TW202437296A - Ion source - Google Patents

Abstract

An ion source comprising: a plasma-generating means provided with a plasma-generating vessel that has an internal space into which an ion source gas is introduced, the plasma-generating vessel having an ion extraction port formed in one side wall thereof, an antenna that ionizes the ion source gas to generate plasma in the internal space, the antenna being provided outside the plasma-generating vessel and being connected to a high-frequency power source to generate a high-frequency magnetic field, and a magnetic field transmission window that is formed in a side wall of the plasma-generating vessel at a position facing the antenna and that allows the high-frequency magnetic field generated from the antenna to pass through the internal space; a discharge electrode provided in the internal space near the ion extraction port; and an extraction electrode system that is provided outside the plasma-generating vessel and that extracts an ion beam from the internal space through the ion extraction port.

Description

Ion source

The present invention relates to an ion source used in, for example, an ion implantation device.

As such an ion source, as shown in Patent Document 1, there is an ion source having the following components: a plasma generation container into which ion source gas is introduced and which is in a rectangular parallelepiped shape; a plurality of magnets arranged outside the side surface of the plasma generation container and forming a cusp magnetic field inside the plasma generation container; and a filament inserted from the side wall of the plasma generation container to the inside and emitting electrons. In the ion source, the plasma generation container also serves as an anode, and the electrons emitted from the filament are discharged in the plasma generation container, so that the ion source gas is ionized to generate plasma. Furthermore, the ion beam is extracted from the plasma using an extraction electrode system disposed near an ion extraction port formed on a side wall of a plasma generation container. [Prior art literature] [Patent literature]

[Patent Document 1] Japanese Patent Publication No. 2011-228044

[Problem to be solved by the invention] In the ion source in which the filament is inserted from the side wall of the plasma generating container as described above, a negative voltage is applied to the plasma generating container in order to generate plasma, so the filament is consumed by sputtering based on positive ions. In particular, when plasma is generated using an ion source gas such as a halogenide such as _BF3 , the filament is further consumed by sputtering accompanied by a chemical reaction. As the consumption of the filament increases, it becomes necessary to perform maintenance such as replacement, and therefore, in the conventional ion source, the life of the filament is the main factor determining the maintenance cycle of the ion source.

In addition, in order to generate roughly uniform plasma in the plasma generating container, multiple filaments need to be installed, and each filament needs to be provided with a power supply, so the number of parts increases and the device becomes larger. In addition, the processing time required for its installation also increases due to the increase in the number of parts, and the number of control points also increases proportionally due to the increase in power supply, and the cost becomes higher. Furthermore, due to the installation of multiple filaments, the number of high-current cables for filament wiring also increases, which also complicates the wiring path and causes poor workability during maintenance. In addition, it is also intended to further increase the plasma density near the ion extraction port.

The present invention is designed to solve the above problems in one fell swoop. The main subject is to provide an ion source with a long maintenance cycle and good maintenance performance, thereby achieving miniaturization of the entire device, suppressing manufacturing costs, and increasing the plasma density near the ion extraction port. [Means for solving the problem]

That is, the ion source of the present invention is characterized in that it comprises: a plasma generating container, which is a container having an internal space for introducing ion source gas, and an ion introduction port is formed on one side wall thereof; a plasma generating unit, which ionizes the ion source gas to generate plasma in the internal space, and comprises an antenna and a magnetic field transmission window, wherein the antenna is arranged outside the plasma generating container and connected to a high frequency power source to generate A high-frequency magnetic field, wherein the magnetic field transmission window is formed on the side wall of the plasma generating container facing the antenna, so that the high-frequency magnetic field generated by the antenna is transmitted to the internal space; a discharge electrode is arranged near the ion extraction port in the internal space; and an extraction electrode system is arranged outside the plasma generating container to extract the ion beam from the internal space through the ion extraction port. [Effect of the invention]

The present invention thus constructed can provide an ion source having a long maintenance cycle and good maintenance performance, thereby achieving miniaturization of the entire device, suppressing manufacturing costs, and increasing the plasma density near the ion extraction port.

The ion source of the present invention is used in, for example, an ion implantation device or an ion doping device plasma beam irradiation device used in a semiconductor manufacturing step or a flat panel display manufacturing step. Hereinafter, an ion implantation device 400 including an ion source 100 according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG1 , the ion implantation device 400 of the present embodiment is used to perform ion implantation by irradiating an ion beam IB onto a target substrate W. Specifically, the ion implantation device 400 includes: an ion source 100 that extracts an ion beam IB along a predetermined extraction direction; a mass analysis unit 200 that is disposed on the downstream side of the ion source 100 and performs mass analysis of the ion beam IB extracted from the ion source 100; and a processing chamber 300 in which the substrate W is disposed. In the ion implantation device 400 of the present embodiment, a ribbon-shaped ion beam IB is extracted from the ion source 100, and the width in the front and back directions of the paper surface of FIG1 is sufficiently greater than the thickness in the direction orthogonal thereto.

