KR20120138625A - Ion source and ion implantation apparatus - Google Patents

Abstract

PURPOSE: An ion source and an ion implantation apparatus are provided to form an ion beam of high current by forming one end portion of a cross section of the ion beam to be overlapped. CONSTITUTION: One or more cathodes are included inside each plasma generating container(1). The one or more cathodes arrange a top end portion protruded in the inner side of the plasma generating container on the location which does not contact plasma. A mass flow controller(7) individually controls flow rate of ionized gas introduced within the each plasma generating container. A slit-shaped opening part(11) is formed in the each plasma generating container. A drawing electrode draws out an ion beam of a ribbon shape having a cross section of a rectangular shape.

Description

ION SOURCE AND ION IMPLANTATION APPARATUS}

The present invention relates to an ion source for generating a ribbon (elongated) ion beam and an ion implantation device having the ion source.

The size of substrates (silicon wafers, glass substrates, etc.) that are ion implanted every year is on the rise in size. In order to cope with such an increase in size of the substrate, it has been studied to increase the size of the ion beam irradiated onto the substrate.

As one of methods for increasing the size of an ion beam irradiated onto a substrate, a method of increasing the size of an ion source for generating an ion beam has been considered. As this kind of ion source, what is called a bucket type ion source provided with the some permanent magnet and the some filament which generate the cusp magnetic field as described in patent document 1 has been used.

Japanese Unexamined Patent Publication No. 2000-315473 (Fig. 1)

In the bucket-type ion source described in Patent Literature 1, an ionization gas for ion beam generation introduced into the plasma generation vessel collides with electrons emitted from a plurality of filaments disposed in the plasma generation vessel to generate plasma. And the ion beam is taken out from this plasma by the several sheet electrode which comprises the extraction electrode system arrange | positioned adjacent the opening part of a plasma generation container.

In this kind of ion source, a part (front end) of the filament is disposed in the plasma generated in the plasma generating vessel. The filaments disposed in the plasma for a long time are sputtered by the ions in the plasma and rapidly become smooth. In this case, stable electron supply is impossible, which adversely affects the generation efficiency of plasma generated in the plasma generation vessel. Generally, it is desired to stably supply an ion beam from an ion source for a long time, but when the filament suddenly becomes slender by the above-mentioned sputtering, there is a problem that stable supply of the ion beam becomes impossible.

In addition, when shortening the time required for the ion implantation treatment or when a large amount of ions, called high dose implantation, are injected, the amount of beam current of the ion beam generated from the ion source is increased (large current of the ion beam). This is necessary.

In order to realize such a high current, for example, a method of increasing the amount of electrons emitted from the filament to thicken the generated plasma can be considered. However, an increase in the amount of electrons emitted increases the amount of current flowing through the filament, thereby heating the filament to a higher temperature. Thus, evaporation by heating of the filament proceeds and the filament becomes limp.

In the ion source of Patent Literature 1, when the amount of current flowing through the filament is increased to increase the ion beam, the sputtering action of the filament by the plasma and the evaporation action of the filament due to the high temperature are combined, resulting in the filament being extremely short. It may be consumed. If the filament is broken due to the consumption of the filament, the operation efficiency of the device is deteriorated because the ion source has to be stopped and maintenance is performed.

In view of the above circumstances, the present invention provides an ion source capable of generating a large current and a high current ion beam stably with a smaller disconnection of a filament (cathode) than a conventional ion source, and an ion implantation apparatus having the ion source. It is aimed to do it.

The ion source according to the present invention is provided with a plurality of plasma generating vessels, at least one cathode disposed in each plasma generating vessel, the tip of which protrudes inside the plasma generating vessel and is not in contact with the plasma, and each plasma generating vessel. A flow rate regulator for individually adjusting the flow rate of the ionizing gas introduced into each plasma generation vessel, a slit-shaped opening formed in each plasma generation vessel, and a plane perpendicular to the drawing direction from the slit-shaped opening. Each plasma generating vessel includes an ion source having a drawing electrode for extracting a ribbon-shaped ion beam having a substantially rectangular cross section, and a magnetic field generating means for generating a magnetic field in each plasma generating vessel along a longitudinal direction of the slit-shaped opening. The length of the cross-section of the ribbon-shaped ion beam drawn from As seen in the direction, at least one end in the above cross-sectional length direction and is characterized in that it is configured to overlap each other.

Since the distal end of the cathode is disposed at a position not in contact with the plasma, sputtering of the cathode by the plasma is greatly reduced. Therefore, the cathode is unlikely to be disconnected, and the ion beam can be generated stably for a long time. Further, even if the amount of current flowing to the cathode increases with increasing current, the influence of the sputtering effect by the plasma is small, so that the cathode is not consumed significantly in a short time. Further, when a plurality of plasma generating vessels draw ribbon ion beams having a substantially rectangular cross section in a plane perpendicular to the drawing direction, and viewed them in the short longitudinal direction of the cross section, at least one end in the long longitudinal direction is mutually different. Since it is comprised so that it may be superposed, it can respond to a large board | substrate similarly to the conventional.

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

The magnetic field generating means may be provided in plural, and the magnetic field may be generated independently for each predetermined number of plasma generation vessels.

The magnetic field generating means may be configured to generate a common magnetic field inside each plasma generating vessel. In this case, since there is only one magnetic field generating means, there is an advantage that the maintenance becomes simple.

