JP3407750B2 - Electron beam evaporation equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam vapor deposition apparatus capable of vapor deposition under ultrahigh vacuum.

[0002]

2. Description of the Related Art The pressure during film formation in a conventional vacuum vapor deposition apparatus is about 1 × 10 ^-3 to 1 × 10 ^-4 Pa. This is because the vacuum container was made of glass or stainless steel, and it was impossible or difficult to bake the container necessary to obtain an ultrahigh vacuum. Also, the vacuum pump is a pump whose ultimate vacuum is not so high. Was used,
Furthermore, it was because the vacuum seal was not fully considered.

Under such a pressure, the surface of the substrate is covered with residual gas molecules in only about 1 second. Therefore, the vapor-deposited thin film is insufficient in terms of crystallinity and defects. Further, it is desired to reduce residual gas (impurity gas) also in an apparatus such as an etching apparatus that utilizes gas discharge or gas reaction.

[0004]

As described above, in the conventional vacuum apparatus, the improvement of the degree of vacuum is a major issue, and studies are being conducted in various fields. Therefore, the present invention has been proposed in view of such conventional circumstances, and an object of the present invention is to provide an electron beam vapor deposition apparatus capable of vapor deposition under ultrahigh vacuum and capable of high-quality film formation. And

[0005]

[0006]

In order to achieve the above object, in the electron beam evaporation apparatus of the present invention, the vacuum container is made of aluminum or aluminum alloy, and the inside of the vacuum container is evacuated to an ultrahigh vacuum. The interior of the vacuum vessel comprises a pump and an electron gun for heating the vapor deposition source.
It is processed by spraying fine glass beads together with a high-pressure gas of a mixture of argon and oxygen, and a thin film having a gettering action is placed in the vacuum container, and 1 × 10 ^{−5 is provided.}
It is characterized by being vapor-deposited at a vacuum degree of Pa or less.

[0007]

[0008]

When a vacuum container is made of aluminum or an aluminum alloy and fine glass beads are blown into the inside of the vacuum container together with a high pressure gas of a mixture of argon and oxygen, baking is performed at a relatively low temperature (120 ° C.). An ultrahigh vacuum of 1 × 10 ⁻⁵ Pa or less can be easily obtained by performing the operation for several hours. When vapor deposition by electron beam heating is performed under this pressure, a thin film having good crystallinity and few defects is formed.

Further, when a thin film having a gettering action is formed inside the vacuum container, the thin film adsorbs the residual gas and the released gas in the vacuum container, and the ultimate pressure becomes low, or a clean gas containing less harmful or unnecessary gas is obtained. It becomes a vacuum state.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings.

One Embodiment of Electron Beam Vapor Deposition Apparatus First, an example of an electron beam vapor deposition apparatus to which the present invention is applied will be described. In this electron beam vapor deposition apparatus, as shown in FIG. 1, crucible-integrated electron guns 2 and 3 are installed at the bottom of a vacuum container 1 made of aluminum or an aluminum alloy, and a substrate 4 which is an object to be vapor deposited is placed in the vacuum container. The upper part of 1 can be reciprocally moved.

The vacuum container 1 is made of aluminum or aluminum, copper, silicon, manganese, magnesium,
It is manufactured by welding a plate made of an aluminum alloy in which zinc, chromium, etc. are mixed in about several percent, while keeping the so-called black skin. In this example, an aluminum alloy plate (trade name A6061-T6) having a thickness of about 30 mm was used. After welding, the inside of the vacuum container 1 is subjected to so-called GBB-EX processing.

In GBB-EX processing, fine glass beads are sprayed on a metal surface with a high pressure gas of a mixture of argon and oxygen to remove surface contamination and simultaneously form a uniform and dense oxide film on the metal surface. Is a surface treatment technology for reducing the emission of gas from the surface. By performing such processing, the amount of gas released from the inner wall of the vacuum container 1 can be significantly reduced.

As the surface treatment of the vacuum container 1, the above GB is used.
The B-EX process is most suitable, but in addition to this, an EL process for processing a container using alcohol as a coolant, an EX process for processing a container while cooling by blowing a gas containing argon and oxygen, and the like may be adopted. These techniques can be applied to the vacuum container 1 of the present example because they do not use cutting oil, which is a major obstacle in obtaining a high vacuum, but GBB-E.
Compared to both EL and EX processing methods, X processing has the advantage that processing that is normally required several times can be performed once.