The mass analysis unit 200 has a mass analysis magnet 210 and an analysis slit 220. The mass analysis magnet 210 bends the ion beam IB along its thickness direction and then selects and guides out the desired ions. The analysis slit 220 is disposed on the downstream side of the mass analysis magnet 210, and by cooperating with the mass analysis magnet 210, the desired ions are selected and passed through. At the entrance of the mass analysis magnet 210, a slit plate 211 forming an incident slit is disposed. The slit plate 211 limits the incident angle and beam width of the ion beam IB when incident on the mass analysis unit 210, thereby improving the analysis performance of the ion beam passing through the analysis slit 220.

In the processing chamber 300, the substrate W is held by the substrate driving device 310 in such a manner that the processing surface thereof faces the ion beam IB. The substrate driving device 310 is configured to mechanically reciprocate in a direction along the thickness of the ion beam IB incident on the substrate W while holding the substrate W. The ion implantation device 400 can implant the ion beam IB into the entire surface of the substrate W by reciprocatingly driving the substrate W by the substrate driving device 310 and irradiating the ion beam IB in a strip shape, thereby implanting ions.

The following is a detailed description of the structure of the ion source 100. In each figure, only the main part of the ion source 100 according to the embodiment of the present invention is shown, and various components are omitted.

Specifically, as shown in FIG. 2 and FIG. 3 , the ion source 100 includes: a plasma generating container 1 for introducing ion source gas to generate plasma; a plurality of magnets 2, which are arranged outside the plasma generating container 1 and form a magnetic field (specifically also called a cusp magnetic field, more strictly speaking also called a multi-cusp magnetic field, also called a multipole magnetic field) in the plasma generating container 1; a plasma generating unit 3, which forms plasma in the plasma generating container 1; an extraction electrode system 4, which extracts the ion beam IB from the plasma generating container 1; and a gas source 5, which supplies the ion source gas to the plasma generating container 1 at a certain flow rate.

The plasma generating container 1 is a long container such as a rectangular parallelepiped. An internal space 1s for introducing ion source gas to generate plasma is formed by the inner wall surface of the plasma generating container 1. The internal space 1s is a long space in a substantially rectangular parallelepiped shape formed in a manner extending along the long side direction of the plasma generating container 1, and is surrounded by a pair of inner wall surfaces facing each other in the extraction direction and a pair of inner wall surfaces facing each other in the width direction. In addition, the internal space is vacuum-exhausted by a vacuum exhaust device not shown.

An ion extraction port 1H, which is an opening for extracting the ion beam IB from the internal space 1s, is formed on one side wall (hereinafter referred to as the front side wall 11a) of the plasma generating container 1 parallel to the long side direction. The ion extraction port 1H is formed on the front side wall 11a in a manner extending along the long side direction, similarly to the internal space 1s. In the present embodiment, the front side wall 11a is formed to be orthogonal to the extraction direction of the ion beam IB. Hereinafter, the direction orthogonal to the extraction direction and the long side direction is referred to as the width direction. Furthermore, the so-called elongated strip shape refers to any shape formed in the following manner, that is, when observed from the lead-out direction, the length in one of the two axes that are orthogonal to each other (i.e., the length in the long side direction) is longer than the length in the other axis (i.e., the length in the width direction), and is not limited to a rectangular shape.

When observed from the long side direction, a plurality of gas introduction holes 1g are formed on two side walls (hereinafter also referred to as transverse side walls 11c and transverse side walls 11d) that are opposite to each other (opposite to each other in the width direction) sandwiching an axis (hereinafter also referred to as ion extraction axis L1) extending in the extraction direction through the ion extraction port 1H. The plurality of gas introduction holes 1g are used to connect with the gas source 5 and introduce ion source gas into the internal space 1s through a gas flow regulator (not shown). A plurality of gas introduction holes 1g are of substantially the same diameter and are provided at substantially equal intervals along the long side direction of the plasma generating container 1 near the ion introduction ports 1H of the side walls 11c and 11d (i.e., near the junction with the front wall 11a). _BF3 gas or _PH3 gas plasma source gas is introduced into the internal space 1s through the gas introduction holes 1g.

Furthermore, the plurality of gas introduction holes 1g may be formed in only one of the two transverse walls 11c and 11d, or may be arranged near the junction of the transverse wall 11c, the transverse wall 11d and the rear side wall 11b facing the front side wall 11a (i.e., near the magnetic field transmission window 3w described later). In addition, the plurality of gas introduction holes 1g may be arranged at approximately equal intervals from each other, and the hole diameters at both ends along the long side direction may be relatively larger than the hole diameter at the central portion. Alternatively, the plurality of gas introduction holes 1g may be arranged to have approximately the same hole diameter from each other, and the arrangement intervals at both ends along the long side direction may be relatively narrower than the arrangement intervals at the central portion. Furthermore, the gas introduction hole 1g is provided to open on the inner surface of the side wall of the plasma generating container 1, but may also be provided to open on the tube wall of the gas supply tube arranged in the plasma generating container 1.

