Patent Application
20230260747
The content of Japanese Patent Application No. 2022-021334, on the basis of which priority benefits are claimed in an accompanying application data sheet, is in its entirety incorporated herein by reference.
Certain embodiments of the present invention relate to an ion implanter and an ion implantation method.
The related art discloses an ion implanter including a beam blocking mechanism capable of blocking an ion beam before a wafer is irradiated. The beam blocking mechanism includes a pair of shutter plates driven to be opened and closed by a motor and is switchable between a closed state in which the ion beam is physically blocked and an open state in which the ion beam passes, depending on the opening width thereof. The beam blocking mechanism is brought into the closed state when the wafer is moved to an ion implantation position, switched to the open state when ions are implanted into the wafer, and is switched to the closed state again when the wafer is moved from the ion implantation position.
According to an embodiment of the present invention, there is provided an ion implanter including a beam deflection device that deflects an ion beam by at least one of an electric field and a magnetic field, and that is switchable between an irradiation-enabled state in which the ion beam is directed in an irradiation-enabled direction in which a workpiece is capable of being irradiated with the ion beam, and an irradiation-disabled state in which the ion beam is directed in an irradiation-disabled direction in which the workpiece is incapable of being irradiated with the ion beam; a holding device that holds the workpiece to be irradiated with the ion beam; a transfer device that transfers the workpiece to or from the holding device; a processor that controls the beam deflection device, the holding device, and the transfer device; and a memory in which a program is stored. On the basis of the program, the processor executes (a) switching the beam deflection device to the irradiation-disabled state after a first workpiece held on the holding device is irradiated with the ion beam; (b) releasing the holding of the first workpiece on the holding device, subsequently to the step (a); (c) transferring the first workpiece from the holding device with the transfer device, subsequently to the step (b); (d) transferring a second workpiece different from the first workpiece to the holding device with the transfer device, subsequently to the step (c); (e) holding the second workpiece on the holding device, subsequently to the step (d); and (f) switching the beam deflection device to the irradiation-enabled state, subsequently to the step (e).
According to another embodiment of the present invention, there is provided an ion implantation method. The method includes (a) deflecting an ion beam by at least one of an electric field and a magnetic field in an irradiation-disabled direction in which a workpiece is incapable of being irradiated with the ion beam after a first workpiece is irradiated with the ion beam directed in an irradiation-enabled direction in which the workpiece is capable of being irradiated with the ion beam; (b) moving the first workpiece from an ion implantation position, subsequently to the step (a); (c) disposing a second workpiece different from the first workpiece at the ion implantation position, subsequently to the step (b); and (d) returning the ion beam from the irradiation-disabled direction to the irradiation-enabled direction, subsequently to the step (c).
In the ion implanter of the related art, the beam blocking mechanism is switched between the closed state and the open state each time a wafer serving as an ion implantation target is replaced. However, for the beam blocking mechanism that is physically driven to be opened and closed by the motor, it takes substantial time to perform the operation of opening and closing the pair of shutter plates. Therefore, the wafer replacement time becomes long.
It is desirable to provide an ion implanter or the like capable of shortening a replacement time of workpieces.
In this aspect, since the irradiation-disabled state during the workpiece replacement in the steps (b) to (e) and the irradiation-enabled state when the workpiece is irradiated with the ion beam can be quickly switched therebetween by the beam deflection device that deflects the ion beam by at least one of an electric field and a magnetic field, the replacement time of the workpieces can be shortened.
In addition, optional combinations of the above components or those obtained by exchanging the expressions of the present invention with each other between methods, devices, systems, recording media, computer programs, and the like are also effective as aspects of the present invention.
Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the descriptions or drawings, the same or equivalent components, members, and processing are designated by the same reference numerals, and redundant descriptions will be omitted. The scales and shapes of the respective parts shown in the drawings are set for convenience in order to facilitate the descriptions, and should not be interpreted as limiting unless otherwise specified. The embodiments are merely examples and do not limit the scope of the present invention. All the features and combinations to be described in the embodiments are not necessarily essential to the invention.
The ion implanter 10 can irradiate the entire processing surface of the wafer W with an ion beam by causing an ion beam to perform reciprocating scanning in one direction (hereinafter, also referred to as a scanning direction, a beam scanning direction, or a beam movement direction) and reciprocating the wafer W in a direction (hereinafter, also referred to as a reciprocating motion direction, a reciprocating movement direction, or a wafer movement direction) perpendicular to the scanning direction. In the present specification, a traveling direction (hereinafter, also referred to as a beam traveling direction) of an ion beam which travels along a designed beamline A is defined as a z direction, and a plane perpendicular to the z direction is defined as an xy plane. In a case where the workpiece W is scanned with the ion beam, the scanning direction (beam movement direction) of the ion beam is defined as an x direction, and a y direction perpendicular to the z direction and the x direction is defined as the wafer movement direction. In this way, the reciprocating scanning with the ion beam is performed in the x direction, and the reciprocating motion of the wafer W is performed in the y direction.
