JP2001110344A - Ion beam processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a problem that, while thermal electrons within the range irradiated with ion beam are attracted by Ar+ ions to hit a screen (shutter), thermal electrons produced at the part of uncovered filament terminal portion reach a substrate with creeping phenomenon like reflection to lower the electri cal potential of the substrate. SOLUTION: The shutter 6 has such a structure that a projection 6A to shield a gap between a cover 14 and the shutter 6 is provided in projection from other peripheral portion 6B of the shutter 6, causing thermal electrons within the range irradiated by the ion beam are attracted by Ar+ ions to hit the shatter 6, whereas roundabout of thermal electrons produced at the part of uncovered filament terminal portion becomes to hardly reach the substrate 16 by stopping with the projection 6a, enabling to prevent potential of the substrate 16 from lowering and to make the processing chamber 3 smaller by the extent of contrivance by providing the projection 6A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion beam processing apparatus such as ion beam milling and ion beam sputtering, and more particularly to an ion beam processing apparatus equipped with a filament type neutralizer for neutralizing an ion beam using a filament. About.

[0002]

2. Description of the Related Art An ion beam milling apparatus includes an ion source for generating an ion beam by introducing Ar gas into plasma to generate an ion beam, a processing chamber having a substrate holding device for holding a substrate, and a vacuum exhaust device.

In an ion source, a high voltage is applied to an ion source electrode having a net-like shape made of metal, so that only Ar + ions are extracted from an Ar plasma to form an ion beam. Then, the substrate is charged to a positive potential. Therefore, an electron emitter called a neutralizer is provided between the ion source and the substrate holding device to electrically neutralize.

As a neutralizer, a so-called filament-type neutralizer is generally used, in which a heavy metal filament such as Ta or W is used to apply a voltage to both ends of the filament to cause the filament to glow to emit thermoelectrons. Can be For example, Hitachi Review (June 1986, Vol. 68 No.
In the large-diameter ion beam milling apparatus shown in 6), the filament wire used for the neutralizer is Ta of φ0.35 mm.
The potential difference applied to both ends is about 80 V, and the flowing current is about 10 A. Since a large current flows through both ends of the filament, a large-capacity current introduction terminal for introducing a current from the outside of the chamber to the terminal is used. The filament is attached by a fixture on the vacuum side of the current introduction terminal. The filament used in the neutralizer is arranged at the center of the irradiation range of the ion beam so that the electrons are emitted from the filament in a wide range. Because of this, the filament is directly exposed to the ion beam, so it is greatly consumed and needs to be replaced periodically. For this replacement work, the current introducing terminal and the fixture for fixing the filament can be easily removed and attached. In addition, as an example of using a filament in a processing device, a practically open flat type 2-3 is used.
No. 6150 and JP-A-64-57552.

The milling apparatus is mainly used in the field of magnetic head manufacturing, and employs a large-diameter ion source or a robot having a transfer mechanism by a robot so that more substrates can be processed simultaneously. I have. In recent years, in the field of manufacturing magnetic heads, MR (Magneto Res)
active) head or GMR (Giant Magn)
2. Description of the Related Art A multilayer thin film element called a magnetoresistive element such as an eto resistive head has been developed and generally used. Since these elements require an extremely thin film structure and fine processing, the withstand voltage of a substrate (wafer) on which a number of elements are arranged is low.

[0006]

The neutralizer filament of the milling device can be easily removed by using a fixing fitting used to connect both terminals of the filament and the current introducing terminal.
It was exposed in the processing chamber so that it could be mounted. When a voltage is applied to the filament terminal before and after the milling process, thermoelectrons are emitted by the red heat of the filament. At this time, the thermoelectrons in the irradiation range of the ion beam are attracted to the Ar + ions and impinge on the shielding plate (shutter), but the thermoelectrons generated at the exposed filament terminal portion are wrapped around by reflection or the like. As a result, the substrate reaches the substrate, and the potential of the substrate decreases. This reduction is about 60% of the potential applied to the filament terminal portion.

SUMMARY OF THE INVENTION An object of the present invention is to suppress fluctuations in the potential of a substrate before and after milling, and to form a thin film requiring high-precision processing or to process a processing substrate having fine wiring. It is to provide a beam processing device.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a substrate holding device for holding a substrate, and the substrate holding device is housed and connected via a vacuum exhaust device. A filament that neutralizes the ion beam generated by the ion source, comprising a processing chamber chamber and an ion source that converts the introduced gas into plasma and extracts ions in the plasma by an extraction electrode to generate an ion beam. In an ion beam processing apparatus provided with a filament type neutralizer for emitting thermoelectrons using a part of a processing chamber, a shutter plate covering a filament is attached to a part of the processing chamber. In the processing equipment.

