JPS61206143A - Fusing method for ionized material in liquid metal ion source - Google Patents

Abstract

PURPOSE:To improve the heating efficiency while to simplify the structure by irradiating laser beam onto a needle electrode thus thermally fusing the ionized material. CONSTITUTION:The laser beam 8a produced from a laser oscillator 8 is reflected by two adjusting mirrors 9, 10 then collected through collection lens 11 and led through a window glass 12 into a vacuum container 7 thus to form a spot 14 at the tip of an ion discharging needle 2 and to heat it. Since the tip section of ion discharging needle 2 can be directly heated locally, the heating efficiency can be improved. While since the heating source is not arranged in a vacuum container, the structure is simplified.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for melting an ionized substance in a liquid metal ion source, and particularly to a method for melting an ionized substance in a liquid metal ion source that heats and melts the ionized substance using a laser beam. .

[Background of the invention]

Conventional methods for melting ionized substances in liquid metal ion sources mainly use electrical heating means. For example, as shown in FIG. 9, when the ion emitting needle 2 is supported by a plurality of support parts 3, the support parts 3 are electrically heated to melt the ionized substance 1 adhering to the surface thereof. ing. However, in this case, the ionic substance 1 cannot be stored in a large capacity. Further, when a large current is passed through the support part 3 to melt an ionized substance having a high melting point, the support part 3 may be damaged. Next, Figure 10 shows Instow, Fiz, Conf, Cell, &54, published in 1980:
Chabuta-7 (Inst, Phyg, Conf.

S sr, NQ54: Chapter 7)
Liquid Metal Field Emission Ion Source Ion Source Is and There Applications as described on pages 316 to 321;
Metalfield emission io
n 5 sources and theirapp
lications; P, D, P rew
ett and D, K.

In this case, the reservoir part has a cylindrical shape, the bottom surface 4a of which is inclined downwardly toward the center, and a through hole 4b is formed in the center part. 4 is provided, and an ion emitting needle 2 is inserted into the central part of the reservoir 4 and projects downward with its lower end penetrating the through hole 4b; An ionized substance 1 is stored between the wall and the wall. Further, a cylinder 6 made of an insulating material is fixed to the outer periphery of the reservoir 4, and a heater 5 is fixed to the outer peripheral surface of the cylinder 6. Therefore, in the above configuration,
By heating the heater 5, the ionized substance 1 in the reservoir 4 is melted through the cylinder 6. However, in the above configuration, when using the ionized substance 1 with a high melting point, it is necessary to supply a large current to the heater 5, and the ionized substance 1 needs to be supplied with a large current.
This includes problems such as a decrease in heating efficiency. As described above, in the conventional electrical heating method, when an ionized substance with a high melting point is used, a large current is required, and thus an electric wire is required for passing the large current. Generally, in an ion beam device, the ion source part is several K due to its configuration.
Since the electric wire needs to be floated at a high voltage of V or more and placed in a high vacuum container, increasing the capacity of the electric wire will complicate the structure. Further, when a reservoir 4 for storing the ionized substance 1 is provided as shown in FIG. 10, there are problems such as a decrease in heating efficiency.

[Purpose of the invention]

The present invention solves the above-mentioned conventional problems, extends the life of the ion source, improves the heating efficiency of the ion source, and simplifies the configuration when introducing a large current into the vacuum high potential section. An object of the present invention is to provide a method for melting an ionized substance in a liquid metal ion source.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention is characterized in that an ionized substance is heated and melted using a laser beam, and in particular, a laser beam is directly sourced into a vacuum container to heat and melt the ionized substance. Alternatively, the method is characterized in that the ion emitting needle and the reservoir section are directly irradiated with a laser beam to heat them.