The ion implantation apparatus according to the present invention is an ion implantation apparatus having the above ion source, and the ion implantation apparatus includes a process chamber into which a ribbon-shaped ion beam drawn out from each plasma generating vessel is introduced, and within the process chamber, the ribbon form. And a substrate driving mechanism for moving the substrate in a direction intersecting with the ribbon-shaped ion beam so that the ion implantation treatment is performed on the entire surface of the substrate to which the ion beam is irradiated.

On the other hand, another ion implantation apparatus according to the present invention is an ion implantation device having the ion source, the ion implantation device is an analysis electromagnet for mass analysis of the ribbon-shaped ion beam drawn out from each plasma generating vessel, and the analysis electromagnet Among the ribbon-shaped ion beams having passed through, an analysis slit for passing only an ion beam containing desired ions, a processing chamber into which ribbon-shaped ion beams drawn out from each plasma generating vessel are introduced, and the ribbon-shaped ion beams in the processing chamber A substrate driving mechanism is provided for moving the substrate in a direction intersecting the ribbon-shaped ion beam so that an ion implantation treatment is performed on the entire surface of the substrate to be irradiated.

In such an ion implantation apparatus, only the ion beam containing the desired ion species can be irradiated to the substrate by mass spectrometry of the ion beam by an analysis electromagnet.

In addition, the analysis electromagnet has a plurality of pairs of magnetic poles opposed to each other so as to sandwich the ribbon-shaped ion beams drawn out from each plasma generating vessel in the long side direction, and the ribbon-shaped ion beams drawn from each plasma generating vessel are analyzed. As the distance passing through the electromagnet becomes longer, it is desired that the distance between the magnetic poles constituting each magnetic pole pair be wider.

Ribbon-shaped ion beams drawn from the plasma generating vessels have different paths through the inside of the analytical electromagnet. If the distance passing through the inside of the analysis electromagnet is long, the amount of deflection of the ribbon-shaped ion beam increases. Then, after passing through the analysis electromagnet, there is a fear that the beam path of the ribbon-shaped ion beam drawn out from each plasma generating vessel crosses. In addition, if the irradiation angle of each ribbon-shaped ion beam to the substrate is excessively different, it adversely affects the characteristics of the device manufactured on the substrate. On the other hand, as described above, the longer the distance between the ribbon-shaped ion beams drawn out from each plasma generation vessel passes through the analysis electromagnet, the larger the distance between the magnetic poles constituting each pair of magnetic poles is. It can be expected to prevent the adverse influence on the characteristics of the device manufactured on the substrate by preventing the crossover of.

Furthermore, it is preferable that a conductive member is disposed in the path between the ion source and the processing chamber to potentially separate the path through which the ribbon-shaped ion beam drawn out from each plasma generation vessel passes.

By using such a conductive member, it is possible to prevent the variation of the spatial potential caused by the space charge effect generated around one ion beam passing through the neighboring beam path from affecting the other ion beam.

In addition, the ion implantation apparatus preferably includes a beam current meter for measuring the beam current density distribution of each ion beam in the processing chamber.

With such a beam current meter, the measurement results can be monitored, and the ion implanter operator can change various parameters of the ion implanter to adjust the beam current density distribution of each ribbon-shaped ion beam irradiated onto the substrate. Will be.

Furthermore, according to the measurement result of the said beam current meter, it is determined whether the distribution which synthesize | combined the beam current density distribution of each ribbon-shaped ion beam is in a desired range, and when it determines with being out of a desired range based on the said decision, It is preferable to have a control device having a function of adjusting operating parameters of the ion source.

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

Compared with the conventional ion source, the disconnection of the filament (cathode) is small, and it is possible to stably generate a large current and a high current ion beam.

1 is a cross-sectional view of a plasma generation vessel used in one ion source according to the present invention.
FIG. 2 is a view of the plasma generation container of FIG. 1 when viewed from the side opposite to the Z direction.
Figure 3 shows an example of the magnetic field generating means used in the ion source according to the present invention.
Figure 4 shows another example of the magnetic field generating means used in the ion source according to the present invention.
5 shows an example of an extraction electrode used in the ion source according to the present invention. (A) is an example of an extraction electrode having a common extraction opening for a plurality of plasma generation vessels, and (B) is an example of an extraction electrode having an individual extraction opening for a plurality of plasma generation vessels.
6 shows an arrangement example of a plasma generating vessel used in an ion source according to the present invention. (A) is an arrangement example of a plurality of plasma generation vessels in which positions in the X direction are staggered along the Y direction, (B) is a modification of the arrangement example shown in (A), and (C) is along the Y direction This is an example of irregularly arranged plasma generation vessel.
7 is a cross-sectional view of a plasma generating vessel used in another ion source according to the present invention.
8 is a plan view of one ion implantation apparatus according to the present invention.
9 shows an example of a beam current meter used in the ion implantation apparatus according to the present invention.
10 is an explanatory diagram according to adjustment of the beam current density distribution measured by the beam current meter. (A) shows the beam current density distribution before adjustment, and (B) shows the beam current density distribution after adjustment.
11 shows an example of an analysis electromagnet used in the ion implantation apparatus according to the present invention. (A) shows the state when the inside of the analysis electromagnet is seen in the Z direction, and (B) shows the state when the analysis electromagnet is seen from the X direction.
12 shows an example of shielding means used in the ion implantation apparatus according to the present invention. (A) shows the state when seeing the shielding means in the Z direction, (B) shows the state when seeing the shielding means in the Y direction.
13 shows an example of a substrate driving mechanism used in the ion implantation apparatus according to the present invention.
14 shows an ion implantation apparatus according to the present invention, in which an ion beam is irradiated onto a substrate.
15 is a plan view of another ion implantation apparatus according to the present invention.