The vacuum container 1 has a gate opening 1a at the top,
1b is provided and configured as a so-called T-shaped chamber. The gate ports 1a and 1b are provided for the purpose of ensuring a span during the reciprocating motion of the substrate 4, maintaining an ultrahigh vacuum environment in the vacuum container 1 and delivering the substrate 4, respectively. An O-ring seal is used so that another vacuum device (for example, a load lock or another film forming device) can be connected via a gate valve.

A door 1c is provided on the front surface of the vacuum container 1, and the door 1c is used to open and close the vacuum container 1. Even in this door 1c, the vacuum container 1 is vacuum-sealed.
-A ring seal is used. The O-ring 5 used in this O-ring seal is made of rubber such as fluorocarbon rubber (so-called Viton), nitrile rubber (NBR), chloroprene rubber, silicone rubber, etc., and fluorocarbon rubber is particularly preferable. Is.

Generally, an ultrahigh vacuum vacuum container made of stainless steel requires baking at a high temperature.
A metal seal is used. On the other hand, in this example, the baking can be performed at a low temperature, so that the above-described rubber O-ring can be adopted, and the opening and closing of the ultra-high vacuum vapor deposition apparatus can be performed very easily.

On the other hand, a flange (not shown) for connecting to the exhaust system is made of an aluminum alloy (trade name: 2).
219-T852) and the gasket is also made of aluminum. The exhaust system is connected via these flanges and gaskets, but in this example, 1 × 10
^-Turbo molecular pump 6 to achieve an ultra vacuum of ^-5 Pa or less
And an exhaust system is constituted by a rotary pump (not shown).

The turbo molecular pump 6 is a magnetic levitation type, made of aluminum, and has a low ultimate pressure and a high hydrogen compression ratio.

Further, the temperature around the vacuum container 1 is about 120.degree.
A sheet-type heater is attached so that baking can be performed. The vacuum container 1 made of aluminum or an aluminum alloy can easily obtain an ultrahigh vacuum by baking at a relatively low temperature for several hours, and is very advantageous in terms of productivity and the like.

As described above, the substrate 4 is a vapor deposition source (hence, a vapor deposition material housed in a crucible integrally formed with the electron guns 2 and 3) in order to improve the film thickness distribution. Reciprocates above. Here, in the shield plate 7 between the substrate 4 and the vapor deposition source (that is, the electron guns 2 and 3),
Slit-shaped openings 8 are provided in order to control the film thickness distribution and the incident direction of the deposit.

In this example, two electron guns 2 and 3 are provided. However, since all of them correspond to an ultra-high vacuum, a rubber O-ring is not used for the connecting portion, and welding or IC is used.
It has an F-flange.

In this way, the electron guns 2, 3 are placed in the vacuum container 1.
Since two units are provided, simultaneous two-source vapor deposition is possible. Further, if a partition plate is provided between these two electron guns 2 and 3, it is also possible to fabricate a so-called artificial lattice film by performing vapor deposition of different materials from the electron guns 2 and 3. . Further, a predetermined film may be formed by one electron gun 2 and a getter film may be formed by the other electron gun 3, and the ultimate pressure may be lowered and the residual gas may be reduced by a getter action described later.

When various vapor deposition films were formed by the electron beam vapor deposition apparatus having the above structure, 1 × 10 ⁻⁵ Pa was obtained.
Under the following ultra-high vacuum, a good thin film having good crystallinity and no defects was obtained. Further, since the electron guns 2 and 3 are used as the heating means of the vapor deposition source, vapor deposition is possible even when the high melting point material is used as the vapor deposition source.

Getter Action by Cr Next, an experiment on the getter action by Cr was conducted. In the experiment, as shown in FIG. 2, a shield plate 9 was provided in the vacuum container 1 so that the inner wall of the container was completely hidden when viewed from the electron guns 2 and 3, and between the two electron guns 2 and 3. Partition board 1
0 was provided to divide the vacuum vessel 1 into two parts. Other configurations are similar to those of the vapor deposition apparatus shown in FIG.

