CN109427526B

CN109427526B - Ion beam irradiation apparatus

Info

Publication number: CN109427526B
Application number: CN201810532390.5A
Authority: CN
Inventors: 土肥正二郎; 小野田正敏; 高桥元喜
Original assignee: Nisshin Ion Machine Co ltd
Current assignee: Nisshin Ion Machine Co ltd
Priority date: 2017-08-31
Filing date: 2018-05-29
Publication date: 2020-07-31
Anticipated expiration: 2038-05-29
Also published as: JP6414763B1; JP2019046627A; CN109427526A

Abstract

The invention provides an ion beam irradiation device capable of simplifying maintenance operation of a beam current measuring instrument. The ion beam irradiation apparatus (1) has a beam current measuring instrument (P) fixed at an ion beam irradiation position, the beam current measuring instrument (P) includes a measuring portion (C) and a shield (S) disposed around the measuring portion (C), and the shield (S) includes: a Front Shield (FS) having an opening (H) for passing a part of the ion beam (3) to the measurement unit (C); a rear shield (BS) disposed at a position opposite to the Front Shield (FS); a Side Shield (SS) is disposed at a position other than the Front Shield (FS) and the rear shield (BS), and has a door (D) that can be opened and closed on a wall surface of a vacuum chamber (8) of an ion beam irradiation apparatus (1), and the door (D) also serves as the rear shield (BS).

Description

Ion beam irradiation apparatus

Technical Field

The present invention relates to an ion beam irradiation apparatus having a beam current measuring instrument for measuring a beam current of an ion beam.

Background

The ion implantation apparatus and the ion milling apparatus, etc., have a beam current measuring instrument for measuring a beam current of an ion beam irradiated to a substrate.

For example, in an ion implantation apparatus described in patent document 1, a faraday cup is disposed at a position where an ion beam is irradiated in a processing chamber where a substrate is processed or in an ion beam transport path in the middle of the processing chamber.

In general, as in the beam current measuring instrument shown in patent document 2, the periphery of a measurement unit for measuring a beam current, such as a faraday cup described in patent document 1, is covered with a shield or the like except for a specific portion through which an ion beam passes. The shield is provided for preventing electrons unnecessary for measurement (hereinafter referred to as unnecessary electrons) floating around the beam current measuring instrument from flowing into the measuring portion.

Maintenance of the components constituting the beam current measuring instrument is required, for example, for replacement of the components due to change over time.

For example, since the measuring unit of the beam current measuring instrument is irradiated with the ion beam, the measuring unit is sputtered with the ion beam and consumed with the passage of time. If the consumption becomes large, the component is replaced.

When the replacement is performed, the ion beam irradiation apparatus is entered, and the measurement unit is replaced after the mask of the beam current measuring instrument is removed, or if the beam current measuring instrument is small and lightweight, the beam current measuring instrument is carried to the outside of the ion beam irradiation apparatus, and then the mask of the beam current measuring instrument is removed and the measurement unit is replaced.

In order to avoid erroneous measurement of the ion beam due to unnecessary electrons, a shield surrounding the periphery of the measurement portion is necessary, but the replacement operation of the measurement portion requires a removal operation of removing the shield, and therefore the replacement operation of the measurement portion becomes complicated.

In addition to the trouble of removing the protection cover due to the replacement of the measuring portion, the trouble of removing the protection cover also occurs in maintenance work for other components arranged in the protection cover.

Documents of the prior art

Patent document 1: japanese patent laid-open publication No. 2006-196351

Patent document 2: japanese laid-open patent publication No. 2008-128660

Disclosure of Invention

The invention provides an ion beam irradiation device which simplifies the maintenance operation of a beam current measuring instrument.

