JP2013004272A - Ion source and ion implantation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ion source in which less filament (cathode) disconnection occurs and larger-scale and higher-current ion beam is stably generated, compared to a conventional ion source.SOLUTION: An ion source 8 comprises: a plurality of plasma generation containers U11 to U42, each of which has a slit opening part 11 and at least one cathode 2 arranged at such a position that the tip end portion of the cathode 2 protruded inward does not contact a plasma 3; magnetic field generation means 12 for generating a magnetic field in each of the plasma generation containers U11 to U42 along the longer-side direction of the slit opening part 11; and an extraction electrode 6 for drawing out a ribbon-shaped ion beam 19 of which cross section having a substantially rectangular shape, through the slit opening part 11. Regarding the ribbon-shaped ion beams 19 drawn out from the respective plasma generation containers U11 to U42, when viewed from a shorter-side direction of the substantially rectangular cross-sectional surfaces, one end portions in a longer-side direction of the substantially rectangular cross-sectional surfaces overlap with each other.

Description

  The present invention relates to an ion source that generates a ribbon-like (long) ion beam and an ion implantation apparatus including the ion source.

  The size of substrates (silicon wafers, glass substrates, etc.) into which ions are implanted has been increasing year by year. In order to cope with such an increase in the size of the substrate, it has been studied to increase the size of the ion beam applied to the substrate.

  As one method for increasing the size of an ion beam irradiated on a substrate, it is considered to increase the size of an ion source that generates the ion beam. As this type of ion source, a so-called bucket ion source including a plurality of permanent magnets and a plurality of filaments that generate a cusp magnetic field as described in Patent Document 1 has been used.

JP 2000-315473 A (FIG. 1)

  In the bucket ion source described in Patent Document 1, an ionized gas for generating an ion beam introduced into the plasma generation container collides with electrons emitted from a plurality of filaments arranged in the plasma generation container, Plasma is generated. The ion beam is extracted from the plasma by a plurality of electrodes constituting an extraction electrode system arranged adjacent to the opening of the plasma generation container.

  In this type of ion source, a part (tip portion) of a filament is arranged in plasma generated in a plasma generation container. The filament placed in the plasma for a long time is sputtered by ions in the plasma and rapidly thins. In that case, electrons cannot be stably supplied, and the generation efficiency of plasma generated in the plasma generation container is adversely affected. In general, it is desired to stably supply an ion beam from an ion source for a long time. However, if the filament is suddenly thinned by sputtering as described above, the problem that the stable supply of the ion beam cannot be performed. was there.

  Further, when the time required for the ion implantation process is shortened or when a large amount of ions called so-called high dose implantation is implanted, the beam current amount of the ion beam generated by the ion source is increased (large ion beam size). Current) is required.

  In order to realize such a large current, for example, it is conceivable to increase the amount of electrons emitted from the filament and to thicken the generated plasma. However, an increase in the amount of electron emission means that the amount of current flowing through the filament is increased and the filament is heated to a higher temperature. Therefore, evaporation due to heating of the filament proceeds and the filament becomes thin.

  In the ion source of Patent Document 1, when the amount of current flowing to the filament is increased to increase the current of the ion beam, the above-described sputtering action of the filament by plasma and the evaporation action of the filament by high temperature are combined. There is a risk that the filament will be consumed in a short time. If the filament breaks due to exhaustion of the filament, the ion source must be stopped and maintenance must be performed, so that the moving efficiency of the apparatus is deteriorated.

  In view of such circumstances, in the present invention, an ion source capable of stably generating a large and large current ion beam with less filament (cathode) disconnection compared to a conventional ion source and the ion source It is an object of the present invention to provide an ion implantation apparatus including

  An ion source according to the present invention includes a plurality of plasma generation containers, at least one cathode provided in each plasma generation container, and disposed at a position where a tip portion protruding into the plasma generation container does not contact plasma, A gas flow rate controller that is connected to the plasma generation container and individually adjusts the flow rate of ionized gas introduced into each plasma generation container, a slit-shaped opening formed in each plasma generation container, and the slit-shaped opening Accordingly, an extraction electrode for extracting a ribbon-shaped ion beam having a substantially rectangular cross section in a plane perpendicular to the extraction direction, and a magnetic field is generated in each plasma generation container along the longitudinal direction of the slit-shaped opening. An ion source including a magnetic field generation unit, wherein the ribbon-like ion beam drawn from each plasma generation container When viewed al, it is characterized in that at least one end portion is configured to overlap each other in the longitudinal direction of the cross section.

  Since the tip of the cathode is disposed at a position where it does not come into contact with the plasma, the sputtering of the cathode by the plasma is greatly reduced. Therefore, the possibility that the cathode is disconnected is low, and an ion beam can be generated stably for a long time. Further, even if the amount of current flowing to the cathode increases with the increase in current, the influence of the sputtering action by plasma is small, so that the problem that the cathode is consumed in a very short time does not occur. Further, when a ribbon-like ion beam having a substantially rectangular cross section in a plane perpendicular to the extraction direction is extracted from a plurality of plasma generation containers and viewed from the short direction of the cross section, at least one of the longitudinal directions Since the end portions are configured to overlap each other, it is possible to cope with a large substrate in the same manner as in the conventional case.

  In order to improve the plasma generation efficiency in the plasma generation container, it is desirable that a reflective electrode disposed opposite to the cathode is provided in the plasma generation container in the longitudinal direction of the slit-shaped opening.

  A plurality of the magnetic field generating means may be provided, and the magnetic field may be generated independently for each predetermined number of plasma generation containers.

  On the other hand, the magnetic field generation means may generate a common magnetic field inside each plasma generation container. In this case, since only one magnetic field generating means is required, there is an advantage that maintenance is simplified accordingly.