According to a second aspect of the present invention, a current introducing terminal connected to the filament is connected to one end of the filament type neutralizer, and a cover for covering the current introducing terminal and the filament is provided in a part of the processing chamber. An ion beam processing apparatus is characterized in that a shutter plate that covers a filament exposed portion is attached.

According to a third aspect of the present invention, a current introducing terminal connected to the filament is connected to one end of the filament type neutralizer, and a cover for covering the current introducing terminal and the filament is provided in a part of the processing chamber, and the remaining portion is provided. An ion beam processing apparatus is characterized in that a shutter plate that covers an exposed portion of a filament is attached, and a protruding portion that protrudes from another portion of the shutter plate is provided so as to wrap a part of the shutter plate on a cover.

According to a fourth aspect of the present invention, the filament is connected in a V-shape between at least one or more filament terminals provided at one end of the filament and at least two or more filament terminals provided at the other end. And an ion beam processing apparatus.

According to a fifth aspect of the present invention, the filament is connected in a V-shape between at least one or more filament terminals provided at one end of the filament and at least two or more filament terminals provided at the other end. The ion beam processing apparatus according to any one of claims 1 to 3, wherein:

According to a sixth aspect of the present invention, the terminals at both ends of one or a plurality of filaments are made to have the same potential, and a potential difference is applied to a middle point to electrically form a parallel circuit. Item 4. The ion beam processing apparatus according to any one of Items 1 to 3.

That is, according to the present invention, the following structure is applied to an ion beam milling apparatus.

(1) A cover for covering a portion to which a voltage is applied is attached to both ends of the filament to suppress emission of surplus electrons.

(2) A shutter plate for shielding the ion beam irradiated from the ion source before and after the process not only covers the ion source but also covers the filament terminal portion.

(3) In order to reduce the potential difference applied to the filament terminals, a structure is used in which a plurality of filament wires are used, and an electrically parallel circuit is formed. Alternatively, terminals at both ends of the neutralizer filament are set to the same potential, and a potential difference is applied to the middle point to electrically configure a parallel circuit.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1 is a schematic view of an ion beam milling apparatus, FIG. 2 is an enlarged view showing details of a voltage applying unit of a neutralizer filament, FIG. 5 is a schematic view showing a shutter plate shape, and FIG. 4 shows an embodiment of the present invention. FIGS. 5 to 7 are perspective views of the shutter plate shape, and FIGS. 5 to 7 are wiring diagrams of filaments.

The ion beam milling apparatus shown in FIG. 1 mainly comprises an ion source 1 for generating an ion beam, a processing chamber 3 to which one end of a substrate holding device 2 is mounted, an evacuation device 4, and the like. In addition, when the ion source power is turned on before and after the milling process or when the neutralizer power is turned on, the ion source 1 is turned on.
In order to prevent the substrate 16 from being irradiated with the ion beam from the substrate 16, a shielding plate called a shutter plate 6 is provided between the neutralizer 5 and the substrate holding device 2 downstream of the ion source 1 in one of the processing chambers 3. Prepared in the department. The substrate 16 is operated externally so as to form an inclined surface by operating the operation shaft 16A.

In the ion source 1, an ion source chamber 7;
A gas inlet 8 for introducing Ar gas, and A
An ion source filament 9 for converting r gas into plasma, an ion source electrode 10, etc., and a circular φ250 ion source electrode 10 includes an acceleration electrode 10A and a deceleration electrode 10B.
And By applying a high voltage to the acceleration electrode 10A, Ar + ions are extracted to generate an ion beam. The deceleration electrode 10B functions to block the electrons of the Ar gas that has been turned into plasma. The ion source 1 is mounted on the outer wall of the processing chamber 3 so as to match the hole formed in the processing chamber 3.

A neutralizer 5 necessary for neutralizing the ion beam is mounted immediately downstream of the ion beam, that is, on the inner wall of the processing chamber 3 opposite to the ion source mounting surface.
A current for causing the filament 11 for neutralization to glow red is supplied by attaching a current introduction terminal 12 to a hole provided in the processing chamber 3 above and below the hole of the ion source 1. As shown in FIG. 2, a fixing bracket 13 for fixing the filament 11 is attached to the vacuum end of the current introduction terminal 12, and the filament fixing bracket 13 can be easily removed and attached by a knurled screw structure. It has become.