The present invention provides an ion beam irradiation apparatus having a beam current measuring instrument fixed at an ion beam irradiation position, the beam current measuring instrument including: a measuring section; and a shield disposed around the measurement portion, the shield including: a front shield having an opening for passing a portion of the ion beam to the measurement portion; a rear shield disposed at a position opposite to the front shield; and a side shield disposed at a position other than the front shield and the rear shield, wherein a door capable of opening and closing is provided on a wall surface of a vacuum chamber of the ion beam irradiation apparatus, and the door also serves as the rear shield.

By using the door also as the rear face guard, part of the operation of the maintenance operation can be shared, and the maintenance operation of the beam current measuring instrument can be simplified.

In order to share the maintenance operation, the beam current measuring instrument may be fixed to the gate.

According to the above configuration, the operation of entering the apparatus and the operation of taking and placing the beam current measuring instrument can be shared.

Since the ion beam is irradiated to the beam current measuring instrument, the temperature of the shield of the beam current measuring instrument rises.

The side surface protection cover covering the longitudinal direction of the approximately rectangular parallelepiped beam current measuring instrument has a large amount of thermal deformation due to an increase in temperature of the protection cover, and a gap is formed between the side surface protection cover and the rear surface protection cover. Electrons may flow into the measurement portion through the gap.

In view of such a problem, it is preferable that the beam current measuring instrument has a substantially rectangular parallelepiped shape, and the rear surface protection cover or the side surface protection cover is provided with a permanent magnet along a longitudinal direction of the beam current measuring instrument.

According to the above configuration, even if a gap is formed between the side surface shield and the rear surface shield, unnecessary electrons passing through the gap can be captured by the magnetic field of the permanent magnet, and therefore, measurement using the beam current measuring instrument can be accurately performed.

A gap between the side shield and the rear shield, which is generated in the long-side direction of the beam current measuring instrument, may also be generated in the short-side direction. Since the gap in the short side direction is small compared with the gap in the long side direction, unnecessary electrons passing through the gap are small, but in order to perform high-precision measurement with the beam current measuring instrument, in addition to a configuration in which a permanent magnet is provided on a side surface shield or a rear surface shield along the long side direction of the beam current measuring instrument, a permanent magnet is provided on the rear surface shield or the side surface shield along the short side direction of the beam current measuring instrument.

The same effect can be achieved using electrodes other than permanent magnets. Further, both the permanent magnet and the electrode may be provided.

The beam current measuring instrument has a substantially rectangular parallelepiped shape as a configuration having electrodes, and the rear surface protection cover or the side surface protection cover is provided with electrodes for applying a negative or positive voltage along a longitudinal direction of the beam current measuring instrument.

As with the permanent magnet structure, electrodes may be provided in the short-side direction in addition to the long-side direction of the beam current measuring instrument.

In this case, in addition to the configuration in which the electrodes are provided on the side surface shield or the rear surface shield along the longitudinal direction of the beam current measuring instrument, the electrodes to which the negative or positive voltage is applied are provided on the rear surface shield or the side surface shield along the short direction of the beam current measuring instrument.

By using the door for entering the device as the rear face guard, a part of the operations related to the maintenance operation can be shared, and the maintenance operation of the beam current measuring instrument can be simplified.

Drawings

Fig. 1 is a plan view showing the entire ion beam irradiation apparatus.

Fig. 2 is an enlarged view of the processing chamber shown in fig. 1.

Fig. 3 is a modification of the arrangement of the beam current measuring instrument shown in fig. 2.

Fig. 4 is a perspective view showing a configuration example of the beam current measuring instrument.

Fig. 5 is a plan view showing a configuration example of the beam current measuring instrument having the permanent magnet.

Fig. 6 is a plan view showing a configuration example of the beam current measuring instrument having the electrode.

Fig. 7 is a plan view showing a configuration example of a beam current measuring instrument having both a permanent magnet and an electrode.

Description of the reference numerals

1 ion beam irradiation apparatus

8 vacuum chamber

P-beam current measurer

C measuring part

S protective cover

FS front shield

SS side protective cover

BS rear protective cover

D door

M permanent magnet

E electrode

Detailed Description

Fig. 1 is a plan view showing the entire ion beam irradiation apparatus 1. The XYZ axes are orthogonal to each other, and the relationship and direction of each axis are common to other figures described later.

