JP3419331B2 - Ion milling apparatus, ion milling method, ion beam irradiation apparatus, and ion beam irradiation method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention extracts ions in plasma generated in an ion source chamber as an ion beam by an extraction electrode and mills the surface of a workpiece such as a substrate in the manufacturing process of a thin film magnetic head or the like. And an ion milling method. The present invention also relates to an ion beam irradiation apparatus and an ion beam irradiation method used for an ion milling apparatus, an ion beam vapor deposition apparatus, a sputter vapor deposition apparatus, an ion implantation apparatus, or the like.

[0002]

2. Description of the Related Art For example, in a manufacturing process of a thin film magnetic head used for a magnetic disk for a computer, an ion milling device is used for processing a head constituent layer.
This conventional ion milling device is disclosed in, for example, Japanese Patent Laid-Open No. 8-
As disclosed in Japanese Patent No. 8230 and Japanese Patent Laid-Open No. 9-41165, an ion source chamber for converting introduced gas into plasma and confining it, and an extraction electrode for extracting ions in plasma in the ion source chamber as an ion beam And a processing chamber chamber that mills the surface of the substrate by the ion beam emitted from the irradiation device. The extraction electrode is composed of an accelerating electrode and a decelerating electrode that are arranged to face each other.

A substrate holder for holding a substrate is provided in the processing chamber chamber, and a plurality of substrates can be continuously processed by sequentially attaching and detaching the substrate to be processed to and from the holder. Has been done.

[0004]

When ion milling is performed by the above-mentioned conventional apparatus, when the substrates to be processed are processed immediately after the apparatus is started, the first several sheets (about 6 sheets in the trial of the inventors of the present application) are processed. It is known that machining is unstable and overmilling or milling residue occurs. Therefore, when the conventional device is used, the dummy substrate is mounted on the substrate holder and the device is pre-milled for idle operation before the substrate to be processed is milled, but stable milling can be performed. It is necessary to carry out pre-milling for 30 minutes or more before the time becomes, as shown in FIG.

When the substrates are continuously processed, premilling may be performed and stabilized before processing the first substrate, but when the processing interval is one hour or more, premilling is performed again. Therefore, there is a problem that productivity is poor.

Therefore, the present invention provides an ion milling apparatus and method capable of stabilizing the milling process of a workpiece without performing premilling, and also an ion beam capable of stabilizing the ion beam. An object is to provide an irradiation device and method.

[0007]

As a result of earnest studies by the inventors of the present application, the above-mentioned problem is that the extraction electrode is distorted by the plasma in the ion source chamber, the heat of a neutralizer, etc. It was found that the extracted ion beam became unstable, and the velocity and distribution of the ion beam fluctuated. Therefore, after starting the device,
By rapidly moving the electrode to a thermally stable state or eliminating the distortion of the electrode due to the control of the temperature difference due to the electrode site, the velocity and distribution of the ion beam are stabilized, and the workpiece such as the substrate is processed. It is thought that the milling process of the object will be stabilized from the beginning.

The present invention made based on such an idea is as follows.
In an ion milling device equipped with an electrode for extracting ions in plasma generated in an ion source chamber as an ion beam, the extraction electrode is plate-shaped and
Heats the periphery of the pole to reduce the temperature difference between the periphery and the center.
It is characterized in that a heater for reducing or reversing is provided.

According to the ion milling apparatus of the present invention, the extraction electrode is heated by the heater before the milling, so that the extraction electrode is rapidly transferred to a thermally stable state. Therefore, when the workpiece is processed, the temperature of the extraction electrode does not change significantly, and the deformed shape due to thermal expansion is almost determined, so that the velocity and distribution of the ion beam extracted by the electrode are stable. Therefore, it is possible to prevent overmilling or insufficient milling from occurring in the processing of the first several workpieces (such as substrates) after the apparatus is started.

The target temperature of the extraction electrode due to heating is
Make the temperature equal to the electrode temperature after the start of milling. In order to detect that the electrode has reached the target temperature, it is preferable to provide a temperature sensor on the extraction electrode and to provide control means for controlling the device according to the electrode temperature detected by the temperature sensor.

Further, even if the heater is not heated before the milling, the peripheral portion of the extraction electrode is heated by the heater during the milling by the ion beam irradiation, so that the central portion of the extraction electrode in a thermally stable state can be obtained. The temperature difference from the peripheral portion can be reduced or reversed, and the amount of flexural deformation of the extraction electrode can be reduced or eliminated, which makes it possible to control the distribution of the ion beam for milling.