1 is a cross-sectional view of the 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 the ion beam 19 to be described later is drawn out from the plasma generating vessel 1.

The gas supply passage 5 is connected to the wall surface of the plasma generation vessel 1. The gas supply path 5 is equipped with a gas source 6 via a valve 9, and the ionization gas serving as a raw material of the ion beam 19 is supplied from the gas source 6. In addition, a gas flow regulator 7 (mass flow controller) is provided in the gas supply passage 5, whereby the supply amount of the ionized gas from the gas source 6 into the plasma generation vessel 1 is adjusted.

One side of the plasma generating vessel 1 is mounted with a U-shaped filament 2 via an insulator 10. A filament power supply V _F is connected between the terminals of the filament 2, and it is comprised so that the amount of electric current which flows into the filament 2 can be adjusted. The filament power source (V _F) is connected to the plasma generation chamber 1 via the arc power source (V _A).

By passing a current through the filament 2 and heating the filament 2, electrons are emitted there. The magnetic field B is generated in the plasma generating container 1 in the direction of the arrow shown in the plasma generating container 1 by the magnetic field generating means 12 to be described later, and the filament ( The electrons emitted in 2) move. The electrons collide with the ionization gas (PH ₃ , BF _3, etc.) supplied inside the plasma generation vessel 1 to cause ionization of the ionization gas, and the plasma 3 is generated in the plasma generation vessel 1.

The filament 2 of this invention is arrange | positioned in the position which the front-end | tip part located in a X direction does not contact the plasma 3 ,. For this reason, the sputtering of the filament 2 by the plasma 3 can be reduced. Only one filament 2 is drawn here, but a plurality of filaments 2 may be arranged in the same manner as in the prior art.

In the plasma generating vessel 1, a reflective electrode 4 is provided at a position facing the filament 2. The reflective electrode 4 is attached to the plasma generation vessel 1 via the insulator 10, and the power supply V _B is connected to the negative potential with the plasma generation vessel 1 as the reference potential. . In this way, by making the potential of the reflective electrode 4 into the negative potential, when the electrons emitted from the filament 2 are moved 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 ionization gas and the electrons is improved, and the generation efficiency of the plasma 3 can be improved. On the other hand, the reflective electrode 4 is for improving the generation efficiency of the plasma 3, and is not necessarily provided.

Also in this case, but by using a power source (V _B) configuration and the potential of the reflecting electrode 4, so that the negative potential, without using such a power supply, it is left at a floating potential. In this case, the electrons emitted from the filament 2 impinge on the reflective electrode 4, so that the reflective electrode 4 is negatively charged, and finally the electrons can be reflected to the filament 2 side. Although not shown, a reflective electrode may be provided on the back side of the filament 2.

2 shows a state of the plasma generating container 1 when FIG. 1 is viewed from the opposite side in the Z direction. As shown in FIG. 2, the slit-shaped opening 11 is formed in the side surface located in the Z direction side of the plasma generation container 1, and the extraction electrode 16 mentioned later through this place is used, The ion beam 19 is taken out.

In the present invention, the ion source 8 is constituted by the plurality of plasma generating vessels 1. In FIG. 3, as an example, an example having four plasma generating vessels U11, U12, U21, and U22 arranged in a matrix is disclosed. The plasma generating vessels U11, U12, U21 and U22 have the same configuration as the plasma generation vessel 1 described with reference to FIG. 1.

As described in FIG. 1, the ion source 8 of the present invention is provided with magnetic field generating means 12 for generating the magnetic field B in the plasma generating vessel 1. In the example of FIG. 3, the example of the magnetic field generating means 12 which generate | occur | produces the magnetic field B common to all four plasma generating vessels U11, U12, U21, and U22 is shown.

The magnetic field generating means 12 illustrated in FIG. 3 is a yoke 13 having a substantially lo-shaped yoke 13 in which each plasma generating vessel U11, U12, U21, U22 is disposed and along the X direction in the yoke 13. A pair of magnetic poles 14 protruding to the inner region (the region on which the plasma generating vessel is placed) of 13 is disposed to face each other. Coils 15 are wound around each magnetic pole 14, and each coil 15 is connected to a power source (not shown).

For example, if the magnetic pole 14 located on the upper side of the ground flows the current to each coil 15 such that the magnetic pole 14 located on the lower side of the ground becomes the N pole, the respective plasma as shown in FIG. The magnetic field B common to the inner regions of the production containers U11, U12, U21, U22 is generated.

In the example of FIG. 3, the magnetic field B common to the inner region of each of the plasma generating vessels U11, U12, U21 and U22 is generated using one magnetic field generating means 12. Instead, as shown in FIG. A plurality of magnetic field generating means 12 may be provided. In the example of FIG. 4, the magnetic field generating means 12 is provided separately in the tank which consists of plasma generation vessels U11 and U12, and the tank which consists of plasma generation vessels U21 and U22. Since the configuration of each magnetic field generating means 12 is the same as that described in the above-described example, detailed description thereof will be omitted, but the magnetic field generating means 12 independently generates magnetic fields for each plasma generating vessel tank. You can do it. On the other hand, in the example of FIG. 4, the magnetic field B1 is generated for the tank made of the plasma generation vessels U11 and U12, whereas the magnetic field B2 is generated in the tank made of the plasma generation vessels U21 and U22. The magnetic field generated for the pair may be the same.