The ion beam irradiation apparatus 1 of fig. 1 is a mass analysis type ion implantation apparatus. The ion implantation apparatus removes unnecessary ions from an ion beam 3 extracted from an ion source 2 by a mass analysis electromagnet 4 and an analysis slit 5, and then conveys the ion beam to a process chamber 6.

In the processing chamber 6, a substrate 7 (for example, a glass substrate, a silicon wafer, or the like) is reciprocally scanned in the X direction so as to cross the ion beam 3 by a substrate scanning mechanism (not shown), thereby performing ion implantation processing on the substrate 7.

Further, the size of the ion beam 3 is longer than the size of the substrate 7 in the Y direction, and the ion beam 3 can irradiate the entire surface of the substrate 7 when the substrate 7 is scanned in the X direction.

The ion source 2 and the mass analysis electromagnet 4 and other parts constituting the ion beam irradiation apparatus 1 are disposed under a vacuum atmosphere, and the above-described components are disposed inside the vacuum chamber 8.

The structure and size of the vacuum chamber 8 vary depending on the structure and size of the ion beam irradiation apparatus 1, and the vacuum chamber 8 is often configured by combining a plurality of chambers.

In the configuration shown in fig. 1, a beam current measuring instrument P for measuring a beam current is disposed at a position of the processing chamber 6 to which the ion beam 3 is irradiated.

In an ion implantation apparatus of a system in which a spot-shaped ion beam 3 is scanned by a magnetic field or an electric field on a transport path of the ion beam 3 reaching the processing chamber 6, a beam current measuring instrument P may be fixedly disposed near the vacuum chamber 8 on the beam transport path.

Fig. 2 is an enlarged view of the processing chamber 6 shown in fig. 1.

The beam current measuring instrument P includes a measuring unit C such as a faraday cup and a shield S surrounding the measuring unit C.

The shield S includes: a front shield FS having an opening for passing a part of the ion beam 3 to the measurement section C; a rear shield BS disposed at a position opposite to the front shield FS; and a side shield SS disposed at a position other than the above.

In the configuration of fig. 2, the front shield FS, the side shield SS, and the measuring unit C are installed on the floor of the processing chamber 6.

The ion beam irradiation apparatus 1 is provided with an openable and closable door D for maintaining the inside of the apparatus. In the present invention, the door D doubles as the rear shield BS. For example, the door D is rotated about the Y direction as a rotation axis. Since the door D is opened to the position shown by the broken line and the rear cover BS is inserted into the apparatus and removed, the maintenance operation of the beam current measuring instrument P can be simplified as compared with the case where each operation is performed independently.

The door D can be opened and closed by the turning operation shown in the figure, but may be opened and closed by sliding the door D in the X direction as long as the air tightness is maintained between the door D and the vacuum chamber 8 when the door D is closed.

The configuration shown in fig. 3 may be used to share the operation of the maintenance operation. In fig. 3, the front shield FS, the side shield SS, and the measuring part C are mounted on the rear shield BS.

In this configuration, the beam current measuring instrument P can be taken out of the processing chamber 6 by opening the door D. Conversely, by closing the door D, the beam current measuring instrument P can be placed inside the processing chamber 6.

In this way, since the operation of entering the processing chamber 6 and the operation of taking and putting the beam current measuring instrument P are shared, the maintenance operation of the beam current measuring instrument can be simplified.

Fig. 4 depicts a perspective view of the beam current measurer P illustrated in fig. 1 to 3. The beam current measuring instrument P has a substantially rectangular parallelepiped shape and includes a plurality of measuring units C arranged in the Y direction and a shield S (a side shield SS, a front shield FS, and a rear shield BS) surrounding each measuring unit C. The front face guard FS has openings H formed at positions corresponding to the respective measuring portions C.