The heater may be one that heats the peripheral portion of a plate-shaped (generally disc-shaped) extraction electrode provided with a large number of apertures. Such a heater may be attached to the peripheral portion of the electrode or may be arranged near the peripheral portion. If the heater is provided at the peripheral edge of the electrode as described above, the extraction of the ion beam from the aperture is not hindered, and the extraction electrode can be heated quickly by heating the extraction electrode by direct contact.

The heater for heating the peripheral edge of the electrode may be formed in a ring shape over the entire peripheral edge of the extraction electrode, or a plurality of heaters may be attached to the peripheral edge of the extraction electrode at predetermined intervals. Although various materials such as molybdenum and carbon can be used as the material of the plate-like electrode, molybdenum having a high heat resistance temperature, a small thermal expansion coefficient, and good strength and workability is suitable. As the heater, a silicon rubber heater, an electric heater,
A ceramic heater or the like can be used. In addition,
The silicon rubber heater has a coil coated with silicon rubber having a thickness of about 1 mm.

As the extraction electrode, an acceleration electrode and a deceleration electrode are usually provided. The acceleration electrode is located on the ion source chamber side, and the deceleration electrode is located on the processing chamber chamber side. Further, a positive voltage is applied to the accelerating electrode, an electric field swelling toward the ion source chamber side is generated in the aperture of the accelerating electrode, and a negative voltage is applied to the decelerating electrode, and the aperture of the decelerating electrode is An electric field bulging toward the processing chamber chamber side is generated. Since the aperture of the acceleration electrode and the aperture of the deceleration electrode correspond to each other, the electric field generated in these apertures constitutes an electric field lens. By this electric field lens, the ejection direction of the ions passing through the aperture is corrected to a direction substantially perpendicular to the plate surface of the electrode. Therefore, in this type of extraction electrode, the relative positional relationship between the apertures of the acceleration electrode and the deceleration electrode is extremely important for determining the direction of the ion beam.

Here, when the acceleration electrode and the deceleration electrode have a flat plate shape, it is considered that these electrodes are slightly curved due to thermal expansion, but there is no guarantee that the acceleration electrode and the deceleration electrode are curved in the same direction. If each electrode bends in a different direction,
The relative distance between the apertures of the respective electrodes fluctuates so as to affect the control of the ion beam.

Therefore, it is preferable that the acceleration electrode and the deceleration electrode are curved in the same direction in advance. Such bending can be performed by, for example, an annealing process. The radius of curvature of each electrode is preferably 5 m or more and 10 m or less.

The heater can be attached directly to both the acceleration electrode and the deceleration electrode, or an electrothermal heater can be embedded and heated in a member supporting the peripheral edge of the electrode.

Further, according to the present invention, in an ion beam irradiation apparatus provided with an extraction electrode for extracting ions in plasma generated in an ion source chamber as an ion beam, the extraction electrode is heated so that a peripheral portion and a central portion are formed. Temperature difference
It is characterized in that a heater for reducing or reversing is provided.

According to the ion beam irradiation apparatus of the present invention, the extraction electrode is heated by the heater before the beam irradiation is started, so that the extraction electrode is rapidly transferred to a thermally stable state. Therefore, the temperature of the extraction electrode does not change significantly during beam irradiation, and the deformed shape due to thermal expansion is almost determined, so that the velocity and distribution of the ion beam extracted by the electrode are stable.

Further, according to the above-mentioned ion beam irradiation apparatus, it is also possible to heat the peripheral portion of the extraction electrode by the heater during beam irradiation, which allows the center and the peripheral edge of the extraction electrode in a thermally stable state. The temperature difference with the portion can be reduced or reversed, and the amount of flexural deformation of the extraction electrode can be reduced or eliminated. This also makes it possible to stabilize the beam by controlling the beam distribution and the like in the ion beam irradiation.

The extraction electrode and the heater of such an ion beam irradiation device can be constructed in the same manner as in the case of the above-described ion milling device, and almost the same action can be obtained.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

The ion milling apparatus 1 according to the first embodiment of the present invention shown in FIGS. 1 and 2 constitutes an alumina film, a magnetic film constituting a magnetic core, and a coil in a manufacturing process of a thin film magnetic head, for example. In addition to a copper film, a gold film, a chromium film, an AlTiC substrate, and various resists are milled. In the manufacture of the thin film magnetic head, individual thin film magnetic heads are obtained by cutting a plurality of heads having a predetermined structure aligned on a disc-shaped Altic substrate.