  An ion implantation apparatus according to the present invention is an ion implantation apparatus including the above-described ion source, and the ion implantation apparatus includes a processing chamber into which a ribbon-like ion beam drawn from each plasma generation container is introduced, A substrate drive mechanism for moving the substrate in a direction intersecting the ribbon-like ion beam so that an ion implantation process is performed on the entire surface of the substrate irradiated with the ribbon-like ion beam in the processing chamber; It is characterized by having.

  On the other hand, another ion implantation apparatus according to the present invention is an ion implantation apparatus including the above-described ion source, and the ion implantation apparatus performs mass analysis of a ribbon-like ion beam drawn from each plasma generation container. An analysis electromagnet that performs the analysis, an analysis slit that passes only the ion beam containing the desired ions out of the ribbon ion beam that has passed through the analysis electromagnet, and a ribbon ion beam drawn from each plasma generation vessel are introduced. The substrate is moved in a direction intersecting the ribbon-shaped ion beam so that ion implantation processing is performed on the entire surface of the processing chamber and the substrate irradiated with the ribbon-shaped ion beam. And a substrate driving mechanism.

  With such an ion implantation apparatus, the substrate can be irradiated with only an ion beam containing a desired ion species by performing mass analysis of the ion beam with an analysis electromagnet.

  The analysis electromagnet has a plurality of magnetic pole pairs arranged to face each other so as to sandwich the ribbon-like ion beam drawn from each plasma generation vessel from its long side direction, and is drawn from each plasma generation vessel. It is desirable that the distance between the magnetic poles constituting each magnetic pole pair is increased as the distance that the ribbon-like ion beam passes through the analysis electromagnet becomes longer.

  The ribbon-like ion beam drawn from each plasma generation container has a different path through the analysis electromagnet. The longer the distance that passes through the analysis electromagnet, the greater the amount of deflection of the ribbon-like ion beam. Then, after passing through the analysis electromagnet, there is a possibility that the beam paths of the ribbon-like ion beams drawn out from the respective plasma generation containers intersect each other. In addition, if the irradiation angle of each ribbon-like ion beam to the substrate is excessively different, the characteristics of devices manufactured on the substrate are adversely affected. On the other hand, as described above, the distance between the magnetic poles constituting each magnetic pole pair increases as the distance that the ribbon-like ion beam drawn from each plasma generation container passes through the analysis electromagnet becomes longer. Therefore, it can be expected that the crossing of the beam paths described above is prevented, and the adverse effect on the characteristics of the device manufactured on the substrate is prevented.

  Furthermore, it is desirable that a conductive member for separating the path through which the ribbon-like ion beam drawn from each plasma generation vessel passes is disposed in the path to the ion source and the processing chamber. .

  When such a conductive member is used, it is confirmed that the fluctuation of the spatial potential due to the space charge effect generated around one ion beam passing through the adjacent beam path affects the other ion beam. Can be prevented.

  The ion implantation apparatus preferably includes a beam current measuring device for measuring a beam current density distribution of each ion beam in the processing chamber.

  If such a beam current measuring device is provided, the measurement result is monitored, and the operator of the ion implantation apparatus changes various parameters of the ion implantation apparatus, and the beam of each ribbon-like ion beam irradiated on the substrate. Work such as adjusting the current density distribution can be performed.

  Further, according to the measurement result of the beam current measuring device, it is determined whether or not the distribution obtained by combining the beam current density distributions of the respective ribbon-like ion beams is within a desired range. It is desirable to provide a control device having a function of adjusting the operating parameters of the ion source when it is determined that

  If such a control device is provided, the beam current density distribution can be automatically adjusted to a target value.

  Compared to a conventional ion source, the filament (cathode) is less disconnected, and a large and large current ion beam can be generated stably.

The sectional view of the plasma generation container used with one ion source concerning the present invention is expressed. The state when the plasma production container of FIG. 1 is seen from the Z direction opposite side is represented. An example of the magnetic field production | generation means used with the ion source which concerns on this invention is represented. Another example of the magnetic field generation means used in the ion source according to the present invention is shown. The example of the extraction electrode used with the ion source which concerns on this invention is represented. (A) is an example of an extraction electrode having a common extraction opening for a plurality of plasma generation containers, and (B) is an example of an extraction electrode having individual extraction openings for a plurality of plasma generation containers. . An arrangement example of a plasma generation container used in an ion source according to the present invention is shown. (A) is an arrangement example of a plurality of plasma generation containers in which the positions in the X direction are staggered along the Y direction. (B) is a modification of the arrangement example shown in (A). Is an example in which plasma generation containers are irregularly arranged along the Y direction. Sectional drawing of the plasma production container used with the other ion source which concerns on this invention is represented. The top view of the one ion implantation apparatus which concerns on this invention is represented. An example of the beam current measuring device used with the ion implantation apparatus which concerns on this invention is represented. It is explanatory drawing which concerns on adjustment of the beam current density distribution measured with the beam current measuring device. (A) represents the beam current density distribution before adjustment, and (B) represents the beam current density distribution after adjustment. An example of the analysis electromagnet used with the ion implantation apparatus which concerns on this invention is represented. (A) represents the state when the inside of the analysis electromagnet is viewed from the Z direction, and (B) represents the state when the analysis electromagnet is viewed from the X direction. An example of the shielding means used with the ion implantation apparatus which concerns on this invention is represented. (A) represents a state when the shielding unit is viewed from the Z direction, and (B) represents a state when the shielding unit is viewed from the Y direction. An example of the board | substrate drive mechanism used with the ion implantation apparatus which concerns on this invention is represented. The ion implantation apparatus which concerns on this invention represents a mode that an ion beam is irradiated on a board | substrate. The top view of the other ion implantation apparatus which concerns on this invention is represented.

  FIG. 1 shows a cross-sectional view of a plasma generation vessel 1 constituting one ion source according to the present invention. The X direction, the Y direction, and the Z direction are orthogonal to each other at one point, and the Z direction is a direction in which an ion beam 19 described later is extracted from the plasma generation container 1.