The beam current measurer P is mainly used for measuring the beam current and the beam current density distribution of an elongated ion beam long in the Y direction.

The substantially rectangular parallelepiped shape is a structure including a rectangular parallelepiped shape, a flange portion for attaching the bundle current measuring instrument P, and the like in addition to the rectangular parallelepiped shape at the main body portion.

Since the ion beam 3 is irradiated to the beam current measuring instrument P, the temperature of the shield S constituting the beam current measuring instrument P rises.

The side shield SS covering the longitudinal direction (Y direction) of the beam current measuring instrument P has a large amount of thermal deformation due to an increase in the shield temperature. Due to thermal deformation of the side surface shield SS, a gap is formed between the side surface shield SS and the rear surface shield BS, and electrons flow into the measurement unit C from the gap, which hinders normal measurement.

Further, since the rear shield BS also serves as a wall surface of the vacuum chamber 8, the thickness dimension is larger than that of the side shield SS, and therefore the amount of thermal deformation of the rear shield BS is extremely small.

Although there is a possibility that the gap is also generated between the front shield FS and the side shield SS, if an electrode or the like to which a negative voltage for recovering electrons disclosed in patent document 2 is applied is disposed on the upstream side (the opposite side in the Z direction) of the measurement unit C, the electrons flowing through the gap are less likely to reach the measurement unit C.

The unnecessary electrons include, for example, secondary electrons generated by collision between the ion beam 3 and the front shield FS, and electrons supplied to the substrate to be treated by ion beam irradiation for suppressing charging.

In the present invention, the structures shown in fig. 5 to 7 are used so as not to cause the unnecessary electrons to flow into the measurement section C.

In fig. 5, a permanent magnet M is disposed at the end of the side shield SS on the rear shield BS side. The permanent magnet M is a permanent magnet that is long in the Y direction (the longitudinal direction of the beam current measuring instrument P having a substantially rectangular parallelepiped shape) shown in the figure. If such a permanent magnet M is present, a magnetic field depicted by an arrow is formed in the gap between the side shield SS and the rear shield BS, and electrons can be prevented from flowing into the measurement portion C through the gap.

The structure and configuration of the permanent magnet M are not limited to those illustrated in fig. 5. For example, the arrangement of the magnetic poles arranged in SN in the Z direction may be reversed to NS. In addition, the magnetic poles may be arranged not in the Z direction but in the X direction, and any arrangement may be used as long as the magnetic poles form a magnetic field in the gap between the side shield SS and the rear shield BS.

The permanent magnet M disposed outside the shield S may be disposed inside the shield S. In addition, the permanent magnet M may be disposed between the side shield SS and the rear shield BS, or the permanent magnet M may be disposed in the rear shield BS near the side shield SS. In addition, the permanent magnets M may be provided to both the side shield SS and the rear shield BS.

The permanent magnets M may be provided in the Y direction over the entire area of the side shield SS, but in the case where the gap between the side shield SS and the rear shield BS becomes large at a specific portion, the permanent magnets M may be provided only at the portion where the gap becomes large.

In the short side direction (X direction) of the beam current measuring instrument P, the gap generated between the side shield SS and the rear shield BS is smaller than the gap in the long side direction, but if electrons pass through the gap and adversely affect the measurement in the measuring section C, the permanent magnet M may be provided in the X direction as in the Y direction.

In the case where electrons supplied from the electron supply source G (electron gun or submerged plasma gun) illustrated in fig. 5 are from the right side of the figure with the ion beam 3 interposed therebetween, the permanent magnet M may be provided only on the side shield SS on the side close to the electron supply source G.

However, if the electrons are turned around to the opposite side, the permanent magnet M may be provided also on the side shield SS on the opposite side to the electron supply source G as shown in the drawing.

Fig. 6 shows an example of a structure in which an electrode E is used instead of the permanent magnet M in fig. 5. The electrode E is attached to the side shield SS via an insulating member not shown, and a positive or negative voltage is applied thereto.