[Embodiments of the invention]

1 to 6 showing embodiments of the present invention will be described below. FIG. 1 is an explanatory front view of an ion emitting needle heating device showing an embodiment of the present invention, FIG. 2 is an explanatory front view of an ion emitting needle and a reservoir heating device,
Fig. 3 is an explanatory front view of the ionized substance heating device, Fig. 4 is an explanatory plan view showing an example of the ion emission needle and ionized substance simultaneous heating device, and Fig. 5 is the ion emission needle and ionized substance simultaneous heating. FIG. 6(a) is an explanatory plan view showing another example of the device, and FIG. 6(b) is an explanatory front view showing another example of the ion emitting needle heating device.
t*-A plan view taken along the line A-A', FIG. 7 is an explanatory front view showing another example of the ion-emitting needle and the ionized substance heating device, and FIG. 8 is the ion-emitting needle shown in FIG. 7. FIG. 2 is an explanatory front view showing an ion beam output control device for an ionized substance heating device. In Figure 1, 7
is a vacuum container, and inside is an ionized substance such as Ga.
A reservoir part 4 for holding an ion emitting needle 2 made of tungsten or the like is held in the center thereof, and a window 7a is formed in a part of the side wall.
A is sealed with a window glass 12.

A laser oscillator 8 is formed of, for example, a YAG laser and outputs a laser beam 8a. 9,
10 is two adjustment mirrors, 11 is a condensing lens, 13 is a condensed beam, and 14 is a condensed spot where the condensed beam 13 is formed at the tip of the ion emitting needle 7. The two adjustment mirrors 9° 10 are movable in the directions of the up and down arrows, and the condenser lens 11 is movable in the directions of the up and down arrows and the left and right arrows.
The position is adjustable. Because of the above configuration,
A laser beam 8a output from a laser transmitter 8 is reflected by two adjustment mirrors 9 and 10, and then reflected by a condenser lens 1.
1, the focused beam 13 is introduced into the vacuum chamber 7 through the window glass 12, and forms a focused spot 14 at the tip of the ion emitting needle 2. The area is heated by irradiation. Therefore, in this embodiment, the tip of the ion-emitting needle 2 can be locally and directly heated, so that heating efficiency can be improved. Furthermore, since the heating source is not installed inside the vacuum container as in the conventional case, the structure is simple.

Next, in FIG. 2, as is clear from the comparison with FIG. 1, there are three adjusting mirrors 9, 10a.

10b and two condensing lenses lla and llb are provided,
A laser beam 8a from a laser transmitter 8 is divided into two by three adjustment mirrors 9, 10a, and 10b, and each laser beam 8a is focused by two condensing lenses lla and llb, respectively. The focused beams 13a and 13b are introduced into the vacuum container 7 through the window glass 12, and focused spots 14a and 14b are simultaneously formed on the tip of the ion emitting needle 2 and the reservoir section 4, so that the ion emitting needle 2
and the reservoir section 4 are heated at the same time.

Therefore, in this embodiment, as compared with the embodiment shown in FIG. 1, the ionized substance 1 can be heated in addition to the ion emitting needle 2 at the same time, so that the ionized substance 1 can be heated in a short time.

This allows application to the ionized substance 1 having a high melting point.

Next, in FIG. 3, two condensing lenses 11a,
Two condensed beams 13a condensed by Ilb.

13b is introduced into the vacuum container 7 through the window glass 12. In this embodiment, the reservoir section 4 is made of a material that allows the laser beam 8a to be seen through, such as heat-resistant quartz glass, so that the two focused beams 13a can be seen through the reservoir section 4.
, 13b is a light spot 14c that passes through the reservoir section 4 and is directly focused on the ionized substance 1 therein.

14d can be formed and heated. Therefore, in this embodiment, the heating efficiency can be further improved and the heating time can be shortened.

Next, FIG. 4 shows a case where an ionized substance transparent to the laser beam is used. In this case, a CO2 laser 8b is used as the laser beam, and the adjustment mirrors 9, 10a, 10b in FIG. 3 are used. and condensing lens l
In place of la and llb, two lenses 15.16 made of Ge, Cd-Te, ZeSs, etc. that are transparent to the wavelength of the Co2 laser 8b are provided, and the same as the two lenses 15.16 described above. The lens 1 is formed of a transparent material.
Reflection part 18a formed in an arc shape with an opening on the 5.16 side
The lens 1 is fixed to the inner circumferential surface of the reflecting portion 18a.
6 parallel laser beams 17a.

