KR20030085198A - Apparatus and method for supplying cesium - Google Patents

Abstract

The present invention relates to a cesium supply device and method suitable for increasing the evaporation efficiency of cesium and stably supply for a long time, the gas flow control unit for controlling the amount of inert gas injected from the outside, and the injection from the gas flow control unit A preheater for preheating the inert gas, a cesium reservoir for discharging cesium by pressure gas, an injector for receiving and injecting cesium from the cesium reservoir, and vaporizing cesium injected from the injector, and the preheater And a cesium vaporization unit for discharging cesium gas together with the inert gas injected therefrom.

Description

Cesium Feeder and Method {APPARATUS AND METHOD FOR SUPPLYING CESIUM}

The present invention relates to a cesium supply device and method, and more particularly, to a cesium supply device and method that can increase the gasification efficiency of cesium (Cesium: Cs), and can continuously supply cesium gas for a long time.

In general, ion sources are used for ion implantation, sputter deposition, ion beam deposition, ion spectroscopy, and the like.

In particular, cesium ions serve to lower the work function of the surface when a sufficient amount is present on the surface of the substrate to be treated. This is because cesium has a very low electron affinity.

Thus, cesium increases the electron emission at the substrate surface.

Meanwhile, cesium is known to have a liquid point and a boiling point of 28 ° C and 690 ° C under atmospheric pressure, respectively, and a vapor pressure of 10E-4 Torr at 100 ° C.

However, since cesium is easily oxidized by oxygen and is poor in controlling the vapor pressure of cesium due to the poor property of exploding upon contact with moisture, there are many limitations in using cesium ions.

Hereinafter, a cesium supply apparatus according to the prior art will be described with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a cesium supply apparatus using a conventional cesium solid electrolyte disclosed in US Patent No. 5,521,389.

As shown in FIG. 1, a cesium supply device using a cesium solid electrolyte in the related art is provided with an ion pellet 11 containing an oxide cesium compound and a metal contact from the cesium compound in the ion pellet 11. And a heater 13 for applying heat to the ion pellet 11 so that cesium ions are discharged through the ion generator 12.

In addition, a heat shielding film (not shown) formed outside the heater 13 using molybdenum or tantalum to prevent heat generated from the heater 13 from being radiated to the outside, and An anode electrode (not shown) for electrical connection of the ion pellet 11 and a metal tube (not shown) for preventing the cesium compound outflow from the ion pellet 11 are further included.

Here, the ion generator 12 is a porous electrode formed by coating tungsten on one surface of the ion pellet 11, and the heater 13 formed around the ion pellet 11 is It consists of filaments coated with aluminum.

In the conventional cesium supply apparatus using the cesium solid electrolyte as described above, the solid electrolyte containing cesium generates cesium ions at a high temperature of 900 to 1000 ° C.

In addition, since the amount of the solid electrolyte encapsulated in the ion pellet 11 is limited, it is impossible to use it for a long time, and since the spray area of the ion beam is limited, the deposition process in a wide area is difficult.

When the ion pellet 11 is used for a long time in an oxidizing atmosphere, an oxide film is formed in the porous ion generating unit 12 by the oxidation of cesium, so that the amount of cesium ions is unstable.

Therefore, a device capable of controlling the heating of the ion pellet 11 by measuring the injection amount in order to accurately control the injection amount of cesium ions is required, and the cesium supply device is used in a physical vapor deposition (PVD) process. In use, the spray area cannot be controlled because cesium ions generated by heating to a high temperature spread only by thermal gas movement in a vacuum.

FIG. 2 is a schematic view showing another cesium supply device using a conventional exothermic ribbon disclosed in US Pat. No. 5,466,941, to improve the problem of the cesium supply device using the cesium solid electrolyte.

As shown in FIG. 2, the cesium supply apparatus using the exothermic ribbon includes a pair of extraction electrodes 21 for extracting and injecting cesium, and an exothermic ribbon 22 for ionizing cesium injected from the extraction electrode 21. And beam forming electrodes (not shown) disposed above and below the exothermic ribbon 22 to form cesium cations ionized by the exothermic ribbon 22 in a beam form.