  A gas supply path 5 is connected to the wall surface of the plasma generation container 1. A gas source 6 is attached to the gas supply path 5 via a valve 9, and an ionized gas as a raw material for the ion beam 19 is supplied from the gas source 6. The gas supply path 5 is provided with a gas flow rate regulator 7 (mass flow controller), which adjusts the supply amount of ionized gas from the gas source 6 into the plasma generation vessel 1.

A U-shaped filament 2 is attached to one side surface of the plasma generation container 1 via an insulator 10. Between the filament 2 terminals are connected filament power supply V _F is configured to allow adjustment of the amount of current flowing through the filament 2. The filament power supply V _F is connected to the plasma generating vessel 1 through the arc power source V _A.

By passing an electric current through the filament 2 and heating the filament 2, electrons are emitted therefrom. Inside the plasma generation vessel 1, a magnetic field B is generated in the direction of the arrow shown inside the plasma generation vessel 1 by a magnetic field generation means 12, which will be described later, and emitted from the filament 2 along this magnetic field B. Electrons move. The electrons collide with ionized gas (PH ₃ , BF _3, etc.) supplied into the plasma generation container 1 to cause ionization of the ionized gas, and plasma 3 is generated in the plasma generation container 1.

  The filament 2 of the present invention is arranged at a position where the tip portion located in the X direction does not contact the plasma 3. For this reason, sputtering of the filament 2 by the plasma 3 can be reduced. Here, only one filament 2 is depicted, but a plurality of filaments 2 may be arranged as in the prior art.

A reflective electrode 4 is provided inside the plasma generation container 1 at a position facing the filament 2. The reflective electrode 4 is attached to the plasma generating vessel 1 through an insulator 10, and the plasma generating chamber 1 to a reference potential, the power supply V _B is connected to a negative potential. Thus, by setting the potential of the reflective electrode 4 to a negative potential, when the electrons emitted from the filament 2 move to the reflective electrode 4 side by the magnetic field B, it can be reflected to the opposite side. As a result, the collision probability between the ionized gas and the electrons is improved, and the generation efficiency of the plasma 3 can be increased. The reflective electrode 4 is for improving the generation efficiency of the plasma 3 and is not necessarily provided.

Further, here, the potential of the reflective electrode 6 is configured such that the negative potential with the power V _B, without using such a power supply may be set to the floating potential. In that case, the electrons emitted from the filament 2 collide with the reflective electrode 6, whereby the reflective electrode 6 is negatively charged, and finally the electrons can be reflected to the filament 2 side. Although not shown, a reflective electrode may also be provided on the back side of the filament 2.

  FIG. 2 shows a state of the plasma generation container 1 when FIG. 1 is viewed from the opposite side in the Z direction. As shown in FIG. 2, a slit-like opening 11 is formed on the side surface of the plasma generating vessel 1 located on the Z direction side, and through this, an ion beam is extracted using an extraction electrode 16 described later. 19 withdrawals are made.

  In the present invention, the ion source 8 is constituted by the plurality of plasma generation containers 1. As an example, FIG. 3 discloses an example including four plasma generation containers (U11, U12, U21, U22) arranged approximately in a matrix. In addition, the structure of each plasma production container (U11, U12, U21, U22) is the same structure as the plasma production container 1 demonstrated in FIG.

  As described with reference to FIG. 1, the ion source 8 of the present invention is provided with the magnetic field generation means 12 for generating the magnetic field B inside the plasma generation container 1. In the example of FIG. 3, the example of the magnetic field production | generation means 12 which produces | generates the magnetic field B common to the inside with respect to all the four plasma production | generation containers (U11, U12, U21, U22) is disclosed.

  The magnetic field generation means 12 depicted in FIG. 3 includes a substantially square-shaped yoke 13 in which each plasma generation container (U11, U12, U21, U22) is disposed, and the yoke 13 along the X direction. 13 is provided with a pair of magnetic poles 14 that protrude in the inner region (region on the side where each plasma generation container is disposed) and are arranged to face each other. A coil 15 is wound around each magnetic pole 14, and each coil 15 is connected to a power source (not shown).

  For example, when a current is passed through each coil 15 such that the magnetic pole 14 located on the upper side of the paper is an N pole and the magnetic pole 14 located on the lower side of the paper is an S pole, as shown in FIG. A magnetic field B common to the inner region of U12, U21, U22) is generated.

 In the example of FIG. 3, the magnetic field B common to the inner regions of the plasma generation containers (U11, U12, U21, U22) is generated using one magnetic field generation means 12, but instead of this, the magnetic field B of FIG. As described above, a plurality of magnetic field generation means 12 may be provided. In the example of FIG. 4, the magnetic field generating means 12 is individually provided for a set including the plasma generation containers U11 and U12 and a set including the plasma generation containers U21 and U22. Since the configuration of each magnetic field generation unit 12 is the same as that described in the above example, a detailed description thereof will be omitted, but here, each magnetic field generation unit 12 applies each plasma generation container set to each plasma generation container set. It becomes possible to generate a magnetic field independently. In the example of FIG. 4, the magnetic field B1 is generated for the pair of plasma generation containers U11 and U12, whereas the magnetic field B2 is generated for the pair of plasma generation containers U21 and U22. The magnetic field generated for each plasma generation container set may be the same.

  In the example of FIG. 4, the configuration is such that two plasma generation containers are paired and one magnetic field generation means 12 is associated therewith. However, one magnetic field generation means 12 is associated with each plasma generation container. May be. Furthermore, one set may be configured by two plasma generation containers, and another set may be configured by three plasma generation containers. In that case, as in the previous example, one magnetic field generating means 12 is provided for each group. Here, although an electromagnet is used as the magnetic field generation means 12, a permanent magnet may be used instead. In that case, two permanent magnets may be prepared and attached to the respective magnetic poles 14 so that different polarities are opposed to each other in the X direction.