The ion milling apparatus 1 has an ion source chamber 2 provided with a plasma generating means, and Ar ions (Ar ions in Ar plasma in the ion source chamber 2).
An extraction electrode 3 for extracting +) as an ion beam, and a processing chamber chamber 5 for milling the surface of a substrate 4, which is a workpiece, by the ion beam are provided. The processing chamber chamber 5 communicates with the ion source chamber 2, and these chambers 2 and 5 form a vacuum chamber. That is, the processing chamber 5 is provided with an exhaust port 6 connected to a vacuum pump (not shown), and the gas in the ion source chamber 2 and the processing chamber 5 is evacuated by the vacuum pump.

The ion source chamber 2 has a bottomed cylindrical shape with one side (the right side in FIG. 1) opened, and a large number of magnets 7 are adjacent to each other on the outer surface side of the chamber 2. Magnetic poles are alternately arranged, and these magnets 7 form a Kaps magnetic field as shown in FIG. 1 near the inner wall of the internal space of the chamber 2. This Kapus magnetic field is for confining the plasma in the chamber 2 by the wall of the magnetic field line so that the high temperature Ar plasma does not directly contact the inner wall of the ion source chamber 2.

The plasma generating means includes a gas supply device 8 for supplying Ar gas into the ion source chamber 2, a filament 9 made of tungsten or the like for emitting thermoelectrons into the space inside the chamber 2, and both ends of the filament 9. The power supply device 10 applies a required voltage, and the arc power supply device 11 applies an arc voltage between the ion source chamber 2 and the negative terminal of the filament 9. The gas supply device 8 includes a gas tank 12 and a mass flow controller (MFC) 13.

The extraction electrode 3 is the ion source chamber 2
Attached to the opening of the ion source chamber 2
Ar ions can be extracted as an ion beam from the Ar plasma inside. Thus, the extraction electrode 3, the ion source chamber 2, and the plasma generator constitute an ion beam irradiation device 31.

The extraction electrode 3 of this embodiment comprises an acceleration electrode 15 and a deceleration electrode 16. Each of the acceleration electrode 15 and the deceleration electrode 16 is a disc-shaped molybdenum plate having a thickness of 1 mm, and a large number of apertures 17 (holes) are uniformly provided over substantially the entire surface. The acceleration electrode 15 and the deceleration electrode 16 are opposed to each other with a predetermined space therebetween, and the apertures 17 of the electrodes 15 and 16 are aligned with each other. Further, the acceleration electrode 15, the deceleration electrode 16, the ion source chamber 2 and the processing chamber 5 are all electrically insulated. Although it can be formed of a material other than molybdenum, molybdenum has a high heat resistance temperature and a small thermal expansion coefficient, and is therefore a preferable material for the extraction electrode exposed to a high temperature.

The acceleration electrode 15 and the deceleration electrode 16 are
In each case, the central portion is slightly curved so as to bulge toward the processing chamber 5 side. The radius of curvature depends on the size of the entire device, but is 3 m to 20 m, preferably 5 m.
It is set to m or more and 10 m or less.

Silicon rubber heaters 18 are attached to the peripheral portions of the acceleration electrode 15 and the deceleration electrode 16.
The heater 18 is heated by the power supply from the power supply device 19. In the illustrated embodiment, the heater 18 is formed in a ring shape over substantially the entire circumference of the acceleration electrode 15 and the deceleration electrode 16, and is attached to both surfaces of each of the electrodes 15 and 16. It is configured so as to sandwich the peripheral edge portion of the deceleration electrode 16.

The ion beam irradiation device 31 is equipped with a power supply device 20 for applying a positive voltage to the acceleration electrode 15 and a power supply device 21 for applying a negative voltage to the deceleration electrode 16.
The ion beam is controlled by the amount of voltage applied by these power supply devices 20 and 21.

Further, the acceleration electrode 15 is connected to the ion source chamber 2 via a resistor 22 of 500Ω.

In the processing chamber chamber 5, a holder 23 for holding the substrate 4, which is a workpiece, is provided. The holder 23 is provided in the irradiation area of the beam irradiation device 31, and the surface of the substrate 4 held by the holder 23 can be milled.
Further, the holder 23 is connected to the ground 24.

