with laser light through the opening 3 is provided outside the vacuum container 2.

As shown in FIG. 1, inside the window member 4 attached to the opening 3, an electrode 7 and an electrode 8 which are in contact with the window member 4 are provided at a distance from each other. The electrodes 7 and 8 are rods connected to the back side thereof, respectively.
9, 10 are slidably inserted in an insulating holder 11 fixed to the side wall of the vacuum container 2, and springs 12, 13 interposed between the electrodes 7, 8 and the insulating holder 11 cause the window member 4 to move. Pressed. The rods 9 and 10 are connected via a switching means 15 to a power supply 14 that applies a voltage to the electrodes 7 and 8. In the figure, 16 is a seal member interposed between the vacuum container 2 and the window member 4.

The operation of this embodiment having the above-mentioned structure will be described below. First, the evaporation material M is placed in the evaporation material container 5.
Then, the base material W is attached to the base material holder 6, and the inside of the vacuum container 2 is evacuated by a vacuum device. Next, the evaporation material M is irradiated with laser light through the window member 4. The evaporation material M is evaporated by the laser light, and the evaporated particles adhere to the surface of the base material W to form a vapor deposition film.

On the other hand, the evaporated particles also adhere to the inner wall of the vacuum container 2 and the inside of the window member 4. When the switching means 15 is closed and a voltage is applied between the electrode 7 and the electrode 8 with the evaporated particles attached to the window member 4, a current flows through the evaporated particles attached to the window member 4 to generate heat. Due to this heat, the evaporation particles attached to the window member 4 are evaporated and removed. In addition,
The evaporation particles attached to the window member 4 can be removed in parallel with the vapor deposition process of the substrate W.

Next, the relationship between the voltage E [v] for removing the evaporated particles adhering to the window member 4 and the application time t [s] will be described. Now, as shown in FIG. 3, assuming that a film m of evaporated particles having a width w and a thickness x [cm] is attached between the electrodes 7 and 8, the distance d [cm] between the electrodes 7 and 8 is assumed. ], And the specific resistance μ [μΩcm] of the deposited film m, the resistance R [Ω] between the electrodes 7 and 8 is R = μd / wx. Therefore, the film m of the vaporized particles due to the applied voltage E
The heat generation amount Q [J] of is: Q = (E ² / R) t = (wxE ² / μd) t On the other hand, the heat quantity Q ₁ [J] required to evaporate the film m of the vaporized particles having a volume V [cm ³ ] is equal to the film m of the vaporized particles.
Density ρ [g / cm ³ ], specific heat C [J / g], melting point T _m
[K], heat of sublimation q [J / g], and T at room temperature T ₀ [K]
= T _m −T ₀ , Q ₁ = Vρ (CT + q) = wxdρ (CT + q). Assuming that the film m of evaporated particles is adiabatic, Q ₁
= Q, (wxE ² / μd) · t = wxdρ (CT + q). Therefore, E ² = μρ (CT + q) d ² / t.

Here, taking the case where the evaporation material M is iron as an example, ρ = 7.87 [g / cm ³ ] and μ = 100 [μΩ
cm], C = 0.80 [J / g], T = 1500 [K],
Since q = 6.53 × 10 ⁻³ [J / g], E ² = 0.94 × d ² / t. Therefore, the distance d between the electrodes 7 and 8 is d = 1.
If [cm], the voltage E [v] of the power supply 14 and the application time t
The relationship with [s] is E ² = 0.94 / t. Here, if the application time t is t = 1 [s],
The voltage E of the power supply 14 is E = 0.97 [v]. The heat generation amount Q at this time is as small as Q = 0.003 [J] if w = 3 [cm] and x = 1 × 10 ⁻⁷ [cm], and this heat generation causes the electrodes 7, 8 and The window member 4 is not damaged.

When the evaporation material M is iron, nickel or cobalt, the applied voltage is E = 10 to 50 [v] and the applied time is t = 0.001 to 1 [s], and the window member 4 is actually used.
FIG. 4 shows the state of stains and damages on the window member 4 when the evaporated particles attached to the are removed.

As described above, the window member 4 can be kept in a clean state by intermittently applying a voltage to the electrodes 7 and 8. Further, the damage of the window member becomes smaller as the applied voltage E is increased and the application time t is shortened.

Although the window member is described as transparent in the above-mentioned embodiments, it may be optically transparent at the wavelength of the laser beam and can be used in this kind of field, for example, CO the ₂ laser KCl, ZnSe, MgF _2, and synthetic quartz and the like is an excimer laser. Further, the window member does not need to be an insulator as a whole, and may be formed of an insulator only on the surface to which the vaporized particles adhere. The electrode attached to the window member does not need to be provided in the vacuum container,
Although an appropriate sealing means is required, the window member may be provided so as to penetrate from the outside of the vacuum container. The voltage applied to the electrodes may be an intermittent method or a continuous method that is applied when the amount of vaporized particles attached to the window member reaches a certain amount.

[0021]

As described above in detail, in the laser vapor deposition apparatus of the present invention, the electrodes are attached to the window member of the vacuum container, and the voltage is applied between the electrodes. Are evaporated and removed. As a result, the window member is in a clean state, and stable and continuous vapor deposition can be performed. Further, since it is possible to remove the vaporized particles attached to the window member in parallel with the vapor deposition process, it is possible to perform the vapor deposition process for a long time without stopping the vapor deposition on the way, which is excellent in that the vapor deposition process efficiency is improved. Produce an effect.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of an embodiment of the present invention.

FIG. 2 is a schematic diagram of the entire laser vapor deposition apparatus according to an embodiment of the present invention.

FIG. 3 is an explanatory view showing a film of evaporated particles and electrodes attached to a window member of the apparatus of FIG.

FIG. 4 is a table showing applied voltages, application times, and conditions of window members in the laser deposition apparatus of FIG.

[Explanation of symbols]

 1 Laser Vapor Deposition Device 2 Vacuum Container 3 Opening 4 Window Member 7,8 Electrode 14 Power Supply 15 Switching Means M Evaporated Material W Base Material

Claims (1)

Claim: What is claimed is: 1. A window member made of an insulator capable of transmitting laser light is attached to a laser light incident window provided in a vacuum container,
An electrode is attached to the window member, and the electrode is connected to a power source via a switching means.