As shown in FIG. 3, a cover 14 for preventing excessive emission of electrons from the filament 11 is attached so as to cover the entire portion fixed to the current introduction terminal 12 from the end of the irradiation range of the ion beam. The structure is designed to be hooked by the pins 15 (see FIG. 2) on the inner wall of the processing chamber and is not completely fixed, so that the effect of thermal deformation due to radiant heat from the filament 11 is suppressed and the structure can be easily removed at the same time. In addition, it prevents the surplus electrons from the projecting current introduction terminal 12 from irradiating the substrate 16.

At the stage before and after the milling process, the ion beam 17 from the ion source 1 is shielded by the shutter plate 6 so that the ion beam 17 does not reach the substrate 16. By turning around, the space between the opening of the cover 14 and the shutter plate 6 is removed and the substrate 1
6, the shutter plate 6 is provided with a protruding portion 6A for closing the gap between the cover 14 and the shutter plate 6 as shown in FIG. Structured.

As described above, the thermoelectrons in the irradiation range of the ion beam are attracted to the Ar + ions and strike the shutter plate 6, but the thermoelectrons generated at the exposed filament terminal portion are wrapped around by reflection or the like. Is prevented by the protruding portion 6A, it is difficult to reach the substrate 16, and without reducing the potential of the substrate 16, for example, when the substrate 16 has an insulating film, dielectric breakdown due to the Minau potential can be prevented, Variations in the potential of the substrate before and after the milling process can be suppressed, and a thin film requiring high-precision processing can be formed and a substrate having fine wiring can be processed. Reference numeral 18 denotes a current flowing through the filament 11.

In order to prevent the surplus electrons from the projecting current introduction terminal 12 from irradiating the substrate 16, even if the shutter plate 6 is extended to a position where the current introduction terminal 12 is closed, the substrate 16 has The effect of preventing the potential from lowering can be achieved.

Further, the current introduction terminal 12 and the filament 1
1 and a shutter plate 6 that shields the filaments 11 other than the cover 14. If not shared, the processing chamber 3 must be enlarged so as not to collide with the inner wall of the processing chamber 3 when the shutter plate 6 rotates, but in the case of the present invention, the shutter is shared. The rotation distance of the plate 6 is shorter than when it is not shared, and the processing chamber 3 can be reduced in size.

Further, by providing only the protruding portion 6A, the closed shutter plate 6 operates the operating shaft outside the processing chamber chamber 3 to move the rod 6D through the fulcrum 6C in the arrow direction C (or from the chain line). When the shutter plate 6 is opened by rotating the shutter plate 6 (solid line), the other outer peripheral portion 6B is in the position indicated by the dashed line,
Although the dimension of the processing chamber 3 from the front side to the rear side increases, eventually the volume of the processing chamber 3 increases, and the processing chamber 3 becomes large. Only the processing chamber 3 can be reduced.

Next, the neutralizing filament 11 will be described. Conventionally, a single Ta wire is used for the filament 11, but this is increased to a plurality of lines to form a parallel circuit. The electrons reach the substrate 16 due to reflection or the like,
Since the potential when charged is about the voltage applied to the filament terminal portion, the potential of the filament terminal portion can be suppressed by forming a parallel circuit with a plurality of filaments, and the potential of the substrate 16 can be suppressed at the same time.

Further, in the embodiment shown in FIG. 5, two filament wires 11A are used and are electrically connected in parallel. In the embodiment shown in FIG. 6, one filament wire is
1B, and are connected in parallel by applying a potential difference between the middle point and the terminals at both ends. Further, in the embodiment shown in FIG. 7, a W-shaped 11C, which is a combination of two V-shaped 11Bs, is wired for one filament wire, and the same potential difference is applied to each length to establish a parallel connection.

At this time, if the filament wire diameter is the same as the conventional one, the resistance becomes small and the amount of emitted thermoelectrons is reduced. Therefore, it is necessary to make the filament wire thin. In the embodiments shown in FIGS. 5 to 7, a current of 5 A is applied to each using a Ta line thinner than the conventional one. The potential applied to both ends of the filament at this time is approximately 0
V, -20 V, which can be halved compared to the potential difference of 40 V in the conventional single wiring.

[0031] Especially when using the V-shaped filament wire 11B of FIG. 6 and FIG. 7, for example, one end of the filament wire is fixed to the left side terminals X ₁ in FIG. 7, right terminal entwined in middle terminal X ₂ and the other end because it so as to fix at X _3, since good for one filament wire 11, the working efficiency is good.