In the example of Fig. 4, the two plasma generating vessels are constituted so as to correspond to one magnetic field generating means 12, but one magnetic field generating means 12 may be corresponded to each plasma generating vessel. Furthermore, one tank may be comprised by two plasma generation vessels, and the other tank may be comprised by three plasma generation vessels. In this case, as in the previous example, one magnetic field generating means 12 is provided for each pair. In addition, although the electromagnet was used as the magnetic field generating means 12 here, a permanent magnet may be used instead. In this case, two permanent magnets may be prepared and attached to each magnetic pole 14 so that different polarities are arranged opposite 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 generating vessel 1. The structure of this lead-out electrode 16 is demonstrated based on FIG. 5 (A) and 5 (B), four plasma generating vessels U11, U12, U21, and U22 as an example in FIGS. 3 and 4 and the extraction electrodes 16 disposed in front (Z direction side) thereof. ) Is shown. Meanwhile, in this figure, each of the plasma generating vessels U11, U12, U21, and U22 and the slit-shaped openings 11 formed in the plasma generating vessel are shown by broken lines.

In this example, an ion beam having a positive charge is assumed as the ion beam to be drawn out. Therefore, a power source (not shown) is connected to the extraction electrode 16 in which the potential of the extraction electrode 16 becomes a negative potential on the basis of the plasma generating vessels U11, U12, U21, and U22. The structure of the lead-out electrode 16 is demonstrated concretely. In the example of FIG. 5A, two lead openings 17 are formed in one large lead-out electrode 16. Each lead-out opening 17 is provided separately for the tank which consists of the plasma generation container U11 and the plasma generation container U12, and the tank which consists of the plasma generation container U21 and the plasma generation container U22.

In Fig. 5A, one drawing opening 17 is arranged for two plasma generating vessels, but instead, as shown in Fig. 5B, each of the plasma generating vessels is individually drawn out. The opening 17 may be provided. In addition, although not shown here, the ion beam 19 drawn out through the drawing opening 17 of the drawing electrode 16 has a ribbon-shaped ion beam having a substantially rectangular cross section in a plane perpendicular to the drawing direction (Z direction). Becomes

3 to 5 show an example in which four plasma generation vessels are arranged, but the arrangement of the plasma generation vessel of the present invention is not limited thereto. 6A to 6C show arrangement examples of the plasma generation vessel constituting the ion source 8 of the present invention.

In the present invention, when the ribbon-shaped ion beams drawn out from the plasma generating vessels are cut in a plane perpendicular to the drawing direction, and the ribbon-shaped ion beams are viewed from the short length direction of the cut surface in the substantially rectangular cut surface at that time, At least one end part in the long longitudinal direction of a cut surface is overlapped with each other, It is characterized by the above-mentioned. In this way, even when the substrate size becomes large, ion implantation can be performed without any problems as in the prior art. The substantially rectangular cross section of the ribbon ion beam 19 drawn out by the extraction electrode 16 is substantially the same as the shape of the slit-shaped opening 11 formed in each plasma generation container. Therefore, as shown in Figs. 6A to 6C, each plasma generating vessel can be arranged.

Specifically, in Fig. 6 (A), in the Y-direction, the tanks of the plasma generation vessels arranged in odd-numbered (joins composed of U11 and U12, groups composed of U31 and U32) and plasma generation arranged evenly The position in the X direction of the tank (the tank which consists of U21 and U22, the tank which consists of U41 and U42) differs. The position in the X direction of the plasma generation vessel tanks arranged in the odd-numbered number and the plasma generation vessel tanks arranged in the even-numbered number is short in the Y-direction (a substantially rectangular cut plane when the ribbon-shaped ion beam is cut in a plane perpendicular to the extraction direction). Corresponds to the long length direction of the substantially rectangular cut surface when the ribbon-shaped ion beam is cut in a plane perpendicular to the extraction direction in the X-direction of the slit-shaped opening 11 formed in the adjacent plasma generating vessel in the longitudinal direction. At least one end in) is arranged so as to overlap each other. By arranging in this way, when the ribbon-shaped ion beams 19 drawn from each plasma generating vessel are viewed in the short length direction of the substantially rectangular cross section, at least one end portion in the long length direction of the substantially rectangular cross section is superimposed on each other. Can be.

In Fig. 6A, an example in which the positions in the X direction between the odd-numbered plasma generation vessel and the even-numbered plasma generation vessel are alternated with each other is shown, but this may be modified as shown in Fig. 6B. In Fig. 6 (B), the plasma generation vessels arranged in the 1st and 4th (joints consisting of U11 and U12, the group consisting of U41 and U42) and the plasma generating vessels arranged in the second and third in the Y direction. The positions in the X direction of the (a group consisting of U21 and U22 and a group consisting of U31 and U32) are arranged differently. Even in this case, the same effects as those of the example shown in FIG. 6A can be obtained.

