JP3025834B2 - Ion beam sputter deposition equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, optical thin films,
Alternatively, the present invention relates to an ion beam sputter deposition apparatus used for producing a thin film for a semiconductor.

[0002]

2. Description of the Related Art FIG. 3 shows the configuration of a conventional ion beam sputter deposition apparatus. A target 2 made of a substance to be formed into a film is placed in a vacuum chamber 1, and a deposition target 3 is placed facing the target 2. The object 3 is, for example, a semiconductor substrate or an optical element. The vacuum chamber 1 is made of a conductor and is usually maintained at a ground potential. Further, the internal air is exhausted from the exhaust port 9 and is maintained in a vacuum state. An ionization chamber 6 is mounted on the side wall of the vacuum chamber 1. The ionization chamber 6 is formed of a cylindrical metal case, and is separated from the electric potential of the vacuum chamber 1 by an insulator 12 and mounted. The end face of the metal case constituting the ionization chamber 6 facing the target 2 is opened and covered with a coarse mesh to form an ion outlet 6A. The other end is closed, and a gas supply pipe 8 is attached to the closed surface to supply, for example, argon gas into the ionization chamber 6.

In the ionization chamber 6, an anode 10 and a hot cathode 7 are arranged to face each other. A positive voltage EPO of, for example, about 1 KV is applied to the anode 10 from the power supply 11 as an acceleration voltage.
The hot cathode 7 has a positive voltage EB of several tens to several hundreds of volts.
To cause a discharge between the hot cathode 7 and the anode 10 to generate argon gas plasma. The gas is ionized by the generation of the plasma. Almost the potential of the anode 10 is applied to the ions. A metal case constituting the ionization chamber 6 has a voltage E located between the anode 10 and the hot cathode 7.
C is supplied from the power supply 11. The target 2 is arranged so as to face the ion outlet 6A. Since the same ground potential as the vacuum chamber 1 is applied to the target 2, a potential difference of about 1 KV is applied between the inside of the ionization chamber 6 and the target 2 by connecting the terminal 11 </ b> A of the power supply 11 to the ground. The ion beam 4 is accelerated by the potential difference and collides with the target 2.

[0004] When the ion beam 4 collides with the target 2, atoms 5 are beaten from the target 2, and the atoms 5 adhere to the surface of the object 3 to form a thin film.

[0005]

SUMMARY OF THE INVENTION Acceleration of ion beam 4
Voltage strikes atom 5 from target 2 most efficiently
Because it is set around 1KV that meets the conditions for
The ion beam 4 deviating from the target 2 strikes the inner wall of the vacuum chamber 1.
When it collides, it also strikes atoms from the inner wall of vacuum chamber 1
No matter when these atoms are mixed into the thin film as impurities
The inconveniences that occur also occur.

[0006] In the conventional ion beam sputtering method, the true
The degree of vacuum in the empty tank 1 is about 10 ^-2 to 10 ^-3 Pa (Pascal).
Can be lowered at any time. However, ionization chamber 6
Argon gas leaks out of the thin film.
However, there is an inconvenience that a case may occur in which

[0007] Since the ions in the ion beam 4 fly with the same potential applied thereto, a repulsive force is generated between the ions, and the ion beam 4 tends to spread during the flight. For this reason, the rate at which ions are deviated from the target 2 and collide with the inner wall of the vacuum chamber 1 increases. An object of the present invention is to reduce the rate at which argon gas leaks into the vacuum chamber, further increase the rate at which ions collide with the target, and if the ions come off the target,
An object of the present invention is to provide an ion beam sputter deposition apparatus that can prevent an impurity from being knocked out from the inner wall of the vacuum chamber even if it collides with the inner wall of the vacuum chamber, and thus can generate a thin film having good film quality. is there.

