JP2010272228A - Ion source device, ion generation method, ion implantation device, and ion implantation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion source device and an ion generation method, for stabilizing a supply volume of a raw material, eventually for stably generating ion, and an ion implantation device equipped with the ion source device, as well as an ion implantation method generating ions by the ion generation method. <P>SOLUTION: The invention includes an orifice plate 31 inside a piping 24 connecting a raw material vessel 22 and an arc chamber 23, aluminum chloride gas 8 generated at the raw material vessel 22 is made flow falling through a communication hole formed on the orifice plate 31. With this, inside the raw material vessel 22, pressure rises to be higher than the pressure liquefying the aluminum chloride, thus the solid aluminum chloride becomes aluminum chloride liquid 27. The aluminum chloride gas 8 generated by evaporation of the aluminum chloride liquid 27 is supplied to the arc chamber 23. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ion source apparatus and an ion generation method, and an ion implantation apparatus and an ion implantation method. More specifically, the present invention relates to an ion source apparatus and an ion generation method that can be suitably used for aluminum ion implantation in the manufacture of semiconductor devices. The present invention also relates to an ion implantation apparatus including the ion source apparatus and an ion implantation method for generating ions by the ion generation method.

  In an ion implantation apparatus used for manufacturing a semiconductor device, an electron collision type ion source is mainly used. In an electron collision type ion source, a current of several hundred amperes (A) is passed through a filament to emit thermoelectrons, and at the same time, a gas to be ionized is introduced into a space to which a magnetic field is applied from the outside. To generate ions. Ion implantation is performed using the ions thus generated (see, for example, Non-Patent Document 1).

  When a silicon carbide (SiC) device is manufactured, aluminum (Al) ions are implanted as a p-type impurity into the SiC substrate using the above-described ion implantation apparatus. As methods for generating aluminum ions, there are first to fourth methods described below.

As a first method, a vapor is generated by raising the temperature of a sublimable solid containing Al at room temperature and normal pressure, such as aluminum chloride (AlCl ₃ ) or aluminum fluoride (AlF ₃ ). There is a method (for example, see Non-Patent Document 2) in which this vapor is introduced into an arc chamber as a raw material and ionized.

As a second method, an organic metal which is liquid at room temperature and normal pressure and contains Al, such as trimethylaluminum [(CH ₃ ) ₃ Al] ₂ or triethylaluminum [(C ₂ H ₃ ) ₃ Al] _2, etc. There is a method of ionizing a liquid in which the liquid is dissolved by bubbling with a carrier gas such as nitrogen (N ₂ ) or argon (Ar) to the arc chamber.

  As a third method, there is a method in which the inner wall of an arc chamber formed of a corroded aluminum compound is sputtered to generate Al atoms and Al molecules and collide with each other to generate aluminum ions (for example, , See Patent Document 1).

  Further, as a fourth method, there is a method in which aluminum ions are directly generated by sputtering from the inner wall of an arc chamber made of aluminum metal (see, for example, Patent Document 2).

JP 11-238485 A Japanese Patent Laid-Open No. 11-144636

“2007 Complete Semiconductor Technology”, Electronic Journal, Inc., May 22, 2007, p314-315 Kohei Sekine, 2 others, “Examination of generation method of aluminum ions A1 + and Al2 +”, Proceedings of the 50th Joint Symposium on Applied Physics in Spring 2003, Japan Society of Applied Physics, 2003, No. 2, p. 788 (29a-YH-3)

In the second method described above, an organic metal such as trimethylaluminum [(CH ₃ ) ₃ Al] ₂ that is a raw material of aluminum ions is extremely reactive and may explode. There is a problem that a raw material supply device becomes large and is difficult to be incorporated into an ion source device and an ion implantation device.

  In the third and fourth methods described above, the inner wall of the arc chamber is formed of a corroded aluminum compound or aluminum metal, and the melting point is relatively low at 660 degrees. Therefore, the amount of aluminum ions generated by arc discharge is reduced. May be useful if you want more. However, in the third and fourth methods, since the raw material is supplied from the inner wall of the chamber, it is difficult to control the generation amount of aluminum ions because the wall surface becomes rough or the inner wall surface is altered. There is a problem.

  Of the sublimable solids used in the first method described above, aluminum fluoride has a low vapor pressure during sublimation, so it needs to be raised to a high temperature in order to obtain a sufficient ion beam current. Ingenuity is required.

  On the other hand, since aluminum chloride has a low sublimation temperature, a sufficient amount of sublimation can be easily obtained, and an ion beam current can be obtained. However, there is a problem that the supply amount is not stable when used for a long time.

  Specifically, in the first method, a raw material container filled with aluminum chloride powder, which is a sublimable solid, is heated to sublimate aluminum chloride. When used for a long time, the filling amount of the aluminum chloride powder in the raw material container is reduced by sublimation, and accordingly, a gap is generated between the powders, resulting in uneven heating. Due to this uneven heating, the heating efficiency is reduced and the amount of sublimation is greatly reduced. Therefore, it is difficult to stably control the sublimation amount, that is, the supply amount of the raw material, and there arises a problem that the aforementioned supply amount is not stable.