In the vapor deposition apparatus shown in FIG. 2, the vacuum container 1
Since the inner wall of the container is shielded from the electron guns 2 and 3 by the shield plate 9, there is no temperature rise due to radiation from the vapor deposition source, and it is not necessary to cool the container with water. Further, when the getter thin film is vapor-deposited, the getter thin film is generated on the shielding plate 9 and the inner wall of the vacuum container 1 is not contaminated. further,
A huge vacuum pump having an opening area corresponding to the surface area of the shielding plate 9 is formed, and a cleaner vacuum can be obtained.

Using the above vapor deposition apparatus, the getter action of Cr was examined. FIG. 3 shows a pressure change when Cr is vapor-deposited. Initially when the electron beam was incident on the Cr source, the pressure was temporarily 1 × due to degassing from the Cr source.
The pressure rises to about 10 ⁻⁴ Pa, but thereafter the pressure decreases with time, and is kept at about 1 × 10 ⁻⁶ Pa during the vapor deposition of Cr.

On the other hand, FIG. 4 shows a change in pressure after completion of vapor deposition. According to this, it is understood that the ultimate pressure is the lowest about one day after the completion of the vapor deposition. A pressure that is about an order of magnitude lower than the base pressure is obtained, which is the pumping speed (60
It shows that an exhaust speed (6000 liters / second) 10 times that of 0 liters / second) is obtained. After that, the exhaust capacity of the getter thin film gradually declines, and the pressure slowly returns to the base pressure.

From the above, the following can be understood. First,
Cr has a good getter action, and the ultimate pressure is reduced. As is clear from FIG. 4, such a function is exhibited even when the getter film is formed before the work (for example, film formation or etching), and as shown in FIG. Alternatively, it is exhibited even when the getter film is formed intermittently.

The getter action means the action of adsorbing gas molecules, and in addition to Cr, Ti, Al, Zr, N
This ability is high in metals such as b, Ta, Mo, W, V, Ca, Ba, and Mg. In particular, it has a high evacuation capacity under ultrahigh vacuum pressure.

FIG. 5 shows changes in pressure when Al is vapor-deposited by one electron gun and Cr is vapor-deposited by another electron gun. A current of 50 to 60 mA is applied to the Cr electron gun. It is understood that the pressure is decreased by about one digit when Cr is given (when the getter action is exhibited when Cr is vapor-deposited as shown in FIG. 3). Emission current is 2 for Al.
After vapor deposition at 40 mA, the current value described in the figure is the emission current value of Cr at that time.

As described above, the getter film can be formed immediately before or at the same time as forming a predetermined film by providing the evaporation source for depositing a thin film having a getter action in the evaporation apparatus. Therefore, the ultimate pressure can be lowered by the getter action described above, and a clean vacuum with less residual gas and released gas can be obtained. Further, by separating the area where the getter film is formed and the area where the predetermined film is formed by the partition plate 10, the getter film can be formed without contaminating the predetermined film.

In order to prevent a thin film having a getter action from being formed directly on the inner wall of the vacuum container 1, a replaceable getter film forming plate may be separately provided in the vacuum container 1. Further, although the vacuum vapor deposition apparatus is used in this example, it may be applied to an etching apparatus that performs etching under ultrahigh vacuum, or may be applied to a sputtering apparatus. When applied to a sputtering device, a target and a cathode for forming a predetermined thin film on a substrate as well as a target and a cathode for forming a getter film may be provided. The pressure can be reduced to remove the residual gas, and high quality film formation can be achieved.

Example of MBE Device FIG. 6 shows an example of an MBE device. Also in this MBE device, the vacuum container 21 is made of aluminum or an aluminum alloy.

In the MBE device, a Knudsen cell 22 which is a heating device for evaporating a predetermined substance is installed at the bottom of the vacuum container 21, and the evaporate evaporated from the Knudsen cell 22 enters. The area is limited.

Therefore, a getter film forming portion is provided on the inner wall of the vacuum container 21 so that the getter film is formed in a region including a place other than where the substrate 23 is set in the vacuum container 21. Alternatively, a getter film generation plate is provided. In this example, a replaceable plate placed along the inner wall of the vacuum container 21 is used as a getter film generation unit, and a getter film generation plate 24 is provided on the back side of the opening 21a of the vacuum container 21 in which the substrate 23 is arranged. Is installed.