[0008]

According to the present invention, the ionization chamber is disposed outside the vacuum chamber, and a positive high voltage is applied to the ionization chamber and the target while a ground potential is applied to the vacuum chamber.
This high voltage is several tens of meters higher than before between the ionization chamber and the vacuum chamber.
It is applied as an acceleration voltage that is 0 times higher. Therefore, ions are accelerated with a high voltage from the ionization chamber until entering the vacuum chamber, but an acceleration voltage of, for example, about 1 KV is applied between the target and the ionization chamber, which can efficiently strike atoms as in the past. I do.

According to the present invention, since a positive high voltage is applied to the ionization chamber and the target and a ground voltage is applied to the vacuum chamber, a large acceleration voltage is applied between the ionization chamber and the vacuum chamber. As a result, the ion beam jumping out of the ionization chamber flies while maintaining a focused state by a high acceleration voltage,
The probability of hitting the target can be increased. Further, since the ionization chamber is arranged outside the vacuum chamber, an exhaust port can be provided between the ionization chamber and the vacuum chamber. By exhausting from the exhaust port, argon gas leaking from the ionization chamber can be exhausted. As a result, there is no possibility that the argon gas leaking from the ionization chamber enters the vacuum chamber, and the environment around the deposition target 3 can be kept clean.

Further, even if the ion beam comes off the target and collides with the inner wall of the vacuum chamber, a high potential difference is applied between the target and the vacuum chamber. Therefore, the ion beam deviating from the target is accelerated again and collides with the inner wall of the vacuum chamber. The ions accelerated by the high potential difference are knocked into the inner wall of the vacuum chamber, and do not knock out impurities from the inner wall of the vacuum chamber.

Therefore, there is obtained an advantage that a high-quality thin film free of impurities is produced due to the combination of these conditions.

[0012]

FIG. 1 shows the configuration of an ion beam sputter deposition apparatus according to the present invention. Parts corresponding to those in FIG. 3 are denoted by the same reference numerals. In the present invention, a target 2 disposed inside the vacuum chamber 1 is electrically separated from the vacuum chamber 1 by an insulator 13, and a hole 1A is formed in a wall surface of the vacuum chamber 1, and the same axis as the hole 1A is formed. A cylindrical projecting tube 16 is mounted on the outer wall surface of the vacuum chamber 1 so as to project therefrom. The protruding tube 16 is electrically connected to the same electric potential as the vacuum chamber 1, that is, the ground potential.

The ionization chamber 6 is insulated and supported by the insulator 12 on the tip side of the protruding tube 16. Power supply 1
1A is disconnected from the ground, and the ground and the terminal 11A are disconnected.
And an acceleration voltage source 15 is connected. This accelerating voltage source 1
5 is also applied to the target 2 supported inside the vacuum chamber 1. The voltage EVO of the acceleration voltage source 15 is selected to be a high positive voltage, for example, about 50 KV.

An exhaust port 14 is provided in the projecting pipe 16 at a position between the ionization chamber 6 and the vacuum chamber 1, and exhaust is performed from the exhaust port 14. That is, it is connected to an exhaust device such as a vacuum pump.

[0015]

According to the above construction, the ions generated in the ionization chamber 6 have the ground potential on the wall of the vacuum chamber 1 and the potential of the ions generated in the ionization chamber 6 is applied to the anode 10. Is done. Since the voltage becomes substantially equal to VP = EVO + EPO, if EVO = 50 KV and EPO = 1 KV, the potential difference between the ionization chamber 6 and the hole 1A formed in the vacuum chamber 1 becomes 51 KV. The state of this potential is shown in FIG.

L ₁ shown in FIG. 2 is the length in the ionization chamber 6,
L ₂ indicates the distance between the ionization chamber 6 and the target, and L ₃ indicates the length of the target 2 in the flight direction of the ion beam 4. The ions generated inside the ionization chamber 6 are first accelerated by this potential difference VP = 51 KV, and start flying as the ion beam 4 toward the vacuum chamber 1. The ion beam 4 passing through the position of the hole 1A continues to fly toward the target 2, but since the target 2 is supplied with the voltage EVO from the acceleration voltage source 15,
In this state, the acceleration voltage is only the voltage EPO applied to the anode 10. By setting EPO to EPO ≒ 1KV,
When the ion beam 4 arriving inside the vacuum chamber 1 collides with the target 2, the ion beam 4 is decelerated to the speed at which it strikes the atoms 5 most efficiently.