  Thus, even when aluminum chloride is used as a sublimable solid, the amount of sublimation of aluminum chloride becomes unstable, the supply amount of raw materials is not stable, and aluminum ions cannot be generated stably. .

  Therefore, an object of the present invention is to stabilize the supply amount of raw materials, and thus to stably generate ions, an ion generation method, an ion implantation apparatus including the ion source device, and the ion source To provide an ion implantation method for generating ions by an ion generation method.

  An ion source apparatus according to the present invention includes a raw material container in which raw materials are stored, a heating unit that heats the raw material stored in the raw material containers to generate vapor of the raw materials, and a raw material by the heating unit. An ion generating means for generating ions from the vapor of the raw material contained in the chamber, and a pressure in the raw material container, the chamber containing the vapor of the raw material generated and supplied in the container; Pressure holding means capable of holding at a pressure equal to or higher than the pressure at which the liquid is liquefied.

  An ion implantation apparatus according to the present invention includes the ion source device and an implantation unit that implants ions generated by an ion generation unit of the ion source device into an object to be implanted.

  In the ion generation method of the present invention, a solid-state raw material housed in a raw material container is heated to generate a vapor of the raw material, and ions are generated from the raw material vapor generated in the vapor generation step. A step of generating ions, wherein the raw material is heated in a state where the pressure in the raw material container can be maintained at a pressure equal to or higher than the pressure at which the raw material is liquefied.

  The ion implantation method of the present invention is characterized in that ions are generated by the ion generation method and the generated ions are injected into an object to be implanted.

  According to the ion source device of the present invention, the solid state raw material accommodated in the raw material container is heated by the heating means, and the vapor of the raw material is generated and supplied to the chamber of the ion generating means. Ions are generated from the vapor of the supplied raw material by the ion generating means. The pressure in the raw material container can be maintained at a pressure higher than the pressure at which the raw material is liquefied by the pressure holding means. Therefore, when the raw material in the solid state is heated and sublimated to generate the raw material vapor, the raw material container The internal pressure rises and reaches a pressure higher than the pressure at which the raw material liquefies. As a result, the raw material in the solid state becomes a liquid state, so that the vapor generated by the evaporation of the raw material in the liquid state is supplied to the ion generating means.

  Therefore, compared with the case where the raw material vapor is sublimated and the raw material vapor is supplied to the ion generating means, the heating state of the raw material can be stabilized, so that the supply amount of the raw material to the ion generating means can be accurately set. The ions can be controlled and ions can be generated stably.

  According to the ion implantation apparatus of the present invention, ions are stably generated by the ion generation means of the ion source apparatus as described above, and are injected into the injection target by the injection means. Thereby, ions can be stably injected into the injection target.

  According to the ion generation method of the present invention, in the steam generation step, the raw material in a solid state accommodated in the raw material container is heated to generate the raw material vapor. Ions are generated from the generated raw material vapor in an ion generation step. In the steam generation step, the raw material is heated in a state where the pressure in the raw material container can be maintained at a pressure equal to or higher than the pressure at which the raw material liquefies. When this occurs, the pressure in the raw material container can be increased by the steam, and the pressure can be made higher than the pressure at which the raw material is liquefied. As a result, the raw material in the solid state is liquefied to be in a liquid state, so that the vapor generated by the evaporation of the raw material in the liquid state is subjected to the ion generation step.

  Therefore, since the heating state of the raw material can be stabilized compared with the case where the vapor generated by sublimation of the raw material in the solid state is supplied to the ion generation step, the supply amount of the raw material supplied to the ion generation step can be reduced. It can be controlled accurately. As a result, the amount of raw material supplied to the ion generation step can be stabilized, so that ions can be generated stably.

  According to the ion implantation method of the present invention, ions are generated by the ion generation method capable of stably generating ions as described above, and are injected into the injection target. Thereby, ions can be stably injected into the injection target.

It is sectional drawing which shows typically the structure of the conventional ion source apparatus 1 of the ion implantation apparatus used as the premise of this invention. It is sectional drawing which shows typically the structure of the ion source apparatus 21 of the ion implantation apparatus 20 which is the 1st Embodiment of this invention. It is a side view which shows typically the structure of the ion implantation apparatus 20 which is the 1st Embodiment of this invention. It is sectional drawing which shows typically the structure of the ion source apparatus 50 of the ion implantation apparatus in the 2nd Embodiment of this invention. It is sectional drawing which shows typically the structure of the ion source apparatus 60 of the ion implantation apparatus in the 3rd Embodiment of this invention. It is sectional drawing which shows typically the structure of the ion source apparatus 70 of the ion implantation apparatus in the 4th Embodiment of this invention.