A plurality of magnets 2 are arranged outside along the outer surfaces of the other side walls (specifically, the side walls 11c and 11d) other than the front side wall 11a, and a cusp magnetic field is formed near the inner surfaces of the side walls 11c and 11d. Each magnet 2 in this embodiment is a permanent magnet, but an electromagnetic magnet may also be used. The plurality of magnets 2 are arranged at approximately equal intervals in a direction orthogonal to the ion extraction direction in a manner that the polarities are different from each other. In addition, the arrangement form of the plurality of magnets 2 is not limited to this and can be appropriately changed.

The plasma generating unit 3 generates plasma by supplying a high-frequency magnetic field to the inner space 1s of the plasma generating container 1 to ionize the ion source gas.

The extraction electrode system 4 is arranged near the ion extraction port 1H of the plasma generation container 1, and accelerates and extracts the ion beam IB by providing a potential difference with the plasma generation container 1. Specifically, the extraction electrode system 4 has a plurality of plate-shaped electrodes 41 to 44 formed with slits 4x, and more specifically, as shown in FIG. 2 and FIG. 3, it has a plasma electrode 41, an extraction electrode 42, a suppression electrode 43, and a grounding electrode 44 arranged in sequence from the plasma generation container 1 toward the downstream along the ion extraction direction. Each of these electrodes has a slit 4x in the central portion thereof that penetrates in the thickness direction and extends in the long side direction. Moreover, each electrode is arranged in such a manner that the slit 4x formed in the central portion faces the ion extraction port 1H of the plasma generating container 1. Furthermore, each electrode is electrically insulated from each other by, for example, an insulator (not shown). Furthermore, the extraction electrode system 4 is preferably configured such that the slit width of the electrode closest to the plasma generating container 1 (here, the plasma electrode 41) is variable. If so, the gas pressure in the plasma chamber can be made variable, and the pressure in the plasma generating container 1 and the vacuum degree of the extraction electrode region can be set with freedom, thereby providing a margin for the withstand voltage applied between the electrodes.

Furthermore, in the ion source 100 of the present embodiment, the plasma generating unit 3 is configured to generate inductively coupled plasma in the internal space 1s of the plasma generating container 1, and includes: an antenna 31, which is arranged outside the plasma generating container 1; a high-frequency power source 32, which applies a high frequency to the antenna 31; and a magnetic field transmission window 3w, which is formed at a position facing the antenna 31 on the side wall of the plasma generating container 1, so that the high-frequency magnetic field generated by the antenna 31 is transmitted to the internal space 1s. In the above structure, by applying a high frequency from the high-frequency power source 32 to the antenna 31, a high-frequency current flows through the antenna 31, and an induced electric field is generated in the plasma generating container 1, thereby generating inductively coupled plasma.

The antenna 31 is in the shape of a straight line (specifically, a cylindrical shape) with a length of more than tens of centimeters when observed from the outside. The antenna 31 has a gap with the magnetic field transmission window 3w outside the plasma generation container 1, and is arranged straight along the long side direction of the plasma generation container 1. That is, the antenna 31 is arranged straight along the long side direction of the ion extraction port 1H or the slit 4x of the extraction electrode system 4. Moreover, when observed from the ion extraction direction, the antenna 31 is arranged at a position facing the ion extraction port 1H, more specifically, on the ion extraction axis L1. One end of the antenna 31, i.e., the power supply end, is connected to the high-frequency power supply 32 via the matching circuit 321.

The high frequency power source 32 can flow a high frequency current in the antenna 31 via the matching circuit 321. The frequency of the high frequency is, for example, 13.56 MHz in general, but is not limited thereto and can be changed appropriately.

The magnetic field transmission window 3w is formed on the side wall (referred to as the rear side wall 11b) facing the front side wall 11a of the plasma generating container 1. Specifically, as shown in FIG. 4 (a) to FIG. 4 (c), the magnetic field transmission window 3w is formed by an opening 1x provided on the rear side wall 11b of the plasma generating container 1 and a window member 33 installed on the plasma generating container 1 in a manner of blocking the opening 1x.

When viewed from the ion extraction direction, the opening 1x is in a rectangular shape in which the length along the long side direction of the plasma generating container 1 is greater than the length along the width direction. Furthermore, the opening 1x is formed in the rear wall 11b at a position facing both the antenna 31 and the ion extraction port 1H, and more specifically, is formed so as to be located on a line connecting the antenna 31 and the ion extraction port 1H.

The window member 33 includes a slit plate 331 for closing an opening 1x formed in the rear wall 11b of the plasma generating container 1 from the outside, and a dielectric plate 332 for closing a slit 331x formed in the slit plate 331 from the outside of the plasma generating container 1.

The slit plate 331 allows the high-frequency magnetic field generated by the antenna 31 to be transmitted into the plasma generating container 1, and prevents the electric field from entering the plasma generating container 1 from the outside. Specifically, the slit plate 331 is a flat plate having a plurality of slits 331x formed along the long side direction of the antenna 31 and penetrating the slit plate 331 in the thickness direction. The slit plate 331 preferably has a higher mechanical strength than the dielectric plate 332 described later, and preferably has a greater thickness than the dielectric plate 332. Furthermore, when viewed from the thickness direction, the plurality of slits 331x are parallel to each other and are formed in a manner intersecting (specifically, orthogonal to) the antenna 31. The multiple slits 331x are all of the same shape (specifically, a rectangular shape when viewed from above).