The ion milling apparatus 1 of this embodiment is also used.
Is provided with a neutralizer 25 (neutralizing device) for neutralizing electric charges on the surface of the workpiece 4 during milling, and a shutter 28 that can be opened and closed. The neutralizer 25 includes a filament 26 arranged near the machining chamber chamber side of the extraction electrode 3 and a power supply device 27 that supplies power to the filament 26. When a voltage is applied across the filament 26 to heat it, thermoelectrons are generated from the filament 26, the electrons neutralize the Ar ion beam in a charge manner, and the workpiece 4 is prevented from being charged up. In addition,
The filament of the neutralizer 25 is connected to the acceleration electrode 15
It can also be arranged between the deceleration electrode 16 and the deceleration electrode 16.

Each power supply device 10, 11, 19, 27
The operations of the shutter 28, the gas supply device 8 and the like are controlled by a control signal from the control device 28.

Here, the operation of the ion beam irradiation device 31 will be described.

When a filament voltage Vfil is applied and a current is passed through the filament 9, the filament becomes red and thermoelectrons e (electrons) are generated. The number of the thermoelectrons e generated is determined by the filament 9 as shown in the following equation (1).
It is increased by increasing the amount of current flowing through.

[0038]           Quantity of e = K · Vfil 3/2 ・ ・ ・ Equation (1)

K is a proportional constant.

Filament 9 when thermoelectrons e are emitted
Since the temperature of the (tungsten wire) is 1000 ° C. or higher, a water-cooling introduction terminal is used for the terminal 14 of the filament 9 to cool the filament 9.

With a large number of thermoelectrons e being emitted into the ion source chamber 2, a small amount of Ar gas is supplied into the chamber 2 and an arc voltage is applied between the ion source chamber 2 and the negative terminal of the filament 9. , Arc discharge is generated, the Ar molecules collide violently with the thermoelectrons e, and the Ar molecules are ionized to change into Ar ions. The reaction formula is shown in the following formula (2).

[0042]           e + Ar = 2e + Ar + (2)

As a result, Ar ions (Ar +), electrons (e), and Ar molecules that have not been ionized are mixed in the ion source chamber 2, and as a whole, electrically neutral plasma is generated.

When the acceleration voltage of 600 V is applied to the acceleration electrode 15 in the state where the Ar plasma is generated in this way, the plasma is raised to the potential of 600 V through the resistor 22. At the moment when Ar ions in the plasma drop from the aperture of the accelerating electrode 15 to the processing chamber 5 side, the Ar ions are accelerated at 600 V and vigorously jump out toward the holder 23 connected to the ground. The Ar ion beam is generated by the bundle of Ar ions. Then, the substrate 4 held by the holder 23 can be scraped by Ar ions.

Further, for example, -200V is applied to the deceleration electrode 16.
When the voltage is applied, the aperture of the accelerating electrode 15 and the aperture of the decelerating electrode 16 form an electric field lens, the trajectory of the ion ejection direction is corrected, and the ion beam is made to travel substantially straight.

According to the ion beam irradiation apparatus 31 of the ion milling apparatus 1 according to the above embodiment, the acceleration electrode 1
5 and the heater 18 are attached to the peripheral portions of the deceleration electrode 16 and the acceleration electrode 15 and the deceleration electrode 16 before the milling.
As it can be heated rapidly from 0 to 240 degrees,
As shown in, the extraction electrode 3 can be in a thermally stable state at the time of processing the first substrate, the milling process can be stabilized, and overmilling or insufficient milling occurs. Can be prevented.

FIG. 6 shows an ion implantation apparatus equipped with an ion beam irradiation apparatus according to the second embodiment of the present invention. This ion implantation apparatus is used, for example, in a process of manufacturing a flat panel display, in a process of implanting impurities into a semiconductor thin film for the purpose of forming a thin film transistor.

One of the differences between the ion beam irradiation apparatus according to this embodiment and the ion beam irradiation apparatus according to the first embodiment in terms of device configuration is that the acceleration electrode 15 and deceleration electrode 1
The heater for heating the extraction electrode 3 composed of 6 is a filament 18 provided in the ion source. The filament 18 provided as a heater for heating the extraction electrode 3 has a thickness and a length larger than those of the filament 9 for generating arc plasma, so that power can be supplied several times as much. There is.
The filament 18 is arranged in the ion source chamber 2. The filament 18 is connected to the extraction electrode 3
It has a ring shape along the peripheral edge of the extraction electrode 3 and is arranged in the vicinity of the peripheral edge of the extraction electrode 3 to heat the peripheral edge of the extraction electrode 3.