<Prerequisite technology>
Before describing the ion implantation apparatus of the present invention, the ion implantation apparatus as a premise of the present invention will be described. FIG. 1 is a cross-sectional view schematically showing a configuration of a conventional ion source device 1 of an ion implantation apparatus as a premise of the present invention.

  In the ion implantation apparatus of the base technology, in the ion source apparatus 1, the raw material container 2 containing the aluminum chloride solid powder 7 is heated by the container heating unit 32 surrounding the raw material container 2, and the aluminum chloride gas is heated. 8 is generated by sublimation, and an aluminum chloride gas 8 is introduced into the arc chamber 3 through the pipe 4. The aluminum chloride gas 8 introduced into the arc chamber 3 is ionized by arc discharge by the thermoelectrons 9 generated in the filament 6 to become aluminum ions 10.

  The aluminum ions 10 thus generated by the ion source device 1 are extracted from the arc chamber 3 by the extraction plate 5 and obtain desired acceleration energy through a mass analysis unit and an acceleration tube (not shown). Ions are implanted into a semiconductor substrate installed at the end station.

  In the ion implantation apparatus of the base technology, a solid powder of aluminum chloride (hereinafter sometimes simply referred to as “solid powder”) 7 is used as a supply source of the aluminum chloride gas 8. When used for a long time, the filling amount of the aluminum chloride solid powder 7 in the raw material container 2 is reduced by sublimation, so that a gap is generated between the solid powder 7 and the solid powder 7, thereby causing uneven heating. . Due to the unevenness of heating, the heating efficiency is reduced and the sublimation amount is greatly changed. Therefore, it is difficult to stably control the sublimation amount, that is, the supply amount of the raw material, and there is a problem that the supply amount of the raw material is not stable.

  Therefore, the ion implantation apparatus of the present invention employs the configuration of each embodiment shown below.

<First Embodiment>
FIG. 2 is a cross-sectional view schematically showing the configuration of the ion source device 21 of the ion implantation apparatus 20 according to the first embodiment of the present invention. FIG. 3 is a side view schematically showing the configuration of the ion implantation apparatus 20 according to the first embodiment of the present invention. The ion implantation apparatus 20 includes an ion source device 21, a mass analysis unit 40, an acceleration tube 41, a scanner unit 42, and an end station 43. The mass analyzer 40, the acceleration tube 41, and the scanner unit 42 correspond to injection means. Since the ion implantation apparatus according to the present embodiment is similar to the above-described ion implantation apparatus of the base technology, the same reference numerals are given to corresponding portions, and description common to the base technology is omitted.

  The ion source device 21 includes a raw material container 22, an arc chamber 23, a pipe 24 connecting the raw material container 22 and the arc chamber 23, a drawing plate 5, a filament 6 provided in the internal space of the arc chamber 23, and a raw material And a container heating unit 32 that surrounds the container 22. The container heating unit 32 corresponds to a heating unit. The arc chamber 23 and the filament 6 correspond to ion generating means. It is assumed that the filament 6 is insulated from the raw material container 22.

  The raw material container 22 contains raw materials, in this embodiment, aluminum chloride. The raw material container 22 is configured to be sealable and removable. The raw material is charged into the raw material container 22 in a solid state.

  The container heating unit 32 is a heater made of, for example, carborundum or the like, and is supplied with power from a container heating power source (not shown) to generate heat and heat the raw material container 22. The container heating unit 32 heats the raw material container 22 to heat the raw material in the solid state accommodated in the raw material container 22 and sublimate the raw material, thereby vaporizing the raw material, in this embodiment, aluminum chloride. Gas 8 is generated.

The arc chamber 23 accommodates the raw material vapor generated and supplied in the raw material container 22 in an inner space. The arc chamber 23 is formed of a conductive material, and is used with a positive voltage of several hundred volts applied to the filament 6. The arc chamber 23 is used in a vacuum state in which an inner space is evacuated, that is, vacuumed by a vacuum pump (not shown). Here, the “vacuum state” is a state where the pressure is lower than the standard atmospheric pressure (1.013 × 10 ⁵ Pa). The arc chamber 23 is used in a vacuum state of, for example, a pressure of 1 × 10 ⁻⁵ Pa to 1 × 10 ⁻² Pa.

  A filament power source (not shown) is connected to the filament 6 provided in the internal space of the arc chamber 23, and a current of several tens to several hundreds of amperes (A) flows. As a result, thermoelectrons 9 are generated and arc discharge occurs.

  The pipe 24 supplies the arc chamber 23 with an aluminum chloride gas 8 that is a raw material vapor generated in the raw material container 22. An orifice plate 31 is provided inside the pipe 24. The orifice plate 31 corresponds to pressure holding means. More specifically, the orifice plate 31 corresponds to a flow-down resistance means, and functions as a resistance when the raw material vapor 8 flows down the pipe 24 by being provided inside the pipe 24.