Since the ion beam 4 emitted from the ionization chamber 6 is accelerated at an acceleration voltage several tens of times higher than the conventional acceleration voltage, in this example, 50 times, the convergence of the ion beam is maintained and the beam proceeds straight without spreading. I do. Therefore, the probability of colliding with the target 2 can be increased. Moreover, even if the target 2 is deviated from the target 2, the ions that have deviated from the target 2 are accelerated again by the voltage EVO of the accelerating voltage source 15 applied between the target 2 and the vacuum chamber 1. Will collide with the inner wall. The ions accelerated by the high voltage are knocked into the collision surface and do not strike atoms from the inner wall of the vacuum chamber 1. Therefore, even if ions deviating from the target 2 are present, no impurities are knocked out from the inner wall of the vacuum chamber 1.

Further, according to the present invention, since the exhaust port 14 is provided in the middle of the protruding tube 16 and the exhaust port 14 is also exhausted, even if the argon gas leaks out of the ionization chamber 6, the argon gas is exhausted. It is possible to prevent the gas from being exhausted from the port 14 and entering the vacuum chamber 1. Therefore, it is possible to prevent the gas component from adhering to the object 3 to be deposited, and it is possible to obtain a practical advantage that a good quality thin film can be manufactured by overlapping these conditions.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a potential distribution diagram for explaining the operation of the present invention.

FIG. 3 is a cross-sectional view for explaining a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum tank 2 Target 3 Deposition object 4 Ion beam 5 Atom 6 Ionization chamber 7 Hot cathode 8 Gas supply port 9,14 Exhaust port 10 Anode 11 Power supply 12,13 Insulator 15 Acceleration voltage source 16 Projection tube

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 G02B 1/10 G02B 5/28 H01J 37/301 H01L 21/203

Claims (2)

(57) [Claims] 1. A. First Embodiment B. a vacuum chamber maintained at the ground potential and the inside of which is suctioned to a vacuum state; B. a protruding tube that communicates with a hole formed in the wall of the vacuum chamber and protrudes from the outer wall surface of the vacuum chamber; B. an ionization chamber which is insulated and supported by the protruding end of the protruding tube, and has an anode and a hot cathode disposed inside thereof; A gas supply port for supplying gas to the ionization chamber; B. a power source for applying a discharge electric field between the anode and the hot cathode provided in the ionization chamber to ionize the gas supplied from the gas supply port; So as to increase the voltage between this power supply and ground potential
B. an accelerating voltage source inserted to superimpose an accelerating electric field on a discharge electric field applied between the anode and the hot cathode; The acceleration voltage source supported insulated in the vacuum chamber
Given voltage is provided with a target to emit atoms as a film forming material by irradiation of the ion beam emitted from the ionization chamber, H. The voltage of the ionization power supply given to the anode and the
The sum of the voltage of the accelerating voltage source and the voltage given to the target
The voltage of the accelerating voltage source
An acceleration electric field superimposed on the electric field is formed, and the acceleration electric field
After receiving the accelerated ion beam irradiation, the target
From the film forming material, and given to the anode
Between the voltage of the ionization power source and the voltage of the acceleration voltage source.
The difference between the sum voltage and the ground potential given in the vacuum chamber
As a result, a high accelerating electric field superimposed on the discharge electric field is formed.
Of the ion beam accelerated by the high accelerating electric field
Radiation from the inner wall of the vacuum chamber so that no electrons are emitted.
The voltage of the ionization power supply and the acceleration voltage source is selected
Ion beam sputter deposition apparatus characterized in that
Place. 2. The protruding pipe according to claim 1, wherein
An exhaust port is provided for exhausting gas in the outlet pipe
An ion beam sputter deposition apparatus characterized by the above-mentioned.