17b...17g to reflect the light and focus it on the ion emitting needle 19 inserted therein, a reflective film 18b formed of a reflective material such as a gold vapor deposited film;
A reservoir section 18 is provided, which includes a flat transparent section 18c fixed to the opening of the reflecting section 18a. Note that the two lenses 15 and 16 have parallel light beams 17a, .
... A device for obtaining 17 g, that is, a collimator (Colim
atar). The ionized substance 20 in the reservoir section 18 is made of a material transparent to the Co2 laser 8b, such as Si, GaAs, or the like. With the above configuration, the cog laser 8b from the laser oscillator 8 is converted into a parallel laser beam 17. by the two lenses 15.16. a...17g, passes straight through the window glass 12 and the transparent part 18c, and passes through the reflective film 18b.
The light is reflected by the ion-emitting needle 19 and is focused on the ion-emitting needle 19 to heat it. Therefore, in this example, C○2
Before the laser beam 8b reaches the ion emitting needle 19, it can partially absorb and heat the ionized substance 20 surrounding it.

Next, in FIG. 5, parallel laser beams 17a, . . . , 17g from the lens 16 are transmitted between one of the lenses 16 shown in FIG. A condensing lens 22 is provided to condense the light to a focal point 21 between the condensed light 18c and guide it to the reflective film 18b of the reservoir section 18. Further, the reflecting part 18a and the reflecting film 18b of the reservoir part 18 are formed in an elliptical cylindrical shape so that the Co2 laser beam guided from the focal point 21 to the reflecting film 18b is reflected and focused on the ion emitting needle 19. ing. With the above configuration, the CQ2 laser 8b from the laser oscillator 8 has two lenses 15.1.
6, the parallel laser beams 17a...17g are turned into parallel laser beams 17a...17g, which are then focused by a condenser lens 22 through the window glass 12 onto a focal point 21 in the ionized substance 20 inside the vacuum container 4. The light is guided into the reservoir section 18, reflected by the reflective film 18b, and focused on the ion emitting needle 19 to heat it. Therefore, in this embodiment, the ion emitting needle 19
And the ionized substance 20 can be heated uniformly.

Next, in FIGS. 6(a) and 6(b), the tip of the ion emitting needle 2 is heated in the same manner as shown in FIG. 4. In this case, a parabolic mirror 23 for reflection is provided around the tip of the ion emitting needle 2 below the reservoir section 4. In this case, the laser beam used may be opaque to the ionized substance 1. With the above configuration, the laser beam 8b from the laser transmitter 8 shown in FIG.
7e, which passes straight through the window glass 12, is reflected by the parabolic mirror 23, and is focused on the ion emission needle 2 to heat it. Although this embodiment has been described using a method similar to that shown in FIG. 4, the present invention is not limited to this, and it is also possible to use a method similar to that shown in FIG. 5.

Next, FIG. 7 shows another example of heating the tip of the ion emitting needle.
A flange 4 is fixed to the upper part of a vacuum container (not shown), and a glass window 26 is fixed to the center part through an O-ring 25. 27 is a plurality of insulators,
A high voltage terminal 28 connected to a power source (not shown) is fastened to the upper part, and an electric wire (not shown) is inserted inside. Reference numeral 29 is a plurality of upper support parts, the upper end of which is fixed to the flange 24, the lower end of which is fixed with a fixing plate 30, into which the electric wire from inside the insulator 27 is inserted. Reference numeral 31 denotes a glass plate forming a concave lens, which is fixed to the center of the fixed plate 30. 32 is a cylindrical lower support part whose upper end is fixed to the fixing plate 30, whose lower end is bent inward and has a bottomless bowl-shaped mirror 33 fixed to its upper surface. A reservoir section 34 is supported within the lower support section 32, and an ion emitting needle 36 is supported therein via an ionized substance 35 so that its lower end protrudes to the outside. A mirror 37 reflects a laser beam 38 from a laser source (not shown) toward the window 26 below. Although electric wires inserted into the upper support part 29 and the lower support part 32 are not shown, they are connected to the ionized substance 35 to introduce voltage from a power source into the ion source 35. With the above configuration, when the parallel laser beam 38 reflected by the mirror 37 passes through the window 26 and is introduced into the vacuum container,
The laser beam 38 at the center is dispersed by the glass plate 31.
enters the ionized substance 35 inside the reservoir section 34 from above and heats the ionized substance 35 and the ion ejection needle 36. Further, the laser beam 38 dispersed around the outer periphery of the reservoir section 34 is reflected by the mirror 33 and irradiates the periphery of the tip of the ion emitting needle 36 to heat it. Therefore, in this embodiment, the reservoir part 34, the laser introduction part to the ionized substance 35 and the ion emission needle 36, and the optical system for introducing the laser to this laser introduction part are integrally formed. If adjustments are made between the installation special numbers, there will be no need to do so from now on, making the operation easier.