Here, a heater (not shown) for controlling a vapor pressure for injecting cesium not ionized into the exothermic ribbon 22 is configured in the extraction electrode 21, and the exothermic ribbon 22 is tungsten. Is formed.

However, the cesium supply apparatus using the exothermic ribbon configured as described above needs to heat the extraction electrode 21 to a high temperature of 300 to 400 ° C. in order to inject the cesium that is not ionized, and the cesium injected from the extraction electrode 21. The exothermic ribbon 22 should be heated to a high temperature of 1200 ° C. in order to cationic.

The present invention is to solve the problems of the conventional cesium supply device and method, it is an object of the present invention to provide a cesium supply device and method that can supply a large amount of cesium gas by increasing the vaporization efficiency of cesium.

Another object of the present invention is to provide a cesium supply apparatus and method which can stably supply for a long time by preventing oxidation and deterioration of cesium.

It is still another object of the present invention to provide a cesium supply apparatus and method capable of finely controlling the amount of cesium gas supplied.

1 is a block diagram showing a cesium supply apparatus using a conventional cesium solid electrolyte (solid electrolyte)

2 is a block diagram showing a cesium supply device using a conventional heating ribbon

Figure 3 is a block diagram showing a cesium supply apparatus according to the present invention

Explanation of symbols for the main parts of the drawings

31: gas flow control unit 32: the first flow pipe

33: second flow tube 34: preheating unit

35: pressure gas supply pipe 36: cesium storage unit

37: injector 38: third flow tube

39: cesium vaporization unit 40: heater

41: first valve 42: second valve

43: vapor deposition apparatus 44: tube

The cesium supply apparatus according to the present invention for achieving the above object is a gas flow control unit for adjusting the amount of inert gas injected from the outside, and preheating the inert gas injected through the first flow pipe from the gas flow control unit The preheating unit, a cesium storage unit for discharging cesium by the pressure gas supplied through the pressure gas supply pipe, an injector for receiving and injecting cesium from the cesium storage unit, vaporize the cesium injected from the injector, the preheating And a cesium vaporization portion for discharging the cesium gas through the third flow tube together with the inert gas injected from the second flow tube.

Here, the injector periodically injects cesium in the liquid state by the pulse signal applied from the outside, and adjusts the particle size, amount, and degree of spread of the cesium being injected.

The cesium supplying method according to the present invention comprises a first step of controlling the amount of inert gas injected from the outside, a second step of preheating the inert gas, and a step of vaporizing the cesium supplied by the pressure gas and then vaporizing And a fourth step of discharging the vaporized cesium together with the preheated inert gas.

Hereinafter, a cesium supply apparatus according to the present invention will be described with reference to the accompanying drawings.

Figure 3 is a block diagram showing a cesium supply apparatus according to the present invention.

As shown in FIG. 3, the cesium supply device according to the present invention includes a gas flow controller (MFC) 31 for controlling the amount of inert gas injected from the outside, and the gas flow controller 31. Cesium by the preheater 34 preheating the inert gas injected through the first flow pipe 32 through the second flow pipe 33 and the pressure gas supplied through the pressure gas supply pipe 35. After discharging the cesium storage unit 36, the injector (37) for receiving and injecting cesium from the cesium storage unit 36, and the cesium injected from the injector 37, the preheating unit The cesium vaporization part 39 which discharges cesium gas through the 3rd flow pipe 38 with the inert gas injected from the 34 through the 2nd flow pipe 33 is contained.