  The orifice plate 31 is a partition member, and partitions the pipe 24 into a container side connection portion connected to the raw material container 22 and a chamber side connection portion connected to the arc chamber 23. The orifice plate 31 is provided in the vicinity of the center between one end of the pipe 24 connected to the raw material container 22 and the other end connected to the arc chamber 23.

  The orifice plate 31 is formed in a disc shape, and a communication hole for communicating the container side connecting portion and the generating means side connecting portion is formed at the center thereof. If the communication hole is large, it is difficult to create a pressure difference between the raw material container 22 and the arc chamber 23. Therefore, the communication hole is preferably small. Therefore, the communication hole may not be a single hole but may be a ring-shaped communication hole like an opening of a needle valve. The aluminum chloride gas 8 generated in the raw material container 22 flows down from the container side connection portion of the pipe 24 to the generation means side connection portion of the pipe 24 through the communication hole of the orifice plate 31 and is supplied to the arc chamber 23.

  When the ion implantation apparatus 20 is used, the arc chamber 23 serving as an ion generation source is evacuated as described above and is in a vacuum state. In a state at the start of use of the ion implantation apparatus 20, the raw material container 22 is filled with solid aluminum chloride as a raw material. Since the raw material container 22 and the arc chamber 23 are connected by a pipe 24, if the orifice plate 31 is not provided in the pipe 24, the raw material container 22 is also in a vacuum state or a state close thereto.

  On the other hand, in the present embodiment, the orifice plate 31 is provided in the vicinity of the central portion between both ends of the pipe 24 connecting the raw material container 22 and the arc chamber 23. Since the orifice plate 31 functions as a resistance when the raw material vapor 8 flows down the pipe 24, by providing the orifice plate 31, the pressure in the raw material container 22 is increased, and the space and pressure inside the arc chamber 23 are increased. A difference can be made. Specifically, a pressure difference of about 3 atmospheres can be generated in the raw material container 22.

  Thereby, the pressure in the raw material container 22 (hereinafter sometimes referred to as “internal pressure of the raw material container”) can be maintained at a pressure higher than the pressure at which the raw material is liquefied. That is, the raw material accommodated in the raw material container 22 can be liquefied into the raw material in a liquid state, that is, the aluminum chloride liquid 27 in the present embodiment.

  More specifically, the raw material container 22 is heated by the container heating unit 32 from the state when the ion implantation apparatus 20 starts to be used, and the temperature is raised to about 200 ° C. in the present embodiment. Then, the solid aluminum chloride gradually sublimates and the internal pressure of the raw material container 22 increases. When the internal pressure of the raw material container 22 reaches about 2 atm, the solid aluminum chloride is liquefied and becomes the aluminum chloride liquid 27. Since the aluminum chloride gas 8 is generated from the aluminum chloride liquid 27, the pressure in the raw material container 22 is maintained at a pressure of 2 atmospheres or more, which is a pressure at which aluminum chloride can be liquefied.

  Accordingly, the aluminum chloride gas 8 evaporated from the aluminum chloride liquid 27 is supplied to the arc chamber 23 via the pipe 24. After the aluminum chloride is liquefied, the aluminum chloride liquid 27 accommodated in the raw material container 22 is supplied by the container heating unit 32 via the raw material container 22 in an amount of aluminum chloride gas 8 necessary for obtaining a desired ion beam current. Is maintained at a temperature at which it can be generated, specifically 200 ° C. or higher. The step of generating the aluminum chloride gas 8 which is the raw material vapor in this way corresponds to the vapor generation step.

The inner diameter and length of the pipe 24, and the orifice diameter, which is the diameter of the communication hole formed in the orifice plate 31, are the amount of aluminum chloride necessary to obtain a desired ion beam current in a state where the aluminum chloride is liquefied. The gas 8 is selected to be supplied to the arc chamber 23. Specifically, it is selected so that an aluminum chloride gas 8 of several sccm or more and tens of sccm or less, more specifically 2 to 30 × 10 ⁻⁴ Pa · m ³ / sec or less, is supplied to the arc chamber 23. . The pipe 24 is formed with a uniform inner diameter. The thickness of the pipe wall of the pipe 24 is selected so as to withstand the pressure difference generated between the raw material container 22 and the arc chamber 23.

  The sccm (Standard cc per minute) is a unit representing the gas flow rate (cc / min), and the gas flow rate when the volume of the gas flowing per minute is converted into a state of 0 ° C. and 1 atm (101325 Pa). It is a unit representing.

  The aluminum chloride gas 8 supplied to the arc chamber 23 in this way is ionized by arc discharge by the thermoelectrons 9 generated in the filament 6 to become aluminum ions (hereinafter sometimes referred to as “Al ions”) 10. . The step of generating aluminum ions 10 as target ions in this way corresponds to the ion generation step.