In addition, as shown in Fig. 6C, the configuration of each plasma generating vessel tank arranged in the Y direction may be changed. Here, the number of plasma generating vessels arranged in the first and second in the Y direction is one, and the number of plasma generating vessels arranged in the third is two. Even in such a configuration, the substantially rectangular cut surface of the slit-shaped opening 11 formed in each of the plasma generating vessels U11, U21, U31, and U32 (when the ribbon-shaped ion beam is cut in a plane perpendicular to the extraction direction). At least one end in the long longitudinal direction is arranged so as to be superimposed when viewed in the Y direction (corresponding to the short longitudinal direction of the substantially rectangular cut plane when the ribbon-shaped ion beam is cut in a plane perpendicular to the extraction direction). If it is, the same effect as FIG. 6 (A) and FIG. 6 (B) shown previously can be exhibited. Of course, the number of plasma generating vessels is not limited to that presented here. The number of plasma generating vessels should just be 2 or more.

The configuration of the plasma generation vessel 1 shown in FIG. 7 is different from the cathode portion as described in FIG. 1. In the example of FIG. 7, the cathode which emits electrons is comprised by the heat radiation type cathode 18. As shown in FIG. This configuration is known as a heat radiation type ion source. An electric current is sent to the filament 2 with the filament power supply V _F , and the filament 2 is heated to emit electrons. With the filament 2 as the reference potential, the cathode power supply V _C is connected so that the potential of the heat dissipating cathode 18 becomes a more positive potential. By this cathode power supply V _C , electrons emitted from the filament 2 are attracted to the heat dissipating cathode 18 and dropped thereon. When electrons fall on the heat dissipating cathode 18, the heat dissipating cathode 18 is heated, and when heated to a certain temperature, electrons are emitted from the heat dissipating cathode 18. Since the plasma 3 is generated in the same manner as in the example of FIG. 1, the description thereof is omitted here. However, such a heat radiation cathode 18 may be used as the cathode for emitting electrons. On the other hand, the interior of the plasma generation vessel in the present invention means a region including an opening in which the heat radiation cathode 18 formed in the plasma generation vessel is disposed.

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 illustration of the magnetic field generating means 12, the extraction electrode 16, and the like described above are omitted. In addition, for the sake of simplicity of the following description, as the configuration of the plurality of plasma generation vessels, here, two plasma generation vessels U11 and U21 among the four plasma generation vessels U11, U12, U21 and U22 shown in FIG. The configuration provided is taken as an example.

The ion beams 19 drawn out from each of the plasma generating vessels U11 and U21 include those other than the desired ion species. Therefore, in order to irradiate only the desired ion species to the board | substrate 23, the mass spectrometry is performed using the analysis electromagnet 20 and the analysis slit 21, as is conventionally known. The mass analyzed ion beam 19 is irradiated to the beam current meter 25 disposed in the process chamber 22. In the beam current meter 25, the beam current density distribution is measured along the X direction as described later, and the measurement result is transmitted to the control device 26 as a signal S9. When the control device 26 determines 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 receiving the control signal S7 uses two ion beams 19 to intersect the ion beam 19 so that the ion beam 19 is irradiated on the front surface of the substrate 23 ( In this case, the substrate 23 is driven in the 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 the control signals S1 to S4 to the ion source 8, and the filament power source (e.g., provided in the ion source 8) The operating parameter values of the ion source such as V _F ), the arc power source V _A , the mass flow controller 7, and the cathode power source V _C are adjusted. In addition to the adjustment of this operating parameter, a shielding means 27 for partially shielding each ion beam 19 is provided on the downstream side (the processing chamber 22 side) of the analysis slit 21, and the beam current is used using this. The density distribution may be adjusted. On the other hand, this shielding means 27 is controlled by the control signal S6 from the control apparatus 26, and adjustment of the movement amount in the arrow direction shown is performed. In the beam current density distribution adjustment, the beam current density distribution is monitored by the beam current meter 25.

The path of the ion beam 19 drawn out from each of the plasma generating vessels U11 and U21 is electrically displaced by the conductive member 31 having a mesh-shaped hole between the ion source 8 and the processing chamber 22. It is separated. The conductive member 31 is made of, for example, carbon which is a nonmagnetic material, and is electrically grounded. When the beam paths of the two ion beams 19 are electrically separated by the conductive member 31, the variation in the spatial potential generated around the one ion beam 19 due to the space charge effect is different from the other ion beam 19. ) Can be prevented. In addition, since each ion beam has a positive charge, it repels each other when too close. However, if such a conductive member 31 is provided, it is potentially separated, so that the two ion beams 19 can be arranged in close proximity, and the ion implantation device IM can be miniaturized or the substrate driving mechanism 24 can be used. The driving range of the board | substrate 23 at the time of performing an ion implantation process on the whole surface of the board | substrate 23 can be narrowed.

Each part which comprises the ion implantation apparatus IM is demonstrated below. An example of a beam current meter 25 is shown in FIG. 9. In the beam current meter 25, a plurality of Faraday cups 40 long in the Y direction are disposed along the X direction. The Faraday cup 40 is large enough to cover the two ion beams 19 drawn from the plasma generating vessels U11 and U21 in the Y direction, and the other from one end of the two ion beams 19 in the X direction. It is arrange | positioned in multiple numbers so that the edge may be covered.

The measurement result of this beam current meter 25 is shown on the right side of the page of the beam current meter 25 shown in FIG. In this measurement result, the vertical axis represents the position on the beam current meter 25, and the horizontal axis represents the magnitude of the beam current density. Focusing on the beam current density distribution of each ion beam 19, the beam current density in the vicinity of the center portion of the ion beam 19 is large and becomes a smooth distribution as it goes to the end. In this example, the end part in the X direction of each ion beam 19 drawn out from the plasma generation container U11 and the plasma generation container U21 is superimposed when viewed from the Y direction. The overlapped portion is located in the area indicated as A in the measurement result. In this area, the beam current density distribution by each ion beam 19 decreases gently as indicated by the broken line, but in this case, each ion beam 19 ), The current density is overlapped, and the beam current density distribution as described by the solid line is measured.