Although there is a difference in attracting electrons to the electrode E or withdrawing electrons from the electrode E by applying a voltage of either positive or negative polarity, either polarity may be selected as long as electrons can be prevented from flowing into the measurement portion C through the gap between the side shield SS and the rear shield BS.

The electrode E may be disposed inside or outside the shield S, as in the permanent magnet M. The dimension of the electrode E in the Y direction may be the same as that of the side shield SS, but may be provided only at a position where the gap is large without being provided over the entire area of the side shield SS. In addition, the electrodes may be arranged in the longitudinal direction (Y direction) of the beam current measuring instrument P, or in the short direction (X direction).

In addition, the electrode E may be provided at a position other than the above-described position, which is the same as the position of the permanent magnet M described in fig. 5.

Fig. 5 and 6 show a structure having either one of the permanent magnet M and the electrode E, but may have both the permanent magnet M and the electrode E as shown in fig. 7.

In the structure having both the permanent magnet M and the electrode E, both can be used separately as described below.

If the permanent magnet M is demagnetized due to the temperature rise, the measurement result of the beam current measurer P changes. When it is determined from the change in the measurement result that a failure has occurred in capturing the unwanted electrons by the magnetic field of the permanent magnet M, the voltage is applied to the electrode E to capture or recover the unwanted electrons by the electric field.

Until the ion beam irradiation apparatus is maintained at a regular maintenance time next time, unnecessary electrons are captured or recovered by the electrode E, and the permanent magnet M is replaced at the regular maintenance time.

In this way, the ion beam irradiation apparatus is not stopped at irregular intervals, and therefore the apparatus operation rate is not lowered. Further, the consumed power can be smaller than that in the structure in which the voltage is applied to the electrode E from the beginning.

The arrangement of the permanent magnets M and the electrodes E shown in fig. 7 is merely an example, and various modifications of the arrangement of the permanent magnets M and the electrodes E described in fig. 5 and 6 may be combined.

In the embodiment of fig. 4, the beam current measuring instrument P has a plurality of measuring units C, but the number of measuring units C may be one.

In addition to the above, it is needless to say that various improvements and modifications can be made without departing from the scope of the idea of the present invention.

Claims

1. An ion beam irradiation apparatus is characterized in that the ion beam irradiation apparatus is provided with a beam current measuring instrument fixed at an ion beam irradiation position,

the beam current measurer includes:

a measuring section; and

a shield disposed around the measuring section,

the protection casing includes:

a front shield having an opening for passing a portion of the ion beam to the measurement portion;

a rear shield disposed at a position opposite to the front shield; and

a side shield disposed at a position other than the front shield and the rear shield,

the ion beam irradiation apparatus has a door capable of opening and closing on a wall surface of a vacuum chamber,

the door doubles as the rear shield.

2. The ion beam irradiation apparatus according to claim 1,

the beam current measurer has a substantially rectangular parallelepiped shape,

and permanent magnets are arranged on the rear protective cover or the side protective cover along the long side direction of the beam current measurer.

3. The ion beam irradiation apparatus according to claim 2,

and permanent magnets are arranged on the rear protective cover or the side protective cover along the short side direction of the beam current measurer.

4. The ion beam irradiation apparatus according to claim 1,

the beam current measurer has a substantially rectangular parallelepiped shape,

an electrode for applying a negative or positive voltage is provided along the longitudinal direction of the beam current measuring instrument on the rear shield or the side shield.

5. The ion beam irradiation apparatus according to claim 2,

6. The ion beam irradiation apparatus according to claim 3,

7. The ion beam irradiation apparatus according to claim 4,

electrodes for applying a negative or positive voltage are provided along the short side direction of the beam current measuring instrument on the rear shield or the side shield.

8. The ion beam irradiation apparatus according to claim 5,

9. The ion beam irradiation apparatus according to claim 6,