  Ions including Al ions 10 generated in the arc chamber 23 are extracted from the arc chamber 23 by the extraction plate 5 and applied to the mass analyzer 40 shown in FIG. The mass analysis unit 40 selects and separates target ions (hereinafter sometimes referred to as “target ions”) from the given ions, Al ions 10 in the present embodiment, and gives them to the acceleration tube 41.

  In the arc chamber 23 of the ion source device 21, in addition to the target Al ion 10, ions having a mass greater than that of the Al ion and ions having a mass smaller than that of the Al ion are generated. The aluminum ions 10 pass through the mass analyzer 40 while drawing a locus indicated by the reference symbol a in FIG. 3 and reach the acceleration tube 41.

  Since ions having a mass greater than that of the Al ions are captured outside the bent portion in the mass analyzing unit 40 along the locus indicated by the reference symbol b in FIG. 3, they cannot pass through the mass analyzing unit 40. . Ions that are lighter than the Al ions are trapped inside the bent portion along the locus indicated by the reference symbol c in FIG. 3 in the mass analyzer 40, and therefore cannot pass through the mass analyzer 40.

  Therefore, only the aluminum ions 10 are guided to the acceleration tube 41. The Al ions 10 guided to the accelerating tube 41 pass through the accelerating tube 41 to obtain a desired acceleration energy, are scanned by the scanner unit 42, and are an SiC substrate, which is an injection target set in the end station 43, or the like. The semiconductor substrate 44 is implanted.

  As described above, according to the ion source device 21 of the present embodiment, the aluminum chloride solid that is the raw material in the solid state accommodated in the raw material container 22 is heated, and the aluminum chloride gas 8 that is the raw material vapor is generated. , Supplied to the arc chamber 23. Aluminum ions 10 are generated from the supplied aluminum chloride gas 8.

  In the present embodiment, since the orifice plate 31 is provided inside the pipe 24, the orifice plate 31 holds the pressure in the raw material container 22 at a pressure higher than the pressure at which the raw material aluminum chloride is liquefied. Is possible.

  That is, when the aluminum chloride solid is heated and sublimated to generate the aluminum chloride gas 8, the pressure in the raw material container 22 is increased by the aluminum chloride gas 8 to a pressure higher than the pressure at which the aluminum chloride liquefies. it can. As a result, the aluminum chloride solid is liquefied and becomes a liquid aluminum chloride liquid 27, and thus the aluminum chloride gas 8 generated by the evaporation of the aluminum chloride liquid 27 is supplied to the arc chamber 23.

  Therefore, compared with the case where the aluminum chloride gas 8 generated by sublimating the aluminum chloride solid 7 is supplied to the arc chamber 3 as in the ion source apparatus 1 of the base technology shown in FIG. Therefore, the supply amount of aluminum chloride to the arc chamber 23 can be accurately controlled. Thereby, since the supply amount of aluminum chloride to the arc chamber 23 can be stabilized, the aluminum ions 10 can be stably generated.

  Since the ion implantation apparatus 20 of the present embodiment is configured by including the ion source device 21 that can stably generate the aluminum ions 10 as described above, the semiconductor substrate 44 that is an implantation target has Aluminum ions 10 that are ions to be implanted can be stably implanted.

  Further, the ion source device 21 of the present embodiment has another advantage. That is, when the raw material in the raw material container 22 is used and reduced, the raw material container 22 can be easily refilled with the raw material.

  In the prior art ion source device, the evacuated arc chamber and the raw material container are integrated, so that the arc chamber needs to be released to the atmosphere in order to refill the raw material container. When the arc chamber is released to the atmosphere, it is necessary to assemble a part such as a sealing packing to the arc chamber and to evacuate it again when it is used again. This operation reduces the operating rate of the outgas device connected to the arc chamber. Therefore, the production efficiency of the semiconductor is reduced.

  On the other hand, in the ion source device 21 of the present embodiment, the orifice plate 31 is provided in the pipe 24 that connects the raw material container 22 and the arc chamber 23 that is the ion source, and resistance to the gas flowing down the pipe 24. Therefore, even if the raw material container 22 is removed, the flow rate of the gas flowing out from one end of the pipe 24 is several sccm to several tens sccm. Therefore, even if the raw material container 22 is removed while the arc chamber 23 is evacuated, an exhaust system including a vacuum pump such as a turbo pump that evacuates the arc chamber 23 is not damaged, and the aluminum chloride solid material is a raw material. The powder can be easily refilled into the raw material container 22.

<Second Embodiment>
FIG. 4 is a cross-sectional view schematically showing the configuration of the ion source device 50 of the ion implantation apparatus according to the second embodiment of the present invention. Since the ion implantation apparatus according to the present embodiment is similar to the ion implantation apparatus 20 according to the first embodiment described above, the same reference numerals are assigned to corresponding portions, and the same as the first embodiment. Description to be omitted is omitted.