Specifically, the slit plate 331 is made of metal, and is manufactured by a metal material such as a metal selected from a group including Cu, Al, Zn, Ni, Sn, Si, Ti, Fe, Cr, Nb, C, Mo, W or Co or an alloy thereof (such as a stainless steel alloy, an aluminum alloy, etc.) through a rolling process (such as cold rolling or hot rolling).

The slit plate 331 is larger than the opening 1x of the plasma generating container 1 in a plan view, and blocks the opening 1x in a state supported by the rear side wall 11b (i.e., placed on the rear side wall 11b), and is set to the same potential as the plasma generating container 1. A sealing member such as an O-ring or a gasket is interposed between the slit plate 331 and the rear side wall 11b, and the space therebetween is vacuum-sealed.

The dielectric plate 332 is placed on the outer side of the slit plate 331 facing the outside of the plasma generating container 1 (the back side of the inner side facing the inside of the plasma generating container 1) to block the slit 331x of the slit plate 331. A sealing member is interposed between the dielectric plate 332 and the slit plate 331, and the space therebetween is vacuum-sealed.

The dielectric plate 332 as a whole includes dielectric material and is in the shape of a flat plate, for example, ceramics such as aluminum oxide, silicon carbide, and silicon nitride, inorganic materials such as quartz glass and alkali-free glass, and resin materials such as fluororesins (such as Teflon).

With the above structure, the slit plate 331 and the dielectric plate 332 function as a magnetic field transmission window 3w that transmits the magnetic field generated by the antenna 31. That is, when a high frequency is applied to the antenna 31 from the high frequency power source 32, the high frequency magnetic field generated by the antenna 31 transmits the magnetic field transmission window 3w including the slit plate 331 and the dielectric plate 332 and is formed (supplied) in the plasma generation container 1. Thereby, an induced electric field is generated in the space in the plasma generation container 1, thereby generating inductively coupled plasma.

Moreover, in the plasma processing apparatus of the present embodiment, the window member 33 further includes a mask plate 333 that covers each slit 331x formed in the slit plate 331 with a gap from the inner side of the plasma generating container 1.

To explain more specifically, the shield plate 333 is a flat plate having a plurality of slits 333x formed along the long side direction of the antenna 31 and extending through the shield plate 333 in the thickness direction. When viewed from the thickness direction, the plurality of slits 333x are parallel to each other and are formed in parallel with the plurality of slits 331x formed in the slit plate 331. Here, each slit 333x is formed in a manner intersecting (specifically, orthogonal to) the antenna 31. The plurality of slits 333x are all formed in the same shape (specifically, a rectangular shape when viewed from above).

A beam-shaped region 333z parallel to each slit 333x is formed between adjacent slits 333x in the mask plate 333. A plurality of beam-shaped regions 333z are formed in a manner corresponding to the plurality of slits 331x formed in the slit plate 331, and each beam-shaped region 333z covers each slit 331x of the slit plate 331. Here, the length (width) of the beam-shaped region 333z along the long side direction of the antenna 31 is substantially the same as the width of the slit 331x of the slit plate 331, and each beam-shaped region 333z covers substantially all of each slit 331x of the slit plate 331. Each beam-shaped region 333z may also be formed in a manner of covering only a portion of each slit 331x. Furthermore, the mask plate 333 is connected to the inner surface of the slit plate 331 and is set to the same potential.

Specifically, the mask plate 333 includes a metal material such as a metal selected from the group consisting of Cu, Al, Zn, Ni, Sn, Si, Ti, Fe, Cr, Nb, C, Mo, W, or Co, or an alloy thereof (such as a stainless steel alloy, an aluminum alloy, etc.). The thickness of the mask plate 333 is preferably smaller than the thickness of the slit plate 331.

In addition, in the embodiment, a flow path 331r for a cooling medium such as water to flow is formed in the slit plate 331. The flow path 331r is formed along the long side direction of the antenna 31 near the connection area of the mask plate 333 in the slit plate 331. Here, the flow path 331r is formed in a manner to be located directly above the connection area along the thickness direction of the slit plate 331.

In addition, in the ion source 100 of the present embodiment, the distance between the inward surface of the magnetic field transmission window 3w (specifically, the inward surface of the slit plate 331) and the surface of the electrode of the extraction electrode system 4 closest to the plasma generating container 1 is preferably set to a range of about 45 mm to about 140 mm.

In addition, in the ion source 100 of the present embodiment, as shown in FIG2 and FIG3, a discharge electrode 7 is provided near the ion extraction port 1H in the internal space of the plasma generation container 1. The discharge electrode 7 generates a direct current discharge or a low frequency discharge between the discharge electrode 7 and the electrode (here, the plasma electrode 41) closest to the plasma generation container 1 in the extraction electrode system 4 using the plasma formed in the internal space 1s by inductive coupling, thereby increasing the density of the plasma generated near the ion extraction port 1H in the internal space 1s.