Further, the ion beam irradiation apparatus according to this embodiment is different from the ion beam irradiation apparatus according to the first embodiment in the attachment structure of the extraction electrode. That is, the ion source chamber 2 is divided into a back surface portion 2a and a side surface portion 2b, and an acceleration flange 44 having an opening slightly smaller than the opening portion of the side surface portion 2b is provided below the side surface portion 2b. It is connected through an insulating spacer 42. Further, below the acceleration flange 44, the processing chamber chamber 5 is connected via an insulating spacer 43. With these connection structures, the ion source chamber 2, the acceleration flange 44, and the processing chamber chamber 5 can be set to different potentials while maintaining the airtightness inside.

A lead-out electrode support member 41 is attached to the accelerating flange 44 in contact with the peripheral edge portion thereof, and the lead-out electrode support member 41 and the accelerating flange 44 have the same potential. Then, the extraction electrode support member 41
The acceleration electrode 15 having a plurality of apertures 17 having a predetermined size and a predetermined size is attached in contact therewith, and has the same potential as the extraction electrode support member 41. A deceleration electrode 16 having a plurality of apertures 17 like the acceleration electrode 15 is attached to the electrode support member 41 via an insulating spacer 40 at a position below the acceleration electrode 15, and the acceleration electrode 15 and the deceleration electrode 16 are connected to each other. The extraction electrodes 3 are formed as a set to extract ions downward from the plasma generated in the ion source chamber 2. As the material of the extraction electrode 3, molybdenum having a high melting point and a small coefficient of thermal expansion is often used. Also,
It is desirable that the material of the support member 2 be the same as that of the extraction electrode 3 in order to make the thermal expansion to the same degree.

With the above-described structure, in the ion beam irradiation apparatus according to this embodiment, the back surface portion 2 of the ion source chamber 2 is maintained at the time of maintenance such as cleaning.
The support member 41 to which the extraction electrode 3 is attached can be attached to and detached from the acceleration flange 44 through an opening formed by separating a from the side surface portion 2b. As a result, the work of attaching the extraction electrode 3 to the support member 41 can be carried out separately at a desired location apart from the ion beam irradiation device.
It is easy to assemble the relative positions of 6 with high accuracy.

A gas supply device 8 is provided in the ion source chamber 2.
Is attached. A gas for ion implantation represented by phosphine or diborane is introduced into the ion source chamber by the gas supply device 8. A holder 23 for holding a substrate, which is a workpiece, is provided in the processing chamber chamber 5, and the substrate 23 is held by the holder 23.
Is held in the beam irradiation area by the beam irradiation device 31 so that ion implantation processing can be performed. Further, in the space between the extraction electrode 3 and the substrate 4 in the processing chamber chamber 5, a filament 26 as a neutralizer is provided.
Is provided so that the electric charge on the front surface of the substrate 4 during ion implantation can be neutralized.

The parts constituting the ion beam irradiation apparatus 31 not explained above have the same shape and dimensions as those of the ion beam irradiation apparatus according to the first embodiment shown in FIG. Although there are differences, the functions related to ion beam irradiation are the same, so description will be omitted.

The operation of the ion beam irradiation apparatus 31 according to the embodiment of the present invention will be described below. By supplying a large amount of electric power to the filament 18 as a heater, the filament 18 becomes hot and a large amount of heat is radiated. Since this radiant heat flows into the extraction electrode 3, the extraction electrode 3 can be rapidly heated. Therefore, the extraction electrode 3 can be brought into a thermally stable state when the temperature of the extraction electrode 3 is rapidly increased and the first substrate is processed. In this state, a gas for ion implantation represented by phosphine or diborane is introduced into the ion source chamber 2 by the gas supply device 8, arc plasma is generated, and ions are extracted from the plasma as an ion beam by the extraction electrode 3. By irradiating the substrate, stable ion implantation processing can be realized, and excessive ion implantation or insufficient ion implantation on the surface of the substrate 4 can be prevented.

7 and 8 show an ion milling device according to the third embodiment of the present invention. In the ion milling device according to the present embodiment, one of the differences from the devices according to the other embodiments described above is that the heater 18 also serves as the extraction electrode support member. The heater 18 has a ceramic electric heating element inside, and the same material as the extraction electrode 3 is used as the external material. The main heater 18 is attachable to and detachable from the acceleration flange 44. At the time of attachment, the heater 18 is connected to the atmosphere-side power source 1 via the contact terminal 51.
9 has a structure in which electric power is supplied. Therefore, like the ion beam irradiation apparatus according to the second embodiment described above, during maintenance such as cleaning, the extraction electrode 3 is removed from the opening formed by separating the back surface 2a of the ion source chamber 2 from the side surface 2b. The mounted heater 18 can be attached to and detached from the acceleration flange 44. As a result, the work of attaching the extraction electrode 3 to the support member 41 can be carried out separately at a desired location apart from the ion beam irradiation device, so that the relative positions of the acceleration electrode 15 and the deceleration electrode 16 constituting the extraction electrode 3 can be accurately determined. It is easy to assemble well.