The ion implanter 10 includes an ion generation device 12, a beamline unit 14, an implantation processing chamber 16, and a wafer transfer device 18. The ion generation device 12 supplies an ion beam to the beamline unit 14. The beamline unit 14 transports the ion beam supplied from the ion generation device 12 to the implantation processing chamber 16. The wafer W serving as an ion implantation target is accommodated in the implantation processing chamber 16, and ion implantation processing is performed in which the wafer W is irradiated with an ion beam supplied from the beamline unit 14. The wafer transfer device 18 serving as a transfer device transfers an unprocessed wafer before the ion implantation processing into the implantation processing chamber 16 and transfers a processed wafer after the ion implantation processing from the implantation processing chamber 16. In addition, although not shown, the ion implanter 10 is provided with an evacuating system for providing desired vacuum environments to the ion generation device 12, the beamline unit 14, the implantation processing chamber 16, and the wafer transfer device 18.
The beamline unit 14 includes a mass analyzing unit 20, a beam park device 24, a beam shaping unit 30, a beam scanning device 32, a beam parallelizing unit 34, and an angular energy filter (AEF) 36 in order from an upstream side of the beamline A. In addition, the upstream (side) of the beamline A is a side closer to the ion generation device 12, and the downstream (side) of the beamline A is a side closer to the implantation processing chamber 16 (or a beam stopper 46).
The mass analyzing unit 20 provided downstream of the ion generation device 12 selects or extracts desired ion species to be used for the ion implantation processing from the ion beam generated by the ion generation device 12 through mass analysis. The mass analyzing unit 20 includes a mass analyzing magnet 21, a mass analyzing lens 22, and a mass analyzing slit 23.
The mass analyzing magnet 21 applies a magnetic field to the ion beam extracted from the ion generation device 12 and deflects the ion beam to travel in different trajectories depending on the value of a mass-to-charge ratio M = m/q (m is mass and q is a charge) of ions. The mass analyzing magnet 21, for example, applies a magnetic field in the -y direction to the ion beam to deflect the ion beam in the x direction. The magnetic field intensity of the mass analyzing magnet 21 is adjusted such that ion species having a desired mass-to-charge ratio M can pass through the downstream mass analyzing slit 23.
The mass analyzing lens 22 is provided downstream of the mass analyzing magnet 21 (and upstream of the mass analyzing slit 23), and adjusts a focusing power/defocusing power (or the degree of convergence/degree of defocusing of the ion beam) with respect to the ion beam. The mass analyzing lens 22 adjusts the focusing position of the ion beam passing through the mass analyzing slit 23 in a beam traveling direction (z direction) and adjusts the mass resolution M/dM of the mass analyzing unit 20. In addition, the mass analyzing lens 22 may not be provided in the mass analyzing unit 20.
The mass analyzing slit 23 is provided at a downstream position away from the mass analyzing lens 22. The mass analyzing slit 23 has a rectangular opening 23a having a relatively short width in the x direction and a relatively long height in the y direction. Since the width direction (x direction) of the opening 23a coincides with a beam deflection direction (x direction) by the mass analyzing magnet 21, the width (dimension in the x direction) of the opening 23a mainly contributes to the selection of desired ion species according to the mass-to-charge ratio M in the mass analyzing slit 23.
The mass analyzing slit 23 may make the slit width (the width of the opening 23a) variable in order to adjust the mass resolution. For example, the slit width may be adjusted by configuring the mass analyzing slit 23 with two shield members that are relatively movable in the slit width direction (x direction) and changing the distance between the two shield members in the slit width direction. Additionally, the mass analyzing slit 23 may change the slit width by switching between a plurality of slits having different slit widths.
The beam park device 24 constitutes a beam deflection device that deflects the ion beam by at least one of an electric field and a magnetic field. Specifically, the beam park device 24 is switchable between an irradiation-enabled state in which the ion beam is directed in an irradiation-enabled direction in which the wafer W can be irradiated with the ion beam and an irradiation-disabled state in which the ion beam is directed in an irradiation-disabled direction in which the wafer W cannot be irradiated with the ion beam. In the example of
The beam park device 24 in the irradiation-disabled state temporarily retracts the ion beam from the beamline A and shields the ion beam directed to the downstream implantation processing chamber 16 (or wafer W) with the beam dump 26. That is, the ion beam directed in the irradiation-disabled direction collides with the beam dump 26 outside the opening 23a of the mass analyzing slit 23 and is blocked. The beam park device 24 can be disposed at an optional position on the beamline A but is disposed between the mass analyzing lens 22 and the mass analyzing slit 23 in the shown example. As mentioned above, since a certain distance or more is required between the mass analyzing lens 22 and the mass analyzing slit 23, the space can be efficiently used by disposing the beam park device 24 between the mass analyzing lens 22 and the mass analyzing slit 23. As a result, the beamline A can be shortened, and the entire ion implanter 10 can be downsized as compared to a case where the beam park device 24 is disposed at another location.