The discharge electrode 7 of this embodiment is a rod-shaped or straight-tube-shaped metal electrode, and is disposed in parallel along the long-side direction at a position facing the ion extraction port 1H in the internal space 1s (specifically, also referred to as a line connecting the antenna 31 and the ion extraction port 1H or an ion extraction axis L1). That is, the discharge electrode 7 is arranged so as to coincide with the long-side direction of the slit 4x formed in the electrodes 41 to 44 constituting the extraction electrode system 4.

When the discharge electrode 7 is in a rod shape, it is preferably made of a high melting point material such as tungsten. In addition, when the discharge electrode 7 is in a tubular shape, it is preferably made of a stainless steel tube, an aluminum (or aluminum alloy) tube, a copper (or copper alloy) tube, etc., and a flow path for cooling fluid to flow is formed inside.

A negative direct current voltage may be applied to the discharge electrode 7 relative to the electrode (plasma electrode 41) closest to the plasma generation container 1 in the extraction electrode system 4, or an alternating voltage with a frequency of about 10 kHz or less may be applied. In addition, the plasma generation container 1 and the plasma electrode 41 may be short-circuited or connected via a resistor. Alternatively, a positive voltage may be applied to the plasma generation container 1 relative to the plasma electrode 41 using a direct current power source.

<Effects of the present embodiment> According to the ion source 100 of the present embodiment constructed in this way, plasma is generated in the inner space 1s by the antenna 31 provided outside the plasma generating container 1 without using a filament protruding into the inner space 1s of the plasma generating container 1, thereby reducing the parts consumed by sputtering in the plasma generating container 1, thereby extending the maintenance cycle. In addition, a roughly uniform plasma can be generated in the inner space 1s by an antenna 31 extending in the direction of the ion extraction port and a high-frequency power supply 32, thereby significantly reducing the number of parts, miniaturizing the device, and reducing the processing time required for installation or the number of power supply control points, thereby suppressing the manufacturing cost. Furthermore, by reducing the number of power sources, the wires for power supply and the control wires of the equipment can be greatly reduced, thereby simplifying the wiring work during assembly and the disassembly work during maintenance, and improving the workability. Furthermore, by setting the discharge electrode 7 near the ion extraction port 1H, the plasma generated in the internal space 1s can be used to generate direct current discharge or low-frequency discharge between the extraction electrode system 4 (specifically, the electrode 41 closest to the ion extraction port 1H), thereby increasing the plasma density generated near the ion extraction port 1H.

Here, in the case of a large ion source or a strip ion source having a large area, the pressure (vacuum degree) in the plasma chamber and the vacuum degree in the region of the extraction electrode system 4 to which a high voltage is applied are approximately equal because there is no pressure difference due to the large slit conductance of the slit 4x of the extraction electrode system 4. On the other hand, in order to stably apply a high voltage to the extraction electrode system 4, the pressure in the region where the extraction electrode system 4 is installed needs to be set to about 1 mTorr (about 133 mPa) as the upper limit. Under such pressure conditions, when a parallel plate electrode unit arranged at a distance of about several millimeters to about ten millimeters corresponding to the slit 4x of the lead electrode system 4 is used as the plasma generating unit 3, plasma cannot be generated by direct current voltage, and plasma cannot be generated even by normal high-frequency discharge. On the other hand, according to the ion source 100 of this embodiment, at such a low pressure near the lower limit of the discharge capability of the inductively coupled discharge, a plasma-ignited species (species plasma) based on high-frequency plasma can be supplied between the discharge electrode 7 and the extraction electrode system 4, and on the other hand, the plasma density can be increased by using direct current discharge or alternating voltage (high-frequency voltage) of the species plasma, thereby efficiently extracting an ion beam without using a filament. Furthermore, when a parallel plate electrode is used as the plasma generating unit 3, it is almost impossible to adjust the necessary position of the distance between electrodes in a vacuum. However, in the ion source 100 of this embodiment, by using an external antenna 31 as the plasma generating unit 3, the plasma distribution can be adjusted based on the distribution of the species plasma. Therefore, it can be said that the combination of the external antenna 31 and the discharge electrode 7 in a vacuum is a very effective structure.

<Other variant implementation forms> Furthermore, the present invention is not limited to the above-mentioned implementation forms.

For example, as shown in FIG5(a), another embodiment of the ion source 100 may also include a distance adjustment mechanism 6 for adjusting the distance between the antenna 31 and the magnetic field transmission window 3w. The distance adjustment mechanism 6 is configured to partially adjust the distance between the antenna 31 and the magnetic field transmission window 3w by adjusting the positions of multiple parts of the antenna 31. Specifically, the distance adjustment mechanism 6 is configured to be able to adjust the position of a part or multiple parts of the antenna 31 along the long side direction.

To explain more specifically, the distance adjustment mechanism 6 includes: an antenna supporting member 61, which is arranged on the upper surface of the window member 33 and supports the two ends of the antenna 31; a plurality of holding parts 62, which hold a plurality of parts of the antenna 31 and shift the held parts relative to the magnetic field transmission window 3w (specifically, the dielectric plate 332); and a driving source (not shown) such as a motor that moves the holding parts 62 independently.