A method for obtaining a desired beam current density distribution will be briefly described with reference to FIGS. 10A and 10B. 10A shows the beam current density distribution measured by the beam current meter 25. It is assumed here that the value of the beam current density is H ± α and the ion implantation into the substrate 23 is performed using the ion beam 19 having a width in the X direction.

In this case, the beam current density values exceed the range of H + alpha in the regions of C and D shown. Therefore, the beam current density in this area must be reduced. In this case, for example, the filament power source V _F is controlled by the controller 26, so that 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 beam amount of the ion beam 19 withdrawn from the plasma generation vessel 1 is reduced. As a result, as shown in Fig. 10B, the beam current density distribution is reduced as a whole to satisfy the predetermined range.

Although a control example for adjusting the filament power supply V _F has been described, other than this, the arc power supply V _{C included} in the ion source 8 described above, the gas flow rate introduced into the plasma generating vessel, or the like may be controlled. In addition, as a control object, the order is decided previously, the order is memorize | stored in the control apparatus 26, and the method of controlling a control object according to a predetermined order can be considered. In this case, the order of control 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 parameter suitable for coarse adjustment (parameter with which the beam current density distribution fluctuates greatly with a slight adjustment), and if the difference is small, the parameter suitable for fine adjustment (near the beam even with a large amount of adjustment). A parameter in which the current density distribution does not change) may be adjusted to determine the order of operation parameters to be adjusted.

On the other hand, the operator (operator) of the ion implantation device IM may be adjusted manually without providing the control device 26. In this case, a method of preparing a monitor for displaying the measurement result by the beam current measuring device 25 and looking at this monitor can be considered to allow the operator to adjust the measured beam current density distribution to fall within a desired range. have.

In addition, the structure of the beam current measuring device 25 is not a structure in which a plurality of ion beams 19 are collectively measured, but beams are individually for each ion beam 19 so that each ion beam 19 can be individually measured. You may provide the current measuring device 25. In that case, the measurement result may be summed up later.

11 (A) and 11 (B) are examples of the analysis electromagnet 20 described in FIG. 8. FIG. 11A shows a cross section of the analysis electromagnet 20. The analysis electromagnet 20 is provided with the yoke 28, and the yoke 28 is provided with the 1st magnetic pole pair 29 and the 2nd magnetic pole pair 30 from which the distance (gap) between magnetic poles in an X direction differs. . In the Y direction, the coil 15 is wound so as to cover both the magnetic poles of the first magnetic pole pair 29 and the second magnetic pole pair 30 which are arranged in the X direction, and in this example, the angles arranged below the paper surface. In the magnetic pole pairs, a magnetic field is generated toward each magnetic pole pair disposed above the ground. In addition, the first magnetic pole pair 29 and the second magnetic pole pair 30 are configured to independently change the distance between magnetic poles by the magnetic pole driving mechanism 39 made of a motor or the like.

An ion beam 19 drawn from the plasma generating vessel U11 shown in FIG. 8 passes between the first pair of magnetic poles 29, and similarly, the plasma generating vessel U21 shown in FIG. 8 is passed between the second pair of magnetic poles 30. The ion beam 19 drawn out from passes through. Moreover, in the Y direction, the electroconductive member 31 is provided so that the beam path of each ion beam 19 may be separated potentially.

The turning radius of the ion beam 19 drawn out from each of the plasma generating vessels U11 and U21 has the same turning radius in the analysis electromagnet 20 when the desired ion species and the energy of the ion beam are the same. Although it depends also on the distance to the analysis electromagnet 20, the board | substrate 23, etc., when the turning radius is the same, there exists a possibility that the path | route of each ion beam 19 may cross | intersect. In addition, when the difference in the angle of incidence to the substrate 23 by each ion beam 19 becomes large, the characteristic of the device manufactured on the board | substrate will change according to a place. Therefore, it is desired to adjust the turning radiuses of the ion beams 19 drawn out from each of the plasma generating vessels U11 and U21 so that the trajectories of both ion beams 19 are as parallel as possible.

In the case of Fig. 8, each ion beam 19 is pivoted clockwise with the analysis electromagnet 20, so that the ion beam 19 is pivoted outward (located on the Y-direction side in Fig. 11 (A)) (plasma generating vessel). It is necessary to make the turning radius of the ion beam 19 drawn out at U11 larger than the turning radius of the other ion beam 19 (the ion beam 19 drawn out from the plasma generating vessel U21) turning inside. have. When the ion species and the energy of the ion beam 19 are the same, the turning radius is different depending on the intensity of the magnetic field for turning the ion beam 19. Since the intensity of the magnetic field becomes weaker as the distance between the magnetic poles becomes wider, in this example, the distance between the magnetic poles of the first magnetic pole pair 29 is made larger than the distance between the magnetic poles of the second magnetic pole pair 30. Although the magnitude relationship between the distances between the magnetic poles is as described above, how to set the distance between the magnetic poles, the distance to the analysis electromagnet 20 and the substrate 23, the characteristics of the device manufactured on the substrate 23, etc. It is appropriately set according to various conditions.