[0032]

As described above, according to the present invention, thermoelectrons and the wraparound of thermoelectrons within the irradiation range of the ion beam are:
With the shutter plate and the cover and the shutter plate, it can be prevented from reaching the substrate because it can be prevented, and without lowering the potential of the substrate, for example, when the substrate has an insulating film, it is possible to prevent insulation breakdown due to negative potential, Variations in the potential of the substrate before and after the milling process can be suppressed, and a thin film requiring high-precision processing can be formed and a substrate having fine wiring can be processed.

Further, by covering the current introduction terminal and the neutralizer filament with the cover and the shutter plate, the processing chamber can be miniaturized. Further, the processing chamber can be reduced in size by providing a projecting portion on the shutter plate.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an ion beam milling apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing details around a neutralizer filament of FIG. 1;

FIG. 3 is a perspective view showing the vicinity of a neutralizer filament and an ion source electrode of FIG. 1;

FIG. 4 is a perspective view showing the shutter plate of FIG. 1;

FIG. 5 is a wiring diagram of the filament used in FIG. 1;

FIG. 6 is a wiring diagram of a filament showing another embodiment of the present invention.

FIG. 7 is a wiring diagram of a filament showing another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ion source, 2 ... Substrate holding device, 3 ... Processing chamber chamber, 4 ... Vacuum exhaust device, 5 ... Neutralizer, 6 ... Shutter plate,
6A: projecting portion, 6B: other outer peripheral portion, 7: ion source chamber, 8: gas inlet, 9: ion source filament, 1
0: ion source electrode, 11: filament, 12: current introduction terminal, 13: filament fixing bracket, 14: filament terminal cover, 15: cover mounting pin, 16: substrate, 17: ion beam, 18: current.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroo Okawa 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Inside the Kokubu Office of Hitachi, Ltd. No. 1-1 F-term in Hitachi Kokubu Office (reference) 4K029 DA12 DC37 5C030 BB02 5C034 CC07 CC13 5F004 AA06 BA11 BB18 BC08 DA23

Claims (6)

[Claims] 1. A substrate holding device for holding a substrate, a processing chamber containing the substrate holding device and connected via an evacuation device, and the introduced gas is turned into plasma, and ions in the plasma are extracted by an extraction electrode. A filament-type neutralizer that emits thermoelectrons by using a filament that electrically neutralizes the ion beam generated by the ion source. In the ion beam processing equipment prepared for
An ion beam processing apparatus, wherein a shutter plate covering a filament is attached to a part of a processing chamber. 2. A substrate holding device for holding a substrate, a processing chamber containing the substrate holding device and connected via an evacuation device, and the introduced gas is turned into plasma, and ions in the plasma are extracted by an extraction electrode. A filament type neutralizer that emits thermoelectrons using a filament that electrically neutralizes the ion beam generated by the ion source. In the ion beam processing apparatus provided, a current introduction terminal connected to the filament is connected to one end of the filament type neutralizer, and a cover for covering the current introduction terminal and the filament in a part of the processing chamber, and the remaining filament exposed portion is An ion beam processing apparatus comprising a shutter plate for covering. 3. A substrate holding device for holding a substrate, a processing chamber containing the substrate holding device and connected to a vacuum exhaust device via a gate valve, and converting the introduced gas into plasma, and using an extraction electrode to generate plasma. A filament-type neutralizer, which consists of an ion source that extracts ions inside to generate an ion beam and emits thermoelectrons using a filament that electrically neutralizes the ion beam generated by the ion source, is provided in the processing chamber. In a partially provided ion beam processing apparatus, a current introduction terminal connected to a filament is connected to one end of a filament type neutralizer, a cover covering the current introduction terminal and the filament is provided in a part of the processing chamber, and the remaining filament is Attach a shutter plate that covers the exposed portion, and wrap the shutter plate over the cover so that a part of the shutter plate is An ion beam processing apparatus comprising a protruding projection. 4. A substrate holding device for holding a substrate, a processing chamber containing the substrate holding device, connected to a vacuum exhaust device via a gate valve, and converting the introduced gas into a plasma. And a filament neutralizer that emits thermoelectrons using a filament that electrically neutralizes the ion beam generated by the ion source. In the ion beam processing apparatus provided in the portion, the filament is connected in a V-shape between at least one or more filament terminals provided at one end of the filament and at least two or more filament terminals provided at the other end. An ion beam processing apparatus characterized by the above-mentioned. 5. The filament is connected in a V-shape between at least one or more filament terminals provided at one end of the filament and at least two or more filament terminals provided at the other end. Item 4. The ion beam processing apparatus according to any one of Items 1 to 3. 6. The parallel circuit according to claim 1, wherein both terminals of one or a plurality of filaments have the same potential, and a potential difference is applied to a middle point to form an electrically parallel circuit.
The ion beam processing apparatus according to any one of the above.