The beam park device 24 shown in
In the example of
In the above example, during the non-deflection of the ion beam in which no voltage is applied to the pair of park electrodes 25a and 25b, the ion beam travels in the irradiation-enabled direction, and during the deflection of the ion beam in which a voltage is applied to the pair of park electrodes 25a and 25b, the ion beam travels in the irradiation-disabled direction. However, the ion beam during the non-deflection may travel in the irradiation-disabled direction, and the ion beam during the deflection may travel in the irradiation-enabled direction. In this case, for example, the beam dump 26 may be provided at the position of the opening 23a of the mass analyzing slit 23 in
Additionally, the ion beam traveling in the irradiation-enabled direction and the ion beam traveling in the irradiation-disabled direction may be deflected by different voltages applied to the pair of park electrodes 25a and 25b. For example, in a case where the irradiation-enabled direction (the direction in which the opening 23a of the mass analyzing slit 23 is located) forms a first deflection angle Θ1 with respect to an incident direction of the ion beam into the beam park device 24, and the irradiation-disabled direction (the direction in which the beam dump 26 is located) forms a second deflection angle Θ2 that is significantly different from the first deflection angle Θ1 with respect to the incident direction of the ion beam into the beam park device 24, the direction in which the beam of the desired ion species travels is switched between the irradiation-enabled direction and the irradiation-disabled direction by switching the voltage to be applied to the pair of park electrodes 25a and 25b between a first voltage V1 that realizes the first deflection angle Θ1 and a second voltage V2 (≠ V1) that realizes the second deflection angle Θ2.
As described above, the facing direction of the pair of park electrodes 25a and 25b is the y direction and is perpendicular to the beam deflection direction (x direction) of the mass analyzing magnet 21. For this reason, the deflection voltage in the y direction to be applied between the pair of park electrodes 25a and 25b does not hinder the selection of the desired ion species according to the mass-to-charge ratio M performed in the x direction by the mass analyzing magnet 21.
In the example of
The beam park device 24 includes the pair of magnetic poles 25c and 25d that faces each other in the x direction with the ion beam IB interposed therebetween. Each of the magnetic poles 25c and 25d is a core of a magnetic material such as iron, and coils 25e and 25f are wound around the outer peripheries of the cores. The magnetic poles 25c and 25d and the coils 25e and 25f constitute an electromagnet that causes a magnetic field change in the x direction by changing an electric current to be applied to the coils 25e and 25f. Since the ion beam IB traveling in the z direction receives a Lorentz force in the -y direction due to the magnetic field in the x direction between the magnetic poles 25c and 25d, the traveling direction of the ion beam IB is switchable between the irradiation-enabled direction D1 and the irradiation-disabled direction D2 similarly to
In the example of
In the above example, during the non-deflection of the ion beam in which no magnetic field is applied between the pair of magnetic poles 25c and 25d, the ion beam travels in the irradiation-enabled direction, and during the deflection of the ion beam in which a magnetic field is applied between the pair of magnetic pole 25c and 25d, the ion beam travels in the irradiation-disabled direction. However, the ion beam during the non-deflection may travel in the irradiation-disabled direction, and the ion beam during the deflection may travel in the irradiation-enabled direction. Additionally, the ion beam traveling in the irradiation-enabled direction and the ion beam traveling in the irradiation-disabled direction may be deflected by different magnetic fields applied between the pair of magnetic poles 25c and 25d.
In addition, instead of or in addition to the beam park device 24 according to the embodiment of
Hereinafter, the various beam park devices 24 as mentioned above, the mass analyzing magnet 21 in the mass analyzing unit 20 functioning as the beam deflection device, and the like will be collectively referred to as the beam deflection device 24.
In
The injector Faraday cup 28 measures the beam current of the ion beam mass-analyzed by the mass analyzing unit 20. By measuring the beam current while changing the magnetic field intensity of the mass analyzing magnet 21, the injector Faraday cup 28 can acquire the mass analysis spectrum of the ion beam. This mass analysis spectrum is used, for example, to calculate the mass resolution of the mass analyzing unit 20.