  The ion source 8 of the present invention is provided with an extraction electrode 16 for extracting the ion beam 19 from the plasma generation container 1. The configuration of the extraction electrode 16 will be described with reference to FIG. 5A and 5B, four plasma generation containers (U11, U12, U21, U22) cited as an example in FIGS. 3 and 4 and the front (Z direction side) thereof are arranged. An extraction electrode 16 is depicted. In this figure, each plasma generation container (U11, U12, U21, U22) and the slit-shaped opening 11 formed in the plasma generation container are drawn by broken lines.

  In this example, an ion beam having a positive charge is assumed as the extracted ion beam. Therefore, a power supply (not shown) is connected to the extraction electrode 16 so that the potential of the extraction electrode 16 becomes a negative potential with reference to each plasma generation container (U11, U12, U21, U22). The configuration of the extraction electrode 16 will be specifically described. In the example of FIG. 5A, two extraction openings 17 are formed in one large extraction electrode 16. Each drawer opening 17 is individually provided for a set including the plasma generation container U11 and the plasma generation container U12 and a set including the plasma generation container U21 and the plasma generation container U22.

  In FIG. 5A, one drawer opening 17 is arranged for two plasma generation containers, but instead of this, as shown in FIG. On the other hand, the drawer opening 17 may be provided individually. Although not shown here, the ion beam 19 extracted through the extraction opening 17 of the extraction electrode 16 is a ribbon having a substantially rectangular cross section in a plane perpendicular to the extraction direction (Z direction). In the form of ion beam.

  3-5, the example which has arrange | positioned four plasma production | generation containers was given, However, The arrangement | positioning of the plasma production | generation container of this invention is not restricted to this. 6A to 6C show arrangement examples of plasma generation containers constituting the ion source 8 of the present invention.

  In the present invention, the ribbon-like ion beam drawn from each plasma generation container is cut along a plane perpendicular to the drawing direction, and each ribbon-like shape is cut from the short side of the cut surface at a substantially rectangular cut surface at that time. When the ion beam is viewed, at least one end in the longitudinal direction of the cut surface is overlapped with each other. With such a configuration, even when the substrate size becomes large, the ion implantation process can be performed without any problem as in the conventional case. The substantially rectangular cross section of the ribbon-like ion beam 19 extracted by the extraction electrode 16 is substantially equal to the shape of the slit-shaped opening 11 formed in each plasma generation container. Therefore, as shown in FIGS. 6A to 6C, each plasma generation container can be arranged.

  More specifically, in FIG. 6 (A), in the Y direction, a pair of plasma generation containers (a group consisting of U11 and U12, a group consisting of U31 and U32) and an even number are arranged in the Y direction. The positions in the X direction of the plasma generation container groups (the group consisting of U21 and U22, the group consisting of U41 and U42) are different. The positions of the odd-numbered plasma generation container groups and the even-numbered plasma generation container groups in the X direction are in the Y direction (roughly rectangular when a ribbon-like ion beam is cut along a plane perpendicular to the extraction direction). In the X direction of the slit-shaped opening 11 formed in the adjacent plasma generation container (corresponding to the short direction of the cut surface of the ribbon) when the ribbon-like ion beam is cut along a plane perpendicular to the extraction direction. Are arranged so that at least one end thereof overlaps each other. With such an arrangement, when the ribbon-like ion beam 19 drawn from each plasma generation container is viewed from the short direction of the substantially rectangular cross section, at least one end in the longitudinal direction of the substantially rectangular cross section Can be configured to overlap each other.

  FIG. 6A shows an example in which the odd-numbered plasma generation container group and the even-numbered plasma generation container group are arranged at different positions in the X direction. This is shown in FIG. 6B. As shown, it may be deformed. In FIG. 6B, the first and fourth plasma generation container groups (the group consisting of U11 and U12, the group consisting of U41 and U42) and the second and third positions are arranged along the Y direction. The plasma generation container group (a group composed of U21 and U22, a group composed of U31 and U32) is arranged so that the positions in the X direction are different. Even if it does in this way, there can exist an effect similar to the example shown in FIG. 6 (A).

  Further, as shown in FIG. 6C, the configuration of each plasma generation container set arranged in the Y direction may be changed. Here, the number of plasma generation containers arranged first and second in the Y direction is one, and the number of plasma generation containers arranged third is two. Even in such a configuration, the X-direction of the slit-shaped opening 11 formed in each plasma generation container (U11, U21, U31, U32) (ribbon-shaped ion beam was cut along a plane perpendicular to the extraction direction) At least one end of the substantially rectangular cut surface at the time is a short of the substantially rectangular cut surface when the ribbon-shaped ion beam is cut along a plane perpendicular to the extraction direction. If they are arranged so as to overlap when viewed from the (corresponding to the hand direction), the same effects as those shown in FIGS. 6A and 6B can be obtained. Of course, the number of plasma generation containers is not limited to that shown here. The number of plasma generation containers may be two or more.

The configuration of the plasma generation vessel 1 shown in FIG. 7 is different from that shown in FIG. 1 in the cathode portion. In the example of FIG. 7, the cathode that emits electrons is constituted by the indirectly heated cathode 18. This configuration is known as an indirectly heated ion source. Flowing a current to the filament 2 by filament power supply V _F, it emits electrons by heating a filament 2. The filaments 2 to the reference potential, the cathode power source V _C so that the potential of the indirectly heated cathode 18 becomes the positive potential than it is connected. By this cathode power source V _C , electrons emitted from the filament 2 are attracted to the indirectly heated cathode 18 and knocked there. When the electrons are struck by the indirectly heated cathode 18, the indirectly heated cathode 18 is heated, and when heated to a certain temperature, the electrons are emitted from the indirectly heated cathode 18. Since the mechanism for generating the plasma 3 is the same as that in the example of FIG. 1, the description thereof is omitted here. However, such a indirectly heated cathode 18 may be used as a cathode for emitting electrons. good. In addition, the inside of the plasma generation container as used in the field of this invention means the area | region also including the opening part in which the indirectly heated cathode 18 formed in the plasma generation container is arrange | positioned.