By varying the distance between the magnetic poles as described above, the first magnetic field B3 generated in the first magnetic pole pair 29 can be made weaker than the second magnetic field B4 generated in the second magnetic pole pair 30. Depending on how the distance is set, the beam path of each ion beam 19 can be made nearly parallel. Here, in the analysis electromagnet 20, the ion beam 19 that pivots outward in order to make the turning radius of the ion beam 19 that pivots outwards larger than that of the other ion beam 19 pivoting inwards. Although the expression that the distance between the magnetic poles passing through is wider than the distance between the magnetic poles passing through the other ion beam 19 is used, this can be expressed as follows. The longer the distance the ion beam passes through the inside of the analysis electromagnet 20 is, the wider the distance between the magnetic poles formed in the analysis electromagnet 20 is. That is, in the analysis electromagnet 20, the distance through the inside of the analysis electromagnet 20 becomes longer as the ion beam 19 passes through the outside. On the contrary, in the analysis electromagnet 20, the distance through the inside of the analysis electromagnet 20 becomes shorter as the ion beam 19 passes through the inside. Therefore, instead of the expression inside and outside, the expression "distance through which the ion beam 19 passes through the analysis electromagnet 20" can be used.

The width | variety in the Y direction of the pole 29 and the pole 30 is made large enough compared with the dimension in the same direction of the ion beam 19 which passes through it. It is also desirable that the ion beam 19 passing between the magnetic poles be configured to pass through the central portion of each magnetic pole in the Y direction. This is because magnetic field interference occurs at magnetic pole ends arranged between adjacent magnetic poles in the Y-direction, which may cause a disturbance in mass spectrometry of the ion beam 19. For this reason, it is preferable to set the passage position of the ion beam passing through the magnetic pole dimension and the magnetic pole as described above.

FIG. 11 (B) shows a state when the analysis electromagnet 20 is viewed in the X direction. In this figure, the dashed-dotted line described in the inner region of the analysis electromagnet 20 represents the external 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. As shown in FIG. The dashed line indicates the conductive member 31. As can be seen from this figure, the width of the first pair of magnetic poles 29 and the width of the second pair of magnetic poles 30 are the same along the beam path of the ion beam 19, respectively. In addition, the X axis | shaft, Y axis | shaft, and Z axis | shaft described in FIG. 11 (B) have shown the direction in the exit (right side of the surface) of the analysis electromagnet 20, and this direction except the X-axis direction in the analysis electromagnet 20 inside. Are changed accordingly.

12 (A) and 12 (B), an example of the shielding means 27 described in FIG. 8 is described. As shown here, for example, the shielding means 27 is provided separately with respect to the ion beam 19 drawn out from each of the plasma generating vessels U11 and U21. The shielding means 27 is provided with a pair of shielding members 34 opposed to each other so as to sandwich each ion beam 19 in its short side direction (Y direction), and a pair of shielding members 34 Is arranged along the long side direction (X direction) of the ion beam 19.

A support shaft 33 is connected to each shielding member 34, and the support shaft 33 is independently moved in the direction of the arrow shown by the shielding member drive mechanism 32, thereby forming a part of the ion beam 19. Is shielded to adjust the beam current density distribution. As the shielding member drive mechanism 32, for example, it is conceivable to have a plurality of motors as a power source, and to be constituted by a mechanism for driving each support shaft 33 individually.

FIG. 12 (B) shows a state when the shielding means 27 is viewed from the Y direction. As shown in this figure, the plurality of shielding members 34 are arranged in a zigzag shape so that their positions in the Z direction are staggered along the X direction. With this arrangement, the current density distribution of the ion beam 19 can be adjusted seamlessly over the entire X direction.

13 shows an example of the substrate driving mechanism 24 described in FIG. The substrate driving mechanism 24 includes a substrate holder 38 for supporting the substrate 23 and extends along the Z direction at the lower end surface (section located on the X-direction side) and the lower end surface of the substrate holder 38. The lower end is supported by four rotary bodies 37. The two rotary bodies 37 supporting the lower end face of the substrate holder 38 are rotatable in the direction of the arrow shown by the support shaft 36 mounted on the support 41 disposed on the processing chamber 22. Supported. The rotating body 37 supporting the Z direction side of the lower end of the substrate holder 38 is rotatably supported in the arrow direction shown by the support shaft 36 provided on the processing chamber 22. On the other hand, the rotating body 37 supporting the opposite side in the Z direction of the lower end is fixed to the rotation shaft 43 of the driving source 42 (motor) provided on the outside of the processing chamber 22 via the vacuum seal 35, and the driving source ( The rotary shaft 43 is rotated by 42 to be integral with the rotary shaft 43 and rotated in the direction of the arrow shown. For this reason, the board | substrate holder 38 can be moved to a Y direction. On the other hand, although not shown in figure, the support mechanism of the board | substrate holder 38 which has the above four rotating bodies 37 is provided in multiple numbers along the Y direction.

In FIG. 14, the ion beams 19 drawn from the plasma generating vessels U11 and U21 are irradiated onto the substrate 23. Since the substrate 23 moves in the direction crossing the two ion beams 19 along the Y direction (in this example, the Y direction), ion implantation into the entire surface of the substrate 23 is thereby achieved.