The heater 1 also serving as the above-mentioned extraction electrode supporting member
8, the acceleration electrode 15 is attached in direct contact, and the deceleration electrode 16 is attached via an insulating spacer 40. The term "insulation" here means electrical insulation. In terms of heat, in order to heat the deceleration electrode 16 by transferring heat from the heater 18 by contact heat transfer, the material of the insulating spacer 40 is, for example, ceramics having high thermal conductivity such as alumina or aluminum nitride. Is preferably used.

Further, the ion milling device according to the present embodiment has a temperature sensor 45. The temperature sensor 4
5 has a temperature measuring unit on the vacuum side through the acceleration flange 44, and when the heater 18 also serving as the extraction electrode supporting member is attached to the acceleration flange 44, the temperature measuring unit is arranged so as to be pressed against the heater 18. It is set up. This allows the temperature sensor 4 to operate when the ion milling device operates.
5, the temperature of the heater 18 can be measured. The measured temperature of the heater is taken into the control device 28, and the temperature change thereof is collated and analyzed with the heater output and the data stored in advance, so that the temperature of the extraction electrode 3 can be estimated. . Further, the control device 28
Is the heater power supply 1 so that the extraction electrode 3 has a predetermined temperature.
It is possible to control 9 outputs. Instead of the extraction electrode temperature estimation means having the above structure, a temperature measurement means for directly contacting the extraction electrode 3 to measure the temperature of the extraction electrode 3 may be provided.

The operation of the ion milling device according to the embodiment of the present invention will be described below. By supplying the electric power to the heater 18, the temperature of the heater 18 becomes high. Since heat flows from the heater 18 having the high temperature into the peripheral portion of the extraction electrode 3 by contact heat transfer, the extraction electrode 3 can be rapidly heated. Therefore, the extraction electrode 3 can be brought into a thermally stable state when the temperature of the extraction electrode 3 is rapidly increased and the first substrate is processed. By irradiating the substrate 4 with the ion beam in this state, stable milling can be realized and overmilling or insufficient milling can be prevented.

Further, the heater 18 is provided by the temperature sensor 45.
Since the control device 28 can estimate the temperature of the extraction electrode 3 and control the output of the heater power supply 19, the extraction electrode 3 can be reliably heated to a desired temperature. It is possible to avoid excessive temperature rise.

Next, another operation of the present embodiment according to the present invention will be described. Therefore, first, thermal deformation of the extraction electrode during ion beam irradiation will be generally described.

In order to operate the ion beam irradiation device, it is necessary to generate plasma in the ion source chamber. With the generation of this plasma, heat inevitably flows from the plasma into the extraction electrode. Also,
Usually, heat also flows into the extraction electrode from the plasma generating means or the neutralizing means (neutralizer).

On the other hand, there are two factors that cause the heat to flow out from the extraction electrode, that is, due to radiation and due to contact heat transfer from the peripheral portion of the extraction electrode. It is considered that the temperature of the extraction electrode is stable when the amount of heat flowing in and the amount of heat flowing out are balanced, but unless special consideration is given, there is a heat path in which the heat entering from the center flows out from the peripheral part. In the extraction electrode, the temperature in the central portion becomes higher than that in the peripheral portion and becomes stable.

As described above, when the central portion of the extraction electrode has a higher temperature than the peripheral portion, a compressive thermal stress is generated in the surface of the extraction electrode, and in order to release this compression stress,
The extraction electrode is flexibly deformed in the direction perpendicular to the surface.
Therefore, the amount of flexural deformation of the extraction electrode is approximately proportional to the temperature difference between the central portion and the peripheral portion.

Hereinafter, the ion milling apparatus according to the third embodiment shown in FIGS. 7 and 8 will be described again. When the substrate 4 is irradiated with an ion beam by the ion milling apparatus to perform the milling process, the radiant heat from the filament 9 and the filament 26 flows into the extraction electrode 3.
Heat from the plasma generated in the ion chamber 2 due to arc discharge also flows into the acceleration electrode 15. Heat inflow is also generated in the deceleration electrode 16 due to collision of a part of the ion beam.