  The ion source device 50 of the present embodiment includes a gas supply unit 54 that is a pressurized gas supply unit. The gas supply unit 54 is connected to the raw material container 22, and supplies the pressurized gas 52 to the raw material container 22 to supply the pressurized gas 52 for pressurizing the inside of the raw material container 22, and supplies the pressurized gas 52 to the gas introducing pipe 51. And a pressurized gas source 53. As the pressurized gas 52, argon (Ar) gas or the like is used.

  When the raw material container 22 is heated by the container heating unit 32 from the state at the start of use of the ion implantation apparatus and heated to about 200 ° C., the solid aluminum chloride gradually sublimates, and the raw material container 22 The internal pressure rises. In the present embodiment, when the raw material container 22 is heated, a pressurized gas 52 such as Ar gas is introduced into the raw material container 22 through the gas introduction pipe 51.

  Thus, by introducing the pressurized gas 52 from the outside of the raw material container 22, not only the pressure increase due to the aluminum chloride gas 8 generated by the sublimation of aluminum chloride but also the raw material due to the pressure increase due to the introduction of the pressurized gas 52. The liquefaction of certain aluminum chloride can be promoted.

  The amount of the pressurized gas 52 introduced into the raw material container 22 is not an amount necessary as a carrier gas for transporting the aluminum chloride gas 8 to the arc chamber 23, but is necessary for increasing the internal pressure of the raw material container 22. Chosen in quantity.

  In this way, the aluminum chloride, which was solid at the beginning of heating, is liquefied when the temperature in the raw material container 22 rises to a pressure of about 2 atm. The inner diameter and length of the pipe 24 and the orifice diameter of the orifice plate 31 are the amounts necessary for obtaining a desired ion beam current in a state where the aluminum chloride is liquefied, that is, an aluminum chloride gas of several sccm to several tens sccm. 8 is selected to be supplied to the arc chamber 23. The pipe 24 is formed with a uniform inner diameter. The thickness of the pipe wall of the pipe 24 is selected so as to withstand the pressure difference generated between the raw material container 22 and the arc chamber 23.

  In this way, the aluminum chloride gas 8 supplied to the arc chamber 23 is ionized by arc discharge by the thermoelectrons 9 generated in the filament 6 to become aluminum ions 10. Similarly to the first embodiment, only the Al ions 10 out of the ions including the Al ions 10 pass through the mass analysis unit 40 and pass through the acceleration tube 41 to obtain desired acceleration energy, and the scanner unit 42. And is ion-implanted into a semiconductor substrate 44 such as a SiC substrate installed in the end station 43.

  As described above, in the ion source device 51 of the present embodiment, the pressurized gas 52 is introduced into the raw material container 22 by the gas supply unit 54 via the gas introduction pipe 51, so that the pressure in the raw material container 22 is increased. , Liquefaction of raw materials can be promoted. Therefore, since the supply amount of the raw material to the arc chamber 23 can be further stabilized, the aluminum ions 10 can be generated more stably.

<Third Embodiment>
FIG. 5 is a cross-sectional view schematically showing the configuration of the ion source device 60 of the ion implantation apparatus according to the third embodiment of the present invention. Since the ion implantation apparatus according to the present embodiment is similar to the ion implantation apparatuses according to the first and second embodiments described above, the same reference numerals are assigned to corresponding portions, and the first and second ion implantation apparatuses are denoted by the same reference numerals. The description common to the embodiment is omitted.

  The ion source device 60 of the present embodiment includes a heat retaining unit 61 that is a heat retaining means. The heat retaining unit 61 includes a tube heating unit 62 disposed so as to surround the linear portion of the pipe 24, and a heat equalizing tube 63 disposed between the pipe 24 and the tube heating unit 62.

  The tube heating unit 62 is a heater made of, for example, carborundum or the like, and is supplied with electric power from a tube heating power source (not shown) to generate heat and heat the soaking tube 63 and the pipe 24. The soaking tube 63 is a cylindrical member made of, for example, stainless steel. The soaking tube 63 is heated by the heat generated by the tube heating unit 62 to increase the temperature, and heats the pipe 24 arranged radially inward of the soaking tube 63 by the heat transmitted from the soaking tube 63. Thereby, the pipe 24 is kept at a temperature equal to or higher than a certain temperature, and the internal space of the pipe 24, that is, the flow path in the pipe 24 is kept at a temperature equal to or higher than the certain temperature. Specifically, the piping 24 and its internal space are kept at a temperature equal to or higher than the temperature at which aluminum chloride molecules are solidified under vacuum.

  Thus, in the present embodiment, the pipe 24 is kept at a temperature equal to or higher than the temperature at which the aluminum chloride molecules are solidified under vacuum, and the aluminum chloride gas 8 generated in the raw material container 22 is in the middle of the pipe 24. It can be prevented from solidifying. As a result, the aluminum chloride, which is a raw material, can be supplied to the arc chamber 23 as the aluminum chloride gas 8 without being attached to the inside of the pipe 24 as a solid.

  Therefore, since the supply amount of the raw material to the arc chamber 23 can be further stabilized, the aluminum ions 10 can be generated more stably.