The plurality of gripping parts 62 are insulators electrically insulated from the antenna 31. One of the gripping parts 62 is disposed just above the center of the opening 1x of the plasma generating container 1, and other gripping parts 62 are disposed at symmetrical positions relative to the gripping part 62 along the long side direction of the antenna 31. In addition, in the present embodiment, the plurality of gripping parts 62 are disposed at equal intervals, and when viewed from a direction orthogonal to the opening 1x of the plasma generating container 1, they are all disposed on the inner side of the opening 1x.

Specifically, the gripping portion 62 includes: a pressing clamp 621 for pressing the side of the antenna 31 toward the window member 33; and a gap adjusting clamp 622 provided to be supported between the antenna 31 and the window member 33. The pressing clamp 621 is configured to always press the antenna 31 toward the window member 33 using, for example, a spring material. The gap adjusting clamp 622 is configured to be able to adjust the length along the thickness direction of the window member 33. Here, the gap adjusting clamp 622 is a clamp having an elliptical cross-section, and is configured to change the length along the thickness direction by rotating, thereby adjusting the distance between the antenna 31 and the window member 33.

In addition, in the ion source 100 of the embodiment, the mask plate 333 is formed with a plurality of slits 333x, and the slits 331x of the slit plate 331 are covered by beam-shaped regions 333z formed between the plurality of slits 333x, but the present invention is not limited thereto. As shown in (b) of FIG. 5 , the mask plate 333 of another embodiment may also be formed of a strip-shaped metal plate. In this case, one or more mask plates 333 may be provided at positions facing each of the plurality of slits 331x formed in the slit plate 331. In the case where a plurality of mask plates 333 are provided for one slit 331x, it is preferred that the mask plates 333 be arranged so as to have different heights in the thickness direction.

In addition, another embodiment of the ion implantation device 400 may also be configured to adjust the distance between the antenna 31 and the magnetic field transmission window 3w, or the output of the high-frequency power supply 32, according to the current value of the introduced ion beam IB. Specifically, as shown in FIG6 , the ion implantation device 400 includes a current distribution monitor for monitoring the current distribution of the ion beam IB along the long side direction at the rear end of the mass analysis magnet 210, and is configured to compare the monitored current distribution of the ion beam IB with the target value of the average current density or uniformity through a comparison operator, and adjust the distance between the antenna 31 and the magnetic field transmission window 3w, or the output of the high-frequency power supply 32 according to the comparison result.

In addition, in the embodiment, the discharge electrode 7 is in a rod or straight tube shape, but is not limited to this. As shown in FIG7 , the discharge electrode 7 of another embodiment may also include a pair of plate-shaped electrodes that are arranged opposite to each other and are parallel to each other with the ion extraction axis L1 sandwiched therebetween. In this case, it is preferred to apply an alternating voltage of a frequency of about 10 kHz or less to the discharge electrode 7 with the plasma generation container 1 as a reference potential. Moreover, in this case, it is preferred to include a shielding member 71 that covers the back and side surfaces (side surfaces other than the surfaces facing each other) of the discharge electrode 7. The shielding member 71 is used to prevent unnecessary discharge caused by voltage between the discharge electrode 7 and the inner wall surface of the plasma generation container 1. The shielding member 71 is preferably made of a material having excellent heat resistance, workability, and corrosion resistance based on gas species, such as preferably stainless steel, tungsten, molybdenum, tantalum, or an alloy containing any of these, but not limited to these. By including such a shielding member 71, the discharge between the pair of discharge electrodes 7 can be effectively utilized.

In addition, in the above-mentioned embodiment, the magnetic field transmission window 3w is formed on the rear side wall 11b of the plasma generating container 1, but the present invention is not limited thereto. For example, in another embodiment, when viewed from the long side direction, the magnetic field transmission window 3w may also be formed on one or both of the two side walls (lateral side wall 11c, lateral side wall 11d) facing each other with the ion extraction axis L1 sandwiched therebetween.

In addition, in the ion source 100 of the embodiment, the high-frequency power supply 32 and the matching circuit 321 are set in the high-voltage part, but the present invention is not limited to this. In another embodiment of the ion source 100, the high-frequency power supply 32 and the matching circuit 321 can also be set to the ground potential, which can help reduce the capacity of the insulating transformer used to supply power to the high-voltage part, thereby helping to miniaturize the entire system, reduce costs, and avoid equipment failures caused by discharge failures due to high voltage.

In addition, the antenna 31 may also be a hollow structure component having a flow path for cooling liquid to flow therein. In addition, the antenna 31 may also be a so-called inductor capacitor (LC) antenna 31 including the following components, namely, at least two conductor components and a capacitor as a quantitative element electrically connected in series with adjacent conductor components. For example, the antenna 31 includes three conductor components and two capacitors, and each conductor component may also be a component of the same shape having a straight flow path for cooling liquid to flow therein and in a straight tube shape (specifically, a round tube shape). The material of each conductor component may be, for example, copper, aluminum, alloys thereof, or metals such as stainless steel.