The beam blocking mechanism in
A beam blocking mechanism in
A beam blocking mechanism in
A beam blocking mechanism in
A beam blocking mechanism of
Hereinafter, the beam blocking mechanisms of
In
The beam scanning device 32 performs reciprocating scanning by at least one of an electric field and a magnetic field in a predetermined scanning angle range in the x direction with an ion beam (shaped by the beam shaping unit 30) with which the wafer W is irradiated. As will be described below, the beam scanning device 32 can also be used as a beam deflection device that deflects the ion beam between the irradiation-enabled direction and the irradiation-disabled direction instead of or in addition to the beam park device 24. The beam scanning device 32 includes a pair of scanning electrodes that faces each other in a beam scanning direction (x direction). The pair of scanning electrodes is connected to a variable voltage power supply (not shown), and a voltage to be applied between the pair of scanning electrodes is periodically changed to change an electric field between the electrodes such that the ion beam is deflected at various angles in a zx plane. As a result, the entire scanning range in the x direction is scanned with the ion beam. In
The beam parallelizing unit 34 adjusts the traveling directions of the ion beam scanned by the beam scanning device 32 to be substantially parallel to the trajectory of the designed beamline A. The beam parallelizing unit 34 includes a plurality of arc-shaped parallelizing lens electrodes in each of which an ion beam passing slit is provided at a central portion in the y direction. The parallelizing lens electrodes are connected to a high-voltage power supply (not shown), and an electric field generated by the applied voltage is made to act on the ion beam to align the traveling directions of the ion beam substantially parallel to the beamline A. In addition, the beam parallelizing unit 34 may be replaced with another type of beam parallelizing device, for example, a magnetic device using a magnetic field. Additionally, an acceleration/deceleration (AD) column (not shown) for accelerating or decelerating the ion beam may be provided downstream of the beam parallelizing unit 34.
The angular energy filter (AEF) 36 analyzes the energy of the ion beam and deflects the ions of having required energy downward (-y direction) at a prescribed angle to guide the ions to the implantation processing chamber 16. The angular energy filter 36 includes an AEF electrode pair for electric field deflection connected to a high-voltage power supply (not shown). In
As described above, the beamline unit 14 supplies the ion beam, with which the wafer W serving as a workpiece is to be irradiated, to the implantation processing chamber 16. The implantation processing chamber 16 includes an energy slit 38, a plasma shower device 40, side cups 42 (42R, 42L), a profiler cup 44, and the beam stopper 46 in order from the upstream side of the beamline A. As shown in
The energy slit 38 is provided downstream of the angular energy filter 36 and analyzes the energy of the ion beam incident into the wafer W together with the angular energy filter 36. The energy slit 38 is an energy defining slit (EDS) which is a slit horizontally long in the beam scanning direction (x direction). The energy slit 38 allows an ion beam having a desired energy value or a desired energy range to pass toward the wafer W, and shields the other ion beams.
The plasma shower device 40 is disposed downstream of the energy slit 38. The plasma shower device 40 supplies low-energy electrons to the ion beam and/or the front surface (wafer processing surface) of the wafer W depending on the amount of beam current of the ion beam and suppresses the accumulation (so-called charge-up) of positive charges on the wafer processing surface generated by ion implantation. The plasma shower device 40 includes, for example, a shower tube through which an ion beam passes and a plasma generating device that supplies electrons into the shower tube.
The side cups 42 (42R, 42L) measure the beam current of the ion beam during ion implantation processing into the wafer W. As shown in
The profiler cup 44 measures a beam current on the wafer processing surface. The profiler cup 44 is movable in the x direction by the operation of a drive unit 45, is retreated from an implantation region where the wafer W is located during the ion implantation, and is inserted into the implantation region when the wafer W is not located in the implantation region. The profiler cup 44 driven in the x direction can measure the beam current over an entire beam scanning range in the x direction. The profiler cup 44 may include a plurality of Faraday cups that are arranged in the x direction so that the beam currents at a plurality of positions in the beam scanning direction (x direction) can be simultaneously measured. Since the ion beam incident into the profiler cup 44 is incident into the implantation region where the wafer W serving as the workpiece is located during the ion implantation, the profiler cup 44 constitutes a first beam current measuring device that measures the beam current of the ion beam directed in the irradiation-enabled direction in which the wafer W can be irradiated. In addition, a beam current measuring device such as a Faraday cup may be provided on the beam stopper 46 with which the ion beam directed in the irradiation-enabled direction collides, and may serve as the first beam current measuring device.
At least one of the side cups 42 and the profiler cup 44 may include a single Faraday cup for measuring the amount of beam current or may include an angle measuring instrument for measuring the angle information of the ion beam. The angle measuring instrument includes, for example, a slit and a plurality of current detecting units provided apart from the slit in the beam traveling direction (z direction). The angle measuring instrument can measure the angle component or angle distribution of the beam in the slit width direction by measuring the ion beam passing through the slit with the plurality of current detecting units lined up in the slit width direction. At least one of the side cups 42 and the profiler cup 44 may include a first angle measuring instrument capable of measuring angle information in the x direction and/or a second angle measuring instrument capable of measuring angle information in the y direction.
The platen driving device 50 includes a wafer holding device 52, a reciprocating mechanism 54, a twist angle adjustment mechanism 56, and a tilt angle adjustment mechanism 58.