  In the first to third embodiments described above, the orifice plate 31 is provided as the flow resistance means. The flow resistance means is not limited to the orifice plate 31, and may be any function as long as it functions as a resistance when the raw material vapor 8 flows down the pipe 24. For example, a protrusion that protrudes inward in the radial direction of the pipe 24 may be formed inside the pipe 24 as a flow-down resistance means.

<Fourth embodiment>
FIG. 6 is a cross-sectional view schematically showing a configuration of an ion source device 70 of an ion implantation apparatus according to the fourth embodiment of the present invention. Since the ion implantation apparatus according to the present embodiment is similar to the ion implantation apparatuses according to the first and second embodiments described above, the same reference numerals are assigned to corresponding portions, and the first and second ion implantation apparatuses are denoted by the same reference numerals. The description common to the embodiment is omitted.

  In the ion source device 70 of the present embodiment, the pipe 71 functions as a pressure holding unit. The pipe 71 is formed such that the inner diameter R1 of the container side connecting portion 72 connected to the raw material container 22 is smaller than the inner diameter R2 of the chamber side connecting portion 73 connected to the arc chamber 23 (R1 <R2). Hereinafter, the container side connection portion 72 may be referred to as a small diameter portion, and the chamber side connection portion 73 may be referred to as a large diameter portion.

  That is, the pipe 71 has a small diameter portion 72 and a large diameter portion 73. The small diameter portion 72 and the large diameter portion 73 are connected in the vicinity of the center between both ends of the pipe 71. The pipe 71 has a gradually changing inner diameter at the connecting portion between the small diameter portion 72 and the large diameter portion 73. Here, “the inner diameter R1 of the small diameter portion 72” refers to the maximum value of the inner diameter of the small diameter portion 72, and “the inner diameter R2 of the large diameter portion 73” refers to the maximum value of the inner diameter of the large diameter portion 73.

  The inner diameter R1 of the small diameter portion 72 of the pipe 71 is selected to be smaller than the inner diameter R0 of the pipe 24 in the second embodiment shown in FIG. The inner diameter R2 of the large-diameter portion 73 of the pipe 71 is selected to be approximately the same as the inner diameter R0 of the pipe 24 in the above-described second embodiment. In other words, the pipe 71 has a shape in which the inner diameter of the pipe 24 in the above-described second embodiment is increased only in the portion on the arc chamber 23 side that is the ion generating portion, in other words, the inner diameter only in the portion on the raw material container 22 side. Formed in a reduced shape.

  Thus, in the present embodiment, the pipe 71 is formed in the pipe 71 because the inner diameter R1 of the container side connection portion 72 is smaller than the inner diameter R2 of the chamber side connection portion 73 (R1 <R2). The container-side connection portion 72 is smaller in cross-sectional area of the flow path than the chamber-side connection portion 73. In the container-side connecting portion 72 having the small inner diameter R1, the vapor 8 of the raw material generated in the raw material container 22 is less likely to flow down than in the chamber-side connecting portion 73. A pressure difference can be generated with the space inside the chamber 23.

  Specifically, as in the case where the orifice plate 31 is provided in the pipe 24 in the first and second embodiments, a pressure difference of about 3 atmospheres can be generated in the raw material container 22 with respect to the vacuum state. . As a result, the pressure in the raw material container 22 can be maintained at a pressure equal to or higher than the pressure at which the raw material is liquefied. Therefore, the raw material stored in the raw material container 22 can be liquefied into the aluminum chloride liquid 27. Is possible.

  Therefore, when the raw material container 22 is heated to sublimate solid aluminum chloride from the state when the ion implantation apparatus 20 starts to be used, and the aluminum chloride gas 8 is generated, the internal pressure of the raw material container 22 is increased, and 3 It can be near atmospheric pressure. As a result, the solid aluminum chloride can be liquefied into the aluminum chloride liquid 27, so that the aluminum chloride gas 8 evaporated from the aluminum chloride liquid 27 can be supplied to the arc chamber 23 via the pipe 71. it can.

  Thus, as compared with the case where the aluminum chloride gas 8 generated by sublimating the aluminum chloride solid 7 is supplied to the arc chamber 3 as in the ion source device 1 of the base technology shown in FIG. Since the heating state of aluminum can be stabilized, the supply amount of aluminum chloride to the arc chamber 23 can be accurately controlled. Thereby, since the supply amount of aluminum chloride to the arc chamber 23 can be stabilized, the aluminum ions 10 can be stably generated.

  Further, in the present embodiment, as in the second embodiment, the pressurized gas 52 is introduced into the raw material container 22 by the gas supply unit 54 via the gas introduction pipe 51, so that the pressure in the raw material container 22 is increased. And liquefaction of raw materials can be promoted. Therefore, since the supply amount of the raw material to the arc chamber 23 can be further stabilized, the aluminum ions 10 can be generated more stably.