  FIG. 8 shows an example of an ion implantation apparatus IM according to the present invention. Here, in order to simplify the illustration of the ion source 8, the magnetic field generating means 12, the extraction electrode 16 and the like described so far are omitted. In addition, in order to simplify the following description, the configuration of the plurality of plasma generation containers includes two plasma generation containers among the four plasma generation containers (U11, U12, U21, U22) shown in FIG. A configuration provided with (U11 and U21) is taken as an example.

  The ion beam 19 extracted from each plasma generation container (U11, U21) contains things other than the desired ion species. Therefore, mass spectrometry is performed using the analysis electromagnet 20 and the analysis slit 21 as conventionally known in order to irradiate the substrate 23 with only the desired ion species. The ion beam 19 subjected to mass analysis is irradiated to a beam current measuring instrument 25 disposed in the processing chamber 22. The beam current measuring device 25 measures the beam current density distribution along the X direction as will be described later, and the measurement result is transmitted to the control device 26 as a signal S9. When it is determined that the beam current density distribution is within a desired range, the control device 26 transmits a control signal S7 to the substrate driving mechanism 24 that supports the substrate 23. The substrate driving mechanism 24 that has received the control signal S7 uses the two ion beams 19 to cross the ion beam 19 so that the entire surface of the substrate 23 is irradiated with the ion beam 19 (here, Y Direction).

On the other hand, when it is determined that the beam current density distribution is out of the predetermined range, the control device 26 transmits control signals S1 to S4 to the ion source 8, and the filament power supply V _F provided in the ion source 8; The operating parameter values of the ion source such as the arc power source V _A , the mass flow controller 7 and the cathode power source V _C are adjusted. Further, in addition to the adjustment of the operation parameters, a shielding means 27 for partially shielding each ion beam 19 is provided on the downstream side (processing chamber 22 side) of the analysis slit 21, and the beam current density is used by using this. The distribution may be adjusted. The shielding means 27 is controlled by a control signal S6 from the control device 26, and the amount of movement in the direction of the arrow shown is adjusted. In addition, when the beam current density distribution is adjusted, the beam current density distribution is monitored by the beam current measuring device 25.

  The path of the ion beam 19 extracted from each plasma generation container (U11, U21) is electrically isolated from the ion source 8 to the processing chamber 22 by a conductive member 31 having a mesh-shaped hole. Further, the conductive member 31 is made of, for example, carbon that is a non-magnetic material and is electrically grounded. When the beam paths of the two ion beams 19 are separated from each other by such a conductive member 31, the spatial potential fluctuation generated around one ion beam 19 due to the space charge effect is The influence on the other ion beam 19 can be prevented. In addition, since each ion beam has a positive charge, they repel each other if they are too close. However, if such a conductive member 31 is provided, the two ion beams 19 can be disposed close to each other because of potential separation, and the ion implantation apparatus IM can be downsized and the substrate can be driven. The drive range of the substrate 23 when the ion implantation process is performed on the entire surface of the substrate 23 using the mechanism 24 can be narrowed.

  Each part constituting the ion implantation apparatus IM will be described below. FIG. 9 illustrates an example of the beam current measuring instrument 25. In the beam current measuring instrument 25, for example, a plurality of Faraday cups 40 that are long in the Y direction are arranged along the X direction. The Faraday cup 40 is large enough to cover the two ion beams 19 drawn from the plasma generation containers (U11, U21) in the Y direction, and covers one end to the other end of the two ion beams 19 in the X direction. A plurality are arranged.

  The measurement result of the beam current measuring instrument 25 is drawn on the right side of the page of the beam current measuring instrument 25 shown in FIG. In this measurement result, the vertical axis represents the position on the beam current measuring instrument 25, and the horizontal axis represents the magnitude of the beam current density. When attention is paid to the beam current density distribution of each ion beam 19, the beam current density in the vicinity of the central portion of the ion beam 19 is large and becomes a gentle distribution toward the end portion. In this example, the ends in the X direction of the ion beams 19 drawn from the plasma generation container U11 and the plasma generation container U21 overlap when viewed from the Y direction. This overlapping portion is located in a region indicated as A in the measurement result, and in this region, the beam current density distribution by each ion beam 19 is gradually decreased as shown by a broken line. The current density of each ion beam 19 is superimposed, and a beam current density distribution as indicated by a solid line is measured.

  A method for obtaining a desired beam current density distribution will be briefly described with reference to FIGS. 10 (A) and 10 (B). In FIG. 10A, the beam current density distribution measured by the beam current measuring device 25 is drawn. Here, it is assumed that ion implantation into the substrate 23 is performed using an ion beam 19 having a beam current density value of H ± α and a width in the X direction of W.

In this case, in the regions C and D shown in the figure, the value of the beam current density exceeds the range of H + α. Therefore, the beam current density in this region must be reduced. In this case, for example, by the control device 26, the filament power supply V _F is controlled, the amount of current flowing through the filament 2 is reduced. When the amount of current decreases, the concentration of the plasma 3 decreases, so that the amount of the ion beam 19 drawn from the plasma generation container 1 decreases. As a result, as shown in FIG. 10B, the beam current density distribution decreases as a whole and satisfies a predetermined range.