The wafer holding device 52 for holding the wafer W irradiated with the ion beam constitutes a support mechanism that supports the wafer W, and includes an electrostatic chuck as an electrostatic holding mechanism that holds the supported wafer W by electrostatic attraction. The wafer holding device 52 may include a temperature adjusting device for heating or cooling the wafer W into which ions are implanted. The temperature adjusting device may be a heating device that heats the wafer W to a temperature higher than the room temperature by +20° C. or higher, +50° C. or higher, or +100° C. or higher, or may be a cooling device that cools the wafer W to a lower temperature that is a temperature lower than the room temperature by -20° C. or lower, -50° C. or lower, or -100° C. or lower. The temperature of the wafer W affects the concentration distribution (implantation profiler) of ions implanted into the wafer W and the state of crystal defects (implantation damage) formed in the wafer W by the ion implantation. The processing of irradiating the wafer W having a temperature higher than room temperature with the ion beam is also referred to as high-temperature implantation. Additionally, the processing of irradiating the wafer W having a temperature lower than room temperature with the ion beam is also referred to as low-temperature implantation.
The reciprocating mechanism 54 is a drive mechanism that reciprocates the wafer holding device 52 including the support mechanism in a direction intersecting the ion beam. The reciprocating mechanism 54 reciprocates the wafer W held by the wafer holding device 52 in the y direction by reciprocating the wafer holding device 52 including a support mechanism in a reciprocating motion direction (y direction) perpendicular to the beam scanning direction (x direction). In
The twist angle adjustment mechanism 56 constituting an implantation angle adjustment mechanism is a mechanism that adjusts the rotation angle of the wafer W, and adjusts the twist angle between an alignment mark provided at an outer peripheral portion of the wafer W and a reference position by rotating the wafer W with a normal line perpendicular to the wafer processing surface as a rotation axis at the center of the wafer processing surface. Here, the alignment mark of the wafer W is, for example, a notch or an orientation flat provided at an outer peripheral portion of the wafer W and serves as a reference for an angular position in the crystal direction of the wafer W or in the circumferential direction of the wafer W. The twist angle adjustment mechanism 56 is provided between the wafer holding device 52 and the reciprocating mechanism 54 and is reciprocated by the reciprocating mechanism 54 together with the wafer holding device 52.
The tilt angle adjustment mechanism 58 constituting the implantation angle adjustment mechanism is a mechanism that adjusts the tilt of the wafer W and adjusts the tilt angle between the traveling direction of the ion beam directed to the wafer processing surface and the normal line of the wafer processing surface. In the example of
The platen driving device 50 holds the wafer W such that the wafer W is movable between the ion implantation position where the wafer W is irradiated with the ion beam and a transfer position where the wafer W is transferred to or from the wafer transfer device 18. That is, the platen driving device 50 constitutes a moving device that moves the wafer holding device 52 between the ion implantation position where the wafer W supported with the wafer holding device 52 is irradiated with the ion beam, and the transfer position where the wafer transfer device 18 can transfer the wafer W to or from the wafer holding device 52.
The beam stopper 46 is provided on the most downstream side of the beamline A and is mounted on, for example, the inner wall of the implantation processing chamber 16. An ion beam in a case where the wafer W and the profiler cup 44 are not present on the beamline A is incident into the beam stopper 46. The beam stopper 46 is disposed near the transfer port 48 that connects the implantation processing chamber 16 and the wafer transfer device 18 to each other, and is provided at a position vertically below (-y direction) the transfer port 48 in the example of
The ion implanter 10 further includes a control device 60 that controls the overall operation thereof. The control device 60 is realized by the cooperation between hardware resources such as a central arithmetic processing device of a computer, a memory, an input device, an output device, and peripheral units connected to a computer, and software executed using the hardware resources. Regardless of the type and installation location of the computer, each function of the control device 60 may be realized by the hardware resources of a single computer, or may be realized by combining the hardware resources distributed to a plurality of computers. Details of the control device 60 will be described below.
The load port 62 can receive a plurality of wafer containers 72a, 72b, 72c, 72d (hereinafter, collectively referred to as wafer containers 72). The wafer transfer device 18 transfers an unprocessed wafer Wa in the wafer container 72 to the implantation processing chamber 16 and transfers a processed wafer Wb subjected to the ion implantation processing in the implantation processing chamber 16 out to the wafer container 72.
In the shown state, the processed wafer Wb is inside the implantation processing chamber 16 and is supported with the wafer holding device 52 in front of a processing chamber gate valve 86 (described below) corresponding to the transfer port 48 in
The atmospheric transfer unit 64 includes a first atmospheric transfer mechanism 74a, a second atmospheric transfer mechanism 74b, and an alignment device 76. The first atmospheric transfer mechanism 74a is provided between the load port 62 and the first load lock chamber 66a. The first atmospheric transfer mechanism 74a includes, for example, two robot arms for transferring wafers. The first atmospheric transfer mechanism 74a transfers a wafer before the ion implantation processing into the atmospheric transfer unit 64 from a first wafer container 72a or a second wafer container 72b, and transfers the ion implantation-processed wafer out to the first wafer container 72a or the second wafer container 72b outside the atmospheric transfer unit 64. The first atmospheric transfer mechanism 74a transfers the unprocessed wafer before alignment to the alignment device 76 and transfers the aligned unprocessed wafer from the alignment device 76. The first atmospheric transfer mechanism 74a transfers the aligned unprocessed wafer into the first load lock chamber 66a and transfers the ion implantation-processed wafer from the first load lock chamber 66a.