Unlike the ordinary Knudsen cell, an evaporation source 25 (for example, an electron gun evaporation source or an induction heating evaporation source) capable of performing evaporation at a relatively wide angle is provided in the vacuum container 21 as a getter thin film. It is provided as a vapor deposition source. This makes it possible to form the getter film immediately before forming a predetermined film.

At this time, the substrate 23 is placed at a position where a getter film is not formed, and is placed in the opening 21a only when a predetermined film is formed. Further, if the getter film is arranged so as not to enter the substrate 23 from the beginning, the getter film can be formed while forming a predetermined film.

The specific embodiments to which the present invention is applied have been described above, but the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Needless to say.

[0040]

As is clear from the above description, according to the electron beam vapor deposition apparatus of the present invention, a high quality film can be vapor deposited under ultrahigh vacuum. Further, since electron beam heating is adopted as the heating means, it is possible to cope with a vapor deposition material having a high melting point.

According to the electron beam vapor deposition apparatus of the present invention, the vacuum container is made of aluminum or aluminum alloy, and fine glass beads are blown into the inside of the vacuum container together with a high pressure gas of a mixture of argon and oxygen. When applied, an ultrahigh vacuum of 1 × 10 ⁻⁵ Pa or less can be easily obtained by baking at a relatively low temperature (about 120 ° C.) for several hours.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an example of an electron beam evaporation apparatus to which the present invention is applied.

FIG. 2 is a schematic view showing an example of a vapor deposition device provided with a shield plate and a partition plate.

FIG. 3 is a characteristic diagram showing a pressure change when Cr is vapor-deposited.

FIG. 4 is a characteristic diagram showing a pressure change after completion of deposition of Cr.

FIG. 5 is a characteristic diagram showing a pressure change due to Cr vapor deposition when depositing Al.

FIG. 6 is a schematic diagram showing an example of an MBE device to which the present invention is applied.

[Explanation of symbols]

1,21 ... Vacuum container 2, 3 ... Electron gun 4, 23 ... Substrate 5 ... O-ring 6 ... Turbo molecular pump 9 ... Shield plate 10 ... Partition board 24: Getter film generation plate 25 ... Evaporation source (evaporation source for getter film formation)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masanobu Yamamoto 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Within Sony Corporation (72) Inventor Katsumi Takahashi 1-6-1, Takezono, Tsukuba, Ibaraki (In Japanese) No. 50-37352 (JP, A) JP 61-24214 (JP, A) JP 63-291421 (JP, A) JP 62- 142762 (JP, A) JP-A-3-279469 (JP, A) JP-A-51-99648 (JP, A) JP-A-4-99268 (JP, A) JP-A-4-99271 (JP, A) Actual Kaihei 3-14144 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 14/00-14/58 B01J 3/00

Claims (7)

(57) [Claims] 1. A vacuum container is formed of aluminum or an aluminum alloy, and has a vacuum pump for evacuating the inside of the vacuum container to an ultrahigh vacuum and an electron gun for heating a vapor deposition source, and the inside of the vacuum container is Is processed by spraying fine glass beads together with a high-pressure gas of a mixture of argon and oxygen, and a thin film having a getter action is placed in the vacuum container, and vapor deposition is performed at a vacuum degree of 1 × 10 ⁻⁵ Pa or less. An electron beam vapor deposition apparatus characterized by the above. 2. The electron beam vapor deposition apparatus according to claim 1, further comprising film forming means for forming a thin film having a getter action in the vacuum container. 3. The electron beam vapor deposition apparatus according to claim 1, wherein the opening / closing portion of the vacuum container is sealed by a rubber O-ring. 4. The electron beam vapor deposition apparatus according to claim 1, further comprising a getter film deposition plate on which a thin film having a getter action is deposited in a vacuum container. 5. The electron beam vapor deposition apparatus according to claim 1, wherein at least a part of a region where a thin film having a getter action is formed is separated from a region where a predetermined thin film is formed. 6. The electron beam vapor deposition apparatus according to claim 1, further comprising an evaporation source for forming a thin film having a getter action and an evaporation source for forming a predetermined thin film. 7. The electron beam vapor deposition apparatus according to claim 1, further comprising a target and a cathode for forming a thin film having a getter action and a target and a cathode for forming a predetermined thin film.