Next, FIG. 8 shows a laser control device using a laser-based ionized substance and an ion emitting needle heating device shown in FIG. As shown in FIG.
9, fixed plate 30, glass 31. Lower support part 32, mirror 33, reservoir 34. An ion source 40 consisting of an ionizing substance 35 and an ion emitting needle 36, a plate-shaped extraction electrode 41a and an aperture 41b arranged below the ion source 40 at intervals in the vertical direction; a connector 44a that seals conductive wires 43a and 43b for connecting the thermocouple 55 supported by the ion emission needle 36 of the ion source to the external beam current control system 42, respectively;
44b. Reference numeral 45 designates a laser oscillator, which outputs a laser beam 47 whose output is controlled to a constant level by a power supply controller 46 toward a beam expander 48 consisting of two convex lenses. This beam expander 48 adjusts the diameter of the laser beam 47. Reference numeral 49 is a variable transmittance filter, which is formed by depositing a disk-shaped metal thin film using transparent glass while continuously changing its density, and the outer periphery of the filter is coated from the expander 48 as shown in FIG. 7 above. The laser beam 50 is inserted into the laser beam 50 flowing toward the mirror 37 shown in FIG. 3 to adjust the amount of transmitted light of the laser beam 50. Reference numeral 51 is a filter driving motor, and a gear 52b that meshes with a binion 52a fixed coaxially with the variable transmittance filter 49 is fixedly supported at the end of the shaft. A detector 53 receives about 1% of the laser beam that has passed through the mirror 37 and transmits a monitor signal corresponding to the laser power of this laser beam to the beam current control system 42. The beam current control system 42 receives the monitor signal from the detector 53, the beam current from the aperture 41b, and the temperature from the thermocouple 55 of the ion ejection needle 36, and
When the temperature changes, the information is sent to the motor control circuit 54. This motor control circuit 54 rotates the filter drive motor 51 in conjunction with the signal from the beam current control system 42, rotates the variable transmittance filter 49, and directs the laser beam 50 from the beam expander 48 to the mirror 37. It's like adjusting the amount of light. In addition, 56 shown in the figure is an ion beam that enters the aperture 41b from the ion emission needle 36 through the extraction electrode 41a, and 57 is an ion beam near the center that passes between the ion emission needle 36 and the aperture 41b. Used for exposure, implantation, etc. With the above configuration, when the laser beam 47 with a constant output is output from the laser transmitter 45 toward the beam expander 48, the laser beam 50 whose diameter is adjusted by the beam expander 48 is reflected by the mirror 37. , and are introduced into the vacuum vessel 39 through the window 26. Next, the laser beam 50 is dispersed while passing through the glass plate 31, and is dispersed into the ionized substance 3 in the reservoir section 34 provided in the ion source 39.
5 to heat the ionized substance 35 and the ion emitting needle 36. Further, the laser beam dispersed around the outer periphery of the reservoir section 34 is reflected by the mirror 33 to heat the periphery of the tip of the ion emitting needle 36. Next, the laser beam irradiated around the tip of the ion emitting needle 36 is caused by the extraction electrode 41a to cause the surrounding laser beam 56 to enter the aperture 41b, and at the same time, the central laser beam 57 passes between the apertures 41b for processing. Used for exposure, implantation, etc. The beam current sent from the aperture 41b to the beam current control system 42 or the thermocouple 55 of the ion emitting needle 36
When the temperature sent to the beam current control system 42 changes, the beam current control system 42 detects this and sends a signal to the motor control circuit 54, and the signal from the motor control circuit 54 controls the filter driving motor 51. is driven, the variable transmittance filter 49 rotates and adjusts the amount of transmitted light of the laser beam 50 flowing from the expander 48 toward the mirror 37. Therefore, in this embodiment, the beam current from the ion ejection needle 36, the output of the laser irradiating the ionized substance 35 and the ion ejection needle 36, and the temperature inside the reservoir section 34 are monitored to keep the laser output constant. be able to.