The second atmospheric transfer mechanism 74b is provided between the load port 62 and the second load lock chamber 66b. The second atmospheric transfer mechanism 74b includes, for example, two robot arms for transferring wafers. The second atmospheric transfer mechanism 74b transfers a wafer before the ion implantation processing into the atmospheric transfer unit 64 from a third wafer container 72c or a fourth wafer container 72d, and transfers the ion implantation-processed wafer out to the third wafer container 72c or the fourth wafer container 72d outside the atmospheric transfer unit 64. The second atmospheric transfer mechanism 74b transfers the unprocessed wafer before alignment to the alignment device 76 and transfers the aligned unprocessed wafer from the alignment device 76. The second atmospheric transfer mechanism 74b transfers the aligned unprocessed wafer into the second load lock chamber 66b and transfers the ion implantation-processed wafer from the second load lock chamber 66b.
The alignment device 76 is a device for adjusting the center position and the rotation position (rotation angle) of the wafer. The alignment device 76 detects the alignment mark such as a notch provided on the wafer to adjust the center position and the rotation position of the wafer to desired positions with reference to the alignment mark. Since the center position and the rotation position of the unprocessed wafer transferred into the atmospheric transfer unit 64 from the wafer container 72 are not necessarily aligned, the unprocessed wafer is positioned (aligned) by the alignment device 76 before being transferred into the load lock chambers 66a or 66b. The alignment device 76 is provided at a position between the first atmospheric transfer mechanism 74a and the second atmospheric transfer mechanism 74b. The alignment device 76 is provided, for example, at a position vertically below (-y side) the buffer chamber 70.
Each of the first load lock chamber 66a and the second load lock chamber 66b is provided between the atmospheric transfer unit 64 and the intermediate transfer chamber 68. Each of the first load lock chamber 66a and the second load lock chamber 66b is, for example, adjacent to the atmospheric transfer unit 64 in the z direction and adjacent to the intermediate transfer chamber 68 in the x direction. The intermediate transfer chamber 68 is provided adjacent to the implantation processing chamber 16, for example, in the z direction. The buffer chamber 70 is provided adjacent to the intermediate transfer chamber 68, for example, in the z direction.
The intermediate transfer chamber 68 is maintained in a medium vacuum state of about 10-1 Pa in a steady state. An evacuating device (not shown) composed of a turbo molecular pump or the like is connected to the intermediate transfer chamber 68. Meanwhile, the atmospheric transfer unit 64 is provided under atmospheric pressure and transfers the wafer in the air atmosphere. The first load lock chamber 66a and the second load lock chamber 66b are chambers or spaces that are partitioned to realize wafer transfer between the intermediate transfer chamber 68 maintained in the medium vacuum state and the atmospheric transfer unit 64 under the atmospheric pressure. Each of the first load lock chamber 66a and the second load lock chamber 66b can be evacuated or opened to the air atmosphere during the wafer transfer. A roughing vacuum pump such as an oil rotary vacuum pump or a dry vacuum pump is connected for evacuation of each of the first load lock chamber 66a and the second load lock chamber 66b.
The first load lock chamber 66a includes a first atmospheric-side gate valve 78a provided between the first load lock chamber 66a and the atmospheric transfer unit 64, a first intermediate gate valve 80a provided between the first load lock chamber 66a and the intermediate transfer chamber 68, and a first temperature adjusting device 82a. Similarly, the second load lock chamber 66b includes a second atmospheric-side gate valve 78b provided between the second load lock chamber 66b and the atmospheric transfer unit 64, a second intermediate gate valve 80b provided between the second load lock chamber 66b and the intermediate transfer chamber 68, and a second temperature adjusting device 82b.
In a case where the first load lock chamber 66a is evacuated or opened to the air atmosphere, the first atmospheric-side gate valve 78a and the first intermediate gate valve 80a are closed. In a case where the wafer is transferred between the atmospheric transfer unit 64 and the first load lock chamber 66a, the first atmospheric-side gate valve 78a is opened in a state where the first intermediate gate valve 80a is closed. In a case where the wafer is transferred between the intermediate transfer chamber 68 and the first load lock chamber 66a, the first intermediate gate valve 80a is opened in a state where the first atmospheric-side gate valve 78a is closed.