In a state where the heater 18 is not operated,
The heat flowing into the extraction electrode 3 is all that described above,
A part of these heat flows out to the heater 18 as the extraction electrode support member by contact heat transfer, directly to the acceleration electrode 15 and to the deceleration electrode 16 via the insulating spacer 40. Then, these heats continue to be generated by the heater 18
Through contact heat transfer to the acceleration flange 44, which is normally maintained at room temperature. The temperature distribution in the extraction electrode 3 when it is thermally stable in this state is shown in FIG. 9 in the case where the heater is not heated. At this time, the extraction electrode 3 has
Deflection in the vertical direction, which is approximately proportional to the temperature difference between the peripheral portion and the center, occurs.

Next, the heater 18 is operated to turn on the heater 18.
The case where the temperature of is raised will be described. In this case, the temperature of the extraction electrode 3 rises overall and the heat outflow due to radiation increases, while the rate of outflow from the peripheral portion to the heater 18 by contact heat transfer decreases, so that the peripheral portion of FIG. As in the temperature distribution shown as heating, the temperature difference between the peripheral portion and the center decreases in a thermally stable state. Therefore, the flexural deformation can be reduced as compared with the case where the heater is not heated.

Further, if the degree of heating of the heater is strengthened,
Since heat moves from the peripheral portion toward the center and becomes a heat flow emitted by radiation, the temperature of the peripheral portion is slightly higher than that of the central portion. The temperature distribution in the extraction electrode 3 at this time is shown in FIG. 9 for the case of strong heating of the peripheral portion. With this temperature distribution, a tensile stress acts in the extraction electrode 3, so that the flexural deformation does not occur.

As described above, by heating the peripheral portion of the extraction electrode during irradiation of the ion beam, the temperature difference between the center and the peripheral portion of the extraction electrode in a thermally stable state can be reduced.
Alternatively, they can be reversed, and the amount of flexural deformation of the extraction electrode can be reduced or eliminated. Thereby, the beam shape and the like in the ion beam irradiation can be controlled. Therefore, in the ion milling apparatus, it is possible to control the ion milling distribution in the substrate surface to a desired distribution shape.

The present invention is not limited to the above-mentioned embodiment, but the design can be changed appropriately. For example, the neutralizer can be configured by an electron gun (a hollow cathode type neutralizer, a plasma bridge type neutralizer, etc.) that irradiates a workpiece with an electron beam.

Further, the ion source can be constituted by a high frequency ion source or a microwave ion source.

The heater can also be attached to the deceleration electrode.

[0072]

According to the present invention, the velocity and distribution of the ion beam can be stabilized early after the apparatus is started. In the ion milling apparatus, the first several wafers after the apparatus is started or after the processing is restarted. It is possible to stabilize the milling process of the workpiece, and to improve the productivity.

If a heater is attached to the peripheral portion of the extraction electrode, the extraction electrode is heated by direct contact so that the extraction electrode can be quickly heated to a desired temperature (for example, 200 to 240).
The heater can be heated up to ° C), and the heater does not hinder the extraction of the ion beam from the aperture.

If the peripheral portion of the extraction electrode is heated during ion beam irradiation, the temperature difference between the center and peripheral portion of the extraction electrode in a thermally stable state can be reduced or reversed. Therefore, the amount of flexural deformation of the extraction electrode can be reduced or eliminated. This makes it possible to control the beam distribution and the like in ion beam irradiation.

Further, by curving the accelerating electrode and the decelerating electrode in the same direction in advance, it is possible to prevent the accelerating electrode and the decelerating electrode from being bent in different directions due to thermal expansion, and to prevent the irradiation of the ion beam from becoming unstable. .

[Brief description of drawings]

FIG. 1 is a simplified cross-sectional view of an ion milling device according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of an extraction electrode of the same device.

FIG. 3 is a front view of an acceleration electrode of the device.

FIG. 4 is a transition graph of a milling rate after grid heating in the same device.

FIG. 5 is a graph showing the relationship between the milling time, the grid temperature and the milling rate in the conventional device.

FIG. 6 is a simplified sectional view of an ion beam irradiation apparatus according to a second embodiment of the present invention.

FIG. 7 is a simplified cross-sectional view of an ion milling device according to a third embodiment of the present invention.

FIG. 8 is an enlarged cross-sectional view of an extraction electrode heater of an ion milling device according to a third embodiment of the present invention.

FIG. 9 is a graph showing a temperature distribution in the surface of the extraction electrode when the extraction electrode of the ion milling device according to the third embodiment of the present invention is heated.