The inner diameter R1 of the small-diameter portion 72 and the inner diameter R2 of the large-diameter portion 73 and the piping length of the piping 71 are the amount of aluminum chloride necessary to obtain a desired ion beam current in a state where the aluminum chloride is liquefied. The gas 8 is selected to be supplied to the arc chamber 23. Specifically, it is selected so that an aluminum chloride gas 8 of several sccm or more and tens of sccm or less, more specifically 2 to 30 × 10 ⁻⁴ Pa · m ³ / sec or less, is supplied to the arc chamber 23. . The thickness of the pipe wall of the pipe 71 is selected so as to withstand the pressure difference generated between the raw material container 22 and the arc chamber 23.

  In the present embodiment described above, the orifice plate is not provided in the pipe 71, but an orifice plate may be provided. Thereby, the pressure in the raw material container 22 can be increased and liquefaction of the raw material can be promoted. Therefore, since the supply amount of the raw material to the arc chamber 23 can be further stabilized, the aluminum ions 10 can be generated more stably.

  Moreover, you may provide the thermal insulation part which heats the piping 71 around the piping 71 similarly to 3rd Embodiment. Thereby, the aluminum chloride as the raw material can be supplied to the arc chamber 23 as the aluminum chloride gas 8 without being attached to the inside of the pipe 71 as a solid. Therefore, since the supply amount of the raw material to the arc chamber 23 can be further stabilized, the aluminum ions 10 can be generated more stably.

  The ion implantation apparatus including the ion source devices 21, 50, 60, and 70 according to the first to fourth embodiments described above is preferably used for aluminum ion implantation. The use of the ion implantation apparatus of the present invention is not limited to aluminum ion implantation. The ion implantation apparatus of the present invention can be used as long as the raw material of the target ions generated by the ion source devices 21, 50, 60, and 70 is a sublimable solid.

  In the present embodiment, the inside of the raw material container 22 is described as being heated to 200 ° C. or higher and increased to about 2 atm. However, the temperature and pressure conditions are different as long as aluminum chloride can be liquefied. Condition may be sufficient.

  1,2,50,60,70 Ion source device, 2,22 Raw material container, 3,23 Arc chamber, 4,24,71 piping, 8 Aluminum chloride gas, 10 Aluminum ion, 20 Ion implanter, 27 Aluminum chloride liquid , 31 Orifice plate, 32 Container heating section.

Claims (10)

A raw material container for containing the raw material;
Heating means for heating the raw material in a solid state contained in the raw material container to generate vapor of the raw material;
An ion generating means for generating ions from the raw material vapor stored in the chamber, the chamber containing the raw material vapor generated and supplied in the raw material container by the heating means;
An ion source apparatus comprising: a pressure holding unit capable of holding the pressure in the raw material container at a pressure higher than a pressure at which the raw material is liquefied. The raw material is aluminum chloride,
The ion source apparatus according to claim 1, wherein the pressure holding unit holds the pressure in the raw material container at a pressure of 2 atmospheres or more. A pipe for connecting the raw material container and the chamber and supplying the raw material vapor generated in the raw material container to the chamber;
3. The ion source according to claim 1, wherein the pressure holding unit is a flow resistance unit that is provided inside the pipe and functions as a resistance when steam of the raw material flows down the pipe. apparatus. The flow-down resistance means is a partition member that partitions the pipe into a container side connection part connected to the raw material container and a generation means side connection part connected to the chamber,
The ion source device according to claim 3, wherein the partition member is formed with a communication hole that communicates the container side connection portion and the generation means side connection portion. The pressure holding means is a pipe that connects the raw material container and the chamber, and supplies the raw material vapor generated in the raw material container to the chamber,
The pipe is formed such that an inner diameter R1 of a container side connecting portion connected to the raw material container is smaller than an inner diameter R2 of a generating means side connecting portion connected to the ion generating means (R1 <R2). The ion source device according to claim 1 or 2.   The ion source apparatus according to claim 1, further comprising a pressurized gas supply unit that supplies the raw material container with a pressurized gas that pressurizes the inside of the raw material container. The ion source device according to any one of claims 1 to 6,
An ion implantation apparatus comprising: an implantation unit that implants ions generated by an ion generation unit of the ion source device into an object to be implanted. A steam generating step of heating the raw material in a solid state contained in the raw material container to generate the steam of the raw material;
An ion generation step of generating ions from the raw material vapor generated in the vapor generation step,
In the steam generation step, the raw material is heated in a state where the pressure in the raw material container can be maintained at a pressure equal to or higher than the pressure at which the raw material is liquefied. The solid state raw material accommodated in the raw material container is aluminum chloride,
9. The ion generation method according to claim 8, wherein, in the vapor generation step, the raw material is heated in a state in which the pressure in the raw material container can be maintained at a pressure of 2 atm or more.   An ion implantation method comprising: generating ions by the ion generation method according to claim 8 or 9; and implanting the generated ions into an object to be implanted.

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