Similarly, in a case where the second load lock chamber 66b is evacuated or opened to the air atmosphere, the second atmospheric-side gate valve 78b and the second intermediate gate valve 80b are closed. In a case where the wafer is transferred between the atmospheric transfer unit 64 and the second load lock chamber 66b, the second atmospheric-side gate valve 78b is opened in a state where the second intermediate gate valve 80b is closed. In a case where the wafer is transferred between the intermediate transfer chamber 68 and the second load lock chamber 66b, the second intermediate gate valve 80b is opened in a state where the second atmospheric-side gate valve 78b is closed.
The first temperature adjusting device 82a heats or cools the wafer transferred into the first load lock chamber 66a to adjust the wafer temperature. The first temperature adjusting device 82a may heat or cool the wafer before the ion implantation processing to adjust the wafer temperature to a temperature suitable for the ion implantation processing. The first temperature adjusting device 82a may cool or heat the ion implantation-processed wafer to adjust the wafer temperature to room temperature or a temperature close to room temperature.
The second temperature adjusting device 82b heats or cools the wafer transferred into the second load lock chamber 66b to adjust the wafer temperature. The second temperature adjusting device 82b may heat or cool the wafer before the ion implantation processing to adjust the wafer temperature to a temperature suitable for the ion implantation processing. The second temperature adjusting device 82b may cool or heat the ion implantation-processed wafer to adjust the wafer temperature to room temperature or a temperature close to room temperature.
The intermediate transfer chamber 68 includes an intermediate transfer mechanism 84. The intermediate transfer mechanism 84 includes, for example, two robot arms for transferring wafers. The intermediate transfer mechanism 84 transfers the wafer between the intermediate transfer chamber 68 and each of the chambers adjacent to the intermediate transfer chamber 68. The intermediate transfer mechanism 84 transfers the wafer before the ion implantation processing from the first load lock chamber 66a and transfers the ion implantation-processed wafer into the first load lock chamber 66a. The intermediate transfer mechanism 84 transfers the wafer before the ion implantation processing from the second load lock chamber 66b and transfers the ion implantation-processed wafer into the second load lock chamber 66b. The intermediate transfer mechanism 84 transfers the wafer before the ion implantation processing into the implantation processing chamber 16 and transfers the ion implantation-processed wafer from the implantation processing chamber 16. The intermediate transfer mechanism 84 transfers the wafer before the ion implantation processing or the ion implantation-processed wafer into the buffer chamber 70 and transfers the wafer before the ion implantation processing or the ion implantation-processed wafer from the buffer chamber 70.
A processing chamber gate valve 86 is provided between the implantation processing chamber 16 and the intermediate transfer chamber 68. The processing chamber gate valve 86 is opened in a case where the wafer is transferred between the implantation processing chamber 16 and the intermediate transfer chamber 68. The processing chamber gate valve 86 is closed in a case where the ion implantation processing is performed on the wafer in the implantation processing chamber 16.
The buffer chamber 70 is a chamber for temporarily storing the wafer transferred into the intermediate transfer chamber 68. The buffer chamber 70 includes a buffer chamber gate valve 88 and a third temperature adjusting device 90. The buffer chamber gate valve 88 provided between the intermediate transfer chamber 68 and the buffer chamber 70 is opened in a case where a wafer is transferred between the intermediate transfer chamber 68 and the buffer chamber 70, and is closed in a case where the third temperature adjusting device 90 adjusts the wafer temperature in the buffer chamber 70.
The third temperature adjusting device 90 heats or cools the wafer transferred into the buffer chamber 70 to adjust the temperature of the wafer. The third temperature adjusting device 90 may heat or cool the wafer before the ion implantation processing to adjust the wafer temperature to a temperature suitable for the ion implantation processing. The third temperature adjusting device 90 may cool or heat the ion implantation-processed wafer to adjust the wafer temperature to room temperature or a temperature close to room temperature.
Although an example of the wafer transfer device 18 is shown in
“PRESENT” and “ABSENT” in the “FIRST WAFER” in a first row of
“ON” and “OFF” in the “WAFER TRANSFER DEVICE” in a fourth row of
“ON” and “OFF” in the “BEAM DEFLECTION DEVICE” in a fifth row of
In the step of “FIRST WAFER ION IMPLANTATION” in a first column of
In the step (a) of “BEAM DEFLECTION” in a second column of
In the step (b) of “DECHUCKED” in a third column of
In the step of “TRANSFER FIRST WAFER FROM/TRANSFER SECOND WAFER TO” in a fourth column of
In the step (e) of “CHUCKED” in a fifth column of
In the step (f) of “BEAM DEFLECTION RELEASE” in a sixth column of
In S3 corresponding to the step (d) in
In S6 corresponding to the step (f) and the “SECOND WAFER ION IMPLANTATION” of
Subsequently, modification examples of the basic operation of the above-mentioned ion implanter 10 will be described.