<Other variations>

In the example of FIG. 8, the position in the Z direction of the plasma generation container U11 and the plasma generation container U21 was made the same. In that case, the distance of the beam path until the ion beam 19 drawn out from each plasma generation vessel is irradiated to the substrate is different. If the distance between the beam paths is different, the effect of the space charge effect received by each ion beam 19 is different, and therefore, the shape of the ion beam 19 irradiated to the substrate 23 will be different. In the example of FIG. 8, the number of plasma generation vessels is two, but as the number of plasma generation vessels 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 irradiated to the board | substrate 23 is substantially the same, the beam current density distribution of each ion beam 19 can be easily controlled. This is because it can be expected to adjust the current density distribution of another ion beam by using the result obtained by adjusting the current density distribution of one ion beam.

Therefore, as shown in FIG. 15, the position in the advancing direction of the ion beam 19 of each plasma generation container U11, U21 is changed, and it is carried out from each plasma generation container U11, U21 to the board | substrate 23. FIG. The distance L1 and L2 until the ion beam 19 is irradiated are made to be the same distance. With such a configuration, the shapes of the ion beams 19 drawn out from the plasma generation vessels U11 and U21 at the irradiation position to the substrate 23 can be made substantially the same.

It goes without saying that various improvements and modifications may be made without departing from the gist of the present invention.

1, U11, U12, U21, U22, U31, U32, U41, U42 Plasma generating vessel
2 filaments 3 plasma
7 Gas flow regulator 8 Ion source
11 Slit-shaped opening 12 Magnetic field generating means
16 lead-out electrode 17 lead-out opening
19 Ion Beam 20 Analytical Electromagnets
21 Analysis Slits 23 Substrate
24 Substrate Driving Mechanism 31 Conductive Member
IM ion implanter

Claims (12)

A plurality of plasma generating vessels,
At least one cathode provided in each plasma generation vessel, the tip portion protruding in the plasma generation vessel and disposed at a position not in contact with the plasma;
A gas flow regulator connected to each plasma generation vessel and individually adjusting a flow rate of the ionization gas introduced into each plasma generation vessel;
A slit-shaped opening formed in each plasma generating container,
An extraction electrode for taking out a ribbon-shaped ion beam having a rectangular cross section in a plane perpendicular to the extraction direction from the slit-shaped opening;
An ion source provided with magnetic field generating means for generating a magnetic field in each plasma generating vessel along a longitudinal direction of the slit-shaped opening,
An ion source characterized in that at least one end portion in the long longitudinal direction of the cross section is overlapped with each other when the ribbon-shaped ion beam drawn out from each plasma generation vessel is viewed in the short longitudinal direction of the cross section. The method of claim 1,
The ion source in the longitudinal direction of the slit-shaped opening is provided with a reflective electrode disposed opposite to the cathode in the plasma generation vessel. The method of claim 1,
The magnetic field generating means is provided with a plurality, the ion source, characterized in that for generating a magnetic field independently for each predetermined number of plasma generation vessel. The method of claim 1,
And said magnetic field generating means generates a common magnetic field inside each plasma generating vessel. An ion implantation apparatus comprising the ion source according to any one of claims 1 to 4,
The ion implantation apparatus includes a processing chamber into which a ribbon-shaped ion beam drawn out from each plasma generating vessel is introduced;
And a substrate driving mechanism for moving the substrate in a direction intersecting with the ribbon-shaped ion beam so that the ion implantation treatment is performed on the entire surface of the substrate to which the ribbon-shaped ion beam is irradiated in the processing chamber. Ion injection device characterized in that. An ion implantation apparatus comprising the ion source according to any one of claims 1 to 4,
The ion implantation apparatus includes an analysis electromagnet for mass analysis of ribbon-shaped ion beams drawn out from each plasma generating vessel;
An analysis slit for passing only a ribbon ion beam containing desired ions among the ribbon ion beams passing through the analysis electromagnet;
A processing chamber into which ribbon ion beams drawn out from each plasma generating vessel are introduced;
And a substrate driving mechanism for moving the substrate in a direction intersecting the ribbon-shaped ion beam so that an ion implantation treatment is performed on the entire surface of the substrate to which the ribbon-shaped ion beam is irradiated in the processing chamber. Ion injection device. The method according to claim 6,
The analysis electromagnet has a plurality of pairs of magnetic poles opposed to each other so as to sandwich the ribbon-shaped ion beams drawn out from each plasma generation vessel in the long-direction, and the ribbon-shaped ion beams drawn out from each plasma generation vessel The ion implantation apparatus characterized in that the distance between the magnetic poles constituting each magnetic pole pair is wider as the distance passing therethrough increases. The method of claim 5,
And an electroconductive member for disposing potential paths through which ribbon-shaped ion beams drawn out from the plasma generating vessels pass through the paths between the ion source and the processing chamber. The method according to claim 6,
And an electroconductive member for disposing potential paths through which ribbon-shaped ion beams drawn out from the plasma generating vessels pass through the paths between the ion source and the processing chamber. The method of claim 5,
And the ion implantation device comprises a beam current meter for measuring the beam current density distribution of each ion beam in the processing chamber. The method according to claim 6,
And the ion implantation device comprises a beam current meter for measuring the beam current density distribution of each ion beam in the processing chamber. 10. The method of claim 9,
According to the measurement result by the beam current meter, it is judged whether or not the distribution obtained by combining the beam current density distribution of each ion beam is within a desired range, and when it is determined out of the desired range based on the determination, An ion implantation device comprising a control device having a function of adjusting operation parameters.

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