In addition, a heater 40 for heating the preheater 34, the cesium reservoir 36, and the cesium vaporizer 39, respectively, and the first, second, and third flow tubes 32, 33, and 38 are heated. A first valve 41 installed in the second flow pipe 33 for supplying / blocking a heating wire installed around the inlet gas and the inert gas injected from the preheater 34 to the cesium vaporizer 39. And a second valve 42 installed in the third flow pipe 38 to supply / block cesium gas from the cesium vaporizer 39 to the deposition apparatus 43, and to the cesium reservoir 36. It further includes a pressure gas regulator (not shown) installed in the pressure gas supply pipe 35 to adjust the amount of pressure gas injected.

Here, a pressure gas regulator uses a two stage pressure regulator, and the cesium reservoir 36 and the injector 37 are connected through a tube 44. Similar to the flow tubes 32, 33, and 38, a heating wire may be formed around the 44.

The inert gas may use not only argon (Ar) gas but also nitrogen (N ₂ ) gas or helium (He) gas, and an inert gas may be used as the pressure gas supplied to the cesium storage unit 36. _{Use 2}

The cesium reservoir 36 is filled with liquid cesium, and in order to maintain the cesium in the liquid state, the temperature of the cesium reservoir 36 must be maintained at 27 ° C. or higher.

In addition, the injector 37 is controlled by a pulse signal applied from an external control device, and injects cesium in a liquid state periodically by repeating an operation of opening and closing the injection port of the injector 37.

In addition to the physical vapor deposition apparatus, the cesium supply apparatus supplies cesium gas to a vapor deposition apparatus, a chemical vapor deposition apparatus using an ion beam, an electron tube or a camera tube of a display device, an electron microscope, a photoelectric generator, and the like.

Referring to the operation of the cesium supply apparatus according to the present invention having the configuration as described above are as follows.

First, the amount of inert gas injected from the outside is controlled by the gas flow control unit 31, and the inert gas injected into the preheater 34 through the first flow pipe 32 is formed in the preheater 34. It is preheated by the heater 40 provided in the circumference.

Then, a pressure gas is supplied to the cesium storage unit 36 filled with cesium in the liquid state. At this time, the pressure gas supplied through the pressure gas supply pipe 35 discharges cesium in the cesium storage unit 36 to the outside. That is, as the pressure gas is injected, the pressure in the cesium reservoir 36 is increased, so that the cesium is sent to the injector 37 through the pipe 44.

Here, the amount of cesium sent from the cesium storage unit 36 to the injector 37 depends on the amount of pressure gas, and the amount of pressure gas is controlled by the pressure gas regulator.

The injector 37 supplied with cesium from the cesium storage unit 36 periodically injects cesium into the cesium vaporization unit 39 according to a pulse signal applied from the outside. At this time, the particle size, amount, and degree of spread of cesium to be injected depend on the shape and size of the injection hole of the injector 37.

Subsequently, the cesium sprayed with the fine particles is vaporized by instantaneous heating when it touches the inner surface of the heated cesium vaporization unit 39, and the pressure inside the cesium vaporization unit 39 is also instantaneously by the momentarily vaporized cesium. Will increase. At this time, the smaller the particle size of the injected liquid cesium, the wider the spreading degree and the more uniform, the higher the vaporization rate.

Subsequently, the vaporized cesium is discharged through the third flow tube 38 together with the preheated inert gas injected from the preheater 34 and finally injected into the deposition apparatus 43.

Here, the cesium vaporization unit 39 is heated to a temperature of 200 ~ 300 ℃ by the heater 40 to vaporize cesium, the first, second, third flow pipes (32, 33, 38) are the same by the hot wire Maintained at temperature. In addition, the entire cesium supply apparatus except for the gas flow control unit 31 and the third gas flow pipe 38 may be charged into a heating oven and uniformly controlled at the same temperature.

Since the cesium supply device adjusts the amount of cesium supplied to the injector 37 by using a pressure gas control device, the amount of cesium gas supplied to the deposition apparatus 43 can be precisely controlled. In addition, since the fine liquid cesium injected by the injector 37 is vaporized, the vaporization efficiency of cesium can be improved.

In other words, the amount of cesium gas discharged depends on the amount of pressure gas and the degree of vaporization of cesium, and the degree of vaporization of cesium depends on the particle size and spreading degree of the liquid cesium injected by the injector 37.