By configuring the antenna 31 in this way, the composite reactance of the antenna 31 is simply the inductive reactance minus the capacitive reactance, so it is possible to reduce the impedance of the antenna 31. As a result, even when the antenna 31 is extended, the increase in its impedance can be suppressed, and high-frequency current can easily flow through the antenna 31, so that inductively coupled plasma can be efficiently generated in the internal space 1s.

In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the invention.

Furthermore, the disclosure of this specification may include the following Form 1-Form 6.

(Form 1) An ion source, comprising: a plasma generating container, which is a container having an inner space for introducing an ion source gas, and an ion introduction port formed on one side wall thereof; a plasma generating unit, which ionizes the ion source gas to generate plasma in the inner space, and comprises an antenna and a magnetic field transmission window, wherein the antenna is arranged outside the plasma generating container and connected to a high frequency power source to generate a high frequency magnetic field. The invention relates to a plasma generating container comprising a discharge electrode system, a discharge electrode system and an extraction electrode system. The discharge electrode system comprises a discharge electrode system and an extraction electrode system. The discharge electrode system comprises a discharge electrode system and an extraction electrode system. The discharge electrode system comprises a discharge electrode system and an extraction electrode system. The discharge electrode system comprises a discharge electrode system and an extraction electrode system. The discharge electrode system comprises a discharge electrode system and an extraction electrode system. The discharge electrode system comprises a discharge electrode system and an extraction electrode system. The discharge electrode system comprises a discharge electrode system and an extraction electrode system. The discharge electrode system comprises a discharge electrode system and an extraction electrode system. The discharge electrode system comprises a discharge electrode system and an extraction electrode system. The discharge electrode system comprises a discharge electrode system and an extraction electrode system. The discharge electrode system comprises a discharge electrode system and a discharge ...

In this form, plasma is generated in the inner space of the plasma generating container by an antenna provided outside the plasma generating container without using a filament protruding into the inner space of the plasma generating container, thereby reducing the number of parts consumed by sputtering in the plasma generating container and extending the maintenance cycle. In addition, a roughly uniform plasma can be generated in the inner space by an antenna extending in the direction of the ion extraction port and a high-frequency power supply, thereby significantly reducing the number of parts, miniaturizing the device, and reducing the processing time required for installation or the number of power supply control points, thereby suppressing the manufacturing cost. Furthermore, by reducing the number of power sources, the number of power supply wires and equipment control wires can be greatly reduced, thereby simplifying the wiring work during assembly and the disassembly work during maintenance, and improving workability. Furthermore, by setting a discharge electrode near the ion extraction port, the plasma generated in the internal space can be used to generate direct current discharge or low-frequency discharge between the extraction electrode system, thereby increasing the plasma density generated near the ion extraction port.

(Form 2) An ion source as described in Form 1, wherein the plasma generation container is in the shape of an elongated strip, the ion extraction port is formed on the one side wall along the long side direction thereof, the extraction electrode system includes one or more plate-shaped electrodes arranged at positions facing the ion extraction port, and slits are formed along the long side direction at positions of each electrode corresponding to the ion extraction port and extending along the thickness direction of each electrode, and the antenna and the discharge electrode are in the shape of being elongated along the long side direction. In this configuration, by making the direction in which the antenna and discharge electrode are extended and the direction in which the slit of the extraction electrode system is extended all coincide with each other in the long-side direction, plasma can be efficiently generated near the ion extraction port using plasma species generated by high-frequency electricity flowing in the antenna.

(Form 3) The ion source as described in Form 2, wherein the discharge electrode is arranged on a line connecting the antenna and the ion extraction port when viewed from the long side. In this form, plasma can be efficiently generated by a simple structure using one discharge electrode.

(Form 4) An ion source as described in Form 2 or 3, wherein the discharge electrode is a tubular member having a flow path for cooling fluid to flow therein. In this form, by flowing the cooling fluid, deformation caused by a temperature rise of the discharge electrode can be suppressed, the distance between the discharge electrode and peripheral structures such as an extraction electrode can be stably maintained, plasma can be stably generated, and plasma distribution can be stabilized.

(Form 5) The ion source as described in Form 2, wherein, when viewed from the long side direction, the discharge electrode includes a pair of plate electrodes, and the pair of plate electrodes are arranged facing each other with the line connecting the antenna and the ion extraction port sandwiched therebetween. In this form, by arranging the pair of plate electrodes so as to sandwich the ion extraction port, a high-density region of the generated high-frequency plasma can be set near the ion extraction port, and plasma can be efficiently generated between the electrodes sandwiching the ion extraction port.

(Form 6) An ion source as described in Form 5, wherein a shielding member is arranged on the back side of each of the pair of plate-like electrodes, and the shielding member suppresses discharge between the back side of the plate-like electrode and the inner wall of the plasma generating container. Since the plasma generated near the ion extraction port is extracted as an ion beam, it is preferable to efficiently generate plasma at the position. By providing a shielding member on the back side of the plate-like electrode (i.e., the back side of the surfaces facing each other), unnecessary plasma generation between the plate-like electrode and the inner wall of the plasma generating container can be suppressed, and electric power can be effectively used to efficiently generate plasma near the ion extraction port.