In a first modification example, the beam blocking mechanism 28 is used. The processor 61 switches the beam blocking mechanism 28 to the blocking state after the “BEAM DEFLECTION” step (a) in
In a second modification example, in addition to the beam blocking mechanism 28, the first beam current measuring device 46 and/or the second beam current measuring device 42 is used. In a case where a beam current equal to or greater than a first predetermined value is not measured with the first beam current measuring device 46 (such as the beam stopper 46 or the like configured as a beam current measuring device) that measures a beam current of an ion beam directed in the irradiation-enabled direction, the processor 61 may make a determination of being in the irradiation-disabled state to switch the beam blocking mechanism 28 to the blocking state. That is, in a case where the beam current measured with the first beam current measuring device 46 is smaller than the first predetermined value, there is a risk that the intensity of the ion beam to be used for the ion implantation processing in the implantation processing chamber 16 is insufficient. Therefore, the beam blocking mechanism 28 is switched to the blocking state, and then the ion implantation processing is interrupted or stopped. In addition to or instead of the first beam current measuring device 46, in a case where the beam current of the first predetermined value or more or the beam current of a predetermined value equivalent to the first predetermined value or more is not measured with the second beam current measuring device 42 (side cups 42 or the like), the processor 61 may make a determination of being in the irradiation-disabled state to switch the beam blocking mechanism 28 to the blocking state.
In a case where a beam current equal to or greater than a second predetermined value is measured with the second beam current measuring device 42 (side cups 42 or the like) that measures the beam current of the ion beam directed in the irradiation-disabled direction, the processor 61 may make a determination of being in the irradiation-disabled state to switch the beam blocking mechanism 28 to the blocking state. That is, in a case where the beam current measured with the second beam current measuring device 42 is equal to or greater than the second predetermined value, there is a risk that the intensity of the ion beam that is not used for the ion implantation processing in the implantation processing chamber 16 is excessive. Therefore, the beam blocking mechanism 28 is switched to the blocking state, and then the ion implantation processing is interrupted or stopped. In addition, the second predetermined value is preferably set such that the beam current density converted from the second predetermined value is greater than the beam current density converted from the first predetermined value.
In a third modification example, the beam scanning device 32 is also used as the beam deflection device 24. For example, the beam scanning device 32 realizes the function of the beam deflection device 24 instead of or in addition to the beam park device 24 that has functioned as the beam deflection device 24 in
In a case where an original beam scanning function is realized, the beam scanning device 32 performs the reciprocating scanning in the predetermined scanning angle range in the x direction with the ion beam with which the wafer W is irradiated. Here, the scanning angle range is an angle range including the irradiation-enabled direction (the direction of the beamline A that can reach a wafer), and a shown θ2 is a maximum scanning angle formed between an outermost angle of the scanning angle range and a reference trajectory direction (the direction of the beamline A in a non-scanning state in which a voltage to be applied between a pair of scanning electrodes of the beam scanning device 32 is substantially zero). In other words, the scanning angle range of the beam scanning device 32 is a range of ±θ2 with respect to the reference trajectory direction.
On the other hand, in a case where the beam scanning device 32 functions as the beam deflection device 24, the ion beam is deflected in the irradiation-disabled direction outside the scanning angle range. Here, a deflection angle θ1 of the ion beam is an angle formed between the irradiation-disabled direction and the reference trajectory direction, and is greater than the maximum scanning angle θ2 (θ1 > θ2). Since the wafer W is not disposed on the path of the ion beam deflected by the deflection angle θ1, the deflection angle θ1 is set to the irradiation-disabled direction in which the wafer W cannot be irradiated with the ion beam. In addition, the beam scanning device 32 functioning as the beam deflection device 24 may deflect the ion beam at a deflection angle of -θ1. Additionally, a beam dump or the like may be provided on the path of the ion beam deflected at the deflection angle θ1 (or -θ1) such that the ion beam collides with the beam dump or the like and is shielded.
In the steps of “FIRST WAFER ION IMPLANTATION” and “SECOND WAFER ION IMPLANTATION” in the basic operation of
According to the above-described embodiment and/or modification examples, since the irradiation-disabled state during the replacement of a wafer in the steps (a) to (e) of
The present invention has been described above on the basis of the embodiment. The embodiment is an example, and it will be understood by those skilled in the art that various modification examples are possible for the combinations of the respective components and the respective processes and that such modification examples are also within the scope of the present invention.
In addition, the functional configurations of the respective devices described in the embodiment can be realized by hardware resources or software resources or by the cooperation between the hardware resources and the software resources. Processors, ROMs, RAMs, and other LSIs can be used as the hardware resources. Programs such as operating systems and applications can be used as the software resources.
It should be understood that the invention is not limited to the above-described embodiment, but may be modified into various forms on the basis of the spirit of the invention. Additionally, the modifications are included in the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-021334 | Feb 2022 | JP | national |