In addition, since the first, second, and third flow tubes 32, 33, and 38 may be maintained at a high temperature to prevent clogging due to cesium oxidation, a vacuum system, for example, a chamber of the deposition apparatus 43 may be of high quality. Cesium gas is supplied to facilitate the generation of anions on the substrate to be treated.

In addition, since the cesium gas is supplied to the deposition apparatus together with the inert gas, it is possible to prevent the inflow of oxygen or oxidizing material so that the cesium gas can be used stably for a long time without altering the cesium.

That is, when the cesium is vaporized using the cesium supply device according to the present invention, it is possible to continuously and stably supply a large amount of cesium gas for a long time than the prior art.

The cesium supply device according to the present invention as described above has the following effects.

First, by installing an injector for injecting liquid cesium to vaporize the fine liquid cesium particles, it is possible to increase the vaporization efficiency, thereby supplying a large amount of cesium gas to the deposition apparatus.

Second, since the pressure gas supplied to the cesium storage unit is controlled by using a pressure gas control device, the amount of liquid cesium supplied to the injector can be adjusted, and as a result, the amount of cesium gas supplied to the deposition apparatus can be controlled.

Third, by installing a heater or heating wire to control and maintain the temperature of the entire system including the preheater, cesium vaporization unit and flow tube, and to supply the cesium gas with the inert gas argon gas to the deposition apparatus, to prevent the oxidation of cesium can do. Therefore, cesium gas can be stably supplied for a long time without alteration.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the examples, but should be defined by the claims.

Claims (16)

Gas flow control unit for controlling the amount of inert gas injected from the outside, A preheater for preheating the inert gas injected from the gas flow controller through the first flow pipe; Cesium storage unit for discharging cesium by the pressure gas supplied through the pressure gas supply pipe, An injector that receives cesium from the cesium storage unit and sprays the cesium; And a cesium vaporizer which vaporizes cesium injected from the injector and discharges cesium gas through the third flow tube together with the inert gas injected from the preheater through the second flow tube. The method of claim 1, The injector is cesium supply apparatus, characterized in that controlled by a pulse signal applied from the outside. The method of claim 1, The injector is cesium supply apparatus, characterized in that for controlling the particle size, amount, degree of spread of the cesium is injected. The method of claim 1, The inert gas is cesium supply device, characterized in that selected from the group consisting of argon gas, nitrogen gas, helium gas. The method of claim 1, Cesium supply device, characterized in that the cesium stored in the cesium storage unit in a liquid state. The method of claim 1, Cesium storage unit is characterized in that the interior of the cesium storage unit is maintained at a temperature of 27 ℃ or more. The method of claim 1, The cesium vaporization unit is cesium supply apparatus, characterized in that maintained at a temperature of 200-300 ℃. The method of claim 1, The cesium supply apparatus, characterized in that the pressure gas is an inert gas. The method of claim 8, The cesium supply device, characterized in that the inert gas is N ₂ . The method of claim 1, The cesium supply apparatus further comprises a heater for heating each of the preheating unit, cesium storage unit, and the cesium vaporization unit. The method of claim 1, Cesium supply device further comprises a heating wire for heating the first, second, third flow pipe. The method of claim 1, Cesium supply device further comprises a valve installed in each of the second and third flow pipe. The method of claim 1, Cesium supply device further comprises a pressure gas control device for adjusting the amount of pressure gas injected into the cesium storage. A first step of adjusting the amount of inert gas injected from the outside, A second step of preheating the inert gas, A third step of vaporizing the cesium supplied by the pressure gas, followed by vaporization; And a fourth step of discharging the vaporized cesium together with the preheated inert gas. The method of claim 14, In the third step, the cesium supply method characterized in that the spray periodically. The method of claim 14, In the third step, the cesium supply method characterized in that to control the amount of cesium to be injected by adjusting the amount of pressure gas.