Here it has been described a control example for adjusting the filament power supply V _F, other in, so as to control the gas flow rate, etc. to be introduced into the arc power supply V _C and the plasma generating chamber provided in the ion source 8 described above May be. In addition, it is conceivable that the control target is determined in advance, the order is stored in the control device 26, and the control target is controlled according to a predetermined order. In this case, the control order may be determined by the difference between the desired range and the measured beam current density distribution. For example, if the difference is large, adjust the parameters suitable for coarse adjustment (parameters that greatly vary the beam current density distribution with a little adjustment), and if the difference decreases, make fine adjustments. The order of the operation parameters to be adjusted may be determined by adjusting suitable parameters (parameters in which the beam current density distribution hardly fluctuates even if the adjustment amount is large).

  On the other hand, the operator (operator) of the ion implantation apparatus IM may be manually adjusted without providing the control device 26. In that case, a monitor for displaying the measurement result by the beam current measuring instrument 25 is prepared, and the operator can adjust the measured beam current density distribution so that the measured beam current density distribution falls within a desired range while viewing this monitor. It is conceivable to configure it.

  Further, the configuration of the beam current measuring device 25 is not a configuration in which a plurality of ion beams 19 are measured at once, but individually for each ion beam 19 so that each ion beam 19 can be measured individually. A beam current measuring device 25 may be provided. In that case, the measurement results may be added later.

  FIG. 11A and FIG. 11B are examples of the analyzing electromagnet 20 shown in FIG. FIG. 11A shows a cross-sectional state of the analysis electromagnet 20. The analyzing electromagnet 20 includes a yoke 28, and the yoke 28 is provided with a first magnetic pole pair 29 and a second magnetic pole pair 30 having different distances (gap) between the magnetic poles in the X direction. In the Y direction, the coil 15 is wound so as to cover both magnetic poles of the first magnetic pole pair 29 and the second magnetic pole pair 30 that are arranged to face each other in the X direction. In this example, the coil 15 is arranged on the upper side of the drawing. A magnetic field is generated toward each magnetic pole pair arranged on the lower side of the drawing with respect to each magnetic pole pair. The first magnetic pole pair 29 and the second magnetic pole pair 30 are configured such that the distance between the magnetic poles can be changed independently by a magnetic pole driving mechanism 39 made of a motor or the like.

  The ion beam 19 extracted from the plasma generation container U11 illustrated in FIG. 8 passes between the first magnetic pole pairs 29, and similarly, the plasma generation illustrated in FIG. 8 is performed between the second magnetic pole pairs 30. The ion beam 19 extracted from the container U21 passes. In addition, in the Y direction, a conductive member 31 is provided so as to separate the beam paths of the ion beams 19 in terms of potential.

  The turning radius of the ion beam 19 extracted from each plasma generation container (U11, U21) is the same as the turning radius of the analysis electromagnet 20 when the desired ion species and the energy of the ion beam are the same. Although depending on the distance between the analysis electromagnet 20 and the substrate 23, etc., if the turning radii are the same, the paths of the ion beams 19 may cross each other. In addition, when the difference in the incident angle of each ion beam 19 onto the substrate 23 increases, the characteristics of devices manufactured on the substrate vary greatly depending on the location. For this reason, it is desirable to adjust the trajectories of both ion beams 19 to be as parallel as possible by making the turning radii of the ion beams 19 drawn from the plasma generation containers (U11, U21) different.

  In the case of FIG. 8, since each ion beam 19 is swung clockwise by the analysis electromagnet 20, the ion beam 19 swung outward (located on the Y direction side in FIG. 11A) (extracted from the plasma generation vessel U11). It is necessary to make the turning radius of the ion beam 19) larger than the turning radius of the other ion beam 19 (ion beam 19 extracted from the plasma generation container U21) turning inside. When the ion species and energy of the ion beam 19 are the same, the turning radius varies depending on the strength of the magnetic field for turning the ion beam 19. Since the strength of the magnetic field becomes weaker as the distance between the magnetic poles increases, the distance between the magnetic poles of the first magnetic pole pair 29 is made wider than the distance between the magnetic poles of the second magnetic pole pair 30 in this example. The magnitude relationship between the magnetic pole distances is as described above. How to set the interval between the magnetic pole distances depends on the distance between the analysis electromagnet 20 and the substrate 23, the device manufactured on the substrate 23, and the like. It is appropriately set according to various conditions such as characteristics.

  Thus, by making the distance between the magnetic poles different, the first magnetic field B1 generated in the first magnetic pole pair 29 can be made weaker than the second magnetic field B2 generated in the second magnetic pole pair 30, Depending on the setting of the distance between the magnetic poles, the beam paths of the ion beams 19 can be made substantially parallel. Here, in the analysis electromagnet 20, in order to make the turning radius of the ion beam 19 turning outwardly larger than the turning radius of the other ion beam 19 turning inside, the magnetic pole through which the ion beam 19 turning outward passes. The expression that the distance between them is wider than the distance between the magnetic poles through which the other ion beam 19 passes is used. In other words, the expression can be expressed as follows. The distance between the magnetic poles formed on the analysis electromagnet 20 increases as the distance that the ion beam passes through the analysis electromagnet 20 increases. That is, in the analysis electromagnet 20, the distance that passes through the analysis electromagnet 20 becomes longer as the ion beam 19 passes outside. On the contrary, the ion beam 19 passing through the inside of the analysis electromagnet 20 has a shorter distance to pass through the analysis electromagnet 20. Therefore, the expression of the distance that the ion beam 19 passes through the analysis electromagnet 20 can be used instead of the expression of inside and outside.

  The widths of the magnetic pole 29 and the magnetic pole 30 in the Y direction are sufficiently wider than the dimensions of the ion beam 19 passing therethrough in the same direction. Further, it is desirable that the ion beam 19 passing between the magnetic poles is configured to pass through the central portion of each magnetic pole in the Y direction. This is because at the magnetic pole ends arranged between the magnetic poles adjacent in the Y direction, the magnetic fields interfere with each other and the magnetic field distribution is distorted, which may hinder mass analysis of the ion beam 19. . For this reason, it is desirable to set the size of the magnetic pole and the passage position of the ion beam that passes between the magnetic poles as described above.