〔Effect of the invention〕

As described above, the present invention provides a reservoir capable of holding a sufficient amount of ionized material, can efficiently heat this ionized material, and introduces a large current into the ion source section which is in a vacuum and has a high potential. As a result, the laser heating device can be configured simply, and the laser output can be maintained constant by monitoring the temperature of the reservoir and the amount of ion current output from the ion ejection needle. It has the effect of

[Brief explanation of drawings]

Fig. 1 is an explanatory front view of an ion emitting needle heating device showing an embodiment of the present invention, Fig. 2 is an explanatory front view of an ion emitting needle and reservoir heating device, and Fig. 3 is an ionized substance heating device. An explanatory front view of the device, FIG. 4 is an explanatory plan view showing an example of an ion emitting needle and an ionized substance simultaneous heating device, and FIG. 5 is an explanatory plan view showing another example of an ion emitting needle and an ionized substance simultaneous heating device. 6(a) is an explanatory front view showing another example of an ion emitting needle tip heating device; FIG. 6(b) is a sectional plan view taken along line A-A'; FIG. 7 is an explanatory front view showing another example of the ion emitting needle and ionized material heating device, and FIG. 8 is an explanatory front view showing the ion emitting needle and ion beam output control device for the ionized material heating device shown in FIG. 7. FIG. 9 is an explanatory diagram showing an example of an ionized substance heating device for a conventional liquid metal ion source.
FIG. 0 is an explanatory diagram showing another example of the prior art. 1, 20.35...Ionized substance, 2.19.3
6... Ion release needle, 3... Support part, 4...
... Reservoir, 5... Heater, 6... Cylinder, 7, 3
9...Vacuum container, 8°45...Laser transmitter, 9
, 10.23.33.37... Mirror, 11... Condenser lens, 13... Condensed beam, 14... Condensed spot, 15.16... Lens, 17... Parallel Laser beam, 113, 34... Reservoir part, 21...
Focus, 24...flange. 25...0 ring, 26...window, 27...insulator, 28...high voltage terminal, 29...upper support part, 30
... Fixed plate, 31... Glass plate, 32... Lower support part, 38.47.50... Laser beam. 40... Ion source, 41a... Extraction electrode, 41
b...Aperture, 42...Beam current control system, 4
3... Conductor wire, 44... Connector, 46... Power controller section, 48... Beam expander, 49...
... Transmittance variable filter, 51... Filter drive motor, 53... Detector, 54... Motor control circuit, 55... Thermocouple, 56.57... Ion beam. Representative Patent Attorney Tadashi Akimoto Figure 1 Figure 2 Figure 3 Figure 4 A Tree Figure 6 (G) (b) Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] 1. A needle-shaped electrode and an ionized substance are housed in a reservoir supported in a vacuum chamber, and the needle-shaped electrode is heated and melted, and a high voltage is applied to release the molten substance or ions from its tip. A method for melting an ionized substance in a liquid metal ion source that extracts a beam, the method comprising heating and melting the acicular electrode by irradiating the needle-like electrode with a laser. 2. A liquid metal ion source that stores a needle-shaped electrode and an ionized substance in a reservoir supported in a vacuum chamber, heats and melts the needle-shaped electrode, and applies a high voltage to extract the molten substance or ion beam from its tip. A method for melting an ionized substance in a liquid metal ion source, characterized in that the ionized substance is irradiated with a laser to heat and melt the ionized substance, thereby heating and melting the needle-shaped electrode. 3. A needle-shaped electrode and an ionized substance are housed in a reservoir supported in a vacuum chamber, and the needle-shaped electrode is heated and melted, and a high voltage is applied to draw out the molten substance or ion beam from the tip of the liquid metal ion. A method for melting an ionized substance in a liquid metal ion source, characterized in that the reservoir is irradiated with a laser and heated to heat the ionized substance and the needle-like electrode inside the reservoir. 4. A method for melting an ionized substance in a liquid metal ion source according to claim 1, 2, or 3, wherein the laser is output from a laser oscillator provided outside the vacuum chamber. 5. A method for melting an ionized substance in a liquid metal ion source according to claim 1, 2, 3, or 4, wherein the laser is focused.