1: Plasma generation container 1g: Gas inlet hole 1H: Ion extraction port 1s: Internal space 1x: Opening 2: Magnet 3: Plasma generation unit 3w: Magnetic field transmission window 4: Extraction electrode system 4x: Slit 5: Gas source 6: Distance adjustment mechanism 7: Discharge electrode 11a: Side wall (front side wall) 11b: Rear side wall 11c, 11d: Horizontal side wall 31: Antenna 32: High-frequency power supply 33: Window member 41: Plasma electrode (plate electrode) (electrode) 42: Extraction electrode (plate electrode) (electrode) 43: Suppression electrode (plate electrode) (electrode) 44: Grounding electrode (plate electrode) (electrode) 61: Antenna support member 62: Holding part 71: Shielding member 100: Ion source 200: Mass analysis part 210: Mass analysis magnet 211: Slit plate 220: Analysis slit 300: Processing chamber 310: Substrate drive device 321: Matching circuit 331: Slit plate 331r: Flow path 331x: Slit 332: Dielectric plate 333: Shield plate 333x: Slit 333z: Beam region 400: Ion implantation device 621: Pressing fixture 622: Gap adjustment fixture IB: Ion beam L1: Ion extraction axis W: Substrate

FIG1 is a schematic diagram showing the overall structure of an ion implantation device of an embodiment of the present invention. FIG2 is a cross-sectional diagram schematically showing the structure of an ion source of the embodiment. FIG3 is a longitudinal cross-sectional diagram schematically showing the structure of an ion source of the embodiment. FIG4 (a) to FIG4 (c) are diagrams schematically showing the structure of a window member of the embodiment, FIG4 (a) is a cross-sectional diagram, FIG4 (b) is a plan view observed from the antenna side, and FIG4 (c) is a plan view observed from the inner space side. FIG. 5 (a) and FIG. 5 (b) are diagrams schematically showing the structure of a window member of another embodiment, FIG. 5 (a) is a cross-sectional view, and FIG. 5 (b) is a plan view observed from the inner space side. FIG. 6 is a diagram for explaining the function of a current distribution monitor of an ion injection device of another embodiment. FIG. 7 is a longitudinal cross-sectional view schematically showing the structure of an ion source of another embodiment.

1: Plasma generation container

1g: Gas inlet hole

1H: ion extraction port

1s: Internal space

1x: Open

2: Magnet

3: Plasma generation unit

3w: Magnetic field transmission window

4: Lead out electrode system

4x: Narrow seam

7: Discharge electrode

11a: Side wall (front side wall)

11b: posterior wall

11c, 11d: lateral wall

31: Antenna

32: High frequency power supply

33: Window components

41: Plasma electrode (plate electrode) (electrode)

42: Lead-out electrode (plate electrode) (electrode)

43: Suppression electrode (plate electrode) (electrode)

44: Ground electrode (plate electrode) (electrode)

100:Ion source

321: Matching circuit

331: Slit board

332: Dielectric board

333: Masking board

IB: Ion beam

L1: ion extraction axis

Claims (6)

An ion source comprises: A plasma generating container, which is a container having an internal space for introducing ion source gas, and an ion introduction port is formed on one side wall thereof; A plasma generating unit, which ionizes the ion source gas to generate plasma in the internal space, and comprises an antenna and a magnetic field transmission window, The antenna is arranged outside the plasma generating container and connected to a high-frequency power source to generate a high-frequency magnetic field, The magnetic field transmission window is formed at a position of the side wall of the plasma generating container facing the antenna, so that the high-frequency magnetic field generated by the antenna is transmitted to the internal space; A discharge electrode is arranged near the ion introduction port in the internal space; and The extraction electrode system is arranged outside the plasma generation container, and extracts the ion beam from the internal space through the ion extraction port. The ion source as described in claim 1, wherein the plasma generation container is in the shape of an elongated strip, and the ion extraction port is formed on the one side wall along the long side direction thereof; The extraction electrode system includes one or more plate-shaped electrodes arranged at a position facing the ion extraction port, and a slit is formed along the long side direction at a position of each electrode corresponding to the ion extraction port and extending along the thickness direction of each electrode; The antenna and the discharge electrode are in a shape extending along the long side direction. The ion source as described in claim 2, wherein the discharge electrode is arranged on a line connecting the antenna and the ion extraction port when viewed from the long side direction. The ion source according to claim 2 or 3, wherein the discharge electrode is a tubular member having a flow path for a cooling fluid to flow formed therein. The ion source as described in claim 2, wherein, when viewed from the long side direction, the discharge electrode includes a pair of plate electrodes, and the pair of plate electrodes are arranged to face each other with a line connecting the antenna and the ion extraction port interposed therebetween. The ion source as described in claim 5, wherein a shielding member is arranged on the back side of each of the pair of plate-shaped electrodes, and the shielding member suppresses discharge between the back side of the plate-shaped electrode and the inner wall of the plasma generating container.