  FIG. 11B shows a state when the analyzing electromagnet 20 is viewed from the X direction. In this figure, the alternate long and short dash line in the inner region of the analysis electromagnet 20 represents the outer shape of the first magnetic pole pair 29 and the second magnetic pole pair 30, and the solid line represents the trajectory of the desired ion beam 19. A broken line represents the conductive member 31. As can be understood from this figure, the width of the first magnetic pole pair 29 and the width of the second magnetic pole pair 30 are the same along the beam path of the ion beam 19. Note that the X-axis, Y-axis, and Z-axis shown in FIG. 11B indicate directions at the outlet of the analysis electromagnet 20 (on the right side in the drawing), and inside the analysis electromagnet 20 except for the X-axis direction. These directions are appropriately changed.

  12A and 12B show an example of the shielding means 27 shown in FIG. As shown here, for example, the shielding means 27 is individually provided for the ion beam 19 extracted from each plasma generation container (U11, U21). The shielding means 27 includes a pair of shielding members 34 arranged so as to sandwich each ion beam 19 from the short side direction (Y direction). The shielding members 34 forming a pair are long sides of the ion beam 19. A plurality are arranged along the direction (X direction).

  Support shafts 33 are connected to the individual shielding members 34, and the support shafts 33 are independently moved in the directions of the arrows shown by the shielding member driving mechanism 32, so that one of the ion beams 19 can be moved. The beam current density distribution is adjusted by shielding the part. As the shielding member driving mechanism 32, for example, a mechanism having a plurality of motors as a power source and configured to individually drive the individual support shafts 33 is conceivable.

  FIG. 12B illustrates a state when the shielding unit 27 is viewed from the Y direction. As illustrated in this drawing, the plurality of shielding members 34 are arranged in a staggered manner along the X direction so that the positions in the Z direction are alternately different. With this arrangement, the current density distribution of the ion beam 19 can be adjusted seamlessly over the entire X direction.

  FIG. 13 illustrates an example of the substrate driving mechanism 24 illustrated in FIG. The substrate drive mechanism 24 includes a substrate holder 38 that supports the substrate 23, and includes a lower end surface (an end surface located on the X direction side) of the substrate holder 38 and a lower end portion that extends from the lower end surface along the Z direction. Is supported by four rotating bodies 37. Two rotating bodies 37 that support the lower end surface of the substrate holder 38 are supported by a support shaft 36 attached to a support base 41 disposed on the processing chamber 22 so as to be rotatable in the direction of the arrow shown in the figure. Yes. A rotating body 37 that supports the Z-direction side of the lower end of the substrate holder 38 is supported by a support shaft 36 provided on the processing chamber 22 so as to be rotatable in the direction of the arrow shown in the figure. On the other hand, a rotating body 37 that supports the opposite side of the lower end in the Z direction is fixed to a rotating shaft 43 of a driving source 42 (motor) provided outside the processing chamber 22 via a vacuum seal 35, and is driven. When the rotation shaft 43 is rotated by the source 42, the rotation shaft 43 is integrally rotated with the rotation shaft 43 in the direction indicated by the arrow. Thereby, the substrate holder 38 can be moved in the Y direction. In addition, although illustration is abbreviate | omitted, the support mechanism of the substrate holder 38 which has the above-mentioned four rotary body 37 is provided with two or more along the Y direction.

FIG. 14 illustrates a state in which the ion beam 19 extracted from each plasma generation container (U11, U21) is irradiated onto the substrate 23. Since the substrate 23 is moved along the Y direction in a direction intersecting with the two ion beams 19 (in this example, the Y direction), ion implantation to the entire surface of the substrate 23 is thereby achieved.
<Other variations>

  In the example of FIG. 8, the positions of the plasma generation container U11 and the plasma generation container U21 in the Z direction are the same. In that case, the distance of the beam path until the ion beam 19 extracted from each plasma generation container is irradiated onto the substrate is different. If the distance of the beam path is different, the influence of the space charge effect received by each ion beam 19 is different, so that the shape of the ion beam 19 irradiated on the substrate 23 is different. In the example of FIG. 8, the number of plasma generation containers is two. However, as the number of plasma generation containers arranged in the Y direction increases, the difference in the beam transport distance of each ion beam 19 increases.

  If the shape of the ion beam 19 applied to the substrate 23 is substantially the same, the beam current density distribution of each ion beam 19 can be easily controlled. This is because adjustment of the current density distribution of another ion beam can be expected using the result obtained by adjusting the current density distribution of one ion beam.

  Therefore, as shown in FIG. 15, the positions of the plasma generation containers (U11, U21) in the traveling direction of the ion beam 19 are made different from each plasma generation container (U11, U21) to the substrate 23. The distances L1 and L2 until 19 is irradiated are set to be the same distance. When such a configuration is used, the shape of the ion beam 19 extracted from each plasma generation container (U11, U21) can be made substantially the same at the irradiation position on the substrate 23.

  In addition to the above, it goes without saying that various improvements and modifications may be made without departing from the scope of the present invention.

1, U11, U12, U21, U22, U31, U32, U41, U42 ... Plasma generation vessel 2 ... Filament 3 ... Plasma 7 ... Gas flow rate regulator 8 ... Ion source 11 ... Slit-shaped opening 12 ... Magnetic field generating means 16 ... Extraction electrode 17 ... Extraction opening 19 ... Ion beam 20 ... Analysis electromagnet 21 ... Analysis slit 23 ... Substrate 24 ... -Substrate drive mechanism 31 ... conductive member IM ... ion implantation apparatus

Further, here, the potential of the reflecting electrode 4 are configured such that the negative potential with the power V _B, without using such a power supply may be set to the floating potential. In this case, since the electrons emitted from the filament 2 impinges on the reflective electrode 4, the reflective electrode 4 is negatively charged, and eventually can be reflected electrons to the filament 2 side. Although not shown, a reflective electrode may also be provided on the back side of the filament 2.