[Explanation of symbols]

1 ion milling equipment 2 Ion source chamber 3 Extraction electrode 15 Accelerating electrode 16 Deceleration electrode 17 Aperture 18 heater 28 Control device 31 Ion beam irradiation device 45 Temperature sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Satoshi Ichimura Satoshi Ichimura 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Electric Power & Electric Development Division (72) Inventor Keitaro Oishi Kokubun, Hitachi City, Ibaraki Prefecture 1-1-1, Machi, Ltd., Kokubun Plant, Hitachi, Ltd. (72) Inventor, Masamichi Moriyama 2--15, Egawa, Shimamoto-cho, Mishima-gun, Osaka (15) Readlight SMI Co., Ltd. (56) References 57-163950 (JP, A) JP-A-6-119896 (JP, A) JP-A-8-8230 (JP, A) JP-A-10-188869 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) H01J 27/02 H01J 37/08 H01J 37/30 H01J 37/305

Claims (12)

(57) [Claims] 1. In an ion milling apparatus equipped with an extraction electrode for extracting ions in plasma generated in an ion source chamber as an ion beam, the extraction electrode is plate-shaped, and a peripheral portion of the extraction electrode is heated.
However, the temperature difference between the periphery and the center is reduced or reversed.
An ion milling device, which is provided with a heater for heating. 2. A plastic generated in an ion source chamber
Extraction electrode for extracting ions in the Zuma as an ion beam
In the ion milling device provided with, a heater for heating the extraction electrode is provided, the extraction electrode is a plate shape provided with a large number of apertures, and the heater is
Characterized by heating the peripheral portion of the extraction electrode
That ion milling apparatus. 3. The ion milling device according to claim 1, wherein the extraction electrode includes an acceleration electrode and a deceleration electrode, and the acceleration electrode and the deceleration electrode are curved in the same direction. 4. A plastic generated in an ion source chamber
Extraction electrode for extracting ions in the Zuma as an ion beam
An ion milling device comprising: a heater for heating the extraction electrode, and means for measuring or estimating the temperature of the extraction electrode, and controlling the heater output according to the temperature of the extraction electrode. . 5. In an ion milling apparatus for extracting ions in an ion source chamber as an ion beam by an extraction electrode and irradiating the surface of a workpiece with the ion beam, the extraction electrode is heated before performing ion milling. An ion milling method characterized by the above. 6. In an ion milling method of extracting ions in an ion source chamber as an ion beam by an extraction electrode and irradiating the surface of a workpiece with the ion beam, the extraction electrode is plate-shaped, The peripheral part of the extraction electrode is heated, and the peripheral part and the peripheral part and the central part are heated.
An ion milling method characterized by reducing or reversing the degree difference . 7. An ion beam irradiation apparatus comprising an extraction electrode for extracting ions in a plasma generated in an ion source chamber as an ion beam , wherein the extraction electrode is plate-shaped, and the extraction electrode is heated to a peripheral portion.
An ion beam irradiation apparatus comprising a heater for reducing or reversing the temperature difference between the center and the central part . 8. A plastic generated in an ion source chamber
Extraction electrode for extracting ions in the Zuma as an ion beam
In the ion beam irradiation apparatus including, the extraction electrode is a plate shape provided with a large number of apertures,
By heating the peripheral portion of the extraction electrode, the temperature of the peripheral portion and the center portion
An ion beam irradiation device, characterized in that a heater for reducing or reversing the degree difference is provided. 9. The ion beam irradiation apparatus according to claim 7, wherein the extraction electrode includes an acceleration electrode and a deceleration electrode, and the acceleration electrode and the deceleration electrode are curved in the same direction. . 10. A probe generated in the ion source chamber.
Extraction power to extract ions in plasma as an ion beam
In an ion beam irradiation device equipped with a pole,
An ion beam irradiation apparatus comprising a heater for heating a pole and a means for measuring or estimating the temperature of the extraction electrode, and controlling the heater output according to the temperature of the extraction electrode. 11. An ion beam irradiation method of extracting ions in an ion source chamber as an ion beam by an extraction electrode and irradiating the surface of a workpiece with the ion beam, wherein the extraction electrode is irradiated before the ion beam irradiation. An ion beam irradiation method characterized by heating. 12. An ion beam irradiation method for extracting ions in an ion source chamber as an ion beam by an extraction electrode and irradiating the surface of a workpiece with the ion beam, wherein the extraction electrode is plate-shaped and at the time of ion beam irradiation. , Heating the peripheral portion of the extraction electrode to reduce the temperature difference between the peripheral portion and the central portion.
An ion beam irradiation method characterized by reducing or reversing .