FIG. 11A and FIG. 11B are examples of the analyzing electromagnet 20 shown in FIG. FIG. 11A shows a cross-sectional state of the analysis electromagnet 20. The analyzing electromagnet 20 includes a yoke 28, and the yoke 28 is provided with a first magnetic pole pair 29 and a second magnetic pole pair 30 having different distances (gap) between the magnetic poles in the X direction. In the Y direction, the coil 15 is wound so as to cover both of the first magnetic pole pair 29 and the second magnetic pole pair 30 that are opposed to each other in the X direction. In this example, the coil 15 is disposed on the lower side of the drawing. and toward each pole pairs arranged in the plane above side of the pole pair, the magnetic field is generated. The first magnetic pole pair 29 and the second magnetic pole pair 30 are configured such that the distance between the magnetic poles can be changed independently by a magnetic pole driving mechanism 39 made of a motor or the like.

Thus, by making the distance between the magnetic poles different, the first magnetic field B 3 generated in the first magnetic pole pair 29 can be made weaker than the second magnetic field B 4 generated in the second magnetic pole pair 30. Depending on the setting of the distance between the magnetic poles, the beam paths of the ion beams 19 can be made substantially parallel. Here, in the analysis electromagnet 20, in order to make the turning radius of the ion beam 19 turning outwardly larger than the turning radius of the other ion beam 19 turning inside, the magnetic pole through which the ion beam 19 turning outward passes. The expression that the distance between them is wider than the distance between the magnetic poles through which the other ion beam 19 passes is used. In other words, the expression can be expressed as follows. The distance between the magnetic poles formed on the analysis electromagnet 20 increases as the distance that the ion beam passes through the analysis electromagnet 20 increases. That is, in the analysis electromagnet 20, the distance that passes through the analysis electromagnet 20 becomes longer as the ion beam 19 passes outside. On the contrary, the ion beam 19 passing through the inside of the analysis electromagnet 20 has a shorter distance to pass through the analysis electromagnet 20. Therefore, the expression of the distance that the ion beam 19 passes through the analysis electromagnet 20 can be used instead of the expression of inside and outside.

Claims (10)

A plurality of plasma generation vessels;
At least one cathode provided in each plasma generation container and disposed at a position where a tip portion protruding into the plasma generation container does not come into contact with plasma;
A gas flow rate controller that is connected to each plasma generation vessel and individually adjusts the flow rate of ionized gas introduced into each plasma generation vessel;
A slit-shaped opening formed in each plasma generation container;
An extraction electrode for extracting a ribbon-like ion beam having a substantially rectangular cross section in a plane perpendicular to the extraction direction from the slit-shaped opening,
An ion source comprising magnetic field generation means for generating a magnetic field in each plasma generation container along the longitudinal direction of the slit-shaped opening,
When the ribbon-like ion beam drawn from each plasma generation container is viewed from the short direction of the cross section, at least one end in the longitudinal direction of the cross section is configured to overlap each other. Ion source.     The ion source according to claim 1, wherein a reflective electrode disposed opposite to the cathode is provided in the plasma generation container in a longitudinal direction of the slit-shaped opening.   3. The ion source according to claim 1, wherein a plurality of the magnetic field generating means are provided, and the magnetic field is generated independently for each predetermined number of plasma generation containers.   4. The ion source according to claim 1, wherein the magnetic field generating means generates a common magnetic field inside each plasma generation container. An ion implantation apparatus comprising the ion source according to claim 1, 2, 3, or 4.
The ion implantation apparatus includes a processing chamber into which a ribbon-like ion beam drawn from each plasma generation container is introduced;
A substrate drive mechanism for moving the substrate in a direction intersecting the ribbon-like ion beam so that an ion implantation process is performed on the entire surface of the substrate irradiated with the ribbon-like ion beam in the processing chamber; It is characterized by having. An ion implantation apparatus comprising the ion source according to claim 1, 2, 3, or 4.
The ion implantation apparatus includes an analysis electromagnet for performing mass analysis of a ribbon-like ion beam drawn from each plasma generation container,
Of the ribbon-like ion beam that has passed through the analysis electromagnet, an analysis slit that allows passage of only the ribbon-like ion beam containing desired ions;
A processing chamber into which a ribbon-like ion beam drawn from each plasma generation container is introduced;
A substrate drive mechanism for moving the substrate in a direction intersecting the ribbon-like ion beam so that an ion implantation process is performed on the entire surface of the substrate irradiated with the ribbon-like ion beam in the processing chamber; It is characterized by having.   The analysis electromagnet has a plurality of magnetic pole pairs arranged to oppose each other so as to sandwich a ribbon-like ion beam drawn from each plasma generation vessel from its long side direction, and has a ribbon-like shape drawn from each plasma generation vessel 7. The ion implantation apparatus according to claim 6, wherein the distance between the magnetic poles constituting each magnetic pole pair increases as the distance that the ion beam passes through the analysis electromagnet increases.   The path to the ion source and the processing chamber is provided with a conductive member that potential-separates a path through which a ribbon-like ion beam drawn from each plasma generation container passes. Item 8. The ion implantation apparatus according to Item 6, 6 or 7.   9. The ion implantation apparatus according to claim 5, wherein the ion implantation apparatus includes a beam current measuring device for measuring a beam current density distribution of each ion beam in the processing chamber. According to the measurement result of the beam current measuring device, it is determined whether or not the distribution obtained by combining the beam current density distributions of the respective ion beams is within a desired range. The ion implantation apparatus according to claim 9, further comprising a control device having a function of adjusting an operation parameter of the ion source.

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